Quick disconnect device

The present invention provides a quick disconnect coupling for a work tool to a machine. The invention in its preferred embodiment provides a coupling having fluid and electrical connections and also providing alignment independent of the locking mechanism. The present invention also is advantageous in that the locking mechanism is protected from the environment when the coupling halves are not mated and also prevents a false lock-up unless the halves of the coupling are mated and aligned.

FIELD OF THE INVENTION 
This invention relates to a coupling device and more particularly concerns 
an apparatus and method of utilization thereof of a quick disconnect 
device for coupling a work tool (or end of arm tooling device EOAT) to a 
machine (support or robot) and providing a quick disconnect for electrical 
and fluid connections 
DISCLOSURE STATEMENT 
This application is an improvement to the quick disconnect device disclosed 
in Douglas et al. U.S. Pat. No. 4,679,956 commonly It is known in the art 
to provide quick disconnect devices for coupling a work tool to a machine 
wherein the coupling (or locking mechanism is independent of the portions 
of the coupling which provide alignment. It is a desire of the present 
invention to provide a quick disconnect coupling as described in the 
above-noted application which provides a more simplified construction and 
also protects the coupling mechanism from the environment. 
Protection of the coupling mechanism from the environment is helpful since 
the coupling mechanism can sometimes be contaminated with particles from 
the environment such as dirt or metal shavings. Also it is desirable to 
protect the coupling mechanism from possible exposure to chemicals which 
over a passage of time can sometimes accumulate within the coupling 
mechanism or possibly have a corrosive effect. Another desire of the 
present invention is to provide a quick disconnect coupling which can not 
couple together unless the coupling halves are properly mated and aligned. 
Therefore, some means must be provided to prevent the coupling from being 
falsely activated to lock the coupling halves together when the coupling 
halves are not mated and properly aligned. 
SUMMARY OF THE INVENTION 
To meet the above-noted and other desires the present invention is brought 
forth. The present invention is a work-tool to work-station coupling 
device wherein alignment is independent of the coupling mechanism. The 
coupling mechanism has a closure which protects the coupling mechanism 
from the environment when the coupling halves are separated. The closure 
also functions to prevent operation of the coupling mechanism when the 
coupling halves are not aligned or mated. 
It is an object of the present invention to provide an apparatus and method 
of utilization thereof of a quick disconnect coupling for a work station 
and a work tool. 
It is also an object of the present invention to provide a quick disconnect 
coupling for connecting a tool to machine, including a tool adapter for 
holding the tool having a generally axial central cavity, and at least one 
generally axially orientated member bordering the central cavity and 
projecting towards the machine, and a tool changer adapted for 
sequentially mating and coupling with the tool adapter and connected with 
the machine, the tool changer including a shell with a generally axial 
interior chamber, a first passage fluidly connecting the outside of the 
shell and the interior chamber, and the interior chamber shell having at 
least one generally radial aperture intersecting the chamber axially 
separated from the first passage and towards the tool adapter, a piston 
slidably mounted in the interior chamber and responsive to a fluid fed 
into the interior chamber from the first passage, the piston having a rod 
portion with a cam portion adjacent the radial aperture, a locking member 
movably mounted within the radial aperture for interacting with the cam 
portion of the rod and the axially orientated member to couple the tool 
changer with the tool adapter, and closure means biased to a first 
position whereby the radial aperture is closed when the tool changer and 
the tool adapter are not mated and whereby the closure means is moved to a 
second position by the axially orientated member to open the radial 
aperture when the tool changer and the tool adapter are mated, the opening 
of the aperture allowing the piston to move to a position to cause the 
locking member to be captured between the cam portion of the rod and the 
axially orientated member to couple the tool changer with the tool 
adapter. 
It is also an object of the present invention to provide a quick disconnect 
coupling for coupling an EOAT to a robot, the coupling including a tool 
adapter connected with the EOAT having a generally axial central cavity, 
and a generally tubular axially orientated member bordering the central 
cavity projecting towards the robot having an interior flange at its end 
toward the robot and the tool adapter having a frusto conical surface on 
its end toward the robot, and a tool changer adapted for sequentially 
mating and coupling with the tool adapter along a frusto conical surface 
complementary to the tool adapter frusto conical surface and for 
connection with the robot, the tool changer including a cylindrical shell 
with a generally axial cylindrical interior chamber with an axial center 
line, a first and second passage connecting the outside of the shell and 
the interior chamber and the interior chamber having a plurality of 
generally radial apertures intersecting the chamber axially separated from 
the first passage and towards the tool adapter, a piston slidably mounted 
in the interior chamber dividing the interior chamber between the first 
and second passages and responsive to a fluid fed into the interior 
chamber from the first or second passages, the piston having an attached 
rod with a cammed portion having a 7.degree. cam angle with a line 
parallel with the axial center line of the interior chamber and the cam 
portion being adjacent to the radial apertures, a locking ball movably 
mounted within each of the radial apertures for interacting with the cam 
portion of the rod and the flange of the axially orientated cylinder to 
couple the tool changer with the tool adapter, and closure means including 
a fixed annular cover surrounding the interior chamber and a spring biased 
ring biased to a first position whereby the radial apertures are closed 
when the tool changer and the tool adapter are not mated and the spring 
biased ring being moved to a second position whereby the radial apertures 
are open by the axially orientated member when the tool changer and the 
tool adapter are mated, the opening of the aperture allowing the locking 
balls to be captured between the cam portion of the rod and the interior 
flange of the axially orientated member to couple the tool changer with 
the tool adapter. 
