Geometrical instruments – Area integrators – Electrical
Patent
1986-12-18
1988-10-18
Haroian, Harry N.
Geometrical instruments
Area integrators
Electrical
33172E, 271263, G01B 2108
Patent
active
047777290
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an apparatus for the contacting measurement of differences in thickness of sheet material which is supplied to the apparatus with the aid of a transport system, comprising a measuring gap provided on the plane of transport and formed by an abutment disposed rigidly with respect to the measuring gap, and a first sensing element capable of being deflected respect to the measuring gap perpendicular to the sheet material.
German Pat. No. 31 33 818 discloses a thickness measuring apparatus for mechanically measuring the thickness of chip boards. Differences in the thickness of the material under test are measured in a measuring gap between a sensor in the form of a sensing roller and a rigid plate support.
In this apparatus the sensing roller is connected with a rod which is disposed in a first cylinder-piston assembly (measurement cylinder) so as to be movable up and down. The geometry of the measuring cylinder is such that the piston can absorb the measuring displacement by means of an air cushion. A second cylinder-piston assembly (adjustment cylinder) is coupled with the first in mechanically rigid fashion and has the function of performing the null balance of the apparatus, or adjusting the measuring system to the thickness "d" to be expected for the material under test.
During the thickness measurement the pressure is very high in the adjustment cylinder compared with that in the measurement cylinder so that the differences in thickness arising due to the material under test can be picked up by the measurement cylinder in the tolerance range d.+-..DELTA.d without being affected by movements of the adjustment cylinder. If overthicknesses occur in the measuring gap which exceed the tolerances of .+-..DELTA.d, the permissible working range is exceeded in the measurement cylinder and the forces caused by the overthickness are transfered to the cylinder-piston assembly, which is now acting as a rigid abutment. Since no measures are provided for protecting the thickness measuring apparatus from overthicknesses, this necessarily leads to the measuring system being damaged or maladjusted.
It is basically conceivable to use a thickness measuring apparatus which functions according to the above-described principle for automatic bank note sorters as well.
When used for this purpose, however, the contacting thickness measurement is problematic since the necessary measuring speeds are much higher and the material under test is transported in a much faster sequence through the measuring apparatus and the differences in thickness to be measured are much smaller. Sheets which are folded or lie on top of each other or even foreign bodies such as paper clips or the like can in practice not be prevented from passing through the thickness measuring apparatus. These abnormal cases sometimes have a thickness many times greater than the "standard thickness." They easily lead to jamming in the transport system and to the measuring system being damaged or maladjusted. Since such disturbances usually have to be eliminated manually, the throughput of the voucher sorter may be very greatly reduced.
The invention is therefore based on the problem of proposing an apparatus for the contacting measurement of differences in thickness of sheet material, which avoids the above-mentioned disadvantages.
This problem is solved according to the invention by the features stated in the characterizing part of the main claim.
The basic idea of the invention is to provide in front of the actual measuring gap a pretest sensing element which preferably forms together with the abutment of the first sensing element a pretest measuring gap, the pretest sensing element responding to overthicknesses in the arriving material under test and, if necessary, swiveling the measuring system out of the plane of transport. The pretest sensing element, which detects the overthickness and is itself insensitive to mechanical action, picks up the forces arising due to overthicknesses and uses them to swivel away the measuring system, t
REFERENCES:
patent: 2503720 (1950-04-01), Gieseke
patent: 2841876 (1958-07-01), Pittenger
patent: 3354273 (1967-11-01), Bleiman
patent: 4068385 (1978-01-01), Mitzel
patent: 4073488 (1978-02-01), Uchida
GAO Gesellschaft fur Automation und Organisation mbH
Haroian Harry N.
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