Endless chain drive for telescopic jib sections
AssigneeColes Cranes Limited
InventorKarl M. Gyomrey
Life of this patent
Estimating the term…
Abstract
A crane of the telescopic jib type wherein the telescopic jib sections are driven for outward and inward telescopic movement by a chain cable or the like which is connected to the jib sections and movement of which in one direction drives the sections outwardly and movement of which in the other direction drives the sections inwardly. This enables a simple and relatively cheap drive means to be employed.
Claims11
A telescopically extensible boom crane comprising:
- a base boom section mounted to a crane platform;
- an intermediate boom sectionry telescopically mounted within said base boom section, said sectionry comprising at least one intermediate boom section;
- a head boom section telescopically mounted within said intermediate sectionry;
- flexible boom section extension means including a closed loop extending the length of said intermediate sectionry between an inner loop guide means mounted to a base end of said intermediate sectionry and an outer loop guide means mounted to a head end of said intermediate sectionry;
- means for securing said loop to said head section and to said base section at fixture points;
- and
- means mounted to said intermediate sectionry for driving said loop whereby actuation of said drive means to drive said loop extends or retracts said boom.
A telescopically extensible boom crane comprising a base boom section pivotally mounted for luffing from a crane platform, a derrick mast mounted to said platform, tie means extending from said mast to said boom for luffing said boom, said boom further comprising intermediate boom sectionry telescopically mounted within said base boom section, said sectionry comprising at least one intermediate boom section, a head boom section telescopically mounted within said intermediate sectionry, flexible boom extension means formed as a closed loop extending the length of said intermediate sectionry between intermediate inner loop guide means mounted to the base of said intermediate sectionry, outer loop guide means mounted to the head of said intermediate sectionry, said head section and said base section being connected to said loop at points between said inner and outer loop guide means, drive means drivingly engageable with said loop at a point along a path defined by a portion of each said guide means and lines interconnecting said portions, whereby actuation of said drive means so as to drive said loop extends or retracts said boom.
A method of extending the boom of a telescopically extensible boom crane, said boom comprising a base boom section mounted to a crane platform, intermediate boom sectionry telescopically mounted within said base boom section, said sectionry including at least one intermediate boom section, a head section telescopically mounted within said intermediate sectionry, the method comprising the steps of:
- forming a flexible boom section extension means in a closed loop extending only the length of said intermediate sectionry and guided at each end of said intermediate sectionry;
- fixing said loop at a first position along said loop to a foot end of said head section and at a second position along said loop to a head end of said base section;
- driving said loop to telescope said boom sections;
- and braking said loop to hold said boom at a chosen telescoped position.
Dependencies are inferred from the claim text.