Patent Publication Number: US-2023160172-A1

Title: Quick coupler automatic locking mechanism and method

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to attachments and work tools for a work machine and, more specifically, to a quick coupler having an automatic locking mechanism. 
     BACKGROUND 
     Quick couplers are intermediate attachments for work machines which enable the machine to efficiently switch between different work tools. A quick coupler may be directly connected to an arm of a work machine, which may be an excavator, backhoe, front-end loader, and the like; and the coupler may be movable and actuated by one or more hydraulic cylinders of the work machine. A work tool, such as a bucket, hammer, auger, grapple, and many others, may be connected to the quick coupler through a locking mechanism of the coupler. The work tool may then be maneuvered by the work machine and/or may have the same range of motion as if it were directly connected to the arm. Advantageously, attachment and detachment of the work tool onto the quick coupler may be much quicker and easier than attachment or detachment onto the work machine directly. Moreover, quick couplers are capable of interfacing with a wide range of work tools, even those from different manufacturers. 
     A pin grabber coupler is a type of quick coupler configured to interoperate with pin-on work tools. Specifically, one or more tool pins of the work tool may be respectively locked into one or more locking zones of the pin grabber coupler. In many prior art designs, the locking zones and the locking mechanism therein are controlled by a single actuator, a configuration which, while simple and efficient, may have disadvantages. 
     For example, many prior art couplers require an operator of the work machine to perform a precise series of actions to safely attach the tool to the coupler. First, to initially ‘grab’ the tool, the tool may need to be situated within a specific location with respect to the work machine. If the work tool is situated too far away, too high up, or with an improper angle with respect to its center of gravity and/or tool pin orientation, the operator may need to first reposition either the tool or the machine. Furthermore, according to some prior art designs, the work tool may not be fully secured during the period after which it is ‘grabbed’ but before the locking mechanism is fully locked, further stressing the need for delicate operator control. Accordingly, such single-actuator couplers may create potentially hazardous situations and allow little room for error on the part of the work machine&#39;s operator. 
     Other pin grabber couplers within the prior art have attempted to improve the above drawbacks by increasing a number of locking mechanisms and a number of locking actuators provided by the coupler. In such designs, the coupler may initially and independently lock onto a first tool pin of the work tool, thereby improving an ease and a security of the coupling maneuvers thereafter. One such example is disclosed by U.S. Pat. No. 10,323,379, invented by Thomas Friedrich and assigned to Kinshofer GMBH. Specifically, Friedrich teaches a quick coupler for a work machine, the coupler comprising a coupling mount and a locking mount configured to receive a first locking part and a second locking part, respectively, of a tool attachment. A securing element is associated with the coupling mount and may be independently actuated by a securing element adjustment actuator. Further, a locking element is associated with the locking mount and may be independently actuated by a locking element adjustment actuator. Friedrich may thus enable either the first locking part of the second locking part of the work tool to be independently attached to the coupler. 
     Unfortunately, Friedrich also requires additional actuators and associated hydraulic infrastructure to implement independent actuation of the securing element and the locking element, thereby increasing a cost and complexity of their design. In contrast, the single-actuator couplers of the prior art are much simpler in design and manufacture, but demand more complex maneuvers on the part of the work machine operator. 
     Accordingly, there remains a need in the art for a single-actuator quick coupler capable of independently and automatically locking onto a single tool pin of the work tool, thereby simplifying and safeguarding the coupling without unduly increasing the coupler&#39;s complexity and cost. 
     SUMMARY OF THE DISCLOSURE 
     According to a first aspect of the present disclosure, a quick coupler is disclosed. The quick coupler comprises a frame including: a notch defining a chamber and having a mouth, the notch configured to receive a first tool pin; and a hook defining a concavity and having an entrance, the hook configured to receive a second tool pin. The quick coupler further comprises a cylinder including a cap end and a rod end; a primary blocking member configured to lock and unlock the first tool pin within the notch, wherein the primary blocking member is attached to one of the cap end and the rod end of the cylinder; a secondary blocking member configured to lock and unlock the second tool pin within the hook, wherein the secondary blocking member is attached to the other of the cap end and the rod end of the cylinder; a biasing member biasing the secondary blocking member toward a locked position; and a controller. The quick coupler can automatically lock the second tool pin within the hook without actuating the cylinder. 
     According to a second aspect of the present disclosure, a method of coupling a work tool to a quick coupler is disclosed. The method comprises first activating an AUTOMATIC LOCKING state of the coupler. The method further comprises maneuvering the coupler to automatically lock a second tool pin of the work tool within a hook of the coupler without actuation of a cylinder of the coupler, such that: the second tool pin forces a secondary blocking member to move from a locked position to an unlocked position; the second tool pin enters the hook; and the secondary blocking member returns to the locked position. The method further comprises the first tool pin entering a notch of the coupler; and activating a LOCKED state of the coupler. 
