US2154870A - Apparatus for stringing tennis rackets - Google Patents

Description

April 18, 1939. Epl-l, SERRANO APPARATUS FOR STRINGING T ENNIS RACKErIS Filed June lO, 1936 3 Sheets-Sheet l Il l lllllll 3mm. Se frana April 1s, 1939.

E. H. SERRANO APPARATUS FOR STRINGING TENNIS RACKETS 3 Sheets-Sheet 2 Filed June 1o, 195e EHSfF/TZO pf 18, 93@ 'E H SERRANO S-,g'o

APPARATUS FOR STRINGNG TENNIS RACKETS Filed June lO, 1936 3 Sheets-Sheet 3 A@wem/bof@ Serra n GMM/MAMA Patented Apr. 18, 1939 UNITED STATES PATENT OFFICE APPARATUS FOR STRINGING TENNIS RACKETS 4 Claims.

This invention relates to certain new and useful improvements in apparatus for stringing tennis rackets.

An object of the invention is to provide apparatus for the Stringing of tennis rackets and including a tensioned device that is manually operated for the stretching of a string and constructed in a manner whereby a pulling strain on the string beyond a predetermined point is removed so that the strings may be stretched to the desired degree regardless of continued movement of the tensioning device.

A further object of the invention is to provide apparatus for the Stringing of tennis rackets that includes a support for the racket with a string tensioning device movably supported relative to the racket for positioning relative to the string openings in the racket frame with means for holding the tensioning device against movement whereby the hands of the operator are free for other work in connection with the Stringing of the racket.

With the above and other objects in View that will become apparent as the nature of the invention is better understood, the same consists in the novel form, combination and arrangement of parts hereinafter more fully described, shown in the accompanying drawings and claimed.

In the drawings:

Figure l is a top plan view of apparatus for Stringing tennis rackets constructed in accordance with the present invention and illustrating a tensioning device for the string engaged with the frame of the tennis racket and illustrated by dotted lines in a shifted position;

Figure 2 is a side elevational view, partly in section, showing the adjustable mounting for the brackets that support the string tensioning device;

Figure 3 is a fragmentary sectional view of the string tensioning device, the string frame of the tennis racket and an arm of a string clamp;

Figure 4 is a detail sectional view taken on line 4--4 of Figure 3, showing a tennis string encircling the drum or casing of the tensioning device and a part of the string frame of the racket with the string extending through an opening in the frame;

Figure 5 is a top plan View of the string tensioning device showing a scale or gage for determining pulling strains on the strings;

Figure 6 is a detail sectional View taken on line 6 6 of Figure 2, showing the string clamp and the removable handle for positioning on either side of the clamp;

Figure 7 is a plan view of one of the friction disks in the string tensioning device;

Figure 8 is a detail sectional View taken on line 8 8 of Figure l, showing the clamping device for the handle of the tennis racket;

Figure 9 is a detail sectional View taken on line 9--9 of Figure 2, showing mounting bars for the string clamp;

Figure 10 is a detail sectional View taken on line lil-l0 of Figure 1, showing the clamp for the outer end of the string frame of the tennis racket.

Referring more in detail to the accompanying drawings, and particularly to Figures 1 and 2, a tennis racket is illustrated and of the usual form that embodies an oval-shaped string frame that is carried by a handle 2 I, the tennis racket being mounted in a support and rigidly held therein during the Stringing operation. The string frame 2E! is provided with the string openings 22 as shown in Figure 2 for the passage of the strings Z3 shown in Figure l. A support for the tennis racket comprises a base block 24 adapted to be anchored to a table, bench 25 or the like and from which a standard 26 rises with clamping devices at the upper end of the standard 26 for the support of the handle 2l of the tennis racket as shown in Figures 1, 2 and 8. rI'he handle clamp comprises a U-shaped frame having a bottom wall 2l and upstanding side walls 28, a clamping plate 29 being associated with the inner side of each side wall 23 for direct engagement with the handle 2i of the tennis racket and to be moved into clamping engagement therewith by means of the clamping screws 30 threaded through the side walls 28, the clamping screws being preferably arranged to provide one clamping screw for a side wall intermediate the ends thereof and two spaced clamping screws for the other side wall of the clamp as shown in Figure 1, the screws being adjustable to obtain proper positioning of the tennis racket in the Stringing apparatus. A horizontal bar 3l projects from the lower end of the standard 2B beneath the tennis racket and terminates outwardly of the outer end of the string frame 2li and upon which end a support for the string frame of the racket is mounted. As shown more clearly in Figures 2, 9 and 10, an arm 32 has a bearing 33 at its lower end for mounting on the bar 3l, the arm being of angle formation to present the upper end 34 thereof for the support of the outer end of the string frame 20. The string frame of the racket is mounted on the upper end 34 of the arm 32 and a clamp plate 35 is engaged with the upper side of the string frame 20 and retained in clamping engagement therewith by means of the clamping screw 36 passing through an opening in the clamp plate 35 and having threaded engagement as at 31 with the upper end 34 oi the arm. It will therefore be seen that a rigid mounting is provided for the tennis racket.

