JPH04160261A - Overload protection device - Google Patents

Abstract

PURPOSE:To absorb an overload securely in a simple structure by providing locking parts at the superposing parts of power point side branch arms and operation point side branch arms provided at the sides in the torque operating direction of a flexure arm of a torque delivery arm, and separating the locking parts by a torque input at a specific value or higher. CONSTITUTION:A torque delivery arm 10 makes its lower end where an input shaft 12 is provided in a power point side part 14, and its upper end where a locking pin 18 to engage to an output shaft 16 in an operating point side part 20. Between the power point side part 14 and the operating point side part 20, a flexure arm 24 is arranged on the center line L combining the center of the input shaft 12 and the center of the locking pin 18, and power point side branch arms 26 and 26a, and operating point side branch arms 28 and 28a are formed in circular arc forms placing the center O on the center line L respectively. The tips of these arms are superposed at both ends of the flexure arm 24, and demountable locking parts 32 and 32a are provided there. The engaging condition of fitting projections 36 and 36a, and fitting recesses 34 and 34a at the locking parts 32 and 32a is set beforehand to be separated when a specific excessive torque is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an overload protection device provided on a torque transmission arm.

(Prior Art) Generally, many arms are used for transmitting torque. For example, the torque transmitting arm may simply be a link of a link mechanism, a torque wrench, or the like.

In addition to this, there is a cam type pick-and-place device disclosed in Japanese Utility Model Application Publication No. 1-1830, which uses the torque transmission arm.

The cam-type pick-and-place device is a device that converts input shaft rotation into axial reciprocating motion and rotary motion and transmits the same to the output shaft.A cam mechanism is used to convert the reciprocating motion and rotary motion into a compound motion. is used.

That is, the cam mechanism is provided with a cam groove and a tapered rib that each form a predetermined geometric curve and are rotated by an input shaft, and conversion into reciprocating motion is performed via a swing arm guided by the cam groove. At the same time, the conversion to rotational motion is performed via a cam follower that is in sliding contact with the taber rib.

In other words, in the swinging arm that converts into reciprocating motion, the fulcrum provided at the base end is pivoted to the housing, the force point provided at the intermediate portion is fitted into the cam groove, and the free end portion is pivoted to the housing. A point of action provided is engaged with the output shaft.

The swing arm swings around the fulcrum as the cam groove rotates, and the output shaft reciprocates in accordance with the swing angle displacement at this time. The torque generated in the movable arm is also transmitted to the output shaft as a force for reciprocating the output shaft.

Therefore, the swing arm also has a function as a torque transmission arm.

(Problem to be solved by the invention) However, the conventional swinging arm is simply formed into a rigid body, and the swinging force of the swinging arm, which is the total torque, can be reliably transmitted to the output shaft. .

However, in the stroke in which the output shaft is reciprocated,
If the movement of the output shaft is obstructed by some kind of obstacle, an excessive load will be applied to the swing arm, which may cause a failure.

Therefore, in the past, an overload absorbing member such as a spring or a hydraulic or pneumatic piston was interposed in the power transmission path from the input shaft to the output shaft via the swing arm to absorb the overload. .

However, when an overload absorbing member is interposed in this way, the rigidity of the power transmission path decreases, causing vibration, and the device for absorbing this overload becomes complicated. There was a problem in that it forced an increase in costs.

In view of such conventional problems, the present invention has a simple configuration that can reliably absorb overload, and furthermore, maintains the rigidity of the power transmission path in a predetermined load state until overload occurs. The purpose is to provide an overload protection device that can maintain high performance.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a flexible arm having a leaf spring function by connecting the force point side portion and the action point side portion of the torque transmission arm, and the flexible arm of the flexible arm. A force side branch arm and an action point side branch arm projecting from the force side portion and the action point side portion, respectively, in the side direction of the torque action direction, and the tip portions of the force side branch arm and the action point side branch arm are bent as described above. A configuration in which the locking portions overlap with each other on the sides of the arms and are removable and are provided at the overlapping portions, and the locking portions are disengaged when a torque of a predetermined value or more is applied to the torque transmission arm. shall be.

(Function) With the above configuration, the overload protection device of the present invention has the following features:
In a normal torque transmission state, the locking portion between the force point side branch arm and the action point side branch arm is in an engaged state, and the rigidity of the torque transmission arm is set to be high.

On the other hand, when a torque of a predetermined value or more is applied to the torque transmission arm, the locking portion is disengaged and the force point side branch arm and the application point side branch arm are moved relative to each other.

Therefore, the force point side portion and the action point side portion of the torque transmission arm are substantially connected only by the bending arm, and overload is absorbed by the bending deformation of the bending arm portion.

Further, when the overload is removed, the flexible arm is returned to its original state by the action of the spring, and when the flexible arm is returned in this way, the locking portion is engaged again and the normal torque transmission state is resumed. can do.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

That is, FIGS. 1 to 3 show one embodiment of the present invention, FIG. 1 is a front view of a single torque transmission arm 10 equipped with an overload protection device, and FIG. FIG. 3 is an explanatory diagram showing the torque transmission arm 1o in an operating state.

The torque transmission arm 1o is applied to, for example, an oscillator handler, and as shown in Figure i1, the lower end portion in the figure is attached to the input shaft 12 and rotated together with the input shaft 12, and the lower end portion on which the input shaft 12 is provided. is the emphasis side portion 14.

Further, a locking pin 18 that is engaged with the output shaft 16 shown in FIG. 2 is fixedly installed at the upper end of the torque transmission arm 10 in the figure, and the upper end where this locking pin 18 is provided is the point of action. It has a side portion 20.

The force side portion 14 and the force point side portion 20 are located on a center line connecting the center of the input shaft 12 and the center of the locking pin 18.
A flexible arm 24 is arranged to connect the two.

The bending arm 24 is designed to exert a leaf spring action against deformation in the direction of torque application, that is, in the left-right direction of the paper in FIG. It is set sufficiently small compared to the torque value.

Further, the force side portion 14 and the point of action side portion 20
A force side branch arm 26.degree. 26a and a force point side branch arm 28.28a are provided protruding from both sides of the bending arm 24 in the direction of torque action, that is, in the left-right direction in the figure.

The force point side branch arm 26.26a and the action point side branch arm 2
8.28a are each formed in an arc shape with the center O being on the center line located on the bending arm 24.

The force point side branch arm 26.26a and the action point side branch arm 2
The distal ends of the arms 8.28a are overlapped with each other on both sides of the flexible arm 24, and a removable locking portion 32.32a is provided between each of these overlapped portions 30.30a.

The locking portions 32, 32a are connected to the force side branch arm 26.2.
6a, and the action point side branch arm 2 corresponds to the engaging recesses 34, 34a.
8.28a, and the engagement convex portions 36, 36a formed on the inside thereof.

The engaging protrusions 36, 36a are each formed in a hemispherical shape, and the engaging protrusions 36, 36a and the engaging recesses 34, 34
The engagement state with a is set in advance so that it is disengaged when a predetermined excessive torque is applied to the torque transmission arm 10.

The torque transmission arm 10 of this embodiment having the above configuration is as follows:
The locking pin 18 provided on the force side portion 20 is engaged with the circumferential groove 38 of the output shaft 16 which is arranged in a torsional relationship perpendicular to the input shaft 12 provided on the force side portion 14, and the input shaft The output shaft 16 is reciprocated in the axial direction by swinging the torque transmission arm 10 as the torque transmission arm 12 is repeatedly rotated in the forward and reverse directions.

By the way, when power is transmitted from the input shaft 12 to the output shaft 18, when the locking portions 32, 32a are in the normal engaged state, the force side branch arm 26.26a and the application point side branch arm 28 .28a is connected, the rigidity of the torque transmission arm 1° is set high, and the input shaft 1
Two rotations can be reliably transmitted as reciprocating movement of the output shaft 18.

On the other hand, as shown in FIG.
If the movement is blocked by, for example, excessive torque acting on the torque transmission arm 10, in this case, as shown in the figure, the engagement recess 34 of the locking portion 32.32a
, 34a, and the force side branch arm 26.26a and the force point side branch arm 28, 288
will be moved relative to each other.

In this way, after the locking portions 32, 32a are disengaged, no torque is transmitted through the branch arms 26, 26a and 28, 28a, and the force side portion 14 and the action point side portion 20 are separated. They are substantially connected only by the flexible arms 24.

At this time, since the bending arm 24 is set to be sufficiently small compared to the allowable torque value to be transmitted under normal conditions, the bending arm 24 is deflected and deformed by the excess torque.
This deformation of the flexible arm 24 allows excess torque to be absorbed.

Therefore, the power transmission path from the input shaft 12 to the output shaft 18 can be prevented from being damaged.

Note that since the flexible arm 24 exhibits a leaf spring function, when the cause of the excessive torque is removed, the flexible arm 2
4 is returned to its original upright state by the action of the spring, and when the flexible arm 24 is returned in this way, the engaging convex portions 36 and 36g of the locking portions 32 and 32a are relocked in the engaging concave portions 34 and 34a. automatically returns to the normal torque transmission state.

Further, the locking portions 32', 32a have engaging convex portions 36°36
By accurately controlling the shape of the convex portion a and the shape of the concave portions of the engaging recesses 34, 34a, it is possible to minimize variations in the position when returned.

By the way, in the embodiment described above, in constructing the locking portion 32° 32a, the engaging recesses 34, 34a are formed in the force side branch arms 26° 26a, and the engagement recesses 34, 34a are formed in the force side branch arms 26, 28.
Although the case in which the engagement convex portions 36, 36a are formed on the force side branch arms 26, 26al:: Engagement convex portion 2, the engagement concave portion is formed on the force side branch arm 28, 28a is disclosed. It may be formed.

Further, as shown in FIG. 4, a roller 40,
40a, and engagement recesses 42.42a and 44,44 for engaging the rollers 40, 40a with the force side branch arms 26, 26a and the action point side branch arm 28.28a.
By forming the respective locking portions 32 and 3
2a can also be configured.

Furthermore, as shown in FIG.
6a has a continuous notch on the distal end side and a locking portion 32,
By making the forming radii R1 and R2 of 32a different on the left and right sides, the allowable torque value for interrupting torque transmission can be changed between the forward and backward paths of the oscillated torque transmission arm 10.

In each of the embodiments described above, the force side branch arm 26.2
Although the case where the force side branch arms 6a and the force side branch arms 2g and 28a are provided on both sides of the flexible arm 24 is disclosed, the present invention is not limited to this. A similar function can be achieved even when a branch arm on the point of action side is provided.

In addition to the oscillator handler used in the above embodiments, the torque transmission arm equipped with the overload protection device of the present invention can also be used as a positive drive device such as a roller cam or parallel cam, or as a tool. It can also be applied to commonly used torque wrenches and the like.

(Effects of the Invention) As explained above, in the overload protection device of the present invention, the force point side portion and the application point side portion of the torque transmission arm are connected via the bending arm, and the torque action of the bending arm is A locking part is provided at the overlapping part of the force point side branch arm and the action point side branch arm provided on the side of the direction, and this locking part is disengaged by a torque input of more than a predetermined value, so that it will not lock in the event of an overload. It is possible to prevent damage to the power transmission path by absorbing excessive torque due to the deformation of the bending arm due to the stop portion coming off.

Furthermore, since the flexible arm has a leaf spring function, the torque transmission arm can automatically return to the normal torque transmission state when the overload is removed, which provides various excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a front view showing one embodiment of a torque transmission arm equipped with an overload protection device according to the present invention, FIG. 2 is a configuration diagram showing an example of use of a torque transmission arm to which the present invention is applied, and FIG. FIG. 4 is a front view showing another embodiment of the invention, and FIG. 5 is a front view showing still another embodiment of the invention. 10... Torque transmission arm 12... Input shaft 14... Force side part 16... Output shaft 20... Point of action side part 24... Flexible arm 26. 26a... Force side branch arm 28.28a...Application point side branch arm 30.30a...Overlapping part 32.32B...Locking part Patent Applicant Sankyo Seisakusho Co., Ltd. Representative
Person Patent attorney - Kensuke Iro Patent attorney Masatoshi Matsumoto Figure 1 tl Figure 4

Claims (1)

[Claims] A flexible arm that connects the force side part and the application point side part of the torque transmission arm and has a leaf spring function; The force point side branch arm and the action point side branch arm, and the distal ends of the force point side branch arm and the action point side branch arm are overlapped with each other on the side of the bending arm, and a removable engagement is provided at this overlapping portion. What is claimed is: 1. An overload protection device comprising: a locking portion; the locking portion is released when a torque of a predetermined value or more is applied to a torque transmission arm.