Patent GB-1198870-A (GB)
Title: Brake Roller for a Conveyor Track
IPC: F16D57/06
Filed: 1968-07-10
Abstract: 1,198,870. Roller conveyer brakes. HANS VOM STEIN OFFENE HANDELSGESELLSCHAFT. 10 July, 1968 [19 Oct., 1967], No. 32839/68. Heading B8A. [Also in Division F2] A brake roller, for a conveyer track, comprising a roller formed of a closed cylindrical shell and an axle for mounting in the track in a non-rotatable manner, the axle passing centrally, and sealed, through the shell so that the roller can rotate around the axle, and a fluid pump mounted on the axle within the roller, the pump being driven by a cam secured to the shell when the roller turns, the fluid for braking purposes, being pumped alternately from one cylinder chamber into another and back, is characterized in that a piston is mounted slidably but non-rotatably on the axle, the piston having a cam on each end face, further cams being provided at the ends in the cylindrical space formed by the faces of the shell, and a throttle valve, normally elastically held open, in at least one duct formed in the piston, the valve being movable to a greater or less extent toward the closing position in both directions by the flow of the pumped fluid, all the cams having the same rise, and the cams secured to the shell being displaced 180 degrees to one another. As shown, a piston formed of outer and inner sleeves 40, 50, respectively, connected by annular webs 46, 48, is slidable but not rotatable on the fixed axle 10 by reason of ribs 38 cooperating with grooves in the inner sleeve 50. As the shell 18 of the roller is rotated by an article moving on to it, oppositely disposed cams 34, 36, formed as extensions of end covers 16, and engaging aligned cams 42, 44, formed as extensions of the outer piston sleeve 40, drive the piston to and fro. At the top and bottom of the piston, arcuate spaces 52 are provided, each space accommodating two valve bodies 62 provided with tapered ends 70 and joined by a cross-bar 51 with a guide rod 56. The guide rod slides in apertures 60 in the annular webs 46, 48, and the tapered ends 70 co-operate with apertures 66, 68 in the webs 46, 48, acting as valve seats. Springs 52 serve to place the valves, at rest, in an intermediate position. In operation, when the piston is in motion, each valve is forced by the flow of liquid, which fills the whole interior space of the roller, towards the "trailing" valve seat to a greater or less extent depending on the kinetic energy of the article on the roller. Thus the degree of braking action is automatically governed by the weight and speed of the article. Furthermore, after the initial braking phase, the reduced speed of the roller effects a reduction in the speed of liquid flow through the piston, with a consequent reduction in the force on the valves: thus the braking force is progressively reduced. In another embodiment, the space between the webs extends all the way around the inner piston sleeve, and the valve structures shown in Fig. 3, are dispensed with. Instead, a single aperture is provided in web 48 near the top, and a single aperture in web 46 near the bottom. Associated with each aperture is a mushroom valve with its head outside the aperture and its stem and end plate in the piston space. A spring around the valve stem inside the piston space serves to lift the valve head off its seat with the piston at rest. In operation, as the piston moves, the valve head on whichever happens to be the upstream end of the piston is forced to a greater or less extent towards its seat. Annular valves may be used.