Joint mechanism for structural members

A passage communication member is fitted in a first passage in a structural member, and has a head which is mounted in a slot in another structural member. The first passage in the structural member and a passage in the other structural member are held in communication with each other through a through hole that is defined in the passage communication member. Alternatively, a first engaging member is inserted in a recess defined in a structural member, and a second engaging member is retained in a slot in another structural member. When the first and second engaging members are coupled to each other by a fastening member, the structural members are firmly joined and fixed to each other.

TECHNICAL FIELD 
The present invention relates to a joint mechanism for joining structural 
members while keeping passages defined in the structural members in 
communication with each other when the structural members are to be 
assembled into a structural assembly. 
BACKGROUND ART 
The applicant of the present application has proposed an actuator which 
includes a drive means such as a motor or the like and a movable member 
that is displaceable by the drive means, the drive means and the movable 
member being accommodated in a recess in a structural member which 
comprises a substantially elongate columnar body, and also proposed a 
structural assembly (Japanese laid-open patent publications Nos. 5-69352, 
5-180295, 5-180296, and 5-180297). In the proposal, there has been used a 
term "structural member" which represents a concept including both an 
outer frame of an actuator and a columnar elongate member. The term will 
be used below as meaning the same concept. 
According to the technical ideas disclosed in the above publications, a 
plurality of structural members which are of substantially the same shape 
may be assembled by joint mechanisms into a structural assembly that has a 
desired function. 
One example of the joint mechanisms disclosed in the above publications is 
a locking member 2 for joining structural members as shown in FIG. 1 of 
the accompanying drawings. As shown in FIG. 1, one end of the locking 
member 2 is inserted into a hole 6 defined longitudinally in a structural 
member 4, and a head 8 on the other end of the locking member 2 is loosely 
fitted in a slot 10 defined in another structural member 4a. Then, a screw 
14 is threaded through a plate 12 transversely into the structural member 
4 until a tip end 16 of the screw 14 is held against a slanting surface 18 
of a notch defined substantially centrally in the locking member 2. The 
tip end 16 is of such a tapered configuration that when the screw 14 is 
threaded in, the tip end 16 presses the slanting surface 18, displacing 
the locking member 2 in the direction indicated by the arrow A in FIG. 3 
of the accompanying drawings. When the locking member 2 is displaced in 
the direction indicated by the arrow A, the head 8 of the locking member 2 
pulls an inner wall surface of the other structural member 4a also in the 
direction indicated by the arrow A. As a result, the structural members 4, 
4a are fixedly joined to each other substantially perpendicularly to each 
other as shown in FIGS. 2 and 3 of the accompanying drawings. The locking 
member 2 is normally biased in the direction indicated by the arrow B 
under resilient forces from a spring 19. 
The present invention has been made in relation to the above proposals. It 
is an object of the present invention to provide an improved joint 
mechanism for joining structural members while keeping passages defined in 
the structural members in communication with each other. 
Another object of the present invention is to provide a joint mechanism 
which joins structural members substantially in line or perpendicularly 
through slots defined longitudinally in the structural members, so that a 
structural assembly can simply be constructed of the joined structural 
members. 
Still another object of the present invention is to provide a joint 
mechanism which is capable of joining structural members angularly movably 
to each other at a freely selected angle between the joined structural 
members. 
DISCLOSURE OF THE INVENTION 
With a joint mechanism for joining structural members according to the 
present invention, a passage communication member is fitted in a passage 
in one of the structural members, and has a head which is mounted in a 
slot in the other of the structural members. The passage in one of the 
structural members and a passage in the other of the structural members 
are held in communication with each other through a through hole that is 
defined in the passage communication member. Alternatively, a first 
engaging member is inserted in a recess defined in one of the structural 
members, and a second engaging member is retained in a slot in the other 
of the structural members. When the first and second engaging members are 
coupled to each other by a fastening member, the structural members are 
firmly joined and fixed to each other.

BEST MODE FOR CARRYING OUT THE INVENTION 
Embodiments of the present invention will be described below in detail with 
reference to the accompanying drawings. 
As shown in FIG. 4, structural members 20, 20a are in the form of 
substantially identical, elongate columnar bodies. The structural member 
20 has substantially identical slots 22 of substantially T-shaped cross 
section which are defined respectively in outer side surfaces thereof. 
Since the structural members 20, 20a are substantially identical to each 
other in structure, the structural member 20 will be described below, and 
the structural member 20a will not be described below. 
Each of the slots 22 has inlet edges which have respective substantially 
V-shaped grooves 24 defined therein that extend along the slot 22. A 
substantially channel-shaped cover 23 is mounted in the slot 22 with teeth 
25 of the cover 23 engaging in the respective V-shaped grooves 24. Each of 
the slots 22 has an enlarged portion 26 which is spread from the inlet 
edges in directions perpendicular to the axis of the structural member 20, 
and a cavity 28 which is constricted inwardly from the enlarged portion 26 
and extends to a flat bottom 27. The structural member 20 also has a pair 
of substantially circular recesses 29a, 29b (mounting recesses) defined in 
its upper surface closely to respective opposite ends thereof and 
communicating with the slot 22 in the upper surface. 
