Abstract: A mold for curing a green tire which is made of an elastomeric material capable of flowing prior to curing. The mold includes a surface defining a cavity in the mold for receiving the green tire. A passage communicates the cavity with the exterior of the mold. A vent plug is located in the passage. The vent plug has an opening extending therethrough communicating the cavity with the passage. Elastomeric material may flow into the opening to form a projection extending from the tire as the green tire is pressed against the surface defining the cavity during a molding operation. The vent plug has a portion extending into the cavity a predetermined distance from the surface to form a recess in the tire adjacent the projection. The recess provides a space that the projection may deflect into to prevent shearing off of the projection during removal of the tire from the mold.

Abstract: A system for curing a green tire made from elastomeric material includes a tire mold with a surface defining a cavity for shaping the tire. A plurality of vent passages communicate the cavity with the exterior of the tire mold. An inflatable bladder presses the tire against the surface defining the cavity for a predetermined time in response to fluid pressurization. A fluid pressure source pressurizes the bladder. A conduit communicates the fluid pressure source with the bladder. A restrictor member is located in the conduit for restricting the rate of increase of fluid pressure in the bladder to a predetermined rate of increase during the first one-third of the predetermined time. During the first one-third of the predetermined cure time, portions of the tire adjacent the plurality of vent passages cure and restrict the flow of other uncured portions of elastomeric material into the vent passages.

Abstract: The heat-sink capacity of a well-insulated dome curing press lends itself to saving external steam (flowed over the exterior of a mold in the press) when curing an article. Despite shutting off the external steam at about the half-way point in the normal heating cycle, or sooner, the temperature swing at a point 2 inches within the mold is less than 10.degree. F. This small swings allows the point of least cure (PLC) to receive the required number of cure equivalents long after the external steam supply is shut off, that is, while the press is "coasting". In the mean while, the internal heating and cooling cycle of the press may also be shortened for maximum energy savings, or left unchanged. Though the external steam is shut off before the PLC has received the required or specified number of cure equivalents at the PLC, the press-open to press-close cycle remains the same, and the quality of the cure is not measurably affected.

Abstract: The heat-sink capacity of a thick-walled article being cured with a hot liquid supplying heat to one side of the wall, allows the point of least cure (PLC) to receive a higher rate of cure equivalents even after the hot liquid is replaced with a cold liquid. In the mean while, the other side of the wall continues to be heated. Because such a change-over is effected before the PLC has received the minimum number of cure equivalents required to effect a cure at the PLC (a "pre-cure change-over"), a valving arrangement is provided which allows the change-over to be effected without permitting a pressure drop in the bladder sufficient to permit the tire to "blow" because it is as yet uncured when the change-over is effected. Such a pre-cure change-over cannot be made when steam is replaced with water at ambient temperature.

Abstract: The heat-sink capacity of a thick-walled article being cured with a hot liquid supplying heat to one side of the wall, allows the point of least cure (PLC) to receive a higher rate of cure equivalents even after the hot liquid is replaced with a cold liquid. In the mean while, on the other side of the wall continues to be heated. Because such a change-over is effected before the PLC has received the minimum number of cure equivalents required to effect a cure at the PLC (a "pre-cure change-over"), a valving arrangement is provided which allows the changeover to be effected without permitting a pressure drop in the bladder sufficient to permit the tire to "blow" because it is as yet uncured when the change-over is effected. Such a pre-cure change-over cannot be made when steam is replaced with water at ambient temperature.

Abstract: A curing press for tires is operated with a minimum curing time which will provide the near-optimum number of cure equivalents at the point of least cure without locating it. An average temperature for a particular period during the year is "set" in a programmable controller ("PC") based on minimum and maximum temperature measurements made in the curing room during the day and night over a preselected period of time. The actual ambient temperature is measured at the press, which temperature is essentially that of the green tire just before it is loaded in the prss. The PC controls operation of the press, and is used to provide a near-optimum but variable curing period, depending upon the difference between the "set" temperature and the actual (green tire) temperature, and whether it is greater than, or less than the "set" temperature, to provide a near-perfect cure without tracking the point of least cure.

Abstract: Disclosed is a tire mold for curing pneumatic tires wherein the mold includes a mold back, a tread ring and an insulator plate located between the mold back and the tread ring. The insulator plate is made of material that has a lower thermal conductivity than the thermal conductivity of the material in the mold back or tread ring. The addition of the insulator plate between the mold back and the tread ring induces reduction in heat transfer between the mold back and the tread ring allowing the maintenance of higher heat transfer for areas of the tire not shielded by the insulator plate and achieving the lower heat transfer in the area of the tire shielded by the insulator plate.

Abstract: A simple economical multistage vulcanization process is disclosed for producing premium anomaly-free tires wherein the inner liner or curing bladder is supplied with dead end water and steam sequentially in several stages at high pressures which assure thorough diffusion of entrapped air. The internal steam pressure is 250 to 300 psig in stage I to effect rapid heat transfer, the internal water pressure in stage II is from 300 to 450 psig, and the internal steam pressure is 250 psig or higher in the first part of stage III. The overall cycle time for curing radial passenger car tires in "Bag-O-Matic" presses is reduced one minute or more by using internal steam pressures from 250 to 300 psig in stage I and III and reducing the steam pressure near the end of stage III to boil off the residual water.

Abstract: A simple inexpensive modification of existing tire molds used in old steam dome vulcanizing presses provides remarkable versatility and permits curing of truck and farm tractor tires at higher temperatures with higher internal water pressures to reduce curing times 5 to 10% or more while improving tire quality. A thin, flat heat exchanger with outstanding heat transfer characteristics is readily provided on each mold half by welding a flat outer disc and spacers to the mold to form an annular steam chamber of narrow cross section in direct communication with the outer mold face and the vent passages.

Abstract: An apparatus and process are provided for delivering the precise optimum number of cure equivalents to the exact point of least cure for each tire, though the location of the point varies from one tire to another tire of different geometry, and may vary in tires of the same geometry if there is a change in normal operating conditions. A cure is effected with the aid of a small computer means utilizing only two boundary temperature conditions and the ambient temperature, irrespective of where the boundary conditions are sensed.

Abstract: A tire curing membrane has a pattern of interconnected ribs integrally molded on its inside surface. The ribs collectively define a pattern of closely fitted, approximately equilateral hexagons with no non-hexagonal interstices.