JPS6238276B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crane in which a gripping device is supported at the tip of the working device.

First, an example of a conventional mobile crane of this type will be explained with reference to FIG.

An upper revolving body 2 is rotatably mounted on the upper part of the traveling body 1, and a driver's cab 3 is installed in the front part of the upper revolving body 2, and a working device 4 is attached thereto. The working device 4 includes a boom 4a attached to the upper revolving structure 2 so as to be able to rise and fall, and an arm 4 that is swingably supported at the tip of the boom 4a.
c. Boom cylinder 4 that raises and lowers the boom 4a
b, arm cylinder 4d that swings the arm 4c;
A gripping device (for example, a wood gripping device) 5 is suspended from the tip of the arm 4c via a link 7 and a load cell 6 for detecting a hanging load. The proximal end of the boom cylinder 4b is supported by the upper revolving body 2, and the tip of its piston rod is connected to the intermediate portion of the boom 4a. The base end of the arm cylinder 4d is supported by the upper middle part of the boom, and the tip of its piston rod is connected to the base end of the arm 4c.

In this mobile crane, the gripping device 5 is always suspended vertically, so by operating a lever inside the operator's cab 3, the workpiece (for example, wood) directly below the gripping device 5 can be gripped only from the direction of gravity. In addition, both the load cell 6 and the gripping device 5 must be lifted and suspended while rotating and moving to carry out the work. That is, in a plane including the work device 4, grip device 5, etc., it is not possible to grasp the work object at an angle other than the direction of gravity, and it is impossible to lift, hang, or turn the object while grasping it. If in-plane movement is not possible, the gripping device 5 may be suspended, especially when leveling or rearranging workpieces piled up, or loading workpieces onto a dump truck. Since the work can only be carried out in this state, the work must be carried out with the object under the gripping device 5, requiring a crane with a large working radius, and the work must be moved horizontally.
It is not possible to perform so-called pushing, pulling, or lateral pushing operations, making it impossible to increase work efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide a crane that can perform work while holding a gripping device at an angle other than vertical, and can accurately detect a load regardless of the position of the gripping device. It is something.

In order to achieve the above object, the present invention supports a horizontal axis perpendicular to the longitudinal direction of the arm via a bearing at the tip of the arm constituting the working device,
A gripping device is swingably suspended from the protrusion of the horizontal shaft, and a couple link is supported swingably in the longitudinal direction of the arm at a location on the arm in front of the horizontal shaft, and both ends of the couple link are and the corresponding connecting portion of the gripping device are connected by a parallel link, one end of an operating cylinder supported on the upper side of the arm is connected to a connecting pin between the parallel link and the couple link, and the bearing and the horizontal shaft are connected. A load cell is installed integrally with the shaft between the lower parts of the horizontal shaft, a weight is attached to the end of the horizontal shaft, and the direction of the center of gravity of the weight is aligned with the direction of the load cell. It is characterized by

Next, one embodiment of the present invention will be explained with reference to FIGS. 2 to 7. In these figures, the same reference numerals as in FIG. 1 represent the same or equivalent items.

A cylindrical part is provided at the tip of the arm 4c so as to be orthogonal to the longitudinal direction of the arm 4c, and the cylindrical part has a horizontal shaft for hanging (hereinafter referred to as the shaft) with an end protruding outward. )8 is supported. That is, a bearing 9 is installed inside the cylindrical portion, and an annular body 10 is supported on the inner ring thereof. A square hole is provided in the center of the annular body 10,
The square hole is fitted into a square portion 8a formed on the shaft 8. A recess is provided at the bottom of the square hole of the annular body 10, and a load detector (load meter) 11 is attached to the recess, the operating part of which is in contact with the lower surface of the square part 8a. That is, the load detector 11 is installed integrally with the horizontal shaft 8 between the bearing 9 and the lower side of the horizontal shaft 8. A bearing retainer 12 is fixed to the outer end surface of the cylindrical portion of the arm 4c,
A stopper 13 is fixed to the outer surface of the annular body 10. A cable 11a of the load detector 11 is led out from a hole provided in the stopper 13.

A hanging portion of the gripping device 5 is rotatably supported at the end of the shaft 8 via a pillow block 14 having a built-in bearing. A weight (hereinafter referred to as weight) 15 is fixed integrally.

A pin 16 is attached to a portion of the arm 4c in front of the shaft 8, and the center portion of a couple link 17 is fitted into the protruding end portions at both ends of the pin 16, respectively. The couple link 17 can swing in the longitudinal direction of the arm 4c around the pin 16, and has pins 18A and 18 at its ends, respectively.
One end portions of parallel links 19 and 20 are connected via B. The other ends of the parallel links 19 and 20 are connected to the gripping device 5 via pins 21A and 21B, respectively.
It is connected to the connecting part of. Pins 21A, 21B
are positioned so that a parallel linkage is formed. A hydraulic cylinder 22 is installed on the upper side of the arm 4c, and the tip of its piston rod is connected to the pin 18A.

In FIG. 2, A shows the gripping device 5 in a vertical position. When lowering the gripping device 5 from position A to positions B and C shown by two-dot chain lines while maintaining the vertical state, the hydraulic cylinder 2 is moved while extending the arm cylinder 4d and lowering the arm 4c.
Shorten 2. In this case, the boom cylinder 4b
Of course, it is also possible to operate the boom 4a by expanding and contracting it to combine rotation of the boom 4a. When raising the grip device 5 from position A to horizontal position D,
The hydraulic cylinder 22 is shortened and the gripping device 5 is rotated counterclockwise around the hanging pin 8.

When the hydraulic cylinder 22 is shortened, the pin 18A
The tensile force acting on pin 18 acts as a couple centered on pin 16, which is the central fulcrum of couple link 17.
It acts on pin 18B on the symmetrical side of A. Therefore, the couple link 17 is the second link with the pin 16 as the center.
Rotates counterclockwise in the figure, and at the same time,
The parallel link 19 is pulled in the direction of the hydraulic cylinder 22, and the parallel link 20 moves in the direction of pushing out the gripping device 5. Due to this operation, the gripping device 5 rotates counterclockwise around the shaft 8, and the second
The state D indicated by the two-dot chain line in the figure or the state shown in FIG. 3 can be achieved.

Here, with reference to FIGS. 6 and 7, the balance of forces when the gripping device 5 rotates will be explained.

FIG. 6 shows a position G ₁ where the center of gravity of the gripping device 5 is in a vertical state (the position indicated by the solid line in FIG. 2) by a horizontal distance l ₁ by rotation of the gripping device 5 in the counterclockwise direction. Indicates the case where you move to . l ₁ represents the distance from the center of the hanging pin 8, which is the center of rotation of the grip device 5, to the center of gravity G ₁ . When a load W, which is the sum of the weight of the shaft ₈ , the gripping device 5, the pillow block 14, and the weight 15 and the hanging load, acts vertically on the center of gravity G1, a clockwise rotational moment W· _l1 is generated. This moment causes the couple link 17 to move through the parallel links 19 and 20 to the pin 16.
Try to rotate in the same direction around . If the normal distance between the parallel links 19 and 20 is l ₁ , counterclockwise moments H ₁ · l ₂ and H' ₁ · l ₂ counterclockwise and balanced against the rotational moment are generated with the pin 16 as the center. It becomes necessary. Here, the force H ₁ on the pin 18A and the force H' ₁ on the pin 18B are equal, and the directions of the forces are opposite and parallel to each other. Therefore, W·l ₁ =H ₁ ·l ₂ or H' ₁ ·l ₁ , and when W·l ₁ <H ₁ ·l ₂ , the gripping device 5 rotates counterclockwise. Further, H ₁ is divided into a force T ₁ in the direction of the hydraulic cylinder 22 and a force V ₁ in the direction of the couple link 17 at the position of the pin 18A. In this case, W is directly supported in the vertical direction only on the shaft 8, which is the center of rotation of the gripping device 5. A component force V ₁ acts on pin 16 .

In FIG. 7, the gripping device 5 has rotated further counterclockwise than in the state shown in FIG. 6, and the horizontal distance from the center of the shaft 8 to the center of gravity _G2 of the gripping device 5 has changed from _l1 to l' _1.
It shows an increased state. In this case, the hydraulic cylinder 22 is further shortened, and the normal distance between the parallel links 19, 20 is also reduced from _l2 to l' ₂ . The moment balance at this time is W・l′ ₁ =
H ₂ or H′ ₂・l′ ₂ . Here H ₂ is pin 18A
The force on the pin 18B, _H'2 , is the force on the pin 18B. Also, _H2 is the hydraulic cylinder 22 at the pin 18A position.
It is divided into a force T ₂ in the direction of , and a force V ₂ in the direction of the couple link 17 . The gripping device 5 changes from the state shown in FIG. 6 to the state shown in FIG.
When it rotates to the state shown in the figure, it changes from [l ₁ <l' ₁ , l ₂ >l' ₂ ] to [H ₁ < H ₁ , T ₁ < T ₂ ], but in this case as well, the load W is 8, it is supported as it is in the vertical direction. Component force V ₂ is pin 16
It acts on

With the above-mentioned configuration, the gripping device 5 can freely rotate in the plane, but when the gripping device 5 is rotated in a pushing direction, the load W is pushed outward by that much compared to when it is in the vertical state. , the moment applied to the entire crane increases, resulting in overload. In addition, it is necessary to prevent overload so that the crane does not lift a load (overload) larger than the allowable lifting load. In order to prevent this overload, it is necessary to detect the vertical load applied to the shaft 8 regardless of the position of the gripping device 5, and a load detector 11 for detecting this is installed under the square portion 8a of the shaft 8. It's crowded. This assembly position is
This is the same position as the load cell 6 attached to the tip of the arm 4a in FIG. And in this position,
Since the load W always acts as it is in the vertical direction, even if the gripping device 5 rotates, the load W at the rotation position can be accurately detected. That is, weight 15
Since it always hangs down in the direction of gravity together with the real shaft 8, the load detector 11 is also held at the set position independently of the gripping device 5. Therefore, the shaft 8, the gripping device 5, the pillow block 14, the weight 15 and the suspended load act on the load detector 11 as a load W in the direction of gravity. The load W detected by the load detector 11 is transmitted to the working device 4 through the annular body 10 and the bearing 9.

In order to reliably transmit the force of the couple link 17 to the parallel link, FIG. The cylinder chambers of both cylinders 23 and 24 are connected by piping 25 and 26, respectively, and the cylinder chambers of both cylinders 23 and 24 and piping 25 and 2
6 shows another embodiment of the present invention in which hydraulic oil is sealed. In this figure, the same reference numerals as in FIGS. 2 to 7 represent the same parts. The base ends of the cylinders 23 and 24 are provided with pins 18A and 18, respectively.
The piston rods on the opposite side of the pins 18A and 18B are connected to pins 21A and 21B, respectively. The rest is the same as the embodiment described above.

Figure 9 shows a rod-type double-acting cylinder 23, 2 on both sides.
4, a pin hole 27 is provided at the proximal end thereof, and a pin hole 28 is provided at the end of the piston rod opposite to the proximal end.

In the previously described embodiment, the couple link 17
If there is a gap between the pins 18A, 18B attached to the pin holes and the pin holes, the couple link 17
Even if the gripping device 5 rotates to transmit force, the force is not transmitted to any of the parallel links, and the gripping device 5 is rotated only by the parallel link on one side.
On the other hand, in the embodiment shown in FIG. 8, the operation of the parallel link mechanism is ensured by movement of the hydraulic oil in the cylinder chambers of the double-acting cylinders 23 and 24 as the couple link 17 rotates. It will be held on.

According to the invention described above, the gripping device can be swung at any angle in the longitudinal direction of the arm, and work can be performed while accurately detecting the suspended load at any swiveling position. , it is possible to improve work efficiency and safety, and to manufacture a gripping device at a low cost. Furthermore, if this invention is applied to a backhoe, it can be used as a crane in the same way as before.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a crane equipped with a conventional gripping device, Fig. 2 is a side view showing an embodiment of the present invention, and Fig. 3 is a counterclockwise rotation of the gripping device in Fig. 2. An enlarged side view showing the state, Fig. 4 is an enlarged cross-sectional view of Fig. 3, and Fig. 5 is an enlarged cross-sectional view of Fig. 4.
6 and 7 are explanatory diagrams illustrating the force relationship during rotation of the gripping device according to the present invention, and FIG. 8 is a side view showing another embodiment of the gripping device according to the present invention. 9 is an enlarged detailed cross-sectional side view showing the double-acting double-acting cylinder shown in FIG. 8. 1... Traveling body, 2... Upper rotating body, 4... Working device, 4c... Arm, 4d... Arm cylinder, 5... Gripping device, 8... Hanging shaft,
8a... Square part, 9... Bearing, 10... Annular body, 11... Load detector, 13... Stopper, 1
4... Pillow block, 15... Weight, 16...
...Pin, 17... Couple link, 18A, 18B...
...Pin, 19,20...Parallel link, 21A,2
1B...Pin, 22...Hydraulic cylinder, 23,2
4...Rod type double acting cylinder on both sides, 25, 26
……Piping.

Claims (1)

[Scope of Claims] 1. A horizontal shaft perpendicular to the longitudinal direction of the arm is supported via a bearing at the tip of the arm constituting the working device, and the gripping device is swingably suspended from the protrusion of the horizontal shaft. A couple link is supported swingably in the longitudinal direction of the arm at a location on the arm in front of the horizontal axis, and both ends of the couple link and the corresponding connection part of the gripping device are connected by a parallel link. One end of the operating cylinder supported on the upper side of the arm is connected to a connecting pin between the parallel link and the couple link, and a load meter is installed integrally with the shaft between the bearing and the lower side of the horizontal shaft. A gripping device characterized in that a weight is attached to an end of the horizontal shaft, and the direction of the center of gravity of the weight is aligned with the direction of the load meter. 2 The parallel link is formed by rod-type double-acting cylinders on both sides, and the cylinder chambers on opposite sides of both double-acting cylinders are connected by piping, and hydraulic oil is sealed in the cylinder chambers and piping of both double-acting cylinders. A crane according to claim 1.