TECHNICAL FIELD OF THE INVENTION
[001] The present invention relates to the field of low-voltage switchgear
and control-gear assemblies, particularly with regard frame structure of an
enclosure having improved degree of protection against solid objects and water
5 (IP code).
BACKGROUND OF THE INVENTION
[002] An enclosure for low-voltage switchgear and control-gear assemblies
is usually a steel frame structure covered with doors and covers. They are
used to build low-voltage switchgear and control-gear assemblies by installing
10 electrical equipment ( circuit breakers, fuses, contactors, relays, etc.) and
connecting by conductors (busbars, wires, and cables). Electrical enclosure
manufacturers are trying to improve their products in many ways. Improvement
of degree of protection (IP code) is one such aspect.
[003] Degrees of protection (IP code) of enclosures are defined in IEC 60529.
15 The degree of protection (IP code) is indicated by two characteristic numerals.
The first characteristic numeral (numerals Oto 6, or letter X) indicates protection
against access to hazardous parts and against solid foreign objects. The second
characteristic numeral (numerals O to 9, or letter X) indicates protection against
ingress of water. The higher numeral characteristic indicates the higher level
20 of protection. Where the characteristic numeral indicates no protection, it
shall be replaced by the letter "X". For example, IP54, where "5'' indicates
protection against dust and "4" indicates protection against splashing water. The
easiest method of increasing the IP code of an enclosure is welding. But yielding
method has disadvantages such as limited number of configurations (lack of
25 modularity), lack of extension of enclosure whenever required, increased space
during storage and transportation.
[004] The invention is an improved modular frame structure of an enclosure for
low-voltage switchgear and control-gear assemblies. The frame structure of this
electrical enclosure differs from the prior art. It includes a set of components
30 namely corner block, corner bar, corner bar extension block, cross bar, and cross
bar extension block. All these components have improved features which enable
them to build an enclosure with improved degree of protection (IP code).
[005] Core components, i.e. Corner Block, Corner Bar, Corner Bar Extension
Block, Cross Bar and Cross Bar Extension Block have been improved in the
3
invention. As described in the detailed description the new corner block with a
gasket is an improvement of the corner block disclosed in International
Application Number PCT/DK93/00401 (WO 94/14307). The invention disclosed in
PCT/DK93/00401 can be considered as the closest prior art and is referred to as
5 Dl in this section. In the closest prior art DI, there are three tapped holes on
projections on the corner blocks and another tapped hole on an outer face of
the corner block. Each of the four holes meets at an inside center point of the
corner block. Since the four holes meet at one point, the water entering from
the outer tapped hole runs through all three other holes and reaches inside the
10 electrical enclosure. The assembling mechanism of the corner bar has been
improved by removing corner bar anchor (as defined in D1) and the fixing holes
corresponding to corner bar anchor. Apart from that all other components of the
invention, i.e. corner bar extension block, cross bar and cross bar extension block
are equipped with improved assembling mechanisms to improve the degree of
15 ingress protection.

