BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment of the invention, with reference to the attached drawings, in which:
FIG. 1 is a side elevational view of a conventional all-terrain vehicle;
FIG. 2 is a cross-sectional view of a conventional transmission mechanism of the all-terrain vehicle;
FIG. 3 is a cross-sectional view of a portion of a conventional engine of the all-terrain vehicle;
FIG. 4 is a cross-sectional view taken along line A-A of FIG. 3;
FIG. 5 is a perspective view of a conventional park-position mechanism for the all-terrain vehicle;
FIG. 6 is a cross-sectional view of a portion of an engine in accordance with the present invention;
FIG. 7 is a cross-sectional view taken along line B-B of FIG. 6;
FIG. 8 is a perspective view of a park-position mechanism in accordance with the present invention;
FIG. 9 is an exploded view of a park arm of the park-position mechanism of the present invention;
FIG. 10 is a side elevational view showing the park-position mechanism in a condition where a main shaft of the transmission is secured by the park-position mechanism;
FIG. 11 s a side elevational view showing the park-position mechanism in a condition where the main shaft of the transmission is released from the park-position mechanism; and
FIG. 12 is a side elevational view showing the park-position mechanism in a condition where the transmission is switched to a PARK position while the park-position mechanism does not correctly engage a park gear on the man shall
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following descriptions are of exemplary embodiments only, and ate not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.
With reference to the drawings and in particular to FIGS. 6-8, a park-position mechanism constructed in accordance with die present invention comprises a cam 522 arranged by a selector hub 521 that is mounted on a selector huh shaft 52 that constitutes partly a selector mechanism 5 of for example an all-terrain vehicle. A park gear 531 is mounted on a main shaft 53 of the selector mechanism 5 and corresponding in position to the cam 522. A park arm 6 is arranged between the earn 522 and the park gear 531.
Also referring to FIG. 9, the park arm 6 forms a centrally-located holed base 61 that is rotates and fits over a stud 63 that rotates and supports the park arm 6 in a crankshaft case 7 and to allow the park arm 6 to rock about the stud 63 with opposite ends displaced upward and downward. A torsion spring 64 is arranged between the holed base 61 of the park arm 6 and the crankshaft case 7 with opposite ends of the torsion spring 64 attached to the park arm 6 and the crankshaft case 7. A driven section 61 and an engaging section 62 are respectively formed on opposite ends of the park arm 6. The driven section 61 comprises a cylindrical extension through which a guide hole 611 is defined. A resilient member 612, such as a helical spring, is mounted to a front side of the guide hole 611 and encompasses a guide rod 613, which also extends through the guide hole 611. The guide rod 613 has a front end forming an expanded stop 6131 and an opposite rear end forming a circumferential groove 6132. A stop ring 614 is fit on the rear end portion of the guide rod 613 and is retained on the guide rod 613 by a clip 615 that is received in the circumferential groove 6132 of the guide rod 613. The expanded stop 6131 on the front end of fee guide rod 613 has an outside diameter greater than diameters of the resilient member 612 and the guide hole 611 and serves to retain the resilient member 612 in position at the front side, while the resilient member 612 is retained by stop ring 614 at fee rear side. With such an arrangement, the guide rod 613 is allowed to axially move with respect to the guide hole 611 with the expanded stop 6131 engaging the cam 522. The engaging section 62 of fee park arm 6 comprises a bent end forming a projection 621 feat is normally located above the park gear 53 and is selectively moved toward and engages the park gear 53 when the selector mechanism 5 is switched to the PARK position.
Referring now to FIGS. 7,8, and 10, when the operation lever is switched to the “P” position (not shown in the drawings), the selector lever 51 of the selector mechanism 5 moves the gear 511 mounted thereto to cause displacement of the selector hub 521 whereby the cam 522 arranged next to the selector hub 521 forces the expanded stop end 6131 of the guide rod 613 of the driven section 61 of the park arm 6 upward, and the force induced by the cam 522 is transmitted by die stop end 6131 of the guide rod 613 to the resilient member 611, which in turn applies the force to driven section 61 of the park arm 6 to cause the driven section 61 to move upward. The upward movement of he driven section 61 of the park arm 6 makes the engaging section 62 of the park arm 6 simultaneously moving downward, with the torsion spring 64 compressed by the rotation of the park arm 6, to have the projection 621 of the engaging section 62 of the park arm 6 to engage a deddendum trough 531a between adjacent teeth of the park gear 531 so as to fix the main shaft 53, thereby securing the main shaft 53 and the rear wheels and making the all-terrain vehicle in a stable parking condition.
On the contrary, when the operation lever is off the “P” position, the cam 522 next to the selector hub 521 no long drives the expanded stop end 6131 of the guide rod 613 of the driven section 61 of the park arm 6, and the force induced by the cam 522 on the guide rod 613 is released, and in response thereto, the torsion spring 64 springs back and induces a torque on the park arm 6 to move the engaging section 62 away from the trough 531a of the park gear 531 thereby releasing the main shaft 53. The main shaft 53 is now allowed to rotate again.
Also referring to FIGS. 11 and 12, during the switching to the PARK position, in case that the projection 621 of the engaging section 62 does not smoothly move into the trough 531a of the park gear 53 and is instead blocked by a top face 531b of any one tooth of the park gear 53, although the cam 522 continuously applies a force to move the guide rod 613, such a force is absorbed by the compression of the resilient member 612 with the guide rod 613 moved with respect to the driven section 61 but the driven section 61 of the park arm 6 remaining standstill. Thus, the driving force from the cam 522 is absorbed by the compression of the resilient member 612 and the relative movement of the guide rod 613 with respect to the drivers section 61. The compression of the resilient member 612 also induces a preloading of the resilient member 612, which, after the main shaft 53 makes a further rotation to align the trough 531a with the projection 621, effectively drives the projection 621 into the trough 531a to effect securing of the main shaft 53 and achieving switching to the PARK position.
The feature of the present invention is the guide rod 613 that is movably mounted to the driven section 61 of the park arm 6 and the resilient member 612 arranged between the driven section 61 and the guide rod 613, which are used to absorb the driving force acting on the driven section 61 by the cam 522 whereby when it happens that the projection 621 of the engaging section 62 of the park arm 6 is blocked by the top face 531b of a tooth of the park gear 531, the park aim 6 may not be damaged by the driving three form the cam 522 and the position switching operation is made even smoother.
In accordance with the present invention, the resilient member 612 and the guide rod 613, which function to absorb the driving force of the cam 522, are arranged on the driven section 61, which makes fee assembling of the park arm easy and simplifies the assembling process.
It will be understood that each of the elements described above, or two or more together may also fed a useful application in other types of methods differing from the type described above.
While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to fee details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.
Patent Application
20080073172
