doug72 Posted November 25, 2015 Posted November 25, 2015 (edited) (WIP/MOC) - Dockside Level Luffing Crane My latest project is to build a Lego replica of a Meccano Super model of a Stothert & Pitt level Luffing Dockside crane which has two unusual features. The hoisting hook is maintained at a constant height when the jib is raised or lowered (luffing) by means of the “Toplis” system. Luffing the jib is NOT done using ropes and pulleys, instead this is done using a crank and a connecting beam to the jib. This type of crane was able to raise and lower the jib very quickly without fear of over luffing. Stothert & Pitt Dockside Crane dockcrane by Doug Ridgway, Meccano super model LLDS-crane by Doug Ridgway, on Flickr “Toplis" Level Luffing system explained here: toplislevelluffing by Doug Ridgway, on Flickr Progress to date:_ Traveling Gantry has a track gauge of 15L, the same as my giant Block Setting Crane. Basic unit built but further improvements are planned. Each gantry leg has two track wheels - wheels are only driven on two legs of the gantry (one on each track rail) which sufficient to move the crane along the track. The wheels are driven by a vertically mounted M motor through the turntable via 3 right angle 1:1 units then to a 8:1 worm drive down each gantry leg with a final 12/20 reduction giving an overall reduction of 13.3:1 for the driven track wheels. re missing wheels:- Waiting on a delivery from Lego for wheels rim narrow 18 X 7 with cross hole (56903) to complete this. IMG_2720 by Doug Ridgway, on Flickr Turntable unit: - This forms the base of the crane machinery house and contains three M motors and their gear boxes, each built as a separate unit & mounted on to the turntable along with a battery box doubling as a counterweight. Space is very tight requiring some innovative but legal construction to ensure everything was well braced. The hoist drum & drive will be located in the tower for the level level luffing system. IMG_2721 by Doug Ridgway, on Flickr Next task will be to figure out the correct geometry to get the Toplis Level luffing of the hook working correctly and the crank arm linkage for raising and lowering the jib. A plain hook will be on the hoist rope and later possible a working grab. Edited November 25, 2015 by Doug72 Quote
JJ2 Posted November 25, 2015 Posted November 25, 2015 Looks promising! I cant wait to see the next update. Quote
2LegoOrNot2Lego... Posted November 25, 2015 Posted November 25, 2015 Great idea to build such a crane. You are doing an excellent job so far! Quote
doug72 Posted November 29, 2015 Author Posted November 29, 2015 More progress : The geometry for luffing the jib after a lot of trial & error finally achieved. Machinery house base narrowed by 2L and lowered by 1L by repositioning the gantry drive gears to prevent slewing gear fouling them. Slewing motor now mounted vertically to give more space for rope hoist unit. Luffing motor changed to a L motor for more power with a double worm reduction of 8:1 then 12:1. Note: 12:1 reduction achieved by using two 12T double bevel gears meshing with the worm gear (see Sariel’s excellent Technic Builders Guide - page 49, Fig. 5-12.) A 20T double gear meshes with one of the 12T gears which in turn turns the two crank arms. Jib arm: this caused a lot of head scratching as the arm has to taper towards the jib head in both directions requiring a compound connection at the jib base. Jib will be better colour co-ordinated once extra grey 15L beams arrive. Still waiting for the Lego wheels for gantry. Next step is to determine the geometry & height for the tower for the “Toplis” level luffing rope system and build the rope hoist drum unit. Two views of progress. IMG_2723 by Doug Ridgway, on Flickr IMG_2722 by Doug Ridgway, on Flickr Quote
doug72 Posted December 1, 2015 Author Posted December 1, 2015 (edited) Worm drive problems !!! Having sorted out the geometry for the luffing rope system I found the drive to the jib cranks was jumping a gear tooth as the jib reached the maximum raised position. Also there is a lot of backlash in the worm drive as cranks went over centre the jib arm jumped to new position taking up backlash in the other direction. Worm gear is a sliding fit on axles meaning use of bushes to keep it in correct contact. So a re-think on how to drive jib arm cranks - eventually used a 6588 gearbox which has an enclosed worm and 24T gear. Thin side plates are required to allow the gear box to be correctly alighned on studless technic beams. Motor had to be raised 1L to accomodate the new drive. Success - jib raises and lowers smoothly at last and as an added bonus now have two beams on on top of the L motor on which to mount the hoisting motor and rope drum. Have ordered some 32166 half worm housings which use 24T gear and have correct pin hole spacing for studless beams. Edited December 1, 2015 by Doug72 Quote