We Claim:
1. A modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly, the modular frame structure being
built up by a plurality of corner blocks, corner bars, corner bar extension
5 blocks, cross bars, and cross bar extension blocks assembled together and
comprising:
a solid cubical corner block comprising:
three square-shaped orthogonal projections (12), with tapered
top edges (20), on three of its base faces, each of which having
10 a height of h1 mm from base face to top surface of the
projection (12), a tapped center hole (16) having a diameter
of d1 mm at the center of the top surface of the projection
(12) and a thread height of h2 mm running from center of the
top surface of the projection (12) towards the center of the
15 corner block (10) where h2 mm thread height is less than the
height of h3 mm from top surface of the projection (12) to the
center of the corner block (10) and the depth of the center
hole (16) is greater than h1 mm, where the depth of the
center hole (16) always stops at distance less than h3 -
20 0.5d1 mm from the top surface of the projection (12)
and lies in the range of h1 < h2 < h3-0.5d1 mm while
keeping a gap of g1 mm between end of the center hole (16)
and the closest border of the auxiliary hole (17), avoiding the
center hole (16) sinking into auxiliary hole (17) and three flat
25 faces without any projections on them;
an auxiliary hole (17) closed with a set screw (18), having the
d1 mm diameter and the h2 mm thread height located at the
center of one flat face (14) and aligned to center hole (16) in
the projection (12) on the corresponding base face (13) of the
30 corner block (10) where the width of a base face (13) or flat
face (14) of the corner block (10) is h4 mm and the h2 mm
thread height of it runs deeper in the corner block (10) than that
of center hole (16), whereby the h1 mm height of projection
(12) is further determined in a manner where the h2 mm
35 thread height of auxiliary hole (17) and the h2 mm thread
20
height of center hole (16), both aligned, do not meet each
other inside the corner block (10), creating a gap of g2 mm
between the end points of the both depths of two holes (16
and 17) where the g2 mm gap having adequate material
5 strength to withstand against torque of two screws driven in
the center hole (16) and auxiliary hole (17) avoid creating
any passage between each other or any disturbance to each
other;
a base face (13) having a continuous groove (21) at the bottom
10 of the projection (12) and on the two external edges of the
base face (13), where the depth of the groove (21) is deep
enough to hold a gasket; and
a square-shaped gasket (22) with rounded corners placed
around the projection (12) and inserted in the groove (21),
15 having an internal width slightly greater than the width of the
top surface of the projection (12) and a height of the gasket
(22) not even on all four sides of which two sides of the gasket
(22) which come on to the groove (21) on external edges of
the corner block (10) are bulged and the height of two
20 adjoining bulged sides (23) of the gasket (22) is greater than
that of the other two sides of the gasket (22) and is slightly
greater than the depth of the groove (21);
a corner bar having a square-shaped profile with rounded corners
and internal longitudinal surfaces with series of tapped holes (33a)
25 and free holes (33b) located one after the other, comprising:
an internal width of such profile being slightly greater than the
width of the front surface of the projection (12) of the corner
block (10), not exceeding the h4 mm width of the base face or
flat face of the corner block (10); and
30 two corner bar anchors (34) each comprising a partially squareshaped steel block (36) with a substantial thickness, a hole
(41) and two tapped holes (42) on the thickness; a bolt (37);
and an O-ring (38), whereby the two corner bar anchors (34)
placed at the two ends of the corner bar (30) in a slot (35)
21
located after the first hole from each end of the corner bar
(30);
a cross bar having a rectangular-shaped profile with rounded
corners and internal longitudinal surfaces with series of tapped
5 holes (66a) and free holes (66b) located one after the other,
comprising at each end:
a cylindrical anchor (68) having two free holes (68a and 68b)
on its body, installed inside at each end of the cross bar (65) by
reverting one end of the cylindrical anchor (68);
10 an assembling device (70) comprising a guide pin (73) with a
base plate (71), a bolt (72), a conical spring (74) and a retainer
washer (75) whereby the bolt (72) is inserted through the hole
(71a) on the base plate (71), the conical spring (74) and the
hole (68a) on the cylindrical anchor (68) and is retained on the
15 cylindrical anchor (68) by a retainer washer (75) attached to
the thread end of the bolt (72) while the guide pin (73) is
inserted through the hole (68b) on the cylindrical anchor (68);
and
a cross bar insert (67) having a free holes (67b) located at the
20 center and another free hole (67a) in the middle between the
free hole (67b) and an end of the cross bar insert (67),
corresponding to the free holes(68b and 68a) on the cylindrical
anchor (68);
a corner bar extension block (50) for joining plurality of corner
25 bars(30) and cross bars (65) comprising:
two square-shaped projections (51) on its top and bottom
