This section is from the book "Machines And Tools Employed In The Working Of Sheet Metals", by R. B. Hodgson. Also available from Amazon: Machines and tools employed in the working of sheet metals.
Fig. 156.
The single-acting cutting-out press, fig. 157, is one known by Messrs. Daniel Smith and Co. as the"Gem Series,"the special feature of this press that has caused it to receive such a title being that the body and stand are cast in one piece. The connecting rod swings on a ball base, which allows of its free rotation on the upper or bearing part of the rod. This gives a ready and simple mode of vertical slide adjustment, to suit the variable lengths of the tools, or the extent to which the punch enters the bed, or the degree of pressure that is required to be put upon the work in the case of raising or pressing. The stop motion is of the annular type, having three engaging slots. The engaging key will rotate the press in either direction, and it automatically disengages when the slide reaches the top of its stroke. It will be noticed that in this type of press the flywheel is supplemented with fast and loose pulleys. This saves the band or belt being thrown off the driving pulley or flywheel when tools are being set, or when the press is in any way put to rest. This point is mentioned because it frequently happens that small presses of this kind are driven from the flywheel, which makes it necessary at times to remove the belt altogether from the machine.
Fig. 157.
Fig l58.
The small single-acting press, fig. 158, would generally be useful for small work in any kind of sheet metal, say, for instance, blank cutting, up to 1 1//2 in. diameter of 14 B.W.G. metal, or its equivalent. The adjustment of slide is made by packing plates, a method previously explained (see figs. 41 and 42). A plate in the front of the slide, being readily removable, gives free access to its adjustments. On presses of this type a small hand wheel may be fixed upon the shaft at the back of the flywheel, to enable the shaft to be moved by hand for tool setting purposes. The stop motion is of the double peg type, the peg passing through and being supported by the boss of the flywheel. This is a safe and handy arrangement, there being no tendency for the shaft to rotate when setting tools. The friction lever or handle seen on the side of the slide guide serves to retain, by friction, the slide in any position of its stroke, while the vertical adjustment of the slide is effected to suit the length of the tools which are being set"When this friction lever has not been attached to presses of this single-acting type, the author has known instances where experienced tool-setters have had the ends of their fingers smashed whilst changing the adjusting plates, the trouble being caused through the slide falling down, due to its own weight.
Fig.159.
A compact form of geared single-sided press, which takes up but little space, is seen at fig. 159. It has a vertical adjustment in the slide, being also fitted with a special sliding block stop motion, made to work by treadle. This stop motion automatically disengages when the slide reaches the top of its stroke.
A single-sided press is shown at fig. 160. In this case it has a massive box stand and a back drive, there being a friction clutch at the back, inside the two speed cone pullies. The clutch gives a ready means of stopping the entire press, because with the two speeds the loose pullev cannot be used except by the aid of a countershaft. But if the top driving cone is fitted on the main shaft, the friction clutch, as shown, gives stopping and starting control of the gearing, while the usual stop motion in the slide is variable 'for constant use if required when cutting out. This back drive is very convenient for driving the press from a shaft overhead. The geared incline press, fig. 161, is suitable for piercing or holing large washers, axle plates, or raising ferrules, or bending articles into shape either in the hot or cold state. The press, as illustrated, would cut out a blank 4 in. diameter by 4 in. thick. The stop motion is arranged for hand or foot, and a screw adjustment is fitted to the connecting rod. The main casting is in one piece. The front stay bolts are removable, and the rate of speed in such a press, if piercing axle plates or similar articles, would be about 70 revolutions per minute.
Fig. 160.
Fig. 1(51.
The open-backed press, fig. 162, is designed to be used either as incline or upright pattern, single acting or geared, as required by circumstances. This is a very handy type of press, suitable for users who require to deal with small quantities of work having a wide range-that is, light, medium, and heavy. A belt put on the wheel, seen at the right of the illustration, will work the press as a single-acting one, suitable for light sheet pressings or raisings, such, for instance, as can bottoms and tops, tin boxes, and similar articles; or, by sliding the pinion on the back shaft into gear and putting a belt on to the pullies, seen at the left of the illustration, the press at once becomes a geared one, available for such work as electric-light fittings, bending and forming, cutting out, lock plates, spoons, since the use of the gearing gives a slower speed and greater power to the slide, thereby enabling much thicker metal to be cut The slower speed is often a great convenience, as it admits of a continuous feed, without the constant use of the stop motion, as is often the case on some kinds of work. The open back is available for the work to fall through when the press is being used as an inclined press. Fig. 162 shows the press placed in position, ready to be used as an upright one. By loosing the bolts which pass through the semi-circular base of the press, the body can be tilted to a suitable angle, thereby converting the press into an inclined one. The press stands on heavy cast-iron legs.
 
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