Plug for electronic stringed musical instrument and cable provided with the plug

Abstract

This invention provides a plug for electronic plucked string instruments. The plug can generate sufficient threaded tightening force between the plug body and the plug cover through manual tightening, and the threaded tightening of the plug cover is not easily loosened even when external force is repeatedly applied to the cable. The plug body has: an elastic ring mounting portion formed on the outer peripheral surface of the cable mounting portion; and a body-side ring support portion, which is formed adjacent to the front side of the elastic ring mounting portion in the axial direction and has a larger diameter than the elastic ring mounting portion, restricting the forward movement of the elastic ring in the elastic ring mounting portion. A cover-side ring support portion is formed on the inner surface of the plug cover, extending radially inward relative to the axis of the main terminal portion and contacting the rear outer surface of the elastic ring mounted in the elastic ring mounting portion. The elastic ring is compressed along the axial direction between the body-side ring support portion and the cover-side ring support portion, and the front end face of the plug cover directly abuts against the rear end face of the flange.

Description

Technical Field

[0001] This invention relates to a plug for electronic plucked instruments such as electric guitars and a cable having the plug. Background Technology

[0002] Electric guitars or electric basses, among other electronic plucked string instruments, detect the waveform signal of the sound produced by string vibrations using a pickup embedded in the instrument body. This waveform signal is then sent to an amplifier via a cable extending from the instrument body for amplification, and the amplified sound is output from a speaker connected to the amplifier. In the case of typical electronic plucked string instruments, the connection between the instrument and the amplifier is formed by inserting a plug at the end of the cable into sockets located in both the instrument body and the amplifier.

[0003] Plugs for electronic plucked string instruments generally have the following structure: a metal plug body with a main terminal portion (e.g., the shape or size is specified in the specification according to the name "headphone plug") that engages with sockets on the instrument side and amplifier side, and a flange and a cable mounting portion integrally formed on the rear side; and a plug cover that covers the outer side of the cable mounting portion. The plug cover has an internal thread on its inner surface and is installed on the plug body by screwing into the external thread of the cable mounting portion.

[0004] However, unlike keyboard instruments, electronic plucked string instruments are often held and played by the player, especially during hard rock or heavy metal performances, where players sometimes swing the instrument violently. As a result, the plug connecting the cable to the instrument and amplifier is subjected to constant loads in the rotational and directional impact directions, easily causing the plug cover to loosen from the cable mounting thread or detach from the cable. If the plug cover is firmly tightened to the cable mounting with tools, this loosening is less likely. However, due to the intense load on the cable during performance, the connection between the cable mounting and the cable may sometimes break. From the perspective of making restoration easy, players tend to avoid excessively tightening the plug cover to the cable mounting.

[0005] The threads of the plug cover often loosen, and sometimes even come off. Performers habitually return it to the cable mounting area, wrap it around the hem of their clothing, or manually tighten it again. However, because it's manual tightening, it can't achieve the deep tightening of tools. Therefore, with the continuous load on the cable, the loose plug cover needs to be tightened repeatedly. From the performer's perspective, every time the plug cover loosens, it interrupts their performance, and they urgently need a fastening structure for the plug cover that prevents it from loosening even without tools.

[0006] For example, in patent document 1 Figure 9The following plug structure is disclosed: an elastic ring is embedded in the cable mounting portion adjacent to the base of the plug body; with the elastic ring compressed between the front end face of the plug cover and the base, the internal thread of the plug cover is screwed into the aforementioned external thread. In Patent Document 2... Figure 1 A similar plug structure is also disclosed in Patent Document 1. Figure 16 The following plug structure is disclosed: an elastic ring embedded in a groove adjacent to the base of the plug body is compressed by the internal thread of the plug cover, and the outer peripheral surface of the base is covered by the front end of the plug cover.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent No. 6590357

[0010] Patent Document 2: US Patent No. 6203370 Summary of the Invention

[0011] The technical problem that the invention aims to solve

[0012] In the plug structures disclosed in Patent Documents 1 and 2, the axial force that helps to tighten the internal thread of the plug cover and the external thread of the cable mounting part is mainly the restoring force in the axial direction of the elastic ring between the flange and the front end face of the plug cover, or the force of the elastic ring that has been compressed and deformed due to the internal thread. However, the elastic constant of the rubber elastic ring is extremely small compared to that of metal, and a strong thread tightening force that can sufficiently help prevent the plug cover from loosening cannot be expected. In addition, in Patent Document 1... Figure 16 In this structure, since no consideration has been given to limiting the screw's screwing stroke, there is a disadvantage that the elastic ring may become over-deformed due to excessive screwing and get stuck in the surrounding gap.

[0013] The technical problem of the present invention is to provide a plug for an electronic plucked string instrument, which can generate sufficient threaded fastening force between the plug body and the plug cover by manual tightening, and the threaded fastening state of the plug cover is not easily loosened even if external force is repeatedly applied to the cable.

[0014] Solutions for solving technical problems

[0015] This invention relates to a plug for electronic plucked instruments, used for attaching a cable to the end of a cable for connecting it to a socket of an electronic plucked instrument or amplifier. The plug, designed to solve the aforementioned technical problems, comprises: a metal plug body having a main terminal portion, a flange, and a cable mounting portion; the main terminal portion being shaped to engage with a socket on the instrument or amplifier side; the flange being integrated with the rear side of the main terminal portion when the insertion side of the main terminal portion into the socket on the instrument or amplifier side is defined as the front end side; the cable mounting portion having a smaller diameter than the flange and being integrated with the rear side of the flange, and having an external thread formed on its outer peripheral surface; the cable mounting portion being used to mount the end of a cable; and a metal plug cover having a cylindrical shape with openings at both ends in the axial direction, and having an internal thread formed on its inner peripheral surface that engages with the external thread of the cable mounting portion, and covering... The plug body includes a cable mounting portion and an elastic ring, made of a polymer elastic material, which are respectively grounded on the inner surface of the plug cover on the outer peripheral edge side and grounded on the outer surface of the cable mounting portion on the inner peripheral edge side. The plug body has an elastic ring mounting portion formed on the outer peripheral surface of the cable mounting portion; and a main body side ring support portion, which is formed adjacent to the front side of the elastic ring mounting portion in the axial direction and is larger in diameter than the elastic ring mounting portion, restricting the forward movement of the elastic ring in the elastic ring mounting portion. A cover-side ring support portion is formed on the inner surface of the plug cover, extending radially inward relative to the axis of the main terminal portion and contacting the rear outer surface of the elastic ring mounted on the elastic ring mounting portion. The elastic ring is compressed along the axial direction between the main body side ring support portion and the cover-side ring support portion. The front end face of the plug cover directly abuts against the rear end face of the flange.

[0016] In the above-described plug for an electronic plucked string instrument of the present invention, the internal thread of the plug cover is screwed into the external thread of the cable mounting portion of the plug body, such that the front end face of the plug cover abuts against the rear end face of the flange. Thus, the screwing force of the plug cover relative to the cable mounting portion is borne by the metal-to-metal contact between the plug cover and the flange, resulting in a tightening axial force between the contacting threads, governed by the elastic constant (Young's modulus) of the metal. Since the Young's modulus of the metal is much larger than the elastic constant of the elastic polymer material, a strong threaded fastening state can be formed between the plug cover and the cable mounting portion even with manual tightening. However, under the premise of insufficient manual tightening, if the plug cover rotates in the opposite direction relative to the cable mounting portion due to impact or other forces, even a small amount of rotation will cause a rapid loss of the aforementioned threaded fastening force, resulting in the plug cover loosening.

[0017] However, in the plug for an electronic plucked string instrument of the present invention, an elastic ring is provided between the plug cover and the cable mounting portion. This elastic ring is compressed along the axial direction between the main body side ring support portion and the cover side ring support portion, and the front end face of the plug cover abuts against the rear end face of the flange. Therefore, a strong threaded fastening state is formed with the metal abutting against each other, and for the following reasons, it can be effectively prevented from loosening due to external impact forces, etc.

