WO2008154682A1

WO2008154682A1 - An apparatus for use in gathering debris by applying a vacuum

Info

Publication number: WO2008154682A1
Application number: PCT/AU2008/000879
Authority: WO
Inventors: Paul Gripske
Original assignee: Roy Gripske & Sons Pty Ltd
Priority date: 2007-06-18
Filing date: 2008-06-18
Publication date: 2008-12-24
Also published as: AU2008265500A1

Abstract

A portable vacuum apparatus for use in gathering up pieces of solid matter is disclosed. The vacuum apparatus (1) includes a housing (7) defining an inlet (31), an outlet (33) and an airstream flow path extending from the inlet (31) to the outlet (33). An impeller (3) is mounted in the airstream flow path of the housing (7). Further, a rotatable material separator (13) is also positioned in said airstream flow path of the housing (7), upstream of the impeller. The rotatable material separator (13) helps to remove pieces of solid matter from the airstream. An improved screen member (13) comprising a flattened member having two major surfaces defining a central hub region and a screen region radially outward of the hub region. The hub region defines an opening through which the securing bolt (11) passes. The screen region defines a plurality of screen openings (23) therein for screening out larger and/or higher density materials. A method for gathering up pieces of solid matter with the apparatus is also disclosed.

Description

AN APPARATUS FOR USE IN GATHERING DEBRIS BY APPLYING A VACUUM

FIELD OF THE INVENTION

This invention relates to a portable apparatus for use in gathering up pieces of solid matter. The invention also extends to a screen member for use in an apparatus for gathering up pieces of solid matter. The invention also extends to a method of gathering up pieces of solid matter.

This invention relates particularly to an apparatus for gathering up pieces of solid matter that include garbage, litter, garden waste and debris and the like. In particular, it relates to a portable vacuum or blower-vacuum unit. It will therefore be convenient to hereinafter describe the invention with reference to this example application. However at the same time it is to be understood that the invention is capable of broader application.

BACKGROUND TO THE INVENTION An apparatus that includes a blower for directing debris is known. In particular a portable blower that blows air out of a wand is known. The apparatus can be used to blow pieces of solid debris including general garden waste, dirt and dust and litter and garbage in a certain direction to assist in cleaning up the solid debris. The portable blower is like a pneumatic broom that can be used to move the debris around. Further, a vacuum apparatus for use in collecting debris by applying a vacuum is also known. The vacuum apparatus comprises a housing defining an inlet and an outlet and a flow passage passing from the inlet to the outlet. A centrifugal impeller is positioned within the flow passage and rotatably connected to a power source that causes the impeller to rotate. The power source is typically an internal combustion engine or an electric power driven motor (which may utilise a portable electrical supply such as a battery). The apparatus further includes an inlet conduit or wand having a flow passage that is mounted on the housing such that the flow passage is in communication with the flow passage in the housing. The apparatus further includes a collector defining a collection chamber that is mounted on the housing over the outlet such that the flow passage of the housing is in flow communication with the collection chamber. The collector has at least a region that permits air to pass therethrough to vent it from the apparatus. Typically, the collector might comprise a bag made of fabric that is permeable to air but that resists the passage of particles therethrough.

In such apparatus, the housing may be able to be selectively connected with either a suction circuit so as to operate as a vacuum unit or alternatively a discharge circuit communicating with the outlet so as to operate as an air blower. This combined blower/vacuum apparatus can therefore selectively be used either to suck debris or to blow and direct or gather debris. This dual functionality is useful because it obviates the need for a user to have a separate vacuum apparatus and a blower apparatus. The blower vacuum may be converted from vacuum mode to blower mode by, e.g. disconnecting the vacuum cowling from the power unit and by connecting an alternative air conduit to the outlet. The air conduits may be connected to the suction and discharge circuits by any suitable means. For e.g., this may be means of co-operating flanges on the blower and the air conduit which hold the air conduit to the blower at the two respective locations, by way of a screw in or snap fit arrangement or by some other form of coupling arrangement.

In use, rotation of the centrifugal impeller draws air and associated debris into the inlet through the inlet conduit. This air and debris then passes through the impeller before being discharged into the collection chamber through the outlet. The collector can be emptied from time to time to dispose of the debris collected in the collection chamber.

The vacuum apparatus described above sucks up debris which is then disposed of by emptying the collector. This is useful because otherwise the recovery of debris including dust, sand, stones, soil, leaves, twigs, sticks and branches can be very time consuming and require a large physical effort on the part of the user. However, a shortcoming of existing forms of vacuum apparatus of the type described is that it draws an air stream laden with materials of different sizes and different densities through a high speed centrifugal impeller. Some materials collide with the impeller as it rotates. Over time, this causes damage to the impeller. Other materials, particularly softer materials such as leaves and paper can catch on the impeller, and impede its rotation. If these materials become tangled in the impeller and housing, this can cause sudden failure of the impeller. The impact of the materials against the impeller leads to high levels of wear of the impeller and consequently a short service life thereof. Yet further, if oversize materials, e.g. bottles and cans, are drawn into the inlet by the applied vacuum they may be unable to pass through the impeller and may become stuck in the impeller or its housing. This may cause the impeller or the impeller housing to crack or to be otherwise damaged. Further, if an oversize particle becomes stuck in the impeller housing upstream of the impeller it will significantly impede the efficient operation of the impeller. This will also generate additional noise, and vibration and rattling.

