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Authors: Yeh-Liang Hsu, Po-Er Hsu, Yung-Chieh Hung, Ya-Dan Xiao (2010-04-30)recommend: Yeh-Liang Hsu (2010-08-24).
Note: This paper is presented at the ASME 2010 International Design Engineering Technical Conferences (IDETC), Montreal, Quebec, Canada, August 2010.

Development and application of a patent-based design around process

Abstract

Patent infringements have become an important issue for industries when developing products. Designing around existing patents of competitors is a task constantly faced by designers. New design problems, which are often a local innovation of an existing patent, are generated during the design-around process. The rules of patent infringement judgment present the major constraints to such design problems, and designers may have to sacrifice performance of the product in order not to infringe on existing patents. This research proposes a patent-based design process by systematically integrating patent information, the rules of patent infringement judgment, strategies of designing around patents, and innovative design methodologies. The purpose of the process is to generate a new design concept that is a slight variation of one of the concerned patents but does not infringe on existing patents. The basic idea is to consider the design structure that will avoid patent infringement before engineering design concepts are actually generated.

In this process, first the designer conducts standard patent analysis to identify the related patents to be designed around. Each patent is then symbolized by a “design matrix” converted from the technology/function matrix of the patent. A design-around algorithm is developed to generate a new design matrix that does not infringe on design matrices of existing patents. Then the new design matrix is transformed back into a real engineering design using the “contradiction matrix” in Theory of Inventive Problem Solving (TRIZ). This design process aims to assist enterprises to enhance the efficiency of product development, lower the possibility of patent infringements, and increase the potential to patent results of innovation. A computerized design-around tool for this patent-based design process is also developed. Two design-around examples are used to demonstrate this process and the computerized design-around tool.

Keywords: design process, design around, patent analysis, patent infringement

1.     Introduction

Design process plays an important role in the success of a product’s development. Systematic product design processes commonly seen in research literature or design textbooks often start with finding a need, specification development, conceptual design, detail design, and finally production. Such design processes are very useful for innovative design. Innovative design methodologies such as analogy, brain storming, and Theory of Inventive Problem Solving (TRIZ) are often used to generate engineering design solutions.

However, the design problem constantly faced by engineering designers across industries is how to design around existing patents [Glazier, 1990], which requires a completely different design approach and knowledge. This type of design problem is often a local innovation of an existing patent. The rules of patent infringement judgment present the major constraints to such design problems, and designers may have to sacrifice performance of the product in order not to infringe on existing patents.

Although patent analysis has almost been a standard process in the early stage of product development in industry, few researches in design processes consider competition or constraints in the form of existing patents and fully utilized the information obtained from patent analysis. Chen and Chen [2004] integrated the systematic design process and design patent protection mechanism to develop an adaptive design process. Zhang and Chen [2004] presented a process based upon the extension theory and TRIZ to design around patents and resolve conflictive problems. Chang et al. [2004] proposed an auxiliary methodology for creative mechanism design. This methodology is a systematic approach based on modification of existing devices for the generation of all possible topological structures of mechanisms to avoid existing designs that have patent protection. Hung and Hsu [2007] described an integrated process for designing around existing patents through TRIZ.

Designing around is based on the process and rules of patent infringement judgment to develop a design that has substantial difference in the scope of claims of existing patents. Designing around techniques have been discussed in many textbooks. For example, Nydegger and Richards [2000] proposed three possible strategies for designing around an existing patent:

(1)      Reduce the number of elements in the claims to satisfy the full elements rule.

(2)      Use the method of substitution to make the accused subject matter different from the techniques disclosed in the claims to prevent literal infringements.

(3)      Substantially change one of the constitutive requirements of way/function/result to prevent infringements according to the doctrine of equivalents.

These designing around techniques provide a good guideline for avoiding patent infringement. Note that each of the methods described above, reduce the number of elements, substitution, or change one of the constitutive requirements, presents a new design problem to be solved. Innovative design methodologies are still needed to generate real engineering solutions for the new design problems.

This research proposes a patent-based design process by systematically integrating patent information, rules of patent infringement judgment, strategies of designing around patents, and innovative design methodologies. Instead of generating a completely innovative design, the purpose of the process is to generate a new design concept that is a local variation of one of the concerned patents but does not infringe on existing patents. The basic idea is to consider the design structure that will avoid patent infringement before engineering design concepts are actually generated.

Figure 1 shows the conceptual flowchart of this patent-based design process. To start with, the designer conducts standard patent search and analysis to identify the patents to be designed around and to collect functions and core techniques of each concerned patent. Each concerned patent is then symbolized by a “design matrix” converted from the the technology/function matrix of the patent to represent its design structure from patent point of view. This design matrix representation is inspired by the Axiomatic Design (AD) methodology developed by Suh [2001], which uses matrix methods to systematically analyze the transformation of customer needs into functional requirements, design parameters, and process variables. AD has received great attention from engineering designers in recent years, and have been widely applied in various engineering design applications. Cebi and Kahraman [2010] made a comprehensive literature survey on AD principles covering 63 papers.

The design matrices representing the patents can be manipulated mathematically. Rules of infringement judgment and design around strategies are converted into mathematical operators applying on the design matrices. In this research, a design-around algorithm is developed to generate a new design matrix that does not infringe on design matrices of concerned patents. There can be many design matrices that satisfy the constraints. In our algorithm, the design matrix which is the smallest variation of one of the design matrices of concerned patents to be designed around will be chosen first. The new design represented by this design matrix will also be a local variation of a concerned patent. Finally, TRIZ is used to transform this new design matrix back into a real engineering design, knowing that the new design will not infringe on the concerned patents.

The whole process is integrated into a computerized “Design-Around Tool (DAT)”. By defining the technology/function matrix of the patent to be designed-around in DAT, the designer can conveniently obtain a series of design problems to be solved, sorted by the extent of variation to the existing patent.

Figure 1. Conceptual flowchart of the patent-based design process.

TRIZ is a systematic approach to finding innovative solutions to technical problems which was put forward by a former Soviet Union scientist Altshuller. TRIZ is an available tool for design engineers to handle conflict conditions during the innovation design problem solving process. There are several methods in the TRIZ toolset [Altshuller, 1998]:

Ÿ      Ideality

Ÿ      Contradiction Matrix

Ÿ      Physical Contradiction Resolution Principles

Ÿ      Substance Field (Su-Field) Analysis

In this research, the Contradiction Matrix is mainly used to convert the new design matrix into an engineering design solution. However, this transformation may fail because there may not be a feasible engineering design corresponding to the new design matrix generated by the algorithm. Referring to Figure 1, if TRIZ fails to generate a feasible design, the algorithm is triggered again to generate the next design matrix which satisfies the patient infringement constraints and is the smallest variation of one of the design matrices of the concerned patents. Finally, one or more new design concepts are generated.

The rest of the paper is organized as follows. In Section 2, a portable magnetic impact tool design problem, which will be used to illustrate the patent-based design methodology throughout this paper, is described first. Section 3 discusses how the related patents obtained from patent analysis are symbolized using the concept derived from Axiomatic Design. Section 4 and 5 discuss the development of the design-around algorithm and the integration with TRIZ to generate the real engineering design concept. The portable magnetic impact tool design example is used again to illustrate the detailed steps of implementation. Section 6 presents a computerized “Design-Around Tool (DAT)” based on the innovative patent-based design process. Another example, the design-around problem of a golf club head with weight adjustment, is solved using DAT. Finally Section 7 concludes the paper.

2.     The portable magnetic impact tool design problem

Portable power tools used for drilling and fastening are expected to be relatively small and light, yet providing high power to perform the desired functions. Figure 2 shows the major components of a portable power tool driven by an electric motor. The rotational motion of the motor is transmitted to a chuck that holds a tool output shaft by means of a hammer. The motor is generally small due to restrictions imposed on the overall size and weight of the portable power tools. Limited power of the small motor might not be enough to drive the intended load. A hammer type of mechanism is used to generate high output torque from a small drive.

Figure 2. Components of a portable power tool

As shown in Figure 3, the hammer stores the rotational energy of the motor over a large angle of rotation, for example, a half turn. Then the hammer hits the chuck to create an impact torque over a small angle (for example 10 degrees) of rotation of the chuck. In this type of portable power tool, loud noise is generated when the hammer hits the chucks. To eliminate the hammering noise, some patents have proposed the concept of a magnetic impact tool with which screws are tightened using magnetic coupling to deliver a strike without any contact. Therefore a tightening rotational impact force can be obtained without a collision sound.

