WO2004071165A1

WO2004071165A1 - Safety device for a working tool

Info

Publication number: WO2004071165A1
Application number: PCT/SE2003/000264
Authority: WO
Inventors: Per-Olof Zakrisson
Original assignee: Aktiebolaget Electrolux
Priority date: 2003-02-17
Filing date: 2003-02-17
Publication date: 2004-08-26
Also published as: AU2003211792A1

Abstract

The present invention relates to a safety device in working implements (1) comprising at least one handling object (25). Said handling object (25) may be covered by a lid (7), which is actively connected to an out of service-taking means (6), whereby said handling object (25) is essentially inaccessible until said out of service-taking means (6) has made the working implement inoperative. The present invention also describes a working implement (1) comprising a safety device of this kind.

Description

Safety Device for a Working Tool

TECHNICAL FIELD

The present invention relates to a safety device in working implements of the kind comprising at least one handling object. The present invention likewise refers to a working implement.

TECHNICAL FIELD OF INVENTION In order to ensure that nobody is injured when using consumer products or other types of working implements that are handled by people and that comprise sharp and/or other moving parts constituting a potential hazard to the user, extreme importance must be given to making them so easy to handle that the possibility of wrong-handling is practically null. Consumer-friendliness jointly with systems designed to prevent access to dangerous components often even are of such importance that they are subjected to legal restrictions. The type of consumer products and working implements that are intended particularly for use out of doors are subjected to additional requirements as regards vulnerable details, and for example control and fuse panels must be protected against the effects of weather and wind and against damage to the exterior, such as scratching. Also the risk that settings are unintentionally altered, for example as a consequence of contact with the environment during use of the working implement, should be avoided.

At the same time, from the user's point of view it is important that the controls and setting means are easily accessible and positioned within easy reach of the user, for example on the top face of the product in the case of ground-travelling working implements. These problems apply particularly to working implements of the kind that in some aspect are self-propelling and for that reason are not supervised to the same extent as conventionally. One example of a working implements of this kind are today's not only self-propelling but also automatic lawn mowers. Such lawn mowers are placed on the lawn to be mowed, and a control loop is deposited around the extreme border of the area concerned. The mower is then started and as a rule it runs across the lawn in random fashion. The mower is either battery-operated, in which case the battery is recharged automatically in a recharge station, or it is operated by solar energy, usually by means of an intermediary storage battery. Consequently, the lawn mower may perform its work entirely without interference from the user. For this reason, it is important that children or pets are not intentionally or unintentionally exposed to injury hazards when from curiosity they touch or fiddle with the machine exterior or interior.

While safety is of vital importance, the design aspect should not either however, be allowed to increase the load on the working implement, for instance particularly not in the form of heavy weight. Heavy weights would in turn entail higher energy costs, and in the end, shorter implement working range.

SUMMARY OF THE INVENTION

The object of the present invention is to solve, at least partly, the problems outlined above from which working implements suffer. These and other objects are achieved at least partly by imparting to a safety device of the kind defined in the introduction the characterising features appearing from claims 1 and 25. Preferred embodiments of the safety device appear from the claims that are dependent on claims 1 and 25.

The provision on a working implement of a safety device possessing these characteristics minimises the risk of personal injuries, since the safety device makes access to for instance a working-implement control panel more difficult during operation. While the safety device is in use it is impossible, during normal use, to reach e.g. buttons or levers controlling the working implement and/or the operational process thereof without the stop button being first activated, which interrupts the operational process of the working implement. By operational process in the sense used with respect to the patent should be understood not only the propulsion of the entire working implement but also the operation of the vital process of the working implement, such as the operation of the cutting blades in the lawn mower cutting unit. In this context it should also be mentioned that additional handling objects may exist in the working implement that are not affected by the safety device in accordance with the present invention but in this case such other handling objects are not of a nature that affects the operational process of the working implement.

As appears from claim 4, an additional embodiment of the invention makes it impossible to manipulate a handling object out of carelessness and to start the operational process of the working implement unless the lid is closed after the handling object has been handled. Not until the lid is closed can the operational process of the working implement start and the handling object of the working implement thus becomes practically inaccessible until such a time that the means serving to make the working implement inoperable, has fulfilled its function.

