DUAL DRIVE CHANGER FOR RECORDS

Abstract: The present invention concerns a changer for sequentially retrieving recorded information on a selected record (7) while another previously selected record (7) is being cued or played back so that records (7) may be played back without any interruption, comprising a magazine (3) for storing a plurality of records (7) along a number of planes (30, 31) and two record selections, loading, playback and unloading mechanisms (12, 13), characterized in that the operating planes of said first and second playback mechanisms (12, 13) are placed side by side parallel to each other and, upon selection aligned with a number of planes (30, 31) of the magazine (3) where records (7) are stored in order to allow any record (7) to be played back by any playback mechanisms (12, 13).

Description: The present invention relates to changers for records, such as grooved or optically readable discs on which information is recorded. More particularly, the invention relates to changer apparatus including a magazine for storing a plurality of records and a mechanism for selecting records from the magazine, for retrieving recorded information from a selected record, and for returning the selected records to the magazine. Background Art Various designs of apparatus for changing records, particularly in disc form, are known. The records employ a carrier or medium upon which information is stored for retrieval or playback. Typical examples of records include discs containing grooves of varying widths and depths for playback with a stylus, discs encoded for optical retrieval of information, such as compact discs and video discs, and other analogue and digitally encoded records. Information retrieval from records of particular interest to the invention is accomplished by rotating the record about a central axis and detecting a signal, such as an electrical signal or reflected light, that is converted to a useful information form. In known changers, a record is selected from a library of records, some part or all of the information stored on the record is retrieved, and the record is returned to the library. Subsequently, a second record is selected, the desired information on that record is located and retrieved, and that record is returned to the library. Because of the construction of typical changers for records, there is an interruption or "dead time" between sequential information retrievals or playbacks from different records. The interruption begins at the end of information retrieval from a record, continues while that record is being returned to the library, while a new record is being selected from the library, and until the new record reaches its playback speed and the information desired to be retrieved is located on the record. In audio and/or video record applications, the dead time prevents continuous retrieval of information from different records. Cross-fading from one record to another cannot be achieved. In data retrieval applications, valuable time is lost as a computer or other apparatus to which information is being supplied waits while records in the playback mechanism are being changed. Several designs have been proposed to reduce the dead time between sequential information retrievals from separate records. For example, in Belgian Patent 898,775 a changer apparatus includes an annular magazine in which records are stored. A mechanism for selecting records from the magazine, for returning records to the magazine, and for playback of records is mounted on a circular plate within, and having a central axis coincident with that of, the magazine. Rotation of the plate positions the record selection and return apparatus opposite a selected disc for its retrieval and playback. However, some dead time occurs between the ending of playback of one record and the beginning of the playback of a second record. During that dead time, the first record is returned to one position in the magazine and the second record is selected from a different position in the magazine. In a changer for magnetic tape cassettes disclosed in West German Auslegeschrift 21 16 028, playback mechanisms are provided on opposite sides of a magazine that rotates about a generally horizontal axis. That arrangement permits the selection of a cassette and the cueing of the tape in that cassette by one of the playback mechanisms while the other playback mechanism is retrieving information from a previously selected cassette. That changer avoids dead time interruptions between sequential information retrievals, but its design is difficult to apply to discs. Magnetic tape cassettes may be conveniently fitted with notches or other engaging means to aid selection, whereas circular discs cannot be similarly notched. Moreover, the circular shape of discs implies that a disc changer analogous to the German application tape cassette player would occupy a large volume. In that analogue, space for three side-by-side discs (one in each playback mechanism and one in the interposed magazine) would be required. Further, the cassette disclosed in the German patent