U.S. patent application number 12/695679 was filed with the patent office on 2010-09-09 for work carrier.
This patent application is currently assigned to DAIHEN CORPORATION. Invention is credited to Kunio FUKUMA, Hideki MATSUO.
Application Number | 20100224343 12/695679 |
Document ID | / |
Family ID | 42677193 |
Filed Date | 2010-09-09 |
United States Patent
Application |
20100224343 |
Kind Code |
A1 |
FUKUMA; Kunio ; et
al. |
September 9, 2010 |
WORK CARRIER
Abstract
A work carrier includes a work carrying mechanism, a cooling
pipe for cooling the work carrying mechanism by circulation of a
coolant, a thermally-conductive elastic member held in contact with
the work carrying mechanism and the cooling pipe, and a fixing
element for fixing the cooling pipe to the work carrying mechanism.
The elastic member is made of aluminum, for example. Before fixed,
the elastic member is bent in a cross section perpendicular to the
longitudinal direction of the cooling pipe.
Inventors: |
FUKUMA; Kunio; (Osaka,
JP) ; MATSUO; Hideki; (Osaka, JP) |
Correspondence
Address: |
HAMRE, SCHUMANN, MUELLER & LARSON, P.C.
P.O. BOX 2902
MINNEAPOLIS
MN
55402-0902
US
|
Assignee: |
DAIHEN CORPORATION
Osaka
JP
|
Family ID: |
42677193 |
Appl. No.: |
12/695679 |
Filed: |
January 28, 2010 |
Current U.S.
Class: |
165/67 |
Current CPC
Class: |
B65G 49/067 20130101;
B25J 19/0054 20130101; B65G 2249/02 20130101; H01L 21/67742
20130101; H01L 21/67109 20130101; B65G 49/061 20130101 |
Class at
Publication: |
165/67 |
International
Class: |
F28F 9/013 20060101
F28F009/013 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 29, 2009 |
JP |
2009-017824 |
Claims
1. A work carrier comprising: a work carrying mechanism; a cooling
pipe for cooling the work carrying mechanism by circulation of a
coolant; a thermally-conductive elastic member held in contact with
the work carrying mechanism and the cooling pipe; and a fixing
element for fixing the cooling pipe to the work carrying
mechanism.
2. The work carrier according to claim 1, wherein the elastic
member extends in a longitudinal direction of the cooling pipe.
3. The work carrier according to claim 1, wherein the elastic
member is bent in a cross section perpendicular to a longitudinal
direction of the cooling pipe prior to fixation.
4. The work carrier according to claim 1, wherein the elastic
member is made of a deformable metal.
5. The work carrier according to claim 4, wherein the elastic
member is made of aluminum.
6. The work carrier according to claim 1, wherein the cooling pipe
includes a flat surface held in contact with the elastic
member.
7. The work carrier according to claim 1, further comprising: a
scissors lift mechanism for vertically lifting and lowering the
work carrying mechanism; a base seat on which the scissors lift
mechanism is mounted; and a rotation mechanism for rotating the
base seat about a vertical axis.
8. The work carrier according to claim 7, wherein: the scissors
lift mechanism comprises: a stage on which the work carrying
mechanism is mounted; a first scissors link including a first arm
and a second arm; a second scissors link arranged parallel to the
first scissors link and including a third arm and a fourth arm; and
a lifting driver mounted on the base seat; the first arm and the
second arm are connected to each other at central portions of the
respective arms so as to be rotatable to each other; the first arm
includes an upper end portion rotatably connected to the stage, and
a lower end portion horizontally movable near the base seat; the
second arm includes a lower end portion rotatably connected to the
base seat, and an upper end portion horizontally movable near the
stage; the third arm and the fourth arm are connected to each other
at central portions of the respective arms so as to be rotatable to
each other; the third arm includes an upper end portion rotatably
connected to the stage, and a lower end portion horizontally
movable near the base seat; the fourth arm includes a lower end
portion rotatably connected to the stage, and an upper end portion
horizontally movable near the stage; and the lifting driver is
configured to move the lower end portions of the first arm and the
third arm near the base seat.
9. The work carrier according to claim 8, further comprising: a
lower pipe extending from the lower end portion of the second arm
to the central portion of the second arm; an upper pipe extending
from the upper end portion of the third arm to the central portion
of the third arm; and an intermediate pipe extending between the
central portion of the second arm and the central portion of the
third arm and connected to the lower pipe and the upper pipe.
10. The work carrier according to claim 9, further comprising: a
through pipe extending from the base seat, via the lower end
portion of the second arm and connected to the lower pipe; and a
connection pipe connecting between the upper pipe and the work
carrying mechanism.
11. The work carrier according to claim 10, wherein the through
pipe, the lower pipe, the intermediate pipe, the upper pipe and the
connection pipe are configured to provide a pipeline in which a
coolant supply pipe and a coolant discharge pipe, both connected to
the cooling pipe, are accommodated.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a work carrier that carries
a plate-shaped work, for example in a vacuum space.
