US2841672A

US2841672A - Electric switch construction

Info

Publication number: US2841672A
Application number: US522923A
Authority: US
Inventors: Peder B Hoye
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-07-19
Filing date: 1955-07-19
Publication date: 1958-07-01
Anticipated expiration: 1975-07-01

Description

July 1, 1958 P. B. HOYE ELECTRIC SWITCH CONSTRUCTION 4 Sheets-Sheet 1 Filed July 19, 1955 INVENTOR.

, PEDER 5.14am BY W 7 53M?- y 1958 P. B. HOYE ELECTRIC SWITCH CONSTRUCTION 4 Sheets-Sheet '2 Filed July 19, 1955 INVEN TOR. PEDER B. HOYE July 1, 1958 P. B. HOYE 2,341,572

ELECTRIC SWITCH CONSTRUCTION Filed July 19, 1955 4 Sheets-Sheet 3 I] R 5 9 ll Q1 Y a I m 0 m H. m H? kw E a av w R I E fi w a Q P m j w J W b fi 5 C M w QM, MN Wm. 1- C NR N. M Lv m I NW N WW 1A\/ m Q a v N +h mw & N L N 3 NW m ml aw m, H a M Q w u h P. B. HOYE ELECTRIC SWITCH CONSTRUCTION July 1, 1958 4 Sheets-Sheet 4 Filed July 19, 1955 Fig/0 INVEN TOR.

PEDEE B. HOYE United States Patent ELECTRIC SWITCH CONSTRUCTION Peder B. Hoye, Maywood, Ill.

Application July 19, 1955, Serial No. 522,923

9 Claims. (Cl. 200-163) This invention relates generally to electric switch constructions, and more specifically to switches of the type shown and described in my Letters Patent No. 2,229,504, issued January 21, 1941, and entitled Switch Construction.

The electric switch constructions shown in my noted Letters Patent, while very eflicient in operation, are relatively expensive to manufacture. The one-piece frame and movable shelf shown therein must be accurately made with all insulator mounting surfaces fiat and parallel to each other to provide alignment and proper seating of the contacts and to avoid binding during operation of the switch. Further, most of the elements within the one-piece frame must be assembled piece by piece by an assembler working within the frame. Additionally, due to the construction shown therein, the necessary alignment of the various members must be done with extreme care and skill, and the elements of another identical switch cannot be easily interchanged without a major realignw ment of the various members.

These switch constructions as they are further known in the art generally require a great many screws and nuts for the assembly of the component parts, which tends to increase their cost and reduce their reliability due to possible failures of the fasteners from vibration, fatigue or temperature changes. A loosened fastener in such a construction may become a real hazard, not only in the probability of causing a misalignment of the loosened conductor parts of the switch and a resulting thermal failure, but also in the possible shorting of the insulation through the loosened or displaced fastener to cause a dielectric failure.

Further, these switch constructions and the one-piece frame shown in my noted patent generally permit only a limited viewing of the open air gap and the position of the contacts. A clear view of the air gap and the contacts is desirable, particularly where the switch is located at a considerable distance from a remote control operating mechanism.

It is an important object of this invention to provide an electric switch construction of the type shown in my noted patent of improved reliability, in which the amount of skill and care required in the manufacturing of the device is greatly reduced, in which the cost of the switch construction is considerably reduced, and in which the servicing and interchange of parts thereof in the field is greatly facilitated.

It is another important object of this invention to provide a switch construction of the noted type in which the individual insulators are positively and permanently fastened to their respective supports.

Another object of this invention is the provision of suitable fastening or mounting means that will permit a per manent bonding of the insulators to their rough and unfinished supports with the conductors carried by the insulators accurately located relative to each other. A feature of these fastening means is the tolerating or compensating for normal variations in dimension of the rough 2,841,672 Patented July 1, 1958 and unfinished cast or fabricated supports to permit the accurate alignment.

Another object of the present invention is the provision in an electric switch construction of an insert which is permanently bonded in a movable porcelain bushing which will provide accurately located retaining surfaces for a contact sleeve carried by the bushing.

Another object of the present invention is the provision in a switch of the noted type of positive non-friction retaining means for a contact sleeve which will positively retain the contact sleeve in a movable insulator bushing in cooperation with associated retaining surfaces and to also permit a slight and controlled amount of lateral self-alignment of the contact sleeve in its mounting.

