Razor with in situ sensor

Abstract: A wet shave shaving system which contains an in situ sensor within the razor cartridge (10) or razor handle (30). The sensor (14,15) preferably comprises either a piezoelectric or a piezoresistive material which produces an electrical signal or resistance change when it is strained. In an active feedback system, the signal would be transferred from the cartridge (10) to the razor handle (30) where an electronically-active actuator would extend or retract as necessary to position the cartridge to produce a shave with a constant shave force. In a passive feedback system, the signal would be transferred from the cartridge to the handle where an electronically-activated element, such as an indicator light (41), would be activated to produce an indication to the user that he or she should reposition the razor to produce a constant shave force. In an alternative embodiment, the passive feedback system signal would provide an indication to the user that the blades are worm and the cartridge or razor should be replaced.

Description: This invention relates to the placement of one or more in situ sensors in razor heads, to produce a movement or indication to aid in the quality of the shave. The invention relates to a razor having an in situ sensor. Efforts to improve shave quality have been on-going for many years. Much of the effort to improve shave quality has been directed toward making razor cartridges and blades more responsive to the various forces encountered by the razor during shaving. Examples of the results include razor systems having movable components, such as blades, cartridges which flex or bend in response to shaving forces and blades which move inward and outward in response to those forces. One common thread between all previous shaving systems with movable components is that the movements are produced by the function of a mechanical element, such as a spring or pivot. Consequently, one limitation on the function of all of these prior razor systems is that they are only as sensitive as their mechanical elements. It would be advantageous to provide a razor system which did not depend upon mechanical elements for sensing the need for movement of the razor components but instead depended upon a more sensitive medium, such as an electronic sensor, to signal that the position of the razor cartridge or the cartridge itself needs changing. US-A-5165170 discloses a razor including an integral hair detection means that provides real-time feedback, during shaving, of areas of beard remaining to be shaved. The razor comprises a razor assembly mounted on a handle for brushing against the surface of a person's face and vibrating in response to contact with hairs thereon; a pickup coupled to the handle responsive to the vibrations produced therein for generating a corresponding signal; and audio frequency amplifying means within the handle for amplifying the signal from the pickup as an audio frequency output. The invention is defined, broadly, in independent Claims 1, 11, 12 and 13. Further, optional features of the invention are defined in the dependent claims. The present invention is directed to a wet shave shaving system which contains an in situ sensor within the razor cartridge. The sensor consists of a piezoelectric material which produces an electrical signal when it is strained. In an active feedback system, the signal would be transferred from the cartridge to the razor handle where an electronically-activated actuator would extend or retract as necessary to position the blades to produce a shave with a constant shave force. In a passive feedback system, the signal would be transferred from the cartridge to the razor handle where an electronically-activated element, such as an indicator light, would be activated to produce an indication to the user that he or she should reposition the razor to produce a constant shave force. In an alternative embodiment of the passive feedback system, the signal would provide an indication to the user that the blades are worn and should be replaced. Accordingly, it is an advantage of the present invention to provide a razor system having electronic sensors which provide a signal which produces movement to adjust the position of the blades or produces an indication to the user that the blades should be repositioned or replaced. There now follows a description of preferred embodiments of the invention, by way of example, with reference being made to the accompanying drawings in which: Figure 1 is a top view of a razor cartridge having an in situ sensor; Figure 2 is a cut-away view through line 2-2 of the razor cartridge having an in situ sensor; Figure 3 is a front view of an alternative embodiment of a razor cartridge having an in situ sensor; Figure 4 is a cut-away view through line 4-4 of the razor cartridge having an in situ sensor; Figure 4A is a top view of razor handle and a cut-away view of a razor cartridge having an in situ sensor in the handle; Figure 5 is top view of a razor handle and a cut-away view of a razor cartridge having an actuator adapted to receive signals from an in situ sensor in a razor cartridge; Figure 6a is a top view of a razor handle and cartridge having an actuator in a retracted position; Figure 6b is a top view of a razor handle and cartridge having an actuator