Improvements in Sewing Machines.
Year: 1891

page_text: Date of Application, 3rd. Nov., 1891-Accepted, 12th Dec., 1891
COMPLETE SPECIFICATION.
[Communicated from abroad by THE SINGER MANUFACTURING COMPANY, of
New York, in the United States of America, Sewing Machine Manufacturers.]
Improvements in Sewing Machines.
I, ALEXANDER ANDERSON, Manager of The Singer Manufacturing Company's
Works, Kilbowie, Dumbartonshire, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, as communicated to me to
be particularly described and ascertained in and by the following statement :-
My invention has for its object to provide a take-up for sewing machines which
may be operated by a rotating crank pin and still be properly timed so as to let
off the thread slowly and take it up quickly, thereby avoiding the use of a cam-
operated take-up and the objectionable wear and friction incidental thereto, while
securing all of the advantages thereof as to timing and positive action.
To this end my invention consists of a bell-crank lever one arm of which is
jointed to a rotating crank-pin, the other arm of said lever being jointed at its
angular portion to one end of a link, the other end of said link being connected
with a stationary pivot pin, all as will hereinafter be more fully set forth.
In the accompanying drawing
"
Fig. 1 is a front elevation of a "Singer sewing machine with my improved
take-up applied thereto and with the cap or face plate of the head removed.
Fig. 2 is a view similar to Fig. 1, but with some of the parts in different
positions.
Fig. 3 is a front end view of the head of the machine but with certain parts
omitted.
Fig. 4 is a side view of the machine, partly in section.
Fig. 5 is a plan view of the head and forward part of the machine, with the
framework thereof in section.
Figs. 6 to 11 inclusive are detached detail views of parts constituting the take-up
and its operating mechanism.
A denotes the work plate and 13 the bracket arm of an ordinary "Singer"
sewing machine. Journalled in the upper portion of said bracket arm is a driving
shaft C provided at its rear end with the usual fly and pulley wheel D and having
at its forward end a crank disc E provided with a crank pin e to which is connected
a pitmanf which serves to operate the needle bar g.
The crank pin e, as herein shewn, has an integral arm or extension e¹ provided
with a second crank pin e³. Pivoted on a pin secured in the forward end of the
bracket arm B, is a link i, to which is pivotally attached, at its angular or middle
portion, a bell-crank lever the lower arm of which is jointed to the crank pin e²
and the upper arm of which extends outward and is provided at its free end
with a thread-receiving eye k', the said upper arm thus forming the take-up
proper.
By constructing the take-up lever in the form of a bell crank lever and mounting
it on a link connected to the stationary part of the machine and then operating it
by a rotating crank pin, the said take-up lever is given a peculiar movement in
that it moves bodily up and down with the swinging end of the link by which it
is carried, and it is also vibrated on its pivotal connection with said link. As a
result of this construction and arrangement of parts the take-up arm of the said
lever is caused to descend slowly during about three quarters of the revolution of

page_text: its operating crank pin and then to quickly ascend during about the remaining quarter
of said revolution to perform its take-up movement to tighten the stitch. Figure 1
represents the take-up lever at its extreme upper position and during nearly a
half revolution of the crank pin, from the position shewn in Fig. 1 to that
indicated in Fig. 3 the take-up lever is descending bodily. Fig. 3 represents the
take-up operating crank pin at its lower position from which point it begins to
move upward but in doing so, it causes the take-up lever to vibrate on its central
pivotal connection with the link, and thus whlie the operating crank pin has
commenced to ascend the take-up arm still continues to move downward, until it
has reached the position shown in Fig. 2 during the next quarter of a revolution or
from the position shewn in Fig. 2, to that shewn in Fig. 1 the take-up lever has
bodily moved upward and is vibrated on its pivot so that the upward movement
by the take-up arm of said lever is completed in about one-third of the time
occupied by its descent, or during about a quarter revolution of its operating
crank-pin.
'
From this it results that I am able to secure a properly timed take-up lever
which will let off the thread slowly during the time the needle bar is descending,
and while the shuttle is passing through the loop of needle thread, and which will
then quickly perform its take-up movement to tighten the stitch before the eye of
the needle again enters the fabric. Moreover, the positions of the parts are such
that at the moment when the stitch is being tightened the take-up operating crank
pin is passing over the upper part of the circle in which it rotates, and the lower
arm of the take-up is nearly vertical.
The take-up is at this moment, therefore, being vibrated on its pivotal
connection with the link, thereby affording a strong leverage so that any desired
strength of pull on the thread is afforded without strain on the running parts of
the machine.
It will thus be apparent that by the simple mechanism above described I am
enabled to provide a suitably timed take-up which is operated from a rotating
crank pin, and which is therefore well adapted to high speeds, as it may be
operated with comparatively little power and friction.
The timing of the take-up movements may be varied to adapt my improved
take-up for operation in connection with different forms of lower stitch forming
mechanisms from the oscillating shuttles herein shewn simply by varying the
relative position of the stationary pivot to which the link is secured; by changing
the length of the lower arm of the take-up or by changing the position of the
take-up operating crank pin.
66
"
Although I have herein shewn a secondary crank-pin for operating my improved
take-up in its particular relation to the shuttle mechanism of a Singer
oscillating shuttle sewing machine, it will be understood that this secondary crank
pin may not be necessary with some other machines, but that the same crank pin
by which the needle bar pitman is operated may also serve to operate the take-up;
and I do not, therefore, wish to be understood as limiting my invention to the
specific arrangement and proportions of parts herein illustrated."
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
I declare that what I claim is :
1. A sewing machine take-up mechanism consisting of a bell crank lever one
arm of which is provided with a threaded eye, a link which is pivoted at one end
to a stationary part of the machine, and to the other end of which the central or
angular portion of said bell-crank lever is jointed, combined with a rotating crank
pin to which the other or lower arm of the said bell-crank lever is connected.
2. In a sewing machine, the combination, with a rotating crank, provided with
a secondary or off-set crank pin, of a needle bar operated by the first named
crank, a bell-crank lever take-up operated by said secondary or off-set crank-pin,

page_text: and a link, one end of which is connected to a stationary part of the machine, and
to the other end of which the angular or central portion of said take-up lever is
pivoted, substantially as set forth.
Dated this Second day of November 1891.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.