`
`(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property Organization _
`International Bureau
`
`' |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
`
`(43) International Publication Date
`20 March 2008 (20.03.2008)
`
`(51) International Patent Classification:
`E02F 3/36 (2006.01)
`
`(21) International Application Number:
`PCT/EP2007/007974
`
`(22) International Filing Date:
`13 September 2007 (13.09.2007)
`
`(25) Filing Language:
`
`(26) Publication Language:
`
`English
`
`English
`
`(30) Priority Data:
`06180343
`06201396
`07023724
`
`13 September 2006 (13.09.2006)
`11 October 2006 (11.10.2006)
`17 February 2007 (17.02.2007)
`
`GB
`GB
`GB
`
`(71) Applicant and
`(72) Inventor: HILL, Ian [GB/GB]; 8 Glenvale Heights,
`Newry, Co Down BT34 2RN (GB).
`
`(10) International Publication Number
`
`WO 2008/031590 A2
`
`(81) Designated States (unless otherwise indicated, for every
`kind of national protection available): AE, AG, AL, AM,
`AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ, CA, CH,
`CN, CO, CR, CU, CZ, DE, DK, DM, DO, DZ, EC, EE, EG,
`ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL,
`IN, IS, JP, KE, KG, KM, KN, KP, KR, KZ, LA, LC, LK,
`LR, LS, LT, LU, LY, MA, MD, ME, MG, MK, MN, MW,
`MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PG, PH, PL,
`PT, RO, RS, RU, SC, SD, SE, SG, SK, SL, SM, SV, SY,
`TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA,
`ZM, ZW.
`
`(84) Designated States (unless otherwise indicated for every
`kind of regional protection available): ARIPO (BW, GH,
`GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM,
`ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
`European (AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI,
`FR, GB, GR, HU, IE, IS, IT, LT, LU, LV, MC, MT, NL, PL,
`PT, RO, SE, SI, SK, TR), OAPI (BF, BJ, CF, CG, CI, CM,
`GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG).
`
`Published:
`
`(74) Agents: WALLACE, Alan et al.; ER. Kelly & C0., 4
`Mount Charles, Belfast BT7 1NZ, Northern Ireland (GB).
`
`— without international search report and to be republished
`upon receipt of that report
`
`(54) Title: COUPLER FOR EXCAVATORS
`
`i,
`
`[0
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`f
`
`
`
`
`
`//.
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`\ 27.
`
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`
`
`15
`
`Ha
`
`Ln.
`
`
`
`
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`(57) Abstract: A coupler for an excavator, the coupler comprising first and second recesses for receiving the pins of an attachment,
`a latching hook movable into and out of a latching state in which it closes the second pin—receiving recess, and a blocking bar movable
`into and out of a blocking state in which a portion of the blocking bar closes the first recess. The arrangement is such that, when the
`blocking bar is engaged in use by an attachment pin contained within the first recess, the action of the pin on the blocking bar urges
`the blocking bar into its blocking state. The blocking bar is further arranged so that, in the blocking state, it lies in the path of the
`latching hook and that, upon movement of the latching hook out of the latching state, the latching hook engages with the blocking
`bar to retain it in the blocking state.
`
`Page 1 of 36
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`CATERPILLAR EXHIBIT 1003
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`/031590A2|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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`00
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`ccN W
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`0
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`Page 1 of 36
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`CATERPILLAR EXHIBIT 1003
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`

`

`WO 2008/031590
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`PCT/EP2007/007974
`
`Coupler for Excavators
`
`Field of the invention
`
`The present invention relates to a coupler for excavators. The invention relates
`
`particularly to couplers having power operated latching hooks.
`
`Background to the Invention
`
`10
`
`15
`
`It is well known for a coupler to have a hydraulically operated latching hook for
`
`engaging with the pins of an attachment, e.g. a bucket, for the arm of an excavator.
`
`Such couplers typically include a safety mechanism for preventing the attachment
`
`from becoming disengaged from the coupler in the event of hydraulic failure.
`
`It is an object of the present invention to provide an alternative, improved safety
`
`mechanism.
