JP2017178531A - Alarm device for rollover prevention - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alarm device for rollover prevention which eliminates the need for a control unit using an arithmetic circuit or the like, has an extremely simple structure, hardly causes human error, can generate an alarm reliably for rollover prevention, and can be used for a mobile crane.SOLUTION: An alarm device for rollover prevention inserted between an outrigger 100 of a mobile crane and a ground surface comprises: a lid part 2 in contact with an undersurface of the outrigger 100; a coil spring 3 supporting the lid part 2; an alarm container 1 storing the coil spring 3; a limit switch 31 fixedly attached in the alarm container 1; and an alarm buzzer 11 connected to the limit switch 31. The limit switch 31 is installed so as to be in an electrically conductive state when the displacement amount of the coil spring 3 becomes equal to or less than the displacement amount which is 500 kg or less as compared with an unload state.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a rollover prevention alarm device for warning a rollover in a mobile crane, and can be suitably used particularly for a load-type truck crane.

  Mobile cranes having cranes for loading and unloading vehicles are widely used in construction / construction sites and civil engineering sites. When loading and unloading work with a mobile crane, it is necessary to prevent the vehicle from falling over due to a suspended load. For this reason, when loading and unloading heavy loads, outriggers are projected from both sides of the vehicle and grounded, and work is performed while maintaining stability. However, there is a danger that the vehicle will roll over if the offset exceeds the limit due to overloading of the suspended load, causing injury to the worker. For this reason, it is obliged to attach an “overload limiting device” to a mobile crane having a suspension load of 3 tons or more.

  However, in this standard, it is necessary to detect the load of the load lifted by the crane, stop the crane and issue an alarm if this load exceeds the rated load. For this reason, the load load, boom length, hanging angle and work area must be taken into consideration, resulting in a complicated structure and high price. For this reason, small mobile cranes with a suspension load of less than 3 tons that are not obligated to install an “overload limiting device” are almost not equipped with alarm devices, and the work safety of the crane is the length and angle of the boom. In addition, it has been required to work by confirming the “work area diagram” representing the correlation between the suspension load and the suspension load. Such work is extremely complicated, and there is a concern that human errors may occur. For this reason, in an actual site, it is normal to work with the operator's eye measurements.

  On the other hand, as a technology to prevent the rollover accident of a mobile crane, there is also an alarm device configured to issue an alarm when the load on the outrigger on one side falls below a certain load instead of warning the crane overloading It has been proposed (Patent Document 1 and Patent Document 2). However, even these alarm devices require a control unit that uses an arithmetic circuit or the like that issues a warning by sensing a load signal from a load cell attached to the outrigger, which is also complicated in structure and expensive. .

JP 2003-171987 JP 2011-37565 A

  The present invention has been made in view of the above-described conventional situation, and in a mobile crane having an outrigger, a control unit using an arithmetic circuit or the like is unnecessary, the structure is extremely simple, and a human error occurs. An object of the present invention is to provide a rollover prevention alarm device that is difficult to generate and can reliably generate a rollover prevention alarm.

The rollover prevention alarm device of the present invention is a rollover prevention alarm device inserted between the outrigger of the mobile crane and the ground,
A top plate in contact with the lower surface of the outrigger, an elastic member for supporting the top plate, an alarm container for storing the elastic member, an electric switch fixedly mounted in the alarm container, and connected to the electric switch An alarm device, and
The electrical switch is installed so as to be in an electrically conductive state when the amount of displacement of the elastic member is equal to or less than a predetermined amount of displacement as compared with the unloaded state.

