GB1303444A - - Google Patents

Abstract

1303444 Controlling jib cranes BALDWINLIMA-HAMILTON CORP 23 Jan 1970 [27 Jan 1969] 3396/70 Heading B8B A control device 35 for a jib crane 10 mounted on a vehicle 12 prevents the free end of the boom from passing a predetermined surface fixed with respect to a selected point remote from the vehicle. A vehicle orientation linkage assembly 36 has its first link 44 brought to a vertical position by an electric motor 68 operated in response to a mercury switch 72 mounted on the link 44. This positions a set of stops on a bank 38 mounted on a link 60 supported by links 46, 47 from the link 44. A jib elevation and length follower 42 causes corresponding movement of a switch bar assembly 40 with an arm 106 fixed to extend towards the path of the bank 38 of stop pins. The lowermost stop pin 83 acts as a reference point, one of the other pins 82<SP>1</SP> being selected to correspond to the selected surfacein this case a horizontal plane. The relative position of the bank 38 to the link 44 is normally fixed by a spring loaded friction brake acting between surfaces 134, 136 but this may be released by activating a solenoid 132 (the device 35 being inoperative). If this is carried out when the head 28 of the jib 16 is positioned at the selected reference point the reference stop pin 83 is brought to its required position, whereupon the solenoid 132 is deactivated and the control device 35 is set ready for use. The control device 35 may be modified to maintain the jib end 28 in a preselected vextical plane (not shown), or may be modified to maintain the jib end 28 in a predetermined curved or complex path by shaping the underside of bar 104, associated with the arm 106, appropriately, (not shown).