FOLDING JIB MAIN STRUT AND TRANSPORTABLE REEVED STRUT CAPS

• US 20100243595A1
• Filed: 03/24/2010
• Published: 09/30/2010
• Est. Priority Date: 03/31/2009
• Status: Active Grant

• Current Assignee: Manitowoc Cranes LLC (The Manitowoc Company, Inc.)
• Original Assignee: Manitowoc Cranes LLC (The Manitowoc Company, Inc.)
• Inventors: Walker, Robert J., Wanek, Michael J.
• Granted Patent: US 8,839,966 B2
• Time in Patent Office: Days
• US Class Current: 212/294
• CPC Class Codes: B66C 23/26 for use on building sites; constructed, e.g. with separable parts, to facilitate rapid assembly or dismantling, for operation at successively higher levels, for transport by road or rail with supporting couples provided by walls or buildings B66C23/20; mounted on vehicles B66C23/36; jib constructions B66C23/64
• CPC Class Codes: B66C 23/365 dismantable into smaller units for transport purposes
• CPC Class Codes: B66C 23/82 Luffing gear

Abstract

A method of assembling a mobile lift crane that includes, during operation, i) a rotating bed having attached thereto a luffing jib hoist drum and line, and a rigging winch drum and line, ii) a boom pivotally mounted on the rotating bed, iii) a luffing jib pivotally mounted to the end of the boom, iv) a first strut also pivotally connected to the end of the boom, and v) a second strut connected to the boom below the connection point of the first strut, the method including: a) pivotally connecting the first strut to the end of the boom; b) pivotally connecting a first section of the second strut near the top of the boom; c) connecting the rigging winch line to the top of the first section; d) pivotally attaching a second section of the second strut to the first section such that the second section lies folded onto the first section, forming a folded second strut; and e) lifting the second section while retracting the rigging winch line to thereby bring the first and second sections into alignment with each other.

Claims

1. A method of assembling a mobile lift crane, the lift crane comprising, during operation, i) a rotating bed having attached thereto a luffing jib hoist drum and line, and a rigging winch drum and line, ii) a boom pivotally mounted on the rotating bed, iii) a luffing jib pivotally mounted to the end of the boom, iv) a first strut also pivotally connected to the end of the boom, and v) a second strut connected to the boom below the connection point of the first strut, the method comprising:

a) pivotally connecting the first strut to the end of the boom;

b) pivotally connecting a first section of the second strut near the top of the boom;

c) connecting the rigging winch line to the top of the first section;

d) pivotally attaching a second section of the second strut to the first section such that the second section lies folded onto the first section, forming a folded second strut; and

e) lifting the second section while retracting the rigging winch line to thereby bring the first and second sections into alignment with each other.

2. The method of claim 1, wherein the lift crane, during operation, further comprises vi) a strut stop connected between the second strut and the boom, and wherein the first and second struts have respective first and second caps attached thereto, each having a plurality of sheaves, the method further comprising:

reeving the luffing jib hoist line through the plurality of sheaves in each of the first and second strut caps; and

connecting the strut stop between the boom and the first section of the second strut stop.

3. The method of claim 2, wherein reeving the luffing jib hoist line comprises connecting a dead end of the luffing jib hoist line to one of the strut caps or one of the struts, the method further comprising:

pinning off at least one connection between the first and second sections of the second strut; and

detaching the rigging winch line from the first section.

4. The method of claim 3, wherein the lift crane, during operation, further comprises vii) at least one jib backstay strap connected between the bottom of the boom and the second cap attached to the second strut, the method further comprising:

I) before step (e), connecting the reeved second cap of the second strut to the top of the second section, wherein lifting the second section comprises lifting, with an assist crane, a raising pendant attached to a strut top of the second section while retracting the rigging winch line to bring the first and second sections into alignment with each other; and

II) before connection of the second cap to the second strut, connecting sections of the at least one jib backstay strap to the second strut cap, and connecting the sections of the at least one jib backstay strap of the second strut cap to a plurality of additional sections of the at least one jib backstay strap which are attached to the bottom of the boom.

5. A method of assembling a mobile lift crane, the lift crane comprising, during operation, i) a rotating bed, ii) a boom pivotally mounted on the rotating bed, iii) a luffing jib pivotally mounted to the end of the boom;

iv) a first strut also pivotally connected to the end of the boom, the first strut including a first strut cap having sheaves, and v) a second strut connected to the boom below the connection point of the first strut, the second strut including a second strut cap having sheaves, the method comprising;

a) connecting the first strut, together with the first and second strut caps reeved with a first line, to the end of the boom;

b) connecting a second line to an end of the first line, the second line being wound around a rotatable drum mounted on an immobilized drum frame; and

c) removing the first line to thereby pull the second line through the sheaves to reeve the first and second strut caps with the second line.

6. The method of claim 5, wherein the first strut cap is connected to a distal end of the first strut while being transported, wherein step b) is executed before step a), further comprising prior to assembling the mobile lift crane:

transporting to a job site the second strut cap, disconnected from a distal end of the second strut and reeved together with the first strut cap using the first line; and

transporting the first and second struts to the job site.

7. The method of claim 5, wherein the lift crane, during operation, further comprises vi) a luffing jib hoist drum and line, and vii) a rigging winch drum and line, wherein each drum is attached to the rotating bed, wherein the second line comprises the jib hoist line, and wherein removing the first line comprises:

connecting the rigging winch line to a second end of the first line;

retracting the rigging winch line to remove the first line from the plurality of sheaves of the strut caps while reeving the luffing jib hoist line;

disconnecting the luffing jib hoist line from the first line; and

connecting a dead end of the luffing jib hoist line to one of the struts or strut caps.

8. The method of claim 5, wherein the lift crane, during operation, further comprises vi) a luffing jib hoist drum and line, and vii) a rigging winch drum and line, wherein each drum is attached to the rotating bed, and wherein the second line comprises the rigging winch line, the method further comprising:

connecting the luffing jib hoist line to the end of the rigging winch line;

retracting the rigging winch line to reeve the plurality of sheaves of the strut caps with the luffing jib hoist line;

disconnecting the luffing jib hoist line from the rigging winch line; and

connecting a dead end of the luffing jib hoist line to one of the struts or strut caps.

9. The method of claim 5, wherein the lift crane, during operation, further comprises vi) a strut stop connected between the main strut and the boom, vii) a luffing jib hoist drum and line, and viii) a rigging winch drum and line, wherein each drum is attached to the rotating bed, and wherein the second line comprises the jib hoist line, the method further comprising:

d) pivotally connecting a first section of the second strut near the top of the boom;

e) connecting the strut stop between the boom and the first section;

f) attaching the rigging winch line to the top of the first section;

g) pivotally attaching a second section of the second strut to the first section such that the second section lies folded onto the first section, forming a folded second strut;

h) connecting sections of at least one jib backstay strap to the second strut cap;

i) lifting the second strut cap with an assist crane while paying out the luffing jib hoist line, to raise the second strut cap vertically and create slack between the reeved first and second caps; and

j) pinning the second strut cap to the top of the second section.

10. The method of claim 9, further comprising:

positioning the luffing jib hoist line off to a side of the first strut before step d); and

laying the luffing jib hoist line over the second section of the second strut before steps i) and j).

11. The method of claim 9, further comprising:

selecting the number of the sections of the at least one jib backstay strap depending on the length of the boom.

12. The method of claim 9, further comprising:

connecting the sections of the at least one jib backstay strap to a plurality of additional sections of the at least one jib backstay strap that are attached to the bottom of the boom;

connecting a line of the assist crane to a raising pendant attached to the end of the second section;

while raising the second section with the assist crane connected to the raising pendant, retracting the rigging winch line to bring the first and second sections into alignment with each other;

pinning off at least one connection between the first and second sections of the second strut;

disconnecting the rigging winch line and the assist crane line;

connecting a plurality of sections of at least one jib support strap between the jib strut and the top of the luffing jib; and

connecting the bottom of the luffing jib to the top of the boom.

