US3802687A - Holding rail arrangement - Google Patents

Abstract

A holding rail arrangement for a holding device on a coordinate table of a punching press, comprising holding rails fixed on a transverse carriage of the coordinate table, the holding rail being arranged on a plate carried on the transverse carriage, the plate being pressed by yielding holding means against the transverse carriage.

Description

United States Patent [191 [111 3,802,687 Bredow 1 Apr. 9, 197 4 HOLDING RAIL ARRANGEMENT 3,5911 12 7/1971 DeGeorge et a1 83/409 x 1 Inventor: Walter Bredow, Ziegelmasch 16a, 33??32? $393 532122;::113:3::iiiiiiijiijiiiiiijijiii 23283 322 Alfeld, Germany i A 2 1972 [22] Flled pr Primary Examiner-Harold D. Whitehead [21] Appl. No.2 248,3 5 Assistant Examiner-Harold P. Smith, Jr. Attorney, Agent, or Firm-Holman & Stern [30] Foreign Application Priority Data June 2, l97l Germany 2l27249 [57] ABSTRACT [52] US. Cl 269/56, 83/409, 83/62,

269/285, 269/321 ME A holding rail arrangement for a holding device on a [5 lI-Itoordinate table of a punching press omprising hold- Field of Search 56, rails fixed on a transverse carriage f'the oordi- 321 621, 63, nate table, the holding rail being arranged on a plate 409; 51/240 A, 240 R carried on the transverse carriage, the plate being pressed by yielding holding means against the trans- [56] References Cited verse carriage.

UNITED STATES PATENTS 2,339,926 1/1944 Hays 269/97 X 5 Claims, 5 Drawing Figures iMENTED APR 9 I974 SHED 1 OF 4 $.95 iii ||Itmh|1w W l tL fi UW Jfi'U] fi v n U A UH U a T1 w? Q Rm HOLDING RAIL ARRANGEMENT BACKGROUND OF THE INVENTION The invention relates to a holding rail arrangement, and more particularly to such an arrangement on which the holding devices of a coordinate table are attached. Previouslyproposed holding rails of this type are normally attached by screw means to the transverse carriage of the coordinate table and pinned in position. This type of attachment has the disadvantage that more particularly in the case of numerically controlled coordinate tables any collision between the transverse carriage or the holding device attached to it with a turret punching press cooperating with the coordinate table leads to unavoidable damage to the coordinate table. On the other hand, it is not possible to avoid completely collisions between the table and the machine, either owing toincorrect programming or owing to die breakage. Holding devices have been previously proposed which are in a position to give way when the holding devices or the workpieces which are held by them, abut against the machine. Such holding devices with a security device, however, offer the disadvantage that they are comparatively complicated and expensive. Furthermore, there is the disadvantage that for each workpiece at least two holding devices are required. In the case of large workpieces generally more than two holding devices must be employed.

One aim of the present invention is to provide a holding rail arrangement which prevents any collision damage while being simple in construction.

' The present invention consists in a holding rail arrangement for a holding device on a coordinate table of a punching press, comprising holding rails fixed on a transverse carriage of the coordinate table, the holding rail being arranged on a plate carried on the transverse carriage, the plate being pressed by yielding holding means against the transverse carriage. With this arrangement it is possible to ensure that the holding rail is so connected with the transverse carriage that for normal operation the holding rail is fixedly coupled with the transverse carriage .in such a manner that it cannot make any movements in relation to the transverse carriage but, if a collision should occur between the holding device or the workpiece and the machine, it can move out of the way or yield so that an electric switch can be simultaneously operated which puts the coordinate table out of operation.

In the case of one embodiment of the invention the yielding holding means comprise a pin fixed in the transverse carriage, a disc with a conicalseat fitting against the conical dished portion of the plate, a helical spring carried on this disc, a pressing disc transmitting the pressing force of the spring and at least one setting nut, which are screwed on the upper end of the pin. It has been found that such an arrangement operates without any trouble at all.

