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Browse Prior Art Database

Linear Motion Clock and Distance Detector

IP.com Disclosure Number: IPCOM000083431D
Original Publication Date: 1975-May-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 3 page(s) / 55K

Publishing Venue

IBM

Related People

Goodrich, RA: AUTHOR [+3]

Abstract

This linear motion detector includes a nonmagnetic rod 5 that moves in unison with the device which is to be monitored for position or velocity. The rod 5 has mounted at the end thereof, a pair of permanent magnets 6 enclosed within a nonmagnetic end cap 7 and a shock absorber bushing 8. Mounted between end enclosure 9 and the support member 10, through which the rod 5 is guided, is a cylindrical housing 12 which confines a non-magnetic coil spool 13 about which is wound a series of stationary coils 14.

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Linear Motion Clock and Distance Detector

This linear motion detector includes a nonmagnetic rod 5 that moves in unison with the device which is to be monitored for position or velocity. The rod 5 has mounted at the end thereof, a pair of permanent magnets 6 enclosed within a nonmagnetic end cap 7 and a shock absorber bushing 8. Mounted between end enclosure 9 and the support member 10, through which the rod 5 is guided, is a cylindrical housing 12 which confines a non-magnetic coil spool 13 about which is wound a series of stationary coils 14.

As illustrated in Fig. 2, each of the coils 14 is connected to a zero-crossing detector 16 (of which only four are shown). When the rod 5 is reciprocated, as indicated by the arrow B, the permanent magnets 6 progress sequentially through the coils 14 inducing in each, an initial positive going signal and thereafter a negative going signal. Using a zero-crossing detector 16, the passage of the permanent magnet assembly 6 past each individual coil 14 is sensed, permitting the determination of both position and in conjunction with the pitch between coils, velocity of the associated rod 5.

The zero-crossing detector (ZCD) lf of Fig. 3 is representative of logic that can be used to generate a signal, as the permanent magnets 6 induce a voltage in a coil 14. The ZCD output at point A goes from a 0 state to a 1 state and returns to a 0 state, based upon the clipping level established by resistor 18.

The negative going edge of the output pulse from ZCD 16 at point A is transmitted to negative edge flip-flop 17, causing an output to single-shot 19. The single-shot output provides the signal indicative of the presence of the permanent magnet assembly 6 at the particular coil location, while the negative condition at the termination of the single-shot resets the associated flip-flop 17.

As seen in Fig. 2. as the permanent magnet assembly 6 moves from a home position to a full extended position with the enable line 21 active, the passage of each coil 14 causes...