doug72

These thin lift arms would be great for building lattice structures such as crane jibs, towers and bridges Thin "K" & " T" connectors would make for a versitile building system for these type of MOCS. Probably would need a new connector pin. 3/4 - with stop - 1/4 (I think Efferman has one in his 3D parts) Doug

See this link which has images & video of how the wheel was constructed and the ball loading mechanism etc. http://www.eurobrick...howtopic=130443

Grey shock absorber received and the change over and drive units built as per Blakbird instructions. Took a while to get c/o to work correctly but eventually got it figured out. As the unit is quite large it was too big for what I required, so I set out to replicate the change over and dwell functions in a smaller unit. Change over device uses a grey shock absorber but a much smaller trip lever snap over unit. The 56Z turntable replace by a 28Z small turntable with shorter arms to give the same dwell action to the elevator cord driving wheel. The whole unit is built within three stacked 5L x 7L frames for a very rigid structure. Frame 1: Change over lever unit. Frame 2: Reversing unit with clutch gears Frame 3; Output gear unit giving up to four outputs. Drive: M motor driving reversing unit via a worm / 24T gear. Next step is to build an elevator tower and the ball moving cage. The images below show the construction. Size comparison: IMG_3678 by Doug Ridgway, on Flickr IMG_3679 by Doug Ridgway, on Flickr IMG_3680 by Doug Ridgway, on Flickr IMG_3682 by Doug Ridgway, on Flickr IMG_3681 by Doug Ridgway, on Flickr IMG_3683 by Doug Ridgway, on Flickr

Update: Found that over time the change over mechanism built of studded Technic parts tended to get out of sync. due to cams shifting and also to fall apart if any jams occurred. I set out to build a more robust mechanism and would cycle repeatedly without any drift or jamming using studless technic using 5L x 7L frames for a sturder construction. The change over uses the new type change over with Red clutch gears and white sleeve and is moved backwards and forwards using a worm driven crank arm. The C/O shown uses a 24T gear with two 8T gears in order to keep crank arm axle at correct position. If a 40T gear is substituted then the dwell time at each end of trolley travel increases. The drive pulley diameter has to be selected to give correct travel required with a slight over run allowing the elastic drive cord to slip when the trolley end stops are hit. Ball loading can be adjusted to transport between 1 to 4 balls at a time. Side View: IMG_3676 by Doug Ridgway, on Flickr Overhead view: IMG_3677 by Doug Ridgway, on Flickr

You would expect TWO 8T gears to mesh with two white clucth gear but If you zoom in there seems to be an odd (new) RED part meshing with them. It appears to have only one 8T gear ( similar to the 3L worm gear.) Also the axle its on sticks out so might be a sliding axle with red gear alternatively meshing with either clutch gear - possible due to interlocking of the various motions. All will be revealed when the set is released.

Received set no. 21305 MAZE today for Fathers Day. It contains 4 Lego orange balls p/n 6023209. Balls are plain orange without any markings Checked lego on line and they available at £0.66 each in quantities up to 200.

Braided elastic cord is a good solution for trolley travel with just enough friction to move trolley along the arm but cord slips when end stops are reached. Self tensioning and no tangles. See this link which shows how this was acheived - which only requires a drive to the top of the tower. Tower Crane (MOC) with horizontal jib http://www.eurobrick...72#entry2348939 Doug

My trencher machine is on hold at the moment as have used all my buckets on a GBC BWE lift. If I build it it would have a circular bucket wheel not a linear one. Doug72

Courbet, Thanks for the timely advice, saved me stripping down work done so far on the c/o unit. Grey shock absorber arriving next week. Doug

Blakbird, Many thanks for the advice and the excellent instructions. Wiil buy a grey shock with soft spring. Re Driving ring. On page 80 step 17 the part shown appears to be a plain 2L axle connector and the driving ring stays up OK but I will change anyway. Finally got c/o to work OK after I found I had missed putting the two stops in place either side of the Red lever at step 20. Thanks again. Doug

Nice simple idea. I,m going to try and see if this can be adapted to provide a snap action for driving ring change over.

Elevator GBC (HELP) Downloaded the pdf instructions by Blakbird and I am currently building the top part of this module with XL motor and change over unit to incorporate it into my next planned smaller GBC version of this module. On page 77 - step 9 a shock grey absorber is used. I only have Yellow version which seems very hard to compress and requires a lot of force to rotate the shaft with crank & wedge pulleys. Presumable this gives the snap action to the change over unit. Can anyone explain the difference between grey and yellow shocks. Am I correct in using a plain 2L connector in the driving ring instead of using the ribbed type ? Thanks in advance for any help. Doug72

Using instructions download for Sariel’s 4 speed sequential gear box I first built it to see how it functioned and then used it as a starting point to develop a change over device for various planned GBC modules. Two units were developed using the old and new type driving rings contained within 7L x 5L studless frames By using different gear combinations different speeds can be obtained for the reversing motion - for really slow speed another worm reduction stage can be added between the M motor and reversing unit. The two units shown have 24:1 and 40:1 reduction. Minimum possible 8:1 Maximum 1600:1 The output crank is 2L and drive crank for c/o driving ring lever is 3L which gives very little flexing in the structure as it rotates. Connecting rod is 8L centers. Images below should show how these were constructed & the differences between the two units. Top view: Top image using old type driving rings / Bottom showing newer type driving rings IMG_3665 by Doug Ridgway, on Flickr Underside view showing gearing arrangement for old (top) and new(lower) The reversible outputs can be taken from any of the 4 axles. IMG_3666 by Doug Ridgway, on Flickr Side view: showing top worm:24T reduction. A 8T gear is between worm and 3 & 24T gear to keep crank axle at same level. Lower has 40:1 reduction. IMG_3667 by Doug Ridgway, on Flickr Opposite side view IMG_3668 by Doug Ridgway, on Flickr End on view showing crank arms IMG_3669 by Doug Ridgway, on Flickr

