DETAILED DESCRIPTION OF AT LEAST ONE PREFERRED EMBODIMENT

[0078] FIG. 1 illustrates a preferred embodiment of a seat suspension 40 of the invention that has a seat platform 42 and a base or ground 44 between which is disposed a linkage arrangement 46 and a suspension cartridge 48 . The suspension cartridge 48 is of self-contained and modular construction to facilitate assembly and installation. The suspension cartridge 48 preferably is equipped with at least one outwardly extending arm 50 that carries a roller 52 . The suspension cartridge 48 absorbs energy while providing at least weight adjustment capability. In the preferred embodiment shown in FIG. 1 , the suspension cartridge 48 provides both height and weight adjustment capabilities. In the preferred embodiment shown in FIG. 1 , the roller 52 cooperates with a contoured cam 54 during suspension operation.

[0079] In the preferred seat suspension embodiment shown in FIG. 1 , the linkage arrangement 46 preferably comprises a scissors linkage arrangement, but is not intended to be limited to a scissors linkage arrangement. For example, the linkage arrangement 46 can be a four-bar linkage arrangement, a scissors linkage arrangement, or another type of linkage arrangement, if desired.

[0080] The linkage arrangement 46 includes a pair of spaced apart inner arms 43 each of which is pivotally attached to a corresponding one of a pair of spaced apart outer arms 45 . At or adjacent one end of each arm is an axle 47 that rotatively receives a roller 49 . In a currently preferred embodiment, the platform axle (not shown) is generally U-shaped so as to clear the suspension cartridge 48 . Such a U-shaped platform axle advantageously also preferably can simultaneously function as a torsion bar. Each roller 49 rides in a track 51 . For example, in the preferred embodiment shown in FIG. 1 , the platform 42 and base 44 have side walls 53 each equipped with an inturned lip 55 that each defines a roller-receiving track 51 . At or adjacent the other end of each arm 43 and 45 is an anchor rod 57 that extends therebetween to pivotally anchor the linkage arrangement 46 .

[0081] FIGS. 2 and 3 depict a preferred embodiment of the suspension cartridge 48 of the invention. The cartridge 48 includes a cartridge housing 56 that can be of substantially tubular construction for providing strength and imparting structural rigidity to the cartridge. The housing 56 has a front wall 58 , a fore-aft extending end wall 60 , and a pair of sidewalls 62 and 64 that each can be equipped with a fore-aft extending ear 90 . In the preferred embodiment shown in FIGS. 2 and 3 , both cartridge housing sidewalls 62 and 64 are identical to each other as they are both equipped with a biasing element hanger receiving slot 66 and a clearance notch 68 in which a biasing element retainer shaft 70 is disposed.

[0082] The suspension cartridge 48 includes at least one biasing element 72 that opposes suspension collapse and absorbs energy during suspension operation. In the preferred embodiment shown in FIGS. 2 and 3 , the cartridge 48 has a plurality of biasing elements 72 . Preferably, each biasing element 72 is a coil spring 73 that is releasably captured in tension. If desired, the suspension cartridge 48 can be configured so as to capture each biasing element in a state of compression.

[0083] Each biasing element 72 has one end operably coupled to part of the biasing element retainer shaft 70 and has its other end operably coupled to part of a biasing element hanger assembly 74 . The biasing element retainer shaft 70 preferably comprises a generally cylindrical shaft that has a generally circular cross-section. To facilitate relative movement between each biasing element 72 and shaft 70 , there is a bearing 76 disposed therebetween. Referring particularly to FIG. 3 , the biasing element hanger assembly 74 is made of a plurality of components that includes at least one biasing element carrying yoke 75 .

[0084] The biasing element retainer shaft 70 extends through a pair of bores 78 in a suspension arm linkage arrangement 80 that preferably comprises a bell crank arm linkage arrangement. Referring more specifically to FIG. 3 , the bell crank arm linkage arrangement 80 includes a pair of generally parallel and generally triangular bell crank arms 82 that are spaced apart by a hollow bearing tube 84 . The bearing tube 84 preferably is fixed to each bell crank arm 82 , such as by a weld or the like. To pivotally anchor the bell crank arm linkage arrangement 80 to the cartridge housing 56 , a pivot shaft 86 received through the tube 84 extends through a bore 88 in each cage sidewall ear 90 . To prevent the shaft from disengaging, an anchor arrangement 92 is attached to each end of the shaft 86 . To facilitate relative rotation between the shaft 86 and the cartridge housing 56 as well as the bell crank arm linkage arrangement 80 , each shaft end preferably is equipped with a bearing 94 that can be of tubular or cylindrical construction. In the preferred embodiment shown in FIG. 3 , each shaft anchor 92 comprises a clip that can be an E-shaped clip or the like. Where the bell crank pivot shaft 86 is also equipped with bearings 94 , each bearing 94 is made of a suitable low friction material.