[0018] • The axial force of the restoring force of the elastic ring, which originates from the compression deformation, overlaps with the tightening axial force of the plug cover, which restricts the screwing in by the aforementioned resistance, to form a more secure threaded fastening state.

[0019] • On the contact surfaces between the elastic ring mounting part, the main body side ring support part, and the cover side ring support part and the elastic ring, a frictional force that prevents the plug cover from rotating in the loosening direction is generated along with an axial force originating from the restoring force of the elastic ring.

[0020] The impact force applied to the plug cover is absorbed and mitigated by the elastic ring.

[0021] Therefore, it is possible to realize a plug for electronic plucked string instruments that can generate sufficient thread fastening force between the plug body and the plug cover by manual tightening, and the thread fastening state of the plug cover is not easily loosened even if external force is repeatedly applied to the cable.

[0022] In the plug for an electronic plucked string instrument of the present invention, the cover-side ring support portion can be formed as a cover-side stepped surface with a larger diameter at the front edge than at the rear edge in the axial direction. This cover-side stepped surface can be an inclined surface whose diameter gradually decreases towards the rear in the axial direction. When the cover-side stepped surface, which bears the compressive force of the elastic ring in the axial direction, is orthogonal to the axial direction, the component force pressing the elastic ring towards the elastic ring mounting portion will not cause the elastic ring to flatten in the axial direction, and the deformation generated in the direction orthogonal to the axis is constrained by the inner surface of the plug cover or the outer surface of the cable mounting portion. However, if the cover-side stepped surface is inclined as described above, even without such constraint, the component force pressing the elastic ring towards the elastic ring mounting portion will inevitably increase. Therefore, the frictional force generated on the contact surface with the elastic ring mounting portion also increases, more significantly preventing the plug cover from rotating in the loosening direction. Furthermore, by inclining the cover-side stepped surface, it is less likely to cause the elastic ring to bite into the narrow gap between the plug cover and the cable mounting portion in the axial direction, which occurs before and after the elastic ring.

[0023] When the wire diameter of the elastic ring is set to d, and the deformation of the elastic ring generated in the normal direction of the stepped surface of the cover side ring support portion when the front end face of the plug cover abuts against the rear end face of the flange is set to Δd, it is preferable to adjust the value of Δd / d to be 0.1 or more and 0.3 or less. If the value of Δd / d is less than 0.1 (10%), the elastic ring will not deform sufficiently, resulting in insufficient effect in preventing the plug cover from loosening. On the other hand, if the value of Δd / d exceeds 0.3 (30%), the deformation of the elastic ring will be too large, resulting in excessive compressive permanent deformation in the elastic polymer material constituting the elastic ring. As a result, the elastic force may not be commensurate with the amount of deformation. In addition, it may also easily lead to the elastic ring biting into the gap between the plug cover and the cable mounting portion.

[0024] In plugs for electronic plucked string instruments, a cantilever structure is often formed in the portion located further rearward than the external threaded portion of the cable mounting section. This cantilever structure has a base end that engages with the internal threaded portion of the plug housing, and a radially spaced gap is continuously formed between it and the inner surface of the plug housing. This cantilever structure results in a raised, radially spaced rear end on the inner side of the plug housing, causing repeated bending loads on the base end of the cantilever structure when tensile or torsional loads are applied to the mounted cable. These bending loads create gaps in the engagement, becoming a major cause of plug housing loosening. Therefore, in this invention, it is preferable that the elastic ring mounting portion and the elastic ring are positioned axially on the rear end of the cantilever structure. By forming an elastic ring mounting portion on the rear end side of the cantilever structure and setting the elastic ring in a way that fills the gap, even if a tensile or torsional load is applied to the installed cable, the bending displacement of the rear end side of the cantilever structure can be suppressed by the deformation resistance of the elastic ring. Furthermore, under the condition of applying an impact load, the elastic ring can also mitigate the impact. This significantly improves the effect of suppressing the gap of the screw fastening portion and thus suppressing the loosening of the plug cap.

[0025] The cable mounting section can be a structure comprising a rod and a mounting sleeve. The rod is integrally formed adjacent to the rear side of the flange, and the mounting sleeve is connected to the rear side of the rod via a connecting conductor. The mounting sleeve is formed as a cylinder with openings at both ends in the axial direction, for inserting the cable from the rear opening along the axial direction. In this case, an external thread is formed on the outer circumferential surface of the rod, while an internal thread is formed on the front end of the inner surface of the plug cover. This structure, except that the front end face of the plug cover directly abuts against the flange, is essentially a continuation of the structure of a typical electronic plucked instrument plug. Furthermore, a spring ring mounting portion and a spring ring can be provided in at least one of the rod and the mounting sleeve. Therefore, the structure unique to this invention can be reasonably assembled without significantly altering the structure of a typical electronic plucked instrument plug.

[0026] In this configuration, since the connecting conductor can form the aforementioned cantilever structure together with the mounting sleeve, it is preferable, from the viewpoint of improving the effect of suppressing plug cap loosening, to provide at least the elastic ring mounting portion and the elastic ring on the mounting sleeve side. In particular, when the connecting conductor has a smaller axial cross-sectional area than the mounting sleeve, the bending stiffness of the cantilever structure decreases at the location of the connecting conductor, resulting in a larger bending displacement of the cantilever structure even under relatively small loads on the cable, making plug cap loosening more likely. Therefore, in this configuration, the effect of providing the elastic ring mounting portion and the elastic ring on the mounting sleeve side is more significant.

[0027] Here, when the elastic ring mounting portion is formed on the rod portion, the outer diameter of the elastic ring mounting portion is easily constrained by the nominal diameter of the external thread portion in the relationship where the rod portion with the external thread portion needs to be screwed into the internal thread portion on the plug cover side. Therefore, there is a problem that it is slightly difficult to sufficiently ensure the deformation absorption space of the elastic ring formed on the outer peripheral edge side of the elastic ring. In contrast, for the mounting sleeve without the external thread portion, since there is no background of such constraint, it has the advantage of easily ensuring the deformation absorption space of the elastic ring. In this case, the elastic ring mounting portion and the elastic ring can of course be provided on both the rod portion and the mounting sleeve, but by ensuring that the deformation amount of the elastic ring on the mounting sleeve side is sufficiently large, the elastic ring on the rod portion side can be omitted. That is, even if only the elastic ring mounting portion and the elastic ring are provided in the form of the mounting sleeve, the effect of preventing the plug cover from loosening can be achieved without any problems. Thus, the installation position of the elastic ring mounting portion and the elastic ring is only one, which helps to simplify the structure of the electronic plucked string instrument plug of the present invention.

[0028] The effects of the invention

[0029] Details regarding the function and effects of this invention have already been described in the "Solutions for Solving Technical Problems" section, and therefore will not be repeated here. Attached Figure Description

[0030] Figure 1 This diagram illustrates the state in which an electric guitar is connected to an amplifier via an electronic plucked instrument plug according to an embodiment of the present invention.

[0031] Figure 2 This is a front view and a front cross-sectional view of an electronic plucked string instrument plug according to an embodiment of the present invention.

[0032] Figure 3 It is Figure 2 The front view, side view, and bottom view of the plug body of the electronic plucked string instrument are shown.

[0033] Figure 4yes Figure 3 A side cross-sectional view of the plug body.

[0034] Figure 5 This is shown with the cables installed. Figure 3 An enlarged front view of the cable installation section.

[0035] Figure 6 yes Figure 5 EE cross-sectional view.

[0036] Figure 7 The elastic ring is shown in two states: uncompressed (left) and compressed (right). Figure 2 Enlarged front view cross section of the periphery of the elastic ring.

[0037] Figure 8 This is an enlarged view of the knurled part formed on the plug cover.

[0038] Figure 9 This is a diagram showing how a plug cover is installed on a cable with a plug for an electronic plucked string instrument.

[0039] Figure 10 This is an illustrative diagram showing the deformation process that occurs on the elastic ring when the plug cover is installed on the plug body.

[0040] Figure 11 It is a graph showing the relationship between the amount of compression in the axial direction of the elastic ring and the resulting elastic stress.

