Improved Lifting Jack.
Year: 1892

page_text: Date of Application, 12th Mar., 1892
Complete Specification Left, 17th Oct., 1892-Accepted, 19th Nov., 1892
PROVISIONAL SPECIFICATION.
[Communicated from abroad by the firm of HERREN BIELEFELDER WINDEN
AND WERKZENGMASCHINENFABRIK HUCK & Co., of Herford Strasse,
Bielefel, Germany.]
Improved Lifting Jack.
I OLIVER IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention to be as follows:-
This invention relates to an improved construction of lifting jack which I will
describe with reference to the accompanying drawings, in which Figures 1 and 2
shew two vertical sections at right angles to each other. On the shaft that is
rotated by the crank handle is formed a pinion e that gears with a spur wheel d
whose shaft is formed with two pinions c c, one on each side of d, that gear
with two spur wheels bb on the shaft h. Between these wheels the shaft carries a
pinion a that gears with the toothed lifting rack i. The wheels bbas also the
pinions c, e, are so set relatively to each other that the teeth of the one wheel and
pinion are shifted somewhat round relatively to those of the other wheel and pinion,
so that a practically uniform effort of rotation is obtained and all dead points are
avoided. The pinion e and wheel & might of course be replaced by a worm and
worm wheel.
By means of the above described construction of the driving gear there will be
obtained, in addition to a quiet working, a perfectly reliable action of the jack;
the stability will be increased and the wear of the gear considerably diminished in
consequence of the uniform distribution of the pressure.
At the same time, the construction affords the advantage as compared with the
ordinary construction of jacks in which two pinions act simultaneously on the rack,
that the first tooth space of the rack can be situated a greater distance from the
claw j, which is of importance, as in lifting the load the rack bar is subject to
compression at the claw, while at the teeth it is subject to a bending strain, and
consequently a breakage of the rack bar will be more readily prevented, the greater
is the distance between the top tooth space and the claw.
With this construction also, the length of the jack can be reduced without
reducing the extent of lift.
Dated this 12th day of March 1892.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Lifting Jack.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, 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 an improved construction of lifting jack which I will
describe with reference to the drawings accompanying my Provisional Specification,
in which Figures 1 and 2 shew two vertical sections at right angles to each other.
On the shaft that is rotated by the crank handle is formed a pinion e that gears
with a spur wheel d whose shaft g is formed with two pinions cc, one on each side
of d, that gear with two spur wheels bb on the shaft h. Between these wheels the
Prive 831

page_text: shaft carries a pinion a that gears with the toothed lifting rack i. The wheels bb
as also the pinions ce are so set relatively to each other that the teeth of the one
wheel and pinion are shifted somewhat round relatively to those of the other
wheel and pinion, so that a practically uniform effort of rotation is obtained and
all dead points are avoided. The pinion e and wheel d might of course be replaced
by a worm and worm wheel.
By means of the above described construction of the driving gear there will be
obtained, in addition to a quiet working, a perfectly reliable action of the jack;
the stability will be increased and the wear of the gear cousiderably diminished in
consequence of the uniform distribution of the pressure.
At the same time, the construction affords the advantage as compared with the
ordinary construction of jacks in which two pinions act simultaneously on the rack,
that the first tooth space of the rack can be situated a greater distance from the
claw, which is of importance, as in lifting the load the rack bar is subject to
compression at the claw, while at the teeth it is subject to a bending strain, and
consequently a breakage of the rack bar will be more readily prevented, the greater
is the distance between the top tooth space and the claw.
With this construction also, the length of the jack can be reduced without
reducing the extent of lift.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that which I
claim is
A lifting jack with toothed rack gear, wherein the transmission of power from
the second motion shaft is effected by two pinions ce gearing with the spur
wheels bb on the load shaft h, the teeth of one of the said spur wheels being
shifted round relatively to the teeth of the other, so as to produce a more uniform
rotation, and effect increased safety, and a decreased wear, substantially as
described.
Dated this 17th day of October 1892.
ABEL & IMRAY,
Agents for the Applicant.