Rolling element support group and rotating table provided with such support group

Abstract

A support group (1) is disclosed that is suitable for rotatingly supporting a rotatable resting plate (101) of a rotating table (100) for a wrapping apparatus, the support group (1) being provided with: - a base (2); and with - a plurality of rolling elements (3). The rolling elements (3) are configured to be fitted to the base (2) and to support a lower surface (103) of the resting plate (101) rotating around a vertical axis (Y) of rotation. Each rolling element (3) is freely rotatable around a respective longitudinal axis of rotation (L). Each rolling element (3) has an outer frustoconical contact surface (4) and the longitudinal axis of rotation (L) of each rolling element (3) is arranged on a respective vertical plane passing through the vertical axis (Y) of rotation and is tilted with respect to the lower surface (103) of the resting plate (101) so that the outer frustoconical contact surface (4) abuts on the lower surface (103), so that the peripheral speed of each zone of the outer frustoconical contact surface (4) is equal to the peripheral speed of a respective portion of lower surface (103) that rests on this zone.

Description

Background of the invention

[0001] The invention relates to a rolling element support group in particular intended to rotatingly support a rotating table, such as a rotating table of a wrapping apparatus for wrapping loads to be palletized.

[0002] The invention also relates to a rotating table provided with such support group.

[0003] Rolling element support groups for a rotating table are known from the prior art in which each of the rolling elements is fitted to a respective seat of a base so as to be able to rotatingly support a rotating plate of the rotating table that rotates around a vertical rotation axis (wrapping axis) in order to be able to wrap a load arranged in use thereupon with a film by means of a wrapping apparatus.

[0004] Each of such prior art rolling elements has a cylindrical shape and is so fitted to the base that a respective longitudinal axis of rotation thereof is arranged radially and perpendicularly to the vertical rotation axis and an outer side surface contacts a lower surface of the rotating plate. During the rotation of the rotating plate around the vertical rotation axis, each rolling element is free to rotate around the respective longitudinal axis of rotation and consecutive portions of the outer side surface of each rolling element contact corresponding consecutive portions of the lower surface of the rotating plate.

[0005] One examples of a rotating table provided with rolling elements di cylindrical shape is known from US2010 / 064906 A.

[0006] In the rolling element support groups for a rotating table that are known from the prior art, the peripheral speed of the rolling element is the same along the entire cylindrical outer side surface thereof, whereas the peripheral speed of the zones - of the rotating plate - in contact with the rolling element varies according to the distance of each zone from the axis of rotation of the rotating plate. In particular, the value of the peripheral speed of the rotating plate measured at the end of the cylindrical rolling element nearer the vertical rotation axis is below the value of the peripheral speed of the rotating plate measured near the further end of the cylindrical rolling element further from the vertical rotation axis.

[0007] The non-uniformity of the peripheral speed of the rotating plate with respect to the peripheral speed of the outer surface of the cylindrical rolling element in contact therewith and thus the peripheral speed difference between the zones that are in reciprocal contact of the rotating plate and of the rolling element generates sliding and friction between the rolling element and rotating plate that entail rapid deterioration of the rolling element. It is accordingly necessary to replace the rolling element because of wear to a part of the rolling element.

[0008] This causes high maintenance and material replacement costs.

[0009] Further, when the rolling elements have to be replaced, the rotating table provided with a prior art rolling element support group cannot be used, thus causing disadvantageous machine downtime. The time for replacing the rolling elements that have to be replaced because of wear thus significantly lower the productivity of known wrapping apparatuses that use this rotating table to wrap a load with a film.

[0010] There is thus ample room for improvement in the prior art.Summary of the invention

[0011] One object of the invention is to improve the prior-art rolling element support groups intended to support a rotating table.

[0012] Another object of the invention is thus to improve rotating tables of known type.

[0013] A further object is to make a rolling element support group for a rotating table that enables the productivity to be considerably increased of a wrapping apparatus with which the rolling element support group according to the invention is associated compared with wrapping apparatuses with known rolling element support groups.

[0014] Still another object is to obtain a rolling element support group that is simple and easily installable in an already known rotating table of rotating load wrapping apparatuses.

[0015] The objects of the invention, and still others are achieved with a rolling element support group and with a rotating table with such a support group according to what is defined in the appended claims.

[0016] In one embodiment, a support group suitable for rotatingly supporting a rotatable resting plate of a rotating table for a wrapping apparatus is provided with: a base; and with a plurality of rolling elements, the rolling elements being configured to be fitted to the base and to support a lower surface of the resting plate rotating around a vertical axis of rotation; each rolling element is freely rotatable around a respective longitudinal axis of rotation. Each rolling element has an outer frustoconical contact surface and the longitudinal axis of rotation di each rolling element is arranged on a respective vertical plane passing through the vertical axis of rotation and is tilted with respect to the lower surface of the resting plate so that the outer contact surface abuts on the lower surface, so that the peripheral speed of each zone of said outer frustoconical contact surface is equal to the peripheral speed of a respective portion of the lower surface that rests on this zone.

[0017] Owing to the rolling element support group for a rotating table according to the invention that comprises rolling elements of frustoconical rather than cylindrical shape like the shape of the rolling elements of the prior art support groups, on each zone of the outer side surface of each rolling element (that is the surface designed to contact a lower surface of a resting plate for the load) a peripheral speed is measurable that is equal to the peripheral speed of a respective portion of lower surface of the resting plate that rests on this zone, independently of the radial position of the rolling element with respect to the vertical axis of rotation of the resting plate.

[0018] This prevents the rolling elements from being subjected to corresponding sliding and / or friction with respect to the resting plate, which would cause wear to the rolling elements and as a result replacement of the damaged rolling elements.

[0019] The working life of the rolling element support group is thus significantly increased.

[0020] This also enables the productivity of the rotating load wrapping apparatuses that use a rotating table according to the invention to be increased significantly with respect to known wrapping apparatuses, because machine downtime for operations of replacing the rolling elements is significantly reduced.

[0021] Lastly, the rolling element support group according to the invention has the advantage of being constructionally simple and easily installable in already known rotating load wrapping apparatuses.

[0022] These above advantages are accordingly detectable in a rotating table equipped with a rolling element support group according to the invention and in a wrapping apparatus comprising a rotating table provided with a rolling element support group according to the invention.Short description of the drawings

[0023] The invention can be better understood and implemented with reference to the appended drawings, which illustrate an embodiment thereof by way of non-limiting example, in which: Figure 1 is a top plan view of a rotating table provided with a rolling element support group according to the invention; Figure 2 is a side view of the rotating table of Figure 1; Figure 3 is a top plan view of a rolling element support group according to the invention; Figure 4 is an exploded perspective view of the rotating table of Figure 1; Figure 5 is a section taken along the plan V-V of Figure 1; Figure 6 is an enlarged detail of Figure 5; Figure 7 is a perspective view of a rolling element of the support group of Figure 3 in a fitting configuration in a housing seat; Figure 8 is a perspective view of a rolling element of the support group of Figure 3 in a position spaced apart from a housing seat; Figure 9 is a side view of the rolling element of Figure 7 in a fitting configuration in a housing seat; Figure 10 is a bottom view of the rolling element of Figure 9 mounted into a housing seat; Figure 11 is a top view of the rolling element of Figure 9 fitted into a housing seat; Figure 12 is a (right) front view of the rolling element of Figure 9 mounted into a housing seat; Figure 13 is a (left) rear view of the rolling element of Figure 9 fitted into a housing seat; Figure 14 is a view like that of Figure 7 taken from another angle; Figure 15 is a view like that of Figure 8 taken from another angle; Figure 16 is a side view of a rolling element and of a respective support element in an assembled configuration; Figure 17 is a (right) front view of the rolling element and of the respective support element of Figure 16; Figure 18 is a (left) rear view of the rolling element and of the respective support element of Figure 16; Figure 19 is a perspective view of the rolling element and of the respective support element of Figure 16; Figure 20 is an exploded view of the rolling element and of the respective support element of Figure 16. Detailed description

[0024] With reference to the attached Figures, for the sake of simplicity, identical elements of similar components, unless otherwise stated, have been indicated by the same numbering.

[0025] With reference to the aforementioned Figures, a rotating table according to the invention has been indicated over all by 100 that is configured to rotate a load to be wrapped with a film.

[0026] The rotating table 100 can be associated with or be comprised in, a wrapping apparatus, in particular of the rotating load type, arranged for wrapping the film around the rotating load by the application of a certain number of wrapping coils or strips around the load.

[0027] The rotating table 100 comprises a resting plate 101 intended to receive restingly the load to be wrapped with the film. The resting plate 101 is rotatable around a vertical rotation axis Y, or wrapping axis, so that the load can be wrapped with the film by the wrapping apparatus.

[0028] The resting plate 101 is disc-shaped and comprises an upper surface 102 on which the load is restingly arranged, and a lower surface 103 opposite the upper surface 102.

[0029] Still with reference to the aforementioned Figures, a support group according to the invention configured to support rotatingly the rotatable resting plate 101 has been indicated overall by 1.

[0030] The resting plate 101, in use, is thus rotatingly supported by the support group 1.

[0031] The rotating table 100 can comprise, or be associated with, the support group 1 according to the invention.

[0032] The resting plate 101 thus acts as a support for the load and is configured to rotate the load around the vertical rotation axis Y during a wrapping cycle during which the load - when rotated by the rotatable resting plate 101 - is wrapped by the wrapping film in order to apply a set number of film wrapping coils to the load.

[0033] In other words, the support group 1 is suitable for rotatingly supporting the rotatable resting plate 101 of the rotating table 100. In particular, the support group 1 engages the lower surface 103 to rotatingly support the rotatable resting plate 101.

[0034] The resting plate 101 and the load are rotated around the vertical rotation axis Y along a wrapping direction, for example a clockwise rotation direction.

[0035] The film is, in particular, unwound from a reel.

[0036] The vertical rotation axis Y is substantially vertical, i.e. substantially parallel to the gravity acceleration vector.

[0037] The load can be arranged resting on a support that is positionable on the resting plate 101 like, for example, a pallet, i.e. can be a palletized load.

[0038] The load can consist of a product or of a plurality of products, for example, grouped on a pallet.

[0039] The film is made of an elastic material and / or plastics, for example can be an extendible film having elasticity that is such as to be able to be applied and shaped around the load and, at the same time, is such as to keep the latter together in a stable manner. Further, the film can be, in particular, a macroperforated film and / or a biodegradable film and / or a heat-sensitive film.

[0040] The support group 1 is provided with a base 2.

[0041] The base 2 can be arranged resting on a floor P or a terrain.

[0042] The support group 1 is further provided with a plurality of rolling elements 3, which rolling elements 3 are configured to be mounted to the base 2 and to support the lower surface 103 of the resting plate 101 rotating around the vertical axis Y of rotation.

[0043] The lower surface 103 is, in particular, flat and lies on a horizontal plane γ that is substantially perpendicular to the vertical axis of rotation Y.

[0044] Each rolling element 3 is freely rotatable around a respective longitudinal axis of rotation R.

[0045] Each rolling element 3 has an outer frustoconical contact surface 4. The outer frustoconical contact surface 4 of each rolling element 3 is configured to contact, in use, a respective portion of the lower surface 103.

[0046] Each rolling element 3 has a substantially frustoconical shape. In particular, each rolling element 3 has a hollow truncated shape. The outer frustoconical contact surface 4 of each rolling element 3 is the side surface of each truncated cone.

[0047] In use, in order to enable the support group 1 to support the resting plate 101 while it is rotated, the rolling elements 3 have to be able to abut on (i.e. come into contact with, adhere to) the lower surface 103 of the resting plate 101 from below. In particular, the rolling elements 3 and the lower surface 103 engage by contact in a contact zone. The extent of the contact zone, in particular along a horizontal direction that is substantially perpendicular to an apothem of the truncated cone, depends on the material with which each rolling element 3 is made, in particular near the outer frustoconical contact surface 4. For example, the contact zone can extend along an apothem of the truncated cone or can comprise a strip that comprises and extends near an apothem of the truncated cone. The outer frustoconical contact surface 4 of each rolling element 3 can be made of plastics, in particular comprising polyamide, still more in particular comprising Nylon, for example loaded with oil, in particular lubricating oil, or glass fibre. For example, the outer frustoconical contact surface 4 of each rolling element 3 can be made of PAG6 Nylon loaded with lubricating oil, or PA6 nylon loaded with glass fibre.

[0048] The rotation of the resting plate 101 around the vertical rotation axis Y results in rotation of the rolling elements 3 around the respective longitudinal axis of rotation L because of sliding friction between the lower surface 103 and the outer contact surface 4, when the resting plate 101 is rotated.

[0049] The rolling elements 3 thus each behave in use like a sort of idling supporting wheel, i.e. free to rotate around the respective axis of rotation, configured to rotatably support the rotatable resting plate 101.

[0050] The longitudinal axis of rotation L of each rolling element 3 is arranged on a respective vertical plane passing through the vertical axis Y of rotation and is tilted with respect to the lower surface 103 of the resting plate 101 so that the outer frustoconical contact surface 4 abuts on the lower surface 103 of the resting plate 101 so that the peripheral speed of each zone of the outer frustoconical contact surface 4 is equal to the peripheral speed of a respective portion of the lower surface 103 that rests on this zone.

[0051] A zone of the outer frustoconical contact surface 4 means a point or an area of the outer frustoconical contact surface 4, for example an annular sector, in which the peripheral speed of the rolling element 3 is considerably constant.

[0052] Respective portion of the lower surface 103 means a point or an area of the lower surface 103, for example an area, for example an annular sector, in the peripheral speed of the rotatable resting plate 101 is considerably constant.

[0053] The portion of the lower surface 103 is considered to be "respective" of a zone of the outer frustoconical contact surface 4 (and vice versa) because it contacts this zone, i.e. it is positioned directly above this zone along the acceleration vector of terrestrial gravity.

[0054] In other words, on each contact portion / point between the outer frustoconical contact surface 4 and the lower surface 103 the measured peripheral speed is the same owing to the truncated cone shape of each rolling element 3, to the arrangement of the longitudinal axis of rotation L of each rolling element 3 and to mounting each rolling element 3 in contact with the lower surface 103 of the resting plate 101 in the contact zone.

[0055] Owing to the fact that the peripheral speed of the resting plate 101 and of each rolling element 3 is the same along the contact zone considering corresponding zones of the lower surface 103 and of the outer frustoconical contact surface 4 (i.e. reciprocal rest areas or points, i.e. positioned one above the other along the acceleration vector of terrestrial gravity), sliding and / or friction between the resting plate 101 and parts of each rolling element 3 is avoided. In this manner, the working life of the rolling elements 3 is significantly extended compared with that of prior-art cylindrical cylinders because the absence of sliding and / or friction due to differences in peripheral speed does not entail uneven deterioration of the rolling element 3 along a direction that is radial with respect to the vertical axis of rotation Y.

[0056] Each longitudinal axis of rotation L of the respective rolling element 3 can have a tilt that is such as to be nearer the lower surface 103 of the resting plate 101 in the direction of approach to the vertical axis Y of rotation.

[0057] In other words, if one considers a direction of approach towards the vertical axis of rotation Y, each longitudinal axis of rotation L progressively approaches the lower surface 103 of the resting plate 101.

[0058] Each longitudinal axis of rotation L of the respective rolling element 3 is tilted with respect to the horizontal plane γ on which the lower surface 103 rests by an angle of tilt α comprised between 2° and 4°, in particular by an angle of tilt equal to 3°.

[0059] Each longitudinal axis of rotation L of the respective rolling element 3 is, in other words, transverse to the horizontal plane γ on which the lower surface 103 of the rotatable resting plate 101 lies.

[0060] Each longitudinal axis of rotation L of the respective rolling element 3 projects substantially radially from the vertical axis of rotation Y.

[0061] The vertical axis of rotation Y can be a central axis of the base 2.

[0062] The formulas will be supplied below that are used to determine a value of the lesser radius r2 of the truncated cone of each rolling element 3 (from which it is possible to calculate the angle of conicity of the truncated cone, i.e. the angle between the longitudinal axis of rotation L of each rolling element 3 and the apothem of the truncated cone of each rolling element 3) so that, in the respective points of contact between each rolling element 3 and the rotatable resting plate 101 the outer frustoconical contact surface 4 of each rolling element 3 has the same peripheral speed even when the radial position of the point of contact decreases with respect to the vertical axis of rotation Y.

[0063] The lesser radius r2 is the radius of the lesser base of the truncated cone. If the truncated cone is chamfered and does not have corners on the lesser base, the lesser base is considered to be an area of the rolling element 3 comprised in a circle of a section taken on a plane that is perpendicular to the longitudinal axis of rotation L extending nearer the vertical axis of rotation Y and which abuts on the lower surface 103.

[0064] The data from which it is possible to calculate the lesser radius r2 are: a value of the rotation speed n of the resting plate 101; for example n can be equal to 10 RPM; a value of the greater radius r1 of the truncated cone; for example, r1 can be equal to 26.5 mm; the greater radius r1 is the radius of the greater base of the truncated cone; if the truncated cone is chamfered and does not have corners on the greater base, an area of the rolling element 3 comprised in a circle of a section taken on a plane that is perpendicular to the longitudinal axis of rotation L extending further from the vertical axis of rotation Y and which abuts on the lower surface 103 is considered to be the greater base; a value of a greater radius R1 of the resting plate 101 in the point of contact p1 of the outer frustoconical contact surface 4 of a rolling element 3 with the lower surface 103 at a greater distance from the vertical rotation axis Y; for example, R1 can be equal to 750 mm; a value of a lesser radius R2 of the resting plate 101 in the point of contact p2 of the outer frustoconical contact surface 4 of a rolling element 3 with the lower surface 103 at a lesser distance from the vertical rotation axis Y; for example, R2 can be equal to 716 mm.

[0065] The peripheral speed Vp1 in the point of contact p1 resting plate 101-rolling element 3 at a greater distance from the vertical rotation axis Y is given by: Vp 1 = w × R 1 where w is the angular speed of the resting plate 101 that is given by w = 2 πn 60 whereas the peripheral speed Vp2 in the point of contact p2 resting plate 101-rolling element 3 at a lesser distance from the vertical rotation axis Y is given by: Vp 2 = w × R 2

[0066] The angular speed of each rolling element 3, each rolling element 3 being a stiff body, is the same along an approach direction to the vertical axis of rotation Y whereas the peripheral speed varies. By making the peripheral speed of a rolling element 3 in the point of contact p1 the same as that of the resting plate 101 (i.e. Vp1 ) in the same point and the peripheral speed in the point of contact p2 of a rolling element 3 the same as that of the resting plate 101 (i.e. Vp2 ) in the same point, the lesser radius r2 of the rolling element can be obtained by the following steps: Z = Vp 1 r 1 where Z is the angular speed of the rolling element 3 and Vp 2 = Z × r 2 = Vp 1 r 1 × r 2 from which we obtain r 2 = Vp 2 Vp 1 × r 1 = 2 πn 60 R 2 × 60 2 πnR 1 × r 1 i.e. r 2 = R 2 R 1 r 1

[0067] Thus by choosing each lesser radius r2 of the truncated cone of the rolling elements 3 with a value obtained from the above equation (known R1, R2 and r1) a peripheral speed of the rolling element 3 is maintained along the contact zone with the resting plate 101 corresponding to that of the resting plate 101 considering respective areas 3 (or points) of contact of the outer frustoconical surface 4 with the lower surface 103.

[0068] For example, if r1 = 26.5 mm, R1 = 750 mm and R2 = 716 mm, r2 must be chosen equal to 50 mm.

[0069] In the same way, by varying the greater radius r1 and the length of the tapered part of contact of the wheel (i.e. R1-R2) and repeating the above calculations the conicity that results therefrom will always have the same effects in any position of the table.

[0070] The plurality of rolling elements 3 can comprise at least four rolling elements 3 arranged angularly spaced from each other, in particular angularly equidistant from each other.

[0071] The plurality of rolling elements 3 can comprise two rolling elements 3 having respective longitudinal axis of rotation L lying on the same first vertical plane and two rolling elements 3 having respective longitudinal axis of rotation L lying on the same second vertical plane, in which the first vertical plane and the second vertical plane are substantially perpendicular.

[0072] The support group 1 can further comprise a plurality of support elements 5, each support element 5 being mounted to the base 2 and being coupled with a respective rolling element 3 so that the latter (or a part thereof), in use, can rotate around the respective support element 5 that is on the other hand rotatably stationary.

[0073] Each support element 5 is coupled with a respective rolling element 3 in an assembled configuration B (shown for example in Figure 19).

[0074] Each support element 5 can comprise a shaft 6 in the form of a pin, each shaft 6 being mounted partially inside a through cavity 7 obtained in each respective rolling element 3 in the assembled configuration B.

[0075] Each shaft 6 comprises a first end 8 and a second end 9 that is opposite the first end 8 and protrude axially out of the through cavity 7 when the shaft 6 is coupled with a respective rolling element 3 in the assembled configuration B.

[0076] Near or at the first end 8 or the second end 9 of each shaft 6 a groove 10 is obtained comprising a rest surface 11 intended to rest on a respective portion of the base 2.

[0077] The rest surface 11 is so shaped that, in a mounting configuration M (shown for example in Figure 3 and 7) in which each support element 5 is coupled with a respective rolling element 3 and mounted to the base 2, a longitudinal axis A of each support element 5 coincides with the longitudinal axis of rotation L of the respective rolling element 3.

[0078] Each longitudinal axis A of the respective support element 5 is thus tilted with respect to the horizontal plane γ by an angle corresponding to the angle of tilt α.

[0079] Each groove 10 can further comprise an abutting surface 12 intended to abut, in the mounting configuration M, on a respective further portion of the base 2 to prevent an axial movement of the respective shaft 6 along the longitudinal axis A, in particular an axial movement in a direction moving away from the vertical axis of rotation Y.

[0080] The groove 10 can be shaped as an at least partially annular step.

[0081] Each groove 10 makes the respective shaft 6 an eccentric shaft.

[0082] Near or at the first end 8 or the second end 9 of each shaft 6 where the groove 10 is not obtained, each support element 5 can comprise a further groove 20, in particular of annular shape, comprising a further rest surface 21 intended to rest on a respective portion of the base 2.

[0083] Also the further rest surface 21, when present, is so shaped that, in the mounting configuration M (shown for example in Figure 3 and 7), a longitudinal axis A of each support element 5 coincides with the longitudinal axis of rotation L of the respective rolling element 3.

[0084] Each further groove 20 can further comprise a further abutting surface 22 (Fig. 6) that can, in use, abut on a respective further portion of the base 2 to prevent an axial movement of the respective shaft 6 along the longitudinal axis A, in particular an axial movement in an approach direction from the vertical axis of rotation Y.

[0085] The base 2 can comprise a plurality of tubular elements 13 that can be connected to form a perimeter portion of the base 2. The perimeter portion of the base 2 can have a substantially octagonal plan shape, as in the embodiment shown in Figure 3. The corners of the octagon can be chamfered by one or more further tubular elements 30.

[0086] The tubular elements 13 and the further tubular elements 30 are, in particular, metal tubes.

[0087] The base 2 can further comprise a plurality of housing seats 14, each housing seat 14 being intended to receive a respective rolling element 3 and a respective support element 5 when they are fitted onto one another in the assembled configuration B.

[0088] Each housing seat 14 can comprise at least a first wall 15 and a second wall 16 that are reciprocally opposite, a first through opening 17 being obtained on the first wall 15, the first wall 15 being in particular open upwards i.e. towards the rotatable resting plate 101, and a second through opening 18 is obtained on a second wall 16, the second through opening 18 being in particular open upwards i.e. towards the rotatable resting plate 101.

[0089] The first through opening 17 and the second through opening 18 are obtained reciprocally opposite and are configured to restingly receive a respective portion of the first end 8 and of the second end 9 of a respective support element 5.

[0090] For example, a portion of surface of the first wall 15 that defines the first through opening 17, in the mounting configuration M, can restingly receive the rest surface 11 and a portion of surface of the second wall 16 that defines the second through opening 18 can restingly receive the further rest surface 21.

[0091] Also, for example, a portion of surface of an inner face 19 of the first wall 15, in the mounting configuration M, can restingly receive the abutting surface 12. In particular, the line that separates the abutting surface12 and the rest surface 11 can come to abut against at least one portion of the corner that separates the inner face 19 of the first wall 15 from the surface of the first wall 15 that defines the first through opening 17.

[0092] Each first through opening 17 and each second through opening 18 can have at least one substantially U-shaped section.

[0093] The portion of surface of the first wall 15 that restingly receives the rest surface 11 and the portion of surface of the second wall 16 that restingly receives the further rest surface 21 can have an arched shape. In particular, can define the lower part of the U shape of the respective section of each first through opening 17 and of each second through opening 18.

[0094] The first wall 15 and / or the second wall 16 of a respective housing seat 14 can be connected to the base 2, for example to a tubular element 13 or to a further tubular element, directly or by one or more connecting plates 31 provided in the base 2.

[0095] The first wall 15 and / or the second wall 16 can be welded to one or more connecting plates 31 or can be coupled with one or more connecting plates 31, for example by interlocking. For example, at least one wing portion 32, in particular a pair of opposite wing portions 32, of the first wall 15 and / or of the second wall 16 can be received in a respective notch 39 obtained in the respective connecting plate 31.

[0096] Each rolling element 3 can comprise a hollow main body 23, at least one friction reducing element 24 and at least one retaining element 25 that, in one coupling configuration of the rolling element 3, are coupled axially along a coupling axis C to make the rolling element 3.

[0097] The coupling axis C is, further, the axis along which a rolling element 3 and the respective support element 5 are coupled.

[0098] The hollow main body 23 has, in particular, a truncated cone shape, and the outer side surface thereof defines the outer frustoconical contact surface 4.

[0099] The hollow main body 23 of each rolling element 3 can be made of plastics, in particular comprising polyamide, still more in particular comprising Nylon, for example loaded with oil, in particular lubricating oil, or glass fibre. For example, the hollow main body 23 of each rolling element 3 can be made of PAG6 Nylon loaded with lubricating oil, or PA6 nylon loaded with glass fibre.

[0100] The hollow main body 23 is provided with a hollow space 33, in particular with cylindrical shape.

[0101] Each hollow friction reducing element 24 has, in particular, a hollow substantially cylindrical shape and comprises a longitudinal cavity 34.

[0102] An inner annular surface 35 of the longitudinal cavity 34 portion of the through cavity 7 of a respective rolling element 3.

[0103] The at least one friction reducing element 24 is fitted inside hollow main body 23 and is splined on a respective support element 5 in the assembled configuration B.

[0104] In other words, each friction reducing element 24 is fitted radially further outside the respective support element 5 and the hollow main body 23 is fitted radially further outside the respective friction reducing element 24, where radially means with reference to the coupling axis C.

