Transfer switch - Patent Review 5397868

We claim:

1. Apparatus for transferring a power-consuming load reversibly between a pair of electric circuits, the apparatus comprising:

a pair of switch devices respectively associated with the pair of electric circuits;

each switch device having a handle movable between extreme positions, and the switch devices being disposed such that the handle of each switch device moves reversibly towards and away from the other switch device;

a pair of heads, each head respectively associated with one of said switch devices and each head having opposed abutment surfaces removably receiving the handle of the associated switch device between the abutment surfaces;

a drive input including a grip operable in a cyclical stroke, the grip having a gripping portion permitting a handhold for manual operation thereof along the stroke;

supporting means, extending between and fixed relative to the switch devices, movably supporting the heads and grip,

drivable means, driven by the drive input, coupled to the heads for driving the abutment surfaces against the handles to move the handles in response to the stroke of the grip; and,

unidirectional means, associated with the drivable means, permitting the handles to advance and return progressively between the extreme positions and for opposing movement of the drivable means in the direction opposite to the progressive advance of the drivable means at handle positions intermediate the extreme positions.

2. The apparatus of claim 1, wherein:

the switch devices are operative such that operating the grip opens one switch device before closing the other switch device to ensure that the power-consuming load is isolated from the electric circuit associated with said one switch device before transfer to the electric circuit associated with said other switch device.

3. The apparatus of claim 1, wherein:

the grip comprises a pivoted lever arm that is operable pivotally between advanced and retracted positions.

4. The apparatus of claim 1, wherein:

the unidirectional means comprises a ratchet and pawl assembly permitting rotation of the drivable means in one direction and opposing rotation in the direction counter to said one direction.

5. The apparatus of claim 1, wherein:

each head includes a pair of elongated pins disposed in a rigidly spaced parallel relationship;

the pins have outer surface portions between opposite ends;

the abutment surfaces are defined by outer surface portions of the elongated pins;

the supporting means includes two pair of spaced flanges, each pair being respectively associated with one of the pair of switch devices, the flanges of each pair being disposed on opposite sides of the handle of the associated switch device; and,

each flange has an arcuate opening slidably receiving one of the opposite ends of the pins to define such a path for the head that the abutment surfaces are maintained at a substantially constant relative position on the handles as the handles are moved between the extreme positions.

6. The apparatus of claim 1, wherein:

the drivable means includes a crank turning about a rotation axis in response to the stroke of the grip and two links, each link having a proximal and distal end; and,

the proximal ends are driven in a circular path by the crank and each distal end is respectively coupled to one of the heads.

7. The apparatus of claim 1, wherein:

the pair of switch devices are one of a pair of molded-case switches and a pair of molded-case circuit breakers.

8. The apparatus of claim 1, wherein:

the drive input includes an electric motor for driving the drivable means.

9. A manually-operable device coupled to a pair of circuit components; each circuit component having a handle, protruding from a generally planar surface, movable between operative positions; the device comprising:

a pair of heads;

each head respectively associated with one of said circuit components and each head having opposed abutment surfaces removably receiving the handle of the associated circuit component between the abutment surfaces;

a grip operable in a cyclical stroke, having a gripping portion to permit a handhold for manual operation thereof;

drivable means, driven by the grip, coupled to the heads for driving the abutment surfaces against the handles to move the handles between the operative positions in response to the stroke of the grip; and,

a base, clapped together with the generally planar surfaces of the circuit components in a releasably fixed relationship, movably supporting the grip and movably supporting the heads such that the heads maintain a substantially constant relative position on the handles as the handles are driven between the operative positions.

10. The device of claim 9, wherein:

the grip comprises a pivoted lever arm that is operable pivotally between advanced and retracted positions.

