Hi Carbymaster, I am certainly looking at building one but at the moment I'm struggling to get around, even the mower with the float clip in it is still on the bench. Hopefully once I have my hip replaced I can get back to doing things. Have you worked out any of the measurements on the length of the top and bottom frames. I should be able to work them out by drawing it out on the concrete but even that is a bit of an issue at the moment. I guess I could copy motorcycle lift plans and just reduce the size and material. I'm thinking for stability it will need a scissor on both sides and then it all starts to get heavy. I still need to work out what I can use for the channels both sides top and bottom.
Hi NormK, All arms are 50cm in length with 45cm between pivots. The drawing and calculation shown only on one but the actual design has to be two pares of dual scissors. The length of the arm is calculated based on the maximum height of 90cm and maximum angle of 60 degrees. From base to first mid of scissors at Max height is 23cm and possibly car scissors jack can be used to lift the mid up to 23cm high. The total weight of the frames or platform was taken into account on the design to calculate the initial force to lift the scissors at full load of 30kg. You can use a 50x50 or 65x65mm post for the channels where the bearings goes inside the post with side slot. The arms you can use a 50x25mm fence frame or similar.
I think I will see if I can make it out of 50 x 25 tube and see how it handles it. The scissor jack might help and it can be run up and down quickly with a battery drill
I will cut some strips of wood and make up a pattern of one side of the scissor so that I can see how it will operate and then I can work out the amount of travel along the top and bottom rails. This is a motorcycle one which has a height of 870mm and a low of 350mm . It looks like the arms might be about 500mm so at these measurements it will give me an actual lift of 320mm .The 870 deck height is achieved but the base being 350 above the ground. I might make the test arms 600 long to start with and see where that takes me, https://www.ebay.com.au/itm/New-Mot...Jack-Hydraulic-135KG-Stand/202642800904?
I think I will see if I can make it out of 50 x 25 tube and see how it handles it. The scissor jack might help and it can be run up and down quickly with a battery drill
NormK, I recently tried lifting a corner of my car with an 18v cordless drill and scissor jack, and even on low gear, it couldn't do it. Maybe with this load, it could work though.
Great concept Carbymaster, but I don't have the confidence I could construct that myself.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!
I saw the bike lift also a double scissors. Looking on the scaling and based on my calculation at 60 degrees, max height of 87cm and min height of 35cm, with vertical travel of only 52cm, the arm is only 30cm long. When you use 60cm arm with 55cm between pivots, at 50 degrees angle, the vertical travel is 84cm plus minimum height of 10cm-16cm (for castor wheels and base frame), the total height would be 94cm-100cm. Good choice of arm length. You only need the car scissor jack to push by at least 15cm to raise to 1m height.
Ok so I made up a test piece using the 450mm centers and it works fine, it takes 180mm horizontal travel to get it to reach 800mm high which is all I think it needs to be. My only concern is that at that height it may be too narrow and then be a bit unstable.Using 40mm wide strips I can only get it to fold down to 200mm high but I don't see that as an issue because you can lift the front wheels up onto it and then lift the rear wheels on by lifting the handle. I think I will make up one with 600mm centers and see what that looks like.
I wonder if you could put lockable wheels on it so It could be used to load a mower into a vehicle. Thats about the only time I ever notice the weight of a mower. With something like a Victa 24, its a bit of a struggle to get it up into a 4WD ute alone. Here I back the ute into the kerb then load it front wheels up first followed by the rear with a bit of a grunt. Local traffic must wait for me but they do not seem to mind if its not very long.
Seems to me you need a rotisserie style stand in there as well so can easily rotate a mower. Handle would be a problem I suppose but I do most underdeck work with the mower on its side (on the ground of course). Always turn them spark plug up unless there is a sticker which says otherwise.
Hi Jeff I wouldn't attempt to put a 24 on a 4WD ute on my own, pretty easy with 2 people though. . They go onto the trailer easier than a PT because you drop the tailgate put the front wheels on it and then push/lift the rear of it on, very easy. I could/would not attempt to work on a mower on the ground. I made up another test piece with hole centers at 600mm. This achieves the 800mm lift height without it looking unstable. I used 25mm strips as I was thinking that I might be able to get away with using 25mm square tube for the scissor arms. Using the 600mm centers it means the bottom only requires 115mm of travel to lift the table to 800mm. I assume this will require a scissor jack to lift it
Great work. I've never thought you will start working on the scissor lift. I can see you're really determine to build one. The 60cm looks good and it proves the calculations. I think you can get away with 25mm square tube and it would be stable and rigid with cross members between scissors. The car scissor jack can be installed horizontally pushing the bottom largest cross member which takes most of the push. Also I've never thought about the drill the drive the car scissor jack. Just extend it on the side. Good idea.
My main concern at the moment is if the screw jack will be able to push it up from the fully closed position or will it just bend it because it is pushing in too much of a horizontal plane.
What sort of a deck will you have on that? Something that only supports the wheels or the edges of the mower I suppose. Will any mower fir includung a 24? Or will it just take 18-20 inch mowers? You would have to be able to get underneath to undo the blade disc. Neeed to use a rattle gun or the whole lot will come tumbling down. I keep trying to imagine a lifter with a rotisserie included. Difficult but not impossible. Might have to clamp to the front of the mower. Only needs to rotate 90 degrees so handle could stay on.
Assuming Mower = 25kg, Platform = 15kg, Arm Angle = 5 degrees, Gravity = 9.8 m/s
F = (25 + (15/2)) / (Tan 5 x 9.8) F = 38kg
Find a cross member that can withstand a 38kg of horizontal force of the scissor jack in the the middle of let's say 60cm long of cross member. It shouldn't bend.
Jeff Do you mean more of a Lazy Susan idea so that the mower can be rotated around on it. As for getting under the mower to get to the blades etc, I just tip the mower on an angle on the bench and I have a rope hanging down from the roof, I tie that around the handle with the mower at about 45 degrees and I'm good to go. I would not even think about trying to get a 24 up onto the bench, they are not too hard to work on, standing vertically isn't too bad. The ones I have real issues with getting onto the bench to work on are the Honda self propelled. Last one I worked on I lifted up onto the bench with a chain block CarbyMaster, I have plenty of heavy steel here, that is not the problem, it is when it gets to the point where the bottom scissor arm is nearly horizontal, once you start pushing on it it doesn't want to lift. The alternative is to stop it from coming all the way down and then that sort of defeats the purpose, although even if it was 300mm off the ground you could still get the mower up onto it with little effort
On reading a little more of the original posts I see that the reason you are thinking of this idea is that you are in a lot of pain at times and movement is restricted.. I'm sorry to hear that and offer my sincere wishes for a speedy recovery.
I was thinking of something more like a rotisserie. My mate made one for the chassis and the body of an old Chev he was working on. If you get the balance point right you can rotate the chassis with one finger so its easy to weld underneath, and paint etc. I do not think you would need to be so accurate for a mower, they are not that heavy. All I can think of is a solid post in the ground with a frame that goes right round the mower with a couple of sliding attachment points that clamp to the mower frame. This frame would rotate on some type of axle.
Lifting would have to by something sliding up the post maybe pulled by a boat trailer winch.
I wonder if we could adapt a rotating engine stand.
My concern with your idea is that it might be unstable unless the base is very wide, particularly if you are going to lift mowers on their side on it. If it is very wide you will have to step over the base rails when working. I suppose you could just use the scissor lift to raise the mower high enough so you easily push it on to your existing bench. That might work.
Even to change the oil in a Briggs you have to tilt the mower. I usually end up with it right upside down to get a complete drain after sucking the fuel out first and removing the air filter. Its a good idea to drain the tank anyway at service time.
Anyway I can not think of a practical way of building this thing yet,
We had a block and tackle and girder running along 3 mtrs off ground to move products........ in the factory. Worked well after years of two blokes lifting the things off our benches,,,, after too many back problems. Simple block and tackle $43. https://www.ebay.com.au/itm/0-5T-Bl...-Hoist-Crane-Chain-Lifting-Pulley-500KG/ Girder Roller $59 https://www.ebay.com.au/itm/Girder-Trolley-1-Ton-1000kgs-Crane-Push-Type-I-Bar-Beam-Track-Girder-Trolley/392290824312?hash=item5b565af078:g:a8oAAOxy3NBSeyON Don't know how much 3 mtrs of old steel girder...... Those chain pulleys work well, easy lift and just roll along the girder to bench....... There is also a ute tray lifter thet would work pretty well, and can swing an item....... I met a cockie who invented his own with a boat winch and ran the cable through the upright pipe.......... My ramp and bench works for me and I often lay mowers on their sides , tie the down... Beats a sore back for 3 or 4 days. cheers speedy
........................Keep your blades sharp......................
Hi Jeff, Thanks, yes be glad to get this hip problem over and done with, it has got a lot worse since Christmas. Hi Speedy, I have a girder through the garage with a trolley and chainblock on it. million motors have been changed on that over the years. I also have a small electric winch I have never used, I was thinking of having my bench pivot on hinges one end and the other end drop to the floor, push the mower up up the bench, put a block behind it and then winch the table back up. All these ideas spinning around in my head at the moment
The pivoted bench sounds a good idea. It should be be very stable and nothing on the ground to fall over. As Speedy says a ramp would work but you would need enough room which I do not have
