Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
wog6/08347 ~ q ~ ~ ~ 8 4 PCT~NZ9SJ00085
ROBOTIC ARM ASSEMBLY
Bac}~4 ~ o~.d of the Invention
The present invention relates to improvements in
and relating to a robotic arm assembly.
The term "robot" is used throughout this
specification in respect of any type of controllable
manipulator. Robots have assumed a major role in
industl-y- peïfoïmins tasks ranging from the automatic
welding of car bodies to the automatic dressing of
animal carcasses.
In applications within ~ood processing,
pharmaceutical manufacturing, etc, a major consideration
is the ability for the robot to avoid becoming
unhygienic such as by it capturing food product
particles or dust for example and for it to be kept
clean such as by washing. In many food processing
environments such as in abattoirs, the conditions can be
extremely harsh characterised by high humidity, high
temperature water and carcass particles and blood. Any
machinery working in such environments will inevitably
require frequent cleaning in order to maintain a
requisite standard of hygiene.
At the present time robots working in harsh
environments have required specially designed protective
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covers as their designs as such have not facilitated
their being kept clean.
It is thus an object of the present invention to
provide a robotic arm assembly which is able to work in
harsh environments but still be able to be kept clean or
which at least will provide the public with a useful
choice.
Further objects of this invention will become
apparent from the following description.
BRIEF SUMMARY OF THE lNv~NLlON
According to one aspect of the present invention
there is provided a robotic arm assembly comprising:
(a) at least one substantially smooth surfaced arm
having manipulating means at least at one free end
thereof;
(b) an enclosed or enclosable support assembly
connected with said arm enabling said arm to pivot
relative thereto;
(c) lineal and rotational drive means being provided
for said arm and said support assembly so as to
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provide a required number of degrees of freedom of
movement;
whereby said support assembly and said arm combine to
form a substantially enclosed construction presenting
substantially readily cleanable external surfaces.
According to a further aspect of the present
ir.ventior, there is provided a robotic ar~ asse~iy as
defined immediately above wherein said support means
includes an inner enclosed plate assembly adapted to
accommodate thereon said rotational and lineal drive
means.
Further aspects of this invention which should be
considered in all its novel aspects will become apparent
from the following description given by way of example
of possible embodiments thereof and in which reference
is made to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fiqure 1 shows a rear, diagrammatic view, of a robotic
arm assembly according to one possible
embodiment of the invention;
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Fiqure 2 shows a front view of the assembly of Figure
l;
Fiqure 3 shows very diagrammatically a left side view
of the assembly of Figures 1 and 2;
Fiqure 4 shows very diagrammatically a right side view
of the assembly of the preceding Figures;
Fiqure 5 shows partial and cross sectional view of the
assembly according to one possible embodiment
of the invention but with the telescopic arm
omitted;
Fiqure 6 shows the support plate assembly for use in a
preferred embodiment of the invention;
Flqure 7 shows diagrammatically a cross sectional view
through the telescopic arm according to one
possible embodiment of the invention.
BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS
As mentioned above, harsh environments involving
temperature, water or other liquids including blood,
humidity, dirt, air borne particles of food or processed
W~96/08347 ~ 9 8 4 PCT~ ~5S00085
debris make it difficult for machinery such as robots to
be kept clean and working. In food processing
environments the need to maintain hygiene is of course
- paramount.
The present invention has therefore sought to
achieve a robotic arm assembly which is suited to
working in a harsh environment but which can be readily
cleaned such as by washing down with high pressure hoses
with water at high temperatures. Referring to Figures 1
to 4 particularly, the robotic arm assembly is
referenced generally by arrow 1 and is shown comprising
a telescopic arm 2 accommodated for pivotal movement in
a direction indicated by arrows A within housing 3.
Only one arm is shown but a plurality of arms 2 is
envisaged. The housing 3 is shown provided, front and
rear, with an arcuate shell housing 4 to accommodate the
pivoting movement of the arm 2. In the Figures, the
front end 5 of the arm 2 is shown in its raised position
within the front shell 4 in the housing 3 but as
required, the arm 2 can be pivoted so as to lower the
front end 5 so that the rear end 7 (see Figure 1) then
moves towards accommodation in the rear shell 4. The
front end 5 of the arm 2 will suitably include, or be
attachable to, the appropriate tooling such as a
cutting, welding or gripping tools or the like with the
W096/08347 PCT~Z9S/00085
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capability of rotating the tool preferably through 360~
in clockwise or anti clockwise directions as indicated
by the arrows B. In the drawings the tool is shown by
way of example as a gripping means 32.. The arm 2 may
suitably be able to pivot about one of the downwardly
depending legs 8 of housing 3 about a suitable pivot
point 6 indicated in profile very diagrammatically in
Figure 2. A housing 9 will suitably accommodate a motor
for ccntrolling the pivoting of the arm 2 and to also
provide a drive for one or more of the rotational or
lineal movements required of the assembly 1.
The assembly 1 may suitably comprise a polar
configuration mountable on a horizontal linear axis and,
depending on its required application, in one embodiment
providing for example a total of four degrees of freedom
of movement (DOF) which in the illustrated embodiment
may be identified as follows:
Axis movements:
Axis Type Range
1. Main Travel Linear 60Omm
2. Main Arm Revolute goo
3. (Telescopic arm) Linear 300mm
4. (Wrist) Revolute 360~
W096/08347 ~ 9 8 4 PCT~ ~5~00085
The number and disposition of the above axes and
the ranges of motion are of course by way of example
only and will depend on a particular application for
which the robotic arm assembly is required.
Alternative mixtures of revolute and linear axes
are of course possible forming part of the present
invention.
To accommodate the lineal movement of the support
assembly 3 with the arm 2 a concertina housing lO is
shown provided on both sides of the housing 3 which is
then able to expand or contract in accommodating the
linear movement. The housings 10 are shown closed off
by respective plate members 11.
The housing 3, plates 11, telescopic arm 2 and
housings 9 and 10 thus combine to provide a very simple
design which presents a minimal number of surfaces
required to be cleaned and those that are present can be
readily washed down such as with a high pressure hose.
To further facilitate cleaning stainless steel and/or
polished aluminium and/or plastics, may be used for any
exposed surfaces. In a preferred embodiment of the
invention the telescopic arm will preferably comprise a
pair of co-axial stainless steel tubes providing a
W096/08347 ~ 8 ~ PCT~S/0008S
stepped portion 12 (see Figure 2). The concertina
structures 10 may suitably be of some plastic material
which provides both a flexible and a washable surface.
In Figure 5, a part cross sectional view of the
assembly 1 illustrates the drive motor 20 positioned
within the housing 9 and mounted to the side of a plate
18 which is shown in greater detail in Figure 6. The
plate 18 includes provision at 19 For a suitable gear
box such as an harmonic drive gear box connectable to
the drive motor through a suitable cantilevered
arrangement. A drive wheel 20 is shown providing a
drive through a suitable belt to a recirculating ball
screw or the like 21 engageable with a fixed threaded
shaft 22 so as to provide for the lineal motion of the
assembly 1.
A pair of parallel linear bearings 23 are shown
engaging with a horizontal support member 24 which will
provide the required support for the assembly external
thereto as it traverses horizontally.
The plate 18 thus provides a main vertical support
for the assembly 1 and the supporting link of the arm 2
to the horizontal carriage way 24. The plate 18, which
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may be machined from solid metal such as aluminium is
also supporting the linear axis motor and the lead screw
actuation system.
The overall support for the assembly 1, which may
in any particular embodiment weigh in the region of
lOOkg, can be by means for example of a suspension from
a cantilever from a chain superstructure; such an
arrangement avoids any suppcrt from below which could
affect the ability o~ cleaning beneath the robotic arm
assembly 1.
It is seen therefore that the plate assembly 18 is
able to achieve a combination of functions in providing
the support for the drive and drive connections to the
assembly 1 thus enabling the single cover assembly 3 to
provide the simple yet effective pivotal support for the
arm 2.
In Figure 7 the arm 2 is shown with its front
manipulator end 5 at the front end of an inner tube 2A
telescopically slideable within an outer tube 2B along a
shaft 25. The telescopic movement can be controlled by
means of a screw/threaded rod arrangement, piston and
cylinder hydraulic arrangement, or the like.
W096/08347 ~ ~ g ~ ~ 8 4 PCT~Z95~-Y~
-- 10
In the preferred embodiment as shown a beariny
assembly may comprise a linear bearing 31 at one end and
a nickel impregnated Teflon (Registered Trade Mark)
bearing 30 or the like at the other end. This may avoid
the need for exact tolerances in the manufacture of the
arm 2 and hence reduce costs.
A further aspect of one embodiment of the present
invention relates to the mar.u acture o~ the tubes 2A,
2B. Their mass and stiffness are very important but
normal construction can be difficult. Accordingly
software routines may be written for a CAD package which
automatically produces the flat developments of the
intersection of the tubes and these drawings are
exported as DXF files. The DXF files may then be read
by a laser cutting machine or the like to accurately cut
the shapes from sheet material. The shapes may then be
folded or rolled and fitted into special jigs where they
are welded together. The welded joints can then be
ground and polished.
It is thus seen that the present invention provides
a robotic arm assembly which has a substantially compact
design resulting in a minimum of exposed surfaces but
which surfaces can substantially be provided so as to be
readily washable. The assembly is therefore adapted for
WO 96/08347 PCII~Z95,'~- D~C
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use in environments where hygiene considerations are
important. The compact design also enables a relatively
small number o~ joints to be required between the
various components having external surfaces and where
any exposed joints are present these may be readily
sealed so as to prevent the ingress of water or other
material or where such ingress may be unavoidable the
compact design can ensure that this will not adversely
affect the operation o~ the asser~ly.
Where in the foregoing description, reference
has been made to specific components or integers of the
invention having known equivalents, then such
equivalents are herein incorporated as if individually
set forth.
Although this invention has been described by way
of example and with reference to possible embodiments
thereof, it is to be understood that modifications or
improvements may be made thereto without departing from
the scope or spirit of the invention as defined in the
appended claims.
