Note: Descriptions are shown in the official language in which they were submitted.
CA 02599704 2007-08-30
CHAIN GUIDE INSERT FOR A GARAGE DOOR
Technical Field
[0001] This invention relates generally to moveable barriers and, more
specifically, to
chain guides for garage doors.
Background
[0002] Barrier movement operators generally comprise power and control systems
for
responding to operator inputs and sensed conditions to move a barrier between
open and
closed positions with respect to an opening. The barrier may be a door, a
gate, a window, a
window shade/protector or similar apparatus. Garage door operators are a
common form of
barrier movement operator. Various types of garage door operator systems
utilize a chain to
move the garage door. In one arrangement, the chain may be engaged at one end
with a
sprocket, with the sprocket drivingly connected to a motor. The chain is
connected at another
end to the door, or to a trolley that is connected to the door. The motor
serves to rotate the
sprocket, which pushes or pulls the chain to thus raise and lower the garage
door.
100031 When the chain is being pulled to open the door, the pulling tensile
force from
the motor-driven sprocket maintains the chain in a rigid position, so that it
can easily raise the
door. However, when the chain is being pushed to close the door, the force
from the motor-
driven sprocket will cause the chain to buckle at a link. Thus, the chain may
be captured in a
guide, with the structure of the chain guide causing the chain links to stay
in a rigid linear
position, such that the compressive force on the chain from the motor-driven
sprocket can be
used to lower the door.
[0004] When the chain is captured in a chain guide, the chain creates friction
against
the surfaces of the guide, which can wear the guide material. Under tensile
force, such as
when the chain is being pulled by the motor to raise the door, the chain links
exert a force
against the walls or other structure of the chain guide. Under compressive
forces, such as
when the chain is being pushed by the motor to lower the door, the chain links
want to rotate
and the walls and structure of the chain guide prevent such rotation. Thus,
potentially greater
frictional forces are exerted against the chain guide due to the response of a
chain to the
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compressive forces. As a result, chain guides have typically required
lubrication in order to
control the friction.
[0005] One approach for lubricating the chain guide involves constructing the
guide
out of a low-friction material. However, the choice of guide material is
limited because the
guide must be made of a strong material. Such strength is required because the
guide also
acts as a support rail in many instances and thus must take the full force of
the motor with
minimal flexing. Therefore, it is often difficult to find a material that has
both the necessary
strength and the low-friction qualities that are needed: Alternatively, as
another approach, a
low-friction lubricant may be disposed on the chain guide. However, a
lubricant can require
greater maintenance, with the chain guide requiring re-lubrication after a
period of time. The
greasy nature of such lubricants can also result in the lubricated chain and
chain guides being
messy and difficult to handle. Handling of the chain during installation and
maintenance may
result in the lubricant being transferred onto the person handling the chain
guide and other
surrounding surfaces. In addition, the greasy nature of such lubricants can
also result in the
lubricated chain and chain guides collecting dust and debris. This dust and
debris increases
the friction as it collects, thereby shortening the life of the product.
[0006] Therefore, numerous issues exist with respect to the solutions offered
thus far.
As a result, a need exists for an effective friction-reducing surface for a
chain guide.
Summary
[0007] This need is met and the objects are achieved with the present
invention.
Generally speaking, pursuant to these various embodiments, a chain operator
for a barrier
movement apparatus is provided for moving a barrier between open and closed
positions.
The chain operator comprises a chain, with a portion of the chain engaged with
a sprocket. A
motor electrically powers the rotation of the sprocket to thereby move the
chain. A chain
guide comprising a channel defines a path for movement of the chain. A
friction reducing
insert is disposed in the channel of the chain guide to capture and engage the
chain and
reduce frictional forces on the chain guide as the chain moves along the
travel path.
[0008] The insert is generally configured and arranged to engageably cooperate
with
the channel to secure the insert in the channel. In one embodiment, the
channel has ridges
and the insert has corresponding grooves to secure the insert in the channel.
The cross-
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section of the insert may also be configured to cooperate with the cross-
section of the
channel. Preferably, the insert is configured and arranged to capture and
retain the chain
thereon, such as by cooperating with the contour of the chain.
[0009] In one embodiment, the sprocket is supported on a jack shaft, wherein
the
motor rotates the jackshaft to thereby rotate the sprocket. In this
embodiment, a first end of
the chain is connected to the movable barrier. In another embodiment; at least
one end of the
chain is attached to a trolley, such that the sprocket drives the chain to
move the trolley. The
trolley is connected to the movable barrier to thereby move the barrier
between open and
closed positions.
