Improvements in Overhead Sewing-machines.
Year: 1895

page_text: Date of Application, 2rd May, 1895-Accepted, 8th June, 1895
COMPLETE SPECIFICATION.
Improvements in Overhead Sewing-machines.
'
I, WILLIAM WEBSTER, of Germani: Works, Armley, Leeds, in the County of
York, Engineer, do hereby declare th nature of this invention and in what manner
the same is to be performed to be particularly describe and ascertained in anl
by the following statement:-
This invention relates to overhead sewing-machines of the Laing type and
comprises, inter alia, improvements in the means for driving the needle.
And in order that my invention may be clearly understood I will proceed to
describe the same with the aid of the accompanying drawings, in which
Fig. 1 is a longitudinal sectional elevation of a Laing overhead sewing-machine
provided with my improvements;
Fig. 2 is an end elevation of the same, and
Fig. 3 is a sectional plan thereof.
Fig. 4 shews to a larger scale one of the conical frusta used for driving the
needle.
In this machine, the needle a, which has about 2 convolutions, is driven by means
of three conical frusta provided with screw-threads (see Fig. 4) with which
the needle a engages.
The needle a has a left-handed (anti-clockwise) twist and
the threads b' of the frusta b a right-handed (clockwise) twist. The frusta or
needle-drivers are secured respectively to and driven by means of bevel-
wheels c', and c³, which are connected together by two bevel-wheels d.
bevel-wheel is keyed on a shaft e', whilst the wheels c² and are free to rotate
on studs and respectively. On the shaft is keyed a bevel-wheel which
gears into a like bevel-wheel g on the main shaft h of the machine.
The
In order to facilitate the adjustment of the needle-drivers to the needle a, for
the purpose of adjusting the friction on the needle, the said needle-drivers 5 are
mounted loosely on bosses i of the wheels c',, and cand are tightened up against
the said wheels by means of nutsj screwed upon the projecting euds of the bosses i.
The nuts are made with right-handed threads, so that they will be always
tightened or kept tight against the drivers by the tendency of the latter when
rubbing against them to cause them to turn on the screw threads on the bosses of
the wheels c', c², and c³.
In order to prevent the needle from working out of engagement with the screw-
threads of the drivers b. 1 form each of the said screw-threads by cutting a
channel of suitable depth and shape in each of the conical drivers and cause this
channel to terminate in a stop / (Fig. 4).
The thread-cylinder which has a taper, or conical shaped end with a screw-
thread formed thereon, as described in the Specification of Letters Patent
previously granted to me, No. 24893 of 1893, has its end-ways movement
controlled by means of a collar m, which is located on the cylinder shaft a and is
pressed down against this shaft by a coiled spring o, which acts between a plute p
secured to the work-table y and a winged or thumb nut on a rod 8, which is
st cured to the collar and passes through the spring o and the plate p. As will
le evident, the friction of the collar on the shaft can be regulated as desired by
means of the nut r.
For the purpose of varying the speed of the machine, as is often necessary when
changing from a heavy to a light material, or rice rersú I provide a set of stepped

page_text: t
pulleys on the main-shaft and a corresponding set of stepped-pulleys on the
counter-shaft u; or I may employ a pair of reversely arranged speed cones in lieu
of t t for the same purpose.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. In an overhead sewing-machine, mounting the conical needle-drivers b on the
bosses of their actuating toothed wheels and securing them in position on the said
wheels by means of nuts on the said bosses, substantially as herein described.
2. In an overhead sewing-machine of the kind herein referred to, providing each
conical needle-driver b with a screw-thread b', terminating in a shoulder & substan-
tially as described and shown for the purpose specified.
3. For regulating the end-ways movement of the thread cylinder of an overhead
sewing-machine of the kind herein referred to, the combination with the cylinder
shaft n, of the collar m fitted loosely upon it and provided with a rod s that extends
through a plate p secured to the work-plate of the machine and is fitted with a nutr
and a coiled spring o encircling the rod and arranged between the said plate p and
nut as described and shown.
4. The improved overhead sewing-machine, constructed, arranged and operating
substantially as herein before described with reference to and shewn in the accom-
panying drawings.
Dated this zou day or may 1000.
R. E. P. CRAVEN,
Registered Patent Agent,
22, Victoria Chambers, South Parade, Leeds, Agent for the Applicant.