| 摘要 |
<p>An electro-magnetically operated device, for example for use as a valve to control fluid flow, in which a magnetisable armature 10, extends into an air gap between opposite permanent poles of a magnetic circuit 24, 26, and is movable, between two end positions adjacent the poles through an intermediate position towards which it is resiliently biased. The armature motion may be sliding in a guide, or pivoting. An electromagnet 32, 30, when energised, polarises the armature so that it is attracted to one or other of the permanent poles. Adjusting the air gaps between the armature and each pole to balance the resilience of the armature will produce a bistable characteristic in which the armature will always lie adjacent one or other of the poles, and can be switched to the opposite pole by reversing the energising current. Alternatively, a monostable characteristic is enabled by unequal air gaps. An embodiment is described where a wedge shaped armature rocks in a V-shaped gap between two poles (fig 11), and in a further embodiment, two V-shaped air gaps containing two armatures are back to back (fig 14). A separate invention is described, whereby a resilient magnetisable armature is sandwiched between two parts of a magnetic circuit, the resilient force generated by deflecting the resilient material from an undeflected condition to one side or the other.</p> |
