US1941721A - Pull socket - Google Patents

Description

Patented Jan. 2, v1934 UNITED STATES PULL SOCKET Mark N. Russell, Syracuse, N. Y., assignor to Pass & Seymour, Inc., Syracuse, N. Y., a corporation of New York Application February 27, 1930 Serial No. 431,910

10 Claims.

This invention relates to switches and more particularly to switches of the pull type such as those commonly used in pull chain sockets.

l It is a general object of the present invention f' to provide a novel and improved switch mechanism of thetype described.

One of the important features of ther invention consists in making the operating member, which operates the switch, from a refractory material so that the heat from large lamps does not have any effect on it.

Another feature of the invention consists in the arrangement of a resilient stop to limit the movement of the operating member under the action Iof thereturn spring so that there is no danger of breaking this relatively frangible member.

Still another important feature of the invention resides inproviding an attaching clip linking the chain to the operating member, and so arranging this clip that it engages the chain guide-to limit the movement of the operating member under the action of the chain, thereby relieving the operating member of all strain at its most advanced position.

Other andvfurther objects and features of the invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawing and following specification, wherein is disclosed a single exemplary embodiment of the invention. It'will be understood, of course, that various changes and rearrangements of parts are contemplated without departing from the spirit of the invention, solong as they fall within the scope of the appendedv claims.

In said drawing: V

Figure 1 is a plan view of the body portion of the lamp receptacle showing the cap removed to expose the switch mechanism in a position of rest;

Figure 2 is a view similar to Figure 1 Ashowing the operating member rotated to its advanced position with thevchain fully extended;

Figure 3 is a vertical central section through the lamp receptacle taken on line 3 3 of Figure 1;

VFigure 4 is a partial vertical section on broken line 4--4 of Figure 1; and

Figure 5 is a perspective view of the chain securing clip.

In the more or less conventional types of pull switches and particularly those associated with lamp receptacles it has beeen the'custom to provide a chain quadrant, disk orarxn of such material as fiber or some phenol condensation prodg uct attached to the ratchet teeth which engage with the metal bridging contact to rotate the same in steps to make and break the circuit. This fiber or similar material served to insulate the chain from the current carrying parts and served its purpose quite satisfactorily because of its cheapness and ease of working until the advent of high wattage lamps. These lamps become so highly heated, particularly wherel they are mounted in a vertical dependent position that they impart a large portion of the heat by conduction and convection to the receptacle or socket. This heat is so great that it results in charring of the liber or phenol condensation product operating member so that it is gradually weakened to such an extent that in a short while it breaks in use.

The present invention contemplates overcoming the above diiiiculty by forming the chain arm, disc or quadrant from a suitable refractory material such for instance, as a vitreous Ymaterial like porcelain. This material is eminentlysatisfactory insofar as strength and ease of working are concerned but it is quite frangible and the present invention provides means to protect this frangible material from the effects of shock and strain in use. A

Referring now to -the drawing, the invention has been illustrated for the sake of convenience in connection with a so-called porcelain socket or lamp receptacle of the type in which the body portion 10 and cover 11 which is ordinarily permanently secured thereto, are separable from vthe cap 12 by which the receptacle is supported. This cap 12 carries the circuit terminals, one of which is shown at 13 so that the cap can be positioned and wired and thereafter the body portion and cover attached thereto by means of the fastening screws 14 and 15 which pass longitudinally through both body and cover and engage in the cap. One of these screws, i. e. 15 forms a conducting member between the terminal 13 and the screw shell 16 of the receptacle.

'Ihis screw shell 16 is received in the customary recess 17 in the cylindrical bodyportion 10 and there is also provided a center contact 18 as is customary. The upper end of the body portion 10 is provided with a recess 19 which registers with a corresponding recess 20 in the cover portion 11 to form a chamber for the reception o the switch mechanism.

The switch proper forms no part of the present invention and is in fact disclosed in the patent to Klein No. 1,277,426, September 3, 1918, but it may be stated to comprise a set of stationary contacts, neither of which is visible for they are recessed in the surface 21, which are adapted to be bridged by the U-shaped bridging member 22 to close the circuit. This member is loosely mounted on a central spindle 23 and carries on its upper surface the ratchet member 24 likewise mounted on the same spindle but having limited relative movement in respect to the bridging member. A spring 25 retains these two parts in a denite relationship until an effort is made to move the ratchet member 24. This is accomplished by means of the operating member 26.

According to the present invention thisop-v erating member is in effect a relatively thick disk of porcelain having a substantially circular conguration with the quadrant portion 27 of greater radius and thickness, on the periphery of which the chain rests as shown in Figure 1, and in addition having at one end of the quadrant the hooked projection 28 to which the chain is at,- tached as will be later described. The lower surface of the chain disc is provided with a sheet of metal 29 secured thereto by arms 30 which pass in slots in the edges and are bent over the top of the disk. This sheet of metal is provided with ratchet teeth to cooperate with those on the ratchet member 24. Preferably two teeth are provided yon the metal plate and four on the ratchet member so that for each quarter turn of the disc in a backward direction it can be engaged with a new set of teeth to move the ratchet member and thus the switch.

The central opening in the chain disc is large as shown at 31 but the central opening in the metal plate 29 has a close t to the bushing 32 on the central spindle 23. This opening' 31 is provided with an oiTset portion 34 to receive the hooked end 35 of the chain disc return spring 36 which surrounds the spindle and has its upper z end attached to an adjusting member 37 which l likewise forms the upper bearing for the central spindle 23. As is customary in constructions of this type the adjusting member 37 fits in a square recess at the bottom of a circular recess of larger diameter so that by pressing in on it against the' thrust of the return spring it may be moved out of the square recess and rotated to adjustl the tension of the spring and then allowed to drop back into the square recess where it is held against rotation. In this manner tension is imparted to the spring to bias the chain disc in a clock-wise direction as viewed in Figures 1 and 2.

It will be understood that to operate the switch the chain is pulled to move the disc in a counterclockwise direction from. the position shown in Figure 1 to the position shown in Figure 2 whereby it moves through an arc of slightly more than 90. In so moving, the teeth on the plate 29 engage those on the ratchet member 24`and move it while tensioning the spring 25 until there is positive engagement between the ratchet member 24 and the bridging member 22 when the switch is moved over the inclined teeth of either the contacts or the intermediate portions on the porcelain Surface 21 of the body and finally a snap 5.

action results which moves the bridging member 90 as clearly described in the patent referred to above. The return spring must be quite strong to bring the disc back into position and to drag the chain after it, when the chain is released, so that considerable velocity is imparted to the disc. If this velocity were suddenly arrested by a rigid stop there would be a likelihood of breaking the frangible porcelain so there is provided a cushion stop. This stop is placed in the way of the projection 28 to which the chain is attached and is conveniently provided by arranging a coiled spring 40 around the screw 15. This spring is somewhat compressed between the walls of the recesses in the cover and the body portion and thus is centered around the screw which is of less diameter than the inner diameter of the spring. Its surface opposite to that engaged by the projection 28 engages the shoulder 39 on the body portion 10 so that the spring is not driven against the screw and its effectiveness lost. It

will be seen from Figure 1 that on its return movement the projection 28 engages this spring which cushions it and prevents breakage.

The chain for operating the switch passes through a funnel-like chain guide 41 which is secured to the body portion as at 42 and has Wide iianges 43 received in slots 44 and 45 respectively in the body and cover. The chain 46 passes through this funnel-like part then over the portion 27 of the disc and is attached to the projection 28.by means of the chain clip 47.

This clip is best seen in Figures 4 and 5 and comprises a sheet of metal having a body portion and bifurcated ends oppositely disposed. One set of furcations 48 are widely spaced and have their ends turned in toward each otheras at 49 whereas the other set 50 are fairly close'tog'ether and are bent back upon themselves as at 51 until their ends are substantially parallel with the body por-V tion. These turned back ends 5l receive between them the end ball of the chain as shown at 52 in Figures 1 and 2. They may be pinched onto this -end ball so that it will be permanently retained in position. The spaced furcations 48 pass over the extension 28 on the chain disc and the inturned ends 49 abut against the narrow web 54 which connects the free end of the projection 28 with the disk 26. It will be seen that in the position of Figure "1, the pull of the clip is substantially tangential to the disc by reason of the chain bearing on the portion 27 thereof. Even when the disc assumes the position shown inFigure 2 this tangential pull is substantially maintained but the chain clip has been drawnaway from the portion 27 and its turned-up ends engage the walls of the chain guide or funnel as at and limit positively7 the movement of the chain. This insures that no movement can be imparted tothe chain to draw it beyond that position shown in Figure 2 so that no strain is put either on the porcelain chain disc or its spindle. Too strong a pull can only result in breaking the chain andrcannot possibly damage the disc. 'Y

The construction just described overcomes one of the major difficulties in receptacles for high powered'lamps and positively insures that the refractory and frangible disc will be as satisfactory in operation and as long in life under its extreme conditions of operation as was the ber disc when used with lamps Voi" low power.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. In a pull chain switch having a stationary and a rotatable contact member, an operating member of frangible material rotatable coaxially with said rotatable contact and having one way engaging means therefor, the combination with said operating member of means limiting the angular movement thereof, one of said limiting means being resilient.

2. In a pull chain switch having a stationary and a rotatable contact member, the combination therewith of an operating member rotatable coaxially with said rotatable contact and having one way engaging means therefor, said operating member being formed of frangible material and a resilient means for limiting the return rotation of said operating member.

3. In a pull chain switch, having a stationary and a rotatable contact member, the combination with an operating member rotatable coaxially with said movable contact and having one-way engaging means therefor, means limiting the movement of said operating member to less than 180, a chain normally arranged on the outer surface of said operating member and passing through a stationary chain guide, a clip attaching the chain end to the operating member, said parts being so positioned that the clip engages the chain guide to limit the movement of the operating member.

4. In a pull chain switch, in combination, stationary and movable contact members, an operating member of frangible material rotatable about a pivot and having means to engage said movable contact to actuate the switch, a chain to move said operating member, a spring to return said operating member after movement by said chain, and a yielding stop to limit the return of said operating member.

5. In a pull chain switch, in combination, stationary and movable contact members, an operating member of frangible material rotatable about a pivot and having means to engage said movable contact to actuate the switch, a chain to move said operating member, a spring to return said operating member, after movement by said chain, and a coil spring forming a limit stop for the return of said operating member.

6 In a pull chain switch, in combination, stationary and movable contact members, an operating member of frangible material rotatable about a pivot and having means to engage said movable contact to actuate ythe switch, a chain to move said operating member, a spring to return said operating member after movement by said chain and a coil spring having its axis parallel to the pivot of said operating member to form a limit stop for the return of said operating member.

7. In a pull chain switch, in combination, a disc of frangible material pvoted for rotation, a chain secured to said disc to rotate it, cooperating means to relieve the disc of the pull on the chain at one end of its movement, and means tov provide a cushion stop for movement of the disc in the opposite direction.

8. In a pull chain socket, in combination, a body portion containing lamp engaging contacts and a cover member of insulating material, a switch mechanism enclosed between said body portion and cover and including an operating member of frangible material, a chain secured to said operating member and passing to the outside of the socket, a cap for said socket and containing circuit terminals, a screw to mechanically and electrically connect a cap terminal to a contact, a spring to return said operating member against the pull of the chain and a coil spring surrounding said screw and forming a stop for said operating member.

9. In a pull chain socket, in combination, a body portion having a lamp contact, a cover member of insulating material, switch mechanism between said body and cover mechanism and including an operating member of frangible material adapted to be partially rotated in one direction, a spring to return said operating member to position, a cap for said socket having a circuit terminal therein, a conductor connecting said contact to said terminal and a cushion member on said conductor forming astop for said operating member when it returns.

10. A device for connecting a chain to a refractory operating member comprising a sheet of metal having a body portion bifurcated at two opposite ends, one set of furcations being widely spaced and having their ends turned toward each other, the other set of furcations being curved out of the plane of the body portion until their ends face in substantially the same direction as the rst mentioned set of furcations.

MARK N. RUSSELL.

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