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Antiblousing Carriage Vernier Clutch

IP.com Disclosure Number: IPCOM000082110D
Original Publication Date: 1974-Oct-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Bonafino, EJ: AUTHOR [+2]

Abstract

As shown in Fig. 1, a pin wheel forms feed tractor 10 of the prior art is driven by a pulley 12 through normally engaged toothed clutch members 14a, 14b which are urged into engagement by spring 16. A knob 18 moves shaft 20 to the right to disengage the clutch members 14a, 14b and permit feeding the form in small increments, independently of the drive pulley 12 to line up a new form.

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Antiblousing Carriage Vernier Clutch

As shown in Fig. 1, a pin wheel forms feed tractor 10 of the prior art is driven by a pulley 12 through normally engaged toothed clutch members 14a, 14b which are urged into engagement by spring 16. A knob 18 moves shaft 20 to the right to disengage the clutch members 14a, 14b and permit feeding the form in small increments, independently of the drive pulley 12 to line up a new form.

This standard design causes serious errors because of the lack of a lower set of feed tractors. As shown in Fig. 2, even when the clutch teeth 14a, 14b mesh perfectly a slack condition can exist in the form. Slow manual advance tends to make the condition worse and causes a short space to occur between the first and second lines printed. Since the length of forms spacing remains correct after the second line, all lines except the first are out of registration.

By altering the shape of the vernier teeth so that the trailing edge of the driving clutch member teeth is steep as shown on 14A and 14B in Fig. 3, and the driving face is slanted, it is possible to (1) eliminate tooth backlash tendency, (2) assure that there will always be some forward tractor motion as the teeth engage (in this way some of the blouse is taken up), and (3) establish the drive surface of the vernier at a larger diameter, so that the effect of fixed clearances in the hardware is reduced in proportion to the change in diameter.

The net effect of these three items is to appreci...