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GB488442A - Improvements in or relating to alarm-devices, more particularly for air raid alarm - Google Patents

Improvements in or relating to alarm-devices, more particularly for air raid alarm

Info

Publication number
GB488442A
GB488442A GB5320/37A GB532037A GB488442A GB 488442 A GB488442 A GB 488442A GB 5320/37 A GB5320/37 A GB 5320/37A GB 532037 A GB532037 A GB 532037A GB 488442 A GB488442 A GB 488442A
Authority
GB
United Kingdom
Prior art keywords
alarm
mains
current
relating
devices
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB5320/37A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ERNST BUNZL
Original Assignee
ERNST BUNZL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ERNST BUNZL filed Critical ERNST BUNZL
Publication of GB488442A publication Critical patent/GB488442A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B27/00—Alarm systems in which the alarm condition is signalled from a central station to a plurality of substations

Landscapes

  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

488,442. Electric signalling systems. BUNZL, E. Feb. 22, 1937, No. 5320. Convention date, Feb. 22, 1936. [Class 40 (i)] Alarm bells or lamps connected to lighting mains are switched on by altering the strength or frequency of the current in the mains. A relay or the like connected to the mains responds to the mains variation and when operated connects the alarm device to the mains. The Specification as open to inspection under Sect. 91 comprises also the operation of the alarm by interrupting the current for a certain length of time or by superposing a current of different frequency on the mains and the switching in of emergency illumination with the alarm. This subject-matter does not appear in the Specification as accepted.
GB5320/37A 1936-02-22 1937-02-22 Improvements in or relating to alarm-devices, more particularly for air raid alarm Expired GB488442A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT488442X 1936-02-22

Publications (1)

Publication Number Publication Date
GB488442A true GB488442A (en) 1938-07-07

Family

ID=3675082

Family Applications (1)

Application Number Title Priority Date Filing Date
GB5320/37A Expired GB488442A (en) 1936-02-22 1937-02-22 Improvements in or relating to alarm-devices, more particularly for air raid alarm

Country Status (3)

Country Link
BE (1) BE420180A (en)
FR (1) FR818193A (en)
GB (1) GB488442A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2709801A (en) * 1952-03-31 1955-05-31 William S Sprague Blackout indicator

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2709801A (en) * 1952-03-31 1955-05-31 William S Sprague Blackout indicator

Also Published As

Publication number Publication date
BE420180A (en)
FR818193A (en) 1937-09-20

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