JPH087900B2 - Pinch roller pressure welding mechanism - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a pinch roller pressure contact mechanism for a magnetic recorder / reproducer such as a tape recorder or a VTR.

[Prior Art] FIGS. 12 to 14 relate to a conventional pinch roller pressure contact mechanism disclosed in, for example, JP-A-01-180051.
In the figure, 11 is a capstan shaft, 20 is a cam member that is rotatably supported with a tooth profile formed on its outer peripheral portion, 31 is a cam groove formed in this cam member 20, and 32 is a pin 33 that stands on the chassis. This cam lever 32 is a cam lever pivotally supported by
The pin 34 erected on the above is engaged with the cam groove 31. 3
Reference numerals 5 and 36 are links rotatably joined by a pin 37, and the pin 37 is engaged with an elongated hole 32a formed in the cam lever 32. 38 is a slide lever, 39 is a spring for urging the slide lever in the downward direction in the drawing, and the slide lever 38 has the above-mentioned link 36.
A pin 40 is provided to be connected to the pin 40. Reference numeral 41 is a pin erected on the chassis, 42 is a pinch roller lever pivotally supported by the pin, and 17 is a pinch roller pivotally supported by the pinch roller lever 42. 43 is a pin connecting the pinch roller lever 42 and the link 36.

Next, the operation will be described. FIG. 12 shows the unloading state of the magnetic tape or the like, but the cam member 20 is in the rotational position rotated most counterclockwise by the external driving force, and the cam groove 31 with which the pin 34 is engaged is Nearest to the inner circumference. Therefore, the cam lever 32 is located at the most clockwise position in the figure, and the pinch roller 17 is located away from the capstan shaft 11 as shown by the engagement relationship between the links 35 and 36 and the pinch roller lever 42. .
In this state, since no external force is applied to the pinch roller 17, the slide lever 38 is held at the position closest to the A direction in the figure by the action of the spring 39.

When the loading operation is started, the cam member 20 rotates clockwise and the cam lever 32 starts rotating counterclockwise.
Since no external force is applied to the pinch roller 17, the slide lever 38 does not move, the pin 40 serves as a fixing pin on the chassis, and the link action of the links 35, 36 and the pinch roller lever 42 is shown in FIG. In this way, the pinch roller 17 is moved to a position where it comes into contact with the capstan shaft 11.

When the cam member 20 further rotates clockwise, the cam lever
32 further rotates clockwise. Since the pin 34 engages with the outermost peripheral portion of the cam groove 31, the cam lever 32 rotates most counterclockwise. Since the pinch roller 17 is already in contact with the capstan shaft 11 and the pinch roller lever 42 cannot rotate, the link 35 and the link 36 form a toggle mechanism, and the slide lever 38 is attached with the spring 39. It moves in the direction of B in the figure against the power. Pinch roller lever 42 is pin 43
The load of the spring 39 is received by the slide lever 35 in the direction of B in the figure at, and the moment around the pin 41 causes the pinch roller 17 to move.
Is pressed against the capstan shaft 11 to be in the state shown in FIG. At this time, the load by which the cam lever 32 pushes the pin 37 in the direction C in the figure can be a small value due to the configuration of the state toggle mechanism. That is, at least the driving force for rotationally driving the cam member 20 can obtain a strong pressure contact action of the pinch roller 17.

[Problems to be Solved by the Invention]

However, 4 to 5 links are required from the pin 34 that engages with the cam groove 31 of the cam member 20 to the pinch roller lever 42, and the number of parts is large, and the parts cost and assembly cost are high. was there. Furthermore, due to the large number of parts, there is also a problem in reliability of operation, and even when the state of FIG. 12 shifts to the state of FIG. 13, slidability of the link 35, the link 36, the cam lever 32, etc. is poor, If a load is applied to this portion, the rotation of the pinch roller lever 42 may stop at the middle position of the movement, and at the same time, the slide lever 38 may start moving, which may cause the mechanical operation to be easily changed.

The present invention has been made to solve the above-mentioned problems, and it is possible to obtain a highly reliable pinch roller pressure contact mechanism with a small driving force while reducing the number of parts, the cost of parts and the assembly cost. With the goal.

