Patent Publication Number: US-6217260-B1

Title: Downhole reamer with double acting dual piston cylinder

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to an apparatus for grouting of reinforced concrete piles for buildings, bridges or various foundations, in particular, to a hydraulic expanding apparatus for the construction of piles of bridges, buildings, protection slopes, and high-pressure anchor struts, etc. 
     BACKGROUND OF THE INVENTION 
     As disclosed in Chinese Patent No. CN 2218768Y, the present expanding apparatus, such as a hydraulic aviate former for piles with multi-branch bearing plates, is a multi-branch bearing plate pile machine designed to increase its bearing capacity and tensile strength. With this machine, construction of a pile is completed by drilling a hole, expanding the hole, and pouring concrete into the holes. The multi-branch bearing plate hole expanding apparatus is a special equipment for forming the side cavities of the pile holes to be fulfilled with concrete, which is suitable not only for poured piles, but also for anchor struts. It is proven that the pile so built has the features of increased load bearing capacity and reduced amount of concrete poured into. However, the extended tube of this expanding apparatus is rigidly coupled by connecting steel pipes one segment after another and is lifted and dropped unto a determined depth of a hole by a crane to perform an expanding operation. After one expanding operation is completed, the bow pressing arm is retracted and revolved to the next position with the aid of a thinner steel tube extending through a hole on the steel arm and expanding operation starts again. 
     To complete expanding of an entire cavity, the steel arms have to be revolved 8-9 times. The reason to have a rigid coupling of steel pipes is to achieve these functions: 
     (a) torque transmission, 
     (b) tension transfer, and 
     (c) measurement of the depth of the working device in a hole. 
     If the expanding operation takes place at the bottom of a hole of 40 m-50 m deep, an extended steel tube has a diameter of 280 mm, a wall thickness of 14 mm, and a length of 40 m-50 m and the working device has to be lowered down into the hole. The extended steel tube weighs to tens of tons, which makes vertical movement of the long extended tube difficult, resulting in labor and time wasting. Furthermore, when an extended tube is in a hole at tens of meters deep, there is likely offset vertically, which may cause the steel tube stuck in the hole. Especially when expanding, a pressure force of hundreds of tons is applied to both sides of the hole, so the steel tube inclines towards one direction if the angle of the pressure force is applied offset, resulting in a side force increased by tens of times. As a result, the connecting bolt and shaft pin may be broken so that the expanding device may fall down into the hole. In addition, the prior art apparatus may not accurately measure the depth the tube drops down and thus, the layer underground can not be located accurately. This inaccurate location leads to error on the load bearing capacity and creates poor piles. 
     Besides, there is an outer tube outside the bow pressing arm, which not only increases the weight of the apparatus, but also brings soil with it while the bow pressing arm is retracted. It is even worse when the expanding operation is performed at a layer of sand and stones since stones brought into the tube may stick the bow pressing arm from being retracted. In this case, it is impossible to lift up the apparatus from the hole as the bow pressing arm cannot be retracted to its normal position. In addition, prior art expanding apparatus neither detects the status of the soil being expanded, nor tests the expanding operation. Therefore, concrete pouring processing in construction of a pile has to be stopped once collapse happens, thus, what is needed is an extending apparatus that may be smoothly moved in a hole to complete expanding process. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide an extending apparatus with flexible coupling for tension transfer. Preferably, a flexible steel rope is used as coupling means. Also, an automatic hydraulic revolving device is provided for transfer of torque; a depth measuring device and a drag cleaning device at the bottom of the hydraulic cylinder are provided to clean drag; and an expanding device with multi-arms at the same circular cross-section is provided to increase the stability of the operation and for central positioning. 
     Another objective of the present invention is to measure pressure values and recognize the layer of soil in expanding process. With aid of a displacement sensor, pressure value of each arm, pressed angles, and values of the expanding device revolving angle are accurately detected. 
     To implement the present invention, the fully intelligent multi-functional expanding apparatus includes a hydraulic expanding device, an automatically controlled hydraulic center, and a measuring system. The hydraulic expanding device includes a hydraulic positioning device, a hydraulic revolving device, a unidirectional pulling type bi-directional cylinder, and an expanding arms, which are rigidly connected one by one. 
     The hydraulic positioning device has a shaft pin connected to a coupler, a steel rope connected to the shaft pin, and an external tube connected to the coupler. The revolving positioning device is fixed on the bottom of the positioning device by an external positioning tube, a hydraulic positioning block, and a central positioning block; wherein three hydraulic cylinders are fixed on three hydraulic positioning blocks respectively, and a ladder-shaped block is coupled to the piston rod of each hydraulic cylinder. When the cylinders retract, all the ladder-shaped blocks contact on external wall of the tube that has three holes through the tube wall to allow the three piston rods to move back and forth. Six hydraulic oil hoses of three hydraulic cylinders are connected to two main hydraulic pipes in parallel. 
