A double-acting drum brake with brake shoe linings that simultaneously engage with the outer and inner drum surfaces.

Abstract

A double-acting drum brake, which has brake shoe linings that engage simultaneously with the outer and inner surfaces of a drum (1), comprises two pairs of brake shoes, each having an inner brake shoe (3) with an inner brake shoe lining (13) and an outer brake shoe (2) with an outer brake shoe lining (12), wherein each pair of brake shoes is connected to a set of mirror-shaped levers (4, 41), each being a lever of the first class (14), and the pivot point (15) of the lever of the first class is fixed to the stationary part of the braking device. A lever of a first class (14) and a lever of a second class (16) are fixedly connected, the pivot point (17) of the lever of the second class also consists of the lever of the second class (16), which is fixedly connected to the stationary part of the braking device, the end of the longer arm of the lever of the first class (14) is connected to the end of the longer arm of the lever of the second class (16) using a sliding pivot hinge, and the lever of the first class (14) is fixed to the pivot point of the lever of the first class in its shorter arm A first outer pin (18) spaced apart from (15) is pivotably connected to the first end of the outer brake shoe (2), and a first inner pin (19) is pivotably connected to the first end of the inner brake shoe (3) on the opposite side of the pivot point (15) of the first class lever, i.e., on the opposite side of the first outer pin (18), and a second class lever (16) in its shorter arm is pivotally connected to the outer brake shoe (2) using a second outer pin (20) spaced apart from the pivot point (17) of the second class lever. The second end of the lever is pivotably connected to the other end of the inner brake shoe (3) using the second inner pin (21) on the opposite side of the pivot point (17) of the lever of the second class, i.e., opposite the second outer pin (20), and in the space between the mirror-like pairs of levers (4, 41) the brake cylinder (6) is positioned so as to be fixedly connected to the stationary part of the braking device, and this is always in place between the first inner pin (19) and the end of the longer arm of the lever of the first class (14) both pairs of levers (4,To act on and extend one lever (14) of each of the first class (41), it has two actuators (5) that are expandable in opposing directions, and in the space between the mirror-like pairs of levers (4, 41), a return spring (24) is positioned to pull the one lever (16) of the second class of both pairs of levers (4, 41) toward each other, and is always mounted in place between a second inner pin (20) and the end of the longer arm of the second first class lever (16).

Description

Technical Field

[0001] Background of the Invention The present invention relates to a rotating device having two pairs of brake shoes, for example a drum brake for braking the wheels or a machine shaft of a motorcycle or an automobile, each of both pairs of brake shoes always consisting of an inner brake shoe provided with an inner brake shoe lining which is pressed against the inner drum surface when braking, and an outer brake shoe provided with an outer brake shoe lining which is pressed against the outer drum surface when braking.

Background Art

[0002] Description of the Prior Art From British Patent No. 1020215, a drum brake is known for this purpose, having brake shoes which are axially directed and contracted within a brake caliper and which engage simultaneously with the outer and inner cylindrical surfaces of the drum. The outer friction lining which engages with the outer friction surface of the drum is fastened to one side face of the brake caliper, the brake caliper is welded to one end of a lever, the second end of the lever is rotatably mounted on a stationary plate using a pin, and the inner friction lining which engages with the inner friction surface of the drum is controlled by a mechanism consisting of a piston and a cylinder contracted on the other side face of the brake caliper. During the movement of the piston, the inner friction lining is pressed against the inner friction surface of the drum, which is carried in the direction in which the drum moves, thereby causing a self-locking effect via the rotation of the lever carrying the brake caliper. This solution tends to cause uneven wear of the brake lining.

[0003] A drum brake having a pair of friction linings positioned on radially opposing drum surfaces that engage together with the outer and inner surfaces of the drum is known from British Patent No. 1137062. This drum brake also has a rotatably mounted caliper, and during piston activity, the inner friction lining is pressed against the inner friction surface of the drum, which is supported in the direction of the drum's movement, thereby providing a self-locking effect. An automatic adjustment mechanism is located on a lever that supports the caliper, but this does not adequately solve the uneven wear of the brake lining.

[0004] From British Patent No. 343437, a drum brake is known, comprising two pairs of brake shoes that always engage simultaneously with the outer and inner surfaces of the drum. Each of both pairs of brake shoes always consists of an inner brake shoe, one end of which is pressed against the inner surface of the drum using a hydraulic piston, and an outer brake shoe, one end of which is pressed against the outer surface of the drum using a second hydraulic piston via a rotatably fastened lever. Both the inner and outer brake shoes of both pairs of brake shoes are rotatably mounted on a second end, meaning that only one of the inner brake shoes and one of the outer brake shoes are always retracted. The brake according to this document is therefore single-acting.

[0005] From U.S. Patent No. 2015083532, an arrangement is known for using ribs on the outer surface of the drum to cool a drum brake having a braking surface on the inside of the drum. This solution cannot be used to engage the drum brake with both the outer and inner cylindrical surfaces of the drum simultaneously. [Overview of the Initiative] [Means for solving the problem]

[0006] Summary of the Invention The double-acting drum brake according to the present invention, which engages simultaneously with the outer and inner surfaces of the drum, has two pairs of brake shoes, each of which always consists of an inner brake shoe with an inner brake shoe lining that is pressed against the inner drum surface during braking, and an outer brake shoe with an outer brake shoe lining that is pressed against the outer drum surface during braking.

[0007] The essence of the present invention is the fact that a set of levers is connected to each of the pairs of brake shoes to press the inner brake shoe against the inner drum and simultaneously pull the outer brake shoe against the outer drum surface, the sets of levers for both pairs of brake shoes being identical and arranged opposite each other in a mirror image, each of the sets of levers being composed of a first class lever whose pivot point is fixedly connected to the stationary part of the braking device, and a second class lever whose pivot point is also fixedly connected to the stationary part of the braking device, the longer arm end of the first class lever being connected to the longer arm end of the second class lever using a sliding pivot hinge.

[0008] One lever of the first class is pivotably connected to the first end of the outer brake shoe using a first outer pin positioned spaced apart from its pivot point in its shorter arm, and pivotably connected to the first end of the inner brake shoe (3) using a first inner pin on the other side of its pivot point where the first outer pin is located.

[0009] One lever of the second class is pivotably connected to the second end of the outer brake shoe using a second outer pin positioned spaced apart from its pivot point in its shorter arm, and pivotably connected to the second end of the inner brake shoe using a second inner pin on the other side of its pivot point where the second outer pin is located.

[0010] One lever of the first class and one lever of the second class are shaped to create space for a brake cylinder between pairs of levers arranged facing each other and mirror-image of each other. To this end, one lever of the first class can be cranked, first toward the inner brake shoe and then toward the inner brake shoe, in the portion between the first inner pin and the end of the longer arm, preferentially in its longer arm. Similarly, one lever of the second class can be cranked, first toward the inner brake shoe and then toward the inner brake shoe, in the portion between the second inner pin and the end of the longer arm, preferentially in its longer arm.

[0011] A brake cylinder fixed and connected to the stationary part of the braking device, having two actuators expandable in opposing directions to extend the action of each of the first class levers of both sets of levers, is located in the space between the sets of levers, which are arranged facing each other and mirror-imaged, and a return spring for pulling the second class levers of both sets of levers together toward each other, is located in the space between the sets of levers, which are arranged facing each other and mirror-imaged, and is always mounted in the space between the second inner pin and the end of the longer arm of the second class lever.

[0012] One advantage of drum brakes with brake shoe linings that engage with both the outer and inner drum surfaces is that, similar to disc brake discs, cutouts can be preferentially made in the cylindrical surface of the drum to promote cooling.

[0013] The brake according to the present invention preferably comprises an outer cover in the shape of an open cylinder, which has inclined blades on its inner cylindrical surface to support the airflow, expelling air from the internal space of the brake during rotation. They thus cool the space and at the same time prevent the intrusion of dust or water that may occur during operation. The effect is increased by bending the edges of the cover inward near a plate, which is bent over the edges of the cover.

[0014] The double-acting drum brake according to the present invention, equipped with brake shoe linings that engage simultaneously with the outer and inner drum surfaces, combines the advantages of drum brakes and disc brakes. At the same time, it eliminates the disadvantages of both. It is protected from moisture as well as dirt and mud. Its effectiveness is comparable to that of disc brakes, regardless of the direction of drum rotation.

[0015] Brief explanation of the drawing The double-acting drum brake according to the present invention is shown in the drawings. [Brief explanation of the drawing]

[0016] [Figure 1] This shows a cross-section of the double-acting drum brake according to the present invention, in a plane parallel to the axis of rotation. [Figure 2] This diagram shows a side view of the double-acting drum brake according to the present invention, with the brake plate removed in the operating position during braking. [Figure 3] This shows a side view of the double-acting drum brake according to the present invention, with the brake plate removed in the release position. [Figure 4] This figure shows an axial view of the brake drum of a double-acting drum brake according to an exemplary embodiment of the present invention. [Figure 5] This figure shows an axial view of the cover of a double-acting drum brake according to an exemplary embodiment of the present invention. [Figure 6] This diagram shows an exploded view of the individual components being mounted together according to an exemplary embodiment of the present invention. [Modes for carrying out the invention]

[0017] Description of Preferred Embodiments of the Invention An exemplary double-acting drum brake, shown in Figure 1 in a cross-section parallel to the axis of rotation of the device to be braked, has a drum 1 in the shape of an open cylinder, the base of which is coaxially fixed to the moving part 7 of the device to be braked. The brake has two pairs of brake shoes, which always engage simultaneously with the outer drum surface 9 and the inner drum surface 10 during braking. Each of both pairs of brake shoes always consists of an inner brake shoe 3, which is pressed against the inner drum surface 10 using an actuator 5 of the hydraulic piston of the brake cylinder 6 via a set of levers 4, 4' during braking, and an outer brake shoe 2, which is simultaneously pulled against the outer drum surface 9 using a set of levers 4, 4'. The inner brake shoe 3 carries an inner brake shoe lining 13, and the outer brake shoe 2 carries an outer brake shoe lining 12.

[0018] The brake cylinder 6 is screwed to a backing plate 8 which is fixed on the stabilizing part of the device to be braked. The shaft 11 passes through the backing plate 8 and rotates to support the movable part 7 of the device, to which the drum 1 is fixedly connected, and the braking unit can be installed on top of it by screwing it to, for example, an automobile wheel using screws 25, according to an exemplary embodiment.

[0019] The sets of levers 4 and 4' for each pair of braking shoes are mounted on the back plate 8, as shown in Figures 2 and 3.

[0020] Each pair of brake shoe lever sets 4, 4' is placed radially toward the drum 1 on the side surface of the back plate 8 between the shaft 11 and the inner brake shoe 3 of each pair of brake shoes. The lever sets 4, 4' consist of one lever 14 of the first class, the pivot point 15 of one lever of the first class being fixedly connected to the back plate 8, and one lever 16 of the second class, the pivot point 17 of one lever of the second class being fixedly connected to the back plate 8 at a distance from the pivot point 15 of one lever of the first class. This distance is smaller than the distance between the opposing ends of the outer brake shoe 2 and larger than the distance between the opposing ends of the inner brake shoe 3.

[0021] One lever 14 of the first class is pivotally connected to the first end of the outer brake shoe 2 using a first outer pin 18 placed at a distance from the pivot point 15 of one lever of the first class in its shorter arm. One lever 14 of the first class has a first inner pin 19 in its longer arm, on the opposite side of the first outer pin 18 from the pivot point 15 of one lever of the first class but at the same distance from the pivot point 15, and uses it to be pivotally connected to the first end of the inner brake shoe 3. One lever 14 of the first class is bent twice in a crank shape in the portion of its longer arm from the first inner pin 19 to the end of the longer arm. This method first bends in a crank shape toward the inner brake shoe 3 and then, in the direction from the inner brake shoe 3, in this exemplary embodiment, in a crank shape in a direction generally parallel to its shorter arm.

[0022] One lever 16 of the second class is pivotally connected to the second end of the outer brake shoe 2 using a second outer pin 20 spaced from the pivot point 17 of one lever of the second class at its shorter arm. One lever 16 of the second class has a second inner pin 21 at its longer arm, on the opposite side of the second outer pin 20 from the pivot point 17 of one lever of the second class but at the same distance from the pivot point 17, and uses it to be pivotally connected to the second end of the inner brake shoe 3. One lever 16 of the second class is bent twice in a crank shape in the portion from the second inner pin 21 to the end of the longer arm in its longer arm. This method is first bent in a crank shape towards the inner brake shoe 3 and then bent in a crank shape in the direction from the inner brake shoe 3, in this exemplary embodiment, in a direction generally parallel to its shorter arm.

[0023] One lever 14 of the first class is connected to the end of the longer arm of one lever 16 of the second class using a sliding pivot hinge at the end of its longer arm. The sliding pivot hinge according to the exemplary embodiment is composed of a nail 22 at the end of the longer arm of one lever 14 of the first class, and the nail 22 is engaged in an elongated opening 23 at the end of the longer arm of one lever 16 of the second class.

[0024] For the pair of brake shoes shown at the top of Figure 2, and for each of Figure 3, there is a set of levers 4 described above for the pair of brake shoes, as shown in Figure 2 and for each of Figure 3, as shown in Figure 3, and for the pair of brake shoes shown at the bottom of Figure 2, there is a set of levers 4' that is mirror-symmetric to the pair of brake shoes shown in Figure 2 and for each of Figure 3, as shown in Figure 3, but both sets of levers 4, 4' together form an expansion mechanism. Both sets of levers 4, 4' are made up of the same parts and are indicated by the same reference numerals. A brake cylinder 6 is placed in the space created by the mirror-opposed cranks of one lever 14 of the first class, which are positioned mirror images of both levers, in the set of levers 4, 4', which are screwed to the back plate 8. The brake cylinder 6 has two actuators 5 that can extend in opposite directions and always act on one lever 14 of the first class, in place between the crank of one lever 14 of the first class and a sliding pivot hinge that connects the end of one lever 14 of the first class to the end of one lever 16 of the second class. A return spring 24 is placed in the space created by the mirror-opposed cranks of the second class lever 16 of pair 4, 4', which are positioned mirror images of both levers, and which constantly acts on the second class lever 16 in place between the crank of the second class lever 16 and the sliding pivot hinge that connects the end of the second class lever 16 to the end of the first class lever 14.

[0025] The function of the double-acting brake according to the present invention is evident from a comparison of Figure 2, which shows a side view and the drum brake according to the present invention in the working position, and Figure 3, which shows a side view and the drum brake according to the present invention in the released position, i.e., the non-braking position.

[0026] In the working position shown in Figure 2, the hydraulic brake cylinder 6 acts via an actuator 5 extended to the longer arm of each of the first class levers 14 in pairs 4, 4', where both levers are positioned mirror images of each other, thereby causing the first class lever 14 to press the first inner pin 19 and the inner brake shoe 3 connected thereto against the inner drum surface 10, while simultaneously pulling the first outer pin 18 and the outer brake shoe 2 connected thereto against the outer drum surface 9. The first class lever 14 also acts via a pin 22 at the end of its longer arm, simultaneously acting on the longer arm of the second class lever 16 through an elongated opening 23 at the end of the longer arm of the second class lever 16, which simultaneously presses the second inner pin 21 and the inner brake shoe 3 connected thereto against the inner drum surface 10, while simultaneously pulling the second outer pin 20 and the outer brake shoe 2 connected thereto against the outer drum surface 9. Therefore, the outer brake shoe 2 and the inner brake shoe 3 are always leading parts regardless of the rotation direction of the drum 1, and thus the brake according to this specification is a double-acting type.

[0027] In the release position shown in Figure 3, the brake cylinder 6 is unpressurized and the actuator 5 is retracted. The return spring 24 acts on the longer arm of each of the second class levers 16 of pairs 4, 4', where both levers are positioned mirror images of each other, thereby causing the second class lever 16 to pull the second inner pin 21 and the inner brake shoe 3 connected thereto away from the inner drum surface 10, which simultaneously presses the second outer pin 20 and the outer brake shoe 2 connected thereto against the outer drum surface 9. In the opposite manner to the braking mode, the second class lever 16 uses the end of its longer arm on the end of the longer arm of the first class lever 14, which pulls the first inner pin 19 and the inner brake shoe 3 connected thereto away from the inner drum surface 10, and simultaneously presses the first outer pin 18 and the outer brake shoe 2 connected thereto against the outer drum surface 9.

[0028] As shown in Figure 4, the cylindrical surface of the drum 1 is cut open by a notch 26 that provides cooling in an exemplary embodiment.

[0029] Simultaneously, the entire device is protected from dust by an outer cover 27 in the shape of an open cylinder, which is an inner cylindrical surface with inclined blades 28, as shown in Figure 5. The inclined blades 28 expel air from the inner space of the brake during rotation, thereby cooling this space and simultaneously preventing dust or water from penetrating during operation. Protection against dust intrusion is increased by bending the edges of the cover 27 inward and the plate 8 outward, as shown in Figure 1.

[0030] Figure 6, an exploded view, shows the relative configurations of the individual components of a brake device according to an exemplary embodiment of the present invention. [Explanation of symbols]

[0031] List of reference characters 1 Drum 2. Outer brake shoe 3. Inner brake shoe 4, 4' Lever set 5 Actuators 6 Brake Cylinder 7. Mobile section 8 Backing 9. Outer drum surface 10 Inner drum surface 11 shafts 12. Outer brake shoe lining 13. Inner brake shoe lining 14. One lever of the first class 15. Pivot point of one lever of the first class 16. One lever of the second class 17. Pivot point of one lever of the second class 18. First outer pin 19 First inner pin 20 Second outer pin 21 Second inner pin 22 nails 23. Long, narrow opening 24. Return spring 25 screws 26 cuts 27 Cover 28 Inclined blade

Claims

1. A double-acting drum brake comprising two pairs of brake shoes, each having brake shoe linings that engage simultaneously with the outer and inner surfaces of the drum (1), wherein each pair of brake shoes always consists of an inner brake shoe (3) with an inner brake shoe lining (13) adapted to engage with the inner drum surface (10), and an outer brake shoe (2) with an outer brake shoe lining (12) adapted to engage with the outer drum surface (9). For each of the pairs of brake shoes, a set of levers (4, 4') is connected to press the inner brake shoe (3) against the inner drum surface (10) and simultaneously pull the outer brake shoe (2) against the outer drum surface (9), and the sets of levers (4, 4') for both pairs of brake shoes are identical and are arranged mirror-like opposite each other. Each of the two sets of levers (4, 4') consists of a lever (14) of the first class, the pivot point (15) of which is fixedly connected to the stationary part of the braking device, and a lever (16) of the second class, the pivot point (17) of which is also fixedly connected to the stationary part of the braking device, the end of the longer arm of the lever (14) of the first class is connected to the end of the longer arm of the lever (16) of the second class using a sliding pivot hinge. One lever (14) of the first class is pivotably connected to the first end of the outer brake shoe (2) using a first outer pin (18) positioned at a distance from the pivot point (15) of the lever of the first class in its shorter arm, and is pivotably connected to the first end of the inner brake shoe (3) using a first inner pin (19) on the opposite side of the pivot point (15) of the lever of the first class, i.e., the opposite side of the first outer pin (18), One lever (16) of the second class is pivotably connected to the second end of the outer brake shoe (2) using a second outer pin (20) positioned at a distance from the pivot point (17) of the lever of the second class in its shorter arm, and is pivotably connected to the other end of the inner brake shoe (3) using a second inner pin (21) on the opposite side of the pivot point (17) of the lever of the second class, i.e., on the opposite side of the second outer pin (20), In the space between the mirror-like pairs of levers (4, 4'), the brake cylinder (6) is fixedly connected to the stationary part of the braking device, having two actuators (5) that are expandable in opposing directions to always act on and expand each of the first class levers (14) of both pairs of levers (4, 4') at a predetermined position between the first inner pin (19) and the end of the longer arm of one of the first class levers (14) of the first class lever (14). A double-acting drum brake with brake shoe lining that engages simultaneously the outer and inner surfaces of a drum, characterized in that a return spring (24) is positioned in the space between pairs of levers (4, 4') that are mirror-like to each other, and is always mounted in a predetermined position between the second inner pin (20) and the end of the longer arm of the second first class lever (16) of both pairs of levers (4, 4') to pull the second class lever (16) of the second class lever (16) toward each other.

2. A double-acting drum brake with a brake shoe lining that engages simultaneously with the outer and inner surfaces of a drum, characterized in that one lever (14) of the first class is crank-shaped in the portion of its longer arm between the first inner pin (19) and the end of the longer arm, first toward the inner brake shoe (3) and then toward the inner brake shoe (3), and one lever (16) of the second class is crank-shaped in the portion of its longer arm between the second inner pin (21) and the end of the longer arm, first toward the inner brake shoe (3) and then toward the inner brake shoe (3).

3. A double-acting drum brake comprising a brake shoe lining that engages simultaneously with the outer and inner surfaces of the drum according to claim 1 or 2, characterized in that the drum (1) is cut open by a notch (26) to support cooling.

4. The drum brake is a double-acting drum brake with a brake shoe lining that engages simultaneously with the outer and inner surfaces of the drum according to claim 1, 2, or 3, characterized in that the drum brake comprises an outer cover (27) in the shape of an open cylinder, which has inclined blades (28) on its inner cylindrical surface to support the airflow.

5. A double-acting drum brake with a brake shoe lining that engages simultaneously with the outer and inner surfaces of the drum, characterized in that the edge of the cover (27) adjacent to the plate (8) is bent inward, and the plate (8) is bent outward and overlaps with the cover (27).

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