KR840002522Y1 - Head-drum mounting for a helical scan tape recorder - Google Patents

Abstract

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Description

Magnetic recording and reading device for broadband signals

1 is a perspective view of a helical scanning video tape recorder having a rotating open cassette holder capable of supporting a magnetic tape cassette.

FIG. 2 is a slightly enlarged perspective view of a portion of the video cassette recorder of FIG. 1 with the cassette holder removed from another angle.

3 is an enlarged side and cross sectional view of the enlarged drum unit showing a rotatable head drum device having a stationary cylindrical tape guide drum and a cylindrical head drum of the video cassette recorders of FIGS. 1 and 2;

4 is a perspective view of a retaining ring used in the head drum of FIG. 3 to fix and center the head drum on the drive spindles of a video cassette recorder.

5 and 6 are perspective views of a simple auxiliary tool part for mounting the retaining ring of FIG.

FIG. 7 is a perspective view and an exploded part arrangement view showing a simple auxiliary tool for moving the retaining ring of FIG. 4. FIG.

FIG. 8 is a schematic drawing of a diaphragm used in the headdral device of FIG. 3 to center the device on the second side of a simple auxiliary tool.

FIG. 9 is a cross sectional view of the diaphragm of FIG. 8 cut along an arrow Ⅸ-Ⅸ. FIG.

10 is a front view of the compression member used to mount the diaphragm of FIG.

FIG. 11 is a cross sectional view of the compression member of FIG. 10 cut along arrow XI-XI. FIG.

12 is a cross-sectional view of a head drum device according to another embodiment of the present invention.

FIG. 13 is a cross sectional view of a compression bush used in the head drum device of FIG.

14 is a cross-sectional view of another compression bush used in the head drum device of FIG.

FIG. 15 is a front view of the compression bush of FIG.

FIG. 16 is a front elevational view of a part of the head drum device of FIG. 12 having three tension members for transmitting a pulling force between two compression bushes of FIGS. 13, 14, and 15, respectively.

FIG. 17 is a cross sectional view of a part of FIG. 16 cut along an arrow (XVII-XVII). FIG.

18 is a schematic cross-sectional view showing the principle of a head drum for a device of another embodiment of the present invention.

19 is a schematic cross sectional view showing the principle of a headdrel for another embodiment of the present invention.

The present invention relates to a device for recording and reading a wideband signal on a magnetic tape of signal tracks that are adjacent to and obliquely extending to each other. The device has a free end, cylindrical drive spindles around a rotating shaft, and an inclination signal on a magnetic tape. Record and read tracks, detachably secured to the cylindrical part of the drive spins near the free end and at least one magnetic head rotating in an annular line around the axis of rotation, the first side and the free end spaced apart from the free end A head drum system on the drive spindles, the head drum system being positioned on the first side of the head drum system and the head drum system having a second side formed therein and having a central hole for moving the magnetic head and mounting the head drum device on the drive spindles. Centered on the first side of the head drum device and cooperating with the drive spindles It made of set apparatus and the like can be made as part wall.

A device for magnetically recording and reading such video signals, ie spiral scanning video recorders, is known from the specification of Austrian patent AT-PS 345577. In this known apparatus, the head drum system is a coaxial with the rotating drum and a cylindrical head drum for guiding the magnetic tape by forming a rotating unit of the drum unit and connecting to the magnetic head of the spiral line, and as much as a narrow gap with the rotating drum. It consists of a spaced drum that is spaced apart. On the stationary drum, a spiral guide edge for magnetic tape extends over the entire circumference of the stationary drum. As the head drum rotates, a thin film of air is locally produced between the magnetic tape and the drum unit, reducing friction between the magnetic tape and the drum unit. On the first side of the head drum, which is spaced apart from the stationary drum, a fixed sleeve having a cylindrical outer surface is installed. The wall of the fixed sleeve is elastically deformable, and a fixed slot is formed in the ring wall around the fixed sleeve. The ring is mounted so that the fixed ring portions separated by the slots can move elastically toward each other. The screw bolts are mated in the retaining ring to one side of the slot and extend through the retaining ring with clearance to the other side of the slot. Tightening the bolt deforms the retaining ring, which deforms the retaining sleeve of the head drum and fixes the head drum centered on the drive spindles. In video recorders, particularly cassette recorders for home entertainment, the most economical use of magnetic tapes is sought, and therefore, it has been attempted to provide magnetic tapes in a form in which the adjacent signal tracks are as compact as possible. Current spiral scan video cassette recorders utilize a slightly nested signal track with a width of about 40 microns and a center spacing of about 30 microns. The track length is about 100mm. The track must be located in narrow tolerances throughout its length. This is because it is particularly valuable for the possibility of reproducing a video program recorded by another similar video recorder with one video recorder without loss of quality. Compatibility of cassettes with recorded programs and video recorders belonging to the standard system for recording / reproducing video signals is obtained only in the following cases. In other words, a program recorded in one video cassette recorder can be reproduced by another video cassette recorder belonging to the same video recorder system without sacrificing playback signal quality. This requirement is said to be compatible with magnetic tape cassettes for recording and playback video signals belonging to video recorders and related standard systems. As a result, a very small tolerance range applies to the position of the magnetic head relative to the tape guide stop. In a spiral scan video cassette recorder having a plurality of magnetic heads, such as a video cassette recorder configured for home use, it is important to arrange the heads accurately with each other in terms of synchronizing video signals recorded and read by the head. In this case, too, a small tolerance range is applied, because if the tolerance range is not small, a visible time error occurs in the reproduced video image. In other words, the edge of the image becomes unstable.

