The present invention relates to a two-drum hoisting-winch including a reduction gear, of the type used on cranes adapted to be quickly erected. One of the drums is used for winding the lifting cable for the loads, while the other drum is used for winding the cable serving to erect the crane. In other words, one of the drums is used when the other one comes to a standstill, and vice versa.
A hoisting winch according to the invention includes a motor actuating two winch drums, and is characterized in that the two drums are connected to the driving shaft of the motor through a differential reduction gear, while means are provided for bringing to a standstill either of the two drums, as required.
According to another feature of the invention the differential reduction gear is constituted by a train of epicycloidal pinions, the sun pinion of which is rigid with the driving shaft, while the shaft of the planet pinion carrier is connected to one of the drums, the cage of the crown wheel of the epicycloidal train being, besides, connected to the other drum.
The locking means for the drums may be constituted by retractable bolts. As regards the drum, that used for lifting the loads, the locking bolts may be omitted, it being understood that the locking is effected by the cable wound on said drum, said cable being held fast, for instance, by the lifting hook of the crane brought into abutment.
According to a further feature of the invention, a torsion shaft connects the planet pinion carrier of the reduction gear to the drum used for the erection of the crane.
The attached drawing, given by way of non-limiting example, will allow the features of the invention to be better understood.
FIG. 1 is an axial section of a winch according to the invention for a first possible position of use;
FIG. 2 is a partial section view, showing the engagement means for the second position.
The winch illustrated in the drawing comprises:
A. A PLANETARY REDUCTION GEAR 1, THE CAGE 2 OF WHICH IS INTEGRAL WITH THE LIFTING DRUM 3;
B. A CRANE SETTING UP DRUM 4, ROTATIVELY DRIVEN BY A TORSION SHAFT 5 ROTATIVELY CONNECTED TO THE PLANET-WHEEL CARRIER 17 OF THE LAST TRAIN OF THE REDUCTION GEAR, ON THE ONE HAND, AND TO THE SETTING UP DRUM 4, ON THE OTHER HAND:
C. A DRIVING BRAKE-MOTOR 6 (EITHER ELECTRIC OR HYDRAULIC), THE SHAFT OF WHICH IS CONNECTED TO THE SUN-WHEEL 18 OF THE FIRST GEAR TRAIN;
D. THREE SUPPORTS 7, 8, 9, INTERCONNECTED BY THREE OR FOUR CONNECTING RODS 10; THE SUPPORTS 7 AND 8 SUPPORT THE LIFTING DRUM 3 THROUGH THE ROLLER BEARINGS 11 AND 12, WHILE THE SUPPORTS 8 AND 9 SUPPORT THE SETTING UP DRUM 4 THROUGH THE ROLLER BEARINGS 13 AND 14; THE SUPPORT 7 IS ALSO USED FOR CARRYING THE MOTOR 6;
E. TWO BOLTS, 15 AND 16.
The bolt 15 allows holding the lifting drum fast to the support 7.
The bolt 16 allows holding the setting up drum 4 to the support 9 fast.
The planetary reduction gear 1 comprises two crown gears 20 and 21 integral with the interior of the cage 2; the sun wheel 18, driven by the shaft of the motor 6, engages a first planetary-reduction wheel or gear 22 between the sun wheel 18 and the crown gear 21. The first planetary reduction gear 22 in turn, through suitable connection drives a second sun wheel 19 which engages a second planetary reduction wheel 23 carried by the carrier 17 and lying between the crown gear 20 and the second sun wheel 19.
The operation is as follows:
When the lifting drum 3 is to be used, the bolt 16 is brought to the position illustrated in FIG. 2, that is, the bolt 16 locks the setting up drum 4. The torsion shaft 5 connected to the drum 4 is thus unable to rotate, whereby the planet-wheel carrier 17 connected to the shaft 5 is held fast.
The driving motor 6 is started, and rotates the sun-wheel 18 and, after reduction, the sun-wheel 19; since the planet-wheel carrier 17 is locked, the crown wheel 20 will rotate, so that said crown wheel, which is integral with the cage 2 of the reduction gear 1 connected to the lifting drum 3, will rotate the latter.
On the other hand, if the setting up drum 4 is to be used, the bolt 15 is brought to the position shown in FIG. 1 to hold the lifting drum 3 fast, while the bolt 16 is released to free the setting up drum 4.
The crown wheels 20 and 21 are held fast through the agency of the reduction gear cage and the lifting drum.
The rotation of the motor shaft causes, after reduction, the torsion shaft 5 to rotate due to the planetary movement of the second planetary reduction wheel 23 connected to its carrier 17, whereby the setting up drum 4 is rotatively driven.
In a modified embodiment, not shown, any driving means whatever may be provided (hydraulic motor, thermic or electric motor), such means being mounted parallel to the axis of the winch, so that the motion is transmitted by belts, a pulley fitted with the safety brake being mounted on the shaft driving the reduction gear.
According to a further modified embodiment, not shown, it is possible to hold the lifting drum 3 fast by means of the lifting cable of the crane, the lifting hook being then in abutment in its uppermost position against the truck of the crane jib. This arrangement makes it possible to omit the bolt 15.