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TECHNICAL FIELD  
       [0001]     The present invention relates to a rotational drive apparatus for screw pilings and particularly to an apparatus which is transportable and which imparts a rotational drive to a coupling secured to the shaft of a piling. The apparatus is immobilized by a user person by the use of an elongated rod secured to the housing of the apparatus.  
       BACKGROUND ART  
       [0002]     Screw pilings are known which comprise a shaft having a helix secured at a lower end thereof whereby to drive the piling into the ground when the shaft thereof is rotated in a clockwise direction. To impart a rotational drive to such shafts, heavy machinery is used whereby to attach a rotational drive to the top end of the shaft of the piling. An example of this system is described in U.S. Pat. No. 5,066,168. A disadvantage of such system is that the apparatus is large, is expensive to use and its use is restricted to open space areas. It cannot be utilized in areas where there is no access provided for this heavy machinery.  
         [0003]     U.S. Pat. No. 5,707,180 discloses another apparatus wherein the piling is rotated manually. However, in hard ground surfaces this requires a lot of force by the user and accordingly the use of such screw pilings is restricted to loose soil. Another disadvantage of known screw piling systems is that they require at least three people to operate and it is therefore labour intensive. When a motor is secured to the top of the piling to rotate it, one person is required to stabilize the motor. Another person is necessary to maintain the piling substantially vertically and a third person is required whereby to operate the motor as such pilings are very unstable as they begin to penetrate within the ground surface. These systems are also hazardous to the operators. The installation can also be time-consuming as well as labour intensive and therefore this method is very costly. Known devices are also not ergonomically designed and are bulky and heavy, a further reason why they are labour intensive and difficult to use in remote hard-to-reach areas.  
       SUMMARY OF INVENTION  
       [0004]     It is a feature of the present invention to provide a rotational drive apparatus for screw pilings which substantially overcomes the above disadvantages of the known prior art.  
         [0005]     Another feature of the present invention is to provide a rotational drive apparatus which is adapted for use in location with difficult access such as in bushes or backyards of residential area or in areas remote from roads.  
         [0006]     Another feature of the present invention is to provide a rotational drive apparatus for screw pilings and which can be utilized by only two operating persons and which does not require any heavy machinery which may be damaging to the environment or to a grassed-in area such as in residential areas.  
         [0007]     Another feature of the present invention is to provide a rotation drive apparatus for screw pilings and which is capable of imparting a rotational drive to such pilings in shallow bodies of water and in the interior of structures where a support piling needs to be installed.  
         [0008]     Another feature of the present invention is to provide a rotational drive apparatus for screw pilings which is lightweight and easily transportable and which provides sufficient torque to drive the pilings within the earth.  
         [0009]     Another feature of the present invention is to provide a drive apparatus for screw pilings which may be used in ecological areas to drive pilings into a swamp area while preserving the environment as the apparatus does not use toxic matter and is non-polluting.  
         [0010]     Another feature of the present invention is that the rotational drive apparatus can be used in areas with limited headroom for the reason that the drive apparatus is not connected at the top of the pilings and can be adapted to shorter, interconnectable, piling sections.  
         [0011]     Another feature of the present invention is to provide a rotational drive apparatus for screw pilings and wherein the apparatus can be used in harsh climatic conditions such as for driving pilings through snow covered earth.  
         [0012]     Another feature of the present invention is to provide a rotational drive apparatus for screw pilings and which apparatus is economical to produce thereby reducing the cost of installation of such pilings and wherein the drive is automatically controlled by a user person and further wherein the drive is adapted to install screw pilings within a ground surface or remove them therefrom.  
         [0013]     According to the above features, from a broad aspect, the present invention provides a rotational drive apparatus for earth screw pilings. The apparatus comprises a housing having a cylindrical pipe coupling adapted to receive a shaft of a screw piling therethrough. Detachable connecting means are provided for securing the coupling to the shaft at different positions along the shaft. A rotational drive is provided within the housing for imparting rotation to the coupling. Immobilizing means is provided to maintain the housing substantially stationary whereby to permit the rotational drive to transmit a rotational drive force to the coupling.  
