IMPROVEMENTS IN SEWING MACHINES
Year: 1883

page_text: LETTERS PATENT to John William Post of the city county and state of New
York in the United States, of America for an Invention of "IMPROVEMENTS
IN SEWING MACHINES
"
COMPLETE SPECIFICATION filed by the said John William Post at the Office
of the Commissioners of Patents on the 17th July 1883.
JOHN WILLIAM POST of the city county and state of New York in the United
States of America IMPROVEMENTS IN SEWING MACHINES.
The object of this invention is to produce a sewing machine which shall be free
from irregular motions, and which shall be capable of forming a lock stitch or the
chain stitch and the number of parts of which the machine is composed is greatly
lessened and which is easily operated and substantially noiseless in its functions.
The invention consists essentially in the improvements which I shall hereinafter
fully describe and which are shown in the accompanying drawings in which;
Figure 1 is a side elevation and Figure 2 a bottom plan view of a machine
provided with my improvements. Figure 3 is a longitudinal section of the same.
Figure 4 is a cross section on an enlarged scale in line xx Figure 2 with the looper
removed. Figure 5 is a partly sectional front elevation of the feed plate and
connecting parts. Figures 6 and 7 are cross sections in lines x x and y y Figure 4
respectively. Figure 8 is a partly sectional front elevation. Figure 9 is a vertical
cross section in line y y Figure 3 looking forward, Figure 10 is a front elevation of
the face plate at the head of the machine. Figure 11 is a horizontal section on an
enlarged scale in line xx Figure 8, Figure 12 is a top plan view of the upper end
of the guide of the needle bar, Figures 13 and 14 are horizontal sections in lines xx
and yy Figure 1 respectively Figure 15 is a side elevation of the needle guard.
Figure 16 is a longitudinal section of the lock stitch mechanism on an enlarged
scale, Figure 17 is a front elevation of the needle bar and lock stitch mechanism
showing the parts in the position in which the hook of the revolving looper seizes'
the loop, Figure 18 is a front elevation of the same parts showing the same in the
position in which the needle thread is drawn off to its greatest length. Figure 19'
is a similar front elevation showing the loop drawn off the hook of the looper.

page_text: Figures 20, 21, and 22 are vertical longitudinal sections of the upper portion of the
needle bar and guide corresponding respectively with Figures 17, 18 and 19,
Figure 23 is a partly sectional top plan view of the lock stitch mechanism and
connecting parts on an enlarged scale, Figure 24 is a horizontal section of the same
parts Figure 25 is a front elevation of the revolving looper. Figure 26 is a side
elevation of the same, Figure 27, is a front elevation of the spool holder, Figures 28
and 29 are vertical sections of the spool holder, at right angles to each other,
Figure 30 is a rear elevation of the arm bearing against the front side of the spool
holder, Like letters of reference refer to like parts in the several figures. A is the
bed or base plate of the machine, A¹ the standard, A² the arm extending forwardly
from the upper end of the standard and A³ the head block arranged in a well
known manner with the exception that the body of the standard A¹ and the arm A²
are inade round in cross section so that it can be readily turned off and prepared
for the operation of plating thereby doing away with the great amount of manual
labor otherwise required for finishing these parts. a is the horizontal driving
shaft in the arm A² and provided at its front end with a crank disc a' by which
the needle bar a² is operated, a³ is a connecting rod connected to the crank pin of
the disc a' and to a cross head or sleeve a respectively. The sleeve is secured to
the needle bar a² by set screws see Figures 3 and 8 or in any other manner, The
needle bar a² is guided at the upper end of the head A³ in a cylindrical bearing a
and at the lower end thereof in a similar bearing aa and a represent the
presser foot and its bar or rod respectively The bar a' is also guided in the top
and bottom of the head block A³, The cross head a surrounds the needle bar a²
and is provided at the side adjacent to the presser foot bar a with a semi cylin-
drical bearing surface which bears against the inner side of said bar. a7 and serves
to guide the cross head on the same thereby giving the needle bar a bearing inter-
mediate between the top and bottom portions of the head block A³. The cross
head a is readily constructed by forming a cross head twice as long as necessary
and drilling three holes, through the same at equal distances apart and then
driving the cross head centrally through the middle opening, whereby two cross
heads of similar form will be formed.
