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Backhoe Safety Computer

IP.com Disclosure Number: IPCOM000034801D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 3 page(s) / 98K

Publishing Venue

IBM

Related People

Kling, CC: AUTHOR

Abstract

The backhoe is a magnificent digging device and is reasonably safe when properly controlled by an experienced operator. As illustrated in the drawing, the backhoe, however, is subject to overturning if swung with a heavy bucket load; the backhoe is subject to flipping onto its back under certain situations of fixed rock or stump attack. The representative backhoe has an articulated digger arm and digger bucket, with hydraulic cylinders to provide motive power. There are two outriggers, which in normal operation are used to hoist the big drive wheels off the ground. It is fairly usual to combine the backhoe with a front loader; a load of dirt or rocks in the front loader bucket is often used as a safety counterbalance for backhoe work. The machine sits on outriggers and bucket, with wheels aloft.

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Backhoe Safety Computer

The backhoe is a magnificent digging device and is reasonably safe when properly controlled by an experienced operator. As illustrated in the drawing, the backhoe, however, is subject to overturning if swung with a heavy bucket load; the backhoe is subject to flipping onto its back under certain situations of fixed rock or stump attack. The representative backhoe has an articulated digger arm and digger bucket, with hydraulic cylinders to provide motive power. There are two outriggers, which in normal operation are used to hoist the big drive wheels off the ground. It is fairly usual to combine the backhoe with a front loader; a load of dirt or rocks in the front loader bucket is often used as a safety counterbalance for backhoe work. The machine sits on outriggers and bucket, with wheels aloft. The attitude of the digger arm and digger bucket are important. A heavily-laden digger, swung too fast or too far around, can overturn the backhoe if the arm is extended; if the entire backhoe is moved, it might be possible to lift the same load safely because the leverage is more favorable. The rule is: "buddy up to the big ones." That is, if the load is heavy or stuck, move the entire backhoe in close, facing the load directly along the axis of the machine, at right angles to the outriggers. The ton of rocks in the frontloader bucket adds to safety -- up to the point where all safety thresholds are passed -- but then adds a ton of rocks to the mess when the machine overturns. The improvement described herein instruments the hydraulic cylinders or equivalent stress members of the backhoe arm and digger, and of the outriggers, front wheels and frontloader bucket. Instrumentation senses both attitude and stress.

Instrumentation values are used to address lookup tables. Computer table lookup is used to relate the load stresses to acceptable norms for the current attitude of the arm and digger, to alter that attitude automatically to achieve the current dig or lift with maximum safety. The danger situation for flipping is the simultaneous digging or lifting at maximum arm extension plus overload (big rock or tight stump); the danger situation for rollover is the simultaneous fast swing and heavy bucket load with maximum arm extension. The danger may be very high for a fast swing at full extension with a full digger carrying a boulder. The danger may be very high in ordinary digging if a stump is firmly attached, so that the front of the backhoe lifts while the stump stays put. The danger may be quite tolerable for a slow swing at full extension with dirt in the digger. Lessening the extension generally lessens the danger because the lever arm is shortened. There is, however, a desire on the part of the operator not to move the backhoe and reset the outriggers unnecessarily -- hence the extension. There are situations where digger motion at lesser extension is the safe attitude, even though less digger motion at greater...