Actuating Mechanism for a Caster

Abstract

An actuating mechanism for a caster that brakes and positions the caster by means of a cam mechanism that enables braking of the caster using minimum forces developed on the brake lever or brake rod. The mechanism helps to handle casters of patient support apparatuses in hospital and nursery facilities easily, using minimum force developed by caregivers or by an electronic caster brake systems if used for braking of casters of patient support apparatuses, as well. The mechanism may produce an outstanding decrease of noise level of castors on patient support apparatuses.

Claims

1. An actuating mechanism assembly for a caster comprises a pin, a carrying member wherein an inner part of the pin comprises a cam mechanism comprising a cam for position of actuating pedal of brake pedal, a cam for direction of caster, and a cam for braking the caster and of vertical brake of caster, wherein at least one cam is in contact with at least on from three lifting members, wherein at least one lifting member is in contact with at least one from three locking levers, wherein at least one locking lever is in contact with at least one ratchet, wherein at least some lifting members or locking levers are limited by at least one spring.

2. The actuating mechanism assembly for a caster according to claim 1, wherein a cam for position of the actuating pedal is in contact with a lifting member of position of the actuating pedal of the caster which is in contact with a spring of position of the actuating pedal.

3. The actuating mechanism assembly for a caster according to claim 1, wherein a cam for position of the caster is in contact with a lifting member of direction of the caster which is in contact with a locking lever of direction of the caster bearing onto a ratchet of direction of the caster, wherein the locking lever of direction of the caster is limited by a spring of direction of the caster.

4. The actuating mechanism assembly for a caster according to claim 1, wherein a cam for braking the caster and of vertical brake of the caster is in contact with a lifting member of brake of the caster and of vertical brake of the caster and actuates a locking lever of brake of the caster and a locking lever of vertical brake of the caster.

5. The actuating mechanism assembly for a caster according to claim 4, wherein the locking lever of brake of the caster bears onto a ratchet of brake of the caster and is limited by a spring of brake of the caster.

6. The actuating mechanism assembly for a caster according to claim 4, wherein the locking lever of vertical brake of the caster bears onto a ratchet of vertical brake of the caster and is limited by a spring of vertical brake of the caster.

7. The actuating mechanism assembly for a caster according to claim 2, wherein the spring of position of the actuating pedal bears onto a backstop of the actuating pedal by means of the lifting member of position of the actuating pedal and the cam for position of the actuating pedal.

8. The actuating mechanism assembly for a caster according to claim 1, wherein the cam mechanism comprises a cylinder with inner cut, wherein at least one external part has a form of waves or protrusions which are in contact with at least one of three lifting members.

9. The actuating mechanism assembly for a caster according to claim 1, wherein the cam mechanism comprises two parts, wherein at least one part of this cam mechanism comprises the cam for position of the actuating pedal and at least one part of this cam mechanism comprises the cam for position of the caster and the cam for braking the caster and of vertical brake of the caster.

10. The actuating mechanism assembly for a caster according to claim 1, wherein the cam for braking the caster and of vertical brake of the caster is in contact with the lifting member of brake of the caster and of vertical brake of the caster and actuates the locking lever of brake of the caster bearing onto a yoke of a caster with two-way band brake.

11. The actuating mechanism assembly for a caster according to claim 1, wherein the cam mechanism comprises two parts, wherein the first part comprises a cylinder whose at least one part comprises toothing.

12. The actuating mechanism assembly for a caster according to claim 11, wherein the cam mechanism comprises two parts, wherein the second part fits into a middle part of the first part of the cylinder and the opposite side comprises two waves.

Description

LIST OF DRAWINGS

[0027] FIG. 1 shows side elevation of a caster with internal toothing and a pin attached to the carrying member (e.g. fork).

[0028] FIG. 2 shows axonometric projection of a caster with internal toothing, a carrying member (e.g. fork) and a part of a cam mechanism in detail drawing.

[0029] FIG. 3 shows axonometric projection of a cam mechanism.

[0030] FIG. 4 shows side elevation of part of a cam mechanism and an internal actuating of a brake system of a caster with internal toothing that is located in the pin.

[0031] FIG. 5 shows axonometric projection of internal arrangement of a cam mechanism with a brake system of a caster with internal toothing.

[0032] FIG. 6 shows kinetic scheme of an internal arrangement of a caster with internal toothing.

[0033] FIG. 7 shows side elevation of a brake system of a caster with a band brake, a pin and a lever.

EXEMPLARY EMBODIMENTS OF THE INVENTION

[0034] The FIG. 1 shows a caster 4 with internal toothing 1, preferably such caster can be used with wheeled equipment as e.g. trolleys, stretchers, patient support apparatuses, beds, tables, bedside tables, bars and similar types of furniture that need to be transported from one place A to another place B.

