Improvements in Lifting Jacks
Year: 1895

page_text: Date of Application, 30th Apr, 1895-Accepted 8th June 1895
Improvements in Lifting Jacks
I, JAMES HENRY SHERIDAN, of 121 Washington Street Flushing, Long
Island, State of New York, United States of America, Gentleman, do hereby
declare the nature of this invention and in what manner the same
performed, to be particularly described and ascertained in and by the following
statement
is to be
This invention relates to certain new and useful improvements in lifting jacks
and it has for its objects among others to provide a simple, strong and durable
and easily-operated lifting jack operated by worm and screw gear and adapted for
either foot or head lift and capable of rapid reverse movement for the purpose of
obtaining a new lift
The device embodies a stand with a screw shaft held therein, a worm gear with
depending tubular portion internally threaded to receive the said screw shaft and
an outer casing in which is mounted a worm shaft to co-operate with the worin gear
said casing carrying means for preventing rotary movement of the casing and yet
permitting rotary movement when it is desired to return the parts to their normal
position The outer casing is constructed to receive the weight either at its upper
end or upon a foot-lift near its lower end The outer casing is provided internally
with an annular ring between which and a nut on the tubular portion of the worm
gear are arranged balls forming a ball bearing The worm shaft is designed to be
actuated in any suitable way as for instance by a double-acting ratchet wrench
The parts are easily assembled and the device is capable of sustaining a great
weight and yet requiring but little power to operate the same
Other objects and advantages of the invention will hereinafter appear and the
novel features thereof will be specifically defined by the appended claims
The invention is clearly illustrated in the accompanying drawings, which, with
the letters of reference marked thereon form a part of this Specification and in
which
Fig is a central vertical section through my improved lifting jack
Fig 2 is a cross-section on the line 2-2 of Fig 1 looking downward
Like letters of reference indicate like parts in both of the views
Referring now to the details of the drawings by letter A designates the base or
stand which is tubular as shown and having upon its outer periphery a plurality of
longitudinal channels a, preferably four in number and which terminate at a short
distance from the ends of the tubular portion as seen in Fig 1
B is a screw shaft or rod arranged concentrically within the tubular portion of
the stand and having its lower end passed through the bottom thereof and there
provided with screw threads a¹ to receive the nut A' as seen in Fig 1 which bears
against the under side of the bottom portion of the stand or base and serves to
keep the screw rod or shaft securely in place
C is a worm gear having a tubular portion C¹ which is interiorly threaded as
seen in Fig 1 to receive the screw shaft or rod and fitted to slide within the
tubular portion of the stand
D is the outer case or cylinder fitted to slide over the tubular portion of the
base or stand and provided at its upper end with a removable cap Di Near its
lower end it is formed or provided with a lateral portion d, the upper face of which
is preferably square to receive the load to be lifted
E is a worm shaft mounted horizontally in bearings near the upper end of the

page_text: outer casing and carrying a worm E' meshing with the worm gear as seen best in
Fig 2 This shaft is preferably mounted in bearings in the outer case and the
removable cap or portion E removably held to the outer cise in any suitable
manner one or both ends of the shaft being extended and adapted to be rotated in
any uitable way is for instance by a double acting ratchet wrench The worm is
provided with balls at the ends as shown in Fig 2 to take the end thrust
Projecting inwardly from the inner wall of the outer casing near the upper end
thereof is a ring F which fits just beneath the worm gear as seen in Fig 1 and
upon the under side of which is a hardened steel ring G between which and a nut H
screwed onto the tubular portion of the gear are held the balls, as shown clearly
in Fig 1 In whichever direction the strain comes the pressure is equal upon
the balls
Near its lower end the outer case is formed with a chambered or hollow boss d'
in which is fitted a plunger I, the stem I' of which projects through a hole in the
removable cap of the said boss and it is provided with a knob or other device
by which it may be manipulated At the inner end of this plunge is a small
roller or wheel which is designed to travel in one of the channels of the tubular
portion of the stand A spring urges the plunger with its wheel inward
With the parts constructed and arranged as above described the operation is as
follows The weight to be lifted ma, be pliced either upon the 'upper end of the
outer case or upon the foot-lift d thereof The plunger is, by its spring, forced
into one of the channels of the tubular portion of the stand, and when the worm
shaft is turned it causes the worm gear to revolve, and this, by reason of the
ring F and the nut C causes the tubular portion of the gear and the outer casing
to be elevated simultaneously, being guided by the tubular portion of the stand and
the tubular portion of the gear working on the screw shafe on rod The parts are
returned to their normal position by pulling outward the plunger so its wheel or
roller is removed from the channel of the tubular portion of the stand and then
the weight of the parts will cause the same to revolve and move downwird, when
the roller of the plunger springs into one of the channels of the tubular portion
of the stand and the parts are ready to be again operated
Modifications in detail may be resorted to without departing from the spirit of
the invention or sacrificing any of its advantages
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1 The combination with the base with its sciew rod and tubular portion, of the
worm gear with interiorly threaded depending tubular portion the outer casing
with its worm shaft and intering, the nut on the tubular portion of the gear
and the balls between said nut and ring, sub tantially as specified
2 The combination with the base with tubular portion and screw rod, of the
worm gear with tubular portion, the outer casing with its worm shaft with balls
for taking the end thrust, the ing on the outer casing the nut on the tubular
portion of the gear, the balls between the nut and ring, and means for preventing
rotation of the outer case, as set forth
3 The combination with the base with its tubular portion with channels, of the
outer casing with hollow boss with removable cap, the spring-actuated plunger in
said boss, and a roller at the inner end thereof to travel in the channels,
substantially as specified
Dated this 30th day of April 1895
BOULT & WADE,
Agents for the Applicant