Load Carrying Device (2016) | SRISTI Summer School

LOAD CARRYING DEVICE

May 2016

Problem Statement

Labour community across India is lifting, carrying and moving objects on head since a long time. A load carrier would distribute load from head to shoulders and solves the complex traumatic problems caused by work drudgery. Also, it is a multipurpose device that can be used for a wide range of jobs.

Even though we already have a few designs of load carrier available but still they are not efficient enough to be implemented. Labourers carrying heavy loads like cement, brick, grain bags, vegetable bags, and luggage often bear medical injuries like neck pain, back pain, knee – joint pain, and fractures. Thus the aim is to design a load carrier that can ease the manual labour and exertion on the labourer and increase his/her efficiency.

Field visit

1. CONSTRUCTION SITES (NAVRANGPURA)

As a part of our first field trip, we visited two construction sites to observe and understand the processes used by construction labourers in their daily working activities. We surveyed and talked to the labourers, both men and women, about construction work in general, the technicalities involved in the process, and also tested the prototypes made by participants of last year’s summer school to understand the reasons as to why the prototypes could not be used. We made several interesting observations about their work style as well as the usage of previously made prototypes which could be helpful in order to come with the design of a load carrying device which could be implemented successfully in daily construction processes.

General Observations:

The load carried by construction site workers is mostly cement, sand, stones and bricks

Two workers are required to lift and place the load (both cement and brick loads) on one of the workers who then carries away the load to further distances

Unloading of both cement and bricks however requires only one worker

The weight is generally carried on the head by the workers, and varies from 25-30 Kgs in case of sand/cement and around 40 Kgs (or 12 bricks) in case of bricks

The workers in general had to travel distances less than 500 meters while carrying load, and most of the load lifting task was done by women, while men were engaged in tasks which involved more of machinery

Most of the material to be transferred to floors above ground was carried by trolleys using pulley system, while workers were mostly carrying the material around the floor

The workers did not report any problems with the current construction processes. However as our conversation proceeded further, they mentioned a few problems like physical exertion which they had become used to due to years of construction work, but would be a major problem for newcomers in this field of work

The contractors said that the workers are paid daily on the basis of the amount and precision of work they do, while construction workers said that they are all paid equally on a daily basis irrespective of the amount/quality of work they do

The workers were happy while using the previously developed prototype when they tried to carry the load with it, and said that it actually made the load feel lighter compared to carrying it on head

The workers also expressed their inability to buy any such prototypes, and said that they would be happy to use any such other method to lift the load if the contractors would provide them with such prototypes

The quality factor for the load being carried at the construction sites was not a major issue, and materials such as bricks and sand were handled roughly by the workers, literally thrown while unloading

Problems with Previous Prototypes:

Balancing of the load was a major problem. The load moved on plates as the workers travelled from one point to another, and could have even fallen off in the way

The gripping of the load was poor and required certain walls to be built around the tray so as to prevent the load from falling off the plates

The workers had to sit on the ground to pick up the load unlike the earlier manual method wherein they could lift the load while standing. This caused them to disbalance while lifting up the load from the ground

The CG for the worker-prototype system was not balanced and lied outside of the body of the worker causing him to swing and deflect sideways

The currently existing prototype requires two workers for both loading and unloading

The head carrier was too high and was not appropriate for both loading and unloading

2. GRAIN MARKET (CHOKHA BAZAR)

The second stop for the field trip was the Chokha Bazaar – the grain market. Labourers in the market are often responsible for loading and unloading of grain bags from the truck, and carrying it to the respective stores, which also involved the labourers climbing up and down the stairs. The purpose of the visit was to observe the process labourers use, analyze it, and see if a better procedure for lifting the same load can be devised or not.

A typical grain bag ranges anywhere from 50 – 100kgs. The extrusions seen in the sealed area are used by the labourers to lift the load. Some labourers used one side of the bag to carry the load whilst the others used both extrusions. When labourers carried the bag from just one side their whole body bent forward and in an one direction. This we felt, had a high risk of them falling down since the whole weight of the bag fell on one side of the body and their gait looked unstable too. Others who carried it on both sides both shoulders had a visibly better balance but still bent down.

Still others used a hook shown above to carry these bags. The traditional practice was to hook the bag on from the upper half onto the hook and lean forward like one shoulder bag carriers mentioned earlier. This didn’t completely stop them from bending forward but halved the amount of weight on their back, since the other half was rested on the hook. The cloth wrapped around the hook provided a better grip on the load.