A4 is the face plate of the head block As, This face plate is provided with an
opening a which is covered by a glass a placed opposite the crank disc a' so that
the head motion can be observed through this glass thus facilitating the
application of oil and the taking up of lost-motion through an opening in one of
the side walls of the head block A³, b is the needle secured to the lower end of the
needle bar a² in any well known or desired manner, 61 represents a shield or
guard which is arranged in front of the needle so as to hide the needle bar from
the view of the operator to relieve the eyes from the unpleasant sensation and
dazzling effect caused by the rapid reciprocation of said bar. The shield may be
secured to the head block A³ by a shank 62 inserted in an opening in the head
frane and secured therein by a set screw ba the shield being pivoted to the
shank b2 by a hinge 6 so that the shield can be swung out of the way to expose
the needle when necessary to thread it or for other purposes, The shield 6' also
protects the needle against breakage by preventing obstructions from coming in
contact therewith from the side on which the guard is arranged, the other side
being protected by the presser foot c is the spool post secured to the standard A¹
and c¹ is the spool thereon. d is the tension disc arranged on one side of the
needle bar guide D at the upper end of the head block A³ and d' is a spring that
presses the disc d against the flat side of the needle bar guide D, The spring d
is preferably a long flat spring secured at its lower end to the inner side of one
of the side walls of the head block A3 and made adjustable near its upper
end by a set screw d² (see Figure 8,). The great length of this spring
permits of a very fine adjustment of the pressure, against the tension disc d,
e is a vertical slot or mortise formed in the needle bar guide D on its front
side and extending preferably from the top plate of the head block A³ to the upper
end of the needle bar. guide. f is a projection formed on the front side of the

page_text: needle bar a² near its upper end and playing in the mortise e. The projection f
has in its upper surface a depression or groove f¹ in which the thread rests when
the needle bar rises and completes the stitch in sewing the chain stitch The
front side of the projection is made inclined forwardly and the front side of the
needle bar guide D is also inclined forwardly as shown at f' on both sides of the
mortise e The inclined front portion of the needle bar guide D projects further
forward than the projection f on the needle bar so that as the projection descends
between the inclined portions of the guide D the latter will draw forward the
thread which rests against the under side of the projection f in sewing the lock
stitch and will finally withdraw the thread from under said projection and release
it therefrom.
The needle har guide D has a collar g above the tension disc d that extends
beyond the mortise e which latter extends through this collar, g¹ and g² are notches
formed in the collar g on opposite sides of the mortise e The notch 92 has a tension
bolt g³ arranged in a socket in the collar g and provided with a tension spring g¹
which can be adjusted by means of a screw g³ whereby the thread is steadied or
held against any flopping movement. In sewing the chain stitch the thread runs
from the spool c' to the tension disc d thence upward through the notch g¹, thence
across the upper side of the collar g and the notch in front of the needle bar to the
notch g2 thence downward and through a guide eye on the front side of the
needle bar guide D. and thence downward through the eye of the needle as shown
in Figures 1 and 8, In sewing the lock stitch, the thread runs from the tension
disc d over a horizontal loop h' arranged on the front side of the needle bar guide D
below the collar g and thence downward to the guide h and the eye of the needle.
as shown in Figures 17, 18 and 19. The looper and feed mechanism are actuated
by a horizontal shaft i supported in suitable bearings ¹ formed on the underside
of the bed plate A. Motion is imparted to the shaft i from the driving shaft a by
an eccentric 12 on shaft a and an eccentric rod 23 connected at its lower end to a
crank disc mounted on the end of the shaft i. The eccentric rod 3 rocks on a
fulcrum pin secured to the standard A³, j is an opening formed in the front wall
of the upper portion of the standard provided with a removable cover j¹ which can
be taken off for oiling and adjusting the eccentric and the eccentric rod
attached thereto, K is the rotating looper employed for forming the chain stitch.
The looper K has a shank which is inserted in a socket k¹ formed in the shaft i
and secured thereto by a set screw 2 having a suitable handle and engaging in
a groove or against the flattened side of the inner portion of the shank / so that
the looper can be readily secured in place and removed as may be required,
7 represents an eccentric neck formed at the front end of the shaft i for actuating
the feed bar L. The eccentric is made smaller in diameter than the shaft i and
engages in an elongated opening formed in the feed bar L. The latter is.
