Abstract: The invention relates to a drum brake having an electromechanical actuating device. The invention proposes to convert a rotating drive movement of the actuating device by use of a gearwheel and two toothed racks. The toothed racks mesh with the gearwheel on opposite sides thereof and are driven in opposite directions by the gearwheel into translational movements for pressing attached brake shoes against a brake drum. The toothed racks are configured in such a way that the two toothed racks have a common line of action, with resulting symmetrical actuating forces. According to one embodiment of the invention, the lines of action of the toothed racks run tangentially with respect to the gearwheel.

Abstract: A parking brake mechanism in the duo-servo type drum brake includes a link type shoe drive mechanism for expanding a pair of brake shoes and an operating force generator for inputting a shoe operating force into an input lever of the shoe drive mechanism according to the brake operation. The parking brake mechanism also includes a parking brake lever pivotally supported by one brake shoe, wherein a shoe operating force is inputted into the input lever by swing of the parking brake lever, and the brake shoes are expanded via the shoe drive mechanism.

Abstract: Within a wheel cylinder, a drive piston and a control piston, the base ends of which receives a hydraulic pressure from a master cylinder, are oppositely disposed while being axially aligned with each other. A primary shoe is pressed by the drive piston, and an anchor reaction force output from a secondary shoe is distributed to and loaded on an anchor portion and the control piston through a control lever. When the anchor reaction force reaches a predetermined value of force or larger, an anchor-reaction-force control link mechanism operates to move the primary shoe apart from a brake drum, thereby checking the increase of the anchor reaction force.

Abstract: A drum brake assembly has brake shoes 2 and 3 within a rotatable drum 1. The shoes 2 and 3 are displaceable to effect braking by an hydraulic ram 7 and free ends 9 of the shoes react against an abutment 10. This reaction is effected through a layer of viscoelastic damping material and metal plate laminate 110 which may be carried by either the brake shoes or the abutment 10. The viscoelastic layer may be bonded between steel plates and secured by a spring clip to either the brake shoe or the abutment 10. Alternatively the viscoelastic layer may be bonded to the abutment 10. The laminate 110 can be accommodated within a recess in the abutment 10. The provision of the viscoelastic layers through which the brake shoes react on the abutment 10 alleviates the development of noise or squeal during use of the brake assembly.

Abstract: A drum brake comprises two brake shoes (4,5) which are operable hydraulically and/or mechanically. A first brake shoe (4) is supported trailingly in forward travelling direction and leadingly in backward travelling direction. In the forward travelling direction both brake shoes (4,5) are supported trailingly so as to obtain soft response behavior. And a lever (7) is supported at the second brake shoe (5), having one arm pressurized by the piston (2) of the wheel brake cylinder (1), while the other arm (7b) acts directly or indirectly on the first brake shoe (4).

Abstract: This invention relates to a drum brake with two internal expanding brake shoes pivoted at substantially diametrically opposite axes. It incorporates the negative feedback of the brake shoe sliding friction forces to oppose the applied hydraulic brake actuating forces for the purpose of reducing variation in brake torque due to random or uncontrolled variations in the coefficient of friction between brake shoes and brake drum. The required brake shoe friction force feedback is accomplished by eliminating the normally leading brake shoe with its undesirable lock-up prone positive feedback and replacing it with a brake shoe pivoted about an axis diametrically opposite the pivot axis of the normally trailing brake shoe. The location of the shoe pivots is chosen to establish the required feedback magnitude by use of lever ratios whose adequacy is verified by the force equilibrium equations of the brake system.

Abstract: A drum brake or clutch has a fixing member, a drum adapted to be rotatable relative to the fixing member, a pair of arcuate shoes disposed within the drum such as to come in and out of contact with the drum, an actuating device attached to the fixing member and having an actuator adapted to act on at least one end of each of the shoes, and a return spring acting such as to separate each of the shoes from the drum. The drum brake or clutch further includes a lever member pivotally attached to one end portion of each of the shoes. The lever member has one end thereof engaged with the actuator of the actuating device and the other end thereof engaged with an abutment member provided on the fixing member.

Abstract: An improved drum brake is of the type which includes a pair of actuators with a pair of arcuate brake shoes extending therebetween. Each brake shoe is capable of limited movement along a path between the actuation end of one of the actuators and the anchor end of the other of the actuators. The wheel and drum of the drum brake rotate in a normal direction from the actuation end of one actuator to the anchor end of the other actuator so that a leading end of each brake shoe is adjacent the actuator end and a trailing end of each brake is adjacent the anchor end. The improvement includes providing a lining on each of the brake shoes which has a useable layer thereof which is thicker at the trailing end of the brake shoe than at the leading end of the brake shoe. The brake shoe is relatively located on the path toward the actuation end prior to wear of the useable layer and tends to be relocated along the path away from the actuation end during wear of the useable layer throughout use of the drum brake.

Abstract: An internal shoe-drum brake is disclosed in which a pair of arcuate shoes can be applied to a rotatable drum by an hydraulic actuation system for normal service braking when the brake acts as a brake of the "two-leading" shoe type and a mechanical actuation system for parking or emergency braking when the brake acts as a brake of the "duo-servo" type. The hydraulic system comprises two hydraulic pistons, each of which acts on the leading end of a respective shoe, and first and second abutments are provided against which the trailing ends of the shoes are adapted to rest. One abutment is fixed but the other abutment includes an auxiliary hydraulic piston which is adapted to be urged against a fixed stop by hydraulic pressure applied to the pistons. The reaction from the trailing end of a respective shoe tends to urge the piston away from the stop, but the area of the piston is sufficient to prevent this happening when the hydraulic pressure is acting on the piston.

Abstract: A spring-applied, electrically released drum brake which is self-energizing in one direction, and partially deenergizing in the other direction. Regardless of braking direction, the brake shoes are applied with substantially zero force, with the braking force being increased to decelerate and stop the drum within predetermined jerk and deceleration constraints.

Abstract: A strip of label material is fed from a supply roll to a preprint unit which incorporates a set of strip feed rolls driven by an electric motor-reducer drive unit. The drive unit is adapted to be stopped by a rotary solenoid actuated brake controlled by a photocell which senses the advancement of the strip. A print drum is rotatably supported above the generally horizontal path of the strip and has peripherally spaced axially extending rows of printing characters. A set of hammer members are positioned under the print drum and are selectively actuated by a corresponding set of solenoids. The print drum is indexed at a high speed by an electric stepping motor which automatically returns to a start position, and the printing characters are inked by a ribbon which is advanced by another electric motor-reducer drive unit pivotally supported to provide for automatically reversing the feed direction of the ribbon.