To the purpose of more effectively exemplifying the present invention, the assumption is made according to which said outer casing is made of metal, and preferably of deep-drawn sheet-metal, while it will be appreciated that this by no means shall be intended to limit the scope of the present invention to just said kind of material and said kind of connection.

Compressor outer casings are known in the art to be provided with an inner body, ie. the functional part thereof, which is substantially formed by an electric motor provided with a stator and a related rotor, the assembly formed by the cylinder and the suction/compression piston, as well as the various associated and auxiliary elements and members.

Said inner body of the compressor rests inside the outer casing thereof by means of a plurality of elastic support means. More precisely, the whole inner body of the compressor is integral or is somehow joined with the stator of said

electric motor, said stator being in turn supported on the bottom of the outer casing in a any of a variety of methods. One among the most largely used methods relies on the use of following construction: on the bottom of the outer casing there are provided a plurality of resting or supporting means, which are usually formed by cylindrical or helical springs, which rise for a short distance above said bottom.

Between the upper portions of contiguous pairs of said elastic support means there are provided, and duly retained, horizontally extending elements, typically formed by narrow metal strips, which thereby form a bridge beteen said support means. All such bridges are therefore lifted from the bottom and elastically movable since they are supported by said elastic support means.

The stator stack is largely known to be held together by a plurality of screws passing through appropriate channels provided in the laminations of said stator stack, said through-screws, at their respective end portions facing the bottom of the outer casing, being fastened with per se known means to said strips so that the stator, and therefore the whole inner body of the compressor, is actually enabled to rest elastically on the bottom of the outer casing.

For a number of reasons, which are largely known to all those skilled in the art so that they do not actually need to be explained any further here, said support means are arranged in positions that are as close as possible to the vertical walls of the outer casing and, therefore, as far as possible from each other.

On the other hand, the dimensions of the stator stack are precisely defined by a number of both mechanical and electrical constraints, while it is also a largely known, obvious practice for said stator stack to be made as compact as possible.

It therefore ensues that the downward egression points of said screws retaining and holding together the stator stack are arranged inside the perimeter that is defined by the plurality of the above cited strips. For a connection of the stems to said strips to be enabled, the latter are provided with protrusions or projections extending inwards, so as to intercept and lock the screws of the stator.

Such a construction, ie. the presence of said strips between the support means and, furthermore, the appropriate manner in which said strips are shaped in order to enable them to be connected with the screws of the stator, implies overall manufacturing costs that are considered to be by all means too high in view of the function being performed by said construction which, it should be once again stressed, has actually to perform just a simple support task.

It would therefore be desirable, and it actually is a main purpose of the present invention to provide a compressor in which said characteristics pf elastic supension of the inner body thereof are anyway assured, but at a significantly reduced cost, with the use of readily available, state-of-art materials and techniques, while at the same time improving the assemblability.

The characteristics and features of the present invention are as recited in the appended claims The above aims are reached with the technical solutions that will be described below by way of non-limiting example with reference to the accompanying drawings, in which -Figure 1 is a front plan view of a lamination of a stator stack of a compressor according to the present invention; -Figure 2 is a vertical cross-sectional view of a compressor according to the present invention; -Figure 3 is a schematical perspective view of a stator stack of a compressor according to the present invention; -Figure 4 is a view of a detail of a constructive variant of a compressor according to the present invention.

The basic idea behind the present invention can be described as follows: with respect to the support structure of a stator 2 according to the state of the art, the elastic support means 3 are kept in their original position on the bottom 4 of the outer casing of the compressor, while the support strips joining in pairs said support means to each other, and which are engaged by appropriate through-passing elements performing the double task to holding together the stator stack and securing it firmly to said support strips, are on the contrary entirely eliminated.

As an alternative to the use of said strips, the laminations of the lower portion 5 of the stator stack are given a shape as substantially shown in particular in Figures 1 and 3, wherein the term lower portion is intended to mean a plurality of contiguous laminations which are arranged toward the bottom of the outer casing in close proximity of said support means.

With particular reference to Figure 1, the laminations illustrated there can be noticed to feature a plurality of axial perforations 21 adapted to accomodate the fastening and compacting tie-rods (not shown) that keep the laminations forming the stator stack appropriately compacted and tight.

The lamination illustrated in The Figure is further provided with some protrusions or appendices 6 that are in turn provided with respective through-holes 7.

As better illustrated in Figure 3, the. stator stack can be noticed to be formed by two portions or pluralities of laminations: the upper portion 11 is constituted by unmodified laminations of the same stator stack; the lower portion 5 is constituted by substantially identical larmnations as illustrated symbolically in Figure 1, ie. provided in all cases with at least an appendix 6 that protrudes outwards on the same plane as the respective lamination.

Said laminations of said lower portion are provided with a plurality of perforations 21 corresponding to the analogous perforations provided in the upper

portion for the passage therethrough of the tie-rods 13 provided for fastening and holding together the entire lamination stack; furthermore, the appendix 6 is provided with a respective perforation 7 situated in the same position in each mutually corresponding appendix, so that said plurality of perforations 7 of the appendices are able to form a channel passing vertically through said appendices.

The assembly of the stator stack takes place in the following manner: the laminations that are without appendices, and are identical to the laminations of the corresponding prior-art stator stack, are stacked to form the upper portion. The lower portion 5 of the stator stack according to the present invention is on the contrary formed only by laminations of the type illustrated in Figure 1.

The stator stack is then locked by means of a plurality of tie-rods 13, which pass through said axial perforations 21 that are common to both types of laminations used and thereby fasten and complete the stator stack.

The stator stack is then mounted on said elastic support means 3, wherein the geometry, ie. configuration, and the dimensions of the thereby involved elements are such as to ensure that the channel formed by said perforations 7 of the appendices comes to lie exactly above the resting area of said elastic support means 3. By means of engagement means 9 it is therefore possible for the lower portion 5 of the stator stack to be secured to said elastic support means and, owing to said stator stack being already so formed and consolidated, the whole stator stack is automatically locked in place on to said elastic support means and, therefore, to the bottom 4 of the outer casing of the compressor, as this is best shown in Figure 2.

The present invention also enables further variants and improvements to be implemented. For instance, a first variant resides in the fact that the laminations of the lower portion 5 may be provided with a single appendix 6 in the case that this is considered appropriate in view of an adequate reduction in costs, the other parts of the stator being therefore applied on to the bottom of the outer casing of the compressor according to the traditional, ie. prior-art means and methods.

It may on the other hand also prove advantageous, depending on the particular targets or options of the design engineer and the various technical and economic constraints, for a part or the totality of said elastic support means to be firmly associated to corresponding channels obtained by stacking, ie. superposing on each other, the perforations 7 provided in said lower portion 5 of the stator stack.

A second variant may reside in the fact that said engagement elements 3 are constituted by rivets that are headed on both ends thereof, ie. against the upper lamination 10 of said lower portion and, on the other side, against an appropriately provided undercut in the respectiveresting means 3.

In an advantageous manner, where the elastic means of said elastic support means 3 is constituted by a cylindric or helical spring, said undercut is formed by the last coil of said spring.

Such a circumstance would offer the advantage of significantly simplifying the overall construction owing to it enabling any further connection means, except for said rivet, to be prevented from being needed and used between spring and stator stack.

Furthermore, in view of making the construction of said stator stack more easily and efficiently processable, the laminations of said lower portion 5 of the stator stack may be processed in such a manner as to ensure that the respective appendices 6 and the related perforations 7 are, in each lamination, in the number of four and are position diagonally and/or symmetrically with respect to either the axis O of the stator or a vertical plane"A"crossing said axis.

A further variant, which is illustrated in Figure 4, refers to the manner in which said engagement means 9 are fastened to the respective elastic support means.

In this variant, said engagement means 9 is constituted by a rivet that is headed on both sides of the lower portion 5 of laminations; the lower heading 22 is much larger than actually needed to ensure the firmness of the rivet and, in particular, its

width is such as to enable it to be perfectly enveloped, practically with no slack or play at all, by the upper coils 10 of the helical spring 3, while its depth extends to reach at least the level of the second or successive coil 24.

In this manner, a safe, simple and very easily assemblable securing arrangement is obtained.

It will be appreciated that the description and illustrations set forth above with reference to the accompanying drawings have been given merely by way of non-limiting example of possible embodiments of the present invention, and that a number of further variants and modifications may therefore be developed without departing from the scope of the present invention.