US2169481A - Clamping device - Google Patents

Description

Aug. 15, 1939.

IHIIlllllllllll llllllllllllllllllllllllllll l T. G. A. SILLERS El AL ,169,48

CLAMPING DEVICE Filed Aug. 15, 1936 2 Sheets-Sheet 1 llllllllIllllllllllllllllllllllllllllHlIlllll T. e. A. SILLERS ET AL ,4 1

CLAMPING DEVICE Filed Aug. 15, 1936 2 Sheets-Sheet 2 Aug. 15, 1939.

Patented Aug. 15, 1939 UNITED STATES PATENT OFFICE Michael, West Allis,

Wis., assignors to Allis- Chahners Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application August 15, 1936, Serial No. 96,240

10 Claims.

This invention relates in general to clamping devices and particularly to an improved method of and mechanism for raising or lowering an apparatus to and from a given position and locking or clamping the apparatus while in the given position.

In prior constructions of this nature especially where utilizedin truck type switchgear, it has been customary to move a circuit breaker into and out of a cell, cubicle or enclosure on a truck and to raise the circuit breaker from the truck to its operating position where it is connected to the bus bar structure. In order to solidly clamp the circuit breaker so that the shocks due to operation thereof, which shocks are heavy when the breaker opens on short circuits, are not transmitted to the bus structure, stops have been provided against which the circuit breaker has been held in position by manually operated clamping means while the circuit breaker is in operating position. Such clamping as has been afforded by the prior constructions has the disadvantages of requiring a separate manual operation, of lacking adjustment of the device in the clamped position and failing to provide with limit switches and motors the accuracy necessary to stop the circuit breaker solidly against the stop. These prior clamping devices have also afforded no means other than gravity for exerting a positive downward pull on the breaker when lowering from connected position, so that any binding or sticking of the bus connecting contacts due to corrosion thereof will be overcome.

It is therefore an object of this invention to provide an improved method of and means for clamping a device in position, which avoids the above disadvantages and provides a solution for the above problems.

It is also an object of the present invention to provide in apparatus of the above character a clamping means that automatically becomes effective when the device is raised to or near a given position and automatically releases the device when lowered from a given position.

It is a further object of this invention to provide in apparatus of the above type a clamping means which provides adjustability of the device in the given position.

It is also an object of this invention to provide in apparatus of the above character an automatic clamping means that will transmit a positive force to the device clamped when lowering the same.

It isalso an object of the present invention in apparatus of the abovetypeto provide for moving a device to a predetermined position by an electric motor and to deenergize the motor, by means of limit switches operated in response to movement of the device moved, with sufiicient accuracy that the device becomes automatically clamped in such position.

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

Fig. l is a view of a device clamped in operating position in accordance with the present invention;

Fig. 2 shows the manner in which motive power may be applied to the mechanism shown in Fig. 1;

Fig. 3 is a fragmentary enlarged view of the apparatus of Fig. 1 showing the clamping mechanism in locked position;

Fig. 4 is a fragmentary enlarged View similar to Fig. 3 but showing the clamping mechanism in released position;

Fig. 5 is a top view of Fig. 3 with the circuit breaker removed for the sake of clearness; and

Fig. 6 is a section View taken on the line VIVI of Fig. 5.

Referring now to Fig. l, a device 8, which is shown in the present embodiment as a circuit breaker, is capable of being raised to the position shown where the stud connectors i2 are in conducting relation to the bus connectors H. As indicated in Fig. 2, a number of devices 8 may be held together by channel members 9, so that they may be raised or lowered as a unit. The channel members 9 may be held together by cross members 18 and may be raised and lowered by the power operated screws l4. As shown in Fig. 2, the motive power for the power operated screws l4 may be supplied by the motor 20 through bevel gears, the shaft H, and worm It to the gears 15, which are keyed to the screws I4. A bearing and support for the screws I4 is provided by the members 51 which are suitably fastened to the supporting frame 45. A limit switch 2! is provided for stopping the motor 29 at predetermined positions of the device 8.

In connection with the raising, lowering and clamping in position of truck type switchgear, there are several problems which occur. The lifting mechanism should permit the circuit breaker to be simply and easily disengaged therefrom when it is lowered sufiiciently to rest on the truck or floor. When the circuit breaker is in operating position, that is, when it is raised so as to be connected to the bus bar structure,

the circuit breaker should be clamped against upward movement due to the shocks which occur when the circuit breaker opens under short circuit conditions. These shocks may be of a very serious nature and should not be transmitted to the bus bar structure which is relatively delicate. When, in prior constructions, an attempt was made to raise'the circuit breaker against a definite fixed stop so as to solidly clamp it against movement, the accuracy necessary for such operation could not be obtained with limit switches acting on the motor, for the motor would either not hold the circuit breaker sufiiciently tight against the stop or would overtravel and thereby shear 01f the stop or injure the raising mechanism. In prior constructions the circuit greaker has been bolted or clamped solidly in position, but this necessitates a separate manual operation. The present invention avoids the disadvantages of the prior art constructions and solves the above problems by the improved method and structure shown in the drawing and described herein.

The clamping mechanism is denoted generally by the numeral 23. This clamping mechanism 23 comprises essentially a threaded nut member 24 which is raised and lowered by the rotation of the screw 44. As is clearly shown in Fig. 4, the nut 24 is provided with an extension 25 which has thereon a projection 26 supporting the circuit breaker 8 by means of the channel members 9. A locking member 28 is provided which automatically clamps the circuit breaker against movement while the circuit breaker is in the position shown in Fig. 1. The member 28 is mounted on the projection 25 by means of the keyed pin 21 and is rotatable relative to the projection 25 about the center of the pin 21. The upper end of the clamping member 28 is provided With projecting lugs 29 which cooperate with an extension 35 of the channel member 9 when the member 28 is forced into the locking position shown in Fig. 3.

The clamping member 28 is forced into locking position only when the circuit breaker is in or near connected or operating position and this operation is automatically provided by means of the large roller 35 and the cam surfaces 39 and 48 of the member 5|, with which the roller 36 cooperates. The member 5| is bolted rigidly to the supporting frame 45, and as the circuit breaker 8 is being raised to connected position, the large roller 36 comes into contact with the cam surface 40 as shown in Fig. 4. As the circuit breaker is raised further, the cam surface 49 forces the member 28 in a counter-clockwise direction about the pin 2! until it is in the position shown in Fig. 3 with the roller 36 on the cam surface 39 and the projecting lugs 29 cooperating with the channel 35 toclamp the channel member 9 against the projection 26. The two rollers 36 are supported in the projections 55 of the member 28 by means of pins 31 as is more clearly shown in Fig. 5.

Also mounted on one pin 3 is a small roller 38 which functions in. cooperation with the member 52 having cam surfaces 46 and 41, when the circuit breaker 8 is being lowered from operative position, to force the locking member 28 into the releasing position shown in Fig. 4. When the circuit breaker 8 is being lowered from the position shown in Fig. 3, the small roll 38 bears on the cam surface 46 of the member 52, thus rotating the member 28 about the pin 21 in a clockwise direction until it is in the position shown in Fig. 4

and the lugs 29 are released from clamping the channel 35. When the first lowering action takes place the lugs 29 transmit to the channel 35 a positive force which forces the breaker 8 downwardly and thereby loosens the contacts l2 from the contacts II. This is important where there may be corrosion between contacts I! and i2 such that will cause the lighter weight circuit breakers to stick in connected position if the action of gravity alone is utilized for lowering.

' The cam surface 4'! of the member 52 functions to position the member 28 when the circuit breaker is being raised. As the circuit breaker is raised, the small roll 38 bears on the surface 41, if the member 28 is not already in its releasing position, and thereby moves it into releasing position so that the large roll 36 may bear on the cam surface 40.

The present invention provides a considerable distance wherein the circuit breaker is locked and solidly clamped in position. In raising the circuit breaker 8 to position, the clamping member 28 is in locking position as soon as the roll 38 passes from the cam surface 40 to the cam surface 39. by an automatic means which is well within the accuracy obtainable by a motor and limit switches. A projection 39 on the member 28 is provided for cooperation with a lug 34 onv the member 24 so that when the circuit breaker is below a position where either of the rollers cooperate with their respective cam surfaces, the member 28 cannot rotate in a counterclockwise direction sufiiciently so that the small roll 38 can move to the left of the cam surface 47, as viewed 5 in Fig. 4 of the drawings.

In order to provide for a manual adjustment of the circuit breaker position the threaded nut 24 is constructed as shown in Fig. 6. A sleeve 48 is threaded on to the screw l4 and this sleeve 48 is keyed to the member 24 by a key 53 thereby allowing for relative longitudinal motion between the nut 24 and the sleeve 48, the key 53 preventing relative rotational movement between these two members. Relative longitudinal movement between the members 24 and 48 is provided for by the two threaded members 49, which are threaded into the nut 24. These members 49 are carried loosely on the screw l4 and bear against either end of the sleeve 48 and by movement of these threaded members 49 the nut 24 may be raised or lowered to obtain a fine adjustment of position of the circuit breaker. As shown in Fig. 2 a pulley 22 is provided on the shaft 55 as a means of manual operation of the shaft 56 or for manual adjustment for the position of the circuit breaker 8. A chain or cable may be applied to the pulley 22 to manually rotate the shaft 55.

Although but one embodiment of the present invention has 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 combination, a device, means for raising said device to a given position, means for clamping said device against movement independent of movement of said raising means, and actuating means for said clamping means operable in response to the raising of said device substantially to said given position to lock said clamping means in clamping position.

This construction allows solid clamping 2. In combination, a device, means for raising said device to and lowering said device from a given position, means for clamping said device against movement independent of movement of said raising and lowering means, and means operable in response to the raising of said device substantially to and the lowering of said device substantially from said given position for positively actuating said clamping means into and out of clamping position.

3. In combination, a device, means for raising said device to and lowering said device from a given position, said means including a support for said device against downward movement thereof independent of movement of said raising and lowering means while being raised to and lowered from said given position, and means operative in response to movement of said device for locking said device against upward movement thereof independent of movement of said raising and lowering means at all times when substantially in said given position.

4. In combination, a device, means for raising and lowering said device to and from a given position, means operative in response to the raising of said device to said given position to lock said device against upward movement thereof independent of movement of said raising and lowering means and operative in response to the lowering of said device from said given position to release said lock against said upward movement, and means for positively actuating said last said means to locking and unlocking positions.

5. The combination of a circuit breaker of the type provided with an operating position in which auxiliary contacts are connected and further provided with means for raising and lowering said circuit breaker to and from said operating position, with a means for clamping said circuit breaker against movement due to circuit breaking operation thereof, and actuating means for said clamping means operable in response to movement of said circuit breaker near said operating position.

6. In combination, a circuit breaker provided with an auxiliary contact, a second auxiliary contact, a. structure supporting said circuit breaker comprising means for raising said circuit breaker relative to said structure to and lowering said circuit breaker relative to said structure from a position in which said auxiliary contacts coopcrate to make a circuit, a clamp for said circuit breaker movable therewith when raised and lowered and movable relative to said circuit breaker to clamping and releasing positions, and means comprising a member supported by said structure providing control of the clamping and releasing movement of said clamp.

7. In a truck type switchgear, a circuit breaker adapted in one position to be connected to a bus structure and in another position to be disconnected therefrom, means for moving said circuit breaker from said one position to said another position, means controlled by movement of said circuit breaker to said one position for locking said circuit breaker against transmittal of movement thereof, due to circuit breaking operation, to said bus structure, and means for releasing said look only upon movement of said circuit breaker a predetermined distance toward said another position.

8. In a switchgear, a circuit breaker, a bus structure, cooperat ng disconnect contacts carried by said circuit :eaker and said bus structure, means for raising said circuit breaker to a position in which said contacts are connected, means for clamping said circuit breaker against movement thereof due to circuit breaking opera tion, means operable by movement of said circuit breaker for controlling said clamping means, said means controlling said clamping means to release said circuit breaker only after movement thereof sufiicient to prevent sticking of said contacts.

9. In a switchgear, a circuit breaker, a disconnecting switch, a supporting structure, means carried by said structure for raising said circuit breaker to close said switch, operating means for said raising means comprising a motor, a limit switch for deenergizing said motor when said circuit breaker is raised sufliciently to close said disconnecting switch, and means operable in response to raising of said circuit breaker for clamping said circuit breaker to said structure during rotation of said motor.

10. In a switchgear, a circuit breaker, disconnecting switch contacts, a supporting structure, means carried by said structure for raising said circuit breaker to close said contacts and lowering said circuit breaker to open said contacts, operating means for said raising and lowering means comprising a motor, a limit switch for deenergizing said motor when said disconnecting switch contacts are closed, means operable in response to raising of said circuit breaker for clamping the same during rotation of said motor whereby circuit breaker movement due to circuit breaking operation is prevented, and means operable in response to lowering of said circuit breaker for releasing said clamping means.

THOMAS G. A. SILLERS. JOHN H. MICHAEL.

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