CA1186880A - Method of making a racket frame - Google Patents
Method of making a racket frameInfo
- Publication number
- CA1186880A CA1186880A CA000392174A CA392174A CA1186880A CA 1186880 A CA1186880 A CA 1186880A CA 000392174 A CA000392174 A CA 000392174A CA 392174 A CA392174 A CA 392174A CA 1186880 A CA1186880 A CA 1186880A
- Authority
- CA
- Canada
- Prior art keywords
- racket frame
- making
- strip members
- racket
- structural member
- 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
Landscapes
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
ABSTRACT
A racket frame is made by molding a thermosetting resin composition together with reinforcing fibers. Molds are made of flexible strip members, such as plastics, wood pulp, paper pulp, wood, bamboo, etc., which are bent to form a racket frame in a fitting, thereby reducing the production cost incurred in fabrication of expensive molds. The formed racket frame has no shell and core structure.
A racket frame is made by molding a thermosetting resin composition together with reinforcing fibers. Molds are made of flexible strip members, such as plastics, wood pulp, paper pulp, wood, bamboo, etc., which are bent to form a racket frame in a fitting, thereby reducing the production cost incurred in fabrication of expensive molds. The formed racket frame has no shell and core structure.
Description
~IrTI-101) c)~ E'l'ODUC_[i~G A P~CKI~T ~T~
F~CKGROIJND ()~ Tl-lE :LNVENTI()N
'I'his invention relates to a methocl of produc:ing a racket frame in which a fiber r.e-inforced thermosetting resin is molded into a racket frame.
Composite racket frames generally include a she]l made of a plurality of layers of thermorsetting resin-impregnated woven glass fibers or graphite fibers and a foam core intimately bonding with the shell. During the processing of such composite structure it usually need an internal pressure to fo ce the shell to closely contact with the inner wall of the mold cavity to take the shape thereof. There are two met:hods of generating a sufficient internal pressure, i.e. direct method (blow molding) and indirect method (foam molding~. In the first: method the shell side -;s orced by the compressecl air to closely contact with the inner wall of the mold cavity to take a predetermined shape. The holloTi7 central portion is then provided with a foamable thermoplastic composition which will then be foamed and cured therein by heating. This additional step may incur further expenses during processing.
In the second method, a plurality of resin-impregnated woven`fibers layers are wrapped around a foamab]e core composition and then put into a mold cavity for molding.
When heating the foaming agent activates the core composition to generate a pressure to produce a desired molded shape after curing. Although the latter method is more simpler than the former one, the temperature Eor gelling and curing the resin-impregna-ted fibers and for foarning the thermoplastic resin are not -the same. Therefore the pressure generated are not controllable and the resin from the core may pene~
trate into the shell layers, thereby destroying the orien-tation of the fiber as well as the reinforcement thereof.
According -to the present invention there is pro-vided a method for making a racket rrame comprising: the steps of preparing two elongated strip members eachincluding two racket handle portions and a racket head portion inter-mediate said racket handle portions and defining an elongatedmold cavity section extending throughout its length, placing a thermosetting resin composition and fibres for reinforcing into the mold cavity sections, bringing said two s-trip mem-bers together in face-to-face relation with the mold cavity sections thereof in opposing relation to each other to form a structural member defining an elongated mold cavity contain-ing said thermoset-ting resin composi-tion and fibres, bending said strip members to form a shape of a racket frame, curing said thermose-tting resin composition, and removing the strip members which comprise said structural member after curing.
The structural member may have its cross-section in I-shape, concave lens shape or in the shape having a notch like part. The fibers used may be carbon fiber, glass fiber, boron fiber, kever or other reinforcing mater-ials.
The removal of strip members from the formed frame can be done either by grinding or by the use of a mold releasing agent.
Desirably the strip members comprise flexible members and said method includes the additional step of
F~CKGROIJND ()~ Tl-lE :LNVENTI()N
'I'his invention relates to a methocl of produc:ing a racket frame in which a fiber r.e-inforced thermosetting resin is molded into a racket frame.
Composite racket frames generally include a she]l made of a plurality of layers of thermorsetting resin-impregnated woven glass fibers or graphite fibers and a foam core intimately bonding with the shell. During the processing of such composite structure it usually need an internal pressure to fo ce the shell to closely contact with the inner wall of the mold cavity to take the shape thereof. There are two met:hods of generating a sufficient internal pressure, i.e. direct method (blow molding) and indirect method (foam molding~. In the first: method the shell side -;s orced by the compressecl air to closely contact with the inner wall of the mold cavity to take a predetermined shape. The holloTi7 central portion is then provided with a foamable thermoplastic composition which will then be foamed and cured therein by heating. This additional step may incur further expenses during processing.
