Improved Method of Driving the Feed Motion of Sewing Machines for Knitted Fabrics.
Year: 1889

page_text: Date of Application, 4th Mar., 1889
Specification Accepted, 6th Apr., 1889
Improved Method of Driving the Feed Motion of Sewing Machines
for Knitted Fabrics.
I JULIUS KÖHLER of Limbach, Saxony, Manufacturer of Sewing Machines do
hereby declare the nature of my invention for "IMPROVED METHOD OF DRIVING THE
FEED MOTION OF SEWING MACHINES FOR KNITTED FABRICS," and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement and accompanying drawings,:=
My said invention relates to machines for sewing knitted fabrics and has for its
object an improved arrangement of mechanism for feeding the materials to be sewn
past the needle of such machines.
In order that my invention may be more fully understood I will proceed at once to
describe the same with reference to the accompanying drawing. In the said drawing
the same letters refer to the same parts in the different figures. In the said drawing
Fig. 6 is an elevation, and Fig. 7 a plan partly in section showing so much of the
general arrangement of a hosiery sewing machine as is necessary to show how my
invention is applied. One of the feed discs, viz: bis mounted on a vertical shaft to
which intermittent rotary motion is imparted by the driving disc A to be hereinafter
referred to. Fig. 3 is a plan on a larger scale showing the details of my said
invention and Figures 2 and 4 are sectional olevations through I-II and III-IV
respectively of the said plan. Fig. 5 illustrates an alternative mode of applying a
brake or check to one part of my said invention and Fig. 1 illustrates the method of
actuating the driving discs for rotating the feed rolls which has heretofore been usually
employed.
.
In the class of sewing machines to which my said invention is applicable the edges
of the fabrics which are to be sewn together are fed between the feed discs a and b
Fig. 6 which feed the materials past a horizontally moving needle. As in hand
sewing it is desirable that the length of stitch shall correspond to the length of mesh
in order that the needle may pass through each mesh, but inasmuch as the length of
mesh is variable on account of the varying degrees of fineness of knitted fabrics it is
requisite in order to obtain such a result that the intermittent forward motion of the

page_text: material shall be capable of being regulated at will to suit the gauge or size of mesh
of the material to be sewn. This consideration renders the use of a ratchet wheel as
a method of rotating the feed discs inapplicable and the arrangement shewn in plan
Fig. 1 is usually employed for obtaining the desired variable feed. In this figure
represents a driving disc which is mounted on the same shaft as one of the feed
rols for the purpose of imparting rotary motion thereto and having a raised rim has
shown in section at the left side of the figure A lever e lies on the top of this
driving disc and has two lugs or projections c d between which the rim of the
driving disc passes. If the other end of the levere is moved in the direction of the
arrow the lugs c and d grip the edge of the driving disc and take it with them a
distance depending on the extent of the lateral movement of the lever e. On the
levere moving backwards in the direction of the arrow g the lugs c and d release the
rin and a spring e' draws back the lever until the lugs again come into contact with
the rim.
By varying the range of movement of the lever e the desired amount of feed or
length of stitch to suit the mesh is obtainable but this device is subject to the dis-
advantage that at times the lugs fail to grip the rim instantaneously and in this case
either the stitches become irregular or the feeding forward of the work ceases.
In order to overcome this defect I according to my said invention apply to the
driving disc the following device. The disc A, Figs. 2 and 3, is provided as usual
with a rim or flange on both sides, indicated by the letters A1 and A2 and has in
addition a boss A³ which may conveniently be made in a single piece with the disc A
as shown in the drawing. In the depression in the upper side of the driving disc I
place a catch B which serves to rotate the driving disc. In the corresponding
depression in the under side of the driving disc I place a counter catch of a similar
form to the upper one (as shown in dotted lines in Fig. 3) but opposed thereto.
The catches B and C are pivoted respectively on the screws and attached to the
freely moving discs D) and E. A spring Fig. 3 continually tends to keep the
edge B1 of the catch in contact with the rim of the feed disc.
P
On the lateral surfaces of the feed disc are placed cover plates F and G, Fig. 2
which can rotate about the boss of the driving disc A. Adjustable collars and
provided with set screws serve to hold the covers in position. I provide the covers F
and G with projections and m preferably screws as shown in the drawing which
enter into slots in the ends of the catches B and C.
'
If the catch B Fig. 3 is caused to turn about its pivot in the direction by the
rotation of the top cover plate F the corner B₁ will be removed from contact with the
rim A of the driving disc A and the catch B with its thin disc D will rotate about
the axis of the driving disc A. The counter catch C will meanwhile prevent the
rotation of the driving disc itself.
If on the other hand the cover F is rotated in the direction of the arrow y the
corner B of the catch B will come into contact with the rim A' and take the driving
disc along with it in such a manner as to cause it to rotate about its axis in the
direction of the arrow y.
The perfect action or grip of the upper catch B by means of which the driving disc
is rotated can only take place if the thin disc D carrying the pivot i of the catch B
becomes immovable directly the catch is moved in the direction of the arrow y. To
effect this a brake or check is applied to the disc D before the catch B comes into
action.
Various modes of applying a brake to the disc may be used and two such methods
are illustrated in Figures 4 and 5.
A bolt H Fig. 4 arranged so as to slide vertically in the coverplate F is pressed at
the proper time by a spring at the end of a bent lever K Figures 6 and 7. This
lever K is provided with a roll bearing against the excentric boss of the cam L which
atuates the feed catch B of Fig. 3. For the latter purpose a lever M provided with
a roll which bears against the suitably shaped surface of the cam L is connected to a
forked projection of the coverplate and causes the latter to rotate so as to move the
catch B about its pivot in the manner herein before described.

page_text: For the counter catch (on the underside of the driving disc such a brake or
check is not necessary and the coverplate is simply connected to a fixed arm G¹
Fig. 6.
Another method of applying a brake or check to the disc D is shown in Fig. 5. To
the disc Da movable arm N is attached having two lugs which continually tend to
grip the rim A' of the driving disc owing to the pressure of the spring N¹. By this
means it is only possible for the disc D to move in the direction indicated by the
arrow Z; on an effort being made to move it in the reverse direction it is held fast
and the catch B must take the rim A' with it.
The length of the stitch will depend on the distance the driving disc A is caused to
rotate and this can be readily regulated to suit the length of mesh in various ways as
is well known.
Having now particularly described and ascertained the nature of ny said
invention and in what manner the same is to be perforined 1 declare that what
I claim is
1. In machines for sewing knitted fabrics the combination of parts constituting an
intermittent feed motion substantially as herein before described and shown.
2. The driving disc A actuated by the catch B pivoted at i in a freely revolving
disc D provided with a brake or check the whole acting substantially as herein before
described for the purpose of imparting an intermittent rotary motion to the feed disc
of a sewing machine for knitted fabrics.
JULIUS ALLMANN & Co.,
70, Deansgate, Manchester,
Agents for Applicant.