CA1154474A - Molded racquet - Google Patents
Molded racquetInfo
- Publication number
- CA1154474A CA1154474A CA000369981A CA369981A CA1154474A CA 1154474 A CA1154474 A CA 1154474A CA 000369981 A CA000369981 A CA 000369981A CA 369981 A CA369981 A CA 369981A CA 1154474 A CA1154474 A CA 1154474A
- Authority
- CA
- Canada
- Prior art keywords
- net
- racquet
- frame
- thickness
- width
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
ABSTRACT
A game racquet having an elastic net and a frame molded in unison, the net comprising elastic elements which work primarily in bending and whose cross sectional area and thus the stiffness of the net increases toward the centre of the net.
A game racquet having an elastic net and a frame molded in unison, the net comprising elastic elements which work primarily in bending and whose cross sectional area and thus the stiffness of the net increases toward the centre of the net.
Description
` 1 1~4474 a The pre&cnt inVcntion ~elates to ~ molded game racquet.
Game racquets can be divided into two groups: The flrst group contains racquets which have little or practically no recoil system such as, for example, racquets made of a wood piece, where the recoiling action depends mostly on the t~
ball's elasticity. Examples of such stiff rackets can, for instance, be found described in U.S. patent numbers 3,934,876 and 3,879,035 of Haddad and oF Dan Chulis, respectively, or in most ping pong racquets. The second group contains rackets with a recoil mechanism, commonly in the form of an elastic net. Present racquets of this second group are generally produced by forming a separate frame on which tensioned strings are strung. This process, while producing an acceptable racquet, is costly and introduces some inherent drawbacks into the final product. For example, strings with aerodynamic cross-sections cannot be utilized in spite of their obvious advantage in minimizlng the drag, i.e., the air's resistance to the racquet's fast movement. Further, the strings' inherent ~;
uniformity prevents some desirable localized modification and further, since the `1 strings are not interlocked at their crossing junctions, and rely primarily on friction to hold their arrangement to the frame, every time the ball is hit the strings tend to mutually abrade, especially in the more loosely strung racquets, such as those for the game of racquet ball. The friction and abrasion between the strings dampens the recoil action of the net and thus reduces its effectiveness. In addition the minute residual relative displacement of the strings tends to accumulate and to create over tension in the lower area of the net (close to the handle) and looseness in the most important "sweet spot" area.
This degrades the racquet~s performance while structurally stressing the frame.
The present disclosure provides a molded racquet which circumvents the shortcomings and at tKe same time it is less costly to manufacture. `
At this point some discussion and comparison of the present disclosed ", , i ., ", ~
~...", .
::
-li~4(~74 :
racquet with the convention~l string rncq~let may be llelpful. When a balL hlts the net oE such a conventionnl racquet the net absorbs some o~ the ball's kinetic energy by its strings becoming tensioned and bent simultaneously, and as the strings return to their untensioned position some of this energy ls returned to the recoiling ball. However, the contribution of the string's unbending is so small that it can be ignored.
In the present disclosure the bending and consequent~ relaxation of the net elements is a major factor in the ball racquet recoil mechanism, and in some embodiments of the present invention the tension in the net's elements is purposely reduced and converted by means of a certain geometry to bending.
Some of the reasons for such preference are that such a geometry permits the net to store more energy without over stressing its elastic elements and that a moulding process controlling the net's geometry is relatively simple, whereas controlling the tension in molded strings presents quality control problems.
However, a molded racquet has some unique problems such as the net being very stiff and brittle in the area at which it connects to the frame, with a sharply declining spring rate toward the center. The present disclosure overcomes the problem of the peripheral net stiffness by employing an intrinsic net structure (the term "intrinsic net structure" means the net, viewed by itself, as if it was independent from the remaining racquet's structure) which has an intrinsic increasing stiffness, or spring rate, toward its center, so that when the net is included in the racket as an integral part the ball-recoiling characteristics of the racquet are evened.
The present disclosure overcomes the peripheral brittleness problem by having hinge means at the point where the frame and the net connect one to the other. This hinge means can be formed by locally reducing the thickness of the net's elastic elements (and increasing their width to maintain their tensile strength) or by forming a pronounced bend, as will be illustrated in the
Game racquets can be divided into two groups: The flrst group contains racquets which have little or practically no recoil system such as, for example, racquets made of a wood piece, where the recoiling action depends mostly on the t~
ball's elasticity. Examples of such stiff rackets can, for instance, be found described in U.S. patent numbers 3,934,876 and 3,879,035 of Haddad and oF Dan Chulis, respectively, or in most ping pong racquets. The second group contains rackets with a recoil mechanism, commonly in the form of an elastic net. Present racquets of this second group are generally produced by forming a separate frame on which tensioned strings are strung. This process, while producing an acceptable racquet, is costly and introduces some inherent drawbacks into the final product. For example, strings with aerodynamic cross-sections cannot be utilized in spite of their obvious advantage in minimizlng the drag, i.e., the air's resistance to the racquet's fast movement. Further, the strings' inherent ~;
uniformity prevents some desirable localized modification and further, since the `1 strings are not interlocked at their crossing junctions, and rely primarily on friction to hold their arrangement to the frame, every time the ball is hit the strings tend to mutually abrade, especially in the more loosely strung racquets, such as those for the game of racquet ball. The friction and abrasion between the strings dampens the recoil action of the net and thus reduces its effectiveness. In addition the minute residual relative displacement of the strings tends to accumulate and to create over tension in the lower area of the net (close to the handle) and looseness in the most important "sweet spot" area.
This degrades the racquet~s performance while structurally stressing the frame.
The present disclosure provides a molded racquet which circumvents the shortcomings and at tKe same time it is less costly to manufacture. `
At this point some discussion and comparison of the present disclosed ", , i ., ", ~
~...", .
::
-li~4(~74 :
racquet with the convention~l string rncq~let may be llelpful. When a balL hlts the net oE such a conventionnl racquet the net absorbs some o~ the ball's kinetic energy by its strings becoming tensioned and bent simultaneously, and as the strings return to their untensioned position some of this energy ls returned to the recoiling ball. However, the contribution of the string's unbending is so small that it can be ignored.
In the present disclosure the bending and consequent~ relaxation of the net elements is a major factor in the ball racquet recoil mechanism, and in some embodiments of the present invention the tension in the net's elements is purposely reduced and converted by means of a certain geometry to bending.
Some of the reasons for such preference are that such a geometry permits the net to store more energy without over stressing its elastic elements and that a moulding process controlling the net's geometry is relatively simple, whereas controlling the tension in molded strings presents quality control problems.
However, a molded racquet has some unique problems such as the net being very stiff and brittle in the area at which it connects to the frame, with a sharply declining spring rate toward the center. The present disclosure overcomes the problem of the peripheral net stiffness by employing an intrinsic net structure (the term "intrinsic net structure" means the net, viewed by itself, as if it was independent from the remaining racquet's structure) which has an intrinsic increasing stiffness, or spring rate, toward its center, so that when the net is included in the racket as an integral part the ball-recoiling characteristics of the racquet are evened.
The present disclosure overcomes the peripheral brittleness problem by having hinge means at the point where the frame and the net connect one to the other. This hinge means can be formed by locally reducing the thickness of the net's elastic elements (and increasing their width to maintain their tensile strength) or by forming a pronounced bend, as will be illustrated in the
- 2 -11~4~
following dlscussion.
~ore particularly in accordance with the inventlon there is provided in a molded game racquet comprising in combination a frame having a first t cross section with a flrst thickness and a first width, an elastic net moldecl in unison with said frame, said net comprising a plurality of elastLc elements each having a second cross section with a second thickness and a second wldth, said second thickness being substantially smaller than said first thickness and said second width being substantially smaller than said first width, the improvement wherein said second cross section increases in area toward the center of said net, so that the intrinsic stiffness of said ne~ by itself increases toward its center, said net forming an integral part of said racquet and the recoiling characteristics of a ball off various parts of the net thereby being evened. The net may be connected to the frame through hinge means and the net may comprise non-linear elements so as to increase the bending of the elements in response to the ball hitting the ~acquet. f Specific embodiments of the invention will now be described having reference to the accompanying drawings in which: ~, FIG. 1 shows a one half of a first embodiment of the present inventive subject matter.
FIG. 2 shows a cross section of the first embodiment as viewed along line 2-2 marked on FIG. 1.
FIG. 3 shows an enlarged section of PIG. 1 which is encircled by a phantom line 3-3 marked on FIG. 1, FIG. 4 shows a cross section of FIG. 3 as viewed along line 4-4 marked on FIG. 3, and FIG. 5 shows a one half of a second embodiment of the present inventive subject matter having a different net pattern.
' .
FIGS. 1, 2, 3, ~nd 4 show n moLded ~ame rac~ et 10 comprisin~ a frame ll having a firs~ cross-section 12 with a first tllickness 13 and a first width 14. An elastic net 15 is molded in unison with the frame 11 and a ~landle 16.
The net comprises a plurality of elastlc members 17 each havill~ a secolld ~ros<s section 18 with a second thickness l9 and a second wiclth 20 whLch arc substantially smaller than the first thickness and the first width, respectively.
The stiffness of the net 15 itself, when it is viewed b~ itself and t not as a part of the racket 10, increases toward its center, so that, when it is P
integral with the frame 11 the recoil effect of a ball off various parts of the net is evened, To lncrease stiffness of the net structure in the center various methods can be employed, for example, the net can be made denser toward the center and/or i' thicker. The denser net configuration is illustrated in FIG. l and 5, and the ~`
thickening of the elastic members 17 toward the center of the net is illustratedin FIG. 2 in conjunction with the first embodiment.
The reason that the net periphery tends to act stiffer when made an integral part of the racket 10 is that the elastic elements 17 connecting to the frame act as cantilevered members. In order to minimize this phenomenon and in order to minimize the net's brittleness in the area at which it connects to the frame 11, the net 15 is connected through hinge means 21 to the frame ll.
Such hinge means 21 are an integral part of the molded frame ll and net 15 and the hinge effect is achieved due to local geometry modifications. In the first embodiment this is done by reducing the second thickness 19' and increasing the second width 20' in order to minimize the above discussed cantilever effect while maintaining the net's tensile strength, and in the second embodiment the hinge means is provided by strongly curving the elastic element 21'.
The net in both embodiments is formed of non-linear elastic elements - 4 - i.
, ~
iis44~4 (the term `'non-linear" ns used hereln mean~ that the elastic eLements do not form a straight line between hinge points 21, or 21~, but intermittently change direction along the way, in contrast to conventional racquet's strings, which do) since this configuration reduces the tension and lncreases the bending of the ~i.
elastic elements 17 when the ball hits the net 15. This bias of developing bending stresses in the net instead of the conventlonal tension is preferable, since tension, and pre-tension, in a molded racquet is hard to control uniformlyfrom one racquet to another, and in various parts of the net 15, whereas the bending characteristics are dictated by the geometry and therefore are easily controllable. The non-linearity of the elastic elements 17, as illustrated in FIGS. 1 and 5 prevents substantial tension from developing in them.
The second embodiment 110 has similar characteristics as the first embodiment although its specific construction is somewhat different: The net 115 is made of straight and rounded elastic members 117 and 170 respectively andhinge means 21' are different from those of the firsl embodiment as previously ;~ discussed.
Although the present inventive subject matter has been illustrated with a limited number of embodiments it is to be understood that various modifications and substitutions can be made without departing from the spirit of the invention~0 or the scope ot the claims.
:: L
. ~ ~
~ L
,
following dlscussion.
~ore particularly in accordance with the inventlon there is provided in a molded game racquet comprising in combination a frame having a first t cross section with a flrst thickness and a first width, an elastic net moldecl in unison with said frame, said net comprising a plurality of elastLc elements each having a second cross section with a second thickness and a second wldth, said second thickness being substantially smaller than said first thickness and said second width being substantially smaller than said first width, the improvement wherein said second cross section increases in area toward the center of said net, so that the intrinsic stiffness of said ne~ by itself increases toward its center, said net forming an integral part of said racquet and the recoiling characteristics of a ball off various parts of the net thereby being evened. The net may be connected to the frame through hinge means and the net may comprise non-linear elements so as to increase the bending of the elements in response to the ball hitting the ~acquet. f Specific embodiments of the invention will now be described having reference to the accompanying drawings in which: ~, FIG. 1 shows a one half of a first embodiment of the present inventive subject matter.
FIG. 2 shows a cross section of the first embodiment as viewed along line 2-2 marked on FIG. 1.
FIG. 3 shows an enlarged section of PIG. 1 which is encircled by a phantom line 3-3 marked on FIG. 1, FIG. 4 shows a cross section of FIG. 3 as viewed along line 4-4 marked on FIG. 3, and FIG. 5 shows a one half of a second embodiment of the present inventive subject matter having a different net pattern.
' .
FIGS. 1, 2, 3, ~nd 4 show n moLded ~ame rac~ et 10 comprisin~ a frame ll having a firs~ cross-section 12 with a first tllickness 13 and a first width 14. An elastic net 15 is molded in unison with the frame 11 and a ~landle 16.
The net comprises a plurality of elastlc members 17 each havill~ a secolld ~ros<s section 18 with a second thickness l9 and a second wiclth 20 whLch arc substantially smaller than the first thickness and the first width, respectively.
The stiffness of the net 15 itself, when it is viewed b~ itself and t not as a part of the racket 10, increases toward its center, so that, when it is P
integral with the frame 11 the recoil effect of a ball off various parts of the net is evened, To lncrease stiffness of the net structure in the center various methods can be employed, for example, the net can be made denser toward the center and/or i' thicker. The denser net configuration is illustrated in FIG. l and 5, and the ~`
thickening of the elastic members 17 toward the center of the net is illustratedin FIG. 2 in conjunction with the first embodiment.
The reason that the net periphery tends to act stiffer when made an integral part of the racket 10 is that the elastic elements 17 connecting to the frame act as cantilevered members. In order to minimize this phenomenon and in order to minimize the net's brittleness in the area at which it connects to the frame 11, the net 15 is connected through hinge means 21 to the frame ll.
Such hinge means 21 are an integral part of the molded frame ll and net 15 and the hinge effect is achieved due to local geometry modifications. In the first embodiment this is done by reducing the second thickness 19' and increasing the second width 20' in order to minimize the above discussed cantilever effect while maintaining the net's tensile strength, and in the second embodiment the hinge means is provided by strongly curving the elastic element 21'.
The net in both embodiments is formed of non-linear elastic elements - 4 - i.
, ~
iis44~4 (the term `'non-linear" ns used hereln mean~ that the elastic eLements do not form a straight line between hinge points 21, or 21~, but intermittently change direction along the way, in contrast to conventional racquet's strings, which do) since this configuration reduces the tension and lncreases the bending of the ~i.
elastic elements 17 when the ball hits the net 15. This bias of developing bending stresses in the net instead of the conventlonal tension is preferable, since tension, and pre-tension, in a molded racquet is hard to control uniformlyfrom one racquet to another, and in various parts of the net 15, whereas the bending characteristics are dictated by the geometry and therefore are easily controllable. The non-linearity of the elastic elements 17, as illustrated in FIGS. 1 and 5 prevents substantial tension from developing in them.
The second embodiment 110 has similar characteristics as the first embodiment although its specific construction is somewhat different: The net 115 is made of straight and rounded elastic members 117 and 170 respectively andhinge means 21' are different from those of the firsl embodiment as previously ;~ discussed.
Although the present inventive subject matter has been illustrated with a limited number of embodiments it is to be understood that various modifications and substitutions can be made without departing from the spirit of the invention~0 or the scope ot the claims.
:: L
. ~ ~
~ L
,
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a molded game racquet comprising in combination a frame having a first cross section with a first thickness and a first width, an elastic net molded in unison with said frame, said net comprising a plurality of elastic elements each having a second cross section with a second thickness and a second width, said second thickness being substantially smaller than said first thickness and said second width being substantially smaller than said first width, the improvement wherein said second cross section increases in area toward the center of said net, so that the intrinsic stiffness of said net by itself increases toward its center, said net forming an integral part of said racquet and the recoiling characteristics of a ball off various parts of the net thereby being evened.
2. A racquet as defined in Claim 1 wherein said net is connected to said frame through hinge means.
3. A racquet as defined in Claim 1 where said net comprises non-linear elements so as to reduce the tension and increase the bending of said elements in response to the ball hitting said racket.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/124,571 US4339130A (en) | 1979-03-01 | 1980-02-25 | Game racket |
| US124,571 | 1980-02-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1154474A true CA1154474A (en) | 1983-09-27 |
Family
ID=22415641
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000369981A Expired CA1154474A (en) | 1980-02-25 | 1981-02-03 | Molded racquet |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1154474A (en) |
-
1981
- 1981-02-03 CA CA000369981A patent/CA1154474A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4664383A (en) | Iron-type golf club head | |
| US4084399A (en) | Gut for racket | |
| US4754968A (en) | Racket having unique stringing pattern | |
| US4196901A (en) | Tennis racquet | |
| US4249731A (en) | Game racket | |
| US1531862A (en) | Metal stringing for tennis rackets | |
| JPS59501099A (en) | Tennis or skate racket | |
| US4322076A (en) | Ball-playing racket | |
| US4909510A (en) | Sports racquet netting | |
| US4299385A (en) | Racquet | |
| US4339130A (en) | Game racket | |
| CA1154474A (en) | Molded racquet | |
| US4786055A (en) | Sports racquet | |
| US7285062B2 (en) | Racquet having cantilevered hoop portions | |
| US5562283A (en) | Sports racquet having power ring | |
| CA1154475A (en) | Molded racquet | |
| US4591165A (en) | Racket having strings which pass over rockable tension transmitting means | |
| US4913430A (en) | Tennis racket strings having orthogonally directed protrusions for enhancing the grip when in contact with a tennis ball | |
| US5158288A (en) | Tennis racket frame with multiple cross-sectional shapes | |
| US4964635A (en) | Tennis racket | |
| US5342045A (en) | Reverse sunburst string pattern for racquetball rackets | |
| US4903967A (en) | Racket frame having holes for tailoring frame stiffness | |
| JP3629642B2 (en) | Artificial material shuttlecock | |
| WO1994011064A1 (en) | Hybrid stringing arrangement of main and cross strings with enhanced performance characteristics for use in a sports racket | |
| US5816958A (en) | Tennis racket |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |