TRANSDUCER ELEMENT ASSEMBLY

Abstract: A transducer element assembly comprises a transducer element (2l,) having a scanning surface for scanning a recording surface of a recording medium, a cantilever (ll,) having the transducer element provided on a free tip end thereof and having a pair of holes (l4, l5;) provided on a root end thereof, a support part (l2,) having a pair of generally conical pivots (l7, l8;), and a magnetic coupling mechanism (l3, l9; l3,) provided on the cantilever (ll) and on the support part (l2) for magnetically coupling the two by a magnetic attraction or repulsion. The cantilever (ll) is detachably mounted on the support part (l2) and is user replaceable. When the cantilever (ll) is mounted on the support part (l2), the pivots (l7, l8) engage the corresponding holes (l4, l5) and the cantilever (ll) is rotatable about the root end thereof in a direction approximately perpendicular to the scanning surface of the transducer element. The magnetic attraction or repulsion generated by the magnetic coupling mechanism acts with a predetermined magnitude in a predetermined direction so that the transducer element (ll) makes contact with the recording surfac e of the recording medium with a predetermined contact pressure.

Description: The present invention generally relates to transducer element assemblies, and more particularly to a transducer element assembly having a transducer element for recording and/or reproducing an information signal on and/or from a rotary recording medium. Recently, an information signal is recorded on and reproduced from various recording mediums. As systems in which a transducer element records and/or reproduces the information signal by making direct contact with a recording surface of the recording medium, there are the magnetic recording and/or reproducing system and the electrostatic capacitance type recording and/or reproducing system, for example, and a magnetic head, a reproducing stylus and the like are used as the transducer element. When reproducing the information signal from the rotary recording medium such as a disc, it is necessary to carry out a tracking control so that the transducer element accurately scans over an intended track. The transducer element is provided on a tip end of a cantilever, and a root end of the cantilever is driven and displaced by an actuator so as to displace the transducer element in a direction of the width of the track to thereby carry out the tracking control. A first example of the conventional transducer element assembly comprises a generally V-shaped cantilever and a transducer element provided at the valley part of the V-shaped cantilever. A pair of arms of the cantilever are mounted on a support plate via rubber dampers, and the support plate is driven and displaced by the actuator. The transducer element makes contact with the recording surface of the rotary recording medium with a predetermined contact pressure due to the resiliency of the rubber dampers. Such a transducer element assembly is shown in Fig.l5 of the United States Patent No.4,l60,268, for example. However, according to this first example of the conventional transducer element assembly, there is a problem in that torsion and vibration are easily generated at the transducer element due to the resonance of a mechanical resonant system constituted by the cantilever and the rubber dampers. In addition, when a loop gain of a tracking control system in a recording and/or reproducing apparatus is set to a large gain, there is a possibility of oscillation at high frequencies. Hence, it is possible to consider using rubber dampers having an extremely large stiffness, but in this case, the contact pressure of the transducer element on the recording surface of the rotary recording medium becomes too large. When the contact pressure of the transducer is large, the serviceable life of the transducer element is shortened, and the recording surface of the rotary recording medium is easily damaged. On the other hand, the characteristics of the rubber dampers are unstable with respect to changes in the environment such as the temperature and are subject to deterioration as being aged. Further, the chemical resistance of the rubber dampers is poor. Thus, there is also a problem in that the positioning accuracy of the cantilever with respect to the support plate is poor because of the unstable characteristics of the rubber dampers. A second example of the conventional transducer element assembly comprises a generally triangular cantilever and a transducer element provided on a vertex portion of the triangular cantilever. A pair of conical arms and a permanent magnet are provided on the base portion of the cantilever. A pair of pivots and a permanent magnet are provided on a support plate which is driven and displaced by the actuator. The cantilever is mounted on the support plate so that the pair of conical arms engage corresponding grooves of the pivots on the support plate and the magnet on the cantilever confronts the magnet on the support plate with a gap between the two magnets. Tip ends of the co nical arms are pressed against the corresponding grooves of the pivots due to a magnetic attraction between the two magnets. Such a transducer element assembly is disclosed in the United States Patent No.4,339,8l2, for example. According to the second example of the conventional transducer element assembly, the problems of the first example of the conventional transducer assembly are eliminated because no rubber dampers are used. However, it requires complex processing in order to form the conical arms on the cantilever and to form the grooves of the pivots on the support plate. In addition, the conical arms must be mounted on the cantilever with a high precision so that the conical arms will precisely engage the corresponding grooves