The present invention relates generally to hoist and/or crane systems. More particularly, the present invention relates to a portable or mobile system which can be utilized to hoist or lift materials.
Hoist systems and cranes are used in a variety of applications for lifting a variety of materials. Construction sites often use hoists and cranes to lift building materials and the like. Another application relates to the lifting of signs and the installation of advertising copy at billboard sites. Advertising copy can include images placed primarily on vinyl films or wood. Wood is often used for extensions or cut-outs which extend above or beyond the typical rectangular-shaped billboard.
In the billboard industry, billboards are comprised of a billboard structure and faces. The faces are mounted on an area on the billboard structure where advertising copy is typically displayed. Advertising copy includes graphics, images, or text, and is usually placed on vinyl film or wood. The advertising copy can be changed when it is desirable to change the message or advertisement on the billboard. Alternatively, the billboard can utilize paper, cardboard, wood, plastic film, or other materials as the surface for holding the images which are attached to the face of the billboard.
Heretofore, the advertising copy was lifted onto the billboard faces manually, either by pulling a rope up by hand (roping), by utilizing generic block and tackle, or with the assistance of a crane truck. Roping can be strenuous and tiring, and requires younger, stronger people to perform this task on a regular and continuing basis. Utilizing generic block and tackle requires extensive set-up time and can require more than one person. Further, generic block and tackle is not well suited to the positioning requirements associated with advertising copy replacement on a billboard structure.
Crane trucks are relatively expensive pieces of equipment. Further, the use of a crane truck requires that the operating area surrounding the billboard be clear of obstacles, power lines, etc. Billboard structures are frequently located in remote areas or areas which are difficult to access. For example, billboard structures that are located in farmer fields, railroad right-of-ways, junkyards, parking lots, snowed-in areas, etc. are often difficult to access with a large piece of equipment.
U.S. patent application publication U.S. 2001/0050263A1 discloses a portable aluminum jib crane with an attached nip roller drive system for lifting billboard vinyls. The nip roller drive system utilizes two rollers to raise and lower a flat rope. The drive roller assembly is mounted upon a subframe comprised of two square tubing members. The square tubing members can be mounted in a female square tubing member which is attached to a trolley. The trolley can be configured to ride on an I-beam associated with the billboard structure.
Heretofore, hoist systems for billboards have been complicated and heavy, requiring more than one person or the use of equipment to bring the hoist system to the top of the billboard structure. Further, such systems have been difficult to mount onto the billboard structure. Billboard structures vary in size and requires a mounting system which can adapt to the various types of billboard structures. Moreover, such systems have been electrically conductive, making it more dangerous for a person to utilize the system.
Thus, there is a need for a hoist system which is portable and lightweight. Further, there is a need for a hoist system which can be easily mounted on a variety of billboard structures. Further still, there is a need for a hoist system which is manufactured from relatively lightweight components. Yet further, there is a need for a low-cost hoist system. Even further still, there is a need for a hoist system optimized for the replacement of advertising copy. Still further, there is a need for an electrically non-conductive hoist system.
An exemplary embodiment relates to a lightweight hoist system for raising an article. The hoist system includes a composite pole member having a bend, a mounting structure attachable to the composite pole member and attachable to a billboard structure, and a winch assembly. The winch assembly is attached to the pole. The winch assembly is capable of winding a flexible line.
Another exemplary embodiment relates to a pole member for a hoist system. The hoist system is for raising items such as vinyls, extensions, equipment or tools when installing advertising copy on the faces of billboards. The pole member includes a composite material having fibers. The fibers are wound at an angle or a combination of angles. The pole member has a first end and a second end and is bent at a location between the first end and the second end.
Still another exemplary embodiment relates to a mounting structure for securing a pole member of a hoist system to a billboard structure. The mounting structure includes a first bearing for securing the pole member at or near a first end and a second bearing for securing the pole member at a point closer to a second end of the pole member than the first bearing. The second end is opposite the first end. The mounting structure also includes a frame which can be variably coupled to the billboard structure.
Yet another embodiment relates to a lightweight hoist system for raising an article. The hoist system includes a composite pole member, a mounting structure and a winch assembly. The composite pole member includes a ring bearing for engaging the mounting structure.
The exemplary embodiments will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements in the various drawings, and:
With reference to
Various features of hoist system 10 contribute to its advantageous use in a variety of applications and environments. The combination of mounting structure 14, bearing 42, pole member 12, and winch assembly 16 provides significant advantages for certain applications. Although discussed below with respect to raising billboard vinyls and other signage, hoist system 10 can be utilized in other applications where lightweight equipment for lifting articles is advantageous.
Hoist system 10 is preferably a lightweight system that can be operated and installed by a single person. Hoist system 10 can be utilized to lift loads less than 250 pounds, although the description of hoist system 10 is not limited to such a rating.
Winch assembly 16 is preferably attached to a center portion 18 of pole element or member 12. Center portion 18 is between a bottom end 22 and a top end 24 of pole element or member 12. Pole member 12 is preferably rotatable with respect to mounting structure 14 so that vinyls and other signage can be moved across the face of the billboard as necessary.
Winch assembly 16 is fixed with respect to pole member 12 and is used to raise and lower a line 28 to manipulate vinyls or other signage on a billboard structure. Pole member 12 is bent to enable positioning of the vinyls or other signage and to provide appropriate clearance as vinyls or other signage are raised and lowered. Hoist system 10 allows vinyls or other signage to be rotated up to 360 degrees.
Winch assembly 16 includes a pulley 26 attached at top end 24 of pole element 12 and a crank assembly 19 attached at center portion 18. A clamping bracket or other hardware can be used to attach winch assembly 16 to pole member 12. Any number of block and tackle or other bearings can be utilized with winch assembly 16. Preferably, winch assembly 16 can be driven by a portable electric drill. Alternatively, assembly 16 can include a crank or can otherwise be manipulated manually to wind and unwind line 28. Line 28 can include a hook or other attachment device 32.
Attachment device 32 can engage a tube upon which a vinyl is rolled. The vinyl can be unrolled from the tube when it is installed on the billboard structure. Attachment device 32 can include a rotatable joint which allows the vinyl to be handled more easily. In an application which uses bundled vinyls, attachment device 32 can engage a strap that is wrapped around the bundle. Attachment device 32 can also engage a carabiner. Other equipment, tools, extensions, cut-outs, etc. can be raised by hoist system 10. Advantageously, hoist system 10 is capable of raising cut-outs and extensions above the top of the billboard structure due to the height of pole member 12.
Preferably, line 28 is a one-eighth inch or 7×19 galvanized or stainless steel wire rope with a breaking strength of at least 2,000 pounds, or a one-eighth inch stranded synthetic rope with a breaking strength of at least 2,000 pounds for non-metallic applications. Alternatively, line 28 can be a flat belt, a nylon cord, a chain, a rope, or a cable. Pulley 26 is preferably a fixed block with a two-inch or larger sheave size to handle line 28.
Winch assembly 16 can be operated via a portable electric hand drill (cordless DC or corded AC). Preferably, an electric one-half inch drill, such as those manufactured by Milwaukee Electric Tool Corporation of Wisconsin, can be utilized to drive winch assembly 16. Advantageously, the portable hand drill is easy to transport up to the billboard structure and does not need to remain on the billboard structure (as a fixed motor unit does) where it is exposed to the environment. Alternatively, winch assembly 16 can include an electric motor coupled to a battery or an AC power source.
Winch assembly 16 is preferably operable from either side and includes a braking system. Operation from either side is particularly advantageous as pole member 12 is rotated, and is achieved by applying the power source to either end of the drive shaft. The drive shaft extends from winch assembly 16 in opposite directions on both sides to permit engagement from either side.
