Rochester Institute of Technology One Lomb Memorial Drive Rochester, NY 14623-5603 David Hartmann 7980 Fall creek road, suite 105 Dublin, CA 94568 Dear Mr. Hartmann: Attached is our analysis of the TC1 fastener and its redesign for the three applications you asked us to investigate. A solution was found that is capable of operating in all three material choices: the standard lumber, the synthetic lumber, and the hardwood lumber. This was a more difficult project than some would have imagined. It was essentially redesigning the wheel. The TC1 is a terrific product that works great in standard decking lumber. Through some initial testing we found its only weakness was in the triangular spike. By refining the triangle into a more nail-like shape, the Tiger Nail was born. The following report is a complete analysis of the development of the new Tiger Nail concept. It includes an expanded definition of the existing TC1, and then a comprehensive development of ideas that we investigated along the way. Each idea had an effect on how we reached our conclusive design. We would like to thank you and Dave Martel for providing us with the opportunity to work on this project. We would also like to thank you for your guidance along the way. We have enjoyed working on the Tiger Claw and would be happy to answer any questions you may have. Sincerely, Jared Dolatowski Mike Steger Dan Willistein

Senior Design Project The Tiger Claw

Team 08F

For Tiger Claw Inc. Dr. Alan Nye

By Jared Dolatowski

Mike Steger Dan Willistein

November 14, 2002

CONTENTS Letter of Transmittal ………………………………………………………………….…i Figures …………..……………………………………………………………………...iv Abstract…………………………………………………………………………………..v Introduction……………………………………………………………………………...1

Definition and Background of the TC1..……………………………………...1 Operating Principles of the TC1 …………………..………...……….2 Installation Procedure of the TC1…………………………...……….2 Analysis of TC1 Parts……………….………………………...……….2 Comparison of the TC1 to Nails and Screws……………….……….3

Problem Statement……………………………………….…………………………….4 Constraints………….…………………………….……………………………...4 Budget………………………………….……….………………………………..4

Collected Data…………………………………………………………………..……....5 First Concept: The Deforming Spike…………………………………..……...7

Definition……….…………………………………………………….......7 Analysis and Findings……………….……………………………….....7

Interpretation of Findings……………………………………………….7 Second Concept: The Tiger Cross............…………………………………...8

Definition….………………………………………………………….......8 Analysis and Findings ……………………………………………….....9

Interpretation of Findings……………………………………………..10 Third Concept: The Tiger Nail…………………..……………………………11

Definition……………….……………………………………………….11 Analysis and Findings ………………………………………………...13 Interpretation of Findings……………………………….…………….15

Conclusions and Recommendations.…………………………………..……………16 Appendix A: Hammer Force Model…………..…………....………………………...19 Appendix B: Stress Analysis…………………..……………...……………………...20 Appendix C: Buckling Analysis………………..…………...………………………...22 Appendix D: Tiger Claw Installation Procedure…..……...………………………...24 Appendix E: Tiger Claw U.S. Patent…………………….…...………………...…...25 Appendix F: Drawing Package…………..………………...………………………...34 Works Cited…………………………………………………….………………....……41

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FIGURES Figure 1 Picture of the TC1 Hidden Deck Fastener…….……………………..…..1 Figure 2 Picture of the TC1 Installed into First Board……...…………………......2 Figure 3 Picture of a Deck with Conventional Nails……………..………………...3 Figure 4 Picture of a Deck Surface Using the TC1………………..……………....3 Figure 5 Illustration of a Triangular Spike vs. a Nail Spike………...……………..5 Figure 6 Model of the Deforming Spike……………………………………………..7 Figure 7 Model of the Tiger Cross…………………………..……………………….8 Figure 8 Installation Model with the Tiger Cross………………….………………..8 Figure 9 Model of Tiger Cross Loading Conditions……..…...…………………….9 Figure 10 Model of the Tiger Nail………………………………………………...…11 Figure 11 Installation Model with the Tiger Nail………………………………...…12 Figure 12 Model of a Butt Joint with the Tiger Nail……………..…………………12 Figure 13 Installation FEA Model of the Tiger Nail……………..…………………13 Figure 14 Warping FEA Model of the Tiger Nail………………..…………………14 Figure 15 Project Schedule……………………………………….…………………17

