Machine for the production of mattresses and method using the same

Abstract

The present invention concerns a machine (1 ) for the production of mattresses (7), comprising movement means (2), for the movement of an internal body (3) according to an advancement direction (A), wherein said machine (1 ) comprises at least one coating unit (4), in turn comprising at least one unwinding unit (41, 42, 43, 44, 45), for the application of a coating (412, 422, 432, 442, 452) on at least one respective surface (31, 32, 33, 34, 35, 36) of said internal body (3), while said internal body (3) is moved by said movement means (2). The present invention also concerns a method for coating an internal body (3).

Description

[0001] Machine for the production of mattresses and operating method of such a machine *****

[0002] The present invention concerns a machine for the production of mattresses and operating method of such machine.

[0003] Field of invention

[0004] Mor in detail, the invention concerns a machine of the aforementioned type, designed and realized in particular to automate the production of mattresses, but which can be used for any type of product to be packaged automatically.

[0005] In the following the description will be aimed at the production of pocket spring mattresses, but it is clear that the same should not be considered limited to this specific use.

[0006] Prior art

[0007] As is well known, there are different types of mattresses. In particular, mattresses are known which have an internal body to be covered, inserted inside a containment casing, or “box”, made of foam rubber plates. The internal body can be of different types, e.g., consisting of a plurality of pocket springs (also known as “pocket springs”), arranged as a matrix, so as to form a parallelepiped, with lateral faces or surfaces and front and rear surfaces, as mentioned, covered or lined with foam rubber plates. In other cases the internal body can be entirely made of foam, with LFK springs, Bonnell type or continuous wire springs.

[0008] The containment casing, however, is made of foam rubber plates, to allow the internal body to be housed.

[0009] In particular, the internal body has a parallelepiped shape and said foam rubber plates are cut and arranged so as to cover all the surfaces of the faces of the parallelepiped.

[0010] There are currently different types of machines for making mattresses, which to date are only partially automated. For example, there are machines that include a motorized table, for the transport of a lower or base foam rubber plate, on which, using motorized moving heads, strips of glue are applied, both on the perimeter and on the surface of a face.

[0011] Subsequently, this lower foam rubber plate is moved until it is placed on a working surface, where one, or generally two operators, arrange the lateral foam rubber plates, gluing them along their edges to the perimeter glue strips applied on the aforementioned lower sheet. In this way, a housing is created, in which the internal body is subsequently placed. The mattress is completed with the coupling of an upper foam rubber plate, on which further strips of glue are applied, both on the perimeter and on the surface, using the same motorized moving heads.

[0012] It is clear that this procedure is expensive in economic terms, because it requires personnel in the mattress manufacturing process. This means that it is possible to create a very small number of mattresses per minute.

[0013] Purpose of the invention

[0014] In light of the above, it is therefore the purpose of the present invention to propose a machine that allows the production of mattresses in an automated way, without the intervention of operators.

[0015] Another purpose of the invention is to allow a speedy continuous production of mattresses.

[0016] A further purpose of the present invention is to provide the tools necessary for carrying out the method and the apparatus, which carry out this method.

[0017] Object of the invention

[0018] It is specific object of the present invention a machine for the production of mattresses, comprising movement means, for moving an internal body according to an advancement direction, characterized in that it comprises at least one coating unit, in its turn comprising at least one unwinding unit, for applying a coating on at least one respective surface of said internal body, while said internal body is moved by means of said movement means.

[0019] Always according to the invention, said machine may comprise unwinding units for coating the lateral surface of said internal body, wherein each of said unwinding units comprises coating supply means for coating said respective lateral surface to be coated with said internal body, application members, such as rollers and the like, for applying said coating to said lateral surface to be coated of said internal body.

[0020] Still according to the invention, said coating supply means may comprise at least one coating coil for coating said respective lateral surface to be coated with said internal body.

