US2629789A - Pull-operated switch - Google Patents

Description

Feb. 24, 1953 G. B. BENANDER PULL-OPERATED SWITCH Filed March l5, 1951 Tfigfz.

Invembor: George B. Benemde His Aitor-h ,Q

Patented Feb. 24, 1953 .PULL-OPERATED SWITCH George B. Benander, Oaklawn, R. I., assigner, "by

mesne assignments, to General Electric Company, a corporation of New York Application'March 13, 1951, Serial N o. 215,292

6 Claims.

My invention relates to a pull-chain-operated electric switch, and more particularly to a switch having a ratchet-operating mechanism.

This application is a continuation n part of my copending application Serial No. 109,008, led August 6, 1949, now Patent No. 2,606,258, dated August 5, 1952, and assigned to the Isame assignee as that of the present application.

Pull-operated switches commonly employ .a pull chain to operate the switch to its successive positions through a .ratchet mechanism. Such a switch has required a number of 4components including a ratchet of insulating material to drive the movable contactor and a driving connection between the pull chain and ratchet. In addition, Underwriters .Laboratory requires an insulating link in the pull chain whenever the switch is to be used in damp locations. There is an inherent possibility with such switches of the pull chain breaking inside the switch case, resulting in a short circuit.

A primary object of my invention is to provide a pull-operated lswitch with a reduced number of component parts while ,providing a mechanism of increased reliability.

Another object of my invention is to construct a pull-chain-operated switch, equally suitable for damp or dry locations, at a reduced manuiacturing cost.

A further object of my invention is to eliminate the possibility of short lcircuits within the switch due to .breakage of the pull chain.

Still another object of my invention is to provide a pull-chain-operated switch with an improved ratchet-operatingr member .having an insulating link extend-ing outside the switch `case to convert the longitudinal pull applied outside of the switch into a rotary motion for operating the contactor.

In accomplishment of the foregoing objectives, a feature of my invention consists of an improved ratchet and pull link member, formed as an integral unit from an insulating plastic material, such as for example a nylon, for a pulloperated switch. This member, mounted coaxially with a rotary contactor of the switch, has a ratchet face to provide a one-way driving engagement with the rotary contactor, and includes an elongated flexible portion extending outside the switch housing which serves `as a pull link to operate the switch. The pull link has a transverse cross-section that provides a major and a minor axis with Lprovision being made for the flexing of this link relative to the major axis.

(Cl. ZIN-51.15)

My 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.

Referring to the drawing., Fig. 1 is a front elevation of my improved socket and switch assembly, partially in section, with a portion of the switch housing removed; Fig. 2 is a cross-sectional view, in elevation, taken at right angles to the view shown by Fig. l; Fig. y3 is a partial view of 'the socket switch shown by Fig. 1 with the switch operating mechanism in a diierent position; Fig. 4 is an exploded view in perspec tive of the component parts making up this 53 socket and switch assembly; while Fig. 5 is a cross-sectional view of a transverse section of the pull link.

The embodiment of my invention illustrated by the drawing is in the form of a socket and pull-chain-operated switch. The switch and socket assembly is enclosed within an insulating housing of generally cylindrical conguration, which is formed in two parts I and 2 from a material such as a .molded plastic. Thus the semi-cylindrical portion 2 of the vhousing may be removed .for assembly. A threaded fastening device 3 mounted in body portion I engages body portion 2, and likewise a similar threaded element mounted in body portion 2 is engageable in the hole 4 in body portion I in order to hold these two separable portions of the case in assembled relation. The socket portion of this assembly includes a cylindrical member 5 with a rolled thread to receive a threaded Abase of an electric lamp or similar device. As is conventional in socket construction, cylindrical member 5 is vof velectrical conducting material to form one of the socket contacts. The other socket contact is formed by a button 6 centrally mounted within the socket. A cap 'I is adapted to fit over the upper end of the `case formed by members I and 2, as best shown by Figs. 1 and 2. The entire assembly may be supported from a wall or ceiling, and for this purpose cap 'l is apertured to receive a supporting member, such as tube 8. A set screw 9, threaded through the neck portion of cap l, engages tube 8. .An aperture If) in cap 1 permits the entrance 'of the electrical supply lines for attachment to terminals Ii and I2. IScrews I3 and I4 provide a means for attaching such electrical conductors to these terminals. Part I of the switch housing includes terminal housing 32 and 33 for receiving terminals i I and I2 respectively and their corresponding terminal screws I3 and I4.

The cylindrical socket member 5 and central contact Ei are electrically connected through the switching mechanism to the terminals I I and I2. In order to mount the cylindrical member 5 within the housing, it is provided with a laterally extending flange I5 around its lower edge, and this ilange is slotted at one or more points as at I6. The socket housing is provided with an annular groove I1 co-operable with ange I5, and this groove is interrupted at spaced points to correi spond with slots I6. By this construction the cylindrical member 5 is prevented from any longitudinal or rotary movement with respect to the housing. Cylindrical member' 5 includes an inturned lip I8, as shown by Fig. 4, which provides a connecting point for a terminal strip I9. Strip I9 may be riveted or otherwise rmly secured to lip I8, and an aoerture 2B at the point of connection between these two parts is adapted to Iit over threaded fastening device 3 to anchor strip I9 in position. Strip I9 thus forms a through electrical connection from terminal I I to the cylindrical socket member 5.

The central contact 6 of the socket is electrically connected to terminal I2 through a movable contact of the switching mechanism. Integrally formed with contact 6 is an arcuate shaped portion 2I which provides one of the xed contact members for the switch. The switch and socket housing formed by members I and 2 is provided with a wall 22 to divide the socket portion of this device from the chamber containing the switching elements. As shown by Fig. 4, the portion of wall 22 which forms part of the housing portion I is slotted and grooved as at 23 to receive laterally projecting ears 24 on the neck portion between central contact 5 and the arcuate contact 2l. As best shown by Fig. 4, a second arcuate member 25 forms the other xed contact for the switch assembly. This arcuate member 25 is connected by a terminal strip 25 to terminal I2.

Fixed contacts 2I and 25 of this switch assembly are mounted in the switch housing I in a manner to provide a snap action for the switch. For this purpose, a post or cylindrical member 21 forms a part of and extends inwardly within the switch housing` portion I. The end of post 21 is shaped to provide a plurality of sloping arcuate surfaces arranged around the end of the post in stepped relation. These arcuate, sloping, and stepped surfaces are best shown by 4 surfaces 2B, 29, 30, and 3|. Arcuate xed contact 2| overlies the surface 3E) and contact 25 over-lies surface 2B. leaving surfaces 29 and 3l without contacts for the off position of the switch.

Cooperating with fixed contact members 2| and 25 is a rotary contact member 34, the details of which are most clearly illustrated by Fig. 4:. Rotary contactor 34 is centrally apertured at 35 so that it may be mounted on the end of post 2l to rotate to its various contact positions. Rotary contact element 34 includes laterally projecting arms 25, 31, 38, and 39, which serve in connection with the driving of this contactor in its rotarv motion. The arr-ns 21 and ."9 carry the contact feet 4G and 4I which are shaped to facilitate rotation over the arcuate surfaces on the end of post 21 and to make contact with xed contact members 2I and 25.

To drive rotary contactor 24, a combined ratchet and pull link member 42 is employed. The details of member 42 are most clearly illustrated by Fig. 4. This member is fabricated from an insulating material since it is in direct engagement with the electrically conducting rotary contactor. For the purpose of providing a one-way drive for contactor 34, member 42 has a ratchet face with a plurality of ratchet protuberances 43, 44, 45, and 46. These protuberances co-operate with the laterally projecting arms of the rotary contacter so that upon rotation of meniber 42 in one direction, rotary contactor 34 is also rotated. However, rotation of member 42 in the opposite direction does not drive the rotary contactor because of the sloping surfaces of this series of protuberances. The face of member 42 opposite the ratchet face has projecting therefrom a pin 41 which co-operates with a resilient means, to be described later, to return the ratchet member to its initial position after each rotation. So that ratchet member 42 :lay be rotated from a point outside the switch housing, it includes a radially extending arm 43, the arm 48 extends into an elongated flexible link 49 having sufficient length to extend outside of the switch housing as shown by Fig. 1. Theiiexible link 49 is constructed to provide a major and a minor axis. In a preferred embodiment, as shown in Fig. 5, this cross-section is oval shaped to provide for the exing of the link about the major axis 49a. It is understood that this invention is not to be limited to this particular improvement, but that it has been chosen to illustrate one example of the cross-section having a major and a minor axis. With the cross-section formed in accordance with these requirements, a link of improved flexibility is provided thereby improving the operation of the switch without sacrificing the strength of the pull link member. The housing has an aperture 5I) with rounded edges through which link 49 may extend. The outer extremity of this flexible elongated link 49 has a ball 59 to provide a means for attachment to a pull chain 5| through a connecting link 52. It will be understood, of course, that a pull cord or other means might be connected to link 49 to extend to a more convenient point of operation; or the link 49 itself may be formed with additional length so that it would hang down to a convenient point for switch operation. A second radially extending arm 48a forming part of member 42 co-operates with the elongated link 49 in order to increase the torque applied tending to rotate member 42 upon application of the initial force to operate the switch. Member 42 is also centrally apertured at 35d so that it may be mounted coaxially with` rotary contactor 34.

While there may be a number of materials from which the ratchet and pull link member 42 can be made, I nd it preferable to employ a synthetic resin capable of being molded to the desired shape. As an example, super polyamides, commonly available under the name nylon, are particularly well suited since such resins can be economically injection molded from a powder to produce a long-wearing and strong member free from atmospheric influences, while still having adequate resiliency and strength to form the flexible link portion 49. The plastic material employed must, of course, be an electric insulator and have a relatively high softening temperature for this application, in addition to having the characteristics of strength and resiliency. In particular, I have found that Du Pont nylon No. FM-lOOOl is Well suited to these particular requirements, although other nylons and plastic compounds may be employed.

The rotary contactor 34 and the pull link and ratchet member 42 are held in assembled relation with respect to the end of post 21 and the xed contacts of the switch by means of pin 53.

Pin 53 is threaded at 54 and these threads cooperate with an internally-threaded aperture 55 centrally .located in the end of post 21 of the switch housing. Both contactor 34 and ratchet member 42 `are freely rotatable about this pin so that the contactor may be rotated to its contact positions upon rotation in a driving direction of ratchet member 42. A resilient means 56, here shown as a. helical spring, is provided to engage pin 41 on ratchet member 42 for an automatic return of the ratchet member to its initial position after each operation of the switch. Pin 53 has a square head 51 to engage the side walls of spring retainer 58. The retainer 58 is thus nonrotatably associated with pin 53, and it includes a tongue 59 to engage one end of spring 56 to prevent the spring from rotating when it is installed in operative position. Spring 55 is installed in this assembly so that it is at all times under slight torsional stress. This insures that the ratchet member 42 will always be returned to its initial position after an operation of the Switch.

Spring 56 is also under compression at all times in order to force the ratchet member 42 into engaging relation with the rotary contactor 34, and to rforce rotary contactor 34 into firm contact with the fixed contacts 2| and 25 as they are positioned on the end of the post 21.

The method of assembly of this socket and switch will be understood by a reference to Fig. 4. The cylindrical socket member 5 with its terminal strip I9 riveted thereto is first placed in position in the half portion of the housing. Screw 3 projects through the aperture 20 and the flange |5 lies within the groove l1 of the housing to properly position the cylindrical member 5. Central contact 6 and its arcuate portion 2| may next be installed with arcuate portion 2| overlying and in contact with surface 3D on the end of post 21. The other Xed contact as formed by the arcuate portion along with its corresponding terminal strip 26 and terminal l2 is placed in position with the arcuate portion 25 overlying and in contact with surface 28 on post 21. It is thus seen that the two fixed contacts are arranged in diametrically opposite relation, and the sloping surfaces 29 and 3| present only the insulating material from which the switch housing and post 21 are fabricated. Therefore, when the rotary contactor 34 is placed in position on the end of post 21 its contact feet 40 and 4| may rest either on the fixed contacts 2| and 25 or on the insulating surfaces 29 and 3|, corresponding respectively to the on and off positions of the switch. With the rotary contactor in position the ratchet member 42 is placed over the rotary contactor 34 with its ratchet face in contact with the laterally extending arms of the rotary contactor. Pin 53 with its spring l56 and spring re tainer 58 is next secured in position rotatably supporting the ratchet member 42 and rotary contactor 34 in assembled relation on the end of post 21. To complete the assembly it is merely necessary to attach the other` half 2 of the switch and socket housing to the .housing half and attach cap 1 to the completed assembly,

To operate this device after the socket assembly has been attached to a suitable support and the electricalsupply line has been connected to terminals and I2 by means of the terminal screws I3 and I4, it is merely necessary to pull on the chain 5| to throw the switch to its next position. In the particular embodiment illustrated the switch has only two positions, that is on or off. It is to be understood, however, that this same type of assembly could be employed with a multi-position switch by increasing the number of steps and contact points for one complete revolution for the rotary contactor. After the force has been applied to the chain 5| to throw the switch to its next position, the chain is then released and the switch is automatically reset for the next switch operation. The force applied to the pull chain is transmitted through the connecting link 49 to provide a torque through the arms 48 and 48a to rotate ratchet member 42. Since the combined ratchet and pull link member is made of a plastic which is also an insulating material, danger is eliminated of a short circuit occurring within the switch through pull link 49. The ratchet protuberances on the ratchet face of member 42 engage the laterally extending arms of the rotary contactor 34 to cause it to rotate one step. During this rotation the contact feet 4D and 4| of the rotary contactor ride up the sloping arcuate surfaces formed by either the faces 29 and 3| of post 2.1 of the housing or on the similar surfaces formed by the xed contacts 2| and 25. When the cone tact feet have passed over the highest point on these sloping surfaces, the rotary contact element, under the influence of the compression of spring 56, snaps down to the next contact position. Thus each operation of the switch results in a snap action to quickly make or break the electrical circuit.

From the above description, it can be seen that l have provided a new and improved `socket and switch assembly in which the number of component parts making up the assembly have been minimized. Such a construction permits increased economy in manufacture of the ccmpleted article. At the same time, due to the simplicity of the operating parts, a high degree of reliability is achieved. In particular, a greatly improved means is provided for driving the movable contact member of the switching assembly which includes as an integral part thereof an insulating link extending outside the switch housing.

While the present invention has been described by reference to a particular embodiment thereof, it will be understood that numerous modifications may be made by those skilled in the art without actually departing from the invention. I, therefore, aim in the appended claims to cover all such equivalent variations as come within the true spirit and scope of the foregoing disclosure.

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

1. En a. pull operated switch having a rotary contactor for making and breaking the circuit through fixed contacts, a ratchet and pull link member for operating said rotary contactor in steps, end a pin forming an axis about which said member and said contactor rotate, said member being integrally formed from nylon and comprising a ratchet face providing a one-way drive for rotating the contactor, a protuberance on the face thereof opposite said ratchet face engageable with a resilient means to return said member to its initial position independently of the contactor after each operation of the switch, a radially extending arm, an elongated flexible portion extending from the end of said arm forming the pull link for the switch, said link having a transverse cross-section providing a major and a minor axis with said link being positioned relative to said switch to permit the flexing of said link relative to the major axis of its cross section, and a second radially extending arm forming a bearing for said pull link to increase the torque resulting from a given pull on said link during initial rotary movement.

2. A socket and pull switch assembly comprising an insulating case for the assembly, a socket within said case having socket contacts, terminals supported by said case for connecting said socket contacts to an electrical supply line, and a switch mechanism within said case for making and breaking the circuit through said socket contacts, said switch mechanism comprising a post forming a part of and extending inwardly within said case, the end of said post having a plurality of arcuate sloping surfaces in stepped relation, a fixed Contact associated with one of said terminals overlying one of said surfaces, a second xed contact associated with one of said socket contacts overlying a second of said surfaces, a rotatable contactor made of electrical conducting material having radially extending arms including foot portions engageable with said fixed contacts to make and break the circuit through said fixed contacts upon rotation, an integral nylon ratchet and pull link member mounted coaxially with said rotatable contactor with the ratchet face of said member engaging said arms to eifect the rotation of said rotary contactor through one rotary step, said link having a transverse crosssection providing a major and a minor axis with said link being positioned relative to said switch to permit the ilexing of said link relative to the major axis of its cross-section, and resilient means returning said member to its initial position without movingr said rotary contactor.

3`. A socket and pull switch assembly comprising an insulatingcase for the assembly, a socket within said case having socket contacts, terminals supported by said case for connecting said socket contacts to an electrical supply line, and a switch mechanism Within said case for making and breaking the circuit through said socket contacts, said switch mechanism comprising spaced fixed contacts, a rotatable bridging member made of electrical conducting material engageable with said xed contacts to make and break a circuit r between said fixed contacts upon the rotation of said bridging member through successive rotary steps, an integral nylon ratchet and pull link member mounted coaxially with said rotatable bridging member with the ratchet face of said ratchet member engaging said bridging member to eilect the rotation thereof through one rotary step, said link having a transverse cross-section providing a major and a minor axis with said link being positioned relative to said switch to permit the flexing of said link relative to the major axis of its cross-section, and a resilient means returning said ratchet member to its initial position without moving said rotary bridging member.

4. In a pull-operated switch having co-operating movable and fixed contacts, a ratchet and pull link member for operating said movable contactor in steps, comprising a relatively rigid ratchet disc and a flexible insulating link extending from the edge of said disc for rotating the disc, said link having a transverse cross-section providing a major and a minor axis with said link being positioned relative to said switch to permit the flexing of said link relative to the major axis of its cross-section, a radially extending arm forming a bearing for said pull link to increase the torque resulting from a given pull on said link during initial rotary movement, said disc, said link and said arm being integrally molded from a super polyamide.

5. A rotary switch operable to successive positions by repetitive longitudinal force comprising a plurality of fixed contact positions including an olf position, a rotary contactor made of electrically conducting material having feet adapted to sweep over said xed contact positions for making and interrupting electrical circuits, a combined driving member and pull link for operating said rotary contactor comprising a super polyamide molded to form integrally a rigid ratchet faced element engageable with said rotary contactor for operating the same and an elongated ilexible pull link element for rotating said rigid ratchet faced element whereby longitudinal force which is applied to said pull link rotates said rigid ratchet faced element to move said rotary contactor one step, said elongated flexible pull link element having a transverse cross section providing a major and a minor axis with said link being positioned relative to said switch to permit the flexing of said link relative to the major axis of its cross section, and resilient means to return said combined member to its initial position independently of said contactor after each operation of the switch.

6, In a pull-operated switch having cooperating rotatable and xed contacts, a combined driving member and pull link for operating said rotatable contacts comprising a super polyamide molded to form integrally a rigid ratchet faced element engageable with said rotatable contacts for operating the same and an elongated flexible pull link element for rotating said rigid ratchet faced element, said elongated exible pull link element having a transverse cross section providing a major and a minor axis with said link being positioned relative to said rigid ratchet faced element to permit the flexing of said link relative to the major axis of its cross section` GEORGE Bi. BENANDER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,102,639 Benjamin July 7, 1914 1,918,726 Weber July 18, 1933 2,169,868 Benander Aug. 15, 1939

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