[0041] Figure 12 It is a graph showing the relationship between the thread rotation angle and the thread axial force.

[0042] Figure 13 It is shown Figure 2 A graph showing the relationship between the thread rotation angle of the plug cover in an electronic plucked string instrument plug and the axial force, thread axial force, and total axial force generated on the elastic ring.

[0043] Figure 14 This is an enlarged front cross-sectional view showing a modified example in which the elastic ring mounting part is provided on the rod.

[0044] Figure 15 This is an enlarged front cross-sectional view showing the function of the raised section and the recessed section.

[0045] Figure 16 This is an enlarged side cross-sectional view showing the function of the raised section and the recessed section.

[0046] Figure 17 yes Figure 6 The diagram illustrates the function of the DD section. Detailed Implementation

[0047] Figure 1 This illustration shows the state in which an electric guitar 100, an electronic stringed instrument, is connected to an amplifier via an electronic stringed instrument plug 1 according to an embodiment of the present invention. The electronic stringed instrument plug 1 is connected to the front end of a cable 50. An instrument-side socket 101, forming a sound output terminal, is formed on the lower part of the main body surface of the electric guitar 100 (or possibly the lower side surface). The cable 50 is connected by inserting the plug 1 into the instrument-side socket 101. An amplifier-side socket 111 is formed on the amplifier 110. The cable 50 is connected by inserting the other end of the plug 1 into the amplifier-side socket 111. The plug 1 can be provided at both ends of the cable 50. Hereinafter, the plug 1 inserted into the instrument-side socket 101 will be described as an example, but the plug 1 inserted into the amplifier-side socket 111 is also the same. It should be noted that the electronic stringed instrument to which this invention is applied is not limited to an electric guitar, but can also be other types of stringed instruments such as an electric bass or an electric shamisen.

[0048] Figure 2 The plug 1 is shown in magnified view. The plug 1 has a metal plug body 8 and a plug cover 30. The plug body 8 has a main terminal portion 9. The main terminal portion 9 is formed, for example, into a known headphone plug with a shape specified by JIS: C6560 (1994), and has a shape that engages with the instrument-side socket 101. Hereinafter, in the axial direction (O) of the main terminal portion 9, the insertion side of the main terminal portion 9 toward the instrument-side socket is defined as the front end side.

[0049] The plug body 8 includes a flange 12 integrated with the rear side of the main terminal portion 9 and a cable mounting portion 7. The cable mounting portion 7 is integrated with the rear side of the flange 12 in a manner smaller than the diameter of the flange 12, and has an external thread portion 13 formed on its outer peripheral surface, and the end of the cable 50 is mounted thereon. In addition, the plug cover 30 is a cylindrical shape with openings at both ends in the axial direction, and has an internal thread portion 31 formed on its inner peripheral surface that engages with the external thread portion 13 of the cable mounting portion 7, so that the cable 50 extends from the rear opening and covers the cable mounting portion 7. The dimensions of each part of the plug 1 are not particularly limited, for example, the overall length is 60 mm, the outer diameter of the main terminal portion 9 is 6.3 mm, and the axial length is 30.5 mm.

[0050] An elastic ring 40 is provided between the cable mounting part 7 and the plug cover 30. The elastic ring 40 is made of a high-molecular elastic material such as rubber or elastomer (natural rubber in this embodiment), and is grounded to the inner surface of the plug cover 30 on the outer peripheral edge side and to the outer surface of the cable mounting part 7 on the inner peripheral edge side.

[0051] On the plug body 8, an elastic ring mounting portion 16g is formed on the outer peripheral surface of the cable mounting portion 7. Additionally, a body-side ring support portion 16j is formed adjacent to the front side of the elastic ring mounting portion 16g in the axial direction. The body-side ring support portion 16j is formed to be larger than the diameter of the elastic ring mounting portion 16g in the direction of axis O, thus restricting the movement of the elastic ring mounting portion 16g towards the front side of the elastic ring 40. On the other hand, a cover-side ring support portion is formed on the inner surface of the plug cover 30. The cover-side ring support portion is formed to extend radially inward relative to the axis O of the main terminal portion 9 at a position where it contacts the rear outer surface of the elastic ring 40 mounted on the elastic ring mounting portion 16g, and contacts the elastic ring 40.

[0052] like Figure 3 As shown, the cable mounting part 7 includes a rod 4s, a connecting conductor 14, and a mounting sleeve 16. The rod 4s is integrally formed adjacent to the rear side of the flange 12. In addition, the mounting sleeve 16 is connected to the rear side of the rod 4s via the connecting conductor 14, and is formed into a cylindrical shape with openings at both ends in the direction of the axis O.

[0053] like Figure 4 As shown, the main terminal portion 9 is composed of a rod-shaped main metal fitting 3 and a front portion of a grounding metal fitting 4 disposed outside the main metal fitting 3, separated by a plug-side insulating layer 5 (a flange 12 and a cable mounting portion 7 are formed on the rear portion of the grounding metal fitting 4). The front end portion 3t of the main metal fitting 3 has a engaging recess 3c on its side for engaging with a musical instrument-side socket, and a terminal flange portion 3f is integrally formed behind the engaging recess 3c in the direction of the axis O. On the other hand, the grounding metal fitting 4 is formed into a cylindrical shape, and the main metal fitting 3 is inserted from the rear end from its front end opening along the direction of the axis O in the form of clamping the cylindrical plug-side insulating layer 5. An insulating flange 5f formed on the front end portion of the cylindrical plug-side insulating layer 5 is clamped between the rear end face of the terminal flange portion 3f of the main metal fitting 3 and the front end face of the grounding metal fitting 4. The plug-side insulating layer 5 is formed as an injection-molded body of a self-lubricating resin, such as polyacetal resin.

[0054] Specifically, the main metal fitting 3 and the grounding metal fitting 4 are made of copper alloys such as brass, phosphor bronze, or beryllium copper, and are plated on the surface to prevent corrosion or improve conductivity. Specifically, the plating is a nickel plating layer, a chromium plating layer, etc., and to further improve conductivity, gold plating can also be applied to the outermost layer. The rod 4s, connecting conductor 14, and mounting sleeve 16 of the grounding metal fitting 4 are integrally formed by machining the metal rod. To prevent the fixing screw 17 from loosening, the higher the rigidity of the mounting sleeve 16, the better. From this point of view, the grounding metal fitting 4 is preferably made of phosphor bronze or beryllium copper with high tensile strength. Beryllium copper has particularly high strength, which is more advantageous from the viewpoint of preventing the fixing screw 17 from loosening. However, since it is a precipitation-hardening alloy, the necessary rigidity can be ensured by machining the material in a solution-treated state followed by precipitation-strengthening heat treatment.

[0055] A rod portion 4s, larger in diameter than the main terminal portion 9, is formed on the grounding metal fitting 4. The flange 12 is integrated with the front end of the rod portion 4s. A countersunk hole 4c is formed on the rear end face of the rod portion 4s. The rear end of the main metal fitting 3, inserted into the inner side, protrudes into the countersunk hole 4c along with the plug-side insulating layer 5, and is fixed by an insulating ring 6 (made of heat-resistant resin such as phenolic resin) embedded in the countersunk hole 4c. Furthermore, the rear end of the main metal fitting 3 protrudes rearward from the insulating ring 6, and a ring-shaped terminal metal fitting 10 is inserted into its outer side in a conductive manner. A semi-cylindrical solder receiving portion 10a is integrated with the rear end face of the terminal metal fitting 10 in a protruding manner. A core wire insertion hole 3b is formed at the opening on the rear end face of the main metal fitting 3. The connecting conductor 14 is a semi-cylindrical shape that is open on one side relative to the axis O of the plug 1. It is formed by flat cuts on both sides of the outer side of the rear end side (the side that engages with the mounting sleeve 16) to form a pair of welding surfaces 15, 15.

