System for measuring irregularities of road surface

• US 4,896,964 A
• Filed: 10/01/1987
• Issued: 01/30/1990
• Est. Priority Date: 10/10/1986
• Status: Expired due to Fees

• Current Assignee: Dan T. Moore Company, Tokyo Keiso Company
• Original Assignee: Tokyo Keiso Company
• Inventors: Kitazume, Masahiro
• Primary Examiner(s): Rosenberger, Richard A.
• Application Number:
  US07/103,286
• Time in Patent Office: 852 Days
• Field of Search: 356/1, 356/5, 356/376, 73/146
• US Class Current: 356/602
• CPC Class Codes: G01B 11/306 for measuring evenness

Abstract

A system for measuring irregularities of a road surface, wherein laser rays irradiated on the road surface are received and processed in a predetermined manner. This system includes a body frame mounted on the road surface, a movable frame movably supported by this body frame, and a laser ray transmitting-receiving section connected to this movable frame. The laser ray transmitting-receiving section is additionally provided thereon with a signal process circuit, by which received signals are processed in a predetermined manner, whereby the irregularities of the road surface are measured. Processing performed in the signal process circuit is controlled in timing in accordance with a moving speed of the laser ray transmitting-receiving section.

Claims

1. A system for measuring irregularities of a road surface by the use of laser rays, comprising:

(a) a laser ray transmitting and receiving section positioned above said road surface;

(b) a body frame for holding said laser ray transmitting and receiving section at a predetermined height; and

(c) carrier means mounted on said body frame for moving said laser ray transmitting and receiving section along said body frame from one end to the other, said laser ray transmitting and receiving section being operatively connected to an exciting circuit section for energizing the continuous operation of said laser ray transmitting section, said laser ray transmitting and receiving section being operatively connected to a signal process circuit section for receiving reflected and diffused rays from said road surface, and detecting irregularities information, said signal process circuit section comprising;

(i) means for producing pulse signals at a predetermined timing;

(ii) a plurality of frequency dividers for receiving said pulse signals;

(iii) means for selecting one of said frequency dividers to obtain a desired output signal;

(iv) means for receiving a signal from said laser ray receiving section; and

(v) a signal process circuit for receiving a signal from said receiving means to determine distance information and irregularities information, said signal process circuit being actuated in synchronism with said output signals from said selected frequency divider;

whereby the number of times of signal processing per unit time to received signals in said signal process circuit is changed in synchronism with a moving speed of said laser ray transmitting and receiving section on said body frame.

2. The system for measuring irregularities of a road surface as recited in claim 1, wherein said frequency dividers perform timing regulation of said signal process circuit through an encoder and said encoder is connected to a driving source of said carrier means to be rotatably driven.

3. The system for measuring irregularities of a road surface as recited in claim 1, wherein said carrier means comprises;

a frame that is movable on said body frame in a direction that is parallel to the road surface;

a chain mechanism for moving said movable frame; and

means for driving said chain mechanism.

4. The system for measuring irregularities of a road surface as recited in claim 3, wherein said laser ray transmitting and receiving section is relatively movably connected to said movable frame.

5. The system for measuring irregularities of a road surface as recited in claim 3, wherein said laser ray transmitting and receiving section is relatively movably connected to said movable frame, and said movable frame is provided thereon with means for regulating a range of movement of said laser ray transmitting and receiving section relative to said movable frame.

6. The system for measuring irregularities of a road surface as recited in claim 5, wherein said laser ray transmitting and receiving section is movable a predetermined distance together with said movable frame in a state of being engaged with said movable range regulating means.

7. The system for measuring irregularities of a road surface as recited in claim 3, wherein said chain mechanism includes a pair of gears rotatably supported by said movable frame and a chain endlessly guided around said gears and wherein said laser ray transmitting and receiving section is connected to a portion of said chain.

8. A system for measuring irregularities of a road surface comprising:

(a) a laser ray transmitting-receiving section including a laser receiving portion which provides an output indicative of a point of impingement of said laser ray;

(b) means for moving said laser ray transmitting-receiving section at a predetermined height over said road surface at a measurable speed; and

(c) means for processing at variable intervals signals from said laser ray receiving portion to obtain at least one value from which changes in the height of said road surface may be calculated, said processing means comprising;

(i) means for producing pulse signals at a predetermined timing;

(ii) a plurality of frequency dividers for receiving said pulse signals;

(iii) means for selecting one of said frequency dividers to obtain a desired output signal;

(iv) means for receiving a signal from said laser ray receiving portion; and

(v) a signal process circuit for receiving a signal from said receiving means and said signal from said selected frequency divider to determine distance information and irregularities information.

9. The system as recited in claim 8, wherein said signal process circuit alters said variable interval based on the speed of movement of said laser ray transmitting-receiving section on said moving means.

10. The system as recited in claim 8, wherein said the number of times of signal processing per unit time to received signals in said signal processing circuit is changed in synchronism with said moving speed of said laser ray transmitting-receiving section.

11. The system as recited in claim 10, wherein said moving means comprises:

a body frame;

a movable frame movably mounted on said body frame, said movable frame having said laser ray transmitting-receiving section movably mounted thereon so that movement of said movable frame causes movement of said laser ray transmitting-receiving section in a direction parallel to said road surface; and

controllable means for moving said movable frame.

12. The system as recited in claim 11, wherein said laser ray transmitting-receiving section is movably mounted on said movable frame and, further, wherein said system further comprises

means for imposing limits on the amount of travel of said integral laser ray transmitting-receiving section with respect to said movable frame.

13. The system as recited in claim 12, wherein said laser ray transmitting-receiving section may engage said means for imposing so that said laser ray transmitting-receiving section and said movable frame may move together.

14. The system as recited in claim 13 further comprising means for detecting a time difference between the inputting of a laser ray output signal and the receiving of said laser ray receiving signal.