GB2092811A

GB2092811A - Drive Mechanism for Cassette Tape Recording/Reproducing Apparatus

Info

Publication number: GB2092811A
Application number: GB8202277A
Authority: GB
Original assignee: Pioneer Electronic Corp
Current assignee: Pioneer Corp
Priority date: 1981-01-30
Filing date: 1982-01-27
Publication date: 1982-08-18
Also published as: GB2092811B; JPS57127942A; DE3202902A1

Abstract

In a cassette tape recording/reproducing apparatus of the reversible type comprising a movable head base 28 having a recording/reproducing head 33 and a pair of erasing heads 31, 32 mounted thereon, a pair of capstans 4a, 5a adapted to rotate in given directions, and a pair of pinch rollers 16, 17, a drive mechanism is provided for the purposes of moving the head base 28 between the stop, intermediate and playback positions, and selecting one of the pinch rollers and the opposite one of the erasing heads. The mechanism comprises a pair of cams (12c, 13c) secured to cut-out gears 12, 13 which are independently driven in response to the selected mode of operation of the apparatus, a cam follower 22 displaceable by the rotation of one or both of the cams, means for moving the head base 28 back and forth in response to any displacement of said cam follower, and means for selecting proper ones of the pinch rollers and erasing heads. The rotational force of the cut-out gear is utilized to move the head base, control the pinch rollers and erasing heads, rotate the head 33 by 180 DEG upon a change of feed direction, and operate tape reel brake shoes 37, 38. <IMAGE>

Description

SPECIFICATION Drive Mechanism for Cassette Tape Recording/Reproducing Apparatus Background of the Invention This invention relates to a drive mechanism for a cassette tape recording/reproducing apparatus comprising a head base having a recordingireproducing head and a pair of erasing heads mounted thereon and being movable among the stop position, the intermediate position for fast forward and the playback position for recording and playback operations.

One of prior art drive mechanisms uses a solenoid to move the head base to the intermediate or playback position. Another prior art drive mechanism uses two separate solenoids for moving the head base and for driving the pinch roller into contact with the capstan. The solenoids must be of a sufficient capacity to directly move the head base or pinch roller, and such a drive mechanism thus have the drawbacks of large size, increased cost and increased power consumption.

It is an object of the present invention to provide an improved drive mechanism for a cassette tape recording/reproducing apparatus which is of a relatively simple structure and ensures reliable operation.

Summary of the Invention The present invention provides an improvement in a cassette tape recordingireproducing apparatus, specifically of the reversible tape, comprising a head base having a recording/reproducing head and a pair of erasing heads mounted thereon and being movable among the stop, intermediate and playback positions, a pair of capstans adapted to rotate in given directions, and a pair of pinch arms each having a pinch roller pivotally mounted. The erasing heads, capstans and pinch rollers in pairs are arranged symmetrically with respect to the recording/reproducing head.A drive mechanism for a cassette tape recording/reproducing apparatus of this type according to the present invention, comprises a pair of cams adapted to be independently driven in response to the selected mode of operation of the apparatus, a cam follower having at both ends two control pins adapted to engage with said cams when the cams rotate, the cam follower being displaceable by the rotation of one or both of the cams, and means for moving the head base back and forth in response to any displacement of the cam follower. The head base is moved to the intermediate position in response to a slant displacement of the cam follower caused by the rotation of either of the cams. The head base is further moved to the playback position in response to a parallel displacement of the cam follower caused by the rotation of both of the cams.

Prior to the present invention, the inventor proposed a drive mechanism in which a solenoid is used to trigger a cut-out gear to allow the cutout gear to mesh with the rotating capstan gear.

The rotational force of the cut-out gear is utilized to control the movement of the head base and pinch roller. In this mechanism two biasing springs are separately provided for restoring the solenoid and for bringing the cut-out gear into mesh with the rotating gear. A number of parts are required and the springs used must be of an increased resilience in order to ensure reliable operation. Accordingly, a solenoid of an increased power must be used to overcome the spring action.

It is another object of the present invention to provide a drive mechanism for a cassette tape recording/reproducing apparatus in which a single spring commonly functions for both the restoration of a solenoid and actuation of a cutout gear to mesh with the rotating capstan gear.

In order that the rotational force of the cut-out gear is utilized to drive the head base and other parts, the cut-out gear is provided.with the coaxial cam which the cam follower follows to transmit the rotational force of the cam to the head base. If the cam follower is always in contact with the cam, an increased force is required to rotate the cut-out gear a small angle immediately before its meshing with the capstan gear. A biasing spring of an increased resilience is thus needed to actuate the cut-out gear.

It is thus a further object of the present invention to provide a drive mechanism for a cassette tape recording/reproducing apparatus in which the cam follower is not in contact with the cam when the cut-out gear is in the stop position, enabling a biasing spring for actuating the cut-out gear to be of a reduced resilience.

In a preferred embodiment of the present invention, selective means is operatively connected to the cam follower and to the pinch arms for selecting one of the pinch arms in response to a slant displacement of the cam follower caused by the rotation of either of the cams. The selective means and the head base moving means are mechanically coupled and include the cam follower, a pair of hooks pivotally connected to the cam follower, and a connecting plate having a strip attached thereto and swingable to a location allowing said strip to be engaged by either of the hooks. The slant displacement of the cam follower causes not only the connecting plate to swing to the location allowing strip-hook engagement, but also the corresponding hook to advance, thereby advancing the connecting plate. As a result, the head base is advanced to the intermediate position.When both the cams are rotated, the cam follower is displaced in parallel, thereby bringing the above-selected pinch roller in pressure contact with the corresponding capstan as well as advancing the head base to the playback position.

