Improvements in Hydraulic Lifts.
Year: 1891

page_text: Date of Application, 10th Mar., 1891-Accepted, 2nd May, 1891
Improvements in Hydraulic Lifts.
A communication from ABEL PIFRE, of 95, Boulevard Beaumarchais, Paris, in the
Republic of France.
1, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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 improved hydraulic lifts presenting a number of special
advantages viz. counterbalancing dead weights; preventing accidents from breaking
by avoiding the shocks connected therewith; and facilitating the operation and
control, all of which purposes are attained by the agency of water under pressure.
The arrangements contrived with a view to obtaining this result are shown in the
accompanying drawings in which
Fig. 1 is a vertical section of the lift, and
Fig. 2 a plan thereof the upper pulleys being removed.
This lift consists of a hydraulic motor engine operating a cable the pull or strain
of which is transmitted to the cage or platform and adapted to slide between con-
venient vertical guides holding it in the proper position. This cage is connected
to the cable by means of a safety brake or system of toggle levers adapted to
prevent its fall in case any one of the means of suspension used should break.
will now proceed to describe in detail the various parts of which this improved
mechanism is composed and then point out the advantages thereof.
I
The hydraulic motor consists of a cylinder A wherein a piston or plunger Bis
adapted to move and which passes through a leather or other packing and its
head is guided in its movement by uprights C supporting the cylinder the plunger
being provided with a pitch wheel or pulley D engaging with a pitch-chain E
one end of which is attached to the cylinder A. while the other is passed over a
toothed pinion F and terminates in a weight G to keep the chain always in a state
of tension. The pinion F is secured to the same shaft which carries the barrel
or drum H to which the driving cable I is fixed and whereon it is to be wound.
This cable I passes over a pulley J situated in the upper portion of the space in
which the lift cage is arranged, while its other end is attached to the toggle levers K
firmly secured to the cage or platform L.
The system of toggle levers K consists of a yoke M the lower portion of which
is connected to the cage while the space between the two legs or branches is filled
up by a spring N. This spring may consist either of bent plates or strips or of a
series of elastic washers or be wound spirally, its shape or system being in fact
optional. The spring N exercises its action between the top of the yoke M and
sleeve bracket P, which is connected by links Q to other links R and it tends in
expanding to lower the said bracket P towards the cage. The links R are at their
upper ends connected with an attachment device S provided at the end of the cable
while their opposite ends join the levers T pivoted at U. The pivots or spindles U
are connected with the cage by their supporting brackets V and are rigidly keyed
to these supports. They are screw threaded in two opposite directions so that the
effect of the levers T rotating upon their respective pivots is that they are in pairs
brought nearer together or farther apart as the case may be. So that should the
cable become loose in consequence of the breakage of either itself or any of the
devices of suspension the spring N will lower the bracket P and turn the levers T
on their pivots U. These parts T consequently draw closer to each other and
thus compress the guides or rails W between their ends. When once they are
thus engaged the growing downward tendency of the cage brings them more and

page_text: more nearer to each other and in the same proportion increases the pressure upon
the guides W until the cage stops. The said guides W are made of iron and may
be of either cylindrical or any other section:
The lift is operated as follows:-
A water distributor X actuated by means of a rod X' or any other suitable device
connects either the conduit Y supplying the water under pressure with the conduit Z
leading to the driving cylinder A, or the conduit Z with another conduit Z' leading
to a sewer or any discharge arrangement. When the conduits Y and Z are
connected the water in pressing upon the piston B causes it to descend and to
pull the pitch chain which through the medium of the pinion F causes the drum H
to rotate and the driving cable I to be wound on its barrel. This causes the cage
to rise until it is stopped on the desired floor or landing by the action of the
distributor X operated either by the user at his will or automatically, when all the
conduits Y Z and Z' are cut off from each other. When on the contrary the distributor
is operated in such a manner as to connect the conduits Z and Z the weight of the
cage in straining or tightening the cable I upwinds the same from the barrel H,
at the same time the pinion exercises its pull upon the pitch chain which causes
the piston B to move back in to the cylinder A. When the cage stops in its
downward movement it cuts off all the conduits in the same manner. The shape or
construction of the distributor X is optional.