in an unbiased position; Figure 6c is a top view of a razor handle and cartridge having an actuator in an extended position; Figure 7 is a top view of a razor handle and cartridge having an indicator light; Figure 8 is a top view of a razor handle and a cut-away view of a razor cartridge having a sliding potentiometer; and Figure 9 is a top view of a razor handle and a cut-away view of a razor cartridge having a potentiometer. Reference will now be made to the presently preferred embodiments of the invention. For the purpose of this application, wet shave razors are defined to be razors which are customarily utilized in conjunction with soap or shaving cream and hot water. The definition of wet shave razors includes both disposable razors, in which the user discards the entire unit after a certain number of uses, and permanent systems, with which the user discards and replaces the razor cartridge after a certain number of uses. In both instances, the razor head, or cartridge, is the portion which surrounds and contains the blade or blades. The combination of the razor head and the handle, either permanent or disposable, is defined as the razor system. The present invention provides for a wet shave razor head having one or more in situ sensors which receive and produce a response to the forces encountered by the razor head during shaving. The sensors are constructed from a piezoelectric material which produces an electrical signal when it is strained. A preferred piezoelectric polymer is polyvinylidene fluoride (PVDF) of the type sold by Amp Inc., Valley Forge, Pennsylvania. PVDF is especially preferred as a sensor because it is very flexible and provides a good, strong electrical signal. In addition, PVDF is commercially available in forms of various thickness which facilitates the processing of the material into a sensor which may be placed in virtually any location in a razor system. The piezoelectric polymer sensor is a film which is applied directly to or close to the blades within the razor head. Figures 1 and 2 illustrate cartridge 10 having two blades, 11, 12. The in situ sensor, in the form of a piezoelectric polymer film 14, 15, is coated on a portion of blades 11, 12 such that the film will be in a position to detect the result of the forces encountered during shaving and to provide an electrical signal based on those forces. Among the various forces which normally will be encountered are those which flex the cartridge upward or downward and those which produce stress and strain on the blade or blades. Means for transmitting the electrical signal from the in situ sensor to the receptor are also provided within the razor head. Preferably, such transmitting means comprise a conductive material, such as wire 18, which receives the electrical signal or signals from the sensor or sensors and then transmits the signals through the razor head to one or more receptors, which are preferably located within the razor handle. An alternative in situ sensor site is illustrated in Figures 3 and 4. In this embodiment, the in situ sensor is in the form of a solid piece of a piezoelectric material 23, preferably PVDF or a composite thereof, which is located between the two blades 21, 22. The sensor acts as a spacer to hold the two blades away from each other and at the same time detects the result of forces encountered during shaving. The location of the sensor in this embodiment is particularly useful for detecting forces acting on the razor head. The sensor generates an electrical signal from the forces transmitted through transmitting means 24 to one or more receptors which are preferably located within the razor handle. In a further embodiment, not forming part of the invention, the sensor may be positioned within the razor handle. In this embodiment, the sensor would indirectly measure the forces on the blade or blades which are transferred to the handle. A preferred embodiment of this alternative illustrated in Figure 4A employs a piezoresistive or piezoelectric sensor 51 which is placed in the handle 30. A movable piston 50 is placed in contact with the razor cartridge 52 or blades and translates the forces encountered during shaving to the sensor. Figure 5 illustrates the razor handle 30 of the present invention. The handle, in this case illustrated as a permanent system with a replaceable cartridge, comprises attachment means 32 for the attachment of the razor cartridge, piston 31, conductor 34 and a receptor which is illustrated in Figure 5 in the form of electric motor 38. Upon the placement of a razor head on the handle, either permanently or replaceably, conductor 34 is connected to the transmitting means of the razor head to form a circuit and receive the in situ sensor signal through the transmitting means. For disposable razors, the transmitting means of the razor head and the conductor may be a single unit. For permanent systems, the connection is accomplished by placing connectors on the exposed ends of the transmitting means and the conductor so that they attach to each other upon the placement of a razor head on the handle. As with the transmitting means of the razor head, the conductor may be constructed from any suitable conductive material, such as copper wire. Two different preferred embodiments of receptors exist for receiving and processing the