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
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
Length to peak point 4 3/4"
Height at peak point
Slide wedge under the door to hold it open.
For Number Hinges
The surfaces to consider would be:
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
Welght Msh nody materly
vary accordingt the ambient emporatu general the
tember rature decreases. the because the viscosity of
temperature When inceratu normal the
damper charactenstes will returnto nermal 39 weil
2 The werking ofthe hingeis 120° Opcrating the
hinge beyond this anglo will causo demago tothe hinge
(Ambient temperature C)
Sketch of the system
Calculations. Create a table to contain the result for all scenarios
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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
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.
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....