US5244226A — Trailer and steerable wheels therefor

Claim 1

Independent Claim 188 words

A method of steering the wheels of a two wheel trailer, and comprising the steps of: monitoring an angle of articulation in magnitude and sense between said trailer and a towing vehicle and generating articulation angle signals in response thereto; monitoring an angle of wheel steering in magnitude and sense relative to an axle of said trailer and generating wheel steering angle signals in response thereto; computing values of said articulation angle as a percentage of a range of articulation to either side of 0°, in response to said articulation angle signals; computing values of said wheel steering angle as a percentage of a range of steering to either side of 0° in response to said wheel steering angle signals; comparing said articulation percentage values with said wheel steering percentage values and generating a correction signal whenever said articulation and steering percentage values are not of equal magnitude; and turning said wheels in response to said correction signal to adjust said wheel steering angle, whenever said articulation percentage value and said wheel steering percentage value are not equal in magnitude, in order to make said percentage values equal.

Claim 2

Independent Claim 188 words

A method of steering the wheels of a two wheel trailer, and comprising the steps of: monitoring an angle of articulation in magnitude and sense between said trailer and a towing vehicle and generating articulation angle signals in response thereto; monitoring an angle of wheel steering in magnitude and sense relative to an axle of said trailer and generating wheel steering angle signals in response thereto; computing values of said articulation angle as a percentage of a range of articulation to either side of 0°, in response to said articulation angle signals; computing values of said wheel steering angle as a percentage of a range of steering to either side of 0° in response to said wheel steering angle signals; comparing said articulation percentage values with said wheel steering percentage values and generating a correction signal whenever said articulation and steering percentage values are not of equal magnitude; and turning said wheels in response to said correction signal to adjust said wheel steering angle, whenever said articulation percentage value and said wheel steering percentage value are not equal in magnitude, in order to make said percentage values equal.

Claim 3

Dependent Claim 76 words

The method as in claim 1, and further comprising the steps of: sensing transitions between forward and reverse modes of travel of said trailer and generating transition signals in response thereto; and for each of said transitions, changing said wheel steering angle, in response to said transition signals, from a pretransition angle other than 0° to a post-transition angle which is equal to said pretransition angle in magnitude and opposite to said pretransition angle in sense.

Claim 4

Independent Claim 139 words

A method of steering the wheels of a two wheel trailer, and comprising the steps of: detecting an articulation angle between said trailer and a towing vehicle; steering said wheels by changing a wheel steering angle automatically according to changes in said articulation angle; identifying forward and rearward directions of travel of said trailer; providing a fluid circuit having a motive fluid for effecting said steering in response to said detecting and for interconnecting said angle detecting and said steering via said circuit; providing a valve for controlling a direction of flow of said motive fluid; and controlling routing of said motive fluid through said circuit via said directional control valve and automatically according to each of said directions of travel so as to provide a particular sense of said wheel steering angle according to said direction of travel.

Claim 5

Independent Claim 139 words

A method of steering the wheels of a two wheel trailer, and comprising the steps of: detecting an articulation angle between said trailer and a towing vehicle; steering said wheels by changing a wheel steering angle automatically according to changes in said articulation angle; identifying forward and rearward directions of travel of said trailer; providing a fluid circuit having a motive fluid for effecting said steering in response to said detecting and for interconnecting said angle detecting and said steering via said circuit; providing a valve for controlling a direction of flow of said motive fluid; and controlling routing of said motive fluid through said circuit via said directional control valve and automatically according to each of said directions of travel so as to provide a particular sense of said wheel steering angle according to said direction of travel.

Claim 6

Dependent Claim 45 words

A method as in claim 3, and further comprising the steps of: providing that said wheel steering angle has the same sense as said articulation angle when said direction of travel is forward and is opposite in sense when said direction of travel is rearward.

Claim 7

Dependent Claim 36 words

A method as in claim 3, and further comprising the steps of: providing that a ratio of wheel steering angle to articulation angle is greater in magnitude for said rearward travel than for said forward travel.

Claim 8

Dependent Claim 70 words

A method as in claim 3, and further comprising the steps of: detecting speeds of travel of said trailer; setting a high set point speed of travel; and altering routing of said fluid via said valve when said direction of travel is forward and said high set point is detected so as to retain said wheels in a neutral mode of straight-away orientation at speeds above said high set point.

