A multiarticulated manipulator including a multijoint connecting mechanism having a plurality of arms, each arm having a joint capable of being bent in one plane and all the arms being connected with one another in positions spaced apart from one another by circumferential extent of 90 degrees. A plurality of wires are provided, each wire being connected to one of the arms and all the wires being supported and guided by wire guides and driven by a drive. The multiarticulated manipulator incorporated in a movable type remoted-controlled visual monitor system further includes a lens fixed to a forward end of the multijoint connecting mechanism, a fiberscope connected to the lens, and a movable member having the drive mounted therein and supporting the multijoint connecting mechanism, and a camera mounted in the movable member and connected to the lens through the fiberscope.

BACKGROUND OF THE INVENTION 
This invention relates to multi-articulated manipulators, and more 
particularly it is concerned with a multiarticulated manipulator having 
particular utility in use with a movable inspection apparatus. 
One type of multiarticulated manipulator is disclosed in Japanese patent 
application No. 74264/81. This type includes a soft mechanism having no 
segments whose forward end can be moved and bent in three dimensions by 
manipulating four wires attached to a forward end of a conical coil 
spring. It is impossible, however, to control the movement of other parts 
than the forward end of this mechanism, so that it is impossible to bend 
it in the form of a letter S. 
SUMMARY OF THE INVENTION 
This invention has as its object the provision of a multiarticulated 
manipulator capable of being bent in three dimensions. 
According to the invention, there is provided a multiarticulated 
manipulator comprising a multijoint connecting mechanism including a 
plurality of arms, each arm having a joint capable of being bent in one 
plane and all the arms being connected with one another in positions 
displaced from one another by an arbitrarily selected angle, a 
multiplicity of wires each provided to one of the arms, wire-guide means 
for supporting and guiding the wires, and drive unit means for driving 
each of the wires. 
Additional and other objects, features and advantages of the invention will 
become apparent from the description set forth hereinafter when considered 
in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A preferred embodiment of the multiarticulate manipulator in conformity 
with the invention will be described in detail by referring to FIGS. 1, 2, 
3A and 3B. As shown, the multiarticulated manipulator comprises a 
multiarticulated mechanism of seven degrees of freedom comprising eight 
cylindrical arms 1A-1H, and seven joints 2A-2G connecting the arms 1A-1H 
together and holding same in position, and secured to a fixed portion 5 as 
by bolts. More specifically, the arm section 1H is secured to the fixed 
portion 5 and the arms 1G, 1F, 1E, 1D, 1C, 1B and 1A are connected 
together in the indicated order from the arm 1H toward the forward end of 
the multiarticulated manipulator. The adjacent joints or the joints 2A and 
2B, for example, are arranged in positions displaced from each other by a 
circumferential extent of 90 degrees. More specifically, the arms 1B-1H 
are each formed at one end thereof with a pair of projections 20A and 20B 
which represent extensions of side walls of the arm sections. The joints 
2A-2G are each connected at opposite ends thereof to the projections 20A 
and 20B of the arms 1B-1H. The arms 1A-1H are each pivotably connected to 
one of the joints 2A-2G connected to the adjacent arms 1B-1H at ends 
thereof which are not formed with the projections 20A and 20B. The arms 
1A-1G are each inserted between the projections 20A and 20B of the 
adjacent arms. To this end, the projections 20A and 20B of arms 1A, 1C, 1E 
and 1G are displaced from those of the arms 1B, 1D, 1F and 1H 
respectively, and thus the joints 2A, 2C, 2E and 2G are displaced from the 
joints 2B, 2D, 2F and 2H respectively by a circumferential extent of 90 
degrees. By this arrangement, the arms 1A, 1C, 1E and 1G move in swinging 
movement upwardly and downwardly and the arms 1B, 1D, 1F and 1H move in 
swinging movement leftwardly and rightwardly in FIG. 1. 
FIG. 2 shows in detail the construction of one of the joints 2A-2G. As 
shown, the joint 2 comprises a pair of rods 7A and 7B, and a ring 10 
formed with an opening 10A. The pair of rods 7 are connected to a side 
wall of the ring 10 in diametrically opposed positions, and the rods 7A 
and 7B are each formed with a multiplicity of guide holes 8 for guiding 
wires for moving the arms in swinging movement. Each joint 2 is connected 
to the respective arm in such a manner that the ring 10 is located within 
the arm and the rods 7A and 7B extend through the side wall of the arm. 
The rods 7A and 7B are connected at their forward ends to the projections 
20A and 20B of the adjacent arm section. 
The arrangement of the wires for moving the arm sections in swinging 
movement will be described by referring to FIGS. 3A and 3B. FIG. 3A is a 
view as seen in the direction of arrows IIIA--IIIA in FIG. 1, and FIG. 3B 
is a view as seen in the direction of arrows IIIB--IIIB in FIG. 3A. In 
these figures, some wires are indicated by lines of the types different 
from those indicating other wires to clearly distinguish one wire from 
other wires. Seven wires are used to move the arms 1A-1G in swinging 
movement while the arm 1H remains stationary. Each wire is wound on a 
pulley of a pulse motor located in the fixed portion 5 and connected at 
opposite ends thereof to one end (the end having no projections) of the 
associated arm. The position in which the wire is connected to the 
respective arm is displaced by a circumferential extent of 90 degrees from 
the joint serving as a pivot for the swinging movement of the arm. 
Connection of the wires will be explained by referring to a wire 3C shown 
in FIG. 1 in which the wire 3C is wound on a pulley 4C of a pulse motor 
and connected at opposite ends thereof to the arm 1C. The pulley 4C is 
connected to the pulse motor through a speed reducing gearing, not shown. 
To facilitate explanation, the wire 3C will be described as being composed 
of a wire run 3C.sub.1 extending from the pulley 4C to one end of the wire 
3C, and a wire run 3C.sub.2 extending from the pulley 4C to the other end 
thereof. Referring to FIGS. 3A and 3B, the wires 3A, 3B, 3D, 3E, 3F and 3G 
subsequently to be described shall each be described as being composed of 
wire runs 3A.sub.1, 3B.sub.1, 3D.sub.1, 3E.sub.1, 3F.sub.1 and 3G.sub.1 
extending from the pulley to one end of the respective wire, and wire runs 
3A.sub.2, 3B.sub.2, 3D.sub.2, 3E.sub.2, 3F.sub.2 and 3G.sub.2 extending 
from the pulley to the other end thereof, respectively, as is the case 
with the wire 3C. The wires 3A-3G are all located within the arms. 
The wire run 3C.sub.1 extends through one of the guide holes 8 of the rod 
7A of each of the joints 2G, 2F, 2E and 2D and is connected to the arm 
section 1C at a point 6C.sub.1, and the wire run 3C.sub.2 extends through 
one of the guide holes 8 formed at the rod 7B of each of the joints 2G, 2F 
and 2D and is connected to the arm section 1C at a point 6C.sub.2. 
Other wires will be described by referring to FIGS. 3A and 3B. Although not 
shown, the wires 3A, 3B, 3D, and 3E-3G are each wound on a pulley of a 
respective pulse motor located in the fixed portion 5. 
