Home |
Search |
Today's Posts |
|
Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. |
#2
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
Tom Gardner wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. (...) Are you converting from linear to rotary to linear motion? How about just an overrruning clutch and pinch roller mounted on the end of your air cylinder shaft? Less mass. Fewer parts. Cheaper. --Winston |
#3
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Jun 25, 10:37*pm, "Tom Gardner"
wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. *I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. *No, I won't do it with a servo! *I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. *This seems simple and cheap. *In fact, it's so simple it would seem that it should be an off-the-shelf item! *I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. *The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. *The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. They make pneumatic rotary actuators to do exactly what you want, turn a shaft through a partial revolution and back. Kind of like a super- sized version of the old vacuum windshield wiper motor, uses a vane in a chamber driven by pressure, not vacuum. Might explain why you don't see a geared actuator like you describe. Unless you've got a lot of scrap parts laying around, might be the cheaper way to go! Stan |
#4
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
|
#5
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
For only about 90 degrees of motion you don't need the rack. just use the
crank shaft - connecting rod rod type idea. That is, an air cylinder connected to a shaft with a lever arm. A short lever arm makes for very fast motion, less torque. Karl |
#6
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
Tom Gardner wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. Just search "rotary actuator" on mcmaster.com. |
#7
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner"
wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? I've seen a mechanism like that; my friend Jim invented it to swing the head on a die cutting machine in order to nest the cuts and save material. The guy who invented the rack-type rotary actuator invented it before him. Jim had cam followers supporting the rack where it meshed with the gear. The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. 100ms is pretty fast for an air cylinder which, in this setup, will probably never stop accelerating 'til it hits the endstop . Make sure you install bumpers or hydraulic shocks (Ace, Enidine) at the ends of the stroke. Presumably there's enough friction in the wire feed to prevent excessive overrun when the gear slams to a stop. -- Ned Simmons |
#8
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
"Winston" wrote in message news:mnF8k.42$4J.20@trnddc05... Tom Gardner wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. (...) Are you converting from linear to rotary to linear motion? How about just an overrruning clutch and pinch roller mounted on the end of your air cylinder shaft? Less mass. Fewer parts. Cheaper. --Winston You have amazing vision, that's exactly what I want to replace, it's not tolerant of hard/soft/dry/oily wire. |
#9
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
|
#10
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
"Ned Simmons" wrote in message ... On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner" wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? I've seen a mechanism like that; my friend Jim invented it to swing the head on a die cutting machine in order to nest the cuts and save material. The guy who invented the rack-type rotary actuator invented it before him. Jim had cam followers supporting the rack where it meshed with the gear. The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. 100ms is pretty fast for an air cylinder which, in this setup, will probably never stop accelerating 'til it hits the endstop . Make sure you install bumpers or hydraulic shocks (Ace, Enidine) at the ends of the stroke. Presumably there's enough friction in the wire feed to prevent excessive overrun when the gear slams to a stop. -- Ned Simmons We currently use a rather large urethane bumpers and they get the crap beat out of them even though the striker is 1" in diameter. |
#11
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Thu, 26 Jun 2008 11:14:33 -0400, "Tom Gardner"
wrote: We currently use a rather large urethane bumpers and they get the crap beat out of them even though the striker is 1" in diameter. Have you seen the Ace Tubus bumpers? I've used a few and they seem to work better than plain urethane bumpers, though I haven't tried them in an app where they get really beat on. McMaster carries a limited selection. http://www.acecontrols.com/PDF/TUBUS...log%200906.pdf -- Ned Simmons |