`
`Summary of the Invention
`
`20
`
`Accordingly, the invention provides a coupler for an excavator, the coupler
`
`comprising a body having first and second recesses for receiving first and second
`
`pins, respectively, of an attachment; a latching member movable into and out of a
`
`latching state in which it at least partially closes said second pin-receiving recess;
`
`and a blocking member movable into and out of a blocking state in which a
`
`portion of the blocking member at least partially closes said first recess.
`
`Preferably, said portion of the blocking member is shaped so that, when engaged
`
`in use by an attachment pin contained within said first recess, the action of the pin
`
`on said portion urges said blocking member into its blocking state.
`
`25
`
`3O
`
`Preferably, the blocking member is arranged so that, in the blocking state, it lies in
`
`the path of the latching member and that, upon movement of the latching member
`
`Page 2 0f 36
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`CONFIRMATION COPY
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`Page 2 of 36
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`WO 2008/031590
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`PCT/EP2007/007974
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`out of the latching state, the latching member engages with the blocking member
`
`to retain it in the blocking state.
`
`Typically, the latching hook and/or the blocking bar are mounted, more preferably
`
`pivotably mounted, on the body.
`
`In the preferred embodiment, a lever is mounted on the body and is movable into
`
`and out of a holding state in which it is capable of holding the blocking bar out of
`
`the blocking state, the lever being coupled to the latching hook to move into the
`
`10
`
`holding state when the latching hook is moved out of the latching state and to
`
`move out of the holding state when the latching hook moves into the latching state.
`
`Preferably, the lever is pivotably mounted on the body at or adjacent the rear of
`
`the latching hook. Advantageously, the lever is resiliently biased into contact with
`
`15
`
`the rear of the latching hook.
`
`In the preferred embodiment, the latching hook carries a cam and the lever
`
`includes a cooperating ramped cam surface, the cam being arranged to ride along
`
`the cam surface as the latching hook moves into and out of its latching state, the
`
`cam surface being shaped to cause the angle of inclination between the latching
`
`hook and the lever to increase as the hook moves out of the latching state and to
`
`decrease as the hook moves into the latching state.
`
`The coupler may include a biasing means, such as a leaf spring, torsion spring or
`
`other biasing member, coupled to the blocking bar and arranged to engage with an
`
`excavator arm to which the coupler is attached during use depending on the
`
`relative orientation of the coupler and the arm, wherein in a first relative
`
`orientation of the coupler and the arm, the biasing means is held under tension
`
`between the arm and the blocking bar urges the blocking bar into its blocking
`
`state. Alternatively, the biasing member may be coupled to the excavator arm and
`
`arranged for engagement with the blocking member.
`
`20
`
`25
`
`30
`
`Page 3 0f 36
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`Page 3 of 36
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`WO 2008/031590
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`PCT/EP2007/007974
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`In a preferred embodiment, the biasing means, in the preferred form of a leaf
`
`spring, comprises a bent or crank portion located at or near its free end. In use, the
`
`end of said crank portion engages the excavator arm in the first relative orientation
`
`of the coupler and arm.
`
`Further advantageous aspects of the invention will become apparent to those
`
`ordinarily skilled in the art upon review of the following description of a specific
`
`embodiment of the invention and with reference to the accompanying drawings
`
`10
`
`Brief Description of the Drawings
`
`Embodiments of the invention are now described by way of example and with
`
`reference to the accompanying drawings in which like numerals are used to
`
`indicate like parts and in which:
`
`15
`
`Figure 1 is a cut-away side view of a coupler embodying the invention, the coupler
`
`being shown in a first state of use;
`
`Figure 2 is a cut-away side View of the coupler of Figure 1, the coupler being
`
`20
`
`shown in a second state of use connected to an attachment with minimum pin
`
`spacing;
`
`Figure 3 is a cut-away side View of the coupler of Figure 1, the coupler being
`
`shown in a third state of use;
`
`25
`
`Figure 4 is a cut-away side view of the coupler of Figure 1, the coupler being
`
`shown in the second state of use but connected to an attachment with maximum
`
`pin spacing;
`
`30
`
`Figure 5 is a cut-away side view of the coupler of Figure 1 connected to an .,
`
`excavator arm, the arm and the coupler being shown in a normal working
`
`orientation;
`
`Page 4 0f 36
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`Page 4 of 36
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`WO 2008/031590
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`PCT/EP2007/007974
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`Figure 6 is a cut-away side view of the coupler of Figure 1 connected to an
`
`excavator arm, the arm and the coupler being shown in a first inverted, or
`
`overhead, orientation;
`
`Figure 7 is a cut-away side view of the coupler of Figure 1 connected to an
`
`excavator arm, the arm and the coupler being shown in a second inverted, or
`
`overhead, orientation;
`
`1 0
`
`Figures 8 to 11 show an alternative embodiment of the coupler in respective
`
`different orientations;
`
`Figure 12 to 16 show a further alternative embodiment of the coupler wherein the
`
`biasing means includes a bent portion;
`
`15
`
`Figure 17 is a cut-away side View of a still further alternative embodiment
`
`including a safety locking pin;
`
`Figure 18 is a sectional end view of the coupler Figure 17 showing the safety pin
`
`2 0
`
`in a retracted state;
`
`Figure 19 is a sectional View of the coupler Figure 17 showing the pin in an
`
`engaged state.
`
`2 5
`
`Detailed Description of the Drawings
`
`Referring now to the drawings there is shown, generally indicated as 10, a coupler
`or hitch for connecting a tool or attachment, such as a bucket, to a jib or arm 12 I
`
`(Figures 5 to 16) of an excavator (not shown), or other apparatus. The coupler 10
`
`3 O
`
`has a body 14 typically comprising two spaced-apart side plates 15 (only one
`
`shown). The body 14 is shaped to define pin-receiving apertures 16, 18 by which
`
`the coupler 10 may be connected to the end of the arm 12. Typically, there are two
`
`Page 5 0f 36
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`Page 5 of 36
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`

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`WO 2008/031590
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`PCT/EP2007/007974
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`spaced-apart apertures 16, 18 in each of the two side plates 15, the apertures in one
`
`side plate being aligned with the apertures in the other. Figures 5 to 16 show the
`
`coupler 10 connected to the arm 12 at one set of apertures 16 only although in
`
`practice the other set of apertures 18 are usually connected to a linkage (not
`
`shown) carried by the arm 12. When connected, the coupler 10 is able to pivot
`
`with respect to the arm 12 about the axis of the apertures 16, as is apparent by
`
`comparing Figures 5 to 7. Usually, a hydraulic mechanism, or other power
`
`operated mechanism (not shown), is provided to pivot the coupler 10 with respect
`
`to the arm 12.
`
`10
`
`15
`
`20
`
`25
`
`The body 14 includes first and second pin-receiving recesses 20, 22 formed in
`
`each side plate 15. Each recess 20, 22 is shaped and dimensioned to receive a
`
`respective pin 24, 26 of a bucket or other attachment. Normally, the recesses 20,
`
`22 face in mutually perpendicular directions. The recess 22 may be wider than is
`
`necessary to receive a single pin 26 in order to accommodate attachments with
`
`different pin spacings, as is illustrated by pin 26’.
`
`The coupler 10 also includes a power-operated latching mechanism typically
`
`comprising a latching hook 30 and an actuator 32 typically in the form of a
`
`hydraulic ram. Other forms of powered actuator could be used (e. g. pneumatic or
`
`electrically operated) but hydraulic is convenient because excavators typically
`
`have a hydraulic system available at or near the end of the arm 12. The latching
`
`hook 30 and ram 32 are provided between the side plates 15 . The latching hook
`
`30, which may comprise one or more aligned hook elements, is pivotably mounted
`
`on the body 14 in any convenient manner and is pivotable about an axis A which
`
`runs substantially perpendicular to the body l4/plates 15. The hook 30 is
`
`pivotable between an open state (shown in Figures 1 and 3) and at least one
`
`latching state (shown in Figures 2 and 4). In the open state, the latching hook 30
`
`allows the pins 26, 26’ to be inserted into or removed from the recess 22. In the
`
`30
`
`latched state, the latching hook 3O prevents the pins 26, 26’ from being removed
`
`from the recess 22. In alternative embodiments, the hook may be slidably mounted
`
`Page 6 of 36
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`Page 6 of 36
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`

`

`WO 2008/031590
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`PCT/EP2007/007974
`
`on the body, or otherwise movable between the open state and the latching state(s),
`
`without necessarily being pivotable.
`
`In the preferred embodiment, the ram 32 has its butt end 34 pivotably mounted on
`
`5
`
`the body 14 and the free end 36 of its piston rod 36 is pivotably connected to the
`
`latching hook 30, in each case the pivoting movement being about a respective
`
`axis that is substantially perpendicular to the plates 15. When the piston rod 36
`
`adopts a retracted state (Figures 1 and 3), the latching hook 30 adopts its open
`
`state. When the piston rod 36 is extended, the hook 30 moves towards its latching
`
`l 0
`
`state. Depending on the location of the pin 26, 26’ in the recess 22, the amount by
`
`which the piston rod 36 is extended when the hook 30 reaches its latching state can
`
`vary, as can be appreciated from a comparison of Figures 2 and 4. Conveniently,
`
`the ram 32 is operable Via the excavator’s hydraulic system (not shown), the
`
`controls typically being located in the cab of the excavator.
`
`1 5
`
`The coupler 10 further includes a blocking member in the preferred form of a bar
`
`40 which has one end 42 pivotably mounted on the body 14 in any convenient
`
`manner, e. g. pin or bearing. The blocking bar 40 is pivotable about an axis
`
`substantially perpendicular to the side plates 15 between a non-blocking state
`
`2 0
`
`(Figure 1) and a blocking state (Figure 2). In the non-blocking state, the blocking
`
`bar 40 is clear of the recess 20 and does not prevent the pin 24 from being
`
`removed from the recess 20, while in the blocking state, the blocking bar 40
`
`prevents the pin 24 from being removed from the recess 20. In the preferred
`
`embodiment, the blocking bar 40 includes a jaw 44 which, in the blocking state,
`
`2 5
`
`substantially closes the otherwise open mouth of the recess 20. The jaw 44 may
`
`form part of a recess 46 provided in the blocking bar 40, which recess 46, in the
`
`blocking state, embraces the pin 24 located in the recess 20.
`
`In the preferred arrangement, the end 42 of the blocking bar 40 is pivotably
`
`3 O
`
`mounted on the body 14 beyond the recess 20 with respect to the latching hook 30.
`
`This allows the blocking bar 40 to be shaped and dimensioned so that its other end
`
`48 lies in the path of the latching hook 30 when in the blocking state.
`
`Page 7 0f 36
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`Page 7 of 36
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`

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`WO 2008/031590
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`PCT/EP2007/007974
`
`In the preferred embodiment, a lever 50 has one end 52 pivotably mounted on the
`
`body 14 and is positioned so that its other end 54 may be located in the path of the
`
`blocking bar 40. The lever 50 is movable between a holding state (Figure 1) in
`
`5
`
`which its end 54 engages with the blocking bar 40 in order to hold the blocking
`
`bar 40 in its non-blocking state, and a non-holding state (Figures 2 to 4), in which
`
`the lever 50 does not interfere with the movement of the blocking bar 40. In the
`
`preferred embodiment, the lever 50 is located adjacent the rear of the latching
`
`hook 30 and is resiliently biased by a Spring 56, or other biasing means, to move
`
`1 0
`
`towards and into engagement with, the rear of the hook 30. The arrangement is
`
`such that movement of the latching hook 30 between its latching and open states
`
`causes a corresponding movement of the lever 50. In particular, when the latching
`
`hook 30 adopts its open state, the lever 50 adopts its holding state. In the preferred
`
`embodiment, the rear of the latching hook 30 carries a cam 60 and the lever 50
`
`1 5
`
`includes a cooperating, and preferably ramped, cam surface 62. The cam 60 rides
`
`along the cam surface 62 as the latching hook 30 moves between its latching and
`
`open states, the cam surface 62 being shaped to cause the angle of inclination
`
`between the latching hook 30 and the lever 50 to increase as the hook 30 moves
`
`towards the open state and to decrease as the hook 30 moves towards the latching
`
`2 0
`
`state. This has the effect of pushing the lever 50 away from the rear of the hook 30
`
`as the hook 30 is retracted. Arcs Al and A2 show the respective paths taken by
`
`the lever 50 and the blocking bar 40.
