Patent Application
20060032722
The invention herein resides in the art of power transmission devices and, more particularly, to clutch systems interposed between a power source and load to selectively transfer the power from the source to the load. More particularly, the invention relates to a hydraulically actuated power take-off clutch system, and more specifically, to such a hydraulic clutch system adapted for replacement of a manually actuated over-center clutch within the housing and envelope of the manually actuated clutch.
Dry over-center power take-off clutches are in common use from the largest engine driven industrial type employed with shredders and grinders, to simpler smaller machines of all types and natures. Such PTO's have been fraught with problems incident to the utilization of pilot bearings, necessary adjustments, and operator abuse.
A multitude of such over-center power take-off clutches continue in use with the inherent problems just described. Many such clutches comprise commercial embodiments of the clutch set forth in prior U.S. Pat. No. 5,400,862. A large number of those are maintained in housings conforming to SAE J621d, defining the envelope in which the clutch operating mechanism is received. Many such clutches further conform to SAE J620 as to the flywheel ring connector, and to SAE J617c as to the flywheel housing both pattern.
There is a need in the art for a dry hydraulic power take-off clutch that can be readily retrofitted into the envelope of the former mechanical over-center dry clutches within housings having dimensions that conform to SAE J621d, and adapted to mate with a flywheel and flywheel housing conforming to SAE J620 and SAE J617c, respectively.
In light of the foregoing, it is the first aspect of the invention to provide a hydraulic dry power take-off clutch PTO which can be readily retrofitted or substituted for corresponding mechanically actuated dry over-center power take-off clutch.
Another aspect of the invention is the provision of a retrofitted hydraulic power take-off clutch that comprises a rotary union in operative engagement with a clutch disk assembly, the rotary union providing means for transferring pressurized hydraulic fluid from an external source to the clutch disk assembly.
Another aspect of the invention is the provision of a retrofit hydraulic power take-off clutch that eliminates the need for frequent adjustments.
Still a further aspect of the invention is the provision of a retrofit hydraulic power take-off clutch that is less susceptible to operator abuse than the prior dry over-center power take-off clutches.
Yet a further aspect of the invention is the provision of a retrofit hydraulic power take-off clutch that can be configured in various sizes and arrangements to fit a large variety of envelopes of prior mechanical clutches.
The foregoing and other aspects of the invention which will become apparent as the detailed description proceeds are achieved by a kit for converting a manually actuated dry over-center power take-off clutch to a hydraulically actuated one, comprising: an input hub securedly received upon a shaft; an end plate secured to said input hub; a drive flange adapted for securement to a flywheel of a power source; a hydraulically actuated clutch disk assembly received upon a first end of said input hub and in interconnection with the drive flange; and a rotary union received upon an opposite second end of said input hub.
Additional aspects of the invention are achieved by a hydraulic power take-off clutch, comprising: a housing conforming to the envelope of a housing configured according to SAE J621d, said envelope defining an envelope, said envelope receiving: an input hub securedly received upon a shaft; an end plate secured to said input hub; a drive flange adapted for securement to a flywheel of a power source; a hydraulically actuated clutch disk assembly received upon a first end of said input hub and in interconnection with said drive flange; and a rotary union received upon an opposite second end of said input hub.
For a complete understanding of the objects, techniques and structure of the invention, reference should be made to the following detailed description and accompanying drawings wherein:
Referring now to the drawings and more particularly
The clutch assembly 10 includes a bell housing 12 for maintaining the clutch mechanism therein. The bell housing 12 is adapted to be mounted to a power source such as an engine or the like and, in that regard, is provided with standard housing dimensions and mounting bolt spacings corresponding to SAE J621d and SAE J617c.
The clutch 10 includes a drive flange or ring 14 adapted to be mounted upon a flywheel or other power output means of an appropriate power source. Again, the drive flange or ring conforms to a particular SAE standard, such as SAE J620.
Mounted within the bell housing 12 are friction plates or disks 16 and separator plates or disks 18. In the embodiment shown, the friction disks 16 are splined to the drive flange or ring 14, while the separator disks 18 are keyed to the output hub 20. The output hub 20 is keyed to the output shaft 22.
A pressure plate 24 is maintained in juxtaposition to the stack of interleaved disks 16, 18. An over-center actuator 26 is manually controlled by a lever arm 28 to urge the pressure plate 24 into the stack of interleaved disks 16, 18 to cause frictional engagement therebetween and transfer rotational power or torque from the drive flange or ring 14 to the output hub 20 and output shaft 22. A throw out bearing and related mechanism 30 is provided with the mechanical clutch 10 in standard fashion.
Clutch 10, just described, is fraught with problems discussed above regarding pilot bearings, adjustments, and operator abuse. The elimination of such problems is readily achieved by the substitution of a hydraulically actuated power take-off clutch within the same envelope as that receiving the assembly 16-32 as just described.
With reference now to
The clutch disk assembly 56 includes a piston 58 operative to axially engage friction disks 60 and separator disks 62, the former being splined to the drive flange or ring 44, and the latter keyed to the input hub 48. While the assembly is shown with three friction disks 60 and two separator disks 62, various sizes and diameters of disks 60, 62 may be employed, dependent upon the desired output inertia or torque and/or and the envelope to be filled.
A spring biased shoulder bolt 64 urges a first separator disk 62 from the piston 58. A second spring biased shoulder bolt 66 urges a second separator disk 62 from the first one. Accordingly, a desired and necessary built-in clearance is maintained between the friction and separator disks at times of disengagement. This also precludes the likelihood of inadvertent engagement when the assembly 40 is set on a incline or the like.
A back plate 68 is maintained upon the input hub 48 with an annular space between the back plate 68 and piston 58 defining an annular piston head cavity 70 for the pressure head to be urged against the piston 58 as provided through the rotary union 54.
With further reference to
In the preferred embodiment of the invention, the inboard gland ring 78a is of a larger diameter than the outboard gland ring 78b to provide a hydraulic piston effect on the rotary union collar 72. This tends to load the outboard bearing 84b against the keeper or stop 85 for stabilization against the inherent vibration characteristic of many machines.
As further shown in
A keeper ring 90 is received by the input hub 48 to fixedly restrain the back plate 68 thereupon to preclude movement thereof when pressurized hydraulic fluid is introduced into the piston head cavity 70.
As shown in
As shown in
With reference to
It should now be readily appreciated that an SAE standard bell housing 12 and drive ring or flange 14 of previously known mechanical dry over-center take-off clutch assemblies may be readily retrofitted by substituting the over-center actuator and associated clutch of the prior art with a hydraulically actuated clutch assembly within the same envelope and adapted for interconnection with an SAE standard flywheel and flywheel housing. By implementing a rotary union and hydraulic clutch assembly upon a single shaft, and by providing a hydraulic fluid conduit within the input hub 48 between the annular input cavity 80 and annular piston head cavity 70, where prior art over-center manual clutches were previously employed, such substitution eliminates the deficiencies of the prior art with respect to adjustments, pilot bearings, and operator abuse. Moreover, the input hub and shaft, with associated rotary union conduits, may be integrally formed, reducing cost and increasing integrity.
Thus it can be seen that the objects of the invention have been satisfied by the structure presented above. While in accordance with the patent statutes only the best mode and preferred embodiment of the invention has been presented and described in detail, it will be appreciated that the invention is not limited thereto or thereby. Accordingly, for an appreciation of the true scope and breadth of the invention reference should be made to the following claims.