The wire run 3A.sub.1 extends through one of the guide holes 8 formed at 
the rod 7A of each of the joints 2G, 2F . . . and 2B and is connected to 
the arm section 1A at a point 6A.sub.1. The wire run 3A.sub.2 extends 
through one of the guide holes 8 formed at the rod 7B of each of the 
joints 2G, 2F . . . and 2B and is connected to the arm 1A at a point 
6A.sub.2. The wire run 3B.sub.1 extends through one of the guide holes 8 
formed at the rod 7A of each of the joints 2G, 2F . . . 2C and is 
connected to the arm 1B at a point 6B.sub.1. The wire run 3B.sub.2 extends 
through one of the guide holes 8 formed at the rod 7B of each of the 
joints 2G, 2F . . . and 2C and is connected to the arm 1B at a point 
6B.sub.2. The wire run 3D.sub.1 extends through one of the guide holes 8 
formed at the rod 7A of each of the joints 2G, 2F and 2E and is connected 
to the arm 1D at a point 6D.sub.1. The wire run 3D.sub.2 extends through 
one of the guide holes formed at the rod 7B of each of the joint 2G, 2F 
and 2E and is connected to the arm 1D at a point 6D.sub.2. The wire run 
3E.sub.1 extends through one of the guide holes 8 formed at the rod 7A of 
each of the joints 2G and 2F and is connected to the arm section 1E at a 
point 6E.sub.1. The wire run 3E.sub.2 extends through one of the guide 
holes 8 formed at the rod 7B of each of the joints 2G and 2F and is 
connected to the arm section 1E at a point 6E.sub.2. The wire run 3F.sub.1 
extends through one of the guide holes 8 formed at the rod 7A of the joint 
2G and is connected to the arm section 1F at a point 6F.sub.1. The wire 
run 3F.sub.2 extends through one of the guide holes 8 formed at the rod 7B 
of the joint 2G and is connected to the arm 1F at a point 6F.sub.2. The 
wire run 3G.sub.1 is directly connected from the pulley to the arm section 
1G at a point 6G.sub.1, and the wire run 3G.sub.2 is directly connected 
from the pulley to the arm section 1G at a point 6G.sub.2. 
Each of the guide holes 8 formed at the rods 7A, 7B of the joints 2 allows 
only one wire, not two or more than two wires, to extend therethrough. To 
this end, the guide holes 8 formed at the rods 7A, 7B of the joints 2 vary 
in number. More specifically, the rods 7A and 7B of the joint 2G are each 
formed with six guide holes 8; the rods 7A ahd 7B of the joint 2F are each 
formed with five guide holes; the rods 7A and 7B of the joint 2E are each 
formed with four guide holes 8; the rods 7A and 7B of the joint 2D are 
each formed with three guide holes 8; the rods 7A and 7B of the joint 2C 
are each formed with two guide holes 8; and the rods 7A and 7B of the 
joint 2B are each formed with one guide hole 8. The rods 7A and 7B of the 
joint 2A have no guide holes. 
The arrangement of the wire runs are such that the wire runs for operating 
the foremost arm extend through the guide holes 8 remote from the ring 10 
and the guide holes 8 through which the wire runs extend are nearer to the 
ring 10 or the center of the joint when the arm to which the wire runs are 
connected becomes nearer. A pair of wire runs for operating the same arm 
extend through the guide holes 8 disposed symmetrically with respect to 
the ring 10 at the center of the joint 2. The reason why the wire runs 
extend through the guide holes 8 nearer to the ring 10 of the joint 2 as 
the arm to which the wire runs are connected becomes nearer is because 
this enables the range of swinging movement of the arm section to be 
increased. The wire runs extending between the joint for moving the arm 
section for up-and-down swinging movement and the joint for moving the arm 
section for left- and right swinging movement are trained such that, of 
the multiplicity of wire runs trained between the adjacent two joints 
located parallel to each other, those wire runs designed to operate the 
arm sections nearer to the forward end of the multiarticulated mechanism 
extend through the guide holes which are more remote from the center of 
the joints or are located on the outer side of the joints and those wire 
runs which are designed to operate the arm sections farther from the 
forward end of the multiarticulated mechanism extend through the guide 
holes nearer to the center of the joints or are located on the inner side 
of the joints. Thus the multiarticulated mechanism is twisted in such a 
manner that the adjacent joints are displaced from each other by a 
circumferential extent of 90 degrees. 
Operation of moving the arms in swinging movement will be described. Each 
arm is moved in swinging movement by actuating the associated pulse motor 
located in the fixed position 5. 
The operation will first be described by referring to the arm section 1C. 
