# Objective: a) Study the effect of floor surface roughness instatic...

## Transcribed Text

Objective: a) Study the effect of floor surface roughness instatically stopping a door with spring loaded hinges by means of a doorstopper, while considering friction b) find the amount of the internal forces inserted on the top hinge shafts Project elements: The surface of the floor varies The doorstopper's material is rubber The door is installed on the door jamb by three spring loaded hinges. Specification of these two hinges is attached The specification of the door itself is provided within attached spec sheet Description: find the sum of forces and moments of the door and its hinges (neglecting the friction in the hinges). This will involve summing the forces from the hinges and the force of gravity. Since there are three hinges, there are three places where torque could happen. We also need to find the frictional force that will put the door into equilibrium when it hits the doorstopper. Then we have to find out which floor type provides better surface for use of rubber doorstopper. The distance between the doorstop and the edge of the door is for you to decide however you should keep it constant when switching between different floors for sake of consistency of your result Spec sheets: Door stop: Length to peak point 4 3/4" Width 2 1/8 Height at peak point 1 1/4' Color Black Material Rubber Mounting Location Floor Slide wedge under the door to hold it open. Door Door Width 47 3/4" Height 83 1/4" Thickness 1 3/4" For Number Hinges 3 Top Doorto Hinge (A) 4 7/8" Hinge (B) 37 1/8" Hinge (C) 69 3/8" Handle Cutout 42 3/4' Door Material Primed Steel Door weight 3501 Door Gauge 18 gauge Surface The surfaces to consider would be: Cement PVC Parquet 1 1 0.8 0.8 0.6 0.6 0.4 0.4 0.2 -+-Parquet 0.2 - - +-Epaxy -E-Ceramics 2 4 6 8 10 o 2 4 6 8 10 Surface Roughness.um Surlace Roughness.um Hinge The hinge would be spring loaded which applies atorque onthe door to close it. The hinges would have twotype of torques, forward and reverse What you need for your project would be the forwar torque R13 En 76.5 86 Specifications Welght Msh nody materly Oll yye 100 410g (2DC) siker SUS304 Gilicono Damper Charactentstics Damper 15 vary accordingt the ambient emporatu general the the the tember rature decreases. the because the viscosity of 10 temperature When inceratu normal the damper charactenstes will returnto nermal 39 weil F 5 10 20 30 40 50 2 The werking ofthe hingeis 120° Opcrating the hinge beyond this anglo will causo demago tothe hinge that implece (Ambient temperature C) Deliverables: Sketch of the system Calculations. Create a table to contain the result for all scenarios Discussion

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Introduction

The system considered in this project consists of a primed steel door attached to the wall by the means of three spring-loaded hinges, and a door-stop that is used to statically stop the door. The door-stop should be designed such that it is able to resist the torque provided by the hinges and prevent the door from closing. The floor and the stopper should be designed such that they are able to provide sufficient frictional force.

The aim of the project is to study the effect of floor surface roughness while considering friction, as well as find the amount of internal forces inserted on the top hinge shafts

Assumptions

1. Hinge model, FHD-A1-1-104, is used
2. While doing force calculations, vertical force is assumed to be shared equally by all three hinges
3. Since considering three hinges would make the system statically indeterminate, the horizontal reaction force at the hinge at the bottom is assumed to be zero.

Section A:

We know, from the catalogue, that the maximum torque that can be provided by this hinge is 5 Nm. Therefore, the total torque caused by three hinges combined: T = 5 x 3 = 15 Nm

Ideally, the door-stop should be placed at the extreme end of the door to maximize the torque contribution of the constant friction force. However, the door-stop might slip out of the door if it is placed at the extreme end. So, we place it at a distance, d = 45 inches from the edge of the door....

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