A further object of the present invention is to provide in a switch of the noted type a direct and permanent bonding of a movable or operating porcelain insulator to a movable shelf wherein the insulator carries a sleeve contactwhich is retained therein by non-friction retaining means and wherein the insulator is positioned relative to the shelf so that no tension forces are produced in the insulator when the insulator is moved in either direction to cause cooperation between the contact sleeve and the stationary contacts of the switch.

It is another important object of this invention to provide a supporting frame structure which is formed as a U-shaped, one-piece bracket and which has a shelf movably mounted thereto and in which the further mounting of the remainder of the switch construction thereto is simple, whereby assembling or servicing and replacement of the switch in a shop or in the field may be easily done.

Another object of the present invention is to provide an electric switch construction wherein regular manufacturing tolerances may be used and wherein the associated stationary contacts and the movable contacts are easily aligned.

A further object of the present invention is the provision of a certain two-piece frame construction supporting the stationary and movable elements of an electric switch construction wherein maximum visibility of the air gap is provided and whereby the position of the movable elements may be readily ascertained.

Other objects and features of the present invention will be apparent upon a perusal if the following specification and drawings, of which:

Figure 1 is a front elevational view of an electric switch construction according to the present invention;

Figure 2 is a side elevational view of the structure shown in Figure l; t

Figure 3 is a cross sectional view of the structure shown in Figure 2 and taken along the line 33 of Figure 2;

Figure 4 is a cross sectional view of the structure shown in Figure 1 and taken along the line 4-4 of Figure 1;

Figure 5 is a cross sectional view of the structure shown in Figure l and taken along the line 5-5 of Figure 1;

Figure 6 is a cross sectional view of the structure shown in Figure 5 with the switch in the open position;

Figure 7 is a cross sectional view of the structure shown in Figure 3 and taken along the line 7-7 of Figure 3;

Figure 8 is a front elevational view of another embodiment of the present invention;

Figure 9 is a side elevational view of the structure shown in Figure 8;

Figure 10 is a bottom view of the structure shown in Figure 8; and

Figure 11 is a cross sectional view of the structure shown in Figure 8 and taken along the line 1111 of Figure 8.

The present embodiments are the preferred embodiments but it is to be understood that changes can be made in the present embodiments by one skilled in the 3 art without departing from the spirit and scope of this invention.

Each of the two embodiments of the present invention generally comprises-three components, namely, a one-piece unitary U-shaped supporting frame having a pair of spaced apart side walls interconnected by a bottom wall, a shelf structure movably cooperating with said U-shaped supporting frame, and an upper supporting element mounted across said side walls. These various elements carrythe remainder of the switch construction and by a particular method of construction form electric switch constructions embodying all of the previously noted objects and features. The bottom wall of the lower U-shaped supporting frame carries one or more'insulated contact means, the upper supporting frame also carries one or more insulated contact means vertically aligned with the insulated contact means carried by the lower supporting frame, and the movable shelf carries insulated contact means therein for sliding reciprocating contact between the noted insulated 'contact means in the upper and lower supporting frames.

For a detailed description of the first embodiment of the present invention, reference is made to Figures 1 through 7. The lower supporting frame is generally U-shaped having a bottom wall 16 and twovertical side Walls 17 and 18. The vertical side walls 17 and 18 and the bottom wall 16 are generally channel-shaped in cross section. A vertical strap 19 is secured to the rear edge of side wall 17 and a vertical strap 20 is secured to the rear edge of side wall 18. Vertical strap 19 is provided with mounting holes 21 and 23 therethrough, and vertical strap 20 is provided with mounting holes 22 and 24 therethrough for mounting of the switch construction to. any suitable wall or other structure (not shown).

The cover or upper supporting frame 25 is also channel-shaped in cross section with closed ends to form an inverted trough. The rear marginal edge of the upper supporting frame 25 is provided with two holes therethrough, and screws 26, only one of which is shown in Figures 4 and 6, secure the frame 25 to the

vertical straps

19 and 20. The front marginal edge of the upper supporting frame 25 is also provided with two holes therethrough, and

screws

27 and 28 are threaded into apair of'vertical straps 29 secured to the front marginal edges of the side walls 17 and 18 to securely mount the front of the cover 35 to the lower supporting frame 15.

The shelf 30 is a generally longitudinal member having a channel-shaped cross section, as can be seen in Figure 4, and having a width substantially less than the width of the side walls 17 and 18. Each end of the shelf structure 30 is formed to have a pair of spaced and apertured cars 31 and 32, substantially at the center thereof. The apertures of the cars 31 and 32 lie along a common horizontal .axis and pins 33 are mounted therethrough. The extending end portions of the pins 33 have an enlarged diameter and are so formed to cooperate with a pair of guide channels 34. The guide channels 34 are vertically positioned and secured to the inner surfaces of the side walls 17 and 18. Thus it can readilybe seen that as the pins 33 cooperate with the guide channel 34, the shelf 30 is slidable in upward and downward directions between the bottom wall 16 of the lower supporting frame 15 and the upper supporting frame 25. To provide means operable externally of the switch construction to raise or lower the shelf 30, a pair of links 35 are provided. One end of the links 35 is pivotally mounted about pins 33 between the spaced cars 31 and 32 of the shelf 30. The lower or other end of each link 35 is pivotally mounted to one end of a lever 36 by means of a pin 37. The other or lower ends of the levers 36 are secured as by welding to shaft 38. The shaft 38 is journaled within bushings 39 which are secured to the side Walls 17 and 18 of the lowersupporting frame 15. Each end of the shaft 38 extends outwardly from the side walls 17 and 18 and is provided with a key way 40 by which an operating handle (not shown) may be connected to the shaft 38 for a reciprocating linkage control or for a shaft extension when required. The upper end of each lever 36 is provided with an extension 41 which serves as a limit stop in the raising of the shelf 30. The upper end of each lever 36 is further provided with an extension 42 which serves as a limit stop in the downward movement of the shelf 30. It can thus be seen that if the shaft 38 is rotated in a counterclockwise direction as viewed in Figure 4, the shelf 30 will be moved from the upper position shown in solid lines to the lower position shown in dotted lines, and an opposite rotation of the shaft 38 will again raise the shelf 30 to the upper position shown in Figure 4.

Turning next to the remaining elements of the switch construction which are mounted to the bottom Wall 16 of the lower supporting frame 15, the upper supporting frameor cover 25, and the shelf 30, three independent switch contact means are shown. However, this number is shown for purposes of illustration only, and it may easily be seen that from the previously described constructions, the lower supporting frame 15, the upper supporting frame 25, and the shelf 30 may be lengthened or shortened to accommodate any number of independent switch contact means. Each of the three independent switch contact means is identical in construction and, therefore, only one need be described in detail herein.

The bottom wall 16 of the lower supporting frame 15 is provided with a relatively large opening, and a flanged collar 43 is secured to the marginal edges of this opening. The collar 43 may be secured by welding, beading of the adjacent marginal edges of the collar 43 and the opening, or any other means well known in the art. A cup-shaped insulator 44, preferably made from a wet process porcelain, is positioned to extend through the collar 43 and is secured therein by a compound 45. The compound operates to bond the insulator 44 to the collar 43 through the compound. The compound 45 is a material which is easily used in a fluid or semisolid state, which later turns to a solid usually through its own self-hardening properties, and which bonds itself or securely interlocks with any surface variations in the adjacent material and, therefore, the compound 45 may be a compound such as babbitt, Portland cement, litharge or any other plastic material having the noted properties. These compounds in the set or solid state will effectively and accurately position andmaintain the elements to which they are bonded. The process of mounting the insulator 44 through the collar 43 may be easily accomplished when the upper supporting frame 25 and the shelf 30 are removed from the lower supporting frame 15. The bottom of the insulator 44 is formed to have an opening therethrough and a liner 46 is formed thercin'having a horizontal hexagonal recess 47. The liner 46 may. be formed of a material such as babbitt or any suitable ones of thecompounds previously noted. A rod-shaped conductor 48 of a cylindrical cross section and with a hexagonal flange 49 is formed of a material having a high electrical conductivity. The lower end ofthe conductor 48 isthreaded and projected through the liner 46 with the hexagonal flange 49 cooperating with the hexagonal recess 47; A washer 50 and a nut 51 are then mounted about the depending lower end of the conductor 48 within the insulator 44. V

