Patent Application
20160115999
The present disclosure relates to a connection mechanism for connecting a tractor PTO to an implement propeller shaft.
Tractors and utility vehicles used for agricultural work may be coupled to implements which have a propeller shaft which must be connected to the tractor PTO shaft. Implements are not utilized full time with a tractor, so it is desirable that a coupling mechanism allow quick, easy removal and reinstallation of the implement. A tractor PTO shaft may be connected and secured to a propeller shaft on the implement using PTO coupling members. PTO shafts take time to hook up and can be difficult because of their size and location. An automatic connection mechanism is needed for an implement that can be quickly and easily connected and disconnected under a tractor. A PTO coupling is needed that can reduce the difficulty of securing a tractor PTO to a propeller shaft on the implement.
According to an aspect of the present disclosure, a connection mechanism is provided for connecting an implement to a tractor PTO. The connection mechanism includes a PTO adapter shaft, a PTO stub shaft, a coupler frame, an adapter holder and a resilient member. The PTO adapter shaft is mounted to the implement and has internal adapter splines. The PTO stub shaft has external stub splines for meshing engagement with the adapter splines. The coupler frame is adapted to be attached to the implement. The adapter holder is mounted to the coupler frame and is movable with respect to the coupler frame. The adapter holder receives and rotatably supports the PTO adapter shaft. The resilient member is coupled between the coupler frame and the adapter holder, and is biased to urge the adapter holder and the PTO adapter shaft towards the PTO stub shaft.
The adapter shaft has a first bore forming the adapter splines and has a second bore extending from the first bore to an end wall which faces towards the first bore. The first bore has a larger diameter and the second bore has a smaller diameter. The stub shaft has a first portion forming the stub splines externally thereon, and has a second portion extending away from the first portion. The first portion has a larger diameter and the second portion has a smaller diameter. The second portion has an outer end with a chamfer, and has first and second journals formed thereon. The first journal is spaced axially apart from the second journal. The first and second journals are slidably received by the second bore.
The adapter holder pivotally and slidably engages a portion of the coupler frame. The adapter holder has a smaller diameter hollow main body and has a larger diameter hollow front flange which forms an annular wall which engages the resilient member. The resilient member is mounted around the main body of the adapter holder.
With this connection mechanism, the operator can leave the adaptor shaft connected to the standard PTO shaft of the implement. The adapter shaft can easily be connected to the stub shaft that replaces the standard PTO shaft on the tractor.
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A hollow cylindrical holder 90 is received by the opening 88 and slidably and pivotally engages the retainer plate 86. Holder 90 includes a smaller diameter main body 92 and a larger diameter front flange 94 which forms a rearwardly facing annular wall 96. The adapter shaft 20 is received by the holder 90 and supported within the holder 90 by annular bearing 98. Bearing 98 is held between wall 40 and a snap ring 100. A snap ring 102 retains the bearing 98 within the holder 90. Thus, the adapter shaft 20 is fixed axially with respect to the holder 90, but it can rotate within the holder 90. Because opening 88 is slightly smaller than opening 84, the holder 90 and the adapter shaft 20 are allowed to move radially with respect to the coupler housing 18 to aid in self-aligning the PTO adapter shaft 20 with respect to the PTO stub shaft 14. As a result, the adapter holder 90 and the PTO adapter shaft 20 are pivotal with respect to the housing 18 in directions perpendicular with respect to an axis of the PTO adapter shaft 20.
An annular resilient member 104, such as a stack of annular Belleville springs, is mounted around the main body 92 between wall 96 and center leg 82. Resilient member 104 is biased to urge the holder 90 and the adapter shaft 20 towards the PTO stub shaft 14.
To use this connection mechanism, the standard PTO shaft (not shown) on a tractor is replaced with by the PTO stub shaft 14. The two tightly toleranced journals 66, 68 and generous chamfer 64 and surfaces 27 and 29 allow the adapter shaft 20 to slide on the journals and align the adaptor shaft 20 with the stub shaft 14. The adaptor shaft 20 has a bore 26 with a tight tolerance and is mounted in the frame 18 on an implement socket used with a production pick up hitch 10. The pickup hitch 10 pulls in the adapter shaft 20 towards the tractor stub shaft 14. The adapter shaft 20 is allowed to float in the frame 18 so that it can be coaxially aligned with the stub shaft 14. The final step is to engage the splines 61 on the stub shaft 14 with the splines 34 in the adaptor shaft 20. The splines have tapered ends to prevent a tooth butting condition. Since the two shafts are concentric due to the journals 66, 68, indexing the splines is very easy. If the splines were not to index, the Belleville springs 104 will compress to prevent damage. Once rotation has started, the springs 104 will force the adapter shaft 20 onto the stub shaft 14.
While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. It will be noted that alternative embodiments of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the present invention as defined by the appended claims.
