Descriptive Report of the Invention: "PRESSURIZED FLUID OPERATED SOLID FRICTION SHOCK ABSORBER"

This invention refers to a solid friction shock absorber operated by a pressurized fluid which will enable quick dissipation, through solid friction, of the elastic energy absorbed by vehicles' suspensions.

The function of the shock absorber is to avoid oscillations and undesirable movement of the suspension, keeping the wheels in firm contact with the ground the whole time, thus allowing greater stability, better driving and braking capability of the vehicle. Two basic concepts exist as for the friction type, being them: Viscous friction, dissipates the elastic energy through the friction of a hydraulic oil flowing through galleries and internal valves of the hydraulic shock absorber; Solid friction, dissipates the elastic energy through the friction among two rigid surfaces tightly pressed against each other by springs. The hydraulic shock absorber became, practically, the only available option in the market, due to its reasonable cost when manufactured in large scale, its good operational efficiency and appropriate dimensions for several types of applications.

The spring operated solid friction shock absorber is used in very specific and restricted applications, having high weight due to the need of all the components to be designed to endure the great strains produced by the springs; efficiency loss due to the loss of elasticity of the spring and wear and tear of the pads with time; tuning difficulty due to the great pressure of the spring, that demands special devices and is potentially dangerous; high cost due to difficulties in the production and in the assembly; and being impracticable for use in light vehicles such as automobiles and motorcycles. The main advantages of pressurized fluid operated solid friction shock-absorbers are the ease of production, done by cold stamping, plastic injection, rubber vulcanizing, some or no machining at all; simple concept, robust and with few parts; efficiency, because it doesn't need maintenance until the end of the life time; and versatility, because a single model can be used in a great range of situations just by adjusting the working pressure.

With the intent of solving the aforementioned problems of the spring operated solid friction shock absorber, the pressurized fluid operated solid friction shock absorber of was developed, and will be described in according to the attached illustrations, being that:

FIGURE 01 presents the lateral cut of the pressurized fluid operated solid friction shock absorber;

FIGURE 02 presents the technical drawing of the component parts of the pressurized fluid operated solid friction shock absorber. As it can be observed in the illustrations, the pressurized fluid operated solid friction shock absorber works through a rubber bag of pressurized fluid (6), fed externally by a feeder tube (16) and connected the a hose (18) by a hose adapter (17), which presses three brake shoes (2) with brake linings (5) against the inner wall of the shell (1) of the shock absorber, establishing a force normal to the contact surface between the brake shoe's (2) brake lining (5) and the inner wall of the shell (1). The pressurized fluid bag (6) can be feed by a flask pressurized with the fluid, installed on the shock absorber, or by a compressor, if the vehicle or facility has one.

The brake shoes (2) are mounted on two grippers (3) through fittings, female on the brake shoes (2) and male on the grippers (3), so that they will allow the radial displacement of the brake shoes (2), and compensate the eventual wear and tear of the brake lining (5). The pressurized fluid bag (6) follows the movement of the brake shoes (2), automatically adjusting itself to all the new positions, because it is elastic.

The grippers (3) are firmly mounted onto the shaft (4), of cylindrical shape and with screw threads on both ends, through a fast clamp with restraint pin (21) and the whole group of pressurized fluid bag (6), brake shoes (2), brake linings (5) and grippers (3) will move together with the shaft (4). The movement of the group above described in contact with the inner wall of the shell (I ₅ ) due to the fluid pressure in the bag of pressurized fluid (6), will create the solid friction forces that will dissipate the absorbed elastic energy. The shell (1) has a primary cover (7) with internal screw threads, gasket channel

(22), guide tube (11) for the shaft (4) and guide adapter (15) for the feeder tube (16). It also has a secondary cover (8) to which a mount (13) with rubber cushion (12) is attached.

The shaft (4) has, attached to the end external to the shell (1), a shaft mount (14) with rubber cushion (12) and, fastened to the end internal to the shell (1), a six-sided DIN 934 CL 5.6 nut (19) and a DIN 127 pressure washer that will improve the fastening of the grippers (3). The shaft (4) has a stopper (9) with restraint pin (21), juxtaposed to the gripper (3) closest to the primary cover (7), and a gasket (10) attached to the primary cover (7) through the gasket channel (22).

The pressurized fluid operated solid friction shock absorber will have great applicability in the automotive industry, filling all of the requirements and industrial applicability inherent to the patent grant.