DESIGN DEVELOPMENT OF AN INDIGENOUS TRICYCLE RICKSHAW
Phase 6: Planning for consumption Step 1: Design for maintenance
4.2 Planning for consumption
4.2.4 Design for convenience in use (taking into account Human Factors)
Ergonomics criteria are concerned with ways of designing machines, operations, and work environment so that they match the capabilities and limitations of human operators.
Thus equal emphasis is given to human component in man-machine system.
The application of principles underlying this concept results in :
• Fitting the task to man
• Increasing safety and decreasing chances of accidents and adverse impact
• Increasing efficiency of man - machine operation
• Increasing productivity
• Increasing human comfort
• Optimising effort required to operate the machines.
In the present case there are two components in this system, the puller and the passenger. Objectives set for the tricycle rickshaw to achieve were as under:
Design and Human Factors considerations
i. Features of the new tricycle rickshaw should go along with relevant ergonomics criteria and strive for meeting various context specific requirements. Easy access is to be provided so that both the puller and the passengers can get in and out of the tricycle easily. During movement, sitting should be comfortable.
ii. It should provide protection to both the puller and the passengers from the elements of nature in an inclement weather without increasing the weight of the tricycle excessively in comparison to existing ones which will affect the manual maneuverability.
iii. To the extent possible, the effort required to operate the new tricycle rickshaw should be less and comparable with other benefits available in the existing ones.
iv. Keeping up to the present day transportation needs the new tricycle rickshaw should be able to take quick turns and acquire lesser space on road.
v. It should provide proper space for the user to carry luggage.
vi. It should provide a good feeling to the user, which enhances his desire to use a tricycle rickshaw.
The above set objectives were met and the following are the features of Design for Convenience in use aspects of the tricycle rickshaw (with respect to Ergonomics for rickshaw puller and passengers).
• The tricycle rickshaw has easy access to facilitate the user to get in and out of the tricycle rickshaw. For the puller this has been achieved by removing the top bar of the regular diamond frame made possible due to adaptation of space structure in the interim version of Dipbahan. In the modified Dipbahan+ version, the main frame along with chassis itself was redesigned and fabricated using 25 mm x 50 mm tubular section. For the passengers, the floor level was lowered to the chassis level and this coupled with support to hold for getting in and out of the tricycle rickshaw provided ease of access.
• The passengers should be made to feel comfortable. The angle between the seat and the backrest is maintained at around 100 degrees, which ergonomically is optimum angle for general purpose. The hand rest is given sufficient height of 19 cm from seat surface. The seats are at such a height so that passenger’s legs can easily rest on the surface of the platform. It provides ample legroom for the passengers
• Proper space for carrying the luggage is provided. Reinforced platform for enabling it to support the structure and carrying of luggage is used; it optimizes the available space. Due to the flat horizontal floor and space structure with seat supported on side frames, ample space was available for carrying luggage. The space below the passenger seat is also enclosed from back by the rear panel and at the sides by side panels. These enclosures not only make luggage safe for transportation, but also protect it from soiling in rainy days from mud and muck that gets thrown by the wheels.
• Human dimension for Ergonomic seating arrangement (Chakrabarti, 1997) guided the structure.
• The overall structure protects the puller as well as passengers from the elements of nature (sunshine, rain etc.) though the weight of the tricycle remains similar to the existing ones.
• It is lighter than the traditional rickshaw by approximately 20% (Table 5.4, p 155)
• The shape of the design conforms to aerodynamic orientations with a space frame structure enveloping the puller and the passengers which smoothens manual maneuverability and also protects the occupants from direct impact by other vehicles due to accident as a result of crashes during operation on road to the maximum extent possible.
• The enclosure also acts as a rolling cage and protects the occupants in case of over turn.
• It has an aesthetically appealing form which is visually perceived light with contemporary visual identity giving it a feeling of sophistication, sporty and dynamic, and a overall new look among the existing models of tricycle rickshaws.
• A set of effective mudguards for use in rainy weather.
• Keeping up to the present day transportation needs, the tricycle is able to take quick turns and is stable with low centre of gravity due to lower passengers’ seat position.
• It has been provided with a set of rear wheel brake so that it can be safely stopped by applying brake through the foot pedal. Normally, traditional rickshaws have front wheel braking only and this does not provide smoothness while slowing down the speed and sudden application of brake results in overturn during higher speed and frequent breakage of front axle.
• To facilitate insertion of advertisement for revenue generation to subsidise the cost of the rickshaw to make it affordable, the rear end has a almost flat panel.
• For the rickshaw puller clear vision is one of the most necessary requirement.
The cone angle of 75 degrees in the vertical direction and 30 degrees in the horizontal direction is incorporated.
• To facilitate ease of getting on and off the rickshaw by the puller to his seat, some of the tie rods used in common tricycle rickshaws are removed and the chassis
frame is made in such a manner that the driver embark and disembark easily.
The handle is also modified to incorporate easy riding.