A Project Report on

WALKING FRAME WITH SITTING ASSISTANCE

Submitted By:

TARASH RAJPUT

VIVEK SHARMA

AKHIL CHAWLA

2003-2007

Department of Mechanical Engineering

Punjab Engineering College, Chandigarh

(Deemed University)

Chandigarh 160012A Project Report on

WALKING FRAME WITH SITTING ASSISTANCE

Submitted toward partial fulfillment of the requirement for award of degree of Bachelor of Engineering in Mechanical Engineering in academic year 2006-2007:By:

Tarash Rajput

031654

Vivek Sharma

031660

Akhil Chawla

031661

Under the supervision of:

Dr. RAJNESH TYAGI

(Faculty, Mechanical Engineering Department)

Department of Mechanical Engineering

Punjab Engineering College, Chandigarh

(Deemed University)

Chandigarh 160012PUNJAB ENGINEERING COLLEGE: CHANDIGARH 160012

BONAFIDE CERTIFICATE

It is certified that this project report titled WALKING FRAME WITH SITTING ASSISTANCE is the bonafide work of TARASH RAJPUT, VIVEK SHARMA & AKHIL CHAWLA who carried out the project work under my supervision. SIGNATURE

SIGNATURE

DR. P.B. MAHAPATRA

DR. RAJNESH TYAGI

HEAD OF THE DEPARTMENT

PROJECT INCHARGE

FACULTY

MECHANICAL ENGG. DEPTT.

MECHANICAL ENGG. DEPTT.

PUNJAB ENGINEERING COLLEGE,

PUNJAB ENGINEERING COLLEGE,

(DEEMED UNIVERSITY)

(DEEMED UNIVERSITY)

CHANDIGARH-160012

CHANDIGARH-160012 ACKNOWLEDGEMENTWe would like to thank the project coordinator Dr.RAJNESH TYAGI, for providing all the material possible and encouraging through out the course. It is great pleasure for us to acknowledge the assistance and contributions of our Head of the Department Dr. P.B. MAHAPATRA, for his prompt and timely help in the official clearances and valuable suggestions during the development of this project.Last but not least, we express our heartiest gratitude to Almighty god, our Parents for their love and blessings to complete the project successfully.

Date:

Tarash Rajput

Vivek Sharma

Akhil Chawla

ABSTRACTThis report has attempted to modify the general design of the walking frame used for assisting in walking. Walking frame is a supporting frame for the old aged and handicapped people which are either unable to walk or face difficulty in walking. But, while assisting in walking, the conventional walking frame lacks on the basis of that, it do not support in sitting. Accordingly, there is a need for improved designs of the walking frame, so that it should also assist the person in sitting. So, a conventional walking frame has been modified by designing a new walking frame installed with shocker and springs, which results in adjustable height mechanism of the walking frame and they get compressed by the weight of the person and helps in sitting. The minor problems have been documented for possible future improvement. CONTENTS PAGE

LIST OF TABLES ...........................................................viii

LIST OF FIGURES ..........................................................ix1. INTRODUCTION: ........................................................1

1.1 Problem statement....................................................11.2 Background........................................................ 1

1.2.1. Purpose of walking equipment1

1.2.2. Design of walking frame.1

1.3 Objective..31.4 Method of approach...3 1.5 Force analysis..41.6 Our approach5

1.6.1 design 1.5

1.6.2 design 2.6

1.6.3 design 3.7

1.6.4 design 4.8

1.6.5 design 5.9ACTUAL PICTURE102. MANUFACTURING PROCESS........................................ 11

2.1 Material selection.................................................11

2.2 Structure of the frame...............................................122.3 Process.12

2.3.1 Cutting of pipes..12

2.3.2 Bending of pipes.132.3.3 Fabrication of pipes.142.3.4 Other operations..152.3.5 Assembly.163. WORKING.................................................................. 17

LIST OF TABLESBill of material..11

LIST OF FIGURES

Simple walking frame 1 Foldable walking frame......2 Adjustable walking frame...2 Wheeled walking frame with brakes...2 Picture showing force analysis....4 Picture showing computer generated design 15 Picture showing computer generated design 26

Picture showing computer generated design 37

Picture showing computer generated design 48

Picture showing computer generated design 59

Actual picture..10

Picture showing horizontal cutting machine...12 Picture showing manual bending machine..13

Picture showing a schematic of MIG welding14 Picture showing knob..15

Picture showing gas shocker...15

Picture showing working..17-20

1. INTRODUCTION:1.1. PROBLEM STATEMENT:Walking frame is a device used to support an elderly or infirm person while walking. The problem was to modify the walking frame so that it should also assist in sitting along with walking assistance. This problem was of our interest because it is related with serving the mankind as it is solving a problem by assisting the needy in sitting, otherwise there is no means provided for sitting, a person sit slowly by holding the supporting rods of the walking frame. So its very difficult for a person to sit who is suffering from pain in his/her joints.1.2. BACKGROUND:1.2.1. PURPOSE OF WALKING EQUIPMENT:Walking equipment is used for two purposes: as part of a rehabilitation programme when the user is recovering from an injury or operation; and as a long-term aid to mobility when the user has a permanent difficulty with walking. The rehabilitation process is a gradual progression towards independent and unassisted walking and may commence with the use of a walking frame to give the user confidence.

1.2.2. DESIGNS OF WALKING FRAME:

Now, various designs of the walking frame have been put forward till now and are into use. But no one emphasized on the sitting assistance, although, no doubt that they have made walking very comfortable. Various types of walking frames available are:

SIMPLE WALKING FRAME: It is just a rigid frame and is very light in weight but no additional feature is there FOLDABLE WALKING FRAME: This type of walking can be folded and it saves a lot of space when not in use. The saving of about 80 percent of space can be obtained.

ADJUSTABLE WALKING FRAME: This type is also widely used as its height can be adjusted. WHEELED WALKING FRAME WITH BRAKES

So, it can be very well judged that nothing has been done earlier for sitting assistance. 1.3. OBJECTIVE:

Our objective was:

To serve the mankind

To design and manufacture a walking frame which should also provide sitting assistance along with walking assistance to the person

To provide a means of sitting to the people who are advised to take support of walking frame

1.4. METHOD OF APPROACH:

Before reaching the final solution to the problem, various designs were prepared, worked upon and rejected. The following factors were studied and taken care while preparing a design for walking frame.

Designed to be picked up by the user, therefore needs to lightweight.

Most appropriate for those with poor walking abilities or poor balance.

For use in indoors and for shorter distances.

It should be rigid. It should provide stability by providing wider supports base. Should allow sitting assistance by adjusting its height whenever a person wants to sit down. It should provide sitting assistance without shock. Its height should be adjusted in a way which should not involve much application of force by the person. It should be able to increase the confidence of user in his/her walking and sitting ability.

Stability is one of the major factors in case of a walking frame design, as it takes the load of a person while assisting in performance. So, its joints should be rigid and its height base width and weight should be carefully considered while designing stage.1.5. FORCE ANALYSIS:Proper force analysis of the walking frame design should be done before finalizing. As shown in the figure below, there are three types of forces

Above shown in the figure is an illustration of the vertical (Fy) and anterior (Fx) forces applied to a typical walking frame. Fx applied at the walker hand grips creates a "moment of force" that tends to tip the walker forward over its front two legs. As long as this forward tipping moment is less than the moment created by Fy applied at a perpendicular distance (r e) from the front two walker legs, the walker

will not tip forward.Where:

WTI = Walker tipping index, it gives the measure of stability of the walkerFy = Vertical walker-to-floor force

Fx = Horizontal walker-to-floor force acting perpendicular to axis connecting 2 walker legs (rp) perpendicular distance of walker center of pressure to axis connecting 2 walker legs

Walker height = Height of walker handgrips above floor1.6. OUR APPROACHConsidering the various above requisites for the design of walking frame, we created two designs before reaching to a final design.

1.6.1. Design 1

As shown above was the first design created by us. The principle of its working was a hydraulic mechanism. We decided to install a hydraulic pump or an electric motor to the walking frame which would help in upper and lower movement of the arms of the walker. But this design was rejected because it was not at all feasible on account of following points: Even a smallest hydraulic pump or motor would weigh 2.5-3.5 kg. So, it didnt satisfy the condition that the walking frame should be light weight. It is not possible for the user to lift such a heavy walking frame, as it does not have tires.

To install a hydraulic pump, a sufficient space is required, so it was also a constraint in design.

It would have been too costly due to installation of pump or motor.

Hydraulic oil leakage could cause severe damage while sitting

1.6.2. Design 2

In this design, we dropped the idea for hydraulic pump or electric motor and we thought of installing a shocker for the upward and downward movement of the arms of the walker for adjusting height, so that a person should be able to sit by moving himself/ herself down along with the arm. But this design was also rejected on the basis of following points:

As arms have no firm base, it would have caused instability to the structure.

As the shocker installed is vertical, therefore comparatively less space was left for the users movement.

We were to use knuckle joint for the arm movement, which is sometimes very difficult to operate for a handicapped person.

The load on the shocker was uneven since arms are free at one end.

1.6.3. Design 3

This was a modification in the previous design as the support arms were provided to the gripping arms for support, so that gripping arms should get a firm base but this idea was also dropped due to following constraints:

The gripping arms got the firm base but still, there was a chance that the arms might go down with a sudden jerk or shock while sitting due to application of the users weight.

The shocker still remained vertical; therefore users movement was still restricted.

1.6.4. Design 4

Now, after rejecting the third design, we considered the conventional design of the walking frame. We decided that it would be better that if the whole upper frame would move up and down instead of moving a jointed arm. This will provide greater stability to the frame as the weight of the person will be equally distributed to all the four legs of the walking frame. This design was put into manufacturing but later on, a small modification was done in the design because its locking arrangement was not found satisfactory. The reasons were:

The locking arrangement as seen in the figure is a L-shaped object where the horizontal metal strip can rotate about the fixed one and it is taking much space on both sides. So this was the constraint, this design was rejected. Another reason was, while walking, this L-shaped arrangement was supposed to hold the upper frame firmly so that it should not move down but while walking the horizontal metal strip could rotate.

1.6.5. Design 5

After considering the previous designs, and their constraints, we came at a final solution to the problem. Two modifications were done in the previous design:

The L-shaped locking arrangement was replaced with two knobs attached with the guides. They can be tightened easily before walking and when a person needs to sit, they can be loosened.

Another change was that, we put 4 helical springs( 2 in each leg) in the rear legs of the walker whose total tension were equal to that of the shocker.

So, this design was found satisfactory and is manufactured. The actual picture of the walking frame is shown below:

ACTUAL PICTURE

2. MANUFACTURING PROCESS2.1. Material selectionBefore selecting a material, following points were considered: It should be a hollow pipe

It should be light weight

It must have high strength

Cost consideration

So, various types of materials were considered before selecting, for example:

Aluminium

Aluminium alloys

Thin MS tube

All the materials were available but we selected thin mild steel tubes for manufacturing.

2.1.1. Bill of materialPart nameMaterialDimensionsQuantity

PipeMild steel72 inches, dia = 25.4 mm2

PipeMild steel18 inches, dia = 24 mm2

PipeMild steel14 inches, dia = 24 mm2

GuidesMild steel12 inches, dia = 28 mm4

Hand gripPlastic2

KnobMild steelDia = 7mm tapping2

Gas shocker1

Helical springStainless steel 302O.D.= 22 mm4

ShoeRubberDia = 25.4mm4

BoltsMild steelDia = 12 mm2

2.2. Structure of the frame

The frame consists of a number of parts. They are briefly described below:2.2.1. Lower base frame

As shown in the picture above, is the computer generated image of the lower base frame of the walking frame. The guides are welded to it to provide the accurate motion of the upper gripping frame into it.

2.2.2. Upper base frame

The upper gripping frame of the walking frame is shown in the picture above. This part was separately welded to move inside the inner part with the help of guides which will bear the entire load and transfer the load to the compression springs inside the inner base frame.

2.2.3. Gas shockerThe shocker used in the walking frame is a gas shocker and is an Armstrong type of shocker which is generally used in the car suspension systems. Its picture is shown below:

Its working is also described with the help of the following diagram.

