Students’ Project: Aesthetic and Ergonomic Redesign of the Pneumatic

Hammer

JASMIN KALJUN & BOJAN DOLŠAK Laboratory for Intelligent CAD Systems, Faculty of Mechanical Engineering

University of Maribor Smetanova 17, SI-2000 Maribor

SLOVENIA jasmin.kaljun@uni-mb.si http://licads.fs.uni-mb.si

Abstract: - Every successful company aims to design successful products. The first phase of the design process, called product design, is therefore very important. Designers’ obligation is, for better break trough of the product on the market, to apply these demands and expectations to the developing product considering general, objective factors that have influence on design of specific product. Mechanical engineering design education system includes many subjects, which give to the students a lot of basic knowledge. Usually, the students study each of the subjects separately, and have thus difficulties to build the complex knowledge scheme by themselves. Besides, the traditional way of the study is theoretical and individual. Consequently, using their knowledge the students do not know how to deal with real-life problems, especially when they start to work in practice. In this respect the aim of our work is not only to present the complexity of design, but also to simulate the product real-life development process and to prepare the students for their future work in practice through the project-based teamwork. Presented project has been carried out by a group of mechanical engineering students during project oriented practical lessons. All steps, which are characteristic for (computer aided) product design, are shown on an example of pneumatic hammer.

Key-Words: - product design, aesthetics, ergonomics, hand tool, pneumatic hammer, students’ project

1 Introduction Design of the product is very important for its success on the market. Designer takes an active part at development of the product from very early concept phase, which gives him good overview on demands and expectations of the market. Designers’ obligation is, for better break trough of the product on the market, to apply these demands and expectations to the developing product considering general, objective factors that have influence on design of specific product. When designing some products product design has not been very important. In some cases product design has not been part of design process, products’ shape has been determined by its construction. Such cases are mostly products (machines, apparatuses) that are not used in general, or are used for specific purposes (special tools, machines…). However, competition is harder even in this field of products. Products are not evaluated only in sense of technical characteristics, bat also in sense of appearance, ergonomics and even more. Manufacturers are starting to devote attention to the products, which are not well designed, on field of product design. It is a fact that product design is a highly complex activity with a significant influence to overall success of the new product on the market. Involving theory and practice of product design into mechanical design education process has therefore a very important role.

These are main reasons why a group of fourth year mechanical engineering students at the University of Maribor took up the challenge to perform a joint project during practical lessons of the subject of Computer Aided Design and Manufacture. Extensive knowledge and skills from fields of mechanical design and also product design, such as: Design Finalisation, Bio Mechanics and Ergonomics, Freehand Drawing and Painting, Visual Communications and Freehand Rendering, have been used in order to assure adequate results. The group made a decision to (re)design a product that has been underdeveloped in sense of product design. Designing such a product is definitely a big challenge for every engineer and product designer. The group chose a pneumatic hammer. 1.1 Guidelines The mechanical design education process at our faculty is based on the ideas of Pahl and Beitz [1] laid dawn in VDI Guideline 2222 [2]. Therefore the project work follows the design process, which is split into four phases: clarification of the task, conceptual design, embodiment design, and detail design. These four phases are like "red-line" through the design process.

Proceedings of the 6th WSEAS International Conference on ENGINEERING EDUCATION

ISSN: 1790-2769 53 ISBN: 978-960-474-100-7

Groups’ first step has been study of projects already carried out in order to prepare guidelines for realisation of their own project [3]. In this particular case, usual content ofhad to be slightly modified, due to the factcase the task was not to develop a new product but to redesign an existing one on one side and limited time to complete the project on the other side. With approval of lecturer, student decided to perform first two design phases (clarification of the task and conceptual design) with emphasis on: aesthetics (shape), ergonomics, manufacturing and realistic presentation of virtual model. After short study of the selected product, team members agreed to redesign rear handle and design protective body casing. 1.2 Presentation of pneumatic hammersPneumatic hammers are tools used for smashing and drilling of hard materials. They are mostly usedof civil engineering and mining industry. Pneumatic hammers belong to group of tools powered with compressed air and subgroup shock tools. In sense of work principle pneumatic hammers can be divided into two groups:

• drilling and • smashing pneumatic hammers.

Pneumatic hammers are, in spite of modern

technologies, very useful for some purposes. There is infinitive amount of air as media, its storing is relatively simple, and it is free of charge. Physical properties of air allows it accumulate relatively big amount of energy, which in very important for pneumatic hammers and their shock power. Shock power is one of more important features of pneumatic hammer, because it is relatively high regarding to the weight of pneumatic hammers [4].

TABLE 1: OVERVIEW ON DETERMINED CHARACTERISTICS OF PNEUMATIC HAMMER

Characteristic Fact

Usage place direction technique

Construction properties

mechanical characteristicmanufacturing characteristic assembly characteristic

Ergonomics user informationcritical areas needed elements

Aesthetics cognitive comfortemotional contentment

Groups’ first step has been study of projects already carried out in order to prepare guidelines for realisation

usual content of four phases had to be slightly modified, due to the facts that in this

the task was not to develop a new product but to redesign an existing one on one side and limited time to

With approval of lecturer, student decided to perform (clarification of the task and

with emphasis on: aesthetics (shape), ergonomics, manufacturing and realistic presentation of

short study of the selected product, team members agreed to redesign rear handle and design

Presentation of pneumatic hammers Pneumatic hammers are tools used for smashing and drilling of hard materials. They are mostly used in field of civil engineering and mining industry. Pneumatic hammers belong to group of tools powered with compressed air and subgroup shock tools. In sense of work principle pneumatic hammers can be divided into

Pneumatic hammers are, in spite of modern

technologies, very useful for some purposes. There is infinitive amount of air as media, its storing is relatively simple, and it is free of charge. Physical properties of air

late relatively big amount of energy, which in very important for pneumatic hammers and their shock power. Shock power is one of more important features of pneumatic hammer, because it is relatively high regarding to the weight of pneumatic

2 Clarification of the task When designing a product, the designer has to consider various different factors [5]. To join these factors on the product successfully, designer has to be acquainted with wanted properties of the product, as well as its users environment where the product will be used. Therefore designer has to carry out certain analyses or seek for help at corresponding institutions. The goal of the project has been redesign of the handle and design of the casing of already existing pneumatic hammer (Figure 1). Existing pneumatic hammers are not equipped with body casings in basic edition, simple rubber tubes can be provided as body casings on customer request.

Fig. 1. Existing pneumatic hammer(Pneumatic Hammer LRK

General characteristic of the new body and handle were determined by studying the usage of hammers in real-world environment Based on this study, students determined significant characteristic of pneumatic hammer (the pneumatic hammer determines its construction properties and on the other hand requests special attention regarding ergonomics. Aesthetics is alsoimportant due to the users’ cognitive comfort and nevertheless the emotional contentment, when workinwith “nice” tool.

TABLE 1: OVERVIEW ON DETERMINED CHARACTERISTICS OF PNEUMATIC HAMMER

Value

constructing places (buildings, roads, bridges…) horizontal one or both handed, 1 operator

mechanical characteristic solidness, stability, low weightmanufacturing

simplicity, casting

assembly characteristic no tools needed user information male, 18-55 years old, average

contact areas, rear handle, front hand supportneeded elements vibration dampers, sound dilencerscognitive comfort colour combination, graphic detailsemotional contentment solidness, reliability, power

Clarification of the task When designing a product, the designer has to consider various different factors [5]. To join these factors on the product successfully, designer has to be acquainted with wanted properties of the product, as well as its users and environment where the product will be used. Therefore designer has to carry out certain analyses or seek for help at corresponding institutions.

The goal of the project has been redesign of the handle and design of the casing of already existing

atic hammer (Figure 1). Existing pneumatic hammers are not equipped with body casings in basic edition, simple rubber tubes can be provided as body casings on customer request.

Existing pneumatic hammer. (Pneumatic Hammer LRK – 7; Oprema Ravne d.d.)

