TIRE TREAD DEPTH MEASUREMENT SYSTEM

• US 3,740,710 A
• Filed: 06/01/1971
• Issued: 06/19/1973
• Est. Priority Date: 06/01/1971
• Status: Expired due to Term

• Current Assignee: Arthur Weintraub, Henry A. Kalina, Robert F. Cahill
• Original Assignee: Arthur Weintraub, Henry A. Kalina, Robert F. Cahill
• Inventors: Weintraub, Arthur, Kalina, Henry A., Cahill, Robert F.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Mooney, Robert J.
• Application Number:
  US05/148,565
• Time in Patent Office: 749 Days
• Field of Search: 340/52R,52,213R,421 73/146,8 209/80,82
• US Class Current: 73/146
• CPC Class Codes: B60S 5/00 Servicing, maintaining, repairing, or refitting of vehicles vehicles adapted to carry a workshop for servicing or maintenance B60P3/14; servicing rail locomotives B61K
• CPC Class Codes: G01B 7/06 for measuring thickness measuring during the manufacture of coatings C23C14/54

Abstract

An automatic tire tread depth measurement system for automobiles wherein two support units are located to receive two tires mounted on an axle. Three probe plates, each probe plate containing 20 spring-loaded probe pins in a staggered configuration, are mounted in each of the support plates. The two outer probe plates of each set of three are located so as to respond to the two peripheral tread grooves of each tire if they are of sufficient depth. The center probe plate of each set is positioned to respond to one of the center grooves of each tire if it is of sufficient depth. A two-position switch is connected to each of the probe pins, each switch having one output if the probe with which it is associated is depressed and another output if the probe with which it is associated is not depressed. The simultaneous signal outputs from the switches are multiplexed to provide switching signals in serial form and are provided to a logic network for processing. The logic network provides a '"'"''"'"''"'"''"'"'pass'"'"''"'"''"'"''"'"' signal if all six tested grooves of the two tires on an axle are satisfactory and a '"'"''"'"''"'"''"'"'fail'"'"''"'"''"'"''"'"' signal if any one of the grooves is worn more than a predetermined amount.

Claims

1. An automatic tire tread depth measurement system comprising:

support means for positioning and supporting a tire having a tread to be tested;

a plurality of vertically movable probes extending from said support means for sensing the tread condition of said tire, a plurality of switches each coupled to a respective probe and providing a plurality of condition signals corresponding to the presence and absence of grooves exceeding a selected depth in said tire treads, each of said probes adapted to be depressed less than a first distance upon alignment with a tread groove exceeding said selected depth and depressed a second distance equal to or greater than said first distance upon alignment with a portion of said tread other than a groove exceeding said selected depth, each switch providing a first probe signal when the probe to which it is coupled is depressed less than said first distance and a second probe signal when the probe to which is it coupled is depressed said second distance; and

logic means coupled to said switches responsive to said plurality of condition signals for providing a first decision signal when said tire tread is satisfactory and a second decision signal when said tire tread is unsatisfactory.

2. The automatic tire tread depth measurement system, according to claim 1, wherein said plurality of probes comprises:

a first group of probes positioned to contact a first outer tread portion of said tire, said first outer tread portion including a first outer groove;

a second group of probes positioned to contact a second outer tread portion of said tire, said second outer tread portion being opposite said first outer portion and including a second outer groove; and

a third group of probes positioned to contact a center tread portion of said tire, said center tread portion including a center groove.

3. The automatic tire tread depth measurement system, according to claim 3, wherein said probe signals provided by said plurality of switches coupled to said first and second groups of probes occur simultaneously, and including a parallel-to-serial converter coupled to receive said probe signals from said switches coupled to said first and second groups of probes and provide first and second serial groups of pulse signals corresponding to the positions of the probes of said first and second probe groups, respectively;

said logic means being coupled to receive the probe signals from said switches coupled to said third group of probes for providing a compound signal in response to the presence of at least one first probe signal among said last mentioned probe signals, said first and second serial groups of pulse signals and said compound signal together comprising said plurality of condition signals for said logic means.

4. The automatic tire tread depth measurement system, according to claim 3, wherein said logic means includes means responsive to said first and second serial groups for providing an affirmative signal when a first probe signal occurs within a selected number of pulses after the initial second probe signal in each of said serial groups.

5. The automatic tire tread depth measurement system, according to claim 4, wherein said responsive means includes:

a pulse counter; and

means for resetting said counter after the reception of said first serial group and prior to the reception of said second serial group.

6. The automatic tire tread depth measurement system, according to claim 5, further comprising:

combining means coupled to receive said affirmative signal and said compound signal to provide a combination signal in response thereto; and

processing means responsive to the presence of said combination signal for providing said first decision signal and to the absence of said combination signal for providing said second decision signal.

7. An automatic tread depth measurement system for automobile tires comprising:

first and second support means each adapted to receive one of a pair of tires mounted on a first axle, said first and second support means being laterally displaced one from the other; and

sensing means coupled to said first and second support means, said sensing means responsive to the depth of the two outer tread portions and the center tread portion of each of said pair of tires for providing a first decision signal if all said tread portions exceed a preselected depth, and a second decision signal if any one of said tread portions does not exceed said preselected depth, first, second and third groups of vertically movable probes mounted in said first support means;

fourth, fifth and sixth groups of vertically movable probes mounted in said second support means, each of the probes of said first and second probe groups and said fourth and fifth probe groups positioned to be moved a distance related to the depth of the two outer tread portions of each of said pair of tires respectively, and each of the probes of said third and sixth probe groups positioned to be moved a distance related to the depth of the center tread portion of each of said pair of tires, respectively;

a plurality of switches, each switch coupled to a respective one probe of said probe groups for providing a position signal dependent upon the vertical position of the associated probe for providing a plurality of position signals; and

logic means coupled to receive said plurality of position signals and providing said first and second decision signals in response thereto.

8. The automatic tread depth measurement system for automobile tires, according to claim 7, further comprising:

first contact means mounted on said first support means responsive to the presence of a tire thereon and providing a first contact signal;

second contact means mounted on said second support means responsive to the presence of a tire thereon for providing a second contact signal; and

control means responsive to said first and second contact signals for preparing said system to respond to said pair of tires and to subsequent contact signals for preparing said system to respond to subsequent pairs of tires.