Abstract:
A clamp system for operatively connecting a vibratory device to a plurality of caissons defining at least first and second diameters comprises a structural member, first and second clamps comprising first and second lock systems, respectively, and a clamp displacement system. The first and second clamps are supported by the structural member. The first and second lock systems fix the first and second clamps relative to the structural member. The clamp displacement system comprises at least one clamp displacement motor supported by the structural member and a mechanical link assembly connected between the at least one clamp displacement motor and the first and second clamps. Operation of the at least one clamp displacement motor allows the first and second clamps to be remotely displaced relative to the structural member such that the first and second clamps are spaced along the structural member as appropriate for either of the first and second diameters. Operation of the first and second locks systems fixes the first and second clamps relative to the structural member.

Description:
RELATED APPLICATIONS 
     This application 12/330,464 is a continuation of pending U.S. patent application Ser. No. 11/137,219, filed May 24, 2005. 
     U.S. patent application Ser. No. 11/137,219 is a continuation of U.S. patent application Ser. No. 10/716,918, filed Nov. 18, 2003, now U.S. Pat. No. 6,896,448 issued May 24, 2005. 
     U.S. patent application Ser. No. 10/716,918 is a continuation-in-part of 10/352,760 filed Jan. 27, 2003, now U.S. Pat. No. 6,648,556 issued Nov. 18, 2003. 
     U.S. patent application Ser. No. 10/352,760 is a continuation of U.S. patent application Ser. No. 09/921,106 filed Aug. 1, 2001, abandoned. 
     U.S. patent application Ser. No. 09/921,106 claims benefit of U.S. Provisional Patent Application Ser. No. 60/222,347 filed Aug. 1, 2000. 
     The subject matter of the foregoing related applications is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to clamping assemblies for pile drivers and, more specifically, to clamping assemblies that allow vibratory pile drivers to be connected to caissons for driving caissons into the earth. 
     BACKGROUND OF THE INVENTION 
     Modern construction design often requires caissons to be driven into the earth at desired locations. In the context of the present invention, the term “caisson” will be used to refer to hollow, cylindrical members that are driven into the earth. Caissons are normally used as part of the footing for a structural element such as a building foundation or bridge pier, but the end use of the caisson is not a part of the present invention. 
     Pile driving systems that impart vibratory loads are highly effective at driving elongate members such as piles, caissons, and the like into the earth. The vibratory forces of such vibratory pile deriving systems must be transmitted to the member to be driven by a clamping assembly. The clamping assembly ensures that the vibratory forces in both directions are applied to the member to be driven. 
     In the case of caissons, the clamping assembly conventionally comprises a rigid structural member or assembly on which are mounted two or more hydraulic clamps. The hydraulic clamps are spaced from each other along the structural member to grip the upper edge of the caisson such that the vibratory loads are symmetrically applied along the centerline of the caisson. 
     A basic clamping assembly for relatively small-diameter caissons comprises a single structural member and two hydraulic clamps. The hydraulic clamps are movable along the structural member to allow the clamping assembly to accommodate caissons of different diameters within a range defined by the length of the structural member. 
     Conventionally, the hydraulic clamps are moved by hand to desired locations on the structural member and fixed. The entire assembly is then lifted to the top of the caisson and displaced such that the top edge of the caisson enters the hydraulic clamps. The clamps are then actuated to grip the caisson and the process of driving the caisson can be commenced. 
     The need thus exists for improved caisson clamping systems that simplify the process of attaching a vibratory device to a caisson to be driven into the earth. 
     RELATED ART 
     The following prior art references illustrate the background of the present invention. 
     U.S. Pat. No. 5,653,556 to White discloses a clamp system for connecting caissons to a vibratory driver/extractor. The clamp system employs a beam assembly that supports four clamps at locations angularly spaced about the circumference of the caisson. 
     U.S. Pat. No. 5,544,979 to White discloses a clamp system for connecting caissons or piles to a vibratory pile driver/extractor in which the clamp engages a side surface rather than an upper end of the caisson or pile. 
