A safety razor blade unit mounted for pivotal movement relative to a razor handle is biased to a normal rest position by a magnetic return force generated by a pair of magnets that are so disposed that the return force increases as the pivotal displacement of the blade unit from the rest position increases.
1. A safety razor comprising a handle and a blade unit, said blade unit comprising a guard, a cap and at least one blade, the blade unit being mounted to the handle for movement relative thereto about a pivot axis for following skin contours during shaving, the blade unit having a normal rest position towards which the blade unit is biased by a return force when pivoted away from the rest position, wherein the return force comprises a magnetic force generated by magnetic elements that are moved relative to each other in response to pivotal movement of the blade unit relative to the handle, and the return force increases in magnitude as the blade unit pivots away from the rest position.
2. A safety razor according to claim 1 , wherein the magnetic elements are arranged to generate a repulsive magnetic return force for urging the blade unit to the rest position.
3. The safety razor according to claim 2 , wherein said magnet elements comprise a first magnet and a second magnet, positioned with like poles facing each other.
4. The safety razor of claim 3 , wherein when said first magnet and said second magnet are moved towards each other as a result of the blade unit pivoting away from the rest position, a repelling force of increasing strength biases the blade unit to return to the rest position.
5. A safety razor according to claim 1 , wherein the blade unit has a frame with the guard and the cap thereon, and a first one of the magnetic elements is mounted to the underside of the frame adjacent the cap.
6. A safety razor according to claim 5 , wherein the first magnetic element cooperates with a second magnetic element for generating the magnetic return force.
7. A safety razor according to claim 6 , wherein an attachment member is provided for connecting the frame to the handle, the attachment member having the second magnetic element positioned thereon for cooperation with the first magnetic element positioned on the frame.
8. A safety razor blade unit according to claim 1 , wherein the pivot axis is positioned in front of the at least one blade.
9. A safety razor according to claim 1 , wherein the blade unit is pivotally carried by a pair of opposed arms extending from a hub, and a second one of the magnetic elements is positioned at the hub.
10. A safety razor according to claim 1 , wherein the pivot axis is located below a plane tangential to the guard and cap.
11. A safety razor according to claim 1 , wherein the rest position is defined by a stop face on the blade unit, the blade unit being pivotable in one direction only from the rest position.
12. A safety razor according to claim 1 , wherein as the angle of pivoting from the rest position increases, the spring rate characteristic of the magnetic return force increases smoothly.
13. A safety razor according to claim 1 , wherein at least one of the magnetic elements comprises an electromagnetic element.
14. A safety razor according to claim 13 , wherein a control device is provided for adjusting the magnetizing current delivered to the electromagnetic element.