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Type: Posts; User: aakrusen

1. ## Thread: Help with rollers lifting an object

by aakrusen
Replies
8
Views
2,795

### View Post

964

Here's a basic picture of the 35° angle I am talking about. The tire is the large diameter circle and the two smaller circles are the rollers. The horizontal solid line is the ground and the...
2. ## Thread: Help with rollers lifting an object

by aakrusen
Replies
8
Views
2,795

### Am I on the right track? R = Resultant Force F...

Am I on the right track?
R = Resultant Force
F = Lateral Hydraulic Force
W = Tire Weight

W=R*COSΘ
F=R*SINΘ

Moving variables around and I get F=W*TANΘ, does that seem right?
3. ## Thread: Help with rollers lifting an object

by aakrusen
Replies
8
Views
2,795

### Thanks for the response. So you're thinking that...

Thanks for the response. So you're thinking that the PSI required by the hydraulic system is 1/2 * W * COSΘ?
W = 2000 lbs
Θ = 35°
0.5*2000*COS 35° = 819.15 lbs of horizontal force. Then as...
4. ## Thread: Help with rollers lifting an object

by aakrusen
Replies
8
Views
2,795

### The rollers are supported on the same frame as...

The rollers are supported on the same frame as the hydraulic system. The center of the roller is about 1.25" off the ground.

The rollers are on a bearing system, they'll spin with the tire as...
5. ## Thread: Help with rollers lifting an object

by aakrusen
Replies
8
Views
2,795

### OK, here's what I've come up with. I can treat...

OK, here's what I've come up with. I can treat the interaction with the tire and the roller like a ramp. I can take my known hydraulic pushing force (2651 lbs) and multiply it by the SIN Θ of the...
6. ## Thread: Help with rollers lifting an object

by aakrusen
Replies
8
Views
2,795

### Help with rollers lifting an object

I'm trying to design a hydraulic system that that will lift a tire on a car off the ground with a fixed roller and a sliding (laterally) roller driven by a hydraulic cylinder. In the picture below...
7. ## Thread: Slightly Different Scissor Lift, need help

by aakrusen
Replies
13
Views
5,709

### View Post

The face of the thread is at 14.5° from the perpendicular of the lead screw. The block that is sliding along the threads has a mating surface that is also at 14.5°. I don't know how to word it but...
8. ## Thread: Slightly Different Scissor Lift, need help

by aakrusen
Replies
13
Views
5,709

### I didn't think the lead screw had enough mass to...

I didn't think the lead screw had enough mass to cause a gravity sucking pull on the scissor system. While the screw will be spinning, is it spinning fast enough to to create an effective gravity...
9. ## Thread: Slightly Different Scissor Lift, need help

by aakrusen
Replies
13
Views
5,709

### Ok, the 6.28 is 2PI radians, right? This takes...

Ok, the 6.28 is 2PI radians, right? This takes my pitch (linear movement) and puts it over rotation, right?

Am I wrong in thinking the threads are helping me "push" the weight upward? If I...
10. ## Thread: Slightly Different Scissor Lift, need help

by aakrusen
Replies
13
Views
5,709

### Thank you. What is the 6.28 and how did you get...

Thank you. What is the 6.28 and how did you get that?
11. ## Thread: Slightly Different Scissor Lift, need help

by aakrusen
Replies
13
Views
5,709

### I think I need to give a little more info on what...

I think I need to give a little more info on what I want and why "C" isn't fixed in my design and how that works. The sizes of the arrows in my picture are not representative of the force acting at...
12. ## Thread: Slightly Different Scissor Lift, need help

by aakrusen
Replies
13
Views
5,709

### None taken, I should have provided more info or...

None taken, I should have provided more info or at least a sketch.

Hopefully this link will work.

547

The weight is on top at "W", the three points are marked as described in the original...
13. ## Thread: Slightly Different Scissor Lift, need help

by aakrusen
Replies
13
Views
5,709

### Am I not getting a response because this is super...

Am I not getting a response because this is super easy and you all are laughing at me for not figuring it out?
14. ## Thread: Slightly Different Scissor Lift, need help

by aakrusen
Replies
13
Views
5,709

### Slightly Different Scissor Lift, need help

I've seen several questions about the equations for a scissor lift but I need to see how the equation might be modified for a slightly different "scissor" design.

Let's use the red colored FBD...
15. ## Thread: Calculated shear stress, now what?

by aakrusen
Replies
2
Views
2,110

### Calculated shear stress, now what?

I'm designing a sprocket/motor hub and I've calculated the shear on the shaft from the hub to the sprocket. But, just to be sure, you could check the math.
Torque = 63.3 Nm
Shaft O.D. = 19 mm...

by aakrusen
Replies
4
Views
1,905

Thank you!
17. ## Thread: Known force, is it enough to move a car?

by aakrusen
Replies
4
Views
1,905

### Rubber tires, 24" dia, 36 psi.....I'm making...

Rubber tires, 24" dia, 36 psi.....I'm making these up. I understand that they play a role but I'm mostly looking for the equations (where I can put in the variable you mentioned and frictional...
18. ## Thread: Known force, is it enough to move a car?

by aakrusen
Replies
4
Views
1,905

### Known force, is it enough to move a car?

If I have 488 lbs of force, how do I determine if it can move a car that is in nuetral? Let's say the car weighs 4000lbs.
19. ## Thread: Need help with torque to force conversion

by aakrusen
Replies
14
Views
3,814

### So here's what I'm getting from the Engineer's...

So here's what I'm getting from the Engineer's Edge website:
T=(WK˛ * ΔN)/308t
WK˛=W(V/2*PI*N)˛
W=6000 lbs
V=44 feet/min
t=5 seconds
N=300
ΔN=300

I come up with .64 lb-ft of torque to move...
20. ## Thread: Need help with torque to force conversion

by aakrusen
Replies
14
Views
3,814

### Kelly, Thanks for the links, there's a lot of...

Kelly,
Thanks for the links, there's a lot of good info in them, it might have what I'm looking for. At the very least I think it will help me set up me equations.
21. ## Thread: Need help with torque to force conversion

by aakrusen
Replies
14
Views
3,814

### No biggy, I would have come to sites like this...

No biggy, I would have come to sites like this when I was in school if I knew about them. But then again, when I was in school I was doing this stuff everyday and I would have been able to do the...
22. ## Thread: Need help with torque to force conversion

by aakrusen
Replies
14
Views
3,814

### This isn't an assignment. This is part of a...

This isn't an assignment. This is part of a prototype design I'm working on.
The fact that I've been out of school for 6 years and haven't really used these type of equations since is why I need...
23. ## Thread: Need help with torque to force conversion

by aakrusen
Replies
14
Views
3,814

### Need help with torque to force conversion

Scenario:
Electric motor, 30 ftlb @ 300 rpm
6000 lb load (13200 N) fixed to "this" machine
Motor drives a shaft that drives tracks (like a tank)
Will need to go up an incline (0 - 10°)
Weight of...
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