The structural member 20 further includes a first passage 30 of large 
diameter defined therein which extends along the axis thereof, second 
passages 32a.about.32d of small diameter defined therein near the four 
corners thereof and extending in the longitudinal direction of the 
structural member 20, and third passages 34a.about.34d defined therein 
which extends along the axis thereof, the third passages 34a.about.34d 
being positioned between the first passage 30 and the second passages 
32a.about.32d. A plug 36 (see FIG. 4) is mounted in an end of the 
structural member 20a and closes the first passage 30. The structural 
member 20a has a hole 38 (see FIG. 5) defined therein in communication 
with the first passage 30. 
A joint mechanism for joining structural members according to an embodiment 
of the present invention includes a passage communication member 42 (see 
FIGS. 4 and 5) having a through hole 40 defined therein which provides 
communication between the first passage 30 in the structural member 20 and 
the first passage 30 in the other structural member 20a. As shown in FIG. 
4, the joint mechanism also has a first engaging member 44 inserted in the 
recess 29a (29b) in the structural member 20, a second engaging member 46 
retained in one of the slots 22 in the structural member 20a, and a bolt 
48 interconnecting the first engaging member 44 and the second engaging 
member 46. The structural members 20, 20a are joined to each other by 
mounting the first engaging member 44 in the structural member 20, 
mounting the second engaging member 46 in the structural member 20a, and 
then coupling the first engaging member 44 and the second engaging member 
46 to each other with the bolt 48. 
The passage communication member 42 comprises a tubular body 50 fitted in 
the first passage 30 extending axially in the structural member 20, and a 
head 54 having a projection 52 fitted in the hole 38 in the structural 
member 20a. The head 54 is of a substantially T shape and is fitted in the 
slot 22 in the structural member 20a. The tubular body 50 and the head 54 
are integrally formed with each other, and a seal 56 is mounted in an 
annular groove defined in the tubular body 50. An elastic seal 58 is 
mounted on a surface of the head 54 around the projection 52 and held 
against an inner wall surface of the slot 22. Under the resiliency of the 
elastic seal 58, the head 54 is pressed toward the structural member 20 to 
hold the passage communication member 42 in the slot 22 (see FIG. 5). 
The first engaging member 44 has a substantially circular profile 
complementary in shape to the recesses 29a, 29b, and has a rectangular 
hole 60 defined therein and a screw hole 61 defined therein which extends 
from the bottom of the rectangular hole 60 to an outer surface of the 
first engaging member 44. The second engaging member 46 has a 
substantially T-shaped head 62 on one end thereof which is held in the 
slot 22 and a threaded hole 64 defined in an opposite end remote from the 
head 62 for receiving the bolt 48 therein. The first and second engaging 
members 44, 46 should preferably be made of aluminum alloy, stainless 
steel, carbon steel, molybdenum steel, or the like, and manufactured by 
precision casting, precision (cold) forging, lost-wax process, metal 
powder injection sintering, or the like. The first and second engaging 
members 44, 46 thus produced have a high strength, require no substantial 
subsequent machining, and are light in weight and low in cost. 
The joint mechanism according to this embodiment, which is basically of the 
above structure, operates as follows: 
The substantially T-shaped head 54 of the passage communication member 42 
is inserted from an end of the structural member 20a into one of the slots 
22 therein while the longitudinal axis of the head 54 is being aligned 
with the longitudinal axis of the slot 22. After the head 54 is inserted, 
it is twisted about 90.degree. into locking engagement with an inner wall 
surface of the slot 22, and the projection 52 is fitted into the hole 38 
communicating with the first passage 30 (see FIG. 5). At this time, the 
seal 58 around the projection 52 elastically presses the inner wall 
surface of the slot 22, securing retaining the substantially T-shaped head 
54 in the slot 22. As a result, the passage communication member 42 is 
held in position in the slot 22 in the structural member 20a, with the 
tubular body 50 projecting out of the slot 22. Then, as shown in FIG. 4, 
the other structural member 20 is oriented substantially perpendicularly 
to the structural member 20a, and an end of the structural member 20 is 
brought toward the structural member 20a until the tubular body 50 is 
fitted into the first passage 30 in the structural member 20. Therefore, 
the first passage 30 in the structural member 20a and the first passage 30 
in the structural member 20 are held in communication with each other 
through the through hole 40 in the passage communication member 42. The 
seal 56 disposed around the passage communication member 42 fitted in the 
first passage 30 serves to hermetically seal the first passage 30. 
Thereafter, the first engaging member 44 is inserted into the substantially 
circular recess 29a in the structural member 20, and the head 62 of the 
second engaging member 46 is inserted from the end of the structural 
member 20a into the slot 22 therein. Then, the bolt 48, placed in the slot 
22 in the structural member 20, is threaded through the screw hole 61 in 
the first engaging member 44 into the threaded hole 64 in the second 
engaging member 46. As the bolt 48 is threaded in, the head 62 of the 
second engaging member 46 is pulled in the direction indicated by the 
arrow X in FIG. 6. As a consequence, the structural member 20a is 
displaced toward the structural member 20, and they are firmly joined to 
each other. 
The joint mechanism according to this embodiment is thus effective in 
firmly joining the structural members 20, 20a to each other while keeping 
the first passages 30 in the structural members 20, 20a in communication 
with each other. 
