Module for supporting a vertical plunger

Abstract: An apparatus for supporting a plurality of vertical plungers comprises a plurality of modules (60). Each module (60) comprises a fixed frame (64), and movable frame (82), a servo motor (92) and a linear actuator for moving the movable frame (82) vertically. A supporting arm (62) is connected to the movable frame (82) and carries an assigned-to plunger (P).

Description: This invention relates to a module for supporting a plunger which is adapted to control flow of glass through an orifice in the bottom of a forehearth and to an apparatus comprising a plurality of such modules. In the manufacture of glass articles, it is common to provide a glass forehearth having a bottom with multiple orifices which are controlled by reciprocable needles or plungers in order to provide the necessary uniform weight of gobs. Plural needles and orifices are utilized in order to maximize glass production. Typical systems are shown in U. S. patents 1,529,948, 1,792,932, 1,926,764, 3,711,266, 4,478,631, 4,554,000, 4,581,054 and 4,793,849. In such systems it is common to manually adjust each plunger. Furthermore in such systems, the operating mechanisms for the plungers are often in overlying relationship to the plungers and therefore are subject to extreme heat conditions. Contaminants of oil or metal can jeopardize the purity of the molten glass. This problem has been solved by an apparatus shown in EP-A-0 612 698. The actuating servo mechanisms for driving the plungers are mounted on the side of the forehearth and, therefore, cannot contaminate the glass. Furthermore, they are somewhat protected from the heat of the glass. A problem arises from the individual weight of each plunger and support arm that is to be counterbalanced. This has been done by each an air spring acting on the arm to which the plungers and the actuators are connected. It is an object of the present invention to amend this mechanical system of driving the plunger. Accordingly, the invention provides a module for supporting a vertical plunger as defined in claim 1, and an apparatus as defined in claim 10. In this form, each servomotor is part of a module having a fixed frame and moves a movable frame for vertical movement. Each movable frame supports a plunger arm. The modules which are of elongated rectangular shape are mounted in side by side relationship with one another at one side of the forehearth. The fixed frame preferably has vertically spaced shafts. In the drawings, Figs. 1 to 8 show the apparatus of EP-A-0 612 698, and Figs. 9 to 23 are embodiments according to the invention. FIG. 1 is a part sectional elevational view of a multiple plunger glass feed system. FIG. 2 is a fragmentary plan view of the glass feed system. FIG. 3 is a fragmentary sectional view on an enlarged scale taken along the line 3-3 in FIG. 2. FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3. FIG. 5 is a fragmentary plan view of a modified form of the glass feed system. FIG. 6 is a fragmentary plan view of a further form of the glass feed system. FIG. 7 is an electronic schematic of the control system. FIG. 8 is a diagram of the range of motion of a plurality of plungers. FIG. 9 is a plan view of a mechanical system to drive the plungers, parts being broken away. FIG. 10 is a plan view on an enlarged scale of one of the modules shown in FIG. 9. FIG. 11 is a side elevational view of the module shown in FIG. 10, parts being broken away. FIG. 11A is a fragmentary part sectional side elevational view of portion of the module shown in FIG. 10. FIG. 12 is a sectional view taken along the line 12- 12 in FIG. 10. FIG. 13 is a sectional view taken along the line 13-13 in FIG. 12. FIG. 14 is a fragmentary sectional view on an enlarged scale taken along the line 14-14 in FIG. 12. FIG. 14A is afragmentary sectional view on an enlarged scale taken along the line 14A-14A in FIG. 12. FIG. 14B is a fragmentary sectional view taken along the line 14B-14B in FIG. 12. FIG. 15 is a fragmentary perspective view of a portion of the assembly shown in FIG. 12. FIG. 16 is a fragmentary view of a plunger and arm. FIG. 17 is a top plan view of the plunger and arm shown in FIG. 16. FIG. 18 is a view similar to FIG. 16 showing a cabinet surrounding the module. FIG. 19 is a fragmentary sectional view taken along the line 19-19 in FIG. 18. FIG. 20 is a plan view of another modified form of the invention. FIG. 21 is a plan view of another modified form of the invention. FIG. 22 is a plan view of a still further form of the invention. FIG. 23 is a plan view of another form of the invention. Referring to FIGS. 1-3 the glass feed system 10 is associated with a bowl 11 of a forehearth and is intended to support a plurality of plungers or needles 12 that function in connection with orifices 13 to control the flow of glass out of the orifices so that when associated shears, not shown, are used, the size and weight of the gobs so produced is consistent. In such mechanical system each plunger 12 is supported by a horizontal arm 15 that is connected to an actuator 16 of a servomotor controlled mechanism 17. Each arm further includes an air spring 18 associated with its respective arm 15 for balancing the weight of each plunger and its respective arm. The center lines of the plungers lie generally in a first plane. The arms 15 have the major portions thereof generally parallel and perpendicular to the plane of the plungers. A feedback system is provided to monitor the position of each individual needle independently of the other at all times and make corrections to the actual position of the needle if desired. The arms 15 are constructed and arranged in close proximity so that a minimum of space is utilized and so that the operating mechanisms are in lateral but close proximity to the bowl of the glass. Figs. 2, 5 and 6 show how the above requirments can be fulfilled. Referring to FIG. 3, the servomotor assembly comprises a welded drive housing 30 and includes a top bearing collar 31 an intermediate bearing collar 32 and lower bearing collar 33. A servo drive shaft 34 is rotatably mounted in the collar 33 by a duplex bearing 35 held in position by retaining nut 36. A welded drive post assembly 40 is mounted within the housing 30 and supports a planetary roller nut 41. The drive shaft supports a lead screw 42 that is associated with the servo nut 41. A coupling 43 connects the shaft 34 to the shaft 45 of the servo actuator 17. Coupling 43 is preferably of the keyless bushing type which provide a positive lock between servo actuator shaft 45 and drive shaft 34. Each air cylinder 18 that performs the function of an air spring is provided in close relationship to its respective servomotor assembly 17 and includes a cylinder housing 50 that has a base ring 51, a cylinder housing 52, a jam nut 53 and an upper cylinder weldment 54. An air spring column 55 extends between the shaft of an air spring and a respective arm. The multiple orifice plunger control system is made up of one to four separate mechanical systems, depending on the number of plungers to move the needles, depending on the number of needles that are present (1-4). Since each needle is a mechanically independent system, a separate motion control unit must be provided for each unit. Referring to FIG. 7, this unit consists of the motion controller, amplifier/driver, servo actuator (which in this case, is an AC servomotor), and a feedback device (resolver) inside the motor housing. At this level each control system is completely independent. The feedback device is mounted on the back of the servomotor and serves a dual purpose. It provides position information to the motion controller which is used to determine both the motor rotor position and the position of the plunger. The rotor position is needed for communication of the motor since it is an AC servomotor. The position of the plungers, is derived from the resolver, and is a relative offset from a fixed reference. The fixed reference is the end of travel of the lead screw in the extended position. The amplifier/driver is simply a power amplifier. It converts the torque command inputs to the appropriate voltage and power level for the AC servomotor connected to it. The motion controller has in its memory a motion profile, generated by the supervisor, that dictates where the particular needle mechanism should be in relationship to the master clock and reset signals. The actual position of the mechanics is determined from the feedback device. The motion controller uses both the actual position, the commanded (profile) position and the rotor position to generate the torque commands that go to the amplifier. The absolute torque command is calculated as a function of the actual and commanded positions. The torque commands that are sent to the amplifier are in a commutated form for phase A and B. The amplitude of the absolute torque command for motor phases A and B is adjusted based on the motor rotor position. The torque command for phase C is calculated in the amplifier, it is the sum of the torque command of A and B. The supervisor calculates the motion profile for each of the motion controllers based on input from the user. The profile is a position-to-position relationship between a master clock and the desired position of each needle. The same profile is normally used for each needle, but