Portable worker safety frame

A portable worker safety frame provides many of the benefits of a loading dock while enhancing worker safety. In one implementation, the safety frame provides a walking surface of adjustable height that may be placed adjacent to an arbitrary work surface of a transportation vehicle. The safety frame can provide a walking platform that has a similar length as the cargo bed itself, yet is portable by such conventional means as the forks of a lift truck. The portable worker safety frame also provides an overhead safety rail to which each worker may attach a safety harness cord.

TECHNICAL FIELD

The subject matter presented herein relates generally to loading and securing cargo on vehicles of transportation, and more particularly to a portable worker safety frame.

BACKGROUND

Loading and securing cargo on hauling vehicles, such as flatbed trailers of semi-trucks can be hazardous for human workers. Statistically, getting onto the cargo bed of a hauling vehicle via built-in or separate ladders or steps causes a certain percentage of slips and falls. As the cargo bed fills up, there is less room for workers, for the workers' tools, and for materials for securing the load, such as tarps, wraps, and banding supplies. Less room on the cargo bed increases the chances of falling off the edge of the working surface. Besides falling down or falling off the edge of the hauling vehicle, workers can also fall off the cargo itself, while it is being fastened to the cargo bed. When securing a load with straps and bands, the straps and bands often fasten to the side of the vehicle's bed, necessitating a work position off to the side of the hauling vehicle.

Loading docks and fixed worker platforms provide a safe surface for accessing a hauling vehicle's cargo bed, but are generally expensive to build and cannot be moved. Thus, long flatbed trailers must maneuver to the side of a fixed platform, which may not be the same height as the actual work surface of the trailer. Since fixed platforms and loading docks are permanently anchored in the ground with cement and/or bolted to a building, they cannot be transported to a position where the hauling vehicle may be conveniently parked. Rather, the vehicle must be brought to the conventional fixed platform.

SUMMARY

A portable worker safety frame provides many of the benefits of a loading dock or fixed platform while enhancing worker safety. In one implementation, the safety frame provides a walking surface of adjustable height that may be placed adjacent to an arbitrary work surface, such as the cargo bed of a flatbed trailer, flatbed railroad car, or other transportation vehicle. The safety frame can provide a walking platform that has a similar length as the cargo bed itself, yet is portable by such conventional means as the fork of a lift truck. The portable worker safety frame also provides an overhead safety rail, which may be adjustable in height and horizontal displacement, to which each worker may attach a safety harness cord. The structure of the portable safety frame is designed to have a center of mass that allows lifting from one edge while also counterbalancing the weight of workers and loads when the safety frame is placed on the ground. The portable safety frame can accommodate additional built-in and moveable counterweights to stabilize the structure at various adjustable heights and horizontal displacements of the walking surface and the overhead safety rail.

Portable worker safety frames can improve product workflow and plant layout. Finished product can be stored in multiple places or spread out over a large area of the plant as the product to be loaded need not be moved to a conventional fixed loading structure. For shipping and workflow efficiency, a loading crew moves only the portable worker safety frame to the finished product being loaded onto a truck for shipment, rather than moving all the finished pieces to one fixed loading spot in the facility.

The portable worker safety frame gives a person on a truck a safe place to stand while the finished product is being loaded and also provides an escape route if the load collapses. Embodiments of the portable worker safety frame can hold multiple workers.

This summary section is not intended to give a full description of the portable worker safety frame, or to provide a list of features and elements. A detailed description of example embodiments of the portable worker safety frame follows.

DETAILED DESCRIPTION

Overview

This disclosure describes a portable worker safety frame. In its many implementations, the exemplary safety frame emulates immovable platform fixtures and loading docks that are permanently installed in the ground to provide a surface for human workers servicing a cargo load on the hauling bed of an adjacent transportation vehicle, such as a truck or train. The portable worker safety frames described herein provide comparable strength and stability as conventional immovable worker platforms and docks made primarily of concrete, anchored in the ground, and/or bolted to the side of a building. Examples of the innovative portable worker safety frame described herein derive strength and stability from their structure and in some cases from counterweight systems, and not primarily from a permanent attachment to ground or a building. Thus, the portable worker safety frames are easily movable with commonly available means, such as a forklift vehicle, a lightweight crane, or in some cases, a palette jack; or in a variation, by onboard means, such as wheels and motor.

Portable worker safety frames can improve product workflow and plant layout. For example, utilizing a portable worker safety frame allows a producer to store finished product in multiple areas of the plant or spread out over a large area. This is not cost effective with a conventional fixed loading structure, as the finished product to be loaded must eventually be moved to the usually narrow confines of the fixed loading structure.

From the standpoint of workflow efficiency, streamlining, and safety, a shipping crew that uses the portable worker safety frame moves only one item—the portable worker safety frame—near to the finished product that is being loaded onto a truck for shipment, rather than the other way around, in which all of the finished pieces must be moved from their place of manufacture to the one fixed loading spot in the facility.

Besides their portability, embodiments of the portable worker safety frame include additional desirable features, such as an overhead safety rail for harnessing workers in order to provide protection from falls. The portable worker safety frame gives a person on a truck a safe place to stand while the finished product is being loaded and also provides an escape route if the load collapses. Moreover, embodiments of the portable worker safety frame can hold multiple workers.

An exemplary portable worker safety frame may also exploit construction materials to provide even greater lightness than that provided by structural design alone, yet with comparable load strength. The lightness and strength are complemented by adjustability. Embodiments of the portable worker safety frame allow personnel to work up the load at various heights whereas a loading dock typically only allows a fixed work height of 4′-0″ above a concrete floor.

The portable worker safety frame can be moved from the side of one vehicle to the side of a next vehicle within a facility, e.g., among numerous truck-and-trailer combinations, rather than having to jockey long trucks or other hauling vehicles to the fixed position of an immovable service platform. Further, a single instance of the portable worker safety frame can be moved to service multiple vehicles within a facility that has limited physical area, rather than having to move every vehicle or build multiple fixed docks to provide the same benefit. Being portable, the portable worker safety frame can also be moved between facilities. That is, in some implementations, the portable worker safety frame can itself be loaded on a transportation vehicle and transferred to another site.

Exemplary Portable Worker Safety Frames

FIG. 1shows one implementation of the portable worker safety frame100. A base assembly102(“stand”) includes a base frame104for establishing a stable support of the entire safety frame100on a ground surface. The base assembly102also includes upright support members106secured to the base frame104, and sleeves108, at least some of which are secured near an edge of the base frame104for receiving the tines110of a lift truck112, such as a forklift vehicle.

A walking platform114with walking surface115is secured to the upright support members106, allowing human workers116to service cargo118being loaded on an arbitrary work surface120adjacent to the walking platform114, such as the bed of a flatbed trailer122. The length of the walking platform114and/or of the portable worker safety frame100can be comparable to the length of the flatbed trailer122or other arbitrary work surface120.

An overhead safety rail assembly124is secured via horizontal members126to the upright support members106. The overhead safety rail assembly124includes an overhead safety rail127that provides an attachment point for support harness cords128used by human workers116on the work surface120.

In one implementation, the base frame104has a first longitudinal support member130and coplanar end members132to form an I-shaped support base or an H-shaped support base. Other implementations of the base frame104are described with respect to later Figures.

The illustrated portable worker safety frame100is built mainly of steel I-beams. Other construction materials may be used, however, such as aluminum or aluminum-magnesium alloys, for lighter weight. The walking surface115may be made of steel grate, expanded steel mesh, or other suitable materials, that preferably provide a sturdy, non-slip surface.

Besides longitudinal support member130, a second “massive” longitudinal support member134is secured on the lifting side of the portable worker safety frame100. The second longitudinal support member134adds structural integrity to the base frame104and is intentionally selected to have a high mass relative to its structural support function, in order to provide a counterweight for stabilizing the safety frame100. The second longitudinal support member134counterbalances the walking platform114and the overhead safety rail assembly124when these are under load from cargo118and multiple workers116.

FIG. 2shows another implementation of the portable worker safety frame100′. The primary difference between the example safety frame100ofFIG. 1and the example safety frame100′ ofFIG. 2is that the first longitudinal support member130of the base frame104inFIG. 1is formed of an I-beam, while the first longitudinal support member202inFIG. 2is of a hollow, built-up beam construction. The structure of the base frame204inFIG. 2can provide lighter weight of the entire safety frame100′ while providing comparable strength as the embodiment shown inFIG. 1.

InFIG. 2, the height of the walking platform114is adjustable. The height of the overhead safety rail127is also adjustable. Further, the horizontal position of the overhead safety rail127is also adjustable (not shown inFIG. 2) to accommodate arbitrary work surfaces of various widths.

The base frame204(or104inFIG. 1) may have adjustable feet206to level the portable worker safety frame100′ on an uneven ground surface.

As shown inFIG. 3(A), when placed on a ground surface, the ground provides support302through the members contacting the ground or through adjustable feet206used with the base frame204. The structure of the base frame204, in turn, provides strength for supporting the weight306of workers116(such as inFIGS. 1 and 2, the workers116who may be on the walking platform114and workers116who may be attached to the overhead safety rail assembly124). InFIG. 3(B), conversely, when the portable worker safety frame100′ is being lifted by the lift truck112, the base frame204possesses a rigidity for maintaining the shape and structural integrity of the portable worker safety frame100′ along the span of its entire length when the safety frame structure100′ is supported only by the sleeves108, i.e., when the support310for lifting the entire safety frame100′ is applied only at the lifting sleeves108.

FIG. 4depicts a center of mass400of one embodiment of the portable worker safety frame100. The structural configuration of the portable safety frame100includes (or allows for) counterweight on the opposite side of the horizontal extension of the overhead safety rail assembly124and walking platform114. For example, the massive longitudinal support member134is included in some embodiments to shift the center of mass400away from the horizontal extension of the overhead safety rail assembly124vehicle side of the walking platform114. Having a structure in which the center of mass400is shifted in an opposite direction from weight-bearing horizontal extensions enables the base frame104to counterbalance the weight of a variable number of workers on the walking platform114who (potentially) may become a load on the overhead safety rail assembly124. During a mishap, it is assumed that the overhead safety rail assembly124will potentially be bearing the weight of some or all workers116engaged on the portable worker safety frame100.

From another perspective, the shifted center of mass400as just described, is also positioned nearer a lifting edge of the base frame104, and centered between the sleeves108, enabling some implementations of the portable worker safety frame100to be lifted more easily at the lifting edge, and also making it possible for very large implementations of the portable worker safety frame100that could not otherwise be reasonably handled, to be lifted by relatively small, standard forklift trucks. Thus, in one embodiment the portable worker safety frame100uses the massive longitudinal support member134to shift the center of mass400of the portable worker safety frame100toward the lifting side to assist transportation and provide counterbalance for safety.

FIG. 5shows another embodiment of the portable worker safety frame100that accepts portable counterweights500as an alternative to (or in addition to) the massive longitudinal support member134of other embodiments. The counterweights can be made of concrete, lead, zinc, gravel-filled containers, etc. In one implementation, a 400-500 kilogram (or half-ton) counterweight500is placed on the base frame104at each of two (or more) upright support members106. When the particular embodiment of the portable worker safety frame100does not have an adjustable walking platform114or an adjustable overhead safety rail assembly124(i.e., when these are fixed) then fixed counterweights500of fixed mass can be used safely. In many implementations, counterweights500of such fixed size suffice. However, in larger implementations of the portable worker safety frame100, or in implementations in which the walking platform114and the overhead safety rail assembly124are adjustable over a wide range of height and horizontal displacement settings, then variable counterweight schemes are employed, as described below.

FIG. 6shows an embodiment of the base assembly102in which three upright support members106, instead of two, provide stability for a relatively long embodiment of the portable worker safety frame100. In this embodiment, the upright support members106have multiple fastening positions602at which the walking platform114and the overhead safety rail assembly124can be temporarily secured, providing height adjustments for the walking platform114and/or the overhead safety rail assembly124. For example, in one implementation, an upper part of the upright support member106may slide inside a lower part of the upright support member106to provide vertical adjustment, as shown inFIG. 2.

FIG. 7(A)shows an adjustable implementation of the portable worker safety frame100in an unexpanded state.FIG. 7(B)shows the portable worker safety frame100in an expanded state. In the illustration ofFIG. 7(B), the darkened segments of the upright support members106and the darkened segment of the horizontal members126of the overhead safety rail assembly124show possible locations for sliding adjustments.

In some implementations, adjusting the height and/or the horizontal displacement of the walking platform114and the overhead safety rail assembly124can increase a tipping tendency of the portable worker safety frame100. That is, extension of the upright support members106and the horizontal members126increases a torque force vector acting to rotate the portable worker safety frame100at the axis702where the upright support members106attach to the base frame104. The magnitude of the torque vector depends on the weight of the workers, and any cargo load that may be temporarily on the walking platform114, multiplied by the length of the lever arm radius (i.e., the extended length) of the upright support members106. That is, in some embodiments, when the adjustments are extended and there are workers116and cargo118on the portable worker safety frame100, a correspondingly greater counterweight500may be used to provide stability. Alternatively, the base frame104may also be extendible704to provide a longer counterbalancing lever arm at the base frame104that uses a counterweight500of constant mass. Other means of extending a fixed onboard counterweight to provide counterbalancing may also be used, such as a folding arm on the base frame104that extends the counterweight500but which may be folded up for transport; or a cranked worm screw that slides the counterweight500via a threaded hole in the counterweight500, etc.

FIG. 8shows an extendible embodiment of the portable worker safety frame in which indicators802,804, and806display the amount of counterweight to use, or alternatively, display an amount of recommended base frame extension704with a fixed counterweight500.

In one implementation, the indicators802,804, and806each show progressive counterweight masses (or “sizes”). The mass values are revealed by the sliding parts as the associated members of the safety frame100are extended further and further. In this implementation, the indicators802,804, and806each show a separate counterweight mass recommended as a minimum total counterweight mass for the entire portable worker safety frame100. Thus, whichever displayed mass value is greatest is the amount of counterweight500recommended for the entire safety frame100. So, each adjustment of the walking platform height, the overhead safety rail height, or the overhead safety rail horizontal displacement indicates a corresponding total counterweight size to place on the base frame104. In a variation, the amount of counterweight recommended is per worker using the frame.

In another implementation, as the members of the portable worker safety frame100are extended, the indicators802,804, and806progressively display respective multipliers, such that the three values indicated are multiplied to obtain a recommended counterweight setting. In yet another implementation, the indicators802,804, and806progressively display respective counterweight values that are added together to obtain a recommended total counterweight value. The indications of recommended total counterweight, counterweight per worker/load, or base frame extension704to increase the counterbalancing lever arm of the base frame104can also be displayed by the indicators802,804, and806via a color coding scheme.

FIG. 9shows an alternate embodiment of the portable worker safety frame900in which onboard wheels (motor, etc.) are added to the structure so that the portable worker safety frame900can be moved without a lift truck, or even self-propelled. Wheels, castors (not shown), and other rolling devices may be appropriate for smaller versions of the safety frame900. Versions of the safety frame100may also be lifted by crane or other mechanism, in which case the lifting sleeves108may be replaced by a hook or other lifting point.

Conclusion