(under subclass 428) Process including fastening a first part to another part having a cavity by applying force to at least one of the parts to cause a portion of the first part to be inserted in the cavity, the relative dimensions of the inserted part and cavity being such that the parts are distorted within their elastic limits to secure them together.
(1) Note. A force fit is considered to exist if the overall dimensions of the hole or inserted part are not permanently changed. Thus, the formation of lands and grooves in the hole, effected by forcing a splined part thereinto, is found in this subclass since the parts are held together in the direction of assembly by the elasticity of the parts.
SEE OR SEARCH THIS CLASS, SUBCLASS:
432, for a process of assembling including punching, piercing, or reaming a part by a surface of a second part combined with or including force fitting the parts together, and see (1) Note, above.
433, for a process of assembling by stringing.
446+, for a process of assembling in which the parts are distorted within their elastic limit before assembly into the joined position. A force fit differs from prestressing a part, i.e., the art in those subclasses, in time of application of stress, in that the stress in a force fit is initiated at the time of joinder whereas in prestressing of those subclasses the stress is applied prior to the time of joinder. For example, forcing a rod into a hole of smaller size so that the parts are held by the frictional engagement of the rod and sides of the hole is a process of force fitting for subclasses 525+. However, if the same rod is stretched within its elastic limit to thin it and inserted in the same hole while stretched, and the stretching force is then released to permit the rod to expand radially outwardly to frictionally grip the sides of the hole, that process is considered classifiable in those prestressing subclasses,
e.g., subclasses 446+.
505+, for a process in which parts are secured together by distorting at least one of the parts beyond its elastic limits.
