The invention relates to a device and to a method for producing clamps bent from wire sections, in particular surgical clamps, with a bending device for bending a wire section.
Numerous realizations of such devices are known. The problem here, however, is that the wire section can be displaced or twisted when acted upon by the bending device such that the clamps are subject to comparatively large production tolerances. Even when the wire section is severed from a fairly long piece of wire, corresponding positional displacements can occur resulting in measurement inaccuracies.
U.S. Pat. No. 5,060,468 shows and describes a device together with a method where a prefabricated wire section is insertable into a holder. The free ends of the wire section are then acted upon by a severing device and at the same time are bent and shortened. The wire section is certainly held in a clamping manner in this case, which reduces the risk of positional displacements, but as a result of shortening the free ends of the wire section, a large amount of scrap material is generated with each individual clamp.
Consequently, the object consists in creating a device and a method of the type mentioned in the introduction, by way of which clamps with small production tolerances are able to be produced. In addition, no scrap material or only a little scrap material is to accrue.
The solution according to the invention consists with respect to the device in that a feed device for a wire is provided with a cutting device for severing a wire section from the supplied wire, that the cutting device comprises two cutting punches for cutting the wire, and that a holding device is provided for gripping and holding the wire section between the two cutting punches prior to severing the wire section and for positioning the severed wire section on a bending device as well as for supplying the wire section bent to form the clamp to a device for introducing the clamp into a cartridge or a clamp storage.
As the wire is already gripped prior to the severing in the region of the wire section to be severed and is held continuously during the severing and the bending until it is fed to the device for introducing the clamps into a cartridge or a clamp storage without the wire section or the wire section which is bent to form the clamp being released in the meantime, the wire sections can be severed and bent at a repeat accuracy of 1/100 millimeter. Slipping in the longitudinal direction or twisting is reliably avoided. In addition, unnecessary loss of material is avoided as the wire section which is severed by the cutting punches is bent to form the finished clamp without its length being shortened any further.
A preferred embodiment in this case provides that the holding device is realized in a tongs-like manner and comprises a holding region which is movable against a resetting force from a holding position into an open position. This makes it possible to fix the holding device on the wire section in a simple manner and inadvertent release is reliably avoided by means of the resetting force.
The bending device can comprise in particular an anvil as a forming element for the wire section which is mounted in a linearly displaceable manner between two pressing rollers which are each adjustable against a resetting force.
As a result, the wire section is able to be bent to form the clamp in a simple manner. The wire section, in this case, is placed by way of its central region, which forms the clamp back of the finished clamp, onto an end face of the anvil. As a result of the two free ends which protrude on both sides being acted upon, said free ends are bent by the pressing rollers and pressed against the longitudinal sides of the anvil. These bent ends of the wire section consequently form the legs of the finished clamp. The form of the finished clamp can be established as a result of the shaping of the anvil. For example, the end regions of the legs can be additionally bent inward as a result of a corresponding anvil form with a tapering region.
In addition, the bending device can comprise an anvil which comprises stop surfaces for the bent wire legs and pressing rollers which are assigned to said wire legs for shearing the wire legs against one another.
After the wire sections have been bent, the clamp can be placed onto a further anvil in order to deflect the wire sections out of the flat clamp plane and to fold them toward one another. This can be useful in particular in the case of clamps with long legs so that the free ends of the legs do not touch each another during the clamping operation, which can result in an incomplete clamping operation and in an insufficient hold.
It is also possible for the anvil of the bending device to comprise a circle-segment-shaped forming region for the wire section in order to be able to produce correspondingly formed clamps with a rounding.
For uniform and synchronous movement of the holding device and the anvil, it is expedient when the holding device is releasably connectable to the anvil of the bending device.
The feed device can comprise in particular a wire roll as a hopper for the wire to be supplied. This enables a large quantity of wire to be provided in a small space.
In order to eliminate curvatures from the wire unwound from the wire roll and to ensure that the wire is supplied in a straight form in the region of the cutting punches, the feed device can comprise a straightening mechanism with several guide rollers arranged on both sides of the wire for aligning the wire unwound from the wire roll.
