Abstract:
A case erector is configured to open folded cases. In one example, the case erector includes a planar bearing surface. A semi-circular channel is defined in the planar bearing surface about a center point. Additionally, a notch is located so that the planar bearing surface does not extend to the center point of the semi-circular channel. A plate is in contact with the planar bearing surface. The plate has at least one flange sized for travel within the semi-circular channel so that the plate rotates against the planar bearing surface in a circular manner about the center point. A notch is defined in the plate so that the plate does not extend to the center point of the semi-circular channel. An arm is connected to the plate so that the plate and the arm rotate together with respect to the planar bearing surface. In operation, a folded edge of a folded case is positioned at the center point. One or two arms, moved by plates rotating on bearing surfaces, attach to and open the folded case.

Description:
RELATED APPLICATIONS 
   This patent application claims priority to U.S. Provisional Patent Application Ser. No. 60/977,317, having title “Case Erector”, filed on 3 Oct. 2007 in the United States, commonly assigned herewith, and hereby incorporated by reference. 

   BACKGROUND 
   Cases (e.g. cardboard boxes) are commonly sold in a folded flat (i.e. a knocked down) configuration. A case erector is a machine that assembles cases from the folded flat configuration into a three-dimensional form, typically having bottom box flaps taped or glued shut. 
   Known case erectors have two arms, typically configured with suction or vacuum cups, which grasp two adjacent sides of the box, respectively. Each arm then moves through 45 degrees thereby opening the box. In an application with a single arm, the single arm may move through 90 degrees. In either application, such arms are supported by bearing surfaces, which allow the pivotal rotation. 
   It is desirable to locate the fold between the two adjacent sides of the box that are grabbed by the two arms co-linearly with an axis about which the two arms pivot. This results in a design challenge, in that it is desirable to locate a (usually) vertical shaft (about which the arms pivot) in the same location that it is desirable to locate the fold in the box. 
   Two solutions are common. In a first solution, the fold in the box (between the two adjacent sides that are grasped by the arms) can be located “near” (but not exactly collinear with) the shaft about which the two arms pivot. This will cause the box to skew as it is opened. The skew occurs because the fold between the two adjacent sides of the box and the two arms do not pivot about the same virtual center point. This skew is generally unacceptable, and therefore a second solution is common. 
   In the second solution, the shaft about which the two arms pivot is located above (or below) the box, so that if the shaft were extended in one&#39;s imagination, the shaft would be co-linear with the fold between adjacent sides of the box. Since the shaft is located above the box as the box is moved into position to be opened, the arms must extend laterally outward from the shaft and also extend down to the box, so that vacuum cups carried by the arms may contact the adjacent sides of the box. This makes the overall device heavier and more complex, and requires arms having increased strength due to their length and other factors. While this solution allows the arms to be kept parallel to the box sides, (the arms reach down from above or up from below) the structure required to support the erecting arms must be more robust which will increase cost, complexity and overall size of the mechanism. 
   SUMMARY 
   A case erector is configured to open folded cases. In one example, the case erector provides first and second arms, each having at least one suction or vacuum device. A planar bearing surface allows at least one of the arms to move between an open position and a closed position. The planar surface defines a semi-circular channel about a virtual center point. In operation, a fold between two adjacent sides of the case is moved into a virtual line passing through the virtual center point while the arms are in the open position, thereby allowing space for the case to enter. The arms are then moved to the closed position, wherein the first and second arms grasp the two adjacent sides, respectively, of the folded flat case. The case is then opened by moving the arms into the open position while the arms maintain their grasp of the case. Movement to the open position is performed by moving each arm through 45 degrees or one arm through 90 degrees. Movement of the arms in a rotary manner about the virtual line results from rotation of a plate supporting each arm, wherein each plate moves against the planar bearing surface and wherein the plate has one or more attached flanges moving through the semi-circular channel defined in the planar bearing surface. 
   This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended for use as an aid in determining the scope of the claimed subject matter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items. 
       FIG. 1  shows an isometric view of an example case erector, with the arms in the open position. 
       FIG. 2  shows an isometric view of the case erector of  FIG. 1 , with the arms in the closed position. 
       FIG. 3  shows an orthographic top (plan) view of an example case erector, with the arms in the open position. 
       FIG. 3A  shows an isometric view similar to that of  FIG. 3 . 
       FIG. 4  shows an orthographic top (plan) view of the case erector of  FIG. 3 , with the arms in the closed position and a case in the unassembled position. 
       FIG. 5  shows an orthographic top (plan) view of the case erector of  FIG. 3 , with the arms in the open position and a case in the erected or open position. 
       FIG. 6  shows an orthographic side view of an example case erector, with the arms in the open position. 
       FIG. 7  shows an orthographic top view of an example case erector, with the arms in the open position. 
       FIG. 8  shows a section view of the bearing assembly of  FIG. 7 . 
       FIG. 9  shows a further example of a bearing surface that could be used in an embodiment of the case erector. 
