JP2008289402A - Lawn mower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lawn mower making elimination of the need for replacing a grass collection box with a throwing cover compatible with prevention of unprepared driving of a lawn mowing mechanism though simply discharging cut grass in the grass collection box to a container etc. <P>SOLUTION: A bottom lid plate 20 for openably and closably closing an opening at the base of the grass collection box 18 is composed so as to enable opening operation in such a state that the grass collection box 18 is held in the lowered position for receiving the cut grass. When the grass collection box 18 is held in the lowered position and the bottom lid plate 20 is maintained in a prescribed opening and closing posture, a PTO clutch is composed so as to be a power connection state only when a PTO operation lever 52 is subjected to IN operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lawn mower provided with a lawn mowing mechanism for mowing turf grass planted on the ground and a grass collecting box for collecting the grass cut by the lawn mowing mechanism. It is related with the lawn mower comprised so that the mowing grass in a grass collection box may be discharged | emitted after raising to a height position.

  Conventionally, this type of lawn mower is configured to continuously cut turf grass planted on the ground by a lawn mowing mechanism and collect it in a grass collection box through a discharge duct extending rearward from the lawn mowing mechanism. . Patent Documents 1 and 2 disclose an example of a lawn mower.

The lawn mowers of Patent Documents 1 and 2 are of a so-called high dump specification, and include a lift mechanism for lifting the grass collection box to a predetermined height position. The rear opening of the grass collection box is closed by a rear cover plate that can be opened and closed. In this case, after lifting the grass collection box in which the grass is collected to a predetermined height by driving the lift mechanism, the rear opening is opened downward (facing the ground) while opening the rear cover plate, When the grass collection box rotates and changes its posture, the cut grass in the grass collection box is discharged to a container, a truck bed, or the like.
JP 2001-275438 A JP 2002-84950 A

  By the way, as a form of the mowing work, there is not only a form in which the mowing grass cut by the lawn mowing mechanism is collected in the grass collection box, but also a form in which the mowing is spread so as to be spread on the ground without collecting the mowing grass.

  When carrying out the release work, after removing the grass collection box from the rear part of the traveling machine body, a release cover for changing the discharge direction of the cut grass is attached to the rear part. Then, while traveling on the field with a lawn mower with a release cover, the lawn grass planted on the ground is continuously mowed by the lawn mowing mechanism, and the mowed grass released backward from the discharge duct is released once by the cover. It is received and sprayed on the ground (downward).

  However, in the conventional configuration, in order to use the grass collection box and the release cover properly according to the work form, it is necessary to perform troublesome and troublesome replacement work each time, and the work efficiency is poor. there were. In addition, if the lawn mowing mechanism is inadvertently driven with the grass collection box raised to a predetermined height during the mowing discharge operation, the mowing grass will be removed from the rear end discharge port of the discharge duct exposed to the outside. As a result, pebbles, etc. were scattered behind the traveling aircraft, and there was a risk of injury if a person was behind the traveling aircraft.

  Therefore, the invention of the present application makes it possible to easily discharge the mowing grass in the grass collecting box to a container, a truck bed, etc., while eliminating the need to replace the grass collecting box and the release cover, and the lawn mowing mechanism. It is a technical problem to provide a lawn mower that is compatible with preventing inadvertent driving.

  In order to achieve this technical problem, the invention of claim 1 is directed to a lawn mowing mechanism mounted on a traveling machine body, a grass collection box communicating with a discharge duct extending from the lawn mowing mechanism, and lifting the grass collection box. A lawn mower comprising a lift mechanism for opening and a PTO operation body for turning on and off the lawn mowing mechanism, wherein the grass collecting box covers the opening formed on the bottom surface so as to be openable and closable. And the bottom cover plate is configured to be openable in a state where the grass collection box is held at a lowered position for receiving cut grass, and is used for detecting the vertical position of the grass collection box. Detection means, attitude detection means for detecting the opening / closing attitude of the bottom cover plate, PTO detection means for detecting the on / off operation state of the PTO operating body, and an engine mounted on the traveling machine body from the turf Clutch means for interrupting transmission of power to the feed mechanism, the grass collection box detecting the grass collection box in the lowered position, and the bottom cover plate is opened and closed at a predetermined level It is said that the clutch means is configured to be in a power connection state only when the PTO detection means detects an entry operation of the PTO operating body when the posture detection means detects that the posture is detected. Is.

  According to a second aspect of the present invention, in the lawn mower according to the first aspect, the bottom cover plate projects from the cut grass receiving port of the grass collection box toward the discharge duct in a state where the bottom cover plate is closed. A bottom guide plate is attached, and the bottom cover plate is configured to rotate so that at least the bottom guide plate side jumps up into the grass collection box, and the grass collection box is in the lowered position. The bottom cover plate that has been opened and rotated in a state is configured to be held in an outgoing inclined posture with the tip portion of the bottom guide plate facing the upper part of the cut grass discharge port in the discharge duct, The opening / closing postures of the bottom cover plate detected by the posture detecting means are a closing posture and a tilting posture.

  According to the present invention, when the grass collection box is in the lowered position and the bottom cover plate that covers the bottom opening of the grass collection box so as to be openable / closable is in a predetermined opening / closing posture, Only when the PTO operation body is entered and operated, the clutch means for interrupting power transmission from the engine to the lawn mowing mechanism is configured to be in a power connection state, so that the grass collection box is in the raised position. Even if the operator erroneously enters and operates the PTO operation body (at the time of the grass cutting release operation), the clutch means is maintained in a power cut-off state, and the lawn mowing mechanism is not driven. For this reason, it is possible to prevent the grass and pebbles from being inadvertently scattered from the discharge duct exposed outside to the rear of the traveling machine body.

  Further, for example, even when the grass collection mechanism is driven, the grass collection box is moved to the lowered position even if the grass collection box is erroneously touched by an operation means for raising / lowering the grass collection box or opening / closing the bottom cover plate. Since the clutch means is powered off and the driving of the lawn mowing mechanism automatically stops when the bottom cover plate is removed from the predetermined opening / closing posture, the discharge duct is also stopped in this case. Therefore, it is possible to prevent the grass and pebbles from being inadvertently scattered behind the traveling machine body.

  When the grass collecting box is in the lowered position and the bottom cover plate is in a predetermined opening / closing posture, the lawn mower mechanism is allowed to be driven. Needless to say, the work can be done without any problems.

  In particular, according to the invention of claim 2, the opening / closing posture of the bottom cover plate detected by the posture detecting means is a closed posture in which the bottom opening of the grass collection box is closed, and the front end portion of the bottom guide plate is discharged. When the bottom cover plate is in a halfway open position that is neither in the closed position nor in the inclined position, the lawn mowing mechanism is set so as to face the upper part of the cut grass outlet in the duct. Driving is prohibited. For this reason, for example, the operator can easily grasp whether or not the bottom cover plate is in an appropriate discharge inclination posture from the presence / absence of the driving of the lawn mowing mechanism. In addition, it is possible to prevent the mowing grass discharged from the discharge duct from flowing and accumulating on the upper surface side of the bottom cover plate, and the mowing grass from the discharge duct can be reliably and smoothly discharged to the ground.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings (FIGS. 1 to 23). FIG. 1 is a side view of a lawn mower according to the embodiment, FIG. 2 is a plan view of FIG. 1, FIG. 3 is a perspective view of the grass collecting box removed from FIG. FIG. 5 is a cross-sectional view taken along the line IV-IV in FIG. 4, FIG. 6 is a perspective view showing a lift mechanism constituting the grass collection discharging mechanism, and FIG. 7 is an enlarged view of the main part of FIG. FIG. 8 is a perspective view of the grass collection box as viewed from diagonally forward at the maximum raised position, FIG. 9 is a perspective view of the grass collection box as viewed from diagonally rearward at the maximum raised position, and FIG. 10 shows the first state of the grass cutting discharge operation. FIG. 11 is a diagram showing a second state of the cutting grass discharging operation, FIG. 12 is a diagram showing a third state of the cutting grass discharging operation, FIG. 13 is a diagram showing a fourth state of the cutting grass discharging operation, and FIG. FIG. 15 is a hydraulic circuit diagram of a lawn mower, and FIG. 16 is a lifting operation lever and an opening / closing operation. FIG. 17 is a front view showing the mounting structure of the lifting operation lever and the opening / closing operation lever, FIG. 18 is an operation explanatory diagram of the opening / closing operation lever, and FIG. 19 is the operation of the lifting operation lever. FIG. 20 is an electric circuit diagram of the limiting mechanism, FIG. 21 is an electric circuit diagram of the PTO regulating mechanism, FIG. 22 is a side view showing the state of the unloading work, and FIG. 23 is a partially omitted front view of the traveling machine body. .

(1). Outline of Lawn Mower In these drawings, reference numeral 1 denotes a riding lawn mower. The lawn mower 1 has a traveling machine body 2 constituted by a pair of left and right side frames 3 extending in the front-rear direction. The airframe 2 is supported by a pair of left and right front wheels 5 that are in contact with the ground 4 and a pair of left and right rear wheels 6 that are also in contact with the ground 4, and the traveling airframe 2 has an upper surface in order from the front. An engine 7, a steering handle 8, and a steering seat 9 are provided, and a bonnet cover 10 that removably covers the engine 7, a step base 11 for the steering seat 9, and a fender 12 that covers both the rear wheels 6 are provided. ing. In this case, when the operator sitting on the control seat 9 rotates the control handle 8, a hydraulic torque generator 137 (see FIG. 15) for power steering, which will be described later, operates according to the operation amount (rotation amount). The steering angle (steering angle) of the left and right front wheels 5 is changed.

  Below the control seat 9, a mission case 61 having a hydrostatic (HST type) continuously variable transmission 95, which will be described later, is disposed. In the embodiment, the rear portions of the left and right side frames 3 are front, rear, rear, and high inclined portions, and the mission case 61 is supported by both the inclined portions. The transmission case 61 is configured to travel forward or backward by appropriately shifting the power from the engine 7 and transmitting it to the left and right rear wheels 6.

  On the lower surface of the traveling machine body 2, a rotary lawn mowing mechanism 13 is configured such that the turfgrass on the ground 4 is trimmed to a portion between the front wheel 5 and the rear wheel 6 by driving with power transmitted from the engine 7. Is provided so as to be able to move up and down, and a discharge duct 14 that discharges the grass cut by the rotary lawn mowing mechanism 13 toward the rear of the traveling machine body 2 is provided between the rear wheels 6. It is provided so as to extend rearward.

  As shown in FIGS. 1 and 2, a rope hook 15 formed by bending a metal rod into a semicircular loop or the like is provided on the outer surface of the center portion of the rear wheels 6. When the lawn mower 1 is transported on a trailer or the like, it is detachably attached by simultaneous fastening with a plurality of bolts 15a for detachably attaching the hub at the center of the axle to the axle. A rope or chain for fixing the rear portion of the lawn mower 1 to a trailer or the like can be hung on the rope hook 15.

  The rope hook 15 is not limited to a loop shape, but may be a hook shape. However, when it is configured as a semicircular loop shape as shown, grass or the like is wrapped around it. There is an advantage that rigidity can be improved. The rope hook 15 having such a structure can be provided on both front wheels 5 instead of the both rear wheels 6 or on both front wheels 5 and both rear wheels 6.

  At the rear of the lawn mower 1, a grass collection mechanism 16 is mounted so as to collect and lift the grass that is discharged rearward from the discharge duct 14, as will be described in detail later. A weight 17 is attached to the front portion of the lawn mower 1 to balance the front and rear weight with respect to the grass collecting / discharging mechanism 16.

  A fuel tank 62 for supplying fuel to the engine 7 is mounted on the rear end portions of the inclined portions in the left and right side frames 3. An oil tank 63 for supplying hydraulic oil to the hydrostatic continuously variable transmission 95 of the mission case 61 and the like is mounted outside the inclined portion of the right side frame 3. A battery 64 used for starting the engine 7 and the like is mounted on the outer side of the inclined portion of the left side frame 3 (on the side opposite to the oil tank 63 with the fuel tank 62 interposed).

(2). Next, a power transmission system of the lawn mower 1 will be described with reference mainly to FIGS. 1 and 2.

  In the lawn mower 1 of the embodiment, a two-wheel drive system that distributes a part of the rotational power of the engine 7 to the left and right rear wheels 6 is adopted. That is, a part of the rotational power of the engine 7 is transferred from the rear end portion of the output shaft 65 protruding forward and backward outward from the engine 7 to the propulsion shaft 66 having universal joints at the front and rear ends, and to the front part of the transmission case 61. The transmission is transmitted to the transmission case 61 via the traveling transmission relay case 67 and the endless input belt 68. Then, the horizontal left and right rear wheel drive shafts 69 projecting left and right outwardly from the mission case 61 are transmitted to the left and right axles on the rear side of the traveling machine body 1 via the left and right endless rear wheel drive chains 70. . As a result, the left and right rear wheels 6 attached to the left and right axles are rotationally driven.

  On the other hand, the other rotational power of the engine 7 is transmitted from the front end portion of the output shaft 65 to a PTO shaft 72 rotatably disposed below the engine 7 via an endless PTO transmission belt 71 for transmitting PTO power. Is done. Next, power is transmitted from the PTO shaft 72 to a mower gear box 74 disposed on the right side frame 3 of the upper surface of the lawn mowing mechanism 13 through an intermediate shaft 73 having universal joints at both front and rear ends. Is done. As a result, a pair of left and right cutting blades (not shown) constituting the lawn mowing mechanism 13 are driven to rotate, and the mowing grass is removed from the left and right sides of the lawn mowing mechanism 13 while cutting the turf grass and the like planted on the ground with these two cutting blades. They are collected at the center of the width and discharged to the discharge duct 14.

  In the embodiment, a PTO clutch 163 as clutch means is disposed between a drive pulley 161 fixed to the front end portion of the output shaft 65 and a driven pulley 162 fixed to the front end portion of the PTO shaft 72 ( (See FIG. 23). The PTO clutch 163 is of a belt tension type in which power from the engine 7 is interrupted by tensioning / relaxing an endless PTO transmission belt 71 wound around the drive pulley 161 and the driven pulley 162. In FIG. 23, the bonnet cover 10 is not shown for convenience of explanation.

  The PTO clutch 163 is interlocked and connected to a PTO clutch motor (not shown) as a connection actuator via a connection link mechanism 165 and a PTO clutch wire 166. In this case, the connection link mechanism 165 and the endless PTO transmission belt 71 are tensioned (see the two-dot chain line state in FIG. 23) or loosened (see the solid line state in FIG. 23) by driving the PTO clutch motor. The power transmission from the output shaft 65 to the PTO shaft 72 is interrupted by turning the PTO clutch 163 around the pivot shaft 164 at the lower end through the PTO clutch wire 166 and turning it.

(3). Next, the structure of the grass collection discharge mechanism 16 will be described with reference to FIGS.

  The grass collection discharge mechanism 16 discharges the grass collection box 18 having an opening 18a facing the rear end of the discharge duct 14 on the front surface and the grass collection box 18 from the discharge duct 14 at a lowered position. There is provided a lift mechanism 19 configured to reciprocate up and down between a forward-facing posture for accepting cut grass (a posture in which the front side is opened) and a high-lifted state in the forward-facing posture.

(3-1). Details of the grass collection box The grass collection box 18 of the grass collection and discharge mechanism 16 surrounds both the left and right side surfaces and the upper surface with a side plate 18b and a ceiling plate 18c made of a breathable plate such as a perforated plate (punching plate) or a wire mesh. On the other hand, the bottom surface and the rear surface of the grass collection box 18 are opened. The open bottom surface of the grass collection box 18 is a bottom cover plate 20 that can be opened and closed. The rear surface that is also opened is the rear cover plate that can be opened and closed. 21 is configured to be closed.

  The bottom cover plate 20 is pivotally attached to a lower end of a bracket member 22 fixed to the outside of the left and right side plates 18b of the grass collection box 18 by a pivot pin 23. As shown in FIG. 5, the bottom lid plate 20 is a perforated plate (punching plate) or a thin metal plate having a breathability, such as a metal mesh, which is obliquely upward at a relatively gentle angle from the front end toward the rear. It is said that the inclined portion 20a and the vertical portion 20b bent downward from the rear end of the inclined portion 20a are repeatedly provided a plurality of times so that the rigidity is increased by folding the inclined portion 20a into a sawtooth cross section having a low height. It is configured.

  The position of the pivot pin 23 is shifted from the center position between the front end and the rear end of the bottom cover plate 20 to the rear end by an appropriate dimension at a position in front of the rear end of the bottom cover plate 20. It is located at the site. Therefore, the bottom cover plate 20 is in contact with the upper surface of the lateral member 39 that connects the lower ends of the left and right side plates 18b of the grass collection box 18 with a weight in front of the pivot pin 23 in a normal state. Then, all open bottoms in the grass collection box 18 are closed (closed), but when an external force acts downward on the rear end, the front end jumps up around the pivot pin 23. Thus, it is configured to open and rotate.

  On the other hand, the rear cover plate 21 is also made of a breathable plate such as a perforated plate (punching plate) or a wire mesh, and pin shafts are provided on the outer side surfaces of the left and right side plates 18b of the grass collecting box 18 on the left and right sides thereof. A state in which the rear surface opened in the grass collection box 18 is closed and jumped up from the rear surface by being rotatably connected to a pair of upper and lower links 24 and 25 that are pivotally attached to 24a and 25a. The double-acting type in which the opening / closing operation is mounted between the bracket member 22 and the lower link 25 of the pair of upper and lower links 24, 25. The opening / closing hydraulic cylinder 26 is used.

  A flexible pair of left and right metal wires 27 or a chain as an example of linkage means disposed in the grass collection box 18 between the rear lid plate 21 and the front end portion of the bottom lid plate 20. When the rear cover plate 21 jumps and pivots so as to open the rear surface of the grass collection box 18 by the piston projecting motion in the opening / closing hydraulic cylinder 26, the metal wire 27 is attached thereto. The bottom cover plate 20 is rotated so that the front end of the bottom cover plate 20 jumps up while the rear end thereof is lowered to open the bottom surface of the grass collection box 18, and the rear cover plate 21 is connected to the hydraulic cylinder 26 for opening and closing. When returning to the state in which the rear surface of the grass collection box 18 is closed by the backward movement of the piston, the bottom cover plate 20 returns to the state in which the bottom surface of the grass collection box 18 is closed by the weight of the front side in conjunction with this. It is configured.

  When the flexible member is the metal wire 27 as described above, both ends of the metal wire 27 are rotated around the bottom lid plate 20 and the rear lid plate 21 by pins 27a and 27b. When movably connected, the metal wire 27 is twisted against its elasticity by an appropriate angle (for example, 90 to 180 degrees) around its longitudinal axis, and in this state, the pins 27a, It is configured to be coupled at 27b.

  As a result, when the bottom cover plate 20 and the rear cover plate 21 are in a closed state, the portion of the metal wire 27 that is slackened in the middle is twisted, as shown in FIG. Since it can be maintained in contact with the upper surface of the bottom cover plate 20, it is possible to prevent the metal wire 27 from interfering when the mowing grass is received in the grass collection box 18.

  In this case, as another embodiment, either one of the upper and lower links 24, 25 serving as an opening / closing mechanism for the rear cover plate 21 or the opening / closing hydraulic cylinder 26 on both outer sides of the grass collection box 18. By interlocking and connecting the bottom cover plate 20, the bottom cover plate 20 can be configured to open and rotate in conjunction with the opening operation of the rear cover plate 21.

  At the front portion of the bottom cover plate 20, a bottom guide plate 28 is provided for smoothly guiding the cut grass that is discharged rearward from the rear end of the discharge duct 14 without spilling it into the grass collection box 18. As shown in FIGS. 4, 9, 11, and 12, in a state where the bottom cover plate 20 is closed, the bottom guide plate 28 is discharged from the front opening 18 a (the cut grass receiving port) of the grass collection box 18 to the discharge duct 14. Projecting forward toward The front end portion of the bottom guide plate 28 faces the rear end portion of the discharge duct 14 in a state where the grass collection box 18 is in a lowered position (see FIGS. 1 and 10) for receiving cut grass and the bottom cover plate 20 is closed. For this reason, the bottom guide plate 28 blocks the bottom side portion between the rear end discharge port of the discharge duct 14 and the front opening 18 a of the grass collection box 18.

  In this case, the bottom guide plate 28 rotates integrally with the bottom cover plate 20 using the pivot pin 23 as a rotation fulcrum. In the embodiment, a configuration is adopted in which the bottom cover plate 20 is rotated so as to jump up its front end and lower its rear end, thereby opening the bottom surface of the grass collection box 18. Therefore, the bottom guide plate 28 and the front opening of the grass collection box 18 are arranged so that the bottom guide plate 28 enters the grass collection box 18 and the bottom cover plate 20 can be opened and rotated large (to a substantially vertical posture). 18a is formed in a shape that does not interfere with each other in the course of opening and closing rotation of the bottom cover plate 20.

  That is, in the side view of FIG. 14, the turning radius D (the distance from the pivot pin 23 to the front end of the bottom guide plate 28) of the front end portion of the bottom guide plate 28 is the same as that in the grass collection box 18. It is set smaller than the distance L to the upper edge of the front opening 18a (D <L). The left-right width dimension of the bottom guide plate 28 is set smaller than the left-right inner dimension of the front opening 18a in the grass collection box 18 (see FIG. 4). For this reason, in the course of opening and closing rotation of the bottom cover plate 20, the bottom guide plate 28 can smoothly enter the grass collection box 18 from the front without being caught by the peripheral edge of the front opening 18 a in the grass collection box 18.

  The bottom guide plate 28 of the embodiment includes a bottom plate 28 a that can abut on the foremost lateral member 39 in the grass collection box 18, and left and right guide side plates 28 b that are close to the inner surfaces of the left and right side plates 18 b in the grass collection box 18. It is formed in an upward U-shape when viewed from the front. The rear end portions of the left and right guide side plates 28b extend to the upper front portion of the bottom cover plate 20.

  With this configuration, when the grass collection box 18 is in the lowered position and the bottom cover plate 20 is closed, the bottom between the rear end discharge port of the discharge duct 14 and the front opening 18a of the grass collection box 18 is provided. Since the side portion is surrounded by the upward U-shaped bottom guide plate 28, it is possible to reliably suppress spilling of the grass from the joint portion when the grass is collected in the grass collection box 18. Moreover, since the rear end portions of the left and right guide side plates 28b are extended to the front surface front portion of the bottom cover plate 20, the attachment strength (rigidity) of the bottom guide plate 28 to the bottom cover plate 20 is also high.

(3-2). Details of Lift Mechanism The lift mechanism 19 in the grass collection / discharge mechanism 16 is configured as shown in FIGS. That is, the lift mechanism 19 includes a mast member 29 disposed on each of the left and right sides sandwiching the grass collection box 18, a double-acting lifting hydraulic cylinder 30 as a lifting actuator, and a pair of upper and lower lift links 31, 32, both the mast members 29 are made of square pipes having a hollow cross section and extend in the vertical direction, and are detachably attached to the rear portion of the traveling machine body 2 by fastening bolts 59 or the like at the lower end 29a. In addition, the plurality of cross members 33 are connected to each other, and are formed in a cross beam shape when viewed from the traveling direction of the lawn mower 1.

  The both mast members 29 can be attached to the traveling machine body 2 in a detachable state by fastening with the bolts 59 to the rear ends of the side frames 3 in the traveling machine body 2 and the rear ends of the side frames 3. It is configured to be performed by fastening with a bolt 59 to the rear wheel support frame 3a extending downward from the front.

  Further, both the mast members 29 have their upper end portions 29b in front of the lower end portion 29a, which is a mounting portion for the traveling machine body 2, as appropriate in a side view (FIGS. 1, 3, 4, and 6). The upper bracket member 34 having a rearward groove-shaped cross section is fixed to the rear surface of the upper end portion 29b of both the mast members 29 by welding or the like. On the other hand, a lower bracket member 35 is fixed to the lower ends of both the mast members 29 so as to protrude rearward.

  The upper ends of the pair of upper and lower lift links 31, 32 are inserted into the upper bracket member 34 in the upper bracket member 34 at the upper end portion 29 b of the both mast members 29. It is pivotally attached by lift pins 36 and 37 detachably inserted so as to penetrate the member 34.

  In other words, the lift pins 36 and 37 with respect to the base ends of the lift links 31 and 32 have a structure that is supported at both ends with respect to the upper bracket member 34, so that the rigidity and durability of the support by the lift pins 36 and 37 are increased. In addition, since the base ends of the lift links 31 and 32 are inserted into the grooves in the upper bracket member 34, the lift links 31 and 32 can be swung in the lateral direction. Can be reliably reduced.

  In addition, the upper and lower mast members 29 are bent forward so that the upper end portion 29b is positioned forward of the lower end portion 29a by a dimension E as appropriate. Positions of the lift pins 36 and 37 at the ends along the front-rear direction of the traveling machine body 2 are located in front of the traveling machine body 2 side by the appropriate dimension E as compared with the case where the mast member 29 is configured to be straight. Therefore, when the grass collection box 18 is moved up to the maximum, as will be described later, the maximum rising height can be increased by the appropriate dimension E, and the maximum height can be increased. The lengths of the lift links 36 and 37 required to obtain the height can be shortened by the appropriate dimension E.

  In addition, since the point of action of the support load on the traveling machine body 2 in the grass collection box 18 is positioned forward (the traveling machine body 2 side) by the appropriate dimension E, the rear load on the traveling machine body 2 is reduced. Can do.

  On the other hand, the tip of the upper link 31 of the pair of upper and lower lift links 31, 32 is pivotally attached to the bracket member 22 fixed to the outside of the left and right side plates 18 b of the grass collection box 18 by a pin 38. The tip of the lower link 32 of the pair of upper and lower lift links 31, 32 is rotated with respect to the lower ends of the left and right side plates 18 b of the grass collection box 18 by a pivot pin 23 with respect to the bottom cover plate 20. It is pivotally attached.

  A pivot pin for the grass collection box 18 at the tip of the lower link 32 of the pair of upper and lower lift links 31, 32 is combined with a pivot pin 23 for the bottom cover plate 20 in the grass collection box 18. However, it goes without saying that the pivot pin for the grass collection box 18 at the tip of the lower link 32 and the pivot pin 23 for the bottom cover plate 20 can be configured separately.

  A lever body 40 is pivotally attached to each inner surface of the lower bracket member 35 at the lower end of both the mast members 29 by means of a pin 41. The two lever bodies 40 are located between the two lever bodies 40. The lever members 40 are integrally connected to each other so as to rotate at the same time. The base end of the lifting hydraulic cylinder 30 is freely rotatable by a cylinder pivoting pin 43. It is connected to.

  Further, when both lever bodies 40 are rotated rearward, the cylinder pivot pin 43 is further rotated backward with respect to the stopper portion 44 at the rear end of the lower bracket member 35. It is the structure that touches so as to prevent.

  In this case, instead of adopting a configuration in which the cylinder pivot pin 43 contacts the stopper portion 44, another stopper member provided on the lever body 40 contacts the stopper portion 44. It may be configured to do.

  In addition, the lever body 40 is pivoted backward from the bottom surface of the lower bracket member 35 in a state where the lever body 40 pivots backward and the cylinder pivot pin 43 contacts the stopper portion 44. An outrigger 45 that protrudes downward, and a bumper body that protrudes rearward to substantially the same position as the stopper portion 44 in the lower bracket member 35 or protrudes further rearward than the stopper portion 44. 46 is provided.

  Further, when the lever body 40 is rotated forward, the lever bodies 40 are further rotated forward with respect to the lower bracket member 35 or the mast member 29 (further forward from the storage position). A stopper piece 47 is provided so as to prevent the rotation). Accordingly, the left and right lever bodies 40 and the outrigger 45, the bumper body 46, and the stopper piece 47 provided on each of the left and right lever bodies 40 are configured to change their postures integrally around the pin 41 as a rotation center.

  And the front-end | tip of the said both raising / lowering hydraulic cylinder 30 is connected with the pin 48 with respect to the lower link 32 among the said upper-lower paired lift links 31, 32, and the said upper-lower paired lift links 31, 32 are connected. When the grass collecting box 18 is rotated in the up and down direction by the lifting and lowering hydraulic cylinders 30, the grass collection box 18 has a forward attitude for receiving the mowing grass discharged from the discharge duct 14 in the lowered position, and the forward attitude. It is configured to reciprocate and move up and down in a state where it is lifted up as it is.

  That is, while the lifting-up hydraulic cylinder 30 lifts the grass collection box 18 in the forward posture by the piston projecting motion, the piston-moving motion in the lifting hydraulic cylinder 30 moves the grass collection box 18 in the forward posture to the original position. It is configured to descend.

  Of the pair of upper and lower lift links 31, 32, the lower link 32 has the upper end portion 29 b of both the mast members 29 or the first bracket member 34 when the grass collection box 18 is lifted high. The hook-shaped locking means 49 is provided so as to be detachably engaged so as to prevent the downward rotation. The hook-shaped locking means 49 is provided on the upper link 31 or the mast members 29 of the both mast members 29. You may provide in the upper end part 29b or the 1st bracket member 34 side.

  Further, between the lift links 31 and 32 on the right side and the lift links 31 and 32 on the left side, the horizontal members 50 and 51 are interposed at the upper end portions so that these links rotate simultaneously. Are connected.

  Furthermore, a portion of the lawn mower 1 that can be reached from the control seat 9 is provided with a PTO operation lever 52 as a PTO operation body for turning the rotary lawn mowing mechanism 13 on and off. An open / close operation lever 53 is provided for switching the open / close hydraulic cylinder 26 to an open position where the piston protrudes, a closed position where the piston moves backward, and a neutral position where the piston operation stops in the middle. There is provided an elevating operation lever 54 for switching the hydraulic cylinder 30 to a raised position where the piston protrudes, a lowered position where the piston moves backward, and a neutral position where the piston operation stops in the middle.

  When the PTO operation lever 52 is operated under a predetermined condition described later (forward tilt operation), the PTO clutch 163 (see FIG. 23) is engaged by the driving of the PTO clutch motor to actuate the endless PTO transmission belt 71, When the cutting operation (backward tilting operation) is performed, the PTO clutch 163 is turned off by driving the PTO clutch motor to loosen the endless PTO transmission belt 71. The PTO operation lever 52 is provided with a PTO entering sensor 171 (see FIG. 21) as a PTO detecting means that enters and operates when the lever is operated. Whether the PTO operation lever 52 is in the input operation position (power connection position) can be detected by the ON / OFF operation of the PTO input sensor 171.

(4). Hydraulic Circuit Structure of Lawn Mower Next, the hydraulic circuit 91 structure of the lawn mower 1 will be described with reference to FIG.

  The hydraulic circuit 91 of the lawn mower 1 is composed of a charging hydraulic pump 92 and a variable displacement type hydraulic pump 93 that are operated by the rotational force of the engine 7, and a high-pressure hydraulic oil discharged from the transmission hydraulic pump 93. And a constant displacement type shifting hydraulic motor 94 that operates. The transmission hydraulic pump 93 and the transmission hydraulic motor 94 constitute a hydrostatic continuously variable transmission 95. The hydrostatic continuously variable transmission 95 (the transmission hydraulic pump 93 and the transmission hydraulic motor of the embodiment). 94) is built in the mission case 61.

  The transmission hydraulic pump 93 and the transmission hydraulic motor 94 are connected to each other on the suction side and the discharge side via a closed loop oil passage 96. By adjusting the angle of the swash plate 97 of the shift hydraulic pump 93 driven by the power of the engine 7 by a shift pedal 81 (see FIGS. 1, 2 and 15) disposed at the lower right side of the steering handle 8. The rotational speed of the left and right axles (axle on the rear side of the traveling machine body 1) driven by the power from the transmission hydraulic motor 94 is changed. As a result, the rotational speed of the rear wheels 6 attached to the left and right axles, and thus the vehicle speed (traveling speed) of the traveling machine body 1 is changed.

  As shown in FIG. 15, the hydraulic circuit 91 described above includes a relief valve, an oil filter, a check valve, and the like. The suction side of the charging hydraulic pump 92 is connected to a strainer 99 in the oil tank 63 via a low-pressure charging oil passage 98. A high-pressure charge oil passage 102 having a supply relief valve 100 and a return relief valve 101 is connected to the discharge side of the charge hydraulic pump 92. The high-pressure charge oil passage 102 is connected to the closed-loop oil passage 96 through a relief valve 100 for replenishment, a check valve 103 for forward replenishment, a check 104 valve for reverse replenishment, and the like.

  Accordingly, during the operation of the engine 7, the working oil from the charging hydraulic pump 92 is always replenished to the closed loop oil passage 96. Further, if there is excess hydraulic oil in the charge oil passages 98 and 102 to be supplied from the charge hydraulic pump 92 to the closed loop oil passage 96, the hydraulic oil in the charge oil passages 98 and 102 passes through the return relief valve 101. Thus, the oil tank 63 is returned.

  On the other hand, in the closed loop oil passage 96, between the suction side of the transmission hydraulic pump 93 and the discharge side of the transmission hydraulic motor 94, and between the suction side of the transmission hydraulic motor 94 and the discharge side of the transmission hydraulic pump 93. A bypass valve 105 for short-circuiting is connected. When the bypass valve 105 is switched to a state in which the closed loop circuit 96 is not short-circuited (the state of the bypass valve 105 shown in FIG. 15) by the operation of the bypass switching lever 106 provided in association with the bypass valve 105, the shift hydraulic pressure The pump 93 and the transmission hydraulic motor 94 communicate with the traveling drive state via the closed loop oil passage 96, and the rear wheel 6 is driven by the rotational power of the engine 7.

  On the other hand, when the bypass valve 105 is switched to a state in which the closed loop circuit 96 is short-circuited by the operation of the bypass switching lever 106, the transmission hydraulic motor 94 is held in a free rotation state (a state in which it rotates with no load). . For example, when the above-described switching operation is performed when the rear wheel 6 cannot be driven due to a failure such as running out of fuel in the fuel tank 62, the hydrostatic continuously variable transmission 95 in the mission case 61 is Since it is held in a no-load state, the operator can push and move the traveling machine body 1.

  The charging hydraulic pump 92 includes an elevating hydraulic valve 107 for supplying hydraulic oil to the double-acting elevating hydraulic cylinder 30, a malfunction prevention check valve 108, and an elevating hydraulic valve 107 (elevating hydraulic cylinder 30. ) Is connected via an electromagnetic discharge valve 135 for adjusting and controlling the supply of hydraulic oil to. The electromagnetic discharge valve 135 is configured to automatically perform switching operation by driving of an electromagnetic discharge solenoid 136 corresponding to detection signals (on / off signals) of various sensors 142 to 145 (see FIG. 20) described later. An open / close hydraulic valve 109 for supplying hydraulic oil to the double-acting open / close hydraulic cylinder 26 is connected to the tank port of the lift hydraulic valve 107. The electromagnetic discharge valve 135 is also connected to an oil passage between the opening / closing hydraulic valve 109 and a torque generator 137 (details will be described later) on the downstream side thereof.

  When the electromagnetic discharge valve 135 supplies hydraulic fluid to the lifting hydraulic valve 107 (the state of the electromagnetic discharge valve 135 shown in FIG. 15, hereinafter referred to as the supply state), the lift control lever 54 is operated. When the raising / lowering hydraulic valve 107 is switched, the raising / lowering hydraulic cylinder 30 expands / contracts, and the grass collection box 18 has a lowered position for receiving the cut grass discharged from the discharge duct 14 in a forward attitude, and a forward attitude. It will move up and down to the raised position when it is lifted high.

  When the opening / closing hydraulic valve 109 is switched by operating the opening / closing operation lever 53, the opening / closing hydraulic cylinder 26 is expanded and contracted, and the rear cover plate 21 closes the rear surface opened in the grass collection box 18. It opens and closes to the state of opening so as to jump up from the rear surface. In addition, with the opening / closing operation of the rear cover plate 21, the bottom cover plate 20 is rotated such that the front end jumps up and the rear end is lowered by pulling the metal wire 27, and the bottom surface of the grass collection box 18 is opened. The front and rear weights open and close the bottom of the grass collection box 18 in a closed state.

  When the electromagnetic discharge valve 135 stops supplying hydraulic fluid to the lifting hydraulic valve 107 (hereinafter referred to as supply stop state), the hydraulic fluid from the charging hydraulic pump 92 via the electromagnetic discharge valve 135 moves up and down. Instead of being sent to the hydraulic cylinder 30 for operation, the hydraulic valve 109 for opening and closing, and therefore only to the hydraulic cylinder 26 for opening and closing are supplied. Accordingly, in this state, only the rear cover plate 21 and the bottom cover plate 20 can be opened and closed by operating the opening / closing operation lever 53. Even if the lifting operation lever 54 is operated, the lifting / lowering hydraulic cylinder 30 and the grass collection box 18 are not moved. Does not move up and down.

  In the embodiment, when the electromagnetic discharge valve 135 is in a supply stop state, when the opening / closing operation lever 53 is operated toward the open position, the bottom cover plate 20 that opens and rotates in conjunction with the rear cover plate 21 is inclined rearward and downward. The open / close hydraulic cylinder 26 is configured to operate until it is in a tilted posture (see FIG. 22). The opening / closing hydraulic valve 109 is automatically set to the neutral position and the opening / closing hydraulic cylinder 26 is deactivated. As a result, the bottom cover plate 20 is released and held in an inclined posture. Further, in the embodiment, when the bottom cover plate 20 is released and in an inclined posture, the front end portion (front end portion) of the bottom guide plate 28 is made to face the upper portion of the rear end discharge port (mowing grass discharge port) in the discharge duct 14 ( It is configured to be close).

  When the bottom cover plate 20 is released and held in an inclined position, the bottom opening of the grass collection box 18 is opened. Therefore, when the lawn mowing mechanism 13 is driven in this state, the mowing grass cut by the lawn mowing mechanism 13. Is introduced into the grass collection box 18 through the discharge duct 14 and received on the back surface side (lower surface side) of the bottom cover plate 20. Then, the mowing grass is smoothly guided (guided) rearward and downward along the slope of the bottom cover plate 20 obliquely downward, and is spread from the bottom opening of the grass collection box 18 to the ground.

  That is, in the embodiment, since the bottom cover plate 20 is configured to be openable in a state where the grass collection box 18 is in the lowered position, the bottom opening of the grass collection box 18 in the lowered position can be opened. 2. With the grass collection box 18 attached to the rear part of the two, it is possible to easily carry out the work of laying on the ground without collecting the cut grass.

  Further, in the embodiment, the lawn mower 1 can be moved by simply switching the opening / closing posture of the bottom cover plate 20 between the closed posture (the state in which the bottom opening is closed, see FIGS. 1 and 10) and the loosely inclined posture. It can be used for cut grass collection work (work for collecting the cut grass in the grass collection box 18) or for the release work. That is, the operator can easily switch from the cutting and collecting operation to the releasing operation or vice versa without changing the grass collecting box 18 and the releasing cover as in the conventional case. Although 1 is a highly versatile one that can be used for the mowing collection work or the unloading work, it is easy to handle with a low work burden on the operator.

  Moreover, the opening operation of the bottom cover plate 20 in the embodiment is configured to rotate and open so that the bottom guide plate 28 side jumps up into the grass collection box 18, and the grass collection box 18 is in the lowered position. Since the bottom cover plate 20 that is opened and rotated in the state is held in a discharge inclined posture with the front end portion of the bottom guide plate 28 facing the upper portion of the rear end discharge port in the discharge duct 14, The side (lower surface side) serves as a guide surface that guides the mowing grass toward the ground. That is, the bottom cover plate 20 can function as a deflector for changing the discharge destination of the cut grass, and the cut grass discharged from the discharge duct 14 can be smoothly discharged to the ground by the guide action (deflector action) of the bottom cover plate 20. .

  In this case (when the bottom cover plate 20 is in a tilted position), the front end portion of the bottom guide plate 28 faces the upper portion of the rear end discharge port of the discharge duct 14. The gap between the upper portion and the upper end of the rear end discharge port in the discharge duct 14 is narrow, and there is little possibility that the mowing grass discharged from the discharge duct 14 will leak (escape) to the surface side (upper surface side) of the bottom cover plate 20. Therefore, there is also an advantage that the mowing grass from the discharge duct 14 can be efficiently discharged to the ground without being accumulated on the surface side of the bottom cover plate 20.

  On the other hand, a power steering torque generator 137 for steering the front wheel 5 using a large hydraulic pressure generated by operating the steering handle 10 is connected to the tank port of the dump valve 109. . The torque generator 137 is connected to the return relief valve 101 via a parallel line filter 110 and a relief valve 111. Accordingly, the hydraulic oil from the torque generator 137 is returned to the oil tank 63 via the line filter 112. The torque generator 137 includes a control valve that is switched by turning the steering handle 10 and a hydraulic pump that is operated by the control valve. The torque generator 137 uses the rotational force of the hydraulic pump to move the front wheel 5. It is configured to change direction.

  As is clear from FIG. 15, the lifting hydraulic valve 107, the opening / closing hydraulic valve 109, and the torque generator 137 are connected in series to the charging hydraulic pump 92. For this reason, when the electromagnetic release valve 135 is in the supply state, the open / close hydraulic cylinder 26 and the torque generator 137 are driven while the elevating hydraulic cylinder 30 is extended and contracted by the switching operation of the elevating hydraulic valve 107. do not do.

  Further, when the electromagnetic release valve 135 is in the supply state, the torque generator 137 is not driven while the open / close hydraulic cylinder 26 is extended and contracted by the switching operation of the open / close hydraulic valve 109. Further, when the electromagnetic release valve 135 is in the supply state, the torque generator 137 is driven unless both the lifting hydraulic cylinder 30 and the opening / closing hydraulic cylinder 26 are driven.

  That is, when the electromagnetic discharge valve 135 is in the supply state, the lifting hydraulic valve 107, the opening / closing hydraulic valve 109, and the torque generator 137 are configured to be driven with priority in this order.

(5). Next, the mounting structure of the lifting / lowering operation lever 54 and the opening / closing operation lever 53 will be described with reference to FIGS. 16 to 19.

  A hydraulic pipe (not shown) is connected to the hydraulic pump 92 for charging, the lifting hydraulic cylinder 30 and the opening / closing hydraulic cylinder 26 in the hydraulic unit case 116 (see FIG. 2) disposed diagonally to the right of the control seat 9. And a hydraulic valve unit body 115 having a lifting hydraulic valve 107 and an opening / closing hydraulic valve 109 is incorporated.

  An elevation operation lever 54 and an opening / closing operation lever 53 are attached to the front surface of the hydraulic valve unit body 115 via a lever bearing 117 so as to be rotatable in the vertical direction. The lifting operation lever 54 protrudes substantially horizontally toward the front of the hydraulic valve unit body 115 with the lifting hydraulic valve 107 in a neutral state. When the elevating operation lever 54 is turned up and down, the elevating hydraulic valve 107 is switched to the ascending side or the descending side, and the elevating hydraulic cylinder 30 is driven to extend and contract. When the opening / closing operation lever 53 is turned up and down, the opening / closing hydraulic valve 109 is switched to the opening side or the closing side, and the opening / closing hydraulic cylinder 26 is driven to extend and contract.

  The hydraulic unit case 116 has a lever guide body 118 for guiding the vertical rotation of the operation levers 53 and 54, and a brake pedal 82 (see FIGS. 2 and FIG. 15), the lock arm body 120 interlocked and connected via the brake detection wire 119, and a check arm that restricts the other operation when one of the lift operating levers 53 and 54 is operated. And a body 121. In the embodiment, a lock arm body 120 and a check arm body 121 are pivotally supported by a lever guide body 118 fixed in a hydraulic unit case 116 via a support shaft 122 extending in the front-rear direction so as to be independently rotatable. ing.

  The lock arm body 120 has a generally bowl-like shape when viewed from the front, and the side end portion 120b of the lock arm body 120 that faces the lifting operation lever 54 is engaged with the shaft portion of the lifting operation lever 54 so as to be lifted and engaged. A restriction notch 120a is formed. The check arm body 121 is formed with an elevating check notch 121a that can be hooked and engaged with the shaft portion of the elevating operation lever 54, and an open / close check notch 121b that can be hooked and engaged with the shaft portion of the open / close operation lever 53. In addition, a pair of upper and lower pressure rolls 123 and 124 that can come into contact with the shaft portion of the lift lever 110 are pivotally supported on the check arm body 121 via upper and lower roll shafts 125 and 126. Both the pressure rolls 123 and 124 are arranged separately on both upper and lower sides with the lift restraining notch 121a in the restraining arm body 121 interposed therebetween.

  A connection fitting 130 attached to one end of the brake detection wire 119 is fixed to one end of the lock arm body 120 via a connection pin 129. A stopper for restricting the rotation of the lock arm body 120 in the direction in which the elevating restriction notch 120 a moves away from the lift lever 110 at the other end of the lock arm body 120 opposite to the connecting pin 129 across the support shaft 122. The body 131 is integrally formed.

  The connecting pin 129 is hooked with the other end portion 127 b of a pinch spring-like braking detection spring 127 in which one end portion 127 a is fixed to the front surface of the lever guide body 118. The brake detection spring 127 urges the lock arm body 120 in the rotation direction such that the elevating restriction notch 120a is separated from the elevating operation lever 54 by its elastic urging force. Between the connecting pin 129 and the upper roll shaft 125 of the upper pressure roll 123, a tension spring shape for biasing the check arm body 121 in a turning direction in which the open / close check notch 121b is separated from the open / close operation lever 53. The release spring 128 is mounted.

  The spring force of the brake detection spring 127 is set to be smaller than the spring force of a pedal return spring (not shown) that maintains the brake pedal 82 at the initial position (brake release position). The spring force of the release spring 128 is set to be smaller than the spring force of the brake detection spring 127.

  When the brake pedal 82 is in the initial position where the pedal is not depressed (brake release position), the brake detection wire 119 is pulled by the spring force of the pedal return spring, so that the lock arm body 120 includes the brake detection spring 127. Against the spring force, it rotates in the clockwise direction around the support shaft 122 in FIG. 17, and the elevating restriction notch 120 a is hooked on and engaged with the shaft portion of the elevating operation lever 54. At this time, the check arm body 121 is rotated counterclockwise around the support shaft 122 in FIG. 17 by the spring force of the release spring 128, and the lower pressure roll 124 is moved to the side end 120 b of the lock arm body 120. Abut. In this state, the opening / closing check notch 121b is hooked and engaged with the shaft portion of the opening / closing operation lever 53.

  Therefore, if the brake pedal 82 is not in the depressed position (brake position), any operation of the elevating operation lever 54 and the opening / closing operation lever 53 is prohibited by the lock arm body 120 and the check arm body 121.

  As shown in FIG. 18, when the brake pedal 82 is depressed and the rear wheel 6 is braked, the brake detection wire 119 is loosened, so that the lock arm body 120 is driven by the spring force of the brake detection spring 127. The stopper body 131 is rotated counterclockwise around the support shaft 122 in FIG. 18 until the stopper body 131 comes into contact with the upper surface of the lever guide body 118, and the lifting restriction notch 120 a is detached from the shaft portion of the lifting operation lever 54. At this time, the check arm body 121 is rotated counterclockwise around the support shaft 122 in FIG. 18 by the spring force of the release spring 128, and the open / close check notch 121 b is detached from the shaft portion of the open / close operation lever 53. The upper and lower pressure rolls 123 and 124 are in contact with the shaft portion of the lifting operation lever 54.

  That is, when the rear wheel 6 is braked by depressing the brake pedal 82, the elevating operation lever 54 and the opening / closing operation lever 53 become operable.

  Therefore, as shown in FIG. 18, when the opening / closing operation lever 53 is first turned up and down, the opening / closing operation lever 53 moves to a contact position with the regulating end 121 c or 121 d of the checking arm body 121, and the checking arm is moved. The body 121 is further rotated in the counterclockwise direction around the support shaft 122 shown in FIG. 18, and the elevating check notch 121 a between the upper and lower pressure rolls 123, 124 is hooked and engaged with the shaft portion of the elevating operation lever 54. .

  In this state, even if the up / down operation lever 54 is to be turned up and down, the restriction end 121c or 121d of the check arm body 121 hits the shaft portion of the open / close operation lever 53, and the check arm body 121 rotates in the clockwise direction. Since the engagement between the shaft portion of the elevating operation lever 54 and the elevating check notch 121a is maintained, the elevating operation lever 54 cannot be rotated up and down. That is, when the opening / closing operation lever 53 is turned up and down, the up / down turning operation of the raising / lowering operation lever 54 is prohibited by the cooperative action of the opening / closing operation lever 53 and the check arm body 121.

  On the other hand, as shown in FIG. 19, when the up / down operation lever 54 is first turned up and down, the up / down operation lever 54 presses one pressure roll 123 or 124 against the spring force of the release spring 128, The check arm body 121 is rotated clockwise around the support shaft 122 shown in FIG. 19, and the open / close check notch 121 b is hooked on the shaft portion of the open / close operation lever 53 and engaged.

  Even if the opening / closing operation lever 53 is to be turned up and down in this state, one pressure roll 123 or 124 hits the shaft portion of the lifting operation lever 54 to prevent the check arm body 121 from rotating counterclockwise. Since the engagement between the shaft portion of the opening / closing operation lever 53 and the opening / closing check notch 121b is maintained, the opening / closing operation lever 53 cannot be rotated up and down. That is, in the state where the up / down operation lever 54 is turned up and down, the up / down turning operation of the opening / closing operation lever 53 is prohibited by the cooperative action of the up / down operation lever 54 and the check arm body 121.

  Therefore, if the brake pedal 82 is depressed and the rear wheel 6 is braked, the operator can alternatively rotate the up / down operation lever 54 or the open / close operation lever 53 up and down.

(6). Next, the structure of the limiting mechanism for preventing the grass box 18 from moving up and down due to an erroneous operation of the lifting operation lever 54 will be described with reference to FIG.

  The limiting mechanism 140 of the lawn mower 1 in the embodiment includes a battery 64, a key switch 141 for applying power, and an electromagnetic discharge solenoid 136 of an electromagnetic discharge valve 135. In this case, a key switch 141 and an electromagnetic discharge solenoid 136 are connected to the battery 64 in series. The key switch 141 is configured to be connectable to a starter (not shown) for starting the engine 7.

  Between the key switch 141 and the electromagnetic discharge solenoid 136, an on / off switch type operator sensor 142 that is activated when an operator sits on the control seat 9 and the rear cover plate 21 block the rear opening of the grass collection box 18. An on / off changeover switch type rear cover plate detection sensor 143 that is turned off when in the closed position, and an on / off changeover switch type bottom cover that is turned off when the bottom cover plate 20 closes the bottom opening of the grass collection box 18. A plate detection sensor 144 and an on / off switch type grass collection box sensor 145 that is activated when the grass collection box 18 is in the lowered position are connected in series.

  The rear lid plate detection sensor 143 is provided in association with a pin shaft 24a that pivotally supports the upper link 24 relative to the rear lid plate 21. The bottom cover plate detection sensor 144 is provided in association with a pivot pin 23 that rotatably supports the bottom cover plate 20. The grass collection box sensor 145 is provided behind the discharge duct 14 (on the traveling machine body 2 side, for example, on the lowermost lateral member 33 connecting both the mast members 29), and when the grass collection box 18 is in the lowered position. When the bottom guide plate 28 comes into contact with the grass collection box sensor 145, the grass collection box sensor 145 enters and operates.

  In this configuration, (1) an operator is seated on the control seat 9, (2) (3) the rear cover plate 21 and the bottom cover plate 20 are opened and operated, and (4) the grass collection box 18 is in the lowered position. If all the four conditions are met, the electromagnetic discharge solenoid 136 is switched by the above-described operation of the four sensors 142 to 145, and the hydraulic oil is supplied from the electromagnetic discharge valve 135 to the lifting hydraulic valve 107. Stop. As a result, the hydraulic oil is not sent to the lifting hydraulic cylinder 30, and even if the lifting control lever 54 is operated, the lifting hydraulic cylinder 30 and the grass collection box 18 do not move up and down.

(7). Next, the structure of the PTO restriction mechanism 170 for preventing inadvertent driving of the lawn mowing mechanism 13 will be described with reference to FIG.

  The PTO regulation mechanism 170 of the lawn mower 1 in the embodiment detects the vertical position of the battery 64, the PTO entering sensor 171 as PTO detecting means that operates when the PTO operating lever 52 is entered and operated, and the grass collection box 18. And a lift stroke sensor 172 as an example of the grass collecting detection means, and a motor drive circuit unit 173 for driving a PTO clutch motor (not shown). In this case, a PTO-containing sensor 171, a lift stroke sensor 172, and a motor drive circuit unit 175 are connected to the battery 64 in series.

  The lift stroke sensor 172 detects the vertical position of the grass collection box 18 from the piston protrusion amount (protrusion position) of the lifting hydraulic cylinder 30, and when the piston of the lifting hydraulic cylinder 30 is in the most shortened state, That is, it is configured to operate when the grass collection box 18 is in the lowered position.

  Between the lift stroke sensor 172 and the motor drive circuit unit 175, a bottom cover plate closing sensor 173 and a bottom cover plate discharge sensor 174 as posture detecting means are connected in parallel to each other. The bottom lid plate closing sensor 173 is of an on / off switch type that is turned on when the bottom lid plate 20 is in a closing posture (closed position, see FIGS. 1 and 10) that closes the bottom opening of the grass collection box 18. The bottom cover plate release sensor 174 is of an on / off switch type that is turned on when the bottom cover plate 20 is in the downward inclined posture shown in FIG. These sensors 173 and 174 are provided in association with, for example, the peripheral edge of the bottom opening of the grass collection box 18 and the pivot pin 23 that pivotally supports the bottom cover plate.

  In such a configuration, (1) when the grass collection box 18 is in the lowered position and the bottom cover plate 20 is in the closed position, (2) the grass collection box 18 is in the lowered position and the bottom cover plate 20 is left to be inclined. If either of the conditions is satisfied, if the PTO operation lever 52 is entered and operated, each of the sensors 171, 172, 173 (or 171, 172, 174) described above enters and operates, A current from the battery 64 flows to the motor drive circuit unit 175 via the sensors 171, 172, 173 (or 171, 172, 174). As a result, the PTO clutch motor is driven and the PTO clutch 163 (see FIG. 23) is engaged (power connection state). That is, the driving of the lawn mowing mechanism 13 is allowed only when the grass collection box 18 is in the lowered position and the bottom cover plate 20 is in the closed posture or the inclined posture.

  On the other hand, if the grass collection box 18 is in the raised position or is being raised, the lift stroke sensor 172 is turned off. Therefore, even if the PTO operation lever 52 is turned on, the current from the battery 64 is cut off halfway. As a result, the PTO clutch 163 is turned off (power cut-off state), and the driving of the lawn mowing mechanism 13 is prohibited. Further, if the bottom cover plate 20 is a halfway open posture that is neither a closed posture nor a tilted posture, both the bottom cover plate closing sensor 173 and the bottom lid plate discharge sensor 174 are turned off, so that the PTO operation Even when the lever 52 is turned on, the current from the battery 64 is interrupted in the middle. As a result, the PTO clutch 163 is turned off (power cut-off state), and the driving of the lawn mowing mechanism 13 is prohibited.

  For this reason, for example, even when the lawn mowing mechanism 13 is being driven, even if the operating lever 54 for raising / lowering or the operating lever 53 for opening / closing is accidentally contacted, the PTO clutch 163 is disengaged and the lawn mowing mechanism 13 is automatically driven. Since it stops, it is possible to prevent the grass and pebbles from being inadvertently scattered from the rear end discharge port of the discharge duct 14 to the rear of the traveling machine body 2.

  Further, even if the operator erroneously enters and operates the PTO operation lever 52 when the grass collection box 18 is in the raised position (at the time of the grass cutting operation), the PTO clutch 163 is held in the disconnected state, and the lawn mowing mechanism 13 is In this case as well, it is possible to prevent the grass and pebbles from being inadvertently scattered from the rear end discharge port of the discharge duct 14 to the rear of the traveling machine body 2 in this case.

  Moreover, when the grass collection box 18 is in the lowered position and the bottom cover plate 20 is in the closed position or the inclined position, the driving of the lawn mowing mechanism 13 is allowed, so the lawn mower 1 of the embodiment is used. Needless to say, the grass cutting and release work can be performed without any problems.

  Further, as described above, when the bottom cover plate 20 is in a halfway open posture that is neither a closed posture nor a tilted posture (when it is not a predetermined opening / closing posture), the driving of the lawn mowing mechanism 13 is prohibited. The operator can easily grasp whether or not the lawn mowing mechanism 13 is driven, for example, whether or not the bottom cover plate 20 is in the proper tilting posture during the unloading operation. In addition, it is possible to prevent the mowing grass discharged from the discharge duct 14 from flowing and accumulating on the surface side of the bottom cover plate 20, and the mowing grass from the exhaust duct 14 can be reliably and smoothly discharged to the ground.

(8). Operation Mode of Grass Collection Discharge Mechanism Next, an example of the operation mode of the grass collection discharge mechanism will be described with reference to FIGS. 1 and 10 to 14.

  In the above-described configuration, the grass collection box 18 in the grass collection / discharge mechanism 16 is released from the discharge duct 14 by holding the grass collection box 18 in a lowered position with the bottom cover plate 20 and the rear cover plate 21 closed. In this state, the lawn mower 1 can move forward while driving the rotary lawn mowing mechanism 13 to perform predetermined lawn mowing. The rotary lawn mowing mechanism 13 Mowed grass is collected in the grass collection box 18 through the discharge duct 14 and the bottom guide plate 28.

  When a predetermined amount of mowing grass accumulates in the grass collection box 18, the mowing operation and forward traveling are stopped, and the mowing grass discharge operation from the grass collection box 18 is started. In the discharging operation, first, the lifting / lowering hydraulic cylinders 30 are operated so that the piston protrudes by operating the lifting / lowering operation lever 54 to the raised position so as to lift the grass collection box 18. .

  Then, first, the lever body 40 at the base end of both the lifting and lowering hydraulic cylinders 30 is rotated rearward so that the pivot pin 43 comes into contact with the stopper portion 44, as shown in FIG. The outrigger 45 provided on the lever body 40 protrudes so as to approach the ground 4 and can be prevented from tilting backward so that the front portion of the lawn mower 1 is lifted.

  That is, when discharging the cut grass received in the grass collection box 18, the outrigger 45 protrudes so as to be close to the ground at any time between the start of lifting the grass collection box 18 and the middle of lifting, It is possible to reliably reduce the risk that the traveling machine body 2 tilts backward while the grass collection box 18 is lifted high.

  Moreover, since the protrusion of the outrigger 45 is performed at any time between the start of lifting of the grass collection box 18 and the middle of lifting, it is ensured that the presence of the outrigger 45 hinders normal travel in the lawn mower 1. Can be avoided. In addition, since the outrigger 45 is a protrusion that is close to the ground, the lawn mower 1 can travel so as to approach the grass collection container A or the like in a state where the outrigger 45 protrudes.

  In particular, in the embodiment, since the outrigger 45 is configured to protrude by the lifting hydraulic cylinder 30 in the lift mechanism 19, there is no need to separately provide a configuration for protruding the outrigger 45, and the configuration is simple. Thus, there is an advantage that a reduction in size and weight can be achieved.

  When the outrigger 45 protrudes so as to approach the ground 4, at the same time, the bumper body 46 provided on the lever body 40 protrudes backward to substantially the same position as the stopper portion 44. In this state, the stopper portion 44 protrudes further rearward. That is, before the lifting operation of the grass collection box 18, the outrigger 45 protrudes so as to approach the ground 4, and the bumper body 46 protrudes rearward.

  Next, when the pair of upper and lower lift links 31 and 32 are rotated upward by the further piston projecting motion in both the lifting and lowering hydraulic cylinders 30, as shown in FIG. When the bottom cover plate 20 and the rear cover plate 21 are lifted in a closed state and are lifted up to the highest maximum raised position, the lift control lever 54 is operated to the neutral position to thereby move the both lift hydraulic pressures. Further piston projecting movement in the cylinder 30, that is, lifting of the grass collection box 18 is stopped, and at the same time, the grass collection box 18 is locked by the locking means 49 so as not to descend from the highest position.

  It should be noted that both the lifting hydraulic cylinders 30 can be configured to be in a neutral position where the operation of the piston is automatically stopped when the grass collection box 18 is lifted to the maximum raised position. Further, when the grass collection box 18 is in a state of accepting the cut grass discharged from the discharge duct 14 in the lowered position, the grass collection box 18 is inclined forward so that the front portion is low and the rear portion is high, but is raised to the highest position. On the other hand, the rear part is inclined so that the front part is high and the rear part is low.

  In this state, the lawn mower 1 is operated so as to travel forward or backward so that the rear part approaches the grass collection container A placed on the ground 4 as shown in FIG. The grass collection box 18 lifted high as described above is positioned directly above the grass collection container A. When the lawn mower 1 travels backward so that the rear part of the lawn mower 1 approaches the grass collection container A, the bumper body 46 is damaged by the collision with the grass collection container A. Can be avoided reliably. In particular, since the bumper body 46 is configured to protrude outward from at least the base end portion of the lifting hydraulic cylinder 30 in the lift mechanism 19, the base end portion of the lifting hydraulic cylinder 30 is damaged. It can be surely prevented.

  In addition, the bumper body 46 protrudes at any time from the start of lifting of the grass collection box 18 to the middle of lifting, and does not protrude during normal travel. It can be surely avoided that it hinders driving. In the embodiment, since the protruding movement of the bumper body 46 is performed in the lifting hydraulic cylinder 30 of the lift mechanism 19 similarly to the outrigger 45, it is necessary to separately provide a configuration for protruding the bumper body 46. Therefore, the configuration is simplified and the size and weight can be reduced.

  After the lawn mower 1 is moved so that its rear part approaches the grass collection container A placed on the ground 4, the open / close hydraulic cylinder 26 is operated to the open position of the open / close operation lever 53. The piston is operated so as to protrude. Then, as shown in FIG. 12, since the rear cover plate 21 with respect to the grass collection box 18 is opened and rotated, discharge of the cut grass in the grass collection box 18 into the grass collection container A starts.

  Next, the bottom cover plate 20 with respect to the grass collection box 18 is linked to the opening rotation of the rear cover plate 21 via a metal wire 27 having flexibility, and as shown in FIG. Since the bottom end of the grass collection box 18 is opened by turning up so that the rear end is lowered, the discharge of the cut grass in the grass collection box 18 further proceeds into the grass collection container A.

  When the rear cover plate 21 is fully opened, the opening / closing operation lever 53 is operated to the neutral position to stop further piston projecting movement in the both open / close hydraulic cylinders 26, that is, the opening operation of the rear cover plate 21. To do. The both opening and closing hydraulic cylinders 26 can be configured to be in a neutral position where the piston automatically stops operating when the rear cover plate 21 is fully opened.

  Next, with the discharge of the cut grass in the grass collection box 18, the cut grass that has been discharged and dropped hits the rear end of the bottom cover plate 20, so that the bottom cover plate 20 is in contact with the bottom cover plate 20 as shown in FIG. Since the metal wire 27 that interlocks and connects the bottom lid plate 20 and the rear lid plate 21 is loosened, it is automatically further opened and rotated regardless of the opening and rotation of the rear lid plate 21. All of the cut grass in the grass box 18 can be discharged, and the discharge position of the cut grass can be set away from the lawn mower 1.

  In particular, in the embodiment, the opening operation of the bottom cover plate 20 is configured to rotate and open so that the front end of the bottom cover plate 20 jumps up into the grass collection box 18 and the rear end portion is lowered. The cut grass in the grass box 18 is discharged not only from the rear opening of the grass collection box 18 but also from the portion corresponding to the rear end of the bottom cover plate 20 among the open bottoms of the grass collection box 18. Therefore, there is an advantage that the cut grass can be discharged reliably and quickly.

  In the embodiment, the bottom lid plate 20 is formed by bending a thin metal plate into a sawtooth cross section, so that the bottom lid plate 20 can be significantly reduced in weight while ensuring the rigidity of the bottom lid plate 20. Since the grass box 18 can be further reduced in weight, the overall lawn mower 1 can be further reduced in size and weight. Moreover, since the sawtooth cross section of the bottom cover plate 20 is provided with an inclined portion 20a obliquely upward from the front end toward the rear, when the bottom cover plate 20 is flipped up, the mowing grass on the upper surface thereof is inclined. It will slide down along 20a. For this reason, it is possible to reliably avoid the mowing grass from adhering to the upper surface of the bottom cover plate 20. In particular, since the bottom cover plate 20 is made of a thin metal plate having air permeability, the weight of the bottom cover plate 20 can be further reduced, and the above-described effects can be promoted and the cost can be reduced.

  As is clear from the above embodiment, the discharge of the cut grass from the grass collection box 18 is performed by the bottom cover plate 20 that closes the open bottom of the grass collection box 18 and the back cover plate that closes the opening on the rear surface of the grass collection box 18. This is done by opening 21. For this reason, unlike the conventional case, it is not necessary to rotate the entire grass collecting box 18 in a state where the grass collecting box 18 is lifted high. Therefore, the height of the center of gravity from the ground when the grass collecting box 18 is lifted high is higher than the conventional case. Can be greatly reduced. In addition, the opening and closing operation of the bottom cover plate 20 and the rear cover plate 21 can be performed with a small mechanism (for example, a hydraulic cylinder) having a relatively small output than the conventional case, and the weight of the grass collection box 18 as a whole can be reduced. The support stability in the state where the grass collection box 18 is lifted high can be further improved, and the lift mechanism 19 can be reduced in size and weight, and thus the overall lawn mower 1 can be reduced in size and weight.

  In addition, in the embodiment, the bottom cover plate 20 and the rear cover plate 21 are interlocked and connected via a flexible member 27 (metal wire) disposed in the grass collection box 18. Since the interlocking mechanism can be built in the grass collection box 18, and the grass collection box 18 can be further reduced in size and weight, it can contribute to further downsizing and weight reduction of the entire lawn mower 1.

  In particular, both ends of the metal wire 27 are twisted at an appropriate angle around the axis thereof and coupled to the rear cover plate 21 and the bottom cover plate 20, thereby improving the durability of the flexible member and reducing the weight. Can be realized. Further, the middle part of the metal wire 27 is in contact with the upper surface of the bottom cover plate 20 when the bottom cover plate 20 is closed. It won't get in the way.

  In addition, the opening rotation by the cut grass being discharged and hitting the rear end of the bottom cover plate 20 is configured to follow the opening rotation of the rear cover plate 21 as described below. Yes. That is, as shown in FIG. 9, a lever body 56 having a receiving piece 56 a with which the lower surface of the rear end portion of the bottom cover plate 20 contacts the pivot pin 55 at the base end of the opening / closing hydraulic cylinder 26. The lever body 56 is provided so as to be rotatable. The lever body 56 is pivoted to the lower link 25 via the link 57 in accordance with the upward rotation of the lower link 25, that is, the rotation of the rear cover plate 21 in the opening direction. It connects so that it may rotate. For this reason, the opening rotation due to the cutting grass being discharged and falling hits the rear end of the bottom cover plate 20, and consequently the discharge of the cutting grass by the opening rotation in the bottom cover plate 20 is not performed at once. .

  In addition, in the embodiment, the bottom guide plate 28 opens and rotates together with the bottom cover plate 20 and enters the grass collection box 18, so that the mowing grass deposited on the bottom guide plate 28 is removed from the top surface of the bottom guide plate 28. Along with the cut grass on the bottom cover plate, it falls into the container A for grass collection. That is, according to the lawn mower of the embodiment, the mowed grass accumulated on the upper surface of the bottom guide plate 28 can be reliably discharged out of the grass collection box 18.

  Thus, when the discharge of the cut grass in the grass collection box 18 into the grass collection container A is completed, the rear cover plate 21 is closed by operating the open / close operation lever 53 to the closed position. In this case, since the center of the opening rotation in the bottom cover plate 20 is located at a position shifted to the rear end from the center position of the front end and the rear end of the bottom cover plate 20, the bottom cover plate 20 is It closes automatically by the weight at its front end. The opening / closing operation lever 53 is in a neutral position when the rear cover plate 21 is closed, but may be configured to perform this automatically.

  Next, after the lawn mower 1 is moved away from the grass collection container A, the lifting operation lever 54 is operated to the lowered position, and both the lifting hydraulic cylinders 30 are operated to move backward in the piston. As shown in FIG. 10, the grass collection box 18 descends and returns to a posture for receiving the mowing grass discharged from the discharge duct 14.

  Next, when both the lifting hydraulic cylinders 30 are further moved backward by the pistons, the two lever bodies 40 are rotated forward so that the pivot pins 43 are separated from the stopper portions 44, and the stopper pieces 47. , The outrigger 45 and the bumper body 46 are returned to their original retracted positions to perform the mowing operation as shown in FIG. Return to the state.

  The elevating operation lever 54 is in a neutral position when the two lever bodies 40 are rotated forward so as to contact the second bracket member 35 or the mast member 29, but this is automatically performed. You can also Moreover, although the said embodiment was a case where it comprised so that the protrusion in the said outrigger 45 might be performed in the time before starting the raising of the said grass collection box 18 (immediately before), in another embodiment, Can be configured to be performed after the start of lifting of the grass collection box 18 and until the grass box 18 is lifted to a high height, that is, in the middle of lifting.

(9). In addition, each structure of above-mentioned embodiment is not limited to the thing of illustration, A various change is possible in the range which does not deviate from the meaning of this invention.

It is a side view of the lawn mower in an embodiment. It is a top view of FIG. It is the perspective view which removed the grass collection box in FIG. 1, and was seen from diagonally back. It is the perspective view which looked at the grass collection discharge mechanism in FIG. 1 from diagonally forward. FIG. 5 is a sectional view taken along line IV-IV in FIG. 4. It is a perspective view which shows the lift mechanism which comprises a grass collection discharge | emission mechanism. It is a principal part enlarged view of FIG. It is the perspective view which looked at the grass collection box from diagonally forward in the maximum raising position. It is the perspective view which looked at the grass collection box from diagonally backward in the maximum raising position. It is a figure which shows the 1st state of a mowing grass discharge | release operation | work. It is a figure which shows the 2nd state of a mowing grass discharge | release operation | work. It is a figure which shows the 3rd state of a mowing grass discharge | release operation | work. It is a figure which shows the 4th state of a mowing grass discharge | release operation | work. It is a figure which shows the 5th state of a mowing grass discharge | release operation | work. It is a hydraulic circuit diagram of a lawn mower. It is a partially notched side view which shows the attachment structure of a raising / lowering operation lever and an opening / closing operation lever. It is a front view which shows the attachment structure of a raising / lowering operation lever and an opening / closing operation lever. It is action | operation explanatory drawing of an opening / closing operation lever. It is action | operation explanatory drawing of a raising / lowering operation lever. It is an electric circuit diagram of a limiting mechanism. It is an electric circuit diagram of a PTO regulation mechanism. It is a side view which shows the state of unloading work. It is a partially omitted front view of a traveling machine body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lawn mower 2 Traveling machine body 5 Front wheel 6 Rear wheel 7 Engine 9 Control seat 13 Rotary-type lawn mowing mechanism 14 Exhaust duct 16 Grass collection mechanism 18 Grass collection box 18a Front opening part (mowing grass reception)
19 Lift mechanism 20 Bottom lid plate 21 Rear lid plate 23 Pivoting pin 28 Bottom guide plate 28a Bottom plate 28b Guide side plate

Claims (2)

A lawn mowing mechanism mounted on a traveling machine body, a grass collection box communicating with a discharge duct extending from the lawn mowing mechanism, a lift mechanism for lifting the grass collection box, and for turning on and off the lawn mowing mechanism A lawn mower equipped with a PTO operating body,
The grass collection box has a bottom cover plate that closes and opens an opening formed on the bottom surface, and the bottom cover plate can be opened and operated with the grass collection box held at a lowered position for receiving the cut grass. Is composed of
Grass collection detection means for detecting the vertical position of the grass collection box, attitude detection means for detecting the opening / closing attitude of the bottom cover plate, and PTO detection for detecting the on / off operation state of the PTO operating body Means, and clutch means for interrupting power transmission from the engine mounted on the traveling machine body to the lawn mowing mechanism,
When the grass detection box detects that the grass collection box is in the lowered position, and the posture detection means detects that the bottom cover plate is in a predetermined opening / closing position, the PTO The clutch means is configured to be in a power connected state only when the detecting means detects an entry operation of the PTO operating body.
Lawn mower. The bottom cover plate is attached with a bottom guide plate that protrudes from the cut grass receiving port of the grass collection box toward the discharge duct in a state in which the bottom cover plate is closed. It is configured to open and rotate so that the bottom guide plate side jumps up toward the grass collection box,
The bottom cover plate that has been opened and rotated in a state where the grass collection box is in the lowered position is held in a tilting posture in which the tip of the bottom guide plate faces the upper portion of the cut grass discharge port in the discharge duct. Configured to
The opening and closing postures of the bottom cover plate detected by the posture detecting means are a closing posture and a tilting posture.
The lawn mower according to claim 1.

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