Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
"EAR TAG ASSEMBLY"
FIELD OF THE INVENTION
This invention relates to an animal identification device and in
particular to an ear tag assembly for attachment to an animal. The invention
also relates to an improved attachment means for attaching the animal
identification device to the ear of an animal.
BACKGROUND TO THE INVENTION
Modern farming techniques require careful stock control
including the ability to recognise individual animals. This has been achieved
by tagging animals in identifiable ways. Known tagging methods include ear
tags, ear clips and brands (normally applied to the rump). Although these
methods provide identification they do not generally identify individual
animals, nor do they permit rapid or automatic identification and remote
recording.
Electronic identification devices have been developed to
provide rapid and automatic identification and remote recording. These
devices fall into two broad classes. Devices which are carried within the
animal (either sub-cutaneously or internally) and those which are attached
to the animal. Of the latter variety, those attached to the ear of animal are
probably most prevalent.
An ear tag may serve two purposes. It may provide a visible
indication by virtue of a distinctive colouring or numbering, and it may
provide
electronic identification by virtue of a transponder housed in the ear tag. In
our co-pending application, Australian Patent Application Number 36640/95,
an attachable transponder housing is disclosed which allows universal
attachment of a transponder housing to known ear tag assemblies. Although
the attachable transponder housing is useful with conventional numbered ear
tags, it is preferable that a suitable ear tag housing and transponder be
fitted
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in the first instance.
A number of ear tag assemblies housing transponders are
known in the prior art but each suffers from one or more shortcomings. One
such example is disclosed in International Application Number
PCT/SE91/00476 in the name of Alfa-Laval Agricultural International AB.
This application discloses an animal identification device in which a
transponder is moulded in a cavity in a hard capsule which in turn is moulded
in a soft carrier material. The device is attached to the ear of an animal by
a pin which passes through the ear and engages a boss formed in the carrier
material.
A major failure mode of transponders is shock due to impact
which results in damage to the internal components of the transponder,
particularly the ferrite rod. The soft material of the Alfa-Laval device does
not
prevent damage to the hard casing or shock damage to the transponder.
Furthermore, damage to the soft material can result in detachment of the
device from the animal. Both situations result in a failure in the purpose of
the device.
An ear tag must be able to withstand considerable pressure
resulting from
~ an hydraulic head bail applying several hundred pounds
pressure;
~ other animals chewing the ear tag;
~ other animals standing on the ear tag;
~ the ear tag being knocked against or by hard objects.
Another prior art ear tag assembly is described in International
Patent Application Number PCT/NZ93/00037 in the name of Allflex New
Zealand Limited. The Allflex ear tag has the transponder in a hard casing
which is integrally moulded with a carrier which is preferably the female
component of a two part ear tag. As with the Alfa-Laval device, the Allflex
device is subject to damage to the transponder as it is insufficiently
protected
in the polyurethane carrier. There is no shock protection provided and thus
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the electronics of the transponder may be damaged even though the
external damage to the ear tag appears minimal.
Similar failure modes due to damage exist for the device
described in United States Patent Number 4718697 in the name of Allflex
International Limited. The device disclosed in this patent has the transponder
moulded in a hard bubble in the middle of rectangular tag. The tag hangs
from the ear of an animal such that the transponder is in a position that is
particularly susceptible to impact or pressure. The mechanical arrangement
of this Allflex device does not provide the protection necessary to ensure
long-term, damage-free operation of the transponder contained therein.
Another problem common to prior art ear tags is the tendency
for ear injury to occur due to the tag or pin becoming caught on wire fences
and the like. Most pins for ear tag attachment comprise a round button that
seats against the rear of the ear. A pin projects through the ear from the
button and engages with the tag. If the animal grazes near a fence (which is
common) the wire of the fence can catch on either the tag or the button. As
the animal pulls away the ear tag or pin may be damaged or the ear of the
animal may be torn. Infection can then occur resulting in loss of all or part
of
the animals ear and probable loss of the ear tag and transponder.
Furthermore, the infection causes the ear to be itchy so the animal rubs the
ear further increasing the likelihood of the tag being lost or damaged.
The inventor is also aware that cases of infection behind ear
tags are relatively common. This can occur soon after the ear tag is first
applied and generally occurs under the button behind the ear. The inventor
speculates that this is most likely due to restricted air flow around the
button
preventing healing of the wound caused when the ear tag is positioned.
A contributing factor to a number of the above identified
problems is the size and location of the known ear tags. It would be
advantageous to provide a smaller ear tag assembly which is located
primarily within the ear.
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OBJECT OF THE INVENTION
It is an object of the present invention to provide an ear tag
assembly overcoming one or more of the identified problems in the known
prior art.
Further objects will be evident from the following description.
DISCLOSURE OF THE INVENTION
In one form, although it need not be the only or indeed the
broadest form, the invention resides in an ear tag assembly for attachment
to the ear of an animal comprising
a body having a chamber therein for housing a transponder,
said transponder being insertable into the chamber through at least one
opening in the chamber;
a plug for sealing said opening; and
a pin insertable through the ear of the animal to engage the
body, said pin and body acting cooperatively to retain the ear tag assembly
on the ear of the animal;
wherein said body is formed from hard plastics material and
said body comprises a substantial cylindrical portion having a ridge
projecting therefrom.
The ear tag assembly preferably further comprises cushioning
means for surrounding the transponder in the chamber.
In preference the body further comprises a plate-like portion
extending from the cylindrical portion, said plate like portion including an
attachment aperture adapted to engage the pin with holding effect. The
plate-like portion may further include a reinforcing rib.
The body suitably has a long axis less than 75mm long and
preferably less than 45mm long. The diameter of the cylindrical portion is
suitably about 10mm.
The ear tag assembly is preferably formed from ultraviolet
radiation resistant plastics material. The plastics material is suitably
nylon.
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The material is preferably black to minimise absorption of ultraviolet
radiation.
The ear tag assembly suitably includes a pressure equalising
passage that allows pressure equalisation during insertion of the plug into
5 the chamber. In one form the pressure equalising passage extends from one
end of the plug to just short of the other end of the plug. Alternatively the
passage may extend for the length of the plug.
There may be provided a circumferential ridge on the plug for
engaging in a circumferential trough in the chamber for snap-lock
engagement of the plug in the opening.
The pin preferably comprises a backing component and a shaft
extending therefrom. The shaft may suitably be shaped at an end distal from
the backing component to be engaged by the attachment aperture of the
body with holding effect. The shaft of the pin preferably has a diameter less
than the diameter of the aperture thereby allowing free rotation of the body
on the shaft of the pin.
The distal end is preferably shaped to penetrate the ear of the
animal to be tagged. The shape may be a point and the point may be
suitably hardened.
The backing component may be flat but is preferably curved
towards the ear so as to be concave with respect to the shaft. The backing
component is suitably longer than it is wide with the width being
approximately equivalent to that of the shaft in the vicinity of the backing
component.
The backing component is preferably domed such that a region
in the vicinity of the shaft is thicker than the perimeter.
The pin is suitably formed from the same hard plastics material
as the body.
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BRIEF DETAILS OF THE DRAWINGS
To assist in understanding the invention preferred
embodiments will now be described with reference to the following figures in
which
FIG 1 is an exploded view of an ear tag assembly;
FIG 2 is a sketch of the body of the ear tag assembly of FIG
1 from a different angle;
FIG 3 is an end view of the body of FIG 1;
FIG 4 is a sketch of the pin of FIG 1;
FIG 5 is a side view of the pin of FIG 4;
FIG f~ is a sketch of an alternate form of the plug of FIG 1;
FIG 7 is a sketch of a transponder suitable for use in the ear
tag assembly of FIG 1;
FIG 8 is a sketch of the ear tag assembly of FIG 1 applied to
the ear of an animal; and
FIG 9 is an assembled view of an ear tag assembly.
DETAILED DESCRIPTION OF THE DRAWINGS
In the drawings, like reference numerals refer to like parts.
Referring to FIG 1 and FIG 9, there is shown an ear tag
assembly comprising a body 1, pin 2 and plug 3. The body 1 comprises a
generally cylindrical portion 4 and plate-like portion 5 extending therefrom.
The cylindrical portion 4 has a ridge 6 projecting substantially along its
length. The ridge 6 is integrally formed with the cylindrical portion 4.
As seen most clearly in FIG 3 the cylindrical portion 4 is
substantially circular in cross-section except for the substantially
triangular
ridge 6. The ridge 6 is rounded at its apex, thereby avoiding any problems
associated with sharp edges and to provide resistance against crushing.
The plate-like portion 5 includes an aperture 7 for receiving the
end 8 of the pin 2, as described in detail below. A rib 9 reinforces the plate-
like portion 5. To minimise the possibility of snagging the rib 9 flows into
the
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plate-like portion 5 in the vicinity of top region 10 without any edge or
step.
This minimises the opportunity for the tag to be snagged or caught as can
occur with prior art tags.
A chamber 11 is formed in the body 1 for receiving a
transponder (not shown). The chamber 11 is closed by inserting the plug 3
into the open end thereof. Because the chamber is closed the insertion of the
plug would be prevented by compression of the air in the chamber. To
overcome this problem the plug 3 includes a pressure equalising passage
12 that allows air to escape from the chamber while the plug is being
inserted. The outer end of the pressure equalising passage is closed so that
the final insertion of the plug seals the chamber.
In an alternate embodiment the pressure equalising passage
may extend for the length of the plug 3, as depicted in FIG 6.
To assist in retaining the plug 3 in the chamber 11 a
circumferentiai ridge 13 is formed near the outer end of the plug. A
corresponding circumferential trough 14 is formed in the inside surface of the
chamber 11. The plug 3 is pushed into the chamber 11 until a snap-locking
is achieved by the location of the ridge 13 in the trough 14. It will be
appreciated that the circumferential ridge and trough can be replaced by
other similar mechanisms such as one or more matching bumps and
indentations.
The forming of a chamber closed by a plug allows the
transponder to be inserted after manufacture of the ear tag. It also allows
appropriate shock absorbing material to be inserted around the transponder.
This cannot be adequately achieved if the transponder is moulded into the
ear tag during the manufacturing process.
The pin 2 is shown most clearly in FIG 4. The pin comprises a
backing component 15 and a shaft 16 extending therefrom. The backing
component 15 is curved towards the shaft 16 and slightly domed such that
it is thicker in the vicinity of the shaft 16 than at the perimeter. The
doming
assists in deflecting snags from the backing component. The curvature of the
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backing component closely matches the curvature of the ear of the animal
thereby minimising the gap between the backing component and the ear and
minimise the possibility of the backing component becoming caught or
snagged. Similarly, the chance of the ear tag being snagged is also reduced.
In one form the curved backing component may be resilient so
that it deflects when the ear tag assembly is attached to the ear of an
animal. Pressure is applied to the back of the ear by the backing component
thereby pulling the backing component firmly against the ear.
The shaft 1 C is shaped at an end 17 distal from the backing
component 15 to be engaged with holding effect by the aperture 7 in the
plate-like portion 5. The distal end 17 has a small step or ridge 18 which can
be resiliently deformed under pressure to pass through the aperture 7 but
is virtually impossible to withdraw. In fact, the pin must normally be cut for
the tag to be removed from the animal.
The diameter of the shaft 16 is slightly less than the diameter
of the aperture 7 so that the body 1 is able to rotate freely about the shaft
16.
This further minimises the possibility of the tag being snagged since the tag
will rotate and become unsnagged.
The pin 2 is self-piercing with the distal end 17 shaped to
penetrate the ear of the animal to be tagged. The pin is formed from
sufficiently hard material for the tip 19 to be able to penetrate the ear. If
required, the tip 19 may be hardened further with a metal cap to assist in
piercing the ear.
A conventional applicator punch (not shown) is used to attach
the ear tag assembly to the animal. Known applicator punches use a stud
that extends into an aperture in the back of the pin 2 to hold the pin. To
facilitate the use of known applicator punches the shaft 16 of the pin 2 has
a hole 20 provided therein for access of the stud from the rear. The hole 20
extends to the ridge 18 thus minimising the likelihood of the shaft 16 bending
during application.
The backing component 15 is elongate rather than round as in
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prior art pins. An elongate backing component facilitates the flow of air
behind the ear and minimises the opportunity for snagging. If the backing
component does engage a snag it can easily rotate and unsnag. As
described above, the diameter of the shaft 16 is smaller than the aperture 7
in the plate-like portion 5 of the body 1 to facilitate easy rotation. The
narrow
width of the backing component 15 also facilitates air flow around the ear of
the animal where it is penetrated by the shaft of the pin. The inventors are
aware that infection around the pin of known ear tag assemblies is prevalent.
Allowing circulation of air reduces the incidence of infection.
The body is made from hard plastics material to provide
strength and to protect the transponder. The ridge 6 provides further strength
and protection against pressure. As mentioned above, the body 1 must
withstand considerable pressure in normal circumstances and very high
pressure in unusual circumstances. Normal livestock conditions are harsh
and cause failure of known transponders.
To further protect the transponder 21 it is located in a
surrounding cushioning sheath 22, as shown in FIG 7, prior to loading the
transponder 21 into the chamber 11. The cushioning sheath 21 provides
shock protection for the transponder. Although the cushioning sheath 21 is
shown as an extruded member it may also be in the form of a grease or
expanding foam. It will be appreciated that the transponder is protected
against damage by the combination of the hard body of the ear tag and the
cushioning of the transponder within the body. This arrangement has been
reached by the inventors after considerable experimentation and trial.
The plastic from which the ear tag assembly is formed is UV
resistant to increase its lifetime. The inventors have found that one failure
mode of known ear tag assemblies is associated with the body becoming
brittle due to hardening of the plastic from exposure to ultraviolet
radiation.
Other failure modes are due to the tag being made from soft plastic which
offers too much flexibility, or hard plastic too close to the transponder
which
transmits shocks.
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The location of the ear tag assembly on the animal means that
the tag is exposed to high dosages of UV radiation. The effect of UV
radiation is minimised by using UV resistant material. The inventors have
found that nylon is a suitable material although other materials, such as
5 polycarbonates, may also be suitable. The effect of UV can be further
ameliorated by using black material.
The pin may suitably be formed from the same hard, UV
resistant material as the body.
The location of the ear tag assembly on the ear 23 of an animal
10 is shown in FIG 8. It will be appreciated that the size and shape of the
body
1 of the ear tag assembly is particularly advantagous for minimising the
opportunity for the ear tag assembly to become snagged. Furthermore, the
shape of the pin 2 also minimises the opportunity for snagging. The inventors
have found that the body only needs to be moderately larger than the
transponder it houses. A body having a long axis less than 75mm is easily
achievable. The inventors have found that the preferred size is a body
having a long axis less than 45mm long. The diameter of the body is suitably
around 10mm.
Throughout the specification the aim has been to describe the
preferred embodiments of the invention without limiting the invention to any
one embodiment or specific collection of features.