base faces (56a) to assemble corner bars and two rectangularshaped projections (52) on two adjoining side base faces (56b)
to assemble cross bars, of which the edges (51a and 52a) of the
30 front surface of the square-shaped projections (51) and the
rectangular-shaped projections (52) are slightly tapered and
having rounded corners;
a center hole (53) at the center of the front surface of each top
22
and bottom projections (51) of which the width of the front
surface is equal to the width of the front surface of the
projection (12) on the corner block (10);
two tapped holes (58) and a free hole (59) located in line with
5 an equal distance to the free hole (59) at the center on the
front surface of the rectangular-shaped projection (52);
a continuous groove (54) located at the bottom of each
projection (51) on the two external edges of the top and the
bottom square-shaped base faces (56a);
10 a continuous groove (60) located at the bottom of each
projections (52) on three external edges of the rectangular
base face (56b);
a square-shaped gasket (22) with rounded corners placed
around the projection (51) and inserted in the groove (54)
15 where the internal width of the gasket (22) is slightly greater
than the width of the top surface of the projection (51) and
the height of the gasket (22) is not even on all four sides of
which two sides of the gasket (22) which come on to the
groove (54) on external edges of the square-shaped base faces
20 (56a) are bulged and the height of two adjoining bulged sides
(23) of the gasket (22) is greater than that of the other two
sides of the gasket (22) and isslightly greater than the depth of
the groove (54) enabling the two sides without bulges rest on
the top or bottom square-shaped base face (56a); and
25 a rectangular-shaped gasket (61) with rounded corners placed
around the projection (52) and inserted in the groove (60)
where the internal width of the gasket (61) is slightly greater
than the width of the top surface of the projection (52) and
the height of the gasket (61) not even on all four sides of
30 which three sides of the gasket (61) which come on to the
groove (60) on the three external edges of the rectangular
base face (56b) are bulged and the height of three adjoining
bulged sides (62) of the gasket (61) is greater than that of the
other side of the gasket (61) and is slightly greater than the
23
depth of the groove (60) enabling the side without a
bulge rests on rectangular-shaped base face (56b); and
a cross bar extension block (80) for joining plurality of cross bars
(65) comprising:
5 two rectangular shaped-side projections (81) having slightly
tapered top edges (81a) and rounded corners, on the left side
(80a) and right side (80b) base faces (82);
two tapped holes (81b) and a free hole (81c) located in line
with an equal distance to the free hole (81c) at the center on
10 the front surface of the two projections (81) where each
tapped hole (81b) is placed in the middle point between the
free hole (81c) and the corresponding edge of the front surface
of the projections (81) and tapped holes (81b) on the two
front surfaces of the projections (81) are located in a diagonal
15 manner;
two tapped holes (90) and a free hole (91) located in line with
an equal distance to the free hole (91) at the center of the
flat surface (83a or 83c) where each tapped hole (90) is placed
in the middle point between the free hole (91) and the
20 corresponding edge of the flat surface (83a and 83c) and the
tapped holes (90) on the two flat surfaces (83a and 83c) are
located in a diagonal manner;
two free holes (87) and four tapped holes (88) arranged in
three horizontal rows to be able to select a matching
25 configuration of a free hole (87) and a tapped hole (88)
depending on the orientation of the guide pin (73) and the bolt
(72) of the assembling device (70) at each end of the cross bar
(65);
a continuous groove (85) located at the bottom of each
30 projection (81) on three external edges of the base face (82);
and
a rectangular-shaped gasket (61) with rounded corners placed
around the projection (81) and inserted in the groove (85), of
24
which the internal height and width (61) is slightly greater than
the height and the width of the top surface of the projection
(81) and the height of the gasket (61) is not even on all four
sides of which three sides which come on to the groove (85) on
5 edges of the rectangular-shaped base faces (82), are bulged
and the height of the three adjoining bulged sides (62) of the
gasket (61) is greater than that of the other side of the gasket
(61) and is slightly greater than the depth of the groove (85);
2. The modular frame structure adapted for enclosure of a low-voltage
10 switchgear and control-gear assembly of Claim 1, wherein each projection
(12) of the corner block (10) has rounded side edges (12a), rounded corners
(12b) on the top surface, tapered edges (12c) on the top surface and a center
hole (16) located at the center of the top surface.
3. The modular frame structure adapted for enclosure of a low-voltage
15 switchgear and control-gear assembly of Claim 1, wherein the height of the
projection (12) h1 mm, of the corner block (10), is determined to provide
adequate thread height h2 mm to the center hole (16), which is greater than
h1 mm, so that a screw driven into a depth in the center hole (16), is
adequate to firmly assemble a frame member with stability when assembling
20 to the corner block (10).
4. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 3, wherein the height
of the projection (12), of the on the corner block (10), is high enough to
insert it in full and retain inside the corner bar and the height of projection
25 (12) h1 mm is determined to limit the thread height of the center hole (16)
to h2 mm to allow the gap of g1 mm having adequate material strength to
withstand against torque of the screw driven in the center hole (16) avoiding
any disturbance auxiliary hole (17) or other two center holes (16) thereby the
length of the gap carries the property of g1 being greater than 1.5 mm
30 where g1 = h3-h2-0.5d1 mm.
5. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the thread height
of the auxiliary hole (17), of the corner block (10), is greater than h3-0.5d1
mm.
25
6. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the length of the
gap between the end points of the depths of the center hole (16) and the
auxiliary hole (17), of the corner block (10), carries the property of g2 being
5 greater than 1.5 mm where g2= h4+h 1-2h2 in millimeters.
7. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the arrangement
of three center holes (16) and auxiliary hole (17) in the corner block (10)
prevent none of the four holes reaching into any of the other holes (16 or 17)
10 or making any passage to enter any substance into the electrical enclosure.
8. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the opening (45) in
the corner bar is used to insert a screwdriver to fasten the corner bar anchor
(34).
15 9. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the shape of the
steel block (36) appears as if two smaller rectangular shaped portions (39)
have been removed from the two diagonal corners of a square shaped first
steel block (40) having a side length of x1 mm.
20 10. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 9, wherein the height
and width of the rectangular shaped portions (39) are determined in a
manner which creates adequate space to insert the corner bar anchor (34)
into the slot (35).
25 11. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 9, wherein the height
and width of the rectangular shaped portions (39) removed from the first
block (40) are minimized to the extent which the corner bar anchor (34) can
be inserted into the slot (35) and maximum length from the steel block (36)
30 entangles with the cross-section of the cross bar (30).
12. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim l and 9, "wherein the portion
of the steel block (36) which entangles with the cross-section of the cross bar
(30) moves the cross bar towards the corner block when assembling the
26
corner bar (30) to the corner block (10).
13. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 9, wherein the x1 mm
side length, of the steel block (36), is greater than the internal width of
5 square-shaped profile of the corner bar and is equal to the total of the
internal width of square-shaped profile of the corner bar and the thickness
of the corner bar which is x3 mm.
14. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 9, wherein the side
10 surface (44) of the resultant steel block (36) is kept evenly surfaced with the
two longitudinal internal surfaces (31) of the corner bar (30).
15. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 9, wherein the
resultant steel block (36) after removing the two portions (39) has two sides
15 of each having a width of x2 mm, which stay inside the corner bar (30) when
the steel block (36) is fully inserted into the slot (35) in the corner bar (30)
where the x2 mm width is always slightly less than the internal width of the
square-shaped profile of the corner bar (30), allowing the steel block (36) to
be inserted in to the slots (35) in the corner bar (30).
20 16. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 9, wherein the hole
(41) on the steel block (36), meant for the bolt (37), is off-set from the
center of the first steel block (40) and is positioned on the steel block (36)
centering to the center of the square-shaped profile of the corner bar (30),
25 coinciding with the center hole (16) on the front surface of the projection
(12) on the corner block (10),
17. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 9, wherein the bolt
(37) is retained in the steel block (36) by the O-ring (38).
30 18. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 9, wherein the two
tapped holes (42) are located on two sides of the steel block (36), visible
when it is inserted in the slot (35) on the two internal longitudinal surfaces
(31) of the corner bar (30) and are positioned in line with the series of holes
27
(33a and 33b) on the two internal longitudinal surfaces (31) of the corner
bar (30).
19. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the height of the
5 two square-shaped projections (51) on the top and bottom base faces (56a)
of the corner bar extension block (50) are higher than the two rectangularshaped projections (52) on two adjoining side base faces (56b) of the corner
bar extension block (50).
20. The modular frame structure adapted for enclosure of a low-voltage
10 switchgear and control-gear assembly of Claim 1, wherein each tapped hole
(58) on the front surface of the projection (52) is placed in the middle point
between the free hole (59) and the corresponding edge of the front surface
of the projection (52).
21. The modular frame structure adapted for enclosure of a low-voltage
15 switchgear and control-gear assembly of Claim 1, wherein the height and
the width of the projection (52) of the corner bar extension block (50) are
equal to the inner width and height of the cross- section of a cross bar (65).
22. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the reverted end
20 and the other end of the cylindrical anchor (68), of the cross bar (65),
provides two tapped holes (66a) on the respective internal longitudinal
surfaces to maintain the modularity on the series of holes (66a and 66b).
23. The modular frame structure adapted for enclosure of a !ow-voltage
switchgear and control-gear assembly of Claim 1, wherein the free hole
25 (68a) on the cylindrical anchor (68), passes through the center of the
cylindrical anchor (68) and the other free hole (68a) is placed in the middle
between the free hole (68b) and one end of the cylindrical anchor (68)
thereby the free hole (68a) is located diagonally at each end of the cross bar
(65).
30 24. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the two free holes
(67a and 67b) on the cross bar insert (67) are located coinciding to the two
free holes (68a and 68b) on the cylindrical anchor (68) respectively, thereby
the assembling device (70) at each end of the cross bar (65) is freely
28
movable through holes (68a and 68b) on the cylindrical anchor (68).
25. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein two bolts (72) in
the assembling devices (70), are located diagonally at each end of a cross bar
5 (65).
26. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the height and
the width of the front surface of the projection (81) on the cross bar
extension block, is equal to the internal height and the width of the cross10 section of the cross bar (65) enabling the projection (81) to be inserted into
an end of the cross bar (65).
27. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the two tapped
holes (88) and a free hole (87) are placed vertically in line with an equal
15 distance to the free hole (87) at the center of that line, of the internal flat
surface (86) of the cross bar extension block (80), where each tapped hole
(88) is placed in the middle point between the free hole (87) and the
corresponding edge of the internal flat surface (86) and each tapped hole
(88) is located diagonally to corresponding tapped hole (88).
20 28. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the distance
between a tapped hole (88) in top or bottom row and a corresponding free
hole (87) in the middle row of the cross bar extension block, is equal to the
distance between the free hole (68a) and the free hole (68b) on the
25 cylindrical anchor (68) at the end of a cross bar (65).
29. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claims 1 and 28, the bolt (72) and
the guide pin (73), of the assembling device (70) at each end of the cross bar
(65), are inserted in to the corresponding tapped hole (88) and free hole (87)
30 when assembling a cross bar (65) to the internal flat surface (86) of the cross
bar extension block (80) thereby two cross bars (65) can be assembled to the
internal flat surface (86) of the cross bar extension block (80).
30. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the linear
29
distance between a free hole (59, 81c or 87) and a respective adjoining
tapped hole (58, 81b or 88) on the corner bar extension block (50) or cross
bar extension block (80), is equal to the distance between the two free holes
(68a and 68b) on the cylindrical anchor (68) at the end of a cross bar (65) or
5 to the distance between the two free holes (67a and 67b) on the cross bar
insert (67).
31. The modular frame structure adapted for enclosure of a low-voltage
switchgear and control-gear assembly of Claim 1, wherein the two tapped
holes on either sides of a free hole on a particular surface of the corner bar
10 extension block (50) or cross bar extension block (80) allow to assemble a
cross bar (65) to a corner bar extension block (50) or cross bar extension
block (80) irrespective of the diagonal placement of the bolt (72) of the
assembling device (70) at each end of the cross bar (65).
