Apparatus for coating the exterior of rod-like members

A coating apparatus for coating an outer peripheral surface of a rod-shaped workpiece with a covering material, comprising an elastic body having a covering material-impregnatable property and provided with an insertion hole through which the workpiece is to be passed, and a moving mechanism for moving the workpiece relative to the elastic body through the insertion hole, wherein the outer peripheral surface of the workpiece is coated with the covering material impregnated in the elastic body, when the workpiece is passed through the insertion hole of the elastic body by the moving mechanism.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a covering material-coating apparatus and 
a covering material-coating method. 
2. Related Art of the Invention 
Heretofore, for example, when a lightning-guard insulator apparatus is to 
be assembled or produced, a lightning arresting element is placed in an 
insulating cylinder made of a fiber-reinforced plastic (FRP), and 
electrode fittings are attached to both ends of the insulating cylinder. A 
covering material such as a primer (an undercoat such as an adhesive) is 
coated around the outer periphery of the insulating cylinder, and then an 
insulating housing is molded of silicone rubber or the like around the 
insulating cylinder. 
When the coating material such as a primer is to be applied to the outer 
periphery of the insulating cylinder at the time of assembling such a 
lightning-guard insulator, it is a conventional practice that while a 
worker is turning the insulating cylinder successively by 120.degree., a 
gauze impregnated with the primer is contacted with the insulating 
cylinder and moved thereon in the circumferential and longitudinal 
directions to manually effect the coating by three times. When no 
primer-coated portion is to be formed around the outer periphery of each 
of the opposite ends of the insulating cylinder corresponding to the 
electrode fittings, the coating is effected in the state that a masking 
tape is adhered there. 
However, according to the above conventional process, since the primer is 
manually applied to the workpiece, the coating work is time-consuming, and 
it is difficult to uniformly coat the primer on the outer peripheral 
surface of the workpiece. 
Further, according to the above conventional process, since the masking 
tape is adhered to those outer peripheral end portions of the workpiece 
where no primer is to be coated, it is troublesome and time-consuming to 
adhere or remove the tape. 
SUMMARY OF THE INVENTION 
The present invention has been accomplished with due attention to the 
problems existing as in the above incoventional technique. A principle 
object of the present invention is to provide a covering material-applying 
apparatus and a covering material-applying process which can efficiently 
and uniformly apply the covering material upon the outer periphery of a 
rod-shaped workpiece. 
Another object of the present invention is to provide a covering 
material-applying apparatus which can easily form an outer peripheral end 
portion of the workpiece where no coating material is applied. 
In order to accomplish the above objects, the coating apparatus according 
to the present invention for coating an outer peripheral surface of a 
rod-shaped workpiece with a covering material, comprises an elastic body 
having a covering material-impregnatable property and provided with an 
insertion hole through which the workpiece is to be passed, and a moving 
mechanism for moving the workpiece relative to the elastic body through 
the insertion hole, wherein the outer peripheral surface of the workpiece 
is coated with the covering material impregnated in the elastic body, when 
the workpiece is passed through the insertion hole of the elastic body by 
the moving mechanism. 
Further, the present invention is to provide a process for coating an outer 
peripheral surface of a rod-shaped workpiece with a covering material by 
inserting the workpiece through an insertion hole formed in a central 
portion of elastic body and moving the workpiece relative to the elastic 
body in a longitudinal direction of the workpiece. 
According to the apparatus and the process for coating the outer periphery 
surface of the workpiece with the covering material in the present 
invention mentioned above, the rod-shaped workpiece is passed through the 
insertion hole of the elastic body impregnated with the covering material 
such as a primer, in this state the workpiece is moved relative to the 
elastic body in the longitudinal direction of the workpiece by the 
workpiece-moving mechanism, and thereby the outer peripheral surface of 
the workpiece is coated with the covering material impregnated into the 
elastic body. Therefore, the outer peripheral surface of the workpiece can 
be coated with the covering material in a short time to enhance the 
workability. Further, the outer peripheral surface of the workpiece can be 
uniformly coated with the covering material to enhance the quality of the 
product. 
In the following, preferred embodiments of the present invention will be 
explained. Any of these preferred embodiments may be combined together 
unless any unacceptable effect occurs. 
(1) The coating apparatus further comprises a rotating mechanism for 
rotating the workpiece. In this case, the outer peripheral surface of the 
workpiece is coated with the covering material by moving the workpiece 
relative to the elastic body through the insertion hole in the 
longitudinal direction of the workpiece, while the workpiece is being 
rotated by the rotating mechanism. Therefore, the outer peripheral surface 
of the workpiece can be more uniformly coated with the covering material 
in a shorter time period. Thereby, the workability and the product quality 
can be further enhanced. 
