Miscellaneous hardware (e.g. – bushing – carpet fastener – caster – Casters – Locked
Reexamination Certificate
1999-07-16
2001-09-11
Knight, Anthony (Department: 3626)
Miscellaneous hardware (e.g., bushing, carpet fastener, caster,
Casters
Locked
C016S030000, C177S144000
Reexamination Certificate
active
06286183
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The invention relates to a caster, in particular for movable hospital beds, laboratory tables and the like, with a securing device which is connected to a handle via a Bowden cable.
Running or steering casters arranged on movable hospital beds, laboratory tables and the like are often secured by means of linkage-actuated brake blocks. DE 44 27 320 A1 discloses a securing device, in which a securing foot, axially displaceable within a tubular strut, can be extended in such a way that the casters lift off from the ground and, consequently, movable hospital beds, laboratory tables and the like are secured reliably. The axial displacement of the securing foot is carried out by transmitting the force, generated by means of a handle, via a Bowden cable. A feature common to both of these solutions is that a multiplicity of exposed and cooperating components, such as a brake linkage or the securing foot, are easily susceptible to contamination or considerable problems in disinfecting them arise.
SUMMARY OF THE INVENTION
It is an object of the invention to develop a caster further, in such a way that, in addition to the movable hospital bed, laboratory table or the like being secured reliably, said caster meets hygienic requirements which exceed the customary standard.
According to the invention, with the aim being that a locking piece is movable by means of the Bowden cable between a locking and an unlocking position, in the locking position, the locking piece, being located between pairs of stop faces which are fixed relative to a rotary part and are fixed on the rotary part and which are designed in relation to an axis of rotation, blocks rotational movement about the axis of rotation, and in the unlocking position, the locking piece releases at least identically fixed pairs of the stop faces for rotational movement of the rotary part. By means of the securing device according to the invention, in the first place, a running caster can be secured reliably in terms of its rotational movement. However, the securing device according to the invention also serves for securing a steering caster in terms of rotational movement about, for example, its axis of rotation parallel to the strut, namely a vertical axis. In addition to the special possibilities for using it, the securing device according to the invention affords further advantages. In the first place, only one locking piece is moved between a locking and an unlocking position by means of the Bowden cable. As a result, the actuating force required or the force to be transmitted by the Bowden cable is reduced considerably, as compared with DE 44 27 320, since, there, the entire table weight is carried via the Bowden cables. In the invention, in the locking position, the locking piece is introduced essentially positively between stop faces fixed on the rotary part and fixed relative to this rotary part, with the result that rotational movement of the rotary part about an axis of rotation is blocked. For this purpose, for example, the stop faces are arranged so as to extend essentially axially and radially in relation to the axis of rotation. At least one pair of such stop faces is to be provided on the rotary part. Likewise, a component which is fixed relative to the rotary part also has such a pair of stop faces. Such a fixed component may itself, in turn, constitute a rotary part in relation to a further component, for example a strut. In the unlocking position, the locking piece located between the at least two pairs of stop faces, when it is actuated by means of the Bowden cable, then releases the at least one pair of identically fixed stop faces for rotational movement of the rotary part, specifically either the stop faces of the rotary part or the stop faces which are fixed relative to the rotary part. If appropriate, the locking piece may also release all the stop faces. For this purpose, there may be provision for the locking piece to be mounted tiltably about an axis between one pair of stop faces and to be rotated about this tilt axis by means of the Bowden cable, until the stop faces of the other pair are released. Preferably, however, the locking piece is axially displaceable on the axis of rotation, and it is further preferred that the locking piece be axially displaceable between stop faces. As a result, complex cinematics are avoided and locking and unlocking are executed by linear displacement of the locking piece by means of the Bowden cable. The securing device according to the invention thus not only acts directly on the caster wheel, but locks an axis of the rotary part by means of its bearing receiving the latter. Consequently, the radial dimensions of the securing device as a whole can be kept small. The axial extent of the stop faces is also uncritical, since, in the securing device according to the invention, securing takes place positively, in contrast to known frictional methods of securing the, for example, caster wheel. It is therefore possible to encase the securing device completely, for example within the strut or within the caster wheel, and thus design said securing device to meet the most stringent hygiene requirements. A further advantage is the guidance of the locking piece between stop faces. Tipping or maladjustment of the locking piece is therefore ruled out. Such guiding stop faces may, in particular, be formed, so as to be fixed on the rotary part, by side faces of a long hole. A barlike locking piece can pass through this long hole, said locking piece having a radial projection which is of round or slightly wedgelike cross section, a cross-sectional taper then being directed toward the free space between the other pair of stop faces. This ensures easy engagement during the transition into the locking position. These other pairs of stop faces are then preferably formed by flanks of teeth of a toothed ring arranged concentrically to the axis of rotation. Securing can then take place in a multiplicity of positions of the rotary part, depending on the pitch of said toothed ring. Should the locking piece nevertheless strike a tooth during the securing operation, securing can still be achieved by the rotary part being slightly displaced with ease. Locking is carried out by means of a pull applied to the Bowden cable by means of the handle counter to the force of a spring. By virtue of this measure, the Bowden cable is, in general, loaded only by tensile forces. Consequently, the core of the Bowden cable can be made comparatively flexible and the handle can therefore be attached at virtually any desired location on the movable hospital bed, laboratory table or the like. In this case, it is further preferred to design the spring as a compression spring which is supported between a locking piece and a shoulder axially immovable relative to the Bowden cable. A special abutment for the spring on the Bowden cable is thereby avoided, since the locking piece has to be fixed to the latter at the factory. In a further embodiment of the invention, it is provided that a rocker carrying the caster wheel is mounted rotatably about a vertical axis by means of an insertion part in an essentially tubular strut, that a barlike locking piece fixed to the Bowden cable is axially displaceable in a long hole passing through the insertion part and projects radially from the insertion part, that an axially projecting toothed ring is designed coaxially to the vertical axis, so as to be fixed on the strut, and that, in the locking position, the portions of the locking piece which project radially from the insertion part, said portions being located between pairs of teeth of the toothed ring, block rotational movement about the vertical axis. In a steering caster of this type, therefore, in the locking position, a steering movement, that is to say rotation of the caster about the vertical axis, is ruled out. In a further embodiment, the invention provides a unilateral rocker mounting of the caster wheel on a fixed wheel shaft, through which the Bowden cable terminating in a locking piece
Engels Siegfried
Stickel Uwe
Farber Martin A.
Knight Anthony
Tente-Rollen GmbH & Co.
Williams Mark
LandOfFree
Caster with securing device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Caster with securing device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Caster with securing device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2436979