A GEAR-WHEEL DRIVE FOR A CLEANING CASSETTE FOR USE IN CASSETTE TAPE RECORDERS

Abstract: A cleaning cassette for cassette tape recorders comprises a cleaning member which upon placing the cassette in the tape recorder is brought into engagement with its recording/reproducing head and which through a transmission device is connected with an effective coil drive shaft in the tape recorder so as to impart to the cleaning member by the rotation of the coil drive shaft a reciprocating sweeping movement across the sound head. The transmission device includes two mutually engaging driven gear-wheels (14, 16), one of which carries the eccentric head (8) which by means of a pivot arm (5) imparts to the cleaning member (1) the reciprocating cleaning movement. Said driven gear-wheels (14, 16) are arranged so as to be applicable in a one-way coupling connection with a first and a second pinion (12, 13), resp., individually mounted axially displaceable on a threaded hub means (10, 11) in engagement with a coil drive shaft, thereby allowing displacement between positions in wich the pinion (12, 13) is in engagement and out of engagement, resp., with the actual driven gear-wheel. Irrespective of which of the hub means (10, 11) is connected with the effective main drive shaft a correct cleaning function is obtained without establishing through the cleaning cassette any drive connection to the second hub means.

Description: A gear-wheel drive for a cleaning cassette for use in cassette tape recorders. The present invention relates to a cleaning cassette for cassette tape recorders comprising a cleaning member which upon placing the cassette in the tape recorder is brought into engagement with its recording/reproducing head and which is subjected to a reciprocating cleaning movement across the recording head by means of a pivot arm, one end of which is pivotal about a stationary axis while the other end is connected with the cleaning member, said pivot arm having a slot engaging an eccentric head connected through a transmission device with hub means for enga¬ gement with respective ones of the coil drive shafts of the tape recorder in such a manner that the cleaning member by rotation of an arbitrary one of the coil drive shafts of the tape recorder is subjected to said cleaning movement, the transmission device comprising two mutually engaging driven gear-wheels one of which carries the eccentric head. From DK patent No. 151,656 such a cleaning cassette is known in which the cleaning member is con¬ nected to both coil drives of the cassette by means of a gear-wheel arrangement including pinions communicat¬ ing with respective coil drives and engaging an idle wheel connected with an eccentric cam device actuating a pivot arm with which the cleaning member is con¬ nected. US patent No. 4 716 485 deals with a gear-wheel coupling with two driven gear-wheels, providing a rota¬ tional direction for the gear-wheel that is in engage- ment with the pivot arm, irrespective of which of the coil drive shafts is operable during the playing func¬ tion in a cassette tape recorder. The above designs provide for obtaining a correct cleaning function irrespective of the orien¬ tation of the cleaning cassette when positioned in the tape recorder, but the transmission devices suffer from the drawback that they establish a direct driving * con¬ nection from the first hub means to the second hub means of the cassette, thereby causing the motor of the tape recorder to perform, through the active coil drive shaft, not only the necessary motive power for the cleaning cassette but also a sufficient motive power for the indispensable co-rotation of the second coil drive shaft of the tape recorder and the transmission devices connected therewith. In a device disclosed in EP patent No. 0,144,364 this drawback has been eliminated in that the reciproc¬ ating movement of the cleaning member is provided by means of a spring-biassed pivot arm actuated by a cam device connected with one of the hub means, while a second pivot arm is positioned between a holder for the cleaning member and a cam device connected with the second hub means in such a manner that the second pivot arm which is not directly connected with the holder of the cleaning member by engagement between the second hub means and the effective coil drive shaft of the tape recorder may impart a forward movement to the cleaning member against the spring bias force exerted on the first pivot arm, while the return movement is solely effected by the spring bias force. Thereby a direct drive connection from the first to the second hub means of the cassette is avoided, but the design of the transmission device with two separate pivot arms in connection with the respective coil dri¬ ves and a spring bias force acting solely on one of the pivot arms involves a comparatively work consuming mounting and thus also increases the production price of the cleaning cassette. 3 DK patent application No. 3820/88 likewise deals with a cleaning cassette eliminating the co-rotation of the second coil drive shaft. This is obtained in that a first and a second pinion communicating with a respect- ive one of said hub means are connected directly or through an idle wheel, resp., with a respective one of two transfer gear-wheels independently rotatable about a common axis and which via a respective one-way coupling device with the same coupling direction are connected with the same shaft pin rotatable about the common axis and carrying the eccentric head. The mechanical mounting of this cassette is also comparatively work-consuming, because gear-wheels, one¬ way couplings and pivot arm being superposed on three levels. The object of the invention is to provide a cleaning cassette of the type concerned in which the functional advantage of the latter of the above men¬ tioned known designs is maintained concurrently with obtaining a simpler mounting and a more sturdy design of the transmission device, thereby further compens¬ ating more easily for productional tolerances. This is obtained according to the invention in that the driven gear-wheels are arranged so as to be used in a one-way coupling connection with a first and a second pinion, resp. , said one-way coupling being provided in that the pinions are individually mounted axially displaceable on a threaded hub means in engage¬ ment with a coil drive shaft, thereby allowing displa- cement between positions in which the pinion is in engagement and out of engagement, resp., with the actual driven gear-wheel. The invention will now be explained in more detail with reference to the accompanying schematical drawings, in which Fig. 1 is a plane view of a cleaning member with an associated transmission device in an embodiment of the cleaning cassette according to the invention, Fig. 2 is a sectional view along the lines II-II in Fig. 1, Fig. 3 is a threaded hub means according to the invention, Fig. 4 is a plane view of a pinion in Fig. 2, and Fig. 5 is a sectional view of the pinion along the line V-V in Fig. 4. In the illustrated embodiment a cleaning member 1 is mounted in a holder 2 which in a manner not shown, e.g. by guide tracks in the cassette walls is controlled to effect reciprocating movement in the cleaning cassette in the direction shown by arrows 3. This movement causes the cleaning member, e.g. formed as a felt pad moistened with cleaning liquid, to effect a sweeping movement across the recording/reproducing head not shown of the tape recorder and on which the cleaning member is kept abutting by a pressure spring 4. Holder 2 is connected with the free end of a pivot arm, 5 the opposite end of which is pivotally journalled on a pivot pin 6 secured on the cassette. The pivot arm 5 is provided with a slot 7 engaging an eccentric head 8 supported on a driven gear-wheel 14 that is in firm engagement with the second driven gear-wheel 16. For the purpose of engagement with the coil drive shafts, not shown, of the tape recorder the cassette is provided with two hub means 10 and 11 corresponding to the coil drive shafts in a general tape cassette. Each of the hub means 10 and 11 is provided with an external thread for engagement with pins located internally of the pinions 12 and 13 for axial displacement thereof on hub means 10 and 11, between positions in which pinions 12 and 13 engage or disengage, resp. , the driven gear-wheels 14 and 16. When a hub means 10 or 11 upon placing the cassette in the tape recorder is made to communicate with the effective coil drive shaft thereof, the rota¬ tion of hub means 10 or 11 in the usual direction of rotation, shown by arrow 18 or 19, will displace pinion 12 or 13 axially to engage the driven gear¬ wheel 14 or 16, thereby also making eccentric head 8 to rotate so that pivot arm 5 is made to effect a reciprocating pivoting movement about pivot pin 6, thereby actuating cleaning member holder 2 to perform the reciprocating sweeping movement illustrated by arrows 3. The other hub means 11 or 10 is con¬ nected to the non-effective coil drive shaft of the tape recorder in such a manner that hub means 11 or 10 stands still. As the corresponding pinion 13 or 12 by the driven gear-wheel 15 or 14 is rotated in the direction of arrow 19 or 18, said pinion 12 or 13 is displaced axially out of engagement with the associated driven gear wheel 16 or 14 until it gets stopped by abutting on the cassette wall or, in the illustrated embodiment, on cam 20 protruding down¬ wards therefrom. This provides for obtaining that solely the hub means which is in engagement with an effective coil drive shaft in the tape recorder is made to rotate without causing any co-rotation of the hub means that is not connected to an effective coil drive shaft. In fact, no driving connection is established between the hub means through the cleaning cassette.

Claims: 6 P A T E N T C L A I M S 1. A cleaning cassette for cassette tape recor- ders comprising a cleaning member (1) which upon placing the cassette in the tape recorder is brought into engagement with its recording/reproducing head and which is subjected to a reciprocating cleaning movement across the recording head by means of a pivot arm (5) one end of which is pivotal about a stationary axis (6) while the other end is connected with the cleaning member (1), said pivot arm (5) having a slot (7) engaging an eccentric head (8) connected through a transmission device with hub means (10, 11) for engage¬ ment with respective ones of the coil drive shafts of the tape recorder in such a manner that the cleaning member (1) by rotation of an arbitrary one of the coil drive shafts of the tape recorder is subjected to said cleaning movement, the transmision device including two mutually engaging driven gear-wheels (14, 16) one of which carries the eccentric head (8), characterized in that the driven gear-wheels (14, 16) are arranged so as to be used in a one-way coupling connection with a first and a second pinion (12, 13), resp., said one-way coupling being provided in that the pinions (12, 13) are individually mounted axially displaceable on a threaded hub means (10, 11) in engagement with a coil drive shaft, thereby allowing displacement between positions in which the pinion (12, 13) is in engagement and out of engagement, resp., with the actual driven gear-wheel (14, 16) .

Inventors: MOELLER HELGE, MOESGAARD ANDERS, MOELLER, HELGE, MOESGAARD, ANDERS
Applicants: AM KEMI AS, AM KEMI A/S
Application year: 1990
Main classification: G11B5
IPC codes: G11B5, G11B23