CA1190251A - Composite multileaf, multistage leaf spring - Google Patents
Composite multileaf, multistage leaf springInfo
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- CA1190251A CA1190251A CA000377835A CA377835A CA1190251A CA 1190251 A CA1190251 A CA 1190251A CA 000377835 A CA000377835 A CA 000377835A CA 377835 A CA377835 A CA 377835A CA 1190251 A CA1190251 A CA 1190251A
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Abstract
ABSTRACT OF THE DISCLOSURE
A light weight leaf suitable for use in a multirate, multileaf spring is described. The leaf comprises a pultruded beam with about 40 to 75% by volume filamentary solids and a remainder fraction of continuous organic solid which binds together the filamentary solids. At least 80 wt.% of the filamentary solids comprises a multitude of discrete, tensilely stressed, filamentary solids which are densely packed substan-tially uniformly throughout the organic solid. These fila-mentary solids coextend the beam longitudinally in a plurality of planes that accept tensile or compressive stress, respec-tively, upon a flexure of the spring that bends the beam.
A light weight leaf suitable for use in a multirate, multileaf spring is described. The leaf comprises a pultruded beam with about 40 to 75% by volume filamentary solids and a remainder fraction of continuous organic solid which binds together the filamentary solids. At least 80 wt.% of the filamentary solids comprises a multitude of discrete, tensilely stressed, filamentary solids which are densely packed substan-tially uniformly throughout the organic solid. These fila-mentary solids coextend the beam longitudinally in a plurality of planes that accept tensile or compressive stress, respec-tively, upon a flexure of the spring that bends the beam.
Description
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CO~POSITE MULTILEAF, MULTISTAGE~ LEAF SPRING
This invention relates to vehicular suspension. More particularly, this invention relates -to a multileaf vehicular spring which has a light weight leaf. The leaf comprises about40 to 75%by volume filamen-tary solids of a first modulus and a remainder comprising continuous organic solid of a second, lower modulus.
Multileaf vehicular springs are known. See, for e~ample, U.S. Patent 2,052,062; 3,292,918 and 3,493,222.
Moreover, sprinys comprising leaves which contain filamentary solids in an organic solid are also known. See, for example U.S. Patents 2,600,843; 2,829,881 and 3,142,598.
The spring of this invention differ from those in such patents in that it is a multileaf, multirate spring that has a discrete, pultruded, secondary leaf having filamentary solids densely packed in certain fashion throughout a continuous organic solid.
; This invention relates to a vehicle leaf spring.
The spring has a light weight leaf. The leaf comprises a pultruded beam with about40 to 75%(preferably about 50 to 60% by volume filamentary solids and a remainder fraction (preferably about60 to 29% more preferably about 50 to 40%by volume) oE continuous organic solid. The organic solid binds together the filamentary solids.
At least about 80% (more preferably, at least about 90%) by weight of the filamentary solids comprises a multitude of discrete, tensilely stressed, filamentary solids, densely packed substantially uniformly throughout the organic solid. These discrete, tensilely stressed and densely packed, filamentary solids coextend the beam longitudinally in a plurality of planes that accept tensile or compressive stress, respec-tively, upon a flexure of the spring that bends the beam. Up to about 10% by weight of the filamentary solids comprises randomly oriented filamentary solids in a mat on a surface of the beam that receives longitudinal compressive stress.
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In preferred embodiments, the beam has between about 50 to 60% by volume glass fiber and more preferably more glass than organic solid by volume. Up -to about iO% by weight of the filamentary solids comprise woven filamentary solids that have fibers oriented across one another substantially in a plane of the aforementioned planes. In certain embodiments, the beam has a configuration that is substantially straight along a longitudinal axis without the aforementioned flexure. The beam has a cross-section that is preferably substantially rectilinear.
In an especially preferred embodiment, thisinvention relates to a multirate, multileaf vehicular spring. In such spring, a first leaf (normally a set of leaves comprising a first leaf) acts independently of a second leaf under a first load; but it acts together with the second leaf under a second load which is greater than the first load. The first leaf has ends adaptable to attach the spring to a vehicle at first and second vehicle locations. The second leaf has a center section bindable with a center section of the first leaf to the vehicle at a third vehicle location. The third vehicle location is between the first and second vehicle locations.
