GB2038691A - Electric razor - Google Patents

Abstract

An electric razor having a helical cutting blade (9) rotatable with a shaft (18) mounted parallel to the motor- drive shaft (14) and rotated about its longitudinal axis by a drive belt and pulley system 15, 16, 17 has an elongate trimmer (24) mounted on a housing cover 3. The trimmer is reciprocated longitudinally by means of a worm gear (22) meshed with a gear wheel (21) at one end of the blade shaft, the worm gear having an eccentrically mounted stud (23) at one end which is engaged in a slot (26) in a trimmer slide (27) the slot extending perpendicular the longitudinal axis of the trimmer. <IMAGE>

Description

SPECIFICATION Electric razor The present invention relates to an electric razor.

More particularly, the present invention is concerned with an electric razor of the type having a part-cylindrical, perforated foil-head enclosing a cutter blade which is closely-spaced from the foilhead and driven by an electric motor housed within the body of the razor.

According to the present invention there is provided an electric razor comprising a housing carrying a part-cylindrical perforated foil and a blade mounted within the foil with its cutting edge closely spaced therefrom, the blade being connected to be rotated about the longitudinal axis of the foil by an electric motor within the housing, and the blade and the perforations being so arranged that the blade slices hairs projecting through the perforations in use, the razor further including an elongate trimmer for trimming beard and sideboard hairs, arranged to be reciprocated longitudinally by the motor.

The present invention thus provides a razor having a comfortable, smooth shaving action due to the slicing rather than chopping action of the blade and the protection of the blade by the foil, and also provides a trimmer for the longer hairs. The trimmer preferably extends parallel the axis of the perforated foil head and projects through a slit in the housing adjacent the head.

The drive connection from the motor to the trimmer is preferably readily disengageable such that the trimmer may be connected to be driven by the motor only when it is actually required by the user.

The trimmer is preferably driven by a simple drive mechanism including a worm gear carrying an eccentrically mounted stud at one end, the stud being engaged in a slot or groove in the trimmer which extends perpendicular the longitudinal axis thereof to transmit reciprocating motion to the trimmer on rotation of the worm gear about its longitudinal axis; thus rotation of the worm gear causes rotation of the stud which is free to move in the trimmer slot in the direction perpendicular the axis of the trimmer but drives reciprocating movement of the trimmer along its axis.

The worm gear preferably receives drive from a gear wheel connected to be driven by the motor; the gearwheel may, for example, be one of a set of meshed gear wheels or may be mounted directly on the motor drive shaft. In a preferred embodiment, however, in which the blade of the razor is mounted on a shaft connected to be rotated by the motor, the said gearwheel is mounted for rotation with the blade shaft. The drive to the trimmer is preferably disengageable by disengagement of the worm gear from the said gear wheel.

The cutting blade of the razor according to the present invention preferably comprises a metal strip which is wound helically around a central shaft, such that the blade extends radially outwardly from the shaft, the cutting edge being formed between radial and circumferential faces of the blade. The blade may have several helical blade portions each of which is formed with an outer cutting edge although preferably only a single, continuous blade is provided which is formed as a helix with a small pitch compared with its radius. A helical blade may, however, be formed in other ways.

The blade shaft may be an extension of the drive shaft of the motor but since the resulting razor would be elongate and inconvenient to handle the shaft preferably extends parallel to the motor drive shaft, the shaft and blade, and also the trimmer, being located alongside the motor. The blade shaft may be connected to be driven by the motor by any suitable means but is preferably rotated by means of a drive belt engaged with respective drive wheels carried by the two shafts, the geat wheel and worm gear forming the drive for the trimmer conveniently being provided at the opposite end of the blade shaft from the drive belt.The use of a drive belt and pulley system for rotating the blade together with the power take-off for the trimmer from the blade shaft rather than directly from the motor allows the motor and associated electrical circuit to be housed in a sealed portion of the razor housing from which only that end of the drive shaft carrying the drive wheel protrudes. The opening for the drive shaft is preferably provided with a sealed bearing to prevent dust and hairs from penetrating the motor which may be battery-operated and/or provided with a lead for connection to a mains supply.

The foil may be removable from the housing to allow access to the blade but is preferably carried by a cover portion of the housing which is removable to allow access to the blade and drive belt and also to the trimmer drive mechanism. The blade and the drive belt are preferably readily removable to allow for their replacement when worn.

As a safety feature fo preventing rotation of the blade while the cover is removed, the cover preferably has an electrical contact which completes the electrical circuit for the razor motor on fitting of the cover to the sealed portion of the housing, the circuit being broken when the cover is removed.

One embodiment of the invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevational view of an electric razor according to the invention shown with a cover detached: Figure 2 is an end elevational view of the razor of Figure 1 without the cover, and Figure 3 is a perspective view, on an enlarged scale, of a trimmer drive mechanism of the razor of Figures 1 and 2.

An electric razor, generally indicated 1, is shown in Figure 1 ofthe drawings and has a hollow body 2 and a hollow cover 3, shown detached from the body, and defining the head of the razor. The cover 2 and the body 3 are formed from a plastics material, adjacent edges of the cover and body walls, in the assembld razor, being formed with cooperating elements which are snap-engageable to attach the cover 3 to the body 2; the body and cover are readily disengageable to allow dismantling of the razor for cleaning and maintenance.

The assembled razor 1 has a substantially pearshaped cross-section, as seen from the end view of Figure 2, being wider at the base 4 of the body 2 to facilitate holding of the razor, in use, and narrower at the head to fit the contours of the user's face. The cover 3 incorporates a part-cylindrical, perforated foil 5 which is stamped from sheet metal and extends axially of the razor.

The body 2 of the razor houses an electric motor 13, the drive shaft 14 of which extends axially of the razor 1. An electrical lead 6 for connection to a mains supply for operating the motor 13 enters the base of the body 2 through a sealed aperture, the electrical circuit (not shown in detail) for the motor being housed in the sealed base portion of the body 2. An ontoffswitch 7 for the motor, of known sliding type, is located on one end wall of the body 2.

One end of the drive shaft 14 of the motor 13 extends through a sealed opening in an axiallyrecessed end wall 8 of the body 2 opposite that end carrying the switch 7 and is provided with a first drive wheel 15 engaged by an endless drive belt 16.

The belt 16 is of circular cross-section and is also engaged with a second drive wheel 17 carried at one end of a cutter drive shaft 18 which extends parallel to the shaft 14 and is mounted in an upper portion of the body 2, coaxial with the foil-head 5 in the assembled razor. The cover 3 of the razor 1 has an integral tongue portion 3a which extends from the head down that end of the razor carrying the wheels 15, 17 and the belt 16 to enclose these drive members, in use.

The cutter drive shaft 18 is mounted adjacent its end carrying the wheel 17 in a seat 19, in the body 2 formed as a half-shell bearing block, the shaft being retained in the seat 19 by the tension of the belt 16.

The opposite end of the shaft 18 is mounted in a seat 20, which is formed as a full shell bearing block and which encloses that end of the cutter drive shaft 18.

The cutter drive shaft 18 has an enlarged central portion 11 between the seats 19, 20 which carries a cutter blade 9. The blade 9 comprises a single, flat, elongate metal strip which is wound on to the shaft in a helix having a pitch which is narrow compared with its radius, the inner edge of the blade being secured to the shaft portion 11. The outer edge 10 of the blade 9 is ground such that it forms a substantially cylindrical surface which is closely spaced from the foil 5 in the assembled razor and has a cutting edge 12 at the acute-angled junction between the edge 10 and a face of the blade 9.

The complete cutter assembly, that is, the shaft 18 and blade 9, can easily be removed from the razor 1 by disengaging the belt 16 from the wheel 17 and removing the shaft 18 from its seats 19, 20.

In use of the assembled razor 1, with the lead 6 connected to the mains and the switch 7 switched to operate the motor 13, drive is transmitted from the drive shaft 14 via the wheels 15, 17 and drive belt 16 to rotate the shaft 11 and blade 9. If the foil-head is placed against the user's face, hairs project through the perforations into the path of the cutting edge 12 of the blade, the blade being driven such that the cutting edge is inclined at an acute angle to its circumferential direction of motion and slices the hairs.

The helical blade also acts as an auger to transport the cut hairs which fall into the head, the direction of motion being such that the hairs move towards the drive belt 16 and fall to a collection point 30 beneath the wheel 15. This allows the hair to be emptied easily from the razor after use on removal of the cover 3.

The cover 3 is provided with an electrical-contact maker (not shown) which is positioned so as to complete the electrical circuit between the switch 7 and the motor 13 at a safety contact 28 when the cover 3 is correctly attached to the base 2, the circuit being broken when the cover 3 is removed to prevent operation of the razor 1.

Referring to Figures 1 and 3 of the drawings, a toothed gear wheel 21 is mounted on the cutter drive shaft 18 at its end adjacent the complete-shell bearing block 20 for driving a trimmer generally indicated 24 which is mounted in the cover 3 and projects through an elongate slot 25 in the cover 3 beneath the foil head 5.

As shown in Figure 3, in the assembled razor the gearwheel 21 engages a worm gear 22 which extends transverse the axis of the shaft 18 and carries an eccentrically mounted stud 23 at its end adjacent the trimmer 24. The stud 23 is engaged in a slot 26 at one end of a plastics slide 27 for operating the trimmer, the stud being free to move transverse the axis of the slide in the slot 26, while lateral movement of the stud on rotation of the worm gear 22 by the wheel 21 causes axial, reciprocating motion of the slide 27, and hence of the trimmer blades, to operate the trimmer 24.

The slot 26 is open at its end adjacent the body 2 of the razor to allow removal of the cover 3 and trimmer 24 from the body 2, the worm gear being carried by the body 2, and to permit displacement of the worm gear 22 to disengage it from the gear wheel 21 when the trimmer 24 is not required for use. For this latter purpose, the stud 23 projects through an aperture 29 in the cover 3 and is manually operable to displace the worm gear into and out from engagement with the gear wheel 21.

The razor described thus makes use of a simple and robust operating mechanism within a compact housing of a type favoured by the consumer. The actual size of the housing will depend on the chosen size of motor, a larger motor being more reliable and easierto wire up during manufacture; since the motor is housed with its axis parallel to the blade axis a relatively large motor can be incorporated within a housing which is comfortable to hold and easy to manipulate.

Since the razor is robust and intended to last for a substantial length of time, the housing is preferably formed with a pleasing design and/or colour combination. Certain parts, such as the blade and drive belt, will, however, require replacement at intervals and may be designed to wear out substantially simuitaneously or at different time intervals. For example, those parts of the blade shaft 18 which contact the bearings 19,20 are preferably sheathed in a plastics material having substantially the same life as the blade itself such that the whole blade unit must be replaced; the bearings 19,20 may be made of a harder plastics material which need not be replaced and may be integral with the body 2.

The wheels 15, 17 are preferably also of plastics material but of a harder material than the belt 16 such that only the belt must be replaced at intervals.

The materials are chosen to give the required friction to drive the belt 16 without excess tension which might damage the motor 13.

The foil 5 may be flexible or rigid and may be fixed in the cover 3 or readily removable.

Claims (11)

1. An electric razor comprising a housing carrying a part-cylindrical perforated foil and a blade mounted within the foil with its cutting edge closely spaced therefrom, the blade being connected to be rotated about the longitudinal axis of the foil byan electric motor within the housing and the blade and the perforations being so arranged that the blade slices hairs projecting through the perforations in use, the razor further including an elongate trimmer for trimming beard and sideboard hairs arranged to be reciprocated longitudinally by the motor.

2. An electric razor as claimed in Claim 1, in which the mechanism for transmitting drive from the motor to the trimmer is readily disengageable.

3. An electric razor as claimed in Claim 1 or Claim 2, in which the drive for the trimmer includes a worm gear carrying an eccentrically mounted stud at one end, the stud being engaged in a slot in the trimmer extending perpendicularthe longitudinal axis thereof to transmit reciprocating motion thereto on rotation of the worm gear about its longitudinal axis.

4. An electric razor as claimed in Claim 3, in which the blade is mounted on a shaft connected to be driven by the motor, the blade shaft carrying a gear wheel engageable with the worm gear of the trimmer drive to rotate the worm gear about its longitudinal axis, in use.

5. An electric razor as claimed in Claim 4 as dependent on Claim 2, in which the worm;,5aear is manually displaceable transverse the axisJof the blade shaft into and out from engagement with the gear wheel.

6. An electric razor as claimed in Claim 4 or Claim 5, in which the blade shaft extends parallel to, and alongside, the motor drive shaft, the shafts being provided with respective drive wheels at their adjacent ends with which a drive belt for transmitting drive from the motor to rotate the blade shaft is engaged, the gear wheel for transmittihg drive to the trimmer being provided at the opposite knd of the blade shaft from the drive wheel.

7. An electric razor as claimed in Claim 6, in which the motor is housed in a sealed portion of the housing, the end of the drive shaft carrying the drive wheel projecting through a sealed bearing in the housing wall.

8. An electric razor as claimed in Claim 7, in which the perforated foil and the trimmer are mounted in a cover portion of the housing which is disengageable from the sealed housing portion to allow access to the drivemechanisms for the blade and the trimmer.

9. An electric razor as claimed in Claim 8, in which the cover has an electrical contact which completes the electrical circuit for the razor motor on fitting of the cover to the sealed portion of the housing, the circuit being broken when the cover is removed.

10. An electric razor as claimed in any of Ciaims 4 to 9, in which the blade comprises a metal strip wound helically around the blade shaft such that it extends radially outwardly from the shaft, the cutting edge being formed between radial and circumferential faces of the blade.

11. An electric razor substantially as herein described with reference to, and as shown in the accompanying drawings.