Leaf spring

In a leaf spring including a plurality of stacked spring leaves connected to one another at least indirectly at the spring ends to form pairs of contacting friction surfaces between which load-dependent normal friction forces are generated during spring action, the improvement compromising:

• a. a rigid clamping yoke of closed cross section provided at the ends of the leaf spring and surrounding at least two of the stacked spring leaves;
• said rigid clamping yoke including
• 1. a generally U-shaped clamp having spaced legs and a bottom;
• 2. a transverse bar rigidly affixed to said clamp and bridging said legs at a distance from said bottom;
• and
• b. a compression spring disposed within said clamping yoke and comprising, in a unitary structure, two identical, rubber-elastic pads and an intermediate sheet metal plate inserted between said pads in a face-to-face relationship therewith;
• said plate being bonded to both said pads;
• said clamping yoke biasing said compression spring for pressing at least two of said spring leaves to one another at the ends of the leaf spring with an accurately predetermined, load-independent, normal force;
• said load-independent force being applied in addition to said load-dependent force.

In a leaf spring including a plurality of stacked spring leaves connected to one another at least indirectly at the spring ends to form pairs of contacting friction surfaces between which load-dependent normal friction forces are generated during spring action, the improvement comprising:

• a. a rigid clamping yoke of closed cross section provided at the ends of the leaf spring and surrounding at least two of the stacked spring leaves;
• said rigid clamping yoke including
• 1. a generally U-shaped clamp having spaced legs and a bottom;
• each spring leaf, in the zone that is surrounded by said clamping yoke, is narrower than in the remaining spring zone by at least twice the thickness of the clamp legs;
• 2. a transverse bar rigidly affixed to said clamp and bridging said legs at a distance from said bottom;
• and
• b. a compression spring disposed within said clamping yoke;
• said clamping yoke biasing said compression spring for pressing at least two of said spring leaves to one another at the ends of the leaf spring with an accurately predetermined, load-independent, normal force;
• said load-independent force being applied in addition to said load-dependent force.

In a leaf spring including a plurality of stacked spring leaves connected to one another at least indirectly at the spring ends to form pairs of contacting friction surfaces between which load-dependent normal friction forces are generated during spring action;

• each spring leaf having opposite large faces and opposite narrow edge faces;
• the spring leaves being in a face-to-face relationship with their large faces;
• the improvement comprising:
• a. a rigid clamping yoke of closed cross section provided at the ends of the leaf spring and surrounding at least two of the stacked spring leaves;
• said rigid clamping yoke including
• 1. a generally U-shaped clamp having spaced legs and a bottom;
• 2. a transverse bar rigidly affixed to said clamp and bridging said legs at a distance from said bottom;
• b. a rubber-elastic pad disposed within said clamping yoke and having opposite first and second faces and extending, within said clamp, solely over the area of the large spring leaf faces;
• said clamping yoke compressing said rubber-elastic pad for pressing at least two of said spring leaves to one another at the ends of the leaf spring with an accurately predetermined, load-independent, normal force;
• said load-independent force being applied in addition to said load-dependent force;
• and
• c. first and second sheet metal plates each having opposite first and second faces and being disposed in said clamp;
• said first face of said first plate being bonded to said first face of said pad;
• said first face of said second plate being bonded to said second face of said pad, said second face of said second plate engaging unbonded an outer spring leaf of said leaf spring, whereby said pad and said plates are removable as a unit from said clamp upon opening thereof.

In a leaf spring including a plurality of stacked spring leaves connected to one another at least indirectly at the spring ends to form pairs of contacting friction surfaces between which load-dependent normal friction forces are generated during spring action, the improvement comprising:

• a. a rigid clamping yoke of closed cross section provided at the ends of the leaf spring and surrounding at least two of the stacked spring leaves;
• said rigid clamping yoke including
• 1. a generally U-shaped clamp having spaced legs and a bottom;
• 2. a transverse bar rigidly affixed to said clamp and bridging said legs at a distance from said bottom;
• and
• b. a rubber-elastic pad disposed within said clamping yoke and having a face provided with a thickened, raised portion;
• said clamping yoke compressing said rubber-elastic pad for pressing at least two of said spring leaves to one another at the ends of the leaf spring with an accurately predetermined, load-independent, normal force;
• said load-independent force being applied in addition to said load-dependent force.

In a leaf spring including a plurality of stacked spring leaves connected to one another at least indirectly at the spring ends to form pairs of contacting friction surfaces between which load-dependent normal friction forces are generated during spring action;

• one of the spring leaves being a main spring leaf;
• the improvement comprising:
• a. a rigid clamping yoke of closed cross section provided at the ends of the leaf spring and surrounding at least two of the stacked spring leaves;
• said rigid clamping yoke including
• 1. a generally U-shaped clamp having spaced legs and a bottom;
• 2. a transverse bar rigidly affixed to said clamp and bridging said legs at a distance from said bottom;
• and
• b. a compression spring disposed within said clamping yoke and having opposite first and second faces, at least said first face being oriented towards and adjacent to one of said spring leaves;
• said clamping yoke compressing said compression spring for pressing at least two of said spring leaves to one another at the ends of the parabolic leaf spring with an accurately predetermined, load-independent, normal force;
• said load-independent force being applied in addition to said load-dependent force;
• said main spring leaf being affixed to said clamping yoke and extending externally thereof, said main spring leaf having one face oriented towards the pressure side of the spring, said one face of said main spring leaf engaging face-to-face an outer surface of said clamp.

In a method of making a leaf spring including a plurality of stacked spring leaves connected to one another at least indirectly at the spring ends to form pairs of contacting friction surfaces, the improvement comprising the steps of

• a. loading said leaf spring with a force for causing a spring deflection of approximately one half of the maximum spring path;
• b. surrounding at least two of said spring leaves at each spring end with a generally U-shaped clamp;
• c. inserting in the clamp a rubber elastic pad;
• d. placing into the open end of the clamp a transverse bar;
• e. applying an external force of predetermined magnitude to the bar for pressing the bar into the clamp and thus causing compression of said pad to a desired extent;
• and
• f. welding said bar to said clamp during the application of said external force and after said pad has been compressed to the desired extent, whereby said pad permanently exerts a compressing force to the spring leaves surrounded by the clamp and the bar welded thereto.