Patent US4633236A successfully refreshed from Google Patents.
US4633236A
Expired / Lapsed
US
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Mailbox
Assignee: BUL AUTOMATIC V/HOLGER BUHL
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Filing: 1985-06-21
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Granted: 1986-12-30
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Expires: 2005-06-21
Abstract
Abstract A mailbox including an indicator indicating the presence of mail, if any, and including a detector having a transmitting and receiving ultrasonic transducer. The transducer transmits ultrasonic waves into the mailbox and based on the received ultrasonic waves indicates alterations in the reflected energy. In this manner mail in the mailbox is detected even if the mail does not take up much room. The detector detects alterations in the frequency as a consequence of movements in the mailbox or detects alterations in the pattern of reflection as mail in the mailbox is disturbing the propagation paths of ultrasound in the mailbox.
Inventors
- 👤 Holger Buhl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:53
CPC Classifications
A; A47; A47G; A47G29/00; A47G29/12; A47G29/1209; A47G29/121; A47G29/1212
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
94 words
A mailbox comprising an indicator indicating the presence of mail, if any, said indicator including a transmitting and receiving transducer adapted to transmit ultrasonic waves within the mailbox and to receive reflections of ultrasonic waves from the mailbox in order to detect possible alterations in the reflected ultrasonic waves, said ultrasonic waves following one or more predetermined paths in the mailbox unless the ultrasonic waves are scattered or absorbed by means of mail in the mailbox, wherein one and the same ultrasonic transducer is used both for transmitting and receiving of said ultrasonic waves.
Claim 2
Dependent Claim
94 words
A mailbox comprising an indicator indicating the presence of mail, if any, said indicator including a transmitting and receiving transducer adapted to transmit ultrasonic waves within the mailbox and to receive reflections of ultrasonic waves from the mailbox in order to detect possible alterations in the reflected ultrasonic waves, said ultrasonic waves following one or more predetermined paths in the mailbox unless the ultrasonic waves are scattered or absorbed by means of mail in the mailbox, wherein one and the same ultrasonic transducer is used both for transmitting and receiving of said ultrasonic waves.
Claim 3
Dependent Claim
27 words
A mailbox as claimed in claim 1, characterized by the detector being adapted to detect alterations in the frequency as a consequence of movements in the mailbox.
Claim 4
Dependent Claim
19 words
A mailbox as claimed in claim 1, characterized by the ultrasonic waves having a frequency of about 80-100 kHz.
Claim 5
Dependent Claim
25 words
A mailbox as claimed in claim 1, characterized by means for recognizing the pattern of the reflected energy and indicating possible alterations in said pattern.
Claim 6
Dependent Claim
24 words
A mailbox as claimed in claim 1, characterized by the box on the inside being coated with a reflecting and an absorbing material, respectively.
Claim 7
Dependent Claim
21 words
A mailbox as claimed in claim 1, characterized by the path of the ultrasonic waves being terminated by a prismatic reflector.
Claim 8
Dependent Claim
19 words
A mailbox as claimed in claim 1, characterized by the ultrasonic waves having a frequency of about 40-100 kHz.
References Cited (Backward Citations)
US2038878A
Cited
US2197028A
Cited
US2968804A
Cited
US3309689A
Cited
US3634884A
Cited
US3909819A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |