US2896053A - Electrical switch blade assembly - Google Patents

Description

July 21, 1959 H. a. FOOTE ETAL ELECTRICALLY swrrcn BLADE ASSEMBLY 2 Sheets-Sheet 1 Filed Aug. 15, 1958 INVENTORS Harold B. Foore Ralph M. Manning by WMX n 33 Their AHorney July 21, 1959 H. B. FOO'TE ETAL 2,896,053

I ELECTRICALLY SWITCH BLADE ASSEMBLY Fil ed Aug. 15, 1958 v 2 Sheets-Sheet 2 INVENTORS Harold B. Foo+e Ralph M. Mannlng by, Their AHorney United States Patet ELECTRICAL SWITCH BLADE ASSEMBLY Harold B. Foote, Lynn, and Ralph M. Manning, Winchester, Mass, assignor's to General'Electi-ic Company, a corporation of New York Application August 15,1958, Serial No. 755,201

10 Claims. .(Cl. 200-166) This invention relatesto electrical switch blade assemblies f the kind employed in automatic time :switches or othermulti-pole switching arrangements in which a plurality of contact spring blades areactuated simultaneously "to perform 'the desired switching functions and, more particularly, to'the linkage arrangementinterconnecting 'the' blades to enable positive switching operations of =.contacts remote from the switch actuating element.

In :designing a spring blade switching assembly, it is desirable to keep the variety of parts constituting the assembly small and to "avoid close fits and tolerances in the design of the parts themselves which would render the parts difficultofmassproduction. It is also desirable to enable ready assembly and disassembly of the switch 'memb'ersfor repair and replacement. However, it is also necessary to insure positive actuation of the switch con- :tacts.

'"lnltheuse of. electrical switches for controlling. elec- .trieal circuits in which relatively high-current flows, it is .rtotiunusualfor the switches to have an inrush current traversing their contacts at the moment of closure as high as '8 or times the normal load current in the circuit, sometimes causing the switch contacts to become :welded together. When it is necessary to open the switch, particularlyin-those instances where the switch is a part of an automatic time switch normally unattended and relying upon a timing motor -to provide the necessary .powerfor opening theswitch, it is extremely important :that the contacts open when required.

It is an object of this invention to provide an'improved multi-pole switch assembly requiring only a minimum number of parts 'which'need not conform to close fits and tolerances, which may be readily assembled and disassembled, and which will permit simultaneous operation oftwo setsof contacts while maintaining suitable gaps and clearances therebetween.

lt is another object of this invention'to provide an improved-switch assembly utilizing a blade linkage arrange- .ment which is simplified in construction and which insures positive actuation of the switch contacts associated therewith.

It is a further object of this invention to provide new and improved means for separatingcontacts of a multipole electrical switch that may have become welded together during closure of the switch.

.Further objects and advantages of this invention will become apparent as the following description proceeds, and the features of novelty which characterize this invention will .be pointed out with particularity in the claims annexed to and forming a part of this specification.

-In 'accordance with oneform of the invention, two pairs ofspacedparalld spring blade members carrying contacts are secured to a terminal board at one end and are interconnected at the other end by a pair of blade links, such that a motor driven time switch operator closing one pair ofcontacts throughdirect actuation on one of the blades of onepair toward the other :blade will, through one of "ice the blade links, simultaneouslyactuate one of the blades of the other pair to cause the closing of both pairs. The switch operator at the time of opening directly actuates the other blade of the one pair and through the other blade link tactuates the other blade of the other pair away from the mating blades .thus opening both pairs while assisting the normal resiliency of the blades in breaking any contact welds present. This action 'is facilitated through the second blade link which is movably interlocked with and supported by the first blade link.

All of the energy required for breaking the weld is furnished by the timing motor and is furnished only when so required. In this way, the switch can function for a prolonged period of operation without overloading the motor or the switch itself if no welds occur during such a period'of operation. Therefore, none of the parts of the switch or themotor'itself need be as strong, rugged, or costly as those switches utilizing energy stored in the contact carrying .members for weld breaking.

