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A childcare center needed to improve the security of their parking lot due to the unwelcomed trespassers and installed a gate. After they installed the gate they encountered a problem with the gate being too heavy and difficult to open. Whenever the children’s parents are coming to pick up their children the teacher has to open/close the gate manually which is a time-consuming process due to the weight and the structure of the gate. Therefore they have reached out to us to help improve the security system and ease the use of the gate.
The present gate is too heavy to be easily maneuvered. We need to redesign the hinge mechanism and automate the opening and closing of the gate by remote.
1. The gate must be automatic
2. Children must be able to open/close the gate (remote control)
3. Must change the hinge system
4. Must be able to open/close the gate during winter (snowy and frosty days)
5. The gate must be lockable
6. Must be easily maneuvered
7. Must be long enough to cover the entire entrance (approx. 20 feet)
8. The gate has to be installed on uneven ground
9. Power must be pulled from the childcare building
10. The mechanism must be strong enough to open/close the heavy gate
There are a few types of gates that we thought about. One of them would be a sliding gate. The advantage that a sliding gate has is the open/close motion. The drivers don’t have to be careful about being hit by the gate. This model wouldn’t work for our situation because the gate is placed on uneven ground.
Another type of gate would be a double swing gate. With most of the gates found online of this type we ran in the same issue, they are built for even ground.
The third type of gate that we were looking at was the barrier gate system. As for all other types presented here, the price of this gate is over $1500 without including the automation and anything else we need to finish the project. We also have to consider the length of the gate, which is longer than normally sized barrier gates.
After analyzing all the design concepts, we decided to go with concept 2 but modified to meet our given specifications.
Because of the high price of steel, we decided to use the old gates. The old gates had a sleeve attached to them which connected the gate to the fixed post. We decided to cut the sleeve off and replace it with a steel rectangle to which we will weld hinges and finally assemble it to the post. The gate next to the school will be automated while the opposite gate will not, as requested. An electric motor will be used to open/close the gate which will be powered by a 12V battery charged by an AC transformer.
For analysis 1, we found the stress in each hinge and compared it to the maximum stress the hinges could withstand, to make sure our gate would operate without failure.
For analysis 2, we decided to calculate the mobility to confirm our belief that our gate would be a one degree of freedom mechanism.
Then we calculated the torque needed in order to make the gate move.
F = M*G, F = force, M = mass, G = gravity, M*G = W, W = weight.
T = F*r, r = radius.
W = 99 lb, r = 5.5 ft
F = 99 lb, T = F*r = (99)*(5.5) = 544.5 lb/ft.
After finding that calculate we looked for a motor that could supply that amount of torque, so it could move the gate.
We find the Mighty Mule gate opener that Generates 680 lb/ft of torque at 12 V.
After installing the gate, we programmed the remotes and instructed the teacher how to use it. We tested the gate and it was opening/closing as we expected.
For safe use of this gate, please do not sit or climb onto the gate. Also when gate is opening stay clear of its swinging path. Do not try to open the gate while it is locked. To open the gate, point the remote at the antenna that is on the pole by the gate. Click it once to open it and do not attempt to close it till it has fully opened and come to a complete stop. Please make sure there are no cars or objects in the gates path, it could cause some small damage! Make sure to keep the gate lubricated with grease every 4- 8 months so it will open properly.
This project was what we all wanted to experience while doing school, real-life experience. We learned how to work as a team, to finish work at a certain deadline and most important, how to apply engineering skills in the manufacturing process. We want to thank Dr. Canfield for this opportunity and also Jeff Randolph and Justin for their help with the project.
