Weighing apparatus including a tapped electromagnetic load compensation coil
First Claim
1. In a weighing apparatus of the electromagnetic load compensation type including a frame (14);
- load support means (10,
12) connected for movement relative to the frame;
lever means (18) pivotally connected with said frame, a first portion of said lever means being connected with said load support means;
load compensation means including a compensation coil (28) connected with another portion of said lever means, and permanent magnet means connected with the frame adjacent said compensation coil;
position-responsive means operable upon the application of load to the load support for supplying compensation current to the compensation coil to maintain the load support means in its initial no-load position; and
indicating means for displaying the magnitude of the applied load as a function of the compensation current supplied to the compensation coil;
the improvement wherein(a) said coil includes intermediate its ends a tap for defining first and second coil portions (28a, 28b);
(b) and further wherein said compensation current supply means includes switch means (42) for supplying the compensating current alternately to said coil portions.
3 Assignments
0 Petitions
Accused Products
Abstract
Weighing apparatus of the electromagnetic load compensation type is disclosed, including a load support connected for movement relative to a frame, a mechanical-transmission ratio-establishing lever connecting the load support with a compensation coil arranged for displacement relative to a permanent magnet arrangement connected with the frame, a position-responsive circuit for supplying compensation current to the coil for creating an electromagnetic force that reacts with the permanent magnet field to maintain the load support in its initial no-load condition, and indicating means for displaying the magnitude of the applied load as a function of the compensation current. To permit the use of the lever in different lever-ratio-establishing environments without the use of attendant balancing weights, the compensation coil is tapped to define a pair of coil portions (28a, 28b) that are alternately energized by a switching device (42) to apply different forces upon the load support.
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Citations
9 Claims
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1. In a weighing apparatus of the electromagnetic load compensation type including a frame (14);
- load support means (10,
12) connected for movement relative to the frame;
lever means (18) pivotally connected with said frame, a first portion of said lever means being connected with said load support means;
load compensation means including a compensation coil (28) connected with another portion of said lever means, and permanent magnet means connected with the frame adjacent said compensation coil;
position-responsive means operable upon the application of load to the load support for supplying compensation current to the compensation coil to maintain the load support means in its initial no-load position; and
indicating means for displaying the magnitude of the applied load as a function of the compensation current supplied to the compensation coil;
the improvement wherein(a) said coil includes intermediate its ends a tap for defining first and second coil portions (28a, 28b); (b) and further wherein said compensation current supply means includes switch means (42) for supplying the compensating current alternately to said coil portions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- load support means (10,
Specification