3 Point Hitch Attachments
Chances are if you own a tractor, it is equipped with a three point hitch. This Website is dedicated to explaining what exactly a three point hitch is, describe the different components, and then introduce you to a wide variety of attachments that will fit on a 3pt. hitch.
The three point hitch commonly refers to the way implements are attached to an agricultural tractor. In engineering terms, the 3 pt attachment is the simplest and most stable way to join 2 structures.
An implement can either be hooked on to a tractor hitch, or pulled and connected to the hitches. The 3 points on a hitch resemble a triangle, or the letter A. Its utility and simplicity has made it an industry standard for connecting and powering pull behind attachments for tractors.
Three Point Hitch Components
The 3pt. hitch is made up of several components working together, including the tractor's hydraulic system, the lifting arms, attaching points, and stabilizers. Each hitch has attachment holes for attaching implements, and the implement has posts that fit through the holes. The implement is secured by placing a pin on the ends of the posts.
A 3pt hitch is composed of 2 outer hitch lifting arms and a center top link. The 2 outer hitch arms provide lifting, lowering, and can be adjusted to tilt an attachment, such as a plow. Both hitch lifting arms are powered by the tractor's own hydraulic system. The hydraulic system is controlled by the operator, and usually a variety of settings are available. The lift arms extend rearward, and are the pull-point for the implement.
The center top link is movable, but usually not powered by a tractor's hydraulic system. This point of attachment is the third mounting point, and it also extends rearward from a top middle position at the rear of the tractor. Comparatively very little rearward force is applied from the top link unless the implement becomes bound up or twisted in some way. The top link often has a manual adjustment to achieve an optimum angle of attachment between the tractor and the implement.
The primary benefit of the 3-point hitch system is to transfer weight and stress of an implement to the rear wheels of a tractor. Larger implements require a corresponding larger-sized tractor with 3-point hitch specifications grouped in 5 different categories.
See Diagram of Components Below
There are 5 different hitch sizes, called categories. The higher category hitches have sturdier lift arms and larger connector pins. There is some flexibility in the tractor hp at which one category hitch ends and the next begins.
As an example, the Category I 3-point hitch is based on standards requiring that the pin sizes on the implement and corresponding lift-arm holes be 7/8" (.88-.89). The top link uses a 3/4" (.76-.77) pin and hole. The distance from the tail of the PTO shaft to the lift arm ends is approximately 14 inches. The minimum spread between the lower lift arms will be about 26-27 inches, the maximum spread is normally out to 33 inches or more.
|Type||Top Link Size||Lift Arm Size||Lift Arm Spacing||Tractor Drawbar Horsepower|
|0||5/8 Inch||5/8 Inch||20 Inches||Less Than 20|
|I||3/4 Inch||7/8 Inch||26 Inches||Less Than 45|
|II||1 Inch||7/8 Inch||32 Inches||40 to 100|
|III||1 1/4 Inch||1 7/16 Inch||38 Inches||80 to 225|
|IV||1 3/4 Inch||2 Inch||46 Inches||180 to 400|
History of The Three Point Hitch
Harry Ferguson patented the 3-point 'linkage', also called the "Ferguson System", for agricultural tractors in Britain in 1926. It enabled the operator to simply back up to the implement, connect, and lift. His credit is not for the invention of the device, but in the realization of the significance of having a rigid attachment of a plow to the tractor. Ferguson developed a number of improvements to this device, such as the hydraulic lift, which made this system desirable to the point of using it on commonly sold tractors, starting with the Ford 9N.
Prior the 1960s, each manufacturer used their own hitching systems for attaching implements to their tractors. A common example was the 2-point hitch system which was only effective with a few implements. At the time, farmers had to purchase the same brand implements as their tractor to be able to correctly hook up the implement. When farmers needed to use a different brand implement, ill-fitting and unsafe adaptor kits often had to be installed.
In the 1960s, tractor and implement manufacturers eventually agreed on the 3-point hitch as the standard system to hitch implements to tractors. As patents on technology expired, the manufacturers were able to modify and refine the system. Presently, almost all manufacturers have adopted some standardized form of the modern 3-point hitch system. Many companies also offer safe adaptor kits for conversion from non-standard hitch systems to the 3-point hitch system.
Typs of 3 Point Hitch Attachments
There are many types of 3-point hitch implements that can be attached to a tractor using the three-point hitch system. Often, industry develops new implements designed to handle even the most trivial tasks, helping save time and manual labor in farming, construction, grading, and landscaping.
We may classify these implements in 3 major groups: non-powered, power take off (PTO)-powered, and hydraulic-powered implements. Certain implements may even use a combination of PTO and hydraulic power to perform their task. Following are examples of common attachments under these groups.
PTOs & Safety
A power take-off (PTO) is a splined driveshaft, usually on a tractor or truck, that can be used to provide power to an attachment or separate machine. It is designed to be easily connected and disconnected. A PTO allows implements to draw energy from a tractor's engine. PTOs and associated shafts and universal joints are a common cause of accidents, injuries, and death in farming and industry. A great deal of tractor related fatalities in the USA involve PTOs. When a piece of clothing touches a spinning PTO or joint it can be pulled around, and the person wearing it can also be pulled around the shaft, often resulting in loss of limbs or death. Some implements use plastic guards to try to keep a person from becoming entangled in a PTO shaft, but even with guards caution around spinning PTO shafts is imperative.