Clearly, it would be advantageous if a vacuum apparatus could be devised that was less prone to the problems described above caused by larger and higher density materials. In particular, it would be advantageous if a more heavy duty vacuum apparatus could be devised with strong suction able to handle larger and heavier materials which had a reasonable service life and was not prone to failure when oversize materials entered the inlet. By application of a strong vacuum, a greater range and concentration of debris, particularly articles of larger size and density, can be collected. Further, it would be advantageous if the apparatus overcame these problems without a substantial loss of suction in the vacuum apparatus, it being recognised that the strength of the vacuum is an important factor in the overall collection efficacy of the apparatus,

SUMMARY OF THE INVENTION

According to one aspect of this invention there is provided a portable vacuum apparatus for use in gathering pieces of solid matter, including: a housing defining an inlet, an outlet, and an airstream flow path extending from the inlet to the outlet; an impeller mounted in the airstream flow path of the housing carrying small pieces of solid matter along the flow passage; and a rotatable material separator that is positioned in said airstream flow path of the housing, upstream of the impeller, for removing at least some of the pieces of solid matter from the air stream entering the housing. In this specification, the term vacuum shall be interpreted broadly and shall include a body or stream of air at a pressure that is lower than atmospheric pressure. As such, it causes a suction effect when exposed to air at atmospheric pressure. The term vacuum shall also be taken to include a partial vacuum.

In this specification, the term pieces of solid matter shall be interpreted broadly and shall include but not be limited to a wide range of solid matter including general debris, solid rubbish, solid garden waste and solid litter. The above may, for example, include paper, packets, cartons, cans and bottles made of plastic and glass and aluminium. It also includes garden waste and debris. For example, such waste might include leaves, twigs, branches, leaves, stones and soil. In particular, it includes rubbish, litter, garbage, garden waste and debris that is collected and disposed of to clean up gardens, parks, other open areas and public spaces, streets, and of the type found in stadiums after an event. The articles of solid matter may also include solid articles that pose a disposal hazard, for example, syringes, needles, razor blades and other "sharps". The centrifugal impeller may be a high speed impeller having a high rotational speed to generate the appropriate suction in the flow passage.

The diameter and other dimensions of the impeller will be a function of the size and power of the engine used, and will thus vary over a wide range. In some forms, the impeller may have a diameter of 170mm-220mm, e.g. 190mm-200mm.

The airstream may flow through the volute form or flow passage of the impeller housing with a volumetric flow rate sufficient to generate the appropriate vacuum.

The rotatable material separator may rotate about an axis parallel to the longitudinal axis of the airstream flow path. The axis of rotation of the rotatable material separator may be substantially parallel to the rotational axis of the centrifugal impeller, e.g. the rotational axis of the material separator may be co-axial with that of the centrifugal impeller. The material separator may rotate in the same direction as the direction of rotation of the centrifugal impeller. Further, the rotatable material separator may be mounted on the impeller and may rotate in the same direction and at the same speed as the impeller.

The material separator may be a screen that has a plurality of screen openings dimensioned to prevent the passage of materials entrained within the airstream, on the basis of size and/or density. The material separator may also include sharpened cutting edges to cut low density debris into particle sizes capable of passage through the screen openings, and the apertures between the blades of the impeller.

The maximum dimension of all screen openings will be controlled by the minimum pitch dimension between the fins of the impeller such that no debris of a ruling size greater than the minimum pitch of the impeller fins is able to pass through the screen. In some forms, the screen openings may have a length and width that does not exceed 30mm. In some forms, the length and width of the screen openings do not exceed 25mm, and the length and width of the openings may be in the range of 15mm to 25mm. The length of some of the openings may be broadly of the same order of magnitude as their width.

The apparatus may include an upstream material collector for collecting the articles of solid matter removed by the upstream material separator that is positioned adjacent thereto. The upstream collector may take a number of forms but is required to be constructed of a material that is not air permeable and of suitable strength to handle strong suction and the weight of larger and higher density debris. The apparatus may also include a downstream material collector that is positioned downstream of the impeller for collecting the articles of solid matter debris that have passed through the impeller.

Thus, an airstream laden with debris is drawn into the inlet by the impeller. Some of the materials in the airstream are separated from the airstream by gravity and / or by the upstream material separator before they reach the impeller. These materials then fall by gravity from the upstream material separator into the upstream collector where they can be collected and disposed of. These materials are typically those which are larger and of greater density in the airstream. The remaining materials, i.e. the materials not removed by the upstream material separator then pass through the impeller and into the downstream collector from where they can be disposed of. The air from the airstream passes out of the downstream collector and into the environment.

The flow path defined by the housing may have an upstream region of increased diameter upstream of the screen and proximate thereto. This causes a decrease in the velocity of the airstream in the upstream region and as a result larger and heavier materials may fall out of the upstream stream before they actually reach the screen. That is, some materials may fall by gravity into the upstream collector before they reach the screen.

The screen may be substantially planar and the screen may have a substantially circular configuration, e.g. in outline. In some forms, the screen may have a diameter of 120mm to 160mm, e.g. 130-150mm, say about 140mm. In other forms, the screen may have a smaller diameter, e.g. 100mm. Thus the diameter of the screen may be substantially less than the diameter of the impeller. The screen may be constructed of metal, a plastics material such as polyurethane or any other material of suitable strength typically used for this type of purpose. The centrifugal impeller may be rotatably mounted on the housing by means of a shaft. The impeller may be fixedly mounted on the shaft, and the shaft may be rotatably mounted on the housing.

Conveniently, the screen may be mounted on the same axis as the centrifugal impeller, and securely attached to it, and thus the screen and impeller may rotate together. That is, the screen rotates in the same direction and may also rotate at the same speed as the impeller. In an alternative form of the invention, the screen may rotate in the same direction but at a different speed to the impeller. The screen may be mounted on a shaft immediately in front of the impeller, e.g. so that they are closely adjacent to each other. In one form of the invention, the screen may define at least one elongate aperture having a longitudinal edge extending in a radial direction from a central region of the screen to an edge region. The longitudinal edge of the aperture may be tapered in section so as to form a sharp edge. The screen may include at least one blade which is designed to cut and also deflect debris away from the impeller. The blade may be formed by one of the longitudinal edges of the elongate aperture. In particular, the blade will be formed by the leading edge of the aperture as the screen rotates.

