US1493593A - Electric-lamp socket - Google Patents

Description

May 13', 1924. v v/)fgss RKB. BENJAMIN ELECTRIC LAMP SOCKET Filed Sept. 27 1919 2 Sheets-Sheet 1 v v /NI/EN TOR.

' TToR/VEY May 13 1924.

R. B. BENJAMIN ELECTRIC LAMP SOCKET Filed SeD'.. 27

ASSSQS 2 Sheets-Sheet 2 w IN1/E /TOR mM/27172 WR A/ TOM/EY Patented May 13, 1924.

PATENT OFFICE.

REUBEN B. BENJAMIN, OF CHICAGO; ILLINOIS, ASSIGNOR TO BENJAMIN ELECTRIC MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

ELECTRIC-LAMP SOCKET.

Application filed September 27, 1919.

T 0 all whom t may concern.' p

Be it known that I, REUBEN'IB. BENJA- MIN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Electric-Lamp Sockets, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

This invention relates to an electric lamp socket, and more particularly7 to an electric lamp socket construction in which the switching member is provided with improved means for introducing a double break in the circuit continuity. The general trend of lamp socket construction, in view of the present day universal use of electrical household appliances of high wattage consumption, is directed to sockets of increased power rating. This increased wattage rating for lamp sockets may be obtained in a variety of ways, one of which consists in increasing the number of breaks introduced into the circuit by the switching mechanism.

It is one of the objects of this invention to produce a lamp socket iitted with an ims proved mechanism for obtaining a plurality of breaks in the circuit continuity in the operation of the switch mechanism.

Another object of this invention consists in the production of an improved switch mechanism in which arcing at the switch contacts, due to the opening of the circuit, is maintained at a minimum.

Another object consists in the production of an improved switch mechanism of this character which is simple in construction, reliable in operation, and which is very compact, whereby it can bereadily and efliciently assembled in lamp socket construction.

Other features, advantages, and objects of this invention will become apparent from the accompanying illustrations, the following description, and the appended claims.

For the purpose of describing and illustrating the invention, a specific embodiment thereof is illustrated in the accompanying drawings in which Fig. 1 is a plan view of the lamp socket construction with the cap of the socket removed to disclose the switching mechanism;

Fig. 2 is a View of the socket construc- Serial No. 326,831.

tion taken on the plane represented by tne line 2 2 of Fig. 3 looking in the direction of the arrows;

Fig. 3 is a vertical section of the socket construction taken on a plane represented by the line 3 3 of Fig. 1 looking in the direction of the arrows;

Fig. 4 is a vertical section of the upper portion of the socket taken on the plane represented by the line 4 4 of Fig. 1 looking in the direction of the arrows, and illustrates the switching mechanism in the closed position;

Fig. 5 is an illustration similar to Fig. fl, showing the switching mechanism operated to the open position;

Fig. 6 is a vertical section of the upper portion of the socket construction taken on a plane represented by the line 6 6 of the Fig. 1 looking in the direction of the arrows;

Fig. 7 is a Vertical sectional View taken on the plane represented by the line 7 1 of Fig. 1, and illustrates the method utilized for anchoring the pawl operating spring in the insulating base;

Fig. 8 is a perspective view of the commutator, consisting of a combination ratchet and cam wheel;

Fig. 9 is another view of the commutator, and illustrates the reverse face to that shown in Fig. 8;

Fig. 10 is a view in perspective of the pawl plate utilized to rotate the ratchet, and

Fig. 11 is a View similar tor Fig. 5, but showing the switch with the parts 1n tne positions which they occupy just as the first break in the circuit occurs.

As illustrated in the drawings, the socket mechanism is preferably enclosed in a metallic casing consisting of the lower shell 16 and the cap 17. The lower shell 16 is fitted with a downwardly extending cylindrical portion 18 off-set from the upper portion thereof by an annular ledge 19 and fitted within the portion 18 is a circular insulat ing member 2O which separates the portion 18 from the threaded shell contact of the socket 21. The cap 17 is connected to the lower shell 16 in any suitable manner, a large number of which are well known to those skilled in the art, whereby a positive lock is obtained between the shell 16 and the cap 17.

