VexPro Pancake Shifter Question

[brianbond]

Can't seem to find a definite answer on the size of threading for the fittings on the pancake shifter. Never ran one in the past so just trying to figure it out. If anyone knows I would love to know!

Thank you all!!

Brian Bond

[artdutra04]

Originally Posted by brianbond

Can't seem to find a definite answer on the size of threading for the fittings on the pancake shifter. Never ran one in the past so just trying to figure it out. If anyone knows I would love to know!

Thank you all!!

Brian Bond

The pneumatic fittings for the 3/4" 1/2" stroke pancake cylinder use #10-32 thread and are available here:
http://www.vexrobotics.com/217-2907.html

All dimensions for the cylinder are located on page 9 of this pdf:
http://content.vexrobotics.com/docs/..._Datasheet.pdf

[ohdan56]

Would one of you be so kind as to explain to me the use/application of a pancake shifter? I am not familiar with this equipment. How does gearbox interact with the pneumatic cylinder? Thanks, I'm learning!

[geomapguy]

Originally Posted by ohdan56

Would one of you be so kind as to explain to me the use/application of a pancake shifter? I am not familiar with this equipment. How does gearbox interact with the pneumatic cylinder? Thanks, I'm learning!

http://www.chiefdelphi.com/forums/attachment.php?attachmentid=15805&d=1389406671


http://www.chiefdelphi.com/forums/at...6&d=1389406997

Maybe Arthur can chime in for some more detail

[Tungrus]

Originally Posted by ohdan56

Would one of you be so kind as to explain to me the use/application of a pancake shifter? I am not familiar with this equipment. How does gearbox interact with the pneumatic cylinder? Thanks, I'm learning!

Glad to see this: Thanks, I'm learning!! (emphasis is mine). This is possibly the best trait anyone can have!

[Trent B]

The use of pancake is referring to the geometry of the cylinder as well. As you can see from the attachments posted by geomapguy, the stroke needed to shift is very low, however you may still need a considerable amount of force to shift requiring a larger bore.

Proportionally the cylinder is short and wide, compared to more conventional pneumatics which may have a stroke 10x the bore.

[artdutra04]

Originally Posted by ohdan56

Would one of you be so kind as to explain to me the use/application of a pancake shifter? I am not familiar with this equipment. How does gearbox interact with the pneumatic cylinder? Thanks, I'm learning!

The pancake pneumatic cylinder is a type of pneumatic cylinder that is as compact as possible.

Here is a drawing for a typical 3/4in diameter bore, 1/2in stroke (travel) pneumatic cylinder that is identical to what you can order from Bimba:
http://www.mcmaster.com/#6498k631/=qanv3j

As you can see, even through the stroke is only 1/2in, the overall length of the pneumatic cylinder is 5.03in long when fully retracted. The pancake cylinders in comparison were designed to be as short as possible for a given stroke; if you look at the same PDF I posted earlier a 3/4in bore, 1/2in stroke pancake cylinder is only 1.19in long. For shifting gearboxes there is no operational difference between a typical and pancake pneumatic cylinder, however the pancake cylinder is smaller and lighter.

For both the ball shifter and the dog shifter, the pneumatic cylinder is connected to a shifter shaft coaxially within another gearbox shaft. The smaller inner shaft can move in and out, while the gearbox shaft transmits the torque. For the ball shifter, there are balls in the gearbox shaft that can be pushed outwards via a step in the shifter shaft to engage into a gear and the gearbox shaft at the same time to transmit torque. For the dog shifter, a pin or screw attaches a dog to the coaxial shifter shaft to slide the dog to engage a gear into the gearbox shaft.

[brianbond]

Thank you for that. It really helped!!!