Apparatuses for forming objects

Abstract

An apparatus for forming an object from a dose of plastics comprises a die arrangement provided with a cavity for receiving said dose and with at least two parts that are reciprocally movable for shaping an undercut portion of said object, at least one fluid for applying a clamping force so as to keep said at least two parts in contact; said at least one fluid is such as to increase discontinuously said clamping force from an initial force that is applicable when said dose is substantially contained in said cavity to a final force applicable when said at least two parts shape said undercut portion.

1 . Apparatus for forming objects comprising a plurality of moulds that are openable and closable by means of a hydraulic device, each mould defining a forming chamber for forming an object, wherein said hydraulic device comprises a hydraulic circuit arranged for opening or closing a group of said plurality of moulds and a further hydraulic circuit distinct from said hydraulic circuit and arranged for opening or closing a further group of said plurality of moulds. 
     
     
         2 . Apparatus according to  claim 1 , wherein said group comprises a half of said plurality of moulds and said further group comprises a further half of said plurality of moulds. 
     
     
         3 . Apparatus according to  claim 1 , wherein each mould of said group is interposed between two consecutive moulds of said further group. 
     
     
         4 . Apparatus according to  claim 1 , wherein each mould of said further group is interposed between two consecutive moulds of said group. 
     
     
         5 . Apparatus according to  claim 1 , wherein said plurality of moulds is arranged in a peripheral region of a carousel rotatable around a rotation axis. 
     
     
         6 . Apparatus according to  claim 5 , wherein said rotation axis is arranged vertically. 
     
     
         7 . Apparatus according to  claim 1 , wherein said hydraulic circuit is provided with a pump. 
     
     
         8 . Apparatus according to  claim 7 , wherein said further hydraulic circuit is provided with a further pump. 
     
     
         9 . Apparatus according to  claim 7 , wherein said hydraulic circuit comprises a delivery conduit arrangement by means of which a pressurised driving fluid is conveyed by said pump to each mould of said group. 
     
     
         10 . Apparatus according to  claim 9 , wherein said plurality of moulds is arranged in a peripheral region of a carousel rotatable around a rotation axis and wherein said delivery conduit arrangement comprises an inlet conduit that is substantially parallel to said rotation axis. 
     
     
         11 . Apparatus according to  claim 10 , wherein said delivery conduit arrangement comprises an annular conduit into which said inlet conduit leads, said annular conduit extending around said rotation axis. 
     
     
         12 . Apparatus according to  claim 11 , wherein said delivery conduit arrangement comprises a plurality of distributing conduits that extend radially from said annular conduit. 
     
     
         13 . Apparatus according to  claim 12 , wherein said delivery conduit arrangement comprises a plurality of supply conduits arranged transversely to said distributing conduits in said peripheral region. 
     
     
         14 . Apparatus according to  claim 9 , wherein said further hydraulic circuit is provided with a further pump and wherein said further hydraulic circuit comprises a further delivery conduit arrangement by means of which a further pressurised driving fluid is conveyed by said further pump to each mould of said further group. 
     
     
         15 . Apparatus according to  claim 14 , wherein said plurality of moulds is arranged in a peripheral region of a carousel rotatable around a rotation axis and wherein said further delivery conduit arrangement comprises a further inlet conduit that is substantially parallel to said rotation axis. 
     
     
         16 . Apparatus according to  claim 15 , wherein said further delivery conduit arrangement comprises a further annular conduit into which said further inlet conduit leads, said further annular conduit extending around said rotation axis. 
     
     
         17 . Apparatus according to  claim 16 , wherein said further delivery conduit arrangement comprises a plurality of further distributing conduits that extend radially from said further annular conduit. 
     
     
         18 . Apparatus according to  claim 17 , wherein said further delivery conduit arrangement comprises a plurality of further supply conduits arranged transversely to said further distributing conduits in said peripheral region. 
     
     
         19 . Apparatus according to  claim 9 , wherein said hydraulic circuit comprises a return conduit arrangement by means of which said driving fluid is conveyed from each mould of said group to said pump. 
     
