1. E NGINEERING D ESIGN Contents: Automatic Door Closer

2. P ROBLEM D EFINITION / N EED S TATEMENT To reduce the load on AC To reduce disturbance like sounds. Common places inneed of automatic door closing facility 1. Hotels/ restaurants and lodges 2. ATM counters 3. Banks- managers cabin doors 4.Elevator doors 5.Clinical Laboratories and Hospitals. 6.Protection from Fire, dust, smoke, odour etc. 7.Computer labs and sophisticated machinery labs.

3. P ROBLEM S TATEMENT Design a door closer which closes the door automatically.

4. D ESIGN CRITERIA : 1. Should not close the door rapidly, should have delayed closing, mainly during latching. 2.The device should be of low cost 3.The device should not trap the clothes of a passerby. 4.The device should not make unnecessary noise during opening and closing. 5.The device should be able to retrofit the existing door 6.The device should perform equally during all climatic conditions 7.The device should be light in weight. 8.The device should be able to access for all age groups. 9.The device should not obstruct the normal movement of the people 10.The device should be able to provide the door, swing angle of at least 90° from the initial closed condition. 11. The device should not consume power/Electrical Energy

5. S TEP 2: G ATHER PERTINENT INFORMATION : In order to make the door close automatically, what are the various techniques which can be adopted is studied in this Step. An investigation if done in this line of thought, the following information may be relevant. Many times it is observed that the door closes on its own due to improper hinge mounting or door frame being not mounted perpendicular to the floor surface and inclined in the opposite direction to that of door swing. A spring mounted between the frame and the door can close the door if the spring is subjected to tensile force while opening. In order to restore to its original free state, the spring pulls the door towards the frame and ensures the closing of the door. Spring controlled door closer with Fluid /oil filled cylinder having two chambers in order to ensure delayed closing. A cord carrying a dead weight mounted over a pulley fitted to the top of the door. A sensor based sliding door mechanism for automatic door closing and door opening. Roller ended spring loaded device.

6. S TEP 3: G ENERATE M ULTIPLE S OLUTION : This is a very creative step in the entire design process and is based on the second step where identification of various techniques to solve the given design problem is done. Since generation of multiple solutions is based on the literature survey done in the previous step following list indicates probable alternate design solutions.

7. D ESIGN SOLUTION OPTIONS : Option1: Mounting the frame slightly inclined. This option takes the advantage of gravity and works well except for generation of latching force. So no latching can be ensured. Option2: Spring loaded door closer. A coil spring can be inserted which will restore to its free state tension once the door is released after opening. Option 3: Hydraulic door closer: Option 4: Cord over a pulley and dead weight mechanism: Option 5: Proximity sensor based sliding door mechanism Option 6: Roller ended spring loaded mechanism.

8. S TEP 4: A NALYSE AND SELECT A SOLUTION The technical knowledge and experience is applied to evaluate the alternate solutions identified in the previous step. Functional Analysis: All the design solutions do function as expected but with varying degree of comfort while opening and closing. Option 1 cannot ensure the latching ( No additional force) Option 4 and 6 have limitation to retrofit on glass doors Option 6: Pushing the door for opening may be stress full while opening the door fully as the spring will be under very high tension. Option 5: consumes additional power and needs a control circuit and battery backup. Highly sophisticated.

9. Ergonomic Analysis: Option 4 and 6 will not be aesthetically pleasing. Deficiency in option 1 may go unnoticed. Option 6: Stressful to open the door fully Option 2 and option 6 closes the door too rapidly.

10. Product safety and liability: Option 4: has inherent problem of moving dead weight causing injury to the users while sudden opening and also if the users pushes door towards the frame, a banging noise may be produced. Option 2: Possibility of rapid closing and generating banging noise on the frame while closing due to high speed of closing.

11. A SSIGNMENT OF RATING FACTOR FOR PERFORMANCE OF EACH OF THE IDENTIFIED IMPORTANT ATTRIBUTES · Excellent 9-10 · Good 7-8 · Fair 5-6 · Poor 3-4 · Unsatisfactory 0-2 Important criteria (or desirable attributes) of the design and assigned weights are: Safety: 25 percent (25 points) Ease of use: 15 percent (15 points) Portability/Retrofit: 15 percent (15 points) Ensure latching : 15 percent (15 points) No Noise : 10 percent (10 points) No power consumption ( Passive): 10 percent ( 10 points) Cost:10 percent (10 points)

12. D ECISION M ATRIX : CriteriaWeight (%) Design1Design2Design3Design4Design 5Design 6 Safety R X Weight 259 225 5 125 10 250 4 100 10 250 7 175 Ease of Use R X Weight 1510 150 9 135 9 135 9 135 10 150 5 75 Portability/ Retrofit R X Weight 155 75 9 135 9 135 7 105 3 45 8 120 Latching R X Weight 153 45 7 105 10 150 6 90 9 135 9 135 No Noise R X Weight 109 90 8 80 9 90 3 30 9 90 7 70 No Power consumption R X Weight 10 100 10 100 10 100 10 100 3 30 9 90 Cost R X Weight 10 100 9 90 8 80 9 90 6 60 8 80 Total 100785770 940650 760745

13. Hence, the discussion on working principle of Hydraulic door closer.

14. H YDRAULIC D OOR C LOSER Door Closed Door Opened

15. H YDRAULIC DOOR CLOSER 1 Hydraulic door closer Inside details.

16. 1.Body 2.Plunger with rack 3.Main arm 4.Adjusting arm 5.Spindle 6.Pinion. 7.Adjusting Screw 8.End caps with washer 9. Valves 10. Spring.

17. H YDRAULIC DOOR CLOSER ( SECTIONAL V IEW )