Gear drive carriage and stepper adjustment system

Abstract: Apparatus for orienting a magnetic tape head in a tape drive assembly adapted to receive a magnetic tape with tracks thereon, the apparatus comprises a frame having plate support means, and a shaft member having an axis and mounted for rotation about its axis on the plate support means. The shaft member has a first end pivotably mounted on the plate support means, and a second end mounted on the plate support means and movable relative thereto, such movement causing pivoting of the shaft member at its first end. No apparatus includes a motor for rotating the shaft member about its axis, and a head carriage assembly including magnetic tape head mounted on the shaft member, the head being positioned in the tape drive assembly such that the head lies adjacent magnetic tape adapted to be received in the tape drive assembly. The head carriage assembly being movable over the shaft member in response to rotation whereby the head moves linearly in a direction substantially normal to movement of the tape to permit the head to locate and align with the tracks on the tape. An adjuster member is provided, having a securing portion adapted to be moved with respect to and secured to the plate support, and a connecting portion adapted to engage and move the second end of the shaft member. Movement of the securing portion adjusts the orientation of the shaft member and head carriage assembly, and the securing portion is firmly secured to the plate support when the head is in a desired orientation. The invention also comprises apparatus for precise positioning of a tape head at a track on magnetic tape adapted to be received in a drive assembly having a memory and a motor, the apparatus comprising a laser source for emitting a laser beam, a mounting tray for the tape drive assembly, a reflector member for mounting on the tape head for movement therewith, and means for directing the laser beam from the laser source to the reflector. Means associated with the laser source for accurately measuring the distance travelled by the tape head from a predetermined point to a position adjacent a track on the magnetic tape are provided. Further, the invention includes means for determining the extent of movement of the motor for the distance travelled by the tape head, and programming means for programming the tape drive assembly memory with the extent of such movement.

Description: Background of the Invention This invention relates to a method and apparatus for the positioning and setting of a magnetic head in a tape drive assembly for accurate tracking of magnetic tape contained in a cassette, the cassette being adapted to be received in the tape drive assembly. The use of magnetic tape cassettes is common in the computer industry, where such magnetic tape has a defined width, and a number of tracks, wherein information can be written and subsequently read by appropriately positioned magnetic heads. There is a tendency to provide an increasing number of tracks on a strip of magnetic tape to maximize the amount of information which may be contained therein. As a result of this increasing number of tracks, it has become more and more critical that locating a particular track is carried out with speed and accuracy for precision reading of information contained in that track. By "locating" a particular track is meant that a magnetic read or write head be positioned with respect to the magnetic tape so that the head accurately and precisely corresponds with the track for efficient retrieval of the information thereon. In order for the magnetic head to read from or write onto a track, it is necessary that the tape drive assembly provide a mechanism whereby the tape head can be displaced in a direction normal to the movement of the tape so that the tape head can move up and down across the width of the tape for the purposes of locating a track. Typically, a head carriage assembly is mounted on a spindle or shaft which may be rotated by a motor, the spindle being threaded and engaging a threaded bore in the head carriage assembly. Rotation of the spindle results in up and down movement of the magnetic head. In order to insure maximum read/write efficiency, the precise orientation and position of the magnetic head should be properly set, and the motor driving the head carriage assembly must be accurately programmed so as to stop the magnetic head in a manner which will cause it to directly register with or correspond to a desired track. European Patent Application No. 0 148 999 discloses a head position controlling device for maintaining a prescribed position of the head with respect to a multi-track magnetic tape. However, the device disclosed therein is incapable of providing a custom setting to allow alignment of a head with a tape according to