Vehicle steering and front-end alignment defect detector

An apparatus for detecting defects in vehicles having a front portion with a right side and left side, a rear portion, at least two front wheels rotatably mounted in said front portion, a rear support means for mobile support of said rear portion of said vehicle, and steering means for steering said front wheels including a steering column, a steering rod rotatable around an axis of rotation, a steering wheel rotatably mounted about said rotational axis and connected to said steering rod, and connecting means for steerably connecting said steering rod to said front wheels, said steering wheel being in a center position when said wheels are aligned for forward motion of said vehicle, each of said front wheels having an inner side wall, an outer side wall, and a road surface contacting portion, said apparatus comprising:

• at least one wheel rotating roller, a vehicle support floor, and roller rotating means, said roller being mounted in said floor along a line substantially perpendicular to the line of forward motion for said vehicle, contacting said surface contacting portions of each of said front wheels, and providing wheel rotating means for rotating each of said front wheels when said steering wheel is turned through a relatively small angle of rotation to urge the front portion of the vehicle to move in the direction of the vehicle's first or second side;
• first retaining means for retaining said vehicle from movement in the direction of the vehicle's first side;
• second retaining means for retaining said vehicle from movement in the direction of the vehicle's second side, each of said retaining means having a base firmly attached to said floor, a block portion rotatably mounted in said base, an arm portion slidably mounted in said block portion, block locking means for locking the position of said block portion with respect to said base, arm locking means for locking the position of said arm portion with respect to said block portion, a force transducer mounted on an end of said arm portion, and a pad adjustably mounted on said force transducer, said pad providing a surface for contacting the respective side of said front portion of said vehicle and transmitting the respective force of said vehicle on said pad to said force transducer, and said force transducer providing signal generating means for generating an electrical signal proportional to said force transmitted by said pad and being electrically connected to a conversion means for converting said electrical signal into a readable measurement of force;
• a torque wrench mounted on said steering rod whereby a first value of rotating torque can be obtained when the steering wheel is rotated about the axis of rotation from said center position through a relatively small angle of rotation to urge the first side of the vehicle against said first retaining means and a second value of rotating torque can be obtained when the steering wheel is rotated about the axis of rotation from said center position through a relatively small second angle of rotation to urge the second side of the vehicle against said second retaining means;
• an indicating plate removably mounted on said steering wheel and having a pointer extending from the periphery of said steering wheel to provide an indication of angular rotation of said steering wheel about the rotational axis of said rod;
• and
• a reading plate removably mounted on said steering column behind said steering wheel and having indicia printed thereon to provide a reading of the angular rotation of said pointer on said steering wheel and whereby said first and second angles of rotation of said steering wheel can be made to be approximately equal in magnitude.

A method of detecting steering defects in vehicles having a front portion with a first side and a second side, a rear portion, at least two front wheels rotatably mounted in said front portion, at least one rear support means for mobile support of said rear portion and steering means for steering said front wheels, said steering means including a steering rod rotatable around an axis of rotation, a steering wheel rotatably mounted about said axis of rotation and connected to said steering rod, and connecting means for steerably connecting said steering rod to said front wheels, said steering wheel being in a center position when said wheels are aligned for forward motion of said vehicle, said method comprising:

• (a) retaining said first side of said vehicle from movement in the direction of said first side;
• (b) retaining said second side of said vehicle from movement in the direction of said second side;
• (c) rotating each of said front wheels of said vehicle;
• (d) rotating said steering wheel in a first direction through a first angle of rotation from the center position so that the vehicle is urged against the first side retaining means with a first force;
• (e) obtaining a first steering force value by measuring the force or torque exerted on said steering means to maintain the position of said steering wheel at said first angle;
• (f) obtaining a first urging force value by determining the force exerted by said first side of said vehicle on said first retaining means while said steering means is maintained at said first angle;
• (g) rotating said steering wheel in a second direction through a second angle from center position so that the vehicle is urged against the second side retaining means with a second force;
• (h) obtaining a second steering force value by measuring the force or torque exerted on said steering means to maintain the position of said steering wheel at said second angle;
• (i) obtaining a second urging force value by determining the force exerted by said second side of said vehicle on said second retaining means while said steering means is maintained at said second angle;
• and
• (j) mathematically comparing said first and second and force values to determine if there is a steering or a front end alignment defect in said vehicle.