JPH0786990B2 - Treading mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a tape loading mechanism suitable for use in a small VTR such as an 8 mm video.

(B) Conventional technology In recent years, the miniaturization of VTRs has progressed, and a new standard compact VTR called 8 mm video has been developed. A so-called reverse U is used as a tape loading mechanism for this 8 mm video.
The loading method is advantageous for downsizing. This reverse U-loading method is known from JP-A-57-86161 and the like, and basically, the tape is pulled out from the cassette in an oblique direction with respect to the cassette mounting surface and mounted on the guide cylinder with the tape inclined. The first loading means, the second loading means for pulling out the tape from the cassette in parallel with the mounting surface, and the tape driving means moved together with the second loading means.

In this conventional example, the block in which the leading guide pin is arranged is guided in the guide groove of the guide member with a relatively large backlash, and at the end thereof, it is only pressed by the urging force of the spring, so that The positioning accuracy in the tilt direction is not very high.

However, the tape traveling system of 8 mm video for the purpose of downsizing and high density recording requires higher precision.

(C) Object of the invention The present invention has been made in view of the above points, and proposes a highly accurate tape loading mechanism that can be used even for 8 mm video.

(D) Configuration of the Invention The present invention is a tape loading mechanism in which a tape is moved from a cassette by a tape guide that is moved along a predetermined moving path and is wound around a guide cylinder in a spiral shape. A moving body to be placed, a positioning pin provided on the moving body, a guide member for guiding the moving body along a moving path inclined with respect to the mounting surface of the cassette, and a driving means for driving the moving body. When the movable body comes to a position just before the loading completion position, one end of the positioning pin abuts and the driving means is further driven, so that one side of the positioning pin 1 abuts. And a fixing block having a second fixing surface with which one side surface of the moving body abuts, a tape loading mechanism.

(E) Example An example in which the present invention is applied to an 8 mm video will be described below with reference to the drawings.

The loading mechanism of this embodiment basically adopts a new U loading mechanism for 8 mm video, and is roughly classified into a first loading mechanism, a second loading mechanism, and a back tension lever withdrawing mechanism.

First, the first loading mechanism will be described with reference to FIGS. 1 to 5 and 8.

( 1 ) is a cassette, and the tape (2) is mounted between the supply reel (1a) and the take-up reel (1b), and is cut out in front (1).
c) has been formed. The cassette ( 1 ) can be moved up and down by a cassette holder (not shown).

( 3 ) is a guide cylinder that incorporates a rotary head (not shown), and this guide cylinder ( 3 ) is composed of a rotary upper cylinder (3a) and a fixed lower cylinder (3b).

( 4 ) is an annular loading disc rotatably arranged around the guide cylinder, and a gear portion (4a) is formed on the outer periphery thereof. (5) is a joint whose one end is joined on this loading disc,
It is rotatable in the vertical direction and is biased in the extension direction by a coil spring. The structure itself of this joint is well known.

Reference numeral ( 6 ) is a bracket connected to the other end of the joint, and the bracket is supported by a bracket guide body ( 7 ) provided on the outer circumference of the loading disk over about 270 °. That is, as shown in FIG. 4, the bracket ( 6 ) engages with the guide groove (7a) formed in the inner periphery of the bracket guide body ( 7 ) by its convex portion (6a) and the bent piece (6b). It is movably supported by engaging the upper surface and the outer side of the bracket guide body ( 7 ).

(8) is a leading guide pin that is erected on the bracket, (9) and (10) are also erected on the bracket, and the folded tape (4) keeps the first and second tapes in contact with each other. It is the second guide pin. Reference numeral ( 11 ) is a projecting pin projecting below the leading guide pin, and engages with a recess (12a) of the first fixing block ( 12 ) arranged on the side of the lower guide cylinder at the loading completion position. To do.

Reference numeral (13) is a full width erasing head arranged on the tape running path between the supply reel (1a) and the guide cylinder ( 3 ) and is fixed on the head support plate (14).

(15) is a back tension lever having a tension detection pin (16) at its tip, and a support shaft (17) is rotatably supported and driven by a back tension lever withdrawing mechanism described later.

Further, reference numeral (18) is a taper guide pin for winding the tape (2) drawn out from the supply reel in the horizontal direction on the guide cylinder ( 3 ) in a tilted state, and a taper having an inverted conical shape is formed. ing. Each of (19) and (20) is a winding angle defining pin that regulates the winding angle of the tape (2) with respect to the guide cylinder ( 3 ) to about 210 °.

Next, regarding the second loading mechanism, the first, second and sixth
And it demonstrates according to FIG.

Reference numeral (21) is a pinch roller that presses the capstan (22) to make the tape (2) run at a low speed, and is mounted on a pinch roller lever (24) pivotally supported by a support shaft (23). The support shaft (23) is supported on the first slide member ( 25 ). (26) is a tape pull-out pin arranged on the first slide member. A second slide member ( 27 ) is arranged below the first slide member ( 25 ). The first slide member ( 25 ) has a through hole (25a),
Into the through hole (25a), a loose fitting pin (27a) that is erected on the second slide member is loosely fitted. Then, the loose fitting pin (27a) and the tip of the first slide member ( 25 ) are cut and raised (25
A spring (28) is stretched between it and b), and both slide members are integrated. Further, a gear portion (27b) is formed on one side of the second slide member, and the gear portion (27b) meshes with a reduction gear (30) that meshes with a loading gear (29) coupled to a loading motor (not shown). Meshes with. Incidentally, the loading gear gear portion of the loading disc (4) loading the disk are also in mesh with (4a) (4) and the second slide member (27) are driven synchronously.

Further, both sides of the second slide member ( 27 ) are sandwiched by U-shaped guide members (31) ( 32 ) as shown in FIG. A pinch roller guide (32a) for engaging and guiding the end portion of the pinch roller lever is integrally formed of resin on one ( 32 ) of the guide members. This pinch roller guide (32a)
The reason for providing is that the pinch roller lever (24) is biased counterclockwise in FIG. 1 by a torsion spring (not shown), so that the notch (1c) end of the cassette ( 1 ) is loaded at the time of loading. This is to prevent the pinch roller (21) from hitting.

Reference numeral (33) is a second fixing block which is fixed in position by the tips of the first and second slide members entering when the loading is completed.

Further, (34) is a pinch roller crimping lever pivotally supported by the support shaft (35), and (36) is a crimping guide provided at the rotating end of the pinch roller crimping lever. By the play operation, the end of the pinch roller lever (24) and the flange (37) arranged on the upper part of the pinch roller (21) are pressed to press the pinch roller (21) to the capstan (22).

The pinch roller pressure lever is a solenoid (not shown).
However, since the mechanism is well known in the art, the description thereof will be omitted.

Further, the crimping guide also functions as a tape guide when the pinch roller is not crimped and when it is crimped.

That is, the tape (2) passed between the pinch roller (21) and the capstan (22) is the tape pull-out pin (26).
Also, the tape is guided by the crimping guide (36) and wound on the take-up reel (1b) of the cassette ( 1 ). Here, since the cassette for 8 mm video does not have a tape guide inside the cassette for downsizing, if the winding diameter of the take-up reel changes, it may hit the side wall of the tape entrance of the cassette.
Therefore, some kind of tape guide is required to prevent the tape from hitting the tape entrance of the cassette even if the winding diameter changes. The crimp guide (36) functions as this tape guide.

Since the supply reel side also has the problem, a fixed guide pin (38) having the same function as that of the pressure guide (36) is set up on the head support plate (14).

Next, regarding the back tension lever withdrawal mechanism,
It will be described with reference to FIGS. A first gear (39) is coaxially arranged on a support shaft (17) of the back tension lever (15), and the first gear (39) is fan-shaped gear (41) pivotally supported by the support shaft (40). ) Is engaged. This fan gear ( 41 )
The other end of the brake band (42), one end of which is wound around a take-up reel stand (not shown), is connected to the upper part of the fan gear ( 41 ) in the clockwise direction, that is, the back tension lever (15). A spring (43) for biasing the tape (2) by biasing it in the counterclockwise direction is connected to the chassis. Further engagement pins on fan gear (41) (41
a) is arranged, and the engagement pin (41a) is engaged with the cam groove (44a) of the second gear ( 44 ). The end of this cam groove is wider than the other parts, and the engagement pin is allowed to move a predetermined amount in the cam groove at the loading completion position in FIG. 8B.

Reference numeral (45) is a third gear meshing with the second gear, and a fourth gear (46) is arranged coaxially with the third gear.
The gear meshes with the gear portion (4a) of the loading disc.

Therefore, the back tension lever (15) is interlocked with the rotation of the loading disk ( 4 ) and is pulled out together with the tape (2) from the position shown in FIG.

The operation of the back tension mechanism itself in the loading completed state is well known.

Next, the operations of the first and second loading mechanisms and the back tension lever withdrawing mechanism will be described.

First, as shown in FIG. 1, when the cassette (1) is inserted into a cassette holder (not shown) and lowered to the mounting position, the loading motor (not shown) is energized and the loading gear (29) moves counterclockwise. Rotate.

By this rotation, the loading disk ( 4 ) is driven clockwise, and the bracket ( 6 ) is driven through the joint (5) as shown in FIG. 2, so that the leading guide pin (8) pulls out the tape (2). Wrap it around the guide cylinder ( 3 ) together with. At this time, the bracket ( 6 ) is guided by a bracket guide ( 7 ) along a predetermined path, and when it reaches near the end, as shown in FIG. 5 (a), the tip of the projecting pin (11) causes the first fixing block (11). 12 ) recess (12a)
A part of. In this state, the protruding pin (11)
Is not parallel to the side wall of the recess (12a), but as the loading disk ( 4 ) is driven further, the protruding pin (11) becomes parallel to the side wall of the recess (12a) as shown in FIG. Become. The backlash against the convex portion of the bracket the inclination angle (6) Bracket before crimping although Hen' the front crimping (6) In this crimped state (6a) guide grooves of the bracket guide member (7) (7a) Since it is held and engaged, the bracket can be displaced within the range of this play. As a result, as shown in FIG. 5B, the bottom surface of the bracket ( 6 ) is in contact with the upper surface of the first fixing block ( 12 ).

On the other hand, when the loading gear rotates counterclockwise, the second slide member ( 27 ) is moved to the first slide member ( 25 ).
It slides in the upper right direction in FIG. This slide causes the tape pull-out pin (26) as shown in FIG.
Pulls out the tape (2) in the upper right direction.

At this time, the both slide members are guided by the guide members (31) ( 3
2 ) and the pinch roller lever (24) is guided by the pinch roller guide (32a), the pinch roller lever (24) and the pinch roller (21) are notched () in the cassette ( 1 ) during sliding. 1c) It does not touch the end.

In addition, after the pinch roller (21) escapes from the cassette notch (1c) during loading, the pinch roller lever (24)
Is separated from the pinch roller guide (32a), the lever is engaged with the base of the tape pull-out pin (26) to regulate the rotation, and when loading is completed, the pinch roller (21) is capped at a predetermined interval. Opposite Stan (22).

Then, the first slide member ( 25 ) enters the recess (33a) of the second fixed block ( 33 ), and its tip comes into contact with the inner wall and stops. Further, by driving the loading gear (29), the second slide member ( 27 ) enters the recess. At this time, an inclined portion (33b) is formed on the lower surface of the concave portion (33a), and the tip of the second slide member ( 27 ) is guided by the inclined portion (33b) and further invades. Therefore, the sixth
As shown in Fig. (A), the tip of the second slide member ( 27 ) is pushed up and down on the lower surface of the first slide member ( 25 ) to form the recess (33
a) The first slide member ( 25 ) is pressed against the upper surface and the tip of the first slide member ( 25 ) is pressed against the inner wall of the recess (33a) by the urging force of the spring (28). It is positioned without play against 33 ).

