EP 0649075 B1 19970102 - Spring barrel delivering a constant torque
Title (en)
Spring barrel delivering a constant torque
Title (de)
Ein, ein konstantes Drehmoment lieferdendes, Federgehäuse
Title (fr)
Barillet à ressort délivrant un couple constant
Publication
Application
Priority
CH 308693 A 19931013
Abstract (en)
[origin: EP0649075A1] The drive spring (3) is coiled inside a barrel through an angle alpha = n2 pi radians. The spring has a rectangular cross-section of constant width. At least a first portion of the spring extending from the wall (2) of the barrel towards the arbor (5) has an increasing thickness e chosen in such a way that the angle of coiling alpha times the value cubed of the thickness e has a constant value, ie alpha .e<3> = constant. There is thus obtained, at least during the useful part, ie conventionally during the first 24 hours of running, a constant force delivered by the barrel and consequently a constant amplitude of the balance. <IMAGE>
IPC 1-7
IPC 8 full level
CPC (source: EP US)
G04B 1/14 (2013.01 - EP US)
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 0649075 A1 19950419; EP 0649075 B1 19970102; CH 685582 B5 19960229; CH 685582G A3 19950831; DE 69401328 D1 19970213; JP H07209438 A 19950811; US 5539708 A 19960723
DOCDB simple family (application)
EP 94115925 A 19941010; CH 308693 A 19931013; DE 69401328 T 19941010; JP 27310694 A 19941013; US 31291394 A 19940929