MXPA97000513A

MXPA97000513A - Servo percu mechanism

Info

Publication number: MXPA97000513A
Application number: MXPA/A/1997/000513A
Authority: MX
Inventors: Wayne Leidy D
Original assignee: Owensbrockway Glass Container Inc
Priority date: 1996-02-07
Filing date: 1997-01-20
Publication date: 1997-08-01

Abstract

The present invention relates to an apparatus for forming a mass of molten glass in a hollow article, characterized in that it comprises: plunger means having a striker to contact a mass of molten glass to give it the shape of a hollow article a driven electro-servo guide screw connected to the striker means for transferring the striker means along a rectilinear stroke towards and away from the glass mass to put the striker in contact and remove it from contact with the glass mass; control means for controlling the operation of the driven electro-servo guide screw to control the straight stroke towards and away from the glass mass, the control means comprise a firing position sensing resolver for detecting the position of the firing pin means in all places along the road

Description

SERVO PERCUTOR MECHANISM C AM P O Y AN T E C E D E N G L I NVE N C L I N The present invention relates to an operator or piston suitable for use in glass molding machines, for example those of type I.S. in the formation of molten glass masses in hollow balloons for subsequent formation in blown glass articles. The hammer is activated by a servo-driven elector guide screw which works in conjunction with a position detecting device to provide firing pin position information. Although the immediate application of the process of molding glass consigns in the first place the process "blowing and pressing the narrow neck" ("NN PB") the applications of other types of processes, such as "pressing and blowing", (" P &B ") or" blowing and blowing "(" B &B ") will be evident as described below.

Glass molding machines of the type I.S. They are well known in the industry. These machines have a number of individual molding units, or sections, each REF: 23797 of which receives masses of molten glass from a common source and feeds its output to a common carrier. For the NNPB process, each section has at least one hollow balloon forming mold in which the masses of molten glass are transformed into hollow glass balloons and at least one blow mold in which the hollow balloons are blown to the required form.

In the NNPB process, hollow balloons are formed when a mass of molten glass is placed in the mold cavity of a pressure moulder and pressed by a hammer mechanism against the walls of the mold cavity, simultaneously forming the internal surface of the mold. hollow balloon (dictated by the shape of the hammer head) and the outer surface of the hollow balloon (dictated by the shape of the mold cavity). A conventional striker is usually made of a cylinder located under the pressure die and a piston in the cylinder that moves in and out of the mold cavity with the introduction of fluid under pressure into the cylinder. The piston rod projects from the piston into the mold cavity and arranges to carry the hammer, therefore the movement of the piston causes the movement of the firing pin in and out of the mold cavity.

In a conventional NNPB process, the piston typically uses air pressure to move the striker within the mold cavity so that a hammer head pressed to the striker presses the molten glass mass into the shape of the mold cavity. After the pressure of the molten glass mass is complete, the same air under pressure is then used to move the striker completely out of the mold cavity to the "striker down" position so that the hollow balloon can be moved to the next station. After the hollow balloon moves to the next station to be blown into a blown glass article, the firing pin moves to an intermediate "loading" position while the next molten glass mass is placed in the mold cavity, and the process is repeated.

The disadvantages of such systems are that they stir up factors such as precise control of air pressure performance, properties of liquid glass (which are constantly changing), and the quality of hollow balloons produced due to individual characteristics of each hammer. For example, the pressure exerted on the glass in a conventional pneumatic system is typically controlled by a pressure regulator. The change of one pound (0.4536 Kg.) In the control of air pressure results in twelve pounds (5.4432 Kg.) Of change in the pressure exerted. Consequently, any error in the control of the air pressure is also amplified by a factor of twelve.

In addition, the variables related to the movement of the hammer, such as the static pressure on the mass of molten glass and the velocity of the percus, typically depend on the time axis. That is, in a conventional process, the striker maintains a certain position for a calculated period of time and then moves to the next position, independent of the dynamics of the system. This requires precise synchronization of the delivery of the molten glass mass, the movement of the firing pin, and the transport of the hollow balloon, which is very difficult at best, and does not provide feedback for the correction of the system during the operation.

Previous inventions, such as that described in US Patent No. 5,236,485, attempt to eliminate such problems by using the position of the striker instead of the pneumatically controlled motion of the striker dependent on the time variable. In that patent, Le eringhaus teaches a hammer activated by a "hydraulic-elector control system". A piston and cylinder arrangement is used when the movement of the firing pin is controlled by the hydraulic fluid. A valve is electrically controlled to increase or decrease the prescribed amounts of hydraulic fluid from both ends of the piston, allowing for all intermediate positions of advance and retraction of the striker to be available. The current position of the hammer relative to the cylinder is monitored and compared to predetermined stored values, ie the desired positions, thus allowing feedback to dictate the function of the hydraulic control valve and finally the position of the firing pin. This eliminates the time variable in the equation, allowing a process to make glass more accurate and efficient.

While the use of a hydraulic firing pin triggers the problem inherent to the time dependence in the previous technology, any dependent system in the hammer position is critically dependent on the accuracy of the device's position detection components, that maybe it's not always the most accurate. The invention of Le eringhaus still relies on the detection of traditional position and the indication of the firing pin, that is, a detector of the coil and core type. A coil and core type detector is disclosed in US Patent No. 4,613,352 issued to Mannfred Krum e.

In the Krumme patent, a ring-shaped core is transported by a rod of the piston mounted on the hammer of the glass molding machine. The core forms an active element for changing the inductivity of a coil which is arranged in a ring-like armature between a cylinder and a guide cylinder for the firing pin. During each hammer work stroke, the maximum insertion depth in the mold is measured and used to generate an analog electrical signal. The signal is then compared to a reference value which, in turn, provides an adjustment value to adjust the mass of molten glass before it is removed from the mold. However, a disadvantage of the coil and core type detector is that the linear position of the firing pin can not be measured for the full impact of the firing pin.

The descriptions of the aforementioned US Patents 5,236,485 and 613,352 are incorporated herein by reference BRIEF DESCRIPTION OF THE INVENTION The present invention avoids any inherent problem related to the use of hydraulic pressure and / or air to control the movement of the striker while at the same time increasing the accuracy of the hammer displacement measurement. The device mentioned here provides greater control over the movement of the striker, while increasing its versatility as in the types of operations available.

One aspect of the present invention relates to the movement of the firing pin. Instead of a hydraulically controlled system, the movement of the firing pin in the preferred embodiment is made possible by a guide screw which is placed inside the cylinder of the existing firing pin. Using a cyclic reset motor and an "inlet and outlet" guide screw, the unit can be small enough to fit within the space allotted for the standard hammer cylinder. This type of servo-driven guide screw, also known as a linear actuator, is disclosed in U.S. Patent Application Serial No. 08 / 125,495, currently assigned to Exlar Corporation of Chanhassen, Minnesota, and is incorporated herein by reference. .

Another aspect of the present invention is the use of a position detector to determine the position of the striker and then use the position information for feedback to the system controller. Using the position information as feedback or feedback, the position of the firing pin can be adjusted according to the dynamics of the system. Such use of the position information greatly increases the accuracy over a conventional system that controls the position of the striker using the time factor alone and does not make adjustments during the work cycle. A resolution device is used to provide both the switching information about the motor as well as the precise information of the firing pin position. The effective resolution of this device when coupled to a guide screw is at least an order of magnitude better than the coil and core detectors currently used in the industry. Furthermore, considering that most coil and core detectors are good for only a limited range of firing strike, the resolving device provides information about the full range of cylinder movement. The glass hammer of the present invention uses the aforementioned aspects to operate in a variety of modes during the different parts of its operation cycle.

