Linkage mechanism providing a virtual pivot axis for hair removal apparatus with pivotal head
View Patent ↗A linkage mechanism for a shaver or depilator has a head carrying at least one hair removal member mounted for rocking about a virtual axis that remains nearly static during pivoting. The linkage mechanism five links, which include a pair of spaced support arms pivoting on the head. A first transverse link member rotates about a third axis and pivots on each of the support arms. Second and third transverse link members pivot on the body and on respective ones of the support arms.
1. A linkage mechanism for a hair removal appliance having a head ( 1 ) carrying at least one hair removal member and mounted for rocking about a virtual axis, said linkage mechanism being mountable on an appliance body ( 2 ) and comprising:
a pair of spaced support arms ( 4 , 5 ) for pivotable attachment to the head ( 1 ) at first and second pivot axes ( 11 , 12 ), said first and second pivot axes being spaced apart by a first distance;
a first transverse link member ( 6 ) for pivotably mounting on said body ( 2 ) for rotation about a third axis ( 17 ) and being pivotably attached to each of said support arms ( 4 , 5 ), at fourth and fifth pivot axes ( 15 , 16 ) spaced apart by a second distance less than the first distance; and
second and third transverse link members ( 7 , 9 ) for pivotably mounting on the body ( 2 ) at respective first ends thereof and being pivotably attached at respective second ends thereof to respective ones of said support arms ( 4 , 5 ) at sixth and seventh pivot axes ( 13 , 14 ) spaced apart by a third distance, said first, second, third, fourth, fifth, sixth and seventh axes being mutually parallel.
2. A mechanism according to claim 1 , wherein said third distance is less than said first distance.
3. A mechanism according to claim 2 , wherein said third distance is less than said second distance.
4. A mechanism according to claim 2 , wherein said second distance is less than said third distance.
5. A mechanism according to claim 1 , wherein said respective first ends of the second and third transverse link members ( 7 , 9 ) are pivotally mounted on the body at eighth and ninth pivot axes ( 8 , 10 ) which are spaced apart, and parallel to said first and second axes.
6. A mechanism according to claim 5 , wherein a plane perpendicular to said parallel axes intersects said third, eighth and ninth axes ( 17 , 8 , 10 ) at spaced points forming an isosceles triangle.
7. A mechanism according to claim 5 , wherein said eighth and ninth axes ( 8 , 10 ) are colinear.
8. A mechanism according to claim 5 or 7 , wherein said third, eighth and ninth axes ( 17 , 8 , 10 ) and said virtual axis are parallel.
9. A mechanism according to claim 1 wherein the distance between said first and sixth axes ( 11 , 13 ) equals the distance between said second and seventh axes ( 12 , 14 ).
10. A mechanism according to claim 1 wherein the distance between said first and sixth axes ( 11 , 13 ) is greater than the distance between said second and seventh axes ( 12 , 14 ).
11. A mechanism according to claim 1 wherein the distance between said first and fourth axes ( 11 , 15 ) equals the distance between said second and fifth axes ( 12 , 16 ).
12. A mechanism according to claim 11 wherein the distance between said first and sixth axes ( 11 , 13 ) is less than the distance between said first and fourth axes ( 11 , 15 ) and the distance between said first and sixth axes ( 11 , 13 ) equals the distance between said second and seventh axes ( 12 , 14 ).
13. A mechanism according to claim 11 wherein the distance between said first and sixth axes ( 11 , 13 ) is greater than the distance between said first and fourth axes ( 11 , 15 ) and the distance between said first and sixth axes ( 11 , 13 ) equals the distance between said second and seventh axes ( 12 , 14 ).
14. A mechanism according to claim 11 wherein the distance between said first and sixth axes ( 11 , 13 ) is greater than the distance between said first and fourth axes ( 11 , 15 ), the distance between said second and seventh axes ( 12 , 14 ) is less than the distance between said second and fifth axes ( 12 , 16 ) and the distance between said first and sixth axes ( 11 , 13 ) is greater than the distance between said second and seventh axes ( 12 , 14 ).
15. A mechanism according to claim 1 , wherein the first, second and third transverse link members ( 6 , 7 , 9 ) are pivotably attached to said support arms by respective film hinges.
16. A mechanism according to claim 1 , wherein the second and third transverse link members are attached to the body by respective film hinges ( 8 , 10 ).
17. A mechanism according to claim 1 , wherein the second and third transverse link members are moveable relative to one another.
18. A mechanism according to claim 1 , wherein the support arms ( 4 , 5 ) are not parallel to one another.
19. A mechanism according to claim 1 , wherein the first transverse link member ( 6 ) is configured as a bell crank.
20. A linkage mechanism for a hair removal appliance having a head ( 1 ) carrying at least one hair removal member and mounted for rocking about a virtual axis generated by said linkage mechanism, said linkage mechanism being mountable on an appliance body ( 2 ) and comprising:
a pair of spaced support arms ( 4 , 5 ) pivotally connectable to the head ( 1 ) at first and second pivot axes ( 11 , 12 );
a first common link member ( 6 ) for pivotably mounting on said body ( 2 ) for rotation about a third axis ( 17 ) and being pivotably attached to each of said support arms ( 4 , 5 ), at fourth and fifth pivot axes ( 15 , 16 ); and
second and third transverse link members ( 7 , 9 ) for pivotably mounting on the body ( 2 ) at respective first ends thereof and being pivotably attached at respective second ends thereof to respective ones of said support arms ( 4 , 5 ) at sixth and seventh pivot axes ( 13 , 14 ).
21. A mechanism according to claim 20 , wherein the first, the fourth and the sixth axes ( 11 , 15 , 13 ) define a first set of three pivot axes and the second, the fifth and the seventh axes ( 12 , 14 ) define a second set of three pivot axes, and wherein the three pivot axes within at least one set of said first and second sets of pivot axes are co-planar.
22. A linkage mechanism for a hair removal appliance having a head ( 1 ) carrying at least one hair removal member and mounted for rocking about a virtual axis generated by said linkage mechanism, said linkage mechanism being mountable on an appliance body ( 2 ) and comprising:
first and second spaced support arms ( 4 , 5 ) for pivotally connecting to the head ( 1 ) at first and second pivot axes ( 11 , 12 );
a first common link member ( 6 ) for pivotably mounting to said body ( 2 ) for rotation about a third axis ( 17 ) and being pivotably attached to each of said support arms ( 4 , 5 ), at fourth and fifth pivot axes ( 15 , 16 ); and
at least one stabilizing link member ( 7 ) for pivotably mounting on the body ( 2 ) and being pivotably attached to only one of said first and second support arms ( 4 , 5 ).
23. A linkage mechanism according to claim 22 , further comprising a second stabilizing link member ( 9 ) for pivotably mounting on the body ( 2 ) at a first end thereof and being pivotably attached at a second end thereof to the other of said first and second support arms ( 4 , 5 ) at another pivot axis ( 14 ).
24. A hair removal apparatus, comprising:
the linkage mechanism according to claim 1 the head ( 1 ) carrying the at least one hair removal member supported on said linkage mechanism mounted on said body ( 2 ) for rocking about said virtual rocking axis.
25. A hair removal apparatus according to claim 24 , wherein said at least one hair removal member is a cutter unit for performing shaving.
26. A hair removal apparatus according to claim 24 , wherein said at least one hair removal member is an epilation head for plucking hair.
27. A method of mounting a component such as a head ( 1 ) carrying at least one hair removal member mounted, for rocking about a virtual axis, the method comprising the steps of:
pivotably attaching a pair of spaced support arms ( 4 , 5 ) to the head ( 1 ) at first and second pivot axes ( 11 , 12 ), said first and second pivot axes being spaced apart by a first distance;
pivotably mounting a first transverse link member ( 6 ) on a body ( 2 ) for rotation about a third axis ( 17 ) and pivotably attaching the first link member ( 6 ) to each of said support arms ( 4 , 5 ), at fourth and fifth pivot axes ( 15 , 16 ) spaced apart by a second distance less than the first distance; and
pivotably mounting second and third transverse link members ( 7 , 9 ) on the body ( 2 ) at respective first ends thereof and pivotably attaching the second and third link members at respective second ends thereof to respective ones of said support arms ( 4 , 5 ) at sixth and seventh pivot axes ( 13 , 14 ) spaced apart by a third distance, said first, second, third, fourth, fifth, sixth and seventh axes being mutually parallel.