- Software name: appdown
- Software type: Microsoft Framwork
- size: 842MB
Machines and tools operating by percussive action, although they comprise a numerous class, and are applied in nearly all mechanical operations, have never received that amount of attention in text-books which the importance of the machines and their extensive use calls for. Such machines have not even been set off as a class and treated of separately, although the distinction is quite clear between machines with percussive action, and those with what may be termed direct action, both in the manner of operating and in the general plans of construction. There is, of course, no lack of formul? for determining the measure of force, and computing the dynamic effect of percussive machines acting against a measured or assumed resistance, and so on; but this is not what is meant. There are certain conditions in the operation of machines, such as the strains which fall upon supporting frames, the effect produced upon malleable material when struck or pressed, and more especially of conditions which may render percussive or positive acting machines applicable to certain purposes; but little explanation has been given which is of value to practical men.
Now the major jumped up and shouted at his subordinate that he had to treat a Netherlander as he ought to be treated.
The action of steam-hammers may also be divided into what is termed elastic blows, and dead blows.
III.The man who called himself Mr. Everdail nodded.
"Are they at a great distance from here?"
In considering pneumatic machinery there are the following points to which attention is directed:The reader may notice how everything pertaining to patterns and moulding resolves itself into a matter of judgment on the part of workmen, and how difficult it would be to apply general rules.