28 IMPROVED GUN LOCK. 



VII. 



Defcription of an improved Gun-Lock, by iVfr. George Dodd,* 



T 

 Defcnption of A HE figures io Plate I. reprefent Mr. Dodd's improved 



*ufrkKk^\\r ga"-lock with its parts in their feyeral fituations and pofttions. 

 leference to the The fl}aded drawing, Fis^. i . reprefents the exterior parts of 

 drawings. the lock ; and Fig. 2. reprefents its interior. Fig. 6. exhibits, 



in perfpeclive, the tumbler, the fear and the fear fpring in 

 the pofition of whole coclc. The outline plans 3, 4 and 5 

 fliew the feveral pofitions of the parts, at full cock, haU cock, 

 and immediately after the difcharge. The tumbler A termi- 

 nates on the lower fide in a tail, as ufual ; upon which the main 

 fpring a6ls: bul, on the upper or oppofite fide, it is formed 

 fp as to have two notches or bents, one very deep for the half 

 cock, and the other fliallower for the whole cock, as is feen in 

 the figures. The circle a, Fig. 3, fuppofed to be defcribed 

 by the extremity of the bearing face of the tumbler at whole 

 cock, is larger than that through which the extremity of the 

 bearing face of half cock paflTes, fee Fig. 5. and the center of 

 the fear B is placed in the outer of thefe two circles, having 

 the under fide of its nofe fafiiioned in the arc of the circle b Z>, 

 defcribed by the motion of its extremity. The bearing furfaces 

 of the bents or i:oiches of half and of whole cock are made 

 to fit this face; or, in other words, they form parts of the 

 fame circle, when refpedively at whole or half cock, D is 

 the trigger, fo formed and placed that, at whole cock it trips 

 or draws out the fear, with great facility and quicknefs, by the 

 &^ion of an inner Hope or face lying in the diredion of a ra- 

 dius of the circle it defcribes; (fee Fig, 4.) But when at half 

 cock. Fig. 3, its a6lion, by means of an outer flope or furface 

 (which lies intermediate between radii drawn from the centers 

 of the fear and of the trigger to the inner point of their con- 

 ta6l) is fo far from difcharging the motion, that it tends to keep 

 the fear more ftrongly in its place. T'hefe adtions and proper- 

 ties are fufficiently evident from the figures, 

 "Enumeration of The advantages of this lock are, 1. It is fully as fimple in its 

 ihe gocd quail- conftru6lion, or rather morefo, than the common lock, and is 

 t.M u t us oc . ji^gj-gfofg j^o lefs cheap and eafy to be cleaned by a common 



* From the Tranfa^ions of the Society of Arts for 1804. 



foldier 



