US2991344A

US2991344A - Push button a. c. switch

Info

Publication number: US2991344A
Application number: US771002A
Authority: US
Inventors: George B Benander; Walter C Schumacher
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1958-10-31
Filing date: 1958-10-31
Publication date: 1961-07-04
Anticipated expiration: 1978-07-04

Description

July 4, 1961 G. B. BENANDER ET AL 2,991,344

PUSH BUTTON A.c. swTTcH Filed oct. 31, 1958 Ueifed Sarah@ 011i@ 2,991,344 PUSH BUTTON A.C. SWITCH George B. Benander, ()aklawn, and Walter Crlsch'u'- macher, Providence, RJ., assignors to General Electric Company, a New York corporation Filed Oct. 31, 19'58, Ser. No; 771,002 8 Claims. (Cl. 200'156) vThe present invention relates to electric switche'sand particularly to a fast make and slow break A.C. switch with a push button switch actuator.

k'I'he increasing popularity of silent mercury switches has fosteredV in recent years the development of more quiet switch mechanisms for use in `resid'ental wiring. Switches that are used inD.C. circuits require avsrnap acting mechanism to extinguish the electrical arc that is drawn between the contacts. This does not hold true for A.C. circuits because the current reaches a zero value 120 times per second and facilitates the ease of extinguishing the arc when the circuit is opened. Since alternating current is widely used today, switches are now being designed thaty will only operate in alternating current circuits. Such switchesY haveA fast make and slow break contacts which make very little noise as the contacts open and close.

The principal object of this invention is to provide a quiet A.C.k switch with a push button switch actuator that has a novel springing arrangement for the ratchet mechamsm.

A further object of this invention is to provide a quiet sounding push button A.C. switch with a` ratchet mech-anism that has a springV means which performs the dual function of resisting the downward movement of the push button and supplying'the pawl with the necessary resilience on the return ofthe button.

A further object ofV this invention is to provide a push lbutton switch with av resilient bearing support and bumper means for the switch actuator to reduce the noise of the switch mechanism to a minimum.

The present invention is embodied in a compact switch design with a push button switch actuator, screwless wire terminals, and a neon glow lamp and resistor assembly within ka translucent switch actuator to illuminate the actuator and Iserve las a finder light. A ratchet wheel, is rotatably mounted within the housing and has a camming member `associated therewith that engages the movable contact means for opening `and closing the circuits through the switch. The switch actuator is pivoted |at one end to the switch housing while the opposite end is provided with a fulcrum means for a pawlthat cooperates with the ratchet'wheel'. This pawl is a relatively stii member that is pivotally mounted to the switch actuator. Associated with the pawlis a compression spring that is seated in the housing and bears vagainst the pawl' adjacent its pivoted end. This spring `means serves the dual function of resisting the downward movement of the switch actuator andit also allows the pawl to pivot as the p awl wipesthe teeth of the `ratchet wheel when manual pressure is released frorn the actuator.` l

Our invention-will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

FIGURE 1 is an isometric view of Ka push button A.C.` switch embodying the present invention. Y

FIGURE 2 is an exploded view of the switch of FIG- URE 1 showing va portionv ofthe switch housing cut away to exposerthe interior thereof. Y k

FIGURE 3 is a cross-sectional elevational View of the switch of FIGURE 1 showing'the` nature of the caminingV means `for holdingthel movable contact vof the switchin the open position;

FIGURE 44 is a cross-sectional view similar to that of Z FIGURE 3 l.fifa-.r the' switch has been operatedfone am to close the circuit through the movable contact.

FIGURE 5 is across-sectional view through the center; of the switch to provide an improved showing ofjpthwe'A springing means for the pivoted pawl of the switch actuai tor. r

Referring in `detail to the drawing and in particular lto FIGURE 1, there is shownl a switch formed by a recessed base member 11, a'switch lactuator 1'2 `and a metal mount'-u ing strap 13. As seen in FIGURE 3, the switch actuator` 12 extends the length of the open top wall of the recessed; base 11. Hence, it is `not necessary to addl a separate insulating plate underneath the metal strap 13 `as inpriqif art devices. As is commonly done in this Iart, metal strap 13 has bendable tabs 14 which are formed downwardly to engage with suitable abutments 15 on the endwalls of the base 11 for holding the switch in an assembled coni dition.

Turning now to -a consideration of the explodedview of FIGURE 2, the metal mounting strap 13 is shown at the top with the push, button switch actuator 12 just beneath the strap. AAt the lower extremity of the figure the recessed base member 1'1 is seen with portions of the walls' cut away to expose the interior thereof. |Iihe base 11 has two opposed side walls 20, two opposed end walls 2 1 and a bottomv wall 22. Open bearings 23 are formedon; the interior of the side walls 20 for receiving the ends of a shaft of a Vratchet wheel assembly 24. 'Ihis part 24 in-I cludes theratchet'wheeL'a cam member 2S on each side of the wheel and shaft-like ends or trunnions 26 that supportthe wheel from the open bear-ings of the base. ratchet wheel assembly 24 is -a composite member that is molded as a single element from insulating material. n

Thev drawing illustrates in FIGURE 2 a three-way switch that embodies the present invention, but it shouldl be yrecognized that this invention is not limited to an application. Both the single pole and threeway switchesV areV now being produced and they have exhibited uniformly reliable results under test. A three way switch' has ay common pair of fixed contacts 27 and a separate pair of

movable contacts

28, 29. The movable contacts 28' andy 29' alternately engage the common xed contact 27' for controlling the switch circuits. Each contact has a down-turned terminal 30 which is slipped into the base 1`1 between opposedgrooves 31 and thus braced against an end wall 21. These terminals 30 are supoprted on the bottomA wall `22 of the base and -are held down by suitable" strips of fiber insulation 32 land 33. The strips 32 are two in number and they engage in the same grooves 31 as do the terminals 30. All of the strips of

insulation

32 and 33 extend to the top surface of the base and are held' down by the mounting strap 13, as is best seen in FIG- URE 3. p

The strip of insulation 33 is" made in one piece becauseit is associated with a neon glow lamp assembly 34 which includes a resistor 35 in series therewith. The lamp assembly has lead wires 36 which are to be kconnected across the movable contacts 28 and 2 9 so that the' glow lamp will be energized when the switch circuit is open. A pair of small openings 37 are formed in the insulating strip 33 and the lead'wires 36 of the lamp merely extend through the openings a short amount. When the strip 33 is forced into the base between grooves 31 on thef` opposite side walls 20 of the base, the lead wires 36 will be wedged between the end wall 21 and the topmost portion of the terminals 30 of the

movable contacts

28 and 29. This is best seen in FIGURE 4 of the drawing. Each contact terminal 30y has an embossed wire-receiving groove 40. The upper portions olf the terminals do not" include the groove 40 so that it is possible for the '

strips offinsulationA

32 and 33 to' slip"v down behind the contact terminals until they rest on the embossments.

As mentioned previously, the illustrated switch of this invention embodies screwless wire terminals. These terminals comprise locking members 42 which are four in number. Each locking member is provided with a spring locking tongue 43, re-entrant end 44, a movable offset arm 45 and an anchoring portion 46 which is engaged by a lanced tab 47 on the contact terminals 30. Hence, the anchoring portion 46 of the locking members is incapable of moving upwardly since the contact terminals are held fixed within the base by the strips of in'sation 32 and 33. The bottom wall 22 ofthe base includes a wire-receiving opening 4S and an adjacent release opening 49 for each locking member 42 of the switch. Wires are fastened to the switch by merely stripping off a portion of the insulation on the end of the wire and thrusting the wire through the opening 48 to deflect the spring locking tongue 43 until the wire becomes wedged between the locking tongue and the contact terminal 30. This locking principle is well understood in this art and is fully disclosed inthe Benander Patent No. 2,705,785 that is assigned to the same assignee as is the present invention.

Turning back to a consideration of the ratchet wheel 24 with its camming members 25 on either side, the movable contact blades 28 and 2'9 are each provided with a cam follower 50 of folded V-shape formation for cooperation with the lobes of `the cams 25. The

movable contacts

28 and 29 are inherently biased into engagement with the fixed contacts 27. This can be seen in FIGURE 4 of the drawing where the cam 25 is free of engagement with the cam follower 50. The opposite situation is illustrated in FIGURE 3 where the cam has been turned through an angle of 45 degrees so that a lobe or tooth of the cam supports the cam follower 50 in a raised position, thereby holding the circuit open. The two camming members 25 which are on opposite sides of the ratchet wheel 24 are out of phase with each other so that when one cam member holds contact blade 28 open, the other cam member will allow the contact blade 29 to close, and vice versa. This is necessary for the proper operation of a three-way switch, as will be understood by those skilled in this art. As illustrated in FIG- URE 3, one of the

movable contacts

28 or 29 is always pressing down on the ratchet wheel assembly 24 to retain theassembly in its bearings 23. In the single pole switch, an additional through-splice contact (not shown) of generally U shape is used with the single movable and fixed contacts to hold the ratchet assembly down. The two arms of the U-shaped through-splice contact are terminal ends such as terminals 30 and they are confined against the opposite end walls 21. The base of the U-shaped contact merely bridges the two arms or terminals although it is adapted to engage with the related cam member 25 to confine the ratchet assembly in place.

The most important part of the present invention lies in the mechanism for turning the ratchet wheel assembly 24. This mechanism is exemplied by the switch actuator 12, a relatively stiff ratchet pawl 51 and a compression spring 52. First, the switch actuator 12 is a member of insulating material that extends from one end wall 21 to the other, although the actuator is not wide enough to span the space between the side walls of the base. The actuator 12 is of translucent insulating material of ivory color and it is hollow, as seen in FIG- URE 5, to receive the neon glow lamp 34. The actuator has two

end extensions

53 and 54. The main portion of the actuator 12, except for the

end extensions

53 and 54, protrudes through an opening 55 in the metal strap 13. The end extension 53 is a pivot member that has a cross piece 56 which is adapted to seat in an open bearing 57 that extends from one end wall 21 of the base, as best seen in FIGURE 2. T o reduce the noise of the switch action, a miniature spring 58 is fastened in the bearing to resiliently support the pivoted end of the actuator and take up any looseness of fit. An alternative would be to substitute a slug of rubber for the spring 58. To obtain the greatest mechanical advantage, it is preferable to apply manual pressure at a point on the actuator that is remote from the pivoted end 53. Accordingly, the top surface of the actuator is provided with an inclined surface 59 that merges with a perpendicular slope 60, thereby forming an apex 61. Usually, the switch will be mounted in the wall so that the apex 61 will be toward the lower edge of the switch box. Hence, the inclined surface 59 will be facing upwardly toward the person operating the switch. Then it is possible to rub an elbow down over the inclined surface 59 of the actuator to operate the circuit.

The opposite end 54 of the actuator has a similar cross member 62 `and it is adapted to support the pawl 51. The pawl is a relatively stijf member of steel or the like material; It may be considered as having three sections, namely, ablade section 63, a flat heel portion 64 and a clip-on end 65. The clip end 65 is adapted to slip over the cross piece 62 of the actuator, as is best seen in FIGURE 5. The bottom of the actuator bears on the heel portion 64 of the pawl. When downward pressure is exerted on the actuator, the blade 63 of the pawl will engage the ratchet wheel 24 and turn it through an eighth of a turn or 45. A compression spring 52 bears upwardly against the heel portion 64 of the pawl adjacent the clip end 65 to satisfy a dual function. This compression spring 52 not only resists the downward movement of the switch actuator 12 and returns the actuator to the raised position when manual pressure is released. The spring also -allows the steel pawl 51 to pivot about its fulcrum as the blade 63 of the pawl wipes the teeth of the ratchet wheel when the actuator is returning to its raised position. Since the resilient action of the pawl is supplied bythe compression spring 52, the pawl may be made quite rigid, thereby increasing its life span since it is necessary that it act as a compression member in turning the ratchet wheel. As seen in yFIGURE 2, the lower end of the compression spring 52 is provided with a rubber insert `66 which extends within the spring. The spring in turn is seated in a well 67 in the base. The well 67 has a central pin or post 68 over which the spring is dropped. Hence, the rubber insert 66 rests on the post 68 and serves as a stop to cushion the depression of the actuator. The introduction of the novel bearing spring 58 and the bumper l66 represent refinements which lighten the -action of the switch and reduce its noise to a Having described above our invention of a novel push button A.C. switch, it will be readily apparent to those skilled in this art that we have reduced the complexity of the switch mechanism and added several conveniences such as the screwless terminals and the neon glow lamp assembly with a push button switch actuator. We have combined the actuator-return spring with the rigid pawl member so that the pawl of the switch can be expected to have a long life before failure due to fatigue should occur. The switch is remarkably quiet and easy to operate with only a slight manual pressure.

Modifications of this invention will occur to those skilled in this art and it is to be understood, therefore, that this invention is not limited to the particular embodi ments .disclosed but that it is intended to cover `all modications which are within the true spirit and scope of this invention as claimed.

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

1. An electric switch comprising -a housing, a ratchet wheel pivotally supported in the housing, fixed and movable contact means included in the housing, a cam member associated with the ratchet wheel 'for turning therewith and engageable with the movable contact means for opening and closing the circuit through the switch, a pivoted switch actuator being pivoted at one end on a portion of the housing, the mid-section of the actuator constituting a finger piece which extends outwardly of the housing, the opposite end of the actuator having a pivoted pawl that hangs down below the actuator and is engageable with the teeth of the ratchet wheel, and spring means seated in the housing and bearing against the pawl y.adjacent its pivoted end, the spring serving to resist the downward movement of the actuator 4and return the actuator to its norm-al position after it has been depressed, the same spring means also allowing the pawl to pivot as the pawl wipes the ratchet teeth yas the actuator returns to its normal position.

2. An electric switch comprising a hollow housing, a ratchet wheel having a shaft that is supported on the opposite side walls of the housing, camming means included on the shaft for turning with the ratchet wheel, iixed and movable contact means assembled -in the housing, the movable contact means being operated by the camming means for controlling the opening and closing of the circuits through the switch, a push button switch actuator pivotally mounted with a linger piece extending outwardly of the housing, the push button having twoy end extensions, one extension including pivot means about which the push button will fulcrum, the opposite extension serving yas a pivot means for a pawl, the pawl having a free end that is engageable with the teeth of the ratchet wheel so that downward pressure exerted on the push button will yforce .the pawl to rotate the ratchet wheel, a compression spring seated in the housing and bearing upwardly at its opposite end against the pawl adjacent its pivotal support, the spring serving the dual function of resisting the downward movement of the push button and also resisting the pivotal movement of the pawl as the pawl wipes the teeth of the ratchet wheel after manual pressure is released from the push button.

3. An electric switch comprising an insulating housing, a ratchet wheel assembly pivotally suspended in bearings within the housing, a cam member arranged on opposite sides of the ratchet wheel and movable therewith, electrical contact means in the housing which overlie the cam members and confine the ratchet -assembly in its bearings, a switch actuator that is pivotally supported at one end from the housing, the opposite end of the actuator carrying a pawl that cooperates with the ratchet wheel, a compression spring seated in the housing and bearing upwardly against the pawl so that the depression of the actuator will force the pawl to turn the ratchet wheel with its cam members thereby controlling the circuitry of the said contact means.

4. An electric switch as recited in claim 3 wherein the pawl is pivotally mounted to the actuator, and the compression spring bears against the pawl adjacent this pivotal mounting, whereby the spring resists the depression of the actuator and allows the pawl to pivot aside as the pawl wipes the teeth of the ratchet wheel once manual pressure is released from the actuator.

5. An electric switch as recited in claim 4 wherein a rubber-like bumper is confined within the lower extremity of the spring and serves as a resilient stop.

6. An electric switch as recited in claim 4 wherein the switch actuator is pivotally supported in an open bearing that includes a resilient seat for reducing the noise of the switch mechanism.

7. An electric switch with a ratchet mechanism for controlling the position of a movable contact of the switch relative to a xed contact, a pivoted switch actuator that supports a pawl which forms a part of said ratchet mechanism, the actuator being pivotally mounted in a bearing, the bearing having a spring seat for resiliently supporting the actuator.

8. An electric switch as recited in claim 7 wherein the ratchet mechanism includes a compression spring that resists the depression of the switch actuator, the interior of the spring having a rubber-like bumper at its lower extremity which acts as a stop member to reduce the noise made by the switch mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 603,786 Hewlett May 10, 1898 636,458 Scott Nov. 7, 1899 2,209,382 Blattner Iuly 30, 1940 2,684,418 Koch July 20, 1954 2,820,113 Lewis et al. Ian. 14, 1958 2,885,515 Bentley et a1. May 5, 1959 2,933,578 Hubbell et a1. Apr. 19, 1960