Tool device for high-speed machine-working

The present invention relates to a tool device for high-speed crosscutting, comprising a striking unit, a tool housing, a damper unit, a movable crosscutting tool and a fixed crosscutting tool. The tool housing has at least two curved supporting surfaces for the moveable crosscutting tool. The supporting surfaces have the same radius. A recess is provided between the supporting surfaces. The recess is provided for a striking piston in the striking unit. Also provided is a crosscutting tool for high-speed machine-working.

TECHNICAL FIELD

The invention relates to a tool device for high-speed crosscutting, comprising a striking unit, a tool housing, a damper unit, a movable crosscutting tool and a fixed crosscutting tool. The invention also relates to a crosscutting tool for high-speed machine-working.

PRIOR ART

By virtue of, for example, U.S. Pat. No. 3,735,656, a tool device of the above description is previously known. The use of such a tool device to cut rod-like material by virtue of high energy-supply speed is therefore previously known. Despite a number of potential advantages with the method, it is not widespread and established within manufacturing industry. One of the reasons why this technique has not become established on a larger scale appears to be that the tool configuration was deficient and led to undesirable production stoppages. Just such a deficiency is that it was often not possible to obtain sufficiently good precision in terms of the alignment of the fixed and the movable tool. Common to conventional tool configurations is that the crosscutting tools, at least the movable crosscutting tool, was rectangular. For production engineering reasons, there has to be a certain clearance between the sides of the tools and the tool housing, both in the lateral direction and in the vertical direction. The measuring accuracy in respect of the centre hole for the material relative to the sides of the tool also demands a certain tolerance. All in all, this means that the position of the centre hole for the two tools is not certain to be exactly mutually aligned, which poses a problem when material is to be fed through the tool between each cut. Another deficiency is that known constructions used a type of helmet for transmitting the impact energy from the striking piston to the movable crosscutting tool, which is an undesirable construction from many aspects. Another drawback is that known constructions require removal of the tool housing in case of tool change and thereby gave undesirably long set-up times for the machine.

SUMMARY OF THE INVENTION

An object of the present invention is to eliminate or at least minimise some of the aforementioned problems, which is achieved with a tool device for high-speed crosscutting, comprising a striking unit, a tool housing, a damper unit, a movable crosscutting tool and a fixed crosscutting tool, characterised in that the tool housing has at least two curved supporting surfaces for the movable crosscutting tool, which supporting surfaces have the same radius, and in that between the said supporting surfaces there is a recess for a striking piston belonging to the striking unit.

Owing to the invention, very good precision in terms of alignment of the fixed and movable tool is achieved. In addition, the configuration means that simpler methods in production-engineering terms can be used to obtain high measuring accuracy. The invention further means that the tools can automatically be centred in the lateral direction, also, when they are applied to the tool housing in the vertical direction, which is a great advantage.

According to preferred aspects of the invention, it is possible to make the tool housing so strong that the conventionally used “helmet” can be eliminated, so that the striking piston can strike directly against the movable crosscutting tool. According to another aspect, it means that the fixed tool is pressed against one side inside the recess in the tool housing so that a mute response is obtained upon the blow, which aspect is further improved by the fact that the tool housing is of elongated configuration in the direction of impact, and without undesirable kerfs, which were often the case in previously known constructions. Another potential advantage is that the tool housing can be configured such as to enable a very compact unit for tool return and damping of surplus energy to be placed in direct connection with the movable crosscutting tool, whereby a constantly pressurised return piston can be brought to act directly against the movable crosscutting tool so that the time between the blows can be made extremely short.

DETAILED DESCRIPTION

FIG. 1shows in perspective view obliquely from above a preferred module unit of a tool device according to the invention. The tool device comprises a striking unit10, a tool housing20and a damper30. Inside the tool housing20there are disposed a movable crosscutting tool40and a fixed crosscutting tool50. A striking piston11, which is supported and driven by a driving portion of the striking unit10, can administer to the movable crosscutting tool40from below an upwardly directed blow with high kinetic energy, in a manner which is known per se, the fixed crosscutting tool50exerting a detaining force upon the workpiece to be cut (not shown). The damper30is arranged to brake the striking motion of the movable crosscutting tool40following completion of the cutting. The striking unit10and the damper30, with associated damper housing34, hydraulic block31and pressure accumulator32, do not form part of this invention and will therefore not be described in depth. It can however be mentioned that the projecting wheeled member33on the damper30constitutes an adjusting mechanism for setting the desired damping, as well as that the cylindrical portion12projecting downward in the figure on the cylinder housing10constitutes a position indicator housing.

