Abstract:
An endoscope device includes an insertion portion cover as an insertion portion main body insertable into an examinee&#39;s body and having flexibility, and a helical shaped portion as a propulsion force generating portion which is rotatably placed around an outer circumference of the insertion portion cover, centered around the axis thereof, and formed in a clockwise winding toward a distal end side of the insertion portion cover. The endoscope device can thus achieve good operationality of the insertion portion, low cost, and improved insertability into a deep part in a body cavity without inflicting a pain on a patient.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of Japanese Application No. 2006-6796 filed on Jan. 13, 2006, the contents of which are incorporated by this reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an endoscope device including an insertion portion main body having flexibility which is insertable into an examinee&#39;s body, an endoscope system, and a method for inserting the endoscope device into a body cavity. 
         [0004]    2. Description of the Related Art 
         [0005]    Conventionally, medical endoscope devices have been widely used. With the medical endoscope device, an elongate insertion portion is inserted into a body cavity to observe a diseased part or the like in the body cavity, and a treatment tool is inserted through a forceps channel as required to allow a curing treatment to be performed. The endoscope device has a bendable bending portion at a distal end side of the insertion portion. In the endoscope device, the bendable bending portion is bent and operated in up/down or left/right directions by operating a bending operation knob. 
         [0006]    When the endoscope device is inserted into a convoluted intracavital canal, e.g., a lumen forming a loop of 360 degrees such as the large intestine, the bending operation knob is operated to bend and operate the bending portion, while the insertion portion is twisted and operated to be inserted toward an observation target position. However, the operation of the endoscope requires mastery to be able to insert the insertion portion smoothly in a short period of time into a deep part in the convoluted large intestine. It was concerned that an inexperienced surgeon, lost in the insertion direction, has trouble in inserting the insertion portion into the deep part in the large intestine, or greatly change the way the intestine runs. 
         [0007]    For this reason, various proposals have conventionally been made for improving the insertability of the insertion portion. For example, Japanese unexamined patent publication No. 10-113396 discloses a propulsion device for medical apparatus capable of easily and low-invasively guiding a medical apparatus into a deep part of an intracavital canal. The propulsion device has a rotation member provided in the axial direction thereof with a diagonal rib serving as a propulsion force generating portion. Thus, in the propulsion device described in the publication, with rotational motion of the rotation member, rotational force of the rotation member is converted to a propulsion force by the rib, and the medical apparatus connected to the propulsion device is moved toward the deep part of the intracavital canal by the propulsion force. In this manner, the propulsion device described in Japanese unexamined patent publication No. 10-113396 can insert a medical apparatus into a body cavity low-invasively without inflicting a patient with a physical burden. 
       SUMMARY OF THE INVENTION 
       [0008]    An endoscope device according to one aspect of the present invention includes: an insertion portion main body having flexibility which is insertable into an examinee&#39;s body; a rotation propulsion portion rotatably placed around an outer circumference near a distal end of the insertion portion main body and centered around an axis of the insertion portion main body, the rotation propulsion portion having on an outer circumference thereof a helical shaped portion serving as a propulsion force generating portion; and a rotation transmission shaft having flexibility for transmitting rotation force to the rotation propulsion portion from a proximal end side of the insertion portion main body, wherein the helical shaped portion has a helix formed in a direction to exhibit a propulsion force to the direction of the distal end of the insertion portion when the rotation transmission shaft is rotated clockwise toward the distal end of the insertion portion main body. 
         [0009]    An endoscope system according to another aspect of the present invention includes: an endoscope device including: an insertion portion main body having flexibility which is insertable into an examinee&#39;s body; a rotation propulsion portion rotatably placed around an outer circumference near a distal end of the insertion portion main body and centered around an axis of the insertion portion main body, the rotation propulsion portion having on an outer circumference thereof a helical shaped portion serving as a propulsion force generating portion; and a rotation transmission shaft having flexibility for transmitting rotation force to the rotation propulsion portion from a proximal end side of the insertion portion main body, the helical shaped portion being helically formed in a direction to exhibit propulsion force toward the distal end of the insertion portion when the rotation transmission shaft is rotated clockwise toward the distal end of the insertion portion main body; and a rotation device for rotating the helical shaped portion of the endoscope device about a longitudinal axis of the helical shaped portion. 
         [0010]    A method for inserting an endoscope device into a body cavity according to yet another aspect of the present invention includes: inserting an endoscope device into an opening of an intracavital canal, the endoscope device including: an insertion portion main body having flexibility which is insertable into an examinee&#39;s body; a rotation propulsion portion placed around an outer circumference near a distal end of the insertion portion main body and centered around an axis of the insertion portion main body, the rotation propulsion portion having on an outer circumference thereof a helical shaped portion serving as a propulsion force generating portion; and a rotation transmission shaft having flexibility for transmitting rotation force to the rotation propulsion portion from a proximal end side of the insertion portion main body, the helical shaped portion having a helix formed in a direction to exhibit a propulsion force to the direction of the distal end of the insertion portion when the rotation transmission shaft is rotated clockwise toward the distal end of the insertion portion main body; rotating the helical shaped portion of the endoscope device inserted into the opening of the intracavital canal, clockwise about a longitudinal axis of the insertion portion main body; propelling the insertion portion main body toward a deep part of the intracavital canal, by obtaining a propulsion force between the helical shaped portion and an inner wall of the intracavital canal by the helical shaped portion which is rotating clockwise about the longitudinal axis of the insertion portion main body; and generally linearizing the body cavity, by propelling the endoscope device toward the deep part of the intracavital canal while drawing the body cavity to right side of the examinee&#39;s body by means of friction action of the helical shaped portion rotating clockwise about the longitudinal direction of the insertion portion main body so as to shorten the body cavity. 
