1S42.J 



THE CIVIL ENGINEER AxND ARCHITECTS JOURNAL. 



73 



Q. 1322. What do you mean by self-acting breaks ? — A. When- 

 ever the power is taken off the engine by the engine-driver, it imme- 

 diately ceases to proceed so fast; all the carriages immediately run 

 towards the engine, with the impetus put into them before tlie engine 

 was retarded. Every carriage, as it approaches the next carriage, 

 sball apply the breaks itself. Every carriage is brought into the state 

 of a sledge; the rolling motion of the wheels ceases; ami supposing 

 that an engine was running on with twelve or fourteen coaches, and 

 that every coach had a breaksman (that is, twelve coaches and twelve 

 breaksmen), and the whole of them upon the look-out to see if any- 

 thing went wrong in the engine, to apply the breaks immediately, I 

 conceive that the self-acting princij-le is fifty tinus bitter. 



DESCRirnox of drawings. 



Fig. 1 shows a mode of applying breaks to the engine : a is a strong 

 iron carriage for the breaks laying flat against the side framings, bear- 

 ing on and attached to the centre cf the springs, and supported also 

 by sliding freely through a plate or staple bolted to tlie su\e frame, to 

 allow for the play of the springs; 6 is a vertical shaft, on the bottom 

 of which is a worm, taking into a worm-wheel, keyed on a horizontal 

 shaft, which passes across beneath the foot-plate ; on the same shaft 

 are keyed two pinions c, working into two racked sectors or levers d; 

 on bringing the levers to the position shown, the break-bands are 

 brought down on the tops of the wheels on both sides of the engine ; 

 on fiving the handle a contrary motion, the break-bands are lifted into 

 the position shown by the dotted lines. Any elastic substance, or 

 wood segments in an iron box, may be bolted to the underside of the 

 break-bands, if thought desirable. 



Attached to the tire-box of the engine is a bell f, on which, by an 

 arrangement of spring-levers, a sharp blow, or several blows, can be 

 instantaneously struck by the guards from any carriage in the train, a 

 simple and effectual mode of communication with the chain g running 

 along the tops of all the carriages. 



Fig. 2 is a side elevation of a railway carriage frame. At one end 

 is a self-acting break, proposed to be applied to all the wheels; a is 

 a connecting-rod attached to the buffers ; 6 is a bell-crank, the axis of 

 which is attached to the side frame of the carriage ; c is a strong belt 

 of leather, plaited hemp and wire rope, or any suitable material, to 

 the underside of which, if necessary, plates of metal may be rivetted; 

 rf is a curved spring, to the end of which, and to the bell-crank b, the 

 belt c is fastened ; upon the buffer being driven in, the bell-crank 6 is 

 moved in the direction of the dotted line, and the belt c is brought 

 down on the periphery of the wheel, with a force proportionate to the 

 strength of the spring d, which, on the buffer resuming its position, 

 takes the pressure of the belt c off the wheels. 



The ether end of Fig. 2 shows a Manual break : e is a vertical 

 shaft, on the bottom of which is a worm, working into a worm-wheel 

 on a horizontal shaft /, and giving motion to a pair of bevil-wheels g, 

 one of which is attached to a short vertical shaft, carrying a piniou h, 

 which takes into two racks i »', kept in gear by friction-rollers at the 

 back ; the ends of the racks are prolonged, and attached to the centres 

 of two bars passing across the carriage, and carrying at each end the 

 bows ti' fitted with elastic bands, on boxes fitted with segments of 

 wood or otherwise. 



Fig. 3 is an elevation of a railway carriage frame, showing another 

 form of atlf-nclivg break ; a a are strong iron rods attached to the 

 centres of two cross-bars b b, which are lixed at each end to the back 

 of the buffers; the other ends of the rods a a are forked, and pass 

 over a spring c c, the ends of the sprinpp impinge against bars d d, 

 passing across the carriage, on the ends of which are fixed boxes fitted 

 with segments of wooil, or w ith bows, &c. similar to k k in Fig. 2 ; / 

 is a curved stay in the plane of action to the centres of the wheels, on 

 which are formed guides for the ends of the bars dd; the springs c c, 

 and the bars d d' ', are shown in section ; the rods a a are capable of 

 adjustment in the length, so as to bring the breaks into action when 

 the buffers shall have been driven in to any point desired; the action 

 of the breaks on all the wheels is simultaneous, and the force equal to 

 the strength of the springs c c' '. 



It will be perceived, that one advantage in these breaks is the 

 absence of concussion on their being applied, as they are governed by 

 the bulfers. More or less force is applied, as more or less occasion 

 exists for the same. Should the strength of the buffer springs be at 

 any time insufficient to admit of the backing of a train, there is a readjr 

 mode of preventing the action of the breaks upon the wheels. 



SLUICE GATES. 



Description of the Bear Trap Sluice Gates of the Lehigh Descending 

 Xacigalion. j5y Ell wood Morris, Civil Engineer. 



(From the American Franklin Journal.) 



The public are indebted to the inventive genius of Josiah White, 

 Esq., President of the Lehigh Coal and Navigation Company, for the 

 admirable hydrostatic contrivance which has received the singular 

 name of Bear Trap. 



These sluice gates were devised in the year 1^18 by the " Lehigk 

 Kiivigation Company," for the purpose of improving the Lehigh river 

 by means of wing-dams, iS;c., so as to form a descending navigation 

 suitable for the transportation of coal from the Anthracite mines, near 

 JIauch Chunk, to the city of Philadeljdiia. 



This work was commenced upon the lOlh of August, ISIS, and did 

 not originally contemplate the use of sluice gates as a primary expe- 

 dient; the residents upon the margin of the Lehigh river having 

 pointed out "a certain mark in a rock at the Lausanne landing," as 

 the low-water level of the stream, the Company were induced to 

 believe that there would always be a sufficiency of wafer for their 

 purposes, if it were "confined by wing-dams in its passage over the 

 ripples, or shoals, from pool to pool," and under this impression the 

 work was begun; but in the autumn of I'slS " the water in the river 

 fell by an unparalleled drought, as was believed, fully twelve inches 

 below the mark which has been mentioned as shown by the inhabi- 

 tants to be the lowest point to which the river ever sunk. Here was 

 a ditficulty totally unanticipated, and one trhich required a rtry essen- 

 tial alteration in the plan. Nature did not furnish enough water by 

 the regular flow of the river, to keep the channels at the proper depth, 

 owing to the very great fall in the river and the consequent rapidity 

 of its motion. It became necessary to accumulate water by artificial 

 means, and to let it off at stated periods, and let the boats pass down 

 with the long wave thus formed, which tilled up the channels. This 

 was effected by constructing dams in the neighbourhood of Mauch 

 Chunk, in which were placed sluice gates of a peculiar construction, 

 invented for the purpose by Josiah White, one of the managers, by 

 means of which the water could be retained in the pool above, until 

 required for use. When the dam became full, and the water had run 

 over it long enough for the river below the dam to acquire tlie depth 

 of the ordinary flow of the river, the sluice g;ites were let down, and 

 the boats, which were lying in the pools above, passed down with the 

 artificial flood." 



It was to meet the exigency created by the discovery above-men- 

 tioned, that Mr. White contrived the beautiful sluice gate, which we 

 are about to describe, and upon the successful operation of which the 

 whole enterprise very much depended. 



At that day the scene of the Company's operations was almost a 

 perfect wilderness, and the carpenters having been set at work to 

 frame a sluice gate for trial, it became an object of great curiosity to 

 the settlers ; who being far more riiniliarwith the implements u«ed in 

 the chase and capture of the beasts of the forest, than with the hy- 

 draulic works of a flash navigation, either in jest, or from sunic fancied 

 resemblance of the sluice gate to a Bear Trap, quickly gave to it this 

 cognomen, which it ever since has borne. 



M 