According to the illustrative embodiment shown, the tool module shown inFIG. 1andFIG. 2is arranged to cut cylindrical wire. For the purpose of guiding the wire which is to be cut, there is a wire-guiding unit60, which is centrally placed on the back of the tool housing20(seeFIG. 2). The tool housing20consists of a solid base element21on top of which there is a cover22. The cover22is firstly fixed to the base unit21by means of screws220at its rear edge and secondly by means of stud bolts221at its front edge. These stud bolts also hold together other parts of the module, i.e. also the striking unit10and a base plate23belonging to the tool housing. The base plate23comprises a suspension arrangement23, which enables quick and simple fitting and removal of the entire tool module.

The suspension arrangement on the said base plate23, is solid and has a width exceeding the width of the actual tool housing20. Projecting portions23A,23B are thus formed, on both sides of the tool housing20. In each of these projecting portions23A,23B there are two holes230,231and233,234respectively, in which fitting bolts235-238are disposed. On these fitting bolts there are rubber pads239A-242A. The fitting bolts235-238are designed to be fitted into matching holes in the actual crosscutting machine (not shown), whereby the tool device is fixed in the horizontal plane in the machine. Owing to the rubber pads, a certain resilience is allowed in the vertical direction, giving both sound insulation and vibration damping. Thanks to the solution involving fitting bolts, the facility is obtained for very fast and smooth changing of the entire module unit, whereby costly stoppages can be eliminated. In known devices, the entire unit cannot be changed, according to requirement, without the need for a time-consuming removal of various component parts.

FIG. 3shows essential parts of a preferred embodiment of certain essential parts of a tool housing20according to the invention. It can be seen that the base element21consists of a solid piece of relatively, large height H and also of relatively large thickness T. Up on its end face210there are threaded holes211for fastening of the cover22. In addition there are guide pins212arranged for exact positioning of the cover22. On the front face of the base element there are arranged two heel-shaped portions213and214, so that on each inwardly directed end face213A and214A there are formed parallel guide surfaces, which normally are positioned vertically, so that these guide surfaces213a,214acan prevent rotation of the movable crosscutting tool40. To each of the heels213and214there is fastened a respective fixing member24and25. These fixing appliances24,25, like the heels213,214, are configured wholly symmetrically with respect to a vertical plane of symmetry coinciding with the centre line C for the wire which is to be cut. Each fixing appliance24,25is fixedly anchored to the respective heel213by means of three screws241. The fixing appliance24has its lower surface level with the base unit21and extends right up to somewhat directly below the respective upper end face of the heels213,214. From an essentially rectangular main body part in the fixing appliance24, supporting portions242and252project in toward the centre line C. Parallel with the centre line C, in each of the said supporting portions242,252, there are recesses243and253. In the said recesses243,253, resilient locking appliances244and254respectively are disposed (seeFIG. 8). With the aid of these locking appliances244,254, a supporting hatch26is fixed in the vertical direction. In the lateral direction and outward/forward, the hatch26is fixed by the respective fixing appliance24,25and held inwardly in place by means of outwardly directed surfaces213B,214B of the heel members213,214. In the centre of the supporting hatch26there is a recess260(shown previously inFIG. 5). In the bottom of the base element21are disposed guide pins215designed to fix the base element21in the bottom plate23to the tool device. In addition,FIG. 3shows that on one face of the base element21there is a lubricating hole216, for lubricating slide surfaces in the crosscutting device. Finally, inFIG. 3, a recess217is discernible in the bottom portion of the base unit21, which recess217has a U shape and provides space for the striking piston11to penetrate up toward the movable crosscutting tool40.

FIG. 4shows a front view of the unit according toFIG. 3. It can be seen that the hatch at the ends of the front face is provided with edge portions26A,26B, which interact, with fit, with opposite-facing side faces of the supporting portions242,252. Unlocking of the locking appliances244,254allows displacement of the hatch26in the vertical direction, i.e. parallel with the guide surfaces26B,26A. It can further be seen that the recess260disposed in the central part of the hatch26has an upper portion26D which extends through the whole of the hatch26. Downward in the direction out toward the front face from the said through-hole there is a downwardly directed recess262, whereby a sloping bottom portion262A is formed. In the extension of the through-hole26, concentrically positioned, there is a through-hole41, in the movable crosscutting tool40, and behind this a through-hole612in a guide sleeve61(seeFIG. 5). Emerging above the upper edge of the hatch26there is an opening216A of the lubricating duct216, so that lubricant can flow down toward purpose-made slide surfaces. In extension of the recess217for the striking piston11, the bottom edge44A of the movable crosscutting tool40is discernible. It is evident that the bottom edge forms a plane edge face42, which is designed to receive the blow from the piston11. It can further be seen that adjoining edge faces43a,43bconstitute curved surfaces. These curved surfaces are configured with a given radius R. The same radius R is found in the surface218, present in the base element21, which is borne against by the radius-possessing lower surfaces of the crosscutting tools.

FIG. 5shows a section along the line A-A inFIG. 4. It can be seen that the control unit60comprises an inner guide sleeve61, which is centred in relation to the centre line C for the wire which is to be cut. The guide sleeve61is, in turn, fixed inside a tensioning sleeve62, concentrically. For the purpose of being able to fix the guide sleeve61inside the tensioning sleeve62, the guide sleeve61is provided with a beveled surface610, designed to interact with a stop screw620which, threaded, is disposed in a hole621at the end of the tensioning sleeve62. At the other end of the tensioning sleeve62there is a flange-like portion622, which is wholly matched to the configuration of the hole219present in the base element21. This hole is wholly cylindrical, with a certain radius R. Corresponding to this radius R is the radius R found in the curved edge portions, for example43A,43B of the striking tools40,50(to be described in greater detail below).

The flanged portion622of the tensioning sleeve62has a diameter which is essentially consistent with the diameter inside the hole219through the base element21. For positioning of the tensioning sleeve and the flange622, and hence the positioning surface622A of the flange, a pressure screw63is provided, which is sleeve-shaped and is arranged concentrically on the outside of the tensioning sleeve62. In the outer surface of the pressure screw63there is a thread630. This thread630is designed to interact with a lock block64and a correspondingly threaded through-hole640in the lock block64. The lock block64is fixed to the base element21by fixing screws (seeFIG. 8). By providing the lock block64with a through-slot641and a threaded joint642interacting therewith, it is possible to adjust the clamping force from the thread640against the pressure screw63to the required level, from being able to run very easily to being able to fix the pressure screw63by clamping/friction force. By threading the pressure screw63to the desired position, the desired positioning of the guide surface622A of the tensioning sleeve62is therefore obtained. At the same time, an exact centring of the centre line C through the hole612in the guide sleeve is obtained by the construction (it will be realised that normally the diameter of the through-hole612is chosen to be larger than the holes41,51in the crosscutting tools40,50).

It can further be seen fromFIG. 5that the fixed crosscutting tool50consists of two concentrically arranged sleeve-shaped parts52,53. The inner sleeve is made in a material (expediently hard metal or hardened high-speed steel), the properties of which, above all, are optimised with respect to wearing properties. The outer sleeve53is chosen in a material which primarily is optimised with regard to being able to absorb large instantaneous force shocks without risk of plastic deformation or cracking (for example, tool steel with high impact strength). Correspondingly, the movable tool40is also composed of an inner42and an outer43sleeve-shaped part. Through the inner sleeve-shaped element42and52, holes41and51respectively are made, the diameter d of which is somewhat larger than the wire diameter dTof the wire which is to be cut. The clearance should in many applications be kept to about 0.03-0.05 mm, but very often there is a need for greater clearance in case of increasing diameter dT. Other configurations of the crosscutting tools are described in greater detail in connection withFIG. 10andFIG. 11.

The fixed crosscutting tool50thus bears with its inner surface against the guide surface622A of the tensioning sleeve62. The fixed tool50is positioned inside the cavity219in the base element21so that it is both rotationally secure and also, moreover, in the transverse direction fixed in relation to the base element21. Since the tool50is provided with four curved edge faces53A,53B,53C,53D which are exactly matched to the radius R of the through-hole219, an exact positioning and alignment of the tool will be obtained. The centre line C for the wire will therefore coincide with the centre line for the tool50. Correspondingly, an identical positioning of the movable tool40is achieved by virtue of the latter, with its lower, radius-possessing surfaces43A,43B interacting with/bearing against the radius-possessing surface218of the part222of the base element which projects forward at the bottom and in which the U-shaped opening for the striking piston11is disposed. It can be seen fromFIG. 5that the opposite-facing surfaces of the movable40and the fixed50tool are designed to slide relative to each other, which must occur in connection with cutting of a wire which has penetrated into the through-hole41of the movable tool40. At the same time, a guidance takes place of the movable tool40on its opposite side40A, by means of an inwardly directed surface26C of the hatch26. For the purpose of being able to prevent rotation of the fixed tool50, a rotation lock29is provided, consisting of a rod-shaped member whose upper surface29A is designed to interact with a plane surface54A of the fixed tool50.

