Power assist steering system

• US 6,189,648 B1
• Filed: 01/17/2000
• Issued: 02/20/2001
• Est. Priority Date: 07/25/1997
• Status: Expired due to Fees

• Current Assignee: Mtd Products Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Mtd Products Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Schaedler, Axel
• Primary Examiner(s): Hurley, Kevin
• Application Number:
  US09/483,843
• Time in Patent Office: 400 Days
• Field of Search: 180/417, 180/421, 180/422, 180/423, 180/430, 180/432, 913/75.R, 913/80, 914/44, 914/58
• US Class Current: 180/417
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/63 having cutters rotating about a vertical axis
• CPC Class Codes: A01D 34/69 with motor driven wheels
• CPC Class Codes: A01D 34/74 Cutting-height adjustment
• CPC Class Codes: B62D 5/06 fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
• CPC Class Codes: B62D 5/083 Rotary valves
• CPC Class Codes: B62D 5/16 Expansible chamber with flexible wall

Abstract

A power assist steering system is provided for use on a vehicle that has a steering implement and a steering mechanism operatively connected to a first wheel. The power assist steering system includes first and second vacuum actuators or a double acting vacuum actuator, vacuum source for providing a vacuum to the first and second vacuum actuators, a first disc powered relative to second disc for selectively activating the first and second vacuum actuators and a gear and gen plate for assisting the steering mechanism in turning the first wheel in first and second directions.

Claims

1. A riding mower, comprising:

a fame;

an engine operatively mounted to said frame, said engine having an intake manifold;

a first wheel rotatably and turnably connected to said frame;

a steering implement for use in turning said first wheel;

a steering mechanism operatively connected to said first wheel and said steering implement;

a power assist steering system including,

(1) a double acting vacuum actuator having

(a) an actuator body;

(b) a membrane forming first and second chambers

 

within said actuator body, said membrane being selectively movable within said actuator body;

(c) an actuator rod fixedly connected to said membrane and extending external to said actuator body, said membrane and said actuator rod moving in a first direction as a vacuum is established inside said first chamber, said membrane and said actuator rod moving in a second direction as a vacuum is established inside said second chamber;

(2) vacuum means for selectively providing a vacuum to said first and second chambers of said double acting vacuum actuator, said intake manifold providing said vacuum means;

(3) activating means for selectively activating said double acting vacuum actuator, said activating means having

(a) first and second switching means, said first switching means selectively initiating said membrane of said double acting vacuum actuator to move in said first direction, said second switching means selectively initiating said membrane of said double acting vacuum actuator to move in said second direction;

(b) a vacuum source line, said vacuum source line for use in communicating a vacuum from said intake manifold to said first and second switching means;

(c) first and second vacuum lines, said first vacuum line for use in communicating a vacuum from said first switching means to said first chamber of said double acting vacuum actuator, said second vacuum line for use in communicating a vacuum from said second switching means to said second chamber of said double acting vacuum actuator;

(d) a trigger segment having an extension with first and second ends, said trigger segment being selectively rotatable by said steering implement, said first end of said extension for selectively switching said first switching means, said second end of said extension for selectively switching said second switching means; and

,

(4) power assist means for assisting said steering mechanism, said power assist means having

(a) connecting means for use in selectively turning said first wheel in first and second directions, said connecting means being operatively connected to said actuator rod;

(b) a valve plate having a first side for use in supporting said first and second switching means, said valve plate being operatively connected to the steering mechanism, said valve plate having first and second stop bars for operative connection with said first and second ends of said extension of said trigger segment, said connecting means being pivotably connected to said first side of said valve plate.

2. A power assist steering system for use on a vehicle, the vehicle having a steering implement operatively connected to a steering mechanism that is operatively connected to a first wheel, said power assist steering system comprising:

a double acting vacuum actuator having a membrane that forms first and second chambers within said double acting vacuum actuator, said membrane being selectively movable within said actuator body;

vacuum means for selectively providing a vacuum to said first and second chambers of said double acting vacuum actuator;

activating means for selectively activating said double acting vacuum actuator, said activating means selectively initiating said membrane to move in first and second directions, said activating means having first and second switching means, said first switching means selectively initiating said membrane of said double acting vacuum actuator to move in said first direction, said second switching means selectively initiating said membrane of said double acting vacuum actuator to move in said second direction; and

,

power assist means for assisting the steering mechanism in turning the first wheel, said power assist means being operatively connected to said membrane of said double acting vacuum actuator.

3. A power assist steering system for use on a vehicle, the vehicle having a steering implement and a steering mechanism operatively connected to a first wheel, said power assist steering system comprising:

a first vacuum actuator;

vacuum means for providing a vacuum to said first vacuum actuator;

activating means for selectively activating said first vacuum actuator;

power-assist means for assisting the steering mechanism in turning the first wheel, said power assist means being operatively connected to said first vacuum actuator; and

a second vacuum actuator, said vacuum means providing a vacuum to said second vacuum actuator, said activating means selectively variably activating said second vacuum actuator, said first vacuum actuator for use with said power assist means in turning the first wheel in a first direction, said second vacuum actuator for use with said power assist means in turning the first wheel in a second direction.

4. The power assist steering system of claim 3 wherein said activating means further comprises:

a trigger segment having an extension with first and second ends, said trigger segment being selectively rotatable by the steering implement, said first end of said extension for selectively switching said first switching means, said second end of said extension for selectively switching said second switching means.

5. The power assist steering system of claim 3 wherein said power assist means comprises:

a valve plate having a first side for use in supporting said first and second switching means, said valve plate being operatively connected to the steering mechanism, said valve plate having first and second stop bars for operative connection with said first and second ends of said extension of said trigger segment.

6. A method of steering a vehicle with a power assist steering system, the vehicle comprising a steering implement and a steering mechanism, the power assist steering system comprising a vacuum actuator (40), vacuum means (24), activating means (50) and power assist means (60), the method comprising the steps of:

adjusting the steering implement (21) in a first direction;

rotating a trigger segment (34);

contacting a tip (27) of an air valve (38) with the trigger segment (34);

disconnecting the vacuum actuator 40 from the vacuum means (24);

removing the vacuum from the vacuum actuator (40);

activating the power assist means (60) with the vacuum actuator; and

,

assisting the steering mechanism (31) with steering the vehicle in the first direction.

7. The method of claim 6 wherein the step of disconnecting the vacuum actuator (40) from the vacuum means (24) comprises the step of:

closing the air valve (38).

8. The method of claim 7 wherein the step of removing the vacuum from the vacuum actuator (40) comprises the steps of:

drawing air in through holes (84) in the air valve (38);

drawing air through a vacuum line (45); and

,

drawing air into the vacuum actuator (40).

9. A method of steering a vehicle with a power assist steering system, the vehicle comprising a steering implement and a steering mechanism, the power assist steering system comprising a vacuum actuator (40), vacuum means (24), activating means (50) and power assist means (60), the method comprising the steps of:

adjusting the steering implement (21) in a first direction;

rotating a trigger segment (34);

contacting a tip (27) of an air valve (38) with the trigger segment (34);

closing the air valve (38);

drawing air in through holes (84) in the air valve (38);

drawing air through a vacuum line (45);

drawing air into the vacuum actuator (40);

forcing a portion (48) of the vacuum actuator (40) in a first direction (17);

forcing a connector link (42) in the first direction (17);

rotating a valve plate (35); and

,

assisting the steering mechanism (31) with steering the vehicle in the first direction.

10. The method of claim 9 wherein the step of assisting the steering mechanism (31) with steering the vehicle in the first direction comprises the step of:

moving the steering mechanism (31) with the valve plate (35).

11. A method of steering a vehicle with a power assist steering system, the vehicle comprising a steering implement and a steering mechanism, the power assist steering system comprising a vacuum actuator (40), vacuum means (24), activating means (50) and power assist means (60), the method comprising the steps of:

adjusting the steering implement (21) in a first direction;

activating the activating means (50) with the steering implement (21);

disconnecting the vacuum actuator 40 from the vacuum means (24);

removing the vacuum from the vacuum actuator (40);

activating the power assist means (60) with the vacuum actuator;

assisting the steering mechanism (31) with steering the vehicle in the first direction;

adjusting the steering implement (21) is a second direction;

reactivating the activating means (50) with the steering implement (21);

disconnecting a second vacuum actuator (41) from the vacuum means (24);

removing the vacuum from the second vacuum actuator (41);

activating the power assist means (60) with the second vacuum actuator (41); and

,

assisting the steering mechanism (31) with steering the vehicle in the second direction.

12. The method of claim 11 wherein the step of reactivating the activating means (50) with the steering implement (21) comprises the steps of:

counter rotating the trigger segment (34); and

,

contacting a tip (28) of a second air valve (39) with the trigger segment (34).

13. The method of claim 12 wherein the step of disconnecting the second vacuum actuator (41) from the vacuum means (24) comprises the step of:

closing the second air valve (39).

14. The method of claim 13 wherein the step of removing the vacuum from the second vacuum actuator (41) comprises the steps of:

drawing air in through holes (85) in the second air valve (39);

drawing air through a second vacuum line (46); and

,

drawing air into the second vacuum actuator (41).

15. The method of claim 14 wherein the step of activating the power assist means (60) with the second vacuum actuator (41) comprises the steps of:

forcing a portion (49) of the second vacuum actuator (41) in a first direction (19);

forcing a connector link (430 in the first direction (19); and

,

counter rotating the valve plate (35).

16. The method of claim 15 wherein the step of assisting the steering mechanism (31) with steering the vehicle in the second direction comprises the step of:

moving the steering mechanism (31) with the valve plate (35).

17. The method of claim 11 after the step of reactivating the activating means (50) with the steering implement (21), the method further comprising the steps of:

reconnecting the vacuum actuator (40) to the vacuum means (24);

restoring the vacuum to the vacuum actuator (40).

18. A method of steering a vehicle with a power assist steering system, the vehicle comprising a steering implement and a steering mechanism, the power assist steering system comprising a vacuum actuator (40), vacuum means (24), activating means (50) and power assist means (60), the method comprising the steps of:

adjusting the steering implement (21) in a first direction;

rotating a trigger segment (34);

closing an electric switch (54) with the trigger segment (34);

disconnecting the vacuum actuator 40 from the vacuum means (24);

removing the vacuum from the vacuum actuator (40);

activating the power assist means (60) with the vacuum actuator; and

,

assisting the steering mechanism (31) with steering the vehicle in the first direction.

19. The method of claim 18 wherein the step of disconnecting the vacuum actuator (40) from the vacuum means (24) comprises the step of:

closing a solenoid valve (56).

20. The method of claim 19 wherein the step of removing the vacuum from the vacuum actuator (40) comprises the steps of:

drawing air in through holes (62) in the solenoid valve (52);

drawing air through a vacuum line (45); and

,

drawing air into the vacuum actuator (40).