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ABSTRACT

Tiger Claw Incorporated is a small company based in Connecticut that has developed into a leader in the deck building industry. Their primary product is the hidden deck fastener known as the Tiger Claw #1 (TC1). The TC1 is a simple device used to install the surface of a wooden deck without the use of visible nails or screws. The fastener is relatively inexpensive, easy to install, and very strong. The current product works extremely well in standard decking, however, it is over designed. Also, the current product does not function well in synthetic lumbers or in exotic rainforest hardwoods. Tiger Claw asked team 08F to do the following: redesign the current fastener to reduce production cost, develop a fastener for use in synthetic lumber, and develop a fastener for use in exotic rainforest hardwoods. Based on our concept development, engineering analysis, and experimental testing, we determined the Tiger Nail, a variation of the TC1, is the optimum geometry to pursue. This concept will work well in standard lumber, synthetic lumber, and the hardwood lumber.

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INTRODUCTION Tiger Claw Incorporated is a small company based in Connecticut that has developed into a leader in the deck building industry. Their primary product is the hidden deck fastener known as the Tiger Claw #1 (TC1). The TC1 is a simple device used to install the surface of a wooden deck without the use of visible nails or screws. The fastener is relatively inexpensive, easy to install, and very strong. The current product works extremely well in standard decking, however, it is over designed. Also, the current product does not function well in synthetic lumbers or in exotic rainforest hardwoods. Tiger Claw asked team 08F to do the following: redesign the current fastener to reduce production cost, develop a fastener for use in synthetic lumber, and develop a fastener for use in exotic rainforest hardwoods. This report is written for Tiger Claw and Dr. Alan Nye. Its intent is to inform the viewing parties of our recommendations for the solutions to the tasks assigned and to justify these recommendations through engineering analyses. Definition and Background of the TC1 The TC1 hidden deck fastener is a simple device used to install the surface of a wooden deck without the use of visible nails or screws. The use of this product results in a smooth deck surface. The owners of Tiger Claw initially drew the current design on a bar room napkin. It was designed to work well, be easy to install, and be very strong. However, the design was not optimized to reduce the amount of material used in the part. The existing TC1 fastener can be seen in figure 1 below.

Figure 1: Picture of the TC1 hidden deck

fastener. (Tiger Claw Inc.)

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Operating Principles of the TC1 The current TC1 design securely attaches decking boards by holding the edges of the boards, rather than screwing or nailing through the top. This leaves the fastener virtually invisible. The fastener is then attached to the supporting member below the surface with a common decking screw. Once securely screwed down, the next board is hammered into the protruding spikes. These spikes are from the backside of the fastener which was already installed into the previous board. To see how it is applied see figure 2 below.

Figure 2: Picture of the TC1 installed into first board and

screwed down into the supporting joist. Installation Procedure Installing the fastener requires the use of a wooden installation block. It is a very simple process. The instructions provided by Tiger Claw are attached in Appendix D. Analysis of TC1 Parts The TC1 is easily manufactured out of half hard 1010 cold rolled steel on a progressive die. The resulting part costs only $0.05 to make. Tiger Claw Incorporated then sells the fasteners in a box of 100 parts for $39.95.

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Comparison of the TC1 to Nails and Screws

When compared to nails and screws, Tiger Claw fasteners have the following advantages:

�� Tiger Claw fasteners are virtually invisible. �� Tiger Claw fasteners reduce the potential for wood rot (which can begin

around the head of screws and nails). �� Tiger Claw fasteners eliminate splits at ends of boards caused by screws

and nails (see figure 3 below). �� Tiger Claw fasteners give a deck a smooth professional appearance (see

figure 4 below). �� Tiger Claw fasteners reduce cupping because they hold deck boards from

the edges. �� Tiger Claw fasteners do not restrict decking when boards shrink so wood

splitting is not a problem. �� Tiger Claw fasteners do not damage the decking surface during

installation. �� Tiger Claw fasteners have more surface area holding the decking down

than screws or nails. �� Tiger Claw fasteners create a nail-free surface which is easier to maintain. �� Tiger Claw fasteners do not corrode, so the deck surface isn't stained. �� Tiger Claw fasteners extend the life of a deck, and reducing long-term

ownership costs

Figure 3: Picture of a deck with conventional Figure 4: Picture of a deck surface nails. (Deck One Inc.) using the TC1.

