US3907198A - Resettable counter - Google Patents

Abstract

A drive shaft drives a counter wheel system through a gear coupling device with the aid of a step-up drive between the drive shaft and the coupling device and a step-down drive between the coupling device and the counter wheel system. Advantageously, the step-down drive has a transmission ratio which is the inverse of the transmission ratio of the step-up drive.

Description

United States Patent Kelch et a1.

[ Sept. 23, 1975 RESETTABLE COUNTER Inventors: Heinz Kelch, Martinsweiler 191, D 7741 Buchenberg; Helmut Muller, Martin-Luther-Str. 2, D 7742 St. Georgen, both of Germany Filed: Apr. 11, 1974 Appl. No.1 460,068

Foreign Application Priority Data Apr. 17. 1973 Germany 2319369 US. Cl. 235/144 DM Int. Cl G06c 15/42 Field of Search. 235/144 R, 144 EA, 144 DM, 235/144 D, 144 M, 144 SS, 144 SM, 144 SP [56] 7 References Cited UNITED STATES PATENTS 979,437 12/1910 Cornine 235/144 DM 1,477,536 12/1923 Breitling 1 235/144 EA 2,081,693 5/1937 Ashley 235/144 DM Primary ExaminerLawrence R. Franklin [5 7] ABSTRACT A drive shaft drives a counter wheel system through a gear coupling device with the aid of a step-up drive between the drive shaft and the coupling device and a step-down drive between the coupling device and the counter wheel system. Advantageously, the step-down drive has a transmission ratio which is the inverse of the transmission ratio of thc step-up drive.

7 Claims, 3 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of2 3,907,198

FIG.1

US Patent Sept. 23,1975 Sheet 2 of2 3,907,198

I 1 RESETTABLE-CQUNTER' 4.

BACKGROUND OFTI IE INVENTION N This invention relates to counters which can be reset, for example to zero, after a countings'operation; Such counters have been used particularly in fluid meters. They have been subject to the problem that a considerable counting error is caused by -the .recoupling of the gear coupling device pursuant to each uncoupling and resetting operation.

For many counters of the indicated type an approval by public or industrial offices is necessary, and in many cases such approval is forthcoming only if metering inaccuracies are kept at a level of less than one fivehundredth of the circumferenceof the counter'wheel of lowest order. At the same time of course it is necessary to manufacture the counters as inexpensive as possible and therefore to'refrain from any use of complex and expensive mechanisms, such as roller type clutches.

Rather, it is usual to effect coupling and uncoupling of the drive, for resetting, by the use of releasably meshing spur gears, which form part of a more comprehensive spur gear drive system. Such gear coupling devices have a recoupling error of up to one-half of a tooth. Therefore, recoupling errors of up to one twohundredth of the input counter wheel periphery can be encountered with the usual gears if this input counter wheel is conveniently driven by a gear of about I teeth (corresponding to about 100 graduations on the periphery of the input roller) and if the driving gear of the gear coupling has a similar number of teeth, as is generally desired. Evidently the recoupling error of one two-hundredth of the input wheel periphery is entirely too large in many cases. It can lead to non-approval of the counter by the calibrating officers or similar authorities if exacting standards are enforced.

SUMMARY OF THE INVENTION It is an object of the invention to avoid the aforementioned difficulties and problems of earlier resettable counters.

Another object is to provide a resettable counter which can be recoupled, persuant to uncoupling for resetting, with a recoupling error of considerably less than one two-hundredth of the input counter wheel pe riphery.

A further object is to provide such a counter which at the same time can be constructed simply and inexpensively.

For these purposes the invention provides a gear coupling device for a resettable counter with a step-up drive (that is a speed-up transmission) for driving one of the coupling gears and with a step-down drive (that is a speed reducing transmission) driven by the second coupling gear. Advantageously, the step-up transmission uses a speed-up ratio of approximately I to 4 and the reduction gearing which follows uses a speed reduction ratio of 4 to I. These ratios are available simply and inexpensively by means of a single pair of gears in the step-up drive and another similar pair in the stepdown drive. The recoupling error can thus be reduced conveniently to one eight-hundredth of the circumference of the input counter roller, which is within the tolerances of typical calibrating standards.

The novel features which are considered as characteristic for the invention are set forth in particular in the a pended claims. "The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTIONOF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTS A shaft 1 is driven, for example, by a fluid-flow respon'sive device such as a flow meter (not shown). Rigidly mounted on shaft 1 is a spur gear 2 which accordingly rotates in a plane normal to shaft 1. Gear 2 according to the invention constantly meshes with a pinion 3 and continuously drives this pinion so long as the flow meter and shaft 1 rotate.

Pinion 3 is pivoted to a lever 4 which can rock on shaft 1. A spring 5 biases this lever 4 toward the left, as viewed in FIG. 1, against a stop 6. A pivot 7, pivoted to lever 4 and rigid with pinion 3, is also rigid with a coupling spur gear 8, which in turn normally meshes with a second coupling spur gear 9, the coupling gears 8 and 9 being advantageously larger than pinion 3 and being of uniform size. A shaft 10, rigid with the second coupling gear 9, is also rigid with a pinion 11 which in turn meshes with drive gear 12 of the input counter roller 13 of the counter, this gear 12 being four times larger than its drive pinion 11. Thus, according to the invention, gears 2 and 3 provide a step-up drive ahead of gear coupling 8 and 9, whereas the gears 11 and 12 provide inverse step-down speed conversion.

