Have been refining the design of the power draw bar. I'm try to simplify and lower the number of parts as much as possible. I figured the guide rods could be eliminated by strengthening linear actuator. The impact socket will be used to retract the spindle lock instead of the long bolts on the sides.

     The linear actuator will use a 3/8 screw, so i can have many options. (3/8-16, 3/8-24, 3/8-8 acme.3/8-10 acme,  3/8-12 acme).  The over run spring for the actuator has been moved to the screw nut instead at the bottom. This is to make it more rigid and simpler to machine the part, plus removing the guide rod made it a must.

     The spindle lock be two interlocking dogs. In the bottom lock dog the draw bar will be "captured" to eliminate a sticking collet  from driving back and damaging something.

     A 12 point nut and socket will make engagement  more reliable. On my current system system things don't always the first time.

    In theory this is how it will work.

             Step 1  linear actuator moves down. (push out button)
             Step 2  if socket does not engage the spring inside actuator will compensate
             Step 3  slowly turn motor
             Step 4  socket engages nut (switch will verify this)
             Step 5  keep slowly turn motor ( this will turn the spindle)
             Step 6  lock dogs will engage (switch will verify this)
             Step 7 increase motor speed in reverse to loosen
             Step 8 change tool (my job)
             Step 9 increase motor speed forward to tighten (push in button)
             Step 10 move linear actuator up, socket will pull the lock dogs apart.

             Step 11 did miss any steps?

     More changes sure to come.


   

 

Power drawbar

New power draw bar

       Spent the weekend using sketchup8 designing a new power draw bar for the ORK mill. My goal is to make my current electric impact draw bar a push button operated  system, with out using any pneumatics. Instead of an air cylinder to engage the impact wrench I plan to make a linear actuator. I was thinking of using a Fergelli L16 or L12 linear actuator. But at 80.00 a piece, plus the control board and the possibility of breaking the plastic ends put them out of my price range.

        The diy linear actuator will be powered by a small gear motor and controlled by an h bridge/RC servo board circuit from the website,  lets make robots .  A  50amp smart car h bridge will  control the direction and speed of the impact wrench. In the picture below the thin plate is a pcb that will contain a diy arduino , relays and the tactile switches. I'm not sure about the LCD display yet, I might eliminate it, to simplify the design. The switch panel is made in inkscape then printed, laminated and placed over the tactile switches to make it coolant proof .

        The light blue pins will engage a locking ring on the spindle, may not need this part, will try it without it.
Trying to make it a simple add on, with out having to much wiring integrated in to the main system. The arduino sketch will have a jiggle feature to help align the nut and spindle lock, with a time out function. Will also add a circuit to put the machine in E stop when the draw bar is engaged or if there is a malfunction.  Don't want an Oooop!!! moment.

     Added some electronics from the sketchup warehouse to the pcb. Used the x-ray function to check to
make sure every thing fits.