Coupler with attachment pin detection

Abstract

 A coupler (10) for coupling an attachment to an excavator, the coupler including a pin detection system for detecting the presence of a attachment pin (126) against a pin-engaging surface (154) in its pin-receiving recess (160), and means for indicating to an operator that the pin has been detected. The pin detection system comprises a contact member (152) that is movable between a rest state and a displaced state. The system allows the operator to determine that the pin is correctly located in the recess before activating a latch to hold the pin.

Description

Field of the Invention

[0001] The present invention relates to couplers for coupling an attachment, such as an excavating bucket, to the arm of an excavator or other machine. The invention relates particularly to couplers that are powered, especially hydraulically powered, and especially to couplers that are capable of accommodating attachments with different pin spacings.

Background to the Invention

[0002] Hydraulic couplers for quickly connecting and disconnecting construction attachments from excavating equipment are well known and are sometimes referred to as automatic couplers since they can be operated by an operator from with the cab of an excavator or other machine. International PCT patent application WO2011/035883 discloses an example of such a coupler.

[0003] When operating an automatic coupler the front attachment pin is normally visible to the operator can therefore visually check that the pin is in the correct position. However, the rear attachment pin is usually not visible to the operator. This can create a problem in that the rear pin of the attachment may not be located correctly on the bottom of the coupler body when the rear latch is closed. This can result in the rear latch passing the wrong side of the rear pin allowing the attachment to be free to swing on the front pin when the coupler orientation is changed.

[0004] It would be desirable therefore to provide a coupler in which the presence of the rear pin in the correct position within the rear aperture could be detected before closing the coupler.

Summary of the Invention

[0005] A first aspect of the invention provides a coupler for coupling an attachment to an excavator or other apparatus, the coupler comprising a body having a first and second spaced-apart recesses for receiving respective pins of said attachment; a latching member movable into and out of a latching state in which it is capable of retaining the respective attachment pin in said second recess; and actuating means for actuating said latching member into and out of said latching state, wherein the coupler further includes a pin detection system comprising means for detecting the presence of said attachment pin in said second recess, preferably against a pin-engaging surface; and means for indicating to an operator that said pin is detected in said second recess, preferably against said pin-engaging surface.

[0006] The preferred pin detection system comprises a movable contact member movable with respect to said body between a rest state and a displaced state, said detection means being configured to detect the presence of said pin by detecting if said movable contact member is in said displaced state.

[0007] In preferred embodiments, the movable contact member is caused, in use, to adopt said displaced state when said pin is engaged with said pin-engaging surface. Typically the movable contact member is movable by engagement, in use, with said pin when in said second recess. In the displaced state the contact member conveniently adopts a position in which it is held, in use, by the pin when the pin engages with said pin-receiving surface.

[0008] A second aspect of the invention provides a pin detection system for a coupler having a recess for receiving an attachment pin, the pin detection system comprising means for detecting the presence of said attachment pin in said recess; and means for indicating to an operator that said pin is detected in said recess. The recess preferably has a pin-engaging surface, said detection means being configured to detect the presence of said attachment pin against said pin-engaging surface. The indicating means is preferably configured to indicate to said operator that said pin is detected against said pin-engaging surface.

[0009] A third aspect of the invention provides a coupler having a pin detection system of the second aspect of the invention.

[0010] Preferred features are recited in the dependent claims.

[0011] Preferred embodiments enable an operator to detect that the pin is in the correct position on the bottom surface of its recess before operating the rear latch to prevent the risk of the rear latch missing the pin when the rear latch is closed.

[0012] Further advantageous aspects of the invention will be apparent to a skilled person upon review of the following description of a preferred embodiment and with reference to the accompanying drawings.

Brief Description of the Drawings

[0013] An embodiment of the invention is now described by way of example and with reference to the accompanying drawings in which like numerals are used to denote like parts and in which:

Figure 1 is a side view of a coupler;

Figure 2 is an interior side view of part of a coupler embodying the invention, showing a movable contact member in a rest state;

Figure 3 is an exterior side view of the coupler part of Figure 2 with the movable contact member in the rest state;

Figure 4 is an interior side view of the coupler part of Figure 2 showing the movable contact member in a displaced state;

Figure 5 is an exterior side view of the coupler part of Figure 2 with the movable contact member in the displaced state; and

Figure 6 is an alternative interior side view of the coupler part of Figure 2 showing the movable contact member in the displaced state.

