Improvements in Feeding Mechanism for Sewing Machines.
Year: 1899

page_text: Date of Application, 10th Mar., 1899 - Accepted, 13th May, 1899
Communicated from abroad by THE SINGER MANUFACTURING COMPANY, of New
York, United States of America, Sewing Machine Manufacturers.
Improvements in Feeding Mechanism for Sewing Machines.
I. JOHN KING MACDONALD, Manager of The Singer Manufacturing Company,
Kilbowie, Dumbartonshire, 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 relates to that form of sewing-machine feeding-mechanism
which has long been in use in the well-known "Singer" lock-stitch machines,
and in which the forward and backward movements of the feed-bar are imparted
thereto from a rock-shaft arranged beneath the work-plate and operated by a link
or feed-connection which in turn has heretofore been actuated by a cam on the
upper or main shaft working in a yoke or fork with which the upper end of said
link or feed-connection is provided. The movement of the said link or feed-
connection is mainly a vertical one so that there is a limited sliding contact
between the cam and the inner faces of the fork referred to, and this sliding
contact has caused more or less wear of certain parts of the fork and cam.
wear causes a looseness of the parts, which is particularly objectionable in
high-speed machines, as it occasions "pounding" which increases the wear and
looseness, so that, for effective and smooth operation of the machine, a renewal
of the worn parts soon becomes necessary.
This
The object of the present invention is to obviate the difficulty referred to
and thus provide a smoothly operating feeding mechanism, of the class in
question, which will not be subject to the objectionable wear referred to.
This object is secured by providing the main shaft with a feed-operating
eccentric which is encircled by a strap one end of which is jointed to the upper
end of the feed-connection or link, the cam, heretofore used, and the fork at the
upper end of the link or feed connection, being dispensed with.
In the accompanying drawings Fig. 1 is a partial broken-out side view of one
form of a Singer machine embodying the invention, the frame being in section
on line 1-1, Fig. 2; and Fig. 2 is a vertical section on line 2-2, Fig. 1.
A denotes a portion of the arm of the machine and B the rotating main or
driving shaft journalled in the upper part of said arm and provided with a
feed-operating eccentric encircled by a strap C is a rock-shaft arranged
beneath the work-plate and serving to impart the forward and backward move-
ments to the feed-bar D, said shaft having at its rear end an arm c, and at its
forward end a second arm c¹ to which latter the said feed-bar is jointed. E is
the link, or feed connection, to an arm or part e¹ on the upper end of which the
eccentric strap is jointed, at be, the lower end of said link being jointed to the
arme of the shaft C. The link or feed-connection E is joined to the feed-regulating
lever F by a link f in the usual manner. The lever F is pivoted at e on the
stud a within the arm 'A. The feed-bar D receives its vertical or up and down
movements as heretofore from the feed raising and lowering rock-shaft G.

page_text: In the operation of the machine the link or feed-connection E is reciprocated
vertically from the eccentric b to impart rocking movements to the feed-shaft C.
the extent of these vertical movements being varied in accordance with the
position of adjustment of the feed-regulating lever F; by raising the outer end
of said lever the vertical movements of said links, are lessened to decrease the
throw of the feed-bar, the actuating movements of the eccentric b being
converted into increased vibrating or lateral movements of the upper end of said
links, as the vertical movements thereof are decreased, owing to the connection
of said link E with the feed regulating lever through the link f.
From the foregoing it will be apparent that as the eccentric b rotates smoothly
in its strap there will be no sucli wear as has heretofore resulted from sliding
contact between certain limited portions of the operating parts and which has
occasioned wear of certain portions of the cam and fork heretofore employed;
the wear between the eccentric and its strap being practically unappreciable,
because uniform, and being capable of being taken up or compensated for, if
necessary. Furthermore the lubricating oil is much better retained in the
eccentric strap than in the yoke heretofore employed, and thus tendency to wear
is further lessened.
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:-
1. In a sewing machine feeding mechanism, the combination with an upper
main shaft, as B, provided with an eccentric, of a feed-operating rock-shaft C
having at its rear end an arm and at its forward end an arm c¹, a feed-bar
jointed to the said arm c¹, the rigid link E jointed at its lower end to the said
arm c, a strap encircling said eccentric and jointed to the upper part of said
link E, the feed regulating lever F, and the link f jointed to said lever F and
link E.
2. In a
sewing machine feeding mechanism, the combination with an upper
driving shaft, as B, provided with an eccentric b, of a feed-operating rock-shaft C
having arms e and c, a feed-bar connected to said arm cl, the rigid link E jointed
to said arm and having at its upper end an arm e, a strap encircling said
eccentric and jointed to the said arm el, the feed regulating lever F, and the
link jointed to said lever F and link E.
Dated this 9th day of March 1899
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents, 62, Saint Vincent Street, Glasgow,
Agent for the Applicant.