Improvements in Lifting Jacks.
Year: 1890

page_text: Date of Application, 11th Nov., 1890-Accepted, 28th Feb. 1891
COMPLETE SPECIFICATION.
Improvements in Lifting Jacks.
I, FREDERIK TISCHER, of 195, West Kinney Street, in the City of
Newark, County of Essex, United States of America, Machinist, 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:-
The herein described invention relates to improvements in gear screw lifting jacks
and it consists in the peculiar construction and combination of parts as will be
hereinafter more fully described and finally embodied in the several clauses of
the claim.
The invention is illustrated in the drawings herewith accompanying, in which
similar letters of reference are employed to indicate corresponding parts in each of
the several views.
In said drawings
Fig. 1 is a front elevation of my improved lifting jack;
Fig. 2 is a side elevation of the same and
Fig. 3 is a view similar to that shown in Fig. 1, and illustrating the construction
of the opposite side of the jack and
Fig. 4 is a horizontal section taken on lineæ in Fig. 2;
Fig. 5 is a vertical section of the lifting jack and
Fig. 6 is a view similar to that shown in Fig. 1, but with the gear protecting
plate removed;
Fig. 7 is a plan view showing the turn table with its rollers, the top plate being
removed;
Fig. 8 is a sectional view through line t of Fig. 7 with the top plate on.
In said drawings a indicates the base which is provided, preferably near the
upper part thereof, with an annular shoulder a¹ and around the upper part of said
base arranged the sleeve a resting upon said shoulder a¹ and adapted to rotate
thereupon.
From Fig. 5 it will be seen that the base a is tubular, being provided on the back
thereof with an upwardly projecting opening a³, and within the hollow part of the
base I have arranged the male screw provided with a step b', projecting out through
said opening a³ as illustrated. Said screw is provided at the top thereof with a head b
which may be secured thereon in any convenient manner.
Directly upon the upper end of the base a is arranged a turn table c which
consists of a circular plate or disc c¹ placed directly upon said upper end of the base
and arranged within an upwardly projecting flange at on the sleeve a² as clearly
llustrated in Fig. 5.
The upper side of said disc e¹ is inclined upwardly as shown more especially
n Fig. 8 and upon the same is placed a plate c² provided with openings or
ockets in which are arranged small steel rollers c which are tapered as
hewn. The opposite sides of the disc care inclined toward each other and
oward the centre of said disc and the rollers are in the form of a truncated cone.
Upon these rollers is arranged another plate e which is similar in cross section to
he plate c. The turn table is provided with a centrally arranged perforation co
or arranging the same around the screw b.
As will be seen from Figs. 1, 2, 3, 5 the upper end of the sleeve a² is cup shaped
ta and within the same I have arranged a female screw or nut d provided with
eth d' on its under side. The male screw works through a threaded perforation d²
said nut.
From Figs. 5 & 6 it will be seen that I have provided the sleeve a² with a
Price 1

page_text: chambered portion in which is arranged a gear e meshing with said teeth on the
nut d and also a gear el meshing with the smaller pinion e² as shown. Said gear
are provided with proper axles working in bearing a and a' in the sleeve a² and
also in bearings in the protecting shield or plate secured over said chambered
portion by means of screws f¹. Said shield is provided with an upwardly pro-
jecting lip which covers the greater part of one side of the mit d. From this
construction it will be evident that the gear mechanism is entirely protected
and no dirt or stones can fall between the teeth of the gear and thus render the
jack useless.
The axles of the gear project out beyond the plate and are squared to
receive a crank or handle. The crank can be placed on either end of the axles,
raising the screw and its head much faster when applied to the large gear
wheel e' as will be evident, but receiving the greater power when applied to the
other gear.
Another great advantage is obtained by making the sleeve a² with the
upwardly projecting and cup shaped shoulder as whereby the teeth d' are entirely
within the machine and cannot come in contact with the load resting on the
step b
A set screw a extending into an annular groove a in the top part of the
base, holds the sleeve in position thereon, still allowing the latter to turn on
the shoulder a'.
If desirable another set screw ao can be arranged on one of the sides of
the sleeves, as in Figs. 1 & 2 which can be tightened up against the side of the
base a whereby the sleeve is rigidly held and prevented from turning on the
shoulder a¹.
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 as my invention and desire to secure by Patent is :-
1. In a lifting jack the combination with a hollow base, a lifting screw provided
with a step, a turn table on the upper part of said base, a cup shaped sleeve
arranged on a shoulder on said base provided with one or more set screws, a nut
working on said screw and provided with teeth which are entirely protected by said
cup shaped sleeve, gear mechanism for operating said nut, and a protecting plate
provided with a lip, as and for the purpose set forth.
2. In a lifting jack the combination of a hollow base, a lifting screw, a turn table
upon the upper part of said base, a sleeve surrounding the base and provided with
one or more set screws as set forth, and means for raising and lowering said lifting
screw, as and for the purposes set forth.
3. In a lifting jack the combination of a hollow base, a lifting screw, a turn table
upon the upper part of said base, a sleeve surrounding said table provided with one
or more set screws as set forth, a nut on said screw provided with teeth on its under
side, a gear e meshing therewith, gears e¹ and e² and plate fall of said parts being
arranged as and for the purpose set forth.
Dated this 11th day of November 1890.
C. R. BONNE & Co.,
41, Eastcheap, London, E.C., Authorised Patent and Trade Mark Agents.