The operating device of the said distributor mainly consists of a cylinder a in
which moves a piston . Two conduits c and d connect the top and bottom of this
cylinder a with the interior of a closed chamber e which is kept constantly filled
with water under pressure with which it is supplied by a conduit f. Within this
chamber e there is a slide-valve covering a conduit leading to the outlet or
escape-orifice, which slide-valvey may be so arranged as to connect either of the
conduits dore with the outlet pipe . The piston rod is connected with a lever j
9
of the distributor X of the lift. It will be understood that when the slide valve
connects the conduite with conduit the pressure of the water filling the chamber a
causes the piston to rise; and when the connection is similarly opened between
conduits d and the piston will descend. According as it moves in either of these
two directions the lever is caused to rise or sink. The slide valve is operated
by a T-shaped lever in the ends of the two horizontal arms of which are passed
the ends of a cord which in the upper part of the shaft or space occupied by
the lift passes over a pulley m. Two stops n and n' are provided at the cord ends
so that when the part 7 is drawn upwardly the stop n will actuate the lever k and
move the slide valve from right to left (in the drawing) and when the part is
drawn downwards it is the stop that actuates the lever and consequently causes
the slide valve to move from left to right. The two cord ends and are also
provided with weights and p¹ which are supported by a fixed piece which
keeps them from descending lower than required and which when either of the
cord ends or is drawn are displaced by the stops and respectively. Each
of these weights p and p' is so arranged as to be capable of restoring the lever k
to its horizontal position when it is no longer otherwise acted upon and thus to
cause the slide-valve g also to resume its normal position in the centre of its
chamber e.
g
The operation resulting from this arrangement is as follows:-When it is desired
to cause the lift to rise the cord end 7 is drawn upward. The weight p is thus raised
and the slide g connects the conduit d with the outlet. The piston is now made
to descend and the distributor is brought in the position compatible with the rising
of the lift. The lever is pivoted to the rod extending from the top to the
bottom of the cage-shaft and provided with special stops, the result is that when
the said cage has reached the floor or landing where it is desired to stop it engages
the corresponding stop of the rods and brings the lever j back to the horizontal
position whereby the distributor is closed and the lift effectually stopped.
Besides when the cord is no longer drawn upwardly as described it resumes its
normal position under the action of the weight p and thereby causes the slide-valve g

page_text: b
also to take up its position in the middle of the chamber c. When therefore the
age makes the lever j resume its horizontal position through the medium of the
rods the piston 6 may without hindrance re-ascend under the action of the said
lever since the conduits c and d are then connected through the medium of the
j
chamber e. It will be understood that if, on the contrary the lift be desired to
descend it is only necessary to put the cord 2 downwardly or what amounts to the
same thing, to draw the other cord in the opposite direction. Instead of a cord
a rigid rod may be used which may be provided with handles at the different floors
so as to enable the lift to be operated from outside. As to the cords it will be
seen that it extends across the cage which similarly enables the lift to be operated
from within.
The peculiarities and advantages of this system of lift may be described as
follows:-
―:
As regards the motor :-The piston B being of the nature of a plunger, the joint
at the entrance of the cylinder may be readily controlled, tightened and made
watertight.
The weight of the piston B which may be regulated at will by making the body
thereof hollow and filling it with counterweights of cast iron or lead, serves to
counterbalance the dead weight of the cage save the excess of weight necessary for
its descent. The apparatus is therefore counterbalanced so that the consumption
of water is reduced to the minimum strictly necessary. Another very great
advantage lies in the peculiar arrangement of the different parts of the motor.
In order that the motor may be as little cumbersome as possible and easily
located in its place it is necessary that its piston-stroke should represent the
smallest possible fraction of the path travelled over by the cage. In other apparatus
the cylinder is either connected with the tackle or with a piston fitted with ԷՆ rack
gearing with a pinion secured on the same shaft on which is mounted the drum upon
which the cable is wound. In the case of the tackle cylinder if it is desired for
example that the piston stroke should bear to the path of the cage the relation
of 1: 10 five pulleys are necessary turning upon the same shaft which involves very
considerable tensions and excessive friction. And it is also necessary in that case
to use a cable of small diameter so that it may be wound upon all of those pulleys
without an excessive strain. In the system here described on the contrary the drum
on which the cable is wound being always of a comparatively large diameter enables
cables of large size to be employed thus notably increasing the safety of the driving
mechanism. In the case of the piston and rack arrangement the latter acting
directly upon the pinion secured to the shaft of the drum whereon the cable is
wound, it is necessary that the said pinion may be ten times smaller than the drum.
So that it becomes necessary to use a drum of a very considerable diameter to be
able to employ a pinion of sufficiently large size, considering the enormous strain
exercised upon it by the rack. Besides the pinion being necessarily of small
diameter has only one of its teeth engaged with the rack at one time and this tooth
(which consequently must be exceedingly strong) is operated at one time at its
base and at another at its apex whence result differences of strain having the most
objectionable effect. Whereas the present system offers the following advantages
over the rack mechanism :-In the first place owing to the method of attachment
of the pitch chain and to its passing over the pulley D a tackle is obtained which
in order to produce a movement of the cage ten times larger than the piston stroke,
reduces the ratio of the drum to the pinion secured to the shaft to 5 : 1 which
enables the pinion to be of a comparatively large diameter and have a greater
number of teeth. On the other hand as the pitch chain covers one half of the
circumference of the pinion half of the teeth of the same are in gear with it at the
same time, which reduces the strain on each tooth to a minimum and makes it
perfectly uniform. By these means all parts are rendered more durable and the
working capacity and safety of the lift are notably increased.
As regards the system of toggle levers in this system of lift their effect instead
of being due to the wedging action of cams, to grips driven into wooden guides, or

page_text: to wedges engaging with the teeth of racks (which latter system is chiefly objection-
able because it stops the lift by a violent shock, necessarily damaging certain parts
of the mechanism and indeed apt to cause more serious accidents) is here produced
by a gradually increasing pressure upon smooth metal guides whereby the frictional
resistance accordingly grows more and more powerful until it brings the lift to a
stop the whole operation occupying a sufficient space of time to avoid instantaneous
shocks and the attendant inconveniences.
In point of appearance again as the guides mentioned above consist of smooth
metal columns of but few inches diameter instead of being formed of bulky pieces
of wood (as is the case where toggle levers with grips are employed) or of unsightly
uprights with racks they may be arranged in any staircase without injury to the
general ornamental effect of the same.
If necessary the piston of the hydraulic engine may be provided with an internal
packing and one or two rods arranged externally in which case the counterweight
necessary to counterbalance the dead weight would have to be applied to such rod
or rods.
When very great strains are required or for other purposes two or more
pinions and a corresponding number of pitch chains may be provided. The driving
cable may be either round or flat or else formed by the juxtaposition of a number
of cables or may be a chain. The number and size of the parts forming the system
of toggle levers may vary according to local requirements. And lastly the dis-
tributor and the operating mechanism may be arranged according to any suitable.
system or method.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is :-
An improved hydraulic lift consisting of a piston driven by hydraulic pressure
acting through the medium of one or more pulleys and pitch chains upon the cable
carrying the cage or platform of a system of toggle levers the parts of which act
upon smooth guides and which if the cable should break grasp the said guides
between pairs of jaws, of a distributor supplying the fluid pressure in the space
below the piston and capable of being operated without strain owing to a small
piston and a chamber which receives the fluid under pressure and distributes it by
means of a slide-valve operated by hand through the medium of cords or the like
the whole enabling the dead weight to be counterbalanced by the piston of the
hydraulic motor cylinder facilitating an easy and even operation of the mechanism
and permitting the lift to stop without abrupt movement or shock in case the cable
carrying the cage should break substantially as described.
Dated this 10th day of March 1891.
W. P. THOMPSON & BOULT,
Agents for the Applicant.