2012 Discussion

A discussion all encompassing the design there will be threads created for subsystems

If the part number above doesn't come up with anything, anything that matches the last entry in the chart will do, preferably with hardened teeth


On Sun, Jan 8, 2012 at 8:09 PM, ken wong <ken.qwerty@gmail.com> wrote:

if they cant get a 1/2" bore, there are smaller bores available.


On Sun, Jan 8, 2012 at 8:00 PM, ken wong <ken.qwerty@gmail.com> wrote:

ya for sure,
3.5 degrees of caster will give us a 0.038" difference when turning 45 degrees, anything more and the tread wont be contacting the floor. this may be all we need because we have a low gear and there is going to be less weight on the slightly lifted wheel.
also, we have to call oshawa bearing or oshawa gear tomorrow to see if they can get the bevel gears, the part number is B0025Q1XXa:

Boston Gear L101Y Miter Gear, 1:1 Ratio, 20 Degree Pressure Angle, 0.500" Bore, 12 Pitch, 15 Teeth, Steel



On Sun, Jan 8, 2012 at 6:45 PM, David Smith <david.smith22@sympatico.ca> wrote:

Since the team voted on swerve today the one thing we did not talk about is one of its negatives,

Doing 360 spins

I would like to see if a few degrees of caster with the wheel offset helps.
Can you draw up something to see if a few degrees gives us about 1/16 lift
which would mean the wheel on the other side is going down the same amount so the total distance would be about 1/8 inches.


I also think that maybe all of this communicating between you and I should be on the forum for all to see.
Can you cut and paste what we have been discussing onto the forum?

From: ken wong
Sent: Sunday, January 08, 2012 6:32 PM
To: David Smith
Subject: Re: Design

The fisher price motor is actually 271w, and spins at 20770rpm
I also did some quick calculations and using a 5/8" shaft, the farthest we could fire a ball is 30 metres, or 100ft at 45 degrees without accounting for air resistance or crushing the ball or the rollers slowing down. to clear the entire field, the motors would need to run about half speed without taking into account the above factors
Although this is the range from the height of the robot, it tells us we should have more than enough power. from here i think its time for a test, we can do the split shaft with a hole in it with one of these clamp on shaft collars in the final version: http://www.mcmaster.com/#shaft-collars/=fpzt4x
there is also a lot of recoil, the rollers will accelerate the ball at a maximum rate of 28m/s^2, wich will give 1730N of recoil if the rolls dont slow down.

Firing the entire field with directly driven shafts is a possibility although i cant calculate the drop in rpm, to dampen the effect of slowing down, some aluminum flywheels could be added, or more motors.

I can bring in drawings for the swerve plates tomorrow so people know what they will be doing

On Sun, Jan 8, 2012 at 9:50 AM, ken wong <ken.qwerty@gmail.com> wrote:

I considered a lot of the things you said last night already, I have good ground clearance but the skid plates are and issue if we want the maximum possible pickup width.

On Sun, Jan 8, 2012 at 9:34 AM, David Smith <david.smith22@sympatico.ca> wrote:

I just thought of a problem
going over the 4” bump and having a conveyor or pressure plate down low
I have few ideas but I have not yet thought them out.

From: ken wong
Sent: Sunday, January 08, 2012 2:10 AM
To: David Smith
Subject: Re: Design

Or maybe the plastic pillow block bearings weith some pvc, i have some sketches and basic cad tomorrow.

On Sun, Jan 8, 2012 at 1:36 AM, ken wong <ken.qwerty@gmail.com> wrote:

we can use those crappy bearings we got for the conveyor rollers


On Sat, Jan 7, 2012 at 10:51 PM, ken wong <ken.qwerty@gmail.com> wrote:

NSK does sell 1/2" or 12.7mm tapered bearings, they are rated for 10700N, i cant even find the spec on the flanged bearings we are using, this does mean a bearing block though.



On Sat, Jan 7, 2012 at 9:55 PM, ken wong <ken.qwerty@gmail.com> wrote:

one thing that concerns me is the load on the 1/2" flanged bearins when flying over the bump, we should do a hammer test to see if they fly apart tomorrow, if they do we might need a thrust bearing or a tapered bearing... i trying to find the max thrust load right now


On Sat, Jan 7, 2012 at 7:11 PM, ken wong <ken.qwerty@gmail.com> wrote:

I really want think the frame out carefully to make it as simple as possible, milling another narrow piece would probably be easier since we will be attaching the gearboxes and a new steering assembly, this frame could be very complex and every detail should be taken into account.

The shooter should have enough power to get to the top basket for sure, but if there is a robot blocking I think we should be able to shoot over them. also, we ARE allowed to place basketballs on the field from what i see, rule <G03>Items other than Robots and Basketballs shall not be placed on the Court prior to or during the Match.
also basketballs start on our bridges and any unused balls go to the middle bridge, from either alliance.

tomorrow we should have a crash course on reading orthographic drawings so the newish team members wont need as much assistance. after some brainstorming.


On Sat, Jan 7, 2012 at 7:00 PM, David Smith <david.smith22@sympatico.ca> wrote:

If we decide on swereve we can use a 2” by 2” piece of aluminum or more
for the frame rails and cut them down in the middle areas to 1x2. we can then weld on a plate where we cut them out to make them four sided again.
This would not be difficult.

2nd option
A 1x2” tube going to each side and having blocks added on the bottom of each end.
We could even use what we already have for frame rails.

I like option 2

I also think our high speed lift should have the ability to shoot the balls a short distance so we can make the top row.