US3857000A

US3857000A - Multi-position slide switch assembly with housing means holding common conductive rail in fixed abutting relationship with end terminals of fixed contact array

Info

Publication number: US3857000A
Application number: US00376638A
Authority: US
Inventors: H Boulanger
Original assignee: Texas Instruments Inc
Current assignee: Texas Instruments Inc
Priority date: 1973-07-05
Filing date: 1973-07-05
Publication date: 1974-12-24
Anticipated expiration: 1991-12-24
Also published as: DE2432317A1; IT1016302B; AU7027374A; FR2236265A1; GB1470225A; DD114880A5; ES427957A1; BR7405521D0; JPS5048472A; DK359974A; RO70448A; NL7408598A

Abstract

A desktop keyboard for data encoders, calculators and the like comprises an electrically insulative board having a plurality of contact members and mounting clusters of key switches to provide electrical engagement between pairs of contact members. A plurality of multiposition point switches are also mounted on the board and comprise a contact element slidably movable to any one of a plurality of contact members to provide a selected mode of operation. An electrically conductive retainer plate is held in fixed abutting relationship with the outermost printed circuit board fixed contacts by means of attachment of the housing to the printed circuit board. The contact element is retained in each mode of operation by indexing means and is continuously electrically connected with the retainer plate.

Description

United States Patent [191 Boulanger Dec. 24, 1974 [75] Inventor: Henry J. Boulanger, Cumberland,

[73] Assignee: Texas Instruments Incorporated,

Dallas, Tex.

[22] Filed: July 5, 1973 21 Appl. No: 376,638

[52] US. Cl 200/16 D, 200/257, 200/252 [51] Int. Cl. H0lh 15/06 [58] Field of Search 200/5 R, 5 A, 16 C, 16 D,

Davis 200/16 D Dapot et al. 200/5 R Primary Examiner-James R. Scott Attorney, Agent, or Firm-lohn A. Haug; James P. McAndrews [57] ABSTRACT A desktop keyboard for data encoders, calculators and the like comprises an electrically insulative board having a plurality of contact members and mounting clusters of key switches to provide electrical engagement between pairs of contact members. A plurality of multiposition point switches are also mounted on the board and comprise a contact element slidably movable to any one of a plurality of contact members to provide a selected mode of operation. An electrically conductive retainer plate is held in fixed abutting relationship with the outermost printed circuit board fixed contacts by means of attachment of the housing to the printed circuit board. The contact element is retained in each mode of operation by indexing means and is continuously electrically connected with the retainer plate.

11 Claims, 7 Drawing Figures PATENTED 3,857. 000

sum 3 OF a MULTI-POSITION SLIDE SWITCH ASSEMBLY WITH HOUSING MEANS HOLDING COMMON CONDUCTIVE RAIL IN FIXED ABUTTING RELATIONSHIP WITH END TERMINALS F FIXED CONTACT ARRAY This application contains subject matter similar to that disclosed in coassigned, copending applications Ser. No. 376,779 entitled Key Switch Apparatus filed July 5, 1973 and Ser. No. 376,654 entitled Key Switch Apparatus filed July 5, 1973.

This invention relates to keyboards and more particularly to keyboards having multiposition switches.

In many types of apparatus, such as desk top calculators it is desired to provide a selection of any one of a plurality of modes of operation. For instance it may be desirable to provide a selection among a floating decimal, or fixed decimal at the 0, l, 2, 4 or 6 integer. It also may be desirable to provide a selection among different rounding operations, that is, rounding up, rounding off or rounding down.

Thus it is an object of the invention to provide a multiposition point switch which is reliable, long-lived, inexpensive to produce and well adapted to mass manufacturing techiques to keep the labor content to a minimum.

Still further objects and advantages of the invention will be apparent from the following detailed description and claims and from the accompanying drawings illustrative of the invention wherein:

FIG. 1 is a perspective view of a keyboard device including a plurality of key switch clusters and a plurality of multiposition point switches which are mounted on a printed circuit board;

FIG. 2 is a cross sectional view taken on lines 2-2 of FIG. 1 showing a key switch in its normally open or contacts disengaged position;

FIG. 3 is a cross sectional view similar to FIG. 2 but showing the key switch in its closed or contacts engaged position;

FIG. 4 is a perspective view of a movable bridge member used in the key switches of FIGS. 1-3;

FIG. 5 is a cross section taken through a portion of the printed circuit board showing a contact member;

FIG. 6 is a cross sectional plan view taken on lines 66 of FIG. 1 through multiposition point switch 6; and

FIG. 7 is a perspective view of the contact arrangement of the multiposition switch of FIG. 6.

In the detailed description, corresponding reference characters indicate corresponding elements throughout the several views of the drawings.

Briefly, in accordance with the invention an electrically insulative board has a printed circuit disposed on one surface and a plurality of staple like U-shaped members inserted through apertures from the opposed surface with the free ends of the staples terminating in electrical engagement with selected portions of the printed circuit. A plurality of multiposition point switches are disposed on the circuit board adapted to make electrical engagement between a first and any other one of a row of staples. A transversely slidable member has a plurality of detents formed on a surface thereof. A spring biased spherical member is urged into a detent as the detent comes into alignment with the spherical member as the member is moved to give a plurality of stable positions to the slide member. A

contact retainer extends across the row of staples and is in fixed electrical connection with the first staple of the row. A leg depends from the slide member and captures a resilient contact between the retainer and the board and is slidable with the slide member so that at any of the stable positions the resilient contact is in electrical engagement with another one of the row of staples and the retainer.

FIG. I shows a Keyboard I particularly useful in desktop calculator models. As seen in the Figure there are a plurality of key clusters 2-5 and a plurality of multiposition point switches 6-8 all of which are mounted on a circuit board 16. Although any conventional circuit board including two sided boards may be employed it is preferred to use a board having desired circuitry printed on one side, the bottom side as viewed in FIG. I with the required contacts in the form of staple like members disposed on the opposite side of the board with the legs of the staples extending through apertures in the board and terminating in electrical connection with selected portions of the printed circuit. It will be realized of course that various other contact I members could be employed.

The several key clusters are identical in construction, the only difference being the number of keys and the size of the particular buttons in each cluster. Thus a detailed discussion of one switch will suffice for the others. Key cluster 3 comprises a housing 14 of a conventional electrically insulative material such as polycarbonate mounted on board 16 in any convenient manner as by use of conventional screw fasteners (not shown). A plurality of key units 12 are formed in housing 14, each unit having a guideway 26 shown in FIGS. 2 and 3. For each key unit 12 a pair of U-shaped electrically conductive contact members are in the form of

staples

18, 20 are received in apertures provided in electrically insulative board 16 extending from a first surface 22 to a second opposed surface 24. An elongated keybody 28 I also of electrically insulative material is slidingly received in guideway 26 and is adapted for movement toward and away from

staples

18, 20. Keybody 28 is formed with an axially extending slot 30 in communication with a spring receiving bore 32 at the force transmitting end 34 of keybody 28.

An electrically conductive movable bridge member 36, a relatively stiff, inflexible member is disposed in a switch chamber 56 within key unit 14. As best seen in FIG. 4, member 36 has two

contact sections

38 and 40 with a leg 42 extending from contact section 40 and terminating at a first distal end 44. A second leg 46 extends from contact section 38 and has a second distal end 48.

Intermediate contact sections

38 and 40 is an upwardly bent portion 50.

Movable bridge member 36 is disposed in a switch chamber with contact section 38 in engagement with bight 52 of staple 20. A helical coil spring member 58 is also disposed in switch chamber 56 and extends from a spring seat 60 formed by the intersection of slot 30 and .bore 32 in keybody 28 to the movable contact member 36 with the second leg 46 and upwardly bent portion 50 extending into the space defined by spring 58 forming a seat for the spring.

Leg 46 cooperates with portion 50 to maintain spring 58 in the desired location. Distal end 48 of leg 46 is provided with a hook portion to facilitate assembly of the device. That is, spring 58 can be placed on movable contact member 36 with distal end 48 hooked over the 3 top of the spring maintaining the spring slightly compressed and holding it in position so that it can'be easily handled. Once mounted in the switch distal end 48 is no longer functional since seat 60 of keybody 28 further compresses spring 58 and maintains it away from end 48.

