Title:
LIGHTWEIGHT FORKLIFT
United States Patent 3563341


Abstract:
A forklift comprises a pair of upright posts which are secured through rack and gear means to a carriage that moves longitudinally of the posts and includes a pair of arms for positioning beneath a large load to be lifted. The arms on the carriage alternate with a pair of arms attached to the bottoms of the posts, and movable between positions beneath the lift arms and on opposite sides of the posts, as the base means in transmitting the load on the lift into the floor. A stabilizer structure is provided to prevent tipping of the lift.



Inventors:
BULTMAN FREDERICK H
Application Number:
04/738623
Publication Date:
02/16/1971
Filing Date:
06/20/1968
Assignee:
TENNECO INC.
Primary Class:
Other Classes:
187/236, 414/467, 414/540
International Classes:
B66F9/02; B66F9/06; B66F9/075; (IPC1-7): B66B9/20
Field of Search:
187/9,10,12,17,19,95 214
View Patent Images:
US Patent References:
3390797Means for attaching a lift truck to a lorry1968-07-02Goodacre
1701963High-lift truck1929-02-12Weaver



Foreign References:
GB627571A1949-08-11
Primary Examiner:
Hornsby, Harvey C.
Claims:
I claim

1. A lift device comprising a vertical frame, a carriage mounted for vertical movement on the frame, means acting between the frame and carriage for applying force to move the carriage vertically on the frame, said carriage including a lifting member projecting transversely to the frame, said lifting member having a bottom portion adapted to engage a floor, when said lifting member portion engages a floor operation of said force applying means acting to move the vertical frame relative to the carriage and lifting member, said frame including a base, a transverse base member movably supported by the base and including rollers engaging the floor, and a removable wheel assembly for connection to the base for rolling movement of the lift, said base member being shiftable from a position vertically beneath the lift member to a position located on the opposite side of the vertical frame when said vertical frame is moved relative to said carriage and lifting member.

2. A lift as set forth in claim 1 including a stabilizer means movable between an inoperative position and an operative position wherein the stabilizer means functions to prevent tipping of the vertical frame, said stabilizer means including lock means thereon for retaining the base member in a predetermined position on the base wherein the base member is located directly beneath the lift member.

3. A lift device comprising a vertical frame, a carriage mounted for vertical movement on the frame, means acting between the frame and carriage for applying force to move the carriage vertically on the frame, said carriage including a lifting member projecting transversely to the frame, said lifting member having a bottom portion adapted to engage a floor, when said lifting member bottom portion engages a floor operation of said force applying means acting to move the vertical frame relative to the carriage and lifting member, said vertical frame comprising a pair of parallel vertical posts and including a removable top cross member and fixed bottom cross member, said carriage comprising pairs of side plates embracing opposite sides respectively of said vertical posts, rack bars mounted on said vertical posts and pinions supported on said side plates in engagement with the rack bars, guide bars mounted on said side plates and engageable with said posts on the sides opposite to said rack bars, worm and wheel drive means mounted on said carriage for rotating said pinions, hollow base members secured to the bottoms of said posts and base arms mounted in said hollow base members and movable from positions beneath said lift member to positions located on opposite sides of the vertical posts from the lift member when said vertical frame member is moved relative to said carriage and lifting member.

4. A lift as set forth in claim 3 including stabilizers mounted on opposite sides of the carriage and adjustable vertically and angularly with respect to the carriage, said stabilizers including tubular members secured to the carriage and elongated rods projecting through the tubular members and having transverse feet at the bottom ends thereof, said feet including containing pins projectable into holes in the hollow base members and base arms to retain the base arms in position beneath the lift member.

5. A lift as set forth in claim 4 wherein the carriage member has a pair of downwardly opening U-shaped lifting members and said base arms fit inside said lifting members when the bottom portions of the lifting members engage a floor.

6. A lift as set forth in claim 5 including a removable wheel assembly for attachment to a hollow base member, said base arms including rollers for engagement with a floor.

7. A lift as set forth in claim 6 including removable extensions attached to the top ends of said vertical posts.

8. A lift device capable of climbing up and down between a floor surface and a higher surface and of use on each surface comprising a vertical frame, a carriage mounted for vertical movement on the frame, means acting between the frame and carriage for applying force to move the carriage vertically on the frame, said carriage including a lifting member projecting transversely to the frame, said lifting member having a bottom portion adapted to engage a said surface, when said lifting member bottom portion engages a surface operation of said force applying means acting to vertically move the vertical frame relative to the carriage and lifting member whereby said frame may be moved vertically from one surface to another, said frame including a base having a horizontally shiftable transverse surface engaging base member shiftable from one side to the other of said vertical frame.

9. A lifting device as set forth in claim 8 including a stabilizer mounted on the carriage and movable between an operative and inoperative position and in the operative position projecting from the frame in a direction opposite to that of the lifting member and adapted to engage said floor surface to prevent tipping of the frame when the device is climbing between said surfaces.

10. A lift device as set forth in claim 8 wherein said transverse base member has rollers for engaging a surface, and a removable wheel assembly for connection to the base for rolling movement of the lift.

11. A lift device as set forth in claim 8 wherein the vertical frame comprises a pair of parallel vertical posts and includes a removable top cross member and fixed bottom cross member, said carriage comprising pairs of side plates embracing opposite sides respectively of said vertical posts, rack bars mounted on said vertical posts and pinions supported on said side plates in engagement with the rack bars, guide bars mounted on said side plates and engageable with said posts on the sides opposite to said rack bars, and worm and wheel drive means mounted on said carriage for rotating said pinions.

12. A lifting device as set forth in claim 8 including surface engaging wheel means attached to the base to facilitate movement of the device on a surface.

Description:
BACKGROUND OF THE INVENTION

In the handling of heavy or bulky goods, such as large containers or parts, it has become conventional practice to use motorized lift or fork trucks which have a pair of lifting arms that fit beneath the container to be moved. Such trucks are relatively expensive and not economically justified for hundreds of small businesses which have a need for a forklift truck to lift and move large containers or objects from one point to another, such as from a trailer or boxcar to a warehouse area.

It is the purpose of the present invention to provide a relatively inexpensive forklift that may be moved and operated manually.

BRIEF SUMMARY OF THE INVENTION

The invention comprises a vertical frame that serves as a support for a vertically movable carriage that has lift members arranged for vertical alignment with and connection to a load to be lifted. The frame includes a shiftable base that can be moved to a position vertically beneath the lift members or to a position that is located on the opposite side of the vertical frame from the lift members. Preferably, the shiftable base fits inside of the lift members so that upon movement of the carriage relative to the vertical frame, either the base or the lifting member may be used to transmit the load on the truck onto the floor.

With this arrangement, the forklift of this invention can literally climb from the ground into the bed of a boxcar or truck and by providing the base member with wheels or rollers it can be moved around inside of the car or truck to carry parts or containers from one point to another. In use, it can be employed to move the load from a deep position in a truck to the back edge of the truck and then caused to climb down, while still carrying the load, from the truck onto the ground or floor and then moved away from the truck so that the load can be carried to storage or other desired location remote from the truck. Various other uses besides those associated with a truck or transportation vehicle are also possible, such as the arrangement of containers at different locations and different levels in a warehouse.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a forklift embodying the invention;

FIG. 2 is a perspective view on a reduced scale and partly broken away with the carriage in a partially elevated position as compared with the lift shown in FIG. 1;

FIG. 3 is an enlarged, broken away, persepective view showing the gear train for furnishing power to elevate the carriage;

FIG. 4 shows the forklift of this invention in a position as it is about to deposit a load upon (or lift it from) the bed of the trailer of a truck;

FIG. 5 shows the forklift of FIG. 4 as it begins its climb into the trailer;

FIG. 6 shows the forklift after it has been caused to climb into the trailer and in a position such that by hoisting of the stabilizers it can be moved about on the bed of the trailer; and

FIG. 7 is a perspective view showing an extension that can be put on the top of the vertical frame if it is desired to increase the total height to which loads can be lifted.

DESCRIPTION OF THE INVENTION

The manually operated forklift 1 of this invention has a vertical frame which includes a pair of vertical posts 3 and 5 which are preferably hollow, square tubes that are reinforced by a removable top crosspiece 7, likewise of a square, hollow construction. The bottoms of the posts 3 and 5 are welded to hollow open ended base tubes 9 and 11 which are substantially flush with one side of the posts but extend some distance away from the back sides 13 and 15 of the posts. Extending between and welded to the base tubes 9 and 11 is a straight cross tube 17 which along with the tubes 9 and 11 can rest on a floor to support the vertical posts 3 and 5. Also extending between and welded to the base tubes 9 and 11 is an arched cross tube 19 which has a straight portion 21 that includes a centrally located aperture 23. The aperture 23 will receive a pin (not shown) that projects vertically from a handle and wheel assembly 25 which includes a pair of wheels 27 that are supported by an axle on a rockable frame 33 carrying platform 29 which fits beneath the straight portion 21 of the cross tube 19. The platform 29 and the pin for positioning in aperture 23 may be moved to a connected position with the cross beam 19 by downward movement of the handle 31 which is pivoted on the axle of the wheels 27 through frame 33 and when this is done the posts 3 and 5 may be lifted slightly off the ground and the lift 1 moved manually from one position to another. Such movement is assisted by rollers 35 which are carried by the two base arms 37 and 39. The base arms are of square or rectangular construction and are extend through the hollow base tubes 9 and 11 and are loosely fitted in them so that they may be readily shifted from one side of the plane defined by the vertical posts 3 and 5 to the other side as is seen by comparing FIGS. 1 and 5.