In the specific embodiment of the metallic shell 16 a lateral outlet 22 is provided for attaching the socket mechanism to a fixture. This fixture attaching portion 22 makes the specic embodiment of the invention, herein illustrated, an angle socket, but obviously the invention can be readily incorporated in any or all of the various types of lamp sockets known to the art.

On the down turned upper portion of the insulating sleeve 20, which rests on the annular ledge 19, is an insulating base 24 which serves to receive and mount the electrical switch mechanism, as well as the lamp sockets and circuit terminals.

The switch operating mechanism is located in a chamber 25 in the base 24. The switch mechanism includes a commutator comprisingl` a cam Wheel having two cams; one of which has a greater lift than the other, these cams operating upon a turn of 180 degrees and the face of one cam being of conducting material while the face of the other is of insulating` material. Combined with this cam wheel, and preferably formed integral therewith, is a ratchet disc, the periphery of which extends beyond the surfaces of the cams and forms a barrier between the live parts of the switch and the operating means. The ratchet disc portion of this commutator is formed with ratchet teeth preferably made by indenting or forming notches in the side of the commutator opposite the cam wheel portion thereof. To advance the commutator through 180 degrees of rotation upon each operation of the mechanism, there is provided a ratchet plate which is formed with ratchet pawls or teeth to engage the ratchet notches of the commutator, and is also provided with a chain rail to carry and guide a chain and also with a forked portion adapted to receive the end ball ofthe operating chain. Suitable spring means are provided for returning the ratchet plate and chain after each operation of the switch so that the parts are ready for the next manual operation of pulling upon the chain and advancing the commutator through another 180 degrees of rotation. Combined with this commutator is a novel form of circuit breaking device which opens the circuit at two points in series, upon alternate pulls upon the chain. ln the chamber 25 of the base 24 is positioned a spindle 26 which is rotatably mounted in a slot 2.7 cut in one of the walls of the chamber of the insulating base 24 (see Fig. 7), the other end of the spindle being rigidly secured to the commutator 28, which consists of a coinbination ratchet and cam wheel, as above stated.

The ratchet and cam wheel 2S is composed of some suitable insulating material, and comprises the enlarged disc portion 29, preferably integral with which is the double cam wheel 30. The maximum radius of the cams being less than that of the disc 29, said disc constitutes a peripheral flange extending beyond the periphery of said cams. rl`his flange acts as an insulating barrier between the conducting and operating parts of the switch mechanism which will become apparent from the following description and will be evident from Figs. l and 3. The cam wheel portion of the commutator has two cam faces 3l and 32, each substantially 180 degrees in length. The cam face 8l has a very slight and gradual rise, while the cam face 32 has a larger rise or lift. From the cam faces 3l and 52 there is an abrupt or sudden drop, as shown at 33 and respectively. rEhe drop is much greaterl from the face 3l than from the other face. rlhe spindle 26 is preferably secured to the commutator 28 by embedding the end thereof in the insulating material of which the latter is constructed. rlhe cam face 3l consists of a contact plate 35 which is provided with an arm 36 extending over the side face of the cam wheel to the central portion thereof, where said arm is formed into a hollow metallic sleeve 87, which fits over the projecting cylindrical hub 38 of the commutator 28. Said hub 3S and the enclosing metallic sleeve 37 constitute a journal for the commutator and also serve as the other support for the spindle 2G. The metallic journal 38 is supported in a plate or bearing bracket 40, which is of conducting material. The conducting bracket 4() is secured to the base 24 by means of a screw 4l, the head-end of which is connected by means of a conducting plate 42 to the center contact 43 of the lamp socket.

From the foregoing description, it will now be apparent that the insulating commutator is contained in the chamber and is rotatably mounted by the spindle 2G between the slot 27 cut in the insulating block r9-land the aperture provided in the conducting plate 40, which serves as a lx-aring for the metallic sleeve 37.

The chamber 25 has a narrow extension 47 connected to one side thereof in which is mounted the resilient tl-shaped spring 48, which is normally biased by means of a spiral spring 49 in the direction of the combination ratchet and fam wheel. The U- shaped spring 48 has one of its members 49, due to the aforesaid bias, continually in contact with either one or the other of the faces 3l and 32 of the combined ratchet and cam wheel 28. Consequently, the spring f8-depending upon the position of the cam wheel-is either in contact with the conducting face 35, as shown in Fig. 4, or in contact with the insulating cam face 32, as illustrated in The comn'iutator is operated by means of pawls which may be actuated in any desired manne-r. ln the specic embodiment illustrated, the pawls are carried on a metallic ing pawls 56 and 57, which pawls in the assembly of the switch mechanism are placed adjacent the face 58 of the combination ratchet and cam wheel 28. The disc portion 54; is also fitte-d with the outwardly projecting prongs 59 and 50, which project from the opposite face of the disc from which the pawls 56 and 57 extend. Sub-A stantially normal to the face of the disc 5ft is the flange 54 which lia-nge carries a substantially perpendicular chain rail The chain 53 is attached to the ratchet plate 51 by means of the bifurcated arm 52, see Fig. 6, the chain passing over the iange 5l. he. ratchet plate is preferably made from one piece of material punched and formed into the construction illustrated in Fig. 10.

Either one of the prongs 59 or 60 can be utilized, as illustrated in Fig. 6, to se-v cure one end of a spiral spring 61 to the member 51, the spring 61 being sleeved upon vthe spindle 26 and having the opposite end 62 thereof secured to a ledge 63 provided for this purpose in the insulating base 24, as illustrated in Fig. 7. Con sequently when the chain 53 is operated it will carry with it the ratchet plate 51, which in turn will tension the spiral spring 61. The movement of the' member 51 is conn trolled by a projection 64 thrown into the path` of the said member. The forward movement of said member under the action of thevchain 53 will be limited by the engagement of the forward edge 65 of said member with the protrusion 64, and the return movement-'of the said member will be limited by the engagement of the bifurcated arm 52 with the said protrusion.

The face 58 of the combination ratchet. and cam wheel 28 is provided with the two tapered notches 66 and 67, which notches form ratchet teeth, which cooperate with the pawls 56 and 57 to turn the combination ratchet and cam wheel 28. Thev spring 61A not only returns the pawl carrying plate 51 to position so that the pawls may engage the teeth 66 and 67 but also exerts an expansive force, whereby the disc 51 is held snugly in position against the face 58 of the combination ratchet and cam Wheel 28, and the bearing extension 36 of the contact 35 is held in gooi electrical contact with the bearing bracket 40.

Due to this assembly of parts, it will be evident that when the chain is pulled the disc 51 will rotate and will carry with it the combination ratchet and cam wheel 28 until the forward edge 65 of the member 51 strikes the protrusion 64;. This marks the limit of the forward movement of the mem: ber 51, and upon the release of the chain 53 the combination ratchet and cam wheel 28 will remainin the position to which it has been rotated,l as hereinafter to be described; whereas, the pawl carrying disc 51 will be rotated in the reverse direction under the influence of the spring 61 until thebifurcated ends 52 strike the protrusion 64s. The pawls will then have passed the opposite notches (6G and 67) in the face 58 of the combination ratchet and cam wheel 28, and Will engage therein on the next forward movement of the pawl-carry`A face 35 or the insulated cam surface 32r of the commutator 2S, the rotation of this commutator 28 will obviously cause a movement ofthe U-shaped spring 48. l/Vhen the switch n'iechanisin is in the olf position, as illustrated in Fig. 5, the rotation of the commutator will cause the end of the arm 49 of the tl-shaped spring 4S to move up on the cani surface 32, and thereby move said lll-shaped spring in a direction away from said cam and toward the contacting terminal 70. .ihe movement of this Uishaped spring will take place against the force exerted bythe biasing spring 4-9, and therise in the cam surface 32 is such that the arm 71of the U-shaped spring` will move into contact with the contactmember and the U-shaped spring will be considerably compressed before ther high point on the cam surface 32 is reached. Trnen the high point on the cam sur `ece is reached, the end of the arm i9 of the Ll-- shaped spring 48 will slide over the abrupt stop or shoulder Sli onto the contact plate 35. Thereafter, whenthe pulling force on the chain 53 is discontinued, the member 51 will return to its normal position under the action of the spring 61 as hereinbefore described. The combination cam and ratchet wheel 28, however, vwill remain in its advanced position, being held in this position by the end of the spring' arm i9 which rests against the stop or shoulder 34. l/Vhen this movement has been completed the switching mechanism will be in a position shown in Fig. al.

Upon the next operation of the switching mechanism by the pulling of the chain 53, which results in movements in the pawl carrying disc 51 and the combined ratchet and cam wheel, as hereinbefore described, the arm i9 will ride over the Contact surface 35. When the end of the contact surface is reached, there is an abrupt drop at 33,

whereby contact between the member 49 of the U-shaped spring 48 and the contact surface 35 is first broken or interrupted, and thereafter under the action of the resiliency of the U-shaped spring 48 and the biasing action of the spiral spring 49', the U-shaped member 48 will take the position illustrated in Fig. 5, thereby interrupting or breaking the contact between the member 71 of the U-shaped spring 48 and the contact member 70.

It will now beevident that the cooperative action of the commutator 28 and the U- shaped spring 48, is such, that when the switch mechanism is moved from its open position as illustrated in Fig. 5 to the closed position as illust-rated in Fig. 4, the U- shaped spring 48 will be forced to the right, so that the arm 71 thereof will contact with the contacting member 70. In this movement the cam surface 32 will gradually compress the two arms 49 and 71 of the U-shaped spring 48, and said arms will be under considerable compression when the high point of the cam surface 3Q is reached, whereby good and positive contact will be obtained and maintained between the arm 49 of the U-shaped spring and the contact member 70.

1When the arm 49 of the U-shaped spring reaches the high point of the cam surface 3Q, and passes over the stop or tooth 34, there will be a resulting slight expansion between the arms 71 and 49 of the U-shaped spring, due to the slight drop at 34, but this expansion is so slight that good contact will still be maintained between the arm 71 of the U-shaped spring and the contacting member 70, the arms 71 and 49 of the U- shaped spring still being in compression when in this position, as clearly illustrated in Fig. 4. Due to the expansive force of the U-shaped spring 48, therefore, good positive contact is established between the respective arms of said spring and the contact member 70 and the rotatable contact member 35.

However, when the switch mechanism is operated from the closed position shown in Figure 4, to the open position shown in Fig. the arm 49 of the U-shaped spring will ride over the contact 35 until it reaches the abrupt shoulder or drop 33. As clearly illustrated in the drawing this drop or shoulder 33 is a comparatively long one, the shoulder drop or tooth 33 being preferably made three or four times as deep as the shallow tooth or shoulder 34. Consequently, when the arm 49 reaches the end of the Contact 35, the drop at the shoulder or tooth is such as to permit the U-shaped spring 48 to expand freely due to its own resilience and due to the force exerted by the spiral spring 49, whereby due to the drop, contact between the arm 49 and the contacting surface 33 is broken, as seen'in Fig. 11, and l immediately thereafter the contact between the arm 71 of the U-shaped spring and the contact member 70 is broken, as seen in Fig. 5 and shown in dotted lines in Fig. 11.

As clearly illustrated in the drawing, the combination ratchet and cam wheel member 28 is positioned with its rotation axis transverse to the axis of the socket and to the direction of pull of chain. Consequently' the chain 53 may be so positioned, as illustrated in Fig. 6, that the pulling force exerted thereon is communicated to the combination ratchet and cam wheel 28 in a direct line without the necessity of looping the chains through any curves or angles, which is ordinarily necessary when the axis of rotation of the revolving commutator is parallel to the axis of the socket. Therefore with this construction a direct tangential pull is obtained. Further, since the combination ratchet and cam wheel 28 is provided with but two cam surfaces and two teeth or shoulders, a comparatively small disc can be utilized, and a good, long, smooth positive pull will nevertheless be obtained on the chain for the operation of the switch mechanism. The use of a small disc 28 is practically imperative for the construction of a satisfactory commercial device in order that the desired compactness will be obtained. Because of` the use of two cam faces or surfaces, each substantially 180 degrees in length, a long smooth pull on the chain is obtained, notwithstanding the use of a commutator of small diameter which obviously results in a positive and smooth action of the switch mechanism.

The contact member 70 is integral with the plate 72 which carries the circuit terminal 73. The other circuit terminal is shown at 74, which is connected to a plate 75, the plate 7 5 being secured to the insulating base by a screw 7G which connects the plate 75 and the circuit terminal 74 to the threaded shell contact 21 of the lamp socket.

The circuit of the lamp socket may now be traced as follows:

Assuming that the switch mechanism is in its closed position, the circuit is traceable from the circuit binding terminal 73 through the plate 7 2 to the stationary contact 70 and thence through the U-shaped spring 48 and the rotating contact 35 by way of the conducting strip 36 to the metallic sleeve 37, which is in contact with the conducting bar from where the circuit is traceable by means of the screw 41 to the conducting strip 42 and the center contact 43 of the lamp socket. With a lamp in position the circuit can be traced through the lamp to the threaded shell contact 21 and thence by means of screw 76 to the conducting bar 75 and the other circuit binding terminals 74.

It will be evident that when the commulnacaesoa tator 28 is rotated, as herenbefore described,

4from the closed to the opened circuit position, that the circuit just traced will be opened at two points. First, or primarily, at the point of contact between the member 49 of the U-shaped spring 48 and the rotating Contact 35, and secondarily, and inimediately after the primary break, at the point of contact between the member 71 of the U-shaped spring 48 and the contact member directly connected to the terminal 73. Likewise, when the circuit is closed, due to the rotation of the commutator, contact will first be made between the member 7l of the resilient U- shaped spring 48 and the contact member 70, and thereafter when the member 49 of the U-shaped spring drops down from the high point of the cam 32 at tooth 34, the second contact is made between the said arm 49 and the contact 35. Consequently when the circuit is opened-due to the operation of the switching mechanism-the circuit will be broken practically simultaneously at two points, thereby` very materially reducing the resulting sparking at the points of contact and consequently increasing materially the current carrying capacity of the switching mechanism.

It will be evident also from the foregoing description that sockets constructed in accordance with the teachings of this invention are made of a very few simply constructed parts which can be very compactly assembled in the limited space available in a lamp socket, and due to the simplicity of the construction of these parts the operation of the switch mechanism is exceedingly efficient and reliable.

Obviously, the invention is not limitedv to the specific embodiment thereof herein illustrated and described but is capable of many variations and other applications within the spirit and scope of the invention as set forth in the following claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. In a device of the character described, in combination, an linsulating base having a chamber, a combination ratchet and cam wheel constructed of insulating material, rotatably mounted'in said chamber, lamp contacts and circuit terminals mounted on said base, a conducting plate positioned on the cam wheel and extending substantially over -180 degrees of its surface, said combination means being serially interconnected between one of said terminals and one of said lamp contacts, andr means for operating said cam wheel, said wheel having two cams of unequal drop, whereby said conducting member, said contact plate, and said resilient nieans cooperate to alternately open and close the continuity of the lamp switch circuitr at two points.

2. In a device of the character described, in combination, an insulating base having a chamber, an insulating cam wheel rotatably mounted in said chamberl` a conducting plate on said cam wheel, a journal for said cam wheel, said journal being electrically connected to said conducting plate, circuit terminals and lamp contacts carried by said base, a rigid stationary contact member, a resilient means arranged to make and break contact with both said'stationary and said rotatable contact, said stationary and rotatable contacts, together with sa-id resilient means, being serially interconnected -between one of said circuit terminals and one of said lamp contacts, and means for rotating said cam wheel, said cam wheel being provided with cam portions of unequal drop to cause the resilient means to successively make and break contact with both said stationary and rotatable contact members. A

3. In a device of the character described, aninsulating base, a stationary switch -contact carried by said base, a cam wheel rotatably mounted on said base, a contact member carried by said cam wheel, said cam wheel having an abrupt drop at the end of said contact member and a gradual rise from said drop to the opposite end of said contact member and a lesser drop to said contact member, a resilient conducting vmember interposed between said stationary switch contact and said cam wheel for bridging across from the said stationary Contact to the contact member on the cam wheel, the drop from the end of said contact member being suliiciently great so that said conducting member cannot engage both said stationary contact and said contact wheel at the same time, and means ytending to move said conducting member bodily away from said stationary contact.

4. In a device of the character described, the combination of a base, a stationary switch contact carried by said base, a commutator rotatably mounted on said base, said commutator having a non-conducting cam terminating in a drop, said commutator having also a conducting cam terminating in a drop greater than that of the non-conducting cam, a resilient conducting memi i stationary contact, the drop at the termination of said conducting cam being sulficiently great to prevent the resilient member engaging both the stationary contact and the non-conducting cam at the same time.

5. In a device of the character described, in combination, an insulating base, a com mutator having two cams, each substantially 180 degrees in length, rotatably mounted on said base, one of said cams being of non-conducting material, and the other oi? conducting material, a resilient conducting member arranged to engage said cams, means to rotate said commutator to compress said resilient means through the action of the non-conducting cam, a stationary contact member, biasing means acting on said resilient means to disengage it from said stationary contact member, said resilient means being electrically connected with said contact member when thus compressed, the end of said non-conducting cam terminating in a drop to permit said resilient means to expand sufficiently to make contact with said conducting cam without leaving said stationary contact, whereby electrical continuity is established from said conduct-ing cam through said resilient lmeans to said stationary contact member.

said contact member, a commutator rotat-- ably mounted in said base and having two cams, each substantially 180 degrees kin length, one of said cams having a face of non-conducting material, the other cam having a face of conducting material, and means for rotating said comniutator, whereby said resilient bridging member is moved into engagement with said contact member by engagement with said iace of non-conducting material, said commutator having a drop at the end of said face oi`i non-conducting material, to permit the bridging member to expand slightly and establish electrical continuity between said Contact member and said conducting cam face, said commutator having an abrupt drop at the end of said conducting 'lia-ce to permit said bridging member to snap oil the conducting face of said commutator, said bridging member being provided with biasing means acting to disengage it from said contact member whereby contact will first be broken between said conducting face and said bridging member and immediately thereafter between said bridging member and said contact member,

7. A switch mechanism comprising a rotatable commutator having a conducting cam terminating in a relatively large drop, and a non-conducting cam terminating in a smaller dropa first contact member, and a second contact member, said irst contact member comprising a two-armed spring, one arm of which is engageable yand disengageable with respect to said cams, and the other arm of which is engageable and disengageable'with respect to said second contact, the larger drop permitting said springv contact to disengage said second contact, the smaller drop not being suiiicient to permit said spring contact to disengage said second contact.

In witness whereof, I have hereunto subscribed my name.

REUBEN B. BENJAMIN.

Images