Walk-behind work machine

Abstract

To provide a walking type work machine capable of reducing a burden (load) applied to an operator while maintaining operability for a handle lever of the operator even when the operator is sandwiched between an obstacle behind and the handle lever.SOLUTION: A walking type work machine 500 includes: a vehicle body 10 having wheels 13 for traveling with the use of power of an engine 14 for executing predetermined work; a handle lever 30 having a front part 31 extending behind the vehicle body 10, one end of which is fixed to the vehicle body 10, and a rear part 32 provided to the other end of the front part 31 for being gripped by an operator, in which the rear part 32 can be slidably moved in a forward direction of the vehicle body 10 with respect to the front part 31; a gas spring 50 for imparting force against the sliding movement to the rear part 32 while permitting the sliding movement of the rear part 32; and a clutch wire 41 and a switch 45 for stopping the wheels 13 in conjunction with the sliding movement of the rear part 32.SELECTED DRAWING: Figure 1

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 attached to the rear of the machine body and performs work using a working unit attached to the machine body. There are times when the operator reverses the walk-behind working machine 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 reversed.

[0003] The following configurations are known as safety devices. For example, a configuration is known in which a sliding mechanism is provided on the handlebar, and the engine is stopped in conjunction with the sliding of the sliding mechanism when a load greater than a predetermined value is applied to the handlebar (see, for example, Patent Document 1). For example, a configuration is known in which a clamping rod is provided that protrudes rearward from the rear end of the handlebar, and a holding means is provided that holds the deadman clutch in the "on" state, and the clamping rod is movable back and forth, so that the holding of the holding means can be released by the forward movement of the clamping rod (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 09-109725 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-88769 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have newly discovered that when a worker is caught between an obstacle behind the walk-behind work machine and the handlebar while the machine is moving backward, the greatest force is applied to the worker in a short time after the worker is caught. Even if the technologies disclosed in Patent Documents 1 and 2 allow the engine to stop or the clutch to be disengaged when a load greater than a predetermined level is applied to the handlebar, it is difficult to instantly stop the machine from moving backward after the worker is caught between the obstacle and the handlebar. 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 an obstacle behind the worker and the handlebar. [Means for solving the problem]

[0007] 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 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 allows the second part to slide forward of the vehicle body relative to the first part, a regulating part that applies a force to the second part that resists the sliding movement while allowing the sliding movement of the second part, a stop part that stops the running of the running part in conjunction with the sliding movement of the second part, and a lock operating part for preventing the sliding movement of the second part, and the lock operating part releases the prevention of the sliding movement of the second part 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 that is fixed at one end to the vehicle body and extends rearward 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 allows the second part to slide forward of the vehicle body relative to the first part, a regulating part that applies a force to the second part that resists the sliding movement while allowing the sliding movement of the second part, a stop part that stops the running of the running part in conjunction with the sliding movement of the second part, and a lock operating part for preventing the sliding movement of the second part, wherein the lock operating part releases the prevention of the sliding movement 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. [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 an obstacle behind the worker and the handlebar. [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 cross-sectional views showing the gas spring according to the first embodiment. [Figure 5] 5(a) and 5(b) are diagrams showing the vicinity of the gas spring in the first embodiment. [Figure 6] 6(a) and 6(b) are diagrams showing the vicinity of the gearshift lever in the first embodiment. [Figure 7] FIG. 7 is a diagram showing the handlebar viewed from diagonally above with the gearshift lever in the N (neutral) position and the clutch lever not being gripped. [Figure 8] FIG. 8 is a diagram showing the handlebar viewed from the +Y direction with the gearshift lever in the N (neutral) position and the clutch lever not being gripped. [Figure 9] FIG. 9 is a diagram showing the handlebar viewed from diagonally above with the gearshift lever in R (reverse) and the clutch lever gripped. [Figure 10] FIG. 10 is a diagram showing the handlebar viewed from the +Y direction with the gearshift lever in R (reverse) and the clutch lever gripped. [Figure 11] FIG. 11 is a diagram showing the handlebar viewed from diagonally above, in which the operator is caught between the handlebar and an obstacle behind the operator when the walk-behind working machine is moving backward. [Figure 12] FIG. 12 is a diagram showing the handlebar viewed from the +Y direction in a state where the operator is caught between the handlebar and an obstacle behind the operator when the walk-behind working machine is moving backward. [Figure 13] 13(a) is an enlarged view of region A in FIG. 10, and FIG. 13(b) is an enlarged view of region A in FIG. [Figure 14] FIG. 14 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 15] FIG. 15 is a diagram showing the walk-behind working machine according to the second embodiment as viewed from the +Z direction. [Figure 16] 16(a) and 16(b) are diagrams showing the vicinity of the gearshift lever in the second embodiment. [Figure 17] 17(a) and 17(b) are diagrams showing the lock switching mechanism when the gearshift lever is set to a position other than R (reverse). [Figure 18] 18(a) and 18(b) are diagrams showing the lock switching mechanism when the gearshift lever is set to R (reverse). [Figure 19] FIG. 19 is a view showing the lock switching mechanism after the rear portion of the handle bar has slid. [Figure 20] FIG. 20 is a diagram showing the walk-behind working machine according to the third embodiment as viewed obliquely from above. [Figure 21] Figure 21(a) is a diagram showing the vicinity of the lock operation part when the shift lever is in a position other than R (reverse) in the fourth embodiment, and Figure 21(b) is an enlarged view of area A in Figure 21(a). [Figure 22] FIG. 22(a) is a diagram showing the vicinity of the lock operation portion when the gearshift lever is in R (reverse) in the fourth embodiment, and FIG. 22(b) is an enlarged view of area A in FIG. 22(a). [Figure 23] Figure 23(a) is a diagram showing the vicinity of the lock operating part when the worker is pinched between an obstacle behind him and the handlebar, causing the rear part of the handlebar to slide relative to the front part in the fourth embodiment, and Figure 23(b) is an enlarged view of area A in Figure 23(a). [Figure 24] 24(a) to 24(c) are diagrams showing the vicinity of the lock operation portion in the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment A walk-behind working machine 500 according to a first embodiment will be described below with reference to FIGS. 1 to 14. The walk-behind working machine 500 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 500 may be a 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 500 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 500. The forward direction of the walk-behind working machine 500 is the +X direction, the backward direction is the -X direction, and of the directions (left and right directions) perpendicular to the X axis in a horizontal plane, the left direction when facing the +X direction is the +Y direction, the right direction is the -Y direction, the vertical upward direction is the +Z direction, and the downward direction is the -Z direction. Figure 1 shows the walk-behind working machine 500 as seen from the +Y direction, Figure 2 shows the walk-behind working machine 500 as seen from the +Z direction, and Figure 3 shows the walk-behind working machine 500 as seen from diagonally above.

[0012] 1 to 3, the walk-behind work machine 500 includes a body 10, a working unit 11 provided at the rear of the body 10, 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, an engine 14 provided on the body 10, a gearshift lever 15 provided on the body 10, and a handle bar 30 provided at the rear of the body 10 and held by an operator. The engine 14 is a drive unit that rotates the wheels 13 and the tiller tines 16 of the working unit 11. In addition to the engine 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 tines 16. The tines 16 rotate using power from a motor 14. The working unit 11 is raised and lowered by the rotation of the wheels 13 when the operator moves the handlebar 30 up and down. When tilling, the operator lowers the working unit 11 downward, with the tines 16 inserted into the soil. For safety reasons, the walk-behind working machine 500 is designed so that the tines 16 do not operate when the machine is reversing. Alternatively, the walk-behind working machine 500 is designed so that the tines 16 cannot be moved backward when the tines 16 are operating.

[0014] The wheels 13 rotate by power supplied from the engine 14 to the axles 12 via a clutch (not shown). The wheels 13 are the running parts that propel the vehicle body 10. The clutch is provided between the engine 14 and the wheels 13, and mechanically transmits and cuts off 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 operation mode by operating the speed change lever 15 along the groove 18 (see Figures 6(a) and 6(b)) provided in the display panel 17, and can move the walk-behind working machine 500 forward or backward.

[0016] The handlebar 30 has a front portion 31 that is fixed at one end to the vehicle body 10 and extends rearward from the vehicle body 10, and a rear portion 32 that is attached to the other end of the front portion 31 and is gripped by an operator. A cylindrical mounting member 33 for mounting the rear portion 32 to the front portion 31 is provided at a location on the front portion 31 that is located on the -X direction side of the vehicle body 10. Two mounting members 33 are provided symmetrically with respect to the center of the rear portion 32 in the Y axis direction. The rear portion 32 is attached to the front portion 31 so that it can slide in the X axis direction relative to the front portion 31 by inserting two protruding guide portions 34, which are provided symmetrically with respect to the center in the Y axis direction, into the cylindrical mounting member 33.

[0017] The handlebar 30 is provided with a clutch rod 40 and a gas spring 50. Although not shown, the handlebar 30 is also provided with an engine switch.

[0018] The clutch rod 40 is disposed above the rear portion 32 of the handle rod 30 so that the operator can grasp it together with the rear portion 32 of the handle rod 30. The clutch rod 40 is attached to the rear portion 32 of the handle rod 30 and is rotatable around a rotation axis provided below the rear portion 32 of the handle rod 30.

[0019] An inner wire 41a (an inner portion covered by an outer cable 41b) of a clutch wire 41 is connected to the clutch rod 40. The inner wire 41a is connected to the clutch rod 40 on the opposite side of the rear portion 32 of the handle rod 30 from the rotation axis of the clutch rod 40, which is provided below the rear portion 32 of the handle rod 30. The end of the outer cable 41b of the clutch wire 41 is attached at a position such that the distance from the end of the outer cable 41b to the attachment position of the inner wire 41a to the clutch rod 40 becomes small when the operator releases the clutch rod 40 or when the rear portion 32 of the handle rod 30 slides in the +X direction relative to the front portion 31, as described below. For example, the end of the outer cable 41b is attached to a fixing portion 35 (see FIG. 2) that is fixed to an attachment member 33 provided on the front portion 31 of the handle rod 30. When the operator grips the clutch rod 40 together with the rear portion 32 of the handlebar 30, the inner wire 41a of the clutch wire 41 is pulled, the clutch is engaged, and power is transmitted from the engine 14 to the axle 12 (transmission state is established). On the other hand, when the operator releases the clutch rod 40, the inner wire 41a returns to its original state, the clutch is disengaged, and the transmission of power from the engine 14 to the axle 12 is interrupted (interruption state is established). In this way, the operator can control the travel of the walk-behind working machine 500 by operating the clutch rod 40.

[0020] The gas spring 50 is a spring that uses the reaction force of compressed gas and is equipped with a locking mechanism that switches between a locked state (a state where it cannot expand or contract) and an unlocked state (a state where it can expand or contract). FIGS. 4(a) and 4(b) show cross-sectional views of the gas spring 50 according to the first embodiment. FIG. 4(a) is a cross-sectional view of the gas spring 50 in the locked state, and FIG. 4(b) is a cross-sectional view of the gas spring 50 in the unlocked state. As shown in FIGS. 4(a) and 4(b), the gas spring 50 has a cylinder 51 whose interior is divided by a free piston 52 into a space 53 filled with compressed gas such as nitrogen gas and a space 54 filled with oil. The oil-filled space 54 is provided with a piston 56 connected to a piston rod 55. The piston 56 is provided with an orifice hole 57 and a valve 58 that switches between allowing and blocking oil flow through the orifice hole 57. The valve 58 is connected to a push rod 59 that is provided inside the piston rod 55 and is movable relative to the piston rod 55. The pressure of the compressed gas in the space 53 biases the piston 56 toward the piston rod 55. Furthermore, when no external force is applied to the push rod 59, the pressure of the compressed gas in the space 53 maintains the state in which the valve 58 is in contact with the piston 56 (the state shown in FIG. 4(a)).

[0021] When the valve 58 is in contact with the piston 56 (the state shown in FIG. 4(a)), oil cannot flow through the orifice hole 57 and the piston 56 cannot move. This causes the gas spring 50 to be in a locked state. On the other hand, when the valve 58 has moved away from the piston 56 (the state shown in FIG. 4(b)), oil can flow through the orifice hole 57 and the piston 56 can move. This causes the gas spring 50 to be in an unlocked state.

[0022] Figures 5(a) and 5(b) are views showing the vicinity of the gas spring 50 in the first embodiment. Figure 5(a) shows the gas spring 50 in a locked state, and Figure 5(b) shows the gas spring 50 in an unlocked state. As shown in Figures 5(a) and 5(b), one end of the gas spring 50 is provided with a lock operation unit 60 that switches between the locked state and the unlocked state.

[0023] The lock operating unit 60 includes a flange portion 61 attached to the end of the piston rod 55 of the gas spring 50, an arm 63 attached to the flange portion 61 so as to be swingable about a rotation shaft 62 provided on the flange portion 61, and a fixed portion 64 attached to the flange portion 61 and positioned closer to the piston rod 55 than the arm 63. An inner wire 42a of the lock wire 42 is connected to the arm 63. An end of an outer cable 42b of the lock wire 42 is attached to the fixed portion 64.

[0024] One end of the gas spring 50 is connected to the rear portion 32 of the handle rod 30 by attaching the flange portion 61 of the lock operation portion 60 to a fixing portion 36 provided on the rear portion 32 of the handle rod 30. The fixing portion 36 is provided at the center of the Y-axis direction of the rear portion 32 of the handle rod 30, protruding in the +X direction. The gas spring 50 is connected to the front portion 31 of the handle rod 30 by attaching a cylinder 51 to a fixing portion 37 fixed to a mounting member 33 provided on the front portion 31 of the handle rod 30. The fixing portion 37 is a plate-shaped member whose longitudinal direction is in the Y-axis direction, and the cylinder 51 of the gas spring 50 is fixed to its longitudinal center.

[0025] The end of the push rod 59 (not shown) is in contact with the arm 63, and when the push rod 59 is in the state shown in FIG. 4(a), it urges the arm 63 in a counterclockwise direction around the rotation shaft 62. As a result, unless the inner wire 42a is pulled, the arm 63 is maintained in the state shown in FIG. 5(a) (a state in which the arm 63 has rotated counterclockwise around the rotation shaft 62 relative to FIG. 5(b)). In this state, the valve 58 closes the orifice hole 57 provided in the piston 56, so oil cannot flow through the orifice hole 57 and the piston 56 cannot move. Therefore, in the state shown in FIG. 5(a), the gas spring 50 is in a locked state. On the other hand, when the arm 63 is pulled by the inner wire 42a of the lock wire 42 and rotates clockwise around the rotation shaft 62, as in the state shown in Figure 5(b), the push rod 59 is pushed toward the space 53 relative to the piston rod 55, as shown in Figure 4(b), and the valve 58 provided at the end of the push rod 59 moves in a direction away from the orifice hole 57. This allows oil to flow through the orifice hole 57, and the piston 56 to move. Therefore, in the state shown in Figure 5(b), the gas spring 50 is in an unlocked state.

[0026] When the gas spring 50 is in a locked state (a state in which it cannot expand or contract), the rear portion 32 of the handle rod 30 is prevented from sliding. In contrast, when the gas spring 50 is in an unlocked state (a state in which it can expand or contract), if an external force of a predetermined value or greater is applied to the rear portion 32 of the handle rod 30, the rear portion 32 of the handle rod 30 is allowed to slide in the +X direction relative to the front portion 31, and a predetermined force that resists the sliding movement is applied to the rear portion 32. In other words, the resistance force generated when the gas spring 50 compresses serves as a force that resists the sliding movement of the rear portion 32 of the handle rod 30. When the gas spring 50 compresses, oil passes through the orifice hole 57, and resistance force is generated when the gas spring 50 compresses due to the resistance when the oil passes through the orifice hole 57 and the gas pressure of the compressed gas in the space 53.

[0027] 6(a) and 6(b) show the vicinity of the shift lever 15 in the first embodiment. FIG. 6(a) shows the shift lever 15 in the N (neutral) position, and FIG. 6(b) shows the shift lever 15 in the R (reverse) position. As shown in FIGS. 6(a) and 6(b), a display panel 17 is provided near the lower end of the shift lever 15. The shift lever 15 is movable along a groove 18 provided in the display panel 17. An operator can set the shift lever 15 to a mode in which the wheels 13 do not rotate by setting the shift lever 15 to the N (neutral) position, and to a mode in which the vehicle body 10 moves backward by setting the shift lever 15 to the R (reverse) position. The R (reverse) position is located at one end of the groove 18. Setting the shift lever 15 to the L (low) position allows the vehicle body 10 to move forward at a low speed, and setting the shift lever 15 to the H (high) position allows the vehicle body 10 to move forward at a high speed. It should be noted that there may be modes other than those shown in FIGS. 6(a) and 6(b).

[0028] A moving member 19 is provided near the shift lever 15. The moving member 19 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 19 moves when a portion 19a of the moving member 19 is pressed when the shift lever 15 moves from the N (neutral) position between R (reverse) and L (low) to the R (reverse) position. An inner wire 42a of a lock wire 42 is connected to the moving member 19. An end of an outer cable 42b of the lock wire 42 is attached to a fixed part 20 that is fixed to the display panel 17 on the side of the shift lever 15 opposite the R (reverse) position.

[0029] 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 19 moves, which pulls the inner wire 42a of the lock wire 42. When the shift lever 15 returns to the N (neutral) position between R (reverse) and L (low), the moving member 19 is pulled by the inner wire 42a and returns to its original position. In the state shown in FIG. 6( a), a portion 19a of the moving member 19 abuts against a stopper 21 fixed to the display panel 17, so the moving member 19 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).

[0030] When the shift lever 15 moves from the N (neutral) position to the R (reverse) position and the moving member 19 moves, one end of the inner wire 42a of the lock wire 42 is pulled by the moving member 19. Since the other end of the inner wire 42a is connected to the arm 63 of the lock operation unit 60 (see FIGS. 5(a) and 5(b)), when one end of the inner wire 42a is pulled by the moving member 19, the arm 63 of the lock operation unit 60 is pulled.

[0031] When the inner wire 42a of the lock wire 42 pulls the arm 63 of the lock operating unit 60, the lock operating unit 60 transitions from the state shown in Fig. 5(a) to the state shown in Fig. 5(b), thereby unlocking the gas spring 50. In this way, when the operator moves the shift lever 15 to the R (reverse) position, the gas spring 50 switches from a locked state in which movement of the piston 56 is restricted to an unlocked state in which movement of the piston 56 is permitted.

[0032] Fig. 7 shows the handlebar 30 viewed from diagonally above when the shift lever 15 is in the N (neutral) position and the clutch rod 40 is not gripped. Fig. 8 shows the handlebar 30 viewed from the +Y direction when the shift lever 15 is in the N (neutral) position and the clutch rod 40 is not gripped.

[0033] 7 and 8, the clutch rod 40 is not gripped by the operator. In this case, the inner wire 41a of the clutch wire 41 connected to the clutch rod 40 is not pulled by the clutch rod 40. Since the inner wire 41a is not pulled by the clutch rod 40, the clutch is in a disengaged state. Since the shift lever 15 is in the N (neutral) position and not in the R (reverse) position, the inner wire 42a of the lock wire 42 is not pulled by the moving member 19, and the gas spring 50 is in a locked state.

[0034] Figure 9 shows the handlebar 30 viewed from diagonally above with the shift lever 15 in R (reverse) and the clutch rod 40 gripped. Figure 10 shows the handlebar 30 viewed from the +Y direction with the shift lever 15 in R (reverse) and the clutch rod 40 gripped.

[0035] 9 and 10, when the shift lever 15 is in R (reverse) and the clutch rod 40 is gripped, the inner wire 41a of the clutch wire 41 is pulled by the clutch rod 40, bringing the clutch into an engaged state, causing the walk-behind working machine 500 to move backward. With the shift lever 15 in R (reverse), the inner wire 42a of the lock wire 42 is pulled by the moving member 19, as shown in FIG. 6(b). This causes the arm 63 of the lock operating unit 60 to move to a position where it unlocks the gas spring 50.

[0036] Fig. 11 shows the handle rod 30 viewed from diagonally above 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 500 is moving backward. Fig. 12 shows the handle rod 30 viewed from the +Y direction 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 500 is moving backward.

[0037] If the walk-behind working machine 500 moves backward and the worker is pinched between an obstacle behind the worker and the handle rod 30, the rear portion 32 of the handle rod 30 will slide in the +X direction relative to the front portion 31, as shown in Figures 11 and 12. At this time, the gas spring 50 generates a substantially constant resistance to displacement, and therefore applies a predetermined amount of force to the rear portion 32 that resists the sliding movement while allowing the sliding movement of the rear portion 32 of the handle rod 30. Therefore, the rear portion 32 of the handle rod 30 will slide more slowly than if the gas spring 50 were not provided.

[0038] As the rear portion 32 of the handle rod 30 slides in the +X direction relative to the front portion 31, the distance between the clutch rod 40 and the end of the outer cable 41b of the clutch wire 41 becomes shorter, and the inner wire 41a of the clutch wire 41 returns from the state in which it was pulled by the clutch rod 40 to the state before it was pulled. As a result, the clutch is disengaged, and the transmission of power from the engine 14 to the axle 12 is interrupted. This stops the rotation of the wheels 13, and the walk-behind working machine 500 comes to a halt.

[0039] In addition, in the first embodiment, the rear portion 32 of the handlebar 30 is configured to slide to stop the supply of power to the spark plugs of the engine 14. This will be explained using FIGS. 13(a) and 13(b). FIG. 13(a) shows an enlarged view of area A in FIG. 10, and FIG. 13(b) shows an enlarged view of area A in FIG. 12. As shown in FIGS. 10 and 13(a), a switch 45 is attached to a location on the +X direction side of the mounting member 33. The switch 45 has a switching unit 46 and has the function of stopping the supply of power to the spark plugs when the switching unit 46 transitions from an unpressed state to a pressed state. In other words, the switch 45 is a kill switch that stops the supply of power to the spark plugs of the engine 14.

[0040] When the rear portion 32 of the handle rod 30 is not sliding relative to the front portion 31, the switching unit 46 is not pressed, as shown in Figures 10 and 13(a). When the rear portion 32 of the handle rod 30 slides relative to the front portion 31 in the +X direction, the guide portion 34 provided on the rear portion 32 presses the switching unit 46, as shown in Figures 12 and 13(b). In this way, the rear portion 32 of the handle rod 30 slides relative to the front portion 31, and the switching unit 46 is pressed by the guide portion 34, thereby stopping the engine 14. This also stops the rotation of the wheels 13, and the walk-behind working machine 500 stops.

[0041] The effects of the walk-behind working machine 500 according to the first embodiment will be described with reference to FIG. 14. FIG. 14 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 500 when the walk-behind working machine 500 is moving backward. The horizontal axis of FIG. 14 represents time, and the vertical axis represents the load (weight) applied to the worker. The solid line represents the change in the load (weight) for the walk-behind working machine 500 according to the first embodiment, and the dashed line represents the change in the load (weight) for a walk-behind working machine according to a comparative embodiment in which the rear portion of the handle rod does not slide relative to the front portion. A on the time axis indicates the time when pinching occurs. B to E on the time axis represent the time when the rear portion 32 of the handle rod 30 starts to slide, C when the switch 45 is activated, D when the clutch is disengaged, and E when the rear portion 32 of the handle rod 30 finishes to slide, for the walk-behind working machine 500 according to the first embodiment.

[0042] As shown in Fig. 14, in a comparative walk-behind working machine in which the handle rod does not slide, 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 500 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 32 of the handle rod 30 slides relative to the front portion 31, and the gas spring 50 applies a force to the rear portion 32 that resists the sliding movement, so that a substantially constant load (weight) corresponding to the resistance of the gas spring 50 is applied to the worker. Therefore, compared to a walk-behind working machine according to a comparative embodiment in which the handle rod does not slide, the walk-behind working machine 500 according to the first embodiment reduces the load (weight) applied to the worker when the worker is pinched during reverse travel. With the load (weight) on the worker maintained low, the switch 45 (kill switch) is activated and the clutch is disengaged by the clutch wire 41 in conjunction with the sliding movement of the rear portion 32 of the handle bar 30, thereby stopping the walk-behind working machine 500.

[0043] As described above, according to the first embodiment, the handle rod 30 has a front portion 31 (first portion) that is fixed at one end to the vehicle body 10 and extends rearward from the vehicle body 10, and a rear portion 32 (second portion) that is provided at the other end of the front portion 31 and is gripped by an operator, and the rear portion 32 is slidable in the +X direction relative to the front portion 31. The handle rod 30 is also provided with a gas spring 50 (restriction portion) that applies a force to the rear portion 32 that resists the sliding movement while allowing the sliding movement of the rear portion 32 of the handle rod 30, and a clutch wire 41 (stopping portion) and a switch 45 (stopping portion) that stop the rotation of the wheels 13 (traveling portion) by the engine 14 in conjunction with the sliding movement of the rear portion 32 of the handle rod 30. By providing gas spring 50, even if the operator is caught between an obstacle behind the operator and handle bar 30 when walking behind the work machine 500, a load corresponding to the resistance force generated when gas spring 50 is compressed is applied to the operator, thereby reducing the load (weight) applied to the operator while maintaining the operator's ability to operate the handle bar 30. Furthermore, because the rotation of wheels 13 by engine 14 stops in conjunction with the sliding movement of rear portion 32 of handle bar 30, the walk behind work machine 500 can be stopped with the load (weight) applied to the operator reduced.

[0044] Furthermore, in the first embodiment, a lock operation unit 60 is provided to prevent sliding movement of the rear portion 32 of the handlebar 30. The lock operation unit 60 releases the prevention of sliding movement of the rear portion 32 of the handlebar 30 when the vehicle body 10 is moved backward. This makes it possible to prevent the rear portion 32 of the handlebar 30 from sliding unintentionally when the vehicle body 10 is moved forward, thereby ensuring the operability of the handlebar 30.

[0045] Furthermore, in the first embodiment, the lock operating unit 60 prevents or releases the prevention of sliding movement of the rear portion 32 of the handle rod 30 by operating a valve 58 (locking mechanism) provided within the gas spring 50 to allow or prevent the expansion and contraction of the gas spring 50. This eliminates the need to provide a separate external mechanism for preventing the sliding movement of the rear portion 32 of the handle rod 30, thereby preventing the configuration of the walk-behind working machine 500 from becoming complicated.

[0046] Furthermore, in the first embodiment, the lock operating unit 60 releases the prevention of the sliding movement of the rear portion 32 of the handlebar 30 in conjunction with the operator operating the shift lever 15 (first switching unit) so that the vehicle body 10 moves backward. Since the vehicle body 10 can move backward when the shift lever 15 is operated to the R (reverse) position, by releasing the prevention of the sliding movement of the rear portion 32 of the handlebar 30 in conjunction with such an operation of the shift lever 15, it is possible to prevent the rear portion 32 of the handlebar 30 from sliding unintentionally when the vehicle body 10 moves forward.

[0047] In the first embodiment, the gas spring 50 serves as a restricting unit that applies a force to the rear portion 32 of the handle rod 30 that resists the sliding movement while allowing the rear portion 32 to slide. As a result, as shown in Fig. 14, if the operator is caught between an obstacle behind the handle rod 30 and the handle rod 30 when the walk-behind working machine 500 is moving backward, a substantially constant load (weight) corresponding to the resisting force generated when the gas spring 50 is compressed 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.

[0048] In the first embodiment, the restricting unit that applies a force resisting the sliding movement of the rear portion 32 of the handle rod 30 is the gas spring 50, 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 50. Therefore, when the operator is caught between an obstacle behind the operator and the handle rod 30, the load (weight) applied to the operator is reduced and is likely to be maintained below a certain value.

[0049] Furthermore, in the first embodiment, a switch 45 (kill switch) is provided as one of the stopping parts that stops the rotation of the wheels 13 by the engine 14 in conjunction with the sliding movement of the rear portion 32 of the handle bar 30. The switch 45 (kill switch) stops the supply of power to the spark plug of the engine 14. The operation of the switch 45 (kill switch) can be achieved solely by mechanical action, eliminating the need for an additional electrical control circuit or the like. Therefore, the rotation of the wheels 13 can be stopped in conjunction with the sliding movement of the rear portion 32 of the handle bar 30 without the need to install a new battery or other electrical components in the walk-behind working machine 500.

[0050] Furthermore, in the first embodiment, a clutch wire 41 connected to the clutch rod 40 is provided as one of the stopping parts that stops the rotation of the wheels 13 caused by the engine 14 in conjunction with the sliding movement of the rear portion 32 of the handle rod 30. The clutch wire 41 disengages the clutch between the engine 14 and the axle 12. This can be achieved solely by mechanical operation, and does not require the use of an additional electrical control circuit or the like. Therefore, the rotation of the wheels 13 can be stopped in conjunction with the sliding movement of the rear portion 32 of the handle rod 30 without the need to install a new battery or other cell in the walk-behind working machine 500.

[0051] Furthermore, in the first embodiment, even when the operator is gripping the clutch rod 40 to engage the clutch, the clutch is disengaged in conjunction with the sliding movement of the rear portion 32 of the handle rod 30. If the operator is pinched between an obstacle behind him and the rear portion 32 of the handle rod 30, the handle rod 30 will try to move upward vertically around the axle 12 while applying a horizontal force to his body as it strikes him. In such a case, the operator may not have enough time to release the clutch rod 40 because the handle rod 30 is pushing against the area near his chest and abdomen. However, even when the operator is gripping the clutch rod 40 and the clutch is engaged, the clutch is disengaged in conjunction with the sliding movement of the rear portion 32 of the handle rod 30, so that the rotation of the wheels 13 can be stopped even when there is no time to release the clutch rod 40. Furthermore, if the operator is pinched 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 40 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 sliding movement of the rear portion 32 of the handlebar 30.

[0052] Furthermore, in the first embodiment, in conjunction with the sliding movement of the rear portion 32 of the handlebar 30, both the supply of power to the spark plug of the engine 14 and the clutch between the engine 14 and the axle 12 are stopped. This makes it possible to more reliably stop the rotation of the wheels 13 if the operator is pinched between an obstacle behind the operator and the handlebar 30.

[0053] In the first embodiment, in conjunction with the sliding movement of the rear portion 32 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.

[0054] Second Embodiment In the first embodiment described above, the lock operating unit 60 releases the prevention of sliding movement of the rear portion 32 of the handlebar 30 in conjunction with the operator operating the shift lever 15 to move the vehicle body 10 backward. In the second embodiment, a case will be described in which the lock operating unit 60 releases the prevention of sliding movement of the rear portion 32 of the handlebar 30 in conjunction with the operator operating the shift lever 15 to move the vehicle body 10 backward and operating the clutch rod 40 to achieve a transmission state in which power is transmitted from the engine 14 to the axle 12.

[0055] Figure 15 shows a walk-behind working machine 600 according to the second embodiment as viewed from the +Z direction. As shown in Figure 15, the second embodiment is provided with a lock switching mechanism 70 that switches the inner wire 42a of the lock wire 42 between a state in which it is not pulled or is slightly pulled, and a state in which the inner wire 42a is pulled greatly, in response to the operator's operation of the shift lever 15 and the clutch rod 40. The lock switching mechanism 70 is attached, for example, to the front portion 31 of the handlebar rod 30 near the vehicle body 10.

[0056] In addition to the inner wire 41a of the clutch wire 41, an inner wire 43a of the connecting wire 43 is also connected to the clutch rod 40. Like the inner wire 41a, the inner wire 43a is connected to the clutch rod 40 on the opposite side of the rear portion 32 of the handle rod 30 from the rotation axis of the clutch rod 40, which is provided below the rear portion 32 of the handle rod 30. Like the outer cable 41b of the clutch wire 41, the end of the outer cable 43b of the connecting wire 43 is attached at a position such that the distance from the end of the outer cable 43b to the attachment position of the inner wire 43a to the clutch rod 40 becomes small when the operator releases the clutch rod 40 or when the rear portion 32 of the handle rod 30 slides relative to the front portion 31. For example, the end of the outer cable 43b is attached to a fixing portion 35 that is fixed to an attachment member 33 provided on the front portion 31 of the handle rod 30. The connecting wire 43 is connected to the lock switching mechanism 70 on the opposite side to the side connected to the clutch rod 40 .

[0057] The inner wire 42a of the lock wire 42 is connected to the arm 63 of the lock operation unit 60, as in the first embodiment, and the end of the outer cable 42b is attached to the fixed portion 64 of the lock operation unit 60, as in the first embodiment (see FIGS. 5(a) and 5(b)). The side of the lock wire 42 opposite to the side connected to the lock operation unit 60 is connected to the lock switching mechanism 70. In addition, a connecting wire 44 is connected between the indicator plate 17 provided near the lower end of the shift lever 15 and the lock switching mechanism 70.

[0058] Figures 16(a) and 16(b) show the vicinity of the shift lever 15 in the second embodiment. Figure 16(a) shows the shift lever 15 in the N (neutral) position, and Figure 16(b) shows the shift lever 15 in the R (reverse) position. As shown in Figures 16(a) and 16(b), in this second embodiment, an inner wire 44a of a connecting wire 44 is connected to a moving member 19 provided near the shift lever 15. An end of an outer cable 44b of the connecting wire 44 is attached to a fixing portion 20 fixed to the display panel 17. When the shift lever 15 is moved to the R (reverse) position, the moving member 19 moves, and the inner wire 44a of the connecting wire 44 is pulled.

[0059] Figures 17(a) and 17(b) show the lock switching mechanism 70 when the shift lever 15 is set to a position other than R (reverse). Figures 18(a) and 18(b) show the lock switching mechanism 70 when the shift lever 15 is set to R (reverse). An end of the outer cable 42b of the lock wire 42, an end of the outer cable 43b of the connecting wire 43, and an end of the outer cable 44b of the connecting wire 44 are attached to the lock switching mechanism 70.

[0060] The end of the outer cable 42b of the lock wire 42 opposite the lock switching mechanism 70 is attached to the fixed part 64 of the lock operating part 60, as shown in Figures 5(a) and 5(b). The end of the outer cable 43b of the connection wire 43 opposite the lock switching mechanism 70 is attached to the fixed part 35 provided on the front part 31 of the handlebar rod 30, as shown in Figure 15. The end of the outer cable 44b of the connection wire 44 opposite the lock switching mechanism 70 is attached to the fixed part 20 fixed to the display panel 17, as shown in Figures 16(a) and 16(b).

[0061] The lock switching mechanism 70 changes the degree to which the inner wire 42a of the lock wire 42 is pulled depending on the states of the connecting wires 43 and 44. As shown in Figure 18(b), when the lock switching mechanism 70 pulls the inner wire 42a of the lock wire 42 to a greater extent, the arm 63 of the lock operating unit 60 is pulled by the inner wire 42a, and the gas spring 50 is unlocked. The lock switching mechanism 70 will be described in detail below.

[0062] FIG. 17(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 40 is not gripped by the operator. FIG. 17(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 40 is gripped by the operator. FIG. 18(a) shows a state in which the shift lever 15 is in the R (reverse) position and the clutch rod 40 is not gripped by the operator. FIG. 18(b) shows a state in which the shift lever 15 is in the R (reverse) position and the clutch rod 40 is gripped by the operator.

[0063] As shown in FIG. 17(a), the lock switching mechanism 70 includes a plate-shaped member 71, rotating members 72 and 73 provided on the plate-shaped member 71, and torsion coil springs 74 and 75. Ends of outer cables 43b and 44b of the connection wires 43 and 44 are attached to the plate-shaped member 71. The plate-shaped member 71 has a generally rectangular shape when viewed from above, and includes four sides 71a, 71b, 71c, and 71d. Side 71a faces side 71b, and side 71c faces side 71d. The outer cable 43b of the connection wire 43 extends onto the plate-shaped member 71 from the side of side 71d, and its end is attached to the plate-shaped member 71 near the corner between sides 71b and 71d. The outer cable 44b of the connecting wire 44 extends onto the plate-shaped member 71 from the side 71c, and its end is attached to the plate-shaped member 71 near the corner between the sides 71a and 71c. The rotating member 72 is provided between the rotating member 73 and the side 71c of the plate-shaped member 71, and the rotating member 73 is provided between the rotating member 72 and the side 71d of the plate-shaped member 71. The rotating member 72 is rotatable about a shaft 76 provided on the plate-shaped member 71. The rotating member 73 is rotatable about a shaft 77 provided on the plate-shaped member 71. The shaft 76 is located near the side 71b, and the shaft 77 is located near the side 71a.

[0064] A pillar-shaped portion 78 that functions as a stopper is provided between the rotating members 72 and 73. The outer cable 42b of the lock wire 42 extends onto the plate-shaped member 71 from the side 71c of the plate-shaped member 71, and its end is fixed to the rotating member 72 near the center, in the direction along side 71c, between the shaft 76 and the location where the end of the outer cable 44b of the connection wire 44 is attached to the plate-shaped member 71. The end of the inner wire 42a of the lock wire 42 is hooked onto a notch provided in the rotating member 73 near the center, in the direction along side 71d, between the shaft 77 and the location where the end of the outer cable 43b of the connection wire 43 is attached to the plate-shaped member 71. With this configuration, when the state shown in FIG. 18(b) is achieved, the inner wire 43a of the connection wire 43 and the inner wire 44a of the connection wire 44 each pull approximately half of the inner wire 42a of the lock wire 42.

[0065] The end of the inner wire 44a of the connecting wire 44 connected to the moving member 19 (see Figures 16(a) and 16(b)) opposite to the moving member 19 is hooked to a location on the opposite side of the pivoting member 72 from the shaft 76. As shown in Figure 16(b), when the operator moves the shift lever 15 to the R (reverse) position, the moving member 19 moves, and one end of the inner wire 44a is pulled by the moving member 19, causing the other end of the inner wire 44a to pull the pivoting member 72. As a result, as shown in Figures 18(a) and 18(b), the pivoting member 72 pivots clockwise around the shaft 76. On the other hand, when the operator returns the shift lever 15 from the state shown in Figure 16(b) to the N (neutral) position, the rotating member 72 returns to its original position as shown in Figures 17(a) and 17(b) due to the biasing force of the torsion coil spring 74, which rotates the rotating member 72 about the shaft 76 and applies a force to the rotating member 72 pressing it against the columnar portion 78. As a result, the rotating member 72 pulls the inner wire 44a, and the moving member 19 returns to its original position shown in Figure 16(a).

[0066] The end of the inner wire 43a of the connecting wire 43 connected to the clutch rod 40 (see FIG. 15) opposite the clutch rod 40 is hooked into a notch provided on the side of the rotating member 73 opposite the shaft 77. When the operator grips the clutch rod 40 together with the rear portion 32 of the handle rod 30, one end of the inner wire 43a is pulled by the clutch rod 40. As a result, the other end of the inner wire 43a pulls the rotating member 73, and as shown in FIGS. 17(b) and 18(b), the rotating member 73 rotates clockwise about the shaft 77. On the other hand, when the operator releases the clutch rod 40, the rotating member 73 returns to its original position as shown in FIGS. 17(a) and 18(a) due to the biasing force of the torsion coil spring 75, which rotates the rotating member 73 about the shaft 77 and applies a force to the rotating member 73 pressing it against the columnar portion 78.

[0067] As shown in Figure 17(b), when the rotating member 72 does not rotate and only the rotating member 73 rotates clockwise, the inner wire 42a of the lock wire 42 is slightly pulled. Similarly, as shown in Figure 18(a), when the rotating member 72 rotates clockwise and the rotating member 73 does not rotate, the inner wire 42a of the lock wire 42 is slightly pulled. On the other hand, as shown in Figure 18(b), when the rotating members 72 and 73 rotate clockwise, the inner wire 42a of the lock wire 42 is pulled more strongly than in the cases of Figures 17(b) and 18(a). Because the inner wire 42a is connected to the arm 63 of the lock operation unit 60 (see Figures 5(a) and 5(b)), the inner wire 42a is pulled more strongly, which in turn pulls the arm 63 of the lock operation unit 60. As a result, the lock operating unit 60 transitions from the state shown in Figure 5(a) to the state shown in Figure 5(b), and the gas spring 50 is unlocked. In this way, when the operator moves the shift lever 15 to the R (reverse) position and grips the clutch rod 40, the gas spring 50 switches from a locked state in which movement of the piston 56 is restricted to an unlocked state in which movement of the piston 56 is permitted. Note that when the inner wire 42a is slightly pulled as shown in Figures 17(b) and 18(a), the gas spring 50 is not unlocked.

[0068] As the rear portion 32 of the handlebar 30 slides relative to the front portion 31, the inner wire 41a of the clutch wire 41 returns from a state in which it was pulled by the clutch rod 40 to a state before it was pulled. Furthermore, the inner wire 43a of the connection wire 43 also returns from a state in which it was pulled by the clutch rod 40 to a state before it was pulled. Therefore, the lock switching mechanism 70 transitions from the state shown in FIG. 18(b) to the state shown in FIG. 19. FIG. 19 shows the lock switching mechanism 70 after the rear portion 32 of the handlebar 30 has slid. As a result of the transition to the state shown in FIG. 19, the arm 63 of the lock operating unit 60 transitions from the state shown in FIG. 5(b) to the state shown in FIG. 5(a), moving to a position where the gas spring 50 is locked. At this time, it is preferable that the inner wire 41a of the clutch wire 41 is no longer pulled, disengaging the clutch and shutting off power, and the wheel 13 stops, after which the gas spring 50 is locked. In this way, after the inner wire 41a is no longer pulled and the wheel 13 stops, the gas spring 50 enters a locked state, and the rear portion 32 of the handle rod 30 becomes fixed, allowing the worker to push the rear portion 32 of the handle rod 30 to move the walk-behind working machine 600 or to use the rear portion 32 of the handle rod 30 as a means to escape from a pinched state.

[0069] As described above, according to the second embodiment, lock operating unit 60 releases the prevention of sliding movement of rear portion 32 of handlebar rod 30 in conjunction with the operator operating shift lever 15 (first switching unit) to move vehicle body 10 backward and operating clutch rod 40 (second switching unit) to establish a transmission state in which power is transmitted from engine 14 to axle 12. Since vehicle body 10 starts moving backward when shift lever 15 is operated to the R (reverse) position and clutch rod 40 is gripped, by releasing the prevention of sliding movement of rear portion 32 of handlebar rod 30 in conjunction with the operation of shift lever 15 and clutch rod 40, rear portion 32 of handlebar rod 30 can be made to slide when vehicle body 10 moves backward.

[0070] In the second embodiment, when the worker is caught between a rear obstacle and the handlebar 30 and the rear portion 32 of the handlebar 30 slides relative to the front portion 31, causing the wheels 13 to stop, the gas spring 50 may remain in the unlocked state without transitioning to the locked state. In this case, the rear portion 32 of the handlebar 30 moves, allowing the worker caught between the obstacle and the handlebar 30 to move the rear portion 32 of the handlebar 30 and escape.

[0071] In the second embodiment, the structure of the lock switching mechanism 70 shown in Figures 17(a) to 19 is one example, and other structures may be used as long as the functions described in the claims can be realized.

[0072] Third Embodiment FIG. 20 shows a walk-behind working machine 700 according to the third embodiment, viewed obliquely from above. As shown in FIG. 20, the walk-behind working machine 700 has a handle rod 30a attached to the vehicle body 10. The handle rod 30a has one end fixed to the vehicle body 10 and a front portion 31a extending rearward from the vehicle body 10, and a rear portion 32a attached to the other end of the front portion 31a and gripped by the operator. The rear portion 32a is slidable and rotatable relative to the front portion 31a. While the front portion 31a has the same structure as the front portion 31 in the first embodiment, the rear portion 32a has a U-shaped, dual-handle structure with left and right grips for the operator to grip. A clutch rod 40 is attached to one of the left and right grips. The rest of the configuration is the same as that of the walk-behind working machine 500 according to the first embodiment, and therefore a description thereof will be omitted.

[0073] In the first embodiment described above, the rear portion 32 of the handlebar 30 has an annular shape, but as in the third embodiment, the rear portion 32a of the handlebar 30a may have a U-shape.

[0074] Fourth Embodiment In the first to third embodiments described above, the gas spring 50 is provided with a locking mechanism as shown in Figures 4(a) and 4(b), but in this fourth embodiment, a case will be described in which a gas spring 50a without a locking mechanism is used. Since the components other than the gas spring 50a and the lock operating part 60a are the same as those in the first embodiment described above, the gas spring 50a and the lock operating part 60a will be mainly described.

[0075] 4(a) and 4(b), the gas spring 50a differs in that it does not have the valve 58 or the push rod 59. Therefore, oil can always flow through the orifice hole 57.

[0076] FIG. 21(a) shows the vicinity of the lock operation portion 60a when the gearshift lever 15 is in a position other than R (reverse) in the fourth embodiment, and FIG. 21(b) shows an enlarged view of region A in FIG. 21(a). As shown in FIGS. 21(a) and 21(b), the lock operation portion 60a includes reverse movement preventing members 80, 81, a plate-shaped gear 82, a leaf spring 83, and a torsion spring 84. The reverse movement preventing member 80 has a main body 80a and a claw portion 80b provided at an end of the main body 80a. Similarly, the reverse movement preventing member 81 has a main body 81a and a claw portion 81b provided at an end of the main body 81a. The main body 80a of the reverse movement preventing member 80 and the main body 81a of the reverse movement preventing member 81 are rotatably connected to each other by a joint 86 at the ends opposite the claw portions 80b, 81b. Furthermore, the main body 80a of the reverse movement preventing member 80 and the main body 81a of the reverse movement preventing member 81 are rotatably connected to the fixed part 38 by a joint 85. The fixed part 38 is fixed to the mounting member 33.

[0077] Reverse movement preventing member 80 is located in the -X direction relative to reverse movement preventing member 81, and reverse movement preventing member 81 is located in the +X direction relative to reverse movement preventing member 80. Claw portions 80b, 81b have a surface on the joint 85 side that is inclined in a forward tapered manner, and a surface on the opposite side to joint 85 that is nearly vertical or slightly inclined in a reverse tapered manner.

[0078] The leaf spring 83 is provided across the main body 80a of the reverse movement preventing member 80 and the main body 81a of the reverse movement preventing member 81. The leaf spring 83 is fixed to an end of the main body 80a of the reverse movement preventing member 80 on the surface opposite to the claw portion 80b, on the claw portion 80b side.

[0079] The torsion spring 84 is wound around the joint 85, and one end of the torsion spring 84 abuts against a protrusion 87 provided on the main body 80a of the reverse movement preventing member 80, biasing the main body 80a toward the claw 80b. The other end of the torsion spring 84 is fixed to the fixed part 38.

[0080] A pair of fixing portions 88 that sandwich the main body portion 80a of the reverse movement preventing member 80 are provided on the side surface on the claw portion 80b side of the main body portion 80a. A joint 89 that extends from one of the pair of fixing portions 88 to the other and is rotatable relative to the fixing portions 88 is provided. An inner wire 42a of the lock wire 42 is connected to the joint 89. An outer cable 42b of the lock wire 42 is attached to the fixing portion 38 above the joint 89.

[0081] Plate-shaped gear 82 is provided on guide portion 34 facing reverse movement-preventing members 80, 81. When shift lever 15 is in a position other than R (reverse), inner wire 42a of lock wire 42 is not pulled by moving member 19 (see FIG. 6(a)), and therefore, main body 80a of reverse movement-preventing member 80 is urged toward claw portion 80b by the urging force of torsion spring 84, and claw portion 80b is fitted into gear 82. In this state, rear portion 32 of handlebar 30 can slide in the -X direction relative to front portion 31, but cannot slide in the +X direction. Therefore, gas spring 50a is in a locked state where it cannot compress.

[0082] FIG. 22(a) shows the vicinity of the lock operation portion 60a when the shift lever 15 is in R (reverse) in the fourth embodiment, and FIG. 22(b) shows an enlarged view of region A in FIG. 22(a). As shown in FIGS. 22(a) and 22(b), when the shift lever 15 is in R (reverse), the inner wire 42a of the lock wire 42 is pulled by the moving member 19 (see FIG. 6(b)). As a result, the reverse movement preventing member 80 is pulled by the inner wire 42a. As the reverse movement preventing member 80 is pulled by the inner wire 42a, the reverse movement preventing member 80 and the reverse movement preventing member 81 rotate counterclockwise about the joint 85, and the claw portion 81b of the reverse movement preventing member 81 fits into the gear 82. As a result, the rear portion 32 of the handlebar 30 can slide in the +X direction relative to the front portion 31, but cannot slide in the −X direction. Thus, the gas spring 50a is in an unlocked state in which it can be compressed.

[0083] Fig. 23(a) shows the vicinity of lock operating portion 60a when an operator is caught between an obstacle behind and handle rod 30 and rear portion 32 of handle rod 30 slides relative to front portion 31 in the fourth embodiment, and Fig. 23(b) shows an enlarged view of area A in Fig. 23(a). As shown in Figs. 23(a) and 23(b), rear portion 32 of handle rod 30 is slidable in the +X direction relative to front portion 31. Therefore, when an operator is caught between an obstacle behind and handle rod 30, rear portion 32 of handle rod 30 slides in the +X direction relative to front portion 31. During this sliding movement, gas spring 50a applies a predetermined force to rear portion 32 of handle rod 30 that resists the sliding movement while allowing the sliding movement of rear portion 32 of handle rod 30. Therefore, if the worker is pinched between an obstacle behind him and the handlebar 30, the worker will be subjected to a load corresponding to the resistance force when the gas spring 50a contracts, thereby reducing the load (weight) on the worker while maintaining the worker's ability to operate the handlebar 30.

[0084] Furthermore, reverse movement preventing member 81 is urged toward gear 82 by the urging force of leaf spring 83, causing pawl 81b to fit into a recess in gear 82. For pawl 81b to move to a recess next to gear 82, reverse movement preventing member 81 must press leaf spring 83 with a force greater than the force with which leaf spring 83 urges reverse movement preventing member 81. In other words, when a force greater than the force with which leaf spring 83 urges reverse movement preventing member 81 is applied to rear portion 32 of handle rod 30, pawl 81b moves between the recesses in gear 82, causing rear portion 32 of handle rod 30 to slide. In this way, the force required for rear portion 32 of handle rod 30 to start sliding can be adjusted by the urging force of leaf spring 83.

[0085] For example, if the gas spring 50a begins to compress when a load greater than the initial reaction force of the gas spring 50a is applied to the rear portion 32 of the handle rod 30, the initial reaction force of the gas spring 50a is set to a magnitude that minimizes injury to an operator who is trapped between the handle rod 30 and an obstacle behind the operator and does not impair operability of the handle rod 30 during reverse travel. However, in this case, the initial reaction force of the gas spring 50a becomes somewhat large. Because the reaction force of the gas spring 50a during compression is greater than the initial reaction force, there is a risk of increasing the load on an operator who is trapped between the obstacle behind the operator and the handle rod 30. In response to this, the force required to initiate sliding movement of the rear portion 32 of the handle rod 30 can be adjusted by the biasing force of the leaf spring 83, allowing the initial reaction force of the gas spring 50a to be freely set. Therefore, by setting the initial reaction force of the gas spring 50a low and preventing the reaction force of the gas spring 50a from becoming too high during compression, the load on the operator can be reduced. Furthermore, by adjusting the biasing force of the leaf spring 83, even if the initial reaction force of the gas spring 50a is set low, it is possible to prevent the operability of the handlebar 30 from becoming worse.

[0086] For example, the lock operating unit 60a may be configured to release the prevention of sliding movement of the rear portion 32 of the handle rod 30 when a force 1.5 times or more the initial reaction force of the gas spring 50a is applied to the rear portion 32, or when a force twice or more is applied, or when a force 2.5 times or more is applied.

[0087] As described above, according to the fourth embodiment, the lock operating unit 60a blocks or releases the blocking of the sliding movement of the rear portion 32 of the handle rod 30 by moving the reverse movement blocking members 80, 81 (blocking members) provided on the outside of the gas spring 50a to block the sliding movement of the rear portion 32 of the handle rod 30. This allows the use of a gas spring 50a that does not have a locking mechanism.

[0088] Furthermore, in the fourth embodiment, the lock operating unit 60a releases the prevention of sliding movement of the rear portion 32 when a load greater than the initial reaction force of the gas spring 50a is applied to the rear portion 32 of the handlebar 30 while the vehicle body 10 is moving backward. This allows the initial reaction force of the gas spring 50a to be freely set, and for example, can be set low to prevent the reaction force from becoming too high during contraction, thereby preventing the load applied when the operator is pinched between an obstacle and the handlebar 30 from becoming too large.

[0089] Fifth Embodiment In this fifth embodiment, as in the fourth embodiment, a gas spring 50a without a locking mechanism is used. Figures 24(a) to 24(c) show the vicinity of the lock operation portion 60b in the fifth embodiment. Figure 24(a) shows the vicinity of the lock operation portion 60b when the gearshift lever 15 is in a position other than R (reverse). Figure 24(b) shows the vicinity of the lock operation portion 60b when the gearshift lever 15 is in R (reverse). Figure 24(c) shows the vicinity of the lock operation portion 60b when the operator is pinched between an obstacle behind the operator and the handlebar 30.

[0090] As shown in FIG. 24(a), the lock operating unit 60b includes a link mechanism 90 and a blocking unit 101. The link mechanism 90 is attached to the mounting member 33. The blocking unit 101 is provided next to the guide unit 34 between the mounting member 33 and the rear portion 32 of the handlebar 30. The link mechanism 90 includes links 91, 92, and 93. One end of the link 91 is rotatably connected to a protrusion 33a provided on the mounting member 33 by a joint 94, and the other end is rotatably connected to one end of the link 92 by a joint 95. An inner wire 42a of the lock wire 42 is connected to the center of the link 91 by a joint 96. An outer cable 42b of the lock wire 42 is attached to the mounting member 33 below the link 91.

[0091] The central portion of link 92 is rotatably connected by joint 97 to protrusion 33b provided on mounting member 33, and the other end is rotatably connected by joint 98 to protrusion 101a provided on blocking portion 101. Link 93 is provided parallel to the portion from the central portion to the other end of link 92, and one end is rotatably connected by joint 99 to protrusion 33b of mounting member 33, and the other end is rotatably connected to protrusion 101a of blocking portion 101 by joint 100.

[0092] As shown in Figure 24(a), when the gearshift lever 15 is in a position other than R (reverse), the inner wire 42a of the lock wire 42 is not pulled by the moving member 19 (see Figure 6(a)), and therefore the link 91 is not pulled by the inner wire 42a. In this case, the blocking portion 101 is located between the mounting member 33 and the rear portion 32 of the handlebar 30, and the rear portion 32 of the handlebar 30 cannot slide in the +X direction relative to the front portion 31. Therefore, the gas spring (not shown) is in a locked state where it cannot contract.

[0093] As shown in FIG. 24(b), when the gearshift lever 15 is in R (reverse), the inner wire 42a of the lock wire 42 is pulled by the moving member 19 (see FIG. 6(b)), which causes the central portion of the link 91 to be pulled by the inner wire 42a. As the central portion of the link 91 is pulled by the inner wire 42a, the link 92 rotates counterclockwise around the joint 97. As a result, the blocking portion 101 is lifted by the link 92 and moves upward from between the mounting member 33 and the rear portion 32 of the handlebar 30. This allows the rear portion 32 of the handlebar 30 to slide in the +X direction relative to the front portion 31. This causes the gas spring (not shown) to enter an unlocked state in which it can be compressed.

[0094] As shown in FIG. 24(c), when an operator is caught between an obstacle behind and the handle rod 30, the rear portion 32 of the handle rod 30 is slidable in the +X direction relative to the front portion 31, and therefore the rear portion 32 of the handle rod 30 slides relative to the front portion 31. During this sliding movement, a gas spring (not shown) applies a predetermined force to the rear portion 32 that resists the sliding movement while allowing the rear portion 32 of the handle rod 30 to slide. Therefore, when an operator is caught between an obstacle behind and the handle rod 30, a load corresponding to the resistance force generated when the gas spring contracts is applied to the operator, and the load (weight) applied to the operator can be reduced while maintaining the operator's ability to operate the handle rod 30.

[0095] As described above, according to the fifth embodiment, the lock operating unit 60b blocks or releases the blocking of the rear portion 32 of the handle rod 30 by moving the blocking unit 101 (blocking member) provided on the outside of the gas spring 50a to block the sliding movement of the rear portion 32 of the handle rod 30. This allows the use of a gas spring 50a that does not have a locking mechanism.

[0096] 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]

[0097] 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 18 Groove 19 Moving parts 19a Part of the moving member 20 Fixed part 21 Stopper 30, 30a handlebar 31, 31a Front part of handlebar (first part) 32, 32a Rear part of handlebar (second part) 33 Mounting material 33a, 33b protrusion 34 Guide section 35, 36, 37, 38 Fixed part 40 Clutch rod 41 Clutch wire 41a Clutch cable inner wire 41b Clutch wire outer cable 42 Lock wire 42a Lockwire inner wire 42b Lockwire outer cable 43 connecting wires 43a Inner wire of connecting wire 43b Outer cable of connecting wire 44 connecting wires 44a Inner wire of connecting wire 44b Outer cable of connecting wire 45 Switch 46 Switching section 50, 50a gas spring 51 cylinders 52 Free Piston 53, 54 space 55 Piston rod 56 Piston 57 Orifice 58 Valve 59 Push rod 60, 60a, 60b Lock operation part 61 Flange 62 Rotation axis 63 Arm 64 Fixed part 70 Lock switching mechanism 71 Plate-shaped members 71a, 71b, 71c, 71d Sides of plate-like member 72, 73 Rotating members 74, 75 Torsion coil springs Axis 76, 77 78 Columnar part 80, 81 Reverse movement prevention member 80a, 81a Main body 80b, 81b claw part 82 Gears 83 Leaf spring 84 Torsion spring 85, 86 joints 87 Protrusion 88 Fixed part 89 Joint 90 Link mechanism 91, 92, 93 Links 94, 95, 96, 97, 98, 99, 100 Joints 101 Blocking part 101a Protrusion 500, 600, 700 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 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 being slidable in a forward direction of the vehicle body relative to the first portion; a restricting portion that applies a force to the second portion against the sliding movement while allowing the sliding movement of the second portion; a stopper that stops the traveling of the traveling unit in conjunction with the sliding movement of the second portion; a lock operation portion for preventing the sliding movement of the second portion, The lock operation unit releases the prevention of the sliding movement of the second portion when the vehicle body is moved backward.

2. The walk-behind working machine according to claim 1, wherein the lock operating unit operates a locking mechanism provided within the regulating unit to allow or prevent extension and contraction of the regulating unit, thereby preventing or releasing the prevention of the sliding movement of the second part.

3. 2. The walk-behind working machine according to claim 1, wherein the lock operating unit prevents the sliding movement of the second part or releases the prevention of the sliding movement by moving a blocking member provided outside the regulating unit to prevent the sliding movement of the second part.

4. a first switching unit that is operated by the operator to switch the traveling direction of the vehicle body between forward and reverse; 4. The walk-behind working machine according to claim 1, wherein the lock operating unit releases the prevention of the sliding movement of the second part in conjunction with the operator operating the first switching unit so as to move the vehicle body backward.

5. 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 disconnection state in which the power is disconnected, 4. The walk-behind working machine according to claim 1, wherein the lock operating unit releases the prevention of the sliding movement 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.

6. 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 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 being slidable in a forward direction of the vehicle body relative to the first portion; a restricting portion that applies a force to the second portion against the sliding movement while allowing the sliding movement of the second portion; a stopper that stops the traveling of the traveling unit in conjunction with the sliding movement of the second portion; a lock operation portion for preventing the sliding movement of the second portion, The lock operating unit releases the prevention of the sliding movement 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.

7. 7. The walk-behind working machine according to claim 1, wherein the restricting portion is a gas spring or a shock absorber.

8. the drive unit is a motor, 7. The walk-behind working machine according to claim 1, wherein the stopping portion stops supplying power to an ignition plug of the engine in response to the sliding movement of the second portion.

9. 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 traveling unit in conjunction with the sliding movement of the second portion.

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

11. the drive unit is a motor, 7. The walk-behind working machine according to claim 1, wherein the stopping unit 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 in response to the sliding movement of the second part.

Images