[0021] Advantageously according to the invention, said coating unit may comprise an upper unwinding unit, for coating the upper surface of said internal body to be coated; and a lower unwinding unit, to coat the lower surface of said internal body to be coated.

[0022] Preferably according to the invention, said upper unwinding unit and / or said lower unwinding unit, may comprise at least one head for applying glue, having one or more nozzles for spraying glue on the face of the coating to be applied and glued to said respective lateral surface to be coated of said internal body.

[0023] Always according to the invention, said coating unit may comprise: a first lateral unwinding unit, for coating a first lateral surface of said internal body to be coated; and a second lateral unwinding unit, to coat the second lateral surface, opposite to said first lateral surface, of said internal body to be coated.

[0024] Still according to the invention, said first lateral unwinding unit and / or said second lateral unwinding unit, may comprise at least one head for applying glue, having one or more nozzles for spraying glue on the face of the coating to be applied and glued to said respective lateral surface to be coated of said internal body.

[0025] Advantageously according to the invention, said coating unit may comprise a head unwinding unit, for applying a coating layer between a first and a second internal body fed consecutively by said movement means.

[0026] Further according to the invention, said head unwinding unit may comprise a coil of coating, a cutting device, able to cut said coating to size, to such an extent as to allow the coating of the front and / or rear surfaces of said internal body, and wherein said head unwinding unit is configured to apply a covering layer on the front surface and on the rear surface of two consecutive internal bodies moved by means of said movement means.

[0027] Preferably according to the invention, said machine may comprise a gluing unit, for applying glue on the opposite main surfaces of the covering.

[0028] Always according to the invention, said gluing unit may comprise a first and a second head for applying glue, wherein each head for applying glue comprises three nozzles for spraying glue on the opposing main surfaces of the coating.

[0029] Still according to the invention, said head unwinding unit may be arranged upstream or downstream of said unwinding units for the coating of the side surface of said internal body of said coating unit.

[0030] Advantageously according to the invention, said machine may comprise a cross cutting unit, whose cutting line is perpendicular to said advancement direction, wherein said cross cutting unit is configured to transversely cut each of the coating layers, which couples two consecutive internal bodies. Always according to the invention, said machine may comprise one or two longitudinal-lateral cutting units, arranged on a respective side of said movement means, downstream of said unit coating, wherein said one or two longitudinal-lateral cutting units are suitable for laterally cutting any excess material of said mattress.

[0031] Furthermore, according to the invention, the mattress to be coated may comprise springs, and the machine may comprise a compression unit for arranging tie rods to hold the springs of the coated mattress compressed.

[0032] Further according to the invention, said compression unit may comprise a support base, a bridge fixed to said support base, arranged so as to overlie said covered mattresses while they are moved along said advancement direction, and a stitching head, movable on said bridge, to insert and sew said tie rods into said covered mattresses, as they pass under said bridge.

[0033] Advantageously according to the invention, said coating made of foam rubber plates.

[0034] It is therefore object of the present invention, a method for coating an internal body, by means of a machine for the production of mattresses according to any one of the preceding claims, comprising the following steps: A. advancing an internal body by means of said movement means; and B. coating at least one surface of said internal body by means of an unwinding unit of said coating unit.

[0035] Always according to the invention, said step B may comprise the following sub-steps: B1. coating the upper surface of said internal body with said upper unwinding assembly; B2. coating the lower surface of said internal body with said lower unwinding assembly; B3. coating the first lateral surface of said internal body by means of said right side unwinding unit; and B4. coating the second lateral surface of said internal body by means of said left side unwinding unit.

[0036] Still according to the invention, said method may comprise the following step: D. applying one layer of coating between a first and a second internal body fed consecutively by said movement means.

[0037] Advantageously according to the invention, said step D may comprise the following sub-steps: D1 . cutting a covering plate having the size of the front surface or of the rear surface of said internal body; D2. applying a layer of glue to the surfaces opposite said facing plate; D3. coupling two consecutive internal bodies, so as to coat the front surface and the rear surface respectively; and said method may comprise the following further step: E. cutting transversally with respect to said advancement direction said covering plate which couples said two consecutive internal bodies.

