WO1999013761A1

WO1999013761A1 - Vacuum cleaner

Info

Publication number: WO1999013761A1
Application number: PCT/GB1998/002745
Authority: WO
Inventors: Christopher Robert Duncan; Michael Edward Gailes
Original assignee: Numatic International Limited
Priority date: 1997-09-12
Filing date: 1998-09-11
Publication date: 1999-03-25
Also published as: AU9085598A; GB9719458D0

Abstract

The present invention relates to vacuum cleaners, and in particular relates to methods of improving the efficiency of the cleaning action. According to the present invention there is provided a vacuum cleaner comprising vacuum means for providing suction, which vacuum means is adapted to be powered by a supply of high voltage alternating electric current, a nozzle portion remote from the vacuum means and including an electrically powered surface treatment device, characterized by low voltage power generation means for the treatment device in which a low voltage power supply is derived from the high voltage power supply to the vacuum means, by the said high voltage supply being isolated from the ancillary device and by electrical connection means provided between the treatment device and the low voltage generation means.

Description

VACUUM CLEANER

The present invention relates to vacuum cleaners, and in particular relates to methods of improving the efficiency of the cleaning action.

Typical vacuum cleaners may be divided into two general types: "cylinder" cleaners and "upright" cleaners. Cylinder cleaners typically comprise a body portion containing the vacuum drive and waste bin for collected material. A cleaning nozzle is attached to the body portion by means of an air conduit, which conduit comprises a flexible portion which is attached to the body portion, and a rigid portion which extends from the flexible portion and is attached to the cleaner nozzle. The conduit serves to provide a passage for the collection of material lifted from the surface being cleaned as well as providing a mechanical link between the cleaning nozzle and the body portion whereby in use the body portion may follow the user about an area to be cleaned as the user moves over a surface with the cleaning nozzle. The rigid portion of the conduit typically provides a hollow handle to which the cleaning nozzle is connected.

The typical upright cleaner has a collecting nozzle assembly which comprises a chamber adapted to be disposed above a surface to be cleaned and is supported by rollers for ease of translational movement over a surface to be cleaned. The chamber is provided with a driven rotatable brush which disturbs the dirt on the surface for entrainment in the passing airstream for transport to a collecting bag. The bag is supported on a handle attached to an upper portion of the nozzle chamber. The roller brush and the air transport fan are driven by the same, high voltage electric motor.

In attempting to improve the performance of cylinder type machines, it is known to provide brushes at the working end of the nozzle. The brushes serve to lift dirt and loose matter from the surface being cleaned so that it can be entrained in the air flow through the nozzle. Attempts have been made further to improve the nozzles by driving the brushes so that they rotate against the surface being cleaned, as with upright machines. This has been done by providing a separate electric motor in the nozzle, which motor is powered by an electrical connection to the body portion which is in turn connected to the mains power supply. However such arrangements have been found to be complex and costly to manufacture because of the need to provide adequate safety measures to prevent accidental electric shocks caused by failure of insulation in the electrical connection between the high voltage mains supply and the electric motor of the brush in the nozzle. Typically the nozzle of the vacuum cleaner is detachable from the flexible hose and the electrical junction formed at the point of detachment is prone to failure. Thus, for example, when wet, the nozzle can become "live" thus presenting a potential hazard to the user. In order to overcome this problem a complex arrangement of insulated cables, slip-rings and connectors is required to achieve an acceptable level of safety.

Attempts to overcome this problem have been by providing a separate power supply to a powered nozzle, which supply is clipped to the hose and handle. In use, however, this is cumbersome and the separate power supply lead tend to detach from the hose too easily.

Another attempted solution has been to replace the electric drive for the brushes with a turbo system whereby the brushes are driven by the air flow through the nozzle. The turbo system reduces the collecting efficiency of the air stream overall; but dirt and fibrous matter tends to collect in the curbine thus inhibiting or stopping the operation of the turbine and hence the brushes. It is therefore an object of the present invention to provide a vacuum cleaner with an ancillary nozzle device which incorporates a driven rotary brush which does not suffer from the complexity and problems of the prior art.

According to the present invention there is provided a vacuum cleaner comprising vacuum means for providing suction, which vacuum means is adapted to be powered by a supply of high voltage alternating electric current, a nozzle portion remote from the vacuum means and including an electrically powered surface treatment device, characterized by low voltage power generation means for the treatment device in which a low voltage power supply is derived from the high voltage power supply to the vacuum means, by the said high voltage supply being isolated from the ancillary device and by electrical connection means provided between the treatment device and the low voltage generation means.

According to one aspect of the present invention there is provided a cleaner as described above wherein the nozzle comprises an elongate rigid member which carries at one end thereof the treatment device, in which member there is formed an air conduit for the passage of air- entrained vacuumed material, characterised in that the electrical connection means is accommodated interior of external walls of the member.

The electrical conduction means may be accommodated in an elongate chamber provided interior of the external walls of the member and separate from the air conduit.

According to another aspect of the present invention the is provided a cleaner as hereinbefore described wherein a length of flexible tubing provides a flexible air conduit between the nozzle and the vacuum means and characterised in that the electrical conduction means is accommodated interior of external walls of the flexible tubing .

The electrical conduction means may be disposed within a flexible elongate sheath juxtaposed an inside surface of the flexible tubing.

According to yet another aspect of the present invention there is provided a cleaner as hereinbefore described wherein the electrical conduction means comprises a slip ring assembly permitting rotation of one portion of the conduction means relative to another portion of the conduction means without twisting of the said portions of the electrical conduction means. Preferably the slip ring assembly is adapted to permit 360 degree rotation of one portion relative to the other.

In an embodiment of this aspect of the invention the slip ring assembly defines therein a slip ring air conduit for air-entrained vacuumed matter drawn from the nozzle towards the vacuum means .

The slip ring assembly may comprise two spaced apart contact rings an two sliding contact members, one urged against one contact ring and the other urged against the other contact ring, the arrangement permitting relative sliding contact of the members and rings.

The slip ring assembly may comprise treatment device activation means comprising a switch member operatively connected to the sliding contact members and movable to detach one or more of the contact members from one or more of the contact rings, thereby to break the electric circuit between the treatment device and the low voltage supply means.

In another aspect of the invention there is provided a cleaner as hereinbefore described characterised in that the electrical conduction means comprises a plug and socket combination comprising an external electrical connection point provided in a housing of the vacuum means, and a detachable flexible connector leading to a detachable air conduit which provides air communication with the nozzle.

Vacuum cleaners are typically powered by mains power supplies which operate at a high voltage, typically 240 V or 110 V. The vacuum means are driven by alternating current motors capable of operating under the mains power supply. This has naturally led to the design of vacuum cleaners with ancillary treatment devices, such as brushes, which are also powered by the same power supply for the sake of simplicity. The present invention takes a different approach by providing a low voltage power source for the ancillary device which is far less dangerous if, for whatever reason the cleaner or a portion thereof becomes electrically live.

By low voltage the applicant means not greater than 50 V, and preferably 42 V or less. In one embodiment of the invention, the low voltage supply is 24 V and the motor in the powered head is rated accordingly.

The low voltage generation means may comprise a transformer which steps the mains supply down in voltage.

The transformer is preferably disposed in a body portion of the vacuum cleaner.

The generation means may further comprise a rectifier for converting the a.c. voltage to direct current so that a direct current motor may be used in the ancillary device.

It is within the scope of the present invention to provide upright cleaners according to the present invention. However in a preferred arrangement there is provided a vacuum cleaner of a type wherein the nozzle portion is external of a body portion of the cleaner, and wherein an air conduit extending between the nozzle portion and the body portion comprises a length of flexible tubing. This includes cleaners known as a cylinder vacuum cleaners. The electrical connection means may be included in, or associated with, the air conduit. Because the electrical connection means carries, in use, low voltage electricity there is far less danger to the user, and the cleaner may be used in moist conditions without worry of accidental electrocution.

In a particular aspect of the invention the air conduit comprises hose and a rigid portions, one end of which rigid portion carries the nozzle; ar. electrical conducting means may be incorporated in said hose and rigid portion to effect a connection between the nozzle and the low voltage source on the machine body.

The surface treatment device may comprise, for example, a brush driven by an electric motor or a power shampoo head adapted to provide a wet cleaning action, but other devices will be known to the person skilled in the field and are capable of being applied using the present invention.

Following is a description by way of example only and with reference to the drawings of a method of putting the present invention into effect.

In the drawings :-

Figure 1 is a side elevation of a vacuum cleaner according to the present invention.

Figure 2 shows a section through a nozzle member shown in figure 1.

Figure 3 shows detail of a releasable connector between portions of the nozzle member.

Figure 4 shows detail of a slip ring assembly shown in figure 1. Figure 5 shows the action of a sliding switch involving the slip rings.

Figure 6 is a section through a flexible hosing portion of the cleaner shown in figure 1.

A vacuum cleaner according to the present invention is shown generally as 1 in figure 1. The vacuum cleaner consists of: a bin-type body portion 10 which houses a dust collector and vacuum generator; a flexible hose 11 which communicates with the vacuum generator and engages with the body portion at a releasable bayonet-type connector 12; a rigid nozzle 9,9' which is attached to a distal end of the flexible hose 11 by means of a slip ring assembly 13; and a cleaning head 15 attached to a distal end of the nozzle.

The cleaning head comprises a housing 16 which is a generally rectilinear enclosure having a top wall 17 a front wall 18 a rear wall 19 and a bottom wall 20. A rectangular slot 21 forms an opening in a front portion of the bottom wall 20. Two side walls 23 (not shown) carry between them a cylindrical roller 24. The roller carries a plurality of bristles 26 over its outside surface. The roller is positioned such that the bristles protrude through slot 21 whereby they may be brought into contact with the surface to be cleaned. A filet 31 adjacent the slot prevents brushed-up dirt from falling back through the slot. Rollers 33,34 support the cleaning head for movement over the surface to be cleaned.

A rigid elongate nozzle member 35 is entered into an upper rear corner 36 of the chamber. The nozzle member engages a rotatable mounting 37 which permits the nozzle member to be swivelled to maintain contact with the surface to be cleaned as the nozzle is directed over the surface.

The nozzle member has a cross section as shown in figure 2. The nozzle is formed with three side by side elongate chambers. The central chamber 40 serves as an air conduit which carries air-entrained dirt from the cleaning head back towards the vacuum generator. The right hand side chamber 41 accommodates one 24 V power supply cable 42. The left hand chamber 43 accommodates another 24 V power supply cable 44. By accommodating the cables in separate spaced-apart chambers the possibility of short circuiting between cables, even in wet conditions, is greatly reduced.

Figure 3 is a top view of an end region 50 of the nozzle member distal from the cleaning head. The end is formed with a recess 51 shown with dashed lines in the figure. A back wall 52 of the recess carries two spaced apart contacts 53,54. The contacts are soldered on a cleaning head side of the wall to the power cables 42,44. The recess acts as a female portion of a friction fit connector between the nozzle member and a nozzle member handle portion 60 (shown in figure 1) . The handle portion is provided with a male portion 61 which corresponds to the recess 51. A front wall 62 of the male portion is formed with two spaced apart apertures which receive the power cable contacts 53,54 when the male an female portions are engaged. Adjacent the apertures, behind the front wall 62 are mounted two electrical contacts 64,65. These are position so that when the male and female portions are engaged the respective pairs of contacts 53,64 and 54,65 in the nozzle member and handle portion form an electrically conducting contact. A rear end of each handle portion contact 64,65 is soldered to a respective handle portion power supply cable 67,68. These cables are accommodated in separate chambers of the handle portion, either side of a handle portion air conduit (not shown) .

Figure 4 shows top view of another end 69 of the handle portion. The other ends of the cables 67,68 are shown soldered to resilient contact members 70,71. These contact members are shown side on in figure 4b in which raised contact domed bushes are shown as 72,73. The contact members are made of respective leaves of copper sheet bent to form the shape shown. The solder points on top of each contact are trapped between two halves of an insulating member 74 which is folded over about web portion 75. Lower portion 76,77 of each contact member form individual leaf springs used as part of the slip ring assembly shown in figure 5.

Figure 5 shows a side on view of the distal end of the flexible hose 11 engaged with the handle portion 9, shown cut away. The hose terminates in a collar 80 which carries two co-axial spaced apart slip rings 81,82. When the handle portion is engaged with the hose collar (by a standard snap-fitting mechanism, not shown) the contact members are aligned over the slip rings and urged into intimate electrical contact therewith, as shown in the figure. The insulating member is attached to an elongate slider switch member 84 which is formed at one end thereof with a raised button 85 which may be pushed by the thumb of the user grasping the handle. Movement of the switch forwards S or backwards S¹ as shown in the figure connects or disconnects the circuit with the 24 V power supply, thereby activating or de-activating the cleaning head brush. The "on" configuration is shown in figure 5A and the "off" configuration is shown in figure 5B in which the switch has been moved back and the contact members translated backwards, breaking the circuit. The slip rings carry internally thereof respective solder tabs (not shown) . To these tabs are soldered respective flexible hose power supply cables. The exposed solder connections are coated in epoxy resin to provide an insulated protective layer up to the cable insulating sheathing. These cables are accommodated side by side in a flexible thermoset plastics material tube 85 shown in the sectional view through the hose in figure 6A. The tube is attached to an inside surface of the flexible hosing by plastics welding between the respective hose and tube materials.

The other ends of the power cables are electrically connected to an electrical socket 86 in a hose collar 87 shown in figure 1. The collar is releasably connected to the housing by means of a standard bayonet-type connector 90. The socket 86 engages with a corresponding plug 91. The plug is provided with cabling to a 24 V external power supply socket 92 provided in an exterior wall 93 of the housing.

The housing is provided with a mains power supply cable (not shown) which plugs into household mains power supply (e.g. 240 V or 110 V). This supply powers the vacuum generator of known type. The high voltage supply is passed through a step-down transformer 98 to produce a 24 V ancillary supply for the cleaning head brush motor. Preferably a rectifier in incorporated in the circuit in order to permit the use of a standard 24 V D.C. motor.

The foregoing invention provides an improved arrangement for transmitting power to an ancillary floor treatment motor in a cleaning head, by concealing and shielding the supply cabling interior of one or more of the various portions of the air conduit defining members of the vacuum cleaner.

Claims

1. A vacuum cleaner comprising vacuum means for providing suction, which vacuum means is adapted to be powered by a supply of high voltage alternating electric current, a nozzle portion remote from the vacuum means and including an electrically powered surface treatment device, characterized by low voltage power generation means for the treatment device in which a low voltage power supply is derived from the high voltage power supply to the vacuum means, by the said high voltage supply being isolated from the ancillary device and by electrical connection means provided between the treatment device and the low voltage generation means .

2. A cleaner as claimed in claim 1 wherein the nozzle comprises an elongate rigid member which carries at one end thereof the treatment device, in which member there is formed an air conduit for the passage of air-entrained vacuumed material, characterised in that the electrical connection means is accommodated interior of external walls of the member.

3. A cleaner as claimed in claim 2 characterised in that the electrical conduction means is accommodated in an elongate chamber provided within the external walls of the member and separate from the air conduit.

4. A cleaner as claimed in any preceding claim wherein a length of flexible tubing provides a flexible air conduit between the nozzle and the vacuum means and characterised in that the electrical conduction means is accommodated interior of external walls of the flexible tubing.

5. A cleaner as claimed in claim 4 characterised in that the electrical conduction means is disposed within a flexible elongate sheath juxtaposed an inside surface of the flexible tubing.

6. A cleaner as claimed in any preceding claim wherein the electrical conduction means comprises a slip ring assembly permitting rotation of one portion of the conduction means relative to another portion of the conduction means without twisting of the said portions of the electrical conduction means.

7. A cleaner as claimed in claim 6 characterised in that the slip ring assembly is adapted to permit 360 degree rotation of one portion relative to the other.

8. A cleaner as claimed in claim 7 wherein the slip ring assembly defines therein a slip ring air conduit for air- entrained vacuumed matter drawn from the nozzle towards the vacuum means .

9. A cleaner as claimed in claim 8 characterised in that the slip ring assembly comprises two spaced apart contact rings an two sliding contact members, one urged against one contact ring and the other urged against the other contact ring, the arrangement permitting relative sliding contact of the members and rings.

10. A cleaner as claimed in claim 9 wherein the slip ring assembly comprises treatment device activation means comprising a switch member operatively connected to the sliding contact members and movable to detach one or more of the contact members from one or more of the contact rings, thereby to break the electric circuit between the treatment device and the low voltage supply means.

11. A cleaner as claimed in any preceding claim characterised in that the electrical conduction means comprises a plug and socket combination comprising an external electrical connection point provided in a housing of the vacuum means, and a detachable flexible connector leading to a detachable air conduit which provides air communication with the nozzle.

12. A vacuum cleaner as claimed in claim 1 characterized in that the high voltage is greater than 100 volts .

13. A vacuum cleaner has claimed in either of the preceding claims characterized in that the vacuum means is driven by an alternating current operating at said high voltage .

14. A vacuum cleaner as claimed in any preceding claim, characterized in that the low voltage is not greater than 50 volts.

15. A vacuum cleaner has claimed in claim 4, characterized in that the low voltage is 24 volts.

16. A vacuum cleaner as claimed in any preceding claim, characterized in that the low voltage generation means comprises a transformer which steps the mains supply voltage down to a low voltage for powering said treatment device.

17. A vacuum cleaner as claimed in any preceding claim. characterized in that generation means for said low voltage may further comprise a rectifier for converting AC voltage to DC voltage.

18. A vacuum cleaner has claimed in any preceding claim, characterized in that the low voltage generation is effected by means of a second coil incorporated in an electric motor driving the vacuum means or from a tapping from the induction coil of the said electric motor.