FIG. 7 shows an assembly of plural structural members joined by joint 
mechanisms according to this embodiment. 
As shown in FIG. 7, the assembly, generally denoted by 100, comprises a 
plurality of structural members 102 which form an assembly skeleton, a 
plurality of actuators 104, 106, 108, 110, 112, 114, 116, 118, 120, a 
plurality of balancers 122, 124, 126 disposed parallel to the actuators 
106, 112, 116, first and second working tables 128, 130, a plurality of 
workpieces 132, a plurality of workpiece holding plates 134, a plurality 
of movable bodies 136, 138, 140, 142, 144, 146, 148 combined with the 
actuators, a suction pad 150 and a mechanical hand 152 which function as 
workpiece gripping means, and a plurality of cylinders 156 having 
respective projecting cylinder rods 154. Sequencers 158, 160 with 
programming boards, which function as actuator controllers, are mounted on 
the upper surface of one of the structural members 102. Some of the 
structural members 102 are assembled in substantially rectangular 
structures each including a diagonal structural member 102 whose opposite 
ends are associated with joint members 162, 164 for reinforcing joined 
regions. Some of the structural members 102 are joined in line with each 
other by joint mechanisms 165, and some of the structural members 102 are 
substantially perpendicularly joined by joint mechanisms 167. 
The first working table 128 will mainly be described in detail below. 
The actuator 106 is vertically mounted on and substantially perpendicularly 
joined to the actuator 104 which is substantially horizontally arranged. 
The balancer 122 is disposed parallel to the actuator 106. The actuator 
106 serves to move the actuator 108 fixed to the movable body 138 thereof 
in substantially vertical directions. A cylinder 166, to which the suction 
pad 150 is attached, is supported on the movable body 140 of the actuator 
108 connected perpendicularly to the actuator 106. The cylinder 156 is 
attached to the movable body 142 of the actuator 110, and the cylinder rod 
154 thereof serves to position a workpiece 132. Motor boxes 168 are 
disposed respectively in the actuators 104, 106, 108, 110, 112, 114, 116, 
118, 120 and have respective upper surfaces lying flush with, but not 
projecting from, the upper surfaces of these actuators. 
The first working table 128 operates as follows: Compressed air is supplied 
to the cylinder 166 coupled to the actuator 108 through fluid passages 
(the first, second, and third passages 30, 32a.about.32d, 34a.about.34d) 
in the structural members 102. Under the pressure of the supplied 
compressed air, the cylinder rod of the cylinder 166 is displaced 
downwardly, and a workpiece 132 placed on the workpiece holding plate 134 
is attracted by the suction pad 150. Compressed air is supplied again to 
the cylinder 166, displacing the cylinder rod upwardly, and the movable 
body 136 of the actuator 104 is moved. The actuator 104 is inactivated 
when the workpiece 132 attracted by the suction pad 150 reaches a position 
above a desired position on the workpiece holding plate 134. Then, the 
movable body 138 of the actuator 106 is moved downwardly until the 
attracted workpiece 132 is inserted into a desired hole in the workpiece 
holding plate 134. At this time, the cylinder rod 154 of the actuator 110 
may be displaced to position the workpiece 132 so that the workpiece 132 
can reliably be inserted into the desired hole in the workpiece holding 
plate 134. 
The joint mechanism according to this embodiment is not limited to the 
application to the assembly 100, but may be applied to various assemblies 
of structural members. 
A joint mechanism for joining structural members according to another 
embodiment of the present invention will be described below with reference 
to FIGS. 8 through 11. Those parts of the joint mechanism and structural 
members in this and other embodiments which are identical to those in the 
previous embodiment are denoted by identical reference characters, and 
will not be described in detail below. 
The joint mechanism according to the embodiment shown in FIGS. 8 through 
11, which is used to join the structural members 20, 20a, comprises a pair 
of substantially rectangular adapter blocks 238a, 238b of substantially 
identical shape, a first knuckle 240 coupled to the adapter block 238a, a 
second knuckle 242 coupled to the adapter block 238b, and a pair of 
washers 250a, 250b disposed between the first and second knuckles 240, 242 
and supported on a shaft 248 extending through holes 244, 246 that are 
defined in the first and second knuckles 240, 242. Covers 252a, 252b are 
attached respectively to opposite side surfaces of the first knuckle 240. 
The rectangular adapter blocks 238a, 238b have side surfaces shaped and 
dimensioned substantially identically to the ends of the structural 
members 20, 20a, and lying flush with the structural members 20, 20a. 
Each of the adapter blocks 238a, 238b has attachment holes 256a.about.256d 
defined therein near respective four corners thereof for insertion of long 
screws 254 therethrough, and a through hole 260 defined substantially 
centrally therein for insertion of a bolt 258 therethrough. When the long 
screws 254 are threaded through the attachment holes 256a.about.256d of 
the adapter blocks 238a, 238b into the second passages 32a.about.32d, 
which are internally threaded, defined in the corners of the structural 
members 20, 20a that are held in line with each other, the adapter blocks 
238a, 238b are fastened to the corresponding ends of the structural 
members 20, 20a. 