     According to a third aspect of the present disclosure, a method of decoupling a work tool from a quick coupler is disclosed. The method comprises: activating an AUTOMATIC LOCKING state of the coupler. The method further comprises maneuvering the work tool to rest on a surface, during which, without actuating a cylinder of the coupler: a first tool pin exits a notch of the coupler; and a second tool pin is prevented from exiting a hook of the coupler. The method further comprises activating an UNLOCKED state of the coupler; and fully separating the coupler from the work tool. 
     These and other aspects and features of the present disclosure will be more readily understood after reading the following description in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an illustration of an exemplary work machine employed in conjunction with a quick coupler according to an embodiment of the present disclosure. 
         FIG.  2    is a diagram of a quick coupler in an UNLOCKED state according to another embodiment of the present disclosure. 
         FIG.  3    is a schematic of a hydraulic assembly of the quick coupler according to an embodiment of the present disclosure. 
         FIG.  4    is a schematic of a hydraulic assembly according to another embodiment of the present disclosure. 
         FIG.  5    is a schematic of a hydraulic assembly according to another embodiment of the present disclosure. 
         FIG.  6    is a schematic of a hydraulic assembly according to another embodiment of the present disclosure. 
         FIG.  7    is a flowchart outlining a method of coupling a work tool to a quick coupler according to an embodiment of the present disclosure. 
         FIG.  8    is a flowchart outlining a method of decoupling a work tool from a quick coupler according to another an embodiment of the present disclosure. 
         FIG.  9 A- 9 E  diagram one or more operations of the quick coupler during the method outlined in  FIG.  7     
         FIGS.  10 A- 10 D  diagram one or more operations of the hydraulic assembly during the method outlined in  FIG.  7   . 
         FIGS.  11 A- 11 C  diagram one or more operations of the quick coupler during the method outlined in  FIG.  8   . 
         FIGS.  12 A- 12 D  diagram one or more operations of the hydraulic assembly during the method outlined in  FIG.  8   . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings and with specific reference to  FIG.  1   , a diagram of a work machine is generally referred to by a reference numeral  1 . While the work machine  1  is depicted as an excavator, it may alternatively be a mini-excavator, backhoe, front loader, tractor loader, or comparable machine employed in construction, mining, earth moving, and/or agricultural applications. The work machine  1  may specifically comprise a frame  11 , a prime mover  12  or engine supported by the frame  11 , and a locomotive device  13  supporting the frame  11  and being operatively driven by the prime mover  12 . 
     The work machine  1  may further include an implement arm  20 , including one or more of a boom, stick, dipper, and other possible appendages. The implement arm  20  may be operatively controlled by a hydraulic power system  30 , e.g. through one or more hydraulic actuators or cylinders. In the embodiment shown, the implement arm  20  may specifically include a boom  21  pivotably mounted at a proximal end to the frame  11  and operable by boom actuators  31 , which raise or lower the boom  21  with respect to the frame  11 . The implement arm  20  may further include a stick  22  pivotably connected at a proximal end to a distal end of the boom  21  and operable by stick actuators  32 , which pivot the stick  22  with respect to the boom  21 . 
     With continued reference to  FIG.  1   , a quick coupler  400  may be connected to a distal end of the stick  22  and may be operable by one or more tool actuator  33 , which pivot the coupler  400  with respect to the stick  22 . More specifically, the coupler  400  may be pivotably connected to the stick  22  by a first stick pin  221 ; and the tool actuator  33  may be operatively connected to the coupler  400  by a power link  23  coupled to a second stick pin  222 . In some embodiments, the quick coupler  400  may specifically be a pin grabber coupler  400   a , configured to associate with a pin-on work tool. 
     With continued reference to  FIG.  1   , the quick coupler  400  may be configured to receive a work tool  500 , which may be operatively maneuvered by the implement arm  20  and the hydraulic power system  30  via the coupler  400 . In some embodiments, the work tool  500  may specifically be a pin-on work tool  500   a , configured to associate with the pin grabber coupler  400   a . And while the work tool  500  is illustrated as a bucket, this is by example only, and the tool  500  may alternatively be a grapple, hammer, compactor, claw, blade, or one of many other tools and attachments common to the art. Furthermore, in some embodiments, other configurations for the implement arm  20  and its appendages, and other methods of connecting and operating the quick coupler  400 , are also possible without departing from a scope of the present disclosure. 
     Turning now to  FIG.  2   , a diagram of the quick coupler  400  is provided in greater detail. The quick coupler  400  may comprise a frame  410 , a cylinder  420 , a primary blocking member  430 , a secondary blocking member  440 , a biasing member  450 , and a controller (not shown). In some embodiments, the coupler  400  may further comprise a hydraulic assembly  600 . The frame  410  may include a pair of ports  401 , a notch  411 , and a hook  412 . The ports  401  may be configured to receive the first stick pin  221  and the second stick pin  222  of the work machine  1 . The notch  411  may have a mouth  4111  and may define a chamber  4112 . Further, the notch  411  may be configured to receive a first tool pin  510  of the work tool  500 . The hook  412  may have an entrance  4121  and define a concavity  4122 . Further, the hook may be configured to receive a second tool pin  520  of the work tool  500 . 
     The quick coupler  400  may further comprise a cylinder  420  having a cap end  421  and a rod end  422 . A primary blocking member  430  may be attached to either the cap end  421  or the rod end  422  of the cylinder  420 ; and may be configured to lock and unlock the first tool pin  510  within the notch  411  of the frame  410 . A secondary blocking member  440  may be attached to the other of the cap end  421  and the rod end  422  (i.e. the end not attached to the primary blocking member  430 ); and may be configured to lock and unlock the second tool pin  520  within the hook  412  of the frame  410 . While the primary blocking member  430  is shown to be attached to the rod end  422  and the secondary blocking member  440  is shown to be attached to the cap end  421 , in other embodiments these attachments can be reversed, i.e. the cylinder  420  can be reversed. 
     In an embodiment, the primary blocking member  430  may specifically include a wedge  4301  and a tab  4302 ; and may be rotatably attached to an end of the cylinder  420 . In the exemplary embodiment shown in  FIG.  2   , the wedge  4301  may be rotatably attached to the rod end  422  about a rotation axis W1; and the tab  4302  may be configured to lock and unlock the first tool pin  510  within the notch  411 . However, it should be understood that other configurations for the primary blocking member  430  are also possible. Without limitation, the primary blocking member  430  may alternatively or additionally include a rocker, a hook, a catch, and other possible locking mechanisms; the primary blocking member  430  may be connected to the cap end  421  of the cylinder  420  instead; and/or the primary blocking member  430  may include connections with the frame  410 . 
     In an embodiment, the secondary blocking member  440  may specifically include a rocker  4401  and a secondary lock  4402 ; and may be rotatably attached to the other end of the cylinder  420 . In the exemplary embodiment shown in  FIG.  2   , the rocker  4401  may be rotatably attached to the cap end  421  about a rotation axis R1 and pivotably attached to the frame  410  about a pivot axis R2. In the same or other embodiments, the secondary lock  4402  may be rotatably attached to the rocker  4401  about a rotation axis S1 and pivotably attached to the frame  410  about a pivot axis S2; and the secondary lock  4402  may be configured to lock and unlock the second tool pin  520  within the hook  412 . More specifically, a pivoting of the secondary lock  4402  may move the secondary blocking member  440  between a locked and unlocked position (and vice versa). However, it should be understood that other configurations for the secondary blocking member  440  are also possible. Without limitation, the secondary blocking member  440  may alternatively or additionally include a wedge, a tab, a hook, a catch, and other possible locking mechanisms; the secondary blocking member  440  may be connected to the rod end  422  of the cylinder  420  instead; and/or the secondary blocking member  440  may include alternative connections with the frame  410 . 
     With continued reference to  FIG.  2   , the biasing member  450  may bias the secondary blocking member  440  toward the locked position. In the exemplary embodiment shown, the biasing member  450  may be a spring  450   a  mounted to the frame  410  and configured to convey a biasing force on the rocker  4401 , although other biasing devices and designs are also possible. 
     The quick coupler  400  may be capable of operating in one of at least three states, including a LOCKED state, an UNLOCKED state, and an AUTOMATIC LOCKING state. Each state will now be discussed in greater detail, and may be best understood with reference to  FIG.  9 E ,  FIG.  9 A , and  FIGS.  9 B- 9 D , respectively. 
     During the LOCKED state, as best depicted in  FIG.  9 E , the cylinder  420  may be partially or fully extended. Accordingly, the primary blocking member  430  may be in a locked position, and may prevent the first tool pin  510  from entering or exiting the notch  411 . In the exemplary embodiment shown, the primary blocking member  430  may include the wedge  4301  and the tab  4302  connected to the rod end  422 . Accordingly, the cylinder  420  may be extended such that the tab  4302  blocks the mouth  4111  of the notch  411 . Likewise, during the LOCKED state, the secondary blocking member  440  may be in the locked position, and may prevent the second tool pin  520  from entering or exiting the hook  412 . In the exemplary embodiment shown, the secondary blocking member  440  may include the rocker  4401  and the secondary lock  4402  connected to the cap end  421 . Accordingly, the cylinder  420  may be extended such that the rocker  4401  is pivoted counterclockwise (CCW) about the pivot axis R2, and the secondary lock  4402  is pivoted clockwise (CW) about the pivot axis S2 to block the entrance  4121  of the hook  412 . It should be understood that the directions of rotation (i.e. CW, CCW) are provided for clarity only, are made with respect to the reference frames depicted in  FIGS.  9 A- 9 E  only, and that other directions and rotations are possible in other reference frames. 
     During the UNLOCKED state, as best depicted in  FIG.  9 A , the cylinder  420  may be partially or fully retracted. Accordingly, the primary blocking member  430  may be in an unlocked position, and may allow the first tool pin  510  to freely enter or exit the notch  411 . In the exemplary embodiment shown, the primary blocking member  430  may include the wedge  4301  and the tab  4302  connected to the rod end  422 . Accordingly, the cylinder  420  may be retracted such that the tab  4302  unblocks the mouth  4111  of the notch  411 . Likewise, during the UNLOCKED state, the secondary blocking member  440  may be in an unlocked position, and may allow the second tool pin  520  to freely enter or exit the hook  412 . In the exemplary embodiment shown, the secondary blocking member  440  may include the rocker  4401  and the secondary lock  4402  connected to the cap end  421 . Accordingly, the cylinder  420  may be retracted such that the rocker  4401  is pivoted CW about the pivot axis R2, and the secondary lock  4402  is pivoted CCW about the pivot axis S2 to unblock the entrance  4121  of the hook  412 . 
     Before describing the AUTOMATIC LOCKING state, the present disclosure may benefit from a brief discussion of the hydraulic assembly  600 . In various embodiments, the hydraulic assembly  600  may be placed within the coupler  400 , may be partially located within the coupler  400  (as seen in  FIG.  2   ), or may be located external to the coupler  400 , depending on specific applicational requirements. With reference now to  FIG.  3   , the hydraulic assembly  600  may specifically include a directional control assembly  610  controllably connected to one or more of the cap end  421 , the rod end  422 , a pump  601 , and a tank  602 . The directional control assembly  610  may be capable of operating in a second position corresponding to and operatively enabling the LOCKED state of the coupler  400 , a third position corresponding to and operatively enabling the UNLOCKED state of the coupler  400 , and a float position corresponding to and operatively enabling the AUTOMATIC LOCKING state of the coupler. In the exemplary embodiment shown, the directional control assembly  610  may include a 4-way 3-position directional control valve  610   a . And in the same or other embodiments, the directional control valve  610   a  may be solenoid-controlled. In other embodiments, the directional control assembly  610  may be alternatively configured, such as with a 4-way 4-position directional control valve, a 4-way 5-position directional control valve, two 4-way 2-position directional control valves, and yet other possible designs without departing from a scope of the present disclosure. 
     During the LOCKED state of the coupler  400 , the directional control assembly  610  may be operating in the second position. Accordingly, the pump  601  may be connected to the cap end  421  and the tank  602  may be connected to the rod end  422 , thereby effecting an extension of the cylinder  420 . 
     During the UNLOCKED state of the coupler  400 , the directional control assembly  610  may be operating in the third position. Accordingly, the pump  601  may be connected to the rod end  422  and the tank  602  may be connected to the cap end  421 , thereby effecting a retraction of the cylinder  420 . 
     During the AUTOMATIC LOCKING state of the coupler  400 , as best depicted in  FIGS.  9 B- 9 D , the directional control assembly  610  may operate in the float position seen in  FIG.  3   . Accordingly, the directional control assembly  610  may operatively connect the cap end  421 , the rod end  422 , and the tank  602 , thereby removing most if not all hydraulic pressure imparted on the cylinder  420 . Under such conditions, and barring external forces, the cylinder  420  may remain in a position similar to its position before the AUTOMATIC LOCKING state was activated; and the primary blocking member  430  and the secondary blocking member  440  may likewise remain in their prior positions. 
     However, during the AUTOMATIC LOCKING state, the biasing member  450  biases the secondary blocking member  440 , such that the secondary blocking member  440  is moved to the locked position. It may be understood that, while the biasing member  450  may provide a biasing force in all operating states of the coupler  400 , its force may be negated by hydraulic pressures during the LOCKED and UNLOCKED states. In an embodiment, the biasing member  450  may be a spring  450   a  and the secondary blocking member may include the rocker  4401  and the secondary lock  4402 . Accordingly, the spring  450   a  may bias the rocker  4401  to rotate CCW about the pivot axis R2, such that the secondary lock  4402  is pivoted CW about the pivot axis S2 to block the entrance  4121  of the hook  412 . 
     Furthermore, during the AUTOMATIC LOCKING state, the secondary blocking member  440  may allow the second tool pin  520  to enter the hook  412  if the biasing force of the biasing member  450  is overcome. In other words, an operator may force the secondary blocking member  440  open by moving the coupler  400  to forcibly receive the second tool pin  520  within the hook  412 . Once the second tool pin  520  enters the hook  412 , the secondary blocking member  440  may return to the locked position, and may prevent the second tool pin  520  from exiting the hook  412 . In other words, during the AUTOMATIC LOCKING state, the coupler  400  may be capable of automatically locking the second tool pin  520  within the hook  412  without any actuation of the cylinder  420 . In some embodiments, the secondary blocking member  440  may be configured such that no amount of force in an exiting direction can move the secondary blocking member  440  into the unlocked position. 
     During the AUTOMATIC LOCKING state, the primary blocking member  430  may retain its position prior to the coupler  400  entering the AUTOMATIC LOCKING state. For example, if the previous state was the UNLOCKED state, the primary blocking member  430  may remain in an unlocked position. In some embodiments, the UNLOCKED state may always precede the AUTOMATIC LOCKING state, such that the primary blocking member  430  is always in the unlocked position during the AUTOMATIC LOCKING state. And in yet other embodiments, the primary blocking member  430  may be in the unlocked position during the AUTOMATIC LOCKING state, regardless of a prior state of the coupler  400 . 
     With reference now to  FIGS.  3 - 6   , several embodiments of the hydraulic assembly  600  will now be described in greater detail. As previously discussed, the assembly  600  may be partially or fully located inside the coupler  400 . For the purposes of this disclosure, the terms ‘downstream’ and ‘upstream’ may refer to a directionality of each component, i.e. a check valve may only allow fluid flow in the ‘downstream’ direction. 
     As seen in  FIG.  3   , the hydraulic assembly  600  may comprise the directional control assembly  610  operatively connected to the cap end  421 , the rod end  422 , the pump  601 , and the tank  602 . In an embodiment, the directional control assembly  610  may specifically include the 4-way 3-position directional control valve  610   a . In addition, the hydraulic assembly  600  may comprise a first check valve  620 , which may be a spring check valve, located downstream of the pump  601  and upstream of the directional control assembly  610 . In an embodiment, a flow control element  630 , which may be a fixed orifice, may be located between the first check valve  620  and upstream of the directional control assembly  610 . The assembly  600  may further comprise a first pilot-operated (PO) check valve  640  downstream of the directional control assembly  610  and upstream of the cap end  421 . In some embodiments, the hydraulic assembly  600  shown in  FIG.  3    may be adequate to implement automatic locking mechanisms for a pin grabber coupler styled quick coupler. 
     Turning now to  FIG.  4   , another embodiment of the hydraulic assembly  600  is shown. Specifically, the hydraulic assembly  600  may comprise at least the elements shown in  FIG.  3   , and may further comprise a second PO check valve  650 , located downstream of the rod end  422 , upstream of the directional control assembly  610 , and receiving a pilot pressure from the cap end  421 . The assembly  600  may further comprise a pressure relief valve  680  located downstream of the rod end  422 , upstream of the directional control assembly  610 , and connected in parallel with the second PO check valve  650 . In some embodiments, the second PO check valve  650  may a prevent momentary bleeding of pressure from the rod end  422  of the cylinder  420  during transitions of the directional control assembly  610 . And in some embodiments, the hydraulic assembly  600  shown in  FIG.  4    may be adequate to implement automatic locking mechanisms for a pin grabber coupler styled quick coupler. 
     Turning now to  FIG.  5   , another embodiment of the hydraulic assembly  600  is shown. Specifically, the hydraulic assembly  600  may comprise at least the elements shown in  FIG.  3   . Moreover, the assembly  600  may comprise a pressure reducing valve  660  downstream of the directional control assembly  610  and upstream of the rod end  422 ; and and a second check valve  670 , which may be a spring check valve, downstream of the rod end  422 , upstream of the directional control assembly  610 , and connected in parallel with the pressure reducing valve  660 . In some embodiments, the hydraulic assembly  600  shown in  FIG.  5    may be adequate to implement an automatic locking mechanism for any style of quick coupler. 
     Turning now to  FIG.  6   , yet another possible embodiment of the hydraulic assembly  600  is provided. The assembly  600  may comprise at least the elements shown in  FIG.  5   . Moreover, the assembly  600  may further comprise the second PO check valve  650  located downstream of the pressure reducing valve  660  and upstream of the rod end  422 . Furthermore, the pressure relief valve  680  may be located downstream of the rod end  422 , upstream of the second check valve  670 , and connected in parallel with the second PO check valve  650 . In some embodiments, the hydraulic assembly  600  shown in  FIG.  6    may be adequate to implement an automatic locking mechanism for any style of quick coupler. 
     In some embodiments, the pressure relief valve  680  may prevent the primary blocking member  430  from inadvertently drifting when the directional control assembly  610  is operating in the float position, i.e. when the coupler  400  is in the AUTOMATIC LOCKING state. More specifically, when transitioning between the LOCKED state and the AUTOMATIC LOCKING state, the pressure relief valve  680  may be configured to allow a pressure release of the rod end  422  in order to prevent the primary blocking member  430  from drifting into the locked position, but nonetheless allowing the biasing member  450  to bias the secondary blocking member  440  into the locked position. 
     In other embodiments, when transitioning between the LOCKED state and the AUTOMATIC LOCKING state, the primary blocking member  430  may be held in a prior position through a force of friction only, such as in the exemplary embodiments shown in  FIGS.  3  and  5   . And in yet other embodiments, the primary blocking member  430  may be permitted to drift slightly away from a prior position during the AUTOMATIC LOCKING state, so long as the notch  411  remains unblocked. 
     The hydraulic assembly  600  may be managed by a controller (not shown), the controller having a processor and a memory in the form of a non-transitory computer-readable medium. The controller may be, without restriction, a gateway computer, a field-programmable gate array (FPGA), an application-specific integrated circuit ASIC), an engine control unit (ECU) of the work machine  1 , or comparable computing device capable of receiving inputs and outputting commands to the hydraulic assembly  600 . The controller may be in operative communication with an operator of the work machine  1 , and may receive commands from the operator through any number of input devices  19  of the work machine  1 , such as but not limited to buttons, dials, switches, pedals, knobs, touchscreens, and the like. 
     The controller may operatively control the state of the coupler  400  (e.g. LOCKED, UNLOCKED, or AUTOMATIC LOCKING) according to inputs received from the operator and/or from the input devices  19 . In one embodiment, the input devices  19  may include a coupler switch  19   a . And in the same or other embodiments, the coupler switch  19   a  may include one or more of the following settings: ‘temporary unlock’, ‘permanent unlock’, ‘permanent lock’, and ‘automatic locking’, each of which will be discussed in greater detail below. 
     By employing the disclosed designs, a quick coupler may be improved with an automatic locking mechanism without requiring additional actuators, thereby improving an ease and security of a tool coupling process without increasing underlying costs. 
     INDUSTRIAL APPLICATION 
     The present disclosure may find industrial applicability in any number of work machines which employ quick couplers in order to switch between different tool attachments. While the work machine is depicted as an excavator in certain embodiments, the present disclosure may likewise apply to mini-excavators, backhoes, front-end loaders, forest machines, material handlers, and other, comparable vehicles and machinery employed in construction, mining, earth moving, and/or agricultural applications. Furthermore, while the work tool is depicted as a bucket in certain embodiments, the quick coupler may be configured to attach to one of any number of work tools, including but not limited to augers, blades, bale grabs, compactors, forks, hammers, grapples, pulverizers, rippers, and many others. Moreover, the coupler may be capable of interlocking with work machines and with work tools from different manufacturers and product lines. 
     By employing the designs disclosed herein, a quick coupler may automatically lock onto a single tool pin of a work tool, decreasing an overall difficulty and improving an overall safety of the tool attachment process. More specifically, the automatic locking mechanism of the coupler may enable an operator to ‘grab’ a work tool situated at closer and/or further distances with respect to the work machine, situated at lower and/or higher elevations with respect to the work machine, and situated in a greater range of angles with respect to the tool&#39;s center of gravity or tool pin orientation. Once the first (or second) tool pin is secured, the automatic locking feature may decrease if not eliminate the possibility of detachment between the coupler and the work tool during the subsequent coupling maneuvers, making the process easier and safer for both equipment and personnel. Furthermore, when decoupling the work tool from the quick coupler, the same advantages with regard to operator ease, procedure safety, and machine range of motion may be afforded. 
     The above improvements may be obtained without increasing a complexity or cost of the coupler. More specifically, the quick coupler of the present disclosure can enable automatic locking and, indeed, independent locking of the second tool pin, with only a single hydraulic cylinder controlling both locking zones, i.e. the notch and the hook. Advantageously, in some embodiments, an existing quick coupler may be retrofitted with the disclosed designs through minor modifications to its hydraulic assembly and/or modifications to a logic controlling the hydraulic assembly. 
     Turning now to  FIG.  7   , a method of coupling a work tool to a quick coupler is generally referred to by a reference numeral  700 . The method  700  may best understood in consideration of  FIGS.  9 A- 9 E  and  FIGS.  10 A- 10 D , the former depicting an operation of the coupler and the latter illustrating an operation of the hydraulic assembly throughout the coupling process. The method  700  may comprise activating an AUTOMATIC LOCKING state of the coupler (block  701 ), maneuvering the coupler to automatically lock a second tool pin within a hook of the coupler (block  702 ), the first tool pin entering a notch of the coupler (block  703 ), and activating a LOCKED state of the coupler (block  704 ), each step of which will be discussed in greater detail below. 
     The method may comprise first activating an AUTOMATIC LOCKING state of the coupler (block  701 ). In some embodiments, the AUTOMATIC LOCKING state may be activated by operating a coupler switch, which may be located on the work machine  1  or located remotely. For example, the AUTOMATIC LOCKING state may be activated by switching the coupler switch to an ‘automatic locking’ setting. 
     In other embodiments, the AUTOMATIC LOCKING state may be activated if/when the operator executes a specific order of actions. For example, the AUTOMATIC LOCKING state may be activated if and/or only if the operator first curls the coupler, and switches the coupler switch to a ‘temporary unlock’ setting, thereby first activating an UNLOCKED state of the coupler. In such embodiments, an onboard computer of the work machine, the controller of the coupler, or another system may detect the order of actions, which effectively command the coupler to activate the AUTOMATIC LOCKING state. In other embodiments, alternative switches, inputs, and series of actions may be programmed to activate the AUTOMATIC LOCKING state, where no limitation is intended herein. Finally, in the same or other embodiments, the coupler may always enter the UNLOCKED state before activating the AUTOMATIC LOCKING state. 
     During the UNLOCKED state, a directional control assembly may operate in a third position operatively connecting a rod end of the cylinder to a pump and a cap end of the cylinder to a tank, as best seen in  FIG.  10 A . The cylinder may retract such that both the primary blocking member and the secondary blocking member move to an unlocked position, as best seen in  FIG.  9 A . At the same time, a biasing member may bias the secondary blocking member toward a locked position. However, when the coupler is in the UNLOCKED state, the force applied by the biasing member may be negated by the cylinder&#39;s hydraulic pressure. 
     After a predetermined period in the UNLOCKED state, such as a time require to fully retract the cylinder, the coupler may enter the AUTOMATIC LOCKING state. Accordingly, the directional control assembly may operate in a float position operatively connecting the rod end and the cap end to the tank, as best seen in  FIG.  10 B . This may reduce hydraulic pressure to the cylinder, such that the biasing force of the spring is no longer negated. The secondary blocking member may thus be biased by the biasing member to move to the locked position, while the primary blocking member may remain in the unlocked position, as best seen in  FIG.  9 B . 
     Returning now to  FIG.  7   , the method  700  may comprise an operator maneuvering the coupler to automatically lock the second tool pin within the hook (block  702 ). More specifically, the coupler may be maneuvered such that second tool pin forces the secondary blocking member to move from the locked position into the unlocked position; such that the second tool pin enters the hook; and such that the secondary blocking member returns to the locked position. In an exemplary embodiment seen in  FIG.  9 C , the second tool pin may exert an entry force against a secondary lock rotatably attached to a rocker, and may rotate the secondary lock to force the secondary blocking member from the locked position to the unlocked position. Once the second tool pin enters the hook, the biasing member may return the secondary blocking member to the locked position. In some embodiments, the coupler may be configured such that no amount of exit force exerted by the second tool pin can move the secondary blocking member from the locked state into the unlocked state. Furthermore, throughout block  702  of the method  700 , the directional control assembly may continue to operate in the float position, as seen in FIG.  10 B. Accordingly, automatically locking the second tool pin within the hook may occur without any actuation of the cylinder. 
     With reference again to  FIG.  7   , the method  700  may further comprise the first tool pin entering a notch of the coupler (block  703 ). In some embodiments, this step may entail an operator lifting the work tool off a surface and curling the coupler, i.e. pivoting the coupler with respect to an implement arm of the work machine. As the work tool is raised from the surface, it may lose any normal forces exerted by the surface and may hang from the hook of the coupler by the second tool pin. Furthermore, as the coupler is curled, the coupler may rotate with respect to the work tool about a rotation axis T1 of the second tool pin, while an orientation of the work tool may stay relatively unchanged due to gravity. As best seen in  FIG.  9 D , the coupler may be rotated with respect to the work tool such that the first tool pin freely enters the notch. Moreover, throughout block  703 , the directional control assembly may continue to operate in the float position, as seen in  FIG.  10 C , again without any additional actuation of the cylinder. 
     Returning once again to  FIG.  7   , the method  700  may finally comprise activating a LOCKED state of the quick coupler (block  704 ). In some embodiments, the LOCKED state may be activated by operating the coupler switch, e.g. by switching to a ‘permanent lock’ setting. In the same or other embodiments, when the LOCKED state is activated, the directional control assembly may operate in the second position connecting the cap end of the cylinder to the pump and the rod end of the cylinder to the tank, as best seen in  FIG.  10 D . Accordingly, the cylinder may partially or fully extend such that both the primary blocking member and the secondary blocking member move to the locked position, as best seen in  FIG.  9 E . Accordingly, both the first tool pin and the second tool pin of the work tool may be securely attached to the coupler, thereby completing the coupling process. 
     It may be appreciated that in some or all of the above embodiments, each step of method  700  may be operatively performed by an operator of the work machine. 
     Turning now to  FIG.  8   , a method of decoupling a work tool from a quick coupler is generally referred to by a reference numeral  800 . The method  800  may best be understood in consideration of  FIGS.  11 A- 11 E  and  FIGS.  12 A- 12 D , the former depicting an operation of the coupler and the latter illustrating an operation of the hydraulic assembly throughout the process. The method  800  may comprise activating an AUTOMATIC LOCKING state of the coupler (block  801 ), maneuvering the work tool to rest on a surface (block  802 ), activating an UNLOCKED state of the coupler (block  803 ), and fully separating the coupler from the work tool (block  804 ), each step of which will be discussed in greater detail below. Note that the method  800  assumes a starting configuration wherein the work tool is attached to the coupler, as seen in  FIG.  11 A . 
     The method may comprise first activating an AUTOMATIC LOCKING state of the quick coupler (block  801 ). In some embodiments, the AUTOMATIC LOCKING state may be activated by operating a coupler switch, for example by switching the coupler switch to an ‘automatic locking’ setting. 
     In other embodiments, the AUTOMATIC LOCKING state may be activated if/when the operator executes a specific order of actions. For example, the AUTOMATIC LOCKING state may be activated if and/or only if the operator first curls the coupler, and switches the coupler switch to a ‘temporary unlock’ setting, thereby first activating an UNLOCKED state of the coupler. In such embodiments, an onboard computer of the work machine, the controller of the coupler, or another system may detect the order of actions, which effectively command the coupler to activate the AUTOMATIC LOCKING state. 
     During the UNLOCKED state, a directional control assembly may operate in a third position connecting a rod end of the cylinder to a pump and a cap end of the cylinder to a tank, as best seen in  FIG.  12 A . Accordingly, the cylinder may retract such that both the primary blocking member and the secondary blocking member move to an unlocked position, as best seen in  FIG.  11 B . At the same time, a biasing member may bias the secondary blocking member toward a locked position. However, when the coupler is in the UNLOCKED state, the force applied by the biasing member may be negated by the cylinder&#39;s hydraulic pressure. 
     After a predetermined period in the UNLOCKED state, such as a time require to fully retract the cylinder, the coupler may enter the AUTOMATIC LOCKING state. The directional control assembly may operate in a float position connecting the rod end and the cap end to the tank, as best seen in  FIG.  12 B . This may reduce hydraulic pressure to the cylinder, such that the biasing force of the spring is no longer negated. The secondary blocking member may thus be biased by the biasing member to move to the locked position, while the primary blocking member may remain in the unlocked position, as best seen in  FIG.  11 C . 
     Returning now to  FIG.  8   , the method  800  may comprise the operator maneuvering the work machine to move the work tool to rest on a surface (block  802 ). In some embodiments, the work tool may be attached to the coupler only by the second tool pin, which is hanging from the hook of the coupler and prevented from exiting said hook by the secondary blocking member, as best seen in  FIG.  11 C . And as previously discussed, the coupler may be configured such that no amount of exit force exerted by the second tool pin can move the secondary blocking member away from the locked. Meanwhile, the first tool pin of the work tool may freely exit the notch of the coupler. More specifically, as the operator maneuvers the work tool, the coupler may rotate with respect to the work tool about the rotation axis T1 of the second tool pin, such that the first tool pin freely exits the notch. Furthermore, throughout block  802 , the directional control assembly may continue to operate in the float position, as seen in  FIG.  12 C . Accordingly, manipulation of the work tool during block  802  may occur without any actuation of the cylinder. 
     With continued reference to  FIG.  8   , the method  800  may finally comprise activating the UNLOCKED state of the coupler (block  803 ). In some embodiments, the UNLOCKED state may be activated by operating the coupler switch, e.g. by switching to a ‘permanent unlock’ setting. The ‘permanent unlock’ setting may differ from the ‘temporary unlock’ setting in that it is not followed by the AUTOMATIC LOCKING state. In the same or other embodiments, when the UNLOCKED state is activated, the directional control assembly may operate in the third position connecting the rod end of the cylinder to the pump and connecting the cap end to the tank, as best seen in  FIG.  12 D . Accordingly, the cylinder may retract such that the primary blocking member remains in the unlocked position, and such that the secondary blocking member moves to the unlocked position, as best seen in  FIG.  11 D . While the biasing member may still provide a biasing force on the secondary blocking member, said force may be negated by the cylinder&#39;s hydraulic pressure. 
     In the UNLOCKED state, the first tool pin may freely exit the notch if it has not already done so. Moreover, the second tool pin may freely exit the hook. Thus, in a final step of method  800 , the operator may fully separate the coupler from the work tool (block  804 ), as seen in  FIG.  11 E . Since the two components are not longer interlocked, the operator may simply maneuver the work machine to physically move the coupler away from the tool, thereby completing the decoupling process. 
     It may be appreciated that in some or all of the above embodiments, each step of the method  800  may be operatively performed by an operator of the work machine. 
     While the preceding text sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of protection is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims defining the scope of protection.