EP0131159B1

EP0131159B1 - Method and device for making grooves in a tin body

Info

Publication number: EP0131159B1
Application number: EP84106484A
Authority: EP
Inventors: Willem Pieter Post
Original assignee: Thomassen and Drijver Verblifa NV
Current assignee: Thomassen and Drijver Verblifa NV
Priority date: 1983-06-09
Filing date: 1984-06-06
Publication date: 1987-09-23
Also published as: DE3466360D1; EP0131159A3; EP0131159A2; NL8302057A; ATE29847T1

Abstract

In the wall of the tin body grooves are introduced between tools radially movable in opposite senses towards the tin body, one tool being provided with ridges and the other with grooves registering with the ridges. This method makes it possible, contrary to the usual rollers, to introduce grooves with fairly small tolerances. Damage of the lacquer does not occur. Because of the forming of sharper grooves the radial strength will be improved and the wall thickness of the tin body can be reduced.

Description

The invention relates to a method and an apparatus for pressing at least one in- or outwardly protruding reinforcing ridge in the sleeve of a tin body, that means to a method and a device of the kind as disclosed in US-A-4,380,165. The method published by this patent specification comprises a step of inserting the tin body axially into a gap left free between two similar radially spaced concentric closed curved or bent series of simultaneously radially reciprocatable stamps, the stamps of one series having on their faces confining said gap ridges which form together at least one row of longitudinally aligned ridges, the stamps of the other series having in their faces confining said gap grooves which form together at least one row of longitudinally aligned grooves registering with said ridges and the stamps of either series being provided with cam faces for cooperation with cam faces of respective axially reciprocatable control members, the cooperation of the cam faces of the stamps and those of the respective control members being such, as to ensure that the active strokes of said members have the effect of bringing the grooved stamps ahead of or simultaneously with the ridged stamps into engagement with the tin body, of blocking the radial disengagement movement of the grooved stamps and of forcing, by means of the ridged stamps, the tin body into the grooves of the grooved stamps, and subsequent steps of moving the control member of the grooved stamps axially to bring said stamps into engagement with the tin body and to block them in their positions of engagement, of moving the control member of the ridged stamps axially to force the tin body into the grooves of the blocked grooved stamps, of retracting the control members axially to enable the stamps of both series to be radially retracted from the tin body and of removing the tin body axially out of the gap left free again between the two series of radially retracted stamps.
In this known method cooperating bevelled cam faces provided on the grooved stamps and their control member are not only used for the conversion of the axial movement of said member into the radial movement of said stamps, but also for blocking said stamps in their positions of engagement with the tin body. This implies that both the radial displacement and the blocking of the grooved stamps depend on the exact adjustment of the end of the active axial stroke of said control member. This exact adjustment is in practice realized by means of stops. However, this way of defining the blocking end position of the control member in question has several disadvantages. Firstly, there is not much room to build such stops in. Secondly, the impact of the control member on the stops causes shocks in the apparatus which prevent high speeds of the actual pressing operation. Thirdly, the use of stops requires a resilient drive of the control member and such a drive in combination with stops present the possibility of rebounding, whereby the exact adjustment of the end of the active stroke of said member is affected which only can be prevented by relatively slow motion of the moving parts.
The invention has the object to improve this method and this is achieved in that only a first part of the active stroke of the control member of the grooved stamps is used to bring said stamps into engagement with the tin body, at the end of said part of the stroke the radial disengagement movement of said stamps is blocked and said blocking is maintained during the subsequent part of the stroke of said member. This improvement makes the length of the stroke of the control member of the grooved stamps independent of the blocking of said stamps, consequently noncritical, so that, even if stops at the end of the active stroke of said member should be used, the rebounding thereof by said stops, if kept within the second part of said stroke, would not have any effect on the blocking of the stamps in question. In many cases such stops may be dispensed with and this makes it possible to drive the control member of the grooved stamps positively, that means without the interposition of springs in the active direction. Due to these facts the speed of operation may be considerably increased.
The method can be carried out by an apparatus which, just as the apparatus described in US-A-4,380,165, comprises two similar radially spaced concentric closed curved or bent series of simultaneously radially reciprocatable stamps, the stamps of one series having on their faces confining the gap left free between the two series of stamps to receive the sleeve of a tin body ridges which form together at least one row of longitudinally aligned ridges, the stamps of the other series having in their faces confining said gap grooves which form together at least one row of longitudinally aligned grooves registering with said ridges, two axially movable control members, one for the simultaneous radial movement of the ridged stamps and one for the simultaneous radial movement of the grooved stamps, the ridged stamps on one hand and the respective control member on the other hand and the grooved stamps on one hand and the respective control member on the other hand being provided with cooperating cam faces, of which at least portions are bevelled for the conversion of the axial movements of the control members into radial movements of the two series of stamps towards one another in order to bring the grooved stamps into engagement with a tin body inserted into the said gap and to force by means of the ridges of the ridged stamps the tin body into the grooves of the grooved stamps, when the latter are held in their positions of engagement with the tin body, and the cam faces of the grooved stamps and their control member are also shaped to block the radial disengagement movement of the grooved stamps when loaded by the pressing ridged stamps, means for moving the control members axially and transporting means for moving a tin body axially into and out of the gap left between the two series of stamps after they have been radially moved away from one another, but said known device being improved in that of each pair of cooperating cam faces of which one is formed on a grooved stamp and the other one on the respective control member, at least one cam face has a bevelled portion for bringing said stamps into engagement with the inserted tin body during a first part of the active axial stroke of said control member and at least the other cam face has an axially extending portion for blocking the radial disengagement movement of said stamp at the end of said first part of the stroke and for maintaining said blocking during the subsequent part of said stroke.
The reinforcing ridge or ridges to be produced in the tin body may be other than purely circumferential, e.g. sloping, rhombic or otherwise different.
It appears to be advantageous to provide the improved apparatus with at least one axially movable spring loaded stop member for limiting the axial insertion of the tin body into the gap between the two series of stamps by said transporting means and for ejecting the tin body out of said gap after the pressing operation has been completed.
The invention will be described more fully with reference to the drawings, which show in

Figs. 1 to 4 different positions of stamps making grooves in a tin body when the method embodying the invention is being carried into effect,.
Fig. 5 schematically the supply of tins to the device embodying the invention,
Fig. 6 a sectional view of the device embodying the invention,
Fig. 7 on an enlarged scale part of the device of Fig. 6,
Fig. 8 a sectional view taken on the line VII-I-VIII in Fig. 7,
Fig. 9 is a sectional view like Fig. 7 in the closed position of the device,
Fig. 10 a sectional view taken on the line X-X in Fig. 9.

In accordance with the method embodying the invention (see Figs. 1 to 4) a tin body 1 is introduced between two stamps 2 and 3, one stamp 2 having ridges 4 and the other stamp 3 having grooves 5 registering with the ridges. The stamps 2 and 3 are driven by first and second driving means 6 and 7 respectively. The driving means 6 and 7 and the co-operating faces of the stamps 2 and 3 are formed so that during the first part of the axially directed stroke of the driving means 6, 7 (see Fig. 2) the stamps 2 and 3 are radially moved towards one another, whereas during the last part of the stroke (see Fig. 3) solely stamp 2 is radially moved and hence stamp 3 serves as a counter-bearing. The radial movement producing the grooves in the tin body 1 is, therefore, performed solely by stamp 2. After the formation of the grooves the driving means 6, 7 (see Fig. 4) move in opposite axial directions, the stamps 2 and 3 move radially in opposite senses and the tin body is again released.
Fig. 5 schematically shows the way in which tins 1 are fed to a device as shown in Figs. 6 and 7 in which the assembly of Figs. 1 to 4 is arranged. The tins (Fig. 5) are moved by a worm conveyor 8 in a feeder 9 into a device embodying the invention, which comprises in this embodiment six identical processing stations 10.
With the aid of the feeder 9 (see Fig. 6) a tin body 1 is moved to a processing station 10. The unit with the stamps is fixed by means of a cap nut 12 to a plunger housing 13 of an upper plunger 14. The plunger 14 is driven by a profiled upper disc 15 and a roller 16. The tin body 1 is moved upwards by means of a lower plunger 17 driven by a lower disc 18 into the unit 11. The tin body 1 is then enclosed in the feed head 19. The upper part can be set in height with the aid of a setting spindle 20. In this way the desired setting for the tin height can be chosen. Since the upper part is adjustable, there is no need for setting a lower part and hence of the feeding part of the tin bodies.
From Figs. 7 to 10 it will be apparent that the tin body 1 is introduced into the gap between the stamps 2 and 3 up to a resilient stop 22. After the process the spring 23 ensures the ejection of the tin body. The driving means for the stamps 2 and 3, and 6, 7 respectively and the part 24 are fastened to the plunger 14 with the interposition of a spring structure 25. The cylindrical part 21 serves as a guide for the moving parts. During the performance of a stroke of the plunger 14 the driving means 6 and 7 move the stamps 2 and 3 in a manner such that the stamps 3 move radially outwards and engage the tin body. The stroke of the driving means 7 is limited by the stop 26. During the remaining part of the stroke of the plunger 14 the driving means 6 for the stamps 2 are moved axially so that the stamps 2 perform a radially inward movement and make the grooves in the tin body 1, whilst the inner stamps 3 serve as counter-bearings. Subsequently the plunger 14 moves in the opposite axial direction so that again a gap is formed between the stamps 2 and 3. The tin body is then moved to the outside by the head provided with magnets.
Fig. 8 shows that the stamps 2 and 3 are disposed opposite one another in segments of a circle.

Claims

1. A method of pressing at least one in- or outwardly protruding reinforcing ridge in the sleeve of a tin body (1), said method comprising a step of inserting the tin body (1) axially into a gap left free between two similar radially spaced concentric closed curved or bent series of simultaneously radially reciprocatable stamps (2, 3), the stamps (2) of one series having on their faces confining said gap ridges (4) which form together at least one row of longitudinally aligned ridges, the stamps (3) of the other series having in their faces confining said gap grooves (5) which form together at least one row of longitudinally aligned grooves registering with said ridges, and the stamps (2, 3) of either series being provided with cam faces for cooperation with cam faces of respective axially reciprocatable control members (6, 7), the cooperation of the cam faces of the stamps (2, 3) and those of the respective control members (6, 7) being such as to ensure that the active strokes of said members (6, 7) have the effect of bringing the grooved stamps (3) ahead of or simultaneously with the ridged stamps (2) into engagement with the tin body (1), of blocking the radial disengagement movement of the grooved stamps, (3) and of forcing, by means of the ridged stamps (2), the tin body (1) into the grooves (5) of the grooved stamps (3), and subsequent steps of moving the control member (7) of the grooved stamps (3) axially to bring said stamps (3) into engagement with the tin body (1) and to block them in their positions of engagement, of moving the control member (6) of the ridged stamps (2) axially to force the tin body (1) into the grooves (5) of the blocked grooved stamps (3), of retracting the control members (6, 7) axially to enable the stamps (2, 3) of both series to be radially retracted from the tin body (1) and of removing the tin body (1) axially out of the gap left free again between the two series of radially retracted stamps (2, 3), characterized in that only a first part of the active stroke of the control member (7) of the grooved stamps (3) is used to bring said stamps (3) into engagement with the tin body (1), at the end of said part of the stroke the radial disengagement movement of said stamps (3) is blocked and said blocking is maintained during the subsequent part of the stroke of said member (7).

2. An apparatus for carrying out the method claimed in claim 1, said device comprising two similar radially spaced concentric closed curved or bent series of simultaneously radially reciprocatable stamps (2, 3), the stamps (2) of one series having on their faces confining the gap left free between the two series of stamps (2, 3) to receive the sleeve of a tin body (1) ridges (4) which form together at least one row of longitudinally aligned ridges, the stamps (3) of the other series having in their faces confining said gap grooves (5), which form together at least one row of longitudinally aligned grooves registering with said ridges, two axially movable control members (6, 7), one (6) for the simultaneous radial movement of the ridged stamps (2) and one (7) for the simultaneous radial movement of the grooved stamps (3), the ridged stamps (2) on one hand and the respective control member (6) on the other hand as well as the grooved stamps (3) on one hand and the respective control member (7) on the other hand being provided with cooperating cam faces, of which at least portions are bevelled for the conversion of the axial movements of the control members (6, 7) into radial movements of the two series of stamps (2, 3) towards one another in order to bring the grooved stamps (3) into engagement with a tin body (1) inserted into the said gap and to force by means of the ridges (4) of the ridged stamps (2) the tin body (1) into the grooves (5) of the grooved stamps (3), when the latter (3) are held in their positions of engagement with the tin body (1), and the cam faces of the grooved stamps (3) and their control member (7) are also shaped to block the radial disengagement movement of the grooved stamps (3) when loaded by the pressing ridged stamps (2), means (12-16, 24, 25) for moving the control members (6, 7) axially and transporting means (17, 18, 19) for moving a tin body (1) axially into and out of the gap left between the two series of stamps (2, 3) after they have been radially moved away from one another, characterized in that of each pair of cooperating cam faces, of which one is formed on a grooved stamp (3) and the other one on the respective control member (7), at least one cam face has a bevelled portion for bringing said stamp (3) into engagement with the inserted tin body (1) during a first part of the active axial stroke of said control member (7) and at least the other cam face has an axially extending portion for blocking the radial disengagement movement of said stamp (3) at the end of said first part of the stroke and for maintaining said blocking during the subsequent part of said stroke.

3. An apparatus as claimed in claim 2, characterized in the provision of at least one axially movable spring (23) loaded stop member (22) for limiting the axial insertion of the tin body (1) into the gap between the two series of stamps (2, 3) by said transporting means (17, 18, 19) and for ejecting the tin body (1) out of said gap after the pressing operation has been completed.