Programme controlled hydraulic loading crane

• US 4,037,742 A
• Filed: 10/07/1975
• Issued: 07/26/1977
• Est. Priority Date: 10/08/1974
• Status: Expired due to Term

• Current Assignee: Hiab-Foco AB
• Original Assignee: Hiab-Foco AB
• Inventors: Gustafsson, Hans Eric Karl
• Primary Examiner(s): Makay, Albert J.
• Assistant Examiner(s): Weaver, Ross
• Application Number:
  US05/620,267
• Time in Patent Office: 658 Days
• Field of Search: 214/762-764, 214/DIG. 2, 214/1 CM, 214/141, 214/138 R, 214/11 C, 214/761, 235/151.11 R, 235/151.11 M, 212/39 R, 212/39 A, 212/39 MS, 212/39 P, 340/267 C, 104/38, 37/DIG. 1
• US Class Current: 414/694
• CPC Class Codes: B66C 13/48 Automatic control of crane drives for producing a single or repeated working cycle; Programme control
• CPC Class Codes: G05B 19/427 Teaching successive positions by tracking the position of a joystick or handle to control the positioning servo of the tool head, master-slave control G05B19/423 takes precedence
• CPC Class Codes: G05B 2219/41309 Hydraulic or pneumatic drive

Abstract

In a hydraulically operated loading crane of the kind comprising a rotatable crane post, an inner crane boom pivotally mounted at the upper end of said post, a jib pivotally mounted to said boom, and an extension boom mounted for longitudinal displacement relative to said jib and supporting at its outer end a load hoisting tool, an electronically programmable control system incorporating encoders capable of measuring the relative movements of the crane parts and arranged to store the measured values in a memory, and a comparator means arranged to compare signals representing pre-programmed patterns of movements with the signals received from said encoders so as to effect feeding of the required quantity of pressurized medium to the various hydraulic means to obtain the desired, pre-programmed patterns of movements.

Claims

1. An improved hydraulic loading crane comprising crane parts including a hydraulically rotatable crane post, an inner crane boom mounted at the upper end of said post for hydraulically operated pivotal movement in a vertical plane, a jib mounted at the outer end of said inner boom for hydraulically operated pivotal movement in a vertical plane, said jib provided with means for lifting a load, and an electronically programmed control system comprising a memory, and a plurality of electrical encoders mounted on said crane and arranged, upon movement of said crane parts from a starting position to an end position and back, to register and store in said memory the change of positions between said crane parts which are movable relative to one another, a servo valve, and a comprising unit inserted between said memory and said servo valve and arranged, upon reading of said memory during the operation of said crane to compare signals stored in said memory with signals which are continuously emitted by said encoders to open said servo valve to values corresponding to the difference between said continuously incoming signals and the signals emitted from said memory for the purpose of feeding a corresponding required quantity of pressurized medium to the various hydraulic means for the purpose of obtaining the pre-programmed movements of said crane parts, said electrical encoders being arranged to register the change of angular positions between any one of said crane parts and said loading crane being further provided with means for turning said crane post comprising a first hydraulically operated rack arranged for reciprocal movement, a cog wheel disposed at the lower end of said post, said first rack cooperating with said cog wheel, said first rack provided with a second rack extending in the longitudinal direction of said first rack, a shaft arranged to drive one of said encoders, and a cog wheel mounted at one end of said shaft, said second rack engaging the teeth of said cog wheel.

2. An improved hydraulic loading crane as claimed in claim 1 wherein said electrical encoders are potentiometers.

3. An improved hydraulic loading crane, comprising crane parts including a hydraulically rotatable crane post, an inner crane boom mounted at the upper end of said post for hydraulically operated pivotal movement in a vertical plane, a jib mounted at the outer end of said inner boom for hydraulically operated pivotal movement in a vertical plane, an extension boom mounted on said jib for displacement in the longitudinal direction of said jib, said extension boom provided an its outer end with means for lifting a load and an electronically programmed control system comprising a memory, and a plurality of electrical encoders mounted on said crane and arranged, upon movement of said crane parts from a starting position to an end position and back, to register and store in said memory the change of positions between said crane parts which are movable relative to one another, a servo valve, and a comparing unit inserted between said memory and said servo valve and arranged, upon reading of said memory during the operation of said crane to compare signals stored in said memory with signals which are continuously emitted by said encoders to open said servo valve to values corresponding to the difference between said continuously incoming signals and the signals emitted from said memory for the purpose of feeding a corresponding, required quantity of pressurized medium to the various hydraulic means, for the purpose of obtaining the pre-programmed movements of said crane parts, said electrical encoders being arranged to register the change of angular positions between any one of said crane parts and wherein a rotator is mounted at the outer end of said extension boom, said lifting means being supported by said rotator, said rotator having a motor driven gear rim provided thereon, a shaft supported on said rotator, a cog wheel mounted on said shaft, said gear rim cooperating with said cog wheel, said shaft being operatively connected to one of said encoders.

4. An improved hydraulic loading crane as claimed in claim 3 wherein said encoders are potentiometers.