Abstract:
An automated removal and insertion machine for mold drawers operable with a molding machine is described. The machine includes a frame, a plurality of actuators mounted within the frame, a plurality of encoders, a plurality of electromagnetic effectors, and a controller. The actuators are operable in a substantially horizontal direction for removal and insertion of molds with respect to the molding machine, and movable within the frame in a substantially vertical direction. At least one of the encoders is operably attached to each of the actuators for providing data indicative of a position of the respective said actuators. At least one electromagnetic effector is attached to a terminal end of each of the actuators for engagement with a respective mold. The controller is operable to control movement of the actuators in the substantially horizontal direction and further operable for controlling power applied to the electromagnetic effectors.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/122,008, filed Dec. 12, 2008, entitled “Mold Drawer Puller”, the contents of which are incorporated by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The field of the invention relates generally to molds, and more specifically, to the manipulation of mold drawers with respect to molding mechanisms including apparatus and methods for automating handling of mold drawers. 
         [0003]    Molding mechanisms are utilized to produce molded parts which are not readily formed by injection molding processes. Material to be molded is first placed within a cavity in a mold drawer. The mold drawer is then placed within the mold mechanism (i.e., an electro-mechanical system capable of applying heat and pressure to the mold drawers) and the mechanism is closed and pressure and heat are applied to the mold drawer, thus forcing the material to fill the entire cavity within the mold drawer. Heat and pressure are maintained within the mold drawer until the material has sufficiently cured and filled the cavity. The mold drawers are then removed from the mold and the cured material is removed therefrom. In many molding mechanisms, the mold drawers must be manually placed within the mold mechanism and removed therefrom by an operator of the mechanism. 
         [0004]    The production of large, molded parts in molding operations requires the use of correspondingly large mold drawers. Consequently, the mold drawers are heavy (i.e., weighing as much as 4,000 lbs.) and cumbersome, thus rendering their manipulation by operators difficult. While the mold drawers may be movable on tracks or other wheeled mechanisms, the operator is still required to impart the force necessary to move the mold drawers along the tracks. 
         [0005]    The ergonomics of pushing and pulling large, heavy mold drawers by the operators subject the operators to repetitive-type injuries because of the force and awkwardness of the motions required to manipulate the mold drawers. Further, once the mold drawers begin moving on the tracks, the operator lacks the strength to sufficiently control or stop their movement. The uncontrolled movement of the mold drawers on the tracked or wheeled mechanisms raises safety concerns as well. Operators often pull the mold drawers quickly towards themselves and then release the mold drawers, thus permitting the mold drawers to freewheel into stops positioned at a terminal end of the tracks. Over time, the stops may fail and result in a catastrophic failure with the mold drawers coming off of their tracks and falling, often resulting in damage to equipment and injury of persons nearby. 
         [0006]    Accordingly, a system is needed that requires only minimal modification of existing molding mechanisms, while significantly reducing or eliminating the amount of operator intervention required to place mold drawers within the molding machine and remove them from same. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0007]    Certain exemplary aspects of the invention are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below. 
         [0008]    In one aspect, an automated removal and insertion machine for mold drawers operable with a molding machine is provided. The machine includes a frame, a plurality of actuators mounted within the frame that are operable in a substantially horizontal direction for removal and insertion of molds with respect to the molding machine, the actuators being movable within the frame in a substantially vertical direction. The apparatus further includes a plurality of encoders, at least one encoder operably attached to each of the actuators for providing data indicative of a position of the respective actuators, a plurality of electromagnetic effectors, each electromagnetic effector is attached to a terminal end of a respective one of the actuators for engagement with a respective mold, and a controller operable to control movement of the actuators in the substantially horizontal direction. The controller is further operable for controlling power applied to the electromagnetic effectors, the controlled movement of the actuators and application of power to the electromagnetic effectors is operable for insertion and removal of at least one mold drawer with respect to the molding machine. 
         [0009]    In another aspect, a method for automated movement of a mold drawer with respect to a molding machine is provided. The method includes positioning a drawer engaging device mounted within a frame in the vertical direction for substantial horizontal alignment with the mold drawer, extending an arm associated with the drawer engaging device in the substantial horizontal direction a first distance such that a terminal end of the arm is proximate the mold drawer, activating an electromagnetic effector attached to the terminal end of the arm to initiate and maintain a magnetic engagement between the terminal end and the mold drawer, retracting the arm a second distance, the second distance sufficient for removing the mold drawer from the molding machine, extending the arm the second distance to insert the mold drawer into the molding machine, and deactivating the electromagnetic effector. 
