GB2043432A - Vacuum cleaner - Google Patents

Abstract

A vacuum cleaner has an air duct 7 forming the major part of an airway between suction inlet 5 of the cleaner and impeller housing 8, having an outlet 19 leading to a dust-collecting container (not shown). The airway passes through chamber 11 and the dust-laden air in passing through the chamber is caused to change direction through a right angle between the entrance to the chamber at neck part 10 of the air duct and chamber exit 17 into the impeller housing 8. The change of direction causes heavy objects to drop out of the air stream into a well in the lower part of the chamber 11. Separation is assisted because the chamber 11 forms an expansion chamber through which the air velocity is reduced. End wall 14 opposite the entrance to the chamber at neck 10 is shaped to direct down into the well objects which strike it. Removable trap 16 is provided in the base of the well. <IMAGE>

Description

SPECIFICATION Improvements in vacuum cleaners This invention relates to vacuum cleaners, more particularly but not exclusively of the upright type.

In certain types of upright vacuum cleaners dust and other matter removed by the cleaner from the surface being cleaned pass through the impeller before reaching the dust container. Large or heavy objects picked up by the cleaner can cause damage to the impeller.

Objects such as coins, screws, nails and the like are apt to become jammed between the impeller blades and the impeller housing resulting in bent or broken blades.

An object of the invention is to alleviate impeller damage caused by large or heavy objects by removing such objects from the airstream flowing into the impeller.

The present invention consists in a vacuum cleaner having an airway for dust-laden air and leading from a suction inlet of the cleaner to an impeller and a dust-collecting container on the delivery side of the impeller wherein the airway includes means for inducing a change of direction of the main stream of dust-laden air and the vacuum cleaner comprises a well, below and open to the region of the airway which includes the said means and out of the main stream of dust-laden air, for collecting objects separated from the main stream by the said means.

Due to their inertia large or heavy objects are not turned with the main air stream when its direction is changed and become separated therefrom and fall into the well.

The means for inducing a change of direction of the main stream of air through the airway may be provided by arranging the entrance and exit of a chamber forming part of the airway at a significant angle to one another, for example at right angles. As the air carrying light debris is drawn through the airway by the impeller it readily undergoes the change of direction between the entrance and exit of the chamber without the provision within the chamber of a guiding surface such as a bend conforming to the cross-section of the airway. Such a guiding surface would tend to interfere with the separation of large and heavy objects.

Separation may, in addition, be assisted by forming the chamber as an expansion chamber in the airway at the change of direction and by arranging the means for inducing the change of direction nearer the impeller rather than the suction inlet of the airway so that the momentum acquired by the objects separated is considerable. A surface is preferably provided at or near the change of direction, lying in the path of objects to be separated and which is disposed and shaped to direct separated objects into the well.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which: Figure 1 is a cut-away perspective view of a body part of an upright vacuum cleaner; Figure 2 is a cut-away, partly-sectional view in end elevation of the vacuum cleaner body of Fig. 1; and Figure 3 is a plan view of an air duct component contained within the body.

The body of the upright vacuum cleaner is indicated by the reference 1 and is shown in Fig. 1 with a portion of its casing 2 cut away.

The body 1 is movable on wheels 3 (Fig. 2) over the surface to be cleaned and a powerdriven rotatable brush and/or beater 4 is arranged across the front of the body in an elongated opening 5 in the underside of the body. The axes of the wheels 3 and beater 4 lie parallel to one another and to the major axis of the opening 5 which extends over nearly the full width of the body.

An air duct 7 provides the major part of an airway between the elongated opening 5 and an impeller housing 8. An upward outlet 19 of the impeller housing 8 on the delivery side of the impeller leads to a dust-collecting container (not shown). The airway between the elongated opening 5 and an elongated open end 9 of the air duct 7 is formed by the forward part of the casing 2. From its open end 9 the air duct 7 converges to a neck portion 10 of square cross-section which opens into the upper part of the front of a chamber 11 substantially above floor level.

The chamber 11 has a flat top wall 15, and an outwardly curving back wall 14uextending down almost to the base of the body 1 where it turns sharply downwards. A vertical front wall 1 4a extends from the neck portion 10 to the bottom of the body 1 and is integral with parallel, vertical side walls 12, 13 of the chamber 11 spaced apart by a distance equal to the width of the neck portion 10. The chamber 11 has an open rectangular bottom and the walls 12, 13, 14, 14a fit tightly into a rectangular groove in the moulded base of the body 1. A hole is provided in the base for the reception of a removable trap 16, so that access to the chamber may be gained from the underside of the body 1. The trap 16, instead of being bodily removable, may be hinged to the base.

In the side wall 12 is a circular opening 17 into the bore of a short, tubular extension 18 of the air duct 7 leading to the impeller housing 8. The circular opening 17 is substantially smaller in cross-sectional area than the side wall 12 through which it opens. The neck portion 11 has an internal cross-section which again is smaller than the area of the wall into which it opens, but which is similar to the area of the opening 17. The upper part of the chamber 11 therefore forms an expan sion chamber in the airway which dust-laden air enters in one direction through the neck portion 10 and leaves through the opening 17 in a direction at right angles. This arrangement induces a change of direction of the main stream of dust-laden air passing through the chamber 11. Lighter particles of dust remain in the main-stream and continue through the opening 17 into the impeller housing 8.Because of their greater momentum and inertia, large or heavy particles tend to continue in their entry direction past the opening 17. If their momentum is considerable they strike the end wall 14 opposite the neck portion 10. The end wall 14 is disposed and shaped to direct such separated particles downwards so that they fall into the lower part of the chamber 11 which forms a well 20, out of the main stream of dust-laden air and below the part of the chamber 11 at which the change of direction of the main stream is induced. The reduction in air velocity due to the expansion chamber formed by the upper part of the chamber 11 also tends to cause large or heavy objects to fall out of the air stream. Objects collected in the well 20 are out of the main stream of air flowing through the airway and are unlikely to be picked up again even when the air velocity through the upper part of the chamber 11 increases, for example, when the elongated opening 5 is lifted from the floor. Objects collected can be removed from the well by opening the trap 16.

If desired an aperture with a removable cover may be provided in the wall 13 opposite the opening 17 to enable the bore of the tubular extension and the opening to the impeller housing to be reached and cleared, if either of them should become blocked.

Claims (8)

1. A vacuum cleaner having an airway for dust-laden air and leading from a suction inlet of the cleaner to an impeller and a dustcollecting container on the delivery side of the impeller wherein the airway includes means for inducing a change of direction of the main stream of dust-laden air and the vacuum cleaner comprises a well, below and open to the region of the airway which includes the said means and out of the main stream of dust-laden air, for collecting objects separated from the main stream by the said means.

2. A vacuum cleaner according to Claim 1 wherein the means for inducing a change of direction of the main stream of dust-laden air through the airway comprises a chamber, forming part of the airway, the entrance and exit of the chamber being at an angle to one another.

3. A vacuum cleaner according to Claim 2 wherein the angle is substantially a right angle.

4. A vacuum cleaner according to Claim 2 or Claim 3 wherein the chamber is formed as an expansion chamber in the airway at the change of direction.

5. A vacuum cleaner according to any preceding claim wherein the means for inducing the change of direction is nearer the impeller rather than the suction inlet of the airway.

6. A vacuum cleaner according to any preceding claim wherein the airway converges from the suction inlet to the means for inducing the change of direction.

7. A vacuum cleaner according to any preceding claim wherein a surface is provided at or near the change of direction and lying in the path of objects to be separated, the surface being disposed and shaped to direct separated objects into the well.

8. A vacuum cleaner substantially as described herein with reference to and as illustrated by the accompanying drawings.