Improvements in Thread-feeding Mechanism for Sewing Machines.
Year: 1890

page_text: Date of Application, 20th Feb., 1890-Accepted, 16th Aug., 1890
COMPLETE SPECIFICATION.
Improvements in Thread-feeding Mechanism for Sewing Machines.
I, ALEXANDER JAMES ELI, of the firm of Hughes, Eli and Hughes, of 76 Chancery
Lane, London, W.C., Patent Agents and Engineers, do hereby declare the nature
of this invention (a communication to me from abroad by Ebenezer Baker Welch of
186 Main Street, Cambridge, State of Massachusetts, United States of America,
Gentleman) 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 provide improved means for automatically
pulling thread from the supplying bobbin or spool of a sewing machine, and feeding
it forward to the stitch forming mechanism at a rate directly proportioned to and
governed by the speed of the machine.
The invention has also for its object to enable the rate of the feeding of the thread
to be varied by the operator, and finally to provide means whereby the thickness of
the work or material being stitched by the machine may be caused to regulate the
rate of the feeding of the thread. To these ends my invention consists in the pro-
vision of two rolls positively rotated by the power which drives the machine, and
arranged to pull the thread from the supply bobbin, and feed it forward to the needle.
The invention also consists in the form of the rolls whereby they are enabled to feed
the thread faster or slower accordingly as the thread is adjusted between the grasping
surfaces. Also in the provision of an adjustable thread guide whereby the thread may
be adjusted between the rolls. Also in providing one of the rolls with a yielding
movement toward the other roll, whereby the rolls are enabled to grasp different
thicknesses of thread. Also in the provision of means for varying the approach of
the yielding roll toward its companion, so that the rolls may be prevented from
exorting their full pressure on coarser threads; and finally in the provision of means
whereby the adjustable thread guide is automatically adjusted by variations in the
thickness of the material under the presser foot, all of which I will now proceed to
describe and claim.
Of the accompanying drawings forming a part of this specification,
Figure 1 represents a side elevation of a sewing machine provided with my
improvements.
Fig. 2 represents a section on linex & Fig. 1.
Figure 3 is a spring for taking up slack.
Fig. 4 represents a perspective view of the adjustable thread guide.
The same letters of reference indicate the same parts in all the Figures.
In the drawings-
:
a a represent a pair of feed rolls located in any suitable or convenient relation to
the bobbin or spool b, which supplies thread to the needle. The roll a is affixed to a
vertical arbor c which is journalled near its upper end in a bearing in a projection d
on the arme of the machine while the lower end of said arbor is journalled in a step
formed on the bed of the machine. The arbore is provided with a pinion meshing
with a worm wheel g on the driving shaft of the machine. The arbor c and its roll
are thus positively rotated at a rate of speed corresponding to the rate of rotation of
the driving shaft. The rolls are provided with intermeshing gears i i, so that the
roll a' is positively rotated in a direction opposite to the rotation of the roll a.
Thread passing from the bobbin b between the points of closest approach or in other
words the grasping points of the rolls a a', will be steadily drawn from the bobbin
and allowed to pass to the stitch forming mechanism at a fixed rate corresponding to
the rate of operation of said mechanism, hence the tension of the thread between the
rolls and the needle will always be substantially uniform and as the stitch forming
mechanism does not pull off the thread, no variation in the tension will occur.

