NSF-Funded Student Design Projects:
Switch Operated Ribbon Cutter

Designers: Henry Brolh, Mark Chuong, Will Barlow, David Sant
Client Coordinator: April Saval
Services to Enhance Potential (STEP)
Supervisor: Robert Erlandson, Ph.D.
Department of Electrical and Computer Engineering
Wayne State University, Detroit, MI 48202

INTRODUCTION

Services to Enhance Potential provides supported employment services for persons with developmental disabilities. One of the tasks assigned to several STEP clients involves cutting heavy, industrial-grade ribbon to specific lengths. The first ETL/STEP intervention to help make the process safer and error-free used a custom-designed manual ribbon cutter. The student using the manual intervention pulled the ribbon to a marked place on the cutting platform and then rolled a blade cased in a wooden box over the ribbon, cutting it to the proper length (see documentation on “Adapted Manual Ribbon Cutter” for more details). While successful for several STEP clients, this method of cutting ribbon is still beyond the capacities of other workers with disabilities. The switch operated ribbon cutter automates the measuring and cutting processes so that workers with severe cognitive and/or physical limitations can competently participate by simply hitting a single switch.

SUMMARY OF IMPACT

The switch operated ribbon cutter provides a job for workers who do not have the physical and/or mental capacities to measure and cut on their own. After the worker hits the switch, the device measures the ribbon to the pre-defined length and then automatically cuts it to the proper length. Staff may adjust the length of ribbon to be cut for each session, making it easy for workers and staff to switch from one job to the next, and the designers made the device is easy to maintain.

TECHNICAL DESCRIPTION

The ETL Ribbon Cutter is designed to provide a means of dispensing and cutting linear material, such as ribbon, to pre-measured lengths.  Once the desired length has been defined, the system will store that setting and automatically dispense and cut ribbon at that length each time the user switch is been pressed. The system consists of a ribbon spool, cutting mechanism, and control box (figure 1).

The system is controlled by two toggle switches located on the rear of the control box (figure 2).  The power switch turns the unit on and off while the mode switch allows the user to program the cutter for a new length (Program Position) or simply dispense ribbon (Run Position).  A 3.5mm jack is also located on the control panel. This jack is used to connect the device to a user switch.  Each time that the switch connected to this jack is closed, the system will activate and dispense ribbon.

When the user hits the user switch in “run” mode, the ribbon is fed into the cutting mechanism, which is powered by a DC motor at 29RPM, until it has advanced to the programmed length. An encoder wheel attached to the cutting mechanism determines when the programmed length has been reached, at which time an electric actuator activates the cutting arm. This process repeats each time that the user hits the switch.

Staff may program new ribbon lengths by switching into “program” mode. To set the new ribbon length, one holds the switch down, which causes the ribbon to feed into the cutting mechanism, until the desired length has been reached. After confirming the correct length, one switches back into “run” mode, at which time the system is ready to use.

The ribbon cutter is equipped with sensors to detect the state of the device, and this status is displayed by a dual color LED located on the panel of the control box.  This LED can change from red to green to indicate various conditions. For example, if the light is green, the cutter is ready to be used. If it is red, it is in use. If it is flashing red, the device is out of ribbon, and if it is flashing green, it is ready to load ribbon. If the LED is alternating between red and green, the device is in the “program” mode.