IMPROVEMENTS IN SEWING MACHINES ESPECIALLY ADAPTED TO OR FOR THE SEWING OF STRAW BRAID
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Bristow Hunt at the Office of the
Commissioners of Patents on the 10th January 1878. A communication from
abroad by Samuel Henshall, of Philadelphia, Pennsylvania, in the United
States of America,
66
BRISTOW HUNT, of Serle Street, Lincoln's Inn, in the County of Middlesex,
Gentleman. IMPROVEMENTS IN SEWING MACHINES ESPECIALLY ADAPTED TO OR
FOR THE SEWING OF STRAW BRAID." (A. communication from abroad by Samuel
Henshall, of Philadelphia, Pennsylvania, in the United States of America.)
This Invention relates principally to certain improvements in the feeding devices
of straw-braid sewing machines, the main objects of the improvements being to
prevent the wounding or tearing of the braid, and to automatically vary the length
of the stitches during the operation of the machine.
Beneath the bed of the machine turns a driving shaft, a grooved cam on which
effects the reciprocation of the needle bar. Near one end of the machine, and
extending transversely across the same, is a shuttle race, to which is adapted a
shuttle carrier vibrated by means of a crank on the driving shaft through the
medium of a suitable connecting rod attached to a projecting arm on the shuttle
carrier. On the driving shaft is also a duplex cam wheel having one cam on its
periphery, and on its side another cam, which acts on an antifriction roller carried
by the lower end of an arm, the upper end of which is secured to a transverse
shaft to which a rocking motion is thus imparted as the duplex cam revolves.
The transverse shaft is adapted to suitable bearings on the under side of the bed,
and carries near its opposite end a vibrating arm to a slot, in which is adapted a
pin (1) on one end of a rod (2), the opposite end of which is connected to the short
arm of a lever hung to a standard and slotted at the upper end to receive a pin on
a lug projecting downward from a frame which is adapted to and arranged to slide
longitudinally on a bevilled guide plate secured to the top of the bed plate,

page_text: The radial position of the pin (1) in the slot of the said arm is governed by a
cam through the medium of an arm (3) pivotted to the said standard, and having
a projecting arm connected to the rod (2) by means of a link, the cam acting on
an antifriction roller on the end of the arm. This cam is secured to a ratchet
wheel which is operated by a spring pawl carried by the end of the transverse
shaft, so that as said shaft rocks the ratchet wheel will be moved to the extent of
one or more teeth at each rocking movement of the shaft.
The cam on the periphery of the said duplex wheel acts on the short arm of a
lever, the long arm of which bears against the lower end of a spring stem which
extends up through the bed plate and is provided at the upper end with a clamping
block.
On the lower end of the said sliding frame is a lateral projection in which is
formed a curved slot, and to guides on the upper part of the frame is adapted a
spring block having at the lower end a projecting finger which is adapted to fit into
the upper end of the slot in the projection, and thus form with the latter a pair of
jaws for clamping the material to be sewed. The spring block is acted upon by a
spring at the upper end, and is furnished at the lower end with a projecting arm,
which is acted upon by a lever controlled by a cam on the driving shaft, so that as
said shaft revolves a vertical reciprocating movement is imparted to this block.
The lateral projection of the sliding frame has also on its upper edge an adjust-
able block, and at the bottom an adjustable block, the latter having a curved arm
which extends up through the curved slot of the said projection, which is per-
forated near the top and on each side of the slot for the passage of the needle.
These blocks serve as gauges for the material to be sewed.
The needle-bar, spring block, and guide plate all have bevilled edges, and the
bearing blocks adapted to these edges. are adjustable by means of set screws so that
they may be set up to compensate for wear upon any of these parts.
The operation of the machine is as follows:- -The upper layer of braid rests on
the top of the said lateral projection or jaw, and the lower layer extends down
through the current slot therein, and is carried up through an opening in the bed
plate on one side of the needle bar. The proper overlapping of the edges of the
two layers is effected by a proper lateral adjustment of the said gauge blocks
against which the braid is pressed by the operator during the sewing operation.
When the needle is retracted the spring block is depressed so that its finger forces
à fold of the upper layer of braid down into the mouth of the said curved slot, and
into the path of the needle, which advancing carries its thread through the fold of
the upper layer of braid, and through the lower layer of the same, the thread then
being interlocked with the shuttle thread and the needle retracted. When the
needle has reached, or nearly reached the limit of its backward movement, the
spring block rises so as to release the braid, but at the same time the clamping
block descends so as to clamp said braid and hold it firmly in position longitudi-
nally. The sliding frame is now moved rearwards, and the spring block again
descends on the material, the clamp at the same time rising so that the braid is free
to be fed forward upon the next forward movement of the sliding frame which now
takes place, the above operation being repeated.
The above feeding operation is direct and positive, and yet has no tendency to
wound or injure the braid, or strain one layer more than the other, while the labor
of the attendant is confined simply to pressing the edges of the layers against the
gauge blocks or plates.
When the machine first commences to operate upon the tip of a hat, the roller on
the end of the arm (3) occupies a position near the base of the cam it governs, and
the pin (1) on the rod (2) consequently occupies a position near the inner end of
the slot in the said vibrating arm, so that the throw of the arm and the extent of
the reciprocation of the sliding frame is slight, and the stitches made by the machine
are thus comparatively short. As this cam turns however the pin (1) is moved

page_text: further and further from the inner end of the slotted vibrating arm and the extent
of movement of the sliding frame, and consequently the length of the stitches is
gradually increased until they reach their maximum length.
When a hat is finished the parts are restored to their former positions, so as
to produce short stitches when the machine commences to work upon a new hat.