Laser-View system monitors overhead cranes
Injection molders who mount a parts-handling robot atop an injection molding machine face a potential equipment collision each time an overhead crane used to lift and transport molds into and out of the work cell enters the production space.
For this reason, Laser-View Technologies developed Crane Sentry, a sensor-based overhead crane collision and position monitoring system.
Crane Sentry alerts the molding machine or crane operator to the crane’s proximity to any work cell with a top-mounted robot. The wireless system is designed for use in any injection molding facility, but especially those with space constraints above and around automated work cells, said Steven Lubeck, president of Laser-View, a supplier of noncontact sensors and measurement systems.
Traditionally, injection molders have avoided collisions by mounting a limit switch onto the rails of the overhead crane. The limit switches are wired to a central controller and can halt the operation of the crane. However, such a system is susceptible to mechanical failure and accounts only for a scenario in which a crane enters the work cell. It cannot determine if a top-mounted robot is in operation.
The Crane Sentry system uses distance measurement information from the laser sensor, which can be mounted on the hoist support on the wall, to determine the location of the crane bridge and the position of the crane hoist along the crane bridge at every moment.
CONTROLLER IS CORE OF THE SYSTEM
The Crane Sentry controller is the core of the system. Data from the laser distance sensor regarding the crane’s proximity to the work cells is handled through the controller.
The Crane Sentry controller connects to a master wireless gateway module that monitors, processes and relays input signals sent from a wireless I/O box (called a remote interface module) installed at each work cell. The remote interface module sends information regarding the status of the robot to the controller through the module.
The controller is aware of the position of the crane and also monitors the status and position of each top-mounted robot in the relevant work cells.
The system is also set up and configured through the controller. It communicates with the crane controls on the crane bridge and features a simple color touch-screen display. Users can teach or manually program the behavior of the crane as it enters or exits the work cell. “You can keep the trolley from going into certain regions,” Lubeck said.
The system comes in off-the-shelf configurations ranging from basic collision monitoring to advanced zone management, which allows the user to define and further protect areas within a facility and makes Crane Sentry suitable for a variety of industrial environments.
The system monitors and alerts the machine operator when an overhead crane is in the work space and at the same time sends a signal to the crane, robot control or machine controller to halt operations. It does not directly control the crane motion. Rather, it sends a signal to the crane controller to slow or stop the crane, or to enable crane motion. To prevent the crane from moving unexpectedly, the Crane Sentry controller never sends a signal to start the crane, Lubeck said.
Laser-View also can install sensing technology to monitor the height of the hoist. It can be a laser sensor or a limit switch, Lubeck said.
SYSTEMS IN USE
Laser-View’s Crane Sentry systems have been used primarily in the steel and fabrication industries with different types of sensor technologies. The Crane Sentry system for injection molding uses a wireless I/O collision monitoring system and laser sensors. The system is in operation in three injection molding facilities in the U.S., Lubeck said.
Crane Sentry comprises several technologies from other vendors for which Laser-View is the only authorized U.S. distributor. This includes laser distance sensors produced by Dimetix AG, Herisau, Switzerland.
Laser-View also provides laser distance sensors to determine silo and storage bin levels, roll diameter and width, and distance and position. The company cites structural monitoring and manufacturing and industrial automation as other core competencies.
Mikell Knights, senior staff reporter
Laser-View Technologies Inc.
Chester Springs, Pa., 610-497-8910,