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Need creative engineering advice

G

Gennady

Active Member
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Hello folks. I am rebuilding older BP longitudinal power feed gearbox.
Shifter handle is missing- probably was broke and thrown out. Now I need to replicate something similar - I made a keyed collar for the sleeve and bent a handle itself from steel bar .Now I need to attach lock pin which will be moving through positions on the casting. I can make it adjustable in axial position ( see white arrow on the handle ) I can mill a slot along the handle, but I also will need some adjustment in cross direction as it defines proper gear mesh inside the gearbox. What might be creative solution to make lock pin adjustment in two directions?
 
I take it it’s pinned to the shaft? To start I’d mill the top flat because it looks like the bend would interfere with good sliding action I think that would be a first step.
 
If I understand the challenge correctly you need the ability to slightly adjust the position of the bent arm once it's in the correct slot?
If that's correct, maybe a pin that's on a short arm that pivots around the handle which can be tightened once the correct mesh is achieved.

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OK. Bent arm will be welded to the collar. All this assembly is sliding in/out while fixed to the sleeve. I am attaching original design for better understanding. Handle - bent part on my photos is F31 , locking pin is F43.

@Tom - Locking pin is not sliding along the handle - it is adjusted and tightened once and forever. Handle is rotating and sliding in and out on sleeve F30.

@David - I like your idea , basically you suggest to make locking pin eccentric so it can be adjusted both ways.
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Gennady said:
OK. Bent arm will be welded to the collar. All this assembly is sliding in/out while fixed to the sleeve. I am attaching original design for better understanding. Handle - bent part on my photos is F31 , locking pin is F43.

@Tom - Locking pin is not sliding along the handle - it is adjusted and tightened once and forever. Handle is rotating and sliding in and out on sleeve F30.

@David - I like your idea , basically you suggest to make locking pin eccentric so it can be adjusted both ways.
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Yup, that's what I was thinking. Your description is better than mine :)
 
OK. Here is what I came with modeling that, rather quick and dirty, in F360. Yellowish part is lock pin itself which is sliding in the busing - beige part. Bushing has eccentric bore which allows locking pin to be adjusted cross handle approx 4 mm. I believe this is enough to get gears into proper mesh. along the handle bushings is adjusted moving it inside slot and securing it with low profile nut (not shown).

Any critics?

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Gennady said:
OK. Here is what I came with modeling that, rather quick and dirty, in F360. Yellowish part is lock pin itself which is sliding in the busing - beige part. Bushing has eccentric bore which allows locking pin to be adjusted cross handle approx 4 mm. I believe this is enough to get gears into proper mesh. along the handle bushings is adjusted moving it inside slot and securing it with low profile nut (not shown).

Any critics?

View attachment 50668
Click to expand...
That's brilliant!
 
Here is my progress with fabrication of gear box shift lever. First picture is bushing with eccentric bore and nut. Second picture is bushing with inserted locking pin and nut. Third - lever itself, quite crude welding , but this is what I can do :) , Finally - shifter is assembled and gears are meshed properly.

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Now it is a time to deal with Viagra stuff - need to extend replacement motor shaft

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What you see is mounting flange for the original motor and worm gear inside

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I made a centering washer to fit in this bore and provide centering guidance for the treadmill motor.

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I am contemplating a bit - to cut a threaded end and to make an extender?
 
Actually, quite a fiasco…

First I realized that I miscalculated length of extender. That is not end of a story as I made shaft for worm gear quote long, so I made a special washer.

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Then I cut a key slot and squished motor mounting part between vise jaw and v-block - it was not fitting motor shaft anymore. I had to install it it again on lathe an open bore a bit That made fit way too loose. Unacceptable

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I installed motor anyway, just to make sure it all fits an moving gears.

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That was working fine.


Now I need to redo an extender with modifications and with different sequence of operations. Slot has to be cut before boring hole for the motor shaft. Lesson learned.
 
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Sounds like you mounted it in the vise on the bored/larger section causing it to collapse and not the smaller diameter section?
 
Yes, exactly, this was my mistake.

BTW. wondering if somebody knows. Do these gearboxes filled up with oil or just periodically oiled trough oil caps?
 
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