The adapter blocks 238a, 238b have respective sets of straight ridges 262 
on their surfaces which are held against the ends of the structural 
members 20, 20a. The ridges 262 are inserted in the respective cavities 28 
of the slots 22 in the structural members 20, 20a when the adapter blocks 
238a, 238b are joined to the ends of the structural members 20, 20a. The 
adapter blocks 238a, 238b also have respective substantially circular 
recesses 264 defined in their surfaces remote from the straight ridges 262 
for receiving the bottoms of the first and second knuckle members 240, 
242. The circular recess 264 has a bottom having a diameter large enough 
for the first knuckle 240 or the second knuckle 242 to be angularly moved 
in the circular recess 264 about the bolt 258. The adapter blocks 238a, 
238b also have threaded holes 266 defined in inner walls of the recesses 
264 and opening at side surfaces of the adapter blocks 238a, 238b. When 
setscrews 268 are threaded into the respective threaded holes 266, their 
tip ends are held against outer wall surfaces of the respective first and 
second knuckles 240, 242, holding the first and second knuckles 240, 242 
at angles which have been established desirably with respect to the 
adapter blocks 238a, 238b. 
The first knuckle 240 has a pair of substantially parallel spaced grippers 
270 such that the first knuckle 240 has a substantially channel-shaped 
cross section. The first knuckle 240 also has a threaded hole 272 defined 
in a bottom thereof for threaded insertion of the bolt 258 therein. The 
second knuckle 242 has an attachment tongue 274 for being inserted between 
the grippers 270, and a threaded hole 272 defined in a bottom thereof for 
threaded insertion of the bolt 258 therein. The grippers 270 have the 
through holes 244 defined respectively therein, and the attachment tongue 
274 has the through hole 246 defined therein. The shaft 248 extends 
through these through holes 244, 246 and also through the washers 250a, 
250b. 
The first knuckle 240 and the second knuckle 242 are coupled to each other 
for angular movement about the shaft 248. The first knuckle 240 and the 
second knuckle 242 are also mounted on the respective adapter blocks 238a, 
238b for angular movement about the bolts 258, and can be fixed at a 
desired angle with respect to the respective adapter blocks 238a, 238b by 
the setscrews 268. 
The structural members 20, 20a and the adapter blocks 238a, 238b should 
preferably be made of aluminum or aluminum alloy for smaller weight and 
higher rigidity. The first and second knuckles 240, 242 should preferably 
be made of aluminum alloy, stainless steel, carbon steel, molybdenum 
steel, or the like, and manufactured by precision casting, precision 
(cold) forging, lost-wax process, metal powder injection sintering, or the 
like. The first and second knuckles 240, 242 thus produced have a high 
strength, require no substantial subsequent machining, and are light in 
weight and low in cost. 
The joint mechanism according to this embodiment operates as follows and 
offers the following advantages: 
The surface of the adapter block 238b remote from the second knuckle 242 is 
positioned and against the end of the structural member 20. The ridges 262 
of the adapter block 238b are guided along the flat bottoms 27 of the 
slots 22, and fitted into the cavities 28 thereof. 
With the structural member 20 and the adapter block 238b being thus held 
against each other, the long screws 254 are threaded through the 
attachment holes 256a.about.256d of the adapter block 238b to fasten the 
structural member 20 and the adapter block 238b to each other. The joined 
surfaces of the structural member 20 and the adapter block 238b lie flush 
with each other (see FIG. 8). Specifically, the long screws 254 extend 
through the respective attachment holes 256a.about.256d of the adapter 
block 238b and are threaded into the second passages 32a.about.32d in the 
structural member 20. 
Similarly, the surface of the adapter block 238a remote from the first 
knuckle 240 is positioned and against the end of the other structural 
member 20a, and the long screws 254 are threaded through the attachment 
holes 256a.about.256d defined in the adapter block 238a near its four 
corners to fasten the structural member 20a and the adapter block 238a to 
each other. The order in which the adapter blocks 238a, 238b are attached 
to the structural members 20, 20a is arbitrary, and either one of the 
adapter blocks 238a, 238b may be attached first to the corresponding one 
of the structural members 20, 20a. 
As shown in FIG. 8, the structural members 20, 20a thus joined to each 
other can be angularly moved in the directions indicated by the arrows X 
or Y relatively to each other about the shaft 248 by which the first and 
second knuckles 240, 242 are coupled. The angles at which the first and 
second knuckles 240, 242 and the adapter blocks 238a, 238b are attached to 
each other may be varied using the setscrews 268 on the side surfaces of 
the adapter blocks 238a, 238b. Accordingly, it is possible to join the 
structural members 20, 20a to each other while they are being twisted a 
given angle in the directions indicated by the arrow Z. 
A joint mechanism according to still another embodiment of the present 
invention is shown in FIGS. 12 through 15. 
The joint mechanism according to this embodiment differs from the joint 
mechanism according to the preceding embodiment in that it joins 
confronting side surfaces of structural members to each other. The joint 
mechanism according to this embodiment can join the structural members 20, 
20a even when they extend parallel to each other. 
Specifically, a pair of adapter blocks 280a, 280b is different in shape 
from the adapter blocks according to the preceding embodiment. The adapter 
blocks 280a, 280b have recesses 284 in upper and lower surfaces thereof 
for installing respective hooks 282a, 282b therein (see FIG. 13). The 
hooks 282a, 282b have substantially T-shaped tip ends which are inserted 
and held in the corresponding slots 22 of the structural members 20, 20a. 