         [0010]    In still another aspect, a system for positioning a mold with respect to a molding machine is provided. The system includes a frame having at least a bottom side and a vertical axis, an adjustment mechanism positioned within the frame that is substantially parallel to the vertical axis, and a plurality of hydraulic cylinders each having a terminal end, wherein the plurality of hydraulic cylinders are individually engaged with the adjustment mechanism within the frame in a substantially perpendicular orientation with respect thereto. The adjustment mechanism permits independent vertical positioning of each of the plurality of hydraulic cylinders with respect to the frame. The system also includes a corresponding plurality of electromagnetic effectors affixed to the terminal ends of each of the plurality of hydraulic cylinders. The plurality of corresponding electromagnetic effectors and the plurality of hydraulic cylinders are operable to independently engage one or more molds to cause lateral movement of the molds. The system further includes a plurality of anti-rotation rods having a distal end and a terminal end and positioned substantially parallel to each of the plurality of hydraulic cylinders. The terminal end of each of the plurality of anti-rotation rods is affixed to a portion of the electromagnetic effectors affixed to the terminal end of the hydraulic cylinder, wherein the distal end is connected to a portion of the frame. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of a mold drawer puller. 
           [0012]      FIG. 2  is a perspective view of the mold drawer puller and a molding mechanism. 
           [0013]      FIG. 3  is an enlarged perspective view of a portion of the mold drawer puller including a connection mechanism. 
           [0014]      FIG. 4  is a side view of a portion of the mold drawer puller including an adjustment mechanism. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    A mold drawer puller is depicted generally at  100  in  FIG. 1 . The mold drawer puller  100  includes a frame  102  having a bottom side and a vertical axis V. Included within the frame  102  are hydraulic cylinders  106 , which are supported by a front bar  108 . The front bar  108  has a cam and roller assembly  110  attached thereto that permit vertical translational movement of the hydraulic cylinders  106  along the vertical axis V and with respect to the front bar  108 . The cam and roller assembly  110  prevents any other movements by the hydraulic cylinders  106 . A back bar (not shown) may support the hydraulic cylinders  106  as well, according to some embodiments. 
         [0016]    As utilized herein, a hydraulic cylinder refers to a device that includes a cylinder barrel, in which a piston connected to a piston rod moves back and forth. The cylinder barrel is closed on each end by the cylinder bottom and by the cylinder head where the piston rod comes out of the cylinder. The hydraulic pressure acts on the piston to do linear work and motion, moving the piston rod into and out of the cylinder barrel. 
         [0017]    According to one embodiment, four hydraulic cylinders  106  and their associated piston rods  118  are provided, although any number of hydraulic cylinders  106  may be utilized, depending on the molding machine with which the mold drawer puller  100  is matched. In some embodiments, multiple mold drawers  112  (as seen in  FIG. 2 ) may be used within a molding mechanism  114 , with each mold drawer  112  having at least one corresponding hydraulic cylinder  106  and piston rod  118  responsible for its placement within the molding mechanism and removal therefrom. The hydraulic cylinders  106 , piston rods  118 , and the components associated therewith are sized based on the amount of force required to remove or pull the mold drawers  112  from the molding mechanism  114  and push them back into position therein. For larger mold drawers  113  (also shown in  FIG. 2 ), multiple hydraulic cylinders  106  may be used in tandem, while for smaller mold drawers  112  a single hydraulic cylinder  106  and piston rod  118  may be used. 
         [0018]    As shown in  FIG. 2 , in operation the mold drawer puller  100  is positioned generally adjacent to the molding mechanism  114 . The mold drawer puller  100  is therefore operable to either pull the mold drawers  112 ,  113  to remove mold drawers from the molding mechanism  114 , as well push the mold drawers  112 ,  113  into the molding mechanism. According to some embodiments, the molding mechanism  114  may be a compression molding mechanism. However, according to other embodiments it may be a different type of molding mechanism, such as an injection molding mechanism. 
