Improvements in Sewing Machines.
Year: 1891

page_text: Date of Application, 8th Sept., 1891-Accepted, 6th Aug., 1882
COMPLETE SPECIFICATION.
Improvements in Sewing Machines.
We, MAX HARFF, Manufacturer, of 78, Schildergasse Cologne, and EWALD
BRUNCKER, Manufacturer, of 181, Dürenerstrasse Cologne-Lindenthal, both in
the German Empire, 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 means or mechanism for producing the motions
which are necessary in double lock-stitch sewing machines, and has for its object
to combine simplicity of construction with perfect operation.
All motions, except that of the cloth guide or the feed motion take place in one
plane.
In the further description, reference will be made to the accompanying drawings,
of which;
Fig. 1 is a side elevation of a machine embodying our invention.
Fig. 2 is a front elevation.
Fig. 3 a side elevation showing the side opposite to that shown in Fig. 1.
Fig. 4 is a detached view of the crank which forms part of the new mechanism.
Figs. 5, 6, 7 and 8 show the four principal positions of the crank and of the
slotted levers operated by the same.
Fig. 9 represents the shuttle in the position, which it occupies, when it has moved
beyond its guide or shuttle race for renewal.
Fig. 10 shows the cloth guide or feeder.
The crank a which imparts motion to the whole mechanism, acts directly upon a
pair of slotted levers c and e. The slots of the said levers are shaped in a special
manner. One of the slots 6 is formed in the needle-operating lever c, and the other
slot d is formed in the lever e, which sets in motion the shuttle arm f, as well as the
cloth feeder h, and which turns on a fulcrum pin fixed to the machine frame.
The cloth feeder h is suspended in the recesses k and I of the arm e, which are
curved concentrically, and so that each of them forms a broken line. The recess ↳
in conjunction with the wedge shaped tooth m (Fig. 10), serves to lift the cloth
feeder, and to push it forward, while the down motion and the withdrawal of the
feeder is effected by the spring n. The different parts are arranged in such a
manner, that the turning or shifting of the cloth feeder takes place as if it were
pivoted at h¹. Fig. 10 shows its highest position, when it has been drawn to the
extreme left by the wedge shaped tooth m. When the tooth m recedes and thereby
the cloth feeder becomes free, the spring n, one of its ends being situated in an
aperture of the feeder h, draws the latter to the right, and thereby causes the feeder
also to descend.
The length of travel of h towards the right may be determined or regulated by
adjusting the arm n².
The arm f carrying the shuttle is pivoted to the pin and receives its oscillating
motion from a pin e' fixed on the arm e. The said pin or stud el rests against a
tooth or projection f' of the shuttle-carrier f, and also against a tooth of of the
pawl o fixed on the shuttle carrier f, whereby the pin e', when the pawl o occupies
the position represented by Fig. 3, is connected with the shuttle-carrier, and causes
the latter, together with its shuttle, to take part in the motions of the pin e' mounted
A spring f³ serves to keep the pawl o in contact with the pin e. When the
pawl o is released, the pin e' becomes free, in consequence of which the shuttle armƒ
may be turned beyond its guide or race, so as to allow the shuttle to be exchanged.
This position is represented by Fig. 9.
on e.
The curved or angular slot d formed in the levere has such a shape and position,

page_text: that besides producing the motion gf-the-cloth feeder h by means of recess 1 and
tooth m, it also imparts to the shuttle its to-and-fro motion by means of the arm f,
which motion is interrupted by a short period of rest,
This period of rest, (produced by the shape of the slot) occurs before tightening
or drawing in the lower or shuttle thread, which is still loose, and after the said
thread has passed through the loop, so that the upper thread may slide freely at
the back of the same.
•
The slot in the needle operating lever c lowers the needle bar, together-with
the needle, subsequently lifts the same to form the thread into a loop; it allows
the needle to rest until the shuttle has passed through-and-guides the needle upward.
All these motions have their origin in the slots 6 and d formed in the levers cand
and the latter are set in motion directly by a crank a shown in Fig. 4 passing
through the said slots. The lever p is a simple thread guide actuated by a spring
and moveable between two stop pins s, s¹, fixed to the needle bar Fig. 1.
In order to establish exact agreement between the motion of the thread guide (or
the tightening of the upper thread) and the motion of the shuttle (or the tightening
of the lower thread), as required by the sewing process, the lower edge of the thread
guide p has an angular shoulder p², in consequence of which the said thread guide
completes its outward stroke sooner than the needle bar which sets it in motion, and
this in accordance with the motion of the shuttle. Owing to this arrangement, the
thread guide is at rest, while the needle bar completes its upward motion. The
slots in the levers cand e thus serve to produce all the various motions which
operate together for the sewing process, by the aid of recess I, tooth m, and thread
guide p.
The screw spindle r, Fig. 3, serves to fix the machine on a table, after it has
been detached from its stand.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare, that what we
claim is:
-
A double lock-stitch sewing machine, provided with a driving axle a which works
simultaneously in two curved slots, one of the said slots being formed in the needle
operating lever c and serving to produce the motion of the needle, while the other
slot is formed in an arm e and serves to produce the motion of the shuttle and of
the cloth feeder, substantially as described.
1
Baicu OLIS FOR day of September 1901.
MAX HARFF,
EWALD BRUNCKER,
By Fairfax & Wetter,
433, Strand, London, Patent Agents.