in situ sensor signal and one or more receptors may be employed in each preferred embodiment. The first receptor embodiment is an active system in which the receptor is in the form of a simple signal processing circuit which processes the in situ sensor signal and produces a response to move and position the blades. In the preferred embodiment, the receptor is a signal processing circuit in conjunction with an actuator which is used to move and position the piston 31. While the actuator may be any means for sufficiently moving the piston, as illustrated the actuator is preferably lead screw 36 which is driven by electric motor 38 in series with coupling device 37. The piston 31 or a portion of the piston is threaded and rides along the lead screw as the motor responds to the feedback signal generated by the signal processing circuit in response to the in situ sensor. Conductor 34 transmits the electrical signal from the in situ sensor to the signal processing circuit to complete the electrical circuit. Based on the motor's response to the in situ sensor signal, lead screw 36 rotates and piston 31 correspondingly extends and retracts as necessary to flex the razor head to position the razor head to produce a consistent shave. As illustrated in Figures 6a, 6b and 6c, the expansion of the piston 31 will flex the razor head 35 into a convex shape while the retraction of the piston will flex the razor head into a concave shape. The second preferred receptor embodiment, illustrated in Figure 7, is a passive system. In this embodiment one or more sensors, conductors and transmitting means between the razor head and the handle may be as in the previous embodiment. In this embodiment, the receptor in handle 40 does not produce motion but instead is a signal processing circuit which activates an indicator, such as light 41. The receptor in the passive system may also activate a light emitting diode (LED) or any other desired indicator. The signal processing circuit receives the electrical signal from the in situ sensors and activates an indicator, such as a light, which provides the user with a visual signal that he or she should take some action. For example, the in situ sensor may be used to differentiate that the user is exerting too much or too little pressure during shaving by generating a comparable electrical signal that would produce a visual indication to the user to change the shaving pressure. In addition. because blades dull over time and thus require more pressure to cut hair, the evolution of additional shaving pressure may be used to indicate that either the disposable razor should be discarded or, in a permanent system, that the razor head should be replaced. In an alternative embodiment, the voltage may be used to activate a device such as a motor or piezoelectric transducer to produce a motion, such as a vibration, or to activate an electric circuit on a circuit board or solid state chip which produces an audible sound, such as notes of a song and/or a human-like voice. In a further alternative embodiment, the passive system may be combined with the active system. For example, the receptor may activate an actuator to produce a constant shave pressure while at the same time lighting an indicator to indicate that the blades are worn and need replacing. Further alternative embodiments, not forming part of the invention, of an in situ sensor comprising a potentiometer are illustrated in Figures 8 and 9. The potentiometer detects changes in the forces applied to the blades upon transfer to the potentiometer shaft. Movement of the potentiometer shaft via a translation, as in a sliding potentiometer, or rotation, as in a potentiometer, results in a change in resistance indicative of the forces applied to the blades. Changes in resistance may be converted into an equivalent voltage change and utilized to activate a device. In the embodiment of Figure 8, sliding potentiometer 60 is located in handle 30. Potentiometer shaft 61 of the sliding potentiometer receives forces from the blades through the shaving cartridge 63 via piston 62. The change in resistance resulting from the movement of the potentiometer shaft along the sliding potentiometer may be converted into an equivalent voltage change and utilized to activate an actuator or indicator or some other device which will movably respond or produce a visual indication to the user. In the embodiment of Figure 9, a potentiometer 70 is located in handle 30. Forces encountered during shaving arc translated via piston 73 to lever 72 and then onto potentiometer shaft 71. As with the previous embodiment, the translation of the forces will cause the potentiometer to produce a resistance change which may be converted to an equivalent voltage and utilized to activate an actuator or visual indicator in response to the applied shaving forces. In an altemative embodiment, a combination of receptors may be employed such that either multiple active responses arc produced, multiple passive responses arc produced, or a combination of active and passive responses are produced. While there have been described what are presently believed to be the preferred embodiments of the present invention, those skilled in the art will realize that various changes and modifications may be made to the invention without departing from the invention.

