Abstract:
A vertical pull apparatus for converting a vertical pulling motion to a horizontal pulling motion, which vertical pull apparatus typically includes a support for positioning in a generally vertical position. A cable-engaging mechanism is provided on the support, which cable-engaging mechanism engages a cable and defines a generally vertical cable segment and a generally horizontal cable segment in the cable. A first cable-gripping element and a second cable-gripping element on the support alternately and repeatedly grip and release the vertical cable segment of the cable. At least one of the cable-gripping elements is adapted for gripping and pulling the vertical cable segment of the cable along a vertical axis, such that the horizontal cable segment is pulled along a horizontal axis.

Description:
BACKGROUND OF THE INVENTION  
       CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application claims the benefit of copending U.S. Provisional Application Ser. No. 60/324,223, filed Sep. 24, 2001.  
         FIELD OF THE INVENTION  
         [0002]    This invention relates to apparatus for transmitting pulling motion from along a generally vertical axis to along a generally horizontal axis, and more particularly, to a vertical pull apparatus typically including a support which is positioned in a generally vertical position. A cable-engaging mechanism provided on the support engages a cable and defines a generally vertical cable segment and a generally horizontal cable segment in the cable. A first cable-gripping element and a second cable-gripping element on the support alternately and repeatedly grip and release the vertical cable segment of the cable. At least one of the cable-gripping elements is adapted for gripping and pulling the vertical cable segment of the cable, such that the horizontal cable segment is pulled horizontally.  
           [0003]    Underground water, gas, sewer and other utility pipes typically require replacement after an extended period of use, frequently due to corrosion or damage to the pipes. Usually, digging trenches to expose the damaged pipes for replacement is undesirable since this frequently requires destruction of streets, sidewalks, parking lots or lawns, which is unsightly and expensive. To avoid these problems, various techniques and apparatuses have been devised to destroy the pipe in need of replacement and draw a new pipe into place without having to excavate trenches for the operation. Generally, the techniques involve excavating the ground at both ends of the pipe to be replaced and positioning a hydraulic pulling device of selected design in one of the excavations and a cutting tool at the opposite end of the pipe in the other excavation. A cable is extended from the pulling device, through the pipe and attached to the cutting tool at the opposite end of the pipe. As the hydraulic pulling device is operated to pull the cutting tool against the pipe, a pneumatic hammer may be used to repeatedly strike the cutting tool against the pipe, and the combined pulling action of the pulling device and striking action of the hammer on the cutting tool causes the tool to migrate and progressively cut and burst the pipe along the entire length of the pipe. A replacement pipe is typically attached to the cutting tool such that the replacement pipe is drawn into position behind the cutting tool as the cutting tool bursts the old pipe. Under circumstances in which the hydraulic pulling device must be placed in a manhole at one end of the pipe, the narrow confines of the manhole render difficult adequate positioning of the hydraulic pulling device for the pipe bursting and replacing operation.  
           [0004]    A variety of devices are known in the art for transmitting a vertical or angled pulling motion into a horizontal pulling motion. Typical of these are the devices detailed in U.S. Pat. Nos. 4,318,835; 4,457,647; 4,685,831; 5,173,009; 5,192,165; 5,302,053; 5,328,297; 5,403,122; 5,642,912; 5,709,503; 6,109,832; and 6,244,783.  
           [0005]    Devices of various design are known in the art for bursting or re-rounding underground pipes. Patents of interest in this regard include U.S. Pat. Nos. 4,457,647; 4,634,313; 5,173,009; 5,192,165; 5,205,671; 5,302,053; 5,328,297; 5,403,122; 5,642,912; 5,709,503; 5,782,311; 5,785,458; 6,092,553; 6,109,832; 6,129,486; and 6,244,783.  
           [0006]    An object of the present invention is to provide a vertical pull apparatus for transmitting a generally vertical pulling motion into a generally horizontal pulling motion.  
           [0007]    Another object of this invention is to provide a vertical pull apparatus which is capable of a variety of applications.  
           [0008]    Still another object of this invention is to provide a vertical pull apparatus including a support for positioning in a generally vertical position; a cable-engaging mechanism provided on the support; a cable engaging the cable-engaging mechanism such that the cable-engaging mechanism defines a generally vertical cable segment and a generally horizontal cable segment in the cable; and first and second cable-gripping elements provided on the support for repeatedly and alternatively engaging the vertical cable segment of the cable, wherein at least one of the cable-gripping elements grips and pulls the vertical cable segment to pull the horizontal cable segment of the cable along a horizontal axis.  
         SUMMARY OF THE INVENTION  
         [0009]    These and other objects of the invention are provided in a vertical pull apparatus for converting a vertical pulling action to a horizontal pulling action, which vertical pull apparatus typically includes a support for positioning in a generally vertical position. A cable-engaging mechanism is provided on the support, which cable-engaging mechanism engages a cable and defines a generally vertical cable segment and a generally horizontal cable segment in the cable. A first cable-gripping element and a second cable-gripping element on the support alternately and repeatedly grip and release the vertical cable segment of the cable. At least one of the cable-gripping elements is adapted for gripping and pulling the vertical cable segment of the cable along a vertical axis, such that the horizontal cable segment is pulled along a horizontal axis. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The invention will be better understood by reference to the accompanying drawings, wherein:  
         [0011]    [0011]FIG. 1 is a perspective view of an illustrative embodiment of the vertical pull apparatus of this invention, in a typical application of the invention;  
         [0012]    [0012]FIG. 2 is a perspective view, partially in section, of the vertical pull apparatus, with an upper cable-gripping element and a lower cable-gripping element receiving a cable (partially in section);  
         [0013]    [0013]FIG. 3 is a front view, partially in section, of the vertical pull apparatus, with the upper cable-gripping element in the cable-releasing configuration and the lower cable-gripping element in the cable-gripping configuration, preparatory to pulling the cable;  
         [0014]    [0014]FIG. 4 is a longitudinal sectional view, taken along section lines  4 - 4  in FIG. 3, of the vertical pull apparatus, with the upper cable-gripping element in the cable-gripping configuration and the lower cable-gripping element in the cable-releasing configuration prior to repositioning of the lower cable-gripping element after pulling the cable;  
         [0015]    [0015]FIG. 5 is a transverse sectional view, taken along section lines  5 - 5  in FIG. 3, of the vertical pull apparatus; and  
         [0016]    [0016]FIG. 6 is an exploded, perspective view, partially in section, of the vertical pull apparatus. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    Referring initially to FIGS.  2 - 6  of the drawings, an illustrative embodiment of the vertical pull apparatus of this invention is generally illustrated by reference numeral  1 . The vertical pull apparatus  1  typically includes an elongated, vertical piling  2 , typically fitted with multiple, spaced-apart piling bolt openings  3 , as particularly illustrated in FIG. 6. The elongated power pole base  6  of a power pole  5  slidably receives the piling  2  and can be mounted at a selected height on the piling  2  by extending a piling bolt  4  through a pair of registering base openings  6   a  in the power pole base  6  and through a selected registering piling bolt opening  3  in the piling  2 , and threading a nut  4   a  on the piling bolt  4 . A cable gripping element bracket  19 , having a bracket opening  19   a , is provided on the front surface of the power pole base  6  adjacent to the upper end thereof. The bracket opening  19   a  receives an upper cable-gripping element  20 , typical of which is detailed in my U.S. Pat. No. 6,129,486 and includes a gripping element opening  21  for purposes hereinafter described. A pair of parallel side flanges  7  typically further extends from the front surface of the power pole base  6 , beneath the cable gripping element bracket  19 , and a pair of vertically-spaced cylinder mount brackets  9  each spans the side flanges  7  for purposes hereinafter described. A pair of bottom flanges  8  extends from the respective side flanges  7  on the power pole base  6 , typically at welds  7   a , and the bottom flanges  8  angle downwardly toward each other. The bottom ends of the bottom flanges  8  are fitted with respective sheave mount plates  15 , disposed in parallel, facing relationship to each other. The sheave mount plates  15  may be reinforced on the power pole base  6  by means of multiple mount plate gussets  17 . Registering mount plate openings  16  extend through the respective sheave mount plates  15  and receive a sheave mount shaft  12 , which further extends through a central sheave opening  11   a  provided in a sheave  11  to rotatably mount the sheave  11  between the sheave mount plates  15 , for purposes hereinafter described. The sheave mount shaft  12  is secured in the mount plate openings  16  of the sheave mount plates  15 , typically by means of a pair of mount pins  13 , in conventional fashion.  