doug72 Posted January 4, 2016 Author Posted January 4, 2016 Progress report:- Hoist motor and gearbox installed . Jib now all one colour and tapers in both planes towards the jib head OK. Geometry for level luffing rope system almost figured out - the hook stays at same height when jib is at max. & min. positions. In between the hook rises in a very shallow hump. Progress on hold at present awaiting the Efferman turntable system as weight of the jib tips the whole rotating cabin forward despite counter balancing with two steel blocks at the rear. The Efferman 3 x 3 x 3 wormgear boxes would have allowed for an easier build of all four motor / drives. Currently building a MOC, using these gearbox units, of the worlds first true mobile crane built in the late 1920,s by Ransome & Rapier, which used a petro/electric system with castor steering and drive. Quote
doug72 Posted January 13, 2016 Author Posted January 13, 2016 (edited) New Efferman turntable support ring and wheel holders received today. Prior to receiving the new parts I modified the travelling under carriage to provide the locations for the eight 3/4 pins needed to locate the 13L turntable support ring. Pins installed for turntable support ring IMG_3005 by Doug Ridgway, on Flickr With the previous arrangement the transmission to the track wheels would have fouled the underside of the new turntable support ring and thus had to be lowered by 2L and re-routed. This had the added bonus of eliminating the two universal couplings with the drive now direct down the legs to the track wheels. Underside of traveling carriage. IMG_3006 by Doug Ridgway, on Flickr Side view of track drive. IMG_3007 by Doug Ridgway, on Flickr Slewing ring installed. IMG_3008 by Doug Ridgway, on Flickr Wheel holders installed IMG_3009 by Doug Ridgway, on Flickr The slewing ring and wheel holders will be coloured later using a grey permanent marker pen. Rotating crane house, motors and gear drives has now to be rebuilt. At the moment undecided to continue this MOC as a level luffing crane or to build a more conventional dockside crane. Edited January 13, 2016 by Doug72 Quote
JohnBS Posted January 19, 2016 Posted January 19, 2016 Link to flickr photos https://flic.kr/s/aHsksW61dt Doug, I'm sure that the link to these photos will not work - my first try at uploading from Flickr and got horribly stuck - but here's hoping. You've probably come across this before but here is a set of pics of a "horse's head" level luffing crane in Lego that I made as a proof of concept rough for TC8 but didn't pursue (too many parts in DBG required). You can see that the jib end stays fairly level throughout its travel, with a slight flick up at the maximum extent and a slight droop when it is at the minimum. The dimensions are fairly critical so you would have ti count studs/holes and enlarge to suit your scale. My information came from Wikipedia "Level luffing crane" which includes a photo and animated diagram I very much like your MOC and hope that this might help. Best wishes, John Quote
doug72 Posted January 19, 2016 Author Posted January 19, 2016 (edited) Link to flickr photos https://flic.kr/s/aHsksW61dt Doug, I'm sure that the link to these photos will not work - John, the link works but to show photos you need to "share them". At first I had some problem showing Flicka images but its quite easy. From Flicka Open the image you want to appear in your post - select the little right pointing arrow at bottom right of the Flicka page. (share photo) Then select BBCode - next select size of image and copy the URL code that is shown. Paste this code into your text for your posting. If posting muliple images I draft the text on my computer along with image codes then copy and paste onto the Forum entry. Hope that makes sense. Re My MOC Almost finished - the hardest part has been getting the level luffing to work smoothly & to find correct locations for the various pivots and pulleys. The hook is at same level at max / min postions of the jib but follows a slight hump in between. I'm sure the original crane did as well. The reason for this design was for very fast luffing of the jib with hook staying resonable level - this along with fast slewing gave quick unloading of cargos from a ship in the days when most loads were not very heavy. My MOC designed to show the mechanics of this type of crane as I always find it hard to do the asthetics to make it look nice ! I will be posting a video soon of it in action. My next crane will probaly be a level luffing crane of the type you describle. Edited January 19, 2016 by Doug72 Quote
doug72 Posted January 20, 2016 Author Posted January 20, 2016 (edited) MOC completed. Click image to see the video. Top works completly re-built after installing the Efferman turntable support and wheel holders. It was quite a tsk to squeeze in four PF motors and their reduction gearboxes and to determine the correct loctaions for pulleys and jib pivot points. Slewing is fast with 96:1 reduction using a worm gearbox with an 8T gear meshing with the turntable 96T gear ring. Luffing a bit jerky due to the rope system friction. MVI_3020 by Doug Ridgway, on Flickr Next MOC will be level luffing crane using the "horse head' system possible using the new Lego rack system. Edited January 20, 2016 by Doug72 Quote
lcvisser Posted January 20, 2016 Posted January 20, 2016 Cool! It looks very nice and I'm impressed that you got it to work in this scale. (I'm not a fan of custom parts, personally, but I guess you tried many solutions before resorting to the 3D printer.) The "level" part seems to work really well, except maybe a bit of height variation near the extreme up-position? Quote
doug72 Posted January 20, 2016 Author Posted January 20, 2016 Ludo, Thanks for your comments. It started out using standard parts but very difficult to squeeze in four built up worm gear boxes hence use of Efferman 3 x 3 x3 worm gearbox. Same with turntable where the topworks wobbled when rotating - new 3D parts eliminated that and made it very stable. Before it needed a heavy counterweight - now only battery box is sufficient. I enjoy build mechanisms to fit space availble. The jib took a while to figure out how to taper it in two directions towards the jib head. Used four LEGO Beam 4 with Ball Cup Socket (15459) to solve that. re Hieght variation: the real crane suffered the same problem at extreme positions. It was the best I could achieve using Lego hole spacings. Quote
JohnBS Posted January 20, 2016 Posted January 20, 2016 MOC completed. Click image to see the video. Top works completly re-built after installing the Efferman turntable support and wheel holders. It was quite a tsk to squeeze in four PF motors and their reduction gearboxes and to determine the correct loctaions for pulleys and jib pivot points. Slewing is fast with 96:1 reduction using a worm gearbox with an 8T gear meshing with the turntable 96T gear ring. Luffing a bit jerky due to the rope system friction. Next MOC will be level luffing crane using the "horse head' system possible using the new Lego rack system. Doug, That looks brilliant and works very well. I have a particular affection for the Toplis system, living within 15 miles of the late Stothert and Pitt's works in Bath. In due course, I look forward to seeing progress on the "horse's head" version - will it rival DevSod's hammer crane ? BTW, next time I will try and load Flickr via my desktop and not with the iPad - then at least the menus may appear as in the tutorial. Congratulations, John Quote
doug72 Posted January 20, 2016 Author Posted January 20, 2016 (edited) John, thanks for the comments. I have a book on the history of Stothert & Pitt which inspired me to build this MOC and also another MOC of an S & P Block Setting crane that used to be on the South Pier at the entrance of the Tyne near where I live. http://www.eurobricks.com/forum/index.php?showtopic=91929 Currently working out dimensions for a "horse head" type crane which will be to a similar scale to run on 15L gauge track. I used to love building cranes from Mecanno when I was a kid. Lego Technic gives the oppotunity to continue crane building. Edited January 20, 2016 by Doug72 Quote
doug72 Posted January 22, 2016 Author Posted January 22, 2016 (edited) Link to flickr photos https://flic.kr/s/aHsksW61dt Doug, You've probably come across this before but here is a set of pics of a "horse's head" level luffing crane in Lego that I made as a proof of concept rough for TC8 but didn't pursue (too many parts in DBG required). You can see that the jib end stays fairly level throughout its travel, with a slight flick up at the maximum extent and a slight droop when it is at the minimum. The dimensions are fairly critical so you would have ti count studs/holes and enlarge to suit your scale. My information came from Wikipedia "Level luffing crane" which includes a photo and animated diagram I very much like your MOC and hope that this might help. Best wishes, John John, I have now made a test rig based on your design and enlarged it so that the main jiib is 45L long. Horse Head Level Luffing Test Rig: Set up in front of computer with the animation running on the screen to allow comparing with the test rig for max and min positions of the main jib. IMG_3023 by Doug Ridgway, on Flickr Diagram of linkage dimensions which best achieved level luffing. The white beams hanging off the horse head represent to hoist rope to determine the hook would stay level throughout. Achieved less than 1/4L deviation throughout full travel. Large linear actuator is used with full 5L travel LLC_links by Doug Ridgway, on Flickr Next crane project is go ! Doug Edited January 22, 2016 by Doug72 Quote
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