Registers – Transfer mechanism – Differential gears
Patent
1989-07-18
1991-06-25
Heyman, John S.
Registers
Transfer mechanism
Differential gears
235119, 235134, 377 82, G06M 108
Patent
active
050269739
DESCRIPTION:
BRIEF SUMMARY
This invention relates to number wheel counters and in a particular example to counters adapted to provide an electrical output.
It is known that the number wheels of generally conventional number wheelcounters can be adapted--for example by providing them with wipers engaging fixed contact arrays--to produce an encoded electrical output signal which is indicative of the counter reading. It is then possible to read such a counter by interrogation over a suitable communication line or through the use of a portable reading unit which is periodically connected to the counter via a suitable interface. Such counters have been proposed for use with meters which measure domestic or industrial water consumption or indeed other public utilities.
It has been recognised as a problem with such counters that the wipers which are connected to the number wheels may actually be between contacts at the instant at which the counter reading is read. This problem arises most frequently with the least significant number wheel although the remaining number wheels will be affected at decade intervals and an error in reading one of the more significant number wheels is of course more serious. One solution that has been proposed to deal with this difficulty is to take counter readings in pairs, and to accept the readings only if they are the same, so confirming that there has been no movement of the number wheels.
In an alternative proposal, a number wheel counter has been Provided in which the number wheels are driven in a stepwise manner rather than continuously, as is the conventional case. In this way the risk of the number wheel wiper being positioned between fixed contacts at the instant of meter reading, is very much reduced. The known mechanisms for achieving this purpose are however bulky and add significantly to manufacturing costs. In addition they frequently impose high torque requirements.
It is an object of this invention to provide an improved number wheel counter which is mechanically simple and compact yet which provides for the number wheels to be moved rapidly from one number position to the next.
Accordingly, the present invention consists in a number wheel counter comprising a plurality of interconnected number wheels; a worm wheel connected with a first one of the number wheels; a worm gear positioned in driving engagement with the worm wheel; and means for rotating the worm gear about its longitudinal axis to effect rotation of the worm wheel and thereby rotation of the first number wheel; wherein there is further provided cam means for displacing the worm longitudinally away from a rest position in synchronism with rotation thereof, such that the worm wheel remains stationary over a worm gear rotation corresponding with a number interval of the first number wheel, and biassing means for restoring the worm gear rapidly to its rest position to drive the first number wheel through a number interval.
Advantageously, the means for rotating the worm gear comprises a gear mounted coaxially and fixed for rotation with the worm gear, said cam means comprising complementary cam surfaces on said gear and on a fixed cam.
The invention will now be described by way of example with reference to the accompanying drawings in which:
FIG. 1 is a front view, partly in section, of the operative portion of a number wheel counter according to this invention;
FIG. 2 is a plan view of the part shown in FIG. 1.
FIG. 3a is an enlarged sectional front view of the driven gear shown in FIG. 1.
FIG. 3b is an enlarged front view of the fixed cam shown in FIG. 1.
FIG. 4 is a part view similar to FIG. 1, illustrating a modification.
The number wheel counter illustrated in the drawings comprises a bank of coaxial number wheel counters only the least significant of which is shown in the drawings at 10. The remaining number wheels are of conventional form and are driven from the first number wheel 10 through transfer pinions or in any other suitable manner such that a complete revolution of one number wheel drives the next succeeding number wh
REFERENCES:
patent: 3019974 (1962-02-01), Bliss et al.
patent: 3780524 (1973-12-01), Boyles
patent: 3875376 (1976-04-01), Kakeno
patent: 3931705 (1976-01-01), Iwaki et al.
patent: 4257324 (1981-03-01), Stefansson et al.
ABB Kent PLC
Heyman John S.
LandOfFree
Number wheel counters does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Number wheel counters, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Number wheel counters will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1042025