In order to keep the mass of the moving parts of a coordinate table as small as possible, the transverse carriage is frequently made of light metal, while on the other hand the holding rail must in every case be made of steel. Owing to the different coefficients of thermal expansion of these two materials difficulties frequently arise when the holding rail is fixed by means of screws and pinned to the coordinate table. The present invention makes it possible to avoid such difficulties.

In order to makepossible relative longitudinal movements between the plate mentioned which is made of steel and the transverse carriage which is made of light metal,'the resilientholding means are arranged on the continuous rails with an oblique: seating surface. In ordertobring about a further improvement the attachment points of theholding rail on the transverse car- 'riage are constructed differently. One point is, for example, arranged as afixed :point, while the second is so constructed that it allows for different longitudinal expansion of the holding rail.

In the case of a long length of the holding railor of the associated transverse carriage three holding points are provided for. In this case the fixed point can be in the middle and a holding point can be arranged to the left and to the right of it respectively, the latter holding points allowing for expansion in the longitudinal direction. t

The accompanying drawing shows an embodiment of the invention by way of example.

FIG. 1 shows a plan view of a holding rail with two attachment points.

FIG. 2 is a view of the holding rail with partial sections in accordance with the line of section A-B of FIG.

FIG. 3 shows a section through the fixed holding point in accordance with the line of section C-D of FIG. 1.

FIG. 4 is a section through the fixing point allowing movement in accordance with the section E-F of FIG.

FIG. 5 shows a section through the holding rail with the arrangement of an electric switch in accordance with the section G-H of FIG. 1.

In the case of the embodiment of the invention shown in FIGS. 1, 2 and 3 a holding rail is shown with twoplates 71 and 72 fixed on it. FIG. 3 shows a section through a fixing point. In theplate 71 a conical dished portion orrecess 73 is provided. The connection with thetransverse carriage 81 is brought about via thepin 75,nuts 82, thedisc 76, and the conical disc 74 with an interposedhelical spring 78. In order to keep as small as possible the friction between the conical disc 74 and the pin 75 aconical bush 77 is provided. The attachment of thebolt 75 with thetransverse carriage 81 is ensured by means of thedisc 79 and screws 80. If theholding rail 70 is so strongly loaded by a blow or by a tension force that the force perpendicular to thebolt 75 is greater than the pressing force of thespring 78, the conical disc 74 slides out of theconical recess 73 and theholding rail 70, including theplate 71 attached to it, can recede before the excesive loading. In FIG. 1 thelightening slots 92 which are milled out to reduce the weight of the holding rail are also shown. FIG. 3 additionally shows theselightening slots 92 in section and the recess 91, in which an attachment screw 93 is arranged.

In FIG. 4 of the embodiment shown one attachment or fixation point is shown, which allows a longitudinal movement of the holding rail in relation to thetransverse carriage 81, for example owing to changes in temperature. In theplate 72 there is no conical dished recess as in FIG. 3 but tworails 83, whose adjacent edges 83' are made oblique so as to make an angle of 45 to each other with the result that a :relative longitudinal movement between theholding rail 70 which is made of steel, and thetransverse carriage 81, which is made of light metal, is possible.

FIG. 5 shows the details of the arrangement of theelectric switch 85. When theholding rail 70 has been moved out of the position intended for it, operation of the coordinate table must be stopped at once as otherwise the punching operations would not be carried out by the turret punching press at the correct positions since the workpiece is no longer in the exact required position. In order to be able to switch off the coordinate tableelectric switches 85 are provided at each holding or gripping point. The plungers 85' of the electric switches are arranged to be acted upon by pressing screw 86. At that instant in which displacement of theholding rail 70 occurs, the pressing screw 86 releases therespective plunger 85 of theelectric switch 85 so that theswitch 85 responds and thus the switching off of the drive of the coordinate table can be started. Theelectric switch 85 is attached to theswitch holder 87. Theswitch holder 87 is attached to thetransverse carriage 81 by means of thescrew 88.Reference numeral 89 denotes a conical pin and reference numeral 90 screws, with which theelectric switch 85 is fixed on theswitch holder 87. In the top left-hand part of the drawing thelightening slots 92 are indicated. In the recess 91 the attachment screw 93 is again accommodated.