         [0018]    As further illustrated in FIG. 6, a hydraulic cylinder  24  is mounted on the cylinder mount brackets  9 , between the side flanges  7  of the power pole  5 , typically by means of multiple cylinder mount bolts  10  extended through respective bracket bolt openings  9   a  provided in each cylinder mount bracket  9  and threaded into respective registering cylinder bolt openings  24   a , provided in a corresponding end of the hydraulic cylinder  24 . The hydraulic cylinder  24  is fitted with a pair of hydraulic lines  28  for connection to a hydraulic pump and supply mechanism (not illustrated). A piston  25 , traversed by a piston cable bore or opening  27 , is extendible from and retractable in the hydraulic cylinder  24  by operation of hydraulic fluid flow through the hydraulic lines  28  and hydraulic cylinder  24 , in conventional fashion. A lower cable-gripping element  22 , typically as detailed in my U.S. Pat. No. 6,129,486 and typically similar in design to the upper cable-gripping element  20 , is provided on the extending end of the piston  25 . The lower cable-gripping element  22  includes a gripping element opening  21 .  
         [0019]    Accordingly, in application of the vertical pull apparatus  1  as hereinafter described, a cable  30 , typically wound on a spool  34  (FIG. 1) which is typically rotatably mounted on a truck (not illustrated) or other support, for example, extends downwardly through the gripping element opening  21  of the upper cable-gripping element  20 , the gripping element opening  21  of the lower cable-gripping element  22 , the piston cable bore or opening  27  of the piston  25 , and the hydraulic cylinder  24 , respectively, and is extended around the sheave  11  to define a vertical cable segment  31  and a horizontal cable segment  32  in the cable  30 . Accordingly, in operation of the vertical pull apparatus  1  as hereinafter described, the piston  25  is initially disposed in the retracted position in the hydraulic cylinder  24 , as illustrated in FIG. 3, with the lower cable-gripping element  22  and the upper cable-gripping element  20  each lightly engaging the vertical cable segment  31  of the cable  30 . Upon initial extension of the piston  25  from the hydraulic cylinder  24 , the lower cable-gripping element  22  grips the cable  30 , and continued extension of the piston  25  from the hydraulic cylinder  24  causes the lower cable-gripping element  22  to pull the gripped cable  30  upwardly through the hydraulic cylinder  24  and the sheave  11  such that the horizontal cable segment  32  of the cable  30  is pulled horizontally through the sheave  11 , as indicated by the arrows in FIG. 4. Simultaneously, the upwardly-moving cable  30  initially moves the upper cable-gripping element  20  to an open, non-engaging conformation with respect to the cable  30 , and the cable  30  thus freely extends upwardly through the upper cable-gripping element  20  and is wound on the spool  34  throughout full extension of the piston  25  from the hydraulic cylinder  24 . After the full throw of the piston  25  from the hydraulic cylinder  24  has been reached and the lower cable-gripping element  22  is in the uppermost position illustrated in FIG. 4, the piston  25  is retracted into the hydraulic cylinder  24 , and the lower cable-gripping element  22  releases the cable  30  and returns to the lowermost position illustrated in FIG. 3. Simultaneously, the upper cable-gripping element  20  grips the cable  30  and prevents inadvertent downward slippage of the cable  30  through the upper cable-gripping element  20  and the lower cable-gripping element  22  until the lower cable-gripping element  22  returns to the lowermost position of FIG. 3 preparatory to a second pulling action on the cable  30 . At that point, the piston  25  is again extended from the hydraulic cylinder  24  and the upper cable-gripping element  20  releases the cable  30  as the lower cable-gripping element  22  grips and pulls the cable  30  upwardly through the hydraulic cylinder  24  and sheave  11 .  
