National Research Development Corporation

Gerald M Jones

Dennis H Sansome

Basily B Basily

A ring-shaped device for interposing between two bodies, to measure the force tending to urge them together or pull them apart in a direction coaxial with the ring. Both axial ends of the ring are robust and resist distortion, but between its ends the ring is of convoluted section so that when the ring shortens or lengthens axially under the applied load, hoop stresses are set up in the convoluted part. These stresses are detected by strain gauges located at intervals around the circumference of that part of the ring. The ring may be contained within a protective cylindrical casing, so designed as not to prevent the full magnitude of the applied load being communicated to the ring inside. To improve linearity of the correlation between the applied load and the response of the strain gauges, a stiffening ring may be attached coaxially to the ring; this sleeve may have robust axial ends, and a thinner cylindrical center part registering with the convoluted part of the ring.

Load measuring devices

A variable-geometry plug for use in the plug drawing of tube or other elongated hollow stock. The plug comprises first and second coaxial and relatively-movable parts which co-operate with a deformable annular sealing ring. With the two parts so disposed that the ring is relaxed, the plug can be inserted easily into the undrawn stock. In use, the two parts are caused to move relative to each other, so deforming the ring that it seals an annular clearance between the plug and the undrawn stock. If lubricant is then provided at the upstream face of the seal, the movement of the stock over the seal then tends to draw that lubricant forward across the seal by hydrodynamic action, so tending to fill the clearance with that lubricant at an enhanced pressure. Plugs are described in which this hydrodynamic pressurization is augmented by fluid under pressure supplied direct to the clearance through conduits including passages formed through the body of the plug. Plugs connected to solid bars and flexible leads, and also truly 'floating' plugs no such connection, are described.

Plug drawing of tubes and other hollow items

A variable-geometry plug for use in the plug drawing of tube or other elongated hollow stock. The plug comprises first and second coaxial and relatively-movable parts which co-operate with a deformable annular sealing ring. With the two parts so disposed that the ring is relaxed, the plug can be inserted easily into the undrawn stock. In use, the two parts are caused to move relative to each other, so deforming the ring that is seals an annular clearance between the plug and the undrawn stock. If lubricant is then provided at the upstream face of the seal, the movement of the stock over the seal then tends to draw that lubricant forward across the seal by hydrodynamic action, so tending to fill the clearance with that lubricant at an enhanced pressure. Plugs are described in which this hydrodynamic pressurization is augmented by fluid under pressure supplied direct to the clearance through conduits including passages formed through the body of the plug. Plugs connected to solid bars and flexible leads, and also truly 'floating' plugs no such connection, are described.

A plug for use in the plug drawing of hollow tubes or other stock. A flexible and deformable seal is mounted on the rearward part of the plug. In its relaxed state this seal allows easy insertion of the plug into the stock before drawing begins. In its deformed state, which it is caused to adopt in use, it effectively seals the rearward end of a cylindrical clearance between the plug and the stock, so enabling this clearance to be filled with pressurized lubricant to improve drawing efficiency. The lubricant is supplied through passages formed in the plug and connected to a hollow conduit extending backwards within the undrawn stock. The conduit may be flexible, or may be rigid and then act as a plug bar. The plug may be in two parts which are caused, as drawing begins, to move relative to each other and in so doing to deform the seal.

A joint assembly to make firm but easily releasable contact between two components, for instance a vibration generator of magnetostrictive or piezo-electric type, an an internal plug or mandrel for use in the drawing or draw-bending of metal tube. The assembly comprising first and second ring-shaped members to engage the respective components, and an intermediate member which is fixed to one of the members and in sliding contact with the other so as to define with that other a sealed chamber of variable volume. The chamber is connected in use to a source of pressurized fluid, and when filled with such fluid the chamber is expanded and the two components are urged into firm contact.

Fluid pressurized joint assembly

A load-measuring device, comprising a ring to be interposed between two opposed bodies coaxial with the load axis. Circumferentially-spaced projections separate one axial face of the ring from one of the bodies, and similar but angularly-staggered projections separate the other axial face from the other body, so that when the bodies approach under load the ring is distorted to an undulating shape. The distortion may be measured by a set of strain gauges fixed to the axial faces of the ring, and the output of a second set of gauges fixed to the radial faces of the ring may serve to compensate for distortions of the ring caused by things other than axial thrust, e.g. temperature variation. The projections may be fixed to the ring, or fixed to and located by the ring casing so that they bear against the ring in use.

Growing community of inventors

Trimpley, United Kingdom

Gerald M Jones