Abstract: An extruding system includes a mixing unit configured to mix a polymeric material with a blowing agent and to form a mixture, and an injection unit coupled to the mixing unit and configured to inject the mixture. The mixing unit includes a mixing cartridge, a first mixing screw and a second mixing screw, the first and second mixing screws are disposed in the mixing cartridge. A method of extruding a mixture includes mixing a polymeric material and a blowing agent in a mixing cartridge of a mixing unit by at least one of a first and second mixing screws to form the mixture; conveying the mixture from the mixing unit to an injection unit; and discharging the mixture from the injection unit into a molding device. The mixture is sequentially in contact with the first mixing screw and the second mixing screw.

Abstract: The present invention provides a transfer molding mold for a vulcanized rubber boot, comprising: a combined tube mold, having an inner cavity corresponding to a tube of the rubber boot a last mold with partition elements, having a main body substantially corresponding to the tube of the rubber boot in shape, and two or more partition elements disposed on the main body, wherein the last mold is suitable for installation into the inner cavity of the tube mold to form a transfer molding cavity between the wall of the inner cavity of the tube mold and the outer surface of the last mold, and the transfer molding cavity is partitioned into two or more parts by the last mold and the tube mold; and a rubber injection guide plate suitable for installation to the top of the tube mold to guide injection of unvulcanized mixed rubber, comprising a plate body, wherein the plate body is provided with: a rubber injection port to be connected with an external injection head to inject the unvulcanized mixed rubber; and an annu

Abstract: Provided are an injection molding machine and an injection molding method. An injection molding machine includes: a plasticizing unit which rotates a screw to plasticize a molding material inside a plastication cylinder, and an injection unit. The injection unit has: a plunger reciprocally moving inside an injection chamber, and an injection driving device reciprocally moving the plunger. By driving the injection driving device to move the plunger backward and forward inside the injection chamber, and driving a rotary driving device to alternately rotate the screw in a normal rotation direction and a reverse rotation direction, the molding material is controlled to reciprocate between the plastication cylinder and the injection chamber.

Abstract: A control device of an injection molding machine, the injection molding machine including: a mold clamping device that advances and retracts a movable mold with respect to a fixed mold; and an injection device that injects and fills a molten material into a cavity formed between both the molds, the control device including: a display unit that displays a setting screen for setting molding conditions of the injection molding machine; and a setting unit that sets the molding conditions based on information displayed on the setting screen.

Abstract: A molding material supply device and a molding material supply method capable of supplying a degassed molding material to a molding apparatus at a desired timing are desired. According to the molding material supply device and method of the disclosure, a first discharge member is driven to discharge a molding material accommodated in a first accommodation member to a second discharge member through a through hole of a die, and a second discharge member configured by the first accommodation member and the die advances to discharge the molding material having been degassed in the second accommodation member to the molding apparatus from a molding material supply port.

Abstract: An injection piston drives a screw. An injection hydraulic cylinder drives the injection piston and is partitioned into first and second chambers. A first oil discharge port is disposed in the injection hydraulic cylinder to be blocked by a piston part when the piston part of the injection piston advances to a pressure-holding switching position, and discharges hydraulic oil from the second chamber. A second oil discharge port is disposed in the injection hydraulic cylinder to be capable of discharging hydraulic oil from the second chamber regardless of the position of the injection piston. The injection piston has first and second members. The joint of the first and second members is disposed at a position separated from an end of the piston part on a side of the second chamber by a predetermined distance.

Abstract: A hot runner process controller configured to monitor the status and operation of a hot runner system to autonomously generate information to improve the quality of injection molding process of a hot runner system having an inlet nozzle, one or more manifolds and one or more nozzles with actuator or without actuator, and one or more heating elements, the hot runner process controller is self-operating, and independent from the injection molding machine, includes: one or more sensors located on, in or at the hot runner system to detect the status and/or the operation of the hot runner system, and a processing unit and a memory. The processing unit is connected to the one or more sensors, wherein the memory stores data and program codes.

Abstract: This invention relates to a method for moulding products from a mass of food stuff, comprising: —moving a mould cavity, which is part of a mould member past a feed channel which fills the mass into the cavity, wherein the feed channel is connected to a feed pump which pumps the mass through the feed channel into the cavities. —determining and/or detecting the position of the mould cavity relative to the feed channel, controlling the desired set pressure of the pump.

