Screw element extractor

Abstract

An apparatus for extracting screw elements from a screw shaft comprises a frame, a stationary clamp mounted on the frame and disposable between open and closed positions, a carriage mounted on the frame for motion toward and away from the stationary clamp, a movable clamp mounted on the carriage for motion therewith and disposable between open and closed positions, a first drive coupled to the stationary clamp for opening and closing the stationary clamp, a second drive coupled to the movable clamp for opening and closing the movable clamp, and a third drive coupled to the carriage for causing motion of the carriage toward and away from the stationary clamp, wherein clamping of a downstream screw element by the stationary clamp, clamping of an upstream screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of the downstream screw element held in place by the stationary clamp from the screw shaft. The procedure is repeated until all the remaining screw elements are removed.

What is claimed is:  
     
       1. An apparatus for extracting a plurality of screw elements from a screw shaft, the screw elements being slid over the screw shaft from a downstream end thereof and held in place against a collar provided at an upstream end thereof, the apparatus comprising: 
       a) a frame,  
       b) a stationary clamp mounted on the frame and configured to clamp a downstream screw element, the stationary clamp being movable between an open position permitting reception of a downstream screw element and a closed position clamping the downstream screw element,  
       c) a carriage mounted on the frame for motion toward and away from the stationary clamp,  
       d) a movable clamp mounted on the carriage for motion therewith and configured to clamp an upstream screw element, the movable clamp being movable between an open position permitting reception of an upstream screw element and a closed position clamping the upstream screw element,  
       e) a first drive coupled to the stationary clamp for opening and closing the stationary clamp,  
       f) a second drive coupled to the movable clamp for opening and closing the movable clamp, and  
       g) a third drive coupled to the carriage for causing motion of the carriage toward and away from the stationary clamp, wherein clamping of a downstream screw element by the stationary clamp, clamping of an upstream screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of the downstream screw element from the screw shaft.  
     
     
       2. The apparatus of  claim 1 , wherein the stationary clamp comprises a first pair of jaws slidably mounted on the frame for motion toward and away from each other, and wherein the first drive comprises a first pair of hydraulic motors mounted on the frame and respectively coupled to the first pair of jaws. 
     
     
       3. The apparatus of  claim 2 , wherein the movable clamp comprises a second pair of jaws slidably mounted on the carriage for motion toward and away from each other, and wherein the second drive comprises a second pair of hydraulic motors mounted on the carriage and respectively coupled to the second pair of jaws. 
     
     
       4. The apparatus of  claim 3 , wherein the third drive comprises a third hydraulic motor mounted on the frame and coupled to the carriage. 
     
     
       5. The apparatus of  claim 1 , wherein the first, second and third drives comprise hydraulic motors. 
     
     
       6. The apparatus of  claim 1  further including first, second and third operator controls coupled to the first, second and third drives for controlling the operation of the stationary clamp, the movable clamp and the carriage respectively. 
     
     
       7. The apparatus of  claim 1 , wherein the carriage is mounted on the frame for generally horizontal motion, wherein the stationary and movable clamps are respectively mounted on the frame and the carriage such that a screw shaft supported by the clamps is disposed along a generally horizontal axis. 
     
     
       8. The apparatus of  claim 7  further including downstream and upstream outriggers separate from the frame and arranged adjacent to the downstream and upstream ends of the frame for supporting the downstream and upstream ends of the screw shaft extending beyond the downstream and upstream ends of the frame respectively along the generally horizontal axis. 
     
     
       9. The apparatus of  claim 8 , wherein the first and second outriggers are provided with first and second sets of guide arms, and wherein the frame is provided with generally horizontal, first and second sets of side rails for respectively receiving the first and second sets of guide arms of the first and second outriggers. 
     
     
       10. An apparatus for extracting a plurality of screw elements from a screw shaft, the screw elements being slid over the screw shaft from a downstream end thereof and held in place against a stop provided at an upstream end thereof, the apparatus comprising: 
         a )  a frame,    
         b )  a stationary clamp mounted on the frame and configured to clamp a downstream screw element, the stationary clamp being movable between an open position permitting reception of a downstream screw element and a closed position clamping the downstream screw element,    
         c )  a carriage mounted on the frame for motion toward and away from the stationary clamp,    
         d )  a movable clamp mounted on the carriage for motion therewith and configured to clamp an upstream screw element, the movable clamp being movable between an open position permitting reception of an upstream screw element and a closed position clamping the upstream screw element, and    
         e )  a drive coupled to the carriage for causing motion of the carriage toward and away from the stationary clamp, wherein clamping of a downstream screw element by the stationary clamp, clamping of an upstream screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of the downstream screw element from the screw shaft.   
     
     
       11. An apparatus for extracting a plurality of screw elements from a screw shaft, the screw elements being slid over the screw shaft from a downstream end thereof and held in place against a stop provided at an upstream end thereof, the apparatus comprising: 
         a )  a frame,    
         b )  a stationary clamp mounted on the frame and configured to clamp a downstream screw element, the stationary clamp being movable between an open position permitting reception of a downstream screw element and a closed position clamping the downstream screw element,    
         c )  a carriage mounted on the frame for motion toward and away from the stationary clamp, and    
         d )  a movable clamp mounted on the carriage for motion therewith and configured to clamp an upstream screw element, the movable clamp being movable between an open position permitting reception of an upstream screw element and a closed position clamping the upstream screw element,    
       
         wherein clamping of a downstream screw element by the stationary clamp, clamping of an upstream screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of the downstream screw element from the screw shaft. 
       
     
     
       12. An apparatus for extracting a plurality of screw elements from a screw shaft, the screw elements being slid over the screw shaft from a downstream end thereof and held in place against a stop provided at an upstream end thereof, the apparatus comprising: 
         a )  a frame,    
         b )  a stationary clamp mounted on the frame and configured to clamp an upstream screw element, the stationary clamp being movable between an open position permitting reception of an upstream screw element and a closed position clamping the upstream screw element,    
         c )  a carriage mounted on the frame for motion toward and away from the stationary clamp,    
         d )  a movable clamp mounted on the carriage for motion therewith and configured to clamp a downstream screw element, the movable clamp being movable between an open position permitting reception of a downstream screw element and a closed position clamping the downstream screw element,    
         e )  a first drive coupled to the stationary clamp for opening and closing the stationary clamp,    
         f )  a second drive coupled to the movable clamp for opening and closing the movable clamp, and    
         g )  a third drive coupled to the carriage for causing motion of the carriage toward and away from the stationary clamp, wherein clamping of an upstream screw element by the stationary clamp, clamping of a downstream screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of the downstream screw element from the screw shaft.   
     
     
       13. The apparatus of  claim 12 , wherein the stationary clamp comprises a first pair of jaws slidably mounted on the frame for motion toward and away from each other, and wherein the first drive comprises a first pair of hydraulic motors mounted on the frame and respectively coupled to the first pair of jaws. 
     
     
       14. The apparatus of  claim 12 , wherein the movable clamp comprises a second pair of jaws slidably mounted on the carriage for motion toward and away from each other, and wherein the second drive comprises a second pair of hydraulic motors mounted on the carriage and respectively coupled to the second pair of jaws. 
     
     
       15. The apparatus of  claim 12 , wherein the third drive comprises a third hydraulic motor mounted on the frame and coupled to the carriage. 
     
     
       16. The apparatus of  claim 12 , wherein the first, second and third drives comprise hydraulic motors. 
     
     
       17. The apparatus of  claim 12  further including first, second and third operator controls coupled to the first, second and third drives for controlling the operation of the stationary clamp, the movable clamp and the carriage respectively. 
     
     
       18. The apparatus of  claim 12 , wherein the carriage is mounted on the frame for generally horizontal motion, wherein the stationary and movable clamps are respectively mounted on the frame and the carriage such that a screw shaft supported by the clamps is disposed along a generally horizontal axis. 
     
     
       19. The apparatus of  claim 18  further including downstream and upstream outriggers separate from the frame and arranged adjacent to the downstream and upstream ends of the frame for supporting the downstream and upstream ends of the screw shaft extending beyond the downstream and upstream ends of the frame respectively along the generally horizontal axis. 
     
     
       20. The apparatus of  claim 19 , wherein the first and second outriggers are provided with first and second sets of guide arms, and wherein the frame is provided with generally horizontal, first and second sets of side rails for respectively receiving the first and second sets of guide arms of the first and second outriggers. 
     
     
       21. An apparatus for extracting a plurality of screw elements from a screw shaft, the screw elements being slid over the screw shaft from a downstream end thereof and held in place against a stop provided at an upstream end thereof, the apparatus comprising: 
         a )  a frame,    
         b )  a stationary clamp mounted on the frame and configured to clamp an upstream screw element, the stationary clamp being movable between an open position permitting reception of an upstream screw element and a closed position clamping the upstream screw element,    
         c )  a carriage mounted on the frame for motion toward and away from the stationary clamp,    
         d )  a movable clamp mounted on the carriage for motion therewith and configured to clamp a downstream screw element, the movable clamp being movable between an open position permitting reception of a downstream screw element and a closed position clamping the downstream screw element, and    
         e )  a drive coupled to the carriage for causing motion of the carriage toward and away from the stationary clamp, wherein clamping of an upstream screw element by the stationary clamp, clamping of a downstream screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of the downstream screw element from the screw shaft.   
     
     
       22. An apparatus for extracting a plurality of screw elements from a screw shaft, the screw elements being slid over the screw shaft from a downstream end thereof and held in place against a stop provided at an upstream end thereof, the apparatus comprising: 
         a )  a frame,    
         b )  a stationary clamp mounted on the frame and configured to clamp an upstream screw element, the stationary clamp being movable between an open position permitting reception of an upstream screw element and a closed position clamping the upstream screw element,    
         c )  a carriage mounted on the frame for motion toward and away from the stationary clamp, and    
         d )  a movable clamp mounted on the carriage for motion therewith and configured to clamp a downstream screw element, the movable clamp being movable between an open position permitting reception of a downstream screw element and a closed position clamping the downstream screw element, and    
       
         wherein clamping of an upstream screw element by the stationary clamp, clamping of a downstream screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of the downstream screw element from the screw shaft. 
       
     
     
       23. An apparatus for extracting a plurality of screw elements from a screw shaft comprising: 
         a )  a frame,    
         b )  a stationary clamp mounted on the frame and configured to clamp a first screw element, the stationary clamp being movable between an open position permitting reception of a first screw element and a closed position clamping the first screw element,    
         c )  a carriage mounted on the frame for motion toward and away from the stationary clamp,    
         d )  a movable clamp mounted on the carriage for motion therewith and configured to clamp a second screw element, the movable clamp being movable between an open position permitting reception of a second screw element and a closed position clamping the second screw element,    
         e )  a first drive coupled to the stationary clamp for opening and closing the stationary clamp,    
         f )  a second drive coupled to the movable clamp for opening and closing the movable clamp, and    
         g )  a third drive coupled to the carriage for causing motion of the carriage toward and away from the stationary clamp, wherein clamping of a first screw element by the stationary clamp, clamping of a second screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of one of the first and second screw elements from the screw shaft.   
     
     
       24. An apparatus for extracting a plurality of screw elements from a screw shaft comprising: 
         a )  a frame,    
         b )  a stationary clamp mounted on the frame and configured to clamp a first screw element, the stationary clamp being movable between an open position permitting reception of a first screw element and a closed position clamping the first screw element,    
         c )  a carriage mounted on the frame for motion toward and away from the stationary clamp,    
         d )  a movable clamp mounted on the carriage for motion therewith and configured to clamp a second screw element, the movable clamp being movable between an open position permitting reception of a second screw element and a closed position clamping the second screw element, and    
         e )  a drive coupled to the carriage for causing motion of the carriage toward and away from the stationary clamp, wherein clamping of a first screw element by the stationary clamp, clamping of a second screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of one of the first and second screw elements from the screw shaft.   
     
     
       25. An apparatus for extracting a plurality of screw elements from a screw shaft comprising: 
         a )  a frame,    
         b )  a stationary clamp mounted on the frame and configured to clamp a first screw element, the stationary clamp being movable between an open position permitting reception of a first screw element and a closed position clamping the first screw element,    
         c )  a carriage mounted on the frame for motion toward and away from the stationary clamp, and    
         d )  a movable clamp mounted on the carriage for motion therewith and configured to clamp a second screw element, the movable clamp being movable between an open position permitting reception of a second screw element and a closed position clamping the second screw element,    
       
         wherein clamping of a first screw element by the stationary clamp, clamping of a second screw element by the movable clamp and one or more strokes of the carriage away from the stationary clamp result in removal of one of the first and second screw elements from the screw shaft.