Upon rotating the pulley 4C of the pulse motor in the direction of an 
arrow Q in FIG. 1, the wire run 3C.sub.1 is pulled leftwardly in FIG. 1 to 
shift the wire run 3C.sub.2 rightwardly in FIG. 1. As the wire runs 
3C.sub.1 and 3C.sub.2 move as aforesaid, the arm 1C moves in swinging 
movement about the joint 2C in the direction of an arrow P. When it is 
desired to move the arm 1C in swinging movement in a direction opposite 
the direction of the arrow P, one only has to rotate the pulley 4C in a 
direction opposite the direction of the arrow Q. The angle of swinging 
movement of the arm 1C is detected by a position detector, not shown, 
connected to the pulse motor. 
Other arm sections than the arm section 1C described hereinabove can be 
moved in swinging movement by driving the associated pulse motors and 
rotating the pulleys in a direction in which the arms are desired to move 
in swinging movement. The angle of swinging movement of each arm is 
detected by a position detector connected to each pulse motor. The 
position of the forward end of the multiarticulated manipulator can be 
determined by taking into consideration the distances between the joints 
as the angles of swinging movements of the arms detected by the respective 
position detectors are inputted to a computer. To avoid loosening of the 
wire runs, the pulleys and the pulse motors are pulled by means of tension 
reels and tension rods. 
The most important feature of the embodiment of the multiarticulated 
manipulator shown in FIG. 1 is that even if one arm is moved in swinging 
movement about an arbitrarily selected joint, the wire runs extending 
between such joint and the joint adjacent thereto remain unchanged in 
length. For example, assume that the arm 1G is moved in up-and-down 
swinging movement about the joint 2G in FIG. 3B. The arm 1G will be bent 
at one point of the joint 2G, so that the length of the wire runs between 
the joint 2G and the adjacent joint 2F remains unchanged. This would mean 
that when an arm connected to a certain joint is moved, in swinging 
movement, no interference phenomenon would occur or the swinging movement 
of the arm would not cause other arms to move in swinging movement about 
other joints. In the embodiment shown and described hereinabove, the 
arrangement that the guide holes 8 are formed at the rods 7A and 7B of the 
joints has the effect of avoiding the occurrence of the interference 
phenomenon. Thus, it is possible to obtain accurate information on the 
position of the forward end of the multiarticulated manipulator when an 
arbitrarily selected arm is moved in swinging movement. 
The embodiment shown and described hereinabove offers the advantage that 
the multiarticulated manipulator can be bent as desired in three 
dimensions. 
The multiarticulated manipulator constructed as aforesaid can be used for 
various purposes, including inspection and handling of articles. When it 
is desired to grip an object by means of the multiarticulated manipulator, 
one only has to attach a handling portion to the forward end of the arm 1A 
and connect wires and other means for effecting opening and closing of the 
handling portion by remote control to the fixed portion 5 through an 
opening 10A of the ring 10 shown in FIG. 2. 
FIGS. 4-7 show an example of the multiarticulated manipulator according to 
the invention as being incorporated in a movable type remote-controlled 
visual monitor system mounted in a container of a nuclear reactor. 
FIG. 4 schematically shows a movable type visual monitor system 
incorporating therein the multiarticulated manipulator according to the 
invention. As shown, the system comprises a movable member 21 suspended 
through a hanger 25 from a trolley chain 29 (see FIG. 5) mounted at a 
guide rail 22 in the form of a pouch slitted at its bottom in cross 
section, so that the movable member 21 can move along the guide rail 22 
which is located in the container of the nuclear reactor. The trolley 
chain 29 mounted at the guide rail 22 is in meshing engagement with a 
sprocket wheel 32 of a chain drive mechanism 31. The trolley chain 29 is 
endless as is the guide rail 22 at which it is mounted. The moving member 
21 travels along the guide rail 22 of the endless type as the trolley 
chain 29 is moved by the chain drive mechanism 31. However, since the 
moving member 21 pulls a cable 24, it is required to return to the 
starting point by moving in a reverse direction after making a round of 
the guide rail 22 and unable to make several rounds in the same direction. 
The trolley chain 29 has projections located equidistantly from one 
another and extending in the same direction through the slit at the bottom 
of the guide rail 22. A cable clamp 23 is bolted to each one of the 
projections. The cable 24 connected to the movable member 21 is payed out 
of a cable tank 38 as the movable member 21 travels along the guide rail 
22 and successively connected by a clamping mechanism 33 to the cable 
clamps 23 which are secured to the trolley chain 29, so that the cable 24 
moves in the same direction as the movable member 21 at the same speed. 
When the movable member 21 moves rearwardly, the cable 24 is successively 
disconnected from the cable clamps 23 and returned to the cable tank 38 by 
following the aforesaid process in reverse. A motor 35 is actuated when it 
is desired to pay the cable 24 out of the cable tank 38 and return same 
thereto. Actuation of the motor 35 allows the cable 24 to move between a 
pulley 36 connected to the motor 35 and a pulley 37 located in juxtaposed 
relation to the pulley 36. 34 is a guide reel for the cable 24. The cable 
24 extends from the cable tank 38 to a control panel 39 having a 
monitoring television receiver and operation buttons. 
A television camera 40 and the multiarticulated manipulator 41 shown in 
FIG. 1 are located anterior to the movable member 21. The construction of 
the multiarticulated manipulator 41 will be described by referring to 
FIGS. 6 and 7 in which parts similar to those shown in FIG. 1 are 
designated by like reference characters. As shown in FIG. 6, a 
multiplicity of pulse motors corresponding in number to the joints 2 are 
mounted in the movable member 21. FIG. 6 shows the pulse motors 9A, 9B, 9C 
and 9D for operating the joints 2A, 2B, 2C and 2D respectively which are 
supported on a support plate 11 in the movable member 21. Although not 
shown, the pulse motors for operating the joints 2E, 2F and 2G are 
supported on another support plate located in juxtaposed relation to the 
support plate 11 in the movable member 21. The pulse motors 9A, 9B, 9C and 
9D are connected to pulleys 4A, 4B, 4C and 4D respectively through speed 
reducing gearings, not shown. Although not shown, other pulse motors are 
also provided with respective pulleys. As shown in FIGS. 3A and 3B, six 
wires 3A-3G connected at opposite ends to the joints 2A-2G are connected 
to the respective pulleys. Of these six wires 6A-6G, the wires 3A, 3B, 3C 
and 3D are shown in FIG. 6. The multiarticulated manipulator 41 shown in 
FIG. 7 is of the same construction as the multiarticulated manipulator 
shown in FIG. 1 and its connection is shown in three dimensions. The 
arrangement of the wires and the manner in which the wires are connected 
to the arm sections in the multiarticulated manipulator 41 are similar to 
those in the multiarticulated manipulator shown in FIGS. 3A and 3B. Like 
the pulse motors of the multiarticulated manipulator shown in FIG. 1, the 
pulse motors of the multiarticulated manipulator 41 are each provided with 
a position detector, a tension reel and a tension rod. 
Located at the forward end of the multiarticulated manipulator 41 is a lens 
12 connected to a fiberscope 13 which extends through the openings 10a of 
the rings 10 of the joints 2A-2G to the movable member 21 to be connected 
to a television camera, not shown, mounted in the movable member 21 which 
is distinct from the television camera 40. The television camera 40 and 
the television camera connected to the fiberscope 13 produce video signals 
which are transmitted through the cable 24 to the control panel 39 and 
converted to visual images by the monitor television receiver 14 of the 
control panel 39. 
The chain drive mechanism 31 is actuated through the control panel 39 to 
cause the trolley chain 29 to move to allow the movable member 21 to 
travel along the guide rail 22. The television camera 40 converts visual 
images located ahead of the movable member 21 in a direction in which it 
moves to video signals. The operator can determine the position of the 
movable member 21 by converting the video signals to visual images which 
are shown on the monitoring television receiver 14. 
