U.S. patent application number 13/726024 was filed with the patent office on 2013-06-27 for coupler.
This patent application is currently assigned to MILLER INTERNATIONAL LTD.. The applicant listed for this patent is Miller International Ltd.. Invention is credited to Gary Miller, Howard Reay.
Application Number | 20130164080 13/726024 |
Document ID | / |
Family ID | 45573005 |
Filed Date | 2013-06-27 |
United States Patent
Application |
20130164080 |
Kind Code |
A1 |
Miller; Gary ; et
al. |
June 27, 2013 |
Coupler
Abstract
A coupler (10) for securely attaching an accessory to an
excavator arm of an excavator. The coupler (10) comprises a first
half (16) for connecting to the excavator arm and a second half
(18) for connecting to the accessory. The second half comprises a
front jaw with a movable front latch associated therewith, the
front latch having a latching position and a non-latching position,
and being for latching one of two attachment pins of the accessory
within the front jaw when it is in its latching position. The
second half also has a rear latch, the rear latch having a
retracted position and an advanced position, and being for engaging
a second of the attachment pins when it is in its advanced
position. The second half also has a trigger member mounted for
movement relative to the frame, the trigger member being arranged
for movable interaction with both the front latch and the rear
latch so as to move, respectively, the front latch between its
latching position and its non-latching position and the rear latch
between its advanced position and its retracted position.
Inventors: |
Miller; Gary; (Washington,
GB) ; Reay; Howard; (Washington, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Miller International Ltd.; |
Gibraltar |
|
GI |
|
|
Assignee: |
MILLER INTERNATIONAL LTD.
Gibraltar
GI
|
Family ID: |
45573005 |
Appl. No.: |
13/726024 |
Filed: |
December 22, 2012 |
Current U.S.
Class: |
403/327 ;
403/326; 403/373 |
Current CPC
Class: |
E02F 3/3627 20130101;
Y10T 403/60 20150115; E02F 3/365 20130101; Y10T 403/7062 20150115;
E02F 3/3663 20130101; E02F 3/3604 20130101; E02F 3/3622 20130101;
E02F 3/3618 20130101; E02F 3/3672 20130101; Y10T 403/602
20150115 |
Class at
Publication: |
403/327 ;
403/373; 403/326 |
International
Class: |
E02F 3/36 20060101
E02F003/36 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2011 |
GB |
1122270.0 |
Claims
1. A coupler for attaching an accessory to an excavator arm of an
excavator, the coupler comprising a frame with a first half for
connecting to the excavator arm and a second half for connecting to
the accessory, the second half comprising: a front jaw with a
movable front latch associated therewith, the front latch having a
latching position and a non-latching position, and being for
latching one of two attachment pins of the accessory within the
front jaw when it is in its latching position; a rear latch, the
rear latch having a retracted position and an advanced position,
and being for engaging a second of the attachment pins when it is
in its advanced position; and a trigger member mounted for movement
relative to the frame, the trigger member being arranged for
movable interaction with both the front latch and the rear latch so
as to move, respectively, the front latch between its latching
position and its non-latching position and the rear latch between
its advanced position and its retracted position.
2. The coupler of claim 1, wherein the trigger member is pivotally
mounted relative to the frame.
3. The coupler of claim 1, wherein the coupler additionally
comprises a rear jaw associated with the rear latch, and the rear
latch at least partially closes its associated rear jaw when in its
advanced position.
4. The coupler of claim 1, wherein the front latch is pivotable
between its latching position and its non-latching position.
5. The coupler of claim 1, wherein the rear latch is permanently
biased towards its advanced position.
6. The coupler of claim 1, wherein either the front latch is biased
towards its latching position by gravity when the coupler is
oriented such that the first half is above the second half, or the
front latch is permanently biased towards its latching position by
a spring.
7. The coupler of claim 1, wherein the front latch is bifurcated,
and has two pivot pins, each being coaxial and extending in a
lateral direction relative to the frame of the coupler.
8. The coupler of claim 1, wherein the front latch has a blocking
member extending therefrom, the blocking member being arranged to
locate in front of an end of the rear latch when the rear latch is
in its advanced position and simultaneously the front latch is in
its latching position.
9. The coupler of claim 1, wherein the trigger member comprises at
least three protruding surfaces--a first protruding surface for
interacting with the front latch, a second protruding surface for
interacting with the rear latch, and a third protruding surface for
interacting with a pin of the accessory.
10. The coupler of claim 1, wherein the rear latch has an
upstanding flange thereon, the flange having an end or surface for
interaction with the trigger member.
11. The coupler of claim 1, wherein interaction between the trigger
member and the two latches causes the trigger member to move those
latches when itself is moved, the interaction being such that there
is at least one transitional resistance point.
12. The coupler of claim 11, wherein to move the second latch from
the retracted position to an advanced position, at least one of the
transitional resistance points has to be overcome, whereupon the
movement of the latches into their advanced or latching positions
occurs under the impulse of the mechanism as a whole.