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PROBLEM STATEMENT The TC1 functions extremely well in standard decking materials, however, Tiger Claw would like to improve it. They would also like to expand their company’s influence into other aspects of the deck building industry, such as in decks built out of synthetic lumbers or exotic rainforest hardwoods. The TC1 pulls out of the synthetic lumber very easily and splits the hardwood. So they proposed the following three projects:

1) Redesign the current TC1 to reduce production costs 2) Develop a hidden deck fastener for use in synthetic lumbers 3) Develop a hidden deck fastener for use in exotic rainforest hardwoods.

Constraints The constraints for the projects are as follows:

�� The solution for project # 1 must be strong, easy to install, and cost less than $0.05 per part to produce.

�� The solution for project # 2 must be strong, easy to install, and relatively inexpensive.

�� The solution for project # 3 must be strong, easy to install, and relatively inexpensive.

�� The cost of retooling is not within the scope of this project. Note: Though not a necessity, using the same fastener for all three applications would be ideal. Budget A budget of up to $1000.00 was allotted by Tiger Claw for this project. This figure includes testing of concepts, and fabrication of working prototypes.

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COLLECTED DATA The existing TC1 fastener is a terrific product. It functions well with standard decking lumber, the material for which it was designed. The TC1 even functions well in less than ideal deck building situations. This means it can handle the added stresses of warped boards and off center hits of a hammer. However, the TC1 does have weaknesses in synthetic lumber and in rainforest hardwoods. The design is weak because of its triangular spike and its overall thickness. The triangular spike of the TC1 makes installation easy, but an installed fastener can be wiggled out of its secure position by hand. This situation occurs in standard lumber, but is more prominent in synthetic lumber. Synthetic lumber has an interesting mechanical property; once it is deformed it stays that way. The lumber does not form around the spike when it is installed, hence making the fastener extremely easy to pull out. In general, lumber has the tendency to shrink and expand depending on temperature and length of environmental exposure. Over time, this could have the effect of changing the position of the spike as shown in figure 5. The top row of pictures shows a triangular spike and a nail type spike fully inserted into the lumber, shown in red. If the triangular spike moves outward even a small amount, the entire length of the spike loses contact with the lumber. This diminishes the integrity of the deck, both in strength and in safety. However, if the nail type spike moves outward, there is still a large amount of surface area in contact with the lumber. This contact maintains the integrity of the deck.

Figure 5: Illustration of a triangular spike vs. a nail spike.

The existing fastener splits hardwoods when it is installed. This is because the fastener material is too thick to pierce the dense surface of the hardwood easily.

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Modeling and testing resulted in the development of three main concepts:

�� The Deforming Spike �� The Tiger Cross �� The Tiger Nail

Each concept was drawn in Pro Engineer, and then a rough prototype was manufactured. If the prototype proved itself useful, the concept was drawn in IDEAS where Finite Element Analysis (FEA) was done. This analysis was used to determine if the fastener would buckle during the installation procedure. The FEA model revealed the locations of maximum stress experienced by the fastener is during installation. This stress must be less than the yield stress of the material. As a worst-case scenario, the fasteners were modeled as if being hit into a brick wall by the force of a hammer (See Appendix A). This method of analysis was chosen because the loading on the spike changes as it pierces through the wood’s surface, and RIT does not have the necessary software to create a dynamically loaded model.

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First Concept: The Deforming Spike

Definition The Deforming Spike would take the place of the spikes on the existing fastener. It would plastically deform upon insertion, thereby trapping material within itself. The trapped material would anchor the fastener into the board. It is installed by the same procedure as the TC1. The preliminary design can be seen in figure 6 below.

Figure 6: Model of the Deforming Spike.

Analysis and Findings A preliminary rough prototype of the Deforming Spike was made. The spike worked great in standard lumber; it trapped material and was very difficult to remove. However, it did not function as well as anticipated in the synthetic lumber. The spike plastically deformed when it was inserted and trapped material, but it pulled out easily. No FEA modeling was done on this design since the prototype proved the design would not work. The trapped material did not increase the holding power of the fastener because the spike sheared the material off. Interpretations of Findings Since the prototype proved that this design would not work, the concept was not pursued any further. It was also determined that this design would be very expensive to manufacture. The intricate design has many sharp corners that would reduce the life of the stamping die. A decrease in die life equates to a large increase in manufacturing costs.

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Second Concept: The Tiger Cross

Definition The Tiger Cross is a very simple design. It is a double-sided nail that is very small, thin, strong, and easily manufactured. The existing TC1 fastener can be removed easily because of its triangular spike design. This design is more like a nail or staple which has an increased amount of fastener surface area in contact with the wood. The neck sets the gap between the decking boards and adds rigidity during installation. The concept can be seen in figure 7. The design attaches decking boards in the same fashion as the TC1, but is attached to the side of the joist using a standard decking screw, rather than to the top. Figure 8 shows a model of a section of deck with the deck boards transparent for viewing purposes. The fastener for the standard decking and the synthetic lumber would use 1010 half-hard cold rolled steel at a thickness of 0.0625 inches. The fastener for the hardwood lumber would use 301 full-hard stainless steel at a thickness of 0.030 inches. These materials were chosen in order to minimize production costs and to optimize the fasteners function.

Figure 7: Model of the Tiger Cross.

Figure 8: Installation model with the Tiger Cross.

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Analysis and Findings The loading conditions on the Tiger Cross allow analytical calculations of stress and buckling to be performed. The loading conditions are shown in figure 9. The force to install is distributed over the shaft of the fastener.

Figure 9: Model of Tiger Cross

loading conditions.

As stated previously, the materials were chosen in order to minimize production costs and to optimize the fasteners function. This determination was based on recommendations from Tiger Claw. Material properties can be found in Appendix B. The installation block used to install this fastener would be designed to support the shaft of the fastener along its length. Using these assumptions the spike can then be modeled as a cantilevered beam subject to a compressive force. The calculations of the critical load required to yield the spike and to buckle the spike can be found in Appendices B and C respectively. It was found that a spike with a width of .125 inches made out of 1010 cold rolled steel (.0625 inches thick) would take a force of 247 lbf in order to compressively yield the spike, and a force of 4550 lbf in order to buckle the spike. The reason for the large difference between these forces is due to the short length of the spike, 0.5 inches. Knowing that the force applied by the hammer is 224 lbf (Appendix A), the spike will not fail during installation. It was found that a spike with a width of .125 inches made out of 301 full-hard stainless steel (.030 inches thick) would take a force of 375 lbf in order to compressively yield the spike, and a force of 486 lbf in order to buckle the spike. Knowing that the force applied by the hammer is 224 lbf (Appendix A), the spike will not fail during installation.

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Based on this information, a prototype was developed as a proof of concept. The prototyping proved that the holding power of this fastener was great in both regular lumber and synthetic, but problems arose in the hardwoods. Due to the density of the lumber, multiple hits were necessary to install the fastener. This essentially work hardened the fastener, and thus failure occurred. The solution to this problem is to make the fastener for hardwoods out of a thinner and harder material. Interpretations of Findings Analysis and experimental testing proved that this fastener was physically strong, and would work well if it could be installed. Tiger Claw also felt the design would work, however, the design is very difficult to market. Tiger Claw has an image of producing very strong parts, both physically and visually, and would like to maintain this marketing edge. The installation block would have to be designed such that the loading conditions were symmetric about the spike. If the load was not symmetric, the loading would be skewed and the spike would bend. Due to the drawbacks of marketing the Tiger Cross, it was determined not to pursue this concept any further.

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Third Concept: Tiger Nail

Definition The Tiger Nail design is virtually identical to the existing TC1, although its spikes are straight rather than triangular. This increases the amount of fastener surface area in contact with the wood (figure 5). This design is a result of combining the existing TC1’s visual strength with the holding strength of the Tiger Cross. The initial design concept can be found in figure 10.

Figure 10: Model of the Tiger Nail.

The four main spikes are 0.5 inches long, 0.125 inches wide, and the thickness is dependent on application. The overall length of the fastener is 1.75 inches. The fastener for the standard decking and the synthetic lumber would use 1010 half-hard cold-rolled steel at a thickness of 0.0625 inches. The fastener for the hardwood lumber would use 301 full-hard stainless steel at a thickness of 0.030 inches. The spikes on the bottom of the fastener were retained from the original TC1 fastener after experimentation with the fastener revealed that they help stabilize the fastener during installation. However, they were modified to reduce the number of sharp edges in order to maximize die life. The installation procedure would be the same as the pre-existing TC1 fastener as shown in Appendix D. A computer model of a deck was created in order to quickly test this concept for its installation ease. This model can be found in figure 11.

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Figure 11: Installation model with Tiger Nail.

In the event that a butt-end-joint needs to be constructed, the fastener would need to be installed backwards. This concept is shown in figure 12. The deck boards have been made transparent to make viewing easier.

Figure 12: Model of a butt joint with the Tiger Nail.

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Analysis and Findings: Two FEA models were created of the Tiger Nail. The first model was a worst-case installation scenario in which the fastener was essentially driven into a rigid board. The second model was of a failure mode in which the prongs were driven upward, simulating warping of a deck board. Material properties that were used in the FEA analysis can be found in Appendix B. The installation model is shown in figure 13 below. The boundary conditions were applied to simulate the use of an installation block with the force distributed on the flange of the fastener. The ends of the spikes were constrained in all directions to model the spikes digging into the board. The bottom of the fastener was not allowed to move downward in order to simulate the presence of a joist. It was found that the maximum stress was 339 ksi. This value is an order of magnitude higher than the yield stress of the 1010 steel used in the model. If the fastener geometry were optimized to handle this loading condition, the fastener would be extremely over designed. The yield strength of the lumber is on average an order of magnitude less than the yield strength of the metal. Therefore, the lumber would deform before this condition could arise. The FEA model was used in a qualitative sense to determine locations of high stress areas.

Flange

Figure 13: Installation FEA model of the Tiger Nail.

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Due to the fact that the stresses found in the installation FEA model could not be used, experimental testing was employed to determine the optimum geometry. The locations of the high stress areas found in the FEA analysis were used to develop the initial prototype. Different length spikes, as well as different width spikes, were evaluated to find the optimum values. For all three varieties of decking, it was found that the length of the spike should be 0.5 inches long and 0.125 inches in width. The second FEA model was of a possible failure mode of the fastener using the optimized geometry found experimentally. This model is shown in figure 14. The model simulates the stresses induced due to the warping of the deck boards. The applied force is distributed over the entire length of the spikes as if it were fully installed into two deck boards. The boundary conditions simulate a rigid connection to the joist. It would require a load of 66 lbf distributed over the spikes to cause failure in this mode.

Figure 14: Warping FEA model of the Tiger Nail.

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Interpretations of Findings Analysis and experimental testing proved that this fastener was physically strong enough to handle installation and strong warping forces. This fastener also has the visual appeal necessary for marketing value. The Tiger Nail provides direct connection of the decking boards to the supporting joist below, through the use of a standard decking screw. This provides the necessary rigidity to overcome any force due to warping.

