US3582578A

US3582578A - Coordinate selector switch with tape indicator and cover

Info

Publication number: US3582578A
Application number: US803223*A
Authority: US
Inventors: Joseph Larue Lockard
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1969-02-28
Filing date: 1969-02-28
Publication date: 1971-06-01
Anticipated expiration: 1988-06-01
Also published as: NL141692B; BE746600A; DE2008020B2; CH497780A; GB1247314A; FR2033166A5; SE368475B; JPS5023145B1; DE2008020A1; AT303877B; NL7002416A; NO129427B

Abstract

An selector switch is disclosed which features conductive strips mounted on interior surfaces of spaced insulating boards. The strips are oriented in crossing relationship and a contact spring is slidably mounted between the boards so as to selectively contact a pair of crossing strips to provide an interconnection. The top board includes slots which define contact spring travel and allow a spring mounting element to extend above the top board for manipulation. A thin plastic grid is mounted over the lower board which serves a dual function by preventing conductive material of the strips thereon from being smeared to create a short between strips and also by providing an indexing action for each contact spring. The spring mounting elements are connected to thin flexible plastic tapes which follow the mounting elements in movement and cover the guide slots to minimize entry of foreign particles. Numerals printed on the tape are displayed through a window in the top board to provide symbolic indication of spring contact position.

Description

United States Patent [72] Inventor Joseph Larue Lockard Harrisburg, Pa. [21] Appl. No. 803,223 [22] Filed Feb. 28, 1969 [45] Patented June 1, 1971 [73] Assignee AMP Incorporated Harrisburg, Pa.

[54] COORDINATE SELECTOR SWITCH WITH TAPE INDICATOR AND COVER 9 Claims, 10 Drawing Figs.

[52] U.S. Cl 200/16, 200/166, 200/18 [511 Int.Cl ...H0lh 15/00 [50] Field of Search ..200/l6, 166 (SD),l7.l8,l59(B),86

[56] References Cited 7 UNITED STATES PATENTS 2,899,676 8/1959 Rivers et al. 200/16X 3,027,506 3/1962 Stenhammar et al. 200/16UX 3,146,320 8/1964 Wang et a1 ZOO/16X 3,193,630 7/1965 Shlesinger, Ir. 200/ l 6 3,308,250 3/1967 Field 111 et a1 200/16 3,308,253 3/1967 Krakinowski ZOO/86X 3,382,338 5/1968 Arseneault et a1 ZOO/159(8) 3,495,052 2/1970 Tauscher ZOO/16X ABSTRACT: An selector switch is disclosed which features conductive strips mounted on interior surfaces of spaced insulating boards. The strips are oriented in crossing relationship and a contact spring is slidably mounted between the boards so as to selectively contact a pair of crossing strips to provide an interconnection. The top board includes slots which define contact spring travel and allow a spring mounting element to extend above the top board for manipulation. A thin plastic grid is mounted over the lower board which serves a dual function by preventing conductive material of the strips thereon from being smeared to create a short between strips and also by providing an indexing action for each contact spring. The spring. mounting elements are connected to this flexible plastic tapes which follow the mounting elements in movement and cover the guide slots to minimize entry of foreign particles. Numerals printed on the tape are displayed through a window in the op board to provide symbolic indication of spring contact position.

IOO

PATENTED JUN 1 I97! SHEET 1 OF 4 INVENTOR. Joseph Lurua Lockord BY /MAf/Mw Y PATENTED JUN 1 |97| SHEET 2 OF 4 Vi F MEI

INVENTOR. Joseph Lorue Lockord PATENTED JUN nan 'SHEEI 3 OF 4 INVENTOR. Joseph Larue Lockord BY SHEET U 0F 4 PATENTED JUN 1 l9?! INVENTOR. Joseph Larue Lockurd COORDINATE SELECTOR SWITCH WITH TAPE INDICATOR AND COVER BACKGROUND OF THE INVENTION Coordinate slide selector switches are well known in the switch art. U.S. Pat. No. 3,205,319 to F. M. Anderson, et al. granted Sept. 7, I965, evidences an example of the crossbar slide selector switch which employs a contact spring caused to wipe across conductive printed circuit paths on an insulating board. U.S. Pat. 2,927,985 to G. D. Rivers granted Mar. 8, I960, shows a similar arrangement having a relay drive to ef fect contact selection. Still another variation of a multiple slide switch which includes a visual indication of switch position is shown in U.S. Pat. No. 3,146,320 to An Wang et al. granted Aug. 25, 1964.

