Announcement

Collapse
No announcement yet.

Something old--Something Older---

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Something old--Something Older---

    This morning its too cold to play outside, and I'm bored.--Which is not necessarily a bad thing. I have been perusing my booklet "507 Mechanical Movements" by Henry T Brown, looking for some kind of intriguing mechanical "eye candy" to possibly build. This is a little booklet choc full of all kind of nifty mechanical devices that were invented at the beginning of the mechanical revolution. Some of them were great devices, which are still in use today in modern machinery. Some are ideas that worked and were used for a period of time when mechanical things were transitioning from steam power to gasoline power, and some of them were probably only ever built once, just to see if they would work. A device that caught my eye this morning is item #27, which is listed as "Multiple Gearing" with the following description:--"A recent invention. The smaller triangular wheel drives the larger one by the movement of its attached friction-rollers in the radial grooves." There are no measurements nor geometric relationships given, only the picture shown here. I thought "Hmmmm---That's interesting!!! I wonder if I can replicate that and sus out the geometric relationships in Solidworks?" Good wife was still in bed sleeping, so I snuck downstairs to my office, fired up the computer, and found out that "By Golly, I can!!!" Of course the next question was, what do I have to run something like that? A static display just doesn't cut it. In my room devoted to small steam and gasoline engines which I have built over the last five years, there is the sad remains of what once was a very proud "Hit and Miss" air engine originally designed by Chuck Fellows over on HMEM. It ran marvellously, but I had cannibalized parts off it and used them for other purposes, and the main corpse has been laying around for two years now, waiting to be resurrected as something new. A few measurements and some deep thought has suggested that I should be able to use it as the main engine for a dynamic display of this marvelous old "Multiple Gearing" idea. So--as the summer advances and I get downtime from other work and play, I will be building this.----Brian


    Brian Rupnow

  • #2
    That's going to be cool, it is mechanical eye candy - at least it is to me - it's allot like a geneva mechanism without the stopping points...

    It's important when figuring out load factors that no matter how tight you make the tolerance there's only one real drive flange and it's the lower one due to it exceeding the speed drive arc ratio of the others,,, the others are basically just departure and return guides...

    Comment


    • #3
      I have two questions,

      1. What is mechanism 29 called?

      2. Is something similar inside a Woodward governor?
      Gene

      Comment


      • #4
        29 will advance the driven wheel one tooth per rev of the driving wheel. What's that useful for is anybody's guess. Bob.

        Comment


        • #5
          Well that could be useful just for being simple gearing, its a 2 to 1 ratio so that means if someone got fancy they would use it to drive a camshaft for a little ICE (hint to Bri) and your doing it without having to make gears, and it's spinning in the same direction which gears do not unless you make the large one internal...

          but there's a clause that Brian has to be aware of,,, it's not steady, the final drive is pulsating especially under loads much more so than gears - and to have two items of mass on each end could mean one of them tears the other one (or mounts or whatever) apart...
          Last edited by A.K. Boomer; 05-26-2013, 03:21 PM.

          Comment


          • #6
            Bob is the like the auto downfeed on a hand cranked drill press?
            "Let me recommend the best medicine in the
            world: a long journey, at a mild season, through a pleasant
            country, in easy stages."
            ~ James Madison

            Comment


            • #7
              Exactly my thought, flylo. The feed on the post-mount drill press in my grandfather's blacksmith shop had a cam-operated pawl that engaged a gear and advanced the feed a couple of teeth per revolution of the crank handle. That feed was more or less all at once though; mechanism #29 would give much more uniform feed, I think.
              ----------
              Try to make a living, not a killing. -- Utah Phillips
              Don't believe everything you know. -- Bumper sticker
              Everybody is ignorant, only on different subjects. -- Will Rogers
              There are lots of people who mistake their imagination for their memory. - Josh Billings
              Law of Logical Argument - Anything is possible if you don't know what you are talking about.
              Don't own anything you have to feed or paint. - Hood River Blackie

              Comment


              • #8
                I think that #29 is a crude drawing of what is what I believe is a spiral crown gear and pinion. The pinion gear that engages it is on a splined shaft. As the crown gear rotates the pinion it will change the ratio to the movement of the driven splined shaft. The pinion has shoulders that guide it along the crown.

                I don't have that wonderful book. But I think the drawing is spoiling the elegant nature and possible purpose of the design. Thus my question. I was wondering if in use it could be used to control the amount of curve of throttle adjustment for an AC generator that had to be very closely controlled as to CPS.
                Gene

                Comment


                • #9
                  Of course, nothing in life is easy. I lost all of the 3D cad models of this engine a few years ago when I had a major computer crash. Fortunately, I have many of the files of my different steam engines stored as pdf files on a web hosting site, so I was able to download a set of the plans and recreate all the solid models. When I first built this engine and made the drawings based on Chuck Fellows design, I posted the link as a free download, and I see that it has been downloaded 588 times. Now that I have recreated the models, I can move foreword with the "Multiple Gearing" design.
                  Brian Rupnow

                  Comment


                  • #10
                    That #29 looks like a basic worm wheel, except it is radial and not axial movement. Would be useful for applications that require something like a worm gear.
                    Amount of experience is in direct proportion to the value of broken equipment.

                    Comment


                    • #11
                      Here's the book if anyone wants it.

                      http://www.pdnotebook.com/2010/02/50...movements-pdf/
                      .

                      Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



                      Comment


                      • #12
                        Here is something I made many moons ago, just to see if it would work. I had seen 2-slider BS Grinders, and wondered if 3 sliders would work. It did, and many people have really enjoyed turning the knob to see the sliders not crash into each other. Yes, it is a 2:1 ratio.

                        Note: sliders are attached to spider with specially-made shoulder screws through a hole in the center of the disk (not visible in this shot).
                        If ignorance is bliss, why aren't there more happy people?

                        Comment


                        • #13
                          #29 does not have much to commend it except that it might be easy to make. It has the same mechanical ratio as a single start worm gear which could be used with the same alignment of the shafts but the friction is enormous compared to a worm.

                          Comment


                          • #14
                            29 is like the scroll in a lathe's chuck. It's scroll that pulls a rack or turns a gear.

                            That gives me some ideas.


                            Dan
                            At the end of the project, there is a profound difference between spare parts and extra parts.

                            Comment


                            • #15
                              Originally posted by Jaakko Fagerlund View Post
                              That #29 looks like a basic worm wheel, except it is radial and not axial movement. Would be useful for applications that require something like a worm gear.
                              It looks useful for the outfeed for a boring head. The star wheel feeds give you all the feed at once whereas this is a smooth continual one. Gearing would provide different rates and the in and out feed.
                              .
                              "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

                              Comment

                              Working...
                              X