Improvements relating to Clamps for Fret-saw Frames.
Year: 1897

page_text: Date of Application, 19th July, 1897-Accepted, 28th Aug., 1897
COMPLETE SPECIFICATION.
Improvements relating to Clamps for Fret-saw Frames.
We, HOBBIES LIMITED, of 12 Paternoster Square, in the City of London, and
HERBERT JEWSON, of East Dereham, in the County of Norfolk, Engineer, 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 clamp for fret-saw frames whereby tension can be readily
put on the saw or be as readily removed therefrom and which is so constructed and
fitted that when the tension is adjusted the saw moves in a practically straight line.
The clamp is applicable to either hand or machine frames, and is of a simple character
and comparatively inexpensive.
In the accompanying drawings Fig. 1 is a side elevation of an ordinary hand fret-
saw frame fitted with a clamp according to this invention, and Fig. 2 is part of a
front elevation of same; Fig. 3 is a perspective view of part of the clamp. Fig. 4 is
a side elevation of the top arm of a machine frame fitted with a clamp according
to this invention.
In the form shown in Figs. 1 to 3 the front end of the upper arm A of the frame
is provided with an aperture B in which is loosely fitted a pillar or stem C to
the upper end of which is pivotted at D a cam lever E having cheeks e which bear
on the upper arm A of the frame and on each side of the aperture B, as shown in
Fig. 2. The lower end of the pillar or stem C carries a clamping screw device F of
the ordinary character.
To fix the saw in the frame and put the tension thereon the cam lever E is
raised into the position shown by the dotted lines in Fig. 1. The ends of the saw
are then secured in the clamping screws F and G in the ordinary way, and the
arm E of the cam lever E is pressed down until it has rotated about its centre D
through about a right angle and rests on the upper arm A of the frame in the
position shown by the full lines in Fig. 1. By this rotation the cheeks e of the
cam lever E have been pressed on the upper arm A of the frame and have
thus raised the centre D until the highest part is reached when the cam rests
with the points e¹ of the cheeks e on the arm A of the frame as shown in
Fig. 1.
The aperture B is made just sufficiently large to allow the requisite play to the
pillar or stem C and serves to guide the latter which is thus constrained to move
in a practically straight path.
The form shown in Fig. 4 differs only from that already described in having a
plate H which is rigidly secured to the arin A of the machine frame and is furnished
with an aperture B through which passes the pillar or stem C fitted and operating
as before described.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is :-
A clamp for fret-saw frames consisting of a pillar or stem passing through an

page_text: aperture in the upper arm of the frame, or in a plate secured to said upper arm, said
pillar or stem having a clamping screw at the lower end and a cam lever pivotted
on or to its upper end combined and arranged to operate substantially in the manner
and for the purpose herein before. described and illustrated in; the- accompanying
drawings.
Dated this 19th day of July 1897.
F. W.
GOLBY,
36 Chancery Lane, London, W.C., Patent Agent for the Applicants.