integral with the wrapping member 16 and a hairpintype spring 30 one leg of which is retained against the barrel 14 by suitable means and the other leg of which is retained by the member 29 other biasing elements such as coil springs could also be utilized the wrapping member 16 also includes an actuating portion 17 having a leg 31 that extends beyond the pivot 28 toward the housing 11 the leg 31 includes a cam follower 18 that rests against the cam surface 34 of the cam 19 referring to fig2 and 3 when the cam follower 18 is positioned on one of the low points of the cam surface 32 as shown in the full line position in fig3 wrapping member 16 is positioned against the barrel 14 as shown in the full line position in fig2 when the drive unit 20 is energized as by push button switch 12 the drive shaft 21 is driven in turn causing rotation of the barrel 14 by reason of the biasing force provided by spring 30 the cam follower 18 remains in contact with the cam surface 34 and rotation of the barrel moves the follower along the surface in the direction of the arrows shown in fig3 as the follower moves along the cam surface it engages successive lobes 34 39 of the cam and causes the wrapping member 16 to pivot away from the barrel 14 thus when the follower 18 is positioned at the apex of the cam lobe as shown in the dotted line position in fig3 the wrapping member is pivoted to the dotted line position shown in fig2 however it should be realized that during this time the entire assembly comprising the barrel.