[0105] Each friction reducing element 24 can comprise or consist of a bearing, in particular a bearing a rolling elements, for example a cylindrical ball bearing.

[0106] Each friction reducing element 24 can comprise an inner ring 36 splined on a respective support element 5 so as to be integral with the latter and thus be, in use, rotatably stationary like the respective support element 5. In particular, the inner annular surface 35, that, when an inner ring 36 is present is the annular surface of the inner ring 36, can be coupled by interference with notches 26 obtained on the respective support element 5.

[0107] Each friction reducing element 24 can further comprise an outer ring 37 that, in the assembled configuration B, is fitted to the respective hollow main body 23. In particular, the outer ring 37 comprises an outer annular surface 38 coupled, in particular by interference, with an inner surface 27 of the hollow main body 23. In this manner, in use, the outer ring 37 is rotatable around the longitudinal axis of rotation L integrally with the hollow main body 23.

[0108] Each friction reducing element 24 can further comprise a plurality of rolling components, which are not shown in the drawings but are of known type, arranged between the inner ring 36 and the outer ring 37 configured to roll on two opposite tracks obtained on the inner ring 36 and on the outer ring 37.

[0109] In the embodiment shown in the Figures, two friction reducing elements 24 are fitted spaced apart along the coupling axis C.

[0110] The retaining element 25 has, in particular, a substantially annular shape.

[0111] The retaining element 25 can comprise or consist of an O-ring or a Seeger ring.

[0112] The retaining element 25 can be fitted coupled, in particular by interference, with a respective support element 5. In particular, the retaining element 25 is fitted abutting on a side face 39 of the friction reducing element 24. Still more in particular, the retaining element 25 and at least one friction reducing element 24 are fitted near the groove 10.

[0113] The retaining element 25 acts, in particular, as a containing spacer so that the respective rolling element 3 with which it is associated does not move axially and so that the respective rolling element 3 with which it is associated does not interfere with a side thereof against a wall of the respective housing seat 14 in which it is arranged.

[0114] The rotating table 100 can further comprise moving means 104 configured to rotate the rotatable resting plate 101.

[0115] The moving means 104 can comprise motor means configured to generate work necessary to rotate the resting plate 101.

[0116] The moving means 104 can further comprise a pulley element 105 rigidly connected to the rotatable resting plate 101.

[0117] In particular, the pulley element 105 can comprise a hole 106, obtained in a central position of the pulley element 105, suitable for engaging rotatably a pin element 28 provided protruding from a support plate 29 of the base 2 in the assembled configuration for use of the rotating table 100.

[0118] The pulley element 105 can further comprise one or more connecting elements 107 (for example four as in the embodiment shown in Figures) configured to connect stiffly the pulley element 105 to the rotatable resting plate 101 so that the latter rotates, in use, integrally with the pulley element 105.

[0119] The pulley element 105 can comprise a crown wheel or a washer.

[0120] The moving means 104 can further comprise a motion transmission element 108 mounted as a closed loop around the motor means 104 and around the pulley element 105 to transmit a motion from the motor means 104 to the rotatable resting plate 101 by the pulley element 105 so that the rotatable resting plate 101 rotates around the vertical rotation axis Y.

[0121] The motion transmission element 108 is mounted, in particular, to an outer surface of the pulley element 105 and is connected to the motor means to transmit a motion from the motor means to the pulley element 105.

[0122] The motion transmission element 108 can comprise a flexible transmission element like a belt.

[0123] In use, when the drive means 104 is driven, the motor means transmits a motion to the pulley element 105 by the motion transmission element 108. In turn, the pulley element 105 rotates the rotatable resting plate 101 around the vertical rotation axis Y.

[0124] During the rotation of the resting plate 101, a wrapping apparatus wraps with a film a load arranged resting on the upper surface 102 of the rotatable resting plate 101.

[0125] The rotatable resting plate 101 is supported, in a static or rotating position, by the support group 1. The rotation of the rotatable resting plate 101 around the vertical rotation axis Y entails a rotation of the rolling elements 3 around the respective longitudinal axis of rotation L.

[0126] Owing to the frustoconical form of each rolling element 3, the outer frustoconical contact surface 4 of each rolling element 3 of contact with the lower surface 103 of the rotatable resting plate 101 adheres to the lower surface 103 during the rotation of each rolling element 3 around the respective longitudinal axis of rotation L and the measured peripheral speed on each zone of the outer frustoconical contact surface 4 in contact with the lower surface 103 is equal to the peripheral speed of a respective portion of lower surface 103 of the rotatable resting plate 101 that rests on this zone.

[0127] In fact, the outer frustoconical contact surface 4 of each rolling element 3 results in a peripheral speed of the rolling element 3 that varies according to the distance from the vertical rotation axis Y and, by choosing appropriately the dimensions of the outer frustoconical contact surface 4, it is obtained that the peripheral speed of the rolling element 3 is equal to the peripheral speed of the rotatable resting plate 101 on the rolling element 3 - rotatable resting plate 101 contact zones.

[0128] This offers the advantage of lengthening the working life of each rolling element 3 because it is prevented that the rolling elements 3 undergo corresponding slipping and / or friction with respect to the rotatable resting plate 101 because of a difference in peripheral speed along the corresponding contact zones, which would cause wear to the rolling elements and thus replacement of the damaged rolling elements.

[0129] The rolling elements 3 support group 1 thus has the advantage of considerably increasing the productivity of the rotating load wrapping apparatuses that use a rotating table equipped with the support group 1 according to the invention with respect to known wrapping apparatuses, because machine downtime for operations of replacing the rolling elements 3 is significantly reduced.

[0130] Another advantage of the rolling elements 3 support group 1 according to the invention is that it is structurally simple and easily installable in already known rotating load wrapping apparatuses because it is sufficient to replace the known cylindrical rolling elements with the rolling elements 3 with which a respective support element 5 has been coupled and mount each support element 5 in a housing seat 14 of a base even already known that supports the support element 5.

Examples

Embodiment Construction

[0024]With reference to the attached Figures, for the sake of simplicity, identical elements of similar components, unless otherwise stated, have been indicated by the same numbering.

[0025]With reference to the aforementioned Figures, a rotating table according to the invention has been indicated over all by 100 that is configured to rotate a load to be wrapped with a film.

[0026]The rotating table 100 can be associated with or be comprised in, a wrapping apparatus, in particular of the rotating load type, arranged for wrapping the film around the rotating load by the application of a certain number of wrapping coils or strips around the load.

[0027]The rotating table 100 comprises a resting plate 101 intended to receive restingly the load to be wrapped with the film. The resting plate 101 is rotatable around a vertical rotation axis Y, or wrapping axis, so that the load can be wrapped with the film by the wrapping apparatus.

[0028]The resting plate 101 is disc-shaped and comprises an ...

Background of the invention

[0001] The invention relates to a rolling element support group in particular intended to rotatingly support a rotating table, such as a rotating table of a wrapping apparatus for wrapping loads to be palletized.

[0002] The invention also relates to a rotating table provided with such support group.

[0003] Rolling element support groups for a rotating table are known from the prior art in which each of the rolling elements is fitted to a respective seat of a base so as to be able to rotatingly support a rotating plate of the rotating table that rotates around a vertical rotation axis (wrapping axis) in order to be able to wrap a load arranged in use thereupon with a film by means of a wrapping apparatus.

[0004] Each of such prior art rolling elements has a cylindrical shape and is so fitted to the base that a respective longitudinal axis of rotation thereof is arranged radially and perpendicularly to the vertical rotation axis and an outer side surface contacts a lower surface of the rotating plate. During the rotation of the rotating plate around the vertical rotation axis, each rolling element is free to rotate around the respective longitudinal axis of rotation and consecutive portions of the outer side surface of each rolling element contact corresponding consecutive portions of the lower surface of the rotating plate.

[0005] One examples of a rotating table provided with rolling elements di cylindrical shape is known from US2010 / 064906 A.

[0006] In the rolling element support groups for a rotating table that are known from the prior art, the peripheral speed of the rolling element is the same along the entire cylindrical outer side surface thereof, whereas the peripheral speed of the zones - of the rotating plate - in contact with the rolling element varies according to the distance of each zone from the axis of rotation of the rotating plate. In particular, the value of the peripheral speed of the rotating plate measured at the end of the cylindrical rolling element nearer the vertical rotation axis is below the value of the peripheral speed of the rotating plate measured near the further end of the cylindrical rolling element further from the vertical rotation axis.

[0007] The non-uniformity of the peripheral speed of the rotating plate with respect to the peripheral speed of the outer surface of the cylindrical rolling element in contact therewith and thus the peripheral speed difference between the zones that are in reciprocal contact of the rotating plate and of the rolling element generates sliding and friction between the rolling element and rotating plate that entail rapid deterioration of the rolling element. It is accordingly necessary to replace the rolling element because of wear to a part of the rolling element.

[0008] This causes high maintenance and material replacement costs.

[0009] Further, when the rolling elements have to be replaced, the rotating table provided with a prior art rolling element support group cannot be used, thus causing disadvantageous machine downtime. The time for replacing the rolling elements that have to be replaced because of wear thus significantly lower the productivity of known wrapping apparatuses that use this rotating table to wrap a load with a film.

[0010] There is thus ample room for improvement in the prior art.Summary of the invention

[0011] One object of the invention is to improve the prior-art rolling element support groups intended to support a rotating table.

[0012] Another object of the invention is thus to improve rotating tables of known type.

[0013] A further object is to make a rolling element support group for a rotating table that enables the productivity to be considerably increased of a wrapping apparatus with which the rolling element support group according to the invention is associated compared with wrapping apparatuses with known rolling element support groups.

[0014] Still another object is to obtain a rolling element support group that is simple and easily installable in an already known rotating table of rotating load wrapping apparatuses.

[0015] The objects of the invention, and still others are achieved with a rolling element support group and with a rotating table with such a support group according to what is defined in the appended claims.

[0016] In one embodiment, a support group suitable for rotatingly supporting a rotatable resting plate of a rotating table for a wrapping apparatus is provided with: a base; and with a plurality of rolling elements, the rolling elements being configured to be fitted to the base and to support a lower surface of the resting plate rotating around a vertical axis of rotation; each rolling element is freely rotatable around a respective longitudinal axis of rotation. Each rolling element has an outer frustoconical contact surface and the longitudinal axis of rotation di each rolling element is arranged on a respective vertical plane passing through the vertical axis of rotation and is tilted with respect to the lower surface of the resting plate so that the outer contact surface abuts on the lower surface, so that the peripheral speed of each zone of said outer frustoconical contact surface is equal to the peripheral speed of a respective portion of the lower surface that rests on this zone.

[0017] Owing to the rolling element support group for a rotating table according to the invention that comprises rolling elements of frustoconical rather than cylindrical shape like the shape of the rolling elements of the prior art support groups, on each zone of the outer side surface of each rolling element (that is the surface designed to contact a lower surface of a resting plate for the load) a peripheral speed is measurable that is equal to the peripheral speed of a respective portion of lower surface of the resting plate that rests on this zone, independently of the radial position of the rolling element with respect to the vertical axis of rotation of the resting plate.

[0018] This prevents the rolling elements from being subjected to corresponding sliding and / or friction with respect to the resting plate, which would cause wear to the rolling elements and as a result replacement of the damaged rolling elements.

[0019] The working life of the rolling element support group is thus significantly increased.

[0020] This also enables the productivity of the rotating load wrapping apparatuses that use a rotating table according to the invention to be increased significantly with respect to known wrapping apparatuses, because machine downtime for operations of replacing the rolling elements is significantly reduced.

[0021] Lastly, the rolling element support group according to the invention has the advantage of being constructionally simple and easily installable in already known rotating load wrapping apparatuses.

[0022] These above advantages are accordingly detectable in a rotating table equipped with a rolling element support group according to the invention and in a wrapping apparatus comprising a rotating table provided with a rolling element support group according to the invention.Short description of the drawings

[0023] The invention can be better understood and implemented with reference to the appended drawings, which illustrate an embodiment thereof by way of non-limiting example, in which: Figure 1 is a top plan view of a rotating table provided with a rolling element support group according to the invention; Figure 2 is a side view of the rotating table of Figure 1; Figure 3 is a top plan view of a rolling element support group according to the invention; Figure 4 is an exploded perspective view of the rotating table of Figure 1; Figure 5 is a section taken along the plan V-V of Figure 1; Figure 6 is an enlarged detail of Figure 5; Figure 7 is a perspective view of a rolling element of the support group of Figure 3 in a fitting configuration in a housing seat; Figure 8 is a perspective view of a rolling element of the support group of Figure 3 in a position spaced apart from a housing seat; Figure 9 is a side view of the rolling element of Figure 7 in a fitting configuration in a housing seat; Figure 10 is a bottom view of the rolling element of Figure 9 mounted into a housing seat; Figure 11 is a top view of the rolling element of Figure 9 fitted into a housing seat; Figure 12 is a (right) front view of the rolling element of Figure 9 mounted into a housing seat; Figure 13 is a (left) rear view of the rolling element of Figure 9 fitted into a housing seat; Figure 14 is a view like that of Figure 7 taken from another angle; Figure 15 is a view like that of Figure 8 taken from another angle; Figure 16 is a side view of a rolling element and of a respective support element in an assembled configuration; Figure 17 is a (right) front view of the rolling element and of the respective support element of Figure 16; Figure 18 is a (left) rear view of the rolling element and of the respective support element of Figure 16; Figure 19 is a perspective view of the rolling element and of the respective support element of Figure 16; Figure 20 is an exploded view of the rolling element and of the respective support element of Figure 16. Detailed description

[0024] With reference to the attached Figures, for the sake of simplicity, identical elements of similar components, unless otherwise stated, have been indicated by the same numbering.

[0025] With reference to the aforementioned Figures, a rotating table according to the invention has been indicated over all by 100 that is configured to rotate a load to be wrapped with a film.

[0026] The rotating table 100 can be associated with or be comprised in, a wrapping apparatus, in particular of the rotating load type, arranged for wrapping the film around the rotating load by the application of a certain number of wrapping coils or strips around the load.

[0027] The rotating table 100 comprises a resting plate 101 intended to receive restingly the load to be wrapped with the film. The resting plate 101 is rotatable around a vertical rotation axis Y, or wrapping axis, so that the load can be wrapped with the film by the wrapping apparatus.

[0028] The resting plate 101 is disc-shaped and comprises an upper surface 102 on which the load is restingly arranged, and a lower surface 103 opposite the upper surface 102.

[0029] Still with reference to the aforementioned Figures, a support group according to the invention configured to support rotatingly the rotatable resting plate 101 has been indicated overall by 1.

[0030] The resting plate 101, in use, is thus rotatingly supported by the support group 1.

[0031] The rotating table 100 can comprise, or be associated with, the support group 1 according to the invention.

[0032] The resting plate 101 thus acts as a support for the load and is configured to rotate the load around the vertical rotation axis Y during a wrapping cycle during which the load - when rotated by the rotatable resting plate 101 - is wrapped by the wrapping film in order to apply a set number of film wrapping coils to the load.

[0033] In other words, the support group 1 is suitable for rotatingly supporting the rotatable resting plate 101 of the rotating table 100. In particular, the support group 1 engages the lower surface 103 to rotatingly support the rotatable resting plate 101.

[0034] The resting plate 101 and the load are rotated around the vertical rotation axis Y along a wrapping direction, for example a clockwise rotation direction.

[0035] The film is, in particular, unwound from a reel.

[0036] The vertical rotation axis Y is substantially vertical, i.e. substantially parallel to the gravity acceleration vector.

[0037] The load can be arranged resting on a support that is positionable on the resting plate 101 like, for example, a pallet, i.e. can be a palletized load.

[0038] The load can consist of a product or of a plurality of products, for example, grouped on a pallet.

[0039] The film is made of an elastic material and / or plastics, for example can be an extendible film having elasticity that is such as to be able to be applied and shaped around the load and, at the same time, is such as to keep the latter together in a stable manner. Further, the film can be, in particular, a macroperforated film and / or a biodegradable film and / or a heat-sensitive film.

[0040] The support group 1 is provided with a base 2.

[0041] The base 2 can be arranged resting on a floor P or a terrain.

[0042] The support group 1 is further provided with a plurality of rolling elements 3, which rolling elements 3 are configured to be mounted to the base 2 and to support the lower surface 103 of the resting plate 101 rotating around the vertical axis Y of rotation.

[0043] The lower surface 103 is, in particular, flat and lies on a horizontal plane γ that is substantially perpendicular to the vertical axis of rotation Y.

[0044] Each rolling element 3 is freely rotatable around a respective longitudinal axis of rotation R.

[0045] Each rolling element 3 has an outer frustoconical contact surface 4. The outer frustoconical contact surface 4 of each rolling element 3 is configured to contact, in use, a respective portion of the lower surface 103.

[0046] Each rolling element 3 has a substantially frustoconical shape. In particular, each rolling element 3 has a hollow truncated shape. The outer frustoconical contact surface 4 of each rolling element 3 is the side surface of each truncated cone.

[0047] In use, in order to enable the support group 1 to support the resting plate 101 while it is rotated, the rolling elements 3 have to be able to abut on (i.e. come into contact with, adhere to) the lower surface 103 of the resting plate 101 from below. In particular, the rolling elements 3 and the lower surface 103 engage by contact in a contact zone. The extent of the contact zone, in particular along a horizontal direction that is substantially perpendicular to an apothem of the truncated cone, depends on the material with which each rolling element 3 is made, in particular near the outer frustoconical contact surface 4. For example, the contact zone can extend along an apothem of the truncated cone or can comprise a strip that comprises and extends near an apothem of the truncated cone. The outer frustoconical contact surface 4 of each rolling element 3 can be made of plastics, in particular comprising polyamide, still more in particular comprising Nylon, for example loaded with oil, in particular lubricating oil, or glass fibre. For example, the outer frustoconical contact surface 4 of each rolling element 3 can be made of PAG6 Nylon loaded with lubricating oil, or PA6 nylon loaded with glass fibre.

[0048] The rotation of the resting plate 101 around the vertical rotation axis Y results in rotation of the rolling elements 3 around the respective longitudinal axis of rotation L because of sliding friction between the lower surface 103 and the outer contact surface 4, when the resting plate 101 is rotated.

[0049] The rolling elements 3 thus each behave in use like a sort of idling supporting wheel, i.e. free to rotate around the respective axis of rotation, configured to rotatably support the rotatable resting plate 101.

[0050] The longitudinal axis of rotation L of each rolling element 3 is arranged on a respective vertical plane passing through the vertical axis Y of rotation and is tilted with respect to the lower surface 103 of the resting plate 101 so that the outer frustoconical contact surface 4 abuts on the lower surface 103 of the resting plate 101 so that the peripheral speed of each zone of the outer frustoconical contact surface 4 is equal to the peripheral speed of a respective portion of the lower surface 103 that rests on this zone.

[0051] A zone of the outer frustoconical contact surface 4 means a point or an area of the outer frustoconical contact surface 4, for example an annular sector, in which the peripheral speed of the rolling element 3 is considerably constant.

[0052] Respective portion of the lower surface 103 means a point or an area of the lower surface 103, for example an area, for example an annular sector, in the peripheral speed of the rotatable resting plate 101 is considerably constant.

[0053] The portion of the lower surface 103 is considered to be "respective" of a zone of the outer frustoconical contact surface 4 (and vice versa) because it contacts this zone, i.e. it is positioned directly above this zone along the acceleration vector of terrestrial gravity.

[0054] In other words, on each contact portion / point between the outer frustoconical contact surface 4 and the lower surface 103 the measured peripheral speed is the same owing to the truncated cone shape of each rolling element 3, to the arrangement of the longitudinal axis of rotation L of each rolling element 3 and to mounting each rolling element 3 in contact with the lower surface 103 of the resting plate 101 in the contact zone.

[0055] Owing to the fact that the peripheral speed of the resting plate 101 and of each rolling element 3 is the same along the contact zone considering corresponding zones of the lower surface 103 and of the outer frustoconical contact surface 4 (i.e. reciprocal rest areas or points, i.e. positioned one above the other along the acceleration vector of terrestrial gravity), sliding and / or friction between the resting plate 101 and parts of each rolling element 3 is avoided. In this manner, the working life of the rolling elements 3 is significantly extended compared with that of prior-art cylindrical cylinders because the absence of sliding and / or friction due to differences in peripheral speed does not entail uneven deterioration of the rolling element 3 along a direction that is radial with respect to the vertical axis of rotation Y.

[0056] Each longitudinal axis of rotation L of the respective rolling element 3 can have a tilt that is such as to be nearer the lower surface 103 of the resting plate 101 in the direction of approach to the vertical axis Y of rotation.

[0057] In other words, if one considers a direction of approach towards the vertical axis of rotation Y, each longitudinal axis of rotation L progressively approaches the lower surface 103 of the resting plate 101.

[0058] Each longitudinal axis of rotation L of the respective rolling element 3 is tilted with respect to the horizontal plane γ on which the lower surface 103 rests by an angle of tilt α comprised between 2° and 4°, in particular by an angle of tilt equal to 3°.

[0059] Each longitudinal axis of rotation L of the respective rolling element 3 is, in other words, transverse to the horizontal plane γ on which the lower surface 103 of the rotatable resting plate 101 lies.

[0060] Each longitudinal axis of rotation L of the respective rolling element 3 projects substantially radially from the vertical axis of rotation Y.

[0061] The vertical axis of rotation Y can be a central axis of the base 2.

[0062] The formulas will be supplied below that are used to determine a value of the lesser radius r2 of the truncated cone of each rolling element 3 (from which it is possible to calculate the angle of conicity of the truncated cone, i.e. the angle between the longitudinal axis of rotation L of each rolling element 3 and the apothem of the truncated cone of each rolling element 3) so that, in the respective points of contact between each rolling element 3 and the rotatable resting plate 101 the outer frustoconical contact surface 4 of each rolling element 3 has the same peripheral speed even when the radial position of the point of contact decreases with respect to the vertical axis of rotation Y.

[0063] The lesser radius r2 is the radius of the lesser base of the truncated cone. If the truncated cone is chamfered and does not have corners on the lesser base, the lesser base is considered to be an area of the rolling element 3 comprised in a circle of a section taken on a plane that is perpendicular to the longitudinal axis of rotation L extending nearer the vertical axis of rotation Y and which abuts on the lower surface 103.

[0064] The data from which it is possible to calculate the lesser radius r2 are: a value of the rotation speed n of the resting plate 101; for example n can be equal to 10 RPM; a value of the greater radius r1 of the truncated cone; for example, r1 can be equal to 26.5 mm; the greater radius r1 is the radius of the greater base of the truncated cone; if the truncated cone is chamfered and does not have corners on the greater base, an area of the rolling element 3 comprised in a circle of a section taken on a plane that is perpendicular to the longitudinal axis of rotation L extending further from the vertical axis of rotation Y and which abuts on the lower surface 103 is considered to be the greater base; a value of a greater radius R1 of the resting plate 101 in the point of contact p1 of the outer frustoconical contact surface 4 of a rolling element 3 with the lower surface 103 at a greater distance from the vertical rotation axis Y; for example, R1 can be equal to 750 mm; a value of a lesser radius R2 of the resting plate 101 in the point of contact p2 of the outer frustoconical contact surface 4 of a rolling element 3 with the lower surface 103 at a lesser distance from the vertical rotation axis Y; for example, R2 can be equal to 716 mm.

[0065] The peripheral speed Vp1 in the point of contact p1 resting plate 101-rolling element 3 at a greater distance from the vertical rotation axis Y is given by: Vp 1 = w × R 1 where w is the angular speed of the resting plate 101 that is given by w = 2 πn 60 whereas the peripheral speed Vp2 in the point of contact p2 resting plate 101-rolling element 3 at a lesser distance from the vertical rotation axis Y is given by: Vp 2 = w × R 2

[0066] The angular speed of each rolling element 3, each rolling element 3 being a stiff body, is the same along an approach direction to the vertical axis of rotation Y whereas the peripheral speed varies. By making the peripheral speed of a rolling element 3 in the point of contact p1 the same as that of the resting plate 101 (i.e. Vp1 ) in the same point and the peripheral speed in the point of contact p2 of a rolling element 3 the same as that of the resting plate 101 (i.e. Vp2 ) in the same point, the lesser radius r2 of the rolling element can be obtained by the following steps: Z = Vp 1 r 1 where Z is the angular speed of the rolling element 3 and Vp 2 = Z × r 2 = Vp 1 r 1 × r 2 from which we obtain r 2 = Vp 2 Vp 1 × r 1 = 2 πn 60 R 2 × 60 2 πnR 1 × r 1 i.e. r 2 = R 2 R 1 r 1

[0067] Thus by choosing each lesser radius r2 of the truncated cone of the rolling elements 3 with a value obtained from the above equation (known R1, R2 and r1) a peripheral speed of the rolling element 3 is maintained along the contact zone with the resting plate 101 corresponding to that of the resting plate 101 considering respective areas 3 (or points) of contact of the outer frustoconical surface 4 with the lower surface 103.

[0068] For example, if r1 = 26.5 mm, R1 = 750 mm and R2 = 716 mm, r2 must be chosen equal to 50 mm.

[0069] In the same way, by varying the greater radius r1 and the length of the tapered part of contact of the wheel (i.e. R1-R2) and repeating the above calculations the conicity that results therefrom will always have the same effects in any position of the table.

[0070] The plurality of rolling elements 3 can comprise at least four rolling elements 3 arranged angularly spaced from each other, in particular angularly equidistant from each other.

[0071] The plurality of rolling elements 3 can comprise two rolling elements 3 having respective longitudinal axis of rotation L lying on the same first vertical plane and two rolling elements 3 having respective longitudinal axis of rotation L lying on the same second vertical plane, in which the first vertical plane and the second vertical plane are substantially perpendicular.

[0072] The support group 1 can further comprise a plurality of support elements 5, each support element 5 being mounted to the base 2 and being coupled with a respective rolling element 3 so that the latter (or a part thereof), in use, can rotate around the respective support element 5 that is on the other hand rotatably stationary.

[0073] Each support element 5 is coupled with a respective rolling element 3 in an assembled configuration B (shown for example in Figure 19).

[0074] Each support element 5 can comprise a shaft 6 in the form of a pin, each shaft 6 being mounted partially inside a through cavity 7 obtained in each respective rolling element 3 in the assembled configuration B.

[0075] Each shaft 6 comprises a first end 8 and a second end 9 that is opposite the first end 8 and protrude axially out of the through cavity 7 when the shaft 6 is coupled with a respective rolling element 3 in the assembled configuration B.

[0076] Near or at the first end 8 or the second end 9 of each shaft 6 a groove 10 is obtained comprising a rest surface 11 intended to rest on a respective portion of the base 2.

[0077] The rest surface 11 is so shaped that, in a mounting configuration M (shown for example in Figure 3 and 7) in which each support element 5 is coupled with a respective rolling element 3 and mounted to the base 2, a longitudinal axis A of each support element 5 coincides with the longitudinal axis of rotation L of the respective rolling element 3.

[0078] Each longitudinal axis A of the respective support element 5 is thus tilted with respect to the horizontal plane γ by an angle corresponding to the angle of tilt α.

[0079] Each groove 10 can further comprise an abutting surface 12 intended to abut, in the mounting configuration M, on a respective further portion of the base 2 to prevent an axial movement of the respective shaft 6 along the longitudinal axis A, in particular an axial movement in a direction moving away from the vertical axis of rotation Y.

[0080] The groove 10 can be shaped as an at least partially annular step.

[0081] Each groove 10 makes the respective shaft 6 an eccentric shaft.

[0082] Near or at the first end 8 or the second end 9 of each shaft 6 where the groove 10 is not obtained, each support element 5 can comprise a further groove 20, in particular of annular shape, comprising a further rest surface 21 intended to rest on a respective portion of the base 2.

[0083] Also the further rest surface 21, when present, is so shaped that, in the mounting configuration M (shown for example in Figure 3 and 7), a longitudinal axis A of each support element 5 coincides with the longitudinal axis of rotation L of the respective rolling element 3.

[0084] Each further groove 20 can further comprise a further abutting surface 22 (Fig. 6) that can, in use, abut on a respective further portion of the base 2 to prevent an axial movement of the respective shaft 6 along the longitudinal axis A, in particular an axial movement in an approach direction from the vertical axis of rotation Y.

[0085] The base 2 can comprise a plurality of tubular elements 13 that can be connected to form a perimeter portion of the base 2. The perimeter portion of the base 2 can have a substantially octagonal plan shape, as in the embodiment shown in Figure 3. The corners of the octagon can be chamfered by one or more further tubular elements 30.

[0086] The tubular elements 13 and the further tubular elements 30 are, in particular, metal tubes.

[0087] The base 2 can further comprise a plurality of housing seats 14, each housing seat 14 being intended to receive a respective rolling element 3 and a respective support element 5 when they are fitted onto one another in the assembled configuration B.

[0088] Each housing seat 14 can comprise at least a first wall 15 and a second wall 16 that are reciprocally opposite, a first through opening 17 being obtained on the first wall 15, the first wall 15 being in particular open upwards i.e. towards the rotatable resting plate 101, and a second through opening 18 is obtained on a second wall 16, the second through opening 18 being in particular open upwards i.e. towards the rotatable resting plate 101.

[0089] The first through opening 17 and the second through opening 18 are obtained reciprocally opposite and are configured to restingly receive a respective portion of the first end 8 and of the second end 9 of a respective support element 5.

[0090] For example, a portion of surface of the first wall 15 that defines the first through opening 17, in the mounting configuration M, can restingly receive the rest surface 11 and a portion of surface of the second wall 16 that defines the second through opening 18 can restingly receive the further rest surface 21.

[0091] Also, for example, a portion of surface of an inner face 19 of the first wall 15, in the mounting configuration M, can restingly receive the abutting surface 12. In particular, the line that separates the abutting surface12 and the rest surface 11 can come to abut against at least one portion of the corner that separates the inner face 19 of the first wall 15 from the surface of the first wall 15 that defines the first through opening 17.

[0092] Each first through opening 17 and each second through opening 18 can have at least one substantially U-shaped section.

[0093] The portion of surface of the first wall 15 that restingly receives the rest surface 11 and the portion of surface of the second wall 16 that restingly receives the further rest surface 21 can have an arched shape. In particular, can define the lower part of the U shape of the respective section of each first through opening 17 and of each second through opening 18.

[0094] The first wall 15 and / or the second wall 16 of a respective housing seat 14 can be connected to the base 2, for example to a tubular element 13 or to a further tubular element, directly or by one or more connecting plates 31 provided in the base 2.

[0095] The first wall 15 and / or the second wall 16 can be welded to one or more connecting plates 31 or can be coupled with one or more connecting plates 31, for example by interlocking. For example, at least one wing portion 32, in particular a pair of opposite wing portions 32, of the first wall 15 and / or of the second wall 16 can be received in a respective notch 39 obtained in the respective connecting plate 31.

[0096] Each rolling element 3 can comprise a hollow main body 23, at least one friction reducing element 24 and at least one retaining element 25 that, in one coupling configuration of the rolling element 3, are coupled axially along a coupling axis C to make the rolling element 3.

[0097] The coupling axis C is, further, the axis along which a rolling element 3 and the respective support element 5 are coupled.

[0098] The hollow main body 23 has, in particular, a truncated cone shape, and the outer side surface thereof defines the outer frustoconical contact surface 4.

[0099] The hollow main body 23 of each rolling element 3 can be made of plastics, in particular comprising polyamide, still more in particular comprising Nylon, for example loaded with oil, in particular lubricating oil, or glass fibre. For example, the hollow main body 23 of each rolling element 3 can be made of PAG6 Nylon loaded with lubricating oil, or PA6 nylon loaded with glass fibre.

[0100] The hollow main body 23 is provided with a hollow space 33, in particular with cylindrical shape.

[0101] Each hollow friction reducing element 24 has, in particular, a hollow substantially cylindrical shape and comprises a longitudinal cavity 34.

[0102] An inner annular surface 35 of the longitudinal cavity 34 portion of the through cavity 7 of a respective rolling element 3.

[0103] The at least one friction reducing element 24 is fitted inside hollow main body 23 and is splined on a respective support element 5 in the assembled configuration B.

[0104] In other words, each friction reducing element 24 is fitted radially further outside the respective support element 5 and the hollow main body 23 is fitted radially further outside the respective friction reducing element 24, where radially means with reference to the coupling axis C.

[0105] Each friction reducing element 24 can comprise or consist of a bearing, in particular a bearing a rolling elements, for example a cylindrical ball bearing.

[0106] Each friction reducing element 24 can comprise an inner ring 36 splined on a respective support element 5 so as to be integral with the latter and thus be, in use, rotatably stationary like the respective support element 5. In particular, the inner annular surface 35, that, when an inner ring 36 is present is the annular surface of the inner ring 36, can be coupled by interference with notches 26 obtained on the respective support element 5.

[0107] Each friction reducing element 24 can further comprise an outer ring 37 that, in the assembled configuration B, is fitted to the respective hollow main body 23. In particular, the outer ring 37 comprises an outer annular surface 38 coupled, in particular by interference, with an inner surface 27 of the hollow main body 23. In this manner, in use, the outer ring 37 is rotatable around the longitudinal axis of rotation L integrally with the hollow main body 23.

[0108] Each friction reducing element 24 can further comprise a plurality of rolling components, which are not shown in the drawings but are of known type, arranged between the inner ring 36 and the outer ring 37 configured to roll on two opposite tracks obtained on the inner ring 36 and on the outer ring 37.

[0109] In the embodiment shown in the Figures, two friction reducing elements 24 are fitted spaced apart along the coupling axis C.

[0110] The retaining element 25 has, in particular, a substantially annular shape.

[0111] The retaining element 25 can comprise or consist of an O-ring or a Seeger ring.

[0112] The retaining element 25 can be fitted coupled, in particular by interference, with a respective support element 5. In particular, the retaining element 25 is fitted abutting on a side face 39 of the friction reducing element 24. Still more in particular, the retaining element 25 and at least one friction reducing element 24 are fitted near the groove 10.

[0113] The retaining element 25 acts, in particular, as a containing spacer so that the respective rolling element 3 with which it is associated does not move axially and so that the respective rolling element 3 with which it is associated does not interfere with a side thereof against a wall of the respective housing seat 14 in which it is arranged.

[0114] The rotating table 100 can further comprise moving means 104 configured to rotate the rotatable resting plate 101.

[0115] The moving means 104 can comprise motor means configured to generate work necessary to rotate the resting plate 101.

[0116] The moving means 104 can further comprise a pulley element 105 rigidly connected to the rotatable resting plate 101.

[0117] In particular, the pulley element 105 can comprise a hole 106, obtained in a central position of the pulley element 105, suitable for engaging rotatably a pin element 28 provided protruding from a support plate 29 of the base 2 in the assembled configuration for use of the rotating table 100.

[0118] The pulley element 105 can further comprise one or more connecting elements 107 (for example four as in the embodiment shown in Figures) configured to connect stiffly the pulley element 105 to the rotatable resting plate 101 so that the latter rotates, in use, integrally with the pulley element 105.

[0119] The pulley element 105 can comprise a crown wheel or a washer.

[0120] The moving means 104 can further comprise a motion transmission element 108 mounted as a closed loop around the motor means 104 and around the pulley element 105 to transmit a motion from the motor means 104 to the rotatable resting plate 101 by the pulley element 105 so that the rotatable resting plate 101 rotates around the vertical rotation axis Y.

[0121] The motion transmission element 108 is mounted, in particular, to an outer surface of the pulley element 105 and is connected to the motor means to transmit a motion from the motor means to the pulley element 105.

[0122] The motion transmission element 108 can comprise a flexible transmission element like a belt.

