EP0702661A1

EP0702661A1 - Telescopic boom

Info

Publication number: EP0702661A1
Application number: EP94920945A
Authority: EP
Inventors: Ernst Kaspar
Original assignee: EC Engineering and Consulting Spezialmaschinen GmbH
Current assignee: Compact Truck AG
Priority date: 1993-06-16
Filing date: 1994-06-16
Publication date: 1996-03-27
Anticipated expiration: 2014-06-16
Also published as: DE9308993U1; CN1127497A; EP0702661B1; WO1994029212A1; JP2828779B2; DE59404835D1; JPH09501384A

Abstract

The invention pertains to a telescopic boom with at least one outer structure (14) and at least one inner structure (16), each of which is designed as a hollow section with upper flange (1) and lower flange (2), the upper flange (1) having a half-basket profile with two rounded edges (Ri, Ra) to which the lower flange (2) is joined with a liner of an essentially U-shaped profile, and each structure being mounted on the adjoining structure with a front and a back bearing (3, 4). To achieve a stable bearing of the structures and a great usable extension length with this boom under high force level, the invention proposes that the front bearing (3) has a slide element (10) in the area between the lower flanges (2) only in the region of the curve, and the back bearing (4) has a separate plain bearing half liner (12) in the area between the upper flanges (1) only in the region of each rounded corner (Ri, Ra).

Description

Telescopic boom

The invention relates to a telescopic boom with at least one outer slide and at least one inner slide, each of which is designed as a hollow profile with an upper chord and lower chord, the upper chord having a half-box shape in cross section with two corner rounds, to which the Connects lower chord with a shell which is essentially U-shaped in cross section, and each pusher is mounted on the adjacent pusher via a front and a rear bearing point.

Booms of this type are known in practice, for example from mobile cranes. In this case, a load is attached to the front end of an extended inner drawer, so that the inner slide with its lower flange loads the front end portion of the lower flange of the outer drawer . At the same time, the rear end of the inner drawer with its top strap loads the top strap of the outer drawer. In the context of this invention, “front” denotes the direction to the load-bearing free end of the boom and “rear” denotes the direction to the end opposite the free boom end.

As a result of the high forces to be transmitted, special care must be taken to design the front and rear bearing parts. In addition to secure storage, these are also intended to counteract undesirable deformations of the profile cross sections. The aim here is usually for all-round mounting of sliding elements at the front and rear bearing points. The sliding elements are each fixed to one of the sliders on a flat, laterally bordered bearing block and are supported on the opposite slider on the opposite side. To absorb the forces acting on the sliding elements and the bearing blocks, reinforcing support means in the form of collars are necessary. The collars of the inner pupils are in generally formed continuously over the cross-sectional shape of the pusher and together form the border for the sliding elements, while the collars of the front bearing points are generally attached to the outside of the pusher and made of solid material with a dimension of 150 to 300 mm in the longitudinal direction of the boom consist. The collars thus reduce the usable extension length of the drawer concerned. As shown in FIG. 6 (prior art), the inner pushers cannot be moved completely into one another, since they are hindered by the inner collars. The same occurs analogously in the area of the front bearing with the outer collars.

DE-OS 1531174 proposes a roller bearing for telescopic booms with a polygonal cross section. In order to absorb the ring stresses that occur during loading, an outer roller is assigned to each corner of the lower flange and an inner roller to each corner of the upper flange. Unfortunately, the outer and inner rollers each interfere when the pushers are moved into one another, so that the usable extension length of the pushers is reduced by at least the sum of the diameters of the rollers arranged next to one another. In addition, the inner rollers take up a lot of space in the hollow profile cross section of the inner drawer, so that there is little space available for the telescopic cylinder unit arranged therein for extending the boom.

The invention has for its object to provide a telescopic boom of the type mentioned, which can absorb high forces and is characterized by a safe storage of the pushers and a large usable extension length.

This object is achieved in that the front bearing in the area between the lower chords has a sliding element only in the area of the curvature, and the rear bearing in the area between the upper chords only has a separate plain bearing shell in the area of each corner round.

As a result of this mounting, the forces between two adjacent thrust pieces are only transmitted via rounded areas which are considerably stiffer than the straight surface of the bearing blocks which is customary in the prior art. This prevents bulging of the surfaces and the deformation of the profile cross section. The function of the collar can essentially be restricted to preventing the drawer from expanding at its end. Since the collar no longer has to absorb the supporting forces to the full extent, it can be made considerably shorter in the longitudinal direction of the pushers. In practice, the collar can be reduced to a length of approx. 50 mm. This means that the individual pushers, as shown in FIG. 5, can be moved into each other much further, so that a larger usable boom length is available.

On the other hand, the sliding element and the plain bearing shells can be made much thinner. While thicknesses of 40 to 50 mm are still necessary in the prior art, the thickness can be reduced to less than 20 mm in the solution according to the invention. This means that there is more space available in an outer slide for additional inner slide, which yield a gain in the usable boom length. With the storage according to the invention, 7 pushers can be pushed into one another without any problems, the cross section of the outermost drawer not exceeding the outer cross section of conventional telescopic booms. With the bearings according to the prior art, it was previously only possible to arrange a maximum of 5 slides one inside the other.

In addition, the tolerances of the sliding element and the slide bearing shells can be adapted to the corner rounds and the lower flange shape, respectively, almost exactly. The storage leaves little Deformations of the straight areas of the cross section, while the rounded areas guarantee the exact positioning of the pushers in one another. It is therefore also possible to dispense with additional tolerance compensation elements, as were usually necessary in the prior art.

The sliding element and the sliding bearing shells advantageously center themselves on the rounded areas. It is therefore not necessary to define them in the circumferential direction of the cross section.

Particularly advantageously, the rear bearing point in the area between the lower chords has at least one shell-shaped sliding element which extends at least in regions in each of the curved sides of the lower chords adjoining the upper chords. This arrangement is particularly favorable for absorbing lateral forces which arise, for example, when a mobile crane is turned. The cup-shaped sliding element prevents torsion of the cross-section of the boom.

It is proposed that the rear bearing point have two separate sliding jaw elements in the area between the lower belts, one of which is arranged in each of the curved sides of the lower belts adjoining the upper belts. The shell-shaped sliding element is thus divided into two separate sliding jaw elements, each of which absorbs the torsional forces. There is no need for support in the lower U-point of the lower flange. This simplifies the manufacture of the profile cross sections in this area, since precise tolerance information can be dispensed with.

As a variant of the invention, the front bearing point in the area between the top chords has a separate plain bearing shell only in the area of each corner round. These additional Sliding bearing shells on the corner rounds prevent the cross-sections from twisting.

The slide jaw element and slide bearing shells of the rear bearing point are preferably fixed to the inner slide.

In a special way, the sliding element (s) and the sliding bearing shells of the front bearing point can be fixed on the outer slide.

As a preferred embodiment, the radial distance between the inner and outer pushers is greater in the area of the corner rounds than in the straight areas of the upper chord. The plain bearing shells can thus be made somewhat thicker in the area of the corner rounds, so that they can transmit greater forces. The remaining space in the straight areas is minimized to save space.

The center point of the outer corner round and the center point of the inner corner round of the front bearing point and / or the rear bearing point can possibly be arranged at a distance from one another, the center point of the outer corner round being arranged closer to the corner rounds than the center point of the inner corner round is. This creates an increase in the space for the plain bearing shells in the rounded area, the distance in the subsequent straight areas being able to be kept small.

Preferably, the plain bearing shells of the corners and / or the sliding elements in the lower chord area of the front and / or rear bearing point extend beyond the curved areas into the straight areas of the upper chords, the plain bearing shells or the sliding elements on the side of the relative to them Moving pushers only rest against this pushing device in the curved area. The support of the plain bearing shells or the sliding elements is thus at relatively moving Schübling limited to the stable, curved areas. This prevents jamming of the pushers since the end of the force introduction zone (curvature) does not meet the end edge of the slide bearing shell. On the slide, on which the sliding element is fixed, for example, it extends into the straight region, so that it automatically positions itself in the circumferential direction of the profile cross section at the transition from the curved and straight region.

The sliding bearing shells in the straight upper chord region and / or the sliding elements in the lower chord region on the side of the relative movement are advantageously spaced apart from the slide at an angle α from the straight side. This sloping start-up zone prevents particularly well the jamming of the pupils.

In a special way, the outer slide in the area of the front bearing point can have a front collar and the inner slide in the area of the rear bearing point can have a rear collar, which serve as axial contact of the sliding element, slide bearing shells or sliding jaw elements. The collars reinforce the profile and prevent the pushers from expanding or pressing in at their ends, the sliding bodies being simultaneously positioned on the collars.

It is proposed that the sheet thickness of the front and rear collars is 1.2 to 2.5 times the sheet thickness of the respective boom profile.

As a variant of the invention, the sheet thickness of the upper chord is different from the sheet thickness of the lower chord.

Particularly advantageously, the U-shaped shell of the lower flange has two round shells which are spaced apart from one another and which are connected to one another via a straight web arranged between them. This particular profile cross The U-shape has proven to be particularly suitable because it has a large moment of resistance to bending. Here, too, the transverse forces are introduced according to the invention into the curved zones of the profile, namely via the round shells into the lower flange, so that the entire profile is very resistant to dents due to the shell effect of the curved regions. The membrane effect of a shell is used.

The length of the web preferably corresponds to a ratio of 1: 3 to the profile width. In this sense, the profile width is the distance between the straight sides between the top flange and bottom flange of a drawer.

It is proposed that the front bearing point have a separate sliding element in the area between the lower chords in the area of each round shell. As a result, even in the lower chord area of the front bearing point, the forces are transmitted only via the rounded areas. Due to the separate, divided arrangement of the sliding elements, tolerances in the width of the individual sliders can be compensated for well. Furthermore, there are no moments in the transition area to the straight sides of the upper chord or to the straight web, since the circumferential tensions are introduced tangentially.

Conveniently, the radial distance between the inner and outer plug in the area of the round shells can be greater than in the straight areas of the lower flange.

As a preferred embodiment, the center of the outer round shell and the center of the inner round shell of the front bearing point are arranged spaced apart from one another, the center of the outer round shell being arranged closer to the round shells than the center of the inner round shell. The ratio of profile width to profile height is preferably approximately 1: 1.15 to 1: 1.4.

In a special way, the ratio of the length of the straight side between a corner round of the upper flange and the subsequent curved region of the lower flange to the profile height can be approximately 1: 1.6 to 1: 2.

The invention is explained in more detail below on the basis of exemplary embodiments and with reference to the drawing. In this shows:

1 shows a simplified, partially sectioned representation of a section of an outer drawer in which an inner slide is partially accommodated,

FIG. 2 shows a cross section along the line A-A in FIG. 1,

3 shows a cross section along the line B-B in FIG. 1,

4 shows an enlarged partial cross section along the line B-B in FIG. 1 with a sliding element in the corner round region,

5 shows a simplified sectional view of the rear ends of three nested pushers of a boom according to the invention,

Fig. 6 is a simplified sectional view of three nested sliders with wide rear collars of a boom according to the prior art and

7 shows a cross section through the front bearing point of a boom according to the invention with eight pushbuttons, the lower chords of which have two spaced-apart round shells. 1 to 3, an outer slide 14 and an inner slide 16 are shown. The inner slide 16 is located with a partial length inside a front section of the outer slide 14. Each slide consists of two bent sheet metal half-shells which are connected to one another by longitudinal weld seams. The top chords 1 of each slide have a U-shaped shape with quarter-round corner curves R. In FIGS. 2 and 3, the two corner curves of the inner drawer 16 are denoted by Ri, and the two corner curves of the outer drawer 14 are denoted by Ra. The corner curves extend over 60 to 90o.

The lower chords 2 of the two slugs 14 and 16 have a semicircular shape with a radius which is equal to half the width (b) of the associated upper chord. It goes without saying that the radius of the lower flange 2 of the inner drawer 16 is accordingly smaller than the radius of the lower flange of the outer drawer 16. The upper and lower belts can have different sheet thicknesses.

The welded upper and lower chords have a front collar 7 at their longitudinal ends and a rear collar 8 in the form of welded-on metal sheets at their rear ends. These collars are corrosion-resistant and serve as bearing points. Each lower flange 2 is assigned a front bearing 3 and each upper flange 1 a rear bearing 4.

The two collars 7 and 8 also form a stop for the sliding element 10 and the slide bearing shells 12 made of plastic, which are provided at least in the area of the bearing points between the inner slide and the outer slide. A sliding element 10 made of plastic, preferably made of polyamide, is provided in the area of each bearing point 3 associated with the lower flange, the shape of which is semicircular. corresponds to the gap between the lower flange of the inner thrust member 16 and the lower flange of the outer drawer 14. Furthermore, in the area of each bearing point 4 assigned to the upper flange 1, bearing bushes 12 carrying at least two intermediate spaces between the inner upper flange and the outer upper flange are provided in the region of the two corner curves Ri and Ra, as shown in FIG. 3. The semicircular sliding element 10 advantageously extends up to the horizontal line labeled C in FIGS. 2 and 3.

The sliding element 10 and the sliding bearing shells 12 are each fixed to the outer slide 14.

The interaction of the two bearing points 3 and 4 enables a transfer of transverse forces and bending moments from an inner slide to the adjacent outer slide.

If, as shown in FIG. 1, a force F acts on the inner slide 16, this causes a moment M, which in turn causes transverse forces Qv and Qh. The shear force Qv deforms the lower flange of the inner drawer oval. The transverse force Qv is introduced into the outer slide 14 via the sliding element 10, whereupon its cross section is also deformed oval. In particular, the cross section becomes longer in the vertical direction and shorter in the horizontal direction. This shortening in the transverse direction leads to advantageous stabilization of the bearing point 3 by a barrel eye effect as a result of the pressure exerted on the inner slide. Furthermore, bulging is prevented by the large-area contact mediated by the lubricant element 10. The undesired bulging is also prevented by the fact that the transverse force Qv acts on the semicircular shaped lower flange, so that the membrane effect of a shell can be exploited. As a result, the sheet thickness may be small, which leads to a reduction in the dead weight. The rear bearing force Qh loads the inner surface of the outer drawer 14 in the area of the rear bearing point 4. As shown in FIG. 3, in the area of the rear bearing point 4 the two inner corner rounding areas R 1 with the help of the two slide bearing shells 12 with the two outer corner rounding areas Ra connected, the inner corner areas belonging to the inner slide 16 and the outer corner rounded areas belonging to the outer slide. It should be noted at this rear bearing 4 that the plain bearing shells 12 are not supported on a separate collar, as in the prior art, but are supported by the curved plate of the inner drawer 16. As a result, the disk effect of the flanges is simultaneously used when introducing the load. From this in turn it follows that in the telescopic boom according to the invention the width of the slide bearing shells 12 and the sliding element 10 (ie their dimension in the longitudinal direction of the boom) is independent of the width of the assigned collar 8. As already mentioned, this construction again results an increase in usable boom length.

The sheet thickness of the front collar 7 as well as the sheet thickness of the rear collar 8 is preferably 1.2 to 2.5 times the sheet thickness of the sheet used for the respective cantilever profile.

The front collar 7 can in the spaces between the outer corner curves Ra and the inner corner curves Ri each be assigned a slide bearing shell 18 made of plastic, as shown in FIG. 2. Instead of the two slide bearing shells 18 shown in FIG. 2, only a single slide element can be provided. The slide bearing shells 18 must be designed and arranged such that the inner slide 16 is prevented from tipping inside the outer drawer 14. The bearing point assigned to the slide bearing shells 18 is not permanently subjected to forces.

In the area of the rear collar 8, specifically in the lower flange area thereof, as shown in FIG. 3, sliding shoe elements 15 made of plastic can be provided. These sliding jaw elements 15 are arranged between the semicircular lower flange of the inner drawer 16 and the semicircular lower flange of the outer drawer 14. Advantageously, they extend with their upper ends to the horizontal line C. Instead of the two-part design of the sliding jaw elements 15 shown in FIG. 3, they can also be formed in one piece. Basically, slide jaw elements 15 are to be designed and arranged such that the inner slide 16 does not tip inside the outer drawer 16, since the latter slide elements are particularly stressed when a lateral force or a transverse force component acts on the inner slide.

The previously discussed plain bearing shells 18 (Fig. 2) are only in the maximum telescoped state, i.e. only with a minimal clamping length of the inner drawer, loaded to support it against lateral deflection (tipping).

4 shows a slide bearing shell 12, which is shown between two corner rounds Ri, Ra of the upper chords 1 at the rear end of an inner drawer 16. In the area of the corner rounds Ri, Ra, the distance between the two upper chords 1 is greater than in the straight areas of the upper chord 1. The corner rounds Ri, Ra have centers Ma, Mi spaced apart from one another, the center point Ma being closer to the corner round Ra the slide bearing shell 12 or the corner round Ri, Ra is arranged. The figure shows the center point Ma in each case by two radii ra drawn in and, analogously, the center point Mi by the two radii ri. The slide bearing shell 12 is fixed to the inner slide 16 so that it performs a relative movement relative to the corner round Ra of the outer drawer. The slide bearing shell 12 extends into the straight areas adjoining the corner rounds Ri, Ra, it also abutting the inner slide 16 in the straight area. With regard to the outer thrust member 14, the slide bearing shell 12 withdraws from the outer thrust member 14 at the transitions to the straight regions at an angle α. Accordingly, it lies against the outer slide 14 only in the area of the corner round Ra. Analogously to FIG. 4, the slide bearing shells 18 of the front end are designed. In this case, the plain bearing shells 18 also abut the outer slide 14 in the straight region and recede from the upper flange 1 in the straight regions of the inner drawer 16 at an angle α.

In Fig. 5 a collapsed boom with three sliders is shown. A sectional view of the rear slide bearing shells 12 is placed in each case in the vertical section. They rest on one side on the narrow rear collar 8 and are bordered on the other side by an edge 20. The edge 20 is limited over the circumference to the area of the slide bearing shells 12. In the inserted state shown, the slide bearing shells 12 of the neighboring pushbuttons partially overlap and can therefore be pushed very far into one another.

In Fig. 6 three Schüblinge are shown in the retracted state according to a bearing arrangement of the prior art. Here, the pushers are supported one inside the other by an all-round bearing arrangement, the bearing elements 30 each being received in a half-box-shaped bearing block 31 which is offset to the inside with respect to the associated pushing member. The border of the bearing block 31 is formed in each case by two collars 32 which are continuous over the cross section of the drawer. As can be seen from Fig. 6, the continuous collar 32, which are necessary for stability, a further insertion of the inner slider 16, so that the rear ends of the slider 16 must be arranged side by side. In addition, it is shown in the drawing that the bearing elements 30 are substantially thicker in the radial direction than the sliding elements 12 according to the invention (FIG. 5).

FIG. 7 shows a telescopic boom according to the invention with eight pushers, in which the U-shaped shell of each lower flange 2 is formed from two quarter-circular round shells 33 arranged at a distance from one another. A straight web 34 is arranged between the round shells 33 and extends parallel to the straight region of the upper chord 1 between the corner rounds Ri, Ra.

A substantially quarter-circle sliding element 10 is arranged between the round shells 33 of two adjacent sliders. The sliding element 10 is adapted to the respective shape of the rounded regions of the round shells 33. The sliding elements 10 are each fixed to their outer slide 14 and extend on this side in some areas into the straight web 34 or the straight side 35 between the lower flange 2 and the upper flange 1. On the side of the inner drawer 16, the sliding elements 10 rest only in the curved region of the round shells 33. In the straight region, the sliding elements 10 are designed analogously to the ends of the sliding bearing shells 12 shown in FIG. 4. The sliding elements on the side of the inner drawer 15, starting from the rounded area in an oblique outlet zone, recede at an angle α from the inner slide.

Of course, the rear bearing 4 in the lower flange area 2 can also be formed as shown in FIG. 7. In this case, the sliding jaw elements 15 are designed like the round shells 33. It goes without saying that in the cross section shown in FIG. 7 in the upper chord region 1, the same arrangement of the slide bearing shells 18 in the region of the corner rounds Ri, Ra can be selected as in the exemplary embodiments described in the remaining figures.

Claims

Protection claims

1. Telescopic boom with at least one outer slide (14) and at least one inner slide (16), each of which is designed as a hollow profile with a top flange (1) and bottom flange (2), the top flange (1) having a half-box shape in cross section with two Has corner rounds (Ri, Ra) to which the lower flange (2) adjoins with a shell which is essentially U-shaped in cross-section, and each slide on the adjacent slide via a front and a rear bearing point (3, 4 ) is mounted, characterized in that the front bearing (3) in the area between the lower chords (2) has a sliding element (10) only in the area of the curvature, and the rear bearing (4) in the area between the upper chords (1) has a separate plain bearing shell (12) only in the area of each corner round (Ri, Ra).

2. Boom according to claim 1, characterized in that the rear bearing (4) in the area between the lower chords (2) has at least one cup-shaped sliding element (15), which is at least area-wise in each of the upper chords ( 1) then extends the curved sides of the lower chords (2).

3. Boom according to claim 1 or 2, characterized gekennzeich¬ net that the rear bearing (4) has two separate sliding jaw elements (15) in the area between the lower belts (2), one in each of which the upper chords (1) adjoining curved sides of the lower chords (2) are arranged.

4. Boom according to one of the preceding claims, characterized in that the front bearing point (3) in the area between the upper chords (1) only in the area each corner round (Ri, Ra) has a separate slide bearing shell (18).

5. Boom according to one of the preceding claims, characterized in that the slide jaw elements (15) and slide bearing shells (12) of the rear bearing point (4) are fixed to the inner slide (16).

6. Boom according to one of the preceding claims, characterized in that the / the sliding element (s) (10) and the slide bearing shells (18) of the front bearing point (3) on the outer slide (14) are fixed.

7. Boom according to one of the preceding claims, characterized in that the radial distance between the inner and outer Schübling (14, 16) in the area of the corner rounds (Ri, Ra) is greater than in the straight areas of the upper flange (1).

8. Boom according to one of the preceding claims, characterized in that the center point (Ma) of the outer corner round (Ra) and the center point (Mi) of the inner corner round (Ri) of the front bearing point (3) and / or the rear bearing point (4th ) are arranged spaced from one another, the center (Ma) of the outer corner round (Ra) being closer to the corner rounds (Ri, Ra) than the center (Mi) of the inner corner round (Ri).

9. Boom according to one of the preceding claims, characterized in that the slide bearing shells (12, 18) of the corner rounds (Ri, Ra) and / or the Gleitele¬ elements (10, 15) in the lower chord region (2) of the front and / or rear bearing (3, 4) beyond the curved areas into the straight areas, the sliding elements (10, 15) or the plain bearing shells (12, 18) on the side of the relative to them moving pushers only touch this pushing device in the curved area.

10. A boom according to claim 9, characterized in that the slide bearing shells (12, 18) in the straight upper belt area (1) and / or the sliding elements (10, 15) in the lower belt area (2) on the side of the relative movement of the Schübling spaced at an angle (α) from the straight side.

11. Boom according to one of the preceding claims, characterized in that the outer slide (16) in the region of the front bearing (3) has a front collar (7) and the inner slide (14) in the region of the rear bearing (4) has a rear Collar (8) has, which serve as an axial contact of the sliding element (10), plain bearing shells (12, 18) and sliding jaw elements (15).

12. Boom according to one of the preceding claims, characterized in that the sheet thickness of the front and rear collars (7, 8) is 1.2 to 2.5 times the sheet thickness of the respective boom profile.

13. Boom according to one of the preceding claims, characterized in that the sheet thickness of the upper belt (1) is different from the sheet thickness of the lower belt (2).

14. Boom according to one of the preceding claims, characterized in that the U-shaped shell of the lower flange (2) has two spaced-apart round shells (33) which are connected to one another via a straight web (34) arranged between them.

15. Boom according to claim 14, characterized in that the length of the web (34) to the profile width corresponds approximately to a ratio of 1: 3.

16. Boom according to claim 14 or 15, characterized gekenn¬ characterized in that the front bearing (3) in the area between the lower chords (2) each in the region of each round shell (33) has a separate sliding element (10).

17. Boom according to one of claims 14 to 16, characterized in that the radial distance between the inner and outer pushers (14, 16) in the region of the round shells (33) is greater than in the straight regions (34) of the lower flange ( 2).

18. Boom according to one of claims 14 to 17, characterized in that the center point of the outer round shell (33) and the center point of the inner round shell (33) of the front bearing point (3) are arranged at a distance from one another, the center point the outer round shell (33) is arranged closer to the round shells (33) than the center of the inner round shell (33).

19. Boom according to one of the preceding claims, characterized in that the ratio of profile width to profile height is approximately 1: 1.15 to 1: 1.4.

20. Boom according to one of the preceding claims, characterized in that the ratio of the length of the straight side (35) between a corner round (Ri, Ra) of the upper flange (1) and the subsequent curved region (33) of the lower flange (2) to the profile height is about 1: 1.6 to 1: 2.