US2200436A - Truck tail-gate lift - Google Patents

Description

y 14, 1940- c. WLVAN BLARcoM ET AL 2.200.436

TRUCK TAIL-GATE LIFT Filed Aug. 6, 1937 4 Sh ets-Sheet l May 14, 1940- c. w. VAN BLARCOM EIAL TRUCK TAIL-GATE LIFT Filed Aug. 6, 1937 4 Sheets-Sheet 2 y c. w. VAN BLARcoM ET AL 2.200.436

TRUCK TAIL-GATE LIFT Filed Aug. 6, 1957 4 Sheets-Sheet 4 I II y.

. Patented May 14, 1940 UNITED STATES 2,200,436 TRUCK TAIL-GATE LIFT Charles W. Van Blarcom and William A. Harris.

" Boonton, N. J.

Application August 6, 1937, Serial No. 157,802

6 Claims.

Our invention relates to an improvement in truck tail-gate lifts.

The object is to provide hydraulic means for raising and lowering gates, such as tail-gates or v tail-boards 'of trucks, vans and the like, and the invention consists in means for lowering the tailate or tail-board from the fioor level of the vehicle to which it is applied to the ground, and for raising it from the lowered position to normal.

With theforegoing objectv in view, this invention consists in features which will be specifically described'and set forth in the following specification. 1 e

In the accompanying drawings: :F'ig. 1 is a view in perspective}.

Fig. .2 is a rear View partly initra tical section;- r

Fig. 3 is a longitudinal section ofthrear end of a truck showing parts in elevation; Fig. 4 is a horizontal section showing the hydraulic reservoir, pump, piping and connected parts in dotted lines, and the gate in full lines;

Fig. 5 isan enlarged vertical section through the valve 21 and spring-controlled valve 28 to the one of the hydraulic cylinders; and

.Figs. 6, ,7 and 8 are detail sectional views showing the cylinders, anti-friction guide-rollers and connected parts.

The letter A representsthe rear end of a truck 1 or van, and the numeral l, the end-gate. The

end-gate I is hinged to a movable sill 2, and a chain or other means 3 affords support at each end to maintain its horizontal position when in operation, and to permit it to swing on its hinge 4 and to permit'it to be raised to vertical position when not in use.

The numeral 5 represents the hydraulic cylinders. One is stationed in each rear comer of the vehicle, and they are fixed in place by braces 6 or other suitable means. Columns 1 are located in each rear corner parallel with the cylinders, and preferably just at the rear thereof, and their lower ends are connected withthe. sill 2. These columns areguide'd; in their up and down movement by brackets 8 which embrace the cylinders and carry the anti-friction guiderollers 9 as viewed in detail in Figs. 6, 7 and 8. I

The cylinders preferably extend below the floor Ill of the vehicle and carry guide-rollers II against which the columns I move when lowered as indicated in Fig. 3.

Pistons l2 are fitted to the cylinders, and extending upwardly therefrom through the cylinders are the piston rods I3.

A head I4 is secured to the top of each bracket 8,. and each headv is provided with an arm I5 which extends over and in the path of the piston I3, see Figs. 5, 6 and 7, and a bolt I6 rigidly secures the brackets 8 to the columns I. The'upper ends of the cylinders are slotted down as shown at H a distance equivalent to the 5 range of movement of the gate l to afiord the required clearance for the arm I5 which moves up and down therein, and is guided thereby.

A reservoir R is-filled through a filler I9 (see Fig. 4), and a pump P circulates the fluid through 10 the pipe' system. The reservoir R, pump P, and

the pipe system are indicated in dotted lines in Fig. 4. The pump is driven from the power plant (not shown) through the shaft 20, and the fluid from the reservoir is supplied to the cylinders by pipe 22 and branches 23 discharging preferably in the lower ends of the-cylinders,

Each cylinder is provided with an overflow pipe 24, the upper end of which is beyond the highest v point of the piston stroke and below the slot IL,

and these overflow'pipes lead back to a common pipe 25 which discharges into .the reservoir R. A pipe 26 from the pump forms a circuit through pipe 22, and a return pipe 29 leads back tothe 25 reservoir, and the pump is supplied through a pipe 30 extending from the reservoir to the pump.

These valves are controlled, and the end-gate is operated, by the mechanism which will now be described: 30

A rock-shaft 3| extends across the rear of the vehicle and is turned. by the operator by the removable handle 32, so that it can be operated from either side of the vehicle. The sill 2 normally rests on a sliding spring-actuated bolt 33.

This is connected by means of a chain or cable 34 to a rocker 35 which is pivoted to a bracket 36 by a pin 31, and a connecting-bar 38 extends from the rocker-35 to the crank-arm 55 secured on the rock-shaft 3|. Levers 39 secured to the rock-shaft 3| are connected by connecting-rods 40 and 4| to the valves 21- and 28 respectively, all of which is illustrated in flull lines in Fig. 3 1 and in dotted lines inFig. 4. The numeral 42 is a check-valve.

- 45 Operation.--To move the gate, the power operator connects the power take-off with'thepump by throwing a shaft lever in the cab. When this shall have been done, the pump P. which is directly connected with. the power take-01f shaft begins to function, drawing fluid from the reservoir R and forcing it through the pipe 26 and spring-controlled valve' 28 which is normally open through the pipe 29 back to the reservoir, that is to say the fluid is circulated from reservoir to pump through pipe 3|! and back through the valve 28 to the reservoir. The tail-gate i is lowered to horizontal, where it is supported by the chains 3.

In order to lower the gate from the truck floor level to the street, the operator turns the handle 32. This draws the spring-actuated bolts 33, and through the connecting rod 4| the valve 21 is opened. This permits the fluid to run out of the cylinders 5 through the pipes 22, 23 and 29 back to the reservoir R. This lowers the piston i 2 in the cylinders, and the tail-gate i, which is indirectly connected thereto through the piston-rods i3 and the arms I 5 and the columns 1.

The speed of operation may be controlled by the size of the orifice of the pipes, or, if desired, by a special adjusting valve (not shown) which might be employed in the vicinity of the valve 21, or by throttling-valve 21 by means of control handle 32. The speed is regulated by the operator according to the load.

During raising as well as lowering, one or several times, the pump P is connected through the power take-off to the truck motor. The pressure relief valve 44 (see Fig. 4) and by-pass 45 are provided to permit stalling and insure against damage.

To raise the gate from the lower position indicated in dotted lines in Fig. 3, the car operator turns the shaft 3| by means of removable handle 32, thereby closing valve 28. This forces fluid through the check-valve 42, thence through the pipe 22 and branches 23 to the cylinders 5, This forces the pistons i3 upward, and as the arms l5 are in their path and these are connected through the heads II to the brackets 8 secured to the columns I, the latter are raised, carrying with them the sill 2 to which the tail-gate l is hinged. When the end gate has struck against the bolts 33 and stops located on truck floor, the control handle automatically returns to a neutral or vertical position.

From the foregoing, it will be observed that the cylinders perform a double function, the lower ends being used for power, and the entire length forming guides for the movable columns I which carry the end-gate, and the lowerends of the cylinders being provided with anti-friction rollers to form guides and lateral supports for the columns.

As it has been pointed out, turning the rockshaft 3| toward the rear opens the spring-actuated valve 28, and the spring returns the valve to its normally closed position when the end-gate has reached its elevated position.

In lowering, the same rock-shaft 3| is employed, and as it is turned toward the front of the truck, opens the valve 21 immediately following the drawing of the spring bolts 33.

The pump operates continuously until the shiftlever in the cab disengages it through the power take-off gears.

It is understood, of course, that while this has been called an end-gate, and it is shown and described as applicable to the end of a truck, van, or other type of vehicle, it would be just as applicable to a side door as a rear end door. Also it is understood the mechanism might be operated electrically. The only difference in the method of-operation with an electric motor is that the control handle starts the motor when raising the lift and automatically shuts it of! when the limit of travel is reached, or the stops are struck) by releasing the switch which cuts the circuit to the motor starter. When the lift is being lowered, the motor is not running. The operator merely valves the fluid from the cylinders by means of the control handle. It is entirely automatic.

We claim:

1. Mechanism of the character described comprising guide cylinders, pistons and piston rods operating therein, columns slidably connected with and guided by the cylinders, a sill connecting the lower ends of the columns, a gate connected with the sill, spring-actuated slide bolts in position to support the sill when in its elevated position, a fluid supplysystem connected with the cylinders, a pump foreirculating the fluid, valves for controlling the direction of movement of the fluid, a shaft and connections therefrom to the valves and the bolts, and means for actuating the shaft whereby to release the bolts and to operate the valves.

2. Mechanism of the character described comprising guide cylinders, pistons and piston rods operating therein, columns slidably connected with andguided by the cylinders, a sill connecting the lower ends of the columns, a gate con nected with the sill, spring-actuated slide belts in position to support the sill when in its elevated position, a fluid supply system connected with the cylinders, a pump forcirculating the fluid, valves for controllingthe direction of movement of the fluidpa shaft and connections therefrom to the valves and the bolts, means for actuating the-shaft whereby to release the bolts and to operate the valves, the means for actuating the bolts and valves including a rocker, a connectingrod extending therefrom to the shaft, an arm, and rods extending from said arm to the valvestem.

3. The combination of cylinders,pistons and piston rods therein, and columns, the cylinders fixed and forming guides, the columns having brackets thereon, anti-friction rollers carried by the brackets and embracing the cylinders whereby to facilitate the movement of the columns with respect to the cylinders, heads secured to the columns and having arms which project into the cylinders in the path of the pistons which arms are adapted to be engaged by the piston rods and be moved thereby, and hydraulic means for controlling the movement of the pistons and piston rods, and a gate carried by the columns.

4. The combination of a vehicle, cylinders flxed rigidly therein, pistons in the cylinders, pistonrods extending from the pistons, and the lower ends of the cylinders extending below the floor of the vehicle and carrying anti-yfriction rollers at their lower ends, columns slidably connected with the cylinders and having means projecting in the path of the piston rods adapted to be engaged by, the latter to raise the columns, a

sill connected with the columns, a gate supported by the sill, a hydraulic system and valves for controlling the passageof fluid therethrough, and means within the control of the operator for operating the valves.

5. The combination of a vehicle, cylinders fixed rigidly therein, pistons in the'cylinders. pistonrods extending from the pistons, and the lower ends of the cylinders extending below the floor of the vehicle, columns slidably connected with the cylinders and having means projecting in the path of the piston rods adapted to be engaged by the latter to raise the columns, a sill connected with the columns, agatesupported by the sill, a hydraulic system and valves for controlling the passage of fluid therethroush, and means within the control of the operator for operating the valves.

6. The combination of fixed cylinders, pistons and piston rods operating therein, a portion at.

least of the cylinders having longitudinally slotted sides, columns guided by and movably connected with said cylinders, and having means extending through the slots in the cylinders in the path of the pistons, whereby the columns are moved with the movement of the pistons and piston rods, an end-gate, means for hingedly connecting the endgate with the columns, and fluid pressure means for controlling the movement of the pistons and piston-rods' and the end-gate carried by the I columns.

CHARLES W; VAN BLARCOM. WILLIAM HARRIS.

Images