Improvements in Sewing Machines.
Year: 1892

page_text: 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 invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
66
My invention relates first to that class of sewing machines in which the needle
bar is moved horizontally to cause it to descend in different vertical planes in over-
seaming, working button holes or doing ornamental or fancy stitching; and this
part of my invention has for its object to provide means for preventing the needle
from getting out of time" from the shuttle or looper co-operating therewith,
when wide overseaming stitches are being formed and when the horizontal move-
ments of the needle are very considerable, the needle and shuttle or looper, it being
understood, being operated from a common driving shaft. In machines of the
class referred to, as heretofore constructed, more or less difficulty has been
experienced in forming wide overseams, owing to the fact that the needle, when
working in one or the other of its different planes, would be slightly out of time
from the shuttle or looper, thereby causing liability of skipping stitches, and this
is the difficulty which this part of my invention has for its object to obviate.
The invention also relates to an improved construction of needle bar applicable
both to this class of machines and to machines for ordinary work and in carrying
my invention into effect I provide means for so compensating for the differences of
position of the needle relative to the path of movement of the shuttle or looper
that the eye of the needle will always be at about the same distance below the
point of the shuttle or looper when a loop of needle thread is to be taken in which
ever of its different vertical planes the needle may be working.
In the drawings referring to Sheet 1, Fig. 1 is a sectional side view of an over-
scaming machine embodying the first part of my invention and Fig. 2 is a bottom
view thereof.
Fig. 3 is a front end view of the same with the face-piate removed.
Figs. 4 and 5 are detail horizontal sectional views with the needle bar in different
positions, to show the movement of the compensating mechanism between the
needle bar and its operating pitman.
Figs. 4 and 5 are detail views illustrating the relative positions of the needle
and point of the shuttle when the needle bar is beginning to rise in the different
vertical planes denoted by Figs. 4 and 5, respectively.
Fig. 6 is a diagram to illustrate the different positions of the needle-bar operating
crank-pin when the needle and shuttle are in the positions shewn by Figs. 4
and 5.
Fig. 7 is a diagram to illustrate the relative vertical positions of the centre of
the driving shaft and the centre of the end of the needle bar stud.
Fig. 8 is a detail view to show the connections of the needle bar frame operating
cam with the driving shaft.
A denotes the work-plate, B the bracket arm, C the driving shaft journalled .in
the upper part of said arm and connected by bevel gears c, d with the vertical
shaft D provided at its lower end with the crank d' connected by the pitman with
an arin of a rocking sleeve F having a second arm f¹ provided with flanges
between which is received a stud, on an army of a short vertical shuttle operating
rock-shaft G, said shaft G having at its upper end the shuttle carrier receiving
the oscillating shuttle, H working in the horizontal race. The driving shaft C.

page_text: carries a second bevel gear el meshing with a larger bevel gear formed on a disc !
journalled on a studi and provided in its outer face with a cam groove entered
by a stud on a rocker to which the rear end of the pitman J is adjustably
connected the forward end of said pitman being attached to the rocking needle-bar-
frame K pivoted on the centre screws k. As the cam disc I is geared to the
driving shaft C so as to rotate once while the said shaft turns twice the needle-
bar N, mounted in the frame K and carrying the needle n, will be caused to descend
in different vertical planes alternately, said needle bar being connected by the
pitman L with the crank-pin carried by the disc on the forward end of the
shaft C.
The mechanism thus far described is common to the well known "Singer" over-
seaming machine in which, as heretofore constructed, the block m to which the
needle-bar is attached, has a long stud loosely entering a hole in the lower end of
the pitman Laud which stud merely slid back and forth in its bearing in the pitman
as the needle bar was moved in and out or reciprocated horizontally, said stud
remaining at all times parallel with the longitudinal axis of the driving shaft C.
In the present instance the block m is provided with a rearwardly extending fork m¹
embracing a stationary rod O fixed in the head of the machine, and the said block
carries a stud m², as heretofore, excepting that said stud is furnished at its end with
a ball which enters the aperture in the lower end of the pitman L and which thus
permits said stud to rock without binding in the pitman. Thus as the needle-bar is
moved in and out to descend in its different vertical planes, the stationary rod O
embraced by the fork m¹ of the block m, will cause said block to rock horizontally
and thus the stud m" will swing back and forth from the position shown in Fig. 4 to
the position shown in Fig. 5 and vice versa, the needle har turning in its vertical
bearings in the frame Kas it is rocked back and forth. In other words the block m,
to which the needle bar is attached and which may be said to carry the said needle
bar, is a lever of the 3rd class, the rod O being the fulcrum thereof while the needle
bar, which is carried in and out by the swinging frame K, is the power by which the
said block or lever is vibrated to cause the stud m* to vibrate back and forth
horizontally, the said stud forming an arm converting the said block or lever into
a bell-crank lever.
In the position shown in Figs. 4 and 4 the needle is at its innermost position
(or at its right hand position, referring to Fig. 1) and the shuttle is moving
forward, as denoted by the arrow in Fig. 4, to take the loop of needle thread at
the moment when the needle is beginning to rise. In the position shown in Figs. 5
and 54 the needle is at its outermost position about one fourth of an inch (in
making a rather wide seam) to the left (with reference to Fig. 1) of the position
shown in Figs. 4 and 4 and as the shuttle, when the needle is rising, is moving
forward, as before, its point meets the needle considerably earlier, with reference
to the rotation of the driving shaft, than at the previous stitch. To ensure
certainty of operation and to prevent skipping stitches it is necessary that the eye
of the needle should be just below the point of the shuttle at the moment the
latter reaches the needle, but when the needle has a considerable horizontal move-
ment, as is necessary in making a wide overseam, the variation in the timing of
the. needle and shuttle is so much that unless compensated for, so that the needle
eye will always be at about the same distance below the shuttle point when the
loop is taken, skipping of stitches is liable to occur. Thus if the parts be rightly
timed for the position denoted in Fig. 4 they will be out of time for the position
denoted in Fig. 5 for the reason that when in the latter position the needle should
descend a little earlier (with reference to the rotation of the driving shaft) than
when in the former.
Referring now to Fig. 4 the longitudinal axis of the stud m² is shown to be
parallel with the longitudinal axis of the driving shaft and is central directly
below the same, as denoted by the vertical line dig. 7; but in Fig. 5 the
free end of said stud is further to the right so that its centre with relation to
the centre of the said shait is denoted by the inclined line 5 in Fig. 7. The
7

page_text: needle bar will be at its lowest point in its downward movement when the crank
pin is in the same vertical plane with the ball m³ which forms the connection
between the block m secured to the needle bar and the lower end of the pitman L
by which the needle bar is operated. The ball m³ is shown in Fig. 4 as being
directly central beneath the driving shaft C, but in Fig. 5 it is shown as being
somewhat to the right of the centre of the said driving shaft, the two positions
of the said ball being approximately represented by the diagram Fig. 7. It will there-
fore be apparent that when the needle bar is swung outward, as shown in Fig. 5, and
its point of connection with the pitman L, to wit, the ball m³, is thrown further
to the right, the crank pin e² and the said ball m³ will come into the same vertical
plane earlier in the rotation of the driving shaft than when the stud m² is in
the position denoted in Fig. 4.
From this it results that as the driving shaft is rotating in the direction denoted
by the arrows Figs. 6 and 7 the needle bar will be at its lowest point of descent.
slightly earlier in the rotation of the driving shaft when the stud is in the inclined
position shown in Fig. 5 than when in the straight position shown in Fig. 4; as
the outer end thereof is farther to the right or towards the direction from which
the crank pin is coming. This operation is further illustrated in the diagram
Fig. 6 in which the line 4 denotes the position of the crank pin c with relation
to the centre of the driving shaft when the point of the shuttle meets the needle,
as the latter is rising, when the parts are as shown in Figs. 4 and 4, and the line 5"
denotes the relative positions of the crank pin and centre of driving shaft when
the parts have assumed the position shown by Figs. 5 and 5^. In other words,
by rocking the block m and the stud m² carried thereby back and forth, as
described, the time of the descent of the needle bar with relation to the rotation
of the driving shaft (from which both needle and shuttle receive their movements)
is varied to compensate for the varying positions in the path of movement of the
shuttle at which the point of the latter meets the needle.
It will thus be seen that the horizontally rocking block or lever m and its
operating means, co-operating with the pitman to the lower end of which it is
connected, and with the crank which operates said pitman, constitute compensating
mechanism for keeping the needle and its co-acting shuttle or loop-taking device
in proper time, notwithstanding the horizontal movements of the needle which would
otherwise get the needle and shuttle or looper somewhat out of time; and the term
compensating mechanism " as employed in the claims of this Specification will
therefore be understood to mean a mechanism whereby the otherwise improper
timing of a horizontally moving needle, with relation to the movements of its
co-operating loop taking device, will be compensated for, and the parts be kept
in proper time with each other.
I do not wish to be understood as limiting my invention to the particular
construction of the compensating mechanism herein shown, as the details thereof
may be varied widely without departing from the spirit of my invention.
It will be obvious from the construction shewn by the drawings that the
swinging movement of the stud m² is always in proportion to the swinging move-
ments of the needle bar frame, so that the greater the horizontal movements of
the needle bar the greater will be the swinging movements of the stud m². It will
therefore be understood that my improved compensating mechanism is automatic
or self-regulating in its action so that the time of the beginning of the upward
movement of the needle is varied in proportion to the extent of its horizontal
movements, and thus the eye of the needle will always assume the same, or nearly
the same, vertical position at the moment when the point of the shuttle or looper
is moving forward to take a loop of needle thread, whatever may be the extent of
the horizontal movement given to the needle. Thus, with my improved com-
pensating mechanism applied thereto, an overseaming machine in which the needle
is given wide horizontal movements may be run at any desired speed with no
more danger of skipping stitches than an ordinary family machine.
It is well known to those familiar with sewing machines that a very large part

page_text: of the power required to drive the same is expended in operating the needle bars
thereof, the sudden stopping and starting of the needle bars in their reciprocating
vertical movements requiring when the machines are running at high rates of speed,
considerable power. To obviate this objection it has been proposed to lighten the
needle bars by making them hollow and by running them on internal bearings, but
with the constructions heretofore proposed it has not been found practicable to
employ needle bars of this character for the reason that the internal bearings alone
could not be relied upon to steady the needle bars with sufficient accuracy.
My invention has further for its object to provide a very light needle bar which
is applicable not only to the class of machines herein before described but to
sewing machines for ordinary purposes and which bar may be run with a minimum
of power at high rates of speed it being so steadied and supported that it will operate
in an accurate and reliable manner. To this end my improvement consists in
providing a hollow needle bar, which is preferably made comparatively short, with
both inner and outer bearings arranged as low as is practicable so as to afford
steady and reliable supports for the short, hollow needle bar.
On Sheet 2 of the accompanying drawings Fig. 1 is a front end view of the head
or forward part of the bracket arm of an ordinary sewing machine with this part
of my invention applied thereto, and Fig. 2 is a side view of the same. Fig. 3 is
a detail view of the rod which forms the internal bearing for the hollow needle bar,
and Fig. 4 is a cross-section of the same on line 4-4 Fig. 3. Fig. 5 is a detail
view of the hollow needle bar and Fig. 6 is a detail view of the clamping block
connecting the latter with its operating pitman.
A denotes the head or forward part of the bracket arm of a sewing machine,
B the driving shaft provided with a crank b connected by a pitman with the
clamping block d secured to the hollow needle bar E. F denotes a rod which is
attached at its upper end by a set screw a to the head A in an ordinary machine or
to the upper part of the needle bar frame in the machine illustrated on Sheet 1 and
the lower part of which rod is of a size suitable to enter and closely fit within the
bore or longitudinal aperture in the hollow needle bar E and form a longitudinal
internal bearing for the latter, the lower end of the said rod being preferably
extended below the lower surface of the crosspiece Sheet 2 or below the lower
surface of the needle bar frame Sheet 1 which affords an external longitudinal
bearing for the said hollow needle bar. The lower reduced portion of the bearing
rod F which fits within the hollow needle bar and forms the internal longitudinal
bearing for the latter is preferably provided with a groove which admits of the
ingress and egress of air to the internal aperture of the hollow needle bar when the
latter is in operation, thereby preventing the tendency of the said bar to stick on
said bearing rod by suction. Instead of making this air groove in the bearing rod
it is obvious that one or more slight internal air grooves might be made inside the
hollow needle bar. The internal aperture of the hollow needle bar is preferably
enlarged or flaring at its upper end, as denoted at ein Fig. 5, for the purpose of
facilitating the entrance of oil to lubricate the internal bearings.
It will be obvious by reference to the drawings that the hollow needle bar is of
such a length that when it is in its elevated position its upper end is still below. the
driving shaft B from which it is operated, or in other words that the said bar is
made as short as is practicable for the purpose of making it as light as possible.
By thus providing both external and internal longitudinal bearings for the hollow
needle bar the latter may be made so short that it will be very light, while at the
same time it will be held so steadily that it will operate with as little tendency to
lateral vibration as the long solid needle bars now in use. The lower end of the
rod F Sheet 2 extending through the cross piece a¹ in which the external bearing
for the hollow needle bar is formed both bearings are to a considerable extent, in
the same horizontal plane, or, in other words, the said bearings coincide or overlap
each other. This of course ensures greater steadiness than could be secured if the said
bearings were not thus co-incident, or in the same horizontal plane.
The ordinary solid needle bar of the "Singer" machine now in use: weighs about

page_text: two and a half ounces, while my improved needle bar weighs only about five-eighths
of an ounce. Thus in running a sewing machine having a needle bar weighing two
and a half ounces at the rate of 2500 stitches per minute it is, necessary to start and
stop this weight of two and a half ounces 5000 times, this being equal to lifting a
weight of about 780 pounds (gravity being an inconsiderable factor in the down-
ward movements at high speeds) while as my improved needle bar weighs only
about one-fourth as much as the old needle bars three-fourths of the power
employed in reciprocating old needle bar is saved, to say nothing about the great
saving of power in lessened momentum incidental to the reduced weight.
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. In a sewing machine, the combination with a needle-bar, needle, a loop-
taking device co-operating with said needle, means for reciprocating said needle-
bar and needle both vertically and horizontally, and a driving shaft from which
said needle and loop taking device are both operated, of a compensating mechanism
for causing the said needle and loop-taking device to meet each other carlier in
the rotation of the said driving shaft when the needle is working on one plane than
when it is working in the other, substantially as described with reference to Sheet 1
of the drawings annexed.
'
2. In a sewing machine, the combination with a needle-bar, needle, a loop-
taking device co-operating with said needle, means for reciprocating said needle-
bar horizontally and a driving shaft from which said needle-bar and loop-taking
devices are both operated, of a pitman connected to said driving shaft, and a
horizontally rocking lever carrying said needle-bar and having a stud engaged by
said pitman, substantially as described with reference to Sheet 1 of the accompanying
drawings.
3. In a sewing machine, the combination with a needle-bar and needle and means
for reciprocating the same horizontally, of a horizontally reciprocating shuttle, a
driving shaft from which said needle-bar and shuttle are both operated, a pitman
connected to said driving shaft and a horizontally rocking lever to which said
needle-bar is attached and which is provided with a stud engaged by said
pitman, substantially as described with reference to Sheet 1 of the appended
drawings.
4. In a sewing machine, the combination with the shuttle the swinging needle-bar
frame, the driving shaft and means for operating said shuttle and frame from said
shaft, of the pitman L connected to said shaft, the stationary rod O, and the
rocking lever me having a fork embracing said rod and having also the ball-headed
stud m² entering an aperture in said pitman, and the needle bar attached to said
lever, substantially as described with reference to Sheet 1 of the drawings
annexed.
5. In a
sewing machine, a hollow needle bar having internal and external
longitudinal bearings, substantially as and for the purposes set forth with reference
to Sheet 2 of the accompanying drawings.
6. In a sewing machine, the combination with a hollow needle-bar, and a rod
forming an internal longitudinal bearing for said bar, of an external longitudinal
bearing for said hollow needle bar, substantially as described with reference to
Sheet 2 of the appended drawings.
7. In a sewing machine, the combination with a hollow needle bar and a rod
forming an internal longitudinal bearing for the same, of an external longitudinal
bearing for the said hollow needle bar which coincides with or overlaps a portion of
the said rod forming the internal bearing, substantially as described with reference
to Sheet 2 of the drawings annexed.
S. In a sewing machine, the combination with a hollow needle bar and a rod
forming an internal longitudinal bearing for the same, said rod being provided with
a lougitudinal groove for the passage of air, of an external longitudinal bearing for

page_text: said hollow needle bar, substantially as described with reference to Sheet 2 of the
accompanying drawings.
Dated this Eighteenth day of July 1892.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.