KR820001293B1 - Arrangement for centering aligning and retaining a rotating record - Google Patents

Abstract

The device is intended for an optically scannable record dive with a center aperture. It has a drive spindle(14) with a free end. With the wall of the plate center aperture cooperates a centering device(17) near the spindle free end. The spindle also carries a disc aligning device(18), effective in a plane orthogonal to the spindle axis of rotation. With the drive spindle is firmly coupled a dive guide (18). The centering device has centering members(29), movable between a rest position & an operating position, further away from the spindle axis of rotation. Their rest position is spring-loaded. On insertion of the record dive, the centering members tend to overcome the spring force.

Description

Centering, Alignment and Retention of Rotating Records

1 is a perspective view of a video disc player for centering, aligning and retaining a video disc with an opening cover.

2 is an enlarged view of a main part of FIG.

3 is a partial cross-sectional view of the drive spins of the video disk of FIG. 1 when the lid is closed.

4 is a cross-sectional view of the central registration device integrally made of synthetic resin used in the embodiment of FIGS.

5A, 5B, and 5C are enlarged views showing the main parts of FIG. 3, respectively showing states in which the video disc is arranged at different positions with respect to the center-matching member.

6 is a spring characteristic diagram of the central matching device of FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for centering and aligning a rotating rigid disc-shaped record carrier with a central disk hole in an operating position, and more particularly, to a center-matching and alignment and retention device of an optically readable video desk. The device comprises a drive spindle that has a free end and can be rotated relative to the rotational side, and a central matching device disposed near the free end of the drive spindles and cooperating with the wall of the central disc hole at the operating position of the disc; A disc aligner having one or more support surfaces for the disc attached to the drive spindles for aligning the disc to an in-plane actuator perpendicular to the axis of rotation of the drive spindles, and in a position opposite to the centering device Can be moved and restrains the disk to an operating position to narrow the support surface of the disk aligner. To and a portion for holding the disc to its operative position.

Such a video disc player device is described in the specification of Dutch Patent Application No. 7609375 by the applicant. The player's centering device has a centering member in the form of a centering cone with a cone attached firmly to the drive spindles. In addition, the disk aligner is provided with a flange that rotates in line with the drive spindles, but can be axially moved with respect to the centered conical body and is slidably guided on the drive spindles.

When disposing the video disk by the action of this coalescing cone, it is centered about the axis of rotation of the drive spindles.

The weight of the video disk causes the disk aligner to drop against some elastic action and the disk hole wall of the video disk contacts the surface of the centering cone. This disc aligner accurately aligns the video disc at right angles to the axis of rotation of the drive spindles, but does not prevent the wall of this disc hole from engaging the surface of the centered cone.

The disk load is magnetically driven in the direction of the cone to press the disk hole wall against the surface of the centered cone with this driving force, but in this case the force is sufficient to start the video disk and rotate or brake it during operation. It is the force that produces the friction torque of size. This disc aligner also imparts some friction to the video disc as a result of the elastic action. An unbalanced force due to the incomplete distribution of mass in the video disc does not affect the accuracy of the central match. This is because the wall of the disc hole keeps in contact with the centering cone during operation. Since the disk hole is relatively large and the centered conical body has a shorter dimension that varies from a smaller size to a larger dimension than the disk hole, the mounting operation of the video disk is simple.

The drawbacks of these and similar center-matches and alignment and retention devices are that the diameters of the disc holes actually vary from disc to disc, so that the side position of the disc on the disc cannot be determined in advance. The change in diameter caused by making this centered conical body relatively thin causes a change in the axial position of the disk on the pins during driving, which is almost four times larger. In the case of a video disc player having a disc of about 35 mm in diameter with a disc hole of 30 cm in outer diameter, the change in the axial direction of the disc on the drive spindle can be about 700 microns as a whole. This disc hole diameter change can be caused by manufacturing tolerances and the influence of ambient temperature and humidity.

In an optical video disc player, it is important to accurately position the disc at a predetermined axial position on the drive spindle for two reasons described below.

The first reason is that the read objective should not touch the disc. During operation, the objective is placed at a distance of 1.5 mm from the surface of the rotating disk to focus the read beam. However, even if the servo control system of this objective lens is defective, it is necessary to prevent this expensive component from being damaged. For this purpose, stop means are provided for limiting the distance that the objective lens can move in the disc direction. As will be apparent from this, the amount of deviation that the disk surface is allowed in the axial direction is almost a slight amount. Video discs are not completely flat and their weight causes warping, especially in the vicinity of the periphery.

Because of these effects, it is suitable for the axial position of the disk surface to cause a shift as described above, and to avoid other adverse influences due to the deviation of the diameter of the disk hole.

The second reason is that it is important to properly regulate the axial position on the drive spindle in order to obtain the stability of the disc. A stationary stabilizing disc can be provided above the rotating surface of the disc. If the distance between the rotating disk and the stabilizing disk is small, an aerodynamic effect can be created, which can be used to stabilize the disk, but this effect is highly dependent on the distance between the two disks. If the distance between the disc-shaped record and the stabilizing disc is too far to stabilize this disc, the opportunity for the objective lens to contact the disc-shaped record becomes greater.

Another drawback of this known device is that it is necessary to guide the disk aligner on these drive spindles in order to be able to move the disk aligner in the axial direction.

Because of the flow required for guiding the disc alignment slot, a separate alignment error may occur at the disc position. During operation, the video disc rotates at a speed of 25 or 30 Hz, depending on the method used to encode the information to the disc, so this alignment error results in correct positional accuracy, which is 25 or 30 in the optical projection of the disc information. It occurs repeatedly at the rate of Hz. Since it is necessary to focus the light beams used during the reading period using bi-optical means with a precision of less than 1 μm, a servo system for focusing the light beams is provided as described above. Therefore, this alignment error causes a new error for servoing the light. Moreover, this misalignment also affects the inaccuracy of the center of the disc. For reading by this optical means, it is suitable to install a tracking servo system to center the information track with accuracy better than 50 microns. In this case, the alignment error results in a central agreement error of 15 microns.

It is an object of the present invention to provide an apparatus of the type described at the beginning of the present specification which ensures excellent positioning and alignment in the axial direction of the disc while at the same time accurately centering the disc even in the case of local irregularities in the wall of the disc hole. It is.

In the present invention, the disk alignment mechanism is firmly coupled to the drive spindles, the center matching disk has a plurality of center matching members, and these center matching members have a radius between the resting position and the operating position on the side close to the rotation axis. Directionally movable, furthermore having elastic means for directing the centering member to their rest position, which centering member cooperates with the wall of the disk hole when mounting the disk to the drive spindle. It is characterized in that a movement against the action of the means can be obtained.

In order to achieve this object by the present invention, the disk arranging member can be firmly coupled to the drive spindles so that, for example, a fixed flange can be installed on the disk arranging member, but the center of the disk is provided by a centering member which can move in a radial direction. Matching can be done correctly. It is also suitable to use multiple movable centering members. In this case, the local irregularity of the wall of the disk hole can suppress the influence on the center of the disk to a minimum, but in this case, in order to reliably and accurately center the disk, there is a relatively small elasticity in each centering member. Therefore, plastic deformation of the wall of the disk hole is prevented.

In a particularly suitable embodiment of the present invention, these elastic means are provided with rod springs, and these rod springs are integral with the central mating member so that they can be accommodated adjacent to each other in a limited space available. The spring is coupled to the drive spindle by a fixed end.

In another embodiment of the present invention to facilitate mounting of the disk to the drive spindles, the rod springs have a kink shape at least on the side away from the axis of rotation of the drive spindles so that these rod springs are free of the drive spindles. By constructing a stop cone in the rest position on the side disposed near the end, the cone has a transverse dimension that changes from a smaller than the diameter of the disc bore to a larger one, and furthermore the rod spring has the drive spindles. On the side distant from the free end of the cylinder, a cylindrical portion is formed in the working position, which has the same transverse dimension as the diameter of the disk hole. In the final position on the drive spindles, the disc is arranged in the cylindrical part of the centering disc, so that no axial force directed to the free end of the drive spindles acts on this disc. For this reason, there is no fear that this disk will be removed from the drive spindle by the action of the elastic force.

An imbalance in the video disc results in centrifugal forces acting on the drive spindles during operation, but this does not displace the disc radially and axially.

This centrifugal force is absorbed by the centering member and by the frictional force created by the clamping force between the disc load port and the disc and between the disc and the disc alignment section. The support surface of the disk alignment tool can be made of a material having a large coefficient of friction.

In another embodiment of the present invention, the elastic means for the centrally matched member has a certain spring constant (which is given by an index between the change in elastic force and the change in elastic displacement), whereby the spring constant is at rest. When shifting from a position to an operating position, it can be changed from a small value to a large value. In this embodiment, the positioning of the video disk can be performed relatively easily since the spring constant is small initially, but during operation, the spring constant becomes large, so that the alignment of the video disk becomes accurate and the centrifugal force is absorbed.

In the device for engaging the center-matching member by the rod spring, each rod spring has a free end, and furthermore, the driving spindle has a stop means for cooperating with the free end of each rod spring between the rest position and the construction position. It can be installed in a place so that the spring constant can be changed step by step. By the presence of this stop means, the kink portion spring characteristic is obtained. This property is also suitable for the embodiment of the present invention described above, in which a portion of the center engagement disk is in the form of a stop cone, so that the bottom of the double engagement device is in the form of a stop cylinder during operation.

In this case, the transition from one part of the spring characteristic to the other part may occur when the point of shifting between the cone and the cylindrical part of the centering device between the mounting of the video disc is reached.

Since the component of the axial force does not act on the video disk in the vicinity of the cylindrical portion, there is little problem even if the elastic means has a locally high rigidity during mounting of the video disk.

From a manufacturing point of view, in another embodiment of the present invention, the centering device is attached to the drive spindle in one unit. In this case, the unit can be provided with the rod springs and these rod springs, and at the same time, with these integral retaining rings. Suitably, the center coincidence device is integrally manufactured by a plastic injection molding process.

In the case of using a rod spring cooperating with the stop means to obtain the kink portion spring characteristic, in view of optimally centering the disc, this stop means has a wall portion of the coaxial cylindrical stop member which is firmly attached to the drive spindle. You can do it. As a result, an optimum center coincidence accuracy can be ensured.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

In the drawings, corresponding components are denoted by the same reference numerals. The video disc player 1 shown in FIG. 1 has a housing 2 and a cover 3 hinged thereto. On the front of this housing, a plurality of operation buttons 4 and 5 are arranged for performing various functions. In the central place, there is a device 6 for centering, aligning and retaining the video disk 7. This disk has a disk hole 8. You can place this disk on this device. This allows the disc to be configured at a predetermined rotational speed of 1,500 or 1,800 revolutions per minute, depending on the frequency of 50 or 60 Hz. The upper surface of the housing 2 is formed with a slot 9 adjacent to the apparatus 6 and extending in the radial direction. In this slot, the focusing apparatus 10 is able to move in the radial direction, and this movement is accommodated in the housing and is carried out using any unillustrated means. This focusing apparatus is equipped with the objective lens 11, and can focus the light beam from the laser source which is not shown by this objective lens to the lower surface of the disk arrange | positioned on the apparatus 6. As shown in FIG. Moreover, the objective light can be used to pass the reflected light from the disk to the photoelectric information detecting means provided inside the housing 2. As shown in FIG.

The drive motor 12 shown in FIG. 3 has drive spindles 14, which can rotate around the axis 13 of rotation. The free end 15 of this spindle is slightly cut off. In the vicinity of this free end 15 the centering device cooperates with the wall 16 of the disc hole 8 in the center of the video disc 7 when the disc is in the operating position. Furthermore, a flange alignment mechanism 18 in the form of a flange is attached to the drive spindles 14 so as to align the disc in the inner working position perpendicular to the rotation axis 13 of the drive spindles 14. The disc alignment tool 18 has a support surface in the form of a hard rubber ring 20 for supporting a video disc, which ring is arranged in an annular groove 19. The cover 3 carries the disk load port 21. The load port can move to a position opposite to the centering device 17, and at the same time, presses the video disk 7 to the disk alignment port 18 in the operating position. The load in the direction of the ring 20 is given, thereby holding the disk. With the aid of the holes 22, the load port 21 of the disk has flow and engages the drive spindles 14 and cooperates with the disc-shaped permanent magnet 23 attached to the drive spindles. Cover 3 has room 24, which contains the flanged portion 25 of the disk load port with flow. On the other hand, the cylindrical portion 26 of the disc load port protrudes through the opening 27 of this chamber 24. Thus, when the cover 3 is closed, the disk load port can freely rotate with the drive spindles 14. When the cover is opened, the disk load port is drawn out of the drive spindles by the action of flange 25.

The permanent magnet 23 and the flange 18 are coupled to the member 28 so that the member fits into the drive spindles 14 and is thus firmly coupled to the drive spindles. The centering mechanism 17 has a centering member 29, which can move radially between an operating position (see also FIG. 5C) and a rest position (see also FIG. 5A) located in the vicinity of the rotation axis 13. . These centered mating members are in the form of rod springs, and furthermore, as is apparent from FIG. 4, the member may be manufactured by the extrusion molding of the synthetic resin together with the retaining ring 30 to constitute a single component. As a suitable material, for example, 1% of silicone oil is added to polycarbonate to reduce the coefficient of friction. When the video disk is fitted to the drive spindles, these centering members can cooperate with the wall 18 of the disk hole 8 of the disk 7 to obtain a movement opposite to the elastic action.