Access on either side of winch assembly 16 is important due to the narrow walkway associated with the typical billboard structure. The ability to drive winch assembly 16 from either side allows safe and effective operation as pole member 12 is rotated and vinyls and other signage are moved across the face of the billboard structure. Winch assembly 16 can be a winch system such as a DLB1550 Winch manufactured by Dutton-Laison Company of Hastings, Nebr. Alternative crank mechanisms, ratchet systems or winch devices can be utilized.
Pole member 12 is shown in
Top plate assembly 40 engages bearing 42. Preferably, bearing 42 is a polymer (such as nylon) bearing ring or hold ring slid about the circumference of pole member 12. Bearing 42 can slide within a slot 44 of top plate assembly 40 as pole member 12 is raised. A rubber cushion mount ring devices with a three-inch diameter or other mechanical stop can be used to prevent bearing 42 from sliding off of pole member 12. Top plate assembly 40 can be comprised of two plates welded together to define a channel or slot 44.
Mounting structure 14 can be attached to a billboard structure by welding or with clamps, bolts, nuts or other mechanical fastening devices. Advantageously, pole member 12 can be rotated on bearing 38 to various positions to ease the loading and unloading of materials, such as advertising copy, tri-vision slats, vinyls, extensions, equipment or tools on the billboard structure.
With reference to
Exemplary dimensions for pole member 12 are given below. Pole member 12 preferably has an outside diameter of 3.5 inches and an inside diameter of 3.0 inches. Section 56 preferably has an arc length of 59 inches. Section 52 is disposed at a 37 degree angle with respect to section 54 and pole member 12 has a total length of 13 feet. Preferably, section 56 has a radius of 91.0 inches, and sections 52 and 54 have lengths of 37 and 60 inches, respectively. Alternatively, section 52 can be at an angle between 30 and 45 degrees with respect to section 54.
Advantageously, pole member 12 is manufactured from a composite material. In a preferred embodiment, pole member 12 is a single unitary piece having fibers placed or wound at angles in a range from 0 to 90 degrees. In one embodiment, pole member 12 includes fibers wound at an angle or combination of angles between 10 and 88 degrees. The fibers can be continuous fibers.
Applicants have found that a winding angle of approximately 35 degrees (e.g., 30–40 degrees) enables the formation of bent section 56 in accordance with the design criteria and application parameters associated with billboard hoist applications. In particular, a winding angle of approximately 35 degrees (e.g., 30–45 degrees) allows bent section 56 to be created so that section 52 is at a 37 degree angle (e.g., 1–90 degrees, more preferably 30–45 degrees) with respect to section 54. Embodiments of pole member 12 are not limited to the exemplary dimensions and angles given above unless expressly recited in the claims.
Pole member 12 is preferably a filament wound glass fiber composite pole having a high specific strength (e.g., approximately eight times stainless steel) and a very light weight (e.g., approximately one-fourth the weight of steel). Pole member 12 is preferably manufactured from an electrically non-conductive substance and is not subject to corrosion or affected by outdoor exposure. Therefore, the composite material provides a high strength, lightweight, long life, weather resistant, non-conductive pole member 12.
Although a continuous fiber filament winding is the preferred manufacturing process for pole member 12, other manufacturing processes could be used such as pultrusion, filament placement, centrifugal casting, tape placement, braiding, etc. Although the preferred reinforcing material is fiberglass fibers, other reinforcing fibers could be used, such as graphite/carbon fibers, aramid/Kevlar® fibers, polypropylene fibers, polyester fibers, nylon fibers, boron fibers, etc. The fibers can be long fibers or continuous fibers.
Although epoxy resin with an anhydride promoter or curing agent is the preferred resin or matrix system, other thermoset resins such as polyester, vinylester, etc. could be used with appropriate promoters. Some thermoplastic resin systems could also be used. Prepreg fibers, which are fibers that have been pre-impregnated with a resin system, could also be used as the material of choice for pole member 12. Additives such as ultraviolet light absorbers, colorants, catalysts and the like can be employed in manufacturing pole member 12.
The tensile strength of the continuous fiber-resin matrix composite material of pole member 12 is advantageously high for its weight. Theoretically, the maximum tensile strength properties are achieved when the fiber alignment matches the direction of the imposed load. Assuming the length of pole member 12 to be the axis, maximum tensile strength of pole member 12 would have the fibers lay along the axis (or at a 0 degree angle to the axis). The actual (practical) angle of lay will be influenced by the manufacturing process. Composite pultrusion will permit a 0 degree lay angle. Filament winding will not necessarily permit a 0 degree lay angle.
A preferred manufacturing process for pole member 12 is filament winding; it is a cost efficient process to achieve an optimum weight pole member 12 with a selection (or combination) of wind angles to meet strength and durability requirements. If pole member 12 is to be bent in one piece (the preferred method), the wind angle(s) chosen may produce a pole member 12 that has less than maximum strength to permit the bending operation to occur using the preferred method, which is to start with a straight filament wound part and perform the bend in a secondary operation. The winding could be performed on a bent mandrel, but this method can result in higher tooling and handling costs.
In another embodiment, the optimum and preferred winding angles for an exemplary pole member 12 are between 15 to 70 degrees. Higher winding angles could theoretically be used but the thickness and weight of pole member 12 would be greater than the part produced with the optimum winding angles or combination of winding angles. The weight fraction of the reinforcing glass fibers in the resin can be 45–90 percent.
In an alternative embodiment in
In another embodiment, bent section 56 can be reinforced with windings over the outside circumference of member 12. Alternatively, or in addition, additional windings can be provided on the inside of section 56 for reinforcement.
Due to the lightweight construction of pole member 12 (e.g., in a preferred embodiment of composite material construction), pole member 12 can be lifted by a single person to the top of a billboard and does not require additional crane materials or boom trucks. Further, the non-metallic material associated with pole member 12 reduces risks associated with lightning and power lines. The material associated with pole member 12 is also advantageously impact resistant and has a safe failure mode where pole member 12 has an observable, localized, progressive failure mode of the fiber and resin system but will not completely sever during failure under design load levels.
With reference to
With reference to
Channels 58 allow adequate structural support in the unique and variable conditions associated with billboard structures. Channels 58 provide a structurally sound mounting assembly for 360 degree operation.
With reference to
Alternatively, bearing 38 can be a cylindrical member or a bracket for holding pole member 12 to mounting structure 14. In one embodiment, bearing 38 is a composite or plastic cylindrical member which fits within section 54 or around section 54.
With reference to
In
Once bearing 42 engages slot 44, both pins 92 are slid through apertures 68 (
The at least somewhat spherical shape of mounting ball 38 allows a single person to set pole member 12 over mounting ball 38 and slowly bring it into engagement, thereby easing the placement of pole member 12 so that one person can assemble hoist system 10. Alternative mounting hardware can be utilized without departing from the scope of the invention.
In one embodiment, hoist system 10 can be permanently attached to the billboard structure, requiring that an operator merely bring a portable electric hand drill to raise and lower line 28. Preferably, top attachments for mounting structure 14 are at least 36 inches above the base of the structure and at least 30 inches above the location of the lower attachments. Alternatively, mounting structure 14 can be welded to the billboard structure. Channel extensions can be attached to channels 58 if necessary.
In another embodiment, two mounting structure assemblies 14 are employed on a single billboard structure. If two assemblies 14 are utilized at opposite ends of the billboard structure, a single pole assembly (pole member 12, bearing 42, and winch assembly 16) can be used to handle vinyls that are rolled in a uniform direction.
After installation of vinyls, hoist system 10 can be disassembled and the pole assembly strapped to the billboard structure for storage. Pole member 12 should be strapped or bracketed at section 56, with end 22 resting on the bottom of the catwalk.
It is understood that although the detailed drawings, specific examples, materials and particular values given provide exemplary embodiments of the present invention, the exemplary embodiments are for the purpose of illustration only. The method and apparatus in the aforementioned embodiments are not limited to the precise details and descriptions disclosed. For example, although particular mounting positions are described, other mounting structures can be utilized. Various changes may be made to the details disclosed without departing from the scope of the invention which is defined by the following claims.
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