CN205153239U - Formula truss makes up mandrel on an empty stomach - Google Patents

Abstract

The utility model discloses a formula truss makes up mandrel on an empty stomach, middle support frame more than upper cover frame, lower cover frame and one deck, the upper cover frame is the truss structure, and the lower cover frame is the truss structure, and middle support frame establishes between upper cover frame and lower cover frame, be equipped with connection structure between upper cover frame and middle support frame, connection structure under being equipped with between lower cover frame and middle support frame. The utility model aims at providing an each side to the formula truss makes up mandrel on an empty stomach that mechanical properties is good, this mandrel gets off each partial dismounting when the transportation for the combination formula, has saved transportation space and cost of transportation, can be quick when the construction couple together each part, the installation with dismantle all very convenient.

Description

A kind of open web type truss composite core formwork

Technical field

The utility model relates to the core used in body of wall or floor in building.

Background technology

In the past, China's major part building is all reinforced concrete structure, and the building consumptive material of this structure is large, and weight very, and particularly for floor, middle part is generally unsettled, and therefore, the intensity of floor is low.For this reason, country advocates and adopts the building of cast-in-situ hollow floor plate technology realization to floor, like this, not only can reduce consumptive material, and can alleviate the weight of floor.

At present, the technology of cast-in-situ hollow floor plate is adopted mainly: first build template, then set a layer reinforcing bar on template upper berth, core fixed by lower floor's reinforcing bar, then top reinforcement is set on core, last fluid concrete.

But existing core is mostly hollow-core construction, be the making construction method disclosing a kind of cast-in-situ reinforced concrete hollow floor in the patent document of 2005.7.27 as being 200510020286.0 publication date at application number, a kind of inflatable core with being vented is disclosed in this patent document, namely when the concrete is poured, inflate to core, after construction completes, then release the gas in core, and core is extracted out, although this structure can alleviate the weight of floor, but be hollow-core construction because the inflation of this core is rear, when fluid concrete, the phenomenon damaged is there is once core, constructor cannot search fast, and concrete can be made to enter in core, concrete is caused to surpass the phenomenon of filling, and the core opposing of this structure from the hard breakdown that brings in construction and impact failure performance also poor, in addition, when fluid concrete, need to vibrate, gas is discharged, stop hollowing phenomenon, but in the process of vibrating, easily damage core, once core is damaged, gas then in core can leak, and this process concrete does not also solidify, and therefore, easily occurs the phenomenon of subsiding at core place.

For solving the problems of the technologies described above; name is called in the patent document of the lightweight solid-web type core being applied to cast-in-place concrete hollow floor slab and discloses a kind of core mold structure; it comprises solid formula light-weight foam inner core; topping is wrapped with at solid formula light-weight foam inner core; but this core volume in transportation is large, and cost of transportation is high.

In order to solve the problem of cost of transportation, be 200810210088.4 applyings date be 2008.8.20 publication date in Chinese Patent Application No. be disclose a kind of shuttering member in the patent document of 2010.2.24, and specifically disclose and comprise basin-shaped molds, basin-shaped molds is overall component, the basin mouth of two basin-shaped molds fastens relatively, and the fastening position of two relative basin mouths is engaged by ridge keel and forms overall shuttering member.In the structure shown here, basin-shaped molds and ridge keel can be dismantled, therefore, transport space can be reduced, but, when the shaping cassette ceiling of use shuttering member, because concrete is coated on shuttering member completely, therefore, before concrete does not solidify completely, basin-shaped molds needs to bear larger vertical force and lateral force, and due to shuttering member be hollow-core construction, basin-shaped molds is all hanging shape except edge, the cross section of basin-shaped molds is similar platy structure simultaneously, therefore, the stress performance of basin-shaped molds is bad, the phenomenon easily deformed, once shuttering member distortion, the phenomenon of subsiding then is there will be at shuttering member place, the cast of cassette ceiling can be affected.

Be 200710200786.1 applyings date be 2007.6.7 publication date in Chinese Patent Application No. be disclose a kind of concrete pore-creating core in the patent document of 2008.12.10, and specifically disclose in the middle part of basin-shaped components and be provided with oviduct, the oviduct docking of upper and lower basin-shaped components, when fluid concrete, concrete flows into through oviduct, improve the globality of floor, although oviduct can improve stress performance vertical in the middle part of concrete pore-creating core, but, basin-shaped components is shell structure, consumptive material is many, need by particular manufacturing craft shaping, cost is high, and, when fluid concrete, concrete has extruding force that is vertical and side direction to concrete pore-creating core, concrete pore-creating core is easily out of shape.

Be 200610108872.5 applyings date be 2006.8.17 publication date in China Patent No. be disclose a kind of hollow mould in the patent document of 2007.5.2, comprise truss and the soft hollow mould of flexibility, this truss has good supporting role to hollow mould, when fluid concrete, the transmission of energy realizable force, but, see manual and the Figure of description of this patent document, truss is mainly arranged on side, flexible soft hollow mould is only at the top of hollow fetal membrane and bottom, without any truss support, therefore, when fluid concrete, therefore easily there is the phenomenon of subsiding in concrete under self gravitation effect at the top of hollow mould, even there will be the phenomenon of tearing flexible soft hollow mould, there is the insecure situation of hollow mould load, and once there is the phenomenon of subsiding, need to supplement concrete to the part of subsiding, the amount of concrete of cast is caused to increase, also allow the weight of floor or body of wall increase simultaneously, if there is the phenomenon that the soft hollow mould of flexibility is torn, concrete then can enter in hollow mould, be difficult to form cassette ceiling or body of wall, and concrete consumption can be increased.

Summary of the invention

The purpose of this utility model is to provide a kind of open web type truss composite core formwork good in all directions mechanical property, this core is knockdown, when transporting, various piece is disassembled, save transport space and cost of transportation, fast various piece can be coupled together when constructing, mounting and dismounting all very convenient.

For achieving the above object, a kind of open web type truss composite core formwork, comprises the intermediate support framework of more than upper cover framework, lower cover framework and one deck; It is characterized in that: upper cover framework is trussed construction, lower cover framework is trussed construction, and intermediate support framework is located between upper cover framework and lower cover framework; Between upper cover framework and intermediate support framework, be provided with syndeton, between lower cover framework and intermediate support framework, be provided with lower syndeton.

When utilizing mandrel molding cassette ceiling, from the stressed upper analysis of core, the top of core and bottom are mainly born from concrete lateral pressure, the pressure of this concrete lateral pressure and core top and bottom is mainly born in the middle part of core, because of the gravity of concrete self, lateral pressure is much larger than lateral pressure, in the utility model, upper cover framework and lower cover framework are arranged to trussed construction, the resistance to compression improving upper cover framework and lower cover framework can reached, bending resistance, make the mechanical property of core better, because core of the present utility model is by upper cover framework, lower cover framework and intermediate support framework composition, when transporting, core is dismantled, and allow multiple upper cover framework, multiple lower cover framework overlaps, greatly can reduce transport space, reduce cost of transportation, at the scene, in utilization, core fits together by syndeton and lower syndeton, the object of Fast Installation can be realized, be more convenient for operating.

Further, described upper cover framework comprises the upper cover outside framework that surrounded by roof side rail truss and above horizontally draws truss, above horizontally draws truss to be positioned at upper cover outside framework and is connected with upper cover outside framework; Described lower cover framework comprises the lower cover outside framework that surrounded by lower-edge beam truss and bottom rail draws truss, and bottom rail is drawn truss to be positioned at lower cover outside framework and is connected with lower cover outside framework; Described intermediate support framework comprises cramp bar and is connected to the drag link between adjacent cramp bar.

For intermediate support framework, because lateral pressure is relatively little, like this, as long as the pressure from upper cover framework and lower cover framework can be born, therefore, as long as intermediate support framework be arranged to by cramp bar and be connected to the requirement that structure that the drag link between adjacent cramp bar forms can reach use, alleviate the weight of whole core, also reach the object of saving material simultaneously; In addition, for upper and lower covers framework, in utilization horizontal draw truss and bottom rail draw truss can allow the top of core and bottom stressed more even, be not easy the phenomenon occurring at core place subsiding.

Further, roof side rail truss comprises roof side rail cross bar and the roof side rail pull bar of more than two, is connected with the roof side rail pull bar of more than two between adjacent roof side rail cross bar; Lower-edge beam truss comprises lower-edge beam cross bar and the lower-edge beam pull bar of more than two, is connected with the lower-edge beam pull bar of more than two between adjacent lower edge beam cross bar.Roof side rail cross bar forms node after being connected with roof side rail pull bar between, utilizes the supporting role of roof side rail pull bar, can improve resistance to compression and the bending resistance of roof side rail, thus improves resistance to compression and the bending resistance of upper cover framework.Lower-edge beam cross bar forms node after being connected with lower-edge beam pull bar between, utilizes the supporting role of lower-edge beam pull bar, can improve resistance to compression and the bending resistance of lower-edge beam, thus improves resistance to compression and the bending resistance of lower cover framework.

Further, roof side rail cross bar forms by three, and on same vertical plane, the roof side rail pull bar between adjacent roof side rail cross bar is triangular in shape; Lower-edge beam cross bar forms by three, and on same vertical plane, the lower-edge beam pull bar between adjacent lower edge beam cross bar is triangular in shape.The rectangular triangle of roof side rail pull bar between adjacent roof side rail cross bar, the inclined-plane of right-angled triangle is positioned at the outside of upper cover framework; The rectangular triangle of lower-edge beam pull bar between adjacent lower edge beam cross bar, the inclined-plane of right-angled triangle is positioned at the outside of lower cover framework.Adopt the roof side rail trussed construction of said structure, allow roof side rail truss define space truss structure, further increase the load performance of roof side rail truss.Adopt the lower-edge beam trussed construction of said structure, allow lower-edge beam truss define space truss structure, further increase the load performance of lower-edge beam truss.This structure, naturally form inclined-plane at the edge of upper cover framework and lower cover framework, and when when fluid concrete, inclined-plane has guide effect to concrete flowing, makes concrete cast very smooth and easy.

Further, the upper horizontal truss that draws comprises the upper drag link of more than two and upper vertical support bar, is provided with the upper vertical support bar of more than two on adjacent between drag link, is connected with diagonal web member on adjacent between vertical support bar; Bottom rail draws truss to comprise the lower drag link of more than two and lower vertical support bar, is provided with the lower vertical support bar of more than two between adjacent lower drag link, between adjacent lower vertical support bar, be connected with lower diagonal web member.Above-mentioned horizontal draw truss formed across beam structure, form on-deformable three-legged structure by upper drag link, upper vertical support bar and upper diagonal web member, make the horizontal strength and stiffness drawing truss better, improve horizontal resistance to compression, non-deformability of drawing truss.Above-mentioned bottom rail draw truss formed across beam structure, form on-deformable three-legged structure by lower drag link, lower vertical support bar and lower diagonal web member, make bottom rail draw the strength and stiffness of truss better, improve resistance to compression, non-deformability that bottom rail draws truss.

Further, between cramp bar and drag link, there is node; Be provided with inner support frame inside intermediate support framework, inner support frame comprises internal supporting rod and is located at the interior drag link between adjacent internal supporting rod; Same vertical plane is furnished with described cramp bar and internal supporting rod respectively, and the middle part of internal supporting rod has an interior nodes, on same vertical plane, is connected to connecting rod between the node between all cramp bars and drag link and interior nodes.This structure, can allow intermediate support framework also form trussed construction, improves the ability of intermediate support framework anti-side pressure.

Further, in intermediate support framework, between upper cover framework and lower cover framework, be provided with bearing post, improve bearing value.

Further, be provided with reference column in the inner side of upper cover framework, be provided with lower reference column in the inner side of lower cover framework, the upper end of bearing post is plugged in reference column, and the lower end of bearing post is plugged in lower reference column.When installing bearing post, in utilization, reference column and lower reference column can position bearing post, convenient installation, and when using core, under the effect of the pressure, bearing post is not easy the situation occurring displacement, depart from, and improves bearing performance.

Further, upper reference column is hollow-core construction, and lower reference column is hollow-core construction, and bearing post is hollow-core construction, upper reference column, bearing post and lower reference column up/down perforation.Upper reference column, lower reference column and bearing post are hollow-core construction, when fluid concrete, concrete can through upper reference column, bearing post and lower reference column, by the concrete be poured in upper reference column, bearing post and lower reference column, upper and lower concrete is linked together, improve the integraty of floor.

Further, upper syndeton is upper buckle or upper tied rope; Lower syndeton is lower buckle or lower tied rope, to realize mounting and dismounting fast.

Accompanying drawing explanation

Fig. 1 is the stereogram of open web type truss composite core formwork.

Fig. 2 is the front view of open web type truss composite core formwork.

Fig. 3 is the top view of open web type truss composite core formwork.

Fig. 4 is the schematic diagram of upper cover framework.

Fig. 5 is the schematic diagram of lower cover framework.

Fig. 6 is the schematic diagram of intermediate support framework.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, the utility model is further elaborated.

As shown in Figure 1 to Figure 3, open web type truss composite core formwork comprises the intermediate support framework 200 of more than flexible boot, upper cover framework 100, lower cover framework 300 and one deck.In the present embodiment, intermediate support framework 200 is one.

As Fig. 1,2, shown in 3 and Fig. 4, upper cover framework 100 is trussed construction.Described upper cover framework 100 comprises upper cover outside framework 101 and above horizontally draws truss 102, above horizontally draws truss 102 to be positioned at upper cover outside framework and is connected with upper cover outside framework 101.

Upper cover outside framework 101 is interconnected by multiple roof side rail truss 1 and surrounds.As shown in Figure 4, roof side rail truss 1 comprises roof side rail cross bar 11 and the roof side rail pull bar 12 of more than two, in the present embodiment, be made up of three roof side rail cross bars 11, between adjacent roof side rail cross bar 11, be connected with the roof side rail pull bar 12 of more than two, the junction between roof side rail cross bar 11 and roof side rail pull bar 12 has node; On same vertical plane, the roof side rail pull bar 12 between adjacent roof side rail cross bar 11 is triangle at right angles; The inclined-plane of right-angled triangle is positioned at the outside of upper cover framework 101, allows the outward flange of upper cover framework 100 be inclined-plane.Junction between adjacent roof side rail truss shares a roof side rail pull bar, allows upper cover outside framework 101 in an overall structure, improves strength and stiffness.

As shown in Figure 4, the upper horizontal truss 102 that draws comprises the upper drag link 13 of more than two and upper vertical support bar 14, is provided with the upper vertical support bar 14 of more than two on adjacent between drag link 13, is connected with diagonal web member 15 on adjacent between vertical support bar.Form on-deformable three-legged structure by upper drag link 13, upper vertical support bar 14 and upper diagonal web member 15, make the horizontal strength and stiffness of truss 102 that draw better, improve horizontal resistance to compression, non-deformability of drawing truss.The upper horizontal truss 102 that draws is formed by two, be welded with respectively between the diagonal angle of upper cover outside framework 101 and described upper horizontally draw truss 102, on two, the horizontal truss that draws intersects in centre, can reduce single horizontal span of drawing truss 102 like this, horizontal rigidity of drawing truss 102 in raising.

As Fig. 1,2, shown in 3 and Fig. 5, lower cover framework 300 is trussed construction.Described lower cover framework 300 comprises lower cover outside framework 301 and bottom rail draws truss 302, and bottom rail is drawn truss 302 to be positioned at lower cover outside framework and is connected with lower cover outside framework 301.

Lower cover outside framework 301 is interconnected by multiple lower-edge beam truss 3 and surrounds.As shown in Figure 5, lower-edge beam truss 3 comprises lower-edge beam cross bar 31 and the lower-edge beam pull bar 32 of more than two, in the present embodiment, be made up of three lower-edge beam cross bars 31, between adjacent lower edge beam cross bar 31, be connected with the lower-edge beam pull bar 32 of more than two, the junction between lower-edge beam cross bar 31 and lower-edge beam pull bar 32 has node; On same vertical plane, the lower-edge beam pull bar 32 between adjacent lower edge beam cross bar 31 is triangle at right angles; The inclined-plane of right-angled triangle is positioned at the outside of lower cover framework 301, allows the outward flange of lower cover framework 300 be inclined-plane.Junction between adjacent lower edge beam truss shares a lower-edge beam pull bar, allows lower cover outside framework 301 in an overall structure, improves strength and stiffness.

As shown in Figure 5, bottom rail draws truss 302 to comprise the lower drag link 33 of more than two and lower vertical support bar 34, is provided with the lower vertical support bar 34 of more than two between adjacent lower drag link 33, between adjacent lower vertical support bar, be connected with lower diagonal web member 35.Form on-deformable three-legged structure by lower drag link 33, lower vertical support bar 34 and lower diagonal web member 35, make bottom rail draw the strength and stiffness of truss 302 better, improve resistance to compression, non-deformability that bottom rail draws truss.Bottom rail draws truss 302 to form by two, between the diagonal angle of lower cover outside framework 301, be welded with described bottom rail respectively draw truss 302, two bottom rails draw truss to intersect in centre, can reduce the span that single bottom rail draws truss 302 like this, improve the rigidity that bottom rail draws truss 302.

As Fig. 1,2, shown in 3 and Fig. 6, described intermediate support framework 200 comprises cramp bar 21 and is connected to the drag link 22 between adjacent cramp bar.Between cramp bar 21 and drag link 22, there is node; Be provided with inner support frame inside intermediate support framework 200, inner support frame comprises internal supporting rod 23 and is located at the interior drag link 24 between adjacent internal supporting rod; Same vertical plane is furnished with described cramp bar 21 and internal supporting rod 23 respectively, the middle part of internal supporting rod 23 has an interior nodes 231, on same vertical plane, node between all cramp bars and drag link and be connected to connecting rod 25 between interior nodes 231, intermediate support framework can be allowed also to form trussed construction, improve the ability of intermediate support framework anti-side pressure.

Reference column is provided with in the inner side of upper cover framework 100, upper reference column is hollow-core construction, is provided with lower reference column in the inner side of lower cover framework 300, and lower reference column is hollow-core construction, the upper end of bearing post 4 is plugged in reference column, and the lower end of bearing post 4 is plugged in lower reference column; Upper reference column is hollow-core construction, and lower reference column is hollow-core construction, and bearing post is hollow-core construction, upper reference column, bearing post and lower reference column up/down perforation.When installing bearing post, in utilization, reference column and lower reference column can position bearing post, convenient installation, and when using core, under the effect of the pressure, bearing post is not easy the situation occurring displacement, depart from, and improves bearing performance.In addition, upper reference column, lower reference column and bearing post are hollow-core construction, when fluid concrete, concrete can through upper reference column, bearing post and lower reference column, by the concrete be poured in upper reference column, bearing post and lower reference column, upper and lower concrete is linked together, improve the integraty of floor.

Between upper cover framework 100 and intermediate support framework 200, be provided with syndeton, between lower cover framework 300 and intermediate support framework 200, be provided with lower syndeton.Upper syndeton is upper buckle or upper tied rope; Lower syndeton is lower buckle or lower tied rope, mounts and dismounts core easily and fast.

Flexible boot is enclosed within outside upper cover framework 100, lower cover framework 200 and intermediate support framework 300.

When utilizing mandrel molding cassette ceiling, from the stressed upper analysis of core, the top of core and bottom are mainly born from concrete lateral pressure, the pressure of this concrete lateral pressure and core top and bottom is mainly born in the middle part of core, when pouring concrete is coated to after on core, because of the gravity of concrete self, lateral pressure is much larger than lateral pressure, in the utility model, upper cover framework 100 and lower cover framework 300 are arranged to trussed construction, the resistance to compression improving upper cover framework 100 and lower cover framework 300 can reached, bending resistance, make the mechanical property of core better, and for intermediate support framework 200, because lateral pressure is relatively little, like this, as long as the pressure from upper cover framework 100 and lower cover framework 300 can be born, therefore, as long as intermediate support framework 200 be arranged to by cramp bar and be connected to the requirement that structure that the drag link between adjacent cramp bar forms can reach use, alleviate the weight of whole core, also reach the object of saving material simultaneously, in addition, for upper and lower covers framework, in utilization horizontal draw truss 102 and bottom rail draw truss 302 can allow the top of core and bottom stressed more even, more reliable to the supporting of flexible pouch, be not easy the phenomenon occurring at core place subsiding.Because core of the present utility model is made up of upper cover framework 100, lower cover framework 300 and intermediate support framework 200, when transporting, core is dismantled, and allow multiple upper cover framework 100, multiple lower cover framework 300 overlap, greatly can reduce transport space, reduce cost of transportation, at the scene, in utilization, core fits together by syndeton and lower syndeton, can realize the object of Fast Installation, operation of being more convenient for.

In addition, naturally form inclined-plane at the edge of upper cover framework 100 and lower cover framework 300, when when fluid concrete, inclined-plane has guide effect to concrete flowing, makes concrete cast very smooth and easy.

Because upper cover framework 100, lower cover framework 200 are trussed construction.When fluid concrete, even if flexible pouch has tiny holes, also only have a small amount of concrete to enter in core, the shaping of floor can not be affected.

Claims (10)

1. a kind of open web type truss composite core formwork, comprises the intermediate support framework of more than upper cover framework, lower cover framework and one deck; It is characterized in that: upper cover framework is trussed construction, lower cover framework is trussed construction, and intermediate support framework is located between upper cover framework and lower cover framework; Between upper cover framework and intermediate support framework, be provided with syndeton, between lower cover framework and intermediate support framework, be provided with lower syndeton.

2. open web type truss composite core formwork according to claim 1, is characterized in that: described upper cover framework comprises the upper cover outside framework that surrounded by roof side rail truss and above horizontally draws truss, above horizontally draws truss to be positioned at upper cover outside framework and is connected with upper cover outside framework; Described lower cover framework comprises the lower cover outside framework that surrounded by lower-edge beam truss and bottom rail draws truss, and bottom rail is drawn truss to be positioned at lower cover outside framework and is connected with lower cover outside framework; Described intermediate support framework comprises cramp bar and is connected to the drag link between adjacent cramp bar.

3. open web type truss composite core formwork according to claim 2, is characterized in that: roof side rail truss comprises roof side rail cross bar and the roof side rail pull bar of more than two, is connected with the roof side rail pull bar of more than two between adjacent roof side rail cross bar; Lower-edge beam truss comprises lower-edge beam cross bar and the lower-edge beam pull bar of more than two, is connected with the lower-edge beam pull bar of more than two between adjacent lower edge beam cross bar.

4. open web type truss composite core formwork according to claim 3, is characterized in that: roof side rail cross bar forms by three, and on same vertical plane, the roof side rail pull bar between adjacent roof side rail cross bar is triangular in shape; Lower-edge beam cross bar forms by three, and on same vertical plane, the lower-edge beam pull bar between adjacent lower edge beam cross bar is triangular in shape; The rectangular triangle of roof side rail pull bar between adjacent roof side rail cross bar, the inclined-plane of right-angled triangle is positioned at the outside of upper cover framework; The rectangular triangle of lower-edge beam pull bar between adjacent lower edge beam cross bar, the inclined-plane of right-angled triangle is positioned at the outside of lower cover framework.

5. open web type truss composite core formwork according to claim 2, it is characterized in that: the upper horizontal truss that draws comprises the upper drag link of more than two and upper vertical support bar, be provided with the upper vertical support bar of more than two on adjacent between drag link, be connected with diagonal web member between vertical support bar on adjacent; Bottom rail draws truss to comprise the lower drag link of more than two and lower vertical support bar, is provided with the lower vertical support bar of more than two between adjacent lower drag link, between adjacent lower vertical support bar, be connected with lower diagonal web member.

6. open web type truss composite core formwork according to claim 2, is characterized in that: have node between cramp bar and drag link; Be provided with inner support frame inside intermediate support framework, inner support frame comprises internal supporting rod and is located at the interior drag link between adjacent internal supporting rod; Same vertical plane is furnished with described cramp bar and internal supporting rod respectively, and the middle part of internal supporting rod has an interior nodes, on same vertical plane, is connected to connecting rod between the node between all cramp bars and drag link and interior nodes.

7. open web type truss composite core formwork according to claim 2, is characterized in that: in intermediate support framework, be provided with bearing post between upper cover framework and lower cover framework.

8. open web type truss composite core formwork according to claim 7, it is characterized in that: be provided with reference column in the inner side of upper cover framework, be provided with lower reference column in the inner side of lower cover framework, the upper end of bearing post is plugged in reference column, and the lower end of bearing post is plugged in lower reference column.

9. open web type truss composite core formwork according to claim 8, is characterized in that: upper reference column is hollow-core construction, and lower reference column is hollow-core construction, and bearing post is hollow-core construction, upper reference column, bearing post and lower reference column up/down perforation.

10. open web type truss composite core formwork according to claim 1, is characterized in that: upper syndeton is upper buckle or upper tied rope; Lower syndeton is lower buckle or lower tied rope.