The hooks 282a, 282b are fixed to the upper and lower surfaces of the 
adapter blocks 280a, 280b by screws 286. As shown in FIG. 15, when the 
hook 282a (282b) is to be securely placed in the recess 284 in the adapter 
block 280a, a tapered surface 285 of the hook 282a (282b) is held against 
a tapered surface 287 of the recess 284. The hook 282a is then pressed 
downwardly when the screw 286 is threaded and tightened. As a result, the 
hook 282a (282b) is displaced in the direction indicated by the arrow C 
along the slanting tapered surface 287, and fixedly held in the recess 284 
(see FIG. 15). 
As shown in FIG. 13, the adapter blocks 280a, 280b also have respective 
substantially circular recesses 288 for receiving the bottoms of the first 
and second knuckle members 240, 242. The first and second knuckle members 
240, 242 are fastened to the respective adapter blocks 280a, 280b by the 
bolts 258. The joint mechanism according to the present embodiment is the 
same as the joint mechanism according to the preceding embodiment in that 
the first and second knuckle members 240, 242 are angularly movable in the 
recesses 288 in the directions indicated by the arrow Z about the bolts 
258, can be retained in a desired angle with respect to the adapter blocks 
280a, 280b by setscrews 290, and can be angularly moved in the direction 
indicated by the arrow X or Y relatively to each other about the shaft 248 
by which the first and second knuckles 240, 242 are coupled (see FIG. 12). 
For mounting the adapter blocks 280, 280a on the respective structural 
members 20, 20a, the tip ends of the hooks 282a on the upper and lower 
surfaces of the adapter blocks 280, 280a are inserted from ends of the 
structural members 20, 20a into the structural members 20, 20a along the 
slots 22. Then, the screws 286 are tightened to secure the hooks 282a, 
282b in the adapter blocks 280a, 280b and fix the adapter blocks 280a, 
280b to the structural members 20, 20a with the hooks 282a, 282b that are 
retained in the slots 22. 
Alternatively, it may be possible to detach the hooks 282a, 282b in advance 
from the adapter blocks 280a, 280b, insert the tip ends of the hooks 282a, 
282b longitudinally into the slots 22, thereafter turn the hooks 282a, 
282b about 90.degree. until the tip ends of the hooks 282a, 282b extend 
perpendicularly to the longitudinal axis of the slots 22, and couple the 
hooks 282a, 282b in the slots 22 to the adapter blocks 280a, 280b with the 
screws 286. 
Therefore, the structural members 20, 20a can be fixed to each other at a 
desired angle with the joint mechanism according to this embodiment. The 
joint mechanism according to this embodiment may be connected to angularly 
movable members such as door hinges, for example. FIG. 7 shows a 
preferable example in which structural members may be joined by joint 
mechanisms according to this embodiment. 
A joint mechanism according to yet still another embodiment of the present 
invention is illustrated in FIGS. 16 through 25. For using the joint 
mechanism according to this embodiment, the structural members 20, 20a 
have substantially circular recesses 334, 334a defined in mutually close 
regions thereof near their confronting ends for receiving first and second 
engaging members 330, 332, respectively, shown in FIGS. 17 and 18. 
As shown in FIG. 17, the joint mechanism for joining the structural members 
20, 20a comprises a first engaging member 330 having a disk 342 of 
substantially circular cross section and a pair of substantially 
triangular fingers 344 integrally formed with and angularly spaced 
180.degree. from each other on an outer circumferential surface of the 
disk 342, and a second engaging member 332 having a disk-shaped head 346 
and a bar 348 of prismatic shape integrally formed with the head 346. 
The first engaging member 330 has a hole 350 of regular hexagonal shape 
defined substantially centrally in an upper surface thereof, and a 
substantially circular hole 352 defined in a lower surface thereof 
eccentrically with respect to, i.e., out of coaxial alignment with, the 
hole 350. Since the circular hole 352 is off-center, the thickness of a 
wall extending around the circular hole 352 progressively varies from a 
smaller wall thickness to a greater wall thickness. The end of the bar 348 
of the second engaging member 332 which is remote from the head 346 has a 
hook 354 that has a curved surface held snugly against a curved inner wall 
surface of the hole 352. The structural members 20, 20a should preferably 
be made of a metallic material, and the first and second engaging members 
330, 332 should preferably be made of aluminum alloy, stainless steel, 
carbon steel, molybdenum steel, or the like, and manufactured by precision 
casting, precision (cold) forging, lost-wax process, metal powder 
injection sintering, or the like. The first and second engaging members 
330, 332 thus produced have a high strength, require no substantial 
subsequent machining, and are light in weight and low in cost. 
The joint mechanism according to this embodiment operates as follows and 
offers the following advantages: 
First, the second engaging member 332 is inserted into the structural 
member 20a along one of the slots 22 therein. The head 346 of the second 
engaging member 332 is fitted into the substantially circular hole 334a, 
and lies flush with the structural member 20a, whereupon the second 
engaging member 332 is retained in the slot 22 in the structural member 
20a. Specifically, the lower surface of the second engaging member 332 
abuts against the bottom surface 27 of the slot 22, and the upper surface 
of the second engaging member 332 lies flush with the upper surface of the 
structural member 20a. Accordingly, the second engaging member 332 is 
mounted in the slot 22 without projecting out of the structural member 
20a. Since the second engaging member 332 does not present an obstacle 
when the structural members 20, 20a are assembled together, it allows a 
space around the structural members 20, 20a to be utilized effectively. 
Then, the end of the other structural member 20 is brought closely to the 
end of the structural member 20a substantially in line therewith. With the 
hook 354 of the second engaging member 332 being held in engagement with 
the inner wall surface of the substantially circular hole 352 in the first 
engaging member 330, the first engaging member 330 is inserted into the 
substantially circular recess 334 that communicates with one of the slots 
22 in the structural member 20, until the first engaging member 330 in the 
substantially circular recess 334 lies flush with the structural member 
20. At this time, the inner wall surface of the recess 352 in the lower 
surface of the first engaging member 330 is held in engagement with the 
curved surface of the hook 354 on the end of the second engaging member 
332, and the fingers 344 on the outer circumferential surface of the disk 
342 of the first engaging member 330 are inserted in the slot 22 along its 
longitudinal axis. 
After the first engaging member 330 is inserted into the recess 334, the 
tip end of a tool such as a hexagonal wrench is fitted into the hole 350 
in the first engaging member 330, and turned in the direction indicated by 
the arrow in FIG. 19. When the first engaging member 330 is angularly 
moved until the fingers 344 abut against wall surfaces of the enlarged 
portion 26 of the slot 22 around the recess 334, the thickness of the wall 
of the first engaging member 330 which engages the curved surface of the 
hook 354 changes from the smaller wall thickness to the greater wall 
thickness. Therefore, the first engaging member 330 applies forces tending 
to pull the second engaging member 332 in the direction indicated by the 
arrow X in FIG. 20, displacing the second engaging member 332 in the 
direction indicated by the arrow X. The fingers 344 can easily be turned 
because the disk 342 of the first engaging member 330 is retained in the 
substantially circular recess 334 in the structural member 20. 
At the time the fingers 344 of the first engaging member 330 are held 
against the wall surfaces of the enlarged portion 26 of the slot 22, the 
first engaging member 330 is securely retained in the slot 22 in the 
structural member 20. 
As a consequence, the first engaging member 330 and the second engaging 
member 332 engage each other, firming joining the structural members 20, 
20a to each other. Joint mechanisms according to this embodiment may be 
mounted on two opposite side surfaces, respectively, of the structural 
members 20, 20a as shown in FIG. 20. Alternatively, joint mechanisms 
according to this embodiment may be mounted on three or four side 
surfaces, respectively, of the structural members 20, 20a for more 
securely joining the structural members 20, 20a for greater rigidity. 
Since the joint mechanism joins the structural members 20, 20a using at 
least one of the slots 22 defined in the respective four side surfaces of 
each of the structural members 20, 20a, the first and second engaging 
members 330, 332 may be mounted on a desired selected one of the four side 
surfaces of each of the structural members 20, 20a. Consequently, even if 
certain side surfaces of the structural members 20, 20a are not available 
because of limitations imposed by the conditions in which they are 
installed, the joint mechanism may be mounted on other available unlimited 
side surfaces of the structural members 20, 20a for thereby joining the 
structural members 20, 20a to each other. 
FIG. 21 shows in perspective the structural members 20, 20a joined to each 
other by the joint mechanism, with various pipe joints 356, 358, 360, 362, 
364 connected thereto in communication with the first passages 30 and the 
second passages 32a-32d. In order to connect the L-shaped pipe joint 362 
and the pipe joint 362, holes (not shown) having respective diameters 
corresponding to those of the pipe joints 360, 362 are defined in the 
bottom 27 of the corresponding slot 22. To connect the pipe joint 364, a 
hole is defined in a side surface of the structural member 20a. 
FIG. 22 shows in perspective the joined structural members 20, 20a shown in 
FIG. 21, with an insert 366 interposed between the structural members 20, 
20a. As shown in FIG. 23, the insert 366 comprises a substantially 
H-shaped block 368 having a first through hole 370 defined substantially 
centrally therein in communication with the first passage 30 in each of 
the structural members 20, 20a and supporting tubes 372a.about.372d 
projecting from a surface thereof near respective four corners thereof in 
communication with the second passages 32a.about.32d in each of the 
structural members 20, 20a. The tubes 372a.about.372d have respective 
through passages extending from one surface to the other of the block 368, 
and also project from the opposite surface thereof. The insert 366 has a 
pair of substantially rectangular recesses 374 defined in respective 
opposite side surfaces thereof for receiving the bar 348 of the second 
engaging member 332. 
The insert 366 also has a second through hole 376 defined therein which 
extends perpendicularly to the axis of the first through hole 370 in 
communication therewith, the second through hole 376 opening at opposite 
side surfaces of the insert 366. The second through hole 376 includes a 
reduced-diameter through hole 376a (see FIGS. 24 and 25) extending from a 
region where the second through hole 376 communicates with the first 
through hole 370. The second through hole 376 is internally threaded at an 
inlet end thereof, so that a pipe joint, for example, can easily be 
connected to the second through hole 376 by being threaded into the 
internally threaded inlet end of the second through hole 376. Seals 378, 
379 are mounted in annular grooves defined around the first through hole 
370 and the tubes 372a.about.372d for allowing the first through hole 370 
and the tubes 372a.about.372d to be hermetically connected to the 
structural members 20, 20a. 
For coupling the insert 366 between the structural members 20, 20a, the 
insert 366 is placed between the confronting ends of the structural 
members 20, 20a, and the tubes 372a.about.372d projecting toward the ends 
of the structural members 20, 20a are fitted into the second passages 
32a.about.32d in the structural members 20, 20a, before the first and 
second engaging members 330, 332 are installed. As a result, the first 
passages 30 in the structural members 20, 20a communicate with each other 
through the first through hole 370, and communication passages defined in 
the structural members 20, 20a along the axes thereof communicate with the 
second through hole 376, 376a perpendicular to the first through hole 370. 
The first engaging member 330 and the second engaging member 332 are 
installed in the same manner as described above, and hence the process of 
installing the first engaging member 330 and the second engaging member 
332 will not be described in detail below. 
A joint mechanism for joining structural members according to a further 
embodiment of the present invention is shown in FIGS. 26 through 31. 
The joint mechanism according to this embodiment is different from the 
joint mechanism according to the preceding embodiment in that a second 
engaging member 380 has a substantially T-shaped head 382 (see FIGS. 26 
and 27), and the joint mechanism is used to join the structural members 
20, 20a substantially perpendicularly to each other (see FIG. 28). The 
joint mechanism has a first engaging member 330 which is of a structure 
that is substantially identical to the first engaging member 330 according 
to the preceding embodiment. 
For joining the structural members 20, 20a to each other, the head 382 of 
the second engaging member 380 is inserted from an end of the structural 
member 20a into one of the slots 22 therein. Alternatively, after the head 
382 is inserted longitudinally into the slot 22, the head 382 may be 
turned about 90.degree. so as to be mounted in the slot 22. Then, the 
first engaging member 330 is inserted into the slot 22 such that the inner 
wall surface of the substantially circular hole 352 in the first engaging 
member 330 engages the curved surface of the hook 354 on an end of the 
second engaging member 380. At this time, the first engaging member 330 is 
retained in the substantially circular recess 334 in the slot 22, and the 
first engaging member 330 is inserted so as to align the fingers 344 with 
the slot 22, as indicated by the solid lines in FIG. 28. Since the 
circular hole 352 is off-center, the thickness of the wall extending 
around the circular hole 352 progressively varies from the smaller wall 
thickness to the greater wall thickness. When the first engaging member 
330 is then angularly moved a predetermined angle, the fingers 344 of the 
first engaging member 330 are angularly displaced the predetermined angle 
as indicated by the broken lines in FIG. 28. As a result, as shown in FIG. 
30, the thicker wall portion of the first engaging member 330 abuts 
against the curved surface of the hook 354 of the second engaging member 
380, pulling the second engaging member 380 in the direction indicated by 
the arrow X. Therefore, the structural member 20a is pulled in the 
direction indicated by the arrow X, and joined and fixed perpendicularly 
to the other structural member 20. As shown in FIG. 31, joint mechanisms 
according to the present embodiment may be mounted respectively on upper 
and lower surfaces of the structural member 20 to firmly join the 
structural members 20, 20a with increased rigidity. 
FIGS. 32 through 35 show a joint mechanism for joining structural members 
according to a yet still further embodiment of the present invention. The 
joint mechanism according to this embodiment is used to join the 
structural members 20, 20a substantially perpendicularly to each other. 
As shown in FIG. 32, the joint mechanism comprises first and second 
engaging members 384, 386, and a screw 388 having a tapered tip end 387 
which is progressively smaller in diameter. The first engaging member 384 
has a pair of fingers 392 disposed on an outer circumferential surface of 
a cylinder 390 and angularly spaced 180.degree. from each other. The first 
engaging member 384 also has an internally threaded through hole 394 
defined centrally therein. The second engaging member 386 has a 
substantially T-shaped head 396 and a flat plate 398 joined to the head 
396 and having a tapered recess 400 remote from the head 396. 
For joining the structural members 20, 20a to each other, the head 396 of 
the second engaging member 386 is inserted from an end of the structural 
member 20a into one of the slots 22 therein. Alternatively, after the head 
396 is inserted longitudinally into the slot 22, the head 396 may be 
turned about 90.degree. so as to be mounted in the slot 22. Then, the 
other structural member 20 is placed substantially perpendicularly to the 
structural member 20a, and the flat plate 398 of the second engaging 
member 286 which projects from the structural member 20a is inserted into 
the slot 22 in the other structural member 20. 
The first engaging member 384 is inserted into the substantially circular 
recess 334 in the slot 22 in the structural member 20. Since the diameter 
of the substantially circular recess 334 is substantially the same as the 
diameter of the cylinder 390, the first engaging member 384 is retained in 
the recess 334. At this time, the first engaging member 384 is inserted so 
as to align the fingers 392 with the slot 22. 
Then, the screw 388 is threaded into the internally threaded through hole 
394 that is defined substantially centrally in the first engaging member 
384. As the screw 388 is threaded in, the first engaging member 384 is 
angularly moved in the direction indicated by the arrow in FIG. 33, 
bringing the fingers 392 into abutment against the wall surfaces of the 
enlarged portion 26 of the slot 26, whereupon the first engaging member 
384 is retained in the slot 22, as indicated by the broken lines in FIG. 
