60/088,530 filed June 8,1998 which is incorporated by reference herein in its entirety.

Field of the Invention This invention is directed towards a method and apparatus for a vehicle mounted hoisting system. More particularly, this invention is directed to a boom which pivots along a frame carried within a cargo area of a vehicle. The pivoting motion allows a boom supported winch to engage, lift, and transport cargo between the cargo area of the vehicle and the exterior of the vehicle.

Background of the Invention A variety of lift mechanisms are known which purport to facilitate the movement of heavy cargo to and from a vehicle. For instance, moveable hoists, similar to that disclosed in U. S. Patent No. 5,028,198 to Buhr, have been used as a cargo lifting and placement apparatus for a pickup truck.

However, such hoists are mechanically complex and interfere with other uses of the cargo bed of the truck.

U. S. Patent No. 5,743,702 to Gunderson provides a sliding rail system for a truck bed from which a hoist may be suspended. However, the framework which supports the retractable hoist greatly restricts the height of an article which may be transferred by the hoist and rail assembly.

U. S. Patent No. 4,383,791 to King, which is incorporated herein in its entirety by reference, is directed towards a pivot-mounted boom carrying a

hoist and which is secured to the bed of a pickup truck. The boom is pivotally mounted near the trailing end of a vehicle. Hydraulic cylinders move the boom from a rest position within the interior of the truck bed to an operative position wherein the boom and hoist extend beyond the open tailgate of the truck. However, the structural design of the boom and hoist structure set forth in King has limitations on the amount of weight which can be safely transported without causing damage to the vehicle or risking injury to the operator.

Accordingly, there remains room for improvement and variations in the art.

Summary of the Invention The present invention provides an improved hoist and lift mechanism for a cargo vehicle which is of a simplified design and construction. The lift mechanism is capable of transferring cargo items weighing 1500 pounds (680 Kg). The lift mechanism of the present invention provides a rectangular support frame having a rear section which is secured through the cargo bed to the vehicle frame near the trailing end of the vehicle.

A forward section of the support frame is secured through the cargo bed to a cross-member of the vehicle frame, which thereby favorably distributes the lifting and moving forces in a manner consistent with the construction of the vehicle.

The design of the current lifting mechanism is an improvement over similar prior art designs in that the design enables heavier loads to be engaged and moved in a manner which avoids damage to the vehicle. Further, the lifting apparatus may be operated by a single individual.

The lift mechanism of the present invention is a hoist designed for placement surrounding the cargo area of a vehicle. The hoist includes a

lower rectangular frame which includes a first lateral frame member and a second lateral frame member adapted for securement in a parallel and traversely spaced apart relationship within the cargo area of a vehicle. The lateral frame members are used to position a boom having a first rail, a second rail and an interconnecting terminal cross- member. The boom is supported above the frame in a resting position and, when in the resting position, is substantially coplanar with the support frame members. A pair of stanchions or braces are attached to a terminal end of each rail member and are in further communication with a respective lateral frame member. Each member of the pair of braces supports a hinge which is in communication with a terminal end of the respective rail members.

An actuator, such as a hydraulic piston, is in operative engagement with at least one of the rail members.

The boom has disposed thereon a winch such that when the actuator moves the at least one of the first rail or second rail, the boom pivots along the pivot connections of the first rail and second rail as carried by the brace. The movement generated by the actuator thereby moves the boom and winch along an arcuate pathway which extends along a position above the cargo area of the vehicle to a position remote from the cargo area.

As a result, the winch may be used to engage an article for lifting and movement between the cargo area of the vehicle and the exterior of the vehicle.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.

Brief Description of the Drawings Fig. 1 is a perspective view of a pickup truck having the lifting apparatus of the present invention supported thereon and shown in an operative condition; Fig. 2 is a rear perspective view of the truck and lifting apparatus as illustrated in Fig. 1; Fig. 3 is a partial perspective view of the left rear of the truck and lifting apparatus as illustrated in Fig. 1 and showing the invention in an operative position with a cargo item suspended beyond the rear edge of the vehicle; Fig. 4 is a rear perspective view of the assembled components of the invention as seen removed from the installed configuration of the truck environment; Fig. 5 is an enlarged view seen along the direction of line 5-5 of Fig. 4; Fig. 6 is a perspective view in partial phantom of the connecting bracket and associated structures as seen in the direction of line 6-6 of Fig. 4; Fig. 7 is a left side elevation of the fixed frame elements of the lifting apparatus of the current invention and setting forth details of attaching the rear frame element to the undercarriage of the vehicle; Fig. 8 is a rear elevation of the frame components taken along the direction of line 8-8 of Fig. 7; Fig. 9 is an enlarged exploded perspective view as indicated in Fig. 7 and setting forth additional details of the attachment mechanism for the present invention; and Fig. 10 illustrates an alternative securing clamp for attaching the rear frame elements of the lifting apparatus to a frame member of the vehicle.

Detailed Description of a Preferred Embodiment Reference now will be made in detail to the embodiments of the invention, one or more examples of which are set forth below. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

Other objects, features and aspects of the present invention are disclosed in or are obvious from the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary constructions.

In reference to Fig. 1, a cargo vehicle, seen here in the form of a pickup truck 22, is set forth having a cargo bed area 24 defined within the enclosure set forth by opposite lateral walls 25, a cab wall 27, and tailgate 28. Wheel wells 26 extend into the cargo area 24 in a conventional fashion.

As further seen in reference to Figs. 2 and 4, lifting apparatus 20 is supported within the cargo area 24 by a rectangular frame comprising two lateral support members 62 and 64 seen here secured in a transversely spaced apart, parallel

relationship. A pair of uprights 70 engage a respective front end of corresponding support members 62 and 64. A plate-like foot 71 engages a floor of the cargo bed and further defines a plurality of apertures for attaching the plate to a lateral cross-member beneath the truck bed as will be set forth in greater detail below. Uprights 70 are connected to each other by cross-members 72 and 74 which may be either bolted or welded in position. As seen in Figs. 1 and 2, the uppermost cross-member 72 is substantially flush with the upper perimeter of the truck bed edge walls 25.

Cross-member 72 may be fastened to the cab wall 27.

Further, an optional protective window screen may be attached to cross-member 72.

A terminal end of lateral frame members 62 and 64 are engaged by a respective brace 66 and 68. As best seen in reference to Figs. 5 and 6, braces 66 and 68 each comprise a pair of oppositely spaced plates defining an opening 67 therebetween. As seen in reference to Fig. 6, brace 68 defines a ledge 69 which supports frame member 64. A similar ledge 69 is defined by brace 66. Ledge 69 provides a surface for securing support members 62 and 64 to the respective braces 66 and 68 by bolts 61 as seen in Figures 5 and 6.

Braces 66 and 68 each define an elevated, rearwardly projecting terminal shoulder 110 having a respective pivot pin 40 inserted therethrough.

Each raised shoulder may extend above the truck bed sidewalls and may further extend beyond the edge of the closed tailgate 28 approximately 6 inches (15.2 cm.) or more (Fig. 3). Each pin 40 provides a hinged attachment which may be used to secure a terminal end of the respective first rail 32 and the second rail 34 as seen in reference to Fig. 2.

Each rail 32 and 34 extends substantially the

length of the truck bed, where the terminal, non- pivoting ends of rail 32 and 34 are interconnected by a pair of front rails 36 thereby forming an inverted U-shaped boom 30. Front rails 36 may be welded or bolted to the corresponding side rails 32 and 34.

A winch 50 is carried by a midpoint of front rails 36 via an L-shaped attachment plate 51.

Winch 50 may be of conventional construction such as a pneumatic or electrically operated winch having an elongated cable 52 wrapped around a drum (not shown). In one embodiment, the drum is rotated by an electric motor. A free end of cable 52 carrying a hook 54 is secured to a fixed O-ring 56. A hook and pulley combination 58 moves freely along the unrolled length of cable 52.

As seen, boom 30 carries winch 50 so that as the boom pivots along the length of the truck bed, the winch is operatively positioned above a length of the truck bed and, when fully extended, projects beyond the rear of the truck cargo area. Tie downs seen in the figures as eye hooks 95 help secure the cargo within the truck bed.

An actuator, seen here in the form of pneumatic cylinders 80, are operatively disposed within the interior space 67 defined by each brace 66 and 68 and as best seen in reference to Figs. 5 and 6. The lower ends of each cylinder 80 are pivotally connected to the corresponding brace by hinge pin 81. A free end of each cylinder rod 82 is pivotally connected by pin 83 to a respective bracket 31 which may be welded or otherwise attached to a lower surface of each rail 32 and 34.

As best seen in reference to Figs. 3 and 6, when cylinder rod 82 is fully extended from cylinder 80, boom 30 is held in its maximum extension by the action of the pneumatic cylinders 80.

As seen in reference to Fig. 5, both hydraulic cylinders 80 are operated in tandem through a single hydraulic system which includes a reservoir 90 and spigot 96 in fluid communication with a hydraulic pump 92 controlled by pump motor 94. T- connectors 93 are used to interconnect the hydraulic lines 91 to allow simultaneous control of the respective upper and lower reservoirs associated with cylinders 80.

The pressurized flow of hydraulic fluid into the upper and lower pressure chambers within each cylinder may be regulated by a solenoid valve (not pictured) (Model No. CP350-3P-B-3P-4-12DV, Compact Controls, Inc., Hillsboro, Oregon 97124 USA) which is a three-position, four-way spool-type direct acting valve. The solenoid valve provides a control mechanism for regulating the hydraulic fluid flow from pump 92 through the hydraulic circuit.

The hydraulic pump 92 may have a restrictor plate or valve which limits the pump flow rate. It has been found useful to limit the flow rate of hydraulic fluid from the pump so that the hydraulic cylinders operate at a controlled rate. For instance, it has been found desirable to limit the boom travel rate so as to provide an approximate 30 second cycle time from raising the boom from a standard retracted position (Fig. 4) to the fully extended position (Fig. 3) in which the boom extends beyond the tailgate of the truck.

The hydraulic circuit may also have an additional flow restrictor to avoid pressure build- up within the hydraulic cylinder. It has been found that without a flow restrictor, a loaded boom may create additional pressure inside the hydraulic cylinder which increases the hydraulic fluid flow rate from the cylinder. The increased flow rate

results in an increased boom speed as well as sudden changes in speed, causing the suspended load to potentially swing out of control. By limiting the flow rate within the hydraulic pathway, undesired pressure surges and build-ups are eliminated and the boom and any engaged load move at a safe, constant predictable speed.

Each hydraulic cylinder 80 may also comprise a conventional internal pressure relief valve (not shown). The relief valve is calibrated to allow the boom to engage and carry a suspended weight of 1500 pounds (680 Kg). If a weight or obstruction is encountered which exceeds the system's designed safety parameters, the relief valve will direct hydraulic fluid to the reservoir 90. The passage of fluid to the reservoir under excess load conditions avoids misuse of the boom and prevents pressure-related heating of the hydraulic fluid which may damage rubber seals within the hydraulic circuit.

It has also been found useful to provide hydraulic cylinders having cushioned bottom cylinders as are known in the art. The cushioned cylinders make use of an internal flow restrictor that limits the fluid flow rate over the approximate last inch (2 to 3 cm.) of the cylinder rod travel when the rod is withdrawn to its minimum length. Suitable cylinders and hydraulic systems which incorporate the above features are available from Fenner Fluid Power, Rockford, Illinois 61109 USA.

