Note: Descriptions are shown in the official language in which they were submitted.
CA 02882313 2015-02-19
LOCKING MECHANISM FOR RELEASABLY SECURING A WRITING INSTRUMENT
TO A TETHER
TECHNICAL FIELD
The current disclosure relates to a device for securing a writing instrument
to a tether,
and more particularly to a device for releasably securing a writing instrument
to the
tether.
BACKGROUND
Writing instruments such as the ubiquitous ball point pens are used
extensively in banks,
offices, department stores, and in most customer service kiosks where they are
used for
filling out forms and documents, and signing receipts for purchases. Many of
these pens
end up missing or lost and must be replaced. A common way to secure a writing
device
such as a pen is to tether it to a fixed base by means of a flexible cable or
chain. One of the
earliest examples can be found in U.S. Pat. No. 3,570,284 granted to Hendircks
on Mar. 16,
1971. The writing pen lock or variations of this invention can be found in a
large number of
institutions. However, it is not uncommon to find the pen lock out of ink,
damaged, or
detached from the cable or chain.
It would be desirable to have a device capable of releasably securing a
writing instrument to
a tether.
SUMMARY
In accordance with the present disclosure there is provided a locking
mechanism for
releasably securing a writing instrument to a tether, the locking mechanism
comprising:
a housing having an opening at a first end for receiving an end portion of the
writing
instrument, the housing couplable to the tether; a plurality of resilient
teeth within the
housing, the plurality of resilient teeth extending radially inwards and away
from the first
end of the housing in a longitudinal direction when the writing instrument is
received
within the locking mechanism; and a slidable collar at least partially within
the housing
to displace the plurality of resilient teeth radially outwards for releasing
at least one
resilient tooth of the plurality of resilient teeth from the writing
instrument.
In an embodiment, the plurality of resilient teeth are located on a locking
washer.
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In a further embodiment, the plurality of resilient teeth are located on at
least a first and
second locking washer.
In a further embodiment, the first and second locking washers have different
bore sizes
to secure writing instruments having different widths, the first locking
washer having a
larger bore size than the second locking washer, and the first locking washer
located
between the second locking washer and the opening of the housing.
In a further embodiment, the slidable collar comprises a first portion for
displacing
resilient teeth on the first locking washer and a second portion for
displacing resilient
teeth on the second locking washer.
In a further embodiment, the first portion of the collar comprises a first set
of prongs for
expanding the resilient teeth on the first locking washer and the second
portion
comprises a second set of prongs, extending past the first set of prongs, for
expanding
the resilient teeth on the second locking washer.
In a further embodiment, a contact portion of the slidable collar extends past
the
housing, the contact portion providing a contact surface for moving the
slidable collar in
order to displace the at least one resilient tooth of the plurality of
resilient teeth.
In a further embodiment, the contact portion extends at least partially about
a portion of
the housing.
In a further embodiment, the slidable collar is adapted to be engaged by a
release key
for moving the slidable collar in order to displace the at least one resilient
tooth of the
plurality of resilient teeth.
In a further embodiment, the housing comprises an upper housing and lower
housing
coupled together.
In a further embodiment, the upper and lower housing are coupled together
using one
or more of: a snap-fit connection; a friction-fit connection; a threaded
connection; and an
adhesive.
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In a further embodiment, the slidable collar is moveable between: a first
position in
which the slidable collar allows the plurality of resilient teeth to contact
the writing
instrument to prevent withdrawal of the writing instrument from the opening of
the
housing; and a second position in which the slidable collar displaces the
plurality of
teeth from the writing instrument.
In a further embodiment, the plurality of resilient teeth provide a biasing
force for biasing
the slidable collar to the first position.
In accordance with the present disclosure there is further provided a
releasable tether
assembly for a writing instrument comprising: a locking mechanism for
releasably
securing: a housing having an opening at a first end for receiving an end
portion of the
writing instrument; a plurality of resilient teeth within the housing, the
plurality of resilient
teeth extending radially inwards and away from the first end of the housing in
a
longitudinal direction when the writing instrument is received within the
locking
mechanism; and a slidable collar at least partially within the housing to
displace the
plurality of resilient teeth radially outwards for releasing at least one
resilient tooth of the
plurality of resilient teeth from the writing instrument; a tether securable
to a surface;
and a tether connector connecting the locking mechanism to the tether.
In an embodiment, the tether connector comprises a chain, wire or cable.
In a further embodiment, the tether comprises an opening for receiving the
writing
instrument.
In a further embodiment, the tether includes a release key for engaging the
slidable
collar.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments are described herein with reference to the appended drawings, in
which:
Figure 1 is a perspective exploded view of the components of a locking
mechanism
for releasably securing a writing instrument to a tether;
Figure 2 is an enlarged section view of the locking mechanism of Figure 1;
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Figure 3 is a perspective exploded view of the components of a further locking
mechanism for releasably securing a writing instrument to a tether;
Figure 4 is an enlarged section view of the locking mechanism of Figure 3;
Figure 5 is a perspective exploded rear view of a further locking mechanism
for
releasably securing a writing instrument to a tether;
Figure 6 is an enlarged section view of the locking mechanism of Figure 5 in
accordance with an embodiment of the invention.
Figure 7 is a perspective exploded view of the components of a further locking
mechanism for releasably securing a writing instrument to a tether;
Figure 8 is an enlarged section view of the locking mechanism of Figure 7
shown
securing a small writing instrument in accordance with an embodiment of the
invention.
Figure 9 is an enlarged section view of the locking mechanism of Figure 7
shown
securing a large writing instrument;
Figure 10 is a perspective exploded rear view of a further locking mechanism
for
releasably securing a writing instrument to a tether;
Figure 11 is an enlarged section view of the locking mechanism of Figure 10;
and
Figure 12 illustrates possible profiles of a lock washer.
DETAILED DESCRIPTION
A locking mechanism is described that is able to secure a generic writing
instrument to
a tether that may be fixed to a surface such as on store-front or office-front
counters.
The locking mechanism allows the writing instrument to be released from the
locking
mechanism, and as such, a defective, broken, or out-of-ink writing instrument
may be
easily replaced. Further, the locking mechanism is able to secure generic
writing
instruments such as common ball point pens pencils and the like. The locking
mechanism may also be used to secure non-traditional writing instruments such
as
styluses for writing on a touch sensitive surface.
The locking mechanism includes a number of internal teeth for gripping the
writing
instrument within the mechanism. A sliding collar can be pressed against one
or more
of the teeth in order to displace the tooth or teeth from the writing
instrument and allow
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the writing instrument to be removed from the locking mechanism. The locking
mechanism can hold multiple different types of writing instruments. Further,
the locking
mechanism allows the secured writing instrument to be quickly replaced without
requiring assembly or disassembly of the writing instrument of locking
mechanism.
Figure 1 shows an embodiment of a locking mechanism 100. The locking mechanism
100 comprises a plurality of resilient teeth 102 within a housing 104,
comprised of a first
housing section 106 and a second housing section 108. The two housing sections
may
be coupled together using a snap-fit comprising a protrusion 110 and
corresponding
detent 112 as depicted in Figure 2. Other connections between the two housing
sections are possible. The housing 104 may be secured to a tether 114, which
in turn
may be secured to a surface. The locking mechanism 100 may be secured to the
tether
114 by a chain, wire or cable 116. A chain sleeve 118 may retain one end of
the chain
116 within the housing 104
The resilient teeth 102 extend radially inwards and extend from an end of the
housing
through which the writing instrument 10 is inserted. The resilient teeth 102
prevent the
writing instrument 10 from being removed without first displacing at least one
of the
resilient teeth 102 from the writing instrument 10. As depicted, the resilient
teeth 102
may be provided by a lock washer 120 that has the plurality of resilient teeth
angled and
expanding inwards for gripping the writing instrument 10. Although depicted as
a
separate component, the plurality of teeth 102 may be provided as part of the
housing
104.
