CAPACITIVE MOVEMENT MEASURING DEVICE

• US 3,723,866 A
• Filed: 04/07/1971
• Issued: 03/27/1973
• Est. Priority Date: 04/10/1970
• Status: Expired due to Term

• Current Assignee: Gilles Delapierre, Jean-Francois Michaud
• Original Assignee: Gilles Delapierre, Jean-Francois Michaud
• Inventors: Michaud, Jean-Francois, Delapierre, Gilles
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US05/131,865
• Time in Patent Office: 720 Days
• Field of Search: 324/61R,61P,61QS 317/246 340/200
• US Class Current: 324/662
• CPC Class Codes: G01B 7/02 for measuring length, width or thickness G01B7/004, G01B7/12 take precedence
• CPC Class Codes: G01D 5/24 by varying capacitance

Abstract

A movement measuring sensor comprises a rule having parallel surfaces and a slider having parallel surfaces opposite the first parallel surfaces and movable relatively to the rule in a direction parallel to the surfaces. Each surface of the slider is provided with a first set of n electrically interconnected conductive strips disposed at a pitch p in such direction and the rule has N electrically interconnected conductive strips disposed at the same pitch p and located opposite each of the first sets. The two capacitances each formed by a set of n strips and a set of N strips are in series relation.

Claims

1. A movement-measuring device comprising a senser, two elements for said sensor, one of said elements being a rule, parallel surfaces for said rule, the other of said elements being a slider, parallel surfaces for said slider opposite said parallel surfaces of said rule, said elements being movable relatively to one another in a predetermined direction parallel to said parallel surfaces, one of said elements having on each of its parallel surfaces a first set of n electrically interconnected conductive strips, n being an integer greater than one disposed at a predetermined pitch in said predetermined direction, the other of said elements having mounted thereon opposite each of said first sets of strips N electrically interconnected conductive strips disposed at the same pitch, N being an integer greater than one;

two capacitances each formed by a set of n interconnecting said capacitances in series; and

means for measuring the total capacitance.

2. A device according to claim 1, wherein said first element having on each of its parallel surfaces a second set of n conductive strips identical to said first set and offset by half of said pitch relatively to said first strips;

and means for measuring the total capacity of the two extra capacitors formed by said second set and by the two sets of N strips, said two capacitors being in series.

3. A device according to claim 2, said rule being a silica rod said parallel comb surfaces of said rod being optically polished.

4. A device according to claim 2, said slider including two plates and means for moving said plates relatively to one another lengthwise to compensate for any offset between said stRips on said two parallel surfaces of said rule.

5. A device according to claim 1, said interconnection between said strips being a metal wire in a groove interconnecting an edge of said strips, the arrangement of said wires reversing at changeover from one of said elements to the other of said element.

6. A device according to claim 1 including means for adjusting the position of said rule in a direction parallel to its surfaces and perpendicular to the movement direction.

7. A device according to claim 1, the rule being guided in the casing by its stripless lateral parts sliding on stripless surfaces of the casing.