[0056] Figure 5 This is shown with cable 50 installed. Figure 3 Enlarged front view of cable mounting section 7 Figure 6 yes Figure 5 EE cross-sectional view. (e.g.) Figure 6 As shown, inside the mounting sleeve 16, the front end of the cable 50 is inserted along the axial direction from the rear end opening and secured by a fixing screw 17. The fixing screw 17 is screwed into the peripheral wall of the mounting sleeve 16 in such a way that it penetrates the peripheral wall in the radial direction and its front end face abuts against the insulating outer sheath 51 of the cable 50. The cable 50 is held in place by the screwing compression force between itself and the peripheral wall.

[0057] The cable 50 is configured as a coaxial shielded cable with shielding conductor layers 52 and 53 inside the insulating outer sheath 51, and a core wire 55 disposed inside the shielding conductor layers 52 and 53, separated by an intermediate insulating layer 54. In this embodiment, the shielding conductor layers 52 and 53 are composed of a first layer 52 and a second layer 53, both of which are formed as winding portions with conductors tightly wound around the outside of the intermediate insulating layer 54. The winding directions of the conductors in the first layer 52 and the second layer 53 are opposite to each other, which improves the electrostatic shielding effect on the core wire 55 through which the musical signal current flows.

[0058] The insulation sheath 51 of the cable 50 is stripped from the front end to expose the shielding conductor layers 52 and 53, and the front end of the intermediate insulation layer 54 is similarly stripped to expose the core wire 55. This is achieved through the core wire insertion hole 3b on the rear end face of the main metal fitting 3. Figure 5 The core wire 55 is inserted into the plug 1, and molten solder flows into the gap between the front end face of the intermediate insulation layer 54 and the rear end face of the terminal metal fitting 10, thereby forming a solder joint 56 that connects the core wire 55 and the terminal metal fitting 10. This soldering is performed with the plug 1 horizontally positioned with the open side of the connecting conductor 14 facing upwards. The solder receiving part 10a serves to prevent molten solder from falling and to increase the soldering area. On the other hand, the exposed shielding conductor layers 52 and 53 are led out in a manner where the front ends of the windings of the first layer 52 and the second layer 53 are separated to the left and right, and are joined to the corresponding soldering surfaces 15 and 15 by solder joints 57 and 58, respectively.

[0059] Return to Figure 2 An external thread 13 is formed on the outer peripheral surface of the rod portion 4s. An internal thread 31 is formed on the front end of the inner surface of the plug cover 30. An elastic ring mounting portion 16g and an elastic ring 40 are disposed on the mounting sleeve 16. The rear end of the mounting sleeve 16 in the direction of the axis O is a reduced-diameter portion 16e, which is formed by a stepped surface on the sleeve side. This stepped surface on the sleeve side forms a main body side ring support portion 16j (hereinafter also referred to as the sleeve side stepped surface 16j). An elastic ring mounting portion 16g is formed on the outer peripheral surface of the reduced-diameter portion 16e. The plug cover 30 is fixed to the plug 1 by screwing the internal thread 31 formed on the inner peripheral surface of its front end onto the external thread 13 on the plug 1 side, thereby abutting the flange 12 at its front end edge.

[0060] Figure 7 The diagram illustrates two states of the elastic ring 40: an uncompressed state (left) and a compressed state (right: the state in which the plug cover 30 abuts against the flange 12). Figure 2An enlarged front cross-sectional view of the periphery of the elastic ring 40. The elastic ring 40 is compressed along the axial direction between the main body side ring support 16j and the cover side ring support, and in this state, the front end face 30t of the plug cover 30 directly abuts against the rear end face 12s of the flange 12. The cover side ring support is formed as a cover side stepped surface (hereinafter also referred to as a cover side stepped surface) with a larger diameter at the front end edge than at the rear end edge in the axial direction. The cover side stepped surface is an inclined surface whose diameter gradually decreases towards the rearward side in the direction of the axis O. The cover side stepped surface is formed as a conical surface, but it can also be formed as a curved surface.

[0061] The inner circumferential surface 32a of the plug cover 30, which connects to the front edge of the stepped surface on the cover side, and the inner circumferential surface 32b of the plug cover 30, which connects to the rear edge of the stepped surface on the cover side, are both cylindrical. A gap g1 is formed between the main body 16m of the mounting sleeve 16 and the inner circumferential surface 32a of the plug cover 30, and a gap g2 is formed between the reduced diameter portion 16e and the inner circumferential surface 32b of the plug cover 30. The dimensions of gaps g1 and g2 are, for example, 0.1 mm or more and 0.5 mm or less. Furthermore, when using... Figure 7 With the plug cover 30 on the right side abutting against the flange 12, the distance h from the stepped surface 16j on the sleeve side to the leading edge edge of the stepped surface on the cover side is, for example, 0.3 mm or more and 0.8 mm or less (in... Figure 7 (The middle part is 0.5mm).

[0062] The elastic ring mounting portion 16g is formed in a groove shape by receiving the inner peripheral edge of the elastic ring 40, causing the outer peripheral edge of the elastic ring 40 to offset radially inward from the inner surface of the plug cover 30. The elastic ring 40 is formed as a so-called O-ring, such as... Figure 7 As shown, in including Figure 2 The inner edge shape of the elastic ring mounting part 16g on the cross section of the axis O is an arc shape corresponding to the cross section of the elastic ring 40.

[0063] The outer diameter of the elastic ring 40 is set such that, in Figure 7 In the uncompressed state on the left side, a gap g0 is generated between the inner circumferential surfaces connected to the leading edge of the stepped surface on the cover side of the plug cover 30. The gap g0 is, for example, 0.05 mm or more and 0.3 mm or less. Figure 7 (The inner diameter is 0.1 mm). In addition, the inner diameter of the elastic ring 40 is, for example, 7 mm or more and 10 mm or less (8 mm in this embodiment).

[0064] like Figure 7 As shown on the right, the wire diameter of the elastic ring 40 is set such that it forms a compressed state in the radial direction inward through the inner circumferential surface connected to the front edge of the stepped surface on the cover side of the plug cover 30. The wire diameter of the elastic ring 40 is, for example, 1.0 mm or more and 2.0 mm or less (1.5 mm in this embodiment).

[0065] Furthermore, when the wire diameter of the elastic ring 40 is set to d, and the deformation of the elastic ring 40 generated in the normal direction of the stepped surface of the cover-side ring support portion is set to Δd when the front end face of the plug cover 30 abuts against the rear end face of the flange 12, the value of Δd / d (hereinafter referred to as the "compression amount" of the elastic ring 40) is adjusted to be 0.1 or more and 0.3 or less. Figure 7 In the state on the right, the value of the above compression is approximately 0.2.

[0066] On the outer periphery of the elastic ring 40, in the axial direction, a deformation-absorbing space A is formed, surrounded by the inner periphery surface 32a of the front side of the plug cover 30, the sleeve-side stepped surface 16j, the cover-side stepped surface 32j, and the outer surface of the elastic ring 40. Additionally, on the outer periphery of the elastic ring 40, in the axial direction, in the rearward direction (the reduced diameter side of the inclined cover-side stepped surface 32j), a deformation-absorbing space A' is also formed, surrounded by the inner periphery surface 32b of the rearward side of the plug cover 30, the outer periphery surface of the reduced diameter portion 16e, and the outer surface of the elastic ring 40. The deformation-absorbing space A is larger in volume than the deformation-absorbing space A'. These deformation-absorbing spaces A and A' function as deformation-absorbing spaces of the elastic ring 40.

[0067] Return to Figure 2 Knurled portions 4r, 30r1 to 30r3 are respectively engraved on the outer peripheral surface of the flange 12 of the plug 1 and the outer peripheral surface of the plug cover 30. Figure 8 The knurled portions 30r1 to 30r3 of the plug cover 30 are shown in magnification. A circumferential valley-shaped portion 30c is formed at the midpoint of the axial direction on the outer peripheral surface of the plug cover 30, and a pair of circumferential first ribs 30b1 and 30b3 are formed adjacent to the two sides of the valley-shaped portion 30c in the axial direction. On the other hand, a second rib 30b2 is formed at the bottom of the valley-shaped portion 30c, and the top surface of the second rib 30b2 is offset further towards the valley bottom (inward direction of the radius of the plug cover 30) than the top surfaces of the first ribs 30b1 and 30b3.

