Stackable plastic trays

Abstract

In various embodiments of the present invention, trays with mechanical separation features are provided that reduce the adhesion between adjacent trays in a stack of at least partially nested trays or other plastic products. The separation features formed in the trays are strategically located to reduce contact between one tray's bottom surface from the top surface of the tray beneath it. In various embodiments, this is accomplished by employing a plurality of different tray designs, e.g., “A design” and “B design.” The different tray designs have substantially the same size and contour except for the location of the separation features. To prevent adhesion between the trays when stacked, the different tray designs are alternated when stacked (e.g., A design, B design, A design, B design) and the separation features reduce the nesting depth of adjacent trays.

1 . A stack of plastic trays comprising:
 a first tray comprising:
 a substantially planar flange portion extending around the perimeter of the first tray; 
 a first contour portion inward of the flange portion and configured to receive a product; and 
 a plurality of first separation features formed within the first contour portion and having a positive draft angle; and 
   a second tray comprising:
 a substantially planar flange portion extending around the perimeter of the second tray; 
 a second contour portion having substantially the same shape as the first contour portion; and 
 a plurality of second separation features disposed within the second contour portion of the second tray and having a positive draft angle; 
 wherein a location of the plurality of second separation features relative to the second contour portion is different from a location of the plurality of first separation features relative to the first contour portion; and 
   wherein further the first tray is disposed on top of the second tray and each one of the plurality of first separation features engages a portion of the second contour portion of the second tray at a location spaced apart from the second separation features formed in the second contour portion thereby spacing apart a bottom surface of the first contour portion of the first tray from the top surface of the second contour portion of the second tray.   
     
     
         2 . The stack of trays of  claim 1 , wherein the first separation feature is substantially U-shaped. 
     
     
         3 . The stack of trays of  claim 1 , wherein the first separation feature is a notch formed in a wall defined in the contour of the first tray. 
     
     
         4 . The stack of trays of  claim 1 , wherein the first tray is constructed from Polyethylene Terephthalate (PETE), Polyethylene Terephthalate Glycol copolymer (PETG), or Amorphous Polyethylene Terephthalate (APET). 
     
     
         5 . A plurality of stacked trays comprising:
 a first tray having a first contour defining a plurality of walls that at least partially define a pocket to receive a product and a first plurality of separation features formed in at least some of the plurality of walls; and   a second tray having a second contour defining a plurality of walls wherein the plurality of walls defined by the second contour have the same relative position as the plurality of walls defined by the first contour, and the second contour further defining a second plurality of separation features formed in at least some of the plurality of walls of the second tray at different relative locations from the first plurality of separation features defined in the first tray;   wherein further the first tray is disposed on top of and partially nested within the second tray and each one of the plurality of first separation features engages a portion of the plurality of walls defined by the second contour at a location spaced apart from the second plurality of separation features.   
     
     
         6 . The stack of trays of  claim 5 , wherein the first separation feature is substantially U-shaped. 
     
     
         7 . The stack of trays of  claim 5 , wherein the first tray is constructed from Polyethylene Terephthalate (PETE), Polyethylene Terephthalate Glycol copolymer (PETG), or Amorphous Polyethylene Terephthalate (APET). 
     
     
         8 . A method of producing a stack of plastic trays comprising the steps of:
 forming a first tray having a first contour defining a plurality of walls that at least partially define a pocket to receive a product and a first plurality of separation features formed in at least some of the plurality of walls;   forming a second tray having a second contour defining a plurality of walls wherein the plurality of walls defined by the second contour have the same relative position as the plurality of walls defined by the first contour, and the second contour further defining a second plurality of separation features formed in at least some of the plurality of walls of the second tray at different relative locations from the first plurality of separation features defined in the first tray; and   disposing a first tray on top of the second tray wherein each one of the plurality of first separation features engages a portion of the plurality of walls defined by the second contour at a location spaced apart from the second plurality of separation features.   
     
     
         9 . The method of  claim 8  further comprising the step of disposing a second tray on top of the first tray. 
     
     
         10 . A plurality of stacked trays for use in storing medical devices comprising:
 a first tray comprising:
 a substantially planar flange portion extending around the perimeter of the first tray and configured to provide an engagement surface for a lid to seal; 
 a first contour defining a first plurality of walls that at least partially define a pocket to receive a medical device; and 
 a first plurality of separation features formed in at least some of the plurality of walls; and 
   a second tray comprising:
 a substantially planar flange portion extending around the perimeter of the first tray and configured to provide an engagement surface for a lid to seal; and 
 a second contour defining a second plurality of walls wherein the second plurality of walls have the same relative size and position within the second contour as the first plurality of walls defined by the first contour, and the second contour further defining a second plurality of separation features formed in at least some of the plurality of walls of the second tray at different relative locations from the first plurality of separation features defined in the first tray, 
 wherein further the first tray is disposed on top of and partially nested within the second tray and each one of the plurality of first separation features engages a portion of the plurality of walls defined by the second contour at a location spaced apart from the second plurality of separation features, and 
   wherein the engagement of the first separation features of the second contour spaces apart other bottom surfaces of the first contour from the top surfaces of the second contour thereby minimizing adhesion between the first and second trays in the stack of trays.