Wire Binding Machine

The present invention relates to a wire binding machine according to the preamble of claim.

Automatic wire binding machines for applying a wire in one or more loops around an object or a bundle of objects, drawing the wire tightly around the object/bundle and thereafter tying partly overlapping wire portions together in order to secure the wire around the object/bundle are known in many different configurations.

A wire binding machine according to the preamble of claimis previously known from EP 2 578 498 B1. The wire binding machine disclosed in EP 2 578 498 B1 comprises a rotatable twisting head provided with two gripping members, which are individually moveable from a retracted wire releasing position to an advanced wire gripping position against the action of a spring force from a respective spring member. The actuators for moving the gripping members from the wire releasing position to the wire gripping position are not described in closer detail in EP 2 578 498 B1, but a hydraulic or pneumatic actuation of the gripping members is suggested in EP 2 578 498 B1. When implementing a wire binding machine of the type disclosed in EP 2 578 498 B1, the obvious choice for a person skilled in the art would therefore be to provide each gripping member with its own actuator in the form of a hydraulic or pneumatic cylinder mounted in the rotatable twisting head.

The object of the present invention is to achieve a further development of a wire binding machine of the type described above in order to provide a wire binding machine with a configuration which in at least some aspect offers an advantage as compared to this previously known wire binding machine.

According to the invention, this object is achieved by means of a wire binding machine having the features defined in claim.

The wire binding machine according to the present invention comprises:

The twisting device of the wire binding machine further comprises:

The above-mentioned sequential movements of the second gripping member and the first gripping member implies that the second gripping member is moved from its wire releasing position to its wire gripping position in a first step, when the wire is to be retracted and drawn tightly around the objects to be bound, whereupon the first gripping member is moved from its wire releasing position to its wire gripping position in a subsequent second step, when the twisting head is to be rotated in order to achieve a twisting together of the wire portions received in the first and second wire guide channels in the twisting head.

When a gripping member is in its wire releasing position, the wire is free to pass through the wire guide channel associated with the gripping member and may be released from this wire guide channel. When a gripping member is in its wire gripping position, the wire is retained in the wire guide channel associated with the gripping member and prevented from being released from this wire guide channel. In the wire binding machine of the present invention, the prevailing position of each individual gripping member, i.e. whether the gripping member is in the wire releasing position or in the wire gripping position, is determined by the rotary position of the second drive member in relation to the twisting head, wherein the movement of the second drive member between its different rotary positions in relation to the twisting head is controlled by the second electric motor. Thus, no hydraulic or pneumatic cylinder needs to be arranged in the twisting head in order to control the movement of the gripping members from the wire releasing position to the wire gripping position, which facilitates the construction of the interface between the twisting head and the surrounding housing since no rotary fluid seals will be required at this interface when no hydraulic or pneumatic cylinder is arranged in the rotatable twisting head.

In this description and the subsequent claims, the “front end” of the twisting head refers to the end of the twisting head that faces the space configured for receiving one or more objects to be bound.

According to an embodiment of the invention, the first gripping member and the second gripping member are both configured to be in its wire releasing position when the second drive member is in the rotary starting position in relation to the twisting head, wherein the motion transferring mechanism is configured:

Another embodiment of the invention, is characterized in:

Thus, the first and second electric motors jointly rotate the twisting head during the initial phase of the rotary movement of the twisting head when the cutting of the wire is effected at the interface between the outlet opening of the wire inlet channel in the housing and the inlet opening of the first wire guide channel in the twisting head. During this initial phase of the rotary movement, a comparatively high torque is required for rotating the twisting head. When the wire has been cut at said interface, a much lower torque is required for rotating the twisting head in order to achieve the desired twisting together of the wire portions received in the first and second wire guide channels in the twisting head, which implies that this phase of the rotation of the twisting head in relation to the housing can be effected by the first electric motor without any further assistance of the second electric motor. By taking assistance of the second electric motor during the initial phase of the rotation of the twisting head in relation to the housing, the requirements on the power output of the first electric motor is reduced, which implies that the size and cost of the first electric motor can be reduced as compared to the case when the entire rotation of the twisting head in relation to the housing is effected only by the first electric motor.

According to another embodiment of the invention, the third transmission mechanism comprises a first torque transmitting member that is fixed to the second drive member and an associated second torque transmitting member that is fixed to the twisting head or to the first drive member, wherein the first torque transmitting member is configured to be in torque transmitting contact with the second torque transmitting member only when the second drive member is in said rotary end position in relation to the twisting head. Hereby, torque for assisting in rotating the twisting head may only be transmitted from the second drive member to the twisting head via the third transmission mechanism when the second drive member is in the above-mentioned rotary end position in relation to the twisting head, i.e. when the first and second gripping members have both been moved to the wire gripping position.

According to another embodiment of the invention, one of the first and second torque transmitting members is formed by a shoulder at an end of a track in the first or second drive member or in the twisting head, wherein the other one of the first and second torque transmitting members comprises a projection that is received in and moveable along said track. The design of the third transmission mechanism is hereby simplified, at the same time as it will be capable of transmitting torque from the second drive member to the twisting head in an efficient and reliable manner when the second drive member is in the above-mentioned rotary end position in relation to the twisting head. However, the third transmission mechanism may as an alternative be designed in any other suitable manner.

As an alternative to a cutting of the wire by rotation of the twisting head in the manner described above, the cutting of the wire could be effected by a cutting member that is moveably mounted to the housing of the twisting device and actuated, for instance by means of an electric or hydraulic actuator, to cut the wire before the first electric motor is actuated to rotate the twisting head. In this case, the wire is consequently cut when the twisting head is standing still, which implies that no assistance from the second electric motor in the rotation of the twisting head is needed in this case.

The first gripping member is preferable moveable from its wire releasing position to its wire gripping position against the action of a spring force from a first spring member that is arranged in the twisting head, wherein the second gripping member in a corresponding manner is moveable from its wire releasing position to its wire gripping position against the action of a spring force from a second spring member that is arranged in the twisting head. Hereby, the force required for returning a gripping member from its wire gripping position to its wire releasing position can be provided in a simple manner by the spring member associated with the gripping member.

Furthermore, each one of the first and second gripping members is preferably linearly moveable between its wire releasing position and its wire gripping position in the axial direction of the twisting head, wherein the gripping member is in a retracted position in the twisting head in its wire releasing position and in an advanced position in the twisting head in its wire gripping position. In this case, the motion transferring mechanism is configured to transfer the rotary movement of the second drive member in relation to the twisting head into sequential translatory movements of the gripping members in a direction in parallel with the longitudinal axis of the twisting head and in parallel with the above-mentioned axis of rotation.

However, each one of the first and second gripping members may as an alternative be rotatably moveable in the twisting head between its wire releasing position and its wire gripping position, wherein the gripping member is in a first rotary position in the twisting head in its wire releasing position and in a second rotary position in the twisting head in its wire gripping position. In this case, the motion transferring mechanism is configured to transfer the rotary movement of the second drive member in relation to the twisting head into sequential rotary movements of the gripping members in the twisting head.

According to another embodiment of the invention, the motion transferring mechanism comprises:

Another embodiment of the invention, in which the first and second gripping members are linearly moveable between the wire releasing position and the wire gripping position in the axial direction of the twisting head, is characterized in:

Thus, in order to move a gripping member from its wire releasing position to its wire gripping position, the cam follower associated with the gripping member is in this case configured to push the gripping member via the intermediate compression spring, which implies that it will be possible for the gripping member to assume different end positions in its wire gripping position in dependence on the diameter of the wire presently used. Hereby, wires of different diameters can be used in the wire binding machine without requiring any adjustment of the gripping members.

As an alternative to cam mechanisms of the type described above, the motion transferring mechanism may comprise any other suitable type of mechanisms, such as for instance gear mechanisms, for transferring the rotary movement of the second drive member in relation to the twisting head into the desired movements of the first and second gripping members.

Other favourable features of the wire binding machine according to the invention will appear from the dependent claims and the description following below.

A wire binding machineaccording to an embodiment of the present invention is illustrated in. The wire binding machinecomprises a wire guide track arrangement, by means of which a wire(see) may be guided in one loop or two continuous loops around a spaceconfigured for receiving one or more objects (not shown) to be bound. The guide track arrangementis of the type described in closer detail in EP 2 578 498 B1, the content of which being incorporated herein by reference. The guide track arrangementcomprises a guide plate, which extends in a curve around said space. Plate-shaped and curved first guide elementsare mounted to the guide plateon a first side thereof and corresponding plate-shaped and curved second guide elements (not shown) are mounted to the guide plateon the opposite side thereof. A curved first guide trackis formed between the guide plateand the first guide elementson one side of the guide platefor guiding the wirein a first loop around said space, and a curved second guide track (not shown) is formed between the guide plateand the second guide elements on the other side of the guide platefor guiding the wirein a subsequent second loop around said space. Guide rollersare rotatably mounted between the guide plateand each guide element. These guide rollersare distributed along each guide track.

The wire binding machinemay as an alternative be provided with a guide track arrangement configured to guide a wire in only one loop around a spaceconfigured for receiving one or more objects to be bound.

In the illustrated embodiment, retainer unitsare mounted to the guide platein order to retain and subsequently release the wire during the tightening of the wirearound one or more objects. The design and functioning of these retainer unitsis described in closer detail in EP 2 535 278 B1.

A twisting deviceis located between the ends of the guide plate. This twisting devicecomprises a housingand a twisting headrotatably mounted in the housing, wherein the twisting headis rotatable in relation to the housingabout an axis of rotation. The twisting headis rotatable by means of a first electric motorin order to bind partly overlapping wire portions of the wiretogether by twisting to thereby secure the wire in one or two loops around one or more objects received in the above-mentioned space.

The twisting headis provided with:

In the illustrated embodiment, the twisting headis also provided with a third wire guide channelwhich extends across the twisting head at the front end thereof alongside of at least a part of the first and second wire guide channelsand in the area between them. The third wire guide channelin the twisting headmay of course be omitted if the wire binding machineis designed for securing a wire in one single loop around one or more objects to be bound.

The first and second gripping membersare individually moveable in the twisting headbetween a wire releasing position, in which the wireis free to pass through the associated wire guide channeland may be released from it, and a wire gripping position, in which the wireis retained in the associated wire guide channelby clamping and prevented from being released from it. In the illustrated embodiment, each gripping memberis linearly moveable between its wire releasing position and its wire gripping position in the axial direction of the twisting head, wherein the gripping memberis in a retracted position in the twisting headin its wire releasing position and in an advanced position in the twisting headin its wire gripping position. Thus, in this case, each gripping memberis moveable from its wire releasing position to its wire gripping position by a movement towards the front end of the twisting headin parallel with the above-mentioned axis of rotation.

In the illustrated embodiment, each gripping memberis moveable from the retracted wire releasing position to the advanced wire gripping position against the action of the spring force from a spring memberand moveable in the opposite direction from the advanced wire gripping position to the retracted wire releasing position by the spring force from this spring memberThus, the spring memberconstitutes a return spring for the associated gripping member

The first wire guide channelhas an inlet openingat a first end and an outlet openingat the other end. The inlet openingis provided in an outer peripheral surface of the twisting headand connected to an outlet openingof a wire inlet channelthat extends through a part of the housing. At least one cutting edge,is provided at the interface between the outlet openingof the wire inlet channeland the inlet openingof the first wire guide channeland configured to cut off the wireat this interface when the twisting headis rotated in relation to the housing. If only one such cutting edge is used, this cutting edge may be provided in the twisting headat the inlet openingof the first wire guide channelor in the housingat the outlet openingof the wire inlet channel. However, there are with advantage two co-operating cutting edgesat this interface. In the illustrated embodiment, a first cutting edgeis formed in the twisting headat the inlet openingof the first wire guide channeland a second cutting edgeis formed in the housingat the outlet openingof the wire inlet channel. When the twisting headis rotated in relation to the housing, the first cutting edgeis moved towards the stationary second cutting edgeto thereby cut through the part of the wirelocated between these cutting edgesand cut off the wire at the interface between the first wire guide channeland the wire inlet channel.

The part of the first wire guide channelclosest to the inlet openingis covered by a structural partwhich forms a counter member for the first gripping memberThe remaining part of the first wire guide channelis not covered and consequently open towards the front end of the twisting head. The outlet openingof the first wire guide channelis connected to a guide grooveprovided in the housing. Through this guide groove, the leading end of the wireis directed from the first wire guide channeltowards the first guide trackof the guide track arrangement.

The second wire guide channelhas an inlet openingat a first end. A stop surface (not shown) is provided at the other end of the second wire guide channelIn the illustrated embodiment, the second wire guide channelis provided with an outlet opening(see) in an outer peripheral surface of the twisting head, wherein said stop surface is provided on a part of the housingfacing said outlet opening. As an alternative, the stop surface could be integrated in the twisting headand form an end surface in the second wire guide channelIn the latter case, the second wire guide channelwould lack said outlet openingThe part of the second wire guide channelclosest to the stop surface is covered by a structural partwhich forms a counter member for the second gripping memberThe remaining part of the second wire guide channelis not covered and consequently open towards the front end of the twisting head. The inlet openingof the second wire guide channel is connected to a guide grooveprovided in the housing. Through this guide groove, the leading end of the wireis directed into the second wire guide channel

The third wire guide channelhas an inlet openingat a first end and an outlet openingat the other end, as illustrated in. The third wire guide channelis not covered and consequently open along its entire length towards the front end of the twisting head. The inlet openingof the third wire guide channel is connected to a guide grooveprovided in the housing. Through this guide groovethe leading end of the wireis directed into the third wire guide channelThe outlet openingof the third wire guide channel is connected to another guide grooveprovided in the housing. Through this guide groovethe leading end of the wireis directed from the third wire guide channeltowards the second guide track of the guide track arrangement.

The wire binding machinealso comprises a feeding device(see) for feeding the wireinto said wire guide track arrangementand along the wire guide track arrangement in one or two loops around said spaceand subsequently retracting the wire to draw it tightly around one or more objects received in said space. The feeding deviceis with advantage provided with an electric or hydraulic motorfor feeding and pulling the wire. At the beginning and at the end of each loop, the leading end of the wireis guided into one of the wire guide channelsof the twisting head.

The guide track arrangementcomprises a guiding device, by means of which the leading end of the wireis guidable into the third wire guide channelof the twisting head when the wire has been guided by the guide track arrangementin a first loop around the above-mentioned spaceand into the second wire guide channelof the twisting head when the wire has been guided by the guide track arrangement in a subsequent second loop around said space. The design and functioning of this guiding deviceis described in closer detail in EP 2 578 498 B1.

The twisting devicecomprises a first drive member, which is non-rotatably fixed to the twisting headand which is configured to be rotated by the first electric motorin order to rotate the twisting head. Driving torque for rotating the first drive memberin relation to the housingis transmitted from the first electric motorto the first drive memberthrough a first transmission mechanism

The twisting devicefurther comprises a second drive member, which is rotatably mounted in the housingso as to be rotatable in relation to the housing about the axis of rotation, wherein the second drive memberis rotatable in relation to the twisting headabout the axis of rotationfrom a rotary starting position to a rotary end position by means of a second electric motor. Driving torque for rotating the second drive memberin relation to the twisting headis transmitted from the second electric motorto the second drive memberthrough a second transmission mechanism

Each drive member,preferably has the form of an externally toothed wheel or ring, wherein the transmission mechanismassociated with the drive member comprises a toothed drive belt or a gearthat is in driving engagement with the drive member. In the illustrated embodiment, each drive member,has the form of an externally toothed wheel, which is in engagement with a gearincluded in the associated transmission mechanismThe gearsare non-rotatably fixed to a respective shaftwhich in its turn is rotatably mounted to the housingand rotatable by the associated electric motor,.

In the illustrated embodiment, the first drive memberis arranged at the rear end of the twisting headand the second drive memberis arranged between the first drive memberand a rear wallof the housing, as illustrated in. In this case, the first and second drive members,are arranged side by side with a rear faceof the first drive memberfacing a front faceof the second drive member. In the illustrated example, the second drive memberis rotatably mounted to a shaft, which is fixed to the first drive memberand extends rearwardly from the rear facethereof. The second drive membercould as an alternative be rotatably connected to the twisting headin any other suitable manner, for instance by being mounted to a shaft that forms part of the twisting head.

In the illustrated embodiment, the unit formed by the twisting headand the two drive members,is rotatably mounted to the housingby means of a first rolling bearingfor instance in the form of a ball bearing, provided at the front end of the twisting headand a second rolling bearingfor instance in the form of a ball bearing, provided between the rear wallof the housingand a shaftthat is fixed to the second drive memberand extends rearwardly from the rear facethereof.

A motion transferring mechanism is configured to transfer a rotary movement of the second drive memberin relation to the twisting headfrom the above-mentioned rotary starting position to above-mentioned rotary end position into sequential movements of the second gripping memberand the first gripping memberfrom its wire releasing position to its wire gripping position. The first and second gripping membersare both configured to be in the wire releasing position when the second drive memberis in the rotary starting position in relation to the twisting head, wherein the motion transferring mechanism is configured:

In the illustrated embodiment, the motion transferring mechanism comprises:

The first gripping memberis moveable from its wire releasing position to its wire gripping position under the effect of the cam memberand the first cam follower, and the second gripping memberis moveable from its wire releasing position to its wire gripping position under the effect of the cam memberand the second cam follower

Each cam followeris configured to rotate together with the twisting headbut is moveably mounted to the twisting headsuch that it is moveable in relation to the twisting head under the effect of the cam member. In the illustrated embodiment, the cam followersextend through a respective though hole in the first drive memberand are partly received in a respective bore in the twisting head.

The illustrated cam memberhas the form of a ring, wherein the above-mentioned first and second guide surfacesare provided on a front face of the ring-shaped cam memberfacing the rear end of the twisting head. The cam membermay of course also have any other suitable design. In the illustrated example, a first slide bearingin the form of a cylindrical bushing is provided between an outer peripheral surface of the shafton the first drive memberand the inner peripheral surface of the ring-shaped cam memberand a second slide bearingin the form of a cylindrical bushing is provided between an outer peripheral surface of the shafton the first drive memberand an inner peripheral surface of the shafton the second drive member.

Each cam followeris with advantage provided with a rotatably mounted roller, through which the cam followeris in contact with the associated guide surfaceon the cam member and which is configured to roll along this guide surface when the cam memberis rotated in relation to the twisting headtogether with the second drive member.

In the illustrated embodiment, each cam followeris moveable in relation to the associated gripping memberin the axial direction of the twisting head, wherein the motion transferring mechanism comprises a first compression springacting between the first cam followerand the first gripping memberand a second compression springacting between the second cam followerand the second gripping memberThe second cam followeris configured to exert a pushing force on the second gripping membervia the second compression springwhen the second drive memberis moved by the second electric motorfrom said rotary starting position to said intermediate rotary position. Thus, the second cam followerwill push the second gripping memberfrom its wire releasing position to its wire gripping position via the second compression springIn a corresponding manner, the first cam followeris configured to exert a pushing force on the first gripping membervia the first compression springwhen the second drive memberis moved by the second electric motorfrom said intermediate rotary position to said rotary end position. Thus, the first cam followerwill push the first gripping memberfrom its wire releasing position to its wire gripping position via the first compression spring