U.S. patent number 3,904,199 [Application Number 05/387,922] was granted by the patent office on 1975-09-09 for sports racket stroking trainer.
Invention is credited to Paul James Burchett.
United States Patent |
3,904,199 |
Burchett |
September 9, 1975 |
Sports racket stroking trainer
Abstract
A sports stroke training device having a post for mounting
vertically on a vertical surface. The post is provided with a
longitudinal groove for adjustably retaining a pivot shaft. An
elongated bar is mounted intermediate its ends on the pivot shaft
for pivotal movement thereon. The bar is provided at each of its
ends with a flexible guide member which extends perpendicular from
the bar in a direction from the post. A correct racket stroke is
made when both guide members are hit during the stroke along the
longitudinal centerline of the bar.
Inventors: |
Burchett; Paul James (Corona
del Mar, CA) |
Family
ID: |
23531863 |
Appl.
No.: |
05/387,922 |
Filed: |
August 13, 1973 |
Current U.S.
Class: |
473/461 |
Current CPC
Class: |
A63B
69/38 (20130101) |
Current International
Class: |
A63B
69/38 (20060101); A63B 069/40 () |
Field of
Search: |
;273/26R,29A,191R,191A,192,186R,186A,186B,186C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pinkham; Richard C.
Assistant Examiner: Brown; T.
Claims
I claim:
1. A sports racket stroke training device adapted for attachment to
a vertical support surface comprising:
a post, said post having attachment means for attaching said post
substantially vertical on said support surface, said post also
having a longitudinally extending groove therein;
a pivot shaft, said pivot shaft being received in said groove of
said post, means for releasably holding said pivot shaft in said
groove for selectively adjusting said pivot shaft at an infinite
number of positions along said groove;
An elongated bar, said bar having means intermediate its ends for
connecting said bar to said pivot shaft, said bar therefore being
angularly pivotal and slidably adjustable on said post by said
pivot shaft;
a pair of substantially elongated flexible guide members, said bar
having a guide member attached substantially perpendicular to each
of its ends, said guide members extending parallel to said pivot
shaft and from a common side of said bar such that a racket must be
swung past both guide members when stroked substantially along the
longitudinal center line of said bar.
2. The sports stroke training device as defined in claim 1, in
which said bar contains indicia adjacent said pivotal shaft, said
indicia providing visual reference for angular settings of
45.degree., 80.degree. and 100.degree. for said bar relative to
said post.
3. The sports stroke training device as defined in claim 1, wherein
said guide members are substantially straight such that both guide
members are hit by a racket when a correct racket stroke is
made.
4. The sports stroke training device as defined in claim 1 wherein
said guide members are shaped as a circular hoop having a section
removed therefrom to define an opening, said opening being slightly
larger than a racket head, said guide members being attached to
said bar at a point substantially diametrically opposite said
removed section opening of said hoop such that when a correct
racket stroke is made the head of a racket will pass through the
opening of the hoop without touching and the handle will pass
through said removed section opening of said hoop without
touching.
5. The sports stroke training device as defined in claim 1, wherein
a target member is attached intermediate the ends of said bar such
that said target will be hit by a racket head when said racket is
stroked along the longitudinal center line of said bar.
6. The sports stroke training device as defined in claim 5 wherein
said target is a ball, said ball being held on said bar by an
elongated shaft which is perpendicularly attached to said bar.
7. The sports stroke training device as defined in claim 6 wherein
said ball holding shaft is flexible such that it will bend when
said ball is hit.
Description
BACKGROUND OF THE INVENTION
This invention relates to training devices for the stroking of
sports rackets. This general term is intended to mean tennis,
squash, and badminton rackets and the like.
Except for overhead smashes, the main strokes used in tennis and
squash can be divided into two categories. Horizontal strokes are
within about 10.degree. of being parallel with the ground, and lobs
are up approximately 45.degree. from the ground.
Within the applicant's experience, there has heretofore been no way
to indicate the angle of a racket stroke. Yet the development of a
consistent and proper stroking path is a major factor in
controlling the flight path of the ball.
The purpose of a lob is to force an opponent to retreat from a net
position by hitting the ball above his reach. There is an
interesting law of physics that states that the trajectory of a
ball, hit with the same force, will travel furthest horizontally if
hit at a 45.degree. angle. The distance can best be controlled if
the 45.degree. angle is used consistently and the hitting force
varied.
Horizontal strokes can vary slightly in order to add "top spin" or
"back spin." "Top spin" results from the racket travelling upward
at about 10.degree. from the horizontal. This causes the ball to
have a flat bounce when it lands. "Back spin" is created when the
racket is moving downward at about 10.degree., and causes the ball
to bounce more nearly vertical. In these strokes, as well as the
flat power strokes between, it is important to follow the same path
for a length of nearly two feet.
A "volley" is a horizontal stroke applied to a ball while traveling
nearly flat, usually in the area of the net. In this case, the
racket should be pushed with the shoulder and body along a straight
line rather than in an arc.
SUMMARY OF THE INVENTION
My invention allows the stroking of a sports racket to be made more
consistent, more accurate and better related to follow-thru and
foot position.
A principal object of the invention is to provide a device that
indicates the angle of a racket stroke relative to the ground.
A further object is to allow an angle indicator to be adjustable in
angle as well as in height.
An additional object is to provide for placement of the user's feet
in a specific position relative to the angle indicator.
A still further object is to allow use of the device by left or
right handed players.
In the simplest and preferred embodiment, my invention consists of
a vertically grooved post, adapted for attachment to a vertical
surface such as a wire fence, and a pivoting bar with a guide
member extending horizontally from each end. The bar is adjustable
angularly about the pivot, and the pivot slides in the groove of
the post for height adjustment. Indicia on the bar adjacent to the
pivot are aligned with the post to provide visual reference for the
angular settings.
The guide members are about 22 inches apart and extend about 10
inches from the bar. A compliant plastic tube such as polyvinyl
chloride is used for each guide member.
In use, the bar pivot is located at about the height of the
player's belt. Two chalk lines are drawn on the ground in line with
the two plactic tubes. For ground strokes and lobs, the outside of
the forward foot is placed on the front line. For volleys, the
fronts of both feet are placed on the back line. In both cases, the
imaginary ball is located at a point 8 inches forward of the rear
tube. For backhand strokes and left-handed forehand strokes, the
pivoting bar is reversed. The same chalk lines are still usable,
since the bar pivot is located centrally between the two guide
members.
Stroking of the racket is done in line with the pivoting bar. Both
guide members must be hit by the racket head for the stroking angle
to be correct. The bar is adjusted in the 45.degree. up position
for lobs, and between 10.degree. up and 10.degree. down for various
other ground strokes and volleys.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a persepctive view of the preferred embodiment in
operating position for a right-handed backhand lob.
FIG. 2 is a sectional view taken along lines 2 -- 2 in FIG. 1,
showing the assembly clamped to a fence.
FIG. 3 is a perspective view of an alternate embodiment in
operating position for a right-handed forehand ground stroke.
FIG. 4 is a sectional view taken along lines 4 -- 4 in FIG. 3,
showing a practice ball mounted to the target member.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, front guide member 1 and rear guide member 2
are attached near the ends of pivoting bar 3, which is rotatable
about pivot shaft 4 relative to vertical post 5. Post 5 contains
undercut groove 6 to retain enlarged end portion 7 of shaft 4,
shown here as a wingnut on a screw. Mounting screws 8 and 9 fasten
thru fence 10 into plate 11 on the opposite side. Indicia 12 are
aligned with post 5 to provide visual reference for the angular
settings used.
An alternate embodiment is shown in FIG. 3, with front guide member
13 and rear guide member 14 being attached to the ends of bar 15 by
screws 24. Bar 15 is rotatably connected to post 16 by bolt 17 and
held by wingnut 18. The head of bolt 17 is retained within undercut
groove 19 which allows sliding of bar 15 in a vertical direction.
Compliant target member 20, held by screw 34, extends horizontally
from bar 15 intermediate guide members 13 and 14, and can have
practice ball 21 attached to the end of member 20 by screw 22. If
the racket approaches in the direction of arrow A, target member 20
will be between bolt 17 and rear guide member 14. Indicia 23 are
selectively aligned with groove 19 in post 16 for visual reference
to the angular settings chosen. Post 16 is attached at each end to
fence 25 by bolts 26 in slots 27, with washers 28 and nuts 29 being
applied from the opposite side of fence 25.
In the alternate embodiment of FIG. 3, alignment of the compliant
portions of guide members 13 and 14 is used differently to indicate
the desired path for the swinging of a sports racket. In the
preferred embodiment, both guide members are hit by the racket
head. In the embodiment of FIG. 3, target member 20 is the only
part contacted by the racket head. The correct swing has been
achieved when compliant portions 30 and 31 of front guide member 13
and compliant portions 32 and 33 of rear guide member 14 have all
been cleared. To allow this to happen, portions 30 and 31 are
separated vertically by a distance greater than the width of a
sports racket head. Portions 32 and 33 are similarly separated.
This invention is not to be limited by the embodiments shown and
described, which are given by way of example and not of
limitation.
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