IMPROVEMENTS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Marshall Henry Pearson at the
Office of the Commissioners of Patents on the 18th January 1882.
MARSHALL HENRY PEARSON of Leeds in the County of York
IN SEWING MACHINES
"3
"IMPROVEMENTS
Firstly. In my improvements I use the ordinary straight needle the needle bar
for which is fitted in a slide which is hinged or pivotted at its upper end. To this
is given an intermittent radial reciprocating motion by a cam on the driving shaft
and the required vertical movement is imparted to the needle bar through a heart
cam attached to the slide by a crank or cam arrangement on the driving shaft.
The radial movement is imparted to the slide when the needle, has passed
through its work and at rest; this radial movement imparts a lateral movement
to the needle and feeds the material forward but prior to imparting this lateral
movement to the material I cause the needle to rise slightly for the purpose of
relieving the leather from the throat piece I also cause the pressér foot to rise a
little for the purpose of allowing the leather to be relieved as above stated, but it
is afterwards brought down again onto the leather with a firm pressure and locked
there. The object of the locking being to prevent the friction of the needle lifting
the presser foot. The locking arrangement is effected through a lever and spring
and relieved by an intermittent tappit arrangement. The lifting movement for
the presser foot has also a locking motion applied thereto, this is actuated by a.
tappit cam through a toggle arrangement. The above named locking is effected in
a similar manner to that described in the Specification of the Letters Patent
granted to me the 28th January 1879 No 348.
I employ a circular shuttle which is of the same construction as that described
in the Specification of the Letters Patent granted to me the 12th August 1880
N° 3294 this is mounted in a box on the end of a short hollow spindle. A rotary,
reciprocating motion is imparted thereto and for this purpose I provide an internal
screw within the hollow short spindle and within the interior of the spindle is
provided a piston having a stud thereon fitted so as to slide freely within the .
internal screw. To the piston is imparted a reciprocating motion by means of a
cam on the driving shaft through a suitable connecting rod imparting thereby
through the stud and internal screw the required rotary reciprocating motion to
the shuttle.
The motion to the thread lever is imparted by a bell cam on the driving shaft
this operates in conjunction with a thread locking device mounted on the needle
slide carrier. The thread continues to be locked during the whole of the upward
movement of the thread lever. I couple to the thread lever a tube by preference
of brass or copper this is mounted at its end in a frictional bearing through this
tube which is heated by any convenient means is passed the thread already

page_text: saturated with wax for the purpose of keeping it soft. The upward movement of
the tube is imparted by the thread lever to which it is attached for the purpose of
providing thread for the varying thicknesses of material or length of stitch. The
tube is drawn downwards by the thread the distance depending upon the amount
thereof required. This movement may in some cases be reversed.
I also provide another heated tube which is secured to the front of the needle
bar carrier through which the thread passes on its way to the needle after having
left the thread lever.
The shuttle box end is also heated.
This machine may also be employed with unwaxed threads-when such is the
case the above mentioned tubes and shuttle box end need not be heated.
Secondly. In combination with the use of the hereinbefore mentioned circular
shuttle I employ for some purposes an awl which pierces the hole for the needle
this may either be mounted on the needle bar and side by side with the needle
fitted so that their distance apart can be adjusted to suit the length of stitch; or
the needle and awl may be mounted on separate slides. In this arrangement the
awl pierces the hole and feeds the material leaving the hole clear for the needle
with its thread to pass through. The lateral and vertical movement for the needle
and awl are produced by suitable levers and cams of ordinary construction.
Thirdly. I apply also a curved awl in combination with the curved eye pointed
needle employed in machine for which Letters Patent were granted to me dated
12th August 1880 N° 3294. This may be either on the same lever as the needle
having an arrangement whereby their distance apart may be regulated or when
preferred they may be mounted on separate levers. The required radial and
lateral movements being imparted thereto from suitable cams or their equivalents.
By the above arrangements finer needles may be employed than when the needle.
alone is used for piercing the material.
Fourthly. My improvements consist in the construction of shuttles such as are
used on the "Thomas" and other machines whereby such machines may be worked
with a waxed thread.
The cross section of shuttle used in these machines is D shaped, which form
presents such a large surface to the thread that when waxed so great is the friction
the shuttle cannot force its way through the loop without breaking or other
damage to the thread. To avoid this I construct the shuttle with a cross section
of a rectangular form having projecting ribs at its angles. By this form the
thread is in contact with the shuttle at two points only thereby reducing the
friction to such an extent that waxed threads may be used.
Fifthly. In my further improvements I dispense with the "eye pointed" needle
and substitute instead thereof an awl for the purpose of piercing the material, and
below the work I employ a hooked needle. The awl having passed through the
material to form the hole returns and is followed by the hooked needle which
passes through the material and projects above the surface thereof. When in this
position the top thread is laid into the hook by a looper thus having sufficient
movement to give off enough slack thread on each side to supply it in its descent
without any movement of the thread on the hook.
;
After the needle has passed to the bottom of its stroke, the shuttle (which may
be of the above described rectangular form or a horizontally reciprocating circular
shuttle) passes between the threads and locks the stitch which is afterwards.
tightened in the ordinary way.
=
In this arrangement the material may be fed forward either by the lateral
movement of the awl or hooked needle.