1. Field
Embodiments of the invention relate to cranes. More specifically, embodiments of the invention relate to luffing jibs for cranes.
2. Related Art
Cranes, digger derricks, and other heavy equipment utilize a boom assembly, a load line, and a winch to lift heavy loads. The winch is typically disposed on a base, and the load line runs from the winch along the boom assembly to an implement at the distal end of the boom. The implement then routes the load line downward so as to allow a load to be attached thereto. The winch may then be operated to reduce the available length of the load line and therefore lift the load.
Luffing cranes allow the crane to lift the load over a high or large obstacle. The luffing crane enables an operator to move the load laterally along the ground while elevated off the ground. The luffing crane keeps the load at a substantially static height above the ground while moving the load toward or away from the boom. The luffing crane accomplishes this by adjusting an angle of the luffing jib relative to the boom assembly while adjusting the boom angle.
The luffing jib of a luffing crane is typically very large and heavy. As such, it must be transported to a worksite separately from the crane. They also require an additional crane to assist in installation of the luffing jib. Further, luffing jibs also require the operator to run additional hydraulic lines to provide hydraulic power to the luffing jib. This procedure is very time- and labor-intensive. For example, the luffing crane requires three vehicles to be present (i.e., the luffing crane, an assisting crane, and a transportation vehicle). Because of the difficulty and time required to set up, luffing cranes are only used sparingly, such as when a specific need is present at a worksite. What is lacking in the prior art is a luffing crane that is easy and convenient to use.
Embodiments of the invention solve the above-mentioned problems by providing a compact stowable luffing jib for use on a crane. The stowable luffing jib stows on a boom assembly of the crane when not in use. The stowable luffing jib is therefore always on the boom assembly such that no external transportation is necessary. The stowable luffing jib is configured to connect to a distal end of the boom assembly and swing out from a stowed position to a deployed position. This is accomplished manually by the operator and requires no assisting crane to install the luffing jib. Further, no additional hydraulic lines are needed to perform the luffing functions. The installation and use of the stowable luffing jib is therefore quick and easy to employ. This allows for the luffing capabilities to be used more often and as the need arises (instead of requiring prior planning to utilize the luffing capabilities). The stowable luffing jib may also be added to existing cranes, so as to make this added capability available to crane operators for a relatively low expense. The stowable luffing jib therefore presents a substantial advance in the art by providing luffing capabilities quickly, easily, and inexpensively.
A first embodiment of the invention is directed to a stowable luffing jib that comprises a base trunnion, a jib assembly, and a cable strut. The base trunnion is secured to the boom assembly. The base trunnion can be selectively placed into a stowed position and a deployed position. While the base trunnion is in the stowed position, the base trunnion is secured along the boom assembly substantially parallel with and adjacent to the boom assembly. While the base trunnion is in the deployed position, the base trunnion is secured to a distal end of the boom assembly and oriented substantially in line with the boom assembly. The jib assembly is secured to the base trunnion and configured to pivot in a substantially vertical plane. The cable strut secured to the base trunnion and configured to pivot in a substantially vertical plane to receive a luffing guy line so as to set an inclined angle of the cable strut relative to the base trunnion. The stowable luffing jib may also include a static-length guy line for keeping the cable strut and the jib assembly at a consistent relative angle.
A second embodiment is directed to a crane with an associated stowable luffing jib. The crane comprises a base, a boom assembly, a first winch, a second winch, and a stowable luffing jib. The boom assembly presents a proximal end and a distal end, and the proximal end of the boom assembly is rotatably secured to the base. The first winch selectively releases a load line to support a load. The second winch selectively releases a luffing guy line to set a declined angle. The stowable luffing jib is. associated with the boom assembly and configured to be selectively placed into a stowed orientation and a deployed orientation. The stowed orientation is defined by the stowable luffing jib being secured to a transportation bracket on an outer boom section of the boom assembly. The load line lifts the load via the distal end of the boom assembly while the stowable luffing jib is in the stowed orientation. The deployed orientation is defined by the stowable luffing jib being installed on the distal end and set at said declined angle, such that the load line lifts the load via the stowable luffing jib.
