- July 24, 2016 at 1:26 pm #2454
Had it ever been considered to use a variable pulley primary drive on the belt drive models, e.g. one of these http://www.hoffcocomet.com/EpiphanyWeb/flexpage.aspx?ID=75 It would be possible to insert a spacer bush into the driver pulley, thus disabling the initial clutch action of these units but keeping the speed variability aspect, This means engine braking would be retained at all times. My reasoning is to allow the tractor under light load to travel faster without having to rev the engine to 3600 rpm. The units can be made ‘torque responsive’ meaning that a load on the blade will over ride the variation out to higher speed that would occur as engine revs increase. Thus the machine may run @ 3.5 mph lightly loaded while the engine revs are limited to say 3000. As load comes on the drive, it varies back to about 1.4 mph @ 2100 engine revs (peak torque). This is similar to the wet torque converter performance on the old IH TD9 . I admit that a variator under manual control would be ideal if possible – the early Bobcat skid steers used this, with the directional clutches downstream, – as in this case. I am in no way connected to Comet, there may be other makers of these pulleys.August 9, 2016 at 6:25 pm #2532
Hi Peter, can you send us the correct link, the url you attached will not open.August 15, 2016 at 9:31 pm #2607
This is a link to Comet’s home page http://www.hoffcocomet.com/EpiphanyWeb/FlexPage.aspx?ID=1 – hope it worksOctober 7, 2017 at 5:35 pm #5084
I realise that the Comet may be far from ideal as it is not under manual control. The simplest of these below have one fixed shaft variable diameter driven pulley & a prime mover that moves in & out on rails to take up belt slack. A secondary drive for a hydraulic pump is possible by mounting a bracket to carry it on the engine’s SAE bolt circle, & having a double fixed dia pulley on the engine. Hoses & wires going to the engine allow movement back & forth of this engine. This would need very little modification to the existing set up. An alternative is the fixed centre drive (again under manual control) is also shown http://www.speedvariablepulley.com/variable-speed-drives.html
You must be logged in to reply to this topic.