A prior art driven mechanism for a cassette tape recording/reproducing apparatus of the reversible type uses a solenoid for each of the pinch rollers. By energizing either of the solenoids, one of the pinch rollers is selected in accordance with the forward or reverse operation, to thereby urge the selected pinch roller in pressure contact with the capstan. The use of two solenoids for driving either of the pinch rollers is wasteful and undesired in view of the compactness of the apparatus.

According to the present invention, a pinch arm-drive lever is provided in conjunction with the cam follower. The pinch arm-drive lever is pivotally connected to the connecting plate and engageable with either of the pinch arms when the connecting plate is swung to one location.

The connecting plate and the pinch arm-drive lever cooperate to bring the selected pinch roller in pressure contact with the corresponding capstan. Thus, the movement of the head base and the selection and pressure contact of the pinch roller can be achieved by means of a common drive mechanism. It is also possible to utilize the pinch arm-drive lever to select one of the erasing heads in accordance with the forward or reverse direction of operation.

In a further preferred embodiment, a movable head mount having a pair of erasing heads secured thereto is pivotally mounted on the head base. Thus the erasing head mount is moved with the head base. Preferably, the erasing head mount is selectively pivoted by means of the pinch armdrive lever. Then, in response to a slant displacement of the cam follower caused by the rotation of either of the cams, the corresponding one of the pinch arms and erasing heads is selected by the pinch arm-drive lever so that the selected pinch arm and hence, the pinch roller is brought in pressure contact with the capstan and the erasing head is moved to the tape path.

Brief Description of the Drawings Fig. 1 is an elevational view of a drive mechanism incorporated in a cassette tape recording/reproducing apparatus according to the present invention; Fig. 2 is an elevation view of the drive mechanism similar to Fig. 1, but when viewed from a chassis toward the rear; Fig. 3 is an exploded perspective view showing the members constructing the drive mechanism and located in front of the chassis; Fig. 4 is an exploded perspective view showing the remaining members constructing the drive mechanism and located in rear of the chassis; Fig. 5 illustrates a cut-out gear and associated members; Fig. 6 illustrates the movement of the members in the cue operation; Fig. 7 illustrates the movement of the members in the playback operation; Fig. 8 illustrates the movement of the members in the reversing operation; and Fig. 9 is a view similar to Fig. 5, showing the cut-out gear and cam follower under impact.

It should be noted that the cassette tape recording/reproducing apparatus having a drive mechanism according to the present invention is ordinally used at the normal setting as shown in the elevational view of Fig. 1. Accordingly, the terms "vertical" and "lateral" directions are used under the assumption that the apparatus is in the normal setting, and correspond to top-to-bottom and right-to-left directions in Fig. 1.

Description of the Preferred Embodiment Referring to Figs. 1 to 4, a cassette tape recording/reproducing apparatus in which a drive mechanism according to the present invention is incorporated is shown as comprising a vertically and laterally extending chassis 1 and a first substrate 2 fixedly secured to the main rear surface of the chassis 1 with an appropriate spacing. On the first substrate 2, coils 2a for constituting a capstan motor to be described later are placed and bearing 2b and 2c for capstan shafts are fixedly secured as best seen from Fig. 4.

Located at the rear of the first substrate 2 is a second substrate 3 in the form of a printed circuit board having an electrical circuit for controlling electrical conduction of electric components including the coils 2a of the capstan motor and reel motors and plungers to be described later. The capstan motor in the form of a first flywheel 4 has magnets (not shown) secured to its rear surface so as to face the coils 2a and a first capstan shaft 4a axially extending therefrom. The first flywheel 4 is also provided with a concentric gear 4b. The first capstan shaft 4a is journalled at the rear end by the bearing 2b on#the first substrate 2 and extended through a bearing 1 a in the chassis 1 so that the front end projects beyond the front surface of the chassis 1.A second flywheel 5 also has a second capstan shaft 5a axially extending therefrom and a concentric gear 5b. The second capstan shaft 5a is journalled at the rear end by the bearing 2c on the first substrate 2 and extended through a bearing 1 b in the chassis 1 so that the front end projects beyond the front surface of the chassis 1. These projecting portions of the first and second capstan shafts 4a and 5a serve as capstans coacting with pinch rollers.

A pulley 6 is journalled on a shaft (not shown) extending perpendicular to the chassis 1. A belt 7 is trained around the first and second flywheels 4 and 5 and the pulley 6 such that the second flywheel 5 is rotated via the belt 7 as the second flywheel or capstan motor 5 rotates.

Right and left solenoids 8 and 9 secured to the rear surface of the chassis 1 have suction rods 8a and 9a extending vertically downward therefrom.

Right and left trigger levers 10 and 1 1 are journalled on pivots (not shown) extending perpendicular to the rear surface of the chassis 1.