#12
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Jun 26, 11:14 am, "Tom Gardner"
wrote: "Ned Simmons" wrote in message ... On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner" wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? I've seen a mechanism like that; my friend Jim invented it to swing the head on a die cutting machine in order to nest the cuts and save material. The guy who invented the rack-type rotary actuator invented it before him. Jim had cam followers supporting the rack where it meshed with the gear. The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. 100ms is pretty fast for an air cylinder which, in this setup, will probably never stop accelerating 'til it hits the endstop . Make sure you install bumpers or hydraulic shocks (Ace, Enidine) at the ends of the stroke. Presumably there's enough friction in the wire feed to prevent excessive overrun when the gear slams to a stop. -- Ned Simmons We currently use a rather large urethane bumpers and they get the crap beat out of them even though the striker is 1" in diameter. Sounds like a need for a valve that will give a burst to get the mechanism moving, let it coast most of the way (or continue feeding air somewhat more slowly than full on), then once it hits the stop give full pressure to hold it against the stop. Maybe use a couple of valves actuated off the moving parts. Dave |
#13
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner"
wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. =========== Sounds like another fun project. Only problem I see is that most off the shelf rack stock is square, and a round rack will have less tooth contact area which may not be a concern if the loading is light, unless the rack is cut on a flat of the shaft. Can you turn the ends of a square rack round and put some round extensions on the ends to run in the linear bearings? Cutting a flat rack on a round shaft should be no problem, but as the teeth on a rack are straight, it would appear that full teeth all the way around the shaft could be easily cut on a lathe with something like an Acme thread bit [14-1/2 PA] possibly with rounded corners for fatigue resistance. Depth of a 1 mm module / 25 DP tooth is about 0.10 inch. Will 0.30 inch carry the load? Assuming a 4 inch PD, 3 inches is 85 degrees and 4 inches is 115 degrees. Another thought is to use a worm gear setup but stroke the worm back and forth rather than rotating it. IIRC most worms are acme threads with a DP thread spacing, and this would give you an single envelopment setup for better contact and longer life. A 1/2 dia round rack gear indicates a fine DP gear, possible like a 1MM module [20 degree PA] / 24 DP gear. For examples see http://americanprecision.thomasnet.c...375fw?&seo=110 http://www.qtcgears.com/RFQ/default....rs/KHK046.html Let the group know how you make out. Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end? Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625). |
#15
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
F. George McDuffee fired this volley
in : On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner" wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? Tom, we have an almost identical device feeding time fuse for cutting. The assembly consists of a one-way drum clutch inside the feed tire, moved through a portion of a revolution by a crank rod on the clutch whose outer end is moved an air cylinder. It moves the fuse from 1/2" to 4.10 inches per stroke, and has nearly zero backlash (for accuracy). I think that setup is simpler yet than what you described, and does exactly the same function -- precisely and repeatedly for years without any maintenance. LLoyd |
#16
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
"Gunner" wrote in message ... On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner" wrote: "Gunner" wrote in message . .. On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote: On Jun 25, 10:37 pm, "Tom Gardner" wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. They make pneumatic rotary actuators to do exactly what you want, turn a shaft through a partial revolution and back. Kind of like a super- sized version of the old vacuum windshield wiper motor, uses a vane in a chamber driven by pressure, not vacuum. Might explain why you don't see a geared actuator like you describe. Unless you've got a lot of scrap parts laying around, might be the cheaper way to go! Stan I thought I sent one of those to Tom already? Gunner I didn't see it, I'd be interested in purchasing one if you still have one! Geeze....email me your freight info again..Since Ive been on a kick to trash stuff...Im down to the pneumatics section in the stacks O stuff Tell you what...Ill email you pictures of the stuff..and if you want..Ill ship you the entire lot. Might be several thousand pounds of cylinders, etc etc. All NOS, ablit some has some surface rust in non critcal places Free..you pay for the shipping Gunner EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW! |
