WO2008091051A1

WO2008091051A1 - Pipe coupling device

Info

Publication number: WO2008091051A1
Application number: PCT/KR2007/005248
Authority: WO
Inventors: Woon Ki Min
Original assignee: Woon Ki Min
Priority date: 2007-01-22
Filing date: 2007-10-24
Publication date: 2008-07-31
Also published as: KR200436084Y1

Abstract

The present invention relates to a pipe coupling device which couples pipes by a simple manipulation without deforming the pipes, and couples the pipes more firmly by fixing external and internal circumferences of the connecting pipes at the same time. A pipe coupling device which couples and fixes end parts of connecting pipes, the device comprising front and rear external coupling members which are shaped like a cylinder to insert end parts of the pipes thereinto and have manipulation holes drilled in an external circumference to face each other; an internal coupling member which has a flow hole formed in an internal part of a round bar-shaped body inserted into an internal part of the front and rear external coupling members in forward and backward directions to communicate with an internal hole of the pipes, and has gear installing grooves formed corresponding to the manipulation holes, respectively; a pair of fixing gear units which have an input gear installed in the gear installing grooves of the internal coupling member and an output gear rotatably installed in the internal coupling member to be engaged with the input gear; front and rear external fixing means which are formed in opposite sides of the internal coupling member to press and fix an external circumference of the pipes by moving outwardly when the fixing gear units rotate; front and rear internal fixing means which are formed in opposite sides of the internal coupling member to press and tightly contact the internal circumference of the pipes by moving outwardly when the fixing gear units rotate.

Description

Description PIPE COUPLING DEVICE

Technical Field

[1] Apparatuses and methods consistent with the present invention relate to a pipe coupling device, and more particularly, to a pipe coupling device which connects and fixes end parts of pipes in connecting the pipes and forming a pipe line. Background Art

[2] Generally, various equipment such as construction equipment and plant equipment have a pipe line through which a variety of fluids like water, fuel, material and the like flow.

[3] In the pipe line, pipes in predetermined length are installed in specific paths depending on configuration of the installation space and purposes. Here, opposite end parts of pipes are connected by welding, screw coupling, flange coupling and the like.

[4] The welding is commonly used in connecting pipes, but requires extra tools and skilled operators. Particularly, workers may be injured or fire may occur during the welding process, and the risks further increase in a space where flammable materials are present.

[5] The screw coupling is that an additional coupling device is coupled to screws after the screws are formed in opposite end parts of connecting pipes by a screw molding machine.

[6] As the screws should be formed in the end parts of the connecting pipes for the screw coupling, assembly time increases, and strength of the pipes may be weaker while being cut. Furthermore, the screw coupling may not be easily employed in pipes having large diameters.

[7] The flange coupling is that bolts are coupled after a flange is assembled to end parts of connecting pipes, and is widely used in connecting pipes having relatively large diameters without directly damaging the pipes. However, the flange is assembled to the pipes by a welding process, which brings about welding-related problems again.

[8] Thus, various types of pipe coupling devices have recently been developed and used to perform the pipe coupling operation more safely and conveniently. In this case too, however, end parts of the connecting pipes should have an additional coupling configuration such as screws and grooves to install the suggested pipe coupling devices, and the connected end parts of the pipes are damaged.

[9] As a prior art to perform an assembly process of end parts of pipes without damage,

Korean Patent No. 10-0537074 discloses a connecting structure for a pipe by which pipes can be connected with each other with sealing pads 38 and 39 and coupling sockets 40 and 41 without screws.

[10] However, as the sealing pads and coupling sockets are tightly fixed to only an external circumference of the pipes, adhesion is weak and the pipes are not firmly fixed. Also, since the coupling sockets are assembled by a coupling method, the assembly operation is difficult and takes a lot of time. Disclosure of Invention Technical Problem

[11] Accordingly, it is an aspect of the present invention to provide a pipe coupling device which couples pipes by a simple manipulation without deforming the pipes.

[12] Also, it is another aspect of the present invention to provide a pipe coupling device which connects pipes more firmly by fixing external and internal circumferences of connecting pipes at the same time. Technical Solution

[13] Additional aspects and advantages of the general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept.

