SEWING MACHINES."
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by 1
Henry Pearson at the
Office of the Commissioners of Patents on the 18th October 1881.
MARSHALL HENRY PEARSON, of Leeds, in the County of York.
IN SEWING MACHINES."
"IMPROVEMENTS
In my improvements I use the ordinary straight needle, the needle bar for which
is fitted in a slide 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 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 is at rest; this radial movement imparts a lateral movement to the
needle and feeds the material forward, but prior to imparting this lateral move-
ment 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 presser 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 from
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 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 Letters Patent granted to me the 12th August 1880,
No. 3294; this is mounted in a box on the end of a short hollow spindle. A
rotary reciprocating movement 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
Di 071

page_text: 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 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.
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.