Mixer vehicle

Abstract

To improve maintenance workability.SOLUTION: A mixer vehicle 1A having a mixer drum 2 rotatably mounted on the vehicle includes: an engine 10; a drive unit 4 that includes a hydraulic pump 5 driven by the engine 10 to discharge hydraulic oil, and a hydraulic motor 6 operated by hydraulic oil supplied from the hydraulic pump 5 to rotate the mixer drum 2; a drive shaft 8 that transmits power from the engine 10 to the drive unit 4; body frames 12 that are arranged on both sides of the drive shaft 8 in the left and right direction of the vehicle; a front step 20 that is bridged from one side of the body frame 12 to the other side across the drive shaft 8 and is supported rotatably in a cantilevered manner; a cover 21 that is connected to a rear side of the front step 20 and covers the drive shaft 8; and a stay 40 that holds the front step 20 in a state where it is opened by a predetermined degree.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a mixer vehicle. [Background technology]

[0002] Patent Document 1 discloses a mixer vehicle in which hydraulic oil is supplied from a hydraulic pump connected to a power take-off shaft of an engine to a hydraulic motor, and the hydraulic motor drives and rotates a mixer drum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-66292 Summary of the Invention [Problem to be solved by the invention]

[0004] The engine's power take-off shaft and the mixer drum drive unit can be connected via a drive shaft. In this case, if a scaffolding is placed above the drive shaft, maintenance work on the drive unit and cleaning of the mixer drum can be performed from the scaffolding, improving workability. Furthermore, by covering the drive shaft, safety against entanglement can be ensured.

[0005] However, the drive shaft requires maintenance work such as greasing to lubricate it and prevent wear, while the cover is secured with bolts, which means that maintenance work must be performed after removing the bolts, making the work inefficient.

[0006] The present invention has been made in view of the above problems, and has as its object to improve the ease of maintenance work. [Means for solving the problem]

[0007] The present invention is a mixer vehicle having a mixer drum rotatably mounted on a vehicle, and is characterized by comprising: a drive source for the mixer drum; a drive unit having a fluid pressure pump driven by the drive source and discharging working fluid, and a fluid pressure motor operated by the working fluid supplied from the fluid pressure pump and rotating the mixer drum; a drive shaft that transmits power from the drive source to the drive unit; body frames arranged on both sides of the drive shaft in the left-right direction of the vehicle; scaffolding that spans the drive shaft from one side of the body frame to the other and is rotatably supported in a cantilevered manner; a cover connected to the back side of the scaffolding and covering the drive shaft; and a holding mechanism that holds the scaffolding in an open state at a predetermined opening angle.

[0008] According to this invention, the platform can be opened and closed together with the cover, making it easy to access the drive shaft. In addition, the platform can be kept open to a predetermined degree, ensuring maintenance space.

[0009] Furthermore, the present invention is characterized in that the holding mechanism is a stay having a rotational support portion provided on one end side and rotatably supported on a platform member provided on the vehicle frame, and a hook portion provided on the other end side that engages with the scaffolding when it is opened to a predetermined opening degree and supports the scaffolding from the back side.

[0010] According to this invention, the scaffolding can be held in an open position simply by engaging the hook portion of the stay with the scaffolding. In addition, because the stay supports the scaffolding from the back side, i.e., by leaning toward the drive shaft, maintenance space can be secured even if there is not enough space to open the scaffolding wide.

[0011] The present invention is also characterized in that it further comprises a locking mechanism that locks the scaffolding in a closed state.

[0012] According to this invention, by locking the scaffolding except when maintenance work is being performed, it is possible to prevent the scaffolding from vibrating or generating noise while the vehicle is traveling. Furthermore, when maintenance work is to be performed, the scaffolding can be opened and closed together with the cover simply by unlocking the scaffolding.

[0013] The present invention is also characterized in that the hook portion is fixed to the stay fixing portion when the scaffolding is closed, and the stay fixing portion has a base provided on the edge of the scaffolding, a hook locking portion formed in the base as a notch and to which the hook portion is locked, and a magnet provided on the base and which attracts the stay when the hook portion is locked to the hook locking portion.

[0014] According to this invention, noise caused by rattling of the stay while the vehicle is running can be suppressed, and the stay can be easily fixed and detached. [Effects of the Invention]

[0015] According to these inventions, the ease of maintenance work can be improved. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a plan view of a mixer vehicle according to an embodiment of the present invention, viewed from above. FIG. [Figure 2] FIG. 2 is a perspective view showing the drive shaft and its surroundings with the front step closed; [Figure 3] FIG. 2 is a perspective view showing the drive shaft and its surroundings with the front step open; [Figure 4] FIG. 1 is a first diagram showing a main part of a mixer vehicle according to a first modified example. [Figure 5] FIG. 2 is a second diagram showing a main part of the mixer vehicle according to the first modified example. [Figure 6] FIG. 10 is a first diagram showing a main part of a mixer vehicle according to a second modified example. [Figure 7] FIG. 2 is a second diagram showing a main part of the mixer vehicle according to the second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0018] As shown in FIG. 1, the mixer truck 1A is a vehicle that transports ready-mixed concrete (hereinafter referred to as "ready-mixed concrete") such as mortar or ready-mixed concrete that has been placed in a mixer drum 2, which is a mounted object, and includes a driver's cab 11, a body frame 12 that extends in the fore-and-aft direction of the vehicle, and a front support frame 3 that is mounted on the body frame 12 and supports the front of the mixer drum 2. The body frame 12 has a right body frame 12a on the right side of the vehicle and a left body frame 12b on the left side of the vehicle, and the front support frame 3 has a right front support frame 3a on the right side of the vehicle and a left front support frame 3b on the left side of the vehicle. The following explanation will be given for the case where the mixer truck 1A is loaded with ready-mixed concrete.

[0019] The mixer vehicle 1A is equipped with a mixer drum 2 rotatably mounted on the vehicle. The mixer drum 2 is a cylindrical container with a bottom that is rotatably mounted on the vehicle body frame 12 (on the vehicle), and has an opening 2a at its rear end through which ready-mixed concrete is charged and discharged. The mixer drum 2 is mounted with its rotation axis O tilted so that it gradually rises from the front to the rear of the vehicle. Inside the mixer drum 2, a drum blade (not shown) is arranged spirally along the inner wall surface of the drum, and the ready-mixed concrete loaded inside the mixer drum 2 is mixed by the drum blade rotating together with the mixer drum 2.

[0020] The mixer drum 2 is driven to rotate via a drive unit 4 using a traveling engine 10 mounted on the mixer vehicle 1A as a drive source. The drive unit 4 is a fluid pressure device that is driven by the rotation of the engine 10 and drives the mixer drum 2 to rotate by the fluid pressure of a working fluid. The rotation of the engine 10 is transmitted to the drive unit 4 via a PTO shaft 9 (PTO: Power take-off) that constantly extracts power from the engine 10 during operation, and a drive shaft 8 that transmits power from the engine 10 to the drive unit 4.

[0021] The drive shaft 8 is provided behind the engine 10 in the vehicle's longitudinal direction and extends along the vehicle's longitudinal direction. The drive shaft 8 connects the PTO shaft 9 and the drive unit 4, thereby transmitting power input from the engine 10 via the PTO shaft 9 to the drive unit 4.

[0022] The drive device 4 has a hydraulic pump 5 as a fluid pressure pump that is driven by the engine 10 and discharges hydraulic oil, and a hydraulic motor 6 as a fluid pressure motor that is operated by the hydraulic oil supplied from the hydraulic pump 5 and rotates the mixer drum 2.

[0023] The hydraulic pump 5 is driven to rotate by power constantly extracted from the operating engine 10 via the PTO shaft 9. When the mixer drum 2 is rotated forward by the hydraulic pump 5, the ready-mixed concrete inside the mixer drum 2 is agitated. On the other hand, when the mixer drum 2 is rotated reversely by the hydraulic pump 5, the ready-mixed concrete inside the mixer drum 2 is discharged to the outside through the opening 2a at the rear end.

[0024] The hydraulic motor 6 is rotationally driven by the hydraulic oil supplied from the hydraulic pump 5. The output shaft of the hydraulic motor 6 is the output shaft of the drive unit 4, and is connected to the rotation shaft O of the mixer drum 2 via a reducer 7.

[0025] The drive source that drives the drive device 4 is not limited to the engine 10 for traveling, but may be, for example, an engine for accessories not used for traveling or an electric motor. Also, the drive device 4 may use other incompressible fluids as the working fluid instead of hydraulic oil.

[0026] 2 and 3 are perspective views showing the periphery of the drive shaft 8. Fig. 2 shows a state in which the front step 20, which will be described next, is closed, and Fig. 3 shows a state in which the front step 20 is opened.

[0027] As shown in FIGS. 2 and 3 , body frames 12 are disposed on both sides of the drive shaft 8 in the left-right direction of the vehicle, and a front step 20 serving as a foothold is installed between one side of the body frame 12 and the other. The front step 20 is a plate-like member made of, for example, a steel plate, and has a rectangular shape. The front step 20 is installed with its longitudinal direction aligned with the left-right direction of the vehicle and has a boarding section 20a on which a user stands, and edge sections 20b, 20c that are bent downward from the boarding section 20a in a step-like shape and extend in the longitudinal direction. A user can stand on the front step 20 when performing maintenance work on the drive unit 4 or cleaning work on the mixer drum 2.

[0028] The drive shaft 8 is covered with a cover 21. The cover 21 covers the periphery of the drive shaft 8 at the portion where the front step 20 is placed. By covering the drive shaft 8 with the cover 21, safety is ensured against getting caught in the drive shaft 8. The cover 21 also serves to prevent grease from scattering from the drive shaft 8 to the surrounding area.

[0029] 3, the drive shaft 8 has a first shaft 8a and a second shaft 8b connected to the first shaft 8a so as to be freely movable in the axial direction, and the first shaft 8a and the second shaft 8b have a connecting portion 8c where they are connected to each other. The connecting portion 8c is connected by, for example, a spline connection, and allows the drive shaft 8 to expand and contract. In addition, cross joints (universal joints) 8d, 8e are provided at both ends of the drive shaft 8.

[0030] The connecting portion 8c and the cross joints 8d and 8e act to absorb displacement that occurs in the drive shaft 8 while the vehicle is running, and these parts require greasing for lubrication and to prevent wear. The drive shaft 8 also requires maintenance work, such as checking for loose bolts.

[0031] In this embodiment, the front step 20 is rotatably supported in a cantilevered manner, and the cover 21 is connected to the back side of the front step 20. The front step 20 has, in the longitudinal direction, one end 20d that is rotatably supported by the support member 31 via a hinge 22, and the other end 20e that abuts against the support member 32 in the closed state shown in FIG. 2. By raising and lowering the other end 20e, the front step 20 rotates around the rotation axis of the hinge 22 provided at the one end 20d, thereby opening and closing. The cover 21 is connected to the back side of the front step 20 by bolting.

[0032] Therefore, the front step 20 can be opened and closed together with the cover 21, which allows easy access to the drive shaft 8 when performing maintenance work on the drive shaft 8.

[0033] The cover 21 has an upper cover 21a that covers the top of the drive shaft 8, and side covers 21b and 21c that are attached to the upper cover 21a and cover both left and right sides of the drive shaft 8. The upper cover 21a is made of a rectangular plate-like member, and both left and right ends of the vehicle are bent into a U-shape. The side covers 21b and 21c are fastened with bolts to the U-shaped bent part of the upper cover 21a, and the upper cover 21a is fastened with bolts to the back side of the front step 20.

[0034] The top cover 21a is made of a material (for example, steel plate) that is stronger than the side covers 21b and 21c, and the side covers 21b and 21c are made of a material (for example, resin) that is lighter than the top cover 21a. Therefore, the top cover 21a ensures the strength of the cover 21 against loads from above, and the side covers 21b and 21c reduce the weight when opening and closing the front step 20 together with the cover 21.

[0035] As shown in Fig. 3, the mixer vehicle 1A further includes a stay 40 as a retention mechanism that retains the front step 20 in an open state at a predetermined opening angle. The predetermined opening angle is based on the state in which the front step 20 is closed (the state shown in Fig. 2), and is set to an opening angle that is less than 90 degrees and that allows maintenance space for the drive shaft 8 to be secured (for example, 60 degrees or more). By setting the predetermined opening angle to less than 90 degrees, it is possible to secure maintenance space for the drive shaft 8 even when there is not enough space to open the front step 20 widely.

[0036] Stay 40 is formed of a round bar-shaped member, and as shown in Fig. 3, has a rotation support portion 40a provided at one end (base end) and rotatably supported by support member 33, and a hook portion 40b provided at the other end (tip end) and engaged with front step 20 when it is opened to a predetermined opening angle to support front step 20 from the back side. Support member 33 is a platform member (a mating member provided on body frame 12) provided on body frame 12, and has an L-shaped support member 331 fixed to support member 32 and a cylindrical collar 332 bolted to support member 331. Support members 31, 32 and a support member 34 described later can also be called platform members.

[0037] The rotation support portion 40a is formed by bending one end of the stay 40 into a circular shape that follows the outer periphery of the collar 332 of the support member 33. The position of the rotation support portion 40a in the vehicle longitudinal direction is aligned with the edge portion 20c of the front step 20.

[0038] The hook portion 40b is formed by bending the other end of the stay 40 into a fishhook shape. An elongated hole 20ca for engaging the hook portion 40b is formed in the tip (the end opposite the hinge 22) of the edge portion 20c of the front step 20, and the hook portion 40b is engaged in the elongated hole 20ca from the back side of the front step 20 when the front step 20 is opened to a predetermined opening angle of less than 90 degrees.

[0039] As a result, the front step 20 is supported from the back side by the hook portion 40b while leaning toward the drive shaft 8. Therefore, when performing maintenance work on the drive shaft 8, the front step 20 can be held in an open position simply by engaging the stay 40 with the front step 20. Furthermore, because the stay 40 supports the front step 20 from the back side, that is, while leaning toward the drive shaft 8, maintenance space can be secured even if there is not enough space to open the front step 20 widely. The angle at which the front step 20 is opened can be set by the length of the stay 40.

[0040] As shown in FIG. 2, the hook portion 40b is fixed to the stay fixing portion 41 when the front step 20 is closed. The stay fixing portion 41 has a base 41a provided on the edge portion 20c of the front step 20, a hook locking portion 41b formed in the base 41a as a notch and for locking the hook portion 40b, and a magnet 41c provided on the base 41a and for attracting the stay 40 when the hook portion 40b is locked to the hook locking portion 41b. The base 41a is made of a piece of plate-like material, and the hook locking portion 41b is formed in a notch shape along the left-right direction of the vehicle. The magnet 41c attracts a portion 40c of the stay 40 in front of the hook portion 40b.

[0041] The hook locking portion 41b and the magnet 41c suppress noise caused by rattling of the stay 40 while the vehicle is traveling. By locking the hook portion 40b of the stay 40 to the hook locking portion 41b, rattling of the stay 40 in the fore-and-aft direction of the vehicle while traveling is suppressed. In addition, by attracting the stay 40 with the magnet 41c, rattling of the stay 40 in the up-and-down direction of the vehicle while traveling is suppressed, and the stay 40 can be easily fixed and detached.

[0042] The mixer vehicle 1A further includes a catch clip 50 as a locking mechanism that locks the front step 20 in a closed state. The catch clip 50 is provided on the front step 20 and the support member 32, and includes a base 51 attached to the other end 20e of the front step 20, a receiving member 52 attached to the support member 32, an engagement shaft 53 engaged with the receiving member 52, and an operating lever 54 that can be rotated in a direction (locking direction) to lock the front step 20 to the support member 32 with the engagement shaft 53 engaged with the receiving member 52. The front step 20 is locked by releasably securing the front step 20 to the support member 32 in a closed state.

[0043] With the front step 20 closed, operating the operating lever 54 to hook the engagement shaft 53 onto the receiving member 52 and then rotating the operating lever 54 in the locking direction locks the front step 20 to the support member 32. By locking the front step 20 except when maintenance work is being performed on the drive shaft 8, it is possible to prevent the front step 20 from vibrating or generating noise while the vehicle is running.

[0044] When the front step 20 is locked by the catch clip 50, rotating the operating lever 54 in the unlocking direction, opposite the locking direction, disengages the engagement shaft 53 from the receiving member 52. This releases the connection between the front step 20 and the support member 32, making it possible to open the front step 20. Therefore, when performing maintenance work on the drive shaft 8, the front step 20 can be opened and closed together with the cover 21 simply by unlocking the front step 20.

[0045] The procedure for opening the front step 20 is as follows. First, remove the hook portion 40b of the stay 40 from the stay fixing portion 41 and rotate it to a position where it does not interfere with the front step 20. Next, operate the catch clip 50 to unlock the front step 20, and rotate the front step 20 to approximately the predetermined opening angle while lifting the other end portion 20e of the front step 20. Then, with the front step 20 rotated to approximately the predetermined opening angle, engage the hook portion 40b with the elongated hole 20ca.

[0046] As a result, the front step 20, together with the cover 21, is supported by the stay 40 in an open state at a predetermined opening angle, ensuring space for maintenance of the drive shaft 8. Furthermore, because maintenance work on the drive shaft 8 can be performed with the front step 20 open, it is possible to avoid situations where the front step 20 used as a foothold becomes dirty or slippery due to accidentally getting grease on it. Note that when closing the front step 20, the work can be done in reverse order.

[0047] Next, modifications of the mixer vehicle 1A will be described with reference to FIGS.

[0048] (First Modification) Figures 4 and 5 are diagrams showing the main parts of a mixer vehicle 1B according to the first modified example. Figure 4 shows the main parts of the mixer vehicle 1B as seen from the front of the vehicle with the front step 20 closed, and Figure 5 shows the main parts of the mixer vehicle 1B as seen from the rear of the vehicle (i.e., from the opposite side to Figure 4) with the front step 20 open.

[0049] 4 and 5, the mixer vehicle 1B is provided with a magnetic stopper 60 as a holding mechanism instead of the stay 40. The magnetic stopper 60 includes a magnet 61 and a bracket 62 that causes the magnet 61 to abut against the support member 34 when the front step 20 is opened to a predetermined opening angle, which is, for example, 90 degrees or more.

[0050] One end of the bracket 62 is provided at the base end (the end on the hinge 22 side) of the edge 20c of the front step 20, and a magnet 61 is provided at the other end of the bracket 62. The bracket 62 is bent so that the magnet 61 abuts against the support member 34 when the front step 20 is opened to a predetermined angle. The support member 34 has a vertical surface 34a that is perpendicular to the upper surface of the front step 20 in the closed state, and the magnet 61 abuts against and is attracted to the vertical surface 34a. The support member 34 has a support member 31 for the hinge 22 installed thereon.

[0051] The magnet 61 functions as a stopper against which the front step 20 comes into contact when it is opened to the predetermined opening degree, thereby preventing the front step 20 from rotating further in the opening direction together with the bracket 62. The magnet 61 also functions as a restricting member that restricts the rotation of the front step 20 toward the drive shaft 8 when it is opened to the predetermined opening degree by holding the front step 20 by attraction when it is opened to the predetermined opening degree.

[0052] In other words, the magnet 61 provided on the bracket 62 serves both as a stopper against which the front step 20 abuts when opened to a predetermined degree, and as a restricting member that restricts the rotation of the front step 20, when opened to the predetermined degree, toward the drive shaft 8. In other words, the magnetic stopper 60 has such a stopper and restricting member.

[0053] The magnetic stopper 60 can also hold the front step 20 in an open state at a predetermined angle, ensuring maintenance space for the drive shaft 8. Furthermore, because the magnet 61 restricts the rotation of the front step 20 toward the drive shaft 8, the front step 20 can be held in a nearly vertical position, ensuring maintenance space even when there is not enough space to open the front step 20 wide enough to open it more than 90 degrees.

[0054] (Second Modification) 6 and 7 are diagrams showing the main parts of a mixer vehicle 1C according to a second modified example. Fig. 6 shows the main parts of the mixer vehicle 1C with the front step 20 closed, and Fig. 7 shows the main parts of the mixer vehicle 1C with the front step 20 open.

[0055] 6 and 7, the mixer vehicle 1C is provided with a stopper 70 with a rotating stay as a holding mechanism instead of the stay 40. The stopper 70 with a rotating stay includes a base 71 attached to the support member 34, a stopper 72 attached to the base 71 and abutting against the front step 20 when the front step 20 is opened to a predetermined opening angle, a rotating stay 73 attached to the base 71 and rotatable to a position facing the front step 20 from the opposite side of the stopper 72 when the front step 20 is opened to the predetermined opening angle, and a butterfly bolt 74 as a hand-tightened fastening member for securing the rotating stay 73, the predetermined opening angle being, for example, 90 degrees or more. The butterfly bolt 74 is inserted into one end of the rotating stay 73, and the other end of the rotating stay 73 is bent into an L-shape to facilitate rotation.

[0056] The base 71 is formed of a plate-like member made of, for example, a steel plate, and has: a fixed portion 71a that is fixed to the support member 34; an inclined portion 71b that is bent from the fixed portion 71a and inclined so as to be parallel to the edge portion 20c of the front step 20 when it is opened to a predetermined opening angle; and a stay attachment portion 71c that is formed by bending the side of the inclined portion 71b opposite the riding portion 20a of the front step 20 in a step shape toward the surface on which the stopper 72 is provided. A rotating stay 73 is fixed to the stay attachment portion 71c with a butterfly bolt 74, and the rotating stay 73 is fixed in a position that does not interfere with the front step 20, which is opened or closed, except during maintenance work on the drive shaft 8.

[0057] The stopper 70 with a rotating stay is used as follows when performing maintenance work on the drive shaft 8. That is, when performing maintenance work on the drive shaft 8, the front step 20 is first opened and brought into contact with the stopper 72. This causes the front step 20 to lean against the stopper 72 and open to a predetermined opening angle.

[0058] Next, the butterfly bolt 74 is loosened and the rotating stay 73 is rotated so that the tip end (other end) of the rotating stay 73 faces the edge 20c of the front step 20. In this state, the butterfly bolt 74 is manually tightened to again fix the rotating stay 73. This places the rotating stay stopper 70 in the state shown in FIG. 7, and rotation of the front step 20 toward the drive shaft 8 when it is opened to the predetermined angle is restricted.

[0059] The stopper 70 with a rotating stay has a stopper 72 against which the front step 20 abuts when opened to a predetermined opening degree, so as with the first modified example, maintenance space for the drive shaft 8 can be secured. Furthermore, the stopper 70 with a rotating stay has a rotating stay 73 as a restricting member that restricts the rotation of the front step 20 toward the drive shaft 8 when opened to a predetermined opening degree, so as with the first modified example, the front step 20 can be held in a nearly vertical position. Therefore, maintenance space can be secured even when there is not enough space to open the front step 20 widely. Furthermore, the stopper 70 with a rotating stay holds the front step 20 between the stopper 72 and the rotating stay 73, so the front step 20 can also be held at an opening angle of less than 90 degrees.

[0060] The configuration, operation, and effects of the embodiment of the present invention will be described below.

[0061] Each of the mixer vehicles 1A, 1B, and 1C includes a mixer drum 2 rotatably mounted on a vehicle. The mixer vehicles 1A, 1B, and 1C include an engine 10 as a drive source for the mixer drum 2, a drive unit 4 including a hydraulic pump 5 driven by the engine 10 and discharging hydraulic oil, and a hydraulic motor 6 operated by the hydraulic oil supplied from the hydraulic pump 5 and rotating the mixer drum 2, a drive shaft 8 that transmits power from the engine 10 to the drive unit 4, body frames 12 arranged on both sides of the drive shaft 8 in the left-right direction of the vehicle, a front step 20 that spans the drive shaft 8 from one side to the other of the body frames 12 and is rotatably supported in a cantilevered manner, a cover 21 connected to the back side of the front step 20 and covers the drive shaft 8, and a stay 40, a magnet-equipped stopper 60, or a rotary stay-equipped stopper 70 as a holding mechanism that holds the front step 20 in an open state at a predetermined angle.

[0062] According to this configuration, the front step 20 is opened and closed together with the cover 21, facilitating access to the drive shaft 8. Furthermore, since the front step 20 is held in an open state at a predetermined opening angle, maintenance space can be secured.

[0063] The stay 40 serving as a holding mechanism has a rotation support portion 40a provided at one end and rotatably supported on a support member 33 serving as a frame upper member provided on the body frame 12, and a hook portion 40b provided at the other end and engaged with the front step 20 when it is opened to a predetermined opening angle to support the front step 20 from the back side.

[0064] According to this configuration, the front step 20 can be held in an open position simply by engaging the hook portion 40b of the stay 40 with the front step 20. Furthermore, since the stay 40 supports the front step 20 from the rear side, that is, by supporting it in a state in which it is leaning toward the drive shaft 8, maintenance space can be secured even if there is not enough space to open the front step 20 wide.

[0065] The mixer vehicles 1A, 1B, and 1C further include a catch clip 50 as a locking mechanism for locking the front step 20 in the closed state.

[0066] According to this configuration, by locking the front step 20 except when maintenance work is being performed on the drive shaft 8, it is possible to prevent the front step 20 from vibrating or generating noise while the vehicle is running. Furthermore, when maintenance work is being performed on the drive shaft 8, the front step 20 can be opened and closed together with the cover 21 simply by unlocking the front step 20.

[0067] In the mixer vehicle 1A, the hook portion 40b is fixed to the stay fixing portion 41 when the front step 20 is closed, and the stay fixing portion 41 has a base 41a provided on the edge portion 20c of the front step 20, a hook locking portion 41b formed in a notch shape in the base 41a and to which the hook portion 40b is locked, and a magnet 41c provided on the base 41a and which attracts the stay 40 when the hook portion 40b is locked to the hook locking portion 41b.

[0068] This configuration can suppress noise caused by rattling of the stay 40 while the vehicle is running, and also makes it easier to fix, attach, and detach the stay 40.

[0069] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0070] 1A, 1B, 1C... mixer vehicle, 4... drive unit, 5... hydraulic pump (fluid pressure pump), 6... hydraulic motor (fluid pressure motor), 8... drive shaft, 10... engine (drive source), 20... front step (foothold), 21... cover, 40... stay (retention mechanism), 40a... rotation support part, 40b... hook part, 50... catch clip (lock mechanism), 60... stopper with magnet (retention mechanism), 70... stopper with rotation stay (retention mechanism)

Claims

1. A mixer vehicle having a mixer drum rotatably mounted on the vehicle, a drive source for the mixer drum; a drive unit including a fluid pressure pump driven by the drive source and discharging a working fluid, and a fluid pressure motor operated by the working fluid supplied from the fluid pressure pump and rotating the mixer drum; a drive shaft that transmits power from the drive source to the drive device; a vehicle body frame disposed on both sides of the drive shaft in the left-right direction of the vehicle; a scaffolding that is bridged across the drive shaft from one side of the vehicle body frame to the other side and is rotatably supported in a cantilevered manner; A cover connected to the back side of the scaffolding and covering the drive shaft; A mixer truck characterized by comprising: a holding mechanism that holds the scaffolding in an open state at a predetermined opening angle.

2. The mixer vehicle according to claim 1, The holding mechanism is a stay having a rotation support part provided on one end side and rotatably supported on a platform upper member provided on the vehicle body frame, and a hook part provided on the other end side and engaged with the scaffolding in a state where the scaffolding is opened to the predetermined opening degree to support the scaffolding from the back side. A mixer truck characterized by:

3. The mixer vehicle according to claim 1 or 2, Further provided is a locking mechanism for locking the scaffold in a closed state. A mixer truck characterized by:

4. The mixer vehicle according to claim 2, The hook portion is fixed to the stay fixing portion when the scaffolding is closed, The stay fixing portion includes a base provided on the edge of the scaffolding, a hook locking portion formed in the base in a notch shape and adapted to lock the hook portion; a magnet provided on the base and adapted to attract the stay when the hook portion is engaged with the hook engaging portion, A mixer truck characterized by:

Images