How to secure a jockey-wheel to a round horizontal bar?

[dancrane]

My lightweight launching trolley consists of a wooden hull-support braced with a steel bar, and a 40mm aluminium tube from the timber to the bow, including a shallow 'V' to lift the nose. The front 'pulling' end of the trolley is the same 40mm-section cross-bar.

In theory it looks like child's play to bolt-on a jockey-wheel...but all the clamps I've seen, assume attachment will be to a flat surface, such as box-section trailers use.

View attachment 40742

What I need is the standard, circular clamp for the upright of the jockey-wheel column, mated to another circular clamp for attachment to the trolley's horizontal bar.

Obviously it'll need enormous grip - hard to achieve - because every movement of the trolley on rough surfaces will be pushing the wheel backwards from vertical.

I'll need a jockey wheel because hauling-out will require use of a rope purchase, and the nose will otherwise drag along the slipway.

Any ideas how I can secure the jockey-wheel pillar to the round 40mm cross-bar? Thanks.

 

[Rigger Mortice]

Why not bolt together two of the clamps in your photo?

 

[dancrane]

Because, then I'll have clamps for two vertical shafts. I need a vertical/horizontal connector. I've never welded...

 

[prv]

Scaffold clamp? Dunno if the diameters would be right, but maybe you could pad it out with something?

Pete

 

[ningcompoop]

Use a standard jockey-wheel clamp and drill hoizontal bolt holes through the round cross bar, and through-bolt it on. On the other hand, do you need a jockey-wheel - if the boat is well balanced on the trolley, there may just a few kg weight through the nose, so it may slide along the slipway quite easily? (I worked out if I kept the bow of my dinghy about 15cm (that's 6" in old money) back from the snubber, where it you would imagine it should rightly sit, moving the trolley around was sooo much easier!)

John

 

[theoldsalt]

Use a heavy duty forged steel clamp as the one attached to the bar using the jockey wheel hole. It can then be tightened very securely with bolts such that it will not move. The pressed steel clamp in your photo can then be attached to the first with a square adapter plate which will be necessary as one set of fixing holes will be vertical and the other horizontal. You can then attach the jockey wheel in the normal manner. If a lot of rough handling is involved then perhaps both clamps should be heavy duty forged steel clamps - not pressed steel.

 

[Rigger Mortice]

Because, then I'll have clamps for two vertical shafts. I need a vertical/horizontal connector. I've never welded...

Bolt one to a steel plate. Bolt on the other at 90º to the first one. One piece of steel and four holes will do it.

 

[coopec]

Why not bolt together two of the clamps in your photo?

+++

 

[dancrane]

These are all good ideas, thanks for replying. I'm reluctant to drill bolt-holes through the aluminium cross-bar because when the wheel meets an inevitable obstacle, there's a danger that the unbraced column will lever back, bending the tubing. I guess a clamp will allow a bit of movement...

...but for the same reason, the bottom of the jockey-wheel pole will probably want bracing anyway, with a bar or tube from the veed bow-support. I'd prefer a simple castor, bolted below the vee, because I'll only need the jockey wheel for climbing the steep slipway in a straight line...but the pointy vee-tubing won't be easy to attach a four-bolt caster to...

View attachment 40744

...maybe it's a job for a 5" x 5" x 2" timber block, flat on the bottom to take the castor, and shaped on top to fit around the weird rounded point of the 'V'. Nothing's ever easy.

 

[Kelpie]

I just use two trolley wheels on a bit of pipe as an axle, lashed to the underside of the trolley near the front. A bit untidy but I had the bits lying around.

 

[dancrane]

Hmm. There's nothing wrong with the bits & pieces available to fit jockey-wheels, it's only the simple, insubstantial nature of my trolley that makes attachment difficult.

 

[rob2]

Sorry if I've missed this answer whilst quickly skimming through the posts... The jockey wheel clamp on my trailer has square bolts to go round the drawbar, with a couple of nylion rollers as spacers for fitting to the narrower tube of a smaller trailer. Surely, if you get a couple of u-bolts of the correct size to fit your drawbar (40mm) then all you need to do is drill a new hole to suit on the backing plate of the clamp? Of course, you can make up the plate and bolts yourself, with the horizontal spacing to suit your clamp.

Rob.

http://www.ebay.co.uk/itm/Trailer-C...rters_Parts&hash=item3cddf086e0#ht_1444wt_904

 

[dancrane]

Thanks for the thought. I'll go through the options at tedious length, and photograph my solution for displaying here. Not quite sure yet how I'll do it, but I can see it's possible.

 

[TQA]

I think you will finish up welding it. If ALI FIND AN EXPERT WITH THE RIGHT GEAR!

But you could try gluing with epoxy some 80 grade wet and dry to the tube then clamp with u bolts over the w/d. I have had some success with this in a similar situation.

 

[Kelpie]

Assuming that the trolley is part of a combi trailer setup, you will probably need to be able to remove the jockey wheel completely so that the trolley will still fit on the road base.