(2) The coating apparatus comprises a workpiece detecting mechanism for 
detecting an end portion of the workpiece and outputting a detection 
signal upon detection of said end portion of the workpiece so that the 
workpiece-moving mechanism may be stopped at a place corresponding to a 
location where the the elastic body is spaced from the end portion of the 
workpiece by a given distance, thereby to stop the relative movement 
between the workpiece and the elastic body and to not coat an outer 
peripheral surface of the end portion of the workpiece with the covering 
material. In this case, the sensor detects the end portion of the 
workpiece and outputs the detection signal when the workpiece comes to the 
place corresponding to a location where the the elastic body is spaced 
from the end portion of the workpiece by a given distance. Thereby, the 
relative movement between the workpiece is stopped and the elastic body to 
stop the coating action of the workpiece with the elastic body, and 
thereby an outer peripheral surface of the end portion of the workpiece 
not coated with the covering material is formed. Therefore, such an outer 
peripheral surface of the end portion of the workpiece not coated with the 
covering material can be easily formed with no use of a masking tape. 
Thereby, the workability can be largely enhanced. 
(3) The elastic body includes two elastic members divided along the 
insertion hole so that said insertion hole may be opened by spacing the 
elastic members from each other. Since the elastic body is divided into 
two elastic members, the insertion hole can be opened along its 
longitudinal direction by spacing the elastic members from each other. 
Therefore, the workpiece can be easily attached to and detached from the 
insertion hole in the state that the insertion hole is kept opened. 
(5) The elastic body is sandwiched by a sandwiching member from opposite 
sides of the elastic body as viewed in a moving direction of the 
workpiece, said sandwiching member being made of a material harder than 
the open-cell type sponge. In this case, the elastic body can be prevented 
from being deformed in shape during relative movement between the elastic 
body and the workpiece. 
(6) The coating apparatus further comprises a vertically movably concaved 
cylindrical supporting roller having a recessed portion at a central 
portion of an outer periphery thereof, said supporting roller being 
adapted to support the workpiece coated with the covering material. In 
this case, as the the outer peripheral surface of the workpiece is coated 
with the covering material by moving the workpiece relative to the elastic 
body with the moving mechanism, the concaved cylindrical supporting roller 
is moved up to the workpiece-moving path to support the coated portion of 
the workpiece at the recessed portion of the central outer peripheral face 
of the supporting roller. Therefore, the coated workpiece can be supported 
by the supporting roller in the state that the coated surface of the 
workpiece is not largely touched. The term "concaved cylindrical 
supporting roller" means, for example, the shape shown in FIGS. 1, 2, 4 
and 6 which is formed by joining two frusto-conical bodies at their 
smaller diameter portions. 
(7) The coating apparatus further comprises a hot air generating mechanism 
arranged downstream the elastic body to dry the covering material coated 
upon the outer peripheral surface of the workpiece. In this case, after 
the outer peripheral surface of the workpiece is coated with the covering 
material by passing the workpiece through the insertion hole, hot air is 
fed upon the covering material-coated surface of the workpiece by the hot 
air generating mechanism. Therefore, the covering material coated upon the 
outer peripheral surface of the workpiece can be dried in a short time. 
(8) The coating apparatus further comprises a workpiece feeding mechanism 
and a workpiece feeding guide mechanism, said workpiece feeding mechanism 
being adapted for feeding the workpiece to the elastic body and said 
workpiece feed guide mechanism being adapted for guiding a forward end of 
the workpiece of the workpiece into the insertion hole of the elastic 
body. In this case, the steps of feeding the workpiece to the elastic body 
and aligning and guiding the starting end of the workpiece to the 
insertion hole of the elastic hole can be easily effected without 
necessitating a large manual labor. 
(9) The coating apparatus further comprises a chucking mechanism for 
chucking a forward end portion of the workpiece, said chucking mechanism 
being moved by said workpiece-moving mechanism to pass the workpiece 
through the insertion hole of the elastic body. In this case, the 
workpiece can be assuredly moved through the insertion hole of the elastic 
body to facilitate the coating operation. 
(10) The coating apparatus further comprises a moving mechanism 
movement-detecting mechanism for detecting a location where the coating of 
the workpiece with the covering material through the insertion hole of the 
elastic body is to be terminated so as to stop the workpiece-moving 
mechanism. In this case, the coating step can be stopped at any arbitrary 
location of the workpiece, so that an end portion of the workpiece to 
which an end fitting is to be attached may be left uncoated with the 
covering material. 
These and other objects, features and advantages of the invention will be 
appreciated upon reading of the following description of the invention 
when taken in conjunction with the attached drawings, with the 
understanding that some modifications, variations and/or changes could be 
easily made by the skilled person in the art to which the invention 
pertains.

DETAILED DESCRIPTION OF THE INVENTION 
An embodiment of the covering material-coating apparatus according to the 
present invention will be explained below with reference to the attached 
drawings. 
First, this embodiment of the covering material-coating apparatus will be 
schematically explained with reference to FIGS. 1 to 3. As shown, a 
machine frame 11 extending horizontally is placed on a floor via plural 
supporting legs 12, and a pair of parallel rails 13 are horizontally laid 
on the upper surface of the machine frame 11 in a longitudinal direction. 
A workpiece feeding mechanism 14 is arranged on a forward side of the 
machine frame 11, and includes a conveyor frame 15 placed on the floor via 
plural supporting legs 16 and plural conveyor rollers 17 rotatably 
supported on the conveyor frame 15 at a given interval. A rod-shaped 
workpiece 18 having a circular section is supported on the conveyor 
rollers 17 of the workpiece feed mechanism 14 so that the workpiece 18 may 
be carried and fed above the machine frame 11. 
