ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1] 2  All   Go Down

Author Topic: Friction device for managing wire rope on hand winches  (Read 3040 times)

Frank Koenig

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1318
  • Palo Alto, CA USA
Friction device for managing wire rope on hand winches
« on: September 21, 2018, 01:01:27 PM »

Excuse my morning mania but while posting about tower ideas on "Swaging tools..." it occurred to me that maybe what's needed is a guide through which the rope passes that is near (but not too near) the winch and that applies a controlled amount of friction to keep the rope from springing off the spool and getting all messed up. Perhaps a pair of grooved blocks of UHMW polyethylene, or similar material, with adjustable clamping force.  The guide would have to be far enough from the spool to allow the rope to wonder across the width of the spool as it winds. Or the guide could translate laterally, or in some other way accommodate the layering of the rope.

Might this be useful? Has anyone seen anything like this? I'm inclined to prototype something like this on the Trabes' winches.

--Frank


PS: A single block with a hole bored through it that is intersected by a saw cut -- a split-clamp of friction material.
« Last Edit: September 21, 2018, 01:10:17 PM by Frank Koenig »
Logged
"Nature abhors a vacuum tube." -- John Pierce, Bell Labs

Jay Barracato

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2025
  • Solomons, MD
Re: Friction device for managing wire rope on hand winches
« Reply #1 on: September 21, 2018, 02:58:51 PM »

Excuse my morning mania but while posting about tower ideas on "Swaging tools..." it occurred to me that maybe what's needed is a guide through which the rope passes that is near (but not too near) the winch and that applies a controlled amount of friction to keep the rope from springing off the spool and getting all messed up. Perhaps a pair of grooved blocks of UHMW polyethylene, or similar material, with adjustable clamping force.  The guide would have to be far enough from the spool to allow the rope to wonder across the width of the spool as it winds. Or the guide could translate laterally, or in some other way accommodate the layering of the rope.

Might this be useful? Has anyone seen anything like this? I'm inclined to prototype something like this on the Trabes' winches.

--Frank


PS: A single block with a hole bored through it that is intersected by a saw cut -- a split-clamp of friction material.
I would think more friction would make overrun more likely as that will slow the cable without changing the rotational inertia of the spool.

Sent from my Moto Z (2) using Tapatalk

Logged
Jay Barracato

Frank Koenig

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1318
  • Palo Alto, CA USA
Re: Friction device for managing wire rope on hand winches
« Reply #2 on: September 21, 2018, 04:35:52 PM »

I would think more friction would make overrun more likely as that will slow the cable without changing the rotational inertia of the spool.

Jay, I'm applying friction to the rope, not the spool, much like a rope clutch in boat rigging. This would maintain tension on the rope as it is reeled in, even under no load (allowing an orderly wind), and would be overcome by the weight of the load as it is payed out. It would only be a detriment when paying out rope with no load, as the user will have to pull hard enough to overcome the friction. And indeed, if one keeps cranking the winch out with no pull on the rope a mess will ensue, but this is the case as well without a friction device.

10-20 lbs. of friction would likely be enough to get a small, say 3/16 in., rope to behave, and not be too hard to overcome. The way I foresee using this I won't have to pay out rope with no load very much. On the Trabes towers I leave the rope out when the towers are struck, over-under it, and tie it off with a Velcro.

--Frank
Logged
"Nature abhors a vacuum tube." -- John Pierce, Bell Labs

Scott Holtzman

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 7530
  • Ghost AV - Avon Lake, OH
    • Ghost Audio Visual Systems, LLC
Re: Friction device for managing wire rope on hand winches
« Reply #3 on: September 21, 2018, 04:43:07 PM »

Jay, I'm applying friction to the rope, not the spool, much like a rope clutch in boat rigging. This would maintain tension on the rope as it is reeled in, even under no load (allowing an orderly wind), and would be overcome by the weight of the load as it is payed out. It would only be a detriment when paying out rope with no load, as the user will have to pull hard enough to overcome the friction. And indeed, if one keeps cranking the winch out with no pull on the rope a mess will ensue, but this is the case as well without a friction device.

10-20 lbs. of friction would likely be enough to get a small, say 3/16 in., rope to behave, and not be too hard to overcome. The way I foresee using this I won't have to pay out rope with no load very much. On the Trabes towers I leave the rope out when the towers are struck, over-under it, and tie it off with a Velcro.

--Frank

I have nothing to add but am lurking with great interest.
Logged
Scott AKA "Skyking" Holtzman

Ghost Audio Visual Solutions, LLC
Cleveland OH
www.ghostav.rocks

Jay Barracato

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2025
  • Solomons, MD
Re: Friction device for managing wire rope on hand winches
« Reply #4 on: September 21, 2018, 06:58:15 PM »

Jay, I'm applying friction to the rope, not the spool, much like a rope clutch in boat rigging. This would maintain tension on the rope as it is reeled in, even under no load (allowing an orderly wind), and would be overcome by the weight of the load as it is payed out. It would only be a detriment when paying out rope with no load, as the user will have to pull hard enough to overcome the friction. And indeed, if one keeps cranking the winch out with no pull on the rope a mess will ensue, but this is the case as well without a friction device.

10-20 lbs. of friction would likely be enough to get a small, say 3/16 in., rope to behave, and not be too hard to overcome. The way I foresee using this I won't have to pay out rope with no load very much. On the Trabes towers I leave the rope out when the towers are struck, over-under it, and tie it off with a Velcro.

--Frank
Frank I was talking about applying friction to the rope. On all my boats with hand winches, the most common overrun was when there was tension on the rope that was suddenly released when the spool could freely spin, like pulling on the cable and then stopping.

I was thinking by apply friction to the spool you can control both the spool and the rope. By applying to the rope all you can control is the rope. Once the spool develops some inertia, nothing will stop it.

Most friction clutches on boats I have seen lead to a friction drum on the winch where the line does not stay on the drum and releasing the tension in the rope releases the tension on the drum holding the rope in place.

Sent from my Moto Z (2) using Tapatalk
« Last Edit: September 21, 2018, 07:01:07 PM by Jay Barracato »
Logged
Jay Barracato

Scott Holtzman

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 7530
  • Ghost AV - Avon Lake, OH
    • Ghost Audio Visual Systems, LLC
Re: Friction device for managing wire rope on hand winches
« Reply #5 on: September 21, 2018, 07:23:58 PM »

Frank I was talking about applying friction to the rope. On all my boats with hand winches, the most common overrun was when there was tension on the rope that was suddenly released when the spool could freely spin, like pulling on the cable and then stopping.

I was thinking by apply friction to the spool you can control both the spool and the rope. By applying to the rope all you can control is the rope. Once the spool develops some inertia, nothing will stop it.

Most friction clutches on boats I have seen lead to a friction drum on the winch where the line does not stay on the drum and releasing the tension in the rope releases the tension on the drum holding the rope in place.

Sent from my Moto Z (2) using Tapatalk

It's manual but wouldn't a simple cam cleat do what you want (I must be missing something).
Logged
Scott AKA "Skyking" Holtzman

Ghost Audio Visual Solutions, LLC
Cleveland OH
www.ghostav.rocks

Jay Barracato

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2025
  • Solomons, MD
Re: Friction device for managing wire rope on hand winches
« Reply #6 on: September 21, 2018, 07:27:36 PM »

It's manual but wouldn't a simple cam cleat do what you want (I must be missing something).
If I am understanding the application, it will need a device capable of extending the length of the cable under load. Only a few of the very best powered boat winches do that. The rest basically free spool which creates the overrun situation.

Sent from my Moto Z (2) using Tapatalk

Logged
Jay Barracato

Frank Koenig

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1318
  • Palo Alto, CA USA
Re: Friction device for managing wire rope on hand winches
« Reply #7 on: September 21, 2018, 07:27:58 PM »

Frank I was talking about applying friction to the rope. On all my boats with hand winches, the most common overrun was when there was tension on the rope that was suddenly released when the spool could freely spin, like pulling on the cable and then stopping.

Yes, I see what you're saying. The problem I'm looking at is different. It's that the wire rope is a springy rod that wants to be straight and unless tension is maintained it will unwind itself from the spool and turn into a tangled mess. When you want to start winding it in you need start by paying it out most of the way, arrange the few remaining turns in an orderly fashion, and then maintain tension with your (gloved?) hand as you wind it in until the speaker comes off the ground and supplies the tension. This is what drives me nuts and makes me think about synthetic webbing or even rope which is essentially limp and doesn't fight back. Webbing has the added advantage that it forms a pure vortex on the spool and doesn't wedge and skip when the layer gets to the flange of the spool and has to reverse direction and start a new layer. But if I have to use wire rope, I want the hardware to make it easy.

The spool spinning on its own has never been a problem for me. Automatic brake winches keep the spool fixed unless you actively crank in the unwind direction.

I'm also aware that there are numerous types of wire rope available for winches. Maybe one of the "super flexible" styles is easier to handle, perhaps at a slight cost in durability. The stuff they use for light aircraft control cables is not too bad, just kinda expensive.

--Frank
Logged
"Nature abhors a vacuum tube." -- John Pierce, Bell Labs

Frank Koenig

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1318
  • Palo Alto, CA USA
Re: Friction device for managing wire rope on hand winches
« Reply #8 on: September 21, 2018, 07:37:52 PM »

It's manual but wouldn't a simple cam cleat do what you want (I must be missing something).

Scott, a cam cleat comes close. It needs to work with wire rope, and needs to maintain controlled tension as you wind in before the speaker leaves the ground. My intuition says a fixed friction device might just do the trick. I'll report after I've actually tried something. Might be a while. Signing off now. Have a great (productive) weekend all. -F
Logged
"Nature abhors a vacuum tube." -- John Pierce, Bell Labs

Mark Cadwallader

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1338
  • Helena, Montana USA
Re: Friction device for managing wire rope on hand winches
« Reply #9 on: September 21, 2018, 09:57:15 PM »

Using the UHMW block with a sawed split, you could use an over-center adjustable clamp (similar to those used on stage wagons as a brake, or for clamping parts in a jig) to apply and release tension on the wire rope via the UHMW block.  The locking brake on the fiber rope on a theater fly system is another way to visualize the mechanism.  That would allow a free running outrun, but tension while spooling in.
Logged
"Good tools are expensive, but cheap tools are damned expensive."

ProSoundWeb Community

Re: Friction device for managing wire rope on hand winches
« Reply #9 on: September 21, 2018, 09:57:15 PM »


Pages: [1] 2  All   Go Up
 



Site Hosted By Ashdown Technologies, Inc.

Page created in 0.034 seconds with 21 queries.