     The hydraulic revolving device works with its external tube fixed to the bottom of the external position tube and a central positioning block connected to a steam spring. Positioned by a nut, the steam spring is coupled to the external tube wall of the cylinder of the revolving device through the shaft pin. The cylinder is coupled to a pressure stop dog by a revolving pin. A displacement sensor and the hydraulic oil hoses are fixed on the cylinder. The hydraulic oil hoses are extended through the tube wall. With the pressure stop dog and pressure shaft locked by the coupling shaft with a nut, revolution is performed with reciprocating movement of the cylinder. 
     The other way of operation of the hydraulic revolving device is with its external tube rigidly coupled to the positioning device, the cylinder positioning block coupled to the external tube wall, the cylinder coupled to the external tube and the cylinder positioning block, the cylinder piston rod connection rack engaged with a gear that is fastened on the external tube wall and shaft holding block with a first bevel gear by means of a shaft so as to engage with a second bevel gear coupled to a central shaft. With a pressure stop dog, the pressure bearing is revolved. 
     The unidirectional pulling type bi-directional cylinder has its upper lid of the bi-directional cylinder coupled to the central shaft. The bi-directional cylinder includes a cylinder wall, a piston pulling rod, a piston push sleeve, and hydraulic hoses. The piston pulling rod moves downward along the cylinder inside wall while the piston push sleeve allows a reciprocating movement along cylinder inner wall and the external wall of the piston pulling rod. With the control of hydraulic oil, the piston push sleeve is connected to a multi-arm connecting block with a revolving pin. The multi-arm connecting block is coupled to 3-4 bow pressing arms with the shaft pin and the bow pressing arms and a bottom support are rigidly coupled to the piston pulling rod. Displacement sensors are respectively fitted on the multi-arm connecting block and the piston pulling rod. Pressure sensors and the displacement sensors are connected to a single-chip processor fitted on the multi-arm connecting block. 
     The hydraulic expanding head is connected to the crane by a steel rope and connected with automatic hydraulic control center through multi-channel tube and the control circuit. The hydraulic control center includes a hydraulic plunger pump connected to a control keyboard, a printer, a display, a central processing display, a notebook respectively. The hydraulic control center is installed on a truck that has a diesel plunger pump to be able to switch with an electric plunger pump for operation. 
     The depth measuring system has its support plate connected to two shafts which are mounted on two wheels. These two wheels are connected to the steel rope of the crane with the support frame of the depth measuring system fixed on ground. One of the two wheels is slidible along a slot in the support plate. Lateral movement of the shaft is controlled by a spring which is connected to support plate and the shaft. At the other wheel, a light block device is mounted. A photo-electro interrupter is fitted on the support plate. These two wheels sandwich the steel rope when pulling one of the wheels backward, so as to turn the movement of the steel rope into rotation of the wheels. With one turn completed, the photo-electro interrupter is interrupted once by the light block device. The photo-electro interrupter counts the times of the interruption so that the depth that the hydraulic expanding head locates in a hole can be measured. The crane, expanding apparatus, and truck can be combined into one vehicle, i.e. putting the crane, expanding apparatus, depth measuring system, automatic control hydraulic center onto one truck for easy movement. 
     The positive effects of the present invention are as below: 
     (1) With the aid of the flexible steel rope, the lever force due to rigid connection is released, the steel tube segments for extended length of the hydraulic expanding head in a hole is reduced, and the total weight of the extended steel tube is lessened. Accordingly, the expanding apparatus in accordance with the present invention may be for wider applications. 
     (2) As the hydraulic automatic revolving device is adapted for transfer of torque, three cylinders are used for self-positioning of the revolving. Fitted 120° apart between any two of them on a horizontal, the ladder-shaped blocks are pushed into the soil on the wall of the hole when the hydraulic cylinders stretch out, positioning its center of the hydraulic expanding head body as the self-positioning is performed with the three cylinders&#39; operation. 