The improvement of the invention with respect to such a multirate spring comprises a second leaf that is a light weight leaf. The light weight leaf comprises a beam, preferably straight, that has about 40 to 75%
(preferably about 50 to 60%~ by volume filamentary solids of a fir~t modulus. A remainder fraction (preferably about 60 to 25%, more preferably about 50 to 40% by volume) comprises continuous organic solid of a second, lower modulus. The organic solid (e.g., vinylester or polyester or epoxy thermoset resin) binds together the filamentary solids. At least about 80% (preferably at least about 90~) by weight of the filamentary solids comprise a multi-tude of ,, . ~
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discrete, tensilely stressed fllamentary solids, densely packed subs-tantially uniformly throughout the organic solid. These discrete, densely packed and tensilely stressed, filamentary solids coextend the beam longitudinally in a plurality of planes that accept tensile or compressive stress, respectively, upon a flexure of the spring that bends the beam. The beam in these especially preferred embodiments is preferably substantially straight under the aforementioned first load. The beam preferably has a configuration that has a substantially rectilinear cross section. The beam also has a preferred glass content as well as random and woven filamentary solids as noted hereinabove.
The invention is described further, by way of illustration, with reference to the accompanying drawings, in which:
Figure 1 illustrates schematically operation multirate spring 150 in accordance with this invention.
Configurations I, II and III denote spring conditions, somewhat exaggerated for purposes of illustration, under increasingly larger loads;
Figure 2 illustrates graphically spring rates for multirate spring 250 of Figure 3, the ordinate being load in newtons and the absissa being spring height in millimeters;
Figure 3 illustrates multirate spring 250 of this invention, main leaf 157 appearing in flat main leaf condition;
Figure 4 illustrates the spring of Figure 3 looking in from II - II of Figure 3;
Figure 5 illustrates the spring of Figure 3 looking in from III - III of Figure 3;
Figure 6 shows spring seat 400 upon which a spring such as in Figure 3 may mount, the curvature shown as 402 accepting an axle member;
Figure 7 shows another view of spring seat 400 of Figure 6, this view looking up into the seat from a position of the axle, with the U-bolts having sections 410 and 412, respectively, that are part of a U-bolt assembly;
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Figure 8 is another view of spring seat 400 of Figure 6; and Figure 9 is a cross-section of beam 101 of Figure 4 that illustrates composition with respect to continuous 5 and discrete filamentary solids.
This invention re;ates ~o leaf springs comprising a light weight leaf. In p-eferred embodiments, the spring is a multileaf, multirate spring comprising a second stage leaf that is a pultruded beam. The beam in these embodi~ents 10 preferably has an unloaded configuration that is substantially straight.
Figure 1 of the drawings schematically illustrates operation of multileaf, multirate composite spring 150 of this invention~ Spring 150 has main leaf 156 and other 15 leaves 152 and 154. The composition of leaves 152, 154 and 156 is steel. Spring 150 additionally has leaf 100.
Leaf 100 comprises glass fibers in a thermoset matrix.
Configuration I of Figure 1 shows multirate spring 150 under a first load. Spring 150 conforms to configuration 20 I, when, for example, a vehicle carrying it is unloaded, e.g., "curb position".
Configuration III of Figure 1 shows multirate spring 150 under a second load, greater than the first load. Spring 1~0 conforms to Configuration III, when, 25 for example, a vehicle carrying has a capacity load, i.e., "normal load".
Configuration II of Figure 1 shows multirate spring 150 under a load intermediate between the first and second loads. In Configuration II, spring 150 is 30 in transition between first and second spring rates. The first spring rate has contributions from leaves 152, 154 and 156. The second spring rate has an additional con-tribution from leaf 100.
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Configuration II of Figure 1 shows main leaf 156 without camber. This position is commonly referred to as "flat main leaf". Flat main leaf may occur before or after transition between first and second spring rates.
Figure 2 approximates graphically a load (y axis in newtons) -- deflection (x axis, in millimeters) curve for multirate spring 250 oE Figure 3. The deflection measuremerlt corresponds to overall spring height~ The spring is unclamped and mounted on rollers during measurements.
The slope of line 200 corresponds to a spring rate of multirate spring 250 when it is in a configuration lLke I of Figure 1. The slope of line 202 corresponds to a spring rate of spring 250 when it is in a configuration like III of Figure 1. The intersection of lines 220 and 202 represents a transition between the spring rates.
~ emarcation 202 approximates flat main leaf c~nfiguration for multirate spring 250. Flat main leaf of spring 250 occurs before transition because spacer 180 (Figure 3) delays engagement of leaf 101 with the other leaves.
Figure 3 shows with greater particularity an embodiment of this invention. Multirate spring 250 has a set of leaves 153, 155 and 157; leaf 157 is the main leaf. Leaves 153, 155 and 157 comprise steel; they give spring 250 a first spring rate. Spring 250 has additional leaf 101. Leaf 101 comprises glass fibers in a thermoset matrix; it gives spring 250, with leaves 153, 155 and 157, a second spring rate.