In response to the demand for strict precision on the position of magnetic heads, special optical precision instruments are used for depositing magnetic heads in the head drum apparatus. In the case of the head drum device of a known type, the head drum device is first centered and mounted on a special mounting spindle by a self-calibrating device. After the magnetic head is mounted and arranged, the head drum device will be separated from the mounting spindle by relaxing the fixing device and then the head drum device will be mounted on the drive spindles of the video cassette recorder. The adjustment performed by the mounting spindles is most accurately reproduced after the head drum device is mounted on the drive spindles of the video cassette recorder. In recent spiral scan video cassette recorders, the height tolerance of the magnetic head relative to the tape guide edge is adjusted to a size of 5 microns so that the mutual height difference between the magnetic heads should not exceed 5 microns. In a head drum device having a diameter of 65 mm and consisting of a rotating head drum for moving two magnetic heads, the eccentricity of the magnetic head relative to the axis of rotation of the head drum in the actual video cassette recorder is less than 1 1/2 micron. Another requirement that is added is that the magnetic heads are spaced on the circumference of the head drum device accurately and uniformly. That is, when two magnetic heads are used, the length of the arc between the two magnetic heads should not differ by more than 3 microns from each other.

The construction of the head drum device must be such that attachment and detachment of the head drum device can be done quickly using simple means during the manufacture of the video cassette recorder or during any service. If the head drum device is removed and then a new head drum device is attached, i. E. Serviced, the desired compatibility shall be ensured. The head drum must be precisely centered and precisely coaxially mounted within the tolerance zone in view of the very small tolerances that can be tolerated with respect to the position of the eccentricity and height of the magnetic head. Such centering and mounting operations can be performed quickly by a service engineer without the use of special arrangements.

The center hole of the known head drum has any length. The diameter of the ball is slightly larger than the diameter of the drive spindles. The radial small gap between the drive spindle and the wall of the center hole makes it easy to slide the head drum onto the drive spindles. After the head drum device is inserted onto the drive spindle, the head drum device is fixed to the drive shaft by the fixing device. Any inclination of the head drum device relative to the axis of rotation is inevitable in that the gap between the wall of the center hole and the drive spindle is locally removed at the position of the fixing device by the elastic deformation of the fixing sleeve. By the applied clamping force, the gap between the drive spindle of the head drum device and the wall of the ball is completely eliminated on one side of the ball. This inclination is undesirable because it contributes to the eccentricity of the magnetic head and causes an error in the position of the support head relative to the support edge. The position at which the drive spindle is in contact with the ball on the second side of the head drum device is unpredictable and nonreproducible. Thus, the inclination direction with respect to the head drum device which occurs during the mounting of the special mounting spindle is different from the inclination direction with respect to the head drum device which occurs while being mounted on the drive spin of the video cassette recorder.

It is an object of the present invention to provide a device for magnetic recording and reading of a wideband signal, on which at least one magnetic head can be reproduced in its original arrangement when the head drum device is mounted on a drive spindle of a video recorder. It is.

The present invention provides two centrally spaced apart laterally centering devices for centering a head drum system on a drive spin stone on both sides, namely a head drum system, a first centering device on a first side and a second side lift. A first elastically deformable wall portion cooperating with the second centering device and the drive spindle of the head and forming part of the centering device on the first side of the head drum device, the second spindle of the head drum device And a second elastic deformable wall portion forming part of the centering device on the side.

By using the two centering devices on both sides of the head drum device, a head drum device having a reduced inclination with respect to the rotation axis is obtained.

The first embodiment of the present invention is characterized in that the first central setting device is a first fixing device which is centered by detachably fixing the head drum system on the driving spindle, wherein the first fixing device is connected to the driving spindle. Cooperate with a first elastically deformable wall portion and a first elastically deformable wall portion of the cooperating first centering device, and apply pressure on the first elastically deformable wall portion to not only elastically deform the wall portion, but also on the drive spindle. And a wall deforming device for centering and fixing the head drum device, wherein the second elastically deformable wall portion on the second side of the head drum system includes a centering plate made of an elastic wallboard material. And the diaphragm forms a central opening for fitting the driving spindle tightly to the driving spindle portion of the centering diaphragm adjacent to the central opening. The head drum device mounted on the powder phase has a shape and a size that can be elastically deformed in the axial direction by a force obtained between the centering plate and the drive spindle, and the fixing means for fixing the centering plate has a center opening. The portion of the centering diaphragm located between the center opening and the position in which the fastening means cooperates with the centering diaphragm because it cooperates with the centering diaphragm at a constant distance from is characterized in that it is free of a certain size to be elastically deformable. The use of a centering plate to center the head drum is already proposed in US Pat. No. 4,321,639. This embodiment is characterized in that the first deformable wall portion has an elastically deformable fixed sleeve concentric with the drive spindle, the sleeve having a free end and an outer circumferential surface, the wall deforming device having an outer circumferential surface of the fixed sleeve. It is characterized by including the fixed sleeve deformation | transformation apparatus which applies pressure to a phase.

In this embodiment, the fixing device on the first side of the head drum consists of a fixing device known from the specification of Austrian patent AT-PS 345,577. However, the stationary sleeve deformer has a stationary ring that deforms between a relaxed position and a stationary position, wherein the stationary ring has a continuous structure in the conical direction and is concentric on the circumference of the stationary sleeve by local symmetrical radial deformation. Characterized by applying an evenly distributed fixation force, the retaining ring having a conical inner wall with a surface forming a masking portion of the imaginary cone, the imaginary cone having a right angle between the biaxial and the masking face. And the fixed ring is moved from the relaxed position to the fixed position by being axially moved through the fixed sleeve in cooperation with a portion of the outer circumferential surface of the fixed sleeve, wherein the right angle is used for the fixed sleeve. The frictional force generated between the fixed sleeve and the fixed ring is smaller than the friction angle between the material used and the material used for the fixed ring. It is advantageous to use an embodiment wherein the axial component of the holding force acting on the holding ring in the tooth prevents the holding ring in the holding position from being returned to the relaxed position. The fixing device on the first side of the head drum being used in this embodiment has been proposed by known techniques.

The retaining sleeve may have a shoulder on the outside, the shoulder being concentric with the axis of rotation of the drive spindles and in cooperation with the conical inner wall of the retaining ring, the retaining sleeve is deformed by the retaining ring at a position exactly defined by the shoulder. The head drum system may have a joint coaxial with the stationary sleeve which receives the pressure exerted on the head drum device by an auxiliary tool that provides the axial movement through the stationary sleeve.

A second embodiment of the present invention is a fastening device for removably centering a head drum device on a drive spindle by means of a first centering device, and the first centering device of the first centering device which cooperates with the drive spindle. 1 cooperative with the elastically deflectable wall portion and the first elastically deformable wall portion, applying pressure on the first elastically deformable wall portion to elastically deform the wall portion as well as centering and fixing the head drum device on the drive spindle. And a wall deforming device for acting, wherein a second centering device on the second side of the head drum system is a second fixing device for removably centering the head drum device on the drive spindle. The second fixing device cooperates with the second elastically deformable wall portion and the second elastically deformable wall portion of the second centering device that cooperate with the drive spindle. By applying pressure on the elastically deformable wall portion, it is characterized by consisting of a wall deforming device that acts to not only elastically deform the wall portion but also to fix and fix the head drum device on the drive spindle. In this embodiment, two fasteners are provided to secure the head drum system on the drive spindle, so that each fastener requires only half of the total fastening force required. In a video recorder, the second side of the head drum device is at a very small distance from the stop drum, so in a preferred embodiment at least one opening in which the head drum system extends from the first side of the head drum system to the second side. The second fixing device can be moved from the relaxed position to the fixed position or the reverse direction from the first side of the head drum device through the opening, thereby eliminating assembly problems.

