Improvements in Sewing Machines.
Year: 1891

page_text: Date of Application, 6th Aug., 1891
Complete Specification Left, 6th May, 1892—Accepted, 11th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in Sewing Machines.
I. FERDINAND SCHMIDT, of 71A Belle-Alliancestrasse Berlin S.W. in the
German Empire, Manufacturer, do hereby declare the nature of this invention to
be as follows:-
My invention relates to certain improvements in sewing-machines, in which a
hook containing the stationary bobbin is made to oscillate; and the object of said
improvements is to facilitate the operation of such machines, and to obviate many
disadvantages attending the use of the same. In carrying my invention into effect,
I arrange the mechanism so that three fourths of a revolution are made by said
hook at each revolution of the main spindle.
An oscillating motion of such an extent has hitherto been unattainable in sewing
machines as ordinarily made and used, and in order that said hook may perform the
required motion, and to improve and facilitate the formation of stitches, a com-
bination of three levers or arms are employed, and the hook is constructed so as
to properly correspond to the movement of the needle.
The mechanism for oscillating the shaft of the hook is as follows:-
Said shaft has at its right hand extremity a crank with a pin, which moves to and
fro within a slot formed in one member of a double lever. The fulcrum of said
lever is upon a short horizontal shaft oscillating between pointed screws, and the
other arm of the lever has a small roller placed at right angles to it, and suspended
by means of a suitable pin or equivalent.
The roller is guided between two parallel cheeks, one above the other, which
are fixed to the extremities of two curved arms, one arm being directed upwards,
the other downwards. The opposite ends of both arms are made in one piece with
a lever or extension of conical shape, the end of said lever or extension opposite
to the curved arms, being fulcrumed to the frame of the machine.
The conical lever with its two curved arms is oscillated by a connecting-rod
moved up and down by the main shaft. The short horizontal shaft on which the
double armed lever with roller and slot is fixed, is embraced by the curved arms of
the conical lever, that is to say, the short horizontal shaft extends through the slot
or space enclosed or formed by said curved arms. The said horizontal shaft afore-
said is stationary and said curved arms oscillate thereon, and around said shaft.
The double lever resting on the aforesaid horizontal shaft is caused to reciprocate
by its roller running between the parallel checks above mentioned, and the slot
within the other arm of said lever actuates by means of the crank-pin aforesaid
the crank of the hook shaft in such a manner that said hook shaft and also the
hook is turned three fourths of a revolution in either direction.
Said hook, thus oscillated at cach turn for three fourths of a revolution has several
distinct parts which are emunerated as follows, that is to say :-
A recess of peculiar shape is provided at the rear of the hook for permitting the
free entrance of the needle; a blank point or projection acting as an auxiliary
holder for the bobbin; also a partition for preventing the thread from slipping off,
a portion of said partition being diminished in height and breadth for preventing
the upper thread from touching said partition at that part.
Said hook is fixed to its shaft in the usual manner, and contains within the cavity
before mentioned the bobbin, which is prevented from falling out of said cavity at
the front by any suitable means for effecting such purpose.
Dated this 2nd dor of August 1891
FREDK. WALKER,
11, Furnival Street, London, E.C., Agent for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Sewing Machines.
1, FERDINAND SCHMIDT of 714, Belle-Alliance Strasse, Berlin, S.W., in the
German Empire, Manufacturer, do hereby declare the nature of my invention and
in what manner the same is to be performed, to be particularly described and ascer
tained in and by the following statement:--
My invention relates to certain improvements in sewing-machines, in which a
hook containing the stationary bobbin is made to oscillate; and the object being
to facilitate the operation of such machines, and to obviate many disadvantages
attending the use of the same. In carrying my invention into effect, I arrange the
mechanism so that three fourths of a revolution are made by said hook at each
revolution of the main spindle.
An oscillating motion of such an extent has hitherto been unattainable in sewing
machines as ordinarily made and used, and in order that said hook may perform
the required motion, and to improve and facilitate the formation of stitches, a
com bination of three levers or arms is employed, and the hook is constructed so as
to properly correspond to the movement of the needle.
In order to make my meaning clear, I will describe the means by which I prefer
to carry out my invention, reference being had to the accompanying drawings, in
which:
.
Fig. 1 is a longitudinal sectional elevation of my improved mechanism, taken on
line yy of Fig. 2.
Fig. 2 is a bottom view of the same partly in section on line a- of Fig. 1.
Fig. 3 is a cross-section, taken on the line a - of Fig. 1.
Fig. 4 is the front-view of the revolving hook.
Fig. 5 is a section through the same, taken on the line -² of Fig. 4.
Fig. 6 is a side-view of the hook.
Fig. 7 is the upper-view of the same.
Fig. 8 is a back-view.
Figs. 9-14 show the manner of forming loops and stitches.
Figs. 15-19 are similar views of the oscillating hook showing also the bobbin
containing the under thread.
Fig. 16 is a sectional elevation taken on line y-y of Fig. 15, and
Fig. 19 a sectional elevation taken on line of Fig. 18.
Figs. 20 & 21 are cross-sectional elevations corresponding to Fig. 3, but showing
other positions of the crank-shaft a and of the parts operated by the same.
Figs. 22 and 23 show the stitches executed by the aid of my improved
mechanism.
Similar letters refer to corresponding parts throughout the several views.
The oscillating shaft to which the hook is secured, is operated by the
following mechanism: The revolving crank-shaft a alternately raises and depresses
the connecting rod b. This rod is linked, by means of a pin b³, to one end of a
hoop e which oscillates between pointed screws d d. This hoop is provided with
two pointed screws e e, placed eccentrically to dd, and constituting the pivots for
the oscillating arm f, which is cast in one piece with a sleeve f' extending at right
anglès thereto, and receiving the sliding rod linked to the connecting rod by
means of a pin 3. The sleeve f¹ is provided with a lateral groove », in which
slides the pin of the crank 3 on the oscillating shaft v. The latter carries, at its
left end, the hook w, fixed to the shaft in the usual manner, and having the following
distinct parts:
A point or catch Figure 4, for seizing the loop formed by the upper thread:
A groove, for the guidance of the upper thread or loop respectively:

page_text: A recess m³, shown in Figure 7, provided at the rear of the hook to allow for the
entrance of the needle;
A dumb projection or heel n', serving as an auxiliary holder for the bobbin ;
A partition p, for preventing the thread from slipping off; said partition being
diminished in height and breadth at p', in order to prevent the upper thread from
touching at that part:
A. recess, to afford free passage to the thread when drawn by the take-up;
A recess s¹, to equalize the weight of the hook.
The operation of the mechanism is as follows: In Fig. 3 the connecting-rod band
hoop c are in their highest position. The pin e¹ in the crank is at the upper end
of the groove ³, and the hook in the position illustrated by Figs. 9, 18 & 19.
Now, as soon as the shaft a and rod begin to move, the hoop e and rod b² are
swung downwards, the latter gliding in the sleeve, and the arm turning on the
pointed screws e e. The pin glides in the groove, and thus the shaft and
hook we begin to rotate. After a quarter of a revolution of the shaft a, the position
shown by Fig. 20 is reached, the crank having accomplished three eighths of a
revolution. The shaft a continues its rotation, and the pin approaches the other
end of the groove, and the crank of said shaft a having reached its lowest point,
as in Fig. 21, the crank has performed three quarters of a revolution.
During the ensuing upward movement of the connecting rod b, the crank ³ and
shaft rotate in the opposite direction for three quarters of a revolution, so
that finally they return to the position shown in Fig. 3. The extent of the oscillating
motion of the shaft » need not be exactly 270°, but may be a little more, and I prefer
to employ a motion of about 280° in order to facilitate the release of the thread
from the catch of the hook.
The bobbin, which is held within the recess of the hook win the ordinary manner,
has been omitted in Figs. 9 to 14 in order to show more distinctly the peculiar
shape and construction of the hook, but may be seen in Fig. 16.
The formation of the stitches is as follows: As soon as the needle has reached
the deepest point, the hook w is in the position shown in Fig. 9. The eye of the
needle is visible above the partition p, and the loop is about to be formed. The
loop is then seized by the catch as scen in Figs. 10 & 18; and the loop is
enlarged, Figs. 11 & 15. The rear part of the loop is drawn behind the bobbin,
and the bobbin finally passes the loop, so as to entangle the upper-thread and under
thread. In Fig. 12 the bobbin is in the middle of the loop; in Fig. 13 the loop is
already thrown off, and the take-up is about to go upwards to form a stitch, Fig. 14,
in which, however, the under thread is not drawn, in consequence of the absence of
the bobbin. The needle moving downwards again, the position in Fig. 17 is
reached.
The stitches produced in this manner are shown in Figs. 22 & 23.
Having now particularly described and ascertained the nature of my said inven-
and in
what
the
to be nerformed I declare that what I

page_text: weight of the hook, and a dumb projection or heel (n¹,) substantially as and for
the purposes herein described.
*Dated this 6th day of Mar 1892
FERDINAND SCHMIDT,
By Fredk. Walker,
11, Furnival Street, Holborn, London, E.C., Agent for the Applicant.