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Патент USA US2137840

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Nov. 22,l 1938-.
Filed Feb. s, 1957
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Patented Nov. 22, 1938
2,137,840 `
eA'i‘Enr OFFICE `
Neil G. Hayes, Bridgeport, Conn.
. „
Application February 8, 1937, Serial No. 124,590 '
2 Claims.
(Cl. 247-1)
This invention relates to ground clamps, or . yet designed so as properly to be clamped to any
connectors for grounding a conduit and a con
one oi a Vnumber oli” pipes of different diameters,
ductor in an electrical system to a water or other
grounding pipe.
Previous ground clamps of this kind have com
prised a metal ñxture securable to the ground
ing pipe, a metal device for having connected
the coupling screw is so located as not to inter
fere with either` the pipe-clamping screw or a
pipecradled in the ñxture and clamped therein
by- directly applied thrust of the pipe-clamping
thereto `a conductor and a conduit oi the elec
screw, even when the pipe‘is the largest one of
the several sizes of pipe for which the ñxture is
trical system _to be grounded, and means for cou
pling the fixture and the device so as to secure
them together in any one of several angular ad
justments between the saine.
An object of the invention is to provide such
a ground clamp, but one comprising principally
Still another feature of the invention is vthe
provision of projections arranged within and
spaced along the length of the curved claw and
having their tops so disposed relative to the gen
eral curvature of the claw that for each of a
two simpla‘rugged and easily finished metal _ plurality of pipes of different diameters a special
parts, as castings, one to constitute the fixture
and the other to constitute the device, but never
plurality of said projections engages the round
ing of the pipe when the pipe-clamping screw is
theless, a clamp so constructed that a rounding
of the pipe is Seized ‘in a curved part of the fix
Ature, and this by tightening of a single screw
to force an end of that screw directly against
Various other objects and advantages will’
hereinafter appear.
In the accompanying drawing
Figure l is an elevational view showing in iull
lines a grounding pipe and a ñtting according to
the invention applied thereto,---this View indicat
ing, in broken lines, various of the many possible 25
angular adjustments of the device for receiving
the pipe.
A feature of the new ground clamp is the in
clusion of a pipe-embracing fixture having sub
stantially the shape of an oval open at one side.
Such oval provides, `at one end and at its closed
side near that end, a curved claw for cradling
therein apart of the rounding of a pipe. The
pipe-clamping screw is placed on the iiXture so
as to pass through an end portion oi the oval
opposite the claw and to be directed toward a
point on the claw intermediate the ends thereof.
Then it is possible to hook the claw around the
pipe preparatory to tightening the screw, there
3:, `by to facilitate connection and easy securement
„ of` the fixture to the pipe.
Another feature of the invention is the attach
ment, to the closed side of the oval, and at a
point in that side nearer to the screw than to
.m the claw, of the device for receiving the con
ductor and conduit to be grounded. At this part
of the ñxture the bulk of metal is considerable
so as to give proper strength to the oval. This
bulk of metal makes it practicable to have the
.15 means for attaching the device to the iixture in
clude‘ merely two flat table-like portions one at
the’ exterior of the iixture, and the other on the
bottom‘of the device, with both ci these tables in
direct `face engagement, additional to a cou
a conductor and, conduit to be grounded.
` `
Fig. 2 is also an elevational view, but one look- `
ingtoward the left in Fig. 1, and partially broken
away and partially in section.
Fig. 3 is a top plan view of the ñtting as shown
in Fig. 1, with the grounding pipe shown in sec-V
Fig. 4; is a View similar to Fig. 1, but-showing a
Fig. 5 is a` view similar to Fig. 2, showing said v
Fig. 6 is an elevational view oi.’` said modification
as shown in full lines in Fig. 4, but showing cer
tain parts in section according to the line B of
Fig. 5.
