1. Blind rivet including a deformable sleeve and a divisible mandrel,
the assembly thus formed being positioned and passing through the apertures made substantially coaxial and formed in at least two elements to be assembled,
the sleeve comprising two ends:
a first end comprising a preformed head for defining a first support surface on the external surface of a first element, and
a second end which, under the action of deformation by pulling on the mandrel, comes to define a second support surface on the external surface of the second element,
prolonging the force having the effect of bringing the two support surfaces closer together and consequently bringing closer together the two elements to be assembled, characterised by the fact that the sleeve consists of a single piece, and is preformed in order to have a second end in two parts which, under the action of an axial force, separate by breaking before a sleeve part, set in motion by the pulling force of the mandrel, opens out around the sleeve part that remained stationary, the expansion of the movable part referred to as a collar being done without bending.
2. Rivet according to claim 1, characterised by the fact that the end of the movable sleeve part that comes to open out over the stationary sleeve part is advantageously preformed internally with a conical shape that slides over the stationary part.
3. Rivet according to claim 1, characterised by the fact that the end of the stationary sleeve part over which the movable sleeve part opens out adopts a conical external shape.
4. Rivet according to claim 3, characterised by the fact that the angle formed by the conical surface belonging to the stationary part of the sleeve lies between 14 and 19 degrees.
5. Rivet according to claim 3, characterised by the fact that the angle formed by the conical surface belonging to the stationary part of the sleeve lies between 10 and 19 degrees.
6. Rivet according to claim 2, characterised by the fact that the angle formed by the internal conical surface belonging to the movable part lies between 5 and 10 degrees.
7. Rivet according to claim 1, characterised by the fact that said sleeve is made from an aluminium alloy.
8. Rivet according to claim 1, characterised by the fact that said mandrel is made from a stainless steel.
9. Rivet according to claim 1, characterised by the fact that the mandrel has a mechanical strength lying between 1500 and 2000 MPa.
10. Rivet according to claim 1, characterised by the fact that the mandrel has a mechanical strength lying between 1200 and 2000 MPa.
11. Rivet according to claim 1, characterised by the fact that the end of the collar coming into contact with the head of the mandrel is preformed with a conical surface coming into correspondence with a conical surface made on the head of the mandrel.
12. Rivet according to claim 11, characterised by the fact that the angle of the tapered surfaces, belonging respectively to the collar and the mandrel head and remaining in contact during the riveting, is equal to approximately 25 degrees.
13. Rivet according to claim 9, characterised by the fact that the angle of the tapered surface belonging to the collar is equal to approximately 25 degrees and the angle of the tapered surface belonging to the mandrel and remaining in contact during the riveting with the tapered surface is equal to approximately 18 degrees.
14. Rivet according to claim 1, characterised by the fact that said mandrel is preformed with a plurality of serrations onto which the head of the sleeve is crimped.
15. (canceled)
16. Method of fitting a rivet according to claim 1, characterised in that it includes crimping the head of the sleeve onto the serrations of the mandrel once the movable part of the sleeve is leaning on the element to be fixed and before exceeding of a pulling force corresponding to the maximum limit of resistance to elastic deformation of said movable part once opened out.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for aligning a cutter spindle of a granulator relative to a cutting plate, comprising the steps of:
rotationally driving the cutter spindle with a drive motor,
measuring a force acting on the cutter spindle,
generating a signal in response to the measured force, and
adjusting an alignment of the cutter spindle relative to a cutting plate by operating adjusting means depending on the generated signal, with the adjusting means pivoting the cutter spindle about at least two pivot axes which enclose an angle with each other.
2. The method of claim 1, wherein the alignment is an angular alignment.
3. The method of claim 1, further comprising the steps of:
operating a first adjusting means until the generated signal exceeds a predetermined threshold,
operating the first adjusting means in an opposite direction, until the generated signal falls below a predetermined threshold,
operating a second adjusting means until the generated signal exceeds a predetermined threshold,
operating the second adjusting means in an opposite direction, until the generated signal falls below a predetermined threshold.
4. The method of claim 3, further comprising the steps of:
operating a third adjusting means until the generated signal exceeds a predetermined threshold,
operating the third adjusting means in an opposite direction, until the generated signal falls below a predetermined threshold.
5. The method of claim 1, wherein the cutter spindle is aligned along its longitudinal axis by simultaneous operation of the adjusting means.
6. The method of claim 1, wherein the adjustment of the alignment of the cutter spindle is performed by pivoting the cutter spindle about three pivot axes which enclose an angle with each other.
7. The method of claim 1, wherein the pivot axes are substantially parallel to the cutting plate.
8. The method of claim 1, wherein the pivot axes are located in a plane.
9. The method of claim 1, wherein the force acting upon the cutter spindle is measured by measuring the current drawn by the drive motor or with a load cell.
10. The method of claim 1, wherein the adjusting means are moved in steps, until the signal reaches a threshold indicating contact between the cutter spindle and the cutting plate.
11. The method of claim 1, wherein the alignment is adjusted under program control.
12. The method of claim 1, wherein the alignment is adjusted during operation of the granulator.
13. The method of claim 1, wherein the force acting upon the cutter spindle is measured continuously.
14. The method of claim 1, wherein the granulator is a submerged granulator.
15. A granulator for producing plastic granulate, comprising:
a cutting box,
a cutter spindle,
a cutter holder rotatably disposed in the cutting box and held by the cutter spindle, with the cutter holder cooperating with a cutting plate during operation,
a drive motor connected with the cutter spindle,
means for measuring a force acting upon the cutter spindle,
means for generating a signal corresponding to the force, and
adjusting means for adjusting alignment of the cutter spindle relative to the cutting plate by operating adjusting means depending on the signal, with the adjusting means pivoting the cutter spindle about at least two pivot axes which enclose an angle with each other.
16. The granulator of claim 15, further comprising a bearing housing coupled to the adjusting means.
17. The granulator of claim 15, further comprising a bearing plate coupled to the adjusting means.
18. The granulator of claim 15, comprising three adjusting means arranged in a circumferential direction symmetrically with respect to the cutter spindle.
19. The granulator of claim 15, wherein the adjusting means are controlled with a motor, or hydraulically, or thermally, or pneumatically, or manually.
20. The granulator of claim 15, further comprising a control device for controlling the adjusting means depending on the generated signal.
21. The granulator of claim 15, wherein the means for measuring a force acting upon the cutter spindle is constructed as means for recording a motor current of the drive motor.
22. The granulator of claim 15, wherein the granulator is a submerged granulator.