[0038] Brief description of the figures

[0039] The present invention will be now described, for illustrative but not limitative purposes, according to its preferred embodiments, with particular reference to the figures of the enclosed drawings, wherein: figure 1 shows a schematic side view of a first embodiment of a machine for the production of mattresses, according to the present invention; figure 2 shows a schematic view from top of the mattress production machine of figure 1 ; figure 3 shows an internal body; figure 4 is a side schematic view of a second embodiment of a machine for the production of mattresses, according to the present invention; figure 5 shows a schematic view from above of the mattress production machine of figure 4; and figures 6A-6F show some operational method steps of the mattress production machine according to figure 1.

[0040] Detailed description

[0041] In the various figures, similar parts will be indicated with the same numerical references.

[0042] Referring to the attached figures 1 and 2, it is observed a machine for the production of mattresses according to the present invention, wholly indicated with the numerical reference 1 .

[0043] The machine 1 for the production of mattresses 6 generally comprises movement means 2, to allow movement in an advancement direction indicated with the arrow A of the internal bodies 3 to be covered, a coating unit 4, which comprises, with reference to the embodiment shown, four unwinding units, indicated with the numerical references 41 , 42, 43, and 44, and a further head unwinding unit 45. Said unwinding units are each suitable for unwinding a respective foam rubber coil for the realization of the containment casing of a respective internal body 3, so as to allow the creation of a finished mattress 6.

[0044] The machine 1 for the production of mattresses 6 also comprises a transversal cutting unit 6, the operation of which will be better explained below.

[0045] With reference to figure 3, the perspective view of an internal body 3 is observed, which, as can be seen, has an upper surface 31 , a lower surface 32, opposite to said upper surface 31 , a right lateral surface, or first lateral surface 33, a left lateral surface, i.e. second lateral surface 34, opposite to said first lateral surface 33, a front surface 35 and a rear surface 36, opposite to said front surface 35. In particular, it is intended that the front surface is that which advances in the advancement direction A (which is aligned with the X axis of the Cartesian plane shown in the figures). The encapsulated spring body 3 is formed, as mentioned, by a plurality of pocket springs 37, also known as “spring boxes”, matrix arranged. In other embodiments, the internal body can be entirely made of foam, with LFK springs, Bonnell type or continuous wire springs.

[0046] In some cases, insulating layers such as wool, felt and the like are placed over the upper surface 31 and lower surface 32, before covering with foam rubber. In the following, coating plate and coating will be used interchangeably.

[0047] The movement means 2 comprise a motorized table 21 , typically a table with motorized rollers (the rollers are not shown in the figure), to allow the continuous movement of internal bodies 3 in the advancement direction A. In particular, as can be seen in the figure, the internal bodies 3 are fed in said advancement direction A one after the other, separately.

[0048] The movement means 2 also comprises upper sliding and pressing guide members 22, typically comprising a plurality of rollers, and lateral pressing sliding guide members 23, also in this case, generally comprising a plurality of rollers. Said upper sliding and pressing guide members 22 and said lateral pressing sliding guide members 23 are configured to keep each internal body 3 to be coated in position during the machining steps.

[0049] The coating unit 4, as mentioned, includes five unwinding units, namely:

[0050] - an upper unwinding unit 41 , intended to cover the upper surface 31 of the internal body 3 to be coated;

[0051] - a lower unwinding unit 42, intended to cover the lower surface 32 of the internal body 3 to be covered;

[0052] - a first lateral unwinding unit 43, intended to cover the first lateral surface 33 of the internal body 3 to be covered;

[0053] - a second lateral unwinding unit 44, intended to cover the second lateral surface 34 31 of the internal body 3 to be covered; and

[0054] - a head unwinding unit 45, intended to cover the front 35 and rear 36 surfaces, as better indicated below.

[0055] For simplicity, the upper unwinding unit 41 and the head unwinding unit 45 are described in detail. From a structural point of view, each of the other lower 42, first 43, and second 44 lateral unwinding units have the same structure as the upper unwinding unit 41 , although it is intended to cover a different surface of the internal body 3, as mentioned above.

[0056] The upper unwinding unit 41 comprises a coil 411 of covering plate 412, which, in the present embodiment, is foam rubber, for covering the upper surface 31 of an internal body 3, and applicator members, such as one or more rollers 413, for the application of the foam rubber plate 412 to said upper surface 31 of the internal body 3.

[0057] In other embodiments, different coating materials may be used.

[0058] Furthermore, the upper unwinding unit 41 also comprises a head for applying glue 414, having one or more nozzles for spraying glue on the face of the foam rubber sheet 412 to be applied and glued to the upper surface 31 of the internal body 3. The head for the application of glue 414 is in particular configured to apply a layer of glue at the perimeter of the surface of the foam rubber plate 414, as well as some strips on the internal portion of the surface itself.

[0059] Similarly, the lower unwinding unit 42 comprises a coil 412 of foam rubber sheet 422, two rollers 423, as coating 421 applicator members, and a glue application head 414 with two nozzles for spraying glue. In this case, the foam rubber plate 422 is coupled to the lower surface 32 of the encapsulated spring 3.

[0060] The first lateral unwinding unit 43 comprises a coil 432 of foam plate 432, a roller 433 and a glue application head 434 with two nozzles for spraying glue. In this case, the foam rubber plate 432 is coupled to the right lateral surface 33 of the encapsulated springing 3. Furthermore, said nozzles are configured to apply glue on the surface of the foam rubber plate 432, which comes into contact with the internal body 3 and / or on the edge surfaces that come into contact with the upper 414 and lower 424 foam rubber plates.

[0061] In some embodiments, the first lateral unwinding unit 43 may not include the glue application head 434, as the foam rubber sheet 432 would be coupled, for example, to the upper 412 and lower 422 foam rubber sheets.

[0062] The second lateral unwinding unit 44 comprises a coil 442 of foam sheet 442, a pulley 443 and a glue application head 444 with two nozzles for spraying glue. In this case, the foam rubber sheet 442 is coupled to the left lateral surface 34 of the encapsulated spring 3. Also, in this case, said nozzles are configured to apply glue on the surface of the foam rubber sheet 432, which comes into contact with the internal body 3 and / or on the edge surfaces that come into contact with the upper 414 and lower 424 foam rubber plates.

[0063] Also in this case, in some embodiments, the second lateral unwinding unit 44 may not include the head for applying glue 444, as the foam rubber sheet 442 would be coupled, for example, to the upper foam rubber sheets 412 and lower 422.

[0064] The unwinding units 41 , 42, 43, and 44 operate continuously and simultaneously, to allow the application of the foam rubber sheet of the respective coil, allowing the coating of the indicated surfaces of the internal body 3 at the same time.

[0065] The head unwinding unit 45 comprises, similarly to the other unwinding units, a coil 451 of foam rubber sheet 452. The head unwinding unit 45 also comprises a cutting device 453, suitable for cutting to size, as will be better explained below, of the longitudinal portions of foam rubber sheet 452, always covering, according to a size such as to allow the covering of the front 35 or rear 36 surfaces of the internal bodies 3 to be covered.

[0066] The head unwinding unit 45 also comprises a gluing unit 454, comprising a first 4541 and a second 4542 head for applying glue. Each 4541 and 4542 glue application head comprises three nozzles for spraying glue onto both opposing main surfaces of the 452 foam plate.

[0067] In some embodiments, the head unwinding unit 45 may not comprise the gluing unit 454, as the foam rubber sheet 442 would be coupled, for example, to the upper 412 and lower 422 foam rubber plates.

[0068] As can be seen, the head unwinding unit 45 is arranged upstream with respect to the other unwinding units of the coating unit 4, and it is configured to allow the application of a foam rubber unit 452 between two consecutive internal bodies 3. In particular, each foam rubber unit 452 is glued to the front surface 35 of the arriving internal body 3 and to the rear surface 36 of the internal body 3 that has just passed. The internal bodies 3, as mentioned, are powered by the motorized table 21 , as will be better explained below.

[0069] In some embodiments, the unwinding units 41 , 42, 43, 44, and 45 may not even provide coils, but in general means for feeding the coating plates, for the continuous feeding of the coating plates for the coating of the internal body 3.

[0070] As mentioned, the machine 1 for the production of mattresses 4 also comprises a transverse cutting unit (or cutter) 5, arranged downstream of the coating unit 4, whose cutting line 51 is perpendicular to advancement direction A. The operation of the transversal cutting unit 5 will be better explained below.

[0071] In any case, in other embodiments, said transversal cutting unit 5 can be arranged upstream of the coating unit 4, as long as it is downstream of the head unwinding unit 45.

[0072] In some embodiments, the machine 1 for the production of mattresses 4 also comprises two longitudinal-lateral cutting units (or cutters) 101 and 102, arranged on the sides of the motorized table 21 and therefore of the mattresses 6, downstream of the unit of covering 4, designed to laterally cut any excess material, to bring the mattress 6 to size. The cutting lines of said two longitudinal-lateral cutting units 101 and 102 are parallel and oriented according to the X-axis of the Cartesian plane shown in figure 1 .

[0073] The operation of the machine 1 for the production of mattresses 6 described above is as follows.

[0074] As can always be seen in the figures, when an internal body 3 is inserted into the machine 1 , at the same time the head unwinding unit 45 unrolls the foam rubber plate 452 from the coil 451 , which is treated, in the machine 1 according to the embodiment at issue, by means of glue on two opposite sides using the gluing unit 54. In particular, the application of glue takes place via the first 4541 and the second 4542 glue application heads. As mentioned, the size of the foam rubber sheet 452 to be applied is such as to cover the front surface 35 and the rear surface 36 (which are the same) of the internal body 3.

[0075] The cut piece of foam rubber plate 452 is applied, as shown in the figure, to the front surface 35 of the arriving inner body 3', and to the tail surface 36 of the next 3' inner body, which is introduced into the machine 1 .

[0076] Consequently, the internal bodies 3, which arrive separated, are coupled together by means of the foam rubber plates 452, coated with glue and suitably cut by the head unwinding unit 45 according to a continuous process.

[0077] As mentioned, subsequently, the series of internal bodies 3 are coupled together by means of the foam rubber plates 452, are introduced into the machine 1 and arranged in position by means of the upper guide members 22 and the lateral guide members 23.

[0078] Subsequently, the coating unit 4 covers the upper 31 and lower 32 surfaces, and the first 33 and second 34 lateral surfaces, using the different four unwinding units. This operation is also carried out according to a continuous process. In particular, again by way of example, considering the operation of the upper unwinding unit 41 , the foam rubber coil 411 is continuously unwound according to the direction indicated in arrow B, and the foam rubber plate 412 is applied on the upper surface 31 of the internal body 3, passing through one of the rollers 413, after a layer of glue is applied to one of the surfaces by the glue application head 414.

[0079] Similarly, the foam rubber plates are applied, as mentioned, on the lower surface 36, and on the first 33 and second 34 lateral surfaces of the encapsulated spring body 3.

[0080] Downstream the coating unit 4, the internal body 3 is covered on the lateral surfaces 31 , 32, 33, and 34, but also, by means of the foam rubber plates 52, on the front 35 and rear surfaces 36. To separate the several mattresses 6 made, at this point while the different internal bodies 3 now covered always advance according to the advancement direction A, the transversal cutting unit 5 sections along the cutting line 51 transversally each of the foam rubber plates 52, which couples two interior bodies 3, thus leaving a layer of foam rubber covering the front face 35 of the previous mattress 6 and a layer of foam rubber covering the rear face 36 of the subsequent mattress 6.

[0081] Since the foam rubber plates 52 are cut transversally in half, their thickness is greater, preferably double, than the other foam rubber plates that cover the internal body 3.

[0082] In this way, a complete mattress 6 is obtained, which comprises an internal body 3, covered with a foam rubber containment casing glued to it.

[0083] In general, the glue can be of different types, and in particular, by way of example, the glues sprayed by the glue application heads can be vinyl, water-based, hot-melt, vinavil®, and the like.

[0084] The glues can be applied not only by spraying, as in the embodiment described, but also by spreading and by laminating.

[0085] When one of the coils 411 , 421 , 431 , 441 or 451 ends, it is replaced with a new foam rubber coil, and the initial end of the latter is coupled by glue with the initial end of the new coil. In this way, an optimization of consumables is achieved. The two longitudinal-lateral cutting units 101 and 102 then cut any lateral excess material, so as to bring the mattress 6 to size.

[0086] Referring to figures 4 and 5, a further embodiment of the machine 1 for the production of mattresses 6 is observed, which, from a functional point of view, is completely similar to the machine 1 according to the previous embodiment, but in addition provides downstream a compression unit 7, capable of fixing tie rods to hold the springs of the covered mattress 6 in compression in one or more points of the mattress 6 itself.

[0087] In particular, said compression unit 7 is arranged downstream of said transversal cutting unit 5. Said compression unit 7 comprises a support base 71 , for the support of a bridge 72, arranged to overlay the mattresses 6 while they are moved along the advancement direction A, and a stitching head 73, coupled to said bridge 42, and movable on it, to insert and sew the tie rods into the covered mattress 6, as it passes under said bridge 72.

[0088] The coils 411 , 421 , 431 , and 441 , made of foam rubber or other covering material, may already be available on the market, or they can also be “built”. In particular, referring to figures 6A-6F, the steps for producing a coil are observed, for example coil 411 , starting from a set or stack of foam rubber sheets 9 cut to size.

[0089] In particular, observing the above figures in sequence, it can be seen how glue is placed on the end 4111 (figure 6A) via a nozzle 8 and a plate is subsequently coupled (figures 6B and 6C). Subsequently, as can be seen in figure 6D, the coil 411 is wound according to the arrow R, so that, referring to figure 6E, the nozzle 8 can apply the glue again to the new free end 4111 of the coil 411 , to allow the application of a new plate taken from the pile of foam rubber plates 9 (figure 6F).

[0090] The machine operates according to an operation method comprising the following steps:

[0091] A. advancing an internal body 3 by means of said movement means 2;

[0092] B. coating at least one surface 31 , 32, 33, 34, 35, 36 of said internal body 3 by means of one of said unwinding units 41 , 42, 43, 44, 45 of said coating unit 4. This coating step B also includes the step of:

[0093] B1. covering the upper surface 31 of said internal body 3 using said upper unwinding unit 41 ;

[0094] B2. covering the lower surface 32 of said internal body 3 using said lower unwinding unit 42; B3. covering the right lateral surface 33 of said internal body 3 using said right lateral unwinding unit 43; and

[0095] B4. cover the left lateral surface 34 of said internal body 3 using said left lateral unwinding unit 44.

[0096] Furthermore, the operating method also comprises step D of applying a foam rubber plate 452 (or covering layer) between a first and a second internal body 3, fed consecutively by said movement means 2.

[0097] Said application step D comprises the step D1 of cutting a covering plate 452 having the size of the front surface 35 or the rear surface 36 of the internal body. Furthermore, step D2 involves applying a layer of glue on the surfaces opposite to said foam rubber plate 452, and step D3 coupling two consecutive internal bodies 3, so as to cover the front surface 35 and the rear surface 36 respectively.

[0098] Finally, said method comprises the step E of cutting transversally with respect to said advancement direction A said foam rubber sheet 452, which couples said two consecutive internal bodies 3.

[0099] Advantages

[0100] An advantage of the present invention is that it allows continuous automation of the covering of internal bodies, without any operator intervention, except for the replacement of any foam rubber coils.

[0101] A further advantage of the present invention is that it allows the creation of high precision mattresses, due to to the high degree of mechanization of the system.

[0102] The present invention has been described for illustrative but not limitative purposes, according to its preferred embodiments, but it is to be understood that modifications and / or changes can be introduced by those skilled in the art without departing from the relevant scope as defined in the enclosed claims.

Claims

CLAIMS1 . Machine (1 ) for the production of mattresses (7), comprising movement means (2), for moving an internal body (3) according to an advancement direction (A), characterized in that it comprises at least one coating unit (4), in its turn comprising at least one unwinding unit (41 , 42, 43, 44, 45), for applying a coating (412, 422, 432, 442, 452) on at least one respective surface (31 , 32, 33, 34, 35, 36) of said internal body (3), while said internal body (3) is moved by means of said movement means (2).

2. Machine (1 ) according to claim 1 , characterized in that it comprises unwinding units (41 , 42, 43, 44) for coating the lateral surface of said internal body (3), wherein each of said unwinding units (41 , 42, 43, 44) comprises coating supply means (412, 422, 423, 424, 452) for coating said respective lateral surface (31 , 32, 33, 34) to be coated with said internal body (3), application members (413, 423, 433, 434), such as rollers and the like, for applying said coating (412, 422, 432, 442) to said lateral surface (31 , 32, 33, 34) to be coated of said internal body (3).

3. Machine (1 ) according to the preceding claim, characterized in that said coating supply means comprise at least one coating coil (411 , 421 , 431 , 441 , 412, 422, 432, 442) for coating said respective lateral surface (31 , 32, 33, 34) to be coated with said internal body (3).

4. Machine (1 ) according to any one of the preceding claims, characterized in that said coating unit (4) comprises an upper unwinding unit (41 ), for coating the upper surface (31 ) of said internal body (3) to be coated; and a lower unwinding unit (42), to coat the lower surface (32) of said internal body (3) to be coated.

5. Machine (1 ) according to the preceding claim, characterized in that said upper unwinding unit (41 ) and / or said lower unwinding unit (42), comprises at least one head for applying glue (414, 424), having one or more nozzles for spraying glue on the face of the coating (412, 422) to be applied and glued to said respective lateral surface (31 , 32) to be coated of said internal body (3).

6. Machine (1 ) according to any one of the preceding claims, characterized in that said coating unit (4) comprises: a first lateral unwinding unit (43), for coating a first lateral surface (33) of said internal body (3) to be coated; and a second lateral unwinding unit (44), to coat the second lateral surface (34), opposite to said first lateral surface, of said internal body (3) to be coated.

7. Machine (1 ) according to the preceding claim, characterized in that said first lateral unwinding unit (43) and / or said second lateral unwinding unit (44), comprises at least one head for applying glue (434, 444), having one or more nozzles for spraying glue on the face of the coating (432, 442) to be applied and glued to said respective lateral surface (33, 34) to be coated of said internal body (3).

8. Machine (1 ) according to any one of the preceding claims, characterized in that said coating unit (4) comprises a head unwinding unit (45), for applying a coating layer (452) between a first and a second internal body (3) fed consecutively by said movement means (2).

9. Machine (1 ) according to the preceding claim, characterized in that said head unwinding unit (45) comprises a coil (451 ) of coating (452), a cutting device (453), able to cut said coating (452) to size, to such an extent as to allow the coating of the front (35) and / or rear (36) surfaces of said internal body (3), and wherein said head unwinding unit (45) is configured to apply a covering layer (452) on the front surface (35) and on the rear surface (36) of two consecutive internal bodies (3) moved by means of said movement means (2).

