Abstract:
A clamp system includes a frame, a plurality of clamp members, an actuator collar, and an actuator system. The frame includes an attachment member and a stop ring defining a stop cam surface. The clamp members each define first and second cam surfaces. The actuator collar defines an actuator cam surface. The actuator system displaces the actuator collar. The frame supports the actuator collar and the plurality of clamp members such that the first cam surfaces engage the actuator cam surface and the second cam surfaces engage the stop cam surface. Operation of the actuator system displaces the actuator collar towards the stop ring. As the actuator collar moves towards the stop ring, the actuator cam surface acts on the first cam surfaces and the stop cam surface acts on the second cam surfaces such that the clamp members place the clamp system in an engaged configuration.

Description:
RELATED APPLICATIONS 
     This application Ser. No. 13/077,664 claims the benefit of priority of U.S. Provisional Application Ser. No. 61/320,452, filed Apr. 2, 2010. 
     The contents of all related application(s) set forth above are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to pile driving systems and, more particularly, to pile driving systems adapted to drive and/or extract hollow pile members such as pipes. 
     BACKGROUND 
     Construction projects often require the placement of rigid elongate members into the ground. The rigid elongate members can manufactured from various shapes, sizes, and materials depending upon the intended use. The present invention is of particular significance in the context of driving a hollow pipe, such as a pipe pile or caisson, into the ground. For the purposes of describing the construction and use of the present invention, the term “pile” will be used herein to refer to any pile or caisson at least a portion of which is hollow. 
     Piles can be placed at a desired location in the ground using any one of a number of different methods. A hole can be excavated at the desired location, the pile inserted, and then backfill material can be arranged within the hole around the pile to secure the pile in place. More commonly, however, piles are driven into the ground using a pile driving system. A pile driving system typically applies a driving force on an upper end of the pile that drives or crowds the pile into the earth without excavation. 
     In some situations, the pile driving system combines a static driving force with vibratory forces to facilitate the driving and/or extracting of the pile. The static driving force is typically formed by the weight of the pile and the pile driving system and is directed along a drive axis that is substantially defined by a longitudinal axis of the pile. Typically, a support structure such as a crane is used to suspend the pile driving system and pile during operation of the pile driving system to insert and/or extract the pile. 
     The vibratory forces of a pile driving system that uses such forces are typically formed by a vibratory system that creates movement in both directions along the drive axis. A pile driving system that employs vibratory forces also typically employs a clamp system  20  to secure the vibratory system to the pile to ensure that the vibratory forces are effectively transmitted to the pile. In addition, a pile driving system employing vibratory forces further typically employs a suppressor for inhibiting the transmission of vibratory forces to the support structure. 
     The present invention relates to improved clamp system  20 s and methods for vibratory pile driving systems for driving and/or extracting hollow piles such as pipe piles and caissons. 
     SUMMARY 
     The present invention may be embodied as a clamp system for connecting a vibratory system defining a drive axis to a pile defining a pile inner surface. The clamp system comprises a frame, a plurality of clamp members, an actuator collar, and an actuator system. The frame comprising an attachment member adapted to be operatively connected to the vibratory system and a stop ring defining a stop cam surface. The plurality of clamp members defines first and second cam surfaces. The actuator collar defines an actuator cam surface. The actuator system displaces the actuator collar. The frame supports the actuator collar and the plurality of clamp members such that the first cam surfaces engage the actuator cam surface and the second cam surfaces engage the stop cam surface. Operation of the actuator system displaces the actuator collar towards the stop ring. As the actuator collar moves towards the stop ring, the actuator cam surface acts on the first cam surfaces and the stop cam surface acts on the second cam surfaces such that the clamp members are displaced away from the drive axis to place the clamp system in an engaged configuration. The clamp members are adapted frictionally to engage the pile inner surface when the clamp system is in the engaged configuration. 
     The present invention may also be embodied as a method of connecting a vibratory system defining a drive axis to a pile defining a pile inner surface, the method comprising the following steps. A frame comprising an attachment member adapted to be operatively connected to the vibratory system and a stop ring defining a stop cam surface is provided. A plurality of clamp members each defining first and second cam surfaces is provided. An actuator collar defining an actuator cam surface is arranged such that the actuator cam surface engages the first cam surfaces defined by the plurality of clamp members. The plurality of clamp members are arranged relative to the frame such that the stop cam surface defined by the stop ring engages the second cam surfaces. An actuator system for displacing the actuator collar is provided. The actuator system is operated to displace the actuator collar towards the stop ring such that the actuator cam surface acts on the first cam surfaces and the stop cam surface acts on the second cam surfaces to displace the clamp members away from the drive axis to place the clamp system in an engaged configuration in which the clamp members are adapted frictionally to engage the pile inner surface. 
     The present invention may also be configured as a clamp system for connecting a vibratory system defining a drive axis to a pile defining a pile inner surface, the clamp system comprising a frame, a plurality of clamp members, an actuator collar, and an actuator system. The frame comprises an attachment member adapted to be operatively connected to the vibratory system, a stop ring defining a stop cam surface, and a center member for fixing a distance between the attachment member and the stop ring. The plurality of clamp members is secured to the center member for limited motion along the drive axis and radially from the drive axis. Each clamp member defines first and second cam surfaces. The actuator collar defines an actuator cam surface. The actuator system displaces the actuator collar. The frame supports the actuator system and the actuator collar such that the first cam surfaces engage the actuator cam surface and the second cam surfaces engage the stop cam surface. Operation of the actuator system displaces the actuator collar towards the stop ring. As the actuator collar moves towards the stop ring, the actuator cam surface acts on the first cam surfaces and the stop cam surface acts on the second cam surfaces such that the clamp members are displaced away from the drive axis to place the clamp system in an engaged configuration. The clamp members are adapted frictionally to engage the pile inner surface when the clamp system is in the engaged configuration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation view of an example pile driving system incorporating an example of an internal pipe claim system of the present invention; 
         FIG. 2  is a side elevation view of the example of the internal pipe clamp system  20  depicted in  FIG. 1 ; 
         FIG. 3  is a side section view of the example internal pipe clamp system  20  of  FIG. 1  in a disengaged configuration; and 
         FIG. 4  is a side section view of the example internal pipe clamp system  20  of  FIG. 1  in an engaged configuration. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  depicts a clamp system  20  forming part of a pile driving system  22  for driving a pile  24  into a desired location  26  in the earth  28 . The example pile  24  is hollow and, more particularly, takes the form of a pipe or pipe pile. 
     In  FIG. 1 , the example pile driving system  22  comprises, in addition to the clamp system  20 , a vibratory system  30  and a suppressor system  32 . The pile driving system  22  and pile  24  are supported by a support structure  34  comprising a crane  36  and a crane line  38 . The example crane line  38  is operatively connected to the suppressor  32 , and the example suppressor  32  is rigidly connected to the vibratory system  30 . The example vibratory system  30  is in turn rigidly connected to the clamp system  20 . The example clamp system  20  substantially rigidly connects vibratory system  30  to the pile  24 . 
     In general, the clamp system  20  is connected to the vibratory system  30  such that the vibratory forces are substantially rigidly transmitted or transferred from the vibratory system  30  to the clamp system  20 . The clamp system  20  in turn engages the pile  24  such that the vibratory forces are substantially rigidly transmitted or transferred from the clamp system  20  to the pile  24  as will be described in further detail below. 
       FIG. 2  illustrates that the example clamp system  20  comprises a frame  40 , an actuator collar  42 , a plurality (two or more) clamp assemblies  44 , and an actuator system  46 .  FIGS. 3 and 4  illustrate that the example frame  40  comprises an attachment member  50 , a center member  52 , a stop ring  54 , a guide member  56 , and a plurality (two or more) of cylinder flanges  58 . 
     The example attachment member  50  takes the form of a beam that is adapted to be rigidly connected to the vibratory system  30  such that the attachment member  50  is substantially symmetrically arranged about a drive axis A defined by the vibratory system  30 . The attachment member  50  is rigidly connected to a base location of the center member  52  such that the center member  52  substantially symmetrically extends along the drive axis A. 
     The example stop ring  54  is rigidly connected to the center member  52  at an intermediate location along the length of the center member  52 . The guide member  56  is rigidly connected at an end location of the center member  52  distal from the attachment member  50 . The intermediate location is spaced between the end location and the base location. 
     The example cylinder flanges  58  are rigidly connected to the attachment member  50  and/or the center portion  52  such that the cylinder to flanges  58  extend along the drive axis A and radially extend from the drive axis A. 
     The example clamp assemblies  44  each comprise a clamp member  60  operatively connected by at least one retaining bolt  62  such that the clamp members  60  may move between a disengaged position ( FIG. 3 ) and an engaged position ( FIG. 4 ) relative to the center member  52 . Return springs  64  are configured to bias the clamp members  60  into the disengaged position. The example clamp members  60  are arranged in groups of two opposing clamp members. The example clamp system  20  comprises four of the example clamp assemblies  44 , so the example clamp members  60  are arranged in two groups of two, with each clamp member  60  arranged on an opposite side of the drive axis A from the other clamp member  60  in its group. In addition, in the example clamp system  20 , each clamp member  60  is provided with two of the retaining bolts  62  and two of the return springs  64 . 
     When moving between the disengaged and engaged positions, the example clamp members  60  move both along the drive axis A and radially with respect to the drive axis A. In particular, at least one slot  66  is formed in each of the clamp members  60  to allow movement of the clamp members  60  within a limited range of movement along the drive axis A. In this context, the retaining bolts  62  and compression and expansion of the return springs  64  allow movement of the clamp members  60  within a limited range radially with respect to the drive axis A. In the example clamp system  20 , one of the slots  66  is provided for each of the retaining bolts  62 , so two slots  66  are formed in the example clamp members  60 . 
     The example actuator system  46  comprises at least one actuator  70  comprising a cylinder  72  and a shaft  74 . As is conventional, energizing the actuator  70  in at least a first mode causes the shaft  74  to be extended from a retracted configuration ( FIG. 3 ) towards an extended configuration ( FIG. 4 ) relative to the cylinder  72 . Optionally, the actuator  70  may be energized in a second mode in which the shaft is retracted from the extended configuration towards the retracted configuration with respect to the cylinder  72 . The actuators  70  may be pneumatic, electrical, or hydraulic devices as necessary to exert sufficient clamping force as will be described in further detail below. The example actuators  70  are conventional hydraulic devices powered by pressurized hydraulic fluid. The example actuator system  46  of the example clamp system  20  comprises four actuators, one for each of the clamp assemblies  44 . The example actuator system  46  further comprises an actuator housing  76  that extends from the attachment member  50  and protects the actuator system  46 . 
     A cylinder coupler  80  is rigidly secured to the cylinder  70 , and a cylinder pin  82  operatively connects the cylinder  72  for pivoting movement relative to the cylinder flange  58  of the frame  40 . A shaft coupler  84  is rigidly secured to the shaft  74 , and a shaft pin  82  operatively connects the shaft  74  for pivoting movement relative to a shaft flange  88  forming part of the actuator collar  42  of the example clamp system  20 . 
     The actuator collar  42  defines an actuator cam surface  90 , while the stop ring  54  defines a stop cam surface  92 . Each of the clamp members  60  defines a first cam surface  94  and a second cam surface  96 . The actuator cam surface  90  and the first cam surface  94  are configured to extend at a first angle with respect to the drive axis A, while the stop cam surface  92  and the second cam surface  96  are configured to extend at a second angle with respect to the drive axis A. 
     Accordingly, with the actuator collar  42  pivotably connected to the actuators  70  and the clamp members  60  movably secured relative to the center member  52  as depicted in  FIGS. 3 and 4 , the return springs  64  bias the clamp members  60  towards the drive axis A such that the first cam surfaces  94  engage the actuator cam surface  90 . Similarly, with the stop ring  54  rigidly supported by the center member  52  and the clamp members  60  movably secured relative to the center member  52  as depicted in  FIGS. 3 and 4 , the return springs  64  bias the clamp members  60  towards the drive axis A such that the second cam surfaces  96  engage the stop cam surface  92 . 
     With reference to  FIGS. 3 and 4 , the use of the example clamp assembly  20  will now be described in further detail. Initially, it should be noted that the pile  24  comprises a pile upper edge  120 , a pile inner surface  122 , and a pile outer surface  124 . The pile upper edge  120  defines a pile opening  126 , and the pile inner surface  122  defines a pile chamber  128 . The pile  24  further defines a pile axis B. 
     To begin the process of engaging the clamp system  20  with the pile  24 , the actuators  70  are first arranged in the retracted configuration such that the clamp members  60  are in the disengaged configuration. The pile driving system  22  is then displaced such that the clamp system  20  is inserted at least partly through the pile opening  126  and substantially arranged within the pile chamber  128 . The guide member  56  defines slanted guide surfaces  130  that engage the pile upper edge  120  and guide the clamp system  20  through the pile opening  126  and into the pile chamber  128 . The clamp system  20  may be arranged such that the pile upper edge  120  engages the attachment member  50 , or the pile upper edge  120  may be spaced from the attachment member  50 .  FIGS. 3 and 4  illustrate the situation in which the pile upper edge  120  engages the attachment member  50 . At this point, the drive axis A may not be aligned with the pile axis B. 
     The actuators  70  are next energized in the first mode to extend the shafts  74  relative to the cylinders  72 . As the shafts  74  move towards the extended configuration, the actuator collar  42  is displaced along the drive axis A away from the attachment member  50  and towards the stop ring  54 . As the actuator collar  42  moves towards the stop ring  54 , the actuator cam surface  90  engages the first cam surfaces  94  and the stop cam surface  92  engages the second cam surfaces  94 . To accommodate this displacement of the movable actuator collar  42  relative to the fixed stop ring  54 , the respective cam surfaces  90  and  92  engage the associated cam surfaces  94  and  96 , respectively, to cause the clamp members  60  to move away from the drive axis A. The return springs  64  compress to allow the movement of the clamp members  60  away from the drive axis A. 
     Eventually, the distance between outer surfaces  140  of the clamp members  60  equals the distance between opposite portions of the pile inner surface  122  and the clamp members  60  engage the pile  24 . The clamp members  60  frictionally engage the pile  24  at this point. Additionally, the clamp system  20  will selfcenter such that the drive axis A is substantially aligned with the pile axis B. 
     It should be noted that the actuator system  46  and clamp assemblies  44  should be configured such that the distance between opposing outer surfaces  140  of the clamp members  60  may be greater than the inner diameter of the pile  24  when the actuators  70  are in the fully extended configurations. The actuators  70  may thus be configured to apply sufficient clamping pressure to the clamp members  60  such that the clamp members frictionally engage the pile inner surface  122  to inhibit movement of the clamp members  60  relative to the pile during normal operation of the pile driving system  22 . The pile driving system  22  is then operated to drive the pile  24  to a desired depth at the desired location  26 . 
     To disengage the clamp system  20  from the pile  24 , the actuators  70  may be placed in a de-energized configuration to allow the return springs to force the clamp members  60  towards the drive axis A and thus the actuator collar  42  towards the attachment member  50 , thereby forcing the shafts  74  towards the retracted configuration with respect to the cylinders  72 . Optionally, the actuators  70  may be energized in the second mode to force the shafts into the retracted configuration. At some point between the engaged configuration and the disengaged configuration, the clamp members  60  disengage from the pile inner surfaces  122 , allowing the clamp system  20  to be removed from the pile chamber  128 . 
     A clamp system such as the example clamp system  20  described above allows the pile  24  to be driven without engaging the pile external surface.