PORTABLE PROSPECTING DRILL.
The Aqueous Works and Diamond Rock-boring Company, Limited, of London, show at the Inventions Exhibition, London, a light portable rock-boring machine for prospecting for minerals, water, etc. It is capable of sinking holes from 2 in. to 5 in. in diameter, and to a depth of 400 ft. The screwed boring spindle, which is in front of the machine, is actuated by miter gearing driven by a six horse power engine; the speed of driving is 400 revolutions a minute. The pump shown on the left-hand side of the engraving is used to deliver a constant stream of water through the boring bar, the connection being made by a flexible hose. Suitable winding gear for raising or lowering the lining tubes, boring rods, etc., is also mounted on the same frame. The drill is automatic in its action, and the speed can be regulated by friction gearing. The front part of the carriage is arranged so that it can be swung clear of the drill to raise and lower the bore rods, etc.
AUTOMATIC SAFETY GEAR.
Among the safety appliances which are to be found in the Mining Section of the Inventions Exhibition is a model of an ingenious contrivance for the prevention of overwinding, the joint patent of Mr. W.T. Lewis, Aberdare, lead mineral agent to the Marquis of Bute, and W.H. Massey, electric light engineer to the Queen. Both these gentlemen, having been members of jury, were not allowed to compete for an award. The invention, says Engineering, seems to possess considerable merit, and it should prove of practical utility in collieries where enginemen are usually kept winding for many hours at a stretch, and where the slightest mistake on the part of the driver may lead to an accident.
Safety hooks are often fitted to winding ropes, and although the damage to life and property is greatly reduced by the use of them, they do not protect a descending cage from injury in a case of overwinding; besides which, they are almost useless when a wild run takes place, an accident which, strange to say, has already occurred many times after engines and boilers have been laid off for repairs. Stop valves are left open, the reversing lever is not fixed in mid-gear, steam is got up in the boilers at a time when no one is in the engine house, and the engines run away.
LEWIS & MASSEY'S AUTOMATIC SAFETY GEAR.
Various devices have been suggested and tried as a preventive, but their application has either caused as much mischief as a bad accident, or it has depended upon the driver doing something intentionally; whereas in the automatic gear of Messrs. Massey and Lewis, of which an illustration is annexed, there is nothing to cause damage or to interfere in any way with the proper handling of the engines, and it is practically out of the power of the driver to render the gear inoperative. It is here shown in its simplest form as applied to the ordinary reversing and steam handles of a winding engine, the only additions being an arm jointed to the top of the valve spindle, with its connections to the shaft of the reversing lever, and a disk receiving a suitable motion from the main shaft of the engine. On the disk is a projecting piece or stop which is brought into such positions, at or near the end of each journey, that the stop valve cannot be opened, except slightly, when the reversing lever is not set for winding in the proper direction, or when the cages have reached a point beyond which it is undesirable that the engine driver should have the power of turning on full steam. Thus, if one cage is at bank, the driver cannot draw it up into the head gear suddenly; but after it has been lifted slowly off the keeps or fangs, and the reversing lever thrown over, the stop valve can be lifted wide open; and supposing that while the engine is running the driver neglects to shut off steam in proper time, then the projecting piece on the disk in traveling round, slowly or quickly, and by steps according to requirements, will come in contact with the driver, and so prevent an accident by bringing the reversing lever into or beyond mid-gear.
Messrs. Lewis and Massey contemplate the use of governors in combination with various forms of their automatic gear, so as to provide for every imaginable case of winding, and also to avoid accidents when heavy loads are sent down a pit; the special feature in their mechanism being that when two or more things happen with regard to the positions of steam or reversing handles, speed or position of cages in the pit, whatever it may be necessary to do to meet the particular case shall be done automatically.