Hi,
With the workshop and garage out of bounds due to dire weather I decided to stop moaning and occupy myself.
I'm still very much a novice at CAD but I am making steady progress and over the last couple of days I've been refining my pulley clutch drawing in post #55.
After spending many hours and failing dismally to get the belt to slip I'm now trying a totally different approach as I like to experiment. I've browsed the web and looked at many variable speed clutches but haven't found one to suit my application; I'm not bothered about the clutch providing variable speed as I merely want it to drive/not drive but in the no drive mode I was worried about the "V" belt grabbing and possibly causing me injury whilst I worked at the lathe? It would be highly dangerous for a 1.5HP motor to suddenly apply power so I've been awake at night thinking about the problems involved; I come up with my best ideas in the middle of the night.
Jubilee prototype clutch.
This clutch has grabbed my interest and I'm now like a dog with a bone unable to settle until I sort it out. The drawing above is now updated and hopefully the clutch once made will work as expected? This clutch looks quite bulky but in fact the overall size is only around 75mm diameter and 50mm long.
The material is cast iron and I have suitable blank in stock. The bearings are standard deep groove types readily and cheaply available from "Simply bearings" or cheaper through eBay.
One half of the pulley is securely attached to the motor shaft being keyed and a grub screw will be added making it fixed. The other half is arranged to slide allowing the two halves to open and close. In the closed position the belt will drive arranged so that the top of the belt aligns with the outer pulley diameter.
In order to ensure no drive can take place in the "no drive" position I've incorporated a bearing between both halves of the pulley; as the pulley is opened the belt will be released but my fear was that the belt could still operate as a flat belt if allowed to simply move to the center boss? In order to prevent the belt driving it will ride the bearing ; now lets see if it will drive? I've not seen this tried so can only give it a go but hopefully my theory will be proved correct; the sides of the belt cannot drive because the wedging effect will be lost and the bearing won't afford any drive either; a neat idea but only if it works.
A lot of consideration went into choosing the bearing sizes; the belt bearing especially; rather than having the belt flapping around in no drive mode only limited amount of slack is allowed; enough to release belt tension but still allowing the belt to be very quickly engaged with the pulley; this arrangement also simplifies clutch activation as little movement will be needed. The belt is shown riding the bearing in "no drive" mode.
Two keys are added; one locates the clutch to the motor shaft the other key ensures both halve of the pulley rotate together. Collars and circlips (snap rings) are used wherever possible for simplicity.
To operate the clutch a simple lever coupled to rod or cable linkage will be attached; pulling the lever will apply pressure to the spring in turn applying pressure to the thrust bearing; the outer half of the thrust bearing is arranged to rotate it being secured into the end of the sliding half of the clutch; this will force the two pulley halves together; in order to separate the two pulley halves it will be seen pressure is applied to the other side of the thrust bearing. The lever will be supplied with an "indent" this being either ball bearing or plunger but whichever is chosen it will be spring loaded.
So far I've failed to get the belt to slip and once I can get into the garage in comfort I'll spend a lot of time playing around with this project which I'm finding most interesting. At the moment this is only an idea but I hope to turn the idea into a working clutch.
It's most frustrating that when I want to be tinkering around on my projects in the garage I'm shoveling snow and blasting snow from the car using a pressure washer before I can put the car away. Never mind I can laugh at a huge joke shortly; we put our clocks forward and call it BRITISH SUMMER TIME?
In the meantime I'm enjoying playing around with EMS CAD; it's amazing how much time converting my clutch idea into a drawing has so far taken but it's better than being idle.
Kind regards, Col.
With the workshop and garage out of bounds due to dire weather I decided to stop moaning and occupy myself.
I'm still very much a novice at CAD but I am making steady progress and over the last couple of days I've been refining my pulley clutch drawing in post #55.
After spending many hours and failing dismally to get the belt to slip I'm now trying a totally different approach as I like to experiment. I've browsed the web and looked at many variable speed clutches but haven't found one to suit my application; I'm not bothered about the clutch providing variable speed as I merely want it to drive/not drive but in the no drive mode I was worried about the "V" belt grabbing and possibly causing me injury whilst I worked at the lathe? It would be highly dangerous for a 1.5HP motor to suddenly apply power so I've been awake at night thinking about the problems involved; I come up with my best ideas in the middle of the night.
Jubilee prototype clutch.
This clutch has grabbed my interest and I'm now like a dog with a bone unable to settle until I sort it out. The drawing above is now updated and hopefully the clutch once made will work as expected? This clutch looks quite bulky but in fact the overall size is only around 75mm diameter and 50mm long.
The material is cast iron and I have suitable blank in stock. The bearings are standard deep groove types readily and cheaply available from "Simply bearings" or cheaper through eBay.
One half of the pulley is securely attached to the motor shaft being keyed and a grub screw will be added making it fixed. The other half is arranged to slide allowing the two halves to open and close. In the closed position the belt will drive arranged so that the top of the belt aligns with the outer pulley diameter.
In order to ensure no drive can take place in the "no drive" position I've incorporated a bearing between both halves of the pulley; as the pulley is opened the belt will be released but my fear was that the belt could still operate as a flat belt if allowed to simply move to the center boss? In order to prevent the belt driving it will ride the bearing ; now lets see if it will drive? I've not seen this tried so can only give it a go but hopefully my theory will be proved correct; the sides of the belt cannot drive because the wedging effect will be lost and the bearing won't afford any drive either; a neat idea but only if it works.
A lot of consideration went into choosing the bearing sizes; the belt bearing especially; rather than having the belt flapping around in no drive mode only limited amount of slack is allowed; enough to release belt tension but still allowing the belt to be very quickly engaged with the pulley; this arrangement also simplifies clutch activation as little movement will be needed. The belt is shown riding the bearing in "no drive" mode.
Two keys are added; one locates the clutch to the motor shaft the other key ensures both halve of the pulley rotate together. Collars and circlips (snap rings) are used wherever possible for simplicity.
To operate the clutch a simple lever coupled to rod or cable linkage will be attached; pulling the lever will apply pressure to the spring in turn applying pressure to the thrust bearing; the outer half of the thrust bearing is arranged to rotate it being secured into the end of the sliding half of the clutch; this will force the two pulley halves together; in order to separate the two pulley halves it will be seen pressure is applied to the other side of the thrust bearing. The lever will be supplied with an "indent" this being either ball bearing or plunger but whichever is chosen it will be spring loaded.
So far I've failed to get the belt to slip and once I can get into the garage in comfort I'll spend a lot of time playing around with this project which I'm finding most interesting. At the moment this is only an idea but I hope to turn the idea into a working clutch.
It's most frustrating that when I want to be tinkering around on my projects in the garage I'm shoveling snow and blasting snow from the car using a pressure washer before I can put the car away. Never mind I can laugh at a huge joke shortly; we put our clocks forward and call it BRITISH SUMMER TIME?
In the meantime I'm enjoying playing around with EMS CAD; it's amazing how much time converting my clutch idea into a drawing has so far taken but it's better than being idle.
Kind regards, Col.
Happiness is a wreck of a cabinet to restore.