The faces 41 and 43 of the vertical posts 3 and 5 are opposite to the faces 13 and 15 and have rigidly affixed to them by welding, bolting, etc. the rack bars 45 and 47 which are in horizontal or transverse alignment. A carriage construction 49 has a suitable drive and pinion mechanism 51 to mesh with the rack bars 45 and 47 so that operation of the mechanism will cause the carriage 49 to move up or down on the vertical posts 3 and 5. The carriage 49 includes a pair of side plates 53 which straddle the post 3 and a pair of side plates 55 which straddle the post 5. A pinion shaft 57 extends horizontally between and is supported for rotation by the side plates 53 and 55 and has keyed to it a pinion gear 59 between each set of side plates to mesh with the racks 45 and 47 so that rotation of the side gears 59 will cause them to climb up or down on the racks 45 and 47 thus elevating or lowering the carriage 49. Tilting of the carriage 49 with respect to the vertical posts 3 and 5 (or with respect to the horizontal) is prevented by a pair of rotatable guide bars 61 and 63 which are journaled in the side plate 53 and 55 and act with the pinions to transfer load into the vertical frame formed by posts 3 and 5. These include shouldered roller sections 65 and 67 that roll on the faces 13 and 15 of the posts and also embrace the sides of the posts so as to prevent undesired vertical or transverse misalignments of the carriage relative to the posts. The bars 61 and 63 along with crosspiece 68 also serve to rigidify the carriage by interconnecting the side plates.

A suitable worm and wheel assembly 69 (FIG. 3) may be used as a part of the drive assembly 51 and preclude movement of the carriage by the load. Thus, the wheel 71 may be keyed to the shaft 57 and driven by a worm 73 supported in the housing 75. The worm has a suitable socket or drive connection 77 (FIG. 1) that will receive either the end of an end crank 79 or a power operated rotary drive 80.

The forklift portion of the lift device 1 is provided by the two lift members in the form of cantilever arms 81 and 83 which are U-shaped in cross section and open downwardly. The inner ends are open and positioned between the side plates 53 and 55 and rigidly secured to them so that the arms 81 and 83 are an integral portion of the lift carriage 49. The lift arms 81 and 83 are wider and deeper than the base arms 37 and 39 so that, as seen in FIG. 6, the base arms can be completely covered inside of the lift arms 81 and 83. The bottom edges or surfaces of the lift arms 81 and 83 are adapted to engage the floor, even with the base arms inside, so that load on the carriage can be transmitted directly by lift arms into the bed 85 of the truck or trailer body 87 or into the floor on which the lift 1 is supported.

Secured to opposite sides of the carriage 49 are a pair of stabilizers 89 and 91. The stabilizers each include a support tube 93 which is welded to the outer of the side plates 53 and 55. A long, round rod 95 extends through each of the support tubes 93 and is vertically movable in it, being fixed in a desired vertical and angular stabilizing position (FIGS. 5 and 6) by means of the lock screw and handle device 97. The bottom of each rod 95 has a transverse foot 99 which is braced by the diagonal strut 101 that extends between the foot and the rod 95. Extending transversely of each strut 101 are angle bars 103 that have downwardly extending retaining pins that are used to extend through holes 105 and 107 in the base tubes 9 and 11 and the arms 37 and 39 to hold the arms in the optimum support position, i.e., beneath lift arms 81 and 83 as in FIGS. 1, 2, and 4. The removal of the retaining pins requires lifting of the stabilizers 89 and 91 and thus serves as a reminder to an operator to adjust the stabilizers to the positions of FIGS. 5 and 6 when the arms 37 and 39 are in the climbing position of FIG. 5 or in the elevated position of FIG. 6. Each foot 99 may have a floor engaging projection 109 to level it with pin 105 as seen in FIGS. 5 and 6. During movement of the carriage 49 on the posts 3 and 5 the latches 97 are in released position and weight of the bars 95 holds the pins 105 in place. The need to remove the stabilizers in order to shift the base arms reminds the operator to activate the stabilizers and serves as a safety feature.

The back ends of the base members 37 and 39 have flange plates 111 which will butt against the ends of the tubes 9 and 11 to align holes 105 and 107 and limit shifting of the arms. However, the base arms can be removed from the hollow tubes 9 and 11 by movement in the other direction. Likewise, the carriage 49 can be dismounted from posts 3 and 5 by cranking it off the tops of the posts. These dismantling features provide for compact storage and shipment of the lift 1.

