Method and apparatus for providing pre-travel balancing energy to an elevator drive

In an elevator system including an elevator car disposed for vertical translation in a shaft, an electric drive motor, a brake coupled to said motor, a counterweight disposed for translation in said shaft and cables coupling said car, said drive motor and said counterweight, the improvement comprising,

• means for measuring the total weight of said elevator car, passengers and cables suspended from said elevator car,
• means for storing said measured weight at a lower and an upper operating limit of said elevator car,
• means for determining and storing an energy input to said drive motor to maintain said elevator car stationary at said upper and lower operating limits of said car,
• means for normalizing said total measured weight to represent the weight of said passengers in said elevator car, and
• means for determining an energy input level to said electric drive motor which maintains said elevator car substantially stationary upon release of said brake.

A method of providing pre-travel balancing energy to an electric elevator drive motor comprising the steps of,

• measuring and storing the total weight of an elevator car and suspended cables and the lowest and highest floor levels in an installation,
• measuring and storing the energy necessary to maintain said elevator car and suspended cables stationary at said lowest and highest floor levels in an installation,
• utilizing said stored weight data to provide an interpolation signal representing the weight of said suspended cables,
• providing a data signal representative of the weight of passengers in said elevator car,
• generating a drive signal controlling said drive motor which maintains said elevator car substantially stationary.

A load cell assembly for measuring the total weight of an elevator car including passengers and suspended cables comprising, in combination,

• an elevator car supported in a frame,
• a first plate,
• means for coupling said first plate to said frame,
• a plurality of cables,
• a second plate disposed below said first plate,
• means for coupling said plurality of cables to said second plate, and
• a plurality of load cells disposed between said first plate and said second plate.

A load cell assembly for measuring the total weight of an elevator car including passengers and suspended cables comprising, in combination,

• an elevator car supported in a frame,
• a first plate,
• means for coupling said first plate to said frame,
• a plurality of cables,
• a second plate disposed below said first plate,
• means for coupling said plurality of cables to said second plate, and
• three load cells disposed between said first plate and said second plate and arranged in a triangle about the line of action of said plurality of cables.

A load cell assembly for measuring the total weight of an elevator car including passengers and suspended cables comprising, in combination,

• an elevator car supported in a frame, said frame having a first load bearing surface,
• a plurality of cables,
• means disposed below said first load bearing surface having a second, opposed load bearing surface,
• means for coupling each of said plurality of cables to said just recited means, and
• three load cells disposed between said first and said second load bearing surfaces and arranged in a triangle about the line of action of said plurality of cables.