In the second method, a plurality of resin-impregnated woven`fibers layers are wrapped around a foamab]e core composition and then put into a mold cavity for molding.
When heating the foaming agent activates the core composition to generate a pressure to produce a desired molded shape after curing. Although the latter method is more simpler than the former one, the temperature Eor gelling and curing the resin-impregna-ted fibers and for foarning the thermoplastic resin are not -the same. Therefore the pressure generated are not controllable and the resin from the core may pene~
trate into the shell layers, thereby destroying the orien-tation of the fiber as well as the reinforcement thereof.
According -to the present invention there is pro-vided a method for making a racket rrame comprising: the steps of preparing two elongated strip members eachincluding two racket handle portions and a racket head portion inter-mediate said racket handle portions and defining an elongatedmold cavity section extending throughout its length, placing a thermosetting resin composition and fibres for reinforcing into the mold cavity sections, bringing said two s-trip mem-bers together in face-to-face relation with the mold cavity sections thereof in opposing relation to each other to form a structural member defining an elongated mold cavity contain-ing said thermoset-ting resin composi-tion and fibres, bending said strip members to form a shape of a racket frame, curing said thermose-tting resin composition, and removing the strip members which comprise said structural member after curing.
The structural member may have its cross-section in I-shape, concave lens shape or in the shape having a notch like part. The fibers used may be carbon fiber, glass fiber, boron fiber, kever or other reinforcing mater-ials.
The removal of strip members from the formed frame can be done either by grinding or by the use of a mold releasing agent.
Desirably the strip members comprise flexible members and said method includes the additional step of
- 2 -placiny the structural member in a Fitt-ing.
Thus the present invention provides a method which is applied for producing a fiber reinforced solid racket frame with no internal pressure to be provided during mold-ing so as to take the shape o-f the mold.
The present inven-tion will be fur-ther illus-tra-ted by way o-F the accompanying drawings, in which:-Fig. 1 is a perspective view o-F a racke-t frame according to the present invention;
Fig. 2a is a perspective view of a flexible strip member accor~ing to the invention;
Fig. 2b is a perspective view o-F a s-trip member filled with a mold compound;
Fig. 2c is a cross-section of two abu-tted strip members;
Fig. 2d is a plan view of a racket frarne;
Fig. 2e is a cross-section oF a racke-t frame in a first embodimen-t according to -the invention;
Fig. 3 is a cross-section of a racke-t frame in a second embodiment according -to the present invention;
Fig. ~ is a cross-section of a racket frame in a third embodiment of the invention; and Fig. 5 is a cross-section of a racket frame in a fourth embodiment of the invention.
3i~3 As shown in Figs. I and 2 a racket frallle IU accord-ing to the invent-ion is made oF a thermosetting resin rein-forced with -fibers, such as carbon Fiber, ylass fibers, - 3a -i`:; k e~ f f~ J
~ bol-on fibers, k~ , eLc., by cast mo:Lding. Mo.Lds used -i.n chi.s :invention are :Elexible strLp members 11 having a length running from the handle portion, around the head port:lon and then `back to the handle portion. Each of these strip members 11 has a mold cavity 13 throughout its length and two mold cavities aEter bringing together can form a structural member in the foms, such as I-shape (Fig. 2e), concave lens-Shape, (Fig. 3), rectangle with one side thereof grooved, (Fig. 4), rectangle with one side grooved and other side round (Fig.5).
These strip members 11 are used in place of rigid mol'ds which may incur higher cost of molds fabrication. They are made of materials such as plastics, wood pulp, paper pulp, wood bamboo, etc. The plastic strip member can be made by extrusion or injection molding 7 whereas wood or bamboo can be machined to obtain a mold cavity.
During processing, the strip members 11 are fill.ed with the thermosetting resin and fibers 14 and then two strip members 11 are brought together and bent into a racket frame shape which is then placed in a fitting for molding.
20 In Fig. 3 two strip members 21 provide a racket frame 22 with its cross-section in a concave-lens shape. As shown in Fig. 4 two strip members 31 and 41 provide a frame having its cross-section in a combined rectangular shape 42 and U-shape 32. In Fig. 5 one strip member 51 has a groove in U-shape 52 and another strip member 61 has a curved groove 62. The groove 62 is firstly provided with a layer of fibers reinforced resin 63 and then filled with a wooden layer 6~. T~o strip membe~s 51 and 61 are brought t~gether and bent lnto a racket frame shape.
Aften~ards, the resin is cured at a certain temperature. After curing the strip members can be removed by the use of a mold releasing agent or by grinding.
z~ ~.f v
Thus the present invention provides a method which is applied for producing a fiber reinforced solid racket frame with no internal pressure to be provided during mold-ing so as to take the shape o-f the mold.
