Crane control means employing load sensing devices

In a crane:

• a support;
• a boom mounted on said support;
• first drive means operable to effect swinging movement of said boom;
• second drive means operable to effect luffing movement of said boom;
• and control means for said crane comprising:
• load sensing means mounted on said boom for sencing loads imposed on said boom, including any down load and any side load, and for providing electrical signals indicative of the magnitude and direction of said loads;
• transducer means for sensing the luffing angle of said boom and for providing an electrical signal indicative of said luffing angle;
• and computer means for receiving said electrical signals from said load sensing means and the electrical signal from said transducer means and for providing output signals representing the magnitude and direction of any load moment on said boom, including the magnitude and direction of any side load moment acting on said boom, and further including the magnitude of a downwardly acting load moment on said boom, said output signals effecting operation of either or both of said drive means to move said boom to maintain any load moment below a predetermined magnitude.

In a tower crane:

• a tower;
• a boom mounted on said tower for vertical pivotal movement;
• first drive means operable to effect rotation of said tower to effect swinging movement of said boom;
• second drive means operable to effect vertical pivotal luffing movement of said boom relative to said tower;
• and control means for said crane comprising:
• boom load sensing means mounted on said boom for sensing the magnitude and direction of a load imposed at a predetermined location on said boom and for providing electrical signals indicative of said magnitude and direction of said load;
• transducer means for sensing the luffing angle of said boom and for providing an electrical signal indicative of said luffing angle;
• torque load sensing means mounted on said tower for sensing the magnitude and direction of a load imposed at a predetermined location on said tower and for providing electrical signals indicative of the magnitude and direction of the torque load imposed on said tower;
• and computer means for receiving the electrical signals from said boom load sensing means, for said torque load sensing means, and from said transducer means and for providing output signals representing the magnitude and direction of any load moment imposed on said boom, including a down load moment and a side load moment, at said predetermined location on said boom, and representing the magnitude and direction of any torque load moment imposed on said tower, said output signals being usable to operate either or both of said drive means to move said boom to maintain the imposed load moments below a predetermined magnitude.

In a crane:

• a support;
• a boom mounted on said support and having opposite lateral sides, said boom comprising at least two separable boom sections arranged end-to-end,
• drive means operable to effect lateral swinging movement and luffing movement of said boom;
• and control means for sensing any side load and any down load imposed on said boom, for determining the magnitude and direction of the load moment, and for providing an electrical output signal to effect operation of said drive means to move said boom to maintain said load moment below a predetermined magnitude,
• said control means comprising load sensing means mounted on opposite lateral sides of said boom and between said boom sections for sensing compression and tension forces occurring in said opposite lateral sides of said boom when a load is imposed on said boom, and for providing electric signals representing magnitude and direction of said load,
• said control means further comprising computer means for receiving and processing said electric signals from said load sensing means to ascertain the load moment and for providing said electrical output signal to operate said drive means,
• said computer means operating to compare said electric signals from said load sensing means to ascertain differences in the magnitude and direction thereof in order to provide an output signal indicative of any side load moment,
• said computer means further operating to add said electric signals to provide an output signal indicative of a total downward load moment on said boom.