32. A method for assembling the components to build a modular frame
15 structure according to Claim 1, comprising steps of:
assembling a corner bar (30) with a corner block (10):
preparation of corner bar anchors: one steel block (36) is
inserted to a slots (35) at one end of the corner bar (30)
and two bolts (37) are inserted, facing opposite directions,
20 from the other end of the corner bar (30); the second steel
block (36) is inserted to the other slots (35) at the other
end of the corner bar (30); each bolt (37) is passed
through hole (41); 0-ring (38) is attached to each bolt (37);
the tapered projection (12) on the corner block (10) is
25 inserted into one end of the corner bar (30) in itsfull height
and the bolt (37) is driven into center hole (16) on the
projection (12) on the corner block (10) by a screw driver
inserted through opening (45) on the corner bar (30), until
the gasket (22) is pressed into the groove (54) on the
30 square-shaped base face (56a);
assembling a cross bar (65) to a corner bar (30) or an
external/internal cross bar (65):
a cross bar insert (67) is placed in between the end of the
30
cross bar (65) and the corner bar (30) or the external cross
bar (65). When a cross bar (65) is assembled to other
frame members, i.e. a corner bar extension block (50),
cross bar extension block (80) or an internal cross bar (65),
5 the cross bar insert (67) is not used in between the cross
bar end and such frame member.
the bolt (72) in the assembling device (70) at the end of the
cross bar (65) is driven into the corresponding tapped hole
(33a or 66a) on the longitudinal surface of the corner bar
10 (30) or cross bar (65), while the guide pin (73) is inserted
in to another corresponding free hole (33b or 66b)
on the longitudinal surface of the corner bar (30) or cross
bar (65), by a screw driver inserted through opening (69)
on the crossbar (65) until the bolt (72) is fasten tightly.
15 Assembling a corner bar extension block (50) to a corner bar (30): one
of the tapered projections (51) is inserted into the end of the corner
bar (30) in its full height and then the bolt (37) in the corner bar
anchor (34) is driven into center hole (53) on the projection (51) on the
corner bar extension block (50) by a screw driver inserted through
20 opening (45) on the corner bar (30), until the gasket (22) is pressed into
the groove (54) on the square-shaped base face (56a). The other
projection (51) of the corner bar extension block (50) is inserted in to
one end of another corner bar (30) and assembled them in a similar
manner;
25 Assembling a corner bar extension block (50) to a cross bar (65): the
tapered rectangular projection (52) is inserted into the end of the
cross bar (65) in its full height; the bolt (72) in the assembling device
(70) at the end of the cross bar (65) is driven into either of the
corresponding the tapped hole (58) on the projection (52) while the
30 guide pin (73) is inserted in to the free hole (59) on the projection (52)
on the corner bar extension block (50), by a screw driver inserted
through opening (69) on the cross bar (65), until the gasket (61) is
pressed into the groove (60) on the rectangular-shaped base face
(56b);
35
31
Assembling a cross bar extension block (80) to a cross bar (65):
the tapered projections (81) of the cross bar extension block (80), is
inserted into the end of the cross bar (65) in its full height; the bolt (72)
in the assembling device (70) at the end of the cross bar (65) is driven
5 into the tapped hole (81b) on the projection (81) while the guide pin
(73) is inserted in to the free hole (81c) on the projection (81) on the
cross bar extension block (80), by a screw driver inserted through
opening (69) on the cross bar (65), until the gasket (61) is pressed into
the groove (85) on the rectangular-shaped base face (82);
10 Assembling a cross bar (65) to a cross bar extension block (80) using its
flat surfaces (83a and 83c): the bolt(72) in the assembling device (70) at
the end of the cross bar (65) is driven into either of the corresponding
tapped hole (90) while the guide pin (73) is inserted in to the free hole
(91) on the flat surface (83a or 83c) of the cross bar extension block
15 (80), by a screw driver inserted through opening (69) on the cross bar
(65), until the cross bar (65) becomes complete contact with the cross
bar extension block (80);
Assembling one or two cross bars to internal flat surface (86) of the cross
bar extension block (80): the bolt (72) in the assembling device (70) at the
20 end of the cross bar (65) is driven into a selected tapped hole (88) while
the guide pin (73) is inserted in to the selected free hole (87) on the
internal flat surface (86) of the cross bar extension block (80), by a screw
driver inserted through opening (69) on the cross bar (65), until the cross
bar (65) becomes complete contact with the flat surface (86) of the cross
25 bar extension block (80). Similarly, another cross bar (65) can be
assembled to the same flat surface (86) of the cross bar extension block
(80) according to the design requirement of the modular frame structure.