JP5200041B2 - Walking mower - Google Patents

Description

  The present invention is provided with a housing having a front wheel and a rear wheel, drives a cutting blade in the housing with a driving force from a driving part, and drives the driving force from the driving part by the traveling transmission mechanism to the front wheel and the rear wheel. The present invention relates to a walk-type mower transmitted to a rear wheel, and more particularly to improvement of a traveling drive system.

  Patent Document 1 discloses a walking-type grass mower configured as described above. In the walking-type grass mower, a transmission system that transmits the driving force of the engine to the traveling wheels at the front and rear positions is provided, and tension is applied to the chain. The structure to be operated is described.

  Specifically, in Patent Document 1, a chain is wound around a sprocket of a traveling output shaft to which a driving force of an engine is transmitted and a sprocket on a wheel side, and a tie toner that applies tension to the chain; A pair of tension rollers is provided, and a single spring is provided across the arms that support the pair of tension rollers. In this configuration, the slack of the chain can be suppressed by the action of tension by displacing the pair of tension rollers so as to press against the chain by the biasing force of the spring.

Japanese Patent Laying-Open No. 2005-138718 (paragraph number [0039], FIG. 10)

  The chain transmission system employs a structure that removes slack by displacing the tension roller, tension sprocket, etc. in the low tension area of the chain wound around the sprocket more than the other area (high tension area). Yes.

  As described in Patent Document 1, a walking type grass mower equipped with a transmission system that transmits driving force to the front and rear wheels via a chain can switch the traveling direction of the machine body between forward and reverse. The region of tension that acts strongly on the chain is switched. In particular, as described in Patent Document 1, in a case where a single endless chain is wound around a sprocket for a front wheel, a sprocket for a rear wheel, and a sprocket serving as a drive source, When the direction is switched, the rotational direction of the chain is switched, and the region where the tension acts on the chain inevitably changes.

  In addition, since the transmission system described in Patent Document 1 includes two tension rollers, when the traveling machine body is moving forward and backward, the two tension rollers in the region where the tension is lowered protrude. Displace in the direction. However, since Patent Document 1 has two arms each having a tension roller and supports each arm so as to be swingable around different axes, the structure is likely to be complicated and there is room for improvement.

  An object of the present invention is to rationally configure a walking type mower that removes slack in a chain that transmits power to wheels even when the traveling direction of the traveling machine body is switched.

A feature of the present invention is that a housing having a front wheel and a rear wheel is provided, a cutting blade in the housing is driven by a driving force from the driving portion, and the driving force from the driving portion is transmitted to the front by a traveling transmission mechanism. A walking mower that transmits to the wheels and rear wheels,
A forward / reverse switching mechanism that converts the driving force of the prime mover to forward driving force or reverse driving force and transmits it to a single output shaft;
The travel transmission mechanism includes an output sprocket provided on the output shaft, a front input sprocket that transmits power to the front wheels, a rear input sprocket that transmits power to the rear wheels, and an endless chain wound around them. As well as
Of the endless chain, a front tension member that applies tension to a region extending from the output sprocket to the front input sprocket, and a rear tension member that applies tension to a region extending from the output sprocket to the rear input sprocket. Prepared,
The front tension member is supported by a front tension arm swingable about the output shaft center of the output shaft, and the rear tension member is swingable about the output shaft core of the output shaft. An urging means is provided across the front tension arm and the rear tension arm so as to be supported by a tension arm and apply tension to the endless chain from the front tension member and the rear tension member. In the point.

According to this configuration, in the case where the traveling machine body is moved forward or backward, the region of the endless chain reaching the front input sprocket with respect to the output sprocket or the rear portion with respect to the output sprocket. The tension in one of the endless chain regions leading to the input sprocket increases and the tension in the other region decreases. Further, since the front tension arm and the rear tension arm are supported so as to be swingable around the output shaft core, and the biasing force of the biasing means acts between them, the front tension member, the rear tension member, Of these, the overhang of the one corresponding to the region where the tension is increased is suppressed, and at the same time, the overhang of the one corresponding to the region where the tension is decreased is allowed to remove the slack of the endless chain. In particular, since the front tension arm and the rear tension arm are supported so as to be swingable around the output shaft core, not only a plurality of support shafts are required, but also the output shaft is used as a support shaft for the tension arm. Can be combined.
Therefore, a walking mower that simply removes the slack of the chain that transmits power to the wheels even when the traveling direction of the traveling machine body is switched is simply configured.
Further, in the present invention, the output shaft is disposed outside a loop-shaped region around which the endless chain is wound, and the front tension member and the rear tension member are loop-shaped regions around which the endless chain is wound. You may arrange | position inside. With this configuration, the endless chain can be driven by the output sprocket inside the loop-shaped region, and tension can be applied to the endless chain by the tension member outside the loop-shaped region.

  In the present invention, the boss portion of the front tension arm and the boss portion of the rear tension arm may be loosely supported at a position sandwiching the output sprocket from the direction of the output shaft core.

  According to this, it becomes possible to arrange | position a front part tension arm and a rear part tension arm in the position close | similar to the endless chain wound around an output sprocket. In particular, in this configuration, it is possible to use members having the same shape for the front tension arm and the rear tension arm, thereby realizing the shared use of parts.