General characteristic of the new body and handle studying the usage of pneumatic environment.

Based on this study, students determined significant characteristic of pneumatic hammer (Table 1). Use of the pneumatic hammer determines its construction properties and on the other hand requests special attention regarding ergonomics. Aesthetics is also very important due to the users’ cognitive comfort and nevertheless the emotional contentment, when workin

g TABLE 1: OVERVIEW ON DETERMINED CHARACTERISTICS OF PNEUMATIC HAMMER

constructing places (buildings, roads, bridges…)

operator solidness, stability, low weight

55 years old, average contact areas, rear handle, front hand support vibration dampers, sound dilencers colour combination, graphic details

Proceedings of the 6th WSEAS International Conference on ENGINEERING EDUCATION

ISSN: 1790-2769 54 ISBN: 978-960-474-100-7

Fig. 2. Concept sketches of the new pneumatic hammer outer body

3 Conceptual design According to the guidelines described earlier, students performed some research, such as study of literature and study of relevant products on the market, to recent trends of product design and directives of the factors such as aesthetics, motivation, ergonomics and manufacturing [6]. Information collected in the survey determined groups further work. Group entered into conceptual phase with clear objective to determine aesthetic, ergonomic and mechanical characteristics of the pneumatic hammer. In purpose of shape study several concept sketches of the pneumatic hammer casing and handle were drawn and used in continuation of design process (Figure

Team members performed evaluation of the sketches highlighting potentially usable solutions and during dialog derived concept sketch of the pneumatic hammers’ casing and handle, described in continuation. 3.1 Aesthetic and motivation Factor whose influences are to be seen at first is aesthetics. Harmony of the shape can be achieved with suitable proportions of dimensions, considering ways of hammer usage, its construction properties and aesthetic principles of the environment (which disimple and clear lines) in which the hammer will be used. Casing of the hammer is therefore designed to assure certain stiffness, ellipsoid in cross section for

Concept sketches of the new pneumatic hammer outer body

According to the guidelines described earlier, students performed some research, such as study of literature and study of relevant products on the market, to determine recent trends of product design and directives of the factors such as aesthetics, motivation, ergonomics and

Information collected in the survey determined groups further work. Group entered into conceptual

bjective to determine aesthetic, ergonomic and mechanical characteristics of the

In purpose of shape study several concept sketches of the pneumatic hammer casing and handle were drawn and used in continuation of design process (Figure 2).

Team members performed evaluation of the sketches highlighting potentially usable solutions and during dialog derived concept sketch of the pneumatic hammers’ casing and handle, described in continuation.

Factor whose influences are to be seen at first is aesthetics. Harmony of the shape can be achieved with suitable proportions of dimensions, considering ways of hammer usage, its construction properties and aesthetic principles of the environment (which dictates clean, simple and clear lines) in which the hammer will be used. Casing of the hammer is therefore designed to assure certain stiffness, ellipsoid in cross section for

better grip, which is even improved with vertical ribbering in direction of shockdirection for shock damping. Horizontal hollow channel, added to the casing, is used for constructive strengthen of the body, which continues to the base of the handle and serves as combining element between handle and body. Along channel enables precise matching of the ellipsoid parts of the hammer. Design equilibration is finished with outlet slots in upper corner of the casing. Handle is, in contradiction with casing, metal massive, which gives certainsafety while working with hammer. Lover part of the handle – base of the handle, is designed to match with casing. The horizontal channel continues on the handle and forms together with casing channel aesthetic integrity. Aesthetic elements mentioned before are shown on Figure 3.

Fig. 3. Aesthetic elements of pneumatic hammer

Concept sketches of the new pneumatic hammer outer body

better grip, which is even improved with vertical ribbering in direction of shock force and in opposite direction for shock damping. Horizontal hollow – channel, added to the casing, is used for constructive strengthen of the body, which continues to the base of the handle and serves as combining element between handle and body. Along the shape connection the channel enables precise matching of the ellipsoid parts of the hammer. Design equilibration is finished with outlet slots in upper corner of the casing.

