IMPROVEMENTS IN SEWING MACHINES
Year: 1858

page_text: PROVISIONAL SPECIFICATION left by Alexander Mackenzie at the Office
of the Commissioners of Patents, with his Petition, on the 16th
December 1858.
I, ALEXANDER MACKENZIE, of Glasgow, in the County of Lanark, North
Britain, Mechanist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SEWING MACHINES," to be as follows, that is to say:-
This Invention relates to various improvements in the mechanical arrange-
ments of machinery or apparatus for sewing and stitching, whereby such
machinery is rendered more effective in its actual work, and more durable in
its wearing details, combined with superior simplicity of parts; than has hitherto
been the case.
According to one portion of the Invention; the improvements refer to what
is'known as the "circular needle" machine, the sewing or stitching action
being effected by the combined action of a straight needle of vertical action,
and a curved needle of horizontal action. The framing of the machinery is
generally similar to that already in use, consisting of a rectangular table
frame open beneath, and formed with a platform top for the working
operations. The machine is actuated by a treadle or other convenient move-
ment, which works the first motion spur wheel running loose on a stud in the
framing. This wheel gears beneath with a spur pinion on the end of a
horizontal shaft beneath the platform, and which shaft carries a grooved disc
cam working a stud pin on a short horizontal segmental rack lever arm,
•

page_text: working loosely on an end stud on the lower face of the platform. The free
end of this rack lever is formed with a segmental toothed rack gearing with a
horizontal pinion, the vertical stud of which carries the curved or circular
needle situated immediately beneath the level of the platform, in which there
is a suitable aperture for access to the needle. Thus, the continuous rotation
of the first motion shaft gives a horizontal vibratory motion to the rack lever,
and a corresponding reciprocatory partial rotatory motion to the needle. The
first shaft also derives the feed motion for the periodical traverse of the fabric
being sewn, and it carries a second and duplex cam for this purpose. This
cam rotates beneath a horizontal feed motion bar, capable of both a longi-
tudinal and lateral movement, a spring being fitted at one end for the
former, and another above it for the latter movement. From the central
portion of this feed bar there projects up through an aperture in the platform
a vertical arm with a roughened or serrated top piece, over which the fabric
is passed during working. The under side of the feed bar is formed with a
deep shoulder for the cam to work against, and the result is, that at each
revolution of the cam the roughened feed surface or plate is alternately lifted
up and down, and pushed back and forward, the springs affording the return
movements. One end of the bar bears against the periphery of a small
adjustable eccentric or cam piece, set on a stud in the frame, and capable of
being set round at pleasure by a hand lever with a setting screw stud pro-
jecting through the frame, and capable of traverse along a segmental slot. In
this way the operator can set the eccentric round to any required position, and
so regulate the traverse of the feed bar. The actual roughened feed piece
may either be solid or in vertical divisions. If formed in divisions, their lower
ends work in suitable guides on the feed bar against bottom springs, so that
when folds, edges, or irregular thicknesses of fabric are being operated upon,
each roughened piece comes to a fair bearing, and secures the fabric properly
for an even straight forward traverse. The first motion spur wheel also gears
with an upper pinion on an upper horizontal shaft working through the upper
frame bracket arm. The front end of this shaft carries a differentially face
grooved cam operating upon the stud of the vertical needle bar, the differential
curvature being such as to give the required up-and-down movements and
rests of the vertical needle in its action in conjunction with the curved needle
beneath. The track of the curvature of action of the cam is formed with very
easy changing bends, so that the action between the stud and the bends is
smooth, working without shocks or jars, and avoiding unreasonable wear of
the parts. The cam is also so contrived, that it operates upon or with its
easiest leverage at the instant when the greatest resistance is opposed to the

page_text: passage of the needle through the material being sewn. The upper spring
presser or resisting surface for the roughened feed piece is carried and operates
in the usual way, and its face may or may not be in divisions or sections to
correspond with those of the roughened feeder. The needles are attached to
their carrying bars in such a manner as to be easily adjustable and securely
held in accurate position for work. Each needle is formed with a broad flat
socket piece, formed to fit accurately in a recess in the face of the needle bar,
and so as to be flush with the latter; over this recess there is hinged a
binding clasping bar, the free end of which is capable of being set hard down
by a pinching screw. In this way the needles may be changed with the
utmost facility, whilst they must necessarily be set with perfect accuracy. For
curvilinear or differential line sewing, provision is made for traversing, the
fabric being sewn so as to follow any predetermined line. For this purpose a
disc wheel cut or formed on its periphery in accordance with the intended line
of sewing to be produced in the manner of the surfaces employed in the
turner's "rose engine," is fitted up in the gearing of the machinery so as to
bear during its revolution upon the movements in connection with the feeder.
This may be accomplished in various ways, but it is preferred to cause the
operating disc to bear against a lever arm working on an end centre carrying
a bevil pinion, which pinion is in gear with a segmental toothed rack on a
short horizontal arm, which works round the needle bar as a centre. The
needle bar has at its upper end a horizontal ring piece, into the interior of
which there projects the lower end of an adjustable incline piece carried by
the top of a vertical lever set on a horizontal stud centre, capable of traversing
in a vertical slot. The bottom end of this lever carries the roughened
traversing feed pieces, which in this instance operates from above. The same
arm which works upon the needle bars as a centre is also connected by means
of a slot with the upper part of the vertical feed lever, so that whatever
motion is imparted by the guide disc wheel to the gearing of the short arm
before referred to, is communicated as regards lateral or transverse action to the
feed lever, which is at the same time being operated upon for the forward
traverse of the feed surface by the ring on the needle bar acting against the
incline piece on the top of the feed bar. In this way the traversing feed has
a compound motion transmitted to it, a forward traverse from the needle bar
movement, and a lateral or differential traverse from the disc wheel movement,
and thus the stitching may be carried on to suit almost any desired figure for
ornamental or other work. All or most of these improvements may be
employed in various classes of sewing machines.
In what are known as "shuttle" machines, the sewing thread is wound for

page_text: use in the "cop" form, instead of. being wound up as a bobbin, .With this
arrangement the thread comes directly and evenly off in sewing, without thie
tendency to "snarl" or coil up, and get loose, always felt in the use of
bobbins. :
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