     (3) The use of the bi-directional cylinder expanding device eliminates up or down movement of the equipment during the positioning operation, hence the soil drop to the bottom of the hole is greatly reduced. Compared to the prior art expanding apparatus, where the three points (referring to FIG. 1) on the three connecting shafts of its three bow pressing arms moved during operation as described below: 
     X and Y represent the horizontal or vertical directions of the force, arrows following X and Y indicate the direction of movements.          Point A      {           X   =   0               Y   =   ↓                                            Point B                     {             X   =   →               Y   =   ↓                            Point C                     {           X   =   0               Y   =   0                                 
     Such a movement causes a lot of dregs on the bottom of the hole. When point B just comes into contact with the soil, the hydraulic expanding head penetrates into soil not much, so the wall of the hole can hardly provide any support. The movement in Y direction at point B applies the weight of the hydraulic expanding head to point B, resulting in soil slide into the bottom as dregs. While the hydraulic expanding head is lowered to deep in the hole, it will be raised due to downwards movement of point B, for example, a hydraulic expanding head of φ600 mm goes up 30-40 cm with each expanding operation. If the left and right points become unbalanced during expanding operation, an offset from its raising direction, which in turn results in the hydraulic expanding head to be in contact with the hole wall to cause accident. Accordingly, movements of the three connecting shafts in accordance with the present invention are defined as following:          Point A      {           X   =   0               Y   =   ↓                                            Point B                     {             X   =   →               Y   =   0                            Point C                     {           X   =   0               Y   =   ↓                                 
     |YA|=|YC| means these two sectors are of identical absolute values, but in opposite directions. Such shaft B only moves along X direction i.e. the expanding direction, the hydraulic expanding head completes expanding operation with point B as a fixed horizontal position without vertical movement, reducing drastically the amount of dregs down to the bottom of the hole. The piston sleeve and piston rod are pushed out at identical operation pressure and the working areas of the piston sleeve and piston rod are the same, so the force of both when pushing out is same as each other. On the other hand, when the cylinder retracts, the upper and lower cylinders are connected to each other with identical operation pressure but different working areas, resulting in different retracting speeds of them. However, the expanding apparatus does no work when retracting so that expanding operation may be performed smoothly. 
     The expanding apparatus in accordance with the present invention replaces the cylinder long rod pressure, i.e. the piston rod is compressed when doing work, by cylinder piston long rod pulling i.e. the piston rod is pulled when doing work, which greatly improves the effect of side-direction force on the piston rod, ensuring Point B to move only along X direction and less or no dropping of soil during expanding operation. 
     (4) As the expanding apparatus in accordance with the invention is designed an uni-directional pulling cylinder which clears up dregs and therefore greatly increases the efficiency to construct piles. Clear-up of dregs at the bottom of a hole is a most difficult problem prior art encountered. If the dregs can not be cleared up, the bearing capacity at the end of a pile may be affected seriously. In order to solve this problem, a pulling cylinder hydraulic expanding head in accordance with the present invention is designed to define movement of the three connecting shafts of the bow pressing arms as below:          Point A      {           X   =   0               Y   =   0                                            Point B                     {             X   =   →               Y   =   ↓                            Point C                     {           X   =   0               Y   =   ↓                                 
     As point B moves in Y direction, which enables the hydraulic expanding head has a Y↓ movement. In case of a cylinder of φ400 with a 200-300 tons of expanding force, the hydraulic expanding head expands downwards while expanding operation is performing on two sides. With the body of the hydraulic expanding head moving down by 30-40 cm, the dregs of soil at the bottom of the hole is compressed into solid status. It is proven that the bearing capacity of compressed soil is increased by 30%. This solved the dregs problem in operation of branch plate cavity expanding operation. 
     (5) As the hydraulic expanding head in accordance with the present invention eliminates the external tube, the multi-arm expanding head is prevented from interference of the external tube within identical circular cross section. The multi-arm hydraulic expanding head adopts inner positioning guide to replace the external positioning guide of prior art, which saves space greatly, causes drastic weight reduction, enables multi-arm expanding each time in identical circular cross section. i.e. expanding operation may be done once in an identical circular cross section with 3 arms, 4 arms, 6 arms, 8 arms, 12 arms, greatly enhancing efficiency, operation stability, and central positioning. 
     (6) The hydraulic expanding head in accordance with the present invention is automatically controlled with a pressure sensor installed by 0.618 of length on each bow pressing arm, so pressure values at any moment may be obtained during expanding operation. Pressure value that is varied with the time is amplified and converted into a digital signal by an A/D converter, and three curves are printed by an integraph and ΣF values are shown. Therefore, the pressure status of each arm reflects not only single force but also combined force to recognize soil layers for quality control during construction. 