These rod springs 29 have a kink shape on at least an axis away from the axis of rotation 13 of the drive spindles 14, so that in the resting position these rod springs together form part of the shaft near the free end of the drive spindles. The size of the transverse direction of the truncated cone is changed from the smaller than the diameter of the disk hole 8 of the video disc 7 to the larger one. Furthermore, in the operating position, the rod springs are formed at the side away from the free end 15 thereof. By constructing the stopper cylinder, in that case, the dimensions in the transverse direction of the binary cylinder are equal to the diameter of the disc hole. A description with reference to FIGS. 5A to 5C is as follows.

The spring constant of these centering members 29 changes from a small value to a large value while moving the centering means from the rest position to the operating position.

5A to 5C show the moving direction in which the centering member 29 moves from its rest position to its operating position when the video disc 7 is mounted. Each centering member has a fixed end 31 coupled to the retaining ring 30 and a free end 32 on the opposite side thereof. This free end engages the stop means, which have the form of a hook and form part of the member 28 which is fitted and engaged on the spindle 14.

FIG. 5A shows a state in which the wall 16 of the disc hole 8 of the video disc 7 is in contact with the portion 34 of the center mating member 29 when the video disc is moved downward in the direction of the arrow D. FIG. This part 34 together forms the interruption cone described above. While moving the video disk in the direction of arrow D and further downwards, the centering member 29 is moved in the direction of the rotation axis 13 of the drive spindles so that the stop end 35 stops 33 as shown in FIG. A position is reached to make contact with. This movement is carried out under the cooperation of the wall 16 of the disc hole and the above-mentioned center coalescing member. The double match tooth member 29 pivots around the fixed end 31 between the two positions shown in Figs. 5A and 5B. However, once the position of FIG. 5B is reached, the double engagement member can no longer be turned by the cooperative action of the stop portion 35 of the center engagement member 29 and the stop means 33.

6 is a diagram showing a state in which the turning force F in the direction of the rotation axis 13 acting on the center mating member 29 changes in the state shown in FIGS. 5A and 5B. Point A in this diagram corresponds to the state of Figure 5a, in which case the force F is apparently zero. Point B corresponds to the state shown in FIG. 5B, in this case after displacement of 75 microns and its force is 0.3 Newtons. This spring constant is a field defined by the quotient by dividing the force F (in Newtons) by the displacement d (in microns) and is equal to tan α over the entire path between two points A and B. When the disk 7 is further displaced in the D direction, the disk 7 finally arrives from the state shown in FIG. 5B to the state shown in FIG. 5C, and the disk 7 engages the ring 20 in the flange 18. In this case, in order to deform the centering member 20, a larger force is required in the direction of the rotation axis 13, and between two points B and C in the diagram shown in Fig. 6, the desired force F is 0.3 Newton during the displacement of 10 microns. To 2 Newtons. In this range, the spring constant is tan βdlek.

During the final displacement of this disc 7, the wall 16 of this disc hole 8 moves from part 34 of the centering member 29 to part 36. In the state shown in FIG. 5C, the surface 36 of the central mating member 29 together forms a stopper cylinder. The exact center registration of the disk on the center registration device is obtained by the cooperation of the wall 16 and the part 36 of the center registration member 29. The cylindrical surface of the interruption portion is provided on a concentric circle with respect to the rotation axis 13. The accuracy of this concentricity is also improved by the stop means 33 having a cylindrical shape. In other words, this stop means constitutes a cylindrical stop member for all of the centering members 29, which is firmly and coaxially attached to the drive spindles.

While the foregoing has described only one embodiment of the invention, many other embodiments based on the principles of the invention may be included. Therefore, within the scope of the present invention, for example, a separate center matching member such as a ball or pin shape capable of radially moving in the slot or hole can be used. In this case, for example, the radial movement of the balls or pins is done by pressing them outward in the radial direction using a suitable spring.

Claims (1)

In the operating position of the drive spindles 14 which can rotate around the rotating shaft 13 with the free end 15 and the disk 7 provided near the free end 15 of the drive spindles 14, The centering mechanism 17 cooperating with the wall 16 of the disc hole 8 and the drive spindles for aligning the disc 7 in an in-plane operating position perpendicular to the rotation axis 13 of the drive spindles 14. 14, a disc aligner 18 having at least one support surface 20 for the disc attached thereto, which can be moved to a position opposite to the centering mechanism 17 and suppresses the disc 7 With a support surface 20 of the alignment tool 18, a disk load port 21 for retaining the disk in its position, centering the disk 7 with the central disk hole 8 in the operating position , In the alignment and retaining device (6), the disk alignment mechanism (18) is rigidly coupled to the drive spindles (14) (17) is provided with a plurality of center matching member 29, these center matching member 29 is characterized in that it can be moved in the radial direction between the rest position and the operating position located near the rotation axis (13) Centering, aligning and holding devices for rotating records.

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