EP1591207B1 - Spring tensioner for tensioning a helical compression spring - Google Patents

Abstract

A replacement helical spring (2) forms part of an automotive shock absorber assembly and is presented for re-assembly in a non-tensioned condition. The spring is placed under tension for re-assembly by a compression tool (3) with an integral threaded spindle (4) with two end plates (7, 8) whose position relative to each other is varied by rotation. The plates further incorporated peripheral detents (30, 54) on their inner faces (24, 49) that engage with the spring tips.

Description

The invention relates to an inner tensioner for tensioning a helical compression spring according to the features in the preamble of claim 1.

From the prior art internal tensioner for helical compression springs are known in particular for the motor vehicle sector, with which these helical compression springs can be dismantled from corresponding recordings of the chassis and also used again.

The DE 37 20 018 discloses a generic internal tensioner for helical compression springs, which consists of a centrally positionable within a tensioning spring to be clamped and variable by means of a clamping drive in its effective length clamping element and two axially against the clamping element supporting pan plates to rest on each spring coil of the helical compression spring. Both clamping plates have a central bore, wherein the drive-side 1. Spannteller supported in the assembled state with a recess on the outside of a shoulder of the clamping element. The tensioning element comprises a threaded spindle in a threaded tube, a drive being provided at a first end of the tensioning element and fingers projecting radially outward at the opposite, second end. The second clamping plate to be mounted on the clamping element on the second end, which is occupied by radial fingers, has recesses projecting radially outward from the central bore and forming a common, approximately star-shaped opening with the central bore, so that the radial finger occupies 2. End of the clamping element can be passed through the opening formed thereby. Offset at an angle to the outwardly projecting recesses of the second clamping plate depressions are introduced into the outer side of the second clamping plate, in which the radial fingers are held in a form-fitting manner in the assembled state of the inner clamp.

In practical use shows that the installation of this internal tensioner consuming and especially the threading of the provided with the radial fingers 2nd end of the clamping element with respect to a series assembly is difficult to act.

Although the radial fingers and the depressions allow a certain relative pivoting of the threaded tube to the second clamping plate. Due to the principle in three-point support of the radial fingers in the wells of the 2nd clamping plate, however, it can come to a lift when panning. As a result, a secure clamping a helical compression spring is not guaranteed.

The spring coils of the helical compression spring are secured against radial sliding away from the insides of the clamping plates by annular segment-shaped collars provided on the outer circumference of the clamping plates.

This design leads to some suspension problems to disassembly and reassembly of a helical compression spring, because the necessary space is not available.

The DE 42 36 690 discloses a generic internal tensioner for helical compression springs, which is positionable with two clamping plates in a helical compression spring. The voltage is supplied by an internal spindle drive. The clamping plate and the spindle drive are connected to each other via ball-like thickenings. Thus, a rotation between the thickened end and the clamping plate is not possible, the spindle drive has a square, which engages in a complementary square hole of the clamping plate. A disadvantage of this embodiment is that only a small pivotability of the clamping drive to the clamping plate can be realized.

From the US 3,256,594 is an internal tensioner for tensioning helical compression springs disclosed in which two pressure plates are clamped by a spindle drive. The pressure plates each engage in the helical compression spring with a bead adapted to the turn of the helical compression springs. The connection between the spindle drive and pressure plates consists of a surface-lying, washers similar bead. A disadvantage of this invention is that no Relativverschwenkung between the pressure plate and spindle drive is possible.

From the DE 201 01 841 is a Innenfederspanner with two pressure plates for tensioning helical compression springs known. Again, a relative movement of the pressure plates is generated via a spindle drive, which in turn brings a voltage of the coil springs with it. The spindle drive engages at its ends via a thickening in the printing plates. To prevent twisting, the respective pressure plate has an internal hexagonal shape. This has the disadvantage that also here a Relativverschwenkung is not possible.

From the DE 197 08 586 a spring tensioner is known with which a tension of a helical compression spring of a motor vehicle is made possible. The spring tensioner is a spring-directed axial guide device with an inner spindle drive. This embodiment requires an extremely large amount of working space and is complicated to mount on the helical compression spring. Furthermore, a pivoting of pressure plate to spindle drive is not possible.

From the EP 0 484 215 is an external spring tensioner known for tensioning a helical compression spring in a motor vehicle. This outer tensioner has the disadvantage that it is difficult to install in installation locations with little mounting space or is not mountable.

The invention is - starting from the prior art - the object to provide an inner tensioner for tensioning a helical compression spring, a perfect disassembly and assembly of a helical compression spring and Relativverschwenkungen between the tensioning drive and loaded by the helical compression spring tensioning discs even with tight mounting spaces a perfect Guaranteed clamping of a helical compression spring.

This object is achieved with the features listed in the characterizing part of claim 1.

In order to be able to effectively counteract problems when tensioning a helical compression spring in the area of the clamping plates, the invention now provides that both clamping plates are provided on the mutually facing inner sides with contact surfaces for spring coils whose inclinations are aligned in the circumferential direction of the clamping plate of the pitch of the helical compression spring. Furthermore, it is important in this context that the footprints are limited to the central axes of the clamping plate through capturing in spring coils annular beads. This means that the spring coils did not encompass the outer circumference of the clamping plate provided there collar are, but only at the inner periphery properly centered by the positively engaging in the spring coils annular beads. As a result, both the dismantling and the assembly is facilitated even in tight spaces of a chassis. Slippage of the helical compression spring from the clamping plates is reliably prevented.

The displacement of the central axis of the annular bead on the 1st clamping plate to the common center axis of the first clamping plate and the central opening in the direction away from the edge-side recess has the advantage that in certain installation situations of a helical compression spring inner tensioner can be considered cheaper.

The invention is both with advantage in an inner tensioner noticeable, in which the tensioning drive consists of a central threaded spindle, a threaded spindle displaceable along the threaded sleeve and a longitudinal portion of the threaded spindle and the threaded sleeve cross-protective sleeve, wherein the protective sleeve with the 1st clamping plate and the free end of the threaded sleeve can be coupled to the 2nd clamping plate, as well as an inner clamp with a threaded spindle, a pressure piece and a clamping nut, with a 2nd end of the threaded spindle with the 2nd clamping plate and the pressure piece with a 1st clamping plate are coupled.

According to the features of claim 2, a first clamping plate is circumferentially provided on the central side of the clamping drive on the outside facing away from the annular bead with a spherical segmental dome for engaging a pressure surface adapted thereto at a pressure piece of the clamping drive. In this way, relative pivoting movements between the loaded by the helical compression spring 1st clamping plate and the pressure piece can be taken into account.

Due to the adaptation of the footprints on the tension plates to the pitch of the helical compression spring, it is sufficient according to the features of claim 3, when the edge-side segment-like recesses of Spans only extend over an angle of about 90 °. The spring wire of a helical compression spring can thereby be easily transferred from one to the other side of the clamping plate. The recesses in the circumferential direction delimiting surfaces extend in radial planes which extend through the central axis of the annular bead and the second clamping plate through the central axis of the first clamping plate.

In a further development of the invention, the pressure piece is displaceable by a clamping nut on a threaded spindle of the clamping drive according to claim 4. Between the pressure piece and the clamping nut, a thrust bearing is provided, in particular in the clamping nut, so that no significant frictional forces between the clamping nut and the pressure piece occur.

According to the features of claim 5, a second clamping plate is provided with a transverse slot, the inner end is designed circular section, wherein on the side facing away from the annular bead a dome is provided, which is composed of spherical segment-shaped inner surfaces of different sizes, which of their configuration forth spherical segment-shaped surfaces are aligned at a second end of the tensioning drive. In this way, a nearly full-surface investment of the second end of the tensioning drive is achieved in the calotte and that in all pivot positions of the clamping drive relative to the second clamping plate. The second end forms a sort of pendulum head of the tensioning drive.

The second end of the tensioning drive is spherical and its flat end face is limited on the circumference of straight edges and circular section-shaped transition edges. From the straight edges on the one hand and the circular section-shaped transition edges on the other hand, spherical segment-shaped surfaces extend in the direction of the longitudinal axis of the clamping drive. These surfaces are designed so that the radius of the surfaces between the straight edges and the longitudinal axis is greater than the radius of the surfaces between the transition edges and the longitudinal axis is dimensioned. By contrast, the radius of all inner surfaces of the dome corresponds to the radius of the surfaces between the straight edges and the longitudinal axis.

