Year: 1887

page_text: I, WILLIAM EDWARD KAY, of Thornliebank, near Glasgow, in the County of
Renfrew, Chemist 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 :-
The improvements relate to the construction or manufacture of rackets, racquets, or
bats, employed in the game of lawn-tennis; and have for object the adjustment, or
variation of the weight of such rackets in one and the same instrument. In the
prosecution of the game of lawn-tennis, different players require, very often, rackets
of different weights; and it is common for a given player to purchase a racket of a
certain weight, which, after an amount of trial or practice therewith, he finds to be
unsuitable, or is desirous to alter the same. In rackets as commonly made, this is
impracticable, except by changing for another, which generally means the purchase of
a new bat. It has already been sought to remedy this defect by constructing rackets
with hollow handles in which rods of metal or other weights are inseried for the
purpose of increasing the weight of the instrument as required. But this method is
open to the objection that the "balance" of the racket is too much interfered with by.
altering the position of the centre of gravity.
In carrying out my improvements I so construct a differentially weighted racket
that the centre of gravity is not at all or very little disturbed, and thus the instrument
is constantly balanced at all the weights it is designed to carry.
To accomplish this and to effect my improvements. I ascertain the centre of gravity
of the racket, which is usually within the limits of the wedge, and, by preference, bore
a hole through the wood at or near that point. I then prepare a number of suitably
sized plates or discs of metal or other substance preferably circular in shape giving the
different weights it is desirable to arrange for.
By preference these discs are attached to the racket in pairs, one on one side thereof,
and one on the other, and one of them is provided with a shank tapped as a screw,
while the other is provided with a thicker shank which is bored and tapped for the
reception of the first named screw-shank, so that by screwing together, through the
hole in the racket, the same is clipped by the two discs, which may be screwed up to
any degree of tightness required, and if desirable provided with lock nuts. Any

page_text: number of different pairs of discs, giving all varieties of weights requisite, may be
prepared, and when it is desired to alter the weight of a racket, all that is necessary is
to remove the pair of discs already thereon, and to attach another pair of a different
size or weight, when, in consequence of the altered weight being-with the employment
of circular discs equal all round the centre of gravity, the "balance" is not interfered
with. Other forms than the circular however are nearly if not wholly as efficient in
practice; such as the oval, the ellipse, the oblong, and many fancy designs, and these
may be employed without departing from the peculiarity of my invention.
Likewise the method of attaching the discs or plates to the racket may be varied,
such as by means of simple screws, the discs or plates not being provided with shanks.
Also by a screw projection fixed on each side of the racket, upon which the discs or
plates may be screwed by means of tapped holes through their centres. Also by
ineans of grooves formed either in the racket or in secondary plates attached thereto,
in which grooves the discs or plates may be made to slide. And the discs or plates
may be attached to one side of the racket only, as a modification.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
The employment of movable discs or plates of any suitable form or size, which are
capable of being attached to, or detached from one or both sides of lawn-tennis rackets,
at or near the centre of gravity thereof, for the purpose of altering the weight of such
rackets without unduly interfering with the "balance" of the instruments, in manner
substantially as described.
1005
WILLIAM GADD, C.E.,
64, Barton Arcade, Manchester,
Agent.