DESIGN DEVELOPMENT OF AN INDIGENOUS TRICYCLE RICKSHAW
Phase 6: Planning for consumption Step 1: Design for maintenance
3.6 Feasibility study
3.6.2 Identification and formulation of the design problem
Second step in feasibility study is the identification and formulation of the design problem. The information required for this step is derived from the results of the preceding step, particularly the specifications of desired output and relevant technical knowledge about environments, resources and the general engineering principle. An activity analysis is performed with this information as the basis to provide a technical formulation to the design problem. Before considering this step to be complete, it was ensured that the resulting engineering statement of the design development of a tricycle rickshaw is sufficiently relevant and adequate to commit the ensuing steps to the design.
More and more new information was constantly developed by the design work itself.
Previously these were either overlooked or unknown. This new information changes the confidence levels on which prior decisions were made.
The following factors were identified and design problem was formulated in the
• Being a 3-wheeler, stability of the proposed design is to be ascertained.
• Fabrication process for the new rickshaw to facilitate use of commonly used modern materials and manufacturing processes such as mass manufacturing through assembly process.
• Possibility of outsourcing parts and components for the rickshaw from the readily available standard parts / components bins from existing bicycle and tricycle industries. This can facilitate in reduction in capital cost of the project for manufacturing in addition to ease of maintenance of the new rickshaw.
• Protection of the puller and the passengers from the elements of adverse weather requires a canopy on the top and need to explore the possibility of providing supports for the canopy in the design as an integrated aspect.
• Provision of proper space for carrying the luggage.
• Ergonomic seating arrangement.
• Ample legroom for the passenger.
• Effective mudguard.
• Protection of the occupants from direct impact from heavier vehicles.
• Possibility of incorporating advertising space to facilitate acknowledging the sponsorship for economic contribution by the sponsors or as a way of earning revenue through provision of advertisement space.
Preliminary Design Concepts:
After detailed study of the existing tricycles used for transporting passengers all over the world, new concepts were generated in the context of the local situation. Before conceptualization, a list of constraints were identified for the sake of practicality.
These are:
• As far as possible cost of the tricycle rickshaw must be within the targeted amount of Rs. 6,500.00 as decided in a meeting with the likely implementing agency, Centre for Rural Development (CRD), Guwahati. This is the retail price.
Therefore one must consider the profit margin also within it.
• To achieve the above constraint, design must outsource maximum parts and components from the available parts bins of existing bicycle and tricycle rickshaw.
This will reduce capital cost of the manufacturing unit and thus will require lower amount as return on capital.
• The stability of the existing tricycle rickshaw in Guwahati specifically, was found acceptable with the existing foot prints of the 3 wheels. The wheel base of rickshaws in Guwahati city was found to be maximum compared to other places in the North Eastern Region of India and it has continued traditionally over the years. May be it is because of the fact that Guwahati is the biggest and oldest city in the North Eastern Region of India and has best road infrastructure in terms of surface quality , width of the roads, straight roads etc. and hence the longer rickshaws are not a hindrance. Compared to this, roads in various towns are
narrow, with sharp turns etc and rickshaw pullers prefer shorter rickshaws. The wheel base of a rickshaw is not governed or prescribed by any law/ government regulations. It is entirely dependant on the local decentralised fabricators of the rickshaw in various locations. Thus it was decided that the existing foot prints of the tricycle will be retained. This means the track and wheel base will be unaltered. Stability of the rickshaw can be still enhanced if Centre of Gravity can be lowered. This is possible if the passengers’ seat can be lowered in the new design. Dipbahan based on longer wheelbase as that prevailing in Guwahati provided ample space to the passengers including luggage space. This was welcomed by the passengers all over the country as found later, but rickshaw pullers in Imphal in Manipur, Silchar in Assam and Agartala in Tripura were not that happy since with good luggage space, passengers were seen to be taking advantage of this feature that made rickshaw pullers toil more. However passengers paid more for this features and except for few rickshaw pullers, this design decision was otherwise welcomed by all.
• Materials used for fabrication was one of the critical parameter in this design.
Existing rickshaw uses multiple materials as evident from the analysis of these rickshaws for materials and processes used. In the new design, emphasis was laid on reducing the types of materials to a few. Thus mild steel (MS) was identified as the predominant one, since most of the other items used in the existing tricycle were available in mild steel/steel and will be easier to join with each other. It is also convenient that MS is widely used nowadays for fabrication of various items ranging from grills, gate and truss of house to various furniture items like storage cupboard, storage racks, display cabinets etc. even in small town and villages. This will ensure easy maintenance of the rickshaw.
Based on the above criteria a few concepts were conceptualized; these are:
Concept 1
Fig. 3.40, p 93. A tricycle with existing foot prints but with extended roof fulcrumed permanently over the passengers and the pullers with identical configuration of existing rickshaw (Delta configuration)
Concept 2
Fig. 3.41, p 93. A tricycle with two wheels at the front and single wheel at the rear with extended roof fulcrumed permanently over the passengers and the pullers. (Tadpole configuration)
Concept 3
Fig. 3.42, p 93. A tricycle with existing foot prints and with extended roof fulcrumed permanently over the passengers and the pullers with identical configuration of existing rickshaw, but replacing the structure completely with MS structure.
Concept 4
Fig. 3.43, p 93. A tricycle rickshaw with existing foot prints with a space structure/monocoque body made in tubular material in MS similar to that of the trike designed earlier with recumbent style pedaling.
Concept 5
Fig. 3.44, p 93. A tricycle rickshaw based on a bicycle with a side car as available in South East Asia but with integral canopy to protect both the passengers and the pullers with a space structure/ monocoque body made in tubular material in MS.
Concept 6
Fig. 3.45, p 93. A tricycle in the form created for the disable person in the first part of this thesis/ research work but puller pedals it like a normal (upright style of pedaling) rickshaw.
For all these concepts, wherever required, a full scale tape drawing was initiated to study the overall form, scale and proportion.
Fig. 3.40 Concept 1-delta configuration rickshaw with extended canopy
Fig. 3.41 Concept 2 –tadpole configuration rickshaw with extended canopy
Fig. 3.42 Concept 3 -delta configuration rickshaw in mild steel structure with extended canopy
Fig. 3.43 Concept 4- rickshaw based on trike designed earlier with recumbent style pedaling
Fig. 3.44 Concept 5 -rickshaw based on a bicycle and a side car in mild steel
Fig. 3.45 Concept 6- rickshaw based on trike designed earlier with upright style