GB1565587A

GB1565587A - Machine for the coiling of helical springs

Info

Publication number: GB1565587A
Application number: GB4064977A
Authority: GB
Original assignee: Spuehl AG
Current assignee: Spuehl AG
Priority date: 1976-10-01
Filing date: 1977-09-30
Publication date: 1980-04-23
Also published as: AU510327B2; DE2644352A1; FR2366074A1; AU2881577A; FR2366074B1

Description

(54) MACHINE FOR THE COILING OF HELICAL SPRINGS (71) We, SPUHL AG, a Swiss body corporate, of 18 Lukasstrasse, 9009 St.

Gallen, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a machine for the coiling from spring wire of helical, coiled springs having mutually abutting coils, and for the formation of loops at both ends of the coiled springs, the machine being of the kind in which the spring wire is periodically pushed by means of feed rollers and a guide against coiling fingers and the coiled spring blank is cut off by means of a cut-off knife from the spring wire.

Machines of the kind are known by means of which helical springs of different diameters and having different leads can be manufactured, and by means of which loops of different shapes may also be formed automatically on the ends of the spring blanks. In these known machines, particularly the devices which take over the coiled spring blanks and feed them to the loop forming appliances, as also the loop forming appliances themselves, are very complicated, as they need to be adjustable to meet a variety of requirements. Consequently, such machines are also very expensive.

There is a great need, however, for helical springs having diameters of between approximately 15 and 20 mm, and having simple circular loops at both ends, which loops may extend either parallel with or perpendicularly to each other, with the coils of the spring being in mutual abutment.

It is an object of the invention to provide a coiling machine of the type initially mentioned, suitable only for the manufacture of predetermined types of helical springs, but very simple in construction and therefore very economical in cost.

The machine in accordance with the present invention comprises a two-armed transfer lever for the spring blanks, which is arranged on a shaft driven by the driving motor of the machine, the lever arms, extending at an angle of 1800 with respect to each other, being provided with surfaces in the form of cutting knives to permit either lever arm to engage between the coils of a respective spring blank to hold the blank on the lever arm, before the blank is cut off, and which, after the cutting-off of the spring blank, is together with the spring blank engaged thereon, rotated by means of its shaft through 1800 to a position in which the loops are produced simultaneously at both ends of the spring blank, supported on the respective transfer lever arm, by means of loop forming appliances.

This construction enables both loops to be produced simultaneously in the same operating position. This is constructionally simple, and also has the advantage that the forces applied to the springs by the loop forming appliances virtually cancel each other out.

A further advantageous feature of the machine according to the present invention is that the shaft supporting the two-armed lever for the spring blanks may be driven by the driving motor of the machine via a friction clutch, and may be provided with a flange having two abutments, disposed at an angle of 1800 with respect to each other, and that a push rod, operatively connected to a cylinder-piston unit, which also actuates the cut-off knife, may be arranged to cooperate with the abutments, so that the insertion of a lever arm of the two-armed transfer lever between two coils of the spring blank is realised by a stroke of the push rod against one of the abutments on the flange.In consequence, the torque transmitted by the friction clutch can be very small, since it has to serve only to rotate the shaft, together with the transfer lever, and to strip the finished spring from the latter. The more substantial forces required to insert the lever arm between two coils of the spring blank can be applied by the cylinder-piston unit, which must, in any case, be of strong construction for operating the cut-off knife.

An embodiment of the invention is further described hereinafter with reference to the accompanying drawings, in which: Fig. 1 is a diagrammatic side elevation of the machine according to the embodiment showing the drive mechanism arranged on the rear side thereof; Fig. 2 is a front elevation of the machine shown in Fig. 1; Fig. 3 is a larger-scale elevation of the spring coiling mechanism of the machine Fig. 4 is a partial view of the coiling mechanism of Figure 3, together with a finish-wound spring; Fig. 5 is a partial view of the machine, showing a two-armed transfer lever used for transferring the spring blanks; Fig. 6 is a longitudinal sectional view of the driving shaft for the two-armed transfer lever shown in Figure 5;; Fig. 7 is a view of a spring blank in a loop forming appliances of the machine of the embodiment, and Fig. 8 shows a helical spring produced by means of the machine of the embodiment.

