JP4817739B2 - Boom overload prevention device for concrete pump car with boom - Google Patents

Description

  The present invention provides a boom for a concrete pump vehicle with a boom for preventing the possibility of an excessive tip load acting on the boom from a concrete discharge hose suspended from the tip of the boom of the concrete pump vehicle with a boom. The present invention relates to an overload prevention device.

  Among concrete pump cars, for example, in concrete placement work at high places accompanying the construction of high-rise buildings, a wide range of concrete placement work, placement work at locations away from the stop position of the concrete pump car, etc. As shown in FIGS. 3 (a) and 3 (b), a boom-equipped concrete pump truck is widely used.

  That is, the concrete pump vehicle shown in FIGS. 3 (a) and 3 (b) is configured to suck and discharge the hopper 2 and the concrete in the hopper 2 onto the deck 1 at the rear of the vehicle body. Not shown). A swing frame 3 is mounted on the deck 1 so as to be swingable by a hydraulic actuator (not shown). Further, a lower boom 5 is mounted on the upper side of the revolving frame 3 so that the lower end of the revolving frame 3 can be raised and lowered, and a lower end boom 5 is connected to the upper end of the lower boom 5 so as to be raised and lowered. Then, a middle boom 6 that can be raised and lowered with respect to the lower boom 5, and an upper boom 7 that can be raised and lowered with respect to the middle boom 6 by connecting the proximal end side to the distal end of the middle boom 6 so as to be raised and lowered. A boom 4 of a multi-stage type (three-stage type in the figure) constructed from the above is installed.

  Further, after the concrete pipe 8 for transporting the concrete sucked and discharged from the hopper 2 by the concrete pump is placed along the deck 1 from the concrete pump, the booms 5 of the respective stages of the multistage boom 4 are provided. 6 and 7 are supported. As shown in FIG. 3B, a flexible hose 9 is connected to the tip of the concrete pipe 8 as a concrete discharge hose, and the base hose 9 is connected to the boom 4. As shown in FIG. 3 (a), a hose for discharging concrete is provided at the tip of the root hose 9, as shown in FIG. The leading end hose 11 is connected, and the leading end discharge port 11a of the leading end hose is made to face the concrete placing place (see, for example, Patent Document 1).

  By the way, in the concrete pump vehicle with a boom as described above, among the root hose 9 and the tip hose 11 as the concrete discharge hose, the load of the root hose 9 and the tip hose 11 of the portion hanging from the boom 4; Since the structure is such that the load of concrete (not shown) existing inside the hose during the process of being pumped through the hoses 9 and 11 acts on the tip of the boom 4, When an excessive tip load, that is, an overload is applied to the boom 4 due to the connection of the extension hose, there is a concern that the boom 4 may be damaged or broken. Therefore, in the concrete pump vehicle with the boom, the limit of the tip load of the boom 4 is notified to the user by, for example, a name plate (not shown) or an instruction manual attached to a required part of the vehicle body. .

  In recent years, it is obliged to take measures to prevent the tip hose 11 from dropping off in a boom-equipped concrete pump truck.

JP 11-172919 A

  However, in the conventional concrete pump vehicle with a boom, no means for detecting the tip load acting on the boom 4 is provided in particular, and therefore, as described above, the limit of the tip load of the boom 4 is limited. Is shown on the nameplate and instruction manual, the concrete discharge hose 9 hung down from the boom 4 when carrying out the concrete placing work using the boom-equipped concrete pump car at the construction site, 11, the fact that the end load actually acting on the boom 4 is within the allowable range shown in the nameplate and the instruction manual cannot be judged objectively by the user. It is.

  As a method for enabling detection of the tip load acting on the boom 4, it is conceivable to install a sensor for measuring the load at the tip of the boom 4. In this case, In order to prevent the electric wiring for signal transmission from being twisted even when the boom 4 is fully turned by the turning operation of the turning frame 3, it is necessary to newly develop and equip a slip ring and a wireless device. The problem of increasing the volume arises.

  Therefore, the present invention provides that the tip load acting on the boom from the concrete discharge hose suspended from the tip side of the boom in the concrete pump vehicle with the boom is within an allowable range due to the structure of the boom. The boom overload prevention device for a concrete pump vehicle with a boom that can be easily recognized as to whether or not it is over, can prevent the possibility of overload acting on the boom, and can be realized at a low cost as a simple structure. Is to provide.

