Image Image Image Image Image Image Image Image Image Image
Scroll to top

Top

Assessing The Accuracy Of The Contradiction Matrix For Recent Mechanical Inventions

| On 18, Feb 2002

Assessing The Accuracy Of The Contradiction Matrix For Recent Mechanical Inventions

Darrell Mann
Industrial Fellow, University of Bath
Bath, BA2 7AY, UK
Phone: +44 (1225) 826465
Fax: +44 (1225) 826928
E-mail: D.L.Mann@bath.ac.uk

Introduction

While some parts of the TRIZ community might debate the value of the Contradiction Matrix (Reference 1, 2) as a problem-solving tool, it is undoubtedly an attractive concept to both users and newcomers. A large part of the dis-satisfaction with the Matrix seems actually to stem from the fact that it is out of date rather than conceptually incorrect, and that to update it would require a lot of effort that might be better spent elsewhere.

A previous article (Reference 3) included the following figure as a way of highlighting the extent of the problems associated with the current classic Matrix. Or rather, due to its lack of quantified data, suggested the extent of the problems.

Figure 1: Relative Efficacy of Contradiction Matrix For Different Problem Types

This article reports a brief study conducted by 32 final year engineering and design undergraduates at the University of Bath to calibrate the Matrix against a cluster of recent mechanically-oriented inventions.

Method

The study was conducted by allowing students to select a random set of patents from the US and European patent databases, the only criteria being that the patents should describe an essentially mechanical-based system and that the patent should have been granted in the last ten and preferably five years. No other selection criteria were formally applied, although there was an overall suggested direction towards picking inventions that were ‘interesting’ in some form or other – this usually meant a solution featuring some kind of ‘wow’ moment. Each student was tasked with identifying four patents for analysis – and hence the total dataset for analysis comprised over 130 different inventions.

For each patent, the student was required to identify what aspects of a design the inventor was seeking to improve, what parameters these aspects conflicted with, and how the inventor overcame the conflict. In broad terms, these elements can be extracted from the background, summary and claims sections of the invention disclosure text. For each patent, the student was required to cut and paste the relevant section of text, show how it mapped onto the terms of the Matrix, and show if/how the inventive step related to one or more of the Inventive Principles. There was no instruction to distill either conflict parameters or Inventive Principles down to a ‘best one’; if the inventor solved more than one conflict, or if the conflict was blurred across several parameters, or if more than one Principle was used, the student was asked to record all of the information.

Below is an example of the type of analysis conducted for each patent:

Figure 2: Exemplar Patent – US6,230,788

From the patent text…..

BACKGROUND OF THE INVENTION
The invention relates to a device for applying labels, as defined in the preamble of the independent claim 1.

Applying labels to flat mail items quickly and reliably poses a problem in the processing of flat mail items,

particularly letters, post cards, etc., in mail-processing facilities. An example of this is automatic mail forwarding.
In this instance, mail items are separated out for forwarding addressing, and re-addressed with corresponding,
predetermined data stored in a database. A label that covers the old address and, if applicable, a barcode
printed on the surface of the mail item, is affixed to these items. The label is then provided with a new barcode
and the corresponding, new address. The label is applied in devices that are integrated into automatic letter-
distribution systems. The mail volume for such distribution systems varies in format, weight and thickness. In
these systems, the items are conveyed at a speed of, for example, 3.6 m/sec, which places stringent
requirements on the speed at which the labels must be applied, as well as on the exact positioning of the
labels. Furthermore, the handling and especially the transport of the labels to the item surface represent a
general problem when the label has a self-adhesive surface.

A device of the above-outlined type is disclosed in U.S. Pat. No. 5,200,007.

It is the object of the present invention to provide a device for applying labels to flat mail items, wherein the

supply of the labels to the region of application and the trimming of the labels is performed inexpensively with
high advancing speed and accurate positioning.

According to the invention, this object is accomplished by the features of claim 1. Advantageous embodiments

of the invention ensue from the dependent claims and the description.

A notable advantage of the invention is a high flexibility in the positioning of the labels on the mail items, and

a simple process of supplying the labels to the application region. The conveying speed of the mail items
need not be reduced for label application. For the duration of the process of supplying the labels to the
application region, and during the application itself, the labels are mechanically held, so no uncontrolled

changes in position occur. The labels can be supplied from a simple label strip or a label carrier strip.
etc

….the student is required to pick out the conflicting parameters….

