Tape loading mechanism

Abstract: A tape loading mechanism for withdrawing a magnetic tape (71) from a tape cassette (7) includes a pair of rails (3, 31), each formed in a plane, for guiding the movement of a pair of tape guide assemblies (5, 51), respectively. At least one of the rails is inclined with respect to a cylinder base (1). The tape guide assembly on the inclined rail (3) is positioned at a lower level than the tape in the cassette when the tape is to be loaded, is brought to the same level as the tape during loading and engages the tape at this level to further withdraw the tape from the cassette.

Description: The present invention relates to magnetic recording-reproduction apparatus such as 8-mm VTRs and digital audio tape recorders, and more particularly to a tape loading mechanism for withdrawing magnetic tape from a tape cassette. With reference to Figs. 1B and 17, common VTRs include a head cylinder 2 inclined at a specified angle and mounted on a cylinder base 1, and a pair of circular-arc rails 30a, 30b arranged around the head cylinder 2. Tape guide assemblies 50a, 50b are slidably mounted on the rails 30a, 30b, respectively. The guide assemblies 50a, 50b are moved along the respective rails to thereby withdraw magnetic tape 71 from a tape cassette 7 and wind the tape around the head cylinder 2 over a predetermined angle about the center thereof. As shown in Fig. 24, the tape guide assembly 50a comprises guides 53, 54 provided on the upper side of a slide base 52 for withdrawing the tape, a rod 58 projecting from the lower side of the base 52 and extending through a guide slit 32 of the rail 30a, and a pair of slide pieces 101, 101 provided on the respective opposite sides of the slide base 52. Pulling drive means comprising a loading ring, etc. is connected to the lower end of the rod 58 by a connector as will be described later to exert on the guide assembly 50a a pulling force acting longitudinally of the guide slit 32 of the rail. Usually, one of the pair of rails, 30b, is formed along a plane and disposed approximately horizontally above the cylinder base 1, whereas the other rail 30a is curved to include a bent portion R and inclined with respect to the cylinder base 1 (see, for example, Unexamined Japanese Patent Publications SHO 60-87458, SHO 59-171070 and SHO 60-35364). Accordingly, the guide assembly 50a on the curved rail 30a is held at the same level as the cassette 7 as indicated in solid line before starting to load the tape, gradually rises as it advances with a loading operation, and reaches a predetermined level as indicated in broken line on completion of the loading operation. At the higher level, the assembly 50a is held as inclined. As seen in Fig. 17, consequently the magnetic tape 71 withdrawn from the cassette 7 is wound at a predetermined angle of inclination around the head cylinder 2. With reference to Fig. 24, the guide assembly 50a at the end of path of its movement is positioned by the contact of the pair of slide pieces 101, 101 at opposite sides of the slide base 52 with the rail 30a with respect to the direction of Z axis shown (axial direction of the rod 58), and also by the contact of the rod 58 projecting downward from the slide base with the slit (32) defining side wall of the rail 30a with respect to the direction of X axis (perpendicular to the Z axis). Further with the conventional VTR, the path of travel of the tape from a supply reel 72 to the head cylinder 2 when the tape is completely loaded as seen in Fig. 17 is provided by a tape drawing guide 63, first to third tape guides 9, 91, 92 and the pair of guides 53, 54, and all of these tape guides 63, 91, 92, 53, 54 other than the first tape guide 9 are mounted on a pivotal arm (not shown) operatively related to the loading movement. These movable guides advance with the loading movement and withdraw the magnetic tape 71 in sliding contact with the nonmagnetic side of the tape 71 to form the specified tape travel path. With the conventional VTR wherein the supply rail 30a is curved and includes the bent portion R, the tape supply guide assembly 50a must have some play relative to the rail 30a. Consequently, the play causes a backlash. Especially with compact 8-mm VTRs wherein the rail 30a is spaced from the head cylinder 2 by a small distance, the guide assembly 50a is likely to come into contact with the head cylinder 2 during tape loading. To preclude the backlash, the portion where the guide assembly 50a is in engagement with the rail 30a requires complex means for absorbing the play. Further in the arrangement of Fig. 24 for positioning the guide assembly 50a in place, the assembly is positioned with respect to the direction of X axis by the line ccntact between the periphery of the rod 58 and the guide slit (32) defining side wall of the rail 30a, so that owing to variations in the accuracy with which the guide slit 32 is machined, the rod 58 is likely to contact the upper edge of the slit defining wall or the lower edge thereof. This results in variations in the accuracy with