WO2000001513A1

WO2000001513A1 - Electric shaver with an oscillating shaver head

Info

Publication number: WO2000001513A1
Application number: PCT/NL1999/000410
Authority: WO
Inventors: Johan Godefroy
Original assignee: Topical Research V.O.F.
Priority date: 1998-07-01
Filing date: 1999-07-01
Publication date: 2000-01-13
Also published as: AU4803399A; NL1011668C2

Abstract

An electric shaver has a shaver head (5) that can execute an oscillating motion around an imaginary eccentric axis (9). In order to create a larger shaving surface while the width of the electric shaver remains the same, the connection between the suspension and the shaver head is at distance from the imaginary eccentric axis (9). In an embodiment the suspension exists of two slots (23, 25) on each transverse side of the shaver head (5) and two pins (27, 29) which extend into the slots and are fixed to the housing of the electric shaver. The slots (23, 25) are bent along a circle whose midpoint is located on the imaginary axis (9).

Description

Electric shaver with an oscillating shaver head.

BACKGROUND OF THE INVENTION:

Field of the invention

The invention relates to an electric shaver with an oscillating shaver head that oscillates around an imaginary eccentric axis and is suspended in the housing of the electric shaver, which shaver head comprises a cutting plate as well as cutting elements that can execute a back and forth motion along the cutting plate, with drive elements present in the housing along with a transmission mechanism that converts the drive motion into the back and forth motion of the cutting elements along the cutting plate and into the oscillating motion of the shaver head. Due to the eccentric oscillating motion of the shaver head during shaving the skin is pressed away in relation to the hairs such that the hairs are cut off closer to the root than if this oscillating motion were absent.

Prior art

Such an electric shaver is known from the American patent specification

3.401.454 (of which the text and drawings are included in this description by this reference). The suspension of the shaver head in the housing is formed in this known electric shaver by a bearing at the site of the oscillating shaft on each transverse side of the shaver head. The bearing takes up space in the lengthwise direction of the shaver head such that the length of the effective part of the cutting plate (this is the part behind which the knives are located) is limited in relation to the total width of the electric shaver.

Summary of the invention

An objective of the invention is to produce an electric shaver of the type mentioned in the preamble in which the shaving surface is larger than that of the known electric shaver while the width of the electric shaver remains the same, or in which the same shaving surface is achieved as that of the known electric shaver with a smaller width of the electric shaver. To this end the electric shaver according to the invention is characterised by the fact that the suspension and the shaver head is at a distance from the imaginary eccentric axis. Thus the suspension can be placed under the cutting elements instead of alongside the cutting elements, such that the length of the effective shaving surface is not limited by the suspension.

An embodiment of the electric shaver according to the invention is characterised by the fact that the suspension of the shaver head in the housing on each transverse side of the shaver head comprises at least one slot as well as at least one pin, that is at least partly extended into the slot, such that the pin and the slot can be moved in relation to each other, and in which the slot is bent along a circle whose midpoint is located on the oscillating axis. Preferably the suspension has two slots and two pins on each transverse side of the shaver head, with the slots being located in the shaver head and the pins being fastened to the housing. A further embodiment of the electric shaver according to the invention is characterised by the fact that the suspension comprises at least two oblong elements which are with one end connected to the housing and with the other end to the shaver head.

Yet a further embodiment of the electric shaver is characterised by the fact that the elements are hingedly connected with the housing and/or the shaver head. Again a further embodiment of the electric shaver is characterised by the fact that the elements are flexible and are with at least one end fixedly connected to the housing and/or the shaver head.

A further prefered embodiment of the electric shaver is characterised by the fact that the shaver head is connected to the housing via four elements, two of them at each transverse side of the shaver head, which elements are fixedly connected to the housing and hingedly connected with the shaver head.

In the known electric shaver it is usual that the electric shaver is pressed against the skin. This presses in the skin such that the favourable effect of the oscillating shaver head, this being the pressing away of the skin in relation to the hairs, is limited. One embodiment of the electric shaver according to the invention that increases this favourable effect of the oscillating shaver head is characterised by the fact that the electric shaver comprises at least one support element that is located above the cutting plate and that extends lengthwise from it and of which the position along the cutting plate is adjustable. During shaving this support element is pressed against the skin and the cutting plate comes in contact with the skin such that the skin is pressed in less than if the support element were absent, such that the depth effect (this is cutting off the hairs under the skin) of the oscillating motion of the shaver head increases. Preferably the support element comprises a rotating roller. The support element can be adjusted to acquire, depending on the skin condition, an optimal amount of pressure through the oscillating shaver head, such that the hairs are cut off at the deepest point. Preferably the electric shaver has two support elements, one on each side of the shaver head. It should be remarked that the embodiments with the support element can also be used apart from the suspension construction with slots and pins and also offers advantages separately and that specifically the option exists to also protect this embodiment separately, independently of the above characteristics and embodiments, in a patent application being filed independently of the one at hand. The construction of the drive mechanism of the known electric shaver is subject in many areas to wear, such that play is created, something which results in a decreased shaving effect. A further embodiment of the electric shaver according to the invention in which this disadvantage is not present is characterised by the fact that the transmission mechanism for converting a revolving drive motion of the motor into a back and forth motion of the cutting elements comprises a transmission element that contains a bearer that reciprocates along a guide to which near each end a strip, stiff in a lengthwise direction and flexible in a direction perpendicular to that, is fastened that extends in a direction toward the middle of the bearer and is fastened with the other end tangentially to a bush, in which an eccentric pin can rotate that is coupled with the drive elements. This yields an advantageous construction that is not, or only minimally, subject to wear. In order to increase the flexibility of the drive preferably the bearer has two more flexible strips on it whose free ends, preferably in a flexible manner, are coupled with the cutting elements. An advantage of this construction is that possible vibrations caused by the drive elements are absorbed by the extra flexible strips. It is remarked that the embodiments with the transmission mechanism can also be used separately from the suspension construction with slots and pins and separately from the support element, and also offer advantages separately and that specifically the possibility is maintained of protecting these embodiments separately, independently of the above mentioned characteristics and embodiments, in a patent application being filed independently of the one at hand.

Another disadvantage of the known electric shaver is when shaving sensitive areas of the skin, for example at the site of a wound, pain can be caused by the oscillating motion of the shaver head. Another embodiment of the electric shaver according to the invention in which this disadvantage can be avoided is characterised by the fact that the electric shaver has a switch for switching on and off the oscillating motion of the shaver head. Due to the possibility of being able to turn off the oscillating motion sensitive parts of the skin can also be shaved without the oscillating motion causing pain. Preferably the electric shaver comprises an uncoupling mechanism that can uncouple drive elements of the drive working together for the oscillating motion in order to switch off the oscillating motion of the shaver head.

Here, too, it should be remarked that the embodiments in which the oscillating motion can be switched on and off can also be utilised separately from the suspension construction with slots and pins and separately from the support element and the transmission mechanism, and also offer advantages separately from these and that specifically the possibility is maintained of protecting these embodiments separately, independently from the above mentioned characteristics and embodiments, in a patent application being filed independently of the one at hand.

The invention also relates to a shaver head and a transmission element for application in the electric shaver according to the invention.

Brief description of the drawings

The invention will be elucidated more fully below by means of drawings in which embodiments of the electric shaver according to the invention are shown. In these drawings:

Figure 1 shows a cross-section of an embodiment of the electric shaver according to the invention;

Figure 2 shows a first embodiment of the suspension of the shaver head in the electric shaver; Figure 3 shows a second embodiment of the suspension of the shaver head in the electric shaver;

Figure 4 shows the support elements present in the electric shaver; Figure 5 shows a cross-section of the transmission element of the electric shaver for switching from a rotating to a reciprocating motion; and

Figure 6 shows a bottom view of the transmission element.

Detailed description of the drawings

Figure 1 shows a cross-section of an embodiment of the electric shaver according to the invention. The electric shaver 1 has a housing 3 and a shaver head 5. The shaver head 5 can execute an oscillating motion 7 around a virtual eccentric axis 9 (see figure 2). The shaver head 5 has a cutting plate 11 and cutting elements that are formed by a number of knives 13 present on a knife bearer 14. The knives 13 can pass the cutting plate 11 making a back and forth motion 15. In the housing 3 there are drive elements formed by a motor 17 and a transmission mechanism 19, that converts the drive motion of the motor 17 into the back and forth motion 15 of the knives 13 along the cutting plate 1 1 and into the oscillating motion 7 of the shaver head 5. The shaver head 5 is suspended via pen-slot constructions in the housing 3. This suspension 21 is shown in more detail in figure 2. In the shaver head

5 in each transverse side there are two slots 23 and 25. These slots 23 and 25 are bent along circles whose midpoints are located on the axis 9. The suspension 21 also comprises two pins 27 and 29 on each transverse side of the shaver head 3 whose ends are located in the slots 23 and 25. The shaver head 5 is made to oscillate via a drive rod 61 of the transmission mechanism. Through the axis 9 that is eccentric from the shaver head the shaving effect along the circumference of the cutting plate 11 is not equal everywhere. The greatest oscillating motion occurs at A, specifically from point A to Al. This motion catches the longest beard hairs. The radial component A1-A2 of this motion will press the skin in somewhat. The skin is maximally pressed in at the motion from point B to B 1 , specifically with a radial effect of B1-B2. The skin is pressed in least from point C to CI , specifically with the radial effect of C1-C2, which is to be recommended on a surface that is not soft, such as generally around the jaw and chin. Figure 3 shows another embodiment of the suspension of the shaver head in the housing. The shaver head 5 is connected to the housing 3 via four flexible elements, two elements 26 and 28 near each transverse side of the shaver head 5. The flexible elements

26 and 28 are fixedly connected to the housing 3 and are hingedly connected to the shaver head 5.

The electric shaver also has two moveable support elements, on each side of the shaver head one, as shown in figure 4. Each support element 31, 32 has a rotating roller 33, 34 fastened by means of brackets 35, 36 to a strip 37, 38. The strips 37 and 38 can be shifted in guides 39 and 40. On the strips 37 and 38 there are operating cams 41 and 42 with which the strips can be shifted.

The transmission mechanism 19, see figure 1 , for converting a rotating drive motion of the motor 17 into the back and forth motion 15 of the knives 13 comprises a transmission element 43 that can reciprocate along a guide 50. The transmission element 43 has a bearer 45 to which two vertical strips 47 and two horizontal strips 49 are fastened. The strips 47 and 49 are stiff lengthwise and flexible in a direction perpendicular to that.

The horizontal strips 49 have free ends coupled flexibly with the knife bearer 14. The vertical strips 47 are tangentially fastened to a bush 51 in which a rotatable pin 53 is present. This pin 53 is situated eccentrically on a motor shaft 55 of the motor 17.

In figures 5 and 6 the transmission element 43 is shown in cross-section and from below in more detail. The pin 53 makes a circular motion 57 in relation to the transmission element 43. Because the guide 50 (see figure 1) limits the freedom of motion of the transmission element 43, the guide element can make only a reciprocating motion 59. This bends the strips 47 in a direction perpendicular to the motion 59 during the circular motion 57 of the pin 53. Because the strips 47 are stiff in a lengthwise direction, the circular motion 57 of the pin 53 is converted into the reciprocating motion 59 of the transmission element. With this transmission element 43, therefore, an advantageous construction has been created for converting a continually rotating motion into an up and down reciprocating motion.

The drive of the shaver head 5, with which this executes an oscillating motion, is now further explained on the basis of figure 1. The transmission mechanism 19 is provided with a drive rod 61 that is hinged to the shaver head 5. This drive rod 61 makes a back and forth motion 63 and is driven to do this by an eccentric pin 67 rotating around a shaft 65. This shaft 65 runs through a hollow shaft 69 on which there is a gear 71. The shafts 65 and 69 can be coupled with each other by pressing discs 73 and 75, that are on the two shafts, under pressure from a spring 77 against each other. The gear 71 is continually linked with toothing present on a part of the motor shaft 55. In the position shown the discs 73 and 75 are uncoupled from each other because the shaft 65 has been pressed away against the pressure of the spring 77. This presses away a guide element 79 on the end of the shaft 65 by a guide 83 connected with a switch 81. With this switch 81 the oscillating motion of the shaver head 5 can be switched on and off . The discs 73 and 75, thus, form together with the shaft 65 and spring 77, and with the guide element 79 and guide 83, an uncoupling mechanism that can uncouple the drive elements of the drive working together for the oscillating motion in order to switch off the oscillating motion of the shaver head.

Although in the above the invention is explained on the basis of the drawings, it should be stated that the invention is in no way limited to the embodiments shown in the drawings. The invention also extends to all embodiments deviating from the embodiments shown in the drawings within the context defined in the claims. It is possible, for example, to connect the elements of figure 3 fixedly to the shaver head and hingedly to the housing, or fixedly both to the shaver head and the housing, or hingedly both to the shaver head and the housing. The suspension may be formed by only two flexible elements which extend over a large part of the length of the shaver head. It is also possible to have only one slot and pin and one element on each transverse side of the shaver head. Further it is possible to only have one slot and one pin on each transverse side of the shaver head, such that the end of the pin that is located in the slot is then not round but has a curved form that is situated in a sliding manner in the slot, such that the shaver head cannot turn around the pin but can only move according to the path of the slot. In addition, the transmission element can also be made without horizontal arms such that the bearer is then coupled directly and flexibly with the knife bearer. Also only a single support element can be used and the other can be left out and the support element need not comprise a rotating roller. In addition, the knifes can be replaced by a blade that is comparable with the cutting plate but whose openings have sharp edges that work as knives, with the blade then making a back and forth cutting motion along the cutting plate.

Claims

CLAIMS:

1. Electric shaver with an oscillating shaver head that oscillates around an imaginary eccentric axis and is suspended in a housing of the electric shaver, which shaver head comprises a cutting plate as well as cutting elements that can make a back and forth motion along the cutting plate, with drive elements located in the housing and a transmission mechanism that converts the drive motion into the back and forth motion of the cutting elements along the cutting plate and into the oscillating motion of the shaver head, characterised in that the suspension and the shaver head is at a distance from the imaginary eccentric axis.

2. Electric shaver according to claim 1 , characterised in that the suspension of the shaver head in the housing has at least one slot on each transverse side of the shaver head as well as at least one pin, that extends at least partly into the slot, with the pin and the slot being moveable in relation to each other, and in which the slot is bent along a circle whose midpoint is located on the oscillating axis.

3. Electric shaver according to claim 2, characterised in that the suspension on each transverse side of the shaver head has two slots and two pins, with the slots being located in the shaver head and the pins fastened to the housing.

4. Electric shaver according to claim 1 or 2, characterised in that the suspension comprises at least two oblong elements which are with one end connected to the housing and with the other end to the shaver head.

5. Electric shaver according to claim 4, characterised in that the elements are hingedly connected with the housing and/or the shaver head.

6. Electric shaver according to claim 4 or 5, characterised in that the elements are flexible and are with at least one end fixedly connected to the housing and/or the shaver head.

7. Electric shaver according to claim 4, 5 or 6, characterised in that the shaver head is connected to the housing via four elements, two of them at each transverse side of the shaver head, which elements are fixedly connected to the housing and hingedly connected with the shaver head.

8. Electric shaver according to one of the preceding claims, characterised in that the electric shaver comprises at least one support element that is located above the cutting plate and extends lengthwise from it, and of which the position is adjustable along the cutting plate.

9. Electric shaver according to claim 8, characterised in that the support element comprises a rotating roller.

10. Electric shaver according to one of the preceding claims, characterised in that the transmission mechanism for converting a rotating drive motion of the motor into a back and forth motion of the cutting elements comprises a transmission element that contains a bearer that reciprocates along a guide to which near each end a strip, stiff in a lengthwise direction and flexible in a direction perpendicular to that, is fastened that extends in a direction toward the middle of the bearer and is fastened with the other end tangentially to a bush, in which an eccentric pin can rotate that is coupled with the drive elements.

11. Electric shaver according to claim 10, characterised in that two more flexible strips are fastened to the bearer whose free ends are coupled with the cutting elements.

12. Shaver head for application in an electric shaver according to one of the preceding claims, which shaver head comprises a cutting plate as well as cutting elements that can make a back and forth motion along the cutting plate, characterised in that on each transverse side of the shaver head at least one slot is present, with the slot being bent along a circle whose midpoint is located on the oscillating axis.

13. Shaver head according to claim 12, characterised in that on each transverse side of the shaver head there are two slots.

14. Transmission element for converting a rotating motion into a back and forth motion for application in an electric shaver according to claim 10 or 11, characterised in that the transmission mechanism comprises a transmission element that contains a bearer that reciprocates along a guide to which near each end a strip, stiff in a lengthwise direction and flexible in a direction perpendicular to that, is fastened that extends in a direction toward the middle of the bearer and is fastened with the other end tangentially to a bush, in which an eccentric pin can rotate.

15. Transmission element according to claim 14, characterised in that on the bearer there are two more flexible strips for coupling with the cutting element.