Patent Description:
Record players play back sound signals recorded on records by converting oscillation of needles mechanically tracing sound grooves of the records into electrical signals. Needles are attached to pick-up cartridges (hereinafter referred to as "cartridges"). Cartridges are attached to head shells (for example, see <CIT>).

Head shells hold cartridges. Head shells are attached to tone arms of record players. Head shells transmit electrical signals from the cartridges to signal lines wired in the tone arms.

A distal end (needle tip) of the needle of each of the cartridges is worn in accordance with the use time of the needle. Therefore, the needle of each of the cartridges is changed for each predetermined use time. In addition, the sound quality of sound (playback sound) played back by the record player differs according to the type of the cartridge. Thus, the cartridge can be changed in accordance with the sound quality desired by a user of the record player. Generally, when the needle and/or the cartridge is changed, the head shell is detached from the tone arm.

When the head shell (in particular, the head shell after the cartridge is changed) is attached to the tone arm, the position of the needle tip with respect to the record is easily shifted from a proper position. The position of the needle tip with respect to the record is regulated by regulating overhang. Overhang is a distance obtained by subtracting a distance between the fulcrum of the tone arm and the rotation center (spindle center) of the record from a distance between the fulcrum of the tone arm and the needle tip. When the overhang is not proper, malfunction, such as tracking errors and degradation in sound quality of the playback sound, easily occurs.

Overhang is regulated by user's moving of the position of the cartridge with respect to the head shell. The cartridge is required to be attached in parallel with the head shell in bottom (plan) view. Therefore, the user regulates the position of the needle tip and inclination of the cartridge with respect to the head shell, in regulation of the overhang.

A head shell that enables regulation of overhang in a state in which the cartridge is attached to the head shell has been proposed (for example, see "<NPL>).

The head shell disclosed in "User's Manual for AT-LH13/OCC" includes a cylinder and a head shell main body. The cylinder includes a connector part and a holding part. The connector part is attached to the tone arm. The holding part holds the head shell main body. The holding part is inserted through a through hole disposed in a rear end wall of the head shell main body. The head shell main body is fixed to the holding part with a bolt and a set screw.

In the head shell disclosed in "User's Manual for AT-LH13/OCC", when the bolt and the set screw are unfastened, the head shell main body is movable with respect to the cylinder. Therefore, in the state in which the cylinder is attached to the tone arm, the user can regulate the position of the head shell main body with respect to the cylinder. Accordingly, the overhang of the head shell can be regulated in the state in which the cartridge is attached to the head shell.

However, in the head shell disclosed in "User's Manual for AT-LH13/OCC", the head shell main body is movable in each of the axial direction and the circumferential direction of the cylinder. Therefore, in regulation of overhang, the head shell main body easily rotates in the circumferential direction of the cylinder with respect to the cylinder. Thus, in regulation of overhang, the head shell main body is often attached in an inclined state to the horizontal plane. When the head shell main body is inclined to the horizontal plane, the needle tip does not abut against the sound groove at a proper angle (angle at which the axis of the needle is perpendicular to the record). As a result, malfunction causing damage to the user's possessions (such as breakage of the needle tip and/or damage to the record) may occur, as well as deterioration in sound quality of the playback sound. Accordingly, in the head shell disclosed in "User's Manual for AT-LH13/OCC", regulation of overhang also requires regulation (regulation of levelness) to set the head shell main body in parallel with the horizontal plane.

When levelness is regulated by visual observation, the head shell has no part serving as a clear standard for regulation by visual observation. Therefore, regulation of levelness by visual observation is not easy. Accordingly, regulation of levelness using a level is usually performed among regular users who usually use record players. However, many regular users feel it troublesome to perform regulation of levelness using a level.

Document <CIT> discloses a head shell which is movable relative to a cylinder in an axial direction. A fixing screw is provided to fix the shell to the cylinder.

Document <CIT> discloses a head shell having a scale for rotational alignment of the head shell with a cylinder to which it is attached.

In the meantime, with a record boom created in recent years, record players have been used increasingly by beginners (young people) who are not accustomed to use record players, as well as regular users. The regular users sufficiently understand the importance of regulation of overhang described above, and are familiar with the regulation. Therefore, the regular users can regulate overhang to a certain degree. By contrast, the beginners do not sufficiently understand the importance of regulation of overhang, and are unfamiliar with regulation of overhang. Therefore, the beginners have difficulty in thinking of using a level, and few beginners have a level. Specifically, regulation of overhang (in particular, regulation of levelness) is not easy for beginners.

To solve such a problem, in the case where a head shell is provided with a regulation mechanism for regulation of overhang, including regulation of levelness, additional components and/or processing are required. As a result, productivity of the head shell decreases.

An object of the present invention is to provide a head shell that enables easy and accurate regulation of overhang.

The head shell according to the present invention is defined by claim <NUM>.

According to the present invention, regulation of overhang can be performed easily and accurately.

Embodiments of a head shell according to the present invention will now be described with reference to the attached drawings.

<FIG> is a perspective view illustrating an usage example of a head shell according to the present invention.

<FIG> illustrates a head shell <NUM>, a pickup cartridge (hereinafter referred to as "cartridge") C, a tone arm P1 and a turntable P2 of a record player P, and a record R placed on the turntable P2.

The cartridge C includes a needle C1 that traces the sound groove of the record R. The cartridge C converts oscillation of the needle C1 generated by tracing the sound groove with the needle C1 into an electrical signal. The tone arm P1 supports the cartridge C via the head shell <NUM>, and applies certain pressure (needle pressure) to the needle C1. The tone arm P1 includes a connector P11. The connector P11 is disposed at a distal end of the tone arm P1. The head shell <NUM> is attached to the connector P11. The turntable P2 rotates the record R at certain speed.

The head shell <NUM> holds the cartridge C. In other words, the head shell <NUM> is an adaptor to attach the cartridge C to the tone arm P1. The cartridge C is attached to (held to) the head shell <NUM> with attachment screws C2 and C3. The head shell <NUM> is attached to the connector P11 of the tone arm P1 of the record player P.

In the following explanation, the term "rear" indicates a direction in which the connector P11 is positioned with respect to the head shell <NUM> attached to the tone arm P1. The term "front" indicates a direction in which the cartridge C held to the head shell <NUM> is positioned with respect to the connector P11 to which the head shell <NUM> is attached. The term "downward (under)" indicates a direction in which the record R is positioned with respect to the head shell <NUM> when the needle C1 traces the sound groove of the record R. The term "upward (above)" indicates a direction in which the head shell <NUM> is lifted when the user separates the needle C1 from the record R.

<FIG> is a perspective view illustrating an embodiment of the head shell <NUM>.

<FIG> is an exploded perspective view of the head shell <NUM>.

The head shell <NUM> includes a head shell main body <NUM>, a cylinder <NUM>, a buffer member <NUM>, an insulating member <NUM>, a first fixing screw <NUM>, a second fixing screw <NUM>, a finger <NUM>, and a finger attachment screw <NUM>.

The head shell main body <NUM> holds the cartridge C (see <FIG>). The head shell main body <NUM> has an L shape in side view. The head shell main body <NUM> is made of metal, such as aluminum. The head shell main body <NUM> includes a first holding part <NUM> and a second holding part <NUM>.

The first holding part <NUM> holds the cartridge C (see <FIG>). The first holding part <NUM> has a rectangular and plate-like shape that is long in the front-rear direction. The first holding part <NUM> includes four screw insertion holes 11h1, 11h2, 11h3 and 11h4, and a cylinder guide groove <NUM> (see <FIG>).

The screw insertion holes 11h1 to 11h4 are through holes through which the attachment screws C2 and C3 (see <FIG>) are inserted. The screw insertion holes 11h1 to 11h4 are disposed in a front part of the first holding part <NUM>.

<FIG> is a back view of the head shell <NUM>.

<FIG> is a cross-sectional view of the head shell <NUM>, taken along line A-A of <FIG>.

<FIG> is a cross-sectional view of the head shell <NUM>, taken along line B-B of <FIG>.

The cylinder guide groove <NUM> guides movement of the below-mentioned cylinder <NUM> in the front-rear direction. An internal surface of the cylinder guide groove <NUM> has an arc shape in the cross-sectional view illustrated in <FIG>. The internal surface extends along an external circumferential surface (the below-mentioned external circumferential surface 23a of a main body holding part <NUM>) of the cylinder <NUM>. The cylinder guide groove <NUM> is disposed on a lower surface 11a in a rear part of the first holding part <NUM>. The cylinder guide groove <NUM> communicates with the below-mentioned insertion hole 12h1.

The second holding part <NUM> is held to the cylinder <NUM>. The second holding part <NUM> has a plate-like shape extending along a up-down direction. The second holding part <NUM> is disposed at a rear end of the first holding part <NUM> to stand straight downward from the first holding part <NUM>. The second holding part <NUM> is integrated with the first holding part <NUM>. The second holding part <NUM> includes an insertion hole 12h1, a first screw hole 12h2, a second screw hole 12h3, a screw insertion hole 12h4, a slit <NUM>, and a regulating groove <NUM>.

It should be noted that second holding part may be formed separately from the first holding part. Specifically, for example, the second holding part may be coupled to the first holding part with a coupling member, such as a screw.

The insertion hole 12h1 is a through hole through which the cylinder <NUM> is inserted (holding the cylinder <NUM>). The insertion hole 12h1 has a circular shape in back view. The insertion hole 12h1 is disposed in the center of the second holding part <NUM>. The insertion hole 12h1 penetrates the second holding part <NUM> in the front-rear direction (right-left direction on the paper in <FIG>). An internal circumferential surface in an upper part of the insertion hole 12h1 is integrally formed with the cylinder guide groove <NUM>.

The first screw hole 12h2 is a through hole into which the first fixing screw <NUM> is screwed. The first screw hole 12h2 is disposed in substantially the center of a right side surface of the second holding part <NUM>. The first screw hole 12h2 communicates with the insertion hole 12h1.

The second screw hole 12h3 is a through hole into which the second fixing screw <NUM> is screwed. The second screw hole 12h3 is disposed under the insertion hole 12h1 and in the right side surface of the second holding part <NUM>.

The screw insertion hole 12h4 is a through hole through which the second fixing screw <NUM> is inserted. The screw insertion hole 12h4 is disposed under the insertion hole 12h1 and in a left side surface of the second holding part <NUM>. The screw insertion hole 12h4 is disposed coaxially with the second screw hole 12h3.

The slit <NUM> is a gap of which an interval varies according to fastening of the second fixing screw <NUM>. The slit <NUM> is disposed in the center of the second holding part <NUM> in the right-left direction, and in a lower end part of the second holding part <NUM>. The slit <NUM> penetrates the second holding part <NUM> in the front-rear direction, and communicates with the insertion hole 12h1. The slit <NUM> is positioned between the second screw hole 12h3 and the screw insertion hole 12h4. In the second holding part <NUM>, parts located on the left and the right of the slit <NUM> are thin parts having a small thickness in the right-left direction.

