This invention relates to an endoscope in which an endless belt is guided around via the interior and the exterior of an insertion tube of the endoscope and this endless belt is turned in contact with the body cavity wall surface, thereby enabling to insert the endoscope quickly. The endless belt is guided around between a hole formed at the forward end portion of the insertion tube and a control portion at the proximal end of the insertion tube in a manner to be partially exposed to the outside of the insertion tube, while, a drive means for turning the endless belt is provided in the control portion.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an endoscope utilized for the diagnosis and 
inspection of a living body, and mainly, a body cavity and the interior of 
a hollow organ in a human body. 
2. Description of the Prior Art 
Heretofore, there have been widely utilized fiber scopes for diagnosis and 
inspection of a living body, and mainly, a body cavity and the interior of 
a hollow organ in a human body such for example as the interiors of an 
upper digestive tract from a gallet through a stomach to a duodenum, a 
small intestine and a large intestine, and as apparatuses for medical 
treatment. 
However, since the fiber scope of the type described is to be directly 
inserted into a human body through a body cavity, various troubles may 
occur when the fiber scope is inserted into an organ disposed in a deep 
portion of the body. When a fiber scope for the small intestine is to be 
inserted into the small intestine through an oral cavity or an anus for 
example, if the fiber scope is pushed in, then the fiber scope does not 
advance in the small intestine, because the small intestine is afloat on a 
mesentery. Then, the small intestine advances together with the fiber 
scope, and, if the fiber scope is further forcedly pushed in, then there 
may be a danger of breaking the small intestine. On the other hand, when a 
fiber scope for the large intestine is inserted through the anus, if the 
fiber scope is forcedly pushed into the large intestine, then a sigmoid 
colon located upwardly of a rectum may be broken. 
Therefore, except for the above-described method of forcedly inserting the 
fiber scope into the body, there have heretofore been practised methods of 
insertion including a sonde method of inserting the fiber scope through 
the utilization of peristaltic motion of the intestines, a rope-way 
method, in which a string having a diameter of about 2 mm is swallowed by 
a patient and a fiber scope is inserted by drawing the string discharged 
by the patient the next day, and the like. However, both the sonde method 
and the rope-way method are disadvantageous in that a long period of time 
is required for the insertion of the fiber scope and the insertion causes 
pains to the patient for that long period of time. 
Now, in the specification of French Patent No. 2481915, there is disclosed 
an apparatus having a so-called self-running device, in which a pulley is 
provided on the outer surface portion of a head of fiber scope and a belt 
being in frictional contact with the body wall surface is guided around 
this pulley. 
According to the French Patent, the insertion of the head can be made for a 
short period of time by the turning of the belt. However, since the pulley 
is considerably projected from the outer surface of the head, with the 
result that the head becomes large sized, so that the pains suffered by 
the patient should not necessarily be alleviated. Moreover, the apparatus 
according to the French Patent is disadvantageous in that, when the fiber 
scope is inserted into a portion to be inspected such as a sigmoid colon, 
a mucous coat of the intestine is liable to be hurt, thus resulting in 
unsatisfactory safetly. 
In Japanese Patent Kokai (Laid-Open) No. 22024/83, there is disclosed a 
fiber scope, in which a pulley for supporting a belt being in frictional 
contact with the body wall surface is provided in a head and the belt is 
extended through a hole formed in this head portion. 
In the fiber scope according to the Japanese Patent Kokai (Laid-Open) No. 
22024/83, the provision of the pulley in the head makes it possible to 
lessen the value of the aforesaid projection. However, the provision of a 
drive means for turning the pulley in the head increases the head 
accordingly, whereby the pains suffered by the patient still cannot be 
removed. 
SUMMARY OF THE INVENTION 
The present invention has as its object the provision of an endoscope which 
can be readily inserted for a short period of time without giving great 
pains to a patient. 
To achieve the above-described object, the present invention contemplates 
that at least one endless belt is guided around via the interior and the 
exterior of an insertion tube and a head in such a manner that the endless 
belt exposed from the outer surfaces of the insertion tube and the head is 
contacted with the outer surface of the insertion tube, and a drive means 
for turning this endless belt is provided at the proximal end of the 
insertion tube, to thereby lessen the diameters of the insertion tube and 
the head.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Description will hereunder be given of the embodiments of the present 
invention with reference to the drawings. 
FIG. 1 shows the general arrangement of the first embodiment of the 
endoscope according to the present invention. 
In a fiber scope 1, an ocular poriton 4 is integrally formed on the 
proximal end portion of an insertion tube 2 formed into a small diameter 
tube made of a flexible material through a control portion 3. 
As shown in FIG. 2, the insertion tube 2 is formed at the forward end 
thereof with a head 5, provided on the outer surface, on one side and in 
the longitudinal direction thereof with a dovetail grooveshaped guide 
groove 6 (Refer to FIG. 3), and further, contains therein, in the 
longitudinal direction thereof, two light guides 7, in each of which a 
plurality of optical fibers are bundled, an image guide 8, in which a 
plurality of optical fibers are bundled, an endless belt 9 being partially 
turned along the guide groove 6 and made of a flexible material, a forceps 
guide tube, not shown, an air-water feed tube, and the like. As shown in 
FIG. 3, the head 5 is provided therein with a belt guide hole 10 for 
leading the endless belt 9 to outside. Around the belt guide hole 10, 
there are provided projector holes 11 at positions corresponding to the 
forward ends of the light guides 7, a picture hole 12 at a position 
corresponding to the forward end of the image guide 8, a forceps hole 13 
at a position diagonal to this picture hole 12 and an air-water feed hole 
14 at a position adjacent to the picture hole 12, respectively. Inside the 
belt guide hole 10, there is provided a guide roller 15 for guiding the 
endless belt 9 from the outer end face of the head 5 to the guide groove 
6. Furthermore, the picture hole 12 is fitted therein with an objective 
lens 16 for focusing the rays from outside and causing the same to be 
incident on the image guide 8. 
Outside the control portion 3, there are provided a flexible connection 
tube 21 for connecting the light guides 7 to a light source device, not 
shown, a forceps insertion hole 23 for projecting a forceps 22 (Refer to 
FIG. 1) from the forceps hole 13 through a forceps guide tube of the 
insertion tube 2, an air-water feed hole portion 24 and an water suction 
hole 26 for flowing air and washing water out of the air-water feed hole 
14 through a water conveying tube of the insertion tube 2 and washing the 
objective lens 16, and a control knob 25 for flexing the forward end 
portion (head 5) of the insertion tube 2, respectively. Furthermore, 
inside the control portion 3, there are provided two guide rollers 27A, 27 
for guiding the proximal end of the endless belt 9 and a drive means 28 
for turning the endless belt 9, respectively. The drive means 28 comprises 
a pair of clamp rollers 29, 30 for clamping the opposite surfaces of the 
endless belt 9 and a motor 31 for driving one 30 of the clamp rollers. 
Inside the ocular portion 4, there is provided an ocular lens 32 for 
focusing the rays emitted from the proximal end of the image guide 8, 
whereby an image made to focus at the forward end of the image guide 8 by 
the objective lens 16 is transmitted to the proximal end of the image 
guide 8 through the optical fibers of the image guide 8 and inspected 
through the ocular lens 32. 
The method of use will now be described. To insert the fiber scope 1 
through a body cavity, e.g., an anus, firstly one 30 of the clamp rollers 
is rotated by the driving of the motor 31 to thereby turn the endless belt 
9 in a direction indicated by an arrow mark as shown in FIG. 2. When the 
forward end of the insertion tube 2 is inserted through an anus in this 
state, the endless belt 9 exposed from the forward end portion of the 
insertion tube 2 comes into contact with a part of a body cavity wall 51 
as shown in FIG. 2, so that the insertion tube 2 can be inserted along the 
body cavity wall 51 due to the contact resistance. Thus, even if the 
portion of the body cavity is curved or is a comparatively weak mucosa 
layer such as an intestine, the forward end of the insertion tube 2 is 
guided along the body cavity wall, so that the insertion tube 2 can be 
inserted into a deep portion of the interior of the body with no body 
cavity wall being broken. 
In consequence, according to this embodiment, the endless belt 9 partially 
exposed from the outer surface of the forward end portion to the proximal 
end portion of the fiber scope 1 is brought into contact with the fiber 
scope 1 in a manner to be slidable on the outer surface of the insertion 
tube 2 and the drive means 28 for turning the endless belt 9 is provided 
in the control portion 3, so that the outer diameter of the insertion tube 
2, particularly, the outer diameter of the head 5 can be reduced. 
Moreover, when the forward end of the fiber scope 1 is inserted through a 
body cavity in the conditions where the endless belt 9 if turned by the 
drive means 28, the fiber scope 1 is inserted into the body, while being 
guided along the body cavity wall 51, due to the contact resistance caused 
between the endless belt 9 and the body cavity wall 51, so that the fiber 
scope 1 can be inserted quickly and with no considerable pains given to 
the patient. Further, according to this embodiment, the endless belt 9 is 
exposed over the total length of the outer surface of the insertion tube 
2, whereby, the larger the length of insertion of the insertion tube 2 
into the body becomes, the larger the contact surface between the body 
cavity wall and the endless belt 9 becomes, so that the fiber scope 1 can 
be readily inserted into the deep portion in the body with no excessively 
large contact resistance given to a part of the body cavity wall. Since 
the endless belt 9 is guided by the guide groove 6, the endless belt 9 is 
not separated from the insertion tube 2 even when the insertion tube 2 is 
curved due to the curving of the body cavity wall 51, so that the endless 
belt 9 can be held in contact with the body cavity wall 51 at all times, 
thus avoiding damages given to the body cavity wall and an unsatisfactory 
movement of the endless belt 9. 
Description will hereunder be given of the second embodiment of the present 
invention. Same reference numerals are used to designate same or similar 
constituent parts, so that explanation will not be duplicated or will be 
simplified. 
FIGS. 4 through 7 show the second embodiment of the endoscope according to 
the present invention. 
The endoscope 1 in the second embodiment is of such an arrangement that an 
image pickup element is provided in the head, and an image pickup signal 
detected by the image pickup element is led out of the insertion tube to 
outside through a lead wire for example, whereby the image guide 
comprising a plurality of optical fibres as shown in FIG. 1 is removed, so 
that both the insertion tube and the head can be reduced in outer 
diameter. 
Referring to FIGS. 4, 5, and 6 the forward end portion of the insertion 
tube 2 is flexibly provided thereon with the head 5 through a stepped 
portion. The head 5 is provided at the forward end face thereof with the 
picture hole 12, the two projector holes 11, the forceps hole 13 and the 
air-water feed hole 14, respectively, substantially similarly to the 
preceding embodiment. In the head 5, there are provided the objective lens 
16 and the image pickup element 18, both of which are faced to the picture 
hole 12, and a light source 19 such as a lamp is faced to the projector 
hole 11, respectively. In this case, for example, charge-coupled devices 
are used as the image pickup element 18. On the other hand, as shown in 
FIG. 7, in the insertion tube 2, there are formed two dovetail 
groove-shaped guide grooves 6 on the insertion tube 2 at circumferential 
positions spaced 180.degree. apart from each other on the outer surface 
and in the longitudinal direction of the insertion tube 2, and there are 
housed two endless belts 9, a lead wire for transmitting a picture signal 
detected by the image pickup element 18 to an external device such as a 
monitoring device, a lead wire for supplying an electric power to the 
light source 19, a forceps guide tube, the air-water feed tube and the 
like, respectively. The endless belts 9 are passed through the insertion 
tube 2, led out of the stepped portion at the forward end of the insertion 
tube 2 to outside, and guided around the insertion tube 2 to the proximal 
end thereof along the guide grooves 6 thereon. 
In the control portion 3, there is provided a drive means 36 for turning 
the respective endless belts 9 in directions opposite to each other. The 
drive means 36 comprises two pairs of guide rollers 37, 38 clampingly 
holding the opposite surfaces of the proximal ends of the respective 
endless belts 9 and a motor 40 for turning the guide rollers 38 through a 
gear train 39 including bevel gears, spur gears and the like, to thereby 
turn the respective endless belts 9 in directions indicated by arrow marks 
in FIG. 5. 
The method of insertion of the insertion tube according to this embodiment 
is substantially similar to that according to the first embodiment. 
However, a difference from the first embodiment resides in that two 
endless belts disposed in the vertical direction are simultaneously 
brought into contact with the body cavity wall 51. 
The second embodiment described above has the following advantages in 
addition to the advantages of the first embodiment. 
Namely, since two endless belts 9 are provided at positions above and below 
the insertion tube 2 in the drawing, the contact area of the endless belts 
9 contacting the body cavity wall 51 can be increased, so that the period 
of time required for the insertion of the head 5 can be further decreased. 
Since a picture signal detected by the image pickup element 18 is 
transmitted to outside through the lead wire for transmitting the picture 
signal, necessity for providing the image guide, in which the plurality of 
optical fibres are bundled, is eliminated, and a space for incorporating 
the endless belts 9 can be made in the insertion tube 2, whereby the 
insertion tube 2 can be reduced in diameter accordingly, so that the 
insertion of the insertion tube 2 and the head 5 into the body cavity can 
be smoothly effected. 
In working, there is no need for providing the endless belt 9 over the 
total length of the insertion tube 2, and instead, as shown in FIG. 8 for 
example, the endless belt 9 may be provided only at the forward end 
portion of the insertion tube 2 (In order to avoid giving damages to the 
intestinal wall, it is preferable that the length of the endless belt 
should be larger than one thirds of the total length of the insertion tube 
2). In this case, for example, if the rotation of the motor provided in 
the control portion 3 at the proximal end of the insertion tube 2 is 
transmitted to the clamp roller 30 on one side out of the clamp rollers 29 
and 30 clampingly holding the opposite surfaces of the endless belt 9 
through a flexible rotary shaft, then the endless belt 9 may be turned at 
the forward end portion. 
In the first embodiment, there has been described the arrangement, in which 
one endless belt is used, however, the number of the endless belts need 
not necessarily be limited to this, but, the arrangement includes the use 
of two or more endless belts. For example, when two endless belts are 
used, the endless belts, which have been led out to the outside of the 
insertion tube 2 from the guide hole 10 and directed to the proximal end 
of the insertion tube 2, are arranged to turn in directions opposite to 
each other substantially similarly to the second embodiment as shown in 
FIGS. 9 and 10. 
Furthermore, the shape of endless belt need not necessarily be limited to 
be flat, but, may be round or the like as shown in FIGS. 11 and 12. The 
endless belt 9 shown in FIG. 11 is formed into a substantially round belt 
formed with grooves on opposite sides and in the longitudinal direction of 
the endless belt 9, so that the endless belt 9 is reliably held in the 
guide grooves 6 to prevent the endless belt 9 from falling off. 
Further, in the above embodiment, there has been shown the embodiment, in 
which the endless belt 9 is slidably coupled into the guide grooves 6, 
however, projections 60 capable of holding the endless belt 9 from 
opposite sides thereof may be provided on the head 5 and at a plurality of 
positions at regular intervals and in the longitudinal direction of the 
insertion tube 2 as shown in FIG. 12. Furthermore, when the endless belt 9 
thus formed of the round belt is used, if the respective pulleys are 
formed into substantially spool-shapes, then the endless belt may be 
perfectly prevented from falling off inside and outside of the insertion 
tube 2, and also, the insertion tube 2 may be prevented from moving in a 
zigzag fashion, while being inserted. 
Furthermore, when three or more endless belts 9 are provided, if the 
endless belts 9 are provided at equiangular positions as centered about 
the insertion tube 2 as shown in FIGS. 13 and 14, then the insertion tube 
2 may be effectively prevented from moving in a zigzag fashion in the 
vertical and lateral directions. 
Except the arrangements shown in the abovedescribed embodiments, the drive 
means 28 and 36 may have arrangements as shown in FIG. 15 or 16. The drive 
means shown in FIG. 15 is of such an arrangemnet that gears 41 and 42 are 
provided at the forward end portion and the proximal end portion of the 
fiber scope 1, respectively, an endless belt 9 formed of a timing belt is 
guided around these gears 41 and 42, and one 41 of the gears is rotated by 
a motor 43. Furthermore, the drive means shown in FIG. 16 is of such an 
arrangement that a plurality of pulleys 44, 45, 46 and 47 are provided at 
the forward end portion and the proximal end portion of the fiber scope 1, 
one of the pulleys 45 is rotated by a motor 48 and a tensile force is 
given to a belt portion between the pullys 46 and 47. A tension mechanism 
in this case comprises a pulley 49 contacting one surface of the endless 
belt 9 opposite to the other, which the pair of pulleys 46 and 47 contact, 
and a spring 50 biasing the pulley 49 toward the pair of pulleys 46 and 
47. 
In addition, FIGS. 8 through 16 show modifications based on the specific 
form of the endoscope shown in the first embodiment, by which it is 
intended to omit the substantially duplicated drawings. Needless to say, 
the arrangements shown in these drawings are applicable to the second 
embodiment. 
As has been described hereinabove, the present invention can provide the 
endoscope wherein the insertion tube and the head are reduced in diameter, 
whereby the endoscope can be smoothly and quickly inserted into a human 
body without giving considerable pains to a patient.