[14] An aspect of the present invention can be achieved by providing a pipe coupling device which couples and fixes end parts of connecting pipes, the device comprising front and rear external coupling members which are shaped like a cylinder to insert end parts of the pipes thereinto and have manipulation holes drilled in an external circumference facing each other; an internal coupling member which has a flow hole formed in an internal part of a round bar-shaped body inserted into an internal part of the front and rear external coupling members in forward and backward directions to communicate with an internal hole of the pipes, and has gear installing grooves formed corresponding to the manipulation holes, respectively; a pair of fixing gear units which have an input gear installed in the gear installing grooves of the internal coupling member and an output gear rotatably installed in the internal coupling member to be engaged with the input gear; front and rear external fixing means which are formed in opposite sides of the internal coupling member to press and fix an external circumference of the pipes by moving outwardly when the fixing gear units rotate; front and rear internal fixing means which are formed in opposite sides of the internal coupling member to press and is tightly connected to the internal circumference of the pipes by moving outwardly when the fixing gear units rotate.

[15] The front and rear external fixing means comprise an external pressure member which is coupled with the output gear to move together with the output gear, and has a screw part formed in an external circumference and coupled to the internal circumference of the front and rear external coupling members to move forward and backward; and a pressure ring which is provided in an external part of the internal coupling member to press and fix the external circumference of the pipes by contracting by a pressure applied when the external pressure member moves forward, and to be separated from the external circumference of the pipes by extending when the external pressure member moves backward and the pressure is released.

[16] The pressure ring comprises a plurality of pressure projections which protrudes at predetermined internals from the internal circumference of a round body having a cutting part to tightly contact the external circumference of the pipes.

[17] The tight member comprises a plurality of washers which is inserted into the external circumference of the internal coupling member at predetermined intervals; and a plurality of O-rings which is inserted between the washers.

[18] The fixing gear units comprise a bevel gear unit in which a plurality of input gears is engaged with a single output gear, the input gear comprises a supporting projection protruding from an upper surface of a conical gear body and a manipulative tool coupler formed in a lower surface of the gear body toward the manipulation hole, and the output gear comprises a plurality of internal projections which protrudes at predetermined angles so that the internal fixing means contact and are fixed to an internal circumference of a central hole, and a plurality of external projections which protrudes at predetermined angles to contact and be fixed by the external fixing means.

[19] The manipulative tool coupler comprises a tool coupling member whose first end is inserted into a fitting groove formed in a lower surface of the gear body and second end protruding to the outside through the manipulation hole of the front and rear external coupling members has a tool insertion groove, or a tool coupling member which is formed in the lower surface of the gear body and has a tool insertion groove.

[20] The front and rear external coupling members comprise an interference preventing groove which is formed in a predetermined width in an internal circumference around the manipulation groove not to create an interference when the input gear provided therein rotates; and a jaw which is formed in an insertion part of the pipes corresponding to a second side of the interference preventing groove and has a reduced internal diameter to prevent the front and rear external fixing means from being separated.

Advantageous Effects

[21] As described above, the present invention provides a pipe coupling device which couples pipes without deforming the pipes since screw threads are not formed or a welding is not performed, and connects pipes simply and efficiently with a gear type operation mechanism.

[22] Also, the present invention provides a pipe coupling device which connects pipes more firmly by fixing external and internal circumferences of connecting pipes at the same time.

Brief Description of the Drawings

[23] These and other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompany drawings of which: [24] FIG. 1 is a cut perspective view of a pipe coupling device according to an exemplary embodiment of the present invention; [25] FIG. 2 is a perspective view of a separated first side of the pipe coupling device according to the exemplary embodiment of the present invention; [26] FIG. 3 is a cut perspective view of front and rear external coupling members of the pipe coupling device according to the exemplary embodiment of the present invention; [27] FIG. 4 is a cut perspective view of an internal coupling member of the pipe coupling device according to the exemplary embodiment of the present invention; [28] FIG. 5 is a cut perspective view of a fixing gear unit of the pipe coupling device according to the exemplary embodiment of the present invention; [29] FIG. 6 is a perspective view of a pressure ring of front and rear external fixing means employed in the pipe coupling device according to the exemplary embodiment of the present invention; [30] FIG. 7 is a perspective view of an internal pressure member of front and rear internal fixing means employed in the pipe coupling device according to the exemplary embodiment of the present invention; and [31] FIG. 8 is a sectional view of illustrating an operation of the pipe coupling device according to the exemplary embodiment of the present invention.