The present inven-tion will be fur-ther illus-tra-ted by way o-F the accompanying drawings, in which:-Fig. 1 is a perspective view o-F a racke-t frame according to the present invention;
Fig. 2a is a perspective view of a flexible strip member accor~ing to the invention;
Fig. 2b is a perspective view o-F a s-trip member filled with a mold compound;
Fig. 2c is a cross-section of two abu-tted strip members;
Fig. 2d is a plan view of a racket frarne;
Fig. 2e is a cross-section oF a racke-t frame in a first embodimen-t according to -the invention;
Fig. 3 is a cross-section of a racke-t frame in a second embodiment according -to the present invention;
Fig. ~ is a cross-section of a racket frame in a third embodiment of the invention; and Fig. 5 is a cross-section of a racket frame in a fourth embodiment of the invention.
3i~3 As shown in Figs. I and 2 a racket frallle IU accord-ing to the invent-ion is made oF a thermosetting resin rein-forced with -fibers, such as carbon Fiber, ylass fibers, - 3a -i`:; k e~ f f~ J
~ bol-on fibers, k~ , eLc., by cast mo:Lding. Mo.Lds used -i.n chi.s :invention are :Elexible strLp members 11 having a length running from the handle portion, around the head port:lon and then `back to the handle portion. Each of these strip members 11 has a mold cavity 13 throughout its length and two mold cavities aEter bringing together can form a structural member in the foms, such as I-shape (Fig. 2e), concave lens-Shape, (Fig. 3), rectangle with one side thereof grooved, (Fig. 4), rectangle with one side grooved and other side round (Fig.5).
These strip members 11 are used in place of rigid mol'ds which may incur higher cost of molds fabrication. They are made of materials such as plastics, wood pulp, paper pulp, wood bamboo, etc. The plastic strip member can be made by extrusion or injection molding 7 whereas wood or bamboo can be machined to obtain a mold cavity.
During processing, the strip members 11 are fill.ed with the thermosetting resin and fibers 14 and then two strip members 11 are brought together and bent into a racket frame shape which is then placed in a fitting for molding.
20 In Fig. 3 two strip members 21 provide a racket frame 22 with its cross-section in a concave-lens shape. As shown in Fig. 4 two strip members 31 and 41 provide a frame having its cross-section in a combined rectangular shape 42 and U-shape 32. In Fig. 5 one strip member 51 has a groove in U-shape 52 and another strip member 61 has a curved groove 62. The groove 62 is firstly provided with a layer of fibers reinforced resin 63 and then filled with a wooden layer 6~. T~o strip membe~s 51 and 61 are brought t~gether and bent lnto a racket frame shape.
Aften~ards, the resin is cured at a certain temperature. After curing the strip members can be removed by the use of a mold releasing agent or by grinding.
z~ ~.f v
Claims (8)
1. A method for making a racket frame comprising the steps of preparing two elongated strip members each including two racket handle portions and a racket head por-tion intermediate said racket handle portions and defining an elongated mold cavity section extending throughout its length, placing a thermosetting resin composition and fibres for reinforcing into the mold cavity sections, bringing said two strip members together in face-to-face relation with the mold cavity sections thereof in opposing relation to each other to form a structural member defining an elong-ated mold cavity containing said thermosetting resin compo-sition and fibres, bending said strip members to form a shape of a racket frame, curing said thermosetting resin composition, and removing the strip members which comprise said structural member after curing.
2. A method of making a racket frame as claimed in claim l, wherein said structural member has its cross-section in I-shape.
3. A method making a racket frame as claimed in claim 1, wherein said structural member has its cross-section in concave lens-shape.
4. A method of making a racket frame as claimed in claim 1, wherein said structuralmember has its cross-section having a notch like part.
5. A method of making a racket frame as claimed in claim 1, wherein the fibers are selected from the group consisting of carbon fiber, glass fiber and boron fiber.
6. A method of making a racket frame as claimed in claim 1, wherein the removal of strip members is done by grinding.
7. A method of making a racket frame as claimed in claim 1, wherein the removal of strip members is done by means of a mold releasing agent.
8. A method for making a racket frame as claimed in claim 1, wherein said strip members comprise flexible members and said method includes the additional step of placing the structural member in a fitting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000392174A CA1186880A (en) | 1981-12-14 | 1981-12-14 | Method of making a racket frame |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000392174A CA1186880A (en) | 1981-12-14 | 1981-12-14 | Method of making a racket frame |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1186880A true CA1186880A (en) | 1985-05-14 |
Family
ID=4121616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000392174A Expired CA1186880A (en) | 1981-12-14 | 1981-12-14 | Method of making a racket frame |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1186880A (en) |
-
1981
- 1981-12-14 CA CA000392174A patent/CA1186880A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |