IMPROVEMENTS IN SEWING MACHINES, AND IN APPARATUS CONNECTED THEREWITH
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Lorentz Albert Groth at the Office
of the Commissioners of Patents on the 9th October 1883. Communicated
to him from abroad, by Gustav Fraenkel, of the firm of Rosenberg & Fraenkel,
of Berlin in the German Empire.
LORENTZ ALBERT GROTH, K,G,V, Civil Engineer and Managing Director, of The
Universal Inventors and Patentees Financial Company Limited, 30 Finsbury
Pavement London E.C. "IMPROVEMENTS IN SEWING MACHINES, AND IN
APPARATUS CONNECTED THEREWITH A communication to me from abroad by
Gustav Fraenkel, Proprietor of the firm of Rosenberg and Fraenkel of Berlin in
the German Empire
»
As is well known a covered seam is obtained in leather by making an oblique
incision in the surface thereof, in the direction of the seam, this incision is called
the channel and in it lays the seam of stitches which is then pressed down and
covered over by the edge of the channel.
Heretofore the production of a seam in this manner, which has only been possible
by hand, has required that the closing of the channel should be effected by a
separate operation after the completion of the sewing. By one part of the
improvements forming the subject of the present invention, the sewing in the
channel and the closing up of the latter is effected at one operation.
The arrangements for producing sewn boot or shoe soles, is of the following
character the presser foot is bent inwards, so that the work can be guided freely
round the front, and both sides of the needle.
The foot of the presser is so shaped that the two side edges towards the needle
hole, run to a point, and round the needle hole, leave standing only a narrow iron
stem.
This pointed form is necessary to enable the concave edges of the soles to be
guided close round the needle hole, without coming in contact with the corners of
the presser foot. An upwardly & outwardly increasing needle sheath forms an
important part of the presser foot.
This needle sheath serves on the one hand as a guide and protection for the
upper leather of the boot or shoe from the needle and on the other hand as a
protection for the needle in sewing upon iron objects such as splash boards of

page_text: carriages, buckles and so forth, as to which mention will be made hereinafter. In
order to hold the upper leather quito clear of the edge of the boot, so as to
prevent the hiding from view of the seam, in course of formation, a protecting
plate is arranged which holds the upper leather down.
The guide for the sole of the boot or shoe is adapted to the presser foot and to
the needle plate.
Both parts are adjustable according to the width of the edge of leather which
projects beyond the seam. The guide of the presser foot is formed by a cramp and
that on the needle plate is formed by a plate. According to one modification of
the presser foot, the surface of the foot of the presser is broadened by a moveable
piece in order to extend the pressure to a greater length of seam. For this purpose
there is placed under the foot, a lever like piece, which is pressed forward by a
blade spring, fixed to the presser foot in straight seams, but in inside concave
seams is pushed back by the boot or shoe.
According to another modification of the presser, the foot thereof is kept very
narrow, and at its two sides are placed two side feet which are carried by special
stems, which lay close to the stem of the main presser foot, and are held down by
special springs, whilst they can each be raised if required by means of separate
levers.
Another part of the invention relates to the needle plate; this is raised in the
form of an anvil, so that room is obtained for bringing the curved sole of the boot
or shoe, into every position in relation to the needle.
Close beside the needle hole is placed on one side a small spike, which holds the
channel open; behind the needle hole is placed a wedge shaped piece which presses
the edge of the channel upwards and closes the channel, while the pressure of the
presser foot acts at the same time from above.
In order to secure sufficient play for the free edges of the sole on its way over
the needle plate, there is a channel on the said needle plate, and in the periphery
of the needle hole.
The feeder lays hold of the leather by means of two or more teeth, always in the
open channel, and pushes it forward so that the traces of the feed bar do not
remain visible on the work, but are covered by the seam.
This apparatus is also applicable to the sewing up of splash boards.
In this case likewise the anvil like needle plate is employed, the surface of which
is however quite smooth and of very small circumference, so that the sewing can
be carried correctly into the sharp corners of the splash board. The presser foot is
likewise quite smooth and carries a sheath for protecting the needle from the iron
frame of the splash board which has to go close to the needle hole.
The same arrangement serves also for sewing up buckles and other similar
objects. For producing driving bands and such like articles with covered seams
on one or both sides, a spike is connected with the presser foot similar to that on
the needle plate, and the pressing back of the seam is effected, as before described,
by a wedge shaped projection on the presser foot similar to that on the needle
plate.
In the production of driving straps which consist of several layers of thick
leather, as also in the sewing up of varnished leather, in splash boards, for example,
it has been found necessary to reduce the resistance of the needle arising from the
friction of piercing the leather.
This can only be accomplished by lubricating with oil, or better still with tallow.
For this purpose it is necessary to apply the lubricating material to the point of
the needle, shortly before it is pressed into the leather, and in order to effect
this automatically by the sewing machine, the following apparatus is fitted
thereto
At the height of the point of the needle, when in its highest position, is placed a
horizontal cylindrical tallow box, directed towards the needle. This tallow box is
somewhat like a syringe, and is fixed in a guide socket, carried by an arm placed