Main leaf 157 of multirate spring 250 has "eyes"
140 and 160. Eyes 140 and 160 comprise integral curvatures 162 and 142 of main leaf 157. Eyes 140 and 160 contain press fitted bushing material 144 and 164, respectively. Within press fitted bushing material are metal sleeves 146 and 166, respectively. Spring 250 mounts to a vehicle through sleeves 146 and 166 at firs-t and second vehicle locations, i.e. (a) -the chassis or body on either side of the axle or (b) the axle at 5~
spaced locations. Sleeves 146 and 177 mount, respectively fixedly and translatably at spaced vehicle locations. Thus, as leaves of multirate spring 250 flux, multirate spring 250 has an end that translates upwardly or downwardly at the translatable mount (e.g., shackle).
Clip 170 of Figure 3 holds leaves 153, 155 and 157 together; i-t prevents excessive splaying of leaves 153, 155 and 157. An additional clip (not shown) may also 10hold leaves 153, 155 and 157 at a corresponding, opposite end portion of multirate spring 250. Spring 50 of Figure 3, mounts fore and aft of the vehicle axle. Clip 170, which is forward of the axle, thus prevents entry of gravel or other particulate between 15leaves 153, 15S and 157, particularly during acceleration of the vehicle.
Fastening means 190 of Figure 3 extends through leaves 153, 155, 157 and 101; it permits alignment of spring 250 in spring seat 400 of Figures 6, 7 and 8.
20Fastening means 190 also extends through spacer 180 as shown more particularly in Figure 4. Spacer 180 delays engagement of leaf 101 beyond "flat main leaf" condition of main leaf 157. Spacer 180 comprises aluminum but may be any other such formable material.
25Figure 4 is a section taken of multirate spring 250 looking in at II-II of Figure 3. Fastening means 190, as shown, comprises threaded bolt 19 having cap 196 and nut 194. Bolt 192 fits snugly in orifice 198 of leaves 153, 155 and 157 and orifice 102 of leaf 101. Cap 196 30fits into orifice 408 of spring seat 400. Spacer 180 of Figure 4 has integral creep resistors 182 that wrap leaf 101. Leaf 101 has curvatures 104 that fit snugly into the intersection of spacer portion 184 and creep resistance portions 182 of spacer 180. Creep resistance 35portions 182 of spacer 180 resist creep of leaf 101 during operation of multirate spring 250.
Figure 5 shows a cross section of clip 170 lookiny in at III-III. Rivet 172 fits tightly into orifices 172 - and 174 of clip 176 and leaf 153, respectively. The 5~
head of rive-t 172 maintains enyagement of cllp 176 with leaf 153.
Figures 6, 7 and 8 show side views and a bottom view (looking up from the axle) of spring seat 400.
Seat 400 comprises a top, flat portion 406 upon which multirate spriny 250 rides. Flat portion 406 has a width equal or slightly greater than the width of leaf 101; it has a length about two times its width. Seat 400 has orifice 408. Bolt head 196 fits into orifice 408.
Spring seat 400 has curvature 402. Curvature 402 mirrors axle housing (not shown) curvature. Nubs 420 interrupt curvature 402. Durinq assembly of multirate spring 250 to a vehicle, nubs 420 provide metal that welds seat 400 to the axle housing. Nubs 420, accordingly, disappear during welding operation.
Spring seat has an external curvature shown by 404 in Figures 6 and 7. Curvature 404 slopes away from flat portion 406. Thus, flat portion 406 exists as a plateau upon which multirate spring 250 rides. The plateau provides smooth engagement between beam 101 and seat 400.
Figure 8 is a view of spring seat 400 looking up from an axle position. Figure 8 shows sections 410 and 412 of members of U-bolt assemblies. The U-bolt assemblies are conventional; they wrap around the axle housing. They engage a single plate above leaf 157 of Figure 3.
Figure 9 illustrates a section of leaf 101. The section is substantially rectilinear with corners having a small radius. Leaf 101 comprises filamentar~7 solids in a continuous organic solid.
Figure 9 illustrates material composition at a cross-section of leaf 101. Sections 500, 502 and 510 of leaf 101 show relative position and character of filamentary solids in thermoset matrix 504. Sections 500, 502 and 510 extend the length of leaf 101.
Leaf 101 has about 54~ by volume filamentary solids which comprise glass fibers; the remainder of leaf 101 5~
is a continuous organic solid (thermoset polyester esin) that binds the filamentary solids toge-ther.
Leaf 101 of Figure 9 has been made by a pultrusion process~ In the pultrusion process, pullers draw resin coated filaments through a heated die. The resin hardens in the die. Examples of pultrusion processes appear in U.S. Paten-ts 4,1S4,634; 3,853,656; 3,793,108;
3,68A,622; 3,674,601; 3,530,212; and 2,741,294.