33. When the screw 388 is further threaded in, the tapered tip end 387 of 
the screw 388 engages in the tapered recess 400 in the flat plate 398 (see 
FIG. 34), pressing a slanting surface of the tapered recess 400. As a 
result, the second engaging member 386 is displaced in the direction 
indicated by the arrow X by the pressing action of the tapered tip end 
387. The structural member 20a is pulled in the direction indicated by the 
arrow X, and joined and fixed perpendicularly to the other structural 
member 20. As shown in FIG. 35, joint mechanisms according to the present 
embodiment may be mounted respectively on upper and lower surfaces of the 
structural member 20 to firmly join the structural members 20, 20a with 
increased rigidity. 
FIGS. 36 through 39 show a joint mechanism for joining structural members 
according to another embodiment of the present invention. As with the two 
previous embodiments, the joint mechanism according to this embodiment is 
used to join the structural members 20, 20a substantially perpendicularly 
to each other. 
The joint mechanism has a pair of engaging members 408a, 408b each having a 
substantially T-shaped head 402 and a tapered member 406 including an 
internally threaded through hole 404 and a tapered surface 405 which is 
progressively smaller in diameter. The joint mechanism also has a 
substantially cylindrical sleeve 410 interposed between the engaging 
members 408a, 408b. The sleeve 410 has a pair of opposite tapered surfaces 
412 each inclined at a slightly smaller angle than the tapered surface 
405, and a through hole 414 defined therein between the opposite tapered 
surfaces 412. A bolt 416 extends through the through holes 404 in the 
engaging members 408a, 408b and the hole 414 in the sleeve 410. The hole 
414 in the sleeve 410 has a diameter greater than the diameter of the bolt 
416. 
For joining the structural members 20, 20a to each other, the heads 402 of 
the engaging members 408a, 408b are inserted from an end of the structural 
member 20a into one of the slots 22 therein. Then, the other structural 
member 20 is placed substantially perpendicularly to the structural member 
20a, and the tapered members 406 of the engaging members 408a, 408b are 
inserted respectively into the substantially circular recesses 334 in the 
slots 22 defined respectively in the upper and lower surfaces of the 
structural member 20. The sleeve 410 is fitted in a through hole that is 
defined transversely in the structural member 20 between the slots 22, the 
through hole having a diameter corresponding to the diameter of the sleeve 
410. 
Then, the bolt 416 is inserted into the tapered members 406 of the engaging 
members 408a, 408b and the sleeve 410 (see FIG. 38). When the bolt 416 is 
threaded in, the tapered surfaces 405 of the engaging members 408a, 408b 
are drawn into the sleeve 410 along the tapered surfaces 412 thereof. As a 
consequence, the heads 402 of the engaging members 408a, 408b exert forces 
tending to pull the structural member 20a in the direction indicated by 
the arrow X, joining and fixing the structural member 20a to the other 
structural member 20 (see FIG. 39). 
FIG. 40 shows the structural member 20 with a cover 23 of substantially 
channel-shaped cross section being mounted in one of the slots 22 which is 
used as a wiring passage for a lead 418. 
A pair of locking members 420a, 420b for locking the lead 418 is mounted in 
the slot 22 in the structural member 20, and a connector 422 with a 
plurality of terminals is connected to an end of the lead 418. 
The joint mechanisms according to the present invention offer the following 
advantages: 
The passage communication member is used simply to keep the passage in one 
of the structural members in communication with the passage in the other 
structural member. 
With the passages in the structural members being held in communication 
with each other by the passage communication member, the first engaging 
member inserted in the recess in one of the structural members and the 
second engaging member retained in the slot in the other structural member 
are coupled to each other by the fastening member. Therefore, the 
structural members can easily be joined and fixed to each other. 
Consequently, the period of time that is required to join the structural 
members is greatly reduced, and the efficiency with which the structural 
members are joined is increased. 
Because the passage communication member and the first and second engaging 
members are simple in structure, they can be manufactured inexpensively on 
a mass-production basis. 
Furthermore, one of the joint mechanisms according to the present invention 
allows the structural members to be joined to each other for angular 
movement about the shaft. It is possible to join and fix the structural 
members to each other as they have been angularly moved a desired angle 
about the shaft. 
The first and second knuckles and the blocks can be attached to each other 
at a given angle established by the angle setting means. Therefore, the 
structural members can be joined and fixed to the each other as they have 
been twisted relatively to each other. 
The joint mechanism may be connected to angularly movable members such as 
door hinges, for example, and the angularly movable members may be 
angularly displaced about the shaft. 
According to the present invention, furthermore, the structural members can 
easily be joined to each other in line with or perpendicularly to each 
other by the first engaging member and the second engaging member which 
are of simple structure. The labor that is needed to join the structural 
members to each other can be reduced, the period of time that is required 
to joint the structural members to each other can be shortened, so that 
the efficiency of assembling the structural members can be increased. 
INDUSTRIAL APPLICABILITY 
The joint mechanisms for joining structural members according to the 
present invention may be used in a wide range of applications, e.g., to 
join structural members that are used in fluid pressure circuits and 
machines, components, apparatus, etc. which employ fluid pressure.