1. * GB780059 (A)
Description: GB780059 (A) ? 1957-07-31
Work-jogging attachment for a sewing machine
Description of GB780059 (A)
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The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
PATENT SPECIFICATION
780,059 Date of Application and filing Complete Specification: Dec.
23, 1955.
Application made in United States of America on Jan. 28, 1955.
Complete Specification Published: July 31, 1957.
Index at acceptance:-Class 112, C2C(2B:5).
International Classification:-DO5b.
COMPLETE SPECIFICATION
Work-jogging Attachment for a Sewing Machine We, THE SINGER
MANUFACTURING COMPANY, of Elizabeth, New Jersey, United States of
America, a Corporation organised under the Laws of the State of New
Jersey, United States of America, do hereby declare the invention, for
which we pray that a patent may be granted to us, and the method by
which it is to be performed, to be particularly described in and by
the following statement:-
This invention relates to ornamental stitch attachments of the

2. work-jogging type for sewing machines and, more particularly, to an
improved operating mechanism for a sewing machine work-jogging
attachment.
It is an object of this invention to provide an operating mechanism
for a work-jogging attachment by which the motion necessary to effect
jogging of the work may be transmitted smoothly and efficiently.
Another object of this invention is to provide an operating mechanism
for a workjogging attachment in which frictional resistance between
the moving parts is minimized so that binding or seizing of the parts
is eliminated.
In the accompanying drawings:Fig. 1 represents a top plan view of a
camcontrolled work-jogging attachment from which the cam has been
removed to expose the actuating mechanism; Fig. 2 represents a side
elevational view of the work-jogging attachment with the cam in
section and portions of the frame and bight control slider broken away
to expose the actuating mechanism; and Fig. 3 is a diagrammatic top
plan view of a portion of the actuating mechanism which co-operates
with the pattern cam. Referring to the drawings, the actuating
mechanism of the present invention is embodied in a work-jogging
attachment according to the co-pending patent Application No. 27708/55
(Serial number 774,268).
The work-jogging attachment comprises a frame 11 which carries a block
12 slotted to [Price 3/61 embrace a sewing machine presser bar 13 to
which the attachment frame 1 1 is secured by a thumb screw 14 in place
of the usual sewing machine presser foot.
Journalled between spaced upstanding 50 arms 15 of the attachment
frame 11 is a stud shaft 16 to which is secured a forked
attachment-actuating arm 17. As is customary in sewing machine
work-jogging attachments, the forked arm 17 is adapted to embrace the
55 usual needle-clamp 18 by which a needle 19 is removably secured in
the extremity of a needle bar 20. Reciprocation of the needle bar is
thus harnessed to oscillate the arm 17.
A lug 21 struck out from the arm 17 is 60 operatively engaged between
spaced upstanding fingers 22 of a slide plate 23 which is constrained
for reciprocation on the attachment frame 11 by a pair of slot-and-pin
connections therewith, as indicated at 24. 65 Pivoted at 25 to the
slide plate 23 is a pawl 26 which is biased by a spring 27 into
engagement with the teeth of a ratchet wheel 28 fast on a cam shaft 29
journalled vertically in the attachment frame. In timed relation with
70 the reciprocation of the needle bar, step-bystep rotary motion in
the direction of the curved arrow in Fig. 3 is thus imparted to a
pattern cam 30 which is keyed to turn with the cam shaft 29. 75 The
pattern cam 30 is formed with a closed sinuous cam groove 31 defined
between an inner side wall 32 and an outer side wall 33, it being

3. understood that the configuration of the cam groove determines the
pattern of 80 work-jogging movements effected by the attachment. The
cam groove, therefore, may be of any selected configuration to produce
with the attachment any desired pattern of zigzag stitches. 85 The cam
groove 31 is tracked by a follower roller 34 which is journalled on a
follower pin 35 fixed to one extremity of a workjogging member 36
which at its opposite extremity carries a work-engaging foot 37. 90
No. 36867155.
780,059 The work-jogging member is formed with an elongated slot 38
which extends lengthwvise between the follower pin 35 and the
workengaging foot 37. Thie slot 38 accommodates a fulcrum pin 39 which
is carried by a slider 40 confined to move along the attachment frame
11. The slider may be shifted along the frame 11 by means of a finger
grip 41 to carry the fulcrum pin 39 to any selected position along the
slot 38. A thumb screw 42 which passes through a slot 43 in the slider
and is threaded into the frame provides a means by which the slider 40
may be clamped in any selected position ofadjustment. Thus, by
changing the ratio of the lever arms presented by the work-jogging
member, the extent of work-jogging movement of the workengaging foot
37 may be adjusted.
Pivoted on the cam follower pin 35 is one extremity of an anchor link
44 of which the opposite extremity is secured to the attachment frame
by a pivot pin 45 which is threaded into a block 46 secured by screws
47 to the frame.
It will be understood that the slot and pin connection 38, 39 between
the attachment frame and the work-jogginig member 36 serves only as a
fulcrum for oscillation of the work-jogging member 36 and does not
dictate the path of motion of the follower pin 35.
The path of motion of the follower pin is limited by the anchor link
44 to an arc of a circle having as its centre the pivot pin 45.
The anchor link 44, therefore, constitutes a cam follower controlling
device since the anchor link controls the path of movement of the
follower pin; the pattern cam also controls the position of the
follower pin along the path. In Fig. 3, the arc of the path of the
follower pin is indicated as M, and in accordance with established
kinematic principles, the path of movement at any instant may be
represented as occurring along a line tangent to the arc M such as the
tangents A and A'.
The instantaneous path of movement of any point on the pattern cam is
likewise capable of being illustrated as a tangent to an arc passing
through the point and having as its centre the centre of rotation of
the cam which is the axis of the cam shaft 29.
The instantaneous path of movement of that point of the pattern cam
which coincides with the cam follower is indicated in Fig. 3 as C.

4. Since rather severe space restrictions exist in sewing machine
attachments of this type, the overall dimensions of the pattern cam
are limited and as a result the characteristics of the inner and outer
cam groove side walls differ markedly. Whereas the curves and slopes
of the outer cam groove side wall 33 are comparatively smooth and
gradual, those of the inner side wall 32 are abrupt and sharply
angled. The actuating mechanism of the present invention is
advantageous in that it limits the path of movement of the cam
follower is such a manier that the outer cam groove side wall is
called upon to impart a proportionately greater share of effort in
jogging the cam foliower, thereby providing 70 for easier and smoother
actuation of the attachment and minimizing the possibility of binding
or jamminug of the parts.
With this object, the pivot pin 45 of the anchor link 44 is positioned
with respect to 75 the frame so as to define a cam follower pin path
M, all parts of which, as illustrated in Fig. 3, are inclined with
respect to the line X-X joining the axis of the cam follower pin 35
and the centre of rotation of the 80 pattern cam.
In the preferred embodiment of the drawings, the inclination of the
cam follower pin path is outwardly from the centre of pattern cam
rotation and in the direction C of 85 pattern cam rotation taken at
the cam follower. Thus, within its range of movement along the patlh
MI. the cam follower pin will at any instant have an instantaneous
path of movement such as A or A' depending, 90 respectively, upon
whether the pin is being moved outwardly by the inner cam groove side
wall 32 or being moved inwardly by the outer cam groove side wall 33.
The path of outward cam follower movement A being inclined in the
direction C of pattern cam movement encourages cam follower movement
in this direction and reduces the effort required by the inner cam
groove side wall 32 to move the follower outwardly. By the same token,
the effort required by the outer cam groove side wall 33 to move the
cam follower ivnwardly is correspondingly increased, however, the more
gradual cam surfaces on the outer side wall 105 are more suitable for
delivering this increased increment of effort and, therefore, it is
advantageous that the inner cam groove side wall be favoured in the
direction of less effort requirements. 110 Since all parts of the cam
follower path are inclined with respect to the pattern cam radius
which contains the cam-follower pin, the jogging motion of the
work-engaging foot 37 will not be symmetrical about the centre 115
line of stitch formation: however, this offset effect will not be
objectionable if the inclination of the cam follower path is kept
within reasonable bounds. For instance, if the maximum error in
symmetry of the 120 jogging foot remains less than the diameter of the
sewing thread, the assymmetrical movement of the foot will nlot be

5. objectionable.
As illustrated in Figs. I and 3, the anchor link 44 is preferably
diposed substantially in 125 continuation of the workjogging member 36
so that the inclinationi of the cam follower path will be small. The
anchor link pivot pin 45 is, however, offset from the line Y-Y, which
passes through the fulcrum pin 39 and 130 follower in a path inclined
with respect to a 25 line joining the centre of the cam follower with
the centre of rotation of said pattern cam.
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