     U.S. Pat. Nos. 5,117,925 and 5,263,544 to White disclose shock absorbing systems for use with a vibratory pile driver/extractor. These shock absorbing systems could be used with the clamp systems and methods of the present invention. 
     U.S. Pat. No. 5,609,380 to White discloses a clamp assembly for connecting a vibratory pile/extractor to a pile. Clamping forces are applied to the sides of the pile. 
     SUMMARY OF THE INVENTION 
     The present invention may be embodied as a clamp system for operatively connecting a vibratory device to a plurality of caissons defining at least first and second diameters. One example clamp system of the present invention comprises a structural member, first and second clamps comprising first and second lock systems, respectively, and a clamp displacement system. The first and second clamps are supported by the structural member. The first and second lock systems fix the first and second clamps relative to the structural member. The clamp displacement system comprises at least one clamp displacement motor supported by the structural member and a mechanical link assembly connected between the at least one clamp displacement motor and the first and second clamps. Operation of the at least one clamp displacement motor allows the first and second clamps to be remotely displaced relative to the structural member such that the first and second clamps are spaced along the structural member as appropriate for either of the first and second diameters. Operation of the first and second locks systems fixes the first and second clamps relative to the structural member. 
     The present invention may also be embodied as a method of operatively connecting a vibratory device to a plurality of caissons defining at least first and second diameters. One example method of the present invention comprises the following steps. First and second clamps are movably supported on a structural member. At least one clamp displacement motor is supported on the structural member. The at least one clamp displacement motor is mechanically connected to the first and second clamps. The at least one clamp displacement motor is operated such that the first and second clamps are remotely displaced relative to the structural member such that the first and second clamps are spaced along the structural member as appropriate for either of the first and second diameters. The first and second locks systems are operated to fix the first and second clamps relative to the structural member. 
     Other features and aspects of the present invention will become apparent from the following detailed description of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation view depicting a caisson driving system employing a clamp assembly constructed in accordance with the present invention being used to drive a caisson; 
         FIG. 2  is a front elevation view of the clamping assembly depicted in  FIG. 1  in a first configuration; 
         FIG. 3  is a top plan view of the clamping assembly of  FIG. 1  taken along lines  3 - 3  in  FIG. 2 . 
         FIG. 4  is a front elevation view of the clamping assembly depicted in  FIG. 1  in a second configuration; 
         FIG. 5  is a top plan view of the clamping assembly of  FIG. 1  taken along lines  5 - 5  in  FIG. 4 ; 
         FIG. 6  is a somewhat schematic, top plan view of a first alternate clamp displacement system that may be used by the clamping assembly of  FIG. 1 ; 
         FIG. 7  is a somewhat schematic, top plan view of a second alternate clamp displacement system that may be used by the clamping assembly of  FIG. 1 ; 
         FIG. 8  is a somewhat schematic, front elevation, partial cutaway view of the clamp displacement system of  FIG. 7 ; and 
         FIG. 9  is an end elevation section view taken along lines  9 - 9  in  FIG. 2 . 
         FIG. 10  is a top plan view of a clamp displacement system of a third alternate clamp displacement system that may be used by the clamping assembly of  FIG. 1 ; 
         FIG. 11  is side elevation view of the clamp displacement system of  FIG. 10 ; and 
         FIGS. 12 and 13  are top plan views depicting the operation of the clamp displacement system of  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring initially to  FIG. 1  of the drawing, depicted therein is a caisson driving system  20  employing a clamp assembly  22  constructed in accordance with, and embodying, the principles of the present invention. The exemplary caisson driving system  20  is shown driving a caisson  24 . 
     The caisson driving system  20  further comprises a crane  30  having a crane cable  32 , a suppression assembly  34  suspended from the crane  30  by the crane cable  32 , and a vibratory device  36  rigidly connected to the suppression assembly  34 . The vibratory device  36  is rigidly connected to the clamp assembly  22 , and the clamp assembly is detachably clamped onto the caisson  24 . The caisson  24 , crane  30 , crane cable  32 , suppression assembly  34 , and vibratory device  36  all are or may be conventional and will not be described in detail herein. 