     (7) With a displacement sensor and a single chip processor installed on the bow pressing arm, an overall model can be built up in a microprocessor during the operation, thus obtaining pressure value on each arm, value of pressed angle, value of revolving angle, and the depth of the expanding apparatus in the hole in real time, which can eventually give the load bearing capacity of each pile before it is poured, i.e. it is a test of the prospecting, also it is a solution in testing of the branch plate pile. For example, when an expanding operation is finished but the its quality is unknown, one more expanding operation can be carried out at the same position. The expanding operation is successful if the indication of the pressure meter does not change. Otherwise, the change of pressure value at an angle shows a collapse occurred there. When the power supply is off, a notebook PC may be used for data processing, enabling quality control of the construction and establishing a database for each pile for future design. 
     (8) With an automatic control hydraulic center and a diesel hydraulic station installed on a diesel truck, the hydraulic expanding head in accordance with the present invention can operate in fields using the diesel hydraulic station with insufficient power supply; otherwise, it can operate with electric hydraulic station to have the hydraulic expanding head in accordance with the present invention operate under various condition, especially in road and bridge construction. 
     These and other features and advantages of the present invention are apparent from the description below with reference to the following drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a section view of the hydraulic expanding head in accordance with the present invention; 
     FIG. 2 shows the coupling of the expanding apparatus in accordance with the present invention in operation; 
     FIG. 3 is a section view of a revolving positioning of the hydraulic expanding head in accordance with the present invention; 
     FIG. 4-1 is a section view of an automatic gear revolving device of the hydraulic expanding head in accordance with the present invention; 
     FIG. 4-2 is a top view of the hydraulic expanding head in accordance with the present invention; 
     FIG. 5 is a section view of a cylinder revolving device of the hydraulic expanding head in accordance with the present invention; 
     FIG. 6-1 is a section view of a three bow pressing arm device of the hydraulic expanding head in accordance with the present invention; 
     FIG. 6-2 a section view of a four bow pressing arm device of the hydraulic expanding head in accordance with the present invention; 
     FIG. 7 is an illustrational view showing the automatic control hydraulic center of the hydraulic expanding head in accordance with the present invention; 
     FIG. 8-1 is a front view of an electronic depth measuring system of the hydraulic expanding head in accordance with the present invention; and 
     FIG. 8-2 is a top view of the electronic depth measuring system of the hydraulic expanding head in accordance with the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A hydraulic expanding head of intelligent multi-functional hydraulic expanding apparatus in accordance with the present invention includes a coupling body  2 , a shaft pin  3 , an external tube  4 , a ladder-shaped block  5 , a hydraulic hose  6 , a hydraulic cylinder  7 , a positioning block  8 , and a central positioning block  9 , as shown in FIG.  1  and FIG. 3. A hook of a truck lifts up or down of the hydraulic expanding head through shaft pin  3 . During operation, hydraulic cylinder  7  pushes ladder-shaped block  5  into soil to locate the position while ladder-shaped block  5  is pulled to be in contaact with external tube  4  when hydraulic cylinder  7  retracts. 
     Referring to FIG. 5 that is B—B section of FIG. 1, an automatic hydraulic revolving device includes an external tube  24 , a nut  25 , a revolving pin  26 , a steam spring  27 , a coupling shaft  28 , a revolving push block  29 , a pin  30 , an oil hose  31 , a hydraulic cylinder  32 , a pressure stop dog  33 , a nut  34 , and a displacement sensor  49 . With cylinder  32  stretches, revolving push block  29  makes external wall  24  revolve. When cylinder  32  retracts, steam spring  27  pushes cylinder  32  to make revolving push block  29  move backwards along the internal wall of external tube  24  to the next slot, revolving push block  29  enters into the slot and cylinder  32  stretches again to start next cycle. This operation repeats with revolution of 30° after each cycle. A sensor  49  generates a signal when the revolution of 30° is finished to implement automatic control. 
     Alternatively, automatic hydraulic revolving device may be implemented as shown in FIGS. 4-1 and  4 - 2 . The automatic hydraulic revolving device includes an external tube  10 , a pressure bearing  11 , a coupling pressure stop dog  12 , a bearing support block  13 , a bearing  14 , a rack  15 , a cylinder positioning block  16 , a hydraulic cylinder  17 , an oil hose  18 , a gear axle  19 , a spur gear  20 , bevel gears  21  and  22 , and a coupling shaft  23 . Cylinder  17  drives rack  15  move up and down, which in turn drives spur gear  20  and bevel  22  rotated. The rotation of bevel  22  drives bevel  22  rotated, which then drive coupling shaft  23 . Finally, the linear movement of cylinder  17  is turned into vertical rotation of rack  15 . 
     Unidirectional pulling type bi-directional cylinder of hydraulic expanding head includes hoses  35  and  36 , a piston rod  37 , cylinder wall  38 , and a piston sleeve  39 . When oil is injected into the cylinder via hose  36 , piston rod  37  and piston sleeve  39  do work. As the working areas of piston rod  37  and piston sleeve  39  are the same, their displacements are of a same distance but in opposite directions. Piston rod  37  and piston sleeve  39  retract in the cylinder when oil is injected into it from hose  35 . The top and bottom of the cylinder are connected to perform a operation cycle of the bi-directional cylinder. 
     Unidirectional cylinder includes hoses  35  and  36 , a piston rod  37 , cylinder wall  38  without piston sleeve  39 . Piston rod  37  coordinates with cylinder wall  38  so that piston rod  37  moves upwards when oil is injected into the cylinder from hose  36  while it moves downwards when oil is injected into the cylinder from hose  35 . 
     Expanding arm of the hydraulic expanding head includes a multi-arm connecting block  40 , a bow pressing arm  41 , a shaft pin  42 , a bottom support  43 , a pressure sensor  46 , a displacement sensor  47 , and a micro-processor  48 . Connecting block  40  moves down with piston sleeve  39 . In the meantime bottom support  43  is brought upwards by piston rod  37 . In this way bow pressing arm  41  is driven to expand. In an opposite process, bow pressing arm  41  retracts. When connecting block  40  moves downwards, displacement sensor  47  measures the working angle of bow pressing arm  41  on the basis of the displacement of piston rod  37 . A signal is sent to micro-processor  48  for amplification and then, transferred to control center for further processing. Sensor  46  fitted on bow pressing arm  41  measures the pressure value of the soil applied onto the bow pressing arm  41  during operation and a signal so generated is sent to micro-processor  48  for amplification and then, transferred to the control center for further processing. 
     In accordance with one preferred embodiment of the present invention, multi-arm connecting block  40  outside piston rod  37  is connected to three bow pressing arm device  44  and bottom support  43 , as shown in FIG. 6-1. 
     Alternatively, FIG. 6-2 shows another preferred embodiment of multi-arm expanding device in which multi-arm connecting block  40  outside piston rod  37  is connected to four bow pressing arm device  44  and bottom support  43 . 
     Depth measuring system includes a photo-electro interrupter  50 , a light block device  51 , a drive wheel  52 , a holding plate  53 , a spring  54 , a wheel  55 , and a shaft  56 , as shown in FIGS. 8-1 and  8 - 2 . In operation, wheel  55  is pulled backwards until steel rope  66  is clamped between two wheels. The movement of steel rope  66  brings wheels  52  and  55  rotated and when the light block device  51  is turned to a position where the photo-electro interrupter  50  is blocked, a pulse signal is generated by photo-electro interrupter  50  to indicate that the steel rope completes a cycle distance so that the depth of a hole is measured accurately. 
     An automatic control hydraulic center  64  includes hoses  35  and  36 , a hydraulic plunger pump  58 , a control keyboard  49 , a printer  60 , a meter  61 , a microprocessor and display  62 , and a notebook computer  63 , as shown in FIG.  7 . All data from microprocessor, pressure sensor, angle displacement sensor, and plunger pump is processed in the automatic control hydraulic center  64 , which is based on in control of the operation of the expanding apparatus. Meanwhile, the data in all operation is recorded so as to display an overall three-dimensional model of the expanding apparatus in the microprocessor and display  62 . 
     The couplings of the expanding apparatus in accordance with the present invention in operation is shown in FIG.  2 . After a hole is drilled, crane  65  lifts hydraulic expanding head to lower it into the hole. The depth measuring system is fixed with a hose fastener  67  on the steel rope  66  and is lowered downwards into this hole slowly. When the depth measuring system reaches to a predetermined depth, automatic control hydraulic center  64  control the hydraulic expanding head to start to expand with expanding, retracting, revolving, and expanding of the bow pressing arms. This process repeats several times to form a branch plate cavity. Then the hydraulic expanding head is lowered to another predetermined depth and the operation is performed again to form another cavity. After the operation, the bow pressing arms are retracted and the hydraulic expanding head is lifted up by the crane. Followed processing is ire installation and concrete pouring to construct a branch plate pile. In the occasion of shortage of power, diesel plunger pump  68  is used, making the hydraulic expanding head is applied to wider range of operation conditions. 
     It will be understood that the previous descriptions and explanations are given by way of example, and that numerous changes in the combinations of elements and functions as well as changes in design may be made without departing from the spirit and scope of the invention as hereinafter claimed. These and other modifications to and variations upon the embodiments described above are provided for by the present invention, the scope of which is limited only by the following claims.