694 HENRY A. ROWLAND 



(26), to which the bell-crank (42) is pivoted, causes the pawl to rise to a 

 height corresponding to the number' of teeth to be engaged on the 

 graduated ratchet-head. The other lever (40) has the function of 

 engaging and disengaging the pawl. The cycle of operations that 

 occurs in one revolution of the main shaft is as follows: The pawl-lever 

 (26) is raised by the cam (47), and in so doing gauges the degree of 

 revolution to be imparted to the graduated ratchet-head and feed- 

 screw. The other lever (40), which is pivoted on the pawl-lever (26), 

 is raised further, and thereby permits cam (46) and the bell-crank (42) 

 to carry the pawl (41) forward into engagement with the graduated 

 ratchet-head. The weight (45) attached to the bell-crank arm insures 

 a positive engagement of the pawl. The depth to which the pawl enters 

 between the teeth of the graduated ratchet-head is governed by the 

 adjusting screw (43) and a stop on pa,wl-lever (26). The pawl being 

 engaged, both levers (26 and 40) now descend, causing the graduated 

 ratchet-head and feed-screw to turn to an extent governed by the 

 number of teeth engaged. Lever (40) now descends to a position coin- 

 cident with that of the lever (26), and in so doing causes the stop on 

 lever (40) to press against the adjusting screw (44) on the bell-crank, 

 and thereby withdraws the pawl from the teeth of the graduated ratchet- 

 head. 



III. Diamond and ruling head. See Figs. 1 and 5. 



The diamond (1) is firmly secured by means of solder in a holder 

 (2), which may be adjusted to different inclinations. The frame 

 carrying the diamond, holder and dash-pot has an axle, centering in 

 bearing screws (3) and contained in an adjustable support (4). This 

 support may be raised or lowered to meet the requirements of plates of 

 different thickness. Normally, the end of the frame carrying the 

 diamond and holder, owing to its predominance of weight, would cause 

 the diamond to be in contact with the plate continuously. In order to 

 raise it on the return stroke of the engine, a weighted lift rod (57) is 

 caused to press on the end of the frame near the dash-pot. The height 

 to which the diamond is thus lifted off the plate is governed by nuts, 

 which may be adjusted on the stem of the lift-rod and which on their 

 descent come to rest on the plate 56 A. 



The raising of the weighted lift-rod is primarily caused by cam (55) 

 on the main shaft; the intermediate mechanism consists of the lever 

 (54), vertical oscillating rod (53), reciprocating rod (35), rocking stem 

 (34), and lifting lever (56). The action of the dashers and dash-pot 