#17
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
Tom Gardner wrote:
(...) You have amazing vision, that's exactly what I want to replace, it's not tolerant of hard/soft/dry/oily wire. Ah. In that case I would press the gear on to the end of a combined clutch/brake. I would run the drive motor continuously and feed the wire by actuating the clutch, then I would throw out the clutch and actuate the brake at the end of 'stroke'. Heck, for your app, you could use opposite poles of a SPDT relay. If the brake isn't on, the clutch is feeding your wire. Have a look at the combined clutch/brake units on page 27, 28 of: http://www.orttech.com/files/pdfs/em206.pdf , for example --Winston |
#18
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... F. George McDuffee fired this volley in : On Thu, 26 Jun 2008 00:37:41 -0400, "Tom Gardner" wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? Tom, we have an almost identical device feeding time fuse for cutting. The assembly consists of a one-way drum clutch inside the feed tire, moved through a portion of a revolution by a crank rod on the clutch whose outer end is moved an air cylinder. It moves the fuse from 1/2" to 4.10 inches per stroke, and has nearly zero backlash (for accuracy). I think that setup is simpler yet than what you described, and does exactly the same function -- precisely and repeatedly for years without any maintenance. LLoyd It's similar to the way we feed staple wire but that uses a mechanical linkage and a ratchet and pawl rather than a one-way clutch. This is still in the running because it IS so simple, |
#19
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Thu, 26 Jun 2008 16:13:43 -0400, "Tom Gardner"
wrote: "Gunner" wrote in message .. . On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner" wrote: "Gunner" wrote in message ... On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote: On Jun 25, 10:37 pm, "Tom Gardner" wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. They make pneumatic rotary actuators to do exactly what you want, turn a shaft through a partial revolution and back. Kind of like a super- sized version of the old vacuum windshield wiper motor, uses a vane in a chamber driven by pressure, not vacuum. Might explain why you don't see a geared actuator like you describe. Unless you've got a lot of scrap parts laying around, might be the cheaper way to go! Stan I thought I sent one of those to Tom already? Gunner I didn't see it, I'd be interested in purchasing one if you still have one! Geeze....email me your freight info again..Since Ive been on a kick to trash stuff...Im down to the pneumatics section in the stacks O stuff Tell you what...Ill email you pictures of the stuff..and if you want..Ill ship you the entire lot. Might be several thousand pounds of cylinders, etc etc. All NOS, ablit some has some surface rust in non critcal places Free..you pay for the shipping Gunner EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW! Is that a yes, or a no? Or did you just grab your chest? G Say..you dont need v and timing belts do you? If you dont mind picking out the leaves and the dead bugs, Ive got a 4x4x5 steel container filled with them.' Probably a thousand or so in there, all NOS, Gates, Martin, Browning, long, short, skinny, fat..As and Bs, etc Same deal Gunner |
#20
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Thu, 26 Jun 2008 16:13:43 -0400, "Tom Gardner"
wrote: "Gunner" wrote in message .. . On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner" wrote: "Gunner" wrote in message ... On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote: On Jun 25, 10:37 pm, "Tom Gardner" wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. They make pneumatic rotary actuators to do exactly what you want, turn a shaft through a partial revolution and back. Kind of like a super- sized version of the old vacuum windshield wiper motor, uses a vane in a chamber driven by pressure, not vacuum. Might explain why you don't see a geared actuator like you describe. Unless you've got a lot of scrap parts laying around, might be the cheaper way to go! Stan I thought I sent one of those to Tom already? Gunner I didn't see it, I'd be interested in purchasing one if you still have one! Geeze....email me your freight info again..Since Ive been