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Title:
THREADED ROD CONNECTOR WITH ROTATIONALLY LOCKED COLLAR
Document Type and Number:
WIPO Patent Application WO/2021/032536
Kind Code:
A1
Abstract:
Threaded rod connector comprising a housing having a cavity for receiving a threaded rod therein, wherein the cavity has a mouth, and an insert comprising a plurality of rod engagement segments, which are arranged within the cavity, wherein the cavity has a tapered zone tapering towards the mouth for wedging the rod engagement segments against the threaded rod, wherein the insert further comprises a plurality of segment carrying arms, wherein each of the segment carrying arms carries at least one of the rod engagement segments, wherein the segment carrying arms form a cage for accommodating the threaded rod. The insert further comprises a collar, which is connected to the segment carrying arms, and which interconnects the segment carrying arms, and the cavity has a collar locking zone, in which the collar is arranged, wherein the housing rotationally locks the collar arranged in the collar locking zone to the housing.

Inventors:
ZILTENER MICHAEL (CH)
Application Number:
PCT/EP2020/072495
Publication Date:
February 25, 2021
Filing Date:
August 11, 2020
Export Citation:
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Assignee:
HILTI AG (LI)
International Classes:
F16B37/08; E04B1/41
Foreign References:
US4618300A1986-10-21
KR100470216B12005-02-05
GB628316A1949-08-26
US20150275505A12015-10-01
US20020001504A12002-01-03
US8434725B22013-05-07
US5468105A1995-11-21
US20180187705A12018-07-05
EP2017485A22009-01-21
GB624714A1949-06-15
Attorney, Agent or Firm:
HILTI AKTIENGESELLSCHAFT (LI)
Download PDF:
Claims:
CLAIMS

1. Threaded rod connector comprising,

- a housing (1) having a cavity (10) for receiving a threaded rod therein, wherein the cavity (10) has a mouth (11) for inserting the threaded rod into the cavity (10), and

- an insert (3) comprising a plurality of rod engagement segments (50), which are ar ranged within the cavity (10), wherein each of the rod engagement segments (50) has a mating thread structure (51) for engaging the thread of the threaded rod,

- wherein the cavity (10) has a tapered zone (14) tapering towards the mouth (11) of the cavity (10) for wedging the rod engagement segments (50) against the threaded rod,

- wherein the insert (3) further comprises a plurality of segment carrying arms (40), wherein each of the segment carrying arms (40) carries at least one of the rod en gagement segments (50),

- wherein the segment carrying arms (40) form a cage (44) for accommodating the threaded rod, c h a r a c t e r i z e d in

- that the insert (3) further comprises a collar (30), which is connected to the segment carrying arms (40), and which interconnects the segment carrying arms (40),

- that the cavity (10) has a collar locking zone (16), in which the collar (30) is, at least partly, arranged,

- wherein the housing (1) rotationally locks the collar (30) arranged in the collar lock ing zone (16) to the housing (1), thereby preventing spinning of the insert (3) within the cavity (10).

2. Connector according to claim 1 , c h a r a c t e r i z e d in that

- an engagement surface (39) is provided on the collar (30), and that

- within the collar locking zone (16), the cavity (10) mates with the engagement sur face (39) to rotationally lock the collar (30) arranged in the collar locking zone (16) to the housing (1), thereby preventing spinning of the insert (3) within the cavity (10).

3. Connector according to any of the preceding claims, c h a r a c t e r i z e d in that the segment carrying arms (40) project from the collar (30) towards the mouth (11) of the cavity (10).

4. Connector according to any of the preceding claims, characterized in that the collar (30) has a rod accommodation hole (34) for accommodating the threaded rod.

5. Connector according to claim 4, characterized in that the rod accommodation hole (34) is a through hole.

6. Connector according to any of the preceding claims, characterized in that that the collar (30) radially projects over the cage (44).

7. Connector according to any of the preceding claims, characterized in that the insert (3) is rotationally locked to the housing (1) at the collar (30) only.

8. Connector according to any of the preceding claims, characterized in that the collar (30) has axial play within the collar locking zone (16).

9. Connector according to any of the preceding claims, characterized in that the insert (3) has spring-tensionless axial play within the cavity (10).

10. Connector according to any of the preceding claims, characterized in that the insert (3) is monolithic.

11. Connector according to any of the preceding claims, characterized in that the collar (30) is C-shaped or a closed ring.

