From the Zimet/Black Collection at  SMECC - Photo (c)  SMECC                       From the Zimet/Black Collection at  SMECC - Photo (c)  SMECC

From TDI 2nd Conference Program 1977   -   From the Harry G. Lang Collection at  SMECC

years later....From TDI Bluebook

So apparently AM-COM bought MAGSAT or evolved  from them!?!?

Deaf Locksmith Uses TTY, Magsat In His Work

By Robert Pagel, The Deaf American, February 1977  

 

With the national unemployment figure at an all-time high in recent years, break-ins and burglaries have rapidly become the rule rather than the exception.  This spin-off has resulted in both law-enforcement officials and locksmiths putting in a lot of overtime work—the law enforcement people trying to catch burglars, and the locksmiths trying to prevent more burglaries.  As a result, the overall picture resembles an imaginary merry-go-round: the locksmiths and police trying to outwit the burglars and vice versa.

 

In the midst of that and riding the booming demand for increased security locking devices are many lock and key shops all across the nation.  One of these, in particular, is Bill’s Key Shop in Madison, Wisconsin.  And one of the spark plugs that keep this business operating in high gear is deaf William (Bill) Sherer, Jr., a 1955 graduate of the Wisconsin School for the Deaf.  A bonded locksmith, Bill is one of four equal partners running the family business which was established by his father, William Scherer, Sr., 30 years ago.  The fourth partner, along with Bill Jr., and his parents is his brother, Ed “Duke” Scherer.

 

The beginning of the business actually goes back 50 years, when Bill’s father started clerking and cutting keys at a hardware store on University Avenue in Madison.  That hardware store was close to the heart of the University of Wisconsin campus and much of the business then, as now, came from University students.  The present location of the Key Shop is only two blocks from where the hardware store used to be.

 

Over the years Bill’s Key Shop has built up a solid reputation for quality locksmithing, among both University students and townspeople.  As an example, one customer who moved to Illinois sends back to Bill’s for keys he needs.  The shop also has some third-generation customers.

 

It was into this kind of setting that Bill, Jr. sort of backed.  In school at Delavan, he learned the printing trade, fully expecting to make a living at it as so many deaf before him had.  But it was not to be.

 

After graduation from WSD, he worked as a Linotype operator in several printing establishments before settling down with Madison Newspapers, Inc., and joining the International Typographical Union.  After 12 years in printing he started working part-time at his father’s key shop, stamping blank keys with the shop’s name, hanging them on their hooks and other simple tasks connected with locks and keys.  This was partly because they needed help due to an increase in business.  His father had retired, but subsequently returned to full-time work.

 

Two years later, after having worked full-time at the Newspapers and part-time for his father, Bill concluded that there was more solid future for him at the Key Shop, and reversed the basis of his work—going full-time at the Key Shop and part-time at the Newspapers.  Eventually he quit the Newspapers altogether to devote full-time to the Key Shop.

 

Soon after his graduation from school, Bill had started plowing snow on a contract basis for a few businesses such as service stations, hotels, apartment buildings, etc.  Now, after some 15 years or so of it, he is still going strong.  For this winter-time “sideline” he drives a 1975 IHC Scout 4-wheel-drive rig—the fifth one of similar style he has used.  This job is taken care of whenever the weather dictates, before his regular day at the Key Shop starts.  So he rises pretty early some days.  And his being a partner in the business helps to make his hours flexible when some snow plowing is necessary.

 

Another “sideline”—or hobby—of his is scuba diving, though he has had little time for it in recent years.

 

Working into the Key Shop business was not difficult for Bill, since both his mother and brother use the manual alphabet and sign language.  As he found his way around in things and spent more time out of the shop on service calls, he put his imagination to work.  One of the time-consuming problems for him was that he, after completing one job, would have to drive back to the shop to find out what and where his next job was, have his last customer call in for him, or stop by the home of friends and have them call for him.  Any way it was done, it resulted in inconvenience for someone. 

 

It was about this time that teletypewriters, and other similar devices for the deaf, were coming into their own.  So Bill thought: Why not carry a Magsat unit with him in the truck and install a TTY at the shop to facilitate communication between the two from the field?  So he bought one of each and now carries the Magsat with him in the truck, while the TTY stands in the rear of the Key Shop.  When he finishes one job in the field, and has no more orders, he calls the shop from one of a number of locations around the city where he knows there is a pay phone which will accommodate his Magsat hook-up.

Occasionally, if his last customer has the right type phone in his home, Bill will call via the Magsat from there.

 

When the inquiry from Bill in the field comes into the Key Shop on the TTY, brother Duke—or, if he is out, Bill’s mother—will answer it with instructions where Bill is to go for his next job.  Occasionally, Billy Scott, an employee of the Key Shop, will give instructions on the TTY.  Scott is a relative of the Sherers and also knows the manual alphabet and sign language. 

 

In this way, a minimum of time is lost between servicing customers around the city.  Both Bill and his parents have found it an efficient and time-saving system.  Since calls for service come into the Key Shop from different parts of the city all day long, it is important that they be relayed to the trucks in the field as soon as possible. 

 

Three trucks are available for service calls, and it just may be symbolic that Bill drives the largest one.  A smaller one is used by Duke when it is necessary for him to help out in the field.  And an even smaller one is driven by Lou Lombardo, another employee who works outside the shop most all the time.  Then Bill’s father uses a station wagon any time it is necessary for him to leave the shop to help with difficult jobs, or open safes, where his more extensive experience might be needed.

 

Besides taking calls and answering the TTY at the shop, Bill’s mother also cuts keys and serves walk-in customers.  Bill’s wife, Diana, who is also deaf and a graduate of WSD, helps out by mailing monthly statements and reconciling payments with invoices. 

 

On a wall of the Key Shop there is a map of Madison with seven red dots scattered around on it.  These red dots represent locations around the city where Bill usually goes to call the Key Shop from the field.  Of course, it’s possible to call from any pay phone if it has the right kind of hook-up for his Magsat.  But these seven are the main ones, which Bill has established as being most convenient for his purposes.

 

Hook-ups at two of these seven locations were installed especially for Bill’s use of the Magsat.  For example, one of them, at a large east side shopping center, was installed as a courtesy after Bill explained his needs to the manager of the shopping center.  The convenience of that electrical outlet at that location is shown in one of the photos accompanying this story.