The present invention provides a main chain in which the output sprocket, the front input sprocket, the rear input sprocket, the endless chain wound around them, the front tension member, and the rear tension member are sealed. Housed in a case,
A chain type transmission mechanism that transmits the driving force from the front input sprocket to the front wheels is housed in a front chain case having a sealed structure, and the chain type transmission that transmits the driving force from the rear input sprocket to the rear wheels. The mechanism may be housed in the rear chain case of the sealing structure.

  According to this, it becomes possible to transmit the driving force of the prime mover to the front and rear wheels via the main chain case, the front chain case, and the rear chain case. Since each chain case has a sealed structure, lubrication oil is sealed and smooth transmission is continued.

It is a whole side view of a walk-type mower. It is a whole top view of a walking type mower. It is a side view which shows the inclination posture of the transmission case at the time of advance. It is a side view which shows the inclination posture of the transmission case at the time of reverse drive. It is a longitudinal cross-sectional view of a housing and a handle support part. It is a figure which shows a power transmission structure typically. It is a perspective view which shows the structure of a housing. It is sectional drawing of the cutting height adjustment mechanism in the state which introduce | transduced the control pin into the 3rd opening width of the control member, and advanced the body. It is sectional drawing of the cutting height adjustment mechanism in the state which introduce | transduced the control pin into the 3rd opening width of the control member, and made the body reverse. It is sectional drawing which shows the state which introduced the control pin into the 2nd opening width of a control member. It is sectional drawing which shows the state which introduced the control pin into the 1st opening width of a control member. It is a top view of a cutting height adjustment mechanism. It is a disassembled perspective view of a cutting height adjustment mechanism. It is a side view which shows the support structure of a wheel. It is sectional drawing which shows the support structure of a wheel. It is sectional drawing which shows the drive mechanism which has the main drive chain. It is a figure which shows cooperation with the switching lever and the forward / reverse switching lever. It is a figure which shows cooperation with the switching lever locked by the lock bolt, and the forward / reverse switching lever. It is a figure which shows the attitude | position of the tension arm at the time of advance of a body, a stop, and the reverse. It is a top view which shows a disk and a cutting blade. It is a perspective view which shows the structure of the housing provided with the guide wall.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration]
As shown in FIGS. 1 to 5, the front wheel 1 is provided at the front end position of the housing A constituting the traveling machine body, the rear wheel 2 is provided at the rear end position, and the handle support portion B at the side position of the housing A is provided. A transmission case 5 that supports the base end portion of the steering handle 3 and that has an engine 4 serving as a driving portion at an upper portion thereof is provided in a state of vertically passing through the housing A, and the lower end of the transmission case 5 from the drive shaft 6 is provided. The housing is provided with a cutting mechanism C having a plurality of cutting blades 7 that rotate around a vertical driving axis Y by a driving force, and travels that transmit the driving force from the transmission case 5 to the front wheels 1 and the rear wheels 2. A walking mower is configured with the transmission mechanism D.

  As shown in FIGS. 1 to 5 and 7, the housing A includes a top plate 20 </ b> A having an upper wall that curves so as to protrude smoothly upward, and a side wall 20 </ b> B having a vertical wall shape on both sides of the top plate 20 </ b> A. The frame 20 has a structure in which end plates 20C having a vertical wall shape are integrally formed at the front and rear end portions of the top plate 20A. An opening H is formed at the center position of the top plate 20A of the frame 20, and the position is such that the opening H is vertically inserted and swingable about the swing axis X in a horizontal orientation in the horizontal direction. A transmission case 5 is supported by the housing A. The handle support portion B of the steering handle 3 described above is formed so as to protrude outward from one side plate 20B of the housing A. In particular, the transmission case 5 swings the upper end of the drive shaft core Y equally in the front direction and the rear direction of the traveling machine body based on the neutral posture in which the drive shaft core Y is perpendicular to the ground. The swing region is set so that it can be done.

  The engine 4 as a driving part includes a recoil starter 4A and a fuel tank 4B. As shown in FIG. 6, the upper position of the transmission case 5 is provided with a main clutch MC, and the cutting clutch CC is provided in a transmission system for cutting that transmits the driving force from the main clutch MC to the driving shaft 6 at the lower end of the driving force. It is intervening. The traveling transmission system that transmits the driving force from the main clutch MC to the front wheels 1 and the rear wheels 2 includes a speed switching mechanism SM that switches the driving speed (the number of revolutions per unit time) between high and low. A forward / reverse switching mechanism FRM that converts the driving force from the speed switching mechanism SM into a forward driving force for forward movement or a reverse driving force for backward movement and transmits it to the output shaft 8 is provided.

  The reaping clutch CC shifts the clutch member 102 that is spline-fitted to the drive shaft 6 along the drive shaft Y to the drive rotating body 101 to which the drive force from the engine 4 is transmitted. It is configured in a dog clutch type that reveals.

  The speed switching mechanism SM has a speed reducing shaft 103 and a power take-off shaft 104, which are transmitted by the worm gear mechanism W being decelerated by the worm gear mechanism W. The speed switching mechanism SM is arranged in a parallel posture. The first gear 105, the second gear 106 that transmits power to the power take-out shaft 104 by meshing with the first gear 105, and the third gear 107 on the speed increasing side that is loosely supported on the reduction shaft 103, and meshes with the second gear 106. And a fourth gear 108 for transmitting power to the power take-off shaft 104, and a shift member 109 that is spline-fitted to the reduction shaft 103 and meshes with either the first gear 105 or the third gear 107 by a shift operation. I have.