Andy, Only expense so far are some extra M motors, rest built from various studded parts I have lying around unsused and from broken down lego models. I enjoy the challenge of getting a GBC to work and devising new solutions to problems. Building these at the moment until the BWE set is released. Doug

Thanks for the comment. Check out this website - http://pv-productions.com and look at Lego Creations page. I brought and downloaded the instructions from this website,which show a GBC built using bricks and studded beams with studless beams for the complex linkage. Various other GBC module instructions are also available. I substitued studless beams for the brick tower structure making it much stronger. See other posting of my self contained Bucket Wheel Lift & Incline trolley lift modules on one base plate. http://www.eurobrick...1 Sorry there are no instructions as I use build design principle and no idea how to use LDD. The 56L x 28L base plates are ideal for self contained GMB modules. Eventually the two base plates will be combined and modules linked into one circut on a 56L x 56L base.

Now replaced the 24:1 worm reduction gearing with plain 40T and 8T gears giving a 25:1 reduction. Now runs much smoother and quieter.

The mechanism framework and moving parts is a copy of PV's design using only studless beams giving a firmer structure. Yes reduction is by a worm driving a 24T gear. Only runs for short periods but agree for long run times a double reduction would be better. Have now got two 40T gears so can be easily changed as per PV's design so might change it back. Worm drives ideal in tight spaces but plenty of room on a GBC normally. It's very hypnotic to watch. The white beads subsituting for Lego Balls can bounce a lot hence the various guards to stop them escaping.

Looking for another GBC to build I downloaded the excellent instructions by Paul Verbeek for building his GBC # 5. This was built as per instructions but as I only had one 40T gear I had to use for the 1st stage reduction a 36/12T gear combination, giving an overall gear reduction of 15:1 instead of 25:1. Many of my studded parts are quite old & worn. When the contraption was run the increased cycle rate caused it to fall apart !! Decided to build a stud-less version and eliminate the double gear reduction which was replaced by a simple 24:1 worm gear unit directly driving the crank arm. Instead of using the ball loading device shown in the instructions I used the same ball loading gate as used on my GBC #1 - Bucket Wheel Lift. Getting the trip lever geometry right took a lot of attempts to perfect ! Ball return run is only temporary until I build a 4th module (vertical lift ?) and link them all together. The only non lego part is the 56L x 28L base plate by Play BLOX from Wilco at £3.50 - approx 1/4 equivelant lego price. See video which is best with sound Off. [m.e.d.i.a.] [/m.e.d.i.a.]Doug

There were times when building my various crane MOC's that a 17L or 19L beam would have solved a problem in installing all the motors, gears and winding drums in a limited space without fouling on the supporting structure. To join beams end to end requires another short beam on one side taking up valuable space or touching rotating parts. An extra 2L or 4L would not impact greatly on the strength of a longer beam. only if a point load were placed at mid point would that occur. To make a 17L beam at requires THREE parts, ie. 7L + 9L beam (or other combination that adds up to 16L) with a 5L beam connecting them on the side which leaves a gap of 1L between ends of the other two beams thus making the overall beam less rigid. Longer beams would make building lattice structures (crane jibs. towers etc.) more easy and would require less parts making them look less bulky. As a boy I played with Meccano and they had girders up to 36" (915mm) long.

The current 15L studless beams can be very restrictive when building large models such as cranes, large trucks etc. 17 / 19 / 21L would be useful and avoid need for joining beams end to end with short studless beams. We have 32L axles so why not longer beams ?

Substitute Lego Balls Recently ordered & received 14mm diam. white acrylic beads from www.etsy.com (craft material website) to replace the glass marbles I was using on my marble run contraption. The ones I got came from a firm in Greece. Tried them but found that with their weight much lower than glass marbles that they behaved much differently often falling off or jamming. I had to modify the loading and unloading mechanisms for the various sections of the marble run. Bucket Wheel: loading gate and collection hopper re-configured. Trip lever adjusted to give correct timing as new balls roll and drop slower than glass marbles. Incline lift: Previous loading gate only allow one ball at a time to enter the lift trolley, changed to 2 per trip but balls tended to back up on the conveyor section. Finally made a loading gate that allows up to 4 balls per trip to load. Ball run slopes also had to be made steeper as the hole though the center of the bead sometimes caused them to stick until struck by next ball that came along. Next challenge to build a scissors lift section.

Works OK in the UK and no fees are payable by the buyer. Sellers pay any PayPal fees. You can also set it so that payment is not taken from your bank a/c by PayPal until the goods are received.

Lego now allow PayPal to purchase parts - just used it to get some new M motors now that they are back in stock.

Looks and works good. What part number are the helix tube sections ?

DMRC - Video Marble Run Contraption complete - after a lot of tweaking now runs fairly smoothly. Bucket Wheel lifts balls up onto the transfer conveyor which then drop down to the loading area for the dog cart. The dog cart pulled up & down the incline and is driven by M motor via a change over mechanism. The c/o mech. is based on the one by Lego GBC with some slight modifications to the c/o rod and cams. At top of incline balls drop on the ball guides and roll back to the start. Currently glass marbles used ( which had to be checked for diameter ) to ensure no jams. Hoping to source some plastic beads to replace them. One thing had to ensure was that the switches on the battery boxes can only be on at one position and block the other way, Had a spectacular desintergration of the bucket wheel when it rotated the wrong way !!!! [m.e.d.i.a.] [/m.e.d.i.a.]