Best Mode for Carrying Out the Invention [32] Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures. [33] FIG. 1 is a cut perspective view of a pipe coupling device according to an exemplary embodiment of the present invention. FIG. 2 is a perspective view of a separated first side of the pipe coupling device according to the exemplary embodiment of the present invention. [34] Referring to FIGS. 1 and 2, the pipe coupling device according to the exemplary embodiment of the present invention includes front and rear external coupling members 10 and 10' into which end parts of connecting pipes a and b are inserted, an internal coupling member 20 to be inserted into the front and rear external coupling members 10 and 10' a pair of fixing gear units 30 and 30' to be installed in the internal coupling member 20, front and rear external fixing means 40 and 40' to be provided in opposite sides of the internal coupling member 20 and front and rear internal fixing means 50 and 50'.

[35] FIG. 3 is a cut perspective view of the front and rear external coupling members 10 and 10' of the pipe coupling device according to the exemplary embodiment of the present invention.

[36] As shown in FIG. 2 and 3, the front and rear external coupling members 10 and 10' are inserted into the end parts of the pipes a and b connected to a first side of a body 11 substantially shaped like a cylinder, wherein a manipulation hole 12 is drilled on an external circumference of a second side of the cylindrical body 11. The front and rear external coupling members 10 and 10' are aligned in a straight line so that the manipulation holes 12 face each other.

[37] An interference preventing groove 14 is formed in an internal circumference corresponding to an area of the manipulation hole 12 of the cylindrical body 11 in a predetermined width not to create an interference when an input gear 31 (to be described later) rotates.

[38] A jaw 16 which has a reduced internal diameter is formed in the second side of the cylindrical body 11 not to separate the front and rear external fixing means 40 and 40' installed therein while a connector 15 is formed in the internal circumference contacting the jaw 16 in predetermined length.

[39] FIG. 4 is a cut perspective view of the internal coupling member 20 of the pipe coupling device according to the exemplary embodiment of the present invention.

[40] As shown in FIGS. 2 and 4, the internal coupling member 20 includes a body 21 shaped like a round bar having a large diameter part 21a formed in a center thereof and a small diameter part 21b formed in opposite sides of the large diameter part 21a. A flow hole 22 is formed in forward and back directions to communicate with an internal hole of the pipes 10 and 10' connected to the body 21.

[41] A connector 23 is formed in the small diameter part 21b contacting the large diameter part 21a to be connected with an internal pressure member 52 (to be described later) while a connector 25 is formed in an end part of the small diameter part 21b to be connected with a fixing nut 56 (to be described later). Gear installing grooves 24 are formed in opposite sides of the large diameter part 21a corresponding to the manipulation hole 12 of the external coupling members 10 and 10'.

[42] The gear installing grooves 24 are shaped like a cone which has a small lower part and a large upper part so that the input gear 31 including a bevel gear is easily accommodated to rotate, and include an opening part to expose the input gear 31 therethrough and allow an output gear 32 to be engaged with saw teeth.

[43] A supporting groove 24a is formed in a lower surface of the gear installing grooves

24 to insert a supporting projection 3 Ie protruding from the end part of the input gear 31 thereinto and to be rotatably supported.

[44] FIG. 5 is a cut perspective view of the fixing gear units 30 and 30' of the pipe coupling device according to the exemplary embodiment of the present invention.

[45] As shown in FIGS. 1 and 5, the fixing gear units 30 and 30' are provided in a pair to fix and release the connected pipes. The fixing gear units 30 and 30' include the input gear 31 to be installed in the gear installing grooves 24 of the internal coupling member 20; and the output gear 32 to be rotatably installed in the internal coupling member 20 to thereby be engaged with the input gear 31.

[46] Preferably, the fixing gear units 30 and 30' include a bevel gear unit which has a single output gear 32 and a plurality of input gears 31.

[47] The supporting projection 3 Ie protrudes from an upper surface of the conical gear body 31a of the input gear 31 to be rotatably inserted into the gear installing grooves 24 of the internal coupling member 20 while a manipulative tool coupler 31b is provided in a lower surface of the gear body 31a to be in the same line as the manipulation hole 12.

[48] A first end of the manipulative tool coupler 3 Ib is inserted into a fitting groove 31c formed in the lower surface of the gear body 31a while a second end thereof protruding to the outside through the manipulation groove 12 of the front and rear external coupling members 10 and 10' is coupled with a tool coupling member 3 Id having a tool insertion groove therein, but not limited thereto. Alternatively, the tool coupling member 3 Id having the tool insertion groove protrudes from the lower end of the gear body 31a to be exposed to the outside through the manipulation hole 12.

[49] In the present embodiment, the tool coupling member 3 Id includes a hexagonal bar having the tool insertion groove to insert a hexagonal wrench thereinto while the fitting groove 31c is shaped like a hexagonal groove to insert the tool coupling member 3 Id thereinto, but not limited thereto. Alternatively, the tool coupling member 3 Id and fitting groove 31c may vary to have rectangular and hemispheric sections.

[50] The output gear 32 includes a plurality of internal projections 32b formed at predetermined angles to connect and fix the front and rear internal fixing means 50 and 50' and a plurality of external projections 32c formed at predetermined angles to connect and fix the front and rear external fixing means 40 and 40'. The internal projections 32b are formed in an internal circumference of a central hole of the output gear 32 while the external projections 32c are formed on an external circumference of a boss protruding to the outside of the output gear 32.

[51] FIG. 6 is a perspective view of the pressure ring 44 of the front and rear external fixing means 40 and 40' employed in the pipe coupling device according to the exemplary embodiment of the present invention.

[52] As shown in FIGS. 1 and 2, the front and rear external fixing means 40 and 40' are provided in opposite sides of the internal coupling member 20 to press and fix or release the external circumference of the pipes a and b by outwardly moving when the fixing gear unit 30 rotates.

[53] The external pressure member 42 includes a screw part 42a which is connected with the connector 15 of the front and rear external coupling members 10 and 10' in the external circumference of the body coupled with the output gear 32 to move together with the output gear 32 and having a ring shape, and is coupled and decoupled by a rotational direction of the output gear 32; and a plurality of connection grooves 42b which is formed at predetermined angles in the internal circumference of the ring- shaped body and fitted between the external projections 32c of the output gear 32.

[54] As shown in FIG. 6, the pressure ring 44 is provided in an external part of the internal coupling member 20 corresponding to an internal part of the front and rear external coupling members 10 and 10' to contract inwardly to thereby press and fix the external circumference of the pipes a and b by a pressure generated by a forward movement of the external pressure member 42. If the pressure is released by a backward movement of the external pressure member 42, the pressure ring 44 extends and returns to be separated from the external circumference of the pipes a and b.

[55] Preferably, the pressure ring 44 includes a plurality of pressure projections 44a which protrudes at predetermined intervals from an internal circumference of a circular body having a cutting part and is tightly pressed to the external circumference of the pipes a and b to provide fixing force.

[56] FIG. 7 is a perspective view of the internal pressure member 52 of the front and rear internal fixing means 50 and 50' employed in the pipe coupling device according to the exemplary embodiment of the present invention.

[57] As shown in FIGS. 1 and 2, the front and rear internal fixing means 50 and 50' are provided in opposite sides of the internal coupling member 20 to move outwardly and be tightly pressed to the internal circumference of the pipes a and b or to be separated if the fixing gear units 30 and 30' rotate by an applied manipulative force. The front and rear internal fixing means 50 and 50' include the internal pressure member 52, a tight member 54 and a fixing nut 56.

[58] As shown in FIG. 7, the internal pressure member 52 includes a screw part 52a which is connected with a central connector 23 (left and right sides contacting the large diameter part of the internal coupling member) of the internal coupling member 20 in the internal circumference of the cylindrical body coupled with the output gear 32 and moving forward and backward; and a plurality of connection grooves 42b which is formed at predetermined angles in the external circumference of the body and fitted between the internal projections 32b of the output gear 32.

[59] The tight member 54 is formed in the external part of the internal coupling member

20 to thereby extend and fix to the internal circumference of the pipes a and b by a pressure generated when the internal pressure member 52 moves outwardly.

[60] The tight member 54 includes a plurality of washers 54a which is inserted into the external circumference (external part of the small diameter part) of the internal coupling member 20 at predetermined intervals; and a plurality of O-rings 54 which includes a flexible material such as rubber and inserted between the washers 54a.

[61] The fixing nut 56 includes a ring-shaped nut which is connected with the connector

25 of the internal coupling member 20 to support the tight member 54 and prevent the tight member 54 from being separated from the internal coupling member 20.

[62] A pitch of a screw thread of the connector 15 formed in the internal circumference of the front and rear external coupling members 10 and 10' is larger than that of the central connector 23 of the internal coupling member 20 so that the external pressure member 42 and the internal pressure member 52 have different moving distances for a single rotation of the output gear 32 as the external pressure member 42 connected to the connector of the external coupling member requires a larger movement to press the external circumference of the pressure ring 44 and the internal pressure member 52 pressing the tight member 54 requires a relatively smaller movement.

[63] The connector 15 of the front and rear external coupling members 10 and 10 is coupled with the screw part 42a of the external pressure member 42, and the connector 23 of the internal coupling member 20 is coupled with the screw part 52a. Thus, the screw threads are formed to have the same pitch. The pitches of the screw threads may vary depending on a width of the pressure ring 44 and extension and contraction of the tight member 54.

[64] Hereinafter, an operation of the pipe coupling device according to the exemplary embodiment of the present invention will be described.

[65] FIG. 8 is a sectional view of illustrating the operation of the pipe coupling device according to the exemplary embodiment of the present invention.

[66] Referring to FIGS. 1, 2 and 8, the pipe coupling device according to the exemplary embodiment of the present invention includes the internal pressure member 52 to couple the screw part 52a and the central connector 23 of the internal coupling member 20; and the output gear 32 to fit and couple the projections 32b to the connection grooves 52b formed in the external circumference of the internal pressure member 52.

[67] The washers 54a and O-rings 54b are sequentially inserted into the opposite sides of the internal coupling member 20, and the fixing nut 56 is fixed to the end part of the internal coupling member 20 to prevent the washers 54a and O-rings 54b from being separated therefrom.

[68] The external pressure member 42 is inserted to fit and couple the connection grooves 42b to the external projections 32 of the output gear 32 while the pressure ring 44 is inserted into the external pressure member 42 corresponding to a vicinity of the washers 54a and O-rings 54b.

[69] Then, the input gear 31 is inserted into the gear installing grooves 24 of the internal coupling member 20 and then the front and rear external coupling members 10 and 10' are inserted into the opposite sides of the internal coupling member 20 to complete the assembly process. Here, the input gear 31 is positioned in the internal inference preventing groove 14 of the front and rear external coupling members 10 and 10' and the tool coupling member 3 Id is inserted into the fitting groove 31c of the input gear 31 through the manipulation hole 12.

[70] Hereinafter, a process of coupling the pipes a and b with the assembled pipe coupling device will be described. First, if the end parts of the pipes a and b are slid between the front and rear external coupling members 10 and 10 , and the internal coupling member 20, the external circumference of the pipes a and b is positioned in the internal part of the pressure ring 44 and the internal circumference of the pipes a and b is positioned in the installing part of the washers 54a and O-rings 54b.

[71] If a tool such as the hexagonal wrench is inserted into the tool insertion groove of the tool coupling member 3 Id and the manipulation force is applied thereto, the input gear 31 rotates in a preset direction (e.g., clockwise) and the engaged output gear 32 also rotates.

[72] If the output gear 32 rotates, the internal pressure member 52 connected to the internal projection 32b and the external pressure member 42 connected to the external projections 32c move together with the rotation.

[73] Then, the internal pressure member 52 connected to the central connector 23 of the internal coupling member 20 is disconnected therefrom and moves outwardly. Thus, the external end part of the internal pressure member 52 applies a pressure to the washers 54a and O-rings 54b and enables the O-rings 54 having the flexible material to extend to the internal circumference of the pipes a and b and to press and fix the internal circumference thereof.

[74] The external pressure member 42 rotates clockwise and is connected to the connector 15 of the external coupling members 10 and 10' to move outwardly. Then, the internal circumference of the external pressure member 42 is fitted to the external circumference of the pressure ring 44 to apply a pressure to an axial center of the internal coupling member 20.

[75] Then, the pressure ring 44 contracts to the external circumference of the pipes a and b, and the plurality of pressure projections 44a formed in the internal circumference thereof presses and fixes the external circumference of the pipes a and b.

