Load-mounted mixer unit

Abstract

To provide an easily treatable new mixer unit with a simple structure in which the defect of the conventional mixer unit is improved while maintaining the function and performance thereof.SOLUTION: A mixer unit 1 can be conveyed in a state of being stacked on a truck bed and comprises: an engine 12 driving a hydraulic pump 14 feeding pressure oil to a hydraulic motor 10 rotating a drum 2; a switching valve 15 installed in a hydraulic circuit between the hydraulic pump 14 and the hydraulic motor 10; an operation lever 16 operating the engine 12 and the switching valve 15; and a frame 50 installed with these apparatuses. The operation lever 16 is operated laterally to reverse the rotation direction of the drum 2, and also, the operation lever 16 is operated vertically to change the rotation frequency of the drum 2 high and low.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The disclosed technology relates to a small mixer unit that can be handled in the same way as a truck mixer by being loaded on the loading platform of a truck.

Background Art

[0002] There are many areas where the road width is narrow and there are many roads that cannot be passed by a normal truck mixer (so-called mixer truck). In such areas, instead of a truck mixer, a small mixer unit as disclosed in Patent Document 1 has been used since before.

[0003] By loading the mixer unit on the loading platform of a small truck (so-called 2t truck, etc.), it can be handled in the same way as a truck mixer, and it becomes possible to transport fresh concrete even on a narrow road. Moreover, since the mixer unit can be unloaded from the loading platform of the truck, it is also excellent in convenience.

[0004] A conventional mixer unit has a frame sized to be loaded on the loading platform of a small truck. And various devices constituting a truck mixer, such as a drum, a hopper, a chute, an engine, a hydraulic pump, a hydraulic motor, a fuel tank, and an oil tank, are intensively assembled and assembled on the frame.

[0005] The operation of the mixer unit is performed manually. That is, by operating a lever equipped on the mixer unit, the engine drives the hydraulic pump. Then, the pressurized oil (hydraulic oil) obtained thereby is supplied to the hydraulic motor, and the drum can be rotated. The switching of the rotation direction of the drum (stirring and discharging), and the switching of the rotation speed of the drum (high-speed rotation and low-speed rotation) can also be performed by operating the lever.

[0006] The mixer unit of Patent Document 1 also discloses storing water in the cavity inside the frame and using the frame as a water tank.

Prior Art Documents

[0007] [Patent Document 1] Japanese Patent Application Publication No. 53-88018 [Overview of the project] [Problems that the invention aims to solve]

[0008] As disclosed in Patent Document 1 mentioned above, in conventional mixer units, the rotation of the drum can be started and stopped, and the direction and speed of the drum's rotation can be switched by operating a lever.

[0009] Figure 9 shows a simplified diagram of the lever 100 that performs the switching operation. The right-hand diagram in Figure 9 is a schematic cross-sectional view taken along the line I-I of the left-hand diagram. The lever 100 is pivotally supported on a box-shaped support base 101 and is configured to swing in the directions of arrows Y1 and Y2 in the left-hand diagram of Figure 9.

[0010] A first rod 102, which operates the engine's accelerator, is connected to the lever 100. By swinging the lever 100 in the direction of Y1, the first rod 102 also slides in the direction of Y1 in conjunction with it. A second rod, which operates the control valve, is connected to the first rod 102 perpendicularly. By swinging the lever 100 in the direction of Y2, the first rod 102 rotates, and the second rod slides in the direction of Y2 in conjunction with it.

[0011] The lever position P1, indicated by the dashed line, is the stop position. In this state, when the lever 100 is not tilted in the direction of Y2, the control valve is in neutral. Therefore, no pressurized oil is supplied to the hydraulic motor. After starting the engine, operating the lever 100 to lever position P2 allows the engine to reach a predetermined output, enabling the hydraulic pump to supply pressurized oil that can rotate the drum.

[0012] By tilting lever 100 to one side in the direction of Y2, the control valve switches the direction of flow of pressurized oil from neutral, causing the drum to rotate forward (agitation). Increasing the tilt of lever 100 increases the flow rate of pressurized oil and increases the rotation speed of the drum. Conversely, by tilting lever 100 to the other side in the direction of Y2, the control valve switches the direction of flow of pressurized oil from neutral, causing the drum to rotate backward (discharge). Increasing the tilt of lever 100 increases the flow rate of pressurized oil and increases the rotation speed of the drum.

[0013] To perform these operations using hydraulic control, conventional mixer units use a combined pump consisting of two hydraulic pumps and a corresponding control valve. By switching the control valve with a lever, both the direction and flow rate of the pressurized oil supplied to the hydraulic motor are switched.

[0014] Conventional mixer units, because they use a combined pump and a corresponding specific control valve, have many components and complex hydraulic circuits. Moreover, because a specific control valve is required, it can be difficult to obtain the necessary control valve when needed.

[0015] Incidentally, production of the corresponding control valve has been discontinued at this time. As a result, new control valves are unavailable, and it is currently not possible to install new mixer units in the same configuration as before.

[0016] After using a mixer unit, it is necessary to immediately rinse it with water to wash away any fresh concrete adhering to the drum and chute. This requires a relatively large amount of washing water on site, but such mixer units have limited installation space and weight capacity.

[0017] Therefore, conventional mixer units use the frame as a water tank. However, in this case, the frame is prone to corrosion, which is disadvantageous in terms of strength and durability. Draining the water is also difficult, and the inside of the frame remains constantly wet, which accelerates corrosion.

[0018] Therefore, the disclosed technology aims to improve upon these shortcomings while maintaining the functionality and performance of conventional mixer units, and to provide a new mixer unit with a simple structure and ease of use. [Means for solving the problem]

[0019] The disclosed technology relates to a mixer unit that can be loaded onto the bed of a truck for transport.

[0020] The mixer unit comprises a drum that agitates the contained ready-mix concrete by rotating forward and discharges the ready-mix concrete by rotating backward; a hydraulic motor that rotates the drum; a piston pump that supplies pressurized oil to the hydraulic motor; an engine that drives the piston pump; a switching valve installed in the hydraulic circuit between the piston pump and the hydraulic motor; an operating lever that operates the engine and the switching valve; and a frame on which the drum, the hydraulic motor, the piston pump, the engine, the switching valve, and the operating lever are installed.

[0021] Then, by operating the operating lever horizontally to switch the switching valve, the flow path of the pressurized oil supplied to the hydraulic motor is changed, thereby reversing the rotation direction of the drum, and by operating the operating lever vertically to displace the accelerator of the engine, the flow rate of the pressurized oil supplied to the hydraulic motor is adjusted, thereby changing the rotation speed of the drum to high or low.

[0022] That is, this mixer unit uses a single piston pump and a switching valve instead of a compound pump composed of two hydraulic pumps and a corresponding specific control valve as in a conventional mixer unit to change the rotation direction and speed of the drum.

[0023] The switching valve is switched by operating the operation lever horizontally, the rotation direction of the drum is changed by changing the flow path of the pressure oil, and the accelerator is displaced by operating the operation lever vertically, and the rotation speed of the drum is changed by adjusting the flow rate of the pressure oil.

[0024] Thereby, since the switching valve only switches the flow path of the hydraulic oil, general-purpose products can be used and are easily available. The rotation speed of the drum is changed by a single piston pump, so the structure can be simplified and realized at a low cost. Along with this, the weight of the mixer unit can also be reduced.

[0025] The operation lever is also easy to handle because it is operated horizontally when the drum is reversed and in the same vertical direction when the rotation speed of the drum is changed. Therefore, while maintaining the functions and performance of the conventional mixer unit, its defects can be improved, and a new mixer unit with a simple structure and easy handling can be provided.

[0026] It is preferable that the mixer unit also includes a water tank for storing washing water, and the water tank is provided on the frame in a state independent of the frame.

[0027] If the frame is used as a water tank as in a conventional mixer unit, the frame is likely to corrode, which is disadvantageous in terms of strength and durability. Draining water is also difficult, and the inside of the frame is always wet, which promotes corrosion.

[0028] On the other hand, by installing the water tank in a state independent of the frame, that is, separately from the frame, deterioration of the frame can be prevented. Since the water tank can be made of a material different from that of the frame, weight reduction and water resistance can also be improved.

[0029] In such cases, it is even more preferable to further include a water pump connected to the water tank via an upstream water supply path, and a cleaning nozzle connected to the water pump via a downstream water supply path, wherein an on / off valve is installed in the upstream water supply path, and a drain valve is installed in the portion between the water pump and the upstream end of the downstream water supply path.

[0030] During the coldest winter months, the cleaning water inside the water pump may freeze. If a large amount of cleaning water is stored in the water tank, high water pressure is applied to the water pump, making it prone to becoming saturated with cleaning water. If the cleaning water inside the water pump freezes under these conditions, it may damage the water pump.

[0031] In contrast, this mixer unit allows for draining the water pump. Specifically, by closing the on / off valve and operating the drain valve, the water can be drained. With the nozzle of the cleaning nozzle open in this state, the cleaning water inside the water pump can be discharged. [Effects of the Invention]

[0032] According to the disclosed technology, it is possible to provide a mixer unit that is simple in structure and easy to handle, while achieving the same functionality and performance as conventional mixer units, thanks to a simplified hydraulic circuit. [Brief explanation of the drawing]

[0033] [Figure 1] This is a view of the mixer unit from a diagonal upward and forward angle. [Figure 2] This is a view of the mixer unit from the left side. [Figure 3] This is a view of the mixer unit from above. [Figure 4] This is a rear view of the mixer unit. [Figure 5] This is a schematic diagram showing the hydraulic circuit of the mixer unit. [Figure 6] This is a schematic diagram showing the operating mechanism of the mixer unit. [Figure 7] This is a diagram illustrating the operation of the control lever. [Figure 8] This is a schematic diagram showing the water washing equipment included in the mixer unit. [Figure 9] This is a diagram illustrating conventional lever operation. [Modes for carrying out the invention]

[0034] The following describes the disclosed technology. However, the following description is essentially illustrative. The directions used in the description, such as front / back, left / right, and up / down, follow the arrows shown in Figure 1.

[0035] <Mixer Unit> Figure 1 shows a view of the mixer unit 1, to which the disclosed technology is applied, from an oblique angle above and in front. Figure 2 shows a view of the mixer unit 1 from the left side. Figure 3 shows a view of the mixer unit 1 from above. Figure 4 shows a view of the mixer unit 1 from the rear.

[0036] This mixer unit 1 can be transported on the bed of a small truck (a cargo vehicle with a load capacity of less than 2 tons), and is configured to be handled in the same way as a truck mixer. For example, in the case of the example mixer unit 1, the total weight is about 1 ton, the width W in the left-right direction is 1250 mm, the length L in the front-rear direction is 3413 mm, and the height H is 1916 mm. Therefore, it can be driven on the road with the unit loaded on the bed of a typical small truck.

[0037] Mixer unit 1 is equipped with a drum 2, an input hopper 3, an outlet chute 4, an extension chute 5, and other components, similar to a truck mixer. Furthermore, to rotate the drum 2 in the same way as a truck mixer, it is also equipped with a hydraulic motor 10, a hydraulic oil tank 11, an engine 12, a battery 13, a hydraulic pump 14 (piston pump), a switching valve 15, and an operating lever 16. In addition, as will be described in more detail later, it is also equipped with a water washing system consisting of a water tank 30 and a water pump 31, allowing for washing after operation.

[0038] These devices are efficiently mounted on a frame 50 smaller than the area of ​​a small truck bed so that they can be loaded and transported on the truck bed. The frame 50 has an outer frame 51 that is rectangular in shape when viewed from above, support bases 52 provided at various points inside the outer frame 51, and a support frame 53 provided at the rear of the outer frame 51. Each of these outer frame 51, support bases 52, and support frame 53 is formed by joining (welding) hollow rectangular steel pipes, steel plates, pressed steel plates, etc.

[0039] As shown in Figures 2 and 4, the support frame section 53 has a pair of support columns 53a, 53a erected at the left and right rear corners of the outer frame section 51, and an upper beam 53b and a lower beam 53c are installed between these support columns 53a, 53a. A pair of guide rollers 54, 54 that rotatably support the rear of the drum 2 are attached to the lower beam 53c. An input hopper 3 and a V-shaped outlet chute 4 are attached to the upper beam 53b.

[0040] Drum 2 consists of a large container with a cut-edge spindle shape. As shown in Figures 1 and 2, a drive shaft 2a is provided at the center of the front end surface of drum 2. A large-diameter driven sprocket 2b is provided on the outer circumference of the front end surface of drum 2. An annular support ring 2c is provided on the outer circumference of the rear end of drum 2.

[0041] As shown in Figure 2, a block base 55 is provided on a support base 52 (front support base 52a) located on the front part of the frame 50. The block base 55 is located in the center of the frame 50 in the left-right direction. A plummer block 17 is installed on the block base 55. The drive shaft 2a is rotatably supported by this plummer block 17, and as described above, the support ring 2c is supported by a pair of guide rollers 54, 54, so that the drum 2 is supported by the frame 50 in a forward-tilted state.

[0042] A hydraulic motor 10 is installed on the support base 52, adjacent to the left side of the block base 55. A small-diameter drive sprocket is attached to the shaft of the hydraulic motor 10. A ring chain 18 is wrapped around both the drive sprocket and the driven sprocket 2b.

[0043] As shown in Figure 3, a drum opening 2d is formed in the center of the rear end face of the drum 2, communicating with the inside of the drum 2. Although not shown in the illustration, a spiral blade is provided inside the drum 2, which is configured to push the ready-mixed concrete contained in the drum 2 out through the drum opening 2d when the drum 2 rotates in the opposite direction.

[0044] Therefore, when the hydraulic motor 10 rotates forward, the ready-mixed concrete contained in the drum 2 is agitated. Then, when the hydraulic motor 10 rotates in reverse, the ready-mixed concrete is discharged from the drum 2.

[0045] The lower end of the input hopper 3 is connected to the drum opening 2d, and the input hopper 3 is used to load ready-mixed concrete, etc., into the drum 2. The upper end of the outlet chute 4 is also connected to the drum opening 2d, and the outlet chute 4 is used to receive the ready-mixed concrete discharged from the drum 2. The lower end of the outlet chute 4 is located in the center of the frame 50 in the width direction. A step 6 is provided on the left support column 53a, which allows workers to ascend and descend.

[0046] Below the exit chute 4, a foldable extension chute 5 is installed. Specifically, the extension chute 5 is designed to be folded in its middle section. This allows it to be stored in a predetermined space that can be loaded onto the bed of a small truck.

[0047] In its operational state, the extension chute 5 slopes downward from its base to its tip, protruding outward from the side of the frame 50. The base of the extension chute 5 is supported by the frame 50 at the lower part of the lower end of the outlet chute 4, allowing it to swing horizontally, and can be freely positioned from a lateral position to a rearward position as shown by the dashed line in Figure 2.

[0048] (Drive system equipment) In addition to the hydraulic motor 10, the drive system equipment such as the aforementioned hydraulic oil tank 11, engine 12, battery 13, hydraulic pump 14, and switching valve 15 are installed in a consolidated manner on the front support base 52a. Specifically, as shown in Figure 2, a tank stand 56 is provided on the front support base 52a located at the left front corner of the frame 50, and the hydraulic oil tank 11 is installed on the tank stand 56. The battery 13 is installed below the tank stand 56.

[0049] The engine 12 is mounted on a front support base 52a located at the front right corner of the frame 50. This engine 12 is an industrial diesel engine with a maximum output of 7 kW / 2600 rpm. The engine 12 is equipped with a fuel tank of approximately 10 L. The system is configured so that the starter motor is activated by the power of the battery 13 when the engine key and operating lever 16 are operated, and the engine 12 is started.

[0050] The hydraulic pump 14 is installed on the front support base 52a, in the area between the hydraulic oil tank 11 and the engine 12. The input shaft 14a of the hydraulic pump 14 is connected to the output shaft 12a that protrudes from the left side of the engine 12, and the hydraulic pump 14 is driven by the engine 12 and configured to supply pressurized oil to the hydraulic motor 10.

[0051] In this mixer unit 1, a piston pump is used as the hydraulic pump 14. The piston pump reciprocates in accordance with the rotational speed of the engine 12, and discharges a predetermined volume of hydraulic fluid. The displacement volume per rotation of the input shaft is approximately 56 cm³. 3 The minimum allowable rotational speed is 600 rpm, and the maximum allowable rotational speed is 1800 rpm. Furthermore, a type that allows pressure adjustment within the range of 1.2 to 16 MPa is employed.

[0052] The switching valve 15 is a valve that switches the flow path of the hydraulic fluid and is installed in the hydraulic circuit between the hydraulic pump 14 and the hydraulic motor 10. The switching valve 15 has a switching lever 15a, and the flow path of the hydraulic fluid is switched by swinging the switching lever 15a (manual operation). As shown in Figures 1, 2, and 3, the switching valve 15 is installed on the front side of the block base 55 with the swing direction of the switching lever 15a aligned with the left-right direction.

[0053] (Hydraulic circuit) Figure 5 shows the hydraulic circuit provided by this mixer unit 1. The hydraulic circuit includes a first oil supply pipe 61 that sends hydraulic fluid from the hydraulic fluid tank 11 to the hydraulic pump 14, a second oil supply pipe 62 that sends the hydraulic fluid discharged by the hydraulic pump 14 to the switching valve 15, a return oil pipe 63 that returns the hydraulic fluid discharged from the switching valve 15 back to the hydraulic fluid tank 11, and a pair of supply oil pipes 64, 64 that allow hydraulic fluid to flow in and out between the switching valve 15 and the hydraulic motor 10.

[0054] The switching valve 15 switches between a forward flow position, where the hydraulic motor 10 rotates in the forward direction; a closed position, where no hydraulic fluid is supplied to the hydraulic motor 10; and a reverse flow position, where the hydraulic motor 10 rotates in the reverse direction, by swinging the switching lever 15a and holding it at a predetermined angle. This switching valve 15 is a standard type and is readily available. Figure 5 shows the state where the switching lever 15a is in the closed position.

[0055] (operation mechanism) This mixer unit 1 is equipped with an operating mechanism that allows the engine 12 and the switching valve 15 to be operated by operating the operating lever 16, thereby changing the rotation direction and rotation speed of the drum 2. As shown in Figures 1, 2, and 3, the operating mechanism consists of the operating lever 16, operating case 70, support pipe 71, first operating rod 72, second operating rod 73, etc., and its main body is installed along the right edge of the frame 50.

[0056] Figure 6 shows the details of the operating mechanism. The upper diagram in Figure 6 is a schematic view of the operating mechanism from the left, and the lower diagram in Figure 6 is a schematic view of the operating mechanism from above.

[0057] The operating case 70 consists of a box-shaped support base with a roughly U-shaped insertion hole 70a formed on its upper surface, and is positioned at the rear of the right side of the frame 50. The operating lever 16 is pivotally supported inside the operating case 70 with its gripping portion protruding from the insertion hole 70a.

[0058] The operating lever 16 is configured to swing in the left-right and front-back directions along the insertion hole 70a. Specifically, in the lower diagram of Figure 6, the operating lever 16 can swing in the Y1 (horizontal) and Y2 (vertical) directions. The support pipe 71 is installed on the front side of the operating case 70 and extends along the right edge of the frame 50 to the vicinity of the engine 12.

[0059] The first operating rod 72 is slidably and rotatably inserted into the support pipe 71. The rear end of the first operating rod 72 is connected to the operating lever 16 via the rear bracket 74. The front end of the first operating rod 72 is connected to the accelerator 12b of the engine 12 via the front bracket 75.

[0060] A second operating rod 73 is connected to the front end of the first operating rod 72 via a pivot bracket 76, extending perpendicularly to the first operating rod 72. The second operating rod 73 is formed into a predetermined bent shape and is connected to the switching lever 15a of the switching valve 15. The accelerator 12b and the switching lever 15a are displaced in conjunction with the swinging operation of the operating lever 16.

[0061] An operating button 16a is installed at the tip of the operating lever 16 to restrict the operation of the operating lever 16. In other words, when the operating button 16a is not pressed, the link mechanism between the first operating rod 72 and the operating lever 16 is disengaged and the operating lever 16 becomes inoperable. When the operating button 16a is pressed, the link mechanism is reconnected and the operating lever becomes operable.

[0062] Referring to Figure 7, the operation of the operating lever 16 will be explained. In Figure 7, the circles A through F indicate the main positions of the operating lever 16 in the insertion hole 70a. In position A, the accelerator 12b is unloaded, and no fuel is supplied to the engine 12. Therefore, the engine 12 does not start and remains stopped. Also, the switching valve 15 is in the closed position, and the connection between the second oil supply pipe 62 and the return oil pipe 63 and the pair of oil supply pipes 64, 64 is blocked, so no hydraulic fluid is supplied to the hydraulic motor 10. Therefore, the hydraulic motor 10 does not drive, and the drum 2 does not rotate.

[0063] By swinging the operating lever 16 in the vertical direction of Y1 to position B, the first operating rod 72 slides, and the accelerator 12b is displaced by a predetermined amount. This allows fuel to be supplied to the engine 12, making it possible to start the engine 12. In this state, when the engine 12 key is operated to energize the engine 12 and activate the starter motor, the engine 12 starts.

[0064] Since the switching valve 15 is in the closed position, the hydraulic motor 10 does not receive pressurized oil and therefore does not operate. When the pressurized oil reaches a predetermined pressure, the hydraulic pump 14 stops discharging.

[0065] When the operating lever 16 is swung laterally in the direction of C and D of Y2, the switching lever 15a swings via the first operating rod 72 and the second operating rod 73, and the switching valve 15 switches to the forward flow position. As a result, hydraulic fluid is supplied to the hydraulic motor 10, and the drum 2 begins to rotate in the forward direction.

[0066] When the operating lever 16 is swung vertically in the direction of Y1 to position C, the displacement of the accelerator 12b decreases, and the output of the engine 12 decreases. Consequently, the discharge volume of the hydraulic pump 14 decreases, and the flow rate of pressurized oil supplied to the hydraulic motor 10 decreases, so the rotational speed of the drum 2 decreases. When the operating lever 16 is swung in the opposite direction of Y1 to position D, the displacement of the accelerator 12b increases, and the output of the engine 12 increases. Consequently, the discharge volume of the hydraulic pump 14 increases, and the flow rate of pressurized oil supplied to the hydraulic motor 10 increases, so the rotational speed of the drum 2 increases.

[0067] On the other hand, by swinging the operating lever 16 in the lateral direction where E and F of Y2 are located, the switching valve 15 is switched to the reverse flow position. As a result, hydraulic fluid is supplied to the hydraulic motor 10 in the reverse direction, and the drum 2 rotates in the reverse direction.

[0068] When the operating lever 16 is swung vertically in the direction of Y1 to position E, the displacement of the accelerator 12b decreases, and the output of the engine 12 decreases. Consequently, the discharge volume of the hydraulic pump 14 decreases, and the flow rate of pressurized oil supplied to the hydraulic motor 10 decreases, so the rotational speed of the drum 2 decreases. When the operating lever 16 is swung in the opposite direction of Y1 to position F, the displacement of the accelerator 12b increases, and the output of the engine 12 increases. Consequently, the discharge volume of the hydraulic pump 14 increases, and the flow rate of pressurized oil supplied to the hydraulic motor 10 increases, so the rotational speed of the drum 2 increases.

[0069] In other words, in this mixer unit 1, the flow path of the pressurized oil supplied to the hydraulic motor 10 is changed by operating the operating lever 16 horizontally to switch the switching valve 15, thereby reversing the rotation direction of the drum 2. Then, by operating the operating lever 16 vertically to displace the accelerator 12b, the flow rate of the pressurized oil supplied to the hydraulic motor 10 is adjusted, thereby changing the rotation speed of the drum 2 to high or low.

[0070] To stop the operation of the mixer unit 1, return the operating lever 16 to position A. This will put the engine 12 into an idling state. In this state, operate the engine key to stop the engine 12.

[0071] The switching valve 15 only switches the flow path of the hydraulic fluid, so a general-purpose valve can be used and is readily available. The rotation speed of the drum 2 is changed by a single hydraulic pump 14, so the structure can be simplified and implemented at low cost. Consequently, the mixer unit 1 can also be made lighter. The operating lever is also easy to use, as it is operated horizontally when the drum is reversed and vertically when the drum's rotation speed is changed.

[0072] (Improvements to the washing facilities) After using mixer unit 1, it is necessary to immediately wash it with water to remove any fresh concrete adhering to drum 2, outlet chute 4, etc. Therefore, a relatively large amount of washing water is required on site, but in the case of such mixer unit 1, the installation space is limited and the load capacity is also restricted.

[0073] In contrast, conventional mixer unit 1 uses the frame 50 as a water tank. However, in this case, the frame 50 is prone to corrosion, which is disadvantageous in terms of strength and durability. Draining the water is also difficult, and the inside of the frame 50 remains constantly wet, which accelerates corrosion. Therefore, this mixer unit 1 is designed to eliminate these problems.

[0074] In other words, this mixer unit 1 is provided with a water tank 30 for storing washing water, separate from the frame 50. A large amount of washing water is required for washing. For example, it is preferable to be able to use about 100 liters of washing water.

[0075] Therefore, the water tank 30 is large, but it is difficult to install in the mixer unit 1, which has limited installation space. In contrast, this mixer unit 1 makes effective use of the space at the rear lower part of the forward-tilting drum 2, and installs the large water tank 30, which is provided separately from the frame 50, in a well-balanced manner.

[0076] As shown in Figures 1 to 4, a horizontally elongated, box-shaped water tank 30 is installed independently of the frame 50 in the space below the drum 2 at the rear of the frame 50, more specifically, in the space between the pair of support columns 53a, 53a in the support frame section 53 and below the lower beam 53c. Unlike the frame 50, the water tank 30 is made of stainless steel, making it lightweight and rust-resistant. Furthermore, the water tank 30 is detachable from the frame 50.

[0077] The water tank 30 has a length approximately the same as the distance between the left and right frames of the outer frame 51 and is positioned to fit between the left and right support columns 53a, 53a. By positioning the water tank 30 in this manner across approximately the entire left-right area of ​​the frame 50, a stable balance of weight in the left-right direction can be ensured even when a large amount of water is stored inside.

[0078] Furthermore, by positioning the water tank 30 at the rear of the frame 50, the weight balance in the front-to-rear direction is improved in relation to the drive system equipment, which is concentrated at the front of the frame 50. Therefore, even when transporting a mixer unit 1 loaded near the maximum load capacity of a small truck, the weight balance is less unbalanced, allowing for relatively stable operation. Loading and unloading the mixer unit 1 is also easy.

[0079] The upper part of the water tank 30 has an inclined surface 30a that faces the outer circumferential surface of the rear of the drum 2. As shown in Figure 1, a water inlet 30b is provided on the right side of the inclined surface 30a. By providing such an inclined surface 30a on the water tank 30, the lower part of the water tank 30 can be made to bulge out below the drum 2, promoting a larger capacity for the water tank 30. As a result, this water tank 30 achieves a capacity of approximately 100L. This can be achieved within the weight limit due to the weight reduction of the drive system equipment.

[0080] As shown in Figures 1, 2, and 3, the water pump 31 is installed close to the right front side of the water tank 30. The water pump 31 is powered by electricity supplied from the battery 13 (the battery 13 is shared with the engine 12). Figure 8 shows the washing equipment provided by this mixer unit 1. The water tank 30 has a drain port 30c and a water inlet 30d at its bottom. The drain port 30c can be opened and closed manually.

[0081] The water inlet 30d is connected to the water inlet 31a of the water pump 31 via the upstream water supply path 32. The upstream water supply path 32 is equipped with an on-off valve 33 that can be manually opened and closed. Normally, the on-off valve 33 is set to the open position. The discharge port 31b of the water pump 31 is connected to the cleaning nozzle 35 via the downstream water supply path 34.

[0082] The cleaning nozzle 35 is configured so that when the lever is pushed in, the nozzle opens and cleaning water is sprayed out. The downstream side of the downstream water supply path 34 consists of a long hose 34a. A drain valve 36 is installed at the upstream end of the downstream water supply path 34, located below the water pump 31.

[0083] During the coldest part of winter, the cleaning water in the water pump 31 may freeze. If a large amount of cleaning water is stored in the water tank 30, high water pressure is applied to the water pump 31, making it easy for the water pump 31 to become completely filled with cleaning water. If the cleaning water in the water pump 31 freezes under these conditions, the water pump 31 may be damaged.

[0084] In contrast, this mixer unit 1 allows for the draining of water from the water pump 31, thus avoiding such problems. Specifically, the on / off valve 33 is closed. Then, the drain valve 36 is operated to allow water to drain. With the unit in this state, the cleaning nozzle 35 is operated, and by opening the nozzle, the cleaning water inside the water pump 31 can be discharged.

[0085] The disclosed technology is not limited to the embodiments described above, but also includes various other configurations. For example, the drain valve 36 may be integrated with the water pump 31. [Explanation of Symbols]

[0086] 1 Mixer Unit 2 drums 10 Hydraulic motor 11. Hydraulic oil tank 12 Engines 12a Output shaft 13 batteries 14. Hydraulic pump (piston pump) 15. Switching valve 16. Operating levers 17 Plummer Blocks 18 Ring Chain 30 water tanks 31 Water pump 50 frames 54 Guide rollers

Claims

1. A mixer unit that can be loaded onto the cargo bed of a small truck with a load capacity of less than 2 tons and transported, A frame smaller than the area of ​​the aforementioned cargo bed, A drum is supported in a forward-tilted state by a support base provided on the front part of the frame and a support frame provided on the rear part of the frame, and rotates in the forward direction to agitate the contained ready-mix concrete and rotates in the reverse direction to discharge the ready-mix concrete, A hydraulic motor rotates the drum, A piston pump that supplies pressurized oil to the aforementioned hydraulic motor, One engine drives the aforementioned piston pump, A manual switching valve is installed in the hydraulic circuit between the piston pump and the hydraulic motor, and the flow path of the pressurized oil supplied to the hydraulic motor is switched by the swinging of a switching lever. An operating mechanism for operating the engine and the switching valve, Equipped with, The hydraulic motor, the piston pump, the engine, and the switching valve are installed together on the support base, and the operating mechanism is installed along the edge of the frame. The aforementioned operating mechanism is An operating lever that can swing vertically and horizontally, A first operating rod connected to the aforementioned operating lever and the accelerator of the engine, A second operating rod is connected perpendicularly to the first operating rod and also connected to the switching lever, It has, A mixer unit in which, when the operating lever is swung laterally, the switching lever swings via the first operating rod and the second operating rod, thereby switching the switching valve and reversing the rotation direction of the drum, and when the operating lever is swung vertically, the first operating rod slides, displacing the accelerator of the engine, which increases or decreases the flow rate of pressurized oil supplied to the hydraulic motor, causing the rotation speed of the drum to change between high and low.

2. In the mixer unit according to claim 1, Equipped with a water tank to hold cleaning water, A mixer unit in which the water tank is provided on the frame in a manner independent of the frame.

3. In the mixer unit according to claim 2, A water pump connected to the water tank via an upstream water supply path, The water pump and the cleaning nozzle connected via the downstream water supply path, Furthermore, A mixer unit in which an on / off valve is installed in the upstream water supply path, and a drain valve is installed in the portion between the water pump and the upstream end of the downstream water supply path.

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