[0003] 2. Description of the Related Art
[0004] An example of carrying apparatuses that carry a plate-shaped
work in a vacuum space so far developed is disclosed in JP-A-No.
2007-118171. The work carrier according to this document includes a
fixed base, a pivotal base retained by the fixed base pivotally
with respect thereto, a lift base to which the pivotal base is
mounted, a ball screw slide mechanism that vertically moves the
lifting base, a link arm mechanism supported by the pivotal base to
be swingable with respect thereto, and a hand supported by the link
arm mechanism.
[0005] The hand and the link arm mechanism are located in the
vacuum space, while the fixed base is located in the atmospheric
space. The upper wall of a casing of the fixed base separates the
upper vacuum space from the lower atmospheric space. The fixed base
contains therein motors for rotating the pivotal base and for
driving the link arm mechanism, the ball screw slide mechanism, and
a motor for driving the ball screw slide mechanism.
[0006] In the work carrier thus constructed, a work, which is
heated to a high-temperature, may affect the peripheral components
by radiant heat. In light of this, the link arm mechanism, which is
most likely to be exposed to the radiant heat, is provided with a
coolant circuit for cooling the peripheral components, that is
arranged to extend from inside the fixed base and through the
pivotal base. In the vicinity of a guide rail of the link arm
mechanism, an annular pipe is provided in communication with the
coolant circuit.
[0007] In the foregoing conventional work carrier, however, the
coolant circulating pipe has a circular cross section, and hence
the contact area of the pipe with respect to the frame member of
the link arm mechanism tends to be unduly small. Unfavorably, such
a structure may impede efficient heat dissipation from the frame
member exposed to the radiant heat.
SUMMARY OF THE INVENTION
[0008] The present invention has been proposed under the foregoing
situation. It is therefore an object of the present invention to
provide a work carrier configured to efficiently dissipate heat
from a member liable to be exposed to radiant heat.
[0009] To attain the foregoing object, the present invention adopts
the following technical measures.
[0010] According to an embodiment of the present invention, there
is provided a work carrier comprising: a work carrying mechanism; a
cooling pipe for cooling the work carrying mechanism by circulation
of a coolant; a thermally-conductive elastic member held in contact
with the work carrying mechanism and the cooling pipe; and a fixing
element for fixing the cooling pipe to the work carrying
mechanism.
[0011] Preferably, the elastic member extends in a longitudinal
direction of the cooling pipe.
[0012] Preferably, the elastic member is bent in a cross section
perpendicular to a longitudinal direction of the cooling pipe prior
to fixation.
[0013] Preferably, the elastic member is made of a deformable
metal.
[0014] Preferably, the elastic member is made of aluminum.
[0015] Preferably, the cooling pipe includes a flat surface held in
contact with the elastic member.
[0016] Preferably, the work carrier of the present invention
further comprises: a scissors lift mechanism for vertically lifting
and lowering the work carrying mechanism; a base seat on which the
scissors lift mechanism is mounted; and a rotation mechanism for
rotating the base seat about a vertical axis.
[0017] Preferably, the scissors lift mechanism comprises: a stage
on which the work carrying mechanism is mounted; a first scissors
link including a first arm and a second arm; a second scissors link
arranged parallel to the first scissors link and including a third
arm and a fourth arm; and a lifting driver mounted on the base
seat. The first arm and the second arm are connected to each other
at central portions of the respective arms so as to be rotatable to
each other. The first arm includes an upper end portion rotatably
connected to the stage, and a lower end portion horizontally
movable near the base seat. The second arm includes a lower end
portion rotatably connected to the base seat, and an upper end
portion horizontally movable near the stage. The third arm and the
fourth arm are connected to each other at central portions of the
respective arms so as to be rotatable to each other. The third arm
includes an upper end portion rotatably connected to the stage, and
a lower end portion horizontally movable near the base seat. The
fourth arm includes a lower end portion rotatably connected to the
stage, and an upper end portion horizontally movable near the
stage. The lifting driver is configured to move the lower end
portions of the first arm and the third arm near the base seat.
[0018] Preferably, the work carrier of the present invention
further comprises: a lower pipe extending from the lower end
portion of the second arm to the central portion of the second arm;
an upper pipe extending from the upper end portion of the third arm
to the central portion of the third arm; and an intermediate pipe
extending between the central portion of the second arm and the
central portion of the third arm and connected to the lower pipe
and the upper pipe.
[0019] Preferably, the work carrier of the present invention
further comprises: a through pipe extending from the base seat, via
the lower end portion of the second arm and connected to the lower
pipe; and a connection pipe connecting between the upper pipe and
the work carrying mechanism.
[0020] Preferably, the through pipe, the lower pipe, the
intermediate pipe, the upper pipe and the connection pipe are
configured to provide a pipeline in which a coolant supply pipe and
a coolant discharge pipe, both connected to the cooling pipe, are
accommodated.
[0021] In accordance with the above arrangement, the work carrying
mechanism, liable to be exposed to radiant heat, is provided with a
cooling pipe which is pressure fixed to the work carrying
mechanism, with an elastic member disposed between the pipe and the
work carrying mechanism. In this manner, the cooling pipe is held
in contact with the work carrying mechanism via the elastic member.
Thus, the cooling pipe is to have an advantageously large contact
area and therefore capable of effectively drawing heat from the
elements of the work carrying mechanism exposed to radiant
heat.
[0022] Other features and advantages of the present invention will
become more apparent from the detailed description given below with
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is an exploded perspective view showing a work
carrier according to an embodiment of the present invention;
[0024] FIG. 2 is a side view showing main portions of the work
carrier shown in FIG. 1;
[0025] FIG. 3 is a front view showing main portions of the work
carrier shown in FIG. 1;
[0026] FIG. 4 is a perspective view showing a work carrying
mechanism provided in the work carrier shown in FIG. 1;
[0027] FIG. 5 is a partially cut away plan view of the work
carrying mechanism shown in FIG. 4; and
[0028] FIGS. 6A and 6B are cross-sectional views showing the fixing
structure of a cooling pipe provided in the work carrying mechanism
shown in FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Preferred embodiments of the present invention will be
described below with reference to the accompanying drawings.
[0030] FIGS. 1 to 6B depict a work carrier according to an
embodiment of the present invention. The work carrier A is intended
for carrying a thin plate-shaped work such as an LCD panel. The
work carrier A includes a base unit 1 that accommodates a rotation
mechanism (not shown), a base seat 2, a scissors lift mechanism 4,
an upper pipe 5, an intermediate pipe 6, a lower pipe 7, and a work
carrying mechanism 8. The base unit 1 is located in the atmospheric
space below the floor level, while the base seat 2, the scissors
lift mechanism 4, the upper pipe 5, the intermediate pipe 6, the
lower pipe 7, and the work carrying mechanism 8 are located, for
example, in a vacuum space inside a non-illustrated chamber. By the
work carrier A, a work heated for example up to approximately
200.degree. C. is carried in the vacuum space. For better
understanding, FIG. 1 illustrates the scissors lift mechanism 4 and
the work carrying mechanism 8 in a separated state. The inside of
the chamber does not have to be a completely vacuum space, but may
be a space depressurized to a certain extent, or pressurized to a
certain extent. The inside of the chamber may be loaded with a
substance other than air (for instance, nitrogen).
[0031] The base unit 1 accommodates therein a rotation mechanism
that rotates the base seat 2 about a vertical axis. The rotation
mechanism is constituted of a planet gear mechanism, including e.g.
a driving motor for attaining required rotational movement. The
rotation mechanism includes a rotating shaft 10 of a hollow
structure, connected to a lower face of the base seat 2 via a
sealed bearing 11 (See FIG. 1). The rotation of the rotating shaft
10 causes the base seat 2 to rotate about the vertical axis. The
inside of the base unit 1 is maintained at the atmospheric
pressure. The base unit 1 accommodates only the rotation mechanism
for rotating the base seat 2 about the vertical axis, but not the
motors for rotating a pivotal base or for driving a link arm
mechanism, a ball screw slide mechanism, and a motor for driving
the ball screw slide mechanism. Accordingly, the overall structure,
in particular the height, can be more compact than is
conventionally possible. Since the base unit 1 can be significantly
smaller in height than a conventional one, the base unit 1 can be
accommodated in an advantageously shallow underfloor space.
[0032] The base seat 2 serves to sustain the scissors lift
mechanism 4. On the upper face of the base seat 2, a through pipe 3
is provided. An end portion of the through pipe 3 is led into the
base unit 1 through the hollow portion of the rotating shaft 10.
The other end portion of the through pipe 3 is connected to the
lower pipe 7 through a lower relay pipe 30 (See FIG. 2). Other
constituents provided on the base seat 2 will be described
later.
[0033] The scissors lift mechanism 4 serves to sustain the work
carrying mechanism 8, and to vertically reciprocate the work
carrying mechanism 8 as a whole. The scissors lift mechanism 4
includes a stage 40 on which the work carrying mechanism 8 is
mounted, a first and a second scissors link 41, 42, and a lift
driving motor 43. The first scissors link 41 includes a first and a
second arms 410, 411, and the second scissors link 42 also includes
a third and a fourth arms 420, 421 of the same shape and size as
those of the first and second arms. The first and the second
scissors link 41, 42 are disposed parallel to each other on the
respective sides of the stage 40, with a spacing therebetween.
[0034] On a rear end portion of the upper face of the base seat 2,
a pair of brackets 21 and a pair of bearings (not shown) are
provided so as to connect a respective lower end portion of the
arms 411, 421 rotatably about a horizontal axis. Between the two
brackets 21, an air-tightly sealed motor box 22 that accommodates
therein the lift driving motor 43 is provided. On a front end
portion of the upper face of the base seat 2, a pair of ball screw
shafts 23, and a nut block 24, as well as a pair of slide rails 25
and a pair of linear blocks 26 are provided so as to connect a
respective lower end portion of the arms 410, 420 horizontally
slidably back and forth. The ball screw shaft 23 is made to rotate
by the lift driving motor 43, so that the nut block 24
thread-engaged with the ball screw shaft 23 is made to slide back
and forth. To the end portions of the nut block 24, the lower end
portion of the arms 410, 420 are rotatably connected respectively.
The respective lower end portions of the arms 410, 420 are
supported by the slide rail 25 via the linear block 26.
[0035] As shown in FIG. 3, the through pipe 3 is once introduced
into the air-tightly sealed motor box 22, and communicatively
connected to the lower relay pipe 30 sticking outward from inside
the motor box 22. A swivel joint J1 is provided so as to penetrate
through the lower end portion of the arm 411 and the bracket 21,
and the lower relay pipe 30 is communicatively connected to the
lower end portion of the lower pipe 7 via the swivel joint J1.
Here, FIG. 3 is a front view of the scissors lift mechanism 4 from
a position slightly ahead of the intermediate pipe 6, and hence the
arms 410, 411, 420, 421 are partially cut away.
[0036] The upper pipe 5 is disposed from an upper end portion to a
central portion of the arm 420, along an outer face of the arm 420.
The intermediate pipe 6 is located so as to connect the central
portion of the arms 410, 411 and that of the arms 420, 421. The
lower pipe 7 is disposed, as shown in FIG. 3, from the central
portion to the lower end portion of the arm 411, along an outer
face of the arm 411. An L-shaped joint J2 is disposed so as to
penetrate through the middle portion where the arms 410, 411
intersect with each other, and the upper end portion of the lower
pipe 7 is communicatively connected to an end portion of the
intermediate pipe 6 via the L-shaped joint J2. The other end
portion of the intermediate pipe 6 is communicatively connected to
the lower end portion of the upper pipe 5, via a swivel joint J3
disposed so as to penetrate through the central portion where the
arms 420, 421 intersect with each other.
[0037] On the upper face of the stage 40, the work carrying
mechanism 8 is fixed. On a rear end portion of the lower face of
the stage 40, a pair of brackets 40A and a pair of bearings (not
shown) are provided so as to connect the respective upper end
portion of the arms 410, 420, rotatably about a horizontal axis. On
a front end portion of the lower face of the stage 40, a pair of
slide rails 40B and a pair of linear guides 40C are provided so as
to connect the respective upper end portion of the arms 411, 421,
horizontally slidably back and forth. On a region from the rear end
portion to a central portion of the lower face of the stage 40,
connection pipes 40E, 40F, 40G and a through connection pipe 40H
are provided. An end portion of the connection pipe 40E is
communicatively connected to the upper end portion of the upper
pipe 5 via a swivel joint J4 disposed so as to penetrate through
the upper end portion of the arm 420 and the bracket 40A. The other
end portion of the connection pipe 40E is communicatively connected
to an end portion of the connection pipe 40F via an L-shaped joint
J5 disposed so as to penetrate through the upper end portion of the
arm 410 and the bracket 40A. The other end portion of the
connection pipe 40F is communicatively connected to an end portion
of the connection pipe 40G via an L-shaped joint J6. The other end
portion of the connection pipe 40G is communicatively connected via
an L-shaped joint J7 to a lower end portion of the through
connection pipe 40H disposed so as to penetrate through the central
portion of the stage 40. An upper end portion of the through
connection pipe 40H is connected to the work carrying mechanism
8.
[0038] Thus, the through pipe 3, the lower relay pipe 30, the upper
pipe 5, the intermediate pipe 6, the lower pipe 7, the connection
pipes 40E, 40F, 40G, and the through connection pipe 40H constitute
a pipeline that achieves communication from the inside of the base
unit 1 to the work carrying mechanism 8. The pipeline is
air-tightly sealed to be thereby maintained at the atmospheric
pressure. The pipeline thus arranged accommodates power supply
cables for the slide-driving motor of the work carrying mechanism 8
and for the lift driving motor 43, while also accommodating the
coolant supply pipe and the coolant discharge pipe that serve to
cool the components of the work carrying mechanism 8. Such
configuration enables routing the power supply cables, the coolant
supply pipe and the coolant discharge pipe from the inside of the
base unit 1 to the motor box 22 and the work carrying mechanism 8,
without exposing them to the vacuum space. In this embodiment, a
liquid such as water is employed as the coolant from the viewpoint
of thermal efficiency. Alternatively, for example dry air may be
employed as the coolant.
