Abstract:
A tuning post for a stringed musical instrument which includes an integral string severing mechanism which automatically severs the excess length of a string while the string is being tensioned. A sharp edged aperture in the string post through which the excess string protrudes cooperates with a stationary sharp cutting edge to sever the string while the post is being turned during the initial tuning operation.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to stringed musical instruments, primarily, but not exclusively to those in the lute family. In particular, the invention concerns a new and improved tuning post for such instruments. 
     Each string of a stringed musical instrument, as for example, a guitar, is ordinarily stretched between a fixed point near the tail of the instrument, and an adjustable tuning post at the other end. The tuning post provides the necessary mechanism to adjust an the tension of the string so as to cause it to resonate at the desired frequency. As many tuning posts are required as there are strings on the instrument. 
     There are several methods in common use to fasten strings to the tuning post. According to one popular construction, when a string is installed, it is first fastened to the instrument at the tail, and then the free end is inserted through a hole in the tuning post, where it is clamped. The tuning post is then turned (usually through a worm gear drive) until the tension in the string is high enough to produce the desired note. Or, the string may be simply wrapped around the tuning post without clamping, relying on friction to keep the string from slipping. With any construction in general use, the free end of the string at this point projects out of the post, and must either be manually cut off, or left as an unsightly tail. Not only is a projecting tail unsightly, but it can be dangerous in the sense that it is common for the end of a projecting string to pierce a user&#39;s finger or to rip the lining of the instrument case. Obviously, a projecting string end should be avoided. 
     Inasmuch as string replacement may be required during the course of a performance, it is desirable that means be available to conveniently and rapidly effectuate the cutting off of excess string. It is also desirable that no tools be required. 
     Accordingly, it is an object of the present invention to provide a string cutoff mechanism which automatically severs excess string projecting from the tuning post as the post is turned to tighten the string, without requiring tools. 
     SUMMARY OF THE INVENTION 
     The foregoing object of the invention is accomplished by providing a sharp edged aperture in a rotatable string post out of which a newly installed string protrudes and also providing a sharp cutter surface which abuts the aperture. Rotating the string post causes the edge of the aperture to pass the edge of the abutting cutter surface, severing the string with a scissors-like action. Continuing to rotate the string post causes the string to be tensioned such that it vibrates at the desired frequency. 
     A more detailed explanation of the invention may be had by reference to the following detailed description, which should be read in conjuction with the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross sectional side view of a first embodiment of the present invention. The view is taken at  1 — 1  of FIG.  3 . 
     FIG. 2 is a side view 90° from the view of FIG.  1 . 
     FIG. 3 is a top view of the embodiment of FIG.  1 . 
     FIG. 4 is a cross sectional side view of a second embodiment of the invention. The view is taken at  4 — 4  of FIG.  7 . 
     FIG. 5 is a side view 90° from FIG.  4 . 
     FIG. 6 is a bottom view of the embodiment of FIG.  4 . 
     FIG. 7 is a top view of the embodiment of FIG.  4 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to a tuning post which not only allows string tension to be adjusted, as has been done in the prior art, but also automatically severs excess string when the string is initially tensioned. In accordance with a first preferred embodiment of the invention, the invented tuning post includes a conventional housing  10  which holds a worm mesh comprised of worm  11  and wormgear  12 . The worm mesh is driven by handle  13 . The housing  10  preferably includes a hole  14 , which allows the tuning post to be fastened to the instrument neck (not shown) by a screw. A screw through hole  14  will prevent the housing from rotating when the string is being tensioned. 
     A hardened cylindrical sleeve  15  is held securely to the housing  10 , as by being pinned, or otherwise held from turning. The sleeve is threaded at its free end to accept a nut  16  and washer  17 . The sleeve is inserted through a hole in the instrument neck, and the tuning post is secured to the neck by nut  16 . 
     A preferably hardened string post  18  passes through a longitudinal bore in sleeve  15 . The string post is securely fastened to wormgear  12  by, for example, pressing or brazing. A cross hole  19  is drilled through the string post at an angle, with a chamfer at the high end of the hole, tilted at an even greater angle. The end of hole  19  opposite the chamfer is sharp. The string post  18  is drilled and tapped longitudinally to receive clamp screw  22 . The top end of clamp screw  22  is preferably rounded and crosses the hole  19 . The clamp screw  22  is used to clamp the string against the top surface of hole  19 . A portion of the string post above the hole  19  is necked down in a smooth curve to define an area  21  for the string to wind. As an aid to orienting the string post when installing a string, and to indicate to the user the proper side of the string post to insert the string, a small ball  24  is attached to the top of the string post in line with the chamfer  20 . 
     As can best be seen in FIG. 2, the sleeve  15  includes a preferably angled cutter surface  23 . The cutter surface  23  is intended to cooperate with an edge of hole  19  to cut the string as the string post  18  is turned while the string is being tensioned. The cutter surface need not be angled as shown, however, with an angled surface, the cutting forces are reduced. The top surface of the sleeve  15  is low enough to not engage a string entering hole  19  through chamfer  20 . 
     When a string is installed, it is first securely attached to the instrument body at the tail, and then the free end is inserted through hole  19  from the chamfered end and pulled through. The string is clamped in the hole by turning clamp screw  22 , with the free end of the string protruding from the sharp end of the hole. Handle  13  is then rotated such that the string post turns to tension the string. As the hole  19  passes the cutter surface  23 , excess string is automatically severed, and further turning of handle  13  causes the tension in the string to be increased until it is properly tensioned. 
     FIGS. 4 through 7 illustrate a second embodiment of the invention. The tuning post of the second embodiment includes a housing  30 , worm  31 , wormgear  32 , handle  33 , and hole  34 , similar to the housing  10 , worm  11 , wormgear  12 , handle  13 , and hole  14  of the first embodiment. Instead of being held to the instrument neck by sleeve  15  and nut  16 , as in the first embodiment, a threaded bushing  35  engages threads in the neck of the housing  30 , holding the assembly in place. A washer  36  prevents the hexagonal portion of bushing  35  from marring the instrument neck during installation. 
     A preferably hardened string post  38  is securely held to wormgear  32  and passes through a bore in bushing  35 . The top of the string post is slotted with slot  39 , and a longitudinal hole  40  is drilled through so that it emerges from the bottom of the string post near the periphery. The hole, which is to serve as a passageway for a string, is preferably, but not necessarily, angled. Instead of a longitudinal hole, a longitudinal slot down the side of the string post from the slot  39  to the bottom end of the string post could also be used to serve as a string passageway. A preferably hardened cutter plate  41  is secured to the bottom of the housing  30 , as by knurling and pressing in. Cutter plate  41  includes at least one opening  42 , through which a string can pass. 
     In use, a string ( 50 ) is inserted into slot  39  and hole  40 , and the end pulled through. The handle  33  is then turned to tighten the string. As the string post is turned, the string is severed by the edge of opening  42  acting against the edge of hole  40 . Further turning of the string post tensions the string as desired.