US3250468A - Resettable odometer - Google Patents

Description

May 10, 1966 P. L. POWELL RESETTABLE ODOMETER Original Filed Jail. '7, 1965 Parrvck L Pan e,

A r /arnc/ United States Patent 3,250,468 RESETTABLE ODOMETER Patrick L. Powell, Franklin Park, IlL, assignor to Stewart- Wamer Corporation, Chicago, L, a corporation of Virginia Continuation of application Ser. No. 249,633, Jan. 7, 1963. This application Sept. 28, 1964, Ser. No. 419,260

2 Claims. (Cl. 235-139) This invention is a continuation of application Serial No. 249,633, filed January 7, 1963, now abandoned and relates to a resettable odometer of the type used for recording trip mileage including a series of intermittently rotating dials or dial cylinders, and more particularly, to an arrangement for insuring the exact alignment of the numbers on the cylinders as the odometer is cycling to record mileage.

In general use today are odometer structures consisting of a series of dial cylinders carrying numbers, with the cylinders positioned coaxially upon a single shaft for rotation about the shaft axis to display a constantly changing series of numbers indicative of the mileage occurring during the travel of the vehicle. The numbers, therefore, may represent units, tens, hundreds, and thousands of miles for example, and in which the input drive means associated with the units dial causes continuous rotation of this dial and intermittent rotation of the succeeding dials in the series through the use of transfer gears connecting adjacent dial members.

In the past, however, great difiiculty has been experienced in maintaining the figures on the odometer dial cylinders in correct alignment and preventing their creep. The ditficulty in maintaining correct alignment of the odometer cylinders results from a variation in the frictional forces occurring as a result of the motion transfer between the cylinders since the motion imparted to the units cylinder is transferred through the intermediate tens and hundreds cylinders to the thousands cylinder only once for every one hundred revolutions of the units cylinder. It is readily apparent that the motion transfer means between the units cylinder and the tens cylinder is under much greater load than the motion transfer means between the hundreds cylinder and the thousands cylinder, while the motion transfer means between the tens cylinder and the hundreds cylinder is under less load than the motion transfer means between the units cylinder and the tens cylinder but under somewhat greater load than the motion transfer means between the hundreds cylinder and the thousands cylinder.

The heavy load imposed upon the motion transfer means connecting the units cylinder and the tens cylinder may be sufficient to disengage the drive means between these two cylinders and, in fact, may result in a failure to incrementally rotate any or all of the cylinders or only partially so.

It is, therefore, a primary object of this invention to provide an improved odometer including a series of rotatable dials having means to insure exact alignment of the numbers on each of the dials during all phases of operaconstruction and economical to manufacture.

Further objects of thisinvention will be pointed out in "ice the following detailed description and claims and illustrated in the accompanying drawing which discloses, by way of example, the principle of this invention and the best mode which has been contemplated of applying that principle.

In the drawing:

FIGURE 1 is a front elevational view of the improved odometer of the present invention;

FIGURE 2 is a side view, partially in section, of the device of FIGURE 1 taken along lines 22;

FIGURE 3 is an exploded, perspective view of a portion of the apparatus of FIGURE 1 showing the connection between the input drive means and the unit dial cylinder;

FIGURE 4 is an exploded, perspective view of the elements forming the units and tens dial cylinders and the motion transfer means associated with both cylinders.

In general, the apparatus of this invention comprises an odometer including a central shaft having a series of dials positioned on the shaft for independent rotation about the axis thereof. Internal gear teeth are formed on opposite sides of each of the dials with the sides opposite the input drive means having mutilated teeth to effect partial rotation of the next succeeding dial while the side closest to the input drive means of each dial includes continuous gear teeth. Between each pair of dials is provided a motion transfer means in the form of a pinion which is spring biased to engage respective gear teeth of the adjacent dials to effect sequential, intermittent drive of the dials in response to input rotation of the unit dial of the series. The present invention resides in means for effecting greater bias of the pinion contacting the dial associated with the input drive, whereby the pinion associated with the input wheel is maintained in engagement with' its respective dials regardless of the load created by the simultaneous movement of the other dials in the series, as occurs during incremental movement of the thousands dial.

