(87) There are several modifications of the pedal motion in use, but, before passing on, the arrangements used by Messrs. Platt Brothers and Company may be described. Dealing first with the driving of the cones reference may be made to Fig. [35]. The spindle of the driving cone B is prolonged so as to rest in a footstep and has fixed upon it the double-grooved pulley S. An endless rope or band is passed round the pulley I, which is the driving pulley, and thence passes round the pulley G, carried on a pin, the position of which can be regulated by the screw shown. After going once over the pulley G the band is conveyed round the upper groove of the pulley S, back to G, thence to the carrier pulley shown, again round S, and finally returns to the driving pulley I. A little consideration of the course thus followed will show that there is a pull upon the spindle of the cone B in diametrically opposite directions, and as the pull is in each case equal, the wear of the shaft and footstep is materially reduced. The consequence is that high velocities can be attained with the utmost ease, and without any undue strain upon the ropes or shafts.
(88) Referring now to Fig. [36], which is a front view of the pedal arrangement, it will be noticed that the levers P are each of them placed between two bowls, which are actuated by their own pendants only. Instead of coupling the regulating levers to the last of the series of pendants, a different arrangement is adopted. The hanging lever O is fastened at its upper end on a pin carried by the horn bracket shown, which is fixed to the bowl box. On the other end of the pin is a second lever, shorter than O, and also fixed to the pin. Thus any oscillation of the lever O is followed by a similar movement of the second lever. The lever O is long enough to enter the bowl box, and any lateral movement of the bowls causes a similar movement in the lever. This is repeated by the shorter lever, which is coupled to a connecting rod Q. The latter is made in two parts, connected by a nut, with a right and left handed thread, so as to permit of any adjustment necessary, which is also aided by the slots shown as existing in the various levers in the series. The rod Q is jointed to an L lever R, on the horizontal limb of which the balance weight T is fastened by means of a pin passing through the slot. To the extremity of this limb of the lever R a chain F is coupled, which, passing over a grooved pulley placed above the cone box, is attached to each of the strap levers O P (Fig. [35]). These levers are hinged in the manner shown, and carry strap forks acting upon the strap C. The relative positions of the strap and levers, at a point midway of the length of the cones, are shown by the dotted lines in Fig. [35]. On the spindle of the cone A is the worm L, by which the feed rollers are driven, the three roller arrangement being in this case used, one of them revolving above the nose of the pedal lever.
Fig. 36.J.N.
(89) The action of this mechanism is easily explained. As the pedals are depressed or elevated the bowls are moved laterally, as previously described. The last of the series being in contact with the lever O causes it to oscillate, and, in consequence, the shorter lever jointed to the rod Q is moved. This motion is communicated to the chain F, which exerts a pull upon the strap guides, and raises or allows them to fall as described. One cardinal feature in this arrangement is the power of adjustment which is given at every point, the balance weight T being easily set to give the exact amount of pressure of the lever O upon the last bowl, while at the same time permitting it to oscillate without an excessive power being required. This makes the motion very sensitive, which is assisted by the size of the cones, and by placing the pedals on knife-edged supports instead of a shaft. Usually the cones are made about 4 inches diameter at the large end and 21⁄2 inches at the smaller. In the machine, as made by Messrs. Platt, the cones are 8 and 5 inches diameter respectively at each end, and, as their velocity is high, a slight pull upon the strap vertically is sufficient to move it up or down the cones.
(90) A special arrangement, made by Messrs. Dobson and Barlow, is shown in Figs. [37] and [38] in elevation and plan. Here the pedals W W1 are all of the same shape, and the last of the series W is not coupled to a connecting rod, as shown in Fig. [22]. Instead of this, three bowls, R R T, are placed upon a pin which passes through the forked end of the small frame Z. The rollers R R roll in the groove in the box, and are provided with broad flanges which keep them in position laterally. The roller T is in contact with one edge of the last pendant W, and when the latter is pushed to one side it presses upon the roller and causes it and the cradle Z to move in the same direction. A pin in the other end of the cradle passes through the end of a lever Y, which fits between the fork in Z and passes through a hole in the cross-piece of the bowl-box. The thrust upon the rod Y is therefore given in the centre of the pendants, and these are not liable to be twisted. The rod Y is jointed to the L lever shown, which forms part of the series connecting the pedals and strap guide levers. As shown in the detached sectional view, Messrs. Dobson and Barlow employ between each pair of pendants three anti-friction bowls, U V U, which work loosely upon the pin X. The latter is made in the centre with a boss, eccentric to its main portion, and in this way the central bowl V is caused to engage with the pendant W, while the other two U engage only with the pendant W1. The pin X cannot revolve by reason of being fitted into a square hole in one of the bowls sliding in the groove in the box, so that the relative positions of U and V are always maintained.
(91) In Figs. [39] and [40] a front and side elevation of the pedal regulator as made by Messrs. Asa Lees and Co. Limited, is illustrated. The pedals E are hinged at one end, and rest upon vertical rods J, the lower ends of which press on the extremities of the balanced plates B. Each of these is suspended on a larger plate C, of similar construction, which in turn rests on the extremity of a plate D. The latter is suspended by its centre from a lever, F, which is fulcrumed on a knife edge at H. The lever F is coupled in the manner shown to the strap guide lever I, which is moved by means of the horizontal bar shown, which slides upon guide runners. The cones A A1, are placed horizontally, the advantage claimed for this position being that the strap has a much easier motion along the cones than is the case when the latter are vertical. It will be observed that the whole of the balanced plates are in equilibrium, and are suspended on the end of the lever F. Thus a slight movement of one of the smaller plates, B, is multiplied before it acts upon the lever F, and the regulation of the strap is thus rendered more sensitive.
(92) In Fig. [41] a side elevation of the driving gear used by Messrs. Asa Lees and Co. is shown. In this case the whole of the essential movements are driven by means of one endless rope. This plan obviates the difficulties which arise if a beater strap breaks and the feed continues, or if the delivery ceases from the same cause and under the same circumstances. In this case the lap attachment and cages are driven from the pulley D, the beater and the cones also by the same rope. The direction of the rope’s movement is indicated by the arrows, and a tightening screw is provided to keep the band in tension. On the shaft of the beater is a friction clutch, one-half of which is formed into a grooved pulley. By disconnecting the clutch, the beater can be stopped independently of the rest of the machine.
