IMPROVEMENTS IN SEWING MACHINES
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by George Walton Baker at the
Office of the Commissioners of Patents, with his Petition, on the
23rd February 1874.
I, GEORGE WALTON BAKER, of the City of Wilmington, in the
County of New Castle and State of Delaware, one of the United States
of America, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SEWING MACHINES," to be as follows:-
My Invention relates to improvements in sewing machines, par-
ticularly applicable to sewing together the edges of wet and untanned
hides and other chemically treated materials, and it consists,-
Firstly. In the general arrangement and combination of the different
parts of a machine, whereby the principal working parts are placed above
the table, whereby the same are out of the way of and are prevented
from being injuriously acted upon by wet or chemically treated hides or
other substances being sewn together thereby.
Secondly. The Invention consists in the means for guiding and

page_text: Iced plate arranged to work in connection WICH VIDrating necure and
cast off.
Fourthly. To improvements in the construction and arrangement of
the brake for the cast off bar.
Fifthly. To improvements in the arrangement and construction of the
cast off.
And Sixthly. To improvements in the tension mechanism.
In carrying out my Invention I employ a frame consisting of a base
and a supporting arm or standard constructed with an elbow, a pair of
arms or forks, and the necessary bearings and perforations to sustain the
working portions of the machinery. The main operating shaft, to which
power is applied, is supported horizontally in bearings carried by the
main portions of the standard. To the end of this shaft an eccentric and
a pair of cams are affixed. One of the cams affixed to the main shaft
is so formed as to operate by means of a friction pulley an arm affixed
to a vertical rod, which is supported with capability of movement in the
frame and table, and extending down beneath the table, where it is
provided with an arm and eye, which serves as a guide and support for
the thread to form the stitches. The cam operating the arm affixed to
the shaft operating the guide and support is so formed as to give an
alternating reverse motion to the guide and support, by which means
the thread is put in proper position to be taken up by the needle.
A vibrating arm is pivotted to the upper and forward portion of the
supporting arm or standard which supports and carries the needle and
cast off bars, and a vibrating shoe which works in a slot in the face
plate affixed to the base of the machine..
The arms or forks of the standard extend forward and at the side of
the vibrating arm, and support the vertical bar of the presser foot, which
is provided with a lifting cam, retaining spring, and a vertically adjustable
arm affixed to the vertical bar in position to be acted upon by one of the
cams to raise the foot at proper intervals.
The needle bar is supported vertically in bearings carried by the
vibrating arms, and has affixed to it at the rear a slotted frame, which
engages with a pin or friction pulley carried by one of the cams, whereby
motion is communicated to it. An adjustable collar is secured to the

page_text: needle bar above the shoulder of the vibrating bar, which serves to
operate the cast off bar at proper intervals by engaging with similar
collars placed thereon at suitable distances apart. These collars are all
adjustable, and secured in the desired positions by set screws.
For the purpose of strength and convenience of adjustment the needle
and cast off bars are by preference brought into close proximity, grooves
or channels in the collars being formed to admit of the same. A guide
is also afforded to the cast off bar thereby.
A socket is cast on the side of the vibrating arm, within which a
block is placed having a concave face, which is borne against the cast off
bar by a spiral spring arranged behind such block, a washer being placed
behind the spring, which receives the pressure of a set screw, which
regulates the tension of the spring, and through it the amount of friction
between the brake block and the cast off bar.
A rocking shaft is journalled in suitable bearings to the frame, and is
provided with two arms connected respectively with the vibrating arm
of the frame, and with the yoke which embraces the eccentric. The stem
end of the yoke embracing the eccentric is adjustable, its position being
regulated by means of a clamp nut and a curved slot in one of the arms.
The curvature of this slot is an arc, whose centre is at the centre of the
eccentric.
Extending downwards from the vibrating arm is a bar or shank, which
passes through a slot in the sewing plate, and extending forwards serves
to carry the vibrating shoe, which works from end to end of a slot, in
the sewing plate. This shoe is formed convex on its upper surface, and
it is provided with a vertical perforation through it at or about its centre
to receive the needle on its descent.
The thread is by preference supported to the thread guide from a
dome-shaped cage or ball holder, having at its apex an upright pivot,
which projects from the centre of a circular shoulder having a smooth
and plane surface. An opening is formed through this shoulder for the
passage of the thread at a point by preference nearer the pivot than the
periphery of the said shoulder. Upon the pivot a weighted cap rotates,
whose pressure upon the thread lying between its lower plane face and
the shoulder gives the tension to the thread, which is varied by turning
the ball holder so as to increase or decrease the extent of shoulder over
which the thread passes.

page_text: To the lower end of the cast off bar is attached by means of a set
screw an adjustable thimble, the lower portion of which is provided with
a flat face, against which is pressed by means of a clamp screw and
washer the adjustable head of the cast off. The cast off is provided with
a loop or eye, through which the needle passes, and a channelled finger,
which partially embraces the needle. The eye or loop and finger of the
cast off are connected with the flat face by means of an arm. The needle
passes down through the loop and in close contact with the cavity of the
finger. These devices are connected with the head of the cast off by
means of a short oblique shank. A perforation or opening is formed
through the middle portion of the head of the cast off, through which
the clamp screw passes, but the diameter of such perforation is larger
than the diameter of that portion of the clamp screw which passes
through it. The cast off may thus be adjusted in any direction in which
it may be desired to bring its point or finger when worn close up to the ]
needle; at the same time its eye or guide is made to bear against the
opposite side of the needle, thus securing a perfect guide. By this means
smaller needles may be used without changing the cast off..