Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a clamp for power transmission
lines. The invention provides a structure which is inherently
safer to use with live transmission lines than many of the clamps
presently installed, because the clamp may be manipulated by the
line worker using just one hand. This feature greatly reduces
the risk of forming an electric circuit through the body of the
line worker.
The invention provides a clamp for an electrical transmission
line, comprising a body having a socket for attachment of an
electrical insulator, a concavely curved saddle for receiving the
transmission line, and an aperture defined transversely through
the body, preferably adjacent the saddle. The aperture has an
upper portion which is preferably square in cross section, but
which has at least one flat internal surface and a lower portion
which is circular in cross section, a transverse surface being
defined at the junction of the two portions. A rod having upper
and lower threaded portions separated by an annular flange is
insertable through the aperture so that the lower portion may
extend beyond the bottom of the aperture and the flange may
engage the transverse surface. The rod has a nut which is
affixed to the lower portion extending through the aperture
preferably by means of a pin which passes through a hole defined
transversely through the lower portion and nut. A clamping arm
has a leg which is insertable in the upper portion of the
aperture in the body. The leg has a longitudinal bore threaded
- to receive the upper portion of the rod. The leg has an upper
portion which is preferably square in cross section, but having a
cross sectional shape which matches that of the upper aperture
portion. The leg has a lower portion which is rounded and
preferably circular in cross section. The clamping arm has a
transmission line keeper positionable over the saddle to clamp
the transmission line in the saddle. The keeper extends from the
upper portion of the leg and is oriented transversely to it. The
clamping arm coacts with the rod to permit the leg to travel
longitudinally in the aperture and to permit the keeper to be
pivoted about the rod when the leg is near the end of its travel
on the upper threaded portion. This pivotability of the arm is
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afforded by the rounded lower portion of the leg which may be
rotated in the aperture.
Brief Description of the Drawings
Figure 1 is an exploded perspective view of a clamp in accordance
with the invention;
Figure 2 is a side elevation, partially broken away, of the
assembled clamp of Fig. 1; and
Figure 3 is a side elevation of the clamp showing the keeper
being pivoted about the bolt assembly.
The preferred embodiment of the clamp of the invention comprises
a body 10 having a socket 11 formed therein for receiving an
electrical insulator 12 (Fig. 2). The body 10 has a concavely
curved saddle 15 for receiving a transmission line 16. The
saddle 15 is preferably lined with a rubberized insulating
material 17. If the body 10 is made of metal, the insulating
lining 17 for the saddle 15 is usually required to minimize radio
interference. A carbon impregnated rubber lining 17 has been
found to be suitable in this regard.
An aperture 20 is defined transversely through the body 10
preferably ad]acent the saddle 15 such as shown in the Figures at
an upwardly curving side of the saddle 15. The aperture 20 has
an upper portion 21 which is not circular and is preferably
square in cross section, and a lower portion 22 which is circular
in cross section. The junction of the upper and lower portions
21 and 22 defines a transverse surface 24 bounded by the walls of
the upper portion 21 and having the top edge of the lower portion
22 located centrally therein.
A threaded rod 27 has an upper portion 28 and a lower portion 29
separated by an annular flange 30. The rod is insertable through
the aperture 20 so that the lower portion 29 extends beyond the
bottom of the aperture 20. The flange 30 is engagable with the
surface 24 and prevents the rod 27 from passing completely
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through the aperture 20. Preferably a lock washer 35 is provided
over the lower portion 29 of the rod 27 which extends beyond the
bottom of the aperture 20, and a nut 36 is attached to the end of
the rod 27. While the nut 36 may be attached to the rod 27 in a
variety of ways, a preferred means of attachment is to pin the
nut 36 in place. Thus, transverse holes 38 and 39 are provided
through the nut 36 and rod 27 so that a pin 41 may be inserted
therethrough. The attachment of the nut 36 to the lower end of
the rod 27 renders the assembly a bolt which is captive about the
lower aperture portion 22.
A clamping arm 45 has a leg 46 which is insertable in the upper
portion 21 of the aperture 20. The leg 46 has a longitudinal
bore 48 running centrally thereof from the bottom of the leg 46
to near, but preferably not through, the top of the leg 46. The
bore 48 is threaded to accept the upper portion 28 of the rod
27. The leg 46 has an upper portion 51 having a cross sectional
shape which is compatible with that of the upper portion 21 of
the aperture 20, and having a lower portion 52 which is circular
in cross section. The clamping arm 45 has a transmission line
keeper 55 which is positionable over the saddle 15 to clamp the
transmission line 16 in place (Fig. 2). The keeper 55 extends
from the upper portion 51 of the leg 46 and is oriented
transversely to it. Preferably, the keeper 55 has a concavely
curved bottom surface 57 compatible with the rounded contour of
the transmission line 16. The keeper 55 also preferably has a
length matching the seat width of the saddle 15 so that the line
16 may be firmly clamped about the entire length which is seated
therein.
The clamp is operated by rotating the rod 27 by means of the nut
30 36 affixed to it. Since the rod 27 and nut 36 assembly is
captive about the lower aperture portion 22, rotation thereof
causes the clamping arm 45 to move upwardly or downwardly along
the length of the upper portion 28 of the rod 27. When inserting
a transmission line 16 into the saddle 15, the clamping arm 45 is
35 run up the rod 27 until the upper portion 51 of the leg 46 clears
the top of the aperture 20 enabling the keeper 55 to be pivoted
away from the saddle 15 about the lower circular portion 52 of
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303S
the leg 46 (Fig. 3). With the line 16 in place in the saddle 15,
the keeper 55 is then swung over the saddle 15 and the rod 27 is
rotated by means of the affixed nut 36 to cause the leg 45 to
move downwardly into the aperture 20. The upper portions 51 and
21 of the leg 46 and the aperture 20 coact to prevent rotation of
the leg 46, and hence, the clamping arm 45 about the axis of the
rod 27. While the simplest and preferred cross sectional shape
for these upper portions 51 and 21 is square or rectangular, it
should be apparent that the invention includes any shape which
affords the desired function. As the arm 45 is screwed down the
rod 27, the keeper 55 comes in contact with the line 16 and is
tightened in place by the nut 36 preferably with the assistance
of the lock washer 35.
From the foregoing description variations of the preferred
embodiment will be apparent to the skilled person. These
variations within the scope of the invention are defined in the
claims which follow.
