US2482305A - Clamped switch - Google Patents

Description

p 9 1949- B. voLGovsKoY ET AL 2,482,365

CLAMPED SWITCH Filed June 22, 1945 s Sheets-Sheet 1 38mm QD/OXQOM/DXQOM @LWon w Q. Mama/a Sept; 20, 1949'.

Filed June 22, 1945 B. VQLGOVSKOY ET AL 2,482,305

CLAMPED SWITCH 3 Sheets-Sheet 2 206 20 J fly 20a, J 25 25 Sept. 20, 194 s. VOLGQVSKOY mm,

CLAMPED SWITCH Fue June 22, 1945 3 Sheets-Sheet 3 fill/III Patented Sept. 20, 1949 CLAMPED SWITCH Boris Volgovskoy,

Wauwatosa,

and Allan G.

Halter, Milwaukee, Wis., assignors to Allis- Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application J1me 22, 1945, Serial No. 600,988

Claims. 1

This invention relates in general to improvements in electric switches and relates particularly to disconnect switches havin considerable current carrying capacity.

The advantages of high contact pressure in electric switches carrying heavy currents are well recognized. In such switches it is not feasible to obtain the desired contact pressure by resiliency of contact structure, because of difficulty in opening and closing the switch contacts. In prior art disconnect switches of the clamped type, in which the fixed and movable contacts are tightly clamped together after the switch is in closed position, cooperable screw threaded members have been utilized to provide the clamping action.

In these prior art switches, the cooperating screw threaded members have been relatively rotated to provide a nut and bolt clamping action on the switch contacts when the nut is tightened on the bolt and to release the clamping when the nut is loosened. These prior art switches have several disadvantages: (1) the amount of pressure on the contacts is dependent ((1) upon exact position of the operating handle turning the clamping nut, (b) the lost motion and frictional forces in the operating mechanism, and (c) the amount of wear in the thread on the cooperating clamping members; (2) the clamping pressure can not be adjustabl?! preset while the contacts are in released position; and (3) the switches can not be clamped in the open position.

It is therefore an object of the present invention to provide an improved switch of the above clamped type that avoids one or more of the above disadvantages.

It is also an object of the present invention to provide an improved clamp type of disconnect switch in which a preset clamping pressure is provided by a spring member.

It is also an object of the present invention to provide a disconnect switch with an improved contact clamping means in which the clamping pressure is independent of the exact position of the threaded members utilized in the application and removal of the clamping pressure.

It is also an object of the present invention to provide an improved clamp type of disconnect switch in which a spring is utilized to provide the contact clamping pressure and in which cooperable threaded members are utilized to release the clamping pressure.

7 It is a further object of the present invention to provide an improved clamp type of disconnect switch in which a spring member is utilized for applying a predetermined preset clamping pressure, and in which the place of application of such pressure is transferred from one place to another to provide the clampin or releasing action for the switch members.

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawing in which:

Fig. l is an end view of a disconnect switch embodying the present invention;

Fig. 2 is a plan view of the switch shown in Fig. l; 1

Fig. 3 is a fragmentary top view of a portion of the switch taken along the line III-I11 of Fig. 2;-

Fig. 4 is a detailed view of the locking plate of the switch shown in Figs. 1 and 2;

Figs. 5, 6 and '7 are partial end views showing various operating positions of the device of Figs. 1 and 2; Y I

Figs. 8 and 9 are sectional views taken on the line VIIIVIII of Fig, 3 showing different operating positions of the device.

Fig. 10 illustrates a modification of the invention; and

Figs. 11, 12 and 13 illustrate details and other operating positioned the device shown in Fig. 10.

As illustrated in Figs. 1 to 9, the present invention may be embodied in a switch comprising generally a base plate I 5, fixed contacts l6 and I! supported thereon, and one or more movable knife blade contacts such as 2!! and 2|. The knife blades 20 and 2|, as shown more in detail in Figs. 8 and 9, are provided with movable means, here shown as a shaft 22 having a threaded portion 23 and having an enlarged part forming a shoulder 24. A second movable means, here shown as a nut or a, threaded member 21, cooperable with the threaded portion 23 and operable by a lever 28, is rotatable relative to the shaft 22 to move the shoulder 24 from the position shown in Fig. 9 to the position shown in Fig. 8.

Resilient means, such as a cupped shape spring or resilient member 25, adjustably held by suitable means, here shown as anut 26, applies a pressure betweenthe contact 20 and the shaft 22, and with the nut 2! in the position shown in Fig. 9-, such spring pressure is applied to both sides 20a, Zlib, of the contact 20. With the parts in the position shown in Fig. 9, a predetermined pressure of the spring 25 may be preset by suitably adjusting the nut 26.

position, the pressure of the spring 25 is applied at its outer circumference to the left hand side of switch blade 28 and is applied at its center, through the nut 26, the shaft 22, and the nut 21 to the right hand side of the switch blade 2|. blades and 2| are tightly clamped against the non-adjacent faces of fixed contacts [6 or H Thus, as shown in Fig. 8, the two switch that may be therebetween. The movement of the shoulder 24, as shown in Fig. 8, has been exaggerated in the interest of clarity'of illustration. v

By utilizing the spring 25, rather than relativelythreaded members, to provide the contact clamping pressure, several advantages are gained. The desired clampingpressure may be accurately adjustably preset by means of the nut 26, while the contacts are in the released position. V

Thecontact clamping pressure is substantially uniform for each operation of the switch to the position shown .in Fig. 1, the pressure being abruptly applied by movement of the handle 28 to the clamping position. Since full clamping pressure obtains when the shoulder 24 moves out of contact with the blade 20, such pressure is only negligibly increased by the limited further movement of the nut 21 to the fully clamped position. Itfollows that the clamping pressure substantially equals the preset pressure of the spring 25, since upon rotary movement of the nut 21, the shoulder 24 of the bolt 22 moves only a short distance linearly to increase the fiexure of the spring 25 only to a negligible extent. The movement of shaft 22 from the position shown in Fig. 9 to that shown in Fig. 8 has been exaggerated for clarity of illustration.

By utilizing spring pressure for clamping, only a small operating force is necessary-to effect the clamping action, thereby avoidingthe relatively large force required when screw threaded members are utilized to provide a nut and bolt clamping. In the latter case, the operating force must be'sufficiently great to provide a slight deformation of the contact, but in an embodiment of the present invention, the clamping is effected by a simple transfer of the point of application of a substantiall constant preset spring pressure that has been suitably established by a simple positioning of the adjusting nut 26.

Referring to Figs. 3 and '7 the operating lever 28' has an extension 29 thereon which is connected by. a link 30 to a similar extension 29 on the operating member of the lower contact. All four of the operating members and clamping structures shown in Fig. l are similar in structure and operation and, therefore, only one is described in detail. If desired, additional linkages and additional sets of contacts with similar operating and clamping mechanisms may be operated by the single operating member. This could not practically be done if resiliency of contacts were depended upon for contact pressure.

Bolted on to the upper contact l6 is a locking plate 40, shown in detail in Fig. 4, that is utilized in providing a positive lock against the undesired opening of the switch blades by magnetic forces caused by heavy current carried by the switch. A pin 42 supported in the extension 29 cooperates with the slot in the plate 40 to lock the switch in closed position.

The pin 42 also functions, in cooperation with a latching member 43, to prevent relative motion between the operating lever 28 and the switch blade 23' under certain circumstances. The latch member 43 is biased into the position shown in Fig. '7 by means of a spring 45. In the position shown in Fig. '7, the lower edge of the slot in the upper end of the latch 43 cooperating with the pin 42, prevents counterclockwise movement of the operating lever 28 relative to the switch blade 20. An extension 46 isprovided onthe latch 43 which provides a convenient means of applying pressure to the latch 43 against the bias of spring 45, to move the latch 43 in a clockwise direction about its pivot, so that the lever: 28 can be moved, relative to the switch blade 20, in a counterclockwise direc tion.

The operating handle'28 is provided with an anti-vibration latching means preventing relative movement between the lever 28 and the blade 28 when the switch is in'the positionyshowniii Fig.1. As shown more clearly'in Fig. 5, a latch 32 is mounted to rotate on a'pin 48 and is biased to the latched position bymeans of a spring'33. The latch 32 cooperates with a rod l ll utilized to hold the switch blades in relative position, to prevent pressure "releasing movement of the lever 28 unlessthe handle 3| has been moved to the position shown in'Fig."5. J

A latch operating member 35 is pivotally supported on a pin 6| in the lever 28 andhas a pin and toggle connection to a link 36 pivoted ona pin 62. The link 36 cooperates atitsflower end with an adjusting screw'34 in the latch member 32. The latch operating member 35has the handle 3| supported therebetween on a pin31', the ends of which are movable in slots 39 in" the switch lever 28. V I M .When the switch is in the closed position shown in Fig. 1, the clamping mechanism is in the position shown in Fig. 8 whereby the blades 20 and 2| are tightly clamped against the'fix ed contacts l6 and I1. Movement of'the operating handle 3| from the position shown in Fig. 1 to the position shown in Fig. 5, lifts the latch member 32 away from the pin 19, thereby permitting movement of the operating lever 28 in a clockwise di rection to the position shown in Fig. 6. This operation moves the nut 21 so that the clamping structure takes the position shown in Fig. 9 whereby the clamping pressure of the spring on the contacts 20 and 2l is re1eased in that the clamping pressurepreviously applied to the right side of contact 2| has been transferred to the right side of contact 20 thereby clamping only con tact 20. g V

The above described movement of the operating handle moves the pin 42 from the position shown in Fig. 5 to the position shownin Fig. ;6 where it is clear of the slot 4!. Further pressure applied to the operating handle 3| moves the switch blade 20 and the operating lever 28 as a unit about its pivot at the lower contact I! to the position shown in Fig. '7 in which the switch is open.

If it is desired to clamp the switch in the position shown in Fig. '7 so that it may beheld in its open position,-the latch 43 is rotated in a clockwise direction-about its pivot. This movement can be effected by pressure of a finger on the extension 45. Releasing of the pin 42 by the latch 43 permits relative counterclockwise movement of the operating lever 28 relative to the blade 23 until the operating member 28 and the blade 20 take the relative position shown in Fig. 1, whereby the switch is clamped in open position.

A modification of the above described clamping means is shown in Figs. 10, 11, 12 and 13, in which a clamping shaft 50 has a flange 5| and a square section 52. A member 51 is supported concentrically of the shaft 58 for axial movement relative thereto. The member 51 has three pins 55 extending therefrom which pins 55 extend through apertures 56 in the flange 5|. Rotation of the nut 21 relative to shaft 50 transfers the pressure provided by the spring 25, so as to provide clamping and releasing action. As shown in Fig. 10, the pressure provided by the spring 25 is transmitted from one side of the spring blade 20 through the shaft 51) and the flange 5| to the opposite side of switch blade 2!, thereby clamping the blades 28 and 2| against the fixed contact I6.

Although but two embodiments of the present invention have been illustrated and described it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In an electric circuit maker and breaker,

first and second relatively movable contacts for making and breaking a circuit, a spring member, first movable means for flexing said spring membar to a predetermined extent against said first contact to clamp said first contact between said means and said spring member under a predetermined pressure, and second movable means cooperable with said spring member and said second contact for varying the fiexure Of said spring member from said predetermined extent to clamp said contacts together and to unclamp said first contact from between said first means and said spring member.

2. In a circuit maker and breaker, a fixed contact, a movable contact engageable with said fixed contact, resilient means positioned adjacent one of said contacts, a member extending through both of said contacts and including a part for pressing against said movable contact when in a predetermined position, means including said resilient means for resiliently pressing said part against said movable contact to release said contacts for unimpeded relative movement therebet-ween, said member including retaining means cooperating with said resilient means for clamping said contacts together upon release of the pressure between said part and said movable contact.

3. In a circuit maker and breaker, first and second relatively movable contacts, a shaft carried by one of said contacts, a shoulder on said shaft, a member threaded on said shaft, a resilient member, and means including means for selectively moving said threaded member in a predetermined direction to clamp said contacts between said resilient member and said threaded member to prevent relative movement of said contacts and in another direction to press said shoulder against 6 member for releasing said contacts for unimpeded relative movement therebetween.

4. In a circuit maker and breaker, first and second relatively movable and engageable contacts, a resilient member, means for flexing said resilient member with a predetermined pressure for clamping one of said contacts while said one of said contacts is in the open position, and means for clamping both said contacts with a predetermined pressure when said one of said contacts is in the open position.

5, In combination in an electric switch, a fixed contact, a contact movable relative to said fixed contact to open and close a circuit, a resilient member, means includin said resilient member for abruptly applying a predetermined and preset clamping pressure to clamp said contacts against relative movement for all positions of said movable contact, and means for abruptly applying said clamping pressure to clamp one of said contacts and unclamp said contacts.

6. In a circuit maker and breaker, a pair of contacts movable into and out of mutual engagement for making and breaking a circuit, a shaft extending through one of said contacts, a shoulder on said shaft, a member threaded on said shaft, a resilient member, and means including said shoulder on said shaft and said threaded member for clamping one of said contacts between said resilient member and said shoulder for relative movement of said contacts and for clamping said contacts between said resilient member and said threaded member against relative movement of said contacts.

'7. In a circuit maker and breaker, a pair f contacts movable into and out of mutual engagement for making and breaking a circuit, a shaft carried by one of said contacts, a resilient member carried by said one of said contacts, and

i means interconnecting said shaft and said resilient member to cause said shaft and said resilient member to clamp said one of said contacts therebetween when said contacts are in a mode termined relative position and to clamp saii contacts together when said contacts are in another predetermined relative position.

8. In combination in an electric switch, a fixed contact, a contact movable relative to said fixed contact, means for moving said movable contact into and out of conductive relation with said fixed contact, a resilient member, a shaft connected to said resilient member and axially translatable to a predetermined first position for clamping said movable contact between said shaft and said resilient member, and means including said shaft and said contact moving means for axially translating said shaft from said first position to a predetermined second position for clamping said movable contact between said fixed contact and said resilient member, said shaft passing through said fixed contact and said movable contact when said contacts are in mutually conductive relation.

9. In an electric circuit maker and breaker, first and second relatively movable contacts for making and breaking a circuit, a spring member, means including first movable means for flexing said spring member to a predetermined extent against said first contact to clamp said contacts together between said means and said spring member under a predetermined pressure, and second movable means cooperable with said spring member and said first contact for varying the fiexure of said spring member from said predetermined extent to unclamp said contacts from between said first means and said spring mem-: her and to clamp said first contact between said second means and said spring member.

10. In a circuit maker and breaker, a pair of relatively movable contacts, a shaft carried by one of said contacts, a shoulder on said shaft, a nut threaded on said shaft, a spring member, a lever for causing relative movement of said contacts, said lever being connected with said nut for selectively moving said nut in a predetermined direction to clamp said contacts between said spring member and said nut to prevent relative movement of said contacts and in another direction to press said shoulder against said one of said contacts to clamp said one of said contacts between said shoulder and said spring member for releasing said contacts for unimpeded relative movement therebetween. 7

' BORIS VOLGOVSKOY. ALLAN C. HALTER.

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

UNITED STATES PATENTS

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