[0068] Since the top surface of the second rib 30b2 is offset from that of the first ribs 30b1 and 30b3, the knurled portions 30r1 and 30r3 of the first ribs 30b1 and 30b3 and the knurled portion 30r2 of the second rib 30b2 are respectively engraved separately by a first rolling die (not shown) and a second rolling die (not shown).

[0069] The following is a detailed description of the usage, function, and effects of the electronic plucked string instrument plug 1 of the present invention. Figure 9As shown, the cable 50 is passed through the inside of the plug cover 30 and connected to the cable mounting portion 7 of the plug body 8 in the manner described. In this state, the internal thread portion 31 of the plug cover 30 is screwed into the external thread portion 13 of the cable mounting portion 7 of the plug body 8, so that the front end face of the plug cover 30 abuts against the rear end face of the flange 12.

[0070] Figure 10 The diagram illustrates the deformation process on the elastic ring 40 when the plug cover 30 is installed on the plug body 8. S1 represents the initial screw-in state when the stepped surface 32j on the cover side begins to contact the elastic ring 40, during which the elastic ring 40 does not deform. S2 represents the state where the plug cover 30 screws in only a distance td1 from the state of S1. The elastic ring 40 undergoes compressive deformation in the axial direction corresponding to the aforementioned screw-in distance td1, passing through the inclined stepped surface 32j on the cover side. In the figure, the dashed line represents the outer diameter of the elastic ring 40 before deformation. Because a gap g0 is formed between the front inner circumferential surface 32a and the elastic ring 40, a bulging displacement occurs on the elastic ring 40 in a direction orthogonal to the axis (approaching the front inner circumferential surface 32a).

[0071] S3 indicates that the screw-in distance of the plug cover 30 has increased to the state of td2 (at this moment, the front end face 30t of the plug cover 30 has not touched the rear end face 12s of the flange 12). The bulging deformation of the elastic ring 40 in the direction orthogonal to the axis is restricted by the front inner circumferential surface 32a, and the amount of elastic deformation develops into the deformation absorption space A. The amount of deformation of the elastic ring 40 also develops into the deformation absorption space A', but the gap g2 connecting the rear side of the deformation absorption space A' is narrow, and the resistance to the amount of deformation of the elastic ring 40 entering this place is large. Therefore, the volume of the deformation absorption space A' is small, and the filling ends prematurely in the initial stage. Therefore, the subsequent deformation of the elastic ring 40 is mainly absorbed by the deformation absorption space A. Furthermore, as the filling of the deformation-absorbing spaces A and A' proceeds, the contact area between the elastic ring 40 and the plug cover 30 or the mounting sleeve 16, and the volume area of ​​the elastic ring 40 constrained by contact friction, increases, the deformation resistance of the elastic ring 40 increases, and as a result, the increase in the axial force of the thread fastening also increases with the increase in the amount of deformation of the elastic ring 40.

[0072] s4 indicates the state where the front end face 30t of the plug cover 30 begins to contact the rear end face 12s of the flange 12. Preferably, the wire diameter of the elastic ring 40 is set such that the deformation of the elastic ring 40 in this stage precisely fills the deformation absorption spaces A and A', especially the deformation absorption space A (e.g., more than 50% and less than 100%). s5 indicates the state where the plug cover 30 is further rotated and tightened after the front end face 30t of the plug cover 30 contacts the rear end face 12s of the flange 12. In the stage up to s4, the axial force generated between the internal thread portion 31 and the external thread portion 13 is supported by the elastic restoring force of the elastic ring 40, and the rate of increase of the axial force corresponding to the thread rotation angle is also governed by the elastic constant of the elastic polymer material constituting the elastic ring 40. However, in the thread rotation range from s4 to s5, since the axial force mentioned above is supported by the elastic restoring force of the intermetallic fastening originating from the plug cover 30 and flange 12 (as well as the internal thread portion 31 and external thread portion 13), the axial force increase rate corresponding to the thread rotation angle increases sharply in the form of being dominated by the Young's modulus of the metal.

[0073] Figure 11 This is a graph showing the relationship between the amount of compression in the axial direction of the elastic ring 40 and the resulting elastic stress. Up to the compression value used in this embodiment (0.2 = 20%), the elastic stress increases substantially linearly, remaining at a level of 1 to several MPa. On the other hand, Figure 12 This is a graph showing the relationship between the thread rotation angle and the thread axial force under the premise of metal-to-metal fastening. For example... Figure 7 As shown, a gap typically exists between the internal thread portion 31 and the external thread portion 13. Even when the plug cover 30 contacts the flange 12, the thread axial force hardly increases even with an increase in the thread rotation angle until the gap is filled. However, after the gap is filled, the intermetallic fastening begins to develop, and the thread axial force begins to increase. When the finishing of the contact surfaces between the plug cover 30 and the flange 12, and between the internal thread portion 31 and the external thread portion 13, is performed using a cutting surface such as a lathe, a transition zone is generated in the initial stage of the increase in the thread rotation angle. This transition zone is dominated by deformation actions of the metal surface portion, such as pressing and flattening, due to machining irregularities. The increase in thread axial force in this transition zone is relatively slow. Furthermore, if the intermetallic adhesion reaches a sufficient level, the transition zone ends, becoming the elastic deformation zone of the metal block. In this zone, the thread axial force increases linearly and rapidly with only a slight increase in the rotation angle, following the gradient of Young's modulus. The starting point of this elastic deformation zone is called the inflection point. It can be seen that even in the transition range, the thread axial force obtained by increasing the rotation angle by a small amount of about 10° will reach [a certain value]. Figure 11 The stress generated by the elastic ring 40 at a compression of 20% is 5 to 10 times that shown.

[0074] based on Figure 11 and Figure 12 Data about Figure 2 The electronic plucked string instrument plug 1 of the present invention, in Figure 13 The diagram shows a graph simulating the relationship between the thread rotation angle of the plug cover 30 and the axial force generated on the elastic ring 40 (diamond mark and dashed line), the thread axial force (triangle mark and dashed line), and the total axial force (circle mark and solid line). Figure 10 During the process from s2 to s4, the axial force generated on the elastic ring 40 is dominant, and at the moment of s4, an axial force of less than 2 MPa is generated. This value is too small for preventing thread loosening alone, but importantly, it applies a tightening force to the thread without the assistance of the elastic ring 40, that is, when tightening is performed solely by the thread. Figure 13 The single-dot dashed line will never generate a bias axial force. In addition, at s4→s5, which is supported by the elastic restoring force originating from the intermetallic fastening, the axial force of the threaded fastening increases to several times the aforementioned bias axial force, forming a firm fastening state.

[0075] Here, the screwing of the plug cover 30 into the plug body 8 is done manually, making it difficult to increase the tightening to a level equivalent to... Figure 12 The axial force at the turning point is approximately 50 MPa. Conversely, if tools are used to tighten beyond the turning point, loosening is not likely, but without tools, the tightening is difficult to loosen. Therefore, in this embodiment, it can be said that the dimensions of each part are adjusted by manual tightening to keep the threaded tightening state within the transition range.

[0076] The advantages of the above structure are as follows. Specifically, the screwing force of the plug cover 30 relative to the cable mounting portion 7 is borne by the metal-to-metal contact between the plug cover 30 and the flange 12. Therefore, a tightening axial force governed by the elastic constant (Young's modulus) of the metal is generated between the contacting threads. Since the Young's modulus of the metal is much larger than the elastic constant of the elastic polymer material, a strong threaded fastening state can be formed between the plug cover 30 and the cable mounting portion 7 even with manual tightening. However, under the premise of insufficient manual tightening, if the plug cover 30 rotates in the opposite direction relative to the cable mounting portion 7 due to impact forces, etc., then as observed... Figure 13 The s5→s4 range of the thread axial force curve (single-dot dashed line) also clearly shows that even a small amount of rotation will cause the thread tightening force to be lost sharply, resulting in the plug cover 30 becoming loose.

