DE20116957U1 - castor - Google Patents

Description

Utility model application

Castor

Tente-RoUen GmbH & Co.

Herrlinghausen 75 D-42929 Wermelskirchen

VGN 265 098 24192DE mue/pa/g October 15, 2001 .··.: : : : .:

Castor

The invention relates firstly to a swivel castor with a wheel, a fork and a guide pin, wherein the fork can be pivoted relative to the guide pin and a spring arm is attached to the fork in a rotationally fixed manner, which spring arm cooperates with a spring catch on the guide pin.

Castors of the type in question are known from the prior art. For example, WO98/42523 shows and describes a castor in which a force-dependent fixed castor function is achieved by arranging two bow springs that act radially inwards in relation to the guide pin and that interact with a locking plate that has flattened areas and is connected to the guide pin in a rotationally fixed manner. The bow springs that form spring arms are attached to the fork and can thus pivot relative to the guide pin and the locking plate.

In view of the previously described prior art, a technical problem of the invention is seen in the design of a swivel castor of the type in question that is simpler in terms of production technology and more stable in use.

This problem is solved first and foremost by the subject matter of claim 1, whereby the spring arm is formed on a disc-like component separate from the fork and extends at least over an angle of 80° in the circumferential direction. As a result of this inventive design, the spring arm and at the same time the spring catch interacting with it can be positioned in a hidden position inside the fork, i.e. enclosed by the fork sleeve that can be pivoted around the guide pin. The catch mechanism is thus advantageously protected from dirt and external influences. By means of the VGN 265 098 24192DE mue/pa/g October 15, 2001

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With the proposed catch, the swivel castor, which acts in the usual way, can be used as a fixed castor at least in a predetermined swivel position. In this predetermined position, the spring arm engages in the spring catch, which is connected to the guide pin in a rotationally fixed manner. This direction locking can be canceled depending on the force. The disk-like component carrying the spring arm is arranged transversely to the direction of extension of the guide pin, preferably penetrated by the latter, with the spring catch preferably being designed in the form of a radially aligned, notch-like depression for receiving an engagement end of the spring arm. The spring catch can be formed directly on the guide pin. However, a design is preferred in which a sleeve having the spring catch is placed on the guide pin and connected to it in a rotationally fixed manner. A design in which the spring arm formed in the plane of the disk-like component is formed in one piece with this component has proven to be particularly advantageous in terms of production and assembly. It is also proposed that two spring arms are provided, which preferably interact with two correspondingly arranged spring catches on the guide pin. Even with an arrangement of two spring arms, an extension in the circumferential direction is provided at least over an angle of 80°, for example over an angle of approx. 90° or over a larger angle up to 160°, for example. The arrangement of the two spring arms can be selected so that they extend in opposite directions in the circumferential direction, with the spring arm roots being arranged next to one another. Alternatively, these two spring arms extending in opposite directions can also have a common spring arm root. As a further alternative, it is proposed that the two spring arms extend in the same direction in the circumferential direction, with the spring arm roots being arranged opposite one another. In an advantageous development of the subject matter of the invention, it is provided that the disk-like component is held in a form-fitting manner in the fork, preferably in the area of the fork sleeve surrounding the guide pin. This allows the disk-like component to be radially deformed. VGN 265 098 24192DE mue/pa/g 15. O ctober 2001

have protruding projections which engage in correspondingly arranged, window-like recesses in the fork. It is also preferred that the engagement ends of the spring arms are arranged opposite one another, so that the fork carrying the wheel is actively secured in every 180° position, in which position the castor forms a fixed castor. This locking is not brought about manually, as is known with castors, by operating a lever or the like. Rather, this locked position is brought about automatically as soon as the fork reaches the corresponding position. The directional release of the locked castor is force-dependent. An advantageous development of the subject matter of the invention provides that the disk-shaped component is a stamped sheet metal part.

