DISK PLAYBACK APPARATUS

Abstract: A recorded disk playback apparatus in accordance with the present invention includes a sub-chassis (126) whose one end is supported as turntable by the main chassis (124) that is housed in a main frame, a carriage (156) which is freely movable on the sub-chassis (126) to feed the pick-up head (154) in the radial direction of the recorded disk (14), a turn table (16) which is placed on the sub-chassis (126) to have the record disk placed on it, a slide table (122) which transports the record disk to the position which coincides with the center of rotation of the turn table (16), a disk clamper (24) which is fixed rotatably to the main chassis (124), an adjustable mechanism (164,178) which moves the carriage (156), as well as turns upward/downward the sub-chassis (126), a driving motor (166) which, by the driving of the adjusting mechanism, serves commonly for the feeding drive of the pick-up head (154) and the turning drive of the sub-chassis (126), and a locking/unlocking mechanism which locks/unlocks the slide table in association with the operation of the adjusting mechanism. The engagement/ disengagement of the disk clamper (24) with respect to the recorded disk which is placed on the turn table is controlled by the raising/lowering drive of the sub-chassis. The adjusting mechanism may comprise a rack which moves in the radial direction of the recorded disk under the power of the driving motor, a stopper which defines the range of operation of the carriage, a linking mechanism which makes the linkage possible between the rack and the carriage within the range of operation of the carriage, and a raising/lowering mechanism which raises-lowers the sub-­ chassis in association with the shifting operation of the rack.

Description: The present invention relates to a record playback apparatus for audio and video information. Several years ago, there was introduced in the fields of audio and video an optical video disk in which the information in the recording disk (referred to as the disk hereafter) is reproduced, by irradiating the disk with the laser light, as signals that are represented by the variations in the amount of returned light due to diffraction by the pits. As for the playback apparatus, the front loading system is in wide use in which loading/unloading of the disk is carried out from the front of the playback apparatus for the reasons of easy operationability and efficient utilization of the space. In what follows a description will be given about a prior art recorded disk playback apparatus for optical disks of the front loading type by referring to Figs. 1 through 9. In Fig. 2 is illustrated the state in which the slide table 10 for taking in and out the disk is pulled out of the main frame 12 of the playback apparatus, while in Fig. 1 is shown the state in which the slide table 10 is pushed in. The situations for the operation of loading/unloading are illustrated in Figs. 3 to 5. In Figs. 3 and 4 there is illustrated that the lifter 18 which acts to place the disk 14 onto the turn table 16 is installed on the slide table 10 in a manner that is freely movable up and down. On the turn table motor 20, the turn table 16 and the center spindle 22 for centering the disk 14 are installed so as to rotate with the turn table motor 20 as one united body. The disk clamper 24 which moves up and down due to the turning of the support arm 28 that turns around the fulcrum 26, plays the role of clamping the disk 14 onto the turn table 16. For loading the disk, the disk 14 is placed on the slide table 10 that is pulled out, as shown by Fig. 3, and then the slide table 10 is pushed in as shown by Fig. 4. It becomes now necessary to place the disk 14 on the turn table 16, since in this state the disk 14 is sitting still on the slide table 10. When the slide table 10 is pushed in, the lifter 18 that was supporting the disk 14 moves downward to a position which is lower than the turn table 16, leaving the disk 14 on the turn table 16. At the same time with this, the disk clamper 24 that is installed on the center stay 30 comes down to clamp the disk 14. By these actions, the disk 14 is clamped between the turn table 16 and the disk clamper 24, and the disk 14 rotates fast due to the rotation of the turn table motor 20. In Fig. 5 is illustrated the state in which the loading of the disk 14 is completed. For unloading the disk 14, it is needed to reverse the above actions. Namely, the disks 14 that was rotating as in Fig. 5 is brought to a stop, the disk clamper 24 and the lifter 18 move upward as shown by Fig. 4, the disk 14 is replaced from top of the turn table 16 to top of the lifter 18, and the slide table 10 is pulled out as shown by Fig. 3 to have the disk 14 to be taken out. The mechanisms for carrying out the loading/unloading as described in the above will be illustrated in Figs. 6 and 7. In Fig. 6 are shown the mechanism of the loading drive motor and the construction of the disk clamper. The rotation of the loaidng drive motor 32 is transmitted to the pinion 44 via the belt 34, a small pulley 36, and a large pulley 38, its speed being reduced by the worm 40 and the worm wheel 42. On the rack 46 there are created long openings 48a and 48b to which are inserted in slidable fashion the posts 52a and 52b, respectively, that are installed protruding from the bottom of the chassis 50. Since the pinion 44 and the rack 46 are kept engaged between them, the rack 46 is possible to move back and forth (in the directions of arrows in the figure) with respect to the main frame of the playback apparatus by the rotation that is transmitted to the pinion 44. On the other hand, the disk clamper 24 moves up and down with the turning of the two arms 28a and 28b, one each of whose ends are supported on both sides of the chassis 50 by the pins 26a and 26b, that move pins 26a and 26b as the fulcrums. On the arm 28a there is formed a sloped cam 54 which makes a direct contact with the roller 57 that is installed on the rack 46 to be freely rollable, by mens of a spring 56 whose one end is attached to the arm 28b. Here, a U-shaped metallic fitting 58 is installed as turnable on the indentations 58a and 58b that are prepared on both sides of the chassis 50, and the branches 60a and 60b on both ends of the U-shaped fitting make contact with the rollers 62a and 62b prepared on the arms 28a and 28b so as to have the force of the spring 56 apply equally on the two arms 28a and 28b, to help the ascent/descent of the disk clamper 24 to be carried out correctly horizontally. With the rotation of the motor 32 being transmitted to the pinion 44 by the above mechanism, as the rack 46 moves to the front of the main frame of the playback apparatus 12, the disk clamper 24 goes down, and as the rack 36 moves to the rear, the clamper 24 goes up. Next, Fig. 7 shows the construction of the slide table, the lifter, and the ascent/descent cams. At the four corners of the lifter 18 there are installed cylindrical protuberances 64, and corresponding to these protuberances 64 there are formed on both inner surfaces of the slide table the guiding grooves 66 for guiding the protuberances 64 in the up and down directions. The respective cam holes 72 in the left ascent/descent cam 68 and the right ascent/descent cam 70 engage the protuberances 64 of the lifter 18, holding the lifter 18 so as to be slidable in the longituadinal direction along the inner sides of the slide table 10. The hole 76 created at the central part of the connecting rod 74 engages with the pin 78 of the slide table 10, and the pins 80a and 80b at both ends of the connecting rod 74 engage with the left ascent/descent cam 68 and the right ascent/descent cam 70, respectively. On the left ascent/descent cam 68 there is prepared a post 86 for receiving the transmitted displacement motion of the rack 46 through its engagement with the protuberances 82 and 84 that are installed protrusively at the center of the rack 46. Figures 8 and 9 show views from bottom of the slide table 10. In such a mechanism, when the rack 46 in Fig. 6 is shifted back and forth with respect to the main frame 12 of the playback apparatus, the left ascent/descent cam 68 is moved as shown by Figs. 8 and 9, the displacement motion being also transmitted to the right ascent/descent cam 70 by means of the connecting rod 80. Then, it becomes possible to raise and lower the lifter 18 by maintaining the protuberances at the four corners of the lifter in simultaneous horizontal state by the help of the cam holes 72 of Fig. 7, accomplishing the loading/unloading of the disk mentioned earlier. However, in the prior art recorded disk playback apparatus as described in the foregoing, a motor for feeding drive of the playback pick-up head and a speed reduction mechanism (not shown) are required separately from the motor for loading drive 32 of the disk and the speed reduction mechanism, hindering the effort for reducing the size and weight of the apparatus. Moreover, in the prior art construction as described in the above, it is necessary to clamp the disk 14 by lowering the disk clamper 24 so that there is required a mechanism for lifting/lowering the disk clamper 24. Furthermore, it is also necessary to incorporate in the apparatus a mechanism for lifting and lowering the lifter 18, hindering the effort to reduce the size of the apparatus by the increase in the number of parts required. In addition, the slide table 10 and the lifter 18 are being given separate piece constructions. Because of this, in the slide table 10 there is created an opening for letting the lifter 18 to pass through in order to lift and lower the lifter 18 with respect to the slide table 10. However, since the slide table 10 is pulled out and pushed in frequently, it has to be made strong enough so as not to be broken easily, considering the case where an unintentional force in the up and down direction is applied to it. Therefore, it leads to a weakness that the apparatus has to be constructed by using a thick material in order to give the lifter 18 a separate piece construction and make it still strong enough not to break easily even with a large opening in it. Now, in Fig.10 there are shown the prior art construction of the slide table and its locking/unlocking mechanism. In Fig. 10, the slide table 10 is shown to be given a mechanism in which it is made slidable inside the main frame 50 of the chassis by means of the rollers and the rails (not shown). In order to load the disk on the playback apparatus, the slide table 10 is pulled out from the front of the playback apparatus, the disk is placed on it, and then it is pushed in. The slide table 10 is locked in this state, the disk is placed on the turn table and is then held down by the disk clamper, the turn table rotates, and the state in which playback is possible is reached when the rotation of the turn table attains a fixed speed of rotation. The locking plate 90 for locking the slide table 10 is supported by the pins 92a and 92b so as to be slidable in the directions represented by the arrows a and b. The locking plate 90 is energized in the direction of the arrow a by a spring 94. The unlock holding lever 96 is mounted turnably on the locking plate 90 by a pin 98. The unlock holding lever 96 is energized in the clockwise direction as seen from the top by a spring 98. The stopper 100 which is prepared on the main frame 50 of the chassis acts, via the unlocking lever 102, to hold the locking board 90 there as it is moved to the left. The solenoid 104 that is attached to the main frame 50 of the chassis acts as the source of the power for moving the locking board 90 in the direction of the arrow b. On the arm 106 there are provided arm tips 106a and 106b, and the tip 106a is engaged with the plunger 108 of the solenoid 104 by a pin 110. The other arm tip 106b makes a direct contact with the bent portion 90a of the locking plate 90. By this arrangement, when the solenoid executes its sucking action, the locking plate 90 is moved in the direction of the arrow b. As the operation of the prior art mechanism as described in the above, when the locking roller 112a of the two locking rollers 112a and 112b of the slide table 10 starts to press the unlock holding lever 96, the unlock holding lever 96 is released from the stopper 100, the locking plate 90 slides in the direction of the arrow a under the force of the spring 94, and the locking action is completed by holding down the locking rollers 112a and 112b. To pull out the slide table 10, by operating the unloading button or the like, the solenoid 104 conducts electricity momentarily, and sucks the plunger 108. By this action, the arm 106 rotates to move the locking plate 90 in the direction of the arrow b of (d), and the locking of the locking rollers 90a and 90b is released. However, in the locking/unlocking mechanism due to the prior art techniques, for releasing the lock of the slide table, a solenoid with large power has to be utilized. The use of such a solenoid means a rise in the cost, and it is undesirable from the viewpoint of reduction in size due to the space occupied by the solenoid, and also is disadvantageous from the viewpoint of reduction in weight due to the weight of the solenoid. EP-A-0 048 759 shows a mechanism for a disk record and playback apparatus in which the guide means is hinged and can be lowered to position the disk onto a fixed turntable. The disk is pressed onto the turntable by means of a moveable clamping member attached to the guide means. The clamping member is magnetically attracted to the turntable, with the disk in between the clamping member and the turntable. Accordingly, an object of the present invention, which is devised in view of the above circumstances, is to provide a recorded disk playback apparatus which is capable of reducing the size and weight of the apparatus by diminishing the number of motors and the speed reduction mechanisms, as well as of improving the productivity and reliability by simplifying the mechanism for loading operation. Another object of the present invention is to provide a recorded disk playback apparatus which is capable of doing away with a large opening in the slide table for letting a lifter to pass through, by eliminating the up and down motion of the lifter by the unification of the slide table and the lifter, and also is capable of reducing the thickness of the material to be used, as a result of the increased strength in the slide table due to the unification. Still another object of the present invention is to provide a recorded disk playback apparaus which includes, separately from the main chassis, a sub-chassis that incorporates a turn table, supports the sub-chassis at one of its ends by a combination of gears, cams, and others to arrange for the turn table to be inclinable, and is capable of clamping the disk between the turn table and a disk clamper which is fixed to the main chassis. Still another object of the present invention is to provide a recorded disk playback apparatus which is equipped with a locking/unlocking mechanism that is capable of carrying out unloading of the disk without the use of a solenoid for releasing the locking of the slide table. One feature of the present invention is that in a recorded disk playback apparatus of front loading type which places a recorded disk on the turn table by means of a slide table and clamps the disk between a disk clamper and the turn table, it includes a motor which is used commonly for loading drive, unloading drive, and pick-up head feeding drive, and long openings, and further, it includes a rack which is movable in the radial direction of the recording disk under the power of the motor, and protuberances that are movable in the long openings. The apparatus is equipped with a carriage which is interlocked with the rack within a predetermined range of movement, a stopper for defining the range of the movement of the carriage, an interlocking mechanism which, after the movement of the carriage is regulated by the stopper, allows the carriage alone to be movable by the motor mentioned above, and after the regulation on the movement of the carriage is released by the stopper, makes it possible to interlock the rack and the carriage, and a pick-up head placed on the carriage for reading and playback the signals. Another feature due to the present invention is to provide a recorded disk playback apparatus in which a disk receiving section (the lifter) is formed in a unified body with the slide table, without lifting/lowering the lifter, the turn table, motor, pick-up head, and carriage are installed on the sub-chassis, and the sub-chassis is supported by the pins at the rear of the main chassis as turnable in order to realize a mechanism in which the turn table mounted on the sub-chassis ascends/descends with respect to the main chassis by the turning of the sub-chassis. In addition, the apparatus includes a disk clamper which is mounted freely turnably on the center stay, without being lifted/lowered, and a loading mechanism of the disk which lifts the disk off the slide table by raising the turn table and clamps it between the turn table and the disk clamper. Still another feature due to the present invention is to realize a recorded disk playback apparatus in which an unlocking lever, instead of a solenoid, is used for releasing the locking to pull out the slide table, and the locking of the slide table is arranged to be released by moving the locking arm by the unlocking lever, just before the completion of the unloading operation of the disk. This makes it possible to do away with the solenod, which leads to advantages in reducing the cost, size, and weight of the apparatus. According to the invention, there is provided a disk playback apparatus for reproducing information memorized in a record disk by means of a pick-up head, comprising: a main chassis which is housed in a main frame of the recorded disk play apparatus; guide means for carrying said record disk and adapted to move into a predetermined position in the apparatus suitable for enabling reproducing operation; a carriage for feeding the pick-up head in the radial direction of the record disk; a turntable for supporting the record disk by clamping it between said turntable and a disk clamper; and a turntable motor for turning said turn table together with the record disk, said apparatus characterized by a sub-chassis, pivotably supported at one end by said main chassis carrying said carriage and said turntable and by driving means and an adjusting mechanism for moving said carriage and for moving said