General Observations:

On talking to the labourers there, we figured that the labourers had been using the hook since a long time in the past to facilitate the process of carrying the load.

When asked if they’ve had any problems carrying the load, they hesitated initially. They would say that they have been doing this for a long time to feel pain anymore. They later said that the people who start carrying load do feel pain and that they too suffer back pain, neck pain. Upon a much closer investigation, we figured that the situation was much more serious than it presented itself on the surface.

The labourers incurred serious injuries on their neck area a lot, mainly because the whole weight of the bag always fell on one side of the shoulder. The hook additionally would also cause injuries at times because they carried it very close to their chest area.

They added that the bag had to be carried up to its final location without a stop. This meant that the labourers would at times rush to go to the store if the bag got disbalanced; which implies that there’s some risk of falling down with the bag. We also asked them if they had used some other method rather than the traditional hand method or carrying it with a hook which has been in practice for some time now, to which they said that these methods have been the most effective so far.

Thus the problems identified were:

Heavy weight on one side of the shoulder.
Climbing up the stairs with heavy luggage.
Dis-balance
Bending down which would eventually lead to an improper body posture and lead to back problems.
Medical injuries

Some of the labourers complained that no new device will be able to help them. Their manager said that it is in the fate of labourer to do hard and painful work. He continued to say that a labourer can never live a comfortable life. However, when we showed him the prototype designed for construction site, their opinions changed instantly and he felt more optimistic, and admitted that something better could be designed. The labourers admitted later that this method although in practice, is painful and they would love to try something new.

On concluding thoughts, the aim is to design an equipment that reduces load stress from their back and allows them to carry the load maintaining a straight body posture and without any device like a hook (that poses harm to them).

3. RAILWAY STATION (KALUPUR)

The third stop for field visit was Kalupur Railway Station. Coolies are often required for carrying heavier load in and out of train, involving the Coolies to climb up and down the stairs. The main purpose of the visit was to analyse the methodology of load carrying by the coolies and to devise a better method for the efficient load carrying.

General Observations:

The average amount of load that the coolie used to carry was around 40 kg.

Since the load carried by the coolie had a variety of shape, they insisted that the design for load carrier should be such that it can carry different shape of goods.

Generally they used to carry four bags on head and two bags on shoulder.

They also use trolley in case the load is very much which is issued by the union on the submission of certain fee and upon the request of the passengers. They usually use lift in case they are carrying the load on trolley.

They have health problems too such as joint pain due to carrying load though they are used to carrying of load. Many a times, they fell which lead to serious injury under the pressure of load and the demand of carrying the load in minimum time.

Railway had earlier introduced the trolley system for the passengers for carrying load. But, it ultimately lead to the high traffic at lift for the movability of trolley which ultimately led them to miss their train. Thus, this system was totally scrapped

Coolie also informed us that their market has significantly reduced due to increased use of the trolley bags for load carrying. Most of the times, people prefer to carry their load themselves. The need of coolie is required only in the case if there is too much luggage.

Coolies also told us that the use of the load carrying device will make their work easy, then why would the passengers pay them.

They usually need to cover a distance of around 400-700 meters. They also informed us that they face problem in climbing up and down the stairs.

They also have problem in transporting the load in heavily crowded platform.

We showed them previous year design and tried to get their feedback. They insisted that the design should consist of component involved in carrying load at head only.

They also insisted that the load carrier should be detachable, if it is not portable they would be having problem in getting customers and searching for the load carrier.

Thus, the problems identified were:

Problem in climbing the stairs up and down while carrying the load.
They wanted the load carrier for head only.
Improper distribution of weight of the load.
Problem in transporting the load in crowded area during the peak time.
Injuries due to imbalance of load.

Some of the coolies said that no new device will be able to help them. As they need to find the customers first and finding the customer is itself a competitive task. When they were showed the prototype designed for construction site they admitted that something better can be designed which would be really useful for them. The labourers admitted later that this method although in practice, is painful and they would like to try something new.

4. VEGETABLE MARKET (JAMALPUR)

We tried to identify the potential problems and existing difficulties faced by the labourers at the vegetable market at Kalupur. Some of the key observations that we made at the market are:

General Observations:

They have to load and unload the vegetable trucks throughout day and night and have to carry the vegetable sacks up to 100 – 500 meters depending about the situation and traffic inside the market

They used to carry load ranging from about 40 – 80 kgs and that too consisted of different kinds of vegetables.

Their wages were dependent on amount of work done by them i.e no. of vegetable sacks loaded/ unloaded by a worker at a time.

