Rotation compensation device for a cable or similar which can be wound on to and unwound from a rotary drum

A rotation compensation device for a cable which can be wound on to and unwound from a rotary drum which may make an indeterminate number of revolutions in one direction or in the other about a fixed shaft, comprising:

• two primary rotation compensation devices, wherein each primary rotation compensation device comprises
• a cable section of given length wound in a winding direction and forming several successive spirals, a first spiral, a last spiral and at least one intermediate spiral, the spirals, taken from one end to the other being preferred to as the rank of that spiral, each spiral surrounding the fixed shaft and disposed side by side, said winding directions for said spirals being all identical and the windings extending alternately from the center to the periphery of the chamber for a one spiral and from the periphery to the center of the chamber for the adjacent spiral, each spiral having a free end, the free end of said first spiral being fixed with respect to the fixed shaft and the free end of said last spiral being fast with the rotary drum and connected to said cable wound on said drum, and temporary coupling means being provided for coupling a given spiral in rotation with a spiral of immediately preceding rank when, during rotation of the rotary drum, said given spiral has effected a predetermined angular movement, the other end respectively, of said first and last spirals and corresponding ends of said intermediate spirals being fast with floating supports bringing together said corresponding ends of two adjacent spirals in the vicinity of the fixed shaft, and said temporary coupling mean being arranged so that coupling of said given spiral for rotation with the spiral of immediately lower rank takes place when said given spiral has effected a predetermined number, greater than or equal to two, revolutions,
• each primary rotation compensation device adapted for compensating a predetermined number of revolutions of the drum, said devices being mounted on the fixed shaft of the drum;
• a first junction means for connecting the fixed cable situated upstream of the drum to said free ends of the first two fixed spirals belonging respectively to said primary devices;
• a second junction means for connecting said cable wound on the drum to said free ends of the last two spirals driven by the drum and belonging respectively to said primary devices;
• two removable connecting members for connecting the so cables coming from said first junction means respectively to the two corresponding spirals;
• two drive means adapted for rotating said primary devices respectively;
• and
• control means adapted, when the drum is driven in rotation with a number of revolutions exceeding the compensation capacity of one of the primary devices for disconnecting said connecting member of this primary device at the same time as said connecting member of the other primary device is connected so as to insure continuity of the circuit, while the other primary device compensates the rotation of the drum, starting up the drive means of the primary device reaching the end of travel so as to bring it to its maximum compensation capacity considering the direction of rotation of the drum, reversing the operations when the their primary device in its turn reaches the end of tis compensation capacity, and continuing by causing alternate operation of one then of the other primary device while the one which is into operating is brought to its initial position.