Winding – tensioning – or guiding – Strand tensioning device – Magnet
Patent
1993-12-07
1995-10-03
Stodola, Daniel P.
Winding, tensioning, or guiding
Strand tensioning device
Magnet
2421251, 242164, 242 47, 2642905, 28240, B65H 1826, B65H 7528, D02J 122
Patent
active
054545250
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns a method for making ready-to-use ball game strings in particular for tennis racquets, whereby the string in order to be conditioned for stringing is mounted under tension on a spool where its tension is kept at least essentially constant.
2. Discussion of the Prior Art
A procedure of this kind is known from the document WO-A1-86/02850. The untreated string is taken off under tension from a supply drum braked by a defined torque and is wound at that tension, which generates an elongation in it of 5 to 15% to the length required for stringing, upon the spool.
When the string conditioned by prestressing is taken off the spool to string up in particular a tennis racquet without further delay, the hardness of the stringing drops less in time than if the string had been left unconditioned. Good results are achieved by the procedure described in the document WO-A1-86/02850.
Nevertheless it has been observed that the magnitude of prestressing carried out by the procedure of the said document WO-A1-02850 does vary over the length of the string being wound on the spool. Illustratively when starting the motion of the take-up spool, the tension will increase, and thereby the elongation of the string, over a significant time interval, from an initial zero value to a maximum; thus the tension is not constant during this time interval. Similar considerations apply to the stopping action at the end of spool winding. Moreover tensioned strings undergo creep and the string elongation is further dependent on the rate of winding. Elongation-stabilization would require winding as slowly as possible. However the start-up and stop time intervals with their uneven elongations would be lengthened thereby.
SUMMARY OF THE INVENTION
The object of the invention is to minimize the problems associated with the prior art. The invention solves the problem of creating a method of the initially cited kind in the manner defined in the claims by achieving more uniform prestressing over the entire string length than in the said known procedures.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is elucidated below in relation to the Figures which are not to scale.
FIG. 1 is a partial elevation of a spool, shown perpendicularly to the spool axis,
FIG. 2 is a spool section parallel to the spool axis,
FIG. 3 shows the detail A of the spool of FIG. 2 but in the wound state,
FIGS. 4-8 are schematics of equipment with which to carry out the method of the invention for five different operational stages of the method, and
FIG. 9 is a top view of the equipment for simultaneously conditioning two racket strings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A spool 1 (FIGS. 1 through 3) comprises a convex, circular surface 2 bounded on both sides by spool flanges 3, 4. A slot 5 to affix one of the ends of a string segment 7 to be deposited on the spool 1 is present at the spool flange 3. Also a projection 8 with an arrangement 9 used to affix the second string end is provided and will be comprehensively discussed further below. FIG. 3 furthermore shows the string segment 7 deposited in the form of a winding.
Equipment with which to carry out the method of the invention for simultaneously conditioning two strings will now be illustratively described in relation to FIGS. 4 through 9.
This equipment consists of a frame 11 with a carriage guide 12 for the horizontally displaceable adjustment of a spool carriage 13. A receiving mandrel 15 rotated by a controlled drive 14 (FIG. 9) is mounted on the carriage 13 and may receive two spools 1 simultaneously. An affixing system 16 with a pressure beam 17 and a string guide 18 is mounted next to the right end of the carriage guide 12 shown in the drawings. The equipment also includes two magazines or supply drums 20 for the untreated strings 19.
At the beginning of implementing the method of the invention, the carriage 13 assumes its right-hand end position. The equipment operator also is positioned at that end. He first slips t
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Isosport Verbundbauteile Gesellschaft m.b.H.
Mansen Michael R.
Stodola Daniel P.
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