JPH0138247B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is used in a hoisting type cargo handling machine such as a crane that drives a hoisting drum to wind up or unwind a pair of ropes to raise and lower a suspended load. This invention relates to an improvement of a hanging load detection device.

BACKGROUND ART Measuring the weight of a lifted load using a cargo handling machine such as a crane that lifts and transports loads is important not only for measurement management but also for safety. Therefore, as shown in Fig. 1, conventionally, load detectors are installed at hook part 1, upper sheave part,
Alternatively, measurements were carried out by incorporating it into the equalizer sheave section 5 or the like. Conventionally, many of the load detectors described above are of a type that detects compressive strain of a sensing portion that detects a load.

By the way, in a load detector that detects compressive strain in the sensitive part, in order to increase the load detection sensitivity, it is necessary to increase the size (height) of the sensitive part that receives compressive strain.
It is necessary to make the sensing area large, and the sensing part usually has a convex spherical shape. For this reason, conventional load detectors are point-supported, and in order to incorporate such a load detector into a hoisting type cargo handling machine as described above, a bearing on one end of the rope hoisting drum and a bearing on one end of the rope hoisting drum are required. A plurality of load detectors must be disposed between the supporting stand and the stand. With such a device, the structure is complicated and it is difficult to assemble the load detector, and the vertical dimensions of the load detector itself are large, so installing the detector requires a reduction in the lifting height of the crane. The drawback was that the range of movement of the crane had to be sacrificed.

The present invention has been made in order to eliminate such conventional drawbacks, and is a hoisting type cargo handling machine that has small dimensions in the vertical direction, does not cause lift loss, and can extremely easily attach a load detection section. The purpose of the present invention is to provide a load detection device.

Therefore, the first invention of the present application is a hoisting type in which a suspended load is supported and moved by a pair of ropes wound symmetrically around a rope hoisting drum supported by bearings at both ends. In the cargo handling machine, the center of the bearing is located between the bearing mounting surface of a stand that is disposed under the bearing on one end side of the rope hoisting drum and supports the bearing on the one end side and the bearing bottom surface of the bearing on the one end side. A block-shaped detection base is interposed so as to be symmetrical with respect to a line, and the lower surface of the block-shaped detection base facing the bearing mounting surface extends over an area exceeding the dimension of the bottom surface of the bearing in the left-right direction, leaving both ends thereof. The block-shaped detection base has a center portion in the thickness direction of a portion that is symmetrical with respect to the center line of the bearing and has a space between the base and the bearing mounting surface. Strain detectors are installed at two central positions on the neutral axis that extends beyond the dimension of the bearing mounting surface of the part having the above-mentioned intermediate part, respectively, to detect the suspended load. It is a feature.

Further, the second invention of the present application is a hoisting type cargo handling system in which a suspended load is supported and moved by a pair of ropes wound symmetrically around a rope hoisting drum supported by bearings at both ends. In the machine, there is a center line of the bearing between the bearing mounting surface of the stand that is disposed under the bearing on one end side of the rope hoisting drum and supports the bearing on the one end side and the bearing bottom surface of the bearing on the one end side. A block-shaped detection base is interposed so as to be symmetrical with respect to the bearing surface, and the lower surface of the block-shaped detection base facing the bearing mounting surface extends over an area exceeding the dimension of the bottom surface of the bearing in the left-right direction except for both ends thereof. Between the above bearing mounting surface〓
The block-shaped detection base has a portion that is symmetrical about the center line of the bearing and has a portion between the block-shaped detection base and a neutral axis passing through the center in the thickness direction of the portion. A pair of detection parts each having a pair of opposing surfaces are provided at two central positions on both ends exceeding the dimensions of the bearing mounting surface of the part having the part, and a strain gauge that intersects on the neutral axis is pasted on each opposing surface. By combining these four pairs of strain gauges, the shear strain generated at both ends of the above-mentioned intermediate portion of the block-shaped detection base due to the downward force acting from the bearing and the upward force acting from the bearing mounting surface is detected. The present invention is characterized in that a Wheatstone bridge circuit is configured to detect the load, and the suspended load is detected from the output of the Wheatstone bridge circuit.

Hereinafter, the present invention will be described in more detail based on illustrated embodiments.

In FIG. 1, the weight of a load 2 suspended from a hook 1 is normally supported by a rope 4 wound around a hoisting drum 3 and a rope 6 suspended from an upper sheave or equalizer sheave 5. Ru.

Therefore, the rope 4 wound around the hoisting drum 3
By measuring the tension T acting on the load 2
The weight of can be measured. The present invention provides a crane scale that measures the tension T of the rope 4 and the weight of the cargo 2.

FIG. 2 shows a plan view of the winding mechanism, and FIG. 3 shows a side view of the winding drum.

In FIG. 2, the hoisting drum 3 is rotated at one end by a motor 7 via a coupling 8 and a reduction gear 9, and the other end is supported by a bearing 11 provided on a stand 10.

As shown in FIGS. 2 and 3, the rope 4 is usually composed of two ropes, each having a reverse thread, so that the center of gravity remains unchanged as the hoisting drum 3 rotates. Therefore, the bearing 1 of the hoisting drum 3
A load T/2, which is 1/2 of the tension T caused by the weight of the load 2, is applied to the hook 1 regardless of the position of the hook 1.

Therefore, by detecting the load acting on this bearing 11, the weight of the cargo 2 can be measured.

The bearing 11 and the stand 10 are usually joined in a plane and bolted together. Therefore, as shown in FIG. 3, by installing a block-shaped detection base 12 having parallel upper and lower planes between the bottom surface of the bearing 11 and the bearing mounting surface of the stand 10, the weight of the cargo 2 can be reduced. It becomes possible to measure. FIG. 4 is a front view of the mounting part of the block-shaped detection base 12, and FIG.
The figure shows a plan view of the block-shaped detection substrate 12, and FIG. 6 shows a cross-sectional view.

The block-shaped detection base 12 has a lower surface that comes into contact with the bearing mounting surface of the stand 10, which extends over an area exceeding the dimension of the bearing bottom surface in the left-right direction in FIG. It has an interval g. The block-shaped detection substrate 12
is interposed between the bottom surface of the bearing 11 on one end side of the rope hoisting drum 3 (see FIG. 2) and the bearing mounting surface of the stand 10 so as to be symmetrical with respect to the center line of the bearing 11. be done. That is, the left and right flange portions 11a, 11a' of the bearing 11 are attached to the upper surface 13 of the block-shaped detection base 12, and the width direction of the left and right flange portions 11a, 11a' of the bearing 11 is aligned with the longitudinal center line G of this upper surface 13. The joints 15, 15' are fixed with bolts 14, 14' with their center lines aligned, and the joint parts 15, 15' provided at both left and right ends of the portion g between the lower surface of the block-shaped detection base 12 are aligned with the center line of the bearing 11 on the stand 10. It is secured with bolts 16, 16' at its symmetrical ends. The load acting on the bearing 11 is transmitted to the stand 10 through the block-shaped detection base 12 at the joint portions 15, 15' with the stand 10; The hatched portions 19, 19' (shear stress areas) between the inner ends 18, 18' of the load detector joint parts 15, 15', which exceed the dimensions of the bearing mounting surface, and the joint parts 15, 15'. The portions not in contact with 15, 15' receive shearing force due to the downward force from the bearing 11 and the support reaction force from the stand 10, and generate shearing stress. By providing a means for detecting this shear stress, a compact load detector can be easily obtained. As the detecting means, a strain detecting body, particularly a strain gauge is preferable. An example using a strain gauge will be described below. That is, strain gauges 21, 22, 23, 24, 2 are bonded to vertical circular holes 20, 20' provided on the longitudinal center line G of the block-shaped detection base 12 in the shear stress portions 19, 19'.
5, 26, 27, and 28 form a Wheatstone bridge circuit 29 as shown in FIG. 7 to detect the shear stress generated in the shear stress portions 19, 19'.

As shown in FIGS. 5 and 6, each pair of strain gauges 21, 22, 23, 24, 25,
26, 27, 28 are provided on a pair of opposing surfaces facing each other across the longitudinal center line G of each hole 20, 20'.
45 with respect to the neutral axis N passing through the center in the thickness direction of the part having the section g between the block-shaped detection substrates 12, that is, the axis defined by connecting the centroids of the vertical sections of the section. They are attached at an angle of 90° and intersect with each other at each angle of 90°.
These strain gauges 21, . . . , 28 are connected in series for each pair of strain gauges to form the Wheatstone bridge circuit 29. If the Wheatstone bridge circuit 29 having such a combination structure is used, the output voltage
Eout is proportional to the shearing force acting on the shearing stress portions 19, 19', and this shearing force is naturally proportional to the tension T of the rope 4 acting on the bearing 11. The weight of the suspended load 2, that is, the suspended load can be detected.

As is clear from the above description, the first invention of the present application includes a block-shaped detection base having parallel horizontal upper and lower surfaces interposed between the bearing at one end of the hoisting drum and the bearing mounting surface. The present invention provides a suspended load detection device for a hoisting type cargo handling machine, which detects a suspended load load by providing a strain detection body on a shape detection base.