Different Vegetables are transported in containers (or bags) made from different kinds of materials which may cannot be loaded and unloaded using the same mechanism.

Different vegetables have different properties like some are larger while some are too small in size , and some can roll while some other can’t, so it is not possible to start off by addressing the problem with a common product for all

By focusing on vegetables we need to study that how efficient our product would be? It can easily damage the soft vegetables when they are stacked on one another.

The vegetable waste generated was just deposited in the surroundings and were not dumped or used for any further use.

Mind Mapping

Following are the points according to which we worked on the mind map

Understand the potential problems and needs of the workers at present
The efficiency of present techniques
Easing out their efforts to increase their efficiency
Overall mechanism of the device and design features (working as well as comfort) to be included in the load carrier
People’s willingness move on to new techniques and accept the prototype
Overall user base of the load carrier and which community of people to focus on
Safety measures to be taken
Materials required in making the prototype and materials to be carried
Cost benefit analysis of the prototype

EXISTING TECHNOLOGIES/METHODS

Load carrying device by Vikram Panchal (NID, Ahmedabad)

The design has two major parts, one that holds the load and the other that rests on the shoulder. Device has two knobs, which facilitates the change of required function manually from one to another in one minute duration. This allows three modular functions for carrying lighter loads on the head, medium loads at the back and heavier loads to push or pull as trolley. Ergonomically the load is distributed on the shoulder and at the lumber support by softer material. The total weight of device is 2 kg and would cost approx. Rs 300 in mass production.

WHAT TO AVOID:

The aim of the load carrying device is to ease out the task of workers who are constantly involved in lifting heavy loads.

The prototype should not be too complex that the workers found it difficult to use it on a daily basis.

The time taken to complete the task, efficiency, and safety measures should not be compromised at the expense of the comfort that is provided by the load carrier

The prototype must not be such that it is applicability is limited by gender, height etc.

The prototype must not be such that it becomes difficult for the workers to find a place to keep it or to travel with it from one point to another. It should preferably be foldable to make easy to keep and transport

It should solve all the problems that are faced by already existing prototypes, like balancing of load, poor grip of trays, and appropriateness for women, carrier height and other design aspects etc.

The prototype must not be too expensive for the workers/contractors to buy.

OPTIMIZATION GOALS

After the field visit to all the respective places and getting the feedbacks for the existing prototype, we across various optimization goals.

Time: It is one of the important aspect which can be significantly improved. Traditional methods of load carrying require a huge amount of time. The use of load carrying device will reduce the time taken to complete the process and hence increase the frequency of load carrying.

Amount of Load: Efficient design of device will lead to increase amount of load to be carried then compared to the conventional method of load carrying.

Weight Distribution: Right now the conventional method of load carrying leads to weight distribution in a particular part of the body. The load carrying equipment can be designed such that it will lead to distribution of weight in other parts too. This will decrease the muscular effort required for carrying the load.

User Comfort: The practices employed in the industry are not friendly to the workers. It is really very uncomfortable for the people for carrying the load. Use of straps would significantly improve the design of the equipment and will lead to user comfortability.

Safety: The conventional methods are not safe as they are not balanced, doesn`t have any support system and lead to severe injury in case of imbalance. The device can be designed such that it will increase the safety of the workers by ensuring better grip and support for load carrying.

WHAT WE AIM TO ACHIEVE?

The new design should be able to:
Relieve the manual exertion on the labourer.
Allows the labourer to single headedly do the work.
Increases time efficiency
Balance
Reduces the weight supported by the labourers body

Decision Tree

Proof of Concept & Feedback on concept

This was based on modifications on previous design. The one by Sachin Panchal.

PROS

Corrects the issues prevalent in last design.
The wheels do not disturb the laborer.
Waist grab-to distribute load equally on waist
Belt to tighten load around
Shoulder beams to distribute load back and front
Adjustable head height for different heighted people
Extrusions to make sure that the weight doesn’t fall down.

CONS

⦁ Too similar to the current design which is clearly not in use

This design has weight on the bottom. As the operators rolls on the side the load comes up easily using pulleys.

PROS

Can be operated single handedly
The worker doesn’t need to put much effort

CONS

Complicates the system
There’s no need to keep the load down when it ultimately had to come up,
Some Other Sketches:

Insights from the interaction

Design 1:

Pivot joints of the load carrying part at different heights instead of making them rigid
Use of stoppers for controlled motion of levers
Appropriate spacing of levers to maintain the balance of load carrier
Use hollow 1 inch diameter pipes for making the frame
Use 25mm by 6mm rectangular pipes as stiffeners.

Design 2: