shaver having automatic switch-off function
Publication Date: 2013-Nov-26
The IP.com Prior Art Database
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Title: shaver having automatic switch-off function
Herewith we describe an electric grooming device having a main body accommodating an electric motor. The grooming device has two or more different hair-cutting attachments that can be interchangeably coupled to the main body to be driven by the motor, for example a shaving attachment, a hair-trimming attachment or a hair-clipping attachment. When no attachment is coupled to the main body, a level of the sound produced by the grooming device when the motor is running is relatively low, so that in this situation a user may not notice that the motor is still running after decoupling of an attachment from the main body. We propose a switch-off function for the motor which automatically switches off the motor when no attachment is coupled to the main body. The switch-off function may also automatically switch off the motor when no hairs are cut anymore.
The proposed automatic switch-off function is based on a measurement of the actual electric current flowing through the motor or the actual power consumption of the motor. This measurement can for example be performed by means of an elementary sense-resistor using the ADC capability of the shaver processor or an external ADC in the shaver. The measured actual current or power consumption shows different characteristics for the situation without an attachment, the situation with an attachment but without a hair-cutting action, and the situation with an attachment and with a hair-cutting action (see figure 1). In particular the power fluctuations for a grooming device with an attachment with no hair-cutting action are between about 6-8%, and the power fluctuations for a grooming device with an attachment w...