JP6000151B2 - Working device connection structure for passenger work vehicles - Google Patents

Description

  The present invention relates to a mid-mount type working device disposed between a pair of left and right front wheels and a pair of left and right rear wheels, and a vertical swing provided with a pair of left and right front links and a pair of left and right rear links on a body frame. The power from the power take-off shaft arranged at the rear of the vehicle body is connected via a link mechanism of the type, and the power is supplied from the first universal joint, the relay transmission shaft configured to be stretchable, and the second universal joint. The present invention relates to a work device connection structure for a passenger work vehicle configured to transmit to a rearward input shaft provided in the work device.

  As a work device connection structure for a passenger work vehicle as described above, a mid-mount mower (mid-mount work device) is formed by the left and right front wheels stepping over the front wheel guide plate as the tractor (passenger work vehicle) moves forward. When reaching the abdomen of the tractor, the connecting pins provided at the free ends of the pair of left and right rear links are guided by the openings of the hooks in the pair of left and right support stays provided at the mid-mount mower and reach the innermost part. There is a configuration in which a clutch driving body provided at the rear end of the rear link is fitted to a clutch follower (input shaft) of a mid-mount mower so as to be capable of transmission (see, for example, Patent Document 1).

Japanese Utility Model Publication No.4-110428

  In the above configuration, when connecting the connecting pin of each rear link to the corresponding support stay of the mid-mount mower, the height position of each connecting pin is suitable for connection with the corresponding support stay (Patent Document) 1, after lowering each rear link to its lower limit position so as to be lower than the height position of the opening in each support stay, the left and right front wheels pass over the mower through the upper part of the front wheel guide plate. Go over the tractor and drive forward. Then, the left and right rear links or connecting pins slide in contact with the left and right support stays, etc. as the vehicle travels forward and forward, so that the left and right rear links and connecting pins resist the weight of the left and right support stays, etc. Displacement rises along. When the connecting pin reaches a height position suitable for connection with the corresponding support stay due to this upward displacement, each connection pin is engaged to the innermost part of the opening of the corresponding support stay and is supported. Engage with. In conjunction with this, the clutch driving body provided at the rear ends of the left and right rear links automatically reaches a height position suitable for fitting with the clutch driven body of the mid-mount mower and becomes the clutch driven body. Fits so that transmission is possible.

  By the way, in the technique described in Patent Document 1, a clutch support case that rotatably supports the clutch drive body is provided, and the pair of support pins protruding left and right from the clutch support case have the same height as the left and right connection pins. The clutch drive body is inserted into the connecting pipe fixed in the left-right direction at the rear end of the rear link so as to be positioned, so that the clutch drive body is allowed to change its posture with the pair of support pins as fulcrums. The rear link is provided at the rear end of the rear link.

That is, in the technique described in Patent Document 1, since the clutch support case is configured to freely change the posture with a pair of support pins as fulcrums, the mid-mount moor is connected by traveling forward. In addition, the posture of the clutch drive body is deviated from the posture suitable for fitting with the clutch follower, and the problem that the clutch drive body does not fit into the clutch follower is easily caused.

It is an object of the present invention to reliably connect a transmission system to a mid-mount working device by overcoming and traveling forward .

The problem solving means of the present invention is:
An up-and-down swing type link mechanism in which a mid-mount working device arranged between a pair of left and right front wheels and a pair of left and right rear wheels is provided on a body frame with a pair of left and right front links and a pair of left and right rear links. It can be moved up and down via
The power from the power take-out shaft provided at the rear of the vehicle body is transmitted to the rearward input shaft provided in the working device via the first universal joint, the relay transmission shaft configured to be extendable and the second universal joint. Configured as
The left and right rear links are pivotally connected to the body frame,
The engagement device includes an engagement portion provided at the free end portion of the pair of left and right rear links as the pair of left and right front wheels travels over the work device from behind the work device and travels forward. An engagement connecting mechanism for engaging and connecting to the joint portion;
A holder that rotatably supports the output shaft of the second universal joint that can be intermittently fitted to the input shaft is swung up and down via the left and right support shafts on the free ends of the left and right rear links. Equipped so that the output shaft swings up and swings with the release of the input shaft,
One of the output shaft and the input shaft is constituted by a cylindrical shaft provided with a diameter-expanded guide portion having a pre-expanded shape that guides the other of them into the interior,
During forward traveling after the pair of left and right front wheels have passed over the working device , the other fitting start end is located in a guide region of the enlarged diameter guide portion provided on one of the output shaft and the input shaft. A working device connection structure for a passenger work vehicle, comprising a swing restriction mechanism that prevents the output shaft from swinging upward from a predetermined forward lift posture so that a state can be obtained.

According to this means, for example, the vehicle moves forward in a state where the left and right rear links are lowered to the lower limit position so that the height position of the engaging portion is lower than the height position suitable for connection with the fitted portion. When performing driving by the action of the engagement connection Organization, the link and the engagement portions of the left and right rear rises displaced against their own weight, engaging portions by the increased displacement in connection with the engaged portions If it raises to a suitable height position, an engaging part will engage with an to-be-engaged part with subsequent forward travel.

Further, when the pair of left and right front wheels get over the work device by overcoming forward traveling, the swing restricting mechanism causes the enlarged diameter guide portion provided on one of the output shaft of the second universal joint and the input shaft of the work device. Since the other fitting start end portion is maintained in the guide region, the output shaft of the second universal joint and the working device of the working device are moved along with the forward travel after the pair of left and right front wheels get over the working device. By the action of the enlarged diameter guide portion provided on one of the input shafts, the other of them can be reliably fitted and guided toward the inside of the one.

  In accordance with the fitting guide, the output shaft of the second universal joint is oscillated and displaced in the forward downward direction from the predetermined front rising posture toward the fitting posture suitable for fitting with the input shaft of the working device. At the same time, the left and right rear links come to swing up and down, so that the output shaft of the second universal joint is fitted with the input shaft of the work device in a fitting posture suitable for fitting with the input shaft of the work device. Can be positioned at a height suitable for fitting.

Therefore, the transmission system can be reliably connected to the work device in conjunction with the connection of the mid-mount type work device by traveling forward .

As one of the means for making the present invention more suitable,
The swing limiting mechanism is configured by the relay transmission shaft provided with a stopper that limits extension of the relay transmission shaft.

  According to this means, the swing limiting mechanism is configured by, for example, constructing a receiving member that limits the upward swinging of the output shaft from a predetermined forward rising posture by receiving the output shaft over the left and right rear links. Compared to the case, the swing limiting mechanism can be configured to be small and simple.

It is a left view of a passenger work vehicle. It is a cross-sectional top view of the principal part which shows the connection structure of a mower. It is a left view of the passenger work vehicle which shows the state just before connecting a mower. It is a vertical left view of the principal part which shows the state just before connecting a moor. It is a vertical left view of the principal part which shows the state which connected and grounded the mower. It is the vertical left side view of the principal part which shows the state which connected and moored the mower. It is a vertical left view of the principal part which shows the removal process of a mower.

  Hereinafter, as an example of an embodiment for carrying out the present invention, an embodiment in which a working device connection structure for a passenger work vehicle according to the present invention is applied to a tractor that is an example of a passenger work vehicle will be described with reference to the drawings.

  As shown in FIG. 1, the tractor exemplified in the present embodiment includes a driving portion 2 in the front half of the body frame 1, and forms a boarding operation portion 3 in the rear half of the body frame 1. A front wheel 4 that can be driven to the left and right of the driving unit 2 is provided, and a rear wheel 5 that is a braking wheel that can be braked to the left and right of the riding operation unit 3 to provide a four-wheel drive type. doing.

  The vehicle body frame 1 has a water-cooled diesel engine (hereinafter referred to as an engine) 7 connected to a rear portion of a front frame portion 6, a clutch housing 8 connected to a rear lower portion of the engine 7, and a rear portion of the clutch housing 8. A transmission case (hereinafter referred to as a T / M case) 10 is connected via an intermediate frame portion 9 so as to extend across the tractor.

  The prime mover 2 is configured by disposing an engine 7 and a radiator 12 in an engine room formed by a hood 11. The boarding driver 3 is provided with a steering wheel 13 and a driver seat 14 for front wheel steering.

  The power from the engine 7 is supplied from a hydrostatic continuously variable transmission (hereinafter referred to as HST) connected to the front portion of the T / M case 10 through a main clutch (not shown) provided in the clutch housing 8. This is transmitted to 15 input shafts (not shown). Then, the power from the output shaft (not shown) of the HST 15 is transmitted to a gear type transmission (not shown) provided inside the T / M case 10 for traveling, and the power from the gear type transmission is obtained. Is branched into a front wheel drive and a rear wheel drive inside the T / M case 10. Power for driving the front wheels is transmitted from the inside of the T / M case 10 to the left and right front wheels 4 via a front wheel transmission system (not shown) extending from the left and right front wheels 4. Power for driving the rear wheels is transmitted from the inside of the T / M case 10 to the left and right rear wheels 5 via a rear wheel transmission system (not shown) extending from the left and right rear wheels 5. On the other hand, the power from the input shaft of the HST 15 is rearward provided at the rear end portion of the T / M case 10 via a work transmission system (not shown) provided inside the T / M case 10 for working. The first power take-off shaft 16 and the forward second power take-out shaft 17 provided at the bottom of the T / M case 10 are transmitted.

  As shown in FIGS. 1 and 3, at the rear of the T / M case 10, a pair of left and right lift arms 18 that swing up and down by the operation of a lift cylinder (not shown) provided therein, and these A first link mechanism 19 that moves up and down in conjunction with the vertical swing of the lift arm 18 is provided. A single acting hydraulic cylinder is adopted as the lift cylinder. The first link mechanism 19 includes a pair of left and right lower links 20 that enable attachment and detachment of a working device (not shown) such as a rotary tiller or a plow.

  That is, by connecting and equipping the first link mechanism 19 with a working device such as a rotary tiller or a plow, the working device can be installed at the rear of the tractor so that it can be raised and lowered by operating the lift cylinder. Can do. And when the working device is a drive type operated by power from a tractor, such as a rotary tiller, an input shaft (not shown) of the working device is used as an external transmission shaft (not shown). By connecting to the first power take-off shaft 16 via the above, the working power taken out from the first power take-out shaft 16 can be transmitted to the work device to operate the work device.

  Although not shown, the lift cylinder is a supply state in which a switching valve that switches the flow of oil to the lift cylinder based on the operation of the lifting lever provided in the boarding operation unit 3 supplies oil from the hydraulic pump to the lift cylinder. Is switched to the extended state in which the working device is raised by the oil from the hydraulic pump. When the switching valve is switched to a discharge state in which the oil in the lift cylinder is discharged based on the operation of the lifting lever, the switching valve is switched to a contracted state in which the working device is lowered due to the weight of the working device. Based on the operation of the lift lever, when the switching valve is switched to a supply / discharge stop state in which oil supply / discharge to / from the lift cylinder is stopped, the switching valve is switched to an expansion / contraction stop state in which the working device is stopped to move up and down.

  As shown in FIGS. 1 to 6, the lower abdomen (hereinafter referred to as the lower abdomen of the tractor) between the left and right front wheels 4 and the left and right rear wheels 5 of the tractor is an example of a mid-mount working device. A mid-mount mower (hereinafter referred to as mower) 21 is equipped. Between the vehicle body frame 1 and the mower 21, a second link mechanism 22 that supports the mower 21 so as to be lifted and lowered is interposed. The second link mechanism 22 includes a pair of left and right front links 23 extending from the front of the vehicle body frame 1 to the front end of the mower 21 in a rearward downward tilt posture, and the mower 21 from the front and rear intermediate portion of the vehicle body frame 1 in a rearward downward tilt posture. A pair of left and right rear links 24 and the like extending across the rear part are provided, and the mower 21 is configured in a parallel link type that moves up and down in a predetermined mowing posture. The left and right rear links 24 are linked to the left and right lower links 20 of the first link mechanism 19 via a linkage mechanism 25.

  The linkage mechanism 25 is a pair of left and right rotating shafts 26 that are mounted on the vehicle body frame 1 so as to be rotatable, and a pair of left and right mounted integrally on the rotating shaft 26 in a state of extending from the rotating shaft 26 toward the front of the vehicle body. One linkage arm 27, a pair of left and right second linkage arms 28 integrally mounted on the pivot shaft 26 in a state of extending from the pivot shaft 26 toward the upper side of the vehicle body, and a pair of left and right provided on the rear portion of the T / M case 10. A pair of left and right first linkage rods 30 that link the interlocking arm 29, the left and right first linkage arms 27 to the free end side of the corresponding rear link 24, and a pair of left and right second linkage arms 28 are linked to the corresponding linkage arms 29. And a pair of left and right second linkage rods 31. The left and right interlocking arms 29 are externally fitted to the support shafts 32 of the corresponding lower links 20 so as to be able to swing relative to each other. At the upper part of the left and right interlocking arms 29, an abutting piece 29A that contacts one side from above is bent at the upper edge of the corresponding lower link 20 of the first link mechanism 19 due to the weight of the left and right rear links 24, and the like.

  That is, the mower 21 is connected to the vehicle body frame 1 via the second link mechanism 22, and the second link mechanism 22 is linked to the first link mechanism 19 via the linkage mechanism 25. The lower abdomen of the tractor is equipped to move up and down.

  As shown in FIGS. 1 and 3 to 6, the rotating shaft 26 is integrally provided with a single third linkage arm 33 extending toward the rear of the vehicle body. The intermediate frame portion 9 of the vehicle body frame 1 receives the third linkage arm 33 that swings up and down in conjunction with the downward swing of the left and right rear links 24, thereby preventing the left and right rear links 24 from swinging downward. A receiving device 34 is provided. The receiving device 34 includes a gripping portion 34A that can be rotated around the vertical axis from the boarding operation unit 3, and a cylindrical receiving portion 34B that rotates integrally with the gripping portion 34A around the vertical axis. Etc. And the lower edge of the receiving part 34B which receives the 3rd linkage arm 33 is formed in the step shape from which height differs in the circumferential direction.