[0010] The invention may be described with greater clarity and particularity
by
reference to the accompanying drawings.
Brief Description of the Drawings
[0011] The above needs are at least partially met through provision of the
chain guide
insert for a garage door described in the following detailed description,
particularly when
studied in conjunction with the drawings, wherein:
[0012] FIG. 1 comprises a perspective view of a garage with a garage door and
trolley
door operator system as configured in accordance with various embodiments of
the invention;
[0013] FIG. 2 comprises a side view of a drive unit housing as configured in
accordance with various embodiments of the invention
[0014] FIG. 3 comprises a perspective view of a garage with a garage door and
jackshaft door operator system as configured in accordance with various
embodiments of the
invention;
[0015] FIG. 4 comprises a perspective view of a chain guide channel as
configured in
accordance with various embodiments of the invention;
[0016] FIG. 5 comprises an end view of a chain guide and insert as configured
in
accordance with various embodiments of the invention;
[0017] FIG. 6 comprises a perspective view of the chain guide and insert shown
in
FIG. 5 as configured in accordance with various embodiments of the invention;
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[0018] FIG. 7 comprises an end view of a chain guide and insert as configured
in
accordance with various embodiments of the invention;
[0019] FIG. 8 comprises a perspective view of the chain guide and insert shown
in
FIG. 7 as configured in accordance with various embodiments of the invention;
[0020] FIG. 9 comprises a view of a chain guide into which a chain has been
inserted
as configured in accordance with various embodiments of the invention;
[0021] FIG. 10 comprises an end view of a chain guide and insert as configured
in
accordance with various embodiments of the invention;
[0022] FIG. 11 comprises an end view of a chain guide and insert as configured
in
accordance with various embodiments of the invention; and
[0023] FIG. 12 comprises an end view of a chain guide and insert as configured
in
accordance with various embodiments of the invention.
[0024] Skilled artisans will appreciate that elements in the figures are
illustrated for
simplicity and clarity and have not necessarily been drawn to scale. For
example, the
dimensions and/or relative positioning of some of the elements in the figures
may be
exaggerated relative to other elements to help to improve understanding of
various
embodiments of the present invention. Also, common but well-understood
elements that are
useful or necessary in a commercially feasible embodiment are often not
depicted in order to
facilitate a less obstructed view of these various embodiments of the present
invention. It will
further be appreciated that certain actions and/or steps may be descnbed or
depicted in a
particular order of occurrence while those skilled in the art will understand
that such
specificity with respect to sequence is not actually required. It will also be
understood that the
tenns and expressions used herein have the ordinary meaning as is accorded to
such tenns
and expressions with respect to their corresponding respective areas of
inquiry and study
except where specific meanings have otherwise been set forth herein.
Detailed Description
[0025] Referring now to the drawings, and in particular to FIG. 1, a barrier
movement
apparatus, or more specifically, a garage door apparatus is shown therein. The
garage door
apparatus 10 comprises a drive unit housing 12 mounted to a ceiling of a
garage. As shown
in FIG. 2, the drive unit housing 12 includes an electric motor 30 and
sprocket 32 in driving
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connection with a chain 14, with a portion of the chain 14 engaged with the
sprocket. In FIG.
2, the sprocket 32 is shown being directly mounted to a shaft 34 of the motor
drive 30,
however, it is understood that the motor drive may be connected to the
sprocket through any
of a variety of drive assemblies, such as, for example, using additional
pulleys, sprockets,
and/or belts. The chain is preferably a roller chain. Referring to FIGS. 1 and
2, the chain 14
extends along a chain guide 16 disposed in a rail 26 that extends from the
drive unit housing
12. A trolley 18 is connected to the chain 14 and disposed on the rai126, with
the trolley 18
movable along the rail 26 by the chain 14 in the chain guide 16. An arm 20
extends from the
trolley 18 to connect the trolley 18 to a multiple paneled garage door 22. The
garage door is
mounted on a pair of side rails 24.
[0026] The garage door apparatus may use a chain formed in a chain loop that
pulls
the trolley across the rail. The chain loop is looped around the sprocket in
the drive unit
housing at one end, and around a pulley (not shown) at the door end side of
the rail.
