Background of the Invention
Clutch mechanisms find wide use in power drive trains and in other modern industrial mechanisms. Many of these clutches use hydraulic fluid and pressure to actuate or de-actuate the clutching mechanism. One such clutch which has met with considerable commercial success is described and claimed in U.S. Pat. No. 4,226,319 to Euler and Pear.
However, many vehicles and other mechanisms are not provided with sources of hydraulic power. Non-hydraulic, strictly mechanical clutches are required in these services.
It is accordingly the general object of the present invention to provide a clutch unit which is effective and powerful in operation, yet which does not require hydraulic fluid or hydraulic pressure for its operation.
Another object is to provide a non-hydraulic clutch unit which is compact in its overall dimensions, yet which effectively transfers large amounts of torque or mechanical energy without slipage.
Another object is to provide such a non-hydraulic clutch which is reliable and rugged in design and manufacture, yet which can be offered at a commercially attractive price.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. Throughout the drawings, like reference numerals refer to like parts.
Brief Description of the Drawings
FIG. 1 is an end elevational view of the novel clutch;
FIG. 2 is a side elevational view of the clutch;
FIG. 3 is a sectional view taken substantially in the planes of the lines 3--3 in FIG. 1; and showing the clutch in its shafts-disengaged condition;
FIG. 4 is a fragmentary sectional view similar to FIG. 3 but showing the clutch in its shafts-engaged condition; and
FIG. 5 is a sectional view taken substantially in the planes of line 5--5 in FIG. 2.
Detailed Description
While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to this embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
Turning more particularly to FIGS. 1-3, there is shown a clutch 10 embodying the present invention. It will be understood that this is a strictly mechanical clutch; that is, no hydraulic or other fluid power systems of any kind are required for its operation. The clutch illustrated includes a housing 11 which comprises generally opposed housing halves 12 and 13 connected to one another by any convenient arrangement such as a series of bolts 14. A first shaft member 17 is journaled in the housing 11, as by bearings 18, and a second or output shaft 19 is here carried at least partly inside the housing 11 in coaxial relationship with the firt shaft 17, as illustrated. A bearing 20 journals this second shaft 19 within the housing 11, and another bearing 21 is interposed between the shaft members 17 and 19 to permit the shafts 17, 19 to rotate freely with respect to one another. This first shaft 17 is provided with a series of female or internal splines 24, and the second shaft 19 is provided with male splines 25 to permit the shafts to be attached to other power train mechanisms such as speed reducers, prime movers, or the like (not shown).
Integral with the first shaft 17 is a cup member or element 30. The interior of this cup element 30 is provided with splines, and a series of first discs 32-35 extend radially inwardly from the shaft cup 30. The spline interconnection 31 permits the first discs 32-35 to rotate with the first shaft 17, and permits those discs limited axial motion over and within the cup 30.
Interleaved in the first discs 32-35 is a set of second discs 42-45. These second discs 42-45 are splined, as by spline connections 41, to the second shaft 19. The second discs 42-45 radiate outwardly from the shaft 19, and thus form a disc stack 47 with the first discs 32-35. It will be understood that when the disc stack 47 is axially compressed and the discs interengage as shown in FIG. 4, the first shaft 17 and its cup 30 are caused to rotate with the second shaft 19 in a shafts-engaged configuration.
To mechanically squeeze together the discs of the disc stack 47 and couple the shafts 17 and 19 in accordance with the invention, a collar cam structure 50 is provided. Here, this collar cam means 50 includes an axially fixed element 51 and an axially movable element 52. Facing cam surfaces 55, 56 together describe a series of substantially v-shaped grooves which act as ball ramps, as shown especially in FIGS. 3 and 4.
The position of the fixed element 51 can be adjusted in an axial direction along the shaft 19, because that fixed element 51 is connected, as by the spline connection 31, to a ring member 57, and the ring member 57 is attached, as by a threaded interconnection 58, to the cup element 30 of the firt shaft 17. The threaded attachment 58 has an axis substantially coincident with one or both of the main clutch shafts 17, 19, so as to permit the position of the collar cam fixed element 51 to be adjusted along the axis of the shaft. This thread arrangement permits clutch operation to be adjusted after assembly. It will be understood, of course, that the shafts 17, 19 and the interconnected cup 30 do not move axially during shaft rotation or clutch operation.
Interposed between the collar cam elements 51, 52 are a series of interconnector balls 60. When these balls 60 are moved radially outwardly from the position shown in FIG. 3 to that shown in FIG. 4, the collar cam element 52 is urged in a first direction (to the right, in the illustrations) away from the fixed cam element 51 so as to axially compress the discs of the disc stack 47. This disc stack compression and disc interengagement causes the shafts 17 and 19 to be interconnected for rotation with one another.
When, however, the ball elements 60 move from the position shown in FIG. 4 radially inwardly to the position shown in FIG. 3, the disc stack 47 is released and the shafts 17, 19 are permitted to rotate freely with respect to one another. Tension springs 62 connected between the first and second collar cam elements 51, 52 urge those elements to rotate or otherwise move so as to bring the cam surfaces 55, 56 back into registry with one another. This action permits other clutch parts to move or re-adjust themselves so as to provide running clearances within the clutch unit.
In carrying out the invention, uniform compressive loading of the disc stack 47 is encouraged. In the illustrated embodiment, this is provided by a spring disc or tinnerman washer 65 interposed between the cup element 30 and the disc stack 47. It will be understood, of course, that it is most convenient to locate this disc spring 65 at an end 67 of the disc stack 47 which is opposite that end 68 abutted by the movable cam element 52.
In furtherance of the invention, radially outward motion of the interconnector balls 60 is caused by a sleeve cam 70, which is here telescoped over the second shaft 19. As illustrated particularly in FIGS. 3 and 4, this sleeve cam 70 includes a conical ramp cam surface 72 which engages the interconnector balls 60 and forces them radially outwardly of the sleeve cam 70 between the fixed and movable collar cam elements 51, 52. The conical ramp cam surface 72 terminates in a detent 74 which operates to retain the interconnector balls 60 in positions such that the movable cam element 52 squeezes the disc stack 47 into a shafts-coupled condition, as illustrated in FIG. 4.
A yoke 76 is provided to move the sleeve cam 70 in its axial direction over the shaft 19 and consequently couple or uncouple the shafts. This yoke 76 does not rotate, but, as explained above, the sleeve cam 70 does turn when the clutch is in its shafts-coupled condition, FIG. 4. Consequently, a bearing 78 is provided to make a low-friction interconnection between the yoke 76 and the sleeve cam 70.
Axial motion of the yoke 76 is caused by the yoke arms 77, 78 and the pin interconnectors 79, 80 shown in FIG. 5. As illustrated there, the arms 77, 78 are formed integrally with a base 81, and that base 81 is affixed, as by a key 82, to a cross-shaft 83. The cross-shaft 83 extends outside the housing 11 and is secured to a lever 84. Thus, when the lever 84 is moved into the appropriate position, that lever motion is transferred to the yoke collar 76. The yoke collar 76 moves the sleeve cam 70 so as to force the interconnector balls 60 into positions to squeeze the disc stack 47 and couple the shafts 17, 19.