A New or Improved Automatio Double Action Lift Cage Arrester.
Year: 1895

page_text: Date of Application, 6th Mar., 1895
Complete Specification Left, 4th Dec., 1895-Accepted, 4th Jan., 1896
PROVISIONAL SPECIFICATION.
A New or Improved Automatio Double Action Lift Cage Arrester.
HARRY ARTHUR WOOD MIDDLEDITCH Electrical Engineer Lyminster
Arundel Sussex do hereby declare the nature of this invoution to be as
follows:-
A mechanical device, composed of two iron boxes, telescoping into one another,
the top, or outside one, is fixed to the bottom of cage of lift; the bottom, or
inside one,
is fixed to top of ram; across each end of the bottom box is fixed
a spindle, and working on the said spindle, are two lever arms, extending the
full width between cage guides when not in action; in the centre of tho said
bottom box is a cylinder, having a piston, the piston rod, having a crosshead,
the crosshead connecting the two lever arms, the crosshead is drawn down by
two springs each side of cylinder. The piston is raised by the hydraulic power
conveyed by utilizing the ram or tube inside same.
March 5th 1895.
HARRY ARTHUR WOOD MIDDLEDITCH.
A New or Improved Automatio Double Action Lift Oage Arrester.
1, BARRY ARTHUR WOOD MIDDLEDITOH of Lyminster, Arundel, Sussex,
Electrical 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 :-
This invention relates to apparatus for sustaining the cages of lifts when the
fluid pressure underneath the ram which supports them is by accident withdrawn,
and consists in so arranging lever arms or catches that as soon as the pressure is
withdrawn, they engage with the sides of the lift shaft, aud prevent the cage from
falling to the bottom of it. Normally these arms are operated by springs, but the
arrangement of the two boxes sliding one within the other, secures the extension
of the lever arms or catches and their engagement with the walls of the lift shaft
even if the springs are broken.
In order that my invention may be fully understood and ascertained I append a
sheet of drawings in which:-
―1
Fig. 1 is a sectional elevation of a lift shaft and cage with my apparatus applied
thereto.
Figs. 2, 3, 1, 5, 6, and 7 are detail views.
A designates the sides of the lift shaft in which slides the lift cage B, this being
supported and operated by the ram C which works in a casing at the bottom of a
lift shaft in the ordinary manner. Up through the centre of the ram C passes a
tube or pipe c which is open at the bottom to the rain casing and at its upper end
to a cylinder D. The upper end of the ram is not attached directly to the lift cage
in the usual manner, but has formed integral with or fixed to it an inside box E
which is free to slide vertically inside an outer box G, this latter being rigidly
attached to the under side of the floor of the lift cage.

page_text: Passing through slots e in the sides of the inside cylinder E and pivoted at el
therein are two lever arms H, the outer ends h being chisel shaped so as to engage
the sides of the lift shaft, and the inner ends ¹ of which are connected to a cross-
head d that is fixed rigidly to the upper end of the piston rod d of a piston d
which slides in the cylinder D.
To the ends of the crosshead d or to the inner ends h of the lever arms H are
attached two springs h which are sufficiently strong to pull down the ends h¹ of
the lever arms when there is uo pressure in the cylinder D under the piston d, but
which are extended when the pressure in the ram casing is communicated to the
oylinder D by the tube c. gare two slits in the outside box G for a purpose which
will hereinafter be described.
The operation is as follows:-
When the normal pressure in the ram casing exists this is communicated by the
tube c to the cylinder D and pressing upwards the piston d, the rod d', and the
crosshead d, the inner ends of the levers H are lifted extending the springs
and causing the outer ends of the levers to assume the position shewn in the
drawings, preventing them from touching the sides of the lift shaft and leaving the
cago free to be moved up or down.
But should the pressure under the ram be suddenly removed leaving the cage
unsupported, the pressure in the cylinder D would be reduced correspondingly, and
the springs pulling down the piston and inner ends of the lever arms H would
cause the chisel pointed outer ends h of the latter to engage with the sides of the
lift shaft and prevent the cago from descending further.
The slits in the outer box G are so proportioned that should the springs h
break or give way, the ram with the inner box would (in case of the pressure
under the ram being removed) tend to fall quicker than the outer box G, and in so
falling would bring the underside of the lever arms H into contact with the lower
edges of the slits g. This would lift the outer ends and bring their chisel points
into contact with the sides of the lift cage in the same manner as the springs.
In some cases I apply a small valve to the cylinder D and so connect it that it
can be operated from the interior of the cage B.
In the drawings two lever arms are shown, but any convenient number may he
employed, and they may be attached in any suitable manner, so as to bring their
chisel pointed ends into contact either with the sides of the lift shaft or with racks
placed theroin.
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. An automatic lift cage arrestor in which the fluid pressure under the ram
normally operates lever arms or catches in such manner as to withdraw them from
contact with the sides of the lift shaft, or from engagement with racks fixed
thereto, but which when the pressure under the ram is withdrawn causes the ends
of such lever arms to engage with the sides of the lift shaft, or with racks fixed
thereto, in such manner as to support the cage, substantially as shewn and
described.
2. Au automatic lift cage arrestor consisting essentially of a piston sliding in a
cylinder and connected with the inner ends of spring retained lever arms in such
manner that the normal pressure under the ram, extends the springs, aud with-
draws the ends of the lever arins from contact with the sides of the lift shaft, but
when the pressure is removed allows the springs to force the ends of the lever
arms to engage with the sides of the lift shaft substantially as described and
shewn.
3. In an automatic lift cage arrestor the combination of the tube c communicating
with the ram casing, the cylinder D, the piston d, rod d', and crosshead d, the
levers H and the springs h', all constructed and operating substantially in the
manner and for the purpose described and shown.

page_text: 4. For use with au automatic lift cage arrestor as hereinbefore described and
shewn, the two boxes E and G with slits e and g, substantially as described and
Bhewn.
Dated this 30th day of November 1895.
HARRY ARTHUR WOOD MIDDLEDITCH.