A third embodiment is directed to a method of adding luffing capabilities to a boom assembly of a crane, the method comprising the following steps: retracting the boom assembly such that an implement at a distal end of the boom assembly aligns with a stowable luffing jib; securing the stowable luffing jib to the implement; releasing the stowable luffing jib from a transportation bracket; swinging the stowable luffing jib from a stowed position to a deployed position, wherein the deployed orientation is defined by the stowable luffing jib being installed on the distal end such that the load line lifts the load via the stowable luffing jib; running a load line from a first winch through the stowable luffing jib such that it passes over a boom-jib sheave and a jib-load sheave; running a luffing guy line from a second winch through a cable strut of the stowable luffing jib; attaching a static-length guy line between a distal end of the cable strut and a distal end of a jib assembly of the stowable luffing jib; retracting the luffing guy line so as to set an inclined angle of the cable strut; raising the boom assembly to a certain boom angle; allowing the weight of the jib assembly to set a declined angle of the jib assembly relative to the boom angle; and securing a load to the load line.
Additional embodiments of the invention are directed to a method of installing the stowable luffing jib, a method of using the stowable luffing jib, a method of lifting an object supported by the stowable luffing jib, etc.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the invention will be apparent from the following detailed description of the embodiments and the accompanying drawing figures.
Embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:
The drawing figures do not limit the invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention.
The following detailed description references the accompanying drawings that illustrate specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense. The scope of the invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.
In this description, references to “one embodiment,” “an embodiment,” or “embodiments” mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate references to “one embodiment,” “an embodiment,” or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and/or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, the technology can include a variety of combinations and/or integrations of the embodiments described herein.
A crane 10 utilizing a stowable luffing jib 12, constructed in accordance with various embodiments of the invention, is shown in
In embodiments of the invention, a static-operations cab 24 is disposed on a first side 26 of the boom assembly 16 and the transportation bracket 18 for the stowable luffing jib 12 is disposed on a second side 28 of the boom assembly 16. This prevents the stowable luffing jib 12 from obstructing the operator's view of the boom assembly 16 and the load while the stowable luffing jib 12 is in the stowed position. As can be seen in
When the luffing capabilities are desired or required, the operator retracts the boom assembly 16. The operator then secures the stowable luffing jib 12 to the distal end of the boom assembly 16 and releases the stowable luffing jib 12 from the transportation bracket 18. The operator then swings the stowable luffing jib 12 from the stowed position to the deployed position. The deployed orientation is defined by the stowable luffing jib 12 being installed on the boom assembly such that the load line 42 lifts the load via the stowable luffing jib 12 (as illustrated in
It should be appreciated that, unlike in the prior art discussed above, the above steps are performed by the operator manually and/or with the assistance of hydraulic actuators on the crane 10. An extra assisting crane 10 is not required to deploy the stowable luffing jib 12. Further, the stowable luffing jib 12 is secured in the transportation bracket 18 during transportation to and from the worksite. In this way, an external transportation vehicle is not required to move the stowable luffing jib 12 to the worksite.
As discussed in depth below and best illustrated in
Returning to
In embodiments of the invention, each of the load line 42 and the luffing guy line 46 is a long steel cable, or other long metallic cable. The load line 42 is capable of supporting very large loads without breakage, failure, or substantial deformation. The luffing guy line 46 is capable of keeping the cable strut 34 aligned at a desired inclined angle while the stowable luffing jib 12 is under the weight of the load. An exemplary load line 42 or luffing guy line 46 can weigh approximately one pound per foot of length and be ⅝ inch in diameter. The load line 42 and the luffing guy line 46 are best illustrated in
The base 14 of the crane 10 is a selectively stabilized platform illustrated in
In embodiments of the invention such as illustrated in
The distal end 58 of the boom assembly 16 comprises an implement 60 for directing the load line 42 downward when the stowable luffing jib 12 is in the stowed position. The implement 60 may also perform other standard crane 10 functions. The stowable luffing jib 12 is selectively and pivotably secured to the implement 60 and/or another component of the distal end 58 of the boom assembly 16. In embodiments of the invention, the stowable luffing jib 12 is selectively secured to a trunnion interface segment 62 on the implement 60. The trunnion interface segment 62 is configured to allow the stowable luffing jib 12 to pivot therearound from the stowed position to the engaged position. While in the stowed position, the stowable luffing jib 12 is pivoted approximately 180 degrees such that the base trunnion 30 of the stowable luffing jib 12 is substantially pointed parallel to but in a reverse direction of the boom assembly 16, as illustrated in
The at least one inner boom section 22 is at least in part disposed within the outer boom section 20. The at least one inner boom section 22 telescopes to extend or retract into the outer boom section 20. In embodiments of the invention, the boom assembly 16 may comprise additional equipment including any of the following: power lines for the routing of hydraulic, pneumatic, or electrical power; communication wires for user-controls and sensors; and the like (not illustrated). In some embodiments of the invention, the boom assembly 16 comprises a first boom section that rotatably secured to the base 14 and a second boom section rotatably secured to a distal end of the first boom section (not illustrated). In still other boom assemblies, a combination of the telescoping and pivoting boom sections is utilized (not illustrated).