 

Emergency 24-hour-a-day service is one of the features of this locksmith firm, and Bill is right in there holding up his end of it.  After-hours calls or service that come into the Key Shop are relayed over a special telephone hook-up to Duke’s home.  If the call comes from the east side of Madison (where Bill lives), Duke calls Bill’s home by regular phone where his 15-year-old daughter, Mary Lynn, takes the message for him.  Bill then goes out on the service call, using the truck which is always with him. Then there is another TTY in the Sherer home, over which requests for help sometimes come—either from the Key Shop or from deaf friends.

 

Bill handles anything and everything in the way of lock and key work, and says he has never been stumped by anything.  He has no favorite type of work, and enjoys all aspects of it.  Such things, as installing heavy-duty deadbolts, simple door knobs, opening locked cars for people, mailboxes, safe deposit boxes, changing safe combinations, changing cylinder locks, re-keying locks, letting people into their locked houses, etc. are just routine for him.  A common service call is from people who have locked themselves out of their car at a parking ramp.  Usually this type of call is handled with the smallest truck—which can negotiate the low-ceiling clearance floors of the multiple-story parking ramps.

 

Work for large customers such as banks, hospitals, apartment buildings, hotels, etc. is taken in stride by Bill.  It is interesting that the Key Shop generally does not advise its customers in advance that a deaf service man will call on them.  And rapport between Bill and the shop’s customers has been very good, considering that Bill depends almost entirely on natural hand signs and the pad and pencil for conversing with his customers.  As a matter of fact, Bill recalls that there have been only two instances over the years where the customers did not want to do business with him via pad and pencil after he had arrived at the job site.  In these two cases the customer called the Key Shop again and requested that someone else be sent out.  (It makes one wonder whether they didn’t want to write, or if they didn’t know how).  Bill says that many of his customers remember him long after he has forgotten them.

 

Another—and important—aspect of the Key Shop’s work is demonstrating the various locks and security devices at home, shows, schools and to law enforcement people.  Bill is active in this type of thing to the extent of helping his father and brother wherever he can.

 

It is at such affairs as home shows that some people, after seeing what is available in the way of good locks, suddenly wake up and realize that they need more security on their home and apartment doors.  And Bill says it is surprising how ignorant many people are of the locks on their homes at the same time they have valuable things laying around that may not be covered by insurance.  Oftentimes it is only after a break-in—not before—that people are inclined to believe that it can happen to them.

 

Mrs. Scherer, Bill’s mother, feels that locksmithing is a good line of work for the deaf to become involved in.  She should know, for she has been around both the deaf and locksmithing for many years.  She also comments that, in spite of all the ignorance prevalent regarding good locks, people ARE becoming more security-conscious.  And this would seem to indicate that Bill has his work cut out for him for a long time to come. 

 

 MAGNETICALLY OPERATED ELECTRICAL SWITCH   --  United States Patent 3863182 


  

Title:

MAGNETICALLY OPERATED ELECTRICAL SWITCH 


United States Patent 3863182 


Abstract:

An electrical switch has a freely movable magnetic ball contact maintained in a 
first position out of engagement with at least one of a plurality of stationary 
electrical contacts by a permanent magnet. The ball contact is movable to a 
second position wherein it engages all of the contacts in response to magnetic 
influence exerted thereon by an iron rod carried by a reciprocally movable push 
button and disposed within a flux path of the magnet. The rod exerts greater 
magnetic influence on the ball contact than magnet during only an initial 
portion of push button travel toward a fully depressed position whereby to cause 
the ball contact to return to its first position in response to magnetic 
influence of the magnet before the push button reaches its fully depressed 
position. 


 


Application Number:

05/453722 


Publication Date:

01/28/1975 


Filing Date:

03/22/1974 


Export Citation:

Click for automatic bibliography generation 


Assignee:

Magsat Corporation (West Hartford, CT) 



Primary Class:

335/207


Other Classes:

335/280 


International Classes:

H01H13/50; H01H36/00; H01H41/04; H01H13/50; H01H36/00; H01H41/00; (IPC1-7): 
H01H13/00 


Field of Search:

335/205,206,207,280,306 200 


View Patent Images:

Download PDF 3863182 PDF help


US Patent References:




3815066

MAGNETIC KEY MECHANISM OR THE LIKE

June 1974

Vinal




3535664

DEVICE FOR BREAKING A BEAM OF LIGHT RAYS OR THE LIKE AND/OR ELECTRIC CURRENT

October 1970

Staar




3261944

Magnetic switch

July 1966

Sherwood




3072769

Control mechanism

January 1963

Roeser






Primary Examiner:

Broome, Harold 


Attorney, Agent or Firm:

McCormick, Paulding & Huber 



Claims:

1. An electrical switch comprising a plurality of electrical contacts spaced 
from each other, a permanent magnet mounted in fixed position relative to said 
electrical contacts, a magnetic switching part disposed within the magnetic 
influence of said magnet and maintained in one switching position by the 
magnetic attraction of said magnet, said switching part in said one position 
being out of electrical contact with at least one of said electrical contacts 
and being movable to another position wherein it is in electrical contact with 
each of said electrical contacts, an operating part supported for movement 
relative to said electrical contacts and said magnet between first and second 
positions, a ferromagnetic element carried by said operating part and disposed 
within the magnetic influence of said magnet and in close proximity to said 
switching part when said operating part is in its first position and said 
switching part is in said one position, said ferromagnetic element exerting a 
greater magnetic attraction for said switching part than said magnet when said 
operating part is in its first position and during at least a portion of the 
travel of said operating part from its first toward its second position, said 
switching part being movable from its one to its other position with said 
operating part when the latter part is moved from 

2. An electrical switch as set forth in claim 1 wherein said ferromagnetic 
element exerts greater magnetic attraction for said switching part than said 
magnet during only the initial portion of the travel of said operating part from 
its first toward its second position, said switching part attains its other 
position in response to movement of said operating part from its first toward 
its second position before said operating part attains its second position, said 
magnet exerts greater attraction for said switching part than said ferromagnetic 
element after said switching part attains its other position and said switching 
part moves from its other position to its one position in response to magnetic 
attraction of said magnet during the final portion of the travel of said 
operating part 

3. An electrical switch as set forth in claim 1 wherein said electrical contacts 
comprise three stationary contacts, said switching part passes through an 
intermediate position wherein it is in electrical contact with two of said 
contacts in traveling from its one to its other position, and said switching 
part remains in electrical contact with said two contacts during its movement 
from said intermediate position to its other position in response to movement of 
said operating part from its first toward its 

4. An electrical switch as set forth in claim 3 wherein said switching part 

5. An electrical switch as set forth in claim 4 wherein said ferromagnetic 

6. An electrical switch as set forth in claim 2 wherein said switch includes a 
hollow housing which has a bore, said electrical contacts comprise stationary 
contacts fixedly mounted in said housing, said operating part comprises a push 
button which has a hollow shank slidably received in said bore, and said 
switching part is disposed generally 

7. An electrical switch has set forth in claim 6 wherein said switching 

8. An electrical switch as set forth in claim 7 wherein one of said stationary 
contacts partially defines said bore, said shank has a slot therein adjacent 
said one stationary contact, and said ball engages said 

9. An electrical switch as set forth in claim 8 wherein said one stationary 
contact comprises means for supporting said magnet in fixed position in 

10. An electrical switch as set forth in claim 7 wherein said ferromagnetic 

11. An electrical switch as set forth in claim 1 wherein said switch includes 
means for biasing said operating part in one direction toward its first position 
and said ferromagnetic element comprises means for limiting 

12. An electrical switch as set forth in claim 11 wherein said switch includes a 
housing which has a slot therein, said operating member is supported by said 
housing for movement relative thereto, and said ferromagnetic element comprises 
a rod received in said slot. 




Description:

BACKGROUND OF THE INVENTION 

This invention relates in general to electrical switches and deals more 
particularly with an improved magnetically operated electrical switch suitable 
for use as a keyboard switch or the like. 

The switch of the present invention is particularly adapted for use as a 
keyboard switch on an electric typewriter, business machine, computer or like 
apparatus which requires single pulse switch output during each switching cycle. 
In a keyboard switch of the aforedescribed type, it is generally required that 
the electrical output of the switch be isolated from and wholly independent of 
the mechanical output of the operator. Thus, the operator controls the 
occurrence of switch pulse output but not the duration thereof. It is further 
desirable that such a switch have a tactile feedback characteristic to indicate 
to the keyboard operator, as by sharp reduction of key stroke pressure, that a 
character has been transmitted. 

Accordingly, the general aim of the present invention is to provide an improved 
magnetically operated switch which possesses the aforedescribed desired 
operational characteristics and which is of simple durable construction for low 
cost manufacture. 

SUMMARY OF THE INVENTION 

In accordance with the present invention, an improved electrical switch is 
provided which comprises a plurality of stationary electrical contacts, a 
permanent magnet mounted in fixed position relative to the contacts, a movable 
switching part maintained by the magnet in one switching position out of 
engagement with at least one of the contacts, an operating part supported for 
movement relative to the contacts and magnet between first andd second 
positions, and a ferromagnetic element carried by the operating part and 
disposed within the magnetic influence of the magnet and in close proximity to 
the switching part when the operating part is in its first position and the 
switching part is in its one position. The ferromagnetic element exerts a 
greater magnetic attraction for the switching part than the magnet when the 
operating part is in its first position and during at least a portion of its 
travel toward its second position whereby the switching part moves with the 
operating part to another position wherein it engages each of the stationary 
contacts when the operating part is moved from its first position toward its 
second position. 

BRIEF DESCRIPTION OF THE DRAWING 

FIG. 1 is an axial sectional view through an electrical switch embodying the 
present invention. 

FIG. 2 is a sectional view taken along the line 2--2 of FIG. 1. 

FIG. 3 is a sectional view taken generally along the line 3--3 of FIG. 2. 

FIG. 4 is a fragmentary sectional view taken along the line 4--4 of FIG. 1. 

FIG. 5 is a sectional view similar to FIG. 1 but shows the operating button in a 
partially depressed position. 

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 

Turning now to the drawing, an electrical switch embodying the present invention 
and indicated generally at 10, comprises a switch housing designated generally 
by the numeral 12 supporting a plurality of spaced stationary contacts 14, 16 
and 18 and a permanent magnet 20 associated with the contact 14. The illustrated 
switch 10 is particularly adapted for use as a keyboard switch and further 
includes an operating part or push button indicated generally at 22 which 
carries a ferromagnetic element 24. The push button is supported by the housing 
12 for movement relative thereto and controls movement of a switching part or 
movable spherical contact 26 preferably made from steel and contained in the 
housing and within magnetic influence of the magnet 20. The movable magnetic 
ball contact 26 is maintained in one position out of electrical contact with at 
least one of the stationary contacts by the magnetic attraction of the magnet 
and is movable to another position wherein it is in electrical contact with each 
of the stationary contacts to establish electrical connection therebetween in 
response to movement of the operating part. 

Considering now the housing 12 in further detail, it includes a hollow generally 
rectangular base 28 and a terminal board 30 secured to the base by threaded 
fasteners 32, 32 as best shown in FIG. 3. The base 28 has a reduced neck portion 
at its upper end which partially defines a generally rectangular bore 34 which 
extends through the base. A downwardly opening recess 36 in one side of the base 
communicates with the bore 34 as best shown in FIG. 2. 

The stationary contacts 14, 16 and 18 are supported on the terminal board 30 and 
have terminal portions which extend downwardly therethrough for connection in an 
external circuit or, if desired, to a printed circuit associated with the 
terminal board. The contact 14 comprises a generally rectangular plate which is 
disposed within the base and has its marginal side edges received and supported 
in opposing slots 38, 38 formed in the base as best shown in FIG. 2. The contact 
14 forms a partition or dividing wall between the recess 36 and the bore 34 and 
defines a continuation of one wall of the rectangular bore 34, as best shown in 
FIG. 1. A pair of bent mounting clips 40, 40 struck from the contact 14 support 
the magnet 20 within the recess 36. The contacts 16 and 18 are generally 
cylindrical and project upwardly from the terminal board generally within a 
plane through the bore axis. Each of the contacts 16 and 18 has a generally 
conical upper end portion to provide a contact surface for electrical contact 
engagement with the ball contact 26. The contacts 16 and 18 are spaced from each 
other and from the contact 14. It should be noted that the contact 16 is of 
somewhat greater length than the contact 18 and extends for a slightly greater 
distance above the terminal board 30 than the contact 18. 

The push button or key is preferably molded from plastic or like material and 
has a button portion 42 and an integral hollow shank 44 which depends from the 
button portion. The shank has a generally rectangular cross sectional 
configuration which complements the cross-sectional configuration of the bore 34 
in which it is slidably received. At its lower end, the shank 44 has a 
downwardly opening slot 46 formed in the wall thereof adjacent the contact 14. 
The ferromagnetic element 24 comprises an iron rod which extends transversely 
through the lower end of the shank portion 44 between the contact 14 and the 
contacts 16 and 18. The end portions of the rod 24 project from opposite sides 
of the shank 44 and into a downwardly opening slot 48 formed in the base 28. The 
end portions of the rod cooperate with the upper wall of the slot 48 to retain 
the push button 22 in assembly with the housing 12 and function as a stop to 
limit its upward travel relative to the housing. The push button 22 is biased to 
a projected or first position, indicated by full lines in FIG. 1, by a 
compression spring 50 which surrounds the neck portion of the base 28 and acts 
between the base and the button portion 42. The push button 22 is manually 
movable against bias of the spring 30 to a fully depressed or second position 
indicated by broken lines in FIG. 1. 

The spherical or ball contact 26 is disposed in the housing 12 within the 
magnetic influence of the magnet 20 and more specifically within the hollow 
shank 44 and above the iron rod 24. The magnet is preferably of the type which 
includes a plurality of poles arranged in alternate series. The illustrated 
magnet 20 has three alternate poles arranged substantially as indicated in FIG. 
1. It should be further noted that when the push button 22 is in its projected 
position, the ferromagnetic rod 24 is disposed in close proximity to and 
preferably in contact with the ball contact 26, substantially as shown in FIG. 
1. 

When the push button 22 is in its projected position, the ball contact 26 is 
maintained in a generally central position relative to the magnet 20 and in 
electrical contact with the contact 14 by the magnetic attraction of the magnet. 
However, when the ball contact 26 is in the latter position, as it appears in 
FIG. 1, it is out of electrical contact with the stationary contact 16 and 18, 
as best shown in FIG. 3. When the push button 22 is in its projected position, 
the rod 24 is generally adjacent the ball contact 26 and within the magnetic 
influence of the magnet 20 and acts as a temporary magnet to exert further 
magnetic influence upon the ball 26. During initial movement of the push button 
22 from its projected toward its depressed position, the rod 24 exerts a 
substantially greater influence upon the ball contact 26 than the magnet 20. 
Thus, the ball contact 26 moves downward with the push button and toward the 
stationary contacts 16 and 18 in rolling or sliding engagement with the contact 
14. Due to the height differential between the contacts 14 and 16 relative to 
the base 30, the ball contact 26 establishes electrical contact with the 
stationary contact 16 before it engages the contact 18. However, the ball 
contact 26 ultimately attains another position, in response to continued 
downward movement of the push button 22, wherein it is in simultaneous 
engagement and electrical contact with all of the stationary contacts, as 
indicated in full lines in FIG. 5 and in broken lines in FIG. 3. The ball 
contact 26 attains the latter "make" position before the push button 22 is fully 
depressed and is restrained against further downward movement by the stationary 
contacts. When the ball contact 26 makes contact with all of the stationary 
contacts, the rod 24 is still within the magnetic influence of the magnet 20 and 
continues to be attracted to the ball contact. As the rod 24 continues to move 
downward and away from the ball contact 26, its influence on the ball contact 
sharply decreases. In the illustrated switch 10 an almost immediate reversal of 
magnetic influence occurs when the rod separates from the ball contact. More 
specifically, as the rod 24 moves out of engagement with and away from the ball 
contact 26, the latter contact comes under the greater influence of the magnet 
20 which causes it to break contact and return to its initial or full line 
position in FIG. 1 before the push button 22 attains its fully depressed or 
broken line position in FIG. 1. 

An increase resistance to the downward movement of the push button or key 22 is 
felt at the instant the ball contact 26 establishes simultaneous electrical 
contact with the stationary contacts 14, 16 and 18 and separates from the rod 
24. Further, a sharp reduction in key stroke pressure is felt at the instant 
that the ball leaves the magnetic influence of the rod 24 and returns to its 
initial position under the magnetic influence of the magnet 20. This tactile 
feedback is highly desirable in a keyboard switch, since it enables a keyboard 
operator to sense when a character has been transmitted by a key. 

The switch 10 provides a single pulse output during each complete switching 
cycle. It will be apparent that after the push button 22 has been depressed a 
sufficient distance to cause the ball contact 26 to make and then break and 
return to its centralized position on the magnet 20, the switch cannot again be 
operated until the push button 22 has returned to its projected position to 
bring the rod 24 into adjacent relation with the ball contact 26 and within the 
magnetic influence of the magnet 20. 

It will be further noted that the switch 10 may be connected in circuit so that 
it is first conditioned to establish two circuit paths through the terminals 
associated with the stationary contacts 14 and 16 and then establish a common 
path to ground through the terminals 18. Thus, the switch may be employed to 
provide simultaneous output at the two terminals 14 and 16. 





<- Previous Patent (MODE SUPPRESSOR FOR ...) | Next Patent (IMPULSE 
TRANSFORMER) ->

Electrical switch - Magsat Corporation - Electrical switch  - United States Patent 3920943 


  

Title:

Electrical switch 


United States Patent 3920943 







Abstract:

A keyboard switch comprises a push button operator supported by a base for 
movement between projected and depressed positions. A contact spring carried by 
the push button operator electrically connects three terminals mounted in fixed 
position on the base when the operator is depressed. The spring cooperates with 
the terminals to provide a second "make" contact which occurs always after a 
first "make" contact. The contact spring also serves to retain the push button 
operator in assembly with the base. In a further embodiment, two contact springs 
carried by a base have free end portions which extend into the path of a push 
button operator supported on the base. Portions of the two contact springs 
define two of three terminals associated with the switch base. A third terminal 
mounted on the base has spaced contact surfaces thereon sequentially engaged by 
free ends of the two contact springs when the push button operator is 
depressed. 


 



Application Number:

05/453723 


Publication Date:

11/18/1975 


Filing Date:

03/22/1974 


Export Citation:

Click for automatic bibliography generation 


Assignee:

Magsat Corporation (West Hartford, CT) 



Primary Class:

200/276.1


Other Classes:

200/276, 200/535 


International Classes:

H01H13/12; H01H41/08; H01H1/24; H01H13/12; H01H41/00; H01H1/12; (IPC1-7): 
H01H13/52; H01H1/26 


Field of Search:

200/159R,159A,276,275,5A 


View Patent Images:

Download PDF 3920943 PDF help


US Patent References:




3808384

PUSHBUTTON KEYBOARD SYSTEM

April 1974

Boulanger




3767878

KEYBOARD SWITCH

October 1973

Sykora




3549846

RELEASABLE FASTENER FOR ACTUATOR ELEMENT OF SNAP SWITCH,OR THE LIKE

December 1970

Francey




3506795

ELECTRICAL SWITCH DEVICE

April 1970

Schmidt




3433914

PUSHBUTTON SWITCH

March 1969

Ericsson




3244847

Manually operated keyboard switch in a stationary mount with guided shaftway

April 1966

Erpel




2567421

Push-button switch

September 1951

Brantingson




2109184

Vehicle signal

February 1938

Sereda







Primary Examiner:

Schaefer, Robert K. 


Assistant Examiner:

Smith, William J. 


Attorney, Agent or Firm:

McCormick, Paulding & Huber 



Claims:

I claim

1. An electrical switch comprising a base member, an operating member supported 
by said base member for movement in one and an opposite direction between one 
and another switching position, contact spring means carried by one of the 
members and having two projecting free end portions, said contact spring means 
engaging said other member when said operating member is in its one switching 
position to maintain said operating member in assembly with said base member, 
means defining three spaced apart electrical terminals mounted in fixed position 
on said base member and having at leat two contact surfaces, said terminals 
being electrically isolated from each other when said operating member is in 
said one switching position, each of said free end portions engaging one of said 
contact surfaces as said operating member is moved in said one direction from 
said one to said other switching position, said contact spring means 
electrically connecting said three terminals when said operating member is in 
said other switching position. 

2. An electrical switch as set forth in claim 1 wherein said contact spring 
means engages said other member when said operating member is in its one 
switching position to maintain said operating member in assembly with said base 
member. 

3. An electrical switch as set forth in claim 1 wherein said contact spring 
means comprises at least one torsion spring having a coil portion and defining 
at least one of said free end portions. 

4. An electrical switch as set forth in claim 1 wherein said contact spring 
means a single torsion spring defining said two free end portions. 

5. An electrical switch as set forth in claim 4 wherein said one member 
comprises said operating member. 

6. An electrical switch as set forth in claim 5 wherein said base member has a 
bore, said operating member comprises a push button operator which has an 
axially elongated shank slidably received in said bore and a recess in said 
shank, and said spring is disposed within said recess. 

7. An electrical switch as set forth in claim 6 wherein said spring includes a 
helically coiled body portion disposed in said recess with its axis genrally 
normal to the axis of said shank and said free end portions project tangentially 
outwardly from said body portion and beyond said shank. 

8. An electrical switch as set forth in claim 7 wherein each of said contact 
surfaces is defined by an associated one of said terminals, said body portion is 
genrally aligned with an associated one of said contact surfaces and each of 
said free end portions is aligned with an associated other of said contact 
surfaces. 

9. An electrical switch as set forth in claim 8 wherein each of said free end 
portions biasingly engages said associated other of said contact surfaces before 
said body portion engages said one conact surface when said push button operator 
is moved from its one to its other switching position. 

10. An electrical switch as set forth in claim 1 wherein said base member 
comprises said one member. 

11. An electrical switch as set forth in claim 10 wherein said contact spring 
means comprises a pair of torsion springs and each of said torsion springs 
defines one of said free end portions. 

12. An electrical switch as set forth in claim 11 wherein each of said torsion 
springs has another end portion which defines an associated one of said 
terminals. 

13. An electrical switch as set forth in claim 12 wherein each of said contact 
surfaces is defined by the other of said three terminals. 

14. An electrical switch as set forth in claim 13 wherein one of said free end 
portions biasingly engages an associated one of said contact surfaces before the 
other of said free end portions engages another of said contact surfaces when 
said operating member is moved from its one to its other switching position. 

15. An electrical switch as set forth in claim 14 wherein said contact surfaces 
comprise two contact surfaces spaced apart in the direction of travel of said 
operating member. 

16. An electrical keyboard switch comprising a base, a push button operator 
supported on said base for movement in one and an opposite direction generally 
toward and away from said base between one and another switching position, means 
for biasing said push button operator to and maintaining it in its one switching 
position, a torsion spring carried by said push button operator and having a 
helically coiled body portion supported with its axis genrally normal to the 
path of push button operator movement and two free end portions projecting 
tangentially outwardly from said body portion, said free end portions engaging 
said push button operator and said base when said operator is in its one 
switching position to maintain said push button operator in assembly with said 
base, three spaced apart electrical terminals mounted in fixed position on said 
base, each of said electrical terminals being electrically isolated from the 
other of said electrical terminals when said push button operator is in its onw 
switching position, each of said terminals having a contact surface thereon, 
said body portion engaging one of said contact surfaces and each of said free 
end portions biasingly engaging an associated other of said contact surfaces 
when said push button operator is in its other switching position to 
electrically connect said electrical terminals. 

17. An electrical keyboard switch as set forth in claim 16 wherein each of said 
other contact surfaces engages an associated one of said free end portions and 
biases it in said opposite direction before said body portion engages said one 
contact surface when said push button operator is moved from its one switching 
postion toward and to its other switching position. 

18. An electrical switch comprising a base member, an operting member supporting 
by said base member for movement in one and an opposite direction between one 
and another switching position, a pair of torsion springs carried by said base 
member, each of said torsion springs having a free end portion, and means 
defining three spaced apart electrical terminals mounted in fixed position on 
said base member, one of said terminals defining two contact surfaces spaced 
apart in the direction of travel of said operating member, each of the other of 
said terminals electrically connected to an associated one of said torsion 
springs, said three terminals being electrically isolated from each other when 
said operating member is in its one switching position, one of said free end 
portions engaging an associated one of said contact surfaces before the other of 
said free end portions engages the other of said contact surfaces when said 
operating member is moved from its one to its other switching position, said 
contact springs electrically connecting said terminals when said operating 
member is in its other switching position. 

19. An electrical switch as set forth in claim 18 wherein said torsion springs 
have said free end portions thereof normally biased toward contacting engagement 
with said contact surfaces and held out of contacting engagement with said 
contact surfaces by said operating member when said operating member is in its 
one switching position and during an initial portion of its travel from said one 
switching position to said other switching position. 

20. An electrical switch as set forth in claim 19 wherein said free end portions 
engage said base member and said operating member when said operating member is 
in said one switching position to retain said operating member in assembly with 
said base member. 

21. An electrical switch as set forth in claim 18 wherein said base member has a 
bore, said operating member comprises a push button operator and has an axially 
elongated shank slidably received in said bore for movement in said one and said 
opposite directions generally toward and away from said base, said shank has a 
recess therein opening through one end thereof and toward said base, said free 
end portions project inwardly through said shank and into said recess and said 
one terminal is mounted on said base in alignment with said recess. 

22. An electrical switch comprising a base member, an operating member supported 
by said base member for movement in one and an opposite direction between one 
and another switching position, contact spring means carried by one of the 
members and having two free end portions projecting in generally opposite 
directions and engaging said other member in said one switching position, and 
means defining three spaced apart electrical terminals mounted in fixed position 
on said base member and having at least two contact surfaces, said terminals 
being electrically isolated from each other when said operating member is in 
said one switching position, each of said free end portions engaging one of said 
contact surfaces as said operating member is moved in said one direction from 
said one to said other switching position, said contact spring means 
electrically connecting said three terminals when said operating member is in 
said other switching position. 

23. An electrical switch as set forth in claim 22 wherein said base member has a 
bore, said operating member comprises a push button operator and has an axially 
elongated shank slidably received in said bore and a recess therein, and said 
free end portions project in generally radial directions through the wall of 
said shank and through the wall of said bore. 

24. An electrical switch as set forth in claim 23 wherein said free end portions 
are normally spring biased into contacting engagement with said contact surfaces 
and held out of contacting engagement with said contact surfaces by said 
operating member in its one switching position and during a portion of its 
travel to its other switching position and including means for biasing said push 
button operator to and maintaining it in its one switching position. 

25. An electrical switch as set forth in claim 24 wherein said biasing means 
comprises a compression spring coaxially surrounding said shank and acting 
between said push button operator and said base member. 

26. An electrical keyboard switch comprising a base member, a push button 
operator supported by said base member for movement in one and an opposite 
direction between projected and depressed positions, means for continuously 
biasing said push button operator toward its projected position, a pair of 
torsion springs mounted on said base member, each of said springs having a free 
end portion projecting into the path of said push button operator, and means 
defining two contact surfaces spaced apart in the direction of travel of said 
push button operator, each of said free end portions aligned with an associated 
one of said contact surfaces and normally spring biased into contacting 
engagement therewith when said push button operator is in its depressed 
position, each of said free end portions held out of contacting engagement with 
its associated contact surface by engagement with said push button operator, 
when said push button operator is in its projected position and during a portion 
of its travel from its projected to its depressed position, each of said free 
end portions exerting biasing force on said push button operator in the 
direction of its depressed position when said push button operator is in its 
projected positions and during only a portion of its travel from its projected 
position to its depressed position, each of said free end portions being out of 
engagement with said push button operator and spring biased into contacting 
engagement with its associated contact surface during the final portion of push 
button operator travel from its projected to its depressed position, one of said 
free end portions engaging its associated contact surface before the other of 
said free end portions engages its associated contact surface when said push 
button operator is moved from its projected position to its depressed position. 

27. An electrical keyboard switch as set forth in claim 26 wherein said free end 
portions cooperate with said base member and said push button operator to retain 
said push button operator in assembly with said base member. 




Description:

BACKGROUND OF THE INVENTION 

This invention relates in general to electrical switches and deals more 
particularly with improved push button switches of double form, momentary 
contact type. The switches of the present invention are particularly adapted for 
use as keyboard switches for electric typewriters, calculators, computers and 
the like, and are particularly suitable for use where a second "make" contact is 
desired which always occurs after a first "make" contact. However, the present 
switches may also be employed where simultaneous double form output is desired. 
The increase demand for low cost electrically operated business machines and 
like apparatus has created need for improved low cost keyboard switches for such 
digital applications. However, a switch suitable for the aforedescribed 
applications must be substantially free of undesirable contact bounce 
characteristics, since the tendency of switch contacts to bounce apart after 
making may result in loss of contact signal and the generation of arcs at the 
contacts which results in electromagnetic interference. 

Accordingly, the general aim of the present invention is to provide improved 
switches of the aforedescribed general type which have a minimal number of 
parts, are of simple durable construction for low cost manufacture and are 
substantially free of undesirable contact bounce characteristics. 

SUUMMARY OF THE INVENTION 

In accordance with the present invention, an improved electrical switch is 
provided which comprises a base member, an operating member supported by the 
base member for movement in one and an opposite direction relative thereto 
between one and another switching position, means defining three electrical 
terminals mounted in fixed position on the base member and having contact 
surfaces, and contact spring means carried by one of the members and having two 
projecting free end portions. The free end portions engage associated contact 
surfaces when the operating member is in its other switching position whereby to 
electrically connect the terminals. The switch may be connected in circuit to 
provide an electrical output at one of the terminals followed by an electrical 
output at another of the terminals or may be arranged to provide simultaneous 
electrical output at two terminals. The contact spring means may also serve to 
retain the operating member in assembled relation with the switch base. 

BRIEF DESCRIPTION OF THE DRAWINGS 

FIG. 1 is an end view of an electrical switch assembly embodying the present 
invention, the push button operator and switch housing being shown in vertical 
axial section. 

FIG. 2 is a fragmentary sectional view taken along the line 2--2 of FIG. 1. 

FIG. 3 is similar to FIG. 1 but shows the push button operator in a depressed 
position. 

FIG. 4 is a fragmentary sectional view taken generally along the line 4--4 of 
FIG. 2. 

FIG. 5 is a fragmentary sectional view taken along the line 5--5 of FIG. 2. 

FIG. 6 is an end view of another electrical switch assembly embodying the 
present invention, the push button operator and switch housing being shown in 
vertical axial section. 

FIG. 7 is a fragmentary sectional view taken generally along the line 7--7 of 
FIG. 6. 

FIG. 8 is a fragmentary side elevational view of the switch of FIG. 6, a portion 
of the housing side wall shown broken away to reveal structure therebehind. 

FIG. 9 is a fragmentary sectional view taken along the line 9--9 of FIG. 7. 

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 

Turning now to the drawings, and referring first to FIGS. 1-5, a fragmentary 
portion of a keyboard switch assembly is shown which includes a push button 
switch module embodying the present invention and indicated generally by the 
reference numeral 10. The illustrated switch module 10 is of a double form, 
momentary contact type, and comprises a part of the keyboard switch assembly 
which includes a plurality of switch modules integrally connected in 
side-by-side series and particularly adapted for use in the keyboard for a 
computer, electric typewriter or the like. It includes a base, indicated 
generally at 12, which has three spaced apart electrical terminals 14, 16 and 18 
mounted in fixed position thereon, and further includes an operating member or 
push button operator, indicated generally at 20. The push button operator is 
supported on a base for movement in one and an opposite direction relative 
thereto between projected and depressed positions corresponding to one and 
another switching position. A contact spring indicated generally at 22 and 
carried by the push button operator 20 has two projecting free end portions. 
Each of the spring free end portions engages a contact surface on one of the 
electrical terminals when the push button operator is in its depressed position 
to provide electrical connection between the three terminals 14, 16 and 18 as 
will be hereinafter further discussed. The free end portions of the spring 22 
also cooperate with the base 12 and the push button operator 20 to retain the 
latter two parts in assembled relation, as will be hereinafter further 
discussed. Another spring 24 acts between the push button operator 20 and the 
base 12 to continuously urge the operator toward its projected position. 

The base 12 may, as shown, form a common base for a plurality of integrally 
connected switch modules and comprises a hollow housing 26 and a terminal board 
28 secured thereto by suitable fasteners such as the fastener 30. The housing 26 
is made from an electrical insulating material and is preferably molded from 
plastic or like material. Further considering an individual switch module 10, 
the housing 26 thereof has a generally cylindrical neck portion at its upper end 
which partially defines a bore 32 of rectangular cross-section which extends 
downwardly therethrough. A pair of downwardly opening recesses 34, 34 are formed 
in the lower portion of the housing 26 at opposite sides of the housing bore. 
Each recess 34 is separated from the bore 32 by a dividing wall which has a 
downwardly opening slot 35 formed therein. Thus, each slot 35 communicates 
between an associated recess 34 and the bore 32 as best shown in FIGS. 2 and 3. 
The terminal board 28 comprises a generally rectangular strip of electrical pg,6 
insulating material common to the various switch modules 10, 10 which comprise 
the keyboard assembly and provides closures for the housings thereof. The 
electrical terminals 14, 16 and 18 are mounted in fixed position on the terminal 
board 28 and have terminal portions which extend downwardly therethrough for 
connection to an external circuit network or, if desired, to a printed circuit 
associated with either side of the terminal board. The terminals 14, 16 and 18 
respectively define upwardly facing contact surfaces 36, 38 and 40. The contact 
surfaces 36 and 38 are respectively disposed within associated recesses 34, 34 
whereas the contact surface 40 associated with the central terminal 18 is 
disposed centrally within the bore 32. 

The push button operator 20 has a button portion 42 at its upper end and an 
axially elongated shank portion 44 which depends from the button portion and has 
a generally rectangular cross-sectional configuration to complement the 
cross-sectional configuration of the bore 32 in which it is slidably received. 
At its lower end, the shank 44 has a downwardly opening recess 46 to receive the 
spring 22 therein. Four downwardly opening bayonet slots 48, 48 are formed in 
the walls of the shank 44 which surround the recess 46. 

The spring 24 comprises a compression spring which surrounds the cylindrical 
neck portion of the housing 26 and acts between the housing and the button 
portion 42 to urge the push button operator 20 upwardly toward its projected 
position as it appears in FIG. 1. The spring 22 retains the push button operator 
20 in assembly with the base member 12 and also limits the travel of the push 
button operator relative to the base member 12, as will be hereinafter further 
discussed. 

Considering now the spring 22 in further detail, it comprises a torsion spring 
which has a helically coiled body portion 50 and a pair of free end portions 52 
and 54 which project tangentially outwardly in opposite directions from opposite 
ends of the helical body portion. The spring 22 is assembled with the push 
button operator 20 and a base member 12 after the compression spring 24 has been 
positioned on the neck of the housing 26 and the shank 44 has been inserted into 
the bore 32. The body portion 50 is positioned within the recess 46 and 
thereafter the free end portions 52 and 54 are deflected laterally inwardly or 
toward each other to facilitate entry into a pair of generally diametrically 
opposed bayonet slots 48, 48. Each free end portion is also disposed within an 
associated slot 35. The free end portions 52 and 54 cooperate with the bayonet 
slots to retain the spring 22 in assembly with the push button operator 20, as 
best shown in FIG. 5. Each of the free end portions 52 and 54 extend outwardly 
through an associated slot 35 in the housing 26 and into an associated recess 
34. When the push button operator 20 is in its projected position, as it appears 
in FIGS. 1 and 4, it will be noted that each of the free end portion of the 
spring 22 engages the upper edge of the associated slot 35 and the lower edge of 
an associated bayonet slot 48 to limit the upward travel of the operator 20 and 
to retain it in assembly with the base member 12. 

The switch assembly is completed by securing the terminal board 28 in assembly 
with the housing 26 with fasteners 30, 30. When the switch 10 is fully 
assembled, each free end portion of the spring 22 is positioned above and in 
general alignment with an associated contact surface defined by one of the 
electrical terminals. Thus, the free end portion 52 is positioned above and 
generally aligned with the contact 36 whereas the free end portion 54 is 
positioned above and aligned in like manner with the contact 38, as best shown 
in FIGS. 1 and 2. It should be further noted that the central contact surface 40 
on the terminal 18 is positioned below and aligned with the spring body portion 
50. 

Considering now the operation of the switch 10 and referring first particularly 
to FIG. 1, when the push button operator 20 is depressed, the free end portions 
52 and 54 respectfully engage the contact surfaces 36 and 38 before the body 
portion 50 engages the contact surface 40, a partially depressed position of the 
push button operator 20 being indicated in broken lines. When the operator 20 
attains its fully depressed position, as it appears in FIG. 3, the body portion 
50 engages the contact surface 40 to establish electrical connection between the 
contacts 14, 16 and 18. The switch 10 may be connected in circuit so that it is 
first conditioned to establish two circuit paths through the terminals 14 and 16 
and then establish a common path to ground through the terminal 18. Thus, the 
switch may be employed to provide simultaneous output at the two terminals 14 
and 16. The switch 10 may also be arranged in an external circuit network to 
complete a first circuit associated with the terminal 14 and 16 when the push 
button operator 20 is in a partially depressed position, as it appears in broken 
lines in FIG. 1, and to complete a second circuit which includes the central 
terminal 18 and either or both the terminals 14 and 16 when the operator is 
fully depressed, as it appears in FIG. 3. 

The legs 52 and 54 are carried or lowered into initial engagement with the 
respectively associated contact surfaces 36 and 38 by the downward movement of 
the push button actuator 20, the initial position of contact spring engagement 
being indicated by broken lines in FIG. 1. Thereafter, further downward pressure 
on the push button operator causes the contact surface 36 to exert a generally 
upward or clockwise biasing force on the leg 52 and the contact surface 38 to 
exert a generally upward or counterclockwise biasing force on the leg 54, as 
will be evident from reference to FIGS. 1 and 3. This arrangement substantially 
eliminates any tendency for the spring end portions 52 and 54 to bounce with 
respect to the contact surfaces 36 and 38 after making. Accordingly, the present 
switch is substantially free of contact bounce characteristics which renders it 
particularly suitable for use as a keyboard switch where a sharp digital signal 
is required. 

Referring now to FIGS. 6-9, another switch assembly embodying the present 
invention includes a push button switch module indicated generally by the 
reference numeral 10a. The switch 10a is similar in some respects to the switch 
10 previously described and parts similar to parts previously described bear the 
same reference numeral and a letter a suffix and will not be described in 
detail. 

The switch 10a has a base 12a which includes a hollow housing 26a and a terminal 
board 28a secured thereto by fasteners, such as the fastener 30a. It further 
includes a push button operator 20a and a compression spring 24a which urges the 
operator 20a toward its projected position. The base 12a differs from the base 
12 previously described in that it has a somewhat lower profile. The slots 35a, 
35a are also of a slightly different configuration than the slots 35 of the 
previously described base. The push button operator 20a includes a button 
portion 42a and a hollow axially elongated shank 44a which has a generally 
rectangular cross section to complement the cross section of the housing bore 
32a. The shank 44a has openings 48a, 48a through opposite walls thereof which 
communicate with its hollow interior. 

The principal differences between the switch 10a and the previously described 
switch 10 reside in the construction and arrangement of the contact springs and 
electrical terminals. The switch 10a includes a pair of contact springs 
indicated generally at 56, 56'. Each contact of the springs 56, 56' comprise a 
torsion spring and each spring respectively includes a helically coiled body 
portion 58, 58' and a pair of free end portions or legs 60, 60' and 62, 62'. The 
latter legs project tangentially outwardly from opposite ends of the body 
portion in generally parallel relation as best shown in FIG. 6. The lower leg of 
each spring 56' is bent to form an electrical terminal, the terminals so formed 
being designated at 62, 62'. Each spring 56, 56' is supported in an associated 
recess 34a by an elongated cylindrical rod 64 which extends through the spring 
body and has its ends supported in opposite end walls of the housing 26a as best 
shown in FIG. 7. The switch 10a also includes a third or central terminal 66 
mounted in fixed position on the terminal board 28a. At its upper end the 
terminal 66 has two axially spaced apart upwardly facing contact surfaces 68 and 
70 disposed within the bore 32a. 

As in the previously described structure, the push button operator 20a is 
retained in assembly with the base 12a by contact spring free end portions 60 
and 60'. Each of the latter free end portions projects inwardly from an 
associated recess 34a through an associates slot 35a and into and through an 
associated opening 48a in the shank. Thus, when the push button operator 20a is 
in its projected position as it appears in full lines in FIG. 6 and in FIG. 8 
and 9, each free end portion respectively engages the upper edge of an 
associated slot 35a and the lower edge of an associated opening 48a, as best 
shown in FIG. 9 to retain the push button operator 20a in assembly with the base 
member 12a. The springs 56, 56' are wound so that each of the legs 60 and 60' is 
normally biased in the direction if its broken line position of FIG. 6. More 
specifically the spring leg 60 is biased in a clockwise direction and toward 
engagement with the contact surface 68 whereas the spring leg 60' is biased in a 
counterclockwise direction and toward engagement with the contact surface 70. 
However, the upwardly directed force exerted by the compression spring 24a upon 
the push button operator 20a exceeds the combined downwardly directed force 
exerted upon the operator 20a by the spring legs 60, 60'. Therefore, the push 
button operator 20a is normally maintained in its projected or full line 
position of FIG. 1 and holds the spring legs 60, 60' out of engagement with the 
contact surfaces 68 and 70, respectively. 

Considering now the operation of the switch 10a, when the push button operator 
20a is depressed, the contact spring end portions 60 and 60' are lowered into 
engagement with the contact surfaces 68 and 70 respectively. Since the contact 
surface 68 is spaced above a contact surface 70, the leg 60 will engage or 
"make" with the contact surface 68 before the leg 60' engages the contact 
surface 70. Thus, circuit continuity is first established between electrical 
terminals 62 and 66. A second "make" contact occurs when the spring leg 60' 
engages the contact surface 70 and at this time each of the terminals 62, 62' 
and 66 are electrically connected. Thus, it will be apparent that the switch may 
be connected in a circuit network to provide a second "make" contact which 
occurs always after a first "make" contact occurs or, if desired, the switch may 
be arranged to provide simultaneous electrical output at the terminals 62 and 66 
if the terminal 62' is connected to a common ground, as previously discussed 
with reference to the switch 10. As in the previously described switch structure 
10, the contact springs 56, 56' are constructed and arranged so that the free 
end portions 60 and 60' thereof exert downwardly directed biasing force on the 
push button operator 20a when it is in its fully projected position and during 
at least a portion of its travel between its projected and depressed positions. 
Since the end portions 60 and 60' are lowered into contact engagement with the 
contact surfaces 68 and 70 by depressing the push button operator 20a, the 
tendency for the movable contacts 60 and 60' to bounce after "making" with the 
contact surfaces 68 and 70 is substantially wholly eliminated.