(under subclass 336) Subject matter including valve springs and means for mounting the spring on the valve.
SEE OR SEARCH CLASS
123, Internal-Combustion Engines,
90.65+, for poppet valve operating mechanism which includes valve springs and the seats and retainers for the springs.
267, Spring Devices,
1, for spring devices of general utility.
411, Expanded, Threaded, Driven, Headed, Tool-Deformed, or Locked-Threaded Fastener, 427+, for nuts; and subclasses 531+ for washers of general utility.
