Title of Invention

LOWER LINK PIVOT SHAFT SUPPORTING APPARATUS

Abstract

ABSTRACT OF DISCLOSURE A lower link pivot shaft supporting apparatus of the double-end supported type for a pivot shaft for oscillatably supporting a lower link adapted to connect a work implement to a tractor. The apparatus comprises a first support unit (21) for receiving one end portion (20b) of the pivot shaft (20) and a second support unit (22) for receiving the other end portion (20c) of the pivot shaft (20). The first support unit (21) includes a connecting bracket (21b) removably fixed to a vehicle frame (9) of the tractor, and a bearing portion (21a) connected to the connecting bracket (21b) and removably receiving the one end portion (20b) of the pivot shaft (20).

Full Text

LOWER LINK PIVOT SHAFT SUPPORTING APPARATUS BACKGROUND OF THE INVENTION Filed of the Invention The present invention relates to a lower link pivot shaft supporting apparatus of the double-end supported type for a pivot shaft for oscillatably supporting a lower link adapted to connecting a work implement to a tractor. Description of the Related Art One example of a tractor equipped with a lower link is known from Japanese Unexamined Patent Application Publication No. 2000-37108 (paragraph 0035, 0037, 0038; Figs. 3 and 4). This tractor includes a link mechanism provided rearwardly of a vehicle body, and a tiller rotary connected thereto through the link mechanism. The link mechanism includes a top link and a right and left pair of lower links. The right and left pair of lower links are supported by a pivot shaft mounted on the vehicle body to be vertically oscillatable. The pivot shaft is mounted on the vehicle body as a cantilever type. Thus, each of the lower links is attachable and detachable only by removing a retainer pin or a retainer screw attached to a free end of the pivot shaft for retaining the lower link. However, when the pivot shaft is supported in the cantilever manner, the mechanical strength may sometimes decline depending on the type and/or the size of the work implement connected to the lower links. SUMMARY OF THE INVENTION The object of the present invention is to provide a lower link pivot shaft supporting apparatus capable of easily attaching and detaching lower links that is effectively endurable even if a great force is applied through the lower links. In order to achieve the above-noted object, the present invention provides a lower link pivot shaft supporting apparatus of the double-end supported type for a pivot shaft for oscillatably supporting a lower link adapted to connect a work implement to a tractor, comprising a first support unit for receiving one end portion of the pivot shsift and a second support unit for receiving the other end portion of the pivot shaft. The first support unit includes a connecting bracket removably fixed to a vehicle frame of the tractor, and a bearing portion connected to the connecting bracket and removably receiving the one end portion of the pivot shaft. With the lower link pivot shaft supporting apparatus in accordance with the present invention, it is possible to bear a load applied to the pivot shaft when the work implement is connected to the vehicle body in the double-end supported manner. This can diminish the chance of deforming or bending or damaging the pivot shaft as compared with the pivot shaft mounted in the cantilever manner even when the same amount of the load is applied. Further, when one of the support units is removed from the pivot shaft and the vehicle frame, the pivot shaft can have a free end and the lower link can be attached and detached to/from the free end. Thus, the lower link can be easily attached or detached only by removing ' one of the support units, while the pivot shaft can be rigidly maintained in the double-end supported manner when the work implement is connected to the vehicle body. According to one preferred embodiment of the present invention, the second support unit is formed as a mounting bracket removably fixed to the vehicle frame, and the mounting bracket is integrally fixed with the other end portion of the pivot shaft. With this construction, when the second support unit is detached from the vehicle frame after the first support unit is detached from the vehicle frame, the second support unit can be taken out together with the pivot shaft. The second support unit is integrally fixed with the pivot shaft, which can reduce the chance of losing the pivot shaft in the inspection and maintenance. Other features and advantages of the present invention will be apparent from the detailed description of the preferred embodiments set forth below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side elevation of a tractor equipped with a lower link pivot shaft supporting apparatus in accordance with the present invention; Fig. 2 is a top plan view of the tractor; Fig. 3 is a rear view of a rear portion of the tractor; Fig. 4 is a rear view of the lower link pivot shaft supporting apparatus; Fig. 5 is a side view of the lower link pivot shaft supporting apparatus; Fig. 6 is an explanatory view showing a mode for detachment of a lower link and replacement of a pivot shaft; and Fig. 7 is a side view of the lower link pivot shaft supporting apparatus with the lower link being detached. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will be described in detail hereinafter with reference to the accompanying drawings. Fig. 1 is a side elevation of a tractor equipped with one example of a lower link pivot shaft supporting apparatus in accordance with the present invention. Fig. 2 is a top plan view of the tractor. As shown in the drawings, the tractor comprises a right and left pair of dirigible and drivable front wheels 1, a right and left pair of drivable rear wheels 2, a motor section having an engine 3 mounted forwardly of a vehicle body, and a driver's section having a driver's seat 5 mounted rearwardly of the vehicle body between a right and left pair of rear wheel fenders 4, thereby providing a self-propelled vehicle. The self-propelled vehicle includes a link mechanism 10 having a right and left pair of lift arms 11, and a PTO shaft 7. The link mechanism and the PTO shaft are mounted rearwardly of a vehicle frame 6 of the self-propelled vehicle. This tractor is constructed as a riding-type tiller in which a rotary cultivating device (not shown) is connected to a rear portion of the vehicle body through the link mechanism 10, allowing output from the engine 3 to be transmitted to the rotary cultivating device through the PTO shaft 7. In this way, this tractor acts as any kind of riding-type work vehicle by connecting any kind of work implement to the rear portion of the vehicle body. As shown in Fig. 1, the vehicle frame 6 includes the engine 3, a front case 8 connected rearwardly of the engine 3, a transmission case 9 connected rearwardly of