Improvements in Chain-stitch Sewing Machines for Producing Ornamental Stitching.
Year: 1899

page_text: Date of Application, 7th Mar., 1899-Accepted, 7th Mar., 1900
Improvements in Chain-stitch Sewing Machines for Producing
Ornamental Stitching.
I, BERNHARD KOEHLER, of No. 41/43 Zwickauer Strasse, Chemnitz in Saxony,
in the Empire of Germany, Manufacturer, 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 has for its object to produce in the chain-stitch sewing machine
strongly raised ornamental stitching, the pattern of which may be varied through
the interchange of shaped cams mounted on certain parts of the machine.
Referring to the drawings which form part of this specification.
Fig. 1 shows, seen from below, the lower portion of the mechanism of the sewing
machine provided with my improvements;
Fig. 2 is a front elevation of the complete machine;
Figs. 3, 4, and 5 illustrate in side view and in three different positions, the
working mechanism of the looper or loop catcher;
Figs. 6, 7, and 8 are respectively a sectional, a plan, and a front view of the
latter;
Figs. 9 and 10 illustrate the working of the looper, and
Figs. 11, 12, 13, and 14 illustrate the formation of the stitch in its various
stages.
As shown in Figs. 9-14, the looper or loop catcher f is so contrived as to
seize the thread loops of the needles n¹ and n², and to hold them open in such a
manner as to ensure the passage of needle n¹ through both loops at the next
succeeding down stroke of the needle bar, Figs. 10--12.
In order to attain this end the following problems had to be solved:-
1) That the needle n' should be made to pass with certainty and without fail
through the bights of both loops held by the looper f, even if the plane formed
by the needles is placed in an oblique or diagonal direction or position to the direc-
tion of the feeding action of the machine. This object is attained by providing a
longitudinal groove or channel in the looper shank, which shank keeps the loops
distended, and into which groove or channel the needle n¹ enters upon the down
stroke of the needle-bar, as indicated in Fig. 12.
2) That the direction of the stroke of the looper point relative to the needle
plane should be maintained, that is, that the looper and needle-bar should turn
simultaneously upon an identical vertical axis, Fig. 11 and 14.
3) That the looper should without fail or deviation perform the same forward
and backward movement or stroke and receive the same axial displacement,
irrespective of the actual position its shaft may occupy at the moment the stroke
is made, Figs. 11 and 14.
For the purpose of solving the second problem, the following arrangement,
illustrated in Figs. 1 and 2, has been contrived: The needle bar N is made
turnable in bearings 1 and 2 and in ring 7, the latter being connected with the
lever arm by link g. The clamping rings 2 and 3, rigidly secured to the
needle-bar N, compel the latter to participate in the upward and downward

page_text: movement of ring 1, and the upper square end of the said needle-bar carries a
crank, which is connected by rod with crank mounted upon the upper
end of the vertical shaft w; to the lower extremity of the vertical shaft wa lever
h2 is rigidly fixed, and is connected by rod with crank mounted upon the
looper shaft w³.
The turning of the vertical shaft w, together with needle-bar N and looper
shaft, both connected with shaft was herein before described, is effected in the
following manner :-
A worms secured to the driving shaft W, is made to engage with toothed
wheel R mounted upon a sleeve H, whereby the latter and the peripherally
channelled or fluted disc e rigidly connected therewith, are turned for a certain
number of degrees at a time. (30 degrees in the device as illustrated).
A roller mounted on lever or crank, the latter being clamped to vertical
shaft W, and influenced as indicated in Fig. 1 by spring f2, is made to follow the
peripheral curves of disc e. Owing to the conformation of the thread of the
worms (Fig. 1). the turning of the disc e is effected at the moment when the
needles are out of the material, so that the plane of the needles and the plane of
the stroke of the looper f are held stationary during the formation of the stitch.
In order to meet the requirements mentioned under (3), the contrivances
illustrated in Figs. 6, 7, and 8, and hereinafter described have been provided:-
Upon the head of the vertical shaft is mounted a suitably shaped frame m
provided with bearings for the spindle f¹ of the looper, the said shaft also
carrying the sleeve m which is made vertically displaceable but not turnable,
upon the shaft. An angle piece is screwed to the sleeve m² and holds a guide
block or roller which is inserted into a slide slot f provided in an angle arm
of the looper shank holder, causing the said looper f to oscillate upon its spindle
in a forward or backward direction at each up and down stroke of the sleeve m².
A second sleeve m³ (Figs. 6, 7 and 8) is pushed over sleeve m² and is made
vertically displaceable but not turnable upon the latter; steel guide blocks o¹
and o² are secured by means of screws or in other manner to the sides of sleeve m³
and their inner surfaces are provided with suitably contrived oblique guide
grooves in which engage the ends of looper spindle f¹, projecting from its
bearings on head m', in order to effect the lateral displacement of looper f and
the direction of its stroke in accordance with the up and down movement of
sleeve m³.
The levers q and q which are operated by means of rollers s' and s² engaging
with the rim of cam n the latter being mounted upon and receiving its rotary
motion from horizontal shaft wel, effect the vertical displacement of aforesaid
sleeves m² and m³ by the pressure of rollers or studs p¹ and attached to afore-
said levers which engage in corresponding annular grooves cut out in the lower
parts of sleeves m² and m³.
The shaft receives its motion from the driving shaft W though eccentric &¹
rud and crank 13.
Figs. 11, 12, 13 and 14 serve to illustrate cooperation of looper f and needles n¹
and n² in forming and producing the ornamental stitch.
Fig. 11 shows the relative positions of looper f and needles n¹ and n² corre-
sponding to the position illustrated in front view in Fig. 2. The needles
and
3 are in their lowest position, and the looper f is in the act of seizing the threads
of needles n¹ and n² (Figs. 4, 11, & 12.) Upon the needles being withdrawn from
the material and the latter being pushed forward by the feeder to the extent of
the length of the stitch, (Fig. 13) the needles and the looper assume the position
shown in Fig. 13.
The thread loops taken from the needles when the latter were in their lowest
position, are still held by the looper when the downward movement of the needles
is repeated, and the needle n¹ enters the longitudinal groove in the shaft or shank
of the looper f, and therefore with absolute certainty, also passes through the
bights of the loops held distended by the loop shank. The looper f thereupon

page_text: moves into the position shown in Fig. 14, whereupon the same operation is re-
peated from the opposite side of the central line of the stitching.
By providing and mounting other discs e, differing as to their peripheral
channellings or flutings from that illustrated in the drawings, the operation of
the machine can be altered within certain limits and different styles of orna-
mental stitching can be produced.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is:-
:-
1) In chain-stitch sewing machines having two or more needles for producing
ornamental stitching, the application of improved mechanism for axially dis-
placing needle bar and looper shaft simultaneously and automatically, so that
needles and looper are made to go through the movements required for forming
the stitch in such a manner as to cause the loops formed upon the said two or more
needles, to be taken up or tied by the succeeding stitch, substantially as set forth
and shown in the drawings.
T
L 1
ar
1
1000
CAMBIE & WINCKELSETT,
Warwick Buildings, 40, High Holborn, London, W.C.,
For the Applicant.
CAMBIE & WINCKELSETT,
Warwick Buildings, 40, High Holborn, London, W.C.,
For the Applicant.