Abstract:
The present invention provides a balloon unit for an endoscope apparatus comprising: a balloon for an endoscope apparatus having an opening formed in a cylindrical shape in which an insert part of an endoscope or an insert supporter having the insert part inserted therein is inserted and fixed; and a cylinder body having an inner diameter larger than an outer diameter of the insert part or the insert supporter; wherein the opening of the balloon is fitted over and fixed to the cylinder body to form a unit and the unit is attached to the insert part or the insert supporter or detached from the insert part or the insert supporter.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a balloon unit for an endoscope apparatus, and particularly relates to a balloon unit for an endoscope apparatus which is attached to an endoscope for observing small bowel and large bowel. 
     2. Description of the Related Art 
     In endoscope apparatuses, balloons which can expand and contract are used for various purposes. For example, in an endoscope apparatus for observing deep alimentary canals such as small bowel and large bowel, an expandable balloon is attached to an endoscope insert part or an endoscope insert supporter (such as a sliding tube or an over tube), so that the endoscope insert part or the insert supporter can be fixed to a viscera by expanding the balloon. In an ultrasonic diagnosis apparatus, an expandable balloon is used to surround an ultrasonic scan part at a tip of an ultrasonic probe and fill an ultrasonic transmitting medium. In an ultrasonic endoscope, an expandable balloon is used to surround an ultrasonic transducer at a tip of an insert part and fill an ultrasonic transmitting medium. 
     Such a balloon for endoscope is made of an elastic body such as rubber and an end of the balloon is formed in a cylindrical shape having a diameter smaller than an outer diameter of an object to be attached (the endoscope insert part or the insert supporter, for example). When the balloon is attached, the object to be attached is covered with the end of the balloon while enlarging the diameter of the end. Thereafter, thread is wound or a rubber band is fitted over the end of the balloon so as to fix the end of the balloon to the object to be attached. 
     However, there is a problem that the task of covering the object to be attached with the end of the balloon while enlarging the diameter of the end of the balloon is very onerous and the attachment task is troublesome. 
     Thus, in Japanese Patent Application Laid-Open No. 5-15487, a method is described in which a balloon is adsorbed and attached on an inner circumferential surface of a cylinder body. According to this method, an inner diameter of the balloon can be enlarged by adsorbing the balloon on the inner circumferential surface of the cylinder body, so that the insert part or the insert supporter can be easily inserted therethrough. 
     However, the attachment method in Japanese Patent Application Laid-Open No. 5-15487 has problems that a special attachment jig is required and a task of attaching the special attachment jig to the balloon is troublesome and thus the balloon can not be quickly attached. 
     In addition, the method in Japanese Patent Application Laid-Open No. 5-15487 is adapted to attach a balloon to an endoscope having a fluid supplying and sucking port in an outer circumferential surface of an insert part. If there is no fluid supplying and sucking port in the insert part, it is necessary to insert a tip of a tube deeply into the balloon. Therefore, there are problems that the task of attaching the balloon is troublesome and air-tightness between the balloon and the insert part after attachment is low. 
     The present invention is provided in view of the above problems and it is an object of the present invention to provide a balloon unit for an endoscope apparatus which can be quickly and easily attached to an object to be attached such as an endoscope insert part or an insert supporter. 
     SUMMARY OF THE INVENTION 
     To accomplish the above object, a first aspect of the present invention provides a balloon unit for an endoscope apparatus comprising: a balloon for an endoscope apparatus having an opening formed in a cylindrical shape in which an insert part of an endoscope or an insert supporter having the insert part inserted therein is inserted and fixed, and a cylinder body having an inner diameter larger than an outer diameter of the insert part or the insert supporter, wherein the opening of the balloon is fitted over and fixed to the cylinder body to form a unit and the unit is attached to the insert part or the insert supporter or detached from the insert part or the insert supporter. 