Figure 3. Top view of a hammer type impact generator

One successful example of a magnetic impact tool is disclosed in U.S. Patent 6,918,449, granted to Shinagawa et al. [2005]. As shown in Figure 4, the magnetic impact tool comprises a magnetic hammer driven by a motor, a magnetic anvil disposed so as to face the magnetic hammer, and an output shaft that rotates together with the magnetic anvil. The magnetic hammer is movable with respect to the magnetic anvil without contact.

A rotational impact force is magnetically generated in a non-contact manner for the magnetic anvil in conjunction with the rotation of the magnetic hammer. During the screw-tightening work, the magnetic hammer and magnetic anvil begin to rotate together without any impact action when the load torque is initially low. When the load torque exceeds the magnetic attraction torque, the magnetic hammer and magnetic anvil are not synchronized anymore. Impact action can be generated, and screw tightening and loosening work can be carried out even if a low-torque motor is used.

Figure 4. U.S. Patent 6,918,449

The torque generated between the magnetic hammer and magnetic anvil can be changed by the changing device to vary the distribution ratio of the magnetic flux from the magnetic hammer to the magnetic anvil. As shown in Figure 4, there is a magnetic bypass device for distributing magnetic flux between the magnetic anvil and the magnetic hammer. There is also a changing device for changing the distribution of magnetic flux. The changing device comprises a micromotor (25a), a worm gear (25b) and pinion gear (25d). The pinion gear is mounted on the external peripheral surface of the bypass device (24a). The bypass device can be moved in a reciprocating manner in the axial direction of the drive shaft by driving the micromotor. Thus, the distribution of magnetic flux between the magnetic hammer and magnetic anvil can be changed. A switch for controlling the operation of the micromotor may be provided separately.

In patent analysis, the technology/function matrix is used to investigate which techniques can produce the specific functions. The column of the matrix represents the functions while the row lists the disclosed techniques. The technologies and functions are obtained from the patent abstract lists of each concerned patent. After standard patent search and analysis, two other related patents, JP 09,254,046 and JP 2004,291,136, which achieve the same 4 functions “tighten/loosen screw”, “generate impact torque” and “change magnetic flux” were identified. Table 1 to 3 shows the technology/function matrices of the 3 patents to be designed around.

Table 1. Technology/function matrix of U.S. Patent 6,918,449

           Functions

Technologies

Tighten/ loosen screw

Generate impact torque

Change magnetic flux

Motor

 

Magnetic hammer

 

Magnetic anvil

 

Drive shaft

 

Output shaft

 

 

Magnetic bypass device

 

 

Changing device

 

 

Table 2. Technology/function matrix of JP 09,254,046

           Functions

Technologies

Tighten/ loosen screw

Generate impact torque

Change magnetic flux

Motor

 

Electromagnetic clutch

Output shaft

 

 

Reducer

 

 

Table 3. Technology/function matrix of JP 2004,291,136

           Functions

Technologies

Tighten/ loosen screw

Generate impact torque

Change magnetic flux

Motor

 

Drive shaft

 

Magnetic hammer

 

Magnetic anvil

 

Output shaft

 

 

Gap changing means

 

 

3.     Design matrix representation

In this research, each concerned patent in the technology/function matrix is symbolized by a design matrix, which is inspired by the Axiomatic Design methodology proposed by Suh [2001].

Axiomatic design is a system design methodology using matrix method to analyze the transformation of customer needs into functional requirements, design parameters, and process variables. The axiomatic design approach consists of two axioms. Axiom 1, which is called the independence axiom, deals with the relationship between functional requirements (FRs) and design parameters (DPs). Axiom 2, which is called the information axiom, deals with the complexity of the design.

In this research, Axiom 1 is used for representing each patent to be designed around. A brief introduction to Axiom 1 is given below.

