LOAD TRANSFER APPARATUS

Abstract: A screw and nut drive mechanism. The mechanism comprises a motor (16), a gearbox (18) having a hollow output shaft (19), a coupling (17) coupling the motor to the gearbox, a fixed screw (10) disposed to pass with a clearance through the hollow shaft and in threaded engagement with a nut (10a) rigidly attached to an end of the shaft. Rotation of the shaft rotates the nut causing the nut (and associated sub-base (15)) to move up and down the screw. The mechanism is intended to serve as a drive for an elevator with the sub-base being attached to a cantilevered frame from which the elevator car or carriage is suspended.

Description: LOAD TRANSFER APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inducing controlled and variable relative movement " between two threaded members. The invention further relates to a particular usage for such an apparatus, namely in an apparat to be employed in the transfer of loads between vertically spaced-apart levels (floors or storeys) of a building or the like structure. 2. Description of the Prior Art Nowadays, common usage is made of such equipment as elevators for the transfer of loads (passengers and/or freigh between different levels (storeys) in a building, warehouse or the like. What may be termed conventional elevators, of t type suitable for transferring loads from one level to anothe depend for their actual operation upon the utilisation of ste cables, hoisting ropes or the like. Such elevators in genera may be see to comprise a power-operated device for lifting and lowering loads and are made up of a so-called car or cage which is arranged so as to run between guide rails extending between the levels under consideration. The car or cage itse is by convention suspended from steel hoisting ropes or cable The weight of the car and its load is, in practice, approx- inately counter-balanced by a so-called counterweight. The actual weight to be hoisted or transferred between levels may therefore be seen never to equal the total weight of the car and passengers (or load) but rather is equal to merely the relatively small difference which exists between the counter- weight and the weight of the loaded car. Such conventional elevators have been found to suffer from a number of drawbacks in terms of their actual complexit the need for various safety devices which must come into operation in the event of power failure or other breakdown, and also on the basis of considerations such as actual spatia reαuirements for the overall construction. OMPI By reason of the use of steel hoisting cables, ropes and the like the relevant government authorities require the incorporation of sophisticated and virtually fail-safe safety devices and safe-guards in elevators of this general type. Conventional elevators of this general type rely on electric motors and the like for the hoisting operation. Power take-off and transmission from such motors is, by convention, achieved by the use of belts, sprockets, etc. Such belts, sprockets etc. in themselves constitute another possible source of break-down or potentially catastrophic failure, again therefore necessitating the utilization of fail-safe, back-up devices. Further problems arise when an elevator is specifical required, for example, for use and installation in a two- storey building, be that building a private house, flats, offices or perhaps even storage facilities. I-Iodern elevators are particularly designed for usage in ulti (more than two)- storey buildings and, in the result, it is generally extremel difficult and accordingly -expensive to obtain a smaller unit for usage in a two-storey situation, or alternatively for use between any two vertically adjacent storeys. As pointed out above such smaller units may be required, for example, by smaller firms for the purposes of transporting loads, in the form of personnel, stationery and/or other material between adjacent floors. Alternatively, in the domestic situation, such small units would be particularly appropriate for the transport of either elderly or otherwise incapacitated people between adjacent floors of a multi-storey home or building. If no such facility for transport is provided, then such elderly or incapacitated people would in essence be virtually confined to a particular storey of the structure, a dreary existence indeed. SIΓ- ARY OF THE INVENTION The present invention seeks to provide an apparatus for inducing controlled and variable relative movement betwee two threaded members, with such apparatus being particularly suited for use in or as part of a drive means for an elevator of the aforementioned type (for movement of loads between spaced apart levels of a building or the like structure). The present invention further seeks to provide an elevator or load transfer means which is particularly suited for usage between adjacent levels in a structure. The invention further seeks to provide such a load transfer means or elevator which achieves the desired result in an efficient manner and by the