Hitchhook

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Side view of the trailer hitch (red) on the rear of a Claas - telescopic loader

A hitch hook ( English hitch = generally for pulling device, coupling) is a trailer coupling that is used in agricultural engineering , especially on tractors , and enables implements and, in particular, rigid drawbar trailers to be "attached below". For this purpose, the device, also known as the hitch coupling or hitch for short, is attached in the middle as the lowest point on the rear of the vehicle.

A hitch hook consists of an arched, upwardly tapering metal part and a hold-down device that automatically engages when the hitch is connected and that fixes the towing eye ("hitch ring, hitch eye, hitch eye") of the device or trailer to be attached to the hook. As a rule, the hitch hook is connected to the three-point hydraulic system so that it can move in height and is designed as a remote-controlled coupling (to be operated from the driver's seat).

Hitch hooks of various dimensions are technically described and standardized in DIN 9678 and ISO 6489-1. Depending on the size of the hitch hook, hitching eyes of the ISO 5692 and ISO 20019 standards may be attached.

In addition to the low attachment option, the easy coupling process and good angular mobility (to the tractor transverse axis and to the side) are advantageous with hitch hooks. The disadvantage is the small contact area with the towing eye, which can lead to considerable wear. Compared to the usable also with drawbar eyes bolt and drawbar couplings hitch are of simple design and inexpensive to replace. Piton-Fix couplings are even cheaper and also a little less prone to wear, but require more work when coupling and uncoupling .

Individual evidence

  1. ↑ a b c d e DLG leaflet 387: Hitching devices on tractors. (PDF; 1.7 MB) Deutsche Landwirtschafts-Gesellschaft , 2013, pp. 13–15 , accessed on February 12, 2017 .
  2. ↑ Secure connection with real game. (PDF; 850 kB) Switzerland. Agricultural Engineering Association, accessed February 12, 2017 .
  3. ↑ Current: ISO 6489-1: 2001 (Agricultural vehicles - Mechanical connections between towed and towing vehicles - Part 1: Dimensions of hitch-hooks) , German: Agricultural vehicles - Mechanical connections between towed and towing vehicles - Dimensions of hitch hooks (Tow hook) ; outdated previous standard: ISO 6489-1: 1991
  4. ↑ Current: ISO 5692-1: 2004 (Agricultural vehicles - Mechanical connections on towed vehicles - Part 1: Dimensions for hitch rings of 50/30 mm cross section)
  5. ↑ Current: ISO 20019: 2001 (Agricultural vehicles - Mechanical connections on towed vehicles - Dimensions for hitch rings)