REF ID:A39823 

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A means ot providing an irregular wheel movement 

in Cipher Machinesusing cipher wheels. 

The basic principle of this invention utilizes the cipher wheels of 

the cipher machine to provide an irregular selection of the particular 

wheel which is to be moved. A method of effecting this selection is to 

provide, in addition to the present ring of 26 contacts on each face of the 

wheel, a second rbJg ot 26 contacts, which contacts are independent ot the 

first mentioned set of contacts, but are connected to each other in an 

irregular manner, analogous to the manner in which the first mentioned set 

of contacts are connected. Also the end plates will bear a double ring of 

contacts which coincide exactly with the two rings of contacts on the face 

of each cipher wheel. These two rings of contacts on each end plate are 

connected as indicated in Figs. l and 2 or the attached drawing. 

The action of the machine is as follows: When a key is depressed, two 

contacts are closed, namely, (1) the key contact which allows a current to 

pass through one of the above-mentioned rings of contacts to operate f1D 

indicating device giv.ing the encipherment ot the letter corresponding to 

said key an~ (2) a universal contact which permits current to enter at a 

single contact of the other of the aforementioned rings of contacts on one 

of the end plates, pass through one of the contacts of the corresponding 

~s of oontacts of all the cipher wheels, and pass eut at one o£ the 

contacts on the corresponding ring or contacts or the other end plate, 8llll 

thence to a seleeting magnet which permits the eipher wheel corresponding\ 

@'pproved for Release by NSA on 09-30-2013 pursuantto E.O. 1352e v \ 
• • 

thereto to move forward. 

Figure 1 is a schematic diagram of the invention. 1, 2, 3, 4, and 5 

are the hereinbef'ore described cipher wheelsJ 19 and 20 are the end plates, 

6, 7, 8, 9, 10 are the wheel selector magnets which 8.u.ovr a mechanism to 

step one of the wheels forward at each depression of a key; 11 and lJ are 

the rings of contacts through which the current passes to the wheel 

selector magnetaJ 12 and 14 are the rings of contacts through which the 

11kq to lamp• current passesJ 15 is the key contact; 16 is the above-mentioned 

universal bar contact; 17 is the source or powerJ 18 the reversing aitch; 

21 is the indicating device; and 22 is the connection to the mdversal contact 

which mq be connected to &JO' ,contact of the rings of contacts 11 on end 

plate 19. 

Fig. 2 shows one1 manner 1n whicll the riDg of contacts on end plate 20, 

, through which the current passes to the selector magnets, are connected to 

the wheel se1ector magnets. 

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