Abstract: A low-pressure powder injection molding machine, a kit and a method thereof. The machine has a feedstock container adapted to contain mixed feedstock, a mold and an injection device. The mold has an inlet and a cavity in which the feedstock material can set. The injection device has an injection port for supplying the mixed feedstock from the container to the mold by using pressure. The machine also has a moveable platform adapted to provide movement between the injection port of the injection device and the inlet of the mold in order to directly communicate the feedstock between the injection port and the inlet without using an intermediate conduit and thereby preventing any feedstock from setting or dissociating between the injection port and the inlet.

Abstract: A screw (20) for rotating within a material supply cylinder (22) to plasticize a material is able to reciprocate in the axial direction, between a retracted position away from a communicating passage (41) through which a plasticization chamber (23) leads to an injection chamber (33), and an advanced position at which the screw closes off the communicating passage. The screw position adjustment device includes: a thread (50) immovable with respect to the material supply cylinder, and having a through-hole (51) extending in the axial direction; a position adjustment nut (56) threadably engaged at the outside peripheral face of a thread for determining the retracted position; a fastener (58) for securing the position of the position adjustment nut; and a casing (72) covering the position adjustment nut and the fastener, and having an opening (73) for moving closer to the position adjustment nut and the fastener.

Abstract: An injection unit for an injection molding machine includes a nozzle for dispensing melt to a mold, and a valve housing having a first port in fluid communication with the nozzle. The valve housing has a second port and a third port. A plasticizing barrel is in fluid communication with the second port. A shooting pot is in fluid communication the third port. A valve closure member is mounted in the valve housing. The valve closure member is moveable between a first position in which the first port is in fluid communication with the third port and in fluid isolation of the second port, and a second position in which the second port is in fluid communication with the third port and in fluid isolation of the first port. When in at least one of the first and second positions, fluid communication is provided between the respective ports through a gap provided between an outer surface of the closure member and an inner surface of the valve housing.

Abstract: An injection molding system having a shooting pot assembly is disclosed. In one embodiment, the shooting pot assembly is in fluid communication with a mold and has an actuation direction that is substantially perpendicular to an injection axis of material injected into a mold cavity. In another embodiment, a shooting pot actuation system is a mounted on a side of a hot runner. In certain embodiments, the shooting pot actuation system includes a linear actuator operatively coupled with the shooting pot assembly to actuate the shooting pot assembly.

Abstract: An injection unit for an injection molding machine includes a nozzle for dispensing melt to a mold, and a valve housing having a first port in fluid communication with the nozzle. The valve housing has a second port and a third port. A plasticizing barrel is in fluid communication with the second port. A shooting pot is in fluid communication the third port. A valve closure member is mounted in the valve housing. The valve closure member is moveable between a first position in which the first port is in fluid communication with the third port and in fluid isolation of the second port, and a second position in which the second port is in fluid communication with the third port and in fluid isolation of the first port. When in at least one of the first and second positions, fluid communication is provided between the respective ports through a gap provided between an outer surface of the closure member and an inner surface of the valve housing.

Abstract: A platen-supported system (105) for use with a molding-system platen structure (107), the platen-supported system (105) comprising: a frame assembly (103) connectable with the molding-system platen structure (107); and at least one plasticating device (201) supported by the frame assembly (103). A molding system (100) having a mold frame assembly (203) configured for supporting a molding assembly (200), and the at least one plasticating device (201) located within the mold assembly (200).

Abstract: Plasticizing system for plasticizing solidified-resin particle, plasticizing system, comprising: housing assembly providing: (i) melt channel configured to receive solidified-resin particle, and (ii) opposite-facing surfaces spaced apart from each other, and defining, at least in part, convergene channel configured to receive the solidified-resin particle. Opposite-facing surfaces and the convergence channel form part of melt channel. Plunger assembly is movable, at least in part, relative to opposite-facing surfaces. Plunger assembly configured to move, at least in part, solidified-resin particle relative to opposite-facing surfaces along, at least in part, convergence channel. In response to relative movement between solidified-resin particle and opposite-facing surfaces, solidified-resin particle receives, in use, plasticization-inducing effect from opposite-facing surfaces.

Abstract: A tool for a resin transfer molding method comprises a cavity, a resin trap and a transition region, wherein the cavity is designed such that a component can be accommodated in it. Furthermore, the resin trap is integrated in the tool, and the transition region is designed such that with it a connection between the cavity and the resin trap can be established.

Abstract: An injection apparatus includes a pressure accumulating portion, which is connected to an injection cylinder, and a speed reduction mechanism, which reduces the speed of the injection cylinder arranged in the injection apparatus. The speed reduction mechanism includes an actuating member, which moves integrally with a rod of an injection cylinder rod, and a restriction member, which is arranged in a flow passage for draining or supplying hydraulic oil from or to the injection cylinder, and variably narrows the flow passage in conjunction with movement of the actuating member.

Abstract: A hollow body molding device having molten resin injected into a main cavity, fluid is pressure-injected through a pressure port after the injection of molten resin, a floating core moves to the outlet side, the molten resin is extruded from the outlet simultaneously with the movement of the floating core, and a hollow molded body is molded, the hollow body molding device having a floating core storage portion connected to the main cavity and stores the floating core moved by the pressurized fluid, an auxiliary cavity stores molten resin discharged from the main cavity and the floating core storage portion, communication passages and which communicate the floating core storage portion and the auxiliary cavity with each other; and an opening and closing means that opens and closes the communication passages by sliding movement. In the hollow body molding device, each inlet cross-sectional area B of the communication passages is specified.

Abstract: A mold-tool system for use with a molding-system platen structure, the mold-tool system a frame assembly being connectable with the molding-system platen structure (107); and a set of shooting-pot assemblies being supported by the frame assembly, wherein control of each shooting-pot assembly of the set of shooting-pot assemblies is independent.

Abstract: A device for producing plastic moldings has an extruder and a molding tool arranged downstream of an extruder discharge opening. A screw is rotatably guided in the extruder and is axially displaceable to transfer liquid polymers, prepolymers or monomers present in the extruder into the molding tool. A nonreturn valve adjacent to a free end of the screw has a locking ring in contact with the inner circumferential wall of the extruder that includes a seal, which is applied to at least part of its outer circumference and which seals the locking ring against the circumferential wall of the extruder. The sealing material of the seal is selected from the group of the polymers, copolymers and polymer blends with a hardness lower than that of the circumferential wall of the extruder. A nonreturn valve and method of processing liquid prepolymers or monomers into plastic moldings is provided.

Abstract: A resin transfer molding (RTM) molding device is designed to mold a fiber-reinforced plastic (FRP) molded body by injecting a resin composition into a mold and by impregnating the molded body therewith. The resin composition is a chain curing polymer (CCP). A CCP accommodating layer is disposed adjacent to an outer side of the molded body. The layer contains the CCP. The layer is provided with a Vf limit value, the value defined by the curing characteristics of the CCP and the characteristics of dissipation of heat from the CCP to the exterior. An element for separating the molded body is disposed between the body and the layer.

Abstract: There is provided an injection unit.

Abstract: A resin transfer molding (RTM) molding device is designed to mold a fiber-reinforced plastic (FRP) molded body by injecting a resin composition into a mold and by impregnating the molded body therewith. The resin composition is a chain curing polymer (CCP). A CCP accommodating layer is disposed adjacent to an outer side of the molded body. The layer contains the CCP. The layer is provided with a Vf limit value, the value defined by the curing characteristics of the CCP and the characteristics of dissipation of heat from the CCP to the exterior. An element for separating the molded body is disposed between the body and the layer.

Abstract: A top-gate molding system for encapsulating semiconductor devices includes a plurality of mold cavities formed between a middle plate and a bottom plate, and a runner system formed between an upper plate and the middle plate. The runner system includes a runner with a plurality of reservoirs along its length, with a gate extending from each of the reservoirs to one of the cavities. A particle trap is positioned on the bottom of the runner between a sprue and a first one of the reservoirs, to capture contaminating particles in a flow of molding compound before the particles enter any of the reservoirs. The particle trap can be, for example, a notch or a channel extending transversely across the bottom of the runner, or a dummy reservoir upstream of the first of the plurality of reservoirs.

Abstract: An embodiment molding apparatus includes a main cavity and a buffer cavity connected with the main cavity.

Abstract: A molded article transfer device (150, 250) is described herein that is associated, in use, with an injection mold (100, 200). The molded article transfer device (150, 250) includes a transfer structure (151, 251) that defines, amongst other things, a first aperture (154A) that is structured to receive a first molded article (102A) from a first mold stack (106A, 206A) of the injection mold (100). The transfer structure (151, 251) also defines a first branch channel (156A) and a first trunk channel (158A) through which the first molded article (102A) is passable. The first branch channel (156A) connects the first aperture (154A) with the first trunk channel (158A) for passing, in use, the first molded article (102A) thereto, whereafter it passes through the first trunk channel (158A) towards an exit (164A) thereof.

Abstract: An injection molding system (20) is provided including an extruder unit (22) having an injection actuator (38) for injecting a melt into a mold assembly (40); and a clamping unit (24), the clamping unit (24) configured to retain the mold assembly (40) during injection. A power pack (46) is provided, including a fixed-target accumulator assembly (62) operable to discharge hydraulic fluid at a fixed hydraulic pressure to the clamping unit (24) and a first pump being connected with the clamping unit (24), the first pump operable for charging the fixed-target accumulator assembly (62) to the fixed hydraulic pressure. The power pack (46) also includes a variable-target accumulator assembly (66) operable to discharge hydraulic fluid at a variable hydraulic pressure to the injection actuator (38) during the molding cycle; and a second pump connected to the variable-target accumulator assembly (66), the second pump operable for charging the variable-target accumulator assembly (66) to the variable hydraulic pressure.

Abstract: As an injection screw 2 applies pressure, a holding pressure plunger 22 is moved backward under the pressure of a resin to flow the resin into a holding pressure path 9, and the resin in a resin path 6 is pressurized (primary holding pressure process). A shutoff plunger 12 is closed, and the resin in the resin path 6 and the holding pressure path 9 is pressurized by the holding pressure plunger 22 (secondary holding pressure process). Further, the shutoff plunger 12 is opened, and the holding pressure plunger 22 is moved forward until its tip projects into the resin path 6 to discharge all the resin in the holding pressure path 9 to the resin path 6, whereby the resin beside the injection screw 2 as compared with the shutoff plunger 12 is held with respect to the holding pressure path 9.

Abstract: A sprue bushing includes a head, and a main body. The main body is connected to an end of the head. The main body defines at least one lateral channel. The at least one lateral channel extends through a sidewall of the main body. The sprue bushing defines a sprue and at least two longitudinal channels. The sprue extends through the head and the main body along a center axis of the sprue bushing. The at least two longitudinal channels extend through the head into the main body. One of the at least one lateral channel communicates with two of the at least two longitudinal channels.

Abstract: An injection molding machine includes a hydraulic driving system providing hydraulic power; a molding system configured for molding a workpiece; and an injection system configured for injecting a molten material to the molding system with the hydraulic power. The injection system includes a cylinder and a piston movably received in the cylinder. The cylinder is surrounded by one of an alternating current-charged coil of wire and a closed-loop coil of wire, and the piston is surrounded by the other, whereby the piston receives acceleration for movement in the cylinder.

Abstract: A plastic material injection molding system includes a feeding nozzle, a forming mold having a cave therein, and a material-passing mold having a runner therein. The runner communicates both the feeding nozzle and the cave, and has two curved parts therein for slowing down the plastic material injected from the feeding nozzle in order.

Abstract: There is provided an injection unit.

Abstract: To prevent defective molding, a base member is set between split molds of a metal mold, a molding rubber material is injected into an endless shape cavity defined between the base member and the split mold, an injection amount thereof is made such that the molding rubber material fills the cavity and thereafter flows from an air vent hole open to a confluence position in the cavity into a surplus material reservoir provided downstream but does not fill the surplus material reservoir, pressure drop due to flow resistance is caused to the molding rubber material flowing into the surplus material reservoir, and thereby pressure in the cavity is maintained to be not lower than pressure required to mold a gasket and lower than pressure causing leakage from the cavity.

Abstract: An injection molding tool having a first section moveable with respect to a second section. In a first position, the first section contacts the second section along a parting line and forms a cavity. An expandable cavity part is moveably mounted with respect to the second section. In a closed condition, the expandable cavity part is in a retracted or molding position. The expandable cavity part can be moved away from the molding position or the closed condition to a release position or an expanded condition with allows access to molded part or other article. A core pin is either moveably mounted with respect to the expandable cavity part or is in a fixed position with respect to the expandable cavity part.

Abstract: The invention relates to a plasticizing and injection unit (1) of an injection moulding machine To inject especially smallest amounts of plastic melt in an injection moulding tool for injection moulding of small and smallest parts in a process optimized way the unit comprises a screw cylinder (2) in which a plasticizing screw is arranged rotatable and axially movable and an injection element (4) comprising a piston-cylinder system (5, 6), wherein a metered amount of plastic melt, which is deposited in a section (7) of a cylinder (6), is expelled via an injection nozzle (8) into an injection moulding tool by an axial movement of a piston (5) in the cylinder (6), wherein a flow path (9) is arranged between the end of the screw cylinder (2) and the section (7) of the cylinder (6) and wherein the flow path (9) is free from valve elements. Furthermore, the invention relates to a method for injection moulding of a part.

Abstract: A nozzle valve gate for injecting hot plastics into an injection mold includes a body having a passage for flow of the plastics to an outlet and forming an actuator chamber. A nozzle part is connected to the body and extends longitudinally to a nozzle tip having an injection aperture. The nozzle part has a flow passageway connected to the plastics outlet for conducting the plastics melt to the injection aperture and a machined bore forming a guide passageway. A valve pin is movable in the guide passageway between open and closed positions. A piston is connected to the pin and is slidable in the actuator chamber. An elastomeric wiper seal extends around the valve pin adjacent the machined bore, is wear resistant, and can withstand high temperatures of at least 200° C. A micro gap is formed between the pin and the machined bore.

Abstract: A method for the manufacture of a molding composition from a raw material melt which is charged with an additive includes the steps: charging a conveyor apparatus with a raw material which includes a liquid or gooey pasty composition or a granulate; converting the raw material into a raw material melt by heat supply to the raw material; charging the raw material melt with an additive; mixing of the raw material melt with the additive to produce a molding composition; and discharging the molding composition from the conveyor apparatus. The charging of the raw material melt with the additive takes place through a metering device which is arranged in a passage section of the conveyor apparatus and/or subsequent to the conveyor apparatus with the raw material melt flowing through and/or around the passage section. The metering device includes at least one metering element which is arranged in a recess of the passage section.

Abstract: Torques and resin pressures applied to a screw are detected during the forward movement of the screw and coefficients of correlation between the detected torques and resin pressures are calculated. When the check ring is open, the flight of the screw receives resin pressure, and the screw torque increases proportionally to the resin pressure due to resin backflow, so the coefficients of correlation between the screw torques and the resin pressures are higher than a reference value. When the check ring closes, the flight of the screw no longer receive resin pressure, so the screw torque decreases and the coefficients of correlation become lower than the reference value. The check ring is determined to be closed when the coefficients of correlation become lower than the reference value.

Abstract: A plastification and injection unit in injection-molding machines for processing of polymer materials, for example rubber, has a plastification screw that is disposed so as to rotate in a screw cylinder, which simultaneously represents the injection piston. The screw cylinder is disposed in an injection cylinder, in an axially displaceable manner. The injection cylinder can be connected with the sprue channel of an injection-molding die by way of a nozzle, and the injection piston has a back-flow barrier. The screw is axially displaceable in the screw cylinder by means of a separate drive. The screw tip projects out of the screw cylinder and has a closure body having a sealing surface for contact with the face surface of the screw cylinder.

Abstract: A molding device including a mold having a stationary portion arranged on a stationary platen of a press, and a movable portion arranged on a movable platen of the press, at least one injection channel for injecting material into the movable portion of the mold, and a feeder device for feeding the mold with plastics material, the feeder device including a stationary installation including a first metering device for metering a first quantity of material. The feeder device includes at least one second metering device arranged on the movable platen, the second metering device being connected to the first metering device in such a manner as to be fed with plastics material by said first metering device, and being connected to the injection channel for injecting material into the movable portion of the mold in such a manner as to be capable of feeding it with plastics material.

Abstract: In an injection molding die, there is defined a cavity for a frame or a cavity for the frame and an auxiliary cavity communicating with the cavity for the frame, and into the cavity for the frame or the auxiliary cavity, there is injected a melted resin from a runner through a gate, and a section of the gate has a width of 1 to 5 mm in the direction of a thickness of a plate glass and a width of 10 mm or more in the direction parallel with a side of the plate glass but smaller than a side length of the plate glass. When this die is practically used, a load that would be applied to a peripheral portion of the plate glass during injection molding is reduced, so that when the frame is integrally molded to the plate glass by injection molding, undesired breakage of the plate glass is suppressed.

Abstract: A resin containment and injection system includes a tool, a resin storage well provided in the tool, a composite layup location provided on the tool and a vacuum bagging film provided over the resin storage well. The vacuum bagging film is configured to define a volume in the resin storage well responsive to establishment of a pressure equilibrium across the vacuum bagging film and substantially eliminate the volume responsive to application of positive pressure against the vacuum bagging film.

Abstract: A system (50) is provided for the production of elongated comestible products such as hot dogs, without the use of traditional casings. The system (50) includes a circular pattern of arrays (92) of elongated, open-ended, extruded synthetic resin cooking tubes (94, 96) within a rotatable cylindrical heating drum or housing (70). The tube housing (70) and arrays (92) are incrementally rotated and at each stop position certain of the tubes (94, 96) are filled with portions of meat emulsion (590) and alternating plugs (208), while previously filled tubes (94, 96) containing cooked product are unloaded, and other unfilled tubes are internally coated with a lubricant (e.g., a mixture of lecithin and vegetable oil). Energy exchange media such as hot water and/or steam are used within the housing to continuously cook the emulsion portions within the tubes (94, 96) to the desired extent.

Abstract: In a method of operating an injection molding machine of a type having an injection plunger for pushing melt from an injection space anteriorly of an injection plunger into an injection mold, a plasticizing screw of an extruder is continuously operated to continuously feed melt through a melt channel into the injection space. A passage through the melt channel is closed to allow backup of melt backwards into the extruder, and the injection plunger is moved forward to inject a shot amount from the injection space into the injection mold.

Abstract: A system is provided for forming solid ink sticks comprising a molten ink delivery station for introducing molten ink material into a forming tub to form a solid ink stick. The forming tub includes an open top for receiving the molten ink material and a cavity defining a lower portion of a solid ink stick shape. The system includes a top surface conditioning station for altering the top surface of the ink material introduced into the cavity of the forming tub.

Abstract: An injection-compression molding apparatus for producing a shaped plastic part has a first mold plate and a second mold plate, which delimit a component cavity and between which there is a gap in the non-closed state. The apparatus further comprises a plastics compound feeding arrangement for introducing plastics material through the gap into the component cavity, having a gate cavity which is substantially separated from the component cavity when the gap is closed.

Abstract: An extrusion-based injection molding system is designed for use in food processing applications. Interior surfaces, such as the barrel exit line and/or fill line, of the system may be coated with a friction-reducing agent.

Abstract: A mold for a use of making a fuel cell separator comprises: a first flow path forming portion to form a cooling medium flowing path, or to form an oxidizing gas flowing path, or to form a fuel gas flowing path; and an injection gate to shoot out a forming material settled on the first flow path, and/or disposed at near place with the first flow path.

Abstract: Active decompression to prevent melt drool from a mold (12, 14) or runner system (20) is achieved through the selective coupling and de-coupling of an injection piston (34) to a plunger (38). Following successive injection (FIG. 5a) and hold phases (FIG. 5b) of an injection molding process (FIG. 5), the runner and channel system is partially de-compressed (FIG. 5c) by drawing back together, over a short distance, the plunger (38) and the injection pressure (34) as one unit. The injection piston is then mechanically de-coupled from the plunger (FIG. 5e), with the injection piston (34) withdrawn to essentially its final shot position, but minus a customary packing distance (?). Plastic melt (100), extruded into a shooting pot (28) positioned in front of the plunger (38), is permitted to push the plunger backwards, but now with minimal work expenditure. When the plunger again contacts (FIG. 5f) the injection piston (34), melt pressure now causes both units to be moved back to reach a final shot size volume.

Abstract: An object is to improve the quality of molded articles and enable stable molding to be performed. A plasticizing apparatus includes a cylinder member having a molding material supply opening at a predetermined position, a molding material being supplied into the cylinder member via the molding material supply opening; and a metering member rotatably disposed within the cylinder member and adapted to plasticize the molding material when the metering member is rotated. A gas-flow-forming medium hole is formed in the cylinder member at a predetermined position. An open-close apparatus (37) is provided so as to open and close the gas-flow-forming medium hole. Since the open-close apparatus (37) is provided, a gas-flow-forming medium outside the cylinder member can be caused to enter the cylinder member.