  The forward / reverse switching mechanism FRM is spline fitted to the output shaft 8 and a bevel gear 110 that rotates integrally with the power take-off shaft 104, a pair of switching gears 111 that are loosely supported on the output shaft 8 so as to mesh with the bevel gear 110. And a switching member 112 that meshes with one of the pair of switching gears 111 by a shift operation.

  The above-described output shaft 8 is disposed on the same axis as the swing axis X and protrudes on the opposite side of the handle support B described above. As the travel transmission mechanism D, a main chain case 10 to which the driving force from the output shaft 8 is transmitted, a front chain case 11 to transmit the driving force from the front end side of the main chain case 10 to the front wheels 1, and a main chain case 10 and a rear chain case 12 for transmitting the driving force from the rear end portion to the rear wheel 2.

  The steering handle 3 is supported so that the base end of the steering handle 3 can rotate about the switching axis P in the vertical orientation with respect to the handle support B, and the posture can be changed about the horizontal axis Q in the horizontal orientation. In addition, a loop-shaped grip 3G is provided at the extended end. In addition, at the base end portion, a first lock mechanism L1 that holds a turning posture around the switching axis P and a second lock mechanism L2 that holds a swinging posture around the horizontal axis Q are provided. I have.

  Near the grip 3G at the extended end of the steering handle 3, the main clutch lever 13, the forward / reverse switching lever 14 for shifting the forward / reverse switching mechanism FRM, and the first locking mechanism L1 are released. The lock release lever 15 and the second lock release lever 16 that performs the release operation of the second lock mechanism L2 are provided. Note that a throttle operating tool for setting the rotational speed of the engine 4, a shift operating tool for operating the speed switching mechanism SM, and a clutch operating tool for operating the cutting clutch CC are not shown in the drawing.

  The main clutch lever 13 is supported so as to be able to swing around a laterally oriented axis and is spring-biased in the cutting direction. With such a configuration, when the operator performs an operation of gripping the main clutch lever 13 against the biasing force of the spring, the main clutch MC reaches the engaged state, and the cutting blade 7, the front wheel 1 and the rear wheel 2 are driven. Power is transmitted. Further, when the operator releases his / her hand from the main clutch lever 13, the main clutch MC reaches the cutting position by the biasing force of the spring, the transmission of power to the cutting blade 7 and traveling is cut off, and the operation stops.

  The forward / reverse switching lever 14 is configured to be switchable between a forward position F, a neutral position N, and a reverse position R by an operation around an axial center in a vertical posture, and a traveling direction can be switched by an operator's operation. To. The first lock release lever 15 and the second lock release lever 16 are spring-biased in a direction to maintain the locked state, and the lock can be released by the operator's grip operation to adjust the attitude of the steering handle 3.

[Outline of mowing work]
When performing the work of cutting grass with the walking mower from such a configuration, the steering handle 3 can be extended by setting the amount of rotation about the switching axis P and the amount of oscillation about the horizontal axis Q. The exit direction and the height of the extended end can be set to positions suitable for work. Then, the engine 4 is started, the traveling speed and the traveling direction are set, the main clutch MC and the reaping clutch CC are turned on and the traveling is started, so that the driving force from the engine 4 is applied to the front wheels 1 and the rear wheels. 2 and simultaneously to the cutting blade 7. As a result, the grass is cut by the cutting blade 7 of the cutting mechanism C as it travels. Further, at the time of such cutting, the transmission case 5 swings around the swing axis X as shown in FIG. 3 or 4 due to a reaction (described later) accompanying the rotation of the output shaft 8, and this inclination amount is reduced. The value regulated by the cutting height adjusting mechanism E is reached. That is, the relative distance between the locus of the tip of the cutting blade 7 and the ground is set by the cutting height adjusting mechanism E, and the cutting height can be adjusted. Details of the configuration of the walking type mower in order to realize the cutting in such a form will be described below.

〔Wheel〕
A front axle frame 21 having a round pipe shape is connected to a front end position of the left and right side plates 20B of the frame 20 constituting the housing A via a bracket 21A, and the front axle 1A connected to the front wheel 1 with respect to the front axle frame 21. Is rotatably supported by a bearing such as a ball bearing. Similarly, a round pipe-shaped rear axle frame 22 is connected to the rear end position of the left and right side plates 20B via a bracket 22A, and the rear axle 2A connected to the rear wheel 2 with respect to the rear axle frame 22 is a ball bearing. It is supported rotatably by a bearing such as.

  As shown in FIGS. 14 and 15, both the front wheel 1 and the rear wheel 2 are welded with a wheel-like foil body 24 by welding or the like to a cylindrical boss shaft 23 fitted on the front axle 1A or the rear axle 2A. A plurality of metal lug plates 25 are provided on the outer peripheral portion of the foil body 24 by spot welding or the like, and a fixing pin 26 is inserted between the boss shaft 23 and the axle (the front axle 1A or the rear axle 2A). By doing so, the axle (the front axle 1A or the rear axle 2A) and the wheel (the front wheel 1 or the rear wheel 2) are integrally rotated. In addition, the foil body 24 formed a space between the pair of disk-shaped members by connecting the flange portions on the outer periphery of the pair of disk-shaped members formed into a foil shape by pressing a metal plate by spot welding or the like. It has a structure.

