JPH06147281A - Belt device - Google Patents

Abstract

PURPOSE:To provide a belt running device which can accurately carry a transmission belt to a proper position on the periphery of a pulley despite of arrangement of the pulleys, and to automatically put even the transmission belt with a short peripheral length on the pulleys. CONSTITUTION:A belt running device comprises a) a pair of rods 31 each having a groove, in which a belt B is fitted, formed in the inner side along a longitudinal direction; b) an opening closing mechanism 32 operated to unfold rods 31 between a position, where the rods are situated in a state to approach each other and in the vicinity of a common tangential line between pulleys 2U and 2D, brought into an approaching state, and parallel to each other, and a position where the rods have a longer distance therebetween than the above; c) a holding tool 33 on which the rods 31 and the opening and closing mechanism 32 are mounted; and d) a moving mechanism 34 to move the holding tool 33 from a position where the belt B is received to the outside position of the pulleys 2U and 2D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for automatically suspending a transmission belt between a plurality of pulleys during the manufacturing process thereof.

[0002]

2. Description of the Related Art Power transmission belts are used, for example, in the manufacturing process.
It is necessary to hang it between the pulleys at least once. A loop winding process can be performed by applying a predetermined tension by hanging an annular belt between a set of pulleys (usually two, but there may be three or more). And measure length, elongation and strength. Even when using the manufactured belt, depending on the application, it may be necessary to repeatedly hang the belt between the same pulleys.

In such a case, the pair of pulleys on which the power transmission belt is hung is usually such that the positional relationship between them is variable, that is, the axial distance can be changed. When hanging or removing the belt, the distance between the shafts is shortened (pulleys are brought closer to each other) to facilitate the work, and when the tension is applied for manufacturing, measurement and use, the distance between the shafts is increased.

On the other hand, as for the side on which the transmission belt is hung between the pulleys in a close state where the distance between the shafts is shortened, that is, as a so-called belt hanging device, those having the following functions are conventionally known. That is, by grasping the uppermost part of the belt, the belt is carried from the receiving position (the position where the belt is supplied) to the position of the pulley (the position where the belt surrounds a set of pulleys to be hung). . When the belt is positioned around the pulley, the belt is properly stretched and tension is given by opening the distance between the pulleys as described above.

[0005]

The conventional belting device as described above has the following disadvantages. In other words, (a) it is difficult to accurately convey the belt to the most desirable position outside the pulley because the transmission belt is moved to the position of the pulley by grasping only the uppermost portion. This is because swaying of the belt cannot be sufficiently prevented by grasping only a part of the annular belt. Further, since the belt is not entirely restrained but only a part of the belt is grasped, it is impossible to turn the belt sideways. Therefore, if the pulleys are lined up horizontally (horizontally) even if they are close to each other, or if the arrangement surface of the pulleys is horizontal (the axis of each pulley is vertical), belting is performed using such a conventional device. Is impossible.

(B) Since the transmission belt is carried to the pulley position without being deformed (that is, in a circular shape except that the shape is slightly changed by the action of gravity), the belt having a short circumference can be hung between a plurality of pulleys. Is difficult. If the diameter (inner diameter) of a circular belt is less than the outer dimension (or the diameter of the circumscribing circle) between the pulleys that are in close proximity to each other, for example, an operator can help to put the belt into an oval shape. If it is not deformed, the belt cannot be hung between the pulleys.

An object of the present invention is to enable the transmission belt to be accurately conveyed to an optimum position around the pulley regardless of the arrangement of the pulley, and even a transmission belt having a shorter circumference than the diameter of the pulley can be automatically hung on the pulley. The purpose of the present invention is to provide a belting device that can do this.

[0008]

SUMMARY OF THE INVENTION The belting device of the present invention comprises: a) a pair of rods having a groove into which a belt can be fitted, the rods being inwardly along the longitudinal direction; and b) close to a common tangent line of pulleys in an approaching state. And, the pair of rods are opened and closed between the positions which are substantially parallel to each other (each rod is substantially parallel to the common tangent line) (closed state) and the position having a space larger than that (open state). The opening / closing mechanism, c) the holder to which the rods and the opening / closing mechanism are attached, and d) the moving mechanism for moving the holder from the belt receiving position to the position outside the pulley are incorporated.

As described in claim 2, the moving mechanism of this apparatus has d-1) a swing arm which is turnable with respect to a fixed member, and d-2) has a tip at a right angle with a turning surface of the arm. The above holder is rotatably attached via a simple support shaft,
d-3) Fixed member so that the holder rotates in the opposite direction at the same angle as the swing angle of the arm (in other words, the relative rotation amount of the holder with respect to the arm matches the relative rotation amount of the fixing member with respect to the arm). It is more preferable to configure by connecting the and the holder.

[0010]

In the belt hooking device of the present invention, the transmission belt is hooked between predetermined pulleys by handling as follows.

First, the pair of rods described in a) are opened by the opening / closing mechanism in b), and are first placed at the belt receiving position together with the holder in c).

When the belts come inside the rods, the pair of rods are closed by the opening / closing mechanism (the above-mentioned closed state), and the belts are fitted into the grooves inside each rod. As a result, the positional relationship between the pair of rods is such that each rod is just outside the common tangent line of the pulleys in the approaching state and is substantially parallel to each tangent line (actually, at this point, The position is far from the pulley, but if you move it as follows, it will be in such a relationship), so the belt is from the original circle to the long line including the common tangential part along the inside of these rods. It can be transformed into a circular or musubi shape.

The holder is moved by the moving mechanism of d), and the power transmission belt is carried to the outside of the plurality of pulleys brought into the close state. The belt is sandwiched between the pair of rods, and moreover, most of the entire circumference (that is, the common tangential portion described above) is held in the groove inside the rod, so that the movement of this belt is prevented. It does not sway or fall off in the middle and is reliably carried with the rod to the proper position outside the pulley. In addition, because it has a shape that includes a common tangential part of the multiple pulleys to be hung (as described above, it is oval or musubi-like along the arrangement of the pulleys), so it cannot be hung on the outside of the pulleys. However, it can be positioned without any problems by this movement.

While the position between the pulleys is changed (the distance between the shafts is changed), the holder, the rod, and the like are kept as they are at the above-mentioned destination, and after the shafts are opened and some tension is applied to the belt. Then, the rod is opened and separated from the belt by the opening / closing mechanism, and returned to the original position together with the holder by the moving mechanism.

In the belt hooking device according to the second aspect of the invention, due to the structure of the moving mechanism, the holder itself including the rod and the opening / closing mechanism does not change its orientation (so-called parallel movement).
Move by turning movement. This is because when a swing arm in d-1) is swung by a predetermined angle, the holder rotatably attached to the tip of the arm as shown in d-2) is the same as the swing of the arm by the connection shown in d-3). This is because it rotates in the opposite direction by the angle. The holder will revolve with the arm about the rotation center (fixing member) of the arm at an angle (θ), so that the tip of that arm will rotate by (−θ) with respect to the arm. If so, the angle of the retainer does not change.

A moving mechanism for turning a swing arm or the like is simpler than a moving mechanism of a linear motion type using a ball screw, a rack and pinion, etc. It is usually necessary to lay out the related equipment in a radial fashion as it is turned to. However, when the holder (functional object) moves without changing the direction like this device, it is possible to arrange each related equipment including the pulley in parallel. That is,
For example, since the direction of the belt and the direction of the pulley at the receiving position described above are parallel to each other, a conveyor or the like that supplies the belt to the receiving position is parallel to the axial direction of the pulley of the inspection device. Can be placed in This means that related equipment can be efficiently and compactly laid out in a certain space.

[0017]

Embodiments of the present invention will be introduced below with reference to the drawings. The examples shown in FIGS. 1 to 4 are in the cover winding machine 1 for winding the cover cloth A on the surface of the rubber belt B in the manufacturing process of the transmission wrapped V belt and the like. In this example, a large number of unvulcanized rubber belts B to be wrapped around the cover are wound between the pulleys 2U and 2D of the cover winding machine 1 by the belt hooking device 30, and the lower pulley 2
Lower the position of D to give the belt B proper tension.

As shown in FIG. 1, the cover winding machine 1 includes pulleys 2U and 2D connected to a driving means (not shown), a belt hooking device 30 and the like, and a belt B on the pulleys 2U and 2D and a cover cloth A. Roll up roll 3 / 3a to cover
Detecting device 1 for detecting a seam (described later) on the cover cloth A
0, a tensioning device 5 that spreads the cloth A with a pin to detect it, a belt B supply conveyor 40 (see FIG. 3), and the like are attached. Hereinafter, first, the cover winding machine 1 will be generally described with reference to FIG.

The cover winder 1 wraps the surface of the belt B with the belt-shaped cover cloth A over the circumference of the belt B, and the edges of the cloth A are overlapped by several millimeters to ten and several millimeters and spliced together. . By the way, in order to supply the cover cloth A to the cover winding machine 1 as described above, there are some seams (joints where the cloths are overlapped at the time of manufacturing the cloth A, hereinafter referred to as material seams) existing in the cloth A itself. You have to pay attention to the position. The cloth A is a so-called bias cloth in which the fibers run obliquely though it is a long strip-shaped cloth,
It is difficult to eliminate such a material seam during manufacturing, but if this seam overlaps or becomes too close to the seam between the ends of the circumference wound around the belt B (hereinafter, referred to as the winding seam), both seams will be removed. This is because the bendability and the like are significantly different from the other portions in the vicinity of the point where is close to, which is not preferable in terms of the quality of the belt B.

Therefore, in the portion of the cover winding machine 1 where the cover cloth A is supplied, the position where the next cutting (cutting) is planned (the planned cutting position. End of winding on one belt B and winding on the next belt B) The detection device 10 detects whether or not there is a material seam in a specified dimensional range immediately before and after (a winding seam when being wound on the belt B at a boundary between the start and the beginning). Then, at the time of the detection, the stretching device 5 stretches the cloth A within the range without wrinkles. If it is found that there is a material seam within the size range, the cover winding machine 1 cuts a part of the cloth A with a cutting blade so that the position of the seam is far from the planned cutting position. .

The material seam detecting device 10 is mainly composed of a main body portion and a position adjusting portion. As shown in FIG. 1, the main body portion has a vertical flat surface 11 on which a cover cloth A is placed, The presence or absence of a seam is detected by detecting the displacement in the horizontal direction while rolling the roller 12. For the purpose of amplifying and detecting the displacement of the roller 12 to improve the accuracy, the roller 12 is placed in the middle of the swing arm 13 that swings around the pin 14.
Is attached to the arm 17 to detect the displacement.
It is installed near the swing end of 3. Reference numeral 20 in the figure is an air cylinder for moving the swing arm 13, the pin 14, etc. to the left and right in the figure to press the roller 12 onto the cloth A, reference numeral 2
Reference numeral 5 denotes an air cylinder that vertically moves the above portion in order to roll the roller 12 on the cloth A.

On the other hand, the position adjusting portion of the detection device 10 is the position (height) of the flat surface 11 that defines the range of the detection target.
Is adjusted to match the next cut position on the cover cloth A. As shown in the figure, the vertical guide rods 27 (there are two on the front side and the other side) and the long lengths hung in parallel with them. The synchro belt 28 and its driving means (not shown). The base 24 assembled with the above-mentioned main body portion is engaged with the guide rod 27 in the guide portion 24a so as to be movable up and down, and the engaging portion 24
It is fastened to a part of the belt 28 at b. By driving the belt 28 by an amount corresponding to the measured length of the belt B, the base 24 is moved up and down along with the main body portion of the apparatus 10 along the guide rod 27 to an appropriate height. The length of the belt B is such that when the pulley 2D is moved to give a predetermined tension to the belt B as will be described later, the pulley 2U
-The cover winder 1 automatically measures from the distance between 2D.

As the spreading device 5 for stretching the cover cloth A on the flat surface 11 for the above detection, as shown in FIG. 1, the cloth A is prevented from returning to the position immediately in front of the cutting blade 4 (upstream side). While arranging the leaf springs 6, the blades 7a are attached to a part of the rotatable roll 7 on the base 24 around which the cloth A is wound, and the roll 7 is directed in the reverse returning direction of the cloth A toward the blade 7a. A compressed air blowing nozzle 8 is provided so as to rotate. If the compressed air is blown from the nozzle 8 until the cloth A is pulled out as the belt B is rotated by the pulleys 2U and 2D and immediately after the stop, the backward-prevention force of the leaf spring 6 and the frictional force from the roll 7 are generated. , Cloth A
Is stretched without slack or wrinkles.

In order to wind the cover cloth A around the belt B in the cover winder 1, first, the pair of pulleys 2U.
Shorten the spaces between D and hang them on the belt B. Next, the pulleys 2U and 2D are widened to give a predetermined tension to the belt B, the tip of the cover cloth A is attached from the outside, and the pulleys 2U and 2D (one side) are driven to drive the belt B.
Circulate. As the belt B circulates, the cover cloth A
Although the cover cloth A is also pulled out, the cover cloth A is wound around the entire surface of the belt B while being pressed by the winding rolls 3 and 3a.

The lower pulley 2D of the pulleys 2U and 2D can be moved up and down like a virtual line in the figure. When the pulley 2D is above and close to the pulley 2U, it is easy to hang the belt B between the pulleys 2U and 2D, and when the position of the pulley 2D is lowered, tension can be applied to the hung belt B. . As a moving mechanism (not shown) of the pulley 2D, for example, the bearing box of the pulley 2D is engaged with a vertically oriented feed screw which is rotationally driven by a motor with a rotation speed detecting means. By means of a belt hanging device 30 which will be described later, one belt B is positioned outside the pulleys 2U and 2D so as to be located on the upper pulley 2
If it is the same as U, the lower pulley 2D moves down and the belt B
It is possible to know the circumferential length of the belt B from the position thereof (pulley interval, which can be known from the number of rotations of the motor, for example), while applying tension to the belt.

Belt B is attached to the pair of pulleys 2U and 2D.
The belt winding device 30 and the belt supply conveyor 40 are attached to the cover winding machine 1 as a device on the side where the belt is wound. The one belt B conveyed to the predetermined receiving position by the conveyor 40 is grasped by the belt hanging device 30 and conveyed to the outer peripheral positions of the pulleys 2U and 2D.

The belt supply conveyor 40 is constructed as shown in FIGS. That is, the roller 4 at one end
A conveyor belt 41 is stretched between the second roller and the other roller (not shown), and a swing-rotating hanger 43 is provided at the tip position thereof. When the conveyor belt 41 is circulated with the hanger 43 in the right solid line position in the figure, the belt B hung on the conveyor belt 41 is fed from the right until it hits the protrusion 43a of the hanger 43. When it is detected that the belt B has reached the position, the conveyor 40 stops the circulation of the conveyor belt 41 and moves the hanger 43 to the left side of the drawing by the air cylinder 43b to move the leading belt 41 to the imaginary line position, that is, It moves to the receiving position by the belting device 30.

The belt hooking device 30 handles the belt B at its receiving position in FIG. 3, and its structure is as follows. That is, first, as shown in FIG. 2, a clamp bar 31 which is a pair of bars with which the belt B can be sandwiched.
Is attached to the holder 33 swingably via the pin 31a. Each bar 31 has a base 31b directly connected to the pin 31a.
A long portion 31c is connected to the tip of the groove 31d, and a groove portion 31d (see FIG. 4) into which the belt B can be fitted is formed on the inside (sides facing each other). The size of the bar 31 is slightly longer so that the large and small belts B having different sizes can be grasped. Further, an opening / closing mechanism 32 is provided between the bases of both bars 31 and the holder 33 so that the bars 31 can be opened / closed around the pin 31a. This mechanism 32 includes an air cylinder 32a connected to both bars 31, and a synchronization link 32b and a guide pin 32c for symmetrically opening and closing both bars 31.
And a pin guide plate 32d and the like. Then, in order to move the above parts from the receiving position to the positions of the pulleys 2U and 2D, as shown in FIGS. 3 and 4, the moving mechanism 34 including the swing arm 36 is assembled with the holder 33.

According to the opening / closing mechanism 32, the clamp bar 31 is opened / closed as shown in FIG. That is, when the air cylinder 32a is extended, the bar 31 opens as shown by the phantom line in the figure, and the belt B in the natural state, that is, the supply conveyor 4 is shown.
Although it can be located outside the belt B in a state of being hung on the hanger 0 of 0 (see FIG. 3), when the cylinder 32a is contracted, it is closed as shown by the solid line in the drawing, and the belt B is deformed into an oval shape while the groove portion 31d is deformed. Hold inside. When the bars 31 are closed, the pulleys 2U and 2D are in a close state.
Since they are located substantially parallel to the outside near each common tangent (also shown in phantom in FIG. 2), the bar 31
The belt B held by is in an oval shape along the outside of the pulleys 2U and 2D.

The structure of the moving mechanism 34 will be described below in detail with reference to FIGS. First, the frame 35, which is a fixed member, is provided with the fixed support column 35a vertically upward. The bearing 36 is attached to the column 35a.
Attach the swing arm 36 rotatably via a,
Expansion and contraction of the air cylinder 36b allows it to swivel in a horizontal plane. A support shaft 37 is provided vertically downward at the tip of the arm 36, and the bearing 3 is centered on the support shaft 37.
The holder 33 is attached so as to be horizontally rotatable via 7a. As a result, the holder 33, the clamp bar 31 attached to the holder 33, and the like are swung, that is, revolved by the arm 36, and rotate at the tip thereof.

Regarding the moving mechanism 34, the toothed pulley 38a is fixed to the fixed support column 35a on the frame 35, while the pulley 38 having the same number of teeth is integrally formed with the holder 33.
b is attached, and both are synchronized (with teeth) belt 38c
Connected with. Since the pulleys 38a and 38b have the same number of teeth, the arm 36 pivots to rotate the pulley 38 on the side of the support column 35a.
When a relative rotation occurs with respect to a, the pulley 38b on the holder 33 side with respect to the arm 36 is rotated by an amount (angle) equal to the relative rotation amount of the pulley 38a with respect to the arm 36. This means that the support 35
The rotation angle of the arm 36 centering on a (that is, the holder 3
Revolution angle of 3. The angle θ ₁ in FIG. 4 and the rotation angle of the holder 33 on the arm 36 (the rotation angle; θ _{2 in} FIG. 4) are in the opposite directions and have the same size (θ ₁ = −θ ₂ ). As a result, the holder 33 changes its position without changing its orientation as shown in FIG. Therefore, therefore, the orientation of the supply conveyor 40 can be made parallel to the axis of the pulleys 2U and 2D of the cover winding machine 1.

The belt B is attached by the belt hanging device 30 or the like.
The procedure for hanging the pulley on the pulleys 2U and 2D is as follows.

The pair of clamp bars 31 is attached to the opening / closing mechanism 3
It is opened by 2 and arranged at the receiving position on the conveyor 40 together with the holder 33 (state of the imaginary line on the right side of FIG. 1 and the imaginary line of FIG. 2).

When the belt B comes to the receiving position, that is, the inside of the bar 31, the pair of bars 31 is closed by the opening / closing mechanism 32, and the belt B is fitted and held in the groove portions 31d on the inside (FIG. 2). Of the solid line). At this time, the belt B is securely held and does not rock, and as described above, the belt B has an oval shape that should follow the outside of the pulleys 2U and 2D.

By swinging the swing arm 36 by expanding and contracting the air cylinder 36b of the moving mechanism 34,
The pulley 2U moved by moving the holding tool 33 and brought into the approaching state.
Carry belt B to the outside of 2D (see phantom line in FIG. 2 or upper part in FIG. 4). At this time, since the belt B has an elliptical shape as described above and can be moved together with the holder 33 and the bar 31 without changing the direction, the pulley 2U
-Smoothly carried to the outside of 2D. If the pulleys 2U and 2D are not ready, the vehicle may be stopped once at a waiting position (a solid line position in the middle of FIG. 4).

Until the pulley 2D descends to a predetermined position, the holder 33, the bar 31 and the like are kept in the above-mentioned destination as they are, but the tension is applied to the belt B by opening the pulleys 2U and 2D. Bar 31
It is opened by the opening / closing mechanism 32 and separated from the belt B.
With 3, etc., the moving mechanism 34 returns to the original standby position or belt receiving position. Pull away from the bar 31, 2U
The belt B, to which a predetermined tension is applied on 2D, includes the rollers 3 and 3a and the detection device 1 in the cover winding machine 1.
The cover cloth A is wound by the action of 0 or the like. The belt B whose cover has been wound is removed from the pulleys 2U and 2D by the pushing-out means (not shown) in the cover winder 1 after the pulleys 2U and 2D come close to each other again.

Although one embodiment has been introduced above, the belt hanging device of the present invention is not limited to the above example. For example, the following implementations are possible.

(A) The pair of rods (clamp bars) for holding the belt do not necessarily have to be substantially parallel to each other in the closed state as shown in FIG.
It suffices for each bar to be approximately parallel to any of the common tangents between the pulleys on which the belt is hung. As an example, the case shown in FIG. 5 can be considered. That is, the three pulleys 52L, 52M, 52R for hanging the belt B are
As shown in the figure, when the belts B are arranged sideways (substantially horizontally) in the shape of a long triangle and the tension is applied to the belt B by the movement of any one of them, the clamp bar 61 is closed. Should be substantially parallel to the common tangent line between the pulleys 52M and 52R and between the pulleys 52L and 52R. At this time, the belt B is not deformed into an oval shape, but is deformed into a diaper shape, and is held between the bars 61.

(B) To connect the holder and the fixing member (frame) for the purpose of pivotally moving the holder without changing the direction, use the toothed pulleys 38a and 38b and the synchro belt 38c as shown in FIG. It is also possible by other than.
For example, the pulleys 38a and 38b in FIG. 3 may be replaced with gears (having the same number of teeth), and an odd number of gears (rotatably attached to the swing arm 36) may be interposed therebetween. Alternatively, the belting device 70 of FIG.
As described above, one point on the holder 73 and one point on the frame 75 may be connected by a connecting rod 78 having a constant size. Figure 6
Also in such a case, when the swing arm 76 pivots around the base portion 76a, the holder 73 having the clamp bar 71 rotates in the opposite direction around the support shaft 77 by the same angle as the pivot angle of the arm 76. , Keep the orientation of the whole unchanged.

(C) In the device of the invention, the belt is sandwiched and held by the pair of rods instead of being hung, so that the pulley to be hung may be arranged horizontally as shown in FIG. Moreover, in FIG. 5, the directions of the rods (arms 61) are associated with each other regardless of whether the pulley shafts are horizontal or vertical (upward / downward). The belt can be securely hung between the pulleys. Further, since the swing surface of the swing arm is not limited to the horizontal surface as in the example of FIGS. 1 to 4, it is also possible to transport the belt to the pulley while changing the height. For example, in the example of FIG. 6, the swing surface of the swing arm is vertical.

It is needless to say that the purpose of hanging the belt around the pulley is not limited to winding the cover around the belt. The device of the present invention is widely useful when belts must be looped between the same pulleys a number of times in various manufacturing processes, inspection processes, or use stages.

[0042]

According to the belt hanging device of the present invention, 1) the transmission belt can be reliably and accurately reached to the optimum position around the pulleys regardless of the arrangement of the pulleys (arrangement of a plurality of pulleys and the direction of its axis). 2) It can be carried, and even a transmission belt with a shorter circumference than the pulley diameter can be automatically hung on the pulley.

According to the apparatus of claim 2, 3) the moving mechanism can be constructed relatively easily, and 4) related facilities can be efficiently and compactly arranged.

[Brief description of drawings]

FIG. 1 is a belt hanging device 30 according to an embodiment of the present invention.
It is a front view which shows the cover winding machine 1 containing such as.

FIG. 2 is a front view showing a part of a belt hanging device 30.

3 is a side view of the belt hanging device 30 and the belt supply conveyor 40, which is a view taken along the line III-III in FIG.

FIG. 4 is a plan view of the belt hanging device 30 shown in FIG.
It is a IV-IV arrow line view.

FIG. 5 is an explanatory view showing a part of a belt hanging device according to another embodiment together with a pulley and the like.

FIG. 6 is a belt hanging device 70 as still another embodiment.
FIG.

[Explanation of symbols]

 B Belt 1 Cover winder 2U / 2D / 52L / 52M / 52R Pulley 30/70 Belt hooking device 31/61/71 Clamp bar (bar) 32 Opening / closing mechanism 33/73 Holding device 34/74 Moving mechanism 35/75 Frame ( Fixed member) 36/76 Swing arm 37/77 Support shaft

Claims (2)

[Claims] 1. A device for hanging a transmission belt between a plurality of pulleys whose mutual positional relationship is variable from an approaching state, the device comprising: a) a pair of rods having a groove into which the belt can be fitted, the groove being inside in the longitudinal direction. B) Opening / closing mechanism for opening / closing the pair of rods between a position close to the common tangent line of the pulleys in the approaching state and substantially parallel to each other, and a position having a distance larger than that, c) Opening / closing of the rods A belt hooking device incorporating a holder to which the mechanism is attached, and d) a moving mechanism that moves the holder from a belt receiving position to a position outside the pulley. 2. As the moving mechanism, a swing arm is rotatably provided with respect to a fixed member, and the holder is rotatably attached to a tip end of the swing arm via a support shaft perpendicular to a turning surface of the arm. The belt hooking device according to claim 1, wherein the holding member is connected to the holding member such that the holding member rotates in the opposite direction at the same angle as the turning angle of the arm.