CA3107483A1 - Spring loaded ground clamp - Google Patents
Spring loaded ground clamp Download PDFInfo
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- CA3107483A1 CA3107483A1 CA3107483A CA3107483A CA3107483A1 CA 3107483 A1 CA3107483 A1 CA 3107483A1 CA 3107483 A CA3107483 A CA 3107483A CA 3107483 A CA3107483 A CA 3107483A CA 3107483 A1 CA3107483 A1 CA 3107483A1
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- hot stick
- lever arm
- spring
- jaw
- jaws
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- 239000004020 conductor Substances 0.000 claims description 24
- 210000005069 ears Anatomy 0.000 claims description 4
- 230000006835 compression Effects 0.000 description 6
- 238000007906 compression Methods 0.000 description 6
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 206010014405 Electrocution Diseases 0.000 description 2
- 239000011152 fibreglass Substances 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G1/00—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines
- H02G1/02—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines for overhead lines or cables
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
- H01R4/66—Connections with the terrestrial mass, e.g. earth plate, earth pin
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- Electric Cable Installation (AREA)
Abstract
A spring loaded grounding clamp system uses a strong linear spring force spring driving a piston mounted movable jaw as a safety lockout. The system includes a ground clamp which, when connected to and seated on, the end of a hot stick tool, provides for electrically insulated remote operation of the spring loaded ground clamp by a lineman holding the hot stick tool and pulling on, or releasing, a lever arm on the hot stick tool. The system provides increased safety for the lineman as the spring providing the spring loading of the clamp has a high spring force to overcome, thus providing the lockout. The lever arm on the hot stick tool provides mechanical advantage in order to overcome the spring force and thus release the lockout, and cannot usefully operate the spring loaded ground clamp manually without the hot stick tool.
Description
SPRING LOADED GROUND CLAMP
Technical Field This invention relates to the field of clamping devices that removably clamp a ground cable onto an electrical conductor, and in particular to a ground clamp that releasably clamps onto an electrical conductor using only a fixed jaw and a high compression spring-loaded movable jaw, wherein the spring loaded jaw cannot be manually retracted away from the fixed jaw without the use of a customized hot stick, made to provide a lineman with a significant mechanical advantage so as to be able to retract the movable jaw from the fixed jaw.
Background Electrical workers use grounding cables regularly in the industry to handle dangerous voltage and current hazard on de-energized power lines and electrical equipment. Grounds are designed to be installed and removed using a long insulating tool, referred to herein as a hot stick, to keep the worker at a safe distance from the hazard.
When installing grounds, the first connection is always made to a ground or earth point. Workers will normally make this connection by hand instead of with the insulated hot stick, as there is no hazardous energy when making this connection.
Any time a connection is made to an electrical conductor or apparatus that could be at a different electrical potential from ground, this connection must be made using an insulating tool. This is especially true in a high voltage environment (for example, over 69 kV). Due to the design of conventional ground clamps, they can Date Recue/Date Received 2021-01-29 be installed and removed by hand instead of being installed using an insulating tool. It is not uncommon in applicant's experience for workers to make the mistake of installing a ground clamp on a conductor, or removing one from a conductor by hand instead of with an insulating tool. This potentially exposes the worker to a voltage and current potential and consequently may result in electrocution of the worker. To applicant's knowledge, this has accounted for fatalities and electrocution incidents in the industry.
Consequently, there is a need in the industry for a ground clamp that operates in combination with an insulating tool so as to prevent the worker or lineman from 3.0 being able to operate the ground clamp without the use of the insulating tool.
This is to inhibit workers or linemen from attempting to install or remove the ground clamp by hand. To accomplish this a lock out mechanism in the form of a strong spring having a large spring force is described below which prevents manual operation of the ground clamp as the ground clamp can only be actuated or un-locked with the customised insulating tool.
Summary A grounding clamp system according to the present disclosure includes a first jaw and a second jaw in opposed facing relation to the first jaw so as to define a gap therebetween. The first jaw is a piston mounted movable jaw. The piston is slidably mounted in a housing. A first end of the piston is mounted to the first movable jaw. The housing is coupled to the second fixed jaw by a rigid frame so as to maintain the first and second jaws in their opposed facing relation. A
spring is mounted in the housing and is coupled to the piston to resiliently urge the piston and the first jaw towards the second jaw so as to resiliently close the gap Date Recue/Date Received 2021-01-29 between the first and second jaws. The spring has a spring force in the range of 150 to 250 pounds force required to fully compress the spring.
A hot stick connector, such as an eye mounted to the second end of the piston, extends from the second end of the piston. The second end of the piston is opposite the first end of the piston.
The system includes an insulated hot stick having a hook retractably mounted in a first end thereof. A tensioning rod linkage is coupled to the hook at one end of the rod linkage, and coupled at the other end of the tensioning rod linkage to a lever arm. The lever arm is pivotally mounted on the hot stick, on handle end of the hot stick. The handle end of the hot stick is opposite the first end of the hot stick. The other end of the tensioning rod linkage is mounted to the lever arm at a mechanical advantage distance along the lever arm away from the hot stick.
The first end of the hot stick is adapted to have the housing seat thereon when the hook is engaged with the hot stick connector eye and the hook retracted to a first retracted position by rotation of the lever arm in a first direction so as to tension the tensioning rod linkage. In the first retracted position the hook pulls on the connector to seat the ground clamp housing onto the first end of the hot stick. Continued and increasing tension on the tensioning rod linkage by further rotation of the lever arm in the first direction away from the first end of the hot stick and towards the second end of the hot stick retracts the hook to a second retracted position wherein the piston, for example a flange on the piston, compresses the spring against the return biasing spring force of the spring so as to retract the first jaw away from the second jaw to thereby open the gap so as to allow entry or exit of a conductor into the gap between the jaws.
Date Recue/Date Received 2021-01-29 When the lever arm is rotated in a second direction opposite to the first direction, the return biasing spring force of the spring urges the first jaw towards the second jaw to thereby at least partly close the gap. This engages the jaws with a conductor positioned in the gap. The heavy or strong spring force keeps the ground clamp jaws tightly clamped on the conductor.
The lever arm is rotated in the first direction to open the gap between the first and second jaws. The lever arm rotated in the second direction to at least partly close the gap so as to clamp a conductor between the first and second jaws.
Advantageously the tensioning rod linkage is pivotally mounted to the lever arm.
3.0 Further advantageously the tensioning rod linkage includes first and second linear rods, wherein the first linear rod is coupled at a first end thereof to the hook and is slidably mounted to the first end of the hot stick so as to translate linearly along and parallel to the first end of the hot stick, and wherein the first linear rod is pivotally coupled at a second end thereof, opposite the first end of the first linear rod, to a first end of the second linear rod. The second end of the second linear rod, being pivotally mounted to the lever arm, is pivotable relative to the first linear rod so as to form a small included angle between the second linear rod and the hot stick as the lever arm is rotated to open and close the first and second jaws.
Yet further advantageously, the lever arm is an over-center lever arm releasably lockable into an over-center position when fully rotated in the first direction until a handle end of the lever arm is flush against the handle end of the hot stick.
Date Recue/Date Received 2021-01-29 Brief Description of the Drawings FIG. 1 is a side elevation view of a ground clamp according to the present specification.
FIG. 2 is a section view along line 2-2 in FIG. 1.