Leaf 101 of Figure 9 has three orientations of filamentary solids. Greater than about 95% by weight of the filamentary solids comprise a multitude of discrete, tensilely stressed, filamentary solids densely packed substantially uniformly throughout thermoset polyester 504. These densely packed, tensilely stressed, filamentary solids coextend leaf 101 in a plurality of planes. The planes receive tensile or compressive stress upon flexure of multirate spring 250 (Figure 3) that bends leaf 101. Ends of a portion of such tensilely stressed solids appear as 510 in Figure 9.
(Ends 510 are slightly enlarged relative to the remainder of leaf 101. Also, ends of other of these filamentary solids, substantially uniformly dispersed throughout leaf 101, have been omitted from Figure 9 for clarity.) Less than about 2% by weight of the filamen-tary solids of leaf 101 comprises randomly oriented filamentary solids. Portion 502 in Figure 9 shows position of these randomly oriented filamentary solids in leaf 101. The randomly oriented solids form a mat (e.g., glass fiber mat) on a surface of leaf 101. The mat side of leaf 101 rests on spring seat 40C in multirate spring 250 of Figure 3. (Portion 502 exaggerates for purposes of illustration the relative volume taken by the randomly oriented filamentary solids. The mat of leaf 101 is actually only a few glass fibers thick.~
Less than about 2% by weight of the filamentary solids in leaf 101 comprise a weave of filamentary solids. The weave is held tightly within the above 5~
noted multi-tude of filamentary solids. Portions 500 of Figure 9 illustrate positions of the weave ln leaf 101.
The weave has filamentary solids positioned across one another. The weave contains fibers -that are transverse to -the long dimension of leaf 101. These transverse fibers reduce creep of leaf 101 in multirate spring 250.
(Portions 500 exaggerate Eor purposes of illustration the relative volume taken by the weaves. Each weave in leaf 101 is compressed such that it has a volume that is about 1 or 10 fibers thick in a cross section cf leaf 10 101. ) The weave of filamentary solids in leaf 101, as mentioned, reduces creep of leaf 101 in multirate spring 250. In an alternative embodiment of multirate spring 250, leaf 101 comprises such weave but omits spacer creep resistors 182 shown in Figuxe 4. In this embodiment leaf 101 and leaves 153, 155 and 157 have equal widths.
In still other embodiments, leaf 101 is as above described with respect to continuous and filamentary solids, but, when unloaded, has camber. In a multirate spring embodiment, such a cambered leaf may engage leaves 153, 155 and 157 before or after flat main leaf position of leaf 157 in Figure 3, depending, for example, on whether leaf 101 has a positive or negative curvature with respect to leaf 157. In still other multirate spring embodiments, such a cambered leaf is a leaf of the first set of leaves as well as the second stage leaf.
CO~POSITE MULTILEAF, MULTISTAGE~ LEAF SPRING
This invention relates to vehicular suspension. More particularly, this invention relates -to a multileaf vehicular spring which has a light weight leaf. The leaf comprises about40 to 75%by volume filamen-tary solids of a first modulus and a remainder comprising continuous organic solid of a second, lower modulus.
Multileaf vehicular springs are known. See, for e~ample, U.S. Patent 2,052,062; 3,292,918 and 3,493,222.
Moreover, sprinys comprising leaves which contain filamentary solids in an organic solid are also known. See, for example U.S. Patents 2,600,843; 2,829,881 and 3,142,598.
The spring of this invention differ from those in such patents in that it is a multileaf, multirate spring that has a discrete, pultruded, secondary leaf having filamentary solids densely packed in certain fashion throughout a continuous organic solid.
; This invention relates to a vehicle leaf spring.
The spring has a light weight leaf. The leaf comprises a pultruded beam with about40 to 75%(preferably about 50 to 60% by volume filamentary solids and a remainder fraction (preferably about60 to 29% more preferably about 50 to 40%by volume) oE continuous organic solid. The organic solid binds together the filamentary solids.
At least about 80% (more preferably, at least about 90%) by weight of the filamentary solids comprises a multitude of discrete, tensilely stressed, filamentary solids, densely packed substantially uniformly throughout the organic solid. These discrete, tensilely stressed and densely packed, filamentary solids coextend the beam longitudinally in a plurality of planes that accept tensile or compressive stress, respec-tively, upon a flexure of the spring that bends the beam. Up to about 10% by weight of the filamentary solids comprises randomly oriented filamentary solids in a mat on a surface of the beam that receives longitudinal compressive stress.
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In preferred embodiments, the beam has between about 50 to 60% by volume glass fiber and more preferably more glass than organic solid by volume. Up -to about iO% by weight of the filamentary solids comprise woven filamentary solids that have fibers oriented across one another substantially in a plane of the aforementioned planes. In certain embodiments, the beam has a configuration that is substantially straight along a longitudinal axis without the aforementioned flexure. The beam has a cross-section that is preferably substantially rectilinear.
