A Improvements in Lifting Jacks.
Year: 1899

page_text: A
Improvements in Lifting Jacks.
We, ANDRÉ LOUIS MARCOTTE and MAURICE ALFRED LEGROS, both of Les Iris,
Avon (Seine et Marne), in the Republic of France, Engineers, do hereby declare the
nature of this invention to be as follows:-
This invention relates to a novel form of lifting jack and consists essentially
of two cylinders which are internally and oppositely screw-threaded.
The lower cylinder of the two is provided with a foot by means of which it
rests upon the ground. The upper cylinder terminates at its upper portion in a
head which is applied beneath the objects which it is desired to lift.
Two screws formed upon the same rod gear respectively with the internally
screw threaded portions of the two cylinders.
At its middle point this rod is provided with a ratchet or cog wheel, which,
as is hereinafter explained, enables the jack to be operated.
The socket, constituted by two parts connected one with the other by means
of screws, surrounds the said ratchet or cog. This socket is recessed in its
middle portion into which extends a prolongation upon which is applied a
spring formed by a blade which is maintained applied against the prolongation
by means of a screw.
Two pawls are adapted to oscillate around spindles traversing the socket.
The two pawls are so arranged as to alternately engage the teeth of the ratchet
or cog
If the operator, by means of the handle, imparts a reciprocating movement
to the socket, the pawl will actuate the cog during the first period of the move-
ment and will cause the screws to rotate in the cylinders. The part head will
therefore rise and lift the object beneath which it has been applied. During
the second period of the movement, the pawl will slide over the teeth of the
cog or ratchet and this latter will remain motionless. The movement is con-
tinued as long as required.
In order to lower the object, the operator has only to cause the pawl to turn
about its spindle in such a manner as to withdraw from engagement with the
teeth of the cog or ratchet the projecting portion of this pawl. This movement
is rendered possible by the flexibility of the flat spring and the pawl is main-
tained in position by this spring. The operator will then cause the other pawl
to rotate upon its axis so that the projection portion of this pawl engages with
the teeth of the cog or ratchet. By imparting to the socket the same reciprocat-
ing movement, the screws will be caused to rotate in the reverse direction, and
the upper part in descending will at the same time permit the object beneath
which it is placed to descend.
In order that the appliance may occupy less space for the purpose of facilitat-
ing its transport, more particularly in motor road vehicles, the handle terminates

page_text: in a screw threaded portion which screws into a screw threaded recess formed
in the socket.
Dated this 2nd day of August 1899.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.
We, ANDRÉ LOUIS MARCOTTE and MAURICE ALFRED LEGROS, both of Les Iris,
Avon (Seine et Marne), in the Republic of France, Engineers, 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 a novel form of lifting jack, and in order that the
constructions thereof may be readily understood I will describe the same fully
with reference to the accompanying drawings in which:
Figure 1 is an elevation of my improved lifting jack in an operative position.
Figure 2 is a plan view of the same.
Figure 3 shows in detail the different parts of which the jack consists.
Figure 4 is an enlarged sectional view of the means employed for actuating
my improved device, and
Figure 5 is a section of the same on line A-B Figure 4.
The jack consists essentially of two cylinders
and oppositely screw-threaded.
and b which are internally
The cylinder a is provided with a foot c by means of which it rests upon the
ground. The cylinder 6 terminates at its upper portion in a head d which is
applied beneath the objects which it is desired to lift.
Two oppositely threaded screws e and f formed upon the same rod, gear
respectively with the internally screw threaded portions of the cylinders
and b.
fl
At its middle point this rod is provided with a ratchet or cog g, which, as is
hereinafter explained, enables the jack to be operated.
The socket h, consisting of two parts, connected one with the other by means
of screws, surrounds the said ratchet or cog y (see Figures 4 and 5). This
socket his recessed in its middle portion into which extends a prolongation
which carries a blade spring which is maintained against the said part i by
means of a screw j¹.
Two pawls and are adapted to oscillate around spindles and mounted
in the socket h. The two pawls are so arranged as to alternately engage the
teeth of the ratchet or cog g
As shown in Figure 5 the pawl engages the ratchet y with its nose. If
the operator, by means of the handle m, imparts a reciprocating movement
to the socket h, the pawl k will actuate the ratchet g during the first period
of the movement, and will cause the screws e and f to rotate in the cylinders a
and b. The head d will therefore be raised and lift the object beneath which
it has been applied. During the second period of the movement, the pawl k
will slide over the teeth of the ratchet or cog g and this latter will remain
motionless. The movement is continued as long as required.
In order to lower the object, the operator has only to cause the pawl k to
turn about its spindle in such a manner as to disengage it from the teeth of
the ratchet g. This movement is rendered possible by the flexibility of the

page_text: blade spring, and the pawl is thus maintained in position. The operator will
then cause the other pawl to rotate upon its axis so that the projecting
portion of this pawl engages with the teeth of the ratchet g. By imparting to
the socket the same reciprocating movement, the screws e and f will be caused
to rotate in the reverse direction, and the part in descending will at the same
time permit the object beneath which it is placed to descend.
In order that the appliance may occupy less space for the purpose of facilitating
removal from place to place more particularly in motor road vehicles, the
handle m terminates in a screw threaded portion which screws into a screw
threaded recess formed in the socket h.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that
what we claim is:-
In a lifting jack the combination of two internally and oppositely screw
threaded cylinders one of which is provided with a foot supporting the appliance,
whilst the other is applied beneath the object to be lifted, of a rod, the two
extremities of which are provided with screw threads of opposite direction adapted
to engage in the screw threaded portion of the two cylinders; a ratchet or cog on
said rod, a socket within which are arranged two pawls capable of displacement
in such a manner as to engage alternately with the teeth of the ratchet or cog,
such pawls being maintained in position by means of a flexible flat spring rigidly
attached to the socket, a removable handle adapted to impart a reciprocating
movement to said socket substantially as herein before described and illustrated
by the accompanying drawings.
Dated this 22nd day of March. 1900
HASELTINE, LAKE & Co.,
45. Southampton Buildings, London, W.C.,
Agents for the Applicants.