Group 23 - Swingline Electric Stapler

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Contents

Executive Summary

Our objective is to describe in detail how a personal electric stapler works. This product, as well as a regular stapler, only serves the function of stapling a stack of papers our stapler however does this automatically by using electric power. On the following page we show how to disassemble this product by accurately describing the disassembly steps. The tools that were used in each step are mentioned as well as a brief description of what difficulties each step presents. We included several pieces which we modeled in SolidWorks as well as actual pictures of the electric stapler. We also discuss in detail what materials are used to make this product and why these components are made of the specified material. To conclude this report we give recommendations and modifications that we think should be made to the stapler to improve the product. Improvements include materials used, ergonomic modifications to improve customer satisfaction and hopefully boost sales, and mechanical design changes that would probably save Swingline money overall and hopefully make the product cheaper for the consumer.

Introduction

The product that we analyzed was a Swingline personal electric stapler. This stapler works by consuming electric energy, received either through an AC to DC power adepter plugged into a wall outlet or through four AA batteries, and converting it, first into rotational energy and finally into linear energy which can punch through a stack of papers. This stapler is marketed to big businesses and offices with very busy staff. This is because big companies would be stapling large quantities of thin handouts. The Swingline personal electric stapler is a big seller because it is cheaper in comparison to the big industrial staplers but it can still easily staple high volumes of 15 sheets of paper or less and it is jam resistant. Another benefit of this stapler is it makes stapling easier for consumers with injuries, such as carpal tunnel. For this project we did most of the analysis and dissection as a group which maximized our efficiency and reduced time spent on meetings. While working in a group our answers were more precise and well rounded since we were able to combine input, on the spot from every member. We did the dissection as a group so that every group member shares the same experience and has the same knowledge of the stapler. We were all responsible for each step of the project.

Before Disassembly Section

The purpose of our product is to fasten two or more pieces of paper together using metal staples. The Swingline personal electric stapler was designed to do this faster than a standard stapler. This product converts DC electrical energy to mechanical energy using a motor and gears. *however this product can operate on batteries or a wall outlet when we use the supplied AC to DC power adapter. Our product is brand new and it operates well. As you insert paper a trigger is activated which starts the motor, resulting in a stapled stack of paper. When we operate our stapler it makes a whirling noise as if it has straight cut gears meshing and rotating inside, probably rotated by a small electric motor. Before we disassembled the Swingline personal electric stapler, we guessed that it would be comprised of approximately 20 pieces, including hardware.

We think that our stapler is composed of six different types of material, which are:

  • Plastic
  • Steel
  • Copper
  • Rubber for insulation
  • Glue
  • Solder

Disassembly Procedure

We used four different tools and our hands in the disassemblly of our stapler. These tools included:

  • A small Phillips head screwdriver
  • A small flat head screwdriver
  • A soldering iron
  • A pair of needle nose pliers