`
`In alternative embodiments (not illustrated), the lever 50 may be independently
`
`2 5
`
`operated by, for example, a hydraulic ram or other actuator, or may be integrally
`
`formed with the latching hook. Alternatively still, the blocking bar 40 may be
`
`held in the non-blocking state by the latching hook itself (when retracted) or a
`
`projection therefrom.
`
`3 O
`
`In a first state of use (Figure I), the latching hook 30 is open, the blocking bar 40
`
`is in its non-blocking state and is held by the lever 50 which adopts its holding
`
`state. In this state of use, the recesses 20, 22 are substantially unobscured and so
`
`Page 8 0f 36
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`Page 8 of 36
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`WO 2008/031590
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`PCT/EP2007/007974
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`are ready to receive attachment pins 24, 26, 26’. Normally, an operator (not
`
`shown) in the cab of the excavator manoeuvres the coupler 10 to capture the first
`
`attachment pin 24 in recess 20 and then rotates the coupler 10 to capture the
`
`second pin 26 or 26’. The operator then operates the ram 32 to move the latching
`
`5
`
`hOok 30 into its latching state (Figures 2 and 4). Movement of the latching hook
`
`30 causes the lever 50 to move out of its holding state which in turn allows the
`
`blocking bar 40 to move from the non-blocking state to the blocking state. In the
`
`illustrated embodiment, the blocking bar 40 adopts the blocking state under the
`
`influence of gravity but, in alternative embodiments (not illustrated) the blocking
`
`l 0
`
`bar 40 may be resiliently biased by a spring, or other biasing means, to adopt the
`
`blocking state, and/or may be power operated by any suitable actuator (e. g.
`
`pneumatic, hydraulic or electrical). Hence, Figures 2 and 4 show the coupler 10 in
`
`a second state of use in which the latching hook 30 holds the pin 26or 26’
`
`in the
`
`recess 22, while the blocking bar 40 holds the pin 24 in the recess 20.
`
`1 5
`
`Should the latching hook 3O retract during use, for example as a result of hydraulic
`
`failure of the ram 32 or by operator error, the end 48 of the blocking bar 40 is
`
`located in the path of the latching hook 30 such that the latching hook 30 engages
`
`with the blocking bar 40 (see Figure 3, although a small clearance is shown in
`
`20
`
`Figure 3 for reasons of clarity). This engagement serves to hold the blocking bar
`
`40 in its blocking state. Hence, in a third state of use, the latching hook 30 is in its
`
`open state, but retains the blocking bar 40 in its blocking state and so the pin 24 is
`
`secured in recess 20 and the attachment cannot disengage from the coupler 10
`
`In order to disengage the attachment from the coupler 10, the latching hook 30
`
`2 5 must at the outset be in its latching state as shown in, for example, Figure 5. The
`
`coupler 10 is inverted (Figure 6) by appropriate manoeuvring of the arm 12 until
`
`the blocking bar 40 falls under the influence of gravity to the non-blocking state.
`
`Subsequently, the latching hook 30 is retracted to its open state causing the lever
`
`50 to hold the blocking bar 40 in its non-blocking state. The attachment may then
`
`30
`
`be disengaged from the coupler 10.
`
`Page 9 0f 36
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`Page 9 of 36
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`WO 2008/031590
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`PCT/EP2007/007974
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`If it is desired to maintain the blocking bar 40 in its blocking state while the
`
`coupler 10 is inverted, this may be achieved by means of a biasing member 70 and
`
`appropriate manoeuvring of the arm 12 and coupler 10. In the preferred
`
`embodiment, the biasing member 70 comprises a leaf spring, or other elongate
`
`5
`
`resilient and flexible member, and has one end fixed to, or engagable with, the
`
`blocking member 40. The arrangement is such that, by pivoting the coupler 10
`
`with respect to the arm 12, the other end of the leaf spring 70 may be caused to
`
`engage with the arm 12, the action of the arm 12 on the spring 70 causing the
`
`spring 70 to push the blocking bar 40 into the blocking state (Figure 7). The
`
`10
`
`spring 70 maintains the blocking bar 40 in the blocking state as long as the relative
`
`angular orientation between the coupler 10 and the arm 12 is maintained.
`
`In Figure 5, the coupler 10 is shown in a working orientation wherein the recesses
`
`20, 22 face generally downwards, i.e. generally towards the ground. In contrast, in
`
`1 5
`
`Figures 6 and 7 the coupler is inverted such that the recesses 20, 22 face generally
`
`upwardly, i.e. away from the ground. The orientation shown in Figure 6 may be
`
`referred to as an upside down orientation wherein the relative angular orientation
`
`between the coupler and the arm 12 is such that the blocking bar 40 is able to fall,
`
`under gravity, out of the blocking position and is not prevented from doing so by
`
`2 0
`
`interaction between the biasing member 70 and the arm 12. The orientation of
`
`Figure 7 may be referred to the overhead orientation. In the overhead orientation,
`
`the relative angular relationship between the coupler 10 and the arm 12 is such that
`
`the interaction between the biasing member 70 and arm 12 hold the blocking bar
`
`40 in its blocking position (unless the lever 50 is preventing it from doing so).
`
`2 5
`
`Hence, the upside down orientation may be adopted when it is desired to
`
`disengage an attachment from the coupler 10, whereas the overhead orientation
`
`may be adopted if it is desired to work with the coupler in an inverted position.
`
`In the foregoing description, it is described how the latching hook 30 is capable of
`
`30
`
`holding the blocking bar 40 in its blocking state, as shown for example in Figure 3.
`
`In preferred embodiments, however, the blocking bar may be held in its blocking
`
`state by the action of the pin 24 against the blocking bar 40 itself. This
`
`Page 10 0f 36
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`WO 2008/031590
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`PCT/EP2007/007974
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`10
`
`arrangement, which is described in more detail below, may act in conjunction with
`
`‘
`
`the action of the hook 30 against the blocking bar 40, or may serve to hold the
`
`blocking bar in its blocking state even when the latching hook 30 is not
`
`sufficiently retracted to prevent the blocking bar from leaving its blocking state.
`
`5
`
`For example, if the coupler 10 is being used with an attachment having relatively
`
`wide pin spacings (e.g. the pins may be the pins 24, 26/ shown on the drawings),
`
`then it will be seen that the latching hook 30 may withdraw to an extent where it
`
`allows the pin 26/ to leave to recess 22, but not be sufficiently far retracted to
`
`interfere with the movement of the blocking bar 40.
`
`10
`
`In such an event, pin 26 may fall out of recess 22 and cause the attachment (not
`
`shown) to swing with respect of the coupler 10 about pin 24. This tends to cause
`
`pin 24 to engage with the jaw 44 of the blocking bar 40. The engagement of the
`
`pin 24 with the jaw 44, urges the blocking bar into its blocking state, or more
`
`1 5
`
`particularly, has the effect of holding the blocking bar 40 in its blocking state.
`
`This is because the action of the pin 24 on the jaw 44 urges the blocking bar 40 to
`
`pivot about pivot point 42 in an anti—clockwise direction (as shown in Figure 3).
`
`In the preferred embodiment, this is achieved by providing the jaw 44 with a
`
`curved surface (concave in the illustrated embodiment), the centre of the curved
`
`2 0
`
`surface preferably being located between the centre of the pin 24 (when in the
`
`recess 20) and the pivot point 42 of the blocking bar 40 in a vertical direction as
`
`viewed in Figure 2. It will be understood however that the jaw may take other
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`shapes and configurations to the same effect.
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`2 5
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`In an alternative embodiment (Figures 8 to 11), the leaf spring may be replaced by
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`an alternative biasing member, such as a torsion spring 80, a compression spring,
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`or other resilient biasing member arranged between the blocking bar 40 and the
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`arm 12. In the case of a torsion spring, the spring 80 may comprise two legs 82,
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`84 and a coil portion 86, the coil portion 86, for example, being mounted on the
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`30
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`body at or around the end 34 of the ram 32, one leg being arranged for engagement
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`with the blocking bar, the other being arranged to engage with the arm 12 when
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`the coupler adopts the position of Figure 7 or 11. Figures 8 to 11 illustrate the
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`action of the spring 80 under four different orientations of the coupler.
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`In Figure
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`8, the coupler is shown in a normal working orientation and the torsion spring 80
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`is not in contact with the dipper arm 12. In Figure 9, the coupler is inverted (e. g.
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`corresponding to the upside down orientation of Figure 6) to allow the blocking
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`bar 40 to fall out of its blocking state under gravity. In Figure 10, the coupler is in
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`an overhead position in which the torsion spring 80 acts between the arm and bar
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`40 to hold the blocking bar 40 in its blocking state. In Figure 11, the coupler is in
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`an overhead position in which the spring 80 is in a compressed state since the lever
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`50 holds the blocking bar in its blocking position.
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`10
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`Alternatively still, one or more powered actuators (not shown), e.g. hydraulic,
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`pneumatic or electric actuators, may be provided for actuating the blocking bar 40
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`between its blocking and non-blocking states, or at least from one of said states to
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`the other. In such an embodiment, the lever 50 and the biasing member 70 are not
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`15
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`required. The actuator(s) may be operated in any convenient manner, e.g. by
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`separate controls in the cab of the excavator or other machine.
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`In Figures 12 to 16 a further alternative embodiment is shown, in which the
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`biasing member 170 preferably comprises a leaf spring, or other elongate resilient
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`20
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`and flexible member, and has one end connected or coupled to the blocking bar 40
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`and having an angled or bent portion 171 at its other end. The angled portion 171
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`is arranged so that it extends from the remainder of the biasing member 170 in a
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`direction towards the arm 12 when the coupler is in its overhead position.
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`25
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`The spring 170 has a body portion 172 connected or coupled to the blocking bar
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`40 at one end, and the angled or crank portion 171 at the other end. The crank
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`pertion 171 extends obliquely from the body portion 172 in a direction generally
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`towards the arm 12 when the coupler 10 is in the overhead position (Figure 12).
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`The arrangement is such that, when the coupler 10 is in the overhead position (e. g.
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`3O
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`as shown in Figure 12) the end of the leaf spring 170 engages with the arm 12 and
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`the action of the arm 12 on the leaf spring 170 causes the spring 170 to urge the
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`blocking bar 40 into the blocking state. The shape of the spring 170 generates
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`extra force when compared to the spring 70 and so provides extra support when
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`holding the blocking bar 40 in the blocking state.
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`In the preferred arrangement, the biasing member 170 and arm 12 are arranged so
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`that there is a gap (indicated as B in Figure 14) between the leaf spring 170 and
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`arm 12 during use when the leaf spring 70 is not engaged with the arm 12
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`(Figures 14 to 16). The gap B allows the blocking bar 40 to move from its
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`blocking state to its non-blocking state without interference by interaction of the
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`spring 170 and arm 12.
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`It will be apparent that the couplers 10 may operate substantially in the same
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`manner as described with reference to Figures 1 to 7.
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`It will be seen that in the configuration of Figure 13, the body portion 172 of the
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`spring 170 engages with the arm 12, whereas in the configuration of Figure 12, the
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`bent portion 171 engages with the arm 12.
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`Referring now to Figures 17to 19, there is shown a still further embodiment of a
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`coupler 110 which is similar to the couplers 10 described in Figures 1 t016 and
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`respect of which similar descriptions apply as will be apparent to those skilled in
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`the art. The coupler 110 includes a locking mechanism in the preferred form of a
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`safety pin device 190 comprising a safety pin 192 moveable between a retracted
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`state (Figure 18) and an engaged state (Figure 19). The pin 192 is preferably
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`resiliently biased, e.g. by means of a compression spring 194, to adopt the engaged
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`state. The safety pin device 190 is mounted on the body of the coupler 110 and is
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`positioned so that, when the pin 192 is in the engaged state, it lies in the path of
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`the blocking bar 40 in order to prevent the blocking bar 40 from leaving its
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`blocking state.
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`10
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`15
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`20
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`25
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`3O
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`The pin 192 is slideably located in a channel 196 formed in the body of the
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`coupler 110. The channel 196 also retains the spring 194. Conveniently, the pin
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`192 is provided with a handle 198. As shown in Figure 18, the handle 198 may be
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`rotated about the axis of the pin 192 and to engage with an abutment 199 to lock
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`the pin 192 in its retracted state against the bias of the spring 194. When the
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`handle is rotated out of engagement of the abutment 199 and released, the action
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`of the spring urges the pin 192 into its engaged state (Figure 19).
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`It will be apparent that the location of the safety pin device 190 determines the
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`amount by which the blocking bar 40 may move away from its normal blocking
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`state. At the very least, the safety pin device 190 should be positioned so that the
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`blocking bar 40 is not able to move out of its blocking state to the extent that its tip
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`1 0
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`can be lifted by the tip of the lever 50.
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`It will be understood'that in any or all of the aforementioned embodiments, the
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`latching hook 30 may be comprised of one or more hooks, and the blocking bar 40
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`may be comprised of one or more blocking bars (see Figures 18 and 19 where two
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`1 5
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`spaced apart blocking bars 40, 40/ are shown, each co—operating with the recess
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`20). In the case where there are two or more components to either the latching
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`hook or the blocking bar, the respective components may or may not be connected
`
`together. Typically, they are connected together and move as a respective unit and
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`so may be considered as a single latching hook or a single blocking bar even
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`2 0
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`though it may be comprised of two or more spaced apart components.
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`The invention is not limited to the embodiments described herein which may be
`
`modified or varied without departing from the scope of the invention.
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`25
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`Claims:
`
`1. A coupler for an excavator, the coupler comprising a body having first and
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`second recesses for receiving first and second pins, respectively, of an attachment;
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`a latching member movable into and out of a latching state in which it at least
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`partially closes said second pin-receiving recess; a blocking member movable into
`
`and out of a blocking state in which a portion of the blocking member at least
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`partially closes said first recess.
`
`10
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`2. A coupler as claimed in claim 1, wherein said blocking member is pivotably
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`mounted to the body at a pivot point, said first recess being located substantially
`
`between said latching member and said pivot point.
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`3. A coupler as claimed in claim 1 or 2, wherein said portion of the blocking
`
`15
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`member is shaped so that, when engaged in use by an attachment pin contained
`
`within said first recess, the action of the pin on said portion urges said blocking
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`member into its blocking state.
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`4. A coupler as 'claimed in claim 3, wherein said portion of the blocking member
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`20
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`is shaped to present a concave curved surface to said first recess when the
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`blocking member is in the closed state.
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`5. A coupler as claimed in any preceding claim, wherein the blocking member is
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`arranged so that, in the blocking state, it lies in the path of the latching member
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`25
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`and that, upon movement of the latching member out of the latching state, the
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`latching member engages with the blocking member to retain it in the blocking
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`state.
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`6. A coupler as claimed in any preceding claim, wherein said portion of the
`
`3O
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`blocking member is provided by a jaw or recess.
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`7. A coupler as claimed in claim 6 when dependent on claim 2, wherein said jaw
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`or recess is located between said pivot point and a free end of the blocking
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`member.
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`8. A coupler as claimed in claim 8 when dependent on claim 5, wherein said free
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`end is engagable with the latching hook.
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`9. A coupler as claimed in any preceding claim, further including a lever movable
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`into and out