US3724257A

US3724257A - Apparatus for manufacturing thin wall flexible bearing liners

Info

Publication number: US3724257A
Application number: US00181548A
Authority: US
Inventors: A Sims; S Sharp
Original assignee: Vandervell Products Ltd
Current assignee: Federal Mogul Shoreham Ltd
Priority date: 1971-09-17
Filing date: 1971-09-17
Publication date: 1973-04-03
Anticipated expiration: 1990-04-03

Abstract

An apparatus for producing thin wall flexible bearing liners has a press for bending and coin pressing strip bearing material and ram operated tools for piercing oil holes in the strip and finally severing the strip into bearing liners. The rams for the tools are controlled by the press to operate before or after coin pressing so that the tools do not impede elongation of the strip due to the coin pressing.

Description

United States Patent 91 Sims et al.

[ 1 Apr. 3, 1973 [54] APPARATUS FOR MANUFACTURING THIN WALL FLEXIBLE BEARING LINERS [75] Inventors: Arthur Albert Sims, South Harrow; Stanley Gordon Sharp, Maidenhead, both of England [73] Assignee: Vandervell Products Maidenhead, England 22 Filed: Sept. 17,1971

21 Appl.N0.: 181,548

Limited,

[52] US. Cl. ..72/324, 29/149.5, 29/630, 72/335, 72/336, 72/339 [51] Int. Cl. ..B2ld 43/28 [58] Field of Search .29/149.5 R, 149.5 C, 149.5 DP, 29/1495 S, 149.5 NM, 149.5 PM; 72/19, 20,

[56] References Cited UNITED STATES PATENTS 3,545,248 12/1970 Whiteside ..72/324 Primary Examiner-Richard J. l-lerbst Assistant Examiner-James R. Duzan AttorneyJoh-n A. Mawhinney [5 7] ABSTRACT An apparatus for producing thin wall flexible bearing liners has a press for bending and coin pressing strip bearing material and ram operated tools for piercing oil holes in the strip and finally severing the strip into bearing liners. The rams for the tools are controlled by the press to operate before or after coin pressing so that the tools do not impede elongation of the strip due to the coin pressing.

21 Claims, 9 Drawing Figures PATENTEUAPRB I975 3.724.257

SHEET 2 OF 5 PATENTEDAPRCi I975 3,724,257

SHEET 3 [IF 5 PATENTED APR 3 I973 SHEET UF 5 APPARATUS FOR MANUFACTURING THIN WALL FLEXIBLE BEARING LINERS This invention relates to apparatus for making thin wall flexible bearing liners and is an improvement in the invention claimed in US. Pat. No. 3,516,137.

The invention provides an apparatus for making thin wall flexible bearing liners comprising a press, means to feed a strip of bearing material through the press step by step, a press tool operated by the press for rendering successive portions of the strip of bearing material arcuate across the strip and coin pressing the outer surfaces of the arcuate portions to the required finish, and a severing tool for severing the coin pressed arcuate portions from the strip characterized in that the severing tool is operated by a separate power device which is timed in accordance with the press to operate at a different time from when the press tool acts on and causes elongation of the strip.

The power device for the severing tool preferably comprises a fluid pressure operated ram connected to a source of fluid pressure controlled by the press.

In the latter case the fluid pressure operated ram for the severing tool may be a slave cylinder and a master cylinder may be provided which is connected to the slave cylinder, the master cylinder being operated in timed relation with the press.

A capsule may be provided comprising two relatively reciprocable members, the severing tool is mounted on one of the members and the slave cylinder is arranged to move said one member and the severing tool in a direction to effect a severing operation.

In one arrangement an additional slave cylinder may be provided for returning the said one member and severing tool after the severing operation and means are provided for supplying fluid at a constant pressure which is less than that supplied by the aforesaid master cylinder to the additional slave cylinder so that the additional slave cylinder provides a biasing force urging the member away from the severing position which force is overcome by operation of the slave cylinder connected to the master cylinder.

Alternatively spring means may be provided for returning the one member and severing tool after the severing operation.

Driving means may be provided for operating the press and a cam driven by said driving means is provided for operating the master cylinder at the appropriate point in the operation of the press.

The driving means for the press may comprise a crankshaft which drives the cam for the master cylinder.

In any of the above arrangements a tool for forming a locating notch in each arcuate portion may be associated with the severing tool and further power device is provided for operating the notching tool at different times from when the press tool acts on and causes elongation of the strip.

The notching tool may be arranged to be operated immediately after the severing tool.

Preferably the notching tool is operated by a further slave cylinder, said slave cylinder is connected to the aforesaid master cylinder and a control valve operated by the press is provided in the connection of the master cylinder to the further slave cylinder, the control valve being operated by the press to open the valve after the severing tool has operated to operate the notching tool.

In the case where means are provided for supplying fluid at a constant pressure to a slave cylinder for returning the severing tool after a severing operation, a slave cylinder may also be provided for withdrawing the notching tool after a notching operation which slave cylinder is connected to said means for supplying fluid at constant pressure.

In the case where the severing tool is mounted in a capsule, the notching tool and its associated power device may also be mounted in the capsule.

In any of the above arrangements the severing tool may be timed to be operated by the power device when the strip is stationary before the press tool starts to operate, before or after the press tool acts on and causes elongation of the strip.

At least one tool may be provided for piercing an oil hole in each arcuate portion of the strip before the arcuate portion is severed from the strip and a power drive is provided for operating the piercing tool which further power device is timed in accordance with the press to operate at a different time from when the press tool acts on and causes elongation of the strip.

The piercing tool may be operated by a slave cylinder connected to the aforesaid master cylinder or a further master cylinder operated by the press.

In the case where a further master cylinder is provided a cam may be provided for operating the master cylinder at the appropriate time which cam is driven by the drive means for the press.

The further master cylinder for the piercing tool and the master cylinder for the severing tool may be timed to operate at the same time.

Two piercing tools may be provided each having a slave cylinder connected to the master cylinder.

A capsule may be provided for the or each piercing tool comprising a base on which an upstanding arcuate bridge is mounted, the power device for the or each piercing tool being mounted on the bridge to direct the piercing tool radially inwardly of the bridge to pierce an arcuate portion located on the base' under the bridge.

In the case where means are provided for supplying fluid under constant pressure to a slave cylinder for returning the severing tool from the operative position the slave cylinder for the or each piercing tool may be a double acting cylinder and is connected to said means for supplying fluid under constant pressure to withdraw the or each piercing tool after piercing.

The following is a description of some specific embodiments of the invention reference being made to the accompanying drawings in which:

FIG. 1 is a diagrammatic side elevation of a press and press tools certain of which are located in separate capsules and are ram operated for making thin wall flexible bearing liners;

FIG. 2 is a section through one capsule on the line 2-2 of FIG. 1-,

FIG. 3 is a section through another capsule on the line 3-3 of FIG. 1;

FIG. 4 is a sectional view of the capsule shown in FIG. 3 taken in a transverse plane;

FIG. 5 is a diagrammatic view of the ram operated tools of FIG. 1 and a fluid circuit connected to the rams; 3

FIG. 6 is a diagram illustrating the cycle of operation of the press tools; a

FIG. 7 is a similar view to FIG. showing an alternative fluid circuit;

FIG. 8 is a diagrammatic view of an alternative form of capsule to that of FIG. 2; and

FIG. 9 is a diagrammatic view of an alternative form of capsule to that of FIG. 3.

The apparatus comprises a press having a lower fixed platten 10 and upper vertically reciprocating platten 11 driven by a crank mechanism which will be referred to later. A capsule indicated generally by the reference numeral 12 is mounted between the platens of the press. The capsule is identical to the first capsule of the press described in our US. Pat. No. 3,5 l6,l37. As described in the latter specification the capsule comprises upper and

lower members

13 and 14 which are fixed, respectively, to the reciprocating and fixed platens of the

press

11 and 10. Mounted on the

members

13 and 14 are

tools

14, 15 for indenting flat strip bearing material on either side across its width, a tool 16 for stamping a trade mark on the strip,

tools

17, 18 for reducing the width of the strip,

tools

19, 20 for rendering a central portion of the strip and partially severing a portion from the strip and

tools

21, 22 for rendering the portions fully arcuate and then coin pressing the arcuate portions to the required circumferential length and external surface finish and shape.

The bearing material is indicated at 22 and is fed step by step, each step corresponding in length to the required axial length of the bearing liners to be formed, by a pair of

co-operating rollers

23, 24. The reciprocating platen 1 1 of the press is timed with the drive for the

rollers

23, 24 to bring the aforesaid tools contained in the capsule into operation on the strip whilst the strip is stationary between movements, as described later.

In the apparatus described in US. Pat. No.-

3,516,137. the arcuate strip is then passed to first a capsule which pierces oil holes in the strip and then a capsule which severs arcuate portions from the strip and forms a notch in one circumferential edge of the strip, both the latter capsules being operated by the reciprocating platten 11 of the press on the upward stroke of the press. Thus the tools in the latter capsules are free of the strip when the strip is coin-pressed by the

tool

21, 22 of the capsule 12 which results in slight elongation of the strip. In the apparatus according to the present invention the tools of the capsules for formingan oil hole in the arcuate portions of the strip, severing the arcuate portions of the strip and forming a notch in the portions of the strip are operated by separate slave cylinders which are controlled by movement of the press crankshaft instead of by direct operation of the press.

The capsule according to the present invention for piercing an oil hole in each arcuate portion of the strip will now be described with reference to FIGS. 1 and 2 of the drawings. The capsule is indicated generally at 25 of H6. 1, and comprises a base member 26 which is bolted to the platen 10 of the press on which two axially spaced bridge members 27 are mounted to extend over the arcuate strip. A slave cylinder 28 is mounted between the two bridge members 27. The ram comprises a slave cylinder 29 having ports 30 at both ends thereof for connection to sources of oil under pressure as described later. The cylinder contains a piston 31 having an integral piston rod 32 which extends downwardly from the lower end of the cylinder and is formed at its lower end with an integral T-shaped head 33. A pressure pad 34 is connected to the head 33 by bolts 35 which permit the pad to have limited movement towards and away from the head. The underside of the pad is formed with a central downwardly facing part cylindrical seat 36 for engaging the upper surface of the arcuate strip 22. The strip 22 is supported from below by a cylindrical block 37 mounted on an insert 38 secured to the base 26.

A piercing tool 39 is mounted at the lower end of a holder 40 which projects from blind bore 41 formed in the underside of the head 33. The piercing tool 39 extends through a bore 42 in the pad 34 and the upper end of the bore 42 is counter-bored to receive the lower end of the holder 40. When the pad 34 is located at its limit of movement away from the head 33 as shown in the drawing the lower end of the piercing tool is flush with the surface of the seat 36 and the lower end of the holder 40 is spaced from the bottom of the counter-bore.

The piercing tool holder 41 is flanked on either side by plungers 43 located in cylinders 44 formed in the head 33 and which plungers bear on the upper surface of the pad 34. A passageway 45 extends from one side of the piston rod 32 adjacent the piston 31 axially along the piston rod and then divides in the head 33 to lead to both the cylinders 44.

When oil pressure is supplied to the upper end of the slave cylinder 29 to the bore 30 as described later the piston 31 is displaced downwardly thereby firmly engaging the seat 36 of the pad 34 against the upper surface of the arcuate portion of the strip. Further downward movement of the piston 31 drives the piercing tool 39 through the arcuate portion of the strip to form an oil hole.

The block 37 has a projection opposite the piercing tool shaped to form a recess around the hole formed in the arcuate portion by the piercing tool when the arcuate portion is pressed against the anvil. The projection has a bore to receive the slug pressed from the arcuate portion and the piercing tool. The downward movement of the piston continues until the lower end of the tool holder 40 engages at the bottom of the counterbore in the 34. Oil pressure to the upper end of the cylinder is then released and oil pressure applied to the lower end of the cylinder to raise the piston 31 to withdraw the piercing tool from the strip. As soon as the piston rod 32 has been raised sufficiently for the upper end of the passage 45 to communicate with the lower end of the cylinder oil passes down the passage 45 to the plungers 43 which push the pad 34 downwardly with respect to the head 33 to retract the piercing tool into the bore 42 in the pad thereby stripping the tool from the arcuate strip.

Reference is now made to FIGS. 1 3, and 4 of the drawings which show the capsule for severing the arcuate portions from the strip and forming a notch in the circumferential edge of the strip. The capsule is indicated generally by the reference numeral 50 and comprises a lower base member 51 and an upper member 52 which is fixed to the base member 51 by two pillars 53 spaced on either side of the strip.

A tool carrier 54 is slidably mounted on the pillars 53 and an upper die-part 55 is secured to the underside of the tool carrier 54. The die-part 55 is formed with a semi-cylindrical recess 56 the circumferential edge of which adjacent the piercing capsule 25 provides a shearing edge which co-operates with a shearing edge on a semi-cylindrical support (not shown) which is mounted on the base 51 to complete severing of an arcuate portion from the strip.

The upper member 52 of the capsule is formed with a downwardly open slave cylinder 57 containing a piston 58 which bears on the upper end of the tool carrier 54. The cylinder receives oil under pressure through a port 59 to displace the piston 58 and thereby the tool carrier 54 and die-part 55 downwardly to complete the severing of the strip between edges and arcuate portions.

This operation is carried out at the same time as the piercing operation carried out in the aforesaid piercing capsule.

As the arcuate portion is moved downwardly by the die-part 55 it compresses two horizontally acting spring loaded pressure members 100 (only one can be seen). When the severing of the portion from the strip is complete the pressure members 100 push the arcuate portion axially along the recess in the die-part until it engages a shoulder in the die-part which locates the arcuate portion for a notching operation. The notching operation is performed by a notching tool 60 which projects from a recess 61 in the lower member 51 of the capsule. The tool 60 is mounted on a rod 62 which extends through a bore 63 in the member 51. The rod 62 projects from either end of the memberSl and each end of the rod carries a piston 64. The pistons 64 are located in slave cylinders 65 secured to the ends of the member 51. The cylinders 65 have ports 66 through which oil can be supplied under pressure to the cylinders. Oil under pressure is supplied to the left-hand cylinder 65 the piston rod 62 and with it the notching tool 60 are moved to the right to perform a notching operation. A recess 67 is formed at one circumferential end of the die-part to receive a bent out notch. Oil under pressure is supplied to the cylinder 65 at the lefthand end of the capsule as shown in FIG. 3 to move the piston 64 and thereby the notching tool 60 to the right to perform the notching operation. The die-part 55, the tool 60 an arcuate portion of the strip 68 are indicated in dotted outline on FIG. 3 at the completion of the notching operation in which a notch indicated at 69 has been pressed outwardly from the circumferential edge of the arcuate portion into the recess 67 to the die-part. Fluid pressure to the left hand cylinder 65 is then cut off and is transferred to the right hand cylinder to withdraw the notching tool 60.

The tool carrier 54 is also provided with two downwardly open cylinders 70 in which fixed piston members 71 which stand upwardly from the member 51 of the capsule engage. Oil is supplied under pressure to the cylinder 70 through ports 72 to raise the tool carrier 54 simultaneously with withdrawal of the notching tool 60.

The oil pressure supply system for the various cylinders of the

capsules

25 and 50 will now be described with reference to FIG. 5 of the drawings.

The system comprises an air/oil intensifier 73 which receives oil from a reservoir (not shown) and air under pressure through a conduit 74. The intensifier provides an output of oil under pressure which is determined by the air pressure.

The intensifier has an outlet which is connected to two

output lines

76, 77. The outlet is also connected through a valve to the reservoir which is held open by a spring. The valve is arranged to close if pressure in the outlet of the intensifier rises sufficiently to overcome the springpressure acting on the valve.

The output line 76 is connected in series to a master cylinder 78, the top of slave cylinder 57 and, through a solenoid controlled valve 101, to the left hand slave cylinder 65 of capsule 50. The solenoid controlled valve is connected to a limit switch which is opened and closed by the reciprocating platen 11 of the press. or by a cam fitted to the crankshaft The limit switch is arranged to be closed by the platen crankshaft cam to open the valve 101 after an arcuate portion has been severed from the strip and the arcuate portion has been moved to the notching position by the pressure member 100. The output line 77 is connected in series to master cylinder 79 and the top of slave cylinder 29 of capsule 25.

The master cylinders have projecting

push rods

80, 81 which, when depressed into the cylinders, raise the pressure in the

output lines

76, 77 sufficiently to close the valve in the outlet of the intensifier 73. The full output pressure of the intensifier raised further by the master cylinders is then applied to the upper end of the slave cylinder 29 to effect a piercing operation, to the upper end of the cylinder 57 to effect a severing operation and after sufficient time has elapsed for the severed portion to reach the notching position the limit switch is closed to open the valve 101 to the left hand cylinder 65 to effect a notching operation.

The

push rods

80, 81 of the master cylinders are depressed by

cams

82, 83 mounted on a part of the crankshaft 84 for reciprocating the upper platen of the press. The cams are arranged on the crankshaft to depress the push rods at the appropriate times as described later.

When the

cams

82, 83 release the push rods oil pressure in the master cylinders forces the push rods outwardly of the cylinders and as a result pressure in the

output liners

76, 77 drops sufficiently for the spring to open the valve in the outlet of the intensifier so that oil from both the intensifier and the output lines can drain to the reservoir.

The tools are then returned to their inoperative positions by oil pressure from a second air/oil intensifier. The intensifier 85 is similar to the intensifier 73 except that the outlet has a pressure relief valve connected to the reservoir. The intensifier has one output line 86 connected to the lower end of cylinder 29 of capsule 25 and a second output line 87 connected to the two slave cylinder and the right hand slave cylinder 65 of capsule 50. The intensifier delivers a constant pressure to the slave cylinders and any excess pressure is released to the reservoir through the relief valve.

Thus when pressure in the

output lines

76,77 drops after the tools in the capsules have performed their respective operations, the oil pressure from the intensifier causes the slave cylinders to return the tools to their inoperative positions. When the slave cylinders receive fluid pressure from the intensifier 73 and

master cylinders

78, 79 which in total provide a greater pressure than the intensifier 85, the slave cylinders act against the oil pressure from the intensifier 85 thus driving the fluid back towards the intensifier 85 and excess fluid escapes through the relief valve so that the oil pressure does not rise between the intensifier 85 and slave cylinders.

Reference is now made to FIG. 6 of the drawings which illustrates diagrammatically the cycle of operation of the press and the capsules 25 and S0. The circle represents one reciprocation of the press with the top of the circle representing top dead center of the platen 11 and the bottom of the circle representing bottom dead center of the platen. All the operations performed by the tools in the capsule 12 are carried out during a period staring 90 in advance of the bottom dead center of the platen 11 ending 91 after bottom dead center of the platen. The coin pressing of the arcuate portion by the tools 21 22 occurs over a period starting 25 before bottom dead center and ending 25 after bottom dead center of the platen 11. This leaves a period of 179 in which the platen 11 is moving up to and past top dead center for one feed movement of the strip 22 followed, during the last 25 of the 179 period by the piercing operation in the capsule 25 and the severing and notching operation in the capsule 50. The

cams

82 and 83 on the crankshaft 82 of the press are set to operate the

master cylinders

77, 79 so that the piercing, severing and notching tools all operate during this 25 period. Alternatively the piercing, severing and notching operations could be carried out either during a period between 90 and 25 in advance of bottom dead center of the press when the tools of the capsule 12 are moving into engagement with and operate on the strip or during a period between 25 and 91 after bottom dead center during which the tools of the capsule 12 are disengaging with the strip. It'is essential however that the tools for piercing, severing and notching do not engage the strip during the 25 of movement of the platen 11 on either side of bottom dead center of the platen when the coin pressing of the strip is being carried out.

Reference is now made to FIG. 7 of the drawings which shows a very similar arrangement to that shown in FIG. except that the second outlet line 78 of the intensifier 75 and associated master cylinder 79 and cam 83 are dispensed with and the'upper end of the cylinder 29 is connected in series with the master cylinder 78.

FIGS. 8 and 9 of the drawings show alternative forms of the

capsules

25 and 50 and like parts have been allotted the same reference numerals. Referring firstly to FIG. 8 which shows an alternative piercing capsule, two slave cylinders 90 are mounted at spaced locations around the bridge members 27 of the capsule. Each slave cylinder operates a piercing tool 91 to pierce an oil hole in the strip. Each slave cylinder is provided with a spring for retracting the piercing tool of the cylinder after effecting an operation. The two cylinders are connected to the output line from the output liners 76 from the master cylinder 78 in a similar manner to that described above.

FIG. 9 of the drawings shows an alternative severing and notching capsule. The tool carrier 54 in this case is driven downwardly by two slave cylinders 92 and returned upwardly by springs 93 encircling the cylinders. Also the notching tool 60 is operated by a slave cylinder 94 and returned by a spring (not shown). The slave cylinder 94 is arranged to operate the notching tool after completion of the severing operation. The arrangement is otherwise similar to that described with reference to FIGS. 1 and 3.

We claim:

1. An apparatus for making thin wall flexible bearing liners comprising a press, means to feed a strip of bearing material through the press step by step, a press tool operated by the press for rendering successive portions of the strip of bearing material arcuate across the strip and coin pressing the outer surfaces of the arcuate portions to the required finish, and a severing tool for severing the coin pressed arcuate portions from the strip wherein the improvement comprises providing a separate power device for operating the severing tool which is timed in accordance with the press mechanism to operate at a different time from when the press tool acts on and causes elongation of the strip.

2. An apparatus as claimed in claim 1 wherein the power device for the severing tool comprises a fluid pressure operated ram connected to a source of fluid pressure controlled by the press.

3. An apparatus as claimed in claim 2 wherein the fluid pressure operated ram for the severing tool is a slave cylinder and a master cylinder is provided which is connected to the slave cylinder, the master cylinder being operated in timed relation with the press.

4. An apparatus as claimed in claim 3 wherein a capsule is provided comprising two relatively reciprocable members, the severing tool is mounted on one of the members and the slave cylinder is arranged to move said one member and the severing tool in a direction to effect a severing operation. 5. An apparatus as claimed in claim 4 wherein an additional slave cylinder is provided for returning the said one member and severing tool after the severing operation and means are provided for supplying fluid at a constant pressure which is less than that supplied by the aforesaid master cylinder to the additional slave cylinder so that the additional slave cylinder provides a biasing force urging the member away from the severing position which force is overcome by operation of the slave cylinder connected to the master cylinder.

6. An apparatus as claimed in claim 4 wherein spring means are provided for returning the one member and severing tool after the severing operation.

7. An apparatus as claimed in claim 3 wherein driving means are provided for operating the press and a cam driven by said driving means is provided for operating the master cylinder at the appropriate point in the operation of the press.

8. An apparatus as claimed in claim 7 wherein the driving means for the press comprise a crankshaft which drives the cam for the master cylinder.

9. An apparatus as claimed in claim 1 wherein a tool for forming a locating notch in each arcuate portion is associated with the severing tool and a further power device is provided for operating the notching tool at a dififerent time from when the press tool acts on and causes elongation of the strip.

10. An apparatus as claimed in claim 9 wherein the notching tool is arranged to be operated immediately after the severing tool.

11. An apparatus as claimed in claim 9 wherein the notching tool is operated by a further slave cylinder, said slave cylinder is connected to the aforesaid master cylinder and a control valve operated by the press is provided in the connection of the master cylinder to the further slave cylinder, the control valve being operated by the press to open the valve after the severing tool has operated to operate the notching tool.

12. An apparatus as claimed in claim 11 and in the case where means are provided for supplying fluid a constant pressure to a slave cylinder for returning the severing tool after a severing operation wherein a slave cylinder is also provided for withdrawing the notching tool after a notching operation which slave cylinder is connected to said means for supplying fluid at constant pressure.

13. An apparatus as claimed in claim 9 and in the case where the severing tool is mounted in a capsule wherein the notching tool and its associated power device are also mounted in the capsule.

14. An apparatus as claimed in claim 1 wherein the severing tool is timed to be operated by the power device when the strip is stationary before the press tool starts to operate, before or after the press tool acts on and causes elongation of the strip.

15. An apparatus as claimed in claim 1 wherein at least one tool is provided for piercing an oil hole in each arcuate portion of the strip before the arcuate portion is severed from the strip and a power device is provided for operating the piercing tool which further power device is timed in accordance with the press to operate at a different time from when the press tool to the aforesaid master cylinder or a further master cylinder operated by the press.

17. An apparatus as claimed in claim 16 and in the case where a further master cylinder is provided wherein a cam is provided for operating the further master cylinder at the appropriate time which cam is driven by the drive means for the press.

18. An apparatus as claimed in claim 17 wherein the further master cylinder for the piercing tool and the master cylinder for the severing tool are timed to operate at the same time.

19. An apparatus as claimed in claim 16 wherein two piercing tools are provided each having a slave cylinder connected to the master cylinder.

20. An apparatus as claimed in claim 13 wherein a capsule is provided for the or each piercing tool comprising a base on which an upstanding arcuate bridge is mounted the power device for the or each piercing tool being mounted on the bridge to direct the piercing tool radially inwardly of the bridge to pierce an arcuate portion located on the base under the bridge.

21. An apparatus as claimed in claim 16 and in the case where means are provided for supplying fluid under constant pressure to a slave cylinder for returning the severing tool from the operative position wherein the slave cylinder for the or each piercing tool is a double acting cylinder and is connected to said means for supplying fluid under constant pressure to withdraw the or each piercing tool after piercing.

Claims

4. An apparatus as claimed in claim 3 wherein a capsule is provided comprising two relatively reciprocable members, the severing tool is mounted on one of the members and the slave cylinder is arranged to move said one member and the severing tool in a direction to effect a severing operation.

5. An apparatus as claimed in claim 4 wherein an additional slave cylinder is provided for returning the said one member and severing tool after the severing operation and means are provided for supplying fluid at a constant pressure which is less than that supplied by the aforesaid master cylinder to the additional slave cylinder so that the additional slave cylinder provides a biasing force urging the member away from the severing position which force is overcome by operation of the slave cylinder connected to the master cylinder.

9. An apparatus as claimed in claim 1 wherein a tool for forming a locating notch in each arcuate portion is associated with the severing tool and a further power device is provided for operating the notching tool at a different time from when the press tool acts on and causes elongation of the strip.

15. An apparatus as claimed in claim 1 wherein at least one tool is provided for piercing an oil hole in each arcuate portion of the strip before the arcuate portion is severed from the strip and a power device is provided for operating the piercing tool which further power device is timed in accordance with the press to operate at a different time from when the press tool acts on and causes elongation of the strip.

16. An apparatus as claimed in claim 15 wherein the piercing tool is operated by a slave cylinder connected to the aforesaid master cylinder or a further master cylinder operated by the press.