US3448624A

US3448624A - Exponential multiturn lost-motion device

Info

Publication number: US3448624A
Application number: US505071A
Authority: US
Inventors: Robert A Brown
Original assignee: Duncan Electric Co Inc
Current assignee: Landis and Gyr Metering Inc
Priority date: 1965-10-24
Filing date: 1965-10-24
Publication date: 1969-06-10
Anticipated expiration: 1986-06-10

Description

June' 10, 1969 A WN EXPONENTIAL MULTITURN LOST-MOTION DEVICE Filed Oct. 24, 1965 INVENTOR.

Wfm J 7W United States Patent 3,448,624 EXPONENTIAL MULTITURN LOST-MOTION DEVICE Robert A. Brown, Lafayette, Ind., assignor to Duncan Electric Company, Inc., a corporation of Indiana Filed Oct. 24, 1965, Ser. No. 505,071 Int. Cl. F16h 35/18 US. Cl. 74-10.2 Claims ABSTRACT OF THE DISCLOSURE A lost-motion device which will permit a multiple of turns within the limits of lost motion, and can be designed to permit many turns, is provided by a plural stage Geneva mechanism in which the last stage is provided with a stop device. Stop accuracy is obtained by a stop member carried by one element of the last stage which moves into position for being struck by a Geneva transfer unit having relative high speed movement at the time of striking. With unequal rotation between these elements, the transfer element may be notched so as not to strike the stop member until the second or third time it comes into the stop position. The device may be used as a lost-motion stop or as a lost-motion drive.

The invention of which this disclosure is offered for public dissemination in the event that adequate patent protection can be given relates to devices which are capable of many, :many turns of lost motion. Lost-motion devices are useful in a wide range of applications. Sometimes they are used merely as stops. Other times they are used for measuring the amount of movement from a stop or back to a stop.

The present owner is especially interested in the use of multiturn lost-motion devices in connection with meters, and especially electricity (watt-hour) meters. Multiturn lost-motion devices have been used in this connection before, especially in maximum demand registers which must be reset periodically to zero. Before they have served as a zero stop, while permitting more than one turn in the advancing direction. However, the known multiturn stops have been quite limited. They required a separate disc for each turn, or even a little less than each turn. Hence, even a moderate number of turns required a device which was quite bulky, and a large number of turns became prohibitive. Furthermore, there appeared to be same danger of growing inaccuracy due to possible wear or deformation at the multitude of contact points by which a stop position had to be determined.

According to the present invention, a Geneva type lostrnotion device is provided which is exponential in nature. Thus, if the common decimal relationship is used, each added Geneva stage multiplies by ten the number of turns which would be accommodated without. Thus, a single Geneva stage driving a final stage can accommodate approximately ten turns, but two Geneva stages driving a final stage can accommodate approximately a hundred turns. And with a third Geneva stage, approximately a thousand turns could be accommodated. It is apparent that there would very rarely be need for more than a thousand turns, but the three Geneva stages and the final stage of such a device can be quite compact. Furthermore, since only a few different parts are required and the total number of parts is not great, the cost is quite low. Because of the manner in Which the entire lost motion device locks up at the stop position, and because of the exponential factor which reduces the number of contact points, as compared to a multiple disc device, the danger of increasing error due to wear is negligible.

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Two or more other patent applications have been filed on specific uses of the device of this invention.

Additional objects and advantages of the invention will be apparent from the following description and from the drawings.

Designation of the drawing figure The single figure of the drawings is a perspecive view of one form of the invention chosen for illustration, parts being elongated for clarity of illustration.

Although the following disclosure offered for public dissemination is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose, as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

General description In the illustrated form of the invention, the lost motion occurs between the gear 51 and the shaft 58. If they are turned in either direction they will come to a relative stop. Then, in the opposite direction they can be turned many, many turns. Ordinarily, it will not be desired to reach the limit in the opposite direction, but in the form illustrated it would be approximately a hundred turns.

The two

external connecting elements

51 and 58 may be variably connected. The gear 51 obviously would normally be driven by a pinion engaging it. The shaft 58 could be driven if desired, it could be locked entirely against motion, or it could be permitted limited motion when the gear 51 has closed up the lost motion. This could be a small limited motion such as might be used to actuate a switch or otherwise produce some eifect which is desired when the stop position is reached. It could be a greater motion, as to indicate maximum demand, the gear 51 serving as the transient demand indicator or pusher. If the shaft 58 is driven, it would be possible that either the gear 51 or the shaft 58 be driven away from the stop or closed up position.