13. A method of disassembling and transporting a mobile lift crane from a job site, the lift crane comprising, during operation, i) a pair of luffing jib struts;

ii) a cap attached to each strut, each having a plurality of sheaves, and iii) a luffing jib hoist line reeved through the plurality of sheaves of each strut cap, the method comprising;

a) detaching at least one strut cap from one of the luffing jib struts;

b) retracting the luffing jib hoist line until the strut caps are adjacent to each other;

c) retaining the strut caps adjacent to each other such that they remain reeved to each other; and

d) transporting the pair of reeved caps together from the job site.

14. The method of claim 13, wherein the pair of luffing jib struts comprise first and second struts that are pivotally connected to a boom of the lift crane during operation, wherein the luffing jib hoist line dead ends on one of the struts or strut caps, and wherein the second strut cap is detached and connected to the first strut cap or to a strut top of the first strut, the method further comprising:

e) connecting a first line to the dead end of the luffing jib hoist line;

f) retracting the luffing jib hoist line until free of the strut caps and the first line is reeved within the plurality of sheaves of the first and second strut caps; and

g) transporting the first strut and the reeved first and second strut caps together from the job site.

15. The method of claim 13, wherein the strut caps are connected to each other while being transported from the job site.

16. The method of claim 13, wherein the luffing jib hoist line dead ends on one of the strut caps, and wherein both of the strut caps are removed from their respective struts, the method further comprising:

e) removing the luffing jib hoist line from a plurality of wire guides attached to a boom of the crane, wherein the wire guides are designed for release of the luffing jib hoist line without being threaded therethrough;

f) retracting the luffing jib hoist line until the pair of strut caps are adjacent a luffing jib hoist drum of the lift crane;

g) attaching the connected caps to a frame of the luffing jib hoist drum; and

h) transporting the pair of reeved caps together with the luffing jib hoist drum from the job site.

17. A method of transporting and assembling a mobile lift crane, the lift crane comprising, during operation, i) a rotating bed, ii) a boom pivotally mounted on the rotating bed, iii) a luffing jib pivotally mounted to the end of the boom, iv) a first strut also pivotally connected to the end of the boom, the first strut including a first strut cap, v) a second strut connected to the boom below the connection point of the first strut, the second strut including a second strut cap, and vi) a luffing jib hoist drum and line, the luffing jib hoist drum attached to the rotating bed, the method comprising:

a) transporting to a job site the first and second strut caps, detached from the first and second struts, with the luffing jib hoist drum, wherein the luffing jib hoist line is reeved through sheaves of the first and second strut caps;

b) transporting the first and second struts to the job site;

c) connecting the first strut cap, while reeved to the second strut cap, to the end of the first strut; and

d) connecting the first strut to the end of the boom.

18. The method of claim 17, wherein step d) is executed before step c).

19. A strut cap assembly comprising:

a) first and second removable jib strut caps, each comprising;

i) a plurality of sheaves;

ii) a pair of side brackets each having a first aperture through which to detachably attach the strut cap to a first luffing jib strut of a mobile lift crane; and

iii) a first protrusion having a first aperture through which to be pinned to the other strut cap or to a strut top of a second luffing jib strut; and

b) a wire rope reeved through the plurality of sheaves of each of the first and second strut caps.

20. The strut cap assembly of claim 19, the assembly further comprising:

a strut having attached at the top thereof the first strut cap, the strut including a pair of second protrusions attached to a side thereof near the first strut cap, the pair of second protrusions having second apertures, wherein the side brackets of the second strut cap are attached to the second protrusions through the first and second apertures, wherein the first protrusion of the second strut cap is attached to the strut top through the first aperture.