GB2217733A

GB2217733A - Laundry drum for a washing machine

Info

Publication number: GB2217733A
Application number: GB8907735A
Authority: GB
Inventors: Lothar Heinzel
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-04-28
Filing date: 1989-04-06
Publication date: 1989-11-01
Anticipated expiration: 2009-04-06
Also published as: HK92795A; TR25582A; IT1229651B; DE8817044U1; IT8920249A0; GB2217733B; ES2012706A6; DE3814426A1; GB8907735D0

Description

il 1 1 LAUNDRY DRUM FOR A WASHING MACHINE 2217733 The present invention

relates to a laundry drum for a washing machine.

In the case of a laundry drum of the kind known from DE-05 14 60 840, the shell of the drum consists of a pre-punched sheet metal part which is bent in a subsequent production step and swaged to the drum base. The entraining members can be inserted into the sheet metal of the drum shell in likewise known manner. Finally, the spider is secured by screws to the drum base. There remains a need, however, for a drum which is securely held together by only a few screw elements, so that alternating vibratory forces during spinning of the drum do not lead to loosening of the connections. Moreover, simple assembly is also desirable.

According to the present invention there is provided a laundry drum for a washing machine, comprising a drum shell, a drum base, a plurality of elongate hollow entraining members arranged at the inner circumference of the shell and each provided with a flange at an end thereof adjacent to the drum base, a respective nut which is arranged in each entraining member and which has a cross-sectional profile substantially corresponding at least in part with that of the member, and a respective bolt threadedly engaged in each nut to clamp therebetween the flange of the associated entraining member, a portion of the drum base and mounting means for the drum.

In a preferred embodiment, the drum comprises hollow roof-shaped entraining members inserted in the drum shell, the drum base being fastened to a drum spider by means of threaded bolts at the level of the entraining members. A nut matched to the internal profile of each entraining member is laid into the member, which has at least one partial gable surface or flange,'and the threaded bolt and the nut clamp i t - 2 therebetween the flange, the drum base and the spider at the same time. By this means a non-yielding connection, which cannot loosen even on the occurrence of alternating forces, may be provided between the bearing surface of the bolt head and the nut. The nut is non- rotatable because of its profile shape. Since the nut can easily be inserted into the interior of the entraining member, which for this purpose can have a specia 1 chamber, the nut is kept captive for the assembly operation. The individual parts can therefore be_easily assembled without several parts having to be held at the same time.

Production is further facilitated if each of the entraining members, at its contact surface towards the drum shell, has thrust detent elements which engage into keyhole slots shaped to fit therewith. Accordingly, the entraining.members with the inserted nuts can initially be inserted into the drum shell, and the spider need merely be held in front of thread- ed bores in the nuts for assembly.

In order that nuts which flave been placed in the shell before insertion of the entraining member do not fall out of the members, each member can partially enclose the respective nut by its contact surface towards the drum shell. The nut, together with a securing screw which preferably eftends at right angles to the bolt, then secures the enclosing part of the contact surface. Thus, after insertion of the entraining members, each entraining member is held by a securing screw in the installed position before the associated bolt is screwed in.

Advantageously, the threaded bore for the bolt eRtends centrally in the nut, while the threaded bore for the securing screw eRtends past the bolt and substantially perpendicularly thereto. Through this arrangement of threaded bores, the nut can be kept flat without the 2! A 9 1 length of the bores having to be restricted.

If so desired for the purpose of ensuring the strength of the bore for the bolt, the bore can be formed at least partially in a sleeve protrusion of the nut.

Advantageously, the threaded bore for the securing screw has a depression and the nut is widened in lip-shape in the region of the depression. Such a depression, together with a correspondingly shaped projection of the shell of the drum, can provide a defined seating of the entraining member. In order that the nut need not be shaped more ektensively, it is widened in lip-shape only in the region of the depression.

Embodiments of the present invention will now be more particularly described by way of 6ample with reference to the accomDanying drawings, in which:

Fig. 1 is an elevation of part of an entraining member in a first laundry drum embodying the invention; Fi9. 2 is a cross-section,along the line II-II of Fig. 1, of the entraining member; Figs. 3a, b and c are views of a detent element (detached) of an entraining member and an associated keyhole slot in the shell of the drum, Fig. 3c showing the detent element in section; Fig. 4 is an end view of a nut insertable into the entraining member; Fig. 5 is a sectional view,along the line M in Fig. 4, of the nut inserted into the entraining member, together with a securing screw and threaded bolt at the drum base and at a mounting spider; f 1; Fig. 6 is a view of Dart of the drum base with the sDider fastened thereto; Fig. 7 is a view of part of the shell of asecond drum, showing keyhole slots, embodying the invention; Fig. 8 is a cross-section of an entraining member in the second drum; Fig. 9 is a longitudinal section of the entraining member of Fig. 8; Fig. 10 is an end view of a nut for the entraining member of Fig. 8; and Fig. 11 is a side elevation of the nut.

Referring now to the drawings, there is shown in Fig. 1 an entraining member 1 which is made of plastics material and has thrust detent elements 2, which can be shaped as shown in Fig. 3 and engage into keyhole slots 5 in the shell 4 of a laundry drum. The entraining member is thereby retained at the drum shell 10. The entraining member is substantially roof-shaped and, at one of its ends, has a collar or flange 3 which bears against the base 11 of the drum. A plurality of such entraining members, for entraining laundry, are spaced around the inner circumference of the shell 4 of the drum.

According to Fig. 2, the detent elements 2 are moulded on the upper surfaces of the entraining member limbs, which are the contact surfaces towards the drum shell. For the insertion of the detent elements 2 into the keyhole slots 5, these limbs are pressed together and then relieved after introduction of the elements 2 into-the slots.

Thereby, the entraining members are fastened at the drum shell.

Fig. 3 shows the keyhold slots 5 in the drum shell 4. Each slot is stepped and possesses a recess 51. On insertion of the entraining :1, A 1 1 member, the head 2' on the neck 6 of the detent element 2 protrudes through the slot 5. On relief of the stress on the limbs of the entrain ing member, the detent elements 2 detent into the associated recesses 5' of the slots 5. The entraining member is now fastened to the drum shell 5 and eRtends over the entire depth of the drum (not illustrated). Advantageously sig to eight detent elements and associated keyhole slots 5 are distributed in two rows over this depth.

Each entraining member also receives a nut 7 which, as shown in Fig. 4, is profiled to be substantially triangular and thereby adapts itself to the internal profile of the entraining member. The nut serves for the fastening of the entraining member 1 and of a spider 14 to the drum base. For this purpose, a threaded bore 9, into which a threaded bolt 15 is screwed, extends through the nut in direction of the longitudinal axis of the entraining member. A further threaded bore 8 extends perpendicularly to the bore 9 and passes by it. The bore 8 receives ascrew 13 which serves for fastening of the entraining member to the drum shell.

According to Fig. 5, the drum shell 10 is connected with the drum bdse 11 by way of a beaded seam 12. Before fastening each entraining member 1 to the drum shell 10, the respective nut 7 is placed in the cavity of the member. After the entraining member has been disposed - in its prescribed installed position, it is retained by.a respective countersunk screw 13 at the drum shell. The spider 14 can then be fastened to the drum base 11 by means of the bolt 15 screwed into the nut 7. In that case, the drum base 11 and the spider 14 are firmly clamped between the nut 7 and the head of the bolt 15. A recess, which has a somewhat lower depth than the thickness of the flange 3, is moulded on at the appropriate surface-of the nut for retention of the flange 3, which is formed from the plastics material of the entraining member. The nut can set down firmly on the drum base, with the flange 3 being squeezed in place, on tightening of the bolt 15. 5 According to Fig. 6, the securing screw 13 is arranged centrally in the nut 7, whereagainst the bolt 15 and therefore also the respective arm of the spider 14 is located ecentrically relative to the nut 7. The described constructional features can be altered in a variety of ways. For example, the detent elements 2 can be of a different shape.

1he nut 7, too, can be shaped to match the shape of the entraining members.

Figs. 7 to 11 show another embodiment of the invention. In this embodiment, the keyhole slots 5 in the shell 4 of the drum are elongated and each have a narrower prolongation 16 in the longitudinal direction. Each slot is about twice as long as the length of the associated detent elements 2. The entraining members, however, are shorter by about the amount of this length than the clear width between the bases of the drum. For insertion of the entr-aining members, the detent elements 2 are guided through the wide parts of the keyhole slots 5 and then displaced in direction towards the longitudinal prolongations 16. Since the detent elements 2 are undercut, their necks 6 can be pushed into the prolongations 16 of the slots 5 so that the heads of the detent elements 2 li above the respective sheet metal projection in the drum shell. The entraining members are thereby secured against dropping out in this position.

The necks 6 of the detent elements 2 are, as shown in Fig. 8, integral moulded parts of the limbs 11 of the entraining members. A plurality of reinforcing ribs 17, of which the rib closest to the flange 3 has a recess 18, is formed in each entraining member. The :5 1 i 1 ribs prevent the limbs 11 of the entraining member from being pressed together.

The longitudinal section through the entraining member in Fig. 9 shows that the detent elements 2 project above the upper edge 23 of the entraining member by about the thickness of the sheet metal of the drum shell, i.e. the neck 6 is as long as the wall of the shell is thick. -As soon as the entraining member is tightened against the drum base, the head of each detent element 2 engages over the outer circumference of the shell and holds the entraining member against the shell. The nut 7 was previously placed in the chamber 19, which is bounded by a rib 17, by the flange 3 and by the limbs V.

The nut 7 is illustrated in Figs. 10 and 11. Its end face 20 has a setback step 24, into which the flange 3 engages when the nut has been placed in position. With the entraining member inserted, the end face 20 lies directly against the drum base 11. The threaded bore 9 for the threaded bolt is arranged centrally in the nut in this embodiment, whereagainst the threaded bore 8 for the securing screw is arranged eccentrically and eftends past the bore 9 perpendicularly thereto. The bore 9 is longer than the basic depth of the nut and is therefore partly formed in a sleeve prolongation 21, so that sufficient thread length is present for the required strength. This sleeve prolongation engages into the recess 18 of the rib 17 bounding the chamber 19. The opening of the threaded bore 9 has a guide deflection in order that the bolt can be accurately guided therein during assembly and cannot cant over while being screwed in.

The nut is widened by a lip 22 in the region of a depression at the threaded bore 8 of the securing screw. The part of the depression that projects beyond the main boundary of the nut is formed in this lip.

Claims

- 8 CLAIMS 1. A laundry drum for a washing machine, comprising a drum

shell, a drum base, a plurality of elongate hollow entraining members arranged at the inner circumference o f the shell and each provided with a flange at an end thereof adjacent to the drum base, a respective nut which is arranged in each entraining member and which has a cross-sectional profile substantially corresponding at least in part with that of the member, and a respective bolt threadedly engaged in each nut to clamp therebetween- the flange of the associated entraining member, a portion of the drum base and mounting means for the drum.
2. A drum as claimed in claim 1, wherein each of the entraining members is provided at a side thereof contacting the shell with detent elements engaged in shaped slots in the shell.
3. A drum as claime-d in either claim 1 or claim 2, wherein each entrain15, ing member partially encloses t-he respective nut at a side of the member contacting the shell and the enclosing part of the member is secured by the nut and by a respective securing screw which is threadedly engaged in the nut and the ais of which is substantially perpendicular to the associated bolt.
4. A drum as claimed in claim 3, wherein each bolt extends along a central aial-plane of the respective entraining member and the associated securing screw eRtends to one side of the bolt.
5. A drum as claimed in any one of the preceding claims, wherein each bolt eRtends in a sleeve protrusion of the respective nut.

r.
6. A drum as claimed in either claim 3 or claim 4, wherein each of the nuts is provided with a depression at the entrance of a threaded bore for the respective securing screw and with a lip-shaped enlargement in the region of the depression.
7. A laundry drum substantially as fiereinbefore described with reference to Figs. 1 to 6 of the accompanying drawings.
8. A laundry drum substantially as hereinbefore described with reference to Figs. 7 to 11 of the accompanying drawings.
9. A washing machine comprising a laundry drum as claimed in any one of the preceding claims.

1 PubUshed 1989 at The Patent Offioe. State House, 6671 High Holborn, London WC1R 47?. Purther 0008B MVbe obZ ad znT e_ nt X tOCIMIWeB Itcl, St M&17 CM, Kant, C;on, 1/87 Was Brancb, St M817 C-dv, CI'Tir4gwn, Kent BR5 3BD.Pr1nted by MultiPle &n fro h PZteOMoe.