pic: Team 48 - Lock n' Load

[Orion.DeYoe]

That's impressive. What are you doing in terms of spring force? What's the weight of the ram? What's the starting gap between the ram and the ball (if any)?

[cbale2000]

It reminds me of a MK19 grenade launcher...

[Travis Hoffman]

Originally Posted by Orion.DeYoe

That's impressive. What are you doing in terms of spring force? What's the weight of the ram? What's the starting gap between the ram and the ball (if any)?

Currently, there are two www.centuryspring.com #81153 springs on there, providing about 50 lb. of force each in the low power setting, and 80 lb. of force each in the high power setting.

The high power shot is selected by extending the 2 3" stroke cylinders, which adds 3" of pre-load onto the springs.

The motor/gearbox pulls the springs back to firing position (roughly 6" of pullback). When the launcher fires, the majority of the stroke takes place with the ball in contact with the ram.

The ram is 1" round igus aluminum rod with a McMaster 3/8" wide, 20 DP, 14.5 PA rack gear affixed. The rod slides through two open-top igus linear bearing pillow blocks. I actually don't know how much the ram weighs. The overall claw/launcher combo projects to weigh around 35 lbs.

Originally Posted by cbale2000

It reminds me of a MK19 grenade launcher...

I was kinda thinking a .30 or .50 cal machine gun, but I think I like yours better. :-)

[Procolsaurus]

Holy Perspective! It looks like its 4 feet tall

[Travis Hoffman]

Originally Posted by Procolsaurus

Holy Perspective! It looks like its 4 feet tall

The main structural element is 4" x 4" x 1/8" wall aluminum, if that helps.

[BBray_T1296]

Fixed

[bEdhEd]

Originally Posted by Travis Hoffman

The main structural element is 4" x 4" x 1/8" wall aluminum, if that helps.

Our linear launcher (not actually a puncher, but similar) uses aluminum extrusion with those same dimensions as its main structure, and our winch gear system is integrated, so our aluminum box structure serves both as a gearbox and launcher track all in one piece. Since our launcher stores a ridiculous amount of energy, we now understand that these types of ball shooting mechanisms may just need that much structure!

[mschwab013]

That is terrifyingly awesome. Great job as always!

[DampRobot]

Originally Posted by Travis Hoffman

Currently, there are two www.centuryspring.com #81153 springs on there, providing about 50 lb. of force each in the low power setting, and 80 lb. of force each in the high power setting.

The high power shot is selected by extending the 2 3" stroke cylinders, which adds 3" of pre-load onto the springs.

The motor/gearbox pulls the springs back to firing position (roughly 6" of pullback). When the launcher fires, the majority of the stroke takes place with the ball in contact with the ram.

Wow, that's surprisingly little force for such a great launch. We're hitting 220 pounds at full pullback in our shooter, and we're still not getting much distance as we want.

Any reason for the tiny little pusher plate? Or are you going to replace this with something else?

[Travis Hoffman]

Originally Posted by DampRobot

Wow, that's surprisingly little force for such a great launch. We're hitting 220 pounds at full pullback in our shooter, and we're still not getting much distance as we want.

We're pretty happy with the efficiency. I cannot imagine it is the only reason, but our rack and pinion cocking system completely disengages the cocking pinion from the rack on the plunger rod - the pinion has missing teeth by design - so there is no drag on the plunger rod from a winch when it fires forward.

The igus linear bearings and aluminum shaft are also (literally) quite slick.

Any reason for the tiny little pusher plate? Or are you going to replace this with something else?

Honestly, the shape/size was kinda arbitrary - we just wanted something larger than the diameter of the 1" plunger rod to start. The end of the rod is threaded so we can put in larger-diameter endcaps if we want and examine the effect on distance (and more likely, shot consistency).

[Wayne Doenges]

Hi Travis

How far are you hitting the ball?

[Orion.DeYoe]

This looks like a really long shot but I'm assuming that the camera perspective affects it a bit. What is the maximum effective range of this launcher?

[Travis Hoffman]

Originally Posted by Wayne Doenges

Hi Travis

How far are you hitting the ball?

Our low power shot was hitting from about 16' tonight.

[DampRobot]

Originally Posted by Travis Hoffman

Our low power shot was hitting from about 16' tonight.

Is that shots from 16' into the goal, 16' to hit the ground, or something else?

[johnr]

I know nothing is going to happen but i sure would like to see a steel cable thru the center of that spring. I just don't see a way to hook one up in this picture. Maybe once it is mounted. I worked on garage doors for 30 years. Please be careful.