publication is not suitable for use with discs. In a magazine rotating about a horizontal axis like that in the publication, discs are presented without discrimination between sides, and discs could be displaced from the magazine during rotation of the magazine about its axis. Finally, document JP-A-60/131672 discloses a changer for sequentially retrieving recorded information on a selected record having a rotary magazine and two loading and playback mechanisms located above said magazine. Said mechanisms have their loading and operating planes in one common radial plane and are disposed in a "mirror" position with respect to each other. The only purpose of the second playback mechanism is to assure the reproduction of the other or rear side of the disk. Thus, each of said playback mechanisms is arranged to reproduce only one out of the two sides of an optical disk. The outside dimensions of the proposed arrangement, having the playback mechanisms located above the magazine, are very large. Furthermore said document does not provide any solution to assure a sequentially playback of freely selected records without any interruption. Disclosure Of The Invention It is, therefore, an object of the invention to provide a simple changer for records, particularly for discs, that is free of dead time and has a size that does not exceed the outside dimensions of a magazine for storage of records. Another object of the invention is to provide a changer employing a plurality of similar components to achieve reduced manufacturing costs. The aims of the invention are achieved in a changer as defined in claim 1 and including an annular magazine for storing a plurality of records along a number of planes, all disposed tangentially to a circle concentric with the central axis of the magazine. The novel changer includes two mechanisms for selecting records from the magazine, playing back the selected records to retrieve recorded information, and returning the selected records to the magazine. The mechanisms are preferably mounted within the annular magazine. The mechanisms and magazine are rotatable relative to each other about the central axis of the magazine. The magazine includes storage slots for storing records generally tangentially to a circle concentric with the central axis of the magazine. In a preferred embodiment, the mechanisms are oppositely disposed for receiving and discharging records at opposed locations within the magazine. The operation of the playback mechanisms is independent from their positioning relative to the magazine. Additional features and advantages of the invention will become evident from the following detailed description of a preferred embodiment of the invention. Various additions and modifications within the spirit of the invention will occur to those of skill in the art. Accordingly, the scope of the invention is not limited by the described preferred embodiment. The invention may be more easily understood by reference to the drawing figures in which like elements are given the same reference numbers. Brief Description Of The Drawings Figure 1 is a schematic plan view of an embodiment of a changer apparatus according to the invention. Figure 2 is a sectional side view of the apparatus of Figure 1 taken along its line A-A. Figure 3 is a schematic diagram illustrating the arrangement of slots in a magazine for use with the invention. Figures 4A, 4B, and 4C are, respectively, plan, top, and rear views of an embodiment of a disc playback unit that can be used in the invention. Best Mode For Carrying Out The Invention A preferred embodiment of a changer 1 for records according to the invention is shown in schematic plan and sectional side views in Figures 1 and 2, respectively. The changer includes a supporting frame 2 on which an annular magazine 3 is disposed for storage of records. The magazine 3 has a central opening 4. The magazine also includes a plurality of generally radially disposed walls 5 that are generally perpendicular to the supporting frame 2. A slot or compartment 6 is defined by and between each adjacent pair of the walls 5 in which a record, particularly in the form of a disc 7, may be stored. Each slot 6 is open toward the inside, the outside, and the top of the annular magazine 3. The walls 5 are generally trapezoidal in shape. With that wall shape, the discs 7 within the slots 6 are partially exposed at the outside of the magazine 3 so that they may be manually inserted and removed. The discs 7 may be mechanically transferred out of the magazine 3 through the opening in each slot 6 that is adjacent the inside of the magazine in preparation for playback. The discs 7 may be compact discs of either the conventional three inch or five inch size. In a preferred embodiment of the changer, discs of different sizes may be loaded into the same magazine and played back in any desired sequence. The discs 7 are disposed in the magazine 3 so that gravity urges them toward the outside of the magazine. Between each adjacent pair of walls 5, at the outside of the magazine 3, a stop 8 is provided for retaining discs within the slots 6. The stop 8 prevents rolling of the discs beyond the outside of the magazine 3. A lever 9 having a hook-line end is disposed on the supporting frame 2 of the magazine in each slot 6 for retaining a disc recording 7 in each of the slots 6 and for transferring the disc out of its slot. The lever 9 is shown in Figure 2 in its storage position in contact with the frame 2. The lever 9 is pivotally attached to a pin 10 opposite the hook-like end of the lever. The pin 10 is mounted proximate the central opening 4 of the magazine 3. The lever 9 rotates about the pin 10 when it transfers a disc out of a slot 6 toward the central opening 4 of the magazine 3. Dual mechanisms 11 for receiving records, for playing back, i.e., retrieving information from records, and for ejecting records are disposed within the central opening 4 of the annular magazine 3. The mechanisms 11 include playback units 12 and 13 commonly mounted on a circular plate or base 14 that is rotatable relative to the magazine 3 about a central axis 15. The axis 15 is also the central axis of the magazine 3. The playback units 12 and 13 may be of a conventional construction for receiving a disc edgewise, for engaging the disc with a drive means, for rotating the disc, for retrieving information from the rotating disc, and for ejecting the disc after playback. An example of such a playback unit is described in U. S. Patent 4,546,396, the disclosure of which is incorporated herein by reference. The playback units 12 and 13 may be of the type that accommodates discs of different sizes, such as 80mm and 120mm diameter compact discs. An example of a mechanism of the latter type is disclosed in U. S. Patent 4,498,162, the disclosure of which is also incorporated herein by reference. Still another playback mechanism accepting disc of different sizes and suitable for use in the invention is described below in connection with Figures 4A, 4B, and 4C. Through the relative rotation of the magazine 3 and the plate 14, the playback units 12 and 13 may be positioned so that one of them aligns with a slot 6 containing a desired record. In the embodiment illustrated, the plate 14 is rotated about the axis 15 by a gear 16 that engages an annular rack 17 that is mounted on the top side of the plate 14, on which the mechanisms 11 are mounted. The gear 16 is driven by an electric motor 18, that is mounted on the frame 2. Rollers 20 support the plate 14 and allow it to rotate around the axis 15 on a journalled spindle 21 in response to the turning of the motor 18. In the preferred embodiment, the playback units 12 and 13 and the walls 5 are arranged so that a record can be selected by and transferred to either unit from any slot 6. Preferably, as shown in Figure 1, the playback units 12 and 13 are mounted in opposition; that is, the openings of playback units 12 and 13 for receiving a disc are disposed at opposed locations at the inside of the annular magazine 3. In addition, the playback units 12 and 13 are disposed symmetrically with respect to the central axis 15 of the rotating plate 14 and the magazine 3. Accordingly, the openings of the playback units 12 and 13 are disposed tangentially to a circle that is concentric with the axis 15 and the spindle 21 on which the plate 14 is mounted. It follows that the walls 5 and the slots 6 are likewise disposed tangentially to the same circle that is concentric with the central axis. This arrangement is schematically illustrated in Figure 3. There, the planes of the playback units 12 and 13 for receiving records are illustrated as lines 30 and 31, respectively. Those lines are tangential to a circle 32 that is concentric with the spindle on which the plate 14 is mounted. (Circle 32 is included in Figure 3 solely for clarity of explanation and is not a structural element.) The planes in which the discs are stored are coincident with the planes in which the playback units 12 and 13 receive and eject the discs at the various alignments of the slots 6 and the playback unit. The spacing between the walls 5 is determined by the thickness of the records to be stored between them and the desired capacity of a magazine. That spacing results in a sector angle α for each of the slots 6. For example, the sector angle α may be four degrees. The paths followed by selected recordings as they are selected from, and returned to, the slots 6 lie along a series of lines that lie generally tangential to the circle 32 and that are successively angularly separated by the angle α beginning from the planes 30 and 31, respectively. By employing that spacing arrangement, any record stored in the magazine can be selected from its slot by either of the playback units 12 or 13. In the preferred embodiment, changer operation is controlled electrically through a microprocessor according to a programmed set of instructions. The novel changer following the instructions avoids dead time interruptions between successive retrievals of information from different records. The records may be compact discs, video discs, acoustic sound recordings, magnetic discs, or other types of records. In order to explain operation of the changer, it is assumed that each record has a plurality of numbered tracks and is stored in a numbered slot in a magazine. As an example, suppose the desired sequence of operation requires the playback of track N3 from a compact disc stored in slot N12 followed by the playback of track N6 of a disc stored in slot N47 and followed by the playback of another track from a next disc. The sequence of operation begins with the application of an appropriate electric signal to the motor 18, which may be a stepper motor, to turn the plate 14 so that a playback unit 12 is aligned with the slot N12. (In the embodiment described, the playback units are rotated and the magazine is stationary. In an alternative embodiment, the playback units are stationary, reducing their potential vibration, and the magazine is rotated.) Upon achievement of that desired alignment, a motor 40 associated with the playback unit 12 and mounted on the plate 14 is actuated. The motor 40 engages a toothed rack 42 and drives it radially outward relative to the axis 15. The extended rack 42 engages complementary cogs 44 disposed on a circular end of the lever 9 proximate the pin 10. The extension and engagement of the rack 42 rotates the hook-like end of the lever 9 about the pin 10 toward the axis 15 of the magazine 3. The hook-like end of the lever 9 engages the selected disc and transfers it from the slot N12 into the playback unit 12. The motor 40 is then reversed, retracting the rack 42 toward the axis 15, so that the lever 9 returns to its rest position as shown in Figure 2. Preferably simultaneously, the playback unit 12 engages the selected disc, locates track N3 and begins the retrieval of the information recorded at that track. Next, the microprocessor sends an appropriate signal to the motor 18 to rotate the plate 14 (to turn the playback units or the magazine 3) to align the playback unit 13 with the slot N47 of the magazine 3. When that alignment has been achieved, while the disc in the first playback unit 12 continues its playback, the motor associated with the second playback unit 13 (not shown but corresponding to the motor 40 of the first playback unit 12) is actuated, causing the transfer of the selected disc from the slot N47 into the second playback unit 13. The second playback unit 13 cues the selected disc to the track N6 and then pauses. Meanwhile, the transfer lever in the slot N47 has been returned to its rest position. The microprocessor controls the acceleration and deceleration of the plate 14 where the playback units are rotated during the second slot alignment and disc transfer to avoid shock or vibration that might interfere with the simultaneous operation of the first playback unit 12. Upon completion of the playback of the track N3 from the first selected disc, the standby or pause status of the second selected disc is released and playback of that disc begins. Under control of the microprocessor, the plate 14 is then rotated again so that the first selected disc can be returned to the slot N12. After the alignment of the first playback unit 12 and the slot N12, the playback unit ejects the disc which rolls back into the slot N12 by gravitational force. When that transfer has been completed, the microprocessor proceeds to the next set of instructions which direct the first playback unit 12 to become aligned with the next slot corresponding to the disc which has been selected and from which information is to be retrieved. Thereafter, the process continues in the same manner. Alternatively, after transfer of the second selected disc to the second playback unit 13, the first playback unit 12 may be again aligned with the slot N12 At the conclusion of the information retrieval from the track N3 the first playback unit 12 ejects the first selected disc directly into the slot N12 without any delay because the first playback unit 12 is already into alignment with the slot N12. The second playback unit 13 is simultaneously released from its paused status and information retrieval from the second selected disc is begun. After return of the first disc to the slot N12 the first playback unit 12 is aligned with a next slot and the disc in that slot is transferred to the first playback unit 12. The alternative process continues thereafter in the same manner. Continual operation of the changer to retrieve record and playback selected portions of the record is accomplished according to the described or similar processes. Information is continuously retrieved from any of the discs in any desired sequence without any interrupting dead time between retrievals. By mounting the two playback units 12 and 13 within the central opening of the annular magazine 3, the dimensions of the changer do not have to exceed the outside dimension of the magazine 3. Further, by mounting the two playback units 12 and 13 in overlapping opposition, as shown in Figure 1, the dimension of the central opening 4 of the magazine 3 can be minimized. Alternatively, if space permits, the openings of the playback units 12 and 13 for receiving disc records can be diametrically opposed or can be radially disposed, forming an acute angle. As noted above, the playback units 12 and 13 can have the construction shown in U.S. Patents 4,498,162 and 4,546,396. In addition, the structure of another playback unit, similar to that disclosed in U.S. Patent 4,546,396 is shown in plan, top and rear views in Figures 4A, 4B and 4C. Figure 4A represents the unit with the pins 144, 145 fully spread, before the introduction of a disc. In all of those figures, the same elements are given the same reference numbers. The arrow A in Figure 4A indicates the direction of insertion of a disc in the playback unit. In this particular embodiment the levers work as follows : after a disc has been inserted in the unit 100 (Figure 4A), its edge are contacted by a first pair of pins 144, 145 that are mounted on pivoted biased levers 142, 143. These two complexly shaped levers 142 and 143 can respectively pivot near their respective centers 140, 141. The first lever 142 has a cruciform shape with four extending fingers. The second lever 143 has a paddle shape with one extending finger and a relatively large oppositely extending trapezoidal shaped portion. The levers 142 and 143 respectively have transverse fingers that extend away from the rear wall 106 and respectively include downwardly extending pins 144 and 145 that respectively slidably engage the arcuate slots 146 and 147 in the housing 130. The lever 142 is biased by resilient means , such as springs (not shown), to pivot about the pin 140 while the lever 143 because of its trapezoidal shaped portion always tend to be rotated anticlockwise by the gravity. Thus the pins 144 and 145 are urged inwardly, toward the side walls 104 and 102, respectively. The portions of the levers 142 and 143 disposed on the opposite side of the pins 140 and 141 from the pins 144 and 145 are thus urged outwardly, toward the side walls 102 and 104, respectively. These levers 142 and 143 are connected to slides 153, 152 respectively by the pins 150, 151 that engage the arcuate slots disposed in the housing 130 near the rear wall 106. Said slides 153, 152 bear pins 155, 154 respectively that engage the edge of an inserted disc. As it can be recognized this specific connection between the pairs of pins 144, 155 and 145, 154 corresponds to what is disclosed in the U.S. patent n o 4,498,162. The amount of spreading of those four pins 144, 145, 154, 155 indicates the diameter of the disc, a dimension that is employed in the final positioning of the disc for playback. Through the biasing of the levers 142, 143 those four pins 144, 145, 154, 155 act to center the disc in the unit. The centered disc is transported toward its playback position in the direction of arrow A of Figure 4A by a motor 128 and gears 120, 121 that translate the carriage driving the housing 130. As the centered disc approaches its playback position, a third pair of pins 156, 157, the separation of which is determined by the diameter of the disc, slidably engage oblique edges of openings 160A or 160B in a fixed rear wall 106. The sliding of those third pair of pins 156, 157 releases the engagement between the pins 144, 145, 154, 155 and the edge of the disc so that the disc is free to rotate for played back. Ejection of a disc consists of the same steps but taken in the opposite sequence. The pairs of pins 144, 155 ; 145, 154 engage the edge of the disc as it is removed from its playback means because the third set of pins 156, 157 slides, now in the opposite direction, along the oblique edges of the openings 160A, 160B in the rear wall 106. That engagement keeps the disc centered until the carriage is almost returned to its original insertion position. When that original position is almost reached, the engagement of the pins 162, 163 mounted on levers 142, 143 respectively, with the arms 164, 165 forces the lever to rotate and to release the disc which thus rolls back to its storage compartment in the magazine 3. When two sizes of disc are to be accommodated in a playback unit, two pairs of openings 160A, 160B are provided for engagement of the pins 156 and 157. In that case, the levers 142 and 143 will be spread to one of two possible spacings by each of the two disc sizes. A playback unit for a single disc size requires only one pair of openings for engaging the pins 156 and 157. More than two different sizes of discs can be accommodated by providing additional pairs of openings. While emphasis has been placed on a changer employed with disc records, such as compact discs, other types of records, including cassettes and even magnetic tapes, can be employed in the invention provided an appropriate transfer and cueing means is supplied. The changer embodiment described employs many common components, simplifying manufacture and reducing cost. The magazine includes identical, multiple walls and transfer lever assemblies. The playback units are preferably identical and can accommodate discs of various sizes. Thus, the novel changer is useful in a large number of applications because of its flexibility, its relatively small size, and its low cost.

Claims: A changer for sequentially retrieving recorded information on a selected record (7) while another previously selected record (7) is being cued or played back so that records (7) may be played back without any interruption, comprising a magazine (3) for storing a plurality of records (7) along a number of planes (30, 31) and at least partially surrounding an open space (4) a first record selection, loading, playback and unloading mechanism (12) mounted on a support (14) disposed in said open space (4) and providing relative movement between said magazine (3) and said mechanism (12) for selecting stored records (7) from said magazine (3), retrieving recorded information from selected records (7), and for returning selected records (7) to said magazine (3) respectively, characterized in that said support (14) bears a second record selection, loading, playback and unloading mechanism (13) similar to the first one (12) and mounted in such a way that the loading planes of said first and second record selection, loading, playback and unloading mechanisms (12, 13) are disposed side by side, parallel and in opposition to each others and, upon selection, aligned with each one of the number of planes (30, 31) where records (7) are stored, so that any stored record (7) can be selected from said magazine (3) to be loaded in any playback mechanisms (12, 13) whereby an imaginary circle (32) around the central axis (15) of the support (14) is disposed between and tangentially to the loading and unloading planes (30, 31) of the said two mechanisms (12, 13) and to the planes of the selected (30, 31) stored records (7). A changer according to claim 1, characterized in that said magazine (3) is annular and includes a central opening (4) in which is disposed the support (14) bearing said two record selection, loading, playback and unloading mechanisms (12, 13). A changer according to claim 1, characterized in that said magazine (3) comprises a plurality of walls (5) disposed generally tangentially relative to a circle of smaller radius than said imaginary circle (32), adjacent pairs of said adjacent walls (5) forming slots (6) therebetween for receiving records (7). A changer according to claim 1, characterized in that said first and second playback mechanisms (12, 13) are independent in operation from said second and first selection and return mechanisms, respectively, for sequentially retrieving information from different selected records (7) without interruption. A changer according to claim 2, characterized in that it includes an electric motor (18) for rotating said support (14) to align said first and second selection, loading, playback and unloading mechanisms (12, 13) with preselected positions in said magazine (3). A changer according to claim 1, characterized in that it includes a plurality of transfer levers (9) pivotally mounted in said magazine (3) for transferring record (7) from said magazine (3) to said first and second mechanisms (12, 13). A changer according to claim 6, characterized in that each of said first and second mechanisms (12, 13) includes a rack (42) driven by an electric motor (40) for engaging and pivoting a selected one of said levers (9) to transfer a selected record (7) from said magazine (3) to the respective mechanisms (12, 13). A changer according to claim 1, characterized in that the relative movement between said magazine (3) and the support (14) of both said mechanisms (12, 13) is controlled by a microprocessor which monitors the acceleration or deceleration of it in order to avoid any shock or vibration during playback of information.

Inventors: AGOSTINI, LOUIS PIERRE CESAR, Agostini, Louis Pierre César
Applicants: STAAR SOCIETE ANONYME
Application year: 1988
Main classification: G11B17
IPC codes: G11B17