  With this configuration, the holding height position of the third linkage arm 33 by the receiving tool 34 can be arbitrarily determined by holding the holding part 34A from the boarding operation unit 3 and rotating the receiving tool 34 about the longitudinal axis. The lower limit position of the left and right rear links 24 relative to the vehicle body frame 1 (hereinafter referred to as the lower limit position of the rear links 24) can be easily changed.

  That is, the lower limit height of the mower 21 relative to the vehicle body frame 1 by changing the setting of the lower limit position of the left and right rear links 24 by the third linkage arm 33 and the catch 34 (hereinafter referred to as the lower limit height of the mower 21). A lower limit setting mechanism 35 is set.

  As described above, in the linkage mechanism 25 that links the left and right rear links 24 to the left and right lower links 20, the contact pieces 29A of the left and right interlocking arms 29 are separated from the upper edge of the corresponding lower links 20 from above. In the lower limit setting mechanism 35, the lower link setting mechanism 35 is configured to receive the third linkage arm 33 that swings upward and downward by a receiving device 34 disposed above the lower link setting mechanism 35. When the mower 21 equipped on the vehicle rides on a partially raised portion or the like of the work site, the ascent displacement of the mower 21 due to the upward swing of the second link mechanism 22 with respect to the vehicle body frame 1 can be allowed. Even in the state where the lowering and swinging of the left and right rear links 24 is prevented by the receiving member 34, the left and right lower links 20 can be lowered and swung by the operation of the lift cylinder.

  As shown in FIGS. 1 to 6, the mower 21 includes a corresponding vertical rotation shaft 36 and three blades (not shown) that rotate integrally clockwise in plan view, and a mower deck that covers these blades from above. 38, etc. On the upper part of the mower deck 38, a transmission mechanism 39 for driving the blade is provided. In addition, left and right transmission covers 40 that cover the left and right ends of the transmission mechanism 39 from above are detachably attached. The mower deck 38 is configured such that the front upper portion 38A is formed so as to bulge upward across the left and right of the mower deck 38, so that the interior of the front upper portion 38A can be used as a conveying path 38B for mowing grass. A discharge port 38C is formed at the right end of the mower deck 38, which is the end of the transport path 38B, and a discharge cover 41 is provided.

  That is, the mower 21 discharges the grass cut by the three blades to the outside from the discharge port 38C on the right end through the transport path 38B of the front upper portion 38A in the mower deck 38 by the transport wind generated as each blade rotates. The side discharge specification is configured.

  The mower deck 38 is provided with a gauge wheel 42 whose height can be adjusted at both left and right end portions of the rear portion. In addition, guide rollers 43 are provided at the front left and right center locations and the left and right end locations. The left and right front links 23 are pivotally connected to a pair of left and right first brackets 44 that support the left and right center guide rollers 43 so as to be vertically swingable. At the rear of the moor deck 38, a second bracket 45 as a pair of left and right engaging members that enables engagement with the free end portions of the left and right rear links 24 pivotally connected to the body frame 1 so as to be swingable up and down. Is standing.

  The transmission mechanism 39 interlocks and connects the input shaft 47 extending rearward from the transmission case 46 disposed in the center of the mower deck 38, and the rotation shaft 36 disposed in the center of the mower deck 38 inside the transmission case 46 and the input shaft 47. A pair of bevel gears (not shown), a driving pulley 48 that rotates integrally with the central rotating shaft 36, left and right driven pulleys 49 that rotate integrally with the left and right rotating shafts 36 disposed on both left and right sides of the mower deck 38, and a driving pulley 48 A tension pulley 50 disposed behind the transmission pulley 50, a transmission belt 51 wound around the pulleys 48 to 50, and the like, and by transmitting the power transmitted to the input shaft 47 to each rotary shaft 36, A belt transmission type is configured to rotate each blade together with the rotating shaft 36 clockwise in plan view.

  The input shaft 47 of the transmission mechanism 39 receives power from the second power take-out shaft 17 of the tractor via the first universal joint 52, the relay transmission shaft 53 configured to be extendable, the second universal joint 54, and the like. Is communicating.

  The left and right transmission covers 40 are provided in a state having a high strength that allows the front wheel 4 to get over at a front wheel overrunning portion of the mower deck 38 in order to allow the left and right front wheels 4 to get over the mower 21. Further, when mounted on the mower deck 38, the upper surface of the front upper portion 38A of the mower deck 38 and the upper surfaces of the transmission covers 40 are configured to have substantially the same height.

  With this configuration, when the mower 21 is positioned on the lower abdomen of the tractor, the left and right front wheels 4 pass over the corresponding transmission cover 40 from the rear of the moor 21 and advance over the tractor so that the tractor moves forward. By running, the mower 21 is simply arranged on the lower abdomen of the tractor without the need to push the mower 21 between the left and right front wheels 4 and the left and right rear wheels 5 from the lateral side of the tractor. be able to.