Claims: A razor system comprising a razor head, having one or more blades (11, 12; 21, 22) and a handle (30; 40), wherein the razor head further comprises one or more in situ sensors for producing one or more signals based on forces encountered during shaving, each of the in situ sensors consisting of piezoelectric material (23) in the form of a polymer film (14, 15) which is directly applied to one or more of the one or more blades (11, 12; 21, 22), the handle (30, 40) further comprising one or more receptors (3 8) for receiving the one or more signals from the one or more in situ sensors and wherein conducting means (18, 34) extend from the one or more in situ sensors to the receptor (38) to provide an electrical circuit between the one or more in situ sensors and the one or more receptors (38). A razor system according to Claim 1, wherein the in situ sensors consist of polyvinylidene fluoride. A razor system according to any preceding claim, wherein the one or more receptors (38) comprise a signal processing circuit which receives the one or more signals. A razor system according to Claim 3, wherein the signal processing circuit is connected to an actuator (31) and wherein the signal processing circuit produces a response to the one or more signals which drives an actuator (31) to move the razor head or the one or more blades (11,12; 21,22) to provide consistent pressure on a surface being shaved. A razor system according to Claim 3 or Claim 4 wherein the signal processing circuit is connected to an indicator which produces an indication in response to a feedback signal. A razor system according to Claim 5, wherein the indicator comprises a light (41), a light emitting diode, a sound producing device, a motion producing device, or any combination thereof. A razor system according to Claim 6, wherein the indicator provides a signal to a user that one or more blades (11,12; 21,22) are worn and need replacement. A razor system according to Claim 6 or Claim 7, wherein the indicator provides a signal to a user that the user should apply a different pressure to the razor during shaving. A razor system according to any preceding claim, wherein the razor head is permanently attached to the handle (30; 40). A razor system according to any of Claims 1 to 8, wherein the razor head is removably attached to the handle (30; 40). A razor system comprising a razor head, having at least two blades (11,12; 21,22) and a handle (30; 40), wherein the razor head further comprises one or more in situ sensors for producing one or more signals based on forces encountered during shaving, each of the one or more in situ sensors consisting of piezoelectric material (23) and being in the form of a spacer (23) located between two of the at least two blades, and the handle (30, 40) further comprising one or more receptors (38) for receiving the one or more signals from the one or more in situ sensors and wherein conducting means (18, 34) extend from the one or more in situ sensors to the receptor (38) to provide an electrical circuit between the one or more in situ sensors and the one or more receptors (38). A razor head having one or more blades (11,12; 21,22) and one or more in situ sensors for producing a signal based on forces encountered during shaving, each of the in situ sensors consisting of piezoelectric material (23) in the form of a polymer film (14, 15) which is directly applied to one or more of the one or more blades (11,12; 21,22). A razor head having at least two blades (11,12; 21,22) and one or more in situ sensors for producing a signal based on forces encountered during shaving, each of the in situ sensors consisting of piezoelectric material (23) and being in the form of a spacer (23) located between two of the at least two blades. A razor head according to Claim 12 or Claim 13, wherein the in situ sensors consist of polyvinylidene fluoride. A razor system according to Claim 1, wherein the one or more receptors (38) comprise a signal processing circuit which produces a feedback signal in response to the in situ sensor signal. A razor system according to Claim 15, wherein the signal processing circuit is connectable to an actuator (31) and wherein the signal processing circuit produces a response to at least one in situ sensor signal which drives the actuator (31). A razor system according to Claim 15 or Claim 16, wherein the receptor (38) comprises a signal processing circuit and an indicator which produces a feedback signal in response to at least one in situ sensor signal. A razor system according to Claim 17, wherein the indicator comprises a light (41), a light emitting diode, a sound producing device, a motion producing device, or any combination thereof. A razor system according to Claim 18, wherein the indicator provides a signal to a user that the one or more blades (11,12; 21,22) are worn and need replacement. A razor system according to Claim 18 or Claim 19, wherein the indicator provides a signal to a user that the user should apply a different pressure to the razor during shaving.

Inventors: ORLOFF GLENNIS J, ORLOFF, GLENNIS J.
Applicants: WARNER LAMBERT CO, WARNER-LAMBERT COMPANY LLC
Application year: 1998
Main classification: B26B21
IPC codes: B26B21