This application relates to hooks used in lifting loads, and in particular, to remote controlled hooks used in lifting and maneuvering heavy loads.
Hooks used in lifting applications for general construction, fishing, logging, cargo handling, foundry work and other industries, are known. In some situations, there are advantages to providing a hook that can be controlled remotely, e.g., so as not to require an operator to directly handle the hook during one or more of the steps associated with a lifting operation. Examples of remote controlled hooks are described in commonly owned U.S. Pat. No. 4,095,833, U.S. Pat. No. 4,193,627, and U.S. Pat. No. 4,530,535, which are incorporated herein by this reference.
One common lifting application is cargo handling, which includes the lifting of cargo into and out of ships using a crane. Typically, hooks for lifting cargo are attached to strapping, webbing, wire and/or other type of slinging arrangement arranged around the cargo. The hooks may be used in groups that are suspended from a lifting frame and/or crane, usually by lifting chains. The hooks are engaged with the slings, usually by hand. Typically, the hooks are locked in a closed position, and the operator then engages the sling by passing it through to the throat of the hook, which may involve depressing a spring-loaded latch extending over the hook gap. It is also possible to lock the hook in place after the slings are received in the hook throat.
After the cargo is lifted and transported, it is desirable to release or unlock the hook remotely, preferably without requiring personnel to be in the direct area of the hooks to manually release them. Conventional cargo hooks are pneumatically controllable to be released or “unlocked” from the closed position to an open position in which the hook can freely pivot, and will usually be released from the sling without handling by an operator when the cable to which the hook is attached is raised. In some situations, conventional cargo hooks are configured to be unlocked for a predetermined time, and may automatically relock after that time. If the hooks relock while some or all of the slings are still in place within the throat of the hook, a second unlock cycle is necessary. If the crane operator remains unaware that the hooks have relocked and at least one of the slings is still attached, the current cargo may be jerked or moved unexpectedly when the operator attempts to move the hooks believed to be no longer underload.
Additional problems can arise if the lifting chain has too much or too little rotational freedom relative to the hook. If the hook is configured with a pneumatic line or other sources of power for the lock mechanism, care must be taken to protect the connections and ensure that the line is not entangled with the chain during operation. Also, hooks must be durable to withstand the rigors of the harsh handling environment, yet easy to service as necessary to avoid extensive downtime, e.g., during expensive procedures, such as a critical foundry operation or during unloading at a busy dock.
To address these and other problems in conventional hooks, some embodiments of the new lifting hook design allow the degree to which the hook may rotate relative to the chain to be selected as desired. The hook may be configured to provide for free rotation of the hook relative to the chain, e.g., as provided by a swiveling section of the hook assembly, or the relative rotation may be confined to a predetermined range, e.g., up to 180 degrees as one example. As another alternative, the hook may be rotationally fixed relative to the chain as desired, e.g., by securing the swiveling section relative to the hook.
Embodiments of the new lifting hook design can include a locking mechanism that operates along an axis distinct from a main or lifting axis of the assembly. By disassociating the locking axis from the main axis (usually the axis of the body of the lifting hook), the locking components may be accessed more readily. In some conventional hooks, the locking axis is usually coaxial with the body axis, but this design can complicate disassembly of the device and lengthen the time required for service. In embodiments of the new lifting hook, the distinct locking axis may be parallel to but offset from the body axis (i.e., to the right, left, front or rear), or the distinct locking axis can be angled relative to the body axis. In specific implementations, the locking device may be angled at about 45 or about 90 degrees relative to the body axis, although any other angle that sufficiently spaces the locking components from the body axis can be used, including an angle from about 15 degrees to about 90 degrees.
Embodiments of the new lifting hook design can include a hook clearing member that functions to push off the sling or other object within the hook as the hook is pivoted to an open position, thus assisting in ensuring that the hooks do not remain connected to slings unintentionally while the hooks are subject to being relocked.
Embodiments of the new lifting hook design can include a deliberate locking feature requiring a positive manual effort, e.g., against a predetermined resistance, to close the hook before it can be relocked in an effort to reduce instances of unintentional relocking.
Embodiments of the new lifting hook design can include a retractor that functions to urge the hook toward an open position when the hook is free to pivot.
The disclosed apparatus and methods should not be construed as limiting in any way. Instead, the present disclosure is directed toward novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and subcombinations with one another. The methods and apparatus are not limited to any specific aspect or feature or combinations thereof, nor do the disclosed methods and apparatus require that any one or more specific advantages be present or problems be solved.
Referring to
The swivel cap 14 is coupled to the body 12 by an attachment member 22 extending upwardly through the body 12 and into the swivel cap 14. The attachment member 22 may form a threaded connection or another type of connection. In the illustrated embodiment, the attachment member 22 is a socket head cap screw that also has a groove for receiving a transverse retaining pin 24 extending through the swivel cap 14.
A hook 30 is pivotably coupled to the body 12 by a pivot pin 28. The pivot pin 28 may be secured in position by a retaining pin 33 that engages a groove 35 on the pivot pin 28.
In
The hook 30 can be selectively secured or locked in the closed position with a lock mechanism. In the illustrated embodiments, a lock member, such as a lock pin 34, is selectively controlled to extend and engage a recess 36 formed in the hook 30, thereby preventing the hook from pivoting about the pivot pin 28. In the embodiment of
The lock pin 34 may be a rod of a piston (as shown in the illustrated embodiments), the plunger of a solenoid, or other type of controllably movable pawl or member. The lock pin 34 or locking member may be a single component that is directly coupled to the hook, or it may be a multiple component assembly in which the controllably movable member moves another member that contacts and secures the hook.
As shown in
The lock pin 34/piston 46 and spring 52 are secured in place by a cap 58 and a snap ring 60. The lock pin 34 and the piston 46 may be fitted with respective seals 54 and 56 as shown. The removable snap ring 60 and cap 58 allow easy access for servicing and/or changing the seals 54, 56 and the lock pin 34. There may be inspection openings 88 formed in the hook 30 and the body 12, which, when aligned as shown, e.g., in
A latch 40 for the hook 30 is coupled to the body 12. In the illustrated embodiments, the latch 40 is pivotably coupled to the body 12 by a pivot pin 41 and is biased to the closed position as shown in
As described, the hook 30 can be remotely controlled. For example, the hook 30 may be selectively controlled to withdraw the lock pin 34 from the recess 36, thereby allowing the hook 30 to pivot from the lock position to the pivoted position, e.g., to release the load. In the illustrated embodiments, the hook 30 is pneumatically controlled using compressed air or other compressed gas, such as nitrogen. In other implementations, a hydraulic system could be used. It would also be possible to use an electrically actuated solenoid, servo motor or other similar device.
In the embodiment shown in
The body 12 can be structured to provide protection for the fluid or power connection. For example, as shown in
In some embodiments, the lifting hook 10 may be fitted with a hook clearing member 84 that assists in ensuring that any sling within the hook is completely removed from the hook when the hook is pivoted from the lock position to the open position. In
Although shown as a separate piece in the illustrated embodiments, it would of course be possible for the hook clearing member 84 to be formed as one piece with the body. Alternatively, other hook clearing structures that incorporate a moving element to more positively assist in disengaging the sling from the hook could be used.
The hook clearing member 84 can also have a stop 85 positioned to contact the hook 30 and serve to prevent rotation of the hook beyond a predetermined “fully open” position. In
The hook may be fitted with a retracting member that urges the hook 30 toward the open position when the hook is free to pivot, e.g., when the lock pin 34 has been withdrawn. As best shown in
The lifting hook may have a deliberate engagement feature to prevent inadvertent locking of the hook 30 by the lock pin 34. Depending upon the position of the lifting hook at rest, e.g., if it was lying with its rear surface in contact with the floor or the top surface of the cargo, the hook 30 could be in a closed position and subject to being unintentionally relocked. Unintentional relocking could occur if the controlled unlock time for the lock pin expires, i.e., the piston 46 is allowed to close, while the hook is in the closed position. Unintentional relocking may be undesirable if there are still slings within the hook 30. A deliberate engagement feature such as a spring 72 can be positioned on the body 12 to bias the hook 30 slightly away from the closed position. Thus, the spring 72 requires the operator to manually apply a predetermined positive force to pivot the hook 30 to the fully closed position, and thus helps to ensure that the hook 30 is only fully closed when it is intended to be relocked.
The spring 72 may be a flat leaf spring held in place on the body 12 with a set screw as shown in
With the spring 72 or 72′, an attempt to relock the hook 30 will not be successful unless the biasing force of the spring is overcome, which would ordinarily require an operator's manual manipulation of the hook 30.
As indicated, the swivel cap 14 can be configured (1) to rotate freely, i.e., over at least 360 degrees relative to the body 12, (2) to rotate over a desired angular range (e.g., over about 180 degrees) relative to the body 12, or (3) to be fixed and not rotate relative to the body 12. If free rotation is desired, the body 12 and the swivel cap 14 are assembled together without the pin 76. If rotation over an angular range is desired, the pin 76 is inserted into the body pin aperture 80, and the swivel cap 14 is assembled together with the body 12 such that the pin 76 is in a slot 78 of the desired angular range.
The selective rotation functionality can be made available for use while the lifting hook is assembled. For example, a longer pin 76 can be used in conjunction with a cap pin aperture 80 that extends through the swivel cap 14 cap to provide the user with the ability to select the desired relative rotation. If limited rotation is desired, the protruding pin is depressed to engage the body pin aperture 82 (no rotation) or the slot 78 (rotation only a limited angular range) in the body 12. The pin can be secured against unintentional movement, e.g., by use of a detent or similar retainer.
As indicated above, the lifting hook can be configured such that the locking axis is not coaxial with the axis of the body. In some embodiments, the locking axis and the axis of the body intersect to form an acute angle. In still other embodiments, as in the embodiment of
For other implementations, such as is shown in the embodiment of
As best shown in
In general, it is desirable to construct the lifting hook such that the outermost surfaces tend to slide away from objects with which they make inadvertent contact during use, instead of catching on or snagging such objects. In use, the lifting hooks are generally suspended in a generally upright position, i.e., with the body axis B generally vertical. Therefore, viewing the lifting hook in elevation, the outermost surfaces that might come into inadvertent contact with, e.g., the side of a cargo ship, are generally gently sloping or curved, and the use of planar surfaces or projections (e.g., the heads of fasteners), which might be prone to interfere with and “grab” objects, is minimized. Thus, the overall construction of the lifting hooks in the described embodiments is referred to as “non-snagging.”
The various components of the lifting hook 10 may be made of any suitable material. In most implementations, the major components are made of a steel. Other materials, such as fiberglass, plastics, composites, ceramics, etc., are also suitable, depending upon the particular environmental conditions and operating requirements. In some implementations, certain components are made of a material resistant to environmental effects, e.g., stainless steel or variations of bronze may be used for one or more components where corrosion is a concern.
Although the invention has been disclosed in this patent application by reference to the details of some preferred embodiments, it is to be understood that this disclosure is intended in an illustrative rather than in a limiting sense, as it is contemplated that modifications will readily occur to those skilled in the art within the spirit of the invention.
The present application claims the benefit of U.S. Provisional Application No. 60/528,759, filed on Dec. 10, 2003. The prior application is incorporated herein by this reference.
Number | Date | Country | |
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60528759 | Dec 2003 | US |