     Referring now to  FIGS. 2-5 , these figures show that the clamp assembly  22  comprises a structural member or beam  40 , first and second clamps  42  and  44 , and a clamp displacement system  46 . 
     The structural member  40  has a central portion  50  and first and second rail projections  52  and  54  laterally extending from the center portion  50 . As shown in  FIG. 9 , the structural member  40  further comprises first and second upper projections  56  and  58  extending from the central portion  50 . In the exemplary clamping assembly  20 , the first and second rail projections  52  and  54  are co-planar, the first and second upper projections  56  and  58  are co-planar and parallel to the first and second rail projections  52  and  54 , and all of these projections are perpendicular to the central portion  50 ; the exemplary structural member  40  is thus an I-beam. 
     As perhaps best shown in  FIG. 9 , the clamps  42  and  44  each comprise first and second rail brackets  60  and  62  each having upward extending portions  64  and inwardly extending portions  66 . The inwardly extending portions  66  define a slot  68  that receives the center portion  50  of the structural member  40 ; however, the slot  68  is narrower than the combined dimensions of the rail projections  52  and  54 . The rail brackets  60  and  62  thus engage the rail projections  52  and  54  such that, during normal operation, the clamps  42  and  44  may move horizontally along the structural member  40  but may not move down relative to the structural member  40 . 
     As perhaps best shown in  FIGS. 2-5 , the clamps  42  and  44  each further comprise a main housing  70 , a hydraulic clamping system  72 , and a hydraulic locking system  74 . The hydraulic clamping system  72  and locking systems  74  are mounted to the main housing. These systems  72  and  74  are or may be conventional and will not be described herein beyond the extent necessary for a complete understanding of the present invention. 
     The clamping system  72  engages the upper edge of the caisson  24  selectively to fix the caisson  24  relative to the clamps  42  and  44  through the clamp housings  70 . The locking system  74  engages the structural member  40  selectively to prevent relative movement between the clamps  42  and  44  and the structural member  40 . As generally discussed above, the clamping systems  72  and locking systems  74  each comprise a physical assembly corresponding to the structure identified by reference characters  42  and  44  in the drawing. As will be discussed in further detail below, these systems  72  and  74  further comprise a hydraulic portion that operates the physical assembly in a known manner to obtain the result described herein. 
     The clamping system  72  and locking system  74  are thus both actuated to fix the position of the caisson  24  relative to the structural member  40 ; both the clamping system  72  and the clocking system  74  will be actuated during driving of the caisson  24 . During adjustment of the positions of the clamps  42  and  44  (as will be described in further detail below), the clamps  42  and  44  will be disengaged from the caisson  24  (with the clamping systems  72  de-actuated), and the locking systems  74  must be de-actuated. 
     The exemplary clamp displacement system  46  comprises a drive pinion  80 , first and second rack members  82  and  84 , and first and second guide members  86  and  88 . In the exemplary clamp assembly  22 , the drive pinion  80  is mounted in an opening  90  in the structural member  40  such that its axis of rotation A is vertical and extends substantially through the center of gravity of the structural member  40 . 
     The drive pinion  80  comprises drive teeth  92 , and the rack members  82  and  84  comprise rack teeth  94  and  96  sized and dimensioned to engage the drive teeth  92 . 
     The first rack member  82  is rigidly connected to the first clamp  42 , and the second rack member  84  is rigidly connected to the second clamp  44 . In particular, in the exemplary clamp assembly  22 , when the racks  82  and  84  are attached to the clamps  42  and  44  and the clamps  42  and  44  are supported by the structural member  40  as described above, the racks  82  and  84  extend from their associated clamps in opposite directions on opposite sides of the structural member  40 . In addition, the racks  82  and  84  are spaced on either side of the central portion  50  of the structural member  40  such that the rack teeth  94  and  96  engage the drive teeth  92 . 