Upon application of load on the upper mount, the piston rod moves in to compress the gas or oil present inside the pressure tube and upon releasing the load, it regains its original position as the pressure gets lowered and oil or gas expands.2.2.4. Compression springs2.3. Process2.3.1. Cutting of pipesThe first operation was to cut the MS pipes into desired lengths. This was done with the help of the sawing machine at the place from where they were purchased. Two pipes of 72 inches, diameter 25.4 mm

Two pipes of 18 inches, diameter 24 mm

Two pipes of 14 inches, diameter 24 mm

Four pipes of 12 inches, diameter 28 mm

The horizontal cutting machine was used as shown in the figure below:

The above shown figure is of a circular sawing machine. It is used for cold-sawing of the metal. Its diameter is 750mm and it is made solid with integral teeth. It is used for material cutting which may be rectangular or circular in cross-section. 2.3.2. Bending of pipesThe next operation was bending of pipes. Bending of pipes was required for making the upper frame as in this design, the whole upper part will move down, upon application of load and lower base frame will slide inside the upper frame as the diameter of pipes used in lower frame is 24 mm and that of upper frame is 25.4 mm.

Bending of pipes was done on the bending fixtures as shown in the figure below:

The fixture shown above is basically a manual bending machine. The pipes are put in and are tightened and by applying manual force against the round disc, the desired shape of the pipe can be obtained. The bend shown below in the picture is gripping arm of the walking frame and it was obtained by the above shown manual bending machine.2.3.3. Fabrication of pipesThe next step was the fabrication of pipes. Fabrication was necessary for making lower base frame and upper gripping frame, which were to be fitted into each other later with the help of guides. Fabrication of pipes was done with the help of MIG welding technique.

2.3.3.1. MIG welding

MIG (Metal Inert Gas) or as it even is called GMAW (Gas Metal Arc Welding) uses an Aluminium alloy wire as a combined electrode and filler material. The filler metal is added continuously and welding without filler-material is therefore not possible. Since all welding parameters are controlled by the welding machine, the process is also called semi-automatic welding.

The MIG-process uses a direct current power source, with the electrode positive (DC, EP). By using a positive electrode, the oxide layer is efficiently removed from the Aluminium surface, which is essential for avoiding lack of fusion and oxide inclusions. The metal is transferred from the filler wire to the weld bead by magnetic forces as small droplets, spray transfer. This gives a deep penetration capability of the process and makes it possible to weld in all positions. It is important for the quality of the weld that the spray transfer is obtained. There are two different MIG-welding processes, conventional MIG and pulsed MIG:

2.3.4. Other operationsVarious other small operations were done which are listed and described below: Drilling: Two holes (each 0.7 cm) were drilled on the front guides for the locking arrangement. A nut was welded on each hole and knobs were inserted. These knobs are the locking system for the walking frame. Knobs can be tightened to restrict the movement of upper gripping frame when user has to walk and they can be loosened while sitting. The position and working of knob is shown in figure below:

Grinding: The next operation was grinding operation, which was done with the help of a hand grinder. Grinding was required for removing grains of metal which were produced during welding of different parts and also for imparting good finish to the parts. Fabrication of metal strips: 4 small metal strips with 1.2 cm drill hole were also welded on the front pipes (two metal strips on each pipe) for holding the shocker in-between them. Shocker was attached with the help of nut bolt arrangement. this is shown in the picture: Insertion of spring in the rear legs: Two compression springs each, were then inserted in the rear legs whose tension were equal to that of the shocker. Their spring constant was 5.4 lb/in. after the springs were inserted, the pipes were welded with a circular plate from below so that springs should not come out.2.3.5. Assembly Next and the final operation was the assembly of the various parts produced. The total number of the parts was:

Upper gripping frame

Lower base frame

Shocker

Shoes

The guides were then welded to the legs of the inner base frame and the upper gripping frame was put into it. The shocker was then inserted into the welded metal strips and was bolted. Then shoes were put on all the four legs and then the whole frame is painted black in colour.

3. WORKINGThe working of the walking frame is shown below with the help of following pictures:

Picture 1: User walking with the support of walking frame

Picture 2

Picture 3: User loosing the knobs for sitting

Picture 4: User putting his weight on the walking frame for sitting. The walking frame gets compressed.

Picture 5: The frame gets completely compressed

Picture 6: User sitting comfortably and the frame gaining its original position due to restoring force of the springs and the shocker.

Picture 7: User tightening the knobs before getting up.

Picture 8: User getting up with the support of the frame.

PAGE 13