A coating mechanism 19 is provided at an upper face of a front end portion 
of the machine frame 11 (at the upper face of a left end portion in FIGS. 
1 and 3). The coating mechanism 19 includes an elastic body 20 made of an 
open-cell sponge, which is provided in its central portion with a 
insertion hole 21 for inserting the workpiece 18 therethrough. For 
example, the insertion hole 21 has such a size that the elastic body 20 
may press the outer periphery of the workpiece 18 at the inner peripheral 
wall of the insertion hole 21 during the passage of the workpiece through 
the insertion hole 21, while the elastic body 20 is not largely deformed 
near the insertion hole 21. A primer feed tank 22 is arranged near above 
the coating mechanism 19, and a primer as a covering material placed in 
the tank 22 is fed into the elastic body 20 via a feed pipe 23 so that the 
elastic body 20 may be impregnated with the primer. In this embodiment, as 
a primer is used a silicone rubber dissolved in an organic solvent such as 
toluene (tradename S2260 or SH2260 manufactured by Torey Dow Corning 
Silicone Co., Ltd.). 
A feed/guide mechanism 24 for the workpiece 18 is arranged near in front of 
the coating mechanism 19, and guides the workpiece 18 through the 
insertion hole 21 of the elastic body 20. A moving table 25 is movably 
supported on a pair of the rails 13 of the machine frame 11, and above the 
moving table 25 are arranged a chucking mechanism 26, a turning mechanism 
27 and a carrying mechanism 28 for the workpiece 18. A starting end 
portion of the workpiece 18 inserted through the insertion hole 21 of the 
elastic body 20 in the coating mechanism 19 is releasably chucked by the 
chucking mechanism 26. While the workpiece 18 is chucked by the chucking 
mechanism 26, the workpiece 18 is turned around its axis by the turning 
mechanism 27, and the moving table 25 is carried by the moving mechanism 
28 in a rear direction (to a right side in FIGS. 1 and 3) to carry the 
workpiece 18 in the longitudinal direction. By so doing, the workpiece 18 
is rotated and moved relative to the elastic body 20 through the 
through-hole 21, so that the primer impregnated into the elastic body 20 
is applied around the outer periphery of the workpiece 18. 
A hot air generating mechanism 29 is arranged under the front end portion 
of the machine frame 11, corresponding to the coating mechanism 19. The 
hot air generating mechanism 29 includes a blower 30 with a motor, a 
heater 31 connected to a discharge side of the blower 30, and a feed duct 
32 connected to the heater 31 and opened above a rear side of the coating 
mechanism 19. After the primer is applied onto the outer periphery of the 
workpiece 18 by the coating mechanism 19, hot air generated in the heater 
31 is blown upon the primer-coated surface of the workpiece 18 through the 
opening of the feed duct 32, thereby drying said coated surface. 
A plurality of work-moving guide mechanisms 33 are provided at the machine 
frame 11 such that the mechanisms 33 may be located at a given interval 
along a moving path of the moving table 25. Each moving guide mechanism 33 
includes a support roller 34 having a liftable concaved barrel shape 34 
with an annular recess 34a on a central portion of the outer periphery. 
When the outer peripheral surface of the workpiece 18 is coated with the 
primer in the state that the workpiece is being moved by the moving 
mechanism 28 and every time the moving table 25 passes above the moving 
guide mechanism 33, the supporting rollers 34 are successively raised to 
support the workpiece 18 on the recesses 34a. 
As shown in FIG. 3, the workpiece-detecting mechanism 35 is arranged in 
front of the feed guide mechanism 24, and includes a first sensor 36 and a 
second sensor 37. The first sensor 36 includes a light-emitting element 
36a and a light-receiving element 36b, and the second sensor 37 includes a 
light-emitting element 37a and a light-receiving element 37b. The 
workpiece 18 is moved by the moving mechanism 28. When the terminal end of 
the workpiece 18 is moved to be opposed to the first sensor 36, the 
light-receiving element 36b outputs a detection signal, based on which a 
moving speed of the moving mechanism 28 is reduced. When the terminal end 
of the workpiece 18 is moved to be opposed to the second sensor 37, the 
light-receiving element 37b outputs a detection signal, based on which the 
moving mechanism 28 is stopped. By so doing, a portion P1 not coated with 
the primer as shown in FIG. 1 is formed around an outer periphery of the 
terminal end portion of the workpiece 18. 
As is seen in FIG. 1, after the workpiece 18 is set at the coating 
mechanism 19 and the chucking mechanism 26, the moving table 25 begins to 
be moved to make the coating mechanism 19 coat the workpiece 18 with the 
primer. Thus, a portion P2 not coated with the primer is formed at an 
outer periphery of the starting end portion of the workpiece 18. 
As shown in FIG. 3, a movement detecting mechanism 38 for the moving table 
25 is arranged corresponding to a moving path of the chucking mechanism 
26. This movement detecting mechanism 38 includes a dog 39 projecting from 
the chucking mechanism 26 and first to third approach switches 40, 41 and 
42 to be opposed to the dog 39. When the chucking mechanism 26 by which 
the workpiece 18 is chucked is moved to its movement terminal end by the 
moving mechanism 28, the dog 39 is opposed to the first approach switch 40 
so that the first approach switch 40 may output a detection signal to 
restrict the location of the movement terminal end of the chucking 
mechanism 26. 
As the chucking mechanism from which the workpiece 18 is released after 
being coated is returned from the location of its movement terminal end to 
its original location, the dog 39 is opposed to the second approach switch 
41 so that the second approach switch 41 may output a detection signal to 
reduce a returning speed of the moving mechanism 28. Thereafter, when the 
dog 39 is opposed to the third approach switch 42, the third approach 
switch 42 outputs a detection signal to stop the returning movement of the 
moving mechanism 28. 
Next, the above mentioned mechanisms will be explained in more detail. 
First, the coating mechanism 19 will be explained. As shown in FIGS. 4 and 
5, a supporting plate 45 is liftably supported above the machine frame 11 
via a pair of guide rods 46 and a lift cylinder 47. The supporting frame 
45 is moved, by actuating the lift cylinder 47, between an upper location 
corresponding to the location of the workpiece 18 and a lower location 
spaced from that location of the workpiece 18. A receiving vessel 48 is 
arranged on the upper face of the supporting plate 45 via a receiving tray 
49, and is binarily divided into a lower vessel 48a and an upper vessel 
48b. The lower vessel 48a is fixed to the supporting plate 45 via the 
receiving tray 49, and the upper vessel 48b is arranged above the lower 
vessel 48a via supporting arms 50 and 51 and a supporting shaft such that 
the upper vessel 48b may be opened or closed relative to the lower vessel 
48a. At a top portion of the upper vessel 48b is formed a feed opening 53 
to be connected to a primer feed pipe 23, and at a side wall of the lower 
vessel 48a is formed an overflow opening 54 for overflowing the primer. 
The elastic body 20 made of open-cell sponge is vertically and binarily 
divided into lower and upper elastic members 20a and 20b along the 
insertion hole 21. The lower and upper elastic members 20a and 20b are 
exchangeably received in the lower and upper vessels 48a and 48b of the 
receiving vessel 48, respectively. Sandwiching bodies 55 made of an 
elastic material such as rubber harder than that of the open-cell sponge 
are joined to the opposite side faces of the elastic body 20 so that the 
sandwiching bodies 55 may sandwich the elastic body 20 from opposite sides 
along the moving direction of the workpiece. In a central portion of each 
of the sandwiching bodies 55 is formed a through-hole 56 tapered as shown, 
corresponding to the insertion hole 21 of the elastic body 20. Each 
sandwiching body 55 is binarily divided into a lower sandwiching member 
55a and an upper sandwiching member 55b along the through-hole 56 as is 
the same with the elastic body 20. 
An opening/closing cylinder 57 is rotatably supported at the supporting arm 
50 fixed to the lower vessel 48a, and a piston rod 57a is connected to the 
supporting arm 51 at the upper vessel 48b. When the opening/closing 
cylinder 57 outwardly projects the piston rod 57a, the upper vessel 48b is 
turned to a closing position above the lower vessel 48a as shown by solid 
lines in FIG. 5 so that the insertion hole 21 is closedly formed inside 
the elastic body 20 to allow the insertion of the workpiece 18 
therethrough. When the opening/closing cylinder 57 retracts the piston rod 
57a, as shown by two-dotted lines in FIG. 5, the upper vessel 48b is 
turned to an upper opened location, so that the insertion hole 21 of the 
elastic body 20 is opened to allow setting and releasing of the workpiece 
18 relative to the insertion hole 21. 
As shown by a two-dotted line in FIG. 5, the primer fed inside the 
receiving vessel 48 through the feed opening 53 is stored inside the lower 
vessel 48a at a given level L1, and excess primer is overflown into the 
receiving tray 49 through the overflow opening 54. In this state, the 
workpiece 18 is rotated by the rotating mechanism 27 and moved by the 
moving mechanism 28 through the insertion hole 21 of the elastic body 20. 
Consequently, the primer is applied to the outer peripheral surface of the 
workpiece 18 mainly by the lower elastic body 20a, and the entire 
peripheral surface of the workpiece 18 is coated with the primer in a 
uniform thickness by the upper elastic member 20b. The rotating speed of 
the workpiece 18 by the rotating mechanism and the moving speed of the 
workpiece 18 by the moving mechanism 28 are so set that the primer may be 
applied upon the outer peripheral surface of the workpiece 18 twice during 
the coating. 
Next, the workpiece feeding guide mechanism 24 will be explained. As shown 
in FIGS. 4 and 6, a bracket 60 is erected on the machine frame 11, and a 
fitting plate 61 is fixed to a side portion of the bracket 60. A 
supporting roller 62 is rotatably supported above the fitting plate 61 via 
a supporting plate 63 such that the supporting roller 62 may be turned 
around a axis S1 shifted relative to the moving direction of the workpiece 
18 at a given angle (45.degree. in this embodiment). The supporting roller 
62 has a concaved barrel shape, and an annular recess 62a is formed in a 
central portion of the outer periphery. As shown in FIG. 6, the workpiece 
18 is slidably supported by the recess 62a of the supporting roller 60, 
and is led through the insertion hole 21 of the elastic body 20 in the 
coating mechanism 19. 
