Improvements in Mechanism for Converting Rectilinear Motion into Rotary Motion.
Year: 1893

page_text: Date of Application, 15th Sept., 1893-Accepted, 11th Nov., 1893
COMPLETE SPECIFICATION.
Improvements in Mechanism for Converting Rectilinear Motion into
Rotary Motion.
I, ALEXANDRE PHILIPPE DÉSIRÉ LEVAL, Accountant of 16 Rue sur l'eau
Verdun, Department of the Meuse, France, 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 mechanisms for converting reciprocating rectilinear
motion into continuous rotary motion and consists in improvements on the
mechanisms described in my Specification No. 20504 of 1892.
In the arrange-
ment described in said Specification two diametrically opposite crank pins have
connecting rods attached to them, the other ends of which are constrained to move
rectilinearly and have links of equal length attached to them joined at their other
ends and rectilinearly guided in a line vertical to the line of movement of the
connecting rod ends, and by imparting a reciprocating motion to the joint of said
links the crank shaft is rotated. This arrangement has the drawback that twice in
every revolution both crank pins and connecting rods arrive simultaneously at their
dead centres and require the assistance of a flywheel or its equivalent to continue
the motion, and that the motion cannot be started in any position. The object of
my improvements is to overcome this defect which I do by placing the cranks at
right angles to each other and connecting the rectilinearly guided outer end of
the connecting rods to links of equal length rectilinearly guided in a line or in
parallel lines vertical to the connecting rod guides but not joined together at their
upper ends, and.imparting to these upper ends a vertical motion successively.
On the sheet of drawings appended hereunto,
Fig. 1, 2, 3, and 4 show diagrams of the mechanism or motion in four different
positions.
Fig. 5 shows a side view, Fig. 6 a plan and Fig. 7 a vertical section of an
arrangement of mechanism embodying the principle of the motion as stated
above.
Referring first to the diagrams: O represents an axis capable of rotation; OR
and OP two cranks or their equivalent at a right angle to each other. R and P
are connected to points C and D by stiff rods or their equivalents R C and PD
articulated at C and D, the points C and D being constrained to move in the
line XOX. C and D are connected by stiff links CA and D B of equal length
articulated at C and D to points A and B, these being constrained to move in the
line OY perpendicularly to XO X. Assuming the parts to be in the positions
shewn on Fig. I and a force applied to B forcing it towards the centre, the point D
will slide outwards and pull the crank P round into the position shewn by Fig. 2,
the crank OR assuming a vertical position. If the force is now transfered to the
point A, the point C will be similarly forced outwards and the rotation of the
axis continued till the parts arrive in the position F3, when the axis has made
half a revolution. The second half revolution may be produced by reversing the
direction of the force and pulling the point B Fig. 3 outwards till position Fig. 4
is reached and then transferring the pull to the point A Fig. 4, which will return
the parts to the position Fig. 1. Preferably however I arrange on the axis O, a
second set of parts with cranks diametrically opposite to the first set, so that when
the first pair of cranks has been turned from position Fig. I to position Fig. 3, by
bushing points B and A successively towards the centre, the second pair of cranks
as assumed the position Fig. 1 and the rotation of the axis is continued by
depressing the end of the respective links successively towards the centre. With
Tu 017

page_text: this arrangement one of the cranks will relatively to the rod attached to it be
always in a favourable position for starting the motion. Instead of moving in one
line, the points A B may be arranged to move in parallel lines equidistant from
the extreme positions of points C and D.
1)
Figs. 5 to 7 show how this method of converting rectilinear into rotary motion
may be carried out in practice. In a frame constructed in any suitable way a
four throw crank shaft is supported in bearings, each pair of cranks being actuated
in the following manner: To the pins and of cranks and p connecting
rods mandare respectively attached, the other ends of the connecting rods being
joined by pins ed to links ik, said links being ma le double or in pairs, one on each
side of the frame. The pins and d carry rollers guided in horizontal
slots ed of the frame. The links are attached at their upper ends by pivots
or their equivalents a, b, to blocks a or their equivalents which move in vertical
slots ss of the frame f. To the frame sile a treadle is held by screws t¹² passing
through slots and carrying friction rollers or by other suitable means so that it
can slide along the frame. In the treadle a slot t³ is formed embracing the block a¹;
a stud is fixed on the treadle on which a trigger is hinged, a peg 2 fixed to said
trigger entering a slot i inclined in the lower part which is formed in the frame.
On the pivot a bent latch g is hinged resting upon a ledge of the block b¹ so
that it can turn upwards; a spring may be used to hold it down upon said ledge.
A similar set of parts is arranged in connection with the second pair of cranks on
the opposite side of the frame 7.
The action of this mechanism is as follows: The parts being in the positions
shewn (corresponding with the diagram Fig. 1) and the treadle & depressed by the
foot, the trigger will press upon the latch and block and push it down,
whereby the pin d is pushed outwards and the crank p turned thereby as indicated
by the arrow. When the crank pin has arrived at its dead centre and the parts
have assumed the positions corresponding with diagram Fig. 2, the inclined part
of slot has moved the peg and trigger to the left so that it slips off the latch g.
At the same time the top of slot 2 comes into contact with the top of block at and
as the treadle is further depressed, the pin e is forced outwards and the crank
turned till the parts assume the positions corresponding with diagram Fig. 3.
The treadle on the opposite side of the frame is then depressed, the parts on that
side being at the start in the position corresponding with diagram Fig. 1, and
operated in the same way as herein before described, whereby the revolution of the
crankshaft is completed. During this second half revolution the links and treadle
first depressed are raised up again, successively to the positions corresponding with
diagrams Fig. 4 and 1, the treadle being further lifted to the position shown on
Figs. 5 and 7 by the spring u. In moving upwards the trigger has to pass the
latch 9 for which purpose the latch is hinged on the pin as described, so that it
can be turned up by the nose of the trigger and drop down again after the trigger
passed upon the ledge by its weight or pressed by a spring.
1,2
The mechanism described may be used for propelling velocipedes and similar
machines the middle part of the crank shaft o carrying the wheel hub, or the motion
of the crankshaft may be transmitted by means of chain pulleys and chain or other
suitable gearing to the wheel hub or axle. The details of the arrangement may be
varied from those shewn on the drawings according to the position and purpose in
and for which the mechanism is applied.
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 arrangement of mechanism for converting rectilinear motion into rotary
motion consisting of the combination of two links of equal length guided at one end
in parallel lines and at the other in a line at a right angle to the former, connecting
rods attached to said other ends and to two cranks placed at a right angle to each
other, and means for applying force successively to the ends of said links guided in.

page_text: parallel lines, substantially as hereinbefore described and illustrated by the
drawings.
2. The arrangement or combination of two sets of mechanism as claimed in the
preceding claim acting on one crankshaft alternatively substantially as herein-
before described and illustrated by the drawings.
3. The arrangement of mechanism or combination of parts substantially as
hereinbefore described with reference to Figs. 5, 6 and 7 of the drawings.
Dated this 8th day of Sentember 1893
R. J. URQUHART,
57, Barton Arcade, Manchester, and 5, Clayton Square, Liverpool,
Consulting Engineer and Patent Agent.