It is yet still another object of the present invention to provide a method 
of sequentially mating and coupling an EOAT connected with a tool adapter 
having a generally axial central cavity and at least one generally axially 
orientated member bordering the central cavity and projecting away from 
the EOAT, to a robot having a connected tool changer which includes a 
shell with a generally axial interior chamber including a first passage 
fluidly connecting the outside of the shell with the interior chamber, at 
least one generally radial aperture intersecting the interior chamber 
axially separated from the first passage and towards the tool adapter, a 
piston slidably mounted in the interior chamber and responsive to a fluid 
fed into the interior chamber from the first passage, the piston having an 
attached rod with a cam portion adjacent the radial aperture, a locking 
member movably mounted within the radial aperture for interacting with the 
cam portion of the rod and the axially orientated member to couple the 
tool adapter with the tool connector, closure means biased to a first 
position whereby the radial aperture is closed when the tool changer and 
the tool adapter are not mated and whereby the closure means is moved by 
the axial oriented member to a second position opening the radial aperture 
when the tool changer and the tool adapter are mated the opening of the 
aperture allowing the piston to move to a position causing the locking 
member to be captured between the cam portion of the rod and the axially 
orientated member to couple the tool changer with the tool adapter, the 
method including mating the tool adapter with the tool changer and 
aligning the tool adapter with the tool changer, contacting the axially 
orientated member of the tool adapter with the closure means of the tool 
changer to open the radial aperture, fluidly communicating the interior 
passage with the outside of the shell of the tool changer to move the 
piston, interacting the cam portion of the piston with the locking member 
whereby the locking member is forced outward contacting the axially 
orientated member of the tool adapter to couple the tool adapter with the 
tool changer. 
Other objects, desires and advantages of the present invention will become 
more apparent to those skilled in the art as the nature of the invention 
is better understood from the accompanying drawings and a detailed 
description.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring to FIG. 1 an EOAT 7 has connected thereto the female portion of 
the quick disconnect coupling 10 of the present invention commonly 
referred to as the tool adapter 11. Connected with the robot 14 is the 
male portion of the coupling commonly referred to as the tool changer 12. 
The tool changer is adapted for sequentially mating and coupling with the 
tool adapter 11. Referring additionally to FIGS. 2, 3, 4 and 5, the tool 
adapter 11 is connected with the EOAT 7 and provides fluid and electrical 
connections for the EOAT 7. The end of the tool adapter 11 towards the 
robot 14 (opposite the EOAT 7) has a cylindrical axial central cavity 13. 
The tool adapter 11 also has at least one generally axially orientated 
member 15 bordering the central cavity 13. As shown in FIGS. 1 and 2, 
axially oriented member 15 is tubular shaped having an inward facing 
flange 17. The tool adapter has a frusto conical surface 20b that 
surrounds and is radially spaced from the axially orientated member 15. 
The tool adapter 11 also has an electrical cable or lines 19a and connector 
21a. The electrical connector 21b illustrated provides thirteen lines 19b 
(commonly referred to as leads) with spring loaded contacts 70. Connectors 
21a, b and c are also made to be removable by removal of fasteners 71a, b 
and c for substitution of an electrical connector with a different amount 
of lines. 
For noncomingled fluidic coupling of air or hydraulic feeds, fluid lines 2 
are provided. Fluid lines 23 intersect surface 25 of the tool adapter 11. 
Hardened plate 24 has apertures 37 with inserted O-rings 90 (FIG. 2) to 
mate and seal fluid line 23 as it extends into the tool changer 12. 