         [0011]    The endoscope device and the endoscope system according to these inventions have good operationality of the insertion portion, are low-cost, and have an effect of being capable of improving the insertability to the deep part of the intracavital canal without inflicting a patient with pain. 
         [0012]    The above and other objects, features, and advantages of the inventions will become more clearly understood from the following description referring to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a general configuration view showing an endoscope system of one embodiment of the present invention. 
           [0014]      FIG. 2  is an external view showing a vicinity of a distal end portion of an introduction tube of  FIG. 1 . 
           [0015]      FIG. 3  is an illustrative view showing the introduction tube and an endoscope of  FIG. 1 . 
           [0016]      FIG. 4  is a cross-sectional view taken along the line IV-IV of  FIG. 3 . 
           [0017]      FIG. 5  is an illustrative view showing a configuration of a rotation mechanism portion. 
           [0018]      FIG. 6  is an illustrative view of a main portion showing a vicinity of the distal end portion of the introduction tube of  FIG. 2 . 
           [0019]      FIG. 7  is an illustrative view showing a state where an introduction tube in which an insertion portion is introduced and placed is introduced from the anus. 
           [0020]      FIG. 8  is an illustrative view showing a state where the distal end portion of the introduction tube contacts the Sigmoid colon portion from the state shown in  FIG. 7 , thereby interrupting the rotation of a helical tube. 
           [0021]      FIG. 9  is an illustrative view showing a situation where the Sigmoid colon portion is applied with a rotation force from the helical tube in the state shown in  FIG. 8 . 
           [0022]      FIG. 10  is an illustrative view showing a situation where the distal end portion of the introduction tube is moving forward in the Sigmoid colon portion from the state shown in  FIG. 9 . 
           [0023]      FIG. 11  is an illustrative view showing a situation where the distal end portion of the introduction tube is moving forward via the Sigmoid colon portion from the state shown in  FIG. 10 . 
           [0024]      FIG. 12  is an illustrative view showing a situation where the distal end portion of the introduction tube is moving forward to the descending colon portion from the state shown in  FIG. 11 . 
           [0025]      FIG. 13  is an illustrative view showing a situation where the distal end portion of the introduction tube has reached the hepatic flexure from the state shown in  FIG. 12 , and the transverse colon portion, the splenic flexure, and the hepatic flexure are generally applied with rotation force from the helical tube. 
           [0026]      FIG. 14  is an illustrative view of a situation where the transverse colon portion, the splenic flexure, and the hepatic flexure are generally linearized from the state shown in  FIG. 13 . 
           [0027]      FIG. 15  is an illustrative view showing a modified example of the introduction tube. 
           [0028]      FIG. 16  is a cross-sectional view taken along the line XVI-XVI of  FIG. 15 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0029]    An embodiment of the present invention will be described below with reference to the drawings. 
         [0030]      FIGS. 1 to 16  relate to the embodiment of the present invention, wherein: FIG.  1  is a general configuration view showing an endoscope system;  FIG. 2  is an external view showing a vicinity of a distal end portion of an introduction tube of  FIG. 1 ;  FIG. 3  is an illustrative view showing the introduction tube and an endoscope of  FIG. 1 ;  FIG. 4  is a cross-sectional view taken along the line IV-IV of  FIG. 3 ;  FIG. 5  is an illustrative view showing a configuration of a rotation mechanism portion;  FIG. 6  is an illustrative view of a main portion showing a vicinity of the distal end portion of the introduction tube of  FIG. 2 ;  FIG. 7  is an illustrative view showing a state where an introduction tube in which an insertion portion is introduced and placed is introduced from the anus;  FIG. 8  is an illustrative view showing a state where the distal end portion of the introduction tube contacts the Sigmoid colon portion from the state shown in  FIG. 7 , thereby interrupting the rotation of a helical tube;  FIG. 9  is an illustrative view showing a situation where the Sigmoid colon portion is applied with a rotation force from the helical tube in the state shown in  FIG. 8 ;  FIG. 10  is an illustrative view showing a situation where the distal end portion of the introduction tube is moving forward in the Sigmoid colon portion from the state shown in  FIG. 9 ;  FIG. 11  is an illustrative view showing a situation where the distal end portion of the introduction tube is moving forward via the Sigmoid colon portion from the state shown in  FIG. 10 ;  FIG. 12  is an illustrative view showing a situation where the distal end portion of the introduction tube is moving forward to the descending colon portion from the state shown in  FIG. 11 ;  FIG. 13  is an illustrative view showing a situation where the distal end portion of the introduction tube has reached hepatic flexure from the state shown in  FIG. 12 , and the transverse colon portion, the splenic flexure, and the hepatic flexure are generally applied with rotation force from the helical tube;  FIG. 14  is an illustrative view of a situation where the transverse colon portion, the splenic flexure, and the hepatic flexure are generally linearized from the state shown in  FIG. 13 ;  FIG. 15  is an illustrative view showing a modified example of the introduction tube; and  FIG. 16  is a cross-sectional view taken along the line XVI-XVI of  FIG. 15 . 
