Dunnage conversion machine and method with downstream feed monitor
View Patent ↗A dunnage conversion machine provides an improved electronic monitoring and control system for detecting and resolving many jamming conditions before they require significant operator intervention. The machine includes a conversion assembly with a feeding device that feeds the sheet stock material through the machine, and a sensing device downstream of the feeding device to monitor movement of the stock material downstream of the feeding device and to output a corresponding signal. A controller controls operation of the feeding device in response to the signal from the sensing device. The controller uses the signal to detect a potential jam condition and controls the feeding device to prevent or minimize the occurrence or severity of the jam condition, thereby minimizing the amount and degree of required operator intervention.
1. A machine for converting a sheet stock material into a relatively lower density dunnage product, comprising: a conversion assembly for converting a sheet stock material into a relatively lower density dunnage product, the conversion assembly including a feeding device to feed the sheet stock material through the conversion assembly, wherein the feeding device includes at least one rotatable feed member that extends into a path of the sheet material; a sensor downstream of the feeding device to detect the speed of the sheet stock material at a point downstream of the feeding device, the sensor being configured to provide an output corresponding to the detected speed; and a controller that controls the feeding device based on the output from the sensor, where the controller is configured to control the feeding device by slowing the feeding device when the sensor detects a jam condition where the detected speed falls from a first speed above a predetermined value to a second speed at or below the predetermined value; wherein the sensor includes a rotatable member extending into a path of the sheet material and an encoder connected to the controller that converts rotation of the rotatable member into an electrical signal output to the controller.
2. A machine as set forth in claim 1 , where the controller is configured to control the feeding device by slowing the feeding device when the sensor detects the jam condition where the feeding device is energized and no movement is detected by the sensor during a predetermined period.
3. A machine as set forth in claim 1 , where the feeding device includes a pair of feed members on opposing sides of the path of the sheet material to feed the sheet material therebetween.
4. A machine as set forth in claim 1 , where the sensor includes at least one wheel that is biased into the path of the sheet material and is movable out of the path of the sheet material.
5. A machine as set forth in claim 1 , where the at least one feed member includes at least one of a friction wheel, a paddle wheel, and a gear.
6. A machine as set forth in claim 1 , where the conversion assembly includes a converging chute upstream of the feeding device that converges in at least one dimension in an upstream-to-downstream direction.
7. A machine as set forth in claim 1 , further comprising a severing device downstream of the feeding device to sever discrete lengths of dunnage from the sheet material, the controller controlling the severing device in coordination with the feeding device.
8. A machine as set forth in claim 1 , further comprising an output device coupled to the controller, where the controller is configured to signal the output device when the jam condition exists.
9. A machine as set forth in claim 1 , where the sensor downstream of the feeding device to detect the speed of the sheet stock material is a first sensor, and further comprising a second sensor that detects operation of the feeding device.
10. A machine as set forth in claim 1 , further comprising an input device coupled to the controller for an operator to indicate that the jam condition has been resolved.
11. A machine as set forth in claim 1 , where the controller is configured to control the feeding device by stopping the feeding device when the feeding device is energized and no movement is detected by the sensor after a predetermined period.