Fluid pressure operated press-riveting device

Abstract

The present application pertains to a fluid pressure operated press-riveting device, comprising: a cylinder having a distal end, a proximal end and a sidewall extending axially between the distal end and the proximal end, wherein the distal end has an opening section; a first piston in the cylinder, which defines a first inner chamber with the proximal end and has a press-riveting rod extending towards the distal end and aligned with the opening section; a second piston in the cylinder, which defines a second inner chamber with the distal end, and has a sleeve section extending to the distal end, which at least extends to and closes the opening section and can accommodate the press-riveting rod; a fluid pump system, which is respectively connected with the first inner chamber and the second inner chamber to supply fluid thereto or suck fluid back therefrom, so that the first piston and the second piston move axially along the cylinder, when the second piston moves to the distal end, the sleeve section moves to a pre-compression position, and then the press-riveting rod protrudes out for press-riveting; a force transmission member disposed between the first piston and the second piston, wherein when the sleeve section reaches the pre-compression position, the first piston can approach the second piston, and apply a pressing force to the second piston through the force transmission member.

What is claimed is: 
     
         1 . A fluid pressure operated press-riveting device, comprising:
 a cylinder having a distal end and a proximal end disposed opposite to each other, and a sidewall extending axially between the distal end and the proximal end, wherein the distal end has an opening section;   a first piston, wherein the first piston is disposed in the cylinder and defines a first inner chamber together with the proximal end, and wherein the first piston has a press-riveting rod extending towards the distal end and aligned with the opening section;   a second piston, wherein the second piston is disposed in the cylinder and defines a second inner chamber together with the distal end, the second piston has a sleeve section extending towards the distal end, the sleeve section extends at least to the opening section to close the opening section, and the sleeve section slidably accommodates the press-riveting rod;   a fluid pump system, wherein the fluid pump system is in fluid communication with the first inner chamber and the second inner chamber, respectively, and is used to supply fluid thereto or suck fluid back therefrom, so that the first piston and the second piston can reciprocate axially along the cylinder, and wherein when the first piston and the second piston move from the proximal end to the distal end, the sleeve section moves to a pre-compression position, and then the press-riveting rod protrudes out of the sleeve section to perform a press-riveting operation on a workpiece to be press-riveted; and   a force transmission member disposed between the first piston and the second piston, wherein when the sleeve section of the second piston reaches the pre-compression position, the first piston can approach the second piston and apply a pressing force to the second piston through the force transmission member.   
     
     
         2 . The fluid pressure operated press-riveting device of  claim 1 , wherein the force transmission member comprises a spring element with its two ends connected with the first piston and the second piston, respectively. 
     
     
         3 . The fluid pressure operated press-riveting device of  claim 2 , wherein the spring element is a Belleville spring element. 
     
     
         4 . The fluid pressure operated press-riveting device of  claim 1 , wherein the force transmission member comprises a third inner chamber defined jointly by the first piston, the second piston and the sidewall of the cylinder, and the fluid pump system is also in fluid communication with the third inner chamber to supply fluid thereto or suck fluid back therefrom. 
     
     
         5 . The fluid pressure operated press-riveting device of  claim 4 , wherein a pressure regulating valve is disposed between the third inner chamber and the fluid pump system to adjust a fluid pressure in the third inner chamber. 
     
     
         6 . The fluid pressure operated press-riveting device of  claim 1 , wherein a press-riveting end is disposed at an end of the press-riveting rod. 
     
     
         7 . The fluid pressure operated press-riveting device of  claim 6 , wherein the press-riveting end is detachably connected with the press-riveting rod. 
     
     
         8 . The fluid pressure operated press-riveting device of  claim 6 , wherein the sleeve section comprises a stop element to limit a length of the press-riveting end protruding from the sleeve section. 
     
     
         9 . The fluid pressure operated press-riveting device of  claim 1 , wherein a seal is disposed at a contact portion of the first piston or the second piston with a surface of the cylinder. 
     
     
         10 . The fluid pressure operated press-riveting device of  claim 1 , wherein the press-riveting device further comprises a displacement sensor connected with the first piston and configured to indicate an axial position of the first piston. 
     
     
         11 . The fluid pressure operated press-riveting device of  claim 1 , wherein the fluid pump system comprises a fluid pump, and the first inner chamber and the second inner chamber are in fluid communication with each other through the fluid pump. 
     
     
         12 . The fluid pressure operated press-riveting device of  claim 1 , wherein the fluid supplied and sucked by the fluid pump system is hydraulic oil.