Handle is, in contradiction with casing, metal – massive, which gives certain feeling of stability and safety while working with hammer. Lover part of the

base of the handle, is designed to match with casing. The horizontal channel continues on the handle and forms together with casing channel aesthetic

tic elements mentioned before are shown on

Aesthetic elements of pneumatic hammer

Proceedings of the 6th WSEAS International Conference on ENGINEERING EDUCATION

ISSN: 1790-2769 55 ISBN: 978-960-474-100-7

Psychological meaning of separate colour has to be considered when selecting colours for pneumatic hammer. Two colours have been selected, yellow and dark blue, which stand, regarding to the theory of colour, on the opposite sides in colour circle and therefore form rewarding contrast (harmony). Yellow has been selected because of its dynamic, youthfulness and vivacity. Dark blue has been selected as the counterweight to the yellow. It expresses peacefulness, strength and precision. Exposed metallic parts should to preserve characteristic metallic shine, which gives these parts neutrality and reliable strength. From motivation point of view, the hammer is designed to satisfy its users. In concept design of the casing, the handlings, which clearly indicate horizontal use of the hammer, are clearly shown.

3.2 Ergonomics When designing specific part ergonomics [considered with most attention. Ergonomic recommendation about usage suitability for large spectre of users should be considered when designing the casing of the hammer. The most important part from ergonomic point of view is the handle. Several instructions and recommendations [8] about positioning the handle on the product, shape of the handle and rotation of the handle (Figure 4) had to be taken into consideration.

Fig. 4. Recommendations for handle design Dimensioning of the handle has been also very important. Dimensioning has been carried out with help of ergonomic recommendations. Therefore length of the

Fig. 5.(area 1: low load – seldom ribs; area 2: handling area

Psychological meaning of separate colour has to be considered when selecting colours for pneumatic hammer. Two colours have been selected, yellow and dark blue, which stand, regarding to the theory of colour, on the opposite sides in colour circle and therefore form rewarding contrast (harmony). Yellow has been selected because of its dynamic, youthfulness and vivacity. Dark

e counterweight to the yellow. It expresses peacefulness, strength and precision. Exposed metallic parts should to preserve characteristic metallic shine, which gives these parts neutrality and

From motivation point of view, the pneumatic hammer is designed to satisfy its users. In concept design of the casing, the handlings, which clearly indicate horizontal use of the hammer, are clearly shown.

When designing specific part ergonomics [7] has to be most attention. Ergonomic recomm-

endation about usage suitability for large spectre of users should be considered when designing the casing of the hammer. The most important part from ergonomic point of view is the handle. Several instructions and

about positioning the handle on the product, shape of the handle and rotation of the handle

igure 4) had to be taken into consideration.

Recommendations for handle design

Dimensioning of the handle has been also very important. Dimensioning has been carried out with help of ergonomic recommendations. Therefore length of the

handle, shape and size of the cross section of the handle and spacing between handle and the base of could be correctly dimensioned. The handle (Figure 3 – slightly bent regarding to the main handle axe. That insures natural position of the hand on the handle pressure load on the hand is smaller. Position of thehandle on the pneumatic hammer assures that the positions of the main hammer axe and hand axe are coincidence.

3.3 Manufacturing Factor exposed at last has been manufacturing. Various ways of modelling plastic and its basic properties had to be considered [9]. Because the casing has no negative edges, it is relative easy to manufacture using suitable tool – mould. The handle is also designed so it can be manufactured with casting. Several cores for inner holes that cannot be drilled after casting have tobefore casting of the handle. After mechanic handling of the surface follows surface finishing (grinding, polishing and painting) consequence of witch is higher aesthetic value of the product. 3.4 Concept of the inner casing constructionOuter shape of the casing usually does not provide sufficient stiffness. Therefore, inner construction of the product has to be designed. In presented case the inner construction of the pneumatic hammer body is also very important. Casing of the hammer has to,unconditional following to the shape of the hammer core, assure: solidness, stability, low weight, simplicity of manufacturing and ability for using silencers. Inside the casing carrying ribs have been created. Position of the ribs, density and shape depended on their placing on the casing. Casing has been divided on 4 areas (5), depending on part of the hammer core that has been surrounded by the particular part.

