DE29801172U1 - Spring tensioner for coil springs with a low number of turns - Google Patents

Description

Description: Spring compressor for coil springs with a low number of turns

The invention relates to a spring tensioner for tensioning a coil spring which is arranged between an upper and a lower spring plate of a spring damper leg.

Motor vehicles are received under pre-tension, consisting of a first and a second gripper element, which are arranged coaxially to one another on a guide tube of the spring tensioner and can be displaced relative to one another in the axial direction of the guide tube by means of an actuator of the guide tube, wherein the first gripper element for receiving the spring plate is designed approximately in a circular ring shape and wherein the second gripper element is designed approximately in a fork shape and can be brought into engagement with a spring turn of the coil spring for tensioning the coil spring.

A spring tensioner of the generic type is known (EP 0 349 776 Bl) in particular for tensioning axle springs of motor vehicles, which consists of a cylindrical guide tube with a threaded spindle rotatably mounted therein.

Neymeyer & Partner GbR, patent attorneys

MN

.if.

1998

del as an actuator and two gripper elements. The first gripper element is firmly attached to one end of the guide tube by means of a cylindrical holding element, the gripper element being interchangeably coupled to the holding element via a coupling piece. The second gripper element is interchangeably connected to a second holding element via a second coupling piece, the second holding element being axially displaceable along the guide tube together with the second gripper element by the actuator to tension a coil spring.

The first gripper element has the form of a closed, L-shaped profiled ring, which can be placed on top of a spring plate of a spring damper leg that accommodates the upper end of the coil spring. The inner ring surface of the profiled ring, on which the spring plate comes to rest during the tensioning process, can have several centering stages, so that spring plates of different sizes can be accommodated with the same gripper element.

The second gripper element is roughly fork-shaped and also has an L-shaped profile in cross-section. The two fork legs of this gripper element form a roughly circular ring element that is open to the coupling element and has an almost helical shape. The two gripper elements

Neymeyer & Partner GbR, patent attorneys

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elements are arranged on the guide tube in such a way that their central connecting axis runs parallel to the longitudinal center axis of the guide tube. This means that a coil spring clamped between the gripper elements is also aligned with its longitudinal center axis parallel to the guide tube. During the tensioning process, the second gripper element is first brought into engagement with one of the spring coils in the lower area of the coil spring, while the first gripper element is placed on the upper spring plate at the same time or beforehand. When the threaded spindle is operated, the lower second gripper element is moved along the guide tube towards the first gripper element, so that their distance is reduced and the coil spring is shortened and thus tensioned.

However, the well-known spring tensioner with its gripping elements can only be used to a limited extent for tensioning coil springs with a large pitch. In the case of spring damper legs that have such coil springs with a large pitch, e.g. in lowered vehicles, this spring pitch continues up to the end turns of the coil spring, so that the upper spring plate of the spring damper leg in particular has a radially outward-projecting and circumferential support web to accommodate the last spring turn, which in the circumferential direction is adapted to the pitch of the spring turn at least in some areas. In the receiving area for the end of the

Neymeyer & Partner GbR, Patent Attorneys MN

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In the case of a coil spring, the support web has a corresponding shoulder that is adapted to the diameter of the spring wire and runs approximately at right angles to the support surface for the spring coil formed by the support web. In the case of spring plates that are made from sheet steel, the outer top of the spring plate or the support web also has a shape that is adapted to the spring pitch. Since the upper surface that is to be taken up by the gripper element for tensioning the coil spring also has a shape that is adapted to the pitch of the spring coil, centered tensioning of the coil spring is at least made more difficult, since the flat ring surface of the known gripper element can slip away on the spring plate during the tensioning process. Furthermore, the gripper element can become jammed on the holding element of the guide tube due to the inclination or pitch of the spring plate, since the gripper element cannot be placed flat on the spring plate. Such a jamming leads to a higher load on the coupling between the holding element and the coupling piece of the gripper element, which increases the risk of the gripper element breaking, which is associated with a risk to the operating personnel. Such a jamming can occur due to the large pitch of the spring coils, which are brought into engagement with the second gripper element to tension the coil spring.

Neymeyer & Partner GbR. Patent Attorneys ·**··

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can also occur with the second gripper element, since this has only a slight gradient in the known spring tensioner.

Accordingly, the invention is based on the object of designing a spring tensioner of the generic type in such a way that the tensioning of coil springs with a large pitch of the spring coils can be carried out safely.