13. The coupler of claim 12, wherein the impulse of the mechanism
as a whole is driven at least in part by one or more of a spring
bias for the rear latch and a spring bias for the front latch.
14. The coupler of claim 11, wherein at least one of the
transitional resistance points is provided by providing a flat or
flattened portion on an end of a protruding surface of the trigger
member.
15. The coupler of claim 11, wherein at least one of the
transitional resistance points is provided by providing a concavity
on the trigger member into which a concave surface of one of the
latches latch can selectively rest.
16. The coupler of claim 1, wherein the trigger member has a hole
in it for receiving a latch disengagement bar therein, whereby,
with the latch disengagement bar, the trigger member can be forced
to move, thereby interacting with the two latches.
17. The coupler of claim 1, wherein the front latch is pivotably
mounted to the frame at a position lying more rearward than a pivot
point of the trigger member.
18. The coupler of claim 1, wherein the front latch is biased into
its latching position by a spring that is positioned generally
above the trigger member.
19. The coupler of claim 1, wherein the front latch has one or more
arms adopting the general shape of an M, with two upper peaks, two
dropping ends and a dipping middle, and a blocking member for
selectively blocking retraction of the rear latch from an advanced
position into a retracted position in which a pin cannot be
disengaged from the coupler is formed on, or is attached to, the
dipping middle of the one or more arms.
20. The coupler of claim 19, wherein the trigger member interacts
with the front latch in an inside of an upper peak thereof.
Description
TECHNICAL FIELD
[0001] The present invention relates to a coupler for coupling an
accessory to an excavator arm of an excavator. One such accessory
could be an excavator bucket.
BACKGROUND OF THE INVENTION
[0002] Couplers for coupling accessories to the excavator arm of an
excavator are well known in the art. Indeed many prior art patents
and patent applications describe such couplers. See, for example,
GB2330570, GB21 77674, EP0184282, U52005169703A1, U.S. Pat. No.
6,699,001, WO2010/059948, GB2412361, GB24631 58, GB2447809 and
WO2008/031590.
[0003] These couplers generally comprise a top half that is
connectable to an excavator arm using two attachment pins (via two
pairs of holes provided for those attachment pins) and a bottom
half for engaging two further attachment pins, on the accessory.
For that latter purpose that bottom half typically comprises two
jaws, rather than holes. Those jaws engage respective ones of those
two further attachment pins of the accessory.
[0004] A common feature of many couplers is that a first of the two
jaws is usually referred to as a front jaw. Its opening (for
receiving the first or front attachment pin) is generally directed
out of the front end of the coupler, i.e. generally parallel to an
imaginary line joining the two pairs of holes in the top half of
the coupler. Often it is angled slightly upwards from that line,
perhaps at an angle of up to 15.degree..
[0005] The second jaw is then usually referred to as a rear jaw. It
generally points downwardly, i.e. in a direction that is generally
perpendicular to the front jaw.
[0006] The rear jaw commonly has an associated latching hook. The
latching hook can be slid or pivoted between a latched position and
an unlatched position. In the latched position, the opening of rear
jaw is at least partially closed by the latching hook. In the
unlatched position, however, the latching hook is usually fully
retracted so as to leave the jaw's opening open so that the
attachment pin can be removed from the jaw downwardly.
[0007] The coupler in GB2330570 also features a blocking bar which
is adapted to fall under the influence of gravity (when in normal,
in-use, orientations of the coupler, i.e. non-inverted
orientations) into a blocking position in front of the latching
hook. In that blocking position, the blocking bar will resist the
unlatching of the latching hook by blocking its path from its
latching position into an unlatched position.
[0008] The blocking bar is pivotally mounted about a pivot. That
pivot is positioned near the front jaw. The blocking bar therefore
points generally towards the rear jaw from that pivot and is
balanced about that pivot such that gravity will usually urge it
towards its blocking position, i.e. while the coupler is in the
normal, in-use, orientations, i.e. rather than upside down or
partially inverted. Then, in order to unblock the latching hook
(for decoupling the accessory from the coupler), either the coupler
would need to be inverted or else some form of urging means would
be provided for lifting the blocking bar from its blocking position
into a non-blocking position. One such urging means could be a
small hydraulic ram.
[0009] During normal use, i.e. when digging with a bucket, very
high forces can be loaded onto the latching hook by the attachment
pins of the accessory. Occasionally those forces may be
transferred, at least in part, onto the blocking bar. In order to
cope with those forces, therefore, the blocking bar is usually a
rather substantial element. This is to prevent the blocking bar
from buckling under those occasional loads.
[0010] Other couplers are disclosed in U.S. Pat. No. 6,699,001 and
GB2447809. In those documents, the rear pivoting latching hook is
replaced by a sliding member.
[0011] Further couplers are disclosed in GB2463158 and
WO2008/031590. In those couplers, both jaws feature a pivotable
latch.
[0012] The movement of the latches can be by a spring bias, or by a
mechanical actuator (usually either a hydraulic ram or a large
screw-thread drive, or for the case of the front latch, by gravity.