         [0031]    As shown in  FIGS. 1 to 4 , an endoscope system  1  includes an endoscope  2  and an endoscope insertion-assisting apparatus  3 . The endoscope  2  is connected to a light source device  4  for supplying illumination light, a video processor  5 , a monitor  6 , and the like, which are external devices. The endoscope  2  is supplied with illumination light from the light source device  4 , and illuminates a subject with the illumination light. The endoscope  2  captures an image of the illuminated subject from an object optical system not shown, and then outputs an image-capturing signal obtained by photoelectrically converting the captured image with an image-capturing element, to the video processor  5 . The video processor  5  signal-processes the image-capturing signal from the image-capturing element to generate a video signal, and outputs and displays the signal to the monitor  6 . Note that the endoscope  2  may not be provided with the light source device  4 , and instead a distal end portion  15  may be provided with an illumination portion such as LEDs. 
         [0032]    The endoscope  2  includes an endoscope insertion portion  11  which is elongate and has flexibility, an operation portion  12  provided on a proximal end side of the endoscope insertion portion  11 , and a universal code  13  extending from a side portion of the operation portion  12 . The endoscope insertion portion  11  is constructed by connecting in series the rigid distal end portion  15 , a bendable bending portion  16 , and a flexible tube portion  17  which is long and has flexibility, in this order from the distal end side. 
         [0033]    In the operation portion  12  is provided a bending operation knob not shown for bending and operating the bending portion  16 . In the endoscope  2 , the bending portion  16  is bent and operated in a freely bendable manner by operating the bending operation knob. Note that an introduction tube  20  to be described later in which the endoscope  2  is to be inserted and placed is constructed to bend following the bending motion of the bending portion  16  of the endoscope  2 . 
         [0034]    The endoscope insertion-assisting apparatus  3  includes the introduction tube  20  in which the endoscope insertion portion  11  is inserted and placed so as to guide the endoscope insertion portion  11  toward a deep part in the body cavity, and a rotation device  40  for rotating a helical tube  23  to be described later of the introduction tube  20 . 
         [0035]    The rotation device  40  includes, e.g., an arm portion  41  having one end portion attached to, e.g., the ceiling of an inspection room, and a rotation mechanism portion  42  attached to the other end portion of the arm portion  41 . The arm portion  41  includes a plurality of arm members  41   a  differing, e.g., in length, and joint portions  41   b  for rotatably connecting the adjacent arm members  41   a . This permits the rotation device  40  to move the position of the rotation mechanism portion  42  to any position with a small amount of force. Detailed configuration of the rotation mechanism portion  42  will be described later. 
         [0036]    As shown in  FIGS. 2 to 4 , the introduction tube  20  includes: an insertion portion cover  10  serving as an insertion portion main body which is formed from an observation window member  24  and an elastic cover tube  21 ; a proximal-side component member  22  provided continuously to the insertion portion cover  10 ; and a helical tube  23  which is placed around an outer circumferential side of the insertion portion cover  10  and forms a helical shaped portion  23   b  serving as a propulsion force generating portion for generating a propulsion force. 
         [0037]    That is, the insertion portion cover  10  serving as the insertion portion main body is equipped with the helical tube  23  which is placed around the outer circumferential surface side and forms the helical shaped portion  23   b  serving as the propulsion force generating portion that rotates about the longitudinal axis thereof. The helical tube  23  constructs a rotation propulsion portion and a rotation transmission shaft. 
         [0038]    The elastic cover tube  21  is formed in an elongate tubular shape by a member having a small frictional resistance, e.g., fluorocarbon resin such as PTFE (polytetrafluoroethylene resin) and the like. The elastic cover tube  21  is formed with a through-hole  21  a penetrating therethrough in the axial direction in which the endoscope insertion portion  11  is to be inserted and placed. 
         [0039]    Also, in the elastic cover tube  21 , a channel  21   b  serving as an air and water supplying duct is formed in the axial direction. Further, in the elastic cover tube  21 , a channel  21   c  serving as a treatment tool insertion duct or a suction duct is formed in the axial direction, as shown in  FIG. 4 . 
         [0040]    At a front surface on the distal end side of the elastic cover tube  21 , the observation window member  24  is placed to an opening on a distal end side of the through-hole  21   a , integrally with the elastic cover tube  21  by adhesion or the like. A proximal end side of the through-hole  21   a  communicates with a penetration hole  22   a  to be described later which is formed in the proximal-side component member  22 . 
