US 3114024 A
Description (OCR text may contain errors)
R. S. TILLSON Dec. 10, 1963 ENCLOSED MULTI-POLE SWITCH WITH REMOVABLE CONTACT CARRIER 3 Sheets-Sheet 1 Original Filed Dec. 4, 1959 6 2 I 2 u a 9 3 G v 6 m 1 2 8 2 2 w r mu 0 a 3 w v .|x|| 4 INVENTOR. ROBERT S.TILLSON BY Dec. 10, 1963 R. s. TILLSON 3,114,024
ENCLOSED MULTI-PQLE SWITCH WITH REMOVABLE CONTACT CARRIER Original Filed Dec. 4, 1959 I 3 Sheets-Sheet 2 INVENTOR.
ROBERT S. |LLSON Dec. 10, 1963 R. s. TILLSON 3,114,024
ENCLOSED MULTI-POLE SWITCH WITH REMOVABLE CONTACT CARRIER Original Filed Dec. 4, 1959 3 Sheets-Sheet 3 i 39 54 A I 26 '4 r- 13 i i /j a mmvroa R OBERT S. -IILLSON United States Patent 3,114,024 ENCLOSED MULTl-PGLE SWETCH Wl'll-l REMOVABLE QGNTAQT CARRIER Robert S. Tillson, Bristol, Conn, assignor to General Electric Company, a corporation of New York Uriginal application Dec. 4, 1959, Ser. No. 857,384, now Patent No. 3,041,432, dated June 26, N62. Divided and this application May 18, 1962, Ser. N06 195,774
2 Claims. (Cl. 206-168) My invention relates to electric switches of the type which are enclosed in an outer enclosure and operated by manually operable means accessible externally of the enclosure. This application is a division of my co-pending application Serial Number 857,384, filed December 4, 1959, and assigned to the same assignee as the present invention. More particularly, the present invention relates to switches of the type including a base and an elongated contact shaft or rotor, carrying a plurality of movable contact members which are adapted to bridge or interconnect pairs of stationary contacts. Such switches have advantages over knife switch types of switches, in which a plurality of movable blades or contact arms are hinged or pivoted about a fixed pivot at one end, in that they provide a double-break action instead of only a single breaker. By double-break it is meant that the current in each conductive path or pole is broken at two serially related points as compared with single breal in which the path is broken at only one point. Such switches also have advantages over the type in which a plurality of bridging contact members are moved rectilinearly to bridge a pair of stationary contacts, in that they provide a pronounced wiping action in the switching operation which maintains a good contact surface.
According to the prior art, however, contact-rotor type switches have not been wide.y used because of various difiiculties in their manufacture, operation ad mtaintenance. Thus in prior art switches of this type, it has been relatively difficult to remove and replace contacts. in rotor switches of the type including contacts of the l: ifeswitch design, loss of contact-pressure is likely to occur, which interferes with proper operation. This occurs because such contact-pressure depends upon the resilience of the contact-jaws of the socket member, which is dii'ilcult to maintain at a desired high level, especially without causing binding on tne movable switch blade.
It is an object. of the present invention to provide an electric switch of the double-break contact-rotor type havi. g dependable and lasting contact pressure. i
It is another object of the invention to provide a switch of this type in which the movable contacts may be readily removed and replaced to facilitate inspection and/or replacement.
it is a further object of the invention to provide a witch of the double-break rotor type in which alignment of stationary contact surfaces is not critical to satisfactory operation.
A still further object ofthe invention is to provide a switch of this type in which contact pressure of each of the movable contact members will be maintained equally on each of the members of the pair of stationary contacts which it bridges.
it is another object of the invention to provide an enclosed electric switch in which the movable contacts are readily visible in the oil position upon opening of the outer enclosure.
Another important object of the invention is to provide an electric switch in which the number of electrical con nections in each conductive path or pole therethrough is reduced to a minimum.
Additional obiects of the invention will in part be pointed out, and in part become obvious, from the follow- 2 ing description of construction and operation of a particular embodiment.
