Abstract: A tool (1) comprising a head (4) having at least two engaging surfaces (10) for driving the screwing member by its at least partially matching shape and a device (5) for driving the head rotation. The head globally behaves as a single-piece part when the screwing member is driven in rotation. The head includes a zone (7) linking the engaging surfaces and parts (9) transmitting to the engaging surfaces a rotation force applied on the driving device. The linking zone is located between the force-transmitting parts and the engaging parts. The head is designed such that the action of the rotational driving device on the force-transmitting parts tends to deform the shape of the head so as to bring the engaging surfaces closer to each other when a rotational driving force is applied via the driving device on the screwing member. The present invention is, for example, applicable to flat open-end wrenches.

Abstract: In this machine, an optical coding device furnishes a plurality of code numbers one of which is stored upon each rotation of the wheel to be balanced when the latter rotates at a stable measuring speed. This stored number corresponds to the passage of the imbalance through a predetermined position. Thereafter, the motor driving the wheel in rotation is switched off and the number is retained in the store and compared, in the course of a new rotation of the wheel, with the instantaneous number furnished by the coding device. The result of this comparison is displayed by three indicator lamps. When, in the course of the new rotation, the imbalance reaches the position it had at the moment of storage, one of the lamps lights up and the other two lamps are extinguished. The balancing weight must then be fixed to the wheel in a position diametrally opposed to the predetermined position.