CA1138486A

CA1138486A - Racket sport training device

Info

Publication number: CA1138486A
Application number: CA000329917A
Authority: CA
Inventors: Roger A. Hedge
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-06-16
Filing date: 1979-06-15
Publication date: 1982-12-28
Also published as: GB2038645B; WO1980000062A1; JPS55500721A; GB2038645A

Abstract

RACKET SPORT TRAINING DEVICE
ABSTRACT
This Invention relates generally to training devices which make it easier for a player to learn correct strokes in any of a multiplicity of racket sports. Racket games such as badminton, tennis, racket ball, and squash are enjoying unparalleled popularity among those persons fond of the active participant sports. Every year hundreds of thousands of people take up a racket for the first time to play one of these health and invigorating games. Among these multitudes, there are many people who wish to attain levels of achievement in the sport greater than that of a casual player. Unfortunately, such training usually mandates that the player find a top notch instructor, of whom there are all too few. The present in-vention overcomes this problem by providing a racket sport training device (10) for a player to use against a flat surface (42) (such as a wall), and including an elongated shaft (12), a handle (14) attached to one end of the shaft, and a ball (16) or other rotatable member (16') attached proximate to the other end of the shaft. The rotatable member (16, 16') is adapted to contact and follow the flat surface (42) in order to guide a racket sport player through the correct arm and wrist motion for the racket ball sport being practiced.

Description

~13~34~6 ~ACI51~ SPORT TI~AINI~ DEVICF.
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TE'C~INICAI, :Ei'IELD
This lnvent-10rl relates genera]l~ to sports equipment and more particularly to trainlng devices which make it ea~Le~ for a player to learn correct strokes in any of a multipllci-iy o~` racket sports.
~ACKGRO-UND OFI I~IE PRIOR ART
Racket games such as badminton, tennis, racket ball, and squas'l are enJoying unparallel popularity 10 among those persons fond o~ the active partlcipant sports Every year hundreds of thousands of people take up a racket for the first time to plaJ one of these healthful and lnvigorating games. Among these multi-tudes, there are many people who wish to attain levels 15 of achievement in the sport greater than that of a casual player. ~or these people, proper and adequate training in the fundamental strokes is a necessity.
Unfortunately, such training usually mandates that the player find a top notch instructor, o~ whom 20 there are all too few. Even after a good instructor is found5 training in even the fundamentals of a racket sport game is an extremely time consuming process and thus often a very costly one.
While instructional methods varyf all methods

2~ seem to have a few common features. Typically, after the lnstructor discusses the particular stroke to be worked upon (for example, the forehand stroke or the overhead smash) the player is asked to take his or her racket in hand and swing it about as if hitting an 30 imaginary ball or birdie. A fundamental problem with this method of instruction is that the player has no reliable way of knowing as to whether his stroke is really correct or not. Especially in larger classes, a player may practlce a stroke incorrectly for an entire 35 class session. If the student continues to practice the stroke incorrectly~ his incorrect technique may become so ingrained that it could take years to un-learn.
Another instructional method somet~mes used in small classes is called the "manual guidance method~

An instructor utili7ing this method would grasp the student hy ~he T~!rist or arm and guide ~he student through a correct ~troke. ~lle thls method of in-structlon may be helpful in giving the student an in-tellectual conceptualization of what a correct strokeshould be, lt is an extremely ineffic-lent way of train-ing the student to use his own musculature to swing the racket through a stroke since the instructor is supply-ing all of tl~e mot~ve force. Learning a stroke by the 10 manual guidance ~cthod is likened to a piano student learning to play the piano by having his teacher press his fingers on the correct keys instead of having the studen~ learn to use his own brain and muscles to produce the correct notes.
~at is sorely needed in the field of racket sport training devices is a device which, under the action of the students own musculature, guides the students arm and wrist through a correct stroke time-after-time. Furthermore, such a device should be usable 20 by a player without need for instructional supervision.
To my knowledge, no such device exists in the prior art.
RIEF SUMMARY OF THE INVENTION
It is a major ob~ective of ~J invention to 25 provide a racket sport training device which, without fail, guides a student through a correct racket ball sport stroke. Furthermore J it is my objective to pro-vlde the above-mentioned object with a device that requires little supervision from instructor.
Yet a further objective of my lnvention is to provide a racket sport training device which can provide an indication of the efficiency and correctness of the stroke by the means of a suitable feedback or readout device.
Eriefly, my invention comprises an elongated shaft having a first and a second end and defining an axis therethrough, a handle attached to a first end of the shaft5 a surface following means (such as a ballg disk or wheel) defining a second axis and for contacting ,:

' :
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11384~6 , and f'ollowing a f'la-t surf'ace, ancl means l'or attaching the surface ~ollowing mearls prox-lmate a second end o~
the shaft so that ~he ax-ls ~ the shart and the ~xis of the surf'ace following means are coaxial.
~ materia] advantage of my lnvention is that, after assimilating a few slmple instructions5 a player can use my device to quickly ancl easily learn a correct racket sport strol{e with practically no supervision from an inst;ructor. Furthermore,~ when my device is provided wit:- a monitoring apparatus~ the efficiency and correctness of each of the players strokes can be displayed t~ provide a very instructive feedback mechan-ism.
These and other obJects and advantages of my present invention will no doubt become apparent to those skilled in the art after having read the follow-ing detailed description as accompanied by the several figures of the drawing.
BRIEF DESCRIPTION OF THE DRAWIN~S
-Fig. 1 is a partially broken perspective view of a racket sport training device in accordance with my present invention;
Fig. 2 is a cross-sectional view taken along line 2-2 of Fig. l;
Fig. 3 is a pictorial representation of a player using the device shown in Fig. l;
Fig. 4 is a pictorial representation of a player using the device shown in Fig. 1 with an optional or accessory portable surface means in accordance with my inventiong Fig. 5 illustrates a first alternate embodi-ment for a racket sport training device in accordance with my present inventionS
Fig. 5 illustrates a second alternate embodi-ment of my racket sport training device;
Fig. 7 illustrates a third alternate embodi-ment of my racket sport training deviceg and Fig. ~ illustrates yet another alternate embodiment for a racket sport training device in 113~4~6 i~ , accordance with my present invention.
DET~ILED DESCRIPTION OF ~IE INVENTION
-In this disclosure my racket sport training device is sho~n and described in a configuration which makes it very suitable for the training of badminton strokes. It should he clearly understood, however, that with suitable and minor modifications my device can be used to teach proper wrist and arm motions for strokes associated with other racket sports suc'n as 10 squash and racket,ball. For example, by shortenlng the shaft and adding a little weight to the head of the device shown in Fig. 1 i~ could be used to train a player in the proper method of swinging a racketball racket.
In Fig. 1 and Fig. 2, my racket sport training device 10 may be seen to include an elongated shaft means such as a shaft 12, a handle means such as a handle 14 and a surface following means such as a "wiffle" type ball 16. Shaft 12, in this embodiment, 20 is a round bar which is preferably constructed from a strong yet lightweight material such as aluminum. The visible length of the shaft is approximately 12 inches long when my device is adapted for teaching badminton strokes. When adapted for racketball, the exposed 25 shaft length is preferably slightly shorter than 12 inches and when adapted for squash, the exposed shaft length is preferably slightly longer than 12 inches.
Shaft 12 could also be of a hollow or tubular construc-tion to minimize the weight of my device.
Handle 14 is typically an elongated member having eight side surfaces, and is usually permanently attached to one end of shaft 12 as shown. The handle has a wide, flat pair of opposing surfaces 18 which would normally be parallel to the face of a racket, and 35 a slightly narrower pair of flat opposing surfaces 20 `!
which would normally be perpendicular to the face of a racket. Beveled surfaces 22 connects surfaces 18 and 20 to provide a comfortable, slightly rounded surface for the handle. Usually a handle tape 24 is wrapped .