In order to solve the above-mentioned problem, the present invention, as corresponding to the invention according to claim 1, is to support the concrete pipe on a multistage boom provided on the swivel frame so that it can be raised and lowered. In a concrete pump vehicle with a boom, the concrete discharge hose connected to the distal end side is suspended from the distal end side of the boom, and the upper end of the concrete discharge hose suspended from the distal end side of the boom A scale-like load indicator with a display unit that displays the magnitude of the load of the concrete discharge hose is interposed between the hose for hanging the hose and the supporting member attached so as to support the load of the hanging portion of the hose at a close position. by, as through該荷heavy indicator suspending the support member to the distal end side of the boom, and the distal end side of the boom the load indicator Attached to the serial supporting member, the load of the depending portion of the concrete discharge hose, so as to support the tip side of the boom through the support member and the load indicator, the load of the depending portion of the hose It shall be the composition which can be displayed on the display part of a load indicator.

Further, the scale-shaped load indicator in the above configuration is connected to the upper end side and the lower end side connecting members arranged in the vertical direction with a spring member interposed therebetween, and the upper end side connecting member is connected to the tip end side of the boom. The spring member can be expanded and contracted according to the load acting on the lower end side connection member in a supported state, and the magnitude of the load can be displayed on the display unit based on the magnitude of the deformation amount of the spring member. The configuration is a spring balance type load indicator.

Furthermore, the scale-like load indicator in the upper Ki構 formed, provided with a display window, a display member fixed, a slide member that can slide in telescopic deformation of the spring member, the outer surface and the sliding member of the display member outer surface And a display unit that can display the magnitude of the load of the hanging portion of the concrete discharge hose by changing the display color.

  A support member that can support the load of the hanging portion of the concrete discharge hose in each of the above-described structures is attached and held at a position that is a predetermined distance away from the support member in the hanging portion of the concrete discharge hose. The holding member to be made is connected by a cord-like object having a dimension slightly longer than the hose length between the support member and the holding member.

According to the boom overload prevention device for a concrete pump vehicle with a boom according to the present invention, the concrete pipe is supported on the multistage boom provided on the swivel frame so as to be raised and lowered, and is connected to the front end side of the concrete pipe. In a concrete pump truck with a boom that is adapted to suspend a discharge hose from the tip end side of the boom, the hose is positioned at a position near the top end of the concrete discharge hose suspended from the tip end side of the boom. between the support member mounted so as to support the load of the depending portion of, with intervening scale-like load display equipped with a display unit for displaying the magnitude of the load of the concrete discharge hose, 該荷heavy display The load indicator is connected to the front end side of the boom and the support so that the support member is suspended from the front end side of the boom via a device. Attached to the member, the load of the depending portion of the concrete discharge hose, the support member and through a load indicator so as to support the tip side of the boom,該荷heavy display the load hanging portion of the hose A configuration that can be displayed on the display unit of the vessel, specifically, by connecting the scale-like load indicator to the upper end side and the lower end side connecting member arranged in the vertical direction with a spring member interposed therebetween. The spring member is caused to expand and contract in response to a load acting on the lower end side connection member in a state where the upper end side connection member is supported on the tip end side of the boom, and based on the magnitude of the deformation amount of the spring member. Thus, the load balance type load indicator that can display the magnitude of the load on the display unit is used, and the following excellent effects are exhibited.

(1) Based on the display on the display unit of the load indicator, it is possible to easily recognize whether or not there is a possibility that an excessive tip load exceeding the structurally allowable value may act on the boom. For this reason, the possibility that an overload may act on the boom can be prevented in advance, and the possibility of breakage or breakage of the boom can be solved.
(2) Since the load indicator is made of a spring scale, electrical equipment can be dispensed with, so there is no need for electrical wiring for signal transmission, and there is no problem even during the entire turning of the boom due to the turning motion of the turning frame. There is no. Therefore, since it is not necessary to newly develop a slip ring or a wireless device, it can be manufactured at low cost. Moreover, since it has a simple structure, it can be easily applied to various types of concrete pump trucks with booms, and can be easily attached to existing concrete pump cars with booms.
(3) A scale-shaped load indicator is provided with a display window, a fixed display member, and a slide member that can be slid by expansion and contraction of a spring member, and can recognize the outer surface of the display member and the outer surface of the slide member. By using a different color and having a display unit that can display the magnitude of the load of the hanging part of the concrete discharge hose by changing the display color, the user can use the concrete discharge hose. Therefore, the magnitude of the load acting on the boom can be easily recognized based on the change in color displayed on the display unit.
(4) A support member that can support the load of the hanging portion of the concrete discharge hose is attached and held at a position that is a required distance away from the support member in the hanging portion of the concrete discharge hose. By making the holding member to be connected with a cord-like object having a dimension slightly longer than the hose length between the supporting member and the holding member, it is possible to prevent falling when the hose is broken, and it is obligatory. Therefore, the structure can be made simpler than the case of separately providing a concrete discharge hose fall prevention device.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIGS. 1 and 2 (a), (b), (c), and (d) show an embodiment of the boom overload prevention device for a boom-equipped concrete pump vehicle according to the present invention. In a concrete pump vehicle with a boom similar to that shown in FIG. 2), the load of the hose hanging portion (the inside of the hose) near the top end of the boom 4 and the upper end of the concrete discharge hose suspended from the tip of the boom 4 It is attached so that a scale-like load indicator 13 is interposed between the support member 12 so as to support the load (including the load of concrete) and the load of the hanging portion of the concrete discharge hose is applied to the support member 12. And the load indicator 13 to be supported on the tip end side of the boom 4, so that the boom 4 can be removed from the concrete discharge hose hanging from the boom 4. The tip load acting on the end side, to be displayed on the load display device 13.

  More specifically, the concrete discharge hose is connected to the distal end side of the concrete pipe 8 supported on the boom 4 and attached to the distal end portion of the boom 4 as shown in FIG. A root hose 9 that is guided and hung down, a connecting pipe 14 having a base end attached to the distal end of the root hose 9 as a taper shape with a required diameter reduced toward the lower end side that is the distal end side, and the connecting pipe 14 The tip hose 11 is slightly smaller in diameter than the root hose 9 connected to the tip end portion.

  In addition, brackets 15 are provided at required positions on both the left and right sides of the hose guide 10, and the upper end side connection members 17 of the scale-shaped load indicators 13 are connected to the brackets 15 via turnbuckles 16, respectively. To do. Further, the support member 12 for supporting the load of the root hose 9, the connection pipe 14, and the tip hose 11 hanging from the tip end of the boom 4 corresponds to the outer diameter of the intermediate portion in the longitudinal direction of the connection pipe 14. A ring-shaped cloth band having a diameter, and the support member 12 is fitted to the connecting pipe 14 having a tapered shape that is reduced in diameter toward the lower end side, and is attached to the outer periphery of the intermediate portion in the longitudinal direction of the connecting pipe 14. Furthermore, a suspension member 18 made of a cord-like material attached to a required portion in the circumferential direction of the support member 12 is connected to the lower end side connection member 19 of the load indicator 13 so as to be suspended. Thus, with the turnbuckle 16 loosened, the turnbuckle 16, the load indicator 13, and the suspension member 18 attached to the support member 12 are suspended in order from the bracket 15 of the hose guide 10 as described above. After the connection, the turnbuckle 16 is tightened, and the loads of the root hose 9, the connecting pipe 14 and the tip hose 11 hanging from the tip side of the boom 4 are suspended from the support member 12 to the suspension member 18. By receiving and supporting the bracket 15 of the hose guide 10 via the load indicator 13 and the turnbuckle 16, the root hose 9, the connecting pipe 14, and the distal end hanging from the distal end side of the boom 4 are supported. The load of the hose 11 can be detected and displayed by the scale-like load indicator 13.

  Further, a connection portion 20 such as a hook is provided at a required position in the circumferential direction (two locations in the figure) of the support member 12 attached to the outer periphery of the connection pipe 14. A holding member 21 such as a cloth band attached to the outer periphery of a required portion of the intermediate portion that is a required distance away from the support member 12 toward the tip side is a hose length between the holding member 21 and the support member 12 ( It is configured to be connected via a cord 22 such as a wire that is slightly longer than the separation distance. As a result, even if the upper portion of the root hose 9 or the tip hose 11 is broken due to deterioration of the root hose 9 or the tip hose 11, the holding members are used to hold the hoses 9, 11 closer to the tip than the broken portion. 21, the rope 22, the support member 12, the suspension member 18, the load indicator 13, and the turnbuckle 16 so that the hose guide 10 at the tip of the boom 4 can support the hose. Even when the wires 9 and 11 are broken, the hoses 9 and 11 are held so that they can be prevented from falling.

  As shown in FIGS. 2 (a), (b), (c), and (d), the load indicator 13 has upper and lower connecting members 17 and 19 arranged in the vertical direction having a required spring constant. The spring member 23 is connected via a spring member 23 so that the spring member 23 expands and contracts in response to a load acting on the lower end side connection member 19 in a state where the upper end side connection member 17 is supported on the fixed side. A so-called spring balance type equipped with a display unit 24 for displaying the magnitude of the load acting on the lower end side connecting member 19 based on the amount of deformation of the spring member 23 so that it can be easily recognized from the outside. The configuration is as follows.

  More specifically, the load indicator 13 includes a cylindrical casing 25 extending in the vertical direction with a required dimension, and is connected so as to penetrate the central portion of the lid portion 26 that closes the upper end portion of the casing 25 in the vertical direction. The member 27 is attached, and the lower end portion of the upper end side connecting member 17 having a shape having a hook on the upper portion is connected to the connecting member 27. The spring member 23 is set so that the total length when contracted is about half of the axial direction dimension of the casing 25, and the spring member 23 is placed inside the casing 25 along the axial center of the casing 25. While accommodating so that it can expand-contract, the upper end part of this spring member 23 is connected with the connection member 27 of the center part of the said cover part 26. As shown in FIG. Further, the lower end portion of the casing 25 is closed with a bottom portion 28 having an opening portion 29 having a required diameter at the center portion, and is shaped like a rod slightly longer than half of the axial direction dimension of the casing 25, and at the lower end portion. The upper end side of the lower end side connection member 19 having a hook shape is slidably inserted into the opening 29 of the bottom portion 28, and the lower end portion of the spring member 23 is connected to the lower end side connection member 19. To do.

  The display unit 24 of the load indicator 13 has a display window 30 opened on the peripheral wall at one side position in the upper half of the casing 25 so as to extend along the axial direction of the casing 25 with a required width, From a transparent cover (not shown) that is curved along the peripheral wall of the casing 25 that is attached to the display window 30 as necessary, and the spring member 23 that is housed in the casing 25 inside the display window 30. Also, the casing 25 is arranged at a position on the outer peripheral side so as to face the display window 30 with a necessary gap therebetween, and has a casing 25 axial direction dimension and width dimension substantially the same as the display window 30 and a peripheral wall of the casing 25. The display member 31 has a cylindrical wall shape that is concentrically curved, and a slide member 32 that slides so as to be accommodated between the display window 30 and the display member 31. The upper end of the timber 31, attached to the inner surface (lower surface) of the lid portion 26 of the casing 25. Further, the cylindrical slide member 32 having an outer diameter slightly smaller than the inner diameter of the casing 25 and having a peripheral wall thinner than the gap between the display window 30 and the display member 31 is substantially the same as the casing 25. It is formed so as to have a dimension in the axial direction of about half, and is arranged in the casing 25 so as to be slidable in the axial direction along the inner surface of the peripheral wall of the casing 25. The direction required portion is attached to the connecting portion between the lower end portion of the spring member 23 and the lower end side connection member 19 via a radial attachment member 33. Furthermore, the outer surface of the display member 31 and the outer peripheral surface of the slide member 32 can be easily identified in color, for example, the outer surface of the display member 31 is red, and the outer peripheral surface of the slide member 32 is green. They are painted separately.

  Therefore, according to the load indicator 13 having the above configuration, when the load is not applied and the spring member 23 is in the contracted state as shown in FIGS. Since it is accommodated in the gap between the display member 31 and the display window 30, only the outer peripheral surface of the slide member 32 is exposed to the outside through the display window 30. Therefore, from the outside, a state where the entire surface of the display window 30 is displayed in green is observed. On the other hand, when a load is applied to the lower end side connecting member 19 and the spring member 23 is extended according to the magnitude of the load as shown in FIGS. The position of the slide member 32 is lowered downward in accordance with the downward displacement. For this reason, the display member 31 which was initially covered on the entire outer peripheral side by the slide member 32 is gradually exposed to the outside through the display window 30 from the upper end side. Accordingly, when viewing the display window 30 from the outside, when a load is applied to the lower end side connecting member 19, the inside of the display window 30, which was initially green, gradually turns red from the upper end side. The situation begins to be observed. At this time, there is a correlation between the magnitude of the load acting on the lower end side connecting member 19 and the amount of deformation of the spring member 23, and the display window 30 changes color from green to red. Since the lower end position of the discoloration region is determined by the position of the upper end edge of the slide member 32 that is displaced (slids) downward as the spring member 23 extends, the load size and the display window 30 are determined. The displacement in the vertical direction at the lower end position level of the color changing region that changes color from green to red has a correlation. Therefore, as described above, the left and right sides provided between the brackets 15 provided on the left and right side positions of the hose guide 10 on the distal end side of the boom 4 shown in FIG. 1 and the support member 12 attached to the connecting pipe 14 are provided. When the load of the root hose 9, the connecting pipe 14 and the tip hose 11 suspended from the tip side of the boom 4 is detected by the load indicator 13, the load reaches the upper limit of the allowable range of the tip load of the boom 4. When reaching, the lower end position of the color changing region from green to red in the display window 30 in the left and right load indicators 13 is lowered to, for example, the position of the mark 34 attached to the middle portion in the vertical direction of the display window 30. In addition, the spring constant of the spring member 23 is set. As a result, the user of the boom-equipped concrete pump vehicle visually observes the display window 30 of the load indicator 13, and the lower end position of the color change region from green to red in the display window 30 is lowered to the position of the mark 34. It is possible to determine whether or not the tip load acting on the boom 4 is within an allowable range only by observing whether or not it is.

  Actually, when the concrete discharge operation is performed by the operation of the concrete pump, the root hose 9 and the tip hose 11 which are concrete discharge hoses pulsate, so that a dynamic load is applied to the load indicator 13. For this reason, the display in the display window 30 of the load indicator 13 is constantly fluctuating, and the magnitude of the tip load of the boom 4 can be determined from the display in the display window 30. It will be difficult. In this case, a tip that acts as a static load on the boom 4 in advance from a concrete discharge hose comprising a root hose 9, a connecting pipe 14, and a tip hose 11 that hangs down from the tip of the boom 4 before the operation of the concrete pump. The correlation between the load and the tip load that acts as a dynamic load on the boom 4 during operation of the concrete pump is obtained, and the tip load that acts as a dynamic load on the boom 4 during operation of the concrete pump is The allowable range of the tip load as the static load before the concrete pump operation is calculated and obtained so as to be within the allowable range of the tip load defined by the structure of the boom 4. The upper limit of the allowable range of the tip load and the static load of the root hose 9, the connecting pipe 14, and the tip hose 11 in the portion depending from the boom 4 Spring constant of the spring member 23 so that the lower end of the color changing region from green to red is positioned at the position of the mark 34 provided in the middle portion of the display window 30 of the load indicator 13 in the vertical direction. Should be set in advance.

  In addition, the same components as those shown in FIGS. 3A and 3B are denoted by the same reference numerals.

  With the above configuration, before the concrete pump is operated, that is, the root hose 9, the connecting pipe 14, and the tip hose 11, which are concrete discharge hoses, are suspended from the tip side of the boom 4, and the tip 11 a ( 3 (see FIG. 3 (a)), the user looks at the display window 30 of the load detector 13 at the stage where it faces the placement site, and the lower end of the color change range from green to red in the display window 30. However, if it is located above the mark 34 attached to the display window 30, there is no possibility that an excessive tip load (overload) acts on the boom 4, so that the placing operation is performed as it is. do it. On the other hand, when the lower end of the color change area from green to red in the display window 30 is below the position of the mark 34 attached to the display window 30, there is a possibility that an overload acts on the boom 4. Therefore, before starting the placing operation, the length of the tip hose 11 is reviewed so that the lower end of the color change area from green to red in the display window 30 is positioned above the mark 34. After that, start the placement work.

  Thus, according to the boom overload prevention device for a concrete pump vehicle with a boom of the present invention, an excessively large tip that is structurally acceptable for the boom 4 is obtained only by visually observing the display window 30 of the load indicator 13. Since it is possible to easily recognize whether or not there is a possibility that a load acts, it is possible to prevent the possibility that an overload will act on the boom 4. Therefore, the possibility of breakage or breakage of the boom 4 can be eliminated.

  Further, the load indicator 13 is in the form of a spring scale, does not use electrical equipment, and does not require electrical wiring for signal transmission. There is no hindrance, and it is not necessary to newly develop a slip ring or a wireless device, so that it can be manufactured at low cost. Moreover, since it has a simple structure, it can be easily applied to various types of boom-equipped concrete pump cars, and can be easily mounted on existing concrete pump cars.

  Further, since the tip hose 11 can be prevented from falling, the required concrete discharge hose fall prevention device can be integrated, and the concrete discharge hose fall prevention device is separately provided. The structure can be made simpler than the case of providing.

  Furthermore, since the base hose 9, the connection pipe 14, and the support member 12 for supporting the load of the front end hose 11 depending from the distal end side of the boom 4 are attached to the connection pipe 14, the connection pipe 14 Since the front end hose 11 connected to the front end side can be easily attached and detached, the replacement work of the front end hose 11 can be facilitated.

  In addition, this invention is not limited only to the said embodiment, The concrete discharge hose is good also as a form which connected the front-end hose 11 directly to the front-end | tip of the root hose 9, and the support member 12 is If the concrete discharge hose is attached at a position near the upper end of the concrete discharge hose so as to support the load of the concrete discharge hose hanging from the tip end side of the boom 4, it may be attached at a position other than the connecting pipe 14. Further, any structure other than a cloth belt may be used.

  A holding member 21 mounted on the outer periphery of the intermediate portion of the tip hose 11 is connected to the support member 12 mounted on the outer periphery of the connecting pipe 14 via a cord-like object 22, and a concrete discharge hose is connected. However, the upper end side of the cord-like object 22 is connected to a required support member attached to the root hose 9, the connecting pipe 14, or the upper end of the tip hose 11. Thus, separately from the function of detecting the overload of the boom 4, a concrete discharge hose fall prevention device may be provided separately.

  Although the upper end side connection member 17 of the load indicator 13 is shown as being connected to the bracket 15 of the hose guide 10 via the turnbuckle 16, if it can be supported by the tip of the boom 4, for example, Any support structure may be used, such as support by a bracket installed directly at the tip. Further, the turnbuckle 16 may be interposed between the lower end side connection member 19 of the load indicator 13 and the suspension member 18 attached to the support member 12, and further, for example, the tip of the connection pipe 14 In a state where a large load is not applied to the support member 12 attached to the connecting pipe 14 such as when the front end hose 11 is removed, the load indicator is lifted while slightly raising the position of the support member 12. 13 is connected to the bracket 15 of the hose guide 10, and the lower end side connection member 19 is connected to the suspension member 18 attached to the support member 12, and then the support member 12 is released. The load of the concrete discharge hose that hangs from the tip end side of the boom 4 acting on the support member 12 is transmitted to the bracket of the hose guide 10 via the load indicator 13. If it is possible to cause supported by 15, it may be omitted turnbuckle 16.

  The load indicator 13 includes a spring member 23 between the upper end side connecting member 17 and the lower end side connecting member 19, the amount of deformation of which changes according to the magnitude of the load acting when a load is applied. If the spring balance-like configuration is provided with a display unit 24 that can display the magnitude of the tip load acting on the boom 4 based on the amount of deformation, the compression spring type spring is replaced with the tension spring type spring member 23 shown in the figure. A spring member may be used. Further, the expansion / contraction deformation of the spring is converted into a change in the rotation angle of the required display member via a rack, a pinion, etc., and the load acting from the rotation angle of the display member is converted. Any type conventionally used for a spring balance may be adopted, such as a type that can recognize the size. Further, the connecting members 17 and 19 on the upper end side and the lower end side may have any shape such as an eye shape as long as they can be connected to the respective connection objects.

  In the above-described embodiment, the exposure amount of the red display member 31 and the green slide member 32 in the display window 30 according to the magnitude of the load of the concrete discharge hose suspended from the boom 4 in the load indicator 13. In the display window 30, the magnitude of the load can be determined based on the change in the lower end position level of the color change region from green to red in the display window 30. The 32 colors may be arbitrarily set as long as they can be easily identified. In order to easily determine the magnitude of the load acting on the load indicator 13, it is preferable to display the magnitude of the load by the color change in the display window 30, but the load indicator 13 In the same way as a normal spring balance, the position of the pointer changes according to the magnitude of the load, and to what extent the position of the pointer is displaced, the end load of the boom 4 reaches the upper limit of the allowable range It is good also as a type which comprises the mark for showing. In addition, it goes without saying that various modifications can be made without departing from the scope of the present invention.

It is a schematic side view which shows one Embodiment of the boom overload prevention apparatus of the concrete pump truck with a boom of this invention. 1 is an enlarged view of a load indicator portion in the apparatus of FIG. 1, (A) is a partially cut front view showing a state in which a spring member is contracted, and (B) is a view taken in the direction of arrows AA in (A). , (C) is a partially cut front view showing a state in which a spring member has been extended by a required dimension, and (d) is a view taken in the direction of arrows BB in (c). An example of the conventional concrete pump vehicle with a boom is shown, (A) is a schematic perspective view, (B) is a figure which expands and shows the front-end | tip part of a boom.

Explanation of symbols

3 Rotating frame 4 Boom 8 Concrete piping 9 Root hose (concrete discharge hose)
11 Tip hose (concrete discharge hose)
DESCRIPTION OF SYMBOLS 12 Support member 13 Load indicator 21 Holding member 22 Cord-like object 23 Spring member 24 Display part

Claims (4)

With a boom that supports a concrete pipe on a multistage boom that can be raised and lowered on a swivel frame, and hangs a concrete discharge hose connected to the tip side of the concrete pipe from the tip side of the boom Between the tip of the boom in a concrete pump truck and a support member attached to support the load of the suspended portion of the hose at a position near the upper end of the concrete discharge hose suspended from the tip of the boom, A scale-shaped load indicator having a display for displaying the magnitude of the load of the concrete discharge hose is interposed, and the support member is suspended from the tip of the boom via the load indicator. , the load indicator attached to the distal end side and the support member of the boom, the load of the depending portion of the concrete discharge hose, A boom-equipped concrete characterized in that it is supported on the tip side of the boom via a support member and a load indicator so that the load of the hanging portion of the hose can be displayed on the indicator of the load indicator. Boom overload prevention device for pump cars.   The scale-shaped load indicator is connected to the upper end side and lower end side connecting members arranged in the vertical direction with a spring member interposed therebetween, and the upper end side connecting member is supported on the tip end side of the boom. A spring balance type load display that allows the spring member to expand and contract in accordance with the load acting on the lower end side connecting member and displays the magnitude of the load on the display unit based on the amount of deformation of the spring member. The boom overload prevention device for a concrete pump truck with a boom according to claim 1, wherein the boom is overloaded.   The scale-shaped load indicator is provided with a display window, a fixed display member, and a slide member that can be slid by expansion and contraction of the spring member, and has different colors that can recognize the outer surface of the display member and the outer surface of the slide member. 3. The boom overload prevention device for a concrete pump vehicle with a boom according to claim 2, wherein the boom is provided with a display unit that can display the magnitude of the load of the hanging portion of the concrete discharge hose by changing the display color.   A holding member that can support the load of the hanging portion of the concrete discharge hose, and is attached and held at a location that is a required distance away from the support member at the tip side of the hanging portion of the concrete discharge hose. 4. The boom overload prevention device for a concrete pump vehicle with a boom according to claim 1, wherein the members are connected by a cord-like object having a dimension slightly longer than a hose length between the support member and the holding member.

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