Patent Application
20150292180
The present invention relates to pins used in rigging for excavating equipment to join components that rotate about the pin axis relative to each other.
Mechanical pins are commonly used to join components that rotate in relation to each other. A pin passes through an opening of each of the components and is retained by, for example, a retainer on the pin or in the opening. The openings and the pin surface form bearing surfaces as the components pivot. The relative movement of the joined components wears on the pin and erodes the surface. After a certain amount of wear, the pin and/or the components have to be replaced. In aggressive environments, the pins and the components wear quickly and require frequent replacement.
Mining equipment uses pins extensively to join very large components used in highly abrasive environments. As one example, such pins are commonly used in rigging for dragline operations. The rigging handles extreme loads in pulling the bucket to collect blasted earthen material and then lifting the filled bucket. Moreover, particulates from rock and ore (termed fines) infiltrate any available gap and act as abrasives that erode bearing surfaces and exposed surfaces until the components are unserviceable. The service life for some ground engaging tools can be as short as 36 hours. Replacing these components can be time consuming and generally takes the equipment out of service for the duration of the refurbishment.
Handling these heavy components requires hoists, cranes and lifts and the procedures can be hazardous to the operators. To install a pin to the components, the component openings are first aligned by lifting, positioning and holding the components in the correct position. Force is then applied to the pin and the components to more precisely align the openings while simultaneously urging the pin into the openings. The end of the pin is generally blunt and of the same diameter as the openings making alignment and insertion difficult. The pin is pushed into the opening while the components are manually aligned to allow the pin to pass through. Generally an operator using a sledge hammer makes the final alignment of the large components. Extensive positioning and alignment of the heavy components puts the operators at risk of injury and generally requires a great deal of downtime for the equipment.
Removing the pin again requires supporting each of the attached components separately to remove the load from the pin so that it does not bind in the opening and pounding on the end of the pin to dislodge and extract the pin from the component openings. Mining operations often run 24 hours a day and downtime required for this kind of maintenance can have a significant effect on profitability.
Mining equipment operates in high load and extremely abrasive environments with dust and debris that penetrate every crevice. Even components that are not intended to contact the earthen materials are affected by the sand and dust generated during processing. As a result, the components are heavy, cumbersome and high abrasion resistant.
The pin assembly of the present invention reduces the handling of the components, the time required for installing and removing pins from equipment, and the downtime required for maintenance. The pin assembly can thus provide greater productivity for mining or other related operations. The pin assembly also improves safety by reducing hazards to the operator(s) installing the pin in the components. The pin assembly provides for reduced wear of the components during operation. The pin assembly protects the end of the pin from wear and limits the risk of cables passing over the assembly from catching. Although discussed in terms of mining equipment for the purpose of illustration, this assembly can be used in other heavy duty equipment where pins are installed in openings of components.
An inventive concept of the present invention pertains to a method for pivotally joining first and second components each having an aperture for use in excavating equipment. The method comprises the steps of securing a tapered lead having a wide end and a narrow end to an end of a pin with the wide end proximate the pin. The narrow end of the lead is inserted into one of the apertures and the lead and the pin behind the lead are advanced into and through the apertures so the pin is in an installed position in each of the apertures.
Another inventive concept of the invention is a rigging pin assembly for securing components for excavating equipment or digging machines together for pivotal movement. The pin assembly comprises a pin with a central portion including a cylindrical exterior having a first thickness defined as the diameter of the cylindrical exterior and an end portion. The end portion includes a connecting portion and a flange coupled together extending outward from the main portion and has a second thickness that is less than the first thickness. The flange is spaced outward of the central portion and has a third thickness that is less than the first thickness and greater than the second thickness. The flange and the central portion define a groove about the connecting portion. The pin assembly also includes a retainer to secure the pin within aligned apertures of the components. The retainer includes first and second members and at least one fastener to join the first and second members in the form of a ring. The first and second members include an inner portion to seat in the groove and an outer portion defining a recess radially outward of the inner portion to receive and hold the flange
Another inventive concept of the invention is a pin assembly for pivotally connecting components together for excavating equipment where each of the components include an aperture. The pin assembly comprises a pin including a central portion to be received into the apertures and a pair of opposite ends, and a lead including a proximal end secured to one of the ends of the pin and a distal end projecting axially outward of the pin. The distal end is narrower than the proximal end to ease installation of the pin into the apertures.
In one other inventive concept of the present invention, a ferrule for mounting to a pin for joining components together for excavating equipment. The ferrule comprises first and second separable sections that together define a ferrule body with a cavity that receives and retains a flange on the end of the pin, a tapered sleeve that receives a tapered surface of the ferrule body and limits separation of the ferrule sections and a retainer to limit separation of the sleeve and the body.
In another concept of the present invention, a collar for limiting axial movement of a pin installed in a component comprises a first collar portion with mating surfaces and a second collar portion with mating surfaces. The first portion assembles to the second portion at the mating surfaces to define a stepped opening with a first inside diameter corresponding to a recess of the pin and an adjacent larger diameter corresponding to a flange of the pin.
Another inventive concept of the present invention pertains to a rigging assembly comprising a plurality of components for excavating equipment where each of the components includes apertures. The rigging assembly includes a pin with a central portion to be received into the apertures and a pair of opposite ends and a lead including a proximal end secured to one of the ends of the pin and a distal end projecting axially outward of the pin. The distal end of the lead is narrower than the proximal end to ease installation of the pin into the apertures.
Another inventive concept of the present invention pertains to a lead for installing a pin in an opening of a component. The lead includes an elongate body that converges extending from a rearward end to a forward end with a rearward opening cavity. The cavity includes a circumferential ridge with a first diameter and a cavity portion forward of the ridge with a diameter greater than the ridge diameter to receive a flange of a pin.
Another inventive concept of the present invention pertains to a coupling pin where at least one end includes a groove and flange. This pin construction can facilitate easier and quicker assembly with and disassembly from the components, and/or improved retention of the pin in the assembly.
In an embodiment of the present invention that achieves each of the desired benefits, a flange of reduced size than the component supporting portion of the pin is formed at one end of the pin, though other constructions are possible. With this construction, the pin can be guided and pulled through the components to be connected for an easy and quick assembly process with less risk to the operator. This construction also facilitates the use of an improved, easy-to-use and quick to release or engage retainers to secure the pin in the assembly.
Another inventive concept of the present invention pertains to an assembly and/or process where the pin is pulled through the various holes in the components to be connected together, and/or pulled through the various holes to remove the pin from the components. The ability to pull the pin through the components can ease and speed the process, reduce handling of components, and eliminate (or at least reduce) the need for a hammer. As a result, a process can be achieved that takes less time and exposes the operator to fewer hazards during assembly.
In an embodiment of the present invention that achieves each of the desired benefits, a guide is secured to one end of the pin that provides a tapered leading profile to facilitate easier insertion into the holes, and component alignment as the pin passes into the holes of the components. Although other arrangements are possible, one preferred means is to secure the guide to a flange and groove construction on the end of the pin.
Another innovation of the present invention pertains to an improved retainer for retaining the pin in the assembly that is easy and quick to secure and release for easier inspection and removal of the pins in an assembly, and/or reduce the risk of cables catching on the assemblies.
In an embodiment that achieves each of the desired benefits, the retainer is formed by a pair of complementary cap members that couple to the ends of the pin to prevent axial movement of the pin, are secured together and/or to the pin by fastener(s) that are easily accessed and operated, and form a smooth exterior surface that lessens the risk of catching passing cables. Though other constructions are possible, one preferred arrangement includes a pair of identical generally U-shaped cap members secured together about a flange and groove construction at the end of the pin. The exteriors of the cap members is smooth and rounded to avoid catching passing cables.
The different inventive concepts can be used independently without the other inventive concepts in a pin assembly to achieve one or more of the various benefits of the present invention. This application primarily discloses one preferred embodiment to achieve all the desired benefits. For example, in one preferred embodiment, a pin assembly includes a pin with a center portion, a groove portion extending from each end of the center portion and a flange extending from the groove portion. The pin assembly in an installation configuration further includes a ferrule assembly with a ferrule body that engages the flange at a proximal end. The ferrule assembly converges extending away from the pin along a longitudinal axis of the pin to a distal end. The pin portions and the ferrule assembly extend along the longitudinal axis. The pin assembly with the ferrule and pin are pulled through openings of components to be joined.
In some embodiments the elongate ferrule body comprises two portions that on assembly define a cavity to receive and engage the flange. The assembled ferrule then receives a tapered sleeve that conforms to the tapered surface of the ferrule body and limits transverse movement of the ferrule portions. When axial movement of the sleeve is limited by a retainer through the narrow end of the ferrule, the ferrule is secured to the end of the pin by the flange engaged in the cavity of the ferrule assembly. Other configurations of the ferrule are possible that secure the tapered ferrule to the pin and the flange.
The pin assembly in an operational configuration can also include one or more collars that engage the flange and groove to limit axial movement of the pin during equipment operations. The collars are received in the groove of the pin and contact the outer circumferential face of the flange.
In another aspect of the invention a method for installing a pin assembly in an opening of a component comprises providing a pin with a center portion, a groove portion extending from the center portion and a flange extending from the groove portion along the longitudinal axis. A tapered ferrule is then attached to the flange of the pin. The ferrule is a smaller diameter than the pin and converges extending axially from the pin. The ferrule includes a cavity that receives the flange. The cavity also includes a rail that is received in the groove of the pin. Pulling on the ferrule and/or pushing on the trailing end urges the pin into the component opening. The increasing diameter of the ferrule aligns the component openings as the pin is installed.
In another aspect of the invention a collar for retaining a pin in the opening of a component comprises a first collar portion with an inside bearing face, an arcuate outer face and two mating surfaces and a second collar portion with an inside bearing face, an arcuate outer face and two mating surfaces. The first portion assembled to the second portion are joined at the mating surfaces to define a stepped opening with a first inside diameter corresponding to a recess of the pin and a second larger diameter adjacent to and outside the first diameter corresponding to a flange of the pin. The collar can include a pair of holes that each pass through both portions of the split body and through the mating faces. Each hole receives a retainer that secures the portions of the split collar together. The mating faces of the collar portions include corresponding recesses and protrusions. When assembled together the protrusions received in the recesses limit sliding of the mating faces in relation to each other.
In another aspect of the invention a pin includes a center portion with a major diameter, a groove portion with a minor diameter extending from each end of the center portion and a flange with a median diameter extending from the groove portion. The pin can be installed to components by engaging and applying tension at the flange to pull the pin into an opening of the component.
In another aspect of the invention an adapter for installing a pin in an opening of a component comprises an elongate body generally round in cross section that converges extending from a proximal end to a distal end. A cavity that opens at the proximal end of the body includes a circumferential ridge with a first diameter and a cavity portion forward of the ridge with a diameter greater than the ridge diameter. The adapter is assembled to a flange of a pin. Pulling the adapter and pin into the opening of the components urges the components into alignment as the progressively larger diameter of the tapered body passes into the openings of the components.
Mining operations employ heavy equipment, some of which include coupling pins. As one example, dragline operations require large and heavy rigging to move and hoist drag buckets used in open pit mines. The rigging uses pins extensively to hold many of the components together. In operation, these pins are exposed to abrasive particles that infiltrate any gap in the assemblies. These particles combined with the extreme loads seen by the pins limit the service life of the components by eroding exposed and mating surfaces until the components are not serviceable. Refurbishing the rigging requires handling parts weighing tons and aligning combinations of parts to accommodate the assembly and disassembly of the pins from the components. Handling these large parts can be dangerous for the operators and can take the equipment out of service for long periods. Although dragline operations are disclosed herein as an example for the present invention, the invention can be used to pivotally secure components for other excavating machines such as cable shovels. In all such uses, the components will be herein considered to be rigging or rigging pin assemblies regardless of the excavating machine in which they are used.
Once filled, the bucket is lifted by cables through upper hoist rigging assembly 20 connected to the bucket by upper hoist chains 22 and lower hoist chains 24 to trunnions 26 of the bucket. Once lifted off the ground the bucket can be repositioned to a dump site for spoiling material. When tension is released on the drag link, the dump cable 28 passing through the dump block 30 releases allowing the bucket to rotate about the trunnion point well back of the center of gravity and tip forward so that the earthen materials are dumped from the bucket. The connections between the cables, chains and the bucket include one or several pins to secure the components to adjacent components.
A pin assembly that provides more efficient installation and extraction of the pin is generally shown in
In the preferred embodiment, the pin is elongate with a longitudinal axis L, a center portion 52A with a major diameter and a major length and a circumferential groove portion 52B with a minor diameter smaller than the major diameter. Outboard of the groove is a flange 52C with a median diameter at a circumferential surface larger than the groove portion and smaller than the center portion. The flange is preferably larger than the groove and smaller than the component-supporting portion of the pin but need not be circular. The flange could also have the same size as the component-supporting portion of the pin and provide other means or clearances for connecting the guide and/or retention collar. In such cases, the groove could be replaced with other cavity arrangements to effect attachment of a lead and retainer.