.. FIG. 3 is, in perspective view, the ground clamp of FIG. 1 mounted on the end of a customised hot stick with a ground clamp tensioning assembly according to the present specification, with the jaws of the clamp open.
FIG. 4 is the spring loaded ground clamp system of FIG. 3 in front elevation view.
FIG. 5 is the spring loaded ground clamp system of FIG. 4 in side elevation view.
3.0 FIG. 6 is the spring loaded ground clamp system of FIG. 5, with the jaws of the clamp closed.
FIG. 7 is a section view along line 7-7 showing the ground clamp in its open position with spring completely compressed in FIG. 5.
FIG. 8 is the section view of FIG. 7 showing the jaws of the clamp closed with the .. spring uncompressed, and showing an alternative embodiment of the hook and hook shank wherein the hook is pivotally mounted on the shank.
FIG. 9 is, in partially cutaway view, the ground clamp of FIG. 1 with the clamp jaws clamping a conductor having a maximum diameter that can be accommodated in the illustrated embodiment.
Date Recue/Date Received 2021-01-29 FIG. 10 is the view of FIG. 9 with the clamp jaws partly closed so as to clamp a slightly smaller diameter conductor.
FIG. 11 is the view of FIG. 10 with the clamp jaws closed to accommodate a small diameter conductor.
FIG. 12 is, in perspective view, the hot stick of the system shown in FIG. 3.
FIG. 13 is, in side elevation view, the hot stick and tensioning assembly of FIG. 12, with the hot stick head removed.
FIG. 14 is the view of FIG. 13 showing the tensioning assembly on the hot stick in its partly tensioned position with the hot stick head removed.
FIG. 15 is an enlarged perspective view of the lever arm and tensioning rod linkage of the tensioning assembly in its partly tensioned position.
Detailed Description As seen in the accompanying illustrations wherein like part numbers represent corresponding parts in each view, the present disclosure is a spring loaded grounding clamp system which employs a strong spring as a safety lockout for the ground clamp.
The system includes a ground clamp 12 which, when connected to and seated on, the hook end of a hot stick 14, provides for electrically insulated remote operation of a spring loaded ground clamp by a lineman holding the hot stick and pulling on, or releasing, a lever arm on the hot stick. The system provides increased safety for the lineman as the heavy, in the sense of having a strong Date Recue/Date Received 2021-01-29 spring force, spring providing the spring loading of the clamp has a high spring force to overcome; the object being that the lineman is forced to use the hot stick tool in order to overcome the spring's spring force and cannot usefully operate the spring loaded ground clamp manually without the hot stick tool.
Thus as seen in FIGS. 1 and 2, ground clamp 12 includes a first movable jaw 16 and a second fixed jaw 18. The first and second jaws 16 and 18 are in opposed facing relation so as to define a conductor-receiving gap 20 therebetween.
Spring housing 22 contains a piston 24 slidably journaled therethrough for translation of the piston in direction A. An upper end 24a of piston 24 is mounted to the 3.0 underside of the first jaw 16 so as to also translate first jaw 16 in direction A.
Spring housing 22 is coupled to the second jaw 18 by a rigid frame 26 so as to maintain the first and second jaws in their opposed facing relation oppositely disposed about gap 20.
Spring 28 is mounted in the spring housing 22. Flange 30 is mounted to piston within housing 22 so as to couple piston 24 onto spring 28. Spring 28 presses against flange 30 so as to resiliently urge piston 24 and first jaw 16 towards the second jaw 18. Translation of first jaw 16 towards second jaw 18 at least partially closes the gap 20 so as to clamp a conductor 32 between the jaws thereby forming an electrical connection between the ground clamp and the conductor.
Advantageously spring 28 is a helical coil spring having a strong, preferably linear, spring force, for example in the range of 150 to 250 pounds force required to fully compress the spring.
Date Recue/Date Received 2021-01-29 The spring force is selected so as to balance two competing human factors. To applicant's knowledge a lineman, using both of his hands, would be hard pressed to continuously pull a tension force between his hands of no more than approximately 150 pounds force.
Keeping in mind that, in the present application, if a lineman was capable of that pulling force, it would in applicant's view still be very difficult for the lineman to translate that strength into compressing the spring 28 in the ground clamp so as to open the clamp's jaws and 18, and then operating the ground clamp described herein in which the spring 28 has a spring force in full compression of at least 150 pounds force, 3.0 without the assistance of the hot stick 14 also described herein.
Without the use of the hot stick 14, the lineman would have to hold the ground clamp 12 in one hand, for example by grasping the ground clamp frame 26 which holds the two jaws in their alignment and hold the ground clamp-to-hot stick connector (for example the eye 34 extending from the lower end 24b of the piston 24 in the illustrated examples) in the other hand, and while pulling the two apart manually so as to open the jaws. Then, without releasing the tension, the lineman would have to reach out, for example from the bucket truck in which the lineman is standing and hook the open jaws of the ground clamp 12 over the conductor 32.
Applicant is of the view that the lineman would if given the choice take the easier (and also safer) route and use the hot stick 14 with the tensioning assembly described herein.
Another human factor that applicant has taken into consideration in the design of the present ground clamp system, is the force that a lineman can exert on the lever arm 36 mounted on hot stick 14 when compressing the spring 28 in the .. ground clamp 12. Given the mechanical advantage provided by the lever arm 36, Date Recue/Date Received 2021-01-29 a lineman must still be able to fully compress the spring in the ground clamp using the tensioning assembly on the hot stick, which may become difficult where the spring has a very high spring force at full compression. Hence there will be an upper limit on the spring strength of the spring, above which a lineman may struggle to operate the tensioning assembly.
There will also be an upper limit on the spring strength of the spring, above which the lever arm 36 and tensioning rod linkage 38 may not withstand after repeated operation of the tensioning assembly, without the lever arm and linkage having to be heavy in order to be sufficiently strong. If the lever arm and tensioning linkage 3.0 are overly rugged and heavy, the hot stick may become cumbersome. In applicant's opinion, a heavy and cumbersome hot stick is less likely to be used by a lineman than one that is relatively light and thus more easily used. The design factor to be considered then becomes whether a relatively lightweight lever arm 36 and associated tensioning rod linkage 38 will withstand the repeated force necessary to repeatedly fully compress the spring 28 in the ground clamp 12 when fully opening the clamp's jaws 16 and 18. In the illustrated example in FIGS.
3-7, it takes approximately 160 pounds force to fully compress spring 28.
The lever arm 36 provides a mechanical advantage to the lineman. This allows the lineman to pull the required compression force on the ground clamp spring 28 via the lever arm 36 and tensioning rod linkage 38 to open the jaws 16 and 18 while using only one hand to pull on the lever arm 36 all the way to the locked over center position, and then manipulating the hot stick 14 with the both hands.
As seen by way of example in the illustrations, for example FIGS. 6, and 12-14, the mechanical advantage may in one embodiment be in the range of approximately Date Recue/Date Received 2021-01-29 3:1 to 4:1. The approximate range of mechanical advantage may be seen by comparing in the figures the distance D1 (shown in FIG. 6) between the lever arm hinge 40 (where the lever arm 36 is pivotally mounted to hot stick 14), and the handle end 36a of lever arm 36, to the distance D2 between the lever arm hinge 40 and the pivoting connection (pinned hinge 42) where the rod linkage 38 is joined to lever arm 36 by an adjustable threaded connection between 38a and 46.
Distance D2 is alternatively referred to herein as the mechanical advantage distance of the lever arm.
Thus, by way of example, if the required compression force to fully compress 3.0 spring 28 is 160 pounds force, then, using lever arm 36, the lineman would have to pull in direction B on lever arm handle end 36a using approximately 40 pounds force if the mechanical advantage is approximately 4:1.
Using the same mechanical advantage ratio of 4:1, if the spring force of spring 28 at full compression is 240 pounds force, then the lineman would have to pull on lever arm 36 with 60 pounds force. If the mechanical advantage ratio is only 3:1, then in the latter example, the lineman would have to pull on the lever arm with 80 pounds force, which in applicant's opinion is likely the upper limit, and possibly more than the upper limit, of what a lineman may possibly be able to achieve.
Advantageously, as illustrated, lever arm 36 may be mounted on hot stick 14 using a collar or sleeve 44, wherein the lever arm hinge 40 is mounted onto sleeve 44, for example midway along its length. The length of sleeve 44 assists in distributing the load on hinge 40 to hot stick 14 during rotation of the lever arm in direction C in order to open the ground clamp's jaws 16 and 18. Lever arm hinge 40 is elevated off sleeve 44 by a small distance, sufficient to provide for over-Date Recue/Date Received 2021-01-29 center locking of lever arm 36 against hot stick 14 once lever arm 36 has been fully rotated in direction C. The length of rod linkage 38 is adjustable so that spring 28 is fully compressed as lever arm 36 comes to it's fully rotated over center and locked position parallel to hot stick 14 upon completion of full rotation in direction C. Preferably, as lever arm 36 is rotating about hinge 40 into it's over-center position flush along hot stick 14, a small force component from the tension on the tensioning rod linkage 38 urges lever arm 36 against hot stick 14. This retention force may for example be in the order of five pounds force. Thus, in that example, the lineman would have only to exert five pounds force pulling 3.0 lever arm 36 away from hot stick 14 in order to release lever arm 36 from its over-center locked position closing the ground clamp.
As seen in FIG. 15, in the illustrated embodiment, not intended to be limiting, lever arm hinge 40 is mounted to, so as to be raised off, sleeve 44, on a pair of parallel mounting ears 43. Parallel fork arms 36b on lever arm 36 extend from the handle end 36a to lever arm hinge 40, where the ends of fork arms 36b are pinned to their corresponding mounting ears 43 for rotation of lever arm 36 in direction C so as to rotate lever arm 36 relative to sleeve 44 and hot stick 14.
Tensioning rod linkage 38 includes a planar threaded member 38a rotationally coupled at one end to pinned hinge 42 on fork arms 36b, and at the other end to a length adjustment coupling member 46. Length adjustment coupling member 46 may be mounted in threaded engagement to planar member 38a, or may be threaded at both female ends of member 46 in the manner of a turnbuckle, so as to allow selective lengthening or shortening of tensioning rod linkage 38. As lever arm 36 is rotated in direction C into its over-center locking position flush along hot stick 14, planar member 38a is nested between fork arms 36b and mounting Date Recue/Date Received 2021-01-29 ears 43 so as to allow tensioning rod linkage 38 to also lie flush along hot stick 14.
When lever arm is unlocked from it's over-center locked position by being rotated in a direction opposite to direction C, a small pulling force is required, for example approximately five pounds force, to provide the moment required to break open the over-center locking. As the rotation of lever arm 36 then continues, tensioning rod linkage moves in direction D thereby releasing the tension holding spring 28 compressed closing ground clamp. Spring 28 then urges piston 24 and first jaw 16 towards second jaw 18, at least partly closing gap 20, and clamping a conductor 32 located in the gap between the jaws 16 and 18 with the return 3.0 spring force of spring 28. Preferably, spring 28 is substantially linear so that spring force is almost the same through all or substantially all of its full range of motion, that is from uncompressed to fully compressed.
Tensioning rod linkage 38 further includes at least a long, primary linkage member, or tie rod 38b, which may be an electrically insulated flexible rod such as made of fiberglass so as to be relatively light weight yet strong in tension.
The length of tie rod 38b will depend on the length of hot stick 14. The longer the hot stick, the longer tie rod 38b. In the illustrated embodiment, tie rod 38b extends from coupling member 46 to a hook rod 48. Tie rod 38b is pivotally coupled to hook rod 48 by pinned hinge 52. Pinned hinge 52 allows rotation of tie rod 38b in direction E relative to hook rod 48. Hook rod 48 is slidably mounted in a longitudinally extending channel 50a in hot stick head 50 for translation of hook rod 48 along the hook end 14a of hot stick 14, parallel and snugly adjacent to hook end 14a of hot stick 14. The channel 50a in head 50 maintains hook rod 48 parallel to hot stick 14 during it's translation along the hook end 14a.
Date Recue/Date Received 2021-01-29 Tie rod 38b does not however remain parallel to hot stick 14 as lever arm 36 is rotated. As lever arm 36 is rotated about lever arm hinge 40, pinned hinge 42 is correspondingly rotated through an arc about hinge 40. Because tie rod 38b is coupled to pinned hinge 42 via members 38a and 46, rotation of pinned hinge 42 in an arc swings tie rod 38b in direction E about pinned hinge 52, and correspondingly through a small included angle F formed between tie rod 38b and hot stick 14. The shorter the length of hot stick 14, the slightly greater the included angle F, and conversely the longer the length of hot stick 14, the slightly smaller the included angle F.
A hook 54 is mounted onto the end of hook rod 48 opposite to pinned hinge 52.
The shank 54a of hook 54 is rigidly co-linear with hook rod 48, and is free to slide along the channel 50a in head 50 in which hook rod 48 is slidably mounted.
Thus hook 54 is retractably mounted on the hook end 14a of hot stick 14. As tensioning rod linkage 38 is thus coupled to hook 54, rotation of lever arm 36 in direction C
retracts hook 54 to or into the distal end 50b of head 50 on hot stick 14.
The hook end 14a of hot stick 14, and in particular head 50 is adapted to have spring housing 22 seat onto the end of head 50 when 54 hook is engaged with eye 34 and the hook retracted to a first retracted position by rotation of the lever arm in direction C so as to tension the tensioning rod linkage. A hollow guard having a bulbous cavity may optionally be mounted to the underside of the spring housing 22 so as to cover eye 34 while allowing insertion of hook 54 and the end of head 50 into the guard cavity so that a lineman may engage hook 54 with eye 34 inside the guard. The guard is intended to inhibit a lineman from attempting to use a shortcut to overcome spring 28 such as by inserting a hand held lever or handle Date Recue/Date Received 2021-01-29 device, for example a screwdriver, through eye 34 so as to provide the lineman with greater purchase to pull down on piston 24 with increased force.
In the first retracted position the hook 54 pulls on the eye 34 to seat the spring housing 22 onto head 50 at the first end of the hot stick. Continued and increasing tension on the tensioning rod linkage 38 by further rotation of lever arm 36 in direction C (away from the first end of the hot stick and towards the second, opposite, end of the hot stick) retracts the hook 54 to a second retracted position wherein the flange 30 on piston 24 compresses the spring 28 against it's return biasing spring force so as to retract the first jaw 16 away from the second 3.0 jaw 18 to thereby open the gap 20 so as to accept a conductor 32 therein.
Date Recue/Date Received 2021-01-29
Technical Field This invention relates to the field of clamping devices that removably clamp a ground cable onto an electrical conductor, and in particular to a ground clamp that releasably clamps onto an electrical conductor using only a fixed jaw and a high compression spring-loaded movable jaw, wherein the spring loaded jaw cannot be manually retracted away from the fixed jaw without the use of a customized hot stick, made to provide a lineman with a significant mechanical advantage so as to be able to retract the movable jaw from the fixed jaw.
Background Electrical workers use grounding cables regularly in the industry to handle dangerous voltage and current hazard on de-energized power lines and electrical equipment. Grounds are designed to be installed and removed using a long insulating tool, referred to herein as a hot stick, to keep the worker at a safe distance from the hazard.
When installing grounds, the first connection is always made to a ground or earth point. Workers will normally make this connection by hand instead of with the insulated hot stick, as there is no hazardous energy when making this connection.
Any time a connection is made to an electrical conductor or apparatus that could be at a different electrical potential from ground, this connection must be made using an insulating tool. This is especially true in a high voltage environment (for example, over 69 kV). Due to the design of conventional ground clamps, they can Date Recue/Date Received 2021-01-29 be installed and removed by hand instead of being installed using an insulating tool. It is not uncommon in applicant's experience for workers to make the mistake of installing a ground clamp on a conductor, or removing one from a conductor by hand instead of with an insulating tool. This potentially exposes the worker to a voltage and current potential and consequently may result in electrocution of the worker. To applicant's knowledge, this has accounted for fatalities and electrocution incidents in the industry.
Consequently, there is a need in the industry for a ground clamp that operates in combination with an insulating tool so as to prevent the worker or lineman from 3.0 being able to operate the ground clamp without the use of the insulating tool.
This is to inhibit workers or linemen from attempting to install or remove the ground clamp by hand. To accomplish this a lock out mechanism in the form of a strong spring having a large spring force is described below which prevents manual operation of the ground clamp as the ground clamp can only be actuated or un-locked with the customised insulating tool.
Summary A grounding clamp system according to the present disclosure includes a first jaw and a second jaw in opposed facing relation to the first jaw so as to define a gap therebetween. The first jaw is a piston mounted movable jaw. The piston is slidably mounted in a housing. A first end of the piston is mounted to the first movable jaw. The housing is coupled to the second fixed jaw by a rigid frame so as to maintain the first and second jaws in their opposed facing relation. A
spring is mounted in the housing and is coupled to the piston to resiliently urge the piston and the first jaw towards the second jaw so as to resiliently close the gap Date Recue/Date Received 2021-01-29 between the first and second jaws. The spring has a spring force in the range of 150 to 250 pounds force required to fully compress the spring.
A hot stick connector, such as an eye mounted to the second end of the piston, extends from the second end of the piston. The second end of the piston is opposite the first end of the piston.
The system includes an insulated hot stick having a hook retractably mounted in a first end thereof. A tensioning rod linkage is coupled to the hook at one end of the rod linkage, and coupled at the other end of the tensioning rod linkage to a lever arm. The lever arm is pivotally mounted on the hot stick, on handle end of the hot stick. The handle end of the hot stick is opposite the first end of the hot stick. The other end of the tensioning rod linkage is mounted to the lever arm at a mechanical advantage distance along the lever arm away from the hot stick.
The first end of the hot stick is adapted to have the housing seat thereon when the hook is engaged with the hot stick connector eye and the hook retracted to a first retracted position by rotation of the lever arm in a first direction so as to tension the tensioning rod linkage. In the first retracted position the hook pulls on the connector to seat the ground clamp housing onto the first end of the hot stick. Continued and increasing tension on the tensioning rod linkage by further rotation of the lever arm in the first direction away from the first end of the hot stick and towards the second end of the hot stick retracts the hook to a second retracted position wherein the piston, for example a flange on the piston, compresses the spring against the return biasing spring force of the spring so as to retract the first jaw away from the second jaw to thereby open the gap so as to allow entry or exit of a conductor into the gap between the jaws.
Date Recue/Date Received 2021-01-29 When the lever arm is rotated in a second direction opposite to the first direction, the return biasing spring force of the spring urges the first jaw towards the second jaw to thereby at least partly close the gap. This engages the jaws with a conductor positioned in the gap. The heavy or strong spring force keeps the ground clamp jaws tightly clamped on the conductor.
The lever arm is rotated in the first direction to open the gap between the first and second jaws. The lever arm rotated in the second direction to at least partly close the gap so as to clamp a conductor between the first and second jaws.
Advantageously the tensioning rod linkage is pivotally mounted to the lever arm.
3.0 Further advantageously the tensioning rod linkage includes first and second linear rods, wherein the first linear rod is coupled at a first end thereof to the hook and is slidably mounted to the first end of the hot stick so as to translate linearly along and parallel to the first end of the hot stick, and wherein the first linear rod is pivotally coupled at a second end thereof, opposite the first end of the first linear rod, to a first end of the second linear rod. The second end of the second linear rod, being pivotally mounted to the lever arm, is pivotable relative to the first linear rod so as to form a small included angle between the second linear rod and the hot stick as the lever arm is rotated to open and close the first and second jaws.
Yet further advantageously, the lever arm is an over-center lever arm releasably lockable into an over-center position when fully rotated in the first direction until a handle end of the lever arm is flush against the handle end of the hot stick.
Date Recue/Date Received 2021-01-29 Brief Description of the Drawings FIG. 1 is a side elevation view of a ground clamp according to the present specification.
FIG. 2 is a section view along line 2-2 in FIG. 1.
.. FIG. 3 is, in perspective view, the ground clamp of FIG. 1 mounted on the end of a customised hot stick with a ground clamp tensioning assembly according to the present specification, with the jaws of the clamp open.
FIG. 4 is the spring loaded ground clamp system of FIG. 3 in front elevation view.
FIG. 5 is the spring loaded ground clamp system of FIG. 4 in side elevation view.
3.0 FIG. 6 is the spring loaded ground clamp system of FIG. 5, with the jaws of the clamp closed.
FIG. 7 is a section view along line 7-7 showing the ground clamp in its open position with spring completely compressed in FIG. 5.
FIG. 8 is the section view of FIG. 7 showing the jaws of the clamp closed with the .. spring uncompressed, and showing an alternative embodiment of the hook and hook shank wherein the hook is pivotally mounted on the shank.
FIG. 9 is, in partially cutaway view, the ground clamp of FIG. 1 with the clamp jaws clamping a conductor having a maximum diameter that can be accommodated in the illustrated embodiment.
Date Recue/Date Received 2021-01-29 FIG. 10 is the view of FIG. 9 with the clamp jaws partly closed so as to clamp a slightly smaller diameter conductor.
FIG. 11 is the view of FIG. 10 with the clamp jaws closed to accommodate a small diameter conductor.
FIG. 12 is, in perspective view, the hot stick of the system shown in FIG. 3.
FIG. 13 is, in side elevation view, the hot stick and tensioning assembly of FIG. 12, with the hot stick head removed.
FIG. 14 is the view of FIG. 13 showing the tensioning assembly on the hot stick in its partly tensioned position with the hot stick head removed.
FIG. 15 is an enlarged perspective view of the lever arm and tensioning rod linkage of the tensioning assembly in its partly tensioned position.
Detailed Description As seen in the accompanying illustrations wherein like part numbers represent corresponding parts in each view, the present disclosure is a spring loaded grounding clamp system which employs a strong spring as a safety lockout for the ground clamp.
The system includes a ground clamp 12 which, when connected to and seated on, the hook end of a hot stick 14, provides for electrically insulated remote operation of a spring loaded ground clamp by a lineman holding the hot stick and pulling on, or releasing, a lever arm on the hot stick. The system provides increased safety for the lineman as the heavy, in the sense of having a strong Date Recue/Date Received 2021-01-29 spring force, spring providing the spring loading of the clamp has a high spring force to overcome; the object being that the lineman is forced to use the hot stick tool in order to overcome the spring's spring force and cannot usefully operate the spring loaded ground clamp manually without the hot stick tool.
Thus as seen in FIGS. 1 and 2, ground clamp 12 includes a first movable jaw 16 and a second fixed jaw 18. The first and second jaws 16 and 18 are in opposed facing relation so as to define a conductor-receiving gap 20 therebetween.
Spring housing 22 contains a piston 24 slidably journaled therethrough for translation of the piston in direction A. An upper end 24a of piston 24 is mounted to the 3.0 underside of the first jaw 16 so as to also translate first jaw 16 in direction A.
Spring housing 22 is coupled to the second jaw 18 by a rigid frame 26 so as to maintain the first and second jaws in their opposed facing relation oppositely disposed about gap 20.
Spring 28 is mounted in the spring housing 22. Flange 30 is mounted to piston within housing 22 so as to couple piston 24 onto spring 28. Spring 28 presses against flange 30 so as to resiliently urge piston 24 and first jaw 16 towards the second jaw 18. Translation of first jaw 16 towards second jaw 18 at least partially closes the gap 20 so as to clamp a conductor 32 between the jaws thereby forming an electrical connection between the ground clamp and the conductor.
Advantageously spring 28 is a helical coil spring having a strong, preferably linear, spring force, for example in the range of 150 to 250 pounds force required to fully compress the spring.
Date Recue/Date Received 2021-01-29 The spring force is selected so as to balance two competing human factors. To applicant's knowledge a lineman, using both of his hands, would be hard pressed to continuously pull a tension force between his hands of no more than approximately 150 pounds force.
Keeping in mind that, in the present application, if a lineman was capable of that pulling force, it would in applicant's view still be very difficult for the lineman to translate that strength into compressing the spring 28 in the ground clamp so as to open the clamp's jaws and 18, and then operating the ground clamp described herein in which the spring 28 has a spring force in full compression of at least 150 pounds force, 3.0 without the assistance of the hot stick 14 also described herein.
Without the use of the hot stick 14, the lineman would have to hold the ground clamp 12 in one hand, for example by grasping the ground clamp frame 26 which holds the two jaws in their alignment and hold the ground clamp-to-hot stick connector (for example the eye 34 extending from the lower end 24b of the piston 24 in the illustrated examples) in the other hand, and while pulling the two apart manually so as to open the jaws. Then, without releasing the tension, the lineman would have to reach out, for example from the bucket truck in which the lineman is standing and hook the open jaws of the ground clamp 12 over the conductor 32.
Applicant is of the view that the lineman would if given the choice take the easier (and also safer) route and use the hot stick 14 with the tensioning assembly described herein.
Another human factor that applicant has taken into consideration in the design of the present ground clamp system, is the force that a lineman can exert on the lever arm 36 mounted on hot stick 14 when compressing the spring 28 in the .. ground clamp 12. Given the mechanical advantage provided by the lever arm 36, Date Recue/Date Received 2021-01-29 a lineman must still be able to fully compress the spring in the ground clamp using the tensioning assembly on the hot stick, which may become difficult where the spring has a very high spring force at full compression. Hence there will be an upper limit on the spring strength of the spring, above which a lineman may struggle to operate the tensioning assembly.
There will also be an upper limit on the spring strength of the spring, above which the lever arm 36 and tensioning rod linkage 38 may not withstand after repeated operation of the tensioning assembly, without the lever arm and linkage having to be heavy in order to be sufficiently strong. If the lever arm and tensioning linkage 3.0 are overly rugged and heavy, the hot stick may become cumbersome. In applicant's opinion, a heavy and cumbersome hot stick is less likely to be used by a lineman than one that is relatively light and thus more easily used. The design factor to be considered then becomes whether a relatively lightweight lever arm 36 and associated tensioning rod linkage 38 will withstand the repeated force necessary to repeatedly fully compress the spring 28 in the ground clamp 12 when fully opening the clamp's jaws 16 and 18. In the illustrated example in FIGS.
3-7, it takes approximately 160 pounds force to fully compress spring 28.
The lever arm 36 provides a mechanical advantage to the lineman. This allows the lineman to pull the required compression force on the ground clamp spring 28 via the lever arm 36 and tensioning rod linkage 38 to open the jaws 16 and 18 while using only one hand to pull on the lever arm 36 all the way to the locked over center position, and then manipulating the hot stick 14 with the both hands.
As seen by way of example in the illustrations, for example FIGS. 6, and 12-14, the mechanical advantage may in one embodiment be in the range of approximately Date Recue/Date Received 2021-01-29 3:1 to 4:1. The approximate range of mechanical advantage may be seen by comparing in the figures the distance D1 (shown in FIG. 6) between the lever arm hinge 40 (where the lever arm 36 is pivotally mounted to hot stick 14), and the handle end 36a of lever arm 36, to the distance D2 between the lever arm hinge 40 and the pivoting connection (pinned hinge 42) where the rod linkage 38 is joined to lever arm 36 by an adjustable threaded connection between 38a and 46.
Distance D2 is alternatively referred to herein as the mechanical advantage distance of the lever arm.
Thus, by way of example, if the required compression force to fully compress 3.0 spring 28 is 160 pounds force, then, using lever arm 36, the lineman would have to pull in direction B on lever arm handle end 36a using approximately 40 pounds force if the mechanical advantage is approximately 4:1.
Using the same mechanical advantage ratio of 4:1, if the spring force of spring 28 at full compression is 240 pounds force, then the lineman would have to pull on lever arm 36 with 60 pounds force. If the mechanical advantage ratio is only 3:1, then in the latter example, the lineman would have to pull on the lever arm with 80 pounds force, which in applicant's opinion is likely the upper limit, and possibly more than the upper limit, of what a lineman may possibly be able to achieve.
Advantageously, as illustrated, lever arm 36 may be mounted on hot stick 14 using a collar or sleeve 44, wherein the lever arm hinge 40 is mounted onto sleeve 44, for example midway along its length. The length of sleeve 44 assists in distributing the load on hinge 40 to hot stick 14 during rotation of the lever arm in direction C in order to open the ground clamp's jaws 16 and 18. Lever arm hinge 40 is elevated off sleeve 44 by a small distance, sufficient to provide for over-Date Recue/Date Received 2021-01-29 center locking of lever arm 36 against hot stick 14 once lever arm 36 has been fully rotated in direction C. The length of rod linkage 38 is adjustable so that spring 28 is fully compressed as lever arm 36 comes to it's fully rotated over center and locked position parallel to hot stick 14 upon completion of full rotation in direction C. Preferably, as lever arm 36 is rotating about hinge 40 into it's over-center position flush along hot stick 14, a small force component from the tension on the tensioning rod linkage 38 urges lever arm 36 against hot stick 14. This retention force may for example be in the order of five pounds force. Thus, in that example, the lineman would have only to exert five pounds force pulling 3.0 lever arm 36 away from hot stick 14 in order to release lever arm 36 from its over-center locked position closing the ground clamp.
As seen in FIG. 15, in the illustrated embodiment, not intended to be limiting, lever arm hinge 40 is mounted to, so as to be raised off, sleeve 44, on a pair of parallel mounting ears 43. Parallel fork arms 36b on lever arm 36 extend from the handle end 36a to lever arm hinge 40, where the ends of fork arms 36b are pinned to their corresponding mounting ears 43 for rotation of lever arm 36 in direction C so as to rotate lever arm 36 relative to sleeve 44 and hot stick 14.
Tensioning rod linkage 38 includes a planar threaded member 38a rotationally coupled at one end to pinned hinge 42 on fork arms 36b, and at the other end to a length adjustment coupling member 46. Length adjustment coupling member 46 may be mounted in threaded engagement to planar member 38a, or may be threaded at both female ends of member 46 in the manner of a turnbuckle, so as to allow selective lengthening or shortening of tensioning rod linkage 38. As lever arm 36 is rotated in direction C into its over-center locking position flush along hot stick 14, planar member 38a is nested between fork arms 36b and mounting Date Recue/Date Received 2021-01-29 ears 43 so as to allow tensioning rod linkage 38 to also lie flush along hot stick 14.
When lever arm is unlocked from it's over-center locked position by being rotated in a direction opposite to direction C, a small pulling force is required, for example approximately five pounds force, to provide the moment required to break open the over-center locking. As the rotation of lever arm 36 then continues, tensioning rod linkage moves in direction D thereby releasing the tension holding spring 28 compressed closing ground clamp. Spring 28 then urges piston 24 and first jaw 16 towards second jaw 18, at least partly closing gap 20, and clamping a conductor 32 located in the gap between the jaws 16 and 18 with the return 3.0 spring force of spring 28. Preferably, spring 28 is substantially linear so that spring force is almost the same through all or substantially all of its full range of motion, that is from uncompressed to fully compressed.
Tensioning rod linkage 38 further includes at least a long, primary linkage member, or tie rod 38b, which may be an electrically insulated flexible rod such as made of fiberglass so as to be relatively light weight yet strong in tension.
The length of tie rod 38b will depend on the length of hot stick 14. The longer the hot stick, the longer tie rod 38b. In the illustrated embodiment, tie rod 38b extends from coupling member 46 to a hook rod 48. Tie rod 38b is pivotally coupled to hook rod 48 by pinned hinge 52. Pinned hinge 52 allows rotation of tie rod 38b in direction E relative to hook rod 48. Hook rod 48 is slidably mounted in a longitudinally extending channel 50a in hot stick head 50 for translation of hook rod 48 along the hook end 14a of hot stick 14, parallel and snugly adjacent to hook end 14a of hot stick 14. The channel 50a in head 50 maintains hook rod 48 parallel to hot stick 14 during it's translation along the hook end 14a.
Date Recue/Date Received 2021-01-29 Tie rod 38b does not however remain parallel to hot stick 14 as lever arm 36 is rotated. As lever arm 36 is rotated about lever arm hinge 40, pinned hinge 42 is correspondingly rotated through an arc about hinge 40. Because tie rod 38b is coupled to pinned hinge 42 via members 38a and 46, rotation of pinned hinge 42 in an arc swings tie rod 38b in direction E about pinned hinge 52, and correspondingly through a small included angle F formed between tie rod 38b and hot stick 14. The shorter the length of hot stick 14, the slightly greater the included angle F, and conversely the longer the length of hot stick 14, the slightly smaller the included angle F.
A hook 54 is mounted onto the end of hook rod 48 opposite to pinned hinge 52.
The shank 54a of hook 54 is rigidly co-linear with hook rod 48, and is free to slide along the channel 50a in head 50 in which hook rod 48 is slidably mounted.
Thus hook 54 is retractably mounted on the hook end 14a of hot stick 14. As tensioning rod linkage 38 is thus coupled to hook 54, rotation of lever arm 36 in direction C
retracts hook 54 to or into the distal end 50b of head 50 on hot stick 14.
The hook end 14a of hot stick 14, and in particular head 50 is adapted to have spring housing 22 seat onto the end of head 50 when 54 hook is engaged with eye 34 and the hook retracted to a first retracted position by rotation of the lever arm in direction C so as to tension the tensioning rod linkage. A hollow guard having a bulbous cavity may optionally be mounted to the underside of the spring housing 22 so as to cover eye 34 while allowing insertion of hook 54 and the end of head 50 into the guard cavity so that a lineman may engage hook 54 with eye 34 inside the guard. The guard is intended to inhibit a lineman from attempting to use a shortcut to overcome spring 28 such as by inserting a hand held lever or handle Date Recue/Date Received 2021-01-29 device, for example a screwdriver, through eye 34 so as to provide the lineman with greater purchase to pull down on piston 24 with increased force.
In the first retracted position the hook 54 pulls on the eye 34 to seat the spring housing 22 onto head 50 at the first end of the hot stick. Continued and increasing tension on the tensioning rod linkage 38 by further rotation of lever arm 36 in direction C (away from the first end of the hot stick and towards the second, opposite, end of the hot stick) retracts the hook 54 to a second retracted position wherein the flange 30 on piston 24 compresses the spring 28 against it's return biasing spring force so as to retract the first jaw 16 away from the second 3.0 jaw 18 to thereby open the gap 20 so as to accept a conductor 32 therein.
Date Recue/Date Received 2021-01-29
Claims (15)
1. A grounding clamp system consisting of:
(a) a ground clamp head, including:
a first jaw, a second jaw in opposed facing relation to the first jaw so as to define a gap therebetween, a housing containing a piston slidably mounted therein, wherein a first end of the piston is mounted to the first jaw, and wherein the housing is coupled to the second jaw by a rigid frame so as to maintain the first and second jaws in their opposed facing relation, a heavy linear spring mounted in the housing and coupled to the piston to resiliently urge the piston and the first jaw towards the second jaw so as to resiliently close the gap between the first and second jaws, wherein the spring has a spring force in the range of 150 to 250 pounds force required to compress the spring, a hot stick connector extending from a second end of the piston opposite the first end of the piston, (b) a hot stick having a hook retractably mounted in a first end of the hot stick, a rod linkage coupled to the hook at one end of the rod linkage, and coupled at the other end of the rod linkage to a lever arm, wherein the lever arm is pivotally mounted on the hot stick, at one Date Recue/Date Received 2021-01-29 end of the lever arm, towards a second end of the hot stick opposite the first end of the hot stick, and wherein the other end of the rod linkage is mounted to the lever arm at a mechanical advantage distance along the lever arm and away from the hot stick, wherein the first end of the hot stick is adapted to have the housing seat thereon when the hook is engaged with the hot stick connector and the hook retracted to a first retracted position by rotation of the lever arm in a first direction so as to tension the rod linkage, wherein in the first retracted position the hook pulls on the connector to seat the housing onto the first end of the hot stick, and wherein continued and increasing tension on the rod linkage by further rotation of the lever arm in the first direction away from the first end of the hot stick and towards the second end of the hot stick retracts the hook to a second retracted position wherein the connector and piston compress the spring against the return biasing spring force of the spring so as to retract the first jaw away from the second jaw to thereby open the gap, and wherein when the lever arm is rotated in a second direction opposite to the first direction, the return biasing spring force of the spring urges the first jaw towards the second jaw to thereby at least partly close the gap, whereby, with the lever arm rotated in the first direction to open the gap between the first and second jaws, the first and second jaws are positionable to place a conductor into the gap, and whereafter, with Date Recue/Date Received 2021-01-29 the lever arm rotated in the second direction to at least partly close the gap, the conductor is clamped between the first and second jaws.
(a) a ground clamp head, including:
a first jaw, a second jaw in opposed facing relation to the first jaw so as to define a gap therebetween, a housing containing a piston slidably mounted therein, wherein a first end of the piston is mounted to the first jaw, and wherein the housing is coupled to the second jaw by a rigid frame so as to maintain the first and second jaws in their opposed facing relation, a heavy linear spring mounted in the housing and coupled to the piston to resiliently urge the piston and the first jaw towards the second jaw so as to resiliently close the gap between the first and second jaws, wherein the spring has a spring force in the range of 150 to 250 pounds force required to compress the spring, a hot stick connector extending from a second end of the piston opposite the first end of the piston, (b) a hot stick having a hook retractably mounted in a first end of the hot stick, a rod linkage coupled to the hook at one end of the rod linkage, and coupled at the other end of the rod linkage to a lever arm, wherein the lever arm is pivotally mounted on the hot stick, at one Date Recue/Date Received 2021-01-29 end of the lever arm, towards a second end of the hot stick opposite the first end of the hot stick, and wherein the other end of the rod linkage is mounted to the lever arm at a mechanical advantage distance along the lever arm and away from the hot stick, wherein the first end of the hot stick is adapted to have the housing seat thereon when the hook is engaged with the hot stick connector and the hook retracted to a first retracted position by rotation of the lever arm in a first direction so as to tension the rod linkage, wherein in the first retracted position the hook pulls on the connector to seat the housing onto the first end of the hot stick, and wherein continued and increasing tension on the rod linkage by further rotation of the lever arm in the first direction away from the first end of the hot stick and towards the second end of the hot stick retracts the hook to a second retracted position wherein the connector and piston compress the spring against the return biasing spring force of the spring so as to retract the first jaw away from the second jaw to thereby open the gap, and wherein when the lever arm is rotated in a second direction opposite to the first direction, the return biasing spring force of the spring urges the first jaw towards the second jaw to thereby at least partly close the gap, whereby, with the lever arm rotated in the first direction to open the gap between the first and second jaws, the first and second jaws are positionable to place a conductor into the gap, and whereafter, with Date Recue/Date Received 2021-01-29 the lever arm rotated in the second direction to at least partly close the gap, the conductor is clamped between the first and second jaws.
2. A grounding clamp system comprising:
(a) a ground clamp head, including:
a first jaw, a second jaw in opposed facing relation to the first jaw so as to define a gap therebetween, a housing containing a piston slidably mounted therein, wherein a first end of the piston is mounted to the first jaw, and wherein the housing is coupled to the second jaw by a rigid frame so as to maintain the first and second jaws in their opposed facing relation, a spring mounted in the housing and coupled to the piston to resiliently urge the piston and the first jaw towards the second jaw so as to resiliently close the gap between the first and second jaws, wherein the spring has a spring force in the range of 150 to 250 pounds force required to fully compress the spring, and a ground clamp-to-hot stick connector, such as an eye, extending from a second end of the piston opposite the first end of the piston;
and, Date Recue/Date Received 2021-01-29 (b) a hot stick having a shank-mounted hook retractably mounted in a first end of the hot stick, a rod linkage coupled to the hook shank at a first end of the rod linkage, and coupled at the opposite, second end of the rod linkage to a lever arm, wherein the lever arm is pivotally mounted on the hot stick, at a base end of the lever arm, towards a second end of the hot stick opposite the first end of the hot stick, and wherein the second end of the rod linkage is mounted to the lever arm at a mechanical advantage distance along the lever arm and away from the hot stick, wherein the first end of the hot stick is adapted to have the housing seat thereon when the hook is engaged with the ground clamp-to-hot stick connector and the hook retracted to a first retracted position by rotation of the lever arm in a first direction so as to tension the rod linkage, wherein in the first retracted position the hook pulls on the connector to seat the housing onto the first end of the hot stick, and wherein continued and increasing tension on the rod linkage by further rotation of the lever arm in the first direction away from the first end of the hot stick and towards the second end of the hot stick retracts the hook to a second retracted position wherein the connector and piston compress the spring against the return biasing spring force of the spring so as to retract the first jaw away from the second jaw to thereby open the gap, Date Recue/Date Received 2021-01-29 and wherein when the lever arm is rotated in a second direction opposite to the first direction, the return biasing spring force of the spring urges the first jaw towards the second jaw to thereby at least partly close the gap, whereby, with the lever arm rotated in the first direction to open the gap between the first and second jaws, the first and second jaws are positionable to place a conductor into the gap, and whereafter, with the lever arm rotated in the second direction to at least partly close the gap, the conductor is clamped between the first and second jaws.
3.0
(a) a ground clamp head, including:
a first jaw, a second jaw in opposed facing relation to the first jaw so as to define a gap therebetween, a housing containing a piston slidably mounted therein, wherein a first end of the piston is mounted to the first jaw, and wherein the housing is coupled to the second jaw by a rigid frame so as to maintain the first and second jaws in their opposed facing relation, a spring mounted in the housing and coupled to the piston to resiliently urge the piston and the first jaw towards the second jaw so as to resiliently close the gap between the first and second jaws, wherein the spring has a spring force in the range of 150 to 250 pounds force required to fully compress the spring, and a ground clamp-to-hot stick connector, such as an eye, extending from a second end of the piston opposite the first end of the piston;
and, Date Recue/Date Received 2021-01-29 (b) a hot stick having a shank-mounted hook retractably mounted in a first end of the hot stick, a rod linkage coupled to the hook shank at a first end of the rod linkage, and coupled at the opposite, second end of the rod linkage to a lever arm, wherein the lever arm is pivotally mounted on the hot stick, at a base end of the lever arm, towards a second end of the hot stick opposite the first end of the hot stick, and wherein the second end of the rod linkage is mounted to the lever arm at a mechanical advantage distance along the lever arm and away from the hot stick, wherein the first end of the hot stick is adapted to have the housing seat thereon when the hook is engaged with the ground clamp-to-hot stick connector and the hook retracted to a first retracted position by rotation of the lever arm in a first direction so as to tension the rod linkage, wherein in the first retracted position the hook pulls on the connector to seat the housing onto the first end of the hot stick, and wherein continued and increasing tension on the rod linkage by further rotation of the lever arm in the first direction away from the first end of the hot stick and towards the second end of the hot stick retracts the hook to a second retracted position wherein the connector and piston compress the spring against the return biasing spring force of the spring so as to retract the first jaw away from the second jaw to thereby open the gap, Date Recue/Date Received 2021-01-29 and wherein when the lever arm is rotated in a second direction opposite to the first direction, the return biasing spring force of the spring urges the first jaw towards the second jaw to thereby at least partly close the gap, whereby, with the lever arm rotated in the first direction to open the gap between the first and second jaws, the first and second jaws are positionable to place a conductor into the gap, and whereafter, with the lever arm rotated in the second direction to at least partly close the gap, the conductor is clamped between the first and second jaws.