The string tensioning device and support therefor is shown more clearly in Figures 1 to 5, the support including a bracket 38 projecting horivso zontally from the support 25 beneath the bar 3|, the bracket 38 terminating inwardly of the outer end of the bar 3| and to the outer end of which bracket, an arm 39 is pivotally mounted and retained in adjusted positions by means of the clamping screw 40. An upstanding bracket arm 4| is carried by the arm 39 and is slidably mounted thereon by means of the guide 42, a lug 43 at the outer end of the arm 3S preventing displacement of the guide 42 and the string tensioning device is mounted upon the upper end of the bracket arm 4|. As shown in Figure 3, the string tensioning device comprises a metallic cylinder 44 surrounded by a rubber casing 45 and about which the string 23 is adapted to be wound with the rubber casing preventing injury to the string as well as the outer edge of the string frame 26 of the racket. The upper end of the cylinder 44 is closed by a disk 46 and the lower end of the cylinder is closed by a disk 41 upon which the cylinder 44 and rubber casing 45 rests with a central upstanding portion 48 on the bottom disk 41 rising into the cylinder 44 as illustrated. A handle 46 projects peripherally from the bottom disk 41 for manipulation thereof. A spindle 56 located axially within the cylinder 45 has the upper end thereof threaded for the reception of a cap nut 5| that passes through a central opening in the top disk 46 for engagement with the upper threaded end of the spindle 58, the cap nut having a flange at its upper end engaged with the top disk 46 to retain the same in position in the cylinder 44. As shown in Figure 5, the top disk 46 is calibrated as at 52 in pounds tension and the cap nut 5| carries an indicator pointer 53 cooperating with the calibrations 52. The lower end of the spindle 56 extends through the disk 48 and also through a central opening in a top Wall 54 at the upper end of the bracket arm 4|, the spindle being freely rotatable through the bottom disk 48 and wall 54. A sleeve 55 is threaded onto the lower threaded end 56 of the spindle 56, the sleeve extending through an opening in the wall 54 and abuttingly engaging the lower side of the bottom disk 48, the sleeve 55 being retained in adjusted position by means of the lock nut 51 threaded onto the lower end of the spindle and engaged with the sleeve. For purposes presently to appear, a disk plate 58 is freely mounted on the sleeve 55 in flat engagement with the underside of the wall 54 and is retained in position on the sleeve by mating inclinedv surfaces 59 as illustrated. A handle 66 is pivotally mounted at one end as at 6| upon the disk plate 58 adjacent one side edge thereof, the handle 66 carrying a cam portion 62 adjacent its pivot point for engagement with the wall 54 for holding the spindle 56 against rotation. A series of metallic and bre disks 63 are mounted on the spindle 50 and rest upon the upper face of the extension 48 of the bottom disk 41, selected ones of the disks 63 as shown in Figure '7 having diametrically opposite peripheral lug projections 64 that work in side slots 65 in the cylinder 44 to retain certain ones of the metallic disks 63 against rotation while other disks 63 having square central openings tting on a squared portion of the shaft 56 as shown in Figure 4 to rotate with the shaft to produce friction between the disks during relative movements of the disks that is shown on the indicator devices 52 and 53. A series of coil springs 66 are interposed between the top disk 46 and the upper friction disk 63 within the cylinder 44, the springs being retained in position by pins 61 depending from the top disk 46 and lugs 68 struck out and rising from the top friction disk 63. When the cap nut 5| is rotated by the insertion of an implement in the opening 5|arr thereof, the indicator finger 53 is caused to register with the desired calibration 52 indicating tension in pounds and during such movement, the top disk 46 of the cylinder 44 is lowered into the cylinder for compression of the springs 66 for increasing friction between the several disks 63. The tennis racket string 23 is passed around the cushion covering 45 on the tensioning device as shown at 23a, the elastic covering 45 preventing slippage of the looped portion 23a of the string, the tensioning device being positioned with respect to the string frame 20 of the racket as shown in Figures 1 to 4. The handle 49 of the tensioning device rotates the cylinder 44 to place the string 23 under the desired tension and when such tension has been attained as determined by the initial setting point of the dial of the tensioning device, the string tension i overcomes friction between several friction disks 63, the bottom disk 41 of the cylinder 44 and the wall 54 at the upper end of the bracket arm 4|, the handle at this moment being permitted to move independently of the cylinder 44 so that only a predetermined degree of tension can be imparted to the string 23.

