WO1992015792A1

WO1992015792A1 - Screw element which can be secured against unscrewing

Info

Publication number: WO1992015792A1
Application number: PCT/DE1992/000121
Authority: WO
Inventors: Ralph Müllenberg
Original assignee: Muellenberg Ralph
Priority date: 1991-03-05
Filing date: 1992-02-20
Publication date: 1992-09-17
Also published as: DE4106943C1; CZ158893A3; JPH06501092A; EP0574430A1; CA2105574A1

Abstract

The screw element (100) proposed comprises a body (3) with an internal thread (9) by means of which it can be screwed on to a screw (1). A longitudinal extension (10) to the body (3) has a spiral external surface (17) on which a locking ring (20) with a matching spiral internal surface (27) is disposed. Rotation of the locking ring (20) with respect to the body (3) locks the extension (10) on to the screw (1) by frictional forces, hence preventing the screw element (100) from unscrewing.

Description

^υ ^ ^{, D / yz} PCT / DE92 / 00121

Screw element that can be secured against loosening

For screw elements such as nuts and the like, various configurations for securing against loosening of the tightened screw connection under the axial forces and possibly occurring vibrations are known. The simplest embodiment is the split pin nut, which is bordered in a crenellated manner on one axial side, the depressions between the battlements being able to be covered with a transverse bore of the screw and a split pin being inserted transversely. Disadvantages here are the necessity of making a transverse bore in the screw and, in particular, the fact that the securing against loosening only occurs in certain rotational positions of the screw element, namely when one of the depressions between the crenellations is in the transverse bore the screw covers, is possible. Another method of securing a screw connection against loosening is the attachment of a spring washer. This digs with one cutting edge into the underside of a nut, with the other cutting edge into the counter workpiece and prevents the nut from loosening by the orientation of the cutting edges. When tightening, the surfaces on which the cutting edges of the spring lock engage are damaged. A deliberate loosening of the secured screw connection is only possible against the action of the spring washer and with greater destruction of the attack surfaces thereof. Finally, there are screw elements in the form of so-called locking nuts, which have radial cutting edges on their contact surface in the manner of a file cut, which claw into the mating surface in a similar way as is the case with the spring washer. Naturally, the disadvantages are the same, whereby the notches formed can be the starting point for permanent breaks (magazine "Construction &Electronics" (1991) No. 4 of February 20, 1991, page 4; EP-Bl 290 967)

The invention has for its object to provide a screw element that is secure against unscrewing, in which no special design is required on the screw and the contact surfaces are not damaged by the securing process.

This object is achieved according to the invention by a screw element according to claim 1.

The screw element is tightened in the usual way until the desired tension in the screw connection is reached. The clamping ring is then rotated on the spiral surface, as a result of which the sleeve-like attachment, which of course is of correspondingly thin-walled design, is compressed radially and is fixed on the screw with the internal thread, so that a force-locking jam against loosening on the screw is achieved. Only a relatively slight rotation of the body of the screw element and of the clamping ring relative to one another is required to bring about the jamming.

The actual clamping connection remains unaffected by this process, because the functions of actuating the screw element to achieve the desired axial force in the screw on the one hand and securing against loosening of the screw element are completely separate from one another. The screw element can be tightened without the contact surfaces of securing elements being damaged and without additional moments having to be applied for the actuation or activation of securing means. In addition, due to the radial compression of the bush-like extension provided with the internal thread, the engagement of the thread or its supporting portion increases, so that the local surface pressure can be reduced with the same axial forces of the screw connection.

The use of spiral surfaces to achieve radial jamming is known per se from GB-PS 293 122. There are two rings arranged one above the other, one of which is seated on a shaft with its cylindrical inner circumferential surface, the other lies with its cylindrical outer circumferential surface in a corresponding bore of an outer component. The mutually facing U surfaces of the two rings are spiral in a cross section perpendicular to the axis of the shaft. When the outer component is rotated with respect to the shaft, the two spiral rings on their spiral surface are also rotated relative to one another by the friction conditions, as a result of which the outer component is jammed on the shaft.

In its simplest embodiment, the screw element with body, sleeve-like attachment and clamping ring forms the basic shape of a locking nut which, according to claim 2, is designed on the outer circumference of the body with a design for attacking a turning tool, for example on the circumference of longitudinal grooves or radial bores for attack has a hook wrench or is hexagonal in the usual way.

The clamping ring can also have a corresponding design.

In this way, the body of the screw element and the clamping ring can be effectively rotated against one another with high torque while simultaneously acting on two turning tools in order to produce the clamping effect on the screw.

So that when the body of the screw element and the clamping ring are rotated relative to one another, not too much of the brought torque for the mere compression of the sleeve-like approach In order to overcome the play on the screw, a longitudinal slit according to claim 4 is recommended, which considerably increases the deformability of the sleeve-like attachment in the radial direction, without the stability in the circumferential direction and thus the holding force to significantly reduce the fuse.

In the drawing, an embodiment of the invention is shown.

1 shows a longitudinal section through the axis through a screw element;

Fig. 2 shows a section along the line II-II in Fig. 1st

The screw element designated 100 as a whole in FIGS. 1 and 2 represents a locking nut which can be screwed onto a screw or screw spindle 1 with an axis 2, which is only indicated by dash-dotted lines in FIG. 1. The screw element 100 comprises a body 3 in the form of a thick disk 4, the thickness of which in the exemplary embodiment shown is approximately a quarter of the diameter. The outer circumference 5 of the disk 4 is cylindrical and has four longitudinal grooves 6, which are evenly distributed over the circumference and on which a hook wrench for rotating the screw element 100 can engage.

On the right-hand flat side of the disk 4 in FIG. 1, the body 3 has an elevation 7 that is circular in cross-section with an outer boundary surface 8 that is perpendicular to the axis 2 and that forms the contact surface of the screw element 100 with which the screw element bears against a counter surface on a component against which the screw 1 is to be tightened.

The washer 4 is provided with an internal thread 9 which can be screwed onto the corresponding external thread of the screw 1.

The thread 9 continues through a sleeve-like extension 10 which is coaxial with the axis 2 and which is provided on the flat side of the disc 4 facing away from the elevation 7. The thread 9 thus bears on the screw 1 over the entire length of the body 3 and the shoulder 10. The thread pitch is dimensioned relative to the thickness of the body 3 so that there is space for several threads in the body 3 alone.

In a plane passing through the axis 2, the axial sleeve-like extension 10 has a radially continuous longitudinal slot 11 at one or more locations distributed over the circumference, which facilitates the radial compression of the extension 10.

This radial compression is brought about by a clamping ring 20 which is rotatably arranged on the outer circumference of the axial extension and is not slotted and is provided with a large cross section in comparison to the extension because it has to absorb the ring tensile stresses which give rise to the radial forces.

The axial extension 10 protrudes beyond the clamping ring 20 towards the side remote from the body 3 and has an outer circumferential groove 12 there for receiving a snap ring 13, by means of which the clamping ring, which is loose in the untensioned state, is held on the extension 10 and thus the body 3 remains captively connected.

The outer circumference 15 of the clamping ring 20 is cylindrical in the exemplary embodiment and has longitudinal grooves 16 in places distributed over the circumference, in which a hook wrench can engage in order to turn the clamping ring 20 relative to the body 3.

The clamping arrangement formed by the extension 10 and the clamping ring 20 is explained in detail with reference to FIG. 2. In the sectional view, an imaginary cylindrical surface 14 with the center point on the axis 2 is indicated by dash-dotted lines. The outer circumferential surface 17 of the sleeve-like extension 10 is formed by a spiral surface 18 coaxial with the axis 2, the generatrices of which are parallel to the axis 2. The inner surface 27 of the clamping ring 20th is formed by a same spiral surface 28, which rests on the spiral surface 18 from the outside. The two spiral surfaces 18, 28 lie in the first two quadrants of the cross section of FIG. 2 outside the imaginary cylinder surface 14, intersect the spiral surface 14 in the "six o'clock" position and lie in the last two quadrants within the Cylinder surface 14. The local radius of the spiral surface 18 decreases from a point 19 of the largest radius according to FIG. 2 in a clockwise direction over almost 360 and jumps back to the largest radius at a point 21 of the smallest radius on a transition surface 22. The inner circumferential surface 27 of the clamping ring 20 is designed accordingly, that is, the radius decreases clockwise from a point 19 'of the largest radius to a point 21' of the smallest radius, whereupon the inner circumferential surface 27 in a transition area 22 'in a narrow angular range such as ¬ which jumps back to position 19 'of the largest radius. The amount of the slope of the spiral surfaces 18, 28 in the circumferential direction is selected so that it lies in the self-locking area and, therefore, the tightening ring, once tightened, no longer turns back without external torque. At a radius difference of 2 mm at 50 mm in diameter is obtained in the settlement a wedge with the slope ^■ _ "2: 150, which is less equal than one degree, the Grenzwin¬ angle of self-locking for steel on steel at about 7. In the example, the spiral surfaces 18, 28 are thus far in the self-locking range, which also means that the torque applied to the clamping ring 20 is converted into radial clamping force with a high degree of efficiency.

2, the tensioning arrangement 10, 20 is shown in the not yet fully tensioned state. In the completely untensioned state, the transition surfaces 22, 22 ′ are even more adjacent to one another in the circumferential direction. The function of the bracing can be illustrated by the Point 19 of the sleeve-like extension 10 is considered, which has the largest radius of the spiral surface 18. When this point is moved clockwise with the clamping ring 20 held in accordance with FIG. 2, it lies one after the other at points on the spiral surface 28 which have an ever smaller radius. As a result, point 19 is pressed radially inward. The same applies to all other places in the beginning, with the exception of the zones that remain free between places 19 and 21 '. In this way, the axial extension 10 is evenly compressed radially and clamped non-positively on the screw 1. As a result, the screw element 100 can no longer be rotated and maintains its rotational position once it has been reached.

The radius difference of the locations 19, 21 can be approximately 2 mm for a diameter of the screw 1 of 30 to 50 mm, as in the example already mentioned. By rotating the clamping ring 20 in a clockwise direction of 36 relative to the sleeve-like attachment 10, a radius tolerance of 0.2 mm can be bridged, which is sufficient in most cases. The tightening turning strokes in question will in no case have to be exceeded 45. The transition surface 22 'would be located at the position 22 "indicated by the dashed line in FIG. 2 with the clamping ring 20 rotated accordingly with respect to the axial extension 10.

In operation, the screw element forming a locking nut can be tightened by rotating the body 3 until the boundary surface 8 rests on a counter surface. A torque which causes the tension in the screw 1 is then applied to the body 3, for example with the aid of a hook wrench which engages in the grooves 6. With this tightening, no additional moments have to be applied to secure the screw element 100, ie the entire torque applied to the circumference 5 benefits the tensioning of the screw 1. When the tensioning is achieved, the tensioning ring 20 is rotated using a similar tool which engages in the grooves 16 of the tensioning ring 20. As a result, the sleeve-like extension 10 is radially compressed and clamped on the screw 1 in the manner described. If necessary, this tension can be held against the body 3 with another turning tool so as not to change the tension achieved for the screw 1.

The screw element 100 is secured entirely within this element without an attack on the component forming the counter bearing for the boundary surface 8 or on the screw 1 and without the fuse depending on the material of this counter surface.

The available length of the thread 9 is increased by the sleeve-like extension 10, and the engagement of the screw thread is also improved by the radial compression in the area of the axial extension 10.

The body 3 does not have to be a pure mother, as in the exemplary embodiment shown, but can itself also be a component that performs another function. Also in the example, only one extension 10 with a clamping ring 20 is provided on one side, although a double-sided version and a version with two or more clamping rings on one side are also possible.

Claims

Patent claims

1. Screw element (100) which can be secured against loosening and has a disk-shaped body (3), with a continuous internal thread (9) in the body (3), of which several threads in the body (3) have space, with one to the internal thread ( 9). Concentric sleeve-like attachment (10) provided on at least one side of the body (3), through which the internal thread (9) continues, with a spiral surface (18) which is on the outer peripheral surface (17) of the sleeve-like attachment ( 10) is arranged coaxially to the axis (2) of the internal thread (9) and is formed from generatrices parallel to the axis (2) and has a slope in the circumferential direction in the self-locking area, and with at least one arranged on the spiral surface (18), Rotatable clamping ring (20) which is undivided in the circumferential direction, the inner circumferential surface (27) of which is a spiral surface (28) corresponding to the spiral surface (18) of the projection (10) and resting thereon, so that when the clamping ring (20) is rotated, the projection (10) can be compressed radially and the screw element can be clamped on an external thread part (1) screwed into the internal thread (9).

2. Screwing element according to claim 1, characterized gekenn¬ characterized in that the screwing element (100) is formed as a nut with an on the outer circumference (5) of the body (3) provided design (6) for the attack of a turning tool.

3. Screw element according to claim 1 or 2, characterized in that the clamping ring (20) on the outer circumference (15) has a design (16) for the attack of a turning tool.

4. Screw element according to one of claims 1 to 3, characterized in that the body (3) is longitudinally slid at least in a longitudinal region of the sleeve-like extension (10) in a plane passing through the axis (2).