The regulating groove <NUM> assists regulation of the levelness of the head shell main body <NUM>, in the below-mentioned regulation of overhang. The regulating groove <NUM> is a long groove. The regulating groove <NUM> is disposed on the center of a rear surface 12a of the second holding part <NUM> in the right-left direction, and above the insertion hole 12h1. The regulating groove <NUM> extends upward from the insertion hole 12h1 side. The regulating groove <NUM> serves as a second sign (recessed part) in the present invention. The rear surface 12a serves as a back surface in the present invention. Regulation of levelness with the regulating groove <NUM> will be described later.

Referring now back to <FIG>, the cylinder <NUM> holds the head shell main body <NUM>. The cylinder <NUM> is made of metal, such as aluminum. The cylinder <NUM> is inserted through the insertion hole 12h1 and holds the head shell main body <NUM>. The cylinder <NUM> includes a connector part <NUM>, a projection part <NUM>, a main body holding part <NUM>, and four terminal pins <NUM>, <NUM>, <NUM> and <NUM>.

The connector part <NUM> mechanically connects the head shell <NUM> with the tone arm P1, and electrically connects the terminal pins <NUM> to <NUM> with a signal line of the tone arm P1. The connector part <NUM> has a columnar shape, and includes a cylindrical external circumferential surface 21a. The external circumferential surface 21a serves as a connector external circumferential surface in the present invention. The connector part <NUM> is attached to the connector P11.

The projection part <NUM> fixes the connector part <NUM> to the connector P11. The projection part <NUM> has a columnar shape. A part of the external circumferential surface 21a projects from the external circumferential surface 21a in the radial direction of the connector part <NUM> and thereby the projection part <NUM> is formed. The projection part <NUM> is disposed on the upper surface (upper end surface) of the external circumferential surface 21a along the up-down direction. The projection part <NUM> serves as the first sign in the present invention.

The connector part <NUM> is attached to the connector P11 by a Bayonet attachment method in the same manner as Bayonet Neill Concelman (BNC) connectors. Specifically, by arrival of the projection part <NUM> at the end of a lock groove (not shown) of the connector P11, the connector part <NUM> is attached to the connector P11. By contrast, by separation of the projection part <NUM> from the lock groove, the connector part <NUM> is detached from the connector P11. Specifically, the projection part <NUM> can fix the connector part <NUM> to the connector P11, and the connector part <NUM> is attachable to and detachable from the connector P11.

The main body holding part <NUM> is inserted through the insertion hole 12h1, and holds the head shell main body <NUM>. The main body holding part <NUM> functions as the movement axis and the rotation axis of the head shell main body <NUM>, in the below-described regulation of overhang. The main body holding part <NUM> has a bottomed cylindrical shape having an opening at a front end. The main body holding part <NUM> serves as the holding part in the present invention. The main body holding part <NUM> includes a cylindrical external circumferential surface 23a and a screw guide groove 23b. The external circumferential surface 23a serves as the cylinder external circumferential surface in the present invention.

The external diameter of the main body holding part <NUM> is larger than the external diameter of the connector part <NUM>. The main body holding part <NUM> is disposed in front of the connector part <NUM> and integrally formed with the connector part <NUM>. In back view, the center position of the main body holding part <NUM> in the radial direction is the same as the center position of the connector part <NUM> in the radial direction. Specifically, a central axis 20x of the cylinder <NUM> is superimposed on a central axis 21x of the connector part <NUM> and a central axis 23x of the main body holding part <NUM>. Each of the central axes 20x, 21x, and 23x is parallel with the front-rear direction (right-left direction on the paper in <FIG>). Accordingly, the axial direction of the cylinder <NUM> (the connector part <NUM> and the main body holding part <NUM>) is the front-rear direction.

<FIG> is an enlarged cross-sectional view obtained by enlarging a part of <FIG>.

<FIG> is an enlarged cross-sectional view obtained by further enlarging a part of <FIG>.

<FIG> illustrates a state in which the first fixing screw <NUM> is unfastened with a two-dot chain line.

The screw guide groove 23b guides the below-described distal end part <NUM> of the first fixing screw <NUM> in the front-rear direction, and restricts movement (rotation) of the distal end part <NUM> in the circumferential direction of the cylinder <NUM>. The screw guide groove 23b serves as the groove in the present invention. As illustrated in <FIG>, the screw guide groove 23b is disposed on a right side surface of the external circumferential surface 23a. In the external circumferential surface 23a, the right side surface is a surface facing the center side of the record R when the needle C1 (see <FIG>) traces the sound groove of the record R (see <FIG>). The screw guide groove 23b extends from a front end to a rear end of the main body holding part <NUM> along the axial direction (front-rear direction) of the cylinder <NUM>. The screw guide groove 23b includes a bottom surface 23b1, an upper side surface 23b2 disposed at an upper end of the bottom surface 23b1, and a lower side surface 23b3 disposed at a lower end of the bottom surface 23b1.

Referring now back to <FIG>, the terminal pins <NUM> to <NUM> transmit an electrical signal from the cartridge C to the signal line (not shown) of the tone arm P1. The signal line is wired inside the tone arm P1. The terminal pins <NUM> to <NUM> are made of metal having excellent conductivity, such as copper. The terminal pins <NUM> to <NUM> penetrate the connector part <NUM> and the insulating member <NUM> in the front-rear direction, and are fixed to the connector part <NUM>. The terminal pins <NUM> to <NUM> are connected with a terminal (not shown) of the connector P11, when the connector part <NUM> is attached to the connector P11. The electrical signal from the cartridge C is transmitted to the signal line of the tone arm P1 via the terminal pins <NUM> to <NUM> and the terminal.

The cylinder <NUM> is inserted through the insertion hole 12h1 from the rear, and penetrates the rear surface 12a (second holding part <NUM>). In this state, the substantial center part of the main body holding part <NUM> in the front-rear direction is disposed in the insertion hole 12h1. As a result, the head shell main body <NUM> is held with the cylinder <NUM>. A front upper part of the main body holding part <NUM> is disposed in the cylinder guide groove <NUM>. The bottom surface 23b <NUM> (see <FIG>) of the screw guide groove 23b is opposed to the first screw groove 12h2. A rear part of the main body holding part <NUM> projects rearward from the second holding part <NUM>. The connector part <NUM> is disposed in the rear of the second holding part <NUM>. The projection part <NUM> is disposed in the rear of the second holding part <NUM> and apart from the second holding part <NUM>.

In the following explanation, the term "axial direction" indicates the axial direction (front-rear direction) of the cylinder <NUM>, unless otherwise described. The term "axial view" indicates an axial view (front view or back view) of the cylinder <NUM>, unless otherwise described. The term "circumferential direction" indicates the circumferential direction of the cylinder <NUM>, unless otherwise described. The term "radial direction" indicates the radial direction of the cylinder <NUM>, unless otherwise described.

The projection part <NUM> is disposed under the regulating groove <NUM> in axial view. When the regulating groove <NUM> is disposed along the up-down direction, the projection part <NUM> and the regulating groove <NUM> are disposed in line in the radial direction of the cylinder <NUM> in axial view. In this state, a center line 121x of the regulating groove <NUM> is superimposed on a central axis 22x of the projection part <NUM> in axial view. The center line 121x is a straight line passing through the center of the regulating groove <NUM> in the right-left direction in axial view. The center line 121x and the central axis 22x are orthogonal to the central axis 20x. Specifically, the regulating groove <NUM> is disposed on the rear surface 12a along the radial direction in axial view. Therefore, the user can regulate the position of the head shell main body <NUM> in the circumferential position with respect to the cylinder <NUM> by checking the position of the regulating groove <NUM> with respect to the projection part <NUM> by visual observation, when the user rotates the head shell main body <NUM> in the circumferential direction with respect to the cylinder <NUM>. As described above, the regulating groove <NUM> and the projection part <NUM> function as a regulation assistance mechanism assisting regulation of the position of the head shell main body <NUM> in the circumferential position with respect to the cylinder <NUM>.

The buffer member <NUM> protects each of the connector P11 and the cylinder <NUM> (the rear surface of the main body holding part <NUM>), when the connector part <NUM> is attached to the connector P11 (see <FIG>). The buffer member <NUM> is made of synthetic resin, such as rubber, and has a ring-shape and a plate-like shape. The buffer member <NUM> is attached to the external circumferential surface 21a positioned at the front end of the connector part <NUM>, and abuts against the rear surface of the main body holding part <NUM>.

The insulating member <NUM> insulates spaces between the terminal pins <NUM> to <NUM>. The insulating member <NUM> is made of, for example, synthetic resin, and has a disk-like shape. The insulating member <NUM> is attached to the rear surface of the connector part <NUM>.

Referring now back to <FIG>, the first fixing screw <NUM> fixes the head shell main body <NUM> to the cylinder <NUM>, and restricts movement (rotation) of the head shell main body <NUM> in the circumferential direction. The first fixing screw <NUM> is a head flat point set screw, and includes a distal end surface 50a having a flat shape. The first fixing screw <NUM> is made of, for example, stainless steel.

The external circumferential surface of the distal end of the first fixing screw <NUM> is a chamfered surface 50b that is chamfered. The first fixing screw <NUM> is screwed into the first screw hole 12h2 of the second holding part <NUM>. The distal end of the first fixing screw <NUM> projects from the first screw hole 12h2 into the insertion hole 12h1, and is disposed in the screw guide groove 23b. A central axis 50x of the first fixing screw <NUM> is orthogonal to the central axis 20x.

In the first fixing screw <NUM>, a part (hereinafter referred to as "distal end part <NUM>") disposed in the screw guide groove 23b serves as the distal end part in the present invention. Specifically, the first fixing screw <NUM> includes a distal end part <NUM>. In the present embodiment, the distal end part <NUM> includes the distal end surface 50a and the chamfered surface 50b.

In the circumferential direction, spaces G1 and G2 are defined between the distal end part <NUM> and the screw guide groove 23b. The space G1 is defined between the distal end part <NUM> and the upper side surface 23b2. The space G2 is defined between the distal end part <NUM> and the lower side surface 23b3.

When the first fixing screw <NUM> is fastened, the distal end surface 50a of the first fixing screw <NUM> abuts against the bottom surface 23b <NUM> of the screw guide groove 23b. Specifically, the first fixing screw <NUM> can abut against the bottom surface 23b1 of the screw guide groove 23b. In this state, the head shell main body <NUM> is fixed to the cylinder <NUM> with the first fixing screw <NUM>. When the distal end surface 50a abuts against the bottom surface 23b1, the circumferential length of each of the spaces G1 and G2 is shortest. By contrast, when the first fixing screw <NUM> is unfastened, the distal end surface 50a is separated from the bottom surface 23b <NUM>. As a result, fixing of the head shell main body <NUM> to the cylinder <NUM> with the first fixing screw <NUM> is released. As described above, the first fixing screw <NUM> can fix the head shell main body <NUM> to the cylinder <NUM>. In other words, the first fixing screw <NUM> can fix the cylinder <NUM> to the head shell main body <NUM>.

The second fixing screw <NUM> changes the interval of the slit <NUM>. The second fixing screw <NUM> is, for example, a bolt including a head part, and made of, for example, a stainless steel. The second fixing screw <NUM> is inserted through the screw insertion hole 12h4 of the second holding part <NUM>, and screwed into the third screw hole 12h3.

When the second fixing screw <NUM> is fastened, the interval of the slit <NUM> is narrowed. Accordingly, the insertion hole 12h1 is slightly deformed toward the inside of the insertion hole 12h1 (the diameter of the insertion hole 12h1 is reduced). In this state, the force (hereinafter referred to as "fastening force") with which the insertion hole 12h1 fastens the cylinder <NUM> increases. As a result, the head shell main body <NUM> is fixed to the cylinder <NUM>. By contrast, when the second fixing screw <NUM> is unfastened, the interval of the slit <NUM> is widened, and returns to the original interval. As a result, the insertion hole 12h1 returns to the state before the deformation. In this state, the fastening force decreases. As a result, fixing of the head shell main body <NUM> to the cylinder <NUM> is released.

Referring now back to <FIG>, the finger <NUM> is a component under which the user's finger is hooked to lift and move the needle C <NUM> from the record R. The finger <NUM> is attached to a left side surface of the head shell main body <NUM> with the finger attachment screw <NUM>.

Relation between the head shell main body <NUM> and the cylinder <NUM> will now be described with reference to <FIG>.

As described above, each of the first fixing screw <NUM> and the second fixing screw <NUM> is unfastened, fixing of the head shell main body <NUM> to the cylinder <NUM> is released.

The cylinder <NUM> is rotatable in the circumferential direction with respect to the head shell main body <NUM> along the insertion hole 12h1 and the cylinder guide groove <NUM>. In this state, the cylinder <NUM> is rotated around the central axis 20x along the insertion hole 12h1 and the cylinder guide groove <NUM>.

By contrast, the head shell main body <NUM> is rotatable in the circumferential direction with respect to the cylinder <NUM> along the external circumferential surface 23a. In this state, the head shell main body <NUM> is rotated around the cylinder <NUM> serving as the rotation axis, along the external circumferential surface 23a. The range of rotation of the head shell main body <NUM> is restricted by abutment of the distal end part <NUM> against the screw guide groove 23b. Specifically, the head shell main body <NUM> is rotatable counterclockwise in back view until the distal end part <NUM> abuts against the upper side surface 23b2. That is, the head shell main body <NUM> is rotatable only within the angle range of an angle θ1 corresponding to the circumferential length of the space G1. By contrast, the head shell main body <NUM> is rotatable clockwise in back view until the distal end part <NUM> abuts against the lower side surface 23b3. Specifically, the head shell main body <NUM> is rotatable only within the angle range of an angle θ2 corresponding to the circumferential length of the space G2. In the present embodiment, the head shell main body <NUM> is rotatable only within each of angle ranges of approximately <NUM>° in the clockwise direction and the counterclockwise direction.

In addition, the cylinder <NUM> is movable (slidable) in the axial direction (front-rear direction) with respect to the head shell main body <NUM> along the insertion hole 12h1 and the cylinder guide groove <NUM>.

By contrast, the head shell main body <NUM> is movable (slidable) in the axial direction with respect to the cylinder <NUM> along the main body holding part <NUM> of the cylinder <NUM>. In this state, the distal end part <NUM> is guided to the screw guide groove 23b and moves in the axial direction. As described above, when the head shell main body <NUM> is rotated in the circumferential direction, the distal end part <NUM> abuts against the screw guide groove 23b. Therefore, the distal end part <NUM> is movable in the screw guide groove 23b only in substantially the axial direction. Specifically, the head shell main body <NUM> is movable only in substantially the axial direction with respect to the cylinder <NUM>.

The head shell main body <NUM> is fixed to the cylinder <NUM>, when one of the first fixing screw <NUM> and the second fixing screw <NUM> is fastened.

A method for regulating overhang in attachment of the cartridge C to the head shell <NUM> will now be described also with reference to <FIG>. The method for regulating overhang includes regulation of the position of the distal end (needle tip) of the needle C1 of the cartridge C and regulation of levelness of the head shell main body <NUM>. Overhang is regulated by the user of the record player P.

<FIG> is a bottom view of the head shell <NUM> to which the cartridge C is attached.

First, the user attaches the cartridge C to the lower surface 11a of the first holding part <NUM> of the head shell <NUM> using the attachment screws C2 and C3. At this stage, the cartridge C is positioned with respect to the head shell <NUM> such that the side surfaces of the cartridge C are parallel with the side surfaces of the first holding part <NUM> in bottom view.

Then, the user attaches the head shell <NUM> to the connector P11 of the tone arm P1. At this stage, the connector part <NUM> is fixed to the connector P11 with the projection part <NUM> and the lock groove of the connector P11. The rear surface 12a faces the tone arm P1 side.

Then, the user unfastens the first fixing screw <NUM> and the second fixing screw <NUM>. As a result, fixing of the head shell main body <NUM> to the cylinder <NUM> is released. Accordingly, the head shell main body <NUM> becomes movable in the axial direction with respect to the cylinder <NUM>. In addition, the head shell main body <NUM> becomes rotatable around the cylinder <NUM> serving as the rotation axis, in the angle range corresponding to the spaces G1 and G2 (see <FIG>) in the circumferential direction. Specifically, the regulating groove <NUM> becomes movable (rotatable) with respect to the projection part <NUM>.

Then, the user moves the head shell main body <NUM> in the front-rear direction to set the position of the needle tip of the needle C1 of cartridge C to a proper position Pa. As a result, the position of the needle tip is regulated to the proper position Pa.

In the example illustrated in <FIG>, by the user's moving of the head shell main body <NUM> forward, the position of the needle tip is regulated to the proper position Pa. In this state, the head shell main body <NUM> is movable freely in the axial direction by guiding of the distal end part <NUM> to the screw guide groove 23b. By contrast, the head shell main body <NUM> is rotatable in the circumferential direction until the distal end part <NUM> abuts against the screw guide groove 23b (the upper side surface 23b2, the lower side surface 23b3: see <FIG>). Therefore, when the user moves the head shell main body <NUM>, the head shell main body <NUM> is not rotated largely with respect to the cylinder <NUM>. As a result, the levelness of the head shell main body <NUM> is not changed greatly.

Then, the user fastens the first fixing screw <NUM> and the second fixing screw <NUM>. As a result, the head shell main body <NUM> is fixed to the cylinder <NUM>.

Then, the user detaches the head shell <NUM> from the connector P <NUM> of the tone arm P1.

Then, the user unfastens the first fixing screw <NUM>, and slightly unfastens the second fixing screw <NUM>. In this state, the insertion hole 12h1 holds the cylinder <NUM> (main body holding part <NUM>) with predetermined fastening force. When the user applies force exceeding the fastening force to the head shell main body <NUM>, the head shell main body <NUM> becomes movable with respect to the cylinder <NUM>. In other words, the head shell main body <NUM> does not move with respect to the cylinder <NUM> unless the user applies force exceeding the fastening force to the head shell main body <NUM>.

<FIG> is an enlarged back view obtained by partly enlarging the head shell <NUM>.

<FIG> illustrates the state in which each of the head shell main body <NUM>, the cylinder <NUM>, the buffer member <NUM>, the insulating member <NUM>, and the first fixing screw <NUM> is partly cut out. <FIG> also illustrates the state in which each of the head shell main body <NUM>, the cylinder <NUM>, and the first fixing screw <NUM> is cut along line B-B of <FIG>. <FIG> also illustrates the projection part <NUM> and the screw guide groove 23b with two-dot chain lines when the head shell main body <NUM> is rotated to the maximum with respect to the cylinder <NUM>.

Then, the user regulates the levelness of the head shell main body <NUM>. The levelness of the head shell main body <NUM> is regulated using the regulating groove <NUM> and the projection part <NUM>.

Then, the user rotates the head shell main body <NUM>, by using the position of the projection part <NUM> with respect to the regulating groove <NUM> as a criterion. Specifically, the user rotates the head shell main body <NUM> while viewing the regulating groove <NUM> and the projection part <NUM> such that the regulating groove <NUM> and the projection part <NUM> are disposed in line in the radial direction (such that the center line 121x of the regulating groove <NUM> is superimposed on the central axis 22x of the projection part <NUM>). As a result, the levelness of the head shell main body <NUM> is approximately regulated.

Then, the user fastens the first fixing screw <NUM> and the second fixing screw <NUM>.

Then, the user attaches the head shell <NUM> to the connector P11 of the tone arm P1. As a result, regulation of overhang by the user is completed.

As described above, the user can regulate the position of the needle tip without largely varying the levelness in regulation of overhang. In addition, the user can approximately regulate the levelness of the head shell main body <NUM> by visual observation.

In the embodiment described above, the head shell <NUM> includes the cylinder <NUM> attachable to and detachable from the connector P11, the head shell main body <NUM> held to the cylinder <NUM>, and the first fixing screw <NUM> capable of fixing the head shell main body <NUM> to the cylinder <NUM>. The main body holding part <NUM> of the cylinder <NUM> includes the screw guide groove 23b disposed on the external circumferential surface 23a along the axial direction. A part (distal end part <NUM>) of the first fixing screw <NUM> is disposed inside the screw guide groove 23b. In the circumferential direction, spaces G1 and G2 are defined between the first fixing screw <NUM> and the screw guide groove 23b.

With this configuration, movement of the first fixing screw <NUM> in the circumferential direction is restricted to the inside of the screw guide groove 23b. Therefore, the head shell main body <NUM> is rotatable in the circumferential direction with respect to the cylinder <NUM> only in the angle range corresponding to the spaces G1 and G2. By contrast, the head shell main body <NUM> is slidable in the axial direction (front-rear direction) with respect to the cylinder <NUM> by guiding of the first fixing screw <NUM> to the screw guide groove 23b. Specifically, the head shell main body <NUM> is movable only in substantially the axial direction without rotating in the circumferential direction in a large angle range with respect to the cylinder <NUM>. As a result, the user can regulate the position of the needle tip without largely varying the levelness in regulation of overhang. As described above, the head shell <NUM> enables easy and accurate regulation of overhang, in comparison with the conventional head shell.

In addition, the conventional head shell has no groove corresponding to the screw guide groove 23b in the external circumferential surface of the cylinder. By contrast, the head shell <NUM> has a structure of adding (forming) the screw guide groove 23b to the external circumferential surface of the cylinder of the conventional head shell. As a result, the head shell <NUM> facilitates movement of the head shell main body <NUM> in the axial direction while restricting rotation of the head shell main body <NUM> in the circumferential direction. Specifically, the head shell <NUM> enables easy regulation of overhang, only by formation of the screw guide groove 23b corresponding to the first fixing screw <NUM> in the conventional head shell. Specifically, the head shell <NUM> requires no addition of components that may cause unnecessary oscillation. As a result, the productivity of the head shell <NUM> hardly decreases in comparison with the conventional head shell.

In addition, according to the embodiment described above, the distal end surface 50a of the first fixing screw <NUM> can abut against the bottom surface 23b1 of the screw guide groove 23b when the first fixing screw <NUM> is fastened. When the distal end surface 50a abuts against the bottom surface 23b1, the spaces G1 and G2 are still defined. Therefore, when the first fixing screw <NUM> is fastened, the head shell main body <NUM> is fixed to the cylinder <NUM> with the first fixing screw <NUM> without receiving force in the circumferential direction from the first fixing screw <NUM>.

In addition, according to the embodiment described above, the distal end part <NUM> of the first fixing screw <NUM> is disposed inside the screw guide groove 23b. The distal end part <NUM> includes the chamfered surface 50b. Generally, the size (diameter) of the distal end of the screw is not standardized, and tolerance of the size of the distal end is large due to existence of an incomplete thread part or the like. Therefore, the size of the spaces varies in screws having no chamfered surfaces. However, when the chamfered surface 50b is formed in the distal end part <NUM>, a conical surface including no incomplete thread part is formed on the distal end surface 50a side of the distal end part <NUM>. Therefore, variation in size of the spaces G1 and G2 is reduced in the first fixing screw <NUM> having the chamfered surface 50b, in comparison with screws including no chamfered surfaces.

In addition, according to the embodiment described above, the head shell <NUM> includes a regulation assistance mechanism assisting regulation of the position of the head shell main body <NUM> in the circumferential position with respect to the cylinder <NUM>. Therefore, the user can easily regulate the position (levelness of the head shell main body <NUM>) of the head shell main body <NUM> in the circumferential position with respect to the cylinder <NUM> by checking the regulation assistance mechanism by visual observation. That is, the head shell <NUM> enables easy regulation of overhang in comparison with the conventional head shell.

In addition, according to the embodiment described above, the regulation assistant mechanism includes a first sign (projection part <NUM>) and a second sign (regulating groove <NUM>). The cylinder <NUM> includes the first sign, and the head shell main body <NUM> includes the second sign. The second sign is movable with respect to the first sign. Therefore, the user can easily regulate the levelness of the head shell <NUM> by checking the position of the second sign with respect to the first sign by visual observation.

In addition, according to the embodiment described above, the first sign and the second sign can be disposed in line in the radial direction of the cylinder <NUM>. Therefore, the user can easily regulate the levelness of the head shell main body <NUM> by rotating the head shell main body <NUM> such that the first sign and the second sign are aligned in the radial direction by visual observation.

In addition, according to the embodiment described above, the projection part <NUM> used for connection of the connector P11 with the connector part <NUM> functions as the first sign. Therefore, the head shell <NUM> enables regulation of the levelness of the head shell main body <NUM> by user's visual observation, without addition of components that may cause unnecessary oscillation to the conventional head shell.

In addition, according to the embodiment described above, the second sign is disposed on the rear surface 12a of the second holding part <NUM> along the radial direction of the cylinder <NUM>. Therefore, the user can easily regulate the levelness of the head shell main body <NUM> by visually observing the head shell <NUM> from the rear.

In addition, according to the embodiment described above, the second sign is a long groove extending along the radial direction. Therefore, the user can easily regulate the levelness of the head shell main body <NUM> by visual observation by rotating the head shell main body <NUM> to set the center line 121x of the second sign to the central axis 22x of the projection part <NUM>.

As described above, in the head shell <NUM>, rotation of the head shell main body <NUM> is restricted with the distal end part <NUM> disposed inside the screw guide groove 23b. In addition, in the head shell <NUM>, the user can regulate the levelness of the head shell main body <NUM> by checking the position of the regulating groove <NUM> with respect to the projection part <NUM> by visual observation. As a result, the head shell <NUM> enables easy regulation of overhang.

In addition, as described above, the regulating groove <NUM> is a groove extending along the up-down direction, and the screw guide groove 23b is a groove extending along the front-rear direction. The regulating groove <NUM> and the screw guide groove 23b are disposed on the external surfaces (the rear surface 12a and the external circumferential surface 23a) of the head shell <NUM> that are visually observed by the user. Specifically, the regulating groove <NUM> and the screw guide groove 23b appear in the external appearance of the head shell <NUM>, as the two grooves alternating in the up-down direction and the front-rear direction. As a result, the head shell <NUM> gives a prospective consumer of the head shell <NUM> to have an aesthetic impression different from that of the conventional head shell.

It should be noted that the screw guide groove is disposed along the axial direction, and may not disposed at the front end and the rear end of the main body holding part. Specifically, for example, the screw guide groove may be formed with a length approximately half the length of the main body holding part in the axial direction. In this case, in the state in which each of the first fixing screw and the second fixing screw is unfastened, falling of the head shell main body from the cylinder can be prevented.

In addition, in axial view, the circumferential length of the screw guide groove may be equal to or smaller than the external diameter of the first fixing screw.

In addition, in axial view, the circumferential length of the screw guide groove may be larger than the external diameter of the first fixing screw. In this case, for example, even when the distal end part of the first fixing screw includes a complete thread part, the head shell main body is movable only in substantially the axial direction without rotating in a large angle range with respect to the cylinder.

In addition, when the first fixing screw is fastened, the distal end surface of the first fixing screw may not abut against the bottom surface of the screw guide groove. In other words, when the head shell main body is fixed to the cylinder with the first fixing screw, the first fixing screw may abut against the screw guide groove in the circumferential direction. In this case, for example, the spaces are defined when the first fixing screw is unfastened. After regulation of the levelness of the head shell main body, the first fixing screw is fastened to a degree to prevent the head shell main body from moving in the circumferential direction with respect to the cylinder.

In addition, the distal end of the first fixing screw is not limited to a head flat point type. Specifically, for example, the first fixing screw may be a set screw having a various distal end shape, such as a cone point, a round point, a cup point, and a dog point.

In addition, the material of each of the first fixing screw and the second fixing screw is not limited to that of the present embodiment.

In addition, the first fixing screw is not limited to a set screw. Specifically, for example, the first fixing screw may be a bolt including a head part.

In addition, disposition of the first screw hole is not limited to the present embodiment. Specifically, for example, the first screw hole may be disposed in the left side surface or the upper surface of the second holding part. In this case, the screw guide groove is disposed at a position opposed to the first screw hole in the external circumferential surface of the cylinder when the cylinder is inserted through the insertion hole.

In addition, the first sign is not limited to the projection part. Specifically, for example, the terminal pins may function as the first sign. In this case, for example, the user regulates the levelness of the head shell main body by using positional relation between the four terminal pins and the regulating groove as a criterion.

In addition, a groove functioning as the first sign, or a figure or a mark, such as a circle, a polygon, a star-shape, and an arrow, may be disposed on the rear surface of the insulating member. In this case, the cylinder may include the insulating member.

In addition, when the head shell includes no buffer member (or when the buffer member is detached), a groove, a figure, or a mark functioning as the first sign may be disposed on the rear surface of the main body holding part.

In addition, a groove or a recessed part functioning as the first sign may be disposed on the external circumferential surface of the cylinder. Specifically, for example, a long groove having the same width as that of the regulating groove may be disposed on the external circumferential surface of the cylinder along the axial direction. In this case, for example, the user regulates the levelness of the head shell main body while observing the head shell from above.

In addition, the second sign is not limited to the shape extending along the radial direction as long as the second sign serves as a landmark for regulation in the circumferential direction with respect to the first sign. Specifically, for example, the second sign may be a figure or a mark.

In addition, a projecting part functioning as the second sign may be disposed on the rear surface of the second holding part.

In addition, the second sign may not include a recessed part or a projecting part in the rear surface of the second holding part. Specifically, for example, the second sign may be a paint applied to the rear surface, or a sticker put on the rear surface. As another example, the slit of the second holding part may function as the second sign.

In addition, the number of second sign is not limited to one. For example, the second sign may be a plurality of graduations arranged in the circumferential direction.

In addition, the second sign may be disposed on the upper surface of the second holding part. In this case, for example, the user regulates the levelness of the head shell main body while observing the head shell from above.

In addition, the second sign may be disposed on the right side surface of the second holding part. In this case, the screw guide groove functions as the first sign.

In addition, the first sign and the second sign only need to be disposed in line in the radial direction in axial view. Specifically, for example, the first sign and the second sign may be capable of being disposed in line in the right-and-left direction.

In addition, each of the first sign and the second sign may include a straight recessed part or projecting part extending along the front-rear direction in top view. Specifically, for example, the first sign may be disposed in the center of the upper surface of the second holding part in the right-left direction, and the second sign may be disposed on the upper end surface of the holding part.

Claim 1:
A head shell (<NUM>) attachable to and detachable from a connector (P11) of a tone arm (P1) of a record player (P), and holding a pickup cartridge (C), the head shell (<NUM>) comprising:
a cylinder (<NUM>) attachable to and detachable from the connector (P11);
a head shell main body (<NUM>) held to the cylinder (<NUM>) and being rotatable in a circumferential direction of the cylinder (<NUM>) with respect to the cylinder (<NUM>);
a fixing screw (<NUM>) capable of fixing the head shell main body (<NUM>) to the cylinder (<NUM>); the cylinder (<NUM>) includes: a cylindrical cylinder external circumferential surface (23a);a groove (23b) disposed on the cylinder external circumferential surface (23a) along an axial direction of the cylinder (<NUM>);
characterized in that:
a regulation assistance mechanism (<NUM>, <NUM>) configured to assist regulation of a position of the head shell main body (<NUM>) with respect to the cylinder (<NUM>) in the circumferential direction, wherein
the regulation assistance mechanism (<NUM>, <NUM>) includes:
a first sign (<NUM>); and
a second sign (<NUM>) movable with respect to the first sign (<NUM>), wherein the cylinder (<NUM>) includes the first sign (<NUM>),
the head shell main body (<NUM>) includes the second sign (<NUM>), and
a part of the fixing screw (<NUM>) is disposed inside the groove (23b), and
a space (G1, G2) is defined between the fixing screw (<NUM>) and the groove (23b) in the circumferential direction of the cylinder (<NUM>) in such a way that a range of the rotation of the head shell main body (<NUM>) with respect to the cylinder (<NUM>) is restricted by abutment of the fixing screw (<NUM>) against the groove (23b),
the cylinder (<NUM>) includes:
a connector part (<NUM>) attachable to and detachable from the connector (P11); and
a projection part (<NUM>) capable of fixing the connector part (<NUM>) to the connector (P11), and
the projection part (<NUM>) functions as the first sign (<NUM>), wherein the first sign (<NUM>) and the second sign (<NUM>) are configured to assist a user to regulate the position of the head shell main body (<NUM>) in the circumferential position of the cylinder (<NUM>) with respect to the cylinder (<NUM>) by making the first sign (<NUM>) and the second sign (<NUM>) to be disposed in line in a radial direction of the cylinder (<NUM>) in axial view of the cylinder (<NUM>).