   

   DETAILED DESCRIPTION 
   Overview 
   The following discussion is directed to systems and methods that erect cases (e.g. systems that open cardboard boxes from a disassembled state to an assembled state). In one example, a case erector configured to open folded cases provides first and second arms, each having at least one attachment device, such as a suction or vacuum device or clamp assembly. A planar bearing surface allows at least one of the arms to move between an open position (wherein a folded flat case is received) and a closed position (wherein the folded case is grabbed) and then moved to the open position (wherein the case is opened into a 3-D box-like shape with open or no flaps on the top and flaps on bottom). In a preferred configuration, each of the two arms moves through approximately 45 degrees. The planar bearing surface defines a semi-circular channel about a virtual center point. In operation, a fold between two adjacent sides of the case is moved into coincidence with a virtual line passing through the virtual center point. Once the fold of the case is in position in the virtual line passing through the virtual center point, the first and second arms move from the open position to the closed position to grasp the two adjacent sides, respectively. Each arm is supported by a plate that moves against a planar bearing surface, wherein the plate is held in place by at least one flange that moves within a semi-circular channel defined within the planar bearing surface. Thus, the plate supporting each arm moves (rotates) in a circular manner, about the virtual center point. The case is then opened as both arms move through 45 degrees from the closed position to the open position, thereby opening the case. Because the fold (i.e. the corner) of the case was located in a virtual line passing through the virtual center point of the semi-circular channel, the arms will remain parallel to the two adjacent box sides, as the box opens in a square or non-skewed manner. 
   Examples of Case Erectors 
     FIG. 1  shows an isometric view of an example case erector  100 , with the arms in the open position. In particular, first and second arms  102 ,  104  are separated by 90 degrees in the open position, which allows a case to be moved into position between the arms. The 90 degrees between the arms  102 ,  104  also holds adjacent sides of a box in the appropriate configuration when the box is opened. Each arm  102 ,  104  may include one or more attachment devices, such as suction cups  106 , which are typically powered by a vacuum source. Alternatively, a clamping assembly could be used. 
   The arm  102  is supported by a plate  108  that rotates against a planar bearing surface  110 . (The arm  104  is supported by a similar plate, which is on the other side of base  118  and therefore unseen in  FIG. 1 .) While a plastic or UHMW material is used for the bearing surface  110  in the example of  FIG. 1 , metal or alternative material may also be used. A flange  112  attached to the plate  108  moves within a channel  114  defined in the bearing surface  110 . Thus, rotation of the plate  108  is in a circular direction, due to the movement of the flange within the semi-circular channel  114 . Accordingly, the circular rotation of the plate  108  moves the attached arm  102  in a circular direction. The channel  114  is semi-circular, to allow rotation of the plate  108  between an open position wherein the arm  102  allows a folded case to enter, a closed position wherein the folded case is grasped by the arm  102 , and back to the open position wherein the case is opened. Thus, the plate  108  and attached arm  102  moves over approximately 45 degrees, and the bearing surface  110  remains fixed. Similarly, the second arm  104  moves according to rotation of a second plate over 45 degrees, wherein the rotation is through a second semi-circular channel defined a second bearing surface better seen in  FIG. 6 . 
   The channel  114  defined in the bearing surface  110  is typically semi-circular in shape, and may extend over approximately 270 degrees of a circle, depending on the application. The center of the circle (about which the semi-circular channel  114  is defined) can be thought of as a “virtual center” since no component is positioned at that location. In fact, the bearing surface  114  defines a notch (best seen as  308  in  FIG. 3 ), which allows a fold between two sides of a case (i.e. a “corner” of the case) to be located at the center or “virtual center” of the semi-circular channel  114 . 
   The arms  102 ,  104  are moved by actuators  116  and  117 , which may operate using a compressed air power source. Alternative technology, such as motor and/or gears may be substituted. In one example, the actuators  116 ,  117  are attached to plates  108  and  604  (see  FIG. 6 ); alternatively, the actuators are attached to the arms  102 ,  104 . In either case, the actuators provide the force to move plates  108  and  604  against the fixed-location bearing surfaces  110  and  602  (see  FIG. 6 ), whereby the plate and attached arm rotate about the center point. 
   Both arms  102 ,  104 , supporting plates and bearing surfaces, actuators  116 ,  117  and other components are supported by a base  118  and two bearings  120 . The bearings  120  allows the arm assembly to move along a shaft  122 . Typically, the case, once opened, is moved along the shaft  122  into a plow, which aids in closing and sealing the bottom flaps of the case. A hose assembly  124  has a linkage design, which supports the hoses as the arm and bearing surface assembly moves along the shaft  122 . 
   In the example of  FIG. 1 , the attachment devices  106  (e.g. vacuum cups) are attached to an adjustment plate  126  defining a plurality of adjustment slots  128 . A bracket  130  holding the attachment device  106  can therefore be positioned in any desired location. 
