GB1305894A - - Google Patents

Abstract

1305894 Vibration source locating G D FIRKINS 13 Feb 1970 [8 Jan 1969] 1188/69 Heading H4D An assembly for locating the source of vibrations in a structure (e.g. unwanted noises in a motor vehicle chassis or bodywork) comprises separately movable transducers for converting the vibrations into electrical signals and each having a mount for readily attaching it to and detaching it from a chosen position on the structure, and circuitry for transmitting signals, of a frequency characteristic of a particular vibration source, from a selected transducer to an output arrangement for comparing the amplitudes of the vibrations detected by the transducers. In the Fig. 2 embodiment transducers 1a<SP>1</SP>-1d<SP>1</SP> are attached by magnets or rubber suction pads to the structure and a selected pair is coupled via matching circuits 2a<SP>1</SP>, 2b<SP>1</SP>, tunable narrow bandpass filters 3a<SP>1</SP>, 3b<SP>1</SP> and amplifiers 4a<SP>1</SP>, 4b<SP>1</SP> to a pair of earphones 5a<SP>1</SP>, 5b<SP>1</SP>. Low-pass and high-pass filters 7a<SP>1</SP>, 7b<SP>1</SP>, 8a<SP>1</SP>, 8b<SP>1</SP>, whose tuning is ganged with filters 3a<SP>1</SP>, 3b<SP>1</SP>, shunt to earth frequencies above and below the pass band of filters 3a<SP>1</SP>, 3b<SP>1</SP>. The transducers are re-positioned to search out positions of maximum vibration amplitude. In alternative embodiments each transducer is provided with its own matching, filtering, amplifying and amplitude-indicating channel (Fig. 1, not shown) or all transducers are switched in turn to a single channel (Fig. 3, not shown).