# US 7,611,022 B2 · Upper block > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,022 B2 - Document ID: US7611022B2 - Status: Granted - Kind: B2 - Application number: 11/869,808 - Filed: 2007-10-10 - Published: 2008-01-31 - Granted: 2009-11-03 - Earliest claimed: 2004-09-08 - Assignees: MHE Technologies, Inc. - Inventors: Steven K. Waisanen - Web page: https://patentgrep.com/patent/US7611022B2 ## CPC - B66C 15/065: {electrical} - B66D 1/58: responsive to excess of load - B66C: CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES ({specially adapted for lifting invalids A61G7/10;} rope, cable, or chain winding mechanisms, braking or detent devices therefor B66D; specially adapted for nuclear reactors G21) - B66D: CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS (winding or unwinding ropes or cables for feeding or storage purposes B65H; rope or cable winding or unwinding mechanisms for lifts B66B) ## Abstract A crane having an upper block, a lower block, a drum, and two ropes. The upper block includes an equalizer having a yoke to which the ropes are connected. The connections between the ropes and the yoke include load cells that measure the forces carried by each of the ropes. The upper block includes a fail-safe system that prevents failure of the upper block in overload conditions. ## Claims ### Claim 1 A crane having a drum, an upper block, and a lower block, the crane comprising: a support wall; a first rope having a first rope end; a second rope having a second rope end; an equalizer yoke pivotally mounted to the support wall by a pivot pin and having two load pins, each rope end being coupled to one of the load pins; wherein each of the load pins includes a load cell which measures forces carried by the coupled one of the first and second ropes; wherein the first and second rope ends are substantially parallel to one another in a direction substantially perpendicular to a line running through the two load pins; a yoke pin mounted to the yoke and extending through a slot in the support wall; wherein the yoke pin is spaced apart from the pivot pin so that the yoke pin pivots about the pivot pin and moves along the slot when the yoke pivots relative to the support wall to equalize loads between the first and second ropes; and at least one damper extending between the yoke pin and the support wall to dampen motion of the yoke by providing resistance on the yoke pin when the yoke pivots relative to the support wall due to failure of one the first and second ropes. ### Claim 2 (depends on 1) The crane according to claim 1, wherein the at least one damper comprises a pneumatic cylinder. ### Claim 3 (depends on 1) The crane according to claim 1, wherein the support wall is pivotably supported by the upper block. ### Claim 4 (depends on 1) The crane according to claim 1, wherein two of the dampers extend between the yoke pin and the support wall. ### Claim 5 (depends on 4) The crane according to claim 4, wherein the two dampers each comprise a pneumatic cylinder. ### Claim 6 (depends on 1) The crane according to claim 1, further comprising another yoke pin mounted to the yoke and extending through another slot in the support wall, and wherein the another yoke pin is spaced apart from the pivot pin so that the another yoke pin pivots about the pivot pin and moves along the another slot when the yoke pivots relative to the support wall to equalize loads between the first and second ropes. ### Claim 7 (depends on 6) The crane according to claim 6, further comprising at least one another damper extending between the another yoke pin and the support wall to dampen motion of the yoke by providing resistance on the another yoke pin when the yoke pivots relative to the support wall due to failure of one the first and second ropes. ### Claim 8 (depends on 7) The crane according to claim 7, wherein two of the dampers extend between the yoke pin and the support wall and two of the another dampers extend between the another yoke pin and the support wall. ### Claim 9 (depends on 8) The crane according to claim 8, wherein the two dampers each comprise a pneumatic cylinder. ### Claim 10 (depends on 6) The crane according to claim 6, wherein the yoke pin and the another yoke pin are located on opposite sides of the pivot pin. ### Claim 11 An equalizer for a crane having a drum, a lower block, an upper block, and at least two rope ends, the equalizer comprising: a support wall; an equalizer yoke pivotally coupled to the support wall and including two load pins, each rope end being coupled to one of the load pins; wherein each of the load pins includes a load cell which measures forces carried by the coupled one of the rope ends; a yoke pin mounted to the yoke and extending through a slot in the support wall; wherein the yoke pin is spaced apart from the pivot pin so that the yoke pin pivots about the pivot pin and moves along the slot when the yoke pivots relative to the support wall to equalize loads between the rope ends; and at least one damper extending between the yoke pin and the support wall to dampen motion of the yoke by providing resistance on the yoke in when the yoke pivots relative to the support wall due to failure of one the rope ends. ### Claim 12 (depends on 11) The crane according to claim 11, wherein the at least one damper comprises a pneumatic cylinder. ### Claim 13 (depends on 11) The crane according to claim 11, wherein the support wall is pivotably supported by the upper block. ### Claim 14 (depends on 11) The crane according to claim 11, wherein two of the dampers extend between the yoke pin and the support wall. ### Claim 15 (depends on 14) The crane according to claim 14, wherein the two dampers each comprise a pneumatic cylinder. ### Claim 16 (depends on 11) The crane according to claim 11, further comprising another yoke pin mounted to the yoke and extending through another slot in the support wall, and wherein the another yoke pin is spaced apart from the pivot pin so that the another yoke pin pivots about the pivot pin and moves along the another slot when the yoke pivots relative to the support wall to equalize loads between the first and second ropes. ### Claim 17 (depends on 16) The crane according to claim 16, further comprising at least one another damper extending between the another yoke pin and the support wall to dampen motion of the yoke by providing resistance on the another yoke pin when the yoke pivots relative to the support wall due to failure of one the first and second ropes. ### Claim 18 (depends on 17) The crane according to claim 17, wherein two of the dampers extend between the yoke pin and the support wall and two of the another dampers extend between the another yoke pin and the support wall. ### Claim 19 (depends on 18) The crane according to claim 18, wherein the two dampers each comprise a pneumatic cylinder. ### Claim 20 (depends on 16) The crane according to claim 16, wherein the yoke pin and the another yoke pin are located on opposite sides of the pivot pin.