The object is achieved according to the invention in that the first gripper element has at least one support surface adapted to the contour of the upper spring plate, so that during the clamping process the upper spring plate rests flatly in the gripper element at least over a support angle of at least approximately 180°.

The design according to the invention provides a gripper element for a spring tensioner in which a spring plate with a rising support surface for a coil spring and a height offset for receiving the end of the spring plate-side spring coil of the coil spring can be accommodated in a centered manner. Due to the shape adaptation to the contour of the support surface of the spring plate at least in some areas, the spring plate is simultaneously aligned approximately transversely to the longitudinal center axis of the coil spring to be tensioned during tensioning, so that the coil spring cannot evade or bulge in the area

Neymeyer & Partner GbR, patent attorneys

1998

between the first and the second gripper element is safely prevented during the clamping process.

The shape adjustment should take place in a circumferential area of at least approximately 180°, so that a centered reception of the spring plate is ensured. Depending on the design of the spring plate, this shape adjustment can of course also take place over a circumferential area of more than 180° up to 360°. If the shape adjustment only takes place over a circumferential area of approximately 180°, the gripper element according to the invention can still be used for spring plates whose outer surface is flat, since the remaining circumferential area is also flat and thus a spring plate that is flat on the outside is safely guided during clamping. The outside of the spring plate is the side of the spring plate that is opposite a coil spring received by the spring plate.

The one-piece design of the gripper element with the support surface for the spring plate according to claim 2 ensures cost-effective production of the gripper element.

Due to the design according to claim 3, the support surface can, as an alternative to the design according to claim 2, also be part of a special insert ring that can be inserted into the first gripper element, thus enabling an adaptation

Nevmeyer & Partner GbR, Patent Attorneys

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Adaptation to different shapes of differently designed spring plates can be carried out easily by exchanging insert rings with correspondingly differently adapted shapes.

Such a variable application of the first gripper element is also achieved by the design according to claim 4, according to which the gripper element has several support surfaces with different diameters and different surface shapes. Because the larger support surface forms a circumferential centering shoulder for the adjacent smaller support surface, corresponding spring plates are guided centered on each of the support surfaces, whereby a high degree of operational reliability is achieved.

Since a spring plate with a rising outer contour and with a height offset is often used for springs with a large pitch, the operational reliability is further increased by the design of the second gripper element according to claim 5. The fork-shaped second gripper element therefore has a support surface, the pitch of which corresponds to a pitch of a spring coil of a helical spring to be gripped, which is clamped between the two spring plates of a spring damper leg in the unloaded state of the spring damper leg.

Through this special adjustment of the slope of the recording

NeYMEYER & Partner GbR, patent attorneys MN

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The gripping element's locking mechanism ensures that when the coil spring is fully tensioned until the individual spring coils touch each other and when a coil spring removed from a spring damper strut is fully relaxed, the gripped spring coil cannot slip off the receiving fork.

By guiding the spring plate through the first gripper element, the guide tube of the spring tensioner is also aligned essentially parallel to the coil spring being held. In the case of coil springs with a large pitch, without a pitch adjustment of the fork-shaped second gripper element, the free end of the coil spring, which lies outside the gripper elements, would move sideways when the coil spring is tensioned, so that, particularly when assembling a coil spring with a large pitch, it is difficult to position it correctly in the second spring plate of the spring damper leg. By adjusting the pitch of the second gripper element to the pitch of the spring coil to be gripped, which it has when the coil spring is accommodated in an unloaded spring damper leg, such lateral movement of the free end of the coil spring is at least minimized, so that assembly of the coil spring is made considerably easier. In addition, any jamming of the second gripper element on the

Neymeyer & Partner GbR, patent attorneys

MN

22 January 1998

Holding element of the guide tube of the spring compressor safely avoided.

The invention is explained in more detail below with reference to the drawing. It shows:

Fig. 1 shows a spring tensioner with two gripper elements in perspective view;

Fig. 2 a spring plate of a motor vehicle with an inclined and offset support bar with a coil spring in a perspective view;

Fig. 3 the gripper element from Fig. 1 in bottom view; Fig. 4 a section II-II from Fig.;

Fig. 5 shows a second embodiment of a gripper element according to the invention with an insert ring;

Fig. 6 is a section IV-IV of Fig. 3.

Fig. 1 shows a spring tensioner 1 with a first gripper element 2 and a second gripper element 3. The first gripper element 2 has an approximately circular ring-shaped receiving section 4, which, as can be seen from Fig. 4, has a substantially L-shaped cross section. The first gripper element 2 is connected via a coupling piece 5 to a holding element 6 of the spring

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Neymeyer & Partner GbR, patent attorneys

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iHfcigeJi-ScJiwenningen (DE) ·* ·* January 22, 1998

tensioner 1, which is firmly arranged at the upper end 7 of a guide tube 8 of the spring tensioner 1.

The second gripper element 3 is provided with a receiving fork 9, which is also positively engaged with a second holding element 11 of the spring tensioner 1 via a coupling piece 10. The second holding element 11 is mounted on the guide tube 8 of the spring tensioner 1 so that it can be moved axially and cannot rotate. The holding elements 6 and 11 are aligned in such a way that the receiving section 4 and the receiving fork 11 of the two gripper elements 2 and 3 are coaxially opposite one another, so that a coil spring 12 to be tensioned, as shown in phantom lines in Fig. 1, is received between the gripper elements 2 and 3 with its longitudinal center axis 13 running parallel to the longitudinal center axis 14 of the guide tube 8. For the longitudinal displacement of the second holding element 11 together with the second gripper element 3, an adjusting spindle is provided which is arranged inside the guide tube 8 (not visible in the drawing) and can be driven in rotation via a drive hexagon 15 located axially outside the guide tube 8.

The ring-shaped receiving section 4 of the first gripper element 2 is mounted on a spring plate 16 of a spring damper leg shown in phantom lines (in the drawing

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Neymeyer & Partner GbR, Patent Attorneys MN

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22 January 1998

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not shown) which serves to accommodate or support the coil spring 12 in the spring damper strut. For fastening to a body of a motor vehicle, the spring plate 16 has four mounting holes 17 which are evenly distributed around the circumference in an approximately circular end wall 18 of the spring plate 16. In its center, the circular end wall 18 of the spring plate 16 has a countersunk mounting plate 19 which is provided with a through hole 20 in its center. The through hole 20 of the mounting plate 19 serves to accommodate the piston rod (not shown in the drawing) of a shock absorber of the spring damper strut and can be screwed tightly to this piston rod.

In such a spring damper leg, the lowest spring coil 21 in the drawing is held by a second lower spring plate of the spring damper leg. In the assembled state of the spring damper leg, the coil spring 12 is between the upper spring plate 16 and the

20. lower spring plate of the spring damper leg under preload so that the coil spring 12 has a shorter length in this preloaded state than in the unloaded state.

To tension the coil spring 12, the receiving fork 9 of the second gripper element 3 is connected to one of the spring

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22 January 1998

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fertilize .22, as shown by way of example in Fig. 1. The receiving fork 9 with its support surface 23 has a pitch which corresponds to the pitch of the spring coil 22 at the pre-tensioned length of the coil spring 12, which it has when the coil spring 12 is accommodated in a fully assembled spring damper leg of a motor vehicle between its upper spring plate 16 and its lower spring plate and the spring damper leg has its maximum length.

Due to this pitch adjustment of the receiving fork 9, the spring coil 22 is guided safely both during the tensioning process of the coil spring 12 and during the release process until it is removed from the spring tensioner 1. In particular, due to this pitch adjustment, only slight eccentric tensioning forces occur with respect to the longitudinal center axis 13 of the coil spring 12, so that tilting of the gripper element 3 with its coupling piece 10 in the holding element 11 is at least largely excluded.

As can be seen from Fig. 1, the spring plate has a circumferential, approximately cylindrical ring wall 24 in the peripheral area axially below its end wall 18, on the lower, spring-side end edge of which a radially outward-directed, approximately perpendicular to the

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A receiving web 25 is arranged that runs along the longitudinal center axis 13. The shape of this receiving web 25 is adapted to the pitch or shape of the uppermost spring coil 26 of the helical spring 12 and has a correspondingly inclined course in the circumferential direction.

Fig. 2 shows this spring plate 4 in perspective, whereby the helical spring 12 shown in phantom lines is held flat by the circumferential receiving web 25. In order to accommodate the uppermost spring coil 26 by the receiving web 25 in this way, the latter is designed to be offset in the circumferential direction in its front area, whereby the spring end 28 is held in the area of the circumferential offset 27 shown in Fig. 2. Due to this offset design of the receiving web 25, it has a support section 29 provided with a slope, the slope of which is at least approximately adapted to the slope of the uppermost spring coil 26. The uppermost spring coil 26 does not necessarily lie against the underside of the receiving web 25 over the entire circumference of the latter. The receiving section 4 with its inner support surface is adapted to this shape of the receiving web 25 with its slope and its circumferential shoulder 27.

For this purpose, the gripper element 2 is shown in Fig. 3 in a bottom view. To clarify the course of the support

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Neymeyer & Partner GbR, patent attorneys MN

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surface, Fig. 4 shows a section II-II from Fig. 3. In
Fig. 3 shows the coupling piece 5 and the receiving section 4 of the gripper element 2. Due to its essentially L-shaped design, the receiving section
4 a radially inwardly directed support ring 30, which is circumferentially surrounded by a radially outer
Ring wall 31 is limited. The lower, spring-side support surface 32 of the support ring 30 has a support section
35, which is aligned with respect to a longitudinal center axis
33 of the receiving section 4 is provided with a slope in the horizontal plane 34 which runs approximately at right angles. This support section 35 extends in the circumferential direction
approximately over a central angle α of about
180°. The remaining support surface of the support surface 32
can, as shown in Fig. 3 and 4,
is arranged in a direction parallel to the horizontal plane 34
Level 36.

The slope of the support section 35 of the support surface
32 corresponds essentially to the slope of the support section 29 of the receiving web 25 of the spring plate 4, so that the gripper element 2 with its receiving section
4 at least in this area of the support section
35 can be placed flat on the receiving web 25 of the spring plate 4 over the central angle α of 180°.
Through this at least partial shape adjustment of the

Support ring 30 with its support surface 32 to the mold

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Neymeyer & Partner GbR, patent attorneys

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By providing the receiving web 25 of the spring plate 4, a centered reception of the entire spring plate 4 in the gripper element 2 or its receiving section 4 is achieved. Furthermore, a centered reception of a spring plate with a flat receiving web on the top is also possible, since the remaining support surface of the support ring is also flat.

It is understood that the shape adaptation of the support surface

32 also over a larger angular range than 180°,

especially over the entire circumference of 360°

of the support ring 30.

Furthermore, to accommodate a spring plate with a larger diameter and, for example, with a flat receiving web, a second support surface 37 is provided which is radially expanded in diameter and offset in the axial direction, the radially outer boundary of which is formed by the annular wall 31 of the receiving section 4. The second support surface 37 is, as can be seen in particular from Fig. 4, offset in the axial direction from the first support surface 32, so that its radially inner boundary forms a centering shoulder 38 for the first support surface 32.

It is understood that the second support surface 37 also conforms to the contour of a with a slope and a

receiving web of a spring plate provided with a catch shoulder

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Neymeyer & Partner GbR, Patent Attorneys

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It is also conceivable that, in a similar design to the second support surface 37, further support surfaces, which are larger in diameter, can be provided for further larger spring plates.

In Figs. 5 and 6, a further embodiment 2/1 of a first gripper element is shown, which also has a coupling piece 5/1 and a receiving section 4/1. Due to its essentially L-shaped design, the receiving section 4/1 forms a radially inward-facing support ring 30/1, which is circumferentially delimited by a radially outer ring wall 31/1. An insert ring 39 is inserted in a fitting and replaceable manner into the receiving section 4/1 with its support ring 30/1 and its ring wall 31/1, which also has an approximately L-shaped cross-sectional shape with an approximately cylindrical ring web wall 41 and a circumferential, radially inward-facing support ring 40. The support ring 40 is provided with a lower, spring-side support surface 32/1, which has a support section 35/1. The support section 35/1 is provided with a slope with respect to a horizontal plane 34/1 that runs approximately at right angles to the longitudinal center axis 33/1 of the receiving section 4/1. This support section 35/1 extends in the circumferential direction approximately over a central angle α of approximately 180°. The remaining support surface

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Neymever & Partner GbR, patent attorneys

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The support surface 32/1 can, as shown by way of example in Figs. 5 and 6, lie in a plane 36/1 arranged parallel to the horizontal plane 34/1.

Thus, the gripper element 2/1 of the embodiment according to Fig. 5 and 6 differs from the gripper element 2 from Fig. 2 and 3 only by the insert ring 39, which has the shape-adapted support surface 32/1 for receiving the spring plate 4. The design of the support surface 32/1 corresponds to the design of the support surface 32 and accordingly also has the same advantages.

Furthermore, to accommodate a spring plate with a larger diameter and, for example, with a flat receiving web, a second support surface 37/1 is provided which is radially expanded in diameter and offset in the axial direction, the radially outer boundary of which is formed by the ring web wall 41. The second support surface 37/1 is also offset in the axial direction compared to the first support surface 32/1, so that its radially inner boundary forms a centering shoulder 38/1 for the first support surface 32/1.

It goes without saying that this second support surface 37/1 can also be adapted to the contour of a receiving web of a spring plate provided with a slope and a circumferential shoulder. It is also conceivable that

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&Idigr;8052 f «lingwT-Sehwenningen (DE) 22 January 1998

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in a similar design to the second support surface 37/1, further support surfaces, which are larger in diameter, can be provided for further larger spring plates.

The inventive design of the two gripper elements 2, 2/1 and 3 provides a spring tensioner with which coil springs with a large pitch can be tensioned without there being a risk of the coil spring slipping or bulging during the tensioning process in the area between the two gripper elements 2, 2/1 and 3.

This is achieved by the shape-adapted design of the support surface 32, 32/1 of the support ring 30 or the support ring 40 of the gripper element 2 or 2/1, as well as by the pitch adjustment of the receiving fork 9 of the gripper element 3 to the pitch of a coil spring 12 accommodated between two spring plates, when this is inserted in an unloaded, i.e. axially non-shortened, spring damper leg. In addition, the pitch adjustment of the receiving fork 9 of the second gripper element 3 largely prevents the lower spring end 21 of the coil spring 12 from moving sideways, so that it can be easily placed on the lower spring plate of the spring damper leg during assembly.

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Neymeyer & Partner GbR, patent attorneys

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can be aligned and is recorded correctly aligned.

Claims (5)

1. Spring tensioner for tensioning a coil spring which between an upper and a lower spring plate of a spring damper strut of motor vehicles under Preload is taken up, consisting of a first and a second gripper element, which are coaxial to each other on a guide tube of the spring tensioner
are arranged and in the axial direction of the guide tube res are displaceable relative to each other by means of an actuator of the guide tube, wherein the first
Gripper element for holding the spring plate approximately
is circular in shape and the second
The gripper element is approximately fork-shaped and can be brought into engagement with a spring coil of the coil spring to tension the coil spring,
characterized, that the first gripper element (2, 2/1) has at least one support surface (32, 32/1) adapted to the contour of the upper spring plate (4), so that during the clamping process the upper spring plate (4) is supported at least over a NEYMEYER& Partner GbR, Patent Attorneys JSOS; 7iily^«n*-§ühwenningen (DE) .1. ..* *·· ^? 22 January 1998 Support angle of at least approximately 180° lies flat in the gripper element (2, 2/1). 2. Spring tensioner according to claim 1, characterized in that the support surface (32) of the first gripper element (2) is an integral part of the gripper element (2). 3. Spring tensioner according to claim 1, characterized in that the support surface (32/1) of the first gripper element (2/1) is part of a separate insert ring (39) which can be inserted into the first gripper element (2/1). 4. Spring tensioner according to one of claims 1 to 3, characterized in that several approximately ring-shaped support surfaces (32, 37 or 32/1, 37/1) with different diameters are provided, which are arranged concentrically to one another and have differently shaped surfaces in the direction of a longitudinal center axis (33, 33/1) running approximately at right angles to the support surfaces (32, 37 or 32/1, 37/1) for adaptation to differently designed spring plates (4), and that the larger support surface (37, 37/1) in each case has a circumferential centering shoulder (38, 38/1) for the adjacent smaller support surface (32, 32/1) 25 forms. Neymeyer & Partner GbR, Patent Attorneys MN J J8O5; Tijliifeftn*-5<ihwenningen (DE) .* .&Sgr;. ..**··* 22 January 1998 5. Spring tensioner according to one of claims 1 to 4, characterized in that the second gripping element (3) is approximately fork-shaped and has a pitch which corresponds approximately to the pitch of a spring coil to be gripped by the second gripper element (3) (22) which it has when the coil spring (12) is clamped between the two spring plates (4) of a spring damper leg when the spring damper leg assumes its maximum unloaded length.