GB2058269A

GB2058269A - Safety device for securing protection covers of machines

Info

Publication number: GB2058269A
Application number: GB8022718A
Authority: GB
Original assignee: Truetzschler GmbH and Co KG
Current assignee: Truetzschler GmbH and Co KG
Priority date: 1979-07-14
Filing date: 1980-07-11
Publication date: 1981-04-08
Also published as: CH647273A5; JPS5694093A; BR8004332A; FR2461883A1; IT1131924B; GB2058269B; DE2928507A1; FR2461883B1; DE2928507C2; ES493365A0; ES8105460A1; IT8023311A0

Abstract

A device for locking an openable cover 14 of a textile machine having movable parts 3 comprises an electric circuit 5 in which are connected a power source 6, a manually operable switch 7, an operating unit 8 and a monitoring means 2, 4, which may comprise a tachogenerator 2 and a relay 4, controlled by the movement of the movable machine part 3. The operating unit 8 shown includes a hooked locking lever 11 movable by an electromagnet core 9 between a cover locking position and a cover unlocking position according to whether power is supplied to the operating unit. The operating unit 8 can only operate the lock when both the part 3 has stopped rotating and the switch 7 has been manually closed to complete the circuit from the power source 6. The operating unit may comprise toggle linkage pneumatically operated and worm gearing motor operated. <IMAGE>

Description

SPECIFICATION Device for securing protective covers of machines This invention relates to a device for securing the openable parts of protective covers in machines having movable and/or self-moving parts and the like, for example rotating shafts, cylinders and the like, in particular a locking device for the openable protective cover parts in textile machines, such as carding machines and the like, using a stoppage monitor that monitors electrically the movement of the movable machine parts, a manually operable switch and an operating unit controlled by the stoppage monitor and influencing the locking and unlocking.

In a device disclosed in DE-GM 76 07 709 the core of an electromagnet is tripped by a stoppage monitor (not described in detail). As a result of the displacement of the core, a switch (adjusting unit 3) is released. The switch can now be pressed in by hand whereby an angle lever is simultaneously operated. In this manner the locking of an operating unit (adjusting unit 4) is suspended, the projecting portion of which unit is used as a handle for moving a push rod. The locking parts connected to the push rod are thereby moved out of the path of the hook connected to the protective cover so that the protective cover is unlocked and can be opened.

The disadvantage of this device is that two operating members, namely the adjusting units 3 and 4, must be operated by hand. A further disadvantage results from the fact that the adjusting units 3 and 4 are linked to one another mechanically so. that it is possible only in a structurally complicated manner to unlock several safety devices by a central switch that are arranged at a great distance from one another or around corners.

According to the invention there is provided a device for the openable parts of protective covers in machines having movable and/or self-moving parts and the like, for example rotating shafts, cylinders and the like, in particular a locking device for the openable protective cover parts in textile machines such as carding machines, bale openers, step cleaners, fine openers and the like, using a stoppage monitor that monitors electrically the movement of the movable machine parts, a manually operable switch and an operating unit controlled by the stoppage monitor and influencing the locking and unlocking, characterized in that the stoppage monitor is connected to an electric circuit, the electric circuit has a voltage source, a switch and an operating unit and, by operating the switch, the operating unit operates the locking and unlocking.

The operating unit is arranged in an electric circuit. The operating unit is not activated by the switch until, for example, a tachogenerator no longer supplies voltage and the electric circuit is closed via, for example, a voltage relay. The electric switch is then operated by hand. The operating unit in the electric circuit is thereby displaced and acts automatically on the mechanically adjustable locking and unlocking device. In this manner, it is possible to unlock the protective cover merely by operating the switch by hand.A particular advantage is that the operating unit, being spatially separate from the switch, can be arranged on unlocking mechanisms that are arranged at a great distance from one another or around corners; the switch is connected in a simple manner and without difficulty to the operating unit or several operating units by electrical lines in a structurally simple manner. At the same time there is no need to use expensive braking devices that can ensure the immediate stoppage of machine parts when disconnecting by means of safety or emergency switches.

As the component to be monitored rotates, the stoppage monitor generates a voltage; when the component stops, the stoppage monitor no longer generates voltage. The stoppage monitor is preferably a tachogenerator that must be fitted on the rotating or moved component, for example the rotating roll of a machine, that has the longest after-run. This applies to the protection of both an individual machine and a complete machine group or machine installation. It is also possible to provide each individual machine with a tachogenerator.

The stoppage monitor is advantageously connected to the electric circuit via a voltage relay, for example a voltage-measuring relay. The relay is controlled by the tachogenerator and influences the electric circuit. The tachogenerator can also be advantageously linked by an electronic network to the electric circuit. The electronic network may introduce a time delay between stopping of the tachogenerator and closing of the circuit.

Advantageously, the operating unit is controlled electromagnetically and produces a mechanical movement that operates the unlocking mechanism. It is also possible to use as the operating unit a hydraulic or pneumatic operating cylinder that can be switched via solenoid valves.

Furthermore, it may be advantageous for the operating unit to be an electric motor that opens one or more catches, for example via a spindle.

This operation by means of an electric motor may be used for locking a series of covers of the same or different machines.

If there is no voltage from the machine supply for activating the operating unit, for example in the case of the failure of the mains voltage, then by automatic switching, the operating unit, for example the magnetic coil of the electromagnet, can be supplied from a power store, for example a battery. It is also possible to use a separate power supply as an emergency supply. In this manner it is possible to unlock the doors even if no voltage can be taken from the mains.

According to a preferred embodiment, a limit switch is associated with the cover, door or the like, which switch is connected to the electrical drive of the rotatable component. This limit switch monitors the stoppage of the machine and is controlled by the unlocking and locking device.

This limit switch is switched by the opening of the cover, door or the like and prevents the possibility of connecting the rotating component unintentionally or when such action is unauthorised.

Advantageously, a signalling apparatus indicates the opening of the cover, door or the like.

An optical and/or acoustic signalling apparatus is preferably used for this purpose. It is thereby possible to indicate centrally the unlocking operation. It is also possible to indicate the releasing of the lock individually at the central control. The voltage of the tachogenerator is preferably monitored by monitoring the stoppage of a motor driving a rotating component, for example the drive motor of the cylinder of a carding machine. If the tachogenerator stops, the electric circuit in which the operating unit is arranged can be closed only via a slow-acting relay.

It is in principle possible to protect an individual machine with the device according to the invention. It is also possible to protect groups of machines or an entire installation with the device according to the invention. Finally, the device permits individual machines within a protected group of machines to be protected. Any selected fast-running rollers can, via tachogenerators, be allotted to a locking chain and monitored. The central protection of an entire machine group or installation permits structural simplification and, possibly, savings. The locking and unlocking device must be attached to each protective cover, door, flap or the like to be secured.In so far as only a single locking switch is provided, for one machine or for an entire installation, this switch is advantageously arranged in a central position, for example within a central switchboard plant.

According to a preferred embodiment for the central protection of an entire machine group or installation, voltage is taken as far as the individual doors, covers or the like by the centrally fitted press switch via a timing element. a further press switch being connected upstream of each electromagnet for the individual doors, with which switch only the electromagnet of the particular door to be opened can be energised. This type of locking has the advantage that the amount of unlocking power necessary for the electromagnets corresponds to the number of doors to be opened simultaneously rather than the total number of doors.

By way of example certain illustrative embodiments of the invention will be described with reference to the accompanying drawings, of which: Figure 1 shows a carding machine including a device embodying the invention; Figures 2a and 2b show part of the device of Figure 1, Figure 3 shows an alternative form for the part of the device shown in Figures 2a and 2b, Figures 4a and 4b show an alternative form for part of the device in which a pneumatic cylinder is used as the operating unit, Figure 5 shows an alternative form for part of the device in which an electric motor having a spindle is used as the operating unit and Figure 6 shows the protection of an entire machine group.

The device of the embodiment of Figure 1 is associated with a carding machine 1 and has a tachogenerator 2 as a stoppage monitor that is associated with the cylinder 3 or the carding machine 1. The tachogenerator 2 is connected via a voltage measuring relay 4 to an electric circuit that has a voltage source 6, a press switch 7 and an electromagnet 8. Referring to Figure 2a, as well as Figure 1, the core 9 of the electromagnet 8 (Figure 2a), one end 9a of which rests on a fixed support, is in contact via its other end 9b with the end 11 a of a rotatable double lever 11 (mechanically operable catch). The other end 11 b of the double lever 11 has a recess 12 in which engages the angled tongue 1 3a of a hook 13 that is firmly attached to a protective cover 14, for example the discharge flap of a carding machine 1.In addition, a limit switch 1 5 is associated with the inside of the protective cover 14, which switch is in electrical connection with the drive (not shown) of the cylinders 3 so that opening of the switch disconnects the drive for the cylinder 3.

In operation, the tachogenerator 2 generates a voltage for as long as the cylinder 3 rotates. When the cylinder 3 stops, the voltage relay 4 is operated which closes the electric circuit 5 at one point. By operating the press switch 7 by hand by means of which the electric circuit 5 is closed completely, the core 9 of the electromagnet 8 is actuated. The core 9 moves upwards against the force of gravity and presses on the end 11 a of the double lever 11. The end 11 a is thereby lifted and as a result of the rotation of the double lever 11 about the pivot point 11 C the end 11 b having the recess 12 is lowered.The tongue 1 3a of the hook 1 3 is now free so that the protective cover 14 can be opened (Figure 2h). The limit switch 1 5 is switched over by the opening of the protective cover 14 and prevents the possibility of connecting the cylinder 3 to its power supply.

Figure 3 shows the operating unit two electromagnets 8 the cores 9 of which each engage behind a hook or eye 13 that is firmly connected to the door 14. When the electromagnet 8 is energised the core 9 is retracted into the electromagnet 8 so that the hook 13 is freed. The door 14 can then be opened.

According to Figures 4a and 4b, the operating unit is formed by a pneumatic cylinder 95 that is switched by solenoid valves (not shown). The cylinder rod 1 6 is connected via toggle links 17, 18 and joints 21,22 and 23 to two toggle links 19 and 20 so they engage in the openings 24 and 26 of two eyes 25 and 27 that are connected firmly to the doors. Figure 4a shows the device in the open state while Figure 4b shows the device in the closed state.

According to Figure 5, a motor 28 is provided that drives, via a worm wheel 29, a spindle 30 (worm), one end of which engages in the opening 31 of a hook (or eye) 32 that is secured to the door 14.

According to Figure 6, a group of several machines is protected centrally. A step cleaner 35 is connected downstream of two bale openers 33, 34, which step clean is connected to two fine openers 36, 37 that feed a number of carding machines 38 by means of flock feeding installations. Associated with the carding beater (not shown) of the fine opener 37 is a tachogenerator 2 that is connected electrically to a centrally arranged control panel 39 that is equipped, inter alia, with the press switch of the electric circuit. Each door to be secured for example door 14 at the bale opener 23, is associated with an operating unit (cf. Figures 1 to 4) that is connected via electrical lines to the control panel 39. The member of the machine group having the longest after-run, the carding beater, is provided with the tachogenerator 2.

Only a single press switch is provided for the entire group, which switch is arranged centrally in the control panel 39. On the operation of the press switch all electromagnets used for locking are energised via a timing element 40 and remain energised until the expiry of the time set. This time is so set that the operator can reach and open the furthest door. All the doors are preferably also closed by a magnetic clamp or the like.

Claims

1. A device for locking an operable cover of a machine having movable parts, the device including an electric circuit in which are connected a power source, a switch, an operating unit and a monitoring means controlled by the movement of a movable machine part, the operating unit including locking means movable between a cover locking position and a cover unlocking position, the locking means being in one position when the operating unit is disconnected from the power source and in the other position when the operating unit is connected to the power source.

2. A device according to claim 1 in which the monitoring means includes a tachogenerator.

3. A device according to claim 1 or 2 in which the monitoring means includes a voltage relay connected in the electric circuit.

4. A device according to claim 1 or 2, in which the monitoring means is connected to the electric circuit via an electronic network.

5. A device according to any preceding claim in which the switch is a push-button switch.

6. A device according to any preceding claim in which the operating unit is electromagnetically controlled and produces a mechanical movement.

7. A device according to any of claims 1 to 5 in which the operating unit is a hydraulic or pneumatic operating cylinder that can be switched via solenoid valves.

8. A device according to any of claims 1 to 5 in which the operating unit is an electric motor that opens one or more catches, for example via a spindle.

9. A device according to any preceding claim in which the movable part of the operating unit is in direct engagement with a part secured to the protective cover.

10. A device according to any preceding claim in which the operating unit is capable of displacing one end of a rotatable lever and in so doing holding member for the protective cover can be released from the other end of the double lever.

11. A device according to any preceding claim in which the voltage of the tachogenerator is monitored by monitoring the stoppage of a motor driving a movable part and when the tachogenerator stops, the electric circuit is closed only via a slow-acting relay.

12. A device according to any preceding claim in which the voltage source is a battery.

13. A device according to any preceding claim in which a limit switch is associated with the protective cover, which switch is connected to an electrical drive of the movable part.

14. A device according to any preceding claim in which a signalling apparatus indicates the opening of the protective cover.

1 5. A device according to any preceding claim in which an optical and/or acoustic signalling apparatus is used.

16. A device according to any preceding claim in which protective covers on several machines of an installation are secured centrally.

17. A device for locking an operable cover of a machine having movable parts the device being substantially as herein described with reference to and as illustrated by Figures 1, 2a and 2b or by Figures 1 and 3 or by Figures 1,4a and 4b or by Figures 1 and 5, of the accompanying drawings.

18. A textile machine including a device as claimed in any preceding claim.

19. A textile installation substantially as herein described with reference to and as illustrated by Figure 6 of the accompanying drawings.