  That is, in the rollover prevention alarm device of the present invention, it is used by being inserted between the outrigger of the mobile crane and the ground, a top plate in contact with the lower surface of the outrigger, an elastic member that supports the top plate, An alarm container for storing the elastic member, an electric switch fixedly attached in the alarm container, and an alarm device connected to the electric switch are provided. The electrical switch is installed so as to be in an electrically conductive state when the amount of displacement of the elastic member becomes equal to or less than a predetermined amount of displacement compared to the unloaded state. For this reason, if the predetermined displacement amount of the elastic member is set slightly before the displacement amount causing the risk of the mobile crane overturning, the electrical switch is brought into an electrically conductive state before the mobile crane rolls over. Since the electric switch is connected to the alarm device, the alarm device is automatically activated, and an alarm is issued to notify the danger of rollover.

  As described above, the alarm device of the present invention does not require the use of a control unit using an arithmetic circuit or the like and has a very simple mechanical structure, so that the manufacturing cost is low. Even if the operator who performs the crane operation while checking the “work area diagram” is wrong, a warning for preventing rollover is surely issued, so that a human error is unlikely to occur.

The electrical switch is a reed switch, and has a magnet installation part provided with a magnet whose position moves in conjunction with the movement of the top plate. The reed switch is turned on and off according to the strength of the magnetic force received from the magnet. It can be.
Since the reed switch operates without contact with the magnet, the risk of mechanical failure can be reduced.

  Further, in the case where the electrical switch is a reed switch, the magnet installation portion is supported such that a magnet cage having one end in contact with the back side of the top plate and a magnet attached to the other end is swingable in the alarm container. You can also If this is the case, when this alarm device is placed on the ground and the outrigger is placed on it, the top plate is lowered and the magnet rod in contact with the back side of the top plate is swung to move the magnet upward. Then, after the reed switch is once turned on and an alarm is issued, the magnet is further raised, the reed switch is turned off, the alarm is stopped, and the rollover is monitored. For this reason, only by installing an alarm device between the ground and the outrigger, the operator can set the rollover monitoring state while checking the alarm operation without turning on the alarm device.

  Furthermore, a plurality of reed switches can be provided in parallel at different positions. If this is the case, an alarm will be issued if at least one of the plurality of reed switches is in the ON state. Therefore, the area where the alarm is driven by appropriately selecting the positions of the plurality of reed switches. Can be freely selected.

  The electric switch is a limit switch, and a stopper is installed in the alarm container to prevent the top plate from being lowered due to the displacement of the elastic member. The tip of the head of the limit switch has the same height as the upper end of the stopper. It can also be installed so that it is in an OFF state.

  In this case, if the position of the upper end of the stopper is set to a position where the displacement movable amount of the elastic member is slightly larger than the displacement amount that causes the danger of the mobile crane overturning, before the mobile crane rolls over The electrical switch is brought into an electrical continuity state. Since the electric switch is connected to the alarm device, the alarm device is automatically activated, and an alarm is issued to notify the danger of rollover.

It is sectional drawing of the alarm device for rollover prevention of Example 1. FIG. It is a top view when the top plate of the alarm device for rollover prevention of Example 1 is opened. It is sectional drawing which shows the installation process of the alarm device for rollover prevention of Example 1. FIG. It is principal part sectional drawing which shows the operation principle in the installation process and drive state of the alarm device for rollover prevention of Example 1. FIG. It is principal part sectional drawing of the alarm device for rollover prevention of Example 2. FIG. It is an electric circuit diagram of the alarm device for rollover prevention of Example 2. It is sectional drawing of the alarm device for rollover prevention of Example 3. FIG. It is a top view when the top plate of the alarm device for rollover prevention of Example 3 is opened. It is sectional drawing which shows the installation process of the alarm device for rollover prevention of Example 3. FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.
Example 1
FIG. 1 shows an alarm device for preventing rollover according to the first embodiment. This alarm device includes a square container-shaped alarm container 1 having a side of 200 mm and an inner dimension of 45 mm, and a lid 2 that is extrapolated to the alarm container 1. The lid part 2 is a top plate. As shown in Fig. 2, the alarm container 1 is made up of 17mmφ steel round bars and 45mm stoppers 3 which are the same height as the inner dimensions of the alarm container 1 are installed vertically by welding. Has been. Each stopper 3 is inserted with a coil spring 4 having an outer diameter of 40 mmφ, an inner diameter of 20 mmφ and a spring constant of 200 kg / cm.
As shown in FIGS. 1 and 2, a rectangular plate-like switch mounting board 5 is erected at the central portion of the alarm container 1, and a reed switch 6 is fixed to one end side of the switch mounting plate 5. Installed. A magnet rod 7 is rotatably supported on the switch mounting substrate 5 by a shaft 8, and a rotating roller 9 is rotatably mounted on one end side of the magnet rod 7. A permanent magnet 10 is fixedly attached to the side. The magnet rod 7 is configured such that the permanent magnet 10 side is lowered by the urging force of the coil spring 7 a, the rotating roller 9 side is raised, and comes into contact with the back side of the lid portion 2.
Further, as shown in FIG. 2, an alarm buzzer 11 containing a battery is installed inside the alarm container 1, and the alarm buzzer 11 is connected to the reed switch 6.

When using the rollover prevention alarm device of the first embodiment configured as described above, first, as shown in FIG. 3, the alarm device is placed at the place where the outrigger 100 of the mobile crane is installed (FIG. 3). (See (a) and FIG. 4 (a)). Then, the outrigger 100 is lowered and placed on the alarm device (FIG. 3B). At this time, the rotating roller 9 is pushed downward while the back side of the lid 2 is in contact with the rotating roller 9. As a result, the magnet rod 7 rotates about the shaft 8 as a fulcrum, and the permanent magnet 10 fixed to the magnet rod 7 moves upward to enter the sensing range where it overlaps the reed switch 6 (FIG. 4B). The reed switch 6 is turned on and the alarm buzzer 11 sounds. Then, the permanent magnet 8 moves further upward, and the reed switch 6 is turned off when the reed switch 6 is again out of the sensing range where it does not overlap with the permanent magnet 8, and the sound of the alarm buzzer 11 stops. The repulsive force of the coil spring 4 at this time is set to 500 kg. Further, the pressure from the outrigger 100 increases, the back side of the lid portion 2 comes into contact with the stopper 3, and the outrigger 100 stops (the state shown in FIGS. 3B and 4C).
Therefore, the worker simply puts the alarm device at the installation location and places the outrigger 100 on the alarm device, so that the alarm buzzer 11 sounds temporarily and the alarm buzzer 11 stops again to confirm the operation of the alarm device. The preparation for installing the alarm device is completed.

  After the above installation preparation work is completed (that is, after the state shown in FIG. 4 (c)), the operator operates the crane. , The rotating moment proportional to the product of the weight of the suspended load and the boom length is generated, and the ground pressure of the outrigger on the opposite side of the suspended load is reduced. When the repulsive force of 4 or less is 500 kg or less, the lid 2 is raised, the magnet rod 7 rotates about the shaft 8, and the permanent magnet 10 fixed to the magnet rod 7 moves downward. The detection range that overlaps with the reed switch 6 is entered (FIG. 4B), whereby the alarm buzzer 11 sounds and the operator recognizes that the vehicle is in a rollover risk area.

(Example 2)
As shown in FIG. 5, the rollover prevention alarm device according to the second embodiment has reed switches installed at two positions (20a, 20b) at different positions. Both reed switches 20a and 20b are connected to form a parallel circuit as shown in FIG. Others are the same as those in the first embodiment, and the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  In the alarm device of the second embodiment, since the reed switch is installed in parallel at two positions (20a, 20b) at different positions, the alarm buzzer 11 sounds when any of the reed switches is turned on. . Therefore, as shown in FIG. 5, there is an advantage that the sensing range for notifying the dangerous area can be widened and the sensing range can be freely controlled by selecting the installation location. Other operations and effects are the same as those in the first embodiment, and a description thereof will be omitted.

(Example 3)
As shown in FIGS. 7 and 8, the alarm device for preventing rollover of the third embodiment has a limit switch 31 attached to the upper end of the switch mounting substrate 5, and the upper end of the head portion 31a is a stopper at the upper end of the head portion 31a. The neutral terminal and the normally closed terminal are connected to the electric circuit so that the OFF state is obtained when the height becomes the same as the upper end of 4. The limit switch 31 is connected to the alarm buzzer 11, and an open / close switch 32 and a battery 33 are attached to the alarm buzzer. Others are the same as in the first embodiment, and the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  When using the alarm device of Example 3, as shown in FIG. 9, first, the alarm device is placed at a place where the outrigger 100 of the mobile crane is installed (FIG. 9A). Then, the operation check is performed by turning ON / OFF the switch 32 of the alarm device and sounding the alarm buzzer 11. Then, after turning off the open / close switch 32 to stop the sound of the alarm buzzer 11, the outrigger 100 is lowered and placed on the alarm device (FIG. 9B). As a result, the lid 2 receives the ground pressure from the outrigger 100 and descends against the repulsive force of the coil spring 3, and comes into contact with the stopper 3 and stops. At this time, the head portion 31a of the limit switch 31 is pushed down by the back surface of the lid portion 2, and the limit switch 31 is turned off. Then, the opening / closing switch 32 is turned on again, and the preparation for installing the alarm device is completed.

  After the above installation preparation work is completed (that is, after the state shown in FIG. 9B), the operator operates the crane. , The rotating moment proportional to the product of the weight of the suspended load and the boom length is generated, and the ground pressure of the outrigger on the opposite side of the suspended load is reduced. When the repulsive force of 4 is 500 kg or less, the lid 2 is raised, the limit switch 31 is turned on, the alarm buzzer 11 sounds, and the operator recognizes that he is in a rollover risk area.

  The present invention is not limited to the description of the embodiments and examples of the invention described above. Various modifications are included in the present invention as long as those skilled in the art can easily conceive without departing from the scope of the claims.

100 ... Outrigger 2 ... Top plate (lid)
3. Elastic member (coil spring)
4. Stopper 2. Alarm container 6, 20a, 20b, 31 ... Electric switch (6, 20a, 20b ... Reed switch, 31 ... Limit switch)
31a ... Head 11 ... Alarm (alarm buzzer)
6,7,8,9 ... Magnet installation part (6 ... Permanent magnet, 7 ... Magnet cage, 8 ... Shaft, 9 ... Rotating roller material)
6 ... Magnet (permanent magnet)

Claims (5)

An alarm device for preventing rollover inserted between the outrigger of the mobile crane and the ground,
A top plate in contact with the lower surface of the outrigger, an elastic member for supporting the top plate, an alarm container for storing the elastic member, an electric switch fixedly mounted in the alarm container, and connected to the electric switch An alarm device, and
The electrical switch is installed so as to be in an electrically conductive state when the amount of displacement of the elastic member is equal to or less than a predetermined amount of displacement compared to the unloaded state. . The electrical switch is a reed switch;
A magnet installation portion provided with a magnet whose position moves in conjunction with the movement of the top plate;
The rollover prevention alarm device according to claim 1, wherein the reed switch is turned on and off according to the strength of the magnetic force received from the magnet.   The said magnet installation part is one side in contact with the back side of the said top plate, and the magnet cage | basket | attachment with which the said magnet was attached to the other end side is supported so that it can swing within the said alarm container. Alarm device.   4. The rollover prevention alarm device according to claim 2, wherein a plurality of the reed switches are provided at different positions in parallel connection. The electrical switch is a limit switch;
A stopper is provided in the alarm container to prevent the top plate from descending due to the displacement of the elastic member. When the tip of the limit switch head is flush with the upper end of the stopper, the alarm container is turned off. The overturning-preventing alarm device according to claim 1, installed as described above.

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