[0123] In use, when the drive means 104 is driven, the motor means transmits a motion to the pulley element 105 by the motion transmission element 108. In turn, the pulley element 105 rotates the rotatable resting plate 101 around the vertical rotation axis Y.

[0124] During the rotation of the resting plate 101, a wrapping apparatus wraps with a film a load arranged resting on the upper surface 102 of the rotatable resting plate 101.

[0125] The rotatable resting plate 101 is supported, in a static or rotating position, by the support group 1. The rotation of the rotatable resting plate 101 around the vertical rotation axis Y entails a rotation of the rolling elements 3 around the respective longitudinal axis of rotation L.

[0126] Owing to the frustoconical form of each rolling element 3, the outer frustoconical contact surface 4 of each rolling element 3 of contact with the lower surface 103 of the rotatable resting plate 101 adheres to the lower surface 103 during the rotation of each rolling element 3 around the respective longitudinal axis of rotation L and the measured peripheral speed on each zone of the outer frustoconical contact surface 4 in contact with the lower surface 103 is equal to the peripheral speed of a respective portion of lower surface 103 of the rotatable resting plate 101 that rests on this zone.

[0127] In fact, the outer frustoconical contact surface 4 of each rolling element 3 results in a peripheral speed of the rolling element 3 that varies according to the distance from the vertical rotation axis Y and, by choosing appropriately the dimensions of the outer frustoconical contact surface 4, it is obtained that the peripheral speed of the rolling element 3 is equal to the peripheral speed of the rotatable resting plate 101 on the rolling element 3 - rotatable resting plate 101 contact zones.

[0128] This offers the advantage of lengthening the working life of each rolling element 3 because it is prevented that the rolling elements 3 undergo corresponding slipping and / or friction with respect to the rotatable resting plate 101 because of a difference in peripheral speed along the corresponding contact zones, which would cause wear to the rolling elements and thus replacement of the damaged rolling elements.

[0129] The rolling elements 3 support group 1 thus has the advantage of considerably increasing the productivity of the rotating load wrapping apparatuses that use a rotating table equipped with the support group 1 according to the invention with respect to known wrapping apparatuses, because machine downtime for operations of replacing the rolling elements 3 is significantly reduced.

[0130] Another advantage of the rolling elements 3 support group 1 according to the invention is that it is structurally simple and easily installable in already known rotating load wrapping apparatuses because it is sufficient to replace the known cylindrical rolling elements with the rolling elements 3 with which a respective support element 5 has been coupled and mount each support element 5 in a housing seat 14 of a base even already known that supports the support element 5.

Examples

Embodiment Construction

[0024]With reference to the attached Figures, for the sake of simplicity, identical elements of similar components, unless otherwise stated, have been indicated by the same numbering.

[0025]With reference to the aforementioned Figures, a rotating table according to the invention has been indicated over all by 100 that is configured to rotate a load to be wrapped with a film.

[0026]The rotating table 100 can be associated with or be comprised in, a wrapping apparatus, in particular of the rotating load type, arranged for wrapping the film around the rotating load by the application of a certain number of wrapping coils or strips around the load.

[0027]The rotating table 100 comprises a resting plate 101 intended to receive restingly the load to be wrapped with the film. The resting plate 101 is rotatable around a vertical rotation axis Y, or wrapping axis, so that the load can be wrapped with the film by the wrapping apparatus.

[0028]The resting plate 101 is disc-shaped and comprises an ...

Claims

1. Support group (1) suitable for rotatingly supporting a rotatable resting plate (101) of a rotating table (100) for a wrapping apparatus, said support group (1) being provided with: - a base (2); and with - a plurality of rolling elements (3), said rolling elements (3) being configured to be fitted to said base (2) and for supporting a lower surface (103) of said resting plate (101) rotating around a vertical axis (Y) of rotation; each rolling element (3) being freely rotatable around a respective longitudinal axis of rotation (L); said support group (1) being characterized in that each rolling element (3) has an outer frustoconical contact surface (4) and in that the longitudinal axis of rotation (L) of each rolling element (3) is arranged on a respective vertical plane passing through said vertical axis (Y) of rotation and is tilted with respect to said lower surface (103) of said resting plate (101) so that said outer frustoconical contact surface (4) abuts on said lower surface (103), so that the peripheral speed of each zone of said outer frustoconical contact surface (4) is the same as the peripheral speed of a respective portion of said lower surface (103) that rests on said zone.

2. Support group (1) according to claim 1, wherein each longitudinal axis of rotation (L) of the respective rolling element (3) is tilted such as to be nearer said lower surface (103) of said rotatable resting plate (101) in a direction approaching said vertical axis (Y) of rotation.

3. Support group (1) according to claim 2, wherein each longitudinal axis of rotation (L) of the respective rolling element (3) is tilted with respect to a horizontal plane (γ) on which said lower surface (103) lies by an angle of tilt (α) ranging from 2° to 4°, in particular by an angle of tilt equal to 3°.

4. Support group (1) according to any one of claims 1 to 3, wherein said plurality of rolling elements (3) comprises at least four rolling elements (3) arranged angularly spaced apart from one another, in particular angularly equidistant from one another.

5. Support group (1) according to claim 4, wherein said plurality of rolling elements (3) comprises two rolling elements (3) having respective longitudinal axis of rotation (L) lying on the same first vertical plane and two rolling elements (3) having respective longitudinal axis of rotation (L) lying on the same second vertical plane, said first vertical plane and said second vertical plane being substantially perpendicular.

6. Support group (1) according to any one of claims 1 to 5, and further comprising a plurality of support elements (5), each support element (5) being fitted to said base (2) and being coupled with a respective rolling element (3) so that the latter, in use, can rotate around the respective support element (5) that, in use, is rotatably stationary.

7. Support group (1) according to claim 6, as claim 4 is appended to claim 3 or as claim 6 is appended to any one of claims 3 to 5, as claim 4 is appended to claim 3, wherein each support element (5) comprises a shaft (6), each shaft (6) being fitted partially inside a through cavity (7) obtained in each respective rolling element (3), each shaft (6) comprising a first end (8) and a second end (9) opposite said first end (8) protruding axially outside said through cavity (7) in an assembled configuration (B) in which a rolling element (3) and a respective support element (5) are coupled together, near or at said first end (8) or said second end (9) a groove (10) being obtained comprising a rest surface (11) intended to rest on a respective portion of said base (2), said rest surface (11) being so shaped that, in a mounting configuration (M) in which each support element (5) is coupled with a respective rolling element (3) and fitted to said base (2), a longitudinal axis (A) of each support element (5) coincides with said longitudinal axis of rotation (L) of the respective rolling element (3).

8. Support group (1) according to claim 7, wherein each groove (10) further comprises an abutting surface (12) intended to come to abut against a respective further portion of said base (2) to prevent an axial movement of said shaft (6) along said longitudinal axis (A) in particular an axial movement in a direction away from said axis of vertical rotation (Y).

9. Support group (1) according to claim 7 or 8, wherein said base (2) comprises a plurality of housing seats (14), each housing seat (14) being intended to receive a respective rolling element (3) and a respective support element (5) in said assembled configuration (B), each housing seat (14) comprising at least one first wall (15) and a second wall (16) that are mutually opposite, a first through opening (17) being obtained on said first wall (15) in particular open upwards, i.e. towards said rotatable resting plate (101), and a second through opening (18) being obtained on said second wall (16), in particular open upwards, i.e. towards said rotatable resting plate (101), said first through opening (17) and said second through opening (18) being obtained that are mutually opposite and being configured for restingly receiving a respective portion of said first end (8) and of said second end (9) of a respective support element (5).

10. Support group (1) according to claim 9, wherein each first through opening (17) and each second through opening (18) have at least one substantially U-shaped section.

11. Support group (1) according to any one of claims 7 to 10, wherein each rolling element (3) comprises a hollow main body (23) of frustoconical shape, at least one hollow friction-reducing element (24) of substantially hollow cylindrical shape and at least one retaining element (25) of substantially annular shape that, in a coupling configuration (C) of each rolling element (3), are coupled axially to make said rolling element (3), said at least one friction-reducing element (24) being fitted inside said main body (23) and being splined on a respective support element (5), an inner annular surface (35) of said at least one friction-reducing element (24) defining a portion of said through cavity (7).

12. Rotating table (100) comprising: - a rotatable resting plate (101) intended to supportingly receive a load, said rotatable resting plate (101) being rotatable around an axis of vertical rotation (Y) so that said load can be wrapped in a film by a wrapping apparatus; and - a support group (1) according to any one of claims 1 to 11 configured to rotatingly support said rotatable resting plate (101).

13. Rotating table (1) according to claim 12 and further comprising moving means (104) configured to rotate said rotatable resting plate (101), said moving means (104) comprising motor means, a pulley element (105) stiffly connected to said rotatable resting plate (101) and a motion transmission element (108) fitted as a closed loop to said motor means and to said pulley element (105) to transmit a motion from said motor means to said rotatable resting plate (101) by said pulley element (105) so that said rotatable resting plate (101) rotates around said axis of vertical rotation (Y).

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