Arm assembly for excavation apparatus and method of using same
View Patent ↗An arm assembly for an excavator includes an arm comprising a first hook including a first open mouth. The arm further includes a first pin capturing system that selectively obstructs the first open mouth. A link is movable relative to the arm and comprises a second hook including a second open mouth. The second open mouth is oriented toward the arm, and the link further comprises a second pin capturing system that selectively obstructs the second open mouth. The first and second pin assemblies of an attachment are selectively captured in the first and second hooks. The pin assemblies include a sleeve rotatably positioned on an attachment pin that extends between ribs of the attachment. The sleeve includes a bore that closely receives the attachment pin and the length of the sleeve is selected so that the sleeve fits closely between the attachment ribs, thereby allowing the arm assembly to pick-up various attachments with different pin diameters, ribs spacings and pin-to-pin distances. The arm assembly can be coupled to and decoupled from an associated attachment by an operator without assistance from a ground crew.
1. An arm assembly for an excavator, said arm assembly comprising:
an arm comprising a first hook including a first open mouth, said arm further comprising a first pin capturing system that selectively obstructs the first open mouth;
a link movable relative to said arm and comprising a second hook including a second open mouth, said second open mouth oriented toward said arm, said link further comprising a second pin capturing system that selectively obstructs the second open mouth;
an attachment control cylinder operably coupled to said link for varying the position of said link relative to said arm; and,
first and second guide links located on opposite sides of said arm, each of said guide links extending between and pivotally connected to said arm and said link.
2. The arm assembly as set forth in claim 1 , wherein:
said first pin capturing system comprises: (i) a first pin-capturing member movably connected to said arm and movable between a first position where said first open mouth is configured to receive and release an associated attachment pin, and a second position, where said first pin-capturing member obstructs said first open mouth and captures an associated attachment pin in said first hook; and, (ii) a first hydraulic actuator operably coupled to said first pin-capturing member and operable to move said first pin-capturing member to and between its first and second positions; and,
said second pin capturing system comprises: (i) a second pin-capturing member movably connected to said link and movable between a first position where said second open mouth is configured to receive and release an associated attachment pin, and a second position, where said second pin-capturing member obstructs said second open mouth and captures an associated attachment pin in said second hook; and, (ii) a second hydraulic actuator operably coupled to said second pin-capturing member and operable to move said second pin-capturing member to and between its first and second positions.
3. The arm assembly as set forth in claim 2 , wherein said first and second pin capturing members are slidably movable between said first and second positions relative to said arm and link, respectively.
4. The arm assembly as set forth in claim 2 , wherein said first and second hydraulic actuators comprise first and second hydraulic cylinders connected to said first and second pin-capturing members, respectively.
5. The arm assembly as set forth in claim 2 , wherein:
a portion of said arm that defines said first hook comprises a first slot, and wherein said first pin-capturing member spans said first open mouth and comprises a first tip portion that is slidably received in said first slot when said first pin-capturing member is moved to said second position; and,
a portion of said link that defines said second hook comprises a second slot, and wherein said second pin-capturing member spans said second open mouth and comprises a second tip portion that is slidably received in said second slot when said second pin-capturing member is moved to said second position.
6. The arm assembly as set forth in claim 5 , wherein said first and second tip portions each comprise a wedge-shaped portion.
7. The arm assembly as set forth in claim 2 further comprising:
a stop pin, wherein said arm defines first and second receiving locations for said stop pin, and wherein said stop pin engages said first pin-capturing member and prevents movement of said first pin-capturing member from its second position to its first position when said stop pin is inserted in said second receiving location.
8. The arm assembly as set forth in claim 2 further comprising:
a stop pin, wherein said link defines first and second receiving locations for said stop pin, and wherein said stop pin engages said second pin-capturing member and prevents movement of said second pin-capturing member from its second position to its first position when said stop pin is inserted in said second receiving location.
9. The arm assembly as set forth in claim 2 , wherein said link further comprises an inner surface oriented toward said arm and wherein said inner surface comprises an unobstruded ramp surface that blends said inner surface into said second hook.
10. The arm assembly as set forth in claim 2 , wherein said second hook comprises an inner partially-cylindrical surface defined by a radius centered at an origin, said inner surface extending for not more than 180 degrees between first and second ends and comprising a mid-point that lies halfway between the first and second ends.
11. The arm assembly as set forth in claim 10 , wherein:
said link comprises first and second opposite axial ends and wherein said first axial end comprises a pair of aligned bores defined about a pivot axis, said aligned bores defining a pin-on location for pivotally connecting said link to said attachment control cylinder; and,
a hook angle of less than 90 degrees is defined between a first plane that passes through said mid-point and said origin, and a second plane that passes through said origin and said pivot axis.
12. The arm assembly as set forth in claim 1 , wherein said link comprises a first axial end and a second axial end, said second hook is adjacent said second axial end, and wherein said second mouth is oriented toward said arm and angled toward said first axial end of said link.
13. The arm assembly as set forth in claim 1 , wherein said arm further comprises an engagement point with which said second hook of said link is selectively engageable to prevent swinging of said link relative to said arm.