The present invention relates to a device according to the preamble to appended claim 1.
Seating- and standing tables and similar arrangements are being increasingly used at different workplaces and also in the home. The prior art structures are provided with different types of jamming protection, whereby the drive units (drive motors) are disabled in the event of a risk of a jamming or pinching injury. Such prior art structures are illustrated in publications SE 516 479, US 2005/0012430 and US 2005/0082997 A1. However, these prior art structures have proved to display insufficient sensitivity to slight loads above the normal load which is carried by the table top. This also applies to so-called point or concentrated loads and oblique loads. In addition, the prior art structures have proved to suffer from defective mechanical stability.
The task forming the basis of the present invention is to improve the prior art structures by obviating the drawbacks as outlined above.
This task is solved in the device disclosed by way of introduction in that it has been given the characterising features as set forth in the appended claims.
A device according to the present invention affords major possibilities for great mechanical stability without jeopardising sensitivity to such slight loads as occur in the event of a pinch or jamming risk during adjustment of the table top for changing the level of the table top above a standing or seating surface, and thereby the working height. Thus, the present invention makes for a considerably safer and more sensitive structure than prior art structures without in any jeopardising the desired mechanical stability. Further, a device according to the present invention makes for considerably greater versatility in the utilisation of the movement sensing and adjustment of the different drive units.
Embodiments of the present invention will be described in greater detail hereinbelow with reference to the accompanying Drawings.
FIG. 1 is a photographic representation of a table frame for the application of a device according to the present invention.
FIG. 2 is a perspective view of a part of a table with a device according to one embodiment of the present invention.
FIG. 3 is a view similar to FIG. 2 with the parts separated from one another.
FIG. 4 is substantially a similar view to FIG. 2 of another embodiment of a device according to the present invention with the parts separated from one another.
FIG. 5 is a section taken through a part of the embodiment of FIG. 4.
FIG. 6 is a section taken in the direction of the arrows VI in FIG. 5.
FIG. 7 is a perspective view of a detail of the part shown in FIGS. 5 and 6.
FIG. 8 is a perspective view of a part of a table frame with a device according to a further embodiment of the present invention.
FIG. 9 is a perspective view of a part of a table frame with a device according to yet a further embodiment of the present invention.
FIG. 10 is a perspective view on a larger scale of a part of the device according to FIGS. 8 and 9.
FIG. 11 is a section similar to FIG. 5 of a variation of the embodiment shown in FIG. 5.
FIG. 12 is a section taken along the line XII-XII in FIG. 11.
FIG. 13 is a perspective view on a larger scale of a part of the embodiment of the device in FIGS. 11 and 12.
FIG. 1 shows a table frame for a standing and seating table of per se known type. The table frame has two legs 1 and 2, each with its foot 3 and 4. The legs 1 and 2 are interconnected to one another by means of longitudinal beams 5 and 6. These support a drive unit 8, 9 at each leg 1, 2, as well as a bracket 10 and 11. A table top of in principle optional contour rests on the brackets 10 and 11, as well as the longitudinal beams 5 and 6. The table top may be rectangular or curved in different suitable ways, with a view to permitting a comfortable and efficient working position. The drive units 8 and 9 include as a rule an electric motor which, via a gear, is connected to a screw which extends down into the legs 1, 2. The drive units 8, 9 are as a rule powered by means of a suitable electronics unit, which is connected to a suitable power source, e.g. the standard power mains, and which by means of a suitable button cluster or set is actuable for adjusting of the table top upwards or downwards. The illustrated table frame supports a table top 14.
FIGS. 1 and 2 show only a part of a table with the device according to the present invention, and it will be apparent from the Figures that the legs 1 and 2 are of the telescopic type, with an inner portion 12 and an outer portion 13. The table top 14, which may be manufactured from any optional material and, as in FIGS. 1 and 2, may be assumed to be manufactured from a transparent material, so that the brackets 10, 11 and the longitudinal beams 5 and 6, as well as the drive units 8 and 9, are visible through the top.
Between the bracket 10 and the drive unit 8, there is mounted a movement sensor 15 which, via a cable 16, is connected to the electronics unit for supplying driving current to the drive unit 8. The movement sensor 15 is mounted, on the one hand, on the bracket 10 by means of bolts 15A and, on the other hand, on the drive unit 8 by means of bolts 15B. Thus, the movement sensor 15 is disposed between mutually movable parts, i.e. the table top 14 and the table legs 1, 2. The bracket 10 is mounted on the drive unit 8 by means of two bolts 17 and 18 which extend through the bracket 10 and each through a ring, washer or gasket 19 and 20. Further, the longitudinal beams 5 and 6 are mounted on the drive unit 8 by means of bolts 21, 22 and 23, 24, which extend through holes in the beams 5 and 6 and each through its ring, washer or gasket 25, 2627, 28 to threaded holes in the drive unit 8, which is connected to the electronics unit via a cable 29. The latter threaded holes need not, naturally, be located in the drive unit 8 proper, but for example in a bracket therefor. The rings, the washers or the gaskets 19, 20, 25, 26, 27, 28 may extend in bushing-like fashion into and possibly through the holes in the brackets 10 and the longitudinal beams 5, 6 for the bolts 17, 18, 21, 22, 23, 24. The arrangement at the other table leg 2 is in principle identical to the arrangement illustrated in FIG. 3.
