GB2048201A

GB2048201A - Rope hoist

Info

Publication number: GB2048201A
Application number: GB8003984A
Authority: GB
Original assignee: Carruthers & Co J H
Current assignee: Carruthers & Co J H
Priority date: 1979-02-07
Filing date: 1980-02-06
Publication date: 1980-12-10

Abstract

A reduction in the overall dimensions and particularly in the axial length of an electric rope hoist is obtained by rotatably mounting the winding drum 1 in annular end supports 3, 4 and housing in the drum an electric motor having a tubular casing 2, which is mounted at one end on one of the end supports 3, and projects cantilever-fashion into the drum. The rotor/stator assembly 10, 11, in the casing 2, includes a pair of opposed shaft portions 7A, 7B, the one at the free end of the casing being drivingly connected through gearing 20, 21, 22, 24, to the adjacent end of the drum and the one at the mounted end of the casing being associated with electrically operable braking means 12, 13, including a brake actuator 17, disposed wholly within the casing. With the motor and the braking means including the braking actuator telescoped wholly within the drum the overall size of the hoist can be substantially reduced. <IMAGE>

Description

Improvements in or relating to electric rope hoists This invention relates to electrical rope hoists.

In a usual form of electrical rope hoist the rope drum has at one end thereof an electric motor with associated braking means, and at the other end thereof reduction gearing drivingly connected thereto, the gearing being connected to the motor shaft by a drive shaft extending axially through the rope drum. With the rope drum, motor and gearing so arranged in axial series, the overall length of the hoist is considerable; thus, the overall length of say a 5 ton hoist built in the aforesaid manner is usually in the region of 4,000 mm.

The chief object of the present invention is to reduce substantially the total volume, particularly the overall axial length, of electric rope hoists.

According to the present invention we provide a rope hoist comprising a pair of spaced annular end supports, a winding drum rotatably mounted at its ends in the end supports, an electric motor having a tubular casing whereof an end is mounted on one of the end supports so that the casing projects within the drum, a rotor-stator assembly in the casing, and a shaft portion at the side of the assembly remote from the mounted end of the casing, and gearing connecting the shaft portion to the adjacent end of the drum so that the motor drives the drum.

Preferably the motor has a second shaft portion at the side of the assembly adjacent to the mounted end of the casing, and electrically operable braking means are provided in the casing at the mounted end thereof and are operatively connected to the second shaft portion.

The following are advantageous features any or all of which can readily be embodied in the basic electrical rope hoist according to the present invention: (i) Cooling means are provided comprising air openings in the drum wall at the end of the wall adjacent to the gearing, air openings in the casing wall at the end of the wall adjacent to the braking means, and a fan at the end of the motor casing to create a flow of air axially into the casing and axially through an annular space between drum and casing. The braking means and the motor windings are thus cooled by heat exchange through the casing wall. With such efficient lowcost cooling, the fan can be kept running when the hoist is connected to the power source but is not being operated.

(ii) The shaft portions are rotatably supported in a pair of bearings carried by respectively the casing and the drum.

(iii) The gearing consists of epicyclic gearing including a toothed annulus on the annular end support and a toothed annulus on the drum.

(iv) The braking-means include a multi-disc device spring-urged to release position and electromagnetic actuating means associated with the device to move same to operative position against spring action.

By virtue of the present invention it becomes possible to construct an electrical rope hoist with an occupied volume representing in the region of 30% of the occupied volume of the aforesaid usual form of electrical rope hoist. By contrast with the overall axial length (4,000 mm) of the aforesaid usual form of electrical rope hoist, the overall axial length of the machine of the present invention is a mere 1,250 mm. With the resulting economies in the scale and number of component parts, the hoist of the present invention has better user capability but at no greater manufacturing cost.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a side elevation of an electric wire-rope hoist, including a rope-tensioning device, Fig. 2 is an end view of the hoist in the direction of arrow II in Fig. 1, Fig. 3 is a sectional side elevation of the hoist of Fig. 1, Fig. 4 is a top plan view of the rope-tensioning device of Fig. 1, Fig. 5 is a fragmentary part-sectional top plan view of the rope-tensioning device of Fig. 1, and Fig. 6 is a transverse sectional view on the line VI--VI of Fig. 5.

Referring to the drawings: In an electric wire-rope hoist, the rope drum 1 and the motor casing 2 are generally cylindrical.

The rope drum 1 is rotatably mounted in annular end bearings 3 and 4 extending around the drum periphery and carried by a pair of spaced interconnected annular end supports 5 and 6.

The motor casing 2 has therein, in series (a) a shaft 7 mounted in bearings 8 and 9, (b) rotor/stator means 10, 11 on and around the shaft 7 which has portions 7A and 7B thereof projecting from opposite sides of the rotor, (c) a multi-disc braking device including rotary friction discs 12 keyed on the shaft portion 7A and reciprocable discs 13 and urged by springs 14 to brake release position and (d) electromagnetic brake-actuating means including a reciprocable thrust plate 1 5 urged by springs 1 6 against the adjacent disc 1 3 to effect braking of the shaft 7, and an electromagnetic actuator 1 7 associated with the thrust plate 1 5 and energizable with the motor to draw the thrust plate to brake-release position against the action of the springs 1 6. On deenergization of the motor, the actuator 1 7 de energizes and the thrust plate moves to brake the motor shaft.

The motor casing 2 at the end thereof adjacent to the electromagnetic means 1 7 is mounted on the end support 5 and projects in the manner of a cantilever coaxially within and is spaced from the rope drum 1 so as to form with the rope drum a double-walied housing. The composite housing contains the shaft bearings 8 and 9, the bearings 8 being carried by a radial spider 1 8 in the bore of the motor casing 2, and the bearing 9 being carried by a transverse wall 1 9 in the bore of the rope drum 1.

Epicyclic reduction gearing is mounted on and around the shaft portion 7B and includes a sun pinion 20 keyed on the shaft portion 7A, a toothed annulus 21 fixed on the adjacent end support 6, planet gears 22 on a carrier 23 on the shaft portion 7B, and a toothed annulus 24 forming an end portion of the rope drum 1. Said reduction gearing drivingly connects the shaft 7 to the periphery of the rope drum 1. A fan 25 on the end support 5 is coaxial with the shaft 7 and covers the adjacent end of the motor casing 2.Openings 26 are provided in the rope drum 1 at the end thereof adjacent to the epicyclic gearing, and openings 27 are provided in the motor casing 2 at the end thereof adjacent to the electromagnetic means 1 7. The fan creates an axial flow of cooling air into the motor casing 2 and through the interwall space 28 of the composite housing 1, 2, the air entering the space 28 through the openings 27 and discharging to atmosphere through the openings 26. Air cooling of the mechanical brake and the motor windings is thus effected by heat-exchange through the motor casings 2.

The hoist includes also a rope-tensioning assembly 28 (Fig. 1) adjacent to the drum 1. This assembly ensures correct laying of the wire rope on to the drum for storage purposes by maintaining at all times sufficient tension on the upper rope length 29 adjacent to the drum to prevent springing of the coils 31 of stored rope away from the drum when the lower rope length 30 tends to spring upwards following removal of the load from the rope. Entanglement of rope coils 31 laid in multiple layers on the drum is thus avoided.The assembly includes a tubular housing 32 extending between end plates of the hoist, a screw-threaded (archimedes) shaft 33 extending coaxially through the housing 32 and rotatable in end bearings 34 and 35 carried by the end plates, and a drive connecting an end of the motor shaft with the adjacent end of the shaft 33, said drive including belt-and-pulley gearing 36 and a reduction gear box 37. A rope-tensioning device 38 is mounted for reciprocation on the housing 32 and includes a sleeve portion 39 enclosing the housing 32, a pair of spaced radial arms 40, 41 on the sleeve portions 39, and a set of rope-engaging rollers 42 disposed between and rotatably mounted on the arms 40,41.A square bush 43 projecting into the sleeve portion 38slidingly engages in an axial slot 44 in the housing 32 and carries in its cylindrical bore a pin 45 which terminates in a nut formation 46 engaging the screw-threads 47 of the shaft 33 so that unidirectional rotation of the shaft 33 effects axial reciprocation of the tensioning device 38 concomitantly with the axial reciprocation of the rope as the latter leaves and approaches the drum.

The set of rope-engaging rollers 42 includes a pair of top and bottom rollers 48 and 49 and an intermediate roller 50 mounted for reciprocation towards and from the rollers 48, 49. The three rollers are mounted on pins 51, 52 and 53 whereof the ends project laterally beyond the arms 41,42 and pairs of tensioning springs 54, 54A and 55, 55A connect the ends of the pin 53 with the ends of the pins 51 and 52. The pin 53 of the roller 50 is slidable in slots 40A, 41A in the arms 40, 41 so that the tensioning springs urge the roller 50 towards the rollers 48, 49 to form a bend in the rope in its passage through the set of rollers.

With the opposed rollers of the set resiliently gripping the rope between them upwards springing movement of the lower length 30 of the rope following removal of the load is prevented so that there is no loosening of the coils 31 on the drum and correct storage of the rope on the drum is maintained.

Claims

1. A rope hoist comprising a pair of spaced annular end supports, a winding drum rotatably mounted at its ends in the end supports, an electric motor having a tubular casing whereof an end is mounted on one of the end supports so that the casing projects within the drum, a rotor/stator assembly in the casing, and a shaft portion at the side of the assembly remote from the mounted end of the casing, and gearing connecting the shaft portion of the adjacent end of the drum so that the motor drives the drum.

2. A rope hoist according to claim 1 ,wherein the gearing consists of epicyclic gearing including a toothed annulus on the adjacent annular end support and a toothed annul us on the adjacent end of the drum.

3. A rope hoist according to claim 1 or 2, wherein the motor has a second shaft portion at the side of the assembly adjacent to the mounted end of the casing, and electrically operable braking means are provided in the casing at the mounted end thereof and are operatively connected to the second shaft portion.

4. A rope hoist according to claim 3, wherein the shaft portions are rotatably mounted on a pair of bearings carried respectively by the casing and by the drum.

5. A rope hoist according to claim 3 or 4, including cooling means comprising ducting formed by an air opening in the drum wall at the end of the wail adjacent to the gearing, an air opening in the casing wall at the end of the wall adjacent to the braking means, and an annular air space between the drum wall and the casing wall, and a fan at the mounted end of the casing operable to create an air flow through the ducting and thereby cool the braking means and the assembly by heat exchange through the casing wall.

6. A rope hoist according to claims 3 or 4 or 5, wherein the braking means include a multi-disc device spring-urged to release position and electromagnetic actuating means associated with the device to move same to operative position against spring action.

7. A rope hoist according to any one of the preceding claims, including a rope-tensioning device mounted alongside the drum for axial reciprocation concomitant with the rotation of the drum and having opposed rollers adapted to grip a wire rope resiliently between them so that the device follows the axial reciprocation of the rope during operation of the hoist and the rollers in gripping the rope to prevent springing of the rope coils from the drum periphery on removal of load from the rope.

8. A rope hoist substantially as hereinbefore described with reference to the accompanying drawings.