GB2200192A

GB2200192A - Device for the rapid change of cams in a press for the production of rivets and the like

Info

Publication number: GB2200192A
Application number: GB08730322A
Authority: GB
Inventors: Garlaschi Eufemia
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-12-31
Filing date: 1987-12-30
Publication date: 1988-07-27
Anticipated expiration: 2007-12-30
Also published as: FR2608949B1; GB2200192B; ES2008403A6; IT8624341V0; DE8717069U1; GB8730322D0; FR2608949A1; IT209421Z2

Abstract

In a press for the production of solid rivets, partially bored rivets, and the like, a revolving shaft 13 has at least one removable cam 15, mounted in a complementary seat on the shaft in abutment with a stop collar 19 integral with the shaft, and a sleeve element 34 is shiftable hydraulically on a bush 18 along the shaft between a first position, in which the cam is locked, and a second position, in which the cam is disengaged. <IMAGE>

Description

DEVICE FOR THE RAPID CHANGE OF CAMS IN A PRESS FOR THE PRODUCTION ON RIVETS AND THE LIKE".

The present invention relates to a device for the rapid change of cams in a press for the production of solid rivets, partially-bored rivets, tubular rivets, and the like.

In a press for the production of partially-bored rivets, such as, e.g., the press disclosed in U.S. patent 3,720,96 & the possibility has been disclosed of replacing the cam controlling the operating position of the boring and extraction pin, such to produce rivets having different lengths, as well as provided with an internal bore having a variable length.

The replacement of said cam with other cams, both due to the above said need, and, e.g., for maintenance purposes, with a new carn, does not result very easy.

In fact, the cam is presently inserted on the relevant shaft, positioned in correspondence of a stop collar integral with the shaft, and is blocked by means of a sleeve which is axially movable along said shaft, between a position wherein said cam is blocked, and a position wherein said cam is disengaged.

The sleeve element is internally provided with a screw-threading which is engaged with a relevant threaded portion on the shaft, and once that it, by screwing down, has engaged a lip axially protruding from the same cam, which enters a complementary hollow, is blocked by a second nut, or safety nut.

Such a way of positioning, as stated in patent 3,720,968, is carried out by means of a proper tool, which, even if determines an optimum end arrangement of the concerned components, requires a rather long time for replacement, and a sureLy difficult access to the operating area, due to the present and closeness of other operative components of the press.

The purpose of the present invention is to provide a device which overcomes this difficulty in cam positioning and replacement, while simultaneously securing a perfect stability and a sure locking of the cam, once that said cam is positioned in its seat.

This, and still other purposes, according to the present invention, are achieved by providing a device for the rapid change of cams in a press for the production of solid rivets, partially bored rivets, tubular rivets, and the like, positioned on a revolving shaft, wherein at least one cam is mounted in an removable way on a complementary seat on said shaft, provided in correspondence of a stop collar integral with the shaft, wherein a sleeve element is provided, which can be axially shifted along said shaft between a first position wherein said cam is tightly locked, and a second position wherein said cam is disengaged, characterized in that said sleeve element is positioned, in such way as to be shiftable, on a bush, which is made integral with said shaft, and- wherein said seat for said cam is provided, with the sleeve element being positioned inside the interior of a lid element, such to be shiftable inside said lid element, in tightly sealing relationship with it, with said lid element being axially constrained to said shaft, inside said lid element a chamber being defined, which is connected, by means of radial ducts, and ring-shaped chambers, provided both on said sleeve element and on said bush, with at least one duct provided inside said shaft, and connectable to a source feeding a pressurized fluid, elastic means being furthermore provided, which interact between said lid element, and said sleeve element, such to maintain this latter resting in said first position.

A preferred, exemplifying and non-limitative, form of practicaL embodinent of the device according to the present invention, is now disclosed in order to render better understandable the essential characteristics of the same device. A detailed disclosure is made by referring to the hereto attached drawings, wherein: Figure 1 shows a partially sectional elevation view of a device according to the present invention, wherein a cam is installed, and Figure 2 shows sectional view according to path II-II of Figure 1, with the cam being shown exploded from its seat.

In a machine for the production of solid rivets, partially-bored rivets, tubular rivets, and the like, the couple of conical gear wheels 11 and 12 is driven to rotate, by means of motion transmitting devices (not .shown in the figures), and, consequently, a shaft 13 is driven to rotate, which drives a cam 15 for the reciprocating and predetermined drive of a component (not shown in the figures), i.e., of a rod, relatively to the stationary matrix, wherein the required machining of the rivets takes place.

Both said conical gear wheels 11 and 12 are keyed on respective revolving shafts 14 and 13, with the shaft 13, i.e., the shaft supporting the cam 15, being equipped with a device for the rapid change of the cam according to the present invention.

The shaft 13 is rotatably supported on bearings 16, and it blocks a bush 18 by means of an end-collar element 17. The bush 18 is provided with a radially protruding end portion 19 with a recessed seat 20, and the cam 15 or, better, a complementary internal opening 21 provided inside the cam 15, such to -render said cam removable, is positioned and fastened on said recessed seat 20 provided on said end portion 19.

The shaft 13 is provided, along a certain length thereof, with a screw threading 22, on which a complementarily screwed bore 23, axially provided on an end flange 24, inmeshes. A cylindrical hollow portions 25 axially protruding from one side of the same flange 24 is brought to engage the end of the bush 18, by resting against it. A further nut 26 acts as a counter-nut, blocking, relatively to the screw-threading 22 of the shaft 13, both the bush 18 and the end flange 24. An axial duct 27 is provided inside the shaft 13, starting from an end of said shaft, up to reach at least a radial duct 28 which faces a ring-shaped discharge channel, or hollow, 29, provided inside the bush 18.

Said ring-shaped discharge duct 29 acts as a chamber , and is in communication, through a set of radial ducts 30, provided inside the body of the bush 18, with a second ring-shaped discharge duct, or hollow, 31 provided on the outer surface of the bush 18.

A couple of lip seals 32, positioned inside relevant seats provided on the bush 18, secure the tight sealing relatively to the external environment, by operating on, in resting relationship with, the inner, cylindrical, hollow surface 33 of a sleeve element, which performs the function of cam-blocking flange, generally indicated by the reference numeral 34.

Said sleeve element 34, in fact, can be axially shifted on the outer surface of the bush 18, and on an end thereof a hollow 35 is provided, whose surface is flared, according to a conical shape,.in 36, towards said internal surface 33, such to interact, in a stable coupling relationship, with a lip 37, axially. and laterally protruding from the cam 15, with a complementary conical section.

The axial movement of the sleeve element 34 relatively to the bush 18 is secured by the presence of a tongue 38 integral with the bush 18, and sliding inside a surface axial hollow 39, provided on a portion of the inner surface 33.

Also inside the body of the sleeve element 34, a set of radial ducts 40 are provided, which connect the second ring-shaped discharge channel 31 with a variable -annular chamber 41, defined by a lid element 42, which is mounted above the sleeve element 34, and the same sleeve element 34. The chamber 41 is equipped with end lip seals 43, the one provided on the element 34, and the second being provided on the other element 42, or vice-versa.

Integral with said lid element 42, whose body has a shaped-bell shape, constrained is the end flange 24, by means of a set of fastening screws 44, wherein inside said end flange 24, at least a duct 45 is provided, which enables the air contained inside a further annular counter-chamber 46 defined between the end of the sleeve element 34, and the assembly formed by the lid cover 42 and the end flange 24, integral with each other, to vent to the external environment.

It should be furthermore observed that inside the body of the sleeve element 34, a circular set of countersunk bores 47, parallel to the axis of the shaft 13 and to the axis of the same sleeve element 34, are provided, inside which bores an equal number of springs 48 are located, which normally act such to keep the flared surface 36 of the sleeve element 34 and the lip 37 of the single cam 15 coupled with each other.

Of course, the load of the springs 48 shall be such as to secure a stable coupling, and the surface of the annular chamber 41 shall be such as to be able to develop a thrust capable of disengaging said coupling, by compressing the springs 48.

The stroke of the sleeve.element 34 must make it possible the lip 37 to get completely disengaged from the flared surface 36, allowing the cam 15 to be rapidly and simply removed.

The presence of the ring-like hollows 29 and 31 makes it possible, on the side, the unit to be properly assembled, with the possibility of variable configurations, on the shaft 13, such to anyway connect the duct 28, and the fluid to flow from said duct 28 towards the ducts 40 of said sleeve element 34 both in the first operative position and in the second operative position.

Preferably, the sleeve element 34 shows an end portion 50, which is enlarged, and sliding, under tight sealing relationship, inside a bell-shaped portion 51 of said lid element 42, so to realize the cylinder-piston portion of the device according to the present invention, having a larger thrust, such to be able to easily exceed the load of the springs 48.

Furthermore, in order to make it possible the axial duct 27 to be connected with the external source of pressurized air, at the end of the shaft 13 a freely rotatable connection element 4.9 is provided, such as not to disturb the revolution of the same shaft.

In fact, when one wants to remove, and change the cam 15, pressurized air is fed, through the connection element 49, to the axial duct 27. Such air, by sequentially flowing, through the radial duct 28, the ring-shaped discharge channel 29, the radial ducts 30, the second ring-like discharge channel 31, and from there, through the further radial ducts 40, enters the annular chamber 41.

The thrust inside said chamber 41, by exceeding the elastic thrust applied by the springs 48, causes the the sleeve element 34 to axially shift, rearwards, until the flared, conical surface 36 of said sleeve element 34 gets disegnaged from the lip 37 of the cam 15.

The cam 15 can thus be easily removed from its seat 20, and replaced by a new one. By discontinuing said compressed air supply from the duct 27, after carrying out such cam replacement, the thrust inside the chamber 41 is no longer present, and the springs 48, interacting between the end flange 24 and the sleeve element 34, bring this latter back to it position of engagement on the same cam.

By means of a device for the rapid change of the cams according to the present invention, said operation of cam change can-be therefore carried out without the aid of special tools, and, above all, also inside relatively narrow spaces, because only a free space slightly larger than the dimensions of the cam is necessary in order to remove said cam from its seat.

The blocking of the cam by means of the elastic thrust action performed by the springs is furthermore a greater guarantee--for a correct positioning, because it uniformly develops throughout the conical surface of the sleeve element, or cam-blocking flange.

Claims

a i m s

1. Device for the rapid change of cams in a press for the production of solid rivets,. partially bored rivets, tubular rivets, and the like, positioned on a revolving shaft, wherein at least one cam is mounted in a removable way on a complementary seat on said shaft, provided in correspondence of a stop collar integral with the shaft, wherein a sleeve.element is provided, which can be axially shifted along said shaft between a first position wherein said cam is tightly locked, and a second position wherein said cam is disengaged, characterized in that said sleeve element is positioned, in such way as to be shiftable, on a bush, which is made integral with said shaft, and wherein said seat for said cam is provided, with the sleeve element being positioned inside the interior of a lid element, such to be shiftable inside said lid element, in tightly sealing relationship. with it, with said lid element being axially constrained to said shaft, inside said lid element a chamber being defined, which is connected, by means of radial ducts, and ring-shaped channels provided both on said sleeve element and on said bush, with at least one duct provided inside said shaft, and connectable with a source feeding a pressurized fLuid, elastic means being furthermore provided, which interact between said lid element, and said sleeve element, such to maintain this latter resting in said first position.

2. Device according to claim 1, characterized in that said lid element is axially constrained onto a screw-threaded portion of said shaft, by means of an axial screwed bore thereof, and by means of a nut element, also screwed down on said screw-threaded portion, acting as a counter-nut.

3. Device according to claim 2, characterized in that from said lid element, a cylindrical, hollow portion axially extends towards said bush, such to constitute a stop for it, and define said chamber.

4. Device according to claim 1, characterized in that said cam and said sleeve element are equipped with conical surfaces for mutual axial engagement.

5. Device according to claim 1, characterized in that at least said one duct provided inside said shaft comprises an essentially axial portion, which can be connected wi.th said source for supply of pressurized fluid, and with a radial portion connected with said radial ducts and said ring-shaped channels.

6. Device according to claim 1, characterized in that on said bush, on its outer surface facing said .sleeve element, a ring-shaped channel is provided in correspondence of said radial ducts, such to secure the flow of said fluid in both said first position and said second position of said sleeve element.

7. Device according to claim 1, characterized in that said elastic means are a set of springs located parallelly to said revolving shaft.

8. Device according to claim 1, characterized in that said sleeve element is provided, inside said chamber, with an extended portion complementary to a portion of said lid element.

9. Device for the rapid change of cams in a press, said device being substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.