When the tennis racket string 23 has been placed under the desired tension, a clamp is engaged with the string Within the frame 20 of the tennis racket for holding the string against movement relative to the racket frame 26 and permitting shifting movement of the tensioning device to a position for stretching a string through another opening 22 of the racket frame. Before the clamp is engaged with the string, the tensioning device is restrained from movement after having placed the string under the desired tension by means of the lever 68 that moves its cam 62 into engagement with the wall 54 at the upper end of the bracket arm 4 i, this action causing the plate 58 to lower the spindle 56 by its engagement with the threaded sleeve 55 for causing a further compression of the springs 66 and correspondingly increased pressure on the friction disks 63. The tensioning device is thereby held against rotary movement on the bracket arm 4| until the clamp is engaged with the string and at which time the tensioning device may be released. The string clamp and support therefor are shown more clearly in Figures 1 to 3, 6 and 9, the support including a pair of horizontal arms 69 projecting respectively from opposite sides of the bar 3| adjacent the lower end of the standard 26 that rises from the base block 24 with a rod 16 having a bearing sleeve 1| at one end mounted on each arm 69. The support for the forward ends of the rods 16 includes a pair of interiitting blocks 12 slidably mounted upon the bar 3| and as shown in Figures 2 and 9, each block 12 carries an outwardly directed arm 13 having a longitudinal groove 14 in one side thereof for receiving the reduced pin end 'l5 of the adjacent rod 16, the rods 16 supporting the clamps for Stringing the lateral strings while the clamps are mounted on the arms 13 when Stringing the cross strings. The string clamp per se as shown in detail in Figure 6 comprises a pair of clamp plates 16 having semi-circular barrel portions 11 at their lower ends for engagement with the rods 10 as shown in Figure 6 or for engagement with the arm 13. The upper ends of the clamp plates 16 are serrated as at 18 to provide spaced fingers 19 to facilitate positioning of the upper ends of the clamp plates through crossed strings for clamping engagement with a string. The connection between the two clamp plates 16 comprises a headed screw bolt 80 freely passing through the clamp plates intermediate the ends thereof, a handle 8i for operation of the clamp plates 16 being mounted upon the threaded ends of the bolt 80 and retained thereon by the nut 82. The pivoted end of the handle 8| carries a cam block 83 for effecting movements of the clamp plates toward and away from each other. A coil spring 84 is interposed between the clamp plates 'Iii to effect separation thereof for releasing the engagement between the clamp plates and the string 23 and also the supporting rod lo or arm 13, the screw bolt 80 and operating handle 8| being reversible for mounting upon either side of the clamp plate as may be desired in connection with the Stringing of a tennis racket. When the desired tension has been placed upon the string 23 by the tensioning device and the latter restrained from movement by the locking lever Eil and cam 62, the clamp plates are then engaged with a string, whereupon the tensioning device may be released and shifted by its pivotal and slidable mounting to a position to receive a string to be wound thereon from the adjacent racket frame opening 22. The supporting rods 'I0 are used for the mounting of the clamps when Stringing the lateral strings and these rods 10 may be removed and the clamps mounted on the arms 'I3 when Stringing the cross strings of the racket frame.