     
         20 . Apparatus according to  claim 19 , wherein said further hydraulic circuit comprises a further delivery conduit arrangement by means of which a further pressurised driving fluid is conveyed by said further pump to each mould of said further group and wherein said further hydraulic circuit comprises a further return conduit arrangement by means of which said further driving fluid is conveyed by each mould of said further group to said further pump. 
     
     
         21 . Apparatus according to  claim 9 , wherein said hydraulic circuit comprises a plurality of valves drivable for sending said driving fluid to corresponding moulds of said group. 
     
     
         22 . Apparatus according to  claim 21 , wherein said hydraulic circuit comprises a plurality of connecting conduits interposed between each valve of said plurality of valves and a corresponding mould of said group. 
     
     
         23 . Apparatus according to  claim 22 , wherein said hydraulic circuit comprises a return conduit arrangement by means of which said driving fluid is conveyed from each mould of said group to said pump and wherein each valve of said plurality of valves is operable between a driving position in which a respective connecting conduit of said plurality of connecting conduits is in fluid communication with said delivery conduit arrangement and a discharge position in which said respective connecting conduit is in fluid communication with a discharging arrangement connected to said return conduit arrangement. 
     
     
         24 . Apparatus according to  claim 21 , and further comprising a cam driving arrangement for driving said plurality of valves. 
     
     
         25 . Apparatus according to  claim 21 , wherein said plurality of moulds is arranged in a peripheral region of a carousel rotatable around a rotation axis and wherein the valves of said plurality of valves are positioned along a circumference arranged in said peripheral region. 
     
     
         26 . Apparatus according to  claim 25 , wherein the valves of said plurality of valves are equidistant along said circumference. 
     
     
         27 . Apparatus according to  claim 21 , wherein said further hydraulic circuit comprises a further delivery conduit arrangement by means of which a further pressurised driving fluid is conveyed by said further pump to each mould of said further group and wherein said further hydraulic circuit comprises a plurality of further valves drivable for sending said further driving fluid to corresponding moulds of said further group. 
     
     
         28 . Apparatus according to  claim 27 , wherein said further hydraulic circuit comprises a plurality of further connecting conduits interposed between each further valve of said plurality of further valves and a corresponding mould of said further group. 
     
     
         29 . Apparatus according to  claim 28 , wherein said further hydraulic circuit comprises a further delivery conduit arrangement by means of which a further pressurised driving fluid is conveyed by said further pump to each mould of said further group and wherein said further hydraulic circuit comprises a further return conduit arrangement by means of which said further driving fluid is conveyed by each mould of said further group to said further pump and wherein each further valve of said plurality of further valves is operable between a driving position in which a respective further connecting conduit of said plurality of further connecting conduits is in fluid communication with said further delivery conduit arrangement and a discharge position in which said respective further connecting conduit is in fluid communication with a further discharging arrangement connected to said further return conduit arrangement. 
     
     
         30 . Apparatus according to  claim 27 , and further comprising further cam driving arrangement for driving said plurality of further valves. 
     
     
         31 . Apparatus according to  claim 27 , wherein said plurality of moulds is arranged in a peripheral region of a carousel rotatable around a rotation axis and wherein the valves of said plurality of valves are positioned along a circumference arranged in said peripheral region and wherein the further valves of said plurality of further valves are positioned along a further circumference arranged in said peripheral region. 
     
     
         32 . Apparatus according to  claim 31 , wherein the further valves of said plurality of further valves is equidistantly spaced along said further circumference. 
     
     
         33 . Apparatus according to  claim 31 , wherein said circumference and said further circumference are concentric. 
     
     
         34 . Apparatus according to  claim 33 , wherein said further circumference is arranged inside said circumference. 
     
     
         35 . Apparatus according to  claim 31 , wherein the valves of said plurality of valves are angularly staggered with respect to the further valves of said plurality of further valves. 
     
     
         36 . Apparatus according to  claim 1 , wherein said plurality of moulds is shaped in such a way as to form said objects through compression moulding of doses of plastics. 
     
     
         37 . Apparatus according to  claim 36 , wherein said plurality of moulds is shaped in such a way as to obtain preforms of containers from said doses. 
     
     
         38 . Apparatus according to  claim 1 , wherein each mould of said plurality of moulds comprises at least two parts that are reciprocally movable for shaping undercut portions of said objects. 
     
     
         39 . Apparatus according to  claim 38 , wherein said at least two parts are movable with respect to one another along a substantially rectilinear trajectory. 
     
     
         40 . Apparatus according to  claim 38 , wherein said at least two parts comprise a first part and a second part. 
     
     
         41 . Apparatus according to  claim 40 , wherein said first part and said second part are mounted on a carriage movable parallel to an approach direction along which a die arrangement and a punch of said plurality of moulds move together to form said objects. 
     
     
         42 . Apparatus according to  claim 41 , wherein said carriage is slidingly drivable along a guiding arrangement parallel to said approach direction through a driving bar. 
     
     
         43 . Apparatus according to  claim 40 , wherein said first part and said second part are fixed respectively to a first supporting element and to a second supporting element. 
     
     
         44 . Apparatus according to  claim 43 , wherein said at least two parts are movable with respect to one another along a substantially rectilinear trajectory and wherein said first supporting element and said second supporting element comprise respectively a first sliding portion and a second sliding portion, that are movable with respect to one another parallel to said trajectory. 
     
     
         45 . Apparatus according to  claim 44 , wherein said first part and said second part are mounted on a carriage movable parallel to an approach direction along which a die arrangement and a punch of said plurality of moulds move together to form said objects and wherein said first sliding portion and said second sliding portion are slidingly movable along a bar of said carriage, arranged transversely to said approach direction. 
     
     
         46 . Apparatus according to  claim 45 , wherein said first sliding portion and said second sliding portion are provided with respective rotatable rollers, rotatable around respective rotation axes arranged transversely to said bar and to said approach direction. 
     
     
         47 . Apparatus according to  claim 46 , wherein said rotation axes are substantially orthogonal to said bar and to said approach direction. 
     
     
         48 . Apparatus according to  claim 40 , wherein said at least two parts are movable with respect to one another along a substantially rectilinear trajectory and further comprising a cam profile for driving said first part and said second part along said trajectory. 
     
     
         49 . Apparatus according to  claim 44 , and further comprising a earn profile for driving said first part and said second part along said trajectory. 
     
     
         50 . Apparatus according to  claim 49 , wherein said first sliding portion and said second sliding portion are provided with respective rotatable rollers, rotatable around respective rotation axes arranged transversely to said bar and to said approach direction, wherein said cam profile comprises a pair of tracks along which said rollers can run and which are arranged symmetrically with respect to a plane parallel to said approach direction. 
     
     
         51 . Apparatus according to  claim 40 , and further comprising a positioning arrangement for positioning said first part in a contact position wherein said undercut portions can be shaped. 
     
     
         52 . Apparatus according to  claim 44 , and further comprising a positioning arrangement for positioning said first part in a contact position wherein said undercut portions can be shaped. 
     
     
         53 . Apparatus according to  claim 52 , wherein said first part and said second part are mounted on a carriage movable parallel to an approach direction along which a die arrangement and a punch of said plurality of moulds move together to form said objects and wherein said first sliding portion and said second sliding portion are slidingly movable along a bar of said carriage, arranged transversely to said approach direction and wherein said positioning arrangement comprises a projection that projects transversely from said bar so that said first sliding portion can abut against said projection in said contact position. 
     
     
         54 . Apparatus according to  claim 53 , wherein said projection projects from an intermediate portion of said bar substantially orthogonally to a longitudinal axis of said bar. 
     
     
         55 . Apparatus according to  claim 54 , wherein said positioning arrangement comprises an elastic element arranged for pushing said first sliding portion against said projection in said contact position. 
     
     
         56 . Apparatus according to  claim 55 , wherein said elastic element comprises a helical spring wound around said bar. 
     
     
         57 . Apparatus according to  claim 51 , and further comprising a pressing element arranged for pressing said second part against said first part in said contact position. 
     
     
         58 . Apparatus according to  claim 57 , wherein said positioning arrangement comprises an elastic element arranged for pushing said first sliding portion against said projection in said contact position and wherein said pressing element comprises a further elastic element having stiffness less than said elastic element. 
     
     
         59 . Apparatus according to  claim 58 , wherein said further elastic element comprises a further helical spring wound around said bar. 
     
     
         60 . Apparatus according to  claim 52 , wherein, in said contact position, between said second sliding portion and said projection a gap is defined.