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CONCLUSIONS AND RECOMMENDATIONS Based on our concept development, engineering analysis, and experimental testing, we determined the Tiger Nail is the optimum geometry to pursue. This concept will work well in standard lumber, synthetic lumber, and the hardwood lumber. The project description provided by Tiger Claw states that the redesign of the current TC1 fastener for standard lumber must reduce production costs. The Tiger Nail achieves this goal in two ways. The first is a reduction in the overall length of the fastener by over 0.25 inches per part. This will allow the manufacturer to buy a smaller width of raw material, which in turn reduces the material cost per part. The second way the Tiger Nail reduces production costs is by using the same die to stamp the fastener for both standard and synthetic lumbers. This allows Tiger Claw to have one die to manufacture the majority of their fasteners. These savings will be seen in the long run manufacturing costs. The fastener should be produced out of 0.0625-inch thick 1010 half-hard cold rolled steel. As was stated previously, the same fastener used for standard lumber will be used for synthetic lumber. This satisfies the objective of the second project provided, which was to develop a hidden deck fastener for use in synthetic lumber. It is estimated that synthetic lumber accounts for 8% of the lumber used in deck building. The Tiger Nail will effectively corner this market because it is one of the few commercially available fasteners that is physically strong and cost effective. The fastener should be produced out of 0.0625-inch thick 1010 half-hard cold rolled steel. The same geometry will be used to satisfy the third project of developing a fastener for use in exotic rainforest hardwoods. The only difference will be the material and the material thickness. In this case, 0.030 inch thick 301 full-hard stainless steel will be used. Detailed part drawings have been attached in Appendix F. Tiger Claw Incorporated has determined what part names will be. The redesigned fastener for standard lumber will retain its TC1 designation, the synthetic lumber fastener will be known as the TC3, and the hardwood lumber fastener will be known as the TC4. Each fastener has two drawings. The first drawing is a part drawing after the forming process has been complete, and the second drawing is a flat pattern of the part. For prototyping, a laser cutting process and hand forming process will be implemented. The flat pattern drawing provides the person doing the folding information as to what directions the prongs are bent and to what degree.

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The Tiger Nail may still fall under the original patent issued to Tiger Claw Incorporated. The original patent is attached as Appendix E. Further investigation is needed to determine whether or not a new patent will be needed. Tiger Claw allotted a budget of $1000. This budget includes the costs of prototype manufacturing and all testing supplies. Expected expenses are as follows:

�� Laser cut parts…….$600 �� Wood material…….$40 �� Total expenses……$640

A schedule has been developed for the next 6 months. This schedule is shown below in figure 15. As you can see, we have completed everything that we set out to accomplish in fall quarter. Having parts laser cut requires a long lead-time, and therefore prototypes will be fabricated during winter quarter. Spring quarter is reserved for testing and redesign. Preliminary testing procedures are currently being evaluated. The testing presented in the schedule states that we will be doing deconstructive testing. This will take place in two failure modes. First, a small section of deck will be constructed out of various material under ideal conditions. This means that each fastener will be installed exactly as specified in Tiger Claw’s instructions (Appendix D), then pulled apart using the tensile testing machine to find the force required. The second mode of failure is if the contractor installing the deck forgets to, or chooses not to, install the screw required for proper installation. The same deconstructive test will be implemented to test performance and correlate to safety.

ID Task Name September October November December January February March April May1 Senior Design Project2 FALL QUARTER3 Choose Project4 Determine Constraints5 Investigate Current Design6 Research Artificial Lumber7 Write Requirements Document8 Prepare Presentation9 Project and Constraint Presentation10 Choose Concept11 Detailed Design and Analysis12 Prepare Presentation13 Formal Concept Presentation14 WINTER QUARTER15 Part Fabrication16 SPRING QUARTER17 Finish Part Fabrication18 Determine Testing Procedures19 Prepare Presentation20 Construct Model Deck for Destructive Testing(3)21 Construct Model Deck for Presentation22 Deconstructively Test Decks23 Prepare Presentation24 Prepare Final Report

Senior Design Project Schedule

Figure 15: Project Schedule.

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During our preliminary prototyping and testing, it was found that the installation block failed after installing a number of fasteners. The installation block was not specifically mentioned in the scope of these projects, but it is recommended that the installation block be investigated for a possible redesign.

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APPENDIX A An explanation of the force due to a hammer used in the FEA models: An experiment was conducted to determine the average force that would be applied to the fastener during installation. A simple impulse momentum experiment was created in which a nail was driven into a sample of wood. The mass of the hammer used was 0.5 kg and the length of the path of the hammer head was .5 m. The velocity of the swing was assumed to be constant over this .5 m path. With a stopwatch it was found that on average it took 0.1 seconds to cover this path. Therefore the average starting velocity was 5 m/s. The final velocity of the hammer will be 0 m/s. In order to complete the analysis, the time in which the hammer is in contact with the nail must be known. It was found that the time of contact is approximately 5 ms (Physics).

MdvFdt � )50)(5.0(sec)005.0( s

ms

mkgF �� lbfNF 112500 ����

This is actually the reaction force of the nail on the hammer, and that is the reason that the force is negative. Assuming that this is the average force, and applying a factor of safety of 2, all analysis will be formulated on an average force of 224 lbf.

