Vehicle suspension
First Claim
Patent Images
1. In an over the highway truck or tractor vehicle having tandem rear axles one of which is a driven axle and the other is a tag axle the improvement comprising:
- a. at least one driven axle fluid spring and at least one tag axle fluid spring, the springs respectively being interposed between the driven and tag axles and a vehicle frame;
b. a supply of fluid under pressure;
c. conduits connecting the supply to the springs;
d. pressure control means connected to at least one of the conduits for normally maintaining a predetermined pressure ratio between the pressure in the at least one driven axle spring and the at least one tag axle spring; and
,e. an operator actuatable traction enhancement control for selectively altering said predetermined ratio to provide a relative increase of the pressure in the at least one driven axle spring relative to the pressure in the at least one tag axle spring.
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Accused Products
Abstract
An over the highway truck or tractor suspension with traction enhancement. Air springs are provided for the rear axles of a 2×6 vehicle. Normally the load is evenly divided between driven and tag axles. When enhanced traction is desired, the tag axle springs are communicated with an auxiliary tank to reduce pressure in them while air under pressure is supplied to the driven axle springs to increase the pressure in them and thereby increase the portion of the load on the driven axle to provide enhanced traction.
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Citations
31 Claims
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1. In an over the highway truck or tractor vehicle having tandem rear axles one of which is a driven axle and the other is a tag axle the improvement comprising:
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a. at least one driven axle fluid spring and at least one tag axle fluid spring, the springs respectively being interposed between the driven and tag axles and a vehicle frame; b. a supply of fluid under pressure; c. conduits connecting the supply to the springs; d. pressure control means connected to at least one of the conduits for normally maintaining a predetermined pressure ratio between the pressure in the at least one driven axle spring and the at least one tag axle spring; and
,e. an operator actuatable traction enhancement control for selectively altering said predetermined ratio to provide a relative increase of the pressure in the at least one driven axle spring relative to the pressure in the at least one tag axle spring. - View Dependent Claims (2, 3, 4)
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5. In an over the highway haul vehicle having driven and non driven wheels, an improved suspension comprising:
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a. a first pair of air springs interposed between the driven wheels and a vehicle frame to provide driven wheel support for the vehicle; b. a second pair of air springs interposed between the non driven wheels and the frame to provide non driven wheel support for the vehicle; c. a supply of air under pressure; d. an air pressure communicating means for supplying air under pressure from the supply to the springs and substantially maintain predetermined relative pressures in the first springs relative to the second during normal operation; and
,e. selectively actuatable means for reducing pressure in the second springs relative to the first including means selectively to increase the pressure in the first springs. - View Dependent Claims (6, 7, 8, 9)
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10. A haul vehicle comprising:
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a. a frame; b driven and tag axles connected to the frame; c. pairs of driven and tag axle air springs respectively interposed between the driven and tag axles and the frame; d. a supply of compressed air; and
,e. an air supply system connecting the supply to the springs, the system including; i. a height valve connected to the springs and responsive to vertical relative movement of the frame and axles for controlling pressure in at least the driven axle springs thereby to maintain the height of the vehicle frame within a predetermined range; and
,ii. an operator actuatable axle differential control valve operatively connected to the tag axle spring, the differential control valve having a traction enhancement position wherein a signal is transmitted to alter the supply of air under pressure from the height valve to the tag axle springs and to permit the flow of air from the tag axle springs whereby to reduce pressure in the tag axle springs. - View Dependent Claims (11, 12, 13)
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14. A haul vehicle comprising:
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a. a frame; b. a driven rear axle connected to the frame; c. a tag rear axle connected to the frame; d. a pair of driven axle air springs interposed between the driven axle and the frame; e. a pair of tag axle air springs interposed between the tag axle and the frame; f. a supply of compressed air; and
,g. an air supply system connecting the supply to the springs, the system including; i. an auxiliary air tank; ii. a traction control valve coupled to the tag axle springs, the traction control valve also being connected to the auxiliary tank; and
,iii. an operator actuatable axle differential control valve operatively connected to the traction control valve, the differential control valve having a traction enhancement position wherein a signal is transmitted to the traction control valve to alter the supply of air under pressure to the tag axle springs and to couple the tag axle springs to the auxiliary tank whereby to reduce pressure in the tag axle springs. - View Dependent Claims (15, 16)
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17. A haul vehicle comprising:
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a. a frame; b. a driven rear axle connected to the frame; c. a tag rear axle connected to the frame;
interposed between the driven axle and the frame;e. a pair of tag axle air springs interposed between the tag axle and the frame; f. a supply of compressed air; and
,g. an air supply system connecting the supply to the springs, the system comprising; i. a height valve connected to the supply and to the springs and responsive to vertical relative movement of the frame and axle for controlling pressure in at least the driven axle springs thereby to maintain the height of the vehicle frame within a predetermined range; ii. an auxiliary air tank; iii. a traction control valve coupled to the height valve output between the height valve and the tag axle springs, the traction control valve also being connected to the auxiliary tank; and
,iv. an operator actuatable axle differential control valve operatively connected to the traction control valve, the differential control valve having a traction enhancement position wherein a signal is transmitted to the traction control valve to cause the latter to stop the supply of air under pressure from the height valve to the tag axle springs and to couple the tag axle springs to the auxiliary tank whereby to reduce pressure in the tag axle springs. - View Dependent Claims (18, 19)
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20. A haul vehicle comprising:
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a. a frame; b. a pair of front steerable wheels connected to the frame; c. a driven rear axle connected to the frame; d. a tag rear axle connected to the frame; e. a pair of driven axle air springs interposed between the driven axle and the frame; f. a pair of tag axle air springs interposed between the tag axle and the frame; g. a supply of compressed air; and
,h. an air supply system connecting the supply to the springs, the system comprising; i. a height valve responsive to vertical relative movement of the frame and axles for controlling pressure in at least the driven axle springs thereby to maintain the height of the vehicle frame within a predetermined range; ii. a height valve supply conduit connected to the supply and the height valve for delivering air under pressure from the supply to the height valve; iii. a height valve output conduit connected to the height valve and the springs for delivering air under pressure from the height valve to the springs; iv. an auxiliary air tank; v. a traction control pilot valve coupled to a branch of the height valve output conduit between the height valve and the tag axle springs, the traction control pilot valve also being connected to the auxiliary tank by an auxiliary tank conduit; and vi. an operator actuatable axle differential control valve operatively connected to the traction control pilot valve, the differential control valve having a traction enhancement position wherein a signal is transmitted to the traction control pilot valve to cause the latter to stop the supply of air under press from the height valve to the tag axle springs and to couple the tag axle springs to the auxiliary tank through a tank conduit whereby to reduce pressure in the tag axle springs. - View Dependent Claims (21, 22)
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23. A vehicle comprising:
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a. a longitudinally extending frame having front and rear portions; b. steerable wheels connected to the front portion; c. driven and tag axles connected to the rear portion and respectively carrying driven and non-driven wheels; d. driven and tag axle air springs respectively interposed between the frame and the driven and tag axles; e. a supply connected to the springs by a conduit and valving system including valve means for maintaining a predetermined pressure ratio in the springs during normal operation; and
,f. the system including an operator controlled traction enhancement subsystem for selectively enhancing driven wheel traction under special conditions and including ratio changing means for changing the pressure ratio to increase the portion of a load supported by the driven axle while concurrently maintaining the vehicle in a predetermined height range irrespective of the total load imposed on the vehicle wheels. - View Dependent Claims (24, 25, 26)
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27. A vehicle comprising:
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a. a longitudinally extending frame having front and rear portions; b. steerable wheels connected to the front portion; c. driven and tag axles connected to the rear portion and respectively carrying driven and nondriven wheels; d. driven and tag axle air springs respectively interposed between the frame and the driven and tag axles; e. a supply connected to the springs by a conduit and valving system including valve means for maintaining a predetermined pressure ratio in the springs during normal operation; f. the system including an operator controlled traction enhancement subsystem for selectively enhancing driven wheel traction under special conditions and including ratio changing means for changing the pressure ratio to increase the portion of a load supported by the driven axle; and
,g. the ratio changing means including structure defining a plenum and valve means for selectively communicating the tag axle springs with the plenum for traction enhanced operation whereby to expand the volume for containment of a quantity of air in the tag axle springs during normal operation to reduce the pressure of such known quantity in a predetermined ratio.
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28. A method of operating a vehicle having driven and tag axles and driven and tag axle fluid springs respectively interposed between the driven and tag axles and a vehicle frame comprising:
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a. operating a height valve to communicate a supply of air under pressure with the springs during normal operation to maintain a predetermined normal operation pressure ratio between the driven and tag axle springs; b. actuating a traction enhancement control when enhanced traction is desired to communicate the tag axle springs and a plenum thereby expanding the volume containing the quantity of air in the tag axle springs to increase with an attendant and concurrent predetermined reduction in the pressure of such quantity; and c. returning the traction enhancement control to its preactuation condition to terminate communication with the plenum and substantially concurrently establishing communication between the tag axle springs and the supply of air under pressure. - View Dependent Claims (29, 30, 31)
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Specification