Referring to the drawings, the machine of the embodiment serves for the coiling of helical springs and for the formation of loops at the ends of the springs. Such a helical spring is shown in Fig. 8. The machine comprises a frame 1, on the front side of which the spring coiling mechanism 2 and the loop forming appliances 3a and 3b are arranged. The drive 4 for the coiling mechanism 2 and a transfer device 5 for transferring spring blanks 12 from the coiling mechanism 2 to the loop forming appliances 3a, 3b, is situated on the rear side of the machine frame 1.

The coiling mechanism 2, indicated in Figures 1 and 2 and shown in larger-scale view in Fig. 3, is of known construction.

Accordingly, the mechanism is described hereinafter only in so far as this is essential to an understanding of the invention. The two loop forming appliances 3a, 3b, are also of known construction, and are not, therefore, described in further detail.

The wire 6, which is to be wound, is fed between guiding rollers 7 and a pair of feed rollers 8a, 8b, to a guiding member 9, at whose exit point 9a the wire is pushed against two coiling fingers 10, 11. The wire is engaged by these coiling fingers and bent over in such a way that a spring blank 12, having abutting spring coils, is reproduced.

The lower feed roller 8b is journalled in the machine frame 1 and is driven. The upper feed roller 8a is biassed against the lower roller 8b by a spring 13, whose initial compression is adjustable by means of a spindle 14. The two coiling fingers 10, 11 are attached in a conventional manner to adjustable slides 15, 16, which are guided in holders 17, 18.

As shown diagrammatically in Figs. 1 and 2, the drive to the feed roller 8b is by means of a motor 19 via a first chain 20 to a sprocket wheel 21, which is connected via a known claw coupling 22 to the shaft 23 of the feed roller 8b. So-called highspeed feeding of the wire 6, which is to be coiled, is realised by means of this drive.

On disengagement of the claw coupling 22, the shaft 23 is driven via a transmission mechanism (not shown) having an electromagnetic clutch. In this case, the wire 6 is advanced only very slowly. This so-called creep feed is switched on just before each spring blank 12 attains its predetermined length. In order to ensure that the length of wire in the spring blank 12 is always exactly the same, its length is scanned by means of a commercially available inductive proximity sensor 29 (Fig. 4). The latter disengages the above-mentioned electromagnetic clutch when the desired length of the wire is reached. The proximity sensor 29 is mounted in a holder 24, which is pivotable and locatable, in a support 25, axially with and transversely to the spring blank 12 and about its axis. In this way, it is possible to produce spring blanks 12 of identical length.

The coiling mechanism also includes a cut-off knife 26, which is mounted in a guide 27. It is actuated by means of a pneumatic cylinder-piston unit 28 via a piston rod and a pivoted lever 30, which is pivotable about an axle 31. The lever arm 30a actuates the cut-off knife 26, while an adjacent lever arm 30b actuates a push rod 32, whose function is described hereinafter.

A sprocket wheel 33 (Figures 1 and 2), which drives a sprocket wheel 35 via a chain 34, is also mounted on the shaft 23.

The sprocket wheel 35 drives a transmission mechanism 36, a further sprocket wheel 37, and, via a chain 38, a sprocket wheel 39, mounted on a shaft 40 pertaining to the above-mentioned transfer device 5, shown in Fig. 6. The shaft 40 is journalled rotatably in the machine frame 1. At its end adjacent to the coiling mechanism 2, the shaft 40 is provided with a boss 41, having a two-armed transfer lever 42, whose lever arms 42a, 42b, extending at an angle of 1800 with respect to each other, are provided with knife-like surfaces at their ends. The sprocket wheel 39 is a component of a known friction clutch 43, which is mounted on the opposite end of the shaft 40 to the transfer lever 42. The friction clutch comprises a component 44, rigidly connected to the shaft 40, and a spring-loaded pressure plate 45, and also friction linings provided on both sides of the sprocket wheel 39. In a known manner, the sprocket wheel can drive the shaft 40 only so long as no substantial braking force is applied to the latter. Behind the friction clutch 43 is a flange 47, which is rigidly attached to the shaft 40, and which, as shown in Fig. 5, is provided with two radial abutments 47a, disposed at an angle of 1800 with respect to each other.