11. The device of claim 9, wherein:

each head includes a pair of elongated pins disposed in a rigidly spaced parallel relationship;

the pins have outer surface portions-between opposite ends;

the abutment surfaces are defined by outer surface portions of the elongated pins;

the base includes two pair of spaced flanges, each pair being respectively associated with one of the pair of circuit components, the flanges of each pair being disposed on opposite sides of the handle of the associated circuit component; and,

each flange has an arcuate opening slidably receiving one of the opposite ends of the pins to define such a path for the head that the abutment surfaces are maintained at the substantially constant relative positions on the handles as the handles are driven between the operative positions.

12. The device of claim 9, wherein:

the drivable means includes a crank and a ratchet and pawl assembly permitting the crank to turn in one direction and opposing turning of the crank in the direction counter to said one direction.

13. The device of claim 9, wherein:

the base is attachable to a pair of circuit components comprising one of a pair of circuit interrupters, a pair of molded-case circuit breakers, a pair of molded-case switches, and a pair of motor contactors.

14. Apparatus for transferring a power-consuming load reversibly between two electric circuits; the apparatus comprising:

two switch devices, respectively associated with the two electric circuits, disposed fixed relative to each other;

each switch device having a handle pivotal between operative positions;

a pair of heads, each head respectively associated with one of the two switch devices and each head having opposed abutment surfaces removably receiving the handle of the associated switch device between the abutment surfaces;

a grip operable in a cyclical stroke, having a gripping portion permitting a handhold for manual operation thereof;

drivable means, driven by the grip, coupled to the heads for driving the abutment surfaces against the handles to move the handles between the operative positions in response to the stroke of the grip;

supporting means, extending between and fixed relative to the switch devices, movably supporting the grip;

two pair of spaced-flange portions, each pair of spaced-flange portions respectively associated with one of the two switch devices, the spaced-flange portions being disposed on opposite sides of the handle of the associated switch device; and,

each flange portion having an arcuate opening and each head being coupled to one pair of spaced-flange portions at the arcuate openings such that the abutment surfaces are guided in an arcuate path about axis that is coincident with a pivot axis defined by the pivoted handle of the associated switch device.

15. The apparatus of claim 14, wherein:

the switch devices are operative such that operating the grip opens one switch device before closing the other switch device to ensure that the power-consuming load is isolated from the electric circuit associated with said one switch device before transfer to the electric circuit associated with said other switch device.

16. The apparatus of claim 14, wherein:

the grip comprises a pivoted lever arm that is operable pivotally between advanced and retracted positions.

17. The apparatus of claim 14, wherein:

each head includes a pair of elongated pins disposed in a rigidly spaced parallel relationship;

the pins have outer surface portions between opposite ends;

the abutment surfaces are defined by outer surface portions of the elongated pins; and,

the elongated pins have opposite end portions that protrude into the arcuate openings in the flanges.

18. The apparatus of claim 14, wherein:

the drivable means includes a crank turning about a rotation axis in response to the stroke of the grip and two links, each having a proximal end and distal end; and,

the proximal ends are driven in circular paths by the crank and each distal end is coupled to one respective head.

19. The apparatus of claim 18, wherein:

the drivable means includes a ratchet and pawl assembly permitting the crank to turn in one direction and opposing turning of the crank in the direction counter to said one direction.

20. The apparatus of claim 14, further comprising:

the two switch devices comprise one of two molded-case circuit breakers and of two molded-case switches.

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CROSS-REFERENCE TO RELATED APPLICATIONS

The subject matter of this application Ser. No. 08/127,919 is related to subject matter of a copending, concurrently-filed application entitled "HANDLE ACTUATOR FOR A CIRCUIT INTERRUPTER HANDLE", by inventors George A. Smith, Thomas K. Fogle, and Mark L. Lotzmann (attorney docket number 57,980) and previous copending application Ser. No. 874,861, now U.S. Pat. No. 5,274,206, filed Apr. 28, 1992, entitled "SPRING CHARGING MECHANISM FOR CIRCUIT BREAKERS AND TRANSFER SWITCHES", by inventor Stanislaw A. Milianowicz, the latter application being incorporated herein by this reference. Both of the above-mentioned applications are assigned to the assignee of the present application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the field of transfer switches, and in particular concerns a transfer switch mechanism for transferring a power-consuming load reversibly between a pair of electric circuits.

2. Prior Art

Transfer switches are known in the art. Transfer switches operate, for example, to transfer a power consuming load from a circuit with a normal power supply to a circuit with an auxiliary power supply. Applications for transfer switches include stand-by applications, among others, in which the auxiliary power supply stands-by if the normal power supply should fail.

A transfer switch typically comprises a pair of circuit interrupters combined with a drive input and a linkage system. The preferred types of circuit interrupters have been the molded-case switches and molded-case circuit breaker type because these types are commercially available in a wide array of sizes and are relatively economical compared to other options. The preferred type of drive input depends on the application for the transfer switch. Usually motors are preferred, but other times there is a clear preference for manually-operated mechanisms.

As for the linkage system, there is a great variety in the prior art, and in all their variety known linkage systems are relatively involved and complex. The linkage system extends from the drive input to the handle of the circuit interrupter. Its function is to couple the drive input with the handle of the circuit interrupter so that drive force from the drive input is translated into position changes between progressive positions in the handle. Examples are shown by the U.S. Pat. Nos. 5,081,367--Smith et al., 4,760,278--Thomson and 4,398,097--Schell et al.

While known transfer switches include motor or manually-operated linkage systems for operating circuit interrupter handles, known linkage systems are deficient for numerous reasons. They generally are deficient in providing adequate mechanical advantage. Large circuit interrupters, for example, may require a 150 to 300 pound force to operate the handle between the CLOSED and OPEN position. Such handles are very difficult for electricians to operate without some kind of mechanical advantage.

Known motor or manually-operated linkage systems typically have a handle-engaging joint between the distal end and the handle, but the known joints are not adequately stiff. The joints are prone to twisting between the handle and the joint as the handle requires relatively greater force for operation. Twisting is likely to cause inelastic parts to fail or elastic parts to deform.

Furthermore, known motor or manually-operated linkage systems fail to incorporate any mechanism for enabling the advance of the circuit interrupter handles in short increments, without losing forward progress.

Further still, known motor or manually-operated linkage systems involve relatively elaborate mounting structures to couple together with commercially standard molded-case circuit switches and/or molded-case circuit breakers. Indeed, the known motor or manually-operated linkage systems characteristically are relatively costly and complicated structures to manufacture. What is needed is an improvement which overcomes the deficiencies in the prior art.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a transfer switch mechanism for gaining a mechanical advantage in the operation of a handle of a circuit interrupter.

It is another object of the invention to provide a transfer switch mechanism comprising a crank coupled to a handle of a circuit interrupter and a manually-pumped lever coupled to the crank for selectively operating the handle.

It is another object of the invention to provide a transfer switch mechanism comprising a crank coupled to a handle of a circuit interrupter and a ratchet assembly constraining the rotation of the crank to a single direction of rotation.

It is another object of the invention to provide a transfer switch mechanism for operating a handle of a commercially standard molded-case circuit switch or molded-case circuit breaker, wherein the transfer switch mechanism includes a planar base for clapping together with a planar surface of the switch or circuit breaker in a releasably fastened relationship.

It is another object of the invention to provide a transfer switch mechanism comprising a pair of spaced and opposed abutment surfaces for closely fitting opposite sides of a handle of a circuit interrupter, wherein the abutment surfaces drive against the handle to drive the handle between progressive positions.

It is another object of the invention to provide a transfer switch mechanism comprising a crank coupled to a drive input and a handle actuator for operating the handle of a switch or circuit breaker, wherein the crank and handle actuator are coupled in an arrangement that precludes twisting between the handle and the handle actuator.

It is another object of the invention to provide a transfer switch mechanism comprising a drivable crank and a driven handle actuator coupled to the crank in an arrangement that precludes twisting between the handle and the handle actuator, wherein the crank and handle actuator are coupled by a connecting rod that moves in a plane of symmetry through the handle.

It is another object of the invention to provide a transfer switch mechanism comprising a handle actuator for operating a pivotal handle and a connecting rod coupling the handle actuator with a drive input, wherein the connecting rod generally reciprocates linearly along a tangent of an arc about an axis that is coincident with a pivot axis defined by the pivotal handle.

It is another object of the invention to provide a transfer switch mechanism comprising a drivable handle actuator for operating a pivotal handle, wherein the lines of action (which are defined by the forces transmitted from the handle actuator to the handle) are coincident with tangents of an arc about a pivot axis defined by the pivotal handle.

It is another object of the invention to provide a transfer switch mechanism comprising a drivable pair of spaced and opposed abutment surfaces closely fitting opposite sides of a pivotal handle for driving against the handle to move the handle between progressive positions, wherein a substantially constant relative position is maintained between the handle and abutment surfaces while the handle is driven between progressive positions.

It is another object of the invention to provide a transfer switch mechanism for operating a handle of a circuit interrupter, wherein the transfer switch mechanism is inexpensive and easy to manufacture, yet strong and durable.

These and other objects are accomplished by a transfer switch mechanism according to the invention for operating the handle of a pair of circuit components like a circuit interrupters, molded-case circuit breakers, molded-case switches, and motor contactors. The transfer switch mechanism comprises a base fixed relative to the circuit interrupters. A lever arm is movably coupled to the base and is operable in a cyclical stroke between an advanced and a retracted position. The lever arm includes a gripping portion to permit a handhold for manual operation thereof. A pair of handle-engaging heads are movably coupled to the base. The base includes two sets of opposite flange portions, each set being positioned such that the opposite flange portions are disposed on opposite sides of the handle of one or the other circuit interrupters. The flanges each have an arcuate opening. The heads each comprise a pair of elongated pins spaced parallel apart. The pins have outer surface portions between opposite ends, and these outer surface portion define opposed abutment surfaces. The heads are positioned such that the handle of one or the other circuit interrupters is removably received between these abutment surfaces.

The lever arm turns an axle via a ratchet assembly that permits the axle to turn in one direction and opposes movement of the axle in the direction counter to said one direction. The axle turns a crank which likewise turns in a single direction only. A pair of connecting rods have proximal ends coupled to the crank and distal ends formed as a U-shaped yokes with opposite arms which respectively couple to the handle-engaging pins of one or the other heads. Thus, manual operation of the lever arm causes the crank to turn the proximal ends of the connecting rods in a circular path. The distal ends correspondingly drive the abutment surfaces against the handles to move the handle between the operative positions thereof.

The arcuate openings of the flange portions guide the abutment surfaces in an arcuate path such that the abutment surfaces are maintained in a substantially constant relative position on the handles as the handles move between the operative positions. Thus the abutment surfaces neither slide nor roll on the handles because there is no relative displacement therebetween. A particular arrangement involves pivoted handles. The arcuate openings guide the abutment surfaces in arcuate paths about an axis that is coincident with the pivot axis defined by the handle of the associated circuit interrupter.

The base is formed to clap together with the generally planar surfaces of the circuit components. These planar surfaces characteristically have a boss from which the handle protrudes. The base includes an opening for passing the boss therethrough until the base claps together with the generally planar surface. The base preferably has a planar mating surface.

Each connecting rod is arranged to advance and retract in a plane of symmetry through the handle of the associated circuit component. This plane of symmetry perpendicularly intersects the pivot axis defined by the pivoted handle. A symmetrically arranged connecting rod eliminates the problem of twist between the handle and the handle-engaging pins.

A number of additional features and objects will also become apparent in connection with the following discussion of preferred embodiments and examples.

BRIEF DESCRIPTION OF THE DRAWINGS

There are shown in the drawings certain exemplary embodiments of the invention as presently preferred. It should be understood that the invention is not limited to the embodiments disclosed as examples, and is capable of variation within the scope of the appended claims. In the drawings,

FIG. 1 is a perspective view of a typical transfer switch a