         [0019]    While specific mention is made herein to hydraulic actuation systems, other systems are contemplated as well. For example, pneumatic cylinders which operate piston rods or linear actuators and their associated extension devices may used instead of, or in conjunction therewith, hydraulic cylinders  106  to pull or remove the mold drawers  112  from the molding mechanism  114 . Hydraulic cylinders, pneumatic cylinders and linear actuators may be collectively referred to herein as actuators. 
         [0020]    Referring again to  FIG. 1 , a safety cage  144  is provided around the exterior of the mold drawer puller  100 , according to some embodiments. The safety cage  144  prevents the operator or any other individual from coming into contact with the components of the mold drawer puller  100 . The safety cage  144  may be removable to permit access to the components of the mold drawer puller  100 . 
         [0021]    Referring to both  FIGS. 1 and 4 , electromagnetic effectors  116  are attached to a terminal end of piston rods  118  extending from the hydraulic cylinders  106 . The electromagnetic effectors  116  assist in the engagement of mold drawers  112 ,  113  by the mold drawer puller  100 . Upon the application of electrical current to the electromagnetic effectors  116 , the effectors  116  become magnetized. As most, if not all, mold drawers  112 ,  113  are constructed using ferrous metals, the electromagnetic effectors  116  provide a releasable attachment mechanism between the mold drawer puller  100  and the mold drawers  112 ,  113 . According to one embodiment, when removing mold drawers  112 ,  113  from within the molding mechanism  114 , the electromagnetic effectors  116  are magnetized and come into contact with the mold drawers  112 ,  113 . The hydraulic cylinders  106  are then retracted, and the mold drawer  112 ,  113  is pulled out of the molding mechanism  114 , as the mold drawer  112 ,  113  is held adjacent to electromagnetic effectors  116  by magnetic forces. The same principle applies for placing mold drawers  112 ,  113  within the molding mechanism  114 . In alternative embodiments, other types of effectors may be utilized to manipulate the mold drawers  112 ,  113  such as mating couplings, with one portion of the coupling affixed to the mold drawers  112 ,  113  and the other portion affixed to the terminal end of the rods  118  extending from the hydraulic cylinders  106 . 
         [0022]    Now referring to  FIG. 3 , electrical current is supplied to the electromagnetic effectors  116  by a retractile cord  120  coiled around a support. The retractile cord  120  is thus prevented from coming into contact with any of the components of the mold drawer puller  100  or the mold drawers  112 . 
         [0023]    Anti-rotation rods  122  are provided to prevent the rod  118  extending from the hydraulic cylinders  106  (and the electromagnetic effectors  116  attached thereto) from rotating. At least one anti-rotation rod  122  is provided for each hydraulic cylinder  106 . A terminal end of the anti-rotation rod  122  is attached to the electromagnetic effecter  116 , while the opposite end of the anti-rotation rod  122  or a portion thereof is attached to the frame  102 . The position of the electromagnetic effectors  116  and hence the rods  118  extending from the hydraulic cylinders  106  to which they are attached is determined by a string encoder  124  attached to the anti-rotation rods  122 . 
         [0024]    The rods  118  extending from the hydraulic cylinders  106  are retracted or extended based by closing proportional valves (not show) controlling the flow of hydraulic fluid to the hydraulic cylinders. The proportional valves may be controlled by an electro-mechanical control mechanism. The electrical-mechanical control mechanism may receive an input from the operator (i.e., press of a switch on a control pendant  126  shown in  FIG. 1 ) indicating the operator&#39;s desire to move extend or retract the rods  118  to a predefined position. According to some embodiments, the operator may be required to use both hands to initiate movement of the hydraulic cylinders  106 . This may be accomplished by spaced-apart controls that must synchronously actuated by the operator. 
         [0025]    The electro-mechanical system then actuates the proportional valves to retract or extend the rods  118  to the desired position. The position of the rods  118  is determined by the string-encoders  124 , and a feedback control system within the electro-mechanical system permits the accurate positioning of the rods with respect to the desired position. According to some embodiments, the hydraulic cylinders  106  may be actuated independently of each other, thus permitting the removal of specific mold drawers  112 ,  113  within the molding mechanism  114 . 
