Automatic Worktool Coupler
New Automatic Hose Coupler Description:
The HAWCTM Automatic Hose Coupler is a coupler device for attaching hydraulic implements to the end of an arm or boom of a piece of construction equipment without leaving the operator compartment. The coupler hydraulically unlocks the attachment from the arm and locks the coupler to the new attachment while automatically connecting two or four hydraulic lines that power the attachment.Click on this sentence to view skid steer loader Auto Hose Coupler Video
New HAWCTM Automatic Hose Coupler Background:Until now, there have been few companies that have been able to develop a device for coupling hydraulic attachments and their respective hydraulic lines to the end of an excavator or back hoe without the need for the operator to leave the cab. It has been done successfully on wheel loaders and other equipment applications, however, none have been totally successful to address the severe vibrations of a hydraulic hammers or hydraulic compactors in as harsh an environment as the end of an excavator stick. The existing designs use conventional hydraulic quick couplings mounted to a moving plate inside the body of the coupler. The drawbacks to this design are: the o-ring seals vibrate and are nibbled away, thus leading to having to be replaced often: the mechanism is subject to malfunction due to trapped rocks and dirt; the presence of the mechanism causes the coupler to be a design compromise; the fittings are susceptible to being hit by the coupler when the connection action is performed.
HAWCTM Automatic Hose Coupler Description:
The Leading Edge Attachments, Inc. HAWCTM Automatic Hose Coupler consists of two hooks that encircle pins that are mounted on the attachment. Two hoses go down to the locking pin on the coupler, and two (or four) hoses go down to the AHC pin. In attachment changes, the pins are hydraulically retracted and held under hydraulic pressure. The coupler is rotated forward using the bucket cylinder of the excavator or backhoe to align the latch bearing with the latch bracket. The hydraulic pressure is released from the coupler cylinder and hydraulic pressure unlocks and advances the pins into the latch bearing and thus locking the coupler to the attachment. The center of the pin of the new design is similar to a conventional flush faced non-spill coupling fitting except the design connects two coaxial flow passages instead of just one. The latch bearing on the attachment has mating components that insert in through the center of the pin thus causing the connections. The pin outside surface is hardened and still acts as a locking pin that can wear or be hit without harming the components of the hydraulic connections. The internal pieces on the latch bearing allow for radial free play and the connections allow for axial free play without allowing external forces to go through the hydraulic connection components. While the attachment is connected to the coupler, the connection is impervious to dirt and mud and stones because the connections are protected. The path for dirt to reach the connection area is tortuous and unlikely. The pin stays clean because the only time the end of the pin is uncovered is the brief time that the change over is being made.
HAWCTM Automatic Hose Coupler Advantages:
· The connections are non-spill.
· The design does not compromise the equipment quick coupler.
· The coupler is spring applied and hydraulic released.
· The internal connection allows for lateral movement.
· The attachments are easily convertible to the new system
· The operator can see if the connections are made properly.
· The hydraulic ball lock mechanically prohibits the pin from releasing under pressure.
· Service is easy.
· The design allows for high flows.
· The arrangement allows for simple in the field by-pass in the case of component failure.
Most types of construction equipment such as backhoes, excavators, wheel loaders and skid steer machines utilize various hydraulic attachments such as grapples, hammers, compactors, shears, crushers, etc., and non-hydraulic attachments such as buckets, blades, rippers, wheel compactors, etc.. To simplify the process of changing attachments, a coupler can be permanently attached to the stick or boom arm. The selected attachment can be removably attached to the coupler with a locking mechanism that is easier and quicker to use than hammering out linkage pins. The construction industry is changing over to these types of quick couplers from the conventional direct pin set up on the machines. The time saved in changing attachments equates to higher productivity and safety to the operator or contractor.
There are two major classifications of quick couplers for construction equipment. One class is the “Pin-Grabber” type of coupler that attaches directly to the conventional attachment that would have been pinned on the machine. The other class of coupler is the “Quick Change System” type that attaches to attachments that have special connecting surfaces that are unique to the system within one size class. One advantage of the “Pin-Grabber” type is that the operator can use existing attachments that are normally pinned on to the machine. One advantage of the Q.C. System type is that one can use the attachments across many different types of OEM machines. This type of system is favored with the rental houses and large fleet owners because the attachments can be used across all of their different brands of OEM equipment. The other advantages of this type of coupler system compared to the pin-grabber type, is better productivity due to lower total weight, and the shorter tip radius.
A further sub-class of each coupler type is the method of operation. There are manual operating couplers that require the operator to exit the cab and pull a pin in order to change attachments. This is the less expensive method while still utilizing the advantages of a coupler.
A second sub-class is the hydraulic coupler. This allows the operator to change attachments without exiting the cab. This method not only saves even more time, but because the operator does not have to get out of the cab, the method is safer. With this type of coupler, however, if the attachment is hydraulic, the operator is still required to exit the cab and manually hook up the hydraulic hose lines to the attachment.
The new third newer sub-class of the hydraulic coupler to emerge is the “Automatic Hose Coupler”. With this type, the operator is not required to exit the cab to change hydraulic attachments. The hydraulic lines required for the operation of the hydraulic attachment are automatically connected when the coupler is connected. This method is not only faster, but is safer to the operator because he will not be subject to the injuries related to connecting hydraulic lines. In the case of larger hydraulic lines, the time element and the safety issues become big factors when changing attachments. Trapped hydraulic pressure in the attachment lines makes hose connecting difficult. The Automatic Hose Coupler is the wave of the future in all markets of construction equipment.
There have been Automatic Hose Couplers (AHC) in the past and all of the designs have met with mechanical problems. Most of these units use commercial hose connectors that are on a track that align themselves to connect when the coupler connects. At lease one design utilized a special connector that was to address the inherent vibration and seal problems that occur. The U.S. Air Force released funds to develop their “Rapid Runway Repair” initiative that required the use of Automatic Hose couplers. None of the devices from that initiative were found to adequately survive the vibration and forces from hydraulic breakers and vibratory compactors.
The new Leading Edge Attachments, Inc. HAWCTM Automatic Hose Coupler device is currently in the development phase. The patented concept utilizes a method of attaching two fluid lines without the use of conventional hose connectors. The design is such that the vibration from the attachment is isolated from the sealing surfaces. High forces and vibrations from the attachment have little effect on the seals of the device. The coupler functions easily and wear is minimal, and the device is non-spill. The concept has been successfully tested on a 40,000 pound size class excavator and a skid steer loader switching from various non-hydraulic attachments to various hydraulic attachments. Seven patents that cover different aspects of the device have been granted.
The LEA HAWCTM AHC units consist of a two line co-axial connector that is integral to a coupler pin. Several size classes are being developed, however, the 65 to 100K pounds class excavator will be available first (Cat 330 and Cat 345). The channels were designed to handle the flow of the attachments of each machine size class.
Other size HAWCTM AHC units will be developed that will be able to be adapted to work in conjunction with the other size classes and types of construction equipment. The LEA plan is to eventually develop several sizes of the AHC units that will be adapted across the board on excavators, backhoes, skid steer loaders and articulated wheel loaders.
The industry trend in the backhoe and excavator quick coupler market is to have a hydraulic actuating method for disconnecting the attachment from the linkage without the need for the operator to leave the cab.
Most systems of this type involve the use of a hydraulic cylinder, hoses and a valve that taps into the hydraulic system of the vehicle. The cylinder is usually positioned so the cylinder is in the extended position when the pin is inserted. This causes the rod to be exposed to injury and contamination. This method also uses the cylinders less powerful rod end to extract the pin.
New Hydraulic Coupler Description:The new HAWCTM AHC attachment coupler system also involves the use of a cylinder, a switch, a valve, and hoses and does tap into the vehicle hydraulic system. One hose attaches to the bucket cylinder stick circuit and the other returns back to the hydraulic tank. The valve is mounted inside the excavator next to the main valve.
The new system is hydraulic apply, hydraulic release. This allows the cylinder to "push" the pin out to retract. There must be a pressure present in order to release the pin. If there is a loss of either electrical or hydraulic power, the pin will be held in the locked position. There is a wire that reaches from the solenoid to a locking toggle switch in the cab. Red lights and a beeper sound alerts the operator that the switch is in the retracted position.
New Hydraulic Coupler Operation:
In order to retract the pin the operator must move the switch to the unlatch position. The red light then goes on, the beeper sounds and the solenoid becomes energized. The operator must then fully extend the bucket cylinder in order to build up enough pressure in the cylinder to retract the pin. This position is a safe position with respect to the coupler because it is insured that the hooks of the coupler are indeed holding the attachment. One cannot simply actuate the switch and have the attachment fall to the ground. While the switch is still in the "unlatch" position, the pin will be held back retracted. The operator can use free hands to maneuver the vehicle to uncouple the attachment and to put the new attachment on. With the attachment in place, the operator need only throw the switch to the "latch" position and the pin will extend.
New Hydraulic Coupler Advantages:The cylinder uses the more powerful head end to extract the locking pin instead of using the less powerful rod end for this purpose. Extracting a frozen pin takes more force than inserting a free moving pin.
· *The cylinder is in the retracted position during the attachment working period. Because the cylinder is retracted, the rod is not exposed to being damaged from rocks and sharp objects.
· The hydraulic and lock apply, hydraulic release system is a safe method that prevents uncoupling due to hydraulic failures.
· The pin indicator readily shows whether the pin is fully inserted or not. The indicator can be viewed easily from the operator position.
· Even if electrical power inadvertently gets to the solenoid, the attachment has to be fully rolled forward in order for the pressure to build up in the actuating cylinder. In this position, the coupler hooks are fully engaged and the likelihood of the attachment falling off is minimized.
· Due to the cylinder being in the closed position during normal operation and that hot system oil is used for actuation, the system is not cold temperature sensitive.
Leading Edge Attachments,
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Revised: February 14th, 2013