Keybody 28 is formed with a laterally projecting U- shaped portion 62 formed by legs 64 (only one being shown) integrally attached to keybody 28 and joined by a bight portion 66. A beveled surface 68 is formed in bight portion 66 which is adapted to engage distal end 44 of leg 42 of movable contact member 36 which is trained through the opening in U-shaped portion 62.

As seen in FIG. 2 in which the switch is at the at rest contacts disengaged position, spring 58 reacts against bight 52 and the wall of housing 14 through the extreme end portion 70 of contact section 38 and biases keybody 28 upwardly with bight portion 66 camming leg 42 upwardly lifting contact section 40 out of engagement with bight 54 of staple 18. As the keybody 28 is depressed by a force transmitted through the force transmitting end 72 of keybody the cam 66 is moved downwardly allowing leg 42 and contact section 40 to move downwardly until contact portion 40 comes into engagement with bight 54 of staple 18. Use of the single spring 58 as shown provides both pretravel and overtravel of the keybody. It will also be noted that all of the spring force is directly utilized as contact force.

In an exemplary switch made in accordance with the invention the keybody has approximately 0.150 inches overall travel. Contact engagement occurs after approximately 0.075 inches followed by 0.075 inches overtravel with surface 66 moving away from distal end 44 and spring 58 being further compressed. While bridge member 36 is pivoting on bight portion 52 of staple there is a slight contact wiping occurring at that section since end 70 forces bridge member 36 to slide slightly to the left as seen in FIGS. 2 and 3, upon contact engagement. However, once contact section 40 comes into engagement with bight 54 there is no further sliding movement and hence no electrical noise after contact engagement.

Multiposition point switches 6, 7 and 8 shown in FIG. 1 are of identical construction and hence only one will be discussed in detail. In FIG. 6 a multiposition point switch is illustrated. The switch is shown having six positions, however the particular number of positions is a matter of choice. Housing 80 mounts a slide member 82 thereon and is formed with opposed lips 84 to confine slide 82 to linear sliding movement (right and left as seen in FIG. 6). Integrally formed with slide member 82 is a knob 86 extending from a raised platform 88 on which a series of serrations 90 is preferably provided to facilitate handling. A series of detents 92 are formed in the bottom surface of slide 82 each being adapted to receive therein a spherical member 94 received in bore 96 formed in housing 80 and biased toward the slide member by a coil spring 98 disposed in bore 96 intermediate member 94 and a bottom wall of the bore forming a spring seat 100.

Grooves 102, 104 are formed on opposite sides of housing 80 on the end of the housing received on printed circuit board 16 and receive therein respective opposite ends 106, 108 of an electrically conductive retainer plate 110. A bore 112 is formed in slide member 82 and lockingly receives the shank 114 of leg 116 depending from slide member 82 to mount leg 116 in housing 80. Leg 116 extends through a longitudinally extending slot 118 formed in plate and is received in a slot 120 of a resilient electrically conductive member 122. Resilient member 122 so that sliding movement of slide member 82 causes concomitant sliding movement of resilient conductive member 122 is generally wave shaped having, an undulated convex and and concave top and bottom surface. A row of contact members such as staples 126 between outer contact members such as

staples

128 and 130 are disposed beneath retainer plate 110 and are arranged so that their bight portions are generally parallel to one another. The legs of staples 126 extend through apertures in board 16 in the same manner as shown in FIG. 5 with at least one leg of staples 126 in electrical connection with a selected portion of the printed circuit. The

outer staples

128 and 130 of the row are electrically connected to ends 106, 108 respectively of the retainer plate, however only staple 128 is in electrical connection with the printed circuit. Thus a circuit path can be traced from the printed circuit through staple 128, plate 110, spring contact member 122 to one of the staples 126 depending on the position of slide member 82. The indents 92 are so located relative to the position of staples 126 that when spherical member 94 is received in any one of detents 92 spring contact 122 is biased into electrical contact with one of staples 126.

