Abstract: A safety cap (10) which is screwed onto an external thread (24) of standard tire valve (22) consists of a cylindrical body (11), a cup-shaped barrel (26) which is threaded onto an external thread (17) of the cylindrical body (11), and a control valve which consists of a plunger (42), a valve seat (50), a spring (46), and a guide pin (40). This valve is located in a space (B) formed between the inner face of a barrel bottom (30) and the facing end of the cylindrical body (11). The control valve is constantly adjusted, during the assembling of the safety cap at a factory, to a maximum pressure allowable for a predetermined tire. In case the pressure in the tire exceeds the maximum allowable value, e.g., because of an increased load or high temperature air will push the plunger (42) away from the tire valve and will be released into the atmosphere through a check valve (62). Thus the pressure in the tire will be automatically adjusted to a level not exceeding the maximum allowable one.

Abstract: A safety core (10) for a tire valve comprises a head portion (12) screwed into the valve's housing (28) so that it is sealed against the inner wall of the housing by compressing a seal ring (36) located in an annular groove (34) formed in a tapered portion (32) of the head part. Inserted into the head part is a cylindrical body (14) which contains a ball-type check valve (20). A ball (84) of the valve is constantly pressed to a seat (80) installed on the rear end of an adjustment pipe (16), the latter being screwed into the rear end of the body (14). The rear end protrudes through the head portion (12) and has a stop (58) on its end. A spring (62), located between the stop (58) and the outer end face of the head portion (12), constantly urges the front end of the head portion (12) to a valve seat formed on a shoulder (68) of a large-diameter portion (66) of the cylindrical body.

Abstract: A universal filter changer for theatrical lighting units comprises a casing, a mechanism for attachment of the filter changer to the lighting unit, a set of filter holders with lighting filters, and a unit for switching the filter holders with filters between two extreme positions. This unit of a set of identical switching mechanisms the number of which corresponds to the number of the filter holders. Each mechanism is formed by a movable part which can rotate with respect to a stationary part by means of an electromagnet which controls a mechanism which in turn prepares fixing pawls for fixing the movable part, and hence the respective filter holder, with a filter in one of extreme positions of its rotation. With the use of such mechanism, the filters can be selected in any random sequence as well as in any combination. The mechanism can be controlled manually via a remote control panel or interfaced to a microprocessor-based controller.

Abstract: Encoded magnetic strip cards are fed into apparatus which reads encoded data on the card. The card is fed into and out of the apparatus through a passageway defined by a guide which also serves as a mount for mechanical and electronic components. The guide is precisely constructed so that the thickness and width of the passageway are slightly greater than the corresponding dimensions of the card and the card does not jam in the passageway. In one form of the invention the guide is formed of two generally T-shaped, overlapping, interfitting members. In a second form of the invention the guide is formed of two opposed T-shaped side members and two plates relieved at their edges to receive the legs of the side members.