         [0041]    The observation window member  24  is formed by a transparent resin member, e.g., polycarbonate and the like, having an optical characteristic. The observation window member  24  has an inner surface to be contacted with a front surface of the distal end portion  15  constructing a part of the endoscope insertion portion  11  when the endoscope insertion portion  11  is inserted and placed in the through-hole  21   a . The observation window member  24  serves to water-tightly seal the front opening of the elastic cover tube  21 , and as an observation window of the endoscope  2 . 
         [0042]    The channel  21   b  has one end side communicating with an air and water supplying nozzle  25  placed near the distal end portion of the elastic cover tube  21 . The air and water supplying nozzle  25  has an opening which is opposed to the observation window member  24 . On the other end side of the channel  21   b  is provided a clasp portion  26  projecting from an outer circumference of the proximal-side component member  22 . 
         [0043]    To the clasp portion  26 , one end of an air and water supplying tube  27   a  is connected. The other end of the air and water supplying tube  27   a  is connected with an air and water supplying device  27 . The air and water supplying device  27  can be driven and controlled through press-operating an air and water supplying pressing button-switch  28 . 
         [0044]    The air and water supplying device  27  can be driven by press-operating the air and water supplying pressing button-switch  28 , to supply a fluid such as air and liquid to the channel  21   b  to spout out the fluid from the opening of the air and water supplying nozzle  25  to the surface of the observation window member  24 , as shown with an arrow. 
         [0045]    With this, when the surface of the observation window member  24  is adhered with, e.g., a filth and the like, the introduction tube  20  can wash away the adhering filth by spouting out water from the opening of the air and water supplying nozzle  25 . Moreover, the introduction tube  20  can remove beads of moisture adhering on the surface of the observation window member  24  by supplying air from the opening of the air and water supplying nozzle  25 . 
         [0046]    The channel  21   c  communicates with a channel opening portion formed at a predetermined position of the proximal-side component member  22 . When the channel  21   c  is used as a treatment tool insertion channel, a treatment tool, e.g., a biopsy needle, biopsy forceps, and so on, is inserted to the channel opening portion. 
         [0047]    The treatment tool is inserted through the channel  21   c  and projects from a distal end opening of the elastic cover tube  21 , thus allowing a prescribed treatment to be performed. When the channel  21   c  is used as a suction channel, one end of a channel connection member is provided and placed to the channel opening portion, and the other end of the channel connection member is connected to a suction duct (not shown) extended from, e.g., a suction device (not shown). 
         [0048]    The suction device can be driven and controlled by press-operating a suction pressing button-switch  29 . With this, the introduction tube  20  can suck body fluid and the like in the body cavity from the distal end opening of the elastic cover tube  21  by the sucking operation of the suction device. 
         [0049]    Accordingly, in the endoscope  2 , a distal end surface of the endoscope insertion portion  11  is only provided with an observation window  18  constructing an observation optical system and an illumination window  19  constructing an illumination optical system, in order to reduce the diameter of the endoscope insertion portion  11 . 
         [0050]    The helical tube  23  is formed by winding a metal wire with a predetermined diameter dimension in a helical shape to have a predetermined flexibility. The metal wire is made of, e.g., stainless. Thus, on the outer surface of the helical tube  23 , the helical shaped portion  23   b  is formed by the surface of the metal wire. The helical tube  23  covers the circumferential surface of the elastic cover tube  21  with a gap  23   c  formed between an inner circumferential surface of the helical shaped portion  23   b  and the outer circumferential surface of the elastic cover tube  21 , and is placed rotatably in a circumferential direction (about the axis) with respect to the outer circumferential surface of the elastic cover tube  21 . Note that the helical tube  23  rotates in the circumferential direction (about the axis) by the rotation mechanism portion  42  of the rotation device  40 , as will be described later. 
         [0051]    The helical tube  23  is not limited to one-stria construction, but may be formed by a winding in multiple striae, e.g., two or four striae, and the like. Also, the helical tube  23  can be adjusted in propulsion force, progression speed, and so forth, by varying the density of the metal wire and making various helical angle settings when helically winding the metal wire. 
         [0052]    On a distal end portion of the outer circumferential surface of the elastic cover tube  21 , a convex portion  21  d is provided for preventing the helical tube  23  from dropping off. The helical tube  23  is restricted in its forward movement in that a front end portion  23   da  contacts and is stopped by a rear surface portion  21   dd  of the convex portion  21   d.    
         [0053]    The helical tube  23  is also restricted in its backward movement in that a rear end portion  23   db  contacts and is stopped by a front surface portion  22   e  of the proximal-side component member  22 . Accordingly, the helical tube  23  always maintain the state of covering the outer circumferential side of the elastic cover tube  21 , in that the front end portion  23   da  is stopped by the rear surface portion  21   dd  of the convex portion  21   d  on the front end side, and the rear end portion  23   db  by the front surface portion  21   e  of the proximal-side component member  22  on the rear end side. 
