Patent Number: 050139452
Section: summary

FIELD OF THE INVENTION The present invention refers to a linearly operating motor for stepwise advance of a driven member, such as a shaft, incorporating an elongated body with length variable properties and means for altering the length of the body. BACKGROUND OF THE INVENTION A motor of the above mentioned type is described in Swedish patent application No. 8700219-2. In this prior motor, the elongated body has magnetostrictive properties, whereby the motion required for advancing the driven member is brought about by axial displacement of the body. The purpose of the present invention is to provide a motor of the type mentioned in the introduction, wherein the elongated body is stationary and the motion required for effecting the advance of the driven member is obtained by means of the elongation of the body. SUMMARY OF THE INVENTION A motor according to the invention is inteded to be used e.g. where high precision is required for the motion generated, such as at traversing motors for precision adjustment and where the requirements for stroke length and power generation are rather small but also at applications, where longer stroke and larger power generation are required, such as in actuation of hoisting mechanisms. To this end the invention comprises an elongated body 10 with length variable properties, and means for changing the length of said body (10), said driven member 11 being provided with at least a first locking means 12, said first locking means 12, upon length increase of said body 10, being adapted to be brought into engagement with said driven member 11 by means of said length increase and said body 10 being adapted to act upon the first locking means 12 in such a manner that said locking means and thereby also said driven member 11 are displaced at length increase of the body 10.