In the form of the invention illustrated herein,
which is the form at present preferred, theïñx
ture It, which is the element of the ground ñt
ting to loe clamped to a grounding pipe or rod,
such, for instance, as the water pipe Il, is coin
prised oi a single casting I2 and a clamp screw
As shown best in Fig. 3, the fixture I0 is of
pling screw for the fixture and the device and
substantially the shape of an oval open at one.
passing through both table-like portions. Pref
side, thereby to provide a curved claw I4 for
cradling therein a part of the rounding of the
pipe II. The screw I3 passes through a tapped
hole in the end portion I5 of the oval opposite the
claw. `This hole is directed toward a> point on’
erably, this screw is directed toward a point in
termediate the ends of the opening in the open
side- of the oval, because then, with the oval
56 shaped for maximum strength and lightness, and
the claw intermediate the ends thereof, so that
when the screw is tightened against a pipe in the
claw, the thrust of the screw will be such as to
hold the latter to retenion by the claw. The
head I3’ of the screw is shown as hexagonal for
the application of a wrench, and also kerfed,
to allow of the use of a screw driver, in tightening
one of the advantages of which has already been
mentioned, also coacts with the projections on
the inner face of the curved claw to make it
possible to provide a fixture I0 which is only very
little larger than the largest pipe to Which the
ñxture is intended to be secured. Note in this
up the screw.
in the form of the invention shown, and which
is placed to the left of the projection 23 of the
curved claw I4. This concavity acts as a receptor 10
for the rounding of a pipe of very large diameter
The claw curvature merges with a curvature
10 down along the side I6 of the oval, and this,
among other advantages which will be later men
tioned, gives maximum strength and lightness to
the fixture as a Whole.
The curved claw I4 allows the end of the ñx
ture carrying the same to be hooked-over the
pipe II preparatory to tightening up the screw
I3. 'I'his facilitates quick and easy attachment
of the fixture to the pipe, to a degree suñicient
to prevent accidental loss of the ñxture from or
unintended slipping of the same along or around
the pipe, by a preliminary tightening of the screw
I3. The fixture I0 may then be shifted if and as
required to give the same exactly the desired
position on the pipe II, whereupon the screwv I3
may be fully tightened up, and locked as thus
tightened, for which purpose a clamp nut I1 is
preferably carried by the screw as shown.
In order to insure that the curved claw I4 may
be able to take pipes of different diameters, but
will always have not only a hook engagement with,
but a definite cradling hold on the pipe therein,
the claw is provided at its inner face with a plu
rality of spaced projections.
The projections
shown, marked I8, I9, 20, 2|, 22 and 23, are so
spaced along the length of the claw, and the tops
of the projections are so arranged, that one pro
jection, as thev projection I9, intermediate two
other projections, as the projections IB and 20,
has its top located to lie outside a circle defined
by the tops of the two projections last-mentioned
when such circle is so drawn as to have the pro
jections last-mentioned exterior` thereto. The
various projections, also, it will be noted, are
shown as irregularly spaced along the curved
claw. By such an arrangement, insurance is had
that a pipe of one diameter will be cradled Within
the curved claw on a plurality of fairly widely
spaced projections, and a pipe of another diame
ter will be cradled within the claw on another
plurality of fairly widely spaced projections; and
50 at the same time, in either case, the pipe will be
held in the claw so that a prolongation of the
center line of the screw I3 will substantially in
tersect the axis of the pipe. Such a condition
is illustrated in Fig. 3 in connection with the pipe
55 I I, where the same is engaged by the screw I 3 as
described, and at the same time is cradled within
the curved claw on the projections I9 and 2|. A
smaller pipe, for instance, would be thus cradled
on the projections I9 and 20. Similarly, a larger
pipe than the pipe I I would be cradled on the
projections I9 and 2U, while a still larger pipe
would be cradled on the projections I9 and 22,
and a yet larger pipe on the projections I8 and
` Thus a curved claw may be employed, for true
hook engagement with the grounding pipe, and
at the same time this claw is adapted to receive
pipes of widely different diameters, but always in
away to avoid having merely a single-line con
70 tact with the pipe where the latter is of a size
such that its rounding is of less degree of curva
ture than the inner face of the claw.