In general, slide switches of the prior art are required to have a certain minimum size based upon that spacing between conductive strips necessary to assure electrical isolation from one strip to another. One of the reasons for this is that in a slide-type switch a spring member is repeatedly driven across the conductive strips under a pressure sufficient to remove and wipe small amounts of conductive material across the insulating material between the strips. Eventually this may cause a short circuit between strips and failure of the switch device. As a second problem, slide switches in general require some indexing mechanism so that the slide may be positioned accurately at a given coordinate. Many of the prior art devices utilize an indexing mechanism which is relatively complicated and which therefore adversely affects reliability of the switch.

SUMMARY OF THE INVENTION The present invention relates to a coordinate slide switch for selectively interconnecting input and output signal conductors.

It is an object of the present invention to provide a coordinate selector switch which is compact in construction and which provides a wiping engagement to effect a switching function which is more reliable than heretofore available. It is another object to provide a slide switch having a structure to provide an indexing action which is simpler than heretofore available. It is yet another object to provide a slide switch assembly which is sealed against the entry of contaminants in the form of dust and the like and yet which is compact. Still another object is to provide an improved matrix switch providing an indication of switch position in a compact package.

The foregoing objectives are achieved by the present invention through an assembly comprised of printed circuit boards held in spaced array with the printed circuit paths oriented in crossing relationship. One of the printed circuit paths has slots in it to define movement of a contact spring carrying element. The contact spring carried by such element is spring biased to engage the printed circuit paths of both boards and to selectively interconnect a given pair of such paths dependent upon position of the element in its slot. The board opposite to the board having the slots therein has a grid of thin plastic material laid over the printed circuit paths with openings leading to discrete areas on the paths. The openings prevent smearing by the contact spring element of the printed circuit paths on the lower board. The openings also provide an indexing action. Each of the contact carrying elements is connected to a thin flexible tape of material such as Mylar with the loose ends of the tape fitted into a cylinder at the ends of the boards. As a contact spring element is moved within the slot of one board the tapes operate to cover the remaining portions of the slots. In one embodiment the cover tapes have symbols or indicia printed thereon which are displayed through a window aperture in the upper board to provide an indication of contact spring element position and coordinate selection of the switch.

In the drawings:

FIG. I is a perspective of the invention switch in one embodiment;

FIG. 2 is a view of a corner of the structure of FIG. 1, partially sectioned;

FIG. 3 is a longitudinal view of the structure of FIG. I, somewhat enlarged;

FIG. 4 is a perspective of a contact spring element used in the switch of FIG. 1;

FIG. 5 is a side view in partial section of the element of FIG. 4, as installed in a switch;

FIG. 6 is an end-on view in section taken along lines 6-6 of FIG. 3;

FIG. 7 is a plan view of the top of the left-hand end of a switch in an embodiment providing an indication of contact position;

FIG. 8 is a side sectional view of the structure of FIG, 7 taken along lines 8-8;

FIG. 9 is a plan view of the top and left-hand corner of a switch in accordance with a further embodiment of the invention providing an indication of contact position and covering of the slots thereof; and

FIG. 10 is a side sectional view of the structure of FIG. 9.

Referring now to FIG. I, assembly I0 represents a coordinate selector switch in accordance with the present inven-' tion. The showing in FIG. I is of a switch which is of an abbreviated capability and it is to be understood that switches of similar construction could be made standard to accommodate dozens of signal paths. The switch is comprised of a lower plate 12 of insulating material having a series of conductive strips 14 on the upper surface thereof (see FIGS. 2 and 3). The plate may be comprised of a printed circuit board suitably etched to define parallel strips of conductive material. Laid over the upper surface of [2 and 14 is a thin sheet 16 of plastic material having series of generally rectangular apertures 18 therein, as shown in FIGS. 2 and 3. The apertures 18 are ap proximately as wide as conductive strips 14 and are aligned with the strips so as to define lines of discrete contact areas on each strip 14. Strips 14 are extended to the edge of the board 12 to be engaged by an edge connector shown as 20 in FIG. I, containing contact springs connected to a series of signal leads 22.

