HAIRDRYERS

Abstract: A hairdryer incorporates a housing (11) which in turn contains an electric heater element (13) and a control switch or control switches for the hairdryer. An electric motor (35) for the hairdryer drives a fan (41) which blows air through the heater element to result in a stream of heated air. The motor is mounted in a casing (38) which is removable from the housing (11) and is electrically connected to the rest of the hairdryer by plugs (52, 53) and sockets (28, 29) which automatically engage and disengage as the casing is assembled to the housing. This arrangement allows a burnt out motor to be replaced very simply.

Description: Hairdryers BACKGROUND TO THE INVENTION The invention relates to hairdryers. A conventional hairdryer incorporates an electrical heater element, a fan to provide an air current over the heater element and an electric motor to drive the fan. These essential components are normally mounted in a common housing which incorporates a handle and appropriate controls. Smaller and lighter hairdryers are becoming popular as they are easier to handle than larger hairdryers and also there is a tendency to use a heater element of higher power to increase the effectiveness of the hairdryer. One feature which helps in the provision of a small and lightweight hairdryer is the use of a simple permanent magnet DC electric motor.. Small and compact lightweight DC motors are readily available at low cost. A low voltage DC motor can be used in conjunction with a normal mains supply voltage by making use of the invention disclosed in U.K. Patent 1,100,823 or the equivalent U.S. Patent 3 ? 3^8,020. A simple lightweight motor installed in a small housing close to a high output heater element tends to have a service life which is sufficient for a domestic hairdryer. However, hairdryers used by pro¬ fessional hairdressers - which are known as professional hairdryers - require a much longer service life than a domestic hairdryer and the expected life of a simple DC motor is normally inadequate for a professional hairdryer. Replacement of a faulty motor is normally a time consuming operation requiring a high degree of skill and special tools such as soldering irons so it is not normally practical to replace the motor as a matter of routine service by the user of the hairdryer. An object of the present invention is to provide a hairdryer which can be satisfactory for use as a professional hairdryer despite the fact that it uses a simple low cost electric motor with a limited life. SUMMARY OF THE INVENTION According to the present invention there is provided hairdryer incorporating a housing, an electric heat element, an electric motor and a fan arranged to be driven the motor to blow air over the heater element to an outle characterised in that the electric motor is removeable fr the housing and incorporates electrical connections which a automatically made as the motor is inserted into position a are automatically broken as the motor is removed. Th enables a user of the hairdryer to replace a burnt out otherwise unserviceable motor. Preferably the fan is mounted directly on the mot shaft and is removeable with the motor. The fan itself m be a simple low cost item so it can be preferable to repla the fan than to provide for disconnection of the fan from t motor. Preferably the motor is mounted in a casing and t casing is removeable from the housing with the electr motor. The provision of a separate casing with the mot allows a simple connection to be designed between housing a casing regardless of the details of the motor. Preferably the casing comprises an inner casing close surrounding the motor, an outer casing and vanes between t inner and outer casing supporting the inner casing and mot within the outer casing. Th s arrangement provides convenient air flow path round the motor. Preferably the inner casing and vanes are removeab from the outer casing with the motor so that the motor, inn casing and vanes are replaced when the motor is replaced a the original outer casing can be re-used. Preferably there are alignment guides operative as the housing and casing are assembled together in order to align the electrical connections with each other. The alignment guides may be portions of the vanes projecting from the outer casing and corresponding guides in the interior of the housing. The housing may incorporate a main body including the heater element and also incorporates a handle portion projecting laterally from the heater element having controls for the hairdryer and wherein the motor is mounted in a casing which includes a rear handle portion arranged to co¬ operate with the first mentioned handle portion to form a complete handle.The mains connecting lead to the hairdryer may lead into the handle so that it is accessible for connection and disconnection when the casing with its rear handle portion is removed. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings? Figure 1 is a cross sectional view of the complete hairdryer in its assembled condition; Figure 2 is a front elevation of the hairdryer; Firure 3 is a view corresponding to Figure 1 but showing the ha.-dryer more diagram atically and in its disassembled conditi-n; and Figure 4 is a perspective view of internal parts of the hairdryer in the disassembled condition. DESCRIPTION OF PREFERRED EMBODIMENT The hairdryer shown- in the drawings incorporates a housing 11 which may be moulded from tough plastics material. The housing incorporates a generally axial portion 12 which is of circular cross section and is tapered from a lar diameter at its rear end to a smaller diameter at the fr end. The forward part of the housing carries a conventio electric heater element 13. " The heater element comprises cruciform support formed from heat resisting sheet materi In particular the support comprises an upright sheet mem 15 and two transverse interlocking sheet members 16. series of notches 17 are spaced out along an elongated rec 18 at all four extremities of the cruciform. The recess serve to receive a coiled wire heater coil 14 which is wo in a helix around the cruciform and the notches serve locate and space apart the individual convolutions of element. A shroud 19 of heat resistant material surrou the heater coil and also serves to strengthen the crucifor The heater element also incorporates a conventional ther cut-out 21 which is arranged to break the electrical circ through the heater coil if the local temperature rises abo an acceptable level. The heater element 13 is secured in t housing 11 between a front end closure 22 and a print circuit board 23 both of which will be described in furt detail. The closure 22 incorporates a series of radial circumferential ribs 24 as best seen in Figure 2 and is su that air can flow freely through it but fingers of a us cannot penetrate into the heater element. The closure 23 secured in position by a wedge action and possibly also means of an adhesive or by positive engagement of inte locking lugs. The printed circuit board 23 carries several electric components and connections for the hairdryer including t power supply to the heater element. The circuit board also carry a bridge rectifier to produce DC from AC. Detai of the electrical compoments and connections are a matter choice dependent on the type of circuitry and contro required for the hairdryer and so are not shown in detai OM The printed circuit board is secured to the upright 15 of the cruciform by means such as rivets at 25 and 26 and this mechanical connection may also serve as the electrical connection between the circuit board and the heater element. The printed circuit board 23 is secured in an accurately pre¬ determined position within the housing by means such as guide grooves 27 in the interior of the housing= The printed circuit board also carries two socket members 28 and 29 best seen in Figure 4 which are intended for connection to the electric motor as will be described in further detail subsequently. The housing also has a handle portion 31 incorporating an electrical switch assembly 32. The switch assembly may be a simple on-off switch or may be a more complex switch assembly such as a slow-off-fast switch and a separate hot- warm switch. The switch assembly constitutes a control for the hairdryer. The handle portion of the housing also carries a terminal block 33 by means of which a mains lead 34 which extends from the base of the handle is connected to the hairdryer. A small compact electric motor 35 is provided and is preferably in the form of a permanent magnet DC motor. The motor is supported in an inner casing 36 best seen in Figure 4 which is formed integrally with four radial vanes 37. The vanes 37 are provided to support the motor in an outer casing 38. The outer casing 38 is generally cylindrical and in the assembled hairdryer forms a rearward extension of the housing 11. Lugs 39 projecting outwardly from the outer edge of the vanes 37 and locate in corresponding notches in the inner surface of the outer casing 38 and thus serve to locate the motor 35 accurately within the outer casing. The motor drives an axial flow fan 41 which is secu directly to the motor output shaft 42. Air propelled by fan enters the outer casing through an end grille 43 flows over the motor between the inner and outer casings. The outer casing 38. also incorporates a handle port 44 which co-operates with the handle portion 31 of housing to form a completely closed handle. In the assemb condition of the hairdryer, as shown in Figure 1, the han portion 44 closes off the access to the switch assembly and also closes off access to the terminal block 33 for mains connection. However, when the casing is removed shown in Figure 3» access to these components is availabl The casing 38 is secured to the housing 11 by means three screws. One of these screws 45 is shown clearly in handle in Figure 1. The other screws 46 and 47 associated with lugs 48 and 49 respectively which are for partly on the housing and partly on the outer casing. addition to securing the housing to the casing, these l act as support brackets which enable the hairdryer to supported in a stand. The forward end of the motor 35 carries an insulat board 51 which carries two electrical connection pins 52 53 which are electrically connected through to the mo itself. In the assembled hairdryer, the pins 52 and engage in the sockets 28 and 29 on the printed circuit bo 23 to establish an electrical connection to the motor. order to ensure that the pins engage in the sockets, it necessary to guide the casing 38 accurately with respect the housing 11. This is achieved by alignment gui constituted by forwardly extending parts of the vanes which engage in grooves such as continuations of the groo 27 for the printed circuit board 23. It is a simple mat for an operator to ensure that these guides are prope engaged with each other as the housing and casing are mo together and this ensures that the accurately positioned pins and sockets automatically come into correct engagement. In use, the controls are set to give a suitable motor and fan speed and a suitable heat output from the - heater element and the fan blows air through the heater element so that the heated air flows out of the front end .of the hairdryer. If the motor 35 burns out or otherwise ceases to function, the thermal cut-out 21 prevents the heater element from overheating. It is then a simple matter to disconnect the hairdryer from the mains supply, unfasten the three screws 45, . 46 and 47 and thereby separate the casing from the housing. The motor 35 comes away from the housing with the outer casing 38. The motor 35, fan 41, inner casing 36 and vanes 37 can then be removed as a unit from the outer casing and discarded. A similar new unit is then inserted in the outer casing and the outer casing is again joined to the housing by the three screws. The hairdryer is then fully serviceable again. As a practical commercial matter, it may be desirable to sell each hairdryer with a replacement motor unit and to suggest to the user that a new motor unit should be ordered to provide a new spare unit as soon as the first spare unit has had to be brought into use. _OMPI

Claims: CLAIMS 1. A hairdryer incorporating a housing, an electric heate element, an electric motor and a fan arranged to be driven b the motor to blow air over the heater element to an outlet characterised in that the electric motor is removeable fro the housing and incorporates electrical connections which ar automatically made as the motor is inserted into position an are automatically broken as the motor is removed. 2. A hairdryer as claimed in Claim 1 wherein the fan i mounted directly on the motor shaft and is removeable wit the motor. 3. A hairdryer as claimed in Claim 1 or Claim 2 wherein th motor is mounted in a casing and the casing is removeabl from the housing with the electric motor. 4. A hairdryer as claimed in Claim 3 wherein the casin comprises an inner casing closely surrounding the motor, a outer casing and vanes between the inner and outer casin supporting the inner casing and motor within the oute casing. 5. A hairdryer as claimed in Claim 4 wherein the inne casing and vanes are removeable from the outer casing wit the motor so that the motor, inner casing and -≡ es ar replaced when the motor is replaced and the original oute casing can be re-used. 6. A hairdryer as claimed in any preceding claim includin alignment guides operative as the housing and casing ar assembled together in order to align the electrica connections with each other. 7. A hairdryer as claimed in Claim 6 wherein the alignmen guides are portions of the vanes projecting from the oute casing and corresponding guides in the interior of the housing. 8. A hairdryer as claimed in any preceding claim wherein the housing incorporates a main body including the heater element and also incorporates a handle portion projecting laterally from the heater element having controls for the hairdryer and wherein the motor is mounted in a casing which includes a rear handle portion arranged to co-operate with the first mentioned handle portion to form a complete handle. 9. A hairdryer as claimed in Claim 8 wherein the mains connecting lead to the hairdryer leads into the handle and is accessible for connection and disconnection when the casing with its rear handle portion is removed.

Inventors: DYERHUGH E
Applicants: DYERHUGH E, FIRTH CLEVELAND LTD
Application year: 1979
Main classification: A45D20
IPC codes: A45D20, F04D25