  On the other hand, when the mower 21 is taken out from the lower abdomen of the tractor, the left and right front wheels 4 pass over the corresponding transmission cover 40 from the front of the moor 21 and ride over the reverse so that the tractor moves backward. By doing so, it is possible to easily remove the mower 21 from the lower abdomen of the tractor without having to take out the mower 21 from between the left and right front wheels 4 and the left and right rear wheels 5 to the lateral outside of the tractor. .

  A reinforcing member 55 that also serves as a guide plate for guiding the corresponding front wheel 4 across the front and rear ends of the transmission cover 40 is welded to the inner end portion of the upper surface of each transmission cover 40. Thereby, while increasing the strength of the left and right transmission covers 40, it is possible to suppress the occurrence of inconvenience that the left and right front wheels 4 are displaced in the left and right directions with respect to the left and right transmission covers 40 when getting over the mower 21. it can.

  As shown in FIG. 2, the moor deck 38 has a flat anti-slip member 56 attached to a front portion of the left and right transmission covers 40 in the front upper portion 38 </ b> A. As a result, when the vehicle travels over the tractor and moves forward, the left and right anti-slip members 56 can be used as an index, and the vehicle can travel forward and travel more easily and appropriately. In addition, the sliding of the front wheels 4 with respect to the mower deck 38 that may occur when the left and right front wheels 4 get on and off the front portion 38A of the mower deck 38 can be suppressed, and the mower 21 moves backward due to the slippage. It is possible to avoid the possibility of being pushed out.

  As shown in FIGS. 1 to 6, in the second link mechanism 22, the left and right front links 23 connect their front end portions, which are free end portions, via a left and right connecting shaft 57. And it is comprised so that engagement connection with the front-end part of the vehicle body frame 1 via the connection shaft 57 is attained. Further, between the left front link 23 and the left first bracket 44, the left and right front links 23 are returned and urged to a connecting posture in which the left and right front links 23 are inclined upwardly from the mower 21 by a predetermined angle. An urging means 58 for maintaining 57 at a predetermined height position is interposed. The biasing means 58 includes an upper spring receiving portion 23A provided on the left front link 23, a rod 59 that is pivotably connected to the left first bracket 44 in a state of passing through the upper spring receiving portion 23A, and The compression spring 60 is externally fitted to the rod 59 so as to be positioned between the upper spring receiving portion 23A and the lower spring receiving portion 59A provided in the rod 59.

  On the other hand, the front end portion of the vehicle body frame 1 functions as an engagement member that engages with the connecting shaft 57 of the second link mechanism 22 from the rear as the left and right front wheels 4 travel forward after the mower 21 is passed. A pair of left and right brackets 61 formed as described above is suspended. Each bracket 61 is formed with a recess 61A as an engaging portion that is recessed backward from the front end thereof. Further, on the front side of each recess 61A, upper and lower guide portions 61a and 61b for guiding the connecting shaft 57 to an appropriate height as the vehicle travels forward, and a receiving portion 61c for receiving the connecting shaft 57 having an appropriate height. It has.

  That is, the left and right brackets 61 on the tractor side and the connecting shaft 57 on the mower side cause the connecting shafts 57 to be recessed in the respective brackets 61 as the left and right front wheels 4 travel forward from the rear of the moor 21 over the mower 21. A first engagement connection that engages and connects the free end portions of the left and right front links 23 on the mower side to a predetermined position of the vehicle body frame 1 by engaging and guiding 61A to reach the receiving portion 61c at the rear end of the recess. Mechanism A is configured.

  As shown in FIGS. 1 to 7, left and right support shafts 62 are provided at the rear ends of the left and right rear links 24 across the left and right rear links 24. The support shaft 62 passes through the rear end portions of the left and right rear links 24 in a rotatable manner. The left and right end portions of the support shaft 62 projecting laterally outward from the left and right rear links 24 are engaged and connected between the free end portions of the left and right rear links 24 and the left and right second brackets 45 provided in the mower 21. It is comprised so that it may function as the engaging pin 64 which is an engaging part which enables this.

  On the other hand, the left and right second brackets 45 are formed with recesses 45 </ b> A as engaged portions that enable engaging connection with the free ends of the left and right rear links 24. The recess 45A is formed in the upper part of each second bracket 45 so as to be recessed forward from the rear end of the second bracket 45 to allow the engagement pin 64 to be engaged from behind.

  That is, the left and right engagement pins 64 are moved by the tractor-side support shaft 62 and the mower-side left and right second brackets 45 as the left and right front wheels 4 move forward from the rear of the mower 21 and move forward. The engaging end of the left and right rear links 24 on the tractor side is engaged with and connected to a predetermined position of the mower 21 by engaging and guiding the corresponding recessed portion 45A of the second bracket 45 to reach the front end portion of the recessed portion 45A. A two-engagement coupling mechanism B is configured.

  Each second bracket 45 is equipped with a lock mechanism 65 that maintains the free end portions of the left and right rear links 24 and the left and right second brackets 45 in an engaged and connected state. Each lock mechanism 65 includes a lock arm 66 connected to the second bracket 45 so as to be swingable up and down, and a tension spring 67 that urges the lock arm 66 to return to the lock posture. The lock arm 66 is in a locked posture such that the lock arm 66 resists the biasing force of the tension spring 67 by the contact of the engagement pin 64 with respect to the engagement pin 64 that is engaged toward the front end portion of the recess 45A. By swinging downward, the engagement pin 64 is allowed to be engaged with the front end portion of the recess 45A, and for the engagement pin 64 engaged with the front end portion of the recess 45A, By receiving the engagement pin 64 at the front end of the lock arm 66, the engagement pin 64 is set to a forward rising inclination posture so as to be held at the front end portion of the recess 45A.

  As shown in FIGS. 1 to 6, an output shaft 68 composed of a cylindrical shaft that is spline-fitted to the input shaft 47 of the mower 21 is integrally rotated with the output portion 54 </ b> A at the output portion 54 </ b> A of the second universal joint 54. Equipped in the state to do. The output shaft 68 is fitted in a holder 69 that is rotatably fitted to the support shaft 62 via a bearing 70 so as to be rotatable and non-slidable. Further, when the interlocking connection by the spline fitting with the input shaft 47 of the mower 21 is released, the weight of the relay transmission shaft 53 and the second universal joint 54 etc. causes the support shaft 62 as a fulcrum to move forward. It is configured to swing.

  The relay transmission shaft 53 is provided with a stopper (not shown) that limits its extension to a predetermined length. As a result, the relay transmission shaft 53 limits the extension to a predetermined length, so that the lower limit setting mechanism 35 sets the upward swing of the output shaft 68 when the mower 21 is disconnected from the input shaft 47. The left and right rear links 24 are configured to function as a rocking restriction mechanism C that restricts the front rising angle corresponding to the lower limit position.

  The predetermined length of the relay transmission shaft 53 is such that the output shaft 68 in a state where the connection with the input shaft 47 of the mower 21 is released when the lower limit position of the left and right rear links 24 is set to the lowest limit by the lower limit setting mechanism 35. It is set to have a minimum forward rise angle that is close to horizontal. Thereby, in a state where the output shaft 68 is not connected to the input shaft 47 of the mower 21, the front rising angle of the output shaft 68 is determined as the lower limit position of the left and right rear links 24 is increased by the lower limit setting mechanism 35. As the distance between the support shaft 62 and the cross shaft 54B of the second universal joint 54 becomes smaller, the front rising angle of the output shaft 68 becomes larger, and the fitting start end portion of the output shaft 68 with respect to the input shaft 47 of the mower 21 becomes larger. It is comprised so that the height position of the front-end part which is may become high. In the lower limit setting mechanism 35, the height position of the front end portion of the output shaft 68 that changes depending on the setting changes the mounting height of each gauge wheel 42 in the mower 21 (the length extending downward from the mower deck 38). The step of the lower edge of the staircase in the receiving portion 34B is set so as to correspond to the height position of the input shaft 47 of the mower 21 that changes according to the cutting height determined by doing so.

  The output shaft 68 of the second universal joint 54 has, at its front end, a front-expanding shape that guides the input shaft 47 of the mower 21 into the output shaft 68 during forward travel after the left and right front wheels 4 get over the mower 21. The enlarged diameter guide portion 68A is provided. Further, the length of the forward extension from the holder 69 is such that the left and right engagement pins 64 are engaged with the corresponding recesses 45A of the second bracket 45 when the mower 21 is mounted by traveling forward. The diameter-expanding guide portion 68A is configured to be fitted to the input shaft 47 of the mower 21.

  From the above configuration, when the mower 21 is connected to the lower abdomen of the tractor, first, the lower limit setting mechanism 35 and the lifting lever are operated, and the output shaft 68 provided at the free end portion of the left and right rear links 24 is operated. The lower limit positions of the left and right rear links 24 are changed so that the height position becomes an appropriate height for mower connection, and the left and right rear links 24 are lowered to the lower limit position.

  Incidentally, the appropriate height for connecting the output shaft 68 to the mower is the height at which the inner peripheral surface of the diameter-expanding guide portion 68A of the output shaft 68 in the forward rising and inclined posture faces the input shaft 47 of the mower 21 in the longitudinal direction of the vehicle body. It is. The height of the input shaft 47 of the mower 21 changes according to the cutting height determined by the mounting height of each gauge ring 42 in the mower 21 (the length extending downward from the mower deck 38).

  Next, the vehicle travels forward as described above. Then, at the front end portion of the tractor, as the left and right front wheels 4 move over the mower 21, the left and right brackets 61 on the tractor side are moved by the upper and lower guide portions 61a and 61b. The side connecting shaft 57 is guided to an appropriate height with respect to the receiving portion 61 c of each bracket 61. As the tractor reaches the connection position of the mower 21, the left and right brackets 61 receive the connection shaft 57 by their receiving portions 61 c (see FIGS. 1 and 5).

  Further, in the middle part of the front and rear of the tractor, the inner peripheral surface of the enlarged diameter guide portion 68A of the output shaft 68 contacts the input shaft 47 of the mower 21 as the left and right front wheels 4 move forward after the motor 21 has been moved forward. In contact therewith, the input shaft 47 of the mower 21 is guided into the output shaft 68. In accordance with this guidance, the left and right rear links 24 swing up and down, and the relay transmission shaft 53 swings up and down while contracting, so that the output shaft 68 is set to each rear link set by the lower limit setting mechanism 35. The posture is changed from a forward rising inclined posture corresponding to the lower limit position of 24 to a fitting posture suitable for fitting with the input shaft 47, and externally fitted (spline fitting) so as to be able to transmit to the input shaft 47 [FIGS. reference〕.

  On the other hand, in parallel with the connection of the transmission system, the left and right engagement pins 64 provided at the free ends of the left and right rear links 24 move to the left and right provided to the mower 21 as the rear links 24 rise and swing. As the output shaft 68 is spline-fitted to the input shaft 47, the lock arm 66 of the corresponding lock mechanism 65 is pulled as the second bracket 45 is raised to a height suitable for engagement with the recess 45A. While pushing down against the urging force of the spring 67, it engages with the corresponding recess 45A of the second bracket 45 from behind. When the left and right engaging pins 64 reach the front end portions of the corresponding recesses 45A of the second bracket 45 by this engagement, the lock arms 66 of the respective lock mechanisms 65 are accordingly energized by the tension springs 67. By returning to the locked posture and receiving the corresponding engagement pin 64 from the rear lower side by the front end, the corresponding engagement pin 64 is prevented from being detached from the front end portion of the recess 45A of the second bracket 45 [FIG. To 5 and FIG.

  Further, by preventing the separation, the output shaft 68 of the second universal joint 54 is externally fitted so as to be able to transmit to the input shaft 47 of the mower 21 and the mower side connecting shaft 57 is connected to the left and right brackets 61 on the tractor side. Is prevented from detaching from the receiving portion 61c.

  In other words, by performing the above-described overriding traveling, the mower 21 can be easily and surely connected and held in a state in which the mower 21 can be raised and lowered to the lower abdomen of the tractor, and the transmission system is easily and reliably connected to the mower 21. [Refer to FIG. 1, FIG. 2, FIG. 5 and FIG. 6].

  As shown in FIGS. 1, 2, and 7, the lock arm 66 of each lock mechanism 65 includes a linkage pin 66 </ b> A that protrudes laterally outward at the front end portion thereof. The boarding operation unit 3 is provided with a release pedal 71 that enables the left and right lock mechanisms 65 to be released from the boarding operation unit 3. The release pedal 71 swings up and down about a left and right support shaft 72 provided on the vehicle body frame 1, and contacts a stopper 74 provided on the vehicle body frame 1 by the action of a torsion spring 73 fitted on the support shaft 72. It is configured to automatically return to the stepping release position that touches it. The support shaft 72 is equipped with left and right linkage arms 75 that swing together with the release pedal 71 via the support shaft 72. The left and right linkage arms 75 are L-shaped in a side view and are arranged so as to swing up and down at the free ends of the left and right rear links 24 via left and right release wires 76 routed along the left and right rear links 24. The operation arm 77 is linked. In a state where the release pedal 71 is located at the depression release position, the left and right operation arms 77 are separated upward from the link pins 66A of the corresponding lock arm 66 by the action of the corresponding torsion spring 78, and the left and right tension springs 67 The lock pins 66A of the corresponding lock arm 66 are allowed to resist the action of the corresponding torsion spring 78 in conjunction with the depression operation of the release pedal 71 while allowing the lock arms 66 to return to the locked posture by urging. Is pressed from above, and the left and right lock arms 66 are switched from the locked position to the unlocked position against the bias of the tension spring 67.

  In other words, by depressing the release pedal 71, the lock mechanism 65 releases the maintenance connection state between the free end portions of the left and right rear links 24 on the tractor side and the left and right second brackets 45 on the mower side. can do. As a result, the moor side connecting shaft 57 is disengaged from the recess 61A of the left and right brackets 61 on the tractor side and the left and right rear sides of the tractor side from the recess 45A of the left and right second bracket 45 on the tractor side due to reverse travel. The disengagement of the engagement pin 64 of the link 24 and the disengagement of the output shaft 68 on the tractor side from the input shaft 47 of the mower 21 can be permitted.

  Accordingly, when the mower 21 is removed from the lower abdomen of the tractor, first, the elevating lever is operated to the lowered position, and the mower 21 is lowered by its own weight to be grounded. Next, after depressing the release pedal 71 to release the lock by each lock mechanism 65 and performing the above-described overriding backward traveling, the first traveling by the backward traveling until the left and right front wheels 4 ride on the mower 21 is performed. Engagement connection between the left and right brackets 61 on the tractor side by the engagement connection mechanism A and the connection shaft 57 on the mower side, and a free end portion of the left and right rear links 24 on the tractor side by the second engagement connection mechanism B and the mower side The engagement connection with the left and right second brackets 45 and the spline fitting between the output shaft 68 on the tractor side and the input shaft 47 of the mower 21 can be easily released. Then, when the left and right front wheels 4 get over the mower 21 by the subsequent reverse travel, the mower 21 can be easily taken out from the lower abdomen of the tractor.

  [Another embodiment]

[1] The riding work vehicle may be a riding mower configured so that the mid-mount mower 21 can be attached and detached. Also, a mower dedicated hydraulic lifting mechanism, or a mower dedicated manual lifting mechanism that manually lifts and lowers the mower 21 may be provided.

[2] The mid-mount working device 21 may be a grass collecting device configured to be able to ride over the left and right front wheels 4.

[3] The mid-mount mower 21 may be configured to have a rear discharge specification in which the cut grass is discharged rearward from a discharge port formed at the rear end of the mower. The grass cut by the blade may flow in the mower deck 38 and chopped, and then fallen to the ground below from the bottom opening of the mower deck 38. Further, the number of blades provided in the mid-mount mower 21 and the transmission structure for the blades can be variously changed.

[4] As the engagement connecting mechanism B, a concave portion formed so as to be recessed backward from the front side to the free end portion of the left and right rear links 24 becomes an engaging portion 64, and the concave portion can be engaged from the front side. The left and right engaging pins provided in the work device 21 may be configured to be the engaged portion 45A.

[5] The input shaft 47 of the work device 21 may be constituted by a cylindrical shaft provided with a diameter-expanding guide portion having a pre-expanded shape that guides the output shaft 68 on the tractor side.

[6] As the swing restriction mechanism C, for example, a receiving member that restricts forward swinging of the output shaft 68 from a predetermined forward lift posture by receiving the output shaft 68 or the holder 69 is used as the left and right rear links. It may be configured by erection over 24.

  The working device connection structure for a passenger work vehicle according to the present invention is applied to a passenger work vehicle such as a tractor or a riding mower that is detachably provided with a mid-mount working device configured to be able to ride over the left and right front wheels. Can do.

DESCRIPTION OF SYMBOLS 1 Body frame 4 Front wheel 5 Rear wheel 17 Power take-out shaft 21 Working device 22 Link mechanism 23 Front link 24 Rear link 45A Engagement part 47 Input shaft 52 First universal joint 53 Relay transmission shaft 54 Second universal joint 62 Support shaft 64 Engagement portion 68 Output shaft 68A Diameter expansion guide portion 69 Holder B Engagement connection mechanism C Swing limit mechanism

Claims (2)

An up-and-down swing type link mechanism in which a mid-mount working device arranged between a pair of left and right front wheels and a pair of left and right rear wheels is provided on a body frame with a pair of left and right front links and a pair of left and right rear links. It can be moved up and down via
The power from the power take-out shaft provided at the rear of the vehicle body is transmitted to the rearward input shaft provided in the working device via the first universal joint, the relay transmission shaft configured to be extendable and the second universal joint. Configured as
The left and right rear links are pivotally connected to the body frame,
The engagement device includes an engagement portion provided at the free end portion of the pair of left and right rear links as the pair of left and right front wheels travels over the work device from behind the work device and travels forward. An engagement connecting mechanism for engaging and connecting to the joint portion;
A holder that rotatably supports the output shaft of the second universal joint that can be intermittently fitted to the input shaft is swung up and down via the left and right support shafts on the free ends of the left and right rear links. Equipped so that the output shaft swings up and swings with the release of the input shaft,
One of the output shaft and the input shaft is constituted by a cylindrical shaft provided with a diameter-expanded guide portion having a pre-expanded shape that guides the other of them into the interior,
During forward traveling after the pair of left and right front wheels have passed over the working device , the other fitting start end is located in a guide region of the enlarged diameter guide portion provided on one of the output shaft and the input shaft. A working device connection structure for a passenger work vehicle, comprising a swing restriction mechanism that prevents the output shaft from swinging upward from a predetermined forward lift posture so that a state can be obtained.   The work device connection structure for a passenger work vehicle according to claim 1, wherein the swing restriction mechanism is configured by the relay transmission shaft provided with a stopper that restricts extension of the relay transmission shaft.

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