From the above detailed description of the invention, it is believed that the construction and operation thereof will at once be apparent and while there are herein shown and described the preferred embodiments of the invention it is nevertheless to be understood that minor changes may be made therein without departing from the spirit and scope of the invention as claimed.

I claim:

l. In the Stringing of tennis rackets, wherein a string tensioning device is adapted to have a string coiled therearound to exert a pulling force on a string threaded through a tennis racket and to be uneffective during continued movement after the string has received the desired tension, and wherein a tensioned portion of the string is held under tension while the tensioning device is being engaged with another portion of the string and wherein means is provided for holding the tensioning device against movement, a tensioning device including a handle having a disk at one end, a rubber covered cylinder supported on the disk and about which the string is adapted to be coiled, a friction device within the cylinder and associated with the disk, and means for Variably tensioning the friction devices whereby a predetermined tension may be applied to the string.

2. lIn the Stringing of tennis rackets, wherein a string tensioning device is adapted to have a string coiled therearound to exert a pulling force on a string threaded through a tennis racket and to be uneifective during continued movement after the string has received the desired tension. and wherein a tensioned portion of the string is held under tension while the tensioning device is being engaged with another portion of the string and wherein means is provided for holding the tensioning device against movement, a tensioning device including a handle having a disk at one end, a cylinder mounted on said disk, a spindle journaled through the disk, a calibrated disk at the outer end of the cylinder, an indicator finger on the outer end of the spindle cooperating with the calib-rated disk, and spring devices associated with the cylinder, spindle and disk for variably tensioning the handle disk whereby a predetermined tension may be applied to the string.

3. In the Stringing of tennis rackets, wherein a string tensioning device is adapted to have a string coiled therearound to exert a pulling force on a string threaded through a tennis racket and to be uneffective during continued movement aiter the string has received the desired tension, and wherein a tensioned portion of the string is held under tension while the tensioning device is being engaged with another portion of the string and wherein means is provided for holding the tensioning device against movement, a tensioning device including a handle having a disk at one end, a spindle journaled through the disk and threaded at its upper end, a rubber covered cylinder surrounding the spindle and supported on the disk, a calibrated disk at the outer end of the cylinder, and slidably mounted therein, a cap screw threaded on the spindle and engageable with the calibrated disk to move the same into the cylinder, an indicator finger on the cap screw cooperating with the calibrated disk, a series of frictionally engaged disks on the spindle within the cylinder, some of the disks being interlocked with the cylinder and other disks interlocked with the spindle, springs interposed between the calibrated disk and the series of disks and said cap screw adapted to be adjusted for variably tensioning the friction diskswhereby a predetermined tension may be applied to a string.

ll. In the Stringing of tennis rackets, wherein a string tensioning device is adapted to have a string coiled therearound to exert a pulling force on a string threaded through a tennis racket and to be uneiective during continued movement after the string has received the desired tension, and wherein a tensioned portion of the string is held under tension while the tensioning device is being engaged with another portion of the string and wherein means is provided for holding the tensioning device against movement, a tensioning device including a handle having a disk at one end, a spindle journaled through the disk and threaded at its upper end, a rubber covered cylinder surrounding the spindle and supported on the disk, a calibrated disk at the outer end cf the cylinder, and slidably mounted therein, a cap screw threaded on the spindle and engageable with the calibrated disk to move the same into the cylinder, an indicator finger on the cap screw cooperating with the calibrated disk, a series of frictionally engaged disks on the spindle within the cylinder, some of the disks being interlocked with the cylinder and other disks interlocked with the spindle, springs interposed between the calibrated disk and the series of disks and said cap screw adapted to be adjusted for variably tensioning the friction disks wherebsr a predetermined tension may be applied to a string, a support for the tensioning device and the means for holding the tensioning device `against movement including a cam device for moving the calibrated disk and spindle to increase friction between the handle disk and support.

EDMUNDO H. SERRANO.

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