US2828372A

US2828372A - Electric switch operating means

Info

Publication number: US2828372A
Application number: US422892A
Authority: US
Inventors: Bulgin Arthur Frederick
Original assignee: AF Bulgin and Co PLC
Current assignee: Checkit PLC
Priority date: 1953-04-20
Filing date: 1954-04-13
Publication date: 1958-03-25
Anticipated expiration: 1975-03-25
Also published as: GB738422A

Description

March 25, 1958 A. F. BULGIN ELECTRIC SWITCH OPERATING MEANS Filed April 13, 1954' 2 Sheets-Sheet 1 Inventor, Amma mam/ck fillLG/M March 25, 1958 A. F. BULGIN 2,328,372

su zcmc swnca OPERATING MEANS Filed April 13; 1954 2 Sheets-Sheet 2 5O 0 Inventor Tl/ K FKE'ER/(K M9146 W/ a xi? Attorney:

United States Patent 2,828,372 ELECTRIC SWITCH OPERATING MEANS Arthur Frederick Bulgin, Southend-on-Sea, England, as-

siguor to A. F. Bulgin & Company Limited, Essex, England, a British company Application April 13, 1954, Serial No. 422,892 Claims priority, application Great Britain April 20, 1953 8 Claims. (Cl. 200-17) This invention relates to electric switches such as are operated by means of a plunger or press button and is particularly concerned with such switches as operate with a snap action produced by an over-centre mechanism operated by a plunger or button. It is, however, also concerned with various other forms of switch which may be operated in a similar way. These switches are often operated by means of an external lever which bears against the plunger or button and which is usually in the form of a flexible lever fixed at one end to the switch casing and operated by flexing about its fixed end. The operating characteristics of the switch, particularly the force which has to be applied and the extent of movement necessary to operate it, depend on the length of the lever and the relative positions of its mounting and its point of contact with the plunger. The object of the present invention is to provide an operating mechanism which avoids the flexing of the operating lever and which can be readily adjusted or set for different operating characteristics.

According to the present invention, the operating lever is pivoted and a number of pairs of pivot points for the lever situated at ditfering distances from the plunger or push button are provided in a pair of parallel brackets fixed in relation to the casing of the switch. The lever is arranged to be pivoted to any selected pair of pivot points so that according to the pivots selected so the operating characteristics of the switch may be varied at will. Thus it will be understood that not only can the pivot points be chosen at will, but also the nature of the oper-- ating lever itself can be correspondingly selected to give a wide variety of types and operating characteristics of switch with a very small number of components.

Preferably the pivot points are constituted by opposite pairs of holes in the brackets co-operating with projecting pivots on the lever. In this way the lever is able to turn freely so that no flexing is required. In addition a single design of bracket can be used for a variety of switches with different plunger or button positions.

Switches of this kind are frequently of a flat or substantially rectangular construction and the two brackets can be mounted on opposite sides so that the switch is sandwiched between them and may be held by bolts and nuts. Thus the two brackets may be made identical, leading to simplicity in manufacture and assembly. If a number of switches provided with brackets in this way are to be mounted side by side each with a pair of brackets, it is important that adjacent levers and their pivots shall not interfere with one another. For this purpose, the holes may be formed in a portion of each bracket which is indented so that the distance between opposite holes is slightly less than the width of the switch. Thus when the pivots of the lever are inserted in position they will not project beyond the sides of the switch and there is, no danger of fouling an adjacent switch.

As an alternative, however, to securing the brackets to the side of the switch, they may be secured to the surface 2,828,372 Patented Mar. 25, 1958 ICC -of the casing from which the plunger or push button extends. In this case the brackets may be spaced inwardly from the sides of the switch so that there is no danger of fouling an adjacent switch.

As already mentioned, a wide variety of operating levers may be used with the same pair of brackets. These levers may be very simply constructed, for example, from sheet material, the pivots being formed as narrow lateral extensions of the lever. If the lever is made of metal, it may be stamped from sheet and have strengthening, as by a rib, formed in it at the same time. The portion of the lever formed of sheet material need only extend as far as its point of engagement with the operating plunger or button; the remainder of the lever can be made of wire or other suitable material and may be of any shape dictated by the operating requirements of the switch.

Normally the width of the broadest part of the lever will only be such as to give it sutiicient strength and to provide adequate bearing surface for engagement with the operating plunger or button. If desired, however, the lever or part of it may be broadened out so as to extend across two or more switches so as to operate them together; In this case the brackets are mounted on the outer portions of the outer switches of the assembly. The lever may operate all the switches simultaneously or in sequence, the latter being achieved for example by means of one or more tongues struck out of the plane of the lever.

If, however, it is desired to operate the switches independently, individual operating levers for the switches may be provided and these may be mounted either on a common spindle extending across the assembly, or .alternatively each switch may be provided with a pair of brackets for pivoting its operating lever. In either case, however, the operating levers may be controlled by cams on a common shaft extending across the assembly.

Examples of switches in accordance with the invention will now be described in more detail by way of example with reference to the accompanying drawings, in which:

Figure 1 is an elevation of one construction of switch;

Figure 2 is a plan view of the switch shown in Figure 1;

Figure 3 is a plan view of two switches of the kind shown in Figure I mounted side by side;

Figure 4 is an elevation of a modified form of switch;

Figure 5 is a plan view of the switch shown in Figure 4;

Figure 6 is a perspective view of an assembly of switches;

Figure 7 is an end view of the assembly shown in Figure 6; and

Figure 8 is a plan view of a somewhat modified form of assembly.

The switch shown in Figure l comprises a casing formed in two halves 1 and 2, pierced by

holes

3 and 4 through which securing screws or bolts may be passed. The switch is operated by a plunger or button 5 and the details of the internal operating mechanism have no hearing on the invention. The plunger 5 is operated by a lever 6, which is stamped from sheet metal and is formed with a strengthening rib 7. As seen in Figure 2, the lever is formed with a pair of projecting portions 8 which constitute its pivots. These pivots may be accommodated in any one of a number of pairs of pivot points constituted by holes 9 formed in brackets 10. These brackets are formed in one piece as a sheet metal member of U section, of which the base is seen at 11 in Figure 2, and which is rivetted to the casing of the switch. It will be appreciated that by slightly springing the brackets apart the pivots 8 can be accommodated in any of the pairs of holes to vary the pivot point of the lever. Thus it will be understood that in this way the operating characteristics of the switch, that is to say, the pressure needed to operate it and the amount of travel required for the operation, can be varied at will over a considerable'range.

As shown the free end of the lever is bent upwardly, this being to suit the particular operating requirements and method of use of the switch in question. It will also be understood that if the operating lever is removed from the pivoted brackets, it can readily be replaced by any other form of lever which may, for example, be straight or bent to any required shape, or alternatively may be made of wire, be provided with an operating roller and so forth. By interchanging the operating lever a wide range of different constructions of switch may be produced with a minimum of components.

As shown in Figure 3, two switches are mounted side by side, being held together by screws passing through the

holes

3 and 4 and secured by nuts 16. In this case the brackets which are shown as 17 are not made as a single U-piece but are L-section and rivetted independently by rivets 18 to the casing of the separate switches. The brackets are, however, provided again with a number of holes 9' so as to provide a number of pairs of pivot points for an operating lever 19. As shown, the operative portion of this lever is made wide enough to act on both the plungers 5 so as to operate both switches simultaneously. Again the operating lever is readily interchangeable and may have its pivoting adjusted at will to vary the operating characteristics of the switches. If, instead of operating the switches simultaneously it is required to operate the switches in sequence, a tongue such as shown in dotted lines at 20 may be struck out of the plane of the lever to act on one of the plungers 5.

The form of switch shown in Figures 4 and 5 is of a different general configuration but is again controlled by means of a plunger operated by a lever 26. In this case the lever is shown as being stamped from sheet metal, but again it will be appreciated that any one of a large variety of operating levers could be used. The pivots of the lever are accommodated in one of a number of pairs of holes 27 formed in bracket plates 28. In this case, the bracket plates are secured to the sides of the switch which is eifectively sandwiched between them as seen most clearly in Figure 5. The brackets are held in position bymeans of screws 29 fitted with nuts 30 and it will be understood that by the use of longer screws a number of switches can readily be assembled side by side. In order to avoid possible fouling of the pivots of adjacent operating levers, the holes 27 are formed in portions of the bracket plate 28, which are slightly indented, as shown at 31 in Figure 5, so that the pivots of the levers do not project beyond the sides of the switch. In this construction again the operating lever may readily be sprung out of one pair of holes and replaced in another so as to vary the'operating characteristics of the switch at will. It will, of course, be understood also that, a common operating lever operating two or more switches assembled side by side as shown in Figure 3 could equally well be used with this construction of switch.

As shown in Figure 6, a number of switches of the same general kind as shown in Figures 4 and 5 are mounted side by side, being held together by screws 35 fitted with nuts 36. At each end of the assembly are a pair of bracket plates 37 and 33 provided with a number of holes 39. These holes accommodate a spindle at} which extends along the length of the assembly and carries the operating levers 41 for all the switches. These operating levers in their turn are controlled by earns 42 mounted on a common spindle 43 which extends between the

bracket plate

37 and 38. As shown, this is provided with an operating knob 44 and an indexing arrangementwhich consists of a spring ball which is pressed into holes 45 in the plate 38.

r 2,828,372 e p I In each of the positions thus defined, one of the cams depresses an operating lever 41 to operate one of the switches. The rotation of the common spindle is limited by a pin 46 working in a part-circular slot 47 in the plate 37. As shown the cams 42 are spaced at equal angular intervals around the spindle 43 so that the switches are operated in succession. It will be understood, however, that the cams could be so arranged so that two or more of the switches could be operated simultaneously and that moreover one cam could be arranged to extend over the width of more than one operating lever. As in all the other constructions, the operating characteristics of the switches may be varied by moving the spindle 40 into one of the other pairs of holes 39.

The assembly shown in Figure 8 represents a slight modification of that shown in Figures 6 and 7. The main difference is that instead of a common spindle 40, each operating lever 50 has its own individual pivots. In other words, this assembly represents a number of switches shown in Figures 4 and 5 complete with their bracket plates 28 mounted side by side. It will be appreciated that in an assembly of this kind, very considerable fiexibility is possible. Thus operating levers 51 may be adjusted independently so that the operating characteristics of the switches may vary from switch to switch in the assembly. Also certain of the switches may be reversed in relation to one another. For example, the electrical terminal tags 51 may project in either direction and as shown two project one way and two the other. This may have certain advantages in giving greater space for the electrical connections and may also be arranged to suit the particular requirements of an individual assembly.

The modification shown in Figure 8 is not provided with any indexing arrangement and the spindle which is shown as 52 may, for example, be driven directly from a continuously rotating shaft, which may, for example, form part of the machine. Thus as the machine is in operation so the various switches are operated in sequence at predetermined time intervals. a

I claim:

1. In an electric switch having a casing, operating means comprising an operating plunger extending through said casing, a lever adapted to bear freely against said plunger, said lever having integral pivoting extensions, and resilient means secured to said casing and providing a plurality of pivotal mountings for said extensions, said pivotal mountings all being located on the same side of said plunger to give a plurality of leverageratios for said lever.

2. An electric switch according to claim 1, wherein said means providing a plurality of pivotal mountings comprises a pair of parallel brackets, said brackets being formed with opposite pairs of pivot holes. k

3. An electric switch according to claim 2, wherein said pair of brackets are formed in one piece as a sheet metal member of U-section..

4. In an electric switch having a casing of flat, substantially rectangular construction, the combination of an operating plunger extending through said casing, a pair of rectangular brackets, each of said brackets including an indented portion having a plurality of holes, means mounting said brackets on opposite sides of said casing whereby the holes in said brackets constitute pairs of pivotal mountings at differing distances from said plunger, and an operating lever formed with pivots for seating in one of said pairs of pivotal mountings, said lever thereby being adapted to bear against said plunger to operate said switch.

5. In an assembly comprising a plurality of plungeroperated .switches secured side by side, each of said switches having an operating plunger meansassociated with it, operating means comprising pivoted lever means engageable with the plunger means of the respective switches for operating said switches, and a pair of brackets secured respectively to the two outermost switches of said assembly, said brackets being formed with a plurality of opposite pairs of holes to form a plurality of pivot points for said lever means.

6. An assembly according to claim 5, wherein said lever means comprises a single lever extending across the plungers of all said switches.

7. An assembly according to claim 5, wherein said lever means comprises a plurality of levers for operating said switches and a spindle extending between said pivot points, said spindle providing a mounting for said levers.

8. In an assembly comprising a plurality of plungeroperated switches, each of said switches having an operating plunger means associated with it, operating means comprising a plurality of pivoted operating levers, means providing a plurality of pivotal mountings for each of said levers, each of said levers being engageable with a plunger means to operate a switch, a control spindle extending across said levers and a plurality of cam means mounted on said spindle for rocking said levers.

References Cited in the file of this patent UNITED STATES PATENTS