Figure 2. Additional original handle styles. Documentation has not been

found for these additional styles, but they are believed to be original. 

 

EUREKA IMPROVED SPIRAL SCREWDRIVER

EAIA member Ed Mahoney has provided information on a model which appears to be based mainly on Olson’s 1884 patent (Figure 3, No. 306,096), the most common model. But, Mahoney’s model also had one feature taken from O. Z. Greene’s 1890 patent (Figure 4, No. 422,520), of which no examples have been found to date.

Although Mahoney’s model (Figure 5) follows very closely the 1884 patent, it does incorporate a chuck/bit holder for holding a removable, double-ended bit, the same feature claimed in O.Z. Greene’s 1890 patent.  It is marked: EUREKA IMPROVED / PAT. MAR.- 4 1890 / DECATUR COFFIN CO. / DECATUR, IL. This model was obviously intended as an upgrade to the common Decatur Coffin Company screwdriver, which was sometimes marketed as the  “The Eureka Screwdriver.”

Another feature of Mahoney’s model, which does not appear in the Greene patent or in any of the four Olson patents, is a pair of lugs on the rear of the chuck/bit holder.  These lugs engage in notches at the front of the barrel for positive engagement to produce counter-clockwise motion to remove screws without forcing the handle to move longitudinally. This function is accomplished on the common Decatur Coffin models by notches at the rear end of the internal “nut” or clutch, which engage with a lateral pin at the rear of the brass tube to produce a positive lock. (The bit pictured in Figure 5 is a reproduction. The handle on this example is not shown since it is not original.)

Figure 4. Patent illustration for the O. Z. Greene patent of 4 March 1890.  O. Z. Greene was a founder

and presidentof the Decatur Coffin Co. Note chuck and removable, interchangeable bit.

Except for the chuck/bit-holder and the positive engagement lugs, this model follows more closely the common version, based on the 1884 patent (#306,096) of C. H. Olson, than it does the 1890 patent (#422,520) of O. Z. Greene.  While in the patent the clutch is enclosed within the bit-holder/chuck, in this example the clutch is enclosed in the tube at the rear of the shaft as in the common version.  It is marked: EUREKA IMPROVED / PAT. MAR. - 4 1890 / DECATUR COFFIN CO. / DECATUR, IL.

The lugs on the rear of the chuck/bit holder engage in notches at the front of the barrel for positive engagement in order to produce counter-clockwise motion and to allow removal of screws without the handle being forced into longitudinal motion. This function is accomplished on the common Decatur Coffin models by notches at the rear end of the internal "nut" or clutch which engage with a lateral pin at the rear of the brass tube to produce a positive lock.  The handle on this example is not shown since it is not original. The bit pictured is a reproduction. (Figure 5.)

 This model was apparently intended as an upgrade to the common Decatur Coffin Co. screwdriver which was marketed as the  "The Eureka Screwdriver" as well as "The Decatur Coffin" and "Olson's Patent."  However, due to the extremely limited number of examples of this model which have been seen, the "Improved Eureka" must not have found acceptance with users.