Operation of the multiarticulated manipulator 41 is performed by control 
signals transmitted from the control panel 39 to the movable member 21 
through the cable 24. More specifically, a drive signal is supplied from 
the control panel 39 to the pulse motor which drives the wire for 
operating the arm section desired to be moved in swinging movement. The 
pulse motor in the movable member 21 begins to rotate upon receipt of the 
drive signal. Rotation of the pulse motor causes the wire to move so as to 
thereby move the arm section in swinging movement about the joint. The 
swinging movement of each of the arms of the multiarticulated manipulator 
41 occurs in the same manner as described by referring to the swinging 
movement of each arm of the multiarticulated manipulator shown in FIG. 1. 
By moving the multiplicity of arm sections in swinging movement, it is 
possible to cause the forward end (the end at which the lens 12 is 
connected) of the multiarticulated manipulator 41 to move to any position 
as desired, such as a position behind pipings or equipment or in the bore 
of the piping or inside the equipment, which is beyond the range of visual 
observation of the television camera 40. Thus the multiarticulated 
manipulator 41 is able to produce visual images of portions which the 
television camera 40 has been unable to, even if it is of a pivotable 
type. Visual images are transmitted from the lens 12 to the television 
camera in the movable member 21 through the fiberscope 13, thereby 
facilitating monitoring of portions behind and between the pipings. The 
camera 40 has the function of enabling the movements of the 
multiarticulated manipulator 41 to be obtained as visual images and 
monitoring them. Although not shown, an illuminating lamp to aid in taking 
pictures is attached to the forward end of the multiarticulated 
manipulator 41. 
The multiarticulated manipulator 41 may be equipped with a thermometer, a 
vibrator and a radiation counter, in addition to the lens 12 and 
fiberscope 13. 
When the multiarticulated manipulator 41 according to the invention is 
incorporated in a movable type visual monitor system, it is possible to 
perform inspection of positions behind pipings or equipment in a container 
of a nuclear reactor of high radioactivity level which lie beyond the 
range of visual observation with the television camera 40, thereby 
increasing the area of the zone in which monitoring can be achieved by 
visual means. The end can be attained without laying the guide rail 22 in 
complicated zigzag fashion. As described hereinabove, the provision of the 
guide holes 8 for passing the wires therethrough at the rods 7A and 7B of 
the joints 2 renders the length of the wire runs constant between the 
arbitrarily selected adjacent two joints even if one arm is moved in 
swinging movement about one of such joints. Stated differently, no 
interference phenomenon occurs when an arm connected to one junction is 
moved in swinging movement, so that the swinging movement of such arm does 
not cause other arms connected to other joints to move in swinging 
movement. This enables the position of the forward end of the 
multiarticulated manipulator 41 to be determined with a high degree of 
accuracy when arbitrarily selected arms are moved in swinging movement. 
This characteristic makes the multiarticulated manipulator 41 very 
advantageous for use with a remote-controlled visual monitor system in 
which it is essential to correctly determine the position in which 
inspection is being performed. In the event that any abnormal condition 
exists in the piping, for example, it is possible to determine the 
location of the flaw accurately and carry out repair readily. 
FIG. 8 shows a modification of the joints of the multiarticulated 
manipulator according to the invention. As shown, the joint 15 is formed 
with the guide holes 8 at the ring 10, not at the rods 7A and 7B as in the 
embodiment shown in FIG. 2, and rods 7C and 7D with no guide holes are 
connected to the ring 10 with the guide holes 8. The wires for operating 
the arms of the multiarticulated manipulator each extend through one of 
the guide holes 8 of the joint 15. The multiarticulated manipulator having 
the joints 15 can also be bent readily in three dimensions. However, in 
the multiarticulated manipulator provided with the joints 15, when an arm 
connected to an arbitrarily selected joint is moved in swinging movement, 
the arms adjacent such arm might be caused to move slightly by the 
interference phenomenon about the joints to which they are connected. Thus 
the accuracy with which the position of the forward end of the 
multiarticulated manipulator might slightly be reduced. 
From the foregoing description, it will be appreciated that the 
multiarticulated manipulator according to the invention can be bent 
readily in three dimensions and lends itself to use with a 
remote-controlled visual monitor system.