Device for measuring the distance travelled and the speed of a rail vehicle

• US 4,922,447 A
• Filed: 10/09/1986
• Issued: 05/01/1990
• Est. Priority Date: 10/09/1985
• Status: Expired due to Fees

• Current Assignee: Alcatel NV (Nokia Corporation)
• Original Assignee: Alcatel NV (Nokia Corporation)
• Inventors: Reichel, Friedbert
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Ramirez, Ellis B.
• Application Number:
  US06/917,345
• Time in Patent Office: 1,300 Days
• Field of Search: 364/561, 364/565, 364/424, 377/24.1, 377/24.2, 377/17, 377/9, 377/19, 33/141.5, 33/142, 33/142 R, 361/239, 361/240, 73/490
• US Class Current: 702/165
• CPC Class Codes: G01C 22/02 by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator G01C22/002, G01C22/004, G01C22/006 take precedence

Abstract

A device for measuring the distance travelled by and the speed of a rail vehicle fitted with wheel-coupled distance-pulse generators is disclosed in which both distance and speed are calculated from the time distance between successive distance pulses, and in which the change in wheel diameter due to wheel wear is already taken into account in the measurement of the time distance between the distance pulses (distance-pulse intervals). To measure the distance-pulse intervals, clock pulses of reduced repetition rate are counted which are obtained by dividing basic clock pulses of high repetition rate in an adjustment divider (T1). The wheel diameter is taken into account by changing the division ratio of the adjustable divider by means of a coding switch (S1).

Claims

1. In a device for measuring distance travelled by and speed of a rail vehicle of the type comprising at least one wheel-coupled distance-pulse generator and one evaluating circuit which calculates the speed of and the distance travelled by the vehicle from elapsed time corresponding to a distance-pulse interval between two or more distance pulses taking account of different wheel diameters, the elapsed time being determined by counting out in a first counter clock pulses of high repetition rate reduced to diameters, the elapsed time being determined by counting out in a first counter clock pulses of high repetition rate reduced to count pulses of reduced repetition rate by means of a first divider having a preset division ratio, the improvement comprising:

a coding switch connected to said first divider which changes the division ratio in accordance with an input identifying the change in a wheel diameter;

a second counter independent of said first counter; and

alternating means coupled between an output of the first divider and respective inputs of the first and second counters for alternately supplying each of said two counters with all the count pulses from said first divider arriving within a particular said distance-pulse interval.

2. A device for measuring the distance travelled by and the speed of a rail vehicle comprising:

a source of clock pulses of high repetition rate;

a first divider coupled to said source of high repetition rate clock pulses and having a preset division ratio to produce clock pulses having a reduced repetition rate;

a coding switch connected to said first divider which changes the preset division ratio in accordance with an input identifying a change in a wheel diameter;

at least one wheel-coupled distance-pulse generator;

a first counter;

a second counter independent of said first counter;

alternating means response to distance pulses from the distance-pulse generator for alternately supplying each of said two counters with all count pulses from said first divider arriving within successive predetermined distance-pulse intervals each corresponding to a predetermined number of distance pulses;

an evaluating circuit which calculates the speed of and the distance travelled by the vehicle during the distance-time interval immediately prior to the current predetermined distance from the number of clock pulses of reduced repetition rate counted by the counter that was supplied by count pulses during such immediately prior distance-time interval;

synchronizing means for synchronizing the clock pulses of reduced repetition rate with said distance pulses; and

selection means responsive to the synchronizing means for coupling the output of the first divider to a particular one of said first counter and said second counter in response to a signal applied to a control input of the selection means.

3. A device as claimed in claim 2, further comprising:

an additional divider coupled between an output of said synchronizing means and the control input of said selection means.

4. A device as claimed in claim 3, wherein said additional divider has an adjustable division ratio.