A sliding collar 122 is located within the housing 104 and can be moved in
order to
displace at least one of the plurality of resilient teeth 102 outwards from
the writing
instrument 10 in order to release the writing instrument and allow it to be
retracted from
the locking mechanism 100. The housing 104 may be formed from a first housing
section 106 and a second housing section 108. The first and second housing
sections
may be coupled together in various ways, including for example a snap-fit
connection, a
friction-fit connection, a threaded connection and/or an adhesive. The
separation of the
housing into two sections may simplify the assembly process of the locking
mechanism
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100 by allowing the sliding collar 122 and the lock washer 120 to be inserted
into one of
the sections and then connecting the other housing section to secure the
sliding collar
122 and lock washer 120 within the housing 104. The locking mechanism 100 is
depicted as being connected to a tether 114 with a chain 116 which a chain
slip 118
which may pass through a hole in the housing 104 of the locking mechanism. The
tether
114 may be attached to a surface such as a desk or counter to prevent the
theft or loss
of the writing instrument 10. Alternatively, the chain 116 may be connected
directly to a
surface.
Referring to the section view of the mechanism 100 shown in Figure 2, the end
of the
writing instrument 10 may be inserted into an opening in the first housing
section 106.
The writing instrument 10 passes through the sliding collar 122 and the lock
washer
120, until a butt end 12 of the writing instrument 10 contacts flanges 124 of
the second
housing section 108. The flanges 124 are angled such that the writing
instrument 10 is
aligned with the center axis of the resilient teeth 102 of the lock washer
120. The
flanges 124 may help to prevent or reduce lateral motion that could allow the
writing
instrument 10 to be removed from the locking mechanism 100 without engaging
the
sliding collar 122 to release the resilient teeth 102. As depicted, the
writing instrument
10 presses against the resilient teeth 102 of the lock washer 120. The inward
projection
of the resilient teeth 102 prevent the writing instrument 10 from being
withdrawn from
the locking mechanism 100.
Still referring to Figures 1 and 2, a removal key 126 may be used to extract
of the
writing instrument 10 from the locking mechanism 100. The removal key 60
slides onto
the body of the writing instrument 10, an internal face 128 aligns with the
locking
mechanism's housing 106 and a flange 130 that is adjacent the writing
instrument
contacts the sliding collar 122. Applying pressure to the removal key 126
pushes the
sliding collar 122 into the locking mechanism 100 and into the plurality of
resilient teeth
102. As the sliding collar 122 moves into the housing 104, angled surface 132
of the
sliding collar 122 contacts the resilient teeth and expands the diameter of
the lock
washer teeth 102 by displacing the teeth outwards. Pressing the release key
126 into
the sliding collar 122 enables the release of the writing instrument 10.
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Referring now to Figure 3, a further locking mechanism 200 is depicted. The
locking
mechanism 200 comprises a lock washer 202 with a plurality of teeth 204 for
gripping
the writing instrument 20, a sliding collar 206, and a housing body 208
comprised of a
first housing section 210 and a second housing section 212. The two housing
sections
210, 212 may be connected in various ways as described above with regard to
the
locking mechanism 100. The housing body 208 of the locking mechanism 200 is
connected to a tether fixture 214 with a chain 216 via a chain sleeve 218. The
tether
fixture 214 may be attached to a solid body such as a desk or counter to
prevent the
loss or theft of the locking mechanism 200 and the generic writing instrument
20. The
tether fixture 214 may also provide an opening which may serve as a holder for
the
writing instrument 20 when not in use.
Referring now to section view of the locking mechanism 200 shown in Figure 4,
the end
of the writing instrument 20 is inserted in the housing 208, through a sliding
collar 206
and the lock washer 202, until a butt end 22 of the writing instrument 20
contacts the
flanges 220 of the housing 208. The flanges 220 inside the second housing
section 212
are angled such that the writing instrument 20 is aligned with the center axis
of the lock
washer 202. Aligning the writing instrument 20 with the center axis of the
lock washer
202 may help prevent or reduce any lateral motion capable of forcing out the
writing
instrument 20 from the locking mechanism 200.
The writing instrument 20 may be removed from the locking mechanism 200 by
inserting the tip of the writing instrument 20 into a flanged hole 222 of the
base fixture
214 shown in Figure 4. By pulling on the tip of the writing instrument 20
through the
hole, flange 222 pushes the sliding collar 206 into the locking mechanism 202
in order
to displace the plurality of resilient teeth 204 outward away from the writing
instrument
20. As the sliding collar 206 moves into the housing 208, an angled surface
224
expands the diameter of the plurality of resilient teeth 202 of the lock
washer 204, which
enables the release of the writing instrument 20. Once released from the
locking
mechanism, the writing instrument 20 can be pulled through the hole 222 and a
new
writing instrument inserted into the locking mechanism 200.
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Figure 5 depicts a further locking mechanism 300. The locking mechanism 300
performs the same functions of locking and securing writing instruments
without the
need for a removal key as described above with regard to the locking
mechanisms 100
200. The locking mechanism 300 comprises a lock washer 302 with a plurality of
teeth
304 for gripping the writing instrument 30, a sliding collar 306, and a
housing body 308
comprising a first housing section 310 couplable to a second housing section
312. The
housing body 308 of the locking mechanism 300 may be connected to a tether
fixture
314 with a chain 316 and a chain sleeve 318. The tether fixture 314 may be
attached to
a solid body such as a desk or counter to prevent the loss or theft of the
locking
mechanism 300 and the generic writing instrument 30.
Referring to section view of the locking mechanism 300 shown in Figure 6, a
butt end
32 of the writing instrument 30 is inserted in the housing 308, through the
sliding collar
306, and the lock washer 302, until the butt end 32 of the writing instrument
30 contacts
flanges 320 of the housing 308. The flanges 320 inside the second housing
section 312
are angled such that the writing instrument 30 is aligned with the center axis
of the lock
washer 302. The flanges 320 help to prevent or reduce any lateral motion
capable of
forcing out the writing instrument 30 from the locking mechanism 300.
In contrast to the locking mechanisms 100, 200 described above, the sliding
collar 306
protrudes from, and partially surrounds, the housing 308 and is used to
displace the
resilient teeth 304 of the lock washer 302 outward from the writing instrument
30 as
shown in Figure 6. Manually pushing the sliding collar 306 into the locking
mechanism
300 forces the face of the collar 322 to widen the lock washer teeth 304 and
enables the
releases the writing instrument 30.
Referring now to Figure 7, a further locking mechanism 400 is depicted. The
locking
mechanism 400 is similar to the locking mechanisms 100, 200, 300 described
above;
however, the locking mechanism includes a plurality of lock washers. The
locking
mechanism 400 is composed of two lock washers 402, 404. Each of the two lock
washers 402, 404 comprise a plurality of resilient teeth 406, 408. The two
lock washers
402, 404 may have different internal bores. The two locking washers 402, 404
may be
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spaced apart from each other by a spacer 410. A sliding collar 412 includes a
first
portion and a second portion for engaging the first lock washer 402 and the
second lock
washer 404 respectively. The sliding collar 412, first lock washer 402, spacer
410 and
the second lock washer 404 may be located within a housing 414. The housing
414
may be provided by a first housing section 416 and a second housing section
418 that
may be coupled together, for example using a snap-fit connection or other
techniques
as described above. The housing 414 of the locking mechanism 400 may be
tethered
to a tether fixture, such as tether fixture 214 described above, with a chain
216 and a
chain sleeve 218. As described above, the base fixture 218 may be attached to
a solid
body such as a desk or counter to prevent the loss or theft of the locking
mechanism
400 and the writing instrument 40.
Referring to the section view of the locking mechanism 400 shown in Figure 8,
a butt
end 42 of a smaller diameter writing instrument 40 is inserted into the
housing 414
through an opening in an end of the first housing section 416, through the
sliding collar
412, the first lock washer 402, the spacer 410, and the second lock washer 404
until the
butt end 42 of the writing instrument 40 contacts flanges 420 of the second
housing
section 418. The flanges 420 center the writing instrument with the axis of
the first and
second locking rings 402, 404 as described with regard to the flanges of the
locking
mechanisms 100, 200, 300. In addition to the flanges 420 located on the second
housing section 418, the locking mechanism also includes flanges 422 located
on the
spacer 410 located between the first and second lock washers. The flanges 422
on the
spacer may be sized to engage with larger diameter writing instruments that
may pass
through the first lock washer 402 but not the second lock washer 404 as
depicted in
Figure 9.
Figure 9 depicts the locking mechanism 400 with a larger diameter writing
instrument
44. As depicted, a butt end 46 of the writing instrument 44 is inserted into
the housing
414, through the sliding collar 412, and the first lock washer 402 until the
butt end 46
contacts the set of flanges 422 of the spacer 410. The flanges 420, 422 are
angled such
that writing instruments of various sizes, such as writing instruments 40 or
44, are
aligned with the center axis of the lock washers 402, 404. This feature
prevents any
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lateral motion capable of forcing out the writing instruments from the locking
mechanism
400, regardless of their diameter.
The writing instruments 40 or 44 are removed from the locking mechanism 400
using
the same method as described above with regard to locking mechanism 200. The
writing instrument is inserted through the flanged hole 222 in the tether
fixture 214. The
flange of the hole engages the sliding collar 412 and moves the sliding collar
further into
the housing 414 of the locking mechanism 400. The sliding collar 412 has two
sections
for engaging the first and second lock washers respectively. The first and
second
sections of the sliding collar may comprise respective sets of prongs, with
the second
set of prongs extending past the first set of prongs. Each of the sets of
prongs of the
sliding collar 412 contact the respective lock washer and expand the diameter
of the
respective teeth 406, 408 of the lock washers by displacing the teeth
outwards. The
displaced teeth allow the writing instrument to be extracted from the locking
mechanism.
Figures 10 and 11 depict a further locking mechanism 500. The locking
mechanism 500
is similar to the locking mechanisms described above; however, rather than
having a
housing assembled from two separate components, the locking mechanism 500
comprises a single-piece housing 502. A lock washer 504 comprises a plurality
of teeth
506 for gripping a writing instrument 50. In order to facilitate insertion of
the lock washer
504 into the single-piece housing 502, the lock washer may have a slotted-ring
shape,
allowing the ring to be deformed and inserted into the housing 502 through the
opening
for receiving the writing instrument 50. Once the lock washer 504 is inserted,
a sliding
collar 506 may be inserted into the opening. As with the other locking
mechanisms
described above, the housing 502 of the locking mechanism 500 may be connected
to a
tether fixture, such as the tether fixture 114 described above, with a chain
116 and
chain sleeve 118.
The insertion and removal of the writing instrument 50 from the locking
mechanism 500
may be substantially similar to the process described above with regard to
locking
mechanisms 100 01 200.
From the above, it will be apparent that the various locking mechanisms
include a
CA 02882313 2015-02-19
housing having an opening at a first end for receiving an end portion of the
writing
instrument. A plurality of resilient teeth are located within the housing and
the plurality of
resilient teeth extend radially inwards and away from the first end of the
housing in a
longitudinal direction when the writing instrument is received within the
locking
mechanism. Additionally, the locking mechanisms include a slidable collar that
is at
least partially located within the housing. The sliding collar can displace at
least one of
the plurality of resilient teeth radially outwards for releasing the writing
instrument.
The sliding collars described above may have an angled surface on one or more
prongs
that contact one or more of the resilient teeth in order to displace the
tooth, or teeth,
away from the writing instrument. The angle of the radially outwardly
expanding
surfaces of the sliding collars may be smaller than an inward angle of the
lock washers,
or more particularly the resilient teeth of the lock washers. The smaller
angle on the
sliding collar's surface causes the internal diameter of the teeth of the lock
washer to
increase when pressure is applied to the sliding collar, for example from the
flanges on
a tether or removal key or directly to a portion of the sliding collar
extending past the
housing. The internal diameter of the resilient teeth must be smaller than the
diameter
of the writing instrument when no writing instrument is present so that the
teeth will grip
into the body of the writing instrument once inserted and prevent its removal
without first
disengaging the teeth by engaging the teeth with the sliding collar.
The housings described above may be fabricated in plastic or another material
of
sufficiently high-strength to prevent the tear out of the chain sleeve or
other wire or
cable retaining part or assembly. The two-part housing assembly may be secured
with
the annular snap-fit but could be joined using other methods such as
adhesives, friction
fit, threaded connection and/or adhesives. The lock washer may be made from a
stiff
material resistant to abrasion such as metal, and resistant to the buckling
loads applied
to the teeth if a person attempts to remove the writing instrument without
applying
pressure to the sliding collars. Although depicted as a separate component
from the
housings, it is possible for the plurality of teeth to be formed integrally
with the housing.
Alternative the housing could contain slots into which individual teeth could
be inserted.
The slots could be of the same shape as the cross section of the teeth and
could
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prevent the extraction of the individual teeth by the user. The particular
shape of the
teeth may vary to provide different gripping ability. Various variations
thereof could
incorporate locking teeth or different cross sections and different tip shape
to maximize
gripping ability of the writing instrument as shown in Figure 12. The
resilient teeth may
have a rectangular or circular cross section. The tips of the teeth may be
flat or may be
rounded in or angled.
The removal key, the tether fixtures, and the sliding collars can be made of
the same or
different materials. The tether fixture can be affixed to a flat and solid
surface using two-
sided adhesive tape or other adhesive with sufficient strength for preventing
its removal
under normal use, or can be replaced by another retention device appropriate
to the
type of cable or chain used such as a screw-in type D' coupling for the chain
or other
type of wire or cable of sufficient strength.
Various embodiments of locking embodiments have been described above. The
embodiments depicted in the Figures include various methods for fabricating,
assembling, and locking the writing instrument in device although other
methods may
be employed. For example, lock washers portrayed as distinct components may be
incorporated into other components of the device. Further, the present
invention and the
alternate embodiments can be fixed to the solid surface by means of chain or
other type
of cable of sufficient strength.
The above described locking mechanisms provide the ability to securely fasten
generic
writing instruments such as pens and pencils to a fixed base with no
modifications to the
writing instruments, as well as the ability to remove and replace defective
writing
instruments. The minimalistic design and the location of the locking mechanism
on the
writing instrument may also secure the writing instruments with minimal
interference to
the end user.
Although described above as being applicable to writing instruments, the
locking
mechanism described above could be used for securing various instruments that
have a
generally cylindrical body. Further, the shape of the components, including
the lock
washers may be adapted in order to retain objects that do not have a
cylindrical body.
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The locking mechanism may be varied in size and materials in order to secure
various
instruments including writing instruments, hand tools, etc.
While the foregoing written description of the invention enables one of
ordinary skill to
make and use what is considered presently to be the best mode thereof, those
of
ordinary skill will understand and appreciate the existence of variations,
combinations,
and equivalents of the specific embodiments, methods, and examples herein. The
scope of the appended claims should therefore not be limited by the
particularly
described embodiments, methods, and examples, but by the teachings of the
current
application as understood by one of ordinary skill in the art.
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