A fitting plate 64 is fixed to an upper end of the bracket 60, and a lift 
plate 66 is liftably supported under the fitting plate 64 via a pair of 
guide rods 65. A press roller 67 is rotatably supported under the lift 
plate 66 via a supporting plate 68 such that the supporting roller 67 may 
be turned around a axis S2 shifted relative to the moving direction of the 
workpiece 18 at a given angle (45.degree. in this embodiment) in an 
opposite shift direction of the axis S1. As is the same with the 
supporting roller 62, the supporting roller 67 has a concaved barrel 
shape, and an annular recess 67a is formed in a central portion of the 
outer periphery. 
Under the fitting plate 64 is fitted a lift cylinder 69, which moves up and 
down the lift plate 66 to displace the press roller 67 away from or near 
to the supporting roller 62. As the press roller 67 is moved nearer to the 
supporting roller 62, the press roller 67 is descended down to a location 
where the recess 67a contacts the upper peripheral surface of the 
workpiece 18 depending upon the outer diameter of the workpiece 18. In 
this state, the workpiece 18 is sandwiched between the rollers 62 and 67. 
Further, the press roller 67 is moved apart from the supporting roller 62, 
the upper side of the supporting roller 62 is opened to allow the setting 
or detaching of the workpiece 18 relative to the recess 62. 
Next, the above workpiece-chucking mechanism 26 will be explained. As shown 
in FIGS. 7 and 8, a pair of rails 72 are provided on the upper face of the 
moving table 25, and extends in the same direction of the rails 13 on the 
machine frame 11. A supporting plate 73 is movably supported upright on 
the rails 72, and a through-hole 73a is formed in a central portion of the 
supporting plate 73. A pair of guides 73b are vertically extended in 
parallel at side portions of the supporting plate 73. A fitting plate 74 
is vertically movably supported between the guides 73b of the supporting 
plate 73, and a bearing cylinder 75 is provided on one side of the fitting 
plate 74 through the through-hole 73a, whereas a gear box 76 is fixed to 
the other side thereof. A cylindrical rotary shaft 77 is rotatably 
supported in the bearing cylinder 75 via a pair of bearings 78, and to a 
tip of the rotary shaft 77 is fitted a chucking head 79 having a plurality 
of chucking claws 79a. 
An air port 80 is fitted to a base end of the rotary shaft 77, and air is 
fed to or discharged from a chuck opening/closing mechanism (not shown) 
inside the chucking head 79 through the rotary shaft 77 from the air port 
80 to open or close the chucking claws 79. When the chucking claws are 
closed, the starting end portion of the workpiece 18 is chucked between 
the chucking claws 79. On the other hand, when the chucking claws 79a are 
opened, the workpiece 18 can be set to or detached from between the chuck 
claws 79a. 
A guide plate 81 is elected above the moving table 25 via a fitting plate 
82, corresponding to the chuck head 79, and at an upper end of the guide 
plate 81 is provided a V-shaped recess 81a for guiding the starting end 
portion of the workpiece 18 between the chucking claws 79. A moving 
cylinder 83 is fitted to a side face of the fitting plate 82, and a piston 
rod 83a is connected to the supporting plate 73. When the moving cylinder 
83 retracts the piston rod 83a, the supporting plate 73 is moved to the 
left side in FIG. 7 so that the chucking head 79 may be located at a 
location where the starting end portion of the workpiece 18 is chucked. 
When the moving cylinder 83 outwardly projects the piston rod 83a, the 
supporting plate 73 is moved to the right side of the in this Figure so 
that the chucking head 79 may be located at a location where the workpiece 
18 is released from the chucking head. 
An adjusting screw 84 is rotatably supported by an upper end of the 
supporting plate 73 and screwed to the fitting plate 74 at a lower end 
portion, whereas its upper end is provided with an operating handle 85. As 
the adjusting screw 84 is turned by the operating handle 85, the fitting 
plate 74, the bearing cylinder 75 and the gear box 76 are vertically and 
integrally moved so that the axis of the rotary shaft 77 may be aligned 
with that of the workpiece 18. Therefore, if the outer diameter of the 
workpiece 18 is changed, the chucking head 79 can be easily moved to a 
location conforming with the starting end portion of the workpiece 18. 
Next, the workpiece-rotating mechanism 27 will be explained. As shown in 
FIGS. 7 and 8, a rotary motor 88 is fitted to an outer face of the gear 
box 76, and its motor shaft 88a projects into the gear box 76. A driving 
gear 89 is fitted to the motor shaft 88, and a driven shaft 90 is fitted 
to the rotary shaft 77 and meshes with the driving gear 89. While the 
workpiece 18 is chucked between the chucking claws 79a of the chucking 
head 79, the motor 88 rotates the rotary shaft 77 via both the gears 89 
and 90 to exert a rotary force upon the workpiece 18. 
