Improvements in and relating to Sewing Machines.
Year: 1889

page_text: Date of Application, 14th Oct., 1889
Complete Specification Left, 13th Aug., 1890-Accepted, 13th Sept., 1890
PROVISIONAL SPECIFICATION.
Improvements in and relating to Sewing Machines.
We, JOHN MCKENZIE, Cabinet Maker, of 5 Eglinton Lane, and ROBERT STEWART,
Builder, of 50 Tullie Street, both in Glasgow, Lanarkshire, do hereby declare the
nature of our invention to be as follows:-
This invention has for its object to ensure the automatic stopping of sewing
machines driven through a crank or crank shaft, at the upper centre, or a little beyond
the upper centre, when no longer actuated by the pressing down of the treadle, and
which improvements will also turn the crank and raise its connections during the
upward motion of these, and make such machines much easier and more comfortable
to drive than has been the case heretofore, and dispense with the necessity of the
operators pushing down the back arm of the treadle with their heels, which is an
awkward motion to most people.
The nature and novelty of the improvements consist in the fitting and use of
re-acting spiral, india rubber, or equivalent drawing spring, either connected to the
treadle or connecting rod or other part of its reciprocating connections, and to a fixed
or stationary point on the machine, or it might be to the floor or basement, or by an
eye to the crank shaft itself, or otherwise such a spring might be connected to some
point in the treadle or connecting rod, and to a shorter crank at right angles to the
driving crank, which spring in any of these cases would be mounted so as to be. put
in tension by the downward action of the forepart of the foot and the oscillating
treadle or connecting rod, and so re-act to pull these parts up, on the foot being raised
off the treadle, and drive the crank shaft on the upward stroke and half of its revolu-
tion, and the fixed points of the spring be so set also as to bring the crank and crank
end of the connecting rod a little past the line of its upper dead centre as its stopping
point, always ready for starting. Although a drawing spring has been mentioned as
preferred, as being lighter and more suitable for giving a greater motion and being
connected to the connecting rod or the outer ends of the treadle, yet still it will be
obvious that stronger pressing blade or spiral springs might be used acting on the
treadle near its fulcrum, or strong drawing springs might be used with little motion
acting under the back arm or heel part of the treadle.
Dated the 12th October 1889
W. R. M. THOMSON & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in and relating to Sewing Machines.
We, JOHN MCKENZIE, Cabinet Maker, of 5 Eglinton Lane, and ROBERT STEWART,
Builder, of 50 Tullie Street, both in Glasgow, Lanarkshire, do hereby declare the
nature of our invention, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement in writing,
reference being had to the accompanying sheet of drawings, and to the letters and
figures marked thereon, that is to say:-
Our invention has for its object to ensure the automatic stopping of sewing
machines driven through a crank or crank shaft, at the upper centre, or a little beyond
the upper dead centre when ceased to be actuated by the pressing down of the foot
treadle, or it might be beyond the lower dead centre when pressed up by the treadle,
and which improvements will also turn the crank and raise its connections during the
upward motion of these from the lower dead centre, all by the action of a spring or
springs as hereinafter described; and which will make such machines much easier and
n.. 11

page_text: more comfortably driven than has been the case heretofore, whether the flywheel has
been counter-balanced or not for the weight of the treadle, connecting rod and crank
and may dispense with the necessity of the operators pushing down the back arm of
the treadle with their heels, which is an awkward motion to most people.
And in order that our said invention and the manner of performing or carrying the
same into effect or practice may be properly understood, we have hereunto appended
an explanatory sheet of drawings illustrating a few modes of applying our improve-
ments, in which the same reference letters are used to indicate corresponding parts in
all the figures where shown. Figure 1 is a sectional end elevation and Figure 2 a
front side elevation of one construction of a sewing machine frame and driving
mechanism or gearing driven by a crank B connecting rod C and foot treadle D
shewing the new or improved application of our spring thereto in different ways for
effecting the purposes of our invention.
Referring to these figures :-A, A, are the two side standards or frames bound
together at top and bottom A', A", by the central frame A2 at right angles, and by
the top or table part A. This machine is shown as driven by a crank shaft B B
carried in journal bearings at B B in the right hand side of the frames A, A² with
band driving flywheel B2 for directly driving the sewing machine, actuated by the
connecting rod Cand the foot treadle D, which is carried in fulcrumed bearings at Du
at the lower part of the frame A2, the arrows on the fly-wheel B2 showing the direction
of motion. The upper working end C₁ of the connecting rod C is jointed to the
crank B, or it might be a crank pin in the driving Hywheel B2 when that is mounted
to rotate on a stud centre as it is in some machines, instead of on the crank shaft B¹.
The lower end C of the connecting rod C is jointed on a pin D' in the upper arm of
the treadle D, all so far much in the usual manner for driving sewing machines by the
foot.
The nature and novelty of our improvements consist in the fitting and use of an
acting or re-acting spiral, india rubber, or other equivalent drawing spring or springs a
connected by its one end a¹ to the treadle D at D³, or to a pin C3 in the connecting
rod C, and at its other end a" to a fixed or stationary point at A³ on the centre
frame A2 or one of the side frames A of the machine, both of these arrangements
being indicated in Figures 1 and 2 although only one is required on the machine.
The spring a in these cases is put in tension by the downward action of the fore part
of the foot and the oscillating treadle D or connecting rod U, as indicated in dotted
lines at d, d¹, d¹¹, d², in Figure 1, and so re-act to pull these parts up from their lowest
dead centre ', of the crank pin B on the foot being raised off the treadle D, and
drive the crank or crank pin B of the crank shaft B on the upward stroke and half
of its revolution; and the fixed points a¹ of the spring a are so set also as to bring
the crank or crank pin B and crank end C' of the connecting rod C a little past
the line of its upper dead centre b as its stopping point, always ready for starting.
Figure 3 shows a sectional end elevation of a sewing machine corresponding to
Figure 1, but showing the spring a attached to other parts of the moving mechanism
in accordance with and for the same purposes and advantages of the invention. By
one arrangement in this figure, the spiral or drawing spring a is shown as having its
one end a attached to a pin C³ in the connecting rod C, but it might be down to the
treadle D or to a fixed point in the floor or basement near the same line, and having
its other or upper end a" attached to a shorter crank b' at or nearly at right angles to
the driving crank B, which might be screwed on to the crank pin B when overhung,
and always bring the crank pin B and its connecting rod C and treadle D to their
normal stopping position shown in the drawings, that is, to the position of the angled
dotted line d d for pressing down the treadle and starting the driving flywheel in the
direction indicated by the arrows on it. Or instead of using the spring a connected
in this way it might be connected at one end a¹ to an eye on the main crank or crank
pin B, of the crank shaft B' itself, or to the upper end eye C¹ of the connecting rod C,
and have its other end a¹¹ connected to a fixed stud or point A in one of the frames A,
as dotted in at all in Figure 3. These springs a may be attached at one end to other
reciprocating or moving parts of the mechanism and at their other ends to fixed points

page_text: on the frame A, or the floor or basement, than that shown and described, to bring the
crank B, and its connecting rod C to stop in a mean starting angle or position in
advance of either of the dead centres 6 or b¹ by the downward or upward motion
respectively of the treadle D as described. Although a drawing spring a has been
shown and described as preferred, as being lighter and more suitable for giving a
greater motion and being connected to the connecting rod C or the outer ends of the
treadle D, which have the greatest motion, yet still it will be obvious that a strong
blade spring a might be fitted under the treadle D near its fulcrum as shown in sharp
and dotted lines in Figure 1, to bring the treadle D and its connecting rod C and
crank B to their said normal starting position in advance of the dead centres b, ¿¹; or
strong spiral pressing or drawing springs a³ might be used with little motion acting
under the treadle D on either or both sides of the fulcrum D as indicated in Figure 3
or a double blade spring a might be secured on the lower end of the connecting rod C
to act on stops on the treadle, indicated at d in Figure 3, to bring the connecting
rod and treadle D to their normal starting position with the crank B, off their dead
centres b, b, as indicated in Figures 1 and 3. It will be understood that the crank or
crank pin B might also be stopped in a similar manner at an angle of 45 degrees or
so, in advance of the lower dead centre 61, as indicated in dotted lines at B* in
Figure 3, for starting the driving wheel B2 in the upward forward direction by the
raising of the connecting rod and downward pressure of the back arm D2 of the
treadle D, and in that case the springs would have to act at an angle to bring
the crank B or the top of the connecting rod C to the position Bx, and the treadle to
the position d, d³, as indicated by the dotted spring as in Figure 3, attached to some
fixed point A projecting from the frame A, or from another crank as b² at right
angles to the crank Bx down to the lower part of the connecting rod C.
It will be understood that the said new springs a to as may be made strong enough
to balance the weight of the connecting rod C and treadle D as well as bring the
crank B to the stopping and starting position in advance of the dead centres b, b',
but very light springs will only be necessary when these parts are balanced by a
counterweight on the flywheel B².
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
.
First. In sewing machines, the herein described modes and means of applying
springs to the treadle, crank, connecting rod or other reciprocating or moving part of
the machine, substantially as and for the purposes set forth in reference to and shown
in the accompanying drawings.
Second. In sewing machines, the fitting and use of a spiral, india-rubber, blade, or
equivalent spring or springs attached to and acting in combination with the treadle,
crank, connecting rod or other reciprocating or moving part of the machine, so as to
bring the crank and crank end of the connecting rod to an angle in advance of the
line of their dead centres in a good stopping or starting position for the downward or
upward motion of the treadle, substantially as and in the manner and for the purposes
herein described, in reference to and by way of application shown in the accompanying
drawings.
T
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.