Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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LOAD TENSION ALERT DEVICE
FIELD OF THE INVENTION
The present invention concerns a load tension alert device, more particularly
to
an alert device for use with a tensioned load on a vehicle load bed.
BACKGROUND OF THE INVENTION
Road accidents involving trucks carrying heavy loads are commonplace.
Oftentimes, the accidents are caused by loads shifting on the load bed, which
can ultimately cause instability of the truck during turning or when traveling
at
high speed. The loads are typically secured to the truck's load bed by a
number
of securing straps. The securing straps are normally lashed over the load and
connected to both sides of the load bed using hooks or some other suitable
connecting means. While this type of load securing is satisfactory, it has
some
significant drawbacks. For example, loads have a tendency to shift during
transport and the tension in the securing straps can decrease, which results
in
unstable loads that may dislodge and fall off the load bed causing injury and
damage to property. Moreover, the vehicle driver is often unaware of this
decrease in strap tension and often has to manually check the integrity of the
load, especially on long journeys. This checking increases the delay in
delivery
of the load and may increase the cost of transporting the load.
Thus there is a need for an alert system that can remotely check the tension
in
the securing straps and relay an alert signal to the driver if there are any
differences in tension.
SUMMARY OF THE INVENTION
The invention reduces the difficulties and disadvantages of the prior art by
providing a novel tension alert device that can be incorporated into existing
securing systems and which provides an inexpensive method of monitoring
tension in a load secured by tensioned straps. Advantageously, the device
uses a simple contacter mechanism that includes two contacters, one movable
towards the other to generate an electrical circuit; such as when tension in
the
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straps decreases due to a shifting load, and which sends a signal to the
driver's
cab alerting him to this fact. To achieve this, a novel connector is provided
which relays to the cab differences in tensions. In addition, multiple devices
can
be used to measure the overall tension in the load securing straps and provide
to the driver a continual flow of information. Armed with this information,
the
driver can signal ahead for help or can stop the truck and selectively
readjust
the tension. Furthermore, the present device allows for wireless communication
between the trailer and the cab, thereby eliminating the need of a wire bundle
there between that would be cumbersome.
In accordance with a first aspect of the present invention, there is provided
a
tension alert device for use with a load secured to a vehicle load bed, said
device having a first elongate securing member having a first vehicle load bed
connector and a first attachment link, said device comprising; a connector
sleeve having an axial bore and a sleeve end portion connected to said first
attachment fink; a first contacter connected to an inner end portion of said
connector sleeve and facing into said axial bore; a second contacter mounted
to
slide in said axial bore along a restricted path of travel and having a second
vehicle load bed connector connected to said vehicle load bed, said second
contacter facing said first contacter and being urged away therefrom when said
first elongate securing member has a first tension threshold value; said
second
contacter being biased towards said first contacter when said first elongate
member attains a second tension threshold value, said first contacter having
an
electrical signal generator for producing an electrical signal, said
electrical
signal generator being activated when said second contacter is biased
thereagainst.
Typically; the connector sleeve includes a connector sleeve sidewall and a
central column connected to an end sidewall and continuous therewith, said
column having an axial column bore. The central column includes a stop end
portion directed into said axial bore.
Typically; the first contacter includes a push button activatable by said
second
contacter when said second threshold tension value is attained. The push
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button is electrically connectable to an emitter when said second threshold
tension value is attained. The emitter is connected to said inner end portion
of
said sleeve. The emitter includes an emitter casing surrounding said emitter,
said emitter casing connected to said sleeve sidewall.
Typically, the second contacter includes a plunger having a plunger head for
contacting said stop end portion of said column and a plunger shaft, said
plunger shaft being sized to slide in said axial column bore.
Typically, a biasing means is connected to said plunger head and to said base
sidewall.
Typically, a signal receiver is located in a cab of said vehicle. The signal
receiver is calibrated to alert an operator to said second tension threshold.
Other objects and advantages of the present invention will become apparent
from a careful reading of the detailed description provided herein, with
appropriate reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Further aspects and advantages of the present invention will become better
understood with reference to the description in association with the following
Figures, wherein:
Figure 1 is a simplified perspective view of a loaded vehicle including a
number
of tension alert devices;
Figure 2 is a perspective exploded view of a tension alert device in
accordance
with an embodiment of the present invention;
Figure 3 is a cross section view of the tension alert device in a signal
generating configuration under a second tension threshold value; and
Figure 4 is a cross section view of the tension alert device in a fully
tensioned
configuration under a first tension threshold value.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figures 1 and 2, there is shown generally at 10 a tensioning
alert
device of the present invention connected to an elongated securing strap 12,
belt or the like, lashed over a load 14 on a load bed 16 of a truck 18 having
a
cab 20. Broadly speaking the device 10 includes an attachment link piece 22, a
first load bed connector hook 24, a connector sleeve 26, a plunger 28 and a
second load bed connector 30; or strap connector.
The strap 12 is typically constructed of a resilient material which, when it
is
lashed over the load 14 and attached to the load bed 16 using the connector
hook 24; the strap 12 has a first tension threshold value. The first hook 24
is
typically connected to the side of a load bed frame 32. As is typical for most
loads, many straps 12 are used for maximum securing efficiency and, as will be
clear to one skilled in the art, corresponding numbers of tensioning alert
devices
10 may be used with the straps 12.
Referring now to Figures 2, 3 and 4, the connector sleeve 26 includes an axial
bore 34 and a sleeve end portion 36, which is connected to the first
attachment
link 22. Typically, the connector sleeve 26 includes first and second sleeve
portions 27, 29, which are threaded to be screwed into each other to aid
replacement of a conventional battery 60. The connector sleeve 26 includes an
inner end portion 38 and a first contacter 40 connected thereto. The first
contacter 40 is connected so that it faces into the axial bore 34. The second
sleeve portion 29 has a connector sleeve sidewall 42 and a central column 44
connected to an end sidewall 46. The end sidewall 46 and the central column
44 are continuous with each other, the central column 44 projecting into the
axial bore 34. The central column 44 is typically positioned so that it is
generally axially aligned with the first contacter 40. The central column 44
includes an axial column bore 48, which is sized to accommodate the plunger
28 and to allow the plunger 28 to slide along a path of travel in the axial
column
bore 48. The central calumn 44 includes a stop end portion 35 directed into
the
axial bore 34.
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The plunger 28 includes a second contacter 50 connected to a plunger guide
head 52, which is connected to the end of a plunger shaft 54. The plunger
shaft
54 is connected to the second load bed connector 30, which is connected to the
securing strap 12. The plunger guide head 52 both ensures an axial
5 displacement of the plunger 28 relative to the second sleeve portion 29 by
riadially fitting into the axial bore 34, and restricts the movement of the
plunger
along the path of travel by abuttingly engaging the stop end portion 35.
The second contacter 50 faces into the axial bore 34 and is generally axially
aligned with the first contacter 40. When the securing strap 12 is at the
first
tension threshold value, the first tension value is sufficient to urge the
plunger
28, and therefore the second contacter 50, away from the first contacter 40,
as
shown in Figure 4. A plunger biasing tension spring 56 is connected to the
underside of the plunger guide head 52 and to the end sidewall 46. When the
first tension value in the securing strap 12 decreases to below a pre-
determined
limit dictated by the plunger biasing spring 56, such as when the load 14
shifts
on the load bed 16 or when one of the number of straps 12 breaks, the strap 12
attains a second threshold tension value. The second tension threshold value
causes the plunger biasing spring 56 to bias the plunger 28 and therefore the
second contacter 50 towards the first contacter 40 and generates an electrical
signal, as described below.
A push button 61 is mounted in the connector sleeve 26 and is moveable when
the second contacter 50 is biased against it at the second threshold tension
value. The push button 61 includes an electrical signal generator 59 and a
push
button biasing spring 63. The signal generator 59 includes a first electrical
connector 67 extending generally radially away from the push button 61 and a
second electrical connector 69 extending generally radially towards the first
electrical connector 67. As shown in Figure 3, when the push button 61 is
moved. inwardly by the second contacter 50 against the action of the push
button biasing spring 63, the two electrical connectors 67, 69 electrically
connect and allow a signal emitter 58 to typically send an electromagnetic
(radio
frequency) signal. The signal emitter 58 is connected to the inner end portion
38 of the first sleeve portion 27 and to the electrical contacts 67, 69. The
signal
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emitter 58 is electrically connected to and powered by the battery 60. The
emitter 58 includes an emitter casing 62 which surrounds the emitter 58 and is
in contact therewith and the sleeve sidewall 42.
An end plate 64 is connected to the emitter 58 and to the sleeve sidewall 42
and
serves to center and axially align the first contacter 40 with the second
contacter 50.
As seen in Figure 1, a signal receiver 66 is located in the cab 20 of the
vehicle
18 for wirelessly receiving any signal sent by any tensioning alert device 10.
The signal receiver 66 is calibrated to alert an operatorldriver to a signal
that is
emitted from the respective emitter 58 when its second threshold tension value
is attained.
Although the present load tension alert device has been described with a
certain
degree of particularity it is to be understood that the disclosure has been
made
by way of example only and that the present invention is not limited to the
features of the embodiments described and illustrated herein, but includes al!
variations and modifications within the scope and spirit of the invention as
hereinafter claimed.