Next, the workpiece-moving mechanism 28 will be explained. As shown in 
FIGS. 7 and 8, a rack 93 is fitted to a side portion of the machine frame 
11, and extends in the same direction as the rails 13. A moving motor 94 
is arranged above the moving table 25 via a bracket 95, and a motor shaft 
94a projects from the under face of the motor 94. A pinion 96 is fitted 
around the motor shaft 94a of the moving motor 94, and meshes with the 
rack 93. 
When the moving motor 94 is rotated in one direction in the state that the 
workpiece 18 is being chucked between the chucking claws 79a of the 
chucking head 79, the moving table 25 is moved to the right side in FIGS. 
1 and 2 via the pinion 96 and the rack 93 so that the workpiece 18 may be 
moved to the same side. After the workpiece 18 is released from the 
chucking claws of the chucking head 79 at the location of the movement 
terminal end, the moving motor 94 is rotated in the reverse direction so 
that the moving table 25 may be moved back to the original position via 
the pinion 96 and the rack 93. 
Next, the work-moving guide mechanism 33 will be explained. As shown in 
FIGS. 1 to 3, a lift plate 99 is vertically movably supported by the 
machine frame 11 via a pair of guide rods 100. The above supporting roller 
34 is supported above the lift plate 99 via a supporting plate 101 such 
that the supporting roller 34 may be rotatable around an axis S3 shifted 
at a given angle (45.degree. in this embodiment), relative to the moving 
direction of the workpiece 18, in the same direction of the supporting 
roller 62 of the feeding guide mechanism 24. 
A lift cylinder 102 is fitted to the under face of the machine frame 11, 
and its piston rod 102a is connected to the lift plate 99. While the 
workpiece 18 is being moved by the moving mechanism 28, the primer is 
applied around the outer peripheral surface of the workpiece 18. At that 
time, as shown by the two-dotted lines in FIG. 2, every time the moving 
table 25 passes above each moving guide mechanism 33, the lift cylinder 
102 outwardly projects the piston rods 102a to move up the lift plate 99. 
By so doing, the workpiece 18 is supported by the recess 34a of the 
supporting roller 34 having the almost concaved barrel shape, while its 
coated surface does not largely contact the supporting roller 34. 
The operation of the primer-coating apparatus thus constructed will be 
explained. 
When a workpiece-setting switch on an operation panel not shown is turned 
on, in the coating mechanism 19, the receiving vessel 48 is moved 
downwardly to its lower position by the lift cylinder 47, and the upper 
vessel 48b is turned to its open location above the lower vessel 48a by 
the lift cylinder 47. In the chucking mechanism 26, the chucking head 79 
is moved to the left chucking position from its original position shown in 
FIG. 1 by the moving cylinder 83. At that time, the chucking claws 79a of 
the chucking head 79 are kept opened. 
In this state, the workpiece 18 is fed and set between the chucking claws 
79 of the chucking head 79 in the chucking mechanism 26 through both the 
vessels 48a and 48b in the coating mechanism 19 by means of the roller 
conveyor 17 of the workpiece-feeding mechanism 14. Thereafter, when a 
start switch on the operation panel not shown is turn on, in the coating 
mechanism 19, the receiving vessel 48 is moved from its lower position to 
its upper position by the lift cylinder 47, and the upper vessel 48b is 
turned to its closing position above the lower vessel 48a by the 
opening/closing cylinder 57. By so doing, the upper elastic member 20b is 
closely contacted with the lower elastic member 20a so that the through 
hole 21 may be formed between both the elastic members 20a and 20b. The 
workpiece 18 is inserted through the insertion hole 21. 
At that time, air is fed to the not shown opening/closing mechanism inside 
the chucking head 79 in the chucking mechanism 26 from the air port 80 
through the rotary shaft 77 to close the chucking claws 79a. Thereby, the 
start end portion of the workpiece 18 is chucked between the chucking 
claws 79a. In the workpiece-feeding guide mechanism 24, the pressing 
roller 67 is moved down by the lift cylinder 69 so that the workpiece 18 
may be sandwiched between the supporting roller 62 and the pressing roller 
67. 
In this state, the primer is fed into the receiving vessel 48 of the 
coating mechanism from the primer tank 22 to immerse the elastic body 20. 
While the moving mechanism 28 is kept stopped, the rotary shaft 77 is 
turned by the rotating motor 88 of the rotating mechanism 27 so that the 
workpiece 18 may be turned via the chucking head 79 for a given time 
period only. By so doing, the primer is wet-coated on the outer peripheral 
surface of the workpiece 18 in the state that the workpiece contacts the 
inner periphery of the insertion hole 21 of the elastic body 20. At that 
time, as shown in FIG. 1, since the elastic body 20 of the coating 
mechanism 19 slidably contacts the workpiece 18 at a location spaced from 
the starting end by a given distance, a portion P2 not coated with the 
primer is formed around the outer peripheral surface of the starting end 
of the workpiece 18. 
After a predetermined time lapses following the start of the coating, the 
moving table 25 is moved rearwardly (to the right in FIGS. 1 to 3) by the 
moving motor 94 to move the workpiece 18 in the same direction. 
Consequently, while the workpiece 18 is being rotated, it is moved 
relative to the elastic body 20 of the coating mechanism 19 through the 
insertion hole 21, so that the primer impregnated into the elastic body 20 
is successively wet-on-wet coated twice onto the outer peripheral surface 
of the workpiece 18. At that time, hot air is blown upon the primer-coated 
surface of the workpiece 18 through the feed duct 32 from the hot air 
generating mechanism 29, so that the primer applied onto the outer 
peripheral surface of the workpiece 18 is dried in a short time. 
When the moving table 25 passes above the moving guide mechanism 32 during 
coating the primer around the workpiece 18, as shown in FIG. 2 by the 
two-dotted lines, the almost barrel-shaped supporting roller 34 is moved 
up by the lift cylinder 102 of the moving guide mechanism 33. Therefore, 
as the workpiece 18 is moved rearwardly, it is successively supported by 
the recesses 34a of the supporting rollers 34 of the moving guide 
mechanisms 33 while the coated surface of the workpiece is not largely 
contacted with the supporting rollers 34. 
As shown in FIG. 3 by the two-dotted lines, when the terminal end portion 
of the workpiece 18 is opposed to the first sensor 36 of the 
workpiece-detecting mechanism 35, the light-receiving element 36b outputs 
a detection signal, based on which the moving speed of the moving 
mechanism 28 is reduced. Thereafter, when the terminal end portion of the 
workpiece 18 is opposed to the second sensor 37, the light-receiving 
element 37b outputs a detection signal. Based on this detection signal, 
the movement of the moving mechanism 28 is stopped, and the operation of 
the hot air generating mechanism 29 is stopped. As a result, while the 
workpiece 18 is merely rotated, the primer is wet-on-wet coated upon the 
workpiece 18 at a location spaced from the terminal end by a given 
distance, the portion P1 of the workpiece being not coated with the 
primer. 
After a predetermined time lapses following the stoppage of the moving 
mechanism 28, the rotating mechanism 27 is stopped. At that time, in the 
coating mechanism 19, the upper vessel 48b is turned to the open location 
above the lower vessel 48a by the opening/ closing cylinder 57, while the 
receiving vessel 48 is moved to its lower position by the lift cylinder 
24. In the workpiece feeding guide mechanism 24, the press roller 67 is 
moved up apart from the upper outer peripheral surface of the workpiece by 
the lift cylinder 69. 
In the chucking mechanism 26, feeding of air into the opening/closing 
mechanism inside the chucking head 79 is stopped, so that the chucking 
claws 79a are opened to release the chucking of the workpiece 18. 
Thereafter, the supporting plate 73 is moved to the right side in FIGS. 1 
and 7 by the moving cylinder 83, and the chucking head 79 is moved to a 
location spaced from the starting terminal end of the workpiece 18. 
Therefore, in this state, the completely coated workpiece 18 can be easily 
taken out above from the support rollers 34 of the moving guide mechanism 
33. 
Then, when the return switch on the operation panel not shown is turned on, 
the supporting plate 73 is moved to the left side in FIGS. 1 and 7 by the 
moving cylinder 83 of the chucking mechanism 26, so that the chucking head 
79 is returned to the position for chucking the workpiece 18. At that 
time, the moving table 25 is moved forwardly (to the left side in FIGS. 1 
to 3) by the moving motor 94 of the moving mechanism 28, the chucking 
mechanism 26, the rotating mechanism 27 and the moving mechanism 28 are 
returned to their respective original positions. 
When the dog 39 of the movement detecting mechanism 38 is opposed to the 
second approach switch 41 during the above returning operation, the second 
approach switch 41 outputs a detection signal, based on which the 
returning speed of the moving mechanism 28 is reduced. Then, when the dog 
39 is opposed to the third approach switch 42, the third approach switch 
outputs a detection signal, based on which the returning operation of the 
moving mechanism 28 is stopped. In this state, an original 
point-indicating lamp is lit on the operation panel not shown, and the 
apparatus waits for setting of a next workpiece 18. 
As mentioned above, according to this embodiment of the primer-coating 
apparatus, while the rod-shaped workpiece 18 is inserted through the 
insertion hole 21 in the central portion of the elastic body 20, the 
workpiece and the elastic body 20 are moved relative to each other by the 
moving mechanism 28 to coat the primer impregnated into the elastic body 
20 around the workpiece 18. Therefore, the primer can be coated around the 
outer peripheral surface of the workpiece 18 in a short time to enhance 
the workability. Further, the coating quality can be improved. 
In addition, according to this embodiment of the primer-coating apparatus, 
when the workpiece 18 is to be coated with the primer, it is moved 
relative to the elastic body 20 by the moving mechanism 28 in the 
longitudinal direction, while being rotated by the rotating mechanism 27. 
Therefore, the primer can be uniformly coated upon the outer peripheral 
surface of the workpiece 18 in a shorter time period with the result that 
the workability and the coating quality can be enhanced. 
Furthermore, according to this embodiment of the primer-coating apparatus, 
as the workpiece 18 is coated with the primer, the sensor 37 outputs a 
detection signal when the elastic body 20 comes to be opposed to a given 
location of the workpiece spaced from the end of the workpiece 18 by a 
predetermined distance. Consequently, the moving mechanism 28 is stopped 
based on this detection signal. Therefore, the portion not coated with the 
primer can be easily formed around the outer peripheral surface of the end 
of the workpiece 18 without necessity of adhering a masking tape 
therearound. 
Further, according to this embodiment of the primer-coating apparatus, 
since the elastic body 20 is binarily divided into the lower elastic 
member 20a and the upper elastic member 20b, the insertion hole 21 can be 
opened by separating the upper elastic member 20b from the lower elastic 
member 20a. Therefore, while the insertion hole 21 is kept open, the 
workpiece 18 can be easily attached to or detached from the insertion hole 
21. 
Furthermore, according to this embodiment of the primer-coating apparatus, 
since the elastic body 20 is made of the open-cell type sponge, the primer 
can be fully impregnated into the entire elastic body 20. Therefore, the 
outer peripheral surface of the workpiece 18 can be uniformly coated with 
the elastic body 20 into which the primer is fully impregnated. 
In addition, according to this embodiment of the primer-coating apparatus, 
the elastic body 20 made of the open-cell type sponge is held between the 
sandwiching members 55 made of a material harder than the open-cell type 
sponge from the opposite side faces. Therefore, the shape of the elastic 
body 20 can be prevented from being deformed due to the relative movement 
between the workpiece 18 and the elastic body 20 during the coating. 
Furthermore, according to this embodiment of the primer-coating apparatus, 
when the primer is coated upon the outer peripheral surface of the 
workpiece 18 in the state that the workpiece 18 is being moved relative to 
the elastic body 20 by the moving mechanism 28, the almost barrel-shaped 
supporting rollers 34 are successively moved up to the moving path of the 
workpiece 18. Accordingly, the primer-coated workpiece 18 can be supported 
by the recesses 34a in the central portions of the outer peripheral faces 
of the respective supporting rollers 34 without being largely contacted 
with the support rollers. In addition, since the supporting roller 62 and 
the press roller 67 are inclined relative to the workpiece-passing path 
reversely at 45.degree., the workpiece 18 can be effectively prevented 
from slipping from the supporting roller. 
Further, according to this embodiment of the primer-coating apparatus, the 
primer is coated upon the outer peripheral surface of the workpiece 18 
when the workpiece 18 passes the insertion hole 21 of the elastic body 20, 
and then hot air is fed upon the primer-coated surface of the workpiece 18 
by the hot air generating mechanism 29. Therefore, the primer coated 
around the outer peripheral surface of the workpiece 18 can be dried in a 
short time. 
Modifications of the present invention can be made as follows. 
(a) Contrary to the above embodiment, the workpiece 18 is not moved, but 
instead the coating mechanism 18 with the elastic body 20 is moved by the 
moving mechanism 28 in the longitudinal direction of the workpiece 18 so 
that the primer impregnated into the elastic body 20 may be coated upon 
the outer peripheral surface of the workpiece 18. 
(b) By rotating the roller conveyors 17 of the workpiece feeding mechanism 
14 with use of a driving source such as a motor, the workpiece 18 can be 
automatically set to the coating mechanism 18 and the chucking mechanism 
26. 
(c) A workpiece discharging mechanism is arranged in parallel on a rear 
side of the machine frame 11 so that the workpiece 18 finishing its 
coating step and released from the chucking mechanism 26 may be 
automatically discharged from the work moving guide mechanism 33. 
(d) An adhesive or a paint is used instead of the primer as the coating 
agent. 
(e) A cylindrical workpiece is coated instead of the rod-shaped workpiece. 
In the following, the technical ideas encompassed by the present invention 
which can be grasped based on the above-mentioned embodiment will be 
explained. 
(1) The open-cell type sponge is received in the receiving vessel, and the 
receiving vessel is provided with the overflow opening to overflow the 
excess amount of the covering material impregnated into the open-cell type 
sponge. By so constructing, the covering material impregnated into the 
open-cell type sponge can be set at a given level inside the sponge so 
that the workpiece may be appropriately coated with the covering material. 
(2) The supporting rollers are provided at plural locations, and each 
supporting roller is moved up when the coated workpiece passes above the 
supporting roller. By so constructing, the coated workpiece can be 
smoothly supported. 
(3) The moving speed at which the workpiece is moved by the moving 
mechanism and the rotating speed at which the workpiece is rotated by the 
rotating mechanism are so set that the outer peripheral surface of the 
workpiece is wet-on-wet coated with the covering material. By so doing, 
the workpiece can be fully and assuredly coated with the covering material 
without leaving a uncoated outer peripheral surface portion of the 
workpiece. 
(4) A pair of the upper and lower almost concaved cylindrical supporting 
rollers each having a recessed portion at a central outer periphery are 
provided to sandwich the workpiece to be passed through the insertion 
hole. By so constructing, the workpiece can be smoothly fed into the 
insertion hole of the elastic body. 
(5) A pair of the above upper and lower almost concaved cylindrical 
supporting rollers have their rotary axes inclined relative to the moving 
path of the workpiece in reverse directions. By so constructing, the 
workpiece can be prevented from being slid so that the workpiece can be 
assuredly fed through the insertion hole of the elastic body.