Fig. 5. Body divided on characteristic areas seldom ribs; area 2: handling area – dense ribs; area 3: outlet slots – reduced seldom ribs; area 4: possible handling

handle, shape and size of the cross section of the handle and spacing between handle and the base of the handle could be correctly dimensioned.

grey area) is at the backside slightly bent regarding to the main handle axe. That insures natural position of the hand on the handle – pressure load on the hand is smaller. Position of the handle on the pneumatic hammer assures that the positions of the main hammer axe and hand axe are

Factor exposed at last has been manufacturing. Various ways of modelling plastic and its basic properties had to

. Because the casing has no negative edges, it is relative easy to manufacture using suitable

The handle is also designed so it can be manufactured with casting. Several cores for inner holes that cannot be drilled after casting have to be prepared before casting of the handle. After mechanic handling of the surface follows surface finishing (grinding, polishing and painting) consequence of witch is higher aesthetic

Concept of the inner casing construction r shape of the casing usually does not provide

sufficient stiffness. Therefore, inner construction of the product has to be designed. In presented case the inner construction of the pneumatic hammer body is also very important. Casing of the hammer has to, besides unconditional following to the shape of the hammer core, assure: solidness, stability, low weight, simplicity of manufacturing and ability for using silencers. Inside the casing carrying ribs have been created. Position of

ape depended on their placing on the casing. Casing has been divided on 4 areas (Figure ), depending on part of the hammer core that has been

surrounded by the particular part.

reduced seldom ribs; area 4: possible handling – dens ribs)

Proceedings of the 6th WSEAS International Conference on ENGINEERING EDUCATION

ISSN: 1790-2769 56 ISBN: 978-960-474-100-7

4 Model rendering After consonance of all team memberconceptual design, students modelled the solution using Rhinoceros, modelling software which is commonly used by product designers. Virtual model has them been used to create computer rendering of the conceptual design solution. Computer rendering is the procedure of creating realistic digital pictures of computer model. These pictures could be used in communication between designer and person who ordered product or as presentation material for potential costumers. To create renderings of the model, Rhinocerosplug-in Flamingo [11], which works on ray tracing method, has been used. Before rendering, material properties for each part of pneumatic hammer model had to be determined and assigned. Rendering procedure has continued with of the rendering scene. It is very important, for rendering, to choose right background. Therefore special surface behind the hammer has been created and used as a background, so the shadow play would be more realistic and interesting. To completely replace ambient light, three additional lights have been fit to the scene.

Fig. 6. Hammer rendering using additional light After creation of the scene, some renderings with different camera positions have been taken. One of these renderings is shown in Figure 6.

5 Conclusion The paper describes a procedure of product (re)design of pneumatic hammer. The procedure is very similar to the procedures, which are being used in reality, only that we have put some more weight on process of product design, deliberately keeping in backgrmodelling of our product. The realisation of project, gives a very good insight into the development process in general. It is very interesting how several small facts describe the properties of some product and how simple changes in the dimensions or design can have an effect on the functionality of the product or its

After consonance of all team member regarding conceptual design, students modelled the solution using Rhinoceros, modelling software which is commonly used by product designers. Virtual model has them been used to create computer rendering of the conceptual

ing is the procedure of creating realistic digital pictures of computer model. These pictures could be used in communication between designer and person who ordered product or as presentation material for potential costumers.

odel, Rhinoceros [10] ], which works on ray tracing

method, has been used. Before rendering, material properties for each part of pneumatic hammer model had

Rendering procedure has continued with preparation of the rendering scene. It is very important, for rendering, to choose right background. Therefore special surface behind the hammer has been created and used as a background, so the shadow play would be more

letely replace ambient light, three additional lights have been fit to the scene.

Hammer rendering using additional light

After creation of the scene, some renderings with different camera positions have been taken. One of these

The paper describes a procedure of product (re)design of pneumatic hammer. The procedure is very similar to the procedures, which are being used in reality, only that we have put some more weight on process of product design, deliberately keeping in background computer

The realisation of presented , gives a very good insight into the development

process in general. It is very interesting how several small facts describe the properties of some product and

n the dimensions or design can have an effect on the functionality of the product or its

manufacturability, which is ultimately a very important factor. When redesigning the pneumatic hammerfaced several problems theytheir studies. Students were able to finish They acquired a lot of new knowledge, which cannot be acquired during conventional study processes. Moreover, as a final stage of their development process made an overall graphic layout of the hammer, which is very important for marketing. It is meant as the first contact with potential customers and is, therefore, worthy of special attention. It is very important to mention, that the computer model of the product created during the procedure can be exported from Rhinoceros into any other CAD software (Catia,…) where the development can continue with some engineering analyses, product optimisation and preparing procedure for manufacture the product

References:

[1] Pahl G., Beitz W.Systematic Approach. Springer Verlag, 1996.

[2] VDI-Richtlinie 2222: Blatt 1technischer Produkte (Design engineering

methodics. Conceptioning of industrial products)

Dusseldorf, VDI – Verlag, 1977.

[3] Novak M., Požun M.Mobile dwelling unit developed by a group of mechanical engineering design studentstechnol. des. educ., 2004, vol. 14, no. 3, 312.

[4] SŽ, Oprema Ravne, d.o.o.pneumatic hammers, Ljubljana,

[5] Gordon M. J. Jr., Industrial Design of Plastics Products, John Wiley & Sons, 2003.

[6] Keller G., Dizajn, Vjestnik

[7] Kroemer K., Kroemer H., KroemerErgonomics – How to design for ease and

efficiency, Second Edition,

[8] Kaljun J., Dolšak B., Knowledge Base for Ergobomic Design Support,on information science and applications

Vol. 9, 2006, pp. 1717

[9] Dobravc M., Computer Aided Product

Development from plastic materials

thesis supervised by Dolšak B. and Ren Z., Faculty of mechanical engineering, Maribor, 2007.

[10] Cheng R. K. C., Inside RhinocerosPress, 2001.

[11] Mc Neal R., Flamingo on

manufacturability, which is ultimately a very important

redesigning the pneumatic hammer students they were unaware of during

were able to finish their project successfully. acquired a lot of new knowledge, which cannot be

acquired during conventional study processes. Moreover, development process students ic layout of the pneumatic

, which is very important for marketing. It is meant as the first contact with potential customers and is, therefore, worthy of special attention.

It is very important to mention, that the computer ated during the procedure can be

exported from Rhinoceros into any other CAD software (Catia,…) where the development can continue with some engineering analyses, product optimisation and preparing procedure for manufacture the product.

G., Beitz W., Engineering Design, a

. Springer Verlag, 1996.

Richtlinie 2222: Blatt 1, Konzipieren

technischer Produkte (Design engineering

methodics. Conceptioning of industrial products), Verlag, 1977.

., Dolšak B., Počivavšek T., Mobile dwelling unit developed by a group of mechanical engineering design students, Int. j.

, 2004, vol. 14, no. 3, pp. 301-

SŽ, Oprema Ravne, d.o.o., Presentation portfolio of Ljubljana, 1998.

Industrial Design of Plastics

, John Wiley & Sons, 2003.

Vjestnik, Zagreb, 1981.

Kroemer K., Kroemer H., Kroemer-Elbert K., How to design for ease and

, Second Edition, Prentice Hall, 2000.

Kaljun J., Dolšak B., Knowledge Base for Ergobomic Design Support, WSEAS transactions on information science and applications, Iss. 3,

-1724.

Computer Aided Product

Development from plastic materials, specialisation thesis supervised by Dolšak B. and Ren Z., Faculty of mechanical engineering, Maribor, 2007.

Inside Rhinoceros, On World

Flamingo on-line help.

Proceedings of the 6th WSEAS International Conference on ENGINEERING EDUCATION

ISSN: 1790-2769 57 ISBN: 978-960-474-100-7