In a third embodiment of the present invention, the first, second, and elastically deformable wall portions have a second cylindrical fixing sleeve, respectively concentric with the circumferential portions of the drive spindles and having a free end. The first and second wall deforming devices are provided with first and second fixing rings which are concentrically matched with the first and second fixing sleeves and which are radially deformed between the relaxed and fixed positions by being axially compressed. And the first and second wall deforming devices are arranged concentrically around the first and second fixing sleeves except for the annular space for the first and second fixing rings. Wherein the axially movable compressor cooperates with the first and second fixing rings to axially compress the fixing ring, the first and second fixing rings from the free ends of the first and second fixing sleeves. Characterized by being stationary at any axial distance The moving means cooperates with the stationary ring compressor to move the stationary ring compressor toward the stationary ring stop, whereby the stationary ring is placed between their relaxed position and the stationary position in the annular space between the stationary sleeve and the compression element. The axial compression in the axial direction to secure and secure the fixed sleeve by the head drum system is characterized in that it is mounted on the drive spindle. This embodiment is the same head disk fixing device as is known in the art, wherein the moving means passes through three equally spaced through openings in the head drum and is provided with three tension members for transferring a tension force between the two fixing ring compressors. Screw means for pulling the two stationary ring compressors towards each other by tensioning members extending through the openings.

In another embodiment of the present invention which uses two fasteners on both sides of the head drum, the head drum system is provided with at least one first and second conical hole on its first side and second side. Each hole has an inner wall whose bottom portion defines a cone portion with the first and second sides of the head drum apparatus respectively, wherein the first and second elastically deformable functional wall portions are the central holes of the head drum apparatus and the first and second portions. Wherein the first and second wall deforming devices have first and second fixing plugs having outer walls cooperating with the inner wall of the conical hole, the moving means A connecting bolt having a screw, wherein the connecting bolt extends through an opening from the first side to the second side of the head drum device, one of the two plugs being connected to the bolt Forming a head portion and the other fixing plug is characterized in that it forms a nut that is matched to the connecting bolt.

In yet another embodiment of the present invention, the first and second deformable wall portions are provided with first and second elastically deformable fixed slabs which are concentric with the drive spindle and have free ends and circumferential surfaces. The first and second wall deforming devices each have a first and a second fixing ring that deforms between a relaxed position and a fixed position. Characterized in that a fixed pressure is applied evenly on the circumference of the stationary sleeve, and each stationary ring has an axis and an angular surface with a right angle between the axis and the mother plane. Characterized in that it has an inner wall with a surface forming part, and through the axial movement in the opposite direction caused by cooperating with the outer circumferential surface of the fixing sleeve, the fixing ring moves from the relaxed position to the The fixed angle is smaller than the friction angle of the material used for the fixed sleeve and the fixed ring, and the friction force generated between the fixed sleeve and the fixed ring is applied to the fixed ring where the fixed force of the axial component is in the fixed position. It is characterized by preventing the return.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 illustrates a conventional spiral scanning video recorder suitable for magnetically recording and reading video signals of blocked signal tracks extending obliquely adjacent to each other on a magnetic tape. The cassette holder 2 is journalized to be pivotable in the housing 1 of the video cassette recorder. The magnetic tape cassette 3 can be inserted into the cassette holder in the direction of the arrow 4. When the cassette is fully inserted, the cassette holder can be closed and the cassette is placed in the operating position. At this position, the magnetic tape is taken out of the cassette by means provided in the video cassette recorder. This ultimately brings the magnetic tape into contact with the magnetic head. It is provided in an ordinary controller housing 1, for example a number of control buttons 5.

2 is an enlarged view of a part of the video cassette recorder of FIG. 1, and the cassette holder 12 is removed so that at least part of the inside thereof is visible. The video cassette recorder shown in FIG. 1 and FIG. 2 has at least partially free end 8 and is provided with cylindrical drive spindles 7 rotating around the rotation axis 6. The direction of rotation of the drive spindle is indicated by arrow 9 in FIG. The magnetic head 10 rotates in an annular line around the rotation shaft 6. The magnetic head signal tracks are recorded and read on magnetic tape. FIG. 2 shows only one magnetic head 10 and FIG. 3 shows the magnetic head of FIG. The magnetic tape itself and the slope signal tracks written on the magnetic tape are not important to the precise understanding of the present invention and are generally known about them. The free end 8 of the drive spindle 7 has a head drum system 13 having a first side 11 adjacent the free end 8 and a second side 12 away from the free end of the drive spindles. ) Is installed. This head drum system has two magnetic heads 10 and a central hole 14 is formed for mounting the head drum system to the drive spindle 7. A first center setting device 15 having a first elastically deformable wall 16 is located on the first side 11 to center the head drum system on the drive spindle. At a constant distance in the axial direction from the first center setting device 15, the center setting device 17 is located near the second side 12 of the head drum system 13. The second centering device has a second elastically deformable wall part I8 which cooperates with the drive spindle in the same manner as the first wall part 16 of the first centering device.

The first center setting device 15 on the first side 11 of the head drum system 13 acts as a detachable fixing device having a centering action, and therefore for the head drum system 13 on the drive spindle 7. Fixtures and centering devices are considered two types. The fixing device 15 (ie, the first center setting device) is matched to the first elastic deformable wall portion 16 and the second first elastic deformable wall portion 16 to apply pressure on the first elastic deformable wall portion. It consists of a wall deforming device 19. As a result, the wall portion is elastically deformed and fixed and centered on the drive spindle 7. The second elastically deformable wall portion 18 on the second side 12 of the head drum system is formed by a centering plate (see FIGS. 8 and 9), which is a thin sheet elastic material having a central opening 20. The drive spindles 7 fit completely within the opening 20 having the same shape and dimensions, and when the head drum system 13 is mounted on the drive spindle 7, a centering diaphragm adjacent to the center opening 20. The portion of 18 is subjected to elastic deformation in the axial direction by the force obtained between the centering diaphragm and the drive spindle. The centering diaphragm 18 is fixed by means of fastening means, which preferably comprises a compression member or thrust ring 21 (see FIGS. 10 and 11) and an opening 23 in the centering plate 18. ) And through the opening (24) in the thrust ring (21), it consists of a mutant (22) of the world clamped in the head drum (32). The thrust ring has a center hole 25 through which the drive spindle 7 penetrates with a slight gap. The thrust ring 21 as a fixing means does not affect a certain distance from the center opening 20 in the centering diaphragm 18. Thus, the parts of the centering plate located between the position where the fastening means mate the centering plate and the center opening are freely and elastically deformed for a limited distance.

The first elastically deformable wall portion 16 has an elastically deformable sleeve having a free end 26 and a stepped circumferential surface 27 concentric with the drive spindles 7. The wall deforming device 19, which exerts pressure on the stepped circumferential surface 27, is a fixed ring that is deformed radially between the relaxed and fixed positions, which ring is continuous, structured in a circumferential direction, and symmetrically radiated. The fixed pressure according to the deformation is applied to the fixed sleeve 16. The pressure acts uniformly over the circumference.

The wall deforming device 19 which acts as a fixing ring has a virtual, conical surface and a conical inner wall 28 whose shaft is in the form of a cone formed by the rotational axis 6 of the drive spindle 7. . The cone angle α of this cone represents the cone surface 29 of the cone shown in FIG. 3 and the auxiliary line 30 parallel to the axis of rotation 6. At the axial displacement of the fixing sleeve 16, the fixing ring 19 cooperates with the shoulder 31 on the fixing sleeve stepped circumferential surface 27, thereby becoming fixed in a relaxed state. Since the angle α is smaller than the friction angle ψ of the material used for the fixed sleeve 16 and the fixed ring 19, the frictional force generated between the fixed sleeve and the fixed ring is applied to the fixed ring in the fixed state. It is prevented from moving in the axial direction by the fixing force of the axial component. It is important that the clearance between the drive spindle 7 and the fixed sleeve 16 be about 15 microns or less when the retaining ring is in its open position to attain a satisfactory fixation pressure and at the same time achieve a sufficiently accurate centering. If the diameter of the drive spins is 6 mm, for example, a match designed for h5 / H6 may be used for matching in I, S and O systems. According to standard matching, the maximum tolerance of the drive spindle can be 5 microns, and the maximum tolerance of the center hole of the head disk can be 8 microns. For example, when the aluminum head drum 32 is used together with the brass fixing ring 19, the angle α may be 1 ° 30 '. By providing a shoulder 31 that cooperates with the conical inner wall 20 of the retaining ring 19 in the stepped circumferential surface, it is possible to deform the retaining sleeve 16 to a precisely defined position.