The length of the larger radius surfaces measured in the circumferential direction of the second end of the tensioning drive is about six times the length of the smaller radius surfaces.

A twist-proof embedding of the second end of the tensioning drive in the calotte of the second clamping plate is achieved according to the features of claim 6, characterized in that the inner surfaces of the dome with straight edges and circular-segment-shaped transition edges open into the dome of the adjacent outer side of the second clamping plate.

According to the features of claim 7, two constrictions separated by a peripheral bead are provided on a shaft-like longitudinal section of the tensioning drive adjacent to the second end. The diameter of these constrictions is smaller than the width of the transverse slot in the 2nd clamping plate. Although the diameter of the peripheral bead is larger than the width of the transverse slot dimensioned, but smaller than the diameter of the circular portion-shaped inner end of the transverse slot. In this way, the second clamping plate can be easily inserted transversely between two spring coils of the helical compression spring. Subsequently, the tensioning drive can then be displaced in the longitudinal direction of the helical compression spring until the second end engages in the calotte of the second clamping plate. Thereafter, the helical compression spring between the 1st and the 2nd clamping plate can be clamped by means of the tensioning drive.

To allow an installer to be able to apply tools for twisting or countering at both ends of the tensioning drive, see the features of claim 8, that at the first end and / or at the second end of the clamping drive projections are provided with key surfaces.

An expedient design of the tensioning drive is ultimately characterized according to claim 9, that the thickened second end, the constrictions and the peripheral bead are provided directly on the threaded spindle of the tensioning drive. The threaded portion of the threaded spindle is provided with a longitudinal groove for receiving a sliding spring as part of the longitudinally displaceable with a clamping nut pressure piece of the clamping drive.

Figur 1

die Einzelteile eines Innenspanners zum Spannen einer Schraubendruckfeder, teilweise in schematischer Perspektive, teilweise in schematischer Ansicht;

Figur 2

eine Frontalansicht auf die Innenseite eines 1. Spanntellers des Innenspanners der Figur 1;

Figur 3

eine Seitenansicht auf den 1. Spannteller der Figur 2 in Richtung des Pfeils III gesehen;

Figur 4

einen vertikalen Querschnitt durch die Darstellung der Figur 2 entlang der Linie IV - IV in Richtung der Pfeile IVa gesehen;

Figur 5

in der Seitenansicht einen Längenabschnitt des Innenspanners der Figur 1 vor der Kopplung mit einem 2. Spannteller;

Figur 6

eine Draufsicht auf die Darstellung der Figur 5 in Richtung des Pfeils VI gesehen, teilweise im Schnitt;

Figur 7

eine Frontalansicht auf die Innenseite des 2. Spanntellers zur Kopplung mit dem Längenabschnitt des Innenspanners der Figuren 5 und 6;

Figur 8

in der Perspektive eine Ansicht auf die Außenseite des 2. Spanntellers und

Figur 9

eine Seitenansicht des 2. Spanntellers in Richtung des Pfeils IX der Figur 7 gesehen.

The invention is explained in more detail with reference to an embodiment shown in the drawings. Show it:

FIG. 1

the items of an internal tensioner for tensioning a helical compression spring, partially in schematic perspective, partially in schematic view;

FIG. 2

a frontal view of the inside of a 1st clamping plate of the inner tensioner of FIG. 1 ;

FIG. 3

a side view of the 1st Spandeller the FIG. 2 seen in the direction of arrow III;

FIG. 4

a vertical cross section through the representation of FIG. 2 along the line IV - IV seen in the direction of arrows IVa;

FIG. 5

in the side view, a longitudinal section of the inner tensioner of FIG. 1 before coupling with a second clamping plate;

FIG. 6

a plan view of the representation of FIG. 5 seen in the direction of the arrow VI, partly in section;

FIG. 7

a frontal view of the inside of the second clamping plate for coupling with the length of the inner section of the FIGS. 5 and 6 ;

FIG. 8

in perspective, a view on the outside of the 2nd clamping plate and

FIG. 9

a side view of the second clamping plate in the direction of arrow IX of FIG. 7 seen.

With 1 is in the FIG. 1 generally referred to an inner clamp for tensioning a helical compression spring 2, which is used for example for disassembly and assembly of a helical compression spring 2 is used, which forms part of a chassis of a motor vehicle.

The inner tensioner 1 is composed of a tensioning drive 3 with threaded spindle 4, pressure piece 5 and clamping nut 6, as well as of two clamping plates 3, 8 which can be coupled to the tensioning drive 3.

The from the FIGS. 1 . 5 and 6 recognizable threaded spindle 4 has over most of its length a threaded portion 9 with a rectangular thread 10 (FIG. FIG. 6 ) on. At a first end 11 of the threaded spindle 4 is a projection 12 with key surfaces 13 for applying a tool ( FIG. 1 ).

The threaded portion 9 is penetrated at the periphery parallel to the longitudinal axis 14 of the threaded spindle 4 by a longitudinal groove 15 ( FIGS. 1 and 5 ). The longitudinal groove 15 is used to engage a sliding spring 16, which is located in the pressure piece 5 ( FIG. 1 ). The pressure piece 5 can slide over the threaded portion 9. It lies with a ring gear 17 on a thrust bearing, which is inserted into a sleeve-like longitudinal portion 18 of the clamping nut 6. The thrust bearing is not shown in detail. The clamping nut 6 can be displaced over key surfaces 19 with the aid of a suitable tool along the threaded portion 9.

At the other end, the pressure piece 5 has a ball-shaped pressure surface 20 for engagement in a correspondingly configured dome 21 on the periphery of a central opening 22 in the 1st clamping plate 7 (FIG. FIGS. 1 to 4 ). The calotte 21 opens into the outer side 23 of the first clamping plate 7. On the inner side 24 facing away from the calotte 21, the first clamping plate 7 has an annular bead 25 for engagement in a spring coil 26. The annular bead 25 passes over a curved concave groove 27 in one Contact surface 28 via, which merges into the outer periphery 29 of the first clamping plate 7 without any projection. The slope of the footprint 28 is adapted to the pitch of the helical compression spring 2.

The edge-side recess 30 on the 1st clamping plate 7 is used to transfer the spring wire of the helical compression spring 2 from the inside 24 to the outside 23. The common center axis of the first clamping plate 7 and the central opening 22 is denoted by 57. As the FIGS. 2 and 4 can be seen beyond, the central axis 58 of the annular bead 25 is offset by the amount x to the common center axis 57 of the 1st clamping plate 7 and the central opening 22 in the direction away from the edge-side recess 30 direction.

The recess 30 circumferentially bounding surfaces 59 extend in radial planes which intersect the central axis 58 of the annular bead 25. In the circumferential direction, the recess 30 extends between the surfaces 59 through an angle α of 90 °.

The threaded portion 9 of the threaded spindle 4 is according to the particular FIGS. 1 . 5 and 6 in a shaft-like longitudinal section 31 via. This has a constriction 32, to which a circumferential bead 33 connects. Between the peripheral bead 33 and a thickened second end 34 of the threaded spindle 4 is a further constriction 35. The diameter D of the constrictions 32, 35 is sized equal.

The second end 34 is hemispherical. Its flat end face 36 is bounded on the circumference by straight edges 37 and circular-segment-shaped transition edges 38. From the straight edges 37, surfaces 39 extend in Direction to the longitudinal axis 14 of the threaded spindle 4. Narrow spherical segment-shaped surfaces 40 extend from the circular section-shaped transition edges 38 in the direction of the longitudinal axis 14. The radius R of the surfaces 39 between the straight edges 37 and the longitudinal axis 14 is greater than the radius R _{1 of} the surfaces 40th between the transition edges 38 and the longitudinal axis 14 dimensioned. The length of the surfaces 39 with the larger radius R measured in the circumferential direction of the second end 34 corresponds approximately to six times the length of the surfaces 40 with the smaller radius R ₁ .

Front side of the second end 34, a projection 41 is provided with key surfaces 42 for applying a tool.

With the thickened second end 34 of the threaded spindle 4, the second clamping plate 8 can be coupled, which from the FIGS. 1 and 7 to 9 is more clearly recognizable. The second clamping plate 8 has a transverse slot 43, the inner end 44 is formed in a circular section. On the circumference of the inner end 44, a dome 46 is formed adjacent to the outer side 45 and is provided with wider inner surfaces 47, which are adapted to the configuration of the surfaces 39, 40 of the second end 34 and narrower inner surfaces 48. The radius of all inner surfaces 47, 48 of the cap 46 corresponds to the radius R of the surfaces 39 between the straight edges 37 and the longitudinal axis 14 at the second end 34.

