Improvements in and relating to the Packing of Pistons for Hoists or other Hydraulic Purposes.
Year: 1892

page_text: Date of Application, 14th May, 1892
Complete Specification Left, 13th Feb., 1893-Accepted, 15th Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Packing of Pistons for Hoists
or other Hydraulic Purposes.
I, JOHN ALEXANDER STEVEN, of 12 Royal Crescent, Glasgow, Lanarkshire,
Engineer, do hereby declare the nature of my invention to be as follows:-
This invention has reference to and comprises a new or improved mode and
means of packing pistons for hoists, rams, or other hydraulic purposes, and which
will enable the pistons to work fluid tight without attention or repair for a much
longer period of time than heretofore.
66
As applied to the piston of an hydraulic hoist, where the pressure water acts
downwards from above the piston to raise the load, the improvements consist in
fitting an annular ring of vulcanized india-rubber or other elastic material on the
inside surface of the usual cotton or hemp packing material pressing against the
hydraulic cylinder. This india-rubber would be formed of a doubled-up or
swan bill "shape turned inwards at its lower end, and have a small annular india-
rubber ring inserted and pressing between the two duplex parts. And another
india-rubber or elastic ring would be fitted to act near the upper part of the main
ring to press between its inner surface and the metallic part of the piston in which
it is embedded. A narrow water channel way or duct would lead from the top of
the piston with branches for the pressure water to act on the inner surface of the
last mentioned rubber ring, and in the annular space formed between the inner
surface of the main rubber ring and the inner metallic part of the piston, so as to
press on the elastic medium and through it retain the hemp or cotton packing
material always as a substantial fluid tight joint between the piston and cylinder.
Dated the 13th Mow 1809
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improvements in and relating to the Packing of Pistons for Hoists
or other Hydraulic Purposes.
I, JOHN ALEXANDER STEVEN of 12 Royal Crescent, Glasgow, Lanarkshire,
Engineer, do hereby declare the nature of my invention, and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement in writing that is to say :-
This invention has reference to and comprises a new or improved mode and
means of packing pistons for hoists, rams, or other hydraulic purposes, and which
will enable the pistons to work fluid tight without attention or repair for a much
longer period of time than heretofore.
And in order that my said invention, and the manner of performing or carrying
the same into effect or practice may be properly understood I have hereunto
appended an explanatory sheet of drawings in which
Figure 1 represents a sectional elevation, and Figure 2 a plan view of a piston
fitted within an hydraulic cylinder, and constructed with elastic packing in
accordance with my improvements.
Referring to the drawings:-
As applied to the piston A of an hydraulic hoist, where the pressure water acts
downwards from above the piston to raise the load, the improvements consist in
fitting an annular ring a of vulcanized india-rubber or other elastic material on the

page_text: inside surface of the usual cotton or hemp packing material b pressing against the
hydraulic cylinder B. This india-rubber, a is formed of a doubled-up or Bwan-
bill shape turned inwards at its lower end a' and has a small annular india-rubber
ring a' inserted and pressed between the two duplex parts a a'. And another india-
rubber or elastic ring is fitted to act near the upper part of the main ring a to
freely move and press between its inner surface and the metallic part A' of the
piston A in which it is embedded in the slot A². A narrow water channel way or
duct c leads from the top of the piston A with branches c¹ ccc for the pressure
water to act on the inner surface of the last mentioned rubber ring ', and in the
annular space formed between the inner surface of the main rubber ring a and
the inner metallic part A¹ of the piston A so as to press on the elastic medium,
and through it retain the hemp or cotton packing material always as a substantial
fluid tight joint between the piston A. A¹ and cylinder B.
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: :-
First. In pistons for hoists or other hydraulic purposes, the fitting and use of an
annular ring a a' of india-rubber or other elastic material between the cotton or
fibrous packing next the cylinder, and the metal part of piston, substantially as
herein described in reference to and shown in the accompanying drawings.
Second. In pistons for hoists or other hydraulic purposes, the combination, and
use of aunular rings of india-rubber or other elastic material between the cotton or
fibrous packing, and the metal part of piston, and having channels communicating
with the upper side of piston for the water pressure to act on the elastic rings,
substantially as herein described in reference to, and shown in the accompanying
drawings.
Dated 11th day of February 1902
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.