Description:
Threaded rod connector with rotationally locked collar

The invention relates to a threaded rod connector according to the preamble of claim 1. Such a connector comprises a housing having a cavity for receiving a threaded rod therein, where in the cavity has a mouth for inserting the threaded rod into the cavity, and an insert compris ing a plurality of rod engagement segments, which are arranged within the cavity, wherein each of the rod engagement segments has a mating thread structure for engaging the thread of the threaded rod, wherein the cavity has a tapered zone tapering towards the mouth of the cavity for wedging the rod engagement segments against the threaded rod, wherein the in sert further comprises a plurality of segment carrying arms, wherein each of the segment carrying arms carries at least one of the rod engagement segments, wherein the segment carrying arms form a cage for accommodating the threaded rod.

US8434725 A, US5468105 A and US2018187705 A1 disclose quick acting threaded rod connectors having threaded rod engagement segments arranged in a tapered cavity, where in the taper of the cavity wedges the threaded rod engagement segments against the threaded rod. In each case, the threaded rod engagement segments are axially biased, by an axial compression spring, against the taper of the cavity, to ensure initial engagement of the threaded rod.

EP2017485 A2 describes a channel nut having threaded shells through which a threaded rod can be pushed. The channel nut has an operating cylinder, which is rotationally connected to the threaded shells to manually rotate the shells in order to adjust the height of the threaded rod held within the channel nut. After height adjustment, the operating cylinder can be manu ally pushed into the channel nut, which locks the shells against the threaded rod.

GB624714 A describes a quick connector for threaded rods, which comprises a plurality of rod engagement segments arranged within a cavity in a housing. The rod engagement seg ments are intended to be wedged against the threaded rod for locking the threaded rod. For initial engagement, the rod engagement segments are radially biased against the threaded rod by elastic arms, which extend from the rod engagement segments towards the bottom of the cavity, and which are interconnected with each other near the bottom of the cavity.

It is an object of the invention to provide a threaded rod connector which provides particularly good functionality and versatility, whilst being particularly reliable and easy to manufacture.

This object is achieved by a device according to claim 1. Dependent claims refer to preferred embodiments of the invention.

The invention provides that the insert further comprises a collar, which is connected to the segment carrying arms, and which interconnects the segment carrying arms, that the cavity has a collar locking zone, in which the collar is, at least partly, arranged, wherein the housing rotationally locks the collar arranged in the collar locking zone to the housing, thereby pre venting spinning of the insert within the cavity.

Thus, an anti-spinning mechanism is provided, which prevents the rod engagement seg ments from spinning within the housing when a threaded rod is, e.g. for height adjustment, tensioning of the threaded rod or detachment of the threaded rod, screwingly moved within the rod engagement segments whilst they engage the threaded rod. Such an anti-spinning mechanism can provide particularly versatile and reliably operation. In particular, the anti spinning mechanism is provided via the collar, which is on the one hand connected to the rod engagement segments via the segment carrying arms, and which is on the other hand locked against rotation by the housing. Accordingly, the anti-spinning mechanism can be provided remote from the rod engagement segments and/or the segment carrying arms, which allows particularly easy manufacture of the connector, e.g. since the cavity can be provided with generally circular symmetric shape.

The housing may rotationally lock the collar arranged in the collar locking zone with some angular play, since this might be easier to manufacture and still prevents spinning of the in sert within the cavity. However, it is particularly preferred that the housing rotationally locks the collar arranged in the collar locking zone tightly, i.e. without allowing any rotational mo tion between the collar and the housing, as this can provide particularly reliable operation.

The housing could for example be a threaded socket, a screw head or a cast-in anchor in tended to be cast into concrete. The cavity can be a blind hole, wherein the bottom of the hole could be formed by an element integral with the rest of the housing or by a separate plug. Or it can be a through hole. In this case, a ring-shaped bottom can be provided. The threaded rod can be inserted into the cavity via the mouth of the cavity. In particular, the mouth can be open, or it can be covered by structures that can easily be penetrated by the threaded rod.

The rod engagement segments are arranged within the cavity so as to surround the threaded rod inserted into the cavity. The mating thread structure for engaging the thread of the threaded rod is an internal thread structure, whereas the thread of the threaded rod is an external thread. The mating thread structure can be a thread segment or a more rudimentary structure, consisting only of fractions of a thread. The mating thread structure corresponds to the thread of the threaded rod and/or is able to mesh with and engage into the thread of the threaded rod.

The tapered zone tapers towards the mouth, i.e. it becomes narrower as it approaches the mouth. In particular the tapered zone of the cavity has a wide end and a narrow end, which is closer to the mouth of the cavity than the wide end. The tapered zone is able to radially wedge the rod engagement segments against the threaded rod when the threaded rod is pulled axially through the mouth out of the cavity.

In particular, the insert has elasticity to allow the threaded rod to ratchet into the mating thread structures of the rod engagement segments. Accordingly, the insert is sufficiently elastic to allow, without breaking, the rod engagement segments to displace radially outward ly when the mating thread structures of the rod engagement segments temporarily become misaligned with the corresponding thread of the threaded rod as the threaded rod is dis placed axially with respect to the rod engagement segments. In particular, the elasticity of the insert can radially bias the mating thread structures against the thread of the threaded rod for provisional engagement.

Each of the segment carrying arms carries at least one of the rod engagement segments, in particular at a segment connection end of the respective arm. More preferably, each of the segment carrying arms carries precisely one of the rod engagement segments, i.e. the num ber of rod engagement segments equals the number of segment carrying arms. The thread ed rod connector comprises at least two rod engagement segments and at least two seg ment carrying arms. Preferably, the threaded rod connector comprises four rod engagement segments and four segment carrying arms. The rod engagement segments are, in particular, arranged in an annular relationship, preferably with equidistant spacing. The threaded rod connector could also comprise auxiliary rod engagement segments, which are not connected to a segment carrying arm, and/or the insert could also comprise auxiliary arms, which are not directly connected to a rod engagement segment.

In particular, the segment carrying arms can be interconnected by the collar at interconnec tion ends of the segment carrying arms. The interconnection end of each of the segment carrying arms is located opposite to the segment connection end on the respective segment carrying arm, and/or the longitudinal direction of the respective segment carrying arm ex tends between its segment connection end and its interconnection end.

At least some of the rod engagement segments, preferably all of them, can have, in a rear ward zone facing the segment carrying arms, an outside chamfer intended for contacting the housing in the tapered zone of the cavity. Providing the rod engagement segments with an outside chamfer that corresponds at least approximately to the taper of the tapered zone of the cavity can increase the contact surface between the rod engagement segments and the housing, thereby efficiently counteracting jamming.

The collar could be C-shaped, but preferably, it is a closed ring, which can provide particular ly good robustness whilst being easy to manufacture.

The cage comprises the segment carrying arms, which are preferably arranged parallel to each other. In particular, the cage can cage the threaded rod.

It is particularly preferred that an engagement surface is provided on the collar, and that with in the collar locking zone, the cavity mates with the engagement surface to rotationally lock the collar arranged in the collar locking zone to the housing, thereby preventing spinning of the insert within the cavity. Accordingly, the collar has an engagement surface, in particular with non-circular outline, and the housing rotationally locks the collar that is arranged in the collar locking zone to the housing by means of a positive mechanical engagement, thereby preventing spinning of the insert within the cavity. In other words, rotational locking of the collar within the housing is effected by corresponding geometric structures that are mechani cally interlocked. An anti-spinning mechanism based on positive mechanical engagement can provide axial mobility of the insert in a particularly easy manner, thereby providing a par ticularly easy-to-manufacture and reliable wedging mechanism for locking the rod engage ment segments against the threaded rod. The engagement surface can e.g. include key- ways, keyseats, splines or others. It is particularly preferred that the engagement surface comprises polygonal flats. Advantageously, the segment carrying arms project from the collar towards the mouth of the cavity. In other words, the segment carrying arms extend between the collar and the mouth of the cavity. Thus, the collar is located remote from the mouth of the cavity, which allows particularly easy and efficient axial locking of the insert by means of an axial stop acting against the collar. In particular, the collar can be located at a tip end of the insert that is re mote from the rod engagement segments, leading to a particularly compact design, further facilitating manufacture.

It is preferred that the rod engagement segments do not stick out of the cavity. Accordingly, the rod engagement segments can be located axially between the collar and the mouth of the cavity.

It is particularly preferred that the collar has a rod accommodation hole for accommodating the threaded rod. This can allow to insert the threaded rod particularly deep into the cavity, in particular when the segment carrying arms project from the collar towards the mouth of the cavity. In particular, the rod accommodation hole can be a through hole, for particularly deep threaded rod insertion.

According to another preferred embodiment of the invention, the collar radially projects over the cage, radially in particular with respect to the longitudinal axis of the insert. Amongst oth ers, this can provide particularly efficient axial locking of the insert at the collar and can an allow providing a particularly deep rod accommodation hole for accommodating the threaded rod in a particularly easy way, thereby further improving operation.

Preferentially, the insert is rotationally locked to the housing at the collar only, in particular only at its engagement surface. Accordingly, the plurality of segment carrying arms and the rod engagement segments would be free to rotate in the cavity if they were not connected to the collar. This allows to provide the cavity with a generally circular symmetric zone, wherein the segment carrying arms and the rod engagement segments are, at least partly, arranged in the circular symmetric zone. This can further facilitate manufacturing.

The collar preferentially has axial play within the collar locking zone. The collar can thus travel a certain distance without leaving the collar locking zone, preferably without the collar locking zone disengaging from the engagement surface of the collar. This can allow, whilst being easy to manufacture, particularly reliable wedging action. Advantageously, the insert has spring-tensionless axial play within the cavity. Accordingly, the insert can axially travel a certain distance within the cavity without changing tension of a spring. Initial engagement of the threaded rod can be effected by elasticity of the insert, and therefore, a compression spring axially biasing the rod engagement segments against the tapered zone is regularly not required, thereby further facilitating manufacture.

The insert is preferably monolithic, further improving robustness and facilitating manufacture.

The following description explains the invention using illustrative embodiments and drawings.

Figure 1 is an isometric view of an insert intended to be used in a threaded rod connector. Figure 2 is a top view of the insert of figure 1.

Figure 3 is a sectional side view of a first threaded rod connector including the insert of fig ures 1 and 2, in a first configuration.

Figure 4 is a sectional side view of the threaded rod connector of figure 3, in a second con figuration.

Figure 5 is an exploded view of the threaded rod connector of figure 3.

Figure 6 is an isometric view of the threaded rod connector of figure 3.

Figure 7 is a sectional side view of a second threaded rod connector including the insert of figures 1 and 2, in a first configuration.

Figure 8 is a sectional side view of the threaded rod connector of figure 7, in a second con figuration.

Figure 9 is an exploded view of the threaded rod connector of figure 7.

Figures 1 and 2 illustrate an insert 3 intended to be used as a part of a threaded rod con nector. The insert 3 comprises a plurality, four in the present case, of rod engagement seg ments 50. The rod engagement segments 50 have a shell-like shape each and surround a receiving space for a threaded rod. Each of the rod engagement segments 50 has, on its inside facing the receiving space, a mating thread structure 51 mating with the external thread of the threaded rod. The rod engagement segments 50 are arranged axially abreast. The mating thread structures 51 are of the inner thread type. In the shown embodiment, each of the mating thread structures 51 is a continuous cut-out of an internal thread, but the mat ing thread structures 51 could also be differently shaped. In particular, they could be more rudimentary and could for example include discontinuous thread structures.

The insert 3 further comprises a plurality of, four in the present case, segment carrying arms 40. In particular, the number of segment carrying arms 40 equals the number of rod en- gagement segments 50. Each of the segment carrying arms 40 has a segment connection end 45 and an interconnection end 43, wherein the segment connection end 45 and the in terconnection end 43 are opposite ends of the respective segment carrying arm 40. Each of the segment carrying arms 40 has one of the rod engagement segments 50 connected there to, namely at the segment connection end 45 of the respective segment carrying arm 40. In the present embodiment, connection between the segment carrying arms 40 and the associ ated rod engagement segments 50 is direct in each case. The segment carrying arms 40 form a cage 44, which can accommodate the threaded rod. In the present embodiment, the segment carrying arms 40 are parallel to each other and parallel to the axial direction, i.e. parallel to the longitudinal axis of the insert 3.

The insert 3 further comprises a collar 30, which is directly connected to the segment carry ing arms 40 at their respective interconnection ends 43. The collar 30 thus directly intercon nects the segment carrying arms 40, and it also interconnects the rod engagement segments 50, namely indirectly, via the segment carrying arms 40. The collar 30 could e.g. be C- shaped, or it can, as shown here, be a closed annulus. The collar 30 surrounds a rod ac commodation hole 34 for accommodating the threaded rod. The rod accommodation hole 34 is, by way of example, a through hole. The rod accommodation hole 34 is axially aligned with the cage 44 of segment carrying arms 40 and with the receiving space that is located be tween the rod engagement segments 50. Consequently, the straight threaded rod can be located, simultaneously, within the receiving space of the rod engagement segments 50, within the cage 44 and within the rod accommodation hole 34.

The insert 3 is elastic so that a threaded rod with an external thread mating with the mating thread structure 51 can be ratcheted into the rod engagement segments 50. In this ratcheting process, the rod engagement segments 50 are displaced radially outwardly when the mating thread structures 51 and the external thread of the threaded rod are temporarily out of axial alignment, and the elasticity of the insert 3, in particular of the segment carrying arms 40, can radially return the rod engagement segments 50 into engagement with the external thread of the threaded rod when axial alignment between the mating thread structures 51 and the ex ternal thread of the threaded rod is restored. In particular, the elasticity of the insert 3 can radially bias the rod engagement segments 50 at their mating thread structures 51 against the threaded rod. Elasticity might be primarily caused by the segment carrying arms 40, whereas the collar 30 might be relatively rigid.

The collar 30 radially projects over the cage 44 of segment carrying arms 40. It has a planar, annular stop surface 38 which projects radially on the insert 3. The stop surface 38 faces the segment carrying arms 40. In the shown embodiment, the stop surface 38 defines a forward boundary of the collar 30. However, this is an example only, and the collar 30 could e.g. also have a forward zone located between the segment carrying arms 40 and the stop surface 38.

The collar 30 of the insert 3 furthermore comprises an engagement surface 39, which is pro vided for positive mechanical engagement of the collar 30 for rotationally coupling the insert 3 to another element, in particular for rotationally locking the insert 3 in a housing 1 or for grasping the insert 3 with a wrench tool for rotating the insert 3. In the shown embodiment, the engagement surface 39 is a polygonal surface comprising a plurality of flats arranged to give a polygonal outline. However, other embodiments of engagement surfaces are also possible, for example comprising keys, keyseats, splines, channels or protrusions.

At their free ends, which are located remote from the segment carrying arms 40 and facing away from the collar 30, the rod engagement segments 50 have a chamfered tip 52, which can facilitate insertion into a cavity 10 during assembly of a threaded rod connector, or which can increase contact surface with a tapered zone 14 of a cavity 10. The rearward ends of the rod engagement segments 50, i.e. the ends facing the collar 30 and the segment carrying arms 40, also have an outside chamfer, e.g. in order to increase contact surface with a ta pered zone 14 of a cavity 10.

The insert 3 further comprises a ring shoulder 49, which is a broken-type ring shoulder 49 located on the interconnection ends 43 of the segment carrying arms 40 in the shown em bodiment, but which could also be located on the above-mentioned forward zone of the collar 30. This ring shoulder 49 is for laterally supporting the insert 3 within a cavity 10.

The insert 3 is monolithic and preferably consists of metal, more preferably steel. The insert 3 has rotational symmetry, four-fold rotational symmetry in the present case, i.e. rotation by 90° maps the insert 3 onto itself.

Figures 3 to 6 show a first embodiment of a threaded rod connector that comprises the insert 3 of figures 1 and 2.

In addition to the insert 3 of figures 1 and 2, the threaded rod connector comprises a housing 1, which has an elongate cavity 10 provided therein. The cavity 10 extends parallel to the longitudinal axis of the connector. At its first end, the cavity 10 has a mouth 11 , which allows to insert a threaded rod into the cavity 10. At its opposite second end, the cavity has a closed bottom 18. The cavity 10 is thus a blind hole. Closure of the cavity 10 at its bottom 18 is ef fected by a plug 85 that is plugged into the housing 1.

The insert 3 is arranged within the cavity 10, in the present embodiment in its entirety. The insert 3 and the cavity 10 are arranged coaxially. In the present embodiment, the insert is located collar-first in the cavity 10, i.e. the collar 30 is located closer to the bottom 18 of the cavity 10 than the rod engagement segments 50, and the segment carrying arms 40 project from rod engagement segments 50 in a direction away from the mouth 11, towards the bot tom 18. In other words, the segment carrying arms 40 project from the collar 30 towards the mouth 11 , away from the bottom 18.

The cavity 10 comprises a collar locking zone 16, which is located close to the bottom 18 of the cavity 10, in particular adjacent to the bottom 18. The collar 30 and in particular its en gagement surface 39 are located within the collar locking zone 16. In the collar locking zone 16, the cavity 10 has a cross-section that mates with the engagement surface 39 of the collar 30. As a consequence, the housing 1 engages and rotationally locks the collar 30 and thus the insert 3 by means of positive mechanical engagement. Rotational lock can be with some angular play, or, as in case of the present embodiment, angularly tight.

Outside of the collar locking zone 16, the cavity 10 generally has circular symmetry. Thus, the segment carrying arms 40 and the rod engagement segments 50 would be free to rotate in the cavity 10 if they were not connected to the collar 30. In other words, the insert 3 is rota tionally locked to the housing 1 at the collar 30 only, namely at its engagement surface 39.

The cavity 10 moreover comprises a tapered zone 14, in which the cavity 10 narrows as it approaches the mouth 11. This tapered zone 14 is located in the cavity 10 axially between the collar locking zone 16 and the mouth 11. In the tapered zone 14, the wall of the cavity 10 provided by the housing 1 forms a wedge surface, which wedge surface radially displaces rod engagement segments 50 sliding thereon radially inwardly when the rod engagement segments 50 are moved axially towards the mouth 11. The tapered zone 14 faces the rod engagement segments 50 and the bottom 18 of the cavity 10.

The insert 3 has some axial play within the cavity 10. As a consequence, the insert 3 can be moved between the position shown in figure 3, in which the wall of the cavity 10 does not radially act on the rod engagement segments 50, and in which the insert 3 abuts on the bot tom 18 of the cavity 10, and the position shown in figure 4, in which the insert 3 is located axially closer to the mouth 11 of the cavity. In the position shown in figure 4, the wall of the cavity 10 in the tapered zone 14 radially acts against the rod engagement segments 50, in particular to lock the rod engagement segments 50 to a threaded rod. The engagement sur face 39 has sufficient axial length so that the positive mechanical engagement and thus the rotational lock between the housing 1 and the insert 3 is maintained both in the positions shown in figure 3 and in figure 4.

When a threaded rod is installed within the threaded rod connector, the threaded rod is in serted via the mouth 11 into the cavity 10, where it first abuts against the rod engagement segments 50. If not already in the maximum insertion depth position shown in figure 3, this abutment will push the insert 3 deeper into the cavity 10, until the insert 3 abuts on the bot tom 18, as shown in figure 3. When the threaded rod is then pushed even deeper into the cavity 10, it ratchets into the rod engagement segments 50, where it is provisionally engaged by the mating thread structures 51 by means of the elasticity of the insert 3. If the threaded rod is subsequently loaded in a direction pointing out of the mouth 11, the threaded rod will drag along the rod engagement segments 50, until they are wedged against the threaded rod by the tapered zone 14 of the cavity 10, resulting in tight engagement of the threaded rod, for example in a configuration shown in figure 4.

Due to the elasticity of the insert 3, the threaded rod connector can engage the threaded rod without the need to axially bias the rod engagement segments 50 against the tapered zone 14. Thus, the insert 3 can have spring-tensionless play within the cavity 10.

Since the insert 3 is rotationally locked within the housing 1 via the collar locking zone 16, it is possible to unscrew the threaded rod from the insert 3 without the insert 3 spinning within the housing 1.

The housing 1 can form the stem of a cast-in anchor that is intended to be cast into concrete. Such a cast-in anchor can comprise an anchor flange 81, attached to the housing 1 at its end remote from the mouth 11 , for anchoring the cast-in anchor within the concrete. Preferably, a base holder 82 might be provided for mounting the cast-in anchor to a shuttering before cast ing the concrete, wherein the shuttering might be a wood form, a pan deck or a metal deck.

Figures 7 to 9 show a second embodiment of a threaded rod connector that comprises the insert 3 of figures 1 and 2.

In addition to the insert 3 of figures 1 and 2, the threaded rod connector again comprises a housing 1 which has an elongate cavity 10 provided therein. The cavity 10 extends parallel to the longitudinal axis of the connector. At its first end, the cavity 10 has a mouth 11, which allows to insert a threaded rod into the cavity 10. At its opposite second end, the cavity has an incomplete, ring-shaped bottom 18. The cavity 10 is thus a stepped hole.

The insert 3 is arranged within the cavity 10, but only partly in the present embodiment, i.e. a part of the insert 3, in particular its collar 30, sticks out of the cavity 10. The insert 3 and the cavity 10 are arranged coaxially. In the present embodiment, the insert is located with the rod engagement segments 50 first in the cavity 10, i.e. the rod engagement segments 50 are located closer to the bottom 18 of the cavity 10 than the collar 30, and the segment carrying arms 40 project from rod engagement segments 50 rearwards, in a direction towards the mouth 11, away from the bottom 18. In particular, each of the segment carrying arms 40 ex tends, originating from its segment connection end 45, towards the mouth 11 of the cavity 10. In other words, the segment carrying arms 40 project from the collar 30 towards the bottom 18.

The cavity 10 once again comprises a tapered zone 14, in which the cavity 10 narrows as it approaches the mouth 11. In the tapered zone 14, the wall of the cavity 10 provided by the housing 1 forms a wedge surface, which wedge surface radially displaces rod engagement segments 50 sliding thereon radially inwardly when the rod engagement segments 50 are moved axially towards the mouth 11. The tapered zone 14 faces the rod engagement seg ments 50 and the bottom 18 of the cavity 10.

The insert 3 has some axial play within the cavity 10. Consequently, the insert 3 can be moved between the maximum insertion depth position shown in figure 7, in which the collar 30 abuts on the housing 1 , to the position shown in figure 8, in which the insert 3 is located further out of the cavity 10. In the position of figure 7, the wall of the cavity 10 does not radial ly act on the rod engagement segments 50, whereas in the position of figure 8, the wall of the cavity 10 in the tapered zone 14 radially acts against the rod engagement segments 50, in particular to lock the rod engagement segments 50 to a threaded rod.

The housing 1 has a flat, annular bearing surface 8 surrounding the cavity 10. The stop sur face 38 of the collar 30 faces this bearing surface 8 and abuts against the bearing surface 8 when the maximum insertion depth position of figure 7 is reached, thus preventing the collar 30, in particular its engagement surface 39, from being drawn completely into the cavity 10. Abutment of the stop surface 38 against the bearing surface 8 also prevents the rod en gagement segments 50 from abutting against the bottom 18 of the cavity 10, thus ensuring free movement of the rod engagement segments 50 when the threaded rod is ratcheted in. The insert 3 is free to rotate in the cavity 10. In particular, the cavity 10 has generally circular symmetry. Since the bearing surface 8 is flat, the insert 3 can rotated without axial displace ment even when the stop surface 38 abuts against the bearing surface 8.

When a threaded rod is installed within the threaded rod connector, the threaded rod is in serted via the mouth 11 into the cavity, where it abuts against the rod engagement segments 50 from inside the cage 44 of segment carrying arms 40. If not already in the maximum inser tion depth position of figure 7, this abutment will first push the insert 3 deeper into the cavity

10, until the maximum insertion depth position of figure 7, where the insert 3 abuts on its stop surface 38 against the bearing surface 8, is reached. When the threaded rod is then pushed even deeper into the cavity 10, it ratchets into the rod engagement segments 50, where it is provisionally engaged by the mating thread structures 51 by means of the elasticity of the insert 3. If the threaded rod is subsequently loaded in a direction pointing out of the mouth

11, the threaded rod will drag along the rod engagement segments 50, until they are wedged against the threaded rod by the tapered zone 14 of the cavity 10, resulting in tight engage ment of the threaded rod, for example in a configuration shown in figure 8.

Due to the elasticity of the insert 3, the threaded rod connector can engage the threaded rod without the need to axially bias the rod engagement segments 50 against the tapered zone 14. Thus, the insert 3 can have spring-tensionless play within the cavity 10.

Since the insert 3 is free to rotate within the housing 1, the threaded rod engaged by the rod engagement segments 50 can be axially displaced (for example for tensioning the threaded rod, detaching the threaded rod or adjusting the height of the threaded rod) without the need to rotate the threaded rod itself. Rotation of the insert 3 can for example be effected by man ually grasping the collar 30, or by engaging the engagement surface 39 by a mating wrench tool.

The ring shoulder 49 of the insert 3, which is located adjacent to the stop surface 38, can laterally abut against the wall of the cavity 10 when the insert 3 is laterally loaded, which can improve shear characteristics of the threaded rod connector.

The housing 1 can be attached to the head 88 of a screw anchor 89, in particular with the cavity 10 orientated coaxially with the screw anchor 89. For example, the housing 1 can be screwingly connected to the head 88, as shown here. Alternatively, the housing 1 and the head 88 could also be monolithic.