Larger plate.
103. Organ bellows. The lower “feeders” pump alternately into the double-tier upper “reservoir,” which has the upper set of ribs inverted, as shown, to equalise the pressure throughout its rise. The reservoir is loaded with weights to the required pressure.
104. Smiths’ bellows, either circular or hinged at one side.
The valves used for bellows are plain flap valves faced with leather similar to No. 1619.
105. Bell, or gasometer blower, for light pressures and large volumes.
106. Regulator, or reservoir, for blowing engines to steady the blast. The weighted piston serves the same purpose as an air vessel to the ordinary pump.
107. Disc blower, with elastic diaphragm piston.
108. One-crank three-throw blower, for organs, &c., to give a continuous blast. The three feeders deliver into the central triangular box.
Section 8.—BEDPLATES, FOUNDATIONS, AND FRAMING OF MACHINES.
The skeleton framing of a machine for any purpose should be rigid, as light as is consistent with strength and stability (in some cases weight is necessary to minimise vibration), and the ribs, or members of the frame, should be so disposed as to afford the requisite support for all bearings, centres, &c., without redundance; and lastly, symmetry, and a certain degree of elegance and proportion, are desirable. The illustrations are necessarily typical only, and suggestive.
109. Girder section bedplate for horizontal distributed bearing, as in a horizontal engine. It may be used double, and the two parts connected by cross pieces and bolts, as No. 112.
110. Open box bedplate.
111. Closed box bedplate.
112. Double box bedplate with cross tie pieces.
Square or rectangular bedplates are usually of similar sections, stiffened with ribs underneath, and generally cast in one piece.
113. Side frame and distance rod construction, suitable for light machines.
114. Side frames and cross bars on a base plate. This forms a more rigid construction than No. 113.
115. Table and legs.
116. Rectangular openwork box framing. Useful for machines with several cross shafts.
117. Hollow standard for hammers, vertical engines, and any machine raised above the floor.
118. Soleplate and standard for pedestal bracket, &c. Admits of being detached without disturbing the foundation.
119. Wall box for shaft bearings, &c.
120. Arched crosshead for double bearing, bevil gear, &c.
121. Wrought-iron sideplate and distance rod construction.
122. Wall bracket, with wall flange, or tongue, to take the vertical strain.
123. Wrought-iron rectangular bedplate.
Larger plate.
124. Base plate for column, &c., with concrete foundation. The bolts are usually T headed (see No. 1404), in open recesses, so as to be easily removed without disturbing the base plate.
125. Dovetail and key fixing for brackets, bearings, or any separate detail of framing.
126. Foundation for box bedplates.
127. Vertical columnar, or distance rod construction, used for marine engines, vertical engines, presses, &c.
128. Plinth, column, entablature, and cross bracing, used for beam engines and machinery of a straggling kind with many detached parts.
129. Flat bar side framing, strong, light, and cheap, but not very rigid.
130. Wrought-iron L and flat bar rectangular frame, suitable where great rigidity is not needed, but where cast-iron is not safe or desirable.
Wrought-iron is becoming much more largely employed for the framing of general machinery than heretofore, and it is customary in many cases to supplement a cast iron base or frame with wrought iron or steel bars.
Section 9.—CAM, TAPPET, AND WIPER GEAR.
For producing, from plain circular, or reciprocating motion, variable speed or motion, also intermittent and every kind of irregular motion. Cams are either open or covered. Nos. 131, 132, and 133 are open cams; Nos. 137 and 138, covered cams.
131, 132, & 133. Three forms of the “heart” cam, for giving a regular or intermittent vertical motion to a lever end.
134. Crown cam for vertical shaft.
135 & 136. Jumping cams.
137. Covered heart cam.
138. Covered crown cam.
139. Wiper and lever motion.
140. Twisted bar with sliding bush, which travels from end to end of the bar, and being prevented from turning, causes the bar to turn on its axis to the amount of its twist.
141. Crank pin and slotted lever; gives a variable speed with quick return.
Larger plate.
142. Spiral radius bar for opening valve. The valve is lifted off its seat by the radial motion of the lever against the inclined radius bar.
143. Crank pin and slotted lever motion, with slot arranged for irregular or intermittent motion.
144. Eccentric and slotted arm. The pin at the top of the arm has both a vertical and horizontal motion, causing it to trace an ellipse, the pin upon which the slot runs being fixed.
145. Wiper and lever motion, with rubbing plate; used for Cornish valves, &c.
146. Stamp mill.
147. Scroll cam.
148. Crank and lever, intermittent or continuous motion.
149. Piston, or valve rod and lever motion.
150. Similar movement, but with anti-friction roller on end of lever.
151. Rod and lever reciprocating motion, with anti-friction roller.
152. Similar movement, with a socket forged in the rod and the end of lever rounded to allow for angular motion.
153. Diagonal disc cam, or “swash plate.”
154. Motion for belt shifting with dead travel at half stroke. This allows the lever to move a certain distance on each side of the centre without moving the belt shifting bar.
155 & 156. Sectors