Working machine

Abstract

To provide a technique where stop state of a work machine is kept even when a clutch mechanism is switched from a transmission state into a non-transmission state.SOLUTION: A work machine comprises: a first grounding part; a drive part which drives the first grounding part; a clutch mechanism which is in a state switchable between a transmission state where drive force of the drive part is transmitted to the first grounding part and a non-transmission state where the drive force is not transmitted to the grounding part; a clutch operation part; a brake mechanism which is in a state switchable between a braking state where the first grounding part is braked and a non-braking state where the first grounding part is not braked; and a braking operation part. When the braking mechanism is in the braking state, the clutch mechanism can be switched from the transmission state into the non-transmission state by operating the clutch operation part. When the braking mechanism is in the non-braking state, the clutch mechanism cannot be switched from the transmission state into the non-transmission state even though by operating the clutch operation part.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The technology disclosed in this specification relates to a working machine.

Background Art

[0002] Patent Document 1 discloses a working machine including a grounding portion that grounds to the ground, a driving portion that drives the grounding portion, a transmission state in which the driving force from the driving portion is transmitted to the grounding portion, a non-transmission state in which the driving force is not transmitted to the grounding portion, a clutch mechanism that can be switched to any one of the states, a clutch operation portion for switching the state of the clutch mechanism, a braking state in which the grounding portion is being braked, a non-braking state in which the grounding portion is not being braked, a braking mechanism that can be switched to any one of the states, and a braking operation portion for switching the state of the braking mechanism. In this working machine, when the state of the braking mechanism is the non-braking state, the state of the clutch mechanism can be switched from the transmission state to the non-transmission state.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, there may be a situation where it is desired to stop the working machine on a slope. In such a situation, even if the state of the braking mechanism is the non-braking state, if the state of the clutch mechanism is the transmission state, since the driving portion is stopped, the working machine will stop on the slope. However, when the state of the braking mechanism is the non-braking state, if the state of the clutch mechanism is switched from the transmission state to the non-transmission state, there is a risk that the working machine may move on the slope unintentionally even if the driving portion is stopped.

[0005] This specification provides a technique that can maintain the working machine in a stopped state even when the state of the clutch mechanism is switched from the transmission state to the non - transmission state.

Means for Solving the Problems

[0006] The working machine disclosed in this specification includes a first grounding part that grounds to the ground, a driving part that drives the first grounding part, a transmission state in which the driving force from the driving part is transmitted to the first grounding part, and a non - transmission state in which the driving force is not transmitted to the grounding part. It may further include a clutch mechanism that can be switched to either state, a clutch operation part for switching the state of the clutch mechanism, a braking state in which the first grounding part is being braked, and a non - braking state in which the first grounding part is not being braked. It may also include a braking mechanism that can be switched to either state and a braking operation part for switching the state of the braking mechanism. When the state of the braking mechanism is the braking state, by operating the clutch operation part, the state of the clutch mechanism can be switched from the transmission state to the non - transmission state. When the state of the braking mechanism is the non - braking state, even if the clutch operation part is operated, the state of the clutch mechanism may not be able to be switched from the transmission state to the non - transmission state.

[0007] According to the above configuration, only when the state of the braking mechanism is the braking state can the state of the clutch mechanism be switched from the transmission state to the non - transmission state. When the state of the braking mechanism is the non - braking state, the state of the clutch mechanism cannot be switched from the transmission state to the non - transmission state. Therefore, when the state of the clutch mechanism is switched from the transmission state to the non - transmission state, the driving part is braked by the braking mechanism. Thus, even when the state of the clutch mechanism is switched from the transmission state to the non - transmission state, the working machine can be maintained in a stopped state.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

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Figure 21

Embodiments for Carrying Out the Invention

[0009] Hereinafter, representative and non-limiting specific examples of the present invention will be described in detail with reference to the drawings. This detailed description is merely intended to show those skilled in the art the details for implementing preferred examples of the present invention, and is not intended to limit the scope of the present invention. Also, the additional features and inventions disclosed below can be used separately or together with other features and inventions in order to provide further improved working machines, their manufacturing methods, and usage methods.

[0010] Also, the combinations of features and steps disclosed in the following detailed description are not essential for carrying out the invention in the broadest sense, and are described only for the purpose of explaining representative specific examples of the invention in particular. Further, the various features of the above and below representative specific examples, as well as the various features described in the independent and dependent claims, need not be combined as described in the specific examples herein or in the order listed, in providing additional and useful embodiments of the invention.

[0011] All features described in this specification and / or the claims are intended to be disclosed separately and independently of each other, as limitations to the initial disclosure and the claimed specific matters, apart from the configurations of the features described in the embodiments and / or claims. Further, all descriptions regarding numerical ranges and groups or populations are made with the intention of disclosing intermediate configurations as limitations to the initial disclosure and the claimed specific matters.

[0012] In one or more embodiments, the working machine may include a first grounding portion that contacts the ground, a driving portion that drives the first grounding portion, a transmission state in which the driving force from the driving portion is transmitted to the first grounding portion, a non-transmission state in which the driving force is not transmitted to the grounding portion, a clutch mechanism that can be switched to any of these states, a clutch operation portion for switching the state of the clutch mechanism, a braking state in which the first grounding portion is being braked, a non-braking state in which the first grounding portion is not being braked, a braking mechanism that can be switched to any of these states, and a braking operation portion for switching the state of the braking mechanism. When the state of the braking mechanism is the braking state, the state of the clutch mechanism can be switched from the transmission state to the non-transmission state by operating the clutch operation portion. When the state of the braking mechanism is the non-braking state, it may not be possible to switch the state of the clutch mechanism from the transmission state to the non-transmission state even if the clutch operation portion is operated.

[0013] In one or more embodiments, the clutch operation unit may switch the state of the clutch mechanism from the transmission state to the non - transmission state according to a user's operation.

[0014] For example, when the clutch operation unit is configured to use electric power to switch the clutch mechanism from the transmission state to the non - transmission state, if an abnormality occurs in the power system related to the clutch operation unit, the state of the clutch mechanism cannot be switched from the transmission state to the non - transmission state. According to the above configuration, even if an abnormality occurs in a part of the power system related to the clutch operation unit, the user can manually operate the clutch operation unit to switch the state of the clutch mechanism from the transmission state to the non - transmission state. Therefore, the convenience of the user can be improved.

[0015] In one or more embodiments, the clutch operation unit may include a clutch operation lever operable by the user. According to the user's operation on the clutch operation lever, the state of the clutch mechanism may be switched from the non - transmission state to the transmission state.

[0016] According to the above configuration, the configuration for operating the clutch mechanism can be simplified.

[0017] In one or more embodiments, the braking operation unit may switch the state of the braking mechanism from the non - braking state to the braking state according to the user's operation.

[0018] For example, in the case where the braking operation unit is configured to switch the braking mechanism from the non-braking state to the braking state using electric power, if an abnormality occurs in the power system related to the braking operation unit, it becomes impossible to switch the state of the braking mechanism from the non-braking state to the braking state. As a result, it becomes impossible to switch the state of the clutch mechanism from the transmission state to the non-transmission state. According to the above configuration, even when an abnormality occurs in the power system related to the braking operation unit, the user can switch the state of the braking mechanism from the non-braking state to the braking state, and as a result, can switch the state of the clutch mechanism from the transmission state to the non-transmission state. Therefore, the convenience for the user can be improved.

[0019] In one or more embodiments, the braking operation unit may include a braking operation lever operable by the user. The state of the braking mechanism may be switched from the non-braking state to the braking state in response to the user's operation on the braking operation lever.

[0020] According to the above configuration, the configuration for operating the braking mechanism can be simplified.

[0021] In one or more embodiments, the work machine may further include a gripping portion grippable by the user. When the user is gripping the gripping portion and the clutch mechanism is in the non-transmission state, the clutch operation unit is arranged at a position where at least a part of the clutch operation unit is visible to the user. When the user is gripping the gripping portion and the clutch mechanism is in the transmission state, the clutch operation unit may be arranged at a position where the user cannot visually recognize the clutch operation unit.

[0022] According to the above configuration, the user can grasp the state of the clutch mechanism according to whether at least a part of the clutch operation unit is visible. Therefore, the convenience for the user can be improved.

[0023] In one or more embodiments, the working machine may further include a second grounding portion provided in front of or behind the first grounding portion and grounding to the ground. When the clutch mechanism is in the non-transmission state, at least a part of the clutch operation portion may be disposed between the first grounding portion and the second grounding portion.

[0024] According to the above configuration, since at least a part of the clutch operation portion is provided between the first grounding portion and the second grounding portion, the user can easily visually recognize at least a part of the clutch operation portion.

[0025] In one or more embodiments, the working machine may further include a support frame. When the clutch mechanism is in the non-transmission state, at least a part of the clutch operation portion may be disposed outside the support frame when the working machine is viewed from above.

[0026] According to the above configuration, since at least a part of the clutch operation portion is provided outside the support frame, the user can easily visually recognize at least a part of the clutch operation portion.

[0027] In one or more embodiments, the working machine may be a carrier vehicle.

[0028] The carrier vehicle is used to carry heavy objects (for example, a large amount of sand, etc.). For this reason, it is desirable that the stopped state of the carrier vehicle is maintained even when the clutch mechanism of the carrier vehicle stopped on a slope is switched from the transmission state to the non-transmission state. According to the above configuration, even when the state of the clutch mechanism is switched from the transmission state to the non-transmission state, the stopped state of the carrier vehicle can be maintained.

[0029] (Example) Referring to FIGS. 1 to 21, the carrier 2 will be described. The carrier 2 is a hand-pushed type carrier. As shown in FIG. 1, the carrier 2 includes a chassis unit 4 and a loading platform unit 6. The loading platform unit 6 includes a bucket 500 and a loading platform frame 502 extending in the front-rear direction. In the loading platform unit 6, the loading platform frame 502 is fixed to the chassis unit 4 by screwing. Also, in the loading platform unit 6, the bucket 500 is not fixed to the loading platform frame 502, and the user can place the bucket 500 on the loading platform frame 502 or lift the bucket 500 and remove it from the loading platform frame 502. The user can load soil, fertilizer, etc. into the bucket 500 and transport it.

[0030] (Configuration of the chassis unit 4) As shown in FIG. 2, the chassis unit 4 includes a handle unit 10, a battery box 12, a chassis frame 14, a front wheel unit 16, and a rear wheel unit 18.

[0031] (Configuration of the battery box 12) The battery box 12 is fixed to the handle unit 10. The battery box 12 houses a battery pack 12a (see FIG. 3) and a control device 12b (see FIG. 3). The control device 12b (see FIG. 3) controls the operation of a motor 170 (see FIG. 3) described later. The battery box 12 is provided with a remaining amount display unit (not shown) for displaying the remaining amount of the battery pack 12a (see FIG. 3), etc.

[0032] (Configuration of the handle unit 10) The handle unit 10 includes a handle base 20, a right handle 22, and a left handle 24. The right handle 22 and the left handle 24 are screwed to the handle base 20. The handle base 20 is screwed to a frame plate 150 of the chassis frame 14 described later. The battery box 12 is screwed to the handle base 20.

[0033] The right handle 22 includes a right pipe 30, a right grip 32, a switch box 34, and a drive lever 36. The right pipe 30 includes a right support portion 30a extending in the vertical direction and a right handle portion 30b bent rearward from the upper end of the right support portion 30a. The right grip 32 and the switch box 34 are attached to the right handle portion 30b of the right pipe 30. The right grip 32 is provided behind the switch box 34.

[0034] The switch box 34 includes a right casing 38 and an operation panel 40. The operation panel 40 is provided on the upper surface of the right casing 38. The operation panel 40 is provided with a main power switch 40a, a forward / backward changeover switch 40b, a speed changeover switch 40c, etc. The drive lever 36 is attached to the rear portion of the right casing 38. Inside the switch box 34, a drive switch 42 (see FIG. 3) for detecting that the drive lever 36 has been pulled up is accommodated. As shown in FIG. 3, the main power switch 40a, the forward / backward changeover switch 40b, the speed changeover switch 40c, and the drive switch 42 are connected to a control device 12b in a battery box 12 (see FIG. 2). When the control device 12b receives a signal indicating that the drive lever 36 (see FIG. 2) has been pulled up, it drives a motor 170 described later.

[0035] As shown in FIG. 2, the left handle 24 includes a left pipe 50, a left grip 52, a left casing 54, and a brake operation mechanism 56. The left pipe 50 includes a left support portion 50a extending in the vertical direction and a left handle portion 50b bent rearward from the upper end of the left support portion 50a. As shown in FIG. 4, the left grip 52 and the left casing 54 are attached to the left handle portion 50b of the left pipe 50. The left grip 52 is provided behind the left casing 54.

[0036] The brake operating mechanism 56 includes a brake lever 58, a first link member 60, a cable holding portion 62, and a fixing lever 64. The brake lever 58 includes an operating portion 66, a support portion 68, and a bearing holding portion 70. The operating portion 66, the support portion 68, and the bearing holding portion 70 are integrally formed. The support portion 68 and the bearing holding portion 70 are housed inside the left casing 54. The operating portion 66 protrudes from the inside of the left casing 54 to the outside through an opening 54a formed in the rear surface of the left casing 54. The support portion 68 is rotatably supported around a rotation axis 72 extending in the left-right direction with respect to the left casing 54. As shown in FIG. 5, a recess 66a recessed upward is provided on the lower surface of the front portion of the operating portion 66. A first protrusion 66b protruding downward and a second protrusion 66c protruding downward are provided at the front portion of the recess 66a. The lower end of the second protrusion 66c is located below the lower end of the first protrusion 66b. A left spring receiving portion 68a is provided on the left side of the support portion 68. As shown in FIG. 6, a right spring receiving portion 68b is provided on the right side of the support portion 68. A torsion spring 74 is provided on the left spring receiving portion 68a and the right spring receiving portion 68b. Due to the biasing force of the torsion spring 74, the brake lever 58 is biased with respect to the left casing 54 such that the rear portion of the brake lever 58 faces downward. The bearing holding portion 70 is connected to the front portion of the support portion 68. The bearing holding portion 70 includes a right wall portion 70a, a left wall portion 70b (see FIG. 5), and a shaft 70c. The shaft 70c extends in the left-right direction and communicates the right wall portion 70a and the left wall portion 70b. The brake lever 58 further includes a bearing 76. The bearing 76 is attached to the shaft 70c between the right wall portion 70a and the left wall portion 70b.

[0037] As shown in FIG. 4, the first link member 60 includes a support portion 80, a first extension portion 82 extending forward and upward from the support portion 80, and a second extension portion 84 extending rearward and upward from the support portion 80. The support portion 80 is supported so as to be rotatable about a rotation axis 86 extending in the left - right direction with respect to the left - side casing 54. A bearing 76 is in contact with the upper surface 84a of the second extension portion 84. In the first extension portion 82, a through - hole 82a penetrating the first extension portion 82 in the left - right direction is provided at an end on the side opposite to the support portion 80 side.

[0038] As shown in FIG. 5, the cable holding portion 62 includes a right wall portion 90, a left wall portion 92, a front wall portion 94, and a shaft 96. The right wall portion 90, the left wall portion 92, and the front wall portion 94 are integrally formed. The shaft 96 extends in the left - right direction, passes through the through - hole 82a (see FIG. 4) of the first link member 60, and connects the right wall portion 90 and the left wall portion 92. The first link member 60 and the cable holding portion 62 are rotatably connected by the shaft 96. A notch portion 94a extending leftward from the right end of the front wall portion 94 is provided in the front wall portion 94. As shown in FIG. 4, a brake cable 100 is connected to the cable holding portion 62. The brake cable 100 includes an inner cable 100a and an outer cable 100b covering the periphery of the inner cable 100a. The inner cable 100a passes through the notch portion 94a, and the end portion of the inner cable 100a is held by the cable holding portion 62. The end portion of the outer cable 100b is held by the left - side casing 54.

[0039] As shown in FIG. 7, when the user pulls up the operation portion 66 of the brake lever 58, the bearing holding portion 70 of the brake lever 58 moves downward. When the bearing holding portion 70 moves downward, the second extension portion 84 of the first link member 60 moves downward and the first extension portion 82 of the first link member 60 moves rearward. When the first extension portion 82 of the first link member 60 moves rearward, the cable holding portion 62 moves rearward. When the cable holding portion 62 moves rearward, the inner cable 100a of the brake cable 100 is relatively pulled out (i.e., moves to the rear side) with respect to the outer cable 100b.

[0040] As shown in FIG. 4, when the user releases the hand from the operation portion 66 of the brake lever 58, the operation portion 66 of the brake lever 58 is pushed down by the biasing force of the torsion spring 74, and the bearing holding portion 70 of the brake lever 58 moves upward. When the bearing holding portion 70 moves upward, the second extension portion 84 of the first link member 60 moves upward and the first extension portion 82 of the first link member 60 moves forward. When the first extension portion 82 of the first link member 60 moves forward, the cable holding portion 62 moves forward. When the cable holding portion 62 moves forward, the inner cable 100a of the brake cable 100 is relatively pushed in (i.e., moves to the front side) with respect to the outer cable 100b.

[0041] As shown in FIG. 5, the fixing lever 64 includes an operation portion 110, a support portion 112, a protrusion portion 114, and a spring receiving portion 116 (see FIG. 6). As shown in FIG. 4, the fixing lever 64 is provided below the brake lever 58. The operation portion 110 protrudes from the inside to the outside of the left casing 54 through an opening 54a formed in the rear surface of the left casing 54. The support portion 112 is rotatably supported with respect to the left casing 54 around a rotation shaft 118 extending in the left-right direction. As shown in FIG. 5, the protrusion portion 114 protrudes upward from the support portion 112. The upper portion of the protrusion portion 114 is in contact with the recess 66a of the brake lever 58. As shown in FIG. 6, the spring receiving portion 116 is provided on the right side of the support portion 112. A torsion spring 120 is provided on the spring receiving portion 116. By the biasing force of the torsion spring 120, the fixing lever 64 is biased with respect to the left casing 54 such that the rear portion of the fixing lever 64 faces downward.

[0042] As shown in FIG. 5, when the brake lever 58 is not operated by the user, the upper portion of the protrusion portion 114 of the fixing lever 64 is in contact with the recess 66a of the brake lever 58. In this state, when the user attempts to pull up the fixing lever 64, the front surface of the protrusion portion 114 of the fixing lever 64 contacts the rear surface of the first protrusion portion 66b of the brake lever 58, so that the fixing lever 64 cannot be pulled up. Further, after the user pulls up the operation portion 66 of the brake lever 58 and then releases the hand from the brake lever 58, the rear portion of the operation portion 66 of the brake lever 58 is pushed down with respect to the left casing 54 by the biasing force of the torsion spring 74.

[0043] As shown in FIG. 8, when the user pulls up the operation portion 66 of the brake lever 58 and further pulls up the operation portion 110 of the fixing lever 64, the protrusion 114 of the fixing lever 64 moves forward of the recess 66a of the brake lever 58 and the protrusion 114 comes into contact with the lower surface of the first protrusion 66b of the operation portion 66. In this state, the protrusion 114 of the fixing lever 64 is biased rearward and upward with respect to the left casing 54 by the biasing force of the torsion spring 120. On the other hand, the portion of the brake lever 58 that is in contact with the protrusion 114 of the fixing lever 64 is biased rearward and downward with respect to the left casing 54 by the biasing force of the torsion spring 74. However, due to the interference between the protrusion 114 of the fixing lever 64 and the portion of the brake lever 58 that is in contact with the protrusion 114 of the fixing lever 64, the rotation of the fixing lever 64 and the brake lever 58 with respect to the left casing 54 is prohibited. Thus, the brake lever 58 is fixed in the pulled-up state by the fixing lever 64. In this state, when the user further pulls up the operation portion 66 of the brake lever 58, the rear portion of the fixing lever 64 moves downward and the protrusion 114 moves rearward by the biasing force of the torsion spring 120. Thereby, the fixing of the brake lever 58 by the fixing lever 64 is released. Then, when the user releases the hand from the operation portion 66 of the brake lever 58, the rear portion of the operation portion 66 of the brake lever 58 is pushed down with respect to the left casing 54 by the biasing force of the torsion spring 74.

[0044] As shown in Fig. 4, the left casing 54 further houses a stop switch 130 and a second link member 132. One end 132a of the second link member 132 is connected to the stop switch 130, and the other end 132b of the second link member 132 is provided near the second protrusion 66c of the brake lever 58. The other end 132b of the second link member 132 is biased in a direction away from the stop switch 130 by a spring (not shown). In a state where the brake lever 58 is not operated, the switch portion 130a (see Fig. 7) of the stop switch 130 is pressed by the second link member 132. As shown in Fig. 7, when the user pulls up the brake lever 58, the other end 132b of the second link member 132 moves in a direction away from the switch portion 130a of the stop switch 130, causing the second link member 132 to separate from the switch portion 130a of the stop switch 130. Thereby, it is detected that the brake lever 58 has been pulled up. As shown in Fig. 3, the stop switch 130 is connected to the control device 12b in the battery box 12 (see Fig. 2) via a signal cable 134 (see Fig. 4). When the control device 12b receives a signal indicating that the brake lever 58 has been pulled up, it stops the drive of the motor 170, which will be described later.

[0045] (Configuration of the chassis frame 14) As shown in FIG. 2, the vehicle body frame 14 includes a frame plate 150, a right frame pipe 152, a left frame pipe 154, and a center frame pipe 156. The rear wheel unit 18 is attached to the frame plate 150. The rear ends of the right frame pipe 152 and the left frame pipe 154 are welded to the frame plate 150 and extend forward. The distance between the right frame pipe 152 and the left frame pipe 154 widens from the rear to the front. The front wheel unit 16 is attached to the front ends of the right frame pipe 152 and the left frame pipe 154. The center frame pipe 156 is disposed near the front wheel unit 16, with its right end welded to the right frame pipe 152 and its left end welded to the left frame pipe 154. A cable cover 158 for protecting a power supply cable (not shown) connecting the battery box 12 and the right headlamp 176 and the left headlamp 178 (described later) to the right frame pipe 152, and a power cable (not shown) connecting the battery box 12 and the motor 170 (described later) is attached to the right frame pipe 152.

[0046] (Configuration of the rear wheel unit 18) The rear wheel unit 18 includes a base plate 320, a hinge 322, a right rear wheel 324, and a left rear wheel 326. The right rear wheel 324 and the left rear wheel 326 are driven wheels. The right rear wheel 324 is connected to the right end portion of the base plate 320, and the left rear wheel 326 is connected to the left end portion. The hinge 322 is welded to the upper surface of the base plate 320.

[0047] (Configuration of the front wheel unit 16) As shown in FIG. 9, the front wheel unit 16 includes a right front wheel 160, a left front wheel 162, a right front wheel brake 164, a left front wheel brake 166, a brake equalizer 168, a motor 170, an electromagnetic brake case 171, a gearbox 172, a clutch operating mechanism 174, a right headlight 176, and a left headlight 178. A right axle case 180 and a left axle case 182 are screwed and fixed to the gearbox 172. The right front wheel 160 is connected to the gearbox 172 via a right drive shaft 184 (see FIGS. 10 and 11) extending within the right axle case 180. The left front wheel 162 is connected to the gearbox 172 via a left drive shaft 186 (see FIGS. 10 and 11) extending within the left axle case 182. The right axle case 180 is held by the right frame pipe 152 via a right bracket 188 welded to the right frame pipe 152. The left axle case 182 is held by the left frame pipe 154 via a left bracket 190 welded to the left frame pipe 154. As shown in FIG. 10, the right drive shaft 184 extends in the left - right direction within the right axle case 180 and is rotatably supported by the right axle case 180. The left drive shaft 186 extends in the left - right direction within the left axle case 182 and is rotatably supported by the left axle case 182.

[0048] As shown in FIG. 9, the right front wheel brake 164 includes a disk rotor 192 and a brake caliper 194. The disk rotor 192 is disposed on the left side of the right front wheel 160 and is fixed to the right front wheel 160 via a hub 160a. The brake caliper 194 is disposed corresponding to the disk rotor 192. The brake caliper 194 is held by the right bracket 188. A right brake cable 196 is connected to the brake caliper 194. The right brake cable 196 includes an inner cable 196a and an outer cable 196b that covers the periphery of the inner cable 196a. When the inner cable 196a of the right brake cable 196 is relatively drawn into the outer cable 196b, the brake caliper 194 clamps the vicinity of the outer edge of the disk rotor 192 by a pair of brake pads (not shown), thereby applying a frictional force to the disk rotor 192 to brake the right front wheel 160. When the inner cable 196a of the right brake cable 196 is relatively pushed out of the outer cable 196b, the pair of brake pads are separated from the disk rotor 192, and the brake of the right front wheel 160 is released. The right front wheel brake 164 may be a so-called disk brake as described above, or may be another type of brake, such as a drum brake or a band brake.

[0049] The left front wheel brake 166 includes a disc rotor 198 and a brake caliper 200. The disc rotor 198 is disposed on the right side of the left front wheel 162 and is fixed to the left front wheel 162 via a hub 162a. The brake caliper 200 is disposed corresponding to the disc rotor 198. The brake caliper 200 is held by a left bracket 190. A left brake cable 202 is connected to the brake caliper 200. The left brake cable 202 includes an inner cable 202a and an outer cable 202b that covers the periphery of the inner cable 202a. When the inner cable 202a of the left brake cable 202 is relatively drawn into the outer cable 202b, the brake caliper 200 clamps the vicinity of the outer edge of the disc rotor 198 with a pair of brake pads (not shown), thereby applying a frictional force to the disc rotor 198 to apply a brake to the left front wheel 162. When the inner cable 202a of the left brake cable 202 is relatively pushed out of the outer cable 202b, the pair of brake pads separate from the disc rotor 198, and the brake on the left front wheel 162 is released. The left front wheel brake 166 may be a so-called disc brake as described above, or may be another type of brake, such as a drum brake or a band brake.

[0050] (Brake equalizer 168) The brake equalizer 168 includes a support plate 210, a rotating plate 212, a first link member 214, and a second link member 216. The central frame pipe 156 passes through between the support plate 210 and the rotating plate 212.

[0051] The support plate 210 is fixed to the motor 170 via the bracket 218. As shown in FIG. 12, the support plate 210 includes a base portion 220, a right extension portion 222 extending downward from the right end of the front portion of the base portion 220, and a left extension portion 224 extending downward from the left end of the front portion of the base portion 220. Openings 220a and 220b are provided on both the left and right sides of the rear portion of the base portion 220. The first link member 214 and the second link member 216 are rotatably held by the support plate 210 via a rotation shaft 226 extending in the vertical direction. The first link member 214 includes an input arm 214a extending forward from the rotation shaft 226 and an output arm 214b extending right rearward from the rotation shaft 226. An inner cable 100a of a brake cable 100 extending from the brake operation mechanism 56 of the left handle 24 is connected to the tip of the input arm 214a. An inner cable 196a (see FIG. 13) of a right brake cable 196 is connected to the tip of the output arm 214b. The second link member 216 includes an input arm 216a extending right forward from the rotation shaft 226 and an output arm 216b extending left rearward from the rotation shaft 226. An outer cable 100b of the brake cable 100 extending from the brake operation mechanism 56 of the left handle 24 is connected to the tip of the input arm 216a. An inner cable 202a (see FIG. 13) of a left brake cable 202 is connected to the tip of the output arm 216b. The outer cable 196b of the right brake cable 196 and the outer cable 202b of the left brake cable 202 are both fixed to the support plate 210.

[0052] As shown in FIG. 4, when the brake lever 58 of the left handle 24 is not pulled up, as shown in FIG. 12, by the first link member 214, the inner cable 196a of the right brake cable 196 is pushed relatively into the outer cable 196b, and by the second link member 216, the inner cable 202a of the left brake cable 202 is pushed relatively into the outer cable 202b. In this state, the right front wheel 160 and the left front wheel 162 are not braked. Hereinafter, the state where the brakes of the right front wheel 160 and the left front wheel 162 are released may be described as a "non-braking state".

[0053] As shown in FIG. 7, when the brake lever 58 of the left handle 24 is pulled up by the user, the inner cable 100a of the brake cable 100 is pulled relatively into the outer cable 100b. As a result, as shown in FIG. 13, the first link member 214 rotates in a direction in which the input arm 214a moves rightward, and the output arm 214b moves leftward, so that the inner cable 196a of the right brake cable 196 is pulled out relatively from the outer cable 196b. At the same time, the second link member 216 rotates in a direction in which the input arm 216a moves leftward, and the output arm 216b moves rightward, so that the inner cable 202a of the left brake cable 202 is pulled out relatively from the outer cable 202b. As a result, brakes are applied to the right front wheel 160 and the left front wheel 162, respectively. Hereinafter, the state where brakes are applied to the right front wheel 160 and the left front wheel 162, respectively, may be described as a "braking state".

[0054] As shown in FIG. 14, the rotating plate 212 includes an upper wall portion 230, a right wall portion 232 (see FIG. 15), a left wall portion 234, a rear wall portion 236, and an extension portion 238. The upper wall portion 230, the right wall portion 232, the left wall portion 234, the rear wall portion 236, and the extension portion 238 are integrally formed. The rotating plate 212 is rotatably supported around a rotating shaft 239 extending in the left - right direction with respect to the support plate 210. The upper wall portion 230 is inclined so as to go downward from above as it goes forward from the rear. On both left and right sides of the rear part of the upper wall portion 230, protruding portions 230a, 230b protruding upward are provided. The protruding portions 230a, 230b are provided at positions corresponding to the openings 220a, 220b of the support plate 210. A spring receiving portion 230c is provided at the front part of the upper wall portion 230. A spring 230d is provided in the spring receiving portion 230c. By the spring 230d, the front part of the upper wall portion 230 of the rotating plate 212 is urged downward with respect to the support plate 210. The extension portion 238 includes a first extension portion 238a extending leftward from the lower end of the left wall portion 234, and a second extension portion 238b extending forward from the left end of the first extension portion 238a. As shown in FIG. 4, when the brake lever 58 of the left - hand handle 24 is not pulled up, as shown in FIG. 12, the tips of the output arms 214b of the first link member 214 and the tips of the output arms 216b of the second link member 216 are arranged on the upper surfaces of the protruding portions 230a, 230b. And the protruding portions 230a, 230b are pushed downward, that is, into the openings 220a, 220b by the tips of the output arms 214b and the output arms 216b of the second link member 216.

[0055] (Clutch operating mechanism 174) The clutch operating mechanism 174 includes a clutch operating lever 270, a support bracket 272, and a rod operating portion 274. As shown in FIG. 16, the support bracket 272 includes a base portion 280 extending in the front-rear direction, a right extending portion 282 extending rightward from the rear portion of the base portion 280, and a mounting portion 284 extending upward from the right end of the right extending portion 282. The support bracket 272 is screwed and fixed to the gearbox 172 (see FIG. 12) via the mounting portion 284. A through hole 280a through which a rotation shaft 286 (see FIG. 12) penetrates in the vertical direction is provided at the front portion of the base portion 280. A through hole 280b through which a rotation shaft 288 (see FIG. 12) penetrates in the vertical direction is provided at the rear portion of the base portion 280.

[0056] As shown in FIG. 12, the clutch operating lever 270 extends from the left frame pipe 154 to the right front, then curves and extends to the left front. The clutch operating lever 270 is held by the support bracket 272 so as to be rotatable around the rotation shaft 286. Further, the clutch operating lever 270 is connected to the rod operating portion 274 so as to be rotatable around the rotation shaft 290. The clutch operating lever 270 includes a mounting portion 270a for attaching the clutch operating mechanism 174 to the left frame pipe 154. A torsion spring 292 is attached to the rotation shaft 286. The torsion spring 292 is provided between the clutch operating lever 270 and the base portion 280 of the support bracket 272. The function of the torsion spring 292 will be described later.

[0057] As shown in FIG. 14, the rod operation unit 274 includes a cam unit 300, a connecting unit 302, a connecting unit 304 that connects the cam unit 300 and the connecting unit 302, and a protruding unit 306 that protrudes rightward from the right end of the connecting unit 304. The right end of the protruding unit 306 is located further to the right than the right end of the connecting unit 302. The position of the right end of the protruding unit 306 is substantially the same as the position of the right end of the second extension 238b of the rotation plate 212. Also, the height of the protruding unit 306 is substantially the same as the height of the second extension 238b of the rotation plate 212. The cam unit 300 is rotatably held by the support bracket 272 around the rotation axis 288. The cam surface 300a of the cam unit 300 moves the clutch rod 260 (see FIG. 12) described later to the left when the clutch operation lever 270 is attached to the left frame pipe 154 (see FIG. 12), and moves the clutch rod 260 (see FIG. 12) described later to the right when the clutch operation lever 270 is pulled out from the left frame pipe 154 (see FIGS. 17 and 18). The connecting unit 302 is connected to the clutch operation lever 270 so as to be rotatable around the rotation axis 290.

[0058] (Motor 170) As shown in FIG. 10, the motor 170 includes a stator 240, a rotor 242, and a motor case 244. The motor 170 is, for example, a brushless DC motor. The stator 240 and the rotor 242 are housed in the motor case 244. The stator 240 is fixed to the motor case 244. The rotor 242 is fixed to the motor shaft 246. The motor shaft 246 extends in the left - right direction and is rotatably held by the motor case 244. The left end of the motor shaft 246 is connected to the gear box 172. The right end of the motor shaft 246 is connected to the electromagnetic brake case 171. The motor 170 is connected to the battery box 12 (see FIG. 2) via a power cable (not shown). Power is supplied to the motor 170 from the battery pack 12a (see FIG. 3). The operation of the motor 170 is controlled by the control device 12b (see FIG. 3).

[0059] (Electromagnetic brake case 171) The electromagnetic brake case 171 houses an electromagnetic brake 400. The electromagnetic brake 400 includes a key 402, a hub 404, a disk rotor 406, a plate 408, an electromagnet 410, an armature 412, and a spring 414. The key 402 is fitted into a keyway formed at the right end of the motor shaft 246. The disk rotor 406 is fixed to the motor shaft 246 via the key 402 and the hub 404. The electromagnet 410 is provided on the left side of the disk rotor 406. The electromagnet 410 is provided with a spring receiving portion 410a. The spring 414 is provided on the spring receiving portion 410a of the electromagnet 410. The armature 412 is provided between the electromagnet 410 and the disk rotor 406. The spring 414 biases the armature 412 in the right direction (i.e., the disk rotor 406). The plate 408 includes a first plate 408a extending rightward from the rear end portion of the electromagnet 410 and a second plate 408b extending from the right end portion of the first plate 408a toward the motor shaft 246 side. The left surface of the second plate 408b abuts against the right surface of the disk rotor 406. The electromagnetic brake 400 is connected to the battery box 12 (see FIG. 2) via a power cable (not shown). A current is supplied to the electromagnetic brake 400 from the battery pack 12a (see FIG. 3). The operation of the electromagnetic brake 400 is controlled by the control device 12b (see FIG. 3).

[0060] When an electric current is applied to the electromagnet 410, the armchair 412 is attracted to the electromagnet 410 against the biasing force of the spring 414, and the brake on the motor shaft 246 is released. As shown in FIG. 11, when no electric current is applied to the electromagnetic brake 400, the spring 414 biases the armchair 412 in the right direction with respect to the electromagnet 410. In this case, the plate 408 and the armchair 412 sandwich the vicinity of the outer edge of the disc rotor 406, thereby applying a frictional force to the disc rotor 406 to brake the motor shaft 246. In the present embodiment, as shown in FIG. 3, when the control device 12b receives a signal indicating that the drive switch 42 is turned on, the control device 12b drives the motor 170 and applies an electric current to the electromagnet 410 (see FIG. 10). Then, when the control device 12b receives a signal indicating that the stop switch 130 is turned off, the control device 12b drives the motor 170 and stops the application of the electric current to the electromagnet 410 (see FIG. 11).

[0061] (Gearbox 172) As shown in FIG. 11, the gearbox 172 includes a gear case 250, an intermediate shaft 252, a clutch mechanism 256, and a differential mechanism 258. The intermediate shaft 252 extends in the left-right direction and is rotatably held by the gear case 250. The intermediate shaft 252 includes a first gear 253, a second gear 254, and a dog clutch 255. The first gear 253 is fixed to the intermediate shaft 252. The first gear 253 meshes with a spur gear 246a provided on the motor shaft 246. The second gear 254 has an engaging recess 254a recessed in the left direction. The second gear 254 is held non-movable in the left-right direction and rotatably with respect to the intermediate shaft 252. The dog clutch 255 is held movable in the left-right direction and non-rotatably with respect to the second gear 254. The dog clutch 255 protrudes in the left direction and includes an engaging convex portion 255a that can engage with the engaging recess 254a of the second gear 254 and an engaging groove 255b that extends in the circumferential direction on the outer peripheral surface.

[0062] The clutch mechanism 256 includes a clutch rod 260 and a selector 262. The clutch rod 260 extends in the left-right direction and penetrates the gear case 250 from the inside to the outside. The clutch rod 260 is held by the gear case 250 so as to be slidable in the left-right direction. The left end of the clutch rod 260 is disposed to face the cam portion 300 (see FIG. 12) of the clutch operating mechanism 174. A selector 262 is fixed to the right end of the clutch rod 260. The selector 262 is engaged with the engagement groove 255b of the dog clutch 255.

[0063] The differential mechanism 258 includes a ring gear 258a, a pinion case 258b, a pinion shaft 258c, a pinion gear 258d, a right drive gear 258e, and a left drive gear 258f. The ring gear 258a meshes with the second gear 254 of the intermediate shaft 252. The pinion case 258b is screwed and fixed to the ring gear 258a and rotates integrally with the ring gear 258a. The ring gear 258a is rotatably held by the gear case 250, and the pinion case 258b is rotatably held by the gear case 250. The pinion shaft 258c is rotatably held by the pinion case 258b. The pinion gear 258d is fixed to the pinion shaft 258c. The right drive gear 258e is fixed to the right drive shaft 184 and meshes with the pinion gear 258d. The left drive gear 258f is fixed to the left drive shaft 186 and meshes with the pinion gear 258d.

[0064] FIG. 10 shows a state in which a clutch operation lever 270 (see FIG. 12) of a clutch operation mechanism 174 (see FIG. 12) is attached to a left frame pipe 154 (see FIG. 12). In this state, an engaging convex portion 255a of a dog clutch 255 is engaged with an engaging concave portion 254a of a second gear 254. When a first gear 253 rotates, the second gear 254 also rotates. Therefore, power from a motor shaft 246 is transmitted to a ring gear 258a of a differential mechanism 258 via an intermediate shaft 252. In this case, the differential mechanism 258 rotates a right drive shaft 184 and a left drive shaft 186 respectively according to the power transmitted to the ring gear 258a.

[0065] FIG. 11 shows a state in which a clutch operation lever 270 (see FIG. 18) of a clutch operation mechanism 174 (see FIG. 18) is pulled out from a left frame pipe 154 (see FIG. 18). In this state, the engaging convex portion 255a of the dog clutch 255 is not engaged with the engaging concave portion 254a of the second gear 254. Even when the first gear 253 rotates, the second gear 254 does not rotate. Therefore, power from the motor shaft 246 is not transmitted to the ring gear 258a of the differential mechanism 258.

[0066] Hereinafter, a state in which the engaging convex portion 255a of the dog clutch 255 is engaged with the engaging concave portion 254a of the second gear 254 (see FIG. 10) is also referred to as a "transmission state", and a state in which the engaging convex portion 255a of the dog clutch 255 is not engaged with the engaging concave portion 254a of the second gear 254 (see FIG. 11) is also referred to as a "non - transmission state". As described above, in the transmission state, the driving force from the motor 170 is transmitted to the right front wheel 160 and the left front wheel 162 via the right drive shaft 184 and the left drive shaft 186. On the other hand, in the non - transmission state, the driving force from the motor 170 is not transmitted to the right front wheel 160 and the left front wheel 162.

[0067] The user can switch the state of the clutch mechanism 256 (see FIG. 10) from the transmission state to the non - transmission state by operating the clutch operation lever 270 (see FIG. 12) of the clutch operation mechanism 174. However, as shown in FIG. 14, when the height of the protruding portion 306 of the rod operation portion 274 is the same as the height of the second extension portion 238b of the rotation plate 212, even if the user tries to perform an operation of pulling out the clutch operation lever 270 (see FIG. 12) from the left - hand frame pipe 154 (hereinafter sometimes referred to as "clutch release operation"), the protruding portion 306 of the rod operation portion 274 contacts the second extension portion 238b of the rotation plate 212, and the clutch operation lever 270 cannot be pulled out from the left - hand frame pipe 154.

[0068] As shown in FIG. 7, when the user pulls up the brake lever 58 of the left - hand handle 24, the inner cable 100a of the brake cable 100 is relatively drawn into the outer cable 100b. As shown in FIG. 13, the input arm 214a of the first link member 214 rotates in the direction of moving rightward, and the output arm 214b of the first link member 214 moves leftward. Therefore, the tip of the output arm 214b separates from the protruding portion 230a of the rotation plate 212. At the same time, the input arm 216a of the second link member 216 rotates in the direction of moving leftward, and the output arm 216b of the second link member 216 moves rightward. Therefore, the tip of the output arm 216b separates from the protruding portion 230b of the rotation plate 212. In this case, as shown in FIG. 19, due to the biasing force of the spring 230d of the rotation plate 212, the front part of the rotation plate 212 is pushed downward with respect to the support plate 210. As a result, as shown in FIG. 20, the protruding portion 296 of the rod operation portion 274 comes to be located above the second extension portion 238b of the rotation plate 212. For this reason, even if the clutch operation lever 270 is operated, the protruding portion 306 of the rod operation portion 274 does not contact the second extension portion 238b of the rotation plate 212. Therefore, the user can pull out the clutch operation lever 270 from the left - hand frame pipe 154.

[0069] As shown in FIG. 17, when the clutch operation lever 270 is pulled out from the left frame pipe 154, the clutch operation lever 270 rotates in the direction of moving leftward, so the connecting portion 302 of the rod operation portion 274 rotates in the direction of moving leftward about the rotation shaft 288. When the connecting portion 302 rotates in the direction of moving leftward, the cam portion 300 of the rod operation portion 274 rotates in the direction in which the cam surface 300a moves the clutch rod 260 to the right. As a result, as shown in FIG. 11, the clutch rod 260 is pushed into the gearbox 172, the selector 262 moves rightward, and the engaging convex portion 255a of the dog clutch 255 is disengaged from the engaging concave portion 254a of the second gear 254. Thereby, the state of the clutch mechanism 256 is switched from the transmission state to the non - transmission state.

[0070] As shown in FIG. 21, in the state where the state of the clutch mechanism 256 (see FIG. 11) is the non - transmission state, the left end portion of the clutch operation lever 270 is located between the left front wheel 162 and the left rear wheel 326. Also, the left end portion of the clutch operation lever 270 is located to the left of the left end portion of the loading platform frame 502. In this case, as shown in FIG. 18, the user can visually recognize the left end portion of the clutch operation lever 270 while gripping the right grip 32 and the left grip 52. That is, it can be known that the clutch mechanism 256 (see FIG. 11) is in the non - transmission state. On the other hand, as shown in FIG. 1, when the clutch operation lever 270 is attached to the left frame pipe 154, the user cannot visually recognize the left end portion of the clutch operation lever 270 while gripping the right grip 32 and the left grip 52. Incidentally, the torsion spring 292 (see FIG. 12) of the clutch operation lever 270 biases the left end portion of the clutch operation lever 270 in the rightward direction when the left end portion of the clutch operation lever 270 is pulled out to the left of the left front wheel 162. Thereby, the left end portion of the clutch operation lever 270 being located to the left of the left front wheel 162 is suppressed.

[0071] In one or more embodiments, as shown in FIGS. 2 and 10 to 13, a carrier 2 (an example of a "working machine") includes a left front wheel 162 (an example of a "first grounding portion") that contacts the ground, a motor 170 (an example of a "driving portion") that drives the left front wheel 162, a transmission state in which the driving force from the motor 170 is transmitted to the left front wheel 162, a non-transmission state in which the driving force from the motor 170 is not transmitted to the left front wheel 162, a clutch mechanism 256 that can be switched to any of these states, a clutch operation mechanism 174 (an example of a "clutch operation portion") for switching the state of the clutch mechanism 256, a braking state in which the left front wheel 162 is being braked, a non-braking state in which the left front wheel 162 is not being braked, a left front wheel brake 166 (an example of a "braking mechanism") that can be switched to any of these states, and a brake operation mechanism 56 (an example of a "braking operation portion") for switching the state of the left front wheel brake 166. When the state of the left front wheel 162 is the braking state, by operating the clutch operation mechanism 174, the state of the clutch mechanism 256 can be switched from the transmission state to the non-transmission state. When the state of the left front wheel 162 is the non-braking state, even if the clutch operation mechanism 174 is operated, the state of the clutch mechanism 256 cannot be switched from the transmission state to the non-transmission state. According to the above configuration, the state of the clutch mechanism 256 can be switched from the transmission state to the non-transmission state only when the state of the left front wheel brake 166 is the braking state, and when the state of the left front wheel brake 166 is the non-braking state, the state of the clutch mechanism 256 cannot be switched from the transmission state to the non-transmission state. Therefore, when the state of the clutch mechanism 256 is switched from the transmission state to the non-transmission state, the left front wheel 162 is being braked by the left front wheel brake 166. Accordingly, even if the state of the clutch mechanism 256 is switched from the transmission state to the non-transmission state, the carrier 2 can maintain its stopped state. In particular, the carrier 2 is used for transporting heavy objects (e.g., a large amount of sand, etc.). For this reason, it is desirable that even if the clutch mechanism 256 of the carrier 2 stopped on a slope is switched from the transmission state to the non-transmission state, the stopped state of the carrier 2 is maintained. According to the above configuration, even if the state of the clutch mechanism 256 is switched from the transmission state to the non-transmission state, the carrier 2 can maintain its stopped state

[0072] Also, in one or more embodiments, as shown in FIGS. 12 and 21, the clutch operating mechanism 174 switches the clutch mechanism 256 from a transmission state to a non - transmission state in response to a user's operation. For example, in the case where the clutch operating mechanism 174 uses power to switch the clutch mechanism 256 from a transmission state to a non - transmission state, if an abnormality occurs in the power system related to the clutch operating mechanism 174, the state of the clutch mechanism 256 cannot be switched from the transmission state to the non - transmission state. According to the above configuration, even when an abnormality occurs in a part of the power system related to the clutch operating mechanism 174, the user can manually operate the clutch operating mechanism 174 to switch the state of the clutch mechanism 256 from the transmission state to the non - transmission state. Therefore, the convenience of the user can be improved.

[0073] Also, in one or more embodiments, as shown in FIG. 12, the clutch operating mechanism 174 includes a clutch operating lever 270 that can be operated by the user. In response to the user's operation on the clutch operating lever 270, the state of the clutch mechanism 256 is switched from a non - transmission state to a transmission state. According to the above configuration, the configuration for operating the clutch mechanism 256 can be simplified.

[0074] Also, in one or more embodiments, as shown in FIGS. 12 and 13, the brake operation mechanism 56 switches the state of the left front wheel brake 166 from a non-braking state to a braking state in response to a user's operation. For example, when the brake operation mechanism 56 is configured to switch the left front wheel brake 166 from a non-braking state to a braking state using electric power, if an abnormality occurs in the power system related to the brake operation mechanism 56, the state of the left front wheel brake 166 cannot be switched from the non-braking state to the braking state, and as a result, the state of the clutch mechanism 256 cannot be switched from the transmission state to the non-transmission state. According to the above configuration, even when an abnormality occurs in the power system related to the brake operation mechanism 56, the user can switch the state of the left front wheel brake 166 from the non-braking state to the braking state, and as a result, the state of the clutch mechanism 256 can be switched from the transmission state to the non-transmission state. Therefore, the convenience for the user can be improved.

[0075] Also, in one or more embodiments, as shown in FIG. 2, the brake operation mechanism 56 includes a brake lever 58 that can be operated by the user. As shown in FIGS. 12 and 13, the state of the left front wheel brake 166 is switched from a non-braking state to a braking state in response to a user's operation on the brake lever 58. According to the above configuration, the configuration for operating the left front wheel brake 166 can be simplified.

[0076] Also, in one or more embodiments, as shown in FIG. 2, the carrier 2 further includes a right handle 22 and a left handle 24 (an example of a "grasping portion") that can be grasped by a user. When the user is grasping the right handle 22 and the left handle 24, and the clutch mechanism 256 is in a non-transmitting state, the clutch operating mechanism 174 is arranged such that the left end portion (an example of "at least a part") of the clutch operating mechanism 174 is in a visible position (see FIGS. 18 and 21). When the user is grasping the right handle 22 and the left handle 24, and the clutch mechanism 256 is in a transmitting state, the clutch operating mechanism 174 is arranged at a position where the user cannot visually recognize the clutch operating mechanism 174 (see FIG. 1). According to the above configuration, the user can grasp the state of the clutch mechanism 256 according to whether the left end portion of the clutch operating mechanism 174 can be visually recognized. Therefore, the convenience for the user can be improved.

[0077] Also, in one or more embodiments, as shown in FIG. 21, the carrier 2 further includes a left rear wheel 326 (an example of a "second grounding portion") that is provided behind the left front wheel 162 and contacts the ground. When the clutch mechanism 256 is in a non-transmitting state, the left end portion of the clutch operating mechanism 174 is arranged between the left front wheel 162 and the left rear wheel 326. According to the above configuration, since the left end portion of the clutch operating mechanism 174 is provided between the left front wheel 162 and the left rear wheel 326, the user can easily visually recognize at least a part of the clutch mechanism 256.

[0078] Also, in one or more embodiments, as shown in FIG. 18, the carrier 2 further includes a loading platform frame 502 (an example of a "support frame"). When the clutch mechanism 256 is in a non-transmitting state, when the carrier 2 is viewed from above, the left end portion of the clutch operating mechanism 174 is arranged outside the loading platform frame 502. According to the above configuration, since the left end portion of the clutch operating mechanism 174 is provided outside the loading platform frame 502, the user can easily visually recognize the left end portion of the clutch operating mechanism 174.

[0079] (First Modified Example) The "working machine" is not limited to the transport vehicle 2 and may be a sprayer or a lawn mower.

[0080] (Second Modified Example) The "ground contact part" is not limited to the wheels and may be a roller, a crawler, etc. extending in the left - right direction.

[0081] (Third Modified Example) Instead of, or in addition to, the brake lever 58, the transport vehicle 2 may be provided with a brake change - over switch for switching the states of the right front - wheel brake 164 and the left front - wheel brake 166.

[0082] (Fourth Modified Example) Instead of, or in addition to, the clutch operation mechanism 174, the transport vehicle 2 may be provided with a clutch change - over switch for switching the state of the clutch mechanism 256.

[0083] (Fifth Modified Example) The right front - wheel brake 164 and the left front - wheel brake 166 may be electric parking brakes.

[0084] (Sixth Modified Example) A user holding the right handle 22 and the left handle 24 may be able to visually recognize at least a part of the clutch operation mechanism 174 in both the transmission state and the non - transmission state. Also, in another modified example, a user holding the right handle 22 and the left handle 24 may not be able to visually recognize the clutch operation mechanism 174 in both the transmission state and the non - transmission state.

[0085] (Seventh Modified Example) The transport vehicle 2 may not be provided with the fixing lever 64.

[0086] (Eighth Embodiment) The transport vehicle 2 may be provided with an actuator for switching the states of the right front - wheel brake 164 and the left front - wheel brake 166. In this modified example, the control device 12b may control the operation of the actuator.

[0087] (Example 9) The transport vehicle 2 may be provided with an actuator for switching the state of the clutch mechanism 256. In this modification, the control device 12b may control the operation of the actuator.

Explanation of Signs

[0088] 2: Carrier, 4: Chassis Unit, 6: Loading Platform Unit, 10: Handle Unit, 12: Battery Box, 12a: Battery Pack, 12b: Control Device, 14: Chassis Frame, 16: Front Wheel Unit, 18: Rear Wheel Unit, 20: Handle Base, 22: Right Handle, 24: Left Handle, 30: Right Pipe, 30a: Right Support Portion, 30b: Right Handle Portion, 32: Right Grip, 34: Switch Box, 36: Drive Lever, 38: Right Casing, 40: Operation Panel, 40a: Main Power Switch, 40b: Reverse Switch, 40c: Speed Switch, 42: Drive Switch, 50: Left Pipe, 50a: Left Support Portion, 50b: Left Handle Portion, 52: Left Grip, 54: Left Casing, 54a: Opening, 56: Brake Operation Mechanism, 58: Brake Lever, 60: First Link Member, 62: Cable Holding Portion, 64: Fixing Lever, 66: Operation Portion, 66a: Concave Portion, 66b: First Protrusion, 66c: Second Protrusion, 68: Support Portion, 68a: Left Spring Receiving Portion, 68b: Right Spring Receiving Portion, 70: Bearing Holding Portion, 70a: Right Wall Portion, 70b: Left Wall Portion, 70c: Shaft, 72: Rotation Axis, 74: Spring, 76: Bearing, 80: Support Portion, 82: First Extension Portion, 82a: Through Hole, 84: Second Extension Portion, 84a: Upper Surface, 86: Rotation Axis, 90: Right Wall Portion, 92: Left Wall Portion, 94: Front Wall Portion, 94a: Notch, 96: Shaft, 100: Brake Cable, 100a: Inner Cable, 100b: Outer Cable, 110: Operation Portion, 112: Support Portion, 114: Protrusion, 116: Spring Receiving Portion, 118: Rotation Axis, 120: Spring, 130: Stop Switch, 130a: Switch Portion, 132: Second Link Member, 132a: One End, 132b: The Other End, 134: Signal Cable, 150: Frame Plate, 152: Right Frame Pipe, 154: Left Frame Pipe, 156: Central Frame Pipe, 158: Cable Cover, 160: Right Front Wheel, 160a: Hub, 162: Left Front Wheel, 162a: Hub, 164: Right Front Wheel Brake, 166: Left Front Wheel Brake, 168: Brake Equalizer, 170: Motor, 171: Electromagnetic Brake Case, 172: Gear Box, 174: Clutch Operation Mechanism, 176: Right Headlamp, 178: Left Headlamp, 180: Right Axle Case, 182: Left Axle Case, 184: Right Drive Shaft, 186: Left Drive Shaft, 188: Right Bracket,190: Left bracket, 192: Disc rotor, 194: Brake caliper, 196: Right brake cable, 196a: Inner cable, 196b: Outer cable, 198: Disc rotor, 200: Brake caliper, 202: Left brake cable, 202a: Inner cable, 202b: Outer cable, 210: Support plate, 212: Rotating plate, 214: First link member, 214a: Input arm, 214b: Output arm, 216: Second link member, 216a: Input arm, 216b: Output arm, 218: Bracket, 220: Base portion, 220a: Opening, 220b: Opening, 222: Right extension, 224: Left extension, 226: Rotation axis, 230: Upper wall portion, 230a: Protrusion, 230b: Protrusion, 230c: Spring receiving portion, 230d: Spring, 232: Right wall portion, 234: Left wall portion, 236: Rear wall portion, 238: Extension, 238a: First extension, 238b: Second extension, 239: Rotation axis, 240: Stator, 242: Rotor, 244: Motor case, 246: Motor shaft, 246a: Spur gear, 250: Gear case, 252: Intermediate shaft, 253: First gear, 254: Second gear, 254a: Engagement recess, 255: Dog clutch, 255a: Engagement protrusion, 255b: Engagement groove, 256: Clutch mechanism, 258: Differential mechanism, 258a: Ring gear, 258b: Pinion case, 258c: Pinion shaft, 258d: Pinion gear, 258e: Right drive gear, 258f: Left drive gear, 260: Clutch rod, 262: Selector, 270: Clutch operation lever, 270a: Mounting portion, 272: Support bracket, 274: Rod operation portion, 280: Base portion, 280a: Through hole, 280b: Through hole, 282: Rightward extension, 284: Mounting portion, 286: Rotation axis, 288: Rotation axis, 290: Rotation axis, 292: Spring, 300: Cam portion, 300a: Cam surface, 302: Connecting portion, 304: Connection portion, 306: Protrusion, 320: Base plate, 322: Hinge, 324: Right rear wheel, 326: Left rear wheel, 400: Electromagnetic brake, 402: Key, 404: Hub, 406: Disc rotor, 408: Plate, 408a: First plate, 408b: Second plate, 410: Electromagnet, 410a: Spring receiving portion, 412: Armchair, 414: Spring, 500: Bucket, 502: Loading platform frame

Claims

1. a first grounding portion grounded to the ground; a driving portion for driving the first grounding portion; a clutch mechanism capable of switching between a transmission state in which the driving force from the driving portion is transmitted to the first grounding portion and a non - transmission state in which the driving force is not transmitted to the first grounding portion; a clutch operation portion for switching the state of the clutch mechanism; a braking mechanism capable of switching between a braking state in which the first grounding portion is being braked and a non - braking state in which the first grounding portion is not being braked; and a braking operation portion for switching the state of the braking mechanism, when the state of the braking mechanism is the braking state, by operating the clutch operation portion, the state of the clutch mechanism can be switched from the transmission state to the non - transmission state, when the state of the braking mechanism is the non - braking state, even if the clutch operation portion is operated, the state of the clutch mechanism cannot be switched from the transmission state to the non - transmission state, a working machine.

2. The working machine according to claim 1, wherein the clutch operation portion switches the state of the clutch mechanism from the transmission state to the non - transmission state according to an operation of a user.

3. The clutch operation portion includes a clutch operation lever operable by the user, The working machine according to claim 2, wherein the state of the clutch mechanism is switched from the non - transmission state to the transmission state according to an operation of the user on the clutch operation lever.

4. The working machine according to any one of claims 1 to 3, wherein the braking operation portion switches the state of the braking mechanism from the non - braking state to the braking state according to an operation of a user.

5. The braking operation portion includes a braking operation lever operable by the user, The working machine according to claim 4, wherein the state of the braking mechanism is switched from the non-braking state to the braking state in response to an operation of the user on the braking operation lever.

6. The working machine further comprises a gripping portion that can be gripped by the user, when the user is gripping the gripping portion and the state of the clutch mechanism is the non-transmission state, the clutch operation portion is arranged at a position where at least a part of the clutch operation portion is visible to the user, when the user is gripping the gripping portion and the state of the clutch mechanism is the transmission state, the clutch operation portion is arranged at a position where the user cannot visually recognize the clutch operation portion. The working machine according to any one of claims 1 to 5.

7. The working machine further comprises a second grounding portion provided in front of or behind the first grounding portion and grounding to the ground, when the state of the clutch mechanism is the non-transmission state, at least a part of the clutch operation portion is arranged between the first grounding portion and the second grounding portion. The working machine according to claim 6.

8. The working machine further comprises a support frame, when the state of the clutch mechanism is the non-transmission state, when the working machine is viewed from above, at least a part of the clutch operation portion is arranged outside the support frame. The working machine according to claim 6 or 7.

9. The working machine is a transport vehicle. The working machine according to any one of claims 1 to 8.

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