In a preferred form of the invention, the screen may define at least two blades each extending from the central region radially out to the circumferential edge region. The blades may be aligned relative to each other so as to extend diametrically across a diameter of the screen. Put another way, when viewed together they extend in a straight line across a diameter of the screen.

In an alternative form of the invention, instead of having a rotating screen, the upstream material separator is a screen which has at least one rotating blade with at least one cutting edge positioned in series with the screen.

In one form of the invention, the blade may be positioned upstream of the screen e.g. adjacent to and upstream of the screen. This operates to cut softer material and also assists in diverting larger and heavier materials into the upstream material separator.

In an alternative form of the invention, the blade may be positioned downstream of the screen, e.g. adjacent to and downstream of the screen. The blade may be sandwiched between the centrifugal impeller and the screen.

The rotating blade may be fixedly mounted on a shaft and said shaft may be the same shaft that is used to rotate the impeller at high speed.

The blade may comprise at least two blade elements, each extending radially out from the axis of rotation to a free end. The free ends may be positioned radially adjacent the circumferential edge of the centrifugal impeller.

The upstream collector may be positioned vertically below the screen and adjacent the screen e.g. in a longitudinal direction, and upstream thereof, so that materials deflected by the screen and blade fall into the upstream collector under the influence of gravity.

The housing may be made of unitary construction.

The upstream collector may form part of the housing. The upstream collector may also be unitarily formed with the rest of the housing. The upstream collector may be sized to receive a suitable amount of solid matter from the upstream material separator, it being recognised that it should not have to be emptied too frequently.

In one form of the invention, the upstream collector may be releasably attached to the remainder of the housing. In this form the collector can be detached from the remainder of the housing to allow the user to conveniently dispose of debris collected therein.

In another form of the invention, the upstream collector may include a discharge opening through which debris collected therein can be discharged from the collector.

The upstream collector may have solid walls, e.g. that are not air permeable. Further, the walls may be rigid and may be formed from the same material as the housing.

The downstream collector may comprise a bag of air permeable material that is releasably attached to the housing and positioned such that the outlet opens into the collector. Alternatively, the downstream collector may be provided with a discharge opening through which debris collected therein can be discharged. The outlet may extend transverse to the axis of rotation of the impeller.

Specifically, the outlet may extend tangentially away from the circumference of the centrifugal impeller.

The housing may include releasable engagement formations and the downstream collector may include complementary releasable engagement formations for releasably coupling the collector to the housing.

The apparatus may further include an inlet conduit or wand mounted on the housing over the inlet thereof and extending outwardly away from the housing to a free end thereof. The inlet conduit may be releasably mounted to the housing, e.g. by releasable engagement formations. Preferably, the inlet conduit is one integrally formed piece. However, it may be comprised of one or more pipes, tubes, or a hose and/or be used with an extension fitting. Preferably, the inlet conduit is a pipe or tube of a plastic material which is lightweight but also of suitable strength, and may be of rigid or flexible construction.

The apparatus may further include one or more handle formations for enabling a user to hold the apparatus. The handle formations may be unitarily formed with the rest of the housing. The apparatus may further include a strap, e.g. for hanging the apparatus from the shoulder of a user for ease of use. The apparatus may further include a sealing means which forms a seal around the periphery of the upstream collector when the upstream collector is attached to the apparatus.

The apparatus may also be capable of being operated in either vacuum or blower mode and therefore be used selectively to either suck debris or to blow and gather debris.

The apparatus may be converted from vacuum mode to blower mode e.g. by disconnecting the vacuum cowling from the power unit and by connecting an alternative air conduit (not shown) to the air outlet or discharge port. The air conduits may be connected to the suction and discharge circuits by any suitable means. This may be by way of complementary releasable engagement formations.

The blower/vacuum unit may also optionally be provided with a vacuum release valve. In the event that debris or other unintended items become clogged at a point in the suction circuit. The release valve enables the suction circuit to be quickly released, thereby preventing potential damage to the motor or impeller housing. This is also an added safety feature for the user.

The apparatus may also optionally include a safety grille to be fitted over the impeller and screen.

A metal plate may optionally be positioned to protect the inner face of the scroll case so as to provide a dust seal. This also acts to protect the moulded plastic face of the scroll case from overheating due to friction from debris moving at high speed in the airstream flow path.

According to another aspect of this invention, there is provided a screen for mounting to a vacuum apparatus, the screen comprising: a flattened member having two major surfaces defining a central hub region and a screen region radially outward of the hub region, the screen region defining a plurality of screen openings therein for screening out materials and permitting some materials to pass therethrough, and the hub region being for mounting the member to a shaft for rotating the screen in use.

The flattened member may be of substantially circular configuration and the major surfaces of the flattened member may each be substantially planar. The flattened member may also define a circumferentially outer region towards the circumferential edge of the member radially outward of the screen region.

The hub region of the member may define an opening through which a rotatable shaft is passed and to which the member can be mounted in use. The screen region may define a plurality of screen openings. At least some of the screen openings may have a length that is comparable to their width. Further the openings may have four sides although the opposed sides thereof may not necessarily be parallel to each other. The screen region may define at least 10 screen openings therein, e.g. 10 screen openings to 25 screen openings.

The screen may further include at least one blade for cutting or chipping softer materials.

In one form, the screen may define at least one elongate aperture having a longitudinal edge extending in a radial direction from the central region of the screen to the edge region. The longitudinal edge of the aperture may be tapered in section so as to form a sharp edge. A blade may be formed by a longitudinal edge of said elongate aperture. In particular, the blade will be formed by the leading edge of the aperture as the screen rotates. The upstream material separator may have two blades each extending from the central region radially out to the circumferential edge region. The two blades may be aligned relative to each other so as to extend diametrically across a diameter of the screen. Put another way, when viewed together they extend in a straight line across a diameter of the screen. The screen member may be formed from sheet steel.

According to another aspect of this invention, there is provided a method of gathering up pieces of solid matter, the method comprising the following steps: providing a portable vacuum apparatus including: a housing defining an inlet, an outlet, and an airstream flow path extending from the inlet to the outlet, an impeller mounted in the airstream flow path of the housing; a rotatable material separator in said airstream flow path of the housing, upstream of the impeller; applying a vacuum to the housing; drawing an airstream with entrained pieces of solid matter through the housing; separating out some of the pieces of solid matter drawn into the housing by means of the rotatable material separator; and passing the airstream and the remainder of the entrained pieces of solid matter through the impeller and then discharging it through an outlet.

The step of separating some of the pieces of solid material may comprise separating out materials by means of openings in the rotatable material separator dimensioned to prevent the passage of materials entrained within the airstream on the basis of size and / or density.

The method may include collecting said pieces of solid matter that are separated out of the airstream upstream of the impeller. This step of collecting may comprise collecting the pieces of solid matter in an upstream collector. The method may also include separately collecting the remainder of the entrained materials that are discharged through the outlet of the conduit. This step of collecting may comprise collecting the pieces of solid matter in a downstream collector.

The above method may include providing an apparatus having a housing with an inlet, an outlet, and an airstream flow path extending from the inlet to the outlet, and applying a vacuum to the housing using an impeller.

According to yet another aspect of this invention there is provided a portable vacuum apparatus for use in gathering pieces of solid matter, including: a housing defining an inlet, an outlet, and an airstream flow path extending from the inlet to the outlet; a centrifugal impeller rotatably mounted on a shaft which is in turn located within the housing, the impeller being positioned so as to displace an airstream carrying pieces of solid matter along the flow passage; an upstream material separator comprising a rotating screen defining a plurality of screen openings therein for removing at least some of the larger and heavier pieces of solid matter from the air stream entering the housing, the screen being located on the same axis as the impeller, in a position upstream and adjacent to the impeller, and rotating with the impeller; an upstream collector for collecting the pieces of solid matter removed by the upstream material separator that is positioned below the upstream material separator and adjacent thereto so that pieces of solid matter may fall from the screen into the collector under the influence of gravity; and a downstream collector in the form of an air permeable bag attached to the outlet of the flow passage for collecting the pieces of solid matter debris that have passed through the impeller and for permitting air from the airstream to be discharged into the environment.

The screen may include any one or more of the features of the screen defined above in the first aspect of the invention. In particular, the screen may be closely spaced from the impeller.

In particular the screen may define an elongate aperture having a longitudinal edge extending in a radial direction from a central region of the screen to an edge region. The longitudinal edge of the aperture may be tapered in section so as to form a sharp edge. A blade may be formed by a longitudinal edge of the elongate aperture. In particular, the blade will be formed by the leading edge of the aperture as the screen rotates.

The screen may define at least two blades each extending from the central region radially out to the edge region. The two blades may be aligned relative to each other so as to extend diametrically across a diameter of the screen. Put another way, when viewed together the blades extend in a straight line across a diameter of the screen.

The housing and the impeller may include any one or more of the features of the first aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS An apparatus for use in gathering pieces of solid matter such as garbage and litter and garden debris in accordance with this invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe at least one embodiment of the invention in detail with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad description.

In the drawings:

Fig 1 is an upper front perspective view of a blower/vacuum apparatus in accordance with a preferred embodiment of the invention;

Fig 2 is a partial upper rear perspective view of the blower/vacuum unit of Fig 1 including some detail of a typical impeller housing;

Fig 3 is a side perspective view of the blower/vacuum unit of Fig 1 in assembled condition with a collection bag attached; Fig 4A is a view of the upstream material separator assembled to the impeller according to one embodiment of the invention;

Fig 4B is a view of the upstream material separator assembled to the impeller according to an alternative embodiment of the invention; Fig 5 is a side view of the blower/vacuum apparatus of Fig 1 without the collection bag attached;

Fig 6A is an exploded three dimensional view of part of the apparatus according to one embodiment of the invention in which the upstream material separator is co-axially secured to the impeller; Fig 6B is an exploded three dimensional view of part of the apparatus according to an alternative embodiment of the invention in which the upstream material separator is mounted on the same axis as the impeller;

Fig 7 is a schematic longitudinal sectional view through the housing of the blower/ vacuum apparatus of Fig 1 showing how the different sizes of debris and garbage are directed into the upstream and downstream collectors;

Fig 8 is an overhead perspective view of the upstream collector in accordance with the blower/vacuum apparatus of Fig 1 ;

Fig 9 is an underside view of the vacuum cowling and inlet duct assembly of the blower vacuum apparatus of Fig 1 ; and Fig 10 is a schematic sectional view of the housing, upstream material separator and impeller of an apparatus in accordance with a further embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In Figs 1 to 10, reference numeral 1 refers generally to an apparatus for use in gathering up pieces of solid matter in accordance with the embodiments of the invention described below.

Referring generally to the accompanying drawings, there is depicted an apparatus for use in gathering up pieces of solid matter in the form of a portable blower/vacuum unit 1. The blower/vacuum unit 1 has a centrifugal impeller 3 which is rotationally driven by a motor 5. The impeller 3 is contained within a housing 7 in the form of a circular scroll case which protects but also allows air flow around the impeller 3. The impeller housing 7 is typically moulded from a structural plastic material in order to protect it and also the user from the impeller 3 and air borne debris. The impeller 3 has impeller blades 9 and is rotatably connected to a power source that causes the impeller to rotate. The apparatus has an upstream material separator in the form of a screen 13. In one embodiment of the invention, the screen 13 which is also circular and has a smaller diameter than the impeller 3 is co-axially secured to the impeller 3 by a securing bolt 11a, washer 17, nut 19 and spacer bush 20. Fig 6A in particular shows the relationship between the upstream material separator or screen 13a and the impeller 3. The screen 13a is located closely adjacent to the impeller 3 in order to protect the impeller 3 from larger and/or higher density debris. The screen 13a is thus caused to rotate in the same direction and at the same speed as the impeller 3. According to an alternative embodiment of the invention shown in Figs 4B and 6B, the screen 13b is located on the same axis as the impeller closely adjacent to but independent of the impeller. The screen 13b is secured in place by a securing bolt 11b located co-axially with the centre-line of the impeller, washer 17 and nut 19.

The screen 13a, 13b comprises a substantially circular plate having two major surfaces defining a central hub region and a screen region radially outward of the hub region. The hub region of the screen 13a, 13b defines an opening through which the securing bolt 11a, 11b passes. The screen region defines a plurality of openings 23 therein for screening out larger and/or higher density materials while permitting smaller and/or lower density materials to pass therethrough.

Further, the screen 13a, 13b defines two apertures 25, each having a longitudinal edge extending in a radial direction from the central hub region of the screen to its outer region. A longitudinal edge of each aperture 25 is tapered in section so as to form a sharp edge or blade edge 27a, 27b. In the above embodiments, there are two leading edge blades 29a, 29b, the elongated apertures 25 preceding each blade edge 27a, 27b. The blades 29a, 29b are aligned relative to each other so as to extend diametrically across a diameter of the screen. The blades 29a, 29b are designed to cut or chip debris passing through the screen 13a, 13b into smaller pieces and also assist in deflecting larger debris away from the impeller 3 as the screen 13a, 13b rotates.

The blower/vacuum 1 has an air inlet 31 and an air outlet or discharge port 33. An inlet conduit 35 is releasably attached to the air inlet 31 and positioned so that air is drawn along the rotational axis of the impeller 3 in order to maximise suction. The inlet conduit 35 may be secured to the air inlet 31 by any acceptable means. The inlet conduit 35 may be secured into position by any acceptable means such as by means of co-operating flanges (not shown) on the outside of the air inlet 31 and blower pipe respectively.

The blower/vacuum 1 has an upstream collector 36. Preferably, the upstream collector 36 is in the form of a tank although it is possible that it may take the form of a reinforced bag. Larger and heavier debris is deflected by the screen 13a, 13b and blades 29a, 29b and passes through a tubular outlet 37 into the upstream collector 36. The upstream collector 36 is releasably attached to the blower-vacuum 1 to enable this to be conveniently emptied by the user. The upstream collector 36 is shown detached from the blower-vacuum in Fig. 8.

The upstream collector 36 may be fastened to the blower/vacuum 1 by any operatively secure means. In this embodiment, the upstream collector 36 is fastened to the blower- vacuum 1 by means of a latch 38 and spring socket 39 arrangement. The upstream collector 36 is released when the user pulls on the release handle 41. Fig 9 shows the underside view of vacuum cowling 43 and the inlet duct assembly of the blower/vacuum 1. The vacuum cowling 43 has a rubber seal 45 which forms a seal around the periphery of the upstream collector 36 when the upstream collector 36 is attached.

A downstream collector in the form of collection bag 47 is releasably attached to the air outlet or discharge port 33 to catch low density material such as dust and small debris expelled from the air outlet or discharge port 33. The collection bag 47 may be connected to the air outlet 33 or discharge port 33 by any suitable fastening arrangement. In this embodiment, the collection bag 47 is attached to the discharge port 33 by a "twist lock" moulded plastic connector 49, or similar fastening method. The blower/vacuum 1 has a handle 51 above the motor 5 for easy portability and also an additional side handle 53 to assist the user in manoeuvring the blower-vacuum 1.

In use, the centrifugal impeller 3 is rotationally driven by the motor 5. The impeller 3 draws air into the impeller housing 7 via the air inlet 31 and forces air out of the impeller housing 7 through the air outlet or discharge port 33. The resulting air flow pathway creates a partial vacuum and suction necessarily develops at the air inlet 31.

The free end of the inlet conduit 35 is pointed towards dust or other debris. The vacuum draws air laden with debris into the inlet conduit 35. Some of the materials in the airstream are separated from the airstream by the upstream material separator before they reach the impeller. These materials are typically those which are larger and/or of greater density in the airstream. Some of the larger or heavier materials are deflected by the screen 13a, 13b and the blades 29a, 29b away from the impeller 3. These materials then fall by gravity from the upstream material separator into the upstream collector 36 from where they can be disposed of. The blades 29a, 29b operate to cut or chip debris into smaller pieces which may then be small enough to pass through the openings 23 in the screen 13a, 13b. Air and any entrained smaller materials of lower density such as dust and small debris, being the remaining materials not removed by the upstream material separator, then pass through the openings 23 in the screen 13 to the impeller 3 and are discharged centrifugally by the blades of the impeller into the volute form 55 of the impeller housing 7 which terminates in the air outlet or discharge port 33. The air together with the air borne debris is then expelled via the air outlet or discharge port 33 (defined by a tubular section at one side of the impeller housing 7) into the downstream collector (in this case a collection bag of an air permeable fabric) from where they can be disposed of. The air from the airstream passes out of the downstream collector and into the environment. Fig 7 is a schematic longitudinal sectional view through the housing of the apparatus which shows how the different sizes of debris and garbage are directed into the upstream and downstream collectors.

The blower/vacuum can be operated in either vacuum or blower mode. The blower/vacuum unit 1 can therefore be used selectively to either suck debris or to blow and gather debris. The blower/vacuum 1 may be converted from vacuum mode to blower mode, by disconnecting the vacuum cowling 43 from the power unit and by connecting an alternative air conduit (not shown) to the air outlet or discharge port 33. The air conduits may be connected to the suction and discharge circuits by any suitable means. This may be by way of complementary releasable engagement formations e.g., co-operating flanges, a screw in or snap fit arrangement or some other form of releasable coupling arrangement.

Although not shown, the blower/vacuum unit may be provided with connection means for removably or permanently fitting additional parts, fittings or accessories to the unit. Such fittings may include a safety grille to be fitted over the impeller and screen. Fittings and accessories may include an extension pipe, tube or hose, where required. Other fittings and accessories may also include other releasable forms of collector of suitable material and sufficient strength for the intended purpose. Such collectors may be connected by any suitable fastening arrangement.

Although not shown, the blower/vacuum unit may also optionally be provided with a vacuum release valve. It is possible that the debris may become caught anywhere in the inlet conduit 35 or that the inlet conduit 35 may become blocked or clogged. In the event that debris or other unintended items become clogged at a point in the suction circuit, this puts strain on the motor. In the event that material becomes caught in the impeller, this may also potentially damage the impeller housing. The release valve enables the suction circuit to be quickly released, thereby preventing potential damage to the motor or impeller housing. This is also an added safety feature for the user. The apparatus may also optionally include a safety grille to be fitted over the impeller and screen.

A metal plate 15 shown in Fig. 5 may optionally be positioned to protect the inner face of the scroll case so as to provide a dust seal. This also acts to protect the moulded plastic face of the scroll case from overheating due to friction from debris moving at high speed in the airstream flow path.

An alternative embodiment of an apparatus in accordance with this invention is shown in Fig 10. The embodiment in Fig 10 has some similarities with the embodiment described above with reference to Figs 1 to 9. Accordingly, unless otherwise indicated, the same reference numerals will be used to refer to the same components.

The following description will focus on the difference between this embodiment and the Fig 1 embodiment.

In Fig 10 the upstream material separator comprises a screen 13c which is mounted to the housing 7 around its circumference. A rotating blade 29c is secured by securing bolt 11 , washer 17, nut 19 and spacer bush 20 in front of the impeller and behind the screen 13c. Thus the blade 29c rotates together with the impeller 3.

In one form, the blade 29c may comprise two blade elements extending from a central axis to a free end and these blades 29c may be linearly aligned with each other somewhat like a propeller. In use, the screen 13c separates at least some particles, e.g. larger and heavier particles from the airstream. Some of the pieces of solid material that pass through the screen 13c are cut into smaller pieces by the rotating blade 29c. For example, pieces of flexible material such as paper and leaves can be cut up by the blade in this way.

The airstream and the entrained particles then pass through the impeller and into the downstream collector which is an air permeable bag as described above.

An advantage of the apparatus as described above with reference to Figures 1 to

10 is that it is able to screen out some of the pieces of solid matter in the airstream, e.g. particularly relatively large pieces of solid material and pieces of paper and leaves, passing through the apparatus upstream of the impeller, i.e. before it reaches the impeller. Consequently, the service life of the apparatus is increased.

A further advantage of the apparatus described above with reference to the drawings is that it is able to reduce the number of pieces of solid matter coming into contact with the impeller without significantly reducing the suction that is applied by the apparatus. This is advantageous because the efficacy of the apparatus is determined in a large part by the strength of the suction that can be applied by the apparatus as this determines its ability to pick up pieces of solid matter.

A further advantage of the apparatus described above with reference to the drawings is that it has one or more blades that cut pieces of flexible sheet material such as paper, material and leaves when they come into contact therewith. This reduces the size of these pieces of flexible sheet material such that they are less inclined to tie up and jam the impeller.

A further advantage of the apparatus described above is that the screen can be manufactured at reasonable cost by cutting and punching various edges and openings out of sheet steel. Accordingly, the additional feature to separate out some particles upstream of the impeller can be provided at a modest additional cost.

A further advantage of the apparatus described above is that an upstream collector can be positioned below the screen and adjacent to the screen e.g. in a longitudinal direction, and upstream thereof. By providing the collector below the screen, the particles separated out by the screen can fall into the collector under the influence of gravity. This is easier and simpler than getting a contrivance to deliver the pieces of solid matter into the collector. A further advantage is that the collector can be formed as part of the housing.

A further advantage of the apparatus described above is that it minimises handling of the debris by the user. This is important for reasons of hygiene and where the debris or other solid articles pose a disposal hazard, for example, syringes, needles, razor blades and other "sharps".

In the present specification and claims, the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.

It will of course be realized that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the invention as is herein set forth.

Claims

1. A portable vacuum apparatus, including: a housing defining an inlet, an outlet, and an airstream flow path extending from the inlet to the outlet; an impeller mounted in the airstream flow path of the housing; and a rotatable material separator in said airstream flow path of the housing, upstream of the impeller.

2. A portable vacuum apparatus as claimed in claim 1 , wherein the flow path has a longitudinal axis and the rotatable material separator rotates in parallel alignment therewith.

3. A portable vacuum apparatus as claimed in claim 1 , wherein the impeller and the rotatable material separator rotate about axes which are substantially parallel to one another.

4. A portable vacuum apparatus as claimed in claim 1 , wherein the impeller and the rotatable material separator rotate co-axially with one another.

5. A portable vacuum apparatus as claimed in any one of the preceding claims wherein the rotatable material separator is located adjacent to the impeller.

6. A portable vacuum apparatus as claimed in any one of the preceding claims wherein the rotatable material separator is a rotatable screen.

7. A portable vacuum apparatus as claimed in claim 6, wherein the openings in the rotatable screen are dimensioned to prevent the passage of materials entrained within the airstream, on the basis of size.

8. A portable vacuum apparatus as claimed in claim 6 or 7, wherein the screen is substantially planar.

9. A portable vacuum apparatus as claimed in claim 8 wherein the screen has a substantially circular configuration.

10. A portable vacuum apparatus as claimed in any one of claims 6 to 9, wherein the screen rotates in the same direction as the impeller.

11. A portable vacuum apparatus as claimed in any one of claims 6 to 9, wherein the screen is mounted on the impeller and rotates in the same direction and at the same speed as the impeller.

12. A portable vacuum apparatus as claimed in any one of claims 6 to 10, wherein the screen rotates in the same direction but at a different speed to the impeller.

13. A portable vacuum apparatus as claimed in any one of claims 6 to 12, wherein the screen is closely adjacent to the impeller.

14. A portable vacuum apparatus as claimed in any one of claims 6 to 1 , wherein the screen is positioned immediately in front of the impeller.

15. A portable vacuum apparatus as claimed in any one of claims 6 to 14, wherein the screen defines at least one elongate aperture having longitudinal edges extending in a radial direction from a central region of the screen to an edge region.

16. A portable vacuum apparatus as claimed in claim 15 wherein the longitudinal edge of the aperture(s) is tapered in section so as to form a sharp edge.

17. A portable vacuum apparatus as claimed in any one of claims 6 to 16, wherein the screen includes at least one blade.

18. A portable vacuum apparatus as claimed in any one of claims 6 to 17, wherein the screen includes at least one leading edge blade.

19. A portable vacuum apparatus as claimed in claims 17 or 18, wherein the blade is formed by one of the longitudinal edges of the elongate aperture.

20. A portable vacuum apparatus as claimed in any one of claims 17 to 19, wherein the blade is formed by the leading edge of the aperture as the screen rotates.

21. A portable vacuum apparatus as claimed in any one of claims 6 to 18, wherein the screen defines at least two blades each extending from the central region radially out to the edge region.

22. A portable vacuum apparatus as claimed in claim 21 , wherein the blades are aligned relative to each other so as to extend diametrically across a diameter of the screen.

23 A portable vacuum apparatus, including: a housing defining an inlet, an outlet, and an airstream flow path extending from the inlet to the outlet; an impeller mounted in the airstream flow path of the housing; and a material separator in said airstream flow path of the housing, upstream of the impeller, wherein the material separator is a screen which has at least one rotating blade with at least one cutting edge positioned in series therewith.

24. A portable vacuum apparatus as claimed in, claim 23, wherein the blade is positioned upstream of the screen.

25. A portable vacuum apparatus as claimed in claim 23 wherein the blade is positioned downstream of the screen.

26. A portable vacuum apparatus as claimed in any one of claims 23 to 25 wherein the rotating blade is fixedly mounted on a shaft being the same shaft that is used to rotate the impeller.

27. A portable vacuum apparatus according to any one of claims 23 to 26, wherein the blade may comprise at least two blade elements, each extending radially out from the axis of rotation to a free end.

28. A portable vacuum apparatus as claimed in claim 27, wherein the free ends of the blade elements are positioned radially adjacent the circumferential edge of the centrifugal impeller.

29. A portable vacuum apparatus as claimed in any one of the preceding claims and including an upstream material collector in communication with the material separator.

30. A portable vacuum apparatus as claimed in claim 29, wherein the upstream material collector is positioned vertically below the screen and adjacent the screen, and upstream thereof,

31. A portable vacuum apparatus as claimed in claim 30, wherein the upstream material collector is positioned in a longitudinal direction.

32. A portable vacuum apparatus as claimed in any one of claims 29 to 31 , wherein the upstream material collector is unitarily formed with the housing or part of the housing.

33. A portable vacuum apparatus as claimed in any one of claims 29 to 31 , wherein the upstream material collector is releasably attached to the housing or part of the housing.

34. A portable vacuum apparatus as claimed in any one of claims 29 to 31 or 33, wherein a sealing means forms a seal around the periphery of the upstream material collector when the upstream collector is attached to the apparatus.

35. A portable vacuum apparatus as claimed in any one of claims 29 to 32, wherein the upstream material collector has a discharge opening through which debris collected therein can be discharged from the collector.

36. A portable vacuum apparatus as claimed in any one of claims 29 to 35, wherein the upstream material collector has solid walls that are not air permeable.

37. A portable vacuum apparatus as claimed in claim 36, wherein the walls of the upstream material collector are rigid.

38. A portable vacuum apparatus as claimed in any one of the preceding claims and including a downstream material collector, downstream of the impeller.

39. A portable vacuum apparatus as claimed in claim 38 wherein the downstream material collector is releasably attached to the outlet.

40. A portable vacuum apparatus as claimed in claim 39 wherein the housing includes releasable engagement formations and the downstream collector includes complementary releasable engagement formations for releasably coupling the collector to the outlet.

41. A portable vacuum apparatus as claimed in claim 38, wherein the downstream material collector has a discharge opening through which debris collected therein can be discharged.

42. A portable vacuum apparatus as claimed in any one of claims 38 to 41 , wherein the downstream material collector is a bag of air permeable material.

43. A portable vacuum apparatus as claimed in any one of the preceding claims, wherein the apparatus includes an inlet conduit.

44. A portable vacuum apparatus as claimed in claim 43, wherein the inlet conduit is releasably attached to the inlet.

45. A portable vacuum apparatus as claimed in claims 43 or 44, wherein the inlet conduit is one integrally formed piece.

46. A portable vacuum apparatus as claimed in any one of the preceding claims, wherein the apparatus includes at least one handle.

47. A portable vacuum apparatus as claimed in any one of the preceding claims, wherein the apparatus includes a shoulder strap.

48. A portable vacuum apparatus as claimed in any one of the preceding claims, wherein the apparatus is capable of being operated in either vacuum or blower mode.

49. A rotatable screen for mounting to a vacuum apparatus, the screen comprising: a flattened member having two major surfaces defining a central hub region and a screen region radially outward of the hub region, the screen region defining a plurality of screen openings therein for screening out materials, and the hub region being for mounting the member to a shaft for rotating the screen in use.

50. A rotatable screen as claimed in claim 49, wherein the screen is substantially planar.

51. A rotatable screen as claimed in claims 49 or 50, wherein the screen is of substantially circular configuration.

52. A rotatable screen as claimed in any one of claims 49 to 51 , wherein the hub region of the screen defines an opening through which a rotatable shaft is passed and to which the screen can be mounted in use.

53. A rotatable screen as claimed in any one of claims 49 to 52, wherein the screen region defines at least 10 screen openings therein.

54. A rotatable screen as claimed in any one of claims 49 to 53, wherein the screen region defines 10 screen openings to 25 screen openings.

55. A rotatable screen as claimed in any one of claims 49 to 53, wherein the screen defines at least one elongate aperture having a longitudinal edge extending in a radial direction from the central region of the screen to the edge region.

56. A rotatable screen as claimed in claim 55, wherein a longitudinal edge of an aperture is tapered in section so as to form a sharp edge.

57. A rotatable screen as claimed in claim 56, wherein a blade is formed by a longitudinal edge of an aperture.

58. A rotatable screen as claimed in claim 57, wherein the blade is formed by the leading edge of the aperture as the screen rotates.

59. A rotatable screen as claimed in any one of claims 49 to 58, wherein the screen includes at least one blade.

60. A rotatable screen as claimed in any one of claims 49 to 59, wherein the screen includes at least two blades, each extending from the central region radially out to the circumferential edge region.

61. A rotatable screen as claimed in claim 60, wherein the blades are aligned relative to each other so as to extend diametrically across the diameter of the screen.

62. A rotatable screen as claimed in any one of claims 49 to 61 , wherein the screen is comprised of sheet steel and the openings are formed out of sheet steel.

63. A portable vacuum apparatus, including: a housing defining an inlet, an outlet ,and an airstream flow path extending from the inlet to the outlet; an impeller rotatably mounted on a shaft in the airstream flow path of the housing; and an upstream material separator comprising a rotating screen defining a plurality of screen openings therein, the screen being located on the same axis as the impeller, upstream of and adjacent to the impeller, and rotating with the impeller.

64. A portable vacuum apparatus as claimed in claim 63, and including an upstream material collector positioned below the screen and adjacent thereto so that pieces of solid matter may fall from the screen into the collector under the influence of gravity.

65. A portable vacuum apparatus as claimed in claim 63 or 64, and including a downstream material collector in the form of an air permeable bag mounted over the outlet of the flow passage.

66. A portable vacuum apparatus as claimed in any one of claims 63 to 65, wherein the rotatable screen includes any one or more of the features in claims 49 to 62.

67. A portable vacuum apparatus, including: a housing defining an inlet, an outlet ,and an airstream flow path extending from the inlet to the outlet; an impeller rotatably mounted on a shaft in the airstream flow path of the housing; and a material separator in said airstream flow path of the housing, upstream of the impeller, wherein the material separator is a screen defining a plurality of screen openings therein having at least one rotating blade with at least one cutting edge positioned in series with the screen.

68. A portable vacuum apparatus as claimed in claim 67, wherein the blade is positioned upstream of the screen.

69. A portable vacuum apparatus as claimed in claim 68, wherein the blade is positioned adjacent to the screen.

70. A portable vacuum apparatus as claimed in claim 67, wherein the blade is positioned downstream of the screen.

71. A portable vacuum apparatus as claimed in claim 70, wherein the blade is positioned closely adjacent to the screen,

72. A portable vacuum apparatus as claimed in claim 71 , wherein the blade is sandwiched between the impeller and the screen.

73. A portable vacuum apparatus as hereinbefore described with reference to the accompanying drawings.

74. A method of gathering up pieces of solid matter, the method comprising the following steps: providing a portable vacuum apparatus including: a housing defining an inlet, an outlet, and an airstream flow path extending from the inlet to the outlet, an impeller mounted in the airstream flow path of the housing; a rotatable material separator in said airstream flow path of the housing, upstream of the impeller; applying a vacuum to the housing; drawing an airstream with entrained pieces of solid matter through the housing; separating out some of the pieces of solid matter drawn into the housing by means of the rotatable material separator; and passing the airstream and the remainder of the entrained pieces of solid matter through the impeller and then discharging it through an outlet.

75. A method of gathering up pieces of solid matter as claimed in claim 74 wherein the step of separating some of the pieces of solid matter comprises separating out materials by means of openings in the rotatable material separator dimensioned to prevent the passage of materials entrained within the airstream on the basis of size and/or density.

76. A method of gathering up pieces of solid matter as claimed in claims 74 or 75 wherein the method includes collecting the pieces of solid matter that are separated out of the airstream upstream of the impeller.

77. A method of gathering up pieces of solid matter as claimed in claim 76, wherein the pieces of solid matter are collected in an upstream collector.

78. A method of gathering up pieces of solid matter as claimed in any one of claims 74 to 77, wherein the method includes separately collecting the remainder of the entrained materials that are discharged through the outlet of the housing.

79. A method of gathering up pieces of solid matter in accordance with claim 78, wherein the pieces of solid matter are collected in a downstream collector.