Peg for stringed instruments

Abstract: A winding shaft (10) of a peg is composed of a base shaft portion (11) connected to a worm gear (31) and an adjustable shaft portion (12) in threaded engagement with the base shaft portion. A locking screw member (13), which can be operated from outside, is threaded into the base shaft portion (11), and the locking screw member (13) is able to apply strong pressure acting in the axial direction to the bottom surface of the adjustable shaft portion (11) after the shaft length has been adjusted. The construction enables the shaft length of the winding shaft to be adjusted to obtain a desirable angle between a string wound on the shaft and the surface of a head portion of a stringed instrument.

Description: The present invention relates to a peg for use in a stringed instrument, such as for example a guitar. A conventional peg of the foregoing type has a structure such as shown in Fig. 6, in which a knob (not shown) rotates a winding shaft 1 to wind up a string 2 thereon. A worm 4 inserted into a housing 3 is connected to the knob. The worm 4 is engaged with a worm gear 5 secured to the winding shaft 1. Therefore, when the knob is rotated, the rotational force is transmitted to the winding shaft 1 through the worm 4, thereby causing the rotation of the winding shaft. By changing the direction of rotation of the knob, the string 2 is wound up or unwound. A fixing member 6 projects from the housing 3. An appropriate number of fixing holes in the form of through holes are formed on the fixing member, so that the housing 3 is secured to a head portion 8 of the stringed instrument by fixing screws 7 inserted into the fixing holes. The above-mentioned head portion 8 has a through hole 8' through which the winding shaft 1 extends. A bush 9 is fitted into the through hole 8' to conceal the edge thereof and provide an improved appearance. The bush 9 is also adapted to prevent the winding shaft 1 from being inclined by the tension of the string. As an alternative means for securing the housing 3 to the head portion 8, there is also known a structure in which the housing 3 is provided with an externally threaded cylinder which screws into an internally threaded cylinder inserted into the through hole 8' from the top thereof, the internally threaded cylinder having a peripheral flange similar to that of the bush 9. The head portion 8 is clamped between the peripheral flange and the fixing member 6 of the housing 3 and thus the housing is secured to the head portion. US 4,827,825 discloses a tuning peg in which the string is clamped between two screws as part of the winding process. US-A-5260511 discloses the use of head machines mounted on the headstock portion of the neck, with different heights for different strings. Since the conventional peg has the winding shaft 1 formed as a single shaft body, the shaft length of the winding shaft 1 cannot be adjusted for each stringed instrument. Stringed instruments, for example, guitars, have such a structure that six strings are wound up by six pegs provided on a head portion thereof. The six pegs are so arranged that three of them are mounted on each side of the head portion or all six of them are mounted in line on one side of the head portion. In this arrangement, the strings are supported in parallel on a string support provided between the head portion and a neck portion of the stringed instrument. Since the head portion is inclined relative to the neck portion, the respective strings are strained at angles relative to a surface of the head portion between the string support and the corresponding pegs. The angles of the respective strings relative to the surface of the head portion are different from each other due to different distances between the string support and the pegs, and because the winding shafts of the pegs have the same length projecting from the surface of the head portion. The different angles of the respective strings relative to the surface of the head portion cause different pressures, i.e., different stresses to be applied to the string support by the tension forces of the strings. The largest angle between the string and the surface of the head portion is given by the string which is wound up by the peg nearest to the string support, and as the distance from the string support to the peg is increased, the angle between the string and the surface of the head portion becomes decreased. For this reason, the string wound up by the peg nearest to the string support applies the largest stress to the string support. The difference between the stresses applied by the respective strings to the string support poses the following problems. First, if the stress applied by the string to the string support is sufficiently large, the vibration energy of the string is effectively prevented by the string support from transmission to the peg. On the other hand, if the stress applied by the string to the string support is small, the vibration energy of the string is undesirably transmitted up to the peg. In this case, there arises a problem that the tone colour of the string is adversely affected by the propagation of the vibration energy of the string. Second, as the stress applied by the string to the string support is increased, the player of the stringed instrument feels a stronger tension of the string. In consequence, if stresses applied by the six strings are different from each other, the strings give a deteriorated finger-touch to the player so that there arises such a problem that the guitar is not easy to play. Further, in the case of a guitar equipped with a tremolo device, if the stresses applied by the strings to the string support are different from each other, the string which applies a larger stress to the string support exhibits a larger frictional resistance against the string support when the string picked returns to its original position, so that there arises a problem that a smooth return of the string is disturbed. The foregoing are problems posed on guitars. In other stringed instruments, for example, in five string-type bass guitars, since the 5th string is larger in diameter than the remainder of the strings, there is a demand that the stress applied by the 5th string to the string support is especially increased to prevent the attenuation of vibration energy of the 5th string. To this end, it is required to increase the angle between the 5th string and the surface of the head portion by shortening the length of the winding shaft of the peg disposed nearest to the string support such that the stress applied by the 5th string to the string support is further increased. However, conventional pegs cannot meet such requirements because the shaft length of the winding shaft thereof is constant and therefore unadjustable. According to the present invention, there is provided a peg for a stringed instrument, comprising a winding shaft composed of a base shaft portion connected to a worm gear and an adjustable shaft portion in threaded engagement with a free end of said base shaft portion, and a locking screw member capable of applying pressure in an axial direction to a bottom surface of said adjustable shaft portion, wherein said locking screw member is provided in said base shaft portion in such a manner that the locking screw member can be operated from outside. Thus, in a preferred embodiment the peg has such a structure that the winding shaft, which is rotated by a manual knob through a worm gear mechanism, is divided into a base shaft portion secured to a worm gear of the worm gear mechanism and an adjustable shaft portion fitted to the free end portion of the base shaft portion. One of the adjustable shaft portion and the base shaft portion has a female-threaded portion and the other has a male-threaded portion to be threaded into the female-threaded portion. Moreover, the foregoing adjustable shaft portion is brought into threaded engagement with the base shaft portion to permit the adjustable shaft portion to move in the axial direction relative to the base shaft portion in accordance with the length of the threaded engagement. In a preferred embodiment, the base shaft portion is provided with a locking screw member for securing the adjustable shaft portion at a required position by applying pressure to the centre of the bottom surface of the adjustable shaft portion. The locking screw member is threaded into a threaded hole formed in the central portion of the base shaft portion along the axial line. Moreover, the threaded hole is open to the outside, thereby enabling the internal locking screw member to be rotated by using a tool fittable to a tool-receiving portion of the locking screw member. When a preferred form of the peg is fitted to the head portion of a stringed instrument, the length of the winding shaft can be adjusted by changing the length of engagement between the adjustable shaft portion and the base shaft portion. After the length of the winding shaft has been adjusted as required, the locking screw member is rotated in the threaded hole to apply a pressing force to the bottom surface of the adjustable shaft portion. As a result, the threads of the female-threaded portion of the base shaft portion are brought into pressed contact with those of the male-threaded portion of the adjustable shaft portion so that frictional force is generated therebetween. Thus, both the shaft portions are fixed and unable to rotate relative to each other. The threads of the male-threaded portion and the female-threaded portion are formed in such a direction that the male-threaded and female-threaded portions are tightened against each other by the tension of the string wound on the winding shaft. For example, in a case where the tension of the string is applied to the winding shaft clockwise, the female and male threaded portions thereof have right-handed threads in such a manner that the winding shaft is tightened by the right-handed rotation of the adjustable shaft portion. Thus, in the case of a guitar of a type having six pegs disposed sequentially on one side of the head portion, six pegs are needed to have threads formed in the same direction. On the other hand, in the case of a guitar of a type having six pegs in which three pegs are provided on each side of the head portion, it is needed that three pegs fitted on one side of the head portion have threads cut in the opposite direction to that for the remaining three pegs disposed on the other side of the head portion. Certain preferred embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:- Fig. 1 is an exploded perspective view of a peg according to one embodiment of the present invention; Fig. 2 is a front view, partially in cross-section, of the peg according to the present invention, in which the peg is attached to a head portion of a stringed instrument; Fig. 3 is a front view, partially in cross-section, showing a winding shaft of the peg; Figs. 4A and 4B are cross-sectional views of the peg to assist an explanation of the operation of the peg; Fig. 5 is a vertical cross-sectional view of a peg according to another embodiment of the present invention; and Fig. 6 is a front view, partially in cross-section, of a conventional peg which is attached to a head portion of a stringed instrument. Fig. 1 is a perspective view showing a peg according to one embodiment of the present invention. A winding shaft 10 projects rotatably from a housing 20 and is arranged so as to be rotatable by a worm gear mechanism 30 accommodated in the housing, as shown in Fig. 2. The winding shaft 10 comprises a base shaft portion 11 secured to a central portion of a worm gear 31 of the worm gear mechanism 30, and an adjustable shaft portion 12 which is in threaded engagement with a free end of the base shaft portion 11 and encloses the free end. The adjustable shaft portion 12 changes the length of its threaded engagement on the base shaft portion 11 when rotated, thereby causing axial movement of the adjustable shaft portion. As shown in Fig. 3, the base shaft portion 11 has a threaded hole 111 communicating with the outside, at an end thereof nearest to the worm gear 31. In this embodiment, the threaded hole 111 communicates with the outside via a through hole 311 formed in the central portion of the worm gear 31. The base shaft portion 11 has, on the radially outer surface of the free end thereof, a male-threaded portion 112. The threaded hole 111 is axially open at the end of the male-threaded portion 112, that is, at the end of the base shaft portion 11. The adjustable shaft portion 12 has a string winding surface 121 on the radially outer surface thereof and includes a female-threaded portion 122 open at its end facing the base shaft portion 11. The female-threaded portion 122 is in threaded engagement with the male-threaded portion 112 of the base shaft portion 11. The threaded hole 111 of the base shaft portion 11 threadably receives therein a locking screw member 13. The locking screw member 13 has a flat top surface 131 and a rear surface opposite to the top surface. In the rear surface of the locking screw member, a tool receiving portion, for example, a wrench hole 132 is provided so as to open towards the worm gear 31, The locking screw member 13 is brought into threaded engagement with the threaded hole 111 in such a manner that its top surface 131 projects out of the threaded hole 111. The threaded hole 111 and the locking screw member 13 have threads formed in such a manner that the locking screw member 13 is strongly pressed onto the bottom surface of the adjustable shaft portion, that is, in this embodiment onto the inner bottom surface of the female-threaded portion 122, when a force acting in a direction in which the string is wound is applied to the locking screw member 13. The male-threaded portion 112 and the locking screw member 13 are operated in such a manner that the male-threaded portion 112 is deeply threaded into the female-threaded portion 122 to urge the adjustable shaft portion 12 towards the base shaft portion 11 when the string is wound around the adjustable shaft portion 12 and, thus, the tension of the string is applied to the winding shaft 10. Simultaneously, the locking screw member 13 is so designed that it moves into the female-threaded portion 122. Therefore, in this embodiment, if the male-threaded portion 112 and the female-threaded portion 122 have right-handed threads, the fixing screw member 13 and the threaded hole 111 have left-handed threads. Since the peg has the above-mentioned structure, the length of the winding shaft 10 can be changed by rotating the adjustable shaft portion 12 so that the position of its string winding surface 121 is shifted in the axial direction. After the shaft length has been adjusted to a required length, a wrench rod is fitted into the wrench hole 132 to rotate the locking screw member 13. Thus, its top surface 131 is brought into pressed contact with the inner bottom of the female-threaded portion 122 so that the locking screw member applies a strong pressing force to the inner bottom of the female-threaded portion 122. As shown in Fig. 4A, when the length of the shaft is adjusted, threads 122a of the female-threaded portion 122 are in contact with a lower face of each thread groove 112a of the male-threaded portion 112. On the other hand, when the locking screw member 13 is strongly pressed against the inner bottom surface of the female-threaded portion 122, the locking screw member 13 pushes the adjustable shaft portion 12 upward in such a manner that the inner bottom surface of the female-threaded portion 122 functions as the point of application of the pressing force. As a result, the threads 122a of a female-threaded portion 122 are brought into contact with an upper face of each thread groove 112a of the male-threaded portion, as shown in Fig. 4B, so that frictional force is generated therebetween. Simultaneously, threads 13a of the locking screw member 13 are also brought into contact with the lower face of each thread groove 111a of the threaded hole 111, as shown in Fig. 4B, so that frictional force is generated therebetween. Therefore, the base shaft portion 11, the adjustable shaft portion 12 and the locking screw member 13 are frictionally connected with one another by the axial pressing force exerted by the locking screw member 13 onto the adjustable shaft portion 12, so that these elements can be fixedly secured together. Further, when the axial length of the winding shaft 10 is intended to be again adjusted, the fixing screw member 13 is required to be loosened by using the wrench rod. Thus, the frictional connection between the base shaft portion 11 and the adjustable shaft portion 12 is released to enable the adjustable shaft portion 12 to be rotated freely. The peg has such a structure that the threads of the male-threaded portion 112 of the base shaft portion 11, the female-threaded portion 122 of the adjustable shaft portion 12, the locking screw member 13 and the threaded hole 111 are brought into pressure contact with each other, thereby attaining the fixing force therebetween, as shown in Figs. 4A and 4B. As described above, the peg is generally adapted such that under the tension of the string wound on to the winding shaft 10, the length of threaded engagement between the male-threaded portion 112 and the female-threaded portion 122 tends to increase and the length of threaded engagement between the locking screw member 13 and the threaded hole 111 tends to decrease, i.e., the pressing force exerted by the locking screw member 13 onto the adjustable shaft portion tends to increase in proportion to the tension of the string. However, this condition need not necessarily required as described below. That is, since the peg has such a structure that when the locking screw member 13 pushes up the adjustable shaft portion 12, strong frictional connection force is generated between the base shaft portion 11 and the adjustable shaft portion 12, if the frictional connection force attained by the locking screw member 13 is sufficiently larger than the tension force of the string which acts against the adjustable shaft, the adjustable shaft portion 12 can be effectively prevented from loosening due to the tension of the string A mounting member 21 is provided on the housing 20. The mounting member 21 is secured to a head portion 40 of the stringed instrument by fixing members such as attaching screws 22 or the like. Alternatively, the peg may have such a structure that an adjustable shaft portion 12' is threaded and inserted into a base shaft portion 11', as shown in Fig. 5. In this case, the upper portion of the threaded hole 111' is formed into a female-threaded portion 112' and the lower portion of the adjustable shaft portion 12' is formed into a male-threaded portion 122'. In general, it is so designed that the female-threaded portion 112' and the threaded hole 111' have the threads formed in the same direction such that the threads can be commonly used by the male-threaded portion 122' and a locking screw member 13. In a case where the adjustable shaft portion 12' and the locking screw member 13' are intended to be operated in opposite directions when the tension of the string is applied to the winding shaft 10, an interior of the base shaft portion 11' is divided into two areas in such a manner that the upper portion, i.e., the female-threaded portion 112', has threads formed in one direction while the lower portion, i.e., the threaded hole 111', has threads formed in the opposite direction. Since the pegs described above enable the shaft length of the winding shaft 10 to be freely adjusted as described above, there can be obtained such effects that the angles between the strings and the head portion can be uniformly adjusted by elongating the winding shaft of a peg near the string support and by shortening the winding shaft of a peg further from the string support, and thus the stress applied to the string support can be adjusted in a desirable manner. Moreover, since the same type of pegs can be used in many types of stringed instruments, inexpensive mass production and sales can be realized. Moreover, by means of the adjustable peg, the pressure applied to the string support by the strings can be controlled to an appropriate uniform value, so that the frictional resistance between each string and the string support in a case where a tremolo device is used can also be adjusted to an appropriate value, so that restoration of each string can be performed smoothly. This can provide an improved tremolo effect. Moreover, since the peg enables the adjustable shaft portion to be removed from the base shaft portion, there can be obtained further effects that the adjustable shaft portion can be replaced with that having a required structure or design even after the peg has been attached to the head portion. On the other hand, since the stresses applied by the respective strings to the string support can be individually adjusted by varying the shaft length of the winding shaft 10 of each peg, it is possible to readily meet such particular requirements as in the case of the afore-mentioned five string-type bass guitars in which it is required to adjust the stress applied by a certain string to the string support to a specific range.

Claims: A peg for a stringed instrument, comprising a winding shaft (10) composed of a base shaft portion (11,11') connected to a worm gear (31) and an adjustable shaft portion (12,12') in threaded engagement with a free end of said base shaft portion (11), and a locking screw member (13,13') capable of applying pressure in an axial direction to a bottom surface of said adjustable shaft portion (12,12'), wherein said locking screw member (13,13') is provided in said base shaft portion (11,11') in such a manner that the locking screw member (13,13') can be operated from outside. A peg as claimed in claim 1, wherein: the free end of said base shaft portion (11) is formed as a male-threaded portion (112); a female-threaded portion (122) open to face said base shaft portion (11) is formed in a central portion of said adjustable shaft portion (12); a threaded hole (111) is formed in a central portion of said base shaft portion (11); said threaded hole (111) communicates with outside through a central portion (311) of said worm gear (31); said locking screw member (13) is threaded into said threaded hole (111) in such a manner that the top surface of said locking screw member (13) projects from said male-threaded portion (112); and said locking screw member (13) has, on an end surface thereof opposite to the top surface, a tool receiving portion. A peg as claimed in claim 2, wherein said tool receiving portion is a wrench hole. A peg as claimed in claim 2 or 3, wherein said male-threaded portion (112) of said base shaft portion (11) and said female-threaded portion of said adjustable shaft portion (12) are formed with threads adapted so as to urge said adjustable shaft portion (12) towards the base shaft portion (11) when the tension of a string is applied to said winding shaft (10). A peg as claimed in claim 2 or 3, wherein said threaded hole (111) in said base shaft portion (11) and said locking screw member (13) threaded into said threaded hole (111) are formed with threads adapted such that said locking screw member (13) is guided in a direction in which it tends to project from said threaded hole (111) when the tension of a string is applied to said winding shaft (10). A peg as claimed in claim 1, wherein: a female-threaded portion (112') open to face said adjustable shaft portion (12') is formed at the free end of said base shaft portion (11'); a male-threaded portion (122') threaded into said female-threaded portion (112') of said base shaft portion (11') is formed at an end of said adjustable shaft portion (12') facing said base shaft portion (11'); a threaded hole (111') is provided adjacent to said female-threaded portion (112'), nearer to said worm gear; and a locking screw member (13') to be pressed against the bottom surface of said male-threaded portion (122') of said adjustable shaft portion (12') is disposed in said threaded hole (111'). A peg as claimed in claim 6, wherein threads of said female-threaded portion (112') of said base shaft portion (11') are formed in a direction opposite to that of threads of said threaded hole (111').

Inventors: GOTO TAKAO, GOTO, TAKAO
Applicants: GOTOH GUT YUGEN KAISHA
Application year: 1997
Main classification: G10D3
IPC codes: G10D3