In an especially preferred embodiment, thisinvention relates to a multirate, multileaf vehicular spring. In such spring, a first leaf (normally a set of leaves comprising a first leaf) acts independently of a second leaf under a first load; but it acts together with the second leaf under a second load which is greater than the first load. The first leaf has ends adaptable to attach the spring to a vehicle at first and second vehicle locations. The second leaf has a center section bindable with a center section of the first leaf to the vehicle at a third vehicle location. The third vehicle location is between the first and second vehicle locations.
The improvement of the invention with respect to such a multirate spring comprises a second leaf that is a light weight leaf. The light weight leaf comprises a beam, preferably straight, that has about 40 to 75%
(preferably about 50 to 60%~ by volume filamentary solids of a fir~t modulus. A remainder fraction (preferably about 60 to 25%, more preferably about 50 to 40% by volume) comprises continuous organic solid of a second, lower modulus. The organic solid (e.g., vinylester or polyester or epoxy thermoset resin) binds together the filamentary solids. At least about 80% (preferably at least about 90~) by weight of the filamentary solids comprise a multi-tude of ,, . ~
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discrete, tensilely stressed fllamentary solids, densely packed subs-tantially uniformly throughout the organic solid. These discrete, densely packed and tensilely stressed, filamentary solids coextend the beam longitudinally in a plurality of planes that accept tensile or compressive stress, respectively, upon a flexure of the spring that bends the beam. The beam in these especially preferred embodiments is preferably substantially straight under the aforementioned first load. The beam preferably has a configuration that has a substantially rectilinear cross section. The beam also has a preferred glass content as well as random and woven filamentary solids as noted hereinabove.
The invention is described further, by way of illustration, with reference to the accompanying drawings, in which:
Figure 1 illustrates schematically operation multirate spring 150 in accordance with this invention.
Configurations I, II and III denote spring conditions, somewhat exaggerated for purposes of illustration, under increasingly larger loads;
Figure 2 illustrates graphically spring rates for multirate spring 250 of Figure 3, the ordinate being load in newtons and the absissa being spring height in millimeters;
Figure 3 illustrates multirate spring 250 of this invention, main leaf 157 appearing in flat main leaf condition;
Figure 4 illustrates the spring of Figure 3 looking in from II - II of Figure 3;
Figure 5 illustrates the spring of Figure 3 looking in from III - III of Figure 3;
Figure 6 shows spring seat 400 upon which a spring such as in Figure 3 may mount, the curvature shown as 402 accepting an axle member;
Figure 7 shows another view of spring seat 400 of Figure 6, this view looking up into the seat from a position of the axle, with the U-bolts having sections 410 and 412, respectively, that are part of a U-bolt assembly;
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Figure 8 is another view of spring seat 400 of Figure 6; and Figure 9 is a cross-section of beam 101 of Figure 4 that illustrates composition with respect to continuous 5 and discrete filamentary solids.
This invention re;ates ~o leaf springs comprising a light weight leaf. In p-eferred embodiments, the spring is a multileaf, multirate spring comprising a second stage leaf that is a pultruded beam. The beam in these embodi~ents 10 preferably has an unloaded configuration that is substantially straight.
Figure 1 of the drawings schematically illustrates operation of multileaf, multirate composite spring 150 of this invention~ Spring 150 has main leaf 156 and other 15 leaves 152 and 154. The composition of leaves 152, 154 and 156 is steel. Spring 150 additionally has leaf 100.
Leaf 100 comprises glass fibers in a thermoset matrix.
Configuration I of Figure 1 shows multirate spring 150 under a first load. Spring 150 conforms to configuration 20 I, when, for example, a vehicle carrying it is unloaded, e.g., "curb position".
Configuration III of Figure 1 shows multirate spring 150 under a second load, greater than the first load. Spring 1~0 conforms to Configuration III, when, 25 for example, a vehicle carrying has a capacity load, i.e., "normal load".
Configuration II of Figure 1 shows multirate spring 150 under a load intermediate between the first and second loads. In Configuration II, spring 150 is 30 in transition between first and second spring rates. The first spring rate has contributions from leaves 152, 154 and 156. The second spring rate has an additional con-tribution from leaf 100.
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Configuration II of Figure 1 shows main leaf 156 without camber. This position is commonly referred to as "flat main leaf". Flat main leaf may occur before or after transition between first and second spring rates.
Figure 2 approximates graphically a load (y axis in newtons) -- deflection (x axis, in millimeters) curve for multirate spring 250 oE Figure 3. The deflection measuremerlt corresponds to overall spring height~ The spring is unclamped and mounted on rollers during measurements.
The slope of line 200 corresponds to a spring rate of multirate spring 250 when it is in a configuration lLke I of Figure 1. The slope of line 202 corresponds to a spring rate of spring 250 when it is in a configuration like III of Figure 1. The intersection of lines 220 and 202 represents a transition between the spring rates.
