EP0073536A2 - Machine for finishing workpiece surfaces - Google Patents

Abstract

The invention relates to a machine for finishing workpiece surfaces, the workpieces attached to spindles being immersed in a moving bed of grinding wheels.

There are automatically working devices T ₁ to T ₃ , which the spindles, to which at least one workpiece to be machined is attached, between a pick-up or drop-off point, such as C, or D ₁ , outside the container 1 and an immersion position in the Move the abrasive bed 2 in the container 1.

The invention is suitable for automating and increasing the work capacity of all vibratory grinding machines in which the workpieces are immersed on spindles in the grinding body bed.

Description

The present invention relates to a machine for finishing workpiece surfaces, the workpieces attached to spindles being immersed in a moving bed of grinding wheels.

Such machines are already known. They consist essentially of a container for receiving the abrasive bed, spindles for interchangeable clamping of the workpieces for the finishing and means for generating a relative movement between the abrasive bed and the workpieces immersed therein.

In the known finishing machines, one or more workpieces are clamped in the spindles. The spindles with the workpieces are then lowered onto the abrasive bed in the container and immersed in it. After finishing the processing, these processes must be repeated in reverse order.

In most of the known machines, the workpieces are still clamped by hand in the spindles and also removed by hand after processing. It is obvious that in this way only a comparatively low machine output can be achieved and that it is associated with high labor costs.

The main purpose of the present invention is to automate a machine of the type mentioned in the introduction, so that the machine output can be increased significantly and the labor costs can be significantly reduced.

According to the invention, a machine for finishing workpiece surfaces is proposed, the workpieces attached to spindles being immersed in a moving bed of grinding wheels, which is characterized in that - automatically operating devices for moving the spindles - in which at least one workpiece to be machined is clamped - Are provided between at least one pick-up and / or delivery point outside the container circumference and an immersion position.

In a preferred embodiment of the machine according to the invention, the container is either circular or in the form of a regular polygon and is equipped with N spindles which are on the radii or the normal to the center Sides of a regular polygon with N corners are arranged. The container is surrounded by a turntable, which has receiving and dispensing places for the spindles and which can be set into a rotation concentric to the container by a motor. On the other hand, the pick-up and drop-off points of the turntable can be served by at least one conveyor system. Finally, means are preferably provided for synchronizing the gradual advancement of the conveyor system, the gradual rotation of the turntable, as well as the functions of the movement devices for the spindles and a stationary auxiliary device for transporting the workpieces between the conveyor system and the turntable, each time the latter two are stopped will.

This preferred embodiment of the machine according to the invention for the finishing of workpiece surfaces is particularly advantageous in that the turntable provides the workpieces to be machined to the individual spindles above their associated machining positions and as the same turntable for workpieces machined in the container by slide grinding, below the associated dispensing positions of the spindles provides. Dispensing and receiving places can coincide thanks to a suitable rotation of the turntable during the processing of the workpieces. It goes without saying that all spindles of the machine can be loaded, then unloaded and reloaded at the same time, after a short period of standstill of the unloaded spindles above the turntable, which allows the latter by a suitable angular rotation, new workpieces to be machined under the spindles for receiving to provide.

On the other hand, since the turntable by means of the conveyor system and the device for transporting the work to be processed Pieces from the conveyor system to the receiving places of the turntable and the finished workpieces can be loaded with workpieces to be machined from the discharge points on the conveyor system to the conveyor system and can be cleared of finished workpieces, and these transports during the processing of the workpieces by immersing them in the bed Grinding bodies takes place, it is understood that this preferred embodiment of the invention makes it possible to avoid practically all dead times during the operation of the surface grinding machine and consequently enables a greatly increased work rate and a completely automatic mode of operation.

An embodiment of the slide grinding machine according to the invention is explained below with reference to the example shown schematically in the figures.

• FIG. 1 shows a diagram of the functioning of this embodiment of the invention.
• Figures 2 and 3 illustrate an elevation and a top view of the embodiment according to the invention.
• FIG. 4 schematically shows the function of the embodiment in elevation.

In FIG. 1, 1 denotes the container of a machine for the finishing of workpiece surfaces, the workpieces attached to spindles being immersed in a moving bed of grinding wheels. This embodiment is a round container which can be rotated about a vertical axis, which is open at the top and which contains a bed of grinding wheels 2.

In general, they are particles of a material that is harder than the workpieces to be machined. The shape and size of the grinding wheels themselves are matched to the corresponding properties of the workpieces to be machined.

With 3 a turntable is designated, which is arranged concentrically rotatable to the container 1. A motor (not shown) and a gear shown schematically in FIG. 1 by a drive belt 4 allow the turntable 3 to rotate concentrically with the container 1. 5 designates a conveyor system, for example a straight conveyor belt that extends approximately tangentially to the turntable 3. On the turntable 3, three receiving places C ₁ to C ₃ and three delivery places D ₁ to D _{3 are} provided alternately, in such a way that in the direction of rotation of the turntable 3, which is indicated by the arrow f ₁ , each place (for example D ₁ ) Equally distant from the places that follow (C ₁ ) and those that go ahead (C ₃ ).

According to the present invention, automatic devices are provided which are denoted by T ₁ , T ₂ and T ₃ in FIG. 1 and which are represented schematically by two downward-pointing arrows and a cross-connection between the upper ends of the arrows. They are used to move the three spindles (not shown) to which at least one workpiece to be machined (also not shown) is attached. Between at least one receiving location of the spindle, such as C ₁ or a delivery location, such as D _1, and an immersion position of the workpiece attached to the spindle in the abrasive bed 2. The symbols T ₁ , T ₂ and T ₃ schematically show that of each one Spindle-fastened workpiece traveled there and back, before and after its processing by means of vibratory grinding. Furthermore, by means of two downward-pointing arrows, which are connected to one another by a semicircle and are denoted by T ₀ , a stationary device is shown, by means of which the workpieces are conveyed between the conveyor location 5 and the turntable 3, in particular its pick-up and drop-off locations C ₁ and D ₁ .

To explain the mode of operation of the slide grinding machine shown schematically in FIG. 1, the raw workpieces to be machined are represented by hatched triangular surfaces and the finished workpieces are represented by hatched circular surfaces. The conveyor belt 5, which moves a workpiece to be machined in accordance with arrow f ₂ , is stopped by a control known per se, the description of which is superfluous, as soon as one of the workpieces to be machined has arrived at the transfer device T ₀ . At the same time, the control mentioned above stops the rotation of the turntable in such a way that a receiving space (for example C ₁ ) is located at the level of the transfer device T _o . The situation described corresponds in particular to the position of elements 3 and 5, which precedes that shown in FIG. 1. The workpiece to be machined is then brought from the conveyor belt 5 to the now free receiving space C _{1 of} the turntable by means of the transfer device T. The control mentioned above then causes the turntable 3 to rotate through an angle of 60 ° in the direction of the arrow f ₁ , such that the receiving location C _{1 of} the turntable 3, which now carries a workpiece to be machined, causes the device T ₁ to move the Facing spindle. The device T ₁ then moves the workpiece to be machined from the receiving location C ₁ into the container 1, where the workpiece is completely immersed in the abrasive bed 2. As a result of the relative movement between the grinding wheels and the workpiece immersed there, the finishing of the workpiece immediately begins in a manner known per se.

The controller continues to cause the turntable 3 and the conveyor belt 5 to be moved step by step, so that at the end of each step a work to be processed piece and one of the receiving places C ₁ to C ₃ face each other at the transfer device T, which carries out the loading of the places, with a picked-up workpiece remaining in the place where it was previously picked up during the following steps. At the end of the fifth step, that is, when the task location D _{2 ',} which is now empty, is opposite the device T ₁ , the latter automatically lifts out the workpiece that was previously immersed in the abrasive body bed and whose surface grinding processing has ended, and then places it to the delivery point D ₂ . Then the turntable 3 is rotated again by five steps until the delivery location D ₂ with the finished workpiece is again at the level of the transfer device T ₀ , which places the workpiece in the compartment of the conveyor belt 5, which is empty and opposite the transfer device stopped.

FIG. 1, on the other hand, shows the situation at the moment already mentioned, in which a finished workpiece is transferred from the delivery location D ₁ into the free compartment of the conveyor system by means of the transfer device T ₀ . The situation shown in Figure 1 otherwise corresponds to an operating state of the machine, which is sufficiently long after the start of operation, so that at this moment all subjects of the conveyor system 5, which are in the direction of conveyance (arrow f ₂ ) in front of the empty compartment - in the The content of the delivery point D _{1 is} to be handed over - is occupied with workpieces to be machined, while all the compartments which are behind the empty compartment are occupied with finished workpieces. At the same time, all of the receiving locations C ₁ , C ₂ and C _{3 are occupied} with workpieces to be machined and can be transferred to the container 1 during the temporary standstill of the machine, where they are subjected to the finishing grinding. The delivery points D ₂ and D ₃ are occupied with workpieces that have already been finished and are gradually transferred to the conveyor system 5 by means of the transfer device T. if it is opposite the transfer device during the further rotation of the turntable 3.

The described mode of operation presupposes, of course, that the machine according to the invention is equipped with a device which synchronizes the gradual movement of the conveyor system 5 and the gradual rotation of the turntable 3 as well as the devices for moving the spindles T ₁ to T3 and the transfer device T _o . According to the present invention, this synchronization takes place - as already mentioned = as follows: the transfer device T ₀ is caused to move a workpiece to be machined according to the inner arrow of the symbol T ₀ and each time an even or odd synchronized stop of the movable elements 3 and 5 to move a finished workpiece according to the outer arrow of the symbol T _o with each odd or even stop. In the meantime, the devices for moving the spindles T ₁ to T _{3 are} caused to deposit the finished workpieces simultaneously on one of the two N synchronous stops, which follow one another, according to the outer arrow at the symbols T _i to T ₃ , and then at the immediately following stops, simultaneously pick up the workpieces to be machined from the task locations C ₁ to C ₃ , according to the inner arrow at the symbols T ₁ to T ₃ .

In FIGS. 2 to 4, the individual parts of the machine are provided with the same reference numbers as were already used in the description in FIG. 1. It is therefore unnecessary to describe these parts again. While Figures 2 and 3 show in detail a possible embodiment with three devices for moving the spindles T ₁ to T ₃ , it being assumed that they are arranged identically and evenly distributed among each other, above the circle Shaped container 1 with a mutual angular distance of 120 °, the schematic representation of Figure 4 relates only to one of the three devices for moving the spindles, for example on T ₁ .

As can be seen from FIGS. 2 to 4, each movement device T ₁ to T ₃ according to the invention has a first horizontal guide rail 6, which is aligned parallel to a radius r _{1 of} the circular container 1 and along which a first slide 7 can be displaced. This first carriage 7 carries a second vertical guide rail 8, along which a second carriage 9 is displaceable. The spindle 10 extends through this second slide 9 and, in this exemplary embodiment, is rotatably supported in the bearings 11a and 11b. The second carriage also carries a gear motor 12 of known type which is coupled to the upper end of the spindle. In this way, all sides of the workpiece to be machined can be exposed to the flow of grinding wheels one after the other. By means of the actuating cylinder, the second slide together with the spindle 10 and the geared motor can be moved along the vertical guide rail 8 up or down as required, as indicated by the arrow V. Another actuating cylinder allows the arrangement consisting of the first carriage 7 and all parts which it carries (8, 9, 10, 11a, 11b, 12) to be displaced along the first horizontal guide rail 6 in such a way that the spindle 10 both over can be brought to the container 1 as well as outside of its scope. The arrangement is oriented such that the translatory horizontal movement takes place along a radius r _{1 of} the container 1, as indicated by the double arrow H in FIG. In this Figure 4, the movement device is shown in a position in which the workpiece to be machined, which is attached in any way to the lower end of the spindle - for example by Screws, clamps, use of a vise, a chuck or jaws - completely immersed in the abrasive bed 2 contained in the container.

The finish grinding results in the illustrated embodiment by the rotation of the grinding bodies as a result of the rotation of the container 1 about a vertical axis and in that gradually all sides of the workpieces to be machined are exposed to the flow of the abrasive bodies, namely as a result of the rotation F that the geared motor 12 causes on the spindle 10. When the processing is finished, the control mentioned above stops the geared motor 12 and switches on the actuating cylinders, also mentioned above, so that the workpiece attached to the lower end of the spindle carries out a spatial movement, which is shown as a chain line in FIG. 4 and is designated by t . In the first part of this movement, the workpiece is moved by means of the lower end of the spindle from the position P ₁ , where it is immersed in the abrasive bed 2, to a position P ₂ , which is located above the upper edge 1a of the container 1, specifically due to an increasing movement of the second slide 9 along the vertical guide rail 8. Then the workpiece is moved to the position P ₃ , which is located above the turntable 3, namely due to a movement of the first slide 7 along the horizontal guide rail 6 from the right to left in Figure 4. During this movement, the finished workpiece runs over the upper edge 1a of the container 1. Finally, the finished workpiece is brought into the position P ₄ by a downward movement of the second slide 9 along the vertical guide rail 8, ie to a delivery point D ₁ on the turntable 3.