The movement of the blocking bar, where provided, can also be by
actuator or gravity. For the actuator, it is typically a separate
hydraulic ram to the ram for the rear latch.
[0013] The latching and securing actions, and also the later
detachment/disconnection actions on these couplers, typically have
to be performed using a series of predefined steps since the
mechanisms such as the latches for each jaw, and any blocking means
therefor, are designed not to actuate together so as to prevent
inadvertent detachment. What would be desirable, however, would be
to provide a coupler arrangement in which latches are still blocked
from inadvertent detachment, but in which a single element can
trigger the secured attachment of an accessory in the first place,
and likewise cause a required detachment or disconnection of an
accessory to occur. It is important, however, for the coupler still
to feature the requisite precautionary, effective, but generally
redundant, latch back-up mechanisms so as to prevent inadvertent
detachment upon a failure of an element within the coupler.
SUMMARY OF THE INVENTION
[0014] According to embodiments of the present invention there is
provided a coupler for attaching an accessory to an excavator arm
of an excavator, the coupler comprising a frame with a first half
for connecting to the excavator arm and a second half for
connecting to the accessory, the second half comprising: [0015] a
front jaw with a movable front latch associated therewith, the
front latch having a latching position and a non-latching position,
and being for latching one of two attachment pins of the accessory
within the front jaw when it is in its latching position; [0016] a
rear latch, the rear latch having a retracted position and an
advanced position, and being for engaging a second of the
attachment pins when it is in its advanced position; and [0017] a
trigger member mounted for movement relative to the frame, the
trigger member being arranged for movable interaction with both the
front latch and the rear latch so as to move, respectively, the
front latch between its latching position and its non-latching
position and the rear latch between its advanced position and its
retracted position.
[0018] Preferably the trigger member is pivotally mounted relative
to the frame.
[0019] Preferably the trigger member directly bears against either
one or both of the latches.
[0020] Preferably the trigger member is mounted within a rear half
of the coupler. The rear half of the coupler can be defined as any
point rearwards of a lateral plane extending between sideplates of
the frame, which plane is located midway between the rearmost lip
of the rear latch when the rear latch is in its most retracted
position and the rearmost part of the front jaw.
[0021] The trigger member is preferably arranged above a rear jaw
of the coupler, the rear jaw being a second jaw, and it being
associated with the rear latch.
[0022] Preferably the front latch is pivotable between its latching
position and its non-latching position.
[0023] Preferably the front latch at least partially closes its
associated front jaw when in its latching position.
[0024] Preferably the rear latch at least partially closes its
associated rear jaw when in its advanced position.
[0025] Preferably the accessory couples to the coupler by a two-pin
attachment, wherein the front jaw engages a first one of those two
pins and the rear latch engages the second of those two pins, the
rear latch cooperating with the frame and the front jaw to provide
the engagement force for retaining the first pin in the front jaw
and the second pin against the rear latch.
[0026] Preferably the mode of attachment includes first engaging
the first pin in the front jaw, and then engaging the second pin
with the rear latch
[0027] Preferably the front jaw is a first jaw and the rear latch
is associated with a second jaw--a rear jaw.
[0028] Preferably the rear jaw faces a different direction to the
first jaw. Preferably the rear jaw faces a direction that is
perpendicular to the direction of the first jaw.
[0029] Preferably the second jaw has a wider opening than the first
jaw--this allows for accessories from different manufacturers to be
accommodated--pin diameters of the attachment pins, for a given
application/machine load rating, tend to be generally similar, i.e.
rarely differing by more than 5%, but pin centre spacings can vary
more than that, e.g. often by up to 15% between manufacturers.
[0030] The rear latch will typically be permanently biased towards
its advanced position. The bias may be provided by a spring, such
as a coil spring. There may be more than one such coil
springs--preferably there are two. This ensures that if one fails,
the other will still provide a desired bias towards a latching
position.
[0031] The front latch may be permanently or selectively biased
towards its latching position. Selective bias may be provided by
gravity, e.g. when the coupler is appropriately oriented. In
another arrangement the bias may be permanent, such as by a spring,
such as a coil spring. There may be more than one such coil
springs, but often just the one will be enough, especially if
gravity can provide a redundant back-up bias.
[0032] Further bias might be provided by selectively operable
hydraulic rams, potentially with selectively operable oil circuit
bypasses, thereby allowing actions from the trigger member to not
need to overcome such hydraulic bias forces.
[0033] Preferably the rear jaw points directly away from the first
(top) half of the coupler, i.e. it is a downwardly facing jaw.
[0034] Preferably the front jaw faces substantially forwards or
generally longitudinally, i.e. generally along the long-axis of the
coupler (or generally parallel to an imaginary line extending
between the centres of the two attachment pins of the
accessory--once correctly mounted onto the coupler). The front jaw
in further arrangements may face slightly upwards of that
longitudinal line, but preferably by no more than 15.degree. from
that line.