[0085] To help dissipate energy, including vibrational energy, the suspension cartridge 48 preferably includes a damper 96 that can be a shock absorber or the like. Preferably, the damper 96 comprises a piston and cylinder arrangement whereby the piston is reciprocably received by the cylinder. If desired, other types of dampers can be used.

[0086] In the preferred embodiment shown in more detail in FIG. 3 , the damper 96 has a cylindrical housing 98 from which a piston 100 reciprocably extends. The piston 100 has a mount 102 at its free end that receives a damper mounting shaft 104 that extends through a bore 106 in at least one of the bell crank arms 82 . Preferably, the shaft extends through the bore 106 in both arms 82 with the damper 96 disposed between the arms 82 . The damper housing 98 has a mount 108 at its free end which receives a pivot 110 that cantilevers outwardly from a bracket 112 attached by rivets 114 to an interior surface of cartridge housing end wall 60 . Anchors, such as C-clips, E-clips, or the like, preferably are used to keep each damper mount pivotally engaged with its respective mounting shaft and mounting pivot.

[0087] Each bell crank arm 82 has another bore 116 that receives an axle shaft 118 that extends through the roller 52 , which comprises a wheel 120 in FIGS. 2 and 3 . The axle shaft 118 preferably extends through the bore 116 in each bell crank arm 82 such that the roller 52 is positioned between each arm 82 . To prevent the shaft 118 from moving in an axial direction, anchors, such as C-clips, E-clips, or the like, are preferably used.

[0088] The suspension cartridge arrangement 48 also includes a height and weight adjust assembly 122 . The height and weight adjust assembly 122 includes a weight adjust knob 124 that is manipulable by a seat occupant when the seat occupant desires to vary an amount of preload applied to each biasing element 72 . The assembly 122 preferably also includes a height adjust knob 126 that is also manipulable by a seat occupant when the seat occupant wishes to change seat height. In the preferred embodiment shown in more detail in FIG. 3 , both knobs 124 and 126 are rotatable. If desired, one or both knobs can be manipulated in another manner to achieve the respective desired effect.

[0089] Both knobs 124 and 126 are substantially coaxial with an adjuster rod 128 that extends through a port 130 in the cartridge housing front wall 58 and which preferably is substantially disposed inside the cartridge housing 56 between its sidewalls 62 and 64 . The adjuster rod 128 is received through a guide 132 , such as a nut that preferably is a barrel nut. In a preferred embodiment, the barrel nut 132 is captured between a pair of spring hanger yokes 75 in the manner depicted in FIG. 3 . A pair of rivets 134 preferably fixes one of the spring hanger yokes 75 to the other one of the spring hanger yokes 75 .

[0090] If desired, the rod 128 can carry a limiter 136 that limits travel of the barrel nut 132 relative to the rod 128 during suspension operation. In the preferred embodiment shown in FIGS. 2 and 3 , the limiter 136 is a pin that is disposed in the rod 128 generally perpendicular to the longitudinal axis of the rod 128 . In the preferred embodiment shown in FIGS. 2 and 3 , a portion of the rod 128 is threaded 138 , the threaded portion 138 is threadably received through the barrel nut 132 , and the rod can rotate in either direction until the limiter 136 bears against the barrel nut 132 .

[0091] The end of the adjuster rod 128 is received in a pocket 139 in one end of a fore-aft extending adjuster brace 140 that is coupled at its other end by a mount 142 to the biasing element retainer shaft 70 . In one preferred embodiment, the mount 142 comprises a head with a notched opening therein that is constructed and arranged to clip onto the shaft 70 . In another preferred embodiment, the mount 142 can comprise a head that has a bore that extends transversely therethrough in which the shaft 70 is received. The brace 140 preferably is disposed inside the cartridge housing 56 such that it extends in a fore-aft direction between sidewalls 62 and 64 and lies adjacent end wall 60 .

[0092] In the preferred embodiment shown in FIGS. 2 and 3 , a pin 144 fixes the weight adjust knob 124 to the adjuster rod 128 such that the knob 124 and rod 128 rotate in unison when the knob 124 is turned. A bearing disk 146 is disposed between the weight adjust knob 124 and the height adjust knob 126 to facilitate relative rotation therebetween. The height adjust knob 126 has a threaded stem 148 that extends outwardly therefrom which is threadably received in a threaded plug 150 that is seated either in the cartridge housing port 130 or a in slot (not shown) in the seat platform 42 .

[0093] Rotation of the weight adjust knob 124 rotates the adjuster rod 128 in a corresponding direction. Rotation of the adjuster rod 128 causes the distance between the barrel nut 132 and biasing element retainer shaft 70 to change, which in turn changes biasing element tension. Changing biasing element tension increases or decreases biasing element preload, this in turn affects how the suspension accommodates a seat occupant of a particular weight as well as the nature of suspension energy absorption. Rotation of the height adjust knob 126 moves the adjuster rod 128 , barrel nut 132 , spring hanger assembly 74 , and biasing element retainer shaft 70 in unison, causing a rotation of the bell crank 80 about pivot 84 , which changes the distance between the seat platform 42 and the base 44 . Changing the distance between the platform 42 and the base 44 changes the height of a seat mounted on the platform 42 relative to the base 44 .

[0094] Weight adjustment effected by turning the weight adjust knob preferably does not affect seat height such that weight adjustment is substantially independent of height adjustment. Conversely, height adjustment effected by turning the height adjust knob preferably does not change the resistance of the suspension cartridge to a load applied thereto such that height adjustment is substantially independent of weight adjustment and vice versa.

[0095] In the preferred embodiment shown in FIG. 4 , the suspension cartridge arrangement 48 has a single suspension arm 50 ′ that can be made of a plurality of bell crank arm plates 82 , which preferably are fixed together. If desired, the arm 50 ′ can be made of a single plate. The arm 50 ′ also carries a damper 96 , which has one end attached to axle shaft 118 and its other end attached to a pivot pin 152 that preferably cantilevers outwardly from an interior surface of one of the cartridge housing sidewalls 62 . As is shown in FIG. 4 , the roller 52 is a wheel 120 that is rotatively carried by axle shaft 118 between damper mount 102 and bell crank arm 50 ′.

[0096] Referring additionally to FIG. 5 , each biasing element 72 has one end 154 that extends around a bearing clip 156 that is disposed between it and the biasing element retainer shaft 70 . Each bearing clip 156 helps communicate and more uniformly distribute biasing element forces during suspension operation such that friction between the corresponding biasing element 72 and the retainer shaft 70 is reduced. Referring additionally to FIGS. 5 and 6 , each clip 156 is generally C-shaped such that it encompasses an angular extent around the retainer shaft 70 of at least 180° and preferably at least about 190°. In the preferred embodiment shown in FIG. 5 , the biasing element mount 154 is a hook 158 and the retainer shaft 70 is a solid shaft of circular cross section that has a circumferentially extending groove 160 ( FIG. 9 ) in its outer periphery where the bearing clip 156 seats.

[0097] FIG. 6 illustrates the bearing clip 156 in more detail. The clip 156 has a body 162 that has a flat but arcuate inner surface 164 and a concave and arcuate outer surface 166 . The outer surface 166 has a ridge 168 and 170 along each side that defines a circumferentially extending hook receiving channel 172 therebetween. To facilitate assembly onto retainer shaft 70 , the inner bearing clip surface 164 has a pair of outwardly opening flats 174 and 176 that collectively define a shaft-receiving mouth 178 . In assembly, there is at least a slight interference fit between the bearing clip 156 and the shaft 70 such that the clip 156 preferably snaps onto the shaft 70 . Therefore, the clip 156 preferably is self-retaining on the shaft 70 upon assembly permitting the shaft 70 and both bearing clips 156 to be assembled and shipped as a unit, if desired.

[0098] Each bearing clip preferably is made of a durable and resilient material that is long-lasting and tough. One such preferred material is plastic, namely nylon. Such a material preferably flexes at least slightly to enable a snap fit to be provided between the clip 156 and the shaft 70 .

[0099] FIGS. 7 - 9 illustrate another preferred embodiment of a suspension cartridge arrangement 48 ′ of the invention. The suspension cartridge 48 ′ has a housing 56 ′ that is of substantially tubular construction and which has shaft receiving notches 68 and 180 and at one end and an end cap 182 at the other end that has a threaded bore 184 therein (FIG. 9 ) that threadably receives the threaded stem 148 of the weight adjust knob 124 .

[0100] Referring more particularly to FIG. 8 , the adjuster rod 128 is attached by a shaft coupling assembly 188 to a reciprocable piston 100 of the damper, which is disposed within the cartridge housing 56 ′. The shaft coupling assembly 188 includes a coupling tube or sleeve 200 that has a plurality of spaced apart bores that each receives one end of a coupling wire 202 . One coupling wire end extends through one of the bores in the coupling tube 200 and into a complementary bore in the adjuster rod 128 . The other coupling wire end extends through the other one of the bores in the coupling tube 200 and into a complementary bore in the damper piston 100 . Opposite and in between the coupling wire ends is a curved loop of wire that is also circumferentially contoured so as to bear against an engaged the coupling tube 200 and a manner that helps retain the coupling wire ends in their respective bores.

