CONVEYOR ROLLER NIP POINT AUTOMATIC PROTECTION DEVICE

DISPOSITIF DE PROTECTION AUTOMATIQUE DE LIGNE DE CONTACT DE TRANSPORTEUR A ROULEAUX

English Abstract

In industrial belted conveying systems, it is common to have a pull chord
extending longitudinally along the conveyor, sometimes one chord on each side
of the
conveyor, said chord being attached to a trip mechanism, or safety switch. A
number of
serious accidents have occurred in the industry due to unprotected nip points
at the return
idlers under these conveyors. Accidents were the result of these pull chords
not being
easily accessible for manual activation of the safety features. In this
invention, a primary
pull chord is placed near the nip point, inserted through guides, and linked
to one or more
secondary longitudinal pull chord(s). The primary pull chord may be sleeved
with a
semi-rigid, pliable rod as additional support between the guides. Further,
this semi-rigid
rod may be encapsulated in a lightweight foamy tube to give it bulkiness. In
the event of
an inadvertent incident, the primary pull chord is entrained into the nip
point, pulling the
secondary longitudinal pull chord which then trips the safety switch,
automatically
disabling the conveyor drive.

Claims

The embodiments of the invention in which an exclusive property or privilege
is
claimed by the inventor are defined as follows:
1. A belted conveyor roller nip point automatic protection device comprising
of
a primary pull chord length; sleeved with a shorter semi-rigid pliable support
rod; the primary pull chord spanning across the width of said conveyor, on
the upstream side near any one of a conveyor belt's roller nip point; each end
of the said primary pull chord is reeved through guides rigidly attached onto
each side of said conveyor, until the ends of the support rod are resting onto
their respective guides; one end of the primary pull chord is rigidly attached
to one side of the conveyor; the other end of the primary pull chord is linked
to a secondary pull chord longitudinal to, and on the opposite side of, the
conveyor, this secondary pull chord in turn being connected to a conveyor-
disabling safety device, for which, if the primary pull chord is inadvertently
entrained into the nip point, it in turn draws on the secondary pull chord
which then trips the safety device and automatically de-energizes the
conveyor drive motor, stopping the belt.
2. A belted conveyor roller nip point automatic protection device comprising
of
a primary pull chord length, sleeved with a shorter semi-rigid pliable support
rod; the primary pull chord spanning across the width of said conveyor, on
the upstream side near any one of a conveyor belt's return idler nip point;
each end of the said primary pull chord is reeved through guides rigidly
attached onto each side of said conveyor until the ends of the support rod are
resting onto their respective guides; each end of the primary pull chord is

linked to a secondary pull chord longitudinal to the conveyor, these
secondary pull chords in turn being connected to a conveyor-disabling safety
device, for which, if the primary pull chord is inadvertently entrained into
the
nip point, it in turn draws on the secondary pull chord which then trips the
safety device and automatically de-energizes the conveyor drive motor,
stopping the belt.
3. A protection device as defined in claim 1, for which the primary chord semi-
rigid pliable support rod is encapsulated with a lightweight foamy tube to
give it bulkiness thereby increasing the surface area, and improve the
likelihood it will get entrained into the nip if an external force displaces
it
from its original position.
4. A protection device as defined in claim 2, for which the primary chord semi-
rigid pliable support rod is encapsulated with a lightweight foamy tube to
give it bulkiness thereby increasing the surface area, and improve the
likelihood it will get entrained into the nip if an external force displaces
it
from its original position.
9

