NISH Report: Team Catalyst Paper Folding Machine

Transcription

1 1 : Team Catalyst Paper Folding Machine ABSTRACT Ohio University s Team Catalyst was given a task to find a customer who was physically or mentally handicapped and required further assistance in order to get employment, or increase their current conditions in employment. We met and discussed with a non-profit organization, SW Resources, and determined that a solution was needed in order to help the company fold a weekly newspaper. The task at hand was to develop an assistive device that could fold a Wally s and Wimpy s Football Digest in a z-fold, crease it to less than 5/8 thick, and be easily operated by a broad range of handicapped persons while maintaining or increasing efficiency. The resulting solution led to a manually operated folding device that involves a few simple motions to make the fold and crease. Through testing and evaluation we have refined our design to make it work properly and have made recommendations for production of additional devices. Due to the simplicity of the steps and overall design of the device, we think that many different users could operate this device and maintain or increase efficiency compared to the current process. BACKGROUND/PROBLEM STATEMENT SW Resources is a non-profit organization located in Parkersburg, WV. They employ people with disabilities to provide them with jobs in all different areas. Mail Plus is a division of SW Resources which has several tasks for the employees in which they process over 1 million pieces of mail annually. One of these tasks is folding a weekly football digest called Wally s and Wimpy s Football Digest. This is a seasonal task that the workers assigned are having difficulty in performing. These newspapers must be z-folded squarely and placed in an envelope. The total package must be less than 5/8 inch thick. As of now, only employees with high dexterity can perform this task. We observed the workers performing the task by folding and creasing the papers by hand. The main concern expressed by SW Resources was the need to find workers with enough dexterity to carry out the task of folding Wally s and Wimpy s properly and effectively. The workers are having difficulty folding the newspapers squarely in order to fit in their designated envelopes. They are also struggling to maintain a final thickness less than 5/8 inch. The goal of this project is to create a low cost device for SW Resources to fold Wally s & Wimpy s newspapers focusing on ease of use to allow people with a broad range of disabilities to perform the task safely. The table below shows both the customer requirements and the target specifications. Table 1: Customer Requirements and Target Specifications Customer Requirements Flatten papers Ability to handle staples Ability to handle various thicknesses Maintain/Increase efficiency General safety Target Specifications 500/hr crease rate Z fold 5/8" max final product thickness Handle standard staples 1% failure rate

2 2 RATIONALE The overall design is based on ease of use that requires little coordination and mobility. It allows the user to easily fold the newspaper in the proper z-fold with only a few steps. In order to fold this paper manually, the paper must be lined up by hand in thirds which requires dexterity, precision and some mental capabilities that the users of our device may not have. By limiting the folding requirements to loading the paper and rotating a shaft 180, the dexterity and mental requirements are reduced immensely. This simplification of the folding process allows a wider range of users than were previously performing this process and in a more efficient manner. It also opens the specific job opportunity to a wider range of persons whom can successfully perform the task. Designing the device to have an inexpensive upfront cost will allow the company to purchase more of the units if they desire to, which in turn will allow the company to give more people the chance to hold this position and increase production rates if needed. DESIGN OVERVIEW Hinged Lid for Easy Access Handle Lever Slot to Load Paper Figure 1: Outside View of Device Figure 2: 3D CAD Model of Prototype The design is comprised of 3 main sub assemblies that all act together to accomplish the same common task of making a z-fold and creasing the edges. These sub assemblies are: an outer MDF base structure, an HDPE paddle layered between two HDPE moveable plates that provide the fold, and a roller assembly that provides the crease and flattening of the newspaper. The process begins by loading the newspaper into the slot on the outside of the MDF box into the paddle assembly. The user then rotates the paddle lever 180 to provide the initial z-fold. The paddle is then pushed forward to the rollers which grab the newspaper creasing it as it is fed through the slot in the back of the box to complete the fold/crease. The paddle handle is then pulled back and rotated to the original position to complete the process. Paddle/Plate Assembly The HDPE (High-Density Polyethylene) paddle is the primary folding mechanism that works in conjunction with two moveable plates to provide a z-fold. The paddle sits in grooved slots of the moveable plates which provide a flush surface on the top and bottom allowing the newspaper to easily slide through the paddle. As it is rotated the plates keep pressure on the newspaper at the paddle edges to crease it. This is accomplished by a 180 turn of the paddle by the user as shown in

