(under subclass 153) Devices in which there are means in the casing or tubing in which the piston operates cooperating with the piston to stop its motion.
(1) Note. A stop means which comprises merely the top or bottom of the casing or tubing (e.g., the inwardly sloping wall of a set shoe) is not included. See subclasses 153+ for such devices.
(2) Note. A means in the tubing or casing which stops the piston only until fluid pressure is increased is also not included. See subclasses 153+ for such devices.
(3) Note. The stop means may be for preventing an upward motion of the piston after it is driven down the well.
(4) Note. The stop means must be more than merely the
bottom piston of a pair of pistons.
SEE OR SEARCH THIS CLASS, SUBCLASS: 154, for pistons, fluid driven into the well, engaging a valve part which acts as a stop or engages some other stop means.
155, for pistons which allow fluid to flow past them after they contact a stop.
170+, for stops associated with brushing, scraping or cutting type cleaners.
193+, for dropped balls or plugs of the type which do not make a close fit with the surrounding conduit as they move downwardly combined with stops.
