CA1208664A - Vehicle leaf spring suspension - Google Patents
Vehicle leaf spring suspensionInfo
- Publication number
- CA1208664A CA1208664A CA000446805A CA446805A CA1208664A CA 1208664 A CA1208664 A CA 1208664A CA 000446805 A CA000446805 A CA 000446805A CA 446805 A CA446805 A CA 446805A CA 1208664 A CA1208664 A CA 1208664A
- Authority
- CA
- Canada
- Prior art keywords
- leaf spring
- assembly
- vehicle
- frame
- spring assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G11/00—Resilient suspensions characterised by arrangement, location or kind of springs
- B60G11/32—Resilient suspensions characterised by arrangement, location or kind of springs having springs of different kinds
- B60G11/34—Resilient suspensions characterised by arrangement, location or kind of springs having springs of different kinds including leaf springs
- B60G11/38—Resilient suspensions characterised by arrangement, location or kind of springs having springs of different kinds including leaf springs and also rubber springs
Abstract
ABSTRACT
The invention is an improvement to that type of vehicle leaf spring suspension that comprises both a first leaf spring assembly supporting a vehicle body off an axle and a second leaf spring assembly mounted thereabove and adapted to transmit excess vehicle loading to a pair of brackets fixed to the body.
The invention comprises such a leaf spring suspension with a pair of resilient elements mounted between the first and second assemblies to reduce the amplitude of motion of the vehicle body.
The invention is an improvement to that type of vehicle leaf spring suspension that comprises both a first leaf spring assembly supporting a vehicle body off an axle and a second leaf spring assembly mounted thereabove and adapted to transmit excess vehicle loading to a pair of brackets fixed to the body.
The invention comprises such a leaf spring suspension with a pair of resilient elements mounted between the first and second assemblies to reduce the amplitude of motion of the vehicle body.
Description
~2~
This lnvention relates to a leaf spring suspension and more particularly, to that type of leaf spring suspension having a main leaf spring assembly and a connected secondary leaf spring assembly.
Many vehicles incorporate a leaf spring assembly for suspending the vehicle on its rear axle. Leaf spring assemblies usually comprise a series of overlying leaf springs of differing lengths secured together at a point central of their length by means attaching them to the rear axle of the vehicle. Usually, the longest of t~e leaf springs of the assembly has its ends secured to the frame of the vehicle. One end of that leaf spring is pivotally secured ~o the frame and the other end is secured by means of a pivotal linkage, ~hat linkage allowing for variations in the lengths of the leaf spring assembly under various loads. When the vehicle has a heavy load the curvature of the leaf spring assembly decreases and the straight-line distance bet~een the ends of the assembly increase. Corres-pondingly, when the load is remove~ the curvature of the leaf spring assembly increases and the straight-line distance between the ends of the assembly decreases.
The basic construction of a leaf spring assembly for a vehicle suspension has been long known, and lea~ s~riDg su~pensions are also known which utilize a sec~n~ary leaf spring means in cooperation with the primary assembly. For instance, United States Patent No. 2,826,407, granted to W.A. Scheubleinl Jr., et al.
on March 11, 1958, discloses an overload spring for a vehicle, which spring is secured to the existing leaf spring assembly of a vehicle. The overload spring of that reference is generally ,- ~r,.
~86~
C-shaped and is secured on its back symmetrically above the existing leaf spring assembly of the vehicle. A rubber pad is fixed to each end of the overload spring and each pad is adapted when the vehicle is heavily-loaded to abut against a respective 5 flange secured to the vehicle frame.
United States Patent No. 2,188,689, granted to F.W. Marco on January 30, 1940, discloses a leaf spring suspension system utilizing two generally-parallel leaf spring assemblies. The upper assembly has its center secured to the vehicle axle and 10 its outer ends pivotally secured to the vehicle frame. The secondary leaf spring assembly, which is mounted below the other assembly, also has its center connected to the axle of the vehicle but has its ends normally freely terminating under the other leaf spring assembly. When a heavy load is placed on the vehicle, 15 the curvature of the main leaf spring assembly decreases and the ends of the secondary leaf spring assembly come into contact with the first asse.mbly. The resulting configuration is a single spring assembly in which the leaf springs of both the main and secondary leaf spring assemblies act as one. Thus, 20 with lighter loads the main leaf spring assembly acts alone to more effectively cushion vibration, but under increased loads the number of spring leafs in the assembly is increased for improved load support. A similar onstruction is disclosed in U.S. Patent No. 3,672,656, granted to Saitoh et al.on June 27, 25 lg72.
