1. Field of the Invention
The invention relates generally to a crane hook assembly for lifting heavy, elongated loads and to methods for safely lifting such loads. Particularly, the present invention relates to a specialized crane hook assembly for lifting the elongated, heavy sections, which when assembled form the high support tower for a wind powered electrical generator.
2. Description of the Related Art
Wind powered generators are mounted at the top of high support towers that are commonly over two hundred feet high so as to catch the high surface winds. The towers are installed in open country, usually far distant from heavily populated areas, and all the components of the generator and tower must be transported to the site by rail or large truck and there unloaded by cranes equipped for the unloading process. A large, high capacity generator unit is typically mounted on the top of such a tower, approximately 240 feet above ground level. The typical tower is formed from three long cylindrical tower sections, each section having a length of about 82 feet. The lowest section is quite massive with a fourteen foot diameter and can weigh about eighty tons. The middle section is slightly less in weight and has some taper from bottom to top. The upper section tapers further to a final diameter of about 9 feet at its upper end. Typically, each tower section has an annular mounting flange at each end, with the flange extending radially inwardly and outwardly from the cylindrical tower section wall at a right angle to the tower section's central longitudinal axis. Each annular flange has a multiplicity of bolt apertures positioned about its outer perimeter, and these apertures align with the apertures of an adjoining tower section's flange to allow adjacent tower sections to be bolted together end-to-end when the tower is erected at the construction site.
Each of the three tower sections is transported to the tower construction site on separate semi-trucks or rail cars, and the sections are delivered on a rigorous schedule which assures that all the trucks or rail cars will be available for prompt unloading so the trucks or rail cars can return at once to normal service. Because of their great size, it is usually necessary to lift each of the tower sections from the truck bed or rail car using two separate cranes, one being positioned at each end of the tower section.
Previous devices and methods for lifting and unloading the tower sections have utilized steel or nylon web slings positioned around the outer periphery of the tower section near each end of the tower. Another known hook assembly utilizes a pair of crane hook assemblies, wherein a hook assembly is bolted to the flanges at each end of the tower section using a multiplicity of bolts and nuts so as to provide a relatively fail safe engagement. Additional known crane hook assemblies were developed with structure which engaged the inner circumference of the annular flange at each end of the tower section.
The present invention addresses limitations associated with the prior art.
The present invention provides a crane hook assembly and method of use for static lifting of large, heavy conduits, such as wind generator tower sections. The crane hook assembly of the present invention can be used to more safely lift such tower sections and to do so without scratching or damaging areas of the tower section that will be visible once the tower is assembled.
The preferred crane hook assembly includes an extremely heavy, rigid, upright, steel frame member which has an attachment aperture that can be used to connect the crane hook assembly to a crane. The crane hook assembly additionally includes a forwardly extending support member positioned at the bottom of the front face of the frame member. The support member cooperates with the frame member to engage and retain an annular flange of the tower section. The crane hook assembly is safely secured onto the tower section with a securing mechanism, preferably utilizing a rack and pinion gear assembly for actuating a locking pin. The sliding, retractable, locking pin may be actuated such that the locking pin is movable between a locking position, wherein the locking pin is positioned horizontally over the tower section flange, and an unlocked position, wherein the locking pin is fully retracted from the front face. Because the locking pin can be fully retracted from the front face, an unobstructed entry zone can be formed such that the tower section can easily be positioned within the entry zone without damaging visible areas of the tower section.
Preferably, to use the crane hook assembly of the present invention for a static lift of a tower segment, the crane hook assembly is first shackled to a crane through the attachment aperture, and then the crane hook assembly is positioned with the front face of the frame member bearing against the flat outer surface of the annular flange at each end of the tower section. During this positioning, the support member partially extends within the open end of the tower section such that the annular flange slips between the front face of the frame member and the support member when the crane hook assembly is raised. This positioning may be performed without the need for human hands to be in close physical proximity to the crane hook assembly, which greatly increases the safety of the process as compared to known devices.
Then, to secure the crane hook assembly to the tower section, the locking pin is actuated by an operator standing on the ground and away from the tower section and hook. Preferably, the operator uses an elongated wrench to move the locking pin outwardly from the frame member to position it over the circular outer edge of the annular flange of the tower section to secure the tower section to the crane hook assembly and preventing it from inadvertently slipping therefrom. It should also be noted that during this lifting process, only the inner circumference and mating face of the annular flange of the tower section is in contact with the crane hook assembly, and thus if any scratching of the tower flange occurs, such scratching will be applied only to parts of the flange that are inside the tower and will not be visible when the tower is erected.
These and various other advantages and features of novelty which characterize the present invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the present invention.
The preferred embodiments of the present invention are illustrated in
Now referring to
As best shown in
The crane hook assembly 10 can be secured to the tower section 110 with a securing mechanism 60, preferably a rack and pinion gear assembly, as best illustrated in
As shown, the rack and pinion gear assembly 60 includes a rotatably mounted pinion 62 encased by a housing 68 and a preferably cylindrical cross section locking pin 80 having first and second ends 84, 86 and a rack 88 therebetween. The housing 68 is positioned on the rear surface 16 of the frame member 12 and, in preferred embodiments, includes a lock pin guide 72 extending along the length of the housing to slideably support the locking pin 80. The preferred housing 68 additionally includes protective piping 76 to protect grease fittings 78.
The pinion 62 has a set of pinion teeth 64 that engage a second set of teeth 90 positioned along the length of the rack 88. As the pinion 62 rotates, the pinion teeth 64 engage the rack teeth 90 and correspondingly move the locking pin 80 horizontally. The sliding, retractable, locking pin 80 may be positioned in either a locked or load carrying position 85, wherein the locking pin 80 is positioned over the flange 116a, 116b and an unlocked position 83, wherein the locking pin 80 is fully retracted into the front surface 14. In preferred embodiments, the rack and pinion gear assembly 60 includes a downwardly facing actuator 92, the actuator 92 controlling the movement of the pinion teeth 64.
Many known devices for moving large conduits, such as steel or nylon web slings, cause serious scratching and marring of the exterior surface and paint on the tower section and created further refinishing expense and delays in erecting the tower while the surface was refinished. This touch-up work is time consuming, difficult and costly since the refinishing work is often located on portions of the large diameter sections up to fourteen feet off the ground and in other cases on portions which are marginally accessible without moving the heavy sections. The crane hook assembly of the present invention eliminates damage to visible surfaces of the tower section when the crane hook assembly is used properly. One of the damage prevention features includes the locking pin 80 being fully retractable so that it does not protrude from the front surface 14. When the locking pin 80 is fully retracted, an unobstructed entry zone is formed such that the crane hook assembly 10 can be brought to the tower section 110 and the tower flange received into the unobstructed entry zone without the scratching or damaging of visible surfaces of the tower section. The preferred unobstructed entry zone includes a volume between a generally flat portion 15 of the front surface 14 and retention barrier 44 which extends from the top of the support member 40 to the shackle aperture 22 when the locking pin 80 is fully retracted. To aid in aligning the tower section 110 within the entry zone, the preferred rear surface 16 of the frame member 12 includes one attachment element 17 proximate each support stand 26. A rope 19 can be secured to each of the attachment elements 17, respectively, so that additional operators O′ can assist in the lateral movement of the crane hook assembly 10 during the tower attachment process (see, in particular,
Now referring, in particular to
Referring now to
In the most preferred embodiments, the elongated wrench 94 further includes a funnel-shaped guide 100 proximate the socket 95 to increase the ease in which the socket 95 be operatively connected to the actuator 92. The preferred funnel shaped guide 100 is secured to or integrally formed with the crank shaft 96 or the socket 95 such that the operator O can easily align the socket 95 with the actuator 92 without risk of the funnel shaped guide 100 falling off the crank shaft 96. The socket 95 and actuator 92 can, for example, have a hexagonal, square or triangular shape. The shape of the socket 95 corresponds to the shape of the actuator 92 such that the actuator 92 can be engaged and operatively adjusted by engaging the socket 95 with the actuator 92 and rotating the socket such that the actuator correspondingly rotates.
Referring now to
Referring now in particular to
As the crane hook assembly 10 is raised by the crane C, the circular inner circumference 120a, 120b of the annular flange 116a-b contacts and bears against the shafts 46. This alignment can be established without the need for human hands to physically contact the crane hook assembly 10, which further increases the safety of the process.
To secure the crane hook assembly 10 in place, the locking pin 80 is then actuated by the main operator O, preferably with an elongated wrench 94, to move the locking pin 80 outwardly from the front surface 14 to locked position 85 over the circular outer edge 118a, 118b of the annular flange 116a, 116b of the tower section 110, securing the tower section 110 to the crane hook assembly 10 and preventing it from inadvertently slipping therefrom. In preferred embodiments, the locking pin 80 is configured and arranged such that in locked position it will be spaced about one inch above the outer edge 118a, 118b of the annular flange 116a, 116b when in a locking position and the support member 40 is preferably arranged and configured to have a span S such that there is at least about 0.5-1.0 inch clearance on both sides of the annular flange 116a, 116b. It should be noted that during this lifting process, only the circular inner edge 120a, 120b of the annular flange 116a, 116b is in contact with the crane hook assembly 10, and thus, if any scratching of the annular flange occurs, such scratching will be applied only to parts of the annular flange that are inside the tower and will not be visible when the tower is erected.
In order to safely secure the tower section flange 116a, 116b to the crane hook assembly, the securing mechanism 60 must be arranged and configured such that the locking pin 80 will prevent the tower section flange 116a, 116b from disengaging from the crane hook assembly 10 while in the secured position while still clearing the tower section flange 116a, 116b to prevent damage to the visible surfaces under normal operating conditions. As further illustrated in
Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims.
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Number | Date | Country | |
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20090108604 A1 | Apr 2009 | US |