Improved Method of and Apparatus for the Manufacture of Rasps.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improved Method of and Apparatus for the Manufacture of Rasps.
1, JOHN H. STOKES, of Freehold, in the County of Monmouth, State of New
Jersey, United States of America, Manufacturer, 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 the manufacture of rasps, heretofore it has been found
essential to make teeth by raising them from the surface of the blank by means of a
pivotally yielding punch, the cutting end of which penetrates the metal at an angle
to the face thereof, describing a circle to lift the metal out of the recess formed to
make the projecting tooth, and this movement of the point of the punch has been
found to be necessary, for if the punch entered the metal direct at the ordinary
angle at which the blank and punch are held relatively to each other an indentation
only in the metal would result.
I have found, however, by experiment, that by increasing the angle at which the
blank is held relatively to the punch and changing the form of the punch as herein-
after explained that the punch may have a positive downward movement into the
metal of the blank without any forward or pivotal movement of its penetrating end
as has been heretofore found necessary; this action making a recess, the walls of
which are practically at right angles meeting on a straight line at the bottom of
the recess, the teeth formed being in all particulars similar to those heretofore
formed by the old process.
In the old method, while the result was very satisfactory the means for producing
the result were objectionable in many particulars. In the old method it was
impossible to use a gang of punches as they could not be given the required
pivotal movement successfully on account of the unevenness of the blank surface
causing lack of uniformity in the action of the different punches of the gang and
resulting in imperfect work and breakage of the punches. Further than this the
condition of the punches affected the extent and time of the pivotally yielding action,
as a newly ground punch required but about half the movement to make a tooth,
as that needed by a slightly worn punch, and thus this was particularly fatal to the
use of a gang of punches for unless they all yielded at the same time so as to have
movement in unison and an equal movement, the result would be disastrous, and in
fact these objections have been so serious that practically it has been impossible to
These
use a gang of punches in the formation of the teeth by the old method.
objections have been attended with serious results in the use of a single punch as
the wear upon the punch was material; great care in the grinding of the punches
was necessary and even then the peculiar movement of the end of the punch rendered
it liable to break at any time.
By the present improvement I render unnecessary the use of the pivotally
Fielding punch holder and thus obviate the necessity for the peculiar movement of
the punch which materially lessens the wear, renders it possible to use a simple
form of punch which is easily made; obviates danger of breakage and enables me
to use a gang with perfect results for the reason that the movement of the gang is
uniform and positive and simply penetrates the metal on a straight line to form the
teeth.
In the accompanying drawings,
Fig. I represents a front elevation of the machine, partly in section.

page_text: Figs. VI and VII show forms of gang punches.
Fig. VIII is a detail view of the blank and punch made on a larger scale than
Figs. I and II.
A, represents the frame work which surrounds the reciprocating frame B, which
as shown in Fig. 111, is guided in its up and down movement in the said frame A
by means of ways. The frame A is arched at its upper end, as at 6 and bearings
are formed for a shaft c carrying a balance wheel 1 and band wheels 2.
A cam D
is centrally arranged on the shaft the cam and shaft moving in the direction of the
arrow. The frame B is depressed by the high part of the cam to give the punching
action and as soon as the shoulder of the cam has passed springs e, force the frame B
upward lifting the punch for another blow. These springs e, are adjusted to give
them the proper tension.
The frame B is made of rectangular form and within its side walls is located the
cylinder C carrying upon its lower end a projection 3 made very strong for the
purpose, to support the punch or gang. The punch or gang may be securely held
by a set screw or other suitable menus.
As the blanks are of varying thickness and as it is desirable to have the teeth of
uniform height I have aimed to provide a construction of apparatus which will
cause the teeth to be made uniform without regard to the irregularity of the
thickness of the metal of the blank and this is attained by providing a definite
determined movement of the punch by the action of the cam in relation to the
thickness of the blanks and the amount of resistance offered. Thus in the thinner
portions, the full movement of the punch is permitted and makes a tooth of the
determined height while in the thicker portions the punch will penetrate the metal
sufficiently to make a tooth of the same height but beyond this by reason of
the increased resistance the movement imparted by the com will be absorbed by a
spring interposed between the punch and the source of power which is adjusted to
act at a certain resistance. Without some means of taking up this surplus
movement it is apparent that in the thicker portions of the blank, teeth of greater
height would be formed and the teeth would thus vary according to the variations
in the thickness of the blank.
In carrying out this part of the invention I place within the cylinder C, a coiled
spring, and above the spring I place a disc threaded upon the stem in which is
swivelled at its upper end in the frame B. It will be seen that the blow delivered
by the cam D upon the frame B is transmitted to the tool through the stem m and
its disc and the spring y and cylinder C, but the spring is of such tension as to be
unyielding in its action.
In order to adjust the tension of the spring g, I provide a ratchet lever n upon
the stem m, which is provided with a feather o, the lever being held between the
projections p, extending from the frame. By the turning of this lever the tension
of the spring may be increased or diminished. In order to prevent any change in
the position of the cylinder C and the frame B by reason of such adjustment of
the spring I form a stop to prevent the upward movement of the frame B by means
of the shoulders, bearing against the lower edge of the cylinder C.
In order to very quickly throw the punch out of operation without stopping the
rest of the machinery I provide a slide on the upper end of the frame B which has
a handle u, and by means of this handle the slide may be withdrawn from under
the cam and thus rotation of the cam will be effected without action upon the
frame B.
In order to regulate the force of the blow I move the slide beneath the cam so
as to receive a full or partial action therefrom.
As I have beiore stated, I have found that by increasing the angle of the
inclination at which the table supporting the blank is held relatively to the line of
the punch, the pivotally yielding movement of the punch is not required and the
punch or gang may be rigidly held in the end of the tool support and descend
positively in a straight line upon the blank. The approximate inclination is shown
in Figs. II and VIII. This change in the inclination and in the method of raising

page_text: the tooth necessitates a change in the punch, as the action is that of a direct punch
instead of a combined punch and lift as heretofore and enables me to use a punch
of simple form. This is shown in Fig. VIII and in gang form in Figs. VI and VII.
The rear line of the punch is centrally on the body and the side walls extend at
right angles to each other towards the front, the shape of the punch in section being
approximately square or diamond shaped. The lower end is cut on a slant, the
lowest point being directly at the centre of the extremity of the rear central line
and the slant is upward from this line to the front. In Figs. VI and VIII show
two forms of gang punches. While a series of single punches may be used together,
they are so small and require to be so accurately adjusted in relation to each other,
that I find a great advantage in making the gang in one piece as they can thus be
handled as a single punch and sharpened as a single punch requiring no independent
adjustment.
In Fig. VI the rear working face is shown at a¹ formed with a strengthening
piece bserving also as the holding shank, the end being cut on a slant from the
rear upwardly to the front, leaving a series of projecting punch points c' or the
blank & may be made with projections a' on each face as in Fig. VII.
The inclined table 4 supports a holder 5 for the blank, and this holder is moved
downwardly step by step equal to the distance between the rows of teeth by
means of a feed movement, consisting of the screw 6 turned by pawl and ratchet
mechanism 7 operated from the source of power aud this screw is engaged by a
threaded lever 8 connected to the holder 5. The holder is moved downward against
the pressure of a spring or weight 9 connected to the holder which returns the
holder to normal position when the lever 8 is disengaged from the screw 6.
The teeth are made in the blank with alternate lateral rows in alignment and I
provide for the shifting of the blank to effect this. The blank 10 is secured to a
channeled plate 11 which in turn is held within a second channeled plate 12
which is within the holder proper. The holder has one side open and this is
closed by a projection 13 from the table, which projection is recessed on its
inner face and in this recess is inserted a plate 14 having a toothed or serrated
face. The plate 12 is kept pressed against the projecting wall 13 of the table
by springs 15 between it and the wall 16 of the table. The right hand side
of the plate 12 has projecting V shaped pieces 17 fitting the like serrations
in the inserted piece and the action of the feed movement forcing the holder
downward step by step, (this movement being equal to one half the distance
between the apex of the teeth on the inserted piece,) moves the V shaped
pieces 17 over the teeth of the inserted piece which shifts the plate 13 and the
blank carried thereby to the left and the apex of the piece 17 bears on the apex of
one of the teeth of the inserted piece. A punching operation immediately follows
while the blank is thus held and as soon as the punch is withdrawn the feed
operates and the springs force the V shaped pieces down into the notch after which
another punching operation follows and so on the plate 12 being thus shifted back
and forth after each feed of the table so that the teeth are punched alternate in
position. In order to vary the amount of this shifting movement the inserted piece
may be made removable and interchangeable pieces provided with finer or coarser
teeth or serrations. A handle 18 is provided to throw back the plate 12 when it
is desired to change the inserted piece.
While I have shown the table inclined and the punch arranged vertically the
table may be horizontal and the punch inclined without departing from the spirit
of my invention.
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 hereinbefore described method of forming rasps which consists in forcing
the punch directly into the blank both blank and nunch being held sœainst »ivotal

page_text: 2. In combination, a punch having its lower end formed slanting and with its
rear walls extending approximately at right angles to each other and meeting at
the rear on a straight line and a blank supported at an acute angle to the said
punch and means for operating the punch, substantially as described.
3. In combination, a punch in gang form having its lower end inclined upwardly.
from the rear and its rear face grooved to form a series of punching projections at
the lower end, substantially as described.
4. In combination, a punch in gang form having its lower end inclined upwardly
from the rear and a series of V shaped grooves in the rear face of the punch
forming a series of punching projections, substantially as described.
5. In combination with a tool, a vertically moveable frame with means for
applying pressure to the same for the punching operation and a spring interposed
between said tool and the source of power, substantially as described.
6. In combination with a tool a vertically moving frame, means for applying
pressure to the said frame and a spring interposed between the tool and the frame,
substantially as described.
7. In combination with a punch and mechanism for operating it, a table for
supporting the blank, a holder between the blank and table the blank being movably
supported within the holder and means for shifting the blanks laterally, substantially
as described.
8. In combination with a punch and mechanism for operating it, a table for the
blank, a holder with means for moving it, a blank movably supported by said
holder, and a pattern device between the blank support and the table for shifting
the blank laterally in relation to the punch, substantially as described.
Dated this 22nd day of April 1892.
SLOAN & LLOYD BARNES,
Castle Chambers, 26, Castle Street, Liverpool, Agents for the Applicant.