Safety system for machinery
AssigneeALKEN Inc.
InventorsKeith Hanf, Allan Rodgers, Jr.
Life of this patent
Estimating the term…
Abstract
A safety system for a machine having a danger zone includes an induction coil having one or more turns extending along the periphery of a part of a worker's body as, for example, extending alone the fingers of a glove worn by the worker. A drive circuit applies a time-varying current having an identifiable characteristic such as the frequency of an alternating current. A magnetic field having the characteristic of the time-varying current is induced in an omnidirectional magnetic field sensor mounted adjacent the danger zone. The magnitude of this field is monitored. When the magnitude exceeds a threshold, a warning signal is issued and protective action may be taken, such as stopping or reversing the machine.
Claims12
A safety system for a machine having a danger zone comprising:
- (a) units including a sending unit having an inductor and a receiving unit having a magnetic field sensor with one or more transducers arranged to provide one or more transducer signals representing the strength of a magnetic field induced in the sensor, a first one of units being adapted for mounting to a body part, a second one of units being adapted for mounting adjacent to the machine adjacent the danger zone, at least one of the units being operative to send or receive magnetic fields omnidirectionally;
- (b) a drive circuit connected to the inductor, the drive circuit being operative to apply an time-varying current in the inductor having a drive characteristic such that the inductor emits a time-varying magnetic field having the drive characteristic;
- and
- (c) a detector circuit connected to the magnetic field sensor, the detector circuit being operative to provide a warning signal when the one or more transducer signals indicate that the magnitude of a magnetic field in the sensor varying with the drive characteristic exceeds a threshold value.
Dependencies are inferred from the claim text.