The subject invention is a spring leaf suspension for a vehicle, comprising main and secondary leaf spring assemblies which interact to not only improve the load-carrying capacity of the vehicle but also to dampen any movement of the axle away 30 from the frame. The ~ain ~eaf spring ~ss~mbly ~om~rises a series cf leaf springs i~ parallel overlying relationship.
That assembly is attached at a position proximate of its center to the axle and has one of its ends directly pivotally attached to the vehicle frame and the other of its ends 35 attached to the vehicle frame through a pivotal linkage.
The secondary leaf spring assembly comprises at least one leaf spring and has a more arcuate profile than the main assembly. The two assemblies are connected together centrally of their length such that they Elex in the same plane, the secondary asse~bly having an operative position above the main assembly on the vehicle. A pair of brackets is secured to the frame of the vehicle, each bracket being positioned on the frame such that a respective end of the second leaf spring assembly comes into contact with that bracket when the vehicle is loaded to a substantial portion of its weight capacity. The leaf spring suspension of the subject invention further comprises a pair of resilient elements, each element ~eing positioned between the first leaf spring assembly and the second leaf spring assembly. One element is positioned between the point of connection of the assemblies and one of their ends, and the other element is pssitioned between that point of connection and the other of their ends, the addition of the elements resulting in a reduced amplitude of motion of the body of the vehicle.
The secondary leaf spring assembly of the suspension of the invention may be comprised of two leaf springs, one of those springs being longer than the other. The ends of the longer leaf 2G spring are adapted to contact the pair of brackets, that longer spring being that part of the secondary assembly in contact with the pair of resillent elements. ~ach resilient element may be a six-sided body formed from rubber and comprising t~o oppositely-positioned arcuate surfaces and four generally planar orthogonal sides extending betweenthe arcua~e surface.
The element is formed such that one of the arcuate surfaces has a curvature corresponding to that on the upper surface of the first leaf spring assembly when little or no load is present on the vehicle, and the o~her arcua~e surface has a curvature corresponding to that on the lower surface of the second leaf spring assembly when little or no load is present on the vehicle.
In a further form, the invention is a six-sided block of resilient material adapted to be utilized on a vehicle having a leaf spring suspension with a first leaf spring assembly and a second lea~ spring assembly. The second assembly is operatively positioned above the first assembly9 and is centrally connected to a rear axle assembly of the vehicle and ~ii6~
has its ends connected to the frame of the vehicle. The second assembly is centrally connected to the center of the first assembly and has its ends adapted to contact support flanges on the frame of the vehicle when the vehicle is loaded to a 5 substantial portion of its welght capacity. The block of resilient material in this form of the invention has two oppositely-positioned arcuate surfaces and four generally planar orthogonal sides extending between the arcuate surfaces.
One arcuate surface is a contour corresponding to that on the 10 upper surface of the first leaf spring assembly when little or no load is on the vehicle and the arcuate surface has a contour corresponding to that of the lower surface of the secondly spring assembly when little or no load is on the vehicle. The block may be positioned between the two leaf spring assemblies 15 to reduce the amplitude of motion of the vehicle body.
The leaf spring suspension of the subject invention will next be described in terms of a preferred embodiment utilizing the accompanying drawings, in which:
Figure 1 is a side view of ~he leaf spring suspension of 20 the subject invention, the vehicle supported by the suspension being lightly loaded such that the secondary leaf spring assembly is not bearing a portion of the vehicle load.
Figure 2 is a side view of the leaf spring suspension of the sub~ect invention, the vehicle supported by the suspension 25 being heavily loaded such that the secondary leaf spring assembly is bearing a portion of the vehicle load.
Figure 3 is a side view of the leaf spring suspension of the subject invention, the secondary leaf spring assembly bearing a load as the main spring assembly acts to move away 30 from the frame.
Figure 4 is a perspective view of one of the resilient elements utilized in the suspension of the subject invention.
With reference to Figure 19 a leaf spring suspension generally designated 10 supports the frame, generally 35 designated 11, of a vehicle off of the rear axle 12 of the vehicle. The suspension ln comprises a main leaf spring assembly 15 and a secondary leaf spring assembly 16, the secondary ... . .
assembly 16 assisting main assembly 15 during periods of increased loading of the vehicle. Main assembly 15 is comprised of a series of leaf springs mounted in overlying abutment, the leaf springs being of staggered lengths with the shortest spring 17 being most proximate to axle housing 12 and the longest spring 18 being most proximate to and connected to frame 11. The five leaf springs most adjacent to longest spring 18 have their ends held together by a pair of spring clamps 19. Each clamp 19 is rivetted under the fifth leaf spring and overlaps spring 18.
The series of leaf springs that comprise first assembly 15 each have a centrally-located hole e~tending therethrough, the holes being in alignment in assembly 15 with a bolt ~shown in outline as 20) extending therethrough. The bolt 20 which holds together leaf spring suspension 10, also extends through a central hole in both of the leaf springs that comprise secondary assembly 16 and through a hole in spacer bracket 21 which spaces the secondary assembly from ~he main assembly.
As shown in Figure 1, the longest and uppermost leaf spring 18 of main assembly 15 has its one end pivotally secured to a support bracket 25 positioned on frame 11 at the forward end of suspension 10. A similar support bracket 26 is secured to frame 11 adjacent the rearward end of suspension 10, and a link 27 has its one end pivotally connected to support bracket 26 and its other end pivotally secured to the rearward end of leaf spring 18.
The main leaf spring assembly 15 is supported on a plate 28 which has one arcuate surface configured to, and integrally connected to, the outer surface of axle housing 12 and an opposite flat surface upon which rests the central portion of the underside of the shortest, lowermost leaf spring 17. Spacer bracket 21 has a pair of opposite flat surfaces, a lower surface which rests upon the central portion of the upper surface of leaf spring 18 and an opposite upper surface upon which rests the central portion of the underside of the lowermost, larger leaf spring 29 of secondary assembly 16. A top bracket 30 has a flat lower surface upon which rests the central portion of the upper surface of the upper-most, shorter leaf spring 31 of secondary assembly 16. A recess on that one surface of top bracket 30 surrounds a nut on the end of bolt 20, the head of bolt 20 sitting in a recess in the flat surface of plate 28; the leaf spring suspension 10 is thereby centred ove.
axle housing 12. Top bracket 30 has a pair of ears 32 around each of which extend the base portion of a respective U-bolt 33, the ends of the pair of U-bolts 33 extending below axle housing 12 and being connected by a plate 34 resting against the underside of axle housing 12. A flange 35 extends downwardly from plate 34 to support a torsion bar 36 having its one end secured to frame 11.
Leaf springs 29 and 31, which together comprise secondary assembly 16 are more arcuately contoured than the leaf springs of maln assembly 15. As shown in Figure 1, leaf spring 29, the longer of the two leaf springs of assembly 16, has each of its ends spaced from a respective one of the brackets 40 on frame 11 when the vehicle is carrying little or no load. A pair of resilient blocks 41 are positioned between the first and second leaf spring assemblies of suspension 10. Each block 41 is formed from LINETEX* or PCV-CN+S rubber. The top surface of each block 41 is arcuate to correspond with the contour on the underside of leaf spring 29, the top surface of each block 41 being approximately 7.5 inches long and 3~0 inches wide. The bottom surface of each block 41 ls also arcuate and corresponds with the contour on the top surface of leaf spring 18, the bottom surface of each block 41 also being approximately 7.5 inches long and 3.0 inches wide. Block 41 is approximately 2.5 inches thick at its large end and 1.5 inches thick at its small end.
Blocks 41 may be formed from a single piece of rubber or may be formed from a number of bonded rubber layers. As can be seen in Figure 4, blocks 41 are each six-sided with one of the pair of oppositely-positioned sides being arcuate and the other four sides being generally planar and orthogonal to each other. The less arcuate of the two arcuate surfaces is configured * Trademark such that its contour corresponds to that on the upper surface of leaf spring 18. The more arcuate opposite surface of block 41 has a contour corresponding to that on the lower surface of leaf spring 29. The curvature of the ascuate surfaces of block 41 correspond to those on leaf springs 18 and 29 when little or no load is present on the vehicle, i.e. when the ends of leaf spring 29 are spaced from the pair of brackets 40 on frame 11.
Figures 1, 2 and 3 illustrate respectively the configuration of suspension 10 when axle housing 12 is in its normal rest position relative to frame 11 (little or no load present on the vehicle), when axle housing 12 is more proximate of frame 11 than initsrest position (for instance, when a heavy load is present on the vehicle or the vehicle moves over an obstacle in its path), and when axle housing 12 is further from frame 11 than its rest position (for instance, when the rear wheel of the vehicle is moving across a depression in its path).
