Leather Skiving Machine.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Leather Skiving Machine.
EDWIN E. BARTLETT 364 Atlantic Avenue Boston Mass., U.S.A. do hereby
declare the nature of this invention to be as follows:-
A leather skiving machine, consisting of a series of top rolls, and a bottom roll
or cylinder the bottom roll being larger than the top rolls, but the shafts
supporting and carrying the top and bottom rolls are so geared together, that the
periphery of the top and bottom rolls shall travel at the same speed but in opposite
directions.
The top rolls are to be so arranged and constructed that when a piece of
leather passes over the bottom roll, and under the top rolls, the top rolls shall
raise the thickness of the leather, and allow it to pass.
A knife the bottom surface of which is parallel with the bottom of the machine
so supported and arranged as to be adjusted to different angles from the line made
by the face of the bottom roll or cylinder, and a guard or spring over the botton:
roll, the said guard or spring being cut out to allow the top rolls to come down and
touch the bottom roll.
The purpose of the spring or guard is to feed the leather, after it has left the
top rolls and before it gets to the cutting edge of the knife by means of pressing the
leather down on the surface of the bottom roll which is made to revolve by
power.
Dated this Seventh day of May 1896.
EDWIN E. BARTLETT.
EDWIN E. BARTLETT Machinist 364 Atlantic Avenue Boston Mass. U.S.A.
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 machines for skiving leather or other similar material,
the essential features of which consist, first, in disposing the cutting-knife upon a
long swinging arm, whereby a change in the position of the knife vertically, either in
raising or lowering it to accommodate leather of varying thickness, will produce
a minimum movement laterally in either direction of the knife with respect to the
periphery of the lower feed roll or bed. Furthermore, in securing the knife to a
stock placed in the end of the swinging arm, said stock being capable of partial
rotation, to allow alteration in the angle of the knife in skiving, the axis of such
rotation being in alignment with the inner vertical face of the lower feed roll or
bed; hence change of angle in the knife does not alter its lowest cutting point
with respect to the circular bed-a very important feature; secondly in having the
cutting edge of the knife so adjusted upon the lower feed roll or bed as to meet a

page_text: vertical plane drawn through the centre of said bed at right angles to its rotation;
thirdly, in so disposing the spring presser-foot and the top feed rolls with reference
to the guide-plate that the said feed rolls shall extend through said presser foot and
engage and press the material upon the bed and thereby induce proper feed
motion; fourthly, in the general arrangement and disposition of parts, to be
hereinafter more fully described.
The drawings accompanying this specification represent, in Figure 1, a front
elevation, and Fig. 2, a plan of a leather skiving machine, embodying my invention.
Fig. 3, is an end elevation with the support P sectioned and the front portion
removed. Fig. 4, is a plan of the presser foot with the upper feed rolls removed.
Fig. 5 is a cross section through the rotary knife block ou line ¹¹ of Fig. 2.
Fig. 6 will illustrate a modification of Fig. 5.
In the drawings, A represents a standard, of which B is the base and Ca
vertical rib formed thereon. The latter is bored its entire length to receive the
shaft D, which is mounted in suitable bearings furnished at one end with the
corrugated lower feed roll or cylindrical bed E, with which the cutter co-operates
when skiving material. The other and opposite end is provided with a spur
gear F, which meshes with a similar but smaller gear G, fitted upon the
shaft H.
Upon the rib C, at a point near the gears F G, I have formed a
boss or
support C', for the arm or head 1, which extends parallel with but above the rib C.
This head is securely bolted to flanges cast on C, and becomes an integral portion
thereof. The head I, is also bored longitudinally and provided with a shaft, H, to
which, as before mentioned, is affixed the gear G, the two shafts D H, being
parallel and in vertical alignment one with the other. Moreover, the rear
extremity of the shaft H is provided with a driving pulley, J, by which motion is
transmitted to the entire operative mechanism of the machine.
In the front end of the head 1, I have formed a slot, a, to contain a movable spring
adjusted box, b, in which the front end of the shaft H revolves. Movement of
the screw c, raises or depresses this shaft H, and with it the upper feed rolls, d d²,
which are roughened or furnished with blunt teeth and mounted thereon. This
adjusting mechanism is to adapt the rolls to feed material of various thicknesses.
To the under side and upon the end portions of the head I, I have bolted a flat
spring or presser foot, e, which extends over the top of the circular bed E, but to
one side of it, and with the front edge, or that adjacent to the cutting edge of the
knife, coincident with a plane drawn vertically through the centre of the bed E.
The cutting edge of the knife is adjusted close up to this edge to prevent the
material from lifting while being operated on, as the spring e retains it closely to
the bed E, and acts as a presser-foot to maintain the leather upon the bed E.
I have, moreover, fornied an opening, f, to admit not only the feed roll d below
upon the bed E, but also to permit the guide plate g to project upward above the
top periphery of the bed E and the feed roll d. The spring e is further provided
with a second opening or slot, f³, adapted to admit of a second feed roll, d, upon
the extreme outer end of the shaft H, in order to facilitate the feed. I have
found in practice that the extreme outer end of the presser-foot or spring e, has a
tendency to rise, and after continued use to lose its power, when the material will
fail to be properly fed, one edge (the inner) advancing more rapidly than the
outer.
To obviate this difficulty I have constructed a support P, in alignment with the
head 1, and forming a continuation thereof. This support extends above the
presser-foot, and is provided with a downwardly projecting arm, Q, centrally bored
at R. This borc receives and contains a spring actuated stud, S, which bears and
rests upon the extremity of said presser-foot e, the amount of pressure upon the
latter being adjusted by means of the screw T. By this arrangement the presser
foot bears equally at all times upon the upper surface of the rotary bed E, and
the travel of the material across its face in the process of skiving is the saine at
all points.

page_text: The guide plate g¹ is shown as bolted to the top of C, and is adjusted closely to
the rear vertical face of the bed E, and provided with a horizontal step h. This
latter is flush with the top point or extreme upper portion of the periphery
of the bed E. The upper feed roll d laps the point between the bed É
and plate g, and the material fed to the machine has no tendency to crowd
and jam between the bed and guide plate, as it is supported by the step h, before
mentioned. Upon the rear of the head I. I have disposed and pivoted at i, a
swinging arm, K, cast with an offset, upon which is disposed a cylindrical arm or
bracket, L, holding the adjustable head stock and its cutting knife M. To permit
raising of the knife relatively to the periphery of the bed E, in order to operate
upon thick or thin material, I have formed a bracket, j, into which the arm K
slides, while the movement of the latter is effected by the adjusting thumb-
screw, k, located upon the bracket. A second screw, l, to be used as a check, is
disposed in the bracket and locks the arm in position after proper adjustment.
To effect alteration in the angle of the knife M relatively to the periphery of
the bed E, in order to change the slope of the angle given to the material in
skiving, I have perforated the arm L, longitudinally with a bore m, at right angles
to the shafts DH, and, further pierced it with a radial slot, n, which extends its
entire length and opens into the bore m.
Within the latter is fitted a short cylindrical stock, N, slotted at o its entire
length the width of this slot being just equal to the thickness of the knife M,
which latter is secured to its stock N by the screw p. It will, be observed that
the knife projects beyond the axis of the knife-stock, in which it is secured, but
since it becomes necessary to change the angle of the knife the radial slot, n,
before mentioned, is formed, which enables free rotation of the knife and its stock
in the arm L, to thereby provide for any suitable angle for skiving. When properly
adjusted to the desired angle, the thumb-screw q, secures the whole rigidly in place.
The arm L is pierced its entire length. Thus, in case the knife requires to be
taken out and sharpened, the screw p is relaxed and the knife slipped out at the
rear. The knife stock N is not altered or moved, but remains rigid, and the knife
can be reinserted and work recominenced without any further adjustment. To
prevent end play of the knife-stock N, two pins, st, are inserted, which bear
against each end of the support L. The rear one I have made of considerable
length, to be used as a lever, by which to readily turn the stock N in its bearings
after raising the check screw g when adjustment in the angle of the knife is
required. The centre rotation of the knife stock N, and its knife M is in
alignment vertically with the edge r of the guide plate g, (see Fig. 2) hence any
change in the angular position of the knife does not alter its position laterally of
the guide plate, and no farther adjustment is required a very important feature in
machines of this class.
The centre of rotation of the knife is the centre of the stock N; but as the
knife extends both sides of the centre the axis of rotation of the knife is in the
plane y y, Fig. 5 and this plane is coincident with the front edge of the step h, as
shown at r. This construction always maintains a portion of the cutting edge of
the knife beyond the vertical inner edge of the guide plate (see Fig. 2) and insures
proper skiving of the material, which does not always occur when one corner of
the knife is in alignment with the guide plate.
In Fig. 6 I have shown a slight modification in the construction of the arm L,
in which the radial slot n, is extended through the material composing the said arm
and is open its entire length. This serves to admit or withdraw the knife through
it, and also permits the use of a wider knife; hence release of the latter is easily
effected by turning the holding screw p, when the knife can readily be taken out.
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 :-
First. In leather (skiving machines, the combination, with the rotary circular

page_text: bed, spring presser-foot, feed rolls and guide-plate, of the cutter or knife disposed
upon a swinging adjustable arm, and capable of adjustment varying its position
vertically as well as angularly with respect to said bed, substantially as stated.
Second. In a leather skiving machine, the combination, with the rotary bed E
and feed roll d, of the presser foot e, arranged as described and provided with the
slot f, and the guide plate g, with its step h, as and for purposes stated.
Third. In a leather skiving machine, an axially adjustable stock, N, and the
skiving knife carried thereby, in combination with a rotary bed, and the swinging
arm L, by means of which vertical adjustment of the knife may be effected and
the cutting edge thereof is maintained in the same vertical plane axially of the
rotary bed E.
Fourth. The combination, with the rotary bed E and its operative parts, of the
swinging arm K, the arm L, with its bore m and radial slot, n, and the knife
stock N, carrying the knife capable of semi-rotation, with its axis of rotation in
alignment with the inner vertical face of the rotary bed E, substantially as
stated.
Fifth. The combination with the standard A, head I, rotary bed E, presser-
foot e, and feed rolls, dd, of the swinging adjustable arm K, carrying the
adjustable knife M, by which the latter can be raised or lowered vertically with
respect to the periphery of said bed E, substantially as set forth.
Sixth. The combination, with a continuous rotary bed E, co-operating with the
feed rolls d d², of the presser-foot e, and the adjustable spring actuated stud S, by
which the tension of the presser-foot is maintained uniform over the entire face of
the rotary bed E, substantially as herein described.
Seventh. A spring actuated presser-foot e, as herein described, and provided
with the slots 1, combined with the feed rolls dd, rctating within slots and
adapted to co-operate with the rotary bed E, to feed the material against an
adjustable knife, substantially as set forth.
Dated this Twenty-third day of February 1897.
EDWIN E. BARTLETT.