~ emarcation 202 approximates flat main leaf c~nfiguration for multirate spring 250. Flat main leaf of spring 250 occurs before transition because spacer 180 (Figure 3) delays engagement of leaf 101 with the other leaves.
Figure 3 shows with greater particularity an embodiment of this invention. Multirate spring 250 has a set of leaves 153, 155 and 157; leaf 157 is the main leaf. Leaves 153, 155 and 157 comprise steel; they give spring 250 a first spring rate. Spring 250 has additional leaf 101. Leaf 101 comprises glass fibers in a thermoset matrix; it gives spring 250, with leaves 153, 155 and 157, a second spring rate.
Main leaf 157 of multirate spring 250 has "eyes"
140 and 160. Eyes 140 and 160 comprise integral curvatures 162 and 142 of main leaf 157. Eyes 140 and 160 contain press fitted bushing material 144 and 164, respectively. Within press fitted bushing material are metal sleeves 146 and 166, respectively. Spring 250 mounts to a vehicle through sleeves 146 and 166 at firs-t and second vehicle locations, i.e. (a) -the chassis or body on either side of the axle or (b) the axle at 5~
spaced locations. Sleeves 146 and 177 mount, respectively fixedly and translatably at spaced vehicle locations. Thus, as leaves of multirate spring 250 flux, multirate spring 250 has an end that translates upwardly or downwardly at the translatable mount (e.g., shackle).
Clip 170 of Figure 3 holds leaves 153, 155 and 157 together; i-t prevents excessive splaying of leaves 153, 155 and 157. An additional clip (not shown) may also 10hold leaves 153, 155 and 157 at a corresponding, opposite end portion of multirate spring 250. Spring 50 of Figure 3, mounts fore and aft of the vehicle axle. Clip 170, which is forward of the axle, thus prevents entry of gravel or other particulate between 15leaves 153, 15S and 157, particularly during acceleration of the vehicle.
Fastening means 190 of Figure 3 extends through leaves 153, 155, 157 and 101; it permits alignment of spring 250 in spring seat 400 of Figures 6, 7 and 8.
20Fastening means 190 also extends through spacer 180 as shown more particularly in Figure 4. Spacer 180 delays engagement of leaf 101 beyond "flat main leaf" condition of main leaf 157. Spacer 180 comprises aluminum but may be any other such formable material.
25Figure 4 is a section taken of multirate spring 250 looking in at II-II of Figure 3. Fastening means 190, as shown, comprises threaded bolt 19 having cap 196 and nut 194. Bolt 192 fits snugly in orifice 198 of leaves 153, 155 and 157 and orifice 102 of leaf 101. Cap 196 30fits into orifice 408 of spring seat 400. Spacer 180 of Figure 4 has integral creep resistors 182 that wrap leaf 101. Leaf 101 has curvatures 104 that fit snugly into the intersection of spacer portion 184 and creep resistance portions 182 of spacer 180. Creep resistance 35portions 182 of spacer 180 resist creep of leaf 101 during operation of multirate spring 250.
Figure 5 shows a cross section of clip 170 lookiny in at III-III. Rivet 172 fits tightly into orifices 172 - and 174 of clip 176 and leaf 153, respectively. The 5~
head of rive-t 172 maintains enyagement of cllp 176 with leaf 153.
Figures 6, 7 and 8 show side views and a bottom view (looking up from the axle) of spring seat 400.
Seat 400 comprises a top, flat portion 406 upon which multirate spriny 250 rides. Flat portion 406 has a width equal or slightly greater than the width of leaf 101; it has a length about two times its width. Seat 400 has orifice 408. Bolt head 196 fits into orifice 408.
Spring seat 400 has curvature 402. Curvature 402 mirrors axle housing (not shown) curvature. Nubs 420 interrupt curvature 402. Durinq assembly of multirate spring 250 to a vehicle, nubs 420 provide metal that welds seat 400 to the axle housing. Nubs 420, accordingly, disappear during welding operation.
Spring seat has an external curvature shown by 404 in Figures 6 and 7. Curvature 404 slopes away from flat portion 406. Thus, flat portion 406 exists as a plateau upon which multirate spring 250 rides. The plateau provides smooth engagement between beam 101 and seat 400.
Figure 8 is a view of spring seat 400 looking up from an axle position. Figure 8 shows sections 410 and 412 of members of U-bolt assemblies. The U-bolt assemblies are conventional; they wrap around the axle housing. They engage a single plate above leaf 157 of Figure 3.
Figure 9 illustrates a section of leaf 101. The section is substantially rectilinear with corners having a small radius. Leaf 101 comprises filamentar~7 solids in a continuous organic solid.
Figure 9 illustrates material composition at a cross-section of leaf 101. Sections 500, 502 and 510 of leaf 101 show relative position and character of filamentary solids in thermoset matrix 504. Sections 500, 502 and 510 extend the length of leaf 101.
Leaf 101 has about 54~ by volume filamentary solids which comprise glass fibers; the remainder of leaf 101 5~
is a continuous organic solid (thermoset polyester esin) that binds the filamentary solids toge-ther.
Leaf 101 of Figure 9 has been made by a pultrusion process~ In the pultrusion process, pullers draw resin coated filaments through a heated die. The resin hardens in the die. Examples of pultrusion processes appear in U.S. Paten-ts 4,1S4,634; 3,853,656; 3,793,108;
3,68A,622; 3,674,601; 3,530,212; and 2,741,294.
Leaf 101 of Figure 9 has three orientations of filamentary solids. Greater than about 95% by weight of the filamentary solids comprise a multitude of discrete, tensilely stressed, filamentary solids densely packed substantially uniformly throughout thermoset polyester 504. These densely packed, tensilely stressed, filamentary solids coextend leaf 101 in a plurality of planes. The planes receive tensile or compressive stress upon flexure of multirate spring 250 (Figure 3) that bends leaf 101. Ends of a portion of such tensilely stressed solids appear as 510 in Figure 9.
(Ends 510 are slightly enlarged relative to the remainder of leaf 101. Also, ends of other of these filamentary solids, substantially uniformly dispersed throughout leaf 101, have been omitted from Figure 9 for clarity.) Less than about 2% by weight of the filamen-tary solids of leaf 101 comprises randomly oriented filamentary solids. Portion 502 in Figure 9 shows position of these randomly oriented filamentary solids in leaf 101. The randomly oriented solids form a mat (e.g., glass fiber mat) on a surface of leaf 101. The mat side of leaf 101 rests on spring seat 40C in multirate spring 250 of Figure 3. (Portion 502 exaggerates for purposes of illustration the relative volume taken by the randomly oriented filamentary solids. The mat of leaf 101 is actually only a few glass fibers thick.~
Less than about 2% by weight of the filamentary solids in leaf 101 comprise a weave of filamentary solids. The weave is held tightly within the above 5~
noted multi-tude of filamentary solids. Portions 500 of Figure 9 illustrate positions of the weave ln leaf 101.
The weave has filamentary solids positioned across one another. The weave contains fibers -that are transverse to -the long dimension of leaf 101. These transverse fibers reduce creep of leaf 101 in multirate spring 250.
(Portions 500 exaggerate Eor purposes of illustration the relative volume taken by the weaves. Each weave in leaf 101 is compressed such that it has a volume that is about 1 or 10 fibers thick in a cross section cf leaf 10 101. ) The weave of filamentary solids in leaf 101, as mentioned, reduces creep of leaf 101 in multirate spring 250. In an alternative embodiment of multirate spring 250, leaf 101 comprises such weave but omits spacer creep resistors 182 shown in Figuxe 4. In this embodiment leaf 101 and leaves 153, 155 and 157 have equal widths.
In still other embodiments, leaf 101 is as above described with respect to continuous and filamentary solids, but, when unloaded, has camber. In a multirate spring embodiment, such a cambered leaf may engage leaves 153, 155 and 157 before or after flat main leaf position of leaf 157 in Figure 3, depending, for example, on whether leaf 101 has a positive or negative curvature with respect to leaf 157. In still other multirate spring embodiments, such a cambered leaf is a leaf of the first set of leaves as well as the second stage leaf.
Claims (17)
1. In a multirate, multileaf vehicular spring comprising a first leaf that acts independently of a second leaf under a first load but together with said second leaf under a second load, greater than said first load, said first leaf having ends adaptable to attach said spring to a vehicle at first and second vehicle locations, respectively, said second leaf having a center section bindable with a center section of said first leaf to said vehicle at a third vehicle location between said first and second vehicle locations, the improvement wherein said second leaf comprises a pultruded beam that has about 40 to 75% by volume filamentary solids of a first modulus and a remainder fraction comprising continuous organic solid of a second, lower modulus that binds together said filamentary solids, at least about 80% by weight of said filamentary solids being a multitude of discrete, tensilely stressed filamentary solids, densely packed substantially uniformly throughout said organic solid and coextending said beam longitudinally in a plurality of planes that accept tensile or compressive stress, respectively, upon a flexure of said spring that bends said beam, a surface of said pultruded beam having up to about 10% by weight of randomly-oriented filamentary solids in a mat on a surface of said beam that receives longitudinal compressive stress.
2. A spring in accordance with Claim 1, wherein said beam has between about 50 to 60% by volume of glass.
3. A spring in accordance with Claim 2, wherein said beam is made by pultrusion.
4. A spring in accordance with Claim 3, wherein said organic solid comprises polyester or vinyl thermoset resin.
5. A spring in accordance with Claim 1, 2 or 3, wherein said beam comprises up to about 10% by weight of woven filamentary solids that has fibers oriented substantially across one another substantially in a plane of said planes.
6. A spring in accordance with Claim 1, 2 or 3, wherein said beam comprises up to about 10% by weight of woven filamentary solids that has fibers oriented substantially across one another substantially in a plane of said planes, and said beam has a configuration that is substantially straight without said flexure.
7. A spring in accordance with Claim 1, 2 or 3, wherein said beam comprises up to about 10% by weight of woven filamentary solids that has fibers oriented substantially across one another substantially in a plane of said planes, said beam has a configuration that is substantially straight without said flexure, and said configuration has a substantially rectilinear cross section.
8. A spring in accordance with Claim 4, wherein said beam comprises up to about 10% by weight of woven filamentary solids that has fibers oriented substantially across one another substantially in a plane of said planes.
9. A spring in accordance with Claim 4, wherein said beam comprises up to about 10% by weight of woven filamentary solids that has fibers oriented substantially across one another substantially in a plane of said planes, and said beam has a configuration that is substantially straight without said flexure.
10. A spring in accordance with Claim 4, wherein said beam comprises up to about 10% by weight of woven filamentary solids that has fibers oriented substantially across one another substantially in a plane of said planes, said beam has a configuration that is substantially straight without said flexure, and said configuration has a sub-stantially rectilinear cross section.
11. In a multirate, multileaf spring comprising a set of leaves that acts independently of a second leaf under a first load but together with said second leaf under a second load, greater than said first load, said ?
set of leaves comprising a first leaf that has ends adaptable to attach said spring to a vehicle at first and second vehicle locations, respectively, said second leaf having a center section bindable with a center section of said first leaf to a third vehicle location between said first and second vehicle locations, the improvement which comprises wherein said second leaf comprises under said first load a substantial straight pultruded beam that has about 50 to 60% by volume filamentary solids of a first modulus and a remainder fraction comprising continuous organic solids of a second, lower modulus that binds together said fila-mentary solids, at least about 80% by weight of said fila-mentary solids being a multitude of discrete, tensilely stressed filamentary solids, densely packed substantially uniformly throughout said organic solids and coextending said beam longitudinally in a plurality of planes that accept tensile or compressive stress, respectively, upon a flexure of said spring that bends said beam, a surface of said beam having up to about 10% by weight randomly oriented filamentary solids on a surface of said beam that receives longitudinal compressive stress.
set of leaves comprising a first leaf that has ends adaptable to attach said spring to a vehicle at first and second vehicle locations, respectively, said second leaf having a center section bindable with a center section of said first leaf to a third vehicle location between said first and second vehicle locations, the improvement which comprises wherein said second leaf comprises under said first load a substantial straight pultruded beam that has about 50 to 60% by volume filamentary solids of a first modulus and a remainder fraction comprising continuous organic solids of a second, lower modulus that binds together said fila-mentary solids, at least about 80% by weight of said fila-mentary solids being a multitude of discrete, tensilely stressed filamentary solids, densely packed substantially uniformly throughout said organic solids and coextending said beam longitudinally in a plurality of planes that accept tensile or compressive stress, respectively, upon a flexure of said spring that bends said beam, a surface of said beam having up to about 10% by weight randomly oriented filamentary solids on a surface of said beam that receives longitudinal compressive stress.
12. A spring in accordance with Claim 11, wherein said beam comprises up to about 10% by weight woven fila-mentary solids oriented substantially across one another substantially in a plane of said plurality of planes.
13. A spring in accordance with Claim 11 or 12, wherein said filamentary solids comprises glass.
14. A spring in accordance with Claim 11 or 12, wherein said filamentary solids comprises glass, and said beam is made by a pultrusion process.
15. A spring in accordance with Claim 11 or 12, wherein said filamentary solids comprises glass, said beam is made by a pultrusion process and said beam has a cross section that is substantially rectilinear.
16. A spring in accordance with Claim 11 or 12, wherein said filamentary solids comprises glass, said beam is made by a pultrusion process, said beam has a cross section that is substantially rectilinear and said organic solid comprises a vinyl or polyester, thermoset resin.
17. A spring in accordance with Claim 1, 11 or 12, wherein said organic solid comprises thermoset resin.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US15054880A | 1980-05-16 | 1980-05-16 | |
| US150,548 | 1980-05-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1190251A true CA1190251A (en) | 1985-07-09 |
Family
ID=22535041
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000377835A Expired CA1190251A (en) | 1980-05-16 | 1981-05-19 | Composite multileaf, multistage leaf spring |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1190251A (en) |
-
1981
- 1981-05-19 CA CA000377835A patent/CA1190251A/en not_active Expired
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