The zero, stop, closed-up, locked position The drawing shows the lost motion device very close to its stop position. This is best explained by assuming that the gear 51 is held stationary and the shaft 58 is turned clockwise.

The first stage rotor 32 is fast on shaft 58. With only a slight turn of shaft 58 actuating dog 57 will strike one of the teeth of pinion 73, turning this pinion which turns gear 77. Gear 77 is part of the intermediate stage rotor 78 and therefore it turns dog 81, this entire rotor being turned clockwise. Dog 81 strikes one of the teeth of pinion 84 and turns this pinion in a counterclockwise direction. However, this pinion barely begins to move before stop 89 on gear 88 strikes tooth 86 of pinion 84 which is seeking to mesh with gear 88. This blocks rotation of gear 88 and pinion 84 which in turn blocks movement of dog 81 and the remainder of rotator 78. Its gear 77 blocks rotation of pinion 73 which in turn blocks further movement of dog 57. Since that is fast on shaft 58, the lost motion is locked-up as to relative motion in the direction indicated.

If we assume that gear 51 is not held firmly, shaft 58 will turn the entire lock-up assembly, driving gear 51 and anything meshing with it.

The same locked-up condition would have been reached from the illustrated position if we assume that the shaft 58 were held stationary and gear 51 were turned counter clockwise for that would be turning the

entire cage

51, 52, 53, 74, and would cause tooth pinion 73 to strike stationary dog 57, which in turn would set up the Geneva locking action described. In other words it makes no diiference as to the locking action whether it is brought about by moving dog 57 clockwise or revolving the pinion 73, with the cage, counter clockwise.

Accumulation of lost motion From the locked-up position, either shaft 58 or gear 51 may be turned many many turns in the opposite direction from that which produced the locked-up condition. Specifically if shaft 58 remains stationary gear 51 can turn approximately a hundred turns in the clockwise direction. The action is easier to explain, however, if we assume that gear 51 is held stationary and shaft 58 is turned in the counterclockwise direction, and we will see that it can be turned approximately one hundred revolutions.

The first stage couple or rotor 32 of course rotates with shaft 58. Initially, rotation of

pinions

72 and 73 is prevented by virtue of the fact that two of the teeth 71 ride on, or approximately on the periphery of notched disc 56. The pinion 72 may thus be called a Geneva rider. However, as rotator 32 is completing its first counterclockwise turn from the position shown, dog 57 engages one of the teeth of pinion 73 at the same time that notch 76 reaches a position to receive one of teeth 71. Accordingly, the forked or two-toothed dog 57 can pass through the bite between rotor 32 and

pinions

72 and 73, turning the pinions which are locked together. Pinion 73 is turned through the angularity of two teeth and it in turn turns gear 77 through the angularity of two teeth. This is one tenth of the revolution for gear 77 since gear 77 has twenty teeth. It follows that on the tenth pass of dog 57 through the bite, dog 81 of intermediate stage rotor 78 in its two tooth move, will also pass through the bite. Thus it will rotate six-tooth pinion 84 and with it threetooth pinion 83, with notch 87 of disc 79 receiving one of the teeth 82. Pinion 84 will turn gear 88 one tenth of a revolution. As this is about to be repeated the tenth time, the one-hundreth revolution of shaft 58 and actuating dog 57, stop 89 will be struck by one of the teeth of pinion 84. This will be the limit of the lost motion from the previous stop position. It is, of course, another lockedup or stop position. Either one can serve as the starting position for lost motion. Although there may be some use in which both stop positions would be used, ordinarily the device will move for lost motion with respect to only one of its stop or locked-up positions.

Although the pinions on shaft 74 have been described as three and six-toothed pinions, they could be four and eight-tooth pinions, and in fact have been so illustrated. The action is the same either way.

If the tooth 86 or another tooth which the stop 89 would strike should be notched to receive the stop 89, and allow it to pass, stop 89 will make a second revolution before striking another tooth of pinion 84. Thus twice as much lost motion would be provided between the opposite limits. With a six-tooth pinion, two teeth could be thus notched to receive stop 89 and allow it to pass, these two teeth being spaced by one tooth to provide a third revolution of stop 89 and at the end of which it would strike a third tooth of pinion 84, and three times the amount of lost motion would be provided. Of course, ten times as much lost motion can be provided by adding a second intermediate stage 78 with its associated set of

pinions

82 and 84, and any number of turns could be accommodated by successive such additions.

