JP7098403B2 - Safety management system for loading and unloading work - Google Patents

Description

The present invention relates to a safety management system for lifting heavy objects such as bridge girders.

At construction sites and factory facilities, cranes may be used to lift and move loads such as equipment using cables. Generally, when the suspended load is medium-sized or large-sized, the suspended load is suspended at multiple points. At this time, it is desirable that tension is applied to each cable in a well-balanced manner. This is because the suspended load may be tilted or the cable may be broken.

As one method for equalizing the load acting on the cable that suspends the load, it is conceivable to construct a safety management system that measures and displays the load acting on the cable. As an example of such a safety management system, Patent Document 1 describes that a strain gauge is attached to a shackle on which a wire rope is fastened, and the amount of strain of the shackle itself due to a tensile load acting on the shackle is detected. It is disclosed to measure and display the tension acting on the wire rope.

Japanese Unexamined Patent Publication No. 7-291577

However, in the safety management system described in Patent Document 1, since only one strain gauge is attached to the shackle, accurate tension cannot be measured depending on how the load is applied to the shackle, and the load is on the level of several tons. If it becomes heavy and the shackle becomes large, the tension of the cable may not be measured accurately.

The present invention has been made in view of the above circumstances. That is, the problem is to provide a safety management system with high accuracy and versatility of the measured load.

One embodiment of the present invention made to solve the above problems acts on each hanger interposed between each of the plurality of cables and the load when the load is hung by a crane using a plurality of cables. A safety management system in a load-lifting operation that calculates a load to be applied, wherein the crane has a pair of side portions that are parallel to each other at a distance from each other, and is arranged on at least one of the pair of side portions. Based on the detection means that detects the strain along the axis of both surfaces facing each other across the axis of the section and the strain information detected by the detection means, the load acting on the crane is calculated for each crane. It is characterized in that it is provided with a calculation means for performing.

Since the detecting means detects the strain along the axis of both surfaces facing each other across the axis of the side, the load acting on each hanger is calculated more accurately and the load is displayed on a predetermined display unit. be able to. As the weight of the load increases, the diameter of the side portion of the hanger used for the load suspension work increases, and the difference in strain between the two surfaces facing each other across the axis of the side portion tends to increase accordingly. This is especially effective when the load of the suspended load is several tons or more. That is, the versatility of the safety management system is improved.

In the safety management system in the above-mentioned loading and unloading work, both surfaces, which are the detection points of the detection means, may be the front surface and the rear surface of the side portion. When the hanger receives a tensile load, a bending load acts on the side surface, and the strain on the outer surface and the strain on the inner surface of the side surface vary. Therefore, the accuracy of the load acting on the hanger can be improved by measuring the strain on the front surface and the rear surface of the side portion. The front surface of the side portion means both front and rear surfaces when the axial direction of each of the pair of side portions is the vertical direction and the direction in which the pair of side portions are arranged is the left-right direction.

In the safety management system for the above-mentioned loading and unloading work, the detection means may be arranged on any of the pair of side portions. When the hanger receives a load in a direction intersecting the axis of the side portion, the load acting on one side portion and the load acting on the other side portion vary. Therefore, by arranging the detection means on any of the pair of side portions, it is possible to improve the accuracy of the load acting on the hanger calculated by the calculation unit.

The safety management system for the suspended load according to the present invention can improve the accuracy of the load acting on the suspended load to be calculated and also enhance the versatility.

It is a block diagram which functionally represented the safety management system of the lifting work which concerns on 1st Embodiment of this invention. It is explanatory drawing which schematically represented the on-site situation where this system is applied. It is explanatory drawing which shows the specific example of the site situation to which this system is applied. (A) is a front view showing a state in which a strain gauge constituting a detection unit included in the system is attached to a shackle, (B) is a side view of AA of FIG. 4 (A), and (C) is a view. 4 (A) is a sectional view taken along the line BB, and (D) is an end view of the CC cut portion of FIG. 4 (A). It is a block diagram which shows the system schematically. It is a block diagram schematically showing the computer included in the system. This is a specific example in which the load acting on the hanger is displayed on the display unit related to the system. It is explanatory drawing which shows the modification example of the concrete example of the site situation to which this system is applied.

First, the safety management system 10 in the loading and unloading work constituting the first embodiment according to the safety management system for the loading and unloading work of the present invention will be described. The safety management system 10 mainly detects and detects the strain generated in each hanger connecting each cable and the load when the load consisting of heavy objects such as bridge girders is lifted and moved by a plurality of cables by a crane. The load acting on each hanger is calculated as the tension acting on each cable based on the strain applied, and is displayed on the display.

As shown in FIG. 1, the safety management system 10 has four detection units 11 that detect the strain generated in each hanger, and a load acting on each hanger based on the strain information detected by each detection unit 11. A calculation unit 12 that calculates the tension acting on each cable, a determination unit 13 that determines whether or not the load calculated by the calculation unit 12 is abnormal, and a display unit that displays the load calculated by the calculation unit 12. A warning unit 15 that issues a warning when the determination unit 13 determines that the load is abnormal is provided.

Next, FIGS. 2 and 3 show specific examples of the work situation to which the safety management system 10 is applied. As shown in FIG. 2, a block 9 of a bridge girder having a rectangular shape in a plan view (hereinafter referred to as “bridge girder 9”) is lifted by a mobile crane 8 (hereinafter referred to as “crane 8”). Specifically, lifting jigs 7 for lifting the bridge girder 9 are fixed at four locations at predetermined distances from the center of both edges of the upper surface of the bridge girder 9 in the longitudinal direction to both ends. A cable 6 is connected to the lifting jig 7. Then, the crane 8 lifts the four cables 6.

As will be described later, the location where each lifting jig 7 is arranged corresponds to the load measurement point calculated by the safety management system 10. Therefore, regarding the location where the four lifting jigs 7 are arranged, the location where the lifting jig 7 is arranged on the back right side of the bridge girder 9 when viewed from the crane 8 in FIG. 2 is set as the measurement point 1, and similarly, the front side. The point on the right side is the measurement point 2, the point on the left side on the back side is the measurement point 3, and the point on the left side on the front side is the measurement point 4.

As shown in FIG. 3, four cables 6 are connected to a hook attached to the tip of the hoisting rope of the crane 8. Each cable 6 is formed by connecting a wire rope 5 whose length cannot be adjusted and a chain block 4 whose length can be adjusted at both tips. In FIG. 3, the wire rope 5 is arranged on the crane 8 side, and the chain block 4 is arranged on the lifting jig 7 side.

Further, a relay hanger 3 is connected to the chain block 4. The relay hanger 3 is composed of a bolt / nut type straight type shackle.

The lifting jig 7 is connected to the measuring hanging tool 2 which is the calculation target of the safety management system 10. The measuring hanger 2 is connected to the relay hanger 3. That is, the connected relay hanger 3 and measurement hanger 2 connect the cable 6 and the lifting jig 7. Further, it can be said that the measuring hanger 2 is interposed between the cable 6 and the lifting jig 7. Next, the measuring hanger 2 will be described. In the following, the measuring hanger 2 is simply referred to as a “hanging tool 2”.

As shown in FIG. 4, the hanger 2 is composed of a bolt / nut type straight shackle. That is, the hanger 2 includes a hanger body 20 having a substantially U-shape in front view, a bolt 21 arranged at the tip of the hanger body 20 in the axial direction, and a nut 22 screwed into the bolt 21. ..

The hanger body 20 has a curved elevation-shaped central portion 23 and a pair of side portions 24 that are continuous at both ends of the central portion 23 and are parallel to each other at a distance from each other. Each side portion 24 is composed of a columnar columnar portion 24A continuous with the central portion 23 and an annular annular portion 24B continuous with the columnar portion 24A. An insertion hole 25 into which the bolt 21 is inserted is formed in the annular portion 24B.