on a kick to trash stuff...Im down to the pneumatics section in the stacks O stuff Tell you what...Ill email you pictures of the stuff..and if you want..Ill ship you the entire lot. Might be several thousand pounds of cylinders, etc etc. All NOS, ablit some has some surface rust in non critcal places Free..you pay for the shipping Gunner EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW! Oh..if you take the belts...Ill toss in all the right angle drives, most of the Reeves drives, lovejoy couplers and most of the 3ph electric motors, leaving only a few of the machine tool specific motors. And any and all pneumatic valves, solenoids, manifolds etc..though it might take another pallet. Or 2. Or another one of those 4x4x5 scrab bins.... Frankly..Id rather you had them, than give them to the scrappers. Oh..and of course, all the Linear ways, ballscrews etc I already have boxed for you...that I keep forgetting to ship. Need any welding rod or wire? Gunner |
#21
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Thu, 26 Jun 2008 16:13:43 -0400, "Tom Gardner"
wrote: "Gunner" wrote in message .. . On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner" wrote: "Gunner" wrote in message ... On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote: On Jun 25, 10:37 pm, "Tom Gardner" wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. They make pneumatic rotary actuators to do exactly what you want, turn a shaft through a partial revolution and back. Kind of like a super- sized version of the old vacuum windshield wiper motor, uses a vane in a chamber driven by pressure, not vacuum. Might explain why you don't see a geared actuator like you describe. Unless you've got a lot of scrap parts laying around, might be the cheaper way to go! Stan I thought I sent one of those to Tom already? Gunner I didn't see it, I'd be interested in purchasing one if you still have one! Geeze....email me your freight info again..Since Ive been on a kick to trash stuff...Im down to the pneumatics section in the stacks O stuff Tell you what...Ill email you pictures of the stuff..and if you want..Ill ship you the entire lot. Might be several thousand pounds of cylinders, etc etc. All NOS, ablit some has some surface rust in non critcal places Free..you pay for the shipping Gunner EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW! If you are interested, call me. You should have the number Gunner |
#22
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
Gunner wrote:
SNIP Geeze....email me your freight info again..Since Ive been on a kick to trash stuff...Im down to the pneumatics section in the stacks O stuff Green LED's? G SNIP Gunner -- Steve Walker (remove wallet to reply) |
#23
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Thu, 26 Jun 2008 16:13:43 -0400, with neither quill nor qualm, "Tom
Gardner" quickly quoth: "Gunner" wrote in message .. . Geeze....email me your freight info again..Since Ive been on a kick to trash stuff...Im down to the pneumatics section in the stacks O stuff Tell you what...Ill email you pictures of the stuff..and if you want..Ill ship you the entire lot. Might be several thousand pounds of cylinders, etc etc. All NOS, ablit some has some surface rust in non critcal places Free..you pay for the shipping Gunner EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW! I take it that that is an affirmative, Tawm? guffaw I'm still working on the free stuff I got from him eons ago. -- Deep doubts, deep wisdom; small doubts, little wisdom. --Chinese Proverb ---- |
#24
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
"Winston" wrote in message news:EPS8k.55$BR.3@trnddc06... Tom Gardner wrote: (...) You have amazing vision, that's exactly what I want to replace, it's not tolerant of hard/soft/dry/oily wire. Ah. In that case I would press the gear on to the end of a combined clutch/brake. I would run the drive motor continuously and feed the wire by actuating the clutch, then I would throw out the clutch and actuate the brake at the end of 'stroke'. Heck, for your app, you could use opposite poles of a SPDT relay. If the brake isn't on, the clutch is feeding your wire. Have a look at the combined clutch/brake units on page 27, 28 of: http://www.orttech.com/files/pdfs/em206.pdf , for example --Winston Interesting, a quick calc says I need 0.2 hp motor. Motor and clutch won't fit in the amount of room I have available...easily. But, there are many, many ways to skin a cat. |
#25
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
"Gunner" wrote in message ... On Thu, 26 Jun 2008 16:13:43 -0400, "Tom Gardner" wrote: "Gunner" wrote in message . .. On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner" wrote: "Gunner" wrote in message m... On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote: On Jun 25, 10:37 pm, "Tom Gardner" wrote: I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms. I'm thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack gear that would engage the round gear. No, I won't do it with a servo! I'm thinking a 1/2" round rack gear in a tube with Thomson linear bearings and a scallop cut in the middle of the tube to expose teeth to the round gear. This seems simple and cheap. In fact, it's so simple it would seem that it should be an off-the-shelf item! I just assume it would be easier to do with round rack than square rack. Is this available or did I invent a new wheel? The gear would just spin back and forth and the air cylinder/rack will have an adjustable stop to get my 80 to 100 degrees rotation. The round gear will have a one-way clutch installed because I only want the one direction of shaft rotation. The shaft will power a wire feed mechanism to feed 3" to 3-1/4" of wire. They make pneumatic rotary actuators to do exactly what you want, turn a shaft through a partial revolution and back. Kind of like a super- sized version of the old vacuum windshield wiper motor, uses a vane in a chamber driven by pressure, not vacuum. Might explain why you don't see a geared actuator like you describe. Unless you've got a lot of scrap parts laying around, might be the cheaper way to go! Stan I thought I sent one of those to Tom already? Gunner I didn't see it, I'd be interested in purchasing one if you still have one! Geeze....email me your freight info again..Since Ive been on a kick to trash stuff...Im down to the pneumatics section in the stacks O stuff Tell you what...Ill email you pictures of the stuff..and if you want..Ill ship you the entire lot. Might be several thousand pounds of cylinders, etc etc. All NOS, ablit some has some surface rust in non critcal places Free..you pay for the shipping Gunner EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW! If you are interested, call me. You should have the number Gunner I will call! I can't use a lot of that stuff but pneumatics and linear stuff always comes in handy. I can't believe you aren't listing it all on eBay. For every ass, there's a seat. |
#26
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
"Larry Jaques" wrote in message ... On Thu, 26 Jun 2008 16:13:43 -0400, with neither quill nor qualm, "Tom Gardner" quickly quoth: "Gunner" wrote in message . .. Geeze....email me your freight info again..Since Ive been on a kick to trash stuff...Im down to the pneumatics section in the stacks O stuff Tell you what...Ill email you pictures of the stuff..and if you want..Ill ship you the entire lot. Might be several thousand pounds of cylinders, etc etc. All NOS, ablit some has some surface rust in non critcal places Free..you pay for the shipping Gunner EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW! I take it that that is an affirmative, Tawm? guffaw I'm still working on the free stuff I got from him eons ago. -- Deep doubts, deep wisdom; small doubts, little wisdom. --Chinese Proverb ---- The down side of free stuff is when you have to replace it, just TRY and find that model! |
#27
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
"Ned Simmons" wrote in message ... On Thu, 26 Jun 2008 11:14:33 -0400, "Tom Gardner" wrote: We currently use a rather large urethane bumpers and they get the crap beat out of them even though the striker is 1" in diameter. Have you seen the Ace Tubus bumpers? I've used a few and they seem to work better than plain urethane bumpers, though I haven't tried them in an app where they get really beat on. McMaster carries a limited selection. http://www.acecontrols.com/PDF/TUBUS...log%200906.pdf -- Ned Simmons Damn Ned, you're a handy guy to know! Why can't I find these kind of things that would make my life easier? |
#28
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
"Karl Townsend" wrote in message news.com... For only about 90 degrees of motion you don't need the rack. just use the crank shaft - connecting rod rod type idea. That is, an air cylinder connected to a shaft with a lever arm. A short lever arm makes for very fast motion, less torque. Karl This is looking to be the best option. I talked to a couple of "Rotary Actuator" manufacturers and they both balked when I told them I needed 250 ms half-cycle time. One second seems to be their comfort zone. |
#29
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On Fri, 27 Jun 2008 00:09:12 -0400, with neither quill nor qualm, "Tom
