THE COLLIERY GUARDIAN AND JOURNAL OF THE COAL AND IRON TRADES. Vol. CX. FRIDAY, NOVEMBER 26, 1915. No. 2865. The “ Diamond ” By T. CAMPBELL We recently were given an opportunity of going over the works of the Diamond Coal Cutter Company Limited, of Wakefield, and inspecting the various types of coal cutters and conveyors which are now manufactured by this well-known firm, -who have earned a world-wide reputation for this class of machinery. Since the war commenced, however, they have been more or less disorganised as regards the manufacture of mining plant, through being engaged on munition work. The Diamond Coal Cutter Company were one of the first firms of engineers to place their plant and services at the disposal of the Government, and for many months past they have been busy on Government orders, a circumstance which naturally disorganises to some extent their ordinary business as coal cutter manufac- turers; and they have been obliged to put down a quan- tity of extra machinery and plant, so as to put their customers to as little inconvenience as possible. The Diamond Coal Cutter Company, as one of the oldest firms of coal cutter manufacturers in the country, are too well known to require any special introduction. Originally, we believe, they started with one only type of machine, the “ disc,” but they are now making the “ bar ” and “ chain ” type of machines as standard patterns, in addition to many special types to suit abnormal conditions. Every part of the standard machine is made to gauge, and is interchangeable, and spare parts are always in stock, ready for despatch at a moment’s notice. Improvements in design, however, are always taking place, as thought and experience dictate, to increase the efficiency of the machines, for, naturally, there can be no standing still in this direction. The latest pattern of the electrically-driven “ disc ” machine is shown in figs. 1 and 2, whilst figs. 3 and 4 are from photographs of the same machine from different points of view. The machine can be fitted with either an alternating- or direct- current motor. If the latter is used, it is of the four-pole type, fitted with two commu- tating poles. In either case, the motor spindle is pro- vided with ball and roller bearings, and will develop 40 b.h.p. It is contained in a strong cast steel easing between the controller and gear box, and is so constructed as to be readily taken apart for overhaul or repairs. The gear box forms the middle section of the machine, and, as will be seen, is of massive design, and all gearing and bearings are of ample size. The gears are all machine-cut and thoroughly case-hardened, and all thrusts are taken on ball-bearing thrust rings. Further, the bearings are all lubricated by an automatic valve- less oil pump. The controller is contained in a strong box at the end of the machine, is of substantial design, and may be operated from either end of the machine. The end of the trailing cable is fitted to the male end of a special substantially constructed adapter, which fits the female part connected to the machine, and is arranged to swing over in either direction according to the travel of the machine. Thus the cable has always a straight lead or pull, so that all bends in the cable are avoided. The male end of the adapter is locked in position, and there is also a special interlocking device which makes it impossible to withdraw the adapter and cable unless the switch is in the “ off ” position. Attached to the left-hand end of the gear box is the propelling or “ feed ” gear, as it is more commonly termed. This also is very strongly constructed, the rope drum being driven through spur gearing, which, in turn, is operated through adjustable ratchet gear. The feed can be controlled or regulated between the maximum and minimum limits, whilst the machine is running. The machine will cut in either direction, and pro- vision is made for curving the haulage rope over the top of the machine by providing the rollers as shown. The over-all dimensions of the machine are :—Height, Coal Cutting and Conveying Machines. FUTERS, M.LM.E. 101 in.; length, 9 ft. 6 in.; width, 3 ft. 3 in.; and the depth of undercut can be made anything desired. The Standard compressed-air motor-driven machine of the disc type is shown in figs. 5, 6, and.7- As will Fig. Bah ©TO Fig 2. Figs. 1 and 2.—Standard Electrically-driven Coal-cutter. r- '* ■ ■MMIW MT 25^*^ ■A* Fig. 3. .6® Fig. 4. Figs. 3 and 4.—Standard Electrically-driven Coal-cutter. be seen, this type is of very strong construction, all the parts being accurately fitted together. The engine consists of a pair of double-acting cylinders, set opposite each other and working on one crank shaft, the power being transmitted through the machine-cut gearing, as shown, to the centre or crown wheel pinion shaft. As in the case of the electric driven machine, an automatic valveless pump is fitted for lubrication. The over-all dimensions are :—Height, 18 in.; width, 2 ft. 6 in.; and length, 9ft. 6in. It can be fitted with a disc to give a depth of undercut from 3 ft. 6 in. to 5 ft. 6 in. at floor level. Figs. 8, 9, and 10 show the “ Diamond ” enclosed 1. type four-cylinder compressed air-driven chain type long- wall coal cutter. This consists of four single-acting short-stroke trunk pistons, with the connecting rods on one crank shaft. This crank shaft drives a pair of bevel wheels, and through these, by means of spur gearing, the