Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/18—Feeding the material into the injection moulding apparatus, i.e. feeding the non-plastified material into the injection unit
  • B29C45/1816—Feeding auxiliary material, e.g. colouring material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/71—Feed mechanisms
  • B01F35/714—Feed mechanisms for feeding predetermined amounts
  • B01F35/7141—Feed mechanisms for feeding predetermined amounts using measuring chambers moving between a loading and unloading position, e.g. reciprocating feed frames

Definitions

• This invention relates to the field of injection molding of plastics.
• plastic granules most commonly in pellet form, are heated to their melting point and the resulting liquid is injected into a die by means of an auger-like device.
• Most pellets are color ⁇ less.
• the pellets when ground and heated, the pellets cause a significant level of friction to be built up in the auger decreasing the efficiency of the molding process.
• color ⁇ ing additives and/or lubricants may be added to the pellets, either as the pellets are formed or prior to their melting.
• Andrews U.S. Pat. No. 3,972,665
• Bailey U.S. Pat. Nos. 2,393,452 and 2,443,289
• Rowland U.S. Pat. No. 4,356,139, provides for spraying of liquid lubricants upwardly, under high pressure by a plurality of nozzles onto pellets before and while entering a heating means.
• a further aspect of this invention is to provide means in the dispensing apparatus for slidably delivering said powder from the first to the second of said points.
• An additional aspect is to provide means in the dispensing apparatus which synchronize the slidable means with the blast of air and further provide for adjustment of the rate at which the air blast providing means and the slidable means operate.
• a latter aspect of the invention provides means by which the amount of powder delivered to said slidable means may be varied.
• FIG. 1 is a schematic diagram of the dispensing apparatus embodying the invention
• FIG. 2 is an elevational view, partially in sec ⁇ tion, of the apparatus shown in FIG. 1;
• FIG. 3 is a plan view of the apparatus shown in FIG. 2;
• FIG. 4 is an enlarged sectional view taken along the line 4-4 in FIG. 3;
• FIG. 4A is a plan view of a modified slide.
• pressurized air is supplied via line 1 to the apparatus.
• the pressure may suitably be between 80 and 150 psi.
• the air supply is diverted at junction 2 between a regulator 3 for slide operation and a regulator 4 for air blast operation for transporting the powder to the throat 34 of a hopper 35 containing granules of thermoplastic material to be melted and molded for injection in an injection molding machine.
• the air supply line 3a communicates with a two-way air valve 5 which in turn operates a pneumatic cylinder 6.
• This cylinder when injected with air, moves a slidable, rectangular delivery device (a "slide”) 7 to the right, from a first position, shown in FIG. 1, to the second position.
• Air supply line 4a communi ⁇ cates with the slide 7 and a delivery tube 8 at the second position, and provides a blast of air in a downward direc ⁇ tion.
• the tube 8 then communicates with the throat 34 of the hopper 35 on an injection molding device (not shown) .
• a switch 9 is tripped by a switch actuator 27 when said slide 7 is pushed to the second position.
• the switch 9 then activates air supply valve 4b, providing the air blast when the slide 7 is in the second position.
• a time delay relay 10 and pulse timer circuit 11 function to activate and control the rate of operation of the pneu ⁇ matic air cylinder 5.
• the timer 11 may be controlled from an external machine, e.g. in response to the displacement of the auger of the injection molding machine via a machine actuator 26 which operates a cycle switch 28.
• the timer 11 may be a counter having means to output a control pulse at different counts or number of closures of the cycle switch 28. Alternatively an internal clock in the timer with a variable rate clock may be used to drive the counter. Controls of the clock rate and delay in the time delay relay 10 are provided at 29 and 30 on the front panel 16 and on the time delay relay 10 respectively.
• a generally cylindrical reservoir or container 12 to which the powder may be added.
• a wiper mechanism 13 or more specifically two wipers, radially mounted on an arm 37 which is connected to a central shaft 14.
• the wipers extend downward to wipe across the bottom of the container and across the outlet hole 21.
• the shaft 14 extends down ⁇ wardly to a motor 15 which drives the wipers 13.
• FIG. 2 shows the relationship between the cylin ⁇ drical container 12, wipers 13, shaft 14 and motor 15.
• the cylindrical container 12 is mounted above a lower con ⁇ trol box 16 which contains the pressure regulators 3, 4 (shown in FIG. 1) , associated pressure gauges 24, 25 and control knobs 31, 32 respectively, supply lines 3a, 4a, air valve 5, motor 15, timer 11 and associated con ⁇ trols 29, an on/off power switch 36, indicator lamp 40 and associated fuses 41. See FIG. 2.
• the cylindrical con ⁇ tainer 12 is mounted sufficiently above the box 16 as to provide room for the slide 7 and its mounting in a dual block-like arrangement 17 through which tube 8 traverses. See FIG. 4.
• the block arrangement 17 is fixedly attached to and includes an upper block 18, between which slide 7 moves. Bolts 19 provide the attachment.
• Air supply line 4a communicates through upper block 18 to the second position region 20.
• a movable and adjustable insert 38 in the slide 7 which changes the size (diameter) of the hole 22.
• the upper block 18 then is preferably domed to provide a passage for the air blast even when the insert extends over the air line 4a in second position 20.
• the position of the insert 38 is set by a bolt 39.
• the thickness of slide 7 is greater than the slide shown in FIG. 2 when the movable and adjustable insert 38 is used therein.
• cylindrical container 12 is shown with respect to its bottom opening 21 which coincides with an identical in diameter opening 22 in slide 7.
• Slide 7 is shown in the first position.
• switch 9 When activated by the pneumatic cylinder 6 the slide 7 pushes the slide, with the opening 22 filled with powder from container 12, thus forming a "charge", to the right to " the second position to define region 20.
• switch 9 is tripped which operates solenoid 23 (see FIG. 1) associated with valve 4b and causes a blast of air to be delivered via line 4a to, when the slide is in said second position, region 20 from above the region and therefore opening 22 at a time which coincides with said slide reaching said second position.
• a second timer also actuated by the cycle switch 28 may be used to actuate the solenoid 23 and initiate the air blast at a time when the auger is return ⁇ ing to its return position.
• the charge is thus blown down and out of the opening 22 (see also FIG. 4) out through tube 8 to the throat of the hopper at an adjustable pres ⁇ sure of between 0 and 75 psi controlled by the regulator 4 which may be observed at pressure gauge 24.
• the slide air pressure is also controlled by the regulator 3 and may be observed at gauge 25.
• Controls 31 and 32 for the regula ⁇ tors 3 and 4 are on the front panel 16.
• Slide 7 returns to the first position to receive another charge once the openings 21 and 22 are realigned.
• the opening 21 in the bottom of said cylindrical container 12 is closed by the solid portion of said slide 7.
• powder does not fall out the bottom of said opening 21 because it is closed by the upper portion of said lower block 17 until it reaches said second position.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=24107337

Family Applications (1)

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Citations (3)

Family Cites Families (3)

• 1984
  • 1984-03-07 AU AU26907/84A patent/AU2690784A/en not_active Abandoned
  • 1984-03-07 WO PCT/US1984/000360 patent/WO1985000994A1/en not_active Application Discontinuation
  • 1984-03-07 EP EP19840901302 patent/EP0155269A4/de not_active Withdrawn

Patent Citations (3)

Non-Patent Citations (1)

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