An Improvement applicable to "Chain-stitch" Sewing Machines.
Year: 1899

page_text: Date of Application, 29th Nov., 1899
Complete Specification Left, 29th- Aug., 1900-Accepted, 29th Nov., 1900
PROVISIONAL SPECIFICATION.
An Improvement applicable to "Chain-stitch" Sewing Machines.
I, ALFRED BIRCH, of Alpha Machine Works, Worcester Street, Higher
Broughton, Manchester, in the County of Lancaster, Engineer, do hereby declare
the nature of this invention to be as follows:-
This invention relates to what are known as "chain-stitch" sewing machines
and the object of the invention is to ensure the formation of a positive loop
by means of an improved looper which does not revolve but slides or oscillates
to-and-fro in a straight or curved path.
The point of this improved looper I make of flat metal sufficiently thin to
pass between the needle and the thread with little or no resistance.
The flat side of the point is parallel to the needle. At a suitable distance
(say about a quarter of an inch) from the said point a small ear or catch is formed
on the back so as to bend away from the needle, and immediately beyond this
point a dip, crank or flap is formed in the looper, into which the needle dips,
the said gap being made sufficiently wide and deep to clear the needle. The
looper is then bent upwards on the other side of the gap to a centre common with
that of the blade or point and it then takes the form of a short horizontal axle
or spindle which is supported so as to be able to rock to-and-fro in a suitable
bearing.
As the flat point or blade of the looper is approaching and entering between
the needle and the thread, the flat point remains parallel to the needle but
directly the gap or crank comes opposite to the needle the looper is caused to
twist or swivel on its axle for about a quarter of a turn so as to open out the
loop of the thread to allow the needle to pass through.
This sideways turning or swivelling of the looper at the proper moment
may be caused by means of a cam acting either directly or indirectly or by any
other suitable mechanical means.
1000
COMPLETE SPECIFICATION.
An Improvement applicable to "Chain-stitch" Sewing Machines.
ALFRED BIRCH, of Alpha Machine Works, Worcester Street, Higher Broughton,
Manchester, County of Lancaster, etc., do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:―
"
This invention relates to what are known as chain-stitch" sewing machines
1
ALFRED BIRCH, of Alpha Machine Works, Worcester Street, Higher Broughton,
Manchester, County of Lancaster, etc., do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:―
This invention relates to what are known as 'chain-stitch" sewing machines

page_text: and the object of the invention is to ensure the formation of a positive loop by
means of an improved looper which does not revolve but slides or oscillates to-
and-fro in a straight or curved path. The bill or point of this improved looper
I make of flat metal sufficiently thin to pass between the needle and the thread
with little or no resistance. The flat side of the bill or point is parallel to the
needle. At a suitable distance (say about a quarter of an inch) from the bill-
point, an ear, catch or stop is formed on the back so as to bend away from the
needle, and immediately beyond this point a gap and flap is formed in the
looper, into which the needle dips, the said gap being made sufficiently wide
and deep to clear the needle. The looper is then bent upwards on the other side
of the gap to a centre common to that of the blade or point and it then takes
the form of a short horizontal axle or spindle which is supported as to be able
to rock or swivel to-and-fro in a suitable bearing. As the bill or blade approaches
and passes between the needle and the thread, the flat remains parallel to the
needle, but directly the gap comes opposite to the needle, the looper is caused
to twist or swivel on its axle for about a quarter of a turn or revolution so as
to open out the loop of the thread for the needle to pass through.
The accompanying drawings illustrate one of obviously. various methods
of effecting the necessary oscillatory and swivelling movements.
In Figure I the flap of the looper A is swivelled or twisted to an horizontal
position by the tappet B tapping or depressing the lever C which communicates
with the looper by the connecting link D. Whilst the looper is in this position
the thread is opened out and the needle passes between and decends through
the gap in the flap. As the tappet revolves, the lever C ascends and permits
the spring E to bring the flap or looper to a vertical position (i.e. parallel to
the needle) as shewn in Figure 3, in which position it backs past the needle
directly the larger throw of the tappet B allows the spring F to operate. The
end view Figure 2 shews the relative positions of link & spring.
quadrant G G oscillates upon the stud H. The tappet B is held in a driven
shaft-end. The ear or catch beforementioned is shewn at T in Figure I and
by the dotted line in Figure 3.
The
Having now particularly described & ascertained the nature of my said in-
vention & in what manner the same is to be performed, I declare that what
I claim is:
A thin flat bill provided with a gap to receive the needle and an ear or equiv-
alent to carry the thread along to prevent it falling into the gap, the said
bill twisting in the same centre line as its carrying stem or axle.
Dated this 28th day of August 1900.
ALFRED BIRCH.