Abstract: A method of making a press-moldable glass, including melting starting materials, forming a melt, and annealing a formed glass, wherein the melt has a composition such that, (1) when rapidly cooled to room temperature, it becomes glass that has a scattering coefficient of less than 0.005 cm?1 at wavelengths of from 400 to 2,500 nm or comprises crystals with a volumetric ratio of less than 10?6, and (2) when maintained for three hours at a temperature 10° C. higher than the glass transition temperature, maintained for 10 min at a temperature yielding a viscosity of 104.5 to 103.5 dPa·s, and then rapidly cooled to room temperature, (3) the resulting glass has (a) a scattering coefficient of at least one wavelength from 400 to 2,500 nm of greater than 0.01 cm?1 or (b) crystals with a volumetric ratio of greater than 10?5. A temperature for annealing is lower than for glass transition.

Abstract: There is provided a device for manufacturing a molded glass body, including a fall-prevention means for preventing the glass molded body which has stuck on the upper mold from falling down on the lower mold. Thus, the molded glass body does not damage the lower mold, even if the molded glass body which has stuck on the upper mold falls down from the upper mold, during a period from an end of the pressure molding to releasing and withdrawing the molded glass body obtained by the pressure molding from the any one of the upper mold and the lower mold.

Abstract: The forming apparatus has top and bottom die assemblies which form a heated silica glass material by press forming. These top and bottom die assemblies include, respectively, mold dies, which are made of isotropic carbon, and core molds, which are made of vitrified carbon. The heating and pressing time of a silica glass element, which requires a high forming temperature, is shortened by pinching the silica glass material between top and bottom core molds by controlling a torque so as to produce a close contact condition which permits heat transfer from the top and bottom core molds to the silica glass material between the top and bottom core molds.

Abstract: An object of the present invention is to enable to use a common transfer machine for transferring performs to and for transferring products from a press-forming system for glass having a plurality of press units. The press-forming system for glass has a plurality of press units. A linear moving stage is arranged in the proximity of the press units. A transfer robot is mounted on the linear moving stage. A pallet changer is arranged in the proximity of an end of the linear moving stage. A tray presently in use is mounted on a first mount and a new tray on standby is mounted on a second mount on the pallet changer. The inner space of the tray is partitioned into sections so as to correspond to press units in number. In each section, a plurality of pockets is arranged for storing preforms or products one by one.

Abstract: The forming apparatus has top and bottom die assemblies which form a heated silica glass material by press forming. These top and bottom die assemblies include, respectively, mold dies, which are made of isotropic carbon, and core molds, which are made of vitrified carbon. The heating and pressing time of a silica glass element, which requires a high forming temperature, is shortened by pinching the silica glass material between top and bottom core molds by controlling a torque so as to produce a close contact condition which permits heat transfer from the top and bottom core molds to the silica glass material between the top and bottom core molds.

Abstract: A method for fabricating a mold tool for molding optical elements is taught which comprises heating a mold tool blank made from a vitreous material to a temperature above the glass transition temperature of the vitreous material; generating an axial viscosity gradient in the mold tool blank; pressing a punch into an optical quality mold surface of the mold tool blank, the punch including a pressing surface with a predetermined geometry for forming an optical feature; cooling the mold tool blank to a temperature below the glass transition temperature of the material; and removing the punch from the mold tool blank thereby creating the optical feature in the optical quality mold surface. The axial viscosity gradient is achieved by creating an axial thermal gradient.

Abstract: A method of and apparatus for bending and tempering a sheet of glass heated to a formable state provides an improved rigid mold and pressing member for pressing the heated sheet against the rigid mold which cools and bends the sheet. The pressing member includes a conformable pressing element which permits a manifold to be positioned between the rigid mold and the pressing member to direct a gas to cool the heated sheet of glass during bending. The conformable pressing element is pressurized into a convex shape for initially pressing on a portion of the heated sheet and for rolling the heated sheet onto the rigid mold. The rigid mold and the conformable pressing element may each include a cover to increase the heat transfer from the heated sheet to the bending and tempering apparatus. Furthermore, the covers may have increased thermal conductivity in their peripheral regions for increased cooling of the edge of the sheet of glass.

Abstract: A glass object having protrusions and/or recesses, for example a glass lid (1) with a handle (2), is produced in an IS machine by pressing molten glass from above in a mould with the cover of the mould, in a mould defined by said cover, by a shaping mould (11) and by a mouth mould (13) disposed under the shaping mould. When the glass lid is formed its handle projects downwards and lies in the mouth mould. SUbsequently the glass lid is transferred together with the mouth mould to the finishing mould (12) and is at the same time returned into a position in which the handle projects upwards in the finishing mould in which it is cooled supported by the finishing mould.

Abstract: A system for forming hollow pressed glass articles utilizes a flow of cryogen that is mixed with air to provide a cooling gas that enables newly pressed articles to be removed from their molds after a thin skin of solidified glass has been formed on internal surfaces of the articles to strengthen the newly formed articles and to give them shape stability. Two flows of cryogen are used, one being a gentle, substantially continuous flow of cryogen gas from a low pressure source, the other being a controlled intermittent flow of cryogen vapor in liquid and/or gaseous form from a high pressure source. To assure a proper introduction of cryogen vapor, and to prevent debilitating accumulations of ice within and about the tube that is used to inject high pressure cryogen, the high pressure injector tube is surrounded by a low pressure cryogen flow tube, through which a flow of low pressure cryogen gas is maintained on a substantially continuous basis.

Abstract: In order to form a steam cushion between a glass and a metal mold during operation blowing the glass in the mold, the mold is provided with a large number of small holes mechanically-formed in and distributed over the inner surface of the mold for retaining water therein. Since the metallic inner surface of the mold is directly exposed to the molding cavity of the mold, the mold is not substantially subjected to abrasion and burning during the blowing operation so that the working life of the mold is extended.

Abstract: Glass or glass-ceramic vessels are formed with a pouring lip wherein wall portions of the vessel below the lip are of a thinner construction than the remaining wall portions so as to impede glass flow to the lip area and facilitate uniform glass flow to upper portions of the vessel during the forming process.

Abstract: An improved glass pressing machine which captures exhausting cooling gas to reduce noise in the vicinity of the machine. A glass press for making television face plates includes a cooling station where large quantities of a gas, such as air, are blown on a newly formed article to remove residual heat. Escape of this air creates a noise problem in the area of the machine. The tube which introduces the gas is substantially enclosed by a shroud. The gas, as it completes its cooling function, is conducted from an exhaust pipe in the shroud to a vent stack which delivers the gas to a location remote from the machine. The spent cooling gas is therefore not exhausted at the machine location to create a noise problem.