     The second guide member  88  is rigidly connected to the first clamp  42 , and the first guide member  86  is rigidly connected to the second clamp  44 . In addition, the first guide member  86  is arranged on an opposing side of the structural member central portion  50  from the first rack member  82 , and the second guide member  88  is arranged on an opposing side of the central portion  50  from the second rack member  84 . 
     When the clamps  42  and  44  are supported by the structural member  40  as described above, the first and second guide members  86  and  88  receive the second and first rack members  84  and  82 , respectively. 
     The guide members  86  and  88  support the rack members  82  and  84  such that these members  82  and  84  stay parallel to each other during normal operation. In particular, when the vibratory device is operating, forces are generated that will tend to rotate the rack members  82  and  84  in a vertical arc centered at the point where the rack members  82  and  84  are attached to the clamps  42  and  44 . The guide members  86  and  88  limit this rotational movement of the rack members  82  and  84  relative to the clamps  42  and  44  and thus reduce fatigue and wear on the rack members  82  and  84 . 
     The exemplary clamping system  72 , locking system  74 , and drive pinion  76  are all operated by pressurized hydraulic fluid. The clamping system  72  and locking system  74  comprise a hydraulic piston assembly that displaces a clamp member when pressurized hydraulic fluid is applied to the piston, while the drive pinion  76  comprises a hydraulic motor that creates rotational motion from pressurized hydraulic fluid. For simplicity and clarity, the source of the pressurized hydraulic fluid is not shown in the drawings, but is or may be conventional. 
     The operation of the clamping system  72 , locking system  74 , and drive pinion  76  may be remotely controlled, for example by an operator of the crane  30 , by controlling the flow of pressurized hydraulic fluid from the source. The design of the fluid control circuitry required to allow the operator to control the clamping and locking systems  72  and  74  and drive pinion  76  is conventional, would be apparent to one of ordinary skill in the art, and will not be described in detail herein. 
     The clamp assembly  22  is operated in the following general manner. Initially, the clamping systems  72  and locking systems  74  are de-actuated. The operator then determines the size, or diameter, of the first caisson to be driven and operates the drive pinion  80  to displace the racks  82  and  84 , and thus the clamps  42  and  44 , along a longitudinal axis B of the structural member  40 . When the effective locations of the clamps  42  and  44  are spaced from each other a distance approximately equaling the diameter of the first caisson to be driven, the drive pinion  80  is stopped. The entire clamp assembly  22  is then displaced until the clamps  42  and  44  receive opposing edge portions of the first caisson to be driven. The drive pinion  80  will engage the racks  82  and  84  to inhibit incidental movement of the clamps  42  and  44  during maneuvering of the clamp assembly  22 . 
     When the caisson edges are received by the clamps  42  and  44 , the clamping systems  72  are actuated to fix the caisson relative to the clamp housings  70 . The locking systems  74  are then actuated to fix the clamp housings  70  relative to the structural member  40 . The caisson driving system  20  may then be used to drive the first caisson. 
     If the remaining caissons to be driven are the same diameter as the first caisson, the clamping systems  72  are de-actuated, the clamp assembly  22  is maneuvered such that the clamps  42  and  44  receive the upper opposing edge portions of the next caisson, and the clamping systems  72  are actuated to fix the position of the new caissons relative to the clamp housings  70 . The caisson driving system  20  may then be used to drive the new caisson. 
     If the next caisson to be driven has a different diameter as the first caisson, the process described above for the first caisson is repeated. The present invention is thus of particular importance in situations where caissons of different diameters are to be driven. For example, a design may call for caissons of a first diameter to be alternated with caissons of a second diameter. The present invention greatly reduces the overall time to drive all of the caissons because the process of reconfiguring the clamp assembly  22  for the different caisson diameters is significantly quicker. 
     Referring now to  FIG. 6 , schematically depicted therein is an alternate clamp displacement system  46   a  that may be substituted for the clamp displacement system  46  described above. This displacement system  46   a  is similar to the system  46  and will be described only to the extent that it differs from the system  46 . 