Detailed Description of the Drawings

[0014] Referring now to Figure 1 of the drawings there is shown, generally indicated as 10, a coupler (or hitch) for connecting a tool, or other attachment such as a bucket or hammer, to an arm of an excavator (not shown), or other apparatus. The coupler 10 has a body 14 typically comprising two spaced-apart body parts typically in the form of side plates 15 (only one shown). The body 14 is shaped to define pin-receiving apertures 16, 17 by which the coupler 10 may be connected to the end of the arm. Typically, there are two spaced-apart apertures 16, 17 in each of the two side plates 15, the apertures in one side plate being aligned with the apertures in the other. When connected, the coupler 10 is able to pivot with respect to the arm about the axis of the apertures 16. Usually a hydraulic mechanism, or other power operated mechanism (not shown), is provided, typically in association with a mechanical linkage, to pivot the coupler 10 with respect to the arm. The mechanical linkage is usually connected between the arm and the aperture 17.

[0015] 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 26, 26', 26" of a bucket or other attachment. Normally, the recesses 20, 22 face in mutually perpendicular directions. The recess 20 is typically hook-like in shape and function. 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 pins 26' and 26" which are intended to represent a respective pin of a respective attachment, the attachment of pin 26' having narrower pin spacings than the attachment of pin 26". Clearly, the pins 26', 26" would not normally be present in the recess 22 simultaneously. The coupler can accommodate attachments having a range of pin spacings between a smallest spacing shown between pins 26 and 26' and a largest spacing shown between pins 26 and 26".

[0016] The coupler 10 also includes a first power-operated latching mechanism typically comprising a latching member, in the preferred form of a hook 30, and an actuator 32 typically in the form of a linear actuator such as 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. 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 at pivot 11 in any convenient manner and is pivotable about an axis that runs substantially perpendicular to the body 14/plates 15. The hook 30 is pivotable between an open, or non-latching, state and a latching state. 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 latching state, the latching hook 30 prevents the pins 26', 26" from being removed from the recess 22. The actual position of the latching member 30 in the latching state will depend on the pin spacing of the attachment being grabbed. For example, in Figure 1, the hook 30 is shown in the latching state with respect to pin 26', but in the open state with respect to pin 26". In alternative embodiments, the latching member may be slidably mounted on the body, or otherwise movable between the open state and the latching state(s), without necessarily being pivotable. Further, the latching member need not necessarily take the form of a hook. Conventionally, the recess 22 is said to be at the rear of the coupler and the latching member 30 may therefore be referred to as a rear latching member.

[0017] The coupler 10 may further include a blocking member, in the preferred form of a hook 40, for retaining an attachment pin 26 in the recess 20. Conventionally, the recess 20 is said to be at the front of the coupler and the blocking member 40 may therefore be referred to as a front blocking member. The blocking member 40 is pivotably mounted on the body 14 in any convenient manner, e.g. pin or bearing, at pivot point 42. The second hook 40 is pivotable about an axis substantially perpendicular to the side plates 15 between an open or non-blocking state and a blocking state (as shown Figure 1). In the non-blocking state, the hook 40 is clear of the recess 20 to the extent that it does not prevent the pin 26 from being removed from the recess 20, while in the blocking state, the hook 40 prevents the pin from being removed from the recess 20. In the preferred embodiment, the blocking member 40, preferably by means of a jaw 44, when in the blocking state, fully, or at least partly, closes the otherwise open mouth of the recess 20. In alternative embodiments, the blocking member 40 may be slidably mounted on the body, or otherwise movable between the open state and the blocking state(s), without necessarily being pivotable. Further, the blocking member 40 need not necessarily take the form of a hook.

[0018] Under normal operating conditions when the latching hook 30 is in its latching state, the pin 26 located in recess 20 is urged against the rear surface 21 of the recess 20 by the action of the latching hook 30 on the other pin 26', 26" located in the other recess 22 under the force exerted by the actuator 32 and/or the spring 90.

[0019] The coupler 10 may be referred to as an automatic coupler, or a power operated coupler, and is exemplary of the general type of coupler with which embodiments of the invention may be implemented but it will be understood that the invention is not limited to use with the specific coupler shown in Figure 1.

[0020] Referring now to Figures 2 to 6, there is described a pin detection system 150 embodying one aspect of the invention and a coupler 110 embodying another aspect of the invention. Figures 2 to 6 show respective side views of part of the coupler body 114, in particular the part that is normally referred to as the rear of the coupler 110. The illustrated body part includes the (rear) recess 122, which is shaped and dimensioned to receive an attachment pin 126 in more than one location within the recess 122. This allows attachments with different pin spacings to be engaged by the coupler 110, as can be seen by comparison of Figures 4 and 6. Other coupler parts, including the (rear) latching hook, are not shown for reasons of clarity. The views shown in Figures 2, 4 and 6 are interior views, i.e. from the inside of the coupler 110, while the views shown in Figure 3 and 5 are exterior views, i.e. from the outside of the coupler 110. In the illustrated embodiment, it is assumed that the coupler body 114 comprises spaced apart plates 115, only one of which is shown in Figures 2 to 6.

[0021] The pin detection system 150 comprises a movable contact member 152 coupled to the body 114 for movement with respect to the body 114 between a rest state (shown in Figures 2 and 3) and a displaced state (shown in Figures 4 and 6). The arrangement is such that, when an attachment pin 126 is correctly positioned in the recess 122 to allow it to be engaged correctly by the latching member associated with the recess 122, the pin 126 moves the contact member 152 from its rest state to its displaced state.

[0022] In typical embodiments, when the pin 126 is correctly positioned in the recess 122 it engages with a surface 160 that defines the recess 122, which is usually a surface of the body 114. Usually, the surface 160 is the bottom surface of the recess 122, i.e. the surface that runs between the sides of the recess 122.

[0023] The contact member 152 has a contact surface 154 for engaging with the pin 126. In the rest state the contact member 152 is positioned such that its contact surface 154 projects beyond the recess surface 160 (in a direction towards the mouth 123 of the recess 122) such that when the pin 126 enters the recess 122 it must engage the contact member 152 before it can engage the surface 160 of the recess 122. Once it engages the contact member 152, further movement of the pin 126 with respect to the body 114 causes the contact member 152 to move to its displaced state. In preferred embodiments, in the displaced state, the contact member 152 adopts a position in which the contact surface 154 does not project beyond the recess surface 160 (in a direction towards the mouth 123 of the recess 122) so that the pin 126 is able to engage the surface 160. When the pin 126 engages with the recess surface 122 its movement is halted and so too is the corresponding movement of the contact member 152. Conveniently therefore, in the displaced state the contact member 152 adopts a position in which it is held by the pin 126 when the pin 26 engages with the recess surface 122. Accordingly, when the pin 126 is correctly located in the recess 122 for the purposes of latching by the latching member (i.e. prior to being engaged by the latching member and advantageously prior to operation of the latching member to the latching state), the contact member 152 is in its displaced state. Typically, in the displaced state the contact surface 154 is flush with the recess surface 160.

[0024] In the illustrated embodiment, the contact member 152 has a single continuous contact surface 154, respective portions 154' 154" of which engage with the pin 126 depending on the pin spacing of the attachment, as can be appreciated by a comparison of Figures 4 and 6. The contact surface 154 typically extends along substantially the entire length of the bottom surface of the recess 122. Preferably, the surface 154 has a profile that substantially matches the profile of the bottom surface 160 of the recess 122. Alternatively, two or more separate respective contact surfaces may be provided, a respective one for each pin position within the recess 122 corresponding to an accommodated pin spacing. In any case, the preferred pin detection system 150 is capable of detecting the correct location of the pin in multiple locations in the recess 122 to accommodate attachments with different pin spacings. It will be understood that the foregoing description in relation to the interaction of the contact surface 154 with the pin 126, and the position of the contact surface 154 with respect to the recess surface 160 relates particularly to the respective contact surface 154 or contact surface portion 154', 154" that is associated with the relevant pin position. In the illustrated embodiment, the description applies to the entire contact surface 154 but in alternative embodiments this need not be the case. It is possible, for example, in an alternative embodiment that the contact surface 154 be shaped such that the portion 154" projects beyond the recess surface 160 when the pin 126 engages with the other portion 154' and holds the contact member 152 in its displaced state. Hence, the position of the contact member 152 in the displaced state may be different for different pin positions. It is preferred however, that the position of the contact member 152 in the displaced state is the same for all pin positions since this simplifies detection of the displaced state as is described in further detail below.

[0025] The contact member 152 may for example comprise a bar. The contact member 152 may be pivotably coupled to the body 14 for pivoting movement with respect to the body 114 between the rest and displaced states. In the illustrated embodiment, the contact member 152 is pivotably mounted on the body 114 at pivot point 156. The pivot point 156 is conveniently located at one side of the recess 122, the contact member 152 extending substantially across the bottom surface 160 of the recess 122, its exact position with respect to the recess 122 depending on its interaction or non-interaction with the pin 126.

[0026] In alternative embodiments (not illustrated), the contact member 152 may be coupled to the body 114 in any other convenient manner, for example for sliding or reciprocating movement with respect to the body 114 (e.g. up and down as viewed in the drawings) between the rest and displaced states.

[0027] Optionally, resilient biasing means may be coupled between the contact member 152 and the body 114 and be configured to urge the contact member 152 into its rest state. One or more springs (not illustrated) may be provided for this purpose, for example extending between the contact member 152 and the body and/or incorporated into the pivot 156. In use, the pin 126 urges the contact member 152 into its displaced state against the resilient bias.

[0028] Alternatively, or in addition, the coupling of the contact member 152 to the body 114 may be such that it tends to adopt the rest state under the influence of gravity in at least one, and preferably a plurality of, orientations of the coupler 110, typically including a horizontal orientation as depicted in the drawings.

[0029] Optionally, one or more stop members (not shown) may be provided, typically on the body 114, in the path of the contact member 152 to restrict movement of the contact member 152 in any one or both of its directions of movement between the rest and displaced states to ensure that the contact member 152 adopts a desired position when in the or each state.

[0030] The pin detection system 150 also includes detection means for detecting the state of the contact member 152, and in particular for detecting when the contact member 152 is in the displaced state. In the illustrated embodiment, the detection means comprises a detector in the form of an electro-mechanical switch 158. The switch 158 (or other detector(s)), which may be mounted on the body 114 in any convenient manner, is positioned such that it is activated by the contact member 152 when in its displaced state, or at least upon movement of the contact member 152 into the displaced state. In this example, the contact member 152 engages with the switch 158 to activate it mechanically. Alternatively, or in addition, the detection means may comprise one or more other detectors, for example optical and/or electromagnetic detectors.

[0031] The detection means is preferably co-operable with one or more indication device (not shown), for example an audio or visual indicator that may be located in the operator's cab or other convenient location, to cause the indication device(s) to be activated to indicate whether or not the contact member 152 is in its displaced state, i.e. whether or not the pin 126 is in the correct location. Once the operator determines that the pin is in the correct position, he can operate the latching member to hold it in place. It is preferred that the detection means and the indication device(s) together provide an indication that the pin is in the correct position so long as it remains in the correct position.

[0032] Pin detection may be performed by a switch, or other detector(s), being provided on the rear latching member and positioned to detect the presence of the pin when correctly clamped by the latch. However as the latch or attachment pin wears through use, the position of the rear latch and pin when clamped may vary by an extent that causes the switch/detector will not detect the rear pin even though it is securely clamped. In any event, it is beneficial to detect that the pin is in the correct position on the bottom surface 160 before operating the rear latch to prevent the risk of the rear latch missing the pin when the rear latch is closed. Therefore the preferred solution is to detect that the pin is against the bottom surface 160 before clamping, and preferably also to indicate that the pin is clamped correctly against the bottom surface 160 by the rear latch during use.

[0033] Alternatively still, one or more pin detectors, for example electromechanical switches, opto-electronic switches and/or electro-magnetic switches, may be provided at the recess 122 and configured to detect the presence of the pin 126 against the surface 160 for any relevant pin spacing(s). However in typical embodiments where it is necessary to accommodate a range of pin spacings, a plurality of such detectors would typically be required, which may be relatively difficult to implement and maintain.

[0034] As indicated above, the signal generated by detector 158 may be caused to activate a lamp and/or an audible signal for the operator. However, the signal could alternatively, or additionally, be utilised by an electronic and/or computer control system (not shown) that may be configured to, for example, ensure correct use of the coupler (e.g. by preventing operation of one or more aspects of the coupler (e.g. closing the rear latch) unless the pin is determined to be in the correct position), and which may incorporate a self testing/function testing of the operation of the pin detection system 150.

[0035] The invention is not limited to the embodiments described herein which may be modified or varied without departing from the scope of the invention.

Claims

1. A coupler for coupling an attachment to an excavator or other apparatus, the coupler comprising a body having a first and second spaced-apart recesses for receiving respective pins of said attachment; a latching member movable into and out of a latching state in which it is capable of retaining the respective attachment pin in said second recess; and actuating means for actuating said latching member into and out of said latching state, wherein the coupler further includes a pin detection system comprising means for detecting the presence of said attachment pin in said second recess; and means for indicating to an operator that said pin is detected in said second recess.

2. A coupler as claimed in claim 1, wherein said second recess has a pin-engaging surface, said detection means being configured to detect the presence of said attachment pin against said pin-engaging surface and wherein, preferably, said indicating means is configured to indicate to said operator that said pin is detected against said pin-engaging surface, and wherein said pin-engaging surface preferably comprises a bottom surface of said second recess.

3. A coupler as claimed in claim 1 or 2, wherein said pin detection system comprises a movable contact member movable with respect to said body between a rest state and a displaced state, said detection means being configured to detect the presence of said pin by detecting if said movable contact member is in said displaced state, and wherein, preferably, said movable contact member is caused, in use, to adopt said displaced state when said pin is correctly located in said second recess.

4. A coupler as claimed in claim 3, wherein said contact member has a contact surface for engaging with said pin, and wherein in the rest state the contact member is positioned such that said contact surface projects beyond said pin-engaging surface in a direction towards the mouth of the second recess, and wherein, preferably, in the displaced state the contact member adopts a position in which the contact surface does not project beyond said pin-engaging surface in a direction towards the mouth of the second recess.

5. A coupler as claimed in claim 3 or 4, wherein in the displaced state the contact surface is flush with said pin-receiving surface.

6. A coupler as claimed in any one of claims 3 to 5, wherein resilient biasing means is coupled between the contact member and the body and is configured to urge the contact member into its rest state.

7. A coupler as claimed in any one of claims 4 to 6, wherein said contact surface has a profile that substantially matches the profile of said pin-engaging surface.

8. A coupler as claimed in any one of claims 4 to 7, wherein said contact surface extends along substantially the entire length of said pin-engaging surface.

9. A coupler as claimed in any preceding claim, wherein said detecting means comprises one or more detectors, for example electro-mechanical, opto-electronic and/or electromagnetic switches and is preferably configured to detect when said contact member is in said displaced state.

10. A coupler as claimed in any one of claims 3 to 9, wherein the contact member comprises a bar, preferably being shaped and dimensioned to extend substantially across said second recess.

11. A coupler as claimed in any one of claims 3 to 10, wherein said contact member is pivotably coupled to the body for pivoting movement with respect to the body between the rest and displaced states.

12. A coupler as claimed in any preceding claim, wherein said indicating means comprises one or more audio and/or visual indicator.

13. A coupler as claimed in any preceding claim, wherein said pin detection system is cooperable with a coupler control system, the coupler control system being configured to prevent or restrict operation of said coupler unless said pin detection system indicates that said pin is correctly located in said second recess.

14. A coupler as claimed in any preceding claim, wherein said second recess has a width that is greater than the width of said pin in order to accommodate attachments having different pin spacings, and wherein said pin detection system is configured to detect the presence of said pin in any one of multiple locations in said second recess corresponding to said different pin spacings, and wherein, preferably, the contact member has a single continuous contact surface respective portions of which engage in use with the pin depending on the pin spacing of the attachment, or has two or more contact surfaces, a respective one for each pin position with the second recess corresponding to a respective attachment pin spacing.

15. A coupler as claimed in any preceding claim, wherein said pin detection system detects, in use, the presence of said attachment pin in said second recess prior to operation of said latching member to said latching state, and wherein said indicating means indicates to said operator, in use, that said pin is detected in said second recess prior to operation of said latching member to said latching state.

Drawing