Note: Descriptions are shown in the official language in which they were submitted.
CA 02361027 2001-11-05
SCAFFOLDING WEDGE CLAMP
FIELD OF THE INVENTION
The invention relates to a two-way clamp for holding two pipes perpendicular
to each other,
especially where the two pipes form part of a scaffolding framework.
BACKGROUND OF THE INVENTION
Scaffolding clamps are two-way clamps designed to secure scaffolding pipes at
right angles
to each other. As the pipes are key weight-bearing structural elements, it is
essential that
they be firmly linked together. Scaffolding clamps typically consist of a
central body to which
is attached two clamps. The clamps are oriented at right angles to each other
such that
each clamp can encircle a pipe, keeping the two pipes locked in position.
Two common types of scaffolding clamps are bolt clamps and wedge clamps. Bolt
clamps
consist of a central body with two hinged clamping arms. Each clamping arm is
attached to
one end of the central body with a hinge, and to the other end of the central
body with a bolt.
The clamps are closed by passing the bolt through a hole in the clamping arm,
and
tightening a nut to prevent the clamping arm from'slipping off the bolt. The
installation of a
bolt clamp is a labour-intensive task, requiring the tightening of each nut
with a wrench.
Wedge clamps, by contrast, are much more easily fastened. Wedge clamps consist
of two
clamping arms hinged to a central body, and may also include two locking arms.
The
clamps are closed when the free end of the clamping arm swings over and is
secured to the
central body or to the locking arm. A wedge is attached to each clamping arm
or locking
arm such that the wedge may be slid up and down when the clamp is in an open
position.
The clamping arm may be forked at its free end, allowing a portion of the
central body or the
locking arm to pass between the prongs of the forks when the clamp is closed.
To secure
the clamp in a closed position, the wedge is manoeuvred so that it is
perpendicular to the
axis of the clamping arm. Once this is done, the clamping arm cannot open
because its
path is blocked by the wedge.
In order to use this type of clamp, the clamping arm is closed and the wedge
simply
hammered into place. To allow for better manoeuverability in situations where
space is
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lacking, the wedge clamp may be designed to allow for the wedge to be hammered
home in
either direction, such that the end of the wedge is pointing to either end of
the pipe. This is
seen, for example, in Canadian Patent Nos. 533,916 and 571,181, both to Elly
Estie et al.
Canadian Patent No. 533,916 discloses two clamps attached to each other cross-
wise.
Each clamp is composed of a pronged clamping strap, and a clamping part. The
clamping
part has an eye which fits between the prongs of the clamping strap, and a
slotted wedge
which passes through the eye.
Canadian Patent No. 571,181 discloses two clamps attached to each other cross-
wise.
Each clamp is composed of a pronged clamping strap, and a clamping part. The
clamping
part has a hole through which passes a bolt having a T-head. Through the
bottom end of
the bolt is a slot through which passes a wedge. The bolt fits between the
prongs of the
clamping strap, and may be rotated so that the T-head is at 90° to the
prongs.
SUMMARY OF THE INVENTION
The invention relates to an improved two-way clamp for holding two pipes in
position
perpendicular to each other. The core of the clamp is a central body made from
a metal
such as cast iron. Two concavities are located one on each side of the central
body, offset
at 90° to each other. A semi-sphere-shaped socket features a wide slot,
and is located at
one end of each concavity.
Each clamp comprises a pivoting clamp arm and a locking arm. The pivoting
clamp arm is
hinged to the central body, at the opposite end of the concavity from the
socket. A locking
arm has a ball at one end and a narrow rectangular slot at the other end. The
ball is
permanently located inside the socket, as it is too wide to be removed via the
wide slot. This
ball and socket joint allows the locking arm to swivel. A wedge fits through
the narrow
rectangular slot. The wedge has a small bolt at its narrow end, which prevents
the wedge
from sliding out of the slot. The wide end of the wedge is wider than the
narrow rectangular
slot, which prevents the wedge from sliding out in the other direction.
The pivoting clamp arm and central body concavities may be lined with ridges
designed to
encircle the pipe, preventing it from slipping. The pivoting clamp arm is
equipped with two
notched prongs. When the locking arm is manipulated into the closed position
it fits
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between the prongs. The locking arm then swivels so that the wedge is oriented
perpendicularly to the pivoting clamp arm. Th wedge fits into the notches, and
when the
wedge is hammered down, the notches block any movement of the wedge towards
the
end of the prongs. Accordingly, when the wedge is fitted into to the notches,
the clamp
cannot open.
In a broad aspect, the present invention relates to a two-way clamp
comprising: a central
body having two 90° offset concavities and two semi-sphere shaped
sockets; two hinged
pivoting clamp arms attached to said central body; and two swivelling locking
arms each
having a ball-shaped end which fits into one of said sockets in the central
body, thereby to
define a pair of ball and socket joints on said central body and said locking
arms each
contain a slot through which fits a captive wedge.
Because the locking arm swivels via a ball and socket joint, the wedge may be
hammered
home in either direction (i.e. with the arrow end facing either end of the
pipe). The ball and
socket joint also allows for greater flexibility and ease in manipulating the
locking arm and
wedge prior to closing the clamp.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of the clamp in a closed position.
Figure 2 is a perspective view of the clamp in an opened position.
Figure 3 is a side view of the clamp in a closed position.
Figure 4 is a side view of the clamp in a closed position.
Figure 5 is a side view of the clamp in a closed position.
Figure 6 is a side view of the clamp in a closed position.
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Figure 7 is a top view of the clamp in a closed position.
Figure 8 is a bottom view of the clamp in a closed position.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to Figure 1, the central body (11) is a single iron casting with two
90° offset
concavities to accommodate scaffolding pipes. A semi-sphere-shaped socket (6)
is
located on one end of each concavity, said socket having a wide slot. Two cast
iron
pivoting clamp arms (7) are attached with hinges (10) to the central body (11
) at opposite
ends of the
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concavities from the sockets (6). Along the inside curve of the pivoting clamp
arms and
concavities ridges (9), knurls, or other gripping surface modifications may be
located. At the
end of each pivoting clamp arm are two prongs (12), each with a small notch
(8). A cast
iron locking arm (3) has a ball (5) on one end. The locking arm extends
through the socket
slot into the socket (6). The ball (5) is therefore permanently fixed inside
the socket, as said
socket slot is too narrow for the ball to slide through it. At the other end
of the locking arm
(3) is a narrow rectangular slot (4) into which fits a wedge (1 ). At the
narrow end (13) of the
wedge (1 ) is a small bolt (2) to prevent the wedge from slipping out of the
slot (4).
In order to close the clamp, the central body concavity (11 ) and pivoting
clamp arm (7) are
closed around a pipe. The wedge is pulled up so that the narrow end (13) of
the wedge (1)
is at the level of the slot (4). The locking arm (3) is then pulled through
the prongs (12) of
the pivoting clamp arm (7). The locking arm (3) is swivelled so that the wedge
(1 ) is
oriented at 90° to the pivoting clamp arm (7). To secure the clamp, the
wedge (1 ) is then
dropped down, and hammered into place as far as it will go. Once the wedge (1)
is in place,
it links the pivoting clamp arm (7) and the locking arm (3) together, so that
the clamp cannot
open. The wedge (1 ) is flush with the notches (8) and cannot slide past them.
The disclosed embodiment is simply a preferred embodiment; numerous
modifications may
be made without departing from the spirit of the invention. For example, the
clamp may be
made from other materials such as forged iron, steel, brass or bronze.
