US2134391A - Reroll drive mechanism for graphic meters - Google Patents

Description

Oct. 25, 193,8. D. J. ANGUS REROLL DRIVE MECHANISM FOR GRAPHIC METERS Filed April 6, 1937 ull ATTORNEYS.

Patented Oct. 25, 1938 PATENT oFEicE REROLL DRIVE MECHANISM FOR GRAPHIC METERS Donald J. Angus, Indianapolis, Ind.

Application April 6, 1937, Serial No. 135,264

2 Claims.

It is the object of my invention to provide for graphic meters a re-roll drive mechanism which not only permits rotation of the re-roll roller in spring-winding Adirection (as in unrolling the record sheet for inspection) without danger of over-,winding the spring and without being limited by full winding of the spring, but also without undue shock stops the spring-unwinding movement of the re-roll roller if such movement is too rapid, as on breakage of the paper or failure of the supply of paper.

With that end in view, I provide in the driving mechanism for the re-roll roller a slipping clutch which slips upon undue spring-winding movement of the re-roll roller; and also provide a light-weight member frictionally connected with the re-roll roller so that it may slip under stress, and provide on that light-weight member a centrifugally operated part which cooperates with a stop-pin to stop the light-weight member and thereby gently stop the re-roll roller Without undue shock upon too rapid spring-unwinding movement of the re-roll roller.

The accompanying drawing illustrates my invention: Fig. 1 is a vertical section, substantially on the line I-I of Fig. 2, through a driving mechanism embodying my invention; Fig. 2 isv a fragmentary side elevation of the mechanism shown in Fig. l, with some parts broken away; and Figs. 3 and 4 are enlarged transverse sections, on the line 3-4 of Fig. 1, through the lightweight, centrifugally operated, frictionally mounted, stopping mechanism, with the centrifugally operated members in its inner and outer positions respectively.

The graphic meter may be of any desired type, in which a record sheet III or traveling chart is driven at predetermined speed by and over a feed-roll II, from which it passes to a re-roll roller l2 on which it is rewound. The feed-roll l I may be driven in any suitable manner, not involved in the present invention; and a graph is made on the record in any suitable manner, well understood.

The re-roll roller I2 is driven by a suitable coil spring I5, shown as windable by a key on a stem I6, which is held against backward movement by a ratchet mechanism I6'. For such driving, one end of the spring I5 is suitably connected to a gear I'I; which is connected through a train of gears to a shaft I8 carrying and drivingly connected to one end of the re-roll roller I2 in any suitable manner. As shown, that driving train includes a pinion I9 meshing with the gear I'I and xed to a gear 20, a pinion 2| meshing with the gear 2li and driving a gear 22, and a pinion 23 fast on the shaft I8 which drives the re-roll roller I2.

Between the pinion 2| and the gear 22, however, the driving connection is not positive, but frictional and slippable. To that end, the pinion 2| is fast on a shaft 25. Also fast on that shaft 25 is a disk 2S. The gear 22 is loose on the shaft 25; but it lies in frictional engagement with the disk 26, into which frictional engagement it is forced by a coiled compression spring 2l lying between the gear 22 and a flange 28 of the pinion 2 I. By reason of the frictional engagement between the disk 26 and the gear 22, relative rotation is permitted between the pinion 2| and the gear 22, as may be required; but the friction is suiciently great so that it is normally adequate for driving the re-roll roller |2.

Loose on the shaft I8 of the re-roll roller is a spool 30, which has a frictional engagement on one side with a disk 3| fixed to said shaft I8. A coiled compression spring 32 on the other side of said spool 30, and lying between said spool and the pinion 23, maintains the frictional engagement between the spool 30 and the disk 3|. The spool 3U is light in weight, so that when its movement is stopped by the stop shoulder 34 its stoppage requires little force.

Within the groove of the spool 3l) is pivoted a stop-member 33, provided with a stop-shoulder 34 for cooperating with a pin 35 flxedly mounted in the frame-work of the meter. The stop-member 33, as shown, is of a general U-shape (Figs. 3 and 4), with its supporting pivot 33a at the base of the U and with one arm somewhat heavier than the other so that that heavier arm will move outward by centrifugal force if the rotation of the spool 30 is too rapid. That heavier arm, which is thus thrown outward by centrifugal force, is the one which carries the stop-shoulder 34.

In order to avoid the necessity for any spring for normally holding the stop member 33 retracted within the groove of the spool 30, the pin 35 is preferably located so that it will not be engaged by the stop-shoulder 34 if in the course of slow rotation of the spool 30 the heavier arm of the stop-member 33 drops out of the spoolgroove by gravity. To that end, the stop-pin 35 is desirably located, as illustrated in Figs. 3 and 4, slightly above the horizontal plane of the shaft |8 on that side of the spool 3|) which travels downward in the normal spring-driven movement of the re-roll roller I2.

In operation:

The spring I5 is Wound in the usual manner, by a key on the stem I6.

The spring I5 drives the re-roll roller I2 through the intervening gearing; which driving occurs with no normal slipping between the gear 22 and the disk 26.

If with the spring I5 wound or nearly wound the operator winds the re-rcll roller I2 backward, as by unrolling the re-rolled record chart to see what its showing was at some earlier time or over some earlier period, and thus moves the gear I'I backward to cause winding of the spring I5, no breakage occurs when and if the spring I5 reaches fully wound condition, because such slipping then occurs between the gear 22 and the disk 26 as may be necessary to accommodate the excess movement of the re-roll roller I2 after the Spring I5 is fully wound.

If for any reason the re-roll roller I2 starts to rotate forward too rapidly, or in the spring-unwinding direction, as because the record sheet breaks or the supply of record sheet is exhausted or the operator suddenly releases the unrolled record sheet, the excessive speed of rotation causes the heavier arm of the U-shaped stopmember to ily outward so that the stop-shoulder 34 will strike the pin 35. This stops the spool 3U abruptly. But the hammer-blow between the stop-shoulder 34 and the pin 35 is relatively light, because the frictional mounting of the spool 30 on the shaft I8 permits such shaft I8 and the re-roll roller and the parts geared thereto to be brought to a relatively gentle stop by reason of the slipping, usually for only a part of a revolution, between the spool 30 and the disk 3I. Thus the re-roll roller I2 is prevented from running away in the event it somehow gets free, but the mechanism is nevertheless guarded against undue shock.

I claim as my invention:

1. In a graphic meter, the combination of a re-roll roller, a driving spring therefor, a driving connection interconnecting said driving spring and said re-roll roller, a light-weight rotatable member frictionally interconnected with said reroll roller and provided with a centrifugally actuated part having a stop-shoulder, and a stoppin in a position to be engaged by said stopshoulder on centrifugal actuation of said centrifugally actuated part to stop said light-weight member and thereby after some slipping at the frictional connection between said light-weight member and the re-roll roller to cause a gentle stopping of the latter.

2. In a graphic meter, the combination of a re-rcll roller, a driving spring therefor, a driving connection interconnecting said driving spring and said re-roll roller, a light-weight rotatable member frictionally interconnected with said reroll roller and provided with a centrifugally actuated part having a stop-shoulder, a stop-pin in a position to be engaged by said stop-shoulder on centrifugal actuation of said centrifugally actuated part to stop said light-weight member and thereby after some slipping at the rctional connection between said light-weight member and the re-roll roller to cause a gentle stopping of the latter, said driving connection between the reroll roller and the spring including a frictional drive which permits slipping on reverse winding of the re-roll roller with the spring wound.

DONALD J. ANGUS.

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