The above-mentioned push rod 32, which is connected to the lever arm 30b, lies in the plane of the flange 47, and, in its normal position, is in abutment with the periphery of the flange.

Fig. 5 shows the method of operation of the transfer device 5 shown in Fig. 6. The sprocket wheel 39 drives the shaft 40, together with the boss 41 and the transfer lever 42, in the direction of the arrow 48, until one of the abutments 47a is in abutment with the end face of the push rod 32.

In this position, the middle region of the push rod 32 is also still in contact with a stop 49. This position of the push rod 32 is shown by a heavy broken line in Fig. 5.

The transfer lever 42 now remains inoperative until a spring blank 12 is finish-wound, which state is determined by means of the proximity sensor 29. Compressed air is now applied to the cylinder-piston unit 28, whereby the pivoted lever 30 is actuated.

Via the lever arm 30b, the pivoted lever 30 moves the push rod 32 in a roughly axial direction, whereby the flange 47 is moved in the direction of the arrow 50. Consequently, one of the knife-like end portions of the transfer lever 42 is engaged between two coils of the spring blank 12, whereby the spring blank 12 is held on the transfer lever 42. Immediately following this, the blank is parted from the wire 6 by means of the lever arm 30a and the cut-off knife 26, and thereby released.

Since the push rod 32 is also in abutment with the stop 49, it is not only displaced axially, but also pivoted to some extent, so that before the end of its stroke, it slides out of the abutment 47a and releases the flange 47. The continuously driven sprocket wheel 39 can now once more drive the transfer arm 42, via the friction clutch 43, in the direction of the arrow 48, until, after rotating through 1800, the arm 42 is again stopped, owing to the push rod 32, which has meanwhile returned to its initial position, striking against the abutment 47a. Meanwhile, a further spring blank 12 has been wound, and the described process recommences.

The spring blank 12, held on the end of the transfer lever 42, is moved through 1800 by rotation of the transfer lever. It comes into the region of two loop forming appliances 3a and 3b (Figs. 2, 5 and 7), in the position in which the other end of the transfer lever is inserted into the as yet unparted spring blank 12.

The construction of the loop forming appliances is known, and is described, for example, in German Patent Application 1,883,011. They comprise an anvil and a driven ram for forming the hooklike loops on the ends of the spring blank 12. Since the loop forming appliances are not pertinent to the invention, they are not further described. An essential feature is, however, that they both engage the two ends of the spring blank and form the loops simultaneously. Thus, the forces applied to the spring blank balance each other out. On completion of the formation of the loops, the transfer lever 42, driven by means of the friction clutch, is detached from the finished spring. The spring is then released and delivered into a collecting bin.The loop forming appliances are pivotable with respect to the machine frame 1, so that it is possible to arrange the two loops at the ends of the spring in one plane. or in two planes perpendicular to each other.

WHAT WE CLAIM IS:- 1. A machine for the coiling of helical springs having mutually abutting coils, and for the formation of loops at both ends of the springs, of the kind in which the spring wire which is to be coiled is periodically pushed by means of feed rollers and a guide against coiling fingers, which coil it in the form of a helix, the spring blank being cutoff from the wire by means of a cut-off knife, wherein a two-armed transfer lever for the spring blanks is arranged on a shaft driven by means of the driving motor of the machine, the lever arms of the transfer lever extending at an angle of 180C with respect to each other, and being provided with knife-like surfaces, to permit either lever arm to engage between two coils of a respective spring blank to hold the bland on the lever arm, before the cutting-off of the blank, and wherein, following the cutting-off of the spring blank, the transfer lever together with the spring blank engaged thereon is rotated through 1800 by means of its shaft to a position in which the loops can be produced simultaneously, by means of loop forming appliances at both ends of the spring blank supported on the respective transfer lever arm.

2. A machine according to claim 1, wherein the shaft, to which the two-armed transfer lever for the spring blanks is fitted, is driven by the driving motor of the machine via a friction clutch, and is provided with a flange having two abutments disposed at an angle of 180C with respect to each other, and there is provided a push rod, operatively connected to a cylinderpiston unit which also actuates the cut-off knife, cooperating with the abutments, so that the insertion of a respective lever arm of the two-armed transfer lever between two coils of the spring blank is effected by a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. rigidly attached to the shaft 40, and which, as shown in Fig. 5, is provided with two radial abutments 47a, disposed at an angle of 1800 with respect to each other. The above-mentioned push rod 32, which is connected to the lever arm 30b, lies in the plane of the flange 47, and, in its normal position, is in abutment with the periphery of the flange. Fig. 5 shows the method of operation of the transfer device 5 shown in Fig. 6. The sprocket wheel 39 drives the shaft 40, together with the boss 41 and the transfer lever 42, in the direction of the arrow 48, until one of the abutments 47a is in abutment with the end face of the push rod 32. In this position, the middle region of the push rod 32 is also still in contact with a stop 49. This position of the push rod 32 is shown by a heavy broken line in Fig. 5. The transfer lever 42 now remains inoperative until a spring blank 12 is finish-wound, which state is determined by means of the proximity sensor 29. Compressed air is now applied to the cylinder-piston unit 28, whereby the pivoted lever 30 is actuated. Via the lever arm 30b, the pivoted lever 30 moves the push rod 32 in a roughly axial direction, whereby the flange 47 is moved in the direction of the arrow 50. Consequently, one of the knife-like end portions of the transfer lever 42 is engaged between two coils of the spring blank 12, whereby the spring blank 12 is held on the transfer lever 42. Immediately following this, the blank is parted from the wire 6 by means of the lever arm 30a and the cut-off knife 26, and thereby released. Since the push rod 32 is also in abutment with the stop 49, it is not only displaced axially, but also pivoted to some extent, so that before the end of its stroke, it slides out of the abutment 47a and releases the flange 47. The continuously driven sprocket wheel 39 can now once more drive the transfer arm 42, via the friction clutch 43, in the direction of the arrow 48, until, after rotating through 1800, the arm 42 is again stopped, owing to the push rod 32, which has meanwhile returned to its initial position, striking against the abutment 47a. Meanwhile, a further spring blank 12 has been wound, and the described process recommences. The spring blank 12, held on the end of the transfer lever 42, is moved through 1800 by rotation of the transfer lever. It comes into the region of two loop forming appliances 3a and 3b (Figs. 2, 5 and 7), in the position in which the other end of the transfer lever is inserted into the as yet unparted spring blank 12. The construction of the loop forming appliances is known, and is described, for example, in German Patent Application 1,883,011. They comprise an anvil and a driven ram for forming the hooklike loops on the ends of the spring blank 12. Since the loop forming appliances are not pertinent to the invention, they are not further described. An essential feature is, however, that they both engage the two ends of the spring blank and form the loops simultaneously. Thus, the forces applied to the spring blank balance each other out. On completion of the formation of the loops, the transfer lever 42, driven by means of the friction clutch, is detached from the finished spring. The spring is then released and delivered into a collecting bin.The loop forming appliances are pivotable with respect to the machine frame 1, so that it is possible to arrange the two loops at the ends of the spring in one plane. or in two planes perpendicular to each other. WHAT WE CLAIM IS:-

1. A machine for the coiling of helical springs having mutually abutting coils, and for the formation of loops at both ends of the springs, of the kind in which the spring wire which is to be coiled is periodically pushed by means of feed rollers and a guide against coiling fingers, which coil it in the form of a helix, the spring blank being cutoff from the wire by means of a cut-off knife, wherein a two-armed transfer lever for the spring blanks is arranged on a shaft driven by means of the driving motor of the machine, the lever arms of the transfer lever extending at an angle of 180C with respect to each other, and being provided with knife-like surfaces, to permit either lever arm to engage between two coils of a respective spring blank to hold the bland on the lever arm, before the cutting-off of the blank, and wherein, following the cutting-off of the spring blank, the transfer lever together with the spring blank engaged thereon is rotated through 1800 by means of its shaft to a position in which the loops can be produced simultaneously, by means of loop forming appliances at both ends of the spring blank supported on the respective transfer lever arm.

stroke of the push rod against one of the abutments on the flange.

3. A machine according to claim 1, wherein adjacent to the spring coiling mechanism there is arranged an inductive proximity sensor which switches off the drive to the coiling mechanism on the attain ment of the predetermined length of coil.

4. A machine for the coiling of helical springs substantially as hereinbefore described with reference to the accompanying drawings.