Achievement The compactness of the device which permits such large numbers of turns is hardly apparent from the drawing which is greatly stretched out for the purpose of clarity. It is apparent however, that there are relatively few 4 different parts in the unit, and even the total number of parts is not great for such versatility. It is also apparent that this entire unit can be pre-assembled and is complete within itself so that it does not greatly increase the difficulty of assembling any device with which it is used. In uses where accuracy of the stop (closed-up) condition is important, this is achieved. In spite of the large number of turns available, the locking-up condition is achieved on a basis of large scale motion, rather than a geared down motion which would be necessary to permit such large number of turns with any ordinary lost-motion device. The same exponential characteristic which permits such few stages to yield so many turns of lost motion, also reduces the number of points of contact involved in the locked up condition, and they are of such nature that wear or deformation which could cause an increasing inaccuracy is unlikely.

I claim:

1. A multiturn exponential lost-motion device includa first stage Geneva couple comprising a notched disc and a two tooth dog beside the notch; a Geneva rider engaging the rim of the disc and restrained thereby from turning on the rider axis except as the notch passes through the bite between them, a pinion coupled to the rider and turned with it by the dog as the notch and dog pass through the bite;

a second stage Geneva unit including a gear driven in response to rotation of the prior stage pinion, a notched disc, a two toothed dog beside the notch, a Geneva rider engaging this disc and restrained thereby from turning on the rider axis except as the notch passes through the bite, a pinion coupled to the rider and turned with it as the notch and dog pass through the bite;

at final stage including a gear driven in response to the rotation of the prior stage pinion and means for limiting the rotation of this gear, and

external relatively rotatable connections for causing relative rotation between the first and final stages;

the means for limiting the rotation of the final stage gear being eifective at a point in its rotation such that there is dog and pinion engagement preventing uninterrupted rotation of the first stage couple relative to the device as a whole.

2. A multi-turn exponential lost-motion device includa first stage Geneva couple comprising a notched disc and a two tooth dog beside the notch; a Geneva rider engaging the rim of the disc and restrained thereby from turning on the rider axis except as the notch passes through the bite between them, a pinion coupled to the rider and turned with it by the dog as the notch and dog pass through the bite;

a final stage including a gear driven in response to the rotation of the prior stage pinion .and means for limiting the rotation of this gear, and

the means for limiting the rotation of the final stage gear being effective at a point in its rotation such that there is dog and pinion engagement preventing uninterrupted rotation of the first stage couple relative to the device as a whole. i

3. A multi-turn exponential lost-motion device including:

a first stage Geneva rotor,

a second stage Geneva rotor,

a final stage rotor including means for rotation of this rotor, and

Geneva linkage means between the stages for turning each stage a part revolution for each full revolution of the prior stage, and

limiting the the means for limiting the rotation of the final stage rotor being efiective at a point in its rotation such that there is linkage means engagement preventing uninterrupted rotation of the first stage rotor rela tive to the device as a whole.

4. A multi-turn exponential lost-motion device includa first stage Geneva rotor,

a second stage Geneva rotor,

a final stage rotor including means for limiting the rotation of this rotor, and

Geneva linkage means between the stages for turning each stage a part revolution for each full revolution of the prior stage;

the means for limiting the rotation of the final stage rotor being effective at a point in its rotation such that there is linkage means engagement preventing uninterrupted rotation of the first stage rotor relative to the device as a whole.

5. A multi-turn exponential lost-motion device includa first stage Geneva rotor,

the means for limiting the rotation of the final stage rotor being effective at a point in its rotation such that there is linkage means engagement preventing uninterrupted rotation of the first stage rotor rela tive to the device as a whole.

References Cited UNITED STATES PATENTS 3,333,477 '8/1967 Denkowski 7410.2

1,339,052 5/1920 Bauer 74-102 489,703 1/ 1893 Balzer 74--436 X 3,015,793 1/1962 Fraser et a1. 74'10.2 X

MILTON KAUFMAN, Primary Examiner.

US. Cl. X.R. 74-436, 526