US2691702A - Push-button electric switch - Google Patents

Description

K. C. ALLlSON PUSH-BUTTON ELECTRIC SWITCH Oct. 12, 1954 2 Sheets-Sheet 1 Filed March 17, 1949 I r m D 5D Oct. 12, 1954 K. c. ALLISON 2,691,702

PUSH-BUTTON ELECTRIC SWITCH Filed March 17 1949 2 Sheets-Sheet 2 ,2 Q3 I I :1)-

INVENTOR.

BY I 62% Patented Oct. 12, 1954 UNITED STATES PATENT OFFICE Grigsby-Allison Company, Inc.,

Arlington Heights, 111., a corporation of Illinois Application March 17, 1949, Serial No. 81,860

12 Claims. 1

This invention relates to electric switches of the type featuring a number of push-button switches and is particularly applicable to switches for handling complicated circuits in automatic station selection and other operations in a wireless receiving set, inter-communication systems, automatic coin-operated devices, various types of test equipment and the like.

It is an object of this invention to provide an improved switch of this type which is simple and inexpensive in construction and design, and durable and efficient in its operation.

The present invention also provides a multiple push button switch comprising a frame, an insulated support mounted thereon for sliding straight line motion relative thereto, a second insulated support arranged in spaced parallel relation to the path of movement of said first support and fixed on said frame, a series of rigid contacts fixed to said second support, said contacts projecting toward said first support and arranged in spaced apart aligned relation lengthwise of the path of movement of said first support, and means slidably engageable with the contacts on said second support including a 2 Fig. 11 is a fragmentary vertical sectional view taken on line I ll I of Fig. 10.

contact member carried by said first support and connected thereto for limited movement relative to said first support.

Further objects of this invention will appear in the following detailed description, taken in conjunction with the accompanying drawings, forming a part of this specification, and in which drawings,

Fig. 1 is a top plan view of a switch embodying the present invention showing the second insu lated support in fixed relation to the switch frame.

Fig. 2 is an end elevation thereof as viewed from the left side of Fig. 1.

Fig. 3 is a rear elevation as viewed from the bottom of Fig. 1.

Fig. 4 is a bottom plan view.

Fig. 5 is similar to Fig. 1 with the second insulated support removed to expose the details of the push button and the first insulated support driven thereby.

Fig. 6, and Figs. 7 and 8, are eachenlarged detail views showing the locking mechanism in various positions of rotation incident to a cycle of releasing a push button preparatory to further locking thereof in inwardly pushed position as applied to the push button switch appearing at the left hand side of Fig. 4.

Fig. 9 is similar to Fig. 5 with the first insulated support removed.

Fig. 10 is a vertical sectional view taken on line 5 lU-l 0 of Fig. 1.

Fig. 12 is an enlarged fragmentary view, part in section and part in elevation, illustrating the assembly of the first insulated support and the contact member mounted thereon.

Fig. 13 is similar to Fig. 12 with the parts turned about an upright axis through an angle of degrees relative to the position shown in Fig. 12.

Fig. 14 and Fig. 15 are top and bottom views of the parts shown in Fig. 12.

A multiple switch assembly representing an embodiment of the present invention, as shown in the drawings, comprises an insulating panel ll! of Bakelite punching stock or the like, which is arranged across the top or open end of a metal casing of rectangular plan having a bottom wall I 1, front and rear end walls [2 and I3, respectively, and opposed side walls ['6 and HS extending upwardly from the bottom wall. Lugs 9 extending upwardly from the top edges of the walls I4 and i5 penetrate the panel It to provide a rigid attachment thereof to the casing. Mounting of the casing is provided by means of openings provided in the front wall l2 and in portions of the latter extending longitudinally beyond the walls M and 15, as well as openings in the bottom wall, said openings being designated by the reference numeral 16.

Slots [1 and I8, respectively, formed in spaced relation lengthwise of the front and rear walls of the casing provide bearings in which a series of push rods it are supported in parallel spaced apart relation lengthwise of said walls [2 and [3 for sliding movement in a coplanar path in downwardly spaced parallel relation to the panel I0. The slots [8 are arranged in pairs for the reception of laterally spaced guide arms 20 at the rearward end of each push rod [9. The slots I! each accommodates a reduced stem or handle portion 2'! for operating the push rod from a convenient position outside the front wall [2. A coil spring 22 encircling one of the guide arms 20 bears against the inner surface of the rear wall l3 about the slot l8 containing the guide arm of each plunger or push rod I9 to normally urge the latter toward the front wall [2. A stop 24b on the second guide arm 20 of each push rod (except the push rod farthest to the left as in Fig. 1) engages the edge of its bearing slot l8 to limit movement of the push rod in the direction of the wall [3 against the pressure of the spring 22. The holes i do between the slots I! are preferably formed to create burred edges on the inner surface of the front wall t2. These edges present barbs engageable with a composite member or strip 23 of metal and felt or other suitable cushioning material with the felt side away from the inner surface of the wall I 2. After the push rod is positioned with its stem portion projecting through the slot l7 and the guide arms subsequently threaded through the slots [8 in the rear wall of the casing, the push rod is pushed rearwardly to provide clearance between the shoulder 24 and the inner face of the front wall l2 whereupon the strip 23 is dropped into place. Thus the strip 23 acts on the shoulder 24 to maintain the guide arms 29 in outwardly projecting position through the slots [8.

The panel [9 provides a base for a series of spaced apart contact members arranged in single or double rows in upwardly aligned relation to the path of movement of the push rods l9. In one form, the contact members each includes a blade portion 25 protruding from the lower surface of the panel l9 and having an integral mounting portion penetrating openings 26 in the panel H) which terminates in a terminal connecting portion 2! at a distance above the upper surface of the panel. The mounting portion is so anchored within the opening 26 as to maintain a fixed position peripherally of the opening while integral wings 28 formed at the base of the terminal Connecting portion 21 and staking of the blade portion 25 as at 29 cooperate with the edges of the opening 26 to rigidly secure the blades against displacement vertically of the opening 25. Thus the faces of the blade portion, as clearly shown in Figs. 10 and 11, are held in coplanar relation to the faces of the blades 25 of the contacts in alignment therewith lengthwise of the path of movement of the push rod therebelow.

Another type of contact member includes similar blade portions 39 which each form the lower end of angularly bent tongues or ears 3| sheared from an elongated metal conductor strip 32 arranged across the upper surface of the panel H], with its longitudinal axis across the paths of the push rods [9. The tongues 3i penetrate and are anchored within openings 33 similar and at spaced intervals corresponding to the arrangement and spacing of the openings 26, whereby the blade portions occupy positions in alignment with and form complements of the rows containing the contact blades 25. As illustrated in Fig. -l, the present switch includes two such conductor strips 32, each strip having its tongues 3| bent inwardly toward the other strip and arranged to provide contact blades 30 in each strip alternately with the blades 30 of the other strip in alignment with selected rows of contact blades 25. Each of the conductor strips 32 thus provides a bus bar for a multiple series of contact blades 39, and includes a terminal connecting portion at one end thereof, as indicated at 34. This interconnection of the contact blades 30 affords added resistance to strains applied thereto in connection with switching operations.

Each of the push rods I9 is adapted to actuate a contact holder or panel 35 of insulating material such as the composition of panel [0. The panel 35 supports contact members, to be more particularly described hereinafter, for movement toward and away from bridging engagement with selected blades 25 and 30 in alignment with the path of such push rod and secured to the panel ID as hereinbefore described. Each holder 35 has a reduced end portion 38 which has sliding support in a slot 39 in the rear wall 13 of the casing. A lug 40 formed in and extending upwardly from the body of each plunger enters a slot 4| provided in the holder 35 whereby the latter is operatively connected with the associated push rod. An offset 40a formed in the upright edge of the lugs 40 engages the undersurface of the holder 35 about the slot M which in cooperation with the slot 39 in the rear wall l3 of the casing containing the reduced end portion 38 of the holder 35 supports the latter at a fixed distance below and parallel to the lower extremities of the contact blades 25 and 39 attached to the panel Hi. In switches wherein only a single row of contact blades 25 and 30 are used in connection with an associated push rod and contact holder 35, unbalanced resistance developed between the stationary and movable contacts tends to strain the holder 35 about an axis lengthwise of the path of its motion under control of the push rod l9. However, the edges of the slot 39 in the rear wall l3 of the casing act on the portion of the holder 35 extending therethrough to prevent such distortion of the holder.

Referring more particularly to the details of the contact members carried by the holder 35, as shown in Figs. l2, l3, and 14, it is to be noted that each such contact member is mounted in an opening 42 in the holder, which opening is of rectangular plan. Opposite edges 43 and 44 of the opening 42, which are parallel to the line of motion of the holder, present surfaces engageable by the outer faces of spaced upright arm or shank portions 45 connected at their lower ends by a bridge portion 46. Tongues 41 forming lateral extensions of the bridge portion 46 are arranged to overlap the edges of the opening 42 on the underside of the holder 35 whereby the arms 45 are held against upward withdrawal from the opening 42. Branching upwardly from each of the arms 45 and spreading in opposite directions there from lengthwise of the line of motion of the holder 35 is a contact shoe 48 to provide a pair of shoes adapted to span the length of the space occupied by two neighboring blade portions of the contact members projecting from the top panel l9. Each shoe member has a straight horizontal bottom edge portion 49 which engages the upper surface of the holder 35, with the opposite ends thereof at a distance apart approximately equal to half the maximum length of the shoe. A straight edge portion 50 extends upwardly from the end of each bottom edge portion to a height approximately equal to one-half the maximum height of the shoe. The area of the shoe lying above said edge 56 is bounded by an edge 5| of circular contour which terminates in a downwardly offset straight top edge portion 52. A notch or slot 53 intersecting the straight top edge portion 52 centrally of its length divides the shoe substantially throughout its height to form a pair of separated branches of equal size. This separation affords independent resiliency in the branches of each shoe. A circular area bounded by the circular edge 5|, on each of such branches, is preferably formed to present inwardly facing spherical convex surfaces 54 against which the blades 25 and 30 have wiping engagement.

The distance between the tabs or tongues 41 and the bottom edge portion 49 of the contact shoe 48 is slightly greater than the thickness of the holder 35 and that the space between the edges 43 and 44 of the opening 42 in the holder is slightly greater than the space required to accommodate the arms 45. Due to such clearances, the arm portions 45 cooperate with the opening 42 so as to furnish limited movement of the contact shoes 48 relative to the holder for self-align- 5. ment purposes with the stationary blades 25 and 30.

As shown in Fig. 11, the clearance between the uppermost edge portions of the contact shoes 48 and the lower surface of the panel lEl is less than the clearance between the lower edge of the stationary blades 25 and 30 and the upper surface of the holder 35. Under this arrangement, the contact shoes 4-8 are engageable with the surface of the panel ll! to positively maintain the lower edges of the stationary blades 25 and 35 out of engagement with the plate or holder 35, thereby avoiding any distortion or bending of the blades which might develop due to force applied by the holder 35 directly to the. free ends of the blades incident to. switching motions.

As shown in Fig. 9, the push rod positioned farthest to the left. is illustrated in inwardly locked position. This particular push rod is shown as controlled with a latching member 55. which operates independently of the latching means controlling the other push rods detailed in Fig. 9. The latching member 55 appearing in Fig. i is pivoted as at 550i to the underside of. the push rod [9. A notch at the leading end of the latching member 55 is engaged by a lug 55 formed. integrally with the bottom wall of the casing and projecting upwardly and forwardly into the path of the member 55 so as to rotate the latter in a clockwise direction as viewed in Fig. 8. The notch at the trailing end of the member 55 is thereby rotated into a position to be obstructed and engaged by a lug or stop. also formed integrally with the bottom wall of the casing. and projecting upwardly therefrom. When so positioned, the wheel operates to lock the push rod l9 against movement away from an inward position. Upon inward movement of the push rod from this position. the member 55 engages the lug 55 causing the member 55 to move clockwise a distance suiiicient to move the notch formerly engaged by the lug 51 clear of the lug 51. The member 55 is thus engaged by the lug 57 during movement of the plunger or push rod [5 to an outward position toward the front wall i2 whereby the notch at the leading end of the member 55 is prepared for re-engagement with the lug 55 when next movement of the push rod I9 to an inward position is brought about. To enable the push rod l5 to move a sufiicient distance inwardly to accommodate the travel required by the member 55 between the lugs 55 and 55, Without straining the holder 35,. lost motion is afforded between the holder 35 and the push rod lit by elongating the slot. 4| as at Ma which receives the lug 40; The edges of the member 55 extending lengthwise of its center line are so formed as to provide 2. lateral offset. This offset engages the lug 5! so as to stop the rotation of the member 55 while its center line is parallel to the line of motion of the push rod on which it is mounted. It will be noted that this offset projects slightly beyond the lug 51 so as to prevent rotation of the member 55 in a direction counter to the direction which it is intended to be rotated preparatory to its next succeeding position of locked engagement with the lug 57. Movement of the push rod carrying the member 55 described above is limited in the direction of the lug 56 by a stop 24a formed on the arm Ell of the push rod, said stop being engageable with the edge of the opening 18 in the rear wall l3.

The push rod appearing second from the right hand end of the series of push rods shown in Fig. 9, as well as Figs. 1, 4 and 5, is in inwardly locked position under control of a sliding latch bar 58,

with which the push rods appearing third, fourth and fifth from said right hand end also cooperates i-nsuch a way that the inward movement of any one of said push rods automatically releases any other of said push rods already locked in inward position. The latch bar 58 is arranged below the push rods I9 for sliding movement on spaced proiectionsiformed in and extending upwardly from the bottom wall of the casing. One end thereof slides in a recessin an upright member 59 formed integrally with the bottom wall of the casing while the opposite end,.consisting of laterally spaced prongs 55 and 51 have sliding support in notches or recesses formed in the end wall l5 appearing at the right hand end of the unit as viewed in Fig. 9. A coil spring 62 encircling the prong 6i and a section 53 of the bottom wall of the casing acts against the latch bar 58 and. the inner surface of the wall i5 to urge the bar in a direction away from the wall. A locking shoulder 54 is formed on one longitudinal edge of each of the push rods numbered two, three, four and five from the right hand end of the unit as viewed in Fig. 9. The edge portion of each push rod iii in trailing relation to the locking. shoulder 55 according to movement of. the rod into inward position, is beveled laterally outwardly from the inner limits of the locking shoulder, as at 55. Upstanding ears 56 on the latch bar 58 are arranged in alignment with the line of motion of the push rods so as to engage the shoulder (it of a selected rod and hold such rod in inwardly moved position, as will be more apparent from the position of the second plunger from the right as viewed in Fig. 9. Accordingly, upon movement of either of the plungers appearing asthird, fourth or fifth from the right in Fig. 9, the car 55 inthe path of said push rod will be cammed to the right by the bevelled edge 55. thereof so as to release the formerly locked push rod for movement out of inward position. Thereupon the shoulder 55 of the rod which operated to release the formerly locked push rod will be engaged by the ear 55 of the latch bar 58 to thereafter hold such inwardly moved push rod in locked condition.

The push rod positioned farthest to the right in Fig. 9 is provided with a bevelled edge portion 5? cooperating with an upstanding ear 68 at the end of the latch bar 55 whereby inward movement of this rod by the latter operates to release any other push rod adapted to be held in locked position by the latch bar but is not itself held in inwardly locked position by such latch bar.

What is claimed is:

1. An electric switch comprising a frame, an insulated support mountedthereon for sliding straight line motion relative thereto, a second insulated support arranged in spaced parallel r lation to the path of movement of said first support and fixed on said frame, a series of rigid contacts fixed to said second support, said contacts projecting toward said first support and arranged in spaced apart aligned relation lengthwise of the path of movement of said first support, and means slidably engage-able with the contacts on said second support including a contact member carried by said first support and connected thereto for limited movement relative to said first support about an axis lengthwise of the path of movement thereof.

2. An electric switch as defined in claim '1 wherein said contact member connected to the first support is simultaneously engageable with two neighboring contacts on said second support 7 in one position of movement of said first support.

3. An electric switch as defined in claim 1 wherein said contact connected to the first support is movable about an upright axis.

4. An electric switch as defined in claim 1 wherein said contact member connected to the first support is simultaneously engageable with a pair of the contacts on said second support in one position of movement of said first support, and said contact member is divided by a slot extending downwardly from its upper edge substantially midway of its dimension lengthwise of the line of motion of the first support.

5. An electric switch as defined in claim 1 wherein said contact member connected to the first support comprises a shank portion consisting of spaced arms projecting through an opening formed in the first support, and integral portions branching upwardly therefrom and extending in opposite directions lengthwise of the line of motion of the first support.

6. An electric switch as defined in claim 1 wherein the first support is provided with an opening therethrough, and said contact member is connected thereto by spaced arms on said contact member projecting through said opening, and said contact member is retained against withdrawal therefrom by means of tongues formed integrally with a connecting portion at the lower ends of said spaced arms and engaging the bottom surface of the support aforesaid.

7. An electric switch as defined in claim 1 wherein the contact member connected to the first support comprises a pair of shoes presenting inwardly facing surfaces with which the contacts on the second support have sliding engagement, and said inwardly facing surfaces are formed with inwardly facing spherical convex areas thereon.

8. An electric switch as defined in claim 1 wherein said contact member carried by said first support presents edge portions engageable with the surface of said second support to maintain said first support at a distance clear of the contacts on said second supports.

9. An electric switch comprising a frame, a series of independent insulated supports mounted on said frame for sliding straight line motion relative to said frame in a common plane, a second insulated support arranged opposite and parallel to the paths of said first supports and fixed on said frame, a conductive strip arranged on the surface of said second insulated support having integral portions penetrating said second insulated support to provide a blade portion which projects downwardly from said second insulated support, a series of contacts projecting toward first supports and together with said blade portion on the conductive strip are arranged in spaced apart aligned relation lengthwise of the path of motion of said first supports, and a contact member on each of said first supports slidably engageable with said blade portion on the conductive strip and the contacts on said second support in alignment therewith lengthwise of the line of motion of said first supports.

10. In an electric switch the combination of a frame and an insulated support mounted on said frame for sliding straight line motion relative to said frame, said support presenting opposed flat surfaces, each parallel with the other, lengthwise of its line of motion, a slot formed -in said support penetrating said opposed surfaces, said slot having opposed parallel edge portions lengthwise of the line of motion of the support, a contact member comprising spaced apart parallel arms projecting through said slot, a connecting portion at one end of said arms having integral tongues extending therefrom in opposite directions lengthwise of the line of motion of the support engageable with the surface of the support about said slot, a contact shoe branching upwardly from each of said arms and spreading in opposite directions lengthwise of the line of motion of the support beyond opposite edge portions of said slot, the distance between said tongues and the contact shoes being slightly greater than the distance between the faces of said support whereby said contact member has limited movement relative to said support.

'11. In an electric switch as defined in claim 10 wherein each contact shoe is divided substantially centrally of its dimension lengthwise of the line of motion of the support.

12. In an electric switch as defined in claim 10 wherein each contact shoe has a straight bottom edge engageable with the surface of the support with the ends thereof at a distance apart approximately equal to half the maximum length of the shoe, each bottom edge thereupon extending upwardly and outwardly to a height approximately equal to one-half the maximum height of the shoe, and the area of the shoe lying above said slanting edge being bounded by an edge of circular contour.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,146,269 Puerner Feb. 3, 1939 2,196,433 Allison Apr. 9, 1940 2,213,845 Mastney Sept. 3, 1940 2,234,405 Hall et al. Mar. 11, 1941 2,441,614 Baumer May 18, 1948 FOREIGN PATENTS Number Country Date 517,202 Great Britain Jan. 23, 1940 517,898 Great Britain Sept. 13, 1945 673,390 Great Britain June 4, 1952

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