Interposable Mast

Abstract

Boom-type lift vehicles, including such vehicles already existing, are convertible to boom-mast-type vehicles, by means of a mast having a simple connector system which enables it to replace removable forks leaving pivotal linkages at boom' s-end undisturbed. The mast has nonpivoting attachment to a frame which remains pivotally mounted at boom's-end. The replaced forks can be used on the elevator carriage of the mast.

Description

INTRODUCTION

The invention of which this disclosure is offered for public dissemination, in the event patent protection is available, relates to forklift vehicles of the boom type, and more particularly to a simplified means for increasing the height of lift available in such a vehicle by adding an elevating mast to it.

Forklift vehicles have commonly been of three types. In the mast type, the base portion of a telescopic mast is carried by the vehicle at a fixed level, a telescoping portion elevates beyond the base portion, and a carriage on the telescoping portion moves from the bottom to the top of that portion during the elevating operation. In the boom type, the boom is pivoted at its rear end to the vehicle, or preferably to reaching link on the vehicle, and the fork device is power-pivoted to the boom at its front end, this pivotal connection being used to keep the forks horizontal during the pivotal lifting of the boom, and preferably can also be used for dumping the forks. In the reaching version of the boom type, an upstanding "reaching" link can be power-pivoted to move the boom forwardly or rearwardly. The third class of forklift vehicles was a combination of the other two, a mast-on-boom type. Here the mast is pivotally carried at the front end of the boom and the lifting by the mast action can be added to the lifting by the boom. The mast is power-pivoted so it can be kept vertical during raising of the boom.

A great many forklift vehicles of the reaching boom type are already in service. Occasionally the owner of one of these wants a higher lift than is available from it. According to the present invention, it becomes quite easy for him to convert his boom device to a combined mast-on-boom device. The conversion and reconversion is so easy that if the owner expects to have a long period when he does not use the mast he may choose to remove it, since the presence of a mast constitutes some obstruction to the great freedom of maneuvering which is one advantage of the simple boom type of machine.

Because of the greater freedom of movement of the simple boom type of machine, a purchaser purchasing a combined mast-on-boom type may prefer to purchase it in the convertible form so that if he uses his machine under circumstances such when, for long periods, he does not expect to need the greater height provided by the mast he can convert to a simple boom type machine with its more unimpeded maneuvering. Even though it may be relatively rare that the upstanding mast at almost the very front of the vehicle would strike anything, if it is present the operator must be constantly on his guard to be sure that he has adequate clearance. Hence the mast is decidedly objectionable, when it is not needed.

There may have been prior structures which, with changes could have been convertible. For example U.S. Pat. No. 3,074,244 shows two forms which, perhaps only by hindsight, might have been made interchangeable. Such conversion would have been both more complex and more expensive than using the present conversion. One total front end assembly would have been removed from the boom and another put in its place. According to the present invention, the fork-carrying frame of the boom device remains on the boom. The forks alone are removed simply by pulling a shaft, the mast is secured in its place almost as simply as the forks are removed, and the same forks are reattached to the elevating carriage of the mast. As compared to the boom type of machine, a minimum of accessory equipment is required, namely the bare mast without even its own forks.

DESIGNATION OF THE FIGURES

FIG. 1 is an elevational view of a lift vehicle of the so-called reaching boom type.

FIG. 2 is an enlarged fragmentary elevational view of the boom-end portion of the vehicle illustrated in FIG. 1 after it has been converted in accordance with this invention to the boom-mast type.

FIG. 3 is a further enlarged fragmentary perspective view of the boom-end portion of the vehicle as converted in accordance with the structure illustrated in FIG. 2.

FIG. 4 is a still further enlarged fragmentary perspective view partially broken-away to illustrate details of the coupling structures at the lower portion of the permanent frame.

DESCRIPTION OF PREFERRED EMBODIMENT

Vehicle 10 illustrated in FIG. 1 includes mobile chassis 12, boom means 14, and fork 16. Boom 14 is secured by pivoting means 18 to pivoting link 20 which, in turn, is pivotally secured to chassis 12. Hydraulic piston means 22, 24, 26 serve to operate the boom 14 and elements associated thereto. Hydraulic piston means 22 powers the front-back reaching action of boom 14. Hydraulic piston means 24 powers the elevation of boom 14. Hydraulic leveler 26 secured pivotally at one end 28 to boom 14 is more or less permanently, and pivotally secured by pivot means 29 at end 30 to frame 32. In the illustrated embodiment, boom 14 includes terminal portion 35 which is fixed at an angle with respect to boom 14. The free end of terminal portion 35 of boom 14 is also pivotally, more or less permanently secured to frame 32, by means of pivotal securing means 38.

A fork-frame 32 is dependably, pivotally attached at boom's-end 35 and to the operating end 30 of hydraulic leveling unit 26. In the illustrated embodiment fork frame 32 is substantially rectangular, includes a pair of lateral sidewall members 40 and horizontally oriented structural members 42 at the top and bottom thereof. In the side views only the near elements are shown. It is to be understood, however, that the lift vehicle includes coacting piston means, especially reach means 22 and lift means 24, identical to those illustrated in FIG. 1, on each side of the vehicle, the corresponding members on each side being operable in unison, and boom parts more or less bridging across the vehicle to cooperate with both sets.

Spaced apart from side members 40 and closely adjacent thereto are secondary vertical framing elements 44. Between members 40 and 44 the pivotal connections 29 and 38 are secured. These pivotal connections 29 and 38, being more or less permanently secured, are preferably provided with means for lubrication, e.g., grease fitting 46, and may have seals to exclude water and dust.

Forks 16 include horizontal load-engaging portion 48, vertical portion 50. The upper extreme of vertical portion 50 is fashioned in the general shape of a loop 52. Plate-element 54 is welded between the vertical elements 40, 44 immediately inwardly of elongated openings 55 in members 40, 44. Thus, when fork 16 is secured to permanently attached frame 32, pin 57 passing through openings 55, through loop 52 in fork 16, and through second opening 55, vertical member 50 of fork 16 butts against plate 54 to limit downward pivot. However, it is apparent that mounting in accordance with the illustrated embodiment permits upward pivoting of forks 16. The particular mechanism by which forks 16 are secured to frame 32 may be conventional.

MAST ASSEMBLY

According to this invention, a mast assembly 60, usually telescopic, can be used with vehicles of the type described, in place of their forks.

In the illustrated embodiment, mast assembly 60 is of the conventional telescoping type including a base portion 62 into which upper, extendable frame 64 telescopes. Conventionally, upper frame 64 is moved in and out of base frame 62 by means of hydraulic piston means 66. Hydraulic piston means 66 is powered by means of hydraulic fluid conveyed through flexible conduit 70 which is attached to hydraulic piping 72 fixed to boom 14. Flexible conduit 70 is attachable to hydraulic piping 72 by means of quick disconnect fittings 74, as diagrammatically illustrated in FIG. 3. Such fittings 74 are commercially available and provide for almost instantaneous disconnect of conduit 70 from piping 72 with automatic closing of these elements when disconnected, and for automatic opening of the connection when terminal portions of lines 70, 72 are connected thereby.

In the conventional telescoping mast construction, a vertically movable carriage assembly 76, rides along the telescoping portion 64 of the mast structure. Carriage assembly 76 is moved, or perhaps more accurately, "suspended" within telescoping structure 64 on chains 78, one end of which is fixed to movable carriage assembly 76, the other end of which is fixed to base portion 60. Chains 76 pass over conventional sprockets mounted at upper end 80 of extendable telescoping frame member 64. Thus, as illustrated in FIG. 3, carriage 76, is positioned at the lower end 82 of base portion 62 of mast 60 when telescoping section 64 is retracted to a position fully within base portion 62. However when telescoping portion 64 is extended out of base portion 62 due to the pushing action of piston 66, one end of chain 78 remains fixed to base portion 62 and, because telescoping portion 64 and with it the sprockets referred to above, are moved upwardly with respect to base portion 62, chain 78, in the region secured to carriage 76, is likewise moved upwardly, but at twice the speed of portion 76 carrying with it carriage 76 so that it is also moved upwardly with respect to telescoping frame 64. Thus carriage 76 is in the position illustrated in FIG. 3, and in the position illustrated by broken lines in FIG. 2 when the telescoping mast portion 64 is in retracted condition, but is moved upwardly automatically to the upper portion 80 of telescoping portion 64 of mast 60, when the telescoping portion is extended.

In accordance with this invention, pins 57 may be pulled, the forks 16 removed, and the mast assembly 60, by its base portion 62 connected to frame 32 by reinserting pin 57. This pin now extends through main support arms 84 which are welded to base portion 62 of mast 60. Openings 86 in the extended portions 80 of arms 84 are sized to receive the pin 57. Secondary attachment arms 90 are also carried by base portion 62. Connector arms 90 are secured to upper portion of frame 32 as by bolts 92 through lugs 94 attached to horizontal member 42. Attaching these lugs preferably by welding is the only structural change which needs to be made in existing machines. Thus, base portion 62 of mast, generally 60, is secured nonpivotally through pin 57, and bolts 92, at two levels widely spaced apart. Hence the function of bolt 92 and pin 57 in securing mast 60, to boom 14, is purely that of fastening one element to the other, with no rotating or pivoting function. Thus, while mast 62 is disconnected from boom 14, it is not necessary to carefully protect the connecting members from contamination by dirt, grit, etc., and it is not imperative that the connecting members be carefully cleaned and lubricated as it would be, were the connections made through pivotal members.

OPERATION

An extremely large number of lift vehicles of the general type illustrated in FIG. 1 are presently in successful operation. Simple addition to 32 of fastening means 94 at the top end thereof, as by welding, and provision of hydraulic conduit means 72, 74, and conventional control elements (not shown because conventional) converts vehicle 10 to a condition in which these already available vehicles can be readily, conveniently, safely, converted to the boom-mast type referred to above.

To make the changeover from the reaching boom, mast free condition illustrated in FIG. 1 to the reaching boom-mast condition illustrated in FIG. 3, forks 16 are disengaged from frame 32 by withdrawal of pins 57. Frame 32 and mast assembly 60 are brought together with openings 55 adjacent openings 86. Pins 57 are reinserted through openings 55, 86 to secure arm 86 to frame 32. Arms 90 are then secured to lugs 94 by means of bolts 92, to complete the nonpivoting attachment of mast assembly 60 to frame 32.

Forks 16 are then attached to carriage 76 by aligning loop 52 with openings 96 and passing pins 97 through openings 96 and loop 52. Again, vertical portion 50 of forks 16 butt against a horizontal support member 99 when attached as described above to carriage 76. Upper facing portion 101 of carriage 76 serves to assist in the stabilization of the load, and to protect telescoping mast assembly 60, from the load.

Flexible hydraulic conduit 70 is then attached to hydraulic pipe 72 by means of quick disconnect element 74 and the entire unit is ready for operation.

ACHIEVEMENT

Thus, in accordance with this invention, widely available vehicles of the type illustrated in FIG. 1 are readily convertible to a greater variety of uses, and, in the illustrated embodiment, are convertible to a construction which permits substantial increase in height-reach of the unit, e.g., for reaching to an upper level in construction work or for higher vertical stacking. Moreover, the constant hazard occasioned by the presence of any mast, at the end of a boom, and the impediment of a mast to access to some places, can be avoided when the mast is not to be used by removing it. The versatility of the convertible vehicle of this invention is substantially increased over nonconvertible vehicles. Moreover, in accordance with this invention, none of the pivotal connections such as 29 and 38 need to be disturbed. This is advantageous in several respects.

Claims

I claim:

1. In a lift vehicle, of the boom-mast type, having hydraulic pump means, and having boom means having two ends thereof, one end of said boom means being pivotally mounted to the vehicle, the other end being elevatable and free, said vehicle having mast means secured to the free end of the boom means, said vehicle having leveling means associated with the free end of the boom means and with the mast means, said vehicle including carriage means elevatably secured on said mast means, and having load-engaging means releasably secured to said carriage means, the improvement comprising:

mounting frame means pivotally secured at the free end of the boom means and operatively associated with the leveling means, the boom means and leveling means being permanently attached to said mounting frame means;

first receiving means on said mounting frame means for nonpivotally, releasably securing said mast means thereto;

said mounting frame means including means from maintaining respective elements of the boom means and of said leveling means in operating spatial relationship with each other;

said mast means and said frame means being self supportable as structurally integral units independently of each other;

drive means for moving said load-engaging means in a direction which is parallel with respect to said mast means, said drive means including power conduit means having a releasable connection therein near said mounting frame means;

second receiving means on said mounting frame means for releasably securing said load-engaging means to said mounting frame means in the absence of said mast means thereon.

2. In a lift vehicle, of the boom-mast type, having hydraulic pump means, and having boom means with two ends thereof, one end of the boom means being pivotally mounted to said vehicle, the other end being elevatable and free, mast means secured to the free end of the boom means, said vehicle having leveling means at the free end of the boom means, said leveling means being operatively associated with said mast means, carriage means elevatably secured on said mast means, load-engaging means releasably secured to said carriage means, the mast means including a base portion and an extendable telescoping portion thereof, said carriage means being secured to said extendable portion thereof, said vehicle including hydraulically powered and controlled means for cooperatively extending the telescoping portion of the mast with respect to the base portion of the mast and simultaneously elevating said carriage means with respect to said telescoping portion of the mast, the improvement comprising:

mounting frame means pivotally secured at the free end of the boom means and operatively associated with said leveling means, said boom means and leveling means being permanently attached to said mounting frame means;

first receiving means on said mounting frame means for nonpivotally, releasably securing said mast means thereto;

said mounting frame means including means for maintaining respective elements of said boom means and said leveling means in operating spatial relationship with each other;

said mast means and said frame means being self supportable as a structurally integral unit independently of each other;

said hydraulically controlled drive means including hydraulic conduit means having a releasable connection therein near said mounting frame means;

second receiving means on said mounting frame means for releasably securing said load-engaging means to said frame in the absence of said mast means thereon.

3. In a lift vehicle, of the boom-mast type, having boom means with a secured end and a free end, the secured end being pivotally mounted to the vehicle, the free end being elevatable, said vehicle including means for elevating the boom means, and including mast means secured to the free end of the boom means, carriage means elevatably secured on said mast means, load-engaging means secured to said carriage means, powered means for manually controlled operation of said carriage means, the improvement comprising:

mounting frame means pivotally secured at the free end of the boom means and operatively associated with said leveling means, said mounting frame means being substantially rectangular and having an upper and lower horizontal portion thereof;

first and second releasable attaching means for nonpivotally securing said mast means to said mounting frame means, the first attaching means being positioned adjacent the lower portion of said frame and including means for receiving a connecting portion of said mast means, and alternatively for receiving a connecting portion of said load-engaging means in the absence of said mast means thereon, said second mast-engaging means being secured adjacent the upper horizontal portion of the frame, said drive means including power conduit means having a releasable connection therein near said mounting frame means.

4. In a lift vehicle of the boom-mast type, having boom means with a secured end and a free end, the secured end being pivotally mounted to the vehicle, the free end being elevatable, said vehicle including means for elevating the boom means, and including mast means secured to the free end of the boom means, said vehicle including leveling means associated with said free end of said boom means and with said mast means, carriage means elevatably secured on said mast means, load-engaging means secured to said carriage means, drive means for moving said carriage means with respect to said mast means, the improvement comprising:

mounting frame means pivotally secured at the free end of the boom means, and operatively associated with said leveling means, said mounting frame being substantially rectangular and having an upper and lower horizontal portion thereof;

first and second releasable attaching means for nonpivotally securing said mast means to said frame means, the first attaching means comprising a nonrotatable arm secured to a lowermost portion of said mast means, mating means for securing said arm to detent means positioned adjacent the lowermost portion of said mounting frame means, said second mast-engaging means comprising nonrotatable arm means secured to said mast means at a point spaced far apart from said first mast-engaging means and comprising detent means fixed to the upper portion of said mounting frame means for mating with said second arm means, said load-engaging means comprising forks releasably secured to said carriage means, said forks having means for engaging said first detent means;

drive means for moving said load-engaging means with respect to said mast means, said drive means including power conduit means having a releasable connection therein near said mounting frame means.

5. A self supportable mast for use in conjunction with a convertible lift vehicle of the boom type, said vehicle having a hydraulic pump, said vehicle having a receiving frame pivotally secured to the operating end of a boom on said vehicle, said receiving frame releasably carrying load-engaging means secured thereon by releasable securing means on said frame, said mast including:

telescoping vertical members;

carriage means movably secured to the telescoping members;

load-engaging means carried by said carriage means;

hydraulic power means for operating said telescoping members and said carriage means;

hydraulic connection means in said power means for operatively connecting elements on the mast to said pump on said vehicle, and for disconnecting said elements from said pump;

first attachment means for engaging said securing means for nonpivotally securing said mast to said receiving frame; and,

second attachment means for attaching the load-engaging means to the carriage, the second attachment means being substantially identical to said securing means.

6. A material handling vehicle including a chassis and a boom pivoted at its rear portion to the chassis, a frame pivoted to the front end of the boom, means for changing the angularity of the frame as to the boom as the boom swings up and down, forks or other load-engaging means carried by the frame and secured to it by a removable pin;

and a mast for attachment to the frame when the load-engaging means have been removed, the mast having support and securing formations on its rear side for engagement by said pin upon restoring the pin, and having on its forward side an elevating carriage movable along the mast and provided with formations for receiving said forks and securing them with another pin;

said mast having hydraulic piston means for the raising of the carriage, and said vehicle and boom having a pump and conduit means extending approximately to the frame and provided with quick disconnect means for connection with the piston means.

7. For cooperation with a material handling vehicle of the boom type having a frame pivoted with he boom and provided with means for changing the angle of the frame with respect to the boom as the boom swings up and down and having hydraulic pressure means including quick disconnect means in the vicinity of the frame, the frame having a removable pin for securing forks or the like thereto:

a mast having on its rear side formations adapted to receive the pin upon being restored after removal of the load-engaging means, having piston means adapted to be connected to said quick disconnect means, having a carriage adapted to be raised and lowered along the mast by the piston means, and said carriage having a removable pin and formations for receiving the load-engaging means removed from the frame;

said formation and pin of the carriage being matingly similar to the formation at the rear of the mast whereby the mast and the load-engaging means which fit its carriage will be interchangeable on the frame.