Improvements in Hydraulic Hoisting Apparatus.
Year: 1893

page_text: Date of Application 18th Sept., 1893-Accepted, 21st Oct., 1893
COMPLETE SPECIFICATION.
Improvements in Hydraulic Hoisting Apparatus.
I, DAVID (CYNRIG) THOMAS, of Bronwydd, Llanishen, near Cardiff, in the
County of Glamorgan, Hoisting 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 an improvement in hydraulic hoisting apparatus, and
has for its object a novel method of constructing such apparatus in combination
with a rolling pinion and fixed rack so that a winding drum may be caused to
revolve in either direction for the purpose of raising, or lowering, a load.
In the accompanying drawings,
Fig. 1. is an elevation of hydraulic hoisting apparatus constructed according to
my invention; and Figs. 2, and 3, shew different positions of the ports in the
controlling valve.
A cylinder A is fixed vertically upon a foundation B, and has a stuffing box in a
cover at each end. Through these stuffing boxes a ram C passes, and on that part
of it within the cylinder A is fixed a piston D. The lower end of the ram C tits
into a cross-head E, which travels up and down between two planed surfaces, or
guides, in the foundation B. Upon a shaft F, which passes through the cross-
head E, is fixed a pinion G, and winding drum H. The shaft F is free to revolve
in the cross-head E, but the pinion G gears with a vertical rack J fixed to the
foundation B.
Kis the controlling valve, and is fixed so as to govern the admission and
discharge of water to and from the lower end of the cylinder A.
The action of the apparatus is as follows:-
The supply of water being always present upon the upper side of the piston D,
when the ports in the valve K are moved to the position shewn in Fig. 1. The
water under the said piston is discharged, and the piston and ram descend. The
downward motion of the ram and its cross-head E causes the shaft F, pinion G,
and drum H to revolve, and the load is raised by the winding rope.
When the ports in the valve K are as in Fig 2., the water is admitted to the
lower side of the piston D, and an equilibrium established, but the overbalance of
the load causing a displacement of the water above the piston the cross-head E,
shaft F, pinion G, drum H, ram C, and piston D return upwards, and the load
descends.
When the ports in the valve K are as in Fig. 3., the water cannot pass in, or
out, of the lower end of the cylinder A, and the load is arrested, or stopped.
A ram only may be used in lieu of ram and piston, but in such a case one port
and stuffing box only to the cylinder would be necessary.
If the weight of the ram, piston, cross-head, shaft, pinion, and drum are not
sufficient to properly counterbalance the empty cage of a hydraulic suspended lift,
weights L may be placed on the upper end of the ram C.
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. In hydraulic hoisting apparatus, the combination of a cylinder, fixed rack, and

page_text: guides with a ram, piston, cross-head, rolling pinion, shaft, and drum substantially
as described.
2. Hydraulic hoisting apparatus as described in the drawings.
Dated this 10th 1000
D. C. THOMAS.