C-clamp ground adapters

A ground adapter is used in conjunction with a C-clamp for providing a connection between a ground cable from, for example an electric arc welding machine, to a ground object such as a workpiece. The ground adapter and ground object are firmly retained in contact with one another by a conventional C-clamp. The ground adapter is comprised of a ground base which is designed to receive one or more electrical cables. A plurality of adjustable cowling members may be disposed about one pad or foot of the C-clamp and are releasably secured to the ground base. The location of cowling members on the ground base is adjustable which enables use of the ground adapter with C-clamps having pads of varying sizes. Upon tightening the spindle or threaded portion of the C-clamp against the ground adapter, the cowling members of which are in firm contact with one pad of the clamp and against the ground base, a reliable physical and electrical contact is maintained between the ground adapter and the ground object thereby enabling completion of an electrical circuit as, for example, is required during electric arc welding operations.

BACKGROUND OF THE INVENTION 
The present invention relates to ground clamps and, more particularly, to 
ground adapters for use with C-clamps in connecting electrical cables to a 
ground object. 
In order to complete an electrical circuit for enabling performance of 
electric arc welding and metal removing operations, it is necessary to 
connect one terminal of a welding machine (power supply) to ground 
potential. In electric arc welding operations, it is common to connect one 
terminal of the welding machine to an electrode while the remaining 
terminal is connected through a suitable adapter to a ground object, such 
as the workpiece. However, as extremely high currents, up to 3,000 amps 
are generated during the course of such operations, it is necessary to 
effect a secure connection between the ground object and electrical ground 
cable which connection does not produce excessive heat or significant 
voltage drops thereacross. 
C-clamp devices have been used to connect electrical cables to a ground 
object. Previously, this connection has been effected by securing the 
cable to the body of the C-clamp such that upon tightening the spindle, a 
ground object is retained between a pad and foot portion of the C-clamp 
body. Another type of prior art device is shown in U.S. Pat. No. 2,420,895 
wherein a special C-clamp and connecting lug are utilized. It has been 
found that prior art ground devices have suffered from the disadvantage of 
generating excessive amounts of heat as well as producing undesirable 
voltage drops simply due to the resistance of the ground device. 
Furthermore, prior art ground devices utilized with C-clamps have not been 
sufficiently flexible in that particular ground devices have been 
generally suitable only for a single sized C-clamp and have not been found 
suitable for use with a wide range of C-clamp sizes. This has been 
particularly true with respect to relatively large C-clamps which have 
correspondingly large feet or pads. Accordingly, prior art ground clamping 
devices have not proven effective in use with C-clamps of sizes required 
to retain relatively large ground objects or workpieces, e.g. 4-6 inches 
thick, in contact with a typical prior art ground lug or device. 
Therefore, it has been found that a clear need exists for a ground adapter 
useable with a wide variety of sizes of conventional C-clamps. 
OBJECTS OF THE INVENTION 
It is an object of the present invention to provide improved ground 
adapters for connecting electrical cables to ground objects. 
It is another object of the present invention to provide improved ground 
adapters suitable for use with C-clamps of, and having feet or pads of, a 
wide variety of sizes. 
It is still another object of the present invention to provide improved 
ground adapters suitable for heavy duty, high current use, for carrying 
currents of up to 3,000 amps. from an electrical cable to a ground object 
without developing excessive heat or significant voltage drops across the 
adapter. 
It is yet another object of the present invention to provide improved 
adapters of simple construction yet enabling firm, reliable contact 
between one or more electrical cables and a ground object. 
Other objects of the present invention will become apparent from the 
detailed description of an exemplary embodiment thereof which follows and 
the novel features of the present invention will be particularly pointed 
out in conjunction with the claims appended hereto. 
SUMMARY 
In accordance with the present invention, a C-clamp ground adapter for 
connecting electrical cables to a ground object upon retention of said 
adapter and ground object in a C-clamp comprises a ground base, means for 
connecting one or more electrical cables to the ground base, and a 
plurality of adjustable cowling members for receiving one pad of a 
C-clamp, the cowling members being releaseably secured to said ground base 
to retain the received pad in contact with the base with the location of 
the secured cowling members determined by the size of the received pad. 
Thus, by providing such adjustable cowling members, C-clamps having pads 
of various sizes may be firmly and reliably secured to the ground base of 
the adapter in accordance with the present invention. In this manner a 
high degree of flexibility of use of the instant ground adapter is 
achieved. The ground base is preferably comprised of copper although other 
electrically conductive materials which do not generate excessive amounts 
of heat or produce significant voltage drops upon high current flow 
therethrough may be utilized as well. In addition, one or more electrical 
cables, such as the ground cables connected to an electric arc welding or 
metal removing machine or power supply may be connected to the ground base 
of the adapter. Suitable retention screw means may be utilized to effect 
the connection of such electrical cables to the ground base although other 
electrical contact devices may also be utilized in accordance with the 
teachings of the present invention. 
The cowling members of the ground adapter according to the present 
invention may be of unitary construction and preferably include flat and 
angularly ascending portions, the latter portion being effective to engage 
a similarly angled side of the pad or foot of a conventional C-clamp. 
Preferably, a pair of cowling members are utilized in connection with the 
instant ground adapter, although more than two of such cowling members are 
provided with a plurality of slots or other apertures such that screws or 
other adjustable fastening members may extend therethrough to engage 
threaded portions or the like of the ground base. In this manner, the 
position of the cowling members on the ground base and hence, the size of 
a housing for the pad or foot of the C-clamp to be received in such 
housing (cowling members and ground base) may be adjustably set thus 
enabling the ground adapter of the present invention to be utilized with 
any of a wide variety of sizes of C-clamps.

DESCRIPTION OF PREFERRED EMBODIMENT 
Referring now to FIG. 1 of the drawing, illustrated therein is an exemplary 
embodiment of a ground adapter 10 which is provided with a C-clamp 11 
having a typical threaded portion or spindle 12 for securely maintaining 
adapter 10 and ground object 16 which may comprise a workpiece in 
electrical and physical contact. A source of electrical current, which may 
comprise an electric arc welding machine 14, or other power supply such as 
is used in connection with carbon arc metal removing processes, is 
provided with one terminal thereof connected through cable 17 to an 
electrode 15 while the other terminal of machine 14 is connected through 
cable 18 to ground adapter 10. In this manner, ground object or workpiece 
16 is coupled through adapter 10 and cable 18 to the appropriate terminal 
of arc welding machine 14. Therefore, upon supplying a suitable current 
through cable 17 and electrode 15, a complete electrical circuit is 
provided by way of workpiece or ground object 16, ground adapter 10 and 
electrical cable 18. 
Referring now to FIG. 2, illustrated therein is an exemplary embodiment of 
a ground adapter 10 firmly connected to the foot or pad 20 extending from 
threaded portion 12 of a typical C-clamp. Ground adapter 10 is generally 
comprised of a ground base 21, adjustable cowling members 22 and 23, a 
cavity 26 and approriate fastening means and suitable apertures therefor 
as will be subsequently described. Ground base 21 is preferably a 
substantially solid mass of an electrically conductive material such as 
copper which does not generate excessive heat upon passage of electrical 
currents up to 3,000 amps. therethrough. Although ground base 21 is 
preferably comprised of copper, it is understood that other electrically 
conductive materials may also be utilized in lieu of copper. Ground base 
21 is preferably provided with a suitable cavity 26 for receiving an end 
of an electrical cable such as cable 18 illustrated in FIG. 1. Commonly, 
the insulation about the end of such a cable is stripped away such that a 
screw 28 or other suitable retention member or device may be inserted 
through one or more apertures in ground base 21 thereby engaging such 
stripped cable portion and providing a firm, reliable electrical contact 
between the stripped portion and ground base 21. A further retaining screw 
27 is preferably inserted into a suitably threaded aperture in ground base 
21 and is effective to provide a gripping or retaining force against an 
unstripped or insulated portion of the cable received in cavity 26. It is 
within the scope of the present invention to utilize fastening or 
connecting means other than screws or the like, to provide the necessary 
electrical contact between ground base 21 and a cable received in cavity 
26 thereof. In addition, it will be understood that more than one cavity 
26 may be formed in a suitable portion of ground base 21 such that a 
corresponding plurality of electrical cables may be received in and 
connected to ground base 21. 
