In 1932 Mr Robert John filed a patent for a double blade safety razor. That is, he patented a razor that used two blades. Although, in hindsight, what he really patented was a unique blade design.
Doubling up the blade edges is a recurring idea. We looked at a few before, like Janos Oscar Plesch’s double double edged blade, Staats-Oels’ two blade double edged slant, a double double edged cartridge razor, and most recently Gillette’s disposable blade unit. So John wasn’t breaking new ground, although the way he wasn’t was novel.
It is worth recalling that the early thirties was a time of upheaval in the world of double edged razors. Gillette’s patent for the original three hole blade had expired, and slotted blades were the new hot thing. AutoStrop came out with the Probak, which became the Gillette Goodwill after a confusing merger in 1930.1 So while introducing a new double edge blade today would be madness, in the early thirties you might get away with it. Doubly so if it didn’t require a special razor, or the special razor also could use regular blades.
The blade, as described in the text and drawings, were mostly like other blades. Apart from a small ridge on one side, that is. The ridge meant that when two blades were placed back to back, there would be a small stand off between them. Thus by using two blades, your safety razor would become a double blade safety razor.2
Or, as the patent verbosely states it in one of the claims:
A safety razor blade having a cutting edge along each side, an elevated structure disposed 15 longitudinally and in close proximity to one cutting edge only, said blade being adapted to be employed in a clamping mechanism with a complemental blade having a similar formation whereby, when the clamping mechanism is tightened, the elevated portion of one blade is caused to separate the cutting edges along one side of the pair of blades and the elevated portion provided on the other blade is caused to separate the cutting edges along the opposite side of the blades.From US patent 2,044,698
One thing I do like is that Robert’s invention will work in any razor – or so he claims. It might work less well in a Old Type, unless the slot is modified to look more like a modern slotted blade.
There is a couple of interesting features built into the design. The geometry of the blade and razor head means that the cutting angle of the two blades will be slightly different.3 And there is alignment bumps built into the two blade tabs. This feature would make sure that the blades are parallel.
As so many other inventions, the double blade safety razor blades seems to have gone nowhere. In part this was likely because Robert would have to go up against Gillette and other big companies. And in part this was likely because there simply isn’t enough of a benefit to use four edges when two will do.
The full patent can be read at Google Patents.
- Seriously, you ought to follow that link and read it. It is the best and most complete overview of the merger that I’m aware of.
- Technically it would become a double blade double edge safety razor.
- See Fig 2, at 9 and 10.