[76] The pipe coupling device according to the present invention may maintain the fixing status more firmly by fixing the external circumference of the connecting pipes with the front and rear external fixing means 40 and 40 including the external pressure member 42 and the pressure ring 44, and by fixing the internal circumference of the connecting pipes with the front and rear internal fixing means 50 and 50' including the washers 54a, the O-rings 54b and the fixing nut 56.

[77] As the external and internal fixing means 40 and 50 operate by a mechanism of the bevel gear, the pipes may be connected with each other by a simple manual tool without additional coupling equipment.

[78] Although a few exemplary embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

[1] A pipe coupling device which couples and fixes end parts of connecting pipes, the device comprising: front and rear external coupling members which are shaped like a cylinder to insert end parts of the pipes thereinto and have manipulation holes drilled in an external circumference to face each other; an internal coupling member which has a flow hole formed in an internal part of a round bar-shaped body inserted into an internal part of the front and rear external coupling members in forward and backward directions to communicate with an internal hole of the pipes, and has gear installing grooves formed corresponding to the manipulation holes, respectively; a pair of fixing gear units which have an input gear installed in the gear installing grooves of the internal coupling member, and an output gear rotatably installed in the internal coupling member to be engaged with the input gear; front and rear external fixing means which are formed in opposite sides of the internal coupling member to press and fix an external circumference of the pipes by moving outwardly when the fixing gear units rotate; front and rear internal fixing means which are formed in opposite sides of the internal coupling member to press and tightly contact the internal circumference of the pipes by moving outwardly when the fixing gear units rotate, wherein the front and rear internal fixing means comprise an internal pressure member which is coupled with the output gear to move together with the output gear, and moves forward and backward by coupling and decoupling a screw part formed in an internal circumference of a cylindrical body, to the internal coupling member; a tight member which is provided in an external part of the internal coupling member to extend and tightly contact the internal circumference of the pipes by a pressure applied when the internal pressure member moves forward; and a fixing nut which is connected to opposite connectors of the internal coupling member to support the tight member and to prevent the tight member from being separated from the internal coupling member.

[2] The device according to claim 1, wherein the front and rear external fixing means comprise an external pressure member which is coupled with the output gear to move together with the output gear, and has a screw part formed in an external circumference and coupled to the internal circumference of the front and rear external coupling members to move forward and backward; and a pressure ring which is provided in an external part of the internal coupling member to press and fix the external circumference of the pipes by contracting by a pressure applied when the external pressure member moves forward, and to be separated from the external circumference of the pipes by extending when the external pressure member moves backward and the pressure is released.

[3] The device according to claim 2, wherein the pressure ring comprises a plurality of pressure projections which protrudes at predetermined internals from the internal circumference of a round body having a cutting part to tightly contact the external circumference of the pipes.

[4] The device according to claim 1, wherein the tight member comprises a plurality of washers which is inserted into the external circumference of the internal coupling member at predetermined intervals; and a plurality of O-rings which is inserted between the washers.

[5] The device according to one of claims 1 to 4, wherein the fixing gear units comprise a bevel gear unit in which a plurality of input gears is engaged with a single output gear, the input gear comprises a supporting projection protruding from an upper surface of a conical gear body and a manipulative tool coupler formed in a lower surface of the gear body toward the manipulation hole, and the output gear comprises a plurality of internal projections which protrudes at predetermined angles so that the internal fixing means contact and are fixed to an internal circumference of a central hole, and a plurality of external projections which protrudes at predetermined angles to contact and be fixed by the external fixing means.

[6] The device according to claim 5, wherein the manipulative tool coupler comprises a tool coupling member whose first end is inserted into a fitting groove formed in a lower surface of the gear body and second end protruding to the outside through the manipulation hole of the front and rear external coupling members has a tool insertion groove, or a tool coupling member which is formed in the lower surface of the gear body and has a tool insertion groove.

[7] The device according to claim 5, wherein the front and rear external coupling members comprise an interference preventing groove which is formed in a predetermined width in an internal circumference around the manipulation groove not to create an interference when the input gear provided therein rotates; and a jaw which is formed in an insertion part of the pipes corresponding to a second side of the interference preventing groove and has a reduced internal diameter to prevent the front and rear external fixing means from being separated.