         [0014]     According to a still further broad aspect of the present invention there is provided in combination, an earth screw piling having a shaft with a drive helix at a lower end thereof, and a rotational drive apparatus. The shaft has a plurality of spaced-apart holes therealong and extending diametrically across the shaft. The rotational drive apparatus has a cylindrical pipe coupling secured to a selected one of the holes by a pin connector. Means is provided to impart a rotational drive to the shaft coupling for rotating the shaft. Means is provided to immobilize the pipe coupling relative to the shaft when the shaft is rotated. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0015]     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:  
         [0016]      FIG. 1  is a perspective view showing the operation of the rotational drive apparatus for driving a screw piling within a ground surface;  
         [0017]      FIG. 2  is a perspective view showing the rotational drive apparatus connected to the shaft of a screw piling;  
         [0018]      FIG. 3  is a perspective view showing the construction of the elongated immobilizing rod;  
         [0019]      FIG. 4  is a cross-section view through the housing showing the construction of the rotational drive and the coupling of the cylindrical pipe coupling to the shaft of a piling;  
         [0020]      FIG. 5  is a cross-sectional top view illustrating the construction of the rotational drive; and  
         [0021]      FIG. 6  is an exploded view of the drive housing and its associated parts. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0022]     Referring now to the drawings there will be described the rotational drive apparatus of the present invention. As shown in  FIG. 1 , the rotational drive apparatus  10  is secured along a shaft  11  of a screw piling  12  which is provided with a drive helix  13  secured at a lower end  14  thereof. The shaft  11  is a hollow shaft as shown in  FIG. 2  and is provided with a plurality of spaced-apart holes  15  therealong. The drive apparatus comprises a housing  16  in which is located a drive connection and a coupling to impart rotation to the shaft  11  of the screw piling  12 . A drive motor  17  is the power source for the drive.  
         [0023]     With reference to  FIGS. 4, 5  and  6 , there is illustrated the construction of the rotational drive component and the shaft coupling. A cylindrical pipe coupling  20  is herein illustrated secured vertically with respect to the horizontal plane  21  of the housing  16 . The pipe coupling  20  is secured to the bottom end  22  of a rotational guide sleeve  23  which is dimensioned to receive the shaft  11  of the screw piling in close sliding fit therethrough. The pipe coupling  20  is of substantially like diameter. As hereinshown the coupling and the guide sleeve are of circular cross-section but these can have different cross-sections to match the cross-section of the shaft  11  of the pile to which the-housing is to be secured to.  
         [0024]     The drive motor  17  is immovably secured to the top wall  16 ′ of the housing  16  and has a drive shaft  24  extending within the housing and to which is coupled a drive ring gear  25 . A driven ring gear  26  is immovably secured to the rotational guide sleeve  23  to which a cylindrical pipe coupling  20  is secured by means of the securing bolts  27 . An endless chain  28  interconnects the drive gear  25  to the driven ring gear  26  to impart rotation thereto and to the pipe coupling  20 .  
         [0025]     In order to couple the cylindrical pipe coupling  20  to the shaft  11  of the screw piling, there is provided a removable lock pin  30 . As hereinshown, the cylindrical pipe coupling  20  is provided with diametrically aligned slots  31  projecting vertically from a lower edge  32  thereof with the lock pin being disposed across the slots  31  and through one pair of the diametrically aligned holes  15  of the shaft  11 . Accordingly, the shaft is thereby secured to the cylindrical pipe coupling and to the rotational guide sleeve  23 .  
         [0026]     In order to cause the cylindrical pipe coupling and the rotational guide sleeve to rotate the shaft  11 , it is necessary to immobilize the housing  16 . In order to do so, there is provided, as illustrated in FIGS.  1  to  3 , an elongated immobilizing rod  35 . This rod has an attaching end in the shape of a detachable connecting fork  36  which is secured to a connecting handle  37  secured to the housing  16 . The connecting handle provides ease of transportation of the housing. A detachable connecting pin  38  interlocks the elongated rod  35  to the handle  37  and accordingly the housing  16 , thereby means for immobilizing the housing during the operation of the rotational drive.  
         [0027]     Ideally, the elongated rod  35 , as shown in  FIG. 1 , is long enough to resist the torque of the drive to permit the drive motor  17  to rotate the coupling and provide the necessary torque thereto to drive the piling into the ground. The user person  39  provides this immobilization of the rod  35  and the housing by holding the rod  35  at its far end  35 ′.  
         [0028]     The hydraulic motor  17  as herein-illustrated is a hydraulic drive motor and pressurized hydraulic fluid is supplied thereto through a pair of hoses  40  which are secured to a hydraulic pump  41  through an operable valve  42 , as schematically illustrated in  FIG. 1 . The pressurized reservoir is part of a transportable gas operated hydraulic unit  43 . A remote control cable  44  provided with a switching device  45 , permits the operator  39  to operate the valve and hence the direction of rotation of the hydraulic motor  17  whereby to screw the piling  12  into the ground or to remove it therefrom. The motor can be rotated in either direction for insertion or removal of the pilings.  
         [0029]     As also shown in  FIG. 1 , the displaceable coupling permits the user persons  39  and  39 ′ to operate the apparatus at a comfortable height, usually between 1 to 4 feet. As the piling screws into the ground and the housing  16  descends closer to the ground, it is only necessary to disconnect the pipe coupling  20  by the removal of the lock pin  30  and to reconnect the housing to the next pair of diametrical holes thereabove. This can be done by a second user person  39 ′ without any assistance due to the compact size and lightweight of the rotational drive apparatus  10 .  
         [0030]     The earth screw piling as shown in  FIG. 1  is usually one which is approximately  10  feet in length but the present invention is not intended to be restricted to such pilings. It is foreseeable that the piling could be of a considerably longer length or the shaft of the piling could be constructed in interconnectable sections. It can be appreciated that the ease of installing the housing  16  to the piling is simple and effortless. With the piling on the ground the shaft of the housing is simply slid through the guide sleeve and pipe coupling which is transversely disposed relative to the housing. The coupling  20 , or adaptor, is interchangeable to adapt the piles having different diameter and cross-sectional shapes, such as a square cross-section.  
         [0031]      FIG. 6  shows all of the component parts assembly of the rotational drive associated with the housing  11  and they consist of a housing top section  50  and a bottom section  51 . Sealing rings  52  and  53  provide the necessary seal to the interior of the housing. A washer  54  is provided at the top end thereof. A pair of roller bearings  55  are secured about the rotational guide sleeve  23  as clearly illustrated in  FIG. 4  and located within a bearing housing  46 . A sealing ring  47  is also located under the bearing assembly. A chain tensioner  48  is also secured to the inner wall of the top section  50  of the housing  11  to apply tension on the drive chain  28 .  
         [0032]     The hydraulic unit  43  as herein-illustrated is a two-cylinder  40  horse power gas-operated unit. The reservoir has a capacity of 9.7 liters and the unit weighs about 150 lbs. but is supported on wheels thereby making it easily displaceable. The torquing pressure delivered to the motor is at approximately 140 bar. It is also pointed out that the rotational drive apparatus may be constructed with different types of motors or two motors and of different size whereby to handle earth screw pilings of different sizes and lengths.  
         [0033]     It is therefore, within the ambit of the present invention, to cover any obvious modifications of the preferred example of the rotational drive apparatus of the present invention as described herein. However, this is provided such modifications fall within the scope of the appended claims.

Summary:
A rotational drive apparatus for screw pilings is described. The apparatus comprises a housing having a cylindrical pipe coupling adapted to receive a shaft of a screw piling therethrough. A detachable connecting element secures the coupling to the shaft at different positions along the shaft. A rotational drive is provided within the housing for imparting rotation to the coupling. An elongated rod is secured to the housing and is held by a user person whereby to immobilize the housing wherein to permit the rotational drive to transmit a drive force to the coupling to rotate the shaft of a screw piling.