Patent GB-316824-A (GB)
Title: Means for stringing tennis rackets
IPC: A63B51/14
Filed: 1928-11-13
Abstract: 316,824. Wiener Edelsaitenfabrik Ges. Oct, 17, 1928, [Convention date]. Addition to 312.883. Rackets.-The apparatus for stringing tennis rackets, described in the parent Specification is modified by (a) providing clamping jaws 150, 151 and 168, 169, Fig. 2, for holding respectively the handle and sides of the racket, (b) mounting each string-clamping and tensioning device D upon a shaft 124 so as to apply tension to the string by making a rotational movement, (e) utilizing a string holder E for holding the tensioned string, and (d) providing the elements 208, 209, Fig. 5, (utilized for separating the alternate longitudinal strings to form the " shed " prior to threading the transverse string) with hooked extremities for engaging the strings. An auxiliary tool is also provided for threading the transverse strings through the shed formed by the longitudinal strings. In using the apparatus, the racket, previously pro. vided with the longitudinal strings, is laid in the device and a hand-wheel 153, Fig. 2, is turned to clamp the racket handle between the jaws 150, 151. The sides of the racket are secured in the clamping jaws 168, 169 which may be closed by cam handles 171. The clamping jaws at opposite sides of the racket are connected by linkage so that they may be moved bodily, only in unison and to the same extent, thereby preventing distortion of the racket frame. The clamping devices D are now adjusted along the shafts 124, a hand-wheel 235, Fig. 5, is rotated to bring the two sets of shedforming hooks 208, 209 into their lowermost position below the racket, and the frame carrying the shed-forming device is moved along bars 155, 156 to its operating position. The handwheel 235 is now rotated in the reverse direction thereby raising the hooks so that the longitudinal strings may be engaged therewith. On rotating a further handwheel 226 a rack-and-pinion gear moves the two sets of hooks in opposite directions and forms the shed. The end of the transverse string may now be drawn through the shed by means of a tool of lazy-tong formation and passed between the corrugated gripping surfaces of one of the clamping and tensioning devices D, either of which may be coupled to a pedal by a hand-operated clutch. By operating the pedal a cord 120 or 121 turns the corresponding shaft 124 and by means of a crank arm 143 thereon, Fig. 6, closes the upper jaw 136 of the clamp upon the lower loose jaw 130 thereby first gripping the interposed string and then rotating the two jaws together so as to tighten the string, the extent of the stretching being indicated bv a graduated scale 139, Fig. 2, carried by the shaft 124. A tension measurer 128 operated from the shaft 124 indicates the tension in kgms. Before releasing the clamp from the strained string the string holder E is slid into position and its jaws are clamped upon the string by a hand-operated cam. A similar stringing operation may now be performed in the opposite direction. In a modification, the clamps D are each formed of two jaws pivoted together one of the jaws being keyed on the shaft 124. Instead of employing a lazytong device for passing the transverse string through the longitudinal strings the device shown in Figs. 22, 23 may be employed. This consists of a bar 250 placed across the racket and bearing a vertical tube 251 rotatable by a handle 252 and terminating in an horizontal lower portion 253. Slidable within the tube, without rotation therein, is a rod 260, 254 with a flexible section 259. The upper end of the rod bears an arm 255 guided by a cam surface 257. The transverse string 190 may be clamped to the lower end of the rod. On turning the handle 252 the cam surface 257 causes the string to be passed across the racket in an approximately transverse direction. Instead of being pedal driven, the machine may be driven by an electric motor, and a number of machines may be driven by the motor so as to be worked at the same rate.