The at least one inner boom section 22 may telescope into a plurality of positions with respect to the outer boom section 20, including a fully retracted position, in which the length of the at least one inner boom section 22 is substantially inserted within the outer boom section 20 (as illustrated in
In embodiments of the invention, such as illustrated in
The boom assembly 16 of the crane 10 typically includes the first winch 40 and the second winch 44. The first winch 40 is typically disposed on or near the boom assembly 16 for selectively releasing the load line 42. The load line 42 supports the load from either the boom assembly 16 or the stowable luffing jib 12 (dependent upon which configuration is currently being utilized). The second winch 44 is typically disposed further from the boom assembly 16 than the first winch 40 is located for selectively releasing the luffing guy line 46. This is because the luffing guy line 46 is used to set the inclined angle of the cable strut 34, as discussed below. In some embodiments of the invention, the winch support 54 further comprises a counterweight 72 still further from the boom assembly 16. The counterweight 72 prevents damage to the crane 10 by leveling the load somewhat from before and behind the rotation point of the boom assembly 16.
In embodiments of the invention, the first winch 40 is substantially similar to the second winch 44. Each of the first winch 40 and the second winch 44 is disposed at the proximal end 56 of the boom assembly 16 so as to keep the first winch 40 and the second winch 44 aligned with the boom assembly 16 while the boom assembly 16 rotates about the base 14. Each winch 40, 44 includes a spool 74 and an associated hydraulic motor (not illustrated). The spool 74 includes two end caps 76 and a central section 78. The spool 74 rotates about a horizontal, lateral axis in response to actuation by the hydraulic motor.
The load line 42 is wrapped around the central section 78 of the first winch 40 and prevented from falling therefrom by the two end caps 76 of the first winch 40. Similarly, the luffing guy line 46 is wrapped around the central section 78 of the second winch 44 and prevented from falling therefrom by the two end caps 76 of the second winch 44. The hydraulic motor or other actuator spins each spool 74 independently so as to let out (i.e., elongate) or take in (i.e., shorten) the load line 42 and the luffing guy line 46, respectively.
The load line 42 includes a heavy terminal hook 80 disposed beyond the implement 60 and/or the jib assembly 32. The terminal hook 80 therefore pulls the load line 42 to elongate upon the hydraulic motor spinning the spool 74 in an elongating direction. The hydraulic motor takes in the load line 42 by spinning the spool 74 in a shortening direction. The hydraulic motor is therefore strong enough to lift the load by shortening the load line 42 while the load is attached to the load line 42 through either the implement 60 or the stowable luffing jib 12.
The components of the stowable luffing jib 12 will now be discussed in greater detail. As discussed above and best illustrated in
The base trunnion 30 is configured to be secured to the implement 60 at the distal end 58 of the boom assembly 16. As best illustrated in
The hinge segment 82 overlaps the trunnion interface segment 62 of the implement 60. As such, when the boom assembly 16 is fully retracted (e.g., slightly further than illustrated in
As the base trunnion 30 is moved from the stowed position to the deployed position, the lock segment 84 of the base trunnion 30 comes into contact with the trunnion interface segment 62 on the implement 60. The operator may then lock the base trunnion 30 to the implement 60. The locking of the base trunnion 30 may be done in the same manner in which the hinge segment 82 was secured, such as by placing a fastener, pivot bolt 98 or the like through the lock segment 84.
It should be appreciated that in embodiments of the invention, such as illustrated in
While the base trunnion 30 is in the deployed position, the body 88 of the base trunnion 30 is elongated and oriented substantially in line with the boom assembly 16. The body 88 presents a channel 100 into which the jib assembly 32 is pivotably secured via the jib pivot 90. It should also be noted that in embodiments of the invention, the jib pivot 90 and the strut pivot 92 are a common pivot. The elongation of the body 88 allows the jib assembly 32 to pivot away from the implement 60, such that the jib assembly 32 can pivot downward relative to the boom (i.e., at the declined angle, labeled angle θ1 in
The jib angle lock 94 secures the jib assembly 32 in a certain orientation relative to the base trunnion 30, and therefore relative to the boom assembly 16. The jib angle lock 94 allows the jib assembly 32 to function to as a standard static-angle jib. The jib angle lock 94 aligns four openings (two in the body 88 of the base trunnion 30 and two in the jib assembly 32). The operator then places a bolt 98 or other fastener through the aligned openings. The bolt 98 prevents the declined angle (i.e. the angle between the boom direction and the jib direction, how far declined the jib assembly 32 is from the original boom direction) from being adjusted thereafter without removing the bolt 98. In these instances the cable strut 34 is not utilized because the luffing capabilities will not be used. The cable strut 34 may be secured in an upward position, or allowed to rest along the jib assembly 32.