When there is no glass in the mold chamber, the control of the increased position of the firing pin is used to stop the forward movement of the hammer very close to the limit of the mechanical advance of the cylinder. When the striker reaches a predetermined safety point (as indicated by the position information), the system controller issues a stop signal to the striker. This prevents damage that could be caused by allowing the cylinder to drive itself forward, within the wall of the mold chamber.

During normal operation (when the glass is present in the mold chamber) the hammer will stop near the position of the set point because the firing pin makes contact with the molten glass mass first. When the hammer begins to penetrate the glass mass, then the movement of the firing pin will be restricted by the volume of molten glass in the mold chamber. The depth of penetration of the hammer into the glass will depend on the amount of glass in the mold chamber (specifically, the depth is inversely proportional to the amount of glass). The molding pressure is dictated by the torsion of the motor and mechanical screw (since the force exerted by the guide screw on the firing pin is a product of the torsion generated by the engine, it is possible to control the pressure by controlling the torsion applied by the motor to the guide screw). While the weight of the glass mass can not be measured directly, changes in the weight of the glass mass can be measured by closely monitoring the penetration depth of the firing pin. This information can then be used as a signal to reduce the weight of the glass mass. The ability to precisely control the molding pressure translates into more accurate measurements from cycle to cycle, since the variation in molding pressure has been minimized.

The molding pressure is maintained for a calculated period of time. When commanded, the hammer moves down to a position where the hammer is clear of the cavity and throat of the mold. After the hollow balloon is transferred, the firing pin moves to the "load" position. Both movements of the hammer are governed exclusively by control of the position. The torque control is applied only when the firing pin is moving upwards in contact with the glass.

The "hammer down" position and the "load" position can be controlled electronically. For a job change, the operator only needs to enter the new firing pin position in the system, even during the operation. Since the "load" position does not need to be determined by the cartridge, the construction of the firing pin cartridge can be simplified. In fact, for the processes of "pressing and blowing" and "pressing and blowing the narrow neck", the cartridge becomes only a shirt to control the alignment. of the hammer. However, to "blow and blow", the cartridge must still incorporate a pneumatic aspect to blow the hollow balloon to the shape of the mo-1 cavity.

Accordingly, it is an object of the present invention to provide a striker for the glass forming machine that is precisely controlled by a guide screw and an accompanying motor.

It is still another object of the present invention to provide a more accurate position sensing device, ie, accurate enough to provide information about the full range of the hammer strike and allow control of the weight of the melted glass mass.

For a further understanding of the present invention and the objects of this invention, • attention is directed to the drawings and the following brief description thereof, to the detailed description of the preferred embodiment, and to the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a hammer mechanism in accordance with the preferred embodiment of the present invention.

FIG. 2 is a view of the amplified cross-section of the lower portion of the striker mechanism of Figure 1.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The firing pin or piston assembly, s in ia Fig. 1, includes the main cavity 110 which is formed by means of the cylindrical outer wall 130 and the base 140. The cartridge 176 houses the head of the striker 171 and the striker 175. The cavity of the mold (not s) in which the molten glass mass is extracted, is of standard construction and is fixed to the upper part of the cartridge 176. The head of the firing pin 171 is attached to the firing pin 175 by means of the fixing ring 172, which can be formed of two separate pieces. The head of the striker 171 is furthermore attached to a connecting rod 160 using the retaining nut 180. The assembly of the striker 100 includes the inner cylinder 210 which is formed by a magnetic material and which is supported in a rotatable manner with respect to the outer wall 130. The bearings 150 allow smooth rotation of the inner cylinder 210 with the outer wall 130 during operation. The toothed cylinders of the striker 190 are attached to the rod 160, better s in Fig. 2. The motor assembly 200 includes the fixed part of the motor 205 and the magnets 206 which are mounted to the outer surface of the inner cylinder 210 to form an armature with the inner cylinder 210. The fixed part of the motor 205 is held and supported by the outer wall 130 and surrounds the inner cylinder 210. The system controller (not s) made of conventional construction, selectively drives the part fixed motor 205 to rotate the armature in one direction or in another, depending on the function required.

