Improvements in Lifting Jacks.
Year: 1893

page_text: Date of Application, 5th Dec., 1893-Accepted, 17th Feb., 1894
Improvements in Lifting Jacks.
I, ERNST HELLER, of Burtscheid, near Aix-la-Chapelle in the Empire of
Germany, Engineer, 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:-
My invention relates to lifting jacks and comprises the improvements hereinafter
described.
In the accompanying drawing,-
Figures and 2 are respectively front and side elevations of my improved
jack:
Figure 3 is a vertical section on the line E F, Figure 1; and,
Figures and 5 are horizontal sections on the lines A B of Figure 3 and
CD of Figure 1 respectively:
Figures 6, 7 and 8 shew details of the driving mechanism.
The lifting-bar of my improved jack consists of two parts A1, A2, Figure 6,.
which are provided at the ends adjacent to each other with teeth a as shown in
Figure 6 or with roller studs a' as shewn in Figures 7 and 8. These teeth or studs
engage in a spiral groove b in a disc B in such a manner that when the said disc B,.
which is capable of rotation and arranged in a casing C Figures 1-3 enclosing the
bars A1 and A2, is rotated the casing C with the diss B and bar A' is raised or
lowered relatively with the lower bar A, whilst the upper bar A is at the same
time moyed up or down independently of the casing the same distance that the
casing C is moved relatively with the bar A so that the lift of the jack is equal
to the lift of the casing C plus the lift of the upper bar A' independently of the
casing.
My improved jack possesses the advantages that the rod A' only moves out of
the casing a distance equal to half the lift of the jack C and that by employing the
spiral groove in combination with the teeth a or studs on the bars A₁ and A
the load resting on the bar is held at any height with absolute safety whereby
the employment of a ratchet wheel and pawl or other safety appliance is not
necessary.
The rotary motion of the disc B is effected by the handle D, Figure 1, through
the medium of the gear wheels e,,g, and the intermediate wheels and which
engage in the toothed rim of the disc B, the said handle and gear wheels being
carried upon bolts 0,7 fixed to the cover F which closes the casing Cover the
disc B, the said cover being fastened on the casing C by means of the bolt o and
the pin, Figures 3 and 5.
It is obvious that the driving mechanism which serves to move the disc B can:
be formed in different manners to suit varying requirements for instance in a jack
designed for lifting small loads the driving wheel e, Figure 1, can engage directly
with the toothed rim of the disc B. For lifting heavy loads several gear-wheels.
can be employed and in case of necessity a worm and worm-wheel alone or in
combination with one or more gear-wheels can be arranged. The periphery of the
disc B can also be formed as a worm-wheel and the worm serving to drive the same.
carried in the casing C.
The claw E can be fastened to the upper rod A' of the jack as shewn in
Figures 3, 4 and 5, in which case it slides in a groove in the bar A2, or it can be
fastened to the casing C. In the first case it moves the whole lift of the jack
whilst in the latter case it moves only half the lift, that is only the lift of the:
casing C.

page_text: 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. A lifting jack in which the lifting-bar consists of a movable part A' and a
fixed part A, both of which parts at the adjacent ends are provided with teeth or
studs engaging in a spiral groove of a disc B, the rotation of which moves the
casing carrying the said disc together with the movable part' A' of the lifting-bar
relatively with the fixed part A2 of the said bar whilst at the same time the
movable part A is moved independently so that the total lift of the jack is equal
to the lift of the casing containing the disc plus the independent lift of the movable
part A of the lifting-bar, substantially as described.
2. A lifting jack of the kind indicated in the preceding claiming clause in which
the grooved disc B receives its motion from a handle D having the gear wheel e
which transmits its rotation to the gear-wheels and and the intermediate
wheels and which engage in the toothed rim of the disc B, the said handle
and gear-wheels being held in position by means of the bolts o, p, q secured to
the cover which closes the casing C, the said cover being fastened by means
of the bolt o and the pin to the said casing, substantially as described.
3. A lifting jack of the kind indicated in Claim 1 in which the claw E is fastened
to the upper part A' of the lifting bar and slides in a groove in the lower part A²
of the said bar, substantially as described.
i
Dated this 5th day of Decauhan.1002
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.