sub-chassis upward/downward, whereby, when said guide means is in said predetermined position, the record disk is clamped by moving said turntable upward by means of said sub-chassis against said disk clamper with the record disk therebetween wherein said disk clamper and the record disk are rotatably fixed with reference to said main chassis. These and other objects, features and advantages of the present invention will be apparent from the detailed description of the preferred embodiments with reference to the accompanying drawings. Figure 1 and Fig. 2 are the external perspective views of a recorded disk playback apparatus due to the present invention and prior art, Figs. 3 to 5 are the explanatory diagrams for illustrating the loading operation in the prior art recorded disk playback apparatus, Fig. 6 and 7 are the perspective views of the loading mechanism in the prior art recorded disk playback apparatus, Figs. 8 and 9 are the views from bottom of the prior art slide table structure, Fig. 10 is a perspective view for illustrating the locking/unlocking mechanism of the slide table due to the prior art, Fig. 11 is a perspective view of a first embodiment of the loading mechanism in the recorded disk playback apparatus in accordance with the present invention, Fig. 12 is a explanatory perspective view of the carriage section of Fig. 11, Figs. 13 to 15 are the simplified diagrams for illustrating the loading operation according to the present invention, Figs. 16 to 19 are the simplyfied diagrams for illustrating each of the modifications to the embodiment shown in Fig. 11, Fig. 20 is an overall perspective view of a second embodiment of the recorded disk playback apparatus in accordance with the present invention, Fig. 21 is a perspective view of the carriage section of the present invention, Figs. 22 and 23 are the front perspective views of the main chassis of the present invention, Fig. 24 is an explanatory crosssectional view of parts of the present invention, Figs. 25 and 26 are the explanatory diagrams for the loading operation due to the present invention, Fig. 27 shows diagrams for illustrating the operation of the carriage and the rack of the present invention, Figs. 28 to 30 are simplified diagrams for illustrating the modifications to the motor and speed reduction mechanism used in the present invention, Figs. 31 to 33 are the diagrams for illustrating the locking mechanism of the sub-chassis in accordance with the present invention, Figs. 34 and 35 are a perspective view and a partial explanatory view of the sub-chassis in accordance with the present invention, Figs. 36 and 37 are explanatory diagrams for loading operation in accordance with the present invention, Fig. 38 is a perspective view of a third embodiment of the present invention, Fig. 39 shows an explanatory diagram for the operations of the carriage and the rack in the second embodiment of the present invention, Fig. 40 is a disassembled perspective view of the locking mechanism for the slide table of the present invention, Fig. 41 shows front views for illustrating the locking/unlocking operation of the slide table of the present invention, and Fig. 42 shows front views for illustrating the operation of a modification to the present invention. Referring to Figs. 11 to 15, there is shown a recorded disk playback apparatus embodying the present invention with reference numeral 120. As shown in Fig. 11, the recorded disk playback apparatus 120 includes a slide table 122 which, differing from the prior art slide table, is formed in a united body with a lifter, and slides back and forth with respect to the main chassis 124, without being lifted/lowered. A sub-chassis 126 provided separately from the main chassis 124 is supported turnably in the rear of the main chasis 124 with a pin 128 as the fulcrum. A turn table motor 20 is fixed to the sub-chassis 126, and a turn table 16 mounted on the upper end of the turn table motor 20 and a center spindle mounted on the turn table 16 are arranged to rotate as a unified body with their respective central axis coinciding to each other. A motor 132 is for turning upward/downward the sub-chassis 126, and its rotation is transmitted, via a small pulley 134 which is connected directly to the motor 132, a belt 136, and a large pulley 138, by means of a worm gear 140, a worm wheel 142, a crank arm 144, and a pinion 146, to a pinion gear 148. The pinion gear 148 is always engaged with a rack 150 which is furnished at the front end of the sub-chassis 126 so that the sub-chassis 126 is made to be raised or lowered by this arrangement. A disk clamper 24 is mounted on a center stay 152, which is fixed to the main chassis 124 spanning both sides of the main chassis 124, to be free to turn, at the position exactly above the center of the disk. A carriage 156 which acts to move a pick-up head 154 for reading and playback recording, in the radial direction of the disk, is furnished on the sub-chassis 126. Next, in Fig. 12 there is shown in detail the part of the apparatus which guides the carriage 156 back and forth. A roller 158 which is attached rollably on one side of the carriage 156 is guided by a guiding rail 154 that is formed on the edge of the same side of the sub-chassis 126, while there is formed an axle bearing 160 on the other side of the carriage 156, and a guidig rod 162 with its one end fixed to the sub-chassis 126 is inserted in the axle bearing 160 to facilitate the feeding operation of the carriage. In addition, on the carriage 156 there is provided a rack 164 for receiving the transmission of the feeding drive, and the rotation of a feeding drive motor 166 is transmitted to a pinion gear 178 which is geared into the rack 164, via a small pulley 168, a belt 170, a large pulley 172, a worm gear 174, and a worm wheel 176, to execute the feeding operation. Next, the operation of the first embodiment according to the present invention will be described by referring to Figs. 13 to 15. To load the disk 14, the disk 14 is placed on the turn table 122 in the state where the turn table is pulled out as shown by Fig. 13, then the slide table 122 is pushed in as in Fig. 14. In the state of Figs. 13 and 14 in which the slide table 122 is pulled out and pushed in, the sub-chassis 126 pivots in the direction of the arrow under the drive of the motor 132 (see Fig. 11), and the turn table 16 is in a position where it is lowered, making it possible for the slide table 122 and the disk 14 to pass through. When the slide table 122 is closed, the motor 132 shown in Fig. 11 is started to rotate the pinion gear 148 whose rotation is transmitted to the rack 150 of the sub-chassis 126, moving the sub-chassis 126 in the direction of the arrow with the pin 128 as the pivot axis, as shown by Fig. 15. By this operation, the turn table 16 is raised, lifting the disk 14 on the slide table 122 from down below, pushing the disk against the disk clamper 24, so that the disk 14 is clamped between the turn table 16 and the disk clamper 24, completing the loading of the disk. In unloading the disk, the reverse operation as for loading the disk is carried out. Namely, as shown in Fig. 15 to Fig. 14, turn table 16 is lowered along with the lowering of the sub-chassis 126, leaving behind the disk 14 on the slide table 122, making it possible for the slide table 122 and the disk 14 to be pulled out. Then, as in Fig. 13, the slide table 122 is pulled out, and the disk 14 is taken out. As described in the above, in contrast to the prior art apparatus which requires both of the mechanism for raising/lowering the lifter 18 and the mechanism for raising/lowering the disk clamper 24, it became possible to carry out disk loading with a simplified mechanism which raises/lowers the sub-chassis 126 alone by pivoting it. Accordingly, the present embodiment makes it possible to diminish the number of parts required, bringing about such favorable effects as a reduction in the size, weight, and cost of the apparatus and an improvement in the productivity. Next, modifications to the embodiment of the recorded disk playback apparatus shown in Fig. 11 will be described by referring to Figs. 16 to 19. In the modifications shown in Figs. 16 and 17, a roller 180 is provided as freely rotatable at the front end of the sub-chassis 126. At the point making a direct contact with the roller 180, a sloped cam 184 that is engaged with a gear 182 is installed as slidable in the back and forth direction of the apparatus. Further, the sub-chassis 126 is energized downward by a spring 186. With this arrangement, when the gear 182 is rotated by a loading drive motor (not shown) and the sloped cam 184 is slided toward the rear, the roller 180 slides down the slope of the sloped cam 184, causing the sub-chassis 126 to pivot downward with the pin 128 as the fulcrum, lowering the turn table 16. On the contrary, when the sloped cam 184 slides forward, the sub-chassis 126 pivots upward, raising the turn table 16, so that loading/unloading of the disk can be accomplished. In the modification shown by Fig. 18 which makes use of an eccentric cam 188 instead of the sloped cam 184, a roller 190 installed on the sub-chassis 126 as freely rotatable is arranged to keep direct contact for all times with the eccentric cam 188. Therefore, when the roller 190 is contacting with the portion of periphery of the cam which is the farthest from the center of the cam, the sub-chassis 126 is at a position of being raised, and when, by the rotation of the eccentric cam 188, the roller 190 makes contact with the portion of periphery of the cam which is the nearest to the center of the cam, the sub-chassis 126 finds itself in the lowered position. In this way, by rotating the eccentric cam 188 by a loading drive motor 192 via a speed reduction mechanism, the sub-chassis 126 is rotated to go up and down with the pin 128 as the fulcrum, and the turn table 16 is raised/lowered. In carrying out this motion, it can be made to take place smoothly if the sub-chassis 126 is energized downward by means of a spring 186. Here, an eccentric cam may be replaced by an elliptic cam, a heart-shaped cam, and so on, as long as the distance from its center to the periphery is not constant. In the modification shown in Fig. 19, one end of a bent revolving lever 196 is supported by a slit 194 which is created at the front end of the sub-chassis 126, and the other end of the lever is supported by one end of a linking rod 198. when the loading drive motor 192 starts operation, a worm wheel 200 rotates via a speed reduction mechanism, and a linking rod 298 which is connected to the worm wheel causes to rotate the revolving lever 196. when the revolving lever 196 rotates in the counterclockwise direction in the figure, the sub-chassis 126 pivots downward with the pin 128 as the fulcrum, and when the revolving lever rotates in the clockwise direction, the sub-chassis 126 pivots upward. In this manner, by pivoting the sub-chassis 126 over a small angle in either one of these methods, it becomes possible to carry out the operations of loading and unloading of the disk by the use of a simplified mechanism, without requiring the raising/lowering action of the lifter 18 and the disk clamper 24 as was the case for the prior art. In particular, when the sloped cam 184 is utilized, the disk can be clamped stably against vibrations in either of the lateral or longitudinal direction since the base of the sloped cam 184 can be kept stable for all times by making contact with the main chassis 124. In Fig. 20 is shown another embodiment of the playback apparatus in which a set of motor and a speed reduction mechanism for the motor are arranged to carry out the loading/unloading drive and the feeding drive for the pick-up. In Fig. 20, the sub-chassis 126 is pivotably attached to the main chassis 124 with pins 128a and 128b at two points on one of its ends. Further, installed on the sub-chassis 126 are the turn table motor 20 on which is mounted the turn table 16 that rotates with the disk on it, and the carriage 156 which moves in the radial direction of the disk with the incorporated pick-up head 154 for reading and playback the signals. Differring from the prior art apparatus, the slide table 122 here is formed in a unified body without requiring an ascent/descent of the part on which the disk is placed. In the space above the turn table 16 there is installed a disk clamper 24 on the center stay that is fixed to the main chassis 124 in a manner to be able to rotate with the disk in one body during the playback operation. The rotation of a motor 200 which serves for both of the loading drive for the disk and the feeding drive for the pick-up head, is reduced by a speed reduction mechanism 216 consisting of a small pulley 202, a large pulley 204, a belt 206, a first gear 208, a second gear 210, a third gear 212, and a fourth gear 214, and is transmitted to a pinion 220 that is permanently geared with a rack 218. The reduction gears 208, 210, 212, and 214 and the pulleys 202 and 204 are fixed to the sub-chassis 126 by being incorporated in a bracket 222. Here, the motor 200 may be installed together with the speed reduction mechanism 216 either on the sub-chasis 126 or on the main chassis 124. The belt 206 which is stretched between the motor 200 and the pulley 204 is arranged to be relatively flexible so that the mechanism for transmitting the rotation will be little affected even when due to the pivoting over a small angle of the sub-chassis 126, there is a slight change in the relative position between the motor 200 installed on the chassis side and the pulley 204 which is on the sub-chassis 126 side. In order to raise/lower the sub-chassis 126 by rotation, the arm 232 at one of the ends of a metallic crank 228 which is supported as revolvable in a bracket 226 that is fixed to the main chassis 124, is inserted in a slit 224 that is provided at the front end of the sub-chassis 126. The arm 230 at the other end of the metallic crank 228 is positioned so as to make a direct contact with the head section 234 of a rack 218 during the time of loading and unloading the disk. Although it is not shown in Fig. 20, the sub-chassis 126 is always being biased in the direction in which the turn table 16 is to be raised, by means of a spring 236. (See the spring 236 shown in Figs. 25 and 26.) Furthermore, the push-back mechanism 238 for carrying out the pushing-out of the slide table 122 is given the following construction. Namely, the push-back lever 242 with a freely rotatable roller 240 is installed at the rear of the main chassis 124 as freely pivotable with a supporting pin 244, and one of its ends is arranged to be pulled always in the direction of pushing the slide table 122 out by the force of a spring 246. Therefore, when the locking mechanism (not shown) that has been locking the slide table 122 is released, the turn table 122 is pushed out by the push-back mechanism 238 for about several centimeters, so that it becomes possible to draw it out manually. In Fig. 21, the feeding operation of the pick-up head 154 is carried out with the carriage 156 being guided in the radial direction of the disk by means of a roller 248 that is installed revolvably on the carriage, a guiding rail 250 installed on the sub-chassis 126, and a guiding rod 260 that is inserted in a bearing 252 on the carriage 156. The rack 232 which is installed on the carriage as slidable with more than one (two in this case) long openings 262a and 262b of the rack 232 and the posts 264a and 264b prepared protrudingly on the carriage 156, serves commonly for driving the feeding of the carriage 156 that is fixed to the pick-up head 154 and the loading and unloading operations of the disk. Between a hole 236 that is prepared at one end of the rack 232 and a hole 268 tha is prepared at an end of the carriage 156 is stretched a spring 270. (The role of the spring 270 will be described later.) In Fig. 22, there is shown that a bracket 226 is fixed to the main chassis 124 and a metallic crank 228 is held revolvably on the bracket 226. For loading and unloading the disk, the slide table 122 has to be free to be pulled out, closed, and slided. For this reason, on the main chassis 124 there are prepared guidng rollers that will be described next. In Fig. 23, the rollers 272, 274, 276, and 278 support the slide table in the up and down direction, while the rollers 280 and 282 support the slide table 122 in the right and left directions, to guide the motion of the slide table. In Fig. 24, the guiding rails 284 and 286 for eliminating the deflections in the up and down directions and the guiding rail 288 for eliminating the deflections in the right and left directions, both being prepared on the slide table 122, engage with each of the rollers 274 to 282 to smooth the back and forth sliding motion of the slide table 122 with repsect to the main frame 290 (see Fig. 25) of the playback apparatus. With the above construction for the recorded disk playback apparatus, in the normal state of its rest, the sub-chassis 126 rotates as shown in Fig. 26 to have the turn table 16 in a raised position without having a disk on it. The operation of the present invention takes place in the following order. I) Pulling operation of the slide table First, the set/eject button for the disk of the recorded disk playback apparatus is pressed. Then, the motor 200 shown in Fig. 20 is actuated, its rotation is transmitted to the pinion 220, and the rack 218 which is geared with the pinion 220 moves forward to the front of the main frame 290 of the playback apparatus. Here, the carriage 156 is restrained by a stopper 292 from moving further forward, so that the rack 218 alone moves forward, with the spring 270 being stretched. Then, the posts 264a and 264b on the carriage 156 slide in the long openings 262a and 262b of the rack 218 from their front end to the rear ends. In this operation, the head section 234 of the forward moving rack 218 pushes the arm 236 of the metallic crank 228, and revolves the metallic crank 228 to lower the sub-chassis 126. When the metallic crank 228 inclines completely toward the lower front, the rotation of the motor 200 is stopped by the action of a first microswitch (not shown), the lock (not shown) on the slide table 122 is released at the same time with the completion of the descent of the sub-chassis 126, and the roller 240 on the push-back lever 242 shown in fig. 20 pushes out the slide table 122 by the force of the spring 246. Then, the slide table 122 is pulled out for an amount which is sufficient for taking in and out of the disk. II) Loading operation of the disk The disk is placed on the slide table 122 as shown in Fig. 25, and the slide table 122 is pushed in. When the slide table 122 is closed, the slide table 122 is locked, when a second microswitch (not shown) is actuated to start the motor 200 shown in Fig. 20, and the rack 218 which is geared with the pinion 220 shifts to the rear of the main frame 290 of the playback apparatus as illustrated by Figs. 25 to 26. At this time, the sub-chassis 126 which is being pulled upward by the spring 236 receives a force that causes it to pivot in the upward direction of the main frame 290 of the playback apparatus with the pins 128a and 128b as the supporting axes. Therefore, by the recession of the rock 218 the sub-chassis 126 pivots as shown by Fig. 26, shifting the arm 230 of the metallic crank 238 to the other position because of its linkage. As the sub-chassis 126 pivots, the disk 14 is lifted by the turn table that is being raised, and is pressed by the disk clamper 24. When the turn table 16 is raised to a fixed position by the pivoting of the sub-chassis 126, the rotation of the motor 200 is interrupted by the action of a third microswitch (not shown). In this manner, the disk 14 is clamped between the turn table 16 and the disk clamper 24, completing the loading of the disk. III) Playing operation In the state as represented by Fig. 26 in which loading of the disk is finished, the posts 264a and 264b of the carriage 156 are situated approximately at the front ends of the long openings 262a and 262b on the rack 218. By pressing the play button in this state, the motor 200 shown in Fig. 20 is actuated, transmitting its rotation to the pinion 220, and sending the rack 218 toward the rear of the main frame 290 of the playback apparatus. Until there is no gap left between the posts 264a and 264b and the long openings 262a and 262b, the carriage 156 with the pick-up head placed on it, as shown by Fig. 20, moves solidly with the rack 218, realizing a playback state. In Fig. 26 is shown the state in which the carriage 156 is situated at the position of the innermost periphery of the disk 14, and the pick-up head 154, too, is at the initial state of the running stroke. During the playback, the carriage 156 moves from the position of the innermost periphery to the outermost periphery of the disk 14. IV) Unloading operation of the disk Not to mention the state of completion of playback in which the carriage 156 is brought to the outermost periphery of the disk 14, when the stop button is pressed in the state of playback even during the feeding stroke of the carriage 156, the rack 218 is sent back to the innermost periphery position of the disk. Then, together with the rack 218, the carriage 156 is returned to the starting position for playback by the pulling force of the spring 270. The carriage 156 then makes a direct contact with the stopper 292. When a direct contact is accomplished, the rotation of the motor 200 is interrupted by the action of a fourth microswitch (not shown), stopping the shift of the rack 218, and hence also of the carriage 156. When the set/eject button is pressed in this state, the motor 200 is actuated and the rack 218 is moved to the front of the main fray 290 of the playback apparatus. Since, however, the carriage 156 is held back by the stopper 292, the posts 264a and 264b on the carriage 156 slide from the front ends to the rear ends of the long openings 262a and 262b on the rack 218, and the rack 218 alone is moved. The head section 234 of the rack 218 pushes the arm 230 of the metallic crank 228, and causes the sub-chassis 126 to go down with the pins 128a and 128b as the fulcrums. At the moment when the metallic crank 228 is pushed completely to the lower front, the first microswitch (not shown) is actuated to interrupt the rotation of the motor, and at the same time with the completion of the descent of the sub-chassis 126, the lock (not shown) on the slide table 122 is released, and the roller 240 on the push-back lever 242 shown in Fig. 20 pushes out the slide table 122 by the force of the spring 246. This makes it possible to take out the disk 14. Next, the operation of the rack 218 and the carriage 156 will be described using Fig. 27 by making reference to Figs. 20 and 21. Figure 27(A) shows the state in which the rack 218 is at the front end of the main frame 290 of the playback apparatus and the sub-chassis 126 is lowered. When the slide table 122 is closed, the motor 200 is actuated, its rotation is transmitted to the pinion 220, and the rack 218 slides to the rear of the main frame 290 of the playback apparatus. At this time, the posts 264a and 264b that are set on one side of the carriage 156 slide from the rear ends of the front ends of the long openings 262a and 262b on the rack, sliding continuing until at least either one of the posts 264a and 264b makes a direct coantact with the front end of the long opening 262a or 262b. With this operation, the sub-chassis 126 is raised as described before, making it possible to carry out the loading of the disk. Figure 27(B) shows the state in which the carriage 156 of the rack 218 is at the starting position of playback. When the play button is pressed in this state, the rack 218 slides to the rear of the main frame 290 of the playback apparatus, and the carriage 156 interlocks with the rack 218 since the posts 264a and 264b are making direct contact with the long openings 262a and 262b. Since the pick-up head 154 is fixed to the carriage 156, the pick-up head 154 moves in one body with the carriage 156 from the innermost periphery to the outermost periphery of the disk 14, carrying out the playback. Figure 27(C) shows the state in which the rack 218 and the carriage 156 are in the positions corresponding to the completion of playback. When the stop button is pressed in this state, the rack 218 moves to the front of the main frame 290 of the playback apparatus, and being interlocked with the rack 218 the carriage 156 slides to the front of the main frame 290 of the playback apparatus, pulled by the elastic force of the spring 270 that is stretched between the hole at the front end of the rack 218 and the hole at the rear end of the carriage 156. Figure 27(D) shows the state in which the rack 218 and the carriage 156 are returned to the starting position of playback. In this state, the carriage 156 is held back by the stopper 292 from moving any further into the front from that position. When the eject button is pressed in this state, the rack 218 slides further forward, due to the constraint on the carriage 156 by the stopper 292, the rack 218 alone slides forward, stretching the spring 270. Then, by the push given by the head section 234 of the rack 218 on the am 230 of the metallic crank 228, the sub-chassis 126 goes down, permitting the unloading of the disk 14. In addition, although the spring 270 is used in the above description for interlocking the carriage 156 and the rack 218, it may be replaced by anything, such as an elastic body like rubber, as long as it serves a similar function. As described in the foregoing, since a sub-chassis is provided and the disk receiving section is formed into a unified body with the slide table, the required operation becomes possible to be carried out without the use of a lifter, a mechanism such as cams and links for raising/lowering the lifter, and a mechanism for raising/lowering the disk clamper, leading to an improvement in the reliability of the apparatus. Moreover, in Figs. 28 and 29 there are illustrated the cases in which the speed reduction mechanism 216 for the motor 200 which serves commonly for loading drive and pick-up head feeding is replaced by the use of a worm gear. In Fig. 28, the center axes 298 and 300 of the worm gear 296 and the motor 200, respectively, are arranged both in perpendicular direction. In Fig. 29, the center axes 302 and 304 of the worm gear 296 and the motor 200, respectively, are arranged both in horizontal direction, with a simplified diagram of the rack 306 as shown by Fig. 30. Compared with the apparatus shown in Fig. 20 in which use is made of a combination of flat gears, both of the apparatus in Figs. 28 and 29 permit to reduce the number of parts and the space required for the speed reduction mechanism. Figures 31 to 33 illustrate the mechanism by which the main chassis 124 is locked during the playback operation to prevent the lowering of the sub-chassis 126. The raised state of the sub-chassis 126 is maintained by the elastic force of the spring 236 shown in Figs. 25 and 26. If vibrations or shocks in the vertical direction are applied to the apparatus, it is possible that the turn table 16 which holds the disk 14 on it is displaced downward. In extreme cases, there exists a fear of damaging the disk 14 or the playback apparatus caused by the contact between the disk 14 in rotation and the slide table 16. This is the reason why the sub-chassis 126 is locked to prevent its descent during the playback. As shown in Fig. 31, a locking lever 312 is fit to a post 310 which is provided in the tip area of the sub-chassis 126, energized by a spring 314 in the clockwise direction gas seen from the top of the main frame 290 of the playback apparatus. On one end of the locking lever 312 there is formed a projection 316 to be used for locking. At the raised position of the sub-chassis 126, there is prepared a slit 318 on the main chassis 124 side, as shown in Figs. 32 and 33, at the position facing the projection 316. The other end of the locking lever 312 is linked to the connecting rod 320, and when the sub-chassis 126 is displaced by turning, as shown by Fig.32, the connecting rod 320 is pushed by the pick-up head 154, regulating the turning of the locking lever 312. In the reproducible state as shown by Fig. 33, the carriage 156 with the pick-up head 154 placed on it is shifted to the rear of the main frame 290 of the playback apparatus, so that the connecting rod 320 is released and the locking lever 312 turns in the clockwise direction as seen from the top of the main frame 290 of the playback apparaus. Then, the projection 316 on the locking lever 312 enters the slit 318 prepared on the main chassis 124, locking the sub-chassis 126 to prevent its descent. In this manner, it is possible to obtain a safe and highly reliable playback apparatus by securely locking the disk in the loaded state, during the playback operation with the rotating disk 14, to prevent damages to the disk 14 or the playback apparatus that may be caused by unexpected vibrations or shocks. In Fig. 34 is shown the case in which a cam 322 is used in place of the slit that is provided as shown in Fig. 20 at the tip of the sub-chassis 126. In accordance with this, the metallic crank 228 is given the shape as shown by Fig. 35 in which the arm 230 of the metallic crank 228 is at the position that makes a direct contact with the cam 322. On the cam 322 there is provided, as shown by Fig. 35, a locker 324, for preventing the descent of the sub-chassis 126 from the state of its raised position, which is caught by the arm 230 of the metallic crank 228. Figures 36 and 37 describe the operating states of the above arrangement. In the figures, the parts that are identical or equivalent to those in Figs. 25 and 26 are given the same symbols to omit further explanation. When the metallic crank 228 rotates with the revolving fulcrum 228 of the metallic crank 228 as axis, by being pushed by the rack 232 as shown by Fig. 36, the arm 230 of the metallic crank 228 rotates while pushing the curved slope 322a of the cam 322, causing the sub-chassis 126 to descend while turning. Next, when the slide table 122 is closed as in Fig. 37, the rack 232 moves to the rear of the main frame 290 of the playback apparatus, the metallic crank 228 is turned in this motion toward the front side of the main frame 290 of the playback apparatus, so that the arm 230 of the metallic crank 228 is made to descend along the curved slope 322a of the cam 322, raising the sub-chassis 126. In the state of completed ascent, the locker 234 is held at the position where it is caught and stopped by the arm 230 of the metallic crank 228 even when there is applied a force which could cause the sub-chassis 126 to descend. Furthermore, the forms of the metallic crank 228 and the cam 322 and the configuration between them are designed, even when vibrations or shocks are applied to the arm 230 of the metallic crank 228 in the vertical direction, to avoid that the point of action and the direction of the relevant force generate a rotational moment, with respect to the turning fulcrum 228 of the metallic crank 226, which tends to turn the metallic crank 228 in the direction from the rear to the front of the main frame 290 of the playback apparatus. By this arrangement the rotation of the sub-chassis 126 in the direction off its descent is restrained. It is known that in the ascent of the sub-chassis 156, a satisfactory result can be obtained by energizing the metallic crank 228 toward the rear of the main frame 290 of the playback apparatus by means of a weak spring, though the figure is omitted, in order to make a smooth descent of the arm 230 of the metallic crank 228 along the curved surface 322a. Also, a smoother operation is known to be obtained by giving a roller structure to the arm 230 of the metallic crank 228. With a mechanism like in the above, even when strong vibrations or shocks are applied in the vertical direction to give a force to lower the sub-chassis 126, after the disk 14 was started to rotate, the descent of the sub-chassis 126 is restrained, and makes it possible to avoid injuries or damages that may be caused by the contact of the disk 14 in rotation with the slide table 16, creating a stable and highly reliable playback apparatus. Next, as another embodiment of the present invention, a mechanism which includes a slide table, a lifter, and an ascent/descent cam will be described by referring to Figs. 38 and 39. In Fig. 38 is shown an apparatus in which one motor is served commonly for loading drive and pick-up head feeding. The parts that are identical or equivalent to the prior art components as shown in Fig. 20 are given identical symbols to omit further explanation. A rack 326 is one in which the entire range of one side of the rack 46, used for the recorded disk playback apparatus shown in Fig. 6, is made into a gear 328 to permit a wide range of slide. The rack 326 is geared with a pinion 330 which extends downward from the lower part of the main frame 290 of the playback apparatus. The reason for this is to avoid contact of a newly installed carriage 332, while it is moving, with the motor 334 and others, by extending the pinion 330 into the lower section of the main frame 290 of the playback apparatus where a space is available. A post 338 erected at the tip of the arm 336 of the carriage 332 is inserted slidably into a long opening 340b on the rack 326 so that the carriage 332 is slidable back and forth with respect to the main frame 290 of the playback apparatus. In addition, between a hole 342 prepared in the arm 336 of the carriage 332 and a hole 354 prepared at the tip of the rack 326, there is stretched a spring 346 which gives an operating effect which is similar to that of the spring 270 shown in Figs. 20, 21, 25, 26, and 27. ON the side of the carriage 332 opposite to the side on which is installed the arm 334, there are provided guiding pieces 348 which help the carriage 332 to be slided stably, guided by a guiding rod 350. The guiding rod 350 is fixed by means of a fixing piece 352 and a pin 354. The pick-up head 154 is fixed to the carriage 332 to move solidly with the carriage 332, and shifts during playback from the innermost periphery side to the outermost periphery side of the disk 14. The operation of an apparatus with such a construction will now by described by referring to Figs. 38 and 39. Figure 39(A) illustrates the state in which the disk clamper 24 is raised without clamping the disk 14. In this state, the motor 334 is actuated to transmit its rotation to the pinion 330, and the rack 326 slides from the state in which it is situated at the rear (direction to the right of the figure) of the main frame 290 of the playback apparatus, with the spring 346 being stretched, to the state in which the spring 346 is being returned to its original state and at least either one of the posts 356 and 338 makes a direct contact with the front end (left end in the figure) of the long opening 340a or 340b. During this period, loading of the disk is accomplished. However, the operation involved is entirely the same as in the playback apparatus shown in Figs. 1 through 9 so that no further explanation will be given here. Figure 39(B) shows the state in which the rack 326 is in the starting position of playback where the rack 326 is slided to the rear of the main frame 290 of the playback apparatus by the rotation of the pinion 330. Since in this state the posts 356 and 338 are making direct contact with the front ends of the long openings 340a and 340b, the carriage 332 with the pick-up head 154 placed on it is also shifted toward the rear of the main frame 290 of the playback apparatus, that is, from the innermost periphery to the outermost periphery of the disk 14. Figure 39(C) illustrates the situation in which the pick-up head 154 is shifted to the outermost periphery of the disk 14, indicating that playback is completed. Figure 39(D) shows that the starting position for recording is resumed for unloading the disk. In this state, the rack 326 is shifted to the front of the main frame 290 of the playback apparatus, and the carriage 332, being interlocked with the rack 326, is also shifted up to the position where it makes a direct contact with the stopper 360 under the elastic force of the spring 346 stretched between the hole 344 prepared at the tip of the rack 326 and the hole 342 prepared on the arm 336 of the carriage 332. Later, when the switch for taking out the disk 14 is operated, the rack 326 slides further toward the front of the main frame 290 of the playback apparatus. Here, the carriage 332 is held back by the stopper 360 so that the rack 326 alone is shifted, stretching the spring 346. When the shift is made to the position as indicated by Fig. 39(A), the operation for unloading the disk 14 is completed. The operation during this period is exactly the same as in the playback apparatus shown in Figs. 1 through 9 which has already been described so that further explanation will be omitted here. In Fig. 40 there is shown a disassembled perspective view of the embodiment of the locking/unlocking mechanism for the slide table in accordance with the present invention. The locking/unlocking mechanism is for ensuring the locking of the slide table 122 within the playback apparatus without being pulled out, during the loading operation of the disk where the slide table 122 is pushed into the playback apparatus, as shown by Fig. 25, or during the playback operation following the loading. The locking/unlocking mechanism for this purpose due to the present invention is arranged to have a construction in which the release of the slide table is carried out without the use of a large-power solenoid which was the case in the prior art. In Fig. 40, three pins 364, 366, and 368 are erected on the locking mechanism bracket 362, and the locking lever 370 is fitted to the pin 364 by being energized by a spring. A holding lever 374 is linked to the pin 366, being energized by a spring 376. On the unlocking lever 380 there is erected a pin 382 to which is linked an unlocing ratchet 384, energized by a spring 386 in the counterclockwise direction as seen from the top. In Fig. 20 at the rear of the main frame, there are installed a push-back lever 242 for providing a force to push back the slide table 122, a supporting pin 244, a push-back spring 246, and a roller 240. Also, at the position exactly above the turn table 16, there is mounted the disk clamper 24 at the center of a reinforcing component 152 that spans the left and right sides of the chassis 124. The disk clamper 24 is arranged to clamp the disk between it and the turn table, and to be able to rotate with the disk and the turn table in a unified body. The operation of the apparatus with the above construction will be described in what follows. In the normal state of rest, the playback apparatus will be found in the position in which the turn table is raised, as shown in Fig. 26, without having the disk on it, and the slide table 122 is in the state of being pushed in the playback apparatus and is locked there. In order to pull out the slide table 122 from this state, the button for taking out the disk is pressed. Then, the motor 200 is actuated to move the rack 218 forward, to let the rack to push the arm 230 of the metallic crank 228 to the forward direction, lowering the sub-chassis 126. Just before the lowering of the sub-chassis is completed, the arm 230 of the metallic crank 228 pushes the unlocking lever 380 as in Fig. 41(d), turning it in the clockwise direction as seen from the top, changing the situation from what is shown in Fig. 41(d) to what is in Fig. 41(a). Next, the unlocking ratchet 384 on the unlocking lever 380 causes the locking lever 370 to revolve in the counterclockwise direction, and the unlocking lever 370 releases the holding of the locking post 398 on the slide table 122. Then, the rotation of the motor 200 is interrupted. With this, the slide table 122 is pushed forward by the action of the push-back arm 388 to permit the slide table to be taken out. Now, there are two cases in which the slide table 122 is pulled out, namely, the case of taking out the disk from the playback apparatus and the case of unloading the disk. The mechanical operations of the playback apparatus for these cases are identical except for the presence or absence of the disk. Next, there are two cases in which the slide table 122 is pushed in, namely, the case where the slide table is pushed in after the disk is removed and the case where the disk is going to be loaded. In these cases, too, the mechanical operations inside the playback apparatus are identical except for the presence or absence of the disk. When the slide table 122 is closed, the holding lever 374 recedes by being pushed by the locking post 400 of the slide table, as shown by Fig. 41(a). By this, the protuberance 370a (see Fig. 40), which is on the reverse side of the locking lever 370, that is being caught by the holding lever 374 is released from the holding lever 374, turned by the force of the spring 372, accomplishing the locking of the slide table 122 by pressing the locking lever with the locking post 400, as shown by Fig. 41(b). As the motor 200 is actuated by sensing the locking of the slide table with a microswitch (not shown) or the like, the rack 218 starts to recede. Since the arm 230 of the crank recedes also, the turn table 16 is raised as shown in Fig. 4 from the state of Fig. 3, accomplishing the loading when there is a disk. At the same time, the unlocking lever 380 is turned counterclockwise as shown in Fig. 41(c) by the force of the spring 380a as the arm 230 of the crank leaves the state represented by Fig. 41(b). In this process, the unlocking ratchet 384 passes by the tip of the locking lever 370 while being turned from the state shown by the broken line to the state shown by the solid line in Fig. 41(c). By now the preparation is complete for unlocking the slide table 122. When the unlocking arm 230 is pressed again by the arm 230 of the crank, the unlocking action is carried out as from Fig. 41(d) to Fig. 41(a). As described in the above, in the present invention an unlocking mechanism with an unlocking ratchet is employed which is driven by the use of the power for loading/unloading, instead of a solenoid and an arm for transmitting the suction power of the solenoid to the locking plate. This makes it possible to obtain a disk loading mechanism which is less expensive and small both in size and weight by doing away with expensive parts. In Fig. 42 is shown another embodiment of the mechanism. Figure 42(a'), (b'), (c'), and (d') show the operational states of the mechanism which is obtained by deleting the unlock holding lever 105 from the embodiment shown by Fig. 41. When the button for taking the disk out from the playback apparatus is operated to pull out the slide table from the resting state or the playback state of the playback apparatus, the turn table 16 is lowered by the forward push of the crank arm 230 due to the motion of the rack. At the same time, the unlocking lever 380 is pushed as shown by Fig. 42(d') to turn the locking arm 370 in the counterclockwise direction by the unlocking ratchet 384, and releases the holding of the locking post 400 of the slide table as in Fig. 42(a'), pulling out the slide table. When the unlocking ratchet 11 completes its passage by turning the locking lever 370 ends up with the state as represented by the doubly dotted broken line in Fig. 42(a') by the action of the spring 372, since in this embodiment use is not made of the unlock holding lever 374 as in the previous embodiment shown in Fig. 41(a). Following that, when the slide table is pushed in after either placing a disk on the slide table or taking a disk away, the locking post 400 of the slide table moves while pressing the cam slope 370b which is located at the tip of the locking lever 370, and is locked by the locking lever 370 as in Fig. 42(b'). The operations after the above are completely identical to the operations in Figs. 41(b), (c), and (d) so that further explanation will be omitted. In this manner, in the example of Fig. 42, the unlock holding is done away with to simplify the mechanism, contributing markedly toward cost reduction due to cut in the number of the parts used and in the number of assembling steps. Furthermore, similar action and effects as before can be obtained by employing another embodiment, though the figure is omitted, in which the unlocking lever 380 is pushed by the rack 218 instead of by the crank arm 230. In this case, the rack is lowered together with the turn table and others while pressing the crank arm 230 and the unlocking lever 380, so that the form of the tip of the rack that makes a direct contact with the unlocking lever has to be designed in such a way as to avoid slipping of the unlocking lever 380 even when the rack is lowered for some reason. As has been described in detail in the foregoing, the present invention is given a mechanism which does not require the lifting/lowering of the lifter through unification of the slide table and the lifter into one body. With this arrangement, the slide table becomes possible to be made using thin material in view of the strength against a force in the vertical direction, gained by doing away with a large opening to be created in the slide table for letting the lifter to pass through and by the unification between the two elements. In addition, the present invention is given a mechanism in which the disk is clamped between a fixed disk clamper and a turn table whose raising/lowering is achieved by turning a sub-chassis, and in which is incorporated the turn table that can be turned within a small range of angle, by means of a combination of gears, cams, and the like. As a result, a simplification in the mechanism for raising/lowering becoms possible, realizing a reduction in the number of parts required. Moreover, in accordance with the present invention, it is arranged to have, both of the loading/unloading drive for the disk and the pick-up head feeding drive, served commonly by a motor and a set of speed reduction mechanism for the motor, as well as to do away with a large solenoid required in the prior art apparatus, so that it becomes possible to realize a reduction in the size and the weight, and an inprovement in the reliability, of the recorded disk playback apparatus.

Claims: A disk playback apparatus for reproducing information memorized in a record disk (14) by means of a pick-up head (154), comprising: a main chassis (124) which is housed in a main frame of the recorded disk play apparatus; guide means for carrying said record disk (14) and adapted to move into a predetermined position in the apparatus suitable for enabling reproducing operation; a carriage (156) for feeding the pick-up head (154) in the radial direction of the record disk; a turntable (16) for supporting the record disk (14) by clamping it between said turntable and a disk clamper (24); and a turntable motor (20) for turning said turntable (16) together with the record disk (14), said apparatus characterized by a sub-chassis (126), pivotably supported at one end by said main chassis (124) carrying said carriage (156) and said turn table (16), and by driving means and an adjusting mechanism (164, 178) for moving said carriage (156) and for moving said sub-chassis (126) upward/downward, whereby, when said guide means is in said predetermined position, the record disk is clamped by moving said turntable upward by means of said sub-chassis against said disk clamper (24) with the record disk therebetween wherein said disk clamper (24) and the record disk are rotatably fixed with reference to said main chassis. A disk playback apparatus as claimed in claim (1), in which the engagement/disengagement of said disk clamper (24) with respect to the recorded disk that is placed on said turntable (16) is controlled by the raising/lowering of said sub-chassis (126). A disk playback apparatus as claimed in claim 1 or 2, in which the recorded disk that is engaged with said turntable (16) is arranged to be clamped between said disk clamper (24) and said turntable at the time when said sub-chassis (126) attains a predetermined position. A disk playback apparatus as claimed in claim 1, in which said driving means comprises a driving motor which serves commonly for the feeding drive for the pick-up head (154) and the raising/lowering drive for said sub-chassis (126). A disk playback apparatus as claimed in claim 1, in which said adjusting mechanism comprises a rack (326) which moves in the radial direction of the recorded disk under the power of the driving motor, a stopper (292) which defines the moving range of said carriage (156, 332), a linking mechanism which makes it possible to link the rack and the carriage within the moving range of said carriage, and a raising/lowering mechanism which turns upward/downward said sub-chassis in association with the shifting motion of the rack. A disk playback apparatus as claimed in claim 5, in which the linking mechanism is arranged to make the rack (326) alone movable when the motion of said carriage (156, 332) is regulated by the stopper (292), and to make the linkage between the rack and said carriage possible when the regulation of the stopper on said carriage is released. A disk playback apparatus as claimed in claim 5 or 6, in which the raising/lowering mechanism turns upward/downward said sub-chassis (126) in association with the shifting motion of the rack when the motion of said carriage is regulated by the stopper (292). A disk playback apparatus as claimed in claim 7, in which said linking mechanism comprises long openings (340a, 340b) prepared in the rack and protuberances (338) that are mounted on said carriage (332) as freely movable in the long openings in the rack, and a linkage between said carriage and the rack being achieved only when the long openings in the rack and the protuberances on said carriage are joined with direct contact. A disk playback apparatus as claimed in any of claims 5 to 8, in which said raising/lowering mechanism comprises a slit (224) prepared at the front end of said sub-chasssis (126), a metallic crank (228) held revolvably by a bracket fixed to said main chassis, and an elastic component (236) which energizes said sub-chassis (126) for all times so as to turn it in the direction in which said turn table is to be raised, and one end of the metallic crank is linked to the slit, while the other end of the crank is prepared at a position where is makes a direct contact with the rack, and it being arranged to lower the sub-chassis in association with the shifting motion of the rack alone. A disk playback apparatus as claimed in any of claims 5 to 9, wherein said guide means comprises; a slide table (122) for transporting the recorded disk to the position which coincides with the center of rotation of said turntable; and further comprising a locking/unlocking mechanism which locks/unlocks said slide table in association with the shifting motion of the rack, A disk playback apparatus as claimed in claim 10, in which said locking/unlocking mechanism is equipped with a locking lever (370) which holds the slide table (122) at the housing position of the playback apparatus by linking the slide table (122) with a locking post (400) prepared on said slide table, an unlock holding lever (374) which holds the locking lever at its released position, and an unlocking lever (380) which is moved by the shifting motion of the rack during the loading/unloading of the disk, and one end of the unlocking lever being provided with an unlocking ratchet (384), while the other end of the unlocking lever is moved by the driving means to cause the unlocking ratchet to move solidly with the unlocking lever and cause the locking lever to move to its unlocking position by the unlocking ratchet, during the loading operation in such a manner that, even when the unlocking lever is moved, it will not affect the locking lever due to the dodging turn of the unlocking ratchet. A disk playback apparatus as claimed in claim 10, in which said locking/unlocking mechanism is equipped with a locking lever (370) which holds the slide table (122) at the housing position of the playback apparatus by linking the slide table with a locking pin (398) prepared on the slide table, and an unlocking lever (380) which is moved by the rack of the driving means that is shifted during the loading/unloading of the disk, and on one end of the unlocking lever (380) there being provided an unlocking ratchet (384), while the other end of the unlocking lever is moved by the parts of the driving means to be moved solidly with the unlocking lever (380), the unlocking ratchet moving the locking lever (370) to its unlocking position, the locking lever being not affected during the loading operation, even when the unlocking lever (380) is moved, because of the dodging turn of the unlocking ratchet, and it being arranged that a locking pin (400) on the slide table (122) rides across and presses the cam slope at the tip of the locking lever, to be locked at the locking lever. A disk playback apparatus as claimed in claim 1 or any preceding claim depending on claim 2 in which said adjusting mechanism further comprises a control mechanism which controls the turning on/off of the driving motor in accordance with the shifted position of said carriage and the raised/lowered position of said sub-chassis. A disk playback apparatus as claimed in any of claims 8 to 11, further comprising: a push-back mechanism (388) for pushing out said slide table at the point in time when the locking of said slide table is released.

Inventors: KOBAYASHI, KOICH
Applicants: KABUSHIKI KAISHA TOSHIBA
Application year: 1985
Main classification: G11B17
IPC codes: G11B17