The trigger levers 10 and 1 1 have engaging pins 1 Oa and 1 a engaged with the ends of the solenoid suction rods 8a and 9a. The right and left trigger levers 10 and 11 are also provided with engaging claws 1 Ob and 1 b adapted to engage first stops 12a and 13a of right and left gears 12 and 13 to be described later, and engaging extensions 1 Oc and 1 1 c. The right and left gears 12 and 13 are journalled on pivots (not shown) extending perpendicular to the rear surface of the chassis 1. These gears 12 and 13 are partially cut-out gears having teeth 12e and 13e formed along a three quarters of their circumference. The gears are located such that the partially cut-out gears 12 and 13 may mesh with the gears 4b and 5b of the first and second flywheels 4 and 5.It is to be noted that the cut-out gears 12 and 13 are formed with notches extending circumferentially inward from the edges of the toothed portion such that they may be brought in resilient abutment with the capstan gears 4b and 5b to ensure smooth meshing. The cut-out gears 12 and 13 have first stops 12a and 13a, second stops 12b and 13b, and cams 1 2c and 1 3c on the front surface, and third stops 12d and 13d on the rear surface.

Torsion spring 14' and 15' are disposed with their central coiled portions mounted on studs on the chassis 1. One ends of the torsion springs 14' and 15' are engaged with the third stops 12d and 13d on the cut-out gears 12 and 13 while the other ends are engaged with projections 1 Od and 1 1d on the rear surface of the trigger levers 10 and 11. Thus, the torsion springs 14' and 15' act to bias the gear 12 clockwise and the left gear 13 counterclockwise (when viewed in Fig. 2). The torsion springs 14' and 15' functions such that the trigger levers 10 and 11 are biased in a direction to draw the suction rods 8a and 9a out of the solenoids 8 and 9, and the teeth 12e and 13e of the cutout gears 12 and 13 may mesh with the capstan gears 4b and 5b.However, since the claws 1 Ob and 11 b of the trigger levers 10 and 11 are engaged with the first stops 12a and 13a of the cut-out gears 12 and 13, the cut-out gears 12 and 13 at their teeth 12e and 13e do not come in mesh with the capstant gears 4b and 5b.

The arrangement at the rear of the chassis 1 has been illustrated with reference to Figs. 2 and 4. The arrangement in front of the chassis 1 will be illustrated below by referring to Figs. 1 and 3.

Right and left sub-pinch arms 14 and 15, preferably made of a synthetic resin, are mounted on pivots 1 c and 1 d extending perpendicular to the chassis 1. Springs 14d and 15d are also mounted on the pivots 1 c and 1 d such that the sub-pinch arms 14 and 15 are spring biased toward cassette holds 1e and 1f. More specifically, since the springs 14d and 15d are abutted at one end against the cassette holds 1 e and 1 f and at the other end against the sub-pinch arms 14 and 15, the sub-pinch arms 14 and 15 are spring biased such that their abutments 14a and 1 5a contact the cassette holds 1 e and 1 fat the outer wall.The sub-pinch arms 14 and 15 have second abutments 14b and 15b adapted to contact studs 21 b and 21 con a pinch arm drive lever 21 to be described later, and pins 1 4c and 1 sic adapted to contact control springs 18 and 19 disposed within pinch arms 16 and 17. The pinch arms 16 and 17 having pinch rollers 16a and 17a pivoted for free rotation are rotatably mounted on the pivots 1 c and 1 d. The control springs 18 and 1 9 are fitted over the pivots 1 c and 1 d within the pinch arms 16 and 17 and have the both ends engaged with the corresponding pinch arms 16 and 17.

Consequently, the control springs 18 and 19 do not act on the pinch arms 16 and 17. The pinch arms 16 and 17 are provided with windows 16b and 17b through which the end portions of the control springs 18 and 19 are exposed. The sub-pinch arms 14 and 15 are located with respect to the pinch arms 16 and 17 such that the sub-pinch arm pins 1 4c and 1 sic are placed in the pinch arm windows 16b and 17b and engaged with the end portions of the control springs 18 and 19 which extend across the windows.If the sub-pinch arm 14 or 15 is turned about the pivot 1 c or 1 d against the action of the spring 14d or 15d by means of the stud 21 b or 21 c of the pinch arm-drive lever 21, the pinch arm 1 6 or 17 is turned about the same pivot via the pin 1 4c or 1 sic and the control spring 18 or 19 such that the pinch roller 16a or 17a is resiliently brought in pressure contact with the capstan 4a or 5a. After the pinch roller 1 6a or 17a has been in pressure contact with the capstan 4a or 5a, the excessive rotating force of the sub-pinch arm 14 or 15 is absorbed by the control spring 18 or 19.

A connecting plate 20, preferably made of a synthetic resin, has at the rear a pin 20a which is received in a vertically extending guide slog 1 g in the chassis 1. The pin 20a acts as a pivot about which the connecting plate 20 is swung. The connecting plate 20 has at one end a ring 20e with an opening 20b into which a center pivot 21a of the pinch arm-drive lever 21 is inserted.

Further the connecting plate 20 has on the front surface a substantially vertically extending strip 20d having a protruding pin 20c which is received in a slot 25a in a shift lever 25 to be described later. The connecting plate 20 further has on the rear surface a V-shaped channel 20f with which a guide pin 1K embedded in the chassis 1 is engaged. The pinch arm drive lever 21 is pivotally mounted via the engagement of its center pivot 21 a with the opening 20b in the connecting plate 20 so that the forward extending studs 21b and 21 c at the both ends may be selectively engaged with the sub-pinch arm abutments 14b and 15b when the connecting plate 20 is swung to the right or left to move the pinch arm-drive lever 21 in the same direction.

A cam follower 22 has on the rear surface a pin 22a which is also received in the guide slot 1 g in the chassis 1 and on the right and left shoulders control pins 22b and 22c which extend rearward through windows 1 h in the chassis 1 in correspondence with the cams 1 2c and 1 3c of the cut-out gears 12 and 13. The cam follower 22 has on the front surface two studs 22d and 22d which are inserted into openings 23a and 24a in hooks 23 and 24 to be described later, and two arms 22e and 22e which are adapted to engage two tabs 25b and 25b extending rearward from the shift lever 25 to be described later.

The right and left hooks 23 and 24, preferably made of a synthetic resin, have the openings 23a and 24a into which the cam follower studs 22d and 22d are pivotally inserted. The hooks 23 and 24 have at the lower end claws 23b and 24b adapted to engage with the strip 20d on the connecting plate 20, and at the upper end rearward extending pins 23c and 24c for controlling brake levers 37 and 38 to be described later. The hooks 23 and 24 have at the center L-shaped holding ears 23d and 24d on which one ends of springs 26 and 27 rest as described later.

The shift lever 25 has at the both ends channel-defining U-shaped walls which receive guide posts 1 i formed integral with the chassis 1 so that the shift lever 25 may be laterally moved in a sliding manner. As described above, the shift lever 25 is provided with the slot 25a through which the pin 20c on the connecting plate 20 extends, and has the two rearward extending tabs 25b and 25b which correspond to the engaging arms 22e and 22e of the cam follower 22.

The holding springs 26 and 27 are attached to the chassis 1 by the engagement of their coils with support pins formed integral with the chassis as seen from Fig. 1. The springs are engaged at one end with the L-shaped holding ears 23d and 24d of the hooks 23 and 24 and at the other end with the shift lever 25. These holding springs 26 and 27 function to bias the hooks 23 and 24 and hence, the cam follower 22 toward the bottom in Fig. 1 so that the cam follower pins 22b and 22c are normally located adjacent the cams 1 2c and 13c of the cut-out gears 12 and 13.

A head base 28 of an inverted T shape has at the crossing a rearward extending pin 28a received in a guide groove 1j in the chassis 1 and at the top a roller (not shown) adapted to roll on the surface of the chassis 1 so that the head base 28 is movable in the vertical direction. The headbase 28 is also formed with two openings 28c and 28e through which the studs 21b and 21 c of the pinch arm-drive lever 21 extend and with another opening 28b through which the pin 20c of the connecting plate 20 extends. Mounted on the head base 28 is a head assembly including recording/reproducing and erasing heads and their mounts. Specifically, a fixed mount 29 for a recording/reproducing head 33 is secured to the head base 28.Another mount 30 is pivotally mounted on the fixed mount 29 via the pivotal connection between a pin 30a and an opening 29a and has a pair of erasing heads 31 and 32 mounted at the both ends. The recording/reproducing head 33 is interposed between the erasing heads 31,32. The erasing head mount 30 has two projections 30b and 30c which are extended from the rear surface of the mount 30 through openings 29b and 29c in the fixed mount 29 to the position engageable with the studs 21 b and 21 c of the pinch arm drive lever 21. The recording"'reproducing head 33, preferably a rotary head, is rotatably mounted in a guide channel 29d in the fixed mount 29. The recording/reproducing head 33 is provided with a gear 33a at the rear end for the rotation of the head.A segment gear 34 is pivoted to the rear surface of the fixed mount 29 and located in mesh with the gear 33a of the rotary head 33. The segment gear 34 has a pin 34a on the rear surface. A slide plate 35 of an L-shaped crosssection is provided with a laterally extending slot 35a through which the pin 28a of the head base 28 extends. The vertically extending portion of the slide plate 35 is disposed between the head base 28 and the chassis 1 and provided with a recess 35b which is engaged with the ring 20e of the connecting plate 20. The laterally extending portion of the slide plate 35 is provided with a guide channel 35c which is engaged with the segment gear pin 34a.The sliding movement of the slide plate 35 causes the reproducing head 33 to rotate 180 degrees through the engagement of the channel 35c with the pin 34a and the meshing of the segment gear 34 with the gear 33a. It is to be noted that a laterally extending plate 36 is fixedly secured to the chassis 1 at the both ends for holding the head assembly while allowing the movable mount 30 to slidingly move below the plate 36.

A braking mechanism is provided in conjunction with reels. A pair of brake levers 37 and 38 each having a brake shoe secured are pivotted to the chassis 1. One ends of the brake levers 37 and 38 are pulled toward each other by means of a spring such that the brake shoes on the other ends are forced in contact with the rim of the reel bases 44 and 45. The hook 23 or 24 is moved in engagement with the brake lever 37 or 38 to thereby release the corresponding brake shoe from the reel bases.

Attached to an opening 25c in the right end of the shift lever 25 is a switch controlling member 39 which is engaged with a knob of a slide switch 40 (see Fig. 4) for changing the direction of rotation of the reel motors 44 and 45 as well as the capstan motor associated with the flywheel 4.

The structure of the cassette tape recording/reproducing apparatus according to the present invention has been illustrated. The operation of this apparatus will be described below.

Figs. 1 and 3 illustrate the apparatus in the stop position in the forward mode of operation. More particularly, the shift lever 25 is shifted to the right as well as the slide plate 35. In this condition, the strip 20d on the connecting plate 20 is engaged with the claw 23b of the right hook 23, and the right stud 21 b of the pinch arm drive lever 21 is placed in correspondence with the projection 14b of the right sub-pinch arm 14 and the left stud 21 c is placed in correspondence with the left projection 30c of the erasing head mount 30. The rotary head 33 is in a position ready for reproduction in the forward direction.

1. Cue Operation (fast feed reproduction in the forward direction) When the apparatus is loaded with a cassette and a power switch is manually or automatically turned on, the first flywheel 4 begins to rotate. In this condition, a switch for fast forward operation is closed which is electrically connected to the solenoid 8, though it is not shown in the drawings.

The right solenoid 8 is then energized to withdraw the rod 8a to thereby rotate the trigger lever 10 counterclockwise. The trigger lever claw 1 0b is thus disengaged from the first stop 12a of the cut-out gear 12. Since a clockwise rotating force is imparted to the gear 12 by means of the biasing spring 14', this disengagement allows the gear 12 to rotate a small angle and subsequently, at the leading edge of its teeth 12e to come in mesh with the first flywheel gear 4b as shown in Fig. 5. Since the first flywheel 4 is rotating counterclockwise, the gear 12 is rotated clockwise until its first stop 12a abuts against the engaging extension 10c of the trigger lever 10. At this point, the cut-out of the gear 12 faces the first flywheel gear 4b, and thus the first flywheel 4 rotates independent of the gear 12.It is to be noted that a clockwise rotating force is still imparted to the gear 12 by means of the biasing spring 14' at this point.

As the cut-out gear 12 rotates, the cam 1 2c moves in abutment with the right control pin 22b of the cam follower 22 which is guided along the configuration of the cam 1 2c and moved upward as shown in Fig. 6. The cam follower 22 is thus displaced to a slant position with its right shoulder raised. It should be noted that since the right control pin 22b of the cam follower 22 is in abutment with the window 1 h in the chassis 1 and not with the cam 12 prior to the rotation of the gear 12, the gear 12 is initially rotated smoothly. The left shoulder of the cam follower 22 is kept unmovable at that point because the left control pin 22c of the cam follower 22 is in abutment with the second stop 13b on the left gear 13.As the cam follower 22 is displaced to a slant position, the hook 23 which is pivoted on the stud 22d is also moved upward as shown in Fig. 6. Since the claw 23b of the hook 23 is in engagement with the strip 20d on the connecting plate 20, the connecting plate 20 is also moved upward. As a result, the pinch arm-drive lever 21, which is in pivotal connection with the connecting plate 20 through the pivot 21 a and the opening 20b, is also moved upward. Consequently, the left abutment tab 30c of the erasing head mount 30, with which the pin 21 c of the pinch arm-drive lever 21 has been located in alignment, is urged so that the erasing head mount 30 is rotated until its abutment tab 30c abuts against the wall of the opening 29c in the recording/reproducing head mount 29. Consequently, the left erasing head 32 is advanced to the tape path.Furthermore, after the abutment of the tab 30c against the wall of the head mount opening 29c, a further movement of the pinch arm drive lever 21 causes the recording/reproducing head mount 29 to move upward. The head base 28 is also moved upward with the head mount 29. The distance over which the pinch arm-drive lever 21 can move is limited such that the head base 28 is moved to the position where the recording/reproducing head 33b is inserted into the corresponding window in the cassette casing and brought in light contact with the tape.On the other hand, since the pin 21b of the pinch arm-drive lever 21 is placed in correspondence with the abutment 14b of the sub-pinch arm 14, the pinch arm-drive lever 21 causes not only the head base 28 to advance, but also the sub-pinch arm 14 to turn against the action of the spring 14d, thereby moving the pinch roller 16a in close proximity to the capstan 4a as shown in Fig. 6. Furthermore, as the hook 23 is moved upward, the hook 23 at its control pin 23c causes the brake lever 37 to turn about its pivot. The other brake lever 38 is turned together, thereby cancelling the braking action.

The reel motors 44 and 45 start rotating in this condition to thereby feed the tape in the fast forward mode, while the sliding contact of the recording/reproducing head 33b with the tape enables detection of blank intervals between recorded portions or any other head operation.

Fast feed reproduction in the forward direction is thus achieved.

While the command of cue operation continues, the solenoid 8 is kept energized and the first stop 12a on the cut-out gear 12 is in abutment with the engaging extension 10c of the trigger lever 10, which prevents the gear 12 from rotating, thereby maintaining the cue operation.

In the above-mentioned cue operation, if the solenoid 8 is de-energized, the trigger lever 10 is rotated clockwise by the action of the biasing spring 14' to disengage the trigger lever extension 10c from the first stop 12a of the gear 12. As a result of this disengagement, the gear 12 is restored to the initial position by means of the biasing spring 14'. The cam follower 22 which has been moved upward by means of the cam 1 2c is also restored to the initial position.

Accordingly, the apparatus as a whole restores to the initial state.

2. Pause The pause stage is established in the abovementioned cue operation except that the reel motors 44 and 45 are interrupted, and will be understood without further description.

3. Playback Operation From a stage of the above-mentioned cue operation when the reel motors 44 and 45 are interrupted, that is, the pause stage, playback operation will be initiated as follows. A playback button which is electrically connected to the left solenoid 9 and not shown in the drawings is pushed to thereby energize the left solenoid 9.

With the rod 9a withdrawn, the claw 11 b of the left trigger lever 11 is disengaged from the first stop 13a of the left cut-out gear 13. The cut-out gear is counterclockwise rotated a small angle by means of the biasing spring 15' to come in mesh with the gear 5b of the second flywheel 5.

The gear 13 is then forcedly rotated until the first stop 13a abuts against the engaging extension 11 c of the trigger lever 11. With this rotation, the cam 1 3c of the gear 1 3 contacts and moves upward the left control pin 22c of the cam follower 22. The cam follower 22 which has been displaced in a slant manner is thus moved further upward. That is, the cam follower 22 is turned clockwise about a pivot defined by the right control pin 22b in contact with the cam 1 2c of the right gear 12. The cam follower 22 is totally moved to an upper level parallel to the initial position. As a result, the connecting plate 20 is further moved upward as shown in Fig. 7.Since the stud 21b of the pinch arm-drive lever 21 is biased clockwise about the pivot 21 a by a force of a larger magnitude including the force of reaction of the right sub-pinch arm 14 and the weight of the head assembly, the pinch arm-drive lever 21 first urges the head base 28 upward by way of the stud 21 c and the erasing head mount 30. When the head base 28 reaches the predetermined position and is stopped thereat by a stop, the pinch arm-drive lever 21 is further moved upward by means of the connecting plate 20. The subpinch arm 14 is thus rotated clockwise and the pinch arm 16 in resilient connection with the subpinch arm 14 is rotated together.Accordingly, the pinch roller 16a is resiliently brought in pressure contact with the capstan 4a via the tape, By starting rotation of the reel motor 44 in this condition, playback operation is established as shown in Fig. 7.

The excess of the stroke of the pinch arm drive lever 21 is absorbed by the control spring 18 since the pin 1 4c of the sub-pinch arm 14 is in contact with the control spring 18. At the same time, the guide pin 1 k comes in abutment with the left bottom of the V-shaped channel 20f in the connecting plate 20. The movement of the connecting plate 20 is thus restricted both in the vertical and lateral directions. Even if the apparatus undergoes an impact at the abovementioned cue or playback position, the engagement of the guide pin 1k with the Vshaped channel 20f prevents the connecting plate 20 from moving in the lateral direction to disengage the strip 20d from the right hook claw 23b, as seen from Fig. 7.

4. Change of Feed from the Forward to the Reverse Direction If the left solenoid 9 is energized in the stop or initial stage described above, the left trigger lever 11 is rotated counterclockwise to disengage its claw 11 b from the first stop 13a of the left cutout gear 13. This disengagement allows the cutout gear 13 to be rotated a small angle by means of the biasing spring 1 5' and to come in mesh with the gear 5b of the left flywheel 5. Since the right flywheel 4 is rotating at this point, the left flywheel 5 is also rotated by way of the belt 7.

The gear 1 3 is thus rotated counterclockwise.

Since the solenoid 9 is energized only for a while, the trigger lever 11 is restored to the initial position by means of the biasing spring 1 5,. This means that the engaging extension 11 c of the trigger lever 11 is kept out of the path of the first stop 13a of the gear 13 and the gear 13 makes a rotation before it is stopped. As the gear 13 rotates, the cam 1 3c comes in contact with the left control pin 22c of the cam follower 22 and urges upward the pin 22c which follows the configuration of the cam. Since the right control pin 22b is in abutment with the second stop 12b of the right gear 12, the cam follower 22 is rotated about the right control pin 22b.When the cam follower 22 is displaced in a slant manner with its left shoulder raised, the right arm 22e is brought in contact with the right tab 25b of the shift lever 25 to slide the shift lever 25 to the left.

Since the pin 20c of the connecting plate 20 is fit in the slot 25a in the shift lever 25, the leftward movement of the shift lever 25 causes the connecting plate 20 to swing clockwise about the pin 20a. In response to the leftward movement of the shift lever 25, the switch 40 is changed into another condition by way of the switch control member 39 attached to the shift lever 25 at 25c, to thereby generate a signal representative of changing to the reverse direction to the control circuit.

Further, the leftward movement of the ring 20e of the connecting plate 20 causes the slide plate 35 to move to the left. Since the pin 34a of the segment gear 34 is in engagement with the guide channel 35 in the slide plate 35, the leftward movement of the slide plate 35 causes the segment gear 34 to rotate and hence, the rotary head 33 to rotate an angle of 180 degrees, thereby setting the recording/reproducing head 33b ready for operation in the reverse direction.

Once the rotary head 33 is rotated, it is oppositely biased by a well-known biasing means and restricted for the stop position by means of an azimuth adjustment mechanism both of which are not shown in the drawings.

When the cut-out gear 13 has made a rotation, the cam follower 22 is restored to the initial position. Reversal of feed direction is thus accomplished as shown in Fig. 8.

During the reversing operation described above, although the hook 24 is moved upward, the claw 24b of the hook 24 is out of engagement with the strip 20d on the connecting plate 20 because the connecting plate 20 has not yet been moved to the left. The likelihood of advancing the head base 28 is thus avoided.

The reversing operation is accomplished as above. Although the reversing operation is independently performed in the above-illustrated embodiment, the reversing operation may be initiated during the playback operation in the reverse direction to thereby change the apparatus into the playback operation in the forward direction.

The review operation (that is, fast feed reproduction in the reverse direction), pause and playback operation in the reverse direction will be readily understood by those skilled in the art because these operations are performed in a symmetrical relationship to the operations in the forward direction.

In a drop impact test, the apparatus of the above described structure is dropped upside down. The suction rods 8a and 9a are then withdrawn into the solenoids 8 and 9 due to their own weight to turn the trigger levers 10 and 11 to disengage their claws 1 Ob and 11 b from the first stops 12a and 1 3a of the cut-out gears 12 and 13. The biasing springs 14' and 15' apply a sufficient force to the cut-out gears 12 and 13 to move them in mesh with the flywheel gears 4b and 5b.

The cam follower 22 is, however, moved upward at this point as shown by dot-and-dash lines in Fig. 9 because the apparatus is placed upside down. More specifically, since the cam follower 22 is mechanically coupled with the head base 28 and other members associated therewith, the cam follower 22 is moved upward with them in the drawing due to the drop impact. With the cam follower 22 moved upward, the cam follower pins 22b and 22c abut against the second stops 12b and 13b of the cut-out gears 12 and 13 to preclude rotation of the gears 12 and 13. After the impact disappears, the solenoid rods 8a and 9a are again protruded by the action of the biasing springs 14' and 15' to restore the trigger levers. 10and 11 to the initial position where the trigger lever claws 1 Ob and 11 b are in engagement with the cut-out gear first stops 12a and 13a.All the members are thus restored to the initial position. Even after the apparatus has experienced impact due to a drop test or during commercial conveyance, the apparatus is precluded from starting operation immediately after the power source is connected.

Such a problem does not occur when an impact is imposed on the apparatus placed in the normal position, because the solenoid rods 8a and 9a are not withdrawn.

For the purpose of protecting the apparatus from being affected by impact in a drop impact test or during conveyance, the cut-out gears 12 and 13 may be provided with counter weights instead of using the engagement of the cam follower pins with the cut-out gear second stops.

These counter weights are designated at 12f and 13f in Fig. 2. When Fig. 2 is viewed upside down, it will be understood that the counter weights 12f and 1 3f act oppositely to the biasing force of the springs 14' and 15'. Since the gravitational force due to the counter weights 12f and 13f are equal to or larger than the biasing force of the springs 14' and 15', the cut-out gears 12 and 13 are prevented from rotating when the trigger lever claws 1 Ob and 11 b are disengaged from the cutout gear first stops 12a and 1 3a.

For the purpose of restricting the movement of the connecting plate 20, the chassis 1 and the connecting plate 20 are provided with the guide pin 1 k and the V-shaped channel 20f, respectively, in the above-illustrated embodiment.

Of course, the chassis may be provided with a guide pin and the connecting plate may be provided with a guide pin. Furthermore, instead of the connecting plate 20 provided with a guide pin or V-shaped channel, any member which moves in cooperation with the connecting plate in the lateral direction upon rotation of the head and in the vertical direction in the cue or playback operation, that is, the slide plate or pinch armdrive lever may be provided with a guide pin or Vshaped channel.

Although the present invention is illustrated in the above embodiment as being applied to the double-capstan system, the concept of the present invention may also be applied to the dualcapstan closed loop system in which the capstans are rotated in the same direction and contacted with the pinch rollers at the same time.

Claims

1. In a cassette tape recording/reproducing apparatus comprising a head base having a recording/reproducing head and a pair of erasing heads mounted thereon and being movable among the stop, intermediate and playback positions, a pair of capstans adapted to rotate in given directions, and a pair of pinch arms each having a pinch roller pivotally mounted, the erasing heads, capstans and pinch rollers in pairs being arranged symmetrically with respect to the recording/reproducing head, a drive mechanism comprising a pair of cams adapted to be independently driven in response to the selected mode of operation of the apparatus, a cam follower having at both ends two control pins disposed to engage with said cams when the cams rotate, said cam follower being displaceable by the rotation of one or both of said cams, and means for moving the head base back and forth in response to any displacement of said cam follower, whereby the head base is moved to the intermediate position in response to a slant displacement of said cam follower caused by the rotation of either of said cams, and the head base is advanced to the playback position in response to a parallel displacement of said cam follower caused by the rotation of both of said cams.

2. A drive mechanism according to claim 1 which further comprises, for each of said cams, a partially cut-out gear coaxially attached to said cam and adapted to mesh with a capstan gear on the capstan, said cut-out gear at the cutout portion normally facing the capstan gear, a solenoid adapted to be energized in response to the selected mode of operation of the apparatus, a trigger lever linked at one end with said solenoid and releasably engaged at another end with said cut-out gear, and a biasing spring engaged at one end with said gear to apply a sufficient rotational force to said cut-out gear to bring the cut-out gear in mesh with the capstan gear, whereby said trigger lever is withdrawn upon energization of said solenoid to thereby release the other end of said trigger lever from said cutout gear, and said cut-out gear is thus brought in mesh with the capstan gear by the action of said biasing spring, thereby rotating said cam.

3. A drive mechanism according to claim 2 wherein said biasing spring is engaged at the other end with said trigger lever to bias said trigger lever in a direction opposite to the withdrawal by said solenoid.

4. A drive mechanism according to claim 2 which further includes means for limiting the stroke over which said cam follower is displaced such that the control pins of said cam follower are not in contact with said cams when the apparatus is in the stop position.

5. A drive mechanism according to claim 2 wherein said cut-out gear includes safety means for preventing said cut-out gear from rotating by the rotational force applied thereto by the biasing spring when an external impact is accidentally applied to the apparatus placed upside down to release the trigger lever from said cut-out gear.

6. A drive mechanism according to claim 5 wherein said safety means is a stop provided on said cut-out gear and disposed adjacent the control pin of said cam follower when said cut-out gear at the cut-out portion faces the capstan gear, whereby the control pin of said cam follower is engaged with the stop on said cut-out gear to prevent said cut-out gear from rotating when an external impact is applied to the apparatus placed upside down to release the trigger lever from said cut-out gear.

7. A drive mechanism according to claim 5 wherein said safety means is a counter weight provided on said cut-out gear and disposed to act to overcome the rotational force applied by the biasing spring to said cut-out gear when the apparatus is placed upside down, whereby said counter weight prevents said cut-out gear from rotating when an external impact is applied to the apparatus placed upside down to release the trigger lever from said cut-out gear.

8. A drive mechanism according to claim 1 which further comprises selective means operatively connected to said cam follower and to said pinch arms for selecting one of said pinch arms in response to a slant displacement of said cam follower caused by the rotation of either of said cams.

9. A drive mechanism according to claim 8 wherein said head base moving means and said selective means are mechanically coupled whereby the head base is moved to the intermediate position and one of the pinch arms is selected in response to a slant displacement of said cam follower, and the head base is advanced to the playback position and the pinch roller of the selected pinch arm is brought in pressure contact with the corresponding capstan in response to a parallel displacement of said cam follower.

10. A drive mechanism according to claim 9 wherein said selective means and said head base moving means are mechanically coupled and include the cam follower, a pair of hooks pivotally connected to said cam follower, a connecting plate having a strip attached thereto and swingable between locations allowing said strip to be engaged by said hooks in response to a slant displacement of said cam follower, whereby the slant displacement of said cam follower causes not only said connecting plate to swing to the location allowing strip-hook engagement, but also either of said hooks to advance, thereby advancing said connecting plate.

11. A drive mechanism according to claim 10 wherein said selective means and said head base moving means further include a shift lever which is slidable in a direction parallel to the direction connecting the pinch arms, engageable with either end of said cam follower, and loosely connected to said connecting plate, whereby the slant displacement of said cam follower causes said shift lever to slide to thereby swing said connecting plate.

12. A drive mechanism according to claim 10 wherein said selective means further include a pinch arm-drive lever pivotally connected at the center to said connecting plate and engageable at the end with either of said pinch arms when said connecting plate is swung to one location, wherein said connecting plate and said pinch arm-drive lever cooperate to bring the selected pinch roller in pressure contact with the corresponding capstan.

13. A drive mechanism according to claim 12 wherein said pinch arm has a spring mounted therein, and said pinch arm-drive lever urges said pinch arm through said spring to thereby resiliently contact the pinch roller with the capstan.

14. A drive mechanism according to claim 10 wherein said connecting plate and a fixed member of the apparatus are provided with a guide pin and a V-shaped channel, thereby preventing the connecting plate from moving under any external forces, but allowing the connecting plate to swing in response to any displacement of the cam follower.

15. A drive mechanism according to claim 10 wherein the recordingireproducing head is a rotary head rotatably mounted on the head base, and the drive mechanism further includes means for rotating the rotary head over an angle of 180 degrees.

16. A drive mechanism according to claim 15 wherein said rotating means comprises a slide plate slidably disposed parallel and adjacent to the head base and engaged with the connecting plate, a segment gear having a pin engaged with said slide plate, and a head gear coaxially attached to the rotary head and disposed in mesh with said segment gear, whereby said connecting plate is swung to one or the other location in response to a slant displacement of said cam follower to slide said slide plate to rotate said segment gear, thereby rotating the head gear over an angle of 180 degrees.

17. A drive mechanism according to claim 1 wherein the recording/reproducing head is mounted on the head base, a movable head mount having the two erasing heads mounted thereon is pivotally connected to the head base such that the recording/reproducing head is disposed intermediate the erasing heads, and said head base moving means includes a connecting plate operatively connected to the cam follower and to the movable head mount for advancing the head base and pivotally moving said movable head mount to advance one of the erasing heads in correspondence with the selected mode of operation of the apparatus.

18. A drive mechanism according to claim 17 wherein said head base moving means further includes a pinch arm-drive lever having both ends, pivotally connected to said connecting plate, and movable between two locations in response to a slant displacement of said cam follower through said connecting plate, whereby the one and other end of said pinch arm-drive lever are located in correspondence with one of the pinch arms and the opposite one of the erasing heads, respectively, when said pinch arm-drive lever is moved to one location.

19. A drive mechanism according to claim 1 wherein the recording/reproducing head is a rotary head rotatably mounted on the head base, a movable head mount having the two erasing heads mounted thereon is pivotally connected to the head base such that the rotary head is disposed intermediate the erasing heads, said head base moving means including a connecting plate operatively connected to said cam follower and to said movable head mount for advancing the head base and pivotally moving said movable head mount to advance one of the erasing heads in correspondence with the selected mode of operation of the apparatus, the drive mechanism further includes means for rotating the rotary head, said rotating means including a slide plate slidably disposed parallel and adjacent to the head base and engaged with the connecting plate, a segment gear having a pin engaged with said slide plate, and a head gear coaxially attached to the rotary head and disposed in mesh with said segment gear, whereby in response to a slant displacement of said cam follower, said connecting plate is moved in one direction to move the head base to the intermediate position and concurrently moved in another direction perpendicular to said one direction, thereby pivotally moving the movable head mount to select one of the erasing heads as well as sliding said slide plate to rotate said segment gear to rotate the rotary head over an angle of 180 degrees.

20. A drive mechanism for cassette tap recording/reproducing apparatus substantially as hereinbefore described with reference to the accompanying drawings.