South African Inventions Development Corporation

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South African Inventions Development Corporation of Administration

Herbert Scheffel

Rowlen E Von Gericke

Klaus Riessberger

Harry M Tournay

Joseph A Viviers

The invention concerns an inter-axle shear stiffening apparatus for a self-steering rail bogie and a self-steering rail bogie equipped with such apparatus. The apparatus has axle structures including axles ( ) which are journalled in axle box bearings ( ). Radial arms ( ) are connected rigidly to respective axle structures of the bogie an extend towards one another in a fore and aft direction. A lateral force transmitting device ( ) acts between the arms to transmit lateral forces between them while accommodating relative lateral movement between them. The design of this device is such that, irrespective of the extent of relative movement between the arms, the device can only transmit between them lateral forces of limited, predetermined magnitude. This value is chosen such that the bogie is provided with sufficient inter-axle shear stiffness to enhance its hunting stability without excessive force couples being applied to the axle box bearings.

Self-steering bogies

A railway vehicle has a frame which is suspended on wheelsets each having a live axle. The ends of the axles are mounted in axleboxes. Couplings are provided which are attached to the vehicle frame and which couple an axlebox of one wheelset to an axlebox of another wheelset. The couplings are such as to constrain relative movements between the wheelsets in a lateral plane. In addition, each coupling includes a crank lever which operates to uncouple lateral movements of the frame from the movements of the wheelsets, thereby providing a shear stiffness to the vehicle and reducing vehicle hunting at speed. The crank levers are connected to the wheelboxes by links which are inclined with respect to a longitudinal axis of the frame, such that the links lie on axes which intersect at the longitudinal axis.

Railway vehicle suspensions

A railway vehicle has a frame which is suspended on wheelsets (10) each having a live axle (11). The ends of the axles (11) are mounted in axleboxes (12). Couplings (17 to 21) are provided which are attached to the vehicle frame (13) and which couple an axlebox (12) of one wheelset to an axlebox (12) of another wheelset. The couplings are such as to constrain relative movements between the wheelsets (10) in a lateral plane. In addition, each coupling includes a crank lever (19) which operates to uncouple lateral movements of the frame (13) from the movements of the wheelsets (10), thereby providing shear stiffness to the vehicle and reducing vehicle hunting at speed.

A railway bogie or a vehicle is so suspended to axleboxes on a plurality of wheelsets that each wheelset can yaw about a center of yaw, move laterally and move vertically relatively to the frame of the bogie or vehicle. Each axle box has a pair of radially opposed arms extending vertically and links extend from the arms in opposed directions laterally to the plane containing the axis of the axle. The links are ball jointed to the arms and also at their other ends. One link is connected to the link on the other side of the frame via a mechanism transmitting motion across the frame. Such a mechanism may involve a beam pivoted to the frame, bell cranks connected by struts, a torsion bar with arms projecting from it or hydraulic conduits between links which are hydraulic piston and cylinders. The mechanism may be repeated on the other side or the links on that side may simply be jointed to the frame. The purpose of the mechanism is to inhibit longitudinal movement of the center of yaw of each wheelset.

Railway vehicle suspension

A railway bogie is disclosed with wheels of high effective conicity and supported on the wheels through pads with low yaw constraint so that they are self-steering. Cross-members connecting diagonally opposed wheels interconnect yawing movements of the wheelset in opposite senses to counteract the tendency to hunt. Wheels on the same side of the bogie are connected by links pivoted on a lever pivoted on the bogie frame at one end and on the bearings of the wheelsets at the other end. This interconnection inhibits the bogies frame from moving longitudinally when braking or traction forces are present and ensures that yawing movements of the frame are effectively transmitted through the wheelsets and then to the wheel/rail contact area.

Stabilized railway vehicle

A railway truck with a load-bearing structure resiliently supported on two live-axle, self-steering wheelsets, axle bearings being provided on the wheelsets and damping elements being connected longitudinally between axle bearings on the same side of the longitudinal axis of the truck. The damping elements change length with constantly applied forces and transmit rapidly changing forces between the wheelsets with the attenuation of energy. Thus, the damping elements do not interfere with the self-steering ability of the wheelsets and act to counteract wheelset hunting. The wheelsets may be connected to couple any yawing movement of each wheelset in opposite sense to the other wheelset.

Self-steering damping railway truck

A profiled wheel tread for use with self-steering wheelsets, the tread having a running surface, a wheel flange, a taping line passing through the running surface, and a running zone between the taping line and the wheel flange. The invention provides that the effective conicity across the running zone being the rate of increase of rolling diameter decreases from the taping line towards the wheel flange. In another form the effective conicity initially increases from the taping line, reaches a maximum at a lateral deflection of between 1.5 and 4 mm, and then decreases towards the wheel flange. The wheel flange is thinner than normal to increase the gauge clearance. Improvements are thereby obtained in wheel tread wear and rail wear by minimizing creep forces; in hunting stability, because the effective conicity at maximum lateral deflection is low; and in steering ability, because of a high average conicity and increased gauge clearance.

Railway wheel tread profile

A railway truck suspension including a load-bearing member, a pair of wheelsets supporting the load-bearing member, each wheelset being self-steering, and means interconnecting the wheelsets such that they yaw in opposite sense, the interconnecting means comprising a pair of arms on each side of the longitudinal axis of the truck in its direction of travel, each arm being secured at one end to an axle-supported bearing on a wheelset to transmit moments to that wheelset and the arms on the same side of the longitudinal axis extending generally towards each other, and means coupling the other ends of the arms together to allow lost motion between these ends while transmitting rotation of either arm to the other arm.

Self-steering railway truck

A load-carrying railway truck having a longitudinal axis in its direction of travel and including at least one load-bearing member for supporting a load; a pair of live wheelsets supporting the load-bearing member, each wheelset being so mounted in the truck and having such a profile that it is substantially self-steering; means interconnecting the wheelsets to transmit yawing and lateral movements of either wheelset in the opposite sense to the other wheelset; and elastic elements suspending the load to the wheelsets, at least some of the elastic elements having a lateral stiffness in a direction transverse to the longitudinal axis of the truck which is lower than the stiffness provided by them in a direction parallel to the longitudinal axis.

Self steering railway truck

A damping suspension for a railway truck having load-bearing members supported on at least two live wheelsets which are self-steering and which are directly interconnected to couple their yawing movements in opposite senses. The wheelsets are self-steering in that they each have profiled treads of high effective conicity and each is suspended by resilient elements having a low elastic yaw constraint to the load-bearing members. The yaw constraints imposed by the resilient elements are lower than the steering forces generated on the wheelsets on curved track as a result of the tread profile. The coupling between the wheelsets takes the form of diagonally connected resilient members for ensuring that the wheelsets do not oscillate in phase with the load-bearing members to thereby damp any hunting oscillations that may tend to occur.

Damping railway vehicle suspension

A railway truck having at least one load-bearing member supported on two live axle wheelsets and including symmetrical suspension structure for damping hunting of the truck and wheelsets, the structure for each wheelset connected to bearings on the wheelset and two rods pivotally connected at each of its ends to the sub-frames for diagonally interconnecting the wheelsets to couple the yawing and lateral movements of the wheelsets. The sub-frame may be rigid to transmit moments to the wheelset or it may be a pinned structure. The suspension is said to cause inefficient gearing between the wheelsets.

Growing community of inventors

Pretoria, South Africa

Herbert Scheffel