The switch contact means of the upper supporting frame 25 is formed in a manner similar to that described for the lower supporting frame 15. The upper support ing frame 25 is provided with a relatively large opening therethrough and a collar 52 similar to collar 43 is secured about the edges thereof. An inverted cup-shaped insulator 53 is secured through the collar 52 and is bonded thereto through the compound 54 which is similar to compound 45. The insulator 53 may be easily bonded to the collar 52 when the upper supporting frame 25. is removed fromthe lower supporting frame 15. Similarly, the insulator 53 is provided with an opening therethrough in which a liner 55 having a hexagonal recess 56 is mounted. The liner 55 is formed of a suitable compound similar to liner 46. A rod-shaped conductor 57, similar to conductor 48, is also provided. However, conductor 57 is relatively shorter than conductor 48, as can easily be seen in the drawings. Conductor 57 is also formed to have a hexagonal flange 58 similar to flange 49, and this flange 58 cooperates with the'hexagonal recess 56. The upper end of the conductor 57 is threaded and extends upwardly from the insulator 53. A washer 59 and a nut 60 are then mounted about this projecting upper end to secure the conductor 57 within the insulator 53. When the various bonding compounds 45 and 54 and the

liners

46 and 55 are properly formed of correct amounts and in correct thicknesses, the conductor 57 is longitudinally axially aligned with the conductor 48. Each of the

conductors

48 and 57, respectively, are provided with

additional nuts

61 and 62 for the terminal connection of suitable cabling (not shown) thereto. The opposing ends of the

conductors

48 and 57 are then seen to represent related stationary switch contacts.

@The movable contact member of the switch contact means comprises a sleeve 63 which is formed of a material having a high electrical conductivity. To properly support and align the sleeve 63 a tubular bushing type insulator 64 is provided. The insulator 64 is positioned through an opening in the shelf 30 and is bonded thereto by a bonding compound 65 similar to bonding compound 45 previously described. The insulator 64 is aligned along its longitudinal axis so that when the shelf 30 is raised or lowered respectively, the upper and lower ends of the insulator 64 are respectively projected within the

insulators

53 and 44. The internal central section of the'insulator 64 is formed to have a reduced diameter and is provided with a liner 66 which is formed of a material similar to compound 46 previously described. The liner 66 is formed with an annular seat 67 and 68 at each end thereof. The seats 67 and 68 may be accurately and easily formed, through the use of the noted materials to provide an annular seat which is normal to the longitudinal axis of the insulator 64. The tubular conductor or sleeve 63 is positioned through the liner 66 and has a diameter slightly smaller than the inner diameter of the liner 66. Retaining rings 69 and 70 are then secured to the conductor 63 and are positioned respectively to cooperate with the opposed seats 67 and 68. This cons-tru-ction permits a minimum amount of endwise movement of the conductor 63 relative to the insulator 64 and also permit a limited amount of horizontal shifting of the longitudinal axis of the conductor 63. This construction provides a certain amount of self-alignment of the conductor 63 relative to the

stationary contacts

48 and 57. In order for conductor 63 to make a good electrical contact with the

stationary conductors

48 and 57, the upper end of the conductor 63 is split into a plurality of longitudinal segments 71 and the lower portion of the conductor 63 is split into a plurality of longitudinal segments 72. These segments render the ends of the conductor 63 flexible. Garter type springs 73 mounted about the ends of the segments 71 and 72 bias the segments toward the longitudinal axis of the conductor 63 and provide a good circular pressure contact of the conductor 6-3 with the

conductors

48 and 57. It should be noted that, as can be seen in the drawings, the conductor 63 makes contact in all positions of the switch with the conductor 48 but only makescontact with the conductor 57 when the shelf 30 is in the upper position or closed position of the switch. It should further be noted that the described construction of the movable cont-act member on the shelf may be easily accomplished when the upper supporting frame 25 is removed and the shelf 30 is removed from the lower supporting frame 15.

Turning next to a description of the operation of the described embodiment, reference is again made to Figures 1 through 7. The switch of this embodiment is shown in the up or closed position in Figures 1, 3 and 5 and in the solid lines in Figure 4. The switch is shown in the down or open position in Figure 6 and in the dotted lines in Figure 4. Referring particularly to Figures 3 and 4, it maybe seen that the lever-s 36, the links 3-5 and their pivotal connections may be likened to 'a toggle action arrangement, and as shown in the solid lines in Figure 4, the pin 37 is in an over-toggle position with the limit stop 41 against the rear edge of the side wall 18. If the shaft 38 is then turned in a counterclockwise direction as viewed in Figure 4 toward the open position,

the first portion ofthe opening operation will cause pin 37 to approach the toggle position. The shelf 30 will be forced upwards with a gradually increasing mechanical advantage thereby providing a great force to break any contact seal that may have occurred between the various switch contact means with but a relatively small moment applied to the shaft 38. Continued rotation. of the shaft 38 in the same direction will cause the pin 37 to move through the toggle position, and to pull the shelf 30 downwardly as the pins 33 slide within the channel guides 34 until the opening operation is completed, with the shelf 30 at the lowermost position. The shelf 30 will then have assumed the position shown in the dotted lines in Figure 4 with the limit stop 42 against the bottom wall 16 of the lower supporting frame 15. At this position the described switch contact means will have the relative positions shown in Figure 6, and as can be seen therein the air gap between the conductor 57 and the contact sleeve 63 may be, easily viewed from the front of the switch. The switch is moved to the closed position by a reverse operation of that described above to again bring the switch to the 'closed position noted in the drawings.

Turning next to a detailed description of the second embodiment of the present invention, reference is made to Figures 8 through 11. The switch contact means of this embodiment are substantially similar in function, structure, operation and result to the switch contact means previously described, and therefore, need not be described in detail herein. The essential difference between this embodiment and that previously described is the construction of the lower supporting frame, the upper supporting frame and the movable shelf. The lower supporting frame 75 is generally U-shaped having a bottom Wall 76 and two

vertical side walls

77 and 78. The

side Walls

77 and 7 8 in this embodiment are not fiat rectangular members but are bar-shaped as can be seen in the cross section in Figure l1 and are brazed to bottom wall 76. The shaft 79 which is similar to shaft 38 is journaled through

bearings

80 and 81 which are formed on the bottom wall 76 and extend upwardly therefrom. The upper end-s of the

side walls

77 and 78 are each formed to have a reduced threaded portion at the upper end thereof. The bottom wall 76'of the lower supporting frame 75 is provided with a pair of lugs 82 at the rear marginal edge thereof for fastening of the switch assembly to any suitable structure. wall 83 is channel-shaped in cross section with closed ends to form an inverted trough. The rear marginal edge of the upper supporting frame 83 is provided witha plurality of lugs 84 for mounting the switch assembly to any suitable structure. The upper supporting frame 93 is further provided with a pair of openings therethrough at each end thereof. These openings are positioned so that the upper supporting frame 83 may be mounted upon the lower supporting frame 75 with the upper ends of the

side walls

77 and 78 projecting through these openings.

The upper supporting it Nuts 85 then secure thezupper supporting frame 83 to the 7'5 may be provided with additional support means such as members 86 and 87.if further strength is necessary.

Members

86 and 87 are then; formed similarly to side walls 77 and 78'and cooperate in a similar manner with the upper supporting frame83;

The, shelf 88'of the present embodiment is formed sub 'stantially as shelf 30except that each end of the shelf 88 is formed to have an opening 89 therethrough. Pins 90 are secured within one wall of these openings 89 and these pins provide the pivotal supporting means for links 91. A further difference is the formation of a pair of spaced apart cars 92 at each end of the shelf 88, as can easily be seen in Figure 11. Each pair of ears 92' extends outwardly in a horizontal direction and are spaced apart a distance substantially equal to the outer diameter ofthe side walls 77"and 78; The shelf 88 is of such a length that the ears 92 cooperate with the side walls 77 so that the side Walls, 77 and 78 serve as guides for the vertical movement of the shelf 88. The links 91 are pivotally connected to levers 93 which in turn are keyed or securedto the. shaft 79; With this arrangement, the bottomwall 76 serves as a limit stop for the counterclockwise rotation of the levers 93, as viewed in Figure 9, to the open position of the switch. The levers 93 are further provided with limit stops 94, and these limit stops cooperate with limit stops 95 which are formed on the bottom wall 76 of the lower supporting frame 75, as can be seen in Figure 9; The switch assembly of the second embodiment is substantially similar in operation to the operation of the first embodiment It' is contemplated in the present invention that if desirable, the pins 90'may be removed from the openings 89 and mounted instead to a member (not shown) which is secured between the ears 92 outwardly from the

side walls

77 and 78. This causes a relocation of the link-s 91 and the levers 9 3 to positions outwardly of the

side walls

77 and 7 8.