In addition, the fact that the lid necessarily must be closed in order to allow normal use after manipulation of the handling object also means that during operation the handling object runs no risk of being affected by external conditions, particularly in the case of the additional embodiment of the invention, according to which for reasons of user accessibility the handling object is located on the upper face of the working implement, such external conditions being e.g. scratching from dependent twigs or precipitation that may cause damage to the working implement, in addition to which such dependent twigs are prevented from affecting the set values of the working implement, randomly or without the user's wish. The same problems could of course arise in a safety device that assumes a more vertical position, in which case also other details may be a cause of damage.

In accordance with the embodiment of the invention when colours are used as distinguishing features between the working implement and the out of service-taking means, this use is adopted in order to make it easy for the user to understand the distinction and how to use the different means.

BRIEF DESCRIPTION OF DRAWINGS The invention will be described in the following in more detail with reference to the accompanying drawings, which for exemplifying purposes show presently particularly preferred embodiments of the present invention. In the drawings: Fig 1 is a perspective view of an automatic self-propelling lawn mower fitted with a safety device in accordance with the present invention.

Fig 2 is an exploded view of the body and the safety device in accordance with the invention.

Figs 3a-3d show in a view from above and in a perspective view, respectively, the lawn mower and the safety device in accordance with the present invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENT

Fig 1 shows an automatically self-propelling lawn mower 1, which is designed to automatically mow the grass on an area delimited by a loop that is arranged, at a lower battery level, to likewise automatically find and dock to a recharging station (not shown) and to thereafter continue the mowing operation. For this purpose, the lawn mower 1 is fitted at its front edge with a recharging device 5 arranged to find the recharging station and through the agency of the mower 1 itself be inserted into a corresponding part of the recharging station. Batteries, not shown, drive two wheels 2, which are located at the rear part of the mower 1 and which also control the direction of movement of the mower 1. In the front part of the mower 1, underneath the body 9, two small light-weight wheels, not shown, are provided, the only function of which is to support the mower 1 and the cutter unit thereof including a set of cutting blades.

The cutter unit and the set of cutting blades are located below the part of the mower 1 that is covered by a lid 3, which may be opened by means of a catch 4. The catch 4 is released when pushed forwards in the direction of travel of the mower 1 , whereupon the catch exposes the path of movement upwards of the lid 3, a spring, which is compressed in the locked position, urging the lid 3 slightly vertically upwards to make the task easier for the user. The lid 3 is turned upwards about its straight rear edge, as seen in the direction of travel of the mower 1, at which edge a hinge is provided. At the rear edge, the lid 3 is formed with a recess, in which a large, red-coloured stop button 6 is received. Upon depression of the stop button 6 the travelling forwards of the mower 1 is interrupted and the cutter unit including the cutting blades and blade-supporting disk are braked by electric means or in some other way ensuring that the unit stops and comes to a standstill almost immediately or in any case within two seconds.

On the stop button 6 the word STOP is shown in order to give the user easy understanding of the purpose of the button. Closely by the stop button 6, rearwards as seen in the direction of travel of the mower 1, a predominantly transparent sliding shutter 7 is positioned, its purpose being to protect the control panel 25 underneath (see Fig 3b). The sliding shutter 7 is interconnected with the stop button 6 via a lock mechanism to be described further on, the interconnection between these two means being such that it allows the sliding shutter 7 to be opened only when the stop button 6 is depressed. The control panel 25 controls the function or operational process of the mower 1, its travel forwards as well as the rotation of the cutter unit. The sliding shutter 7 opens as the stop button 6 is being depressed and closes when it is being pushed back to its closed position by means of a shutter handle 8, during which movement the stop button 6 "shoots" up to its vertically upper position. Because the mower 1 moves around the grass surface completely automatically it is important that its operational process is interrupted before other operations are initiated. In accordance with the teachings of the invention this is achieved because the only way to make the control panel accessible is to open the sliding shutter 7 by depression of the stop button 6, an action that first stops and brakes the mower 1.

Fig 2 shows more clearly the design of the various detail components of the mower 1. At the bottom of this figure is shown a back 19 intended to be attached to the rest of the body 9. Vertically upwards from the back 19 two guide ridges 11 extend in parallel with the direction of travel of the mower 1 and in inter-parallel relationship. Between said guide ridges 11 may be fitted rails 10, which are attached to the sliding shutter 7 and thus the extension of said rails matches that of said guide ridges 11. The guide ridges 11 serve to keep the rails 10 in position and ensure the engagement of tenons 12 in fixation means 13 in a locking device (tenons 1 and fixation means 13 will be described further on). The body 9 is also formed with guide ridges that assist in guiding the sliding shutter

7 as the latter is being pushed in the direction of travel of the machine. The length of the rails 10 approximately equals twice the length of the guide ridges 11, whereby they are able to push away the sliding shutter 7 completely and expose the control panel underneath and to maintain its function of guiding the sliding shutter 7 in the direction of travel. A vertically upstanding tenon 12 is arranged at the front edge of each rail 10. The edges of the tenon 12 are slightly rounded and its lateral faces extend in parallel vertically upwards. The rails 10 are made integrally with the sliding shutter 7 and are positioned one on either side of the sliding shutter 7.

In its closed position, the sliding shutter 7 fits into a recess 20 formed in the body 9 and it may be pushed rearwards relative to the direction of travel of the mower 1 along the guide ridges 11. In this open position, the sliding shutter 7 will be located below the neighbouring part of the body 9. In this open position the sliding shutter 7 may move freely between its maximum open position, wherein only the push handle 8 projects from the recess 20 formed on the body 9, and the position, wherein the tenons 12 abut against a locking device (to be described further on) without assuming its locking position. In this open position, the sliding shutter 7 does not affect the mower 1. The sliding shutter need not be transparent.

The stop button 6 may assume one of the following two positions, viz. the operational position and the stop position. In its operational position, the stop button 6 assumes its upper position and by means of the locking device referred to above it locks the sliding shutter 7 in the closed position of the latter. In this position, a switch 17 energising the operational process of the mower 1 closes the circuit, and consequently the mower could have been operational, had the control panel been set for this activity. The stop button 6 is kept in its upper position by two springs 16 in contact with the lower face of the stop button 6, one on each short side of the button, and so as to act against the body 9.

Upon depression of the stop button 6, against the action of springs 16, the above- mentioned locking device is released and the sliding shutter 7 opens while at the same time the switch 17 opens the circuit and any on-going operational process of the mower 1 is interrupted. The locking device thereafter maintains the stop button 6 in this lower stop position. The stop button 6 resumes its operational position when the sliding shutter 7 is pushed forwards in the direction of travel of the mower 1, whereby the locking device is released, freeing the stop button 6, which the springs 16 push upwards so that the button again assumes its upper position. When this happens, the switch 17 also closes the circuit.

The switch 17 is a contact breaker, which is positioned at the front edge of the stop button 6 (the edge turned in the direction of travel of the mower 1), which is securely mounted on a support 18 attached to the body 9. The switch 17 closes the circuit in the operational position of the stop button and opens it in the stop position as it is securely mounted on a support 18, which in turn forms part of the body 9 centrally at the front edge of the stop button 6. Positioned oppositely the contact breaker 17 on the support 18 a breaker edge 21 is arranged on the stop button 6, said edge 21 passively being brought along in the movements of the stop button 6. The edge 21 extends forwards in the direction of travel of the mower 1 and its width, depth and surface extension are designed to ensure that when the stop button 6 assumes its operational position the edge applies light pressure from below on the switch 17, which closes the circuit that controls the operational process of the mower 1. In the stop position, the pressure on the contact breaker 17 is released, in consequence of which the switch 17 opens the circuit concerned.

In addition to the rails 10 with tenons 12 thereon, the locking device likewise utilises two fixation means 13, which are hingedly attached to the body 9. The fixation means 13 are essentially flat and have a substantially rectangular shape and they are positioned horizontally, each in front of its respective short side of the front edge of the stop button 6, with one of their long sides facing the stop button 6. Obviously, the fixation means 13 could have a different shape, such as a triangular or polygonal shape or perhaps a circular ridge shape. At the short sides of the fixation means 13 that face the centre of the mower 1 the fixation means 13 are pivotally attached to the body 9 via a pivot pin. A torsion spring 15 is arranged about said pivot pin so as to serve to hold the free end of the fixation means 13, i.e. the short end not attached to the body 9 via a pivot pin, constantly tensioned in the direction of the stop button 6. Centrally located in the free end wall of each fixation means 13 a recess 14 is formed, the configuration of which fits that of the previously mentioned tenons 12 on the rails 10. The fixation means 13 serve to keep the sliding shutter 7 in its closed position, which is effected by the recess 14 blocking the movements of the sliding-shutter rails 10 along the guide ridges 11 by maintaining the tenon 12 inside the recess 14. The locking of the pivotal movement of the fixation means 13 is in turn controlled by the stop button 6, the operational and stop positions of which affect the operation of the device as will be described in more detail in the following with reference to Figs 3a-3d.

In Figs 3-3d, the upper drawing figures show in views from above the lawn mower 1 with the lid 3 removed whereas the bottom drawing figures are perspective views of the stop button 6, the sliding shutter 7 and the components of the locking device. In each figure, the entire mower 1 as also the lid system are shown in the same position. In Fig 3a, the operational position of the stop button is shown in the stage, when the sliding shutter 7 is locked in its closed position and the operational process of the mower could be active. The arrow shown in this drawing figure indicates the direction of the force that the user needs to exert on the stop button 6 to release the locking mechanism.

In Fig 3b the stop button 6 assumes its stop position and thus the switch 17 is disconnected from the current supply and in consequence thereof the operational process of the mower 1 is interrupted. The locking device has opened the sliding shutter 7, giving the user access to the control panel 25. In Fig 3c, the sliding shutter 7 is still open but it has been pushed forwards in the direction of travel of the mower 1 up to the point when its tenons 12 on the rails 10 assume a position in which they only just abut against the recess 14 formed in the fixation means 13. The circuit of the switch 17 is still open and the operational process of the mower 1 is prevented thereafter. Fig 3d, finally, shows the position at the moment when the stop button 6 resumes its operational position by "shooting" upwards into its vertically upper position, thus closing the circuit energising the operational process as a result of the sliding shutter 7 being pressed forwards by the user and bringing along in its movement the fixation means 13 via the tenons 12 and the recesses 14. In Fig 3 a, the sliding shutter 7 together with the rails 10 and the tenons 12 is kept in position by the recesses 14 formed in the fixation means 13. In turn, the fixation means 13 are kept in position by the stop button 6 owing to the provision on the forwards edge of the stop button 6 of two shoulders 26 having an almost triangular shape as seen from above, one such shoulder being provided adjacent each fixation means 13. These shoulders 26 are formed with a flat top face and with an essentially vertical edge in common with the stop button 6 along the front face of the stop button 6. An essentially vertical face of the shoulder is turned forwards in the direction of travel of the mower 1 and a second essentially vertical face of the shoulder is turned outwards towards the side, away from the centre of the mower 1. This second face/edge forms a means, against which abuts a vertically widening flange portion 27 on the fixation means 13, and in the operational position this flange portion thus prevents the fixation means 13 from being turned inwards by the spring 15 against the stop button 6.