the specific tolerances of a particular tape drive assembly. It is a purpose of the present invention to provide a method and apparatus which permit custom setting and programming of a particular tape drive assembly. The invention therefore relates to a method and apparatus which permit accurate setting of the orientation of the magnetic head on the carrier. Summary of the Invention According to one aspect of the invention, there is provided an magnetic tape recording/reproducing apparatus as defined in claim 1. The first portion of the support means may comprise a lower plate and the second portion of the support means comprises an upper plate, the first and second ends of the shaft member being located between the lower and upper plates of the support respectively. The lower plate preferably has a first aperture therein, and the upper plate preferably has a second aperture therein, the first and second apertures being axially aligned, wherein the first end of the shaft member is pivotedly mounted in the first aperture, and the second end of the shaft member is received in the second aperture and is movable therein. The second end of the shaft member may be retained in the second aperture by a ring member, the ring member having an outer diameter less than the diameter of the aperture whereby the ring member and second end of the shaft member are movable in the second aperture. Conveniently, the adjuster member is mounted on the upper plate, the adjuster member further comprising pivot means between the securing portion and the connecting portion thereof, movement of the securing portion pivoting the adjuster member about the pivot means to thereby adjust the position of the connecting portion and the ring member engaged thereto. The adjuster member may have its securing portion secured to the plate support by at least one clamping screw. The securing portion preferably has an adjusting aperture therein, the support means has a base aperture therein which partially registers with the adjusting aperture in the securing portion, the apertures being eccentric with respect to each other, the adjusting and base apparatus further comprising an adjusting tool adapted to extend through the adjusting aperture in the securing portion and engage the base aperture in the plate support, whereby pivoting of the adjusting tool in the base aperture causes the adjusting tool to engage walls defining the adjusting aperture in the securing portion, thereby moving the securing portion and the adjuster plate relative to the plate support. Preferably, the connecting portion comprises two substantially parallel arms, the arms defining a space therebetween, the second end of the shaft member being received within the space and abutting the parallel arms, the movement of the adjuster member being accompanied by movement of the parallel arms and axial displacement of the second end of the shaft member. According to another aspect of the invention, there is provided a method for orienting a magnetic tape head in a tape drive assembly as defined in claim 23. Brief Description of the Drawings Figure 1 is a perspective view of a tape drive frame for use with a computer, the frame being adapted to receive a magnetic tape cassette. Figure 2 is a partial side view of the frame shown in Figure 1 viewed from the direction of arrow B, the frame having been fitted with various components. Figure 2(a) is an enlarged diagrammatic view showing adjustment of the tape drive frame; Figure 3 is a top view of the portion of the frame shown in Figure 2. Figure 4 is a detail top view of the lead screw shaft and assembly, as shown in Figure 3. Figure 5 is a side view of the lead screw shaft, with various surrounding components omitted to show more clearly the structure of the shaft. Figure 6 is a plan view of the head carriage assembly, shown mounted on the lead screw shaft. Figure 7 is a side view of the head carriage assembly shown mounted on the lead screw shaft. Figure 8 is an exploded perspective detail view showing the upper end of the lead screw shaft and ring mounted to the frame. Figure 9 is a plan view of the adjuster assembly. Figure 10 is a side view of the adjuster assembly viewed from arrow C in Figure 9. Figure 11 is a side view of the adjuster plate viewed from arrow D in Figure 9. Figure 12 is a detailed side view showing the upper portion of the lead screw shaft in a first position with respect to the frame. Figure 13 is a detailed side view showing the upper portion of the lead screw shaft in a second position with respect to the frame. Figures 14 and 15 show diagramatic representations of the lead screw assembly in an exaggerated tilt to illustrate the first and second positions thereof when moved by the adjuster assembly. Figure 16 is a side view of the motor and gear upon which the lead screw assembly