On the other hand, the back tension lever (15) is pulled out from the state of FIG. 1 to the position of FIG. 2 by the back tension lever withdrawing mechanism shown in FIG.

That is, as shown in FIG. 8 (a), the clockwise rotation of the loading disc ( 4 ) causes the second gear ( 44 ) to rotate clockwise through the third and fourth gears (45) (46). Turn to. Therefore, the diameter of the cam groove (44a) gradually decreases, and the fan gear ( 41 ) is rotated clockwise by the engagement pin (41a) and the back tension lever (15) is rotated.
Rotates counterclockwise, and the tension detection pin (16) pulls out the tape (2).

Then, as shown in FIG. 8B, when the loading is completed, the engaging pin (41a) is positioned at the end of the cam groove (44a), but the end of the cam groove (44a) is wider than other parts. Since it is wide, the engagement pin (41a) is movable within that range.

That is, the back tension lever (15) is rotatable within a predetermined range.

When the loading is completed as described above, the tape (2) is wound around the guide cylinder ( 3 ) by about 210 ° and the stop mode is set.

In this stop mode, when a play operation is performed, a pinch roller crimping solenoid (not shown) is energized to rotate the pinch roller crimping lever (34) clockwise as shown in FIGS. 2 and 7. Move. By this rotation, the upper and lower ends of the crimping guide (36) press the flange (37) and the pinch roller lever (24), respectively, and the pinch roller (21).
Is crimped onto the capstan (22).

The position of the crimping guide will change slightly depending on whether the pinch roller is crimped or not, but the tape (2) does not come into contact with the tape entrance of the cassette ( 1 ) at any position. There is.

(F) Effect of the Invention As described above, according to the present invention, since the leading guide pin is positioned with extremely high accuracy at the loading completion position, the tape cannot be attached to the tape winding angle defining pin on the guide cylinder. It is possible to realize a high-precision tape running system even when used for 8 mm video without applying any force or twisting.

[Brief description of drawings]

The drawings are all related to one embodiment of the present invention, and FIG. 1 is a plan view of the loading mechanism in an unloading state,
FIG. 2 is a plan view of the same loading completed state, FIG.
FIG. 4 is a perspective view of the first loading mechanism, FIG. 4 is a cross-sectional view of the bracket guide body, FIGS. 5 (a) and (b) are side views of the bracket before and after crimping, and FIG. )
8B is a side view and a front view of the second loading mechanism, FIG. 7 is a perspective view of the pinch roller crimping mechanism, and FIG. 8A is a front view of the back tension lever withdrawing mechanism. FIG. 3 is a plan view after drawing out. Description of main drawing numbers ( 1 ) …… cassette, (2) …… tape, ( 3 ) …… guide cylinder, ( 4 ) …… loading disk,
( 6 ) …… Bracket, ( 7 ) …… Bracket guide,
(8) …… Leading guide pin, (11) …… Projecting pin, ( 1
2 ) …… First fixed block,

Claims (1)

[Claims] 1. A tape loading mechanism in which a tape is pulled out from a cassette by a leading guide that is moved along a predetermined movement path and is wound around a guide cylinder circumferential surface in a spiral shape. A plurality of tapes including the leading guide are provided. A plate-shaped moving body having a guide placed on the upper surface, a positioning pin protruding from the bottom surface so that the side surface is orthogonal to the bottom surface of the moving body, and the moving body having an arc shape with respect to the mounting surface of the cassette. A guide member that guides along a moving path that is inclined, a loading member that moves by the driving force of a driving source, and an elastic member that constantly urges the moving body in the tape loading direction with respect to the loading member. A connecting member for connecting the loading member and the moving body so as to interlock the moving body with the loading member; When it reaches completion position,
A first fixing surface with which the side surface of the positioning pin abuts, and a second contact surface with which the bottom surface of the moving body abuts perpendicularly to the first fixing surface.
A tape loading mechanism comprising a fixed block serving as a fixed surface.