Description

CA 02380585 2002-04-23
DESCRIPTION
This invention relates generally to novel and advantageous improvements to
belted conveyor safety devices. It is common to have a pull chord extending
longitudinally along the side of industrial materials handling conveyors,
sometimes one
chord on each side ofthe conveyor. 'These chords are generally rigidly
attached at one
end, then threaded through the center of eyebolts along the length of the
conveyor, and
are finally fastened at the other end to a trip mechanism, or safety switch.
These devices
are un-affectionately known as 'Dec~a' Maya Switches '. A person pulling an
this chord
activates the switch, which de-energizes the conveyor by opening the
electrical circuit to
the drive motor, thus stopping the conveyor belt.
A number of serious accidents have occurred in the industry which have
resulted
in injury, or worse, due to unprotectEd nip points at the return idlers under
belted
conveying systems. The nip point is the pressure point between the moving
rubber belt
and the r~urn idler roller. It is analogous to the double-roller squeezing
action of the
antiquated wringer-washer. The return idlers are located cross-directionally
to the belt
travel, on the underside, or belly of fhe conveyor.
2a Extensive guarding, or barriers, could be installed to restrict access
underneath
these conveying structures while they are in operation. These barriers
ultimately become
inefficient in terms of safeguarding devices, especially when affectuig
housekeeping in
these areas, because there is a likelihood af-.
~ the barriers are inevitably opened or removed;
the guards are not replaced, or;
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CA 02380585 2002-04-23
1 the guards are simply left open if they are hinged.
Tools (such as brooms, rakes, or shovels) and personal loose clothing can
become entrained into these nip points. Although longitudinal pull chords and
trip
mechanisms are meant to be a protective device as a combination, chances are
if and
while au accident occurs, the casualty does not have the reach, or the thought
process, to
manually activate the tripping mechanism by pulling the longitudinal chords.
Hence,
these mechanisms are also not effective safeguarding devices.
In this invention, a simple, inexpensive, yet efficient device has been
developed
to minimize the risks of injuries with consideration to housekeeping
requirements on the
underside of belted conveyors.
I have found that the inaccessibility to, and the inefficient manual
activation of
the longitudinal pull chord can be easily overcome.
In this invention: a primary pull chard length is sleeved with a shorter semi-
rigid
support rod; this primary pull chord spans in parallel closely upstream of a
conveyor
return idler nip point; each end of the said pull chord is inserted through
guides rigidly
attached onto each side of said conveyor; at least one end of the primary pull
chord is
linked to a secondary pull chord, longitudinal to the conveyor, this secondary
pull chord
in turn is connected to a conveyor-disabling safety device; and the other end
of the
primary pull chord, if not attached ta. another secondary pull chord on the
opposite side of
the conveyor to the first secondary p>xll chord, it is then rigidly attached
onto that
opposite side ofthe conveyor.

CA 02380585 2002-04-23
Additionally, the semi-rigid support rod may be encapsulated in a lightweight
foamy tube to give it bulkiness by..increasing the surface area.
In the event of an incident; the primary pull chord, being close to the
leading
edge of the nip point, is automatically entrained into the nip point. The
primary chord in
turn draws the secondary longitudinal pull chord, which'then trips the safety
switch, thus
effectively de-energizing the conveyor belt.
The added bulkiness of the lightweight foamy tube encapsulating the semi-rigid
support rod improves the likelihood the primary pull chord will get entrained
into the nip
if an external force displaces it from its original position.
Although the intent of this device is to serve as a more efficient means of
activation of the tripping mechanism, it is not meant to act as a barrier. If
an incident
does occur, this device will minimize the extent of the injury. It also serves
as a more
direct and accessible pull chord even if it is not actually entrained, for one
reason or
another, into the nip point.
It is an overall aim of the present invention to provide a conveyor belt nip
point
protection device.
It is also an aspect of this invention to provide a more efficient and
automatic
conveyor-tripping mechanism by providing a direct and accessible pull chord
close to the
nip point.
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CA 02380585 2002-04-23
Yet another advantage of this invention is to afford a semi-rigid mechanism
that
can be reset into place after having been activated:
Still another aim of the presern invention is for a product to be pliable with
minimal r~lacement parts after having gone through the nip point a number of
times.
Finally, one last objective of this invention is to offer a product that can
be easily
and inexpensively manufactured.
Other objects and advantages of the presem invention may present themselves
from the following description when considered with the accompanying drawings,
in
which:
Figure 1 is a partial perspective view of one embodiment, and;
Figure 2 is a more detailed sectional elevation view of another embodiment.
Referring now in more detail and by reference characters to the drawings which
designate identical or corresponding practical embodiments of the invention
throughout
the several views, Fig. l illustrates aprimary pull chord 10; which spans
across a
conveyor 20 and parallel to a return idler 21 for the conveyor belt 22, said
primary chord
spotted in close proximity upstream to the nip point 23 b~ween the conveyor
belt motion
24 and the return idler rotation 25.
4

