143 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[May, 



BRODERIP'S TROUGH OR TRUNK ENGINE. 



Fig. 1. — Pec I ion. 



TTig. 2.— Section f Casing and Centre^ 



^n 



!n consequence of the late discussion at the meeting of the Great 

 Western Steam Ship Company at Bristol, relative to the intended 

 introduction of "Humphrys' Patent Trunk Steam Engine," for the new 

 iron steam ship now building at Bristol. We felt desirous of obtaining 

 a drawing and some particulars relative to it : upon making enquiries 

 among our scisnlitic friends, we were much surprised to find that a 

 similar engine had been patented by another party nearly seven years 

 antecedent to the patent of Mr. Humphrys ; and was invented by the 

 late Mr. Charles Broderip of Spring Gardens, a gentleman who was 



well known to the scientific world as a clever engineer and scientific 

 man. Upwards of eighteen years ago he equipped a steam vessel 

 called the "Tartar," with which he made a voyage into the Bay of 

 Biscay and back, and by this spirited proceeding was the first person 

 to demonstrate the practicability of sending steam vessels across that 

 tempestuous bav, which, till then, had never been attempted. 



He afterwards invented the application of a casing or trunk attached 

 to the piston, by the use of which, he was enabled to connect the piston 

 rod with the crank direct, as shewn in the accompanying drawing; he, 

 however, died shortly afterwards, and his executor Col. D'Arcy took 

 out letters patent for the invention, dated Nov. •29th, 1828, and a sketch 

 and description of it appeared in a scientific work called the " Journal 

 of Arts" shortly afterwards. 



Some years afterwards, viz., on the 28th March, 1835, Mr. Francis 

 Humphrys again patented, identically the same arrangement of the 

 steam engine, and subsequently proceeded to make a pair of engines on 

 this principle, that were fitted to a steam vessel called the "Dartford" 

 which ran for a short time, but which it is stated, have since failed in 

 the cylinders by the angular friction of the pistons. We shall now 

 proceed to give a description of the engine as specified by both parties, 

 and then leave it to our readers to judge how far Mr. Humphrys is en- 

 titled to his patent, or can be considered as the original inventor, for 

 if there be any merit in the invention, it is only right that the saddle 

 should be placed on the right horse. 



The following description we extract from the specification of the 

 patent granted to Col. D'Arcy: — The specification describes other 

 improvements besides the one inquestion; oneofthem was {ora.sliding 

 stuffing box, " the piston rod connected at one end to the piston, and at 

 the other end to the crank of the engine without the intervention of 

 any cross head, side rods, guide frame or parallel motion to keep the 

 piston in a perpendicular position whilst it is ascending and descending 

 in the cylinder, the improved method of connecting the piston of any 

 cylinder used in a steam engine to its rod is by means of any convenient 

 joint, or by a ball and socket which will allow the piston rod to oscillate 

 or yield to the motion of its crank without altering the vertical or 

 horizontal position of the piston, whilst acting either in a cylinder 

 placed vertically or horizontally as circumstances may require ; and by 

 the introduction of the sliding stufling box, I am enabled to apply the 

 oscillating piston." The specification then proceeds to describe this 

 invention by a reference to the drawings accompanying the specification. 

 A A the cylinder, B B the piston, C C the centre of the joint of piston 

 into which the joint of the piston rod D D is fitted and united ; DD 

 shows the rod forming its greatest angle by the motion of the crank G; 

 E E the sliding stuffing box working in grooves, rabefs or dovetails, 

 made perfectly air and steam tight, and placed securely on the top of 

 the cylinder cover F F. Instead of the sliding stuffing box, the 

 patentee in some cases substitutes " the trough or socktt K K" (showed 

 in the annexed engravings) "firmly connected to the piston, and which 

 trough or socket must be made hollow and of sufficient capacity to 

 allow the piston rod DD to oscillate freely in its width, thickness, 

 and area, so that in its transverse, through the fixed stuffing box E E, 

 and by the gland H, the trough or socket K K may be rendered as 

 securely air and steam tight in its connection with the cylinder A A, 

 as if it was a cylindrical piston rod." 



We shall now give some extracts from the specification of the 

 patent granted to Mr. Francis Humphrys : we did r-ot consider it 

 necessary to give a drawing, as it is so identically like the above. 



The letters in italics within parenthesis, we have introduced, they 

 refer to the above engraving; the other letters are as they appear in 

 Mr. Humphry's specification. " A Ais the cyUnder, B B the working 

 piston, C (G) the crank, D D {K K) a steam tight casing or trunk of a 

 rectangular form rounded at each end, which is permanently attached 

 to th^ piston in such a manner that the axis of the one shall correspond 

 exactly with the axis of the other, and which casing works up and 

 down with the piston, K'E.{F F) is the lid or cover of the cylinder A A, 

 G G {E E) the stuffing box which is made to fit the outside of the easing 

 or trunk D D (A' K) instead of as usual fitting the piston rod." In the 

 concluding part of the specification, Mr. Humphrys states " that what I 

 claim as my invention is the addition, to the pistons of steam engines, 

 of a steam tight casing or trunk permanently affixed thereto, and 

 working up and down therewith, and the employment of a connecting 

 rod passing from the working piston to the crank through such steam 

 tight casing or trunk, both in the same manner herein belore specified ; 

 by means of which contrivance, the reciprocating motion of the pistons 

 is resolved into a rotary motion without the intervention of the beams, 

 cross heads and other auxiliary appendages in common use." 



