Abstract:
A work station including hide away doors is presented. The work station includes a frame defining a work area, a front door assembly movable within the frame and a front door assembly track disposed within the frame, the front door assembly movable along the front door assembly track. A drive mechanism is disposed along the frame, the drive mechanism in mechanical communication with the front door assembly, the drive mechanism operable to position the front door assembly in a plurality of positions along the front door assembly track. The front door assembly is capable of being positioned beneath a device within the work area thereby allowing full frontal access to the device within the work area and full overhead access to the device within the work area.

Description:
BACKGROUND 
     Robotic welding stations are used to perform welding operations on devices in an automated manner. Robotic welding stations typically include moveable arc flash shields combined with safety barriers. To load parts into a fixture to be welded, an operator needs exclusive, safe access to the work station interior. When the robot is welding, the operator must be excluded from the work station interior. For safety purposes, the work station requires barriers on the four vertical sides to protect personnel from high intensity visible light, ultraviolet rays, infrared rays, and hot weld spatter associated with arc welding. Barriers on the left and right are typically stationary and in place at all times. The barriers on the operator side (front) and robot side (rear) need to be moveable. When the operator barrier is in place blocking the operator&#39;s access to the work station, the robot side barrier is moved so it no longer blocks the robot access to the work station. When the robot barrier is in place, the operator side barrier is moved so it no longer blocks the operator access to the work station. The operator side barrier also provides a mechanical separation of the robot work space from the operator work space in addition to radiation and spatter protection. 
     SUMMARY 
     Conventional mechanisms, such as those explained above, suffer from a variety of deficiencies. One such deficiency is the front door assembly of the robotic welding station, when positioned to allow operator access, may still provide a barrier as it typically blocks access into the work area by the operator, making it difficult for the operator to load the parts being welded or to remove the part(s) after the welding operation is complete. When the front door assembly is positioned to allow access to the work station by being moved overhead (a garage door type embodiment), overhead access is not possible. Overhead access may be desirable for pieces that require a crane for moving the pieces into and/or out of the work area or to load or remove welding fixtures. 
     Embodiments of the invention significantly overcome such deficiencies and provide mechanisms and techniques that provide moveable doors used for robotic welding stations in that it uses space under the work area for storing of the front door assembly when access to the work area by an operator is required. As such the operator has access inside the work area and can more easily place pieces to be welded and also remove the welded pieces. This arrangement also allows unfettered overhead access for overhead crane insertion and removal of the welded work piece, and it allows for moveable and stationary panels to contain smoke and fumes generated by the welding process. It also uses different panels for the operator and robot barriers, such that the robot door can be closed before the operator door is opened, offering the greatest separation of the operator and the robot for safety purposes. 
     The features of the invention, as explained herein, may be employed in devices such as those manufactured by Dangel Robots and Machinery Incorporated of Bedford, Mass. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
         FIG. 1  comprises a mechanical side view drawing of the welding station including hide away doors in accordance with embodiments of the invention; 
         FIG. 2  comprise a mechanical side view drawing of the door assembly in accordance with embodiment of the invention; and 
         FIG. 3  comprises a view of a robotic welding station incorporating hide away doors in accordance with embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIGS. 1-3 , a robotic welding station  10  having hide-away doors is shown. The robotic welding station includes a frame  12  which defines a work area. The work area typically contains a welding fixture which is used for placing items to be welded in a particular arrangement and may contain a positioner to turn the fixture. 
     Robotic welding station  10  also includes a front door assembly  14 . Front door assembly  14  in this embodiment includes an upper front door panel  24  and a lower front door panel  26 . Preferably, when the front door assembly  14  is in a first position isolating an operator from the work area, a lower section of upper front door panel  24  overlaps an upper section of the lower front door panel  26 . 
     Front door assembly  14  is movable within the work area of frame  12  by way of a drive mechanism  18 , a front door assembly track  16  and a plurality of rollers  28 . In a first position, the front door assembly  14  is in an upright position, such that the front door assembly isolates the robot&#39;s work area from the operator, shielding the operator from arc flash and weld spatter during the welding operation. The front door assembly  14  is movable to a second position under the welding fixture to enhance operator access to the welding fixture. The front door assembly  14  is made of multiple, reinforced door panels, for example an upper door panel  24  and a lower door panel  26  which move down under the welding fixture, wherein the door panels  24  and  26  overlap (nest) and allow the operator to move in close to the welding fixture. The front door assembly  14  provides both arc shielding for welding operations and a mechanical barrier between the operator and the welding robot while allowing the operator more access to the working area without the need to provide a pit in the floor to accept the door panels. This arrangement also allows crane access to the work area and smoke exhaust covering. 
     The front door assembly  14  is attached to the frame  12  and is guided by rollers  28  in a curved front door assembly track  16 . The front door assembly  14  hangs from a drive mechanism  18  which is used to raise and lower the front door assembly  14  within frame  12 . 
     One unique feature of the present invention is that the front door assembly  14  moves down and collapses into a space under the welding fixture, allowing the operator entry into some of the floor space in the work station. By moving down and under the welding fixture, the front door assembly  14  leaves the space above the work station unencumbered by its drive mechanism or barrier storage. The operator entry facilitates access to the welding fixture to remove welded parts and reload the fixture for the next welding cycle. The front door assembly track  16  has a curved section. As the lower door panel  26  of the front door assembly  14  descends it is guided underneath the welding fixture by the curve in the front door assembly track  16  eventually hitting stop  46 . The upper door panel  24  of the front door assembly  14  follows the lower door panel  26  of the front door assembly around the curve and nests over the lower door panel  26 . 
     The front door assembly may further include a spacer block  30  between the upper front door panel  24  and the lower front door panel  26  of the front door assembly  14 . The spacer block  30  maintains the lower part of front door panel  24  in an overlapping relationship with the upper part of lower door panel  26  which prevents the door panels  24  and  26  from separating from each other in the upright position and allows them to nest when the front door assembly  14  is in the lowered position. 
     The front door assembly  14  may include at least one window  44  in the upper front door panel  24 . The window  44  is preferably provided with a protective material which allows the operator to view the welding operation. 
     The workstation may further include a splatter shield  22  disposed within the work area. When the front door assembly  14  is positioned beneath the welding fixture in the work area, the front door assembly  14  is beneath the splatter shield  22 . This protects the front door assembly  14  when the front door assembly  14  is in the nested position. 
     The workstation may also include a rear door assembly  20  and a rear door assembly track  36  disposed within the frame  12 , wherein the rear door assembly  20  is movable along the rear door assembly track  36  by way of rollers  28 . The rear door assembly  20  comprises an upper rear door panel  32  and a lower rear door panel  34 , wherein in one position a bottom portion of the upper rear door panel  32  overlaps an upper portion of the lower rear door panel  34 , while in another position the upper rear door panel  32  nests along side of the lower rear door panel  34 . 
     When front door assembly  14  is in a position preventing frontal access to the work area, the rear door assembly  20  is in a position allowing rear access to the work area. The operator is isolated by the front door assembly  14  being in the upright position, while the rear door assembly  20  is in a lowered position which allows the robotic welder to weld the pieces in the welding fixture. Similarly, when the front door assembly  14  is in a lowered position allowing frontal access to the welding fixture, the rear door assembly  20  is in a position preventing rear access to the welding fixture, thus the operator can enter the work area without fear of the welding operation taking place which would place the operator at risk. 
     This positioning of the front door assembly  14  and the rear door assembly  20  can be synchronized by the drive mechanism  18 , using a single motor  40  to drive both door assemblies  14  and  20  or by the use of a single drive motor for the front door assembly  14  and a second drive motor for the rear door assembly. With a second drive motor the rear door assembly can be closed before the front door assembly is opened, offering the greatest separation of the operator and the welding robot for safety purposes. 
     In a particular embodiment the drive mechanism  18  comprises a first motor  40  coupled to a first flexible connection device  42 . The first flexible connection device  42  is in mechanical communication with the front door assembly. The first flexible connection device  42  is selected from the group consisting of a chain, a cable, a belt or similar type device as would be known by one of ordinary skill in the art. The drive mechanism  18  further comprises a drive shaft coupled to the first motor  40 , and a second flexible connection device coupled to the drive shaft, the second flexible connection device in mechanical communication with the front door assembly  14 . 
     In another particular embodiment the drive mechanism  18  further comprises a second motor coupled to a third and fourth flexible connection devices, the third and fourth flexible connection devices in mechanical communication with the rear door assembly  20 . 
     In a particular example, the work station  10  includes has a main frame  12 , guide tracks  16  and  36 , a drive mechanism  18 , and two roller chains  42 , one at each side of the work station  10 . A drive shaft extends from the motor drive  40  the full width of the work station  10  with a roller chain sprocket on each end, keyed to the drive shaft. The roller chains  42  are connected at each end to the upper door panels  24  and  32  of the front door assembly  14  and the rear door assembly  20 . Each chain  42  passes over a sprocket, in between its connection to the front and rear upper door panels  24  and  32 . When the sprockets are turned clockwise, the upper front door panel  24  is lifted, and the rear door assembly  20  lowered. When the sprockets are turned counterclockwise, the upper front door panel  24  is lowered, and the upper rear door panel  32  is lowered. As the upper door panels  24  and  32  of either the front door assembly  14  or rear door assembly  20  is lifted, they eventually engage the lower door panels  26  and  34  at approximately ½ of full stroke, and lift the lower door panels  26  and  34 . On lowering, the lower door panels  26  and  34  reaches the bottom stop of the guide tracks  16  and  36 , and the upper door panels  24  and  32  continue downward, allowing the doors to nest or telescope together. 
     Having described preferred embodiments of the invention it will now become apparent to those of ordinary skill in the art that other embodiments incorporating these concepts may be used. Accordingly, it is submitted that that the invention should not be limited to the described embodiments but rather should be limited only by the spirit and scope of the appended claims.