Mounting and dismounting of the fixing ring 19 to the fixing sleeve 16 can be performed by a simple hand tool. 5 and 6 show a tool for mounting the retaining ring. The head drum 32 is provided with a joint ring 33 for receiving the reaction force exerted on the head drum system by these tools coaxial with the stationary sleeve 16. 5 shows a sleeve 34 having two pins fixed to two sides facing in the radial direction. Here, the screw bolt 36 is tightened or loosened in the axial direction through the sleeve bottom center. The underside of the sleeve is provided with a flange 37 with a U-shaped groove 38. The size of this groove is such that the sleeve 34 can slide around the joint ring 33 of the head disk, and the flange 37 is fitted to the outer groove 39 at the lower side of the joint ring. Before the sleeve 34 slides onto the head drum, the retaining ring 19 is mated onto the stationary sleeve 16 and the thrust member 40 (see FIG. 6) is placed on the stationary ring 19. This thrust member has three projections 41 extending in the axial direction which rest on the upper surface of the fixing ring 19 around the fixing sleeve 16. The upper surface 42 of the thrust member 40 is formed with a conical hole 43 for receiving the conical end 44 of the thrust bolt 36. The retaining ring 19 is in a fixed position by tightening the screw bolt 36, and the conical end 44 of the screw bolt is inserted into the conical hole 43 to press the thrust member 40. The two pins 35 on the sleeve 34 are held by hand to prevent the sleeve from rotating in conjunction with the tightening of the screw bolts 36. The axial reaction force of the auxiliary tool is transmitted to the joint 33 of the head drum 32 by the flange 37. The auxiliary tool of FIG. 7 can be used to remove the retaining ring. The tool has a threaded bolt 45 with a conical end 46, a ring 47 with a flange 48, three pivotable extraction members 49 and an elastic wiring 50. Doing.

The lead member 49 has a lead protrusion 51 having a footrest 52. The lead-out protrusion 51 is connected to the upper part 53, which is connected to the upper part, which has an outer surface which forms part of the cylinder and also forms the groove 54 for the wiring 50. have. The upper portion 53 of each lead member 49 axially rests on the flange 48 and is elastically acted by the wiring 50 against the outside of the ring 47. The withdrawal member 49 is mounted on the ring 47 so that the withdrawal protrusion 51 is slightly turned outward, that is, at least until the footrest 52 is fitted with the fixed lip 19. The conical end 46 of the screw bolt 45 fits into the conical groove 55 in the free end 8 of the drive spindles 7.

When the screw bolt 45 is tightened, the foot plate 52 moves upward until it engages with the lower side of the fixing ring 19. The retaining ring is removed by tightening the screw bolt. The axial reaction force of this tool is transmitted directly to the drive spindles 7.

The centering diaphragm 18 of FIGS. 8 and 9 has a thickness of 0.1 mm and is made of chromium nickel (18Cr-8Ni) spring steel. The outer diameter of the centering diaphragm is about 20 mm and the three countries 23 passing through the bolt 22 are located on a pitch circle of about 16 mm. The opening 23 corresponds to the opening 24 of the thrust ring 21. The diameter of the center opening 20 of the centering diaphragm 18 is about 6 mm, and the inner diameter of the annular thrust surface 56 of the thrust ring 21 is about 12 mm. Thus, the distance between the edge of the center opening 20 of the centering plate 18 and the thrust surface 56 of the thrust ring 21 is about 3 mm. The degree of deformation of a portion of the centering diaphragm between the central opening 20 and the thrust surface 56 is shown in FIG. 3. In fact, the axial deflection is no greater than about 0.2 mm. When the centering diaphragms of FIGS. 8 and 9 are used, that is, when the diaphragms form the center opening 20 and have a thickness of about 0.1 mm, it is necessary to fit the head drum device 13 onto the drive spindle. The force is about 1000g. It can be seen that the head drum device can be sufficiently separated with a small force. This is due to the fact that the deformation in which the centering diaphragm buckles when the device is detached requires less force than the deformation when the head drum device is mounted.

The head drum device in FIG. 12 includes a first fixing device 61 on the first side of (60). This fixing device performs a detachable fixing operation to center the head drum device 60 on a drive spindle (not shown), and thus the first fixing device functions as a first center setting device. The first fixing device 61 has a first elastically deformable wall portion 62 which cooperates with the drive spindle. On this deformable wall portion is exerted a pressure by a wall deforming device, which will be explained in detail later. For this reason, the wall portion is elastically deformed and is thus centered and fixed on the drive spindle. The second fixing device 63 is supplied to the other side of the head drum device 60, which has a separable fixing action to center the head drum device on the drive spindle. It also acts as a second centering device. The second fixing device 63 has an elastically deformable second wall portion 64 and a wall deforming device, which will be described in detail later, which pressurizes the wall portion 64 to deform the second wall portion, elastically. The tongue drum device is thus centered and fixed on the drive spindle.

Three cooperating members of the wall changing device of the second fixing device 63 are formed in the head drum 65 constituting a part of the head drum device from the first side of the head rumbling device 60. Penetrate through) In Fig. 12, only one ball is shown. The elastically deformable first wall portion 62 and the second wall portion 64 have cylindrical fixing sleeves with free ends 66, 67, which free ends are concentric with the circumferential portion of the drive spindle. Is fitted. The first and second wall edgers are provided with a first retaining ring 68 and a second retaining ring 69, respectively, which are concentrically fitted to the retaining sleeves 62, 64 and are axially oriented. Under the influence of the force, it deforms radially at the relaxed and fixed positions. The first compression bushing 70 and the second compression bushing 71 are arranged concentrically around the fixed sleeves 62, 64, leaving annular spaces for the fixed rings 68 and 69, respectively. Also provided are first and second fixed ring compressors 72, 73 that are axially movable in cooperation with the first and second fixed rings 68, 69 to axially compress the rings. In the illustrated embodiment, the compressor has inwardly facing flanges on compression bushes 70 and 71, respectively. Generally, separate members can be used for this. The head drum 65 has a shoulder 74 at a predetermined distance in the axial direction from the free end 66 of the first fixed sleeve 62. This shoulder forms a stop for the retaining ring 68. The other shoulder is provided with a stop 75 for the fixing ring 69. The stationary ring compressors 72 and 73 operate together with the moving means for moving the stationary ring compression member in the direction toward the stationary ring stops 74 and 75. As a result, the fixing rings 68 and 69 move into the annular space between the fixing sleeves 62 and 64 between the relaxed position and the fixed position and are thus elastically deformed in the radial direction. In this way, the fixed sleeves 62, 64 and the head drum device 60 are fixed and centered on the drive spindles.

As described above, the head drum 65 has three through openings 86. They are located at the same distance and at the same angle from the rotational axis of the head drum device 60. As shown in FIGS. 6 and 7, the moving means for moving the fixed ring compressors 72 and 73 in the direction of each other is provided with three drawing members 77 penetrating through the through opening 86. do. These members transfer tension between two stationary ring compressors. In addition, the moving means is provided with a screw means for withdrawing the two fixed ring compressors 72, 73 in the direction of each other by the withdrawal member 77 penetrating the through opening 86. These screw means are provided with a screw bush 78 integrated with the drawing member and a screw plug 79 cooperating with the screw bush. The lead member 77 has a screw groove 80 for the bolt 81 and the screw plug 79 has a plurality of slots 82 for a tool (not shown). The bolt 81 (three bolts are already provided) extends through the opening 83 in the flange 84 formed on the compression bush 71. It has a compression bush 79 and a small flange 85.