which the guide assembly is positionable, making it difficult to position the assembly properly. The conventional VTR has another problem in that the loading mechanism is very complex because the multiplicity of tape guides 63, 91, 92, 53, 54 need to be arranged movably as seen in Fig. 17 to provide the travel path for the tape as completely loaded and further because a link assembly is necessary for driving these guides forward and rearward. These problems impose limitations on attempts to provide lightweight and compacted loading mechanisms for 8-mm VTRs. GB-A 2 149 958 discloses a tape loading mechanism according to the preamble of claim 1, wherein each of the guide assemblies are moveable on a pair of rails extending in a plane parallel to the cylinder base. An object of the present invention is to prevent the backlash involved in the movement of the tape guide assembly by a simple construction so as to provide a tape loading mechanism having a simple construction. Another object of the invention is to provide a tape loading mechanism wherein the tape guide assembly can be positioned accurately at the end of its movement. Another object of the invention is to provide the desired path of travel of tape by a minimized number of movable tape guides and to thereby provide a tape loading mechanism of simple construction. These objects are achieved by a tape loading mechanism as defined in claim 1; the dependent claims relate to further developments of the invention. With the tape loading mechanism of the present invention, a pair of rails are formed each in a plane, and at least one of the rails is inclined with respect to a cylinder base. A tape guide assembly on the inclined rail is positioned at a lower level toward the cylinder base than the level of the magnetic tape in a tape cassette when the tape is to be loaded, is brought to the same level as the tape in the course of loading operation and comes into contact with the tape at this level. The guide assembly thereafter further withdraws the tape from the cassette and winds the tape around a head cylinder. The side wall of the rail which defines a guide slit formed therein and with which a rod on the tape guide assembly comes into contact is formed with a contact portion having an edged section and serving as stopper means for limiting the movement of the tape guide assembly. Further with the tape loading mechanism of the invention, three fixed tape guides for the magnetic side of the magnetic tape to come into contact with provide a path of travel of the tape between the tape guide assembly on the inclined rail and the tape cassette. The tape guide assembly on the inclined rail moves on a plane for a loading operation, performing a first movement wherein the assembly advances without contacting the magnetic tape of the cassette and a second movement wherein the assembly comes into contact with the tape to further withdraw the tape from the cassette and wind the tape around the head cylinder. During the first movement, the tape in the cassette is withdrawn from the cassette, for example, by tape drawing guides movable with the loading operation. The tape is thereafter wound around the head cylinder by the second movement of the tape guide assembly. With respect to a direction perpendicular to the longitudinal direction of the rail, the tape guide assembly is positioned in place at the end of its movement by the point contact of the rod projecting from the guide assembly with the contact portion formed in the guide slit defining side wall of the rail. The magnetic tape withdrawn from the cassette, for example, by the tape drawing guides comes into contact with the three fixed tape guides during the loading operation, and these fixed tape guides define the path of travel of the tape after the tape is completely loaded. The magnetic tape can be changed in its course as specified by the tape guide in an intermediate position included in these three tape guides, and the other two tape guides regulate the angle at which the tape is wound around the tape guide in the intermediate position. With the tape loading mechanism of the present invention, the two rails for guiding the movement of a pair of tape guide assemblies are each formed in a plane, so that each tape guide assembly is reciprocatingly movable in a stabilized posture without the necessity of giving the undesired play to the tape guide assembly in engagement with the rail. Consequently, there is no need to provide any special means for preventing the tape guide assembly from backlashing. This serves to simplify the tape loading mechanism. With respect to a direction perpendicular to the longitudinal direction of the rail, the tape guide assembly is positionable in place at the end of its movement by the point contact of the rod with the rail as already described. This assures accurate positioning at all times. The change in the course of the magnetic tape required for forming the predetermined path of its travel can be accomplished by the three fixed tape guides which are disposed outside the path, so that the movable tape guides to be disposed inside the travel path can be smaller in number than is conventionally needed. This serves to simplify the tape loading mechanism. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A is a side elevation showing a feature of the tape loading mechanism of the invention; Fig. 1B is a side elevation corresponding to Fig. 1A and showing a conventional tape loading mechanism; Fig. 2 is an exploded perspective view showing a head cylinder and the tape loading mechanism of the invention; Fig. 3 is a perspective view of the mechanism on completion of a loading operation; Fig. 4 is a perspective view of the same on completion of an unloading operation; Figs. 5 to 9 show the tape loading mechanism in sequential operation from the start of loading until completion of loading; Fig. 5 is a plan view of the same when starting loading; Fig. 6 is a plan view of the same while a first tape guide assembly is in a first movement; Fig. 7 is a plan view of the same upon tape drawing guides completing withdrawing the tape; Fig. 8 is a plan view of the same while the tape guide assembly is in a second movement; Fig. 9 is a plan view of the same on completion of the loading operation; Fig. 10 is a front view showing the tape guide assembly as positioned at a level when starting the loading operation; Fig. 11 is a front view showing the tape guide assemlby as positioned at a level immediately before completion of the first movement; Fig. 12 is a side elevation showing a connector between the tape guide assembly and a loading ring on completion of the loading operation; Fig. 13 is a side elevation showing the same on completion of unloading; Fig. 14 is a fragmentary plan view of an arm constituting the connector; Fig. 15 is a perspective view showing pivot connection means; Fig. 16 is a plan view showing the path of travel of the tape in the loading mechanism of the invention; Fig. 17 is a plan view showing the path of travel of the tape in the conventional loading mechanism; Fig. 18 is a perspective view showing the tape guide assembly in engagement with a stopper on a supply rail according to the invention; Fig. 19 is a plan view of the same; Fig. 20 is a side elevation partly broken away and showing the same; Fig. 21 is a front view partly broken away and showing the same; Fig. 22 is a plan view of the supply rail; Fig. 23A is a view in section taken along the line a-a in Fig. 22; Fig. 23B is a view in section taken along the line b-b in Fig. 22; Fig. 24 is a front view partly broken away and showing a conventional tape guide assembly in engagement with a rail. DETAILED DESCRIPTION OF EMBODIMENT With reference to the drawings, a tape loading mechanism will be described in detail which embodies the invention for use in an 8-mm VTR. Referring to Fig. 1A, the tape loading mechanism of the invention is characterized in that a supply rail 3 is formed in a plane and inclined with respect to a cylinder base 1. A tape guide assembly 5 on the inclined rail 3 is positioned at a lower level toward the cylinder base 1 than magnetic tape 71 accommodated in a tape cassette 7 when the tape is to be loaded, and is brought to the same level as the tape 71 during loading. At the latter level, the tape guide assembly 5 comes into contact with the tape 71, further withdraws the tape from the cassette 7 and winds the tape around head cylinder 2. With reference to Fig. 2, a cylinder support 15 is disposed at the center of the cylinder base 1, and the head cylinder 2 is mounted as inclined at a predetermined angle on the support 15. Arranged around the cylinder support 15 are ring drive rollers 16, 16, 16 for drivingly rotating a pair of loading rings 4, 41 in directions opposite to each other as already known. Provided on the cylinder base 1 are three fixed tape guides for providing a specified path of travel of the tape when the tape has been completely loaded, i.e., first tape guide 6, second tape guide 61 and third tape guide 62 on the supply side. Also arranged on the base 1 are a take-up tape guide 8, and a capstan 81 for forwarding the tape. The second tape guide 61 on the supply side serves to change the course of the tape 71 as specified on completion of loading. The first and third tape guides 6, 62 regulate the angle at which the tape 71 is wound around the second tape guide 61. The tape guide assembly 5 comprises leading guides 53, 54 which are inclined at the same angle as the third tape guide 62 Further provided on the cylinder base 1 are a pair of supply-side support pieces 11, 12 for supporting the supply rail 3 as inclined at a predetermined angle, and a pair of take-up side support pieces 13, 14 for supporting a take-up rail 31 horizontally. The supply rail 3 and the take-up rail 31 each extend in a circular-arc form in a plane and are formed with guide slits 32, 33, respectively, along their length. The rails 3, 31 are integrally formed each at its innermost end with stoppers 34, 35, respectively, as by die casting for limiting the movement of the guide