US2474656A - Ratchet mechanism - Google Patents

Description

June 28, 1949. w. B. CLAUS 2,474,656

RATCHET MECHANISM I Filed Oct. 29, 1945 2 Sheets-Sheet 1 fzyvsnzaz" 'ZZ/alferfi. Claus MK NM Patented June 28, 1949 "'RATCHET MECHANISM Walter BnClaus, Van Nuys, .Califaassig'nor; by

mesne assignments, to Howe 8;. :Fant, Inc., South Norwalk, -Gnn., a corporation. ofiDelaware Application October 29, 1945, SerialNou625g257 4 Claims; (0134 -142) This invention has to do with a ratchet meche anism which. is capable of selectively moving a. driven member in either of two. opposite directions, depending upon the direction of initial actuation of the mechanism. The invention. is

especially useful and. has been designed particularly for a receiver in a telemetering system; and; although the invention is not limited to that particular use, it will be described in its present. preferred and illustrative form as for that use.

In telemetering systems such as that set out in. the application of Gabriel lVl'. Giannini, Ser; 597,459, filed June 4, 1945, and entitled Telemetric system, now Patent No. 2,471,947, a transmitter instrument generatesand delivers a series of spaced electrical pulses of a signxdependent upon the direction of actuation of the transmitter. The series of pulses is received by a re ceiver instrument, whose function 'is to move a driven member step by step in one direction or theopposite direction, depending upon the sign on the. received pulses. The receiver, in effect, algebraically adds the received pulses and operates its driven-member accordingly; That driven member may actuate an indicator, or it may actuate; a device or mechanism which is remotely controlled from. the transmitter.

The general purpose and object of thepresentinvention is to provide a-two-way ratchet mechanism, especially adapted for use in aatelemetric receivenand which is capable of dependable actuation "by" polarized electrical impulses of small magnitude, short; duration and rapid succession.

The present preferred forms of the invention will be explained in illustrative detail in the following detailed description, reference being had: to the accompanying drawings in which Fig." 1 is a diagrammaticperspectiveillustrating essentials of my invention; 2. is a plan section of a developed form 0 the invention, taken as indicated by line Z-2.. on.Fig.3;

Fig. 3 is a central vertical section taken as indicated by line 3 3 on 2, with certain parts in eleyatiom.

Fig. 4 is a fragnientary section on line 4! Fig.3; and

Fig. 5 is an elevation of the mechanism, the view being taken in an aspect from. thef'right on Fig. 3,

' Figs. 2.'and"3j are toascale approximately five titties the linear dimensions of an actual device, andFigs. 4 and 5 are on a smaller scale.

"Referring first to Fig. 1, an. actuating slia'ft is shown at IU, carrying a 0011' I I which islocated in a magnetic field diagrammatically. indicated bythe arrows i2; The relation of thecoiltothe magnetic field is. such. that; current flowing through thecoil in one direction will cause an.-

gular movement of the shaft in a predetermined direction of rotation, while current flowing in the" opposite-direction through thecoil will cause rotation of the shaft through an angle in .the opposite direction. The electro-magnetic means for rotating shaft IE1 in opposite directions. by electrical pulses of opposite signs may be of a nature. different from. that of the movingcoil type which I here describe. For instance, in the mentioned Giannini application a receiver is shown as actuated by a driver which has .amow ing magnet. I make no claim herein toeither type ofdriver, in and of itself.

In my ratchet, mechanism as here illustrated, a double ended arm I3 is fixed on shaft Lend a. pawl I4 is pivoted to each of the twoends of the arm. 'Pawls M are shown here as essentially straight rods or bars and normally in substantial parallelism with each other; As shaft Ill and arm I3 swing in either clockwise or counter-clockwise direction one pawl M. moves upwardly in Fig. l, and the other pawimoves downwardly. The two pawls are guided b suitable guide stops, here shown. as stationary pins l5, against which. the pawls are pressed by two springs l6.

Fig. 1 illustrates the normal positionof the mechanism, which it assumes when at rest. Arm I3. and pawls M and actuating coil 6 l arehel'd in thisinormal position by a pair of centering springs H which are shown in Fig. 1 asyieldingly holding-a pin l-Bhetween their free ends; Pin {8 is set in arm 13, and in the normal contered position, the springs may engage shaft l0 as Well aspin it. Such. an arrangement serves to reduce elastic resonant vibration of the parts about the centerednormal position. From Fig; 1 it will be noted that thewhole mechanism in its central-.normalposition is symmetrically ar-- ranged with reference to-a vertical plane passing through the axis of shaft Iii; Ratchet wheel 20 is mountedon. an. aXisZl located in that plane and parallelto the axis of shaft ill. Thus, the mechanism .asillustrated in Fig. 1, is symmetric with relation to a, plane determined by axis ill. of ratchet 20. and the axis of shaft As shown. in Fig. .l pawls it project ,from arm it! toward theratchet 253, andinthe, normal position. the free ends. Mwof thepawls liev under two teeth; of the. ratchet, but preferably not in.

immediate contact with them. In the preferred form of the mechanism as here shown, the two particular teeth 2601, are not diametrically opposed to each other, but are separated by a chordal distance (in Fig. 1 this chordal distance is horizontal) which is substantially less than the diameter of the ratchet wheel. The straight two pawls M are so spaced and guided by pins 85 that the horizontal distance between their two free ends is also less than the diameter of the ratchet wheel. That horizontal spacing of the two pawls is such that their upper free ends, lying under the two particular teeth 28a, clear the next two teeth 26b which lie just below the two teeth in. In other words, using pawls which are simple straight bars, those pawls extend and have their guided movements along lines which are non-tangential to the toothed periphery of the ratchet wheel. It is not necessary that the pawls be in substantial parallelism; but that is a simple and effective arrangement of the two straight pawls.

The ratchet wheel is yieldingly held in the relative normal position shown in Fig. 1 by a spring detent, such as that illustrated at engaging a space between teeth of the ratchet.

If we now assume that shaft iii and arm 53 are swung in a clockwise direction, then the left hand ratchet Ma will move up into engagement with the left hand tooth 29a, and further movement will then move ratchet 29 in a clockwise direction. In its preferred form the mechanism is designed to move ratchet Zll through only the distance of one tooth on each actuation, and stops are preferably provided as will be later explained, to limit the swinging of arm it. During the upward movement of the left hand pawl, the right hand pawl I4 moves downwardly through a distance substantially equal to the distance of the upward movement of the left hand pawl; and in moving downwardly, the right hand pawl moves away from the ratchet, so that the right hand tooth 2th will clear the end of the right hand pawl as the ratchet wheel rotates. During the upward movement of the left hand pawl, the left hand tooth 2% may come into engagement with that pawl; but if it does so, it merely pushes that pawl slightly outwardly against the light pressure of spring it, but does not push that pawl outwardly far enough to move its end out of engagement with the left hand tooth Ella. On return movement of the pawls to normal position, the left hand pawl drags down over left hand tooth 2th and then is sprung in under it; the right hand pawl moves upwardly, guided by pin If: to clear the right hand tooth 28a which has now taken the position previously occupied by tooth Zilb.

On cessation of the force which has swung shaft ill clockwise, the centering springs ll immediately return the pawl mechanism to normal position, and leaving ratchet wheel 2% in its advanced position. The whole mechanism then again. stands in the position illustrated in Fig. 1, ready for a subsequent actuation. If that subsequent actuation is in an opposite direction, swinging shaft Ill counter-clockwise in Fig. l, the right hand pawl M then acts to engage the right hand teeth 29a to rotate ratchet 2!? through one step in a counterclockwise direction.

The whole mechanism illustrated in Fig. l is capable of being designed into a very small instrument and with its moving parts having very low inertias. The instrument is therefore capable of rapid successions of actuation by very small pulses of short duration. Figs. 2 and following show a preferred design development of such an instrument.

In Figs. 2 and following the actuating coil is shown at lib, mounted on a shaft 55, which is journaled at its upper and lower ends in bearings in a frame plate 52 and in a bracket member 53 which forms a part of the framing of the instrument. I may remark that, as shown in Figs. 2 to 5, the instrument is shown with coil shaft 5| in a vertical position with a ratchet mechanism in a horizontal plane, merely for convenience of illustration. The instrument in use may assume any relative orientation. Coil 50 rotates in a gap between two magnetic pole pieces 55 and a central core 5?, core 56 being mounted on the bracket member Pole pieces 55 form the poles of a magnetic circuit which includes two permanent magnets 5"! and a yoke 58. The coil normally stands in the relative position shown in Fig. 4 when the ratchet mechanism is in its normal inactive position such as shown in Fig. 2. Connections to the coil are made in any suitable manner, as through the spiral connectors 59 shown in the drawings.

As shown in Figs. 2 and 3, the pawl carrying arm tit is mounted on shaft 51 above coil 50 The upper face of arm 6% is provided with a central flat block 6i which is yieldingly confined between the two centering springs 62, whose fixed ends are set in an upper extension 53a of frame member The elastic pressures of these springs on block 6| may be suitably adjusted by the adjustment screws shown at '53 in Figs. 2 and 3. Suitable stops for the swinging motion of pawl arm W are provided by the stop pins shown at 64 in Figs. 2 and 3. These stop pins may be conveniently mounted for adjustment as shown in the drawings, being eccentric projections from screws 6 5 which are rotatably set in upper frame plate 52.

The two ratchet pawls are shown at 70, pivoted to the ends of arm- 60 and extending their free ends, in substantial parallelism, toward the toothed ratchet wheel ll, which is mounted on shaft l2, that shaft being shown as journaled in bearings in upper frame plate 52 and in a lower frame plate 13 which also forms a part of the framing of the instrument. As here shown, shaft 12 may also carry a pinion M meshing with a larger gear 15 on a shaft 16. An extension ll of that shaft may, for instance, carry an indicating pointer which moves over a calibrated dial. Or shaft 11 may be connected to any instrument, de-

vice or mechanism which is to be remotely controlled.

Adjustable guides for pawl '10 are shown in the form of pins all which are eccentrically carried by rotatable screws 8| set in the upper frame plate 52. Springs 83 lightly press pawls 10 against guide pins 80. The fixed ends of those springs are secured at 84 to a part of the stationary frame; and pressure exerted by the springs may be adjusted by eccentric pins 85 which are mounted on rotatable screws 86 set in upper plate 52. Extensions 83a of springs 83 serve as detents to engage between teeth of ratchet gear II to hold it releasably in normal position.

The general relationship of the several parts, and their functions, is the same as is shown in Fig. 1 and as has been described for that figure. In the specific design of Fig. 2 it will be noted that the parts of the ratchet mechanism, in normal inactive positions, are symmetrically arranged with reference to a plane determined by the axes of shafts 5| and 12. The two pawls l0 lie and move in substantial parallelism, and their ends lie adjacent two teeth Ha of ratchet wheel II and normally clear the two teeth Mb.

I claim:

1. A ratchet mechanism comprising a rotatable toothed wheel, a pawl carrying arm pivoted centrally on an axis parallel to the axis of rotation of the wheel and located to one side of the wheel, a pair of pawls pivoted to the opposite ends of the arm, the pawls extending parallel and substantially tangent to the wheel and with their free ends lying close to respective teeth on the wheel, when the arm is at rest and lies normal to a line connecting the axes of the wheel and arm, and means engaging the pawls between their ends and guiding the pawls to move nontangentially to the wheel, as the arm is swung on its pivot.

2. A ratchet mechanism comprising a rotatable toothed wheel, a pawl carrying arm pivoted centrally on an axis parallel to the axis of rotation of the wheel and located to one side of the wheel, a pair of pawls pivoted to the opposite ends of the arm, the pawls extending parallel and substantially tangent to the wheel and with their free ends lying close to respective teeth on the wheel, when the arm is at rest and lies normal to a line connecting the axes of the wheel and arm, and means engaging the pawls between their ends and guiding the pawls to move non-tangentially to the wheel, as the arm is swung on its pivot, said means including guide stops limiting inward movement of the pawls toward one another and yielding means pressing the pawls against the stops.

3. A ratchet mechanism comprising a rotatable toothed wheel, a pawl carrying arm pivoted centrally on an axis parallel to the axis of rotation of the wheel and located to one side of the wheel, a pair of pawls having the form of substantially straight bars pivoted to the opposite ends of the arm, the pawls extending parallel and substantially tangent to the Wheel and with their free ends lying close to respective teeth on the wheel, when the arm is at rest and lies normal to a line connecting the axes of the wheel and arm, and means engaging the pawls between their ends and guiding the pawls to move non-tangentially to the wheel as the arm is swung on its pivot.

4. A telemetric receiver mechanism comprising a ratchet mechanism which includes a rotatable toothed wheel, a pawl carrying arm pivoted centrally on an axis parallel to the axis of rotation of the wheel and located to one side of the wheel, a pair of pawls pivoted to the opposite ends of the arm, the pawls extending parallel and substantially tangent to the wheel and with their free ends lying close to respective teeth on the wheel, when the arm is at rest and lies normal to a line connecting the axes of the wheel and arm, and means engaging the pawls between their ends and guiding the pawls to move non-tangentially to the wheel, as the arm is swung on its pivot, and electro-magnetic means adapted selectively to swing the pawl arm in either direction from its normal position.

WALTER B. CLAUS.

REFERENCES CITED The following referentces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 793,389 McBerty et al June 27, 1905 2,201,004 Chandler et al. May 14, 1940 2,400,088 Hayslett et a1. May 14, 1946

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