US1240314A - Oil-switch. - Google Patents

Description

H. W. CHENEY.

OIL SWITCH.

APPLICATION men SEPT, 16, 1910.

Patented Sept. 18, 1917.

4 SHEETSSHEET l.

H. W. CHENEY.

OIL SWITCH.

APPLICATION FILED SEPT. I6, 1910.

. 1,240,314, PatentedSept. 18,1917.

4 SHEETS-SHEET 2.

H. W. CHENEY.

OIL SWITCH.

APPLICATION FILED SEPT. 16. 1910.

1,240,314. Patented Sept. 18,1917.

4 SHEETS-SHEET 3.

/s M ii: /3 W f nnnnnnnnnnnnnnnnnnnnnnnflq Y W'Meee Ema/More H. W. CHENEY.

OIL SWITCH.

APPLICATION FILED SEPT. 16. 1910.

1,240,314. PatentedSept. 18,1917.

4 SHEETS-SHEET 4- Ia'IIIIII IIIIIAi WAX/wow a/vvwmX/o/u 5 47 MMW (2 UNITED STATES PATENT oEEioE.

HERBERT W. CHENEY, OF MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO ALLI-S-CHALMERS MANUFACTURING COMPANY, A CORPORATION OF DELAWARE.

OIL-SWITCH.

Patented se t. 18, 1917.

Original application filed March 27,1909, Serial No. 486,171. Divided and this application filed September 16, 1910. Serial No. 582,301.

To all whom it may concern:

" Be it known that I, HERBERT WV. CHENEY, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of-Visconsin, have invented certain new and useful Improvements in Oil- Switches, of which the following is a full, clear, and exact specification.

My invention relates to oil switches, particularly to those of large capacity. This present application is a division of my copending application Serial No. 486,171, filed March 27, 1909.

One of the objects of the invention is the provision of aswitch which can be safely employed in circuits of exceedingly high voltages and. large amperages without any danger of the arcs causing injury to the operator or to any of the apparatus.

A further object is to provide for a switch of high capacity switch mechanism which is strong, durable and effective in operation, which is well insulated from the oil tank and other surrounding parts and which is so constructed that access may be readily had to all parts.

Other objects will appear hereinafter.

My invention consists in certain novel details of construction and combination and arrangements of parts which will be described in the specification and set forth in the appended claims.

I have in the present case shown my invention as applied to three pole "switches such as are employed in three phase circuits, and have shown the contact mechanism of each pole inclosed within a separate oil compartment and receptacle. It is understood, however, that my invention is not limited in its scope to a switch of any particular number of poles and in many of its aspects is not limited to' a switch having the mechanism, of its poles arranged, con-' structed or inclosed as here shown.

For a better understanding of my invention, reference is had to the accompanying sheets of drawings, in which Figure 1 is a side elevationof a switch constructed in accordance with my invention, parts being broken away and other parts being in section;

Fig. 2 is a sectional view, taken through one of the tanks and poles of the switch substantially on the line 2-2 of Fig. 1, the switch being here shown in its open position;

Fig. 3 is a sectional view, the section being taken between two of the poles and between the adjacent tanks or compartments,

substantially along the line 33 of Fig. 1, the different parts of the operating mechanism being shown in the position which they occupy when the switch is closed;

Fig. l is an enlarged elevation of part of the stationary and movable contact members employed in each pole of the switch, the contacts being separated or out of en- 'ga gement Fig. 5 is a similar view showing the contacts in engagement and showing the relative positions of the parts when the switch is closed; I

Fig. 6 is a top plan View of one of the lower or stationary contact members;

Fig. 7 is a detail of the buffer employed in number, said tanks being preferably formed of sheet metal and each being provided with a cover 12 which is preferably divided along the longitudinal center or into two halves each of which is separately secured to the tank preferably by screws or bolts 12 which pass through horizontal flanges 12 on the cover and through horizontal flanges of angles 12 secured to the tank and extending about the upper edge of the same. Supported by the cover of each tank between the two parts of the same and near the ends thereof are insulators or insulating bushings 13 having vertical passageways which receive respectively conductors 14 which are surrounded by insulating sleeves 14 and each cover also supports between the parts or halves thereof and between the insulators 13, a pair of bushings v versely across the may 12? extending 3 19 to lugs 21 on the sides 0 the frame.

60 inner casing 5 anism to be explained later.

The different tanks 12 may be adjusted or held in fixed positions relative to the frame and to one another, and the passageways in the different bushings may be 10 brought in absolute vertical alinement by several tank adjusting and holding devices including set screws 17 which extend through vertical flanges 10 of the frame, or through short angles 10 extending transframe between the tanks. These set screws 17. engage the lower parts of the tanks on all four sides, and provide means whereby the tanks may be bodily shifted, or-whereb'y the lower portions only be shifted while the upper parts are held stationary. tanksare mutually braced and spaced apart by means of transverse threaded bolts or rods 18 passing through the vertical flanges downward from the covers, said bolts being provided at their threaded ends with nuts which ermit the upper ends of the tanks to be ad usted relative to one another. The tanks are also held down to the frame, by pairs of tie rods 19 which are attached by means of bolts or screws 20 to opposite sides of the cover 12 of at least the middle tank 12, and are adjustably connected at their lower ends b means ofnuts means of these various holding and adjusti ing devices the tanks can be held in proper osition relative to one another and to the rame so as to permit the different parts of the operating mechanism to work freely.

In order that there may be between the contact mechanism or other live parts of the switch and the tank, a better insulation than that which is obtained by the oil alone, I provide within each tank, and a short'distance from the walls thereof, a casing or peeeptacle 26 which is made of insulating material such as wood and is provided with an open top, and between the bottom and sides of this receptacle and the bottom and sides of the tank, I- provide a number of separated or spaced layers 27 of insulating material such as fuller board, insulating supporting members 28 being provided at intervals between these different layers, so as to hold them predetermined distances apart. Between the top of the inner casing 26 and the top of the tank is a separating collar26 of wood or other insulating material. This 26 and the insulatingwalls or layers 27 are not oil tight, but the oil is permitted to enter between the difl'erent layers sothat between the contacts and the metal walls of the tank there are alternate layers of oil and of solid insulating material. This The upper ends of the' arrangement provides a better insulation than the oil alone would "provide, for the reason that when the oil is relied upon, the oil between a certain portion of the -tank and a live part of the switch may be blown away or blown aside by the are which will then remain established, causing immediate burning of the parts and destruction of the switch. Suitably supported by the bottom of the inner box or receptacle 1s a frame 29 of insulating material such as wood, and secured to this frame are three insulators 30, 31, and 32, which, as will be explained, support part of the contact mechanism. Between these insulators are arranged dividing partitions 33 and 34; preferably formed of separate spaced layers of insulating material, such as are provided along the bottom and sides of the tank- The contact mechanism of each pole of,

the switch, which will now be explained, includes four yieldingly mounted main stationary contacts which are adapted to be bridged in a manner to be explained so as to provide a quadruple break or four point break switch, the movable contacts being carried by vertically movable plungers and being given an 'upward movement away from the stationary contacts, when the switch is opened, so as to draw the arcs upwardly. Secured to the upper ends of the insulators 30 and 32 in each tank are metal caps 35 to the upper surfaces of which are secured, preferably by screws 37 (see Figs. 5 and 6) two similar cast metal contact holdem or supporting castings 38 formed of good conducting material, such as brass. Each of these holders 38 is provided with a horizontal base 89 which engages the corresponding cap 35 and which extends laterally beyond the corresponding insulator and is mechanically and electrically connected to one of the terminal rods 14, which, as stated before, extend down into the tank through the insulators 13, the lower ends of the terminal rods being screwed into threaded sockets in bosses 39 of, the holders. Each of these holders is provided also with an arm or bracket 40 which extends upwardly from the base and is provided with a Vertical socket or guide 40 (see Fig. 5) which receives one of the main contacts 41 having at its lower end a shoulder 41, which limits the upward movement of the contact and which is yieldingly supported and is pressed 120 upwardly by means of a rather heavy coil spring 43 located between the shoulder 41 of the contact and the base of the holder. This contact 41 is connected to the base of the corresponding holder by means of a 125 ing located intermediate the head of the 130 screw and the end of the shunt. The arm or bracket 40 of the holder also supports a pivoted U-shaped arm or member 47, which Is pivoted to the upper end of the bracket by means of a pin 48 passing through the bracket and through the free ends of the U- shaped member 47, and has at its forward end .an auxiliary contact or arcing tip 49. The forward end of the pivoted member 47 and the contact 49 are yieldingly held upward so as to extend above the end of the contact 41, as shown clearly in the drawings, by means of a coil spring 50, one end of which'engages a transverse pin 51 mounted in the bracket 40 a short distance above the base and the other end of which engages a pin 52- extending transversely between the ends of the pivoted member 47.

The insulator 31, which is located midway between the insulators 30 and 32, has secured to its upper end a cap 53 on the top of which is secured acasting or holder 54 which has two sets of main and auxiliary contact members such as are carried by each of the holders 38, the two sets being located near the opposite ends of the holder and be ing separated by a vertical barrier 55 which extends downward from the top of the wooden inner receptacle or casing 26 to the base of the casting 54. As will be apparent from Fig. 2 of the drawings, this contact holder or casting 54 has two main contacts 56, similar in all respects to the contacts 41 and yieldingly supported as the latter con-.

tacts are supported, and is provided also with two pivoted or swinging arms 57 which carry respectively auxiliary contacts or arcing tips 58 which are, as in the first instance, yieldingly held upward above the contacts 56, by springs. Thus it will be seen that each holder or contact supporting casting 38 and the corresponding main contact 41.constitute a single-break stationary contact member, while the contact supporting casting 54 and the two main contacts 56 carried thereby constitute a stationary bridging contact member having two main breaking points.

The movable contact members for each 'pole are carried by the plungers 16 which, as stated before, extend down through the bushings 15 which are mounted in the cover 12 intermediate the insulators 13. Clamped to the lower ends of the plungers 16 are two U-shaped bridging conductors 60 and 61 each of which is secured to the corresponding plunger by a-cla-mp 62. These conductors,

which are formed of good conducting mate- -r'al, have. downwardly projecting free end ortions, and are so arranged that the free ends of one of the conductors are-vertically above the contact 41 of one of the holders 38, and one of the contacts 56 of the middle holder, and the free ends of the other con-' ductor are vertically above the contact 41 of the other contact holder 38. and the other contact 56 of the middle holder.- Secured to the lower ends of each of these conductors, are main movable contacts 63 and 64 which have threaded sockets and. are screwed onto threaded lower ends of the conductors, as is shown clearly in Fig. 4. The lower faces of these contacts are adapted to engage the upper faces of the contacts 41 and 56 when the switch is closed. The bridging conductors 60 and 61 are also provided with auxiliary or arcingcontacts 65 and 66 which are clamped between the upper ends of the main movable contacts 63 and 64 and lock nuts 67 and 68,.the lower ends of the auxiliary contacts 65 and 66 extending downward be- .low the lower ends of the main contacts 63 sion of the springs 43, so that the latter will cause the main contacts to be held together under a considerable degree of pressure. The contacts 41 and 56 have, as shown clearly in Figs. 5 and 6, a limited play in the sockets 4O which receive the contacts so that the latter may adjust themselves in the socket to accommodate any unevenness or irregularity of the adjacent engaging contact faces. i

The upper ends of the two plungers 16 of each pole of the switch are connected together by a cross-bar 69, which, together with the plungers 16, constitute the yoke. All the cross-bars are connected together by .a bar or beam 70 which extends horizontally above all the tanks. Secured to the upper beam 70. are two vertically movable operating plungers or rods 71, which extend downward between the tanks and are supported and guided for vertical movement by two frames 7 3, supported on the frame 10 between the tanks, each frame being somewhat triangular in shape and being provided at the top with a boss or hub 74 and at the bottom with a boss or hub75 having vertical bores or passageways through which the corresponding plunger or rod 71 is adapted to slide. The switch is adapted to be closed by an electromagnetic motive device, preferably in the form of a solenoid, and is adapted to be opened with an exceedingly quick movement by means of weights and springs which act upon the plungers 71. For this purpose the plungers 71 are provided below the upper bosses 74 with collars 76, which as shown clearly in are secured to the rods by transverse pins 7 7 and between the collars bosses of the frames andsurrounding the plungers 71 are rather heavy coil springs 7 8 which will be compressed when the plungers are drawn downward.

' Secured to the lower side of the frame 10 and below the middle tank 12 are two cast metal plates 79 which form a supporting frame for part of the switch operating mechanism. These plates 79 are provided with bosses or bearings 80 in which is supported a shaft 81 which extends outwardly beyond the bearings of each of the plates 7 9 Fig. 1. Secured or fixed to the outer ends of this shaft 81 are two levers 82, to the outwardly projecting ends of which are secured weights 83, and

the forwardly 0r inwardly pro ecting ends of which are operatively connected to the collars 76 which are secured to the movable plungers 71. In this case the inner end of each lever 82 is connected to the corresponding collar 76 by a pair of links or straps 86.

Secured to the lower sides of the plates 79 is acasing 88 for a switch-closing solenoid- 89 and for a tripping solenoid 90. These solenoids 89 and 90 may be controlled in any suitable manner, one desirable way of doing so in my aforesaid co-pending application of which this application is .a division. The

closing solenoid includes a coil 91 and a core 92 which extends upwardly through the cover 93 of the casing, and this core is connected by a link 9 1 to one arm 95 of a bell-crank lever 96 which is secured to the shaft 81 between the two plates 7 9, so that when the core is drawn into the coil 91, the bell-crank 96, shaft 81 and weight carrying levers 82 will be rocked, swinging the inner ends of the levers 82 downward and the outer ends of the levers and the weights carried thereby upward. The links 86 and consequently the plungers 71 will therefore be drawn downward, compressing the coil springs 78 which surround the plungers 71, and closing the switch. In order that the switch may be held in the closed position, I have provided a toggle consisting of two arms 97 and 98, pivotally connected together by a pin or stud 99,

and the formerbeing connected by means of a pin or stud 100 to an 'arm 101 of the bell-crank lever 96 and the latter being pivotally supported on the two plates 79-by means of a transverse pin orshaft 102 ex:

. tendingbetween the plates. The inner end of arm 98 of the toggle extends beyond the connecting pin 99 and is provided with a notched or hooked portion 103. Thus it will be seen that-when the switch is closed by the solenoid 89, the movement of the bell-crank 96 will cause the arms 97 and 98 7 6 and the lower being that set forth faces, and arranged buffer blocks 113 having just below a straight line between the pins or "centers of movement 100 and 102. Any suitable stop device may be employed for -limiting the movement of the toggle arms toward a straight line. To hold the toggle in this position, I have provided a holding and tripping device consisting of a latch 104: pivoted between the two plates 79 and having at its upper end a roller 105 which is adapted to be engaged by the notched portion 103 of the arm 98 of the toggle and having its lower end directly above a hammer 106 which projects above the cover 93 of the casing and is adapted to be struck and. shifted upwardly .by the core 107 of the tripping solenoid ,90. The latch 10a is normally' held in the position shown in Fig. 2 by means of a smallcoil spring 108, and when the switch is closed by the solenoid 89 and the arms of the toggle are brought nearly in a line, the notched or hooked portion 103 of the toggle arm 98 will be swung above the roller 105 at the end of the latch 104: and will be retained in that position. When, the coil 109 of the tripping solenoid 90 is energized, the hammer 106 will be given a blowby the core 107, the latch will be rocked and the upper end will be swung inward out of engagement with the notched or hooked portion of the toggle arm 98,with the result that the switch will be immediately opened with an exceedingly quick movement by the force of gravity acting on the weights and by the action of the coil springs 78. The arm 98 of the toggle is provided with an extension 110 having a socket 111 in which is adapted to be inserted the end of a suitable bar or lever by'means of which the switch may be closed by hand.

Suitable buffers, are provided for cushioning the. movement of the switch mechanism when the switch is opened, and this buffer mechanism is as follows: At the lower ends of the rods 71 are provided nuts 112 havingv conical or inwardly tapered suron diametrically opposite sides 'of each rod 71 are two hollow v tapered inner ends adapted to be engaged by the tapered portion of the corresponding nut. These buffer blocks are supported on the lower sides of the triangular shaped. frames 73 between pairs of downwardly extending lugs or cars 11 1 and upon cross pins 115 extending between the ears. The blocks have elongated slots 116 which extend in the direction of the lengths of the blocks, and through which the pins 115 loosely pass, so that the blocks may turn or rotate on the pins and also may move longitudinally. Secured on the interior of each of the hollow blocks 1 13 by means of the cross pin 115 is a pin or plug 117 and intermediate the blocksare therefore prevented by these stop 1 rubber blocks 118 to be compressed between the pins or plugs 117 and the closed ends of the buffer blocks. When the rods 71 are moved downward or when the switch is closed, the wedge-shaped nuts on the rods 71 will pass from between the buifer blocks, the latter swinging downward as shown in Fig. 8,'to permit the rodsand wedge-shaped nuts to readily move downward.

It will be seen that on account of the con-' structiori of the switch itself, the particular arrangement of the cooperating contact members and the manner of insulating the same, the quickmovements with which the contactsare separated, and the particular construction and arrangement of the operating mechanism, there is provided a switch in whichdangerous and destructive arcing at the contacts is reduced to a minimum.

Itis to be noted also that access can be readily had to all parts of the switch mechanism even though art of the mechanism is supported on the ower part of the tank.

The movable switch mechanism can be removed as a unit from each tank after the beam 7 0 and the cover are removed, and in case it is necessary to inspect or repair the stationary switchmechanism, the supporting fraine29 and all the apparatus carried thereby, including the switch supporting insulators and the contact mechanism supported by the insulators, canbe simultaneously lifted from the tank by grasping the terminal rods and drawing the same and all the parts connected thereto, upward out of the tank, the insulating barriers 33 and 3 1, being of course; first removed from the tank.

I do not desire to be confined to the exact details, but aim to cover all modifications which do not involve a departure from the spirit and scope of my invention as set forth in the appended claims.

What I claim as new is:

1. In an oil switch, an oil'tank, a casing of insulating material within and spaced from said tank, switch mechanism within said casing, and a plurality of spaced insulating elements between said tank and casing, said. insulating elements having portions lying across said tank between the bottom thereof and said casing.

2. In combination, a plurality of switches each contained in a separate casing, actuating mechanism for said'switches, a support for said casings, and means for adjusting said casings relatively to each other and to said actuating mechanism comprising adjusting means between the lowerpart of each casing and said support and adjustable spacing means between the upper parts of the individual casings.

3. In combination, a plurality of switches, a casing for each switch, a support for said casings, switch operating means supported in fixed relation to said support, and means for adjusting said casings relatively to each other and to said support to properly aline the switch parts, said adjusting means including adjustable spacing devices between the individual casings and independent of said support.

4L. In an oil switch, an oil tank, an insulating support mounted in said tank, a contact holder of conductive material carried by said support, said holder having a base and a portion supported thereby and provided with an extension substantially parallel to the adjacent side of said base and spaced therefrom, said extension being provided with a guidingrecess, a contact in said recess, a spring intermediate the base of said holder and said contact and pressing thelatter away from said base, said spring being in'sertible into operative position from the side of said extension adjacent said base.

5. In an oil switch, an oil tank, a plurality of insulating supports mounted in, said tank, contact holders mounted on said supports,

each holder having a vertical socket, a main contact yieldingly supported therein, and a "pivoted arm embracing said main contact and carrying an auxiliary contact, and a vertically movable' bridging contact member having downwardly projecting ends provided with main contacts adapted to engage the upper ends of the main contacts carried by the holders, and auxiliary contacts adapted to engage the auxiliary contacts carried by the holders.

6. In an oil switch, an oil tank, a plurality of separate insulators mounted in said tank, a contact holder mounted upon the. upper end of each insulator, two of said holders each having a terminal rod connection and a. contact on the same side of the supporting ported so as to be capable of vertical movement, another holder intermediate said two holders having a pair of contacts yieldingly supported, and apair of plungers extending downward into the tank and having bridging conductors provided at their ends with contacts adapted to engage the contacts carried by said holders. I p

7 In an oil switch, an oil tank, a frame 10 mounted in the lower part of said tank, a series of spaced insulators extending upward from said frame and secured thereto, contact holders mounted upon the upper ends of said insulators and being arranged in a row,

5 the holders on the two outer insulators having terminal conductors connected thereto and each having a single main contact yieldingly supported so as to be capable of a slight vertical movement and having a yieldingly supported auxiliary contact, and a third holder on an insulator intermediate the other two insulators, said third holder having two main contacts and two auxiliary contacts all yeldingly supported, a pair of plungers extending downwardly into the tank, bridging conductors, carried by said plunger and having at their lower ends main and, auxiliary contacts adapted to engage the main and auxiliary-contacts carried by said holders.

8. In an oil switch, an oil tank, an insu lating frame mounted in the lower portion of said tank, said frame carrying a plurality of separate insulators, contact holders mounted upon the upper ends of said insulators, terminal conductors extending downward into the tank and connected to the holders on the two outer insulators, each of-said last named holders having a main contact yieldingly supported so as'to be capable of a slight vertical movement, and a pivoted member provided with an auxiliary contact, a' third holder intermediate the outer holders, said third holder having a pair of main contacts yieldingly supported so as to be capable of slight vertical movements, and having a pair of pivoted members provided with auxiliary contacts, vertically movable plungers extending downward into 50 the tank, bridging contact members carried by said plungers and having at their ends main and auxiliary contacts adapted to engage the main and auxiliary contacts of said holders.

55 9. In an oil switch, an oil tank having a cover divided longitudinally into two separable parts, a plurality of insulating supports mounted in said tank, contact holders providedwith contacts secured to said supso ports, a plurality of insulating bushings carried by said cover intermediate the parts thereof, terminal conductors extending downward into the tank through two of said bushings andconnected to two of the contac't holders, a plurality of plungers extendcomprising I mechanism,

ing downward into the tank through two other of said bushings and having bridging contact conductors provided at their lower ends with contacts adapted to engage the contacts carried by the holders associated with said terminal conductors and other of said first mentioned contacts.

10. In combination, in a switch, contact mechanism, switch operating mechanism comprising a longitudinally movable mem- 5 her, cushioning devices for limiting the movement of said member comprising hollow members which are mounted adjacent to and are movable laterally by said longi tudinallymovable member, and a. cushioning medium within each of said hollow-members.

11. In combination, in a switch, contact mechanism, switch operating mechanism a longitudinally movable rod, cushioning devices for said switch mechanism comprising a pair of members mounted on opposite sides of said rod, said rod having meansadapted to move said members outwardly, and an elastic cushioning medium adapted to be compressed by each of said outwardly movable members.

12. In combination, in a switch, contact mechanism, switch operating mechanism comprising a longitudinally movable rod, means for cushioning the movement of said operating mechanism comprising members slidably mounted on opposite sides of said I rod and adapted to be moved outwardly by the same, and elastic devices compressed by the outward movement of saidmembers.

13. In combination, in a switch, contact mechanism, switch operatin mechanism comprising a vertically mova le rod, a tapered member on said. rod, means for cushioning the movement of said mechanism comprising a pair of buffers on opposite sides of the rod in position to be engaged and to be moved outwardly by said tapered member.

14. In combination, in a switch, contact switch operating mechanism comprising a longitudinall movable rod and means for cushioning the movement of 7 said operating mechanism comprising a taered member on said rod, a pair of pivoted and longitudinally movable blocks on opposite sides of said rod in position to be engaged and spread apart by said ta ered member when the rod is moved in one irection, .a relatively stationary member and a cushioning medium within each block.

15. In combination, a frame provided with a supporting platform having one or more angular pro ections extending therefrom, a plurality of oil receptacles supported side by side on said frame, a switch mechanism in each receptacle, and means for spacing said receptaclesand holding the same in osition on the frame comprising adjusta le screws extending through said projection or Correction in Letters Patent No. 1,240,314.

projections on the frame and engaging the sides of the receptacles.

16. In combination, in a multipole switch, a frame, a plurality of tanks supported on said frame, and means for definitely positioning said tanks relative to one another comprising spacing bolts extending between the upper portions of adjacent tanks and screws engaging opposite sides of the lower portions of the tanks.

17. In combination, a multipole switch, a frame, a plurality of tanks supported side by side on said frame, means for holding said tanks in definite positions relative to one another and to the frame comprising set screws engaging opposite sides of the lower portions of the tanks. adjustable rods or bolts extending between the upper portions of adjacent tanks. and adjustable tie rods connecting the upper port-ions of the tanks to the. frame.

18. In combination, in a multipole oil switch, a horizontal frame. a plurality of tanks side by side on said frame. adjustable means between the tanks for holding the same in relatively fixed positions. and adjustabletie rods extending between the upper ends of thetanks and the sides of the frame.

18, 1917, upon the application of H for an improvement in I signed and sealed this 29th d [SEAL] the record of the case in the Patent (Silica I 15.). In a switch, a contact holder of conductive material and comprising a body portion and an extension therefrom, a main contact movable in said recessed portion, an auxiliary contact pivoted to said extension, and yielding means between said main contact and the body. portion of said contact holder for urging said contact away from said holder.

20. In a switch, the con'ibination of a contact support of conductive material and comprising a body portion and a portion supported thereby and spaced therefrom, said latter portion being provided with a guiding recess, a contact in said recess, said contact being insertible in said recess from the side adjacent said body portion, and means for urging said contact away from said body portion.

Milwaukee, \Visconsin, September 3, 1910.

In testimony whereof I aflix my signature, in the presence of two witnesses HERBERT \V. CHENEY.

\Vitnesses:

tnxs. L. In'noN, CLARA E. BENSEL.

, granted September erbert W. Cheney, of Milwaukee, Wisconsin ay of January, A. D., 1918 I R. F. WHITEHEAD,

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