GB2421066A

GB2421066A - Vacuum cleaner hose

Info

Publication number: GB2421066A
Application number: GB0520869A
Authority: GB
Inventors: Diane Gibson
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 2004-12-10
Filing date: 2005-10-14
Publication date: 2006-06-14
Also published as: GB0520869D0; GB0427065D0

Abstract

A stretch vacuum cleaner hose 1 has an outer flexible wall 2, preferably of PVC, supported by an inner helical reinforcement member 3. The hose 1 preferably has a natural retracted length and can be lengthened by pulling on one end against the resilience of the reinforcement 3. The weight of the hose 1 is reduced by using a lightweight reinforcement member 3. The reinforcement member 3 comprises a relatively thin metal wire 4, which may be a high tensile strength steel wire, and a relatively thick coating 5 of non-metal, preferably of plastics. The ratio of the volume of metal wire 4 to the non-metal coating 5 per unit length in the reinforcement 3 is less than about 0.6, preferably about 0.21. Preferably, the metal wire 4 has a diameter of 0.71 mm, and the overall diameter of the reinforcement 3, including the non-metal coating 5, is 1.66 mm.

Description

VACUUM CLEANER HOSES

This invention relates to vacuum cleaner hoses.

Vacuum cleaner hoses usually comprise a flexible tubular wall of plastics material and a supporting helix, either inside or outside the plastics wall. In some hoses the supporting helix is resilient along the axis of the hose and has a natural contracted length so that the hose has a natural, relatively short length and can be stretched to a longer length by pulling on the end of the hose. In other hoses the helix may have a natural, extended length so that the hose extends to its full length when released and can be compressed to a shorter length after use, for storage, by manually pushing the free end of the hose towards its opposite end.

Alternatively, such as described in W003/024294, the hose may be retracted by blocking the free end of the hose while the vacuum cleaner is on, so as to create a reduced pressure within the hose sufficient to cause it to retract.

The supporting helix or reinforcement of the hose takes the form of a metal wire with a thin plastics coating. The coating protects the metal wire from corrosion, enables the wire to be bonded to the wall and improves the appearance of the hose where the wire extends externally. Typically, the wire is of steel and has a diameter of 1.22mm, the plastics coating giving an overall diameter of 1.66mm. The plastics coating is, therefore, a relatively minor part of the supporting helix as a whole, the ratio of the volume of metal to plastics per unit length being about 1.17.

The helical reinforcement contributes significantly to the weight of the hose and also contributes to the overall weight of the vacuum cleaner. This makes the hose and vacuum cleaner more difficult to use than would be the case if it were lighter. A greater weight also makes a retractable hose more difficult to retract by suction.

It is an object of the present invention to provide an alternative vacuum cleaner hose.

According to the present invention there is provided a vacuum cleaner hose of the kind comprising a tubular wall and a helical reinforcement member having a metal wire and an outer non-metal layer, the ratio of the volume of metal to non-metal per unit length in the reinforcement member being less than about 0.6.

Preferably the ratio of the volume of metal to non-metal per unit length is not more than 0.3 and may be about 0.21. The wire is preferably of circular section with a diameter of substantially 0.71mm, the overall diameter of the reinforcement member being 1.66mm.

Preferably the non-metal layer is of a plastics material, such as a PVC. The tubular wall may be of the same material as the non-metal layer. The helical reinforcement member preferably extends internally inside the tubular wall. The metal wire is preferably of a high tensile strength steel. The hose may have a natural contracted length and can be extended to a greater length by applying a force to extend the hose against the resilience of the reinforcement member.

A vacuum cleaner hose according to the present invention will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a sectional view along a part of the length of the hose; and Figure 2 is an enlarged cross-sectional view through the reinforcing helix.

The hose 1 comprises a flexible wall 2, an inner helical reinforcing member 3 and conventional couplings (not shown) at either end. The wall 2 is of a plastics material such as PVC. The reinforcing member 3 comprises an inner steel wire 4 and an outer coated layer 5 of a non-metal, such as a plastics material. The wire 4 and the reinforcing member 3 both have a circular section. Preferably the coating 5 and the wall 2 are of the same material so that they can be bonded securely with one another, such as by heat or solvent. The hose I is of the stretch kind where it has a natural, short, contracted length but can be pulled to a longer length against the resilience of the reinforcement member 3 and returns to its shorter length when released. The hose 1 may be made in any conventional way, such as, by winding the reinforcement member 3 onto a mandrel and wrapping a strip of the wall material 2 on top of the reinforcement in overlapping layers.

The overall diameter D of the reinforcing member 3 is 1.66mm, which is the same as in conventional hoses. The reinforcing member 3, however, differs from conventional ones in that the internal metal wire 4 has a much smaller diameter d. Preferably, the diameter d of the wire 4 is 0.7 1mm and the thickness t of the PVC coating 5 is 0.48mm. The volume per unit length of the steel wire 4 is, therefore, 0.40mm2 and the volume per unit length of the plastics coating 5 is 1.79mm2. This gives a ratio of the volume per unit length of metal to plastics of 0.22, which is considerably less than in conventional reinforcement hoses where the ratio is 1.17. By making the reinforcement member predominantly non-metal instead of predominantly metal, as in previous hoses, the weight of the reinforcement member can be reduced to 50% that of conventional reinforcement members. This results in a substantial reduction of the overall weight of the hose 2 compared with a conventional hose of the same size because the reinforcement member contributes a major part of the weight of the hose.

In order to ensure that the reinforcement member 3 still provides adequate strength against crushing of the hose 2 and sufficient resilience to retract the hose when it is released from its stretched state, the steel wire 4 has a higher tensile strength than the wire used in conventional hoses. The wire 4 preferably has a tensile strength of between about 2000 and 2600MPa and is preferably towards the higher end of this range, which compares with the tensile strength of wire used in conventional hoses of between about 1600 and 1800MPa.

It might be possible to use wires of even smaller cross-sections, such as having a diameter of 0.51mm, which would give an even greater weight saving of about 60% in reinforcement members of the same external diameter. The problem with such thin wires, however, is that it is not clear that they could provide sufficient strength to the hose for normal use. There might, however, be some special applications where a very lightweight hose was needed that did not require high strength. Larger gauge wires could be used with a consequent loss in the weight saving. There might still be advantages in hoses having a reinforcement element where the ratio of the volume per unit length of the metal to the nonmetal was up to about 0.6.

It will be appreciated that the wire and the reinforcement member need not be circular in section, they could, for example be oval or rectangular. The outer layer of the reinforcement member need not be of a plastics material, providing it was of a non-metal having a lower density than the metal wire. The outer layer need not necessarily be applied as a coating on the wire, it could, for example, be a preformed sleeve into which the wire was inserted. The reinforcement member need not be on the inside of the hose but could extend externally. The hose need not have a stretch characteristic but could be of the conventional kind having a fixed length, or it could be of the retractable kind having a natural extended length and retractable for storage to a shorter length by manual compression or by a reduced pressure within the hose created by the vacuum cleaner.

Claims

1. A vacuum cleaner hose of the kind comprising a tubular wall and a helical reinforcement member having a metal wire and an outer non-metal layer, wherein the ratio of the volume of metal to non-metal per unit length in the reinforcement member is less than about 0.6.

2. A vacuum cleaner hose according to Claim 1, wherein the ratio of the volume of metal to non-metal per unit length is not more than 0.3.

3. A vacuum cleaner hose according to Claim 2, wherein the ratio is about 0.21.

4. A vacuum cleaner hose according to any one of the preceding claims, wherein the wire has a circular section.

5. A vacuum cleaner hose according to Claim 4, wherein the diameter of the wire is substantially 0.71mm.

6. A vacuum cleaner hose according to any one of the preceding claims, wherein the overall diameter of the reinforcement member is substantially 1.66mm.

7. A vacuum cleaner hose according to any one of the preceding claims, wherein the non-metal layer is of a plastics material.

8. A vacuum cleaner hose according to Claim 7, wherein the plastics material is a PVC.

9. A vacuum cleaner hose according to any one of the preceding claims, wherein the tubular wall is of the same material as the non-metal layer.

10. A vacuum cleaner hose according to any one of the preceding claims, wherein the helical reinforcement member extends internally inside the tubular wall,

11. A vacuum cleaner hose according to any one of the preceding claims, wherein metal wire is of a high tensile strength steel.

12. A vacuum cleaner hose according to any one of the preceding claims, wherein the hose has a natural contracted length and can be extended to a greater length by applying a force to extend the hose against the resilience of the reinforcement member.

13. A vacuum cleaner hose substantially as hereinbefore described with reference to the accompanying drawing.

14. Any novel and inventive feature or combination of features as hereinbefore described.