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APPENDIX B Stress calculations:

P

Cross Section

b

h

kAPcritical

�

�

This is the force that would cause a compressive failure of the spike. P is the applied force � is the stress induced in the spike by the load. In this case, the valuebe the yield stress A is the cross sectional area of the spike K is the stress concentration factor for a filleted beam For the TC1 and TC3, the spike has dimensions of .125” X 0.0625”. For the TC4, the spike has dimensions of .125” X 0.030” The stress concentration factor, k, is 1.4 (Hamrock). Material Properties:

Material(steel)

Yield Strength

(ksi)

Modulus of Elasticity

(ksi)Density(slug/ft3)

301 Stainless Full Hard 140 28.0 x 103 15.29

1010 Cold Rolled 44.2 29.0 x 103 15.23

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used will

TC1 and TC3 analysis: The following analysis is for 1010 cold rolled steel.

4.1)0625.*125)(.44237( inchesinchespsiPcritical �

lbfPcritical 247�

Hammer Force = 112 lbf

Hammer Force * (Factor of Saftey = 2) = 224 lbf

If, Hammer Force is < 247 lbf, then spike will yield

224 lbf < 247 lbf

Therefore, the spike will not yield due to an exaggerated hammer blow. TC4 analysis: The following analysis is for 301 full hard stainless steel.

4.1)030.*125)(.140000( inchesinchespsiPcritical �

lbfPcritical 375�

Hammer Force = 112 lbf

Hammer Force * (Factor of Safety = 2) = 224 lbf

If, Hammer Force is < 375 lbf, then spike will yield

224 lbf < 375 lbf

Therefore, the spike will not yield due to an exaggerated hammer blow.

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APPENDIX C

Buckling Analysis

bh

Cross Section

P L=0.5 inches

2

22

effectivecritical L

EICP �

�

Pcritical is the loading that will cause buckling of the column C is a constant determined by the loading and boundary conditions. For our case a value of 1 will be used (Hamrock). E is the modulus of elasticity of the material I is the moment of inertia of the cross section (I=1/12bh3) Leffective is the effective length of the column. Our boundary conditions are described as one end fixed and one end pinned, therefore Leffective is 0.8*L (Hamrock). For the TC1 and TC3, the spike has dimensions of .125” X 0.0625”. For the TC4, the spike has dimensions of .125” X 0.030” Material properties can be found in Appendix B. TC1 and TC3 analysis: The following analysis is for 1010 cold rolled steel.

� � � �

� �2

32

5.*8.0

0625.* 125.*121 29007548

inches

inchesinchespsiPcritical

��

���

�

�

�

lbfPcritical 4550 �

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Hammer Force = 112 lbf

Hammer Force * (Factor of Safety = 2) = 224 lbf

If, Hammer Force is > 4550 lbf, then spike will buckle

224 lbf < 4550 lbf

Therefore, the spike will not buckle due to an exaggerated hammer blow.

TC4 analysis: The following analysis is for 301 full hard stainless steel.

� � � �

� �2

32

5.*8.0

030.* 125.*121 80000002

inches

inchesinchespsiPcritical

��

���

�

�

�

lbfPcritical 486 �

Hammer Force = 112 lbf

Hammer Force * (Factor of Saftey = 2) = 224 lbf

If, Hammer Force is > 486 lbf, then spike will buckle

486 lbf > 224 lbf

Therefore, the spike will not buckle.

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Appendix D

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Appendix E

Tiger Claw US Patent

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Appendix F

Drawing Package

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-39-

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WORKS CITED Callister, William. Materials Science and Engineering. USA: Wiley and Sons,

1999. Deck One, 26 October 2002. www.deckone.com. Hamrock, Bernard, J., et al. Fundamentals of Machine Elements. New York:

McGraw-Hill, 1999. Physics Department, University of Maryland. 11 November 2002.

www.inform.umd.edu/EdRes/Colleges/CMPS/Depts/Physics/Courses/PHYS410/spring2001/Apr15.html

Tiger Claw Incorporated, 26 October 2002. www.deckfastener.com.

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