CA 02380585 2002-04-23
The free-standing primary pull chord 10 would eventually droop downwards
because of thermal variations, or age. As a preventative measure, the primary
pull chord
is sleeved with a semi-rigid, yet pliable support rod 11.
Each end of the primary pull chord 10 is then reeved through a guide 30
rigidly
attached to the side of the conveyor 20, until each end of the support rod 11
rests onto
their respective guides 30:
Likewise; each end of the primary pull chord 10 is terminated by a hoop 40
10 around a thimble 41, held in place with one or more cable clips 42, as
viewed in Fig. 2.
Still as depicted in Fig: 2; one end of the primary pull chord 10 is rigidly
attached
to one side of the conveyor by means of fasteners 43, and the her ~d of the
primary
pull chord 10 has a secondary pull chord 50 threaded through the eye of the
hoop 40.
Each end of the secondary pull chord 50 is in turn terminated by a similar
hoop
40, with one end rigidly fastened to one end of the conveyor 20.
Referring back to Fig. 1, the secondary pull chord 50 runs longitudinally
along
the conveyor 20, laced through strategically located eye-bolts 52. The other
end of the
secondary pull chord 50 is fastened to a conveyor-disabling safety device 51
at the other
end of the conveyor 20.
Ahernatively, and symmetrically as visible in Fig. l, the hoop 40 at each end
of
the primary pull chord 10 could each' be threaded with their own secondary
pull chord 50

CA 02380585 2002-04-23
running longitudinally along each side of the conveyor 20, said individual
secondary pull
chords 50 fastened at one end of the conveyor 20, and the other end of these
secondary
pull chords 50 fastened to dual conveyor-disabling devices 51, one on each
side at the
other end of the conveyor 20.
Additionally, the semi-rigid rod ll may be encapsulated with a lightweight
foamy tube 12 in order to give extra bulkiness to the primary pull chord 10.
As a sequence: In the event of an incident, the primary pull chord 10 is
entrained
into the nip point 23 between the conveyor belt motion 24 and the return idler
rotation 25,
pulling the said primary pull chord's support rod I1 off or out of the guides
30. As the
primary pull chord 10 is being drawn through the guides 30, it tugs on the
secondary pull
chord 50, which then trips the conveyor-disabling device 51, automatically.
Thus it has been described and illustrated a novel and unique belted conveyor
roller nip point protection device which fulfills all of the associated
objectives and
advantages sought thereof
It must be understood, although it is not shown or described, that other
app~dages may be incorporated to this ernbodim~t with no deviations from the
stated
embodiment's intended purposes, these appurtenances serving either useful or
cosmetic
means:
a) The guides may be adapted to roller screened- or meshed-guards;
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CA 02380585 2002-04-23
b) The guides or support rod may be adapted to roller drop-off guards or
frames;
c) The same purpose may be achieved if the embodiment is placed on conveyor
rollers other than the return idlers.
It should also be understood that any changes, modifications variations,
substitutions, or other applications or uses will become apparent to those
skilled in the art
upon consideration of this disclosure and its associated drawings.
It should further be understood that all changes, modifications, variations,
substitutions, or any other applications or uses which do not depart from the
scope and
spirit of the invention are considered to be covered by th.e invention which
is limited only
bythe accompanying claims.
7

Representative Drawing