As seen in reference to Fig. 5, the brace 66 provides a protective housing the for the reservoir 91, hydraulic pump 92, cylinder 80, hydraulic pump motor 94, associated hydraulic tubing 91, and electrical wiring and components used to operate the lift. An optional access panel 112 may be

provided as indicated to facilitate service of the hydraulic and electrical components.

As best seen in reference to Figs. 2 and 6, an inner edge of respective brackets 66 and 68 are interconnected along an interior bracket wall by a rear frame member as seen here in the form of an inverted U-shaped channel member 114. The channel member 114 provides reinforcement to the frame members 62 and 64 and interconnects with braces 66 and 68 to provide support and rigidity to the boom.

Further, the interior channel defined by member 114 provides a protective conduit through which the hydraulic lines 91 extend and interconnect the pair of hydraulic cylinders 80.

The rear frame member 114 is additionally used to secure the lifting apparatus to the underlying frame of the truck. As best seen in reference to Figs. 7-10, the rear frame member 114 defines a pair of lower, integral plates 116. Desirably, each plate 116 is positioned above a corresponding longitudinal truck frame member 130. A plurality of apertures 131 are defined within each plate 116 and allow the plate to serve as a template for drilling into the bed (not illustrated in Figs. 7- 10) of the truck. As best seen in reference to Fig. 10, thread connectors seen here as bolts 133 are positioned within the apertures 131 along either edge of the truck frame member 130. A securing bar or strap 135 defines corresponding apertures for receiving a terminal end of bolts 133. Bolts 133, using conventional nuts and washers, are used to secure strap 135 to a lower frame member 130 of the truck. This attachment method forms a clamp member 134 which secures the lifting assembly directly to a truck frame member.

The clamp 134 attachment maintains the integrity of the truck frame member. No drilling or welding to

the truck frame member 130 is required. The resulting connection directs a large proportion of the boom load to the truck frame, permitting the boom to engage and transport heavier loads which would be precluded by an attachment made solely to the truck bed.

As seen in reference to Fig. 10, additional apertures may be present within plate 116. The additional apertures permit plate 116 to provide a template which may be used with a variety of truck manufacturers and models. The proper selection of apertures therefore allows the plate 116 to be used with a wide variety of standard truck designs.

In reference to Fig. 9, an alternative attachment mechanism is provided for securing the rear frame member 114 of the lifting assembly to the truck frame. As discussed above, plate 116 is integrally attached to rear frame member 114.

Plate 116 defines a plurality of apertures 231 which are adapted for receiving bolts 233 which pass through the truck bed (not pictured) and engage a mounting bracket 250. Bracket 250 defines a series of corresponding slots for receiving respective bolts 233. As illustrated, bracket 250 is positioned along an outside wall of truck frame 130. A lateral flange 252 of bracket 250 engages the exterior wall of truck frame 130. Flange apertures 254 are used to receive existing truck bolts 256 that are conventionally used to secure an existing rear bumper bracket 260 which is temporarily disengaged from truck bolts 256.

Following the insertion of flange portion 252 over truck bolts 256, the bumper bracket 260 is repositioned upon bolts 256. Again, this attachment mechanism maintains the original integrity of the truck frame member 130 as provided by the truck manufacturer.

The front frame components of the lifting apparatus may be secured to a lateral cross-member 136 which supports the pickup truck bed. As best seen in reference to Fig. 7, each foot 71 of the front frame upright 70 defines a plurality of apertures therethrough. Bolts 333 may be used to connect the plate 71 to lateral cross-member 136.

The overall design of the lifting apparatus and attachment is such that most of the stress is communicated through the support frame to the underlying longitudinal frame members of the truck.

Accordingly, the front frame corners bear substantially less stress and may therefore be secured to the lateral truck bed support 136 using conventional securing bolts.

The operation of the boom 30 is controlled by a pendant remote control 120 which plugs into a mated electrical receptacle 121 along a forward opening of brace 66. Solenoids (not shown) which control the operation of the winch and the hydraulic valves are in proximity to receptacle 21 and are positioned within the protected interior space 67 of bracket arm 66. The pendant control 120 is connected to a length of electrical cable to allow an operator to move and monitor the boom while in operation. The pendant control employs one switch for operating the winch drum and uses a second switch for controlling the direction of the boom travel. The pendant control provides a safety mechanism for the lifting apparatus which prevents the unauthorized use or tampering of the equipment.

Simple removal of the pendant control mechanism 120 will render the lifting apparatus inoperable.

Electrical wiring (not illustrated) required to operate the boom components reside within the tubular frame of the boom. This protective enclosure prevents damage to the electrical wiring

by maintaining the wiring in a protective enclosure.

The electrical components of the hoist are designed to operate directly from the battery of the vehicle. The battery power source simplifies installation of the lifting apparatus. Further, having a 12-volt power supply facilitates other uses of the lifting apparatus when installed on a non-motorized vehicle. For instance, the lifting apparatus could be supplied to the bed of a towable trailer. While a tow trailer typically lacks a separate power supply, the lifting apparatus may be provided with simple connectors to permit the connection to a 12-volt battery or equivalent power source.

It has been found useful to incorporate a thermal reset breaker within the electrical circuitry of the winch. The thermal breaker will allow the winch to lift the maximum rated capacity of 1,500 pounds (680 Kg). If loads are engaged which are beyond the design parameters of the lifting apparatus, the breaker limits the available current draw of the winch, thereby increasing the electrical load of the winch. Accordingly, when the breaker trips, the winch stops while a mechanical brake holds the load. After a several second delay, the circuit will be restored. In this fashion, the winch can always be operated to release any engaged load. However, the winch will not operate to lift loads greater than the rated capacity.

The lifting apparatus of the present invention is particularly well suited for use with a standard three-quarter or one ton pickup truck. However, flatbed trucks and various trailers are equally useful in conjunction with the present invention.

For instance, in a flatbed truck, the frame

elements and interconnective supports may be mounted flush to the bed of the truck. Likewise, a narrower boom may be provided by placing the lateral frame members along the interior of the wheel wells. In such an arrangement, the lateral support members may be mounted flush to the bed of the cargo area. In all of the various embodiments, the compact design of the lifting apparatus allows substantially the full storage and cargo dimensions of the vehicle to be used in a conventional manner.

When installed on a standard one ton pickup, the lifting apparatus provides an above ground lifting height of 12'10" (3.9 m.). The boom allows an article to be placed approximately 2 feet (61 cm.) beyond the open tailgate of the vehicle. In a preferred configuration, a width between the boom arms is 54-1/4" (138 cm.) and allows a 4-1/2'x 7' (1.37 x 2.13 m.) article to be lifted and placed within the cargo bed of the truck.

The boom 130 may also be used to engage a panel, cover, or dispenser to enable the lifting apparatus to operate as a dumping vehicle.

Preferably, the panel or dispenser which permits the dumping of material carried thereon is removable to allow the operator to vary the operating load of the lifting or dumping apparatus.

The components which make up the frame assemblies, support arms/brackets, and boom are provided from modular components which can be interchanged with a related part. The modular construction simplifies the manufacturing, shipment, and installation of the unit. The modular construction also simplifies switching the operative pneumatic and electrical controls from the left side of the vehicle to a right side of a vehicle where local custom places the driver's steering controls on the right side of a vehicle.

Although desired embodiments of the invention have been described using specific terms, materials, and methods, such description is for illustrative purposes only. The words used are words of description rather than of limitation. It is to be understood that changes and variations may be made by those of ordinary skill in the art without departing from the spirit and scope of the present invention which is set forth in the following claims. In addition, it should be understood that aspects of the various embodiments may be interchanged, both in whole or in part.