Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO 95/05975 PCT/CA94100450
Title: COUPLING AND ROBOTIC ENGAGEMENT FIBTURE AND
JAWS
Field of the Invention
This invention relates to connector interfaces
whereby an object can be seized and manipulated by a
tool, such as by the end effector of a robot. More
particularly, it relates to an interface fixture and
gripping anvil for such fixture that allows the gripping
anvil to be compatible with engagement of another form of
connector interface. The invention is particularly
suited to space applications.
Backctround to the Invention
In the field of materials handling, many types
of "handles" have been conceived. With the advent of
robotics, new types of handles or connector interfaces
suited for grasping by a robotic end-effector have become
required. Such interfaces should be easily graspable,
provide a degree of self-alignment and enable the
manipulated article to be transposed and rotated with
precision.
These requirements are especially present in
the case of space application where orbital replacement
(or replaceable) units - "ORU's" - are attached to space
vehicles and satellites, but are removable for servicing.
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Satellites themselves some times need to be grasped and
manipulated by robotic machines.
One type of interface has been designed for the
retrieval and perhaps the replacement of small component
parts - ORU's - as a means of servicing a satellite.
This interface is described in Patent Cooperation Treaty
Application No. PCT/CA91/0035, filed 3 October, 1991.
This "microfixture" interface is square in cross-section
in plan view, and from the a side view has a profile
defined by upper and lower chamfered walls that taper
into a waist, also square in a cross-sectional plan view,
defining two pairs of opposed corners. This specific
shape allows gripping anvils to receive and engage one
pair of the opposed, chamfered corners provided by this
square-waisted interface.
While the square-shaped microfixture interface
is useful for manipulating smaller objects, it is not as
satisfactory for gripping, holding and retrieving, for
example, an entire orbiting satellite as when the
satellite must be held for a servicing operation.
Previous attempts to provide an interface which
can be gripped sufficiently as, for example, transporting
or servicing a satellite, have been found to be prone to
jam and to be damaged, resulting in difficulties in
releasing the interface and to loss of accuracy in
alignment with the gripping anvils after repeated use.
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There is a need for a robust interface which
can be gripped sufficiently for, for example,
transporting or servicing a satellite, and which is not
prone to jam to be damaged.
There is also a need for an interface which
will provide no backlash when gripped firmly by gripping
anvils, and yet which will align with the gripping anvils
in all of the axis x, y and z axes. The present
invention provides such an interface.
There is further a need for gripping anvils
which can grip both the pre-existing design of
microfixture interface and the new robust interface
disclosed below, without the need for an adjustment being
made to one or both of the anvils.
The invention in its general form will first be
described, and then its implementation in terms of
specific embodiments will be detailed with reference to
the drawings following hereafter. These embodiments are
intended to demonstrate the principle of the invention,
and the manner of its implementation. The invention in
its broadest and more specific forms will then be further
described, and defined, in each of the individual claims
which conclude this Specification.
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Summary of the Invention
Accordingly to the present invention there is
provided a bifurcated connector interface suitable for
use with articles to be grasped, and particularly orbital
replacement units, comprising:
(1) an interface body; and
(2) two pairs of fingers extending outwardly from
opposite sides of the body, each pair of
fingers defining a bifurcation between their
inner sides in the form of a bifurcating
recess which tapers inwardly towards the body
the inner sides of the fingers being bevelled for
aligning with a pair of correspondingly shaped gripping
anvils that can enter the respective bifurcating recesses
for engagement with the interface.
Preferably, the bevelled inner sides of each of
the fingers define a shape f or the fingers that is in the
form of a truncated triangle in cross-section. Such
truncated triangle shape may be that of isosceles
triangle.
Strengthening webs may extend along the sides
of the body, joining the outer sides of the fingers.
The body is preferably pierced centrally,
perpendicularly to the plane of the fingers, by a
fastener access opening, whereby bolts and the like may
WO 95/05975 PCT/CA94/00450
be accessed. Such opening may also provide a seat for
such fasteners.
Mounting ribs may be provided on the underside
or base-end of the body for engagement with indexing
5 slots on the body, or ORU, to which the interface is
attached. Attachment is effected by attachment means
that may include mounting screw passages extending
downwardly through the body or strengthening portions of
the interface, preferably at positions adjacent the
outer, base or root-end sides of the fingers.
