Pressure accumulator volume switch-over valve (Direct Disc option

Key to diagram

Item Designation

B2 Ground pressure oil pressure sensor

Remark

K Face end of cylinders Ø75 µm R Rod end of cylinders Face end Ø 75 mm - Connecting rod area Ø 50 mm P2 Pressurised oil from front attachment raise/lower main valve

T Tank connection Return line

X Locking pin to avoid switching over under load, resulting in unwanted lowering of the front attachment.

351 Front attachment raise/lower hydraulic cylinder 511 Front attachment relief accumulator 40 bar

612 Front attachment load switch-over valve

Description of function

Task When lifting lightweight and heavy front attachments, the hydraulic pressure in the Front attachment raise/lower cylinders (351) is kept at the same level. Benefit: Improved response of Contour system and of ground pressure control with an accumulator. This is made possible by the Front attachment load switch-over valve (612) switching over to different pressure surfaces in the hydraulic cylinders (351). Figure A This position is selected for lightweight front attachments such as pick-up and 4-row maize header. Effective hydraulic pressure area in the Raise/lower front attachment hydraulic cylinders (351): Face end minus rod end = Connecting rod area Ø 50 mm. Figure B Switching position to allow actuating the Front attachment load switch-over valve (612). To do this, the front attachment must be lowered and the hydraulic pressure at port P6 must be completely relieved. (pressure display in CIS shows no pressure.) The spring (see X) pushes the safety pin in and the change-over lever of the Front attachment load switch-over valve (612) can be set to the other position. Figure C This position is used for heavy front attachments such as maize headers, 6row and 8-row RU maize headers and cutterbars. The rod end of the hydraulic cylinders is connected with the tank. The effective hydraulic pressure surface in the Front attachment raise/lower hydraulic cylinders (351) is the face end Ø 75 mm.