provided with the usual serrated surface 12 which projects upward, through an
opening in the bed plate A, In the rear end of the feed bar is formed a notch 24
and is a horizontal bolt in a casting m. formed on the underside of the bed
plate A. The bolt extends through the notch in the feed bar and supports the
rear end thereof. The opening in which the eccentric works is bushed with a
metallic split ring 1 conforming to the contour of opening and one or more
screws pass through the feed bar L and impinge against the bushing 16 as shown
at Figure 5 whereby any wear of the eccentric or bushing may be taken up or
compensated for by the contraction of the bushing through the medium of the
screws in an obvious manner; An adjustable wedge M is arranged on the under-
side of the bed plate A between the rear end of the feed bar L and the depending
side flanges m² on the bed plate A When the feed bar L has been retracted it
rests with its rear end against the wedge M as shown in Figure 5. By
adjusting the wedge M in one or the other direction the feed bar can be
moved forward or backward, thereby changing the starting point and reducing
or increasing the throw of said bar and the length of the stitch. A spiral
or other suitable spring m² is interposed between a shoulder on the casting m and

page_text: a shoulder near the rear end of the feed bar so as to press the feed bar backward,
The rotation of the eccentric effects the forward movement of the feed bar during
which the spring m² is compressed and the reaction of the spring effects the return
movement of the feed bar. The wedge M is provided with a rod m³ extending
along the lower side of the bed plate A said rod having at its rear end a bolt m*
which extends through a .slot mo in the bed plate the bolt being clamped in any
desired position by a thumb nut m The wedge M is adjusted by moving the
bolt min one or the other direction in the slot m³. On the under side of the
bed plate A in front of the looper K is arranged a plate N that serves to confine.
the outer portion of the loop of the needle thread, causing. it to he thrown off on
the inner side of said needle where it can be seized by the hook of the looper K.
The plate N is mounted upon the end of a lever n which is pivoted at n¹ to the
underside of the bed plate A and is provided at its opposite end with a thumb
picce n² for conveniently taking hold of it.
The lever n is made sufficiently elastic to permit it to be locked in position by
the engagement of a small stud or protuberance n³ on the under side of the bed
plate in corresponding openings in the end of the lever m The plate N can be
readily swung away from the looper K when the latter is to be removed from the
shaft i, O represents the disc of the looper which is employed in sewing the lock
stitch and which is provided with a shank o¹ constructed in all respects like the
shank hereinbefore described which is formed on the looper K and whereby the
disc is secured to the shaft i. The disc O is provided on its face side with a
concave depression o² in which the convex rear side of the spool holder P is seated.
A. hook o³ formed on the face of the disc O takes the loop from the needle and a
curved arm of is secured to the face side of the disc O and arranged in front of the
book o³ with its face end near the point of said hook o³ as clearly represented in
Figures 25 and. 26. The spool holder P is constructed with a convex rear side and
V shaped annular edge surrounding the open front. The spool p is constructed
with convex inner and outer sides or discs p² p² and turning on a hollow arbor p³
which is secured to the rear wall of the spool holder P, An annular frame Q bears
against the front side of the spool holder P and confines the latter in the concave
depression of the disc O. The holder P has a lip or projection p* which engages in
a notch
formed in the annular frame Q whereby the spool holder is prevented
from turning in the disc O. Through an opening or recess p³ in the peripheral wall
of the spool holder the thread is drawn and a wire or bar p6 is arranged in said
opening or recess to give tension to the thread by winding the thread around said
bar as represented in Figure 28. A spring q2 or yielding arm is secured to the
shank q3 of the frame Q and bears against the front side of the spool with sufficient
force to retain the spool in its proper position and at the same time permit it to
turn as the thread is drawn off. The shank q3 of the frame Q is attached to a
bracket R depending from the base plate A of the machine by a bolt which is
seated in a socket in. the bracket R and has at its inner end a notch forming a
hook which can be engaged behind a transverse bolt 2 secured in said bracket
and intersecting the socket in which the bolt is seated so that by giving the
bolt a quarter turn in one or the other direction by means of the handle the
bolt is locked or unlocked and the annular frame Q attached or released as may be
desired. While I have shown a desirable means of securing the frame or holder in
place as just described, it will be, apparent that changes may be made in this
particular without departing from the spirit of my invention, so long as the idea is
preserved of securing the frame or holder in place by a partial rotation only of the
locking device such for, instance as that known as a "bayonet joint" Upon removing
the annular frame the spool holder P and the disc O can be removed from the
shaft i and the looper K substituted for the same. It will be observed that the shanks
and o of the loopers K and O respectively are each formed with a flattened side
which is so arranged that when the screw 2 projects slightly within the socket k¹
said shanks can only be inserted when their flattened sides are turned towards said
screw. These flattened sides are so arranged axially relative to the hooks of the
-

page_text: loopers as to ensure the sitting of said loopers in their proper operative positions.
without any special care on the part of the operator. In sewing the lock stitch,
the looper, spool holder P and annular frame are arranged in position as
represented in Figure 17. The loop thrown off by the needle is seized by the
hook o of the looper and during the rotation of the latter in the direction of the
arrow in Figure 17 the loop is gradually enlarged and carried onward, the outer
portion of the loop passing between the front side of the spool holder P and the
frame and the rear side of the loop passing between the rear side of the
spool holder P and the disc O until the parts reach the position represented
in Figure 18. When the descending movement of the needle bar begins,
the projection fat the upper end of the needle bar begins to depress that portion of
the thread which extends across the loop and the continuation of this movement
of the projection f draws the loop from the hook o³ of the looper as represented in
Figure 19. In this manner the needle thread is looped around the thread coming
from the spool in the spool holder P. The curved arm o' is located in close.
proximity to the front side of the needle and prevents the loop of the needle thread
from being thrown off on the front side of the needle, but compels it to be formed
on the rear side in the path of the hook o³. Said arm of also serves to keep the
loop of the needle thread which has been drawn from the hook o³ out of the way.
of said hook until it has been drawn up and tightened by the formation and
enlargement of the next succeeding loop. The front plate of the spool p is provided
with one or more openings s through which the amount of thread contained in the
spool can be observed without removing any part of the mechanism. My improved
machine is free from irregular motions and is therefore easily operated with very_
little effort at a high rate of speed and its operative parts move with very little
noise. The machine can be readily adapted to sew either a chain or lockstitch
without requiring the use of either a screw driver or a wrench for this purpose.
By avoiding the use of an independent take up for taking up slack loops and by
paying the thread for each successive stitch directly from the spool and drawing it,
tight only at the point of finishing each stitch the friction on the thread is greatly
reduced and the liability of the thread being broken considerably lessened, As a
very light tension is sufficient the wear on the thread is avoided and the seam
accordingly strengthened. It will be observed that instead of using the rotary.
looper described for making the lock stitch a rotary shuttle could be employed by
making only such changes as would be apparent to any one skilled in the art, the
gist of my invention in this particular consisting in the generic idea of employing.
interchangeable rotary devices for forming the two kinds of stitches. It will be
understood that what is meant by the interchangeability of the devices designed to
be secured to the end of the rotary shaft beneath the bed plate is that both are so
organized and constructed as to be attached to and removed from the end of the
shaft, and that each is removed to make place for the other in converting the
machine from a lock stitch to a chain stitch and vice versa, What I claim as new
and desire to secure by letters patent is :-
1st The combination in a sewing machine with a needle and its operating
mechanism of interchangeable rotary devices cooperating with said needle to form.
different kinds of stitches substantially as set forth.
2nd The combination in a sewing machine with a needle and its operating
mechanisin, of interchangeable rotary devices cooperating with said needle in
forming different kinds of stitches said interchangeable rotary devices being both
constructed to operate on the same side of the needle substantially as set forth.
3rd The combination in a sewing machine of a needle and its operating
mechanism a revolving shaft provided at its front end with suitable means of
attachment and interchangeable rotary devices for forming different kinds of
stitches adapted to be secured to said shaft, the said interchangeable devices being
so constructed that when seated on the end, of the shaft their proper adjustment
relatively to the needle is secured substantially as set forth. 4th The combination,
in a sewing machine with a needle and its operating mechanism of interchangeable,

page_text: rotary devices adapted to cooperate with said needle in forming different kinds of
stitches and a thread controlling mechanism adapted to coact with either of said
interchangeable devices in forming said different kinds of stitches substantially as
set forth.
"
5th The combination in a sewing machine of interchangeable rotary lock and
chain stitch loopers, and a thread controlling mechanism adapted to draw the
thread from the hook of the lock stitch looper at the proper moment, or to serve
as a take up in connection with the chain stitch looper accordingly as one or the
other of the loopers is used substantially as set forth. 6th The combination in a
sewing machine of a needle operating mechanism arranged above the bed plate, a
rotary shaft arranged beneath the bed plate and rotary devices adapted to be
interchangeably secured to or carried by said shaft for cooperating with
the needle in forming either lock or chain stitches substantially as set
forth. 7th The combination with a reciprocating needle bar and a revolving
shaft provided at its front end with suitable means of attachment, of the
lock and chain stitch loopers adapted to be interchangeably secured to said
revolving shaft substantially as and for the purposes set forth, 8th In a convertible
sewing machine adapted for use with either a revolving chain stitch looper or a
revolving lock stitch looper, the rotary shaft i provided with an axial slot or
socket K' and a set screw K2, the latter projecting slightly within said socket in
combination with the looper shanks provided at their ends with a grooved or
flattened surface whereby the proper adjustment of said loopers with reference to
the needle is secured as herein before set forth, 9th The combination in a sewing
machine of a rotary driving shaft arranged above the bed plate a needle bar con-
nected with and operated by said driving shaft a counter rotary shaft arranged
beneath the bed plate, mechanism for operating said counter shaft from said
driving shaft and interchangeable rotary devices adapted to be carried by 'or secured
to said counter shaft for cooperating with the needle in forming either lock or
. chain stitches at the will of the operator substantially as set forth, 10th The
combination in a sewing machine with a needle and its operating mechanism of a
rotary device adapted to press slightly against the sides of said needle when it
descends below the work plate to insure the formation of loops of needle thread,
and a rotary device cooperating with said needle in forming the stitches for seizing
and expanding said loops substantially as set forth. 11th The combination with
the revolving chain stitch looper of a reciprocating needle bar provided with a
projection which raises the thread and draws it tight in finishing the stitch and a
mortised needle bar guide in which the needle bar projection plays as set forth.
12 The combination with a revolving lockstitch looper and spool holder of a
reciprocating needle bar constructed with a projection which depresses the thread.
and draws the loop from the hook of the looper as set forth, 13th The construction
and arrangement of the mechanism for operating the needle bar from the main
driving shaft and their combination with the presser foot to produce the results
described as specified 14th A screen or shield to cover the needle bar from view or
expose the same to view and its combination with the head block to which it is
removably connected in the manner substantially as specified. 15th The mortised
needle bar guide in combination with a needle bar having a front projectio:
operating in the mortise of the guide constructed as described for the purposes set
forth. 16th The combination with the mortised needle bar guide and a collar
having thread. notches as described of a needle bar provided with a projection
having a depression in its upper side substantially as set forth. 17th The combi-
nation with a mortised needle bar guide of a tension disc, a guide, a loop extending
across said mortise and a needle bar provided with a front projection for the
purposes set forth. 18th The means for steadying the thread consisting of a spring
bolt in combination with the notched collar as described. 19th The means sub-
stantially as shown and described for regulating the tension of the thread consisting
of a lenf spring and its arrangement on and combination with the head block and
tension disc, as described, 20th The peculiar construction and combination of

page_text: operating mechanisın for the feed bar and the means provided for compensating
the wear of said part by means of the split bushing as described and shown,
21st The combination with the lower driving shaft of the lock stitch looper secured
thereto and constructed with a hook and curved arms, a spool holder seated in the
front side of the looper and an annular frame bearing against the front side of the
spool holder for the purposes set forth. 22 The combination with the lock stitch
looper, spool holder and spool of an annular frame attached to a depending bracket
by a bolt having a hook end and adapted to engage behind a transverse bolt and
provided with an operating handle for the purposes as shown and described.
23rd The combination with a removable holder for sustaining the bobbin that
carries the lower thread of mechanism constructed to secure said holder to its
support or detach it therefrom by a partial rotation only substantially as set forth.
24th The mechanisin for confining the spool holder in place in combination with a
rotary bolt adapted to be locked, and unlocked by a quarter turn of said bolt as
shown and described. 25th A spool holder provided with a spool and an opening
or recess through which the thread passes from the spool and a bar arranged in
said opening or recess around which the thread is wound for giving tension to the
same substantially as set forth.
.
26th In a sewing machine a head block constructed with a transparent face
plate through which the head motion can be observed substantially as set forth.
27th The combination with the revolving chain stitch looper of a removable plate
arranged in front of the looper whereby the thread is confined and the loop
prevented from being thrown out on the front side of the needle substantially as
set forth
28th The revolving lock stitch looper provided with a curved arm constructed
as described and arranged relatively as set forth to the hook and the plane in
which the needle moves whereby the loop drawn from the hook is kept out of the
way of the same and the succeeding loop formed by the needle is prevented
from being thrown out or formed on the front side substantially as shown and
described
In witness whereof I the said John William Post have hereunto set my
hand and seal this sixteenth day of July in the year of our Lord One thousand
Eight hundred and Eighty three.
Witness
DENIS DONOHOE
H. M. Consul.
JOHN WILLIAM FOS (L.S.)