[0077] However, in the plug 1 for electronic plucked string instruments, an elastic ring 40 is provided between the plug cover 30 and the cable mounting part 7. This elastic ring 40 is compressed along the axial direction between the main body side ring support part 16j and the cover side ring support part, and the front end face of the plug cover 30 abuts against the rear end face of the flange 12. Therefore, a strong threaded fastening state is formed with the metal abutting against each other, and for the following reasons, it can effectively prevent loosening due to external impact forces, etc.

[0078] ·Compare Figure 13 The thread axial force curve (single-dot dashed line) and the full axial force curve (solid line) clearly show that the axial force originating from the restoring force of the elastic ring 40 due to compression deformation overlaps with the axial force originating from the intermetallic fastening that restricts the screwing of the plug cover 30 by resisting, forming a more robust threaded fastening state.

[0079] • On the contact surfaces of the elastic ring mounting part 16g, the main body side ring support part 16j and the cover side ring support part with the elastic ring 40, the frictional force that prevents the plug cover 30 from rotating in the loosening direction is generated along with the axial force originating from the restoring force of the elastic ring 40, thus preventing the plug cover 30 from returning in the loosening direction.

[0080] The impact force applied to the plug cover 30 is absorbed and mitigated by the elastic ring 40.

[0081] Therefore, it can be said that an electronic plucked string instrument plug 1 has been realized, which can generate sufficient thread fastening force between the plug body 8 and the plug cover 30 by manual tightening, and the thread fastening state of the plug cover 30 is not easy to loosen even if external force is repeatedly applied to the cable 50.

[0082] Here, with an excessive wire diameter in the elastic ring 40, it is difficult to make the plug cover 30 abut against the flange 12. For example... Figure 13 As shown by curve LR, if the elastic ring 40 is propelled by compression deformation, then before the plug cover 30 touches the flange 12, Figure 7 The deformation absorption spaces A and A' are completely filled. At this moment, the elastic ring 40 becomes nearly sealed through the deformation absorption spaces A and A'. During the stage of small thread rotation, the axial force increase rate increases significantly. Therefore, until it reaches the flange 12, the plug cover 30 cannot be tightened manually. If the plug cover 30 does not abut against the flange 12, as mentioned in Patent Documents 1 and 2, the thread tightening is insufficient and cannot help prevent the plug cover 30 from loosening. Furthermore, if the plug cover 30 is forcibly abutted against the flange 12, then... Figure 7 It is difficult to avoid the elastic ring 40 biting into the gaps g1 and g2.

[0083] In addition, Figure 2Alternatively, a structure can be adopted in which the stepped surface 32j on the side of the cover is orthogonal to the axial direction. However, the component force pressing the elastic ring 40 towards the elastic ring mounting part 16g will not cause the elastic ring 40 to be flattened in the axial direction. The deformation generated in the direction orthogonal to the axis is constrained by the inner surface of the plug cover 30 or the outer surface of the cable mounting part 7. However, as Figure 7 As shown, if the stepped surface 32j on the cover side is inclined, the component force PF pressing the elastic ring 40 against the elastic ring mounting portion 16g will inevitably increase even without the aforementioned constraint. Therefore, the frictional force generated on the contact surface with the elastic ring mounting portion 16g also increases, more significantly preventing the plug cover 30 from rotating in the loosening direction. Furthermore, by inclining the stepped surface 32j on the cover side, it is less likely that the elastic ring 40 will bite into the narrow gaps g1 and g2 between the plug cover 30 and the cable mounting portion 7 generated in the axial direction before and after the elastic ring 40. If the elastic ring is compressed and deformed relative to the inner surface of the plug cover 30 or the outer surface of the cable mounting portion 7 with a certain stress and is pressed, the sliding displacement relative to the contact surface is constrained by friction. As a result, the portion from the contact surface to a certain depth becomes a rigid dead portion. If the stepped surface 32j on the cover side is inclined, the component force PF pressing against the elastic ring mounting portion 16g increases, and the dead portion formed on the contact surface side with the elastic ring mounting portion 16g expands. As such, the increase in dead material reduces the elastic deformation area flowing into gaps g1 and g2, which is presumed to be the main reason why it is difficult for the elastic ring 40 to engage. It should be noted that the increase in dead material increases the apparent elastic constant of the elastic ring 40 as a whole, and therefore also helps to increase the screw-on fastening force of the plug cover 30 before it abuts against the flange 12.

[0084] like Figure 7 As shown, by forming the elastic ring mounting portion 16g into a groove shape, the increase in the inner diameter of the plug cover 30 can be suppressed, and an elastic ring 40 with a larger wire diameter can be used. This increases the amount of deformation of the elastic ring 40 when the plug cover 30 is abutting against the flange 12. Furthermore, by using the groove-shaped elastic ring mounting portion 16g, the contact area between the elastic ring 40 and the elastic ring mounting portion 16g is also increased. Therefore, the effect of preventing the plug cover 30 from rotating in the loosening direction, and thus the effect of preventing the plug cover 30 from loosening, is further enhanced. It should be noted that the cross-sectional shape of the elastic ring mounting portion 16g can also be simply rectangular.

[0085] Furthermore, by forming the gap g0, the deformation absorption zone A can expand towards the outer peripheral edge of the elastic ring 40, allowing the compressive deformation of the elastic ring 40, which helps prevent the plug cover 30 from loosening, to develop more smoothly in the axial direction. Moreover, since the diameter of the elastic ring 40 is set such that, before the front end face of the plug cover 30 abuts against the rear end face of the flange 12, it forms a compressed state in the radial direction through the inner peripheral surface connected to the front edge of the stepped surface of the plug cover 30, the following effect is also produced: The bulging deformation of the elastic ring 40 generated in the direction orthogonal to the axis is constrained by the inner peripheral surface of the plug cover 30 after it has advanced to fill the gap g0. Therefore, the resistance to the development of the deformation of the elastic ring 40 towards the surrounding deformation absorption spaces A, A' increases, and the increase in the axial force of the screwing until the plug cover 30 abuts against the flange 12 becomes more significant. This also helps to make the effect of preventing the plug cover 30 from loosening more significant.

[0086] Furthermore, the portion of the cable mounting part 7 located further rearward than the external thread part 13 forms a cantilever structure. This cantilever structure, with its base end at the threaded fastening portion of the plug cover 30's internal thread part 31, forms a continuous radial gap between itself and the inner surface of the plug cover 30. Specifically, the cantilever structure is formed by connecting the conductor 14 and the mounting sleeve 16. This cantilever structure is so called that the rear end side of the plug cover 30 is raised radially with a gap on the inner side, thus... Figure 9 As shown, when tensile or torsional loads are applied to the installed cable 50, the cantilever bending load repeatedly acts on the screw fastener at the base. This bending load creates gaps in the screw fastener, which is the main cause of the plug cover 30 loosening.

[0087] exist Figure 2 In this structure, the elastic ring mounting portion 16g and the elastic ring 40 are disposed on the mounting sleeve 16, that is, on the rear end side of the cantilever structure portion in the direction of axis O. With this configuration, even for… Figure 9 When the cable is subjected to tensile or torsional loads, the bending displacement at the rear end of the cantilever structure can be suppressed by the deformation resistance of the elastic ring 40. Furthermore, under impact loads, the elastic ring 40 can mitigate the impact, significantly improving the effect of suppressing gaps in the screw fastening portion and thus preventing loosening of the plug cover 30. In this embodiment, the connecting conductor 14 has a semi-cylindrical shape that is open on one side relative to the axis O of the plug 1, and has a smaller axial cross-sectional area than the mounting sleeve. Therefore, the bending stiffness of the cantilever structure decreases at the location of the connecting conductor 14. That is, even when the load on the cable 50 is relatively small, the bending displacement of the cantilever structure increases. As described above, by providing the elastic ring mounting portion 16g and the elastic ring 40 on the mounting sleeve 16, the effect of preventing loosening of the plug cover 30 is even more significant.

[0088] When the elastic ring mounting portion 16g is formed on the rod portion 4s, the outer diameter of the elastic ring mounting portion 16g is easily constrained by the nominal diameter of the external thread portion 13 in the relationship where the rod portion 4s with the external thread portion 13 needs to be screwed into the internal thread portion 31 on the plug cover 30 side. Therefore, there is a problem that it is slightly difficult to sufficiently ensure the deformation absorption space of the elastic ring 40 formed on the outer peripheral edge side of the elastic ring 40. In contrast, for the mounting sleeve 16 without the external thread portion 13, since there is no such constraint, it has the advantage of easily ensuring the deformation absorption spaces A and A' of the elastic ring 40.

[0089] exist Figure 7 In this design, the rear end of the mounting sleeve 16 is a reduced-diameter section 16e, which widens the gap g0 between the elastic ring mounting section 16g and the plug cover 30. As a result, a larger diameter elastic ring 40 can be assembled while ensuring sufficient deformation absorption spaces A and A'. This significantly improves the effect of preventing the plug cover 30 from loosening. Furthermore, by ensuring sufficient deformation absorption spaces A and A' for the elastic ring 40, it is also possible to suppress the occurrence of the elastic ring 40 biting into the gaps g1 and g2 between the plug cover 30 and the cable mounting section 7.

[0090] Next, when the plug cover 30 is screwed into the plug body 8 (cable mounting part 7) by manual tightening, a strong, instantaneous reverse torque is applied to the plug body 8 and the plug cover 30. This is important for creating a tightening structure that is less prone to loosening. In the above structure, since the plug cover 30 abuts against the flange 12, the outer peripheral surface of the flange 12 is exposed outside the plug cover 30. Therefore, in addition to the outer peripheral surface of the plug cover 30, a knurled portion 4r can also be engraved on the outer peripheral surface of the flange 12. Thus, until it abuts against the flange 12, the anti-slip effect when the plug cover 30 is screwed in by manual tightening is significant, and the instantaneous torque applied by manual tightening can be easily implemented. In particular, if a cloth (or the hem of a garment) is used to cover the outer peripheral surface of the flange 12 and the outer peripheral surface of the plug cover 30 for fastening, the anti-slip effect brought about by the knurled parts 4r, 30r1 to 30r3 is further enhanced. Even if it is manually fastened, the amount of tightening after the plug cover 30 and the flange 12 come into contact can be increased, and a firm threaded fastening state can be obtained.

[0091] In addition, such as Figure 8As shown, regarding the plug cover 30 side, the circumferential valley-shaped portion 30c serves as the finger contact portion when the plug cover 30 is screwed into the plug body 8. Furthermore, by engraving knurled portions 30r1 to 30r3 on the top surfaces of the first ribs 30b1 and 30b3 on both sides of the valley-shaped portion 30c and the second rib 30b2 at the bottom of the valley, and by offsetting the top surface of the second rib 30b2 from the top surfaces of the first ribs 30b1 and 30b3, the three ribs and the knurled portions 30r1 to 30r3 can strongly grip the fingers used for screwing in the plug by accustoming the fingertips to the inner surface of the valley-shaped portion 30c, thus enabling more effective tightening of the plug cover 30.

[0092] It should be noted that, in the plug 1 of this embodiment, the following structure is further adopted to prevent the cable 50 from detaching. For example... Figures 4-6 As shown, in the grounding metal fitting 4, a cylindrical mounting sleeve 16, which is coupled to the rear end of the connecting conductor 14, has an internally threaded hole 20 extending radially through its peripheral wall. A fixing screw 17 is screwed into this internally threaded hole 20. The front end of the foot of the fixing screw 17 protrudes towards the inside of the mounting sleeve 16, and the screwing compression force clamps and holds the cable 50 between itself and the peripheral wall of the mounting sleeve 16. The fixing screw 17 is configured as a hexagonal set screw, with a recess 17a formed on the end face abutting the cable 50, and similarly, a tool engagement hole 17b for engaging tools such as hexagonal wrenches is formed on the opposite end face.

[0093] like Figure 6 As shown, the cable 50 is compressed and deformed into a roughly heart-shaped cross-section by creating a recess 51c at the contact point with the fixing screw 17, and is held within the mounting sleeve 16. Specifically, the tip of the fixing screw 17 penetrates the insulating sheath 51 and makes electrical contact with the shielding conductor layer 52. This contact is not formed by welding, but mechanically. On the other hand, the insertion of the tip of the fixing screw 17 does not reach the intermediate insulation layer 54, ensuring insulation between the core wire 55 and the shielding conductor layers 52 and 53. In addition, a portion of the insulating sheath 51 of the cable 50 is also inserted into the recess 17a of the fixing screw 17.

[0094] Furthermore, on the opposite side abutting the fixing screw 17, in the area of ​​the inner circumferential surface of the mounting sleeve 16 that contacts the cable 50, a circumferentially engaged protrusion 18 is integrally formed along the inner circumferential surface. This engaged protrusion 18 bears the screwing compression force of the fixing screw 17 via the cable 50, and a portion of it engages with the insulating sheath 51. Therefore, even when a stronger tensile force is applied to the cable 50, the sliding displacement of the cable 50 relative to the inner surface of the mounting sleeve 16 is prevented by the engaged protrusion 18, effectively suppressing the loosening of the fixing screw 17.

[0095] like Figures 15-17As shown, the biting protrusion 18 formed on the inner circumferential surface of the mounting sleeve 16 is a circumferentially formed ridge portion 18a. Therefore, the biting length of the biting protrusion 18 relative to the insulation sheath 51 of the cable 50 becomes larger, further improving the effect of suppressing the sliding displacement of the cable 50 relative to the mounting sleeve 16. Furthermore, since the biting force of the biting protrusion 18 relative to the insulation sheath 51 is dispersed, it is less likely that the biting protrusion 18 will penetrate the insulation sheath 51. The ridge portion is formed in multiple rows along the axial direction of the mounting sleeve 16 on the inner circumferential surface, further improving the above-mentioned effects.

[0096] Here, when a strong torsional torque is applied to the cable 50, the insulation sheath 51 of the cable 50 may slide along the circumference of the mounting sleeve 16, which may easily cause the fixing screw 17 to loosen. In particular, when a protrusion (engulfing protrusion 18) is formed throughout the entire circumference of the inner circumference of the mounting sleeve 16, if a strong torsional torque is applied to the cable 50, the insulation sheath 51 of the cable 50 may easily slide along the circumference of the sleeve, i.e., along the length of the protrusion. In this case, it is effective to provide a sliding displacement preventing part to prevent the protrusion (engulfing protrusion 18) from sliding relative to the insulation sheath 51 in the circumferential direction.

[0097] like Figure 15 As shown, the sliding displacement blocking part can be formed as a cut recess 19 formed by partially cutting the protruding part (biting protrusion 18) at the middle position in the circumferential direction. Figure 3 As shown on the right side, the notch recess 19 can, for example, be formed as an elongated through hole. Figure 15 and Figure 16 As shown, in the notch recess 19, the insulation sheath 51 of the cable 50 is pressed outward in the radial direction to form an insulation sheath pressing portion 51a. Specifically, as... Figure 15 As shown, the cut end 18s of the protruding strip 18a abuts against the insulating sheath pressing part 51a, effectively preventing the cable 50 from sliding relative to the mounting sleeve 16 in the circumferential direction. It should be noted that, as... Figure 17 As shown, in the section where the recessed portion 19 is not formed on the inner circumferential surface of the mounting sleeve 16, all the multiple rows of raised portions 18a bite into the insulating outer sheath 51.

[0098] The embodiments of the plug for electronic plucked string instruments of the present invention have been described above, but the present invention is not limited thereto. Figure 14An example is shown where an elastic ring mounting portion 116g is formed at the base end of the external thread portion 13 formed on the rod portion 4s (adjacent to the flange 12), and the rear end face 12s of the flange 12 also serves as a main body side ring support portion. A circumferential countersunk hole 132k is formed on the inner circumferential surface of the plug cover 30 between its front side opening edge and the front end edge of the internal thread portion 31. The bottom surface of the countersunk hole 132k is a cap-side stepped surface 132j. The elastic ring 40 mounted on the elastic ring mounting portion 116g is compressed between the rear end face 12s of the flange 12 and the cap-side stepped surface 132j. It should be noted that the arrangement of the elastic ring mounting portion and the elastic ring can be combined in… Figure 14 The structure and setting of the 4s rod Figure 2 The structure of the mounting sleeve 16 can also be set on either side.

[0099] Explanation of reference numerals in the attached figures

[0100] 1. Plug for electronic plucked string instruments; 3. Main metal fitting; 3b. Core wire insertion hole; 3c. Engaging recess; 3f. Terminal flange; 3t. Front end; 4. Grounding metal fitting; 4c. Countersunk hole; 4r. Knurled part; 4s. Rod; 5. Plug side insulation layer; 5f. Insulating flange; 6. Insulating ring; 7. Cable mounting part; 8. Plug body; 9. Main terminal part; 10. Terminal metal fitting; 10a. Solder receiving part; 12. Flange; 12e. Reduced diameter part; 12s. Rear end face; 13. External thread part; 14. Connecting conductor; 15. Welding surface; 16. Mounting sleeve; 16e. Reduced diameter part; 16g. Elastic ring mounting part; 16j. Main body side ring support part; 16m. Main body; 17. Fixing screw; 17a. Recess; 17b. Tool engaging hole; 18. Engaging protrusion; 18a. Raised strip part; 18s. Cut end; 19. Notched recess; 20. Internal threaded hole; 30. Plug cover; 30b1, 30b3. First rib; 30b2. Second rib; 30c. Valley-shaped part; 30r1~r3. Knurled part; 30t. Front end face; 31. Internal threaded part; 32a. Front side inner circumferential surface; 32b. Rear side inner circumferential surface; 32j. Cover side stepped surface; 40. Elastic ring; 50. Cable; 51. Insulating outer sheath; 51a. Insulating outer sheath press-in part; 51c. Recess; 52, 53. Shielding conductor layer; 54. Intermediate insulation layer; 55. Core wire; 56~58. Welding part; 100. Electric guitar; 101. Instrument side socket; 110. Amplifier; 111. Amplifier side socket; 116g. Elastic ring mounting part; 132j. Cap side stepped surface; 132k. Countersunk hole; A, A'. Deformation absorption space; g0, g1, g2. Gap.

Claims

1. A plug for an electronic plucked string instrument, used for connecting a cable to a socket of an electronic plucked string instrument or amplifier and installed at the end of said cable, characterized in that... have: The plug body is made of metal and includes a main terminal portion, a flange, and a cable mounting portion. The main terminal portion is shaped to engage with the socket. In the axial direction of the main terminal portion, when the insertion side of the main terminal portion toward the socket is defined as the front end side, the flange is integrated with the rear side of the main terminal portion. The cable mounting portion has a smaller diameter than the flange and is integrated with the rear side of the flange, and has an external thread on its outer peripheral surface. The cable mounting portion is used to mount the end of the cable. A metal plug cover is cylindrical in shape, open at both ends along its axial direction, and has an internal thread on its inner circumferential surface that engages with the external thread of the cable mounting portion, thus covering the cable mounting portion; and The elastic ring, made of a polymer elastic material, is grounded to the inner surface of the plug cover on its outer peripheral edge and to the outer surface of the cable mounting part on its inner peripheral edge. The plug body includes: a resilient ring mounting portion formed on the outer peripheral surface of the cable mounting portion; and a body side ring support portion formed adjacent to the front side of the resilient ring mounting portion in the axial direction, which is larger in diameter than the resilient ring mounting portion and restricts the forward movement of the resilient ring of the resilient ring mounting portion. A cover-side ring support portion is formed on the inner surface of the plug cover. The cover-side ring support portion extends radially inward relative to the axis of the main terminal portion and contacts the rear outer surface of the elastic ring mounted on the elastic ring mounting portion. The elastic ring is compressed along the axial direction between the main body side ring support portion and the cover-side ring support portion. The front end face of the plug cover directly abuts against the rear end face of the flange.

2. The plug for an electronic plucked string instrument according to claim 1, wherein, The cover-side ring support portion is a cover-side stepped surface with a larger diameter at the front edge than at the rear edge in the axial direction. This cover-side stepped surface is an inclined surface whose diameter gradually decreases towards the rear in the axial direction.

3. The plug for an electronic plucked string instrument according to claim 1, wherein, The elastic ring mounting portion is formed into a groove by receiving the inner peripheral edge of the elastic ring, such that the outer peripheral edge of the elastic ring is offset from the inner surface of the plug cover in a radial direction.

4. The plug for an electronic plucked string instrument according to claim 1, wherein, The outer diameter of the elastic ring is set such that, in the non-compressed state, a gap is created between it and the inner circumferential surface of the front end side of the cover-side ring support portion of the plug cover.

5. The plug for an electronic plucked string instrument according to claim 4, wherein, The diameter of the elastic ring is set such that, before the front end face of the plug cover abuts against the rear end face of the flange, it forms a compressed state in the radial direction through the inner circumferential surface of the front end side of the stepped surface of the plug cover.

6. The plug for an electronic plucked string instrument according to claim 5, wherein, When the wire diameter of the elastic ring is set to d, and the deformation of the elastic ring generated in the normal direction of the stepped surface of the cover side ring support portion when the front end face of the plug cover abuts against the rear end face of the flange is set to Δd, the value of Δd / d is adjusted to be 0.1 or more and 0.3 or less.

7. The plug for an electronic plucked string instrument according to claim 1, wherein, The portion located further rearward than the external thread portion of the cable mounting portion becomes a cantilever structure portion. The cantilever structure portion has a screw-fastening portion that engages with the internal thread portion of the plug cover as its base end, and a radial gap is continuously formed between it and the inner surface of the plug cover in the circumferential direction. The elastic ring mounting portion and the elastic ring are disposed on the rear end side of the cantilever structure portion in the axial direction.

8. The plug for an electronic plucked string instrument according to claim 1, wherein, The cable mounting portion includes: a rod portion integrally formed adjacent to the rear side of the flange; and a mounting sleeve, which is connected to the rear side of the rod portion via a connecting conductor and is formed as a cylinder with openings at both ends in the axial direction, allowing the cable to be inserted from the rear opening along the axial direction. The external thread is formed on the outer peripheral surface of the rod, and the internal thread is formed on the front end of the inner surface of the plug cover. The elastic ring mounting portion and the elastic ring are disposed on at least one of the rod portion and the mounting sleeve.

9. The plug for an electronic plucked string instrument according to claim 8, wherein, The device includes a cantilever structure located further rearward than the external thread of the cable mounting portion, with a screw-on fastening portion that engages with the internal thread of the plug cover as its base end, and a radially continuous gap formed between it and the inner surface of the plug cover in the circumferential direction. The connecting conductor has a smaller axial cross-sectional area than the mounting sleeve and forms the cantilever structure together with the mounting sleeve. The elastic ring mounting portion and the elastic ring are disposed on the mounting sleeve.

10. The plug for an electronic plucked string instrument according to claim 9, wherein, The rear end of the mounting sleeve in the axial direction is a reduced diameter portion that is narrowed by the stepped surface on the sleeve side. The stepped surface on the sleeve side forms the main body side ring support portion, and the outer peripheral surface of the reduced diameter portion forms the elastic ring mounting portion.

11. The plug for an electronic plucked string instrument according to claim 1, wherein, Knurling is provided on both the outer peripheral surface of the flange and the outer peripheral surface of the plug cover.

12. The plug for an electronic plucked string instrument according to claim 11, wherein, On the outer peripheral surface of the plug cover, a circumferential valley-shaped portion is formed at the middle position in the axial direction, and a pair of circumferential first ribs are formed on the outer peripheral surface in a manner adjacent to the two sides of the valley-shaped portion in the axial direction. A second rib is formed at the bottom position of the valley-shaped portion, with its top surface offset further towards the bottom of the valley than the top surface of the first rib. The knurled portion is individually engraved on the top surface of the pair of first ribs and the top surface of the second rib.

13. A cable having a plug for an electronic plucked string instrument as claimed in claim 1.

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