Farrow's military encyclopedia : a dictionary of military knowledge . tion upward, and with a slight pres-sure of the hiind. the weight may be lowered as slow-as required, or stopped at any point. Sometimes itliappeus that another stroke of the lever woidd raisethe weight too high ; then raise the lever a little, andpush itdowu slowly, by which the stroke will bemissed. Should the valve stick to its seat, and pre-vent the jack working, by striking the lever a fewsliarp blows up anil down, the valve will be ^. 1 shows the style used when the jack standsiipoii the groimd or light boar
Farrow's military encyclopedia : a dictionary of military knowledge . tion upward, and with a slight pres-sure of the hiind. the weight may be lowered as slow-as required, or stopped at any point. Sometimes itliappeus that another stroke of the lever woidd raisethe weight too high ; then raise the lever a little, andpush itdowu slowly, by which the stroke will bemissed. Should the valve stick to its seat, and pre-vent the jack working, by striking the lever a fewsliarp blows up anil down, the valve will be ^. 1 shows the style used when the jack standsiipoii the groimd or light board, and can be placedunder the work, or where steadiness is 2 .shows the style used when there is not suf-ficient room to get the head of the jack under thework, and is the pattern used for moving heavyguns, boilers, machinery, etc. Fig. 3 shows a formof lifting-jack used for dry docks, pressing flangeson wagon wheel hubs, etc. The piston is entirelyenclosed, thus preventing all grit or foreign materialgetting into the pump and cutting it or preventing. I rigring, pile-drawing, etc. This jack appears likea plain cylinder with rings at each end. bv which toattach the body to be moved. Thev are three ormore inches in diameter, and one and a half or more I feet long, according to the power required, or thedistance the weight is to be moved. It has a force-jMimp on the outside, worked by a lever, whichforces the fluid contained in the cvlinder to the op-posite side of a piston, to the rod of which one of j the rings at the end is attached. Bv this operationthe jack is forced together, drawimr with it the I body to be moved. It will work vertically, hori-zontally, or at any angle. To use the jack, till itthrough the screw in the side of the cylinder withwhiskey and a few drops of oil. To p>ill or lift anv- j thing, make it fast to the jack by chains or ropesthrough the rings at each end, havinn; first extendedit as far as it will go. This is done by frivins: thethumb
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Keywords: ., bookcentury1800, bookdecade188, booksubjectmilitaryartandscience
