Group 23 - Swingline Electric Stapler

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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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.
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.
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.
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.
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
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.
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.
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.
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
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	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
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
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
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
5	Wires	Copper - Very good conductor of electricity, Plastic - To insulate	Machining	Transfers electricity	Flexible, thin, white, red, green, blue, black, and yellow	13
6	Motor	Plastic - Electrical insulation, Steel - To withstand vibration and other stresses	Metal Casting	To rotate gears	Small, powerful, silver, and mostly round	1
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
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
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
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
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
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
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
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
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
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

The shape of the components can’t really be changed. They look that way because that’s the way they are designed. However, there were some components which had a specific size to enhance their function. There was a lever that had a specific shape and was composed out of metal. This lever takes the rotational force of the gears and transforms it into vertical force. We think this component looks that way because the geometry of it helps to take the rotational force of the motor into vertical force. This is the force that is used to punch the staple through the papers. We know the gears had to be round since the force originated is rotational. Gears are perfect for driving rotational force. The staple tray is cubed because this is the best shape is to hold and fit staples. Overall, the relation that most components have is that they are small. We believe most of the components are small in order to reduce the size of the stapler itself.

We would suggest the following changes/improvements should be taken in consideration:

• Less wiring: The wiring for the inner circuit was too long. It was in our way when we needed to unscrew and screw as well.
• The materials used were mostly plastic which doesn’t give the stapler a strong structure. Even though this stapler is bigger and has more components than a mechanical stapler, it’s somewhat lighter. This indicates that the durability is not that good. We would have used
• Fewer gears: Although the gears are needed, they could have engineered two to three gears to certain size and obtain the same result with less gears. That would save some cost.
• One size screw fit for all: There were different sizes of screws so when it came to reassembly we had to figure out by guessing, to some extent, where would each screw go.
• The size of the stapler was quite big. We think that it’s possible to reduce the size of the stapler. The interior had open spaces that weren’t used at all.

• CAD file for selected parts

Assembly

Process

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.	Solder	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	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 it follows: the paper triggers a switch that signals the circuit board to turn the motor on. The motor rotates a series of gears that trips a lever that punches a staple. The product does run as it did before disassembly

The following models analyses 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 wouldn’t have to be as precise since this is generally used to test the materials of the product. This is mostly 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 have an actual product. This is a computer aided model mixed with 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 model.
• Fatigue test: This is based on using the product until it breaks to see how durable it is. In our case, we would staple as many times as the stapler would allow us. This is more of a physical model.
• Overall the analyses models could be estimates because this product does not have 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 little synchronizing of the parts so everything could just be back as it was before. We were able to reassemble the entire product. This was easy to do since there were very few pieces that would hold the whole product together. We used very few tools (screw-drivers, solder, pliers and hands). We used the same tools that we used to disassemble were used to reassemble. It was more a matter of patience since most parts were very small.

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 had. Simplifying the inside system would reduce costs and make the product somewhat cheaper, or even better, use the saved money in assembling better materials to make it more durable. This was one of the issues we found on the product. The material used to protect the inner casing was a very thin plastic that could break just by falling off from a table down to a tile floor. In remarks to the shape and/or design of the product we believe it’s very vague and too simple. It doesn’t have any style or any appeal to it. We would recommend a better design. Something with more style and color. We saw more staplers that were more attractive to the eye, but they were obviously more expensive.

Some recommendations we would suggest 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. Also reduce the size of the outer shell and using a stronger material. In addition, we advise to offer different colors, that way the customer has a little style selection. The price of the product is somewhat expensive; in consequence we recommend to reduce costs. The fact that this is a big selling product does not mean it is the best product around. We believe this product sells mostly to big companies. Individuals would be better off with a manual stapler. It’s cheaper and more efficient to some extent.

After all the reverse engineering applied, the Electric Personal 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.