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~384~

around the handle so as to provide a sure grip f~r a user's hand.
Wiffle type ball 16 is provided with an aper-ture means, such as that created by holes 26 and 28, for receiving the end portion of shaft 12. Holes 26 and 28 are aligned along a major axis of ball 16, which is coaxlal with the axis "Al of shaft 12.
A sleeve means such as sleeve 30 is attached around shaft 12 to prevent ball 16 from sliding down 10 the shaft. Sleeve 30 is typically a short piece of cylindrical tubing that is adhesively or otherwise attached coaxially about the shaft. It is also possible to form a sleeve 30 by wrapping a piece of friction tape around the shaft.
A cap 32, which in this preferred embodiment is a standard axle cap, is press fit over the free end of shaft 12 to prevent ball 16 from sliding off the end of the shaft. ~all 16 is thus loosely held between members 30 and 32 so that it may freely spin upon shaft 20 12. If imparted with a sufficient rotational force, the ball will spin quite freely for a number of seconds.
In Fig. 3, a player 34 is shown using my device ~ against a wall 36 in order to learn a correct stroke. In this stroke, the p]ayer 25 grasps the handle of my device so that the V-shaped fold of flesh between his or her thumb or forefinger is aligned with one of surfaces 20, and the player's arm is held out from the body so that it is substan-tlally parallel to the floor.
The player begins his stroke with my training device ln the position labeled "P", which corresponds to the preparatory position of a badminton swing. The wrist is cocked and the arm is twisted so that the palm of the hand faces upwardly and slightly towards wall 35 34. The player then strokes forwardly with my device, as indicated by arrow 38, while at all times keeping ball 16 rolling along the wall. When ball 16 is in position 40, the arm and wrist of player 34 is in the correct position to hit the imaginary shuttle 42 as 1~38486 shown This is known as the contact point and is de-noted by the le-cter "C . The player then continues to follow through wlth the strokeS still rolling ball 16 along wall 36, until the racket sport trainlng device is in a substantially vertical position. This is known as the follow through position and is denoted by the letter "F". In the follow through position, ball 16 should be separated from the wall by a slight fraction of an inch, the wrist should be cocked, and the palm 10 should face outwardly from the wall. If the stroke was an effective and powerful one, ball 1~ would be whirling vigorously to indicate good acceleration and smooth stroking. If ball 16 is only rotating feebly5 it is an indication that perhaps the stroke was per-15 formed in a jerking manner, that it was not performedalong that flat vertical surface of wall 36, or that the acceleration of the stroke was slow.
The back-hand stroke (not illustrated) is very similar to the forehand stroke. In this stroke the 20 player faces in khe opposite direction along wall 36 in a starting pos-ltion with his wrist cocked~ and his palm facing outwardly from the wall. The stroke is then performed in a similar manner to that of the forehand stroke e~cept that the final or follow through position 25 is with his wrist cocked and palm towards the wall.
The theory of operation for my invention is believed to be as follows. For a truly efficient power stroke, it is necessary that the force exerted by a player's racket upon a shuttle is primarily in 30 the direction of the desired shuttle flight. Any motion imparted to the shuttle that is not in its desired direction of flight will have been expended to no useful purpose (this of course does not include such esoteric techniques as "drop shotsi'S etc.). In part, 35 the purpose of my device is to force a player to move his racket head along the plane of the shuttle's in-tended flight. My device further insures that the correct wrist ancl arm action is used if only the racket started and stopped in the correct preparatory and `:

¢486 ~ollow thro~C~I positions. ConsequentlyJ a player uses his own musculature to perform near-perfect badminton stro~es from the very flrst when using my training device. It has been found that beginning players uslng my device can learn a badminton stroke in a few short hoursJ something which otherwise might take many years of practice.
Referring now to Fig. 4, an apparatus ~2 is shown which allows my racket sport training device 10 10 to be used to teach overhead strokes. Learning over-head strokes against a wall, such as wall 36, is im-possible since it would necessitate that the player stand within the plane of the wall. My device 10 has been used successfully to teach the overhead stroke by having a player stand in a doorway and use the trestle thereabove for the flatJ vertical surface. However, a suitable doorway is not always available and for this reasonJ apparatus 42 is preferable.
Apparatus 42 includes a base portion 44 which is disposed on a flat, horizontal surface such as a floor, a pair of posts 46 and 48 and a backboard 50 which is provided with a pair of vertical bores 52 and 54 into which respective ends of shaft 46 and 48 are inserted. A pair of ad~ustable sleeve members 56 and 58 are provided to prevent the backboard from sliding down the posts. By ad~usting the height of the sleeves ! above the baseJ the height of the backboard can be adjusted to accommodate players of various heights.
The backboard 50 may also be dropped to the level of a player's midbody to provide a flat, vertlcal surface on which to practice underhand strokes~
In use, a player wishing to learn overhead strokes stands under t~ne backboard 50 and places ball 16 of my device 10 against a rear surface thereof as 35 shown. The players start in preparator~J position "P"
with his wrist cocked and palm facing towards back-board 50J swings through an imaginary birdie at contact point "C" and follows through to follow through to a position "P' where his wrist is extended and radially B

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flexed, h-ls forearm pro,-lated and his upper arm medially rotated.
Of course; al~ a~paratus lor providing a flat, planar surface on which to pract;ice overhead strokes need not be portable as shown. For lnstance, a back-board could be mounted parallel to and slightly spaced ~rom a wall b~J means of suitable brackets.
Referring now to ~ig. 5, an alternate embodi-ment of my invention includes a transducer means such 10 as a generator 60 which has a housing portion 62 and a rotary sha~t 6~ Housing 62 ls attached coaxially to the free end of sha~t 12 and shaft 64 is attached to ball 16 by a fastener such as bolt 66. As ball 16 is spun during a practice stroke5 sha~t 64 ls imparted 15 with a spin This causes an electrical signal to be developed between a pair of lines 68 which can be de-tected by a monitoring apparatus 70 having one or more of the plurality of output devices shown. For in-stance, a digital output 72 could display the total 20 number of revolutions performed by ball 16, its maximum acceleration, or any other pertinent and helpful data.
A strip recorder 74 could, for example, record the rotational velocit~J of ball 16 from the preparatory stage to the ~ollow through stage an~ beyond. An audio output device such as speaker 76 could produce a tone proportional to the rotational speed of the ball and thus act as a valuable and continuous feedback mechanism for the player Similarly, a light emitting device 77 or a meter 78 could provide a visual display o~ the voltage leveI~developed between line 68 and thus in-dicate how fast ball 16 is spinning. As mentioned earlier, the speed of rotation of the ball is a good indication of the correctness of the stroke. In one embodiment of my invention, a lightbulb ~s disposed within ball 16 so that the ball is illuminated from within to provide the player with immediate visual feedback as to the efficiency of his strokes.
Another means for monitoring the efficiency of the players stroke is shown in Fig. 6 to include a .

~138~6 revolution meter ~ avir-lg a housing portion 82 and a shaft 8L~. Ilou~nG ~ ic; attached coa~.-lally to the free end of shaft ~2 and shaf't 8l~ ls attached to a solid ball 12' hy means of a stud 86. r~eter 80 has a d-lgital readout 88 for iLld1cating the number of revolutions that ball 12' undergoes. Note that, in this embodiment, ball 12' is a solld, ~pherlcally-shaped member having an inner core 90 and an outer covering 92. This solid ball tends to rotate longer than the hollow one due to 10 a fl~/wheel-like action. Outer covering 92 is prefer-ably a material of a high frictional coefficient (such as rubber) so that it may more positively engage one of the flat surfaces discussed earlier.
In Fig. 7J several means for adJusting the 15 "feel" of my racket sport training device are illus-trated. In this embodiment, a handle 14' is provided with a bore 94 into which a thumb screw 96 may be screwed. The end of shaft 12' is disposed within shaft 94 and is held therein by firmly tightening thumb 20 screw 96. This embodiment further includes a weight 98 provided with an axial bore 100 and a thumb screw 102 which may be screwed into that bore. The weight can be disposed at various positions ~.long shaft 12' and can be immobilized by tightening down thumb screw 2~ 102. Thus, the exposed length of shaft 12'~ay be adjusted by sliding lts end in and out of bore 94 and the weight distribution of m~ device may be adjusted by varying the position of the weight along the shaft.
With these two ad~ustments~ a single device 30 in accordance with my invention can be used to train players for many different racket sports. For instance, a short shaft and heavy head would be good for training racket ball strokes and a long shaft and light head would be good for training badminton st:^okes.

3~ In ~ig. 8, another embodiment for my device includes a disk-like surface following means 104 that is nonrotatably attached to an end port~on of shaft 12' by a pair of nuts 106 and 108. Disk 104 of this embodiment does not rotate with respect to the shaft i ~V~J~

but it could do so if lt were loosely attached to the shaft rather tha.! being clamped between the bolts. The disk of this embodiment should be made out of a material having a 101~J coerficient of friction, such as a polished stainless steel or a very hard plastic, so that there is very little drag as outer surrace llO follows a wall or oth~r flat surface.
The embodiment Or ~ig. 8 illustrates the very important fact that the shape of the surface following 10 means is not cr-ltical as long as it is configured so as to be radially symmetrical about the axis of the shaft means.
Although this invention has been described in the light of a few preferred embodlments, it is con-15 templated that various modiflcations and permutationsthereof will become apparent to those skilled in the art after having read the preceding detailed descrip-tion.
~or example, a rotary wheel could be attached 20 to shaft 12 to perform the same surface following task as the previously described balls or disk. Also, many other means for monitoring the efficiency of the strokes are possible, such as forming whistle prodv.cing apertures around the surface of a ball in order to 25 produce a whistling sound having a frequency dependent upon the speed of rotatlon of the ball. Furthermore, the surface that my device is used against may be curved, non-vertical or many other configurations.
It is therefore intended that the following 30 appended claims be interpreted as covering all such modifications and permutations as fall within the true spirit and scope of my invention.

Claims

-11-A racket sport training device for a racket sport player to use against a surface and comprising:
an elongated shaft means having a first end and a second end and defining a first axis; a handle means having a first and a second end; first means for fastening said handle means to said first end of said elongated shaft means; surface following means for contacting and following said surface; and second means for attaching said surface following means proximate to said second end of said shaft means, whereby a person who grasps said handle, disposes said surface following means against said surface and swings through an imag-inary shuttle or ball is guided through a correct racket stroke.
2. The racket sport training device as claimed in Claim 1, wherein said surface following means in-cludes a member that is symmetrical about a second axis which is coaxial with said first axis.
3. The racket sport training device as claimed in Claim 2, wherein said member is provided with an aperture means receptive to said second end portion of said shaft means.
4. The racket sport training device as claimed in Claim 3, wherein said member is spherically shaped and said second axis is a major axis of said spheri-cally shaped member.
5. The racket sport training device as claimed in Claim 4, wherein said spherically shaped member is substantially solid and said aperture means comprises a bore formed coaxially with said second axis.
6. The racket sport training device as claimed in Claim 4, wherein said spherically shaped member is hollowed and said aperture means comprises a pair of opposing holes formed through the surface of said member along the line of said second axis.
7. The racket sport training device as claimed in Claim 5, or 6 wherein a portion of said shaft means proximate said second end is disposed completely through said aperture means of said member, and wherein said second means comprises; a sleeve means attached co-axially about; said shaft means between said member and first end; and a cap means attached over said second end of said shaft means; whereby said member is free to rotate about said shaft means and is retained between said sleeve means and said cap means.
8. The racket sport training device as claimed in Claim 3, wherein said member is disk shaped.
9. The racket sport training device as claimed in Claim 1, wherein said handle means includes an elongated bore extending from a first end thereof at least partially towards said second end thereof.
10. The racket, sport training device as claimed in Claim 9, wherein said first means includes means for permanently attaching said first end portion of said shaft within said elongated bore.
11. The racket sport training device as claimed in Claim 9, wherein said first means includes a bolt means disposed through a threaded bolt hole formed through said handle means and opening on said bore, whereby disposing a portion of said shaft means proxi-mate said first end within said bore and tightening said bolt means adjustably fastens said handle means to said shaft means.
12. The racket sport training device as claimed in Claim 1, further comprising a weight adjustably attached to said shaft means, whereby the balance of said training aide may be varied by disposing said weight along various positions along said shaft means.
13. The racket sport training device as claimed in Claim 2, further comprising means for moni-toring the efficiency of said stroke.
14. The racket sport training device as claimed in Claim 13, wherein said means for monitoring includes; a revolution meter including a second shaft means and a housing having a digital display for in-dicating the number of revolutions of said second shaft means; third means attaching said housing to a second end of said first shaft means; and fourth means attach-ing said second shaft means to said member; whereby as said member follows said flat, vertical surface, said second shaft is caused to spin for a number of revolu-tions determined by the efficiency of said stroke.
15. A racket sport training device as claimed in Claim 14, wherein said revolution meter includes: a transducer means in said housing, whereby said trans-ducer means converts rotary motion of said second shaft means relative to said housing into an electrical signal; and an output means responsive to said elec-trical signal and operative to produce on said display an indication of the efficiency of said stroke.
16. A racket sport training device as claimed in Claim 15, wherein said transducer means includes a generator.
17. A racket sport training device as claimed in Claim 16 wherein said output means includes a light emitting device operative to emit light having an intensity functionally related to the voltage level of said electrical signal.
18. A racket sport training system comprising:
a first member including, an elongated shaft means, a handle means attached proximate a first end of said shaft means, and a surface following means attached proximate a second end of said shaft means; and surface forming means provided with at least one flat, vertical surface, whereby a person who grasps said handle, dis-poses said surface following means against said flat, vertical surface and swings through an imaginary birdie or ball, is guided through a correct racket stroke.
19. A racket sport training system as claimed in Claim 18, wherein said surface forming means includes;
a base portion disposed upon a flat, horizontal surface, post means rising substantially perpendicularly from said base portion, a backboard means provided with said flat, vertical surface, and means attaching said back-board means is positioned above said base means so that a player can dispose said surface following means against said flat, vertical surface to practice over-head and underhand strokes.