A pair of strain gauges 261,262 for detecting strain along the axis X direction of the side portions 24 are arranged at two positions of each of the pair of side portions 24 constituting each hanger 2. Specifically, the pair of strain gauges 261,262 are attached so as to sandwich the side portion 24 around the center of the columnar portion 24A in the X direction of the axis. The pair of strain gauges 261,262 constitute a strain detecting means 26 for detecting strain along the axis X of both surfaces facing each other with the axis X of each side portion 24 interposed therebetween.

The strain gauge 261 is attached to the front surface of the side portion 24. On the other hand, the strain gauge 262 is attached to the rear surface of the side portion 24. Here, the front surface of the side portions 24 is the front side in FIG. 4A when the X direction of each axis of the pair of side portions 24 is the vertical direction and the direction in which the pair of side portions 24 are arranged is the left-right direction. It is the surface of the (front side), and the rear surface of the side portion 24 is the surface of the rear side (back side) of the side portion 24. For convenience of explanation, the front and rear surfaces, as well as the directions such as the vertical direction and the horizontal direction are specified, but these directions are not specified at the time of implementation.

Further, a recess 27 is formed in the place where the strain gauges 261,262 are attached so that the strain gauges 261,262 can be completely accommodated. In the first embodiment, the strain gauges 261,262 are the same as commercially available general foil strain gauges.

Further, each recess 27 is formed so that the bottom portion in the depth direction is flat and the depth thereof is approximately the thickness of the strain gauges 261,262. Then, strain gauges 261,262 are adhered to the bottom of the recess 27 with a predetermined adhesive.

In this way, the four strain gauges 261,262 attached to each hanger 2 constitute the detection unit 11 corresponding to each hanger 2. That is, the strain detecting means 26 provided on each of the pair of side portions 24 of each hanger 2 constitutes one detection unit 11 for one hanger 2. The hanger 2 to which the four strain gauges 261 and 262 constituting the detection unit 11 are attached is referred to as a "strain detection hanger device 1".

When each strain gauge 261,262 detects a strain, it outputs an analog signal corresponding to the strain. That is, each detection unit 11 detects and outputs the strain detected by the four strain gauges 261,262 attached to each hanger 2 as "strain information" for the hanger 2 at the time of measurement. There is.

The strain detected by each strain gauge 261,262 with respect to this "strain information" is referred to as "individual strain information". Therefore, the strain information detected by each detection unit 11 is composed of four individual strain information detected by the strain gauges 261,262 attached to each detection unit 11.

In the first embodiment, since the hanger 2 is connected to each of the four cables 6 and the detection unit 11 is provided for each hanger 2, the safety management system 10 has four detection units 11. Will be there.

Therefore, the four detection units 11 are referred to as a first detection unit 111, a second detection unit 112, a third detection unit 113, and a fourth detection unit 114. The first detection unit 111 corresponds to the above-mentioned measurement point 1. Similarly, the second detection unit 112 to the fourth detection unit 114 correspond to the measurement points 2 to 4.

Next, the safety management device 40 for realizing the calculation unit 12, the determination unit 13, the display unit 14, and the warning unit 15 of the safety management system 10 will be described. As shown in FIG. 5, the safety management device 40 includes an input connector 41, a strain measuring unit 42, a control unit 43, a computer 44, a display 45, and a warning light 46.

The input connector 41, the strain measuring unit 42, the control unit 43, and the computer 44 are housed in a predetermined case 60 and placed together on the upper surface of the bridge girder 9. Further, the display 45 is carried by the operator around the bridge girder 9 and the crane 8. The warning light 46 is installed on the surface of the crane 8.

The input connector 41 has four input terminals. Each input terminal of the input connector 41 is connected to each detection unit 11 via a communication cable 30. Each of the four strain gauges 261 and 262 constituting each detection unit 11 is connected to the input connector 41 in a separate system from each other via the communication cable 30.

The input connector 41 is also connected to the strain measuring unit 42. The strain measuring unit 42 is also connected to the control unit 43. The control unit 43 is also connected to the first communication I / F included in the computer 44 via a predetermined connection cable. Further, the computer 44 is also connected to the display 45 and the warning light 46 via the wireless LAN slave unit 50 capable of communicating with the external device by the second communication I / F included in the computer 44.

From such a connection configuration of the safety management device 40, the safety management device 40 has the following functions. First, the strain information detected by the detection unit 11 is associated with the measurement point and input to the input connector 41. Specifically, each of the individual strain information detected by the strain gauges 261,262 is associated with the installation location in each hanger 2 and input to the input connector 41 as an analog signal. In the following, the information transmission path of strain information from each detection unit 11 to the input connector 41 via the communication cable 30 is also referred to as a “channel”.

The individual strain information input to the input connector 41 is input to the strain measuring unit 42 as an analog signal. When the individual strain information is input, the strain measuring unit 42 converts the individual strain information for four channels into a digital signal every 500 msec, digitizes it, and transmits it to the control unit 43.

The control unit 43 transmits the received individual strain information for the four channels to the computer 44. That is, the individual strain information for four channels digitized by the strain measuring unit 42 is relayed by the control unit 43 and transmitted to the computer 44. Then, when the computer 44 receives the individual strain information for four channels related to each hanger 2, the computer 44 calculates the load acting on each hanger 2 based on the received individual strain information and displays it on the display 45.

Next, the configuration of the computer 44 will be described. As shown in FIG. 6, the computer 44 can perform various calculations and determinations, and can store the acquired data and the calculation results. That is, the computer 44 has a ROM 47 in which programs for performing various operations and determinations are stored, a CPU 48 for executing various programs, and a RAM 49 for storing necessary data.

As a program stored in the computer 44, a load calculation program 471 that calculates the load acting on each hanger 2 based on the strain information detected by the first detection unit 111 to the fourth detection unit 114, and a suspension There is a determination program 472 that determines whether or not the load calculated for each tool 2 exceeds a preset threshold value. The CPU 48 that executes the load calculation program 471 constitutes the calculation unit 12 of the safety management system 10. Further, the CPU 48 that executes the determination program 472 constitutes the determination unit 13 of the safety management system 10.

The CPU 48 executes the load calculation program 471, that is, each time the calculation unit 12 receives the strain information, each hanger is based on the strain information detected by the first detection unit 111 to the fourth detection unit 114. Calculate the load acting on 2.

Specifically, when calculating the load related to each hanger 2, the calculation unit 12 sums the loads corresponding to the four individual strain information constituting the strain information for each hanger 2, and the summed value. Is divided by "2". The sum of the loads acting on each of the pair of side portions 24 constituting each hanger 2 becomes the load related to the hanger 2, and a pair of strain gauges 261 and 262 are attached to each side portion 24 to each side portion. This is because the strain is detected at two points of 24.

The load calculated for each hanger 2 by the calculation unit 12, that is, the tensile force acting on the hanger 2. Then, this tensile force can be regarded as the tension acting on the cable 6 connected to the hanger 2. The calculation unit 12 stores the calculated load in the RAM 49 in association with the measurement point corresponding to the hanger 2 on which the load acts. Further, the calculation unit 12 sequentially stores the calculated values in the RAM 49 for each measurement point in chronological order. Further, the calculation unit 12 calculates the load in a preset unit of load such as “kN (kilonewton)”.

Further, the CPU 48 executes the determination program 472, that is, each time the determination unit 13 calculates the load by the calculation unit 12, the load is, for example, the breaking load of the wire rope 5 with a predetermined safety factor ( For example, it is determined whether or not the threshold value consisting of the value divided by 6) is exceeded. Then, when the determination unit 13 determines that any of the calculated loads exceeds the threshold value, the determination unit 13 activates the warning light 46 which is communication-connected via the wireless LAN slave unit 50 to issue a warning. Emit.

The configuration of the warning light 46 can be appropriately set. Further, although the installation position of the warning light 46 can be appropriately set, it is desirable that the position is easily visible to the operator. In FIG. 5, it is provided on the upper surface of the crane 8 on the traveling direction side. The warning light 46 constitutes the warning unit 15 of the safety management system 10.

