Study of an ironing device

[Boby2]

The figure shows a device for ironing, or other finishing operations, a roll of fabric.
The fabric is fed by the braked drum A, guided in the horizontal section by the idle rollers C and D and collected by the motorized drum B. In the horizontal section, the fabric is pressed by the movable steel plate E, of mass 30 kg, against the fixed plate F, also made of steel. The connecting rod H is hinged to the plate E and in a barycentric position and to the frame of the machine M.
• Calculate the crushing load on the fabric for a connecting rod angle of 45° when the machine is in operation.
• Taking into account a load acting on the fabric between the feed drum (braked) and the ironing device T0=100N, calculate the increase in load downstream of the device.
• Make a construction drawing of the Plate (E), Connecting Rod (H), Attachment to the frame group.
Assume the steel-fabric friction coefficient f=0.15
I hope someone can give me a hand.

 

[MintJulep]

In my many years of experience I've never heard the term "barycentric". I had to look it up.

The geometry leads to self-energization, which contributes to both the "crushing load", and if we guess that T0 is tension somewhere, that as well.

I guess that "construction drawing" is somewhere defined in the text in this context.

 

[Boby2]

In my many years of experience I've never heard the term "barycentric". I had to look it up.

The geometry leads to self-energization, which contributes to both the "crushing load", and if we guess that T0 is tension somewhere, that as well.

I guess that "construction drawing" is somewhere defined in the text in this context.

Unfortunately, that's the way the design is: it's a task that requires the construction of machines and as such, one has to make assumptions to solve it.

 

[3DDave]

One can either use a differential equation or use an iterative solution.

The iterative solution is as follows:

The initial guess is that the 30kg mass provides a friction force of 0.15*30*g that is added to the 100N that is required to overcome the feed drum.

When it does this it also provides a down force due to the reaction at M. Being that the angle is 45º the down force due to friction should equal the friction force.

This force is added to that provided by the mass, which increases the friction force.

As long as each increment is smaller, the solution will converge.

For example, if the link H is steeper than about 81.6º then the machine will be self-locking.

 

[Boby2]

this is my solution but, the dimensions 200 and 400 mm are the length and width of the moving plate?

 

[IRstuff]

The symbol T is usually reserved for a tension, and in your own problem statement it's the tension in the fabric, since it's between the feed and the uptake

 

[Boby2]

The symbol T is usually reserved for a tension, and in your own problem statement it's the tension in the fabric, since it's between the feed and the uptake

how is the reasoning valid and is the solution correct?