[0039] The work carrying mechanism 8 includes a pair of hands 80
that retains the work, a belt sliding mechanism 81 (See FIGS. 4 and
5) serving to linearly reciprocate the hands 80 horizontally back
and forth independently from each other, a sealed box 82 that
accommodates therein a slide-driving motor that activates the belt
sliding mechanism 81, a guide member 83 that retains the belt
sliding mechanism 81 and the sealed box 82, and a cooling pipe 84
for coolant circulation.
[0040] As shown in FIG. 1, the guide member 83 includes a main body
83A and a cover 83B, and has a rectangular shape in plan view. As
shown in FIG. 4, the main body 83A includes a first and a second
guide rail 83C, 83D each constituted of a set of two rows,
extending longitudinally. The first guide rail 83C movably sustains
a lower end portion 80a of the upper one of the hands 80 via a
slider 80b, and the second guide rail 83D movably sustains a lower
end portion of the other hand 80 via a slider 80c, so as not to
interfere with the upper hand 80. The first and the second guide
rails 83C, 83D are covered with the cover 83B, which includes slits
80d, 80e formed at a position corresponding to each guide rail 83C,
83D, for sticking out the sliders 80b, 80c (See FIG. 1). A lower
end portion 80a of the upper hand 80 is formed so as to circumvent
an outer edge of the lower hand 80, so that the two hands 80 are
located so as to vertically overlap defining a gap therebetween,
and can therefore horizontally move back and forth without mutual
interference.
[0041] Referring to FIGS. 4 and 5, the belt sliding mechanism 81 is
constituted of a pair, so as to extend longitudinally. The pair of
belt sliding mechanisms 81 each includes an inner and outer pair of
belts 81A, 81B looped about a pulley which is not shown. To the two
rows of belts 81A, 81B on the right, for example, the lower end
portion 80a of the upper hand 80 is connected via the slider 80b
(See FIG. 4). When the belts 81A, 81B on the right rotate, the
upper hand 80 is made to horizontally move back and forth along the
guide rail 83C. To the two rows of belts 81A, 81B on the left, the
lower end portion of the lower hand 80 is connected via the slider
80c (See FIG. 4). When the belts 81A, 81B on the left rotate, the
lower hand 80 is made to horizontally move back and forth along the
guide rail 83D. Instead of two rows, a single row of belt may be
provided on the left and the right respectively.
[0042] As shown in FIG. 5, the sealed box 82 is located at a
generally central portion of the main body 83A. The sealed box 82
accommodates therein the slide-driving motors 82C, 82D and
reduction gears 82E, 82F, serving to rotate the belts 81A, 81B. On
each lateral face of the sealed box 82, driving gears 82G, 82H and
tension rollers 82J that drive the belts 81A, 81B are attached, and
the belts 81A, 81B are engaged about the driving gears 82G, 82H and
the tension rollers 82J. The two driving gears 82G, 82H on one of
the lateral faces of the box body 82A, for example, is supported
via a sealed bearing (not shown) by a drive shaft (not shown) of
the reduction gear 82E sticking out from the lateral face of the
box body 82A, and the rotating speed and direction of the driving
gears 82G, 82H are switched through controlling the slide-driving
motor 82C. The two driving gears 82G, 82H located on the other side
of the box body 82A are also configured as above. Thus, the two
sets of belts 81A, 81B on the respective sides are independently
rotated, so that the upper and the lower hands 80 are made to slide
independent from each other.
[0043] The sealed box 82 includes a communication orifice (not
shown) formed through the bottom portion thereof, for introducing
the coolant supply pipe and the coolant discharge pipe into the
sealed box 82. To the communication orifice, the through connection
pipe 40H on the stage 40 is air-tightly connected. Through the
through connection pipe 40H and the communication orifice thus
configured, the coolant supply pipe and the coolant discharge pipe,
and also the power supply cable are introduced into the sealed box
82. Inside the sealed box 82, the leading end portion of the
coolant supply pipe is connected to an upstream branch socket 82K,
and the leading end portion of the coolant discharge pipe is
connected to a downstream branch socket 82L. To the upstream branch
socket 82K, two sets of cooling pipes 84 are connected, so as to be
led out through the air-tight through hole from inside the sealed
box 82. These cooling pipes 84 pass around the periphery of the
belt sliding mechanism 81 and return to the inside of the sealed
box 82, to be connected to the downstream branch socket 82L. The
cooling pipes 84 are located so as to surround the belt sliding
mechanism 81 and the guide rails 83C, 83D. In other words, the
cooling pipes 84 are provided such that the coolant flowing therein
circulates about the belt sliding mechanism 81 and the guide rails
83C, 83D. Accordingly, the belt sliding mechanism 81 and the guide
rails 83C, 83D, closely exposed to the radiant heat, exhibit
efficient heat dissipation performance because of the coolant
flowing through inside the cooling pipes 84.
[0044] As shown in FIG. 6A, the cooling pipe 84 is constituted of,
for example, a pipe made of stainless steel and having a
rectangular cross section. The frame member 830 constituting the
main body 83A is of stainless steel for example. A bracket 86 and
bolts 87, serving as fixing elements, are used to fix the cooling
pipe 84 under pressure to the frame member 830, with the elastic
member 85 interposed between the pipe 84 and the frame member 830.
FIGS. 4 and 5 show a plurality of brackets, only some of which are
indicated by numeral 86, with the remaining ones unnumbered.
[0045] The elastic member 85 is a metal strip in the form of a leaf
spring and made of a heat-conducting material such as gold, silver,
copper or aluminum. A elastic member 85 made of aluminum may be
advantageous in terms of cost reduction. In a natural state, i.e.
before the cooling pipe 84 is fixed, the elastic member 85 is
slightly bent as viewed in a cross section perpendicular to the
longitudinal direction of the cooling pipe 84. Then, with the
elastic member 85 held between the frame member 830 and the cooling
pipe 84, the bracket 86 is attached to the frame member 830 so that
the cooling pipe 84 is fixed to the frame member 830 under the
urging force of the bracket 86, and the elastic member 85 is
deformed between the frame member 830 and the cooling pipe 84. As
the elastic member 85 is being pressed further between the frame
member 830 and the cooling pipe 84, the elastic member 85 is so
deformed that the contact area with respect to the frame member 830
and the cooling pipe 84 increases. It should be noted here that
though the contact surface of the elastic member 85 thus fixed is
depicted as being flat in FIG. 6B, the contacting surface may be
actually slightly bent.
[0046] It is possible to enjoy some cooling effect by contacting
the flat surface of the cooling pipe 84 with the frame member 830
directly. However, the elastic member 85, disposed between the
cooling pipe 84 and the frame member 830 ensures more proper
contact between them, thereby enhancing the cooling effect. In
addition, the elastic member 85 compensates thermal distortion of
the cooling pipe 84 by absorbing or following the deformation,
thereby preventing degradation of the cooling effect. The elastic
member 85 may be made of a relatively hard material such as
stainless steel, but preferably made of aluminum, which is soft
enough to deform in accordance with the profile of the frame member
830 and the cooling pipe 84, thereby ensuring proper contact
between the frame member 830 and the cooling pipe 84 for efficient
thermal conduction. In this manner, the elastic member 85 prevents
partial contact or even point contact between the frame member and
the cooling pipe.
[0047] If the elastic member 85 is not used, and the cooling pipe
84 is pressed directly onto the frame member 830 by the bracket 86,
the contact area between the frame member 830 and the cooling pipe
84 may be unduly small, so that the cooling effect by the cooling
pipe 84 may be insufficient.
[0048] In the above-described embodiment of the present invention,
on the other hand, the elastic member 85 can deform properly
between the frame member 830 and the cooling pipe 84, so as to
increase its contact area with respect to the cooling pipe 84 as it
is being pressed. As a result, a larger contact area can be
expected between the frame member 830 and the cooling pipe 84 than
when no such member like the elastic member 85 is employed.
[0049] Further, by fixing the cooling pipe 84 under pressure with
the elastic member 85 intervening, it is possible to ensure proper
contact between the frame member 830 and the elastic member 85. In
such an instance, the elastic member 85 is deformed between the
frame member 830 and the cooling pipe 84, whereby the frame member
830 and the elastic member 85 are properly contacted with each
other, and the contact area between the frame member 830 and the
elastic member 85 increases as the pressing proceeds.
[0050] While the elastic member 85 is being pressed further, the
contact area between the elastic member 85 and the cooling pipe 84
and the contact area between the frame member 830 and the elastic
member 85 will increase to an extent which is not attainable when
no deformation occurs and a mere contact is expected. Thus, the
cooling effect by the cooling pipe 84 can be enhanced due to the
enlarged contact area, in comparison with the case in which the
elastic member 85 is not used.
[0051] As seen from the above, the elastic member 85 is made of a
metal which is deformable under pressure and preferably a good heat
conductor. More specifically, the elastic member 85 is preferably
less hard than the frame member 830 and the cooling pipe 84, so
that it can properly deform when press fixed. Thus, when the
cooling pipe 84 and the frame member 830 are made of stainless
steel, the elastic member 85 is made of a softer metal, for
example, aluminum. The initial shape of the elastic member 85 is
not limited to that shown in FIG. 6A, and may be corrugated as
viewed in its cross section. Alternatively, the elastic member 85
may be made of an expanded metal.
[0052] With the above-described arrangement of the elastic member
85, heat is efficiently conducted from the frame member 830,
through the elastic member 85 and the walls of the cooling pipe 84,
and finally to the coolant flowing in the cooling pipe 84.
Accordingly, heat present at the frame member 830 can be quickly
drawn and dissipated by the coolant.
[0053] As shown in FIG. 5, use may be made of a plurality of
brackets 86 at predetermined positions along the longitudinal
direction of the cooling pipe 84 for pressure fixing the cooling
pipe 84 to the frame member 830. The intervals between adjacent
brackets may be determined suitably for each application. The
elastic member 85 may be formed so as to extend longitudinally of
the cooling pipe 84, to have generally the same length as the
cooling pipe 84 or a shorter length than the pipe. When the elastic
member 85 is shorter than the pipe, a plurality of elastic member
85 may preferably be used so that the overall contact area can be
as great as possible. In such an instance, the lengths and
positions of the elastic members 85 and brackets 86 with respect to
the cooling pipe 84 may be determined by considering the cooling
effect in the actual situation.
[0054] The workings of the work carrier A will be described
below.
[0055] To deliver a work in the vacuum space, the work carrying
mechanism 8 retains the work and moves it horizontally, and the
scissors lift mechanism 4 is driven so as to vertically lift or
lower the work carrying mechanism 8 as a whole. The rotation
mechanism installed in the base unit 1 rotates the scissors lift
mechanism 4 and the work carrying mechanism 8 together. With such
an arrangement, the work can be carried in the three-dimensional
space, from a predetermined initial position to a desired target
position.
[0056] As shown in FIG. 2, when the scissors lift mechanism 4 is to
be activated, the ball screw shaft 23 is rotated so that the nut
block 24 is made to horizontally slide back and forth along the
ball screw shaft 23. Since the end portions of the nut block 24 are
connected to the lower end portions of the first and third arms
410, 420, respectively, the lower end portions of the arms 410, 420
are caused to slide along the slide rail 25.
[0057] As the lower end portions of the arms 410, 420 are caused to
slide, the lower end portions of the second and fourth arms 411,
421 and the upper end portions of the first and third arms 410, 420
are caused to rotate about the brackets 21, 40A, and the upper end
portions of the second and fourth arms 411, 421 are slave-driven to
slide along the slide rail 40B. With such an arrangement, the stage
40 is vertically lifted or lowered while keeping the horizontal
posture.
[0058] When the stage 40 is vertically lowered, for example to a
position indicated by imaginary lines in FIG. 2 by the movement of
the scissors lift mechanism 4, the work carrying mechanism 8 as a
whole, unillustrated but mounted on the stage 40, is also lowered
to the minimal height with reference to the base seat 2, whereby
the hands 80 can be brought to the lowest possible level.
[0059] It should be noted that even when the stage 40 is brought to
the lowest level by the scissors lift mechanism 4, there may be
some vertical gap between the base seat 2 and the stage 40, due to
the structural characteristics of the scissors lift mechanism 4. In
light of this, the motor box 22 may preferably be disposed in the
gap, so that it is possible not only to attain the vertical
downsizing of the scissors lift mechanism 4, but also to
effectively utilize the space above the base seat 2.
[0060] The height of the motor box 22 depends on e.g. the size of
the lift driving motor 43, and hence it may not always be possible
to properly accommodate the motor box 22 within the gap formed when
the stage 40 is brought to the lowest position. For instance, when
the stage 40 is lowered to the lowest position by the scissors lift
mechanism 4, the motor box 22 would interfere with the stage 40 or
the connection pipes 40E, 40G. This problem may be overcome by
limiting the vertical movement range of the scissors lift mechanism
4 so that the motor box 22 is well spaced from the stage 40 or the
connection pipes 40E, 40G. In this case, it is preferable to
provide an additional mechanism for ensuring contact prevention.
With these arrangements, the stage 40 may only be lowered to a
level slightly higher than the lowest position that would otherwise
be reached. However, the difference in height may be very small,
the advantage of the downsizing in the vertical direction can still
be enjoyed.
[0061] Another solution differing from the above is to locate the
motor box 22 at a position where no interference with the stage 40
or the connection pipes 40E, 40G will occur. To this end, if
necessary, the surface area of the base seat 2 may be increased. In
this case, a gear box may be used between the lift driving motor 43
and the ball screw shaft 23, thereby increasing the degree of
freedom in positioning the motor box 22.
[0062] When the the scissors lift mechanism 4 operates, the
positional relations between the upper pipe 5, the intermediate
pipe 6, the lower pipe 7, and the connection pipe 40E attached to
the arms 410, 411, 420, 421 may change. The upper pipe 5, the
intermediate pipe 6, the lower pipe 7, and the connection pipe 40E
are communicatively connected rotatably to each other via the
air-tightly sealed swivel joints J1, J3, J4 and the L-shaped joint
J2. Thus, the internal coolant supply pipe and coolant discharge
pipe are not adversely affected. Further, during the operation of
the rotation mechanism, it is possible to prevent the coolant
supply pipe and the coolant discharge pipe from being tangled or
unduly twisted, whereby the proper routing condition of these pipes
can be maintained along the arms 410, 411, 420, 421.
[0063] The work carrying mechanism 8 is most susceptible to thermal
influence by radiant heat from the work heated. In this connection,
since the belt sliding mechanism 81 and the guide rails 83C, 83D
are required to maintain high dimensional precision for carrying
the work, they have to be sufficiently isolated from the thermal
influence. In the embodiment of the present invention, the cooling
pipe 84 is disposed so as to surround the belt sliding mechanism 81
and the guide rails 83C, 83D. Thus, the coolant circulating through
the cooling pipe 84 can efficiently cool the belt sliding mechanism
81 and the guide rails 830, 83D.
[0064] Specifically, the radiant heat from the work is transmitted
to the frame member 830 via the hand 80. The frame member 830 is
held in contact with the cooling pipe 84 over its entire length via
elastic members 85 in the form of leaf springs. Thus, the heat from
the frame member 830 is quickly transmitted to the coolant flowing
inside the cooling pipe 84, via the elastic members 85 and the
cooling pipe 84. Consequently, the thermal effect on the belt
sliding mechanism 81 and the guide rails 83C, 83D can be mitigated,
so that the work can be carried with high accuracy by the work
carrying mechanism 8 that can be effectively cooled.
[0065] In accordance with the work carrier A of the above
embodiment, the cooling pipe 84 is provided on the frame member 830
located close to the belt sliding mechanism 81 and the guide rails
83C, 83D, hence prone to suffer the radiant heat, where the cooling
pipe 84 as a whole is brought into contact with the frame member
via the elastic members 85. Such a structure provides a large
contact area between the cooling pipe 84 and the frame member,
thereby facilitating efficient heat dissipation from the frame
member 830 and hence effectively suppressing thermal deformation of
the belt sliding mechanism 81 or the guide rails 83C, 83D.
Consequently the belt sliding mechanism 81 and the guide rails 83C,
83D, which play an important role in performing accurate work
carrying, can be stabilized against heat so that the work can be
carried with high accuracy.
[0066] The work carrier A described above includes the work
carrying mechanism 8, the scissors lift mechanism 4, and the
rotation mechanism, among which only the rotation mechanism needs
to be located under the base seat 2. Thus, the height of the lower
unit 1 accommodating therein the rotation mechanism can be reduced.
Accordingly, the overall size of the work carrier A can be easily
reduced by suppressing the height of the base seat 2, and further
the size of the manufacturing equipment, in particular the height
thereof, can be reduced. Such a compact lower unit 1 can be
installed in an underfloor space that is advantageously
shallow.
[0067] The coolant supply pipe and the coolant discharge pipe are
laid in the pipeline extending from the base unit 1 to the work
carrying mechanism 8. Thus, the routing condition of these pipes
can be made stable, without disturbing the operation of the
scissors lift mechanism 4 and the rotation mechanism.
[0068] Also, by vertically lowering the work carrying mechanism 8
with the use of the scissors lift mechanism 4, the height of the
hands 80 with reference to the base seat 2 can be as small as
possible.
[0069] The present invention is not limited to the above-described
embodiments.
[0070] In the above embodiment, the elements J1, J3, J4 are swivel
joints and the elements J2, J5 are non-rotating L-shaped joints.
Differing from this, the elements J1, J2, J5 may be swivel joints
and the elements J3, J4 may be L-shaped joints. In any case, swivel
joints may be used to allow the rotation of the intermediate pipe 6
and the connection pipe 40E when the scissors lift mechanism 4
operates. If all the elements J2 to J5 were L-shaped joints, the
intermediate pipe 6 and the connection pipe 40E would be
non-rotatably connected at their ends, and hence the scissors lift
mechanism 4 would not be operable. In light of this, in the
above-described scissors lift mechanism 4, swivel joints are used
for the element J1 and the element disposed at one end of each of
the intermediate pipe 6 and of the connection pipe 40E, so that the
scissors lift mechanism 4 can perform lifting or lowering movement
without being subject to any restriction. In this connection, all
the elements J1 to J5 may be swivel joints, but the cost can be
reduced by using an L-shaped joint for some of the elements J1 to
J5, as noted above.
[0071] The cooling pipe may be formed so as to have a semicircular
cross section, instead of the rectangular one as in the foregoing
embodiment. In this case, the flat surface of the cooling pipe is
disposed so as to face the frame member, and the cooling pipe is
pressure fixed to the frame member by a bracket, with an elastic
member disposed between the cooling pipe and the frame member. In
any case, the cooling pipe may need to have a flat contact surface
to be brought into contact with an elastic member. This contact
surface may cause no problem even if it is slightly bent or warped,
but may preferably be as flat as possible for enabling better
thermal conduction. In a case where the cooling pipe is formed to
have a semicircular cross-section, the bracket is also made into a
form corresponding to the shape of the cooling pipe. When the
cooling pipe to be in contact with the elastic member has a flat
surface, preferably the frame member may also have a flat surface
facing the elastic member.
* * * * *