Journal . gh thecentre of the grid by hand. Theelement is located in a horizontalposition, a small steel cradleholds the anode which is clampeddown by a hinged upper half,the unit being located against ashoulder. (Fig. 9.) The long wireholding the upper end of thefilament is now formed roundthe base of this apparatus,being pressed by a lever againsta forming surface so that itfinally comes into its correctposition, the end being concentricwith the other two elements. Inthe position in which the unitnow lies the short hookedend of one wire and thelong hooked end of the otherwire are now lying o
Journal . gh thecentre of the grid by hand. Theelement is located in a horizontalposition, a small steel cradleholds the anode which is clampeddown by a hinged upper half,the unit being located against ashoulder. (Fig. 9.) The long wireholding the upper end of thefilament is now formed roundthe base of this apparatus,being pressed by a lever againsta forming surface so that itfinally comes into its correctposition, the end being concentricwith the other two elements. Inthe position in which the unitnow lies the short hookedend of one wire and thelong hooked end of the otherwire are now lying on the centres of two small anvils, and abovethem are two punches located with their centres the exactdistance apart to give the necessary active length to the filament is threaded through the centre of the grid andfirst the short hook is riveted to one end of the filament ; thelatter is then held across the long hook with no tension andthe other junction made. A few small blows with the hammer. Fig. 9. Punches for Fixing the Filament. Elements in the Background. SOME MODERN ENGINEERING PRACTICE IN AMERICA. 47 on the end of a punch is sufficient to drive the hard tungsteninto the softer nickel and makes a positively secure grid forming machine (Fig. 10), consists of three rotatingspindles, parallel, driven at the same speed, one carryingthe hardened steel roller having two grooves upon it givingthe distance of the pitch of the grid ; one spindle carryingone roller with a single groove, which rollers press thewire on to the rotating mandrel giving the inside diameterto the grid ; these spindles are geared together and motor-driven and produce spirals 2 ft. long. A spiral is cutup in sections by placing the requisite number of turnsin the teeth of a comb fitted to a steel block with a stop
Size: 1263px × 1978px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade186, bookpublisherlondon, bookyear1861
