Claims:
1. In a reeling device for at least one load rope or cable and at least one safety rope or cable both being attached to a cage for suspending the cage to be lifted and lowered and used, for example, in front of buildings, the device including, a single reeling drum having a spiral groove;
2. In a device as in claim 1, the means for compensating establishing a temporary storage facility for a portion of the one of said cables or ropes wound on the drum at larger diameter, and into which facility said portion is fed gradually upon unwinding the one cable or rope having large diameter on the drum than the concurrently unwound other one of the cables
3. In a device as in claim 1, the means for compensating including a spring-biased auxiliary drum effective between the cage and the safety cable or rope, and reeling the difference in lengths as of the safety cables or ropes, the means for compensating further including locking means connected to the load cable or rope for locking the auxiliary drum
4. In a device as in claim 2, the storage facility, including at least one pulley mounted at a variable distance from the drum and engaging one of said cables or ropes for extending the effective length thereof between
5. In a device as in claim 2, the storage facility, including a pivotable arm having a pivot, a pulley on the arm opposite the pivot thereof for engaging one of said cables or ropes for establishing a compensating lengthening for the one cable or rope through pivot motion whereupon the pulley moves on an arc.
Description:
BACKGROUND OF THE INVENTION
The present invention relates to devices for reeling of ropes or cables suspending outdoor elevator cages or the like, to be lifted up and down along the front of buildings; the ropes or cables are to be wound onto and unwound from a drum.
Cages that are lifted and lowered in front of buildings are usually equipped with safety cables in order to prevent uncontrolled dropping in the case the load bearing cable or rope breaks. It is particularly required that the safety cable catches the cage immediately, i.e., as soon as the cage is no longer held by the main, load bearing cable. The safety cable is reeled separately or on a separate portion of the main reeling drum onto which the load cable or rope is wound upon lifting the cage. In either case, the safety rope or cable occupies additional space, and the reeling and winching equipment for the safety rope or cable adds to equipment cost and weight.
DESCRIPTION OF THE INVENTION
It is an object of the present invention to provide reeling equipment for load and safety ropes or cables, having winch mechanism which includes but one drum and is constructed for minimizing weight as well as the requirements for space. In accordance with the preferred embodiment of the invention, safety and load ropes or cables are wound one on top of each other, i.e., in two layers on a drum; compensating means are provided for continuously compensating differences in reeling length, which occur due to the differences in reeling diameter on the drum for the two different ropes or cables. The compensating means include a temporary cable or rope storage facility into which the drum feeds that one of the cables or ropes which is wound onto the drum at a larger loop diameter (because the other cable or rope is underneath), so that the lengths of the two cables as effective on the cage for lowering and for lifting, remain similarly. This way, the cage will not drop when load carrying is shifted from the principle cable or rope to the safety cable or rope.
A continuously spring-biased auxiliary reeling drum is provided between cage and safety rope or cable in accordance with one mode of practicing the invention. The auxiliary drum can be locked by means of a pawl or pawls operated by the load cable or rope, and kept disengaged from locking position as long as the load cable or rope is operative. Upon breakage, the pawl or pawls lock the auxiliary drum.
In an alternative example, one or more pulleys are provided at variable distance from the main drum. The distance between such a pulley or pulleys and the drum varies during turning of the drum corresponding to the difference in length between load and safety ropes and cables as wound onto or unwound from the common drum, due to different diameters of the respective loops on the drum. In a still further example, one or more outrigger or boom-like arms are pivotably mounted and carry pulley or pulleys in axis parallel relation to the drum on the displaceable end of the arm. The pulley's axis undergoes pivotal displacement accordingly and thereby compensates the difference in reeling diameter and actually effective length of the cable having larger loop diameter when wound, so that the unwound lengths of load and safety cables/ropes as effective on the cage, are the same for lowering or raising the cage as required.
In all these cases, load and safety ropes or cables are wound on a single drum, one on top of the other so that the equipment as a whole does not occupy much space. Actually, little space is required in addition to the space occupied by the principle equipment for reeling and winding the load rope or cable by itself. The drum for reeling the two ropes or cables does not have to be longer than needed for winding one cable or rope on the drum and in a single layer. As length differences in the ropes or cables are duly compensated, the winch mechanism has very small dimensions and low weight.
The principle of the invention as far as mechanization is concerned, has broader applications. For example, a control cable may be reeled in that manner in lieu of a safety cable. However, the invention can actually be practiced in reeling three layers of ropes and/or cables on a single drum. Of course, in this case, a second, analogously operating length compensating device has to be used.
In case the load rope or cable breaks, the safety rope or cable will immediately take up the load, so that the cage will not drop. Persons in the cage will not be injured by any impact shock that would occur if a sudden drop of the cage were followed by a likewise sudden stopping of the cage when the safety rope catches. In the present circumstances, load and safety cables or ropes have their effective unreeled length available in such a manner that the load can shift from one to the other without sudden change in effective cable length through cage dropping.
In accordance with a refinement of the invention as practiced, the load can be distributed among the two cables or ropes as wound in layers onto the single drum. Each cable or rope is proportioned to take the full load; by distributing the load normally upon the two cables or ropes, overall safety is increased and probability of breaking is reduced. This arrangement can be interpreted in that each cable or rope is the safety element in case of breaking of the respective other one. A still further safety rope or cable is not needed.
While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which:
FIG. 1 is a somewhat schematic view of the rope or cable arrangement as reeled, but without length compensation included in the illustration;
FIG. 2 is a cross section through a portion of the main drum when holding load and safety cables or ropes in different layers;
FIG. 3 is similar to FIG. 1, except that the Figure is supplemented by an auxiliary drum as a first example for length compensation of one of the cables or ropes as reeled;
FIG. 4 shows the auxiliary drum of FIG. 3, but with supplemental equipment and in somewhat greater detail in parts;
FIG. 5 is a side elevation of another example for length compensation; and
FIG. 6 is a side elevation of still another example for length compensation.
DESCRIPTION OF THE DRAWINGS
Proceeding now to the detailed description of the drawings, FIG. 1 illustrates a reeling drum 1 for a pair of load cables or ropes 3 carrying an outdoor elevator type cage 2 to be lowered and lifted in front of buildings or the like. Drum 1 is driven by a winch motor 20. Cable/rope 3 may be a single piece that passes through cage 2 and is affixed thereto, but two cables or ropes can be used which are then individually fastened to the cage. Load cable/rope 3 is wound onto drum 1 in a first layer. A pair of safety ropes or cables 4 are wound onto the drum 1 and in a second layer thereon (see FIG. 2). The drum is provided with grooves 5 (i.e., with two helical grooves) for properly positioning the individual loops of cables/ropes 3. The providing of such positioning grooves is not essential in principle but advantageous in practice. For purposes of describing the invention, just one suspension pair of a load cable/rope 3 and one safety cable/rope 4 needs to be considered.
It can be seen that the safety cables/ropes 4 each are wound in the grooves as established between adjacent loops of the load cables/ropes as wound onto the drum. As can be seen in FIG. 1, the load cable/rope 3 appears to the left of safety cable/rope 4, but one more loop of a cable or rope 3 is wound onto the drum. This first loop 3a appears to the right on the drawing of FIG. 1. Thus, as the first loop 4a of cable/rope 4 is being wound, a second loop 3b of cable/rope 3 is being wound concurrently, so that the former becomes situated in the groove of the first and second loop of cable/rope 3. Since cable/rope 3 is received in the grooves 5, cable/rope 4 cannot be squeezed in-between loops 3a, 3b. Thus, each safety cable/rope 4 is somewhat laterally (axially) displaced from the load cable/rope 3, as it runs towards drum 1, and as the winding and reeling progresses, each loop of the former is wound on and in-between the concurrently established loop of the latter and of the preceding one. This way, cable/rope 3 is wound directly onto drum 1 and cable/rope 4 is wound thereon as a second layer. As each loop of cable/rope 4 has a larger diameter than each loop of cable/rope 3, it is necessary to obtain length compensation, because for each revolution different lengths are reeled for the two cables or ropes.
An auxiliary drum 6 is provided, e.g., inside cage 2, and actually provides the point of fastening cable 4 to the cage. Drum 6 is provided with a gear 7, and a pawl 8 is pivoted on the drum for selective engagement with the teeth of wheel 7 so as to lock drum 6. The other arm of pawl 6 is affixed to rope or cable 3.
The drum 6, as journalled in cage 2, is springbiased (not shown -- conventional), so that the drum has the tendency to rotate in direction of arrow A. The end of cable/rope 4 is affixed to the drum, and the spring bias tends to wind the cable/rope 4 onto drum 6. As the main drum 1 turns, more of the cable/rope 4 is reeled than of the cable/rope 3, due to the different loop diameters on drum 1. The length difference is taken up by auxiliary drum 6.
In case cable/rope 3 breaks, pawl 8 engages a detent in wheel 7 and, thus, locks the auxiliary drum 6, so that the sudden shift of load to cable/rope 4 does not unwind drum 6. A spring 9 may aid in the rapidity of pawl action for locking the auxiliary drum as fast as possible.
A similar auxiliary drum may be provided for the other, symmetrical disposed safety cable/rope 4, but the same auxiliary drum could be used for both of them.
Proceeding now to the description of FIG. 5, load cable/rope 3 and safety cable/rope 4, are wound onto drum 1, also here in two layers. A boom arm 10 is provided with a pulley 11 near the top, and cage 2 is suspended by cable/rope 3 as running from drum 1 over pulley 11. Safety cable/rope 4 is likewise wound on drum 1 and runs over pulley 11. However, the cable/rope 4 runs additionally over a pulley 12, journalled on an arm 22 for variable position thereon. Arm 12 is secured to the housing for the drum 1.
In particular, a journal box 23 for pulley 12 may be geared to drum 1, using a worm gear 24, having pitch corresponding to half the length dimension to be compensated during one revolution of drum 1. Worm gear 24 will be driven by and from drum 1 through appropriate gearing. The displacement of pulley 12 is, thus, proportioned to take up the difference in length reeled as to cables/ropes 3 and 4 during reeling action by the drum. It can, thus, be seen that the pulley 12 on arm 22 establishes a loop for cable/rope 4 which is enlarged upon unwinding the cables/ropes 3 and 4 from drum 1, so that the lengths of the two cables or ropes as passing over pulley 11 are the same. For reasons of symmetry, the arrangement can be duplicated as far as suspension of the cage 2 is concerned, and as was shown generally in FIG. 1.
Instead of driving the journal box directly from the rotation of drum 1, length compensating displacement of pulley 12 may be established through servo motors or pneumatic or hydraulic motors etc.
FIG. 6 shows again a reeling drum 1, a boom arm 10 with pulley 11 and load and safety cables or ropes 3 and 4. The cables/ropes 3 and 4 are wound onto drum 1 as indicated in FIG. 2. The difference in reeled length for each revolution of drum 1 is compensated here by an auxiliary boom 14 carrying a pulley 13 particularly guiding safety cable/rope 4. The arm 14 is pivoted on the housing. Pivot action may be established, for example, through a servo motor 26 or the like, operating in response to constant (but normally not load bearing) tension on safety cable/rope 4.
The dash-dot circle in FIG. 6 denotes the arc along which the center of pulley 13 can be displaced upon pivoting arm 14. Accordingly, the supplemental loop of cable/rope 4 outside of drum 1 and extending between the run-off point from drum 1 and pulley 11 is shortened on couterclockwise movement of the pulley 13 on the dash-dot circle. As a consequence, a certain amount of length of cable/rope 4 is added to the length that is hoisted upon lifting cage 2, so that different length of cables 3 and 4 can be wound onto drum 1, needed for the different reeling diameters. The arm 14 pivots slowly up (or down in case of unwinding cables from the drum) so that the total amounts of the two cables, as passing pulley 11 in either direction, are similar.
It can thus be seen that in either example a temporary storage facility permits the different reeling lengths to be equalized on the cage, so that any shift in load from one cable to the other is not accompanied by a sudden change in suspension length. The cage will not seek suddenly a different level of suspension.
The invention is not limited to the embodiments described above but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be included.