In accordance with the invention in one form, an electric switch is provided including a base of molded insulating material. An insulating rotor is supported for rotation in the base, and a plurality of bridging switch members are provided, each of which is independently and resilient- 1y supported in the insulating rotor. A pair of stationary contact members is provided foreach of the bridging switch members. Each contact member has a cam surface portion arranged so that when the bridging switch mernber engages the stationary contact, continued rotation of the rotor cams each of the switch members laterally against its contact pressure spring.
in accordance with one aspect of the invention, the insula ng rotor is movable to an on position and an off position, and also to a third position in which the rotor may be removed from the insulating base. The base is, furthermore, mounted in an enclosure and the rotor is releasably connected to an operating mechanism carried by the enclosure, which mechanism limits movement of the rotor to the off and on positions only.
The invention will be more fully understood from'the following detailed description, and its scope will be pointed out in the appended claims.
in the drawings:
FXGURE l is a front elevation view of an electric switch in accordance with the invention, the cover of the enclosure being open and partly broken away;
2 is an exploded view of the terminal and contact portions of one pole of the switch of FlGURE 1;
3 is an exploded view in perspective of the rotor assembly of the switch of FIGURE 1;
3A is an enlarged View of a portion of the rotor assembly of FIGURE 3;
FIGURE 4 is a fragmentary elevational view of the switch of FEGURE 1 taken generally on the line 44 of FEGURE l;
FLJURE 5 is a perspective view of a modified form of combination terminal and contact member.
in the drawings, the invention is shown as embodied in an electric switch including a generally rectangular enclosure ltl. Mounted within the enclosure and on the wall thereof is a main insulating base" 11 and a second, smaller, 1 lded insulating base 12. The base 11 is held in place by means of mounting screws Ill, and the base 12 is held in place by means of mounting screws 12. The insulating base 11 serves as a switch base, and has a Contact rotor 13 rotatably supported at one end 313A on the insulating base in a manner to be described. The opposite end 133 is not supported on the base ll, but projects beyond the side of the base at the right as viewed, and into an aperture in the operating member 14. The end 13B and the aperture in member 14 are of corresponding non-circular configuration. The operating membe: 14 is supported on a pivot pin l5 in the side wall of the enclosure lil substantially aligned with the axis of the rotor 13. The member 14 connected by of a link it; to a manually operable handle member 17 pivotaliy supported on a pivot pin lb, also in the side wall of the enclosure ill. The end 13A of the rotor 13 is rotatably supported by two opposed, displaced, generally semicircular, upper and lower bearing surfaces 22'} and 21, at the left-hand end of the rotor, as shown particularly in FIGURE 3.
The mounting of the rotor 13 as described affords important advantages. Since the rotor is jou-rnalled on the base ll only at the end 13A, small variations in the positioning of the switch base ill in the enclosure do not interfere with proper operation. The rotor '13, in other words, can vary slightly in its position with respect to the base ll to compensate for variations in the relative positions of the bearings 20, 21 and the pivot 15 of the member 14. As will be further described, the functioning of the contact members is not adversely affected by such variations in positioning of the rotor.
A set of three line-terminal contact members 23 are mounted on the base 11 by suitable means, such as by screws 24, and each of the contacts 23 carries a wire connector 25 on an extension thereof. (See FIG. 2.) The construction of the line contact assembly is shown particularly at the right-hand portion of the exploded perspective view of FIGURE 2.
A set of fuse-terminal contacts 26 are likewise supported on the insulating base 11, by suitable means, such as by screws 27. Each of the contacts 26 includes a resilient spring clip member 28 attached thereto by means of a rivet 29. The spring clip 28 is spaced closely from a vertical wall portion of the contact 26 for the purpose of receiving the blade of a fuse member 34.
It will be observed from FIGURE 1 that the contact portion of each of the terminals 26 serves a dual purpose. Thus one face of the vertical portion of the tcrnn nal serves as a contact for co -action with the movable contacts 39 in a particular manner, to be described. At the same time, the opposite face of this same portion of the terminal serves as a contact for the blade of the fuse 34. The necessity for a separate fuse-clip or a separate stationary contact is thereby eliminated.
A set of three load terminal members 30 are mounted on the secondary insulating base 12 by suitable means such as by screws 31. Each of the load terminals 30 comprises a generally L-shaped conductive member having an extension upon which a load wire connector 32 is mounted. A generally L-shaped spring clip member 33 is mounted adjacent each of the load terminals as and includes a portion spaced closely trom the vertical portion of the load terminals for the purpose of receiving the opposite end portion of the fuse 34. The spring clip member 33 includes a portion extending through an opening 35 in the molded base 12 and has a portion extending under the base 12 and attached thereto by the screw 3-1 which also holds the terminal 3b in position, all as shown in FIGURE 12.
The base 12 also includes an integral extension 12A on which are mounted a plurality of wire connectors 37 for the purpose of facilitating connection of neutral conductors, not shown.
The rotor assembly is shown particularly in the perspective view of FIGURE 3. As shown in this figure, the rotor assembly includes an insulating rotor 13 and a plurality of bridging contact blades 33 corresponding in number and position to the pairs of stationary contacts 23, 26.
Each of the contact blades 33 includes a pair ot wide,
flat contact end portions 39 at the opposite ends thereof, each provided with a projecting arcing tip 39', leaving a restricted central portion 42* which is circular in cross section. When assembled, each of the contact blades 38 is resiliently biased to a normal position by means of a flat leaf spring 41 having a bowed configuration and having one end 41 bent inwardly and adapted to seat in the shallow recess 42, in one of the contact ends 39. The insulating rotor 13 has three enlarged hub portions 43, each of which has an aperture 44 therethrough. The configuration of the apertures 44 is shown particularly in FIGURE 3A which also includes a showing of the section of the contact blade and biasing spring. The aperture 4-4 includes an enlarged portion 45 and a reduced portion 4s. The portions 44 and 45 are dimensioned so as to permit the insertion of the contact blade 33 when the blade portions thereof are maintained in a horizontal position. Following insertion of the contact blades this marine, the blade may be rotated 90 degrees, in which position the shoulders 4d of the contact portions retain the contact blade in position by engagement with the rotor.
The contact blade 38 is resiliently maintained in this assembled position by means of the biasing contact spring 41 which is slid into position, being received in the porion 45 of the aperture 44 and having its ends bearing against the contact portions of the contact blade 33, there by biasing the central cylindrical portion 40 of the contact blade against the curved shoulders 48 in the aperture 44.
The contact spring 41 is maintained in fiatwise engagement with the end wall of the portion 45 of the recess44 and has its opposite ends in engagement with the contact port-ions 69 of the contact blade. The result is that it maintains the contact blade 38 resiliently in the assembled condition illustrated, in which the major plane of the contact surface 39 is perpendicular to the axis of the rotor 13. At the same time, each of the blades 38 is permitted to rotate about the axis of the central portion 49 a small amount, and in addition, it is permitted to move a small amount in about an axis perpendicular to the axis of the rotor 13. In other words, while the contact blades each restrained from any movement about the axis of the rotor 13, each is permitted to move about other two axes in space extending perpendicular to the axis of the rotor. In addition, each of the contact blades 38 is permitted to move bodily and rectilinearly in the direction of the axis of the rotor 13.
Each of the contact blades 38 also includes a raised or embossed contact surface 39A, see FIGURE 1, located generally centrally of the contact portions 39.
The insulating rotor 13 includes a pair of flanges 49 at intermediate points, for the purpose of increasing the electrical oversurface clearance between adjacent contact members.
In addition, the rotor 13 includes a generally oblong bearing member 50 at an intermediate point. The bearing flange 50 is adapted to bear against the projections 51 of the base 11 during normal operation of the rotor between its off and 011" positions. This engagement prevents any movement of the insulating rotor axially toward the right as viewed at such times. During inser tion and removal of the rotor, however, the rotor is rotated degrees with respect to its normal on position, to the remove position R indicated in FIGURE 4 which permits it to pass between the projections 51, allowing the rotor 13 to be moved axially a short distance to the right, to permit the left end to clear the bearing surface 20.
In normal use, the rotor 13 is prevented from rotating a full 90 degrees away from the on position by means of its engagement with the operating member 14 of the operating mechanism. The rotor is disengaged from'the operating member 14 by moving the entire switch assembly to the left within the enclosure 10, after'rernoval of the mounting screws 11'. The rotor assembly may there fore be easily inserted and removed in the switch base 11, and no separate fastening or retaining members are required for this purpose.
Each of the stationary contacts 23 and 26 includes a generally planar main contact portion which has one portion 23A and 26A respectively, extending at an angle to the plane of the main portion and which act as a cam surface, along which the movable contacts ride as the rotor is rotated. This action forces the contact blades 38 to the right as viewed in FIGURE 1,'compressing the contact springs 41.
