Chamber shrink wrapping machine

Abstract

A chamber shrink wrapping machine having a longitudinal body defining a lower portion of a chamber, a hood with an integral L-sealer transversely hinged to the body to define an upper portion of the chamber when lowered, an air heater to supply heated air to the chamber, a roller conveyor mounted to the body to initially support a product to be wrapped in the chamber longitudinally and transversely closely adjacent the L-sealer during sealing and cutting of heat-shrinkable film around the product when the hood is lowered, wherein the body defines longitudinal and transverse horizontal air ducts in the lower portion of the chamber to direct heated air toward the L-sealer and around the product.

1 . A chamber shrink wrapping machine having a longitudinal body defining a lower portion of a chamber, a hood with an integral L-sealer transversely hinged to the body to define an upper portion of the chamber when lowered, an air heater to supply heated air to the chamber, a roller conveyor mounted to the body to initially support a product to be wrapped in the chamber longitudinally and transversely closely adjacent the L-sealer during sealing and cutting of heat-shrinkable film around the product when the hood is lowered, wherein the body defines longitudinal and transverse horizontal air ducts in the lower portion of the chamber to direct heated air toward the L-sealer and around the product. 
     
     
         2 . A machine according to  claim 1 , wherein the ducts peripherally surround the roller conveyor to allow heated air to flow therearound. 
     
     
         3 . A machine according to  claim 1 , wherein the ducts are formed as horizontal elongate slots. 
     
     
         4 . A chamber shrink wrapping machine having a longitudinal body defining a lower portion of a chamber, a hood with an integral L-sealer transversely hinged to the body to define an upper portion of the chamber when lowered, an air heater to supply heated air to the chamber, a roller conveyor mounted to the body to initially support a product to be wrapped in the chamber longitudinally and transversely closely adjacent the L-sealer during sealing and cutting of heat-shrinkable film around the product when the hood is lowered, wherein the roller conveyor has a plurality of parallel rollers that are transversely skewable and rotatable to subsequently convey the product longitudinally and transversely away from the L-sealer towards the centre of the chamber to allow heated air to circulate around the product to shrink the film thereon, and wherein the plurality of rollers are transversely unskewable and rotatable to finally convey the shrink-wrapped product longitudinally out of the chamber when the hood is raised. 
     
     
         5 . A machine according to  claim 4 , wherein the plurality of rollers are rotatably and transversely skewably supported between two parallel side rails, one of which is fixed to the body and the other of which is longitudinally movable relative thereto to thereby collectively transversely skew the plurality of rollers. 
     
     
         6 . A machine according to  claim 5 , wherein one end of each roller is rotatably and transversely skewably mounted to the fixed side rail by a spring, and the other end of each roller is rotatably and longitudinally slidably mounted in an elliptical seat in the movable side rail. 
     
     
         7 . A chamber shrink wrapping machine having a longitudinal body defining a lower portion of a chamber, a hood with an integral L-sealer transversely hinged to the body to define an upper portion of the chamber when lowered, an air heater to supply heated air to the chamber, a roller conveyor mounted to the body to initially support a product to be wrapped in the chamber longitudinally and transversely closely adjacent the L-sealer during sealing and cutting of heat-shrinkable film around the product when the hood is lowered, and a hood actuator, wherein the hood actuator is arranged to support the weight of the hood whilst it is lowered and then clamp the hood in a closed position. 
     
     
         8 . A machine according to  claim 7 , wherein the hood actuator includes a strut to support the hood, the strut being coupled to a spring loaded over-centre lever arranged to resist movement of the strut, and thereby support the weight of the hood, as the hood is lowered and then draw the strut downwards to clamp the hood closed. 
     
     
         9 . A machine according to  claim 8 , wherein the over-centre lever is loaded by a tension spring fixed to the body of the machine. 
     
     
         10 . A machine according to  claim 7 , wherein the hood actuator is driven to lower the hood, the hood actuator having a one-way clutch that allows the hood to be idly raised. 
     
     
         11 . A machine according to  claim 10 , further including a drive gear fixed to a motor, a free gear fixed to the one way clutch and an engagement device to rotationally fix the fixed gear to the free gear to transmit drive from the motor to lower the hood. 
     
     
         12 . A machine according to  claim 11 , wherein the engagement device is a gear which can be brought into contact with fixed gear and the free gear. 
     
     
         13 . A machine according to  claim 12 , wherein the engagement gear is arranged to be brought into engagement by moving the hood from an initial upright position to a closed position. 
     
     
         14 . A machine according to  claim 10 , wherein the hood actuator is driven by a reduction drive electric motor. 
     
     
         15 . A machine according to  claim 14 , wherein the motor is pivotably mounted on a sprung base so that the motor moves against the action of the springs when the hood is closed to clamp the hood in a closed position. 
     
     
         16 . A machine according to  claim 10 , further including a controller to control the hood actuator. 
     
     
         17 . A machine according to  claim 1 , further including a controller to control the air heater and the roller conveyor.