FIG. 6shows a section along the line F-F inFIG. 4. It can here clearly be seen that the edge portions53C,53D in the section for the fixed tool50have exactly the same fit as the circular surface218of the through-hole219in the base element21. It can also be seen that the movable tool40in the same way interacts with one of its radius-possessing surfaces43ain the same section and against a surface218with the same radius R, so that an exact positioning/alignment is obtained. In the figure, it can also be seen that an inspection hole261is provided through the hatch26.

FIG. 7shows a section along the line G-G inFIG. 4. It can be seen that the fixing appliance24, in addition to the screw elements241, is also fixed by guide pins243. It can further be seen that the heel213, according to a preferred embodiment, constitutes a part integrated with the base elements21.

FIG. 8shows a section along the line E-E inFIG. 4. It can herein be seen that the hatch26is configured with a non-continuous recess269, designed to interact with the end254A of a lock appliance254. This consists, in turn, of a pin-shaped element254B, which, at its other end, has been provided with a knob254C. A spring element256is disposed in an inner cavity246in the fixing appliance24, the end254A of the lock appliance endeavouring to jut out of the cavity246, whereby the hatch26can easily be fixed in the vertical direction by snapping in place. Also shown is a threaded hole223, designed for fastening of the base element21against the bottom plate23.

FIG. 9shows a view from below of the element according toFIG. 4. It can be seen that the hatch26has a cross-sectional form in the horizontal plane which generates the guide surfaces26E,26F for the movable crosscutting tool40in the lateral direction. Also evident are the U-shaped recess217in the base element21and the recess211for the through-passing stud bolts.

FIG. 10shows a front view of a movable crosscutting tool according to a preferred embodiment of the invention. The crosscutting tool40consists of an inner annular body42, through which there is a through-hole41, which is centrally placed. Outside the inner annular body42there is additionally disposed an annular, concentrically arranged body43. The tool40is symmetrical with regard to a plurality of dividing planes which intersect the centre line for the through-hole41. The body thus consists of a plurality of uniform sectors, in the case shown four uniform quadrants. Each such quadrant comprises a curved surface43A-43D with a radius R corresponding to the distance from the centre axis of the mid-hole to the periphery of the edge. Moreover, each quadrant also contains an edge portion44A with a plane surface. A great advantage with the shape of the crosscutting tool40is that the curved surfaces43A-43D can be made with very high precision using conventional, cost-effective machine-working, for example turning. Since these curved surfaces43A-43D are used for positioning/alignment of the crosscutting tool40in the tool housing20, this means that very high precision with respect to alignment, i.e. the arrangement of the through-hole41along a predetermined axis C through the tool, can easily be obtained. The plane surfaces44A of the crosscutting tool40are used to be able to take the blow from the striking piston11and also, on the opposite side44C, for braking the motion of the crosscutting tool40, toward the damper unit30, after the blow has been executed. As can be seen fromFIG. 10, sharp edges of the tool40are eliminated by virtue of their beveling.

FIG. 11shows a fixed crosscutting tool50viewed in perspective. It can be seen that the fixed crosscutting tool50, according to a preferred embodiment, has exactly the same outer configuration as the movable crosscutting tool40, which is rational from many aspects and, inter alia, reduces the production costs. Thus the fixed crosscutting tool also has four curved surfaces53A-53D and four plane surfaces54A-54D. Moreover, the fixed tool also consists of an inner52and outer53annular body. In the inner hollow body52there is a through-hole51similar to that in the movable body40. Unlike the movable tool body40, the fixed crosscutting tool, however, can be provided on one side with a beveled edge portion55around the opening for the inner hole51. This makes it easier to feed a new wire in through the guide sleeve61and onward through the hole51in the fixed tool, since normally the through-hole612of the guide sleeve is somewhat larger than the hole51in the fixed tool50.

When the tool is in use, the parts are assembled as shown inFIGS. 1 and 2. Moreover, as previously described, the entire module unit10,20,30,40and50is fixed in a crosscutting machine (not shown) by the fitting bolts236-239. With the aid of a specially adapted feed device, a rod-shaped material (not shown) is then fed in through the cavity612in the guide sleeve61and then further in through the hole51in the fixed crosscutting tool50and finally also through the hole41in the movable crosscutting tool40. The crosscutting machine is then ready to be started, which means that the driving portion of the striking unit10causes the piston11to accelerate upward so as finally to hit the stop face44A of the movable tool40with high energy velocity. The movable crosscutting tool40is then accelerated upward away from the striking piston11and strikes with high energy with its inner edge in the parting plane between the movable40and the fixed50tool, whereupon a sufficiently large energy shock is transmitted by the rod-shaped material to produce an adiabatic cutting. Next the crosscutting tool40is damped by the damper unit30, as a result of the upper plane surface44C of the tool bearing against a movable unit (not shown) belonging to the damper30so that the striking motion is retarded, after which the crosscutting tool is returned to the striking position as a result of the tool being pressed constantly downward, by the said movable unit in the damper, toward the striking position. Owing to the guide surfaces26E,26F in the hatch, which interact with the side-orientated plane surfaces44B,44D, the crosscutting tool will be prevented from being able to rotate, whereby the same curved surfaces43A,43B come into contact again with the curved surfaces218of the base element21. To a certain extent, and in certain cases totally, the rotational securement can be achieved by interaction between the upper plane surface44C and the movable pressing appliance (not shown) belonging to the damper30. Since the interacting surfaces between the base element21and the movable crosscutting tool40are configured with the same radius R, an exact positioning/alignment of the movable crosscutting tool will be effected. Any dirt which is loosened with the blow will be able to disappear down through the recess217in the base element21, thereby further ensuring that an exact positioning/alignment can be achieved. The fixed crosscutting tool50is held in place during the blow by the fact that its four end faces53A-53D, possessing the radius R, are exactly fitted in the circular recess219in the base element21. From this viewpoint also, it is advantageous for precision reasons to use radiuses, since even a radius in a solid piece is relatively easy to produce with high precision, compared with other multidimensional shapes. A very good fit can thus be obtained between the fixed crosscutting tool50and the recess219in the base element21, which is advantageous from both a mechanical viewpoint and from a durability viewpoint. As already stated, the axial position of the fixed crosscutting tool can easily be adjusted/altered by altering the position of the pressure screw63and hence of the tensioning sleeve62bearing against the fixed crosscutting tool50.

Once the movable crosscutting tool40is back in place, a new desired length of the rod material can be inserted into the through-hole41in the fixed crosscutting tool40. As a consequence hereof, the cut rod bit will be moved out of the hole41and will slide in the cavity260in the hatch26, along the inclined plane262A, so as then to be suitably collected.

As already described, the entire tool unit10,20,30can be quickly and easily fitted and removed, which is important for the purpose of being able to avoid disruptive operating stoppages. Another advantageous solution from a production viewpoint is that the hatch26can quickly and easily be picked out of the tool housing20. This is done by pulling out each lock appliance244,254, whereby the hatch26drops down under its own weight. The height and the contours of the hatch are then matched in such a way that it can be picked out from the open space existing between it and the striking unit10. After this, the movable crosscutting tool40is exposed, so that the striking tools40,50can be easily picked out in the direction of the wire in the opening created by the removal of the hatch26. The crosscutting tool40,50can thus be quickly and easily inspected/exchanged. One advantage with the symmetrical shape of the crosscutting tools40,50is that they can be rotated after a period of use, so that another striking surface is exposed, and also so that second edge portions interact in the cutting of the rod-shaped material. A construction according to the invention thus offers the opportunity for improved utilisation of the tool40,50.

The invention is not limited by the above-illustrated but can be varied within the scope of the following patent claims. It will thus be realised, for example, that the advantageous embodiment of the base element21can also in certain applications be utilised in connection with the use of conventional, rectangular crosscutting tools. The high thickness T8in the direction of impact gives rise to a very rigid and stable construction, at the same time as allowing compact installation of the damper30. In this context, it is also advantageous that the thickness in the transverse direction Ttis sufficiently large to withstand generated forces, yet can be made smaller than the extent in the direction of impact TH, thereby allowing compact installation of the damper30. It will further be realised that the invention, in certain contexts, can be usable in a combination of a movable, radius-possessing crosscutting tool and a fixed crosscutting tool of conventional cross-sectional configuration. It will additionally be realised that the movable tool40can be configured so that symmetry only exists along one plane, with the result, however, that not the same number of different types of altered positions of the striking tool40can be used. It will likewise be realised that the crosscutting tool40,50can be configured with more than four uniform sectors. In addition, it will be realised that the base element21can also be configured using a plurality of non-homogenous elements, which are suitably mutually connected.