Clamping Appliance for Frames with Glued Mitre Joints.
Year: 1898

page_text: Date of Application, 18th Apr., 1898-Accepted, 9th July, 1898
COMPLETE SPECIFICATION.
Clamping Appliance for Frames with Glued Mitre Joints.
I, BARTHEL MULLER, of 32, Friedrichstrasse, Coblenz, Germany, Artist, do
hereby declare the nature of this invention and in what manner the same is to be.
performed, to be particularly described and ascertained in and by the following
statement:
This invention relates to a clamping device for use in the manufacture of
picture and other frames having glued mitre joints whereby, on the fitting
together of the glue-coated mitre edges of the parts of the frame, these are
pressed together with a uniform and strong pressure by the mere turning of a
tightening lever.
I will describe the said invention with reference to the accompanying drawings,
in which Fig. 1 shews the complete apparatus as applied to a rectangular frame,
Figs. 2 and 3 shew a front view and section of one of the angle pieces to an
enlarged scale and Figs. 44 and 5 shew a front view, sectional plan and end view
of an angle piece with the tightening device applied thereto.
As shewn at Fig. 1, the clamping device consists of four rectangular angle
pieces ABCD, which are connected together by a cord k. As shewn at Figs 2
and 3, the angle pieces consist of an accurately rectangular shaped piece of
wood a strengthened by an iron plate b, which forms a groove e in combination
with the notched outer edge of the wood piece. Through this groove is passed a
cord which can slide therein and passes at the corner over a guide pulley f,
being prevented by pins d from falling out. The main feature of the clamping
device consists of a tightening mechanism applied to the angle piece I as
shewn at Figs. 4 4 and 5.
This angle piece D differs from the others in that instead of having a single
iron cheek b, it has two such, bb, between which is formed a wide groove c¹ that
serves to receive the tightening lever.h, pivotted on a pin i.
When the clamping device has been fitted upon a frame, as shewn by way of
example at Fig. 1, the angle piece 1) with the tightening device will be situated
at the upper right hand corner.
The cord has its one end which is tied into a knot, secured to the lever / by
being passed through a hole m therein and passes thence firstly over the grooved
and circularly curved end w of the lever and then over the roller r downwards,
and successively over the grooves and rollers of the angle pieces ABC and under
the pin n of piece 1) and finally back again to the lever end w. Here the
part is passed, in the contrary direction to its commencement ¹, round the lever
end w and through the hole p of the lever h, and after being twisted round the
projecting screw or stud s it is finally passed under the loop 9 of the spring
hook v, which is attached at a to the piece D and inserted into a hole in the lever,
the free end of the cord being allowed to hang down as shewn.
This clamping appliance is used as follows:
The parts of the frame cut with mitre ends after having their mitre surfaces

page_text: coated with glue, are fitted together and have the separate angle pieces A, B, C, D,
applied to the corners.
The tightening lever is then turned up (the loop q being withdrawn there-
from) so as to be about parallel with the mitre, to an angle of about 45°. The
end of the cord is then drawn tight by hand and secured tightly round the
screw.
The lever is then turned downward whereby the two parts and of the
cord will be wound up round the pulley-shaped end w of the lever hand thus
exert a strong pull upon the part of the cord extending round the angle
pieces A, B, C, D, which are in consequence pressed with considerable force and
great uniformity against the outer surfaces of the frame corners, by which means
any distortion of the frame is effectually avoided.
By means of the hook v, which can be conveniently attached by a screw to the
lower end of the angle piece D, as shewn, the lever is prevented from turning
back out of the tightening position, so that the frame can be secured under pres-
sure for any length of time by the said clamping device.
The loop 9 of the spring hook at the same time serves, as above described to
nip the end of the cord against the lever h, and thus prevent any loosening
thereof.
By means of the above described clamping device, therefore, it is rendered pos-
sible to draw together the freshly glued parts of a frame in such manner that all
the eight glued surfaces are pressed together in a perfectly uniform manner,
without the possibility of the frame being in any way damaged thereby, which
damage was practically unavoidable with the usual appliances for this purpose.
The appliance operates rapidly, reliably and conveniently and can be applied
to frames of any size.
Although, by way of example I have shewn the invention as applied to a
rectangular frame it will be obvious that it is equally applicable to any frames
composed of three four or more parts joined together by glued mitre edges, the
shape of the angle pieces being varied accordingly.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I
claim is:
Appliance for clamping together wood frames composed of three four or more
parts secured together by glued mitre edges, consisting of angle pieces such
as A, B, C, adapted to be applied to the corners of the frame, over which angle
pieces is passed a cord k preferably by the aid of guide rollers f, the ends of
the cord being passed over the short arm w of a tightening lever such as h
pivoted to the one angle piece, such as D), so that by turning the said lever the
cord is drawn tight over the angle pieces and is secured in that position by a
locking device such as qvæ applied to the lever so as to hold both this and the
end of the cord, substantially as described.
101
1000