The action of the contact springs 41 against the rotor 13 is such as to urge the rotor 13 for axial movement to the right as viewed in FIGURE 1. Such motion is prevented, however, as described above by the engagement of the bearing flange 59 with the stops 51 of the base 11. An effective contact pressure is therefore maintained, of the movable contact against the stationary contacts. It will also be observed that because of the mounting of the movable contact members, as described above, they are enabled to adjust themselves resiliently to the stationary contacts, and therefore no difficult alignment problems are presented in the manufacture and maintenance of the switch. This is to be contrasted to switch constructions which involve moving a switch blade in between a pair of closely spaced contact jaws at each end of a bridging blade, in which constructions alignment problems are critical.
Moreover, the use of a bridging contact blade which resiliently engages only a single contact surface at each end and is resili ntly biased by spring means at its center point overcomes the problems involved in maintaining suilicient contact pressure which are commonly encountered with the spaced contact jaw types of construction.
It will be observed, moreover, that since the engagement of the bearing flange 5i; with the projections 51 prevents axial movement of the rotor to the right during switching operation, the contact pressure of each bridging contact pole is substantially independent of the contact pressure at any other pole. Thus, for example, any one of the bridging contact members 33 may be omitted to provide a two-pole switch, without aifecting the contact pressure developed by the remaining two poles.
For the purpose of aiding in the cooling and extin guishing of arcs drawn by the contacts, there is furthermore provided an arc shield 53 for each of the stationary contacts 23 and 26, and retained on the insulating base 11 by means of screws 5'4. Each of the arc shields 53 is of generally U-shaped cross section and includes a plurality of open slots 5% in the bight portion thereof. The are shield members are preferably constructed of ferromagnetic material such, for example, as steel.
The insulating base 12 also includes an extension 123 provided with a pair of upstanding barrier portions 56 which serve to shield the fuses 34 from each other. The base ll has a similar extension 113, including similar barrier portions 63.
In FIGURE 5 there is shown a modified form of stationary load contact assembly comprising a stationary load contact member 58 having a generally planar contact portion 5i? and a cam portion 59A and an integral fuse retaining portion 66. For the purpose of retaining a cylindrical type of fuse ferrule in position against the portion 6% there is provided a resilient spring clip member 61 attached to the contact portion 58 by suitable means such as by a rivet 62. It will be understood that when fuses of the ferrule type are used as contrasted to the type of fuse having a blade type terminal, the retaining means mounted on the insulating block 12 would also be changed to correspond to the type shown in FIGURE 5.
While I have shown only one particular embodiment of the invention, it will be readily apparent that many modifications thereof may be made by those skilled in the art, and I therefore intend by the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.
What I claim as new and desire to secure by Letters Patent of the United States is: I
1. An electric switch comprising a support, an insulat ing base mounted on said support, a plurality of stationary contacts mounted on said insulating base in spaced apart relation, a contact rotor of insulating material rotatably supported on said insulating base, a plurality of relatively movable contacts carried by said insulating rotor for contacting said stationary contacts respectively, retaining means carried by said base overlying an end portion of said insulating rotor, said rotor being axially retractable from said retaining means when said rotor is rotated to a predetermined position, means preventing axial movement of said rotor when said rotor is in a position other than said predetermined position, operating mechanism carried by said support for operating said rotor, said operating mechanism preventing movement of said rotor to said predetermined position when connected thereto, said insulating base being movable to disconnect said rotor from said operating mechanism to permit movement of said rotor to said predetermined position.
2. An enclosed electric switch comprising a generally box-like enclosure having a back Wall and upstanding side walls, an electric switch unit including an insulating base removably mounted on said back wall, means for operating said switch unit between open and closed circuit conditions comprising an insulating rotor, retaining means carried by said base overlying an end portion of said rotor for retaining said rotor on said base, said rotor being removable from said base by initial axial movement to disengage said rotor from said retaining means, operating mechanism carried by a side wall of said enclosure for operating said insulating rotor, said insulating rotor normally being prevented from axial movement by its engagement with said operating mechanism, whereby to prevent removal of said insulating rotor from said base while said switch unit is in said mounted position, said operating mechanism also preventing rotative movement of said contact rotor beyond a predetermined amount, means carried by said insulating rotor and slidably engageable with stop means carried by said insulating base for preventing axial movement of said rotor during a predetermined portion of its rotational movement.
No references cited.