GB2091090A

GB2091090A - Castors

Info

Publication number: GB2091090A
Application number: GB8118438A
Authority: GB
Original assignee: TREVINI OGTM
Current assignee: TREVINI OGTM
Priority date: 1980-06-26
Filing date: 1981-06-16
Publication date: 1982-07-28
Also published as: IT8022139V0; DE8117896U1; FR2485448A1

Abstract

There is disclosed a castor assembly comprising a central supporting body having a downwardly opening bore and a transverse cradle at the lower end of the base; a T shaped axle piece with its stem slidably housed in the bore and the arms thereof in the cradle; a wheel rotatably coupled to each arm; a coil spring in the bore acting on the stem for pushing the hubs of the wheels against braking fins extending from the cradle housing when no compressive load is applied, but releasing the wheels when loaded; and a housing surrounding the wheel and supporting body and effective to conceal from view the wheels and to engage with a peripheral edge against the wheels to prevent these latter from axially disengaging from the axle piece. <IMAGE>

Description

SPECIFICATION Pirouetting wheel, provided with an automatic locking device The present invention relates to a pirouetting wheel structure, for example, a swivel castor, provided with an automatic locking device.

As it is known, pirouetting wheels provided with an automatic locking device are wheels effective to be applied to chairs, armchairs and the like, and they are automatically locked as on the chair or the like there is no person, while being able of permitting tlzo wheels to freely rotate as a weight, possibly presettable, acts on said wheels.

The presently known pirouetting wheels of the aforesaid type are generally rather intricate, both due to the need of preventing the wheels from axially sliding and due to the fact that the automatic locking device, that is the device effective to brake the wheel, in the absence of a weight thereon, is generally formed buy a high number of component parts.

Another drawback of the aforesaid type of pirnuet- ting wheel is that, because of the need of assembiying a great number of component parts, the assem- blying time is comparatively a long one and, accordingly, such as to adversely affect the cost of the wheel itself.

Thus, the task of the present invention is to eliminate the thereinabove cited drawbacks by providing a pirouetting wheel structure, provided with an automatic locking device, wherein constructional approaches are adopted effective to greatly simplify the making of the wheel itself, while providing a high quality product.

Within the thereinabove mentioned task, it is a main object of the present invention to provide a pirouetting wheel structure effective to give great guarantees of reliability and useful duration.

Yet another object of the present invention is to provide a pirouetting wheel structure, provided with an automatic locking device wherein the locking device is greatly simplified and effective to operate without jammings or damages.

The thereinabove mentioned task and objects, and yet other objects which will become more apparent thereinafter are achieved by a pirouetting wheel structure, provided with an automatic locking device, characterized in that it comprises a central body, defining a coupling housing, open toward the bottom, therein a cradle housing is formed, a tailpiece being slidably housed in said coupling housing, perpendicularly extending from a cross pin therewith a wheel pair is rotatably coupled, resilient means, acting on said tailpiece and effective to push the hub of the wheels against braking fins extending from said cradle housing, as on the chair or the like there is not any person, thereon said pirouetting wheel is mounted, and effective to permit said tailpiece to upwardly move, in orderto disengage the wheel hubs from said fins, as on the chair or the like there is no person, a housing being further provided as formed on the central body and leading to a coverring member effective to axially engage with a face of said wheels to prevent these latter from axially disengaging.

Further characteristics and advantages will become more apparent from the following detailed description of a pirouetting wheel, provided with an automatic locking device, and being illustrated by way of an indicative but not limitative example in the accompanying drawing, where: fig. 1 is a perspective view illustrating the pirouetting wheel according to the present invention; fig. 2 illustrates a cross-section view of the pirouetting wheel; fig. 3 is an exploded view illustrating the central body, with the cross pin, thereto the wheels are applied; and fig. 4 illustrates the central body as seen from another side, with respect to that iIlust;ted in fig. 3.

With reference to the numbers of the aforesaid fig urns, the pirouetting wheel structure, being indicated generally at (t ), comprises a central body (2), therein a coupling housing (3) is formed, having a substantially vertical axis, and bsirc open down vjardlythereat it defines a cradle housing (4).

In the housing (3) a tailpiece is slidably ,f housed, indicated at (5) and psrp6ndlicularly extending from an interiediate portion o, a cross pin (6), therewith wheels 7) may be rotatably associated.

Said tailpiece (5) is effective to slide in the housing (3), in order to obtain the automatic locking of the wheels, in the absence of any weights on the chair or the like thereon the pirouetting wheel 11) ) according to the invention is mounted.