of the pivots when the cantilever is mounted on the support plate. As a result, there are problems in that the transducer element assembly has a complex construction and is expensive to manufacture. But since especially the cantilever portion of the transducer element assembly is a disposable type item which is user replaceable, it is desirable that the construction is simple and requires no complex processes to manufacture. Furthermore, it is desirable that the transducer element assembly can be manufactured at a low cost. Accordingly to a first aspect of the invention, there is provided a transducer element assembly as defined in the appended Claim 1. According to a second aspect of the invention, there is provided a transducer element assembly as defined in the appended Claim 23. Preferred embodiments of the invention are defined in the other appended claims. It is thus possible to provide a transducer element assembly comprising a transducer element having a scanning surface for scanning a recording surface of a recording medium, a cantilever having the transducer element provided on a free tip end thereof and having a pair of holes for receiving pivots provided on a root end thereof, a support part driven and displaced by an actuator and having a pair of generally conical pivots, and magnetic coupling means provided on the cantilever and on the support part for magnetically coupling the cantilever and the support part by a magnetic attraction. The cantilever is detachably mounted on the support part and is user replaceable. When the cantilever is mounted on the support part, the pivots of the support part engage the corresponding holes in the cantilever and the cantilever is rotatable about the root end thereof in a direction approximately perpendicular to the scanning surface of the transducer element. The magnetic attraction generated by the magnetic coupling means acts with a predetermined magnitude in a predetermined direction so that the transducer element makes contact with the recording surface of the recording medium with a predetermined contact pressure. Thus the generally conical pivots which require complex processing are provided on the support part which is not user replaceable, and the cantilever which is a disposable type item simply needs to have the holes for engaging the pivots so as to mechanically couple to the support part. Therefore, the construction of the cantilever is simple, and the transducer element assembly can be manufactured at a low cost. It is also possible to provide a transducer element assembly of the type described above which further comprises means for preventing the cantilever from easily disengaging from the support part even when excessive external shock or vibration is applied to the transducer element assembly. It is thus possible to positively prevent an accident in which the cantilever disengages or dislodges from the support part due to excessive external shock or vibration applied to the transducer element assembly. It is further possible to provide a transducer element assembly comprising a transducer element having a scanning surface for scanning a recording surface of a recording medium, a cantilever having the transducer element provided on a free tip end thereof and having a pair of holes for receiving pivots provided on a root end thereof, a support part driven and displaced by an actuator and having a pair of generally conical pivots, and magnetic coupling means provided on the cantilever and on the support part for magnetically coupling the cantilever and the support part by a magnetic repulsion. The cantilever is detachably mounted on the support part, and is user replaceable when the cantilever is mounted on the support part, the pivots of the support part engage the corresponding holes in the cantilever and the cantilever is rotatable about the root end thereof in a direction approximately perpendicular to the scanning surface of the transducer element. The magnetic repulsion generated by the magnetic coupling means acts with a predetermined magnitude in a predetermined direction so that the transducer element makes contact with the recording surface of the recording medium with a predetermined contact pressure. The present invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view from the bottom showing a first embodiment of the transducer element assembly according to the present invention; Figure 2 is an expanded view showing the case where a cantilever shown in Figure 1 is formed from a sheet metal by folding processes; Figures 3A and 3B are a bottom view and a rear view respectively showing the cantilever shown in Figure 1, and Figure 3C is a cross sectional view along a line IIIC-IIIC in Figure 3A; Figures 4 and 5 are perspective views respectively showing second and third embodiments of the transducer element assembly according to the present invention; FIGS.6 and 7 are perspective views respectively showing essential parts of fourth and fifth embodiments of the transducer element assembly according to the present invention; FIG.8 is a perspective view from the bottom showing a sixth embodiment of the transducer element assembly according to the present invention; FIG.9 is an expanded view showing the case where a cantilever shown in FIG.8 is formed from a sheet metal by folding processes; FIGS.l0A and l0B are a bottom view and a rear view respectively showing the cantilever shown in FIG.8, and FIG.l0C is a cross sectional view along a line XC-XC in FIG.l0A; FIGS.ll and l2 are bottom views respectively showing seventh and eighth embodiments of the transducer element assembly according to the present invention; FIG.l3 is a perspective view showing a ninth embodiment of the transducer element assembly according to the present invention; FIGS.l4 through l7A are perspective views respectively showing