To complement the interface of the present
invention and, as well, serve as grippers for interfaces
of the microfixture type, gripping anvils may be
provided, each anvil comprising:
(a) an anvil body portion;
(b) a pair of splayed protuberances extending from
the anvil body portion for engaging an article
of complementary form, each pair of
protuberances having:
(i) opposed, inner sides defining between
them a converging recess formed by top
and bottom, chamfered, inner sides of the
protuberances, for mating with
complementary-shaped, converging, top and
bottom, inwardly chamfered walls,
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defining a waist, that meet to form a
corner on an article to be grasped: and
(ii) opposed, outer, notched sides with the
notches diverging rearwardly from one
another on the exterior portion of each
side of the recess, the notches being
positioned for mating with a pair of
diverging, top and bottom, bevelled
bifurcated fingers on an article to be
grasped.
Preferably, the central portions of the top and
bottom, chamfered, inner sides of the converging recess
are planar, and extend substantially vertically between
their chamfers to accurately align with similar, planar,
waist portions between the chamfers of the walls on the
micro-interface.
Preferably, the notches on the exterior sides
of the pairs of protuberances on the anvil each comprise
two, inwardly tapering, planar sides leading to a flat
bottom which accurately aligns with a flattened crest
between the top and bottom bevelled sides of the
bifurcated fingers on the article to be grasped.
The protuberances may have truncated ends to
reduce the risks of interferences and ensure mating in
both of the above (i) and (ii) modes.
PCT/CA94100450
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The foregoing summarizes the principal features
of the invention and some of its optional aspects. The
invention may be further understood by the description of
the preferred embodiments, in conjunction with the
drawings, which now follow.
Summary of the Figures
In the accompanying drawings which illustrate,
by way of example, an embodiment of the present
invention, Figure 1 is an oblique view of the connector
interface of the invention.
Figure 2 is an oblique view of one of a pair of
similar gripping anvils for gripping therebetween the
interface shown in Figure 1.
Figure 3 is an oblique view of a variant of the
anvil of Figure 2, carried on a mount for engagement with
a robotic machine.
Figure 4 is an oblique view of a prior art
micro-fixture connector interface.
Figure 5 is a top view of Figure 4.
Figure 6 is a side view of Figure 4.
Description of the Preferred Embodiment
In Figure 1 there is shown a bifurcated,
connector interface, generally designed 1, comprising a
body 2, and two pairs of splayed fingers 4,5 and 6,7,
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extending outwardly from root ends on opposite outer
sides of the body 2. Each pair of fingers 4,5 and 6,7
provides a bifurcation between their inner lateral sides
8,9 and 10,11 respectively, in the form of a recess, 12
and 14 respectively, which tapers inwardly towards the
centre of the body 2. All of the inner sides 8 to 11 of
the fingers 4 to 7 are bevelled for aligning with
gripping anvils of complementary shape (to be described
later) that will enter the recesses 12 and 14.
The bevelled inner sides 8 to 11 of the fingers
4 to 7 preferably, but not necessarily, provide a shape
to the inner portions of the fingers 4 to 7 that is that
of truncated triangles in cross-section. This is
apparent from the end view of the finger designated 7
where the truncated triangle is shown to be an isosceles
triangle. (The apparent curvature of the lines defining
the end of such finger 7 is due to the curved end face 7a
that terminates the outer end of the finger 7.)
Strengthening webs, such as that designated 16,
may extend along the two outer sides of the body 2
intermediate the finger pairs, joining outer sides of the
unit, such as between fingers 4 and 7.
A base, underside portion 18 of relatively
larger cross-section of the body 2 extends beneath the
fingers 4 to 7 and the strengthening webs, such as web
16, to serve as a base 18 for the body 2. Mounting ribs,
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such as those designated 20 and 22, are provided on the
underside of the body 2, and mounting screw passages 24,
25 extended downwardly through the strengthening webs,
such as web 16, and through the base portion 18 of the
body 2, preferably at positions adjacent the outer sides
of the fingers 4 to 7 at their root ends.
The interface 1 may be provided with lightening
recess in the form of indentations or blind holes 36,
37.
The interface 1 may also be provided with a pair of
tab-engaging recesses 42 on opposite sides of the top of
the body 2, and splayed protuberances 46 for the
interface 1 to be gripped by a hand tool (not shown).
A central attachment aperture 40 extends entirely
through the body 2 to provide access to attachment means
(not shown) such as bolts and machine screws or other
rotational fasteners. Such fasteners may attach an ORU
to an orbital body. If the aperture 40 has a seating rim
(not shown) near its bottom within the body 2,the
fastener may seat on the interface. By placing the
attachment aperture centrally in the body 2, robotic
end-effectors that rotate fasteners can anchor
themselves against the connector interface 1, using it
to absorb torgue.
Fins 28 may extend from the base 18 of the body 2
beneath the fingers 4 to 7 in order to form curtains
CA 02147654 2004-05-27
that will exclude tether-lines from snagging on the
interface.
