DE3533084C2 - - Google Patents

Description

The invention relates to a swivel arm punch, with a punching table for supporting a punching knife forming stand, one above a column on the stand, e.g. B. hydraulic, height-adjustable swivel arm and with a device having a limit switch for Switching the lifting movement of the swivel arm in its lower Low point.

Such a swivel arm punch is, for example, from FR-PS 12 61 661 known. There are vertically adjustable in the stand Racks provided several limit switches, which with Stops one movable with the column in the stand Stop bar can interact. The facility for Switching the stroke movement of the swivel arm is therefore very complex and therefore expensive. The same applies to the end scarf adjustment. For this purpose, two of the front of the stand made of rotatable shafts the racks adjusted in height at the same time or against each other will. When changing from large to small punching knives has to be adjusted, for example, on a knob. The measure of Rotation is difficult to estimate in the rush of the work cycle. Even when changing from high to low punching knives must be adjusted while accepting the same disadvantage will.

The object of the present invention is a swivel arm punch of the generic type mechanically easier to design and their operation, especially with regard to the Ease limit switch adjustment.

This object is essentially achieved according to the invention solved that the limit switch is firmly connected to the column and so is arranged immediately above the swivel arm that the Limit switch due to the relative movement of the swivel arm in Function in relation to the column when placed on the punching knife occurs. So that is the limit switch with a mechanical extremely simple construction reliably operated, when the swivel arm has reached the lower position.

The required vertical relative movement of the swivel arm to the column can be achieved, for example, by pivoting arm is mounted on the column with little vertical play and / or that the swivel arm consists of such material and is dimensioned so that when it is placed on the punching knife deflects slightly upwards under the punching pressure and this causes the swivel arm to strike the limit switch, when he has reached the lower reverse position.

An independent function of the invented swivel arm punch is ensured, for example, that the limit switch at Actuation of a control signal for switching the stroke movement of the swivel arm. The control signal becomes this used to stop the lifting movement and switch upwards.

Another inventive feature is that the limit switch a time delay circuit for the control signal is connected downstream. The control impulse can be based on this Way for different sized knives and different sized  Forces are delayed differently. With a big one Knives take longer to punch through the machine of the punched material than with a small knife. For the time delay circuit can use commercially available electronic components be used so that an economical production is possible.

To influence the time delay from outside as desired can, is in a further embodiment of the inventive concept the measure of the time delay of the time delay circuit adjustable by means of one or more switches. Will For example, if several switches are used, each switch can have one certain delay time can be assigned. Are the switches arranged in a row, for example the smallest can be the first and the largest punch knife assigned to the last one and the switches in between, the size in between Stamping knife in the appropriate order.

The switches are preferably arranged on the side of the swivel arm. This means that they lie ergonomically within easy reach the operator's second free hand.

This further simplifies the operation of the switches, if they are designed as buttons.

Further goals, features, advantages and possible applications of the present invention result from the following Description of an embodiment with reference to the drawing.

All described and / or illustrated form Features on their own or in any meaningful combination the subject of the present invention also independently of the summary in the claims or their relationship.

Show it:

Fig. 1 shows schematically in side view a swivel arm punch and the invention

Fig. 2 shows the swivel arm punch according to Fig. 2 schematically in plan view.

The swivel arm punch has a stand 1 which contains a piston-cylinder unit 13 for the lifting movement of a column 2 , a hydraulic drive, motor, pump and control valves intended for this purpose and the like. A pivot arm 3 is attached to the column 2 above the punching table 12, if necessary with slight vertical play, by means of retaining rings 4 . A limit switch 6 is attached to the column 2 by means of a switch carrier 5 . The switch carrier 5 projects over the top of the swivel arm 3 in such a way that the actuating button of the limit switch 6 is located directly above the swivel arm 3 . With the help of the handles 7 , which are attached to the outer upper side of the swivel arm 3 , the swivel arm 3 is brought into the correct position above the punching knife 10 , which works on a punching pad 11 of the punching table 12 with the interposition of the punched material (not shown). The punching process is then initiated by pressing a switch 8 on one of the two handles 7 . As a result, the piston-cylinder unit 13 causes the column 2 with the swivel arm 3 to move downward until it occurs on the punching knife 10 . According to the invention, the swivel arm 3 can move slightly upwards relative to the column 2, namely in that the swivel arm 3 is fastened to the column 2 with little vertical play and / or in that the swivel arm 3 moves under pressure from the punching knife 10 bends slightly upwards. The limit switch 6 is actuated by this relative movement from the swivel arm 3 to the column 2 . The limit switch 6 emits a control signal which stops the downward stroke movement and switches over to an upward stroke movement by the hydraulic fluid of the piston-cylinder unit 13 being diverted accordingly. The switching or control signal can be delayed more or less depending on the size of the punch knife 10 . For this purpose, corresponding signal delay elements are provided in the electrical circuit downstream of the limit switch 6 . In order to set the desired delay time in adaptation to the size of the punching knife 10 , a number of selector switches 9 designed as buttons are provided in the outer region of the swivel arm 3 . The first switch 9 is actuated, for example, in the smallest punching knife 10 , the rearmost switch 9 in the largest punching knife 10 and the middle switch 9 in the case of a punching knife 10 of medium size. The selector switches 9 are within easy reach with respect to the second hand of the operator, who holds the other hand on a handle 7 for pivoting the swivel arm 3 and operating the switch button 8 . Due to the different selector switches 9 and the resulting different time delay of the control signal of the limit switch 6 for reversing the movement of the swivel arm 3, it can thus be taken into account that a larger punching knife 10 requires a longer punching time than a smaller punching knife 10 .

Another useful effect occurs in this invention. In a swivel arm punch according to the prior art, in which switching in the lower low point by a relative movement between column with stop cam and limit switch, the limit switch must be so low that the Deflection of the swivel arm is also taken into account.  

When setting to a small stroke, e.g. B. 8 mm and a deflection of the 3 mm swivel arm remains after the return stroke Punching knife only a free space of 8 mm - 3 mm = 5 mm to to the swivel arm. If the material, e.g. B. leather, wavy, this may not be enough.

In the swivel arm punch according to the invention, however, the electrical circuit downstream of the limit switch 6 can be designed such that the return stroke only counts from the release of the limit switch 6 , that is, only when the deflection of the swivel arm 3 is eliminated and the swivel arm 3 leaves the punch knife 10 . In this way it is ensured that between the back of the punching knife 10 and the swivel arm 3 the set punching stroke is fully available as free space.

Reference symbol list

1 stand
2 pillar
3 swivel arm
4 retaining ring
5 switch carriers
6 limit switches
7 handle
8 power button
9 selector switches
10 punch knives
11 punch pad
12 punching table
13 piston-cylinder unit

Claims (8)

1. Swivel arm punch, with a punching table ( 12 ) for supporting a punch knife ( 10 ) forming stand ( 1 ), one over a column ( 2 ) on the stand ( 1 ) z. B. hydraulically, in its stroke position height-adjustable swivel arm ( 3 ) and with a limit switch ( 6 ) having means for switching the stroke movement of the swivel arm ( 3 ) at its lowest point, characterized in that the limit switch ( 6 ) with the column ( 2 ) is firmly connected and so arranged directly above the swivel arm ( 3 ) that the limit switch ( 6 ) comes into operation due to the relative movement of the swivel arm ( 3 ) in relation to the column ( 2 ) when it is placed on the punching knife ( 10 ). 2. Swivel arm punch according to claim 1, characterized in that the swivel arm ( 3 ) is mounted with little vertical play on the column ( 2 ). 3. swivel arm punch according to claim 1 or 2, characterized in that the swivel arm ( 3 ) consists of such material and is dimensioned such that it bends slightly upwards when placed on the punching knife ( 10 ) under the punching pressure. 4. Swivel arm punch according to one of claims 1 to 3, characterized in that the limit switch ( 6 ) emits a control signal for switching the stroke movement of the swivel arm ( 3 ) when actuated. 5. swivel arm punch according to claim 4, characterized in that the limit switch ( 6 ) is followed by a time delay circuit for the control signal. 6. swivel arm punch according to claim 5, characterized in that the amount of time delay of the time delay circuit is adjustable by means of one or more switches ( 9 ). 7. swivel arm punch according to claim 6, characterized in that the switches ( 9 ) are arranged on the swivel arm ( 3 ). 8. swivel arm punch according to claim 6 or 7, characterized in that the switches ( 9 ) are designed as buttons.