Improvements in Saw Frames.
Year: 1893

page_text: Date of Application, 14th Feb., 1893-Accepted, 13th May, 1893
COMPLETE SPECIFICATION.
Improvements in Saw Frames.
1, JULES GELARDIN of 159 Rue du Temple, Paris, in the Republic of France
Ironmonger do hereby declare the nature of my said 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 for improvements in saw frames has for its object to provide
improved arrangements for clamping and for imparting the necessary tension to the
saw blades in which the ordinary screws, which wear away rapidly and which are
inconvenient to use are dispensed with and consists of a conical split clamp for
holding the upper end of the saw blade, of a wedge clamp for securing the lower
end of the saw blade, and of a lever tension arrangement for imparting the necessary
tension to the saw blades.
In the accompanying sheet of illustrative drawings:-
Fig. 1 is a view of a saw frame showing the saw in tension.
Figs. 2 and 3 are views of the lever tension arrangement showing the parts in
their two extreme positions.
Fig. 4 is a view of the frame handle, showing a modified arrangement of lever
tension apparatus.
Figs. 5 and 6 are similar views to Figs. 2 and 3 showing the modified arrange-
ment of lever tension apparatus.
Fig. 7 shows a modified arrangement of guide for the tension apparatus.
Fig. 8 is a view of the conical split clamp.
The saw frame consists of the main frame c of round, square or flat iron or steel
rod in one or more parts according to the shape or the quality of the material used,
which is prolonged and suitably bent to form the handle C₁ C" of the saw frame.
The iron or steel rod may be hammered at the corners D and E or over its entire
surface to give it greater rigidity, or if it is of steel it may be tempered.
At the top of the handle is a cross bar bb, bored with three holes, the outer ones
corresponding to the arms C' C", whilst the third, made in the centre, is square
and serves as a guide for the sliding jaw G, which is thus free to move in the
direction of the tension, but is prevented from twisting the saw blade. The lower
end of the saw blade is fixed to the jaw G (Figs. 1 and 4) bored at the end with a
cylindrical hole to receive the end of the saw blade which is fixed in and held by a
wedge pin O passing through it at right angles.
This method of attachment is only applicable for narrow blades; for wider ones
this hole is replaced at the end by a longitudinal slit as in Fig. 4 to receive the end
of the saw which is clamped by a pin O passing through a hole and pressing the
blade tightly against the side of the slit. This arrangement is then applicable to
blades of any width.
The clamping of the top of the saw-blade is effected as follows:-The end of the
frame (Figs. 1 and 8) terminates at A in a screwed conical clamp which is formed
in two parts by means of a longitudinal slit extending to F, so that one of the parts
can be completely detached from the other. The width of this slit is regulated
by the wing nut 4, which on account of the conical shape insure the clamping
of the saw blade.
The lever tension arrangement consists of three levers P, R, M, the adjacent
extremities 1, 2 & 3 of which are jointed to a small block K which is operated by
the lever M passing through the block at the point 2. The block is displaced
round the point 3, which is the extremity of the arm R. The other end of the
arm R is fixed to the handle at 5, whilst the other end 4 of the arm P is connected
to the piece G, revolving about its point of attachment. The result is that in

page_text: bringing up the lever M as in Fig. 2 the point 1 is lowered below the point 3,
bringing together the points 4 and 5, and putting the desired tension on the saw
blade. The position of these points and the method of attaching the levers to the
handle can be varied without departing from the nature of this invention.
Thus the arrangement represented on Fig. 4 is composed of a single arm P, the
arm R being suppressed. The block K is supported on the axis 8, on which it
can be rotated, the said axis being rigidly connected to the two sides C' C" of the
handle.
The displacement of the point 1, on which depends the tension, is therefore
obtained by the movement of the lever M, that is to say by the same principle as
in the first described arrangement.
The saw frame can be constructed in any suitable shapes and the cross piece bb,
which is provided at its centre with a square hole, may be replaced by the
eyelet (Fig. 7) formed by bending round a square mandril the end of the side
piece of the handle. This eyelet consequently effects the same purpose as the
cross piece, guiding the piece G, which runs' therein corresponding to the direction
of the tension and preventing it from giving any twist to the saw blade.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The conical split clamp for holding the ends of saw blades constructed
substantially as described.
2. The wedge clamps for holding the ends of saw blades in which a wedge or
conical pin bearing on one side of the blade presses it firmly against a rigid surface
on the other side, substantially as described.
3. The arrangement for imparting the desired tension to the saw blades,
substantially as described.
4. The improvements in saw frames substantially as described with reference to
the drawings.
-
Dated this 14th day of February 1893.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.