Electric shaver

Abstract: An electric shaver comprises a housing (1) formed as a grip, a shaving head (2) comprising at least one cutting unit (11) having an outer cutting member (16) and an inner cutting member which is rotatable relative to the outer cutting member (16), and drive means for driving the inner cutting member, said shaving head (2) being pivotably connected to said housing (1). In known shavers the motor is accommodated in the shaving head, resulting in a poor balance and poor contact between the shaving head and the skin. According to the invention the shaver is characterised in that a motor (5) belonging to the drive means is accommodated inside said housing (1), said drive means being adapted to follow the pivotal movements of the shaving head (2) relative to the housing (1). Preferably, the drive means comprise flexible coupling means, for example a pulley-belt transmission (9, 12, 15) but alternatively the drive means may comprise a universal joint (17).

Description: The present invention relates to an electric shaver comprising a housing formed as a grip, a shaving head comprising at least one cutting unit having an outer cutting member and an inner cutting member which is rotatable relative to the outer cutting member, said shaving head being pivotably connected to said housing, and drive means for driving the inner cutting member comprising a motor with an output shaft mounted in said housing and flexible coupling means between the output shaft and the inner cutter member, said flexible coupling means being adapted to follow the pivotal movements of the shaving head relative to the housing. Such an electric shaver is known from US-A-2,194,815. In this document the coupling means comprise a flexible driving shaft. As a result, the shaving head can readily follow the contour of the skin in order to increase the shaving performance. However, a disadvantage of this known shaver is that a flexible driving shaft requires a relatively high power, especially when the shaving head is substantially parallel to the longitudinal axis of the housing, because in that position the flexible driving shaft is bent almost through an angle of 90° and causes therefore more friction. Moreover, to bend the flexible driving shaft through almost 90° a relatively large mounting space is required. The radius of the flexible driving shaft cannot be made too small. As a result, the height and especially the thickness of the shaver housing will be relatively large. Therefore, it is an object of the invention to provide an electric shaver whose shaving head is capable to readily following the contour of the skin, which requires comparatively less power and whose housing has a reduced thickness. In order to achieve the above object, according to the invention, an electric shaver according to the preamble of claim 1 is characterised in that said flexible coupling means comprises a pulley-belt transmission. This provides greater freedom in developing the various parts of the electric shaver. It enables the thickness of the housing to be reduced if the shaving surface of the shaving head is substantially coplanar with a main surface of the housing in the non-pivoted position of the shaving head relative to the housing. Contrary to the use of a flexible driving shaft which always has a transmission ratio of 1:1, a pulley-belt may have different transmission ratio by choosing different diameters of the pulleys. A further embodiment of the invention is characterised in that in a non-pivoted position of the shaving head relative to the housing an output shaft of the motor is substantially perpendicular to an axis of rotation of the rotatable inner cutting member, the drive means comprise bevel gears in driving engagement with the output shaft of said motor, and the pulley-belt transmission comprises a toothed pulley driven by one of the bevel gears, another toothed pulley for driving the inner cutting member, and a toothed belt between said toothed pulleys. The invention will now be described more detail, by way of example, with reference to the drawings, in which Fig. 1a is a diagrammatic perspective view of an electric shaver in accordance with the invention in a non-pivoted position of the shaving head, in which the axis of rotation of the inner cutting member is perpendicular to the motor shaft, Fig. 1b is a diagrammatic perspective view showing the electric shaver of Fig. 1a with the shaving head pivoted into an extreme position, Figs. 2a, 2b and 2c show a first embodiment of the invention having drive means comprising flexible coupling means in a diagrammatic plan view, in an elevational side view with the shaving head in a non-pivoted position, and in an elevational side view with the shaving head in a pivoted position respectively, Figs. 3a, 3b and 3c are diagrammatic views similar to those in Figs. 2a, 2b and 2c respectively, showing a second embodiment of the invention in which the drive means comprise flexible coupling means but in which the output motor shaft is oriented differently, and Fig. 1a shows an electric shaver comprising a flat housing 1 and a shaving head 2 in a non-pivoted position of the head, which is pivotably connected to the housing 1 by a hinge H, and Fig. 1b shows the electric shaver with the shaving head pivoted into an extreme position indicated in solid lines, the non-pivoted position of the shaving head, i.e. when the shaving head is not pressed against the skin, being indicated in broken lines. The shaving surface 2a of the shaving head, i.e. the outer surface of the outer cutting member, is substantially coplanar with one of the main surfaces 1a of the housing. Such an arrangement enables the thickness W2 of the housing of the shaver to be reduced to, for example, 15 mm. The shaving head 2 comprises two cutting units 3 each having an outer cutting member 16 and an inner cutting member (not shown) which is rotatable relative to the outer cutting member by means of a spindle, not shown, about an axis of rotation (11a, see Figs. 2, 3, 4). The cutting members of the cutting units define a shaving surface 2a of the shaving head 2, which shaving surface is substantially coplanar with one of the main surfaces 1a of the housing 1. A drive motor 5 for the cutting units is arranged inside the housing 1. When the shaver is not actually used for shaving the shaving head 2 is in the position shown in broken lines in Fig.1b. During shaving the force between the shaving head and the skin causes the shaving head to be pivoted against spring force and to assume a pivoted position as shown in solid lines in Fig.1b. A click mechanism may be provided to hold the shaving head 2 in the non-pivoted position. In a first embodiment shown in Figs. 2a, 2b and 2c a bevel gear 7 is mounted on a forward end of a rotary output shaft 6 of a motor 5, which shaft 6 extends parallel to a base plate 4 of the housing and parallel to the said main surface 1a of the housing. The bevel gear 7 is in mesh with a bevel gear 8, which is rotatably supported on a spindle projecting perpendicularly from the base plate 4. The bevel gear 8 carries a toothed pulley 9. The shaving head 2 comprises a base plate 10. The axes of rotation 11a of the rotatable inner cutting members of the two cutting units 11 extend perpendicularly to the base plate 10. Each cutting unit comprises a gear 14 meshing with a common drive gear 13 for the inner cutting members. Each cutting unit further comprises a toothed pulley 12. A toothed belt 15 is arranged between the toothed pulley 9 and the toothed pulley 12. The toothed pulleys 9 and 12 and the toothed belt 15 cooperate with each other to form flexible coupling means between the rotary output shaft 6 of the motor arranged inside the housing 1 and the spindles of the rotatable inner cutting members of the cutting units 11 arranged inside the shaving head. This arrangement ensures that, even if the shaving head 2 is inclined relative to the housing 1 as shown in Fig. 1b, the driving force of the motor is transmitted to the gears 14 of the respective cutting units 11 by the toothed pulleys 9 and 12 and the toothed belt 15 as shown in Fig. 2c. Thus, it is possible to drive inner cutting members inside outer cutting members 16 of the cutting units through expandable and pivotable spindles (not shown) provided on the respective gears 14. In a second embodiment shown in Figs. 3a, 3b, and 3c the motor 5A has a planar body with an output shaft 6A perpendicular to the base plate 4. The motor is secured to the base plate in an overhanging manner. A toothed pulley 9A is mounted directly on the output shaft 6A. A driving force is transmitted to a toothed timing pulley 12 in order drive the inner cutting members via a toothed belt 15. In the same way as in the first embodiment the toothed pulleys 9A and 12 and the toothed belt 15 cooperate with each other to form flexible coupling means between the rotary output shaft 6A of the motor arranged inside the housing and spindles of rotatable inner cutting members of the respective cutting units 11 arranged inside the shaving head.

Claims: An electric shaver comprising a housing (1) formed as a grip, a shaving head (2) comprising at least one cutting unit (11) having an outer cutting member (16) and an inner cutting member which is rotatable relative to the outer cutting member, said shaving head (2) being pivotably connected to said housing (1), and drive means for driving the inner cutting member comprising a motor (5) with an output shaft (6) mounted in said housing and flexible coupling means (15) between the output shaft (6) and the inner cutter member, said flexible coupling means being adapted to follow the pivotal movements of the shaving head (2) relative to the housing (1), characterised in that said flexible coupling means comprises a pulley-belt transmission (9,12,15). An electric shaver as claimed in claim 1, characterised in that in a non-pivoted position of the shaving head (2) relative to the housing (1) an output shaft (6) of the motor (5) is substantially perpendicular to an axis (11a) of rotation of the rotatable inner cutting member, the drive means comprise bevel gears (7,8) in driving engagement with the output shaft (6) of said motor (5), and the pulley-belt transmission (9,12,15) comprises a toothed pulley (9) driven by one (7) of the bevel gears (7,8), another toothed pulley (12) for driving the inner cutting member, and a toothed belt (15) between said toothed pulleys (9,12).

Inventors: ATSUMI YUKIHIKO, HISHIKI TERUO, ONODERA MAKOTO, ATSUMI, YUKIHIKO, HISHIKI, TERUO, ONODERA, MAKOTO, Atsumi, Yukihiko, c/o Int. Octrooibureau B.V., Hishiki, Teruo, c/o Int. Octrooibureau B.V., Onodera, Makoto, c/o Int. Octrooibureau B.V.
Applicants: PHILIPS ELECTRONICS NV, PHILIPS ELECTRONICS N.V.
Application year: 1992
Main classification: B26B19
IPC codes: B26B19