Punch Press
The invention relates to a punch press, in which compressive machining is performed on a blank. The punch press includes tools, a ram, a drive element of the ram, and a precise-positioning operating device for moving the drive element of the ram, as well as a precise-positioning moving element for moving the ram in the direction of the tool row to the location of the desired tool. According to the invention the moving element of the ram is arranged to operate using the same moving operating device of the ram.
The present invention relates to a punch press, in which compressive machining is performed on a blank, which punch press is of a type according to the preamble to claim 1,
Very many types of punch presses, for example sheet-material machining centres, are known while patent publication FI 68545 discloses a basic method for determining and moving the positions of a blank and a machining head. U.S. Pat. No. 5,199,293 and U.S. Pat. No. 5,092,151 disclose a mechanism, in which a force is directed to a ram moving a tool, through a control head of the ram using two or more sloping surfaces. When the sloping surfaces move relative to each other, the movement produced by the drive element of the operating device of the ram is directed as desired to the blank being machined. In patent FI 108924 is a ram drive head and control element with a construction as a roller-sloping-surface pair. In the constructions described above, a rotating revolver type of tool holder is generally used, even though a linear tool holder would be more economical in terms of manufacturing costs. Publications U.S. Pat. No. 2,458,160 and DE 3339340 disclose sheet-material machining centres.
The invention is intended to create a punch press that can be manufactured more economically than before, in which a linear tool holder is used. The characteristic features of the punch press according to the present invention are stated in the accompanying claim 1. If the same precise positioning operating device is used to position the ram relative to the tools and to drive the tools by means of the ram, a considerably cheaper implementation of a punch press will be achieved. The term driving the tools by means of the ram refers to creating the necessary compressive movement.
In a punch press, compressive machining directed to a blank is performed. The blank can be, for example, of plate, profiled, or sheet material. The punch press includes a blank-feeding line and exit line, which can be implemented in many different ways. The lines can be based on rollers, which are on a plane, permitting the blanks to move along the feed lines in the punch press. The lines can also be of a robot type, in which case a robot places the blank for machining. The same or another robot removes the machined blank after machining. Such lines are widely known in the art, making it unnecessary to describe them in greater detail in this connection.
The punch press also includes tools. The blanks are machined by means of several different types of tool, by means of which the desired holes and impressions are created in the blanks. The tools comprise a plunger and a stop, by means of the joint action of which the desired machining result is obtained. In the present application, the plunger is used as a synonym for the word punch and stop is used as a synonym for the word die. However the essential feature is the corresponding operation achieved using these. The tools are placed in a tool holder, so that a series of tools is formed. The tools can include tools for very many different types of operation, such as piercing, forming, edging, chasing, or bending. The blanks are fed between the plunger and the stop, where they are machined. The plane, on which the machining takes place, is referred to as the work plane. The machining of the blanks takes place in practice by pressing the plunger part of the tool towards the stop, thus shaping the blank between them.
The plunger is moved using a ram. The ram has at least two operating positions, which are the rest position and the work position. In the rest position, the ram does not touch the plunger. In the work position, the ram is in contact with the plunger. The ram has two ends, the first of which is in contact with the plunger in the work position. The other end of the ram is the drive head, from which force is directed on the ram to perform the machining event of the plunger.
The movement of the ram and indirectly of the plunger is performed using the drive element of the ram. The drive element moves perpendicularly to the direction of movement of the ram. By means of this drive element, the force necessary to operate the ram is directed to the drive head of the ram.
The drive element of the ram is moved by an operating device. The operating device can be, for example, a servo motor. The positioning of the drive element of the ram should be very precise, so that the desired movement is transmitted by the ram to the plunger, so that the plunger will perform the desired movement relative to the blank. For this reason, the positioning should be precise. The drive element of the ram and the drive head of the ram can be implemented in many ways. They can be, for example, bevelled surfaces, which are coated with some substance with a low sliding friction, such as Teflon. The drive element and the drive head can also be a pair formed by a nose roller and a ridged stop. The nose roller can be either the drive element or the drive head, and correspondingly the ridged stop can be either the drive element or the drive head.
The selection of the correct tool from the tools is based on moving the ram to the location of the desired tool. Thus, a moving element that can be precisely positioned is required to move the ram in the direction of the tool row. The moving element is driven by an operating device, which can be, for example, a servomotor. The motion of this too should be precise. The term precise referred to in the two connections above means that positioning should be possible with an accuracy of 0.01-0.5 mm, preferably 0.15-0.2 mm. Operating devices capable of such precise positioning are expensive, so that they form a significant part of the manufacturing costs of the machine.
After the work stage, the ram and the plunger should be returned to the rest position, to allow the blank to be realigned relative to the tool. At the same time, a change may be made to the use of another tool. The return of the ram to the rest position takes place using return means. The return means can be, for example, springs or cylinders.
The plunger of the tool is used to made a linear movement against the stop perpendicular to it. The blank is machined in the work plane between these, which is at right angles to the direction of movement of the ram. In other words, the direction of movement of the plunger is normal to the work plane. In the work plane, the blank is directed to the correct location by the moving means. The moving means are thus used to move the blank relative to the tools, i.e. to move the moving means relative to the blank.
In the solution according to the invention, the moving elements acts surprisingly simultaneously as the operating device moving the drive element of the ram. As stated above, the moving element and the operating device must both operate with precise positioning. Manufacturing costs can be reduced considerably, if the operating device moving the drive element is at the same time also the moving element of the ram. The solution according to the invention requires one component less performing precise positioning than the solutions according to the prior art.
In terms of constructional simplicity and operation, the tool holder is linear and parallel to the movement of the drive element of the ram. In addition, a linear tool holder is cheaper to manufacture. If the tool holder is parallel to the drive element of the ram, a construction is achieved, in which the same operating device can be used as the drive element of the ram and as the moving element of the ram when selecting a tool. In other words, the same operating device, which moves the drive element of the ram, is used as the moving element of the ram. Thus only a single operating device is required to perform the two positionings. The direction, in which the drive element moves, is preferably the same direction as the direction of movement of the body of the operating device.
In one embodiment, the precisely positioning operating device is a rolling screw. The use of a rolling screw in the embodiment in question is justified, despite its high price, by its high precision. In addition, the use of a rolling screw achieves a suitable speed, because high rotation speeds can be used in a rolling screw. In addition, the construction in question has low friction, so that wear and heating are small. In the punch press according to the invention, the rolling screw used is preferably a ball-race screw. A ball-race screw has the advantage over roller screws belonging to the group rolling screws of having a simpler construction. In addition, ball-race screws are cheaper. Because a great load-bearing capacity is not required without increasing the diameter of the screw, the use of a ball-race screw is advantageous.
In a second embodiment, the punch press includes a machine body and an operating-device body. The blank-positioning devices comprise the linear moving means of the operating-device body, and linear feed devices, which are at right angles to each other. The linear movement can be implemented very precisely, for example, with the aid of rail structures. It is therefore advantageous to implement the positioning means with the aid of separate linearly movable structures. If the movement is examined relative to the machine body, it can be seen that the positioning means comprise two parts. The first part is an operating-device body and the second part is transfer means. The transfer means are in connection with the totality formed by the feed line and the exit line. These two totalities move at right angles relative to each other. In addition, both move relative to the machine body in only one direction linearly, in the direction permitted by the rail structure. The tool holder can be attached permanently to the operating-device body, in which case the tools move along with the operating-device body. The blank is, for its part, attached to the transfer means and is moved using the transfer means.
In a third embodiment, the operating element and the drive head of the ram are formed of a rolling element and a sloping surface. The conversion of sliding friction into rolling friction reduces wear in the components. There is no need to use lubricants between the planes, so that the apparatus remains clean. In a preferred embodiment, the operating element of the ram is a rolling element. Such a construction is simpler to construct and more reliable in operation. The rolling element is very advantageously a roller nose, which is previously known in the technology sector in question.
In a fourth embodiment, the moving element of the ram comprises the said operating device and grip means belonging to it. This achieves an embodiment, in which the drive element and the operating device use entirely the same precise-positioning components. In addition to this, the operating element includes grip means. When using entirely the same precision-positioning components an embodiment is achieved, in which the very expensive component is fully exploited for carrying out two functions. The ram has preferably at least three operating positions, which are a rest position, a work position, and a transfer position. Thus the grip means can be all the time below the nose of the operating device, but they touch the ram only when the ram is in the transfer position. No moving grip means are required in connection with the operating device, so that the construction associated with the operating device becomes simple and easily manufactured.
In a fifth embodiment, the grip means include a cylinder in connection with the ram, by means of which the ram is raised to the transfer position. This allows the components permitting movement, which permit the ram's third transfer position, to be implemented using well-tried technology. There are preferably two cylinders on top of each other, in which case the first cylinder is used for returning to the work position and the second cylinder for moving to the ram's transfer position. It is advantageous to use two cylinders on top of each other, as they can be located in the centre of the ram and its vertical support guides. Thus the force of the cylinders directed to the ram is in the desired direction and raises the ram upwards, without causing lateral forces that twist the ram and strain the vertical support guides. Pneumatic or hydraulic cylinders can be used as the return cylinders. It is self-evident that many other types of cylinder and springs, which can be operated, for example, using nitrogen, are suitable as the return means. The cylinders are preferably pneumatic, because great forces are not required in the application. In addition, a pneumatic embodiment is cleaner in use.
In the following, the invention is examined in greater detail with reference to the accompanying drawings, depicting some applications of the invention, in which
In the punch press 10 according to the invention shown in
The ram 30 shown in
In the punch press of
According to
The operation of the return means is described in greater detail in connection with
In
In
In
In other words, the ram is moved downwards by the pressing effect of the roller nose, and is moved upwards by the lifting effect of the cylinders. This is an advantageous construction, as the downwards movement must be more precise to achieve the desired machining effect. In addition, when moving the ram upwards, not much force is required, so that the upwards movement of the ram can be implemented using pneumatic cylinders.
Claims
1. Punch press, in which compressive machining is performed on a blank, which punch press includes:
- a feed line and an exist line for the blanks,
- a tool series, which comprises several tools and a tool holder, in which tools are placed in a row, and in each tool of the tool series there is a plunger and a stop, between which the blank to be machined is arranged to be fed from the feed line,
- a ram, which has a rest position and a work position, which ram has a first end and a second end, which first end of the ram is arranged in contact with the plunger is the work position, and which second end of the ram is arranged to be the drive head of the ram to move the plunger in order to perform the machining event,
- a drive element of the ram, which is arranged to move in a direction perpendicular to the direction of movement of the ram, by means of which the drive element is arranged to direct force onto the drive head of the ram, in order to drive the ram,
- a precise-positioning operating device for moving the drive element of the ram,
- a precise-positioning moving element for moving the ram in the direction of the tool row to the location of the desired toll,
- return means for returning the ram to the rest position,
- positioning means for aligning the selected tool and the blank to be machined relative to each other in the work plane, which is at right angles to the direction of movement of the ram, characterized in that the said moving element of the ram is arranged to operate using the same said moving operating device of the ram.
2. Punch press according to claim 1, characterized in that the precisely positionable operating device is a rolling screw.
3. Punch press according to claim 1, characterized in that the rolling screw is a ball-race screw.
4. Punch press according to claim 1, characterized in that the punch press includes a machine body and an operating-device body, and the positioning devices comprise linear operating-device body moving devices and linear feed devices, which are at right angles to each other.
5. Punch press according to any of claim 1, characterized in that the drive element and the drive head of the ram are arranged to be formed of a roller and a sloping surface.
6. Punch press according to claim 1, characterized in that the drive element of the ram is a rolling element.
7. Punch press according to claim 6, characterized in that the rolling element is a roller nose.
8. Punch press according to claim 1, characterized in that the said moving element of the ram comprises the said operating device and of the grip means belonging in connection with it.
9. Punch press according to claim 1, characterized in that the ram has at least three operating positions, which are a rest position, a work position, and a transfer position.
10. Punch press according to claim 9, characterized in that the grip elements include a cylinder in connection with the ram, by means of which the ram is raised to the transfer position.
Type: Application
Filed: Apr 23, 2007
Publication Date: Jul 30, 2009
Applicant: AKSELI LAHTINEN OY (Mikkeli)
Inventor: Rauno Lahtinen (Hietanen)
Application Number: 12/226,167
International Classification: B21D 28/20 (20060101); B21D 28/04 (20060101); B21D 28/26 (20060101);