In illustrating the operation of the lift 1, it will be assumed that it is desired to lift a carton 113 from the floor of a warehouse or shipping area onto the bed 85 of a truck trailer 87 and then move it from the rear 115 of the body to a point deeper inside the trailer. In order to simplify the drawings, the container 113 is not illustrated until the lift 1 is ready to deposit it on the truck bed 85 but it is a simple matter to visualize how the lift 1 will pick up a container 113 by moving the arms 81 and 83 into the space 117 between the parallel support bars 119 on the bottom of the container 113. The carriage 49 may then be elevated slightly by turning of the crank 79 or use of the power drive 80 to elevate the arms 81 and 83 a slight amount, as shown in FIG. 1. In the position of the lift in FIG. 1, the wheel and handle mechanism 25 in combination with the rollers 35 on the base arms 37 and 39 may be used to move the lift to a point adjacent the rear of the trailer body 87.

When the lift is positioned in alignment with the rear opening of the truck body, the carriage 49 is elevated as indicated in FIG. 2 until the carton 113 and its support bars 119 are slightly higher than the bed 85. At this point, the lift can be moved so that the arms 81 and 83 and the container 113 are inside the body 87, the posts 3 and 5 are substantially against the rear 115 of the trailer, and the base arms 37 and 39 are directly beneath the lift arms and the bed 85. The handle and wheel assembly 25 can be disconnected and removed and the lift will then appear as shown in FIG. 4. The carriage 49 can then be lowered until the bottoms of the lift arms 81 and 83 are on the bed 85 of the trailer. When this occurs, additional lowering force supplied to the mechanism 51 cannot be effective to lower the carriage 49 so instead the posts 3 and 5 and attached structure are elevated or lifted off the ground whereby the lift can climb into the trailer 87. Prior to such lifting of the posts, the stabilizers 89 and 91 must be disconnected from retaining holes 105 and 107 and they are preferably splayed out as shown in FIGS. 5 and 6 and locked in position by locks 97. When this is done, it is also possible to shift the two base arms 37 and 39 to opposite sides of the posts 3 and 5 so that as the posts and base tubes 9 and 11 are lifted, the inside ends of the arms will clear the back face 115 of the trailer body 87. When the arms 37 and 39 have been raised to the level of the bed 85, they can be pushed inside of the trailer body 87 so that they telescope inside of the arms 81 and 83 whereby the lift assumes the position shown in FIG. 6 wherein all the parts except the stabilizers have climbed inside the trailer body 87. At this point the hand-lock mechanism 97 can be released and the stabilizers elevated into a position such as seen in FIGS. 1, 2, and 4 and the lift 1 has now climbed into the truck and is in position to be moved about on the trailer bed 85.

In the case of unloading of the trailer 87, the procedure just described can be reversed to some degree and the base arms 37 and 39 made to climb down from the truck onto the ground in the stages shown in FIGS. 5 and 4. The container can then be lifted as seen in FIG. 4 and removed out of the trailer.

When the lift 1 is used for purposes other than loading or unloading boxcars or trailer bodies, such as to load storage racks in warehouses, it is possible to extend the height of the vertical posts 3 and 5 by means of extensions 121 and 123 as seen in FIG. 7. For this purpose the top cross bar 7 is provided with projections (not shown) which fit into the open ends at the tops of the posts 3 and 5 and are held there by lock pins 125 and 127. These can be removed and extension pieces 121 and 123 with suitable projections to fit in posts 3 and 5 can be inserted and locked in placed by the pins 125 and 127 and the top cross bar 7 attached by means of pins 129 and 131 to the tops of the extensions 121, 123. The extensions 121, 123 have rack bars 133 that form a continuation of the rack bars 45 and 47.

It will now be realized that the invention has provided a mobile forklift device that does not require an engine or motor and which can be moved about by human power. Additionally, it can climb from one level to another to facilitate the moving of heavy objects and containers. This is accomplished in a relatively simple construction, considering the results accomplished, which can be manufactured at a price that can be afforded by many businesses that are unable to financially justify the investment required in conventional powerized forklift trucks. Additionally, the conventional forklift is not capable of climbing between the floor and the bed of a truck. A further advantage is that the carriage, base arms, stabilizer rods, etc., may be disassembled from the vertical frame permitting relative flat and compact storage and shipment.

While the rack and pinion drive for the carriage is preferred because of its simplicity and built in safety features, it is also within the broad scope of the invention to operate the lift by means of cables or chains, electric winches, hydraulic lifts, or other powerizing means. A further modification of the specific structure, which may seem desirable in some cases, is to locate the base arms 37 so that they are displaced horizontally from the lift members 81 and 83 and therefore do not fit inside of them. However, the relative heights of the members and bars is such that load is taken on the lift members when the carriage has been fully lowered for floor contacting position.

Modifications may be made without departing from the spirit and scope of this invention.