Referring to the drawing, the odometer of the present invention, which is indicated generally at 10, includes a central drive shaft 12 which acts to support a series of dials or dial cylinders which may rotate independently and which may be designated from right to left respectively as units dial 14, tens dial 16, hundreds dial 18, and thousands dial 20. The dials are cylindrical in form and may be constructed from any suitable material, such as plastic, with the numerals 22, etc., formed integrally therein or aflixed thereto, such as by painting on the outer peripheral surface. The dials 14, 16, 18 and 20 are slideably positioned upon shaft 12 and are adapted for free rotation with respect to each other and about the shaft 12. The inner or units dial 14 is adapted to be driven by a gear ratchet and bushing assembly 24, which may be best seen in FIGURE 3. Bushing member 26 is also mounted for free rotation on shaft 12 and is fixedly attached to the input drive gear 28 on one side of the bushing 26. The bushing 26 is undercut at its opposite face and provided with a reduced cross-sectional portion 30 having a flattened edge 32. A ratchet member 34 formed of spring metal has a central aperture 36 with a flattened locating surface 38 allowing the ratchet member 34 to be fixedly positioned on bushing 26 by means of locating surfaces 32. Washer member 40 acts to prevent axial movement of ratchet member 34 away from bushing 26.

The free ends of the ratchet member form lugs 42 which engage the internal teeth 44 of the units dial 14. In this manner, counterclockwise rotation of the input gear 28, as viewed in FIGURE 2, causes a like counterclockwise rotation of the units dial 14 about the axis of shaft 12. Thus, in this case, the right-hand number dial Patented May 10, 1966 used for illustrative purposes only to allow proper description of the invention.

It can be seen in FIGURE 3 that shaft 12 has a longitudinal groove 46 runningalong the periphery thereof.

The groove 46 cooperates with a tab spring 48 which frictionally grips an internal flange 50 associated with each numbered dial. The axle 12 projects through the internal flange 50 to allow the dials to be reset to zero by rotating axle 12 in a direction opposite that of the normal drive cycle allowing the ratchet members 42 to slip over the associated teeth 44 whereby inwardly directed tab portion 52 of spring 48 falls within groove 46 to cause the dial to then rotate with the axle, to a position where all of the dials 14, 1 6, 18 and 20 have their like numerals uniformly aligned. A tine 53 is provided on the end of annular spring 48 opposite the tongue or tab 52. Tine 53 has a major cross-sectional dimension transverse to the radial dimension of the dial for engaging a recess 53a in the radial web of the dial. This firmly and securely seats the annular spring 48 in position with the maximum ease of assembly.

Between each of the numbered dials is a pinion bracket 54, which may be best seen in FIGURE 4, of somewhat irregular configuration although circular in form. The pinion bracket 54 is formed from thin sheet metal stock and includes a central aperture 56 allowing the bracket to be loosely positioned upon shaft 12. A pair of extension portions 60, carrying central slots 62, allow the individual pinion bracket 54 to be positioned on the shaft 12 but prevent it from rotation thereabout during operation of the device. Intermediate of extensions 60 is a pair of generally parallel, radial extension portions 64 forming slot 66 therebetween for receiving a small pinion gear 68. The pinion gear 68 is generally cylindrical and includes a circumferential groove 70 forming an internal reduced cross-sectional portion which is of approximately the same diameter as the width of the slot 66. The pinion 68 is received by the slot 66 in such a manner that the pinion 68 is free to rotate about its own axis within the slot. With the pinion bracket 54 positioned between respective dial cylinders, the pinion 68 is adapted to contact respective inner peripheral portions formed in the sides of the dials.

To accomplish this, the apparatus of the present invention advantageously makes use of a curved spring member such as 72, FIGURE 4, which is associated with pinion 68 acting to couple dial 16 and the next adjacent dial 18 to the left (not shown). The curved spring 72, has a pair of spaced, elongated slots 74 which are approximately equal in length to the width of the tab or extension portions 64 allowing spring member 72 to be positioned thereon with the ends 76 of the spring members contacting the relatively flat portion 78 of the pinion bracket to exert an upward biasing force on the pinion 68 tending to press it against the inner peripheral surfaces of respective dial members.

As mentioned previously, each of the cylindrical dial members 14 are of identical configuration and include recessed sides. As indicated in FIGURES 1 and 2, the right-hand side of dial 14 includes a series of spaced, internal teeth 44, in this case, numbering twenty, which are evenly distributed about the inner peripheral surface of dial 14. On the opposite side of dial 1 4, as indicated in FIGURE 3, the left side is recessed and includes an 4 annular ridge 80 which is discontinued only at one point to form a gap 82 which is approximately one tooth in width. Adjacent the edge of the ridge portion 80 are formed a pair of teeth members 84 which project longitudinally of the dial member toward the open face thereof. The tooth members 84 are also spaced a distance of approximately one tooth. Co-operating with these internal teeth formed on the respective dial members are the teeth of pinion members 68. One side of the pinion 68 carries three teeth which ride on the inner surface 88 of ridge 80 and effect incremental rotation of the pinion 68 as they fall into the gap 82. In between the respective radially projecting teeth 86 are formed three additional teeth which do not project longitudinally of the slot 70 to the extent teeth 86 do, and these act in conjunction with the circumferentially displaced teeth 86 to effect rotation of the pinion as they contact the spaced teeth 84 formed on the inner surface of the respective dial members adjacent the raised portion of ridge 80.

On the opposite side of the pinion member 68, there are formed six equally spaced teeth 92 which are in mesh with the internal teeth 44 of the next adjacent dial to the left of the pinion, such as dial 18 in FIGURE 1. Since there are twenty such teeth 44, a one-third revolution of pinion 68 on bracket 54 will rotate the next left-most dial two teeth or one-tenth of a revolution. It is apparent, therefore, that in the operation of the device, input rotation of drive gear 28 for one revolution will cause dial 14 to revolve in like manner a complete revolution due to the inner engagement of spring tabs 42 and gear teeth 44 of this member. One rotation of the units dial 14 will cause the pinion member 68, which during most of the rotation of dial 14 is sliding along the surface 88 of ridge 88, to effect a one-third revolution about its own axis at the point where tooth 86 falls off the ridge surface 88 into gap 82. Since two of the teeth 86 are riding upon the surface 88 of ridge 80 during most of the rotation of the respective dial, and since the spring 72 associated therewith tends to insure engagement between the pinion 68 and the respective dial members, the pinion is prevented from rotating except at the point where teeth 86 fall within slot 82 and teeth 90 rotate about longitudinally spaced teeth 84.

It is important to note that the force of spring 72 must keep the pinion in engagement with teeth 84 as the teeth 84 pass the pinion so as to index the pinion one-third of a revolution and drive the next succeeding dial of the series to the left, one-tenth of.a revolution. If this spring force is not great enough to drive'the next succeeding dial, the pinion will tend to drop in its slot 66 against the bias of the spring 72 to the extent where it may become disengaged with teeth 44 and the next succeeding dial and thereby effect possible misalignment between the num bers on the dial as well as fail to properly rotate the next succeeding left-hand dial in the desired incremental manner. i

The load on the spring 72a between the right-most dials, that is, the dial associated with the input drive becomes the greatest when the mileage is changing from one hundred digit to the thousand digit dial. For example, during a change from 2999 to 3000, the force exerted by the drive gear 28 must be directed successively through dials 14, 16 and 18 and their associated intermediate motion transfer members in the forms of pinions 68 to the outermost dial 20. In this respect, the spring member 7211 associated with the pinion 68a between dials 14 and 16 must carry the load of the three left-most dials and the force that is created by the springs and pinion in between these dials. In like manner, the spring 72 associated with pinion 68 between the tens dial'16 and the hundreds dial 18 must carry more of a load than the spring (not shown) associated with the pinion between dials 18 and 20. If the spring forces are equal and relatively light, it is apparent that slippage may readily occur between the units and tens dials 14 and 16 since the frictional force transferred between these two members is the greatest.

In order to prevent possible slippage between respective dial members, and more particularly between these dial members closest to the input force during the moments when all of the dials are rotating simultaneously, the device of the present invention is advantageously provided with spring members associated with each of the pinion elements 68, 68a, etc., having varying spring constants to insure continued meshing of the pinions with their respective dials. In this manner, since the right-hand spring 72a associated with the pinion bracket 54 positioned between dials 14 and 16 has to overcome all the forces created by the two springs to the left, the right-most spring 72a is made substantially heavier than the other two so as to enable it to maintain its pinion 68a in proper engagement in spite of the load created by the other two springs. If necessary, the spring member 72 associated with pinion bracket 54 positioned between dials 16 and 18 may be heavier than the spring associated with the lastmost pinion 68 but not'quite as heavy as the spring 72a associated with the right-most pinion between dials 14 and 16.

As an example, in an odometer used in a commercial vehicle the right-hand spring is apporximately .006 inch thick formed of steel spring stock as compared to .005 inch for the other two springs. This gives the spring a resilient force or spring constant of about 1.25 times that of each of the other springs. This amount, however, is not as critical as it may appear, although if the force is too great, such as being more than twice that of the weaker spring, too much friction is introduced by exces sive biasing of a pinion towards its respective internal gears formed on respective dial members 14 and 16. While spring member 72 is formed, as is shown, as a curved leaf spring, it is not the intention to be limited to such a configuration. A conventional coil spring may be positioned within slot 66 between the pinion 68 and the respective dial members, the only necessity being that the biasing force of the springs vary such as by varying the stiffness from more stiff to less stiff in a direction away from the input force tending to rotate the odometer dials.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and detail of the device illustrated and its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore to be limited only as indicated by the scope of the following claims. T

What is claimed is:

1. A resettable odometer comprising a shaft, a plurality of dial cylinders carried on said shaft with each cylinder assigned a respective digit order and rotated for indicating respective digit values in each order, means for rotating each dial cylinder in one direction in response to the rotation of one of said dial cylinders, a hub on each dial cylinder having a slot therein communicating between the outer periphery of said hub and said shaft, each cylinder having a recess adjacent the respective hub, said shaft having a groove formed in its periphery defining adjacent transverse walls parallel to the axis of said shaft and traversing each dial cylinder, a split annular ring of uniform thickness in direct encircling engagement with the outer surface of each hub with each spring having a tine at one end engaging said cylinder recess with a major cross-sectional dimension of said tine transverse to the radial dimension of said dial cylinder, and a tongue on the other end of said spring extending through the respective slot for engagement with one wall of said shaft groove in response to rotation of said shaft in one direction to rotate all of said dial cylinders simultaneously for resetting said dial cylinders to a desired position and moving through said slot transversely to the other wall of said groove to enable said dial cylinders to rotate in said one direction independently of said shaft in response to the movesigned the lowest digit order being rotated from an eX-.

ternal source, radially inwardly directed gear teeth on opposite sides of each dial cylinder for respectively receiving and transmitting motion to and from the respective dial cylinder, a pinion located between successive dial cylinders at a position between the periphery of the adjacent cylinders and said shaft and having teeth with non-linear curved surfaces thereon cooperating with the inwardly directed gear teeth on each of the adjacent dial cylinders for intermittently transmitting motion from an adjacent lower digit order dial cylinder to the adjacent higher digit order dial cylinder in response to the adjacent lower digit order dial cylinder being rotated in one direction from said source independently of said. shaft to a predetermined position whereby each of said higher digit order dial cylinders are intermittently rotated simultaneously with the lower digit order cylinder independently of said shaft for indicating digit values in the respective digit order, means enabling said pinions to move radially inwardly of said cylinders to disengage from the adjacent gear teeth, a tab spring for each cylinder fixed to the respective cylinder against angular movement relative the respective cylinder and encircling said shaft with a tongue on each tab spring biased against said shaft to ride said shaft during rotation of said cylinders independently of said shaft and engage against one wall of said groove in response to rotation of said shaft in one direction for creating a force against said dial cylinders, said force being eifective through said gear teeth for moving said pinions radially inwardly to disengage said pinions from said gear teeth and enable rotation of said tab springs and cylinders in said one direction by said shaft for displaying a common digit valueQand a pinion spring of uniform crosssection of each pinion of bias the respective pinion radially outwardly for normally engaging the adjacent cylinder gear teeth, the pinion spring associated with the lowest digit order pinion being of thicker stock than each other pinion spring to provide a spring constant for the lowest digit order pinion spring of greater value than each other pinion spring whereby said lowest digit order pinion spring supplies a radially outwardly directed biasing force greater than the radially inwardly directed load created by the other pinion springs and tab springs on the lowest digit order pinion during simultaneous rotation of all of said cylinders independently of said shaft to prevent disengagement of said lowest digit order pinion from its adjacent gear teeth.

References Cited by the Examiner UNITED STATES PATENTS 1,492,362 4/ 1924 Dorsey 235--144 1,493,087 5/ 1924 Toney 235-144 2,087,093 7/1937 Marquart 235144 2,131,622 9/1938 Helgeby 235144 2,550,950 5/1951 Young 2351.3 X 2,658,685 11/1953 Harada 235139.1 2,737,345 3/ 6 Harada 2351.3 2,858,986 11/1958 Hoffman 235-114 LEO SMILOW, Primary Examiner.

C. G. COVELL, Assistant Examiner.

Claims (1)

1. A RESETTABLE ODOMETER COMPRISING A SHAFT, A PLURALITY OF DIAL CYLINDERS CARRIED ON SAID SHAFT WITH EACH CYLINDER ASSIGNED A RESPECTIVE DIGIT ORDER AND ROTATED FOR INDICATING RESPECTIVE DIGIT VALUES IN EACH ORDER, MEANS FOR ROTATING EACH DIAL CYLINDER IN ONE DIRECTION IN RESPONSE TO THE ROTATION OF ONE OF SAID DIAL CYLINDERS, A HUB ON EACH DIAL CYLINDER HAVING A SLOT THEREIN COMMUNICATING BETWEEN THE OUTER PERIPHERY OF SAID HUB AND SAID SHAFT, EACH CYLINDER HAVING A RECESS ADJACENT THE RESPECTIVE HUB, SAID SHAFT HAVING A GROOVE FORMED IN ITS PERIPHERY DEFINING ADJACENT TRANSVERSE WALLS PARALLEL TO THE AXIS OF SAID SHAFT AND TRAVERSING EACH DIAL CYLINDER, A SPLIT ANNULAR RING OF UNIFORM THICKNESS IN DIRECT ENCIRCLING ENGAGEMENT WITH THE OUTER SURFACE OF EACH

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