assemby 5 and a tape guide assembly 51. With reference to Figs. 18 to 22, the stopper 34 of the supply rail 3 comprises a plurality of contact portions including a gate-shaped contact member 34a for the forward end 100 of a slide base 52 of the tape guide assembly 5 to advance therethrough, a contact portion 32a of the side wall of the rail 3 defining the guide slit 32 for a first rod 58 projecting downward from the bottom of the slide base 52 to come into contact with, and the terminal end 32b of the rail 3 for a second rod 59 projecting downward from the bottom of the base 52 to come into contact with. As seen in Fig. 2, the rails 3, 31 are formed on their outer edges with boss portions 36a, 36b and 38a, 38b, respectively, which are fastened to the supply-side support pieces 11, 12 and the take-up side support pieces 14, 13 with screws. The boss portion 36a of the rail 3 is positioned approximately at the midportion of the rail, and the other boss portion 36b thereof is adjacent to the stopper 34. The rail portion beyond the boss portion 36a toward the rail outer end is supported above the cylinder base 1 in a cantilever fashion. Immediately adjacent to the boss portion 36a toward the outer or free end, the rail has an arcuate cutout 37. Accordingly, even if the support rail 3 is subjected to a bending external force as by the tape guide assembly 5 upon the start of loading, the force will be absorbed by the elastic deformation of the rail portion of reduced width where the cutout 37 is formed. Consequently, the stopper 34 can be maintained in position accurately. This structure is usable also for the take-up rail 31. The supply-side tape guide assembly 5 has its slide base 52 slidably fitted in the guide slit 32 of the rail 3, and the first and second leading guides 53, 54 are provided on the base 52. Similarly, the take-up tape guide assembly 51 comprises a slide base 55 slidably fitted in the guide slit 33 of the rail 31, and first and second leading guides 56, 57 projecting upward from the base 55. The guide assemblies 5, 51 are connected to the loading rings 4, 41 by connectors 42, 43, respectively. The supply rail 3 is connected to the loading ring 4 by the structure shown in Figs. 12 to 15. The connector 42 comprises first and second arms 44, 45 in engagement with each other stretchably axially thereof, and a spring 46 is provided between the two arms. The arms 44, 45 are provided at their outer ends with arcuate bent portions 44a, 45a each having a slot 49 extending longitudinally of the arm as seen in Fig. 14. The rail 3 and the loading ring 4 have semispherical pivot support pieces 48, 47, respectively, attached thereto by a slender stem (indicated at 47a in Fig. 15) fitted in each slot 49. Accordingly the bent portions 44a, 45a of the arms 44, 45 are movable relative to the support pieces 48, 47 in the direction of rotation of arrow A and in the direction of arrow B shown in Fig. 15, whereby pivot connection means are provided. With the arrangement of Fig. 12, the slide base 52 comes into contact with the stopper 34 on completion of loading, and the loading ring 4 further slidingly moves rightward in Fig. 12, pulling the arm 45 in the direction of arrow E1. This compresses the spring 46, forcing the two arms 44, 45 toward each other and thereby bringing the tape guide assembly slide base 52 into pressing contact with the stopper 34 to accurately determine the position and posture of the guide assemblies 53, 54. On completion of unloading, the loading ring 4 comes into contact with the end of the supply rail 3 at the extemity of the guide slit 32, and the ring 4 further slidingly moves leftward in Fig. 13 to force the arm 45 in the direction of arrow E2. This stretches the spring 46, biasing the two arms 44, 45 away from each other with a force weaker than that acting on completion of loading, whereby the slide base 52 is pressed against the end of the rail 3 defining the extremity of the guide slit to determine the position of the guide assembly 5. The take-up tape guide assembly 51 is also connected to the loading ring 41 by the same structure as above. In the tape loading operation, the loading ring 4 for driving the supply-side guide assembly 5 rotates clockwise, while the loading ring 41 for driving the take-up guide assembly 51 rotates counterclockwise. Consequently, the two guide assemblies 5, 51 advance along the respective rails 3, 31 from the position of Fig. 4 to the position of Fig. 3. During this movement, the leading guides 53, 54 of the guide assembly 5 move obliquely upward along the supply rail 3 as held inclined at an angle of 15 degrees with the Z axis shown and about 21 degrees with the X axis. On the other hand, the leading guides 56, 57 of the take-up guide assembly 51 move along the rail 31 while remaining at the same level. Figs. 18 to 23 show the structure of the stopper 34 on the supply rail 3 and the tape guide assembly 5 as engaged with the stopper. With reference to Fig. 22, the rail 3 has formed in its guide slit 32 close to its terminal end 32b the side wall contact portion 32a for the first rod 58 to bear against. As seen in Figs. 23A and 23B, the slit 32 has an upwardly tapered cross section over the entire length thereof. As shown in Figs. 18 to 21, the slide base 52 of the guide assembly 5 is formed on the upper face of its forward end 100 with a first protuberance 52a adapted to come into contact with the top wall of the gate-shaped contact member 34a. The slide base 52 also has on its lower face second and third protuberances 52b, 52c in sliding contact with the upper face of the rail 3 at opposite sides of the guide slit 32. The first and second rods 58, 59 projecting from the lower face of the slide base 52 are arranged along the direction of its movement, with the connector 42 attached to the first rod 58. When the tape guide assembly 5 reaches the end of path of its movement upon completion of tape loading, the first rod 58 bears against the edge of the side wall contact portion 32a formed in the vicinity of the terminal end of the guide slit 32, with the second rod 59 bearing against the terminal end 32b of the rail 3 at the extremity of the guide slit 32. In this state, the tape guide assembly 5 is in balance with the following moments of forces. With reference to Figs. 18 to 21, the Y axis is an axis of coordinate intersecting the axes of the first and second rods 58, 59 of the guide assembly 5 at right angles therewith, the Z axis is a coordinate axis in coincidence with the axis of the first rod 58, and the X axis is a coordinate axis perpendicular to both the Y and Z axes. Suppose the pulling drive force acting on the connector 42 is F, a component of the force F in the X-Y plane (Fig. 19) is Fxy, a component thereof in the Y-Z plane (Fig. 20) is Fyz, and a component thereof in the X-Z plane (Fig. 21) is Fxz. The moment acting on the guide assembly due to the component Fxy is in balance with the reaction exerted by the side wall contact portion 32a of the rail 3 on the first rod 58 and acting about the second rod 59 as seen in Fig. 19. The moment due to the component Fyz is in balance with the reaction exerted by the rail upper face on the second and third protuberances 52b, 52c and acting about the first protuberance 52a of the assembly 5 as seen in Fig. 20. The moment due to the component Fxz is in balance with the reaction exerted by the rail upper face mainly on the third protuberance 52c and acting about the point of contact, 3a, between the first rod 58 of the assembly 5 and the side wall contact portion 32a of the rail 3 as shown in Fig. 21. Consequently, the tape guide assembly 5 is held pressed in position. The stopper described is of course usable also for the tape guide assembly 51 on the take-up rail 31. The operation of the tape loading mechanism will be described below with reference to Figs. 5 to 9. The VTR incorporating the present embodiment is of the type wherein the tape cassette 7 is drivingly advanced toward the head cylinder 2 during the period from the start of loading until the completion of loading (see, for example, Unexamined Japanese Patent Publication SHO 61-271648). Accordingly, the distance L1 between the front end of the cylinder base 1 and the front end of the tape cassette 7 when the loading operation is to be started as seen in Fig. 5 gradually decreases to L2 in Fig. 6, then L3 in Fig. 7, further L4 in Fig. 8 and finally to the state of completion of loading shown in Fig. 9. When the mechanism is to start loading as seen in Fig. 5, tape drawing guides 63, 83, the supply-side guide assembly 5, the take-up side guide assembly 51 and a pinch roller 82 are accommodated in the opening of the tape cassette 7. At this time, the take-up side guide assembly 51 is at the same level as the magnetic tape 71 as shown in Fig. 10, whereas the supply-side guide assembly 5 is at a lower level than the tape 71. In this state, the loading motor (not shown) is started, whereupon the guide assemblies 5 and 51 start advancing as seen in Fig. 6. Approximately at the same time, both the tape drawing guides 63, 83 start to withdraw the tape 71. At this time, the take-up guide assembly 51 is in contact with the tape 71, whereas the supply-side guide assembly 5 is away from the tape 71. When the loading operation advances, the tape drawing guides 63, 83 completely withdraw the tape as shown in Fig. 7. The guide assembly 51 further advances to wind the tape 71 around the head cylinder 2, whereas the guide assembly 5, still remaining away from the tape 71, rises as it advances along the supply rail 3, with the first and second leading guides 53, 54 brought approximately to the same level as the tape 71 as seen in Fig. 11. Accordingly, when the guide assembly 5 comes into contact with the tape 71 immediately thereafter, the flanges at the heads of the leading guides 53, 54 will not contact the tape 71 to render the tape 71 free of damage. Fig. 8 shows the supply tape guide assembly 5 and the take-up tape guide assembly 51 as further advanced. The magnetic tape 71 is in contact with the first tape guide 6, second tape guide 61, third tape guide 62 and guide assembly 5 on the supply side, and with the take-up tape guide 8 and capstan 81. During the process from Fig. 7 to Fig. 8, the tape 71 is first passed around the first to third tape guides 6, 61, 62 and is thereby changed in course generally toward the direction in which it is traveled when completely loaded, whereupon the guide assembly 5 comes into contact with the tape 71. Accordingly, it is unlikely that the tape 71 will be twisted or otherwise deformed by being handled by the assembly 5 for loading. Further in the state shown in Fig. 8, the pinch roller 82 is still out of contact with the tape and therefore offers no undesirable resistance to the tape withdrawing action. When the tape has been completely loaded as seen in Fig. 9, the guide assemblies 5 and 51 are at the terminal ends of the supply rail 3 and the take-up rail 31, respectively, and held in the specified posture as already stated. The pinch roller 82 holds the tape 71 in pressing contact with the capstan 81. Consequently, the path of travel of the tape 71 is established, and the tape is wound around the head cylinder 2 at a predetermined lead angle and winding angle. The tape 71 is unloaded through a process reverse to the above. With the tape loading mechanism described above, the rails 3, 31 are each formed in a plane, and the tape guide assemblies 5, 51 each move along on the plane. This eliminates the need for the undesirable play of the the assemblies 5, 51 conventionally required, thereby precluding the assemblies from backlashing. Furthermore, the travel path for the tape as completely loaded is provided by the three fixed tape guides 6, 61, 62 in sliding contact with the magnetic side of the tape 71 as seen in Fig. 16, with the result that the VTR described is smaller in the number of movable tape guides than conventional ones (e.g., one disclosed in Unexamined Japanese Patent Publication SHO 60-74143). This serves not only to provide the tape travel path with higher accuracy than heretofore possible but also to simplify the tape loading mechanism. The structures for connecting the tape guide assemblies 5, 51 to the respective loading rings 4, 41 comprise the pivot connection means shown in Figs. 12 to 15 and adapted for rotation and pivotal movement, so that the tape guide assemblies 5, 51 are freely movable. Furthermore, the elastically stretchable connectors 42, 43 included render the assemblies 5, 51 accurately positionable at the end of their movement. The supply rail 3 supported in a cantilever fashion and formed with the cutout 37 for absorbing external forces effectively obviates the likelihood that the stopper 34 for defining the position of the tape guide assembly 5 on completion of loading will be deformed by an external force. The tape guide assembly positioning arrangement shown in Figs. 18 to 21 does not include the right slide piece 101 of the conventional arrangement shown in Fig. 24 but instead has the second protuberance 52b in the vincinity of the first rod 58. The second protuberance 52b primarily functions to realize a balance between the moments shown in Fig. 20 but is irrelevant to the balance between the moments of Fig. 21, so that the second protuberance 52b can be positioned close to the first rod 58 to the greatest possible extent to make the slide base 52 smaller in width than heretofore possible. This makes it possible to install the rail 3 in close proximity to the head cylinder and to thereby provide a compacted tape loading mechanism.

Claims: A tape loading mechanism including a head cylinder (2) mounted as inclined at a predetermined angle on a cylinder base (1), a pair of rails (3, 31) arranged around the head cylinder (2) and a pair of tape guide assemblies (5, 51) movable as guided along the respective rails for winding a magnetic tape around the head cylinder (2) while withdrawing the tape from a tape cassette, each of the pair of rails (3, 31) extending in a plane from a starting end thereof closer to the cassette to a terminal end thereof close to the head cylinder (2), the tape loading mechanism being characterized in that at least one of the rails (3) being inclined with respect to the cylinder base (1) and having its starting end positioned close to the cylinder base (1) at a lower level than the tape within the cassette so as to maintain the tape guide assembly (5) at a lower level than the tape within the tape cassette when the tape loading is started, the inclined rail (3) having its terminal end positioned away from the cylinder base (1) so as to hold the tape guide assembly (5) on the inclined rail (3) at a higher level than the tape within the cassette on completion of loading, the tape guide assembly (5) on the inclined rail (3) being movable into contact with the tape while moving on the inclined rail (3) to withdraw the tape from the cassette. A tape loading mechanism as defined in claim 1 wherein one of the pair of rails (3) disposed toward one of the reels of the cassette is inclined with respect to the cylinder base (1), and the other rail (31) disposed toward the other reel is in parallel to the cylinder base (1). A tape loading mechanism as defined in claim 1 wherein a tape drawing guide (63) is provided on the cylinder base (1) and is movable with the tape loading operation away from the cassette, the tape drawing guide (63) being operable to withdraw the tape from the cassette first by contact with the tape, and the tape guide assembly (5) on the inclined rail (3) subsequently reaches the same level as the tape within the cassette from the end position of its movement close to the cassette and thereafter comes into contact with the tape. A tape loading mechanism as defined in claim 1 wherein a stopper (34, 35) is provided at the end of each rail remotest from the cassette for defining an end position of movement of the tape guide assembly (5, 51) on the rail (3, 31), and at least one of the rails (3) has boss portions (36a, 36b) disposed in the vicinity of the stopper (34) and fastened to the cylinder base (1) and is supported in the manner of a cantilever, the rail portion immediately adjacent to one of the boss portions (36a) at the cassette side thereof being formed with a cutout (37). A tape loading mechanism as defined in claim 1 wherein a stopper (34, 35) is provided at the end of each rail (3, 31) remotest from the cassette for defining an end position of movement of the tape guide assembly (5, 51) on the rail (3, 31) and at least one of the tape guide assemblies (5) has a slide base (52) slidable on the rail (2) and a rod (58) projecting from the slide base (52) and extending through a guide slit (32) formed in the rail (3), the stopper (34) defining the end position of movement of the tape guide assembly (5) having a plurality of contact portions including a contact portion (32a) on the slit (32) defining side wall of the rail (3) for the rod (58) to come into contact with, the side wall contact portion (32a) being edged in section perpendicular to the longitudinal direction of the guide slit (32) for point contact with the rod (58). A tape loading mechanism as defined in claim 1 wherein the pair of tape guide assemblies (5, 51) are connected to a pair of loading rings (4, 41), respectively, each by a connector (42, 43). A tape loading mechanism as defined in claim 6 wherein the connector (42, 43) comprises first and second arms (44, 45) in engagement with each other and movable away or toward each other axially thereof, and a spring (46) provided between the two arms (44, 45) for biasing the tape guide assembly (5, 51) and holding the assembly (5, 51) in opposite end positions of its movement on the rail (3, 31) on completion of loading and on completion of unloading. A tape loading mechanism as defined in claim 6 wherein the respective ends of the connector (42, 43) are connected to the rail (3, 31) and the loading ring (4, 41) by pivot connection means. A tape loading mechanism as defined in claim 1 wherein three fixed tape guides (6, 61, 62) adapted for contact with the magnetic side of the tape are arranged on the cylinder base (1) along a path of travel of the tape between the tape cassette and the tape guide assembly (5) mounted on the inclined rail (3) and positioned at the end of its movement remotest from the cassette, the tape being changeable in its course by the second fixed tape guide (61) positioned between the two other fixed tape guides (6, 62), the first and third fixed tape guides (6, 62) on opposite sides of the second tape guide (61) being operable to determine the angle at which the tape is wound on the second tape guide (61). A tape loading mechanism as defined in claim 1 wherein the pair of tape guide assemblies (5, 51) mounted on the respective rails (3, 31) being each slidably engaged in a guide slit (32, 33) formed in the rail (3, 31) and extending longitudinally thereof, stopper means being provided at the terminal end of each of the rails (3, 31) toward the head cylinder (2) for defining an end position of movement of the guide assembly (5, 51), pulling drive means being connected to each of the tape guide assemblies (5, 51) by a connector (42, 43), at least one of the tape guide assemblies (5) having a slide base (52) slidable on the rail (3) and a rod (58) projecting from the slide base (52) and extending through the guide slit (32) formed in the rail (3), the connector (42) being connected to the rod (58), the stopper means defining the end position of movement of the tape guide assembly (5) upon completion of tape loading and having a plurality of contact portions including a contact portion (32a) on the slit (32) defining side wall of the rail (3) for the rod (58) to come into contact with, the side wall contact portion (32a) being edged in section perpendicular to the longitudinal direction of the guide slit (32) for point contact with the rod (58).

Inventors: KODAMA YOSHIMI, OHNISHI YOSHIHISA, KODAMA, YOSHIMI, OHNISHI, YOSHIHISA
Applicants: SANYO ELECTRIC CO, SANYO ELECTRIC CO., LTD.
Application year: 1989
Main classification: G11B15
IPC codes: G11B15