A stud for enabling a construction surface to be raised with respect to the ground, said stud comprising at least a first and second element, said first element comprising a first body mounted on a base intended to be placed on said ground, said second element comprising a second body, each of the bodies being provided with a screw thread for mutually engaging one in the other, thus forming an internal body and an external body, said external body being provided with an orifice giving access to the screw thread of the internal body, said stud also comprising a locking member arranged to lock the movement of the first body with respect to the second body in a plurality of positions, the locking member comprising first and second segments, said first segment being designed to pass through said orifice and be inserted between two successive grooves of the screw thread on the internal body, said second segment being designed to pass through said orifice and be interposed in a space provided in an internal wall of the external body.

The present invention relates to a stud for enabling a construction surface to be raised with respect to the ground, said stud comprising at least a first and second element, said first element comprising a first body mounted on a base intended to be placed on said ground, said second element comprising a second body, each of the bodies being provided with a screw thread for mutually engaging one in the other, thus forming an internal body and an external body.

Such studs are known from the American patent application U.S. Pat. No. 5,588,264. The studs described in this patent application comprise two elements each provided with a screw thread for mutually engaging one in the other. The elements form a support for a construction surface. By making one element turn with respect to the other element, the height of the stud is adjustable, which makes it possible to compensate for the difference in height between the construction surface and the ground.

One problem with the known studs is that, after adjustment of the height, the elements may still move with respect to each other, thus falsifying the adjustment. The elements may for example move and lose their adjustment because of vibration incurred during transportation thereof. This has the consequence that the actual height is no longer equal to the height at which the stud was adjusted.

The object of the present invention is to produce a stud that makes it possible, after adjustment, to prevent movement of one element with respect to the other, and this in a simple and reliable fashion.

To this end, a stud according to the invention is characterized in that, said external body being provided with an orifice giving access to the screw thread of the internal body, said stud also comprising a locking member arranged to lock the movement of the first body with respect to the second body in a plurality of positions, the locking member comprising first and second segments, said first segment being designed to pass through said orifice and be inserted between two successive grooves of the screw thread on the internal body, said second segment being designed to pass through said orifice and be interposed in a space provided in an internal wall of the external body. Use of the locking member makes it possible to remedy the fact that the elements move with respect to each other. This is because, owing to the fact that the first segment is inserted between two successive grooves and passes through the orifice, the two elements are locked with respect to each other. Thus the alignment in height is lo maintained. The locking member thus affords maintenance of the adjusted height in a simple and reliable fashion.

Preferably, said space comprises a surface, the thickness of which increases, said second segment being arranged to engage by rotation on this surface after the locking member has been introduced into the orifice. The advantage of this surface is that, in combination with the rotation of the locking member, it helps to convert this rotation into an axial movement of the first segment. Thus the second segment will be pushed in the direction of the internal body and will drive the first segment between two successive grooves of the screw thread.

In the same drawings the same reference has been allocated to the same element or to a similar element.

FIG. 1illustrates an embodiment of a stud according to the invention. This stud comprises a first element1and a second element2. The first element1comprises a first body3mounted on a base4intended to be placed on the ground. The second element2comprises a second body5provided at its top part with a surface6. This surface6serves as a support for pavement elements such as for example slabs or the like. The first body3is provided with a screw thread7applied inside the body3. The second body5is provided with a screw thread8applied outside the body5. The two screw threads7and8are formed so as to be able to mutually engage one in the other, so as to move the first and second bodies with respect to themselves. Thus the second body5forms an internal body5and the first body3forms an external body3of the stud.

The invention is however in no way limited to a stud comprising two elements and also applies to studs comprising intermediate elements provided with a screw thread. Obviously it is possible to provide the first body3with a screw thread applied to the outside and second body5with a screw thread applied to the inside.

The stud also comprises a locking member9. As illustrated inFIG. 2, the locking member comprises a first segment10, a second segment11and an engagement segment12. In the example embodiment the first segment10forms one end of the locking member while the engagement segment12forms the other end. The second segment being situated between the first segment and the engagement segment and extends perpendicular to the axis I of the locking member. The first segment10is designed to be inserted between two successive grooves of the screw thread8on the internal body5. The second segment11is designed to be interposed in a space provided in an internal wall of the external body3as will be described in more detail below. In this embodiment, the engagement segment12is formed by a handle. It is also possible for the engagement segment12to be formed by a female element of a hexagonal member, or any other elements enabling the locking member to be manipulated.

The locking member9can be housed in the base4, as illustrated inFIG. 1, so that the locking member9can be dislodged therein before use. This facilitates the manufacture for molding of a stud according to the invention.

The external body3also comprises an orifice13situated in the wall of this body and passing through the latter. The orifice13gives access to the screw thread8of the internal body5. The orifice13is oriented in the direction of the height of the stud and perpendicular to the screw thread7and8. As illustrated inFIG. 3, level with the orifice, the screw thread is interrupted in order thus to create a space15provided in an internal wall of the external body. This space comprises a surface14. The thickness of this surface14increases from the bottom towards the top. The surface14thus enables the second segment to engage therein, after the locking member9has been introduced into the orifice.

In order to introduce the locking member9into the orifice13, the locking member must be oriented so that the first segment10points in the direction of the body3, and the second segment is oriented towards the base4. By dint of entering the orifice, the first segment10will come to slide between two successive grooves of the screw thread8. When the first and second segments have passed through the orifice13, the locking member9is driven in rotation by a user. Through this rotation, the second segment will come into contact with the surface14. Since this surface increases, the second segment will be pushed in the direction of the internal body and will make the first segment slide more between two successive grooves of the screw thread.

When it is situated between the grooves of the screw thread, the first segment10points in a direction perpendicular with respect to the direction of this screw thread8. The locking member9, after having being gripped against a surface14, remains fixed to the latter. When the locking member9is in the locking position, there is therefore friction between the first segment10and two successive grooves of the screw thread8.

The screw thread8of the internal body5has a trapezoidal thread with a vertex angle α, and the first segment10has the shape of a truncated cone with a vertex angle β. In order to cause optimum friction, the vertex angle α is preferably substantially equal to the vertex angle β. Through this friction, the locking member9locks the movement of the internal body5with respect to the external body3. In this way, the locking member9make it possible to lock the movement of a first element1with respect to a second2adequately.