HANDLING SYSTEM

Technical field

This invention relates to a handling system .

In particular, the invention relates to a handling system of the type comprising a threaded bar and a nut engaged and movable on it .

Background art

These handling systems are usually used for moving a load from a surface to a higher surface , and vice versa . Handling systems are used both in industrial and other context s , for example residential , as in the case of elevators or lift s .

The prior art includes solutions which comprise the use of a mechanism comprising a threaded bar on which a recirculating ball screw nut is inserted .

Such a coupling is generally of the reversible type , that is to say, such that the nut slides along the axis of the worm screw mechanism, and such that , in order to descend, the nut does not need to be fed by transmis sion means , as it is pos sible to use the weight , that is , the force of gravity .

In the case of the elevator or lift , a recirculating ball screw nut allows the movement of the elevator/ lift cabin both upwards and downwards , in a reversible fashion .

However, these couplings have drawbacks .

A ma j or drawback is due to the fact that the nut s used in the prior art systems undergo elastic deformation during use due to working stres ses under load . The elastic deformations under load, in particular of the housing holding the nut , means that only some of the spheres contained in the nut support the nominal load planned for each of them, whilst the other spheres of the nut are sub j ected to progres sively smaller loads .

Since this circumstance depends both on the elastic deformation of the materials with which the nut and the threaded bar are made , and on any manufacturing defect s , it is not easily avoided without changing the construction architecture of the handling system as a whole or by increasing the level , and therefore the cost s , of precision of the system .

Aim of the invention

The aim of the invention is therefore to provide a handling system which is able to overcome the above- mentioned drawbacks of the prior art .

A further aim of the invention is to provide a handling system in which it is pos sible to sub j ect all the spheres of the nut to the nominal load, thereby optimising the overall number of spheres of the nut with the same load which can be supported by the handling system it self and providing a system which does not have an limit greater than the capacity of a nut .

A further aim of the invention is to provide a handling system which can use threaded bars obtained by rolling and not sub j ected to costly surface finishing .

A further aim of the invention is to provide a handling system which is at the same time practical to use and simple and inexpensive to make . According to the invention, these aims and others are achieved by a handling system comprising the technical features described in the accompanying claims .

Brief description of the drawings

The technical features of the invention, with reference to the above-mentioned aims , are clearly described in the appended claims and it s advantages are apparent from the detailed description which follows , with reference to the accompanying drawings which illustrate purely non-limiting example embodiment s of the invention, in which :

- Figure 1 is a schematic perspective view of an embodiment of the handling system according to the invention ;

- Figure 2 is a schematic top view partly in cros s section of the handling system of Figure 1 ;

- Figure 3 is a schematic bottom view partly cros s section of a sphere-holder skid in accordance with the handling system according to the invention ;

- Figure 4 is a schematic side view partly in cros s section of the skid of Figure 3 operatively connected to the threaded bar of the handling system according to this invention and

- Figure 5 is a top view in cros s section of a skid according to the invention .

With reference to the accompanying drawings , the numeral 1 denotes in it s entirety a handling system made in accordance with the invention, hereinafter also referred to simply as the system 1 .

Detailed description Advantageously, the direction of movement is defined as vertical with respect to a horizontal plane or the ground but it is pos sible to use the handling system 1 according to the invention for moving loads in directions in any way inclined or parallel to a horizontal plane or the ground .

With reference to the accompanying drawings , the handling system 1 according to the invention comprises a threaded bar 2 having a main axis of extension A and a nut 3 configured to engage by screwing with the threaded bar 2 .

The nut 3 is therefore able to move relative to the bar 2 along the axis A .

According to a first embodiment , the nut 3 moves axially following a rotation of the threaded bar 2 , that is to say, it is the threaded bar 2 to be connected to a drive motor, not illustrated in the drawings .

According to a second embodiment , on the other hand, the bar 2 moves axially following a rotation of the nut 3 , that is to say, the nut 3 is connected to a drive motor, not illustrated in the drawings .

The nut 3 engages with the threaded bar 2 by means of a plurality of spheres 4 which are designed to roll on the thread 9 of the bar 2 .

The system 1 comprises a plurality of skids 5 for containing the spheres 4 which are positioned angularly distributed on the nut 3 and advantageously according to the inclination of the thread of the threaded bar 2 on which they engage . As shown in Figure 2 , the skids are distributed in a radial fashion, which has as the centre the main axis of extension A of the threaded bar 2 .

In this way it is pos sible to optimise the equal distribution of the load on each single skid 5 of the nut .

Advantageously, the nut 3 comprises a plurality of seat s 6 , which are also angularly distributed in a radial fashion, having as the centre the main axis of extension A of the threaded bar 2 .

The seat s 6 are designed to contain the skids 5 .

Advantageously, both the skids 5 and the respective seat s 6 are positioned angularly equally distributed on the nut 3 .

In particular, each seat 6 corresponds to a respective skid 5 which, during operation of the handling system 1 , is inserted and retained in the respective seat 6 .

The skids 5 are held in the respective seat s 6 by locking means , for example a threaded grub screw, not illustrated in the drawings .

Both the seat s 6 and, therefore , the skids 5 are positioned in a plane substantially perpendicular to the main axis of extension A of the threaded bar 2 .

The term substant ially perpendicular means a plane which follows the inclination of the thread 9 of the threaded bar 2 .

According to this embodiment , the seat s 6 and the respective skids 5 are arranged in a spiral on the nut 3 .

Advantageously, the skids 5 can be removed with respect to the respective seat s 6 , which allows , for example , maintenance operations to be performed quickly and easily by simply extracting one or more skids 5 from the respective seat s 6 .