  In particular, the outer end portion of the front axle 1A and the rear axle 2A where the boss shaft 23 is fitted is reduced in diameter to form a grease space G and filled with grease, and at a position sandwiching the grease space G. An O-ring 27 is provided. Even in a situation where rust is generated outside due to long-term use from such a structure, the pair of O-rings 27 and the part of the grease space G at a position sandwiched between the O-ring 27 and the front axle 1A and the rear axle 2A Intrusion of rust into the boss shaft 23 is prevented, and fixing due to rust is prevented, so that the front axle 1A or the rear axle 2A can be removed integrally with the boss shaft 23.

  Further, the housing A may be provided with a fender 28 that covers the upper part of the outer periphery of the front wheel 1 or the rear wheel 2. Thus, by providing the fender 28, generation | occurrence | production of the dust from the site | part of the front wheel 1 or the rear wheel 2 can be suppressed, and the winding of the grass around the front wheel 1 or the rear wheel 2 can be suppressed.

〔housing〕
As shown in FIGS. 3, 5, and 7, the housing A is a circular pipe connected to each side plate 20 </ b> B while penetrating the side plates 20 </ b> B on both sides below the opening H at the center position inside the frame 20. A pair of horizontal frames 30 are provided in a horizontal posture and in a parallel posture. A first bracket 31 having a shape protruding upward is connected to a portion exposed to the opening H on the side close to the handle support portion B of the pair of horizontal frames 30, and the main chain on the top surface of the top plate 20 </ b> A of the frame 20. A second bracket 32 having a shape protruding upward is connected to the side close to the case 10. Further, the axis of the cylindrical bearing 31A of the first bracket 31 and the axis of the ball bearing 32A supported by the second bracket 32 are aligned with the swing axis X.

  Then, the shaft 33 provided in the transmission case 5 is rotatably inserted into the cylindrical bearing 31A of the first bracket 31, and the output shaft 8 of the transmission case 5 is rotated with respect to the ball bearing 32A of the second bracket 32. Supports freely. Accordingly, the transmission case 5 is supported with respect to the housing A so as to be swingable about the swing axis X.

  The housing A is formed by pressing a steel plate to form a top plate 20A, a side plate 20B formed by bending the left and right ends of the top plate 20A downward, and bending the front and rear ends of the top plate 20A downward. The frame 20 has a structure in which the end plate 20C is integrally formed. For this reason, the frame itself has high strength. A pair of horizontal frames 30 penetrating the central portion of the frame 20 in the lateral direction are connected, and a front axle frame 21 and a rear axle frame 22 are fixedly provided at both front and rear ends of the frame 20. The strength of A is further increased, and a structure that does not cause deformation or distortion even when an external force is exerted appears.

  In particular, as will be described below, the ends of the pair of horizontal frames 30 protrude outward from the side plate 20B, and a handle support portion B is formed at the protruding portion, so that the frames are specially attached to the housing A. Although it is a structure that is not added, a strong handle support B is created. In this walking type mower, the housing may be made of a resin such as FRP, and may be provided with three or more horizontal frames 30. As the horizontal frame 30, in addition to the round pipe material, for example, a square pipe material, Angle material may be used.

[Housing: Handle support part]
An end of the lateral frame 30 opposite to the traveling transmission mechanism D (opposite to the output shaft 8) is protruded from the side plate 20B, and a handle support B is formed at the protruding portion. The handle support part B includes a cylindrical body 35 in a vertically oriented posture that is arranged coaxially with the switching shaft core P, a horizontal support plate 36 provided at the upper end of the cylindrical body 35, and a cylindrical body. A rotating shaft 37 inserted in a rotatable manner relative to the upper surface 35, a rotating plate 38 connected and fixed to the rotating shaft 37 so as to be movable in sliding contact with the upper surface of the support plate 36, and a lateral end at the upper end of the rotating shaft 37. A swing frame 39 that is swingably supported about the axis Q and connected to the steering handle 3 and a lock frame 40 that has an arc surface centered on the horizontal axis Q and is supported by the rotating plate 38 are provided. ing.

  The first locking mechanism L1 described above is engaged with a large number of engagement holes 36A drilled on an arcuate region centered on the switching axis P with respect to the support plate 36, and these engagement holes 36A. The first lock pin 41 that is spring-biased in the direction to be supported and supported by the rotary plate 38 and the first lock pin 41 that is operated in the direction of pulling out from the engagement hole 36A by the operation force of the first lock release lever 15 described above. 1 operation wire W1. With this configuration, when the operator grips the first lock release lever 15, it is possible to arbitrarily set the rotation posture of the steering handle 3 around the switching shaft core P, and to release the grip operation. Thus, the first lock pin 41 is engaged with the engagement hole 36A, and the attitude of the steering handle 3 around the switching shaft P is maintained.

  The second lock mechanism L2 described above has a large number of engagement holes 40A formed in the lock frame 40, and a second spring mechanism biased in a direction to engage with the engagement holes 40A and supported by the swing frame 39. The second lock pin 42 and the second operation wire W2 that acts in the direction in which the second lock pin 42 is pulled out from the engagement hole 40A by the operation force of the second lock release lever 16 described above are provided. With this configuration, when the operator grasps the second lock release lever 16, the swinging posture of the steering handle 3 around the horizontal axis Q can be arbitrarily set, and the grasping operation is released. Thus, the second lock pin 42 engages with the engagement hole 40A, and the attitude of the steering handle 3 around the horizontal axis Q is maintained.

  In particular, a travel transmission mechanism D including a main chain case 10, a front chain case 11, and a rear chain case 12 is disposed on one side (right side) of the housing A, and the steering handle 3 is disposed on the other side (left side) of the housing A. Since it is arranged, the heavy objects are arranged symmetrically on the left and right, and the weight balance in the left and right direction of the traveling machine body is improved.

[Housing: Lower structure, etc.]
A pair of left and right auxiliary frames 43 are provided at the lower position of the housing A and directly below the transmission case 5 with respect to the lower surfaces of the pair of horizontal frames 30, and the lower surfaces of the pair of auxiliary frames 43 have hook-like shapes that open downward. The winding prevention body 44 is provided, and the lower end portion of the transmission case 5 is inserted into the central opening 44 </ b> A at the center position of the winding prevention body 44. Further, the dust cover 45 is provided on the left and right side plates 20B at a position outside the tip rotation locus of the cutting blade 7, and protective rods 46 are provided at the front and rear ends of the housing A.

  In this walking type mower, since the steering handle 3 is disposed on one side portion of the housing A, an operator is often located near the side portion. Even if the distance between the lower end position of the one on the side (left side) on which the steering handle 3 is disposed and the ground is shorter than that on the other side (right side), it is possible to suppress the scattering of dust to the operator. good.

[Running transmission mechanism]
As described above, the travel transmission mechanism D is composed of a chain-type transmission mechanism (a main drive chain 59 described later and a transmission chain 63) built in the main chain case 10, the front chain case 11, and the rear chain case 12. Is). As shown in FIGS. 6, 16, and 19, the main chain case 10 includes an output sprocket 50 that rotates integrally with the output shaft 8 and a front input sprocket that rotates integrally with the front input shaft 51 on the front end side. 52 and a rear input sprocket 54 that rotates integrally with the rear input shaft 53 of the rear end side, and a main drive chain 59 as an endless chain is wound around them.

  In this traveling transmission mechanism D, the main chain case 10 forms a sealed space in which the main drive chain 59 is accommodated by connecting aluminum alloy moldings with bolts or the like, and oil, grease, or the like is formed in this sealed space. Lubricating oil is enclosed. Further, the front chain case 11 and the rear chain case 12 form a sealed space in which the transmission chain 63 is accommodated by welding and fixing the outer periphery of a press-formed product of a metal plate. Oil or grease is contained in the sealed space. Is enclosed. Further, the front chain case 11 and the rear chain case 12 have a common structure, thereby reducing the number of parts.

  A front tension arm 55 on which the boss portion 55A is idle-supported on the output shaft 8 and a rear tension arm 57 on which the boss portion 57A is idle-supported on the output shaft 8 urge the output sprocket 50 to the swing axis X ( The output sprocket 50 is disposed in a direction along the direction along the output shaft core of the output shaft 8. A front tension sprocket 56 as a front tension member that applies tension to the main drive chain 59 in a region extending between the output sprocket 50 and the front input sprocket 52 is loosely supported on the extension end of the front tension arm 55. Yes. Further, a rear tension sprocket 58 as a rear tension member that applies tension to the main drive chain 59 in a region extending between the output sprocket 50 and the rear input sprocket 54 is idled and supported on the extending end of the rear tension arm 57.

  A spring 60 is provided as a biasing means for applying a biasing force in a direction in which the extending ends of the front tension arm 55 and the rear tension arm 57 are pulled toward each other. By providing the spring 60, the front tension sprocket 56 and the rear tension sprocket 58 are urged in the direction in which they approach each other by swinging about the swing axis X. The front tension arm 55 and the rear tension arm 57 have the same shape, and can be used in common, thereby reducing the cost. In this travel transmission mechanism D, a tension roller may be used instead of the front tension sprocket 56 and the rear tension sprocket 58.

  The aforementioned front input shaft 51 penetrates through one end of the front chain case 11, and the front axle 1A penetrates through the other end. The front chain case 11 includes a first sprocket 61 that rotates integrally with the front input shaft 51, a second sprocket 62 that rotates integrally with the front axle 1A, and a transmission chain 63 wound around these. ing. The rear input shaft 53 passes through one end of the rear chain case 12, and the rear axle 2A passes through the other end, and the rear chain case 12 has a first part that rotates integrally with the rear input shaft 53. 1 sprocket 61, a second sprocket 62 that rotates integrally with the rear axle 2A, and a transmission chain 63 wound around these. Further, the front axle 1A and the rear axle 2A are reduced in weight by cutting part of the central portion in the length direction.

  From such a configuration, the driving force from the output shaft 8 is transmitted to the transmission system of the main chain case 10 when the traveling machine body moves forward and backward, and further, is transmitted from the front chain case 11 to the front wheel 1. It is transmitted from the rear chain case 12 to the rear wheel 2. Furthermore, in the main chain case 10, as shown in FIG. 19, when the positional relationship among the main drive chain 59, the front input sprocket 52, and the rear input sprocket 54 is set, As shown in FIG. 5B, the front tension sprocket 56 and the rear tension sprocket 58 swing by an equal amount to apply tension to the main drive chain 59.

  When the traveling machine body travels forward, the tension sprocket in the region where the tension increases between the front tension sprocket 56 and the rear tension sprocket 58 with respect to the output sprocket 50 (the rear tension sprocket 58 in FIG. 5A). ) Moves to a position where it comes into contact with the linear path of the main drive chain 59, and at the same time, the tension sprocket (the front tension sprocket 56 in the figure) where the tension is lowered moves to a position where the main drive chain 59 is loosened. .

  On the contrary, when the vehicle travels backward, the tension in the reverse direction of the main drive chain 59 with respect to the output sprocket 50 is increased, so that the front tension sprocket 56 and the rear tension as shown in FIG. The posture of the sprocket 58 changes and the main drive chain 59 is loosened. As a result, even if the traveling machine body frequently advances and reverses, the front tension sprocket 56 and the rear tension sprocket 58 do not come off from the main drive chain 59, and the area where the tension of the main drive chain 59 decreases is slack. It is possible to eliminate the above-mentioned, and a good transmission can be realized without reducing the length of the main drive chain 59 wound around the output sprocket 50. When the traveling of the traveling machine body is stopped, the swinging amounts of the front tension sprocket 56 and the rear tension sprocket 58 are equal as shown in FIG.

[Mowing mechanism]
The cutting mechanism C is connected in a posture orthogonal to the drive shaft core Y with respect to the lower end of the flange portion 6A at the lower end of the drive shaft 6 protruding from the lower end of the transmission case 5 as shown in FIGS. The disc 65, the cutting blade 7 pivotably connected to the outer peripheral position of the disc 65 via a pin 66 in the vertical orientation, the plurality of wind-up plates 67 provided on the upper surface of the disc 65, and The anti-winding body 44 is provided.

  The disk 65 has a structure in which the whole is a disc shape, a connection portion is formed with the center portion bulging upward, and the periphery is bent slightly upward. The flange portion 6A of the drive shaft 6 is bolted to the connecting portion, and the four pins 66 penetrate vertically at equal intervals in the circumferential direction with respect to the outer peripheral position of the disk 65 (an angle of 90 degrees about the drive shaft core Y). And is supported.

  The cutting blade 7 is formed of a strip-shaped metal plate, and supports the base ends of a pair of cutting blades 7 facing each other with the coupling portion interposed therebetween so as to be swingable on the lower surface side of the disk 65, and is opposed to each other with the coupling portion interposed therebetween. The base end of the other pair of cutting blades 7 is supported swingably on the upper end side of the pin 66. Further, the lower cutting blade 7 is slightly bent with the tip side facing downward, and the upper cutting blade 7 is slightly bent with the tip side facing upward. As a result, the four cutting blades 7 are alternately arranged in the circumferential direction of the disk 65 at a low level on the lower surface side of the disk 65 and a high level on the upper end side of the pin 66.

  By forming the recess 67A in which the upper edge of the wind generating plate 67 is notched, a space is secured in which the lower edge of the wrapping preventing body 44 described above enters the recess 67A. The baffle 67 sucks outside air (air) above the housing A through an opening H formed in the housing A, and sends the sucked air in the circumferential direction along the upper surface of the disk 65. , And has a function of creating an air flow sent out of the housing A from the lower end of the housing A. The air flow created in this way contacts the outer surface of the engine 4 or the outer surface of the transmission case 5, thereby cooling the engine 4 and the transmission case 5 and suppressing the temperature rise of the oil inside the transmission case 5.

  In particular, in order to effectively perform cooling, as shown in FIG. 21, the outside air sucked into the opening H of the top plate 20A flows upward to the region as close to the transmission case 5 as possible. You may provide the guide wall 29 of the attitude | position which stands | starts up toward. In the same figure, what is provided on the front side and the rear side of the opening H is shown, but even if this guide wall 29 is provided on both sides, it is more efficient if it is provided over the entire circumference of the outer periphery of the opening H. Cooling can be performed.

[Cutting height adjustment mechanism]
As shown in FIG. 2, the cutting height adjusting mechanism E is arranged at the center position in the lateral width direction of the housing A on the upper surface of the housing A, and the cutting height adjusting mechanism E is centered in the lateral width direction of the transmission case 5. A regulating force is applied to the position. As a specific configuration, as shown in FIGS. 8 to 13, the cutting height adjusting mechanism E includes a support 71 fixed to a central position in the lateral width direction of the housing A on the upper surface of the housing A, a shaft 72, and the like. In addition to a regulation member 73, an adjustment lever 74 as an artificial operation tool, a coil spring 75, and a regulation pin 76 as a contact member, a link body 77 is provided.

  The support body 71 has a pair of side wall portions 71A and a lever guide wall 71B. The pair of side wall portions 71A has a through hole 71C through which the shaft 72 is inserted and a long hole-shaped guide hole 71D through which the regulation pin 76 is inserted. A slit-shaped lever guide 71E is formed on the lever guide wall 71B.

  The restricting member 73 has a pair of side wall plates 73A that are in sliding contact with the inner surfaces of the pair of side wall portions 71A of the support 71, and end wall plates 73B that are connected to the pair of side wall plates 73A. An opening 73C and a through hole 73D through which the shaft 72 is inserted are formed, and a lever hole 73E is formed in the end wall plate 73B. As shown in FIGS. 8 to 11, the restriction opening 73 </ b> C has three types of opening widths of a first opening width e <b> 1 that is the narrowest as a plurality of region widths, an intermediate second opening width e <b> 2, and a widest third opening width e <b> 3. In the narrowest first opening width e1, the restricting pin 76 as a contact member is fitted in close contact, and in the largest third opening width e3, the restricting pin 76 can be displaced the most, and the intermediate second In the opening width e2, the restriction pin 76 can be displaced smaller than the largest third opening width e3.

  A hole portion through which the regulation pin 76 is inserted is formed at one end portion of the link body 77, and a hole portion through which a connection pin 79 connected to the bracket 78 provided in the transmission case 5 is formed at the other end portion. ing. The link body 77 is connected to the center position in the lateral width direction of the transmission case 5 via the bracket 78.

  The cutting height adjusting mechanism E has a regulating member 73 fitted in the support 71, an adjusting lever 74 is disposed so as to be inserted into the lever hole 73E and the lever guide 71E, and the through holes 71C and 73D and the adjusting lever 74 are arranged. The shaft 72 is inserted through the proximal end of the coil spring 75 and the coil spring 75. Further, a regulation pin 76 is inserted through the guide hole 71 </ b> D of the support 71, the regulation opening 73 </ b> C of the regulation member 73, and one hole of the link body 77. Further, a connecting pin 79 is inserted through the other hole of the link body 77 and the bracket 78 of the transmission case 5. The coil spring 75 applies a biasing force in a direction in which the adjustment lever 74 is engaged with one of the three engagement recesses of the lever guide 71E.

  With this configuration, when the restriction pin 76 is introduced into the narrowest first opening width e1 of the restriction opening 73C by operating the adjustment lever 74, the adjustment lever 74 engages with the recess at the upper end of the lever guide 71E. As shown in FIG. 11, the drive shaft core Y is maintained in a neutral posture perpendicular to the ground. Even when the traveling machine body travels, the transmission case 5 does not swing around the swing axis X and the posture of the cutting mechanism C does not change, so that the cutting height is maintained at the highest value.

  Further, when the regulation pin 76 is introduced into the third opening width e3 having the widest opening width among the regulation openings 73C by the operation of the adjustment lever 74, the adjustment lever 74 is engaged with the recess at the lower end of the lever guide 71E, As shown in FIGS. 3, 8, and 9, since the restriction pin 76 can be displaced in the third opening width e <b> 3, the transmission case 5 is allowed to swing maximum about the swing axis X.

  Further, when the regulating pin 76 is introduced into the middle second opening width e2 of the regulating opening 73C by the operation of the adjusting lever 74, the adjusting lever 74 engages with the middle recess of the lever guide 71E, and FIG. As shown in the figure, since the restriction pin 76 can be displaced within the second opening width e2, the transmission case 5 is allowed to swing less than the maximum swing described above about the swing axis X.

  In the cutting height adjusting mechanism E, the reaction force when the rotational force of the output shaft 8 acts between the frame 20 and the transmission case 5 via the ball bearing 32A of the second bracket 32 during traveling of the traveling machine body. Swings the transmission case 5 and tilts the drive shaft Y by this swing to set the cutting height. Specifically, for example, when the traveling machine body is advanced in a situation where the regulation pin 76 is introduced into the third opening width e3, the output shaft 8 rotates as indicated by an arrow as shown in FIG. The reaction accompanying the rotation acts on the transmission case 5 from the ball bearing 32A in the direction of the arrow. When the reaction force acts in this way, the engine 4, the transmission case 5, and the cutting mechanism C swing integrally in the direction of the arrow about the swing axis X, and the cutting mechanism C Swings forward and downward.

  On the contrary, when the traveling machine body is moved backward, as shown in FIGS. 4 and 9, the output shaft 8 rotates in the direction of the arrow, and the reaction caused by this rotation is transferred from the ball bearing 32A to the transmission case 5. On the other hand, it acts in the direction of the arrow. When the reaction force acts in this way, the engine 4, the transmission case 5, and the cutting mechanism C swing integrally in the direction of the arrow about the swing axis X, and the cutting mechanism C Swings backward and downward.

  As described above, the cutting height adjusting mechanism E causes the traveling machine body to travel in a state in which the regulating pin 76 is introduced into the second opening width e2 or the third opening width e3 of the restriction opening 73C by the operation of the adjustment lever 74. By transmitting the reaction caused by the rotational driving force transmitted from the output shaft 8 to the front wheel 1 and the rear wheel 2 to the transmission case 5, the operator can perform the operation without swinging the transmission case 5 with the engine 4. As a result of the transmission case 5 and the cutting mechanism C swinging integrally around the swing axis X, the cutting operation at the cutting height set by the adjustment lever 74 can be performed.

[Another Embodiment of Cutting Height Adjustment Mechanism]
The cutting height adjusting mechanism E supports the support 71, the regulating member 73, and the regulating pin 76 as a contact member inserted into the regulating opening 73 </ b> C of the regulating member 73 on the transmission case 5. The other end of the link body 77 to which one end is connected may be supported by the housing A. When configured in this way, the transmission case 5 may be provided with an adjustment lever 74 as an artificial operation tool for operating the restriction member 73 so as to introduce the restriction pin 76 into the restriction opening 73C.

  Further, a groove having a region width may be formed in the restricting member 73 instead of the restricting opening 73C. Further, instead of changing the region width in a stepwise manner, for example, by setting the facing inner surfaces of the restriction openings 73C to be inclined (non-parallel), the region width is stepless (continuous). You may comprise so that it may change to.

[Forward / backward operation system]
As shown in FIG. 17, the forward / reverse switching lever 14 is supported so as to be freely set at the operation position of the forward position F, the neutral position N, and the reverse position R by swinging about the lever shaft 14A in the vertical orientation. A pair of arms 14B are formed at the base end. The transmission case 5 is provided with a switching lever 82 for rotating the switching shaft 81 for switching the switching member 112 of the forward / reverse switching mechanism FRM, and the pair of arms 14B and the position where the swinging ends of the switching lever 82 face each other. Two shift operation wires 83 are provided.

  As a specific structure, an outer portion 83A at the end of the transmission case on the transmission operation wire 83 is fixed to the holder 84 of the transmission case 5 by a nut 83N, and the inner portion 83B has a connecting pin 85. Via a switching lever 82. The outer portion 83A on the grip side of the steering handle 3 of the speed change operation wire 83 is fixed to the support frame 86 of the steering handle 3 by tightening a pair of nuts 83N, and the inner portion 83B is interposed via a coil spring 83S. It is connected to the arm 14B.

  In this forward / reverse operation system, the forward / reverse switching lever 14 is provided with an adjustment mechanism for properly presenting a shift state corresponding to each of the forward position F, the neutral position N, and the reverse position R. This adjusting mechanism includes a lock bolt 88 provided on the support piece 87 of the transmission case 5 and an engaging recess 82 </ b> A formed at the swing end of the switching lever 82. The engaging recess 82A is set in a positional relationship so as to face the lock bolt 88 in a posture in which the forward / reverse switching mechanism FRM is in the neutral position.

  When adjusting with this adjusting mechanism, as shown in FIG. 18, the switching lever 82 is set to the neutral position, and the tip of the lock bolt 88 is engaged with the engaging recess 82A by operating the lock bolt 88. Keep it. In this state, the nut 83N on the grip side of the steering handle 3 is operated to adjust the forward / reverse switching lever 14 to the neutral position N. Specifically, by moving the end portion of the outer portion 82A, the tension acting on the inner portion 83B changes, and the position of the forward / reverse switching lever 14 also changes corresponding to the tension. By such adjustment, the nut 83N is operated so that the forward / reverse switching lever 14 is in the neutral position N. After this adjustment, by properly disengaging the lock bolt 88, the forward / reverse switching lever 14 can be operated to switch back and forth appropriately.

  By providing this adjustment mechanism, it is possible to adjust the nut 83N while confirming the position of the forward / reverse switching lever 14 from the part of the grip 3G of the steering handle 3, and the switching lever 82 of the forward / reverse switching mechanism FRM can be adjusted. The forward / reverse switching lever 14 can be properly linked. When adjustment is performed, the nut 83N at the end of the transmission operation wire 83 on the transmission case side may be operated.

  INDUSTRIAL APPLICABILITY The present invention can be used for all walk-type grass mowers that transmit the driving force from the driving section to the front wheels and the rear wheels via a chain transmission mechanism.

1 Front wheel 2 Rear wheel 3 Steering handle 4 Driving part (engine)
7 Cutting blade 8 Output shaft 10 Main chain case 11 Front chain case 12 Rear chain case 50 Output sprocket 52 Front input sprocket 54 Rear input sprocket 55 Front tension arm 55A Boss portion 56 Front tension member (front tension sprocket)
57 Rear tension arm 57A Boss part 58 Rear tension member (rear tension sprocket)
59 Endless chain (Main drive chain)
60 Biasing means (spring)
63 Transmission mechanism A Housing D Traveling transmission mechanism FRM Forward / reverse switching mechanism X Output shaft core (oscillating shaft core)

Claims (4)

A housing having a front wheel and a rear wheel is provided, the cutting blade in the housing is driven by the driving force from the driving part, and the driving force from the driving part is transmitted to the front wheel and the rear wheel by a traveling transmission mechanism. A walking mower,
A forward / reverse switching mechanism that converts the driving force of the prime mover to forward driving force or reverse driving force and transmits it to a single output shaft;
The travel transmission mechanism includes an output sprocket provided on the output shaft, a front input sprocket that transmits power to the front wheels, a rear input sprocket that transmits power to the rear wheels, and an endless chain wound around them. As well as
Of the endless chain, a front tension member that applies tension to a region extending from the output sprocket to the front input sprocket, and a rear tension member that applies tension to a region extending from the output sprocket to the rear input sprocket. Prepared,
The front tension member is supported by a front tension arm swingable about the output shaft center of the output shaft, and the rear tension member is swingable about the output shaft core of the output shaft. An urging means is provided across the front tension arm and the rear tension arm so as to be supported by a tension arm and apply tension to the endless chain from the front tension member and the rear tension member. Walking type mower. The output shaft is arranged outside a loop-like region around which the endless chain is wound, and the front tension member and the rear tension member are arranged inside a loop-like region around which the endless chain is wound. The walking mower according to claim 1. The walking type grass mowing according to claim 1 or 2 , wherein the boss portion of the front tension arm and the boss portion of the rear tension arm are loosely supported at a position sandwiching the output sprocket from the direction of the output shaft core. Machine. The output sprocket, the front input sprocket, the rear input sprocket, the endless chain wound around them, the front tension member, and the rear tension member are accommodated in a main chain case having a sealed structure. ,
A chain type transmission mechanism that transmits the driving force from the front input sprocket to the front wheels is housed in a front chain case having a sealed structure, and the chain type transmission that transmits the driving force from the rear input sprocket to the rear wheels. The walking mower according to any one of claims 1 to 3, wherein the mechanism is accommodated in a rear chain case of a sealing structure.

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