Patent GB-418982-A (GB)
Title: Improvements in or relating to the manufacture of rackets for lawn tennis and other games
IPC: B27M3/22
Filed: 1933-04-05
Abstract: 418,982. Bending racket frames. NASH, R. J., Nelson Passage, High Street, Birmingham. April 5, 1933, No. 10164. [Class 145 (ii).] During the bending of a strip into racket shape, tension is applied to a band associated therewith and/or to the strip itself. The plywood strip 6, Fig. 1, comprising the frame material is wrapped progressively about a core 4 by rollers 5 which are progressed around the contour of the core. The core 4 comprises two semielliptical portions having spindles 30, 31 respectively by which they are secured in the machine. The spindle 30 seats on a ledge 32 on the machine frame, being retained by a pivoted member 33 ; the spindles 30, 31 engage a slot 34 in a vertical guide 35 mounted on the machine. The rollers 5, which may be rubber covered, are detachably mounted on horizontal links 10 connected by pivoted arms 9 with a horizontal member 8 constrained to move vertically by a peg 8<a> thereon engaging the slot 34 in the guide 35. Each link 10 is connected by a link 24 with a gear wheel 23, rotation of which causes the links 10 to carry the rollers 5 around the core 4. The gear wheels may be operated by hand, or by an electric motor 40 through gearing 41, 42 ; hand-operated gear 43 serves to re-set the machine at the completion of a bending operation. A band 1 of flexible sheet material is interposed between the strip 6 and rollers 5 ; each end of the band 1 is engaged by a friction grip brake, comprising plates 11, 12 faced with friction material and pivoted at 11<a>, 12a to the link 10; the end 13 of the plate 12 is acted upon by a screw 14 carried by a lever 15 pivoted to the link 10; the lever 15 is connected by a link 15<c> to one arm 17 of a bellcrank lever pivoted to the member 8. A rod 19 extends through the arms 17<a> of the bell-crank levers, and springs 20 are mounted between the arms 17<a> and collars 19<a> mounted on the ends of the rod. This arrangement equalizes the pressure of the friction brakes. As the links 10 move around the core 4 as described above, the band 1 is wrapped progressively around the core, ensuring close contact between the strip 6 and core 4 ; the band 1 slips through the brakes and its tautness pulls the links 10 towards each other, thus applying the desired pressure to the rollers 5. Alternatively, the plywood strip 6 is itself passed through the friction brakes, the band 1 being dispensed with, or both the strip 6 and band 1 may be tensioned. In a modified construction, the ends of the band 1 are secured to rotary brakes carried by the links 10. In another modification, the ends of the band 1 are connected by cables to a single rotary brake carried by the member 8, the cable passing around pulleys mounted on the links 10 and on the member 8, and around a pulley pivotally mounted on the latter to equalize the pressure. In a further modification, the ends of the band 1 are secured to bell-crank levers pivoted on the links 10, the other ends of the bell-crank levers being connected to pistons moving in cylinders carried by the member 8 and connected with a source of constant fluid pressure. In a further modification, Fig. 9, the rollers 5 are mounted on the rods 57 of pistons 58 moving in cylinders 59, the pressure of the rollers 5 on the work being thus effected by fluid pressure supplied to the cylinders ; the latter are moved around guides 60 by suitable gearing to progress the rollers around the core. The band is tautened by rotary brakes 61 carried by the piston rods. At the end of the bending operation, Fig. 5, endless chains 36 are placed over the ends of the spindles of the rollers 5, the flights of the chain being pressed together by a bolt and nut 38 engaging the spindle 30 ; the handle portion may be engaged by a clamp 29. The core, rollers, strip and other associated members can then be removed bodily from the machine, either manually or by suitable hoisting means. A racket wedge, e.g. as described in Specification 418,985, may be placed on the top half of the core before bending commences ; preferably an insertion is incorporated into the frame, and a spare insertion made during bending, as described in Specification 418,983.