GB2302979A - Tape cassette deck with autostop mechanism - Google Patents

Abstract

A tape cassette playing mechanism 10 comprises left and right reel shafts to be driven by an electric motor 7, a plurality of gearwheels provided between the motor 7 and the shafts for drive transmission, and a plurality of operating members 11-16 arranged to control the operation of the gearwheels for the mechanism 10 to perform various tape functions. A locking member (19, fig 8) is slidable between a locking position to lock a said operating member in an operative position and an unlocking position to unlock the said operating member from the operative position. A release member 60 is provided for automatically sliding the locking member to the unlocking position when a said tape reaches an end stopping the shafts. The release member 60 is arranged to be subject to a biassing action, by a cranked wheel 30, resulting from the rotation of the shafts in order to be restrained from sliding the locking member before the tape reaches an end.

Description

CASSETTE PLAYING MECHANISM The present invention relates to a tape cassette playing mechanism which has an automatic stopping function.

Conventionally, most if not all of the existing tape cassette .playing mechanisms have an automatic stopping function for stopping the operation of the mechanisms when a tape reaches an end. The automatic stopping function usually relies on the stopping tension of the tape to operate, which has the disadvantage of inevitably overtensioning the tape.

The present invention seeks to mitigate or to at least alleviate such a disadvantage.

According to the invention, there is provided a tape cassette playing mechanism comprising left and right reel shafts to be driven by an electric motor to rotate for running a cassette tape operated by the mechanism in opposite directions, a plurality of gearwheels provided between a said motor and the shafts for drive transmission, a plurality of operating members arranged to control the operation of the gearwheels for the mechanism to perform various tape functions, a locking member movable between a locking position to lock a said operating member in an operative position and an unlocking position to unlock the said operating member from the operative position, and a release member for automatically moving the locking member to the unlocking position when a said tape reaches an end and stops rotation of the shafts, which release member is arranged to be subject to a biassing action resulting from the rotation of the shafts in order to be restrained from moving the locking member before a said tape reaches an end Preferably, the mechanism includes an actuator, and the release member is arranged to be caught by the actuator to move the locking member when the shafts are stopped from rotation by a said tape reaching an end, said release member being restrained by the biassing action from being caught by the actuator before a said tape reaches an end.

Alternatively, the mechanism includes an actuator which is arranged to catch and hence to operate the release member for moving the locking member when the shafts are stopped from rotation by a said tape reaching an end, said release member being restrained by the biassing action from being caught by the actuator before a said tape reaches an end.

More preferably, the actuator is arranged to set the release member into a reciprocating motion before a said tape reaches an end and to catch the release member only when the shafts are stopped from rotation by a said tape reaching an end.

In a preferred embodiment, the actuator is provided by a cam for setting the release member into a reciprocating motion against the biassing action, said cam having a profile which is radially expanding to form a step for catching the release member when the biassing action disappears.

More preferably, the release member has a bifurcated part having two ends for bearing against the cam, at one of which ends the release member is to be caught by the cam step when the release member is not returned by the biassing action.

In a preferred embodiment, the biassing action is provided by means of a biassing member which is in slipping frictional angular engagement with respect to one of the shafts.

More preferably, the biassing member has a crank engaging a portion of the release member in order to bias the release member.

Even more preferably, the portion of the release member has two edges to be alternatively engaged by the crank in order for the release member to be biassed in the same direction irrespective of the direction of rotation of said one of the shafts.

In a preferred embodiment, one of the operating members, which is for setting the mechanism into a pause mode, is arranged to operate a spring to provide a said biassing action upon the release member in the pause mode when the shafts are temporarily stopped and a said tape has yet to reach an end.

More preferably, the spring is carried by said one of the operating members.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front view of an embodiment of a tape cassette playing mechanism in accordance with the invention; Figure 2 is a rear view of the mechanism of Figure 1; Figures 3A and 3B are front views of two operating button plates and an associated locking slider of the mechanism of Figure 1, showing their respective conditions in tape playback and stop operations; Figure 4 is a cross-sectional side view of a right reel shaft of the mechanism of Figure 1, including a crank wheel; Figure 5 is a front perspective view of the crank wheel of Figure 4; Figure 6 is a front view of a cam gearwheel of the mechanism of Figure 2; Figure 7 is a rear view of a reciprocating member of the mechanism of Figure 2;; Figure 8 is a rear view showing how the reciprocating member of Figure 7 is acted upon by the crank wheel of Figure 5 and the cam gearwheel of Figure 6; Figures 9A to 9D are rear views showing how the cam gearwheel of Figure 6 acts upon the reciprocating member of Figure 7, and how the reciprocating member in turn acts upon the locking slider of Figures 3A and 3B; and Figures 10A and 10B are rear views showing how an elbow spring acts upon the reciprocating member of Figure 7.

Referring initially to Figures 1 to 3B of the drawings, there is shown a tape cassette playing mechanism 10 embodying the invention, which mechanism 10 has a series of six operating button plates, namely REC (record), PLAY (playback), REW (rewind), FF (fast forward), STOP and PAUSE button plates 11 to 16, and a mounting plate 17 supporting the button plates 11 to 16, as generally known in the art.

The mechanism 10 includes a pair of left and right reel shafts 8 and 9 which are to be driven by respective coaxial driving gearwheels 8W and 9W to rotate about respective axes in opposite directions X and Y. The left shaft 8 is in rigid angular engagement with the driving gearwheel 8W. The right shaft 9 is in slipping frictional angular engagement with the driving gearwheel 9w. The mechanism 10 further includes an electric motor 7 driving a flywheel 32 by means of a belt 36 to rotate in direction X. In turn, the flywheel 32 rotates a swinging clutch 40 in direction X by means of a belt 39 and has a co-axial pinion 33 to rotate a cam gearwheel 34 having a co-axial actuating cam member 35 (see also Figure 6) in direction Y.

The clutch 40 incorporates co-axially a gearwheel 28 and a pulley 29, the latter engaging the belt 39. The gearwheel 28 has a co-axial pinion 28A and is coupled with the pulley 29 through a slipping frictional angular engagement.

Electrical power is supplied to the motor 7 via a switch 6.

So long as the motor 7 is running, the flywheel 32 and the cam gearwheel 34 / cam member 35 will be driven in rotation.

The operating button plates 11 to 16 are resiliently biassed outwards by individual springs. The switch 6 is arranged to be closed upon depression of the button plates 11 to 14 (except STOP and PAUSE button plates 15 and 16) to energise the motor 7. Each of the button plates 11 to 14 has a side tab 18. The mechanism 10 includes a locking slider 19 which is arranged to lock the depression of a specific button plate (except STOP and PAUSE button plates 15 and 16) for the mechanism 10 to perform a specific tape operation. The locking slider 19 is resiliently biassed to slide in direction P by means of a coil spring 50 acting at an arm 22 of the slider 19. At each of the positions corresponding to the button plates 11 to 14, the locking slider 19 is formed with a hook 20 having an inclined cam edge 21, both facing in direction P.Each cam edge 21 is provided for abutment by the tab 18 of the respective button plate, such as the PLAY button plate 12 as shown in Figure 3A, upon depression to slide the locking slider 19 in opposite direction Q, against the action of the spring 50. The associated hook 20 subsequently catches the said tab 18, upon return in direction P, in order to lock the PLAY button plate 12 depressed, as shown in Figure 3B, for the mechanism 10 to perform tape playback operation.

The STOP button plate 15 also has a side tab 18' for, upon depression, abutting a similar inclined cam edge 21 of the locking slider 19 for sliding the locking slider 19 in direction Q, against the action of the spring 50, in order to release, for example, the previously depressed/locked PLAY button plate 12 and hence to switch off the motor 7.

Referring also to Figures 4 and 5 of the drawings, the right shaft 9 is rotated not only by the gearwheel 9W but also by a second gearwheel 9W' which is provided co-axially behind the first gearwheel 9w. The second gearwheel 9w' is in rigid angular engagement with the right shaft 9, as opposed to the first gearwheel 9W. The second gearwheel 9W' is arranged to turn, through a slipping frictional engagement with, a co-axial crank wheel 30 provided immediately behind. The crank wheel 30, which has a crank rod 31, is urged co-axially against the second gearwheel 9W' by a coil spring 37. The gearwheels 9W and 9w' are constantly in mesh with respective idle gearwheels 26 and 27.The clutch 40 is arranged to have its gearwheel 28 positioned between the gearwheels 8w and 27 and its pinion 28A adjacent the gearwheel 26.

In operation, upon depression of the PLAY button plate 12 (together with or without the REC button plate 11), the idle gearwheel 26 is swung into engagement with the pinion 28A of the clutch 40 for rotation in direction Y by the pinion 28A in order to drive the gearwheel 9W and hence the right shaft 9 in direction X at a normal speed for tape playback (or record). Upon depression of the FF button plate 14, the clutch 40 is swung to one side to have its gearwheel 28 engage with the idle gearwheel 27 for driving, via the idle gearwheel 27 rotating in direction Y, the gearwheel 9W' and hence the right shaft 9 in direction X at a relatively higher speed for tape fast forward.Upon depression of the REW button plate 13, the clutch 40 is swung to the opposite side to have its gearwheel 28 engage with the gearwheel 8W for directly driving the gearwheel 8w and hence the left shaft 8 at the same relatively higher speed but in opposite direction Y for tape rewind.

The mechanism 10 has an automatic stopping function for releasing the operating button plates 11 to 14 from depression upon reaching the end of a cassette tape operated by the mechanism 10 and hence switching off the motor 7, without relying on the stopping tension of the tape in order to avoid over-tensioning the tape.

The automatic stopping function is provided by the cam gearwheel 34 / cam member 35 and the crank wheel 30 / crank rod 31 and includes a reciprocating member 60 (separately shown in Figure 7). The reciprocating member 60 is supported for pivoting about an axis 61, and has, integrally, a bifurcated C-shaped part 62 having relatively shorter and longer ends 63 and 64, a triangular frame 65 having first and second limbs 66 and 67 provided on the same side of the axis 61, and a finger 68 provided on the opposite side of the axis 61. The C-shaped part 62 is positioned to have its inner side 62' encompassing the cam member 35. The triangular frame 65 is positioned to surround the crank rod 31.

Reference is now made to Figure 8 of the drawings. In the normal tape playback, record or fast forward operation, the right shaft 9 is driven by the first or second gearwheel 9W or 9W' to rotate in direction X and the crank wheel 30 is also turned in that direction. The turning of the crank wheel 30 is however stopped by the first limb 66 of the triangular frame 65 of the reciprocating member 60 holding the crank rod 31. This causes a slip in the frictional engagement between the second gearwheel 9W' and the crank wheel 30, permitting the second gearwheel 9W' to continue to rotate and causing the crank wheel 30 to impart upon the reciprocating member 60 a tendency or biassing action to pivot in direction Y.

The cam member 35 has an external shape resembling that of a numeral "6" or "9", having an eccentric peripheral profile 35A which is radially expanding in direction Y to form a radial step 35B. The cam member 35, upon continual rotation in direction Y, repeatedly sweeps and thus pushes against the inner side 62' of the C-shaped part 62 from the shorter end 63 to the longer end 64, thereby periodically pivoting the reciprocating member 60 in direction X against the biassing action of the crank wheel 30 and hence setting the reciprocating member 60 into an angular reciprocating motion. The shorter end 63 is sufficiently short and angularly returned in time by the crank wheel 30 at the beginning of each sweeping cycle of the cam member 35 so as not to be caught by the cam step 35B.Accordingly, the said biassing action serves to restrain the reciprocating member 60 from being caught by the cam member 35.

In the normal tape rewind operation, the left shaft 8 is driven by the gearwheel 8W to rotate in direction Y and the right shaft 9 together with the second gearwheel 9W follows through pulling of the tape to rotate in the reverse direction Y. The crank wheel 30 is thus turned in the same reverse direction Y. The reverse turning of the crank wheel 30 is stopped by the second limb 67 of the triangular frame 65 of the reciprocating member 60 holding the crank rod 31. As the second limb 67 is provided on the same side as the first limb 66 with respect to the axis 61, the reverse biassing action imparted by the crank wheel 30 likewise urges the reciprocating member 60 to turn in direction Y, that being the same condition as in the tape playback, record or fast forward operation described above.

Accordingly, the aforesaid angular reciprocating motion of the reciprocating member 60 occurs.

Reference is now made to Figures 9A to 9D of the drawings.

In the tape playback, record, fast forward or rewind operation, upon reaching the end, the tape will stop the rotation of the right shaft 9 (and hence the rigidly engaged second gearwheel 9W') and the left shaft 8 (and hence the rigidly engaged gearwheel 8W). In the playback or record operation, the frictionally engaged first gearwheel 9w will slip relative to the right shaft 9, without stalling the motor 7 and over-tensioning the tape.

In the fast forward or rewind operation, the clutch gearwheel 28 will slip relative to the clutch pulley 29, without stalling the motor 7 and over-tensioning the tape.

In each case, the gearwheel 9W' will stop rotation and cease to act upon the crank wheel 30, thereby terminating the biassing action of the crank wheel 30 upon the reciprocating member 60. The cam wheel 34 and cam member 35 are still rotated in the direction Y by the motor 7 which is still running (Figures 9A and 9B).

In the absence of the biassing action of the crank wheel 30, the reciprocating member 60 pivots in the direction X (being moved by the cam member 35), but will not pivot back in the direction Y, with the shorter end 63 of its C-shaped part 62 moving close to the cam member 35. The shorter end 63 of the C-shaped part 62 will be caught and engaged by the cam step 35B at the beginning of the next rotation of the cam member 35 (Figure 9C). As it continues to rotate, the cam member 35 will again pivot the reciprocating member 60 in direction X, but to a further extent than before, causing the finger 68 to move further ahead. The finger 68 will hit the arm 22 of the locking slider 19 (Figure 9D), thereby sliding the locking slider 19 in direction Q and hence releasing the REC, PLAY, REW or FF button plate concerned and in turn switching off the power supplied to the motor 7.

Reference is finally made to Figures 10A and 10B of the drawings. The PAUSE button plate 16 stays in alternative depressed and raised positions upon successive pressings, and carries an elbow spring 51. The spring 51 is always in tension and has an upper limb 52 which extends through a pair of supporting fingers 23 of the arm 22 of the locking slider 19 to reach a position near a side 69 of the reciprocating member 60. In the raised position of the PAUSE button plate 16 (Figure 10A), the spring limb 52 is free from the said side 69. When the PAUSE button plate 16 is depressed (Figure 10B), the spring limb 52 is pushed, through the fingers 23, to resiliently bear against the side 69, thereby biassing the reciprocating member 60 in direction Y.

While the mechanism 10 is in the tape playback, record, fast forward or rewind operation, depression of the PAUSE button plate 16 will temporarily stop the rotation of the left or right shaft 8 or 9, with the tape not yet at an end. Although the stopping of the rotation of the left or right shaft 8 or 9 will terminate the biassing action of the crank member 30 which turns the reciprocating member 60 in the direction Y, the limb 52 of the spring 51, which is now resiliently bearing against the side 69 of the reciprocating member 60, will instead provide the biassing action. Accordingly, the aforesaid angular reciprocating motion of the reciprocating member 60 will continue, otherwise the locking slider 19 would be slid by the finger 68 of the reciprocating member 60 to erroneously release the REC, PLAY, FEW or FF button plate concerned and stop the prevailing operation of the mechanism 10.

The construction and operation of the remaining parts and components of the mechanism 10 are generally known in the art and, therefore, will not be described herein.

The invention has been given by way of example only, and various modifications of and/or alterations to the described embodiment may be made by persons skilled in the art without departing from the scope of the invention as specified in the appended claims.

Claims (12)

1. A tape cassette playing mechanism comprising left and right reel shafts to be driven by an electric motor to rotate for running a cassette tape operated by the mechanism in opposite directions, a plurality of gearwheels provided between a said motor and the shafts for drive transmission, a plurality of operating members arranged to control the operation of the gearwheels for the mechanism to perform various tape functions, a locking member movable between a locking position to lock a said operating member in an operative position and an unlocking position to unlock the said operating member from the operative position, and a release member for automatically moving the locking member to the unlocking position when a said tape reaches an end and stops rotation of the shafts, which release member is arranged to be subject to a biassing action resulting from the rotation of the shafts in order to be restrained from moving the locking member before a said tape reaches an end.

2. A tape cassette playing mechanism as claimed in claim 1, including an actuator, wherein the release member is arranged to be caught by the actuator to move the locking member when the shafts are stopped from rotation by a said tape reaching an end, said release member being restrained by the biassing action from being caught by the actuator before a said tape reaches an end.

3. A tape cassette playing mechanism as claimed in claim 1, including an actuator which is arranged to catch and hence to operate the release member for moving the locking member when the shafts are stopped from rotation by a said tape reaching an end, said release member being restrained by the biassing action from being caught by the actuator before a said tape reaches an end.

4. A tape cassette playing mechanism as claimed in claim 2 or claim 3, wherein the actuator is arranged to set the release member into a reciprocating motion before a said tape reaches an end and to catch the release member only when the shafts are stopped from rotation by a said tape reaching an end.

5. A tape cassette playing mechanism as claimed in claim 4, wherein the actuator is provided by a cam for setting the release member into a reciprocating motion against the biassing action, said cam having a profile which is radially expanding to form a step for catching the release member when the biassing action disappears.

6. A tape cassette playing mechanism as claimed in claim 5, wherein the release member has a bifurcated part having two ends for bearing against the cam, at one of which ends the release member is to be caught by the cam step when the release member is not returned by the biassing action.

7. A tape cassette playing mechanism as claimed in any one of the preceding claims, wherein the biassing action is provided by means of a biassing member which is in slipping frictional angular engagement with respect to one of the shafts.

8. A tape cassette playing mechanism as claimed in claim 7, wherein the biassing member has a crank engaging a portion of the release member in order to bias the release member.

9. A tape cassette playing mechanism as claimed in claim 8, wherein the portion of the release member has two edges to be alternatively engaged by the crank in order for the release member to be biassed in the same direction irrespective of the direction of rotation of said one of the shafts.

10. A tape cassette playing mechanism as claimed in any one of the preceding claims, wherein one of the operating members, which is for setting the mechanism into a pause mode, is arranged to operate a spring to provide a said biassing action upon the release member in the pause mode when the shafts are temporarily stopped and a said tape has yet to reach an end.

11. A tape cassette playing mechanism as claimed in claim 10, wherein the spring is carried by said one of the operating members.

12. A tape cassette playing mechanism substantially as hereinbefore described with reference to Figures 1 to 10B of the accompanying drawings.