vibratory mechanism for a pile driver and a pile driver

Abstract

A vibratory mechanism for a pile driver com-prises a static part and a dynamic part. The dynamic part is movable with respect to the static part. The static part is provided with a drivable crankshaft and the dynamic part comprises a housing and a vibration member. The vibration member is drivably coupled to the crankshaft through a connecting rod and linearly movable with respect to the housing in a direction of vibration. The housing is resiliently coupled to the vibration member.

1 . A vibratory mechanism comprising a static part and a dynamic part being movable with respect to the static part, wherein the static part is provided with a drivable crankshaft and the dynamic part comprises a housing and a vibration member being drivably coupled to the crankshaft through a connecting rod and linearly movable with respect to the housing in a direction of vibration, wherein said housing is resiliently coupled to the vibration member via a fluid spring, wherein the mechanism is adapted such that under operating conditions the vibration member is driven upon driving the crankshaft by a drive device. 
     
     
         2 . The vibratory mechanism according to  claim 1 , wherein the characteristics of the fluid spring is adjustable, preferably such that the natural frequency of the mass-spring system comprising the vibration member and the fluid spring is similar to or approaches the frequency of the crankshaft under operating conditions. 
     
     
         3 . The vibratory mechanism according to  claim 1 , wherein the vibration member is a piston and the housing comprises a cylinder within which the piston is slidable, and the fluid spring is formed by a fluid chamber being present between the piston and the cylinder. 
     
     
         4 . The vibratory mechanism according to  claim 3 , wherein the fluid spring is formed by two fluid chambers located at opposite sides of the piston. 
     
     
         5 . The vibratory mechanism according to  claim 4 , wherein the fluid chambers can communicate with each other through a controllable valve. 
     
     
         6 . The vibratory mechanism according to  claim 1 , wherein the mechanism comprises at least two vibration members, and wherein the mechanism is adapted such that under operating conditions the vibration members can be driven in opposite directions. 
     
     
         7 . The vibratory mechanism according to  claim 6 , wherein the characteristics of the resiliency between the housing and the vibration members is adjustable. 
     
     
         8 . The vibratory mechanism according to  claim 1 , and further comprising a compressor wherein the fluid spring is coupled to the compressor. 
     
     
         9 . The vibratory mechanism according to  claim 1 , wherein the mechanism comprises adjusting means for adjusting the stroke of the vibration member with respect to the eccentricity of the crankshaft. 
     
     
         10 . The vibratory mechanism according to  claim 1 , wherein the housing of the dynamic part and the static part are connected to each other via a spring and/or a damper. 
     
     
         11 . The vibratory mechanism according to  claim 1 , wherein a first part of the connecting rod is guided by a crosshead guide in the static part or in the dynamic part and a second part thereof being fixed to the vibration member is movable along its longitudinal center line only. 
     
     
         12 . The vibratory mechanism according to  claim 1 , wherein the vibration speed of the vibration member, the weight of the housing and the characteristics of the resiliency between the housing and the vibration member are selected such that the vibration member and the housing substantially vibrate in counter phase under operating conditions, and wherein the weight of the vibration member is selected such that its inertia force of the first order substantially balances the inertia force of the housing. 
     
     
         13 . A pile driver comprising a vibratory mechanism according to  claim 1 . 
     
     
         14 . The pile driver according to  claim 13 , wherein the static part comprises a drive device coupled to the crankshaft. 
     
     
         15 . The pile driver according to  claim 14 , wherein the drive device is an internal combustion engine.