The invention further relates to a swivel castor according to the features of the preamble of claim 1. In order to specify a swivel castor of the type in question, which is particularly designed to be more cost-effective in terms of production and use, it is proposed that the spring arm is arranged in a spring-loaded manner in the axial direction of the guide pin and that a locking formation that is open in the axial direction is formed on the guide pin for interaction with a counter-lock on the spring arm. This active locking mechanism is preferably arranged in a hidden position inside the fork, i.e. in the area of the fork sleeve that surrounds the guide pin, and is thus protected from dirt and external interference. As the fork carrying the wheel pivots around the guide pin, the spring arm, which is connected to the fork in a rotationally fixed manner, engages in the open locking formation of the guide pin in a predetermined pivot position. This blocking position can be canceled depending on the force, so that the fork can be pivoted further when a predetermined force (the spring force) is exceeded. In the locking position, the steering roller takes on the function of a fixed roller. In a preferred embodiment of the subject matter of the invention, the spring arm is mounted on a component which surrounds the guide pin in a ring . VGN 265 098 24192DE mue/pa/g 15 October 2001 :·.:·· ."::"! ·: ·: :'.: :"iY""y I j 1

is formed. In this regard, it is further provided that the ring-shaped component is designed as a flat part, with the counter-latch being bent out. A design in which two spring arms with opposing counter-latches are provided, so that the pivoting fork can be locked in any 180° position, has proven to be particularly advantageous. A design in which the ring-shaped component has two opposing locking tongues for positive retention in the fork, which has corresponding, window-like recesses for the locking tongues to pass through, has proven to be particularly simple in terms of production and assembly. A further advantage arises from a design in which the locking formation is formed on a component that is separate from the guide pin but is secured to it in a rotationally fixed manner. In this regard, it is further proposed that the separate component is ring-shaped and has two opposing locking formations. The components that enable active locking can be manufactured in a simple manner if the ring-shaped component and/or the separate component is designed as a stamped/bent part.

Irrespective of the inventive design according to claim 1 or claim 11, the active locking of the fork is also conceivable in connection with a conventional, manually induced fixing of the fork and the roller.

The invention is explained in more detail below with reference to the accompanying drawings, which show only three exemplary embodiments. It shows:

Fig. 1 is a view of a swivel castor according to the invention in a first embodiment;

VGN 265 098 24192DE mue/pa/g October 15, 2001

Fig. 2 shows the section along the line II-II in Fig. 1, concerning the locking position of the fork;

Fig. 3 is a sectional view corresponding to Fig. 2 with the locking mechanism removed;

Fig. 4 is a sectional view according to Fig. 2, but relating to a second embodiment;

Fig. 5 is a schematic longitudinal section through a locking arrangement, relating to a third embodiment in the locking position;

Fig. 6 shows the cross-section along the line VI-VI in Fig. 5;

Fig. 7 is a sectional view corresponding to Fig. 5, but concerning a pivoting position of the fork with the locking mechanism released.

Shown and described firstly with reference to Fig. 1 is a castor 1 which can be assigned, for example, to a hospital bed, the latter having, for example, a central control device via which the blocking of the running mobility of the castor wheel 2 and/or the pivoting mobility of the fork 3 is selectively effected.

For this purpose, a sleeve 4 is provided in a known manner which can be inserted in a rotationally fixed manner into a hollow base of a chassis, for example a bed frame, in which a plunger 5 is arranged so as to be axially movable on the rotation axis x of the castor 1. The latter is held in a raised position by a spring (not shown).

VGN 265 098 24192DE mue/pa/e October 15, 2001

Furthermore, a braking device 6 which is also held in a raised position by a spring (not shown) is accommodated in a vertically displaceable manner in the fork 3 or in the fork sleeve 3" carrying the fork legs 3'.

On the upper side, this braking device 6 is provided with a gear ring 7 arranged coaxially to the axis of rotation &khgr;, for interaction with a counter gear ring 8, which is also arranged coaxially to the axis of rotation &khgr; on the underside of the plunger 5 and is connected to it in a rotationally fixed manner.

The two gear rings are vertically spaced from each other in a basic position as shown in Fig. 1.

In a known manner, a vertical downward displacement of the tappet 5 can be carried out via a control cam 9 (not shown in detail), whereby an engagement of the two gear rings 7 and 8 is initially achieved. Due to the rotationally fixed arrangement of the gear ring 7 or the braking device 6 supporting it in the fork 3, this results in the fork 3 being pivotally fixed in the pivoting position that exists at that moment. By further downward displacement of the tappet 5, which can also be brought about manually, the braking device 6 is simultaneously displaced vertically downwards, whereby the braking surface of the braking device 6 comes into contact with the running surface 2' of the running wheel 2 to block the running mobility of the same.

In order to provide improved straight-line running properties, the swivel castor 1 is provided with a further locking device which acts automatically.

Thus, in a first embodiment according to Figs. 1 to 3, a disk-like component 10 is arranged in a rotationally fixed manner in the fork 3, in the area of the fork sleeve 3". The latter is preferably a stamped sheet metal part and has a positive holding VGN 265 098 24192DE mue/pa/g 15. O ctober 2001

The fork 3 has four radially projecting tongues 11 that are evenly distributed around the circumference. These pass through correspondingly arranged and dimensioned, window-like openings 12 in the fork sleeve 3".

The thickness of the disc-like component 10 extending transversely to the axis of rotation x of the castor 1 is approximately 1 to 3 mm.

Two spring arms 13 extending in the plane of the disc-like component 10 are punched out of this disc-like component 10. The arrangement of the two spring arms 13 is selected such that their spring arm roots are arranged next to each other in the area of a tongue 11. Starting from these spring arm roots 14, the two spring arms 13 extend in opposite directions over an angle of approximately 80° in the circumferential direction, with engagement ends 15 pointing approximately radially inwards being formed on the free ends of the spring arms 13. The length of the spring arms 13 or the angular extent in the circumferential direction thereof is selected such that the engagement ends 15 are arranged opposite one another.

The spring arms 13 interact with spring catches 16 arranged opposite one another in relation to the rotation axis x, which in the embodiment shown are formed in a notch-like manner on the outside of a spring catch sleeve 17, the spring catch sleeve 17 being held in a rotationally fixed manner on a guide pin 18 having an axially aligned guide bore 18' for the tappet 5. For the manual pivoting and wheel fixing, the tappet 5, which is otherwise rotationally fixedly connected to the guide pin 18, can be moved vertically in the guide pin 18.

The spring locking sleeve 17 penetrates the disk-like component 10 in the area of a correspondingly dimensioned central bore 19, the bore wall of which is partly defined by the disk-like component 10 itself and further by VGN 265 098 24192DE mue/pa/g 15. O ctober 2001

the radially inward-facing wall surfaces of the spring arms 13. Consequently, the radii of curvature of the spring arms 13 are adapted to the outer radius of the spring locking sleeve 17.

As a result of this inventive design, active locking of the fork 3 is possible in every 180° position, after which the swivel castor 1 takes on the function of a fixed castor. The release of the swivel direction is force-dependent. As soon as a force acting in the swivel direction of the fork 3 is greater than the spring force of the spring arms 13, the locking is canceled according to Fig. 2, whereby the engagement ends 15 are forced out of the spring catches 16 and the spring arms 13 accordingly move radially outwards into the area of correspondingly punched-out swivel spaces 20. The fork 3 can then be freely swiveled until the next 180° position is reached. In this case, the engagement ends 15 slide on the outer surface of the spring catch sleeve 17 (see Fig. 3).

An alternative design of the disk-like component, in particular the punched-out spring arms 13, is shown in Fig. 4. Here, the spring arm roots 14 of the spring arms 13 are arranged opposite one another. Accordingly, the spring arms 13 extend in the same direction in the circumferential direction over an angle of approximately 160° in the circumferential direction, so that in this embodiment too, the engagement ends 15 of the two spring arms 13 are opposite one another. The function corresponds to that of the previously described embodiment.

Figures 5 to 7 show a third embodiment in which the locking device according to the invention takes place in the axial direction.

An annular component 21 is provided in the fork sleeve 3" in a rotationally fixed manner and is designed as a flat part, which, like the previously described embodiments, is aligned transversely to the axis of rotation &khgr;.

VGN 265 098 24192DE mue/pa/e October 15, 2001

The thickness of this ring-shaped component 21 is approximately 0.5 to 1 mm. For positive retention in the fork 3 or the fork sleeve 3", the ring-shaped component 21 has two opposing locking tongues 22, which penetrate appropriately positioned and dimensioned, window-like openings 12 in the fork 3.

In the middle of the ring sections of the component 21 that extend between the locking tongues 22 and form spring arms, a counter-latch 23 is bent out for the latching engagement of a latch formation 24 that is connected in a rotationally fixed manner to the guide pin 18 that surrounds the component 21 in a ring. In accordance with the opposing arrangement of the counter-latches 23, two oppositely arranged latch formations 24 are also provided. These are formed on a component that is separate from the guide pin 18 but is secured to it in a rotationally fixed manner. This separate component 25 is ring-shaped, surrounding the guide pin 18, and in the embodiment shown is positioned parallel to and above the plane in which the ring-shaped component 21 extends.

