Hydraulic-mechanical clamping device

Abstract

A self-locking hydraulic clamping device includes a hydraulic piston which is notched on one side to form a compound camming surface which drivingly engages a spring-loaded clamping pin moving in a bore normal to the bore in which the hydraulic piston moves, the latter bore preferably extending parallel to the side of the workpiece being clamped.

What is claimed is: 
     
       1. A compact self-locking hydraulic clamping device comprising a body, a primary bore extending from an end of said body, a secondary bore intersecting said primary bore intermediately and extending normally to said primary bore from said primary bore to a face of said body, a piston slidably received in said primary bore and including a shank passing back and forth past the intersection between the primary and secondary bores, piston chamber defining means associated with said primary bore, compound camming surface means extending non-reentrantly across one side of said piston shank and positioned to pass back and forth over said secondary bore during said back and forth movement of said piston to present different stages of said compound camming surface means, a clamping pin in said secondary bore, said pin being biased toward said camming surface means by a spring located in said secondary bore, a key preventing rotation of said clamping pin with respect to said body, follower means on the inner end of said clamping pin, said follower means engaging said compound camming surface in following relationship, said compound camming surface including a first stage which wedges said follower means and clamping pin relatively rapidly and in a non-self-locking manner during the earlier part of the piston's movement in the pin-extending direction, said compound camming surface including a second stage which wedges said follower means and clamping pin relatively slowly and in a self-locking manner during the latter part of the piston's movement in the pin-extending direction. 
     
     
       2. A device as in claim 1, said first stage of said compound camming surface means comprising a relatively steeply angled cam face, said second stage of said compound camming surface means comprising a relatively shallowly angled cam face, said follower means including means to followingly engage said relatively steeply angled cam face and also including a follower face angled correspondingly to said shallowly angled cam face and adapted to be slidingly wedgingly engaged thereby in said self-locking manner. 
     
     
       3. A device as in claim 1, said first stage of said compound camming surface means comprising a relatively steeply angled cam face, said second stage of said compound camming surface comprising a relatively shallowly angled cam face, said follower means including a follower roller to followingly engage said relatively steeply angled cam face in said non-self-locking manner and then to followingly engage said shallowly angled cam face in said self-locking manner as said piston moves in the pin-extending direction. 
     
     
       4. A relatively compact mechanically self-locking quick-acting hydraulic clamping device comprising a body, a primary bore extending through said body from one end to the other, a secondary bore intersecting said primary bore and extending normally to said primary bore from a central portion thereof to a side face of said body, a double-ended piston slidably received in said primary bore and passing back and forth past the intersection between the primary and secondary bores, means defining a piston chamber at each end of said primary bore, compound camming surface means on one side of said piston between the ends thereof and positioned to pass back and forth over said secondary bore during said back and forth movement of said piston to present different stages of said compound camming surface means, a clamping pin in said secondary bore, said pin being spring-biased toward said camming surface means, follower means on the inner end of said clamping pin, said follower means engaging said compound camming surface in following relationship, said compound camming surface including a first stage which wedges said follower means and clamping pin relatively rapidly and in a non-self-locking manner during the earlier part of the piston's movement in the pin-extending direction, said compound camming surface also including a second stage which wedges said follower means and clamping pin relatively slowly and in a self-locking manner during the latter part of the piston's movement in the pin-extending direction. .Iadd. 
     
     
       5.  A relatively compact mechanically self-locking quick-acting hydraulic clamping device comprising a body, a primary bore extending through said body from one end to the other, a secondary bore intersecting said primary bore and extending substantially normal to said primary bore from a central portion thereof to a side face of said body, a double-ended piston slidably received in said primary bore and passing back and forth past the intersection between said primary and secondary bores, means defining a piston chamber at each end of said primary bore, camming surface means on one side of said piston between the ends thereof and positioned to pass back and forth over said secondary bore during said back-and-forth movement of said piston to present different portions of said camming surface means, a clamping pin in said secondary bore, said pin being spring-biased toward said clamping surface means, follower means on the inner end of said clamping pin, said follower means engaging said camming surface means in following relationship, said camming surface including a locking portion which wedges said follower means and clamping pin in a self- locking manner during the piston's movement in a pin-extending direction. .Iaddend. .Iadd. 
     
