Object binding
An apparatus for tying a wire 46; 52 around one or more objects such as concrete reinforcing bars 2 is disclosed. It comprises means for passing the wire 46; 52 in a loop around the bars and a rotatable head 4 for twisting the ends of the loop together. The head 4 has at least one gripping means such as a variable force clutch 32 for gripping the wire, the gripping means being adapted to provide a variable gripping force so as to apply a predetermined tension to the wire during at least a first phase of twisting. Also disclosed is pre-feeding the wire between tying operations; conditioning the surface of the wire; and using the electrical conductivity of the reinforcing bars to verify that the bars are present before tying.
1. An apparatus for tying a wire around one or more objects comprising:
a wire feed roller for passing said wire in a loop around the one or more objects, and
a rotating and gripping mechanism for twisting the ends of said wire together, said rotating and gripping mechanism comprising a rotatable head arranged to rotate in order to twist the ends of the wire together and at least one gripper for gripping the wire so that the wire does not slip therethrough,
wherein the apparatus comprises a sprung housing, stand or frame for applying a resilient biasing force between the rotating and gripping mechanism and the one or more objects, wherein the sprung housing, stand or frame engages the one or more objects being tied such that the sprung housing, stand or frame applies the resilient biasing force between the rotating and gripping mechanism and the one or more objects while said wire is being twisted such that the rotating and gripping mechanism is drawn towards the one or more objects against said resilient biasing force.
2. The apparatus of claim 1 , wherein the sprung housing, stand or frame comprises a fixed portion and a moveable portion.
3. The apparatus of claim 1 , further comprising one or more rollers for altering the frictional properties of the surface of the wire and/or wherein the wire feed roller is arranged to alter the frictional properties of the surface of the wire.
4. The apparatus of claim 3 , wherein said one or more rollers and/or the wire feed roller is adapted to increase the friction of the surface of the wire by altering the texture of the surface of the wire.
5. The apparatus of claim 4 , wherein the one or more rollers and/or the wire feed roller comprises teeth for serrating the surface of the wire.
6. The apparatus of claim 3 , wherein one or more of the one or more rollers and/or the wire feed roller has a surface adapted to impart a texture to the surface of the wire.
7. The apparatus of claim 3 , wherein the one or more rollers comprises a bending roller.
8. The apparatus of claim 1 , wherein the wire feed roller is provided on the rotatable head.
9. The apparatus of claim 1 , wherein the rotatable head is arranged to return the rotatable head to a predetermined parking position or one of a plurality of predetermined parking positions.
10. The apparatus of claim 1 , wherein the rotatable head is configured to apply a torque sufficient to shear the wire as the rotatable head begins to turn.
11. The apparatus of claim 1 , wherein the apparatus further comprises a guiding surface arranged to deflect the wire as it is being twisted so that the ends of the wire finish pointing at least partially in a direction of the one or more objects being tied.
12. The apparatus of claim 1 , wherein the apparatus further comprises a cutter for cutting the wire, wherein the wire feed roller is arranged to pre-feed a length of wire beyond the cutter at the end of a tying operation.
13. The apparatus of claim 1 , wherein the wire feed roller and a wire receiving surface are arranged to pass the wire imparted with an arcuate set in the loop around the one or more objects from the wire feed roller to the wire receiving surface.