Retention collar 54 is preferably two portions 54A and 54B with stepped openings 54C and 54D that correspond to the circumferences of the groove 52B and the flange 52C of the pin, but other arrangements are possible. The inner step opening 54C is received in the groove of the pin. The outer step 54D of the opening contacts the outer circumference of the flange. An outer facing surface 54I of the collar can be arcuate extending away from the flange to allow any cables that slide along the surface to pass over the collar without catching as could happen with a protruding square edge. An inner bearing surface 54J of the collar faces the component. The collar limits axial movement of the pin in the opening of the component receiving the pin.
Mating surfaces 54K and 54L of the collar portions include corresponding protrusions 54G and recesses 54H. The collar portions assemble with protrusions 54G in recesses 54H to form the collar as a ring and defining the stepped opening. Recessed bores or holes 54E extend through the body of the collar and through the mating surfaces. The bores accept retainers 54F which hold the two portions together. The recesses and protrusions when mated limit shear movement between the faces and resist shearing forces applied to the assembled collar. This allows a smaller retainer to be used to hold the collar portions together. Smooth mating surfaces would subject the retainer to all of the shear movement at the mating surfaces and would require a larger retainer than would be required with the mating protrusions and recesses. This could be done as an alternative.
When assembled to pin 52, the surface defining opening 54C of the collar is received in groove 52B and the surface defining outer opening 54D contacts the circumferential surface of the flange. The collar is preferably sized to cover a large portion or the entire outer circumference of the flange but other arrangements are possible. The collar in the preferred embodiment protects and limits erosion of the flange during operation.
To install or remove the pin from the component, the lead 56 is attached to one end of the pin 52. In a preferred embodiment, the lead is a ferrule assembly that includes two portions 56A and 56B that assemble to define a ferrule body 56E. The ferrule portions joined together further define a cavity 56C at a proximal end of the ferrule that engages flange 52C of the pin with a protruding rail 56D in the wall of the cavity which is received by groove 52B. The cavity has a reduced diameter at the rail 56D. Forward of the rail the cavity has a larger diameter corresponding to the flange of the pin. The balance of the cavity generally extends forward for compatibility with the casting process, but the cavity in some cases may not extend forward beyond the flange area. While the ferrule assembly is preferably composed of cast components, the parts could be fabricated in other ways. The ferrule exterior surface converges extending away from the pin to a distal end.
The assembled ferrule body receives a sleeve 57 with an inside channel that converges extending from a proximal opening to a distal opening. The channel generally conforms to the tapered exterior surface of the assembled ferrule. The sleeve assembled to the ferrule body limits transverse displacement of the ferrule portions to secure them together. The distal end of the ferrule can extend beyond the sleeve 57.
The ferrule distal end includes an engagement feature 62. The engagement feature at the distal end provides an attachment point for supporting and drawing on the pin. The engagement feature can include an opening 58 passing transversely through the ferrule portions. A component such as a shackle 60 can be installed through the opening. The shackle when installed to the engagement point can be larger than the diameter of the distal opening of the sleeve to limit axial movement of the sleeve and to simultaneously provide an attachment point. The shackle limits movement of the sleeve and provides an engagement point for a cable or sling.
Other attachment point arrangements can be used that perform a similar function. The sleeve retainer and engagement feature can be separate components and the ferrule distal end can have multiple openings. Alternatively, a sleeve retainer 57′ as shown in
The guide or ferrule 56 could also be secured to the pin without the provision of a groove and flange on the pin. As an example only, the guide could be secured in a threaded bore in the end of the pin. Guide 56 could also have numerous differences than the preferred embodiment disclosed above.
Previously when refurbishing rigging, to install a pin to join components, the component openings are first closely aligned by lifting and positioning the components with cranes and lifts to align the pins and the openings. Force is then applied to the components to more precisely align the openings while urging the pin forward into the openings from the back end. The forward end of the pin is the same diameter as the openings so there is no purchase for pulling on the pin.
In the preferred construction of the present invention, the flange of the pin is of a smaller diameter than the major diameter of the pin. When assembled to the pin with the flange retained in the cavity of the guide or ferrule, the diameter of the ferrule assembly is less than the major diameter of the pin. To assemble the pin with the ferrule assembly to the components, the first component 64 and the second component 62 to be joined by the pin are positioned to align the openings 62A and 64A of both components. The narrow distal end of the guide or ferrule assembly is positioned in the opening of the first component.
A cable or other line or implement can be connected to the engagement point of the guide. Tension applied to the cable draws the pin into the aligned openings as shown in
Alternatively, a sleeve retainer 57′ can be installed to the distal end of the guide without a shackle providing a smooth surface for entry to the openings. The pin is installed to the opening of the component primarily by pushing the back end of the pin. The tapered adapter again acts to align the components as it passes into the openings.
With the pin fully installed in the opening defined by aligned openings or component surfaces 62A and 64A, the guide 56 can be replaced by a collar 54 assembled to the pin. In a preferred embodiment the component 64 generally includes an outward facing surface 64B proximate the end of the installed pin. The outward facing surface can include a recessed portion 64D proximate to the opening with a bearing surface 64C for receiving the collar. When installed, the groove 52B of the pin can be proximate the bearing surface and entirely outside of the opening on both sides of the component. The bearing surface 64C defining the recess 64D of the component 64 is substantially perpendicular to the longitudinal axis of the opening and is sized to allow the two portions of the collar to be positioned against the bearing surface and to move transversely into the groove without rotation of the collar portion that could wedge the collar portion in the groove on installation. The bearing surface 54J of the installed collar faces the bearing surface 64C of the component. Alternatively, the outside surface of the component can be generally smooth without recesses.
The outer surface of the component together with a curved′outer face 54I of the collar in the recess provides an outer surface of the assembly with smooth continuous contours that allow a cable to slide over the surface without catching. The smooth surface also limits erosion of the surface that occurs with exposed sharp or blunt surfaces.
The area of the flange can be less than 80% of the center portion of the pin and the area of pin at the groove can be less than 70% of the center portion. In a preferred embodiment the cross sectional area of the flange transverse to the longitudinal axis can is between 80% and 60% of the area of the center portion of the pin and the area of pin at the groove can be between 70% and 50% of the area of the center portion. Other ranges of relative dimensions are possible. The pin is preferably symmetrical from end to end, but the pin can have different configurations on each end.
In a preferred embodiment the width of the flange is one inch (2.54 cm) and the width of the groove is two inches (5.08 cm), but the groove and/or the flange can have larger or smaller widths. The length of the pin center portion is generally defined by the length of the openings of the component assembly the pin is to be installed in. The grooves preferably are just outside of the component openings but they could be located fully or partially within the openings if desired. If the grooves are spaced too far from the openings, the pin risks having too much play moving longitudinally in the openings during certain operations and the flange and the collars may then extend farther from the components than necessary. If the grooves are not spaced from the opening adequately, it may be more difficult to install the collars into the grooves in certain arrangements. Nevertheless, the invention is not limited to the position of the grooves relative to the openings or components, or to even having grooves in the pin. The above discussion is intended to describe the preferred construction of the pin.
The guide can have other configurations that perform a similar function and still fall within the scope of this disclosure. In an alternative embodiment ferrule assembly 100 includes ferrule body portions that are not symmetrical. First ferrule portion 100A is much larger than second ferrule portion 100E as shown in
In another alternative embodiment, ferrule assembly 110 includes a ferrule portion 110A with a rearward opening cavity 110B to receive the pin flange and an adapter. Two portions of an adapter 110C and 110D similar to collar 54 are assembled around the pin flange. The inside surface of the adapter includes a rail 110E received by the groove of the pin adjacent the flange as shown in
Another alternative configuration of the pin assembly is shown in
The pin assembly in the installation configuration can include a collar installed on the trailing end of the pin as the pin is installed into the component openings. Alternatively the pin can be installed with only the ferrule assembly and without any collar assembled to the pin. Once the pin is installed with the ferrule in the openings, one or both collars are attached to the pin to limit axial movement of the pin during operation.