         [0026]    While a substantial portion of the weight of the mold drawer puller  100  is supported by wheels  134  or casters attached to the frame  102 , a connection mechanism  136  is provided according to one embodiment. The frame of the mold drawer puller  100  is attached to an underlying structure (i.e., a floor) by the connection mechanism  136  (as best seen in  FIG. 3 ). The connection mechanism  136  utilizes a floor plate  138  attached to the underlying structure. A track  140  is formed in the floor plate  138  or suitably attached thereto. Cam rollers  142  are attached to a structure on the bottom side  104  of the frame  102  and travel within the track  140 . The track  140  suitably constrains the cam rollers  142  and permits the mold drawer puller  100  to travel transversely along the track, but otherwise restrain it from moving longitudinally or laterally. Accordingly, the connection mechanism  136  significantly reduces or eliminates the risk of the mold drawer puller  100  from tipping over, while ensuring its proper location. 
         [0027]    Furthermore, corresponding sets of holes (not shown) may be formed in the bottom side  104  of the frame  102  and the floor plate  138 . A rod or other rigid mechanism may be inserted through the corresponding sets of holes to securely lock the mold drawer puller  100  in position and prevent it from travelling transversely along the track  140 . The rod may then be removed to allow the mold drawer puller  100  to be quickly removed to permit access to the molding mechanism  114 . According to some embodiments, an automatic locking mechanism may be provided which inserts the rod through the corresponding holes without requiring the operator to do so. The insertion of the rod through the corresponding sets of holes formed in the bottom side  104  of the frame  102  stabilizes the mold drawer puller  100  in place, and thus provides a reaction force to counter force exerted by the actuation of the hydraulic cylinders  106 . 
         [0028]    The vertical position of the hydraulic cylinders  106  within the frame  102  may be adjusted by an adjustment mechanism  128 , as best seen in  FIG. 4 . According to one embodiment, the adjustment mechanism  128  is comprised of a vertical screw  130 , and a nut  132  corresponding to each hydraulic cylinder  106 . The hydraulic cylinder  106  is rotatably engaged with its corresponding nut  132  or is placed atop the nut. Accordingly, the nut  132  may be rotated to displace it along the vertical screw  130 . As the hydraulic cylinder  106  is attached to the nut  132  or resting thereon, any translation of the nut  132  necessarily results in corresponding translation of the hydraulic cylinder. In the embodiment depicted in  FIG. 4 , the vertical screw  130  is a rod with threads displaced thereon, while the nut  132  is an oversized wing nut which is sized to be easily rotated by an operator of the mold drawer puller  100 . While the nut  132  and vertical screw  130  solution is easy to implement, embodiments which use hydraulics or pneumatics to move cylinders  106  up and down are also contemplated. 
         [0029]    During setup of the mold drawer puller  100 , the hydraulic cylinders  106  are vertically positioned with the aid of the adjustment mechanism  128  in order for the electromagnetic effectors  116  to be properly aligned with the mold drawers  112 . The horizontal extension required of the hydraulic cylinders  106  and the rods  118  extending therefrom to extract or place the mold drawers  112  within the molding mechanism  114  is programmed into the electro-mechanical system by extending the hydraulic cylinders until each of them has contacted the individual mold drawers. The operator then presses a button on the control pendant  126  connected to the electro-mechanical system which records the current location of the hydraulic cylinders  106  (and hence the locations of the mold drawers  112 ) as provided by the string-encoders  124 . When the operator subsequently commands the hydraulic cylinders  106  to retract, they will automatically stop at this location, turn on the electromagnetic effectors  116 , and retract back out of the molding mechanism  114 . 
         [0030]    Proportional controls and extension feedback is used to limit the acceleration of the hydraulic cylinders  106 . Without a soft stop of the hydraulic cylinders  106 , the momentum of the mold drawers  112  may cause them to be detached from the electromagnetic effectors  116  and enable a freewheeling condition. A programmable logic controller (PLC) included within the electro-mechanical system takes feedback from the string-encoder  124  and feeds it into a proportional control algorithm that calculates how far to open the proportional valves to maintain safe speeds and accelerations. 
         [0031]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 
         [0032]    While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the figures and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims. One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
         [0033]    When introducing elements of various embodiments of the present invention, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, the use of “top”, “bottom”, “above”, “below” and variations of these terms is made for convenience, but does not require any particular orientation of the components.