Self-erecting mobile crane

In a crane, said crane having a carbody supported on a generally horizontal surface for forward and rearward movement along its longitudinal axis by a pair of traction assemblies situated on either side of said longitudinal carbody axis, a machinery platform rotatably mounted on the carbody for swinging movement about a vertical machinery platform axis, means for rotating said platform, a support ring supported on a horizontal surface and providing a horizontal ring path in concentric relation to the vertical platform axis, a boom foot carrier pivotably mounted at its inner end to a forward portion of the machinery platform on a horizontal boom foot carrier pivot axis perpendicular to the longitudinal carbody axis and supported at its outer end for movement along the ring path, a boom having a boom foot pivotably mounted to an outer end portion of the carrier on a boom foot pivot axis parallel to the boom foot carrier pivot axis, a mast having a mast foot pivotably mounted to the carrier on a pivot axis parallel to the boom foot carrier pivot axis, a machinery platform first counterweight supported on a rearward portion of the machinery platform, a gantry mounted to the machinery platform to extend generally above the first counterweight, a first boom suspension linkage between upper end portions of the mast and the boom, means for varying the length of said first suspension linkage, a second boom suspension linkage between an upper portion of the gantry and an upper portion of the mast, load handling means, and means including a load line extending over the point of the boom for handling a load on said load handling means, wherein the improvement comprises

• A. a travel strut and mast erection assembly extends upwardly from the platform and the carrier, said assembly including a rigid compression strut pivotably mounted at a lower end thereof adjacent the boom foot carrier pivot axis on an axis parallel to said boom foot carrier pivot axis, and including boom foot carrier tension pendant means connected between an upper end of the compression strut and an outer end portion of the boom foot carrier, the length of the boom foot carrier tension pendant means being such that pivotal movement of said compression strut from a lowered forward position toward an upright position is arrested at such upright position by tensioning said carrier tension pendant means;
• B. a boom foot carrier suspension assembly is connected between an upper portion of the gantry and an upper end portion of the travel strut, said carrier suspension assembly including a third suspension linkage connected at its inner end to the gantry, means for varying the length of said third suspension linkage, and boom foot carrier suspension means connected between an outer end of the third suspension linkage and an upper portion of the compression strut;
• C. a mast suspension assembly is connected between an upper portion of the gantry and an upper portion of the mast, said mast suspension assembly including said third suspension linkage connected at its inner end to the gantry, said means for varying the length of said third suspension linkage, and mast suspension pendant means connected between the outer end of the third suspension linkage and an upper portion of the mast;
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• D. said second boom suspension linkage includes second boom suspension pendant means connected at its upper end to the upper end portion of the mast and includes second boom suspension connecting means operable to connect a lower end of said second boom suspension pendant means to the gantry.

In a crane, said crane having a carbody supported on a generally horizontal surface for forward and rearward movement along its longitudinal axis by a pair of traction assemblies situated on either side of said longitudinal carbody axis, a machinery platform rotatably mounted on the carbody for swinging movement about a vertical machinery platform axis, means for rotating said platform, a support ring supported on a horizontal surface and providing a horizontal ring path in concentric relation to the vertical platform axis, a boom foot carrier pivotably mounted at its inner end to a forward portion of the machinery platform on a horizontal boom foot carrier pivot axis perpendicular to the longitudinal carbody axis and supported at its outer end for movement along the ring path, a boom having a boom foot pivotably mounted to an outer end portion of the carrier on a boom foot pivot axis parallel to the boom foot carrier pivot axis, a mast having a mast foot pivotably mounted to the carrier on a pivot axis parallel to the boom foot carrier pivot axis, a first counterweight supported to rotate with the machinery platform, a gantry mounted to a rearward portion of the machinery platform, a first boom suspension linkage between upper end portions of the mast and the boom, means for varying the length of said first suspension linkage, a second boom suspension linkage between the first counterweight and an upper portion of the mast, load handling means, and means including a load line extending over the point of the boom for handling a load on said load handling means, wherein the improvement comprises:

• A. a strut assembly extends upwardly from the platform and the carrier, said strut assembly including a rigid compression strut pivotably mounted at a lower end thereof adjacent the boom foot carrier pivot axis on an axis parallel to the carrier pivot axis, and including boom foot carrier tension pendant means connected between an upper end of the compression strut and an outer end portion of the boom foot carrier, the length of said boom foot carrier tension pendant means being such that pivotal movement of said compression strut from a lowered forward position toward an upright position is arrested at such upright position by tensioning said carrier tension pendant means;
• B. a boom foot carrier suspension assembly is connected between an upper portion of the gantry and an upper end portion of the compression strut, said carrier suspension assembly including a third suspension linkage connected at its inner end to the gantry, means for varying the length of said third linkage, and boom foot carrier suspension means connected between an outer end of the third suspension linkage and an upper portion of the compression strut;
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• C. said second boom suspension linkage includes second boom suspension pendant means connected at its upper end to an upper end portion of the mast and includes second boom suspension connecting means operable to connect a lower end of second boom suspension pendant means to said gantry and counterweight.