[Means for solving the problem]

The pinch roller pressing mechanism according to the present invention has a pinch roller arm that supports the pinch roller so that it can be freely attached to and detached from the capstan shaft, and has a predetermined inclined portion at one end and is stretched over the pinch roller arm. A pinch roller urging member,
A cam member that operates by a drive source such as an electric motor in either a first direction that brings the pinch roller closer to the capstan shaft or a second direction that separates the pinch roller from the capstan shaft; and a first direction. A cam member that moves in contact with the inclined portion in response to the cam member that moves in the second direction, and an engagement member that moves away from the inclined portion in response to the cam member that operates in the second direction. Then, the inclined portion is configured such that an angle formed by the inclined portion and the moving direction of the engaging member in contact with the inclined portion is 45 ° or less, and the inclined portion is formed when the cam member operates in the first direction. Is applied from the engaging member in the moving direction of the engaging member to cause a force in a direction perpendicular to the inclined portion to act on the inclined portion to deform the pinch roller urging member, and the deformed pinch roller urging member. The elastic restoring force of the pinch roller is pressed against the capstan shaft.

[Action]

In the pinch roller pressure contact mechanism according to the present invention, the inclined portion is configured such that the angle θ formed by the inclined portion and the moving direction of the engaging member that is in contact with the inclined portion of the pinch roller urging member is 45 ° or less. are doing. Therefore, when the cam member operates in the first direction and the engaging member abuts the inclined portion, the inclined portion receives the acting force of the magnitude F3 in the engaging member moving direction from the engaging member. This acting force F3 has an angle θ with respect to the inclined portion.
Since the force is in the direction of, the force of magnitude F1 (= F3 / sin θ) acts on the inclined portion in the direction perpendicular to the inclined portion. By the way, since θ ≦ 45 °, And F1 ≧ F3 × 1.414. Therefore, even if the driving force of the cam member is small and the acting force F3 applied to the inclined portion by the engaging member is small, a large force F1 in the direction perpendicular to the inclined portion can be generated. A large pressure contact force can be applied by the pinch roller.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1 to 7, 1 is a chassis, 2 is a rotary head drum, 3 is a tape cassette, 4 is a magnetic tape housed in the tape cassette 3, and 5 and 6 are a pair formed on the chassis 1. Groove portions, 7 and 8 are a pair of guide post members that engage with the groove portions 5 and 6, respectively, and 9 and 10 are fixed to the chassis 1, and the guide post members 7 and 8 in the loading state.
Is a guide stopper that prevents the movement of the. Reference numeral 11 is a capstan shaft, and 12 is a flywheel coaxially fixed to the capstan shaft. A driving force is transmitted by a belt 14 between the capstan shaft and the capstan motor 13. Reference numeral 15 is a pinch roller arm supported by a pin 16 standing upright on the chassis 1, 17 is a pinch roller pivotally supported by the pinch roller arm, and 18 is a pinch roller arm.
A pinch roller urging member composed of a torsion spring urged to urge between the abutting portions 15a, 15b of 15 in a direction of expanding,
Reference numeral 19 denotes a pinch roller arm return member including a tension spring or the like for urging the pinch roller arm 15 counterclockwise in the figure.

Reference numeral 20 denotes a cam member pivotally supported on the back surface of the chassis 1, and a tooth profile is formed on the outer peripheral portion of the cam member 20.
Are in mesh with each other. 22 is a loading motor, 23 is a belt hung between the loading motor 22 and the shaft 24, 25 is a worm pressed into the shaft 24, 26 is a wheel, and a gear 27 is fixed coaxially with the wheel 26.
Meshes with the gear 21.

28 is a pin erected on the chassis 1, 29 is an arm pivotally supported by the pin, and 30 is a pin press-fitted into this arm 29. As shown in FIG. The engaging member 30a of the above protrudes, and the lower pin portion 30b protrudes on the back surface side. The lower pin portion 30b penetrates the elongated hole 1a formed in the chassis 1 and engages with the cam groove 31 formed in the cam member 20. FIG. 6 is a view showing the shape of the cam groove 31 in detail, and 31a is a concentric circle portion on the outermost periphery, which corresponds to each rotation α1. Reference numeral 31b denotes a first movement path in which the radius of rotation decreases as the cam member 20 rotates, and corresponds to the rotation angle α2.
Similarly to 31b, 31c also corresponds to the rotation angle α3 in the second movement path in which the rotation radius decreases as the cam member 20 rotates.
The curvatures of the first moving path 31b and the second moving path 31c at the junction point 31d are substantially the same.

44 is a pin erected on the back surface of chassis 1, 45 is a load link pivotally supported by this pin 45, and 46 is this load link
A link connecting between 45 and the guide base 7, 47 is a gear plate pivotally supported by the pin 44, and a tension spring 48 is stretched between the gear plate 47 and the load link 45. 49 is a blanket fixed to chassis 1, 50 is a gear pivotally supported by this bracket 49,
50 is through the hole 51 formed in the chassis 1
On both sides of the chassis 1, and is engaged with the gear plate 47 on the back side of the chassis 1.

52 is a pin standing on the chassis 1, 53 is a guide arm pivotally supported by the pin 52, and the gear portion formed on the guide arm 53 is a portion protruding toward the chassis 1 surface side of the gear 50. Are engaged. Reference numeral 54 is a tape guide pivotally supported by the guide arm 53, and reference numeral 55 is a positioning pin that is in a positional relationship with which the guide arm 53 comes into contact when the guide arm 53 rotates clockwise in the drawing, and is erected on the chassis 1.

Reference numeral 56 is a pin provided upright on the back surface side of the chassis 1, 57 is a load link pivotally supported by the pin 56, and 58 is a link connecting the load link 57 and the guide base 8.
Reference numeral 59 is a pin provided upright on the surface side of the chassis 1, 60 is a tension arm pivotally supported by the pin 59, and 61 is a spring for biasing the tension arm 60 counterclockwise in the drawing. Reference numerals 62 and 63 are reel stands, and 64 is a tension band hung between the tension arm 60 and the chassis 1 so as to wind the reel stand 62. 65, 66 and 67 are tape guides provided upright on the surface side of the chassis 1.

Next, the operation will be described. 1 and 2 show an unloading state, in which the magnetic tape 4 is stored inside the tape cassette 3. The cam member 20 is at the most counterclockwise rotated position, and the lower pin portion 30b of the arm 29 is engaged with the circular center portion 31a of the cam groove 31. Further, although the load links 45 and 57 are not shown, the cam member 2
In the unloading state, the guide post members 7 and 8 are held at positions such that they are arranged inside the tape cassette 3, as shown in FIG. . Although the gear plate 47 is given a moment by a tension spring 48, it abuts at a predetermined position of the load link 45, and the relative positional relationship between the gear plate 47 and the load link 45 is maintained at a predetermined angle. There is.
Since the guide arm 53 is engaged with the gear plate 47 via the gear 50, the position of the guide arm 53 is also fixed. The pinch roller arm 15 is biased counterclockwise in the figure by a pinch roller returning member 19 composed of a tension spring, and its position is determined by contacting with the guide arm 53.

When the cam member 20 rotates clockwise in the drawing by the driving of the loading motor 22, the load link 45 rotates clockwise in the drawing and the load link 57 rotates counterclockwise in the drawing in response to the cam member 20. The guide post members 7 and 8 move in the loading direction along the grooves 5 and 6. Further, since the gear plate 47 rotates together with the load link 45, the guide arm 53 rotates clockwise through the gear 50. Further, since the pinch roller arm 15 is in contact with the guide arm 53 by the biasing force of the pinch roller returning member 19, the pinch roller arm 15 rotates in the clockwise direction in the figure in response to the guide arm 53.

When the cam member 20 continues to rotate further, the guide arm 53
Contacts the positioning pin 55. On the other hand, since the load link 45 continues to rotate, the tension spring 48 is extended, and the guide arm 53 is pressed against the positioning pin 55 by the torque generated by this operation. And the guide post members 7,8
Comes into contact with the guide stoppers 9 and 10 to be in the first loading state as shown in FIG. At this time, the pinch roller arm 15 is kept in contact with the guide arm 53, and the pinch roller 17 is not yet in contact with the capstan shaft 11. In addition, the lower pin member 30b erected on the arm 29
Engages with the outermost concentric circle portion 31a of the cam groove 31, and the arm 29 has not yet rotated. In such a first loading state, the magnetic tape 4 is run by driving the reels 62 and 63.

When the rotation of the cam member 20 continues, the lower pin portion 30b moves into the cam groove 3
The first moving path 31b of 1 is engaged, and the arm 29 rotates counterclockwise in the drawing. The moving range of the engaging member 31a at this time is referred to as a first moving range. At this time, the pin-shaped engaging member 30a is in a positional relationship of abutting the inclined portion 18a of the pinch roller urging member 18, and the rotation of the arm 29 causes the inclined portion 18a to receive a load in the C direction in the drawing. Here, the pinch roller urging member 18 is composed of a torsion spring and presses the contact portion 15a of the pinch roller arm 15 in the D direction in the drawing and the contact portion 15d in the C direction in the drawing. The torque due to is much larger than the moment around the pin 16 by the pinch roller returning member 19, so the foot angle of the pinch roller urging member 18 does not displace, and it rotates together with the pinch roller arm 15 in the direction c in the figure. Move. When the rotation of the arm 29 advances to a predetermined angle, the pinch roller
17 contacts the capstan shaft 11 and is brought into a state as shown in FIG.

When the cam member 20 further rotates, the lower pin portion 30b engages with the second movement path 31c of the cam groove 31. The movement range of the pin-shaped engaging member 30a at this time is referred to as a second movement range. Since the pinch roller 17 is in contact with the capstan shaft 11, the pinch roller arm 15 cannot rotate. Therefore, the arm 29
By the rotation, the pin-shaped engaging member 30a presses the inclined portion 18a of the pinch roller urging member 18 in the C direction in the figure. Then, as shown in FIG. 5, the pinch roller urging member
A gap 68 is generated between 18 and the contact portion 15a. Until now, the pinch roller arm 15 receives a moment from the pinch roller urging member 18 in the direction D in the figure received from the contact portion 15a and a moment in the direction C in the figure received from the contact member 15b. Although they are balanced with the same moment, the pinch roller arm 15 receives only the moment in the direction C in the figure from the contact portion 15b due to the gap 68. That is, the pinch roller 17 can be pressed against the capstan shaft 11 by this moment.

FIG. 8 shows the balance of forces when the inclined portion 18a of the pinch roller urging member 18 receives a load from the pin-shaped engaging member 30a when shifting from the state of FIG. 4 to the state of FIG. Inclined part 18
If a has an angle of θ with the driving direction of the pin-shaped engaging member 30a, the acting force given by the pin-shaped engaging member 30a is F
When set to 3, the pinch roller urging member 18 receives a force F1 perpendicular to the inclined portion 18a. The force of F1 is a force that actually gives a moment to the pinch roller arm 15, and the moment pushes the pinch roller 17 against the capstan shaft 11. Between F1 and F3, the relational expression of F1 ＝ F3 / sinθ holds. It is desirable for θ to be a small value of 45 ° or less. For example, if θ is set to 15 °, F1 = 3.86 x F3, and the moment of the pinch roller arm 15 is generated by F1 which is 3.86 times the force of F3. can do. pin
30 is engaged with the cam groove 31 of the cam member 20,
The driving force of the cam member 20 is small, so that the pinch roller 17 can be driven by the capstan shaft.
You will be able to press strongly to 11.

When the magnetic tape 4 reaches the second loading position as shown in FIG. 5 in this way, the magnetic tape 4 is pressed by the pinch roller 17 and the capstan shaft 11, and the tape can be run by the rotation drive of the capstan motor 13. I can.

In the embodiment described above according to the present invention, a twist spring is used as the pinch roller urging member 18, and the pin-shaped engaging member 30a is brought into direct contact with the twist spring 18. However, the concept of using a tension spring as shown in FIG. 9 can be easily considered. In FIG. 9, 16 is a pin standing on the chassis 1, and 15 is this pin 16
A pinch roller arm pivotally supported on the pin 16, a pivot plate pivotally supported on the pin 16 coaxially with the pinch roller arm 15, and a pin 70 on the hook portion 69a of the pivot plate 69 and the pinch roller arm 15. The tension coil spring 69b hung between the provided pins 71 is an inclined portion of the rotating plate 69, and 69c is a straight portion, and the rotating plate 69 and the tension coil spring 70 constitute the pinch roller urging member 18. Has been done. Reference numeral 15a is an abutting portion formed on a part of the pinch roller arm 15 and located at a position where it abuts on the rotating plate 69. Since the other components are the same as those of the embodiment according to the present invention shown in FIGS. 1 to 7, description thereof will be omitted. Next, the operation of the mechanism configured as shown in FIG. 9 will be described. Tension coil spring 70
Always urges the rotating plate 69 counterclockwise, and when the pin-shaped engaging member 30a does not contact the rotating plate 69, the rotating plate 69 is pressed by the contact portion 15a. . By driving the cam member 20, the arm 29 rotates counterclockwise,
It contacts the inclined part 69b of the rotating plate 69, and the arm 29
When is rotated, the rotating plate 69 is rotated clockwise in the drawing, and a gap 68 is formed between the rotating plate 69 and the contact portion 15a. Therefore, the pinch roller arm 15 receives the load from the rotating plate 69 only from the pin 71, and the moment due to this load causes the pinch roller 17 to be pressed against the capstan shaft 11. Then, by setting the angle θ formed by the inclined portion 69b of the rotating plate 69 and the linear portion 69c to a small value of 45 ° or less, a large pressing force of the pinch roller 17 is generated by a small driving torque of the cam member 20. You can As described above, even when the tension coil spring 70 is used, it is possible to obtain the same action as when the torsion spring is used.

Further, if the rotating plate 69 is used as shown in FIG. 9, the same effect can be obtained not only by using the tension coil spring 70 but also by using other compression springs or torsion springs. That is,
One on the rotating plate 69, the other on the pinch roller arm 15
The rotary plate 69 may be always biased counterclockwise in the figure.

In the embodiment shown in FIGS. 1 to 9, the pinch roller urging member 18 and the inclined portion 18a of the rotating plate 69,
Although the shape between 69b and the linear portions 18b and 69c is bent, the two may be connected by an arc, and the inclined portions 18a and 69c may be connected.
b may have a curved shape instead of a straight shape.

Further, in the embodiment shown in FIGS. 1 to 9, as shown in FIG. 6, the joining point 31d of the first moving path 31b and the second moving path 31c of the cam groove 31 is connected with the same curvature. However, as shown in FIG. 10, the curvature at the junction point 31d may be changed. That is, the first movement path 31b is located between the lower pin portion 30 and the lower pin portion 30 in FIGS. 3 to 4 in the embodiment according to the present invention.
It is a part where b is engaged and does not require a large driving force.
Therefore, the first movement path 31b can be designed so that the radius of gyration of the lower pin portion 30b changes greatly at a relatively small angle of α2 for the cam member 20. On the other hand, the second movement path 31c is a range where a strong pressing force is required for the pinch roller 17 at the portion where the lower pin portion is engaged between FIGS. 4 and 5, so that the cam member 20 has a large α3. The second movement path 31c can be designed so that the pin 30 can obtain a predetermined change in the radius of gyration when rotating the angle.

Further, in the embodiment shown in FIGS. 1 to 9,
The lower pin portion 30b and the pin-shaped engaging member 31a are pins that are erected coaxially on the arm 29, but they do not have to be coaxial. Further, the lower pin portion 30b and the pin-shaped engaging member 30a do not necessarily have to be erected on the same arm 29. First
FIG. 1 shows another embodiment in which the lower pin portion 30b and the pin-shaped engaging member 30a are not erected on the same part. In the figure, 29 is an arm pivotally supported by the pin 28, and 29a is this arm. Arm 2
Extension arms of 9 and 72 are pins that are erected on chassis 1, 2
Reference numeral 0 denotes a cam member pivotally supported by the pin 72, which is rotated by a drive source such as an electric motor. 73 is a pin erected on the chassis 1, 74 is an arm pivotally supported by the pin 73, and 75 is a pin 76, 77 between the extension arm 29a of the arm 29 and the arm 74. It is a linked link. 30b is a lower pin portion erected on the arm 74, which is a chassis 1
It penetrates through the elongated hole 1a and is engaged with the cam groove 31 formed in the cam member 20. The other components are the same as those in the embodiment shown in FIGS. 1 to 7, and their explanations are omitted.

With the configuration shown in FIG. 11 in this way, when the cam member 20 rotates, the lower pin portion 30b engages with the cam groove 31, so that the arm 74 rotates about the pin 73. Move. Then, the rotation of the arm 74 becomes the reciprocating motion of the link 75, and the arm 29 is rotated. Therefore, FIGS. 1 to 7
Similar to the operation description in the figure, in the first movement range of the pin-shaped engaging member 30a, the pinch roller arm 15 and the pinch roller urging member 18 move in the direction of contacting the capstan shaft while maintaining the integrated state. In the second movement range of the engaging member 30b, however, the pinch roller urging member 18 is pressed and deformed by the pin-shaped engaging member 30a, and the pinch roller 17 can be pressed against the capstan shaft 11.

〔The invention's effect〕

As described above, according to the present invention, the pinch roller urging member having the inclined portion at one end is stretched inside the pinch roller arm, and the pin-shaped engaging member that responds to the cam member is provided on the inclined portion. A state in which the pin-shaped engaging member abuts against the inclined portion of the pinch roller urging member in the first movement range of the pin-shaped engaging member so that the pinch roller urging member is not deformed. While holding, the pinch roller arm is rotated until the pinch roller comes into contact with the capstan shaft, and then in the second movement range of the pin-shaped engaging member,
The pin-shaped engaging member abuts the inclined portion of the pinch roller urging member at an angle of 45 ° or less and moves while deforming the pinch roller urging member, so that the pinch roller pressing force is applied to the capstan shaft. Therefore, it is possible to obtain the movement of the pinch roller arm and the pressure contact operation of the pinch roller to the capstan shaft with a stable and small driving force with a configuration having a small number of parts.

[Brief description of drawings]

FIG. 1 is a plan view showing a pinch roller pressure contact mechanism according to an embodiment of the present invention, and FIGS. 2 to 5 are main part plan views showing the operation of the pinch roller pressure contact mechanism shown in FIG. 1, respectively. The figure shows the cam member of the pinch roller pressure contact mechanism shown in FIG.
FIG. 7 is a plan view showing the details of the main part of FIG. 20, FIG. 7 is an inclined view showing the assembly of the peripheral portion of the pinch roller arm 15 of the pinch roller press contact mechanism shown in FIG. 1, and FIG. 8 is the pinch roller shown in FIG. FIG. 9 is a plan view of a main part showing the relationship of loads applied to the pinch roller urging member 18 of the press contact mechanism, FIG. 9 is a plan view of the main part shown in FIG. 6 showing another embodiment of the present invention, and FIG. FIG. 6 is a plan view of relevant parts of another embodiment of the present invention, and FIG. 11 is a plan view of relevant parts of FIG. 5 showing another embodiment of the present invention.
FIG. 14 is a plan view showing a conventional pinch roller pressing mechanism. In the figure, 1 ... chassis, 4 ... magnetic tape, 11 ...
… Capstan shaft, 15 …… Pinch roller arm, 17 ……
Pinch roller, 18 ... pinch roller biasing member, 20 ... cam member, 30a ... pin-shaped engaging member. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A pinch roller press-contact mechanism for pressing a pinch roller against a capstan shaft, wherein the pinch roller arm supports the pinch roller so as to be detachable from the capstan shaft, and a predetermined inclined portion at one end. A pinch roller urging member stretched around the pinch roller arm and a drive source such as an electric motor in a first direction to bring the pinch roller closer to the capstan shaft or the pinch roller to the capstan. A cam member that moves in either of the second directions to be separated from the shaft, abuts the inclined portion in response to the cam member that operates in the first direction, and operates in the second direction. An engaging member that moves away from the inclined portion in response to the cam member, and the inclined portion forms a moving direction of the engaging member that is in contact with the inclined portion. The inclined portion is configured so that the degree is 45 ° or less, and when the cam member operates in the first direction, the inclined portion receives the acting force in the moving direction of the engaging member from the engaging member. , A force perpendicular to the inclined portion is applied to the inclined portion to deform the pinch roller urging member, and the pinch roller is urged by the elastic restoring force of the deformed pinch roller urging member. A pinch roller pressure contact mechanism characterized in that it is in pressure contact with the.