IMPROVEMENTS IN CARINET-MAKERS' HAND CLAMPS
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by George Whight at the Office
of the Commissioners of Patents, with his Petition, on the 19th
August 1871.-A communication from abroad by Abiel O'Dell, of
Toronto, Canada.
I, GEORGE WHIGHT, of the Firm of Whight & Mann, of Gipping
Works, Ipswich, in the County of Suffolk, Machine Manufacturers; do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
CARINET-MAKERS' HAND CLAMPS," a communication, to be as follows:-
My Invention relates to a hand clamp chiefly designed to be used by
cabinet-makers and others for holding pieces of wood while being glued
or otherwise joined or fastened together, and which may also be used for
metal work of various kinds. The hand clamps heretofore commonly
used for such purpose consist of two parallel pieces or jaws connected
together at each end by a screw, and by turning these screws the clamp
is adjusted to hold or release any object placed within it. But clamps
so constructed are in some cases difficult to fasten and unfasten, and
occupy much time in adjustment. The handles of the screws have to be

page_text: grasped and turned with great force, and frequently produce blisters on
the hands of the operator, and as these handles do not permit the power
applied to them to be advantageously exerted, it is impossible to
produce a very great pressure upon the object held by the clamp.
I obviate these difficulties in the following manner:-I construct my 6
improved hand clamp with two parallel pieces or jaws of wood or
metal and of suitable size, and pass an adjusting screw through them
at one end of the clamp. This screw is kept in place by a tangent pin
which fits in a groove formed around the screw. At the other end of
the said clamp there is another screw_ passed through one of the jaws 1
which I will call the bottom jaw. The end of this screw that projects
through the said' jaw and bears against the other or top jaw, is provided
with a metal cap or thimble. The top jaw is provided with an excentric
which is placed in a slot in the said jaw immediately in front of the
metal cap of the screw. This excentric is fitted to turn on a pin passed 1
through the sides of the slot and has a lever or handle whereby it can
be turned on the said pin. The said excentric is arranged at the back
end of the clamp, whose jaws of the other end are extended far enough
beyond the adjusting screw to grasp and hold any object conveniently
and securely. Between the two screws but nearest to the one at the 2
back of the clamp, I place a guide rod or bar which is pivotted in one
jaw and extends through a slot in the other. This guide bar keeps the
two jaws in the proper relative position while the pivot prevents its
offering any obstruction to the free adjustment of the said jaws.
"
In adjusting the clamp it is placed in the ordinary manner upon the 2
pieces of wood or other material to be fastened together, the screws
being used to adjust it so that it will take the said pieces freely between
its jaws. Then by means of its lever the excentric is turned and forced
against the metal end of the back screw. The adjusting screw at the
front end of the clamp has a shoulder which bears against the outside
of the top jaw, and this shoulder forms a fulcrum for the said jaw, so that
when the excentric is forced against the back screw the jaws, will be.
closed forcibly upon any object placed between them..
'The aforesaid clamp is adjustable to any required size within certain
limits; but if it is preferred to use a number of clamps of different sizes
each being capable of taking only one size, I dispense altogether with
the screws. I connect the jaws to each other by means of a jointed
bolt near the front end of the clamp, and place the excentric in a slot
.

page_text: in one jaw at the other end, the said excentric being arranged to bear
upon the inside of the other jaw. I place a small guide pin about
midway between the two ends of the clamp. In this modification of
my Invention the clamp is adjusted solely by means of the excentric.