The boom-jib sheave 96 is configured to allow the load line 42 to pass thereover, as illustrated in
The boom-jib sheave 96 includes a pair of protrusions 102, an axle 104 rotatably disposed between the protrusions 102, and a wheel 106 disposed on the axle 104 (as illustrated in
In embodiments of the invention best illustrated in
In embodiments of the invention, the first jib section 110 of the jib assembly 32 is elongated so as to present a proximal end 118 and a distal end 120. The proximal end 118 of the first jib section 110 is pivotably secured to the base trunnion 30 at the trunnion interface 108. The trunnion interface 108 of the first jib section 110 is disposed within the channel 100 of the base trunnion 30. The trunnion interface 108 presents an opening through which the pivot bolt 98 (or other fastener is disposed). The pivot bolt 98 allows the first jib section 110 (and by extension, the entire jib assembly 32) to pivot downward from aligned with the boom assembly 16 to the angle θ1 of
In embodiments of the invention, the second jib section 112 is also elongated so as to present a proximal end 122 and a distal end 124. The proximal end 122 of the second jib section 112 is secured to the distal end 120 of the first jib section 110, as discussed below. The jib-load sheave 116 is disposed at the distal end 124 of the second jib section 112 to redirect the load line 42 downward toward the load. The second jib section 112 therefore furthers the reach of the jib assembly 32. The first jib section 110 is pivotably secured to the second jib section 112 at the section interface 114.
As best illustrated in
When in the stowed position as illustrated in
In embodiments of the invention, both the first jib section 110 and the second jib section 112 are tapered such that the respective distal ends 120, 124 present a smaller cross-sectional area (about a vertical cross-section) than their respective proximal ends 118, 122 (as best illustrated in
In other embodiments, not illustrated, the second jib section 112 telescopes within the first jib section 110. In still other embodiments, the jib assembly 32 comprises a single jib section. In yet further embodiments, the first jib section 110 includes an alternate jib-load sheave 116 (not illustrated) at the distal end 120 of the first jib section 110, such that the first jib section 110 can be utilized without the second jib section 112 if a shorter jib is desired by the operator.
In still other embodiments, not illustrated the jib assembly 32 further comprises a third jib section, a fourth jib section, etc. The third jib section and/or the fourth jib section allows the operator even greater customization in selecting the length of the jib assembly 32 that is most appropriate for the given task. The second jib section 112 may be secured to the third jib section via a section interface 114 that is similar to the section interface 114 securing the second jib section 112 to the first jib section 110.
As best illustrated in
The jib-load sheave 116 may also include a distal static-line anchor 132 disposed at the distal end 124 of the second jib section 112 (as illustrated in
Returning to
In embodiments of the invention, the cable strut 34 comprises a first-side segment 146, a second-side segment 148, and at least one traversing support 150. The first-side segment 146 and the second-side segment 148 are elongated so as to span from the proximal end 138 to the distal end 140. The traversing supports 150 are disposed between the first-side segment 146 and the second-side segment 148 so as to provide lateral support. The load line 42 therefore passes between the first-side segment 146 and the second-side segment 148 and below the traversing support 150. In other embodiments of the invention, the load line 42 may pass through an opening in the cable strut 34 (not illustrated).
The luffing guy line 46 is configured to set the inclined angle of the cable strut 34 relative to the boom assembly 16. By shortening the luffing guy line 46, the luffing sheave 142 is pulled downward (i.e., toward the second winch 44). This increases the inclined angle by pivoting the distal end 140 of the cable strut 34 away from being aligned with the boom assembly 16. The second winch 44 therefore elongates and shortens the luffing guy line 46 so as to set the inclined angle.
The static-length guy line 36 is configured to run from the distal end 140 of the cable strut 34 to the distal end 124 of the second jib section 112 (or of the jib assembly 32 generally), as illustrated in
The stowable luffing jib 12 is returned from the deployed position to the stowed position by reversing the deployment steps. However, lowering the cable strut 34 back down level with the first jib section 110 requires additional assistance beyond the operator's manual manipulations. While the cable strut 34 was pulled to vertical via the second winch 44 shortening the luffing guy line 46, reversing this process will not drop the cable strut 34 back down flat (and even if it could, it would crash down violently). In embodiments of the invention, the stowable luffing jib 12 may include a hydraulic actuator to gently lower the cable strut 34 back down to horizontal (not illustrated). In other embodiments, the operator may reroute the load line 42 about the jib-load sheave 116 so as to secure to the distal end 140 of the cable strut 34. In this way, the operator can manipulate the first winch 40 and the second winch 44 in concert so as to lower the cable strut 34 back down. In still other embodiments, an assisting crane 10 may lower the cable strut 34.