In Fig 3 b the stop button 6 has been depressed, and in consequence thereof the switch 17 opens the circuit and the shoulder 26 is moved vertically to a position below the flange portion 27 and consequently it is disengaged therefrom. This allows the fixation means 13 to be turned by the action of spring 15 rearwards as seen in the direction of travel of the mower 1, releasing the tenon 12 and thus also the sliding shutter 7. The fixation means 13 is turned rearwards by the spring 15 until it abuts against a shoulder 23 formed on the front face of the stop button 6. As a result of this turning movement, not only does the sliding shutter open but it is also forced upwards because the rails 10 are brought along by the movement of the fixation means 13. In addition, the control panel 25 is exposed. In order to prevent the springs 16 below the stop button 6 from forcing the stop button 6 to resume its vertically upper position as soon as the user ceases to depress the button, the top face 22 of the shoulders 26 act as stop faces, which during the upwards movement of the stop button 6 abut from below against the protrusions 24 projecting from the fixation means 13. Because the fixation means 13 are fixed vertically, the stop button 6 is prevented from resuming its operational position until such time as the fixation means 13 are again turned back to their original positions and thus the protrusions 24 again expose the shoulders 26, allowing the stop button 6 free passage to again "shoot" upwards. In Fig 3c, the sliding shutter 7 has been moved forwards by the user from the maximum open, rearwards position and by means of the tenons 12 on the rails 10 it only just abuts against the recesses 14. The switch 17 is still open and the circuit disconnected.

In Fig 3d, finally, the user's pushing forwards of the sliding shutter 7 via the rails 11, the tenons 12 and the recesses 14 forces the fixation means 13 to turn back to their original positions. Simultaneously with the turning movement of the fixation means 13 also the protrusions 24 are turned aside, exposing the shoulders 26 and the stop button 6 assumes its vertically upper, operational position. The switch 17 then closes the circuit. The operational process of the mower 1 may now start, should the control panel 25 be set therefor.

As should be appreciated, many modifications of the embodiment above are possible within the scope of protection of the invention as defined in the appended claims. The above preferred embodiment has been described above for exemplifying and not restricting purposes. For example, the contact breaker 17 could be disposed in such a location on the stop button 6 that it becomes possible to start the operational process of the mower 1 without closing the sliding shutter 7 and thus raise the stop button 6 to its operational position. At the same time it should be possible to arranged the contact breaker 17 in otiier positions, wherein it could still be affected by the movement of the stop button 6 but more indirectly. For example on a part of the rails 10 the movement of which is a direct function of the depression of the stop button 6.

The contact breaker 17 may be configured in various ways, for example as a spring- loaded pressure transducer but could also be of a type different from the above mentioned electrical contact breaker, for example a Hall transducer which operates on the potential difference in a magnetic field. The stop button 7 and the contact breaker 17 could likewise be arranged to unlock a key-operated lock for a control panel 25. The safety device in accordance with the invention likewise could be arranged in such a manner that when the working implement 1 is made operational, the protective shutter 7 is not completely closed, i.e. the control panel is partly accessible also when the working implement 1 is operational. A safety device in accordance with the present invention may also be used in several other fields of application than in an automatic self-propelling lawn mower 1. The safety device may be used in all kinds of moving working implements, particularly of the kind that are not controlled completely by the user, such as an automatic self-propelling vacuum cleaner.

The handling object 25 could likewise be for instance a filler cap in a working implement, a set of electrical fuses or an object for exchange of or access to parts of the working implement. By the latter are intended for instance components in an engine or in propelling means, or control means such as a data card, which it must be easy to replace but the position and function of which are such that the operational process of the working implement must be interrupted for such replacement could be effected. Also the sliding shutter 7 could be designed differently. For example, it could be rotationally attached to a pivot pin disposed at right angles to its plane of extension and thus be rotated about said pivot pin to expose the handling object 25 underneath. In accordance with a further variety it could be a foldable lid, which is kept down by a locking device, which in turn is affected by the stop button 6.

The stop button 6 could also be designed as a rotary control and it could also function as a locking device/fixation means for a sliding or foldable lid. The various types of lids or shutters may be placed not only horizontally or at an angle on a top surface of the working implement but also vertically or at an angle on a side face or rear face of the working implement.

Claims

1. A safety device in working implements (1) comprising at least one handling object (25), characterised in that said handling object (25) may be covered by a lid (7), which is actively connected to an out of service-taking means (6), whereby said handling object (25) is essentially inaccessible until said out of service-taking means (6) has made the working implement inoperative.

2. A safety device as claimed in claim 1, characterised in that the lid (7) may assume a closed position and an open position, and in that in said closed position the operational process (1) of said working implement may be started but not before, upon transition to the open position, the function of said out of service-taking means (6) to interrupt the working process of the device (1) is first activated.

3. A safety device as claimed in claim 2, characterised in that the second position of the lid (7) means that the out of service-taking means (6) is activated and the working process of the working implement (1) is interrupted.

4. A safety device as claimed in any one of the preceding claims, characterised in that the working process of the working implement (1) is arranged to start only when the lid (7) is being closed.

5. A safety device as claimed in any one of the preceding claims, characterised in that said handling object (25) is accessible to the user from the vertically upper face of the working implement (1).

6. A safety device as claimed in one of the preceding claims, characterised in that the lid (7) is a sliding shutter.

7. A safety device as claimed in any one of the preceding claims, characterised in that the means (6) for preventing the operation of the working implement is configured as a push button.

8. A safety device as claimed in any one of the preceding claims, characterised in that a contact breaker (17) is coupled to the out of service-taking means (6), whereby the operation of the working process of the working tool (1) is interrupted upon activation of the out of service-taking means (6).

9. A safety device as claimed in any one of claims 2-8, characterised in that the safety device comprises a fixation means (13), which is operatively connected between the out of service-taking means (6) and the lid (7) in such a manner that upon operation of the working process of the working implement (1) said fixation means fixes the lid (7) in a closed position and upon interrupted operation of the working process of the working implement (1) it fixes the out of service-taking means (6) in an activated position.

10. A safety device as claimed in claim 9, characterised in that the fixation means (13), upon activation of the out of service-taking means (6), transfers an activation force for opening of the lid (7).

11. A safety device as claimed in claim 10, characterised in that the lid (7) comprises at least one protrusion (10), which is actively coupled to the fixation means (13) in such a manner that the activation force acts via said protrusion (10) upon activation of the out of service-taking means (6) for opening of the lid (7).

12. A safety device as claimed in claim 11, characterised in that said at least one protrusion (10) is formed integrally with the lid (7) and is displaced in the same direction as the latter.

13. A safety device as claimed in any one of the preceding claims, characterised in that the working implement (1) is a gardening implement.

14. A safety device as claimed in any one of the preceding claims, characterised in that the working implement (1) is an automatically, self-propelling lawn mower.

15. A safety device as claimed in any one of the preceding claims, characterised in that said handling object (25) is a control panel for controlling the operational process of the working implement ( 1 ) .

16. A safety device as claimed in any one of the preceding claims, characterised in that said handling object (25) is a filler cap.

17. A safety device as claimed in any one of the preceding claims, characterised in that said handling object (25) is a panel comprising electric fuses.

18. A safety device as claimed in any one of claims 7-17, characterised in that the colouring of the out of service-taking means (6) is substantially distinguished from that of the working implement ( 1 ) .

19. A safety device as claimed in any one of claims 7-18, characterised in that the fixation means (13) is an essentially flat, essentially rectangular plate, said plate being pivotally connected at one of its short ends to the working implement (1) via a pivot pin.

20. A safety device as claimed in claim 19, characterised in that the fixation means (13) is formed with a recess (14) at its opposite short end, said recess engaging a tenon (12) formed on the protrusion (10) on the lid (7).

21. A safety device as claimed in any one of claims 19-20, characterised in that the fixation means (13) is rotationally resiliently mounted in the working implement (1) in such a manner that said fixation means (13) tends to open the lid (7).

22. A safety device as claimed in any one of claims 7-21, characterised in that the out of service-taking means (6) is resiliently mounted in the working implement in such a manner that said out of service-taking means (6) is biased for movement outwards from the working implement (1).

23. A safety device as claimed in any one of claims 7-22, characterised in that the out of service-taking means (6) comprises at least one shoulder (26), which is arranged, when the out of service-taking means (6) is not activated, to prevent the fixation means (13) from opening the lid (7).

24. A safety device as claimed in any one of claims 7-23, characterised in that said shoulder (26) becomes inactive upon transition from the closed to the open position of the lid (7).

25. A working implement (1), characterised in that it comprises a safety device in accordance with any one of claims 1-24.

26. A working implement (1) as claimed in claim 25, characterised in that the working implement (1) is an automatically, self-propelling lawnmower.