page_text: excepting in case an oscillating hook is employed as a part of the stitch forming
mechanism, when a
slight variation will occur, the thread being slightly slackened
when the hook is in certain positions. To overcome this slight variation I provide a
spring or spring arm k, on the face plate or end of the arm e, the free end of said arm
having a hook or orifice through which the thread passes and being adapted to deflect
the thread between the guide 1 through which it passes from the rolls a a¹ and the
eye of the needle, and exert a constant yielding pressure on the deflected portion of
the thread, thereby preventing even the slightest variation in the tension.
The arbor m of the roll a is pivoted at n to the projection or support d, and is
provided with a yielding movement toward the roll a by means of a spring o secured
to a part of the fixed support, and to a shank formed on the arbor m and extending
below the pivot n. The roll a is thus caused to bear with a yielding pressure against
the roll a, so that different sizes of thread may be grasped with equal facility. The
roll a' may be prevented from pressing against the roll a along its entire length, or in
other words the approach of the roll a to the roll a, may be regulated by any suitable
'means so that when the rolls are used with coarse threads the roll a¹ may be prevented
from meeting the roll a with the full pressure of the spring o, so that the thread will
not be unduly compressed by the rolls. To this end the portion of the pivot n that
passes through the arbor m may be eccentric to the part that passes. through the
support d, so that by turning said pivot the relation of the arbor m to the arbore will
be slightly varied as will be readily understood. I prefer to make the rolls a a¹
tapering or frusto-conical in form, both tapering in the same direction, as shown in
Figs. 1 and 2. This form of the rolls enables the thread to be fed more or less rapidly
by causing it to pass between larger or smaller portions of the varying diameters of
the rolls. represents an adjustable guide composed preferably of two connected
arms having eyes s near their ends. One of said arms passes through a socket in the
support d and is secured at any point to which it may be moved by a set screw .
The arms are arranged at opposite sides of the grasping points of the rolls a a¹.
The eyes as receive the thread and by adjusting the arms in the sockets they can
be caused to depress or elevate the thread between the rolls and cause larger or
smaller diameters of the rolls to grasp and feed the thread. The rolls may thus be
caused to supply the thread more or less rapidly according to the requirements of the
work. The thread guider may be adjusted by the operator as required, but if it is
desired to give the guide an automatic adjustment a levert may be employed pivoted
at u to the arm of the machine, and engaged at one end with the guide r, and at the
other end with the presser bar v.
The presser bar is therefore caused to adjust the thread guide r, so that when
thick goods are under the presser foot and the presser har is raised thereby the
thread guide will be correspondingly depressed, and the thread will be supplied more
rapidly than for thinner goods. The engagement of the lever t with the presser bar is
effected in the present instance by means of two pins v¹¹ on the presser bar, between
which the end of the levert projects. Said pins should be sufficiently separated to
prevent the movements of the presser bar caused by the upward and downward
movements of the feed dog from moving the lever t when work of ordinary thickness
is under the presser foot.
I do not limit myself to the details of construction described, and shown, but may
vary the same withont departing from the spirit of my invention.
It is obvious that the described improvement is applicable to any kind of sewing
machine, either lock stitch or single thread and to button hole machines.
I claim―
1. In a sewing machine, a pair of rolls adapted to pull the thread from the
supplying bobbin, a connection with the driving shaft of the machine, whereby said
rolls are positively rotated, and a pivoted bearing or support for one of said rolls,
having a yielding movement toward the other roll, the elements in combination
substantially as set forth.
2. In a sewing machine, a pair of rolls adapted to pull the thread from the

page_text: supplying bobbin, a connection with the driving shaft of the machine, whereby said
rolls are positively rotated, a pivoted hearing or support for one of said rolls, a spring
whereby said pivoted bearing and its roll are pressed toward the other roll, and
adapted to yield and means for limiting the movement of the yielding roll toward its
companion, whereby the rolls are enabled to feed coarse threads without unduly
compressing them, all combined and arranged substantially as set forth.
3. In combination with the driving mechanism of a sewing machine, a pair of
tapered rolls driven thereby, and an adjustable guide whereby the thread may be
caused to pass between the rolls at any desired point.
4. In a sewing machine, the combination of a pair of tapered rolls adapted to pull
the thread from the supplying bobbin, an adjustable thread guide whereby the thread
may be caused to pass between the rolls at any desired point, and automatic mechanism
whereby said thread guide is adjusted by the thickness of the material under the
presser foot, as set forth.
5. In combination with the driving mechanism of a sewing machine, a pair of rolls
driven thereby and adapted to pull the thread from the supplying bobbin and feed it
forward to the needle, and a spring whereby the thread between the feeding rolls and
the needle is kept at a uniform degree of tension, as set forth.
6. In combination with the driving mechanism of a sewing machine, a pair of
thread pulling and feeding rolls, geared together and an arbor secured to one of said
rolls and geared to the driving shaft of the machine as set forth.
7. In a sewing machine, the combination of a pair of thread pulling and feeding
rolls geared together, a positively rotated arbor affixed to one of said rolls, a pivoted
arbor supporting the other roll and its gear wheel, a fixed support for the pivot of the
last named arbor, and a spring connecting the pivoted arbor and its fixed support
whereby the pivoted arbor and its roll are given a yielding movement toward the
other roll, as set forth..
8. The combination with the driving mechanism of a sewing machine, of the
positively rotated thread pulling and feeding rolls having tapered peripheries, and the
connected thread guiding arms, adapted to slide in a fixed socket, and arranged at
opposite sides of the thread grasping points of said rolls, whereby the thread may be
presented to any desired grasping portion of the varying diameters of said rolls, and
fed more or less rapidly, as set forth.
9. The combination of the positively rotated thread pulling and feeding rolls having
tapered peripheries, the connected thread guiding arms adapted to slide in a fixed
socket, and arranged to present the thread to any desired grasping portion of the
varying diameters of the rolls, and a pivoted lever engaged at one end with said
adjustable arms and at the other end with the presser bar, whereby changes in the
thickness of the material under the presser foot are caused to vary the position of the
thread between the rolls, as set forth.
Dated this 20th day of February 1890
HUGHES, ELI & HUGHES,
76, Chancery Lane, London, W.C., Agents for the Applicant.