Conveyors: power-driven – Conveyor system for moving a specific load as a separate unit – System includes an oscillating or reciprocating load...
Reexamination Certificate
1999-01-15
2001-06-19
Underwood, Donald W. (Department: 3652)
Conveyors: power-driven
Conveyor system for moving a specific load as a separate unit
System includes an oscillating or reciprocating load...
C414S753100, C072S405090
Reexamination Certificate
active
06247578
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for automatically transporting workpieces in a multi-stage forming machine which serves for the non-cutting forming of metal parts.
BACKGROUND OF THE INVENTION
An apparatus of this type known from EP-B-0 206 186 has a top transverse transporting tube and a bottom transverse transporting tube which are driven in time with the forming machine, are guided, in the forming region of the machine, in stationary bearings so as to be able to move back and forth, and on which there are respectively fitted a top tong casing and a bottom tong casing. In order to form a unit which can be displaced with sliding action, the two transverse transporting tubes are connected by a yoke. Workpieces are seized by means of pairs of interacting tong grippers, one being arranged in the top tong casing, and the other being arranged in the bottom tong casing, and the opening and closing movements of the tongs, formed by the respectively interacting tong grippers, being controlled, via transmission levers, by control shafts, arranged rotatably in the transverse transporting tubes, in the form of camshafts. The operation, necessary in hot-forming machines, of seizing workpieces of very different sizes is easily made possible by tongs of this type.
A disadvantage of this apparatus is that, in order to seize a workpiece, a tong gripper has to be advanced up to the workpiece from beneath, as a result of which there is considerable danger of the tong gripper colliding with falling parts. Moreover, in particular in hot-forming machines, the tong grippers are exposed to pronounced soiling, for example by lubricants and/or scale and/or water. In addition, two camshafts are necessary for controlling the opening and closing movements of the tongs and two transverse transporting tubes are necessary for moving the tongs back and forth, and this means that the movements of the two camshafts and of the two transverse transporting tubes have to be coordinated in each case.
OBJECTS OF THE INVENTION
In view of the disadvantages of the previously known apparatus described above, the object of the invention is to provide an apparatus of the type mentioned in the introduction which automatically transports workpieces in a multi-stage forming machine which manages without a tong gripper which is to be advanced, from beneath, up to a workpiece which is to be seized, the intention being to ensure, in a simple and cost-effective manner, that workpieces of very different diameters or stepped workpieces, such as flanged shafts or similar parts with different diameters, can be seized at freely selectable locations. In addition, the construction of the apparatus is to be as straightforward as possible.
SUMMARY OF THE INVENTION
The essence of the invention resides in the fact that, in an apparatus for automatically transporting workpieces in a multi-stage forming machine which serves for the non-cutting forming of metal parts, a tong casing which is fitted on a transverse transporting tube comprises a tong-casing basic body on which there are arranged one or more exchangeable tong modules each with one set of tongs by means of which a workpiece can be seized laterally from above. Each set of tongs is connected, via a coupling location, to its associated transmission means, which are arranged in the tong-casing basic body, have a tong cam for controlling the opening and closing movements of the tongs and, for their part, are in operative connection with a control shaft which is mounted rotatably in the transverse transporting tube. The operation of transporting, from one forming station to the adjacent forming station, a workpiece seized by tongs with pairs of interacting tong grippers and the operation of moving the tongs back take place by the transverse transporting tube moving back and forth, so that the tube is being driven in time with the forming machine and being guided, in the forming region of the machine, in stationary bearings. The tong displacement and/or the temporal behaviour of the tong movements can be adapted to the workpieces by using tong modules with tongs with suitable leverages and/or by adjusting or exchanging the tong cams.
By using tongs which seize the workpieces laterally from above, it is possible largely to prevent excessive soiling of the two respectively interacting tong grippers. It is also ensured that, for example in the case of workpieces becoming larger as a result of wear of the dies, these workpieces are always seized centrally in the respectively interacting tong grippers. In addition, the apparatus according to the invention is of a straightforward construction since the tongs are arranged on a single tong casing fitted on a transverse transporting tube and the opening and closing movements of the tongs are controlled by a single control shaft.
Although tongs which seize workpieces laterally from above have been used for some time now in cold-forming machines, the known apparatuses and tongs do not allow workpieces of very different and comparatively large diameters to be seized. Such tongs are generally designed only for small tong-displacement differences and thus only for workpieces within a restricted diameter range.
In the apparatus according to the invention, the tong displacement can be adapted optimally to the various workpieces by using tong modules with tongs with suitable leverages and/or by adjusting or exchanging the tong cams for controlling the tongs, with the result that there is no need for, inter alia, any unnecessarily large tong movements to be executed. By selecting tongs with suitable leverages, it is possible for relatively large workpieces to be seized without the tongs of adjacent tong modules getting in the way. On the other hand, it is also possible for workpieces with large flanges to be seized at locations of small diameter, in which case the tongs execute a large displacement on account of the space requirement of the flange.
It is easy to exchange tong modules in the case of the apparatus according to the invention in that each set of tongs is connected via only one coupling location to its associated transmission means, which are arranged in the tong-casing basic body and produce the connection to the control shaft for controlling the opening and closing movements.
Since the transmission means assigned to one set of tongs has a tong cam in each case, the sequence of opening and closing movements for each set of tongs can be adjusted individually. In addition, adjustment is user-friendly since for this purpose, unlike in the apparatuses known hitherto, there is no need for the control shaft to be removed from the transverse transporting tube.
In a preferred variant, the transmission means assigned to one set of tongs comprise a tong drive shaft which is arranged at right angles to the control shaft. The tong drive shaft is in operative connection with the control shaft via a bevel gear mechanism. On the tong drive shaft arranged the tong cam by means of which, via at least one further lever of which one end is in operative connection with the tongs or a tong arm via the coupling location, the opening and closing movements of the tongs are controlled.
This variant has the advantage that the tong drive shaft, which controls the opening and closing movements of a set of tongs by means of a tong cam, rotates in the direction of the opening and closing movements, i.e. that there is no need for any movement deflection. Consequently, the mass following the tong cam can be kept lower than in the case of the apparatuses known hitherto, thus permitting quicker and more precise movement. In addition, the vibrational behaviour is improved. The movement deflection taking place between the control shaft and the tong drive shaft via a bevel gear mechanism does not have any adverse effect on the vibrational behaviour if the rotational speed of the control shaft is constant during normal operation.
In order to make it possible for the empty tongs to be moved back immediately, once the workpieces have been relea
Pergher Christoph
Steinhauser Ulrich
Stöckle Stefan
Hatebur Unformmaschinen AG
Selitto Behr & Kim
Underwood Donald W.
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