The tool changer 12 has a cylindrical shell 94 which includes a cylinder 16 
and a back plate 18. The tool changer 12 has a frusto conical surface 20a 
that is complementary to the frusto conical surface 20b on the tool 
adapter 11. The tool changer 12 also is provided for rough alignment an 
axial locating pin 22. Locator plate 27 (FIG. 3) fixably connected with 
tool adapter 11 is provided to encircle locating pin 22. The tool changer 
12 has a generally axial interior chamber 26 formed by cylinder 16 and 
inner shell member 30, cap 32 and plug 34. 
Intersecting the interior chamber are first 36 and second 38 fluid passages 
usually provided for a pneumatic air control system. The interior chamber 
26 also has axially separated from the first 36 and second 38 passages, on 
an end of the tool changer away from the robot 14 (towards the tool 
adapter 11) a plurality of generally radial apertures 40 usually equally 
geometrically spaced. Slidably mounted within the interior chamber is a 
piston 42. The piston 42 has fixably attached thereto a rod 44 with an 
inclined cam portion 46. If desired, the piston 42 can be spring biased by 
a spring 96 captured between plug 34 and the piston 42. The piston 42 also 
has an O-ring 48 within an annular groove 47 of the piston which divides 
the interior chamber 26 into separate sealed sections. The piston rod 44 
also has a second annular chamber with an O-ring 50 which fluidly isolates 
the apertures 40 from the remainder of the interior chamber 26. Movably 
mounted within each radial aperture 40 is a locking member, typically a 
ball 52 to couple the tool changer 12 with the tool adapter 11. The piston 
has an actuated (FIG. 4) and a nonactuated (FIG. 1) position. In the 
nonactuated position, the piston 42 is in a generally retracted position 
and the balls 52 are allowed to move inwardly. In the extended coupling 
position, the cam portion 46 of the piston rod 44 interacts with the balls 
52 at a cam angle between 5.degree. and 9.degree. as illustrated in FIG. 4 
the cam portion 4b is at a 7.degree. cam angle. The cam angle can be 
defined as the angle between a line tangent to cam portion 46 and a line 
parallel to the axial center line 54 of the interior chamber 26. The 
interaction of the cam portion 46 of the piston rod 44 with the balls 52 
causes the balls 52 to be captured, between the cam portion 46 and the 
flange 17 of the axially orientated member 15 coupling the tool changer 12 
with the tool adapter 11. 
When the tool changer 12 and the tool adapter 11 are uncoupled, the 
apertures 40 are covered by a closure means 56 L-shaped ring 58 which is 
spring biased. The L-shaped ring 58 in the uncoupled position mates with a 
fixed annular cover 60, which surrounds the interior chamber 26 to seal 
apertures 40 from the environment. (Note in FIG. 1 the L-shaped ring 58 is 
shown in a pushed back position for clarity of illustration. However the 
L-shaped ring 58 would normally cover aperture 40 when the tool changer 12 
is uncoupled from the tool adapter.) 
It has usually been found that after coupling of the tool changer 12 with 
the tool adapter 11 the 7.degree. cam angle allows the coupling halves to 
be held together even when air pressure is not available from the passage 
36. The force exerted by spring 96 further ensures that the coupling 
halves are held together. A 7.degree. cam angle will cause the uncoupling 
force to be approximately eight (8) times greater than the force exerted 
on piston 42 by the differential fluid pressure of the first 36 and second 
38 passages (compensated by the differential areas of piston 42 by virtue 
of rod 44) and by the force exerted by the spring 96. 
To couple the tool adapter with the tool changer 12 the axially elongated 
member 15 first pushes the closure L-shaped ring 58 downward. The above 
action opens apertures 40, allowing the balls 52 to be pushed outward by 
the cam portion 46 of the piston rod 44. Therefore, whenever there is not 
proper alignment between the coupling halves, the axially elongated member 
15 can not push down the L-shaped ring 58 and the piston rod 44 will not 
be allowed to move to an activated position allowing the coupling halves 
to couple together. The above described feature prevents false coupling of 
the parts when alignment is not proper even when air pressure is present 
in first passage 36 since closures 40 are closed by L-shaped ring 58, 
preventing the outward movement of balls 52. To uncouple the coupling 
halves, pressurized air is connected with second passage 38, thereby 
retracting piston rod 44 against spring 96 and allowing balls 52 to move 
radially inward, thereby releasing axially elongated member 15. The tool 
adapter 11 is now released and can be removed. 
FIG. 6 is an alternate embodiment coupling 110 with parts similar to those 
illustrated in FIGS. 1-4 having the same referenced numerals prefixed by a 
1. Line 123 is sealed by a concentric O-ring 190 captured in a tapered 
aperture 37 of hardened plate 124. A bushing 250 concentric with the 
O-ring 190 and connected with tool adapter 111 is provided for mating and 
sealing with the O-ring 190. 
The bushing 250 has a diameter smaller than the minor diameter 237 of 
aperture 137. One advantage offered by this design is that there is a gap 
227 between surface 125 and the top surface 224 of plate 124. The gap 
allows room for dirt or other particles and prevents the particles from 
interfering with the sealing of line 23 or interfering with the mating of 
tool adapter 111 with tool changer 112. 
If surface 125 was used to mate and seal with O-ring 190 the compression of 
O-ring 190 would be limited to the cross sectional diameter of 0-ring 190 
minus the thickness of plate 124. However, bushing 250 with a diameter 
less than the minor diameter 237 of aperture 137 can now further compress 
0-ring 190 below the level of the top surface 224 of plate 124. The above 
configuration allows bushing 250 to further compress O-ring 190 to a 
thickness less than that of plate 124 providing better sealing. 
Since surface 125 no longer has to be flush with surface 224 (to compress 
0-ring 190) the taper of frusto conical surfaces 120a and 120b can now be 
formed near a 6.degree. instead of a 45.degree. angle (with axial center 
line 154). The 45.degree. angle was provided to assure the flush contact 
between surface 125 and plate 124 when the diameter of the tool adapter 
conical surface 120b was towards the upper end of its dimensional 
tolerance. Now by virtue of the 6.degree. taper if the tool adapter 111 is 
mated and coupled with the tool changer 112, the tool adapter 111 will not 
be permitted to separate from the tool changer 112 without relative axial 
movement between the tool adapter 111 and the tool changer 112 or 
deformation of one of the frusto conical surfaces 120or 120b. To 
illustrate the above a diametrically bisecting line 204 is drawn between a 
point of outermost contact 208 of frusto conical surfaces 120a and 120b 
and a point of innermost contact 206 of frusto conical surfaces 120a and 
120b. Moment force 205 influences tool adapter 111. Point 206 on surface 
frusto conical surface 120b will have to take the path of arc 205 if the 
tool adapter 111 and tool changer remain fixed at point 208. Therefore 
deformation of tool changer 112 frusto conical surface 120a must occur. 
Since separation cannot occur under the influence of moment forces without 
deformation, the coupling 110 is more prone to fail under an axial load. 
The above failure mode is desirable because of the previously explained 
approximately 8:1 axial force advantage of the coupling. 
It is an object of the present invention to provide a method of 
sequentially mating and coupling a tool 7 connected with a tool adapter 11 
having a generally axial central cavity 13 and at least one generally 
axially orientated member 15 bordering the central cavity 13 and 
projecting away from the tool 11, to a machine 14 having a connected tool 
changer 12 which includes a shell 94 with a generally axial interior 
chamber 26 including a first passage 36 fluidly connecting the outside of 
the shell 94 with the interior chamber 26, at least one generally radial 
aperture 40 intersecting the interior chamber axially separated from the 
first passage 36 and towards the tool adapter 11, a piston 42 slidably 
mounted in the interior chamber and responsive to a fluid fed into the 
interior chamber from the first passage 36, the piston having an attached 
rod 44 with a cam portion 46 adjacent the radial aperture 40, a locking 
member 52 movably mounted within the radial aperture 40 for interacting 
with the cam portion 46 of the rod 44 and the axially orientated member 15 
to couple the tool adapter 11 with the tool connector 12, closure means 56 
biased to a first position whereby the radial aperture 40 is closed when 
the tool changer 12 and the tool adapter 11 are not mated and whereby the 
closure means 56 is moved by the axially oriented member 15 to a second 
position opening the radial aperture 40 when the tool changer 12 and the 
tool adapter 11 are mated the opening of the aperture 40 allowing the 
piston 44 to move to a position causing the locking member 52 to be 
captured between the cam portion 46 of the rod 44 and the axially 
orientated member 15 to couple the tool changer 12 with the tool adapter 
11, the method including the following steps: 
1. Mating the tool adapter 11 with the tool changer 12 and aligning the 
tool adapter 11 with the tool changer 12; 
2. Contacting the axially orientated member 15 of the tool adapter 11 with 
the closure means 56 of the tool changer 12 to open the radial aperture 
40; 
3. Fluidly communicating the interior passage 36 with the outside of the 
shell 94 of the tool changer 12 to move the piston 42; 
4 Interacting the cam portion 46 of the piston with the locking member 52 
whereby the locking member 52 is forced outward contacting the axially 
orientated member 15 of the tool adapter 11 to couple the tool adapter 
with the tool changer 12. 
While an embodiment of the present invention has been explained it will be 
readily apparent to those skilled in the art of the various modifications 
which can be made to the present invention without departing from the 
spirit and scope of this application as it is encompassed by the following 
claims.