Walk-behind work machine

Abstract

To reduce burden (a load) applied to an operator while securing operability of a handle rod for the operator even when the operator is located between the handle rod and an obstacle behind the operator.SOLUTION: A walking type work machine 100 includes: a vehicle body 10 including a wheel 13 that travels by using power from an engine 14 for performing predetermined work; a handle rod 30 including a front portion 30a having one end fixed to the vehicle body 10 and extending rearward in an advance direction of the vehicle body 10, and a rear portion 30b provided in another end of the front portion 30a and configured to be gripped by an operator, the rear portion 30b configured to rotate relatively to the front portion 30a; a gas spring 32 that provides the rear portion 30b with a force against rotation of the rear portion 30b while allowing the rotation; and clutch wire 35 and switch 38 that stop the wheel 13 in conjunction with the rotation of the rear portion 30b.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a walk-behind working machine. [Background technology]

[0002] Walk-behind working machines are known in which an operator follows the machine while gripping a handlebar provided at the rear of the machine in the forward direction, and performs work using a working unit provided on the machine body. There are times when the operator moves the walk-behind working machine in reverse to change the direction of the machine (such as turning or reversing in a pinch), align rows, or take the machine in or out of a warehouse. Conventionally, safety devices have been known that prevent the operator from being pinched and crushed between the handlebar and an obstacle behind the walk-behind working machine when the walk-behind working machine is moving in reverse.

[0003] As a safety device, for example, a configuration has been proposed in which, when an external force greater than a predetermined value is applied, the rear part of the handlebar bends, and in conjunction with this bending, the clutch wire is loosened and the clutch is disengaged (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-23701 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have newly discovered that if a worker is caught between the handlebar and an obstacle behind the walk-behind work machine while the machine is moving backward, the greatest force is applied to the worker in a short time after the worker is caught. However, even if the rear portion of the handlebar bends and the clutch is disengaged when an external force of a predetermined value or greater is applied to the handlebar, as in the technology disclosed in Patent Document 1, it is difficult to stop the machine from moving backward instantly after the worker is caught. This raises the risk of a large load (weight) being applied to the worker.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a walk-behind working machine that can reduce the load (weight) on the worker while still allowing the worker to operate the handlebar, even if the worker is pinched between the handlebar and an obstacle behind the worker. [Means for solving the problem]

[0007] The walk-behind working machine of the present invention has a vehicle body having a traveling section that travels using the power of a drive section and performs a predetermined task, a first section having one end fixed to the vehicle body and extending rearward in the forward direction of the vehicle body, and a second section provided at the other end of the first section and grasped by an operator, a handle rod by which the second section rotates relative to the first section, a restricting section that applies a force to the second section that resists the rotation while allowing the rotation of the second section, and a stop section that stops the traveling section from moving in conjunction with the rotation of the second section. a lock operation portion for preventing the second portion from rotating; Equipped with The lock operation portion releases the prevention of rotation of the second portion when the vehicle body is moved backward. . The walk-behind working machine of the present invention has a vehicle body having a running part that runs using the power of a drive part and performs specified work, a first part having one end fixed to the vehicle body and extending rearward in the forward direction of the vehicle body, and a second part provided at the other end of the first part and gripped by an operator, a handle rod by which the second part rotates relative to the first part, a regulating part that applies a force to the second part that resists the rotation while allowing the second part to rotate, a stop part that stops the running of the running part in conjunction with the rotation of the second part, and a lock operating part for preventing the rotation of the second part, wherein the lock operating part releases the prevention of the rotation of the second part when a load greater than the initial reaction force of the regulating part is applied to the second part when the vehicle body is moving backward. The walk-behind working machine of the present invention has a vehicle body having a running part that runs using the power of a drive part and performs specified work, a first part having one end fixed to the vehicle body and extending rearward in the forward direction of the vehicle body, and a second part provided at the other end of the first part and grasped by an operator, a handle rod that rotates the second part relative to the first part, a regulating part that allows the second part to rotate while applying a force to the second part that resists the rotation, and a stop part that stops the running of the running part in conjunction with the rotation of the second part, wherein the regulating part is a gas spring or a shock absorber. The walk-behind working machine of the present invention has a vehicle body having a running part that runs using the power of a drive part and performs specified work, a first part that is fixed at one end to the vehicle body and extends rearward in the forward direction of the vehicle body, and a second part that is provided at the other end of the first part and is gripped by an operator, a handle rod that rotates with respect to the first part, a regulating part that applies a force to the second part that resists the rotation while allowing the second part to rotate, and a stopping part that stops the running of the running part in conjunction with the rotation of the second part, wherein the drive part is an engine, and the stopping part stops the supply of power to an ignition plug of the engine in conjunction with the rotation of the second part. The walk-behind working machine of the present invention has a vehicle body having a running part that runs using the power of a drive part and performs specified work, a first part that is fixed at one end to the vehicle body and extends rearward in the forward direction of the vehicle body, and a second part that is provided at the other end of the first part and is gripped by an operator, a handle rod that causes the second part to rotate relative to the first part, a regulating part that applies a force to the second part that resists the rotation while allowing the second part to rotate, and a stopping part that stops the running of the running part in conjunction with the rotation of the second part, wherein the drive part is an engine, and the stopping part in conjunction with the rotation of the second part stops the supply of power to an ignition plug that the engine has and disengages a clutch that transmits the power of the engine to the running part. [Effects of the Invention]

[0008] The walk-behind working machine of the present invention has the advantage of being able to reduce the load (weight) on the worker while still allowing the worker to operate the handlebar, even if the worker is pinched between the handlebar and an obstacle behind the worker. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a walk-behind working machine according to a first embodiment as viewed from the +Y direction. [Figure 2] FIG. 2 is a diagram showing the walk-behind working machine according to the first embodiment as viewed from the +Z direction. [Figure 3] FIG. 3 is a diagram showing the walk-behind working machine according to the first embodiment as viewed obliquely from above. [Figure 4] 4(a) and 4(b) are diagrams showing the vicinity of the gearshift lever. [Figure 5] 5(a) and 5(b) are diagrams showing the lock switching mechanism when the gearshift lever is set to a position other than reverse. [Figure 6] 6(a) and 6(b) are diagrams showing the lock switching mechanism when the gearshift lever is set to reverse. [Figure 7] FIG. 7(a) is a diagram showing the gas spring in the first embodiment in a locked state, and FIG. 7(b) is a diagram showing the gas spring in the first embodiment in an unlocked state. [Figure 8] FIG. 8 is a diagram showing the handle rod in the walk-behind working machine of the first embodiment in a state before the clutch rod is gripped. [Figure 9] FIG. 9 is a diagram showing the handlebar of the walk-behind working machine of the first embodiment when the speed change lever is in a position other than R (reverse) and the clutch rod is gripped. [Figure 10] FIG. 10 is a diagram showing the handlebar of the walk-behind working machine of the first embodiment in a state where the speed change lever is in R (reverse) and the clutch rod is gripped. [Figure 11] FIG. 11 is a diagram showing the handle of the walk-behind working machine of the first embodiment in a state where the operator is pinched between the handle and an obstacle behind the operator when the walk-behind working machine is moving backward. [Figure 12] 12(a) and 12(b) are enlarged views of area A in FIG. [Figure 13] FIG. 13 is a graph showing the change in the load (weight) applied to the worker after the worker begins to be pinched between the handlebar and an obstacle behind the worker when the walk-behind working machine is moving backward. [Figure 14] FIG. 14 is a diagram showing the walk-behind working machine according to the second embodiment as viewed obliquely from above. [Figure 15] 15(a) and 15(b) are cross-sectional views showing the gas spring according to the first embodiment. [Figure 16]FIG. 16 is a diagram showing the walk-behind working machine according to the third embodiment as viewed from the +Z direction. [Figure 17] 17(a) and 17(b) are enlarged views of the vicinity of the display panel in the third embodiment. [Figure 18] FIG. 18 is a diagram showing the handle rod in the walk-behind working machine of the fourth embodiment in a state before the clutch rod is gripped. [Figure 19] 19(a) is an enlarged view of area A in FIG. 18, and FIG. 19(b) is an enlarged view of the vicinity of the link mechanism in FIG. 19(a) as viewed from direction A. [Figure 20] FIG. 20 is a diagram showing the handle rod in the walk-behind working machine of the fourth embodiment when the speed change lever is in R (reverse) and the clutch rod is gripped. [Figure 21] FIG. 21 is an enlarged view of area A in FIG. [Figure 22] FIG. 22 is a diagram showing the handle of the walk-behind working machine of the fourth embodiment in a state where the operator is pinched between the handle and an obstacle behind the operator when the machine is moving backward. [Figure 23] FIG. 23 is an enlarged view of area A in FIG. [Figure 24] 24(a) and 24(b) are diagrams showing a modified example of the lock operating portion in a state before the clutch rod is gripped. [Figure 25] 25(a) and 25(b) are diagrams showing a lock operation portion according to a modified example in a state where the shift lever is in R (reverse) and the clutch rod is gripped. [Figure 26] 26(a) and 26(b) are views showing the lock operation portion according to the modified example immediately after the ball of the ball plunger has come out of the recess. [Figure 27] 27(a) and 27(b) are views showing the lock operation portion according to the modified example a short time after the ball of the ball plunger has come out of the recess. [Figure 28] 28(a) and 28(b) are diagrams showing a lock operation portion according to a modified example in a state where the gas spring is greatly compressed. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment A walk-behind working machine 100 according to a first embodiment will now be described with reference to the drawings. The walk-behind working machine 100 of this first embodiment is, for example, a walk-behind tiller (walk-behind tractor) that is powered by a motor for automatic travel and performs tilling work while automatically traveling. Note that the walk-behind working machine 100 may also be a walk-behind working machine other than a walk-behind tiller, such as a walk-behind snow blower or a walk-behind rice transplanter. Furthermore, the walk-behind working machine 100 of this first embodiment is a one-axle, two-wheel walk-behind working machine having two wheels, but is not limited to this and may also be, for example, a two-axle, four-wheel walk-behind working machine having four wheels, a crawler walk-behind working machine, or the like.

[0011] Figures 1 to 3 show a schematic configuration of a walk-behind working machine 100. In Figures 1 to 3, the forward direction of the walk-behind working machine 100 is the +X direction, the backward direction is the -X direction, the direction perpendicular to the X axis in a horizontal plane (left-right direction) is the Y axis direction, and the vertical direction is the Z axis direction. Figure 1 shows the walk-behind working machine 100 as seen from the +Y direction, Figure 2 shows the walk-behind working machine 100 as seen from the +Z direction, and Figure 3 shows the walk-behind working machine 100 as seen from diagonally above.

[0012] 1, the walk-behind work machine 100 includes a body 10, a working unit 11 provided at the rear of the body 10 in the forward direction (-X side), an axle 12 provided on the body 10 as a drive shaft extending in the Y-axis direction, wheels 13 provided at both ends of the axle 12, a motor 14 provided on the body 10, a speed change lever 15 provided on the body 10, and a handle bar 30 provided on the -X side of the body 10 and held by an operator. The motor 14 is a drive unit that rotates the wheels 13 and the tiller tines 16 of the work unit 11. In addition to the motor 14, the body 10 also holds devices necessary for rotating the wheels 13 and the tiller tines 16, such as a fuel tank and a muffler.

[0013] The working unit 11 is a rotary tiller having tiller tines 16. The tiller tines 16 rotate using power from an engine 14. The working unit 11 moves up and down around the wheels 13 when the operator moves the handlebar 30 up and down. When tilling, the operator lowers the working unit 11 downward so that the tiller tines 16 penetrate the soil. For safety reasons, the walk-behind working machine 100 is designed so that the tiller tines 16 do not operate when the machine is reversing. Alternatively, the walk-behind working machine 100 cannot be reversing when the tiller tines 16 are operating.

[0014] The wheels 13 rotate by power supplied from the engine 14 via a clutch (not shown) to an axle 12 provided between the engine 14 and the wheels 13. The wheels 13 are the running parts that make the vehicle body 10 move. In addition, the clutch is provided between the engine 14 and the wheels 13, and mechanically transmits and interrupts power from the engine 14 to the wheels 13.

[0015] The speed change lever 15 is a switch that changes the rotation direction and speed of the wheels 13, and is provided near the handlebar 30. The operator can change the operating mode by operating the speed change lever 15 along the groove 18 (see Figures 4(a) and 4(b)) provided in the display panel 17, and can move the walk-behind working machine 100 forward or backward.

[0016] 2 and 3, the handlebar 30 has a front portion 30a that is fixed at one end to the vehicle body 10 and extends rearward in the forward movement direction of the vehicle body 10, and a rear portion 30b that is attached to the other end of the front portion 30a and is gripped by an operator. The rear portion 30b is attached to the front portion 30a in a state that allows it to rotate vertically downward relative to the front portion 30a (rotatable around the Y axis).

[0017] The handlebar 30 is provided with a clutch rod 31, a gas spring 32, and a lock switching mechanism 33. Although not shown, the handlebar 30 is also provided with an engine switch.

[0018] The clutch rod 31 is disposed above the rear portion 30b of the handle rod 30 so that the operator can grasp it together with the rear portion 30b of the handle rod 30. The clutch rod 31 is attached to the rear portion 30b of the handle rod 30 and is rotatable about a rotation axis provided on the underside of the rear portion 30b of the handle rod 30. The clutch rod 31 is connected to the clutch via a clutch wire 35. An inner wire 35a (the inner portion covered by the outer cable 35b) of the clutch wire 35 is connected to the clutch rod 31. An inner wire 52a of a connecting wire 52 is also connected to the clutch rod 31. The inner wire 35a and the inner wire 52a are connected to the clutch rod 31 on the opposite side of the rear portion 30b of the handle rod 30 from the rotation axis of the clutch rod 31 provided on the underside of the rear portion 30b of the handle rod 30. Furthermore, the end of the outer cable 35b of the clutch wire 35 is attached at a position such that the distance from the end of the outer cable 35b to the attachment position of the inner wire 35a to the clutch rod 31 becomes small when the operator releases the clutch rod 31 or when the rear portion 30b of the handlebar rod 30 rotates relative to the front portion 30a as described below. The same is true for the connecting wire 52. For example, the end of the outer cable 35b of the clutch wire 35 and the end of the outer cable 52b of the connecting wire 52 are attached to the underside of the front portion 30a of the handlebar rod 30. When the operator grips the clutch rod 31 together with the rear portion 30b of the handlebar rod 30, the inner wire 35a of the clutch wire 35 is pulled, the clutch is engaged, and power is transmitted from the engine 14 to the axle 12 (a transmitted state is established). On the other hand, when the operator releases the clutch rod 31, the inner wire 35a of the clutch wire 35 loosens, the clutch is disengaged, and the transmission of power from the engine 14 to the axle 12 is interrupted (a disconnected state is established). In this way, the operator can control the travel of the walk-behind working machine 100 by operating the clutch rod 31.

[0019] The gas spring 32 is a spring that uses the reaction force of compressed gas, and one end of the gas spring 32 is provided with a lock operation unit 34 (see Figures 7(a) and 7(b)) that switches the gas spring 32 between a state in which it cannot expand or contract (locked state) and a state in which it can expand or contract (unlocked state). Figure 7(a) shows the gas spring 32 in the locked state, and Figure 7(b) shows the gas spring 32 in the unlocked state.

[0020] As shown in FIG. 3 , one end of the gas spring 32 is connected to a fixed member 37 provided on the rear portion 30b of the handle rod 30. The fixed member 37 extends diagonally downward in a direction (in the XZ plane) perpendicular to the longitudinal direction (Y-axis direction) of the rear portion 30b of the handle rod 30, and one end of the gas spring 32 is swingably connected to the vicinity of an end of the fixed member 37 on the extending side that is located below the pivot axis about which the rear portion 30b rotates relative to the front portion 30a. The other end of the gas spring 32 is connected to a fixed member 36 provided on the front portion 30a of the handle rod 30. The fixed member 36 is a plate-shaped member whose longitudinal direction is in the Y-axis direction, and the other end of the gas spring 32 is swingably connected to a central portion of the fixed member 37 in the longitudinal direction.

[0021] FIGS. 15(a) and 15(b) show cross-sectional views of the gas spring 32 according to the first embodiment. FIG. 15(a) is a cross-sectional view of the gas spring 32 in a locked state, and FIG. 15(b) is a cross-sectional view of the gas spring 32 in an unlocked state. As shown in FIGS. 15(a) and 15(b), the gas spring 32 has a cylinder 70 whose interior is divided by a free piston 71 into a space 72 filled with compressed gas such as nitrogen gas and a space 73 filled with oil. A piston 75 connected to a piston rod 74 is provided in the oil-filled space 73. The piston 75 is provided with an orifice hole 76 and a valve 77 that switches between allowing and not allowing oil to flow through the orifice hole 76. The valve 77 is connected to a push rod 78 provided inside the piston rod 74 and movable relative to the piston rod 74. The pressure of the compressed gas in the space 72 urges the piston 75 toward the piston rod 74. Furthermore, when no external force is applied to the push rod 78, the pressure of the compressed gas in the space 72 maintains the state in which the valve 77 is in contact with the piston 75 (the state in Figure 15(a)).

[0022] 7(a) and 7(b), the lock operating unit 34 includes a flange portion 39a attached to the end of the piston rod 74 of the gas spring 32, an arm 39c attached to the flange portion 39a so as to be pivotable about a rotation shaft 39b provided on the flange portion 39a, and a fixed portion 39d attached to the flange portion 39a and positioned closer to the piston rod 74 than the arm 39c. An inner wire 50a of the lock wire 50 is connected to the arm 39c. An end of an outer cable 50b of the lock wire 50 is attached to the fixed portion 39d. An end of a push rod 78 (not shown) is in contact with the arm 39c, and when the push rod 78 is in the state shown in FIG. 15(a), the arm 39c is biased counterclockwise around the rotation shaft 39b. As a result, unless the inner wire 50a is pulled, the arm 39c is maintained in the state shown in FIG. 7(a) (a state in which it has rotated counterclockwise around the rotation axis 39b relative to FIG. 7(b)). In this state, the valve 77 closes the orifice hole 76 provided in the piston 75, preventing oil from flowing through the orifice hole 76 and preventing the piston 75 from moving. Therefore, in the state shown in FIG. 7(a), the gas spring 32 is in a locked state. On the other hand, when the arm 39c is pulled by the inner wire 50a of the lock wire 50 and rotates clockwise around the rotation axis 39b as shown in FIG. 7(b), the push rod 78 is pushed toward the space 72 relative to the piston rod 74 as shown in FIG. 15(b), causing the valve 77 provided at the end of the push rod 78 to move away from the orifice hole 76. This allows oil to flow through the orifice hole 76, allowing the piston 75 to move. Therefore, in the state shown in FIG. 7(b), the gas spring 32 is in an unlocked state.

[0023] When the gas spring 32 is in a locked state (a state in which it cannot expand or contract), rotation of the rear portion 30b of the handle rod 30 is prevented. In contrast, when the gas spring 32 is in an unlocked state (a state in which it can expand or contract), when an external force of a predetermined value or greater is applied to the rear portion 30b of the handle rod 30, the rear portion 30b of the handle rod 30 is allowed to rotate relative to the front portion 30a, and a predetermined force resisting rotation is applied to the rear portion 30b. In other words, the resistance force generated when the gas spring 32 compresses acts as a force resisting rotation of the rear portion 30b of the handle rod 30. When the gas spring 32 compresses, oil passes through the orifice hole 76, and the resistance encountered when the oil passes through the orifice hole 76 generates a resistance force when the gas spring 32 compresses.

[0024] The lock switching mechanism 33 shown in FIGS. 2 and 3 is a mechanism that switches between a state in which the inner wire 50a of the lock wire 50 is not pulled or slightly pulled (see FIGS. 5(a), 5(b), and 6(a)) and a state in which the inner wire 50a is pulled strongly (see FIG. 6(b)), depending on the operator's operation of the shift lever 15 and the clutch rod 31. When the lock switching mechanism 33 is not pulled or slightly pulled on the inner wire 50a as shown in FIGS. 5(a), 5(b), and 6(a), the lock operating unit 34 is maintained in the state shown in FIG. 7(a) (locked state). On the other hand, when the lock switching mechanism 33 is in a state in which the inner wire 50a is pulled strongly as shown in FIG. 6(b), the lock operating unit 34 is in the state shown in FIG. 7(b) (unlocked state). Details of the lock switching mechanism 33 will be described later.

[0025] 4(a) and 4(b) show the vicinity of the shift lever 15. FIG. 4(a) shows the shift lever 15 in the N (neutral) position, and FIG. 4(b) shows the shift lever 15 in the R (reverse) position. As shown in FIGS. 4(a) and 4(b), an indicator plate 17 is provided near the lower end of the shift lever 15 (on the vehicle body 10). The shift lever 15 is movable along a groove 18 provided in the indicator plate 17. By setting the shift lever 15 to the N (neutral) position, an operator can set the vehicle to a mode in which the wheels 13 do not rotate, and by setting the shift lever 15 to the R (reverse) position, an operator can set the vehicle to a mode in which the vehicle body 10 moves backward. The R (reverse) position is located at one end of the groove 18. By setting the shift lever 15 to the L (low) position, the vehicle body 10 can be set to a mode in which it moves forward at a low speed, and by setting it to the H (high) position, the vehicle body 10 can be set to a mode in which it moves forward at a high speed. Note that there may be modes other than those shown in Figures 4(a) and 4(b).

[0026] A moving member 53 is provided near the shift lever 15. The moving member 53 moves as the shift lever 15 moves from the N (neutral) position between R (reverse) and L (low) to the R (reverse) position. The moving member 53 moves when a portion 53a of the moving member 53 is pushed when the shift lever 15 moves from the N (neutral) position between R (reverse) and L (low) to the R (reverse) position. An end of an inner wire 51a of a connecting wire 51 is connected to the moving member 53. An end of an outer cable 51b of the connecting wire 51 is attached to a fixed portion 17a fixed to the display panel 17 on the opposite side of the R (reverse) position with respect to the shift lever 15. When the shift lever 15 moves from the neutral (N) position between R (reverse) and L (low) to the R (reverse) position, the moving member 53 moves, and the inner wire 51a of the connecting wire 51 is pulled. As will be described in detail later, when the shift lever 15 returns to the N (neutral) position between R (reverse) and L (low), the movable member 53 also returns to its original position. In the state shown in FIG. 4(a), a portion 53a of the movable member 53 abuts against a stopper 17b fixed to the display panel 17, so the movable member 53 does not move even when the shift lever 15 moves from the N (neutral) position between R (reverse) and L (low) to L (low), to the neutral (N) position between L (low) and H (high), or to the H (high) position. Hereinafter, when the shift lever 15 is in the N (neutral) position, it means that the shift lever 15 is in the N (neutral) position between R (reverse) and L (low).

[0027] FIGS. 5(a) and 5(b) show the lock switching mechanism 33 when the gearshift lever 15 is set to a position other than R (reverse). FIGS. 6(a) and 6(b) show the lock switching mechanism 33 when the gearshift lever 15 is set to R (reverse). The lock switching mechanism 33 is attached to an end of the outer cable 51b of the connecting wire 51, an end of the outer cable 52b of the connecting wire 52, and an end of the outer cable 50b of the lock wire 50. The other end of the outer cable 51b of the connecting wire 51 is attached to a fixing portion 17a fixed to the display panel 17 as shown in FIGS. 4(a) and 4(b). The other end of the outer cable 52b of the connecting wire 52 is attached to the front portion 30a of the handlebar rod 30 as shown in FIG. 2. The other end of the outer cable 50b of the lock wire 50 is attached to a fixing portion 39d of the lock operating portion 34 as shown in FIGS. 7(a) and 7(b). The lock switching mechanism 33 causes the inner wire 50a of the lock wire 50 to be pulled to different degrees depending on the states of the connecting wires 51 and 52. As shown in Figure 6(b), when the inner wire 50a of the lock wire 50 is pulled to a greater extent by the lock switching mechanism 33, the arm 39c of the lock operating unit 34 pushes the push rod 78, opening the valve 77 and unlocking the gas spring 32. The lock switching mechanism 33 is described in detail below.

[0028] Fig. 5(a) shows a state in which the shift lever 15 is in a position other than R (reverse) (for example, N (neutral) position) and the clutch rod 31 is not gripped by the operator. Fig. 5(b) shows a state in which the shift lever 15 is in a position other than R (reverse) (for example, L (low) or H (high) position) and the clutch rod 31 is gripped by the operator. Fig. 6(a) shows a state in which the shift lever 15 is in the R (reverse) position and the clutch rod 31 is not gripped by the operator. Fig. 6(b) shows a state in which the shift lever 15 is in the R (reverse) position and the clutch rod 31 is gripped by the operator.

[0029] As shown in FIG. 5(a), the lock switching mechanism 33 includes a plate-shaped member 40, rotating members 41 and 42 provided on the plate-shaped member 40, and torsion coil springs 43 and 44. Ends of outer cables 51b and 52b of connection wires 51 and 52 are attached to the plate-shaped member 40. The plate-shaped member 40 has a generally rectangular shape when viewed from above, and includes four sides 40a, 40b, 40c, and 40d. Side 40a faces side 40b, and side 40c faces side 40d. The outer cable 51b of the connection wire 51 extends onto the plate-shaped member 40 from the side 40c, and the end of the outer cable 51b is attached to the plate-shaped member 40 near the corner between sides 40a and 40c. An outer cable 52b of the connecting wire 52 extends onto the plate-shaped member 40 from the side 40d, and an end of the outer cable 52b is attached to the plate-shaped member 40 near the corner between sides 40b and 40d. The rotating member 41 is provided between the rotating member 42 and side 40c of the plate-shaped member 40, and the rotating member 42 is provided between the rotating member 41 and side 40d of the plate-shaped member 40. The rotating member 41 is rotatable about a shaft 45 provided on the plate-shaped member 40. The rotating member 42 is rotatable about a shaft 46 provided on the plate-shaped member 40. The shaft 45 is located near side 40b, and the shaft 46 is located near side 40a.

[0030] A columnar portion 48 that functions as a stopper is provided between the rotating members 41 and 42. The outer cable 50b of the locking wire 50 extends onto the plate-shaped member 40 from the side 40c of the plate-shaped member 40, and the end of the outer cable 50b is fixed to the rotating member 41 near the center, in the direction along the side 40c, between the shaft 45 and the location where the end of the outer cable 51b of the connection wire 51 is attached to the plate-shaped member 40. The end of the inner wire 50a of the locking wire 50 is hooked into a notch 47 provided in the rotating member 42 near the center, in the direction along the side 40d, between the shaft 46 and the location where the end of the outer cable 52b of the connection wire 52 is attached to the plate-shaped member 40. With this configuration, when the state shown in FIG. 6(b) is achieved, the inner wire 52a of the connection wire 52 and the inner wire 51a of the connection wire 51 each pull approximately half of the inner wire 50a of the locking wire 50.

[0031] One end of the inner wire 51a of the connecting wire 51 is connected to the moving member 53 (see FIGS. 4(a) and 4(b)). The other end is hooked to a location on the rotating member 41 opposite the shaft 45. As shown in FIG. 4(b), when the operator moves the shift lever 15 to the R (reverse) position, the moving member 53 moves, and one end of the inner wire 51a is pulled, causing the other end of the inner wire 51a to pull the rotating member 41. As a result, as shown in FIGS. 6(a) and 6(b), the rotating member 41 rotates clockwise around the shaft 45. On the other hand, when the operator returns the shift lever 15 from the state shown in FIG. 4(b) to the N (neutral) position, the biasing force of the torsion coil spring 43, which rotates the rotating member 41 around the shaft 45 and applies a force to the rotating member 41 pressing it against the columnar portion 48, causes the rotating member 41 to return to its original position, as shown in FIGS. 5(a) and 5(b). As a result, the rotating member 41 pulls the other end of the inner wire 51a, and the moving member 53 also returns to its original position shown in FIG. 4(a).

[0032] One end of the inner wire 52a of the connecting wire 52 is connected to the clutch rod 31 (see FIG. 2), and the other end is hooked onto a notch 49 provided on the side of the rotating member 42 opposite the shaft 46. When the operator grips the clutch rod 31 together with the rear portion 30b of the handle rod 30, one end of the inner wire 52a is pulled, and the other end of the inner wire 52a pulls the rotating member 42. As a result, as shown in FIGS. 5(b) and 6(b), the rotating member 42 rotates clockwise about the shaft 46. On the other hand, when the operator releases the clutch rod 31, the rotating member 42 returns to its original position as shown in FIGS. 5(a) and 6(a) due to the biasing force of the torsion coil spring 44, which rotates the rotating member 42 about the shaft 46 and applies a force to the rotating member 42 pressing it against the columnar portion 48.

[0033] As shown in FIG. 5(b), when the rotating member 41 does not rotate and only the rotating member 42 rotates clockwise, the inner wire 50a of the lock wire 50 is slightly pulled. Similarly, as shown in FIG. 6(a), when the rotating member 41 rotates clockwise and the rotating member 42 does not rotate, the inner wire 50a of the lock wire 50 is slightly pulled. On the other hand, as shown in FIG. 6(b), when the rotating members 41 and 42 rotate clockwise, the inner wire 50a of the lock wire 50 is pulled more strongly than in the cases of FIGS. 5(b) and 6(a). Because one end of the inner wire 50a is connected to the arm 39c of the lock operation unit 34 (see FIGS. 7(a) and 7(b)), the inner wire 50a is pulled more strongly, which in turn pulls the arm 39c of the lock operation unit 34.

[0034] When the inner wire 50a of the lock wire 50 pulls strongly on the arm 39c of the lock operating unit 34, the lock operating unit 34 transitions from the state shown in FIG. 7(a) to the state shown in FIG. 7(b), thereby unlocking the gas spring 32. In this way, when the operator moves the shift lever 15 to the R (reverse) position and grips the clutch rod 31, the gas spring 32 switches from a locked state in which movement of the piston 75 is restricted to an unlocked state in which movement of the piston 75 is permitted. Note that when the inner wire 50a is pulled slightly as shown in FIGS. 5(b) and 6(a), the gas spring 32 is not unlocked.

[0035] Fig. 8 shows the handle rod 30 in a state before the clutch rod 31 is gripped. Fig. 9 shows the handle rod 30 in a state where the gearshift lever 15 is in a position other than R (reverse) and the clutch rod 31 is gripped. Fig. 10 shows the handle rod 30 in a state where the gearshift lever 15 is in R (reverse) and the clutch rod 31 is gripped. Fig. 11 shows the handle rod 30 in a state where the operator is pinched between the handle rod 30 and an obstacle behind the operator when the walk-behind working machine 100 is moving backward.

[0036] As shown in Figure 8, before the operator grips the clutch rod 31, the inner wire 35a of the clutch wire 35 and the inner wire 52a of the connecting wire 52, which connect to the clutch rod 31, are in a slack state. With the inner wire 35a slack, the clutch is in a disengaged state. With the inner wire 52a slack, the inner wire 50a of the lock wire 50 is not pulled or is only slightly pulled, regardless of the position of the shift lever 15, as shown in Figures 5(a) and 6(a), and the gas spring 32 is in a locked state.

[0037] As shown in Figure 9, when the shift lever 15 is in a position other than R (reverse) and the clutch rod 31 is gripped, the inner wire 35a of the clutch wire 35 is pulled by the clutch rod 31, putting the clutch in an engaged state, and the walk-behind work machine 100 moves forward, for example. Because the shift lever 15 is not in the R (reverse) position, as shown in Figure 5(b), the inner wire 52a of the connecting wire 52 is pulled, which slightly pulls the inner wire 50a of the lock wire 50, but the lock operating part 34 does not reach the unlocked position, so the gas spring 32 remains in the locked state.

[0038] As shown in Figure 10, when the shift lever 15 is in R (reverse) and the clutch rod 31 is gripped, the inner wire 35a of the clutch wire 35 is pulled by the clutch rod 31, the clutch is engaged, and the walk-behind work machine 100 moves backward. Because the shift lever 15 is in R (reverse) and the clutch rod 31 is gripped, the inner wire 50a of the lock wire 50 is pulled strongly, and the arm 39c of the lock operating unit 34 moves to a position that unlocks the gas spring 32, as shown in Figure 6(b).

[0039] If the walk-behind working machine 100 moves backward and the worker is caught between an obstacle behind the handle rod 30, the rear portion 30b of the handle rod 30 will rotate vertically downward (around the Y axis) relative to the front portion 30a, as shown in Fig. 11. At this time, the gas spring 32 generates a substantially constant resistance to the displacement, and therefore applies a predetermined amount of force to the rear portion 30b of the handle rod 30 to resist the rotation while allowing the rear portion 30b of the handle rod 30 to rotate. Therefore, the rear portion 30b of the handle rod 30 will rotate more slowly than if the gas spring 32 were not provided.

[0040] As the rear portion 30b of the handle rod 30 rotates relative to the front portion 30a, the inner wire 35a of the clutch wire 35 returns from the state in which it was pulled by the clutch rod 31 to the state before it was pulled. This disengages the clutch, interrupting the transmission of power from the engine 14 to the axle 12. This stops the rotation of the wheels 13, and the walk-behind working machine 100 stops. Furthermore, as the rear portion 30b of the handle rod 30 rotates relative to the front portion 30a, the inner wire 52a of the connection wire 52 also returns from the state in which it was pulled by the clutch rod 31 to the state before it was pulled. This causes the lock switching mechanism 33 to transition from the state shown in FIG. 6(b) to the state shown in FIG. 6(a). As a result of this transition to the state shown in FIG. 6(a), the arm 39c of the lock operating unit 34 transitions from the state shown in FIG. 7(b) to the state shown in FIG. 7(a), moving to a position where the gas spring 32 is locked. At this time, it is preferable that the tension of the inner wire 35a is reduced, causing the clutch to disengage and power to be cut off, and that the gas spring 32 be locked after the wheels 13 have stopped. In this way, the tension of the inner wire 35a is reduced, causing the gas spring 32 to be locked after the wheels 13 have stopped, and therefore the rear portion 30b of the handle rod 30 is fixed, allowing the worker to push the rear portion 30b of the handle rod 30 to move the walk-behind working machine 100 or to rely on the rear portion 30b of the handle rod 30 to escape from a pinched state.

[0041] In addition, in the first embodiment, the rotation of the rear portion 30b of the handlebar 30 is configured to stop the supply of power to the spark plug of the engine 14. This will be explained using Figures 12(a) and 12(b). Figures 12(a) and 12(b) show an enlarged view of area A in Figure 2. Figure 12(a) shows the state before the rear portion 30b of the handlebar 30 rotates, and Figure 12(b) shows the state after the rotation.

[0042] As shown in FIGS. 12(a) and 12(b), a switch 38 is attached to the front portion 30a of the handlebar 30. The switch 38 has a switching portion 38a and functions to cut off power to the spark plug when the switching portion 38a transitions from an unpressed state to a pressed state. In other words, the switch 38 is a kill switch that cuts off power to the spark plug of the engine 14. A contact member 54 is fixed near the switch 38 on the rear portion 30b of the handlebar 30. When the rear portion 30b of the handlebar 30 is not rotated relative to the front portion 30a, as shown in FIG. 10, the contact member 54 does not contact the switching portion 38a, as shown in FIG. 12(a). On the other hand, when the rear portion 30b of the handlebar 30 is rotated relative to the front portion 30a, as shown in FIG. 11, the contact member 54 presses the switching portion 38a, as shown in FIG. 12(b). In this manner, the rear portion 30b of the handle bar 30 rotates relative to the front portion 30a, and the switching portion 38a is pressed by the contact member 54, thereby stopping the engine 14. This also stops the rotation of the wheels 13, and the walk-behind working machine 100 stops.

[0043] The effects of the walk-behind working machine 100 according to the first embodiment will be described with reference to FIG. 13. FIG. 13 is a graph showing the change in the load (weight) applied to the worker after the worker begins to be pinched between the handle rod 30 and an obstacle behind the walk-behind working machine 100 when the walk-behind working machine 100 is moving backward. The horizontal axis of FIG. 13 represents time, and the vertical axis represents the load (weight) applied to the worker. The change in the load (weight) for the walk-behind working machine 100 according to the first embodiment is shown by a solid line, and the change in the load (weight) for a walk-behind working machine according to a comparative embodiment in which the handle rod does not bend is shown by a dashed line. A on the time axis indicates the time when the pinch occurs. B to E on the time axis indicate the time when the rear portion 30b of the handle rod 30 starts to rotate, C the time when the switch 38 is activated, D the time when the clutch is disengaged, and E the time when the rear portion 30b of the handle rod 30 finishes rotating, for the walk-behind working machine 100 according to the first embodiment.

[0044] As shown in Fig. 13, in a comparative walk-behind working machine in which the handle rod does not bend, the maximum load (weight) is applied to the worker shortly (approximately 1 second) after the worker begins to become pinched between the handle rod and an obstacle behind. In contrast, in the walk-behind working machine 100 according to the first embodiment, when a load equal to or greater than a predetermined level is applied to the handle rod 30 (time B), the rear portion 30b of the handle rod 30 rotates relative to the front portion 30a, and the gas spring 32 applies a force to the rear portion 30b that resists the rotation, so that a substantially constant load (weight) corresponding to the resistance of the gas spring 32 is applied to the worker. Therefore, compared to a walk-behind working machine according to the comparative embodiment in which the handle rod does not bend, the walk-behind working machine 100 according to the first embodiment reduces the load (weight) applied to the worker when the worker becomes pinched during reverse travel. With the load (weight) on the worker maintained low, the switch 38 (kill switch) is activated and the clutch wire 35 is loosened, disengaging the clutch in conjunction with the rotation of the rear portion 30b of the handlebar 30, thereby stopping the walk-behind working machine 100.

[0045] According to the first embodiment, the handlebar 30 has a front portion 30a (first portion) that is fixed at one end to the vehicle body 10 and extends rearward (toward the -X side) in the forward direction of the vehicle body 10, and a rear portion 30b (second portion) that is provided at the other end of the front portion 30a and is gripped by an operator, and the rear portion 30b is rotatable relative to the front portion 30a. The handlebar 30 is also provided with a gas spring 32 (restriction portion) that applies a force to the rear portion 30b of the handlebar 30 against the rotation while allowing the rear portion 30b to rotate, and a clutch wire 35 and a switch 38 (stop portion) that stop the rotation of the wheels 13 (traveling portion) by the engine 14 in conjunction with the rotation of the rear portion 30b of the handlebar 30. By providing gas spring 32, even if the operator is caught between an obstacle behind the operator and handle bar 30 when walking behind the work machine 100, a load corresponding to the resistance force generated when gas spring 32 contracts is applied to the operator, thereby reducing the load (weight) applied to the operator while still allowing the operator to operate the handle bar 30. Furthermore, because the rotation of wheels 13 by engine 14 stops in conjunction with the rotation of rear portion 30b of handle bar 30, the walk behind work machine 100 can be stopped with the load (weight) applied to the operator reduced.

[0046] Furthermore, in the first embodiment, the rear portion 30b of the handle rod 30 rotates vertically downward (around the Y axis) relative to the front portion 30a. If the operator is caught between an obstacle behind the operator and the rear portion 30b of the handle rod 30, the handle rod 30 will try to rotate so as to be pushed vertically upward about the axle 12 while hitting the operator's body and applying a horizontal force. In this case, the rear portion 30b of the handle rod 30 rotates vertically downward relative to the front portion 30a, thereby preventing the handle rod 30 from rotating so as to be pushed vertically upward. This prevents the operator's body from interfering with the rotation of the rear portion 30b due to an external force applied to the handle rod 30.

[0047] Furthermore, in the first embodiment, a lock operation unit 34 is provided for preventing rotation of the rear portion 30b of the handlebar 30. The lock operation unit 34 releases the prevention of rotation of the rear portion 30b of the handlebar 30 when the vehicle body 10 moves backward. This makes it possible to prevent the rear portion 30b of the handlebar 30 from rotating unintentionally when the vehicle body 10 moves forward, thereby ensuring the operability of the handlebar 30.

[0048] Furthermore, in the first embodiment, the lock operating unit 34 releases the prevention of rotation of the rear portion 30b of the handlebar 30 in conjunction with the operator operating the shift lever 15 (first switching unit) to move the vehicle body 10 in reverse and operating the clutch rod 31 (second switching unit) to establish a transmission state in which power is transmitted from the engine 14 to the axle 12. Since the vehicle body 10 starts moving in reverse when the shift lever 15 is operated to the R (reverse) position and the clutch rod 31 is gripped, releasing the prevention of rotation of the rear portion 30b of the handlebar 30 in conjunction with the operation of the shift lever 15 and the clutch rod 31 makes it possible to more reliably place the rear portion 30b of the handlebar 30 in a rotatable state when the vehicle body 10 moves in reverse.

[0049] In the first embodiment, the gas spring 32 is a restricting part that applies a force to the rear portion 30b of the handle rod 30 that resists rotation while allowing the rear portion 30b to rotate. As a result, as shown in Fig. 13, if the operator is caught between an obstacle behind the handle rod 30 and the handle rod 30 when the walk-behind working machine 100 is moving backward, a constant load (weight) corresponding to the resisting force when the gas spring 32 contracts is applied to the operator. This makes it easier to maintain a state in which the load (weight) applied to the operator does not exceed a certain value, and this time can be used to stop the rotation of the wheels 13 by the engine 14.

[0050] In the first embodiment, the restricting unit that applies a force resisting the rotation of the handle bar 30 is the gas spring 32, but other units such as a shock absorber may also be used. Even when the restricting unit is a shock absorber, a substantially constant resistance force is likely to be generated compared to a normal spring, even when the piston is displaced, just like the gas spring 32. Therefore, when the operator is caught between an obstacle behind the operator and the handle bar 30, the load (weight) applied to the operator is reduced and is likely to remain below a certain value.

[0051] Furthermore, in the first embodiment, one of the stopping parts that stops the rotation of the wheels 13 by the engine 14 in conjunction with the rotation of the rear portion 30b of the handlebar 30 is switch 38 (kill switch), which stops the supply of power to the spark plug of the engine 14. The operation of switch 38 (kill switch) can be achieved solely by mechanical action, eliminating the need for an additional electrical control circuit or the like, so the rotation of the wheels 13 can be stopped in conjunction with the rotation of the rear portion 30b of the handlebar 30 without the need to install a new battery or other electrical components in the walk-behind working machine 100.

[0052] Furthermore, in the first embodiment, one of the stopping parts that stops the rotation of the wheels 13 by the engine 14 in conjunction with the rotation of the rear portion 30b of the handlebar 30 is the clutch wire 35 connected to the clutch rod 31, which disengages the clutch between the engine 14 and the axle 12. This can be achieved using only a mechanical operation and does not require the use of an additional electrical control circuit, so the rotation of the wheels 13 can be stopped in conjunction with the rotation of the rear portion 30b of the handlebar 30 without the need to install a new battery or other electrical components in the walk-behind work machine 100.

[0053] Furthermore, in the first embodiment, even when the operator is gripping the clutch rod 31 to engage the clutch, the clutch is disengaged in conjunction with the rotation of the rear portion 30b of the handle rod 30. As described above, if the operator is pinched between an obstacle behind the operator and the rear portion 30b of the handle rod 30, the handle rod 30 will try to rotate vertically upward about the axle 12 while hitting the operator's body and applying a horizontal force. In such a case, the operator may not have enough time to release the clutch rod 31 because the handle rod 30 presses against the area near the chest and abdomen. However, by disengaging the clutch in conjunction with the rotation of the rear portion 30b of the handle rod 30 even when the operator is gripping the clutch rod 31 and the clutch is engaged, the rotation of the wheels 13 can be stopped even when there is no time to release the clutch rod 31. Furthermore, if the operator is caught between an obstacle behind the operator and the handlebar 30, as described above, the handlebar 30 may push up against the operator's chest and abdomen, causing the clutch rod 31 to remain in a lowered position even after the operator releases the handlebar 30. Even in such a case, the rotation of the wheels 13 can be stopped in conjunction with the rotation of the rear portion 30b of the handlebar 30.

[0054] Furthermore, in the first embodiment, in conjunction with the rotation of the rear portion 30b of the handlebar 30, the power supply to the spark plug of the engine 14 is stopped and the clutch between the engine 14 and the axle 12 is disengaged. This makes it possible to more reliably stop the rotation of the wheels 13 if the operator is caught between an obstacle behind the operator and the handlebar 30.

[0055] In the first embodiment, it is also possible that, in conjunction with the rotation of the rear portion 30b of the handlebar 30, either the power supply to the spark plug of the engine 14 is stopped or the clutch between the engine 14 and the axle 12 is disengaged.

[0056] In the first embodiment, when the worker is caught between a rear obstacle and the handlebar 30 and the rear portion 30b of the handlebar 30 rotates relative to the front portion 30a, causing the wheels 13 to stop, the gas spring 32 may remain in the unlocked state without transitioning to the locked state. In this case, the rear portion 30b of the handlebar 30 moves, allowing the worker caught between the obstacle and the handlebar 30 to move the rear portion 30b of the handlebar 30 and escape.

[0057] In the first embodiment, the structure of the lock switching mechanism 33 shown in Figures 5(a) to 6(b) is an example, and other structures may be used as long as the functions described in the claims can be realized.

[0058] Second Embodiment FIG. 14 shows a walk-behind working machine 200 according to the second embodiment, viewed obliquely from above. As shown in FIG. 14, the walk-behind working machine 200 has a handle rod 60 provided on the -X side of the vehicle body 10. The handle rod 60 has one end fixed to the vehicle body 10, a front section 60a extending rearward in the forward direction of the vehicle body 10, and a rear section 60b attached to the other end of the front section 60a and gripped by the operator. The rear section 60b is rotatable vertically downward (around the Y axis) relative to the front section 60a. The rear section 60b has a U-shaped, two-handle structure with left and right grips for the operator to grip. A clutch rod 61 is provided on one of the left and right grips. Furthermore, the switch 38 shown in FIGS. 12(a) and 12(b) of the first embodiment is provided in area A. The rest of the configuration is the same as that of the walk-behind working machine 100 according to the first embodiment, and therefore a description thereof will be omitted.

[0059] In the second embodiment, handle rod 60 also has a front portion 60a (first portion) that is fixed at one end to vehicle body 10 and extends rearward in the forward direction (-X side) of vehicle body 10, and a rear portion 60b (second portion) that is provided at the other end of front portion 60a and is gripped by the operator, with rear portion 60b being rotatable relative to front portion 60a. Walk-behind working machine 200 is also provided with gas spring 32 (restriction portion) that applies a force to rear portion 60b of handle rod 60 that resists rotation while allowing the rear portion 60b to rotate, and clutch wire 35 and switch 38 (stop portion) that stop rotation of wheels 13 caused by engine 14 in conjunction with the rotation of rear portion 60b of handle rod 60. As a result, even if the worker is caught between an obstacle behind him and the handle rod 60 when the walk-behind working machine 200 is moving backward, the worker will be subjected to a load corresponding to the resistance force when the gas spring 32 contracts, thereby reducing the load (weight) on the worker while maintaining the worker's ability to operate the handle rod 30.

[0060] Third Embodiment FIG. 16 shows a walk-behind working machine 300 according to the third embodiment as viewed from the +Z direction. FIGS. 17(a) and 17(b) are enlarged views of the vicinity of the display panel 17 in the third embodiment. FIG. 17(a) shows the state in which the gearshift lever 15 is in the N (neutral) position, and FIG. 17(b) shows the state in which the gearshift lever 15 is in the R (reverse) position. As shown in FIGS. 16 to 17(b), the walk-behind working machine 300 does not have a lock switching mechanism 33, and therefore does not have connecting wires 51 and 52. As in the first embodiment, one end of the outer cable 50b of the lock wire 50 is attached to the fixing portion 39d of the lock operating unit 34 as shown in FIGS. 7(a) and 7(b). As in the first embodiment, one end of the inner wire 50a is connected to the arm 39c of the lock operating unit 34 as shown in FIGS. 7(a) and 7(b). Meanwhile, unlike the first embodiment, the other end of outer cable 50b of lock wire 50 is attached to fixed portion 17a fixed to indicator plate 17 provided near the lower end of shift lever 15, on the opposite side of R (reverse) with respect to shift lever 15. Unlike the first embodiment, the other end of inner wire 50a is connected to moving member 53 provided near shift lever 15. The rest of the configuration is the same as that of walk-behind working machine 100 of the first embodiment, so description thereof will be omitted.

[0061] When the shift lever 15 moves from the N (neutral) position to the R (reverse) position, a portion 53a of the moving member 53 is pushed by the shift lever 15 and moves. As a result, the inner wire 50a of the lock wire 50 is pulled strongly by the moving member 53. As the inner wire 50a is pulled strongly by the moving member 53, the arm 39c of the lock operating unit 34 is pulled, and the lock operating unit 34 transitions from the state shown in FIG. 7(a) to the state shown in FIG. 7(b). As a result, the gas spring 32 enters an unlocked state.

[0062] Thus, according to the third embodiment, the lock operating unit 34 releases the prevention of rotation of the rear portion 30b of the handle rod 30 in conjunction with the operator operating the shift lever 15 (first switching unit) so that the vehicle body 10 moves backward. Since the walk-behind working machine 100 is able to move backward when the shift lever 15 is operated to the R (reverse) position, by releasing the prevention of rotation of the rear portion 30b of the handle rod 30 in conjunction with the operation of the shift lever 15, it is possible to more reliably put the rear portion 30b of the handle rod 30 into a state where it can rotate when the vehicle body 10 moves backward.

[0063] Fourth Embodiment In the first to third embodiments described above, the gas spring 32 itself is provided with a locking function, as shown in Figures 15(a) and 15(b), but in this fourth embodiment, a case will be described in which a gas spring 32a without a locking function is used. Since everything except the gas spring 32a and the lock operating unit 34a is the same as in the first embodiment described above, the gas spring 32a and the lock operating unit 34a will be mainly described.

[0064] 15(a) and 15(b), the gas spring 32a differs in that it is not provided with a valve 77 or a push rod 78. Therefore, oil can always flow through the orifice hole 76.

[0065] Figure 18 shows the handle rod 30 of the walk-behind working machine of the fourth embodiment in a state before the clutch rod 31 is gripped. Figure 19(a) is an enlarged view of area A in Figure 18, and Figure 19(b) is an enlarged view of the vicinity of the link mechanism 90 in Figure 19(a) as viewed from direction A. As shown in Figure 18, the lock operating unit 34a includes a link mechanism 80 and a link mechanism 90.

[0066] As shown in FIG. 19( a), link mechanism 80 includes links 81, 82, and 83. One end of link 81 is rotatably connected to the tip of piston rod 74 of gas spring 32a by joint 84. One end of link 82 is rotatably connected to the tip of cylinder 70 of gas spring 32a by joint 85. Link 83 has a protrusion 87 at one end. Protrusion 87 is inserted into a guide groove 89 of a rail portion 88 fixed to front portion 30a of handlebar 30. The other end of link 81, the other end of link 82, and the other end of link 83 are rotatably connected to one another by joint 86. When gas spring 32a is extended, links 81 and 82 are preferably bent in a dogleg shape toward link 83 so that joint 86 moves toward link 83 when gas spring 32a contracts. In order to allow links 81 and 82 to bend in an L-shape, the total length of links 81 and 82 may be made longer than the length of piston rod 74, or the position of joint 86 may be made so that links 81 and 82 bend in an L-shape when protrusion 87 of link 83 abuts against the lower end of guide groove 89.

[0067] The link mechanism 90 includes links 91, 92, and 93. Link 91 is L-shaped, and a corner of the L is rotatably connected to rail portion 88 by a joint 94. An inner wire 50a of the lock wire 50 is connected to a joint 95 rotatably connected to one end of link 91. The other end of link 91 is rotatably connected to one end of link 92 by a joint 96. The other end of link 92 is rotatably connected to one end of link 93 by a joint 97. The other end of link 93 is rotatably connected to rail portion 88 by a joint 98. Link 93 is provided with a protruding blocking portion 99 that prevents protrusion 87 of link 93 from moving in guide groove 89 of rail portion 88.

[0068] 19(b), links 91, 92, and 93 are provided in pairs so as to sandwich the rail portion 88. A joint 95 is rotatably connected to the tip end of the pair of links 91, and an inner wire 50a of the lock wire 50 is connected to this joint 95.

[0069] Before the operator grips the clutch rod 31, the inner wire 52a of the connecting wire 52 is not pulled by the clutch rod 31, and therefore the inner wire 50a of the lock wire 50 is not pulled or is only slightly pulled, as shown in Figures 5(a) and 6(a). In this case, as shown in Figure 19(a), the blocking portion 99 of the link 93 is in a position that prevents the protrusion 87 of the link 83 from moving in the guide groove 89 of the rail portion 88. Therefore, the links 81, 82, and 83 cannot move, and the gas spring 32a is in a locked state where it cannot contract.

[0070] Figure 20 shows the handlebar 30 of the walk-behind working machine of the fourth embodiment with the shift lever 15 in R (reverse) and the clutch rod 31 gripped. Figure 21 is an enlarged view of area A in Figure 20. As shown in Figures 20 and 21, when the shift lever 15 is in R (reverse) and the clutch rod 31 is gripped, the inner wire 50a of the lock wire 50 is pulled strongly, as shown in Figure 6(b). This causes the lock operating part 34a to operate to unlock the gas spring 32a. The operation of the lock operating part 34a will be described in detail below.

[0071] When the inner wire 50a of the lock wire 50 is pulled strongly, as shown in FIG. 21 , the link 91 rotates counterclockwise around the joint 94, one end of the link 91 moves closer to the lock wire 50, and the other end of the link 91 moves so as to lift up one end of the link 92. As a result, the link 92 rotates counterclockwise around the joint 96, and the other end of the link 92 moves so as to lift up one end of the link 93. As a result, the link 93 rotates clockwise around the joint 98. As a result, the blocking portion 99 provided on the link 93 moves to a position away from the guide groove 89 of the rail portion 88. This allows the protrusion 87 of the link 83 to move in the guide groove 89. Therefore, the links 81, 82, and 83 can move in conjunction with one another, and the gas spring 32a enters an unlocked state in which it can contract.

[0072] Fig. 22 shows the handle rod 30 of the walk-behind working machine of the fourth embodiment in a state in which the operator is pinched between the handle rod 30 and an obstacle behind the operator when the walk-behind working machine is moving backward. Fig. 23 is an enlarged view of area A in Fig. 22. As shown in Figs. 22 and 23, when the operator is pinched between the obstacle behind the operator and the handle rod 30, the gas spring 32a is in an unlocked state and is able to contract, so that the rear portion 30b of the handle rod 30 rotates vertically downward (around the Y axis) relative to the front portion 30a. That is, the links 81 and 82 rotate about the joints 84 and 85 so as to push up the link 83, and the protrusion 87 of the link 83 moves along the guide groove 89, causing the gas spring 32a to contract, and the rear portion 30b of the handle rod 30 rotates vertically downward (around the Y axis) relative to the front portion 30a. Therefore, the gas spring 32a applies a predetermined force to the rear portion 30b of the handle bar 30 against rotation while allowing the rear portion 30b to rotate, so that the rear portion 30b of the handle bar 30 rotates slowly.

[0073] As in the first embodiment, the fourth embodiment also includes a gas spring 32a that applies a force to the rear portion 30b of the handle rod 30 that resists rotation while allowing the rear portion 30b to rotate. Therefore, even if the operator is pinched between the handle rod 30 and an obstacle behind the operator when the walk-behind working machine is moving backward, the operator will be subjected to a load corresponding to the resisting force when the gas spring 32a contracts, and the load (weight) applied to the operator can be reduced while maintaining the operator's ability to operate the handle rod 30.

[0074] In addition, in the fourth embodiment, a lock operation unit 34a including a link mechanism 80 and a link mechanism 90 is provided to prevent rotation of the rear portion 30b of the handle rod 30. By providing such a lock operation unit 34a, even if the gas spring 32a itself does not have a locking function, it is possible to set the gas spring 32a to a locked state in which contraction is suppressed.

[0075] [Modification of the lock operation part] The lock operation unit 34b according to the modified example differs from the lock operation unit 34a in that it is provided with a ball plunger 62 that prevents the gas spring 32a from starting to contract until a load greater than a preset initial reaction force is applied to the gas spring 32a, even when the gas spring 32a is in the unlocked state. The following description will focus on the differences from the lock operation unit 34a.

[0076] 24(a) and 24(b) are views showing a modified lock operation unit 34b in a state before the clutch rod 31 is gripped. FIG. 24(b) shows a cross section passing through the ball plunger 62 in FIG. 24(a). Note that in FIG. 24(b), the guide groove 89 is shown with a dotted line for reference (the same applies to similar figures below). As shown in FIGS. 24(a) and 24(b), the ball plunger 62 provided in the lock operation unit 34b includes a coil spring 64 built into a main body 63 and a ball 65 biased by the coil spring 64. The link 83 is provided with a recess 66a having a width approximately equal to the diameter of the ball 65 and a depth shallower than the diameter of the ball 65, and a recess 66b having a depth approximately equal to the recess 66a and longer than the recess 66a in the direction in which the link 83 moves along the guide groove 89. Before the clutch rod 31 is gripped, the ball 65 of the ball plunger 62 is fitted into the recess 66a and is urged toward the recess 66a by the coil spring 64.

[0077] 25(a) and 25(b) are views showing a modified lock operating portion 34b in a state where the shift lever 15 is in R (reverse) and the clutch rod 31 is gripped. FIG. 25(b) shows a cross section passing through the ball plunger 62 in FIG. 25(a). As shown in FIGS. 25(a) and 25(b), when the shift lever 15 is in R (reverse) and the clutch rod 31 is gripped, the blocking portion 99 of the link 93 separates from the guide groove 89 of the rail portion 88, allowing the protrusion 87 of the link 83 to move along the guide groove 89. Even in this case, the link 83 will not move unless the force sliding the link 83 along the guide groove 89 is greater than or equal to the force expelling the ball 65 of the ball plunger 62 from the recess 66a. 22, in order for the rear portion 30b of the handle rod 30 to begin to rotate relative to the front portion 30a, a load greater than the force required to eject the ball 65 of the ball plunger 62 from the recess 66a must be applied to the rear portion 30b of the handle rod 30. The load required to eject the ball 65 from the recess 66a is made greater than the initial reaction force of the gas spring 32a by adjusting the biasing force of the coil spring 64 and / or the depth of the recess 66a.

[0078] 26(a) and 26(b) show the lock operating device 34b according to the modified example immediately after the ball 65 of the ball plunger 62 has been released from the recess 66a, and FIGS. 27(a) and 27(b) show the lock operating device 34b according to the modified example shortly after the ball 65 has been released from the recess 66a. FIG. 26(b) shows a cross section passing through the ball plunger 62 in FIG. 26(a), and FIG. 27(b) shows a cross section passing through the ball plunger 62 in FIG. 27(a). As shown in FIGS. 26(a) to 27(b), when a load is applied to the rear portion 30b of the handle bar 30 such that the ball 65 of the ball plunger 62 is released from the recess 66a, the ball 65 is released from the recess 66a. As a result, as shown in FIG. 23, the links 81, 82, and 83 move in conjunction with one another, and the gas spring 32a begins to compress. 27(b), ball 65 moves out of recess 66a and then into recess 66b. This weakens the force of coil spring 64 pressing ball 65, allowing smoother movement of ball 65. Note that recess 66b does not necessarily have to be provided.

[0079] 28(a) and 28(b) are views showing a modified lock operating unit 34b in a state where the gas spring 32a is greatly compressed. Fig. 28(b) shows a cross section passing through the ball plunger 62 in Fig. 28(a). As shown in Figs. 28(a) and 28(b), when the ball 65 of the ball plunger 62 comes out of the recess 66a, the gas spring 32a compresses while being subjected to a resistance force, and as a result, the protrusion 87 of the link 83 moves along the guide groove 89 of the rail portion 88.

[0080] According to the modified lock operating unit 34b, the load required for the gas spring 32a to start compressing can be adjusted by the ball plunger 62. For example, by adjusting the ball plunger 62, it is possible to make the ball plunger 62 come out of the recess 66a when a load greater than the initial reaction force of the gas spring 32a is applied to the rear portion 30b of the handle rod 30 when the walk-behind working machine is moving backward. This causes the gas spring 32a to start compressing, and the prevention of rotation of the rear portion 30b of the handle rod 30 is released.

[0081] For example, if the ball plunger 62 is not provided, the gas spring 32a begins to compress when a load greater than the initial reaction force of the gas spring 32a is applied. In this case, the initial reaction force of the gas spring 32a is set to a magnitude that is less likely to injure an operator if they are pinched between an obstacle behind them and the rear portion 30b of the handlebar 30, and that does not impair operability of the handlebar 30 when moving backward. However, in this case, the initial reaction force of the gas spring 32a becomes somewhat large. Because the reaction force of the gas spring 32a during compression is greater than the initial reaction force, there is a risk of a large load being imposed on an operator who is pinched between an obstacle behind them and the rear portion 30b of the handlebar 30. In contrast, by providing the ball plunger 62, the load at which the gas spring 32a begins to compress can be adjusted by the ball plunger 62, allowing the initial reaction force of the gas spring 32a to be freely set. Therefore, by setting the initial reaction force of the gas spring 32a low and preventing the reaction force of the gas spring 32a from becoming too high during compression, the load imposed on the operator can be prevented from becoming too large. Furthermore, by appropriately adjusting the ball plunger 62, even if the initial reaction force of the gas spring 32a is set low, it is possible to prevent the operability of the handlebar 30 from becoming worse.

[0082] In the first to third embodiments, a ball plunger may be provided to prevent the gas spring 32 from starting to contract until a load greater than a preset initial reaction force is applied to the gas spring 32. For example, a configuration may be adopted in which a member similar to the contact member 54 shown in Fig. 12 is provided adjacent to both the front portion 30a and the rear portion 30b of the handlebar 30, a ball plunger is provided on a member provided on either the front portion 30a or the rear portion 30b, and the ball plunger is pressed against a member provided on the other portion, with a recess provided in the other portion.

[0083] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims. [Explanation of symbols]

[0084] 10. Body 11 Working section 12 Axle (drive axle) 13 Wheels (running part) 14 Engine (drive unit) 15 Shift lever (first switching part) 16 tiller tines 17 Display board 17a Fixed part 17b Stopper 18 Groove 30, 60 Handle rod 30a, 60a Front part of the handlebar (first part) 30b, 60b Rear part of the handlebar (second part) 31, 61 Clutch rod (second switching part) 32, 32a Gas spring (restriction part) 33 Lock switching mechanism 34, 34a, 34b Lock operation part 35 Clutch wire (stop part) 35a inner wire 35b outer cable 36, 37 Fixing member 38 Switch (stop) 38a Switching section 39a Flange 39b Rotation axis 39c Arm 39d Fixed part 40 Plate-shaped member Area 40a-40d 41, 42 Rotating members 43, 44 Torsion coil spring 45th and 46th axes 47 Cutout 48 Columnar part 49 Notch 50 Lock Wire 50a inner wire 50b outer cable 51, 52 Connecting wires 51a, 52a inner wire 51b, 52b outer cable 53 Moving parts 54 Contact member 62 Ball plunger 63 Main body 64 Coil spring 65 balls 66a, 66b depressions 70 cylinders 72, 73 space 74 Piston rod 75 pistons 76 Orifice 77 Valve 78 Push rod 80 Link mechanism 81, 82, 83 Links 84, 85, 86 joints 87 Protrusion 88 Rail section 89 Guide groove 90 Link mechanism 91, 92, 93 Links 94, 95, 96, 97, 98 Joints 99 Blocking part 100, 200, 300 Walk-behind Work Machine

Claims

1. a vehicle body having a traveling unit that travels using power from a drive unit and performs a predetermined task; a handlebar having a first portion fixed at one end to the vehicle body and extending rearward in the forward movement direction of the vehicle body, and a second portion provided at the other end of the first portion and gripped by an operator, the second portion rotating relative to the first portion; a restricting portion that applies a force to the second portion against the rotation while allowing the second portion to rotate; a stopper that stops the traveling of the traveling unit in conjunction with the rotation of the second portion; a lock operation portion for preventing the second portion from rotating, The lock operation unit releases the prevention of rotation of the second part when the vehicle body is moving backward.

2. a first switching unit that is operated by the operator to switch the traveling direction of the vehicle body between forward and reverse; 2. The walk-behind working machine according to claim 1, wherein the lock operating unit releases the prevention of rotation of the second part in conjunction with the operator operating the first switching unit so as to move the vehicle body backward.

3. a first switching unit operated by the operator to switch the traveling direction of the vehicle body between forward and reverse; a second switching unit operated by the operator to switch between a transmission state in which the power is transmitted from the drive unit to the traveling unit and a cut-off state in which the power is cut off, 2. The walk-behind working machine according to claim 1, wherein the lock operating unit releases the prevention of rotation of the second part in conjunction with the operator operating the first switching unit to move the vehicle body backward and operating the second switching unit to enter the transmission state.

4. A vehicle body having a running part that runs using the power of a drive part and performs a predetermined task; a handlebar having a first portion fixed at one end to the vehicle body and extending rearward in the forward movement direction of the vehicle body, and a second portion provided at the other end of the first portion and gripped by an operator, the second portion rotating relative to the first portion; a restricting portion that applies a force to the second portion against the rotation while allowing the second portion to rotate; a stopper that stops the traveling of the traveling unit in conjunction with the rotation of the second portion; a lock operation portion for preventing the second portion from rotating, The lock operation unit releases the prevention of rotation of the second part when a load greater than the initial reaction force of the regulating unit is applied to the second part when the vehicle body is moving backward.

5. A vehicle body having a running part that runs using the power of a drive part and performs a predetermined task; a handlebar having a first portion fixed at one end to the vehicle body and extending rearward in the forward movement direction of the vehicle body, and a second portion provided at the other end of the first portion and gripped by an operator, the second portion rotating relative to the first portion; a restricting portion that applies a force to the second portion against the rotation while allowing the second portion to rotate; a stopper that stops the travel of the travel unit in conjunction with the rotation of the second part, The walk-behind working machine, wherein the regulating portion is a gas spring or a shock absorber.

6. A vehicle body having a running part that runs using the power of a drive part and performs a predetermined task; a handlebar having a first portion fixed at one end to the vehicle body and extending rearward in the forward movement direction of the vehicle body, and a second portion provided at the other end of the first portion and gripped by an operator, the second portion rotating relative to the first portion; a restricting portion that applies a force to the second portion against the rotation while allowing the second portion to rotate; a stopper that stops the travel of the travel unit in conjunction with the rotation of the second part, the drive unit is a motor, The stop unit stops supplying power to an ignition plug of the engine in response to rotation of the second part.

7. The walk-behind working machine according to claim 1 , wherein the stopping unit disengages a clutch that transmits power from the drive unit to the travel unit in conjunction with the rotation of the second part.

8. A vehicle body having a running part that runs using the power of a drive part and performs a predetermined task; a handlebar having a first portion fixed at one end to the vehicle body and extending rearward in the forward movement direction of the vehicle body, and a second portion provided at the other end of the first portion and gripped by an operator, the second portion rotating relative to the first portion; a restricting portion that applies a force to the second portion against the rotation while allowing the second portion to rotate; a stopper that stops the travel of the travel unit in conjunction with the rotation of the second part, the drive unit is a motor, The stop unit, in conjunction with the rotation of the second part, stops the supply of power to an ignition plug of the engine and disengages a clutch that transmits power from the engine to the traveling unit.

9. 9. The walk-behind working machine according to claim 7, wherein the stopping unit disengages the clutch in conjunction with the rotation of the second part, even when the operator is performing an operation to engage the clutch.

10. The walk-behind work machine according to claim 1 , wherein the second portion rotates vertically downward relative to the first portion.

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