         [0054]    On the other hand, the proximal-side component member  22  is a tubular member larger in diameter than the elastic cover tube  21 , and is formed by a resin member with a good slidability, e.g., Polyacetal and the like. Inside the proximal-side component member  22 , the penetration hole  22   a  is bored and provided in which a part of the distal end side of the operation portion  12  of the endoscope  2  (part of a breaking prevention portion  12   a ) is to be inserted and placed. 
         [0055]    On an inner circumferential surface on a rear end side of the penetration hole  22   a , a plurality of inwardly projecting stopping convex portions  22   b  are projectingly provided. The plurality of stopping convex portions  22   b  are configured to fit in a circumferential groove  12   b  formed to the breaking prevention portion  12   a  of the operation portion  12  of the endoscope  2 . 
         [0056]    With this, the introduction tube  20  fixes and holds the endoscope  2  in that the plurality of stopping convex portions  22   b  fits in the circumferential groove  12   b  when the endoscope insertion portion  11  is inserted inside the elastic cover tube  21  and a part of the distal end side of the operation portion  12  is placed inside the proximal-side component member  22 . 
         [0057]    In addition, in the front surface portion  22   e  of the proximal-side component member  22 , a part of a proximal end portion  21   e  of the elastic cover tube  21  fits. Thus, the elastic cover tube  21  is formed to integrate with the proximal-side component member  22 . 
         [0058]    As shown in  FIG. 5 , the rotation mechanism portion  42  has a rotation portion main body  43  which is a housing, a motor  44 , a rotation force transmission member  45 , and a guiding tube holding portion  46 . 
         [0059]    The motor  44  generates driving force for rotating the helical tube  23  about the longitudinal axis thereof. The motor  44  is fixedly provided on, e.g., a side wall of the rotation portion main body  43 . The motor  44  has a motor shaft  44   a  to which the rotation force transmission member  45  is integrally fixed. 
         [0060]    The rotation force transmission member  45  is formed of an elastic resin member. The guiding tube holding portion  46  is placed opposed to the rotation force transmission member  45  fixed to the motor shaft  44   a.    
         [0061]    The guiding tube holding portion  46  is fixedly provided on, e.g., a bottom portion of the rotation portion main body  43 . On a flat surface of the guiding tube holding portion  46  opposing to the rotation force transmission member  45  is formed a semicircular concave portion (not shown) that approximately agrees with the external shape of the helical tube  23  or the proximal-side component member  22 . 
         [0062]    The rotation mechanism portion  42  is configured such that the helical tube  23  constructing the introduction tube  20  is placed and held sandwiched between the rotation force transmission member  45  and the concave portion of the guiding tube holding portion  46 . 
         [0063]    Therefore, with the introduction tube  20 , when the motor  44  is driven with the helical tube  23  placed between the rotation force transmission member  45  and the guiding tube holding portion  46 , the rotation force transmission member  45  fixed to the motor shaft  44   a  is rotated, and the rotation driving force is transmitted to the helical tube  23  via the rotation force transmission member  45 . The helical tube  23  thus transmitted with the rotation force rotates about the axis, with respect to the elastic cover tube  21  in the gap  23   c  formed between the inner circumferential surface of the helical shaped portion  23   b  and the elastic cover tube  21 . 
         [0064]    When the introduction tube  20  is inserted into a body cavity, the rotation of the helical tube  23  generates a propulsion force as that of a male screw moving with respect to a female screw, at a contacting portion between the helical shaped portion  23   b  and the intestine wall. This propulsion force causes the helical tube  23  to move toward the axial direction of the introduction tube  20  while rotating. 
         [0065]    At this time, one end (the front end portion  23   da ) of the helical tube  23  is positionally restricted at a position to contact the convex portion  21   d  of the elastic cover tube  21 , and the other end (the rear end portion  23   db ) at a position to contact the front surface portion  22   e  of the proximal-side component member  22 . This results in the integration of the helical tube  23  and the elastic cover tube  21 . Therefore, as the helical tube  23  moves, the elastic cover tube  21  moves in the same moving direction as that of the helical tube  23 . 
         [0066]    Also, at this time, in the introduction tube  20 , the elastic cover tube  21  and the endoscope  2  are integrated by the fitting between the stopping convex portions  22   b  and the circumferential groove  12   b , in a state shown in  FIG. 3 , that is, a state where the endoscope insertion portion  11  is inserted into the elastic cover tube  21  and the stopping convex portions  22   b  is fitted in the circumferential groove  12   b.    
         [0067]    Accordingly, the endoscope  2  moves in the same moving direction as that of the introduction tube  20  constructed by the helical tube  23  and the elastic cover tube  21 , thereby moving toward the deep part of the intracavital canal. 
         [0068]    As shown in  FIG. 6 , the introduction tube  20  has, around the outer circumferential surface of the insertion portion cover  10 , the helical tube  23  having the helical shaped portion  23   b  formed in a clockwise winding toward the distal end side. The helical tube  23  forms the helical shaped portion  23   b  by winding the metal wire in a clockwise helical shape toward the distal end side. In other words, the helical tube  23  forms the helical shaped portion  23   b  by winding the metal wire in a helical shape in the same direction as that of a thread of a clockwise screw. 