Further, the second invention of the present application is such that a block-shaped detection base having parallel horizontal upper and lower surfaces is interposed between the bearing at one end of the hoisting drum and the bearing mounting surface, and the upper and lower sides act on the block-shaped detection base. The object of the present invention is to provide a suspended load detection device for a hoisting type cargo handling machine, which has a Wheatstone bridge circuit consisting of a pairwise combination of a total of eight strain gauges that detect directional shearing force.

According to the first invention of the present application, since the load detection section is constituted by a low-height block-shaped detection base, there is no lifting head loss of the hoisting type cargo handling machine, and moreover, one end of the rope hoisting drum The load detection section can be incorporated simply by interposing a block-shaped detection base between the bottom surface of the bearing and the mounting surface of the bearing.

Further, according to the second invention of the present application, the first invention of the present application
In addition to the effects of the above invention, the load of a suspended load can be electrically detected accurately and easily by a Wheatstone bridge circuit configured by a pairwise combination of strain gauges.

[Brief explanation of drawings]

Fig. 1 is an overall schematic diagram showing an example of a crane device, Fig. 2 is a plan view of the hoisting mechanism of the crane device, Fig. 3 is a side view of the hoisting drum, and Fig. 4 is a block-shaped detection base. FIG. 5 is a plan view of the block-shaped detection base, FIG. 6 is a longitudinal cross-sectional view, and FIG. 7 is a circuit diagram of the Wheatstone bridge circuit according to the present invention. be. 3...Hoisting drum, 4...Rope, 10...Stand, 11...Bearing, 12...Block-shaped detection base, 13, 13'...Top surface, 15, 15'...Bottom surface, 19, 19' ...Shear stress part, 20,2
0'...hole, 21-28...strain gauge,
29...Wheatstone bridge circuit.

Claims (1)

[Scope of Claims] 1. A hoisting type cargo handling machine in which a suspended load is supported and moved by a pair of ropes 4 wound symmetrically around a rope hoisting drum 3 supported by bearings at both ends. , the bearing mounting surface of the stand 10 that is disposed under the bearing 11 on one end side of the rope hoisting drum 3 and supports the bearing 11 on the one end side, and the bearing 1 on the one end side.
A block-shaped detection base 1 is arranged symmetrically with respect to the center line of the bearing 11 between the bottom surface of the bearing 1 and the bottom surface of the bearing 1.
2 is interposed, and the lower surface of the block-shaped detection base 12 facing the bearing mounting surface has a space between it and the bearing mounting surface over an area exceeding the dimension of the bottom surface of the bearing in the left and right direction, leaving both ends thereof. 〓Has part g,
The block-shaped detection base 12 is symmetrical with respect to the center line of the bearing 11 and has an intermediate portion located on a neutral axis passing through the center in the thickness direction of a portion having an intermediate portion of the block-shaped detection base 12. 2, which is the center of both ends that exceed the dimensions of the bearing mounting surface of the part.
A suspended load detection device for a hoisting type cargo handling machine, characterized in that strain detectors are provided at positions 19 and 19' to detect a suspended load load. 2. In a hoisting type cargo handling machine in which a suspended load is suspended and moved by a pair of ropes 4 wound symmetrically around a rope hoisting drum 3 supported by bearings at both ends, the above-mentioned rope hoisting The bearing mounting surface of the stand 10 that is disposed under the bearing 11 on one end side of the drum 3 and supports the bearing 11 on the one end side, and the bearing 1 on the one end side.
A block-shaped detection base 1 is arranged symmetrically with respect to the center line of the bearing 11 between the bottom surface of the bearing 1 and the bottom surface of the bearing 1.
2 is interposed, and the lower surface of the block-shaped detection base 12 facing the bearing mounting surface has a space between it and the bearing mounting surface over an area exceeding the dimension of the bottom surface of the bearing in the left and right direction, leaving both ends thereof. 〓Has part g,
The block-shaped detection base 12 has a neutral axis that is symmetrical with respect to the center line of the bearing 11 and passes through the center in the thickness direction of a portion of the block-shaped detection base 12 that has a portion between them. A pair of detection parts each having a pair of opposing surfaces are provided at two central positions 19 and 19' of both ends exceeding the dimensions of the bearing mounting surface of the part, each of which has a strain gauge intersecting on the neutral axis. 21 to 28, and by combining these four pairs of strain gauges 21 to 28, the block-shaped detection base 12 is controlled by the downward force acting from the bearing 11 and the upward force acting from the bearing mounting surface. A Wheatstone bridge circuit is configured to detect the shear strain occurring at both ends of the portion g, and the Wheatstone bridge circuit 29
A suspended load detection device for a hoisting type cargo handling machine, characterized in that a suspended load is detected from the output of the hoisting type cargo handling machine.