Is your brush too soft? To stiff? Ever wanted a brush that could be either? If that is the case, Anton Hopfen’s improved shaving brush is what you need. Patented in 1878, it was not only capable of adjusting the loft and backbone on the fly, but also held the shaving soap.
Interestingly enough, the adjustable loft wasn’t the main point of the invention. To quote the patent text:
The nature of my invention consists in the construction of a handle for shaving-brushes, which form a receptacle for the shaving-soap or other articles, as will be hereinafter more fully set forth.US patent 206,791
In other words the adjustable brush was more of an afterthought. A bright idea tacked on to a dim idea, seen in hindsight.
The handle does look rather awkward in the patent drawing. A tubular handle, with a box for soap tacked on. Granted, the patent does state that the soap holder could be unscrewed – but even so it looks unwieldy. I can see the utility of having my soap at hand while shaving when I face lather… but the modern shaver likely prefer having it separated from the brush.
The adjustable brush on the other hand might be marketable today as well. The brush was mounted on a platform that was slid up and down the tube, held in place with a spring loaded friction lock. Moving it out made the brush softer and with a higher loft. To quote:
It is, of course, understood that the farther the brush is projected from the handle the softer it will he in use, and hence the adjustability of the brush in the handle is of great importance.US patent 206,791
The mechanism is detailed in figure 4, consisting of a pair of spring loaded arms and a platform. Figure 5 shows how the brush was held in place on the platform with a specially formed metal bracket (F) engaging a grove. Interestingly enough, this do mean that the brush heads would be easily replaceable.
The patent is available to read at Google Patents. If you enjoy reading about old patents and other shaving oddities, I got a page full.