Let there be m components represented by a set of independent FRs where FR is the vector of functional requirements. DPs in the physical domain are characterized by vector DP with n components. The design matrix representing the relationship between FRs and DPs vectors is expressed as

                                                                               (1)

                                                                                     (2)

Equation (1) is a design equation for the design of a product, where is a “design matrix” that characterizes the product design. The components in the design matrix are either “0” or “1”. A cell takes a “0” if varying the design parameter has no effect on the corresponding functional requirement and a “1” if it does.

In general, Equation (1) may be written in terms of its elements as,

                                                                                        (3)

where n is the number of DPs.

In the “technology/function” matrix in Table 1~3, the “technologies” resembles the design parameters (DPs), and the “function” resembles the functional requirements (FRs) in Equation (3). For example, in Table 1,

        FR1 = Tighten/ loosen screw

        FR2 = Generate impact torque

        FR3 = Change magnetic flux

The corresponding DPs are as follows:

        DP1 = Motor

        DP2 = Drive shaft

        DP3 = Magnetic hammer

        DP4 = Magnetic anvil

        DP5 = Output shaft

        DP6 = Magnetic bypass device

        DP7 = Changing device

The technology/function matrix in Table 1 can be expressed as

                                  (4)

where  is the transformation matrix which transfers the DPs into FRs. For example, in Equation (5)

                                                   (5)

The first equation above means that “Transforming components motor, drive shaft, magnetic hammer, magnetic anvil, and output shaft achieves function of tightening/ loosening screw.” Similarly, the second equation above means that “Transforming components motor, drive shaft, magnetic hammer, and magnetic anvil achieves the function of generating impact torque”; the third equation above means that “Transforming components magnetic bypass device and changing device achieves the function of changing magnetic flux.”

In summary, a patent can be represented by the following equation:

                                                                                          (6)

or

                                                                     (7)

where [FR] is a column vector of the “functions” of the patent, and [DP] is a column vector of the “technologies (components)” of the patent. Both [FR] and [DP] are extracted directly from the technology/function table of the patent. Matrix A is a design matrix that characterizes the patent. The components in matrix A are 0s and 1s representing the relation between functions and technologies. Finally row vector T is a transformation matrix which transforms the technologies into function.

4.     The design-around algorithm

This section discusses the development of the design-around algorithm. U.S. Patent 6,918,449 is also used to illustrate the detailed steps of implementation of the patent-based design process.

Consider a series of design matrices of existing patents, i = 1, …, n, to be designed around. The purpose of the design-around algorithm developed in this study is to generate a new design matrix  that is similar to one of the existing matrices, but does not infringe on any of the existing design matrices. That is, to generate  such that

         and                                                                              (8)

where “” means “is similar to”, and “” means “does not infringe on”.

Figure 5 shows the flowchart of the design-around algorithm. To start with, the designer must identify the related patents to be designed around and to collect functions (DPs in Equation (7)) and core techniques (FRs in Equation (7)) of each related patent, as in standard patent analysis. Each patent is then symbolized by a “design matrix” converted from the DPs and FRs of the patent.

After transferring the related patents into design matrices, the designer has to assign the priority of DPs to be designed around. The priority of DPs to be designed around is given to those having the least influence in the design matrix, which are the DPs having the least contribution to the FRs, and the DPs having minimal interaction with other DPs. The influences of the DPs are represented by the number of non-zero elements in the design matrix. To assign the priority of DPs to be designed around, the columns and rows of the design matrix are sorted according to the number of non-zero elements.

After the priorities of DPs are decided, the “design around operation matrices” are applied to the DPs which have the highest priority to be designed around. In this research, four design around operation matrices are proposed. They are applied in the order of “elimination” (to eliminate redundant component), “replacement” or “integration” (to make at least one constitutive DP substantially different), and “decomposition” (to replace a multi-functional technological characteristic with a few separate technological characteristics). New design matrices which do not infringe on the existing patents and the corresponding design problems are generated. New design problems can be identified. In the next stage, TRIZ is used to solve the new design problems and transform the new design matrix back into a real engineering design concept.

Figure 5. Flowchart of the design around algorithm

Equation (9) shows the design matrix representation of U.S. Patent 6,918,449. There are 7 DPs in this patent. To assign the priorities, the columns of design matrix A are sorted according to the number of non-zero elements. Then the rows of design matrix A are sorted according to the number of non-zero elements. In Equation (9), the design matrix A remains unchanged after sorting.  only contributes to one function , and and  only contribute to one function .  and  only interact with each other, while  interacts with 4 other DPs (, ,  and ) to achieve function . Therefore  and  have the highest priority to be designed around, and  has the second highest priority to be designed around. , ,  and  are considered lastly.

                                  (9)

After the priorities of DPs are decided, the “design around operation matrix” D is applied on the design matrix to generate a new design matrix :

                                                                                                 (10)

where  is called the “expansion matrix” of A, defined as

                                            (11)

and c is the number of expanded columns. Note that the patent represented by design matrix A is equivalent to that represented by design matrix , that is, A=. For example,

       

        (12)

The expansion matrix will be needed when new DPs are introduced in the design around process. Next, the 4 design around strategies, elimination, replacement, integration, and decomposition, are converted into different design around operation matrices.

(1)   Elimination

If one or more components in a concerned patent are found to be redundant, they can be eliminated directly to generate a solution with simplified components/functions. For example, in U.S. Patent 6,918,449, in order to avoid falling into the scope of all elements rule, eliminating the magnetic bypass device () or the changing device () can be considered first. Equation (4) shows the design matrix representation of U.S. Patent 6,918,449, where

        A=                                                                  (13)

Let

        D1=                                                               (14)

                                                       (15)

Clearly , because  has been eliminated, and the design-around technique is successful according to the all element rule. The new design can be expressed as

                                        (16)

                                                    (17)

As shown in Equation (17), there is a new design problem to be solved (), which can be translated into:

Design Problem 1: “How to design a transformation  to achieve the function  (change magnetic flux) using component  (changing device)?”

The same process can be used for eliminating  by the following design around operation matrix:

        D2=                                                               (18)

The new design problem to be solved () can be translated into:

Design problem 2: “How to design a transformation  to achieve the function  (change magnetic flux) using component  (magnetic bypass device)?”

(2)   Replacement

“Replacement” means that one or more components of the design matrix can be displaced by another component(s). Replacement does not take place haphazardly but reasonably. In U.S. Patent 6,918,449, in order to avoid falling into the scope of doctrine of equivalents, replacing the magnetic bypass device () or the changing device () can be considered first. A new DP will be introduced in the replacement operation. Therefore the expansion matrix of A is used:

                                                                    (19)

To replace DP6 with DP8, let

        D3=                                                         (20)

                                              (21)

The technological characteristics of  must be different from those of , so that , and the designing around is successful according to the doctrine of equivalents. The new design can be expressed as

                          (22)

                                                      (23)

The new design problem to be solved () can be translated into:

Design problem 3: “How to design a transformation  and a new component  to achieve the function (change magnetic flux) using component  (changing device) and , while the technological characteristics of  are different from those of .”

The same process can be used for replacing  by the following design around operation matrix:

        D4=                                                         (24)

The new design problem to be solved () can be translated into:

Design problem 4: “How to design a transformation  and a new component  to achieve the function (change magnetic flux) using component  (magnetic bypass device) and , while the technological characteristics of  are different from those of .”

(3)   Integration

“Integration” combines two or more different components, and the technological characteristics of the resulting design are substantially different from those of original components. For example, in U.S. Patent 6,918,449, in order to avoid patent infringement by the all elements rule, the new product can be obtained through integration of the two technological characteristics of  and . Again a new component will be introduced in the integration operation, therefore the expansion matrix of A is used:

                                                                        (25)

To integrate  and  into , let

        D5                                                      (26)

                                              (27)

Clearly , because  and  have been integrated into , and the design-around technique is successful according to the all element rule. The new design can be expressed as

                          (28)

                                                      (29)

The new design problem to be solved () can be translated into:

Design problem 5: “How to design a transformation  to achieve the function  (change magnetic flux) using a new component , while the technological characteristics of  are different from those of  and .

(4)   Decomposition

In “decomposition”, one major component is decomposed into several subordinate components, while the technological characteristics of the new components are different from those of the original components. Two or more new components are introduced and the expansion matrix of A is used:

                                                           (30)

To decomposed  into  and , let

        D6                                                   (31)

                                         (32)

The technological characteristics of  and  must be different from those of , so that , and the designing around is successful according to the all element rule. The new design can be expressed as

                     (33)

                                                     (34)

The new design problem to be solved () can be translated into:

Design problem 6: “How to design a transformation  and two new components  and  to achieve the function (change magnetic flux) using two new components  and , while the technological characteristics of  and  are different from those of .”