If the turntable 3 stops with a pick-up location, such as C ₁ , opposite a movement device T ₁ , the workpiece to be machined, which is located on the pick-up location, brought from the position P ₄ in the opposite direction along the path t to the position P ₁ and immersed in the abrasive material bed 2, ie over the between position P ₃ and then over the intermediate position P ₂ .

The present invention is not limited to the embodiment just described. It includes all variants. The means for charging and decharging the devices for moving the spindles can be chosen freely. Instead of a single conveyor belt 5, which brings the workpieces to be machined and the finished workpieces away, separate conveyor belts can be provided for these two functions, which work accordingly with the turntable 3 by providing two separate transfer devices, both of which are designated by T. . Numerous known and different embodiments are suitable for this transfer device T ₀ itself, which need not be described in detail here. You can use any known manipulator or stationary robot. Of course, it is also possible to have the transfer work between the turntable 3 and the straight conveyor belt or belts 5 carried out by a worker. The turntable 3 and the conveyor belts that operate it can also be replaced by the same or a double number of conveyor belts per moving device such as T ₁ to T ₃ , the charging and decharging processes being carried out for each moving device by one or two linear conveyor systems have to. Of course, the movement sequences of the various conveyor systems must then be synchronized in order to ensure the charging and decharging of the movement devices such as T ₁ to T ₃ . The number of such movement devices is arbitrary; it can also be N = 2 or N> 3. In any case, the movement devices must be arranged in such a way that they fix the movements of the spindles and of those attached to them Workpieces take place in a plane approximately perpendicular to the side wall of the container or, in the case of a circular container, in a radially oriented plane. If the number N of spindles is greater than 3, the container can nevertheless have a circular outline or one in the form of a regular polygon with N sides. The N spindles as well as the associated movement devices can then be arranged in planes that intersect the radii of the circular or polygonal container or that intersect the perpendiculars on the sides of the polygonal container. The present invention is applicable to containers with any floor plan, for example also with a rectangular floor plan. However, a turntable that surrounds the container can only be provided for a container with a circular or polygonal outline. In this case, N pick-up and N delivery places can be provided alternately on the turntable, in such a way that each place has the same distance from each succeeding and preceding one.

If, under this condition, the circular or polygonal container is surrounded by a turntable 3 and if N or 2N linear conveyor systems are provided in order to serve the N pick-up or delivery places that are not located below the movement devices each time the turntable is stopped the control mentioned above can be set up in such a way that the motor causes the turntable to rotate through an angle of 180 ° / N during the downtime of the dispensing spindles located above the turntable.

In this mode of operation of the machine according to the invention, the turntable is stopped by N workpieces at the same time for the entire duration of the finishing grinding. The same places on the turntable are used for loading Send the moving devices as well as their unloading after finishing the processing. In addition, after unloading, the spindles are held in their upper position (P ₃ in FIG. 4) by the associated movement devices until the turntable 3 has rotated through an angle of 180 ° / N. This rotary movement brings the finished workpieces into a position in relation to the conveyor systems for removal on the one hand and, on the other hand, the workpieces to be machined in a position with respect to the movement devices. These workpieces have already been brought to the appropriate locations on the turntable during the previous machining cycle.

The movement devices T ₁ to T ₃ can also be designed differently than described above. Instead of spindles which are driven in such a way that they impart a slow rotational movement to the workpieces to be machined, such driven spindles can also be used that the workpieces are imparted different relative movements with respect to the grinding wheels. It can be, for example, any directional oscillating movements or also translatory movements.

The means described above, each at the bottom. Workpieces fastened at the end of a spindle 10 can run the path t forwards and backwards, other embodiments known to the person skilled in the art can also have. It is sufficient if the movement devices have means which allow the lower end of the spindle to pass forwards and backwards through a path which connects a point inside the abrasive bed 2 and a point P ₃ outside the circumference of the container 1, the path above of the container edge 1a must run. The drives for executing these path movements can be freely selected. The machine according to the invention can be used for all known vibratory grinding processes in which the workpieces are attached to spindles and are immersed in a moving abrasive bed. This applies to the number of workpieces that are fastened to each spindle, the fastening means for the workpieces and the means for achieving the relative movement between the workpieces fastened to the spindles and the grinding wheels. These relative movements can be generated in particular by rotation and / or vibration of the container wall, by centrifugal forces acting on the grinding bodies, etc. Likewise. The control which is to be provided for the machine according to the invention can consist of known means, such as, for example, electromagnetic, electronic, pneumatic , hydraulic, etc. As far as the means for fastening the workpieces to be machined at the ends of the spindles are concerned, they must be selected so that they can be moved by the control mentioned.

Claims (9)

1. Machine for finishing workpiece surfaces, the workpieces attached to spindles being immersed in a moving bed of grinding wheels, consisting essentially of a container (1) for receiving a grinding wheel bed (2), spindles (10) for interchangeable clamping of workpieces for the finishing and means for producing a relative movement between the abrasive bed and the workpieces immersed therein, characterized in that automatically working means (T ₁ , T ₂ , T ₃ ) for moving the spindles (10) in which at least one workpiece to be machined is clamped is provided between at least one pick-up and / or delivery point outside the container circumference and an immersion position. 2. Machine according to claim 1, characterized in that each of the devices (T ₁ , T ₂ , T ₃ ) for the movement of the spindles (10) has a first, horizontal guide rail (6) which is substantially perpendicular to the outer wall of the Container (1) is aligned and along which a first carriage (7) is displaceable, that the first carriage (7) carries a second, vertical guide rail (8) along which a second carriage (9) is displaceable, which the spindle ( 10) carries that drives such as actuating cylinders are provided, namely one for displacing the first carriage (7) between a charging and a decharging point of the spindle (10) and an immersion position for the workpiece fastened to the spindle (10) in the grinding stone bed (2) and a second drive for moving the second carriage (9) between a level that enables the spindle to be attached to it to move the fastened workpiece over the upper edge (1a) of the container (1) and, if necessary, to the level of the pick-up and drop-off points (C ₁ and D ₁ ) of the spindles (10). 3. Machine according to claim 1 or 2, characterized in that the spindles (10) are rotatably mounted about their vertical axis and that their upper end is coupled to a gear motor (12) which is carried by the carriage (9). 4. Machine according to one of claims 1 to 3, characterized in that the container (1) has a plan in the form of a circle or in the form of a regular polygon with N sides, with N spindles (10) on radii or the perpendicular bisectors the N sides of the regular polygon are arranged, equipped and surrounded by a turntable (3), the receiving and dispensing places (C ₁ to C ₃ , D ₁ to D ₃ ) for the spindles (10) and the motor can be rotated concentrically to the container (1). 5. Machine according to claim 4, characterized in that the receiving and dispensing places (C ₁ to C ₃ and D ₁ to D ₃ ) of the turntable (3) of at least one conveyor (5) are loaded, which is substantially tangential to the turntable (3) runs. 6. Machine according to one of claims 4 or 5, characterized in that N places for receiving (C ₁ to C ₃ ) and N places for delivery (D ₁ to D ₃ ) are arranged alternately on the turntable (3), namely in the way that each place ( _C1 or _D1 ) is _equidistant from each following (D ₂ or C ₁ ) and each preceding one (D ₁ or C ₃ ). 7. Machine according to claim 6, characterized in that the motor rotates the turntable (3) by an angle corresponding to 180 ° / N, while the spindle (10) above the turntable (3) is stopped. 8. Machine according to one of claims 5 to 7, characterized in that it comprises means for the gradual forward movement of the transport system (5), the gradual rotation of the turntable (3) and the functions of the movement devices (T ₁ to T ₃ ) for to synchronize the spindles (10) and an auxiliary device (T), the latter being mounted in a fixed position and serving to transfer the workpieces between the transport system (5) and the turntable (3) each time the two are stopped synchronized. 9. Machine according to claim 1, characterized in that the auxiliary device (T) is operated in such a way that with each even or odd synchronized stop a workpiece to be machined in one direction and with every odd or even stop a finished workpiece moved in the opposite sense, while the movement devices (T ₁ to T ₃ ) for the spindles (10) work in such a way that they place finished machined workpieces simultaneously on the delivery stations (D ₁ to D ₃ ) during a synchronized stop of 2 N in succession, in order to pick up workpieces to be machined simultaneously from the recording stations (C ₁ to C ₃ ) at the immediately following synchronized stop.

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