Crane Safety Design Project TEAM 4Bisbee, Saylor, Sopher, &Young
Purpose: To design a device to aid in the prediction and prevention of crane tipping for a private customer. It was determined through independent research and customer correspondence that: • The crane should have the latest safety features available • The crane should be able to operate in various climates • Overload signals should be generated when the boom is lifting, not transitioning • Device should be stable in multiple settings • Crane and operator should be able to communicate with each other easily and effectively • All users should be trained on the new device • Device should generate a visual and audible warning • The device should effectively prevent tipping Customer Specifications Include: -cost effectiveness (<$3000) -OSHA rating (conforms to current OSHA standards) - Rapid response (< 1 second) -Communication (crane, operator, and system must communicate at freq. of >1MhZ) -Training Program (12 hours operator, 6 hours rigger) -Tip prevention (effectiveness of >99.9%)
Concept Generation Concept A: Counterweight System Concept B:Air Pressure Sensor This concept utilized suctioning feet and internal pressure sensors in the outrigger legs to generate a warning signal whenever a pressure differential was generated within the leg duirngnormal operating. -This system utilizes hydraulic counterweights located at the back of the crane to counterbalance any significant tip inducing torques. Concept C: Wireless Angle Measure Concept D: Load Cells -This concept used the Wireless Angle Measure developed by Dr. Chris Coulston to track the angular motion of 2 adjacent sides of the crane. This information would be sent wirelessly to a display unit showing the angular displacement from a zeroed position within an accuracy of one degree. -This concept relies on placing load cells in the feet of each outrigger leg, and utilizing a PCL (programmable logic controller) to generate warning signals whenever load sizes became critical.
Implementation As earlier described our design uses a Wireless Angle Measure, accurate to within one degree, to measure angular displacements of 2 adjacent sides of a crane. Each device will be zeroed in the cranes operating position. Each transmitter will send a signal to a receiver wirelessly up to 100 feet away, line of sight. The receiver will display both displacement values on two seven segment displays. The transmitter will also be wired to a box within the operator’s booth that will display the same information. This will eliminate any interference issues. Using this information operators or job supervisors will be able to make informed decisions about crane positioning, load size, boom extension and angling. Using displacements instead of torque calculations eliminates the need for a CPU to calculate based on load and position of the crane, and will display real time, in numbers, the movement and stability of the crane. This also reduces the cost of our solution, which is attractive to all potential customers.
WIRELESS WIRED BOX (INTERNAL) RECEIVER SIGNAL TO HEX SIGNAL TO HEX HEX TO SEVEN HEX TO SEVEN SIGNAL ACCEL TO HEX CONVERTER TRANSMITTER ACCELEROMETER WAM TRANSMITTER UNIT FUNCTIONAL BOX DIAGRAM OF SIMPLIFIED COMPONENTS FOR CRANE SAFETY UNIT
RENDERINGS RECEIVER ANTENNA LED DISPLAYS SPEAKER Simulated 3D model of Receiver Unit Rough Drawings of Assembled Components
Testing and Analysis Testing1) Signals strength testing dependence upon both distance and transmission through materials.2) Angle verification testing based on zeroed positions from a central rotor.3) Durability testing on physical unit/prototype/materials. This testing is to be outsourced to an independent testing firm which complies to international standards of performance (ETL/INTERTEK). All testing to be accompanied by certified engineers report for internal analysis. Additional testing4) Real time testing on small crane in minor (preventable and correctable) tip situation to verify proper functioning. This is to be performed and verified by the individual crane operating outfitters, based on prior testing and analysis. Estimated Time to Test: > 1 monthPredicted Cost of Testing: $10,750
COST ANALYSIS Cost Per Unit: $120 per (Unit TRANS, REC, WREC) Testing and Research: $10,750 Miscellaneous: $5,000 TOTAL OF DEVELOPMENT $15,870
Product Development It was the consensus of the team that the Wireless Angle Measure concept could be developed and used for additional applications with enhanced safety features per budget. OPTIONSWireless Angle Measure with Counterweight System: A combination concept of A and C, where the proposed counterweight system would be used in conjuncture with WAM to balance crane in the event of critical angling. Wireless Angle Measure with Badge Scan: A badge-activated entry system to the crane would be integrated to the WAM system. This would keep log of all operators of the crane as well as which operators generated critical angling and at what time & date the angling occurred. This will monitor safe usage of the crane and track users. Wireless Angle Measure with Automatic Hault: This integrates an automatic halt of the crane’s boom operation whenever a critical angle occurs. This will restrict the movement of the boom to inward (toward the crane) and downward (smaller angle of lift) motion to reduce the torque and correct the critical angle. Normal operation will only occur when critical angle is resolved. Wireless Angle Measure with Automatic Hault and Badge Scan: This integrated the prior two ideas. Crane operation will resume at a forced badge override from the operator, which will be logged into the system with time & date. All badge scan options assign responsibility of the crane to the badge holding operator. Safe usage could be used to effect payment and retention.
Conclusion The utilization of wireless high frequency communication increased the effectiveness and safety factor of our design. Eliminating the need for a CPU improved our overhead costs. The WAM unit can be used in conjuncture with various other devices to create new devices equally or more effective than the WAM itself. The design approach helped us narrow down our stream of ideas into several debatable concepts. Teamwork helped us generate a strong solution to the problem of crane stability and safety.