Improvements in Lawn Tennis Poles.
Year: 1893

page_text: Date of Application, 17th May, 1893
Complete Specification Left, 26th Jan., 1894-Accepted, 17th Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in Lawn Tennis Poles.
I, EDWYN ANTHONY, of Newton House, Belmont Road, in the City of
Hereford, Barrister-at-Law do hereby declare the nature of this invention to be as
follows:-
Its object is to construct lawn tennis poles and to strain the net-cord in connection
therewith so that the former shall not require attachment to the ground. As
usually effected, the tension of the net-cord tends to produce rotary motion; and
this tendency is counteracted by guy ropes, or by fastening the tennis poles or their
frames to the ground, or by placing heavy weights upon the frames.
When constructed according to my invention, the only motion which can take
place is a horizontal one; and the friction between the ground (whether grass,
gravel, asphalte, or the like) and the frames suffices to prevent such motion.
I effect my object by the combination of two features, namely,
(a) By making the frame of each tennis pole project (in the direction of the
strain) to a length at least equal to the height of the pole. And
(b) By passing the net-cord over pullies or similar devices fixed to the tennis
poles; and straining it by weights or their equivalents which are attached to each
end of the cord, but which are detached and free from the tennis poles and their
frames. Equal weights may hang suspended from each end, or (which I prefer)
heavier weights at one end may rest on the ground and lighter weights be suspended
in the air at the other end. If the two fore-going conditions be fulfilled, it may be
readily shewn by simple and familiar statical principles that the only possible
motion (assuming the poles and frames to be rigid and the ground firm) is a
sliding one of the frame along the ground, and this motion the resistance of friction
will prevent.
Lin Tesh dow of Mo 1893
EDWYN ANTHONY.
COMPLETE SPECIFICATION.
Improvements in Lawn Tennis Poles.
I EDWYN ANTHONY of Newton House Belmont Road, Hereford in the County
of Hereford, Barrister-at-Law 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 chief object of my invention is to construct lawn tennis poles and to strain
the net-cord in connection therewith in such a manner that the former shall not
require attachment to the ground. As usually effected the tension of the net-cord
tends to produce rotary motion, and this tendency must be counteracted in some
way, as by guy ropes or by fastening the tennis poles or their frames to the ground,
or by placing heavy weights upon the frames &c.
When constructed in accordance with my invention the only motion which can
take place is a horizontal one; and the friction between the ground (whether grass
gravel, asphalte, or the like) and the frames suffices to prevent such motion.
Hence they require no attachment to the surface on which they rest.
In carrying out the end in view, I make use of the following principle or theorem
of statics. Let (Figure 1) the point or peg E be rigidly connected in any manner

page_text: with a straight and rigid rod A. B which rests on a fixed plane, CD being its line of
contact with the rod; let any two equal forces, say F and G, be applied at the
point E, the direction of one of them being perpendicular to and towards the plane,
and the direction of the other parallel to the rod A Band to the left as indicated
in the figure; and let H be the point in which the line of direction of the force
which is perpendicular to the plane meets the rod A B. Then, if the end B of the
rod be any distance to the right of the point H (or even coincide therewith), and if
also the length of the portion HA of the rod be not less than the length of the
straight line HE (.e. than the distance of the point E from the plane) the only
motion possible is a sliding one of the rod along the plane in the direction of its
length. Hence, if friction exist between the rod and plane no motion may take
place, and if the resistance of friction be sufficient to prevent motion in the case of
the two particular equal forces F, G, equilibrium will. in general be maintained
whatever two equal forces be substituted for them, since approximately the friction
varies as the pressure when the materials of the surfaces in contact remain the
same. It should be noticed that, if E be connected with the rod.A B by a straight.
rigid bar bisecting the angle FE G, then the rod A B may be as short as we
please, and yet there will be no tendency to any motion. except a sliding motion as
before.
This last statement is of course only true on the assumption that the bar and the
point or peg E are without weight, but its application-in-practice is shewn in Figs. 9
and 10.
I therefore effect my object by the combination of two features.namely
(a) By making the frame of each tennis pole project (in. the. direction of the
strain) to a distance at least equal to the height of the pole, and
() By passing the net cord over pulleys or similar devices fixed. to the tennis.
poles and straining it by weights or their equivalents attached to each end of the
cord, but which are detached and free from the tennis poles..and their frames.
Equal weights may hang suspended from each end, or (which. I. prefer) heavier
weights at one end may rest on the ground and lighter weights be suspended in the
air at the other end.
If the two foregoing conditions be fulfilled it may be..readily seen, from the
statical principle or theorem just explained that the only possible motion. (assuming
the poles and frames to be rigid and the ground firm) is a sliding one of the frame
along the ground, and this motion the resistance of friction will in most cases pre-
vent. When the surface on which the frame rests is unusually smooth, some slight
attachment of the frame thereto may be required, but with ground of the kind usual
for lawn tennis courts, both open and covered, the, resistance of friction alone
amply suffices to prevent motion. And in order that the said invention may be
fully understood reference may be had to the further accompanying drawings, Figs. 2
to 10, of which Fig. 2 is an elevation of the poles, net &c. when in position for
play Fig. 3 is the ground section of the frame of the tennis pole; Fig: 4 a section
of the pillar or pole itself; Fig. 5 shews an enlargement of the rod holding the
weights; Fig. 6 is a top section of a weight; Figs. 7 and 8 illustrate the poles &c.
somewhat differently arranged to what they are in Fig. 2; and Figs. 9 and 10 (eleva-
tion and section) illustrate a construction of pole according to the latter part of the
statical explanation in connection with Fig. 1. Similar letters of reference refer to
like parts in all the figures.
LXK W is the frame and N M the tennis pole or pillar, at the top of which
is fixed the pulley Rover which passes the net cord or wire. The pole fits into
the socket N of the frame, and is made quite fast by means of the screw thread and
nut T. The length K L may be greater but must not be less than the length KR,
i.e., than the height above the ground of the cord or wire at the point where it is.
at the top of the pulley R. If it be less, there will be a tendency to rotary motion..
In practice, however, if the frame be heavy, a few inches will not matter. U.is the
net, QRS the net cord or wire, P the rod which is attached to the cord or wire
for the purpose of holding the weights, and O, O are the weights themselves..... In

page_text: Fig. 2 they are shaped as shewn (for top section thereof see Fig. 6) in order that they
may fit round the poles, without necessarily touching them. In the same Figure (2)
the net is shewn broken off as the size of the paper does not permit of its whole
length being given in right proportion to the height of the tennis poles. The
part W X of the frame is to obviate any risk of the frame and pole swaying from
side to side. Figs. 7 and 8 shew, the frame and pole somewhat differently arranged to
what they are in Fig. 2, and they do not need further explanation. Figs. 9 and 10
illustrate a construction of pole made on the lines of the latter part of the statical
explanation. It may be useful in cases where there is no objection to a portion of
the pole going under ground, and extreme cheapness is desired. In this case the
pole has for frame a collar Y Z which goes round the bottom of the pole, the pole
being inclined to the plane of the collar at an angle of 45°. NJ (shewn by the
dotted lines) is a thin spade or other convenient shaped continuation of the pole.
ab is the ground line. The pole is fixed by driving the spade shaped continuation into
the ground at an angle of 45°, until the under surface of the collar Y Z comes into
contact with the ground. The pole will then be inclined to the ground at the same
angle (45°) and the strain caused by the weights will be in the direction of the pole
and can therefore as before only cause a sliding motion, if the ground be firm. And
as before, friction will be sufficient to prevent this, apart from the spade shaped
projection in the ground, the object of the latter being to stop the pole from falling
by its own weight. The chief use of the collar Y Z is to ensure the pole being fixed
at the right height and at the right angle. No pulley but a groove instead is shewn
for the net cord or wire to pass over.
Aside from the slight additional expense, a
pulley as shewn in the other figures is preferable to a groove.
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. The combination of a lawn tennis pole, fixed in a frame of which the length
(in the direction of the strain) is not less than the height above the ground of the
highest point of the net when in position for play, with a net cord or wire passing
over a pulley or similar device fixed to the tennis pole and strained by weights or
their equivalents which are detached and free from the tennis pole and its frame;
all substantially as described.
2. The combination of a lawn tennis pole fitted with collar and continuation for
fixing same in ground at an angle of 45°, with a net cord or wire passing over a
pulley or similar device fixed to the tennis pole and strained by weights or their
equivalents which are detached and free from the tennis pole; all substantially
as described.
Dated this 25th day of January 1894.
EDWYN ANTHONY.