In Figure 2, the outer ends of leaf spring 29 are in abutment with the pair of brackets 40 and the resilient blocks 41 are compressed by the resulting decrease in the curvature of the secondary leaf spring assembly 16. Main leaf spring assembly 15 also has a decreased curvature over that assumed when it is in its rest position. In the configuration of Figure 2, resilient blocks 41 serve several functions. Firstly, they absorb a portion of the energy from secondary leaf spring assembly 16 and thus in effect act as shock absorbers to cushion the forces experienced in secondary assembly 16~ Also~ blocks 41 provide support to secondary assembly 1~ which reduces the flexure on that assembly and the possibility of fatigue fracture. From tests conducted, it has been found that the presence of blocks 41 and the flat surfaces on brackets 21 and 30 and on plate 28 has resulted in a significant decrease in fatigue fractures of leaf springs positioned as at 29 and 31. Rubber stop member 42 (see Figure 4) secured to frame 11 is brought into abutment wi~h axle housing 12 and limits the upward movement of axle housing 12 relative to frame 11.
With reference to Figure 3, resilient blocks 41 also act to cushion the vibration experienced when axle housing 12 moves further from frame 11 relative to the rest position illustrated in Figure 1. Because secondary leaf spring assembly 16 acts against increasing its curvature, main leaf spring assembly 15 cannot increase its curvature to the extent that it would if blocks 41 were not present. In this regard, the pair of spring clamps 19 prevent the four leaf springs adjacent to leaf spring 18 on main assembly 15 from moving independently of spring 18. Thus, the blocks 41 have a similar cushioning effect in this configuration as they do in the configuration of Figure 2. The blocks act as a shock absorber to reduce the vibration in suspenion 10 and lower the amplitude oE motion of axle housing 12 relative to frame 11.
The subject invention is installed in the following manner.
The nuts are removed from the pair of U-bolts 33 3 and the rear end of the vehicle is then raised to remove loading on the rear axle. Top bracket 30 is then removed, and the nut on the bolt to be replaced by bolt 20 is removed. The two springs 29 and 31 are then removed. Main leaf spring assembly 15 israised from plate 28 to allow the original bolt to be replaced by bolt 20 which is approximately 1.5 inches longer. The pair of blocks 41 are then positioned on the top surface of spring 18 before springs 29 and 31 and plate 30 are placed back in position. The weight of the vehicle is then lowered onto the rear axle, and a pair of nuts then tightened together on bol~ 20 (tightening one bolt only would strip its thread). After tightening, the end nut is removed from bolt 20 and the protruding portion of bolt 20 is cut off. Plate 30 is then repositioned, and U-bolts 33 are secured.
The subject invention can be easily and quickly ~dapted to the double leaf spring assembly suspensions of pick-up trucks, camper vehicles, and other vehicles. The addition of a pair of resilient blocks to such suspensions is performed very quickly and at little expense, and resul~s in significantly smoother motion of the vehicle.
This lnvention relates to a leaf spring suspension and more particularly, to that type of leaf spring suspension having a main leaf spring assembly and a connected secondary leaf spring assembly.
Many vehicles incorporate a leaf spring assembly for suspending the vehicle on its rear axle. Leaf spring assemblies usually comprise a series of overlying leaf springs of differing lengths secured together at a point central of their length by means attaching them to the rear axle of the vehicle. Usually, the longest of t~e leaf springs of the assembly has its ends secured to the frame of the vehicle. One end of that leaf spring is pivotally secured ~o the frame and the other end is secured by means of a pivotal linkage, ~hat linkage allowing for variations in the lengths of the leaf spring assembly under various loads. When the vehicle has a heavy load the curvature of the leaf spring assembly decreases and the straight-line distance bet~een the ends of the assembly increase. Corres-pondingly, when the load is remove~ the curvature of the leaf spring assembly increases and the straight-line distance between the ends of the assembly decreases.
The basic construction of a leaf spring assembly for a vehicle suspension has been long known, and lea~ s~riDg su~pensions are also known which utilize a sec~n~ary leaf spring means in cooperation with the primary assembly. For instance, United States Patent No. 2,826,407, granted to W.A. Scheubleinl Jr., et al.
on March 11, 1958, discloses an overload spring for a vehicle, which spring is secured to the existing leaf spring assembly of a vehicle. The overload spring of that reference is generally ,- ~r,.
~86~
C-shaped and is secured on its back symmetrically above the existing leaf spring assembly of the vehicle. A rubber pad is fixed to each end of the overload spring and each pad is adapted when the vehicle is heavily-loaded to abut against a respective 5 flange secured to the vehicle frame.
United States Patent No. 2,188,689, granted to F.W. Marco on January 30, 1940, discloses a leaf spring suspension system utilizing two generally-parallel leaf spring assemblies. The upper assembly has its center secured to the vehicle axle and 10 its outer ends pivotally secured to the vehicle frame. The secondary leaf spring assembly, which is mounted below the other assembly, also has its center connected to the axle of the vehicle but has its ends normally freely terminating under the other leaf spring assembly. When a heavy load is placed on the vehicle, 15 the curvature of the main leaf spring assembly decreases and the ends of the secondary leaf spring assembly come into contact with the first asse.mbly. The resulting configuration is a single spring assembly in which the leaf springs of both the main and secondary leaf spring assemblies act as one. Thus, 20 with lighter loads the main leaf spring assembly acts alone to more effectively cushion vibration, but under increased loads the number of spring leafs in the assembly is increased for improved load support. A similar onstruction is disclosed in U.S. Patent No. 3,672,656, granted to Saitoh et al.on June 27, 25 lg72.
The subject invention is a spring leaf suspension for a vehicle, comprising main and secondary leaf spring assemblies which interact to not only improve the load-carrying capacity of the vehicle but also to dampen any movement of the axle away 30 from the frame. The ~ain ~eaf spring ~ss~mbly ~om~rises a series cf leaf springs i~ parallel overlying relationship.
That assembly is attached at a position proximate of its center to the axle and has one of its ends directly pivotally attached to the vehicle frame and the other of its ends 35 attached to the vehicle frame through a pivotal linkage.
The secondary leaf spring assembly comprises at least one leaf spring and has a more arcuate profile than the main assembly. The two assemblies are connected together centrally of their length such that they Elex in the same plane, the secondary asse~bly having an operative position above the main assembly on the vehicle. A pair of brackets is secured to the frame of the vehicle, each bracket being positioned on the frame such that a respective end of the second leaf spring assembly comes into contact with that bracket when the vehicle is loaded to a substantial portion of its weight capacity. The leaf spring suspension of the subject invention further comprises a pair of resilient elements, each element ~eing positioned between the first leaf spring assembly and the second leaf spring assembly. One element is positioned between the point of connection of the assemblies and one of their ends, and the other element is pssitioned between that point of connection and the other of their ends, the addition of the elements resulting in a reduced amplitude of motion of the body of the vehicle.
The secondary leaf spring assembly of the suspension of the invention may be comprised of two leaf springs, one of those springs being longer than the other. The ends of the longer leaf 2G spring are adapted to contact the pair of brackets, that longer spring being that part of the secondary assembly in contact with the pair of resillent elements. ~ach resilient element may be a six-sided body formed from rubber and comprising t~o oppositely-positioned arcuate surfaces and four generally planar orthogonal sides extending betweenthe arcua~e surface.
The element is formed such that one of the arcuate surfaces has a curvature corresponding to that on the upper surface of the first leaf spring assembly when little or no load is present on the vehicle, and the o~her arcua~e surface has a curvature corresponding to that on the lower surface of the second leaf spring assembly when little or no load is present on the vehicle.
In a further form, the invention is a six-sided block of resilient material adapted to be utilized on a vehicle having a leaf spring suspension with a first leaf spring assembly and a second lea~ spring assembly. The second assembly is operatively positioned above the first assembly9 and is centrally connected to a rear axle assembly of the vehicle and ~ii6~
has its ends connected to the frame of the vehicle. The second assembly is centrally connected to the center of the first assembly and has its ends adapted to contact support flanges on the frame of the vehicle when the vehicle is loaded to a 5 substantial portion of its welght capacity. The block of resilient material in this form of the invention has two oppositely-positioned arcuate surfaces and four generally planar orthogonal sides extending between the arcuate surfaces.
One arcuate surface is a contour corresponding to that on the 10 upper surface of the first leaf spring assembly when little or no load is on the vehicle and the arcuate surface has a contour corresponding to that of the lower surface of the secondly spring assembly when little or no load is on the vehicle. The block may be positioned between the two leaf spring assemblies 15 to reduce the amplitude of motion of the vehicle body.
The leaf spring suspension of the subject invention will next be described in terms of a preferred embodiment utilizing the accompanying drawings, in which:
Figure 1 is a side view of ~he leaf spring suspension of 20 the subject invention, the vehicle supported by the suspension being lightly loaded such that the secondary leaf spring assembly is not bearing a portion of the vehicle load.
Figure 2 is a side view of the leaf spring suspension of the sub~ect invention, the vehicle supported by the suspension 25 being heavily loaded such that the secondary leaf spring assembly is bearing a portion of the vehicle load.
Figure 3 is a side view of the leaf spring suspension of the subject invention, the secondary leaf spring assembly bearing a load as the main spring assembly acts to move away 30 from the frame.
Figure 4 is a perspective view of one of the resilient elements utilized in the suspension of the subject invention.
With reference to Figure 19 a leaf spring suspension generally designated 10 supports the frame, generally 35 designated 11, of a vehicle off of the rear axle 12 of the vehicle. The suspension ln comprises a main leaf spring assembly 15 and a secondary leaf spring assembly 16, the secondary ... . .
assembly 16 assisting main assembly 15 during periods of increased loading of the vehicle. Main assembly 15 is comprised of a series of leaf springs mounted in overlying abutment, the leaf springs being of staggered lengths with the shortest spring 17 being most proximate to axle housing 12 and the longest spring 18 being most proximate to and connected to frame 11. The five leaf springs most adjacent to longest spring 18 have their ends held together by a pair of spring clamps 19. Each clamp 19 is rivetted under the fifth leaf spring and overlaps spring 18.
The series of leaf springs that comprise first assembly 15 each have a centrally-located hole e~tending therethrough, the holes being in alignment in assembly 15 with a bolt ~shown in outline as 20) extending therethrough. The bolt 20 which holds together leaf spring suspension 10, also extends through a central hole in both of the leaf springs that comprise secondary assembly 16 and through a hole in spacer bracket 21 which spaces the secondary assembly from ~he main assembly.
As shown in Figure 1, the longest and uppermost leaf spring 18 of main assembly 15 has its one end pivotally secured to a support bracket 25 positioned on frame 11 at the forward end of suspension 10. A similar support bracket 26 is secured to frame 11 adjacent the rearward end of suspension 10, and a link 27 has its one end pivotally connected to support bracket 26 and its other end pivotally secured to the rearward end of leaf spring 18.
The main leaf spring assembly 15 is supported on a plate 28 which has one arcuate surface configured to, and integrally connected to, the outer surface of axle housing 12 and an opposite flat surface upon which rests the central portion of the underside of the shortest, lowermost leaf spring 17. Spacer bracket 21 has a pair of opposite flat surfaces, a lower surface which rests upon the central portion of the upper surface of leaf spring 18 and an opposite upper surface upon which rests the central portion of the underside of the lowermost, larger leaf spring 29 of secondary assembly 16. A top bracket 30 has a flat lower surface upon which rests the central portion of the upper surface of the upper-most, shorter leaf spring 31 of secondary assembly 16. A recess on that one surface of top bracket 30 surrounds a nut on the end of bolt 20, the head of bolt 20 sitting in a recess in the flat surface of plate 28; the leaf spring suspension 10 is thereby centred ove.
axle housing 12. Top bracket 30 has a pair of ears 32 around each of which extend the base portion of a respective U-bolt 33, the ends of the pair of U-bolts 33 extending below axle housing 12 and being connected by a plate 34 resting against the underside of axle housing 12. A flange 35 extends downwardly from plate 34 to support a torsion bar 36 having its one end secured to frame 11.
Leaf springs 29 and 31, which together comprise secondary assembly 16 are more arcuately contoured than the leaf springs of maln assembly 15. As shown in Figure 1, leaf spring 29, the longer of the two leaf springs of assembly 16, has each of its ends spaced from a respective one of the brackets 40 on frame 11 when the vehicle is carrying little or no load. A pair of resilient blocks 41 are positioned between the first and second leaf spring assemblies of suspension 10. Each block 41 is formed from LINETEX* or PCV-CN+S rubber. The top surface of each block 41 is arcuate to correspond with the contour on the underside of leaf spring 29, the top surface of each block 41 being approximately 7.5 inches long and 3~0 inches wide. The bottom surface of each block 41 ls also arcuate and corresponds with the contour on the top surface of leaf spring 18, the bottom surface of each block 41 also being approximately 7.5 inches long and 3.0 inches wide. Block 41 is approximately 2.5 inches thick at its large end and 1.5 inches thick at its small end.
Blocks 41 may be formed from a single piece of rubber or may be formed from a number of bonded rubber layers. As can be seen in Figure 4, blocks 41 are each six-sided with one of the pair of oppositely-positioned sides being arcuate and the other four sides being generally planar and orthogonal to each other. The less arcuate of the two arcuate surfaces is configured * Trademark such that its contour corresponds to that on the upper surface of leaf spring 18. The more arcuate opposite surface of block 41 has a contour corresponding to that on the lower surface of leaf spring 29. The curvature of the ascuate surfaces of block 41 correspond to those on leaf springs 18 and 29 when little or no load is present on the vehicle, i.e. when the ends of leaf spring 29 are spaced from the pair of brackets 40 on frame 11.
Figures 1, 2 and 3 illustrate respectively the configuration of suspension 10 when axle housing 12 is in its normal rest position relative to frame 11 (little or no load present on the vehicle), when axle housing 12 is more proximate of frame 11 than initsrest position (for instance, when a heavy load is present on the vehicle or the vehicle moves over an obstacle in its path), and when axle housing 12 is further from frame 11 than its rest position (for instance, when the rear wheel of the vehicle is moving across a depression in its path).
In Figure 2, the outer ends of leaf spring 29 are in abutment with the pair of brackets 40 and the resilient blocks 41 are compressed by the resulting decrease in the curvature of the secondary leaf spring assembly 16. Main leaf spring assembly 15 also has a decreased curvature over that assumed when it is in its rest position. In the configuration of Figure 2, resilient blocks 41 serve several functions. Firstly, they absorb a portion of the energy from secondary leaf spring assembly 16 and thus in effect act as shock absorbers to cushion the forces experienced in secondary assembly 16~ Also~ blocks 41 provide support to secondary assembly 1~ which reduces the flexure on that assembly and the possibility of fatigue fracture. From tests conducted, it has been found that the presence of blocks 41 and the flat surfaces on brackets 21 and 30 and on plate 28 has resulted in a significant decrease in fatigue fractures of leaf springs positioned as at 29 and 31. Rubber stop member 42 (see Figure 4) secured to frame 11 is brought into abutment wi~h axle housing 12 and limits the upward movement of axle housing 12 relative to frame 11.
With reference to Figure 3, resilient blocks 41 also act to cushion the vibration experienced when axle housing 12 moves further from frame 11 relative to the rest position illustrated in Figure 1. Because secondary leaf spring assembly 16 acts against increasing its curvature, main leaf spring assembly 15 cannot increase its curvature to the extent that it would if blocks 41 were not present. In this regard, the pair of spring clamps 19 prevent the four leaf springs adjacent to leaf spring 18 on main assembly 15 from moving independently of spring 18. Thus, the blocks 41 have a similar cushioning effect in this configuration as they do in the configuration of Figure 2. The blocks act as a shock absorber to reduce the vibration in suspenion 10 and lower the amplitude oE motion of axle housing 12 relative to frame 11.
The subject invention is installed in the following manner.
The nuts are removed from the pair of U-bolts 33 3 and the rear end of the vehicle is then raised to remove loading on the rear axle. Top bracket 30 is then removed, and the nut on the bolt to be replaced by bolt 20 is removed. The two springs 29 and 31 are then removed. Main leaf spring assembly 15 israised from plate 28 to allow the original bolt to be replaced by bolt 20 which is approximately 1.5 inches longer. The pair of blocks 41 are then positioned on the top surface of spring 18 before springs 29 and 31 and plate 30 are placed back in position. The weight of the vehicle is then lowered onto the rear axle, and a pair of nuts then tightened together on bol~ 20 (tightening one bolt only would strip its thread). After tightening, the end nut is removed from bolt 20 and the protruding portion of bolt 20 is cut off. Plate 30 is then repositioned, and U-bolts 33 are secured.
The subject invention can be easily and quickly ~dapted to the double leaf spring assembly suspensions of pick-up trucks, camper vehicles, and other vehicles. The addition of a pair of resilient blocks to such suspensions is performed very quickly and at little expense, and resul~s in significantly smoother motion of the vehicle.
Claims (4)
1. A leaf spring suspension for supporting a vehicle body on an axle of the vehicle, the suspension extending between a frame of the vehicle and the axle, the suspension comprising:
a) a first leaf spring assembly, comprising a series of leaf springs in parallel overlying relationship, that assembly being attached at a position proximate of its centre to the axle, one end of that assembly being directly pivotally attached to the vehicle frame and the other end of that assembly being attached to the vehicle frame through a pivotal linkage;
b) a second leaf spring assembly, comprising at least one leaf spring, the second assembly having a more arcuate profile than the first assembly, the first and second assemblies being connected together centrally of their length such that those assemblies flex in the same plane, the second assembly having an operative position above the first assembly on the vehicle;
c) a pair of brackets secured to the frame of the vehicle, each bracket being positioned on the frame such that a respective end of the second leaf spring assembly comes into contact with that bracket when the vehicle is loaded to a substantial portion of its weight capacity, and d) a pair of resilient elements, each resilient element being positioned between the first leaf spring assembly and the second leaf spring assembly such that one resilient element is positioned between the point of connection of the assemblies and one of their ends and the other resilient element is positioned between that point of connection and the other of their ends, the addition of the resilient elements resulting in a reduced amplitude of motion of the vehicle body.
a) a first leaf spring assembly, comprising a series of leaf springs in parallel overlying relationship, that assembly being attached at a position proximate of its centre to the axle, one end of that assembly being directly pivotally attached to the vehicle frame and the other end of that assembly being attached to the vehicle frame through a pivotal linkage;
b) a second leaf spring assembly, comprising at least one leaf spring, the second assembly having a more arcuate profile than the first assembly, the first and second assemblies being connected together centrally of their length such that those assemblies flex in the same plane, the second assembly having an operative position above the first assembly on the vehicle;
c) a pair of brackets secured to the frame of the vehicle, each bracket being positioned on the frame such that a respective end of the second leaf spring assembly comes into contact with that bracket when the vehicle is loaded to a substantial portion of its weight capacity, and d) a pair of resilient elements, each resilient element being positioned between the first leaf spring assembly and the second leaf spring assembly such that one resilient element is positioned between the point of connection of the assemblies and one of their ends and the other resilient element is positioned between that point of connection and the other of their ends, the addition of the resilient elements resulting in a reduced amplitude of motion of the vehicle body.
2. A leaf spring suspension as in claim 1, wherein the second leaf spring assembly comprises two leaf springs, one of those springs being longer than the other, the longer leaf spring having its ends adapted to contact the pair of brackets, that longer spring being that part of the second assembly in contact with the pair of resilient elements.
3. A leaf spring suspension as in claim 1 or 2, wherein each resilient element is a six-sided body formed from rubber and comprising two oppositely-positioned arcuate surfaces and four generally planar orthogonal sides extending between the arcuate surfaces, the element being formed such that one of the arcuate surfaces has a curvature corresponding to that on the upper surface of the first leaf spring assembly when little or no load is on the vehicle and the other arcuate surface has a curvature corresponding to that on the lower surface of the second leaf spring assembly when little or no load is on the vehicle.
4. A six-sided block of resilient material adapted to be utilized on a vehicle having a leaf spring suspension with a first leaf spring assembly and a second leaf spring assembly, the second assembly being operatively positioned above the first assembly, the first assembly being centrally connected to a rear axle assembly of the vehicle and having its ends connected to a frame of the vehicle, the second assembly being centrally connected to the center of the first assembly and having its ends adapted to contact support flanges on the frame of the vehicle when the vehicle is loaded to a sub-stantial portion of its weight capacity, the block of resilient material having two oppositely-positioned arcuate surfaces and four generally planar orthogonal sides extending between the arcuate surfaces, one arcuate surface having a contour corres-ponding to that on the upper surface of the first leaf spring assembly when no load is on the vehicle and the other arcuate surface having a contour corresponding to that on the lower surface of the second leaf spring assembly when no load is on the vehicle, whereby the block may be positioned between the two leaf spring assemblies to reduce the amplitude of motion of the vehicle body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000446805A CA1208664A (en) | 1984-02-06 | 1984-02-06 | Vehicle leaf spring suspension |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000446805A CA1208664A (en) | 1984-02-06 | 1984-02-06 | Vehicle leaf spring suspension |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1208664A true CA1208664A (en) | 1986-07-29 |
Family
ID=4127117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000446805A Expired CA1208664A (en) | 1984-02-06 | 1984-02-06 | Vehicle leaf spring suspension |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1208664A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5035406A (en) * | 1989-03-09 | 1991-07-30 | Moog Automotive, Inc. | Variable rate secondary spring for a primary leaf suspension spring |
-
1984
- 1984-02-06 CA CA000446805A patent/CA1208664A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5035406A (en) * | 1989-03-09 | 1991-07-30 | Moog Automotive, Inc. | Variable rate secondary spring for a primary leaf suspension spring |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |