Aspects of the Physical Reality

Abstract

This chapter contains a miscellany of matters that are nevertheless related. First I present a few ideas about the inevitable question of simple interference among the teeth of wheels and ways for avoiding it. Associated with this simple interference, which always pertains until, as an ordinary matter of course, we avoid it by truncation, there is however a more serious phenomenon. This I have called, for the want of a better name, either the excessive pointedness of teeth, or the mutual decapitation of flanks, which, when it occurs in design, does so as a kind of accident. It occurs, by definition, when the otherwise full, unity-plus of one or other of the contacts ratio, is reduced to below unity. Such an event, of course, unless especially looked for for some particular reason, is catastrophic. Next there is a kind of envelope, ill defined as yet, within which we are safe against this dangerous phenomenon, but beyond which we are not. I try to come to terms with this. Finally I describe an apparatus [54], free of these faults and faithfully based upon the results of WkEx#1, which confirms that the velocity ratio k of a properly designed, spatial involute gear set is insensitive to all small errors of assembly; we can see with the help of this apparatus that if the errors are not small, but large, the troubles outlined in this chapter will obtrude.