3 3 Figure 5 of the appendix. There is a groove on the aluminum paddle handle that only allows for 180 turns and a 1 forward translation to transfer the paper to the rollers. A 4 aluminum lever arm with a ball handle was added to make it easier to use and more ergonomic. The moveable plates are 3/8 thick sheets of HDPE with four slotted holes that are directed by four guide pins. These slots were implemented (rather than holes) to prevent the plates from seizing during the rotation of the paddle. The bottom moveable plate sits on four springs to provide force on the paddle for creasing and to return the plate to the starting position. The top plate works in the same manner, but it uses its own weight instead of springs. HDPE was selected for the plates and the paddle blades because it is inexpensive, machinable, lightweight, and has a smooth finish. The smooth finish is needed (less friction) for easy loading, rotation, and transfer of the newspaper. Guide Pins Figure 3: Paddle and Plate Assembly Figure 4: Roller Assembly Roller Assembly The main purpose of the rollers is to provide the final flatness and creasing of the newspaper once it is in the z-folding position. Two inch diameter PVC rollers are wrapped in a rubber film to provide more friction to grab the newspaper to pull it through. The rollers are driven by a 120V AC low gear motor that direct drives the bottom roller. The top roller is the then driven by a pulley system to allow it to rotate in the opposite direction. Both rotate via stainless steel shaft inserted into ball bearings. A pulley system was chosen instead of a gearing system to avoid tolerance problems and due to the availability/cost of gears. A contact switch was implemented so that when the access panel on the top of the MDF box is opened the motor will shut off and stop the rollers. (See Figure 6 in the Appendix) MDF (Medium-Density Fiberboard) Outer Box This structure acts as the main base support for all other sub assemblies and is also the means in which the paper is loaded properly into the paddle. The box was designed so that when the paper is loaded through the slot it would touch the opposite wall and also sit flush with the outside of the slotted wall. This ensures that the user knows the paper is positioned correctly. A critical function of the box is to provide support for the paddle handle which allows it to rotate freely about one axis. This allows for easy transfer of the newspaper from the paddle to the rollers. The box is also the support for the guide pins/springs, motor, roller assembly, and houses all the

4 4 components inside a neat, safe, and portable unit. By containing all the sub assemblies inside one box it reduces the chance of a safety related incident by keeping workers hands out of all moving parts and away from electrical components. MDF was selected as a material because it is sturdy, easily cut, inexpensive and heavy enough to keep the device in place but not too heavy to carry. TESTING EVALUATION Testing has been performed by all group members in the shop. Minor adjustments were made throughout the testing process to adjust the quality. Such adjustments included a different motor with more torque to assist the rollers in ejecting the folded paper. With the previous motor the rollers would jam and wrinkle the paper. Once the new motor was installed it helped the rolling process greatly. When folding loading the paper, two different orientations of the paper were used to see what produced the best desired fold. It was decided to load the folded edge of the paper in the paddle towards the user. This produced the straightest edges on the final product. A better pulley system was also implemented after slip was noticed during rotation of the rollers. Pulleys with ridges were used in conjunction with a track belt to provide better grip and less slip. Another addition to the system was the use of two guide ramps between the exit of the rollers and the exit slot of the outer MDF box (See Figure 7 in Appendix). This prevented the newspaper from colliding with the wall (not exiting the box) and jamming up the rollers. The curved ramps direct the paper through the slot allowing for a smooth transition out of the box from the rollers. Customer testing is in the beginning process and results are still pending. Based on the customer feedback, adjustments are going to be made to improve the product to better satisfy them. Testing for the customer includes papers to be loaded, folded and ejected from the device. Areas to be considered are time it takes to fold, ease of loading, success rate (no jamming or damaged products) and the correct required thickness of 5/8. These areas are to be tested over a range of users with different levels of dexterity and mental capability. Testing amongst the team has revealed an average time of 9 seconds per paper to load, turn, push, and feed through the rollers. This was based on only 25 trials as limited newspapers are available since they are out of season. The remaining papers will be used for customer testing and even further refinements. Knowing this device will be used among a wide range of disabilities, we estimate that completion time per paper will range from 8-15 seconds. This will be under of very near SW Resources requirements of 500/hr. With the use of additional devices they may increase their folding times significantly. CONCLUSION Based on testing and evaluation that has been completed by the team members, it has been addressed that different material choices would greatly improve the results. This is true particularly with the paddle and moveable plates that are made from high density polyethylene. When machining, these parts had a tendency to bow and warp slightly due to the pressure from the tiedown clamps and the high cutting forces. This initially caused a loading issue because the tolerances were designed for a tight fit so that the newspapers could only slide through the paddle. Any gaps between the paddle and plates allow the newspaper to load over or under the paddle rather than through it. Aluminum or some other ridged and light metal material would be less likely to bow and therefore allow for tighter tolerances and hence increase loading efficiency. Overall the prototype was able to achieve our goals and complete the task at hand and we are very pleased with the result.

5 5 APPENDIX Figure 5: Cut Out View of Folding Process

6 6 Safety Switch Figure 6: Entire Assembly with Access Panel Open Figure 7: Guide Ramps Leading to Exit Slot of Outer Box

7 7 ALTERNATIVE TEXT DESCRIPTIONS Figure 1: This figure shows the outside of the complete prototype. It shows the location of the paddle handle, hinges on the top of the box, and also the loading slot. Figure 2: Is a 3D CAD model of the prototype that shows the internal parts of the device. It clearly shows the paddle in between moveable plates aligned in front of the roller assembly. Figure 3: Shows the paddle assembly and its rotating motion. It also shows that the moveable plates are guided by four guide pins to control translational motion. (Top plate removed for clarity) Figure 4: This figure shows the roller assembly. On the left side you can see the direct drive shaft going into the bottom roller. On the left side you can see the gearing system, driven by a belt. The rollers also have a rubber coating for gripping the paper. Figure 5: Shows the step by step folding motion. It shows the paper loaded in the paddle, between both moveable plates. This is followed by various paddle positions until a rotation of 180 degrees is finished and the paper is in the desired fold. Figure 6: This view focuses on the inside of the box with all parts assembled. The main feature here is the safety shut off switch that turns off the motor once the box is opened. Figure 7: Shows guide ramps on the back of the roller assembly. These two curved pieces of metal help guide the folded paper smoothly to the back slot of the box where it is ejected.