the front case 8, and a front wheel support frame 6a connected to the underside of the engine 3. Fig. 3 is a rear view of the rear portion of the vehicle body. As shown in Figs. 1 and 3, the transmission case 9 includes a transmission case body 9a connected to the front case 8, and rear wheel driving cases 9b provided adjacent opposite laterail sides of the transmission case body 9a. The rear wheels 2 are drivably supported by the rear wheel driving cases 9b, while the PTO shaft 7 is drivably supported by a rear portion of the transmission case body 9a. The front case 8 accommodates a main clutch mechanism (not shown) receiving output from the engine 3, and a power transmission mechanism (not shown) for transmitting output from the main clutch mechanism to a running transmission (not shown) and a working transmission (not shown) arranged in the interior of the transmission case 9. As shown in Fig. 2, the link mechanism 10 includes, in addition to the right and left pair of lift arms 11, a right and left pair of lower links 12, a left lift rod 13 connecting the left lift arm 11 to the left lower link 12, a right lift rod 13 connecting the right lift arm 11 to the right lower link 12, and a top link 14. The right and left pair of lift arms 11 are supported to an upper portion of the transmission case body 9a through a single rotary support shaft 15 to be vertically oscillatable. The right and left pair of lift arms 11 are operatively connected to a vertically movable cylinder (not shown) arranged in the interior of the transmission case body 9a through the rotary support shaft 15. Each of the right and left pair of lower links 12 is supported to the underside of the transmission case 9 at one lateral end portion thereof to be vertically oscillatable. The top link 14 is supported to a right and left pair of brackets 16 fixed to the transmission case body 9a to be vertically oscillatable. The link mechanism 10 is adapted to connect the work implement to the transmission case 9 acting as the vehicle frame 6 to be vertically movable after distal ends of the right and left pair of lower links 12 and a distal end of the top link 14 are connected to the work implement. The right and left lower links 12 are vertically oscillated relative to the transmission case 9 through the lift rods 13 by the right and left pair of lift arms 11 that are vertically oscillated by the vertically movable cylinder, thereby vertically operating the work implement. Fig. 4 is a rear view of the lower link pivot shaft supporting apparatus for supporting the lower links 12. Fig. 5 is a side view of the lower link pivot shaft supporting apparatus. As shown in the drawings, each lower link 12 has a spherical joint 12a at a proximal portion thereof. The spherical joint 12a is detachably fitted on a pivot shaft 20 extending transversely of the vehicle body and supported to the underside of the transmission case 9 at one lateral end thereof. This allows each lower link 12 to be supported to the pivot shaft 20 to be vertically oscillatable and freely detachable. The pivot shaft 20 includes a lower link support 20a to which the lower link 12 is attached, one end portion 20b and the other end portion 20c positioned at the outside of the lower link support 20a, respectively. The one end portion 20b of the pivot shaft 20 is received and supported by a tubular shaft-shaped bearing portion 21'a arranged at a lower end portion of a first support unit 21 mounted on the transm.ission case body 9a. The other end portion 20c of the pivot shaft 20 is supported by a second support unit 22 attached to each rear wheel driving case 9b. The first support unit 21 for supporting the one end portion 20b of the pivot shaft 20 includes a connecting bracket 21b connected to the bearing portion 21a. The connecting bracket 21b is detachably fixed to the transmission case body 9a acting as the vehicle frame 6 through two connecting bolts 23. The one end portion 20b of the pivot shaft 20 is removably inserted into the bearing portion 21a. The second support unit 22 for supporting the other end portion 20c of the support shaft 20 is detachably connected to the rear wheel driving case 9b acting as the vehicle frame through three connecting bolts 24. The second support unit 22 is formed as a plate-shaped mounting bracket having a through bore 22a formed therein for receiving the other end portion 20c of the pivot shaft 20. The second support unit 22 and the pivot shaft 20 are integrally formed by welding. Thus, the second support unit 22 is attached and detached to/from the rear wheel driving case 9b in unison with the support shaft 20. Fig. 6 is a rear view showing a mode of detachment of the lower link 12 and replacement of the pivot shaft 20. Fig. 7 is a side view of the pivot shaft 20 with the lower link being detached. As shown in the drawings, the first support unit 21 is removed from the pivot shaft 20 and the transmission case body 9a when the lower link 12 is detached, which allows the pivot shaft 20 to be supported to the rear wheel driving case 9b at the other end portion 20c through the second support unit 22. On the other hand, the one end portion 20b of the pivot shaft 20 is not supported to be a free end. In this state, the lower link 12 is attachable and detachable to/from the one end portion 20b. When the pivot shaft 20 is changed, the first support unit 21 is removed from the pivot shaft 20 and the transmission case body 9a, while the second support unit 22 is removed from the rear wheel driving case 9b, thereby allowing the pivot shaft 20 to be removed from the rear wheel driving case 9b together with the second support unit 22 as well. What is claimed is: 1. A lower link pivot shaft supporting apparatus of the double-end supported type for a pivot shaft for oscillatably supporting a lower link adapted to connect a work implement to a tractor, characterized in that a first support unit (21) for receiving one end portion {20b) of the pivot shaft (20) and a second support unit (22) for receiving the other end portion (20c) of the pivot shaft (20) are provided, and that the first support unit (21) includes a connecting bracket (21b) removably fixed to a vehicle frame (9) of the tractor, and a bearing portion (21a) connected to the connecting bracket (21b) and removably receiving the one end portion (20b) of the pivot shaft (20). 2. The lower link pivot shaft supporting apparatus as claimed in claim 1, characterized in that the second support unit (22) is formed as a mounting bracket removably fixed to the vehicle frame (9), and the mounting bracket (22) is integrally fixed with the other end portion (20c) of the pivot shaft (20). 3. The lower link pivot shaft supporting apparatus as claimed in claim 2, characterized in that the mounting bracket (22) has a through bore (22a) formed therein for receiving the other end portion (20c) of the pivot shaft (20).

Documents:

2222-CHE-2008 AMENDED CLAIMS 18-07-2013.pdf

2222-CHE-2008 CORRESPONDENCE OTHERS 06-12-2013.pdf

2222-CHE-2008 CORRESPONDENCE OTHERS 18-06-2013.pdf

2222-CHE-2008 ENGLISH TRANSLATION 18-06-2013.pdf

2222-CHE-2008 EXAMINATION REPORT REPLY RECEIVED 18-07-2013.pdf

2222-CHE-2008 FORM-3 18-07-2013.pdf

2222-CHE-2008 OTHER PATENT DOCUMENT 18-07-2013.pdf

2222-CHE-2008 POWER OF ATTORNEY 18-07-2013.pdf

2222-che-2008 abstract.pdf

2222-CHE-2008 AMENDED CLAIMS 19-12-2013.pdf

2222-che-2008 claims.pdf

2222-che-2008 correspondence others.pdf

2222-che-2008 description (complete).pdf

2222-che-2008 drawings.pdf

2222-CHE-2008 EXAMINATION REPORT REPLY RECIVED 19-12-2013.pdf

2222-che-2008 form-1.pdf

2222-CHE-2008 FORM-13 19-12-2013.pdf

2222-che-2008 form-18.pdf

2222-che-2008 form-3.pdf

2222-che-2008 form-5.pdf