utilisation of apparatus the cos of which brings it within reach of both the business and domestic sections of our community. The present applicant's arrangement seeks to avoid t need for the use of ropes, cables and the like in elevator o load transfer equipment, and also to eliminate the need for the use of belts, drive sprockets etc. in the power source thereof. The present arrangement, by eliminating the need for these elements, results in an increase in both the efficiency of the overall system and the degree of safety afforded thereby. Despite the elimination of such elements, the present applicant's arrangement .has nevertheless been found to comply fully with the requirements of the relevant government authority or instrumentality as regards structura and operational safety. The present invention further seeks to provide an elevator which will not drop in the event of power failure, but will rather automatically stop at the level reached or attained at that particular point of time. The present invention furthermore seeks to provide an elevator or load transfer means which is adaptable for ready installation into an existing building, or alternatively may be readily fitted to an outer wall of an existing building. In order to achieve this result, an elevator or load transfer means in accordance with the present invention is adapted for assembly prior to transport to the site where installation is required. In accordance with a first aspect of the present invention there is provided apparatus for inducing controlled and variable relative movement between two threaded members, f OMPI said apparatus including drive means and associated connecte power transmission means, an output shaft of said drive mean being co-incident with the input shaft of said power trans¬ mission means, wherein an output shaft of and extending through said power transmission means is hollow and is adapted to have disposed therethrough and spaced therefrom a first of said threaded members, the other said threaded member being rigidly connected to said hollow shaft such that rotation of said output shaft induces relative movement between said two threaded members. In accordance with a further aspect of the present invention there is provided a self-supporting and self- contained apparatus capable of being preassembled and locate in an existing well or space provided in a building or the like structure, said apparatus being for the transfer of loads between vertically spaced-apart levels of said structure, said apparatus including: (a) support frame means; (b) carriage means adapted for movement between said spaced-apart levels of said structure, said carriage means being disposed in cantilevered relationship to said support frame means; (c) platform means for supporting a load, said platform means being suspended from said carriage means; (d) an elongated, stationary screw extending longitud¬ inally of said support frame means and rigidly affixed thereto at or in the vicinity of both ends thereof, said screw being threaded within a revolving, circulating ball nut; and (e) apparatus of the type as set out in the preceding paragraph. BRIEF DESCRIPTION CF THE DRA ING-S In order that the present invention may be more * clearly understood and put into practical effect there shall now be described in detail preferred constructions of a load transfer means in accordance with the invention. The OMPI v IPO ensuing description is given by way of non-limitative example only and is with reference to the accompanying drawings, wherein; Figure 1 is a perspective view of a load transfer apparatus in accordance with the invention; Figure 2 is a side elevational view of a drive assembly for the apparatus of Figure 1; Figure 3 is a top plan view of the apparatus of Figure 1; and Figure 4 is a side elevational view of the apparatus of Figure 1, with the load transfer apparatus in its upper¬ most position. DESCRIPTION OF THE PREFERRED BI-B0DII3NT In the preferred embodiment illustrated a load transfer a p paratus in accordance with the invention includes a tower or support frame 1 adapted to extend between levels a building or the like. The tower 1 in effect defines the total spatial requirements for the overall apparatus, with all other components of and for the apparatus being in fact confined within the interior of that tower 1. The transfer means thus arranged may be of a modular construction, whereb to allow for transport in its assembled condition to a site for installation in the interior of a building, or alter¬ natively for ready attachment to the side of a building. The apparatus as illustrated further includes a carriage and drive base assembly 2, preferably of a cant¬ ilevered form. Adapted to be suspended from this cantilevere carriage and drive base assembly 2, in any known manner, is a load-carrying platform, preferably in the form of a car or cage 3. In the especially preferred embodiment illustrate the car or cage 3 is supported by means of a support sling 4 adapted to extend downwardly from and to be affixed (in any known manner) to the cantilevered carriage and drive base assembly 2. However, it should be understood that other means are possible for suspending the car or cage 3 in the desired position. Preferably, the car or cage 3 has associated BAD ORIGINAL β. therewith means allowing for ready access thereto, with such means taking the form of at least one door sill and frame assembly 5 and an associated sliding door arrange¬ ment 6. In the embodiment illustrated there are provided two such door sills and frames 5 and associated doors 6 disposed, on opposite sides of the car or cage 3. However it should be understood that the apparatus in accordance with the present invention could include only one such sill and door assembly, or alternatively be provided with equivalent door and sill assemblies on at least three sides thereof. In other words, the car or cage 3 ~~~ s.J be provided as a so-called comeback model having doors to one side only, as a so-called walk-through unit having doors on two opposed sides thereof, or alternatively having doors on three sides thereof. Insofar as the doors themselves are concerned, the or each door 6 may be either on a hand-operated or self- opening type, as is the wont of the purchaser of the overall assembly. In the preferred embodiment illustrated, the apparatus includes what may be termed two-speed, self-opening sliding doors 6 for the car or cage 3. In an especially preferred embodiment the or each doo 6 of the car or cage 3 is fabricated from aluminium and mild steel sections as a separate unit to be bolted or otherwise affixed to the car or cage 3. If a hand-operated door is desired, this may be achieved by the provision of an approp¬ riately fire-rated door arranged on a so-called Bangor type track and counter-weighted with a dash-pot arrangement. However, if self-opening type doors are desired this may be achieved by fitting the or each door with a torque limited drive. In addition to the aforementioned door or doors on the car or cage 3 » in accordance with the present invention there is also preferably provided, at each level or landing of the building or the like structure at which the car or cage 3 is to stop, an outer or landing door assembly 7 associated with the tower 1. This landing door assembly 7 may be of a somewhat similar construction to the various doors of the actual car or cage 3, although preferably the landing door assembly 7 is adapted to be bolted or otherwise affixed to the tower 1 and to be fitted with a lock of the so-called electro-mechanical type whereby to prevent unauthorised or undesirable opening thereof at any time when the car or cage 3 is not in itself present at the particular level or landing concerned. Such an arrangement in fact constitutes a further safety precaution. The landing door assembly 7 may also be provided with a technician's lock release assembly whereby to allow ready access thereto as for purposes of service and/or maintenance. The carriage and drive base assembly 2 as illustrate furthermore has associated therewith means allowing for guidance of the car or cage 3 along a predetermined path in the tower 1. In the particular embodiment illustrated such guidance is achieved through the interaction of travers ing gibs 8 and complementary-shaped channel guides 9 extending in the vertical direction of the tower 1, with at least one of said traversing gibs 8 being located on opposit upper corners of the drive base assembly 2 and associated guides 9 being located on opposite sides of the tower 1. In an alternative embodiment this same result may be achieve by means of at least one, and preferably two, guide wheels or rollers located on opposed sides of the cantilevered carriage and drive base assembly 2, with each guide wheel or roller being adapted to co-operate with a complementary- shaped guide rail, in the form of a channel member, extendin in the vertical direction of the tower 1. In the particular embodiment illustrated, in order to allow for movement of the car or cage 3 in the tower 1, in a vertically upward or downward direction as desired, there is provided a so-called recirculating ball screw and nut assembly sited preferably midway between said guides 9. Such a recirculating ball screw and nut assembly will include a recirculating ball screw 10, of the so-called Sa inaw OMP type, having a revolving circulating ball nut associated therewith. In the embodiment illustrated the recirculating ball screw 10 is attached or affixed to the carriage and drive base assembly 2 by means of a carrier bracket 11. At the uppermost end thereof, the recirculating ball screw 10 is secured relative to the tower 1 by means of an upper carrier bracket 12 (in any known manner). It should be understood, however, that alternative arrangements are possible for achieving such fixing or securing relative to the tower 1. As may be seen, the tower 1 may be provided with lateral ties and bracing members 13 and 14 at approp¬ riate positions thereon. As illustrated the carriage and drive base assembly 2 has associated therewith a drive sub-base 15, with that sub-base 15 having located thereon a drive motor 16, a solenoid braking means and drum coupling 17 and a reducing gearbox 18. Preferably the drive motor 16 will be in the form of a single phase motor connected, via a suitable power coupling, to a 90-degree reducing gearbox 18. In practice the solenoid braking means and drum coupling 17 will ensure that a short period of dwell will exist before the onset of what may be termed full torque to the reducing gearbox 18, thereby allowing for what may be termed, in layman's language a "soft" start-stop effect. In the embodiment illustrated (see FIG. 2) the gearbox 18 includes a hollow output shaft 19. The recircul¬ ating ball screw 10 is adapted to pass through that shaft 19 and to be affixed (in any known manner) to suitable mounting brackets located on the tower or support frame 1 at or in the vicinity of the top and bottom thereof. The nut 10a associated with, and adapted to move relative to, the recirculating ball screw 10 may then be operably connected to the hollow shaft of gearbox 18 in any known way, as for example by being threadably connected thereto. The arrange- ent is such that movement of the hollo ' output sha t 19 of gearbox 18 gives rise to equivalent movement (rotation) of the recirculating ball nut 10a relative to the fixed • "gJRE OM screw 10, thereby causing the nut 10a (and associated sub-base 15) to move upwardly and downwardly along the screw 10 as desired. Such a configuration allows for effectively direct coupling between the recirculating ball screw and nut assembly 10, 10a and the gearbox 18 and associated drive motor 16, thereby eliminating the need for equipment such as, for example, chains, belts and sprockets. The elimination of such equipment will, of course, simultan¬ eously eliminate a possible mode of breakdown of the load transfer apparatus, that is the occurrence of damage and/or breakage to the chains and/or sprockets. Preferably, a single-phase electric motor may be employed as the drive motor 16. However, and dependant on the intended usage, three-phase current may be employed, with the result that a three-phase motor may be appropriate in certain circumstances. As stated above, and for conven¬ ience of construction, not to mention ease of both maintenan and servicing, the drive motor 16, solenoid braking means an drum coupling 17 and reduction gearbox 18 are mounted on the drive sub-base 15 of the carriage and drive base assembly 2. However it should be noted that such items of equipment may alternatively be mounted on the top of the car or cage 3 itself. As a further safety precaution, additional braking means in the form of a so-called fail-safe disc brake may be associated with the recirculating ball screw and nut assembl 10, 10a. In order to allow for control of the overall system a number of control means, preferably electrical, may be provided. Such control means may include a demand button at each level of the building structure and a start-stop button in the car or cage 3 itself. In addition the tower 1 may be provided with so-called limit switches at each level or landing thereof, with such limit switches being operable to effectively de-energize the drive motor 16 upon arrival of the car or cage 3 at a respective or desired level or landing of the overall structure. Furthermore an appropriate D ORIGINAL (A, IFO communication system, as for example a telephone or the like, may be installed in the car or cage 3 whereby to allow for communication with persons outside the car or cage 3 » as for example in times of emergency. The aforegoing description may be seen to refer in some detail to what may be considered to be the basic features of the present applicant's arrangement. However it should be noted that a number of additional features may be included as desired, for purposes of overall safety and the comfort of the user. For example the car or cage 3 may be equipped with lighting of any known type. Preferably, however, all lightin and controls are of the low-voltage type. The car or cage 3 may also be equipped with a battery to operate as a stand-by to provide emergency lighting, as for example in the instance of power failure. Furthermore the or each entry door of the subject arrangement may be fitted with solenoid locks which are adapted to lock when de-energized such that, in the instance of power failure, entry cannot be gained unless the car or cage 3 is actually present at a level or landing. In a further preferred embodiment, buffers are fitted at the base of the tower 2 in order to protect against the possibility of over-run of the car 3. In addition, suitable anti-vibration mounts may be provided. The fail-safe disc brake associated with the recirculating ball screw and nut assembly 10, ICa may be in the form of a caliper-type disc brake. In the instance of power failure this disc brake will hold against release until actually released by a service man, or alternatively upon resumption of the power supply.

Claims: 1. Apparatus for inducing controlled and variable relative movement between two threaded members, said apparatus including drive means and associated connected power transmission means, an output shaft of said drive means being co-incident with the input shaft of said power transmission means, wherein an output shaft of and extend¬ ing through said power transmission means is hollow and is adapted to have disposed therethrough and spaced therefrom a first of said threaded members, the other said threaded member being rigidly connected to said hollow shaft such that rotation of said output shaft induces relative movement between said two threaded members. 2. Apparatus as claimed in claim 1, wherein said two threaded members are in the form of an elongated, vertically extending, stationary screw and an associated revolving circulating ball nut respectively, and said drive means and power transmission means are a motor and a gear-box coupled thereto, said input and output shafts of said power transmission means being disposed substantially at right angles to one another. 3. Apparatus as claimed in claim 2, wherein said motor and power transmission means are adapted for motion long¬ itudinally of said screws in response to movement of said revolving circulating ball nut relative to said screw. 4. A self-supporting and self contained apparatus capable of being preassembled and located in an existing well or space provided in a building or the like structure, said apparatus being for the transfer of loads between vertically spaced-apart levels of said structure, said apparatus including: (a) support frame means; (b) carriage means adapted for movement between said spaced-apart levels of said structure, said carriage means being disposed in cantilevered relationship to said support frame means; (c) platform means for supporting a load, said platform means being suspended from said carriage means; OMPI (d) an elongated, stationary screw extending longitudinally of said support frame means and rigidly affixed thereto at or in the vicinity of both ends thereof, said screw being threaded within a revolving, circulating ball nut; and (e) apparatus as claimed in any one of the preceding claims, said apparatus being disposed on said uppermost surface of said carriage means, the arrangement being such that movement of said nut relative to said stationary screw induces movement of said carriage means and associated platform means longitudinally of said support frame means and between said vertically spaced-apart levels. 5. Apparatus as claimed in claim 4, wherein said carriage means is in the form of an inverted substantially L-shaped structure adapted to be disposed within said support frame means for movement upwardly and downwardly therein as desired, said carriage means having associated therewith and extending downwardly therefrom means for receiving and retaining said platform means relative thereto. 6. Apparatus as claimed in claim 4 or 5, wherein said apparatus for inducing movement of said carriage means and platform means is disposed on the uppermost surface of said carriage means. 7. Apparatus as claimed in any one of claims 4 to 6, further including guide means for controlling the direction of movement of said carriage means and associated platform means, said guide means including at least two channel-form tracks rigidly affixed to said support frame means at opposite sides thereof, said channel-form tracks co-operating with complementary means provided on said carriage means. 8. Apparatus as claimed in claim 7, wherein said carriag means includes a plurality of rollers engaging said channel- form tracks whereby to control the direction of movement of said carriage means and associated platform means and prevent unwanted swaying thereof relative to said support frame means. -gTJRE OMPI • Q _? • Apparatus as claimed in any one of claims 4 to 8, wherein said platform means is in the form of a box¬ like cage or enclosure having a sliding-door arrangement provided on one or more sides thereof. 10. Apparatus as claimed in anj' one of claims 4 to 9, wherein said drive means is in the form of a single phase motor which is adapted to be connected, via power coupling means, to said power transmission means. 11. Apparatus as claimed in any one of claims 4 to 10, wherein said drive means is in the form of a three- phase motor which is adapted to be connected, via power coupling means, to said power transmission means.

Inventors: PERKINS R
Applicants: PERKINS R, SANSCORD AUSTRALIA PTY LTD
Application year: 1981
Main classification: B66B9
IPC codes: B66B9