Advantageously, moreover, the seat s 6 have a cylindrical shape and the skids 5 have a portion shaped to match a respective seat 6 for allowing at least an oscillation of the skids 5 relative to the nut 3 .

The above-mentioned oscillation is due to a rotation of the skids 5 with respect to the relative B .

The axis B is perpendicular to the main axis of extension A of the threaded bar 2 .

The oscillation makes it pos sible to obtain an adjustment of the position of the skids 5 , and in particular of the spheres 4 held inside them, with respect to the trend/ inclinat ion of the thread 9 of the bar 2 .

The above-mentioned oscillation of each single skid 5 in the relative seat 6 allows automatic adaptation of the skid 5 to threaded bars 2 having dif ferent angles of inclination of the spiral (thread) .

The advantage achieved is that a same skid 5 may be used on threaded bars 2 having dif ferent threads and/or dif ferent diameters .

The system 1 al so comprises a deformable element 7 elastically interposed between the seat s 6 and the respective skids 5 .

According to the embodiment shown in Figures 1 and 4 the elastically deformable element 7 is positioned integral with a portion of each of the skids 5 .

Alternatively, or in addition, the deformable element 7 is positioned integral with an inner surface of each of the seat s 6 (this embodiment is not shown in the drawings ) .

Both solutions allow an ef fect of suspension and damping of the movement of the single skid 5 with respect to the relative seat 6 to be obtained .

This damping make s it pos sible to overcome , for example , any manufacturing defect s of the threaded bar 2 , for example in the case of bars 2 made by rolling, or bars added to increase the length, or any elastic deformations of the bar, or of the nut 3 , during operation .

The presence of a deformable element 7 for each single skid 5 makes it pos sible to obtain a secure distribution of the load to which the nut 3 is sub j ected equally distributed on all the skids 5 and, therefore , on all the spheres 4 .

With reference to Figures 2 , 3 and 4 , each skid 5 comprises an internal channel 8 for housing and recirculating a plurality of the above-mentioned spheres 4 .

For example , each skid 5 comprises seven spheres 4 of which, during operation, two always in contact with the portion of thread 9 of the bar 2 .

The spheres 4 are designed to roll on the portion of thread 9 of the bar 2 and circulate inside the channel 8 of the respective skid .

This solution makes it pos sible to obtain an equal distribution of the loads on each single sphere 4 of a single skid 5 and, therefore , an equal "aging" of all the spheres 4 of a single skid 5 .

Advantageously, as shown in Figure 4 , each skid 5 comprises a retaining unit 10 configured to prevent the escape of the spheres 4 from the channel 8 when the skid 5 is extracted from the respective seat 6 .

The skids 5 may also, individually, be removed from the respective seat s 6 even when the nut 3 is under load .

This makes it pos sible to easily perform maintenance operations on the individual skids 5 without having to remove the nut 3 from the threaded bar 2 , which is an operation that would be very expensive since it would result in the stoppage of the entire handling system 1 . The skids 5 comprise two semi-portions which are j oined to each other to form the body of the skid 5 .

More in detail , the skid 5 comprises a lower portion 11 designed for centring with respect to the respective seat and an upper portion 12 designed to contain the recirculation channel 8 of the spheres . The two portions 11 , 12 form a cylinder when coupled .

Figure 5 shows a view from below in cros s section of a skid 5 which indicates a loading portion 20 ( dashed line ) of the spheres 4 when they are in contact with the thread of the respective threaded bar 2 and transmit the load to it .

In particular, the shape of the recirculating channel 8 for the spheres 4 inside the skid 5 is such as to allow the spheres 4 under load, that is to say, those pas sing from the loading portion 20 , and only them, to freely travel along reasonably dif ferent tra j ectories .

As shown in Figure 5 , the spheres 4 under load can be positioned, when inside the portion 20 , in at least two positions 20a, 20b ( and all the multiple intermediate positions ) of the channel 8 . Figure 5 also schematically illustrates a portion 21 which corresponds to the area where all the pos sible tra j ectories which can be followed by the spheres 4 of a single skid 5 lie .

Each tra j ectory travelled by the spheres 4 corresponds to a diameter of the threaded bar 2 .

It is understood that when the diameter of the threaded bar 2 is varied, the diameter of the nut 3 which can be coupled with it also varies .

The advantage is that it is pos sible to use the same skid 5 with nut s 3 and respective threaded bars 2 having even very dif ferent diameters .

The handling system 1 according to the invention achieves the preset aims and brings further important advantages . A first advantage of the handling system 1 according to the invention is the pos sibility of using threaded bars 2 obtained, for example , by rolling, which are more economical than those which are more finished and precise .

This is because each single skid 5 can be adapted to any imperfections of geometry of the threaded bar 2 and/or of the nut 3 .

Another advantage of the handling system 1 according to invention is due to the fact that each skid 5 always uses only two spheres 4 loaded by the threaded bar 2 at their nominal load .

This means that all the pairs of spheres 4 of all the skids 5 are loaded at the relative nominal load, that is to say, they are used to their maximum potential .

Since , therefore , all the spheres 4 are loaded in an equal and optimum manner and since there is no partly loaded sphere , with the same load required of the handling system 1 , this comprises an overall number of spheres 4 which are optimum, and not over-sized as in the prior art . Another advantage of the handling system 1 according to the invention is due to the fact that , since each single skid 5 ( and hence the relative spheres 4 ) is independent of the remaining skids 5 of the nut , each of them is able to adapt to the portion of thread of the threaded bar 2 which it touches without being influenced during operation by the remaining spheres 4 and/or skids 5 of the nut 3 .