[0035] The rear latch will usually comprise a nose portion having a
substantially constant or solid section that extends between two
jaw members, one in each sidewall of the frame.
[0036] The front latch will usually comprise a nose portion having
substantially constant or solid cross section that extends
downwardly into the mouth of the front jaw, the throat of the front
jaw, and the bottom lip of the front jaw, both having a
substantially constant or solid cross section.
[0037] The or each jaw, or jaw part, will usually be provided with
a reinforced or hardened steel insert to provide additional
strength for the jaw. That additional strength assists the jaw to
accommodate the heavy loading that will be applied to it during the
use of the coupler.
[0038] Preferably the accessory is an excavator bucket.
[0039] Preferably the front latch is merely a generally redundant
back-up mechanism for the coupler, the rear latch and front jaw
providing the primary latching mechanism for the accessory to the
coupler. As a redundant back-up mechanism, the front latch serves
to secure the accessory to the coupler in the event of a failure in
the primary latching mechanism, such as if the rear latch bends or
breaks off. As such, the front latch is unlikely actually to engage
against an attachment pin that might be engaged within the front
jaw, even though it laches that pin within that jaw.
[0040] Preferably the front latch has a centre of gravity such that
disengagement of the front latch from its latching position into
its non-latching position cannot occur, purely under the influence
of gravity, through a range of angles of rotation from the upright
horizontal working position in which the longitudinal axis, or at
least 80.degree. in each direction.
[0041] With the spring bias, that angle can increase beyond
90.degree., and even beyond 180.degree. so as to provided full
inversionability without a compromise to the attachment
condition.
[0042] Preferably the front latch has a pivot pin about which it
can rotate, that pivot pin extending in a lateral direction
relative to the frame of the coupler.
[0043] Preferably the front latch is bifurcated, and has two pivot
pins, each being coaxial and extending in a lateral direction
relative to the frame of the coupler.
[0044] Preferably the or each pivot pin is positioned in a rear
half of the coupler.
[0045] Preferably the front latch includes one or more arm member
extending from a nose portion to a pivot pin. The arm is preferably
substantially flat in one plane--preferably a vertical,
longitudinal plane.
[0046] Preferably the arm has a blocking member extending
therefrom, the blocking member being arranged to locate in front of
an end of the rear latch when the rear latch is in an advanced
position and simultaneously the front latch is in a latching
position. The blocking member thus serves to prevent the rear latch
from being retracted into its retracted position until the front
latch has been moved into a non-latching position.
[0047] Preferably the arm has a trigger interaction region.
Preferably the trigger interaction region has a latch-open region,
against which the trigger member can bear when the trigger member
is interacting therewith to hold the front latch in a non-latching
position. Preferably the trigger interaction region has a
latch-closed region, against which the trigger member can bear when
the trigger member is interacting therewith with the front latch in
a latching position.
[0048] The trigger interaction region is preferably blended so as
to offer a smooth, curved surface against which the trigger member
can slide, e.g. when moving between the latch-open region and the
latch-closed region thereof.
[0049] Preferably there are two arms, and preferably they mirror
one another.
[0050] Preferably the trigger member comprises at least three
protruding surfaces--a first protruding surface for interacting
with the front latch, e.g. as described above with respect to the
trigger interaction region thereof, a second protruding surface for
interacting with the rear latch, and a third protruding surface for
interacting with a pin of the accessory, e.g. within a rear jaw of
the coupler.
[0051] The protruding surfaces preferably are rounded or smooth,
rather than pointed or rough. This is to assist with interactions
with the surfaces against which they bear. The surfaces may even
feature bearings to further improve the low-resistance interaction
between the surfaces.
[0052] The rear latch is preferably arranged for transitional
movement along tracks within the sidewalls of the frame.
[0053] The rear latch preferably has a tapered end in cross
section. This facilitates an insertion of an attachment pin past
the end in the event that the end is not fully retracted.
[0054] The front latch may also be adapted for facilitated
insertion of an attachment pin past the end thereof, e.g. past the
end of its nose portion, in the event that the end is not fully
moved into a non-latching position. For this purpose, the end may
present an outwardly facing angled surface, or a rounded surface,
whereby a pin would force the end upwards due to an angle of a
reactionary force generated thereby.
[0055] The rear latch preferably has an upstanding flange thereon,
the flange having an end or surface for interaction with the
trigger member--e.g. the second protruding surface thereof.
[0056] The interaction between the trigger member and the two
latches causes the trigger member to move those latches between
their relatively open and relatively closed positions, as described
above with reference to latching/non-latching positions and
advanced/retracted positions. That interaction can be such that
either the first or the second, or both the first and the second,
protruding surfaces of the trigger have a transitional resistance
point at one or both ends of their travels, such that to retract or
open the latches (i.e. to move them to a retracted or non-latching
position), at least one of the transitional resistance points has
to be overcome, whereupon the release or opening of the latches
occurs under the impulse of the mechanism as a whole, or becomes
easier to achieve, or more preferably to move from the released or
open condition of the latches, at least one of the transitional
resistance points has to be overcome, whereupon the movement of the
latches into their advanced or latching positions occurs under the
impulse of the mechanism as a whole, e.g. driven by the spring bias
of the rear latch.
[0057] The transitional resistance points can be provided by
providing a smoothly stepped surface on the trigger interaction
region, or by providing a smoothly stepped surface on the flange of
the rear latch, or by providing a flat or flattened portion on the
end of the relevant protruding surface of the trigger member, or by
providing a concavity on the trigger member into which a concave
surface of the relevant latch can rest.
[0058] Preferably the trigger member has a hole in it for receiving
a latch disengagement bar therein, whereby, with the latch
disengagement bar, the trigger member can be forced to rotate about
its pivot, thereby interacting with the two latches.
[0059] Preferably the rear end of the frame has an elongated
aperture through which that latch disengagement bar can be threaded
to access the hole in the trigger member.
[0060] Alternatively the trigger may be power actuated, e.g. by
having a screwdrive or hydraulic ram associated therewith.
Preferably that actuator can be disengageable so as to prevent the
possibility of an accidental actuation.
[0061] The may be a blocking member or safety pin for preventing
unintentional release of the trigger member.
[0062] The front latch is preferably pivotably mounted to the frame
at a position lying more rearward than the pivot point of the
trigger member. The hole in the trigger member is preferably
accessible between two arms of that front latch.
[0063] The front latch may be biased into its latching position by
a spring that is positioned generally above the trigger member. The
spring may act against a bridge spanning between two arm members of
the front latch.
[0064] The front latch may have one or more arms adopting the
general shape of an M, with two upper peaks, two dropping ends and
a dipping middle. This shape will be lighter than a bar with
substantially straight top and bottom walls.
[0065] Preferably the blocking member is formed on, or is attached
to, the dipping middle.
[0066] Preferably the pivot point is arranged at an end of one of
the dropping ends.
[0067] Preferably the nose portion is arranged at the other
dropping end.
[0068] Preferably the trigger member interacts with the front latch
in the inside of the upper peak that lies nearest the pivot
point.
[0069] Preferably the front jaw has a cut-out in its lower lip, the
cut-out extending across the full extent of the jaw. The cut-out is
to accommodate an attachment pin to provide a further resistance to
a pin exiting the front jaw--due to the outer lip formed
thereby.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0070] These and other features of the present invention will now
be described, by way of example only, with reference to the
accompanying drawings.
[0071] FIG. 1 schematically shows a first embodiment of the
invention in a jaw open condition.
[0072] FIG. 2 shows a cut-away perspective of the embodiment of
FIG. 1.
[0073] FIG. 3 shows the embodiment of FIG. 1 but in a jaw closed
configuration.
[0074] FIG. 4 shows a cut-away perspective of the embodiment of
FIG. 3.
[0075] FIG. 5 shows the embodiment of FIG. 1, but in which a
release member has opened the jaws, whereby the attachment pins are
released from those jaws.
[0076] FIG. 6 shows in more detail the trigger member of the
embodiment of FIGS. 1-5.
[0077] FIG. 7 shows a perspective view of a further embodiment of
the present invention.
[0078] FIG. 8 shows a side elevation of the embodiment of FIG.
7.
[0079] FIG. 9 schematically shows the internal mechanisms of the
embodiment of FIG. 7, with the internal mechanisms in a jaws-open
configuration.
[0080] FIG. 10 schematically shows the embodiment of FIG. 7 with
the internal mechanisms in a jaws-closed configuration.
[0081] FIG. 11 shows the front latch of the embodiment of FIG. 7
separated from the rest of the coupler to more clearly illustrate
its shape.
[0082] FIG. 12 shows a third embodiment of the present
invention.
[0083] FIG. 13 shows a side elevation of the embodiment of FIG.
12.
[0084] FIG. 14 schematically shows the internal mechanisms of the
embodiment of FIG. 12; with the internal mechanisms in a jaws-open
configuration.
[0085] FIG. 15 schematically shows the embodiment of FIG. 12 with
the internal mechanisms in a jaws-closed configuration.
DETAILED DESCRIPTION OF THE INVENTION
[0086] Referring first of all to FIG. 1, a coupler for attaching to
an arm of an excavator is shown. It is for attaching accessories
onto the arm of the excavator. Such accessories include buckets and
other tools. They are mounted via attachment pins--two parallel
attachment pins.
[0087] The coupler 10 of this first embodiment has a first (or top)
half 12 and a second (or bottom) half 14. The first half 12 has two
holes 16, 18 therein for receiving attachment pins of the arm of
the excavator. The second half instead has two jaws--a front jaw 20
and a rear jaw 22. These are for receiving attachment pins 30, 36
of the accessory.
[0088] The front jaw 20 has an upper wall 24 and a lower wall 26
and a throat at its back 28. One of the attachment pins 30 of an
accessory will, in use, sit towards the back 28 of that front jaw
20, i.e. when properly coupled to the coupler 10.
[0089] The front jaw 20 has a recess 32 towards the free end of its
lower wall 26. That recess 32 is shown to be sized also to seat
such an attachment pin 30. This recess 32 therefore provides a
means of resistance against exiting of the attachment pin 30 from
the front jaw 20, e.g. in the event that it becomes loose within
the jaw 20. This works efficiently due to the weight of the
accessory naturally pulling the pin into the recess--something that
can happen throughout most in-use (i.e. digging) orientations of
the coupler 10. However, when the coupler is properly coupled, this
recess 32 serves no function.
[0090] The front jaw 20 has its opening oriented to point generally
in the forwards direction of the coupler 10, i.e., it opens
essentially in a direction extending parallel to the longitudinal
axis of the coupler (or directly away from the rear jaw).
[0091] The rear jaw 22 is spaced from the front jaw, rearwardly
with respect to the coupler 10. Its opening faces generally
downwards, away from the first half 12 of the coupler 10. Its
opening has a width 34 which is typically wider than the height of
the opening of the front jaw 20. In this embodiment, that width 34
is relatively narrow compared to many prior art universal couplers
since this coupler is designed more for a specific range of
accessories--i.e. accessories having a narrow range of pin-centre
spacings. A wider rear jaw 22 would permit a greater range of
pin-centre spacings to be accommodated by the coupler, and the
coupler may be thus adapted.
[0092] A second of the attachment pins 36 is arrangeable within the
rear jaw 22 and ultimately will be captured therein at a full-depth
insertion into that rear jaw 22, as shown in FIG. 3.
[0093] Associated with that rear jaw, there is provided a trigger
member 38. The trigger member 38 is in this embodiment a generally
triangular sectioned member (in cross section, in a vertical,
longitudinal plane of the coupler). Importantly, though, it has a
protruding surface 40 that can selectively extend into the rear jaw
22 for interaction with the second attachment pin 36. This is so
that as the second attachment pin 36 is inserted into the rear jaw
22, it can bear against that protruding surface 40 so as to
activate the internal latching mechanism of the coupler, as
explained below.
[0094] That trigger member 38 is mounted for rotation relative to
the frame of the coupler 10 by a pivot pin 42. That pivot pin 42
extends laterally across the width of the frame of the coupler 10,
and can be mounted to the sidewalls of the frame. As the second
attachment pin 36 pushes against the protruding surface 40 of the
trigger member 38, the trigger member 38 will rotate as shown by
arrow 44--as illustrated this is in a clockwise direction.
[0095] The trigger member 38 additionally has two further
protruding surfaces--a front latch engaging protruding surface 46
and a rear latch engaging protruding surface 48, better seen in
FIG. 3. These three protruding surfaces 40, 46, 48 are shown to be
at the approximate corners of the trigger member.
[0096] As a result of these three protruding surfaces, and their
interaction with other elements of the coupler/accessory, the
trigger member 38, in response to insertion of the second
attachment pin 36 into the rear jaw 20, can operate both the front
and rear latches 50, 52. These interactions will each be discussed
below.
[0097] The front latch 50 takes the form of a latching end, an arm
and a hingepoint. In this embodiment, it adopts a generally M
shaped form, when viewed in side elevation, or a U shaped form when
viewed from above. The U and M shapes offer a useful means for
fitting the front latch within and around other components of the
working mechanism of the coupler, but while still ensuring
stability and strength.
[0098] The front latch has a pivotable connection to the frame at a
first end 54. For that purpose, a pair of pivot pins 56 are
provided--see FIG. 2. There are two pivot pins 56 since the front
latch 50 is a bifurcated member having two substantially identical
arms 58 that extend substantially along the full length of the
coupler 10 (the uprights of the U), which arms extend away from the
latching end (located at the far end from the pivot pins--i.e. the
base of the U).
[0099] The front-latch-engaging protruding surface 46 of the
trigger member 38 engages on an underside of the arms 58 so as to
be able to lift the front latch 50 from a latching position for
rotation about the pivot pins 56 into a non-latching position.
[0100] The free end of the latch 50--the latching end--is instead
provided with a nose portion 60 which is adapted to descend through
a hole (not shown, but see the cut-aways of FIGS. 2 and 4) in the
upper wall 24 of the front jaw 20 so as to selectively close the
front jaw 20--the latching position. When lifted, however, the
front jaw will be open--the non-latching position.
[0101] The nose portion is shown to be curved on both an inside
face and an outside face. These serve to assist in ensuring firstly
that a pin 30 cannot exit past the latch 50 (since the inside curve
catches the pin and imparts a closing moment on the latch), and
secondly that a pin can enter the front jaw if the latch is closed
(since the outer curve engages the pin and imparts a lifting moment
on the latch. Instead of the curves, however, the surfaces may
instead be angled so as to point down and rearwardly, e.g. towards
the recess.
[0102] Towards the middle of the front latch 50 there is also
provided a blocking member 62. This blocking member--here in the
form of a shark-fin--is for interaction with the rear latch 52, as
will be explained below, and is for securing that rear latch in its
pin engaging state when the front latch 50 is in its latching
position, as shown in FIG. 3.
[0103] The front latch's M shape also provides two peaks. One is to
accommodate the trigger member 38--in an underside thereof. The
other is to take the latch over the top of an attachment point 63
of a biasing member 68 for the rear latch 52.
[0104] The front latch's M shape also provides a middle trough.
This provides a position for the blocking member 62, whereby the
blocking member 62 is low enough to engage behind the rear latch
52.
[0105] The front latch's M shape also provides the two
end-legs--they provide respectively the first end for the pivotable
mounting of the front latch 50 to the frame of the coupler 10 and
the second end which provides the latching end and nose portion
60.
[0106] As can be seen in FIG. 2, the two arms 58 of the front latch
have a generally constant transverse thickness with respect to the
frame of the coupler. They also extend from the latching end/nose
portion 60. The latching end instead is a solid member--it has a
substantially solid cross section, were arranged to extend between
the ends of the two arms 58 by being welded thereto.
[0107] Referring now to the rear latch 52, it comprises a sliding
plate 72 having edges 64 (see FIG. 2) for sliding in tracks 66 in
the side walls of the frame of the coupler 10. The rear latch,
therefore, rather than being pivotably mounted relative to the
frame is arranged for sliding in and out of a retracted and
advanced position, with the advanced position being such as to
secure a pin within the rear jaw, as shown in FIG. 3. Pivoting
arrangements, however, are also envisaged.
[0108] To provide a bias for that sliding motion towards the
advanced position of FIG. 3, a pair of coiled springs 68 are
provided, spaced laterally relative to one another with respect to
the frame of the coupler 10, and affixed at their other ends to
block that is affixed in place by a removable pin that extends
through an attachment point 63. This arrangement--with the
removable pin--permits the springs to be removed, and thus the
plate to be serviced.
[0109] A single spring could be enough, instead of the illustrated
two, although two springs provides a redundant spring in the event
of a failure of one of the springs.
[0110] The plate of the rear latch 52 can have an underside
reinforcement member 70 to provide additional strength to the free
end of the nose of that rear latch. This is useful since this rear
latch will be exposed to the digging forces of the excavator during
use.
[0111] The plate 72 also has at its enclosed end a pair of angled
surfaces 74--see FIG. 3. The angled surfaces 74 are for interacting
with the blocking members 62 on the arms of the front latch. A
single angled surface may be enough--on one side--e.g. if the front
latch has only a single arm.
[0112] The angled surfaces 74 are adapted to face correspondingly
angled surfaces on the blocking members 62. The angles are chosen
so as to be oriented so as to prevent digging forces applied by the
second attachment pin 36 on the rear latch 52 from forcing the rear
latch 52 rearwardly past the blocking member 62 (i.e. downwardly
and rearwardly with respect to the coupler). This can be achieved
since increased forces on the rear latch--trying to cause the plate
to slide towards a retracted position--will tighten the angled
surface 74 of the plate against the shark fin, thus improving the
connection between the shark fin blocking member 62 and the angled
surface 74. Angling them in the other direction, however, would
instead cause the arm to lift in that scenario, which would be
undesirable.
[0113] That angled surface is preferably at least 10.degree. from
perpendicular to the plane of the plate 72.
[0114] On the top side of the plate 72 a further member of the rear
latch is provided--an upwardly extending flange 76. The upwardly
extending flange 76, in this embodiment, has an angled rearward
face 78 and a recess 80 in its top--see FIG. 4. The angled rearward
face 78 is angled by perhaps 5 or more degrees from the
perpendicular with respect to the plane of the plate 72. That angle
cooperates with the rear-latch-engaging protruding surface 48 of
the trigger member 38 so as to reduce the amount of rotation needed
by that trigger member 38 for releasing the rear latch 52. However,
it is optional--it is not present, for example, in the embodiment
of FIG. 9.
[0115] The upwardly extending flange also provides a recess 80 at
its end. The recess defines a ridge 82 that the end of the
rear-latch-engaging protruding surface 48 of the trigger member 38
can rest upon when the trigger member is in its primed
condition--i.e. with the rear latch retracted and the front latch
lifted, as shown in FIG. 2.
[0116] By having the ridge, a transitional resistance point is
provided between the trigger member and the rear latch, which
transitional resistance point has to be overcome before the trigger
mechanism can be released. Thereafter the spring of the rear latch
can propel the rear latch into its extended position for engaging
an attachment pin in the rear jaw 22.
[0117] A further transition resistance point is provided by the
front-latch-engaging protruding surface 46 since it has a flat face
that rests against the underside of the arm 58 when in the primed
condition of FIG. 1. Therefore, a rotation of the trigger member
will initially lift the front latch above its primed position
before dropping it down into its latching position.