The invention relates to holding devices on coordinate tables for punching presses, more particularly turret punching presses, in which the holding rails are fixed to the transverse carriage of the coordinate tables. The invention is, however, capable of being put into practice in other machine tools on which controlled, more particularly numerically controlled coordinate tables are provided, in the case of which the same aim may occur as is the case with the present application. The description thus relates to a particular embodiment of the invention as applied to numerically controlled coordinate tables of turret punching presses.

verse carriage at least one attachment point, said' holding rail being arranged on a plate means carried on said transverse carriage, said plate means being urged by yieldable holding means against said transverse carriage at said at least one attachment point and being yieldably responsive to displacements of said holding rail during operation of said press.

2. A holding rail arrangement in accordance with claim 1, in which said plate means has a conical dished portion and said yieldable holding means comprises a pin means fixed at its lower end in said transverse carriage, a first disc with a conical seat disposed around said pin means and fitting against said conical dished portion of said plate means, a helical spring disposed around said pin means carried on said first disc; a second disc disposed around said pin means and carried by said helical spring and at least one setting nut, which is screwed on the upper end of said pin means against said second disc so that said second disc presses against said helical spring and causes said spring to constantly urge said first disc against said plate means.

3. A holding rail arrangement in accordance with claim 1, in which said yieldable holding means is arranged on continuous rails which are fixedly disposed on said plate means, said rails having an oblique seating surface in such a manner that relative longitudinal movement between said plate means and said transverse carriagc is possible.

4. A holding rail arrangement in accordance with claim 3, in which said holding rail is attached to said transverse carriage at at least two attachment points, one attachment point being arranged to act as a fixed point while the remaining points are so arranged that they allow for differential longitudinal expansion between said plate and said transverse carriage.

5. A holding rail arrangement in accordance with claim 2, in which at each said attachment point of said holding rail electrical switches are provided having plungers, each plunger being held in a non-operative position by a pressing screw mounted on said plate means so that on displacement of. said holding rail said pressing screw releases the plunger of each respective switch for stopping a drive means of said coordinate table.

Claims (5)

1. A holding rail arrangement for a holding device on a coordinate table of a punching press, which coordinate table has a transverse carriage, said arrangement comprising a holding rail movably fixed on said transverse carriage at at least one attachment point, said holding rail being arranged on a plate means carried on said transverse carriage, said plate means being urged by yieldable holding means against said transverse carriage at said at least one attachment point and being yieldably responsive to displacements of said holding rail during operation of said press.

2. A holding rail arrangement in accordance with claim 1, in which said plate means has a conical dished portion and said yieldable holding means comprises a pin means fixed at its lower end in said transverse carriage, a first disc with a conical seat disposed around said pin means and fitting against said conical dished portion of said plate means, a helical spring disposed around said pin means carried on said first disc, a second disc disposed around said pin means and carried by said helical spring and at least one setting nut, which is screwed on the upper end of said pin means against said second disc so that said second disc presses against said helical spring and causes said spring to constantly urge said first disc against said plate means.

3. A holding rail arrangement in accordance with claim 1, in which said yieldable holding means is arranged on continuous rails which are fixedly disposed on said plate means, said rails having an oblique seating surface in such a manner that relative longitudinal movement between said plate means and said transverse carriage is possible.

4. A holding rail arrangement in accordance with claim 3, in which said holding rail is attached to said transverse carriage at at least two attachment points, one attachment point being arranged to act as a fixed point while the remaining points are so arranged that they allow for differential longitudinal expansion between said plate and said transverse carriage.

5. A holding rail arrangement in accordance with claim 2, in which at each said attachment point of said holding rail electrical switches are provided having plungers, each plunger being held in a non-operative position by a pressing screw mounted on said plate means so that on displacemenT of said holding rail said pressing screw releases the plunger of each respective switch for stopping a drive means of said coordinate table.

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