As discussed above, the stowable luffing jib 12 is configured to be utilized in a luffing orientation and a standard orientation. The luffing orientation has been discussed above, such that second winch 44 can set by the second winch 44 adjusting the length of luffing guy line 46 to the cable strut 34. Thus, the declined angle is variable and varied as desired to control the load. This allows the crane 10 to lift the load in a luffing configuration such that the crane 10 can push the load farther (or pull the load closer) to the crane 10 while keeping the load substantially level with the ground.
In the standard orientation the jib is kept at a constant angle relative to the boom assembly 16. This may be accomplished by placing a pivot bolt 98 through the jib angle lock 94. This keeps the declined angle static, such that it can only be changed by removing the pivot bolt 98. In embodiments of the invention, there may be multiple jib angle locks 94 such that the operator can select any of several static declined angles. It should also be appreciated that the operator may be required to ascend a ladder or aerial device to reach the distal end 58 of the boom assembly 16 so as to set this declined angle.
In embodiments of the invention, the stowable luffing jib 12 further comprises an angle sensor 152, as illustrated in
The computer control system instructs the first winch 40, the second winch 44, and the boom assembly 16 to perform various operations. As such, the computer control system can manipulate the stowable luffing jib 12 despite having no direct control over the stowable luffing jib 12. In embodiments of the invention in which the stowable luffing jib 12 is added to an existing crane 10, the computer control system may be updated or edited so as to allow the computer control system to successfully control the stowable luffing jib 12 via the various components.
A method of installing the stowable luffing jib 12 onto the crane 10 will now be discussed. The method comprises the following steps: installing the transportation bracket 18 onto the second side 28 of the boom assembly 16 (i.e., opposite the static-operations cab 24); installing the stowable luffing jib 12 into the transportation bracket 18; and ensuring that the hinge segment 82 will align with the implement 60 of the boom assembly 16 while the boom assembly 16 is in a fully retracted (or substantially fully retracted) position. The method may further comprise the steps of installing a second winch 44 onto the winch support 54; wrapping the luffing guy line 46 around the second winch 44; and providing for control of the second winch 44 from the computer control system.
A method of using the method of adding luffing capabilities to at the boom assembly 16 of the crane 10 will now be discussed. The method comprises the following steps: retracting the boom assembly 16 such that the implement 60 at the distal end 58 of the boom assembly 16 aligns with the stowable luffing jib 12; securing the stowable luffing jib 12 to the implement 60; releasing the stowable luffing jib 12 from a transportation bracket 18; swinging the stowable luffing jib 12 from a stowed position to a deployed position, wherein the deployed orientation is defined by the stowable luffing jib 12 being installed on the distal end 58 such that the load line 42 lifts the load via the stowable luffing jib 12; running a load line 42 from the first winch 40 through the stowable luffing jib 12 such that it passes over the boom-jib sheave 96 and a jib-load sheave 116; running the luffing guy line 46 from the second winch 44 through the cable strut 34 of the stowable luffing jib 12; attaching the static-length guy line 36 between the distal end 140 of the cable strut 34 and the distal end 124 of the second jib section 112 of the stowable luffing jib 12; retracting the luffing guy line 46 so as to set an inclined angle of the cable strut 34; removing the jib angle lock 94; raising the boom assembly 16 to a certain boom angle; allowing the weight of the jib assembly 32 to set a declined angle of the jib assembly 32 relative to the boom angle; and securing a load to the load line 42.
A method of lighting a load using the crane 10 with the stowable luffing jib 12 installed thereon will be briefly discussed. The method comprises the following steps: securing the load to the load line 42; operating the first winch 40 to manipulate the length of the load line 42; operating the boom assembly 16 to manipulate the orientation of the boom assembly 16 relative to the ground; operating the second winch 44 to manipulate the inclined angle of the cable strut 34; and allowing the static cable 36 to therefore adjust the declined angle of the jib assembly 32. The method may include operating the first winch 40, the boom assembly 16, and the second winch 44 in concert such that the load remains substantially level with the ground and travels toward or away from the base 14 of the crane 10. The method may also include operating the second winch 44 so as to keep the inclined angle constant while the boom assembly 16 is being pivoted upward or downward.
Although the invention has been described with reference to the embodiments illustrated in the attached drawing figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims.