SU110996A1 - Method of pressing silver contacts - Google Patents

Description

In the production of contact springs with silver contacts, a considerable part of the time and labor is spent on inserting silver contacts into springs and ripping them up.

In the described method, in order to eliminate the need for pre-making contacts in the form of rivets, it is proposed to cut the silver wire into the holes of the contact springs by sequential operations: first by pressing through the steel cylinder, then by landing the contact head.

FIG. Figure 1 shows a schematic of the process with the proposed method of pressing silver contacts; in fig. Figure 2 shows a stamp that presses silver into the spring holes in two projections in vertical section.

In operation / (Fig. 1), silver is pressed into the spring holes: a-start of indentation, b-end of indentation.

In operation //, pre-molding (heading) the contact head is performed. Preforming is necessary to obtain a high-quality spherical part of the contact head.

At the /// operation, the contact head is finally formed. The indentation of silver is accomplished by the stamp shown in FIG. 2

The lower part of the stamp consists of the base /, the strip 2, the stop 5, the lower die 4 and the guides 5.

The middle part of the stamp consists of a strap 6, bushings 7, springs 8, pillars 9, guides 10, strap 11, abutment 12, frame 13, upper matrix 14, strap 15, springs 16 and knife 17. The devices 18 are attached to the middle part 19 for feeding wire, interconnected by a tightly wound spring 20, through which silver passes through the wire.

The upper part of the stamp consists of a strip 21, guide columns 22, a wedge 23, a punch holder 24 and a punch 25.

The bottom part is attached to the press table, and the top to the press ram.

No. 110996

The middle part of the stamp under the action of springs 8 is pressed against its lower part. -1

With the help of a punch, a piece of silver cut off from the wire is pressed through the matrix pressed against the spring into the spring holes, and thus a contact blank is obtained. When the silver on the wire is in its initial position, the die 14 is pressed by a press, which, using a lever system, lowers the raised middle part of the stamp through the uprights 9. At the same time, the spring 20 is connected, which is connected to the devices 18 and 19 for feeding silver wire. When the upper part of the stamp and the stop 26 are lowered, the devices 18 and 19 for feeding the wire, which inserts the silver wire into the holes of the knife 17, are lowered under the pressure of the spring 20.

The thickness of the knife is designed so that the cut off volume of silver corresponds to the volume of the finished contact.

In the extreme right position, the hole of the knife coincides with the holes in the die 14 and the guide bar 15. The upper part of the blade goes down and reaches the lower end position. In this position, the extruded silver is pushed out of the upper matrix 14. This is achieved as follows.

The upper part of the chip and the punch 25 in this position rise relatively slowly, while the middle part of the punch rises much faster and surpasses the upper part. When the gap between the spring and the upper die 14 reaches 3.5-4 mm, the rise of the middle section is stopped. This is quite enough to push the silver out of the matrix. The upper part of the belt continues to lift up and the spring 16, pressing the knife 17, moves it to the left. The remaining parts of the tag remain in the same position.

The knife stop is designed so that in the extreme left position of the knife // the hole in it coincides with the hole for supplying silver in the bar 15. This position corresponds to the initial position of the stamp.

A regular contact with a spherical head is obtained from the obtained cylindrical contact blank with the help of heading plates on a solenoid, eccentric, manual or other press.

Subject invention

A method of pressing silver contacts in contact springs, characterized in that, in order to eliminate the need for making contacts in the form of rivets, pieces of silver wire are pressed into the holes of the contact springs by successive operations, first pressing through a steel cylinder, then disembarking the contact head.