The Brewster Wind-wheel (fil. 7o, fig. 2) exhibits another form of con struction in which the wind effects the setting of the vanes by means of a bar in a hollow shaft. This bar (E), however, is not toothed, as in the preceding device; but to attain the same object it carries on its outer end cross-bars (F), to whose points and thence to one corner of each vane cords (G) are fastened. While the force of the wind acting on the sails A tends to shift or to press in the bar E in the direction indicated by the arrow, a curved movable bar (II) opposes this action by being pressed against the bar E by the weight J. The adjustment caused by this action and coun teraction of the bar insures the proper inclination of the vane-surfaces, to the force of the prevailing wind. The mechanism of the small wheel effects the setting of the large wheel in the direction of the wind, and the face-gear D, Ii transmits the power to the vertical shaft.
Kirchweger' s shown in vertical cross-section in Figure 7, is constructed entirely of sheet iron, and is provided with a regu lating device similar to the wheel in Figure 2. The illustration repre sents one of the sails in its edgewise position to the wind, and also the hollow shaft enclosing the shiftable bar which acts at the back of the mill against a lever and is provided at its outer end with a five-armed cross. To the left (in the cut) is given a front view of the cast-iron hub, which is connected with the wheel-shaft and serves to fasten the five whips of the vanes, as also the cross in front of it. This form of wind-wheel is success fully employed for water-stations on many Hanoverian railways.
Tfliiting's (fig. 4) is supported by a frame (A) and rests upon a ring (D), which is rotated on rolls in the journals a. The wheel is adjusted by a bar (D), which is shiftable in the hollow shaft c. The bar bears with its inner end (fig. 3 in plan) against a socket (I), held by the cords or chains f, the pulleys F, and the weights G. The vanes are turned on their whips by a rack-mechanism placed on the outer end of the bar. The sails H can be furled or unfurled on the rollers h, h by the pulleys u fastened on them, and the cords in, r, as also by the blocks q, S.• Cubitt's of which Figure i (fil. 71) illustrates the central portions of two sails, has in a hollow shaft a movable bar which serves also as the principal regulating mechanism. In this wheel the vane-cov ering, however, does not consist of wood or of sail-cloth, but of a kind of sheet-iron Venetian blind; so that, instead of a twisting of the entire vane surface on its whip with a change in the force of the wind, a shifting of the separate component parts of the blind is effected. The tendency of the increasing pressure of the wind is to impart to the levers B, A, L, by means of the racks L, the position indicated by the dotted lines, but at the same time the weight G, suspended to a cord or chain (F) and wound around the drum, counteracts this movement by the small cog-wheel on the drum-shaft actuating the rack D on the shiftable bar C, thus effecting an adjustment for every variation of the wind.
Brown's If place of the shiftable bar iu a hollow shaft, Dr. Frank, Johnson, Brown, and I.,empcke have used for their wind wheels the mechanism shown in Figures S and 9 (pl. 70) and Figures 2, 3, 7, and 9 (pl. 71), described as follows: In Brown's wind-wheel (p/. 7 1, fig. 3) the rods G,.11 are connected by loose joints to a linb, which is movable on the wheel-shaft. The rods are also attached to the whipti by socket joints (II), in which the whips can move. By this mechanism the increas ing pressure of the wind tends to slide the hub along the shaft, but in so doing has to overcome the resistance of the weight I' suspended to the lever 0; as also that of a spiral spring placed between the hub and a socket connected with the wheel-shaft. The momentary acceleration of the rota tion of the wheel caused by an increased force of the wind impels the sails // radially outward by the centrifugal action of the heavy bearings L (shown on an enlarged scale in Figure 2), and thus, by means of the helical groove L, turns the vane-surface and effects a change in the angle of incidence. The wheel, as shown in the Figure, is set face to the wind by the large vane I? connected with the frame. The transmitting mechanism is repre sented enlarged in Figure 4.
Dr. Frank's and Johnson's in Figure 6 (p1. 70) the regulation of the angle of incidence is effected, with the assistance of centrifugal force, by the ball-governor, and in Figures 2 and 3 (AL 71) by a weight (L) provided with a spiral groove, the principle applied in the wheels (pl. 70, figs. 8, 9; p1. 71, Jig. 7) constructed by I)r. Frank and Johnson is that of weights, one of which is designated by c in Figure 7 (p1. 70. It is shiftable on the bar c, c, and is held in a certain position by a spiral spring secured to the bar. To the weight are fastened the rods r, laterally connected with three vanes, which can be turned on their whips. In acceleration of the speed of the wheel forces the weights radially out ward as far as the spiral springs will permit, and by the connection of the rods causes the turning and consequent flattening of the vanes. The por tion of tho frame moved by the large vane is rotated on a hollow axis sup ported by the fixed frame and pivoted on the ring S, which is connected with the horizontal portion of the revolving frame by an oblique stay and a vertical rod (II). Through the hollow axis passes the vertical driving shaft, which engages, by means of bevel-gears, with the wheel-shaft, and carries on its lower end the pulley-wheel 1/ for the transmission of the motion and power to the working machines. Besides being secured to the vanes, the centrifugal weights are also connected with levers (pl. 70, Jig. 9), which, by acting upon a brake-wheel, bring the wind-wheel to a stand-still. Figure S, of which Figure 9 is a front view of the wheel, represents a con struction which differs from Figure 7 (pl. 7r) only in having a lighter frame and in being provided with a vane covered with sail-cloth.