Dynamic scale utilizing shear measurements to determine a weight of bulk material
The invention relates to a dynamic scale for bulk material, having two swivel arms ( 2 ) and two load-lifting arms ( 8 ) mounted to the free end of said swivel arms, with one hole ( 7 ) being located in each of the swivel arms ( 2 ) and positioned transversely to the extension of the swivel arm and also transversely to the neutral fiber brought about by the flexural load. A pipe ( 9 ) is fitted into the hole ( 7 ) and is welded thereto. The pipe ( 9 ) comprises two sensors ( 14, 15 ) transversely to the longitudinal axis thereof, said sensors being located at an angle of substantially 90° to each other and each being disposed at an angle of ±45° to the direction of the shear stress component τ xy . Under the influence of the shear stress, the cross section of the tube ( 9 ) is deformed into an ellipse that is inclined at about 45°, the shorter and longer axis ( 11, 13 ) thereof being measured using the sensors ( 14, 15 ). Said sensors ( 14, 15 ) each comprise two force inlets ( 16, 17 ), which are inserted with pretension in suitable recesses in the tube ( 9 ).
1. A dynamic scale for bulk material comprising:
two swivel arms;
a sensor disposed with each swivel arm of the two swivel arms to measure a shear stress in each swivel arm of the two swivel arms, the sensor comprising:
a hole being oriented generally transverse to a neutral fiber of a bending strain of a swivel arm of the two swivel arms;
at least one sensing element disposed in the hole and oriented generally transverse to a longitudinal axis of the hole, the at least one sensing element being able to measure changes in a diameter of the hole resulting from shear stress; and
wherein the at least one sensing element is inserted and at angle of approximately ±45° to a direction of a shear stress τ xy of the swivel arm of the two swivel arms; and
an acceleration sensor disposed with at least one swivel arm of the two swivel arms to correct a determination of a mass by a current acceleration value.
2. The dynamic scale for bulk material according to claim 1 , wherein:
two sensing elements are disposed in the hole and are arranged at an angle of approximately 90° relative to each other;
a first sensing element of the two sensing elements measures enlargement of the diameter of the hole; and
a second sensing element of the two sensing elements measures contraction of the diameter of the hole.
3. The dynamic scale for bulk material according to claim 1 , wherein:
the at least one sensing element comprises two force inputs; and
each force input of the two force inputs is received, under pre-tension, into a recess in the hole.
4. The dynamic scale for bulk material according to claim 1 , wherein:
the at least one sensing element comprises two force inputs; and
each force input of the two force inputs is secured by a screw connection to a bracket that is secured within the hole.
5. The dynamic scale for bulk material according to claim 1 , wherein:
a weighing window is defined by measurements of the acceleration sensor; and
the measurements of the acceleration sensor do not exceed a given limit.
6. The dynamic scale for bulk material according to claim 1 , wherein a weighing window is defined by a traversal of the swivel arms past at least one contactless switch.
7. The dynamic scale for bulk material according to claim 5 , wherein a gross weight is measured during raising of the two swivel arms, and a tare weight is measured during lowering of the two swivel arms.
8. The dynamic scale for bulk material according to claim 5 , wherein determination of a load of a refuse container is made during traversal of the weighing window.
9. The dynamic scale for bulk material according to claim 1 , wherein the two swivel arms are constructed as at least one of a front-loading device, a side-loading device, and a rear-loading device.