essential parts of tenth through thirteenth embodiments of the transducer element assembly according to the present invention, and FIG.l7B is a side view showing an essential part of the thirteenth embodiment; FIG.l8 is a perspective view from the bottom showing a fourteenth embodiment of the transducer element assembly according to the present invention; FIG.l9 is a perspective view showing the transducer element assembly according to the present invention together with an actuator of a recording and/or reproducing apparatus; and FIG.20 is a perspective view for explaining the case where the transducer element assembly according to the present invention is applied to the recording and/or reproduction of an information signal with respect to a cylindrical shaped recording medium. FIG.l shows the first embodiment of the invention. A transducer element assembly l0 generally comprises a cantilever ll and a support part l2. The cantilever ll has a generally triangular shape, and has a triangular ope ning lla, a mounting portion llb provided at the base portion of the opening, a rear wall llc, and a mounting portion lld provided at a tip end portion thereof. A permanent magnet l3 is mounted on the mounting portion llb, and a magnetic head 2l is mounted on the mounting portion lld as an example of the transducer element. A pair of holes l4 and l5 for receiving pivots are formed in the rear wall llc. The hole l4 has an elongated shape, and the hole l5 is circular. In the present embodiment, a vibration absorbing layer l6 made of a vibration absorbing agent such as a known adhesive agent which hardens to a rubber form, for example, is formed on a surface of the cantilever ll as indicated by shades. However, the vibration absorbing layer l6 may be omitted. The support part l2 has a pair of generally conical pivots l7 and l8 and a permanent magnet l9. For example, the pivots l7 and l8 are made of stainless steel, ceramics and the like. The support part l2 is connected to an actuator (not shown) which will be described later, and is driven and displaced by the actuator. The cantilever ll is mechanically coupled to the support part l2 when the pivots l7 and l8 of the support part l2 are inserted into the corresponding holes l4 and l5. In this state, the magnets l3 and l9 confront each other with a gap therebetween. Furthermore, since the north and south poles of the magnets l3 and l9 are arranged so that a magnetic attraction is generated between the two magnets l3 and l9, the cantilever ll and the support part l2 are magnetically coupled to each other to thereby maintain the mechanical coupling between the cantilever ll and the support part l2. Accordingly, the cantilever ll is rotatable about the root end thereof (in the vicinity of the rear wall llc) in directions Al and A2 which are approximately perpendicular to the scanning surface of the head 2l. The magnetic attraction generated by magnetic coupling means constituted by the magnets l3 and l9 acts with a predetermined magnitude in a predetermined direction so that the head 2l makes contact with a recording surface of a recording medium (not shown) with a predetermined contact pressure by arranging relative positions of the magnets l3 and l9 and the positions of the pivots l7 and l8 or the holes l4 and l5. It is possible to excite an electromagnet 20 to attract the magnet l3 so as to rotate the cantilever ll in the direction Al. Because the hole l4 has the elongated shape, positional errors introduced in the production between the holes l4 and l5 and the pivots l7 and l8 are absorbed. In addition, by appropriately selecting the sizes of the holes l4 and l5, it is possible to control the gap between the confronting magnets l3 and l9 so as not to make contact with each other yet having a desired magnitude of attraction. According to the present embodiment, the pivots l7 and l8 which require complex processing are provided on the support part l2 which is not user replaceable, and the cantilever ll which is a disposable type item simply needs to have the holes l4 and l5 for engaging the pivots l7 and l8 so as to mechanically couple to the support part l2. Therefore, the construction of the cantilever ll is simple, and the transducer element assembly l0 can be manufactured at a low cost. Moreover, since the cantilever ll is essentially coupled magnetically to the support part l2, the cantilever ll can be detached from the support part l2 for replacement quickly and with ease by pulling the cantilever ll in a direction B against the magnetic attraction generated by the magnetic coupling means. The cantilever ll can be formed by carrying out folding processes on a thin sheet metal which is die-cut as shown in FIG.2. For example, the thickness of the sheet metal is 0.l mm. In FIG.2, the die-cut sheet metal is subjected to folding processes for folding and forming the mounting portions llb and llc, the rear wall llc and side walls lle and llf along phantom lines. FIGS.3A and 3B res pectively show the bottom view and the rear view of the cantilever ll which is formed from such a die-cut sheet metal. FIG.3C shows the cross section of the cantilever ll along the line IIIC-IIIC in FIG.3A. For example, materials such as aluminum, beryllium, titanium and phosphor bronze may be used for the sheet metal. FIG.4 shows the second embodiment of the invention. In FIG.4, those parts which are the same as those corresponding parts in FIG.l are designated by the same reference numerals, and description thereof will be omitted. A transducer element assembly 23 comprises a cantilever 24 and the support part l2. The cantilever 24 comprises a tube 25 having the head 2l provided on a tip end thereof, and a coupling plate 26 fixed to a root end of the tube 25. For example, the tube 25 is made of aluminum. The holes l4 and l5 are formed in the coupling plate 