     The system  46   a  comprises first and second drive pinions  80   a  and  81   a  associated with the racks  82   a  and  84   a , respectively. The axes of rotation C and D of the exemplary drive pinions  80   a  and  81   a  are symmetrically arranged relative to a vertical axis E extending through the center of gravity of the clamp assembly  22 . The use of two drive pinions  80   a  and  81   a  allows the racks  82   a  and  84   a , and thus the clamps  42  and  44  attached thereto, to be independently moved along the structural member  40 . 
     Referring now to  FIGS. 7 and 8 , schematically depicted therein is an alternate clamp displacement system  46   b  that may also be substituted for the clamp displacement system  46  described above. This displacement system  46   b  is similar to the system  46   a  and will be described only to the extent that it differs from the system  46   a.    
     The system  46   b  also comprises first and second drive pinions  80   b  and  81   b  associated with the racks  82   a  and  84   a , respectively. However, the drive pinions  80   b  and  81   b  are stacked such that the axes of rotation of the exemplary drive pinions  80   a  and  81   a  are symmetrically arranged relative to a vertical axis F extending through the center of gravity of the clamp assembly  22 . Like the displacement system  46   a , the system  46   b  employs two drive pinions  80   b  and  81   b  that allow the racks  82   b  and  84   b , and thus the clamps  42  and  44  attached thereto, to be independently moved along the structural member  40 . 
     One variation on the system disclosed in  FIGS. 7 and 8  is to arrange both of the racks  82   b  and  84   b  on the same side of the structural member  40 . Another variation is to align the racks  82   b  and  84   b  with the longitudinal axis of the structural member  40 , in which case the drive pinions  80   b  and  81   b  will be spaced (preferably but not necessarily on opposite sides) from the vertical axis F extending through the center of gravity of the assembly  22 . 
     Referring now to  FIGS. 10-13 , depicted therein is a clamp displacement system  46   c  that may be substituted for the clamp displacement system  46  described above. This displacement system  46   c  is similar to the system  46  and will be described only to the extent that it differs from the system  46 . 
     The clamp displacement system  46   c  comprises a drive gear  120 , a drive chain  122 , a first drive cable  124 , a second drive cable  126 , and a guide roller  128 . A first coupler  130  connects a first end of the drive chain  122  to the first clamp assembly  42 . A second coupler  132  connects a second end of the drive chain  122  to a first end of the first drive cable  124 . A third coupler  134  connects a second end of the first drive cable  124  to the second clamp assembly  44  on a first side of the structural member  40   c . A fourth coupler  136  connects a first end of the second drive cable  126  to the second clamp assembly  44 . A fifth coupler  138  connects a second end of the second drive cable  126  to the first clamp assembly  42  on a second side of the structural member  40   c.    
     The drive chain  122  and first and second drive cables define a closed drive path  140  illustrated by dotted lines in  FIG. 10 . The guide roller  128  engages the second drive cable  136  and the drive gear  120  engages the drive chain  122  such that the drive chain  122  and drive cables  124  and  126  are held in a drive plane  142  shown by dotted lines in  FIG. 142 . The drive plane  142  is defined by the drive path  140 . 
     In addition, the drive chain  122  engages the drive gear  120  such that rotation of the drive gear  120  displaces the drive chain  122  along the drive path  140 . The connections formed by the couplers  130 - 138  described above ensure that, as the drive chain moves along the drive path  140 , the first and second drive cables  124  and  126  are also displaced along the drive path  140 . These connections further displace the clamp assemblies  42  and  44  in the same direction along the drive path  140 . However, because the drive path  140  is a closed loop that extends along both sides of the structural member  40   c , the clamp assemblies  42  and  44  move in opposite directions along a structural axis  144  ( FIG. 10 ) defined by a structural member  40   c.    
     In particular,  FIG. 12  illustrates that, when the drive gear  122  rotates in a first direction  150 , the clamp assemblies  42  and  44  move away from each other along the structural axis  144 .  FIG. 13  illustrates that, when the drive gear  122  rotates in a second direction  152 , the clamp assemblies  42  and  44  move towards each other along the structural axis  144 . The clamp displacement system  46   c  thus may be used in a manner similar to the system  46  described above to allow different caisson diameters to be quickly and easily accommodated. 
     The example structural member  40   c  is an I-beam having a lower flange  160 , an intermediate portion  162 , and an upper flange  164 . The lower flange  160  extends beyond the intermediate portion  162  on each end of the structural member  40   c  to form first and second mounting surfaces  166  and  168  on which the drive gear  122  and guide roller  128 , respectively, are mounted. Other structures may be used to support the drive gear  122  and guide roller  128  within the scope of the present invention, however. 
     In the example clamp displacement system  46   c , first and second guide passageways  170  and  172  ( FIGS. 10 and 11 ) are formed in the first and second clamp assemblies  42  and  44 , respectively. The drive chain  122  and/or first drive cable  124  extend through the first guide passageway  170 . The second drive cable  126  extends through the second guide passageway  172 . The guide passageways  170  and  172  are bores that support the drive chain  122  and first and second drive cables  124  and  126  for movement along the drive path  140 . 
     While the example passageways  170  and  172  are illustrated as bores formed in the housings of the clamp assemblies  42  and  44 , the passageways  170  and  172  may also be formed by grooves are notches formed in or by the clamp assemblies  42  and  44 . The guide passageways  170  and  172  may be omitted but help stabilize the flexible drive chain  122  and drive cables  124  and  126  when the system  46   c  is vibrated. 
     While the example clamp displacement system  46   c  employs first and second drive cables  124  and  126 , the function of these cables  124  and  126  may be formed by a single cable that is fastened to the second clamp assembly  44 . 
     In addition, the drive cables  124  and  126  may be omitted entirely and replaced by a longer drive chain  122  that extends along the drive path  140 . In this case, the drive chain  122  may be a continuous chain extending along the entire drive path  140  and secured at appropriate locations to the first and second clamp assemblies  42  and  44 . Alternatively, the drive chain  122  may be secured at a first end to a first side of the first clamp assembly  42 , at an intermediate point to the second clamp assembly  44 , and at a second end to a second side of the second clamp assembly  42 . 
     Additionally, if a single drive chain is used, the guide roller  128  would be replaced by a driven or non-driven gear that helps support the single drive chain along the drive path  140 . 
       FIG. 11  further depicts an example drive motor  180  for rotating the drive gear  122 . The example drive motor  180  is a hydraulic motor, but the drive motor  180  may be any device cable of generating sufficient power to displace the clamp assemblies  42  and  44  as described above. 
     In any of the embodiments described above, the present invention is preferably embodied as a clamp assembly  22  that is substantially symmetrical about a vertical axis extending through the center gravity of the clamp assembly  22 . Such symmetry helps ensure that the vibratory forces generated by the vibratory device  36  and transmitted to the caisson  24  are applied along the longitudinal axis of the caisson  24 . 
     However, in some situations, it may be possible to obtain a satisfactory clamp assembly according to the present invention that is not completely symmetrical. For example, one of the two clamp assemblies may be fixed and the other adjustable as described above; this arrangement would require only one drive pinion and rack and thus would be simpler to manufacture at the expense of loss of symmetry. 
     In addition, while as few as one clamp may be moved or adjusted with a drive pinion and rack as described above, three, four, or more clamps may be moved in accordance with the present invention in its broadest form. For example, three clamps may be provided on a structural member adapted to arrange the clamps at 120° increments about the circumference of the caisson. In this case, the racks and associated drive pinions would most efficiently be arranged at different horizontal levels so that they do not interfere with each other. 
     In another example, four clamps may be provided on a structural member adapted to arrange the clamps at 90° increments about the caisson circumference. Such a structural member would comprise two cross-arms that intersect at a central location. A likely arrangement for the racks and pinions would be a lower set on either side of one cross-arm and an upper set on either side of the other cross-arm. 
     From the foregoing, it should be clear that the present invention may be embodied in forms other than those described above. The above-described systems are therefore to be considered in all respects illustrative and not restrictive.