Improvements in Mitre Cramps.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Mitre Cramps.
I, THOMAS HUGHES, of No. 24, Florence Street, Newcastle-under-Lyme, in
the County of Stafford, Roll Turner, do hereby declare the nature of this inven-
tion to be as follows:
-
The objects of my invention are:-
To secure a more effective grip of the work, to force the mitres together at the
joint in a direction tending to close it perfectly instead of, as in ordinary cramps
to open it at the inner angle; and provide for the adjustment of the cramp upon
the bench, on which it may be fixed, to a horizontal or vertical position or at any
angle and there to secure it.
The cramp is operated by revolving a central fixed screw, preferably with square
threads, thereby traversing upon it a nut suitably guided in either direction.
This nut may have, either formed upon it or suitably fitted on each side, bearings
for vertical pins having preferably formed solid upon their upper ends, wheels
with serrated teeth and keyed or otherwise secured, upon their lower ends
toothed pinions. Between these pinions is a rack into the teeth of which those
of the pinions engage and the operation is as follows:-
The mitred frames or mouldings being placed in the cramp against a "fence"
and the screw being revolved so as to traverse the nut forward, the two toothed
pinions revolve as they also travel forward, by the action of the toothed rack, and
thus revolve the wheels with serrated teeth in opposite directions the teeth gradu-
ally biting into the rebates of the frame or moulding and forcing the mitres
closely together in a direct line instead of, as in ordinary cramps, tending to
open the joint at its inner angle.
The cramp rests upon the bench on three feet, of which the two front ones will
be hinged in fixed brackets in which they can be turned to any convenient angle
between the horizontal and vertical positions, and secured by a winged jam screw
when required. as when the frames or mouldings are being nailed."
"
The fence" will be of the ordinary kind for mitre cramps except in very
large work when I propose to provide for any possible springing of the frames or
mouldings between the extreme corners of the fence.
DL:
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page_text: Improvements in Mitre Cramps.
I, THOMAS HUGHES, of No. 24, Florence Street, Newcastle-under-Lyme, in
the County of Stafford, Roll Turner, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:-
The objects of my invention are:-
To secure a more effective grip of the work, to force the mitres together at the
joint in a direction tending to close it perfectly, instead of, as in ordinary cramps,
to open it at the inner angle, and provide for the adjustment of the cramp upon
the berch, on which it may be fixed, to a horizontal or vertical position or at any
angle and there to secure it.
The cramp is operated by revolving a central fixed screw, preferably with square
threads, thereby traversing upon it a nut suitably guided in either direction. This
nut may have, either formed upon it or suitably fitted on each side bearings for
vertical pins having preferably formed solid upon their upper ends wheels with
serrated teeth and keyed or otherwise secured, upon their lower ends, toothed
pinions. Between these two pinions is a rack into the teeth of which those of the
pinions engage and the operation is as follows:-
:-
The mitred frames or mouldings being placed in the cramp against a
"
fence"
and the screw being revolved so as to traverse the nut forward, the two toothed
pinions revolve as they also travel forward, by the action of the toothed rack, and
thus revolve the wheels with serrated teeth in opposite directions the teeth
gradually biting into the "rebates" of the frame or moulding and forcing the
mitres closely together in a direct line instead of, as in ordinary cramps, tending
to open the joint at its inner angle.
The cramp rests upon the bench on three feet of which the two front ones will
be hinged in fixed brackets in which they can be turned to any convenient angle
between the horizontal and vertical positions and secured by a winged "jam"
screw when required, as when the frames or mouldings are to be nailed.
6.
"
The fence will be of the ordinary kind for mitre cramps except in any large
work when I propose to provide for any possible springing of the frames or mould-
ings between the extreme corners of the fence.
DESCRIPTION OF DRAWINGS.
Fig. 1 is a plan, Fig. 2 a section through the line AB and Fig. 3 a section
through the line CD of Fig. 1.
The cramp is operated by revolving a central fixed screw A thereby traversing
upon it a nut B which nut has formed upon each side bearings for vertical pins Ŭ
having formed solid upon their upper ends wheels 1) with serrated teeth and upon
their lower ends toothed pinions E, between these two pinions is a rack F into the
teeth of which those of the pinions engage. The operation is as follows:-
The mitred frames or mouldings being placed in the cramp against the fences
and the screw A being revolved so as to traverse the nut B forward, the two
toothed pinions E revolve as they also travel forward, by the action of the toothed
rack and thus revolve the wheels D in opposite directions the serrated teeth
gradually biting into the frame or moulding and forcing the mitres closely
together in a direct line instead of, as in ordinary cramps, tending to open the
joint at its inner angle.
The cramp rests upon the bench on three feet J of which the two front ones will
be hinged in fixed brackets G in which they can be turned to any convenient

page_text: angle between the horizontal and vertical positions and secured by a winged
"jam" screw H when required, as when the frames are to be nailed.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed that what I claim is:-
1. The improvements in mitre cramps described and illustrated having a fixed
central revolving screw rotating a pair of serrated wheels and a pair of toothed
pinions engaging in a rack. The screw being revolved the serrated wheels
advance towards the frames or mouldings and coming in contact force same
tightly together.
2. The construction, arrangement and combination of parts substantially as
described and shewn on the drawings.
Did thin 7th day of Wah………………… 1900
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.