Improvements in Machinery for Cutting the Teeth of Rasps.
Year: 1899

page_text: Date of Application, 9th May, 1899
Complete Specification Left, 9th Mar., 1900-Accepted, 14th Apr., 1900
PROVISIONAL SPECIFICATION.
Improvements in Machinery for Cutting the Teeth of Rasps.
We, THOMAS PORTER LOCKWOOD, Managing Director of Lockwood Brothers
Limited, Spital Hill Works, and FREDERICK POTTS, of the same address, File
Manager, both in the City of Sheffield, do hereby declare the nature of our
invention to be as follows:-
Our invention relates to improvements in machinery for cutting the teeth of
horse rasps and like rasps.
The object of the invention is to produce a transverse row of teeth at each blow
of the cutters, and also to vary the position of each of a series of such rows trans-
versely, up to six such rows or thereabouts, such varied series being repeated
until the cutting is completed.
To accomplish this we make the holder which carries the cutters, capable of
sliding horizontally in the vertically moving ram of the machine, transversely or
across the bed upon which the rasp is laid, or in some cases the holder may move
upon a pivot as the required movement or travel is very little.
The cutter holder is constructed to hold a set of cutters or chisels, say half a
dozen for example which are secured by a set screw or other equivalent device;
such set of cutters representing one row of teeth.
The transverse movement of the cutter holder is obtained by means of an
adjustable tappit carried by the holder, and provided with an antifriction roller
which is in contact with a cam having differential faces, and which is caused to
rotate at the desired speed intermittently each face causing the chisel holder to
alter its position.
The holder is drawn back and kept to the face of the cam by a spring or
weight.
We prefer to drive the machine by means of a double throw cam acting upon
the long end of a pivotted lever, the short end of which raises the ram or slide
carrying the cutters.
A smaller double throw cam upon the same shaft operates the feed motion, and
the teeth spacing cam before described intermittently.
The rasp is carried upon a travelling bed in the usual manner, motion being
imparted by a screw and clasping nut driven by the feed motion.
A hand lever with catch is provided by which the ram or slide can be caught
and sustained to enable the cutters to be removed for any purpose.
The weight of the travelling bed is counterbalanced by a chain and weight,
passed over a pulley at the top of the fixed bed.
The presser is pivotted in front of the cutters and can be raised by the foot as
required.
The frame of the machine may be of any suitable construction.
Dat the 1et dar of Var 1899
ROBT. F. DRURY, C.P.A.,
Agent for Applicants,
Bank Buildings, George Street, Sheffield.

page_text: Improvements in Machinery for Cutting the Teeth of Rasps.
We, THOMAS PORTER LOCKWOOD, Managing Director of Lockwood Brothers
Limited, Spital Hill Works, and FREDERICK POTTS, of the same address, File
Manager, both in the City of Sheffield, 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:
Our invention relates to improvements in machinery for cutting the teeth of
horse rasps and similar rasps.
The object of the invention is to produce a transverse row of teeth at each stroke
or blow of the cutter or cutters; and also to vary the position of each row in
series of six rows or thereabouts, such series of rows being repeated until the
cutting of the rasp is completed..
The annexed drawings represent a machine with our invention applied to
its construction, like letters of reference refer to like parts in all the several
views.
Fig. 1, elevation of rasp cutting machine with top part of usual construction
removed.
Fig. 2, side elevation of same.
Fig. 3, plan of machine.
Fig. 4, elevation of cam movement to cutter.
Fig. 5, plan of same.
Referring to the annexed drawings. A is the body or standard, B is the slide,
C the travelling bed on which the file or rasp is laid, D the feed screw, E the nut
box, F the tup, G diving pullies, H the presser for holding the rasp upon the
bed, I the weight and chain for drawing up the travelling bed C, J is the cutter
holder which slides within the tup, i the cutters, L the cam which presses down
the lever M, and raises the tup, N is a pin or roller which engages with the end
of the lever, O is the feed motion operating the screw D, and the spacing cam P';
Qis an adjustable tappit connected with the cutter holder J, R is a stud carrying
a coiled spring S which draws back the cutter holder.
In order to accomplish the object of the invention which as mentioned before
is to cut a transverse row of teeth at each blow and to vary the position of such
rows upon the rasp, we construct the holder J, which carries the cutter or
cutters K. capable of being moved horizontally in the tup to and from the body
of the machine, and across the rasp transversely or as the required movement
is so small we may obtain an equivalent movement by causing the holder to be
turned upon a pivot placed at some distance from the back of the cutters, but we
prefer the former method.
The cutter holder is constructed to hold either a single cutter having a series
of cutting points, or a set of separate cutters as may be found most economical,
or best adapted to the work.
The transverse movement of the cutter holder J, is obtained by means of an
adjustable tappit Q, carried by the holder, and preferably provided with an
antifriction roller which is brought into contact with a differential-faced cam P,
fixed upon a revolving shaft T.
This cam is caused to rotate intermittently and as each face engages with the
tappit, the holder and cutters are moved to a different position over the face of
the rasp.
A coiled spring S,, carried by a stud R, and also secured to the cutter holder,
draws back the holder and keeps it in contact with the faces of the cam.
We operate the tup F, by means of a double throw cam L, carried upon the

page_text: driving shaft U, which presses down the long end of a pivotted lever M, the
short end of which passes under a pin or roller N, in the tup and raises it until
it reaches its highest point when it drops and by its gravity and the reaction of
one or more springs gives the desired blow and cuts the teeth.
A smaller double throw cam V, simultaneously operates the intermittent feed
motion connected with the screw D, moving the travelling bed with the rasp
(while the tup is rising) to the requisite distance for the next row of teeth; the
spacing cam P, is also turned to bring another face against the tappit, forcing the
cutter holder forward, or permitting the spring to draw it back, as the case may
be
The rasp is carried upon a travelling bed, such as C, in the usual manner,
provided with a feed screw D, releasing nut E, presser H, and weight and chain I,
for drawing back the bed to the desired position.
W is a hand lever with a projection to enter a slot in the side of the tup and
so to retain it when at the top of its stroke or thereabouts to enable the cutters
to be replaced or for other purposes.
The standard A of the machine may be varied in form, and equivalent means
may be substituted for any of the described parts which are common to machines
for cutting the teeth of files and rasps, and which we do not claim as forming
part of our invention.
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:-
-
1-A machine for cutting a transverse row of teeth upon rasps at one blow
of the cutter, and for varying the relative position of each alternate row, con-
structed substantially as herein before described and shown.
2--In a machine for cutting a transverse row of teeth upon rasps at one blow,
a horizontally sliding cutter-holder held in the lower face of the tup F, provided
with a suitable cutter or cutters, in connection with and operated by a cam l',
rotated intermittently, and having a number of differential faces by which the
cutter holder is moved to different positions, and drawn back by a spring $, or
equivalent means, as herein before described and shown in the drawings.
3--In a machine for cutting the teeth of rasps, a sliding cutter holder, capable
of being moved in or upon the tup transversely across the rasp by a suitable
intermittent movement so as to cut each alternate row of teeth in a different
position to the preceding row as herein before described.
Dated the 8th day of March 1900.
ROBT. F. DRURY, C.P.A.,
Agent for Applicants.