Required to Support a Tensile Strain.
Year: 1886

page_text: Required to Support a Tensile Strain.
I, ROBERT WOTHERSPOON, 6 Burn Terrace, Hartlepool, in the County of Durham,
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 has for its object a spring safety buffer, that when linked in the
line of a chain rope or other tension device will deaden or buffer sudden strains,
and yet the spring of which cannot be injured by any strain which the line is
qualified itself to sustain.
This is effected by causing two or more parts of the line or its equivalent, each
to end in a plate past the plate of the other line, and by placing a spring in com-
pression between the two plates. 2nd by causing the lines or equivalents of those
lines, or one of them to act as a guide or guides for the spring. 3rd preventing too
great compression on the spring by means of a safety stop or strut.
There are numerous variations in detail for doing this, the drawings show two.
In Figures 2 and 3 which are longitudinal sections, Figure 1 being a transverse
section on line X,X, Figure 2, referring more especially to Figure 2, A is a cylinder
attached to and forming a part of line B by means of eye bolt C passing through
end D, and fixed by nut E. F other end of cylinder fixed to flange thereof by
screws G. It could however be screwed into A or otherwise fixed thereto. I eye-
bolt forming part of line H passing through end F of cylinder A, and attached to
piston J by nut K, L spring loosely fitting inside the cylinder A and abutting
against end F, terminal of line B on the one hand, and against piston J, terminal of
line H on the other end. M short piece of tubing which can be united or cast in
one with piston J or head F, or be quite loose as shown, this short piece is to limit
the strain on the spring, as, if the spring be sufficiently compressed for the piston
and end F to both come in contact with tube M, M takes the excess of strain. In
place of this tube an annular stop on the cylinder coming against the piston, or a
collar on the piston rod can be used, but this tubular arrangement is lighter,
stronger and more convenient than any other. If the piston be air-tight or nearly
so, besides the spring we have the compression of the air on one side, and the
tension on the other to assist the spring.

page_text: It is obvious also that in place of the cylinder, a series of two or more bolts or
bars uniting the two discs corresponding to the cylinder heads, and placed either
inside or outside the spring, will do as well. Also that the cylinder head D simply
forms a part of the tension line B, and can be dispensed with, or other form of con-
nection between the cylinder or its equivalent, and the eyebolt can be substituted.
Further that instead of single bolt I two or more bolts could be used similar in fact
to the bolts, that could as above described be substituted for the cylinder-in which
case the two ends would be alike and there would be a spring between two discs
with two or more bolts from each disc, passing inside or outside the spring, and
through or by the sides of the other disc, with a tubular strat in the centre, as set
forth in Figure 3. There is a great advantage in making the strut M tubular, as
this form is stronger for compressive strains for a given area of cross section than
any other; it distributes the strain over a wider area of the discs, and is a special
feature of my invention.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed, I declare that what
I claim is:
1st. The combination of a spring cushioning device, and an air cushioning device
in the same tension, spring buffer, substantially as and for the purposes specified.
2nd. The spring buffers constructed and arranged as a whole, substantially as
illustrated in the drawings, Figures 2 and 3.
3rd. The tubular strut M in combination with a cushioning apparatus such as
set forth in the drawings.
4th. The combination of a tubular strut (M) to prevent too great strain coming on
the spring with two discs each having two or more bolts or bars approximately
parallel with each other, passing through, or to the side of the other disc, and
attached beyond said disc to a chain link or other piece exposed to tensile strains,
and a spring compressed between said discs, and surrounding said bars, substan-
tially as described, but not illustrated.