         [0069]    This results in that, in the introduction tube  20 , the helical tube  23  is rotated clockwise about the longitudinal axis toward the insertion direction by the rotation device  40  to obtain propulsion force between the helical shaped portion  23   b  and the inner wall of the intracavital canal. Further, the helical tube  23  rotating clockwise about the longitudinal axis toward the insertion direction causes the Sigmoid colon portion to be drawn clockwise viewed from the front of the body and thus shortened, and the transverse colon upward in the canal and thus shortened, thereby generally linearizing the intestinal canal, which permits the introduction tube  20  to move forward to the deep part of the intracavital canal, as will be described later. 
         [0070]    Now, operations of the endoscope system  1  constructed as described above will be described. 
         [0071]    First, a medical staff (abbreviated as “staff”) prepares the endoscope  2  and the introduction tube  20  constructing the endoscope insertion-assisting apparatus  3 . The staff moves the arm portion  41  of the rotation device  40  constructing the endoscope insertion-assisting apparatus  3  to place the rotation mechanism portion  42  at a desired position. 
         [0072]    Next, the staff places a desired position of the helical tube  23  constructing the introduction tube  20  between the guiding tube holding portion  46  constructing the rotation mechanism portion  42  and the rotation force transmission member  45 . This placement results in a state where the proximal end portion side of the introduction tube  20  is held by the rotation mechanism portion  42 . At this time, the distal end portion side of the introduction tube  20  is placed, e.g., above a bed  7 . 
         [0073]    Then, the staff inserts and places the endoscope insertion portion  11  into the introduction tube  20  from the opening of the proximal-side component member  22  constructing the introduction tube  20 . This results in a state where the endoscope  2  has the endoscope insertion portion  11  covered by the introduction tube  20 , therewith completing the preparation for inserting the endoscope  2  into, e.g., the large intestine. 
         [0074]    The staff also prepares the light source device  4 , the video processor  5 , and the monitor  6 , which are peripheral devices, along with the preparation for the endoscope  2 , the introduction tube  20 , and the rotation device  40 . 
         [0075]    Next, steps for inserting the endoscope  2  covered by the introduction tube  20  into the large intestine will be described. First, as an insertion step, a surgeon (not shown) holds the distal end side of the introduction tube  20 , and then inserts the distal end side of the introduction tube  20  into the large intestine from the anus of a patient  8  lying on the bed  7 . 
         [0076]    The introduction tube  20  with the distal end portion now inserted into the anus of the patient  8 , has the helical shaped portion  23   b  formed on the external surface of the helical tube  23  in contact with the intestine wall. At this time, the relation between the helical shaped portion  23   b  and the intestine wall in contact to each other is that between male and female screws. Also, an endoscope image captured by the image-capturing element of the endoscope  2  is displayed on a screen of the monitor  6 . 
         [0077]    In the state where the helical shaped portion  23   b  is in contact with the intestine wall, the surgeon drives to rotate the motor  44  of the rotation mechanism portion  42  by a predetermined operation, as a rotation step. At this time, the surgeon operates to rotate and drive the motor  44  of the rotation mechanism portion  42  in a clockwise direction about the longitudinal axis in the insertion direction of the introduction tube  20 . 
         [0078]    In the rotation mechanism portion  42 , driving the motor  44  to rotate clockwise causes the rotation force transmission member  45  to rotate clockwise via the motor shaft  44   a . The rotation driving force of the rotation force transmission member  45  is transmitted to the helical tube  23  placed between the rotation force transmission member  45  and the guiding tube holding portion  46 . 
         [0079]    Thus, the helical tube  23  starts rotating clockwise about the longitudinal axis as shown in an arrow R in  FIG. 7 . At this time, at a contacting portion between the helical shaped portion  23   b  of the helical tube  23  which is rotating clockwise about the longitudinal axis and the intestine wall, there is a relation such as that of a clockwise screw moving with respect to a female screw, i.e., propulsion force for moving forward the helical tube  23  is generated. 
         [0080]    As described above, the helical tube  23  has one end (the front end portion  23   da ) positionally restricted at a position to contact the convex portion  21   d  of the elastic cover tube  21 , and the other end (the rear end portion  23   db ) at a position to contact the front surface portion  22   e  of the proximal-side component member  22 , leading to integration between the helical tube  23  and the elastic cover tube  21 . With this integration, the helical tube  23  is prevented from dropping off from the elastic cover tube  21 , while contacting and pushing the rear surface portion  21   dd  of the convex portion  21   d  of the elastic cover tube  21  to move forward. 
         [0081]    In this manner, the introduction tube  20  constructed by the helical tube  23  and the elastic cover tube  21  moves forward to the deep part in the large intestine by the propulsion force generated as a propulsion step. 
         [0082]    At this time, the introduction tube  20  is integrated with the endoscope  2 , because the proximal-side component member  22  of the introduction tube  20  has the stopping convex portions  22   b  fitted with the circumferential groove  12   b . Therefore, as the introduction tube  20  moves, the endoscope  2  moves in the same direction thus being inserted into the deep part in the body cavity of the examinee. 
         [0083]    In this state, when the surgeon makes an operation at hand such as to push forward the introduction tube  20 , the introduction tube  20  with the endoscope insertion portion  11  inserted therein is introduced toward the intracavital deep part with a small amount of force. That is, the introduction tube  20  inserted from the anus  71  is moved from the rectum  72  toward the Sigmoid colon portion  73  by the propulsion force, at-hand operation and bending operation by the surgeon, or the like, with the endoscope insertion portion  11  being inserted in the introduction tube  20 . 
         [0084]    As shown in  FIG. 8 , when reaching the Sigmoid colon portion  73 , the distal end of the introduction tube  20  contacts a bending portion by a scope, thus preventing the helical tube  23  from rotating. 
         [0085]    As described above, the introduction tube  20  includes the helical tube  23  having the helical shaped portion  23   b  formed in a clockwise winding toward the distal end side, the helical tube  23  being provided around the outer circumference of the insertion portion cover  10 . 
         [0086]    For this reason, the rotated helical tube  23  is applied with a force as shown in an arrow shown in  FIG. 9 , thus twisting the introduction tube  20  in a clockwise direction as viewed from the front of the body. 
         [0087]    As a result, as the linearization step, the introduction tube  20  draws the Sigmoid colon portion clockwise viewed from the front of the body to thereby shorten and generally linearize the same, while moving forward to the deep part of the intracavital canal, as shown in  FIG. 10 . 
         [0088]    That is, in the present embodiment, an intracavital insertion method (large intestine insertion method) of the endoscope device includes the insertion step, the rotation step, the propulsion step, and the linearization step. This allows the introduction tube  20  to exhibit a sufficient propulsion function when being inserted into the large intestine, permitting for easy insertion of the endoscope insertion portion  11  into the deep part in the large intestine. 
         [0089]    In some cases, the observation window member  24  of the introduction tube  20  is adhered with, e.g., a filth and the like. In this case, the surgeon press-operates the air and water supplying pressing button-switch  28  twice. 
         [0090]    With the introduction tube  20 , the air and water supplying device  27  is activated to supply water through the channel  21   b  to spout out, e.g., water from the opening of the air and water supplying nozzle  25  as indicated with the arrow shown in  FIG. 3 . In this manner, the introduction tube  20  can wash away the filth of the like adhering to the observation window member  24 . 
         [0091]    Also, the surgeon press-operates the air and water supplying pressing button-switch  28  once. In the introduction tube  20 , the air and water supplying device  27  is activated to supply air through the channel  21   b  to spout out, e.g., air from the opening of the air and water supplying nozzle  25  as indicated with the arrow shown in  FIG. 3 . Thus, the introduction tube  20  can remove beads of moisture adhering on the surface of the observation window member  24 . The surgeon also press-operates the suction pressing button-switch  29 . The suction device is activated to suck body liquid and the like from the opening of the channel  21   c , in the introduction tube  20 . 
         [0092]    Thereafter, the rotating introduction tube  20  passes through the Sigmoid colon portion  73  which is generally linearized as shown in  FIG. 11 , to further move forward to the descending colon portion  74  having low movability as shown in  FIG. 12 . The introduction tube  20  passes through the splenic flexure  76 , which is an interface between the descending colon portion  74  and the transverse colon portion  75  having high movability, to smoothly move forward along the wall of the hepatic flexure  77  which is an interface between the transverse colon  75  and the ascending colon  78 . 
         [0093]    As shown in  FIG. 13 , when reaching the hepatic flexure  77 , the distal end of the introduction tube  20  contacts a middle bending portion of the transverse colon, thus interrupting the rotation of the helical tube  23 . At this time, the helical tube  23  being rotated is applied with forces shown in arrows so as to upwardly twist the introduction tube  20 , as described referring to  FIG. 9 , 
         [0094]    As a result, the introduction tube  20  generally draws upward as viewed from the front of the body and thus shortens the transverse colon  75 , the splenic flexure  76 , and the hepatic flexure  77 , as shown in  FIG. 14 , as the linearization step. 
         [0095]    After this step, though not shown, the introduction tube  20  moves forward, so that the distal end portion reaches, e.g., near the cecum portion  79  which is the destination position. The surgeon, on determining that the distal end portion of the introduction tube  20  has reached near the cecum portion  79  from an endoscope imaged displayed on the screen of the monitor  6 , directs, e.g., a staff to stop the driving of the motor  44 . The surgeon steps forward to pulling back the endoscope insertion portion  11  to perform large intestine endoscopy. 
         [0096]    After the endoscopy is complete, the surgeon draws the endoscope insertion portion  11  out from the introduction tube  20  and discards the introduction tube  20 . While at the same time, the surgeon inserts and places the endoscope insertion portion  11  into an unused new introduction tube  20 . This permits the surgeon to perform the next inspection with the endoscope system  1  without cleaning and sterilizing the endoscope  2 . 
         [0097]    As described above, the introduction tube  20 , which has around the outer circumference of the insertion portion cover  10  the helical tube  23  including the helical shaped portion  23   b  formed in a clockwise winding toward the distal end side, can move forward to the deep part in the body cavity, in that rotating the helical tube  23  clockwise about the longitudinal axis allows obtaining a propulsion force between the helical shaped portion  23   b  and the inner wall of the intracavital canal, while drawing the Sigmoid colon portion clockwise viewed from the front of the body to shorten the same, and drawing the transverse colon  75  upward the canal to shorten the same, thus generally linearizing the gut. 
         [0098]    This makes it possible to insert the introduction tube  20  into the deep part in the large intestine along with the endoscope insertion portion  11 , even if the introduction tube  20  does not have a very large total length, whereby providing a good operationality and reducing the production cost. 
         [0099]    Also, the introduction tube  20  can surely prevent the endoscope insertion portion  11  from directly contacting the wall of the body cavity during inspection by inserting and placing the endoscope insertion portion  11  in the introduction tube  20 . Accordingly, the staff is released from the trouble of cleaning and sterilizing the endoscope  2  and the introduction tube  20  every time an inspection is complete, by combining the endoscope  2  drawn out from the introduction tube  20  with a new introduction tube  20  for reuse after the inspection, instead of cleaning and sterilizing the endoscope  2 . 
         [0100]    Note that, although in the present embodiment, the rotation driving force of the motor  44  is transmitted to the proximal end side of the helical tube  23  which is a rotating cylindrical body in order to rotate the entire helical tube  23 , the present invention is not limited thereto, but the rotation driving force of the motor  44  may be transmitted to, e.g., a middle portion or a distal end portion of the helical tube  23  to rotate the entire helical tube  23 . 
         [0101]    Further, although in the present embodiment, the insertion portion cover  10  that covers the endoscope insertion portion  11  is constructed as the insertion portion main body around which outer circumference being provided with the helical shaped portion  23   b  serving as the propulsion force generating portion, the present invention is not limited thereto, but the endoscope insertion portion may be the insertion portion main body, and a helical shaped portion be provided around the outer circumference of the endoscope insertion portion. 
         [0102]    Furthermore, although in the present embodiment, the introduction tube is provided in the whole length with a helical tube that is wound clockwise, and the helical tube is rotated clockwise to perform both propulsion and linearization, the introduction tube may be constructed as shown in, e.g.,  FIGS. 15 and 16 . 
         [0103]    As shown in  FIGS. 15 and 16 , an introduction tube  20 B, which is a modified example of the above-described embodiment, has a cylindrical helical portion  81  provided on a distal end of the elastic cover tube  21 . The cylindrical helical portion  81  has an outer circumferential surface formed with a counterclockwise-wound helical shaped portion. The cylindrical helical portion  81  is rotatably constructed, connected to a rotation shaft (e.g., flexible shaft)  82  inserted into an insertion hole  83  of the elastic cover tube  21 . The rotation shaft  82  is formed of multi-layers of metal wires knitted in a cylindrical mesh shape. The rotation shaft  82  has flexibility as well as rotation followability. 
         [0104]    To a distal end portion  84  of the rotation shaft  82  is provided with a transmission gear  84   a  which engages with a transmission gear  81   a  formed on an inner circumferential surface of the cylindrical helical portion  81 . A proximal end side of the rotation shaft  82  is rotatably constructed, connected to a rotation device not shown. Other constructions are almost the same as in the above-described embodiment. 
         [0105]    The introduction tube  20 B is constructed such that clockwise rotation of the rotation shaft  82  causes the cylindrical helical portion  81  having the counterclockwise-wound helical shaped portion to rotate clockwise. 
         [0106]    With this construction, the introduction tube  20 B can move forward to the deep part in the body cavity, in that rotating the helical tube  23  clockwise about the longitudinal axis allows obtaining a propulsion force between the helical shaped portion  23   b  and the inner wall of the intracavital canal, while drawing the Sigmoid colon portion clockwise viewed from the front of the body to shorten the same, and drawing the transverse colon upward the canal to shorten the same, thus generally linearizing the gut. 
         [0107]    Note that, although in the modification example above, the cylindrical helical portion  81  and the rotation shaft  82  are constructed to rotate via a gear, the shaft and the propulsion portion may be integrated without the intermediary of the gear so that the rotation directions agree to each other. 
         [0108]    The inventions described in the above embodiment are not limited to the embodiment and modification thereof, but can be embodied in other various modifications without departing from the spirit at the stage of practice. Further, the above-described embodiment includes various stages of inventions, and various inventions can be extracted from appropriate combinations of a plurality of disclosed components. 
         [0109]    For example, if the problems mentioned in description of related art can be solved and the effects of the present invention recited in detailed description of preferred embodiments can be obtained even if a several components are deleted from all the components shown in the above-described embodiment, the construction deleted of the components can be extracted as an invention. 
         [0110]    Having described the preferred embodiments of the invention referring to the accompanying drawings, it should be understood that the present invention is not limited to those precise embodiments and various changes and modifications thereof could be made by one skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims.