DOMESTIC APPLIANCE HAVING SPRING-LOADED TOOLS

Abstract: In a domestic appliance (1) having a housing (3) and having drive means (4) for rotationally driving at least one tool (5, 6) which is held by a holding means (17,18) and which is drivable with the aid of the drive means (4) so as to be rotated about a tool axis (31, 32), the tool (5, 6) is guided so as to be movable parallel to the direction of the tool axis (31, 32) and at least one spring means (39, 40) has been provided which resiliently loads a tool (5, 6) during rotational driving of this tool, namely towards the free end (33, 34) of the tool (5, 6).

Description: Domestic appliance having spring-loaded tools The invention relates to a domestic appliance as defined in the opening part of claim 1. Such a domestic appliance is mentioned as prior art in the patent document CH 349 389 and is therefore known. The patent document CH 349 389 discloses a domestic appliance of a construction in which a tool is movable in an axial direction under the influence of gravity, so that under the influence of gravity at least this one tool is held in contact with the container wall, for example the bottom of a container for holding foodstuffs to be processed, in a more or less satisfactorily manner. The patent document CH 349 389 does not give any concrete details about the construction of the prior art as described in said patent document, so that the conclusion is obvious and permissible that also with this known construction the two tools are movable in axial directions under the influence of gravity. Though in many cases the movement of tools of a domestic appliance under the influence of gravity may lead to satisfactory results this is not always the case. For example, if the foodstuffs to be processed offer a comparatively high mechanical resistance to the tools, the tool load under the influence of gravity may be inadequate too keep all the tools applied to the bottom of a container which holds the foodstuffs to be processed. Moreover, this may give rise to jerky axial movements, which leads to an unpleasant feeling for the user who handles the domestic appliance and should therefore be regarded as not user-friendly. It is an object of the invention to preclude the afore-mentioned problems and to provide an improved domestic appliance. According to the invention, in order to achieve said object, a domestic appliance of the type defined in the opening part of claim 1 is characterized in that the characteristic features defined in the characterizing part of claim 1 have been provided. By the provision of the characteristic features according to the invention it is achieved in a comparatively simple as well as a very reliable and aging-resistant manner that each tool of a domestic appliance in accordance with the invention is held against a container wall, for example the bottom of a container for the foodstuffs to be processed, in the area of the tool end with a comparatively high reliability, which is mainly determined by the selected spring force of the spring means, as a result of which each tool always provides an optimum contribution to the processing result attainable with this tool. Moreover, the provision of a spring means substantially precludes jerky axial movements of each tool, which manifests itself in a pleasant feeling for a user handling the domestic appliance. In a domestic appliance in accordance with the invention a blade spring configuration or a torsion spring configuration but also a resilient rubber element can be used as spring means. However, it has proved to be very advantageous when a domestic appliance in accordance with the invention in addition has the characteristic features as defined in claim 2. Such a construction is very reliable, dependable and simple. In a domestic appliance in which each tool has an associated helical pressure spring, it has further proved to be very advantageous when in addition the characteristic features as defined in claim 3 are provided. This has proved to be advantageous in view of a compact construction which is resistant to undesired soiling of the helical pressure springs. In an appliance in accordance with the invention it has further proved to be particularly advantageous when in addition the characteristic features as defined in claim 4 are provided. In this way, it is achieved that the possibility of axially moving each tool of the domestic appliance against spring force can be blocked by a user of the domestic appliance. In a domestic appliance having blocking means it has proved to be advantageous when in addition the characteristic features as defined in claim 5 are provided. Practical tests have proved that such a construction is advantageous. In the above context it has proved to be particularly advantageous when a domestic appliance in addition has the characteristic features as defined in claim 6. Thus, movability for the sleeve holder is achieved in a simple manner. In a domestic appliance having blocking means it has further proved to be very advantageous when in addition the characteristic features as defined in claim 7 are provided. In this way, it is achieved that each tool held with the aid of an inner sleeve is accessible from the interior of the domestic appliance both when the blocking means are in their release position and when the blocking means are in their blocking position, i.e. accessible for ejection means with the aid of which the part of each tool inside an inner sleeve in the domestic appliance can be moved out the inner sleeve in order to enable the tool to be separated from the domestic appliance. The above-mentioned as well as further aspects of the invention will become apparent from the embodiment described hereinafter by way of example and will be elucidated with reference to this example. The invention will now be described in more detail with reference to the drawings, which show an embodiment given by way of example but to which the invention is not limited. Fig. 1 shows in a highly diagrammatical manner a domestic appliance in accordance with an embodiment of the invention during a mode of operation in which the tools of the domestic appliance are on the container wall of a mixing bowl. Fig. 2 shows a part of the domestic appliance of Fig. 1 in an oblique view from the top and from the rear. Fig. 3 is a front view as indicated by the arrow III in Fig. 2 and showing the part of the domestic appliance of Fig. 1 as shown in Fig. 2. Fig. 4 is an underneath view as indicated by the arrow TV in Fig. 3 and showing the part of the domestic appliance of Fig. 1 as shown in Figs. 2 and 3. Fig. 5 is a sectional view taken on the line V-V in Fig. 4 which, to an enlarged scale as compared with Figs. 2, 3 and 4, shows the part of the domestic appliance of Fig. 1 as shown in Figs. 2, 3 and 4. Fig. 6 shows, in the same way as Fig. 5, a detail of the domestic appliance of Fig. 1, which detail concerns drive means for driving the tool of the domestic appliance. Fig. 7 is an exploded view which shows the part of the domestic appliance of Fig. 1 as shown in Figs. 2, 3, 4 and 5. Fig. 1 is a domestic appliance 1 constructed for processing at least one foodstuff item present in a container 2. The container 2 is a mixing bowl. The domestic appliance 1 has a housing 3, which shown only diagrammatically in Fig. 1 and only partly in Fig. 2. The housing 3 accommodates drive means 4 for rotationally driving two tools 5 and 6 of the domestic appliance 1. In the present case the two tools 5 and 6 are formed by two beaters. In known manner, the drive means comprise an electric motor, which is not shown in the Figures and which is secured by means of a mounting plate P and four mounting pins B. A worm, which is neither shown in the Figures, is rotationally drivable by means of the shaft of the electric motor. This worm is in mesh with a first worm wheel 7 and a second worm wheel 8. Each worm wheel 9 or 10 is connected to an outer sleeve 9 or 10, respectively. The two outer sleeves are interposed between an upper first mounting shield 11 and a lower second mounting shield 12, the two outer sleeves 9 and 10 each having end portions 13, 14 and 15, 16, respectively, which have a diameter smaller than the rest of the respective outer sleeve 9 or 10 and which are rotatably mounted in the two mounting shields 11 and 12. The two mounting shields 11 and 12 are fixedly connected to the mounting plate P. In this way, the two outer sleeves 9 and 10 are mounted so as to be rotationally drivable and basically immovable in axial directions. In each of the outer sleeves 9 and 10 an inner sleeve 17 or 18, respectively, is arranged, the inner sleeves 17 and 18 being guided so as to be movable in axial directions with respect to the outer sleeves 9 and 10. The inner sleeves 17 and 18 each form a holding means for respectively holding a tool 5 or 6. The first inner sleeve 17 as well as the second inner sleeve 18 each have eight coupling ribs 19 and 20, which each engage in a corresponding coupling slot 21 and 22, respectively, in the first outer sleeve 9 and in the second outer sleeve 10, respectively. Thus, the outer sleeves 9 and 10 and the inner sleeves 17 and 18 are locked in rotation with the aid of the coupling ribs 19 and 20 and with the aid of the coupling slots 21 and 22, as a result of which the inner sleeves are rotationally drivable with the aid of the outer sleeves 9 and 10. A pin 23 or 24 projects laterally from each respective one of the two inner sleeves 17 and 18 in a radial direction and thus engages in an axial recess in the respective outer sleeve 9 or 10, which recesses are not shown in the drawings. The laterally projecting pins 23 and 24 and the recesses which cooperate with these two pins 23 and 24 limit the axial range of movement of the inner sleeves 17 and 18 with respect to the outer sleeves 9 and 10. As already stated, the inner sleeves 17 and 18 each form a holding means for holding a tool 5 or 6, respectively. Locking hooks 25 and 26 have been provided to retain a tool and enable the tools 5 and 6 to be retained in an interlocking fashion. The two tools 5 and 6 will now briefly be described in more detail. The two tools 5 and 6 each have a tool shank 27 or 28, respectively, mixing elements 29 and 30 which cross one another being connected to each tool shank 27 and 28. Via the tool shanks 27 and 28 the two tools 5 and 6 are drivable with the aid of the drive means 4 so as to be rotatable about tool axes 31 and 32 which extend parallel to one another. The two tools 5 and 6 project from the housing 3 of the domestic appliance 1 , namely in the manner which is apparent in particular from Fig. 1. The mixing elements 29 and 30, which cross one another, are interconnected in the area of the ends of the mixing elements 29 and 30 which are remote from the housing 3 and the two tool shanks 27 and 28, i.e. in the area of the free ends 33 and 34 of the two tools 5 and 6. Adjacent its free end 35 or 36 of the mixing elements 29 or 30, respectively, each tool shank 27 or 28 has a recess 37 or 38 adapted to cooperate with the respective locking hook 25 or 26. The two tools 5 and 6 of the domestic appliance 1 are guided so as to be movable parallel to the directions of the tool axes 31 and 32, which is achieved with the aid of the inner sleeves 17 and 18, which are guided so as to be movable in axial directions with respect to the outer sleeves 9 and 10, namely by means of the coupling ribs 19 and 20 and by means of the coupling slots 21 and 22. The excursions of the inner sleeves 17 and 18 and, consequently, of the tools 5 and 6 are limited with the aid of pins 23 and 24 which project laterally from the inner sleeves 17 and 18 and with the aid of recesses in the outer sleeves 23 and 24, which recesses cooperate with these pins 23 and 24. The domestic appliance 1 further has spring means 39 and 40, the spring means 39 and 40 loading the tools 5 and 6 resiliently during the rotation of the tools 5 and 6 in such a manner that the free end portions 33 and 34 of the tools 5 and 6 are resiliently loaded parallel to the directions of the tool axes 31 and 32 and away from the housing 3 of the domestic appliance 1. The spring means 39 and 40 are each formed by a respective helical pressure spring 39 or 40, each of the tools 5 and 6 having such an associated helical pressure spring 39 or 40, and each tool 5 or 6 and its associated helical pressure spring 39 or 40 being coaxial with one another. In the present case, as is apparent particularly from Figs. 5 and 6, a helical pressure spring 29 or 30 is mounted coaxially on each inner sleeve 17 or 18, for which purpose each inner sleeve 17 or 18 has a sleeve portion 41 or 42, respectively, having a part of a diameter which is small in comparison with the coupling ribs 19 and 20. Each of the helical pressure springs 39 and 40 acts upon a respective one of the inner sleeves 17 and 18 at one end and upon a respective one of the outer sleeves 9 and 10 at the other end. As a result of the fact that in the domestic appliance 1 the inner sleeves 17 and 18 are guided so as to be axially movable with respect to the outer sleeves 9 and 10 and that the inner sleeves 17 and 18 are moved against the force of the helical pressure springs 39 and 40, it is achieved in a simple, very reliable and also aging-resistant manner that in the area of their free ends the tools 5 and 6 can suitably adapt their height positions to the shape of the container wall of a container 2, which guarantees that the tools 5 and 6 are held against the container wall of the container 2 in the area of their free ends 33 and 34 with a comparatively o high reliability, which is by the force of the spring means 39 and 40. As a result of this, it is achieved that both tools 5 and 6 always provide a substantial contribution to the processing of the foodstuffs in the container 2. Moreover, it is thus achieved with the aid of the spring means 39 and 40 that in the area of their free ends 33 and 34 the two tools 5 and 6 remains practically always applied to the container wall of the container 2 and are safeguarded against jerky movements in axial directions with the aid of the spring means 39 and 40, which manifests itself in a pleasant feeling for a user handling the domestic appliance 1. As regards Fig. 6 it is to be noted that this Figure represents a situation in which the second tool 6 is shown in an axially unchanged operating position in which the second tool 6 is held by the force of the second helical pressure spring 40, while the first tool 5 is shown in an axially changed operating position in which the first helical pressure spring 39 has been compressed. The difference in position between the two tools 5 and 6 is indicated by the reference symbol H in Fig. 6. In order to enable the possibility of axially moving the inner sleeves 17 and 18 and, consequently, the tools 5 and 6 against spring force to be blocked by a user of the domestic appliance 1 the domestic appliance 1 in addition has blocking means 43. To actuate the blocking means 43 the blocking means 43 include a pin-shaped actuating element 44. When the blocking means 43 have been set into their blocking position the inner sleeves 17 and 18 and, consequently, the tools 6 and 7 are blocked against a movement of the tools 6 and 7 against the force of the spring means 39 and 40, i.e. against the force of the helical pressure springs 39 and 40. The blocking means 43 include a sleeve holder 45. The sleeve holder 45 is arranged to be movable transversely to the directions of the tool axes 31 and 32 so as to allow the blocking means 43 to be moved between their blocking position and their release position. In the present case, the sleeve holder 45 is arranged to be pivotable about a pivotal axis 46 which extends parallel to the directions of the tool axes 31 and 32. For this purpose, a shaft 47, which is coaxial with the pivotal axis 46, is connected to the sleeve holder 45, which shaft is pivotably mounting with the aid of appliance-mounted supporting means, which are not described any further herein. The pin-shaped actuating element 44 projects laterally from the shaft 47 in a radial direction. The sleeve holder 45, which is substantially bar-shaped in plan view and which has rounded ends, has two holes 48 and 49, which are coaxial with respective axes 50 and 51. Two blocking sleeves 52 and 53 are connected to the sleeve holder 45, the first blocking sleeve 52 being coaxial with the first hole 48 and the second blocking sleeve 53 being coaxial with the second hole 49. The first blocking hole 52 has been provided for the first tool 5 and the second blocking tool 53 has been provided for the second tool 6. When the blocking means 43 have been set to their blocking position the blocking sleeves 52 and 53 are each coaxial with a respective inner sleeve 17 or 18, as is apparent particularly from Fig. 5. As soon as the blocking means 43 and, consequently, the two blocking sleeves 52 and 53 are in their blocking positions, the blocking sleeves 52 and 53 have only a very small axial clearance from the inner sleeves 17 and 18, as is also apparent from Fig. 5, as a result of which in this case the inner sleeves 17 and 18 are blocked and the inner sleeves 17 and 18 cannot be moved against the force of the spring means 39 and 40. In this case the tools 5 and 6 are likewise blocked against axial movement in opposition to the force of the spring means 39 and 40, as a result of which the free ends 33 and 34 of the two tools 5 and 6 are invariably held at the same axial level. Finally, it is to be noted that the domestic appliance 1 has an ejection mechanism 54, which is commonly known in such domestic appliances. The ejection mechanism 54 has an ejector mount 55 to which two ejector pins 56 and 57 are connected. The first ejector pin 56 is coaxial with the tool axis 31 of the first tool 5. The second ejector pin 57 is coaxial with the tool axis 32 of the second too 6. A return spring 58 or 59 in the form of a helical pressure spring is arranged on each of the two ejector pins 57 and 57. The two return springs 58 and 59 have one end which acts upon the ejector mount 55 and another end which acts upon a respective abutment plate 60 or 61, which is mounted stationarily in the domestic appliance 1, as can be seen in Figs. 2 and 5. An actuating element 63 which takes the form of a push-button is connected to the ejector mount 55 via a connecting member 62. The ejector mount 55 is movable against the force of the return springs 58 and 59 by the actuation of the actuating element 63. In this way, the ejector pins 56 and 57 are also movable in a direction towards the free ends 33 and 34 of the two tools 5 and 6, as a result of which the ejector pins 56 and 57 can be brought into operative engagement with the free ends 35 and 36 of the tools 5 and 6 and thereby release the interlocking engagement between the recesses 37 and 38 and the locking hooks 25 and 26, as a result of which the tools 5 and 6 slip out of the inner sleeves 17 and 18 when the actuating element 63 is actuated and, as a consequence, the tools 5 and 6 are separated from the rest of the domestic appliance 1. The invention is not limited to the example of an embodiment described hereinbefore. The characteristic features of the invention may, for example, also be provided o in a domestic appliance having only one rotationally drivable tool or more than two rotationally drivable tools, for example three or four rotationally drivable tools. Moreover, guiding of the tools in an axial direction may be realized by means of a different construction. Furthermore, differently constructed spring means may be provided, for example wire springs or cup springs and the like.

Claims: CLAIMS: 1. A domestic appliance (1) constructed to process at least one foodstuff item present in a container (2), and having a housing (3), and having drive means (4), accommodated in the housing (3), for rotationally driving at least one tool (5, 6) of the domestic appliance (1), and having at one tool (5, 6) which is held by a holding means (17, 18) of the domestic appliance (1) and then projects from the housing (3), which tool is drivable so as to be rotated about a tool axis (31, 32) with the aid of the drive means (4), is guided so as to be movable parallel to the direction of the tool axis (31, 32), and has a free end (33, 34) which is remote from the housing (3),characterized in that at least one spring means (39, 40) has been provided, and the at least one spring means (39, 40 resiliently loads the at least one tool (5, 6) during rotational driving, namely in such a manner that the free end (33, 34) of the tool (5, 6) is resiliently urged away from the housing (3) parallel to the direction of the tool axis (31, 32). 2. A domestic appliance (1) as claimed in claim 1, characterized in that each spring means (39, 40) is formed by a helical pressure spring (39, 40) and a helical pressure spring (39, 40) is associated with each tool (5, 6), and each tool (5, 6) and its associated helical pressure spring (39, 40) are aπanged so as to be coaxial with one another. 3. A domestic appliance (1) as claimed in claim 2, characterized in that for each tool (5, 6) a rotationally drivable outer sleeve (9, 10), which is mounted so as to be basically immovable in axial directions, has been provided, and an inner sleeve (17, 18) is aπanged in each outer sleeve (9, 10), and each inner sleeve (17, 18) forms a holding means (17, 18) for holding a tool (5, 6), and each inner sleeve (17, 18) is rotationally drivable by the respective outer sleeve (9, 10) and is guided in the respective outer sleeve (9, 10) so as to be movable in axial directions, and a helical pressure spring (39, 40) is mounted coaxially on each inner sleeve (17, 18), which spring acts upon the inner sleeve (17, 18) at one end and upon the outer sleeve (9, 10) at the other end. 4. A domestic appliance (1) as claimed in claim 1, characterized in that blocking means (43) have been provided, and the blocking means (43) are movable between a blocking position and a release position, and each tool (5, 6) , when the blocking means (43) are in their blocking position, is blocked against movement of the tool (5, 6) against the force of the spring means (39, 40) which loads the tool (5, 6). 5. A domestic appliance (1) as claimed in claim 4, characterized in that the blocking means (43) include a blocking sleeve (52, 53) for each tool (5, 6), and each blocking sleeve (52, 53) is connected to a sleeve mount (45), and the sleeve mount (45) is aπanged so as to be movable transversely to the direction of the tool axis (31, 32), to allow the blocking means (43) to be moved between their blocking position and their release position. 6. A domestic appliance (1) as claimed in claim 5, characterized in that the sleeve mount (45) is aπanged so as to be pivotable about a pivotal axis (46) which is oriented parallel to the direction of the tool axis (31, 32). 7. A domestic appliance (1) as claimed in claim 5, characterized in that each blocking sleeve (52, 53) is coaxial with an inner sleeve (17, 18) when the blocking means (43) are in their blocking position. 8. A domestic appliance (1) as claimed in claim 1, characterized in that at least two tools (5, 6) have been provided, and the at least two tools (5, 6) are guided so as to be movable parallel to the directions of the tool axes (31, 32), and at least two spring means (39, 40) have been provided, which spring means (39, 40) load the tools (5, 6) resiliently.

Inventors: BOER HARRY, KRALL HANS P, RATTENBERGER BERNHARD, TEN HORN VINCENT, BOER, HARRY, KRALL, HANS, P., RATTENBERGER, BERNHARD, TEN HORN, VINCENT
Applicants: KONINKL PHILIPS ELECTRONICS NV, KONINKLIJKE PHILIPS ELECTRONICS N.V.
Application year: 2000
Main classification: A47J43
IPC codes: A47J43, B01F7