Electromotive linear drive in the form of a dual drive

Abstract

An electromotive linear drive in the form of a dual drive adjust movably mounted parts of reclining and seating furniture. Two threaded spindles (2, 3) driven by a worm gear and which are arranged one behind the other and flush with one another for displacing a lifting element. Bearings are provided at both ends of each threaded spindle (2, 3). The bearings are designed as roller bearings (4, 5) having an inner ring (6) and an outer ring (7). The aim of the invention is to design an electromotive dual drive in such a way that a short overall length is achieved and that the stability of the structure is increased. Said aim is achieved by arranging an abutment between both roller bearings (4, 5), which accommodate the spindle ends, on which the roller bearings are supported on from both sides.

Claims

1. An electric motor-actuated linear drive for adjusting moveably mounted parts of lying and seating furniture, comprising two threaded spindles (2, 3) drivable by way of a respective worm gear transmission and arranged in successive and mutually aligned relationship for displacement of a respective stroke element and bearings provided at both ends of each threaded spindle (2, 3), wherein at least the bearings arranged at the spindle ends which are close to each other are in the form of rolling bearings (4, 5) having an inner race (6) and an outer race (7), characterised in that arranged between the two rolling bearings (4, 5) which carry the spindle ends that are close to each other is a support means at which the rolling bearings are mutually supported from both sides.

2. An electric motor-actuated linear drive according to claim 1, wherein the support means is in the form of a plate (15).

3. An electric motor-actuated linear drive according to claim 2, wherein the plate (15) is of a diameter larger than the outside diameter of the outer race (7) of the rolling bearings (4, 5).

4. An electric motor-actuated linear drive according to claim 2, wherein the plate (15) has a central round opening (16) whose diameter is smaller than the inside diameter of the outer race (7) of the rolling bearings (4, 5).

5. An electric motor-actuated linear drive according to claim 4, wherein the diameter of the central round opening (16) of the plate (15) is larger than the outside diameter of the inner race (6) of the rolling bearings (4, 5).

6. An electric motor-actuated linear drive according to claim 1, wherein the support means or the plate (15) comprises metal.

7. An electric motor-actuated linear drive according to claim 6, wherein the support means or the plate (15) comprises steel.

8. An electric motor-actuated linear drive according to claim 6, wherein the support means or the plate (15) comprises a zinc or aluminium alloy.

9. An electric motor-actuated linear drive according to claim 1, wherein the support means or the plate (15) comprises plastic.

10. An electric motor-actuated linear drive according to claim 9, wherein the support means or the plate (15) comprises high-strength, fibre-reinforced plastic.

11. An electric motor-actuated linear drive according to claim 2, wherein the plate (15) is rectangular or square.

12. An electric motor-actuated linear drive according to claim 2, wherein the plate has rounded corners.

13. An electric motor-actuated linear drive according to claim 2, wherein the plate is round.

14. An electric motor-actuated linear drive according to claim 1, wherein ball bearings are provided as the rolling bearings (4, 5).

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The invention is illustrated by means of an embodiment by way of example in the drawing and is described in detail hereinafter with reference to the drawing.

(2) The single FIGURE shows a perspective view of an electric motor-actuated linear drive in the form of a dual drive, which serves for adjusting moveably mounted parts of lying and seating furniture, in particular for the hospital and care sector. For reasons of clarity of the drawing the housing and the stroke elements at both sides thereof have been omitted.

DETAILED DESCRIPTION OF THE INVENTION

(3) On the left-hand side of the drawing the individual transmission parts are assembled while on the right-hand side the parts are shown as an exploded view.

(4) Essentially the dual drive 1 comprises two successively and mutually alignedly arranged threaded spindles 2 and 3 which are drivable by way of a respective worm gear transmission and which serve for displacement of a respective stroke element (not shown) for adjustment of the moveable furniture parts.

(5) Provided at both ends of each threaded spindle 2 and 3 are corresponding bearings. It will be noted however that the drawing only shows the bearings arranged at the spindle ends which are close to each other, those bearings being in the form of rolling bearings 4 and 5 comprising an inner race 6 and an outer race 7.

(6) Arranged on each of the threaded spindles 2 and 3 is a guide body 8 which is carried non-rotatably and non-slidably on the respective threaded spindle 2 and 3.

(7) Of the two worm gear transmissions for driving the two threaded spindles 2 and 3 the drawing only shows the worm gears 9 mounted rotatably on the respective guide body 8. In addition the arrangement has a coupling element 10 which is axially displaceable but which is arranged non-rotatably relative to the respective worm gear and with which the respective worm gear 9 can be selectively coupled to and uncoupled from the associated guide body 8. The inside profile 11 of the coupling element 10 forms in that case, with a counterpart profile 13 provided on a flange 12 of the guide body 8, a dog coupling which can be selectively coupled and uncoupled by axial displacement of the coupling element 10.

(8) When the parts shown in the exploded view are assembled and the guide body 8 is fixed on the threaded spindle 2 or 3 respectively a stepped end 14 of the guide body 8 engages into the central opening of the inner race 6 in the respective rolling bearing 4 and 5.

(9) Arranged between the two rolling bearings 4 and 5 which carry the spindle ends that are close to each other is a steel plate 15, against which the two rolling bearings 4 and 5 bear from opposite sides. The plate 15 which is of a square configuration in the embodiment illustrated in the drawing is in that case selected to be of such a size that the outer races 7 of the rolling bearings 4 and 5 bear over their entire periphery against the plate 15. Alternatively the plate can also have rounded corners or can be completely round.

(10) The plate 15 has a central round opening 16 which passes through the plate 15. The diameter of the opening 16 is smaller than the inside diameter of the outer race 7 of the rolling bearings 4 and 5. This ensures that the outer races 7 of the rolling bearings 4 and 5 bear around same against the flat sides of the plate 15.

(11) In addition the diameter of the central round opening 16 in the plate 15 is larger than the outside diameter of the inner race 6 of the respective rolling bearing 4 and 5 so that the inner race does not come into contact with the plate 15.

(12) In the structure shown in the drawing the stepped end 14 of the guide body 8 also under some circumstances projects a distance beyond the inner race 6 of the respective rolling bearing 4 or 5 so that in that respect no damaging contact with the plate 15 occurs.

(13) The thickness of the plate 15 can be relatively thin. It is only necessary for the thickness of the plate 15 to be sufficient to prevent the rotating parts of the threaded spindles 2 and 3 and the guide body 8 coming into contact.

(14) The plate 15 can comprise steel or also high-strength plastic, for example fibre-reinforced plastic.

(15) The rolling bearings 4 and 5 are in the form of ball bearings.

(16) By virtue of the structure according to the invention the axial forces exerted on the threaded spindles 2 and 3 upon adjustment of the furniture parts are not transmitted to the housing and possible internal holding ribs, but the threaded spindles 2 and 3 are supported against the plate 15 from both sides by way of the ball bearings.

(17) It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.