US2660380A

US2660380A - Paper feed mechanism for recorders

Info

Publication number: US2660380A
Application number: US156286A
Authority: US
Inventors: Birt G Blackman; Donald O Nelson
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1950-04-17
Filing date: 1950-04-17
Publication date: 1953-11-24
Anticipated expiration: 1970-11-24

Description

Nov. 24, 1953 B. G. BLACKMAN ET AL PAPER FEED MECHANISM FOR; RECORDERS Filed April 17, 1950 INVENTORS AND B. G. BLACKMAN A 0. a 0. W m u m m m wnmlumunr hm |||l ll D. O. NELSON ATTORNEY Patented Nov. 24, 1953 PAPER FEED MECHANISM FOR RECORDERS Birt G. Blackman and Donald 0. Nelson, Los Angeles, CaliL, assignors to Bendix Aviation Corporation, South Bend, 11111., a corporation of Delaware Application April 17, 1950, Serial No. 156,286

3 Claims; 1

This invention relates to recording instruments in which a paper tape is fed from a supply spool past a recording station to a take-up spool, and has to do particularly with a mechanism for driving or moving the tape. More specifically, the invention relates to that type of mechanism in which the tape must be positively fed at a uniform speed, and the take-up spool has flanges for contacting the edges of the tape and maintaining the tape in a fixed path as it feeds past the recording station,

An object of the invention is to provide a tapedriving mechanism, adapted to be positioned between the recording station and take-up spool, that pulls the tape positively at a constant speed past the recording station and delivers it to the flanged take-up spool, without imparting a lateral force to the tape that would interfere with its lateral guidance by the flanges of the take-up spool.

Other more specific objects and features of the invention will appear from the description to follow of a preferred embodiment thereof.

In many recorders for making continuous recordings on a paper tape, it is important that the tape he moved at a constant speed past the recording station and be maintained in a fixed lateral position at the recording station. One known method of accomplishing this is to pull the tape past the recording station by passing it between a pair of toothed or knurled rollers one of which is positively driven at a desired speed, and drawing the tape from the rollers onto a flanged spool which is yieldably driven to roll up the tape only as fast as it is delivered by the feed rollers. It has been found in practice that even with the greatest care in the manufacture of the drive rollers, as previously described, they sometimes tend to feed the paper faster near one edge than the other, thereby tending to cause the paper to ride laterally out of its desired path. The flanges on the take-up spool are supposed to prevent any such lateral wandering of the tape, but in practice, particularly with some types of paper tapes, the strength of the tape is insufficient to overcome the lateral force applied thereto by the driving rollers, with the result that the edge of the paper is forced agains one flange of the take-up spool so strongly that it tears or folds at the edge as it winds onto the take-up spool.

In accordance with the present invention this tendency toward lateral movement of the tape by the drive rollers is overcome by providing one of the drive rollers with a narrow knurled midsection, and slightly recessing the end portions of the roller. This applies the main driving force over a narrow area near the center of the tape and does not tend to wind one edge of the tape faster than the other, the flanges on the take-up spool being free to exert their proper centering effect on the tape without impressing forces on the edge of the tape that might damage it. An application of the invention will now he described in detail with reference to the drawing, in which:

Fig. l is a perspective view showing the tape feed mechanism of a depth recorder.

Fig. 2 is a, detail view, partly in section, of the drive rollers of the recorder, the view being taken in the plane IIII of Fig. l; and

Fig. 3 is a cross section taken in the plane IIIIII of Fig. '2.

Referring to Fig. l, the recorder shown therein comprises a frame plate iii, across the front of which a paper record tape 1 l is drawn. This tape is fed from a supply roller (not shown) around an idler roller 12 positioned at the right edge of the plate It, across the front of the plate back of a ring-type stylus carrier I3, thence around an idler pulley H! at the left edge of the plate 10. Thereafter the paper is drawn around a first feed roller l5, then between the feed roller is and a second feed roller 16, then around the feed roller l6 and onto a take-up spool ll having flanges I8 and I!) at its opposite ends, which are spaced apart approximately the width of the tape 8 I.

In the particular recorder shown, the ring type stylus I4 is constantly rotated, and a stylus 29 is periodically energized to produce a line 2| on the paper tape. However, the particular construction of the recording mechanism does not constitute a part of the present invention and will not be further described.

The drive roller I6 is positively driven at constant speed. Thus, its supporting shaft 22 extends through a bearing journal in an upper frame plate 23 and has on its upper end a worm wheel 24 that meshes with a worm 25 on the shaft 26 which is driven through a gear train consisting of

gears

28 and 29 from the shaft 30 of a motor 21. In the particular recorder shown, the motor shaft 30 is extended through the front plate l0 and carries a drive pinion 32 which meshes with gear teeth on the stylus carrier [3 to rotate the latter.

As best shown in Fig. 2, the lower end of the shaft 22 of the roller I6 is journaled in a bearing in a lower frame plate 33 so that the roller I6 is supported in fixed relation as nearly perpendicular as possible to the path of the paper tape ll The idler roller l5 has a shaft 34 which is mounted in

slots

35 and 36 in the

frame plates

23 and 33 respectively so that the roller l5 has freedom of movement toward and away from the roller IS. The idler roller I5 is yieldably urged toward the drive roller 16 by

tension springs

38 and 39 which extend around pulleys 40 and 4! which are mounted by hearings on opposite ends i the shaft M. The ends of the

tension springs

38 and 39 are engaged by adjusting screws 42 which extend through cars 43 projecting from the

frame plates

23 and 33.

The take-up spool I! is driven by a pulley 45 on the lower end of the spool shaft below the frame plate 33, which pulley is linked by a hellcal tension spring belt 4'! to a drive pulley 48 on the lower end of the shaft 22 of the drive roller IE. The pulley 43 always rotates faster than the pulley 45, and the spring 41 slips as necessary to maintain a constant take-up torque on the spool 11.

The mechanism so far described is old and. in this old structure both the drive roller l5 and the idler roller it had meshing teeth or serration extending their full lengths. The present invention resides solely in the provision of only a small serrated portion its on the drive roller l6, near its center, as best shown in Fig. 2. The serrations in the zone lfia of roller 16 mesh with the full length serrations of the idler roller l5 and tend to crinkle the paper as it passes between the rollers, as shown in Fig. 3. This provides such a positive engage "sent between the rollers and the paper that sli page therebetween is practically impossible. However, since the drive is applied substantially only at the center portion of the paper tape, it cannot tend to pull one edge or the tape faster than the other. Therefore the tape flows from the drive roller 16 onto the take-up spool l'l between the flanges l3 and i9 thereon.

It is found in practice that if for any reason the tape tends to ride more heavily against one flange of the take-up spool, say the flange I B, the lateral thrust of the flange against the edge of the tape is suflicient to start moving away from the flange, and this movement not interfered with by the drive rollers. The result is that before any pressure on the edge of the tape sufficient to it can result, the alinement of the paper between the flanges of the take-up spool is restored.

As shown in Fig. the smooth portions 16b on opposite sides of the central serrated portion lea oi the roller 16 are recessed to eliminate the serrations, and are therefore of slightly smaller average diameters. The result is that as it is wrapped around the drive roller IS the tape tends to become concave on the side next to the roller Although for the purpose of explaining the invention, a particular embodiment thereof has been shown and described, obvious modifications will occur to a person skilled in the art, and we do not desire to be limited to the exact details shown and described.

We claim:

1. A tape pulling mechanism for drawing a tape past a predetermined position and maintaining lateral alinement of the tape at said position, said mechanism comprising: a flanged take-up spool having flanges spaced the width of the tape, means rotatably supporting said spool in spaced relation to said predetermined position, and means for applying torque to said spool to wind up tape delivered thereto; a pair of feed rollers positioned between said spool and said position adapted to engage said tape therebetween; means for urging said rollers together to grip the tape therebetween; and means for positively rotating one of said rollers to feed the tape at a desired speed; in which one of said rollers has a peripheral surface of uniform dieuieter extending the full width of said tape, and the other roller has a central periph a1 surface zone of uniform diameter and subs h than said tape and has zones of lesser, uniform diameter extending from the margins of said central zone to the ends of the roller, said central peripheral surface zone being shorter than said zones of lesser diameter.

2. A mechanism according to claim 1 in which said peripheral surface of said one roller is 5&1"- rate and said central zone of said other roller has serrations intermeshing with the serrations of said one roller.

3. A mechanism according to claim 1 in which the axes of said rollers lie in. a plane approximately normal to a plane extending from said predetermined position to said talre-up spool, and said tape wraps around one roller prior to its passage between the rollers, and wraps around the other roller following its passage therebetween.

IRT G. BLACKMAN. DONALD O. NELS Ol' l.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,153,843 Greene Sept. 14%, 1915 1,331,242 Convery Feb. 17, 19:; 2,059,879 La Pierre Nov. 3, 1935 2,325,063 Krueger July 27, 1943 2,408,320 Kuhlik Sept. 24%, 19-16 2,454,021 Wilson Nov. 16, ill l8 2,532,563 Markle Dec. 5, 1950 2,564,274 Pratt et a1. Aug. l l, 1051 FOREIGN PATlllliS Number Country Date 27,486 Great Britain Dec. 30, 189B