This assembly is mounted as shown in FIG. The central hole 86 of the head drum device 60 has a diameter slightly larger than the diameter of the drive spindles to which the head drum device is attached. In order to fit these two diameters together, the same method as described above with respect to the embodiment of FIG. 3 must be applied. After positioning the head drum device 60 on the drive spindle, the screw plug 79 is rotated by a suitable tool and at any moment the lower side of the screw plug comes into contact with the flange 85 of the compression bushing 70. . When the threaded bush 79 is rotated more, the compression bushing 71 is moved even more through the withdrawal member 77, and at any moment, the stationary ring pressure gauge 73 comes into contact with the stationary ring 69. Both of the stationary ring compressors 72, 73 are in contact with the stationary rings 66 and 69, respectively. By rotating the threaded bush 79, the stationary ring compressors 72, 73 are tensioned in each other direction so that the stationary rings 68, 69 are axially compressed into the closed annular space in which they are located, Thus, it extends radially to exert pressure on the fixed sleeves 62, 64. As a result, the fixing sleeve causes a uniformly distributed deformation on the circumference and thus fixes the head drum device 60 on the drive spindles of the first side and the second side. When the threaded plug 79 relaxes, the retaining rings 68, 69 return from their fixed position to their relaxed position by their own elastic forces. At this time, it is preferable that the fixed ring extending in the axial direction has a minimum resistance as a result of the friction generated between the inner wall and the outer wall of the fixing sleeve. It is therefore preferred that the retaining ring is made from a magnetically active material such as polytitra fluoroethylene. The head drum device 90 shown in FIG. 18 has a head drum 91 mounted on drive spindles 92 that rotate about a rotation axis 93. On the first side 97 of the head drum, a conical hole 94 is formed at a constant distance from the central hole 95 of the head drum 91. The conical hole has an inner wall in which the base of the hole forms a conical portion facing the first and second sides of the head support, respectively. The elastically deformable first and second wall portions 91 and 100 are located between the central hole 95 of the head drum apparatus and the first and second conical holes 94 and 96, respectively. The first and second wall deforming devices are provided with first and second fixing plugs 101 and 102, respectively. These plugs have an outer wall which cooperates with the walls of the conical holes 94 and 96. In addition, an isolating means cooperating with the first fixing plug 101 to move the plug in the direction of the second side part 98 of the head drum device, and the plug in the direction of the first side part 97 of the head drum device. And a means for cooperating with the second fixing plug 96 for movement. In the head drum 91, a through opening 103 extending from the first side 97 of the head drum to the second side is formed. These openings receive the means of movement in the form of connecting bolts 104. The first fixing plug 101 forms the head of the connecting bolt, the second fixing plug 102 is formed by a nut coupled to the connecting bolt. The fixing plug 101 is formed with a hole 105 of a hexagonal cross section in which an open end spanner can be positioned to tighten the connecting bolt 103. The fixing plugs 102 and 101 are tensioned with each other while the connecting bolts are tightened to apply pressure to the elastic wall portions 99 and 100. As a result, the elastic wall portion is elastically deformed and the head drum device is centered and at the same time, the drive spin is fixed to the image 92. Obviously, the wall shaping device can be used in the form of a fixed plug regularly spaced around the drive spindle 92.

Fixing sleeves 114 and 115 that elastically deform are the first side 111 of the head drum 113. The head drum device 110 of FIG. 19 is almost similar to the head drum device 13 of FIG. 3 except that both sides of the second side are provided. In addition, two fixing rings 116 and 117 are provided, which move between the open position and the fixed position over the conical outer surfaces of the fixed sleeves 114 and 115. In order to be able to move from the first side 111 of the second fixing ring 117 on the second side 112 of the head drum 113, a few, for example, three openings are formed in the head drum. By means of the auxiliary tool (which is in principle little different from the tools shown in FIGS. 5 to 7), the fixing ring 117 is connected to their release and fixing positions via the fixing ring 116 and the opening 118. You can move between them.

Claims (1)

Cylindrical drive spindles 86 and 92 having free ends and revolving shafts 76 and 93 and a stop guide drum concentric with the axis of rotation and guiding the magnetic tape and cylindrical portions of the drive spindles 86 and 92 near the free end. The drive spindles are configured to be secured, the first side being spaced apart from the stationary guide drum and the second side spaced by a narrow gap from the stationary guide drum, and at least one protruding magnetic head and head drum system near the gap. It is fixedly connected to the rotating head drum system 60, 90, 110, which includes a center hole 14, etc. for mounting onto the top 7 and the first side of the head drum system, and cooperates with the drive spindle by direct contact. A first elastically deformable wall portion (62, 99, 114) on the first side of the head drum system (60, 90, 110) centering the head drum system on the drive spindles (86, 92). First center setting device In a tape recording and reproducing apparatus, a second elastically deformable wall portion (64, 100 or 115) elastically cooperating in direct contact with a cylindrical portion of a drive spindle and fixedly connected to a second side of a head drum system. And a second centering device on the second side of the head drum system for centering the head drum system on the drive spindle and at least one opening extending from the first side to the second side of the head drum system. 103, 118, means 69, 102 or 117 configured to deform the second wall 64, 100 or 15 of the second centering device to elastically match the cylindrical part of the drive spindle. Magnetic recording and reading device for the signal.