The inner cylinder 210 containing the threaded inner surface 211, the thread that is engaged by toothed cylinders of the firing pin 190. The connecting rod 160 engages with the toothed cylinders of the firing pin 190 such connecting rod 160 moves axially with the inner cylinder 210 with the rotation of the inner cylinder 210. The assembly of the striker 100 described herein which converts the rotary input into linear movement using a spiral screw 1-he 1 icoi da 1, in common form referred to as "inlet and outlet guide screw. ", is similar to those described in US Patents 4,048,867 and 4,576,057, both of which are incorporated herein by reference.

Servomotor 200 and position detecting device 220 are connected to the system controller (not s) by means of internal wiring 240, connector 230, and outer wiring 241.

There are three main positions of the firing pin 175 during the normal operation of the striker 100 assembly. The first position is referred to as the "load" position s in Fig. 1. The load position is located between the forward position of the striker 175 (where the striker 175 would now make contact with the front wall of the mold cavity, not s, when the mass of molten glass was not present) and the most backward position. The second position is the "press" position; this is the position of the hammer 175 when it comes into physical contact with the molten glass. This is approximated to the forward position of the hammer 175 (depending on the amount of molten glass in the mold cavity). The final position is the "hammer down" position, which is the backward position of the hammer 175. The operation of the hammer assembly 100 and its use of the three main positions are as follows.

The portion of the NNPB process relevant to the present invention begins with the striker 175 in the "load" position as shown in Fig. 1. A mass of molten glass (not shown) is released to the hollow balloons forming the cavity. of the mold (not shown) and the cover of the mold cavity (not shown) is closed. A signal is sent from the system controller 230 through the external wiring 241, the connector 230, and the internal wiring 240, thus the assembly of the actuating servomotor 200 and motivating the inner cylinder 210 to rotate. The threaded inner surface 211 of the inner cylinder 210 engages the toothed cylinders of the striker 190 which are attached to the rod 160, thereby moving the striker 175 forward towards the mass of molten glass (not shown) contained in the mold cavity (not shown). The resolution device 220 continuously replaces the information despite the axial position of the striker 175 to the system controller (not shown). When the striker 175 moves forward it eventually makes contact with the molten glass in the mold cavity (not shown).

This is the second position, known as the "push" position.

When the firing pin or piston 175 begins to penetrate the glass mass (not shown), the position control of the firing pin 175 is interrupted and the torsion control is used. The change of position control to torsion control is necessary to avoid potential problems due to the amount of glass in the mold cavity (not shown), which could vary in volume. Less glass melted in the mold cavity could result in imperfect finishes; More glass in the mold cavity could result in the mold cavity being forced to open by too much pressure.

The depth of penetration of the hammer 175 into the glass during the process pressure phase depends on the molding pressure and the amount of glass in the mold cavity. The molding pressure is an amount derived from the torque of the motor and the mechanics of the screw. The equation to calculate the pressure is: 2 p Tm W - < ? where W is the molding pressure, Tm is the torque of the motor, p is the head of the screw, and e is the efficiency of the screw. Alternatively, the molding pressure can be measured directly by connecting a strain gauge to the rod 160.

With the monitoring of the increased axial position, the weight control of the glass mass can be achieved. While the weight of the glass mass can not be measured directly, changes in the weight of the glass mass can be measured by closely monitoring the position of the hammer 175. Because the volume of the mold cavity (not shown) is a fixed and known amount, the position of the hammer 175 is indicative of the amount of glass present, and in accordance, to the weight of the glass present. If the penetration of the striker 175 is also forward, there is less molten glass present in the mold cavity; if the penetration is less, there is, logically, more glass present.

The hammer 175 (attached to the rod 160) continues to press into the molten glass. When the torsion desired to sufficiently form the hollow globe is reached, the firing pin 175 is held in position for a short period of time, typically measured in my own girth.

The system controller (not shown) then initiates another signal instructing the assembly of the motor 200 to drive in the reverse direction, motivating the inner cylinder 210 to rotate in the opposite direction, moving the striker 175 away from the hollow balloon formed until it is brought to rest. the third position or "percus down" position, which is the position farthest from the mold cavity (not shown). This third position of the striker allows the hollow balloon to be removed from the mold cavity to its next station without obstruction of the striker head. Once the molten glass globe is moved to its next station, it is blown into the desired shape of the blown glass article. Once the hollow balloon is removed from the mold cavity, the hammer 175 is reset to the (intermediate) "load" position. The next molten glass mass is then released into the mold cavity and the process is repeated.

Although the best way contemplated by the inventors to carry out the present invention when the date of the presentation thereof has been shown and described here, it will be apparent to those skilled in the art that appropriate modifications, variations, and equivalences they can be made without departing from the scope of the invention, such scope is limited only by the terms of the following claims and equivalents thereof.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, property is claimed as contained in the following

Claims

RE VINDICACION S

1. An apparatus for the formation of a mass of molten glass in a blown glass article, characterized in that it comprises: a firing pin having a molten glass contact end for contacting a mass of molten glass to form it in a blown glass article; A voter guide screw will be connected to the striker to translate the firing pin along a straight line towards and away from the mass of molten glass to bring the molten glass contact end of the firing pin into and out of contact with the mass of molten glass; Y, The control means for controlling the operation of the voter guide screw will be volatile to control the stroke or rectilinear movement towards and away from the mass of molten glass, the control means comprising a resolution device detecting the position of the hammer to detect the position of the firing pin in all positions along the stroke or movement.

2. The apparatus according to claim 1, characterized in that the control means further comprise means for determining the amount of torsion applied by the servo-driven elector guide screw.

3. The apparatus according to claim 2, characterized in that the means for determining the amount of torsion applied by the elector-to-elector voting guide screw comprises a system controller.

4. The apparatus according to claim 3, characterized in that it also comprises means for controlling the weight of the mass of molten glass that is formed in a hollow balloon or papson.

5. The apparatus according to claim 4, characterized in that the means for controlling the weight of the mass of molten glass comprising the system controller, the system controller using the position of the firing pin that is detected by the resolution device. that detects the position of the hammer.

6. The apparatus according to claim 3, characterized in that the system controller uses the amount of torsion applied by the voter guide screw to be vo-acted to control the molding pressure applied by the glass contact end to the mass of molten glass

7. The apparatus in accordance with the rei indication 1, acterizado because it also comprises the connecting rod, the connecting rod that functionally connects the firing pin to the voter guide screw s vo r a c c t on.

8. The apparatus according to the rei indication 7, characterized in that it also comprises a voltage indicator, the voltage indicator that is connected to the connecting rod, the voltage indicator that measures the amount of molding pressure applied by the glass contact end to the mass of molten glass.

9. The apparatus according to claim 1, characterized in that it further comprises a safety device, the safety device that prevents damage to the glass contact end due to the movement of the end along the rectilinear blow towards the mass of molten glass.

10. A method of forming a mass of molten glass in a blown glass article, the method characterized in that it comprises the s of: the release of a molten glass mass to an open mold cavity; the closure of the mold cavity; the activation of a motor, the motor that is connected to a guide screw, the guide screw that is connected to a striker, by means of which the striker advances in a straight forward direction of a first position until the striker enters in contact with the molten glass mass to a second position; the pressure of the mass of molten glass with the firing pin by which the mass of molten glass is transformed into a hollow globe or parison. the movement of the firing pin in the reverse linear direction directly opposite the forward direction whereby the firing pin breaks contact with the hollow balloon, the stoppage of the striker in a third position; continuously detecting the linear position of the striker along the striker stroke; Y, the extraction of the hollow balloon from the mold cavity.

11. The method according to claim 10, characterized in that it also comprises the step that determines the amount of pressure exerted by the striker on the mass of molten glass.

12. The method according to claim 11, characterized in that it further comprises the step that controls the depth and pressure of the striker on the mass of molten glass using the amount of torsion applied by the motor to the guide screw;

13. The method according to claim 10, characterized in that it comprises the detection step, the linear position of the striker is achieved by the use of a resolution device that detects the position.

14. The method according to claim 10, characterized in that it also comprises the step of preventing damage to the firing pin due to contact with a wall of the mold cavity.

15. The method according to claim 10, characterizes or further comprises the step of controlling the weight of the mass of molten glass released to the cavity of mo 1 d e.

16. The method according to claim 15, characterized in that the step for controlling the weight of the molten glass mass comprises the system controller using the linear position of the firing pin.

17. An apparatus for the formation of a mass of molten glass in a blown glass article, characterized in that it comprises: a mold for the formation of hollow molten glass balloons containing the molten glass mass, the mold for the formation of hollow molten glass balloons having an upper portion and a lower portion; a hollow cartridge, the hollow cartridge that is attached to the lower portion of the mold for the formation of hollow balloons; a housing, the housing that is attached to the cartridge; an engine, the engine mounted inside the housing, an inlet and outlet guide screw, the threaded inlet and outlet guide screw, the inlet and outlet guide screw that is located in the motor, the inlet and outlet guide screw that rotates with respect to the motor and to the lodging; a plurality of rollers, the plurality of rollers embraced with the cord of the inlet and outlet guide screw; a connecting rod, the connecting rod having a leading end and a rearward end, the connecting rod which is partially contained in the housing, the leading end of the connecting rod extending inside the cartridge, the connecting rod which is attached to the plurality of rollers between the the front end of the connecting rod and the rear end of the connecting rod, whereby the rotation of the inlet and outlet guide screw is allowed to be moved in linear motion of the connecting rod; a firing pin, the firing pin connected to the forward end of the rod, the firing pin which is located in the cartridge; Y, means that monitor and control the linear movement of the connecting rod which allows the hammer to be in and out of contact with the mass of molten glass contained in the mold for the formation of the hollow globe.

18. The apparatus according to the indication 17, characterized in that the means that monitor and control include: a resolution device that detects the position of the striker, the resolution device that detects the position of the striker located inside the housing and electrically connected to the motor; a system controller, the system controller electrically connected to the resolution device and the motor, the system controller for the processing of the signals of the resolution device and additionally for the emission of activation signals to the motor.

19. The apparatus according to claim 18, characterized in that the control means further comprise a means for determining the molding pressure exerted by the firing pin.

20. The apparatus according to claim 18, characterized or further comprising means for controlling the weight of the molten glass mass to be transformed into a hollow balloon.

21. The apparatus according to claim 20, characterized in that the means for controlling the weight of the molten glass mass comprises the controller of the system using the detected position of the firing pin.

22. The apparatus according to claim 17, characterized or further comprising means for preventing damage to the striker due to contact between the striker and the mold for the formation of the hollow balloons.

23. The apparatus according to claim 22, characterized in that the means for preventing damage to the striker comprise a programmed safety stop within the system controller. SUMMARY OF THE INVENTION A hammer mechanism for the formation of a blown glass article in a "blow and press the narrow neck" operation using a servo-driven electro guide screw to activate it. A resolution device that detects the position is used to determine the position of the firing pin over the full range of its stroke, and the position information can be used as feedback to control the position of the hammer before making contact with the mass of glass cast in a chamber of the moulder. The penetration depth of the hammer into the molten glass mass is then controlled by the molding pressure, which is a function of the motor torque and screw mechanics. It is possible to control the pressure exerted on the molten glass mass by controlling the torsion applied by the motor. A weight controller of the separate molten glass mass not a mass of molten glass can be determined by closely monitoring penetration of the firing pin into the molten glass mass.