Tool lift mechanism

Abstract

The present application relates to a lifting apparatus comprising a first member and a second member; a lifting mechanism coupled to said first member adapted to move said first member towards said second member; and a third member coupled to said first member, the third member slideably moveable through said second member when said first member is moved towards said second member. When a predetermined compressive force is applied to said third member, a latching mechanism responds by latching said second member to said third member, such that when a further compressive force is applied to said third member, said first member and lifting mechanism are isolated from said further compressive force.

1 . A lifting apparatus connectable to a tray sealing tool, the lifting apparatus comprising;
 a first member and a second member;   a lifting mechanism coupled to said first member adapted to move said first member towards said second member;   a third member coupled to said first member and slideably moveable through said second member when said first member is moved towards said second member, a distal end of the third member, with respect to the first member, being connectable to a lower tool half of a tray sealing tool such that when said first member is moved towards said second member, the lower tool half is moved towards an upper tool half of the sealing tool,   the lifting apparatus further comprising a latching mechanism, and wherein;   when a predetermined compressive force is applied to said third member, due to the lower tool half contacting the upper tool half, said predetermined compressive force actuates the latching mechanism to latch said second member to said third member, such that when a further compressive force is applied to said third member due to sealing forces in the tray sealing tool, said first member and lifting mechanism are isolated from said further compressive force.   
     
     
         2 . The lifting apparatus of  claim 1 , wherein the latching mechanism comprises a spring mounted between said third member and said first member wherein in use said spring is compressed on application of said compressive force to said third member, and said predetermined compressive force corresponds to a predetermined point in the spring's compression. 
     
     
         3 . The lifting apparatus of  claim 1 , wherein the latching mechanism comprises a latch cam plate having a shaped portion, said latch cam plate fixedly coupled to said first member, and wherein the movement of said first member towards said second member causes said shaped portion to guide a latch so as the latch engages with a protruding potion on said third member. 
     
     
         4 . The lifting apparatus of  claim 1 , wherein said first member is a plate. 
     
     
         5 . The lifting apparatus of  claim 1 , wherein said third member is elongate and coupled to said first member so as to project along the direction of movement of said first member. 
     
     
         6 . The lifting apparatus of  claim 1 , wherein said lifting mechanism is a rotatable lifting screw coupled to the first member in such a manner that rotation of said lifting screw causes movement of said first member in a plane substantially perpendicular to the rotation axis of said lifting screw. 
     
     
         7 . The lifting apparatus of  claim 1 , further comprising one or more third members. 
     
     
         8 . The lifting apparatus of  claim 5 , wherein the lifting screw and the or each third member are substantially parallel. 
     
     
         9 . A tool lift apparatus comprising the lifting apparatus of  claim 1 , and further comprising;
 a lower tool half mounted to the distal end of the or each third member such that, in use, movement of the first member moves said lower tool half towards an upper tool half, and wherein;   said predetermined compressive force is due to said lower tool half and said upper tool half contacting.   
     
     
         10 . The tool lift apparatus of  claim 9 , further comprising a second lifting apparatus, and wherein said lower tool half is mounted to the distal end of the or each third member of the first and second lifting apparatuses, and further wherein the first and second lifting apparatuses are operated in synchrony. 
     
     
         11 . The tool lift apparatus of  claim 9 , further comprising a second lifting apparatus and a second lower tool half mounted to the distal end of the or each third member of said second lifting apparatus, and wherein said first and second lifting apparatuses are operated independently. 
     
     
         12 . The tool lift apparatus of  claim 11 , further comprising a second upper tool half corresponding to the second lower tool half 
     
     
         13 . The tool lift apparatus of  claim 9 , wherein said further compressive force is caused by a process performed when said lower tool half and said upper tool half are in contact. 
     
     
         14 . A traysealing machine comprising the tool lift apparatus of  claim 9 . 
     
     
         15 . The traysealing machine of  claim 14 , wherein the upper tool half contains a heated plate. 
     
     
         16 . The traysealing machine of  claim 14 , wherein the lower tool half is adapted to support one or more trays to be sealed.