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Process Table

Disassembly Process Table
Step# Process Tool(s) Level of Difficulty Image
1 We started disassembly by removing the small rubber feet on the bottom so that we could gain access to the screws which connected the outer shell. For this process we were able to use our fingers to pull out the four, circular, rubber feet and then we used the Phillips head screwdriver to remove the four screws on the bottom which connected the lower outer shell to the middle shell. Hand, Phillips head screwdriver This step was very easy. Step 1b.jpg
2 After the removal of the lower outer shell we had to separate the electric receiver which was clipped into it. We did this by spreading the two clips far enough apart for the electric receiver to be slid out; we used our hands for this step. Since it required a certain amount of force to separate the clips, we had to be careful not to break the clips and to avoid any damage to the wires since multiple wires were connected to this device. Hand Due to the caution we had to exercise in order not to break anything, this step was moderately difficult. Clip.jpg
3 Next we removed a retaining clip and spring that was located on the underside of the middle shell of the stapler. The function of the spring is to keep the staple tray in a neutral position. Removing the spring was somewhat tedious since the spring and cir-clip are so small. For this step we used the needle nose pliers to pull on the cir-clip and a flat head screwdriver to help separate the clip and pry it off. Flat head screw driver, Needle nose pliers Since the pieces we had to disassemble in this step were so small this step was also moderately difficult. Step 3e.jpg
4 Next, using a Phillips head screwdriver, we removed the two remaining screws that held the upper outer shell in place. Then we had to squeeze the sides of the upper shell with our hands to disengage the two clips on either side which connected it to the middle shell. Hand, Phillips head screwdriver This step was very easy.
5 By this time, we could see the skeleton of the stapler. Our next step was to de-solder the wires attached to the motor so we could remove the gear box. It was necessary to de-solder the motor first since the motor could not be removed without disassembling the gearbox. To do this we used the soldering iron to melt the solder on the motor so we could disconnect the wires. Soldering Iron This step was difficult because we had to be careful not to melt the plastic on the motor with the heat of the soldering iron but at the same time we had to get the solder hot enough to melt. Step 5b.jpg
6 The next step was to remove two small screws which held a plastic gear retaining bar in place. For this we used a small Phillips head screwdriver and the bar was easily unscrewed and removed. Phillips head screwdriver This step was easy Step 6b.jpg
7 Then we had to remove the trigger (which helps to control the motor) attached to the staple punch. The trigger stops the motor when the staple punch reaches the right position in its travel so that it is always ready to staple papers. There was only one screw we had to remove with the Phillips screwdriver. Then we had to remove the wires from the retaining clip. Phillips head screw driver This step was easy. Step 7a.jpg
8 The next step was to remove the gearbox. To do this we removed the eight screws (four on each side) retaining the gear box and “stapler puncher”. For this step we used the Phillips head screwdriver. Phillips head screwdriver This was an easy step because we had easy access to all of the screws and then the gearbox just pulled out. Gearbox removal b.jpg
9 After we removed the gearbox, we disassembled it. There were two retaining screws that held the gearbox housing together. We were able to disassemble the gearbox by removing the two screws with a Phillips screwdriver and then pulling the two halves apart. We had to apply a relatively large force to pull apart the two halves but at the same time we had to be careful not to break anything or lose any pieces as the assembly came apart. Philips head screwdriver For this reason, this step was moderately difficult, especially in comparison to the other steps. Gearbox.jpg
10 Once the two halves of the gearbox were separated the internal gears easily pulled out. To remove the motor we used a small flat head screwdriver to pry the small gear off of the shaft of the motor which then just slid out of the gearbox housing. Flat head screwdriver This step was easy Last step.jpg
11 None of the other components could be disassembled without compromising the integrity of the product and we wanted our product to work again when we reassembled it so we stopped disassembly here. - -

