Improvements in and relating to Tension Devices for Threads in Welt Stitching Machines.
Year: 1899

page_text: Date of Application, 7th Oct., 1899-Accepted, 11th Nov., 1899
COMPLETE SPECIFICATION.
Improvements in and relating to Tension Devices for Threads in Welt
Stitching Machines.
I, HEINRICH WALTHER, of Frankfurterstrasse, Offenbach-on-the-Main, in the
Empire of Germany, Mechanician, 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:—
My invention relates to tension devices for threads in welt stitching machines.
In welt stitching machines the use of a tension device constructed according
to my said invention enables the tightening and braking of the thread to be
effected with certainty so that the needle will always have to draw such thread
when under tension, which is of great importance for good and accurate
stitching.
In the accompanying drawing:
Figure 1 represents my improved tension device applied to a welt stitching
machine, the front column being supposed to have been removed as also other
unimportant parts of the machine.
Figure 2 shows the tension device by itself, with its parts in the position which
they occupy at the moment of drawing the thread.
Figure 3 is a side elevation of part of the machine with the device.
This tension device comprises a rod c which is arranged to move to and fro
in guides c on the frame a. The rod c has teeth at its front end to form a
rack, behind which it is recessed so that a toothed pinion adapted to revolve
upon a pin or journal f¹ can move freely over the recessed portion of the rod c,
but in the return movement of this rod engages with the teeth of the rack and
is turned.
As the thread m comes from the pitching vessel it is wound several times round
the roller b which is pressed against the toothed pinion by a spring g through
the medium of the nut f at the end of the screw-threaded pin or journal f¹.
From this roller & the thread m passes over the roller of the looper r, and
thence through the eye m¹ to the lower part of the looper.
As soon as the needle, actuated by the lever p¹, has pierced the welt, the
tension device commences to operate.
.
Upon the cam disc is provided a projection which at the proper moment
travels over the roller d¹ of the lever d, forcing it down and turning the lever
pivoted at q.
By this movement the lever d through the intervention of the arm g¹ con-
nected with the rod c, causes this rod to slide backwards, and the roll b to turn,
thus putting the thread under tension.
As the device is set in operation the brake is applied to the thread, thereby
increasing the tension.
Now the needle draws the thread while under tension; during this time the
projection n on the cam disc has however passed the lever, the roller d'
travels again upon the periphery of the disc k, and the lever is caused to return
to its original position by the spring e.

page_text: In consequence of this movement the rack must of course be forced forward
again, for enabling the roller band with it the pinion h to move freely again.
By means of a spring e¹ the rod c is forced upwards against the pinion h so
that the rod will not be liable to jam.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
First. A tension device for threads in welt stitching machines, wherein the
thread m guided over the roller b will, after the needle has pierced the welt,
be put under tension and have the brake applied during the rotation of the
cam disc by means of a lever d, rack c and pinion so that the needle has
always to draw the thread while under tension, substantially as set forth.
Second. In tension devices for welt stitching machines the lever d jointed
to the arm g of the rod c and provided with the roller d', which lever in the
rotation of the cam disc is moved by means of the projection, in order to
shift the rod c forming at its front extremity a rack, thereby turning a pinion /
engaging with this rack, and rotating the roller 6 upon which the thread is wound,
the lever after the projection has been passed being caused to return to its
original position by a spring e so that the rack will be liberated from the pinion,
substantially as set forth.
Third. A tension device for welt stitching machines constructed and operat-
ing substantially as and for the purposes herein set forth with reference to
the accompanying drawing.
Dated this 7th doses of Dotobor 1800
J. LINCOLN & Co.,
75, Chancery Lane, London, W.C., Agents for the Applicant.