US4050010A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus utilizing a test surface with a magnetic flux gap for detecting dimensional disconformities of manufactured elements
Assignee: Caterpillar France SAS
•
Filing: 1976-02-24
•
Granted: 1977-09-20
•
Expires: 1996-02-24
Abstract
Abstract One or more dimensions of each of a series of similar manufactured elements, which are formed of magnetizable materials such as iron, steel, nickel or the like may be quickly checked for conformity to a predetermined value by momentarily positioning each successive element against an electromagnetic sensing device. The sensing device has a winding establishing a magnetic flux path through a core which is formed with one or more gaps in the magnetic circuit that are located to be spanned by a wrongly dimensioned or wrongly oriented one of the manufactured elements. Spanning of a flux gap of the core by a wrongly dimensioned or misoriented element changes the self-inductance value of the winding, and circuit means are provided for detecting such change in order to indicate the presence of a disconforming element or to actuate mechanism for rejecting or correcting the element.
Inventors
- 👤 Theophile Isnard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:56
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/001
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
247 words
Apparatus for determining if at least one dimension of each of a series of ferromagnetic elements differs from a predetermined desired value, comprising: an electromagnetic sensing device having a ferromagnetic core forming a magnetic flux path, said core having an exteriorly exposed test surface against which successive ones of said elements may be disposed in a predetermined position relative thereto, said core having a gap in said flux path at said test surface with said gap being located in said test surface to be spanned by disconforming ones of said elements which differ along said dimension from other conforming ones of said elements that conform to said desired value, said gap being further located in said test surface to remain unspanned by said conforming ones of said elements thereby causing said core to exhibit a substantially lower reluctance when a disconforming one of said elements is positioned against said test surface as compared with when a conforming one is positioned thereagainst, said sensing device further having an electrical winding magnetically coupled to said core to establish said magnetic flux therein, a power supply for electrically energizing said winding, circuit means for detecting a predetermind degree of change of the self-inductance value of said winding whereby said disconforming ones of said elements may be distinguished from said conforming ones thereof, and guide means for receiving each of said elements in sequence and for defining said predetermined position of said elements at said test surface of said sensing device.
Claim 2
Dependent Claim
247 words
Apparatus for determining if at least one dimension of each of a series of ferromagnetic elements differs from a predetermined desired value, comprising: an electromagnetic sensing device having a ferromagnetic core forming a magnetic flux path, said core having an exteriorly exposed test surface against which successive ones of said elements may be disposed in a predetermined position relative thereto, said core having a gap in said flux path at said test surface with said gap being located in said test surface to be spanned by disconforming ones of said elements which differ along said dimension from other conforming ones of said elements that conform to said desired value, said gap being further located in said test surface to remain unspanned by said conforming ones of said elements thereby causing said core to exhibit a substantially lower reluctance when a disconforming one of said elements is positioned against said test surface as compared with when a conforming one is positioned thereagainst, said sensing device further having an electrical winding magnetically coupled to said core to establish said magnetic flux therein, a power supply for electrically energizing said winding, circuit means for detecting a predetermind degree of change of the self-inductance value of said winding whereby said disconforming ones of said elements may be distinguished from said conforming ones thereof, and guide means for receiving each of said elements in sequence and for defining said predetermined position of said elements at said test surface of said sensing device.
Claim 3
Dependent Claim
169 words
The combination defined in claim 1 wherein said power supply is an alternating current source coupled to said winding of said sensing device, and wherein said circuit means for detecting said predetermined degree of change of the self-inductance value of said winding includes a bridge circuit having said winding as one arm thereof and having output terminals, said bridge being balanced to produce a minimum voltage difference between said output terminals thereof in the absence of ferromagnetic material spanning said gap of said core and to produce a higher output voltage between said output terminals when said gap is spanned by ferromagnetic material, and wherein said circuit means for detecting a predetermined degree of change of the self-inductance value of said winding further comprises a rectifier coupled to said output terminals of said bridge circuit, a set of relay contacts, a Schmitt trigger circuit having an input receiving said output of said rectifier, and means for operating said relay contacts in response to triggering of said Schmitt trigger circuit.
Claim 4
Dependent Claim
43 words
The combination defined in claim 2 further comprising time delay means connected between said rectifier and said means for operating said relay contact to prevent operation of said relay contacts unless said output from said rectifier continues for a predetermined interval of time.
Claim 5
Dependent Claim
42 words
The combination defined in claim 3 wherein said time delay means comprises a capacitor connected to the current path from said rectifier to said means for operating said relay contacts and a resistor connected to said capacitor for slowly discharging said capacitor.
Claim 6
Dependent Claim
92 words
The combination defined in claim 2 further comprising a voltmeter and switch means for selectively connecting said voltmeter to any selected one of a plurality of conductive points in said circuit means, said plurality of conductive points including at least a first point exhibiting a voltage indicative of said output voltage of said bridge circuit and a second point exhibiting a voltage indicative of the voltage at said input of said Schmitt trigger circuit, and means for adjusting voltage levels which occur at said conductive points during operation of said circuit means.
Claim 7
Dependent Claim
221 words
The combination defined in claim 1 wherein said power supply is an alternating current power supply and wherein circuit means for detecting a predetermined degree of change of the self-inductance value of said winding comprises a bridge circuit having a pair of input terminals across which said power supply is connected to provide alternating current voltage thereto and having a pair of output terminals and having said winding connected between one of said input terminals and one of said output terminals and having a first resistance connected between said one input terminal and the other of said output terminals and having a second resistance connected between said other input terminal and said other output terminal and having a third resistance connected between said one output terminal and said other input terminal, an amplifier having an input coupled to said other output terminal of said bridge, a rectifier receiving the output of said amplifier, a Schmitt trigger circuit having an input coupled to said rectifier to receive the output thereof, and having a reference voltage input and having an output which is energized in response to a predetermined voltage difference between said input and reference input, and means coupled to said output of said Schmitt trigger circuit for producing a faulty element signal in response to triggering of said Schmitt trigger circuit.
Claim 8
Dependent Claim
50 words
The combination defined in claim 6 wherein one of said resistances of said bridge circuit is a variable resistance, further comprising a variable capacitor connected in parallel with one of said resistances, and means for indicating the magnitude of the voltage difference between said output terminals of said bridge circuit.
Claim 9
Dependent Claim
93 words
The combination defined in claim 1 wherein said elements are cylindrical bushings having an axial bore which is of larger diameter at one end of said bushings than at the other end thereof, wherein said test surface of said core is circular and said gap thereof is annular and coaxially situated in said test surface, said annular gap having an inner diameter at least equal to that of the small diameter ends of said bushing bores and having an outer diameter not exceeding that of the large diameter ends of said bushing bores.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-19 | 1981-03-21 | 1981-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-19 | 1985-03-21 | 1985-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-19 | 1989-03-21 | 1989-09-20 | $7700.00 | Window Closed / Lapsed |