Ideas please for a drop-floor mechanism

[angib]

My thanks to Roly and Cliff for posting about the Trail Feather trailer - I have been thinking about a drop-floor trailer for a while and this thread got me started.

There seem several advantages to a drop-floor trailer, compared to a lifting top:
- no restriction on the shape of the fixed body;
- easier to build a drop-floor than a lifting top;
- (almost) no sealing problems.

I've continued with my previous ideas which are rather different from the Trail Feather's drop floor, as it:
- has hard sides;
- doesn't (quite) rest on ground when down.

There are reasons for these decisions, but they can wait. Here is the design I've got so far.

Looking at the whole drop-floor in the down position with a little bit of (light blue) trailer floor:


Half the drop-floor (so you can see the cross-section), operating:


Looking at the drop-floor, halfway up, from underneath:


The purpose of this message is to ask for suggestions on the method for lifting the drop-floor and for locking it up while towing.

I'm currently thinking of four wires connected to the four corners (four because they should help stop the drop-floor from racking and getting jammed), maybe operated by the smallest boat trailer winch (like Sumner's lifting top), and a couple of locking pins for towing.

But I'm not a lateral thinker, so I would welcome any suggestions anyone can make - though keep the electrically-powered hydraulic ram suggestions to a minimum, eh?

The construction is 1/2" ply sides, 3/4" ply bottom and mostly 1x2 framing - like that, a part-width drop-floor will weigh about 60 pounds, or a full-width drop-floor about 980 pounds.

Andrew

[Wolffarmer]

Angib.

I been thinking about this also. With a drop floor my tear would almost become a standy for me. It would be for my sisters.

I have not figured out a lifting method. Other than brute force. For the sides I would use 3/8 inch ply. My current foot well has 3/8 on the floor and it supports me. 300 lbs But it is not very wide, much wider and I could be standing on the ground.

Wait, just had an epiphany. Forget the drop down box. Just make a trap door. Open it up and just stand on the ground while changing clothes.

That would work for me as I only need it for changing clothes and not frighting the natives.

Much

My foot well is pretty deep as it is. I did make my tear pretty tall so I was able to make the foot well deep. Can sit pretty good inside now. Just would like it easier to change clothes.

[bobhenry]

http://www.virtualplacebo.com/halloween ... piston.htm

Pneumatics ???

I think I just found a redneck hatch lift. Just gotta wait for someone to throw out a couple storm doors.
I have a small emergency compressor that will do the job.

[john]

Springs. I have planned a drop floor myself. A 6" fixed drop and within that a 6" "free" drop for a total of 1'. It would nearly touch the ground when down.


Springs would be mounted parallel to the floor and would be strong enough to lift the floor. If possible I would prefer to mount the springs vertically for simplicity but there may not be enough room for vertical springs to operate.

Slide locks inside the camper would lock it in the up position to allow walking on it when towing.

Stepping on the drop floor would lower it and the same locks could lock it in the down position for camping.

Otherwise it would be essentially the same in terms of sealing as the cartoon above except for being mounted in a fixed drop floor.



My plan so far but new info could easily change it.

[Wolffarmer]

Think outside the box.

Put some iron across the bottom. Then run cables from the front or rear to pulleys, Attach cables to a lever/winch.

[BrwBier]

What about some jack screws and a cordless drill for the power source.

[depatty]

How about using automotive hatch lift struts. One one each corner or maybe just two on opposite sides. To lower the floor stand in it and install the locking pins in the down holes. To raise it get in and remove the pins and get out and let the struts do the work. Depends on how deep the drop section will be. May need to go with an L shaped arm with the strut parallel to the floor, attached to one point, a pivot point at the junction of the legs and the other end doing the raising, possibly with a roller and track similar to that used in a car window mechanism.

Almost wish you hadn't started this thread. I'm to the point with rebuilding the frame for my build of either adding another crosspiece for floor support or leaving it out and doing a drop floor. Now you got me thinking of doing it this way and having a dressing/seating area.

[S. Heisley]

Hi, Andrew:

I can think of a couple very basic things, requiring little skill or knowledge:

Hanging Lift Handles:
Do you remember Grandma's old dresser with the hanging handles? They took up minimal space because they hung down instead of out. I think a simpler version is still made for that very purpose. If you couldn't find them, hang something like a chain between two eye-bolts or whatever works. An indented cubby area, maybe along that inner edge of wood, could house the hanging mechanisms so that they wouldn't be in the way.

A Swing Lift Bar:

You could use a metal bar, similar to what holds up a car's hood, attached to the inside wall of the moveable floor when not in use. When it becomes time to lift the moveable floor, the bar could be unlatched and swung across the width of the lowered floor and be latched with a latching mechanism on the opposite side so that one could use the bar to lift the floor. The latching mechanism could be as simple as one of those hooks used to hold the springs on the old-style garage doors, bolted to the side and brought across the bar.

Holding Brace Bar Ideas:
Take advantage of the lip of the hanging floor to place brace bars between that and the stationary floor. They could even be a type of 'swing' brace that is housed in a cubby area. For this method, a cupping indentation area would be necessary in the stationary floor so that the bar couldn't slip. The indentation area could be reinforced with those metal finger pulls used in cupboards and closets. (There are many sizes of those.)