As a result of the device in FIG. 3, the table top 14 will thus in principle be movably mounted on the drive unit 8 with the aid of the elastomeric parts in the form of the rings, the washers or the gaskets 19, 20, 25, 26 and 27, 28, of which the latter may also be designated pads or cushions. Possible movement between the table top and the drive unit 8 and the table leg 1 or the table leg part 13 will thus be transmitted to the movement sensor 15 or, in other words, be exercised on it, and such a possible movement will result in a signal which is fed via the cable 16 to the electronics unit and which disconnects supply of the driving current to the drive unit 8. This will occur in the event of a risk of pinching or jamming.
The embodiment of a device according to the present invention illustrated in FIG. 4 has its drive unit disposed in the table leg 1. On the underside of the table top 14, there is disposed a fixing plate 30 which is mounted on the fixing plate 31 of the drive unit 8 via a movement sensor 32 which is shown in greater detail in FIGS. 5, 6 and 7. The movement sensor 32 displays a moving part 33 which is fixed in the table top 14 via the mounting plate 30. This, as it were, moving part 33 is secured in pads 34 and 35 which consist of elastomeric material, e.g. rubber or other similar material, and which are secured in a mounting member 36 which is fixed on the plate 31 of the drive unit 8. Between the moving part 33 and the mounting plate 36, there is disposed a strain element 37 which supports a strain gauge 38 and which is secured on the moving part 33.
The strain element 37 is shown in greater detail in FIG. 7. The strain element is designed so as to permit large movement where the strain gauge 38 is positioned. The signal from the strain gauge 38 is fed to the electronics unit via the cable 16. The strain gauge 38 is further positioned so as to receive mechanical protection against damage in the event of extreme movement amplitudes between the parts 33 and 36. The protected positioning of the strain gauge 38 will further permit the employment of more sensitive indicators that has hitherto been possible.
In the embodiment of the device according to the present invention illustrated in FIG. 8, the longitudinal beams 5, 6 are fixedly mounted on the drive unit 8 by means of bolts 39, 40, 41, 42. The bracket 10, on which the table top rests, is fixed with a certain play on the drive unit 8 by means of bolts 43, 44, each of which extends through a first washer 45 and a second washer 46, a hole 47 in the bracket 10 to a fixing hole 48 in the drive unit 8 as intimated by means of ghosted lines. The second washer 46 is elastomeric and fits at least partly in the hole 47 and may therefore be considered as a bushing therein. The movement sensor 15 displays a pin 49 which freely extends through a hole 50 in the wall of the drive unit 8 into engagement with the bracket 10 e.g. a hole 51 in the bracket 10. The pin is suitably provided with a cap or hat 52 for tolerance completion and thereby elimination of possible movements between the pin 49 and the bracket 10.
The embodiment illustrated in FIG. 9 is substantially alike the embodiment illustrated in FIG. 8, apart from the fact that the longitudinal beams 5, 6 are fixed in the drive unit 8 with a certain play in relation thereto in fundamentally the same manner as the bracket 10 in FIG. 8. Thus, the beams 5,6 are fixed on the drive unit 8 by means of bolts 53, 54, 55, 56 which each extend through a first sleeve 57, a second sleeve 58, a third sleeve 59 and through a hole 60 in the longitudinal beam 5, 6. The sleeves 57, 58, 59 fit into one another and in the hole 60 and the length corresponds substantially to the thickness of the longitudinal beam 5, 6, so that movement between the longitudinal beams 5, 6 and the drive unit 8 is permitted in the same manner as between the bracket 10 and the drive unit 8. The second sleeve 58 is of elastomeric material, and may be considered as a bushing.
FIG. 10 shows the movement sensor 15 in greater detail. The movement sensor 15 has a body 61 which is designed in a manner suitable for its purpose and which supports a strain gauge 62. At the one end of the body 61, the previously mentioned pin 49 is secured therein. The pin 49 is not required in all practical applications. Further, the body 61 is provided with a number of mounting holes 63, 64, 65, 66. The strain gauge element 62 is connected to a connection means 67 by the intermediary of wires 68.
The embodiment of a device according to the present invention illustrated in FIGS. 11, 12 and 13 is in principle similar to the embodiment illustrated in FIGS. 5, 6 and 7, apart from the fact that the movement sensor 32 is of the type illustrated in FIG. 10. In this practical application, the pin 49 is however omitted, since the body 61 is fixed on the mounting plate 36 by means of a bolt 69 and a spacer 70, and on the moving part 33 by means of a bolt 71 and a spacer 72. The bolts 69, 71 and the spacers 70, 72 contribute to a fixed union between the body 61 and the mounting plate 36, as well as the moving part 33. All parts display the same reference numerals in the different Drawing Figures.
The movement sensors or strain gauge elements may be of different types, for example wire strain gauges, piezoelements, etc. Further, they should preferably be of the self-calibrating type so that account is taken of any possible static load such as working equipment placed on the table top. The present invention permits the use of extremely sensitive indicators, since they are positioned with mechanical protection. The parts of the elastomeric material between the parts fixedly connected to the movement sensors and the parts substantially fixedly connected to the table top afford a certain mechanical protection of the movement sensors, but also contribute to realising a more uniform signal.
Numerous modifications are naturally conceivable without departing from the scope of the inventive concept as this is defined in the appended claims.
Patent Application
20110168064