The pin assemblies in the operational configuration with collars on each end of the pin as shown to this point are free to rotate within the component openings. In some applications it is preferred that the pin be fixed to rotate with one of the joined components while the second component rotates freely about the pin. A fixed pin assembly 160 is shown in
Alternatively, the flange can be of similar diameter to the body of the pin. The ferrule can engage only the flats 168 of the flange and the groove 152B to extend from the end of the pin with a diameter less than the body of the pin. The pin assembly can then be installed to a component as previously described by pulling on the flange to advance it into the opening while the ferrule engages the pin flange at the flats.
Collar 154 comprises two halves 154A and 154B with an outside surface that includes opposing flat ends 172 on each half. Joined together the collar halves define a stepped opening. The stepped opening includes a round portion 154C with a diameter corresponding to groove 152B and a second stepped opening 154D coaxial with the first opening that corresponds to the flange 152C. Opening 154D includes a round portion and a flat portion 170 that correspond to flats 168 of the flange 152C. The collar can incorporate features similar to
Fixed pin assembly 160 is installed to join a component 164 to component 162. Component 164 includes bearing surfaces defining opening 164A and a longitudinal axis 164L. Outer surface 164B includes a recess 164D with a bearing surface 164C. The recess includes flat walls 174 that correspond to the flats 172 of the collar.
The pin is assembled to the component assembly in a similar manner as previously described. With the pin in an installed position in the openings of the components, the grooves are proximate the recess of the outward surfaces on opposite sides of the component. Collar 154 is assembled to the pin by positioning the first collar portion in the recess with the flats 172 adjacent the flat walls 174 of the recess. The collar portion translates or slides so the opening portion 154C sits in groove 152B of the pin and the flats 170 of the second collar opening are adjacent the flats 168 of the pin flange. The second collar portion is similarly installed to the groove and flange.
Retainers 154F in holes 154E secure the portions together. Rotation of the collar in the recess and in relation to the component 164 is limited by the corresponding flats of the recess bearing on the corresponding flats of the collar. Rotation of the pin in relation to the collar and to component 164 is limited by the flats of the pin flange bearing on the flats of the collar opening. Component 162 is free to rotate about the pin 152.
Again, the pin assembly in the operational configuration is typically symmetrical on each end of the pin, but can include different collar configurations on each end. In an alternative example, one end of the pin and the component can include a collar similar to
This is one example of a fixed pin assembly and other configurations are possible. The flats of the collar outside surface and the flats in the collar opening are perpendicular in this example, but they could be parallel. There could be more or fewer corresponding orienting or coupling surfaces than the number of flats shown. The orienting surfaces could be a different shape than those shown. The ferrule and collar opening could be square in cross section or could be oblong. The flats of the pin could be in the recess rather than on the flange and a corresponding flat can be on the corresponding inner step of the opening of the collar. Any arrangement of disclosed features that performs a similar function as that shown will fall within the scope of this disclosure.
In an alternative embodiment, an integral collar can be included on one end of the pin.
The ferrule assembly is advantageous in that it allows the components to initially be only generally aligned. Passage of the ferrule assembly into the openings further aligns the openings. The ferrule assembly also provides for tension to be applied to the pin where, without the flange and/or the ferrule assembly, there is no effective way to engage the forward end of the pin and the pin has to be pushed into the opening. The pin system is also advantageous in that the collars can be stocked for standard pin diameters to be installed without welding. The pins are easily cut from standard bar stock and the groove and flange can be machined with standard equipment and skills. Orders for the pin assemblies can be filled close to the mining operation where they are required reducing time required for order fulfillment.
Previous rigging components sometimes used retainers such as collars that were inserted into cavities in the arm of the component to engage and retain the pin flush in the component rather than the retainer engaging the pin outside the component. This requires more complicated casting for the component to form cavities in the bodies and the cavities are subject to clogging with fines. The present invention does not require complex component castings and can be retrofit to almost any existing component configuration that includes a through aperture.
It is believed that the disclosure set forth herein encompasses multiple distinct inventions with independent utility. While a lead for a pin has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. While different configurations have been described to achieve a specific functionality combinations of these configurations may be used and still fall within the scope of this disclosure. Where the description recites “a” or “a first” element or the equivalent thereof, such description includes one or more such elements, neither requiring nor excluding two or more such elements. Further, ordinal indicators, such as first, second or third, for identified elements are used to distinguish between the elements, and do not indicate a required or limited number of such elements, and do not indicate a particular position or order of such elements unless otherwise specifically stated.
| Number | Date | Country | |
|---|---|---|---|
| 61977449 | Apr 2014 | US |
