1. Field of the Invention
The present invention relates to a mid-mount mower having a mower unit disposed under a vehicle body between front wheels and rear wheels.
2. Description of the Related Art
In a mid-mount mower, a blade housing covering a rotary blade is connected to a lift link mechanism having a front link and a rear link attached to a vehicle body and spaced apart from each other in a vehicle front/rear direction. With this, the blade housing can be lifted up/down between a lowered working position and an elevated non-working position. When a maintenance/inspection of the mower unit or an operation other than a grass mowing operation is to carried out, the mower unit is dismounted from the vehicle body. It is very troublesome to carry out a connecting/disconnecting operation thereof in a limited space between the front wheels and the rear wheels. For this reason, it has been proposed to carry out at least some steps of the connecting/disconnecting operation in an automated manner.
For instance, in the case of a mid-mount mower disclosed in Japanese Unexamined Utility Model Application Publication No. 4-110428 (FIG. 1, FIG. 3) (Patent Document 1), in association with a forward traveling of the vehicle body, left and right front wheels roll over a blade housing, with utilizing a front wheel guide plate of this blade housing, to be positioned eventually at the body portion of a tractor. Then, in association with a final forward traveling, connection pins provided at free ends of a pair of left and right rear links are guided by openings formed at hook portions of a pair of left and right support stays provided in the blade housing and engaged into the deepest parts thereof. Then, lock arms provided in the respective support stays come into engagement with the connection pins with spring action, thus retaining the connection pins against inadvertent removal thereof, whereby the respective connection pins provided on the side of the vehicle body are connected to the respective support stays provided on the side of the mower. Thereafter, with establishment of connection between the front link and the front-side support stays, the connecting operation is completed. With the connecting arrangement disclosed in this Patent Document 1, connection of the front link needs to be carried out manually after connection of the rear link. After the connection pins of the pair of left and right rear links are guided by the openings of the hook portions of the blade housing and engaged into the deepest parts thereof, connection is established between the vehicle body and the blade housing. Simultaneously, engagement is established also between a clutch driving member of the vehicle body and a clutch driven member of the blade housing, thus enabling power transmission from the vehicle body to the blade housing. Under this condition, as lock arms provided in the respective support stays come into engagement with the connection pins by a spring action, thereby to retain the connection pins against inadvertent removal thereof, the respective pins of the vehicle body are connected to the respective support stays of the mower. Thereafter, with establishment of connection between the front links and the front-side support stays, the connecting operation is completed. In this way, in the case of the connecting arrangement disclosed in this Patent Document 1, connection between the vehicle body and the blade housing and connection for power transmission are effected simultaneously.
In Japanese Unexamined Patent Application Publication No. 10-339169 (FIG. 3, FIG. 4), there is disclosed an arrangement in which a hitch pin provided in a front link and a hitch pin provided in a rear link are automatically connected simultaneously with front and rear hitch brackets (support stays) provided in a mower deck (blade housing). However, with this arrangement, in the hitch brackets, there are only formed elongate holes opened along the vehicle body front/rear direction. Thus, for this connecting operation, a high-precision positioning is required between the mower deck and the vehicle body. Further, as an automatic connection arrangement relative to the mower deck is incorporated in a lift link mechanism, restriction is imposed on the designing of the structure of the lift link mechanism. For this reason, this automatic connection arrangement cannot be directly retrofitted with a conventional existing lift link mechanism. Moreover, with this connection arrangement, three points of the front-side hitch pin, the rear-side hitch pin and an output shaft side coupling need to be positioned with precision in three-dimensional manner with three points of the front-side hitch bracket, the rear-side hitch bracket and an input shaft side coupling, respectively. Hence, this connecting operation is difficult.
The U.S. Pat. No. 7,877,972 (FIG. 2, FIG. 4) and the U.S. Pat. No. 823,487 (FIG. 2, FIG. 4) too disclose automatic connection arrangements between a lift link mechanism and a mower deck (blade housing), including an automatic connection of power transmission paths. However, in these arrangements too, the automatic connection arrangement for the mower deck is integrally incorporated in the lift link mechanism. This results in specialization or peculiarity of the link mechanism per se. Thus, when this automatic connection arrangement is employed, it is difficult to use a conventional lift link mechanism without any modification thereof. Further, as connection between the vehicle body and the blade housing and connection for power transmission need to be established simultaneously, a high skill and/or experience is required for the connecting operation.
USPTO Backgrounds
USPTO Backgrounds