IMPROVEMENTS IN SEWING MACHINERY
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Frank Armstrong at the Office of
the Commissioners of Patents, with his Petition, on the 8th December
1866.
I, FRANK ARMSTRONG, of Waterbury, Connecticut, United States of
America, now of No. 8, Southampton Buildings, Chancery Lane, in the
County of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SEWING MACHINERY," to be as follows:-
The said Invention relates to an adjustable device designed as an attachment
to the so-called "Wheeler and Wilson" sewing machine, for which Letters
Patent were granted to Auguste Edouard Loradoux Bellford, bearing date the
Sixth day of October, A.D. 1852, No, 251, which device being secured upon
the said machine will operate in combination therewith to produce the
well-known "Grover and Baker" or double loop stitch, and also a three-thread
stitch. Devices for this purpose have already been introduced, but these are
so constructed that their proper adjustment is exceedingly difficult to accom-
plish, and they require constant attention on the part of the operator to insure
the work being properly performed. Neither of these devices, as hitherto
constructed can be used with the ordinary cloth plate of the "Wheeler and
Wilson" machine, the arrangement of parts in each of the said devices
requiring a peculiar modification in the form of the said plate. These devices

page_text: also (except in one arrangement where the cloth plate is permanently secured
to the attachment) have each to be provided with a separate ring slide which
greatly increases the cost of their construction, while the necessity of removing
the ring slide of the machine and substituting in its place the ring slide of the
attachment (which has to be done every time the latter is used) materially
increases the difficulty of adjusting the same. The mode of securing the
attachment by means of the thumbscrew employed to secure the ring slide of
the machine in its place is. also very objectionable, as the said thumbscrew
requires making very tight, and to do this properly is generally beyond the
strength of a female operator. The arrangement of the support for the under
thread spool in the above-mentioned devices leaves the under thread constantly
liable to have its tension deranged by the dropping of the cloth thereon which
is a source of great trouble to the operator, and often causes the work to be
imperfectly executed.
My improvements relate chiefly to the novel construction and arrangement
of parts of the attachment whereby it can be readily and accurately adjusted
and secured upon a "Wheeler and Wilson" machine without requiring the
removal or adjustment of the ordinary ring slide, cloth plate, or other parts of
the said machine, and also to the peculiar arrangement of an adjustable
support for the under thread spool in combination with the under thread
carrier and guide, whereby the proper tension of the under thread is preserved
during the working of the machine, and the said spool can be more readily
removed and changed when desired.
: The working parts of my improved attachment are supported on a frame of
cast iron or other suitable metal. The said frame is constructed with a slot
or aperture which is made open at the inner edge of the said frame to allow
it to pass under the head of a holding-down bolt which secures the attach-
ment in its place, and which passes through the bed plate of the machine and
the table or bench upon which the latter is supported; this slot allows the
frame of the attachment to be drawn from under the head of the holding-down
bolt when the nut thereof is slightly slackened, and also greatly facilitates
the adjustment of the said attachment when the same is replaced upon the
machine; a portion of the said frame is formed to pass easily between the
two standards which support the cloth plate in a "Wheeler. and Wilson
machine; this portion of the frame has a certain amount of play between the
said standards, and the same amount of play is allowed for the holding-down
bolt between the sides of the slot in the said frame. Two small adjustable
slotted plates are fitted upon this portion of the frame, and are secured to the
"

page_text: said frame by screws 'which pass through their slots; these plates are so
arranged that their ends can be made to bear against the sides of the standards
which allows the accurate adjustment of the attachment upon the machine to
be effected with great facility. When this adjustment has been once properly
effected the attachment can be removed and replaced as often. as desired
without further trouble.
The under thread carrier is so formed that its point is higher than the top
of its spindle; this construction of the said carrier allows the ordinary cloth
plate of the "Wheeler and Wilson machine (which has turned down edges) to
be employed with the attachment. The spindle of the said under thread carrier
is supported to work in suitable bearings formed in the frame, and is provided
with a projection or finger for the lever of the attachment to act upon; this
spindle is also provided with a spiral spring arranged to act in the opposite
direction to this lever; the said lever is fixed upon an upright pin or axis
fitted to turn in bearings formed in the frame. The same pin or axis also
carries a short arm which by means of a set screw is adjusted and secured
in any required position upon the said pin or axis; the end of this arm-is
provided with a flat web for the feed cam on the mandril of the machine to
act upon, and by adjusting the said arm upon its pin or axis the movement of
the under thread carrier is regulated.
The under thread tension device consists of two discs or plates, between
which the thread is passed; one of the said discs being fast and the other
loose on an upright stud secured on the attachment frame. The loose disc is
forced up against the fixed disc by a spring, whose pressure is regulated by a
nut fitted on the bottom of the stud.
The spindle of the under thread spool is supported upon the extremity of
an adjustable tongue of metal which is secured by a screw upon the end of the
attachment frame farthest from the under thread carrier; the said screw forms
a pivot or centre for the said tongue to turn upon. When the attachment is
secured upon the machine this tongue is so adjusted that the spool is under
the front edge of the cloth plate. The under thread is led from the said spool
through the tension device and through the eye of a guide, which is secured
upon the attachment frame near the under thread carrier; the said guide is
so arranged that its eye is a little below the front of the under thread carrier,
and the thread passes from this eye to the said carrier. When the under
spool is empty it is brought from under the cloth plate by turning the
adjustable tongue upon its pivot, and can then be easily removed from its
spindle without disturbing the said cloth plate.

page_text: When the attachment is properly secured upon a "Wheeler and Wilson"
machine, and it is desired to produce the double loop stitch the upper or
needle thread only of the said machine is used with the under thread of the
said attachment, but by the employment of the under bobbin thread of the
said machine a three-thread stitch may be formed.