Hydraulic door opening/closing and locking/unlocking apparatus

#This invention relates to hydraulically operated doors, and in particular to hydraulically operated tailgate doors for vehicles, such as trucks having a bed which can be raised for dumping material after the tailgate door is opened.

#Many trucks having raised beds include a manually releasable or powered latch for the tailgate door and hydraulic cylinders for pivotally raising the door to an open position. After dumping, the door is then pivotally lowered to a closed position and manually locked. In such pivoting tailgate doors, since the doors are hinged at the top, generally the door seal is much better at the top of the door then at the bottom where it is latched. Often, shims are used at the door hinge mounting positions to move the top of the door away from the frame in an attempt to equalize the seal around the door perimeter. Shim adjustment, however, is very time consuming, and at best, results in a degradation of the tight seal at the top of the door while providing a moderate seal around the entire door perimeter.

#Therefore, it is desired to provide a hydraulically operated tailgate door which is pivotally hinged and yet can provide a tight seal around the entire door perimeter. Also, it is desired to provide a hydraulically operated tailgate door without requiring manual locking and unlocking of the door.

#The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the several figures and in which:

#FIG. 1 is a front elevational view, symmetrical about the center line, illustrating a vehicle door frame and a hydraulically operated door which can be unlocked, raised, lowered, and locked with the same hydraulic means;

#FIG. 2 is a side elevational view fragmented to illustrate the vehicle door frame, and hydraulic operating apparatus for a hydraulically operated tailgate door in accordance with the principles of the present invention; and

#Referrig now to the drawings, there is illustrated a preferred embodiment of the present invention in which a tailgate door 1 is mounted by means of a hinge bracket 2 to a door frame opening at the rear of a vehicle such as a truck 30. It is understood that in connection with FIG. 1, only one half of the vehicle and the tailgate door is illustrated, the right hand portion being symmetrical about the indicated center line. A pair of apertured flanges 31 extend from hinge bracket 2 for mountably receiving a hinge pin 9 which extends through flanges 31 and an apertured hinge clevis 32 extending upwardly from the tailgate door. Hinge pin 9 extends through flanges 31 and clevis 32, with the pin being maintained in position by suitable flat washers and cotter pins.

#As illustrated in FIG. 3, the aperture in clevis 32 is in the form of a horizontal, longitudinal slot 33 which is slightly larger than hinge pin 9. As an example, the hinge clevis slot 33 may be about two inches long by slightly more than one inch wide, while hinge pin 9 may be about one inch in diameter. This aids in enabling the tailgate door to pivot arcuately about the hinge until reaching a substantially vertical position, at which time the door can then be moved in a restricted horizontal manner substantially parallel into the door frame during locking, while preventing vertical movement of the door. A much tighter seal is obtained substantially around the entire perimeter of the door and vehicle door frame than in the prior art and without requiring time consuming shim adjustments.

#Tailgate door 1 includes a pair of vertical channel members 34 at each end, with each channel member containing longitudinal slots 35 therein for receiving a guide pin 7 carried by a locking ram 16 which slides vertically along the door and between channels 34. Each end of the locking ram is mounted to a respective sliding rod 36 at the top and bottom of the ram, with each rod 36 terminating in a rod eye 6 each with a horizontal latch pin 14 extending through respective slots in the channels 34 and through a top slot 37 and bottom slot 38 in an end plate 39 on the tailgate door. A latch 17 is mounted to the vehicle door frame and is provided for each latch pin as shown for instance in FIG. 2. FIG. 2 also clearly illustrates each latch pin in its locked position within a locking slot 40 provided on each of the latches. Also, as can be seen from FIG. 2, movement vertically upward of locking ram 16 moves the latch pins upwardly out of locking slot 40 and upwardly along end plate slots 37, 38. Each of the latches 17 are mounted to the vehicle by means of bolts 23 and suitable flat washers and lock washers. Longitudinal, horizontal slot 33 in door clevis 32 permits the door to move in a restricted horizontal manner, substantially parallel away from the door frame with latch pins 14 extending slightly upwardly on a ramp 41 leading to the locking slot provided on each of the latches.