Fork Lift Apparatus

Abstract

A fork lift apparatus for mounting on the front of a highway truck has its mast structure arranged to pivot about a longitudinal axis on the front of the truck for movement from a low-level horizontal traveling position to vertical and longitudinally inclined operating positions, mounting the fork supporting apron on the mast for pivoting about a longitudinal axis to provide for transverse tilting of the forks, and pivotally mounting the forks in variable positions on the apron for pivoting about vertical axes to permit their folding to a position transverse of the truck when they are not in use.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to fork lift apparatus and particularly to such apparatus arranged for mounting on the front of a highway automobile truck.

2. Description of the Prior Art

Conventional fork lift apparatus utilize a fixed vertically disposed mast, which renders it unsuitable for mounting on highway automotive trucks because a desirably high mast would interfere with driver visibility. The conventional fixedly projecting forks would be inconvenient and hazardous during street or road operation.

SUMMARY OF THE INVENTION

The invention provides a high rise fork lift apparatus applicable to the front of a highway truck. Among its features are a rotatable mounting for the mast whereby the mast can be swung from a horizontal traveling position transverse of the truck to a vertical operating position. It also includes means for tilting the mast longitudinally so as to assist in picking up loads and to stabilize heavy or large loads such as automobiles, and means for tilting the for,-mounting apron transversely to aid in discharging loads carried by the forks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation of a preferred embodiment of the invention, as applied to a highway truck, in traveling position.

FIG. 2 is a plan view of the embodiment illustrated in FIG. 1.

FIG. 3 is a side elevational view of the apparatus showing the vertical position of the mast mounting plate.

FIG. 4 is a side elevation corresponding to FIG. 3 but showing a rearwardly inclined position of the mast mounting plate.

FIGS. 5 and 6 are vertical sectional views along line 5--5 and 6--6 respectively of FIG. 2.

FIG. 7 is a horizontal sectional view along line 7--7 of FIG. 6.

FIG. 8 is a front elevational view of the apparatus in operating position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The apparatus comprises a pair of transversely spaced longitudinally extending channel members 1 which may be secured to the front end portions of the frame side rails of a truck T, the cab C of which is provided with the usual front sight S., S.

At their forward ends, which project forwardly from the front of truck T, channels 1 mount a transverse pin 3 and a mast mounting member comprising a transverse plate 5 provided on its rear surface with a pair of transversely spaced pierced ears 7 pivotally mounted on pin 3 to permit plate 5 to pivot about the axis of pin 3.

For selectively positioning member 5 in upright or inclined positions, it is formed, along each of its vertical sides, with rearwardly extending brackets 9 to which clevises 11 are pivotally secured by transverse pins 13. Clevises 11 are adjustably secured to piston rods 15 of hydraulic cylinders 17, which in turn are pivotally secured, by transverse pins 19, to upstanding brackets 21 on channel side rail extensions 1 rearwardly of plate 5, so that upon actuation of cylinders 17, member 5 may be selectively tilted between forwardly and rearwardly inclined and vertical positions.

On its forward face, member 5 is formed, near its left side, with a circular boss 23, and an upstanding bracket 25 on side rail 27 of a fork lift mast part is pivotally secured to boss 23 by longitudinally extending pin 29, so that the entire mast may be swung about pin 29 from a horizontal inoperative position (FIG. 1), substantially below front sight S to a vertical operating position (FIG. 8), substantially obstructing front sight S.

The mast part has a second side rail 31, which along with side rail 27 is of channel cross section, and rails 27 and 31 are connected by top and bottom cross bars 33 and 35.

For swinging mast 27, 31 from the horizontal inoperative position of FIG. 1 to the vertical operative position of FIG. 8, a hydraulic cylinder 37 is connected by longitudinal pivot pin 39 to the upper portion of mast mounting plate 5, above boss 23, and its piston rod 41 is formed with a clevis 43, which is connected by pin 45 to a bracket 47 on the upper or right-hand end portion of mast side rail 27.

Mast part 27, 31 is provided with a telescopic extension comprising side rails 49, also of channel section and slidably mounted within the channels of mast side rails 27 and 31, and top crossbar 51 connecting side rails 49.

For extending the telescoping mast structure to its full height, as shown in FIG. 8, after its lower portion has been swung by hydraulic cylinder 37 to the vertical position, a hydraulic cylinder 53 is mounted, parallel to the side rails, on bottom crossbar 35 and its piston rod 55 is connected to a cross head 57 secured to mast extension top crossbar 51 so that when cylinder 53 is energized, piston rod 55 pushes crosshead 57 and the entire mast extension 49, 51 upwardly with respect to mast lower portion 27, 31.

A vertically movable carriage 59 for supporting a fork-mounting apron is supported forwardly of mast lower portion side rails by vertically spaced pairs of rollers 63, and the carriage is connected to a pair of chains 65 which extend upwardly over sprockets 67 on crosshead 57 and downwardly therefrom to a dead-end connection on a connector bar 69 rigidly connecting mast lower portion side rails 27 and 31 so that, as cylinder 37 moves extension 49, 51 upwardly with respect to the lower portion of the mast, carriage 59 will move upwardly at a uniform rate with respect to both the mast lower portion and extension.

At its center, carriage 59 is provided with a forwardly extending circular boss 71, and transversely elongated rectangular apron 61 is pivotally secured to carriage 59 by a longitudinal pivot element 73 in said boss, thus permitting transverse inclination of apron 61 about the axis of pivot element 73.

Apron 61 comprises a vertical plate with a horizontal flange 75 along its lower margin, the outer margin 77 of the flange being bent upwardly and cut out at intervals to form a series of transversely spaced slots 79, while along the upper margin of the apron are secured, by their terminals, a similar number of U-shaped bars 81, vertically aligned with slots 79 and arranged to pivotally receive the upper ends of the vertical arms 82 of L-shaped fork members having horizontal arms 83. With this arrangement, fork members 81, 83 may be swung from a traveling position in which their arms 83 are transverse of the truck and resting in the channel defined by flange 75, to an operating position in which their arms 83 extend forwardly through slots 71 to form lading-supporting forks.

For selectively maintaining apron 61 and fork arms 83 horizontal or inclined transversely of the truck, a hydraulic cylinder 85 is pivotally connected by a longitudinal pin 87 to carriage 59 and its piston rod 89 is pivotally connected by pin 91 to one end portion of apron 61 so that, when cylinder 85 is energized, the apron may be tilted and maintained in the tilted or horizontal position.

OPERATION OF THE PREFERRED EMBODIMENT

For normal traveling, the parts of the apparatus are in the position shown in FIGS. 1 and 2, with forks 81, 83 folded against apron plate 61, with mast lower portion 27, 71 horizontal, mast support plate 5 vertical, and mast extension retracted, so that the device is substantially at the level of the usual truck bumper.

When it is desired to utilize it, forks 81, 83 are normally swung outwardly, after being positioned in the desired transverse locations. Hydraulic cylinder 37 is then energized to move the mast to a vertical position and cylinder 85 is energized to swing fork mounting apron 61 to a horizontal position transverse of the upright mast. If desired, cylinders 17 may be energized to incline the mast forwardly to enable the extended forks to scoop up the load then advancing the truck until fork arms 83 underlie the load. Cylinder 12 may then be reversed to stabilize the load and cylinder 53 energized to extend mast extension 49, 51 and elevate forks 81, 83 and the load to the desired height. After the load has been picked up and moved by truck T, cylinder 85 may be energized to tilt apron 61 and fork arms 83 to discharge the load, and the apparatus may be returned to its traveling position by a reversal of the steps described.

The details of the fork lift apparatus disclosed herein may be modified substantially without departing from the spirit of the invention and the exclusive use of any modifications as come within the scope of the amended claims is contemplated.

Claims

1. Fork lift apparatus for mounting on the front end of a vehicle comprising a mounting element, a mast part, pivot means mounting said mast part on said mounting element for transverse pivotal movement about said pivot means between a transverse horizontal inoperative traveling and storage position below the front sight of the vehicle and a vertical operating position substantially obstructing the front sight of the vehicle.

2. Fork lift apparatus according to claim 1 including second pivot means pivotally supporting said mounting element on an axis transverse of the axis of said first pivot means.

3. Fork lift apparatus according to claim 2 including a carriage movable lengthwise of said mast part, an apron, third pivot means pivotally mounting said apron on said carriage on an axis parallel to the axis of said first pivot means, and a pair of forks carried by said apron.

4. Fork lift apparatus according to claim 3 wherein said forks are mounted on said apron to swing between an inoperative position parallel to said apron and an operating position normal to said apron.

5. Fork lift apparatus according to claim 4 wherein said forks are of L-shape each having a vertical and a horizontal arm, and means pivotally securing said vertical arms to said apron for pivotal movements about the axes of said vertical arms.

6. Fork lift apparatus according to claim 5 wherein said apron has a flange along its lower margin, and the outer margins of said flange is bent upwardly to define an upwardly open channel, slots in the margin of said flange spaced apart transversely of said apron, there being a plurality of vertical axis pivot bearings on said apron vertically aligned with said flange slots and adapted to pivotally receive said fork vertical arms, said fork horizontal arms being received within said channel when said forks are folded and projecting through said margin slots when said forks are extended.

7. Fork lift apparatus according to claim 6 wherein there are a plurality of said slots and pivot bearings vertically aligned therewith spaced apart from each other transversely of said apron to permit variable positioning of said forks.

8. Fork lift apparatus according to claim 1 including a mast extension telescopically related to said mast part, a fork mounting apron movable lengthwise of said extension responsive to relative lengthwise movements of said mast part and said extension.

9. Fork lift apparatus according to claim 8 wherein a carriage mounted on said extension for movement lengthwise thereof supports said apron, there being a flexible tension member extending lengthwise of said extension, an antifriction element carried by the outer end of said extension, said flexible tension member passing over said antifriction element and having its opposite ends secured respectively to said mast part, whereby upon projection of said extension, said carriage moves toward the outer and upper end thereof and upon retraction, said carriage moves toward the lower end thereof.

10. Fork lift apparatus according to claim 1 including first power means connected to said mounting element and said mast part for effecting relative pivotal movements thereof.

11. Fork lift apparatus according to claim 2 including first power means connected to said mounting element and said mast part for effecting relative pivotal movements thereof and second power means connected to said mounting element for effecting pivotal movements thereof about the axis of said second pivot means.

12. Fork lift apparatus according to claim 3 including first power means connected to said mounting element and said mast part, and third power means connected to said carriage and said apron for effecting relative tilting movements of said apron.

13. Fork lift apparatus according to claim 1 including a pair of rails adapted for securement to the side rails of a vehicle underframe, and means supporting said mounting element on said rails.