is mounted, showing the direct drive and gear reduction. Detailed Description of the Preferred Embodiments Reference is now made to Figure 1 to 16 of the drawings. In Figure 1, there is shown a tape drive frame 10 adapted to be connected with, for example, a computer. The frame 10 generally comprises a base 12, and a side wall 14 at one edge of the base 12. The side wall 14 defines a slot 16 through which a magnetic tape cassette 18, indicated in staggered lines in Figure 1, can be inserted and withdrawn. The frame 10 is equipped with various motors and elements which permit insertion and withdrawal of the tape cassette 18, none of which are shown in the present illustrations, and which are not pertinent to the present invention. The magnetic tape cassette 18 has located therein a length of magnetic tape mounted about spindles, whereby the tape can be moved from one spindle to another in such a manner so as to present a specific portion of the magnetic tape to a magnetic tape head for reading, as will be discussed in further detail below. The frame 10 comprises a motor support plate 20 having an aperture 22 therein. In use, and as described in further detail hereunder, a motor 24 is mounted on the motor support plate 20, the motor driving a shaft 26 extending through the aperture 22, and a motor gear 28 mounted at the end of the shaft 26 remote from the motor 24. This arrangement is best illustrated in Figure 16. The frame 10 further comprises a lower plate 30 and an upper plate 32 above the lower plate 30, the lower and upper plates being adapted to support the lead screw shaft and head carriage, described fully hereunder. The lower and upper plates 30 and 32 are separated by a vertical column 34. The lower plate 30 has an aperture 36 while the upper plate 32 comprises a slot 38 coaxial with aperture 36. The upper plate 32 is comprised of an upper step portion 40, a lower step portion 42 and a cantilever shelf portion 44 extending inwardly with respect to the frame from the lower step portion 42. The slot 38 is located in the shelf portion 44. The upper step portion 40 is approximately L-shaped, and is joined to the lower step portion 42 by means of a connecting piece 46. The upper plate 32 and lower plate 30 are positioned such that, when the lead screw shaft and head carriage are mounted between aperture 36 and slot 38, the tape head will access a portion of the tape in the magnetic tape cassette through an opening in the cassette. The frame is further equipped with tape cassette driving means, not shown, for rotating the spindles and therefore moving the tape. A lead screw shaft 48, of generally cylindrical shape, is mounted between aperture 36 and slot 38 in the lower plate portion 30 and upper plate 32. The screw shaft 48 has threads 50 along substantially its entire length. The screw shaft 48 has a mounting shaft 52 at its lower end which extends through the aperture 36 and is connected to gear 54, shown in, for example, Figures 2, 5 and 16. The gear 54 is adapted to engage the motor gear 28 such that the motor, when activated, rotates the screw shaft 48 through shaft 26, motor gear 28, gear 54 and mounting shaft 52. It is to be noted that the gear ratio between the relatively small motor gear 28 and relatively large gear 54 substantially enhances the resolution per step in the movement of the head carriage assembly when mounted on the lead screw shaft 48 as described hereunder. At the base of the screw shaft 48, there is located a disk shaped flange 56 which rotates with the screw shaft 48. At one point on its circumference, the flange 56 comprises a projection 58, which rotates with the flange 56. The projection 58 is adapted to engage with the head carriage when the head carriage is at its lowermost point with respect to the screw shaft 48, thereby preventing further rotation of the screw shaft 48. This feature will be described in further detail below. The upper end of the screw shaft 48 comprises a protruding portion 60 of generally disk shape, and coaxial with the central axis of the screw shaft. The protruding portion 60 and screw shaft 48 define a step, the horizontal component 62 of which step is generally flush with or below the level of the lower surface of cantilever shelf portion 44. The protruding portion 60 is above the level of the lower surface of shelf portion 44, extending into the slot 38. A ring 64 (best seen in Figure 8) is inserted into the slot 38 from the upper end thereof. The ring 64 comprises a hollow cylindrical portion 66, and a flange 68 at the upper end of the cylindrical portion. The outer diameter of the flange 68 is slightly greater than the width of the slot 38 thereby preventing the ring 64 from passing through the slot 38. The outer diameter of the hollow cylindrical portion 66 is slightly less than the width of the slot 38, thus permitting a small amount of movement or sliding of the ring 64 inside the slot 38. The ring 64 is inserted in the slot 38 such that the flange 68 rests on the upper surface of the shelf portion 44, the screw shaft 48 with protruding portion 60 being located in the hollow space of the cylindrical portion 66. The protruding portion 60 is secured to the ring 64 by means of a washer and U-shaped clamp 70, best illustrated in Figures 3 and 4. From the above description, it will be appreciated that the lead screw shaft 48 is firmly mounted for rotation between lower plate 30 and upper plate 32. At its lower end, the screw shaft 48 is fixed to the gear 54 and cannot be axially displaced therefrom, although pivoting of the shaft about such point is possible. At its upper end, the screw shaft 48 is secured to the ring 64, which is mounted in the slot 38. Since the cylindrical portion 66 of ring 64 is of slightly smaller diameter than the width and the length of the slot 38, some movement of the ring 64 in the slot 38 is tolerated, and movement of the ring 64 results in concomitant movement of the screw shaft 48. Thus, movement of the ring 64 in the slot 38 results in some displacement of the screw shaft 48, and the axis of the screw shaft 48 may be angled relative to the vertical longitudinal axis thereof. A head carriage assembly 72 is mounted on the lead screw shaft 48. The head carriage assembly, best illustrated in Figures 2, 6 and 7, comprises a tape head 74 and a tape head support 76. The tape head support 76 comprises a central post 78 having an aperture 80 therein, the aperture 80 having an internal thread which mates with the threaded outer surface of the lead screw shaft 48. The tape head support 76 further comprises an outwardly extending arm 82 approximately tangential to the aperture 80. Connected to the outwardly extending arm 80 is an S-shaped pivot arm 84 having a first portion 86 which connects to the outwardly extending arm 82, a transverse portion 88 and a second portion 90. The second portion 90 has a notched groove 92 along one side thereof, adapted to accommodate a pin 94 which is mounted to the frame 10. An anti-rotation spring 96 extends from the second portion 90 to the central post 78. The spring 96 acts on a half nut 97 which is thereby pushed against the screw shaft 48. The effect of the pin 94 on the pivot arm 84, and the spring 96 and half nut 97, is that the tape head support 76 is prevented from rotating about the axis of the lead screw shaft 48 when the latter is caused to rotate by the motor 24. Since the tape head support 76 is prevented from rotational movement, rotation of the screw shaft 48 thereby causes the tape head support 76 to be raised or lowered, according to the direction of rotation of the screw shaft. The undersurface 98 of the central post 78 has a disk-like flange 100, best illustrated in Figure 7. The flange 100 has a projection 102, designed to engage with the projection 58 of the flange 56 at the base of the screw shaft 48. With reference to Figure 7, it is to be noted that rotation of the screw shaft 48 either causes the head carriage assembly 72 to be raised in the direction of arrow X, or to be lowered in the direction of arrow Y. When the central post 78 approaches the flange 56, projection 102 is also lowered, until it reaches a point where it engages the rotating projection 58 on the flange 56. Engagement of the projections 58 and 102 prevents further rotation of the screw shaft 48, and thus further lowering of the head carriage assembly 72. Extending from the central post 78 are two mounting arms 104 and 106. The mounting arms 104 and 106 support the tape head 74. The tape head 74 has a tape contact surface 108 on one side thereof, and a series of leads 110 away from the head for carrying signals to and from the tape head 74. As described fully above, the head carriage assembly 72 is mounted, by means of its central post 78, about the lead screw shaft 48 for upward and downward movement on the shaft 48. It will be appreciated that, over and above any rotational movement of the lead screw shaft resulting in upward and downward movement, other movement, realignment or reorientation of the lead screw shaft will have a corresponding effect on the movement of the head carriage assembly 72, and particularly the tape contact surface 108. As fully described above, the lead screw shaft 48 is mounted with respect to the frame so that the central axis of the lead screw shaft 48 is capable of angular displacement relative to the axis of the aperture 36 and slot 38. Thus, axial dislocation of the lead screw shaft 48 will have a corresponding effect on the tape contact surface 108, which can be angularly displaced or reoriented by appropriate adjustment of the lead screw shaft 48 in its mounting in the frame 10. The importance of this capability to finely adjust the position of the tape contact surface 108 is manifest, since a more precise or accurate contact can thereafter be made between the tape contact surface 108 and the tape in the magnetic tape cassette. Further description of this adjustment, and its importance, is set out below. At this point, the position of the motor 24 relative to the lead screw shaft 48 is highlighted. In the embodiment described, the motor 24 is mounted on the frame laterally adjacent the lead screw shaft 48, as opposed to immediately below it. Two advantages result from this configuration. The first advantage is that the frame can be considerably thinner than if the motor were located below the lead screw shaft 48, a configuration which is common in existing tape drives. By locating the motor laterally adjacent the lead screw shaft, the additional thickness required thereby in the frame can be avoided, which results in a more space efficient and compact tape drive assembly. Since considerations of space and compactness are important in the ongoing efforts to reduce the size of components which comprise a computer, this structure is an important advantage. A second advantage of the system is that a gear ratio between the motor gear 28 and gear 54 can be achieved which results in increased resolution per step and thus accuracy and precision in the disposition of the tape head 74 which respect to the magnetic tape. Since the motor gear 28 is, relatively speaking, very small in comparison to the gear 54, small unintended movements caused by the motor to the motor gear 28 will have very little effect on the position of the tape head 74. In tracking the magnetic tape by locating the tape head 74 with respect thereto, a process to be described more fully hereunder, the tape head 74 must be accurately positioned, and this is achieved by programmed instructions to the motor for a predetermined number of turns or steps in order to reach that position. If the motor slightly exceeds or falls slightly short of the precise number of turns, the difference in the number of turns will not significantly effect the final position of the tape head 74 in the embodiment herein described. For example, an additional half turn of the motor gear 28 will result in the gear 54 being rotated only fractionally, and the position of the gear carriage assembly 72 will be displaced, if at all, only a minute distance which would not significantly effect the position of the tape head 74. Reference is now made to Figures 9, 10 and 11, which illustrate the adjuster assembly used for adjusting the angular axial orientation of the lead screw shaft 48 to the desired position. The adjuster assembly 112 comprises a securing portion 114 and an adjuster portion 116, the securing portion 114 being raised with respect to the adjuster portion 116 and separated therefrom by a vertical wall 118. The securing portion 114 is generally located on the upper step portion 40 of the frame 10, while the adjuster portion 116 is located over the lower step portion 42 and cantilever shelf portion 44. The vertical wall 118 lies generally adjacent the connector piece 46 between the upper step portion 40 and the lower step portion 42. The adjuster portion 116 comprises a flat plate 120 with a pair of fingerlike projections 122 and 124 extending therefrom. The fingerlike projections 122 and 124 define a rectangular space 126. The space defined between the finger projections 122 and 124 has a distance which is substantially identical to the outer diameter of flange 68 of ring 64. The flat plate 120 has a fulcrum 128 on the underside thereof, which is received in aperture 130 located in the lower step portion 42 of upper plate 32. The fulcrum projection 128 has a diameter which is substantially identical to the diameter of aperture 130; thereby permitting some pivotable movement of the adjuster assembly 112 about the axis of aperture 130, but there is no "play" or lateral movement permitted by the fulcrum projection 128 in the aperture 130. The securing portion 114 has three substantially equispaced holes 132, 134 and 136 therethrough. In the frame 10, the upper step portion 40 has three substantially corresponding holes. The hole 138 corresponds with hole 132, hole 140 corresponds with hole 134, and hole 142 corresponds with hole 136. The holes 138 and 140 on the upper step portion have an internal thread. The holes 138 and 140 register with holes 132 and 134, and are of slightly larger diameter than the holes 132 and 134. The hole 136 in the securing portion 114 is of slightly greater diameter than the hole 142 on the upper step portion, and the holes 136 and 142 are slightly axially misaligned and therefore eccentric with respect to each other, for purposes to be discussed fully hereunder. A screw 145 extends through the hole 132 and