26, and the magnet l3 is fixed to a bottom surface of the coupling plate 26 at such a position that the magnet l3 will confront the magnet l9 with a gap formed therebetween when the cantilever 24 is coupled to the support part l2. FIG.5 shows the third embodiment of the invention. In FIG.5, those parts which are the same as those corresponding parts in FIG.l are designated by the same reference numerals, and description thereof will be omitted. In a transducer element assembly 28 of the present embodiment, the holes l4 and l5 and the magnet l3 are provided on a top surface of a cantilever 29, but the construction of the transducer element assembly 28 is basically the same as that of the first embodiment. FIG.6 shows an essential part of the fourth embodiment of the invention. In FIG.6, those parts which are the same as those corresponding parts in FIG.4 are designated by the same reference numerals, and description thereof will be omitted. In the present embodiment, the construction of a support part l2A and the arrangement of the magnets l3 and l9 are different from the second embodiment. Inverted L-shaped portions 3l and 32 are provided on both sides on a surface l2a of the support part l2A as partially shown in cross section, and the pivots l7 and l8 project toward the surface l2a from the respective inverted L-shaped portions 3l and 32. The north and south poles of the magnets l3 and l9 are arranged so that a magnetic repulsion is generated between the two magnets l3 and l9 when the cantilever 24 is coupled to the support part l2A. Accordingly, the mechanical coupling between the cantilever 24 and the support part l2A is maintained by the magnetic repulsion which urges the coupling plate 26 in a direction away from the surface l2a. According to the present embodiment, the cantilever 24 will not easily disengage from the support part l2A even when excessive external shock or vibration is applied to the transducer element assembly. In addition, the magnetic repulsion generated by magnetic coupling means constituted by the magnets l3 and l9 acts with a predetermined magnitude in a predetermined direction so that the head makes contact with the recording surface of the recording medium with a predetermined contact pressure. FIG.7 shows a support part l2B which constitutes an essential part of the fifth embodiment of the invention. In the present embodiment, the construction of the support part l2B is basically the same as that of the support part l2 described before except that an electromagnet 34 is provided instead of the magnet l9. According to the present embodiment, it is possible to control the contact pressure of the head with respect to the recording surface of the recording medium by controlling a current which is supplied to the electromagnet 34. According to the first, second, third and fifth embodiments described heretofore, the cantilever can be detachably coupled to the support part with ease by using the magnetic attraction generated by the magnetic coupling means. However, the pivots of the support part are simply inserted into the correspon ding holes in the cantilever without having additional means for interlocking the cantilever and the support part. For this reason, when excessive external shock or vibration is applied to the transducer element assembly, the cantilever may disengage from the support part. The problem may be lessened by enlarging the holes in the cantilever, but in this case, the cantilever will not be able to rotate smoothly. On the other hand, according to the fourth embodiment, the cantilever will not easily disengage from the support part even when excessive external shock or vibration is applied to the transducer element assembly. However, since the fourth embodiment uses magnetic repulsion, the cantilever must be coupled to the support part against the magnetic repulsion when engaging the holes to the corresponding pivots. For this reason, the cantilever cannot be attached to and detached from the support part as easily as in the case of the first, second, third and fifth embodiments. Next, description will be given with respect to embodiments in which the cantilever can be attached to and detached from the support part with ease, and the transducer element assembly is further provided with means for preventing unwanted disengagement of the cantilever from the support part due to excessive external shock or vibration applied thereto. FIG.8 shows the sixth embodiment of the invention. A transducer element assembly 40 generally comprises a cantilever 4l and a support part 42. The cantilever 4l has a generally triangular shape, and has side walls 4la and 4lb, a triangular opening 4lc, a mounting portion 4ld provided in a vicinity of the base portion of the triangular opening 4lc, and a mounting portion 4le provided at a tip end portion thereof. As will be described later in conjunction with FIG.l0C, the cantilever 4l has a bend at an intermediate portion thereof. A permanent magnet 43 is mounted on the mounting portion 4ld by a pin 44, and a magnetic head 45 is mounted on the mounting portion 4le as an example of the transducer element. A circular hole 46 for receiving a pivot is formed in the side wall 4la and an elongated hole 47 for receiving a pivot is formed in the side wall 4lb, respectively at the root end of the cantilever 4l. The elongated hole 47 has a V-shape and is open on one end thereof. In the present embodiment and the embodiments which will be described later, the illustration of a vibration absorbing layer is omitted. However, it is of course possible to form the vibration absorbing layer on a surface of the cantilever as in the case of the first embodiment shown in FIG.l. Generally conical pivots 48 and 49 are respectively provided on side surfaces 42a and 42b of the support part 42, and the pivots 48 and 49 project