TWO-PIECES CAGE FOR FRICTION RING TO BE USED IN FRICTION DAMPERS FOR WASHING MACHINES

Abstract

Cage (1) configured to house thereinside a friction ring to be used in friction dampers for washing machines, characterized in that it comprises a first (11) and a second piece (12) configured to be coupled by introducing the one in the other one.

Claims

1. A cage (1) configured to house thereinside a friction ring to be used in friction dampers for washing machines, said cage (1) comprising a first piece (11) and a second piece (12) configured to be coupled by introducing said first piece (11) into said second piece (12), said cage (1) being substantially of cylindrical shape and is being provided with a through-hole inside which a piston (4) is housed slidingly.

2. The cage (1) according to claim 1, wherein on said piston (4), spring limit stops (2) can be installed from opposite portions with respect to said cage (1).

3. The cage (1) according to claim 1, wherein said first piece (11) and second piece (12) are each shaped as cylinder crowns and comprise each a cylinder wall (111, 121) provided at an end with an end stop (112, 122), said cylinder walls (111,121) being configured so that they can be coupled with clearance and said stop surfaces (112, 122) being provided with an inner edge of circular shape.

4. The cage (1) according to claim 3, wherein on that cylinder wall (111) outer surface of an inner portion, there are a plurality of projections (113) having a wedge shape, configured to engage a plurality of housings (123) realized on the cylinder wall (121) of an outer portion of said second piece (12).

5. The cage (1) according to claim 4, wherein said outer portion of said second piece (12) is provided, on its own outer surface (121), with ribs (124) configured so that the surface (121) of said outer portion of the cage is stiffened.

6. The cage (1) according to claim 3, wherein on the cylinder wall (111) of the inner portion (11) there are open slots (116) configured to reduce the resistance to the deformation of said wall (111).

7. The cage (1) according to claim 1, further comprising an outer portion (22) of the cage, said outer portion (22) comprises a plurality of housings shaped as rectangular holes, aligned on a plurality of outer circumferences at different distance from a stop (222).

8. The friction damper for washing machines, comprising a cage (1) of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The invention will be now described in detail by means of some preferred embodiments, with reference to the appended FIGS. 1 to 7.

[0013] In FIG. 1 there is shown an axonometric view of a first embodiment of the cage, whose elements are shown disassembled in FIGS. 2a, 2b, 3a, 3b.

[0014] In FIG. 4 there is shown the same embodiment assembled on a piston. A second embodiment is shown in FIGS. 5 to 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] With reference to FIG. 4, the cage (1) according to the invention is configured to house thereinside a friction ring (not shown in FIG. 4). It is shaped substantially as a cylinder and is hollow inside so that it can house slidingly a piston (4), on which there are shown installed also spring limit stops (2) and the closing plug (3) of the shell of the damper.

[0016] Moreover, the cage is configured so that the piston can project with respect to the same from both portions, as it is shown for example in the appended FIG. 4, so that it is possible to install spring limit stops (2) around the piston, from both portions of the cage. In this manner, the cage is movable both with respect to the piston (4) and with respect to the closing plug (3). Moreover, the cage is movable with respect to the shell as well (not shown in FIG. 4) of the damper.

[0017] Since the limit stops (2) limit the possibility of the cage (1) to slide with respect to the shell, their provision allows to define movement areas of the piston in which the cage (and so the friction ring) are integral to the piston (4), and movement areas of the piston in which there is relative movement between cage (and so friction ring) and piston (4). Obviously, the damping force is exerted only when there is relative movement between cage and piston.

[0018] The cage (1) is made up of two pieces (11, 12) shown in FIGS. 2 and 3, respectively, configured to be coupled by introducing the one in the other one.

[0019] The two pieces are shaped as a cylindrical crown provided at an end with an end stop. It is to be said that with axial direction it is intended the direction of the symmetrical axis of said pieces. In FIG. 2-a, where it is shown a portion (11) which in the coupling is inside, both the cylindrical wall (111) and the end stop (112) are shown. On the outer surface of the cylindrical wall (111) there are realized a plurality of projections (113) with wedge shape, the wedge point being oriented to the opposite portion with respect to said stop (112).

[0020] In FIG. 3 it is shown the portion (12) which in the coupling is outside. Both the cylindrical wall (121) and the end stop (122) are shown. On the cylindrical wall (121) of the outer piece (12) there are realized a plurality of holesor housings (123), preferably in rectangular shape, spaced on the circumference so that they each are at a relative wedge projection (113).

[0021] The cylinder walls (111, 121) of the inner (11) and outer piece (12) of the cage (1) are configured so that they can be coupled with clearance, the outer radius of the cylinder wall (111) of the first piece (11) being slightly lower than the inner radius of the cylinder wall (121) of the outer piece (12).

[0022] The projections in wedge shape (113) are such that, by coupling the two pieces (11, 12) along the axial direction the point (114) of each wedge (113) is introduced firstly inside the cylinder wall (121) of the outer piece (12) and, after, deforms slightly and elastically the two cylinder walls (111, 121) until it is positioned, as shown in FIG. 1, inside its own housing (123). When the spring deformation of the two cylinder walls (111, 121) is ended the assembly of projections (113) is constrained to respective housings (123), and in particular the rear wall (115) of each wedge (113) strikes against the surface (125) facing outside of the respective housing (123). This occurs since, as it is shown in figures, the rear portions (115) of all the wedges (113) are aligned with each other at the same distance from the stop (112).

[0023] Before assembling the two pieces (11, 12) it is possible to introduce inside the first portion (11) a friction ring, realized in polyurethane or other material. The ring, once the cage (1) is assembled, is trapped between the two stops (112, 122) and cannot go out from its own seat unless it is deformed inwards, which is avoided by the piston (4) in the following introduced inside the cage (1). Obviously in case of using friction strips, the same can be introduced inside the cage (1), after it is assembled. Realizing the cage (1) in two pieces allows to obtain stop surfaces (112, 122) which have a circular inner edge and no interruptions, since each one of the two pieces does not have undercuts for realizing these surfaces.

[0024] Preferably, but not limitingly, the outer portion (12) has, on its outer surface (121), ribs (124) with the double function of stiffening the surface of the cage and of being used to limit the relative rotation between cage and shell of the damper. Moreover, preferably, on the cylinder wall (111) of the inner portion (11) there are realized open slots (116) which are used to reduce resistance to deformation of the same wall.

[0025] According to another embodiment shown in FIGS. 5, 6 and 7, the outer wall (22) of the cage can comprise a plurality of housings shaped as rectangular holes, distributed on the circumference, as yet described for the previous embodiment, and aligned on a plurality of outer circumferences at different distance from the stop (222). In other words, in the hypothesis that there are four wedges (213) on the inner portion (21), on the outer portion (22) there will be provided four housings (223) with the edge aligned at a distance (DI) from the end of the outer portion (22), four housings (224) with the edge aligned at a second distance (D2) from the end of the outer portion (22) and four housings (225) with the edge aligned at a third distance from the end of the outer portion (22).

[0026] In this way, the corresponding wedges (213) provided on the cylinder surface (211) of the inner portion (21) can engage the first row of housings (223), the second (224) or the third one (225). Therefore, the length in axial direction comprised between the two stops (212, 222) is variable, and this allows to use friction rings of different height (31, 32, 33), shown in FIG. 6. The cages assembled with the rings with different height are shown in FIG. 7.

[0027] In case of using rings with such height that the inner portion is moved away from the outer one, there can be used inner (42) or outer (41) spacers. The use of an outer spacer (41) is shown in FIG. 7, where it is shown how one or more of these spacers can be used to lengthen the cylinder wall (221) of the outer portion until it strikes against the inner portion. The use of an inner spacer (42) is the same and it is used to lengthen the cylinder wall of the inner portion (21) until it strikes against the outer portion. Obviously, the inner spacer (42) is hidden from the view in FIG. 7, where the cage is shown assembled.