A guard of a safety razor blade unit has a lubricating strip ( 24 ) disposed in front of a backstop ( 23 ), and the edge of the backstop which contacts the skin during shaving is castellated to define channels ( 30 ) separated by lands ( 31 ). The channels ( 30 ) enable an effective layer of lubricant to remain on the skin until the blade positioned to the rear of the backstop contacts the skin in the course of a shaving stroke.
1. A safety razor blade unit, comprising: a frame supporting a plurality of blades with parallel cutting edges on a front portion of the blades; and a guard disposed in front of the cutting edges of the blades, the guard comprising a lubricating element for delivery of lubricant to the skin during shaving, and a backstop having an upper surface disposed between the blades and the lubricating element and disposed to contact the skin during shaving, wherein the skin contacting upper surface of the backstop is interrupted by one or more channels running from the lubricating element toward the blades to facilitate the passage of lubricant to the blades during shaving.
2. A blade unit according to claim 1 , wherein the backstop includes a plurality of said channels separated by lands forming said skin contacting upper surface.
3. A blade unit according to claim 2 , wherein the channels are not more than 3 mm wide.
4. A blade unit according to claim 3 , wherein the channels are at least as wide as the lands.
5. A blade unit according to claim 2 , wherein the lands and channels are arranged alternately along the backstop at a uniform pitch.
6. A blade unit according to claim 2 , the guard further including an elastomeric strip disposed forwardly of the backstop.
7. A blade unit according to claim 6 , wherein the lubricating element is disposed between the elastomeric strip and the backstop.
8. A blade unit according to claim 6 , wherein the elastomeric strip has up standing projections thereon.
9. A blade unit according to claim 8 , wherein the upstanding projections are tubular with open ends.
10. A blade unit according to claim 9 , wherein the tubular projections are D-shaped in cross section and oriented with their flat faces directed away from the backstop.
11. A blade unit according to claim 1 , wherein the channel depth is in the range of 0.1 to 2 mm.
12. A blade unit according to claim 11 , wherein the channel depth is in the range of 0.3 to 0.8 mm.
13. A blade unit according to claim 12 , wherein the channels one of more have substantially upright side walls and a substantially flat bottom wall.
14. A blade unit according to claim 1 , including an elastomeric strip disposed forwardly of the backstop.
15. A blade unit according to claim 14 , wherein the lubricating element is disposed between the elastomeric strip and the backstop.
16. A blade unit according to claim 14 , wherein the elastomeric strip has upstanding projections thereon.
17. A blade unit according to claim 16 , wherein the upstanding projections are tubular with open ends.
18. A blade unit according to claim 17 , wherein the tubular projections are D-shaped in cross section and oriented with their flat faces directed away from the backstop.
19. A blade unit according to claim 1 , wherein the skin contacting upper surface of the backstop is defined by elastomeric material.
20. A blade unit according to claim 1 , wherein the lubricating element is located immediately in front of the backstop and has an upper surface disposed at a level intermediate the bottom of the one of more channels and the skin contacting upper surface of the backstop.