in directions perpendicular to the respective side surfaces 42a and 42b. A permanent magnet 50 is provided on a front surface 42c of the support part 42. The support part 42 is driven and displaced by the actuator which will be described later. The cantilever 4l is mechanically coupled to the support part 42 by first inserting the pivot 48 of the support part 42 into the corresponding hole 46 and next inserting the pivot 49 into the corresponding hole 47. In this state, the magnets 43 and 50 confront each other with a gap therebetween. Furthermore, since the north and south poles of the magnets 43 and 50 are arranged so that a magnetic attraction is generated between the two magnets 43 and 50, the cantilever 4l and the support part 42 are magnetically coupled to each other to thereby maintain the mechanical coupling between the cantilever 4l and the support part 42. Accordingly, the cantilever 4l is rotatable about the root end thereof (in the vicinity of the holes 46 and 47) in directions Al and A2 which are approximately perpendicular to the scanning surface of the head 45. The magnetic attraction generated by magnetic coupling means constituted by the magnets 43 and 50 acts with a predetermined magnitude in a predetermined direction so that the head 45 makes contact with a recording surface of a recording medium (not shown) with a predetermined contact pressure. Since the hole 47 is open to the rear end of the side wall 4lb, positional errors introduced in the production between the holes 46 and 47 and the pivots 48 and 49 are absorbed. According to the present embodiment, the cantilever 4l is supported at the sides thereof. Hence, in addition to the advantageous effects obtained in the first embodiment and the like, there is a further advantage in that the cantilever 4l will not easily disengage from the support part 42 even when excessive external shock or vibration is applied to the transducer element assembly 40. Particularly, the cantilever 4l will not disengage from the support part 42 when a force acts on the cantilever 4l to pull the cantilever 4l in the direction B. The cantilever 4l can be detached from the support part 42 quickly and easily by first disengaging the pivot 49 from the hole 47 by pulling the cantilever 4l in a direction Y and then pulling the cantilever 4l in a direction C in which the pivot 48 generally extends. The cantilever 4l can be formed by carrying out folding processes on a thin sheet metal which is die-cut as shown in FIG.9, similarly as in the case shown in FIG.2. For example, the thickness of the sheet metal is in the order of 0.l mm. In FIG.9, the die-cut sheet metal is subjected to folding processes for folding and forming the side walls 4la and 4lb, the mounting portions 4ld and 4le, and the bend described before along phantom lines. FIGS.l0A and l0B respectively show the bottom view and the rear view of the cantilever 4l which is formed from such a die-cut sheet metal. FIG.l0C shows the cross section of the cantilever 4l along the line XC-XC in FIG.l0A. FIG.ll shows the seventh embodiment of the invention. In FIG.ll, those parts which are the same as those corresponding parts in FIG.8 are designated by the same reference numerals, and description thereof will be omitted. The present embodiment is basically the same as the sixth embodiment except that the magnet 50 is mounted at a position deviated toward the pivot 49 from the position perfectly confronting the magnet 43. According to a transducer element assembly 40A shown in FIG.ll, the cantilever 4lA is also urged in a direction D due to the magnetic attraction between the two magnets 43 and 50. As a result, the cantilever 4lA can be coupled more positively to the support part 42, and the unwanted disengagement of the cantilever 4lA from the support part 42 due to excessive external shock or vibration is more positively prevented. FIG.l2 shows the eighth embodiment of the invention. In FIG.l2, those parts which are the same as those corresponding parts in FIG.8 are designated by the same reference numerals, and description thereof will be omitted. In the present embodiment, a cantilever 4lB of a transducer element assembly 52 has side wall portions 4lal and 4lbl at the root end thereof. The side wall portions 4lal and 4lbl are approximately parallel to each other, and the holes 46 and 47 are formed in the side wall portions 4lal and 4lbl, respectively. In addition, the side surfaces 42a and 42b of a support 42B are also approximately parallel to each other, and are approximately parallel to the corresponding and confronting side wall portions 4lal and 4lbl of the cantilever 4lB. The pivots 48 and 49 project approximately perpendicularly from the respective side surfaces 42a and 42b. FIG.l3 shows the ninth embodiment of the invention. In FIG.l3, those parts which are the same as those corresponding parts in FIG.8 are designated by the same reference numerals, and description thereof will be omitted. A transducer element assembly 54 comprises a cantilever 55 and a support part 56. The cantilever 55 comprises a tube 57 having the head 45 provided on a tip end thereof, and a coupling member 58 fixed to the root end of the tube 57. The c oupling member 58 has a generally U-shape and has side wall portions 58a and 58b, and the holes 46 and 47 are formed in the respective side wall portions 58a and 58b. The magnet 43 is mounted on a bottom surface of the coupling member 58 at such a position that the magnet 43 confronts the magnet 50 with a gap formed therebetween when the cantilever 55 is coupled to the support part 56. On the other hand, the support part 56 has a generally U-shape and has side wall portions 56a and 56b. The pivots 48 and 49 are provided on the respective side wall portions 56a and 56b so as to confront each other. The magnet 50 is mounted on a front surface 56c of