Further, when the calculation unit 12 associates the calculated load with the measurement point and stores it in the RAM 49, the calculation unit 12 displays the load on a predetermined display 45 connected via the wireless LAN slave unit 50 in a predetermined format. Can be made to. The display 45 includes a mobile terminal such as a portable personal computer, a tablet, and a smartphone, a desktop personal computer, and the like. The display 45 constitutes the display unit 14 of the safety management system 10.

Predetermined formats for display include numbers, bar graphs, and line graphs. For example, as shown in FIG. 7A, the load can be displayed as a bar graph and numbers for each measurement point corresponding to the hanger 2. In FIG. 7A, the horizontal axis represents the measurement point and the vertical axis represents the load. In this case, the display 45 updates the display content every time the load is calculated by the calculation unit 12, that is, every 500 msec. Since the bar graph showing the load at each measurement point is updated at any time, only the load at that time is displayed on the display 45.

Further, as shown in FIG. 7B, the load for each measurement point corresponding to each hanger 2 can be displayed in time series by a line graph. In FIG. 7B, the horizontal axis represents time and the vertical axis represents load. Also in this case, the calculation unit 12 updates the display content every time the load is calculated. That is, the display 45 displays the history together with the load at that time.

In order to display the load on the display 45, a program for displaying the load calculated by the calculation unit 12 on the display unit 14 in the predetermined format is stored in the portable personal computer or tablet constituting the display 45. Must be.

As described above, according to the safety management system 10 according to the present invention, strains are detected at two points in the axis X direction in each of the pair of side portions 24 constituting each hanger 2, and the detected strains are detected. Since the load acting on each hanger 2 is calculated based on the information, the accuracy of the load acting on the hanger 2 can be improved. In particular, when the safety management system 10 is applied to the work of lifting a heavy object of several tons or more such as a bridge girder as in the first embodiment, the hanger 2 is also increased in size. Then, the variation of the strain tends to increase depending on the location where the strain is detected for each hanger 2, specifically, the location where the strain is detected on each side portion 24. Therefore, it is safe because the accuracy of the load acting on the hanger 2 can be ensured by detecting the strain of each hanger 2 at a total of four locations on both surfaces facing each other across the axis X of each side portion 24. The management system 10 can also be applied to heavy objects such as bridge girders 9. That is, the versatility of the safety management system 10 can be enhanced.

Further, when a tensile load along the axis X of the side portion 24 acts on the hanger 2 provided with the side portions 24 parallel to each other at a predetermined distance, a bending load is applied to the side portion 24, and the outer surface and the inner surface of the side portion 24 are applied. There is a concern that the amount of deformation of the side surface will be different. Therefore, like the safety management system 10, strains along the axes X on the front and rear surfaces of both side portions 24 of each hanger 2 are detected, and the load acting on each hanger 2 based on the detected strain information. By calculating, the accuracy of the load acting on each hanger 2 can be further improved. Further, by disposing the pair of strain gauges 261,262 on the front surface and the rear surface of each hanger 2, it is possible to prevent the strain gauges 261,262 from being caught in the cable 6 connected to the hanger 2. can.

Further, since there is a concern that the load acting on the side portion 24 may differ depending on the arrangement position of the lifting jig 7, the load acting on the lifting tool 2 is only detected by detecting the strain of one side portion 24. The accuracy of is reduced. Therefore, as in the safety management system 10, strains along the axis X of both side portions 24 of each hanger 2 are detected, and the load acting on each hanger 2 is calculated based on the detected strain information. Therefore, the accuracy of the load acting on each hanger 2 can be further improved.

Further, when the determination unit 13 determines that the calculated load acting on the hanger 2 exceeds a predetermined threshold value, the warning light 46 issues a warning, so that the safety for work can be improved. ..

Further, in the safety management system 10, the strain detecting means 26 for detecting the strain on the side portion 24 is composed of strain gauges 261,262. Therefore, preparation / work related to the safety management system 10 becomes easy. Further, the hanger 2 is formed with a recess 27 for attaching the strain gauges 261,262. Since the recess 27 functions to position the strain gauges 261,262, it is possible to reduce the error at the position where the strain gauges 261,262 are attached. Further, since the depth of the recess 27 is equivalent to the thickness of the strain gauges 261,262, the expansion of the cross-sectional defect of the hanger 2 is suppressed as much as possible.

Hereinafter, main modification examples of the safety management system 10 according to the first embodiment of the present invention will be described. In the first embodiment, the application target of the safety management system 10 is the work of lifting and moving the bridge girder 9 outdoors, but the work place may be indoors, and the load to be lifted is also steel material, equipment, and the like. And may be something other than the bridge girder 9 such as a container.

In the first embodiment, four cables 6 are connected to the hook of the crane 8, but as shown in FIG. 8, the suspension balance 82 is connected to the hook of the crane 8 via two wire ropes 81 for the suspension balance. May be connected, and two cables 6 may be connected to each of both ends of the suspension balance 82. By using the suspension balance 82 in this way, it is possible to suppress the difficulty of the lifting work, especially for a load having a shape that is difficult to balance in the lifting work such as a bridge girder 9.

Further, in the first embodiment, four lifting jigs 7 are fixed to the bridge girder 9, the bridge girder 9 is lifted by four cables 6, and the lifting work is performed by so-called "four-point hanging". The number of 7s and the number of cables 6 are not limited to this, and may be appropriately set. For example, 4-point suspension may be changed to 6-point suspension. In the case of 6-point suspension, the number of measuring suspenders 2 is 6, but correspondingly, change to the input connector 41 having 6 or more input terminals, or the above-mentioned input connector 41, strain measuring unit 42, and One more control unit 43 may be provided.

Further, in the first embodiment, the cable 6 is composed of the wire rope 5 and the chain block 4, but it may be composed of only one of them. Further, although the relay hanger 3 is connected to the cable 6, the measurement hanger 2 may be connected to the cable 6. Alternatively, the detection unit 11 may be provided on the relay hanger 3 connected to the hoisting jig 7.

The measuring hanger 2 and the relay hanger 3 are composed of bolt / nut type straight type shackles, but may be composed of other types of shackles such as screw type bow type shackles. Further, the measuring hanger 2 and the relay hanger 3 may be composed of a hanger other than the shackle.

Further, in the first embodiment, the strain gauges 261,262 are attached to both the left and right side portions 24 in the front view, that is, the strain detecting means 26 is provided on any of the side portions 24. The strain detecting means 26 may be provided only on one side portion 24. In this case, in response to this change, the calculation unit 12 appropriately changes the calculation formula for calculating the load, such as adding the loads corresponding to the individual strain information to calculate the load.

Further, although the strain measuring unit 42, the control unit 43, and the computer 44 are separate individuals and are connected and unitized, they may be configured by one device having each function. Further, the strain measuring unit 42 and the control unit 43 may form one device, or the control unit 43 and the computer 44 may form one device.

Further, the detection unit 11, that is, the strain gauges 261,262 are connected to the strain measuring unit 42 to which the input connector 41 is connected by a wired method via the communication cable 30, but the strain measuring unit 42 is connected. Communication may be made wirelessly, and the strain gauges 261,262 may be made wireless so that the strain gauges 261,262 and the strain measuring unit 42 are connected by communication in a wireless manner. Further, the strain gauges 261,262 and the control unit 43 or the computer 44 may be wirelessly connected to each other.

Further, the load calculation program 471 and the determination program 472 are stored in the mobile terminal constituting the display unit 14 capable of displaying the load acting on the hanger 2 such as the display 45, and the mobile terminal is the calculation unit 12 and the determination unit. 13 may also be configured.

In this case, the control unit 43 and the mobile terminal may be allowed to wirelessly communicate with each other so that the mobile terminal can receive strain information from the control unit 43 and calculate the load acting on the hanger 2. Alternatively, the strain gauges 261,262 and the mobile terminal may be capable of wireless communication so that the mobile terminal can receive strain information from the detection unit 11 and calculate the load acting on the hanger 2. In this case, since the case 60 is not arranged on the upper surface of the bridge girder 9, the work space can be widened and the work safety can be improved.

Further, the warning unit 15 is not configured by the warning light 46, and when the determination unit 13 determines that the load acting on the hanger 2 exceeds the threshold value, a warning is displayed on the display 45 to display the warning unit 15. It may be configured by 45.

Further, the safety management system 10 may not be provided with the determination unit 13 and the warning unit 15.

Further, in the first embodiment, the strain generated in the side portion 24 is detected by the strain gauges 261,262, but for example, the strain may be detected by a sensor having another configuration.

Further, in the first embodiment, the individual strain information detected by the strain gauges 261 and 262 is individually sent to the strain measuring unit 42, but the four strain gauges 261 and the four strain gauges 261 attached to the hanger 2 are attached. The tip of the lead wire of 262 may be connected to an adder circuit or the like and added up to be sent as strain information to the tip.

Further, in the first embodiment, the strain measuring unit 42 converts the individual strain information for 4 channels into a digital signal every 500 msec and transmits it to the control unit 43, and further, the CPU 48 is sent to each hanger 2 every 500 msec. The acting load is calculated and displayed on the display 45, and this time interval can be appropriately set.

The program for realizing the functions of both or one of the calculation unit 12 and the determination unit 13 is not stored in the ROM 47, but is recorded on a recording medium readable by the computer 44 and recorded on the recording medium. The program may be loaded into the computer 44 and executed to perform the processing of the calculation unit 12 and the determination unit 13. The recording medium that can be read by the computer 44 is a portable medium such as a flash memory or a CD-ROM. Further, the program for realizing the functions of both or one of the calculation unit 12 and the determination unit 13 may be downloaded via a network such as the Internet or a communication line such as a telephone line.

Further, the above-described embodiment is merely an example, and does not limit the present invention in any way, and it goes without saying that various improvements and modifications can be made without departing from the gist thereof.

1 ... Strain detection hanger 2 ... Measuring hanger 3 ... Relay hanger 4 ... Chain block 5 ... Wire rope 6 ... Cable 7 ... Lifting jig 8 ... Mobile crane 9 ... Bridge girder block (load)
10 ... Safety management system 11 ... Detection unit 12 ... Calculation unit 13 ... Judgment unit 14 ... Display unit 15 ... Warning unit 20 ... Hanger body 21 ... Bolt 22 ... Nut 23 ... Central part 24 ... Side part 25 ... Insert hole 26 ... Strain detection means 27 ... Recess 30 ... Communication cable 40 ... Safety management device 41 ... Input connector 42 ... Strain measurement unit 43 ... Control unit 44 ... Computer 45 ... Display 46 ... Warning light 47 ... ROM
48 ... CPU
49 ... RAM
50 ... Wireless LAN slave unit 60 ... Case 261 ... Strain gauge 262 ... Strain gauge 471 ... Load calculation program 472 ... Judgment program

Claims (3)

It is a safety management system in the loading and unloading work that calculates the load acting on each hanger intervening between each of the plurality of cables and the load when the load is suspended by using a plurality of cables by a crane.
The hanger has a pair of side portions that are substantially U-shaped in front view and are parallel to each other at a distance from each other.
A detection means that is arranged on at least one of the pair of side portions and detects strain along the axis of both surfaces facing each other across the axis of the side portion.
A calculation means for calculating the load acting on the hanger for each hanger based on the strain information detected by the detection means is provided .
A safety management system in a loading and unloading operation , wherein both surfaces are surfaces in a direction orthogonal to the direction in which the pair of side portions are lined up . The safety management system for the loading and unloading work according to claim 1.
A safety management system for loading and unloading operations, wherein both surfaces, which are detection points of the detection means, are the front surface and the rear surface of the side portion. The safety management system for the loading and unloading work according to claim 1 or 2.
The detection means is a safety management system in a loading and unloading operation, characterized in that it is arranged on any of the pair of side portions.

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