Having described the invention, what is considered new and desired to be protected by Letters Patent is:

1. In an electric switch of the type having a pair of cup-shaped insulators each carrying a contact stud therein and havinga bushing insulator carrying a sleeve contact, means for mounting said pair of cup-shaped insulators in axial alignment with each other and with said bushing insulator for cooperation between said sleeve contact and said contact studs comprising: a lower supporting frame, an upper supporting frame, and a movable shelf, said lower supporting frame having a unitary bottom wall'and a pair of spaced apart side walls and being open at the top thereof, said upper supporting frame separably fastened to said side walls, means removably mounting said movable shelf between said side walls for upward and downward movement of said shelf,

said'last-mentioned means comprising a pair of cars formed to project from each end of said shelf, the ears of each pair of said ears being spaced apart a distance substantially equal to the width of said side walls and positioned one on each side of said side walls, each side of said side walls'being formed to guide said ears whereby said shelf is movable upwardly and downwardly between said side walls and is removable as a unit from the top of said lower supporting frame, an opening provided throughreach of said bottom wall, said upper supporting frame and said movable, shelf, bonding means securing one insulator of said pair of cup-shaped insulators to said bottom wallthrough said opening therein, second bonding means securing the other insulator of said pair of cup-shaped insulators to said upper supporting frame through said opening therein, third bonding means securing said bushing insulator to said shelf through'said opening therein and in axial alignment with said pair of cup-shaped insulatorsandpositioned whereby saidsleeve-contact isin constant engagement with the 8 contact stud of-said oneinsulator and movable to-make and 'break contact with the contact stud carried by said other insulator."

2, In anelectric switch as claimed in claim 1, wherein each of said bonding means comprises a compound hav ing the properties of a substantially fluid state when placed-between said pair of insulators, said bushing insu-- lator, and said bottom wall, said upper supporting frameand said shelf, and a substantially solid state thereafter to effectively permanently bond said cup-shaped insu-. lators and said bushinginsulator to said lower supporting: frame, said upper supporting frame and said shelf, 'respec tively.

3. Inan=electric switch of the-type having a frame comprisinga bottomwall and an upper Wall andhaving a shelf movably mounted therebetween for upward and" downward movement, and having one cup-shaped insulator mounted through said bottom wall, another cup.-. shaped insulator mounted through said upper wall,.and a bushing insulator mounted through said shelf, a pair of contact studs for said cup-shaped insulators and formed to have annular flanges thereon, a sleeve contact for said bushing insulator, means for positioning said: pair of contact studs in respective ones of said cup,v shaped insulators and said sleeve contact in said bushing insulator in a spaced axial alignment with each other. and for cooperation between said sleeve contact and said; contact studs comprising-molded liners formed in each of said pair of cup-shaped insulators and said bushing insulator, said molded liners for said cup-shaped ll'lSl-lrz lators comprising a cylindrical portion and an annular seat portion molded in said cup-shaped insulators so that the cylindrical portions of each liner are coaxial and so that the annular seat portions are normal thereto so that said contact studs are mountable in said cylindrical portions with said annular flanges abuttingsaid annular seats to position said contact studs in a prede-i termined spaced apart relationship to each other along the same axis, said molded liner for said sleeve contact comprising a cylindrical portion and annular seat portions molded in said bushing insulator so that said annular seat portions are formed at each end of said cylindrical portion and normal thereto and so that said. cylindrical portion iscoaxial with said cylindrical portions of said molded liners for said cup-shaped insulators whereby said sleeve contact is mountable in said cylindrical portion, said cylindrical portion of said molded liner for said sleeve contact having an internal diameter of a predetermined amount larger than the outer diameter of said sleeve contact to permit a certain amount of lateral movement of the longitudinal axis of said sleeve contact for self-alignment of said sleeve contact relative to said contact studs responsive to any lateral' shifting of said shelf relative to said bottom and upper walls, and a pair of retaining rings secured about said sleeve contact and positioned at opposite ends of said molded liner for said sleeve contact to engage said annular seat portions thereof to maintain said sleeve contact along an axis parallel to the axis of said contact studs, said pair of retaining rings each having an outer diameter greater than the inner diameter of said molded linerfor said sleeve contact whereby said pair of retaining rings further prevent any axial movement of said sleeve contact relative to said bushing insulator.

4. In an electric switch, a lower supporting frame having a unitary bottom wall and a pair of spaced apart side walls, a movable shelf, means removably mounting said movable shelf between said side walls for upward and downward movement of said shelf, an upper sup porting frame, means removably fastening said upper supporting frame to said side walls, one cup-shaped insulator mounted through said bottom wall, another cup; shaped insulator mounted through said upper supporting frame, a bushing insulator-mounted through said shelf, a pair of contact studs for said cup-shaped "insulators and formed to have annular flanges thereon, a sleeve contact for said bushing insulator, means for positioning said pair of contact studs in respective ones of said cupshaped insulators and said sleeve contact in said bushing insulator in a spaced axial alignment with each other and for cooperation between said sleeve contact and said contact studs comprising molded liners formed in each of said pair of cup-shaped insulators and said bushing insulator, said molded liners for said cup-shaped insulators comprising a cylindrical portion and an annular seat portion molded in said cup-shaped insulators so that the cylindrical portions of each liner are coaxial and so that the annular seat portions are normal thereto so that said contact studs are mountable in said cylindrical portions with said annular flanges abutting said annular seats to position said contact studs in a predetermined spaced apart relationship to each other along the same axis, said liner for said sleeve contact molded to position said sleeve contact in said bushing insulator in axial alignment with said contact studs for cooperation therewith.

5. In an electric switch, a lower supporting frame having a unitary bottom wall and a pair of spaced apart side walls, a movable shelf, means removably mounting said movable shelf between said side walls for upward and downward movement of said shelf, an upper supporting frame, means removably fastening said upper supporting frame to said side walls,an opening provided through each of said bottom wall, said upper supporting frame and said movable shelf, a pair of cup-shaped insulators positioned through respective ones of said openings in said bottom wall and said upper supporting frame, a bushing insulator positioned through said opening in said shelf, a bonding compound securing the cup-shaped insulator positioned through said bottom wall to said bottom wall, a second bonding compound securing the cup-shaped insulator positioned through the opening in said upper supporting frame to said upper supporting frame, a third bonding compound securing said bushing insulator to said shelf for telescopic movement of said bushing insulator within said cup-shaped insulators, a pair of contact studs for said cup-shaped insulators and formed to have annular flanges thereon, a sleeve contact for said bushing insulator, means for positioning said pair of contact studs in respective ones of said cupshaped insulators and said sleeve contact in said bushing insulator in a spaced axial alignment with each other and for cooperation between said sleeve contact and said contact studs comprising molded liners formed in each of said pair of cup-shaped insulators and said bushing insulator, said molded liners for said cup-shaped insulators comprising a cylindrical portion and an annular seat portion molded in said cup-shaped insulators so that the cylindrical portions of each liner are coaxial and so that the annular seat portions are normal thereto so that said contact studs are mountable in said cylindrical portions with said annular flanges abutting said annular seats to position said contact studs in a predetermined spaced apart relationship to each other along the same axis, said liner for said bushing insulator being molded to position said sleeve contact in axial alignment with said contact studs for cooperation therewith.

6. In an electric switch having a stationary frame, a pair of aligned upper and lower rod-shaped contact studs supported in said frame in an insulated relation thereto and to each other and having a shelf guided for up and down movement within said frame, a bushing insulator secured to said shelf in alignment with said pair of upper and lower contact studs, a sleeve contact having a pair of retaining rings mounted thereabout normal to the longitudinal axis thereof and in a certain spaced apart relationship, a molded liner for positioning said sleeve contact in said bushing type insulator in constant engagement with the lower contact stud and movable into and 10 out of engagement with the upper contact stud, said molded liner comprising a cylindrical portion and annular seat portions molded in said bushing insulator so that said annular seat portions are formed at each end of said cylindrical portion a distance substantially equal to the distance between said retaining rings and normal thereto and so that said cylindrical portion is coaxial with said contact studs whereby said sleeve contact is mountable in said cylindrical portion with said retaining rings engaging said annular seat portions, said cylindrical portion having an internal diameter a predetermined amount larger than the outer diameter of said sleeve contact to permit a certain amount of lateral movement of the longitudinal axis of said sleeve contact while maintaining the longitudinal axis of said sleeve contact parallel to the axis through said upper and lower contact studs so that said sleeve contact is self-aligning relative to said contact studs responsive to any lateral shifting of said shelf relative to said frame, and actuating means for said shelf for moving said sleeve contact into and out I of engagement with said upper contact stud.

7. In an electric switch of the type having a frame, a pair of upper and lower rod-shaped contact studs supported in said frame in insulated relation thereto and to each other, and having a shelf guided for up and down movement within said frame with means for moving said shelf in said upward and downward movement, a bushing insulator secured to said shelf in axial alignment with said pair of upper and lower contact studs, a liner formed of a bondable compound bonded within said bushing insulator, said liner formed to have a cylindrical portion and annular seat portions formed at each end of said cylindrical portion and normal thereto, a sleeve contact having an outer diameter a certain amount less than the inner diameter of said cylindrical portion of said liner, said sleeve contact positioned within said cylindrical portion of said liner in axial alignment with said upper and lower contact studs and in constant engagement with said lower contact stud and movable into and out of engagement with said upper contact stud, a pair of retaining rings mounted about said sleeve contact adjacent said annular seat portions at each end of said liner and having an outer diameter greater than the inner diameter of said cylindrical portion of said liner, whereby said sleeve contact is laterally movable a certain amount for self-alignment axially relative to said upper and lower contact studs and whereby said sleeve contact is retained against any axial movement relative to said liner.

8. In an electric switch of the type having a pair of cup-shaped insulators each carrying a contact stud therein and having a bushing insulator carrying a sleeve contact, means for mounting said pair of cup-shaped insu' lators in axial alignment with each other and with said bushing insulator for cooperation between said sleeve contact and said contact studs comprising: a lower supporting frame, an upper supporting frame, and a movable shelf, said lower supporting frame having a unitary bottom wall and a pair of spaced apart side walls and being open at the top thereof, a pair of cars carried at each end of said movable shelf and engaging said side walls so that said side walls guide said shelf for upward and downward movement of said shelf between said side walls, said side walls formed at the top thereof so that said ears are disengageable therefrom by an upward movement of said shelf therefrom whereby said shelf is removable as a unit from the top of said lower supporting frame, said side walls further formed to cooperate with said upper supporting frame to support said upper supporting frame at a predetermined position from said bottom Wall, means separably fastening said upper supporting frame to said side walls, one insulator of said pair of cup-shaped insulators mounted to said bottom wall, the other insulator of said pair of cup-shaped insulators mounted to said upper supporting frame in axial 1 i alignment with said one insulator, said bushing insulator mounted to said shelf in axialalignment with said pair of cup-shaped insulators and positioned whereby said sleeve contact is in constant engagement with the contact stud of said one insulator and movable to make and break contact with the contact stud carried-by said other insulator;

9. Inan electric switch of the type having a pair of cup shaped insulators each carrying a contact stud therein and having a bushing insulator carrying a sleeve contact, means for mounting said pair of cup-shaped insulator's in axial alignment with each other and with said bushing insulator for cooperation between said sleeve contact and said contact studs comprising: a lower supporting frame, an upper supporting frame, and a movable shelf, said lower supporting frame having a unitary bottom wall and a pair of spaced apart side walls and being open at the top thereof, said side walls being formed as upwardly extending rods substantially normal to said bottom wall at each end of said bottom wall, a pair of ears integrally formed on said movable shelf at each end thereof, said ears being spaced apart a distance substantially equal to the diameter of said side walls and extending outwardly from said movable shelf a distance substantially equal to the diameter of said side walls, said movable shelf positioned between said side walls with each of said pair of ears including one of said side walls therebetween in a sliding relationship for upward and-downward movement of said shelf between said sidewalls; said-"side walls. formed at the upper ends thereof so that'sa'id'ears are di'sengageable then-iron: by an upward movement of said-shelf therefrom whereby said shelf is removable as a unit from the top of said lower supporting frame, said side walls further formed to cooperate with said upper supporting frame to support said upper supporting frame at a predetermined parallel position-to saidbottorrr wall, means separably fastening said upper supporting frame to said side walls, one insulator of said pair of cup-shaped insulators mounted to said bottom wall, the other insulator of said pair of cupshaped insulators mounted to said upper supporting frame in axial alignment with said one insulator, said bushing insulator mounted to said shelf in axial alignment with said pair of cup-shaped insulators and positioned whereby said sleeve contact is in constant engagement with the contact stud of said one insulator and movable to make and break a contact with the contact stud carried by said other insulator.

References, Cited in the file of this patent UNITED STATES PATENTS 2,203,863 Farrell June 11, 1940 2,229,006 Rudd Jan. 14, 1941 2,229,504 Hoye Jan; 21, 1941