JPH04244627A - Variable torque type toque limiter - Google Patents

Abstract

PURPOSE:To make the magnitude of torque acting on a rotating member variable during its rotation by moving a guided ring through a guide ring unitedly formed with the rotating member, and disengaging an engaging projection from a control pawl during the moving stroke of the guided ring. CONSTITUTION:In the case where a variable torque type torque limiter is applied to the opening-closing mechanism for the cover 29 of a word processor or the like, when the cover 29 is closed from its opened state where a control pawl 18 engages with an engaging projection 25, a rotating member 7 rotates positively to unitedly rotate a guide ring 20. A guided ring 19 fitted in the thread groove of the guide ring therefore moves toward a spring seat 1. A spring sleeve 8 unitedly formed with the rotating member 7 also rotates, but since a control ring 16 engages with the guided ring 19, the dragging of a coil spring 12 does not occur. Thus sliding resistance between the coil spring 12 and the spring sleeve 8 is comparatively weak, and the cover 29 has been softly closed. When the control pawl 18 thereafter disengages the engaging projection 25, the coil spring 12 diminishes in its diameter to make high torque act on the rotating member 7.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable torque type torque limiter that can automatically change the set torque between high and low levels.

0002

[Prior Art] In various types of equipment (e.g. copy machines, word processors, personal computers, etc.) in which a lid is attached to a housing via a hinge, in order to prevent the lid from closing forcefully when the lid is closed, it is necessary to A means, a so-called damper, is provided for applying a large torque to the motor.

0003

A conventional damper using an air cylinder or the like has problems in that it takes up installation space and is expensive. Furthermore, since a constant torque is applied over almost the entire closing stroke to provide damping, a large load is applied to the damper over the entire length of the stroke. Therefore, there is a problem that affects the life of the damper.

[0004] Therefore, the technical object of the present invention is to reduce the load acting on the torque generating section by automatically changing the magnitude of torque between the first half and the second half of the stroke.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a support shaft protruding from the center of the spring seat, a rotating member attached to the tip of the support shaft, and a rotating member that rotates with the spring seat. A spring sleeve with an axial slit is fitted around the support shaft between the spring seat and the sleeve, and one end of the spring sleeve is engaged with the rotating member to prevent relative rotation, and the spring seat rotates between the spring seat and the sleeve. In a torque limiter in which one end of a coil spring wound in a direction opposite to the normal rotation direction of the member is engaged with a spring seat, and the other end is wound around a spring sleeve in an enlarged diameter state, To,
A control ring, a guided ring, and a guide ring integrated with a rotating member are fitted in order from the inside, one end of a coil spring is engaged with the control ring, and a control claw is provided in a required range in the axial direction on the outer peripheral surface of the control ring, An engaging protrusion is provided on the inner circumferential surface of the guided ring, which engages with the control pawl in the rotational direction and is relatively movable in the axial direction, and the guided ring is rotated on the inner circumferential surface of the guide ring. The members are screwed together so that they can move forward and backward through thread grooves in the same direction as the normal rotational direction of the members, and one end of the guided ring is fitted into the guide groove of the spring seat.

[0006]

[Operation] When the rotating member is rotated in the forward direction, the guided ring, which is threaded into the guide ring integral with the rotating member, moves toward the spring seat. Also, the spring sleeve engaged with the rotating member rotates at the same time, but the coil spring around it is engaged with the control ring, which in turn is engaged with the guided ring, so the coil spring does not wrap around it. do not have. Therefore, the sliding resistance between the coil spring and the spring sleeve is relatively small, and therefore the torque acting on the rotating member is also small.

[0007] When the rotation angle of the rotating member further increases, the engaging protrusion of the guided ring disengages from the control claw of the control ring, and the coil spring is dragged in the direction of increasing the amount of winding due to the rotation of the spring sleeve, causing its diameter to contract. , the spring sleeve is also reduced in diameter at the same time. Therefore, the sliding resistance between the coil spring and the spring sleeve increases, and the torque acting on the rotating member increases.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A variable torque type torque limiter according to an embodiment shown in the accompanying drawings has a spring seat 1. This spring seat 1 consists of a small diameter part 2 and a large diameter part 3, and the large diameter part 3 has two centrally symmetrical parts.
Wide guide grooves 4 (see FIG. 5) are provided in the axial direction at certain locations. One end of the support shaft 5 is inserted into the center hole of the spring seat 1 and fixed by a pin 6 passing through the large diameter portion 3 in the radial direction. The tip of the support shaft 5 protrudes from the small diameter portion 2 of the spring seat 1. A rotating member 7 such as a gear is attached to the tip of the protruding portion, and a spring sleeve 8 is installed between the rotating member 7 and the spring seat 1. is intervened. The spring sleeve 8 has an axial slit 9, and when an inward force is applied in the radial direction, the slit 9 narrows and contracts in diameter, and when the force is removed, it returns to its original diameter due to elasticity. An engagement recess 10 is provided at the outer end of the spring sleeve 8, and is loosely engaged with an engagement protrusion 11 formed on the inner surface of the rotating member 7. For this reason, the rotating member 7
The spring sleeve 8 is prevented from relative rotation, but allows the spring sleeve 8 to expand and contract in the radial direction.

A coil spring 12 is wound around the outer peripheral surfaces of the spring seat 1 and the spring sleeve 8. The coil spring 12 is a wire with a rectangular cross section wound tightly in a coil shape, and an engagement end 13 extending in the axial direction is formed at the end on the spring seat 1 side, and a radial end 13 is formed at the other end. An engaging end 14 is formed which is bent in the direction. coil spring 1
The inner diameter of the spring sleeve 8 in its natural state is equal to or smaller than the outer diameter of the small diameter portion 2 of the spring seat 1, and is also smaller than the outer diameter of the spring sleeve 8 in its natural state. Therefore, the engaging end 14 of the coil spring 12 on the spring seat 1 side is connected to the slit 15 formed in the large diameter portion 3 of the spring seat 1 (see FIG. 5).
is engaged with. In addition, the coil spring 12 is connected to the spring sleeve 8.
can be wrapped around it with the diameter reduced slightly. The winding direction of the coil spring 12 when viewed from the rotating member 7 side is opposite to the normal rotation direction of the rotating member 7 (see arrow a in FIGS. 1 and 5), that is, it is formed in a right-handed winding direction.

A control ring 16 is loosely fitted around the coil spring 12 between the large diameter portion 3 of the spring seat 1 and the rotating member 7. An engagement recess 17 is formed in the inner end surface of the control ring 16 on the rotating member 7 side, and the engagement end 13 of the coil spring 12 is engaged with the engagement recess 17. Further, a control pawl 18 is provided on the outer peripheral surface of the control ring 16 in the first half thereof (see FIG. 5). A guided ring 19 is fitted on the outside of the control ring 16, and a guide ring 20 is fitted on the outside thereof.

The guide ring 20 is integrated with the boss portion of the rotating member 7 by a pin 21. Further, a thread groove 22 with a coarse pitch is formed on the inner circumferential surface of the guide ring 20. This thread groove 22 is formed in the same direction as the forward rotation direction of the rotating member 7,
That is, it is formed to be left-handed.

A male thread 23 that fits into the thread groove 22 is formed on the outer peripheral surface of the guided ring 19 . A guide piece 24 that fits into the guide groove 4 of the spring seat 1 is formed at the rear end of the guided ring 19 . Also, the guided ring 19
An engaging protrusion 25 is formed on the inner circumferential surface of (see FIG. 2),
The guided ring 19 engages with the control pawl 18 of the control ring 16 in the state shown in FIG. 1 in which it advances toward the rotating member 7 side.

A housing 26 is fitted around the guide ring 20 and the spring seat 1, and the stepped portion 27 on the inner circumferential surface of the housing 26 contacts the large diameter portion 3 of the spring seat 1, and the inner circumferential surface of the tip portion is brought into contact with the outer peripheral surface of one end of the guide ring 20 to position the guide ring 20.

The torque limiter of the embodiment is constructed as described above, and is attached by fixing the housing 26 to the case body 28. Further, the gear 30 attached to the lid 29 (see FIG. 6) is engaged with the rotating member 7.

As shown in FIG. 6, when the lid 29 is open, the control claw 18 is engaged with the engagement protrusion 25 (see FIG.
reference). When the lid 29 starts to close from this state, the rotating member 7 rotates forward, and the guide ring 20 integrated with it rotates, so the guided ring 19 fitted in the thread groove 22 rotates.
moves to the spring seat 1 side. The spring sleeve 8 integral with the rotating member 7 also rotates, but the coil spring 12 is engaged with the control ring 16, and the control ring 16 is further engaged with the guided ring 19, so that the coil spring 12 is dragged. does not occur. Therefore, the sliding resistance between the coil spring 12 and the spring sleeve 8 is relatively small, and therefore the torque acting on the rotating member 7 is relatively low, and the lid 2
9 is lightly closed.

When the lid 29 is further closed as shown in FIG. 7, the rotation angle of the rotating member 7 increases, so that the guided ring 1
9 moves further toward the spring seat 1 side. As a result, the control pawl 18 is disengaged from the engagement protrusion 25, as shown in FIGS. 3 and 4. For this reason, the end of the coil spring 12 is dragged by the spring sleeve 8, and the diameter of the coil spring 12 is reduced, and the spring sleeve 8
As a result, a large sliding resistance is generated between the coil spring 12 and the spring sleeve 8. Therefore, high torque acts on the rotating member 7, making it difficult to close the lid 29.

Furthermore, when the lid 29 is opened from the completely closed state as shown in FIG. 8 as shown in FIG. 9, the rotary member 7 rotates in the opposite direction, so that the The guide ring 19 returns to its original state, and the control pawl 18 engages with the engagement protrusion 25 again.

However, since a force opposite to the dragging direction acts on the coil spring 12, the sliding resistance is small. Therefore, the lid 29 is lightly opened.

[0019]

As described above, the present invention moves the guided ring by means of a guide ring that is integrated with the rotating member, and in the middle of the movement stroke, the engaging protrusion provided on the guided ring is moved away from the control pawl of the control ring. I made it come off, so
The magnitude of the torque acting on the rotating member can be changed from low torque to high torque during rotation of the rotating member. Therefore, when used in a lid opening/closing device, the range in which high torque acts can be set to the necessary minimum, and the life of the opening/closing device can be extended.

[Brief explanation of the drawing]

[Figure 1] Cross-sectional view when low torque is applied

[Figure 2] Cross-sectional view taken along line II-II in Figure 1

[Figure 3] Cross-sectional view when high torque is applied

[Figure 4] Cross-sectional view taken along the IV-IV line in Figure 3

[Figure 5] Exploded perspective view

[Figure 6] Explanatory diagram of action

[Figure 7] Explanatory diagram of action

[Figure 8] Explanatory diagram of action

[Figure 9] Explanatory diagram of action

[Explanation of symbols]

1 Spring seat 2 Small diameter part 3 Large diameter part 4 Guide groove 5 Support shaft 6 pin 7 Rotating member 8 Spring sleeve 9 Slit 10 Engagement recess 11 Engagement protrusion 12 Coil spring 13, 14 Engagement end 15 Slit 16 Control ring 17 Engagement recess 18 Control claw 19 Guided ring 20 Guide ring 21 pin 22 Thread groove 23 Male thread 24 Guide piece 25 Engagement protrusion 26 Housing 27 Stepped section 28 Case body 29 Lid 30 Gear

Claims (1)

[Claims] Claim 1: A support shaft is provided protruding from the center of the spring seat, a rotating member is attached to the tip of the support shaft, and an axial slit is provided around the support shaft between the spring seat and the rotating member. A spring sleeve is fitted, one end of the spring sleeve is engaged with a rotating member to prevent relative rotation, and one end of a coil spring is wound in a direction opposite to the normal rotational direction of the rotating member across the spring seat and the sleeve. In a torque limiter that engages a spring seat and has its other end wrapped around a spring sleeve in an enlarged diameter state, around the coil spring,
A control ring, a guided ring, and a guide ring integrated with a rotating member are fitted in order from the inside, one end of a coil spring is engaged with the control ring, and a control claw is provided in a required range in the axial direction on the outer peripheral surface of the control ring, An engaging protrusion is provided on the inner circumferential surface of the guided ring, which engages with the control pawl in the rotational direction and is relatively movable in the axial direction, and the guided ring is rotated on the inner circumferential surface of the guide ring. A variable torque torque limiter, characterized in that the member is screwed together so that it can move forward and backward through a screw groove in the same direction as the forward rotational direction of the member, and that one end of a guided ring is fitted into a guide groove of a spring seat.