I am a proud grandfather to our gorgeous and funny granddaughter, Freya. To that end I have been making her some toy's and because angle iron and lumps of metal are not the best materials for a baby to play with, the work has been in wood and some of it can be seen in this blog. Those who follow my efforts, both here and on the main website , will know I am not happiest in working with wood! Indeed I have gone so far in the past to say that I hate wood!
One side effect of this work though is a reduction from hate to "prefer metal" which is a massive move forward. Freya takes full credit for this change. As she grows though I will be able to 'indulge' myself with 'interesting' mechanical projects. It was whilst Freya was visiting us that she saw postman pat on the TV and immediately took interest. Ahah thought I, why not make a ride in Postman Pat type vehicle? Dad could get Freya helping in the garden, filling up the back with garden cuttings and the like.
So during the night (when I have the best time to think) I decided to give it a go. I started a little book for my specification and started writing in such things as safety, power, drive, ease of recharging, seat height and leg room, what lights it should have, indicators? and much more.
Using Alibre CAD (they are a good company, helping me out with urgent problems) I started by combing various dimensions found with ride on cars for sale to the public. I also have started building up various parts such as steering, and axles at the moment and I am really looking forward to making a start. The trouble is that whilst Freya is only 9 months old, I have to plans some flexibility into the design for her to grow! So that's the stage I am at really and this will be a longer timed project (anticipate summer 2012) but I am itching to start!!
Because I intend to have the design done, then build to it (rather than my historical design as I build -served me well in the past!), It is critical to get the scale of the body correct first. The only problem is I need to round up a group of children of various ages to get there sizes (only joking!!!) but fortunately there is data available on the web.
That is why I used part of the morning 'mocking' up the initial design to check for any problems in proportion. The TV Pat's van is very tall compared to length and I think in my initial work I was looking to get the van in the right (not Pat's) shape. I have decided that my first stab resulted in a low a roof profile. I then added the piece of timber above the sheet of plywood, to help gauge proportion. So I will amend the drawings now then use some spare plywood sheeting to check again.
I have purchased some items for the van that will help with the design, those being the wheels (12" diameter and pneumatic) and the motor (12v golf trolley motor). These will help with not only size but in designing the final method of propulsion. Whether I go for two motors (one for each rear wheel) I am not sure. Also whether I go for chain or belt drive is also to be decided.
I intend to involve Justin (Freya's dad) as a 'measuring consultant' for times when come to seating and positioning controls. Both of which must be designed with adjustment to accommodate the years to come.
Since my Son Adam has also got married recently, there is the issue of "well" you have 8 vans to make over the coming years!!!!!!! I have decided that the van will need to be a 'family' van. That way I will only ever need to make 2, one for each of my children's families (not that Vicky or Adam are children any more!). Keep looking back to see progress and if you have any good idea's then please email me.
Because I have not been fit enough (and other distractions) I have not spent very much time turning metal (or wood for that matter!) however because I can use the laptop whilst laid up I have been coming to terms with assembles in Alibre 3D CAD. The more I use this program the more impressed I become. That's not to say I haven't had several headaches with learning how to use the assemblies, especially rotating parts that come in on the wrong plane. However, I am getting there! The only difficulty is I am itching to start fabricating the chassis!
Using the photo import facility and measuring against the image I managed to produce a spreadsheet of dimensions. Really useful facility! Anyway, adding a bit of colour helps differentiate between parts so the picture above is my chassis design to date. I found that importing the pillow block bearings is a great time saver and the best website I have found so far for bolts and various other parts (the grease nipple and pillow blocks came from this site) is 3D content central it will save you a lot of time I am sure.
Well I have at last something to add to the websites! Whilst waiting for some medical treatment I bought a second hand electric motor from a scrapped mobility scooter. I want to incorporate the frame the motor came in (to suit the rear suspension I have designed) and that means making some stub axles as well as making a method to secure the rear wheels to the axle.
I decided to use the keyway cut on the existing axle the motor is secured too and will broach a matching keyway in the stub axle. Onto the new extension (made in stainless steel) a brass bush is fitted to suit the wheels I have bought. Again a keyway between the stub axle and the brass wheel bush (including cutting one in the plastic wheel) should ensure no slippage. A through bolt will secure the wheel, its bush and the stainless steel stub axle to the existing drive shaft. A plastic cover will hide the bolt (I hope to print these in ABS with the 3D printer I have bought)and have either Freya's initials or full name on each.
I do not have a broaching tool but another model engineer, Hugh, also in Brixham, has recently bought a 2 ton arbor press and set of broaches so he very kindly has said I may use his. I am looking for a set of plans for a similar design to that supplied by Hemingways, but being tight don't want to buy the kit.........if you know of a set then please email me.
Here are a few pictures to make more sense of the work done over the last two days, I must say its great to be back into the workshop though...it seems like a lifetime ago since I was last out there. One problem encountered though was a blot on my accident record! I lifted my full face safety mask to check progress and got a couple of fine pieces of brass in my eye! Stupid boy, but a visit to our cottage hospital in Brixham soon had me checked over and some eye cream to administer for 3 days. What a fool!
So I am typing this one eyed.......great to be back though!
when trying out in full scale it was obvious something was wrong! It was not 'stumpy' enough so checking the real vans picture it needed to be completely different. More squashed up in fact....
Basic overhead picture of the chassis. The front (on the right) has the correct angles to allow the steering to turn with the new larger wheels. Design is for 0.75" square steel
Alibre assembly, shows the chassis with the two pillow blocks for the rear axle in place and provisional steering uprights in front. I have yet to decide the final steering layout. Also whether to have suspension or no.....