3.0
3. The system of claims 1 or 2 wherein the rod linkage is pivotally mounted to the lever arm.
4.
The system of claim 3 wherein the rod linkage comprises first and second linear rods, wherein the first linear rod is coupled at a first end thereof to the hook shank and is slidably mounted to the first end of the hot stick so as to translate linearly along and parallel to the first end of the hot stick, and wherein the first linear rod is pivotally coupled at a second end thereof, opposite the first end of the first linear rod, to a first end of the second linear rod, the second end of the second linear rod being said pivotally mounted to the lever arm, and wherein the second linear rod is pivotable relative to the first linear rod so as to form an included angle between the second linear rod and the hot stick as the lever arm is rotated to open and close the first and second jaws.
Date Recue/Date Received 2021-01-29
The system of claim 3 wherein the rod linkage comprises first and second linear rods, wherein the first linear rod is coupled at a first end thereof to the hook shank and is slidably mounted to the first end of the hot stick so as to translate linearly along and parallel to the first end of the hot stick, and wherein the first linear rod is pivotally coupled at a second end thereof, opposite the first end of the first linear rod, to a first end of the second linear rod, the second end of the second linear rod being said pivotally mounted to the lever arm, and wherein the second linear rod is pivotable relative to the first linear rod so as to form an included angle between the second linear rod and the hot stick as the lever arm is rotated to open and close the first and second jaws.
Date Recue/Date Received 2021-01-29
5. The system of claim 4 wherein the second end of the hot stick includes a handle end of the hot stick, and wherein the lever arm is an over-center lever arm releasably lockable into an over-center position when fully rotated in the first direction until a handle end of the lever arm is flush against the handle end of the hot stick.
6. The system of claim 5 wherein the piston includes a flange adapted to engage the spring so as to compress the spring upon tensioning of the rod 3.0 linkage.
7. The system of claim 5 wherein the base end of the lever arm is fork, and wherein the fork is pivotally mounted to a pair of correspondingly spaced apart mounting ears on the hot stick, so as to elevate the base end of the lever arm off the hot stick, and to thereby allow the second rod to lie flush along the hot stick when the lever arm is in the over-center and locked position.
8. The system of claim 5 further comprising a hot stick head mounted on the first end of the hot stick, wherein a linear channel is formed in and along the hot stick head, and wherein the first linear rod is slidably mounted in the channel.
9. The system of claim 5 wherein the included angle is a small angle.
Date Recue/Date Received 2021-01-29
Date Recue/Date Received 2021-01-29
10. The system of claim 9 wherein the small angle is substantially in the range of 1 to 3 degrees.
11. A method of using the system of claim 5 by a lineman, comprising the steps of:
providing the system of claim 5, opening the first and second jaws by pulling the lever arm to its over-center and locked position, while holding the hot stick at its second end, manipulating the hot stick so as to position the ground clamp to capture an electrical conductor in the gap between the first and second jaws, unlocking the over-center locked lever arm and rotating the lever arm to de-tension the rod linkage thereby closing the first and second jaws onto the captured conductor.
providing the system of claim 5, opening the first and second jaws by pulling the lever arm to its over-center and locked position, while holding the hot stick at its second end, manipulating the hot stick so as to position the ground clamp to capture an electrical conductor in the gap between the first and second jaws, unlocking the over-center locked lever arm and rotating the lever arm to de-tension the rod linkage thereby closing the first and second jaws onto the captured conductor.
12. The method of claim 11 further comprising reversing the rotation of the lever arm so as to re-tension the rod linkage to thereby open the first and second jaws, whereafter the ground clamp is removed from the conductor.
13. An apparatus as shown, described and/or implied.
14. A method as shown, described and/or implied.
Date Recue/Date Received 2021-01-29
Date Recue/Date Received 2021-01-29
15. A system as shown, described and/or implied.
Date Recue/Date Received 2021-01-29
Date Recue/Date Received 2021-01-29
Priority Applications (12)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3107483A CA3107483A1 (en) | 2021-01-29 | 2021-01-29 | Spring loaded ground clamp |
| CA3133635A CA3133635A1 (en) | 2021-01-29 | 2021-10-08 | Spring loaded ground clamp |
| AU2022214295A AU2022214295A1 (en) | 2021-01-29 | 2022-01-27 | Spring loaded ground clamp |
| CR20230369A CR20230369A (en) | 2021-01-29 | 2022-01-27 | Spring loaded ground clamp |
| MX2023008987A MX2023008987A (en) | 2021-01-29 | 2022-01-27 | Spring loaded ground clamp. |
| EP22746618.2A EP4282033A1 (en) | 2021-01-29 | 2022-01-27 | Spring loaded ground clamp |
| PCT/US2022/014120 WO2022165053A1 (en) | 2021-01-29 | 2022-01-27 | Spring loaded ground clamp |
| US17/586,456 US11817665B2 (en) | 2021-01-29 | 2022-01-27 | Spring loaded ground clamp |
| CA3174287A CA3174287A1 (en) | 2021-01-29 | 2022-01-27 | Spring loaded ground clamp |
| CL2023002237A CL2023002237A1 (en) | 2021-01-29 | 2023-07-28 | Spring Loaded Grounding Clamp |
| CONC2023/0010070A CO2023010070A2 (en) | 2021-01-29 | 2023-07-28 | Spring Loaded Ground Clamp |
| US18/483,457 US20240039179A1 (en) | 2021-01-29 | 2023-10-09 | Spring loaded ground clamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3107483A CA3107483A1 (en) | 2021-01-29 | 2021-01-29 | Spring loaded ground clamp |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA3107483A1 true CA3107483A1 (en) | 2022-07-29 |
Family
ID=82593852
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA3107483A Pending CA3107483A1 (en) | 2021-01-29 | 2021-01-29 | Spring loaded ground clamp |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA3107483A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115939798A (en) * | 2023-03-09 | 2023-04-07 | 江天科技有限公司 | Graphene grounding device |
| WO2024105291A1 (en) * | 2022-11-14 | 2024-05-23 | Red Eléctrica de España, S.A.U. | Ground connection device and hoisting device for said ground connection device |
| CN118508116A (en) * | 2024-07-18 | 2024-08-16 | 国网安徽省电力有限公司临泉县供电公司 | Grounding wire clamp structure convenient to hang and detach and grounding wire |
| CN118508116B (en) * | 2024-07-18 | 2024-09-24 | 国网安徽省电力有限公司临泉县供电公司 | Grounding wire clamp structure convenient to hang and detach and grounding wire |
-
2021
- 2021-01-29 CA CA3107483A patent/CA3107483A1/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024105291A1 (en) * | 2022-11-14 | 2024-05-23 | Red Eléctrica de España, S.A.U. | Ground connection device and hoisting device for said ground connection device |
| CN115939798A (en) * | 2023-03-09 | 2023-04-07 | 江天科技有限公司 | Graphene grounding device |
| CN118508116A (en) * | 2024-07-18 | 2024-08-16 | 国网安徽省电力有限公司临泉县供电公司 | Grounding wire clamp structure convenient to hang and detach and grounding wire |
| CN118508116B (en) * | 2024-07-18 | 2024-09-24 | 国网安徽省电力有限公司临泉县供电公司 | Grounding wire clamp structure convenient to hang and detach and grounding wire |
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