Abstract A file protect system for a magnetic recording unit includes a diaphragm actuated switch for sensing the presence of the reel ring. A supply port in a conical shaped projection guides air under pressure toward the position occupied by the reel ring. When the ring is not present, the uninterrupted flow of air creates a slight vacuum in a return port. The return port extends through the conical projection and is within and on the same center line as the supply port. Flexible tubing connects the return port to the diaphragm actuated switch. When a reel ring is present in the reel, the flow of air from the supply port is disrupted thereby creating a slight pressure increase in the return port. This pressure operates the diaphragm actuated switch thereby producing a NOT FILE PROTECT or WRITE ENABLE signal which allows the magnetic tape unit to write on the tape.
Inventors
👤 D Olmsted
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-25 16:56
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/02; G11B15/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
144 words
A file protect system for a magnetic recording and reproducing unit of the type in which magnetic heads alter the magnetic state of the magnetic tape only if a reel ring is inserted in the reel of magnetic tape comprising: an air supply port disposed adjacent to the position of said reel ring, a return port adjacent to said supply port, means for supplying air flowing freely from said supply port to create a vacuum within said return port due to venturi effect, said means causing a pressure increase in said return port when the flow of air for said supply port is disrupted, and a diaphragm actuated electrical switch, said return port being connected to operate said switch to produce a write enable signal with the presence of a reel ring in said reel disrupting the flow of air from said supply port.
Claim 2
Dependent Claim
144 words
A file protect system for a magnetic recording and reproducing unit of the type in which magnetic heads alter the magnetic state of the magnetic tape only if a reel ring is inserted in the reel of magnetic tape comprising: an air supply port disposed adjacent to the position of said reel ring, a return port adjacent to said supply port, means for supplying air flowing freely from said supply port to create a vacuum within said return port due to venturi effect, said means causing a pressure increase in said return port when the flow of air for said supply port is disrupted, and a diaphragm actuated electrical switch, said return port being connected to operate said switch to produce a write enable signal with the presence of a reel ring in said reel disrupting the flow of air from said supply port.
Claim 3
Dependent Claim
18 words
The file protect system recited in claim 1 wherein said supply port is in a conical shaped projection.
Claim 4
Dependent Claim
25 words
The file protect system recited in claim 2 wherein said return port is within said conical shaped projection and is concentric to said supply port.
Claim 5
Dependent Claim
19 words
The file protect system recited in claim 3 wherein said return port is recessed in said conical shaped projection.
Claim 6
Dependent Claim
28 words
The file protect system recited in claim 1 wherein said return port passes through the conical projection and is on the same center line with said supply port.