AU2013339553B2

AU2013339553B2 - Screw connection arrangement

Info

Publication number: AU2013339553B2
Application number: AU2013339553A
Authority: AU
Inventors: Michael MERGNER; Detlef Papajewski; Peter Schatz; Piotr SZCZELINA
Original assignee: FLSmidth AS
Current assignee: FLSmidth AS
Priority date: 2012-10-29
Filing date: 2013-10-28
Publication date: 2016-12-01
Anticipated expiration: 2033-10-28
Also published as: PE20151304A1; DE102012110338A1; CN104884820A; DK2912324T3; EP2912324B1; EP2912324A1; WO2014067900A1; AU2013339553A1; BR112015009534A2; CL2015001074A1; BR112015009534B1

Abstract

The invention relates to a screw connection arrangement comprising a sleeve (3) and a pin (4). Said sleeve (3) comprises, on a first sleeve end, a radially protruding collar (5) and a first sleeve longitudinal section (6) which starts from the first sleeve end, the first sleeve longitudinal section (6) can be widened by longitudinal slots (7) and has a conically tapering inner diameter starting from the first sleeve end. The pin (4) comprising a first pin longitudinal section (12) is inserted into the sleeve longitudinal section (6) The pin (4) comprises, on a second end, a second pin longitudinal section (13) having a thread and protruding out, at least partially, from the sleeve (3), the first pin longitudinal section (12) conically tapering in the direction of the second end of the pin (4).

Description

-1 - 2013339553 07 Oct 2016

SCREW CONNECTION ARRANGEMENT

Description [0001 ] The invention relates to a screw connection arrangement by way of which two parts can be connected together. The screw connection arrangement is intended to be suitable in particular for screw connections which are formed in a conventional manner with screws and nuts.

[0002] A screw connection having a screw and nut is a conventional, very widespread connection form. The parts to be connected together have fastening openings which are positioned one over the other, wherein the parts are then connected together by plugging the screw into the fastening openings and tightening the nut. In particular, the two parts can be provided with a flange into which the fastening openings have been introduced.

[0003] In the case of conventional screws having nuts, a form-fitting connection is produced in the longitudinal direction in that the screw head bears on one side and the nut on the other side against outer surfaces of the parts. At the point where the two parts rest directly against one another, a friction fit is achieved in the transverse direction by the tightening of the screw and nut. A clearance-free form fit in the transverse direction is not possible because the fastening openings have to have an oversize with respect to the screw in order that the screw can be introduced easily.

[0004] Specifically in machines that operate under harsh use conditions, for example in conveying machines, consideration should be given to the fact that the inside diameter of the fastening openings can also be reduced by dirt, wherein specifically heavy parts that are to be connected together can be positioned with a perfect fit manner only with difficulty.

[0005] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0006] At least one preferred embodiment of the present invention advantageously specifies a screw connection arrangement which is easy to handle and allows improved strength and accuracy of a screw connection.

[0007] The present invention teaches a screw connection arrangement according to claim 1, which has a sleeve and a bolt. - 2 - 2013339553 07 Oct 2016 [0008] The sleeve has a radially protruding collar at a first sleeve end and a first longitudinal sleeve section starting from the first sleeve end, wherein the first longitudinal sleeve section is able to be spread open by way of longitudinal slits and has a conically narrowing inside diameter starting from the first sleeve end.

[0009] As a further constituent part of the screw connection arrangement according to the invention, the bolt has been inserted into the first longitudinal sleeve section with a first longitudinal bolt section and has, at a second end of the bolt, a second longitudinal bolt section with a thread onto which a bolt nut has been fitted, said second longitudinal bolt section extending at least partially out of the sleeve, wherein the first longitudinal bolt section narrows conically in the direction of the second end of the bolt.

[0010] Initially, the radially protruding collar of the sleeve allows the screw connection arrangement to be braced in a longitudinal direction in order to connect two parts. However, according to the invention, the first longitudinal sleeve section is also radially expanded when the first longitudinal bolt section is drawn more deeply with its conical shape into the likewise conically narrowing first longitudinal sleeve section by tightening of a bolt nut fitted on the thread of the second longitudinal bolt section. As a result of the radial expansion of the first longitudinal sleeve section, said radial expansion taking place only after insertion, it is possible for the sleeve to be initially pushed into the mutually assigned fastening openings of two parts without jamming during assembly, even when said fastening openings are not oriented precisely with respect to one another. When the first longitudinal sleeve section is spread open by the first longitudinal bolt section, a lateral surface, interrupted by the longitudinal slits, of the first longitudinal sleeve section can then be expanded to such an extent that said lateral surface bears at least sectionally against an internal circumference of the fastening opening of the first part and that of the second part. The radial gap, initially necessary for the insertion of the sleeve, between the sleeve and the internal circumference of the fastening openings is closed as a result, and so a clearance-free form-fitting connection is also achieved in the transverse direction.

[0011] As a result of the first longitudinal sleeve section being spread open, in the event of a slight misalignment of the two parts, it is also possible for the mutually assigned fastening openings to be centered and thus also for the parts to be connected together to be oriented precisely. According to the invention, a more accurate screw connection which is particularly easy to handle can thus be achieved. -3- 2013339553 07 Oct 2016 [0012] When the lateral surface of the first longitudinal sleeve section bears in a clearance-free manner in the radial direction against the internal circumference of the fastening openings, a clearance-free form fit is achieved, as seen in the transverse direction, in addition to the friction fit between the two parts. On the other hand, as seen in the longitudinal direction of the screw connection arrangement, the form fit that is also conventional in the case of a screw is supported by a friction fit such that, compared with a conventional screw connection, increased strength of the screw connection can be achieved both in the axial direction and in the transverse direction.

[0013] According to a particularly preferred configuration of the invention, provision is made for an external thread for receiving a sleeve nut to be provided on a second longitudinal sleeve section, starting from a second sleeve end, wherein an end face at the second sleeve end forms an abutment face for the bolt nut. According to this particularly preferred configuration of the invention, the screw connection arrangement is braced by way of two different elements, specifically the bolt nut and the sleeve nut.

[0014] The functioning of the sleeve with the sleeve nut corresponds substantially to a conventional screw and a conventional nut in this case. On the other hand, the bolt nut serves to draw the bolt more deeply into the sleeve, that is to say in the direction of the second sleeve end, in order to spread open the first longitudinal sleeve section radially and thus to allow radial bracing.

[0015] The sleeve nut and bolt nut can be tightened in different ways. Depending on the application, however, it may be disadvantageous if the sleeve nut is initially tightened to a very great extent, because then the parts to be connected together are also connected so tightly in the transverse direction by a friction fit that tightening of the bolt nut cannot center the mutually assigned fastening openings as a result of the first longitudinal sleeve section being spread open.

[0016] A similar problem can arise when, in a configuration having a bolt nut and a sleeve nut, the bolt nut is initially tightened to a very great extent. In such a case, although optimal centering of the two fastening openings is achieved, the lateral surface of the first longitudinal sleeve section then jams firmly against the inner circumference of the fastening openings. This frictional connection, which is desired per se and acts in the longitudinal direction, can, however, result in it not being possible to brace the sleeve in the longitudinal direction, or only with a very large application of force, by way of the sleeve nut. -4- 2013339553 07 Oct 2016 [0017] In order to avoid the described problems, it may be expedient to alternately tighten the sleeve nut and the bolt nut in a number of steps. Alternatively, it is also possible to initially firmly tighten the bolt nut in order to achieve precise centering of the fastening openings, wherein, before the sleeve nut is tightened, the bolt nut is loosened at least a little and only subsequently firmly retightened.

[0018] In order, when the sleeve nut and the bolt nut are tightened, to avoid co-rotation of the sleeve and of the bolt, respectively, provision should be made of a corresponding fastening means. With regard to the sleeve, the collar can have tool receiving surfaces, for example a hexagon, on its outer circumference such that the sleeve can then be held by a corresponding tool during assembly. In a corresponding manner, the bolt can also have a tool receptacle at its first and/or second end in order to allow counter-bracing. It is possible to provide a slit or a hexagon socket both at the first end and at the second end, in order to be able to engage an appropriate tool there. At the first end of the bolt, provision can also be made for the first longitudinal bolt section to extend out of the sleeve, wherein a hexagonal protuberance or the like can be provided there, too. At the second end of the bolt, care should be taken to ensure that the tool receptacle does not extend beyond the thread which is provided there and is expediently configured as an external thread.

[0019] In addition to corresponding tool receptacles, a rotation lock can also be achieved by way of a form fit. Thus, it is for example possible for the sleeve not to be exactly in the form of a circular cylinder around the entire circumference and along the entire length of its outer side, wherein at least one of the two parts to be connected together then has a complementary contour that deviates from a circular shape. Furthermore, it is also possible to form a form-fitting rotation lock between the conically narrowing first longitudinal bolt section and the associated first longitudinal sleeve section. Such a rotation lock can be provided for example in that one of the elements is provided with a protrusion or with a fin extending in the longitudinal direction, said protrusion or fin engaging in a groove or a slit in the other element. In particular, at least one of the slits on the first longitudinal sleeve section that are necessary in any case for spreading open can also be used as a rotation lock when the first longitudinal bolt section has an associated protrusion or fin.

[0020] A screw connection as claimed in claims 6 to 9 is also subject matter of the invention.

[0021] As already explained above, according to a preferred configuration of the invention, the sleeve has a first longitudinal sleeve section and a second longitudinal sleeve section, -5- 2013339553 07 Oct 2016 wherein the first longitudinal sleeve section is provided for radial bracing in a manner interacting with the bolt, and wherein the second longitudinal sleeve section is provided with an external thread such that the sleeve can be braced in the longitudinal direction by way of a sleeve nut. From a practical point of view, it may be expedient for a step-like transition to be provided between the first longitudinal sleeve section and the second longitudinal sleeve section. While the first longitudinal sleeve section, at least after it has been spread open, is usually intended to entirely fill the corresponding fastening openings, the second longitudinal sleeve section has a smaller outside diameter. In the case of the screw connection according to the invention, this step-like transition is arranged preferably outside the fastening opening of the second part, wherein the step-like transition is concealed by a washer arranged between the outer surface of the second part and the sleeve nut. In particular, it is possible to provide a specially adapted washer which also has a step shape.

[0022] In the case of the described configuration having a step-like transition, the longitudinal slits preferably extend along the entire length of the first longitudinal sleeve section into the region of the step-like transition in order to allow the first longitudinal sleeve section to be spread open readily.

[0023] The fastening opening of the first part and that of the second part can be configured in a circular-cylindrical manner as conventional bores. Furthermore, however, it is also possible for the fastening opening of the first part and that of the second part each to narrow conically in the direction of the second side, wherein the sleeve that bears by way of its collar against an outer surface of the first part is then spread open by way of its first longitudinal sleeve section to such an extent that said sleeve is adapted to the conical shape of the fastening openings.

[0024] Of course, it is also possible, by way of the screw connection arrangement according to the invention, to connect more than two parts which are located one over the other. For example, it is also possible to arrange between the first part and the second part a third part which is then also connected thereto.

[0025] The invention is explained in the following text with reference to a drawing which illustrates merely one exemplary embodiment.

[0026] The single figure shows a screw connection in which a first part 1 is arranged on a first side and a second part 2 is arranged on a second side, wherein the first part 1 and the -6- 2013339553 07 Oct 2016 second part 2 are connected at circular-cylindrical fastening openings by way of a screw connection arrangement.

[0027] The screw connection arrangement comprises a sleeve 3 and a bolt 4.

[0028] At a first sleeve end, the sleeve 3 has a radially protruding collar 5 and, starting from the first sleeve end, a first longitudinal sleeve section 6. The longitudinal sleeve section 6 is provided with longitudinal slits 7 such that the first longitudinal sleeve section 6 is able to be spread open in the radial direction. Preferably between three and eight longitudinal slits 7 are provided around the circumference. Starting from the first sleeve end, the inside diameter narrows conically along the first longitudinal sleeve section 6.

[0029] The first longitudinal sleeve section 6 extends through the fastening opening of the first part 1 and the fastening opening of the second part 2. Provided outside the fastening opening of the second part 2 is a step-like transition 8 which is adjoined by a second longitudinal sleeve section 9, arranged outside the fastening openings, with an external thread. A sleeve nut 10, by way of which the sleeve 3 is braced against an outer surface of the second part 2 via a washer 11, has been screwed onto the external thread of the second longitudinal sleeve section 9. Thus, a form-fitting connection of the first part 1 and of the second part 2 in the axial direction x is achieved.

[0030] The bolt 4 has a first longitudinal bolt section 12 and a second longitudinal bolt section 13. The first longitudinal bolt section 13 has been inserted into the first longitudinal sleeve section 6 and has a conically narrowed outer surface in the direction of a second end of the bolt 4, that is to say in the direction of the second longitudinal bolt section 13. The conical shape of the first longitudinal bolt section 12 is adapted to the conically extending inside diameter of the first longitudinal sleeve section 6. When the first longitudinal bolt section 12 is inserted further into the first longitudinal sleeve section 6 in the direction of the narrowing, the first longitudinal sleeve section 6 is spread open in the radial direction r on account of the longitudinal slits 7. For this purpose, an external thread, onto which a bolt nut 14, which is supported on an end face 15 of the second longitudinal sleeve section 9, has been screwed, is formed on the second longitudinal bolt section 13. Arranged between the end face 15 and the bolt nut 14 is a further washer or, as illustrated in the exemplary embodiment, a lock washer 16.

[0031] When both the bolt nut 14 and the sleeve nut 10 have been tightened, a precise, reliable and firm connection of the first part 1 and the second part 2 is achieved. The radial 2013339553 07 Oct 2016 -7- clearance that is initially necessary for inserting the sleeve 3 is eliminated during the tightening of the bolt nut 14 in that the first longitudinal sleeve section 6 is expanded by the first longitudinal bolt section 12.

[0032] According to the invention, a particularly advantageous combination results from a form fitting and frictional connection. The axial bracing of the sleeve 3 by way of the sleeve nut 10 results initially in a form fit in the axial direction. A friction fit is produced in the transverse direction or radial direction r, that is to say at the contact face between the first part 1 and the second part 2, by the axial application of force.

[0033] When the outer lateral surface of the first longitudinal sleeve section 6 is pressed against the internal circumference of the fastening openings when the bolt nut 14 is tightened, a clearance-free form fit is also achieved in the radial direction r, that is to say in the transverse direction, wherein a friction fit that acts in the axial direction x is additionally also achieved by the clamping of the lateral surface of the first longitudinal sleeve section against the internal circumference of the first part 1 and of the second part 2.

Claims

1. A screw connection arrangement having a sleeve which has a radially protruding collar at a first sleeve end and a first longitudinal sleeve section starting from the first sleeve end, wherein the first longitudinal sleeve section is able to be spread open by way of longitudinal slits and has a conically narrowing inside diameter starting from the first sleeve end, and a bolt which has been inserted into the first longitudinal sleeve section with a first longitudinal bolt section and has, at a second end of the bolt (4), a second longitudinal bolt section with a thread onto which a bolt nut has been fitted, said second longitudinal bolt section extending at least partially out of the sleeve, wherein the first longitudinal bolt section narrows conically in the direction of the second end of the bolt, wherein an external thread for receiving a sleeve nut is provided on a second longitudinal sleeve section, starting from a second sleeve end, and wherein an end face at the second sleeve end forms an abutment face for the bolt nut.

2. The screw connection arrangement as claimed in claim 1, wherein the collar has a tool receiving surface on its outer circumference.

3. The screw connection arrangement as claimed in claim 1 or claim 2, wherein the bolt has a tool receptacle at its first and/or second end.

4. The screw connection arrangement as claimed in any one of claims 1 to 3, wherein a form-fitting rotation lock is formed at the conically narrowing first longitudinal bolt section and the associated first longitudinal sleeve section.

5. A screw connection having a first part on a first side and having a second part on a second side, which are connected at a respective fastening opening by way of a screw connection arrangement as claimed in any one of claims 1 to 4.

6. The screw connection as claimed in claim 5, wherein the sleeve bears by way of its collar against an outer surface of the first part and is braced, on the opposite second side, against an outer surface of the second part via a sleeve nut at a second longitudinal sleeve section provided with an external thread, wherein the first longitudinal sleeve section, provided with longitudinal slits, is spread open by the conical first longitudinal bolt section in that the second longitudinal bolt section is clamped against an end face at the second sleeve end by way of a bolt nut, and wherein a lateral surface of the first longitudinal sleeve section bears at least sectionally against an internal circumference of the fastening openings of the first part and of the second part.

7. The screw connection as claimed in claim 6, wherein, outside the fastening opening of the second part, the sleeve has a step-like transition between the first longitudinal sleeve section and the second longitudinal sleeve section, wherein the step-like transition is concealed by a washer) arranged between the outer surface of the second part and the sleeve nut.

8. The screw connection as claimed in any one of claims 5 to 7, wherein the fastening opening of the first part and that of the second part each narrow conically in the direction of the second side.

9. A method for connecting two parts by way of a screw connection arrangement as claimed in any one of claims 1 to 5, wherein the parts are positioned one over the other with a respective fastening opening, wherein the sleeve is inserted with a radial clearance into the fastening openings located one over the other, such that the radially protruding collar is supported on the first part, wherein the bolt is or has been inserted into the sleeve and radially spreads open the longitudinal sleeve section provided with longitudinal slits by tightening of a bolt nut.