IL44639A - Profile press and precision cutting apparatus - Google Patents

Description

Profile press and precision cutting apparatus The invention relates to a profile press and precision cutting apparatus having a pressure multiplicator converting air pressure into oil pressure, the plunger of which being hydraulically connected with at least one piston, a piston rod connected to said piston acting as a punch and having a cutting tool attached to it, a cutting die, and a base plate.

The vertically movable cutting punch of the known punching machines and cutting presses is guided extremely precisely in direction to the cutting die which is fixed to the machine frame in an axial alignment with the punch.

The cutting gap between the punch and the cutting die depends on the cutting material and the art of cutting. It + amounts to approximately - 150 μ with free cutting tools without guide meanS to approximately i 80 μ with follow dies and to approximately i 30 μ with precision cutting tools.

To secure the same in view of the acting forces and to eliminate deformations and disalignment of the axis, utmost rigid and therefore heavy-weight press bodies are required. In order to keep the narrow tolerances, e.g. guide bolts or columns are provided as well guiding the punch movable with regard to the cutting die fixed on the machine frame. Should the machine frame be made smaller or lighter than usually, in order to save its weight, it v/ould come to elastic deformations of such a machine frame as well as the guide columns by the effect of even small lateral forces. The narrow tolerances of the cutting gap would be surpassed which would inadvertently lead to an instant breakage of the cutting tool and other sequential damages.

FIG. 1 shows the prior art.

A cutting die 1 is fixed on an indicated machine frame 3 by means of clamping bolts 2. The guide columns 4 are fixed on the cutting die 1, the guide columns 4 being axially movable in the bores 5 of a mounting support 6 of a punch 7 so as to guide the punch 7 in the direction of the axis 8 of th© opening.

The same arrangement is to be found also with other embodiments, that means that the cutting die, which is also called a matrice, is firmely connected with the machine frame etc.

It is an object of the invention tp do away with the above-mentioned shortcomings . by providing a profile press and precision cutting apparatus by means of which a precision single cutting or an automatic follow cutting can be carried out with the highest precision by using a common guide means across a separated bearing surface whereby such an apparatus should be light as far as its weight is concerned. With such an apparatus cutting tools serving also the purposes of profile making and other purposes should be applicable.

The invention does away with the technical and economical shortcom n n eas wa cc in a profile press and precision cutting apparatus of the kind referred to, the cutting die is loosely supported by the base plate and is held in parallel with the cutting tool by a guide means fixed to the piston rod which means assures a torsion free guidance of said piston rod.

Advantageously comprises the guide means a mounting support fixed to the piston rod the ends of which are longitudinally shiftable in the grooves of a cutting tool frame and two opposite guide bolts, each of which being connected with its one end with one end portion of the mounting support and longitudinally guided with its other end in a bore of a guide plate lying adjacent to the cutting die, the guide bolts entering as far as the bores of the base plate during the power stroke of the cutting tool whereby the cutting die is spaced from the base plate by which it is partly surrounded by a distance corresponding to the gap between the guide. bolt introduced in the bore of the base plate and the wall of said bore.

The technical novelty of the apparatus consists in the precise centering the cutting die with regard to the punch respectively the cutting tool by means of guide elements, e.g. guide bolts fixed to the body of the movable punch in such a way that the cutting die is loosely and shiftably supported by the base plate which is in opposite to the kind of fixation according to the prior art. Should now come to an otherwise i V.. inadmissible elastic deformation of the cutting tool frame and to the resulting misalignment of the base plate, the displacements remain without influence on the precisely adjusted position of the cutting die.

This is schematically shown in FIG. 2.

The cutting die 9 is loosely supported by the base plate 10 of a machine frame. By an uncontrollable force effect P normal to the axis 11 of the punch it can eventually come to a displacement of the base plate 10 because of the light and space saving structure of the frame aimed at, which displa' cement (it is marked with a' in the figure) has however no influence on the precisely adjusted position of the cutting die 9 because the same is held axially in alignment with the punch by the mounting support 12 fixed on the punch and the guide elements 13 connected to said mounting support which elements are movable longitudinally in the bores 14 of the cutting die 9.

One form out of many application and embodiment possibilities according to the invention is illustrated by the drawings accompanying the application which show PIG-. 3 a longitudinal section of a precision cutting apparatus , FIG-. 4 a section according to line IV-IV of fig. 3, and FIG. 5 a section accordin to line V-V of fi . 3. 44639/2 The apparatus shown in fig. 3 is a precision cutting device which is actuated by a pressure multiplicator having several pistons. Such a device gives the technique of precision tool cutting a new broad range of application, e.g. in building industry. This form displays clearly all the technical novelties and economic advantages of the invention. The shown embodiment is a handy and easily manoeuvrable hole cutting apparatus which can be used e.g. instead of a hand drilling machine and saves upto 80 % of the working time.

The schematically drawn embodiment according to fig. 3 comprises a pressure producing cylinder group 2 , 25 ,26 ,.27, one pressure responsing cylinder 28 and a cutting tool frame 21 which all are connected together in a constructural unit by means of tractor screws 30,31.

Three air operated pistons 3 work on a plunger 34 via a common piston rod. The so generated rydraulic pressure i oil 35 acts upon a working piston 6 to the piston rod 37 of which a cutting tool 38 and a mounting support 39 with the guide bolts 40 are attached.

The guide bolts 40 are attached to the opposite ends of the mounting support "t e 'ends of which. are longitudinally 1 vable in the grooves 22 of the cutting tool frame 29. Each guide bolt 40 is guided in bore 23a of a guide plate 23 being 1cossly supported by a base, plate 20 lying adjacent to the cutting die 41. During the power stroke of the cutting tool' 38 arrive the. guide bolts 40 in the bores 20a of the base plate 20; the diameter of these bores 20a is bigger than that of the guide bolts 40.

The cutting die 41 which is loosely supported by the base plate 20 is spaced from the base plate 20 by a distance a which equals to the gap between the guide bolt 40 inserted in the bore 20a of the base plate 20 and the wall of the bore 20a. The base plate 20 is screwed to the cutting tool frame 29.

By a lateral shock against the cutting tool frame 29 the base plate 20 can be laterally displaced by the distance a with respect to the cutting die 41. This displacement has, however, no effect on the correct position of the cutting die 41 which is held always parallel with the cutting tool 38 because it is connected over the guide plate 23, both the guide bolts 40 and the mounting support 39 with the piston rod 37. Because of this connection no torsional moments will occur which could lead to the torsion of the punch. These torsional moments occur then, when the cutting edge of the cutting tool for. cutting e.g. plastic material is not arranged in a plane, but it forms a spatial curve. The internal longitudinal forces occuring during the cutting process are absorbed and compensated by the base plate 20.

In order to prevent the workpiece 42 (e.g. a steel angle) to be carried along with the returning punch after the ' completed cut action a hydraulically or pneumatically controlled device for holding it down is provided, as it can be seen in fig. 4. The pistons43 of two pneumatic or hydraulic cylinders 44 are connected with a bridge 45 which surrounds the cutting tool 38 and by means of which the workpieee 42 is held on the cutting die 41 during the cutting action and the following return movement of the cutting tool 38.

The necessary conduits and control members for compressed air respectively oil are not shown in fig. 3 because of the clearness. These parts will be covered by a protecting sheath 46 at least within the limits of range of the pneumatic cylinders. The protecting sheath 46 can be designed as a cylindrical body covering all the parts whereby only the stock supply and removal as well as the pressure connections are kept free.

The profile press and precision cutting apparatus is operated preferably by compressed air which is usually available or which can be produced in movable compressor plants or which can be brought in compressed-air bottles to the assembly place. The requirements on the volume of the compressed air are small.

The invention represents an essential technical novelty in building the machine tools and hand tools, because the prime costs and the working costs as well as the production costs of the tool are several times lower than those of voluminous preci sion presses. Accordingly, the range of application of such tools is broader and o ens some new markets for the noncuttin By the combination of the pneumatic-hydraulic pressure multiplicator with the constructional feature of the loosely supported cutting die and in connection with the guide means guiding the cutting tool in parallel with the punch axis and finally also with the so achieved torsionless guidance of the punch, all of which are of the highest importance, a light structure of presses can be achieved. By such a combination cutting and shaping qualities of a high precision and savings of weight ranging up to 90 of the weight of the known apparatusses can be achieved.

Claims (1)

1. CLAIMS press 1 · A pro ile/and precision cutting apparatus having a pressure multiplier for converting air pressure into oil(^ pressure, said multiplier comprising an oil pressure-operated cylinder containing a piston having a piston rod to which is attached a cutting tool acting as a punch, wherein the improvement comprises a base plate, a cutting die assembly which rests on the base plate and is freely movable horizontally in all directions relative to the base late, said base plate having a portion which at least partly surrounds the cutting die assembly, but is radially spaced therefrom in all directions, thereby accommodating, free horizontal movement of the cutting die assembly in all directions relative to the base plate, and a plurality of guide rods which are rigidly connected to said piston rod and are parallel to the direction of travel of said piston rod, said guide rods extending into bores in the cutting die assembly and being long enough so that they extend into said bores throughout the entire stroke of said piston rod, to maintain the cutting die assembly in alignment with said piston rod during the cutting operation, irrespective of misalignment of the cutting die assembly with the base plate, thereby producing torsion-free guidance of the cutting tool and permitting the base plate to take up internally acting forces. 2· A profile press and precision cutting apparatus having a pressure multiplier for converting air pressure into oil pressure, said multiplier comprising an oil pressure-operated cylinder containing a piBton having a piston rod to which is attached a cutting tool acting as a punch, wherein the improvement comprises a base plate, a cutting die assembly supported by the base plate, said base plate having a portion which at least spaced therefrom, and guide means which slidably connects said piston rod and said cutting die assembly a d holds them in alignment, during the cutting operation, irrespective of misalignment of the cutting die assembly with the base plate, thereby producing torsion-free guidance of the cutting tool and permitting the base plate to take up internally acting forces, s id guide means comprising a mountain yoke fixed to the piston rod, a fixed frame having grooves in ¾hich the ends of the yoke are guided during the stroke of the piston rod, and a pair of guide rods, each having one end fixed to one end of the yoke, the cutting, die assembly cpmprising a guide plate having two bores in which the other ends of said rods are longitudinally guided, and the base plate having openings into which said other ends of the rods enter during the power stroke of the piston rod. 3· Apparatus as claimed in Claim 2, characterized in that the openings in the base plate receive the ends of the guide rods with a radial clearance as great as the radial clearance between the cutting die assembly and the surrounding portion of the base plate. For the Applicants BR* PAETHERS HEtmz