10. Machine (1 ) according to the preceding claim, characterized in that it comprises a gluing unit (454), for applying glue on the opposite main surfaces of the covering (452).

11. Machine (1 ) according to the preceding claim, characterized in that said gluing unit (454) comprises a first (4541 ) and a second (4542) head for applying glue, wherein each head for applying glue (4541 , 4542) comprises three nozzles for spraying glue on the opposing main surfaces of the coating (452).

12. Machine (1 ) according to any one of claims 8-11 , characterized in that said head unwinding unit (45) is arranged upstream or downstream of said unwinding units (41 , 42, 43, 44) for the coating of the side surface of said internal body (3) of said coating unit (4).

13. Machine (1 ) according to any one of claims 8-12, characterized in that it comprises a cross cutting unit (5), whose cutting line (51 ) is perpendicular to said advancement direction (A), wherein said cross cutting unit (5) is configured to transversely cut each of the coating layers (452), which couples two consecutive internal bodies (3).

14. Machine (1 ) according to any one of the preceding claims, characterized in that it comprises one or two longitudinal-lateral cutting units (101 , 102), arranged on a respective side of said movement means (2), downstream of said unit coating (4), wherein said one or two longitudinal-lateral cutting units (101 , 102) are suitable for laterally cutting any excess material of said mattress (6).

15. Machine (1 ) according to any one of the preceding claims, wherein the said mattress to be coated comprises springs, characterized in that it comprises a compression unit (7) for arranging tie rods to hold in compression the springs of the covered mattress (6).

16. Machine (1 ) according to the preceding claim, characterized in that said compression unit (7) comprises a support base (71 ), a bridge (72) fixed to said support base (71 ), arranged so as to overlie said covered mattresses (6) while they are moved along said advancement direction (A), and a stitching head (73), movable on said bridge (72), to insert and sew said tie rods into said covered mattresses (6), as they pass under said bridge (72).

17. Machine (1 ) according to any one of the preceding claims, characterized in that said covering (412, 422, 432, 442, 452) is made of foam rubber.

18. Method for coating an internal body (3), by means of a machine (1 ) for the production of mattresses (7) according to any one of the preceding claims, comprising the following steps:A. advancing an internal body (3) by means of said movement means (2); andB. coating at least one surface (31 , 32, 33, 34, 35, 36) of said internal body (3) by means of an unwinding unit (41 , 42, 43, 44, 45) of said coating unit (4).

19. Method according to the preceding claim, when dependent on claims 4 and 6, characterized in that said step B comprises the following sub-steps:B1. coating the upper surface (31 ) of said internal body (3) with said upper unwinding assembly (41 );B2. coating the lower surface (32) of said internal body (3) with said lower unwinding assembly (42);B3. coating the first lateral surface (33) of said internal body (3) by means of said right side unwinding unit (43); andB4. coating the second lateral surface (34) of said internal body (3) by means of said left side unwinding unit (44).

20. Method according to any one of claims 18 or 19, when dependent on any one of claims 8-12, characterized in that it comprises the following step:D. applying one layer of coating (452) between a first and a second internalbody (3) fed consecutively by said movement means (2).

21. Method according to any one of claims 18-20, when dependent on claim 13, characterized in that said step D comprises the following sub-steps:D1 . cutting a covering plate (452) having the size of the front surface (35) or of the rear surface (36) of said internal body (3);D2. applying a layer of glue to the surfaces opposite said facing plate (452); D3. coupling two consecutive internal bodies (3), so as to coat the front surface (35) and the rear surface (36) respectively; and in that said method comprises the following further step:E. cutting transversally with respect to said advancement direction (A) said covering plate (452) which couples said two consecutive internal bodies (3).

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