Also for straightening the unwound wire, the feed device can comprise two clamping elements which are linearly displaceable in the advancing direction of the wire. A section of the wire is held in clamping manner by the two clamping elements which are spaced apart with respect to one another. One of the clamping elements is then moved away from the other clamping element by a small distance as a result of a linear displacement such that the spacing between the two clamping elements is increased. Where applicable, both clamping elements can also be moved in opposite directions. As a result, the wire section clamped between the clamping elements is straightened and possible curvatures eliminated.
The cutting punches can preferably comprise in each case an oblique cutting edge. As a result, the wire section can be severed such that the free ends of the wire section comprise a corresponding lead-in chamfer. Additional cutting operations at the ends of the wire section are consequently not necessary.
In order to be able to vary the orientation of the cutting edge in a simple manner, it is advantageous when the cutting punches are mounted in each case in a punch guide which is pivotable about an axis oriented in the longitudinal direction of the wire and/or can be arranged rotated by 180° with reference to the longitudinal direction of the wire.
A least one processing device for the wire or the wire section can be arranged upstream and/or downstream of the bending device. For example, material weakening can be introduced into the wire prior to the bending in order to enable simpler bending in this manner at said positions. In the case of a corresponding requirement for the finished clamp, the free ends of the wire section can also be processed, for example ground, sharpened or twisted. The processing device can also be realized for installing a marking, for example a bar code, a date code or an identity code. The marking, in this case, can be effected, for example, by means of laser engraving.
It can be expedient when a control device is provided for the bent wire section. In this case, in particular the form of the bent clamp and/or the spring force of the clamp legs can be checked.
A preferred embodiment provides that the device for introducing the clamp into a cartridge or a clamp storage mean comprises a slide for acting upon the clamp on the clamp rear thereof. As consequently the free ends of the clamp legs, which represent the most sensitive part of the clamp, are not acted upon, damage to them when the clamp is introduced is avoided in a reliable manner.
In this case, it is expedient when the slide is adapted to the shape of the wire section in the impact region. This enables reliable guiding of the clamp by the slide.
It can additionally be expedient when the slide is thinner in the impact region than the wire section to be acted upon. For example, the slide can be thinner than the wire section by between 0.01 mm and 0.1 mm. As a result, the slide can push the clamps into a cartridge or a clamp storage without itself impacting against the cartridge or the clamp storage.
In a preferred manner, a drive unit is provided for linear displacement of the slide.
The drive unit can comprise a force sensor and a control unit for controlling the slide in dependence on the sensor signals. Too strong an application of force at the drive unit can indicate, for example, a wrongly positioned clamp which cannot be introduced correctly into the cartridge or a clamp storage. In such a case, the drive unit can be stopped by the control unit in order to avoid damage to the device.
It is also possible for the drive unit to comprise a force-controlled coupling unit. In the case of too high an application of force, the coupling unit can disengage such that the slide is no longer driven. The coupling unit can be formed, for example, by spring clamping which slips in the event of too high a load.
In a preferred manner, the device for introducing the clamp into a cartridge or a clamp storage can comprise a housing with a guide for the slide and an insertion opening for inserting in each case one clamp.
In order to be able to fill the individual clamp receivers in a clamp storage or of a cartridge one after another by way of the device for introducing the clamps, it is expedient when a positioning device for positioning a clamp storage or a cartridge is provided upstream of the output-side end of the device for introducing the clamp into a cartridge or a clamp storage. Consequently, a clamp receiving means can be positioned in each case in front of the stationary device in order to introduce one clamp in each case into the clamp receiving means by way of the slide.
The individual components of the device (feed device, cutting device, holding device, bending device and device for introducing the clamps into a cartridge or a clamp storage) can be arranged in individual processing stations spaced apart from one another. In a preferred manner, the individual components of the device are arranged, however, in one common processing station. This enables the entire device to be designed in a compact and space-saving manner.
With regard to the method, the invention is characterized in that the wire section is cut off a wire and the free ends of the wire section are bent to form wire legs, that the wire section that is bent to form a clamp is introduced into a cartridge or a clamp storage, and that the wire section is gripped prior to severing and is held constantly during the severing and the bending.
The advantages that have already been explained in the case of the description of the device according to the invention are produced in this case.
The wire is preferably unrolled from a wire roll.
In this case, it is advantageous when the wire is aligned and/or stretched prior to the severing. As a result, possible bends are eliminated and the wire is aligned precisely in a straight manner prior to severing and bending to form the clamp, as a result of which the desired precision of the clamps is able to be achieved.
The bending of the wire section to form the clamp can be effected in a good and precise manner when the severed wire section is placed by way of its central region, which forms the clamp back of the finished clamp, onto an anvil and the anvil is moved through between two pressurized pressing rollers and, as a result, the wire regions protruding beyond the anvil are bent.
It can be expedient when the bent wire legs are bent out of the clamp plane and are sheared against one another. In particular in the case of clamps with long legs, this reliably avoids the wire legs touching each other at their ends and thus being able to impair reliable clamping.
The wire section can be processed upstream and/or downstream of the bending process. For example, material weakening can be introduced into the wire section or the wire ends can be ground or sharpened. It is also possible to install markings onto the wire section.
The invention is explained in more detail below by way of the drawings, in which, in part in schematic representations:
A device, given the overall reference of 1, for producing clamps 3 which are bent from wire sections 2 comprises, according to
In order to eliminate curvatures in the unwound wire 5, the feed device 4 comprises a straightening mechanism 8 with several guide rollers 9 which are arranged on both sides of the wire 5. Possible curvatures of the wire 5 are eliminated when the wire 5 runs through the guide rollers 9 which are arranged alternately on both sides of the wire 5.
After running through the straightening mechanism 8, the further conveyed wire 5 is gripped by two clamping elements 10. The left-hand clamping element 10 in
Both clamping elements 10 are then moved in a synchronous manner to the right such that a section of the wire 5 that was stretched beforehand is pushed to the right of the clamping elements 19 into the region of the cutting device 6. The clamping elements 10 are then opened and moved back into their starting position such that that they are able to hold a further region of the wire 5, which has run through the guide rollers 9 beforehand, in a clamping manner.
The cutting device 6 comprises two cutting punches 11 which are mounted in each case in a punch guide means 12, the wire 5 being guided in each case through an opening 13 (
Once the wire 5 has been fed to the cutting device 6, the wire 4 is gripped between the two cutting punches 11 by way of a holding device 14. Only then is the section of the wire 5 between the two cutting punches 11 severed from the supplied wire 5 as a result of actuating the cutting punch 11. As a result of the form of the cutting edge 15 of the cutting punch 11 (
The wire 5 can be guided by additional guide elements (not shown) inside the feed device 4. The position of the punch guide means 12 and consequently of the cutting punch 11 can be adjusted in the longitudinal direction of the wire 5 in order, on the one hand, to be able to cut off variously long wire sections 2 and in order, on the other hand, to enable unobstructed removal of a severed wire section 2 from the region between the two punch guide means 12.
The punch guide means 12 are held so as to be releasable in each case in holders 17 (
When other cutting angles or other cutting forms are desired, the punch guide means 12 can be exchanged by correspondingly developed examples.
It is also easy to see in
Once the wire section 2 has been severed, it is supplied with the holding device 14 to a processing device 19 (
According to
As shown in
According to
According to
As a result of displacing the slide 40 further in a linear manner, the clamp 3 is displaced out of the housing 36 and the device 33 (
Realizations would also be conceivable where a clamp 3 is held by the holding device 14 such that the holding device 14 is pivoted upward by 90° in relation to the representation shown. The base plate 37 and the cover plate 38 could then be realized without recesses 42.
It would also be conceivable to introduce the clamp 3 from the left side of the housing 36 in
Pushing a clamp 3 into a cartridge 34 is also shown in
A drive unit 46, which converts the rotary movement of a drive motor 47 into a linear movement for displacing the slide 40, is provided according to
As an alternative to this, clamps 3 can also be inserted into a clamp storage 35 according to
For example, a clamp storage 35, as shown in
Individual processing stations can also be effected at the same time, for example a clamp 3 can be inserted into a cartridge 34 whilst a new wire section 2 is being cut off and bent.
Twin machines, where individual processing steps are effected on multiple devices in parallel, are also conceivable.
Number | Date | Country | Kind |
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10 2013 004 652.1 | Mar 2013 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2014/000462 | 2/21/2014 | WO | 00 |