According to regulations it is required to separate power supply circuits and control circuits in kitchen devices. For this reason, current kitchen appliances such as bar blenders have a user interface which provides galvanic separation of power control and speed adjustment. Thus, bar blenders typically have an on-off control switch, and a separate speed control input. There are various ways to implement the user interface to provide an easy to use device.
A first known approach is to provide a speed pre-selection switch and a separate push type on/off switch, which needs to be held on. The speed is pre-selected before the rotation of the tool is activated by pressing the on/off-switch. Some devices comprise an additional turbo switch to boost the speed.
A second known approach is to provide an on/off switch in the form of a switch which can be locked into its on and off positions, and a separate speed regulation switch. The speed regulation switch can be pressure sensitive or it can move along a pathway which is related to speed.
It would be more convenient to provide a combined on/off and speed regulation switch, to give a one-switch solution. This would enable user operation with only one user interface. However, this is inconsistent with the requirement for separate circuits. Furthermore, the amount of movement of the input switch for a hand held device such as a bar blender is limited since the whole device is gripped in the palm of the hand. A compact switch arrangement is therefore needed. In particular, a push switch should have a short path of movement, since long movement paths are associated by customers with low quality, and they also hamper accurate operation of the device.