Patent Grant
8235645
The present invention relates to a carriage assembly having a housing, having a cam disc and having a carriage which is guided in a linearly movable fashion, with the cam disc and carriage being operatively connected to one another, and with the cam disc being arranged orthogonally with respect to a fastening plane of the housing.
The present invention also relates to a workpiece transport device which uses a carriage assembly of said type and to the arrangement of a plurality of carriage assembly combinations to form a special machine.
Carriage assembles are used, as drives and controllers for tools or tool carriers, for handling devices or for transport devices, in special machines for punching, bending and assembling sheet metal parts or plastic parts. Said carriage assemblies perform more than 100 working strokes per second, often more than 400 per second. Here, the carriage units are fastened with their housing to the special machine, which also supports the drives of the carriage assembles and any drive force transmission arrangements. A driven cam disc is mounted on the housing of the carriage assembly. Here, the cam disc has a working cam disc and, spaced apart axially from the latter, a return cam disc, with the cam disc being operatively connected, by means of incident take-off rollers for the working and return discs, to a carriage which is guided in a linearly movable fashion. Here, the take-off rollers transmit to the carriage the forces which are transmitted by the cam disc. In turn, the carriage carries a tool, a tool receptacle, a handling device or is connected to a workpiece transport device.
Since said special machines generally have a plurality of workstations arranged in series in the processing direction, for example a plurality of bending stations with preceding punching stations or one or more stations in which a base body is fitted with different components which are brought to the assembly line in sequence, said special machines likewise have a plurality of carriage assembles which are often arranged directly adjacent to one another. In special machines for machining small workpieces, it can be the case, in particular in multi-stage workstations without intervening workpiece transport, that the conventional carriage assembles which are arranged directly adjacent to one another can only apply their tools/handling devices to the workpiece by means of off-setting or the like. This has great disadvantages since, on account of the high number of cycles and the force transmission direction being different from the movement direction of the carriage, absolutely precise adjustment of the carriage assembly with constant re-adjustment is necessary, since, especially in the case of workpieces composed of soft material such as plastic, precise, damage-free machining cannot be ensured.
In order to avoid these space-related problems, it is known to also use pneumatic, hydromechanical or electrical tool and transport device drives instead of mechanical tool and transport device drives for special machines. Although said drives are smaller than the known carriage assembles, they however cannot operate in a satisfactory manner, or require considerable control expenditure, at the high number of cycles mentioned in the introduction and under the required complex demands with regard to the adjustment of the stroke position, the maximum stroke, the setting-down speed, the constancy of the linear movement, the minimization of the dead phase, a dwell at dead centre and the like. In principle, mechanical tool and transport drives and therefore the carriage assembles would be preferable.
DE 295 11 071 and DE 103 27 018 disclose carriage assembles in which the cam discs are arranged parallel to a fastening side of the carriage assembly and parallel to a workpiece processing direction. Said cam discs are accessible from a machine operating side, such that they may be exchanged. Said cam discs are in an overhung arrangement. In said carriage assemblies, the maximum diameter of the cam disc defines the width of the carriage assembly, such that the carriage assemblies may be moved no closer to one another than the diameter of a cam disc. Here, conventional widths are more than 200 mm. To reduce the spatial requirement of a carriage assembly, it is known from DE 44 35 282 to provide two L-shaped supports which, with their long limbs, are fastened back-to-back to one another and, with their short limbs, are fastened, parallel to the workpiece processing direction, to a special machine, with the cam discs being fastened, orthogonally with respect to said workpiece machining direction, in each case to the long limb of the L-shaped carrier. The drive of the cam discs takes place by means of gearwheels through the long limb from the rear side of the special machine. As a result of said arrangement, the selected width is reduced to approximately 200 mm for two carriage assemblies, with the exchange of cam discs again taking place from a machine operating side, but under more difficult conditions than in the carriage assemblies mentioned in the introduction. Disadvantages of this prior art are however firstly that the cam discs are still in an overhung arrangement, which results from the selected fastening situation, and secondly the unfavourable guidance of the carriage through an angle of 90°. The latter is guided at its upper end by a frame which is fastened from above to the double-L support, and at its lower end in a groove of a guide plate, with the guide plate being arranged on the special machine parallel to the workpiece processing device.
It is therefore an object of the present invention to specify a carriage assembly which is of small construction and which can be subjected to high loading and which can be used as a tool carrier, a handling device drive or a transport device drive. It is likewise an object of the invention to specify a workpiece transport device which permits high numbers of cycles, and finally to specify a special machine which permits high numbers of cycles while being of small structural size.
The first object is achieved in that the cam disc is designed to be mounted axially at both sides and the carriage is designed to be guided in the interior of the housing. This arrangement of the cam disc advantageously makes it possible to keep the carriage assembly width independent of the cam disc diameter, but simultaneously has the result that the cam disc is mounted in a stable fashion, and thereby drives a carriage in a constant fashion with unchanging parameters, such as for example stroke length and stroke duration, over a long period of time at high numbers of cycles and therefore high rotational speeds. The invention highly advantageously utilizes the free space in front of and behind the carriage assembly. Here, it is not necessary for the cam disc to be arranged centrally in the housing; an eccentric arrangement is by all means conceivable. As a result of the carriage being arranged in the interior of the housing, a closed, functionally reliable design is created, and the carriage is always guided in a reliable fashion even at high numbers of cycles.
In one refinement of the invention, it is provided that the cam disc has a working cam disc and, spaced apart axially from the latter, a return cam disc, and/or that the cam disc is composed of hardened material, is in particular formed in one piece. This advantageous refinement of the invention of the cam disc permits a carriage assembly which operates in a particularly precise manner. The hardened material results in a long service life without significant instances of wear on the running surface of the cam discs. On account of the single-piece design, the cam disc according to the invention can be produced in an extremely precise fashion, and the assembly of individually produced parts with the unavoidable tolerances involved is avoided.
As a result of take-off rollers being arranged between the cam disc and carriage, the force which the cam disc exerts on the carriage is transmitted particularly efficiently without losses. Here, the carriage particularly advantageously has at least one take-off roller bearing arrangement and at least one connecting device, preferably two connecting devices which are situated opposite on both working sides of the carriage. A compact component is highly advantageously provided in this way. The connecting device permits the connection of a tool, a tool retainer, a handling arrangement or other devices which are to be driven. The invention particularly advantageously proposes to provide connecting devices on both working sides of the carriage, with working sides being understood to mean those sides of the carriage which reach the top and bottom dead centres of the linear movement of the carriage. Here, the type of connecting device is coordinated with the application, and can range from simple T-grooves to complex connecting systems.
As a result of the carriage being formed in at least two parts, preferably with a parting surface which is parallel to the fastening plane of the housing, it is highly advantageously possible in combination with a likewise two-part housing, which is formed in the same way, for the cam disc to be exchanged in a simple manner from an operating side of the carriage assembly. While the housing and the carriage remain connected to one another and to the special machine, a simple exchange of the cam disc may take place.
The carriage guides, which are provided in one refinement of the invention, in the interior of the housing, preferably in the form of a plurality of guide plates, permit reliable guidance of the carriage. It is provided according to the invention that said guide plates remain undisturbed in their installed position during a cam disc exchange. Accordingly, said guide plates are arranged such that they remain in that part of the housing which is fixedly connected to the special machine. As guides, consideration is given in particular to maintenance-free plain bearings with graphite lubrication or plain bearings composed of special bronzes. This permits the use of the carriage assemblies according to the invention in clean spaces or in the production of oil-sensitive workpieces. Instead of guide plates, it is also possible to use sleeves if rotationally symmetrical carriages are to be used. As guides for the carriage, consideration is given to linear guides of a wide variety of designs, such as for example roller shoes. Depending on the application, it is also possible to provide central lubrication.
As a result of the carriage assembly according to the invention having a cam disc shaft which supports the cam disc and which is of multi-part design, with a detachable locking device being provided between some of the parts in such a way that the cam disc can be removed from the cam disc shaft, a simple exchange of the cam discs is highly advantageously permitted, such that the carriage assembly according to the invention can be easily adapted to a different application.
If the locking device is formed as a cross-shaped groove with a groove wedge in those parts of the cam disc shaft which can be removed together with the cam disc, and if other parts of the cam disc shaft are formed so as to remain in the device, preferably so as to remain in bearings, it is highly advantageously obtained that the bearing situation of the cam disc shaft remains undisturbed during a cam disc exchange. This lengthens the service life and the precision of the carriage assembly according to the invention. As a result of the locking connection, it is ensured that the shaft, as a uniform component, transmits the drive forces to the cam disc without losses.
The object is also achieved by means of a system composed of a plurality of carriage assemblies, in which individual carriage assemblies are designed such that they can be connected to one another by means of connecting shafts at the ends of the cam disc shafts or by means of direct form-fitting engagement of the cam disc shafts into one another. As a result of the connection of carriage assemblies according to the invention, the advantage of the small structural width on account of the alignment of the cam disc is readily apparent. On account of the small structural width, it is possible for even the smallest of workpieces to be machined without it being necessary for the tools to be guided to the workpiece via off-sets or the like.
The advantages of the invention become particularly clear if the described carriage assembly is used as a controller and/or drive of a handling device, in which said carriage assembly is connected by means of two connecting devices of its carriage to the handling device. Here, handling is to be understood to mean any manipulation of a workpiece which leads to a change in spatial position, that is to say rotations, tilting, linear transport, transfer, etc. As a result of the connection of a carriage at both sides to a handling device of said type, devices are obtained which operate in a particularly precise manner.
The further object of the invention is achieved by means of a handling device, in particular workpiece transport device, having a workpiece transport comb, having a disengagement device which is articulatedly connected to said workpiece transport comb by means of a deflecting limb, and if appropriate having a workpiece fixing unit, with the workpiece transport comb and disengagement device being arranged on in each case one carriage assembly according to the above description. A handling device of said type operates in a precise, constant and permanent manner.
Finally, the invention encompasses a workpiece fixing unit which is embodied as a tilting lever which is designed to be driven by a carriage assembly as described above.
The invention is described by way of example in terms of a preferred embodiment and with reference to the drawing, wherein further advantageous details can be gathered from the figures of the drawing.
Here, functionally identical parts are provided with the same reference numerals.
In detail, in the figures of the drawing:
a shows a detail of the bearing situation. It is possible to see the connection between the shaft adapter 14 and the cam disc shaft 13, with the shaft adapter 14 and the roller-ball bearing 15 remaining installed in the housing 1 when the cam disc 2 is removed. The shaft adapter 14 is connected in a force-fitting manner by means of a cross-shaped groove 16 in that shaft part which is releasable together with the cam disc 2, and a groove wedge 17 which is inserted therein. On the left-hand side of the illustrated device, the bearing cover 26, the roller-bearing housing 15, the shaft 14 and the groove wedge 17 have been graphically removed. Illustrated is the cross-shaped groove 16 in that shaft part which is connected to the cam disc 2, and a spring-loaded ball pin 30 by means of which the shaft adapter 14 is fastened to the cross-shaped groove 16. To remove the cam disc 2, after the removal of the groove wedges 17, the releasable parts of the cam disc shaft 13 are removed from the shaft adapter 14 after the cam disc has been rotated by 90°, with the shaft adapter 14 being open to the front. In this way, the cam discs 2 may be exchanged in a simple manner, such that the carriage assembly according to the invention can be adapted in a simple, fast and uncomplicated manner to different production parameters of the special machine.
b shows the image from
Finally, the invention also encompasses a use of the carriage assembly as a drive of a handling arrangement or as the handling arrangement itself. This is explained on the basis of
a, b show a workpiece clamping device using a carriage assembly according to the invention, and
The carriage assemblies provided according to the invention are preferably coupled to one another such that only a single drive is required. The described device is between 10 mm and 2000 mm long, preferably 512 mm, and can be easily coupled to other identical devices such that it is possible to realize long workpiece transport paths. It is likewise provided according to the invention that two devices may be coupled to one another in such a way as to differ in terms of their operating side, that is to say a workpiece is received in a chamber 57 with its right-hand side and subsequently with its left-hand side. This is advantageous whenever components must be fitted on different sides of a workpiece. A rotation of the workpiece may thus advantageously be avoided.
The described device may be combined with at least one further device in such a way that these are positioned together on the same side along a transport path, and the combs 40 are co-ordinated with one another in a grid in such a way as to provide a seamless handover from one device to the next. It is likewise possible for said devices to be arranged opposite one another in an alternating fashion. It is also possible for two or more devices to be arranged mirror-symmetrically with respect to one another such that, as it is transported, the at least one workpiece is transported in a clamped fashion by means of the opposing chambers 57 of the combs 40. In this way, secured transport, and also a positive handover of the transported workpiece, are made possible, or the workpiece can be held in an assembly station.
Instead of the combs 40, it is also possible to provide further modules, tools or handling devices on the carriage assembly. For example, a roller guide may be fastened to the rail, which roller guide can additionally perform a stroke movement by means of the carriage assembly.
Furthermore, said arrangement which is described in
a,b show an embodiment of a workpiece clamping arrangement 60 which can be used in connection with the above-described workpiece transport device. The illustration shows only two chambers 57 with in each case one workpiece. The workpieces are pressed by the workpiece transport comb 40 against a guide rail 61 which has a first guide edge 62. By being rotated through 180°, the guide rail 61 provides a second guide edge 63 if other shapes of workpieces are to be machined. In the event of the workpiece transport comb 40 being disengaged, the workpiece would be released, which is undesirable in the region of workstations. In order to fix a workpiece, the invention proposes a tilting lever 64 with a clamping end 65 and a tilting end 66 which is arranged on an axle 67 between the two ends. At the clamping end 65, a spring-loaded plunger 68 with a ball head 69 engages into a groove 70 of the tilting lever 64. The spring 71 is supported against a spring ring 72 on the plunger 68 and bears with its free end against a plate 78 through which the plungers 68 extend. The plunger 68 can be driven by means of a disengagement mechanism (not illustrated). Said disengagement mechanism is based on a carriage assembly according to the invention, in which the two working sides of a carriage are connected to a curved surface in the manner of a cam, such that, during the linear movement of the carriage, the cam-like curved surface serves to generate a movement of the plunger 68 perpendicular to said carriage.
The carriage assemblies according to the invention may be embodied as a transfer device 83 which, for example, permits a gripping movement of gripping tongs and a transporting or transfer movement in the x or y direction and in the z direction.
Furthermore, by using the carriage assemblies according to the invention, an assembly line 80 is created which can be formed with a simple drive arrangement on account of the carriage assemblies being arranged above the workpiece transport plane. In each case one drivetrain is sufficient, which drivetrain leads to a group of carriage assemblies to drive a plurality of carriage assemblies.
The invention highly advantageously permits the realization of a special machine of small construction in tabletop size, in which for example a tabletop die with 25 t forming pressure of approximately 20×20×50 cm in size is combined to form a unit with a workpiece transport device according to the invention and one or two workstations, each fitted with carriage assemblies according to the invention. On account of the simple design, a special machine of said type may be realized on a simple frame. This is due primarily to the small structural size of the carriage assemblies, by means of which it is possible to realize even the smallest of strokes, of a few mm, with the highest degree of precision.
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|---|---|---|---|
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| Number | Date | Country |
|---|---|---|
| 295 11 071 | Sep 1995 | DE |
| 44 35 282 | Apr 1996 | DE |
| 103 27 018 | Oct 2004 | DE |
| Number | Date | Country | |
|---|---|---|---|
| 20100013364 A1 | Jan 2010 | US |
