A construction machine accessory coupling mechanism

Abstract: A construction machine having a mobile chassis (101), a bom (103) mounted on the mobile chassis (101) and capable of swinging vertically, and an arm (105) pivotally connected to the bom (103). An accessory detachable mechanism connects to a tip end of the arm (105). An accessory (114) is releasably held by the detachable mechanism. The mechanism includes a pivotal four-bar linkage (109) defined in part by the arm (105). First and second attaching arrangements (112, 113) are associated with the mechanism and releasably engage respective first and second attachment parts (116,117) provided on the accessory. The first attachment arrangement includes hooks (112,113) which engage the first attaching part as defined by a connecting pin (116, 117) on the accessory. A pressure cylinder (111) is associated with the mechanism to effect relative engaging or releasing motion between the first (112) and second (113) attaching arrangements.

Description: In a construction machine for digging a drain or hole in the ground such as a so-called excavator, back hoe or the like, an accessory attached to an arm of the construction machine may be replaced by another accessory for a different task. The excavator has been typically employed for earth work or construction work and includes a bucket connected to the tip end of an arm. When the boom and bucket are swung, earth or sand can be dug for forming holes or drains. However, the excavator is used not only for digging holes or drains by means of a bucket, but may be diverted to other tasks. To this end, instead of the bucket, another accessory may be connected to the arm. For example, the bucket may be selected to have a size adapted for digging and trenching width, thereby enabling the excavator to work depending on the hardness of earth and sand and the width of holes or drains. Alternatively, a breaker may be connected to the tip end of the arm or a grip may be employed for carrying out destruction work or loading or unloading work. A combination of various kinds of these accessories enables the excavator to be adapted for various work, thereby improving its versatility at the work site. When the bucket is replaced by another accessory, the bucket is removed and another accessory for another task is manually connected to the arm. To achieve this a pin connecting the arm and the bucket is removed so that the bucket is detached from the arm. Thereafter another accessory is connected to the arm, and the pin is reinserted whereby the accessory and arm are connected. The detaching and attaching work involved is carried our manually, however, this takes much time and several operators and renders the work inefficient. If it were possible to readily exchange the accessory man power and work time involved in the replacement of the accessory would be reduced. If the operator of the excavator alone can detach and attach the accessory, and eliminate the operation involved in putting the pin in and pulling the pin out from the accessory, the work is done safely and reduces the time required for replacing the accessory, and involves high work efficiency. One prior art publication which discloses a construction machine having a coupling mechanism with the aforesaid objectives is AU-557 890. The features common to AU-557 890 and essential to the present invention are indicated in the pre-characterising part of claim 1. AU-557 890 discloses a coupling mechanism which has oppositely facing hook like parts which can be engaged, a first of the hook like parts with a first mounting pin mounted in pin holes in an accessory (tool) and the second hook like part with a similar, parallel, spaced second pin. To secure the accessory, one of the hook like parts is displaced away from the other by an hydraulic cylinder. In FR-A-2 304 726 an accessory of conventional type, having pin holes for two mounting pins, can be attached to an arm tip by a coupling mechanism having pins which can be projected by a hydraulic ram to be received into the conventional pin holes. Neither of the aforesaid coupling mechanisms resolve the aforementioned problems in a completely satisfactory manner and accordingly the present invention provides a construction machine having an articulated arm assembly mounted on a chassis, and a coupling mechanism mounted on the end of the arm assembly to enable an accessory to be coupled to the end of the arm for use so that the accessory can be swung, in use, by the action of an hydraulic ram engaged with the coupling mechanism, said accessory being a standard accessory having two parallel spaced pins for mounting onto the tip of an arm of the arm assembly, said coupling mechanism comprising a hook member disposed to hook a first pin of the accessory mounting pins, characterized in that, a latch element is disposed on the arm whereby, as the accessory is lifted by the arm assembly the second of the accessory mounting pins swings to engage in the latch element. More particularly the latch element on the arm may comprise, a groove disposed to receive the second accessory mounting pin, a holding body swingably supported on a shaft and positioned inside the arm, said holding body having a holding portion and a spring to bias the holding portion to latch the second pin, a push body, fixed to a front surface of the holding body whereby the impact of the second pin with the push body displaces the holding body to enable the holding body to latch the second pin. In a preferred embodiment of the invention the latch element has a lever displaceable by the movement of a cylinder rod projecting from an hydraulic cylinder to swingably displace the holding body to release the second pin. An example of an excavator construction machine equipped with an accessory coupling mechanism according to the present invention, will now be described, with reference to the accompanying figures; in which, Figure 1 is a perspective view of an excavator employing the coupling mechanism; Figure 2 is an enlarged view of the a coupling mechanism shown in Figure 1; Figure 3 is a cross sectional view of a tip end of an arm having a latch mechanism; Figure 4 is an exploded perspective view of the latch mechanism in Figure 3; Figures 5(A) to 5(C) are views showing operations of the accessory coupling mechanism according to the fifth embodiment. The construction machine comprises a mobile chassis 501 having an engine and the like mounted thereon and an endless track 502 at right and left sides of the lower portion thereof and capable of freely moving front and rear, left and right. The mobile chassis 501 has a C-shaped boom 503 attached to the front portion thereof so as to be vertically swingable. A pair of first hydraulic cylinders 504 are provided between the boom 503 and the chassis 501 to right and left sides of the central portion of the boom and at the front portion of the mobile chassis 501 whereby the boom 503 can be vertically swung. An elongate arm 505 is connected to an upper end of the boom 503 so as to be vertically movable. A second hydraulic cylinder 506 is interposed between a central portion of the boom 503, at the rear surface thereof, and a rear end of the arm 505, whereby the arm 505 can be vertically swung relative to the boom 503. A bucket cylinder 507 has a rear end pivotally connected to a rear central portion of the arm 505 and a tip end provided with a cylinder rod 508. The accessory coupling mechanism includes a pair of rising links 509 pivotally connected to the right and left sides of the cylinder rod 508. Lower ends of the rising links 509 are pivotally connected to a portion adjacent to a tip of the arm 505 one each at each side thereof. A pair of connecting links 510 are pivotally connected to the tip end of the cylinder rod 508 one each to each of the right and left sides thereof. A body 513 is pivotally attached between top ends of the connecting links 510 and the tip end of the arm 505. A substantially square shaped link mechanism is formed by the pairs of rising links 509, connecting links 510 and body 513. The connecting links 510 have upper hooks 511 fixed thereto at right and left sides of the upper portion thereof. A bucket 517 has a known structure and has an attached body 518 connected thereto at a part of the periphery thereof. Parallel first and second holding pins 519 and 520 are fixed to the side surfaces of the attached body 518 at a predetermined spacing. A holding groove 515 is opened in the tip end of an arm 505. The holding groove 515 is of a slit shape in the lateral direction thereof and has a length conforming to the longitudinal direction of the arm 505. A support shaft 535 is positioned inside the arm 505 and fixed to a portion adjacent to an innermost end of the holding groove 515. The support shaft 535 has a sickle-shaped holding body 536 swingably supported thereto. The holding body 536 extends in the direction of the holding groove 515 and has a tip end bent in a substantial L-shape for forming a holding portion 537. The holding portion 537 is slightly remote from the innermost position of the holding groove 515 so that the holding portion 537 contacts a holding pin 520 provided on bucket 517 at the side of the opening of the holding groove 515 when it is positioned at the innermost part of the holding groove 515. A push body 538 having a substantially triangular shape in cross section is fixed to a front surface of the holding portion 537. A release lever 539 protrudes downward from the holding body 536 at the portion adjacent to the support shaft 535. The holding body 536 has a spring 540 which has one end held thereby at the central portion of body 536 and another end held by a spring seat 541 protruding from the inner wall of the arm 505. Accordingly, the holding body 536 is always biased counterclockwise by the spring 540 about the support shaft 535. A hydraulic cylinder 545 is positioned inside the arm 505 for a release operation and has a cylinder rod 546 directed in the direction of the support shaft 535. The cylinder rod 546 has a tip end to which an extension plate 547 is connected and directed downward. The extension plate 547 has a rod 548 at the lower end thereof so as to be in parallel with the cylinder rod 546. The rod 548 is directed toward the side surface of the release lever 539 at the tip end thereof. A state where the attaching operation of the accessory (the bucket 517 in this case ) starts is illustrated in Figure 5(A). The pin 519 is hooked by the upper hooks 511 to connect the bucket 517 to the arm. Then, the bucket cylinder 507 is contracted when the bucket 517 is suspended by the upper hooks 511. At this stage, the rising links 509 are turned clockwise about the pin 526, thereby pulling pawl holders 510 rightward. Accordingly, both the upper hooks 511 and the bucket 517 are pulled rightward so that the holding pin 520 of the bucket 517 is relatively moved toward the tip end of the arm 505. Inasmuch as the holding groove 515 is defined at the tip end of the arm 505, the holding pin 520 is inserted into the slot 515. As the holding pin 520 contacts the rear surface of the push body 538, the holding body 536 is forced to turn about the support shaft 536 against the resilience force of the spring 540 since the rear surface of the push body 538 is inclined so that the holding pin 520 is inserted into the innermost end of the holding groove 515. When the holding pin 520 is positioned at the innermost end of the holding groove 515, the holding body 536 is rotated counterclockwise by the spring 540 so that the holding portion 537 moves to close the opening of the holding groove 515. As a result, the holding pin 520 is prevented from being drawn out of the holding groove 515 whereby the holding pin 520 is connected to the tip end of the arm 505 as illustrated Fig. 3. As illustrated in Fig. 5(C), the holding pin 519 is hooked by the upper hooks 511 while the holding pin 520 is fixed inside the holding groove 515 so that the bucket 517 is securely connected to the arm 505. Since the holding groove 515 is closed by the holding portion 537, the holding pin 520 can be turned at the tip end of the arm 505. Accordingly, the bucket 517 can be turned about the holding pin 520 by the operation of the hydraulic cylinder 507 so that the construction machine having the detachable mechanism can operate in the same way as the conventional excavator. An operation of the removal of the bucket 517 from the tip end of the arm 505 will be described hereinafter. The tip end of the bucket 517 is forced to contact the ground and the hydraulic cylinder 545 is operated to push the cylinder rod 546. Since the rod 548 moves toward the tip end of the arm 505 and the tip end of the rod 548 pushes the release lever 539, the holding body 536 turns clockwise about the support shaft 535 against the resilience force of the spring 540. As a result, the holding portion 537 closing the holding groove 515 moves upward, whereby the holding pin 520 slides in the holding groove 515 and is pulled out of the tip end of the arm 505. These operation can be carried in sequence as illustrated in Figures 5(C), 5(B) and 5(A).

Claims: A construction machine having an articulated arm assembly (503, 505) mounted on a chassis (501), and a coupling mechanism mounted on the end of the arm assembly (503, 505) to enable an accessory (517) to be coupled to the end of the arm (505) for use so that the accessory (517) can be swung, in use, by the action of an hydraulic ram (507) engaged with the coupling mechanism, said accessory (517) being a standard accessory having two parallel spaced pins (519, 520) for mounting onto the tip of an arm (505) of the arm assembly (503, 505), said coupling mechanism comprising; a hook member (511) disposed to hook a first pin (519) of the accessory mounting pins (519, 520), characterised in that, a latch element is disposed on the arm (505) whereby, as the accessory (517) is lifted by the arm assembly (503, 505) the second of the accessory mounting pins (520) swings to engage in the latch element on the arm (505). A construction machine according to claim 1 wherein the latch element on the arm (505) comprises, a groove (515) disposed to receive the second accessory mounting pin (520), a holding body (536) swingably supported on a shaft (535) and positioned inside the arm (505), said holding body (536) having a holding portion (537) and a spring (540) to bias the holding portion (537) to latch the second pin (520), a push body (538), fixed to a front surface of the holding body (536) whereby the impact of the second pin (520) with the push body (538) displaces the holding body (536) to enable the holding body (538) to latch the second pin (520). A construction machine according to claim 2 wherein the latch element has a lever (539) displaceable by the movement of a cylinder rod (546) projecting from an hydraulic cylinder (545) to swingably displace the holding body (536) to release the second pin (520).

Inventors: KISHI MITSUHIRO, KISHI, MITSUHIRO
Applicants: JAPANIC CORP, JAPANIC CORPORATION
Application year: 1991
Main classification: E02F3
IPC codes: E02F3