EP0526380A1

EP0526380A1 - Step-by-step timer switch activation system for program control devices

Info

Publication number: EP0526380A1
Application number: EP92500098A
Authority: EP
Inventors: José Cruz Leibar Guridi; Michel Chauvigne
Original assignee: Fagor Electrodomesticos SCL
Current assignee: Fagor Electrodomesticos SCL
Priority date: 1991-08-02
Filing date: 1992-07-28
Publication date: 1993-02-03
Anticipated expiration: 2012-07-28
Also published as: EP0526380B1; ES2034919A6; DE69211440D1

Abstract

The system incorporates advantages that comprise providing the positioning ratchet (23) with a shaft (25) about which an elevating lever (12) can swing which can take up an active and an inactive position such that when the cogs (10) on the block of program cams (15) elevate the ratchet (23), the elevating lever (12) takes up the active position and is thereupon returned to its inactive position when its free end (32) is moved by a rotatory boss (31) integral with the excentric cam (1), dragging with it in this latter movement the anti-return ratchet (15), causing the latter to draw away from the holding cogs (34) on the timer cam (6) at a time when the catch (4) on the driving pawl (3) is also drawn away from the same, allowing the timer cam to be reset.

Description

OBJECT OF THE INVENTION

The present invention relates to a number of improvements to the step-by-step timer switch activation system for program control devices subject of European Patent application 92500004.4 dated 14th January 1992, such improvements being aimed at eliminating possible functional anomalies in the said system.

BACKGROUND OF THE INVENTION

Step-by-step timer switch activation systems for program control devices exist, for instance as in the same applicants' European Patent application 92500004.4 dated 14th January 1992, such system comprising two subsystems that can act jointly or separately, with one of which subsystems time intervals of a duration equivalent to the turning period of the fast cam or fractions thereof can be obtained, and with the second of which any of the time intervals of the first subsystem can be multiplied by two preset factors.
The risk of the system set forth in the patent lies in that if when the control device shaft is turned by hand to select a working program or to eliminate a part thereof the drum of program cams is incorrectly positioned between two stable positions, it might stay there permanently, unable to continue its forward movement, whereupon the machine governed by the control device will run the working phase (heating, centrifuging and so forth) corresponding to such position endlessly, until the user becomes aware of this.

DESCRIPTION OF THE INVENTION

Though many things can lead to an incorrect positioning of the drum of program cams, the device subject of this addition is designed so that even if such event does come about the drum of program cams shall not be permanently stopped in the said position, allowing the driving mechanisms to act upon the same and move it towards a stable position so that it may thereafter resume its normal operation.
A second advantage of the system lies in that though its actuation is linked to the movement of the positioning ratchet by cogs integral with the drum of program cams, the strength with which the same impinges upon the latter is only slight, thereby facilitating the obtention of low turning torques of the said drum of program cams if so desired. The above without impairing any of the benefits envisaged in the system set down in the main patent.
The system is designed such that when the drum of program cams moves one step forward by hand or automatically, the cogs integral with the latter usually and conventionally cause a positioning ratchet to rise and fall. This movement in turn causes an elevating swivel lever to be reset, the free end of which lever is subsequently driven by a transmission element driving the same from time to time, the period being under or equal to the period of duration of the shortest timing, so that moving the lever counter the reset travel direction causes the ratchet holding the timer wheel to draw away at a time when the driving pawl is also drawn away therefrom, whereupon the same is free to be reset. The device shall then be able to work again, according to the parameters corresponding to the angular position of the drum of program cams.
In addition to what the main patent proposes, a second possibility has been provided to drive the timer wheel, according to which when the selection lever follower is on a selection cam profile of narrowest or medium radius, the resetting abutments define a partially advanced position for the timer wheel, the first counting cog thereof lying within reach of the respective catch of the driving pawl.

DESCRIPTION OF THE DRAWINGS

In order to provide a fuller description and contribute to the complete understanding of the characteristics of this invention, a set of drawings is attached to the specification which, while purely illustrative and not fully comprehensive, shows the following:
Figure 1. - Is the system disposed for basic timings or fractions thereof.
Figure 2.- Is the system just as it moves to a multi-timing position.
Figure 3.- Is the timer cam and the advancing pawl in a multi-timing process.
Figure 4.- Shows the system in an intermediate step position at the end of a multi-timing period.
Figure 5.- Is the reset system of the timer cam in a reset position.
Figure 6.- Is the system with the timer cam released to be reset.

PREFERRED EMBODIMENT OF THE INVENTION

In light of this figure it is clear that the excentric cam (1), upon turning continuously about its centre (2) provides the driving pawl (3) with a reciprocating motion such that its catch (4) can cause either the block of program cams (5) or the timer cam (6) to advance step by step.
In the case of figure 1, since the selection lever (8) follower (7) is borne by a cam profile (9) of widest radius, the timer cam (6) lies beyond reach of the pawl (3) catch (4) and can therefore only act upon the cogs (10) integral with the drum of program cams (5). On the other hand, the timer cam (6) reset system is at rest since the boss (11) on the elevating lever (12), which is at its position furthest from the timer cam (6) tunring centre (13), lies behind the end of the anti-return ratchet (15).
When the system moves to a multi-timing position, figure 2, the selection lever follower (7) is placed at a level (16) or (17) other than that (9) of widest radius, causing the selection lever (8) to swing about its turning centre (18), overcoming the force of the spring (19) that opposes such movement. When the follower (7) moves to either of the two levels other than (9) it also displaces the abutment (38) integral with the selection lever (8), which in turn impinges upon a profile (21) on the timer cam to move the latter to an angular position that is slightly more advanced than that corresponding to the position with no multi-timing of figure 1. When the block of program cams (5) moves one step forward, the boss (11) on the elevating lever (12) takes up, as shall be explained hereinafter, its active position, before the end (14) of the anti-return ratchet (15) to move soon after, as shall also be explained hereinafter, to the position shown in figure 1. The movement of the boss (11) on the elevating lever from the position of figure 2 to that of figure 1 is aimed at resetting the timer cam (6) but as in this case it is already in its starting position or at rest, it bears no effect upon the same.
When the driving pawl moves back, figure 3, it meets the somewhat advanced timer cam, as explained before, and therefore the driving pawl (3) catch (4) meets the first cog (20) on the timer cam that prevents the catch (4) from reaching the cogs (10) on the block of program cams (5), which is when the timing stroke of the timer cam begins, operating hereafter as described in the main patent saving as regards its release to be reset and its actuation.
When a deeper space (21) in the counting cogs (22) on the timer cam (6) comes within reach of the driving pawl (3) catch (4), figure 4, the catch (4) can penetrate the same, in which event it reaches the cogs (10) on the block of program cams. Figure 4 shows the system in an intermediate step position, i.e., between two stable positions, where the positioning ratchet (23) can be seen located upon the tip of the cogs (10) on the block of program cams. The elevation of the positioning ratchet (23) from the bottom to the tip of the cogs (10) on the block of program cams causes the elevating lever (12), which is disposed to swing about a shaft (25) integral with the positioning ratchet (23), to move in the direction of the arrow (24). This displacement causes the boss (11) on the elevating lever (12) to be drawn away from the end (14) of the anti-return ratchet, allowing the elevating lever to move from the position of figure 1 to that of figure 2, by means of a spring (26) that urges the same towards the latter, the system then moving forthwith to the position shown in figure 5.
Figure 5 shows how, after the block of program cams (5) moves one step forward, the catch (4) on the driving pawl shall have been drawn away from the cogs that it drives, such withdrawal being caused jointly by the rotation of the excentric (1) in the direction of the arrow and the spigot (27) integral with the bearing plate (28) driving an internal profile (29) of the driving pawl (3), overcoming the force of the spring (30) that tends to draw the catch towards the said cogs.
If rotation of the excentric (1) continues, a projection (31) therefrom pushes the end (32) of the elevating lever towards the outside and the movement of the boss (11) on the elevating lever is transmitted to the end (14) of the anti-return ratchet, which turns drawing its catch (33) away from the cogs (34) holding the timer cam (6), which is free to be reset, given that the catch (4) on the driving pawl has also been drawn away. Resetting comes about by action of the extension spring (35) that causes the timer cam to turn until the surface (36) or (37), depending upon whether the next step is multi-timing or otherwise, abuts against the abutment (38) on the selection lever (8). Finally, the boss (11) on the elevating lever overruns the end (14) of the anti-return pawl, so that both take up the position of figure 1.
We feel that the device has now been sufficiently described for any expert in the art to have grasped the full scope of the invention and the advantages it offers.
The materials, shape, size and layout of the elements may be altered provided that this entails no modification of the essential features of the invention.
The terms used to describe the invention herein should be taken to have a broad rather than a restrictive meaning.

Claims

1.- Step-by-step timer switch activation system for program control devices of the kind comprising at least a time interval multiplication system based upon a timer cam or element driven step by step by a catch with a reciprocating movement and having the appropriate driving, holding and resetting means, characterised in that the holding and resetting system incorporates a positioning ratchet (23) at whose free end is a shaft (25) integral therewith; an elevating lever (12), one of whose ends is fitted to swing about the shaft (25) on the free end of the ratchet, which is moreover provided with a boss (11) located between the said end and the free end thereof; an excentric cam (1) with a projection (31) which upon turning moves the free end of the elevating lever causing the same to swing towards its position furthest from the system centre; an anti-return ratchet (15) disposed to swing about a shaft integral with the mechanisms bearing plate, provided with a holding catch (33) at one of its ends, the other end (14) being formed so as to be dragged by the boss (11) on the elevating lever upon moving towards its position furthest from the system centre; a driving pawl (3) with an internal profile (29) working with a spigot (27) integral with the mechanisms bearing plate in order for the pawl to rise when moving back; resilient means urging the positioning ratchet (23) towards the cogs on the cam, the elevating lever (12) towards its position closest to the system centre, the anti-return ratchet (15) towards its position in contact with the respective cogs on the timer cam (34), the latter to its starting position and the driving pawl (3) towards the relevant cogs.

2.- Step-by-step timer switch activation system for program control devices, as in claim 1, characterised in that the elevating lever follows the upward and downward movement of the positioning ratchet (23) each time the block of program cams (5) turns, such that when the ratchet is at the highest position on the block cogs (10), the boss (11) on the elevating lever positions itself above the end (14) of the anti-return ratchet whereupon the elevating lever, by action of its resilient means, positions itself closest to the system centre.

3.- Step-by-step timer switch activation system for program control devices, as in the above claims, characterised in that before the elevating lever ends its stroke away from the system centre, the boss (11) positions itself at the highest point on the end (14) of the anti-return ratchet, whereupon the same can, by action of its resilient means, contact the relevant cogs (34) on the timer cam.

4.- Step-by-step timer switch activation system for program control devices, as in claim 1, characterised in that when the follower (7) on the selection lever is upon the selection cam profile of widest radius (9) the timer cam takes up a first rest position defined by the abutment (38) on the selection lever and the ramp (37) on the timer cam where its cogs (20) lie beyond reach of the catch (4) on the driving pawl, whereas when the follower (7) is on either of the two other levels (16) or (17), the abutment (38) on the selection lever defines, with the assistance of the ramp (36) on the timer cam, a second rest position of the timer cam, somewhat advanced, and within reach of the catch (4).