Fixed gear ratio and correction tape

AI Thread Summary
The discussion centers on the mechanics of a correction tape dispenser, particularly the fixed gear ratio between the larger gear that dispenses new tape and the smaller gear that rewinds used tape. Observers note that as the tape rolls change in size, the gear ratio should ideally approach 1:1 to accommodate this change. However, the absence of a visible clutch mechanism raises questions about how the device compensates for the fixed gear ratio. Despite initial assumptions about a sliding mechanism or clutch, further examination reveals no such features. The conversation also touches on the design of correction tapes and the potential for different mechanisms in various models, with some participants referencing patents and the lack of imitation by manufacturers. The discussion concludes with a personal anecdote about using correction methods in the past, highlighting the evolution of such tools.
Leo Liu
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I recently got a new correction tape. When I was staring at it today (ya I knew I should be studying for calc2), I noticed that the gear ratio between the two gears was notable and fixed. In particular, the bigger gear that unrolls the tape has more teeth than the smaller gear that rolls up the used tape. While it is easy to guess that the radius of the tape plate attached to the smaller gear will not exceeds that of the plate attached to the bigger gear, as the radius of the plate of new/used tape decreases/increases, the gear ratio must become closer to 1:1 to accommodate for the decreasing difference between the radii. However, the gears in my correction tape are fixed, and this prompts me to wonder how this could work.

Thanks.
 
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Nicely spotted :wink:

I think there will be a clutch somewhere on/in one of the gears.
 
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Rive said:
Nicely spotted :wink:

I think there will be a clutch somewhere on/in one of the gears.
After carefully observing the gear through the transparent case, I didn't find any clutch mechanism. I thought the used tape roll on the smaller gear might be able to slide on the shaft to compensate for the fixed gear ratio, but then I recalled that the end was taped on the shaft when I disassembled one correction tape in middle school, so this explanation was not correct.
 
Leo Liu said:
I recently got a new correction tape.
For a typewriter? o_O
 
Leo Liu said:
so this explanation was not correct.
Of course you have a specific type, while I'm thinking on a general solution, so what I suggest might not apply.
However... 😉
 
Rive said:
Of course you have a specific type, while I'm thinking on a general solution, so what I suggest might not apply.
However... 😉
First I would like to point out that by "not correct" I meant the explanation came up with.

A very interesting patent. In this case I guess my tape also uses a clutch with a different design. I am surprised that the Chinese stationary manufacturers haven't copied this design since the patent has expired in China.
 
jtbell said:
For a typewriter? o_O
Aha, now I see after a Google search that these appear to be for general "erasing" purposes. I've never used one of them, even back in the days when I prepared a lot of documents by hand in ink, e.g. physics/math homework solutions. If something became too messy because of crossed-out corrections, I simply wrote a fresh copy.
 
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