Claim 9

Dependent Claim 59 words

A method as in claim 6, and further comprising the steps of: setting a low set point speed of travel; and realtering routing of said fluid via said valve when said speed decreases and said low set point is detected so as to release said wheels from retention in said neutral mode at speeds below said low set point.

Claim 10

Dependent Claim 56 words

A method as in claim 7, and further comprising the steps of: providing that said high and low set points are set to speeds which are sufficiently different as to avoid constant cycling in and out of said neutral mode during a generally constant speed of travel of the trailer near either of said set points.

Claim 11

Independent Claim 195 words

An apparatus for steering the wheels of a two wheel trailer, and comprising: means for monitoring an angle of articulation in magnitude and sense between said trailer and a towing vehicle and generating articulation angle signals in response thereto; means for monitoring an angle of wheel steering in magnitude and sense relative to an axle of said trailer and generating wheel steering angle signals in response thereto; means for receiving said articulation angle signals and computing values of said articulation angle as a percentage of a range of articulation to either side of 0°; means for receiving said wheel steering angle signals and computing values of said wheel steering angle as a percentage of a range of steering to either side of 0°; means for comparing said articulation percentage values with said wheel steering percentage values and generating a correction signal whenever said articulation and wheel steering percentage values are not of equal magnitude; and means, responsive to said correction signal, for turning said wheels to adjust said wheel steering angle, whenever said articulation percentage value and said wheel steering percentage value are not equal in magnitude, in order to make said percentage values equal.

Claim 12

Independent Claim 195 words

An apparatus for steering the wheels of a two wheel trailer, and comprising: means for monitoring an angle of articulation in magnitude and sense between said trailer and a towing vehicle and generating articulation angle signals in response thereto; means for monitoring an angle of wheel steering in magnitude and sense relative to an axle of said trailer and generating wheel steering angle signals in response thereto; means for receiving said articulation angle signals and computing values of said articulation angle as a percentage of a range of articulation to either side of 0°; means for receiving said wheel steering angle signals and computing values of said wheel steering angle as a percentage of a range of steering to either side of 0°; means for comparing said articulation percentage values with said wheel steering percentage values and generating a correction signal whenever said articulation and wheel steering percentage values are not of equal magnitude; and means, responsive to said correction signal, for turning said wheels to adjust said wheel steering angle, whenever said articulation percentage value and said wheel steering percentage value are not equal in magnitude, in order to make said percentage values equal.

Claim 13

Dependent Claim 80 words

An apparatus as in claim 9, and further comprising: means for sensing transitions between forward and reverse modes of travel of said trailer; means for generating transition signals in response to said sensing; and for each of said transitions, means for changing said wheel steering angle, in response to said transition signals, from a pretransition angle other than 0° to a post-transition angle which is equal to said pretransition angle in magnitude and opposite to said pretransition angle in sense.

Claim 14

Independent Claim 141 words

An apparatus for steering the wheels of a two wheel trailer, and comprising: means for detecting an articulation angle between said trailer and a towing vehicle; means for steering said wheels by changing a wheel steering angle automatically according to changes in said articulation angle; means for identifying forward and rearward directions of travel of said trailer; a fluid circuit having a motive fluid for effecting said steering in response to said detecting and for interconnecting said angle detecting and said steering via said circuit; valve means for controlling a direction of flow of said motive fluid; and means for controlling routing of said motive fluid through said circuit via said valve means and automatically according to each of said directions of travel so as to provide a particular sense of said wheel steering angle according to said direction of travel.

Claim 15

Independent Claim 141 words

An apparatus for steering the wheels of a two wheel trailer, and comprising: means for detecting an articulation angle between said trailer and a towing vehicle; means for steering said wheels by changing a wheel steering angle automatically according to changes in said articulation angle; means for identifying forward and rearward directions of travel of said trailer; a fluid circuit having a motive fluid for effecting said steering in response to said detecting and for interconnecting said angle detecting and said steering via said circuit; valve means for controlling a direction of flow of said motive fluid; and means for controlling routing of said motive fluid through said circuit via said valve means and automatically according to each of said directions of travel so as to provide a particular sense of said wheel steering angle according to said direction of travel.

Claim 16

Dependent Claim 44 words

An apparatus as in claim 11, and further comprising: means for providing that said wheel steering angle has the same sense as said articulation angle when said direction of travel is forward and is opposite in sense when said direction of travel is rearward.

Claim 17

Dependent Claim 35 words

An apparatus as in claim 11, and further comprising: means for providing that a ratio of wheel steering angle to articulation angle is greater in magnitude for said rearward travel than for said forward travel.

Claim 18

Dependent Claim 74 words

An apparatus as in claim 11, and further comprising: means for detecting speeds of travel of said trailer; means for setting a high set point speed of travel; and means for altering routing of said fluid via said valve means when said direction of travel is forward and said high set point is detected so as to retain said wheels in a neutral mode of straight-away orientation at speeds above said high set point.

Claim 19

Dependent Claim 61 words

An apparatus as in claim 14, and further comprising: means for setting a low set point speed of travel; and means for realtering routing of said fluid via said valve means when said speed decreases and said low set point is detected so as to release said wheels from retention in said neutral mode at speeds below said low set point.

Claim 20

Dependent Claim 52 words

An apparatus as in claim 15, and further comprising: means for setting said high and low set points to speeds which are sufficiently different as to avoid constant cycling in and out of said neutral mode during a generally constant speed of travel of the trailer near either of said set points.

Claim 21

Independent Claim 95 words

An apparatus for steering the wheels of a two wheel trailer and comprising: means for attaching said trailer to a towing vehicle such that said trailer is pivotal above yaw, pitch, and roll axes; and means for converting movement of said trailer about said yaw axis into a motive force for said steering, said motive force being transmitted via a fluid; and means for controlling said steering in response to and according to forward and reverse directions for travel of said trailer in order to accomplish said steering in forward and reverse directions of travel.

Claim 22

Independent Claim 95 words

An apparatus for steering the wheels of a two wheel trailer and comprising: means for attaching said trailer to a towing vehicle such that said trailer is pivotal above yaw, pitch, and roll axes; and means for converting movement of said trailer about said yaw axis into a motive force for said steering, said motive force being transmitted via a fluid; and means for controlling said steering in response to and according to forward and reverse directions for travel of said trailer in order to accomplish said steering in forward and reverse directions of travel.

Claim 23

Dependent Claim 223 words

An apparatus as in claim 17, wherein said attaching means comprises: a generally standard draw bar and hitch ball on said towing vehicle having a nonpivotal yoke attached laterally and perpendicularly to said draw bar, said yoke having pins situated on each side of said ball and on said pitch axis which passes through a center of said ball; a tow bar attached at one end thereof to said trailer such that said trailer is rotatable about a longitudinal axis of said tow bar, said tow bar having a generally standard socket and latch at said other end for connection of said trailer to said hitch ball of said towing vehicle such that said longitudinal axis is coincident with said roll axis which passes through said center of said ball and said trailer is pivotal about said roll axis relative to said tow bar; and a first bar affixed to said tow bar near said one end and extending laterally of said tow bar, and a second bar attached to said socket and being pivotal about said yaw axis which passes through said center of said ball, said second bar having means engagable with said pins of said yoke such that said second bar pivots about said yaw axis in concert with said yoke and about said pitch axis relative to said yoke.

Claim 24

Dependent Claim 63 words

An apparatus as in claim 18, wherein said converting means comprises: actuator means attached to and extending between corresponding ends of said first and second bars and being pivotal relative to said second bar; steering means operatively attached to said wheels and interactive with said actuator means such that pivoting of said second bar is transferred to said wheels via said steering means.

Claim 25

Dependent Claim 60 words

An apparatus as in claim 19, and further comprising: a hydraulic circuit interconnecting said actuator means and said steering means, wherein said actuator means comprises hydraulic cylinders which expand and contract according to articulation of said trailer about said yaw axis and displace fluid of said hydraulic circuit to and from an hydraulic cylinder as part of said steering means.

Claim 26

Dependent Claim 57 words

An apparatus as in claim 17, wherein said controlling means comprises: flow control valve means for routing flow of said fluid according to said forward and reverse directions for travel of said trailer; and means for detecting and differentiating between forward and reverse directions of travel for said trailer and controlling said flow control valve means accordingly.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1996-09-13	1997-03-15	1997-09-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2000-09-13	2001-03-15	2001-09-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2004-09-13	2005-03-15	2005-09-14	$7700.00	Window Closed / Lapsed

Trailer and steerable wheels therefor

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