Year: 1889

page_text: 1, FRANZ LEHMANN of Berlin S.O., Naunyn Strasse 39, engineer do hereby
declare the nature of this invention and in what manner the same is to he
performed, to be particularly described and ascertained in and by the following
statement:
My improvements herein after described, consist principally in the use of a
regularly rotating lock stitch hook having a notch in its rim in combination with
an arrangement of the take up, which comes into operation before the rotating
hook enters the last formed loop. In this manner in the rotating hook machine
the one stitch will be begun and perfected before the hook comes to take up the
second stitch.
I am aware that a lock stitch hook with an irregular angular velocity in com-
bination with a take up arrangement has been made previous to my invention;
but a hook which rotates irregularly through the variation in its movements easily
causes tangling during the formation of the stitches and a considerable wear and
tear of the different parts. Further these machines have no notch in the hook
rim and in consequence cannot allow the thread to be taken vertically through the
cloth, which is unquestionably necessary for the formation of tightly drawn, well
finished stitches.
The disadvantages of the horizontally back-and-forward-moving book and rotating
hook machines used up to the present are avoided and the advantages of these two
systems combined in this new rotating hook machine.
Combined with these advantages I have introduced certain improvements in
the manner of transmitting the motion to different parts of the machine herein
after described.
In order to make my invention more clear, I refer to the accompanying
drawings in which similar letters denote similar parts throughout the several
views.
Fig. 1 is a section of my improved machine along line a ẞ of fig. 2, but
showing a view of the hook e, which rotates regularly together with the shatt w
and the take up arrangement ff' ƒ ƒ³ ƒª, which is oscillated by means of the

page_text: grooved disc, so that by each revolution of the shaft w an up-and-down motion
is imparted to the take up lever f.
Fig. 2 is a plan partly in section through the line
8.
Fig. is an end-elevation partly in section along the middle of the needle rod.
Fig. 4 is a section showing the shoes, along the line & of fig. 1.
E
Figs. 5-9 show the different positions of the rotating hook as also the workin
of the take up lever f. p is the spool for the under thread.
g
In the positions shown in figs. 5, 6 & 7 the formation of the loop is shown as
effected by the well known kinds of book machines.
The distinction in the two methods will first be seen in fig. 8.
In this figure
the upper thread loop i is not held on to the hook (by a brush) as has been the
case up to the present but lies free on the hook, whilst that part of the thread
leading up to the cloth, lies vertically in the notch e of the improved revolving
hook. If now the take up leverf which in fig. 8 is in its lowest position, makes the
upward movement shown completed in fig. 1, the loop i will be drawn up from the
regularly revolving or rotating hook and the stitch will be correctly formed by
the vertical leading up thread it, before the point el of the hook can pass behind the
thread which is lying close on the needle, or rather before the point of the hook can
pass through between the needle and thread. The protecting sector serves to protect
the loop, hindering a tangling of the same.
Fig. 10 shows a top view of the notch e in the rim of the improved rotating book,
so that a projection is formed. This projection serves to catch up the thread. The
characteristic features of the formation of the lock stitch having now been set forth, I
proceed to the description of the mechanism of the same.
The over thread coming from the spool, passes through the guiding eye o; it then
passes through the eye of the take up lever and from there through the eye of the
needle. The take up lever ff has the pivot d. The link catches on to ¹, the
other end of which (*) is fastened to the double armed lever ff; f is the pivot of
this lever.
On the arm a roller g is fixed, which runs in the eccentric or winding groove on
the disc n.
The tightening of the stitch can be regulated by setting the arm f¹ of the
angle lever ff. The disc n is coupled by means of the screw to the eccentric m
which is keyed on to the shaft w. The shaft w receives its motion by moans of the
sheave pulley m².
The needle receives its motion from the shaft wo by means of the eccentric m which
works the eccentric rod e. This rod e is connected by means of the connecting
piece to the double armed lever ee, which works the needle rod up and down.
Besides this peculiar driving mechanism just described for the needle rod and take
up lever, the motion of the feeder is not the same as in the machine used up to the
présent.
The motion of the feeder is the following:
The feeder is carried by the piece
The piece is guided by the pin
is therefore able to swing on this axle
forward movement on the same.
which moves in the guides h (fig. 4).
whereon it hangs. The pieces
as well as having a backward and
is further supported by the eccentric which is
fixed on to the main shaft w and serves to lift the feeder. The spring e serves to
draw the shoe back in its guides, in the direction of the arrow in fig. 4) and its
forward motion and that of the feeder-is caused by the working of lever o² o³, the
pivot of which is at o*.
The arm o has a vertical pin oº moving in a slit in the arm o, which arm is held
continually against the sloping side of the uneven disc by the working of the
spring e.
The uneven disc is fastened to the main shaft w.
The slotted arm o is adjustable in a vertical direction by means of the angle
lever K K and the position is always shown by the pointer arm
K' of the lever K¹K
on the outside.
By means of the vertical adjustment of the arm o³ the motion imparted to this arm

page_text: by the uneven disc may be regulated, and in consequence the motion of the feeder
also.
The advantages of the different modes of communicating the motions are principally,
the convenient transmission of the power and the easy adjustment of the different
parts.
Another important part of this rotating hook machine is an arrangement, by which
it is possible to make a simple chain stitch seam with this machine.
For this purpose the hook e e¹ is removable from its place.
To remove the same it
is necessary to press the button K' (Fig. 2) which moves a feathering lever K³ having
its pivot in the shaft w, its one end acted on by a spring lying in the shaft, by pressing
which the pin K' on-the other end will be drawn out of the spindle of the hook-which
can then be drawn out of the main shaft and the looper G for making simple chain
stitches shown in figs. 11-12-can then be substituted.
By removing the screw the eccentric working the take up will be set out of gear
and the machine can be used as a simple chain stitch machine.
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 in sewing machines:
1.) A regularly rotating hook having a notch and a projection in its rim, for the
purpose as described.
2.) The combination of a regularly rotating hook with an adjustable take up lever,
for the purpose as described.
8.) The combination of a rogularly rotating hook having a notch and a projection
in its rim, with an adjustable take up lever, for the purposo as described.
4.) The combination of a regularly rotating hook having a notch and a projection in
its rim, with a disc having a winding groove communicating motion to a double lever
arm, the same working the adjustable take up lever by means of a second arm, having
an adjustment on its end, for the purpose as described.
5.) The combination of a feeder consisting of a shoe guided by a rod and having
in addition a swinging motion with an eccentric giving it an up and down motion,
with a regularly rotating hook and adjustable take ap lever, for the purpose as
described.
6.) The combination of an arm vertically adjustable and working in conjunction
with an uneven disc, and an angle lever for adjusting the feeder, and having a
pointer showing its exact position of adjustment on the outside of the machine,
with a regularly rotating hook and with an adjustable take up lever, for the
purpose as described.
7.) The combination of an arrangement for removing the hook, consisting of a
lever having its pivot in the main driving shaft of the machine and being worked
by a button from the outside with an end coupling mechanism for the adjustable
take up lever, for the purpose as described.
8.) The combination of a disc having a winding groove with an eccentric con-
veying the motion to the needle and with a screw by means of which the same
may be placed out of gear with a regularly rotating hook, for the purpose as
described.
Dated Berlin, this 4th day of April 1009.
FRANZ LEHMANN.
By A. Kuhnt & R. Deissler,
38, Alexander Strasse, Berlin C., Germany,
Agents for Applicant.