The locking formations 24 are pressed out of the separate, likewise ring-shaped component 25.

The annular component 21 and/or the separate component 25 is designed as a stamped/bent part.

The mode of operation essentially corresponds to that of the previously described embodiments. However, in this case, with a force-dependent directional release, the spring arms 13 formed by the annular component 21 bend in the axial direction (see Fig. 7).

VGN 265 098 24192DE mue/pa/g October 15, 2001

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This design also features automatic locking in every 180° position, so that the swivel castor can take on the function of a fixed castor without manual intervention, e.g. by operating a lever or the like.

All disclosed features are (in themselves) essential to the invention. The disclosure content of the associated/attached priority documents (copy of the prior application) is hereby fully included in the disclosure of the application, also for the purpose of including features of these documents in the claims of the present application.

VGN 265 098 24192DE mue/pa/g October 15, 2001

Claims (18)

1. Castor wheel ( 1 ) with a wheel ( 2 ), a fork ( 3 ) and a guide pin ( 18 ), the fork ( 3 ) being pivotable relative to the guide pin ( 18 ) and a spring arm ( 13 ) being attached to the fork ( 3 ) in a rotationally fixed manner, which spring arm cooperates with a spring catch ( 16 ) on the guide pin ( 18 ), characterized in that the spring arm ( 13 ) is formed on a disk-like component ( 10 ) separate from the fork ( 3 ) and extends at least over an angle of 80° in the circumferential direction. 2. Castor according to claim 1 or in particular according thereto, characterized in that the spring arm ( 13 ) formed in the plane of the disc-like component ( 10 ) is formed in one piece with this component ( 10 ). 3. Castor according to one or more of the preceding claims, characterized in that two spring arms ( 13 ) are provided. 4. Castor according to one or more of the preceding claims, characterized in that two spring arms ( 13 ) extend in opposite directions in the circumferential direction. 5. Castor according to one or more of the preceding claims, characterized in that the spring arm roots ( 14 ) are arranged next to one another. 6. Castor according to one or more of the preceding claims, characterized in that the two spring arms ( 13 ) extend in the same direction in the circumferential direction. 7. Castor according to one or more of the preceding claims, characterized in that the spring arm roots ( 14 ) are arranged opposite one another. 8. Castor according to one or more of the preceding claims, characterized in that the disc-like component ( 10 ) is held in a form-fitting manner in the fork ( 3 ). 9. Castor according to one or more of the preceding claims, characterized in that the engagement ends ( 15 ) of the spring arms ( 13 ) are arranged opposite one another. 10. Castor according to one or more of the preceding claims, characterized in that the disc-shaped component ( 10 ) is a stamped sheet metal part. 11. Castor wheel ( 1 ) according to the features of the preamble of claim 1, characterized in that the spring arm ( 13 ) is arranged in a spring-loaded manner in the axial direction of the guide pin ( 18 ) and that a locking formation ( 24 ) open in the axial direction is formed on the guide pin ( 18 ) for cooperation with a counter-lock ( 23 ) on the spring arm ( 13 ). 12. Castor according to claim 11 or in particular according thereto, characterized in that the spring arm ( 13 ) is formed on a component ( 21 ) which surrounds the guide pin ( 18 ) in an annular manner. 13. Castor according to one or more of claims 11 to 12 or in particular according thereto, characterized in that the annular component ( 10 ) is designed as a flat part, wherein the counter-latch ( 23 ) is bent out. 14. Castor according to one or more of claims 11 to 13 or in particular according thereto, characterized in that two spring arms ( 13 ) with opposing counter-latches ( 23 ) are provided. 15. Castor according to one or more of claims 11 to 14 or in particular according thereto, characterized in that the annular component ( 21 ) has two opposing locking tongues ( 22 ) for positive retention in the fork ( 3 ). 16. Castor according to one or more of claims 11 to 15 or in particular according thereto, characterized in that the locking formation ( 24 ) is formed on a component ( 25 ) which is separate from the guide pin ( 18 ) but secured thereto in a rotationally fixed manner. 17. Castor according to one or more of claims 11 to 16 or in particular according thereto, characterized in that the separate component ( 25 ) is annular and has two opposing locking formations ( 24 ). 18. Castor according to one or more of claims 11 to 17 or in particular according thereto, characterized in that the annular component ( 21 ) and/or the separate component ( 25 ) is designed as a stamped/bent part.