After Disassembly

Part Table

Table of components
Part Number Component Material Type and Reason for Selection Manufacturing Process Function of Component Other Description Quantity Image
1 Rubber Feet Rubber - Has a high coefficient of friction Machining (Stamping) To provide good grip on the desk top It's Black, malleable and has good grip 4 Feet.jpg
2 Screws Steel - Able to handle high load and stress without fatiguing and breaking Machining To hold parts together Phillips head, rigid, uniform and shiny 20 Screws.jpg
3 Outer Shell Plastic - Light and can handle a descent amount of stress; it is also cheaper to have complex shapes on and mass produce something that is plastic Injection Molding Houses all internal parts Black, rigid, bulky 3 Outer housing a.jpg
4 Spring Steel - Will not fatigue or break and it is a conductor Forming, Shaping and Machining Keeps pressure on staple / Conduct electricity and keep pressure on the batteries / Keeps staple tray in a neutral position Spiral shaped, shiny, small and elastic 4 Spring.jpg
5 Wires Copper - Very good conductor of electricity, Plastic - To insulate Machining Transfers electricity Flexible, thin, white, red, green, blue, black, and yellow 13 Wires a.jpg
6 Motor Plastic - Electrical insulation, Steel - To withstand vibration and other stresses Metal Casting To rotate gears Small, powerful, silver, and mostly round 1 Motor.jpg
7 Internal Housings Plastic - Light and can handle a descent amount of stress; also easy to mass produce complex shapes which would be expensive to machine Injection Molding Houses gears and "staple puncher" Black, rigid 2 Gearbox housing.jpg
8 Gears Plastic - Cheap, light, easier to make than metal, and the gears do not experience high stresses Injection Molding To actuate "staple puncher" White, lubricated, round with teeth, different sizes 4 Gears.jpg
9 Trigger / Electric switch Plastic - Light, cheap, low stress situation, insulator / Metal (electrical components which control the flow of electricity) - To conduct electricity, Injection Molding(plastic) / Machining(steel) To detect paper and activate the stapler; Then to detect staple puncher position in order to stop the motor at the right time Small, clicks when pressed, black and silver, light 2 Trigger c.jpg
10 Staple Puncher Steel - Strong and able to handle repeated stapling of thick paper or cardboards without breaking or bending Machining Punches staples into paper Silver, long, strong, cutout 1 Staple puncher b.jpg
11 Circuit Board Plastic - Cheap, light, easily made and mass produced / Copper - Very good conductor of electricity / Electrical Components - Controls and determines the flow of electricity Manufactured Commands the activation of the stapler Square shaped, flat, delicate, green and brown with various electrical components 1 Circuit board c.jpg
12 Staple Tray Steel - Rigid, strong, resistant to breaking Forming and Shaping To house and store staples Long, rigid, silver, slides easily, rectangular 2 piece tray Staple tray.jpg
13 Tray Release Button Plastic - Cheap, light, resilient, and easily made Injection Molding Releases staple tray Gray, big, irregular shaped, attached to the outer shell 1 Button.jpg
14 AC Receiver Plastic - Light, cheap, low stress situation, insulator / Metal - Conducts electricity Forming and Shaping Receive power adapter plug Small, cylindrical shaped, silver and black 1 AC receiver a.jpg
15 LED Plastic - Cheap, light, can be made transparent, easily dyed different colors, insulator, easily mass produced / Metal - Conducts electricity and provides light Injection Molding To indicate if battery is low Small, red 1 LED.jpg
16 AC Adapter Plastic - Cheap, light, insulator, easily mass produced Injection molding To convert AC power in the home or office to DC power which the stapler operates on Big, square, black 1 AC adaptor.jpg


The shape of the internal components can not be changed significantly however, the outer shell could possibly be redesigned so it is less bulky. The components look the way they do because they all fit together and function properly, although there might be a better way to design the pieces so that they are more compact. There were some components however, which had a specific size and shape in order to enhance their function. First is the staple puncher lever which has a very specific shape and is comprised of metal. This lever takes the rotational motion of the gears and transforms it into linear motion; We think this component looks the way it does because its geometry helps increase the rotational force of the motor when transforming it into linear force which is used to punch the staple through your papers. The ability of the lever to function without binding was most likely a major concern as well when it was being designed. The second set of components which has a specific size and shape are the gears which had to be round since the initial motion in the stapling process is rotational and gears are perfect for performing rotational motion and providing rotational force. Another component which has a specific shape is the circuit board which is square. However, this is most likely due to convention rather than necessity. We believe that Swingline could change the shape of the circuit board so that it was curved which would be reducing "dead space" and would allow them to shrink the outer shell. The final component which has a specific size and shape is the staple tray which is in the shape of a rectangular prism because this is the best shape to fit and store staples. Overall, a common relationship that most of these components share is that they are small. We believe most of the components are small in order to reduce the size and weight of the stapler itself although Swingline could be more effective.

We would suggest the following changes and improvements be taken into consideration:

  • Less wiring: The wiring for the inner circuit was too long. It was in our way when we were assembling and disassembling the product and reducing wire length is a good way to cut cost.
  • The majority of the material used is plastic which is not as strong as a metal stapler. Even though the personal electric stapler is bigger and has more components than a metal, manually operated stapler, it’s somewhat lighter. This indicates that the electric stapler might not be as durable and that is not good, especially considering that it cost more than a manual stapler.
  • Fewer gears: Although the gears are needed, they could have engineered the gearbox so less gears are used and still obtain the same final result. That would save material and assembly cost.
  • Only one screw size: There were different size screws so when it came to reassembly we had to rely on our disassembly notes to determine where each screw belongs.
  • The size of the stapler was quite large and seemed bulky. We think that it’s possible to reduce the size of the stapler since the interior had open spaces that were not used at all, and a sleeker design would help sell this product to consumers (especially busy offices with cramped desks).