     According to the first aspect, because the opening (the end) of the balloon is fitted over the cylinder body to form a unit, the insert part or the insert supporter can be easily covered with the end of the balloon by inserting the insert part or the insert supporter through the cylinder body. 
     A second aspect of the present invention is that, in the first aspect, a tube for supplying and sucking fluid into/from the balloon for an endoscope apparatus is connected to the cylinder body. 
     According to the second aspect of the invention, because the tube for supplying and sucking fluid is connected to the cylinder body, the balloon can be also attached to an endoscope even having no duct for supplying and sucking fluid in its insert part, so as to provide a balloon(-equipped) endoscope. That is, according to the second aspect, even if an endoscope is not a special endoscope having a duct for supplying and sucking fluid in its insert part, the balloon unit can be afterwards attached to the endoscope to provide a balloon endoscope. 
     A third aspect of the present invention is that, in the second aspect, a flow passage for supplying and sucking fluid into/from the balloon for an endoscope apparatus is formed in the cylinder body and the tube is connected to an end of the flow passage. 
     According to the third aspect of the invention, because the flow passage is formed in the cylinder body and the tube is connected to the flow passage, it is not necessary to insert the tube deeply into the balloon. Therefore, the task of attaching the balloon can be easily performed and air-tightness in the fixing part (the opening) of the balloon can be sufficiently ensured. 
     A fourth aspect of the present invention is that, in the third aspect, in the end of the flow passage of the cylinder body, a connector is provided to which the tube is detachably connected. 
     According to the fourth aspect of the invention, because the connector is provided in the end of the flow passage of the cylinder body, the tube can be detachably connected. Therefore, the tube can be connected to the connector after inserting the insert part or the insert supporter through the cylinder body and thus the task of inserting the insert part or the insert supporter through the cylinder body can be easily performed. 
     A fifth aspect of the present invention is that, in any one of the first to fourth aspects, a doughnut-shaped balloon for attachment, through which the insert part or the insert supporter is inserted, is provided on an inner side of the cylinder body, and the cylinder body is fixed to the insert part or the insert supporter by expanding the balloon for attachment so that the balloon for attachment presses an outer circumferential surface of the insert part or the insert supporter. 
     According to the fifth aspect of the invention, because the cylinder body is fixed to the insert part or the insert supporter by expanding the balloon for attachment, the cylinder body can be reliably fixed regardless of diameter of the insert part or the insert supporter. 
     In addition, in the fifth aspect of the invention, the feature of expanding and fixing the balloon for attachment allows large clearance between the inner circumferential surface of the cylinder body and the outer circumferential surface of the insert part or the insert supporter, so that the insert part or the insert supporter can be easily inserted through the cylinder body. 
     Further, according to the fifth aspect of the invention, a gap between the outer circumferential surface of the insert part or the insert supporter and the inner circumferential surface of the cylinder body can be reliably sealed by the balloon for attachment. 
     In the fifth aspect, it is preferable to provide a device which controls supply pressure of fluid supplied to the balloon for attachment, depending on the outer diameter dimension of the insert part or the insert supporter. 
     A sixth aspect of the present invention is, in the first aspect, a flow passage for supplying and sucking fluid into/from the balloon for an endoscope apparatus is formed in the cylinder body; a doughnut-shaped balloon for attachment, through which the insert part or the insert supporter is inserted, is provided on an inner side of the cylinder body, and the cylinder body is fixed to the insert part or the insert supporter by expanding the balloon for attachment so that the balloon for attachment presses an outer circumferential surface of the insert part or the insert supporter; and further the flow passage of the cylinder body is branched to communicate with the balloon for attachment; and a branch passage of the flow passage is provided with a check valve. 
     According to the sixth aspect of the invention, because the flow passage of the cylinder body is branched to communicate with the balloon for attachment, the balloon for attachment can be expanded by the fluid which is used to expand the balloon. In addition, according to the sixth aspect of the invention, because the branch part of the flow passage is provided with a check valve, fluid does not flow out from the balloon for attachment when air is sucked from the balloon to contract the balloon. Thus, contraction of the balloon for attachment can be prevented. 
     According to the present invention, because the opening (the end) of the balloon is fitted over the cylinder body to form a unit, the insert part or the insert supporter can be easily covered with the end of the balloon by inserting the insert part or the insert supporter through the cylinder body. Therefore, the task of attaching the balloon can be easily performed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a system configuration view of an endoscope apparatus to which a balloon unit for an endoscope apparatus according to the present invention is applied; 
         FIG. 2  is a perspective view showing the balloon unit; 
         FIG. 3  is a cross sectional view of the balloon unit in  FIG. 2 ; 
         FIG. 4  is a cross sectional view showing a cylinder body; 
         FIG. 5  is a cross sectional view showing the cylinder body through which an insert part is inserted; 
         FIG. 6  is a cross sectional view showing the cylinder body fixed to the insert part; 
         FIG. 7  is a cross sectional view showing the balloon unit through which the insert part is inserted; 
         FIG. 8  is a cross sectional view showing a balloon unit in which cylinder bodies are covered with both ends for fixing; 
         FIG. 9  is a cross sectional view showing a balloon unit in another embodiment; and 
         FIG. 10  is a cross sectional view showing an attachment condition of the balloon unit in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Now, preferred embodiments of a balloon unit for an endoscope apparatus according to the present invention will be described in detail with reference to the accompanied drawings. 
       FIG. 1  is a system configuration view showing an example of an endoscope apparatus to which the balloon unit for an endoscope apparatus according to the present invention is applied. As shown in  FIG. 1 , the endoscope apparatus mainly includes an endoscope  10 , a balloon for an endoscope apparatus (referred to as a balloon, hereinafter)  60 , and a balloon controlling apparatus  100 . 
     The endoscope  10  includes a hand operating part  14  and an insert part  12  which is connected to the hand operating part  14  and is to be inserted into a body cavity. A universal cable  16  is connected to the hand operating part  14  and a LG connector  18  is provided at a tip of the universal cable  16 . The LG connector  18  is detachably coupled to a light source apparatus  20  so that illumination light is transmitted to an illumination optics (not shown) provided at a tip of the insert part  12 . In addition, an electrical connector  24  is connected to the LG connector  18  via a cable  22  and the electrical connector  24  is detachably coupled to a processor  26 . 
     In the hand operating part  14 , an air/water supply button  28 , a suck button  30 , a shutter button  32 , and a function switch button  34  are provided side by side and a pair of angle knobs  36 ,  36  is provided. 
     The insert part  12  is composed of a soft part  40 , a bend part  42 , and a tip part  44  in this order from the side of the hand operating part  14 . The soft part  40  is made by covering an outer circumference of a metal plate, which is wound in a spiral shape, with a net and further covering the outer circumference with a coating, so that the soft part  40  has sufficient flexibility. The soft part  40  is connected to a base end of the bend part  42 . 
     The bend part  42  is configured to be remotely bent by turning the angle knobs  36 ,  36  of the hand operating part  14 . For example, in the bend part  42 , a plurality of cylindrical sections are rotatably coupled by pins and a plurality of operating wires are inserted into the sections through and guided by the pins so that the operating wires are moved forward and backward. Thereby, the sections rotate with respect to each other to bend the bend part  42 . By bending the bend part  42 , the tip part  44  can be oriented in a desired direction. 
     Although not shown, the tip part  44  is provided with an observation optics, an illumination optics, an air/water supply nozzle, and a forceps port on its tip surface, for example. A CCD is disposed behind the observation optics and a signal cable is connected to a substrate which supports the CCD. The signal cable is inserted through the insert part  12 , the hand operating part  14 , the universal cable  16  and the like and extended to the electrical connector  24  so that the cable is connected to the processor  26 . Therefore, an observed image captured by the observation optics is focused on a light receiving surface of the CCD and converted into an electrical signal. Then, the electrical signal is output to the processor  26  through the signal cable and converted into an image signal. As a result, the observed image is displayed on a monitor  50  which is connected to the processor  26 . 
     An output end of a light guide is positioned behind the illumination optics, and the light guide is inserted through the insert part  12 , the hand operating part  14 , and the universal cable  16  so that an input end of the light guide is positioned in the LG connector  18 . Therefore, by coupling the LG connector  18  to the light source apparatus  20 , illumination light radiated from the light source apparatus  20  is transmitted through the light guide to the illumination optics and radiated forward from the illumination optics. 
     The air/water supply nozzle is linked to a valve which is operated with the air/water supply button  28  and the valve is linked to an air/water supply connector  48  which is provided in the LG connector  18 . An air/water supplying device (not shown) is connected to the air/water supply connector  48  to supply air and water. Therefore, by operating the air/water supply button  28 , air or water can be sprayed from the air/water supply nozzle toward the observation optics. 
     The forceps port is communicated with a forceps insert part  46 . Therefore, by inserting an operative instrument such as a forceps from the forceps insert part  46 , the operative instrument can be guided out through the forceps port. In addition, the forceps port is linked to a valve which is operated with the suck button  30  and the valve is connected to a suck connector  49  of the LG connector  18 . Therefore, by connecting a sucking device (not shown) to the suck connector  49  and actuating the valve with the suck button  30 , lesions and the like can be sucked from the forceps port. 
     As shown in  FIGS. 2 and 3 , the balloon  60  is formed in a generally cylindrical shape with narrow both ends and the balloon  60  is composed of ends  60 A,  60 B having a small diameter and a center swelled part  60 C. The balloon  60  is made of an elastic material such as natural rubber, silicone rubber or the like and is positioned and fixed in a predetermined position (the soft part  40 , for example) of the insert part  12 , by inserting the insert part  12  through the balloon  60 . 
     The end  60 B of the balloon  60  has an inner diameter D 1  (see  FIG. 3 ) formed somewhat smaller than an outer diameter D 2  of the insert part  12 . By inserting the insert part  12  through while elastically deforming the end  60 B to enlarge its diameter, the end  60 B tightly contacts the whole outer circumferential surface of the insert part  12  after attachment. Thus, there is no gap between the end  60 B and the insert part  12  so that high air-tightness can be obtained. 
     The end  60 A of the balloon  60  is fitted over and fixed to a hard cylinder body  62  so that a balloon unit is configured by the cylinder body  62  and the balloon  60 . The end  60 A of the balloon  60  has an inner diameter formed somewhat smaller than the outer diameter of the cylinder body  62  and is fitted over the cylinder body  62  while elastically deforming the end  60 A to enlarge its diameter. As a result, the end  60 A is fixed in such a manner that it tightly contacts the whole outer circumferential surface of the cylinder body  62 . The end  60 A of the balloon  60  and the cylinder body  62  are fixed, for example, by winding thread on the outer side of the end  60 A or by applying and solidifying adhesive, although not particularly limited to these. 
     The cylinder body  62  is formed in a cylindrical shape with a material which can keep its shape such as metal or resin. The cylinder body  62  may be made of one material or may be made of two or more materials by applying and solidifying melt resin on the outer circumference of a metal ring, for example. 
     As shown in  FIG. 4 , the flow passage (hole)  63  is provided in the cylinder body  62 . The flow passage  63  is formed in an axial direction of the cylinder body  62  and opened in both end surfaces. In other words, the flow passage  63  has an opening  63 A in an inner end surface (the right end surface in  FIG. 4 )  62 A of the balloon  60  and an opening  63 B in an outer end surface (the left end surface in  FIG. 4 ) of the balloon  62 B. In addition, the flow passage  63  is branched halfway and a tip of a branch passage  63 C is opened in the inner circumferential surface of the cylinder body  62  and an inner side of the balloon for attachment  66 . 
