Patent Application
20240400355
The invention relates a pulley block that is modular having a load plate that enables interchanging of the side plates, bushings and wheels without changing the load carrying capacity, which enables spark prevention and the use of corrosion resistant materials for the side plates and other components that may otherwise require metal parts.
Pulley blocks are used in various industrial applications such as marine rigging, construction equipment, and logging to give direction to the rope while loaded and increase the line pull or lifting capacity of a hoist or winch. Pulley blocks are routinely used for lifting or moving heavy objects. The blocks have a sheave with a cable guide for retaining the cable as it spin around the sheave. In some applications it is important to prevent sparking due to a metallic cable moving through a block and sparking due to contact with metallic parts of the block. In these situations, the contact parts may be made of a non-sparking material such as a polymer, or composites, such as carbon fiber.
In some situations, synthetic or polymeric cables are used and the contacts within the block can be rough due to corrosion and this can produce wear on the synthetic cables. Metallic components can rust and corrode in the elements producing rough surfaces that are not well suited for synthetic cable use.
The invention is directed to a modular block that may be used as a pulley block, pulley sheave, cable block, cable sheave, or variations thereof. For the purposes of this description, these terms may be used interchangeably to describe a structure in which a wheel is mounted wherein a cable or cable-like member (such as but not limited to a cable, rope, string, cord, etc.) is configured to translate along the wheel. The modular block of has load wye plates on opposing sides of the block that carry the load from the load fasteners, coupled to a split load block, to the axle fastener, extending through the sheave wheel and wheel aperture of the sheave. This load transfer arrangement enables other components of the block to be made of lower weight non-metallic materials, such as polymers or carbon fiber composites. In addition, this load transfer arrangement with the load wye plates enables contact components, components that may contact the cable to be non-metallic or non-sparking, such as polymers or carbon fiber composites. The use of non-metallic components may significantly reduce the weight of the block making it easier to manipulate and transport. Also, the modular block is modular, allowing for components to be interchanged for a given application, wherein the material types of the components may be changed, or the size or geometry of the components may be changed.
An exemplary modular block has a pair of load fasteners that retain an eye having a mount aperture for securing the modular block to a support. The eye may be a fixed eye or may be configured to swivel, thereby allowing the modular block to swivel with respect to a support it is affixed to. A fixed eye may be attached to a load block and the load fasteners may extend through apertures in the load block to secure the fixed eye to the modular block. A swivel eye may be preferred in many applications as it may aid in reducing wear on the sheave due to the cable being pulled at an offset angle. A swivel eye will enable the modular block and sheave to swivel into alignment with the cable extending around the sheave. In the case of a swivel eye, a pair of load fasteners extend through a pair of split load blocks that extend around a retainer shank of the swivel eye to enable the swivel eye to rotate. A base flange of the swivel eye secures the swivel eye between the split load blocks.
An eye, fixed eye or swivel eye, may be made be made of a material or coated with a material to prevent corrosion and/or sparking from contact with the cable. The eye is a load carrying member and therefore may preferably be made of metal, such as steel or tempered steel for strength, for example. The eye may have corrosive resistant coating and/or a spark resistant coating which may include a paint, polymer or anodized coating which may be a different metal than the metal the eye is made of.
The load fasteners extend through load wye plates configured on either side of the modular block. The load wye plates extend from the load fastener apertures to the rotational axis of the sheave and has an axle fastener aperture. The load on the modular block is therefore carried by the axle fastener extending through the sheave wheel aperture and through the axle fastener apertures in the load wye plates, by the load wye plates, and then by the load fasteners extending through the load fastener apertures in the load wye plate, and finally by the eye or swivel eye. The load wye plates each have three apertures for supporting fasteners that carry the load. This configuration enables the other components of the modular block to have lower weight carrying capacity and therefore can be made of non-metallic parts, such as polymers. For example, the side plates, as well as the sheave or sheave wheel may be made of polymeric or composite materials that prevent sparking when a metallic cable is used. The primary contact surface with the cable are the side plates and the sheave. The base flange of the eye may also be a contact surface for the cable and therefore may be made of a non-sparking material or coated with a non-sparking material, such as a polymeric material.
The configuration of the fasteners through the load wye plates and the load wye plates carrying the load enables the other components of the modular block to be interchanged as required for the application. The size or geometry of the other components may be quick interchanged as requirements for the modular block change. Also, as described herein, lower weight components may be used and the load to weight ratio greatly increased for the modular block. In addition, the contact surfaces of the block, such as the side plates and the sheave may be changed out more regularly due to wear from contact with the cable.
The side plates may be very thin as they carry no load from the cable and therefore may be no more than about 8 mm, no more than about 5 mm, no more than about 4 mm, no more than about 2 mm and any range between and including the thickness values provided. A thin side plate reduces the mass of the block.
The load wye plate has load extension arms that extend from the wheel portion at an offset angle. The angle may be within a certain range to enable high load carrying capacity at a reduced weight of the load wye plate. A very large offset angle, such as more than 90 degrees may put more bending force on the extension arms at the connection with the wheel portion which may lead to failure at very high loads. The angle must be large enough to position the load fastener apertures to fit through the split load block. Therefore, an offset angle of about 25 degrees or more, about 30 degrees or more, about 45 degrees or less, about 60 degrees or less, about 75 degrees or less, and less than 90 may be effective offset angles. An offset angle in the range from about 25 degrees to about 50 degrees may be a preferred for weight and load carrying capacity considerations.
An exemplary modular block may be sized for a given application and may have a sheave with a diameter of about 10 cm or more, about 15 cm or more, about 20 cm or more, about 25 cm or more, about 40 cm or more, and any range between and including the diameters provided.
A modular block may be required to carry a high load induce by the tension on the cable extending around the sheave, such as about 1,814 kb (4,000 lb) or more, about 2,721 kg (6,000 lbs) or more, about 4,536 kg (10,000 lbs) or more, about 7,257 kg (16,000 lbs) or more about 9,072 (20,000 lbs) or more and any range between and including the loads values provided. A block may be tested by the application of a load, wherein the block cannot deform under a load or break or otherwise fail under a load, such as described in ASTM-E4.
A polymer, as used herein, may be a thermoplastic polymer, such as polyethylene, or a thermoset polymer that is cross-linked. A polymer may be an ultrahigh molecular weight polymer having a molecular mass of about 3.5 million atomic mass units (amu) or more, about 5.0 million amu or more about 7.0 million amu or more and any range between and including the values provided. An exemplary polymer for use as the side plate or sheave may be an ultrahigh molecular weight polyethylene UHMWPE that has a molecular weight of about 1million g/mole or more, about 2 million g/mole or more, about 3 million g/mole or more and any range between and including the values provided.
Non-metallic, as used herein, is a material that is made of materials such as polymer or plastic that does not include a metal. As described herein, components of the modular block may be made of non-metallic materials to prevent sparking with contact with the cable which may be metal. A component of the modular pulley block may consists of, or consists essentially of non-metallic material, wherein no more than 5% of the weight is metallic. A component consisting of non-metallic material has no metallic material.
A modular pulley block is referred to as a modular block or simply a block herein.
The summary of the invention is provided as a general introduction to some of the embodiments of the invention, and is not intended to be limiting. Additional example embodiments including variations and alternative configurations of the invention are provided herein.
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.
Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, use of “a” or “an” are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.
Certain exemplary embodiments of the present invention are described herein and are illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention. Other embodiments of the invention, and certain modifications, combinations and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, combinations, modifications, improvements are within the scope of the present invention.
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A sheave wheel 80 is configured within the sheave 110 and a bushing 90 is configured within the sheave wheel 80 to enable rotation of the sheave wheel and the sheave 110. A sheave spacer 30 is configured within the bushing 90 whereby the sheave 110, sheave wheel 80, bushing 90, and sheave spacer 30 are concentric. The sheave 110 has a rotational axis 115 about which the sheave rotates and along with the axle fastener 48 extends from a first side 7 to a second side 9 of the modular block 5.
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Two load extension arms 22, 24 extend from the wheel portion 26 at an offset angle 21 to each other. A load fastener aperture 23, 25 is configured at the end of each load extension arm 22, 24. A load fastener (not shown in
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It will be apparent to those skilled in the art that various modifications, combinations and variations can be made in the present invention without departing from the scope of the invention. Specific embodiments, features and elements described herein may be modified, and/or combined in any suitable manner. Thus, it is intended that the present invention cover the modifications, combinations and variations of this invention provided they come within the scope of the appended claims and their equivalents.