threadedly engages hole 138, in order to secure the adjuster assembly 112 to the upper plate 32. A further screw 146 extends through hole 134 and threadedly engages hole 140 for the same purpose. Since the diameters of holes 132 and 134 are slightly greater than the diameters of holes 138 and 140, the adjuster assembly 12 may be secured to the upper plate 32 over a small but varying range of positions, since tolerance for adjustment is provided. In use, the adjuster assembly 112 is located over the upper plate 32, as described above. The fingerlike projections 122 and 124 straddle the ring 64, such that the outer diameter of the flange 68 thereof abuts, or is in contact with, the inside edges of fingerlike projections 122 and 124. The fulcrum projection 128 is received inside aperture 130 and is pivotable therein, Hole 138 registers with hole 132 and screw 145 is inserted to secure the adjuster assembly 112 to the upper plate 32. The hole 134 registers with hole 140, and screw 146 is also used for securing purposes. Hole 136 partially registers with hole 142, both holes remaining open with no bolt, screw or other securing means passing therethrough. An adjuster tool 144, shown in Figures 2 and 2(a) is provided. The adjuster tool 144 comprises a substantially cylindrical elongated portion 146 and a tapering portion 148. The diameter of the tapering portion 148 at its smallest cross-section is less than the diameter of the hole 142. The diameter of the tapering portion 148 at its point of greatest cross-section exceeds the diameter of the hole 142. With the screws 145 and 146 in a snug condition, the position of the adjuster assembly 112 can be varied by inserting the adjuster tool 144 into the holes 136 and 142. When the tool 144 abuts against the edges defining hole 142 and/or hole 136, further downward movement through the hole 142 is no longer possible. Thereafter, the tool 144 can be pivoted about the point at which it is fixed, and such movement will cause the tapering portion 148 of the tool 144 to engage the sidewalls defining the hole 136 and/or hole 142. The effect of this movement can best be seen with respect to Figures 2, 2(a) and 9. A sufficient force on the tool 144 against the walls defining holes 136 and/or 142 will cause the adjuster assembly 112 to move, such movement comprising pivoting about the fulcrum projection 128. Movement of the adjuster assembly 112, about fulcrum projection 128 causes corresponding movement of the fingerlike projections 122 and 124, which movement is in turn transferred to the ring 64. The slight movement of the ring 64 adjusts the position of the upper end of the lead screw shaft 48 which, as described above, is pivotable about its lower end, for example, the mounting shaft 52. Extent of movement of the lead screw shaft 48 can be seen in Figures 12 and 13, while exaggerated tilt of the screw as a result of such movement is illustrated in Figures 14 and 15. The head carriage assembly 72, mounted to the lead screw shaft 48 as detailed above, will undergo an adjustment of its position in response to the movement of the adjuster tool 144. When the tape head 74 is in precisely the desired position, the clamping screws 144 and 146 are tightened to securely hold the adjuster assembly 112 to the frame, and to retain the lead screw shaft 48 and head carriage assembly 72 in the desired fixed position. Under normal circumstances, the adjuster assembly 112 will be set at the factory prior to installation of the tape drive into the computer, and under normal circumstances, no further adjustment will be necessary. However, if misalignment between the tape head 74 and the magnetic tape should arise due to a slow movement or settling over time, or a sudden shock movement, resetting of the precise position of the head carriage assembly 72 can be made using the techniques described above. The above device therefore provides a frame for a tape drive, the thickness of which can be substantially reduced as a result of location of the motor laterally adjacent the lead screw shaft as opposed to below such shaft. In existing devices, reduction in the thickness of the frame is usually accompanied by a reduction in the precision in critical alignment which can be set between the tape head and the tape tracks. Thus, as the frame is made thinner and the components smaller, accuracy may be sacrificed and tracking becomes more difficult. The present device attempts to overcome this disadvantage by placing the motor laterally adjacent the lead screw shaft, providing a very favorable and efficient gear ratio, and a direct drive from the motor to the lead screw shaft. The effect of the favorable gear ratio and direct drive system permits for greater accuracy in setting the motor and head carriage assembly for accurate and precise tracking of the magnetic tape.

Claims: A magnetic tape recording/reproducing apparatus presenting an apparatus for orienting a magnetic tape head in a tape drive assembly adapted to receive a magnetic tape with tracks thereon, the apparatus comprising: a frame (10) having support means (30, 32); a shaft member (48) having an axis and mounted for rotation about its axis in the support means; a motor (24) connected to the shaft for rotating the shaft member about its axis; and a head carriage assembly (72) including magnetic tape head (74) mounted on the shaft member, the head being positioned in the tape drive assembly such that the head lies adjacent magnetic tape adapted to be received in the tape drive assembly, the head carriage assembly being movable over the shaft member in response to rotation thereof whereby the head moves linearly in a direction substantially normal to movement of the tape to permit the head to locate and align with the tracks on the tape, characterized in that; the shaft member has a first end pivotably mounted on a first portion of the support means, and a second end mounted on a second portion of the support means and movable relative thereto, such movement causing pivoting of the shaft member at its first end, and said apparatus further comprises: an adjuster member (112) having a securing portion (114) adapted to be moved with respect to and secured to the support, and a connecting portion (116) adapted to engage and move the second end of the shaft member, whereby the movement of the securing portion adjusts the orientation of the shaft member and head carriage assembly in a direction parallel to the movement of the tape, the securing portion being firmly secured to the support when the head is in a desired orientation. Apparatus as claimed in Claim 1 wherein the first portion of the support means comprises a lower plate (30) and the second portion of the support means comprises an upper plate (32), the first and second ends of the shaft member being located between the lower and upper plates of the support respectively. Apparatus as claimed in Claim 2 wherein the lower plate has a first aperture (36) therein, and the upper plate has a second aperture (38) therein, the first and second apertures being axially aligned, wherein the first end of the shaft member is pivotedly mounted in the first aperture, and the second end of the shaft member is received in the second aperture and is movable therein. Apparatus as claimed in Claim 3 wherein the second end of the shaft member is retained in the second aperture by a ring member (64), the ring member having an outer diameter less than the diameter of the aperture whereby the ring member and second end of the shaft member are movable in the second aperture. Apparatus as claimed in Claim 4 wherein the ring member comprises a cylindrical portion (66) for location in the second aperture and of lesser diameter than said second aperture, and a flange at an upper end of the cylindrical portion, the flange being of greater diameter than at least a portion of the second aperture whereby the ring is prevented from moving through the aperture. Apparatus as claimed in Claim 5 wherein the connecting portion of the adjuster member engages the flange of the ring member. Apparatus as claimed in Claim 6 wherein the adjuster member is mounted on the upper plate, the adjuster member further comprising pivot means (128) between the securing portion and the connecting portion thereof, movement of the securing portion pivoting the adjuster member about the pivot means to thereby adjust the position of the connecting portion and the ring member engaged thereto. Apparatus as claimed in Claims 5, 6, or 7 wherein the second end of the shaft member is stepped, there being a smaller diameter projection (60) at the second end, the projection being secured to the ring member with securing means. Apparatus as claimed in Claims 2 to 8, wherein the upper plate comprises an upper step portion (40), a lower step portion connected to the upper step portion by a connecting piece (46), and a shelf portion (44), the upper step portion being adapted to receive the securing portion of the adjuster member, the lower step portion and shelf member being adapted to receive the connecting portion of the adjuster member, the second aperture being located in the shelf portion. Apparatus as claimed in any one of the preceding claims wherein the shaft member is threaded, and the head carriage assembly has a threaded bore (80) engaging with the shaft member, rotation of the shaft member causing movement of the head carriage assembly thereover in an upward or downward direction, depending upon the direction of rotation of the shaft member. Apparatus as claimed in Claim 10 wherein the shaft member comprises a disk shape flange (56) near its first end, the shaft and flange being substantially coaxial. Apparatus as claimed in Claim 11 wherein the shaft member further comprises stop means (58), said stop means engaging the head carriage assembly to prevent further downward movement thereof. Apparatus as claimed in Claim 12 wherein the stop means comprises a projection on the flange at the first end of the shaft, the projection being adapted to engage a counter-surface (102) on the head carriage assembly, said engagement preventing further rotation of the shaft member in a direction for lowering the head carriage assembly. Apparatus as claimed in Claim 10 wherein the shaft member further comprises an extension shaft (52) extending from the first end of the shaft member and being substantially coaxial therewith, one end of the extension shaft being fixed to the first end of the shaft member, the other end of the extension bar being fixed to a shaft gear wheel (54). Apparatus as claimed in Claim 14 wherein the motor has extending therefrom a motor shaft (26) with a motor gear wheel (28) thereon, the shaft gear wheel and motor gear wheel being in direct contact with each other to form a gear train whereby the motor is able to drive the shaft member. Apparatus as claimed in Claim 15 wherein the shaft gear wheel is of relatively large diameter, and the motor gear wheel is of relatively small diameter, thereby providing a high gear ratio so that a significant movement of the motor gear wheel is required to move the head carriage assembly. Apparatus as claimed in Claim 16 wherein the motor is mounted on the frame substantially adjacent and spaced from the shaft member, the shaft gear wheel extending downwardly from the shaft member and the motor gear wheel extending downwardly from the motor, the motor gear wheel and shaft gear wheel being substantially coplanar. Apparatus as claimed in any one of the preceding claims wherein the adjuster member has its securing portion secured to the plate support by at least one clamping screw (145, 146). Apparatus as claimed in any one of the preceding claims, wherein the securing portion has an adjusting aperture (136) therein, the support means has a base aperture (142) therein which partially registers with the adjusting aperture in the securing portion, the apertures being eccentric with respect to each other, the adjusting and base apertures further comprising an adjusting tool (144) adapted to extend through the adjusting aperture in the securing portion and engage the base aperture in the plate support, whereby pivoting of the adjusting tool in the base aperture causes the adjusting tool to engage walls defining the adjusting aperture in the securing portion, thereby moving the securing portion and the adjuster plate relative to the plate support. Apparatus as claimed in Claim 19 wherein the adjuster member further comprises the pivot means (128) interjacent the securing portion and connecting portion of the adjuster member, the pivot means engaging in a pivot aperture (130) of the support means, whereby movement of the securing portion by means of the adjusting tool causes the adjuster member to pivot about the pivot projection resulting in corresponding radial movement of the connecting portion. Apparatus as claimed in any one of the preceding claims wherein the connecting portion comprises two substantially parallel arms (122, 124), the arms defining a space (126) therebetween, the second end of the shaft member being received within the space and abutting the parallel arms, the movement of the adjuster member being accompanied by movement of the parallel arms and axial displacement of the second end of the shaft member. Apparatus as claimed in Claim 13 wherein the head carriage assembly comprises a central mounting portion (78) defining the threaded bore, the central mounting portion having a lower surface with the counter-surface extending therefrom. A method for orienting a magnetic tape head in a magnetic tape recording/reproducing apparatus as defined in any of the preceding claims comprising the steps of: determining the desired orientation of the tape head on the head carriage assembly in a direction parallel to the movement of the tape such that the tape head will precisely register with tracks on the magnetic tape; adjusting the adjuster means to move the second end of the shaft member to a position such that the tape head will be in the desired position; securing the adjusting means to the support means when the tape head is in the desired position to retain the tape head in that position. A method as claimed in Claim 23 further comprising the steps of: providing a motor to rotate the shaft member; providing a gear train between the motor and the shaft member having a high gear ratio so that substantial turning of the motor is required to move the head carriage assembly over the shaft member. A method as claimed in Claim 24 further comprising placing the motor on the frame such that the motor is located in the space defined between the first and second ends.

Inventors: KUKREJA JAGMOHAN S, NAYAK ASHOK B, KUKREJA, JAGMOHAN S., NAYAK, ASHOK B.
Applicants: CONNER PERIPHERALS INC, CONNER PERIPHERALS, INC.
Application year: 1990
Main classification: G11B5
IPC codes: G11B5, G11B21