Electric shaver with longitudinally split cutter

Claim 2

An electric shaver comprising: at least two movably mounted members having respective masses (M1, M2), at least one of said members comprising a movable inner cutter cooperating with an outer foil and the other of said members comprising a counterweight, said counterweight being at least partly recessed into said movable inner cutter; driven means including a motor coupled to and reciprocatingly driving said two members respectively in antiphase; support means including mountings coupled to and resiliently supporting each of said at least two members, each mounting including a spring, the spring constants (K1, K2) of the mounting springs being selecTed in relation to the masses (M1, M2) of the respective members so that Square Root K1/M1 is substantially equal to Square Root K2/M2, so that at least two members have substantially the same natural frequency of reciprocation and the counterweight compensates for vibrations; said motor being operable under power to drive both of said movable members substantially continuously at a frequency of reciprocation substantially equal to said natural frequency.

Claim 3

An electric shaver according to claim 1, wherein said mountings support both of said members for linear reciprocation.

Claim 4

An electric shaver according to claim 1, wherein said inner cutter is split longitudinally of the direction of linear reciprocation.

Claim 5

An electric shaver according to claim 1, wherein the centre of mass of the counterweight reciprocates on a path substantially collinear with the path of reciprocation of the centre of mass of the cutter.

Claim 6

An electric shaver according to claim 1, wherein the motor is a vibratory battery operated motor having at least one reactive system including a permanent magnet and a cooperating coil connected through a control circuit to the battery, the magnet being mounted on one member and the coil on the other.

Claim 7

An electric according to claim 5, including one or more reactive systems wherein coils are mounted on the movable members and the magnet or magnets on a fixed part of the shaver.

Claim 8

An electric shaver according to claim 5, wherein two parts of the one or more reactive systems are respectively housed, at least in part, within the two movable members.

Claim 9

An electric shaver according to claim 1, wherein the motor has a rotary output shaft for driving a crank shaft having a pair of crank throws relatively positioned to drive said at least two movable members in antiphase.

Claim 10

An electric shaver according to claim 1, wherein the mounting for each member comprises a pair of leaf springs having at least two arms projecting from a common root, at least one arm being secured at its free end to the respective member and at least one arm being secured at its free end to a fixed part of the shaver.

Claim 11

An electric shaver according to claim 1, wherein the mounting for the at least two members comprises a single pair of leaf springs having at least two arms projecting from a common root, at least one arm being secured at its free end to one member and at least one other arm being secured at its free end to another member.

Claim 12

An electric shaver according to claim 1, wherein said motor is a battery powered motor.

Claim 13

An electric shaver according to claim 1, wherein said at least two members are arranged to be driven in parallel reciprocation.

Claim 14

An electric shaver according to claim 12, wherein said at least two members are further arranged to be driven in non-aligned paths.

Claim 15

An electric shaver comprising: at least two movably mounted members having respective masses (M1,M2), at least one of said members comprising a movable inner cutter cooperating with an outer foil and the other of said members comprising a counterweight; drive means including a motor coupled to and reciprocatingly driving said two members respectively in antiphase; support means including mountings coupled to and resiliently supporting each of said at least two members, each mounting including a spring, the spring constants (K1,K2) of the mounting springs being selected in relation to the masses (M1, M2) of the respective members so that Square Root K1/M1 is substantially equal to Square Root K2/M2, so that the at least two members have substantially the same natural frequency of reciprocation and the counterweight compensates for vibrations; said motor being operable under power to drive both of said movable members substantially continuously at a frequency of reciprocation substantially equal to said natural frequency, said motor compRising a vibratory battery operated motor having at least one reactive system including a permanent magnet and a cooperating coil connected through a control circuit to the battery, the magnet being mounted on one member and the coil on the other.

Claim 16

An electric shaver comprising: at least two movably mounted members having respective masses (M1,M2), at least one of said members comprising a movable inner cutter cooperating with an outer foil and the other of said members comprising a counterweight; drive means including a motor coupled to and reciprocatingly driving said two members respectively in antiphase; support means including mountings coupled to and resiliently supporting each of said at least two members, each mounting including a spring, the spring constants (K1,K2) of the mounting springs being selected in relation to the masses (M1, M2) of the respective members so that Square Root K1/M1 is substantially equal to Square Root K2/M2, so that the at least two members have substantially the same natural frequency of reciprocation and the counterweight compensates for vibrations; said motor being operable under power to drive both of said movable members substantially continuously at a frequency of reciprocation substantially equal to said natural frequency, said motor compRising a vibratory battery operated motor having at least one reactive system including a permanent magnet and a cooperating coil connected through a control circuit to the battery, the magnet being mounted on one member and the coil on the other.

Claim 17

An electric shaver according to claim 14 wherein said cutter and counterweight are mounted for linear reciprocation.

Claim 18

An electric shaver according to claim 14, including one or more reactive systems wherein coils are mounted on the movable members and the magnet or magnets on a fixed part of the shaver.

Claim 19

An electric shaver according to claim 14, wherein two parts of the one or more reactive systems are respectively housed, at least in part, within the two movable members.

Claim 20

An electric shaver according to claim 14, wherein the motor has a rotary output shaft for driving a crank shaft having a pair of crank throws relatively positioned to drive said at least two movable members in antiphase.

Claim 21

An electric shaver according to claim 14, wherein the mounting for each member comprises a pair of leaf springs having at least two arms projecting from a common root, at least one arm being secured at its free end to the respective member and at least one arm being secured at its free end to a fixed part of the shaver.

Claim 22

An electric shaver according to claim 14, wherein the mounting for the at least two members comprises a single pair of leaf springs having at least two arms projecting from a common root, at least one arm being secured at its free end to one member and at least one other arm being secured at its free end to another member.

Claim 23

An electric shaver according to claim 14, wherein said inner cutter is split longitudinally of the direction of linear reciprocation.

Claim 24

An electric shaver comprising: at least two movably mounted members having respective masses (M1,M2), at least one of said members comprising a movable inner cutter cooperating with an outer foil and the other of said members comprising a counterweight; drive means including a motor coupled to and reciprocatingly driving said two members respectively in antiphase; support means including mountings coupled to and resiliently supporting each of said at least two members, each mounting including a spring, the spring constants (K1,K2) of the mounting springs being selected in relation to the masses (M1,M2) of the respective members so that square root K1/M1 is substantially equal to square root K2/M2, so that the at least two members have substantially the same natural frequency of reciprocation and the counterweight compensates for vibrations, said cutter and counterweight being supported and driven such that the centre of mass of the counterweight reciprocates on a path substantially collinear with the path of reciprocation of the centre of mass of the cutter; said motor being operable under power to drive both of said movable members substantially continuously at a frequency of reciprocation substantially equal to said natural frequency.

Claim 25

An electric shaver comprising: at least two movably mounted members having respective masses (M1,M2), at least one of said members comprising a movable inner cutter cooperating with an outer foil and the other of said members comprising a counterweight; drive means including a motor coupled to and reciprocatingly driving said two members respectively in antiphase; support means including mountings coupled to and resiliently supporting each of said at least two members, each mounting including a spring, the spring constants (K1,K2) of the mounting springs being selected in relation to the masses (M1,M2) of the respective members so that square root K1/M1 is substantially equal to square root K2/M2, so that the at least two members have substantially the same natural frequency of reciprocation and the counterweight compensates for vibrations, said cutter and counterweight being supported and driven such that the centre of mass of the counterweight reciprocates on a path substantially collinear with the path of reciprocation of the centre of mass of the cutter; said motor being operable under power to drive both of said movable members substantially continuously at a frequency of reciprocation substantially equal to said natural frequency.

Claim 26

An electric shaver according to claim 22 wherein said cutter and counterweight are mounted for linear reciprocation.

Claim 27

An electric shaver according to claim 22 wherein said inner cutter is split longitudinally of the direction of linear reciprocation.

Claim 28

An electric shaver according to claim 22, wherein the motor is a vibratory battery operated motor having at least one reactive system including a permanent magnet and a cooperating coil connected through a control circuit to the battery, the magnet being mounted on one member and the coil on the other.

Claim 29

An electric shaver according to claim 25, including one or more reactive systems wherein coils are mounted on the movable members and the magnet or magnets on a fixed part of the shaver.

Claim 30

An electric shaver according to claim 25, wherein two parts of the one or more reactive systems are respectively housed, at least in part, withiN the two movable members.

Claim 31

An electric shaver according to claim 25, wherein the motor has a rotary output shaft for driving a crank shaft having a pair of crank throws relatively positioned to drive said at least two movable members in antiphase.

Claim 32

An electric shaver according to claim 25, wherein the mounting for each member comprises a pair of leaf springs having at least two arms projecting from a common root, at least one arm being secured at its free end to the respective member and at least one arm being secured at its free end to a fixed part of the shaver.

Claim 33

An electric shaver according to claim 22, wherein the mounting for the at least two members comprises a single pair of leaf springs having at least two arms projecting from a common root, at least one arm being secured at its free end to one member and at least one other arm being secured at its free end to another member.