a unique profile for each needle is possible if the situation demands it. The needles are normally synchronized to operate at the same time, reaching the extremes of their motion at the same point in time. The vertical distance is normally the same also. Because of glass flow differences between the orifices, the needle typically operates at different elevations as shown in FIG. 8. This difference in height is used to balance the weight of the gobs produced by the individual orifices. The height adjustment is controlled by the supervisor. If a change in the height relationship between the needles is commanded, by either operator input or from an automatic gob weight control system, the motion profile for the effected needle or needles is recalculated by the supervisor. The profile is then written into the memory of the motion controller. The supervisor is then responsible for synchronizing the change to the new profile so that all the effected motion controllers switch at the same time without a disruption of production. Whereas the above description of Figs. 1 to 8 relates to the general principles used in the apparatus for supporting the vertical plunger, the amended mechanical system to drive the plungers P is shown in FIGS. 9-23. The servomotors are part of compact modules 60 which are mounted in closely spaced side by side relation adjacent the forehearth. Each module 60 supports a horizontal plunger arm 62 and a plunger or needle P. In the form shown in FIG. 9, the plane of the vertical center lines of the plungers is parallel to the axis of the forehearth F. Referring to FIGS. 10-17, each module 60 consists of a fixed frame 64 (FIG. 11) that includes a rectangular bottom plate 66, a rectangular top plate 68 and spaced vertical uprights 70, 71 connected to the plates 66, 68 by bolts. A first shaft 72 extends between the plates 66, 68 and has its ends extending into recesses 74, 76. A second shaft 78 comprises a cylindrical bearing portion 78a and an integral elongated portion 79 along the cylindrical portion 78a which is bolted to the uprights 71. Shaft 78 extends upwardly from bottom plate 66. A movable frame 82 is supported for vertical movement on the shafts 72, 78 and consists of a spaced vertical frame members 84 (FIGS. 13, 15), each of which includes upwardly extending frame extensions 86 and downwardly extending frame extensions 87 at one end adjacent the plunger arm 62. Frame extension 86, 87 support vertically spaced bearings 110 (FIG. 12) for shaft 72. Transverse bars 89 at the other end of frame 82 extend between the frame members 84 and support a bearing 90 for shaft 78. A servomotor 92 is preferably formed with vertical fins 94 (FIG. 11) on its housing to maximize cooling of the motor during operation where the mechanism is exposed to the high heat of the forehearth. The servomotor 92 (FIG. 11) includes an output shaft 96 that extends through a brake 98 through upper plate 68 between the uprights 70 to a coupling 100 (FIG. 12) that is connected to a vertical lead screw 102. The upper end of the lead screw 102 is rotatably supported by a bearing 101 that, in turn, is supported by a bearing housing 103 fixed between uprights 70, 71. The lower end of the vertical lead screw 102, extends through a planetary helical roller nut 104. The nut 104 is mounted on plates 106, 108 between side plates frame members 84 (FIG. 13) such that when the lead screw 102 is rotated the nut 104 is translated vertically (FIG. 15) and moves the frame 82 (FIGS. 13, 15) consisting of member 84, 86, 87 and plunger arm 62 vertically. Shaft 72 extends through the bearings 110 and thus assists in vertically guiding the movable frame 82 and also counteracts the weight of the plunger arm 62 and plunger P. A bearing 90 is mounted at the other end of the movable frame 82 assists in the guiding of the vertical movement of the frame 82 as well as counterbalancing the forces due to weight of the plunger P and plunger arm 62. An adjustable stop 116 is provided on the lower plate 66 and functions as a stop for the nut 104 in the event the movable frame 82 is moved downwardly to a position which might damage the forehearth F. As shown in FIG. 11, a manifold 119 with associated hoses as provided for supplying lubricant to the bearings 90, 101, 110 and ball roller nut 104, through line 120. Referring to FIGS. 11a and 13-15 a coupling 118 which is rectangular in cross section is mounted between the frame members 84 and telescopically receives a plunger arm 62. As shown in FIGS. 14, 14A, the plunger arm 62 is pivoted to the coupling 118 by a bolt 121 such that the plunger 62 can be tilted upwardly out of the way for service on the forehearth F. An adjustable stop 122 is provided on a plate 66 for adjusting horizontal position of the plunger arm to ensure proper vertical movement of the plunger P. The plunger P is preferably coupled to the plunger arm 62 by quick release lock 126. Referring to FIGS. 11, 18, 19, a shield housing or cabinet 150 is preferably provided around the modules 60 to protect the modules 60 from the heat of the forehearth in a manner in which the arms 62 extends outwardly from the cabinet. The cabinet 150 includes a frame 151 on which side walls 152, 154, end walls 156, 158 and top and bottom walls 160, 162 are removable. The end wall 156 has vertically elongated openings 164 through which the arms 62 extend. A heat shield 166 is provided forwardly on each module 60 and moves with the module 60 as the movable frame 82 and associated arm 62 is moved up and down and is spring loaded by springs 168 on a fixed plate 170 for sealing engagement with the opening of wall 156 in order to protect the modules 60 from the high heat of the glass and the forehearth. In operation the servomotor 92 is actuated to move its respected plunger P. Each module 60 is independent of the other as in the previous form of the invention and is controlled individually as in the previous form of the invention. In the arrangement shown in FIG. 9, the vertical axes of the plungers lie on a plane at a right angle to the axis of the forehearth F. The plunger arms 62a, 62b and 62c each have straight and parallel end portions. The center module 60 has the entire arm 62b straight while the arms 62a and 62c have the major central portions at a small angle to the arm 62b such as to bring the plungers thereon into the vertical plane previously described. In another arrangement as shown in FIG. 20 the plane of the plungers, that is the plane containing the vertical axes of the plungers is perpendicular of the axis of the forehearth F. In order to achieve such an arrangement, the center plunger arm 62e is straight and the outer arms 62d and 62f have their central major portions at a small angle to the straight arm 62e and have their end portions which are connected to the plungers at an obtuse angle to the central portions in order to bring the plungers into the single plane. The arrangement shown in FIG. 21 is identical with that shown in FIG. 9 except that four plungers are shown in a single plane. In order to achieve this arrangement the additional plunger arm 62g of the fourth module 60 has an end portion that is straight and coupled to the fourth module 60. Plunger arm 62g has a central portion that is at a greater angle than arms 62d and 62f to the straight end portion which is connected to the fourth module. The other end of arm 62g angled to present the fourth plunger into the desired position. In the form shown in FIG. 22, two plungers are provided by respective module 60. Each plunger arm 62h, 62i has straight end portions and angled major central portions such that the plane containing the vertical axes of the plungers is parallel to the axis of forehearth F. In the form shown in FIG. 23, the plane defined by the axes of the plungers is at a right angle to the axis of the forehearth. In order to achieve this that the plunger arms 62j, 62k have straight portions connected to the module 60, major central portions inclined to the ends at the one end and end portions connected to the plungers which are at a greater angle to the central portions angled at the other end. It can be seen that in each of the forms shown in FIGS. 9-23, the modules are rectangular as viewed in plan view and have a length several times the width so that the modules are very compacted and occupy minimal space. As a result, they can be closely spaced on one side of the forehearth as shown in FIGS. 9, 20-23, thus leaving room for the tube turning mechanism, gas burners, and shear mechanisms, while at the same time permitting ambient air to cool and thereby protect the mechanisms of the modules. It can be further seen that in all the forms of the invention, at least some of the arms are circuitous as viewed in plan view between the connection to the respective plungers and the connection to respective servo controlled linear actuators. In other words, each circuitous arm does not lie in a straight line between the connection to the plunger and the connection to the servo controlled actuators. As a result, the use of circuitous arms and the compact configuration of the actuators as viewed in plan view enable the actuators and arms to be in closely spaced relationship in a relatively small area such that the remaining area of the forehearth will be available for the numerous mechanisms used for glass delivery.

Claims: A module for supporting a vertical plunger (P) which is adapted to control flow of glass through an orifice in the bottom of a forehearth, comprising a first fixed frame (64) and a second movable frame (82), a servo motor (92) mounted on said fixed frame and a lead screw (102) connected to said servo motor (92) and rotably mounted in said first fixed frame (64), said first fixed frame (64) being arrangeable adjacent the forehearth and including means (72, 78) for guiding said second movable frame (82) in vertical direction, said second movable frame (82) being movably mounted on said guiding means (72, 78) of said fixed frame (64) and being carried by a nut (104), threaded on said lead screw (102), a plunger arm (62) being fixed to said movable frame (82) and suspending said plunger (P). The module set forth in claim 1 wherein said means for guiding said movable frame comprises spaced shafts (72, 78) which make part of said fixed frame (64), and bearings (90, 110) on said movable frame (82) that are supported along said spaced shafts (72, 78). The module set forth in claims 1 or 2 wherein said fixed frame (64) comprises a base plate (66), an upper plate (68) and said shafts (72, 78) extending between the plates, said servo-motor (92) being mounted on said upper plate (68). The module set forth in any of claims 1 to 3 wherein said movable frame (82) includes vertically spaced frame members (84), said nut (104) being mounted between said vertically spaced frame members (84). The module set forth in any of claims 1 to 4 wherein said servo-motor (92) has an output shaft (96) which extends through a brake (98), a coupling (100) connecting said shaft (96) to said lead screw (102). The module set forth in any of claims 1 to 5 wherein said plunger (62) is connected to said second movable frame (82) by means (118, 121) which cantilever said plunger arm (62) and permit pivotal motion of the plunger arm vertically away from the orifice. The module set forth in claim 6 wherein pivotal motion of the plunger arm (62) toward said orifice is limited by an adjustable stop (122) for adjusting the horizontal position of the plunger arm. The module set forth in any of claims 1 to 7 wherein a quick release lock (126) is provided for suspending said plunger (P). The module set forth in any of claims 1 to 8 including heat shield means (166) positioned between the plunger arm (62) and the module (60) for shielding the module (60) against heat. An apparatus for supporting a plurality of vertical plungers such that the axes of said plungers (P) lie in a single plane, said apparatus comprising a plurality of modules (60) according to any of claims 1 to 9, placed in closely spaced side by side relationship. The apparatus set forth in claim 10 comprising a cabinet (150) enclosing said plurality of modules (60), the plunger arms (62) of the modules extending through vertical openings (164) in the cabinet (150). The apparatus set forth in claim 11 comprising the features of claim 9 wherein each heat shield means (166) is carried by a respective movable frame (82) and is in sliding engagement with said cabinet (150)at the respective vertical opening (164) which is covered by such shield means, and wherein each movable frame (82) carries a plate (170) having springs (168) mounted thereon for urging the heat shield means (166) against an internal surface of said cabinet (150) surrounding said vertical opening (164). The apparatus set forth in any of claims 10 to 12 wherein at least some (62d, 62f, 62g, 62h, 62i, 62j, 62k) of said plunger arms (62) are non-linear configured so that the plungers (P) are disposed in a single plane.

Inventors: DIFRANK FRANK J, LEIDY WAYNE D, DIFRANK, FRANK J., LEIDY WAYNE, D.
Applicants: OWENS BROCKWAY GLASS CONTAINER, OWENS-BROCKWAY GLASS CONTAINER INC.
Application year: 1997
Main classification: C03B7
IPC codes: G05D7, H02K7, C03B7