Alternatively, the chain 14 may comprise a single length of chain that is not
looped, such as
shown in FIGS. 1 and 2. In this configuration, the chain 14 is connected at
one end to the
trolley 18 and engaged at an opposite end with the sprocket 32 in the drive
unit housing 12. The chain is supported in the chain guide 16 to prevent
buckling, particularly when the chain
is being pushed to close the garage door 22.
[0027] The motor 30 electrically powers the rotation of the sprocket 32 to
thereby
drive the chain 14 and move the trolley 18 to open and close the garage door
22. In
operation, when the motor is energized, the motor rotates the sprocket that is
engaged with
the drive chain 16 to thereby pull the chain 16 and move the trolley 18
towards the motor to
lift the door 22. As the chain is pulled, the chain 16 may be stored in a
magazine 36 (FIG. 2)
in the drive unit housing 12. When the door 22 is lowered, the motor rotates
in the opposite
direction, and the sprocket thus pushes the chain 16 in the opposite direction
to advance the
trolley 18 away from the motor to lower the door 22.
[0028] Other garage door and operator configurations are also known in the
art. In
another embodiment, an alternate garage door operator configuration may be
used. Referring
now to FIG. 3, a garage door apparatus 50 is shown. The garage door apparatus
50 comprises
a movable garage door 52 associated with a garage door opening 60, with the
garage door 52
being carried on a pair of L-shaped tracks 54. A jackshaft 58 is mounted
horizontally above
the door opening 60 and supports a pair of sprockets 62 mounted on either end
of the
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jackshaft 58 to be turned with the jackshaft. Also mounted on the jackshaft 58
are torsion
springs 66, which perform a function of counterbalancing part of the weight of
the door to
reduce the power required to raise the door 52. Other means, such as expansion
springs (not
shown), may be used to counterbalance the door weight. A drive chain 64 is
engaged with
each sprocket 62, with the chain 64 being pulled upward or pushed downward by
the sprocket
and motor to move the door. The chain is preferably a roller chain. Each chain
64 extends
along a chain guide 68, wherein the chain guide 68 is adjacent and
substantially parallel to
the door tracks 54. A first end or ends 72 of the drive chain 64 connect to a
bottom pane174
of the garage door 52.
[0029] The garage door apparatus 50 also includes a motor 70 drivingly
connected to
the jackshaft 58. In operation, when the motor is energized, the jackshaft 58
rotates and the
sprocket 62 mounted on the shaft and engaged with the drive chain 68 rotates
to pull the
chain and lift the door 52. As the door moves upward, the chain 64 may be
stored in an upper
chain guide section 76 adjacent the door track 54, or may optionally be stored
in a magazine
78. When the door is lowered, the motor rotates in the opposite direction, and
the sprocket
pushes the chain downward. As the door moves downward, the chain 64 may be
withdrawn
from the upper chain guide section 76, or may optionally be withdrawn from the
magazine
78. Alternately, for retro-fitting to an existing installation, the drive
chain can be attached
directly to a sprocket of the motor unit which is not directly attached to the
jackshaft.
(0030] A roller chain can convey forces in compression when it is supported
from
both sides of its length to keep the chain from bending. Such support can be
achieved by
passing the chain through a channel in the chain guide that defmes a travel
path for
movement of the chain. Referring to FIG. 4, a chain guide 102 is shown such as
would be
used in the garage door apparatus 10 of FIG. 1 and the garage door apparatus
50 of FIG. 3.
The chain guide 102 has a channel 104, wherein the support provided by the
channel 104
pennits the chain to be a thrust mechanism and allows the motor to push the
chain without
the chain buckling. The chain guide 102 is an extruded piece of rigid material
such as, for
example, aluminum, steel, or a hard plastic. An opening 108 of substantially
rectangular
cross section is present in the channel. A void 110 exterids through an upper
wall 124 of the
chain guide 102 throughout the length of the guide to provide access to the
chain for
connections. The void 110 results in two protrusions 112 and 114 extending
toward the center
of the guide 102. The protrusions 112 and 114 can be used to provide anti-bend
support to a
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roller chain, in addition to the anti-bend support provided by side walls 128
and 130 of the
chain guide 102.
100311 As shown in FIG. 5, a friction reducing insert 106 is disposed in the
opening
108 of the channel 104 of the chain guide 102 to capture and engage a chain
150 and reduce
frictional forces on the chain guide 102 as the chain 150 moves along the
travel path. The
chain 150 is under tensile forces when the barrier is moving to the open
position and the
chain is under compressive forces when the barrier is moving to the closed
position. The
tensile and compressive forces of the chain create frictional forces on the
chain guide as the
chain travels along the guide. Thus, the friction reducing insert serves to
reduce the frictional
forces. The insert may be made of a high molecular weight material, such as,
for example, a
thermoplastic.
[0032] As shown in FIGS. 5 and 6, the insert 106 is configured and arranged to
engageably cooperate with the channel 104 to secure the insert 106 in the
channel 104. In
this embodiment, the cross-sections of the chain guide and insert are
substantially similar,
such that the insert is nested within the channel 104 of the chain guide 102.
Thus, the insert
also has an opening 116 having a generally rectangular cross section with a
void 118 along a
top wall 126 of the insert 106 in which the chain 150 can travel. In general,
it is preferable
for the cross-section of the insert to cooperate with the cross-section of the
channel such that
the insert will securely fit into the channel of the chain guide.
[00331 The insert also has protrusions 120 and 122 for capturing a recessed
portion
152 of the chain 150 to retain the chain 150 in the insert 106 and thus in the
chain guide 102.
The chain slides into the insert 106 in the channel 104 so that the
protrusions 120 and 122
restrain the side to side movement of the chain 1 S0. Like the protrusions of
the chain guide,
the protrusions 120 and 122 of the insert 102 can be used to provide anti-bend
support to a
roller chain. Further anti-bend support is provided by side walls 132 and 134
of the insert
102. In general, it is preferable for the cross-section of the insert to be
configured to
cooperate with the contour of the chain to capture and retain the chain. By
another optional
approach, and referring now to FIGS. 7 and 8, extension portions 162 and 164
of the insert
protrusions 120 and 122 may extend up beyond the protrusions 112 and 114 of
the chain
guide 102 and wrap around a top portion of the chain guide 102, such that
substantially no
part of the chain 150 touches the chain guide 102, thus providing a lower
friction system.
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[0034] When compression forces are applied to the chain 150 in the guide 102
and
insert 106, the chain does not bend and the forces are applied along the
chain, with the
frictional forces being reduced by the insert. FIG. 9 shows a section of chain
gaide 102
having a chain 150 therein.
[0035] Another illustrative embodiment of a chain guide 202 is shown in FIG.
10. In
this embodiment, side walls 230 and 232 of the chain guide 202 may extend
above the chain
250, with protrusions 212 and 214 projecting over the chain 250 to retain the
chain in the
channel 204. The insert 206 may have the same configuration as shown in FIG.
5, with
protrusions 220 and 222 for capturing a recessed portion 252 of the chain 250
to thereby
retain the chain 250 in the insert 206. Alternatively, as shown in FIG. 11,
the side walls 330
and 332 of the chain guide 302 and the side walls 334 and 336 of the insert
306 may both
extend above the chain 350, with the chain guide 302 having protrusions 312
and 314 and the
insert 306 having protrusions 320 and 322 that both project over the chain
350.
Alternatively, only the insert may have the protrusions, with the chain guide
having straight
side walls, or the chain guide may have protrusions, with the insert having
straight side walls.
It is preferable for at least one of the chain guide or insert to have the
protrusion so as to
retain the chain in the chain guide.
[0036] In another illustrative embodiment, as shown in FIG. 12, opposing
interior
walls 440 of the channe1404 of the chain guide 402 may have ridges 442, with
corresponding
exterior walls 444 of the insert 406 having grooves 446 to thereby allow the
insert 406 to
engageably cooperate with the channe1404 of the chain guide 402.
Alternatively, the channel
may have grooves and the insert may have ridges. Further, any of a variety of
mating or
interconnecting engagements may be used to secure the,insert in the channel.
[0037] The ridge and groove configuration in FIG. 12 is shown with the chain
guide
402 having protrusions 412 and 414 and the insert 406 having protrusions 420
and 422 that
both project into the recessed mid-portion 452 of the chain 450. However, it
should be noted
that the ridge and groove configuration may be used with any of a variety of
chain guide and
insert arrangements, such as any of those described above.
[0038] Those skilled in the art will recognize that a wide variety of
modifications,
alterations, and combinations can be made with respect to the above described
embodiments
without departing from the spirit and scope of the invention, and that such
modifications,
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alterations, and combinations are to be viewed as being within the ambit of
the inventive
concept.
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