Referring again to FIG. I, a second board 24 is provided for. the assembly 10. Board 24 includes a series of conductive strips 26, as evidenced in FIGS. 3 and 6, extending along theundersurface of the board 24, similar to 14 on 12. Board 24 additionally has a series of slots 28 therein accommodating.

slide elements which extend above the surface of 24 for ease of manipulation. Board 24 is held rigidly spaced from board 12 by spacers shown as 30 at the corners of the two boards and the two boards are suitably fastened together by screws, rivets or the like, indicated as 32 in FIG. 1. Conductive strips 26 on the interior lower surface of 24 are extended out from the right-hand edge, as shown in FIG. 1 to be interconnected by an edge connector 34 which in turn would be suitably connected to signal leads. The signal leads served by 34 and thesignal leads 22 served by connector 20 may be variously considered as input and/or output leads, depending upon the application of the switch 10. Within each slot 28 is a slide element 40 which has a configuration as indicated in FIGS. 3-6. The body of the element is formed of a suitable insulating plastic material with an upper surface thereof stepped as indicated by 42 to accommodate the finger of an operator. The lower portion' of the element includes rounded bearing surfaces 44 and 46 spaced apart and adapted to rest upon the upper surface of the insulating sheet 16. Carried between the bearing surfaces 44 and 46 is a contact spring 48 whichhas a lower contact portion 50 and an upper contact portion 52. Contact spring 48 is mounted within a web extended between 44 and 46. As can be seen in FIG. 3, with respect to the right hand element 40, the lower surface of the slide element includes a plastic detent 54 which is dimensioned to fit within the apertures 18 of sheet 16. As can be seen in FIG. 3, also with respect to the right-hand element 40, spring 48 is dimensioned to position contact 50 toward the center of an aperture 18 and in the center of a contact strip I4. The upper contact 1 surface 52 is positioned to ride on the upper strip 26 of board 24. Spring 48 is also dimensioned to be substantially loaded by its confinement between the interior surfaces of the assembly.

Each slide element is confined by a slot 28 in its engagement with the upper portion of the element. The slide can thus be moved from one end of the slot to the other with the projec tion 54 thereon serving to index such movement to position the contact spring 48 in a series of discrete steps relative to the distinct conductive strips 14. As can be seen from FIG. 5, as an element 40 is displaced the contact surface 52 wipes continuously along a given conductive strip 26 and the opposite contact surface 50 is forced upwardly by the insulating web of a portion of the sheet 16 between adjacent apertures 18. This web is particularized as 17 in FIG. 5. As contact surface 50 is forced up and out of contact with a given strip 14 it is both wiped by the edges of web 17 and prevented from dragging or smearing conductive material from a previously contacted strip 14 to an adjacent strip 14. In addition, as contact surface 50 leaves the web 17, it drops down under a spring force to the next strip 14 to provide a snap action which enhances the con nection made thereby. As can be observed from FIG. 6, with respect to a given position of an element 40, the plastic detent 54 and a contact surface 50 share the same aperture 18, thus tying the indexing action locally to the particular coordinate connection made by the switch. This considerably simplifies the construction of the assembly and the tolerance requirements for the assembly. It does, however, make it important to render the apertures 18 in the plastic sheet 16 rather carefully. This may be readily done by dies used to punch such apertures from the sheet.

Turning now to FIGS. 7 and 8, an alternative embodiment of the invention is shown as a switch assembly 60, the lefthand portion thereof being illustrated. From the top plan view of FIG. 7 an upper board 62 may be observed to contain slots 64 in the surface thereof similar in function and construction to the slots 28 in the board 24. A series of conductive strips 61 extend parallel to slots 64 beneath the surface of board 62. A thin insulating sheet 65 defining apertures 66 can be seen in FIGS. 7 and 8. Conductive strips 68, similar to conductive strips 14 heretofore described, can also be viewed in FIGS. 7 and 8. FIG. 8 shows a lower board 70 and a switch slide element 72 similar to element 40 heretofore discussed. As an additional feature to the assembly of the invention, the upper board 62, as viewed in FIGS. 7 and 8, contains a series of apertures 63 offset from slots 64. Between the

boards

62 and 70 at one end only is a spring loaded roller mechanism 74 provided for each slot 64 and each contact strip 6]. Each roller is comprised of an outer cylindrical element 76 mounted within a bearing block 78 having an interior diameter sufficient to accommodate the roller and a tape element shown as 80. Each mechanism 74 includes a shaft 82 fixed relative to the block 78 and carrying a spring 84 attached to the roller, as shown in FIG. 8. The spring is oriented to be wound up and loaded by clockwise rotation. It is contemplated that an assembly 60 may utilize a common shaft 82 with individual blocks 78 and rollers 76 for each of the tapes 80 in the assembly. Altematively, mechanisms 74 may be independent of each other and fitted between the

boards

60 and 70 in a suitable manner. Each tape 80 is secured to a slide element 72 in the manner shown in FIG. 8 so as to be pulled thereby as the slide 72 is displaced within a slot 64 to provide a selective interconnection of a given pair of

strips

61 and 68. The tape 80 is of a width as indicated in FIG. 7, to remain clear of adjacent slots 64. Printed on the upper surface of the tape are a series of symbols which serve as indicia of the position of the slide element 72 associated therewith. In the embodiment shown in FIGS. 7 and 8, the tape may be comprised of cloth or plastic or other flexible substance. The tension provided by mechanism 74 should be just sufficient to hold the tape relatively flat as a slide 72 is moved to and fro in a slot and not so great as to displace 72 from a set position.

Turning now to FIGS. 9 and I0, a further embodiment of the invention is shown as a switch assembly 90 which is generally similar to the assemblies heretofore described. The assembly 90 includes an upper board 92 having on the undersurface thereof a series of conductive strips 94 and having in such upper surfaces a series of slots 96 which can be viewed in FIG. 9. A selector slide element 98 is provided for each slot and it has a construction generally like that of the

elements

40 and 72 heretofore described. Assembly includes a lower board I00 having a series of conductive strips 102 thereon and having a thin sheet of plastic material 104 attached to the upper surface. The sheet I04 includes a series of apertures 106 aligned over the strips 102. Toward the left-hand end of the assembly as shown in FIG. 9 are provided a series of apertures 93 which permit the viewing of symbols indicative of slide element position. As can be discerned from FIG. 10, at each end of the assembly there is provided a means to accommodate a length ofa flexible tape. The tape is shown as 110 in FIGS. 9 and 10. This means is comprised of a block 112 having a circular internal bore 114 closed at one end by a wall 116 and at the other end by an adjacent block 112, as shown in FIG. 9. Each block includes a thin slit shown as I18 in FIG. 10, just wide enough to accommodate tape 110. The tape employed in the embodiment shown in FIGS. 9 and I0 is flexible and yet is sufficiently stiff to be substantially self-supporting when held at its ends. As can be discerned, one end of each tape is free to coil within 114 of each block 112 and is attachcd to a slide element 98 at the other end, as indicated in FIG. 10. A Mylar tape approximately 0.015 of an inch in thickness has been found satisfactory for the foregoing use. As can be discerned from FIG. 9, the tape is made sufficiently wide to pennit symbols to be placed on one edge thereof so as to be displayed in the windows 93 and at the same time to extend over and cover an adjacent slot 96. With assemblies 90 which are of considerable width, it may be necessary to support the tapes I10 intermediate the ends fitted within blocks 112 and attached to the elements 98. This may be done in a number of ways, including providing an additional slotted board like 92 with a conductive strip provided on the interior surface thereof and with each tape 110 made to ride between such board and a top board. The embodiment of FIGS. 9 and 10 serves to cover the slots 96 to prevent foreign objects from being inadvertently dropped therein. The tapes also provide some protection against contaminants such as dust and the like and thus extend the utility of the switch assembly to environments which may contain such contaminants.

It is contemplated that in the embodiments of the invention containing a symbolic display of slide element position lamps may be placed in behind the tapes with the tapes being made of an appropriate transparent material to present the symbols displayed thereon in contrast.

Having now disclosed the concept for an improved selector switch in various preferred embodiments, the following claims are appended to define what is believed to be inventive.

What I claim is:

l. A switch assembly comprising first and second insulating boards each having a plurality of separate conductive paths on a surface thereof, one of said boards having a series of slots disposed between the conductive paths on such board and the other of said boards having a thin sheet of plastic material containing an array of apertures arranged in rows corresponding with the conductive paths on such board and in columns corresponding to the spacing between the said slots on the other of said boards, means securing said boards into an assembly with the slots and the conductive paths of said one board running generally crosswise to the conductive paths of the other board, a plurality of slide elements mounted in said assembly with a portion thereof extended through a slot to facilitate movement of said element, a further portion of said element fitted between said boards and containing a contact spring means having contact surfaces biased toward the con ductive surfaces of two boards whereby movement of a given element in a given slot causes said spring means to wipe continuously along the conductive path of the said one board containing the slots and to wipe intermittedly over the separate conductive paths on the other board with said thin plastic sheet serving to preclude continuous contact with the upper surface of said other board to avoid wiping of the conductive material thereacross to short out said conductive paths of said other board.

2. The assembly of claim I wherein each of said slide elements includes an insulating detent positioned to engage the apertures of said thin sheet to facilitate indexing movement of said element in said assembly and positioning of said contact surface on a given conductive path exposed by said aperture.

3. The assembly of claim 2 wherein said detent means is of a width approximating the width of the apertures in said sheet and is located relative to said contact surface to position said contact surface toward the center of the conductive path of the lower board when said element is moved to effect a given interconnection between the conductive paths on said one board and said other board.

4. The assembly of claim 1 wherein there is included a thin flexible tape member attached at one end of each slide element and there is provided means at one end of said assembly for spring loading said tape member in a sense to reel said tape member as said slide element is moved toward said means, the said tape member including indicia representative of the position of said slide element and there being provided in the upper board of said assembly an aperture for displaying said indicia as said slide element is moved and as said tape member is drawn past said aperture.

5. The assembly of claim 1 wherein there is provided for each slide element a thin, stiffly flexible tape member joined to said slide element to be moved thereby, means at each end of said assembly for receiving and coiling said tape member as said slide element is moved in a given slot, the said tape member having a width and being positioned relative to a slide element associated with a given slot to cover said slot, notwithstanding movement of said slide clement therealong.

6. The assembly of claim 5 wherein the upper board of said assembly includes at least an aperture associated with at least certain of said slots and said tape member includes indicia thereon whereby movement of said slide element effects a display of said indicia through said aperture as an indication of slide element position and associated interconnection.

7. A coordinate switch including first and second insulating boards having first and second planar conductive paths on surfaces thereof and means to hold said boards with said conductive paths spaced apart and oriented in a crossing relationship, one of said boards including slots and slide elements disposed in said slots, the other of said boards having a thin plastic sheet apertured to define a gridlike surface with the apertures aligned with the conductive paths on said other board, each said slide element including a plastic detent cooperating with the sheet apertures to index the slide element in movement along a slot, each slide element further including a contact spring biased toward said conductive surfaces to interconnect selected paths at a given coordinate, the said gridlike surface serving to prevent smearing between conductive paths intersected by element movement.

8. A slide switch having insulating boards with conductive paths thereon, one board having slots therein with a slide switch element fitted in each said slot carrying means to interconnect the conductive paths of the said boards, a tape means attached to said slide switch element and extending from each end thereof to cover the slot in which the element is fitted, means at each end of said stitch to receive and roll the said tape means as a given slide switch element is displaced along a given slot whereby to cover the said slots of the said switch notwithstanding slide switch element movement.

9. A switch assembly including at least one insulating structure have a plurality of conductive paths on at least a surface thereof, a spring contact mounted on said assembly and biased to engage said path, means to move said contact to wipe over said surface, a plastic insulating sheet positioned between said spring contact and said surface, said sheet including apertures therein serving to provide a detent action for spring contact movement to effect contact with selective paths and to preclude smearing of conductive material between said conductive paths as wiped by the spring contact.

Claims

1. A switch assembly comprising first and second insulating boards each having a plurality of separate conductive paths on a surface thereof, one of said boards having a series of slots disposed between the conductive paths on such board and the other of said boards having a thin sheet of plastic material containing an array of apertures arranged in rows corresponding with the conductive paths on such board and in columns corresponding to the spacing between the said slots on the other of said boards, means securing said boards into an assembly with the slots and the conductive paths of said one board running generally crosswise to the conductive paths of the other board, a plurality of slide elements mounted in said assembly with a portion thereof extended through a slot to facilitate movement of said element, a further portion of said element fitted between said boards and containing a contact spring means having contact surfaces biased toward the conductive surfaces of two boards whereby movement of a given element in a given slot causes said spring means to wipe continuously along the conductive path of the said one board containing the slots and to wipe intermittedly over the separate conductive paths on the other board with said thin plastic sheet serving to preclude continuous contact with the upper surface of said other board to avoid wiping of the conductive material thereacross to short out said conductive paths of said other board.

2. The assembly of claim 1 wherein each of said slide elements includes an insulating detent positioned to engage the apertures of said thin sheet to facilitate indexing movement of said element in said assembly and positioning of said contact surface on a given conductive path exposed by said aperture.

5. The assembly of claim 1 wherein there is provided for each slide element a thin, stiffly flexible tape member joined to said slide element to be moved thereby, means at each end of said assembly for receiving and coiling said tape member as said slide element is moved in a given slot, the said tape member having a width and being positioned relative to a slide element associated with a given slot to cover said slot, notwithstanding movement of said slide element therealong.