How to Identify an Agricultural PTO Driveline
An agricultural power take-off (PTO) driveline is a drive-shaft type device that connects a tractor to the farming implement it needs to operate. The connection provided by the driveline allows the implement to draw power directly from the tractor’s engine. Much like fluid hydraulic mechanisms, PTO drivelines will eventually break down from the rigors of daily farming projects and need to be replaced or repaired. When it is necessary to replace or repair a PTO driveline, it is important to choose the correct components applicable to the specific equipment in use. In order to choose the replacements correctly, you will need to know the answers to these four simple questions about your particular driveline:
· What kind of equipment will the driveline be used on? (Identify by application)
· What are the individual driveline components?
· Is the driveline North American or Metric?
· What series is the driveline?
What kind of equipment will the driveline be used for? (Identify by application)
If you know which piece of equipment the driveline will be used for and want to replace the complete driveline, then identification is a quick two-step process:
Simply select the category of equipment and then choose the tube shape (see pictures below) and length for the driveline you want to replace.
If you need a replacement for a component of the driveline refer to the following identification process.
What are the Individual Driveline Components?
1.Tractor Yoke- The PTO assembly begins with this type of yoke. It is connected to the tractor, and used to attach the driveline. There are two main types of tractor yokes. The first type is a Spring-Lock, which uses a spring-loaded collar to attach and release the yoke. The second type is a Quick Disconnect, which uses a push-pin mechanism for connectivity.
The tractor yoke can also be designated as 6-spline, 20-spline, or 21-spline, representing how it matches to the connection on the tractor. This can be identified by counting the notches on the inside of the yoke collar.
2. Cross and Bearing Kit- This is a u-joint that connects the yokes in the PTO assembly. The cross and bearing kit will either have a snap ring located internally in the bushing or located externally, meaning it can be found in the ears of the yoke.
3. Shaft Yoke- Using a cross and bearing kit, this connects the tractor yoke to the driveline shaft.
4. Shaft- The shaft is the metal rod at the core of the driveline providing its length and connecting the yoke attachments.
5. Tube- The shaft runs inside this metal cylinder adding reinforcement to the driveline
6. Tube Yoke- Attached to the end of the tube, this yoke connects the driveline to the implement using a second cross and bearing kit.
7. Implement Yoke- This connects the driveline to the machine or device being maneuvered by the tractor.
8. Guard- A hard plastic covering is placed around the driveline to prevent damage during operation.
Is the Driveline North American or Metric?
The simplest way to figure out whether a PTO is North American or metric is to determine the shape of the tubing and shafting. A PTO is domestic if the tubing/shafting is square, rectangle, hex or splined. If the tubing/shafting is bell, lemon or star-shaped, then it is metric. There are two types of metric drivelines: German style (Walterscheid brand) and Italian style (Bondioli & Pavesi). The German style shafting/tubing has lemon and star profiles while the Italian has a bell-shaped design.
What Series is the Driveline?
An accurate way to determine which series of PTO you have is to take two measurements of the cross and bearing kit on the tractor-end of the driveline. Using calipers, measure the outside diameters of the u-joint caps, which would be the same as measuring the inside holes of the yoke ears.
Second measure the u-joint end-to-end both ways. Match these measurements using a cross and bearing identification chart and the remaining PTO components needed or the complete driveline required can be determined with ease.
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