GPA20 rear axle - Auto-hitch

Tractor hitches can be attached to different types of hitches or hooks:
- Swinging drawbar (different types)
- Clevis on adjustable scale (different types)
- Stud for semi-mounted trailer
- Pick-up hitch
Some equipment can be fitted simultaneously depending on technical possibilities, options and countries.

Presentation of the different tractor hitch hooks

A Hitch support with fast-setting scale
B Hitch support with pin-adjusting scale
C Hitch support for SAE swinging drawbar
D Hitch support with Dromone pick-up hitch
E SAE swinging drawbar
F Swinging drawbar with stud
G Standard swinging drawbar
H Roller type swinging drawbar
I Fast-setting clevis with standard pin
J Fast setting clevis with auto pin (Cramer)
K Clevis for standard pin scale
L Clevis for 20 T version pin scale
M Clevis for 6 T version pin scale

Adjusting the auto-hitch tie-rods and the control

Adjusting the tie rods
On the support, disconnect the lower clevises of the tie-rods and the control cable. Start the engine.
Assisted by an operator, activate the internal or external linkage control (if fitted) so that the linkage arms are in the maximum raised position (continuous pumping).

Compress the lower part of the hitch along the tractor centreline, as shown by "F" using a trolley jack to obtain a dimension X of 6 to 14 mm between the top of the main support and the top of the mobile plate.
Adjust the length of the tie rods by turning their square section sliders (1) in order to engage the clevises in the pins (3) of the support.

Install the pins. Remove the jack. Reconnect the control.
Check the operation of the mobile plate and the hitch locking mechanism using the lever.

Adjusting the control

On the lever 
Place the lever (1) in the "rest" position.
Adjust the nuts to obtain the same thread length (2) on each side of the support (3). Check that the cable is not pinched.

On the auto-hitch 
Screw the clevis (1) level with the threaded end of the cable (2).
Install the clevis onto rod B using the clip (3) while ensuring that the rod is in the locked position. Tighten the nut (4).
Install the sheath end (5) in the support (6) and tighten the nuts (7) and (8) so that there is no play in the cable (2) and the cable is not pinched. During adjustment, ensure that rod B remains locked.

Operating principle of the Dromone retractable hitch

The auto-hitch assembly comprises a main support (2) attached to the centre housing and a mobile plate (1) that can be raised or lowered via the adjustable tie-rods (3) of the linkage system.


Plate lowered
When the system is released by the lever in the cab, the mobile plate can be lowered to the ground by the linkage system. Once the tractor is in position, the trailer drawbar can be hitched on.

Plate raised
In this configuration, the locking safety on the retractable hitch is activated at maximum retraction, with the plate (1) previously raised and engaged. The principle involves two mechanical locks located at the rear of the main support. When the above conditions are obtained, the locks enter their respective recesses in the retractable hitch and prevent any inadvertent movement.