To this end, between the bottom of the housing (3) and the free end of the tailpiece (5), there are provided resilient means, advantageously consisting of a coil spring (10), acting to push, in the absence of any weights on the chair, the hub (11) of the wheels (7) against braking fins (12), extending from the end of the cradle housing (4) in a substantially perpendicular direction, with respect to the housing extension, and being substantially parallel with respctto said cross pin (6).

Furthermore, the engaging of the hubs (11) with the braking fins (12) prevents the tailpiece (5) from being pushed outwardly from the housing (3).

The central body (2) defines a housing (20), parallely extending with respect to the housing (3) and effective to rotatably engage with the pivoting pin (21), of known type, which is provided for connection with the end of a chair or the like.

The housing (20), which is open at the top thereof, leads to a covering member (30), which is made rigid with the central body (2), by suitable coupling means.

The covering member (30), in addition to provid ing for the function of covering the wheels (7), also provides the very important function of preventing said wheels (7) from axially disengaging.

Due to this reason, it has advantageously a substantially circular configuration and is provided, at the bottom or lower portion whereof, with a circular opening, located substantially at the position taken by the cross pin (6), in the absence of any weights on the chair or the like.

The circular opening engages with an axial point of a face of the wheels (7), which, suitably, are provided with a swollen portion (31), having the shape of a spherical bowl portion.

Advantageously, though not necessarily, the swollen portion (31) has a bending radius which is less than, or possibly equal to, the radius of the circular opening defined by the covering member (30), in such a way that the contact is localized to a single point.

The pirouetting wheel according to the present invention can be assembled in a very simple way: in fact firstly the spring (10) and tailpiece (5) are inserted into the seat (3); then the wheels (7) are applied in such a way that the hubs (11) are located above the fins (12).

Upon having carried out this preliminary operation, the covering member is applied, indicated at (30), which, by engaging with the wheels (7) in the thereinabove described way, prevents said wheels from axially disengaging.

The pirouetting wheel according to the present invention operates in the following manner: as no person rests on the chair thereto the pirouetting wheel (1) according to the invention is applied, the spring (10) pushes the hubs (11) ofthewheeels (7) against the braking fins (12), thereby providing a fric tion effect preventing said wheels from idly rotating and holding the chair or armchair thereto the pirouetting wheel is applied in a locked condition.

As soon as a weight rests on the chair, that is that of the person, this weight exceeds the force of the spring (10), while the talpiece upwardly slides into the housing (3), and, practically the hubs (11) move away from the braking fins (12), thereby allowing for the wheels (7) to freely rotate.

From the above description, it should be noted that the invention fully achieves the intended objects.

In particular it is to be pointed out the great con- structional simplicity of the pirouetting wheel according to the present invention, which, to the typical advantages of the automatic locking device, adds the advantage of the provision of the covering member which, in addition to protecting or concealing from view the wheels, prevents these latter from axially disengaging.

In practicing the invention, the used materials and the specific size and shape can be any, depending on the needs.

Claims

1. A pirouetting wheel structure, provided with an automatic locking device, characterized in that it comprises a central body, defining a coupling hous ing, open toward the bottom, therein a cradle hous ing is formed, a tailpiece being slidably housed in said coupling housing, perpendicularly extending f. am a cross pin therewith a wheel pair is rotatably coupled, resilient means, acting on said tailpiece and effective to push the hub of the wheels against braking fins extending from said cradle housing, as on the chair or the like there is not any person, thereon said pirouetting wheel is mounted, and effective to permit said tailpiece to upwardly move, in orderto disengage the wheel hubs from said fins, as on the chairorthe like there is a person, a housing being further provided as formed on the central body and leading to a covering member effective to axially engage with a face of said wheels to prevent these latter from axially disengaging.

2. A pirouetting wheel structure, provided with an automatic locking device, according to the preceding claim, characterized in that said resilient means consists of a coil spring effective to act between the bottom of said coupling housing or seat and the free end of said tailpiece.

3. A pirouetting wheel structure, provided with an automatic locking device, according to the preceding claims, characterized in that said braking fins extend substantially parallely with respect to the extension of said cross pin, as housed in said cradle housing.

4. A pirouetting wheel structure, provided with an automatic locking device, according to one or more of the preceding claims, characterized in that said wheels are provided on the face whereof turned outwardly, with a swollen portion, shaped as a spheric bowl portion.

5. A pirouetting wheel stucture, provided with an automatic locking device, according to one or more of the preceding claims, characterized in that said covering member has a substantially circular shape and defines, at the bottom whereof, a substantially circular opening, located at the position taken by said cross pin axis in the absence of any weights on said pirouetting wheel.

6. A pirouetting wheei structure, provided with an automatic locking device substantially as herein described with reference to and as illustrated in the accompanying drawings.