DEVICE FOR CONNECTING BARS END-TO-END

Abstract

A device for connecting bars end-to-end includes a hollow body having an internal cavity with at least one bar insertion opening and a longitudinal axis extending through the at least one insertion opening, and a plurality of radially adjustable clamping elements. The device further includes at least one locking element movably arranged inside the hollow body. The internal cavity of the hollow body has at least one slope inclined relative to the longitudinal axis of the hollow body. The at least one locking element has an inclined face that matches the profile of the at least one slope and a gripping face with at least one protrusion.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows a perspective view of a device for connecting bar ends according to a first embodiment of the present invention.

FIG. 2 shows a cross-sectional view of the embodiment shown in FIG. 1.

FIG. 3 shows a cross-sectional view of a variant of the first embodiment where a corrosion-protection or binding substance has been injected inside the body.

FIG. 4 shows a perspective view of a device for connecting bar ends according to a second embodiment of the present invention.

FIG. 5 shows a perspective view of a device for connecting bar ends according to a third embodiment of the present invention.

FIG. 6 shows a cross-sectional view of the device for connecting bar ends according to a further embodiment of the present invention.

FIG. 7 a to 7f show perspective views of various locking elements.

FIG. 8 shows a cross-sectional view of a device for connecting bars end-to-end according to a fourth embodiment of the present invention adapted to connect bars of different diameters.

FIG. 9 shows a cross-sectional view of a device for connecting bars end-to-end according to a fifth embodiment of the present invention provided with a pushing means.

FIG. 10 shows a cross-sectional view of a device for connecting bars end-to-end according to a sixth embodiment of the present invention, also provided with a pushing means.

FIG. 11 shows a cross-sectional view of a device for connecting bars end-to-end according to a seventh embodiment of the present invention adapted to receive mainly compressive forces.

FIG. 12 shows a cross-sectional view of a device for connecting bars end-to-end according to a seventh embodiment of the present invention adapted to receive both tensile and compressive forces.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the invention are discussed in the following with reference to the enclosed drawings.

A device 1 for connecting the ends 2′ of a bar according to a first embodiment of the present invention is schematically shown in a perspective view in FIG. 1 as well as in a cross-sectional view in FIG. 2. The device is adapted for connecting rebars and the like end-to-end as they are used in construction, for instance, in reinforced concrete structures. The device 1 comprises a hollow body 10 having an internal cavity 12 which, in the present embodiment, comprises two insertion openings 14 through which a longitudinal axis extends. The direction of extension of the longitudinal axis coincides with the direction of extension of the bars 2 to be connected (FIG. 2).

Furthermore, the device 1 comprises a plurality of clamping screws 16 which are fitted into threaded holes formed in the hollow body 10. The screws may have a reduced neck so as to produce a defined failure. As can be seen in FIG. 2, the screws 16 are adapted to press on the bars 2 inserted into the hollow body 10.

Further, the device 1 comprises two locking elements 18 which are movably arranged inside the internal cavity 12 of the hollow body 10. Specifically, the internal cavity 12 of the body 10 comprises two slopes 12′ which are inclined relative to the longitudinal axis of the body 10, and the locking elements 18 each comprise a inclined face 18′ which matches the profile of the corresponding slope 12′ and is in contact therewith. In addition, each locking element 18 has a gripping face 18″ having a plurality of rack teeth. The gripping face 18″ is adapted to grip and fix the respective bar 2 together with the screws 16. Therefore, it is preferred that the gripping faces 18″ are generally parallel to the longitudinal axis of the bars 2 and body 10.

As can be seen in FIG. 2, the device 1 further comprises stop means 20, for example in the form of stop or separation walls. As shown in FIG. 6, this stop or separation wall 20 may also fully separate the internal cavity 12 in two parts.

For applications where the connection needs to grip or bond with an external surrounding material, for example in concrete construction, ribs or grooves 24 may be provided on the external surface of the body 10.

The connection is achieved by inserting the ends 2′ of bars 2 until they hit the wall 20. The screws 16 are then tightened either until a given torque, or until their heads shear off, thereby forcing the ends 2′ of bars 2 against the gripping face 18″ of the locking elements 18, and locking themselves into the surface material of the bars 2.

The bars 2 are then put in use and sustain a tensile load. This tensile load tends to pull both bars apart, along with the locking elements 18 thanks to the gripping achieved on their gripping faces 18″. When the locking elements 18 move apart by sliding over the slopes 12′, they force their grip 18″ further into the material of the bars 2. Thus, the resistance of the device increases with the load applied on the bars.

FIG. 3 relates to a second embodiment for applications where it is necessary to fill up the cavity 12 with a corrosion-protection or binding substance, end caps 26 may be provided to close the spaces at each extremity of the connection, and a hole 28 may be provided in the body 10, through which the substance may be poured or injected.

FIGS. 4 and 5 show that the external shape of the hollow body 10 may be widely varied within the present invention. Further, the device 1 may comprise one row or also plural rows of screws 16, as shown in FIG. 5.

Also the shape of the locking elements 18 is not specifically limited in the present invention. Various examples of suitable locking elements 18 are shown in FIGS. 7A to 7G. For instance, the inclined face 18′ may be flat or curved just like the gripping face 18″. Of course, further designs are possible.

FIG. 8 shows an embodiment which is adapted to connecting bars 2 having different diameters. For this purpose, the locking elements 18 have a different radial thickness. Specifically, in FIG. 8, the locking element 18 on the left hand side is adapted to grip a bar 2 having a smaller diameter and, therefore, itself has a smaller radial thickness than the locking element 18 on the right hand side.

FIGS. 9 and 10 show a sixth and seventh embodiment, respectively, with additional pushing means 22 for pushing the locking elements 18 against the ends 2′ of bars 2 prior to the tightening of screws 16. This feature is illustrated in FIG. 9 with a cam 23 that is rotated around its axis. In FIG. 10 the pushing means 22 comprises a central screw 25 that pushes on the rear faces of the locking elements 18.

FIG. 11 schematically shows an eighth embodiment of the present invention for cases where the connection must withstand not tensile, but mainly compression efforts. In this embodiment, the slopes 12′ are diverging towards the insertion openings 14.

Under a compression effort, the locking elements 18 are moving towards the center of the body, thereby securing the clamping of the bars 2.

FIG. 12 schematically shows an ninth embodiment of the present invention for the cases where the connection must withstand alternate cyclic tensile and compression efforts. In this embodiment, a total of four locking elements 18a, 18b are provided, namely two locking elements 18a, 18b per bar 2. Further, the locking elements 18a, 18b of each bar have their respective slopes 18′ inclined in opposite directions. Thus, under a tensile effort, the locking elements 18a are moving towards the extremities of the body, thereby securing the clamping of the bars. Under a compression effort, the locking elements 18b are moving towards the center of the body, thereby securing the clamping of the bars.

The connection of the bars 2 is achieved by inserting the device lover the end 2′ of a first bar 2, said bar end 2 being received by the cavity 12 between the locking element 18 and the screws 16. A second bar 2 is then inserted into the other side of the device 1. The device can now be oriented in the radial direction deemed most suitable either for access purpose or for space optimization. The pushing means 22 may then be used to reduce the clearance between the bars 2 and the device 1. The screws 16 are finally torqued so that they press the bar 2 against the locking elements 18 and themselves penetrate into the surface of the bars 2.

When the bars 2 are pulled by application of a tensile load, the initial resistance comes from the gripping effect between the screws 16 and the locking elements 18. As the load increases, the locking elements 18 move along the slopes 12′ of the body 10, and further lock the bar ends 2′ inside the cavity, thereby greatly improving the tensile performance: the stronger the pull on the bars, the stronger the lock.

Claims

1. A device for connecting bars end-to-end, said device comprising: a hollow body having an internal cavity with at least one bar insertion opening and a longitudinal axis extending through said at least one insertion opening, said internal cavity having at least one slope inclined relative to a longitudinal axis of said hollow body;a plurality of radially-adjustable clamping elements mounted on said hollow body; andat least one locking element movably arranged inside said hollow body, said at least one locking element having an inclined face matching said at least one slope of said internal cavity and a gripping face having at least one protrusion.

2. The device according to claim 1, wherein said internal cavity of said hollow body has at least two slopes inclined relative to the longitudinal axis of said hollow body, said at least two slopes being inclined in opposite directions.

3. The device according to claim 1, wherein said gripping face is generally parallel to the longitudinal axis of said hollow body.

4. The device according to claim 1, wherein said internal cavity of said hollow body has a cross-section area increasing from a minimum at one end of said internal cavity to a maximum at a middle of said internal cavity and decreasing from said maximum at said middle of said internal cavity to a minimum at an opposite end of said internal cavity.

5. The device according to claim 1, wherein said internal cavity of said hollow body has a cross-section area decreasing from a maximum at one end of said internal cavity to a minimum at a middle of said internal cavity and increasing from said minimum at said middle of said internal cavity to a maximum at an opposite end of said internal cavity.

6. The device according to claim 1, wherein said radially-adjustable clamping elements have a designated preferential location of failure.

7. The device according to claim 1, further comprising: stop means provided in said internal cavity of said hollow body.

8. The device according to claim 2, wherein said at least one locking element has a radial thicknesses to accommodate bars of different sizes.

9. The device according to claim 1, further comprising: pushing means for pushing said at least one locking element from outside of said hollow body.

10. The device according to claim 1, wherein said at least one locking element having an end chamfered in order to reduce maximum height thereof.

11. The device according to claim 1, wherein said hollow body has at least one external face being comprised of ribs or grooves.

12. The device according to claim 1, further comprising: a corrosion-protection substance poured or injected inside said hollow body.

13. The device according to claim 1, further comprising: a binding substance poured or injected inside said hollow body.

14. A method of connecting bars end-to-end, said method comprising: inserting bars into a device comprised of a hollow body having an internal cavity with at least one bar insertion opening and a longitudinal axis extending through said at least one insertion opening, said internal cavity having at least one slope inclined relative to a longitudinal axis of said hollow body; a plurality of radially-adjustable clamping elements mounted on said hollow body; at least one locking element movably arranged inside said hollow body, said at least one locking element having an inclined face matching said at least one slope of said internal cavity and a gripping face having at least one protrusion; and stop means provided in said internal cavity of said hollow body, said bars being inserted until contacting said stop means; andtightening said radially-adjustable clamping elements until ends of said bars are forced against said gripping face, said radially-adjustable clamping elements being locked into a surface material of said bars, said at least one locking element being further forced against said bars when said bars are subjected to a tensile load.