The same process can be used for decomposing  into  and  by the following design around operation matrix:

        D7                                                   (35)

The new design problem to be solved () can be translated into:

Design problem 7: “How to design a transformation  and two new components  and  to achieve the function (change magnetic flux) using two new components  and , while the technological characteristics of  and  are different from those of .”

5.     Generate real engineering design concepts using TRIZ

After applying the 4 design around operation matrices to the components with the highest priority to be designed around, 7 new design matrices, and therefore 7 new design problems are generated. In this section, the Contradiction Matrix and the inventive principles of TRIZ are used to solve these new design problems.

The Contradiction Matrix in the TRIZ theory contains 39 design parameters and 40 inventive principles for solving related engineering design problems. As shown in Table 4, the designer searches in 39 design parameters to find the ones matching with the functions in the design problem, and the “inventive principles” appearing in the corresponding bracket are the possible guidelines to generate the “transformation” in the design problems described above.

For example, for Design Problem 5 described in the previous section, Parameter 10 (force) is selected as the feature for achieving the function of “changing magnet flux” by . In addition, it is expected that  will be able to change magnetic flux. Therefore Parameter 33 (ease of operation) is selected as the feature to not be deteriorated in Table 4. Four inventive principles can be obtained. They are Principle 1 (segmentation), Principle 28 (Mechanical interaction substitution), Principle 3 (local quality), and Principle 25 (self-service).

Table 4. The contradiction matrix

Undesired result

 

 

Feature to change

1

33

39

Weight of moving object

Ease of operation

Productivity

1

Weight of moving object

 

 

 

 

 

 

 

 

 

 

10

Force

 

 

1, 28, 3, 25

 

 

 

 

 

 

 

39

Productivity

 

 

 

 

 

After reviewing the four principles, Principle 28 was utilized to generate the new concept in the portable magnetic impact tool. In TRIZ, Principle 28 has four explanations:

a.     Replace a mechanical system with an optical, acoustical, thermal or olfactory system.

b.     Use an electric, magnetic or electromagnetic field to interact with an object.

c.     Replace fields that are: stationary with mobile; fixed with changing in time; random with structured.

d.     Use fields in conjunction with ferromagnetic particles.

In particular, “use an electric, magnetic or electromagnetic field to interact with an object” was used to solve Design Problem 5. In the new design concept generated, the new componentconsists of four solenoids. The four solenoids are mounted on the magnetic anvil, and the impact torque can be changed by varying the distribution ratio of the magnetic flux by operating a switch for setting the output of the electric current value. In this concept, the new component has already integrated the function of the changing device and the magnetic bypass device.

The designer can try to find solutions for other design problems utilizing the Contradiction Matrix in TRIZ. However, a good engineering design concept cannot be generated “automatically”. It still depends on the domain knowledge and experience of the designer. Moreover, transformation from a design matrix to an engineering design concept may fail because there may not be a feasible design corresponding to the new design matrix generated by the algorithm. For example, Design Problem 2 described in the previous section is not feasible because the component  only performs the function “move magnetic bypass device,” it is unable to change magnetic flux by itself.

6.     The computerized design-around tool

The patent-based design process is integrated into a computerized “Design-Around Tool (DAT)”. After defining the technology/function matrix of the patent to be designed-around in DAT, the designer can conveniently obtain a series of design problems to be solved, sorted by the extent of variation to the existing patent. In this section, another example, a design around problem of a golf club head with weight adjustment, is used to illustrate the operation of DAT.

The performance of a golfer is greatly affected by the selection of golf clubs. The “swing weight”, the weight distribution and the center of gravity of the golf club head, is one of the major concerns when selecting golf clubs because the swing weight significantly affects the driving characteristics.

Weight adjustment mechanism is often incorporated into the design of the golf club head, so that the golfers can customize the swing weight in different situations. Many related patents on weight adjustment of a golf club head can be found in a standard patent analysis. Figure 6 shows a golf putter head with weight adjustable arrangement which is disclosed in U.S. Patent 6,348,014[2002]. According to the claims of this patent, there are 5 components, receiving holes, weight adjustable arrangement, annular locating groove, rubber retaining ring, and golf putter head. The weight adjustable arrangement made by aluminum alloy or magnesium alloy is fasten to the receiving holes. The golfer can use different weight adjustable arrangements to change the center of gravity of the golf putter heads. After a patent analysis, this patent was identified by a golf club manufacturer as the patent to be designed around. Table 5 is the technology/function matrix of U.S. Patent 6,348,014.

Figure 6. U.S. Patent 6,348,014

Table 5. Technology/function matrix of U.S. Patent 6,348,014

           Functions

Technologies

Comprise the body

Fix the weight adjustable arrangement

Change the center of gravity

receiving holes

 

weight adjustable arrangement

 

annular locating groove

 

 

rubber retaining ring

 

 

golf putter head

 

As shown in Figure 7, designer imports the technology/function matrix into DAT (upper window in Figure 7). DAT then starts the design-around algorithm and outputs a series of design problems to be solved, sorted by the extent of variation to the existing patent (lower window in Figure 7).

Figure 7. User interface of DAT

After reviewing the list of design problems, one problem was identified by the golf club manufacturer as the design problem to be solved:

“How to design a transformation  to achieve the function  (fix the weight adjustable arrangement) using a new component , while the technological characteristics of  are different from those of ,  and .

This problem was then solved using the Contradiction Matrix in TRIZ. In the Contradiction Matrix, parameter 13 (stability of object) was selected as the feature for achieving the function of “fixing the weight adjustable arrangement” by . In addition, it was expected that  would be able to fix the weight adjustable arrangement. Therefore Parameter 33 (convenient of use) was selected as the feature to not being deteriorated in Table 4, in which the three inventive principles can be obtained. They are Principle 32 (optical changes), Principle 35 (physical or chemical properties), and Principle 30 (flexible films or membranes).

After reviewing the three principles, Principle 30 was utilized to generate the new concept in the golf club head with weight adjustment. In TRIZ, Principle 30 has two explanations:

a.     To use flexible shells and thin films instead of three dimensional structures;

b.     To isolate the object from the external environment by using flexible shells and thin films.

In particular, “Use flexible shells and thin films instead of three dimensional structures” was used to generate new design concepts to the design problem presented above. In the new design concept generated, the new component  consists of spiral power spring. As shown in Figure 8, a tank in the golf club head contains the weight adjustment device comprised of an axle and the spiral power spring. The center of gravity of the golf club head can be changed by using a tool to rotate the axle. The spiral power spring inside becomes smaller and can be fit into the tank or taken off the tank. Finally the golf club manufacturer then developed the innovative design concept in Figure 8 into a prototype as shown in Figure 9.

Figure 8. New design concept of new component

Figure 9. The prototype of golf club head

7.     Conclusions

The design problem constantly faced by engineering designers across industries is how to design around existing patents, instead of generating a completely innovative design. Although patent analysis has almost been a standard process in the early stage of product development in industry, information obtained from patent analysis is often not fully utilized.

This paper proposes a patent-based design process by systematically integrating patent information, the rules of patent infringement judgment, strategies of designing around patents, and innovation design methodologies. The basic idea is to consider patent infringement before engineering design concepts are actually generated. Design matrices are used as the mathematical representations of patents and design around operations, such that a new design matrix that does not infringe on design matrices of existing patents can be generated by mathematical manipulations. New design problems are formed. Finally the Contradiction Matrix in TRIZ, which is a perfect match to this design process, is then used to generate a real engineering solution.

The whole process is integrated into a computerized “Design-Around Tool (DAT)”. By defining the technology/function matrix of the patent to be designed-around in DAT, the designer can conveniently obtain a series of design problems to be solved, sorted by the extent of variation to the existing patent.

This design process aims to assist enterprises to enhance the efficiency of product development, lower the possibility of patent infringements, and increase the potential to patent results of innovation. From another point of view, the enterprises can also use this process to check whether it is easy to design around their own patents, and how to establish a complete patent portfolio without any possible loopholes.

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