Furthermore, let the FIGS. 1 . 7 and 9 recognize that the second clamping plate 8 is provided on the inner side 49 facing away from the cap 46 with a footprint 50 for a spring coil 26 of the helical compression spring 2, the slope is aligned in the circumferential direction of the second clamping plate 8 of the pitch of the helical compression spring 2. The footprint 50 is limited to the central axis 51 of the second clamping plate 8 out through an engaging in a spring coil 26 annular bead 52. The footprint 50 goes vorsprungslos in the outer periphery 53 of the second clamping plate 8 over.

The recess 54 in the outer periphery 53 of the second clamping plate 8 serves for the passage of the spring wire of the helical compression spring 2 from the inner side 49 to the outer side 45. It extends over an angle β of 90 °. The recess 54 bounding in the circumferential direction surfaces 60 extend in radial planes which intersect the central axis 51 of the second clamping plate 8.

The diameter D of the constrictions 32, 35 on the shaft-like longitudinal portion 31 of the threaded spindle 4 is smaller than the width B of the transverse slot 43 in the second clamping plate 8 dimensioned. The diameter D _{1 of} the peripheral bead 33 is greater than the width B of the transverse slot 43, but smaller than the diameter D _{2 of} the circular section-shaped inner end 44 of the transverse slot 43 (FIG. FIG. 7 ).

The surfaces 47 of the cap 46 open with straight edges 55 and the surfaces 48 with circular section-shaped transition edges 56 in the outer side 45 of the second clamping plate 8 (FIGS. FIG. 8 ).

To tighten the helical compression spring 2, the first clamping plate 7 is first inserted transversely between two spring coils 26. Subsequently, the threaded spindle 4 is pushed in the longitudinal direction of the helical compression spring 2 through the central opening 22 of the 1st clamping plate 7 and then provided with the pressure piece 5 and the clamping nut 6. Subsequently, the second clamping plate 8 is also threaded transversely between two spring coils 26 of the helical compression spring 2, the constriction 32 in the transverse slot 43 sums. Thereafter, the threaded spindle 4 can be rotated in the longitudinal direction, wherein the peripheral bead 33 slides through the inner end 44 of the transverse slot 43 until the second end 43 sums in the cap 46 of the second clamping plate 8. Now, by rotating the clamping nut 6, the helical compression spring 2 between the 1st clamping plate 7 and the second clamping plate 8 axially tensioned, ie be shortened. By the annular beads 25 and 52, the helical compression spring 2 is securely fixed in position.

REFERENCE NUMBERS

1 -

interior tensioner

2 -

Helical compression spring

3 -

tensioning drive

4 -

screw

5 -

Pressure piece

6 -

locknut

7 -

1st clamping plate

8th -

2. Spannteller

9 -

Thread section v. 4

10 -

square thread

11 -

1st end of v. 4

12 -

Lead at 11

13 -

Wrench flats at 12

14 -

Longitudinal axis v. 4

15 -

Longitudinal groove in 4

16 -

Sliding spring in 5

17 -

Ring wreath at 5

18 -

Length section v. 6

19 -

Wrench flats to 6

20 -

Printing area at 5

21 -

Dome in 7

22 -

Breakthrough in 7

23 -

Outside v. 7

24 -

Inside v. 7

25 -

Ring bulge at 24

26 -

spring coil

27 -

Throat at 7

28 -

Contact patch at 7

29 -

Outer circumference v. 7

30 -

Recess at 7

31 -

Length section v. 4

32 -

Constriction at 31

33 -

Bulge at 31

34 -

2nd end of v. 4

35 -

Constriction at 31

36 -

Front side v. 34

37 -

straight edges

38 -

Transition edges

39 -

Surfaces on 34

40 -

Surfaces on 34

41 -

Lead on 34

42 -

Key surfaces on 41

43 -

Transverse slot in 8

44 -

inner end v. 43

45 -

Outside v. 8th

46 -

Dome in 45

47 -

Inner surfaces v. 46

48 -

Inner surfaces v. 46

49 -

Inside v. 8th

50 -

Contact area at 49

51 -

Central axis v. 8th

52 -

Ring bead on 49

53 -

Outer circumference v. 8th

54 -

Recess at 8

55 -

straight edges v. 47

56 -

Transitional edges v. 48

57 -

Central axis v. 7

58 -

Central axis v. 25

59 -

Areas v. 30

60 -

Areas v. 54

B -

Width v. 43

D -

Diameter v. 32, 35

D1 -

Diameter v. 33

D2 -

Diameter v. 44

R -

Radius v. 39

R1 -

Radius v. 40

α -

Angle between 59

β -

Angle between 60

Claims (9)

1. Internal tensioner (1) for tensioning a helical compression spring (2), which forms in particular a component of a chassis of a motor vehicle, with a tensioning drive (3) with integrated threaded spindle (4) and a first tensioning plate (7) and a second tensioning plate (8) which are displaceable in relation to each other and provided with segment-like recesses (30, 54) on their edges, wherein the tensioning plates (7, 8) are provided, on the inner sides (24, 49) facing towards each other, with contact surfaces (28, 50) adapted to the gradient of the helical compression spring (2), which graduate without any overhang into an outer perimeter (29, 53) of the tensioning plates (7, 8), but are limited towards the central axes (57, 51) of the tensioning plates (7, 8) by annular beads (25, 52) engaging so as to interlock in spring windings of the helical compression spring (2), characterised in that one central axis (58) of the annular bead (25) on the first tensioning plate (7) is offset in relation to the common central axis (57) of the first tensioning plate (7) and to a central hole (22) in the direction away from the recess (30) at the edge.
2. Internal tensioner according to claim 1, characterised in that the first tensioning plate (7) is provided at the periphery of a central hole (22) for the tensioning drive (3) on an outer side (23) facing away from the annular bead (25) with a cap (21) in the shape of a spherical segment for meshing a pressure surface (20) adapted thereto on a pressure piece (5) of the tensioning drive (3).
3. Internal tensioner according to one of claims 1 to 2, characterised in that the segment-like recesses (30, 54) extend over an angle (α, β) of about 90°.
4. Internal tensioner according to one of claims 2 to 3, characterised in that the pressure piece (5) is displaceable on a threaded spindle (4) of the tensioning drive (3) by a tensioning nut (6).
5. Internal tensioner according to one of claims 1 to 4, characterised in that the second tensioning plate (8) is provided with a lateral slot (43), the inner end (44) of which is in the form of a segment of a circle, while a cap (46) is provided on an outer side (45) facing away from the annular bead (52), said cap being composed of spherical segment-shaped inner surfaces (47, 48) of different sizes which are aligned in terms of their configuration to surfaces in the form of spherical segments (39, 40) on a second end (34) of the tensioning drive (3) which can be coupled with the second tensioning plate (8).
6. Internal tensioner according to claim 5, characterised in that the inner surfaces (47, 48) of the cap (46) in the second tensioning plate (8) with straight edges (55) and graduated edges (56) in the form of a segment of a circle, lead into the outer side (45) of the second tensioning plate (8) adjacent the cap (46).
7. Internal tensioner according to claim 5 or 6, characterised in that two constrictions (32, 35) separated from each other by a peripheral bead (33) are provided on a shaft-like longitudinal section (31) of the tensioning drive (3) adjacent the second end (34), the diameter (D) of said constrictions being less than the width (B) of the lateral slot (43) in the second tensioning plate (8), the diameter (D1) of the peripheral bead (33) being greater than the width (B) of the lateral slot (43), but less than the diameter (D2) of the inner end (44) of the lateral slot (43) in the form of a segment of a circle.
8. Internal tensioner according to claim 7, characterised in that overhangs (12, 41) with spanner surfaces (13, 42) are provided on the first end (11) and/or on the second end (34) of the tensioning drive (3).
9. Internal tensioner according to claim 8, characterised in that the second end (34), designed as a thickened end, the constrictions (32, 35) and the peripheral bead (33) are provided directly on the threaded spindle (4) of the tensioning drive (3) and one threaded section (9) of the threaded spindle (4) is provided with a longitudinal groove (15) to take a sliding key (16) as a component of a pressure piece (5) which is displaceable along the threaded section (9) with the tensioning nut (6).

Images