Gardner" quickly quoth: "Larry Jaques" wrote in message .. . On Thu, 26 Jun 2008 16:13:43 -0400, with neither quill nor qualm, "Tom Gardner" quickly quoth: "Gunner" wrote in message ... Geeze....email me your freight info again..Since Ive been on a kick to trash stuff...Im down to the pneumatics section in the stacks O stuff Tell you what...Ill email you pictures of the stuff..and if you want..Ill ship you the entire lot. Might be several thousand pounds of cylinders, etc etc. All NOS, ablit some has some surface rust in non critcal places Free..you pay for the shipping Gunner EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW! I take it that that is an affirmative, Tawm? guffaw I'm still working on the free stuff I got from him eons ago. -- Deep doubts, deep wisdom; small doubts, little wisdom. --Chinese Proverb ---- The down side of free stuff is when you have to replace it, just TRY and find that model! Yeah, I'm still trying to locate worm gears for the old Wilton 4x6 saur I got. I should get tires while I'm at it, and by then, I'll be up to the price of a new HF 4x6. Hmmm... Neely Bearing wanted $8 and change for the new idler General (Chinese) 62022 bearing for the drill press, with retaining ring. Another local bearing place, Applied Industrial Technologies wanted $20 for an identical SKF bearing and no snap ring. I should probably press that together one of these days. I already had a spare LinkBelt for it. I dare say that even a Chinese bearing will likely outlast me. OK, time for the Heller syllabus... -- Deep doubts, deep wisdom; small doubts, little wisdom. --Chinese Proverb ---- |
#30
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
--Hiya; chiming in a little late here, but to see a good
implementation of what you want to build you might head over to battlebots.com and check out a heavyweight called The Judge. Before it was dismembered by a spinbot it had a spiked arm on it that could punch holes in 1/4" steel plate. Heh. -- "Steamboat Ed" Haas : "Hold on! we're passing Hacking the Trailing Edge! : through the moronosphere!" www.nmpproducts.com ---Decks a-wash in a sea of words--- |
#31
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On 2008-06-27, Larry Jaques novalidaddress@di wrote:
On Fri, 27 Jun 2008 00:09:12 -0400, with neither quill nor qualm, "Tom Gardner" quickly quoth: [ ... ] The down side of free stuff is when you have to replace it, just TRY and find that model! Yeah, I'm still trying to locate worm gears for the old Wilton 4x6 saur I got. I should get tires while I'm at it, and by then, I'll be up to the price of a new HF 4x6. Hmmm... O.K. First question: "saur" -- sort for "dinosaur" to indicate the age, or just a creative spelling of "saw"? Second -- does the Wilton 4x6 actually *have* tires? The import one which I have from MSC has a cast iron wheel with a flange and a groove to clear the set of the 1/2" blade teeth -- no tire. I thought that all of the 4x6 saws were like this. Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
#32
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On 28 Jun 2008 03:27:44 GMT, with neither quill nor qualm, "DoN.
Nichols" quickly quoth: On 2008-06-27, Larry Jaques novalidaddress@di wrote: On Fri, 27 Jun 2008 00:09:12 -0400, with neither quill nor qualm, "Tom Gardner" quickly quoth: [ ... ] The down side of free stuff is when you have to replace it, just TRY and find that model! Yeah, I'm still trying to locate worm gears for the old Wilton 4x6 saur I got. I should get tires while I'm at it, and by then, I'll be up to the price of a new HF 4x6. Hmmm... O.K. First question: "saur" -- sort for "dinosaur" to indicate the age, or just a creative spelling of "saw"? Hey, I got it from Gunner. It's a bit of both. g Second -- does the Wilton 4x6 actually *have* tires? The import one which I have from MSC has a cast iron wheel with a flange and a groove to clear the set of the 1/2" blade teeth -- no tire. I thought that all of the 4x6 saws were like this. That's the way this is, but someone recently mentioned tires on a metalworking bandsaw and it got me thinking that maybe I was missing something. This thing's pretty clapped out and the local ACE hardware stores now have ShopFox 4x6ers in stock for $149, so... -- Deep doubts, deep wisdom; small doubts, little wisdom. --Chinese Proverb ---- |
#33
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On 2008-06-28, Larry Jaques novalidaddress@di wrote:
On 28 Jun 2008 03:27:44 GMT, with neither quill nor qualm, "DoN. Nichols" quickly quoth: [ ... ] O.K. First question: "saur" -- sort for "dinosaur" to indicate the age, or just a creative spelling of "saw"? Hey, I got it from Gunner. It's a bit of both. g O.K. Good enough. Second -- does the Wilton 4x6 actually *have* tires? The import one which I have from MSC has a cast iron wheel with a flange and a groove to clear the set of the 1/2" blade teeth -- no tire. I thought that all of the 4x6 saws were like this. That's the way this is, but someone recently mentioned tires on a metalworking bandsaw and it got me thinking that maybe I was missing something. This thing's pretty clapped out and the local ACE hardware stores now have ShopFox 4x6ers in stock for $149, so... Hmm ... to put tires on it, you will need to totally re-turn the wheels -- get rid of the flange, and put in a groove for the root of the tires. And I don't know whether tires will work well with the design of the 4x6 -- toss in the sharp twist to the blades, and the short distance from the guides to the wheels, and I'm not sure what will happen. The benefit of tires is the ability to use a wide range of blade widths, and to make them self centering on large wheels which can't be easily tilted. There are tires on my Emco three-wheeled saw (with fiberglass-reinforced plastic wheels), but the blade is not twisted like the 4x6 does, and the guides are less aggressive. I would suggest keeping the flanged wheels for the 4x6 and just using it as a cutoff saw (it is pretty useless as a vertical saw -- not enough throat to allow much work guiding) and get something better with wheels for freehand sawing to shapes. That's what I do with the Emco three-wheeled one, which has three belt positions including one which gives a high enough speed to make sawing aluminum a lot better. But that is one tiny little belt -- some of these days it is bound to pop. I just don't have room for a proper floor-standing vertical. The 3-wheeler came from an eBay auction. Emco seems to have discontinued it. Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
#34
Posted to rec.crafts.metalworking
|
|||
|
|||
Pneumatic rack and pinion drive
On 29 Jun 2008 00:15:39 GMT, with neither quill nor qualm, "DoN.
Nichols" quickly quoth: On 2008-06-28, Larry Jaques novalidaddress@di wrote: On 28 Jun 2008 03:27:44 GMT, with neither quill nor qualm, "DoN. Nichols" quickly quoth: [ ... ] O.K. First question: "saur" -- sort for "dinosaur" to indicate the age, or just a creative spelling of "saw"? Hey, I got it from Gunner. It's a bit of both. g O.K. Good enough. Second -- does the Wilton 4x6 actually *have* tires? The import one which I have from MSC has a cast iron wheel with a flange and a groove to clear the set of the 1/2" blade teeth -- no tire. I thought that all of the 4x6 saws were like this. That's the way this is, but someone recently mentioned tires on a metalworking bandsaw and it got me thinking that maybe I was missing something. This thing's pretty clapped out and the local ACE hardware stores now have ShopFox 4x6ers in stock for $149, so... Hmm ... to put tires on it, you will need to totally re-turn the wheels -- get rid of the flange, and put in a groove for the root of the tires. And I don't know whether tires will work well with the design of the 4x6 -- toss in the sharp twist to the blades, and the short distance from the guides to the wheels, and I'm not sure what will happen. Waaaay too much work. I thought they might have used very thin tires on the stepped wheel. The benefit of tires is the ability to use a wide range of blade widths, and to make them self centering on large wheels which can't be easily tilted. There are tires on my Emco three-wheeled saw (with fiberglass-reinforced plastic wheels), but the blade is not twisted like the 4x6 does, and the guides are less aggressive. I would suggest keeping the flanged wheels for the 4x6 and just using it as a cutoff saw (it is pretty useless as a vertical saw -- not enough throat to allow much work guiding) and get something better with wheels for freehand sawing to shapes. That's what I do with the Emco three-wheeled one, which has three belt positions including one which gives a high enough speed to make sawing aluminum a lot better. But that is one tiny little belt -- some of these days it is bound to pop. I just don't have room for a proper floor-standing vertical. The 3-wheeler came from an eBay auction. Emco seems to have discontinued it. I'll likely eBay it to get a good downpayment on a new 4x6. I'm finding much less time to fiddle when I'm in the shop nowadays. Besides, I like white tools, though Griz Green is also a fave color. The lighter the tools in my shop, the brighter the shop. Now to go clean the shop out so I could possibly _work_ out there again some day soon... -- Such is the irresistible nature of truth that all it asks, and all it wants, is the liberty of appearing. -- Thomas Paine |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
mount towel rack/magazine rack to ceramic tile | Home Repair | |||
Rack & Pinion kit? | UK diy | |||
OT, 1990 Mustang rack and pinion. | Metalworking | |||
Pneumatic Finish Nailer or pneumatic stapler | Home Repair | |||
rack and pinion | Metalworking |