DEVICE FOR ADJUSTING THE POSITION OF THE THRESHER CONCAVE OF A COMBINE HARVESTER

Abstract: A thresher concave (4) for combine harvesters includes at least one elongate appendage (7) which projects substan­ tially as an extension of the thresher concave (4) beyond the rear edge (6) of the latter, and is articulated to the fixed structure (1) of the harvester about a transverse axis. The thresher concave (4) is, moreover, suspended adjustably from the fixed structure (1) of the harvester only close to its front edge (5).

Description: Device for adjusting the position of the thresher concave of a combine harvester The present invention relates to combine harvesters. In particular, the invention is concerned with combine harvesters of the type including: - a fixed structure, and - a threshing unit including a thresher cylinder mounted transversely and rotatably on the fixed structure, and a thresher concave in the form of a concave grille suspended adjustably from the fixed structure adjacent a lower part of the thresher cylinder, in which the thresher concave has a front edge and a rear edge lying along a direction substantially perpendicular to the longitudinal plane of symmetry of the harvester. In harvesters of the aforesaid type, the thresher concave is suspended from the fixed structure of the harvester at its front edge and its rear edge by means of separate adjustable ties. The distance of the thresher concave from the thresher is variable by means of these ties, so as to adapt it to the type and conditions of the harvest. This known solution has the disadvantage of being rather complicated and expensive, and of requiring relatively laborious adjusting operations, particularly when it is necessary to operate the respective adjusting ties for varying the positions of the front edge and the rear edge separately. The object of the present invention is to provide a device for adjusting the position of the thresher concave of a combine harvester, which is simple and economic and allows the adjusting operations to be carried out easily and rapidly. In order to achieve this object, the present invention has as its subject a combine harvester of the type specified initially, characterised that the thresher concave includes at least one elongate appendage which projects substantially as an extension of the thresher concave beyond its rear edge and is articulated to the fixed structure of the harvester about a transverse axis, and in that the thresher concave is adjustably suspended from the fixed structure of the harvester only adjacent its front edge. By virtue of this characteristic, the device according to the present invention has a structure which is simple and economical to manufacture with a smaller number of parts. Moreover, by means of a single adjustment, it is possible to alter the position of both front and rear edges of the thresher concave simultaneously. Further characteristics and advantages of the present invention will emerge from the following description made with reference to the appended drawings, provided purely by way of non-limiting example, in which: Figure 1 is a perspective view of the adjusting device according to the present invention, Figure 2 is a side view of the adjusting device according to the present invention, and Figure 3 is a sectional view on an enlarged scale of a detail of Figure 2. In the present description and in the claims which follow, the terms "longitudinal" and"longitudinally" refer to a direction substantially coincident with the direction of advance of the harvester during operation, and the terms "transverse" and "transversely" refer to the horizontal direction perpendicular to the longitudinal direction. In the drawings, the fixed structure 1 of the combine harvester comprises a threshing unit 2 including a thresher cylinder 3 and a thresher concave 4. The thresher cylinder 3 is mounted transversely and rotatably on the fixed structure, while the thresher concave 4, which is in the form of a concave grille with a front edge 5 and a rear edge 6, is located adjacent the lower part of the thresher cylinder 3. The thresher concave 4 is provided with two elongate appendages 7 which project substantially as extensions of the thresher concave beyond its rear edge. The free end of the appendages 7 are articulated to the fixed structure 1 of the harvester about a transverse axis by means of pins 8. A shaft 9 is supported rotatably by the fixed structure about a transverse axis by means of two supports 10. The two ends of the shaft project from the sides 11 of the fixed structure 1 through holes 12 and are each fixed to a lever 13. The free end of each lever 13 has a hole 14. Two cranked coupling members 15 are connected to respective levers 13, and each is constituted by a central cylindrical body 16 having two opposite surfaces 17, 18 and two pins 19, 20 which extend in opposite directions from the surfaces 17, 18 and have non-coincident axes. The pins 19 are inserted in the holes 14 of the levers 13. Each of the pins 20 engages an aperture 21 in the respective side 11 of the structure 1, and is rotatably mounted within a bush 22 fixed to the thresher concave close to the front edge thereof, The shaft 9 is provided at one end with an auxiliary lever 23 the free end of which supports, for pivoting about transverse axis, an element 24 having a threaded hole in which is screwed a threaded end 26 of a tie rod 25. The opposite end 27 of the tie rod 25 is shaped in the form of a handle. The tie rod is further rotatably inserted in a hole 2.8 of a ball nut 29 pivotally mounted about a transverse axis on the fixed structure 1 by means of a support bush 30. Two sleeves 31, 32 fitted onto the tie rod 25 at the sides of the ball 29 prevent axial sliding of-the tie rod relative to the nut 29 and, hence, relative to the fixed structure. The position of the thresher concave of the combine harvester is adjusted by rotation of the tie rod 25, for example, by manual operation of its end 27. This rotation results, through the element 24, in the angular displacement of the auxiliary lever 23 and, hence, of the shaft 9 about its axis of rotation; this rotation, through the drive link constituted by the levers 13 and the element 15, causes a movement of the front edge 5 and, consequently, of the rear edge 6 of the thresher concave 4 about the transverse axis of the pins 8.

Claims: CLAIMS: 1. Combine harvester, including: - a fixed structure (1), and - a threshing unit (2) including a thresher cylinder (3) mounted transversely and rotatably on the fixed structure (1), and a thresher concave (4) in the form of a concave grille suspended adjustably from the fixed structure (1) adjacent a lower part of the thresher cylinder (3), in which the thresher concave (4) has a front edge (5) and a rear edge (6) lying along a direction substantially perpendicular to the longitudinal plane of symmetry of the harvester, characterised in that the thresher concave (4) includes at least one elongate appendage (7) which projects substantially as an extension of the thresher concave (4) beyond its rear edge (6) and is articulated to the fixed structure (1) of the harvester about a transverse axis (8) and in that the thresher concave (4) is suspended adjustably from the fixed structure (1) of the harvester only adjacent its front edge (5). 2. A combine harvester as claimed in Claim 1, characterised in that the harvester further includes: - a shaft (9) rotatably supported about a transverse axis from the fixed structure (1); - a pair of levers (13) fixed to the ends of the shaft and each having its free end pivotally connected to the thresher concave (4) close to the front edge (5) thereof; - a pair of cranked coupling elements (15) interposed in the connection between the free ends of the levers (13) and the thresher concave (4), - an auxiliary lever (23) fixed. for rotation with the shaft (9) and having its free end provided with an element (24) having a threaded hole, which is pivotable relative to the free end; ; - a threaded adjusting tie rod (25)rotatably supported about a transverse axis by the fixed structure and having an end (26) screwed into the threaded hole, and - means (27) for rotating the adjusting tie rod (25) about its axis so as to cause the rotation of the auxiliary lever (23) and a consequent displacement of the thresher concave (4) relative to the fixed structure (1).

Inventors: RAINERI, GIUSEPPE
Applicants: PIETRO LAVERDA S.P.A.
Application year: 1982
Main classification: A01F12
IPC codes: A01F12