Solid Model

  • The lower housing, battery cover, middle housing, and staple plate assembly:

Almost.jpg

  • Just the lower housing:

Bottom shell.jpg

  • Just the middle housing:

Middle shell.jpg

  • Just the battery cover:

Battery cover.jpg

  • Just the staple plate:

Staple plate.jpg

Assembly

Process Table

Assembly Process Table
Step# Process Tool(s) Level of Difficulty
1 Start reassembly by inserting the motor into its designated hole in the gearbox housing. Using your fingers, press on the small motor gear. Then insert the remaining gears. Hand This is an easy step.
2 The next step is to align the pin on the gear wheel, attached to one side of the gearbox with the hole in the wheel attached to the other side of the gearbox. There is a small plastic bushing on the pin that had a tendency to slide off while we were trying to align the gearbox housing and match the wheels, which would rotate as we tried to press the pin into place. In addition to these obstacles, during this step we needed to keep the staple puncher lever on the pin as well as the plastic bushing while we reassembled the gearbox which further added to the level of difficulty. Once the housing was matched up and the pin was inserted in its hole the two gearbox hosing screws were reinserted and tightened to hold the gearbox assembly together. This step required us to use a Philips head screwdriver in conjunction with our hands. Hand, Phillips head screwdriver For these reasons this step was very difficult.
3 Once the gearbox was reassembled, the next step was to reinstall it. To do this we placed the gearbox and “staple puncher” assembly back into the middle shell of the stapler and installed the eight retaining screws (four on each side). For this step we used a Phillips head screwdriver Phillips head screwdriver This was an easy step because the gearbox was just set in place and we had easy access to tighten all of the screws.
4 Then we reinstalled the trigger attached to the staple punch. This step was confusing at first because we were concerned that we would reinstall the switch in the wrong orientation but we then realized that there is a locating pin on the “staple puncher” housing so that the switch could only be reassembled in the correct orientation. Then we had to reroute the wires through the retaining clip and insert the retaining screw with a Phillips screwdriver. Phillips head screwdriver This step turned out to be easy.
5 The next step was to reinstall the plastic gear retaining bar and the two small screws that hold the bar in place. For this we used a small Phillips head screwdriver. Phillips head screwdriver The bar was easily installed and tightened down.
6 Our next reassembly step was to re-solder the wires which provide power to the motor so we could operate the stapler again. To do this we used the soldering iron to melt the solder on the motor so we could reconnect the wires. Soldering iron This step was difficult because we had to be careful not to melt the plastic on the motor with the heat of the soldering iron but at the same time we had to get the solder hot enough to melt
7 Next we pushed the upper outer shell back onto middle shell so that it clipped into place. Then using a Phillips head screwdriver, we reinstalled the two screws that help hold the upper outer shell in place. Phillips head screw driver This step was very easy.
8 Then we replaced the spring and retaining clip that was located on the underside of the middle shell of the stapler. Reinstalling the spring was somewhat tricky since the spring and cir-clip are so small. For this step we used the needle nose pliers to help squeeze the cir-clip back into place while we used the flathead screwdriver to hold down the spring to keep pressure off of the cir-clip. Needle nose pliers, Flat head screwdriver Since the spring and cir-clip are so small and we needed to get two tools in a relatively small space this step was moderately difficult.
9 We then pushed the electric receiver back into its clip in the lower outer shell. We did this by spreading the two clips far enough apart for the electric receiver to be popped back in but to reinstall the receiver we did not need to separate the clips as much due to the angled surface on the clip which helped to guide the receiver into place when we pushed on it. We used our hands for this step. Hand Since less force was used to install the switch there was less of a chance that we were going to break something so this step was easier during reassembly than during disassembly.
10 Finally we replaced the lower outer shell. To do this we needed to make sure that none of the wires got pinched or interfered with the lower shell. Once all of the wires were clear however, the lower other shell was easily set into position. We then installed the four retaining screws on the bottom with a Philips head screwdriver and lastly we pushed the four rubber feet back into their recesses. Phillips head screwdriver This step was very easy.

After Assembly

The Swingline Personal Electric Stapler works as follows: when inserting a stack of papers a small trigger switch is activated which signals the circuit board to start the motor. The motor rotates a series of gears which spins a lever. The lever than moves a punch which punches a staple. As the staple punch begins to move however, it also activates a trigger switch which allows the motor to continue to spin. Once the staple punch has returned to its original position at the top of its travel, the trigger switch which the staple punch was activating returns to the open position which then stops the motor at the right position so that the stapler is always ready to staple your papers. Upon reassembly of the personal electric stapler it runs just as it did before disassembly.

The following analysis models could be used to test and/or design the Swingline Personal Electric Stapler:

  • Drop tests: To determine if the product is durable. This is more of a stress and/or fatigue based analysis. For this analysis the model would not have to be as precise since this is generally used to test the materials of the product. This is a physical model
  • FEA (finite element analysis): This is a computer based analysis of stresses on a virtual model. With this analysis the model would need to be precise since data would be put into a computer to virtually test an actual model of the poduct. This is a computer aided model mixed with a mathematical model.
  • Reverse Engineering: This is based on taking apart the product and studying its elements and parts in order to have a more detailed knowledge of the product. This is a conceptual and physical model which will hopefully help to improve upon the current product.
  • Fatigue test: This is a test to determine the limits of the product by using the product until it breaks to see how durable it is. In our case, we would have to set up some equipment to repeatedly insert a piece of paper to staple as many times as the stapler would allow us. This is a physical model which could possibly be discarded with the use of a computer model such as FEA or some form of virtual reality.
  • Overall the results of most of the tests and analytical models could be estimates because this product does not serve a complex function.

With respect to the disassembly/assembly processes; the assembly was the reverse of the disassembly. We believe this was because there was no required timing as in an engine or specific synchronizing of the parts, this way everything could just be put back as it was before. We were able to reassemble the entire product without difficulty, the difficulties we did encounter were more a matter of patience since most of the parts were very small. The reassembly was easy to do since there were very few pieces and they fit together snugly to help hold the product together in a lot of instances. We used very few tools (screw-drivers, soldering iron, pliers, and our hands). The same tools that we used to disassemble the product were used again during reassembly.

At the product level (operation, manufacturing, assembly, design, configuration, etc.), we would recommend a simpler inner system. We believe the inner core was too complex for the function it serves. Simplifying the inside system would reduce costs and make the product somewhat cheaper, or even better, and Swingline could use the money saved during assembling to choose better materials to make it more durable. This was one of the issues we found with the product. The material used to protect the inner core was a very thin plastic that could possibly break by falling off of a table and down to a tile floor which is inconvenient since this would most likely be the only scenario where you would be dropping the stapler. In regards to the shape and/or design of the products outer shell we believe it’s very plain and too simple. It doesn’t have any style or any appeal to it. We would recommend designing some form of rubber, ergonomic grip into the outer shell to help appeal to consumers; anything with more style and color. We saw other staplers that were more attractive to the eye, and they were not much more expensive than the standard model.

Other Recommendations we have are: One recommendation we would make to the Swingline company is to eliminate the circuit board. It occupies space and the function it has can be done by a simple trigger switch. Another strong recommendation we would make is to reduce the size of the outer shell and use a stronger material. In addition, we would advise them to offer different colors; this way the customer has some style options to meet their personality. The price of the product is somewhat expensive; as a result we recommend that Swingline reduce the cost of the personal electric stapler. The fact that this is a big selling product does not mean it is the best product around; there are other products which can hold more staples and staple through more pieces of paper. We believe this product sells mostly to big companies with a high volume of thin stapling jobs or busy workers. Individuals would be better off with a manual stapler since they are cheaper and more efficient because they do not cause battery waste or use electricity.

After all of our reverse engineering was applied, the Swingline personal electric stapler was still functional.

References

Swingline Personal Electric Stapler, Staples. November 29 ,2007, From http://www.staples.com/webapp/wcs/stores/servlet/StaplesProductDisplay?&langId=-1&storeId=10001&catalogId=10051&productId=19348&cmArea=SEARCH#desclink.