page_text: at the head of the machine, the tallow box is however adjustable in the direction
of its axis towards the needle, so that the mouth of the box and the stump of
tallow issuing from it, touch the said needle.
A spiral spring presses the tallow box back again each time.
The application of the lubricant is effected by the working of the machine in the
following way.
On the circumference of the crank plate is a cam which moves a double armed
lever. The lower end of this lever carries a small hammer, which strikes against
the end of the tallow box each time the cam forces away the end of the lever, and
this causes the lubrication of the needle when in its highest position as above
described.
The lever is always drawn towards the circumference of the crank plate by
means of a spiral spring, but without directly touching it, so that the hammer
remains at a distance from the tallow box, and the latter is held away from the
needle by a spiral spring.
If it is required to put the lubricating apparatus out of action, a screw is
loosened, whereby the upper end of the divided, but hinge jointed lever arm, can
be removed so far from the crank plate, that contact with the cam is prevented.
The tallow box is so placed that it goes past the presser foot whereby it takes a
direction oblique to the needle.-The tallow box is fitted with a special internal
apparatus for effecting the delivery of tallow by the strokes of the hammer, which
have always the same amount of movement.
In the tallow box is a suitable piston, which has a hole through its centre,
furnished with a screw thread. Through the piston passes a small screwed spindle
with a quick thread, which spindle rests against the cover of the box by means of
a shoulder and carries a button outside the cover.
Between the cover and the button is a spiral spring which does not however
bear against the cover, but against a small special disc, or washer which only
touches the cover on a small ring shaped surface, in order to reduce the friction on
the cover to a minimum. The tallow box itself is drawn out of the guide by a
spiral spring, until a shoulder on the box comes in contact with the guide. This
spring must be somewhat stronger than the spring, between the cover and the
button.
When the hammer which is covered with cloth, strikes the button, the piston
suffers a slight displacement, at the first instant of the stroke, by the sudden blow,
because the button by reason of the friction of its great bearing surface, is
prevented from turning so much as to screw into the piston instead of the piston
being moved. The hammer has not yet however made its whole stroke, but the
cylindrical part close behind the button, bears upon the box cover, & the rest of
the stroke of the hammer, occasious a movement of the whole tallow box, the
mouth of which touches the needle
As soon as the hammer returns into its position of rest, the stronger spiral
spring forces back the tallow box likewise, and when the latter reaches its stop, the
spring between the button and the cover of the box, presses back the loose spindle
a short distance, and the piston follows the spindle, because both are connected
together by screw threads. If however the strength of the spiral spring is not
sufficient to overcome the friction of the circumference of the piston, and the
adhesion of the tallow; the spindle is allowed to turn back automatically, by the
quick pitch screw. The small diameter of the spindle, and the avoidance of friction
between the spiral spring and the box cover, by the introduction of the disc or
washer, produces so little resistance that the turning back of the spindle is easier
than the drawing back of the piston
This turning back of the spindle and the next forward movement at the next
stroke of the hammer is synonymous with a continuous slow turning of the spindle
which would equally well displace the piston and press out the tallow little by
little,

page_text: A further important device for leather sewing machines for the production of
covered seams, is the apparatus for conducting fluid adhesive material, into the
channel of the seam, close behind each new stitch, before the seam is covered by
the pressing down of the edge of the channel. This device consists of a holder
containing the adhesive material, placed at the upper back part of the machine, and
the channel guides in the leather are fed with adhesive material from the holder
through small pipes.
The adhesive material for the under channel is conveyed through one of these
pipes, which passes for example, below the base plate to the outlet opening by the
Bide of the needle hole. The other pipe which feeds the upper channel, opens first
into an upright pipe fixed in the presser foot by the side of the needle hole.
In order that the outflow of the adhesive material should only take place while
the machine is at work the outflow, is made dependant upon the working of the
machine.
For this purpose there is connected with the holder of adhesive material a lever
which carries a rod, the lower end of which shuts off the tubular outlet from the
bottom of the holder.
The other end of the lever is acted on by a cam connected with the driving
gear of the machine thereby occasioning a rise of the said rod.
This rod is flattened at its lower end, to such an extent that when in its highest
position, a flow of the adhesive material takes place through the space left thereby.
If the material should be unable to flow of itself by reason of insufficient
pressure, this can be increased by a floating piston in the holder.
For sewing larger and heavier pieces, a crane is employed for effecting the to
and from movement of the work, during the sewing, in the machine, whereby the
operation is so far lightened and accelerated that the guidance of the work is not
dependant upon the cooperation of several people as heretofore.
By the help of this crane one workman alone can attend to the sewing of a piece
of work, because he has only to attend to the guidance of the work.
The crane apparatus consists of a frame which can be turned round its point of
suspension fixed to the ceiling.
This frame carries a pair of traversing rails, on which rolls a carriage, which
carries on both sides chain rollers, keyed on a common axis. Over the rollers pass
chains, which on the one side carry a pair of tongs, and on the other counter-
weights. The latter can be increased by adding disc weights as may be required.
By this means when the crane is not employed the weight does not draw the
chains over the rollers, and the said chains cannot fall from the rollers, as chain
guides are arranged, against which the tongs come and prevent a further fall. Or
the tongs can be hooked over the other end of the chain.
The carriage itself consists of a double pair of rollers whereby the ends of the
chains are always guided parallel.
+
The tongs by which the chain seizes the work, take the place of the temporary
fixing of the varnished leather, over the iron frames, which has been necessary
heretofore
.
The clamping by which a contact of the leather is effected, occurs in this case
exactly in the path of the seam to be formed. The legs of the tongs are for this
purpose furnished at the ends with smooth rounded cheeks, which set without
damage, on the back leather, and behind them are the tong cheeks, which are
toothed and of cutter form. A pin placed in the lower leg serves as a fulcrum and
at the same time a point of suspension, whilst a powerful spring holds the two
cheeks together.