Improvements in the Method of Constructing and Locking Telescopic Joints, and in the Application of the same to Various Useful Purposes.
Year: 1890

page_text: Date of Application, 17th July, 1890-Accepted, 13th Sept., 1890
COMPLETE SPECIFICATION.
Improvements in the Method of Constructing and Locking Telescopic
Joints, and in the Application of the same to Various Useful
Purposes.
We, EDWARD CHARLES DAVIS, of Penrith House, 190 Peckham Rye, London S.E.
and THOMAS BALDWIN, of 20 Ivydale Road, Nunhead, London S.E. Engineer, do
hereby declare the nature of our said invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
Our invention relates to the construction and fitting of rods, tubes, billiard cues,
telescopes, music stands, and other articles, the lengths of which it, may be found
convenient to adjust by telescopic action.
In the application of our invention to two tubes, telescopically arranged, we fit
the inner end of the smaller tube with steadying and stopping collars; and we
form slits in the tube, so as to render the same resilient, and thereby steady its.
motion in the outer tube, in which it slides. The open end of the outer tube is
chamfered off to a thin edge, and formed with gripping teeth, which are capable
of being compressed by means of a coned ring, so constructed that a partial rotation
of the ring effects the compression of the gripping teeth, and thereby locks the inner
tube in position.
And in order that our said invention may be particularly described and ascertained,
reference is hereby made to the accompanying drawings, in which similar letters of
reference indicate corresponding parts.
'
Fig. 1 is a sectional elevation illustrating the application of our invention to the
large end of a telescopic billiard cue.
Fig. 2 is a sectional view of the coned ring, and
Fig. 3 is an external view of the same.
a is the inner sliding tube. & are collars formed upon or attached to the
inner tube. The split collar 6 expands slightly and acts as a steadying collar, and
the collar acts as a stopping collar, to prevent the accidental withdrawal of the
inner tube from the outer tube, a shoulder k being formed in the outer tube d
for that purpose.
c is one of four saw cuts, which render the end of the tube a
resilient. is the outer tube. The open end of this tube d is chamfered off to
a fine edge, and gripping teeth e e are formed therein, as shown in Fig. 1. Two
or more helical or inclined slots ff are also formed in the tube d, for receiving
sliding studs h. g is the coned ring fitted to the end of the outer tube d, so as
to be capable of partial rotation. The studs are fitted to the inside of the coned
ring g, as shown in Fig. 2; the studs sliding in the slots f.
From the foregoing description it will be understood that, by turning the coned
ring in the direction of a right-hand screw, the coned ring travels downwards;
and this motion causes the conical portion of the ring to compress the gripping
teeth e e.
The friction arising from this compression firmly locks the inner tube
in any required position. By turning the coned ring in the opposite direction,
the cone recedes from the gripping teeth e e, and thus removes the frictional contact
with the inner tube a. The inner tube may then be drawn outwards or pushed
inwards, as required, and again locked, as before described.
In adapting our invention to billiard cues, the tube a is extended to the usual
length by means of a light tapered rod of the usual form, fitted to its outer
end. But such billiard cues possess the additional advantage of being adjustable
in length.
Our invention is applicable to many articles which require telescopic and locking
action, and to any number of joints in the same article.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
:-
1. In the construction of telescopic joints, the combination of locking mechanism,
consisting of a coned collar g, fitted with studs h, working in helical or inclined
slots f, for compressing gripping teeth e e, and thereby locking the tube or rod a
in any required position, substantially as hereinbefore described and illustrated by
the drawings.
2. The improvements in the method of constructing and locking telescopic joints,
and in the application of the same to various useful purposes, substantially as herein-
before described and illustrated by the drawings.
GEO. DOWNING,
8, Quality Court, London, W.C., Agent for Applicants.
GEO.
DOWNING,
8, Quality Court, London, W.C., Agent for Applicants.