[0118] With the above described arrangement, therefore, from the
condition of FIG. 1, upon inserting a pin 36 into the rear jaw 20
of the coupler 10, the trigger member 38 rotates in the clockwise
direction 44 so as to move the front-latch-engaging protruding
surface on the underside of the arm 58 and the rear-latch-engaging
protruding surface over the ridge 82 of the recess 80 and then onto
the angled rearward face 78 of the rear latch 52. That then allows
the spring bias of the springs 68 to force the rear latch 52 into
its advanced position of FIG. 3 and the front latch 50 will also
pivot down into its latching position, whereupon the condition of
FIG. 3 is arrived at. In this condition, the blocking member 62 has
been brought into position behind the rear latch 52, thereby
preventing retraction of the rear latch 52 back into its retracted
position of FIG. 1. The two jaws 20, 22 are thus both closed, with
pins therein being either latched or secured their respective
coupled positions.
[0119] Referring next to FIG. 5, a release of those attachment pins
is shown. In that Figure, and with reference to FIG. 6, the trigger
member 38 has a hole 86 in a rearwardly facing surface 84 thereof.
That hole 86 is for accommodating an end of a release bar--a lever
arm 88. The lever arm 88 can extend through a slot 90 in the rear
end of the frame of the coupler 10, as shown with respect to the
second embodiment in FIG. 7.
[0120] A downward leverage force 92 on the free end of the lever
arm 88 can then force the rotation of the trigger member in an
opposite (anti-clockwise) direction, as signified by the arrow 94
in FIG. 5. This then causes the rear-latch-engaging protruding
surface 48 of the trigger member 38 to ride up the angled rearward
face 78 of the rear latch, thus tending to force that rear latch
into its retracted position. Simultaneously (or preferably just
prior to that, for preventing the blocking member preventing that
retraction), it also lifts the front latch 50 due to the
front-latch-engaging protruding surface 46 of the trigger member
riding up on the inside of the arm 58 so as also to lift the
blocking member 62 away from the path of the angled surface 74 of
the plate 72 of the rear latch 52. The two jaws 20, 22 can thus be
opened by that lever arm 88, and the pins 30, 36 can then be
removed as shown.
[0121] Referring next to FIGS. 7 to 15, two further embodiments of
the present invention are shown in which many features are similar
to the first embodiment. For example, there are still the trigger
members, the front latches, the rear latches, the front jaws, the
rear jaws, the pairs of coil springs and the various pivot points.
They may not be identical in shape or form, but they are still
there. However, in these later two embodiments the front latch 50
is biased into a latching position by a further coil spring 96.
This further coil spring 96 pushes against a bridge 98 extending
between the two arms 58 and is located thereon by a peg 100. The
spring bias helps to bias the front latch towards its latching
position, and prevents the front latch from opening if the coupler
is inverted, for from opening if the coupler is exposed to high
vibrational forces (e.g. due to pneumatic hammer actions, as often
used on excavator tools).
[0122] In place of the illustrated spring bias, alternative
positions for that spring are possible. Further, a bias towards a
latching position can be provided by many other mechanisms, such as
by leaf springs--e.g. ones that engage against the arm of the
excavator, such as the one shown in GB 2330570 for the blocking bar
in that coupler.
[0123] In addition, apertures 102 are provided in the frame of the
coupler for accommodating a safety pin--see FIG. 10. Those
apertures 102 can accommodate a safety pin, e.g., that laterally
extends through the sidewalls of the frame of the coupler so as to
prevent a lifting of the front latch 50. FIG. 9 shows how holes
overlie the path of the arm of the front latch, whereby a safety
pin would foul against that arm, thus resisting a lifting of the
front latch from a latching position. If used, the safety pin would
need to be removed when releasing the coupler.
[0124] As briefly mentioned above, in these second and third
embodiments, the shapes of the trigger member 38 are different.
Likewise the shapes of the front and rear latches are slightly
different. However, the functionality is the same as with the first
embodiment in that there are still front- and rear-latch-engaging
protruding surfaces on the trigger members, and also the protruding
surfaces for engagement against the second attachment pins within
the rear jaws 22. There are also the blocking members 62 for
engaging angled surfaces 74 in the non-free ends of the plates 72
of the rear latches 52. A further discussion of the functionality
of these additional embodiments is therefore not needed herein
since the above described first embodiment operates in a
sufficiently close manner.
[0125] The frames of the couplers will typically be cast
substantially in a single piece, although hardened steel inserts
might be added/welded therein post casting. Alternatively the
frames can be fabricated from plate steel using known cutting and
welding techniques.
[0126] The other components such as the latches and the trigger
members can also be cast, although they can instead be fabricated
from plate steel using known cutting and welding techniques.
[0127] The present invention therefore provides an easily
activatable, and an easily releasable, coupler that still offers
the secured attachment of the prior art--with the numerous (more
than one) redundant safety features, such as the blocking member
for the rear latch, the curved front latch, the concealed
(non-externally accessible--it requires the use of a lever arm)
release trigger member and the front latch per se.
[0128] It should be appreciated that the invention has been
described above purely by way of example. However, modifications in
detail may be made to the invention as limited purely by the claims
appended hereto.
* * * * *