         [0020]    Referring next to FIG. 1 and again to FIGS. 3 and 4 of the drawings, in typical application the vertical pull apparatus  1  is suitably adapted for bursting and replacing a horizontal subterranean gas, water or sewer conduit  40  which communicates with a manhole  39  (FIG. 1) or a narrow excavation (not illustrated) made for the purpose. Accordingly, an opening  41  is made in the concrete bottom of the manhole  39 , typically as far away from the conduit  40  as possible, and the bottom end of the piling  2  of the vertical pull apparatus  1  is inserted through the opening  41  and into the underlying ground beneath the manhole  39  to secure the piling  2  and the power pole  5  in a generally vertical position in the manhole  39 , as illustrated in FIG. 1, with the piling  2  typically extending upwardly through the manhole opening. The hydraulic lines  28 , attached to an appropriate hydraulic fluid pump and supply mechanism (not illustrated), are connected to the hydraulic cylinder  24 . After the cable  30  is extended through the conduit  40 , around the sheave  11 , through the hydraulic cylinder  24  and the piston  25 , and through the lower cable-gripping element  22  and the upper cable-gripping element  20  of the vertical pull apparatus  1 , a pipe bursting head  36 , which may be conventional, is attached to the horizontal segment  32  of the cable  30  through an excavation (not illustrated) or a second manhole (not illustrated) at the end of the conduit  40  opposite the manhole  39 . During subsequent operation of the vertical pull apparatus  1  by acutation of the hydraulic cylinder  24  as heretofore described, the horizontal cable segment  32  is incrementally pulled horizontally through the sheave  11  and the pipe bursting head  36  is shown horizontally against the conduit  40  to progressively migrate and burst the conduit  40  along its length. Simultaneously, a replacement conduit  43 , attached to the pipe bursting head  36 , is typically drawn into place behind the conduit  40  as the conduit  40  is burst. At the end of the pipe bursting and replacing operation, the pipe bursting head  36  is removed from the replacement pipe  43  in the manhole  39  and the vertical pull apparatus  1  is lifted from the manhole  39 .  
         [0021]    It will be appreciated by those skilled in the art that the vertical pull apparatus of this invention is suitably adapted for a variety of applications in which it is desired to transmit a vertical pulling motion into a horizontal pulling motion, particularly under circumstances in which limited space is available for accommodating the pulling equipment, such as in the bursting and replacement of sewer, water or gas lines. The vertical pull apparatus can be anchored in an open manhole, pit or excavation or on the ground for a variety of pulling applications, including but not limited to pipe-bursting and replacing, and is capable of use with any type of pipe-bursting equipment. Referring again to FIG. 1, in an alternative, dual-cylinder embodiment (not illustrated) of the vertical pull apparatus  1 , the upper cable-gripping element  20 , rather than being stationarily mounted on a cable gripping element bracket  19  as heretofore described, can be fitted on a piston  25  (FIG. 4) extendible from a hydraulic cylinder  24  in the same manner as heretofore described with respect to the lower cable-gripping element  22 , for alternately engaging and pulling the vertical cable segment  31  of the cable  30  in conjunction with the piston-mounted lower cable-gripping element  22 . In this dual-cylinder embodiment, the vertical pull apparatus has continuous pull capacity for loads limited only by the size and strength of the cable  30 . The construction and operation of the upper cable-gripping element  20  and the lower cable-gripping element  22  is described in U.S. Pat. No. 6,129,486, and each can be constructed in various sizes according to the diameter of the cable  30 .  
         [0022]    While the preferred embodiments of the invention have been described above, it will be recognized and understood that various modifications can be made in the invention and the appended claims are intended to cover all such modifications which may fall within the spirit and scope of the invention.