US4461083A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Length or angle measuring instrument
Assignee: Dr Johannes Heidenhain GmbH
•
Filing: 1983-08-08
•
Granted: 1984-07-24
•
Expires: 2003-08-08
Abstract
Abstract In a measuring apparatus of the type having a measuring graduation which is scanned by a scanning unit that includes a scanning plate, the scanning plate is provided with at least two phase shifted scanning fields which are phase shifted with respect to one another in order to generate two analog scanning signals which are likewise phase shifted with respect to one another. In order to allow setting of the desired phase difference between the scanning signals, at least one of the scanning fields is made up of two partial scanning fields which are offset with respect to one another and are partially coverable by means of screws or diaphragms. The corresponding analog signal is made up of two partial analog signals obtained by use of the two partial scanning fields.
Inventors
- 👤 Alfons Ernst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:52
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/244; G01D5/247
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
193 words
In a length or angle measuring apparatus comprising a measuring scale and a scanning unit adapted to scan the scale; wherein the scanning unit comprises a scanning plate which comprises at least first and second scanning fields, phase shifted with respect to one another for generating respective first and second scanning signals which are phase shifted with respect to one another; and means for directing light at the scanning plate; the improvement comprising: first and second partial scanning fields included in said scanning field, said first and second partial scanning fields each oriented at a respective phase angle such that the first and second partial scanning fields are phase shifted with respect to one another; means for covering a selectable portion of at least one of the first and second partial scanning fields to an adjustable extent; and means for generating the first scanning signal as a function of light modulated by both the first and second scanning fields, such that the phase angle of the first scanning signal is adjustable in accordance with the extent to which the at least one of the partial scanning fields is covered by the covering means.
Claim 2
Dependent Claim
193 words
In a length or angle measuring apparatus comprising a measuring scale and a scanning unit adapted to scan the scale; wherein the scanning unit comprises a scanning plate which comprises at least first and second scanning fields, phase shifted with respect to one another for generating respective first and second scanning signals which are phase shifted with respect to one another; and means for directing light at the scanning plate; the improvement comprising: first and second partial scanning fields included in said scanning field, said first and second partial scanning fields each oriented at a respective phase angle such that the first and second partial scanning fields are phase shifted with respect to one another; means for covering a selectable portion of at least one of the first and second partial scanning fields to an adjustable extent; and means for generating the first scanning signal as a function of light modulated by both the first and second scanning fields, such that the phase angle of the first scanning signal is adjustable in accordance with the extent to which the at least one of the partial scanning fields is covered by the covering means.
Claim 3
Dependent Claim
30 words
The invention of claim 1 wherein the covering means comprises at least one screw mounted to the scanning plate to partially cover the at least one of the scanning fields.
Claim 4
Dependent Claim
30 words
The invention of claim 1 wherein the covering means comprises at least one diaphragm mounted to the scanning plate to partially cover the at least one of the scanning fields.
Claim 5
Dependent Claim
28 words
The invention of claim 1 wherein the generating means comprises a single photosensor positioned to respond to light modulated by both the first and second partial scanning fields.
References Cited (Backward Citations)
DE69936C
Cited
US3709611A
Cited
DE2518745A1
Cited
US4060903A
Cited
US4170828A
Cited
DE2724858A1
Cited
US4170829A
Cited
US4127772A
Cited
DE7814349U1
Cited
US4262423A
Cited
US4231662A
Cited
US4363964A
Cited
US4403859A
Cited
US4385836A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-24 | 1988-01-23 | 1988-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-24 | 1992-01-23 | 1992-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-24 | 1996-01-23 | 1996-07-24 | $7700.00 | Window Closed / Lapsed |