     
       6.  A relatively compact clamping device as set forth in claim 5, wherein said secondary bore has a substantially uniform diameter, said clamping pin has a head portion substantially adjacent to said camming surface means sized to closely fit the walls of said secondary bore and a reduced cross section shank portion extending with clearance along said secondary bore from the side of said head portion remote from said camming surface means, said spring bias being provided by a coil spring within said secondary bore surrounding said shank and engaging at one end with said head portion. .Iaddend. .Iadd.7. A relatively compact clamping device as set forth in claim 6, wherein retaining means are mounted in said body which extend into said secondary bore and engage the end of said spring opposite said head portion. .Iaddend. .Iadd.8. A relatively compact clamping device as set forth in claim 7, wherein said retaining means is tubular and also engages and guides said shank. .Iaddend. .Iadd.9. A relatively compact clamping device as set forth in claim 8, wherein said camming surface means provides a compound surface including a non-locking section initially operable to engage said follower means and cause rapid movement of said clamping pin prior to engagement between said locking 
     
     
        portion and said follower means. .Iaddend. .Iadd.10.  A compact self-locking hydraulic clamping device comprising a body, a primary bore extending from an end of said body, a secondary bore intersecting said primary bore intermediate its ends and extending substantially normal to said primary bore from said primary bore to a face of said body, a piston slidably received in said primary bore including a piston shank passing back and forth past the intersection between the primary bore and secondary bore, piston chamber defining means associated with said primary bore, camming surface means extending along one side of said piston shank and positioned to pass back and forth over said secondary bore during said back-and-forth movement of said piston to present portions of said camming surface means, a clamping pin in said secondary bore, said pin being biased toward said camming surface means by a spring located in said secondary bore, a key preventing rotation of said clamping pin with respect to said body, follower means on the inner end of said clamping pin, said follower means engaging said camming surface means in follower relationship, said camming surface means including a portion which wedges said follower means and clamping pin in self-locking manner during a part of the piston movement in the pin-extending direction. .Iaddend. 
     
     
        .Iadd.     A relatively compact mechanically self-locking quick-acting hydraulic clamping device comprising a body, a primary bore in said body having ends and extending between said ends and providing a substantially uniform cross section, a secondary bore intersecting said primary bore intermediate its ends and extending substantially normal to said primary bore from one side thereof, a double-ended piston slidably received in said primary bore and passing back and forth past the intersection of said primary and secondary bores, means defining a piston chamber at each end of said piston, said piston providing a self-locking cam surface intermediate its ends on one side thereof positioned to pass back and forth over said secondary bore during said back-and-forth movement of said piston, a clamping pin in said secondary bore providing follower means at the inner end thereof engaging said cam surface in following relationship, the side of said piston opposite said cam surface closely fitting the adjacent surface of said primary bore, pressure in one of said piston chambers causing movement of said piston in an extending direction wedging said piston between said follower means and the adjacent remote wall of said bore with locking engagement, pressure in the other of said piston chambers producing retracting movement of said piston and releasing said 
     
     
        locking engagement. .Iaddend. .Iadd.12.  A compact self-locking hydraulic clamping device comprising a body, a primary bore extending from an end of said body, a secondary bore intersecting said primary bore intermediately and extending normally to said primary bore from said primary bore to a face of said body, a piston slidably received in said primary bore and including a shank passing back and forth past the intersection between the primary and secondary bores, piston chamber defining means associated with said primary bore, compound camming surface means extending along one side of said piston shank and positioned to pass back and forth over said secondary bore during said back and forth movement of said piston to present different stages of said compound camming surface means, a clamping pin in said secondary bore, said pin being biased toward said camming surface means by a spring located in said secondary bore, a key preventing rotation of said clamping pin with respect to said body, follower means on the inner end of said clamping pin, said follower means engaging said compound camming surface in following relationship, said compound camming surface including a first stage which wedges said follower means and clamping pin relatively rapidly and in a non-self-locking manner during the earlier part of the piston's movement in the pin-extending direction, said compound camming surface including a second stage which wedges said follower means and clamping pin relatively slowly and in a self-locking manner during the latter part of the piston's movement in the pin-extending direction. .Iaddend.