By means of the resulting relatively rapid rotation of the gear coupling device 8, 9, the recoupling error of up to one-half of a gear tooth, existing at the coupling point between gears 8 and 9, is in effect reduced to a quarter of its value, that is to one-eighth of a tooth of gear 12 upon the speed reduction by the step-down drive 11, 12. Thus, the above-mentioned typical tolerance of about one five-hundredth of the periphery of gear 12 is now exceeded by the new gear drive system. At the same time, the system is simple and inexpensive to build, using the illustrated spur gears 2, 3; 8, 9; and ll, 12, all rigid with and normal to their respective shafts.

For resetting the new counter, lever 4 with coupling gear 8 is moved towards the right as shown by arrow 6a in FIGS. 1 and 2. This movement causes uncoupling of coupling gears 8 and 9. Also, if desired, the uncoupling movement of gear 8 may be limited by a brake roll 14. The movement of lever 4 and gear 8 can be effected manually or by any desired mechanism (not shown).

As shown in FIG. 3, coupling gears 8 and 9 can have the crowns of their teeth provided with bevelled extensions 15, 16. It will be appreciated that these extensions provide a cam action between any one tooth of driving coupling gear 8 and a tooth of driven coupling gear 9 which may happen to be positioned opposite the driving tooth at the moment of recoupling. In this way, meshing of the gear coupling apparatus can be achieved without interference or blocking of the teeth regardless of the exact relative positions of the gear teeth.

lt will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the one described above. 7

While the invention has been illustrated and described as embodied in a resettable counter, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications 'without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

I. A resettable counter comprising counter wheel means; drive means for driving the counter wheel means; gear coupling means between said drive means and said counter wheel means movable between an engaged position for driving said counter wheel means by said drive means and a disengaged position for allowing resetting said counter wheel means; a step-up drive between said drive means and said gear coupling means; and a step-down drive between said gear coupling means and said counter wheel means to minimize errors caused by reengagement of said gear coupling means after the latter has been disengaged for resetting said counter wheel means. i

2. A counter as defined in claim 1 wherein said stepup and step-down drives are gear drives.

3. A counter asdefined in claim 2 wherein said drive means comprises a shaft and said gear drive and gear coupling means comprise spur gears in planes normal to said shaft.

4. A counter as defined in claim 1, including means for yieldably holding said gear coupling means in coupled condition.

5. A counter as defined in claim 1, wherein said gear coupling means comprises a pair of spur gears having bevelled extensions on their tooth faces to facilitate said reengagement.

6. A counter as defined in claim 1 wherein said stepdown drive has a transmission ratio which is the inverse of the transmission ratio of said step-up drive.

7. A counter as defined in claim 1 wherein said drive means comprises a first spur gear arranged for continuous rotation; said gear coupling means comprising two spur gears in a plane parallel to said first spur gear; and including a lever pivotable about the axis of said first spur gear and a pinion on said lever and meshing with said first spur gear and one of said two spur gears of said gear coupling means coaxial with said pinion, said first spur gear and said pinion constituting said step-up drive; and means connected to said lever for biasing the latter in a direction for holding said two gears of said gear coupling in engagement.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 2 3,907,198

D TE September 23, 1975 INVENTORG) 1 Heinz Kelch and Helmut Mt'iller ltis certified that error appears in the ab0veidentified patent and that said Letters Patent are hereby corrected as shown below:

In the heading [76] the name of the second inventor should read Helmut Miiller In the heading [73] insert Kienzle Apparate GmbH,

Villingen/Schwarzwald, Germany Signed and Scaled this fourth Day of May 1976 [sen] RUTH C. MASON C. MARSHALL DANN Anesring Officer ('mnmissiumr nj'larmrs and Trademarks UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 2 3,907,198

DATED I September 23, 1975 |NV,ENTOR(5) I Heinz Kelch and Helmut Ml'iller It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading [76] the name of the second inventor should read Helmut Mr'iller In the heading [73] insert Kienzle Apparate GmbH,

Villingen/Schwarzwald, Germany Signed and Sealed this fourth Day of May 1976 {SEAL} Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (ommissimu'r oflarmrs and Trademarks

Claims (7)

1. A resettable counter comprising counter wheel means; drive means for driving the counter wheel means; gear coupling means between said drive means and said counter wheel means movable between an engaged position for driving said counter wheel means by said drive means and a disengaged position for allowing resetting said counter wheel means; a step-up drive between said drive means and said gear coupling means; and a step-down drive between said gear coupling means and said counter wheel means to minimize errors caused by reengagement of said gear coupling means after the latter has been disengaged for resetting said counter wheel means.

2. A counter as defined in claim 1 wherein said step-up and step-down drives are gear drives.

3. A counter as defined in claim 2 wherein said drive means comprises a shaft and said gear drive and gear coupling means comprise spur gears in planes normal to said shaft.

4. A counter as defined in claim 1, including means for yieldably holding said gear coupling means in coupled condition.

5. A counter as defined in claim 1, wherein said gear coupling means comprises a pair of spur gears having bevelled extensions on their tooth faces to facilitate said reengagement.

6. A counter as defined in claim 1 wherein said step-down drive has a transmission ratio which is the inverse of the transmission ratio of said step-up drive.

7. A counter as defined in claim 1 wherein said drive means comprises a first spur gear arranged for continuous rotation; said gear coupling means comprising two spur gears in a plane parallel to said first spur gear; and including a lever pivotable about the axis of said first spur gear and a pinion on said lever and meshing with said first spur gear and one of said two spur gears of said gear coupling means coaxial with said pinion, said first spur gear and said pinion constituting said step-up drive; and means connected to said lever for biasing the latter in a direction for holding said two gears of said gear coupling in engagement.

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