     The balloon for attachment  66  is formed in a cylindrical shape with an elastic body such as rubber and fixed on the inner circumferential surface of the cylinder body  62 . In both ends of the balloon for attachment  66 , its whole outer circumferential surface is stuck on the inner circumferential surface of the cylinder body  62 , so that the balloon for attachment  66  is expanded in a doughnut shape as shown in  FIG. 6  by supplying fluid from the branch passage  63 C to the balloon for attachment  66 . 
     The balloon for attachment  66  has an inner diameter D 3  (see  FIG. 3 ) formed somewhat larger than the outer diameter D 2  of the insert part  12  when it is contracted as shown in  FIG. 5 , so that the insert part  12  can be inserted through the inner cylinder  62 . When the balloon for attachment  66  is expanded as shown in  FIG. 6 , the inner diameter of a swelled part (which is a part having the smallest inner diameter) of the balloon for attachment  66  is smaller than the outer diameter D 2  of the insert part  12 , so that the balloon for attachment  66  presses the whole outer circumferential surface of the insert part  12 . In this way, the cylinder body  62  can be fixed to the insert part  12  and a ring-shaped gap between the inner circumferential surface of the cylinder body  62  and the outer circumferential surface of the insert part  12  can be sealed by the balloon for attachment  66 . 
     It is preferable that the balloon for attachment  66  is easier to expand than the balloon  60 . For example, thickness of the balloon for attachment  66  may be formed thinner than thickness of the balloon  60  or elongation percentage of the balloon for attachment  66  may be set larger than elongation percentage of the balloon  60 . 
     The branch passage  63 C is provided with an elastic piece  68  as a check valve. The elastic piece  68  is provided so that its one end is fixed to the cylinder body  62  and shuts the branch passage  63 C, as shown in  FIGS. 4 and 5 . When fluid is supplied through the branch passage  63 C to the balloon for attachment  66 , the elastic piece  68  is elastically deformed to allow fluid to flow through, as shown in  FIG. 6 . When pressure of fluid in the branch passage  68 C decreases, the elastic piece  68  returns to its original shape and shuts the branch passage  68 C to prevent backflow of fluid. Therefore, contraction of the expanded balloon for attachment  66  can be prevented. The configuration for the check valve is not limited to the above described configuration and any configuration may be employed which allows fluid supply to the balloon for attachment  66  and prevents fluid discharge from the balloon for attachment  66 . 
     As shown in  FIG. 5 , a connector is formed in the end  63 B of the flow passage  63  and an end  64 B of a tube  64  is detachably coupled to the connector. A lure-lock mechanism is used for the connector, for example. Thus, the end  63 B and the end  64 B can be coupled while maintaining air-tightness between the tube  64  and the flow passage  63 . 
     As shown in  FIG. 1 , a connector is provided at an end  64 A on a base end side of the tube  64  and a tube  110  of the balloon controlling apparatus  100  is detachably coupled to the connector. Therefore, air can be supplied and sucked through the tubes  110 ,  64  to/from the flow passage  63  of the cylinder body  62  by supplying and sucking fluid (air, for example) from/to the balloon controlling apparatus  100 . Thereby, the balloon for attachment  66  can be expanded to fix the cylinder body  62  to the insert part  12  so that the balloon  60  is fixed to the insert part  12 , and air can be supplied to/sucked from the balloon  60 . The balloon  60  expands in a generally spherical shape by supplying air and sticks on the outer surface of the insert part  12  by sucking air. The method of expanding the balloon for attachment  66  in order to fix the balloon  60  to the insert part  12  will be described later. 
     After the balloon  60  is fixed to the insert part  12 , the tube  64  may be placed along the insert part  12  and fixed to the insert part  12  with a tape and the like. Further, the end  64 A on the base end side of the tube  64  may be engaged to an engaging part which may be provided in the hand operating part  14 . 
     The balloon controlling apparatus  100  is an apparatus for supplying and sucking fluid such as air to/from the balloon  60 . The balloon controlling apparatus  100  mainly includes an apparatus body  102  and a hand switch  104  for remote control. 
     On a front side of the apparatus body  102 , a power switch SW 1 , a stop switch SW 2 , and a pressure displaying part  106  are provided. The pressure displaying part  106  is a panel on which pressure value of the balloon  60  is indicated. If an abnormal condition such as rupture of the balloon occurs, an error code is indicated on the pressure displaying part  106 . 
     The tube  110  for supplying and sucking air to/from the balloon  60  is connected to the front side of the apparatus body  102 . At the connection part of the tube  110  and the apparatus body  102 , an anti-backflow unit  112  is provided for preventing backflow of body fluid in case of rupture of the balloon  60 . The anti-backflow unit  112  is configured by incorporating a filter for gas-liquid separation in a hollow disk-like case (not shown) which is detachably attached to the apparatus body  102 . Fluid flow into the apparatus body  102  is prevented by the filter. 
     On the hand switch  104 , various switches are provided. For example, a stop switch which is similar to the stop switch SW 2  on the apparatus body  102 , an on/off switch for directing pressurization/depressurization of the balloon  60 , and a pause switch for keeping pressure of the balloon  60  are provided. The hand switch  104  is electrically connected via a cord  130  to the apparatus body  102 . Although not shown in  FIG. 1 , the hand switch  104  is provided with an indicating part on which air supply or discharge conditions of the balloon  60  are indicated. 
     The balloon controlling apparatus  100  configured in the above described manner supplies air to the balloon  60  in order to expand it and keeps the expanded condition of the balloon  60  by controlling to keep air pressure at a constant value. In addition, the balloon controlling apparatus  100  sucks air from the balloon  60  in order to contract it and keeps the contracted condition of the balloon  60  by controlling to keep air pressure at a constant value. 
     The balloon controlling apparatus  100  is connected to a balloon-specific monitor  82 , on which the pressure value and the expanded and contracted conditions of the balloon  60  are displayed when the balloon  60  is expanded and contracted. The pressure value and the expanded and contracted conditions of the balloon  60  may be displayed on a monitor  50  in such a manner that they are superimposed on observed images of the endoscope  10 . 
     Then, the method of attaching the balloon  60  configured in the above described manner will be described. 
     At first, the insert part  12  is inserted through the cylinder body  62  of the balloon  60 , as shown in  FIGS. 2 ,  3 . Because the inner diameter D 3  of the balloon for attachment  66  is formed larger than the outer diameter D 2  of the insert part  12 , the insert part  12  can be easily inserted through the cylinder body  62 . 
     Next, the insert part  12  is inserted through the end  60 B of the balloon  60 , as shown in  FIG. 7 . When the cylinder body  62  is grasped and relatively moved toward the base end of the insert part  12 , the insert part  12  enlarges the end  60 B and thus the insert part  12  can be automatically inserted through the end  60 B. 
     After the balloon  60  is placed in a predetermined attachment position on the insert part  12 , thread is wound around the end  60 B of the balloon  60  so that the end  60 B of the balloon  60  is fixed to the insert part  12 . The end  60 B may be fixed to the insert part  12  by fitting a fixing ring and the like over the end  60 B. 
     Then, the end  64 B of the tube  64  is coupled to the end  63 B of the flow passage  63  of the cylinder body  62 , as shown in  FIG. 5 . Then, air is supplied to the flow passage  63  of the cylinder body  62  by the balloon controlling apparatus  100 . Thereby, air is supplied into the balloon for attachment  66  which is communicated with the flow passage  63 . Accordingly, the balloon for attachment  66  expands and presses the whole outer circumferential surface of the insert part  12  so that the cylinder body  62  is fixed to the insert part  12  via the balloon for attachment  66 , as shown in  FIG. 6 . A gap between the inner circumferential surface of the cylinder body  62  and the outer circumferential surface of the insert part  12  is sealed by the balloon for attachment  66 . Thus, the balloon  60  is fixed to the insert part  12  in such a manner that the ends  60 A,  60 B of the balloon  60  hermetically contact the insert part  12 . 
     After the balloon  60  is fixed to the insert part  12 , air is sucked from the balloon  60  by the balloon controlling apparatus  100  to contract the balloon  60 . In doing so, the balloon for attachment  66  does not contract because the cylinder body  62  is provided with the elastic piece  68 , and therefore the balloon for attachment  66  can be always kept expanded and fixed to the insert part  12 . 
     As described above, in the balloon  60  of this embodiment, the end  60 A is fitted over and fixed to the cylinder body  62 . Therefore, the insert part  12  can be easily covered with the end  60 A of the balloon  60  by inserting the insert part  12  through the cylinder body  62  and thus the task of attaching the balloon  60  can be easily performed. 
     In addition, according to this embodiment, because the flow passage  63  is formed in the cylinder body  62 , fluid can be supplied to the balloon  60  by connecting the tube  64  to the flow passage  63 . Therefore, it is not necessary to insert a tip of the tube  64  deeply into the balloon  60  and thus the task of attaching the balloon  60  can be easily performed and air-tightness in the end  60 A of the balloon  60  can be improved. 
     Further, according to this embodiment, because the cylinder body  62  is fixed to the insert part  12  by providing the balloon for attachment  66  on the inner side of the cylinder body  62  and expanding the balloon for attachment  66 , the fixing to the insert part  12  can be reliably performed even if the outer diameter dimension of the insert part  12  varies. Further, the feature of expanding and fixing the balloon for attachment  66  allows large clearance between the inner circumferential surface of the cylinder body  62  and the outer circumferential surface of the insert part  12 , so that the insert part  12  can be easily inserted through the cylinder body  62 . Moreover, when the balloon for attachment  66  is expanded and fixed to the insert part  12 , air-tightness between the insert part  12  and the cylinder body  62  can be kept by the balloon for attachment  66 . 
     Moreover, according to this embodiment, because the flow passage  63  of the cylinder body  62  is branched to communicate with both the balloon  60  and the balloon for attachment  66 , the balloon  60  and the balloon for attachment  66  are expanded with a common fluid. Therefore, the number of tubes  64  extending from the cylinder body  62  can be reduced. 
     In one exemplary method of operating the endoscope apparatus configured in the above described manner, the insert part  12  is inserted by pushing and the balloon  60  is expanded to fix the insert part  12  to a viscera (large bowel, for example), as required. Then, after the insert part  12  is drawn to simplify a tubular shape of the viscera, the balloon  60  is contracted to further insert the insert part  12  deeply into the viscera (large bowel, for example). For example, the insert part  12  is inserted from the anus of a subject and the balloon  60  is expanded to fix the insert part  12  to the bowel when the tip of the insert part  12  passes through the colon sigmoideum. Then, the insert part  12  is drawn to make the colon sigmoideum into a generally linear shape. Thereafter, the balloon  60  is contracted and the tip of the insert part  12  is inserted deeply into the bowel. In this way, the insert part  12  can be easily inserted deeply into the bowel. 
     Although a common fluid is supplied to both the balloon  60  and the balloon for attachment  66  by providing the branch passage  63 C of the flow passage  63  in the cylinder body  62  in the above described embodiment, this is not limiting. For example, by separately providing a tube which is communicated with the balloon for attachment  66 , fluid may be supplied to the balloon for attachment  66  independent of the balloon  60  so that the balloon for attachment  66  is independently expanded. In this case, it is preferable that fluid having larger viscosity is supplied to the balloon for attachment  66  than that of the balloon  60  or the balloon for attachment  66  is expanded with higher pressure than that of the balloon  60 . Alternatively, it is preferable that liquid (water, for example) is supplied to the balloon for attachment  66  while gas (air, for example) is supplied to the balloon  60 . In this way, the fixing to the insert part  12  by the balloon for attachment  66  can be done firmly and it is reliably prevented that fluid leaks from the balloon  60  when the balloon  60  is expanded. 
     Although the cylinder body  62  is covered with the end  60 A of the balloon  60  in the above described embodiment, the cylinder bodies  62 ,  62  may be covered with both ends  60 A,  60 B of the balloon  60 , as shown in  FIG. 8 . By covering the cylinder bodies  62  with both ends  60 A,  60 B in this way, the insert part  12  can be more easily inserted through the balloon  60  and the task of attaching the balloon  60  can be quickly performed. In the case of the balloon unit in  FIG. 8 , it is preferable that the balloons for attachment  66 ,  66  provided on both cylinder bodies  62 ,  62  are configured to couple to each other so that both balloons for attachment  66 ,  66  are simultaneously expanded and contracted. Further, in the case of the balloon unit in  FIG. 8 , it is preferable that the both cylinder bodies  62 ,  62  are configured to detachably engage to each other at their opposite end surfaces and the insert part  12  is inserted through in their engaged condition and the engagement is released after inserting. 
     Although the cylinder body  62  is fixed to the insert part  12  by the balloon for attachment  66  in the above described embodiment, the approach of fixing the cylinder body  62  to the insert part  12  is not limited to this, and a tape and the like may be wound for fixing. 
     Although the balloon  60  is formed in a generally cylindrical shape in the above described embodiment, the shape of the balloon  60  is not limited to this and any shape having a cylindrical end may be employed. Therefore, the balloon may be formed in a bag shape, for example. 
     Although the balloon  60  and the cylinder body  62  are configured as a balloon unit in the above described embodiment, this is not limiting. The balloon  60 , the cylinder body  62 , and the tube  64  may be configured as a balloon unit by integrally fixing the tube  64  to the cylinder body  62 , as shown in  FIG. 9 . In this case, an end of the tube  64  may be embedded and fixed in the cylinder body  62  and the flow passage  63  may be formed by the tube  64 . 
     In the balloon unit shown in  FIG. 9 , in contrast to the balloon unit shown in  FIGS. 2 to 6 , there is no balloon for attachment  66  and further the flow passage  63  of the cylinder body  62  is not branched and it is formed to penetrate in an axial direction of the cylinder body  62 . In such a balloon unit, the inner diameter D 4  of the cylinder body  62  may be configured to be somewhat larger than the outer diameter D 2  of the insert part  12 . In this way, the insert part  12  can be easily inserted through the cylinder body  62 . 
     When the balloon unit in  FIG. 9  is attached to the insert part  12 , it is preferable that a seal tape  69  is wound around the outer circumferential surface of the insert part  12  (the soft part  40 , for example) as shown in  FIG. 10 , so that the cylinder body  62  is fitted and fixed in the wound portion. In this way, a gap between the inner circumferential surface of the cylinder body  62  and the outer circumferential surface of the insert part  12  can be sealed by the seal tape  69 . In the balloon unit in  FIG. 10 , in order to prevent misalignment of the balloon  60 , it is preferable that a fluorine tape (not shown) or the like is wound over the ends  60 A,  60 B of the balloon  60  and the tube  64  to reliably fix to the insert part  12 . 
     Although the example of attaching the balloon unit for an endoscope apparatus according to the present invention to the insert part  12  of the endoscope  10  has been described in the above described embodiment, the object to which the balloon is attached is not limited to the endoscope, but may be any instrument used in the endoscope apparatus, such as an insert supporter for endoscope or an endoscope operative instrument.