cable operated dump trailer

[robs660]

Working on similar What size winch are you going to use?

 

[robs660]

Working on a similar trailer. What size winch are you going to use?

 

[easygo]

Army Grunt,

It is good to see that you found a good service dog. He/she should be a good friend for years. Hopefully you will have a productive time while still there and learning about each other.

Just now saw this post.
So say a 1000lb trailer with a 3000lb load would need 14*4000=56000lbs of force just to get the scissor started. Because as stated, when starting out, most of the load is not trying to lift, rather pull straight forward.

I was thinking along the same line since Army Grunt first posted pictures of the build but I thought the 3:4 block and tackle might be able to handle it. I had no idea of the actual numbers involved.

I have been thinking of building something similar but using an 1800lbs boat winch. However I thought I would connect the cable to the scissor mechanism in the way shown in my Charlie Brown sketch. I thought of putting a pulley or something like that on the front edge of the dump box so the first 12-16" of the pull is almost straight up from having the winch mounted on a post. I was going to use 2:1 block and tackle. Any thoughts?

 

[LD1]

Army Grunt,

It is good to see that you found a good service dog. He/she should be a good friend for years. Hopefully you will have a productive time while still there and learning about each other.



I was thinking along the same line since Army Grunt first posted pictures of the build but I thought the 3:4 block and tackle might be able to handle it. I had no idea of the actual numbers involved.

I have been thinking of building something similar but using an 1800lbs boat winch. However I thought I would connect the cable to the scissor mechanism in the way shown in my Charlie Brown sketch. I thought of putting a pulley or something like that on the front edge of the dump box so the first 12-16" of the pull is almost straight up from having the winch mounted on a post. I was going to use 2:1 block and tackle. Any thoughts?

That would be a lot better than a direct hook to the scissor and pulling in a straight line. I Acutally like that Idea a lot. It will help start the dump and open the scissors and then a much better angle is achieved before the scissors have to do all the work.

And if you plan on using a hand crank boat winch, you wont have to bend over as far to crank.

No real good way to figure the capacities without some measures though. You have to account for the measurments of the scissor mechanism itself, How long the cable is between the winch and scissor, measurments of where the contact point on the nose of the trailer is in relation to the scissor and winch, the angles of the line across that pulley, etc. Lots of variables. But that method will definatally take much less force than the previous mentioned idea.

 

[Army grunt]

easygo,when I first started planning this system the winch on a post was my first setup, my thinking was the cable would go around a pulley mounted on the front this would get the "start-dead pull".Than my Buddie said he would design a 3to2 block an tackle using 3" wheels. an we could power it with one of those inexpensive 12 volt winches from northern tool($50.00)So that's where we are at, the sizzors are not closed, they are at 15 degrease apart from start.It will be a few weeks till i get home to do more on it Ill post update then. later
Army Grunt

 

[LD1]

easygo,when I first started planning this system the winch on a post was my first setup, my thinking was the cable would go around a pulley mounted on the front this would get the "start-dead pull".Than my Buddie said he would design a 3to2 block an tackle using 3" wheels. an we could power it with one of those inexpensive 12 volt winches from northern tool($50.00)So that's where we are at, the sizzors are not closed, they are at 15 degrease apart from start.It will be a few weeks till i get home to do more on it Ill post update then. later
Army Grunt

So are you going to use the pully in the front to start the lift?? If so, I think you are going to need it.

I would still need to know the length of the scissor arms to accuratly calculate it, but assuming ~16" arm length and with the 15 degree open, roughly 13x more force is needed in a straight pull. So if you are using a 3000lb winch, (Not sure on the block and tackle but is a 3 to 2 a 5x's increase in pull??) if so, you would have 15000lbs avaliable. Divide that by 13 and you are looking at an upward dump force of only 1150lbs without the pully in the front of the trailer to start. If the scissor arms are shorter, this would be a little more, it the scissor arms are longer than 16", it woudl be even less force.

 

[Army grunt]

Time will tell.
Army Grunt

 

[easygo]

So are you going to use the pully in the front to start the lift?? If so, I think you are going to need it.

I would still need to know the length of the scissor arms to accuratly calculate it, but assuming ~16" arm length and with the 15 degree open, roughly 13x more force is needed in a straight pull. So if you are using a 3000lb winch, (Not sure on the block and tackle but is a 3 to 2 a 5x's increase in pull??) if so, you would have 15000lbs avaliable. Divide that by 13 and you are looking at an upward dump force of only 1150lbs without the pully in the front of the trailer to start. If the scissor arms are shorter, this would be a little more, it the scissor arms are longer than 16", it woudl be even less force.

Woohaa. I'm learning here big time. Thank you. :thumbsup:
I guess the shorter the scissors' arms the more power they produce. But also shorter arms would force the scissors back towards the aft hinges in order to achieve the same degree of lift thus increasing the power needed for said lift. :confused2: How can we win this? There is no arguing with math so something else have to give.
A former teacher of mine used to say: "Nothing is for ever except for math or a large boulder. But math will probably outlive any stone."

I can't wait for ArmyGrunt to get home and continue with his project.

 

[LD1]

Woohaa. I'm learning here big time. Thank you. :thumbsup:
I guess the shorter the scissors' arms the more power they produce. But also shorter arms would force the scissors back towards the aft hinges in order to achieve the same degree of lift thus increasing the power needed for said lift. :confused2: How can we win this? There is no arguing with math so something else have to give.
A former teacher of mine used to say: "Nothing is for ever except for math or a large boulder. But math will probably outlive any stone."

I can't wait for ArmyGrunt to get home and continue with his project.

The reason the shorter arms will give more power is because it isn't trying to lift the dump as far as fast.

What I mean by this is (These arent actual numbers, but just an example.) Say the arms are 15" long with said angle. If the winch pulls say 1", this will force the scissors open a given amount. It the same angles were used but said arms are longer, it is trying to open FARTHER with that same 1" of winch travel. If the arms are shorter, and the same angle used, The scissors will open less with that same 1" of winch line pull. So obviously it will be harder to lift a farther amoung with the same force applied for that 1".

The downcall is that shorter arms will give less overall dump angle.

I think the only way to win is with the pully at the front.

Just as it is getting to the point where it will stop helping the scissor, the scissor is already open far enough to not require a great deal of force to finish the job.

 

[6thgpSF]

ArmyGrunt,looks like a nice job so far.Is that saw mill yours?On a side note,I see you are a Nam VET.Welcome home.173Abn/VN here. russ

 

[Army grunt]

Yes I built the saw mill last year with the welder the VA. gave me under the "ILP"program(offered to unemployable diss. vets.
Yes on nam "A"2/12 4th Id. 66-67 Infantry Sq. Leader. you were 173 what year?Flew into Operation Junction city in a huie the same day the 173 jumped.(Feb.22-67)We pissed in the same places. Welcome home to you also "Brother"
Army Grunt
sight for my mill build.
Home Built Bandsaw Bandmill - Build your own Bandsaw Sawmill - reserved for falcon

 

[Taylortractornut]

Army Grunt thats a good looking trailer. When I was a kid my neighbor and friend an old man that had a retired construction company asked if I wanted to learn how use a winchtruck.

Their old Macks a Fisrt year R model Mak and a 50s Modle B81 both had 60 ton winches on them. He knew I could drive the 2 stickMacks and we went to the farm on the back roads. After pulling the machine out I asked him about why all his trucks had winches infront of the 5th wheels. He told me that hed show me. I went back to his place and he showed me 2 remaining dump trailers they had. Hey were 25 yard semi dumps. THey were cable dumped.

One had a scissor like yours with the block sheaves running on bushings on the scissors pivot pins. He other the frame was like a modern hybrid trailer dmp with radius arms that the 5th wheel kingpin mounted on. It was hinged i nthe center ofthe trailer. There was a cable that ran through the center of the rig to the fron tandem on the trailer. When you dumped you just wound the cables and it pulled the trailer up to dump. He said both trailers worked pretty well in their day.

 

[Army grunt]

That brings back a memory that has been gone for many years, my cus. taught me to drive a 57 Mack(b-81)with a 20 speed quadraplex transmission. In there gravel bank was a dump trailed that was cable operated, seems to me it had a scissor that let the back wheels get pulled forward with the body raising. I gess this proved to be unstable , because it was crushed on one side.

 

[Taylortractornut]

AG I dont think the Hybrid trailers that are used now with the bogies that stay on the ground didnt get popular here till the 90's. I remember watching dad spread sand road topping on road jobs for base when I was a kid. THe drivers had to be careful when dumping trailers because one axle would come up and the got tippy. Dad always had a special technique for fixing them landings . My neighbor that had the cable dump had a one made into a water wagon.

I miss seeing the old B81 a scrapper bought it for a loading truck.

 

[Army grunt]

Here is a pdf file with the block&tackel my friend designed for my trailer
Army Grunt

 

[easygo]

That looks really good, you have a good friend.
So. I assume that the shorter piece with the two pullies is going to be on the front side of the dump box and the three pullies will be on the center hinge of the scissors?
Are you going to build the hole rig or you are going to have a shop do that?

 

[Army grunt]

He will have it cut on a plasma cutter an ill weld it up an he will power coat it for me
Army Grunt

 

[Army grunt]

As promised, Here are a few shots of the plasma cut an assembly of the block& tackle.
Army grunt

 

[easygo]

It looks much nicer made into steel plates :thumbsup: then it was in the drawings. I'm beyond jealous and envious and all :drool:. When do you plan on mounting it on the trailer? Are going to bolt it or weld it?

 

[evo803]

Great looking project !

Those are incredibly clean and accurate cuts for a plasma cutter . They almost look like they were cut on a flowjet . What type of plasma cutter and table is he using ? I am curious aboutwhat brand and model plasma he used.