For a better understanding of this invention, reference may be had to the accompanying drawings in which:

Figure 1 is a perspective view of a time switch mechanism including a switch assembly embodying the invention;

Figure '2 illustrates the'contour of the blade links;

Figure 3 illustrates the pair of blade links during the assembly thereof; and

Figures 4 and 5 are a series of views of the switching mechanism in various positions .assumed in operation and useful in explaining the operation thereof. Portions of 'the'top views thereof have been omitted for clarity.

Referring to Figure 1, the switch comprises "an operator 1 having thereon :aplurality of operator cams 2 extending longitudinally thereon and adapted to engage and actuate thevswitch assembly shown generally as 3. The switch operator 1 is rotatablyactuated by the sequential engagement of actuator elements 4 adjustably secured to the timing dial 5 with the actuator cams 5. The timing dial 5 is rotated at a constant speed by connection through gears 6 and 7 to asynchronous drive motor 8. The positioning of the adjustable actuator elements 4=on the-timing dial 5 will determine the scheduling of the-sequentialoperationof-the switch assembly '3. The arrangement thus far described is shown andmore fully described in the copending application of William I. Schultz andOarl F. Van Bennekom, filed November 18, 1957, .having Serial No. 697,206, and assigned to the same assignee as the present application.

The switch assembly 3 is mounted on an integral terminal board 10 and has secured thereto a plurality'of switch .bladesll, 12, .13, and 14 which are secured at one end in a manner more fully described in the copending application of Warren N. Kernander and Carl F. Van Bennekom,.filed.July :19, 1956,.having SerialNo. 598,951, and assigned to the same assignee as the present application.

The pairs of parallel deflcctable resilient blade members 11, 12.and 13, 1-4. carry contact pairs 15, 16 and 17, 18, respectively. Blades .11 and 12 along with their associated contacts .15 and 16 operate in combination as an electrical switch, while blades 13 and 14 along with their associated contacts 17 and 18 operate in combination as a second electrical switch. Each switch pair maybe connected .to an external circuit by leads (not shown) attached to terminal screws 9 (see Figure 4). A pair of identical blade insulating links 20 and 21 interconnect the pa'irs 'of switch blades 11, 12 and 13, 14.

The blade links 20 and '21 are "stamped from a sheet of A3" insulating material, such :as that sold under the trademark 'Textolite, in the form shown in Figure 2. Referring to Figure '2, the blade link 20 comprises a central member "22 having an L-shaped slot -therein including a central portion 23 and a leg portion 24. One end of the blade link has a tab portion 25 extending .from the central region thereof, while the opposite end extending from the bottom edge 27 of the L-shaped slot to the end 28 into which the end slot 26 is cut.

The blade link 21 is identical with link 20 and the parts thereof are identified in the drawings with the same numerals and an associated prime The assembly of the blade links 20 and 21 may be conveniently accomplished as follows:

Referring to Figure 3, blade link 20 is positioned perpendicular to blade link 21 and brought together such that the leg portion of the L-shaped slot of link 20 is mated with the end slot 26' of link 21. This mating is facilitated by the fact that the slots 26 and 26' are wider than the thickness of the blade links 20 and 21. Blade link 20 is then rotated in a clockwise direction around interior portion 29' of link 21 until the end slot 26 of link 20 is parallel with blade 21 and free to slide within the central portion of the L-shaped slot 23' of blade link 21, while the end slot 26' of blade link 21 similarly cooperates with the central portion of the L-shaped slot 23 of blade link 20. As best shown by Figures 4 and 5, the blade links are movably interlocked, with the tab portions 25 and 25' extending in opposite directions and the blade links 20 and 21 extending in planes mutually perpendicular to one another.

The blade links 20 and 21 are then mounted intermediate the switch blade pairs 11, 12 and 13, 14, as best illustrated in Figure 1, by inserting tab 25 of blade link 21 through tab opening 31 in switch blade 12. Similarly, tab portion 25 of blade link 20 is inserted through tab opening 32 in switch blade 13. The tab opening 31 may conveniently be in the form of a horizontal rectangular opening to accommodate the horizontal tab portion 25' of blade link 21, while the tab opening 32 of switch blade 13 may conveniently be in the form of a vertical rectangular opening to accommodate the vertically extending tab portion 25 of blade link 20. The tab openings 31 and 32 are sufliciently large so that tab portions 25 and 25' pass loosely through and may move freely relative thereto. To insert the tab portions, the resilient switch blade pairs 11, 12 and 13, 14 may be manually separated and then allowed to resiliently close over tab portions 25 and 25'. The resiliency of the blades 11, 12, 13, and 14 is such that they tend to move toward operator 1 but are restrained by the blade links 20 and 21 and the operator 1.

The switch assemblies are now interconnected by the movably interlocked blade links 20 and 21 and will operate as follows:

Referring to Figure 4, the switch operator 1 has been rotated such that operator cam 2 has contacted switch blade 14 and moved the contact 18 associated therewith to a suitable position to complete the electrical circuit through contact 17 when blade 13 drops ofi of cam 2. At the same time, the movement of switch blade 14 is directly coupled through blade link 20 and the contact made by tab portion 25 of blade link 20 with blade 14, as illustrated in both Figures 1 and 4. Blade link 20 is movably interlocked with blade link 21 and is supported by the slides over blade link 21. Switch blade 12 is simultaneously actuated toward switch blade 11 through the contact with end 28 of blade link 20, and the resiliency of blade 11 causes it to follow blade 13 toward the operator 1 and facilitate the closure of the 4 contacts associated with blades 11 and 12. Link 20 will act as a spacer between blades 11 and 13.

The pairs of switch blades 11, 12 and 13, 14 will remain in the closed position during the period when operator cam 2 is in engagement with switch blade 14. Upon further rotation of switch operator 1 in the direction of the arrow as shown in Figures 4 and 5, the curved edge of operator cam 2 passes out of engagement with switch blade 14. Since switch blades 12 and 14 were deflected away from switch operator 1 during the on" or closing actuation, the normal resiliency of blades 12 and 14 tends to drive them toward operator 1. The force of blade 12 is coupled to blade 14 by blade link 20. Switch blade 13 is prevented from following blade 14 by cam 2, and blade 11 is prevented from following blade 12 by the spacing action of blade link 21. The net result is a snap action which by itself tends to open the contacts associated with blade pairs 11, 12 and 13,

However, as is often the case in automatic time switching devices, the contacts may have become welded such that the snap action and the normal resiliency of switch blades 12 and 14 may be insutncient to overcome the contact welds which may have formed at closure. The weld is broken as best shown in Figure 5, wherein cam operator 2 after passing out of engagement with switch blade 14 over the top of free end 19 of switch blade 14 engages switch blade 13 to not only prevent it from following blade 14 but to drive it in a direction away from switch blade 14. Switch blade 14 is shorter than switch blade 13 to facilitate the sequential engagement of the blades with operator cam 2.

The actuation of blade 13 by cam 2 is simultaneously coupled to switch blade 11 through blade link 21 to open both pairs of contacts as follows: blade link 13 engages blade link 21 at end 28 thereof, with blade link 21 being movably interlocked and supportedby blade link 20 such that tab portion 25 is slidably supported by and passes through tab opening 31 in blade 12 to engage switch blade 11 and cause it to move away from switch blade 12. The combination of the normal resiliency of blades 12 and 14, tending to openthe switch pairs, coupled with the action of cam operator 2, driving blades 11 and 13 away from blades 12 and 14 in a direction opposite to the resiliency of blades 12 and 14, is sufiicient to overcome and break contact welds which might be present and insure a positive action of the switch pairs.

It is thus apparentthat an uncomplex switch blade linkage has been provided which is readily assembled and disassembled and which will insure positive action of a pair of switch contacts to both the closed and open positions even in the presence of contact welds.

Therefore, while a particular embodiment of the subject invention has been shown and described herein, it

is in the nature of description rather than limitation, and it will occur to those skilled in the art that various changes, modifications, and combinations may be made within the provisions of the appended claims and without departing either in spirit or scope from the invention in its broader aspects.

What we claim as new and desire to secure by Letters Patent of the United States is:

l. A switch assembly comprising at least two pairs of resilient spaced apart blade members, said blades being secured at corresponding ends, and a pair of movably in terlocked, mutually supporting blade links interconnected such that actuation of one of the blades of one pair will produce actuation of one of the other blades of another pair through actuation of one of said blade links therebetween and actuation of the other blade of said one pair of blades will produce actuation of the other blade of said other pair of blades through actuation of the other of said blade links therebetween.

2. A switch assembly comprising a first and a second pairv of resilient spaced apart blade members, said blade assume members being secured at corresponding ends and carrying contacts at the other ends positioned such as to contact each other when the blades of each pair are moved toward each other, and a pair of movably interlocked, mutually supporting blade links interconnected such that actuation of one of the blades of said first pair of blades will produce actuation of one of the blades of said second pair of blades through one of said blade links therebetween and actuation of the other blade of said first pair will produce actuationof the other blade of said second pair through the other of said blade links coupled therebetween.

3. A switch assembly comprisinga first and a second pair of resilient spaced apart blade members, said'blade members being secured at corresponding ends and carrying contacts at the other ends such asto provide electrical contact between blade pairs when the blades of each pair are relatively moved toward each other, and a pair of movably interlocked, mutually supporting blade links interconnected such that the movement of one of the blades of the first pair of blade members toward the other blade of said first pair causes a similar movement of one of the blades of said second pair of blade members relative to the other blade of said second pair through the movement of one of said blade links coupled therebetween and movement of the other blade of said first pair away from said one blade of said first pair causes a similar movement of the other of said blades of said second pair relative to the other blade of said second pair through the movement of the other of said blade links coupled therebetween while the bias developed by the deflection of said first and third blades drives such blades away from the second and fourth blades respectively with said first blade link acting as a spacer between said first and third blades.

4. A switch assembly adapted for timing operations comprising a first, second, third, and fourth spaced apart resilient blade member, said blade members being secured at corresponding ends and carrying contacts at the other ends such that the contacts associated therewith will electrically close when said first and second blade members are moved toward each other and the contacts associated therewith will electrically close when said third and fourth blade members are moved toward each other, and a pair of movably interlocked, mutually supporting insulating blade links interconnected such that actuation of the first blade toward the second blade will cause actuation of the third blade toward the fourth blade through one of said blade links coupled therebetween, and actuation of said second blade away from said first blade will cause actuation of said fourth blade away from said third blade through the other of said blade links coupled therebetween.

5. A switch assembly adapted for timing operations comprising a first, second, third, and fourth spaced apart resilient blade members, said blade members being secured at corresponding ends and carrying contacts at the other ends such that the contacts associated therewith will close when said first and second blade members are moved toward each other and the contacts associated therewith will close when said third and fourth blade members are moved toward each other, and a pair of blade links connecting said blade members such that actuation of the first blade toward the second blade will cause actuation of the third blade toward the fourth blade through one of said blade links coupled therebetween, and actuation of said second blade away from said first blade will cause actuation of said fourth blade away from said third blade through the other of said blade links coupled therebetween.

6. A switch assembly adapted for motor driven timing operations comprising a first, second, third, and fourth spaced apart resilient blade member, said blade members being secured at corresponding ends and carrying contacts at the other ends such that the contacts associated therewith will electrically close when said first and second blade members are moved toward each other and the contacts associated therewith will electrically close when said third and fourth blade members are moved toward each other, and a pair of substantially identical movably interlocked, mutually supporting insulating blade links supported by portions passing loosely through said second and third blades enabling sliding engagement therebetween, said blade links interconnected such that actuation of the first blade toward the second blade will cause actuation of the third blade toward the fourth blade through one of said blade links coupled therebetween, and actuation of said second blade away from said first blade will cause actuation of said fourth blade away from said third blade through the other of said blade links coupled therebetween.

7. A switch assembly adapted for motor driven timing operations comprising a first, second, third and fourth spaced apart resilient blade member, said blade members being secured at corresponding ends and carrying contacts at the other ends such that the contacts associated therewith will close when said first and second blade members are moved toward each other and the contacts associated therewith will close when said third and fourth blade members are moved toward each other, a pair of substantially identical movably interlocked, mutually supporting insulating blade links supported by portions pass ing loosely through said second and third blades at said other ends enabling sliding engagement therebetween, said second blade being shorter than said third blade, and a switch operator adapted to sequentially actuate said first and second blades in the same direction, said blade links interconnected such that actuation of the first blade toward the second blade will cause actuation of the third blade toward the fourth blade through one of said blade links coupled theretween, and actuation of said second blade away from said first blade will cause actuation of said fourth blade away from said third blade through the other of said blade links coupled therebetween.

8. A switch assembly adapted for motor diiven timing operations comprising a first, second, third and fourth spaced apart resilient blade member, said blade members being secured at corresponding ends and carrying contacts at the other ends such that the contacts associated therewith will close when said first and second blade members are moved toward each other and the contacts associated therewith will close when said third and fourth blade members are moved toward each other, and a pair of insulating blade links supported by tab portions passing loosely through said second and third blades enabling sliding engagement therebetween, said blade links comprising substantially identical members each having a tab portion at one end, a slot centrally located in the other end, and a slot in the central region such that the links may be assembled in movably interlocking, mutually supporting relationship with the links perpendicular to one another, and like parts extending in opposite directions with the central region slots and end slots being in mutual sliding engagement, said blade links interconnected such that actuation of the first blade toward the second blade will cause actuation of the third blade toward the fourth blade through one of said blade links coupled therebetween, and actuation of said second blade away from said first blade will cause actuation of said fourth blade away from said third blade through the other of said blade links coupled therebetween.

9. The switch assembly as defined in claim 8 wherein said central region slots are L-shaped to facilitate the assembly and disassembly of the pair of blade links and said tab portions pass through said second and third blades.

10. A switch assembly adapted for motor driven timing operations comprising a first, second, third, and fourth spaced apart resilient blade member, said blade members being secured at corresponding ends and carrying contacts at the other ends such that the contacts associated therewith will close when said first and second blade members are moved toward each other and the contacts associated therewith will close when said third and fourth blade members are moved toward each other, a pair of insulating blade links interconnecting said blades, said blade links comprising substantially identical members each having a tab portion at one end, a slot centrally located in the other end, and a slot in the central region with the slots being wider than the thickness of said links such that the links may be assembled in movably interlocking, mutually supporting relationship with the links perpendicular to one another and like parts extending in opposite directions with the central region slots and end slots being in mutual sliding engagement, said second blade being shorter than said third blade, and a rotary motor driven switch operator having a cam surface adapted to sequentially actuate said first and 'second'blades, said blade links interconnected such that actuation of the first blade toward the second-blade will cause actuation of the third blade toward thelfourth blade through one of said blade links coupled therebetween and actuation of said second blade away from said first blade will cause actuation of said fourth blade away from said third blade through the other of said blade links coupled therebetween while the bias developed by the deflection of said first and third resilient blades drives such blades away from the second and fourth blades respectively with said first blade 7 link acting as a spacer between said first and third blades.

No references cited.

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