….see what the classic Matrix recommends as its ‘top 4 most likely’….

Matrix recommends:-

Parameter Changes, Prior Action, Curvature

….and then pick out the Inventive Principles actually used by the inventor….

Siemens used:-

“…a label conveying and cutting device that is controlled by a sensor device for determining
the position of a front edge of the flat mail item…”

Prior Action, Feedback

….and so, in this case, we are able to record a partial match between Matrix and what the inventor used. Thus, in terms of quantifying the ‘success’ of the classical Matrix, this invention scores one out of two – i.e. two Principles were used; the Matrix suggested one of them.

The total success rate of the Matrix was then calculated by summing all the Principles contained in the Matrix used by each inventor, and dividing that total by the sum of every Principle used in each of the patents under evaluation.

Throughout the exercise – carried out over a period of two weeks – students were also asked to pay attention to either conflict parameters or inventive strategies that did not fit into the existing Matrix/Inventive Principle framework.

Results

The following table summarises the analyses for each of the patents successfully analysed. In order to ensure consistency of analysis across each patent, this author has monitored each one individually. The table provides patent number, title, improving parameter(s), worsening parameter(s), Inventive Principles recommended by the classic Matrix, and Inventive Principles used by the inventor. Anyone wishing to see the specific analysis for any of the patents in question may request a copy from the author. Alternatively, you may like to conduct a few analyses for yourself to see if you agree with the diagnoses presented here.

Patent Number Short Title Improving Parameter Worsening Parameter Matrix Recommendation Inventor Used..
4923041 Liquid Friction Coupling Blade 10 13 3 35,10,21 17,19,9,36 35, 17, 4
4966257 Shock Absorbing Damper 10 5 19,10,15 15
5473723 Optical Fibre Sheath 33 24 4,10,27,22 3
5485307 Binoculars 35 12 15,37,1,8 1
5485359 Remote control Holder 18 19 32,1,19 25
5485360 Miniature Flashlight 11 13 31 35,33,2,40 2,33,27,18 24,23
5493544 Noble Metal Watch Case 26 2 14 14,35,34,10 28,2,27,10 2,35
5493551 Disk Loading Apparatus 33 36 32,26,12,17 17
5493578 Ash Melting Furnace 26 22 7,18,25 25
5493580 Recycling Filter Dust 23 22 35,27,2,31 1,35,31
5540495 Injection Assembly 8 36 10 1,31 2,18,37 31,17
5543179 Head Treatment Device 30 14 35,18,37,1 16,10, 1
5543179 Evaluating Pummelled Glass 37 18 2,24,26 32,23
5544090 Removal of Entities from Textiles 30 15 26 22,15,33,28 35,33,29,31 29,23, 1
5568961 Tubular Seat Frame 14 1 1,8,15,40 1,15
5569009 Loosening Prevention Screw 27 36 13,35,1 1
5569282 Retractable Surgical Knife 31 33 7
5570342 Disk Cartridge 5 36 14,1,13 1
5650591 Waterproof Casing 31 17 22,35,2,24 31
5650983 PCB Magnetic Head 8 2 24 – 10,15,35 5
5650990 Mini-Disc Tray 10 19 13 35,10,21 19,13,17,24 15
5651055 Digital Secretary 33 38 24 4,10,27,22 35,33 10,28
5666803 Vectored Thrust Compressor 31 12 36 32 19, 1, 31 1,32,17,28 1,17
5666937 Repeat-Fire Pellet Rifle 27 36 7 1,13,35 3,10,14,24 10,13
5667294 Strip Sport Light 33 35 15,34,1,16 15,1
5668542 Aircraft Cockpit Display 31 33 36 1,19,31 12,17,26,32 1,32
5680467 Hearing Aid 28 13 32,35,13 35
5680468 Automotive Speaker Equalisation 16 33 1 1
5694827 Cushioned Unloading Cycle for Truck 15 9 3,35,5 3,35,5
5724415 Coin Deflector for Telephone 7 5 1,7,4,17 17
5724478 Liquid Heater Assembly 22 6 17,7,30,18 1,17
5724625 Belt_Driven Shutters 9 11 6,18,38,40 6,1
5724663 Carphone Connected to Audio Unit 31 33 35 – 15,34,1,16 5
5746360 Coat Hanger Bag 7 31 17,2,40,1 2,30
5772623 Easy Removal Bandage 33 31 15 – 29,3,8,25 3,17,5
5790028 Anti-Robbery Handbag 27 24 36 21 13,35,1 10,19 10,24
5810078 Control of Vehicle Interiors 17 28 3,10,19,35 10
5815984 Casement Window Operator 33 13 10 32,35,30 28,13,35 13,24,4
5824184 Peel-off Backing for Adhesive Tape 33 3 1,17,13,12 3
5899166 Boat Hull Protector 33 7 1,16,35,15 35,30
5900705 Bicycle Motor Control 33 31 13,5
5900819 Drowsy Driver Detector 30 33 3 2,25,28,39 17,1,39,4 1,5,35
5900821 Rain Sensor System 32 35 2,13,15 2
5924704 Foot Supporting Roller 15 36 27 10,4,29,15 11,2,13 15
5992588 Suitcase 10 3 17,19,9,36 17
5999869 Electric Power Steering 31 15 15,22,33,31 23
6003407 Motorcycle Toe-Shift Seal 27 36 13,35,1 7,24
6050219 Animal Milking Apparatus 15 25 20,10,28,18 20,23
6053646 Ergonomic Computer Input Device 31 10 9 35,28,3,21 1,28,3,25 28
6053805 Dust Free Sander 26 36 13,35,1 13,3,5
6065555 Power Assisted Wheelbarrow 19 22 12,22,15,24 23
6084576 User Friendly Keyboard 33 5 1,17,13,16 1,13
6098208 Protective Baseball Pads 5 1 2,17,29,4 14,30
6099018 Snowboard Binding 31 12 35,1 1,17
6099150 Bicycle Brake Light 33 15 29,3,8,25 40
6099658 Pool Cleaner 9 31 2,24,35,21 24
6157887 Brake System 36 32 27,26,1,13 26,1,28
6166359 Induction Heating for Pipe Welds 17 22 21,17,35,38 1,28
6176374 Sensitive Component Container 11 14 9,18,3,40 9,3
6179727 Dual Radius Putter 35 36 15,29,37,28 4,20
6182299 Baseball Chest Protector 14 33 17 2,28,32,40 30,10,40 2,3, 40
6203313 Reconfigurable Candle 35 14 35,3,32,6 1,35
6204482 Cooling a Toaster Oven 17 22 31 22,35,2,24 21,17,35,38 1,30
6220333 Bar Code Stencil 24 27 10,28,23 17,28,13
6213258 Auto-Compensating Drum Brake 4 16 8 35,8,2,14 35,34,38 1,15,35
6216864 Golf Club Holder 31 36 19,1,31 31,1,35
6223658 Weighted Paintball 31 35 1,30
6227989 Line Marking System 16 33 31 1,17,40,33 2,25,28,39 17,10, 24,31
6239337 Shoulder Rest for Musical Instrument 35 31 35
6256886 Device for Cutting Vegetation 31 1 36 19,1,31 26,30,36,34 15,28
6257009 Ice Dispenser 39 17 23 35,21,28,10 28,10,35,23 35,23
6260276 Adjustable Length Clipper 35 36 15,29,37,28 15,6
6272687 Needle-Proof Gloves 14 33 32,40,25,2 3,40,15
6279720 Coin Handling Mechanism 27 30 2,27,35,40 2
6283549 Adjustable Office Chair 35 13 35,30,14 14,4
6290148 Fuel Injection Nozzle Delay 38 36 15,24,10 24,10
6290196 Holding Device for Surgical Instrument 3 7 7,17,4,35 3,7, 17
6293565 Roller Hockey Skate 9 35 31 2,21,24,35 – 17,14,3
6296160 Clothes Hanger 31 33 36 19,1,31 32,26,12,17 8,5
6298993 Diaper Bag 33 12 35 7 15,34,1,16 14,4,15,22 1,2
6299550 Golf Ball 3 9 13,4,8 13
6303074 Rotor for Molten Metal Pumping 7 5 19 1,7,4,17 35 17
6305305 Kneeboard 3 10 17,10,4 17
6306040 Telescopic Baton 7 36 26,1 1,15
H1947 Expandable Police Baton 33 14 3 1,17,13,12 1,15,8,35 1,7,17
GB2303376 Pigment Ink 13 26 15,32,35 35,24
GB2303439 Gas Turbine Combustor 13 35 35,30,34,2 35
GB2303469 Vehicle Speed Limiter 24 31 36 – 19,1,31 19
GB2303510 Radar Wheel Detector 30 27 21 27,34,2,40 19,22,31,2 19,28
GB2307485 Bubble Generator 15 10 2,16,19 4,18
GB2309876 Ultraviolet Water Treatment 36 30 22,19,29,40 2
GB2312704 Lifting Offshore Platforms 1 30 22,21,27,39 22
GB2315973 Plant Watering System 23 17 21,36,39,31 31
GB2315980 Sports Shoe 12 8 7,2,35 2,35
GB2315994 Rainwater Collection for Automobiles 26 7 15,20,29 25
GB2316044 Vehicle Wheel Trim 10 33 1,28,3,25 1,15
GB2350145 Escape Ladder Assembly 33 35 15,34,1,16 15
GB2350268 Packet Data Transmission 24 27 10,28,23 10
WO 01/13760 Hyperaemia Comb 7 5 1,7,4,17 17,4
WO 01/70445 Airbag Deployment Trim Piece 28 3 5,16,26,28 5,26

Of the patents analysed, the net effectiveness of the Matrix was calculated as 48%. In other words, in 48% of inventive problem situations, the Matrix in its current form would have enabled the inventor to reach the eventually patented solution.

Conclusions

The classical TRIZ Contradiction Matrix was assembled from primarily mechanically biased patents from twenty or more years ago. While the sample here is of a significantly smaller size than the original analysis, it is nevertheless sufficient to allow some statistical comparison to be made. The 48% success rate, although lower than some estimates (higher than others, however) should give us at least some confidence that the Matrix is still relevant for mechanical problems. The most significant shifts in thinking appear to come through increased use of Principle 23, Feedback, and to a lesser extent 25, Self-Service – and these now appear to be somewhat under-represented in the classic Matrix. Conversely, while the Matrix suggests Principle 22, Blessing In Disguise relatively frequently, the patents analysed suggest it has rarely been utilized. In terms of the 39 parameters contained in the Matrix, it was evident throughout the monitoring of the patents that parameter 31’Object Generated Harmful Effects’ was used in a relatively high number of cases. The parameter has to be used to wrap up a wide variety of issues (safety, noise, environmental harm, etc), which would ideally be handled by introducing more parameters into the Matrix.

The classical Matrix, of course, should not be interpreted as saying that the Principles used or usable to solve a given contradiction type are limited to the ones published – merely that these are the ‘most likely’. If the Matrix recommends any three or four Principles for a given contradiction, it does not preclude the achievement of a strong solution from one of the other 36 or 37 Principles. The results of this study are suggesting that, for mechanically oriented problems, the Matrix recommendations will be ‘right’ just under half of the time. We should continue, therefore, to use the Matrix as a ‘useful start point’ rather than as a definitive end.

Final Thoughts

If TRIZ is about finding win-win solutions and maximizing the utilization of resources, the idea of using students to help update the TRIZ methodology appears to offer a very good match. The activity conducted by this batch of students served to familiarize them with searching patents, observing the way patents are written, understanding contradictions, familiarizing themselves with the Inventive Principles, in addition to providing the TRIZ community with some hopefully useful data.

It would be good to extend this type of analysis to patents from non-mechanical areas in the future. The author is happy to pass on teaching and assignment instruction data for anyone wishing to attempt a similar exercise with students elsewhere.

Meanwhile, CREAX nv in Belgium is in the process of systematically analyzing and codifying patents for contradictions, trends of evolution, inventive standards and knowledge/effects content, starting from the present day and working back in numerical order, patent-by-patent back to the time when systematic analysis previously stopped. The fruits of this updating activity will gradually be published via www.creax.com. Anyone wishing to find out more about this work, or wishing to participate in some way should get in touch with the author.

Acknowledgements

The author would like to thank all of the students for participating in the exercise; without their efforts, this article literally would not have been possible.

References

  1. Domb, E., ‘Contradiction Matrix’, TRIZ Journal, September 1998.
  2. Salamatov, Y., ‘TRIZ: The Right Solution At The Right Time’, Insytec BV, Netherlands, 1999.
  3. Mann, D.L., ‘The Space Between Generic and Specific Solution’, TRIZ Journal, August 2001.

ã2002, D.L.Mann, all rights reserved.