Patent ID: 9393701
Filing Date: 2016-07-19
CPC Classification: B23Q,B25J,F03G,H01F

Claim Text:
1. A device for gripping and withholding workpieces made of ferromagnetic material by means of at least one permanent magnet, the device comprising: a supporting casing ( a magnet-holder member ( actuator means (E, A the magnet-holder member ( 4 ) bears the permanent magnet (M) at a front end and moreover bears at a distal end an auxiliary magnet (m), which generates a magnetic field of lower intensity than that of the main magnet (M), the auxiliary magnet (m) adhering to a metal wall ( 2 c ) of the casing ( 2 ) when the magnet-holder member ( 4 ) is in its retracted position so as to keep the magnet-holder member ( 4 ) stably in the retracted position even after an interruption of the passage of electric current through the first shape-memory actuator elements (A 1 , A 2 ), which are used for displacing the magnet-holder member ( 4 ) towards the retracted position, wherein the first actuator elements (A 1 , A 2 ) are selectively adapted to positionally displace the magnet-holder member ( 4 ) toward the wall ( 2 c ) along an axis ( 3 a ) equal to the entire length necessary to pass from the operative position of the main magnet (M) to the position in which the auxiliary magnet (m) is in contact with the wall ( 2 c ) of the casing ( 2 ), whilst the second actuator elements (B) are selectively adapted to positionally displace the magnet-holder member ( 4 ) toward the advanced position along the axis ( 3 e ) equal just to a portion of the aforesaid length, the remaining portion of displacement forwards being obtained via the magnetic attraction between the main magnet (M) and the workpiece (L) to be clamped, wherein slidably mounted within the casing (