Background of the Invention
The present invention pertains to a cam operated locking device for interlocking two relatively movable elements, for example a vehicle seat and its support.
In certain industrial equipment, for example, an over-highway truck, it is desired to isolate movement of the operator's seat. The seat is adjustably mounted on a frame, which is slidably carried on a support or riser box to isolate the seat and operator from jarring movement by the machinery or vehicle. A locking device is used to lock the seat frame in position when the operator desires to prevent the seat from sliding on its support and thus stopping the isolating function. Present locking devices are relatively complex and costly.
Prior art patents reveal various forms of chair or seat locking arrangements, but none teaches or suggests the invention disclosed and claimed herein. Duly U.S. Pat. No. 4,165,854 discloses a locking device having a cam operator for moving a pin and thereby engaging and disengaging a locking pin from a socket. The pin is held in contact with the cam operator by means of a spring. A similar mechanism is shown in Wehner U.S. Pat. No. 4,113,221. As will be shown more particularly hereianfter, the present invention is not taught or suggested by these references.
An object of the present invention is to provide for a vehicle seat (e.g., an off-highway truck seat) an improved cam operated locking device that can be biased to a locking position and retained in an unlocked position by cam means.
Another object of the present invention is to provide an improved cam operated locking device for a seat that carries a frame having a recess therein, said locking device including a U-bar housing having a lever rod rotatably and reciprocably carried in said U-bar housing and adapted to engage with, and be disengaged from, said recess, a pin on said lever rod engaging cam means on said U-bar housing, spring means biasing the lever rod toward said recess, said cam means cooperating with said pin to permit said lever rod to be biased into said recess when said lever rod is in a first position and to lock said lever rod away from said recess when said lever rod is in a second position. Other objects and advantages of the present invention will be made more apparant hereianfter.
Brief Description of the Drawing
There is illustrated in the attached drawing a presently preferred embodiment of the present invention wherein like numerals in the various views refer to like elements and wherein;
FIG. 1 is a right front perspective view of a seat mounted on a riser box in a vehicle and illustrating the cam operated locking device of the present invention;
FIG. 2 is a detailed front view of the cam operated locking device illustrating the lever rod in a recess in the seat frame so as to lock the seat against movement relative to the riser box;
FIG. 3 is a bottom view of the cam operated locking device; and
FIG. 4 is a right front perspective view of the cam operated locking device illustrated from the bottom.
Detailed Description of the Present Invention
Referring to FIG. 1 there is illustrated a seat 10 which is adapted to be slidably mounted upon a riser box 12 that is secured to a frame, (e.g., the floor of the vehicle) by suitable fastening means, (e.g., bolts extending through holes 13 in the bottom of the riser box into the vehicle floor). The seat 10 includes an isolator frame 17 depending therefrom for permitting sliding movement of the seat with respect to the riser box 12. The present invention concerns a cam operating locking mechanism 14 which secures the isolator frame 17 to the riser box 12 and is separate from the normal mechanism for securing the seat 10 to the slide rails 24.
The isolator frame 17 for the seat 10 includes depending side members 16 and 18 which are interconnected by cross members 20 and 22. Slide rails 24 permit longitudinal sliding of the seat 10 with respect to the frame 17. The isolator frame 17 is longitudinally slidable with respect to the riser box 12. The cam operating locking device 14 is operative to secure the riser box 12 to the frame 17 for the seat 10 to prevent sliding of the seat on the riser box 12, or alternatively, to permit the cam operated locking device 14 to be locked out so as to permit sliding motion of the seat isolator frame 17 with respect to the riser box or support 12.
The structure and operation of the cam operated locking device 14 will be better understood by reference to FIGS. 2, 3 and 4. The isolator frame 17 includes a cross member 20 that is provided centrally with an insert 26 having a recess 28 therein for receiving the end of the lever rod 30 of the cam operated locking device 14.
The cam operated locking device 14 is secured to bracket means 32 which forms part of the riser box 12. The U-bar housing 34 of the cam operated locking device is secured to the bracket 32. The lever rod 30 is both reciprocably and rotatably secured within the U-bar housing 34. Further, the U-bar housing 34 is constructed and arranged to position the lever rod 30 axially with respect to the recess or opening 28. Secured transversely of the lever rod 30 within the U-bar housing 34 is a pin 36. The pin 36 may be hollow as shown, or alternatively, the pin 36 may be solid. A coil spring 38 is disposed on the lever rod 30 and is mounted between the bight 33 of the U-bar housing 34 and the pin 36. The coil spring 38 functions to bias the lever rod 30 into the recess 28 of the frame cross member 20. The end of the lever rod 30 is formed as a handle 40 to facilitate rotation of the lever rod 30.
Cam means 42 are formed on the U-bar housing 34 for properly positioning the lever rod 30 with respect to the recess 28 as desired by the operator. The cam means 42 are defined on the wall means 44 which extend from the bottom of the bracket 32. The cam means 42 comprise a first cam surface 46 and a second cam surface 48. It will be understood that there is an opposed cam surface 46 and 48 on the opposite wall 45. In a preferred embodiment of the present invention, the cam surfaces 46 and 48 are essentially opposed diagonal, or opposed inclined, planar surfaces.
FIG. 2 shows the position of the cam operated locking device 14 with the end of the lever rod 30 in engagement within the recess 28 in the insert member 26. In this position, the isolator frame 17 and the seat 10 carried thereby are locked with respect to the riser box 12. The pin 36 which extends transversely of the lever rod 30 is positioned against the opposed cam surfaces 48 on the wall means 44 and 45. Spring 38 operates between the bight 33 of the U-bar housing 44 and the pin 36 to bias the lever rod 30 upwardly, as viewed in FIG. 2, into engagement with the recess 28.
When it is desired to release the end of the lever rod 30 from the recess 28, the handle 40 is rotated so as to move the pin 36 downwardly on the inclined surfaces 48. Upon such rotation, the end of the lever rod 30 is disengaged from the recess 28 and the isolator frame 17 can be moved. If it is desired to lock the lever rod 30 out of engagement with the recess 28, the pin 36 is moved over center from cam surface 48 onto the cam surface 46. The spring 38 is compressed and the pin 36 will be held on cam surface 46 between the opposed surface 46 and the U-bar housing 34 in order to hold the end of the lever rod 30 out of engagement with the recess 28.
It will be understood that when the pin 36 is moved from cam surface 46 onto cam surface 48, the spring 38 will bias the pin 36 and the lever rod 30 upwardly until the upper end of lever rod 30 is seated in the recess.
A person skilled in the art will appreciate that the seat 10 can be separately adjusted for tilt, as well as fore and aft positioning with respect to the frame 17. Such adjustments are known in the art and form no part of the present invention.
There has been provided by the present invention a simplified, cam operated locking device for selectively locking an off-road vehicle seat (e.g., a seat having an isolator frame movable with respect to a riser box). The cam operated locking device of this invention comprises very few parts, is very easy to assemble and operate, and results in significantly less manufacturing costs and better reliability in use.
While I have shown a presently preferred embodiment of the present invention, it will be understood that the invention may be otherwise embodied within the scope of the following claims.