the support part 56. The cantilever 55 is coupled to the support part 56 by fitting the coupling member 58 into the U-shape of the support part 56 so that the pivots 48 and 49 engage the corresponding holes 46 and 47. FIG.l4 shows a cantilever 4lC which constitutes an essential part of the tenth embodiment of the invention. In the present embodiment, the cantilever 4lC differs from that of the sixth embodiment in that an elongated V-shaped hole 47C formed in the side wall 4lb of the cantilever 4lC is open generally to the rear end but is inclined with respect to a generally longitudinal direction of the cantilever 4lC. The cantilever 4lC may be used with either one of the support parts shown in FIGS.8 and l3. FIGS.l5 through l7 show essential parts of the eleventh through thirteenth embodiments of the invention, respectively. In the eleventh embodiment shown in FIG.l5, at least one of the pivots (the pivot 48 in FIG.l5) is slidable in a direction generally perpendicular to the side surface 42a of the support part 42 as partially shown in cross section. In addition, the one pivot 48 is loaded with a coil spring 60 and is constantly urged to the outside in the direction generally perpendicular to the side surface 42a. Furthermore, the holes 46 and 6l formed in the side walls 4la and 4lb of the cantilever are both circular. The cantilever is coupled to the support part 42 by compressing the coil spring 60 and engaging the pivots 48 and 49 to the corresponding holes 46 and 6l. In the twelfth embodiment shown in FIG.l6, the holes 46 and 6l formed in the side walls 4la and 4lb of the cantilever are both circular. However, at least one of the side walls 4la and 4lb has a leaf spring structure and is resiliently deformable. Hence, the cantilever is coupled to the support part 42 by resiliently deforming the side walls 4la and/or 4lb and engaging the pivots 48 and 49 to the corresponding holes 46 and 6l. In FIGS.l5 and l6, one of the two holes, that is, the hole 6l, for example, may be made larger than the other hole 46. In this case, positional errors introduced in the production between the holes 46 and 6l and the pivots 48 and 49 are absorbed. According to the eleventh and twelfth embodiments, the cantilever will not easily disengage from the support part even when excessive external shock or vibration is applied to the transducer element assembly. In the thirteenth embodiment shown in FIGS.l7A and l7B, a hole 62 formed in the side wall 4lb of the cantilever has a generally L-shape one leg of which is extending toward a front of the cantilever and another leg is open to an edge of the side wall 4la. The one leg extending toward the front may have an arrow shape pointing the front for secure engagement with the pivot 80 as shown in FIG.l7B. For this reason, the cantilever will not easily disengage from the support part even when excessive external shock or vibration is applied to the transducer element assembly. FIG.l8 shows the fourteenth embodiment of the invention. A transducer element assembly 70 generally comprises a cantilever 7l and a support part 72. The cantilever 7l has a generally triangular shape, and a pair of holes 73 (only one shown) for receiving pivots are formed in side walls at the root end thereof. The hole 73 which is not show n has a circular shape, and the hole 73 which is shown has a generally L-shape. A permanent magnet 74 is fixed to a front surface of a rear wall of the cantilever 7l. A hole 75 is formed in a front wall of the cantilever 7l, and a rotatable rod 76 which extends from the magnet 74 penetrates the front wall of the cantilever 7l through the hole 75. A transducer element supporting member 77 is fixed to a tip end of the rod 76 in a T-shape, and a magnetic head 78 and a reproducing stylus 79 are fixed to respective ends of the supporting member 77. The reproducing stylus 79 is an electrostatic capacitance type reproducing stylus. A pair of generally conical pivots 80 (only one shown) are provided on both sides of the support part 72. The pivots 80 project in a direction approximately perpendicular to the side walls of the cantilever 7l. A permanent magnet 8l is fixed to a front surface of the support part 72. The cantilever 7l is mechanically coupled to the support part 72 by inserting the pivots 80 into the respective holes 73. In this state, the magnets 74 and 8l confront each other via the rear wall of the cantilever 7l and a gap formed between the magnets 74 and 8l. The north and south poles of the magnets 74 and 8l are arranged so that a magnetic attraction is generated between the magnets 74 and 8l. Accordingly, the cantilever 7l and the support part 72 are coupled magnetically by the magnetic attraction, and the above described mechanical coupling is maintained. In addition, as in the case of the embodiments described heretofore, the contact pressure of the head 78 and the reproducing stylus 79 with respect to a recording surface of a recording medium (not shown) can be appropriately set by the magnetic attraction. In the embodiments described heretofore, a combination comprising a pair of permanent magnets or a combination comprising an electromagnet and a permanent magnet is used as the magnetic coupling means. However, the magnetic coupling means is not limited to these combinations, and for example, a combination comprising a permanent magnet or an electromagnet and a metal part attracted thereby may be used when obtaining the magnetic attraction. In addition, the transducer element is not limited to the magnetic head and the electrostatic capacitance type reproducing stylus. Next, description will be given with respect to the connection of the transducer element assembly according to the present invention and the actuator, by referring to FIG.l9. For convenience' sake, the transducer element assembly 40 shown in FIG.8 will be