BRAKE TESTER WITH TIRE TREAD PROFILE MEASUREMENT ATTACHMENT

TECHNOLOGY FIELD

[0001 ] This disclosure refers generally to apparatus for measuring parameters related to vehicular tires, and, more specifically, to brake testers that measure brake performance and also measure tire treat depth, such as EP1394503, which is incorporated herein in its entirety.

BACKGROUND

[0002] As the automobile industry has matured and automotive use has become an essential mode of transportation, the performance expectations on the automobile buy the owner and driver have risen. These performance

expectations range from the ability of the components to operate in all climates and all weather conditions, to operating efficiently and reliably. A critical part of the automobile is the wheels, which engage that road to translate the driver's expectations into movement.

[0003] Wheels have two wear surfaces: the brake pads of the brakes and the treads of the tires. These wear surfaces need to be checked periodically so that they can be replaced before they wear out and fail to stop the vehicle when necessary.

[0004] Brake testing determines whether the brakes have sufficient stopping power. Tire tread depth measurement determines whether the depth of the tread is sufficient for traction.

[0005] There are devices that test brakes and measure tire tread depth.

However, improvements in the speed and accuracy of doing both, ideally with the same device in a "drive over" testing unit, would be an advantage.

l SUMMARY

[0006] According to its major aspects and briefly recited, the present invention is a device that measures brake performance and tread depth in a single, drive- over device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the figures,

[0008] FIG. 1 is a top perspective view of a brake tester with a tire tread profile measurement attachment, according to an aspect of the disclosure;

[0009] FIG. 2 is a side view of a brake tester with a tire tread profile

measurement attachment, according to an aspect of the disclosure;

[0010] FIG. 3 is a first end view of a brake tester with a tire tread profile

measurement attachment and with the tire tread depth measurement device in its locked position, according to an aspect of the disclosure;

[001 1 ] FIG. 4 is a first end view of a brake tester with a tire tread profile

measurement attachment and with the tire tread depth measurement device in its unlocked position, according to an aspect of the disclosure;

[0012] FIG. 5 is an end view of a brake tester with a tire tread profile

measurement attachment and with a large tire in place on the brake tester, according to an aspect of the disclosure;

[0013] FIG. 6 is an end view of a brake tester with a tire tread profile

measurement attachment and with a smaller tire in place on the brake tester, according to an aspect of the disclosure;

[0014] FIG. 7 is a perspective view of the tire tread profile measurement

attachment, according to an aspect of the disclosure;

[0015] FIG. 8 is a top view of the tire tread profile measurement attachment, according to an aspect of the disclosure;

[0016] FIG. 9 is a side view of the tire tread profile measurement attachment, according to an aspect of the disclosure;

[0017] FIG. 10 is a flow diagram of the process of testing brakes and measuring tire tread depth; and [0018] FIG. 1 1 is a schematic diagraph of the present device.

DETAILED DESCRIPTION

[0019] Disclosed herein is a brake tester with the capability for measuring the profile of a tire to determine tread depth and tire wear. US 6789416, which describes a handheld probe for measuring tire tread depth, is incorporated herein in its entirety by reference.

[0020] FIG. 1 is a top, perspective view of a tire brake tester device 10 that also measures tire tread depth. FIGS. 2, 3 and 4 are a side and two end views of the present device 10, respectively. Device 10 includes a frame 14 made of a material strong enough for a vehicle to drive over it, pausing partway for the tire brake testing and the tread depth scanning. Frame 14 may be duplicated so as to be wide enough for both left and right tires of one axle at a time to be tested, as suggested in FIG. 1 which shows a portion of a second device 10 in parallel with the first one. After testing the front brakes of a vehicle and measuring tire tread depths of the front tires, the vehicle moves forward so that the rear axle is over brake tester device 10 for testing the rear brakes of the vehicle and measuring the tread depths of the rear tires.

[0021 ] Tester device 10 includes two rollers, a driving roller 18 and a driven roller 22, to support and rotate a tire when a tire is position on both driving roller 18 and driven roller 22. Driving roller 18 is driven directly by a motor 26; driven roller 22 is connected to driving roller 18 by means for rotating driven roller 22 such as a belt or a link chain and sprocket 30 driven by motor 26. When motor 26 is rotated, it rotates shaft 54, which in turn rotates driving roller18. Driven roller 22, coupled to driving roller 18 via link chain 30, then rotates in response.

[0022] Tester device 10 may be doubled to test both from brakes or quadrupled to test front and rear brakes. Left and right sides are independent of each other and the rollers and motors are mirror images of each other. Front and back axle testing may be tested at the same time in a coordinated manner so that the testing proceeds quickly and in good order. A second motor 34 is shown in the lower left corner of FIG. 1 to suggest the left side of dual wheel brake tester.

[0023] Driving roller 18 and driven roller 22 are mounted in journal bearings 38, 42, best seen in FIGS 3, 4 and 5, and are spaced apart from each other by a gap. Driving roller 18 and driven roller 22 have surfaces 40, 44, that engage frictionally with a tire 70 (See FIGS 5 and 6) in a manner similar to the surface of a road.

[0024] To test the brakes of the tire, the vehicle with the tire moves so that a tire to be tested is on both driving roller 18 and driven roller 22. See FIGS 5 and 6. As best seen in FIG 10, when the tire is present in position on device 10, motor 26 is activated and its shaft 54 rotates driving roller 18 and driven roller 22.

When the tire is rotating at test speed, the driver of the car receives a signal to apply the brakes to stop driving roller 18. Simultaneously, a timer is started. When driving roller 18 is stopped by the vehicle's brakes, the timer is stopped. The time or effective distance traveled between application of the brakes and the stopping of driving roller 18 is used as a measure of the effectiveness of the brakes in stopping the tire. That time interval or distance traveled to a complete stop is shorter when the vehicle's brake pads are thicker and longer when the pads are worn. The time is greater when the tires are worn than when they are new.

[0025] Tire tread depth is measured by a distance measurement laser scanner 58 positioned between driving roller 18 and driven roller 22. A tire 70 is at rest on both driving roller 18 and driven roller 22 scanning the tread 66. As best seen in FIGS. 7, 8, and 9, laser range finder 58 is mounted to a linear actuator 62 positioned between and below driving roller 18 and driven roller 22. Linear actuator carries a laser rangefinder that scans the tread 66 of tire 70 while being moved laterally across the rolling face of the tire and back again by linear actuator 62, thus making two passes. The rolling face of tire 70 contains tread 66, which is the portion of the tire that engages a roadway when the car is being driven. The measurement of the distance to tread 66 of tire 70 is made transverse to the circumference of tire 70 and forwarded to a controller processor 102 for processing.

[0026] The tired tread depth linear actuator 62 is installed between driving roller 18 and driven roller 22 and is located low enough to be clear of tread 66 of a tire 70 for both larger tires and smaller tires. See FIGS. 5 and 6. A bracket 74 is attached to the top 78 of the linear actuator 62 and travels a rail 82 between the two endpoints 86, 90, on opposing ends of linear actuator 62. Bracket 74 holds laser rangefinder 58 so that the laser light is incident perpendicular to tread 66. Distance data is collected by laser range finder 58 when linear actuator 62 traverses tire tread 66.

[0027] Comparing FIGS. 3 and 4, a pivoting arm 94 is in a locked position in FIG.

3 and an unlocked position in FIG. 4 where it is urged by a spring (not shown) against tread 66 to provide an indication as to the location of the tire surface with respect to the laser range finder 58. Comparing FIG. 5 and FIG. 6, it will be clear that if a smaller tire (FIG. 6) is on driving roller 18 and driven roller 22, tread will be closer than when the tire has a larger radius (FIG. 5). The smaller tire will pivot pivoting arm 94 further. Pivoting arm 94 carries a roller 98 on the end of it. Roller 98 engages tread 66 of tire 70, when pivoting arm 94 is in the unlocked position, and rolls against the surface of tire 70. As pivoting arm 94 is pivoted downward further by the surface of a smaller diameter tire than it would be by a larger diameter tire, the angle of pivoting arm 94 may thus indicate the nominal distance to tread from laser range finder 58.

[0028] As shown in FIG. 1 1 , a controller processor 102 controls the sequence of steps for both brake testing and tire tread depth measurement, including a tire present sensor 104 that senses when a tire 90 is present and in position on driving roller 18 and driven roller 22. Controller processor 102 activates motor 26 to begin rotating driving roller 18 and driven roller 22. When motor 26 is at an speed appropriate for testing, a signal such as a light or buzzer or both, may be given to the driver to apply the brake. That signal activates a timer for recording the time from application of brakes to full stop of the tire 90. Tire speed is determined by the speed of motor 26. [0029] Controller processor 102 also actives linear actuator 62 and laser range finder 58 and records the data received from range finder 58 and the position of pivoting arm 94. Controller processor 102 forwards the measurements and tire profile data to a processor 98 for calculation and forwarding the results to a display 120.

[0030] Scanner is oriented to direct a laser perpendicular to the rolling face

measuring the depth of the tread, which is related to the tread depth of a new tire and the difference is the tire wear. The tread depth might not be uniformly thinner after a period of time during which the tire has been in use but rather the tire tread may have become uneven. Unevenness can be related to the misalignment of the tires, which can be brought to the attention of the vehicle owner who may have the alignment corrected as part of an effort to make the tires wear out more uniformly. When tires wear out uniformly, they can be replaced all at one time. When tire wear is significantly different from one tire to another on the same vehicle, that difference may affect the way the vehicle stops in an emergency, and potentially cause the vehicle to become out of control of the driver.

[0031 ] Brake testing and tire tread depth measurement are important to do often and to do at the same time. Tire wear and brake wear both affect stopping power. If brakes are worn but tires are new, the results of brake testing may suggest the brakes are fine. If the brakes are new but the tires are worn, the results of brake testing may show that the brakes need to be replaced when, in fact, they do not need to be. Accordingly, the combination of a brake tester and a tread depth measurement being done at the same time is not a solely for the convenience of the driver but also provides better quality information than when these measurements are done at different times or using different pieces of equipment.

[0032] Moreover, the use of a brake tester in connection with a tire tread depth measurement device enables a second tire tread depth measurement across a different section of the tire tread. By rotating the tire less than 360 degrees using the motors that rotate the tires for brake testing, the tire tread scanner can then traverse the tread at a second location of the tire circumference and the results correlated with the first traversal. Several traversals of laser rangefinder can be used to obtain a more complete set of data of tire wear.

3] Those skilled in the art of vehicular maintenance, testing and tire parameter measurement will appreciate that many modifications and

substitutions may be made to the foregoing description of aspects of the disclosure without departing from the spirit and scope of the disclosure.