[0101] The damper housing 98 is attached at its free end by at least one coupling bracket and clip assembly 190 to the biasing element retainer shaft 70 . The end of the damper housing 98 is attached by a clip 206 to a generally U-shaped coupling bracket 204 that is fixed, such as by welding, to part of the biasing element retainer shaft 70 . The coupling bracket 204 has a pair of spaced apart arms, one of which has an aperture therethrough. The clip 206 goes over shaft 70 before the damper 96 is attached to the clip 206 by snap fitting the clip into bracket arm aperture 207 .

[0102] The roller 52 ′ comprises a truncated roller 192 that can ride back-and-forth during suspension operation. In a currently preferred embodiment, the truncated roller 192 rides along a cam 54 that is upraised from the base 44 .

[0103] Referring more particularly to FIG. 9 , the end cap 182 is a generally square or rectangular piece of material that seats in one end 194 of the cartridge housing 56 ′. The end cap 182 has a cartridge housing seating groove 196 about its periphery that receives the exterior edge 198 of the cartridge housing 56 ′. The threaded bore 184 preferably is generally centrally located relative to the outer edges of the end cap 182 . In the preferred embodiment shown in FIG. 9 , the end cap 182 is made of a metallic material, such as sintered powder metal.

[0104] Referring additionally to FIG. 10 , the cartridge housing 56 ′ includes a pair of spaced apart and substantially identical sidewalls 62 ′ and 64 ′. To permit sideways insertion of the hanger assembly 74 , at least one hanger receiving slot 66 includes a barrel nut clearance notch 208 to facilitate assembly of the hanger assembly 74 to the cartridge housing 56 ′. Such an arrangement permits the hanger assembly 74 to be assembled as a unit to the cartridge housing 56 ′. For example, the hanger assembly 74 is slid sideways into one of the slots with the barrel nut 132 sliding through clearance notch 208 .

[0105] To help improve strength and increase structural rigidity, each sidewall 62 ′ and 64 ′ terminates in an inturned flange 210 and 212 . As is shown in FIG. 10 , each flange 210 and 212 underlies part of the hanger assembly 74 . In the preferred embodiment shown in FIG. 10 , each flange 210 and 212 has a forward edge 214 and 216 that preferably each engages or bears against the end cap 182 . In the preferred embodiment shown in FIG. 10 , the forward edge of each flange 210 and 212 is received in part of the end cap seating groove 196 . While each inturned flange 210 and 212 can extend substantially the entire length of its corresponding sidewall, each flange 210 and 212 preferably terminates at or adjacent its corresponding sidewall ear 90 ′.

[0106] Each sidewall ear 90 ′ includes a biasing element retainer shaft receiving notch 68 that is defined by at least one curved shaft guide edge 218 that can help guide movement of the biasing element retainer shaft 70 during suspension operation. In the preferred embodiment shown in FIG. 10 , however, each guide edge 218 preferably provides clearance so as not to interfere with movement of the biasing element retainer shaft 70 . To prevent withdrawal of the biasing element retainer shaft 70 from the notch 68 , the lower portion of the notch 68 is defined by a retainer lip 220 . In the preferred embodiment shown in FIG. 10 , each retainer lip 220 is shaped like a tooth.

[0107] Each sidewall ear 90 ′ also includes a pivot shaft receiving notch 88 ′ in which the pivot shaft 86 is disposed. In the preferred embodiment shown in FIG. 10 , each notch 88 ′ preferably is generally U-shaped such that has a pair of notch side edges 222 and 224 that both extend in a generally fore-aft direction.

[0108] These notches 68 and 88 ′ help facilitate assembly because they permit suspension components of the suspension cartridge to be assembled from the rear of the cartridge housing 56 ′ without the need for clips or fasteners for retaining the suspension components. For example, in the preferred embodiment shown in FIG. 10 , notches 68 and 88 ′ respectively receive and help retain biasing element retainer shaft 70 and suspension arm linkage pivot shaft 86 during assembly and during suspension operation. Where the suspension arm linkage arrangement comprises a bell crank suspension arm linkage arrangement 80 , notches 68 and 88 ′ respectively receive and help retain the biasing element retainer shaft 70 and the suspension arm linkage pivot shaft 86 during assembly and during suspension operation. During suspension operation, biasing element tension helps keep the retainer shaft 70 and the pivot shaft 86 seated in their respective notches.

[0109] FIG. 11 illustrates in more detail a preferred embodiment of the suspension arm linkage arrangement 80 that preferably is a bell crank arm linkage arrangement 226 . The suspension arm linkage arrangement 226 includes a pair of arms 82 ′, each of which is a plate preferably formed of metal. An example of a preferred method of making each arm 82 ′ is by stamping or punching.

[0110] Each arm 82 ′ has a plurality of bores formed therein, preferably formed at the same time that the rest of the arm 82 ′ is formed. One of the bores 228 is a round hole formed in each arm 82 ′ that is constructed and arranged to receive and retain the biasing element retainer shaft 70 . Another one of the bores 230 is a round hole formed in each arm that is constructed and arranged to receive and retain the pivot shaft 86 . A still further one of the bores 232 is a round hole formed in each arm that is constructed and arranged to receive and retain the axle shaft 118 . In the preferred embodiment shown in FIG. 11 , bore 232 is carried by a tab 234 that extends outwardly from the arm 82 ′. Part of the tab 234 is defined by a stop notch 236 that has an abutment surface 238 against which part of roller 52 bears during suspension operation to prevent roller over travel or over rotation. Another part of the tab 235 defines an abutment 239 in the opposite direction.

[0111] The biasing element retainer shaft 70 is equipped with a pair of spaced apart bearing seats 160 that each preferably comprises a groove or channel 160 formed in the shaft 70 adjacent one end of the shaft. As a result of each shaft end having such a groove or channel 160 , each axial shaft end comprises a retainer head 240 that prevents a biasing element bearing 156 seated in the groove or channel 160 from moving axially relative to the shaft 70 . To prevent the biasing element retainer shaft 70 from sliding axially relative to either arm 82 ′, the shaft can be anchored by a ring 242 that can be a weld or another adhesively applied ring. In one preferred embodiment, the ring 242 is a weld that fixes the biasing element retainer shaft 70 to at least one of the bell crank arms 82 ′. In another preferred embodiment, the ring 242 is fixed to the retainer shaft 70 but not to any bell crank arm 82 ′. Such an arrangement limits axial movement of the retainer shaft 70 relative to one or both bell crank arms 82 ′.

[0112] The bell crank arms 82 ′ are fixed to the pivot shaft 86 . Each end of the pivot shaft 86 has a diametrically necked down portion 244 that each receives a bearing 94 ( FIG. 7 ) that is, in turn, received in a notch 88 ′ ( FIGS. 9 and 10 ) in sidewall ear 90 ′. Each bearing 94 permits the pivot shaft 86 to rotate relative to the cartridge housing 56 ′ during suspension operation.

[0113] The axle shaft 118 is attached to each bell crank arm 82 ′, preferably with retaining clips or the like. For example, the axle shaft 118 that is shown in FIG. 11 has a groove 246 at each end that receives a clip or ring. For example, in one preferred embodiment, a C-clip or E-clip is used. Where retainer ring or clip is used (not shown in FIG. 11 ), each such ring or clip is disposed outwardly of a corresponding adjacent bell crank arm 82 ′.

[0114] FIG. 12 illustrates a truncated roller cam and follower arrangement 248 of the invention. The cam and follower arrangement 248 includes a follower roller 52 ′ that preferably is a truncated roller 192 that can roll back and forth in response to the suspension collapsing and expanding during suspension operation. The cam and follower arrangement 248 also includes a cam 54 that preferably is a ramp 250 that has a cam surface 252 that can be contoured in a manner that affects the load-deflection curve of the suspension. Although the preferred suspension embodiment depicted in FIGS. 7 - 12 employs a truncated roller 192 , the suspension arrangement of the invention can also be used with a roller 52 that is a circular wheel that rides along the cam.

[0115] The truncated roller 192 has a body 254 with a plurality of tangs 256 that each extend outwardly from the body to help prevent truncated roller over rotation. Each tang 256 preferably extends outwardly from an arm 258 that, in turn, extends outwardly from the truncated roller body 254 . Preferably, there are two pairs of such arms 258 with one pair of arms 258 extending outwardly in one direction and the other pair of arms 258 5 extending outwardly in another direction. Each pair of arms carry a flat 260 and 262 that is capable of sliding relative to the cam when the flat is in contact with the cam. The region between the flats 260 and 262 defines an outer profile 264 that preferably is arcuately contoured so as to, for example, produce a semi-circular contour. This arcuately contoured outer profile 264 is in rolling contact with the cam 54 during suspension operation.

[0116] The truncated roller 192 has a spindle or hub 266 that receives axle shaft 118 . The hub 266 preferably is generally cylindrical and comprise a bearing, if desired. The hub 266 preferably is integrally formed as part of the truncated roller body 254 .

[0117] The truncated roller body 254 has a pair of sidewalls 268 and 270 that each includes an outwardly extending over rotation preventing boss 272 , only one of which is shown in FIG. 12 . As the truncated roller 192 rotates during suspension operation, the roller behaves as a conventional roller unless and until, through for example some rare unloaded event, the roller 192 gets out of sync with the cam 54 . If an out of sync condition occurs, one of the flats comes into contact with the cam 54 and re-indexes the truncated roller 192 relative to the cam such that part of the arcuately contoured outer profile goes back into contact with the cam 54 . During re-indexing, sliding contact can occur between one of the flats and the cam 54 .

[0118] Each boss 272 also helps prevent the roller 192 from getting out of sync with the cam 54 . One or both bosses 272 engages a corresponding abutment surface only as a redundant follower rotation limit, which is not intended to occur during normal suspension operation. For example, during assembly, each boss 272 can engage an abutment surface to prevent improper orientation of the truncated roller 192 from occurring.

[0119] The truncated roller 192 has a contact surface that includes each flat 260 and 262 and the outer profile 264 between the flats. The contoured outer profile comprises a partial circumference that is at least great enough to permit the roller to pivot about the axle shaft 118 throughout the entire suspension travel. In other words, the developed length of the arcuately contoured outer contact surface is at least greater than the length of that portion of the cam contact surface with which the outer contact surface comes into contact during full suspension travel.

[0120] In one preferred embodiment, this contact surface preferably encompasses an angular extent of at least 30°. In one preferred embodiment, the truncated roller contact surface encompasses an angular extent of between 30° and 270°. As a result of this configuration, the truncated roller 192 has a larger effective radius than a round roller of a similar overall height. This advantageously reduces friction, increases robustness, and improves durability, all without substantially increasing cost.

[0121] In one preferred embodiment, the truncated roller contact surface has an effective radius of at least about 15 mm and no more than about 50 mm. In a currently preferred embodiment, the truncated roller contact surface has an effective radius of about 26 mm In this same preferred embodiment, the outer profile 264 of the contact surface has a width that is at least about 26 mm. The truncated roller 192 is made of a durable, resilient, and long-lasting elastomeric material that preferably is acetal. If desired, other materials, such as plastic, metal, alloyed steel, or the like, can be used.

[0122] The cam 54 has a bottom 274 , a top 252 , a pair of sidewalls 276 and 278 , and a rear wall 280 . The top surface 252 is the cam surface upon which the roller rides during suspension operation. In the preferred embodiment shown in FIG. 12 , the cam surface 252 is substantially smooth and substantially straight so as to impart a substantially linear load deflection curve to the suspension. If desired, the cam surface 252 can deviate from being straight to provide a load deflection curve that is nonlinear. For example, the cam surface can be curved so as to provide a curvilinear load deflection curve. In another example, the cam surface can have a first portion that is substantially straight and a second portion that is generally curvilinear where needed. Other variations are possible.

[0123] The cam 54 preferably is fixed to the base or the ground. In the preferred cam embodiment shown in FIG. 12 , the bottom 274 of the cam has an outwardly protruding boss 282 that is received in a corresponding bore (not shown) in the suspension base. To further anchor the cam 54 , the cam 54 has a bore 284 that is constructed and arranged to receive a fastener, such as a screw, a bolt, or the like, that extends through a bore (not shown) in the suspension base and into the cam bore 284 . If desired, an adhesive can also be used with or without one or more fasteners in anchoring the cam to the suspension base.

[0124] The cam 54 preferably has a height at its highest end that increases maximum suspension stroke by a corresponding amount without adversely increasing the height of the suspension when it is in a substantially collapsed or fully collapsed position. In one preferred embodiment, the cam 54 has a height at its highest end that is at least 5 mm and no higher than 35 mm. In one preferred embodiment, the cam has a substantially linear contact surface that has an angle of inclination that can vary between 0° and 25°. The cam 54 preferably has a height at its lowest end that is substantially the same as the planar interior surface of the seat base 44 . Preferably, the cam surface 252 substantially continuously linearly tapers from the highest end to the lowest end where the cam surface 252 meets the substantially planar interior surface of the seat base 44 .

[0125] The cam 54 is made of a durable and resilient, and long-lasting material that preferably is of metallic construction. For example, in a currently preferred embodiment, the cam 54 is made or formed of metal. If desired, other materials, such as plastic, alloy steel, or the like, can be used.

[0126] In assembly, the suspension cartridge 48 is attached to either the seat platform 42 or the base 44 , depending upon the desired configuration sought to be obtained. Where the suspension cartridge 48 is used in conjunction with a cam 54 , the cam 54 is attached to the other one of the seat platform 42 or base 44 .

[0127] To attach the suspension cartridge 48 , a plurality of spaced apart rivets 114 ( FIG. 3 ) preferably are used to fix the cartridge housing end wall 60 to the platform 42 or the base 44 . While the cam 54 can be attached in a like manner, at least one fastener (not shown) preferably is used to fix the cam 54 to the other of the platform 42 or base 44 .

[0128] In assembling the suspension cartridge 48 , the suspension cartridge housing preferably functions as a frame or skeleton that carries or supports the rest of the components of the cartridge. In putting together the hanger assembly 74 , a pair of rivets 134 are used to fix the upper hanger yoke 75 to the lower hanger yoke 75 , with the barrel nut 132 captured between the yokes 75 . The hanger assembly 74 is then manipulated so as to be received in the clearance notch 208 of slot 66 in the cartridge housing so as to position the barrel nut 132 inside the cartridge housing, with the biasing element retaining arms extending outwardly on each side beyond the housing 56 ′.

[0129] The adjuster rod 128 is assembled to the weight adjust knob 124 , inserted through the height adjust knob 126 , and inserted through the threaded bore 184 in the cartridge housing end cap 182 . The threaded stem 148 of the height adjust knob 126 is threaded into the threaded bore 184 in the cartridge housing end cap 182 . This entire assembly is maneuvered toward the cartridge housing 56 ′ so as to position the end cap 182 against the outer axial edge of the housing 56 ′ such that it seats in end cap groove 196 and the adjuster rod 128 is threadably received by the barrel nut 132 . The adjuster rod 128 is threaded into and through the barrel nut 132 such that at least part of the rod 128 extends outwardly beyond the barrel nut 132 .

[0130] The suspension arm arrangement 50 is also put together as a subassembly. The roller 52 or 52 ′ is placed between a pair of bell crank arm plates 82 ′ and the axle shaft 118 is inserted through the bore 232 in one of the plates, through the hub 266 of the roller, and through the bore 232 in the other one of the plates. Retainers, such as a clip or the like, can be attached to each end of the axle shaft 118 to prevent the shaft from pulling free of either plate and the hub 266 .

[0131] The bell crank pivot shaft 86 is assembled to each bell crank arm plate 82 ′. In assembly, a bearing sleeve 94 , or the like, is received in each diametrically necked down portion 244 of the shaft 118 . Thereafter, each shaft end 244 and its corresponding bearing 94 are inserted into a corresponding bore 230 in each one of the bell crank arm plates 82 ′. Retainers, such as a clip or the like, can be attached to each end of the pivot shaft 86 to prevent the shaft from pulling free.

[0132] The biasing element retainer shaft 70 is assembled to each bell crank arm plate 82 ′. In assembly, the shaft 70 is inserted through a corresponding bore 228 in each one of the bell crank arm plates 82 ′. Thereafter, the shaft 70 is fixed to the plates 82 ′ by welding or the like. A bearing clip 156 is snapped into each shaft groove 160 .

[0133] The suspension arm subassembly is then assembled to the cartridge housing 56 ′. In assembly, the subassembly is manipulated so as to position the bell crank pivot shaft 86 , with its bearings 94 attached, and the biasing element retainer shaft 70 respectively in notch 88 ′ and in notch 68 . In the preferred embodiment shown in FIGS. 7 - 12 , no retainer clip preferably is needed to axially retain shaft 86 because each cartridge housing sidewall ear 90 advantageously also functions as a retainer, in conjunction with each bearing flange 95 , thereby reducing the number of suspension components needed.

[0134] With the biasing element hanger assembly 74 disposed in an aft most position, each biasing element preferably is attached at one end to the biasing element hanger assembly 74 and at its other end to the biasing element retainer shaft 70 . The damper is manipulated so as to position it inside the cartridge housing in between the sidewalls of the housing.

[0135] The damper is then attached at one end to the shaft 70 by a coupler 190 , preferably by wrapping a coupling strap 206 around the biasing element retainer shaft 70 . In one preferred embodiment, the coupler 190 is arranged to facilitate adjuster rod rotation. For example, if desired, the damper piston rod 100 can be constructed and arranged to rotate relative to the damper housing. If desired, the damper 96 can be coupled to the biasing element retainer shaft 70 in a manner that allows the damper 96 to rotate substantially in unison with the adjuster rod 128 and relative to the biasing element retainer shaft 70 . In one preferred embodiment, there is a second rod (not shown) that extends outwardly from the damper housing to which clip 206 attaches. Attachment preferably can be in a manner that facilitates relative rotation therebetween. If desired, another arrangement can be implemented to accommodate adjuster rod rotation and damper coupling to the biasing element retainer shaft 70 .

[0136] In one preferred method of assembly, the piston 100 of the damper 96 is maneuvered so as to move its end out of line relative to the adjuster rod 128 . The coupling tube 200 of the coupling assembly 188 is telescoped over the damper piston 100 such that there is clearance between the piston 100 and/or the tube 200 and the end of the adjuster rod 128 . Thereafter, the coupling tube 200 and damper piston 100 are brought in line with the adjuster rod 128 . The tube 200 is then slid over the free end of the adjuster rod 128 and rotated until its aft most bore lies in registry with a corresponding bore in the damper piston 100 . One end of the coupling wire 202 is manipulated so as to be received through both bores. Thereafter, the other end of the coupling wire 202 is brought into registry with the other bore in the coupling tube 200 , and the weight adjust rod 128 is rotated until a bore disposed in the shaft 128 adjacent its free end receives the coupling wire end. Further rotation of the weight adjustment shaft 128 simply causes a change in biasing element preload (e.g., change in tension or compression).

[0137] Referring additional to FIG. 13 , since damping force during suspension operation is linearly dependent on velocity, the velocity ratio is indicative of damping effectiveness. This chart of FIG. 13 shows that in a conventional prior art damper configuration, the effectiveness 300 of that damper arrangement is dramatically different at different suspension stroke positions. Near the top of suspension travel, a typical prior art plate-to-plate damper arrangement is more effective than at mid-stroke, and near the bottom of the travel there is nearly no system damping. These inconsistent damping characteristics are undesirable. As is further shown in FIG. 13 , the preferred damper arrangement depicted in FIGS. 7 - 9 provides for nearly constant damping behavior 302 which allows for more predictable, tunable and consistent vibration isolation throughout all suspension stroke positions. In fact, damping effectiveness increases at and near full suspension stroke as compared to the prior art, which provides virtually no system damping.

[0138] In operation, the suspension arm arrangement 50 extends outwardly such that the roller 52 bears against either the cam 54 or directly against the seat base 44 . As the suspension is loaded, force from the load is transferred along the bell crank arms 82 ′, causing the bell crank arms to pivot about the pivot shaft 86 . This pivoting action creates a moment arm about the pivot shaft 86 that causes the load to be transferred to the biasing elements 72 and the damper 96 . During suspension operation, the biasing elements 72 and the damper 96 work in concert to help absorb vibration, jolts, shocks, and other types of loading conditions that the suspension 40 may encounter.

[0139] To adjust the height of the seat relative to the base 44 , the height adjust knob 126 is rotated. As the knob 126 is rotated, it displaces the biasing elements 72 , the damper 96 , the spring hanger assembly 74 , and the biasing element retainer shaft 70 in unison in either a fore direction or an aft direction, depending on the direction of knob rotation. Within the limits dictated by the components, layout and arrangement of the suspension 40 , height adjustment preferably is infinitely variable.

[0140] To adjust the weight resistance of the suspension 40 , the weight adjust knob 124 is rotated. As the knob 124 is rotated, it causes relative movement between the biasing element hanger assembly 74 and the biasing element retainer shaft 70 , which changes the biasing element preload. Depending on the direction of rotation of the knob 124 , the suspension 40 can be made firmer or softer. Within the limits dictated by the components, layout and arrangement of the suspension 40 , weight adjustment preferably is infinitely variable.

Recapitulation

[0141] Due to space constraints between the top and bottom plates, and connected linkage, it is desirable to be able to install an element that contains both the energy adjustment, and vertical height adjustment encompassed in one module. The invention allows for assembly of a mechanical system that incorporates discrete vertical and weight adjustment mechanisms in a single freestanding element (vertical/weight energy cartridge). The freestanding element can be more easily assembled to the aforementioned seat suspension. This is a departure from that of a traditional suspension embodiment that would otherwise be more time and labor intensive during the assembly process.

[0142] The energy cartridge system of this invention is self-contained. All spring forces preferably are managed within the cartridge assembly. This allows the assembly of the energy cartridge to be independent of the suspension final assembly. The entire module preferably is attached to the top plate of a scissors style suspension, preferably using rivets, tabs, or screws. The invention does not require welding, which is a significant improvement over the prior art. The large roller bears on a suspension plate structure, such as the bottom plate structure shown, to drive the suspension vertically to oppose an external force applied to the suspension assembly and to suspend the operator mass.

[0143] A cylindrically shaped load bearing surface, positioned between a tension adjust knob and a front formed tab of the cartridge housing allows the springs, spring hanger, tension adjust shaft, and knob, to continuously align generally or substantially normal relative to the bell crank spring anchor center, throughout suspension travel. One end of an extension spring is attached to a spring hanger bracket that is connected to the tension adjust shaft with a threaded barrel shaped weight adjust nut. The barrel nut weight adjust nut allows the spring hanger to freely rotate or pivot about the vertical axis of the nut, thereby allowing the force applied by each extension spring to equalize. The spring hook attachment points, one at the spring hanger bracket and the opposite at the bell crank spring anchor, are positioned to align the body of the spring, and thus the force vector of the spring, with the longitudinal axis of the tension adjust shaft. When combined, the spring hanger and weight adjust nut assembly, and the co-axial position of the spring mount location in the spring hanger, provides essentially purely axial loads on the tension adjust threads. This optimizes the thread friction condition, and reduces torque required to increase or decrease the extension spring pre-load to change the weight setting of the suspension.

[0144] The bell crank portion of the system preferably is assembled without requiring any retain