'I’he merging of the curvature of the claw with
the -curvature down along the side I6 of the oval,
connection, the concavity 24 which is provided
compared with the pipe II, when this very large
pipe is cradled in the curved claw on the projec
tions I8 and 23.
The concavity 24 is down along the side I6 of 15
the oval close to the clamp screw I3, and so coacts
with the generally strengthening curvature of
this oval side I6 to provide a part 25 of the oval
which, Without being of excessive weight, is of
adequate bulk to permit the ñtting to have a 20
very simple means for properly coupling, to the
ñxture I0, the device for receiving the conductor
and conduit to be grounded to the pile II, In
the form of the invention shown in Figs. l to 3,
this device is indicated generally by the reference 25
character 26. In the embodiment illustrated in
Figs. 4 and 6, this device is indicated generally
at 26’.
The attaching means for securing the device 26
or 26’ to the fixture I0, and for adjusting the 30
former angularly as required relatively to the
latter, for instance, as shown in broken lines in
Figs. 1 and 4, comprises merely a flat table-like
portion 21 at the exterior of the part 25 of the
ñxture I il, a similar table-like portion at the bot 35
tom of the device 26 or 26’ and placed in direct
face engagement with the table-like portion 21
on the ñxture, and a screw 28 having, like the
pipe-clamping screw I3, a kerfed bolt head 28'.
As shown in Figs. 2 and 5, this screw, passed 40
through a cylindrical hole in the device 26 or 26',
is in threaded engagement with a tapped hole
through the part 25 of the fixture IU.
Referring more particularly to the device 26
of Figs. 1, 2 and 3, this is shown as consisting of a 45
single part comprising a threaded nipple 26a and
a leaf-extension 26h.
On the bottom of the ex
tension 2Gb, is the flat table-like portion afore
said which is placed in direct face engagement
with the flat table-like portion 21 on the iixture 50
IIJ, and through this extension 2Gb is passed the
screw 23 which couples the device 2B and the iìx
ture Il). For strengthening purposes, webs or
fillets 28C may be provided, but these should not
obstruct free access to the extension 28h.
The device 26 is designed for use with a pipe
conduit 29 to be grounded, and this nipple is
threaded for taking a threaded end of the con
duit. In the present case, the nipple is shown as
being interiorly threaded, but it will be under 60
stood that it may be exteriorly threaded, or both
interiorly and exteriorly threaded, in which last
case a nipple of one size may accommodate, with
out the use of reducers. two sizes of pipe,
To complete grounding of the electrical system, 65
in the form of the invention shown in Figs. 1, ,»2
and 3, a grounding wire 3U carried in the con- .
duit 29 may have its end coiled and placed under
the head of the coupling screw 28, but prefera
bly it is soldered in a lug 3l, and this lug has an 70
aperture through which the coupling screw ex
tends. Thus, when the coupling screw is tight
ened to secure the device 26 on the fixture I0, and
to have the conduit 29 extended at the desired
angle to the grounding pipe II, both the conduit 75
29 and the wire 3| are grounded through the
ñxture Ill to the grounding pipe I I. In the struc
ture illustrated, a split washer 32 is interposed
between the lug 3I and the head of the screw 28,
forlocking the screw to its finally tightened po
The flat table-like portions which are in direct
face engagement between the fixture I0 and the
device 25 are easily wiped clean if dirty, and so
10 there can be no accidental insulation between
these parts. The upper face of the extension
26a of the device 26 need not be iinished to a
smooth surface, or otherwise specially formed to
facilitate cleaning, as the grounding current will
15 pass from the lug 3I to the washer 32 and to the
head of the screw 28, and through the screw to
the fixture I0 and thence to the grounding pipe I I.
When the parts are ñnally all coupled and as
sembled as described, even relative to a ground
20 ing pipe much larger than the pipe II, as a
grounding pipe so large that a part of its round
ing extends well into the concavity 24, it will be
noted that the coupling screw 28, when fully
tightened up, does not protrude far enough into
25 this concavity to limit the capacity of the ñxture
I0 to a grounding pipe smaller than permitted
by the concavity with the screw 28 retracted be
yond the concavity. On the other hand, the
thickness of the part 25 of the fixture in the
However, the upper face of the leaf-extension
26h’ of the device 26 is upwardly peripherally
cupped and carries a central boss 26o' surround
ing the opening for the screw 28. As shown, this
boss is of somewhat less height than the rim of
the cup. Between the boss and the cup rim there
is an annular groove 26d’. Sleeved on the upper
end of the screw 28 is a disk 36. The groove
26d’ is of such a depth, relative to the height of
the boss and to the thickness of the grounding 10
wire 33, that when a bared end length 33’ of the
latter is curled and laid in the groove as illus
trated in Figs. 5 and 6, and the screw l28 is tight
ened to force the disk 36 into the cup, the disk
will squeeze the curl of the wire down tight in
the groove and tight against the lower face of
the disk, before the disk reaches the top of the
boss 26e’. As shown at 31, a split washer is de
sirably interposed between the disk 36 and the
head of the screw, to lock the screw to its finally 20
tightened position.
Variations and modifications may be made
within the scope of this invention and portions
of the improvements may be used without others.
I claim:
1. A. ground fitting comprising a pipe-engag
ing fixture of substantially C-shape and hav
ing a pipe-engaging surface along the inner face
of the curved end and one side thereof, said sur
30 direction of advance of the screw 28 gives the
face comprising pipe-engaging projections spaced 30
latter ample thread engagement with the tapped
hole through the part 25; and this is another ad
vantage resulting from the shaping of the fixture
ID to provide, in connection with the curved
35 claw I4, a side I6 having a curvature merging
along the length of the surface and having their
tops so located within the clamp that the tops of
the first projection and second projection define
a circle corresponding to one pipe diameter and
the top of a projection between the first and 35
with the curvature of the claw in a way to give i second projections and the top of a projection
the fixture maximum lightness yet adequate beyond one of said ñrst and second projections
strength all over.
deñne a circle corresponding to another pipe
Referring now to the modification shown in diameter, said fixture having a tapped hole in
40 Figs. 4, 5 and 6, and particularly to the device the end portion opposite the pipe-engaging por 40
26', the substitution of which, for the device 26 tion; a clamping screw in said hole; a device on
of Figs. 1, 2 and 3, constitutes such modification: the ñxture adjacent the clamping screw for re
The device 26’ is adapted particularly for use ceiving the grounding conductor and conduit;
when the grounding wire is a wire 33 covered by and means for securing and angularly adjusting
a flexible metal conduit 34, so that both this wire
and this conduit are the ones to be grounded.
The device 26’ includes a cylindrical neck 26a’
upstanding from one end of a leaf-extension 26h'.
In order to secure the conduit 34 in and ground
the saine to the neck, the latter is _provided with
a set screw 35.
The leaf-extension 26h’ has on
its bottom a ñat table-portion like that of the
device 26, and through this leaf-extension is sent
a screw 28 as in the case of the device last-men
Thus, the attachment of the device 26' to the
ñxture IU, and a setting of the device to the
angle desired relative to the pipe Il, is obtained
as already described in connection with the de
60 vice 26,
the device on the ñtting.
2. A ground fitting comprising a pipe-engag
ing fixture of substantially C-shape and having a
pipe-engaging surface along the inner face of
the curved end and one side thereof, said sur
face comprising pipe-engaging projections ir
regularly spaced along the length of said sur
face; a projection intermediate two other pro
jections having its top located to lie outside a
circle deñned by the top of the two projections
last-mentioned when said circle is so drawn as 55
to have the projections last-named exterior
thereto; and means for securing a grounding
conductor or conduit thereto.
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