While the interface 1 has been described in an
5 application suitable for orbiting body, it is equally
suited to any application whereby it is desired to
provide a connector interface to grasp and object with
gripping jaws.
In Figure 2, there is shown one of a pair of
10 similar gripping anvils for gripping the interface shown
in Figure 1. This anvil 29 comprises:
(a) a body portion 30;
(b) a pair of splayed protuberances 46, 47 each
having an exterior portion and extending from
the body portion 30, each pair of splayed
protuberances 46, 47 forming:
(i) a rearwardly converging central recess
48 between them, formed by top and
bottom chamfered, inner sides 45 and 49,
for, in operation, receiving, mating
with and gripping converging, inwardly
chamfered walls 51 and 52 of an
alternate interface 54 (Figures 4 to 6)
that meet at a corner 53 on the
alternate coupling interface 54; and
(ii) opposed, outer, notched sides 55 and 56
having notches 57, 58 formed therein,
such notches 57, 58 diverging rearwardly
from one another on each side of the
WO 95/05975 PCT/CA94/00450
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central recess 48, the notches 57, 58 in
operation, entering between, mating with
diverging, outwardly bevelled fingers 7,
8, 9, 10 on connector interface 1 (Figure
1)
The inner sides 45, 49 of the central recess 48
of the anvil 29 are planar between the chamfers and
extend substantially vertically, to accurately locate
with similar, planar waist portions 59, 66 between the
chamfers of the walls 51, 52 on the alternate interface
article 54.
The notches 57, 58 of the opposed, outer
notched sides 55, 56 of the pair of protuberances 46, 47,
each comprises two inwardly tapering, plane sides 60, 61
leading to a flat bottom 62 which accurately locates with
a flattened crest 50 between the top and bottom bevelled
sides 8, 9, 10, 11 of the bifurcated fingers 4, 5, 6, 7
on the connector interface 1.
The protuberances 46, 47 preferably have
truncated ends 63, 64 to ensure mating in the previously
described modes (i) and (ii).
In operation, two of the anvils 29 are mounted
facing one another on the ends of a robotic arm for
movement towards and away from one another. Figure 3
shows a variant 65 of the anvil 31 formed with a base 66
for connection to a robotic arm. In this variant 65 the
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truncated ends 63, 64 are not present. Extensions 69 to the
body 2 protect the anvil engagement surfaces 60, 61 at the
top corner of each protuberance.
When, for example, the alternate micro-interface 54
(Figures 4 to 6) is to be gripped between the anvils 29, the
anvils 29 are moved towards one another with the corner 53 of
the micro-interface 54 roughly aligned between the inwardly
chamfered sides 51, 52 on the micro-interface 54 defining the
waist portion 59. Within its range of action, the respective
chamfered surfaces then rotatably align the sides 45, 49 of
the central recess 48 of the anvil 29 until the top and
bottom chamfers 67, 68 of the inner sides 51, 52 of the
micro-interface 54 are brought into vertical alignment with
the chamfered portion of the sides 45, 49 of the central
recess 48 in the anvil 29. With the protuberances 46,
47 and the micro-interface 54 mated in this manner, the
micro-interface 54 can then be firmly gripped between the
anvils 29.
When, for example, the connector interface 1
(Figure 1) is to be gripped between the anvils 29, the anvils
29 are moved towards one another with protrusions 4
and 5 or with protrusions 6 and 7 of the connector
interface 1 roughly aligned between the protuberances 46 and
47 of each anvil 29. This movement causes the protuberances
46, 47 to enter between the protrusions 4, 5, 6, 7 so
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WO 95/05975 PCT/CA94/00450
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that the outer, notched sides 55, 56 mate with the
outwardly chamfered protrusions 4, 5, 6, 7. This mating
rotatably aligns the outer, notched sides 57, 58 with the
protrusions 4, 5, 6, 7, while, at the same time, causing
vertical alignment between the anvils 29 and the
connector interface 1. With the connector interface 1
held in this manner, it can be firmly gripped between the
anvils 29.
Thus, by providing the anvil 29 with both inner
chamfered walls 45, 49 and outer chamfered, notched
protrusions 46, 47, then the protrusions 46, 47 of anvil
29 can mate with both types of interfaces 1, 54.
Conclusion
The foregoing has constituted a description of
specific embodiments showing how the invention may be
applied and put into use. These embodiments are only
exemplary. The invention in its broadest, and more
specific aspects, is further described and defined in the
claims which now follow.
These claims, and the language used therein,
are to be understood in terms of the variants of the
invention which have been described. They are not to be
restricted to such variants, but are to be read as
covering the full scope of the invention as is implicit
WO 95/0597 PCT/CA94/00450
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within the invention and the disclosure that has been
provided herein.