Adjustable cowling members 22 and 23 are preferably provided with a 
relatively lower or flat portion having a plurality of slots or the like 
24 formed therein and an angularly ascending portion 22' and 23', 
respectively. A corresponding number of screws 19 are preferably provided 
such that upon tightening screws 19 in slots 24, the position or location 
of cowling members 22 and 23 on ground base 21 may be adjustably fixed. 
The angularly ascending portions 22' 23' of the cowling members are 
preferably of a shape or geometry which corresponds to the geometry of the 
sloping side portions of the pads or feet of typical conventional 
C-clamps. It will be understood that although two cowling members 22 and 
23 are illustrated in connection with this exemplary embodiment of the 
ground adapter according to the present invention, three or more 
symmetrical, adjustable cowling members may be provided as well. In 
addition, although cowling members 22 and 23 are preferably of a unitary 
construction, other types of construction may be utilized. 
In order to secure ground adapter 10 to the pad or foot 20 of a C-clamp 11 
(FIG. 1), screws 19 are loosened or removed thereby enabling adjustable 
cowling members 22 and 23 to be freely movable along or removable from the 
top surface of ground base 21. C-clamp pad 20 is placed on the upper 
surface of ground base 21 and adjustable cowling members 22 and 23 are 
fitted around pad 20 such that this pad is effectively received in a 
housing or shroud formed by cowling members 22 and 23. Upon adjustment or 
tightening of screws 19, adjustable cowling members 22 and 23 will be 
secured against the sloping surface of pad 20 thereby releasably securing 
ground base 21 to pad 20 of C-clamp 11. As the position or location on 
ground base 21 at which cowling members 22 and 23 may be set is adjustable 
or variable as a consequence of providing slots 24 therein, it will be 
appreciated that the ground adapter comprised of base 21 and adjustable 
cowling members 22 and 23 is highly flexible and may be utilized to 
receive the pad of C-clamps of a wide range of sizes. 
A further exemplary embodiment of the ground adapter according to the 
present invention is illustrated in FIG. 3. As certain portions of the 
ground adapter shown in this Figure have been discussed in connection with 
the adapter illustrated in FIGS. 1 and 2, further discussion of such 
portions is deemed unnecessary. With respect to FIG. 3, it is noted that 
ground base 21 is provided with an enlarged cable receiving portion 29 
which in turn is provided with a stepped internal cavity 31. Preferably, a 
threaded aperture 32 is adapted to receive a small socket head screw 33 
which in turn engages and retains the unstripped or insulated portion of a 
cable inserted into cavity 31. In addition, threaded apertures 34 and 35 
extend through portion 29 into cavity 31 such that upon appropriate 
adjustment of large dome or clamp screws 36 and 37, electrical and 
physical contact between such screws and the stripped, conductive portion 
of a cable inserted into cavity 31 is assured. In this manner, ground base 
21 is retained in physical and electrical contact with a cable inserted 
into cavity 31. As mentioned heretofore, such a cable may comprise the 
ground cable of an electric arc welding machine or a power supply of an 
electric arc metal removing apparatus. 
Preferably, ground base 21 is provided with a plurality of threaded 
apertures 24' for receiving cowling screws 19 as well as a slight 
depression 30 as illustrated in FIG. 3. The purpose of depression 30, 
which may be of a size and geometry corresponding to the largest C-clamp 
pad to be retained by adjustable cowling members 22 and 23 in contact with 
ground base 21, is to increase the holding action and consequently reduce 
slippage of such a pad retained in ground adapter 10. 
The foregoing and other various changes in form and details may be made 
without departing from the spirit and scope of the present invention. 
Consequently, it is intended that the appended claims be interpreted as 
including all such changes and modifications.