Quick coupling triangle
A quick coupling triangle (also known as triangular quick coupling, triangular coupling, tractor triangle or, after its inventor and first manufacturer, Weiste-Dreieck or Weiste-Accord-Dreieck ) is a coupling device developed in the 1960s, which is mainly used in agricultural engineering for the simple coupling of attachments can be used on tractors . During use, it is located as an additional component between the tractor lifting gear and the attachment and enables changing, even very heavy implements to be coupled and uncoupled directly from the driver's seat without tools and without an assistant.
A quick coupling triangle is a stable, inverted V-shaped or A-shaped frame ("A-frame") made of tubular steel with a rectangular cross-section. The frame is equipped with three hitch coupling points on its rear side facing the tractor and with only one coupling point on its front side facing the implement. The front coupling point usually has a self-locking lock in the form of a spring-loaded pawl . At the top of the triangle there are usually rollers that make coupling easier.
As a counterpart to the quick coupling triangle , a device triangle is used on the attachment , which is sometimes also referred to as the "device-side Weiste triangle". This is an A-frame with a U-profile and catch structure, into which the quick-release triangle is inserted from below and engages. The designation attachment triangle is used inconsistently in practice for both implement triangles (on the attachment) and quick-release triangles (attached to the tractor).
The dimensions of quick coupling triangles are standardized by the ISO standard 11001-2. Depending on the size ( three-point category) and design, the triangles have different weights, but are usually easy to lift and assemble by one person.
The further development is the GDS triangle, in which the hydraulic system and PTO shaft can also be automatically coupled.
history
The “Weiste triangle” was patented in 1964 by its developer, the German Helmut Weiste, and successfully brought onto the market by the Soest- based family company Weiste under the brand name “Accord”. A triangle symbol then became the trademark (logo) of Weiste Accord . The agricultural machinery company later became famous for the development and production of pneumatic seed drills . In 1996 it was taken over by the Norwegian Kverneland Group , which continues to use the Accord brand name for sowing and fertilizing machines. Since Weiste Accord used a strong red for all devices by default, quick- release triangles are traditionally produced in a red color by other manufacturers to this day, although not necessarily.
Before the introduction of the Weiste triangle, the exact coupling of heavy implements to the lower links of the three-point hydraulic system of tractors was difficult and time-consuming, especially on uneven terrain. If no helper was available, the driver sometimes had to get in and out of the vehicle several times to adjust the lower links, and to drive back and forth and to handle tools, even when coupling to the upper link. In addition, the coupling process, during which the driver or a helper frequently stood between the tractor and the attachment, was prone to accidents. Ease of use, time savings and increased security are the main advantages of using quick-release triangles. In addition, several devices can be coupled together to form combinations. Technically unfavorable, however, especially with limit loads, the increased attachment length and the resulting shifted center of gravity away from the tractor can have an effect.
Since the end of the 20th century, new tractors have mostly been equipped with rear hydraulics that have self-locking hooks ("quick couplers") on the lower links as well as better lower link stabilizers, which enables quick and safe coupling as well as quick- release triangles . These have therefore become largely unnecessary and are only rarely found in the rear. However, they are still used regularly in front attachment today, at the beginning of the 21st century. This is due, among other things, to the fact that, unlike in the rear, the tractor driver's view of the attachment (via the bonnet) is restricted when it is mounted at the front. The advantages of using the triangle are more evident here. Many front-mounted devices are also factory-fitted with a device triangle as a suitable suspension device.
Coupling process
Before using the quick coupling triangle, it is first attached to the front or rear of the tractor to the two lower links and to the upper link of the three-point hydraulic system ("power lift", "hoist"). It can remain unchanged there as long as no devices are to be directly attached without a quick coupling triangle.
To couple an upright attachment, the tractor hoist is lowered with the quick coupling triangle and moved in as straight a line as possible (at a straight angle , 180 °) to the implement triangle. Then the tip of the quick coupling triangle is placed anywhere from below in the U-frame of the device triangle. During the subsequent lifting by actuating the three-point hydraulic system, the quick coupling triangle slides into the correct position in the implement triangle. When the coupling latching position is reached, the connection between the two triangular frames is automatically closed by a locking hook positioned slightly below the tip. The device is now coupled and can also be raised completely. The lock can also be secured against unintentional uncoupling with a bolt or spring pin .
After unlocking and releasing the safety connection, uncoupling takes place just as easily by lowering the attachment to the ground ("put it down") and then hydraulically pressing down or lowering the hoist, whereby the quick coupling triangle slides out of the implement triangle again.
Individual evidence
- ↑ a b c Helmut Weiste: Weiste Accord - triangle. 2004, accessed June 20, 2010 .
- ↑ a b Helmut Weiste: Weiste Accord - History. (No longer available online.) 2004, formerly in the original ; Retrieved June 20, 2010 . ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ a b c DLG test report 5514F: tractor triangle S2. (PDF; 551 kB) German Agricultural Society , August 2005, accessed on June 20, 2010 .
- ↑ ISO 11001-2: 1993 Agricultural wheeled tractors and implements - Three-point hitch couplers - Part 2: A-frame coupler
- ↑ a b Accord - pioneer in sowing and fertilizing technology. (No longer available online.) Www.kverneland.at, formerly in the original ; Retrieved June 20, 2010 . ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
Web links
- [1] ( Flash animation of the coupling and uncoupling process)
- Gangl Docking Systems (GDS GmbH) website