     FIG. 2  shows an isometric view of the case erector  100 , with the arms  102 ,  104  in the closed position. Note that in the closed position, the suction cups  106  of the second arm  104  are separated from the suction cups of the first arm  102  by only the thickness of the disassembled case. Thus,  FIG. 2  shows the arms  102 ,  104  in the “closed” position wherein they are grasping the still closed case. The case is not shown in this view, for clarity of illustration. Once the two adjacent sides of the case are grasped by the arms  102 ,  104 , the arms are again rotated into the “open” configuration seen in  FIG. 1 . 
   A comparison of  FIGS. 1 and 2  shows that the plate  108  has rotated counter-clockwise by 45 degrees. This has caused the attached arm  102  to rotate 45 degrees. The plate  108  was constrained in its rotation by the flange  112 , attached to the plate  108 , which travels within the channel  114  of the bearing surface  110 . The arm  104  has similarly rotated 45 degrees. However, the plate to which it is attached is located under supporting plate  118 , and is therefore not shown. Note that the plate  108  somewhat resembles a piece of pizza with a portion near the center point removed. Removal of this portion near the center point results in an open area that allows the fold of the case to move into a collinear position with a virtual center line passing through the virtual center point, wherein the virtual center point is the center of the semi-circle formed by the channel  114 . 
     FIG. 3  shows an orthographic top (plan) view of an example case erector  100 , with the arms  102 ,  104  in the open position. In this view, an unopened case  300  is shown. The fold  302  between a first side  304  and a second side  306  of the case  300  is located at the center or virtual center  308  of the semi-circle defined by the channel  114  defined in the bearing surface  110  (better seen in  FIG. 1 ). Thus, the center  308  of the semi-circular channel  114  (see  FIG. 1 ) is located (referring now to  FIG. 3A ) in a notch  310  defined in the bearing surface  110 . Similarly, a notch  312  is defined in the plate  108 , which prevents the plate from extending to the center  308 . And further, the supporting plate  118  had defined in it a similar notch  314 . Thus, the notch  310  in the bearing surface  110 , the notch  312  in the plate  108  and the notch  314  in the supporting plate  118  allow the fold  302  of the case  300  to be located at the center point  308 . 
   Note that in the view of  FIG. 3 , the actuator  116  has extended to rotate the plate  108  supporting arm  102  into its most clockwise position. The plate supporting the arm  104  (and a bearing surface within which is defined a channel that controls movement of the plate) will be better seen in later figures, and is located below the plate  118 . 
     FIG. 4  shows an orthographic top (plan) view of the case erector  100 , with the arms  102 ,  104  in the closed position. Two adjacent sides of the box  300  have been grasped by the arms. The actuator  116  has retracted, and the plate  108  supporting the arm  102  has rotated counter clockwise in response. Note that when the arms  102 ,  104  open again to the positions seen in  FIG. 3 , the box  300  will be opened, with the two adjacent sides  304 ,  306  still attached to arms  102 ,  104 , respectively. 
     FIG. 5  shows an orthographic top (plan) view of the case erector  100 , with the arms  102 ,  104  in the open position and the case fully opened. Two adjacent sides  304 ,  306  of the box  300  have been moved to separate them by 90 degrees, thereby opening the case (box). The actuator  116  has extended, and the plate  108  supporting the arm  102  has rotated clockwise in response. Note that when the arms  102 ,  104  open again to the positions seen in  FIG. 3 , the box  300  will be opened, with the two adjacent sides  304 ,  306  still attached to arms  102 ,  104 , respectively. 
     FIG. 6  shows an orthographic side view of an example case erector  100 , with the arms  102 ,  104  in the open position. Note that if an opened box were held by the arms, then the assembly  100  would be ready to move to the right along the bearings  120  and supported by the shaft  122 . The hose assembly  124  would extend as the arm assembly moved along the shaft  122 . 
     FIG. 6  shows the plate  108  supporting the arm  102  and the bearing surface  110  seen in perspective in  FIG. 1 . Below the bearing surface is a flange or base  118 . Below the base  118  is a second bearing surface  602  against which rotates a plate  604 . The second bearing surface  602  and plate  604  are associated with the second arm  104 . The second bearing surface  602  defines a semi-circular channel through which a flange attached to the plate  604  moves. Thus, the bearing surface  602  is stationary, but an actuator  117  moves the plate  604  through approximately 45 degrees in either direction, thereby moving the arm  104  through 45 degrees. The semi-circular channel in the bearing surface  602  has a center point that is along a vertical line that also includes the center point of the channel  114  defined in the bearing surface  110 . Thus, both arms  102 ,  104  pivot about the same virtual center point, and the fold between the two adjacent sides of a case to be opened is positioned along a vertical line through those center points. 
     FIGS. 7 and 8  show orthographic views of an example case erector. 
     FIG. 9  shows a further example of a bearing surface that could be used in an embodiment of the case erector. Thus, the plastic surface  110  having channel  114  could be replaced by a constant radius rail, or similar, as shown. 
   CONCLUSION 
   Although aspects of this disclosure include language specifically describing structural and/or methodological features of preferred embodiments, it is to be understood that the appended claims are not limited to the specific features or acts described. Rather, the specific features and acts are disclosed only as exemplary implementations, and are representative of more general concepts.