Another way of doing this would be to have a pocket in the floor where a ‘trap’ door could be opened and the brace brackets could swing up from there and be set or latched in an indented area on the underside of the lip of the lifting floor. Of course, this would mean a little extra reinforcement in that area of the stationary floor but this is quite often done now, to create storage areas; so, it's nothing new to people.

Perhaps one or more of these above ideas will tickle your fancy and rev up that active brain of yours with a good (or better) solution?

[S. Heisley]

It would be difficult to make the drop floor very big as there are cross supports on the chassis frame; but, it could be as big as a small aisle. I don't think that would be very heavy to manually lift.

I like the idea of using scissor jacks and a propelling drill to lift the area from underneath. That would be really good for someone with a bad back or very little strength, provided the drill had good batteries or there was a source of electricity handy or a manual crank could be used. The jacks would also hold the raised floor in place while someone secured it. But, once the floor was lifted and secured, the jacks would have to be removed and stored somewhere. One would need to be able to place the jacks underneath, close to the sides of the trailer, to avoid having to crawl under the trailer. That would probably mean that, for convenience with the use of jacks, the extending floor would need to go nearly the full width of the trailer, from side to side.

[S. Heisley]

Here are two more ideas for holding the raised floor in place:

Locking Bars/Latch Bolts:
The lowered floor could have extra boards on the underside of the lowered floor that latch bolts could be set into from the underside, when the floor is raised.

My names for things may be misleading. To clarify this, a latch bolt is what is sometimes used on fences and can be pulled across and even padlocked in place. It is a bar that goes straight, then curves down and back up and then goes straight again. The 'U' shaped part of the bar slips over a metal ring or appendage that can then have a padlock or other such securing device to prevent the bar from slipping or coming loose from its bolted position. This type of bolt comes in various sizes, some are rather large. A bar bolt is what is often used on a bathroom door.

Resting boards:
Another idea is simply a couple hanging supports placed on each side of the chassis that a couple boards could be slipped through and secured. The raised floor would simply rest on the boards until they were removed, allowing the floor to drop down.

[Miriam C.]

I am going to try to explain this in English without tech words for latches.

What if the drop floor is forced down instead of up and the locking be for that position. The up position being the being the default position. Does that make it easier?

[Sam I am]

I like John's idea of using springs which hold the floor in the up position (also Miriam's idea). I think he is correct in saying there might not be enough room to mount the springs vertically. Perhaps horizontally mounted tension springs could be used with 90 degree pivoting bellcranks. Or could you make leaf springs?

[Donutboy]

How about making a rotating dropped floor? Make the end of the "box" (dropped floor) shaped like

Code: Select all

\     o    /            |         |
 \________/  instead of |_________|

(Note: The angle doesn't have to be THAT shallow.  Drawing with the ASCII characters has its limitations.)


Have a bolt at each end of the dropped floor for it to pivot on (see the "o" in the picture above).Have a couple of pins that you remove to allow it to spin. Spinning it should take a lot less force than lifting it, and the mechanism should be a whole lot less complex.

Down side is that it would be harder to get around in when the floor is in the "up" position. Also, the dropped floor size will be limited by the amount of clearance between the pivot point and the ground.

[grant whipp]

Andrew!

How about a 3-piece telescopic type arrangement where in the closed position you'd have a net depth (that part that hangs below the floor) of 6-7" and in the full-down position something between 15-18"? That way, no part of the footwell would protrude above the floor in the closed position (you could even cover it with a flush "hatch-cover" if you wanted).

I like Miriam's idea of the natural or "at rest" position being closed, and at first I thought of an arrangement of garage-door type springs & cables stretched along the frame rails ... but then I realized it all could be accomplished with camper-door/hatch-lid type gas-shocks (I just haven't figured out the arrangement, yet ... ...).

I'd also ditch the wood-framed idea and only use the wood (3/4" plywood, or perhaps a bit less - depends on the overall size of the footwell) for the floor. I use 18 gauge sheet metal for the footwell "pans" in my trailers, and I think with a couple of well-placed "beads" rolled into the sides & edges, 20 gauge would work fine. The steel would also be a more reliable material to anchor any of the brackets necessary to facilitate the telescoping mechanism.

Food for thought, if nothing else ... ...

As always ...

CHEERS!

Grant

[angib]

Thanks to everyone for the ideas.

I'm thinking through the spring-up idea, which seems like it would really work - I've found rubber cord springs in the McMaster catalogue that would do the job just fine, along with some wire and pulleys. Finding the space to mount them is the next issue.

I think this needs to be a one-person operation from outside the trailer - I can think up all sort of things that involve leaning inside to lift the drop-floor and simultaneously reaching underneath to operate latches - which doesn't fit the one-person limit.

On Grant's point, I think the skills of the builder will influence very much the best way to make a drop-floor. If you have machine or metalworking skills, then a more complex mechanism with fabric sides seems best. But if you're a woodworker (which is me) then all-wood construction with a simple lifting mechanism seems best.

Andrew