used as the transducer element assembly. The construction of an actuator 89 itself is known. A frame member 90 is formed by bending a magnetic material into a substantially U-shape. Permanent magnets 9l and 92 are fixed to inner sides of arm portions of the frame member 90, and a U-shaped yoke 93 is fixed on the base part of the frame member 90 between the magnets 9l and 92. A moving body 94 comprises a pair of coils 95 and 96 wound in a rectangular form. Each of the coils 95 and 96 respectively are adjacent to a stiff support plate 97 and are fixed thereto. A leaf spring 98 made of phosphor bronze, for example, is provided across between tip ends of the arm portions of the frame member 90, in a state where both sides of the leaf spring 98 are respectively supported by rubber supports 99 and l00. A pair of connecting members l0l and l02 respectively having one end thereof fixed to the support plate 97, penetrate through a pair of openings provided in the leaf spring 98. The connecting members l0l and l02 respectively have the other end thereof fixed to the rear surface of the support part 42. Terminals of the head 45 are electrically coupled to a recording and/or reproducing apparatus (not shown) by inserting a plug l05 into a socket l06 which is provided on the frame member 90. Wires l04 from the terminals of the head 45 are coupled to the plug l05 via a buffer circuit l03 provided on the cantil ever 4l. The displacement of the moving body 94 responsive to a control signal current is accurately transmitted to the support part 42 via the connecting members l0l and l02, and the head 45 is thereby displaced in a direction X and the tracking control operation is accurately carried out. Next, description will be given with respect to the application of the transducer element assembly according to the present invention to the recording and/or reproduction of an information signal on and/or from a cylindrical recording medium, by referring to FIG. 20. For convenience' sake, it will be assumed that the combination of the transducer element assembly 40 and the actuator 89 shown in FIG. 19 is used. A recording medium driving part of the apparatus comprises a recording medium support 110, a motor 111, and a motor housing 112. A cylindrical recording medium 113 which is placed on the support 110 is rotated by the motor 111. A carriage driving part of the apparatus comprises a feed screw 115, and a motor 117 which rotates the feed screw 115 via a reduction gear 116. A carriage 118 is guided by a guide rod 119 and is moved upwardly and downwardly by the rotation of the feed screw 115. The actuator 89 is fixed to the carriage 118. Accordingly, the head 45 moves along a magnetic recording surface of the cylindrical recording medium 113 and forms closed loop tracks on the magnetic recording surface. The recording medium which is used to carry out the recording and/or reproduction of the information signal is not limited to the cylindrical recording medium, and it is possible to use any rotary recording medium such as a disc. Moreover, the support part of the transducer element assembly may be connected directly to the carriage of the recording and/or reproducing apparatus.

Claims: A transducer element assembly comprising at least one transducer element having a scanning surface for scanning a recording surface of a recording medium, a cantilever having the transducer element provided on a distal free end thereof, a support part, and magnetic coupling means provided on the cantilever and the support part for magnetically coupling the cantilever and the support part by a magnetic attraction, said cantilever being detachably coupled to said support part and being rotatable about a root end thereof in a direction approximately perpendicular to the scanning surface of the transducer element, and said magnetic attraction generated by said magnetic coupling means acting with a predetermined magnitude in a predetermined direction so that said transducer element makes contact with the recording surface of the recording medium with a predetermined contact pressure, characterised in that said cantilever (11, 24, 29, 41, 41A, 41B, 55, 41C, 71) has a pair of holes (14, 15; 46, 47; 46, 47C; 46, 61; 46, 62; 73) for receiving pivots formed at the root end thereof; said support part (12, 12A, 12B, 42, 42B, 56, 72) has a pair of generally conical pivots (17, 18; 48, 49; 80); and said pivots of the support part are engaged with the corresponding holes in the cantilever when the cantilever is coupled to the support part. A transducer element assembly as claimed in Claim 1, characterised in that said holes (14, 15) in the cantilever are formed side by side at the root end thereof. A transducer element assembly as claimed in claim 2, characterized in that one (15) of said holes (14, 15) has a generally circular shape and the other (14) of said holes has a shape elongated along a direction of an imaginary line connecting said holes. A transducer element assembly as claimed in claim 2, characterized in that said cantilever (11) has a generally triangular shape, said transducer element being provided on the cantilever at a vertex portion of the triangular shape, said holes (l4, l5) being formed in a rear wall (11c) of the cantilever at a base portion of the triangular shape. A transducer element assembly as claimed in claim 2, characterized in that said cantilever (29) has a generally triangular shape, said transducer element being provided on the cantilever at a vertex portion of the triangular shape, said holes (14, 15) being formed in a top surface of the cantilever at a base portion of the triangular shape. A transducer element assembly as claimed in claim 2, characterized in that said cantilever (24) has a generally T-shape. A transducer element assembly as claimed in claim 6, characterized in that said cantilever (24) comprises a pipe member (25) having the transducer element provided on a tip end thereof and a coupling member (26) having a central part thereof fixed to a root end of said pipe member to form a T-shape with said pipe member, said holes (14, 15) being formed in said coupling member. A transducer element assembly as claimed in claim l, characterized in that said holes (46, 47; 46, 47C; 46, 61; 46, 62; 73) in the cantilever are formed confronting each other at the root end thereof. A transducer element assembly as claimed in claim 8, characterized in that one (46) of said holes (46, 47; 46, 47C; 46, 62; 73) has a generally circular shape and the other (47, 47C, 62, 73) of said holes has an open end. A transducer element assembly as claimed in claim 9, characterized in that said other (47, 47C) of said holes has a generally V-shape. A transducer element assembly as claimed in claim 9, characterized in that said other (62, 73) of said holes has a generally L-shape. A transducer element assembly as claimed in claim 8, characterized in that said cantilever (41, 41A, 41B, 41C, 71) has a generally triangular shape, said transducer element being provided on the cantilever at a vertex portion of the triangular shape, said holes (46, 47; 46, 47C; 46, 61; 46, 62; 73) being formed in side walls (41a, 41b) of the cantilever at a base portion of the triangular shape. A transducer element assembly as claimed in claim 12, characterized in that said support part (42, 42B) has side surfaces (42a, 42b) which are approximately parallel to said side walls (41a, 41b) of the cantilever, said pivots (48, 49, 80) being provided on said side surfaces of the support part and projecting approximately perpendicularly to said side surfaces. A transducer element assembly as claimed in claim 12, characterized in that said side walls (41a, 41b) of the cantilever (41B) have side wall portions (41a1, 41b1) which are approximately parallel to each other at the root end of the cantilever. A transducer element assembly as claimed in claim 12, characterized in that each of said holes (46, 61) have a circular shape, at least one of said side walls (41a, 41b) of the cantilever being resiliently deformable in a vicinity of said holes. A transducer element assembly as claimed in claim 12, characterized in that each of said holes (46, 61) have a circular shape, at least one (48) of said pivots being loaded with a coil spring (60) which urges the pivot in a direction so as to engage a corresponding one (46) of said holes. A transducer element assembly as claimed in claim 8, characterized in that said cantilever (55) comprises a pipe member (57) having the transducer element provided on a tip end thereof and a coupling member (58) having a central part thereof fixed to a root end of said pipe member to form a T-shape with said pipe member, said holes (46, 47) being formed in side wall portions said coupling member. A transducer element assembly as claimed in claim 1, characterized in that said magnetic coupling means comprises a pair of permanent magnets (13, 19; 43, 50; 74, 81) respectively provided at the root end of said cantilever and on said support part so as to confront each other with a gap formed between the two permanent magnets. A transducer element assembly as claimed in claim 18, characterized in that one (46) of said holes (46, 47; 46, 47C; 46, 62; 73) has a generally circular shape and the other (47, 47C, 62, 73) of said holes has an open end, said pair of permanent magnets (43, 50) being provided at positions deviated along a generally projecting direction of one (48) of said pivots so that said magnetic attraction also acts in a direction urging said one pivot to engage with said one hole. A transducer element assembly as claimed in claim 1, characterized in that said magnetic coupling means comprises a permanent magnet (13, 43, 74) provided at the root end of said cantilever and an electromagnet (34) provided on said support part so as to confront each other with a gap formed between said permanent magnet and said electromagnet. A transducer element assembly as claimed in claim 1, characterized in that said cantilever is provided with a vibration absorbing layer (16) on a surface thereof. A transducer element assembly as claimed in claim 1 in which said support part is driven and displaced by moving means. A transducer element assembly comprising at least one transducer element having a scanning surface for scanning a recording surface of a recording medium, a cantilever having the transducer element provided on a distal free end thereof, a support part, and magnetic coupling means for magnetically coupling the cantilever and the support part, said cantilever being detachably coupled to said support part and being rotatable about a root end thereof in a direction approximately perpendicular to the scanning surface of the transducer element, said magnetic force generated by said magnetic coupling means acting with a predetermined magnitude in a predetermined direction so that said transducer element makes contact with the recording surface of the recording medium with a predetermined contact pressure, characterised in that said cantilever (24) has a pair of holes (14, 15) for receiving pivots formed at a root end thereof; said support part (12A) has a pair of generally conical pivots (17, 18); said magnetic coupling means (13, 19) generates said magnetic force as a magnetic repulsion; and said pivots of the support part are engaged with the corresponding holes in the cantilever when the cantilever is coupled to the support part. A transducer element assembly as claimed in Claim 23 in which said support part is driven and displaced by moving means.

Inventors: KINJO, HISAO
Applicants: VICTOR COMPANY OF JAPAN, LIMITED
Application year: 1986
Main classification: G11B3
IPC codes: G11B21, G11B5