Housing 82 may be mounted on board 16 in any convenient manner such as by use of screws 132. A duplicate set of detents 134, extend from the center of slide 82 to the right as seen in FIG. 6 so that spherical member 94 and spring 98 can be located either as shown or in bore 136 if so desired.

The design of the keyboard described above is particularly suitable for mass manufacturing techniques. The printed circuit is plated on a surface thereof, the electrical contacts in the form of staples are inserted through apertures provided in the board, the connections are soldered by flow soldering and then the entire board is scrubbed clean with appropriate detergents. The board acts as a support for the several key clusters and multiposition switches which are locked into place, as mentioned supra, as by use of screw fasteners. No jumpers or other connectors are required so that hand work on the keyboard is kept to an absolute minimum. Once the keyboard is assembled with its switches thereon it is placed in a receiving bezel of a desk top calculator and the circuit board is electrically connected to the other component parts of the apparatus such as for instance a read only memory (ROM), program counter (PC), instruction register (IR), control decoders, and other desired components.

Although the invention has been described with respect to specific preferred embodiments thereof, many variations and modifications will immediately become apparent to those skilled in the art. It is therefore the intention that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.

I claim:

1. A multiposition switch comprising a base, a plurality of stationary contacts mounted on the base electrically separated from one another and arranged in a row, a housing mounted on the base over the row of stationary contacts, a slide member, means for slidably mounting the slide member on the housing, the slide member slidable to and from a plurality of stable positions, an electrically conductive retainer mounted in the housing and electrically connected to one of the contacts in the row, a movable contact member disposed in the housing, the movable contact member in continuous electrical connection with the electrically conductive retainer, means operatively connecting the movable contact member with the slide member for movement therewith, the movable contact member being in electrical engagement with another respective stationary contact when the slide member is in each of its stable positions.

2. A multiposition switch according to claim 1 in which a row of detents is formed in a surface of the slide member and movable spring biased retaining means is mounted in the housing and is aligned with the row of detents so that the retaining means moves into each detent upon presentation of each detent to the retaining means.

3. A multiposition switch according to claim 1 in which the electrically conductive contact retainer is disposed over the row of stationary contacts and the movable contact member is resilient and is located intermediate the contact retainer and the row of stationary contacts.

4. A multiposition switch comprising a base, a plurality of stationary contacts mounted on the base electrically separated from one another and arranged in a row, a housing mounted on the base over the row of stationary contacts, a slide memberslidably mounted on the housing, the slide member slidable to and from a plurality of stable positions, an electrically conductive contact retainer disposed in the housing, the contact retainer being an elongated plate having an L shaped portion at each end, each L-shaped portion comprising first and second legs, the first leg supporting the plate and the second leg spacing the plate above the base, a movable contact member disposed in the housing, the movable contact member in continuous electrical connection with the electrically conductive retainer, means mounted in the housing operatively connecting the movable contact member with the slide member for movement therewith, the movable contact member being in electrical engagement with a respective stationary contact when the slide member is in each of its stable positions.

5. A multiposition switch according to claim 4 in which a longitudinally extending slot is formed in the elongated plate and the means operatively connecting the movable contact member with the slide member includes a leg depending from the slide member through the slot and terminating at the movable contact.

6. A multiposition switch according to claim 4 in which the movable contact has two convex undulated surfaces joined by a concave undulated surface, the convex undulations in wiping contact with the contact retainer plate, the bottom surface of the concave undulation adapted to engage the row of stationary contacts,

and a slot is formed in the retainer plate through which extends the leg depending from the slide member.

7. A multiposition switch according to claim 6 in which the base comprises an electrically insulative board having first and second opposed surfaces, two rows of apertures extend from the first to the second surface, the row of stationary contacts comprises electrically conductive staple elements having a bight portion connecting legs, the legs received in respective apertures.

8. A multiposition switch according to claim 7 in which a printed circuit is disposed on the second surface of the base and the legs of the staples terminate in electrical connection with selected portions of the circuit.

9. A multiposition point switch comprising a housing, an electrically insulative board having first and second opposed surfaces, a row of pairs of apertures extending from the first to the second surfaces, a printed circuit formed on thelsecond surface, electrically conductive U-shaped contact elements having a bight portion joining two legs, the legs of the Ushaped element received in respective pairs of apertures, at least certain ones of the legs terminating in electrical connection with selected portions of the printed circuit, a movable contact retainer plate disposed in the housing having a tab portion at two opposite ends, means for mounting the retainer plate so that the tab portions are received on the bight of the two extreme U-shaped contact elements of the row, a portion of the movable contact retainer plate intermediate the tabs being spaced above the bights of the remainder of the U-shaped contact elements of the row, a resilient movable generally wave shaped contact plate disposed intermediate the retainer plate and the board in wiping contact with the retainer plate and the board, the movable contact plate adapted to engage any single selected bight of the said remainder of the U-shaped contact elements, and means mounted in the housing to move the movable contact plate to any selected bight of the said remainder of the U-shaped contact element, one of the said extreme U- shaped contact elements of the row being in electrical connection with the printed circuit.

10. A multiposition switch according to claim 9 in which the means for moving the movable contact includes a slide member mounted in the housing, a leg depending from the slide member connected to the movable contact plate for movement therewith, and in dexing means to indicate the position of the slide when the movable contact plate is in electrical engagement with a selected bight of the said remainder of Ushaped contact elements of the row.

1111. A multiposition switch according to claim 10 in which the indexing means also includes movable retaining means to render a plurality of stable positions of the slide member.

Claims

4. A multiposition switch comprising a base, a plurality of stationary contacts mounted on the base electrically separated from one another and arranged in a row, a housing mounted on the base over the row of stationary contacts, a slide member slidably mounted on the housing, the slide member slidable to and from a plurality of stable positions, an electrically conductive contact retainer disposed in the housing, the contact retainer being an elongated plate having an L-shaped portion at each end, each L-shaped portion comprising first and second legs, the first leg supporting the plate and the second leg spacing the plate above the base, a movable contact member disposed in the housing, the movable contact member in continuous electrical connection with the electrically conductive retainer, means mounted in the housing operatively connecting the movable contact member with the slide member for movement therewith, the movable contact member being in electrical engagement with a respective stationary contact when the slide member is in each of its stable positions.

6. A multiposition switch according to claim 4 in which the movable contact has two convex undulated surfaces joined by a concave undulated surface, the convex undulations in wiping contact with the contact retainer plate, the bottom surface of the concave undulation adapted to engage the row of stationary contacts, and a slot is formed in the retainer plate through which extends the leg depending from the slide member.

9. A multiposition point switch comprising a housing, an electrically insulative board having first and second opposed surfaces, a row of pairs of apertures extending from the first to the second surfaces, a printed circuit formed on the second surface, electrically conductive U-shaped contact elements having a bight portion joining two legs, the legs of the U-shaped element received in respective pairs of apertures, at least certain ones of the legs terminating in electrical connection with selected portions of the printed circuit, a movable contact retainer plate disposed in the housing having a tab portion at two opposite ends, means for mounting the retainer plate so that the tab portions are received on the bight of the two extreme U-shaped contact elements of the row, a portion of the movable contact retainer plate intermediate the tabs being spaced above the bights of the remainder of the U-shaped contact elements of the row, a resilient movable generally wave shaped contact plate disposed intermediate the retainer plate and the board in wiping contact with the retainer plate and the board, the movable contact plate adapted to engage any single selected bight of the said remainder of the U-shAped contact elements, and means mounted in the housing to move the movable contact plate to any selected bight of the said remainder of the U-shaped contact element, one of the said extreme U-shaped contact elements of the row being in electrical connection with the printed circuit.

10. A multiposition switch according to claim 9 in which the means for moving the movable contact includes a slide member mounted in the housing, a leg depending from the slide member connected to the movable contact plate for movement therewith, and indexing means to indicate the position of the slide when the movable contact plate is in electrical engagement with a selected bight of the said remainder of U-shaped contact elements of the row.

11. A multiposition switch according to claim 10 in which the indexing means also includes movable retaining means to render a plurality of stable positions of the slide member.