[0035] The FIG. 1 shows side elevation of a caster 4 with internal toothing 15, which is fixed to a carrying member 3 (e.g. fork) in the middle of the caster through opening 13 by means of fixing pin 14 (not shown). The fixing pin 14 for fixing the caster 4 in the carrying member 3 may be in form of a screw, rivet or any other types of pins. The carrying member 3 with vertical axis of rotation continues with bearing 5, which is attached to a pin 2. The side elevation of the pin 2 shows hexagonal opening 16 for fixing the actuating pedal 1 (not shown). This opening 16 is also opening for a cam mechanism 6. In another embodiment, a caster with two-way band brake 17 can be fixed to the carrying member 3 through opening 13 for fixing of the caster by means of fixing pin 14, see the FIG. 7 for details.

[0036] The presented solution discloses cam mechanism 6 comprising the same hexagonal opening 16 as other standard known types of simple cams. The presented cam mechanism 6 comprises a cam for position of the actuating pedal 6a, a cam for direction of the caster 6b and a cam for braking the caster and of vertical brake of caster 6c. Due to using of this cam mechanism 6 the overall braking system of the caster 4 reaches better qualities upon smaller demands on developing forces and smaller friction forces.

[0037] The FIG. 2 shows axonometric projection of a caster 4 in detailed drawing showing the caster 4 with internal toothing 15 comprising three locking levers 9: locking lever of direction of the caster 9b, locking lever of brake of the caster 9c and locking lever of vertical brake of the caster 9d, which are located under the cover of a carrying member 3 and a bearing 5 that continues a pin 2, in which the entire cam mechanism 6 is located (shown partially). The cam mechanism 6 comprises a cam for position of the actuating pedal 6a, a cam for direction of the caster 6b and a cam for braking the caster and of vertical brake of the caster 6c. The FIG. 2 also shows the carrying member 3 comprising an opening 13 for fixing of the caster, a ratchet of direction of the caster 10b, above which a mechanism of interlocking lifting members 8a, 8b and 8c (not shown) is located inside the pin 2. The bearing 5 is located above the ratchet of direction of the caster 10b and the pin 2 for fixing the caster to the frame of the patient support apparatus and attaching an actuating pedal 1 (not shown) is located above the bearing 5. The cam mechanism 6 is located in the upper part of the pin 2, however, to clarify the structure the cam mechanism 6 is disclosed separately in FIG. 3.

[0038] The FIG. 3 shows axonometric projection of a cam mechanism 6 located in the upper part of a pin 2 of a caster 4 and being a part of the inner actuating mechanism that actuates all positions of the caster 4; rotation of the caster 4 around vertical and horizontal rotation axis, braking and direction of travel. The FIG. 3 shows that the cam mechanism 6 has a shape of a cylinder, which is hollow inside, comprising an opening which is an opening for the actuating pedal 16, in parallel, and has a hexagon shape. For better view the cam mechanism 6 is turned with bottom side upwards so that the individual parts of the cam mechanism 6 could be visible.

[0039] The cam mechanism 6 is divided into two parts for better assembly of the cam mechanism 6 into the pin 2. The first part is a cylinder with at least one side in a form of toothing which creates actuating part of the cam for position of the actuating pedal 6a. The second part fits in the middle part of the cylinder of the cam for position of the actuating pedal 6a, which is rectangular cut out so that the second part could set on the cylinder part of the cam for position of the actuating pedal 6a to create one component—i.e. the cam mechanism 6. The second part has a shape of two external waves and one internal wave. The FIG. 3 shows the waves in axonometric projection to be visible from above. Two external waves form the cam for braking the caster and of the vertical brake of the caster 6c, the internal wave forms the cam for direction of the caster 6b. In another embodiment, the second part of the cam mechanism 6 comprises different shapes of toothing. Optionally, the cam mechanism 6 may be produced from one piece of plastic material or metal or metal alloys.

[0040] The FIG. 4 shows assembly of caster 4 comprising a pin 2 (not shown), a bearing 5 (not shown) and a carrying member 3 (not shown). The FIG. 4 shows a partial internal structure of the pin 2 which comprises a cam mechanism 6, wherein the FIG. 4 shows a cam for direction of caster 6b comprising an internal wave of the cam mechanism 6, a cam for braking the caster and of vertical brake of the caster 6c comprising external waves of the cam mechanism 6. The cam mechanism 6 is in contact with lifting members 8, wherein the FIG. 4 shows a lifting member of direction of the caster 8b and a lifting member of brake of the caster and of vertical brake of the caster 8c. In addition, the pin 2 further comprises a spring of position of the actuating pedal 11a, which is in contact with a lifting member of position of the actuating pedal 8a, which is shown in the FIG. 5. In parallel, the spring of position of the actuating pedal 11a is in contact with the pin 2 at one end and at another end with the lifting member of position of the actuating pedal 8a (not shown). A ratchet of vertical brake of the caster 10d comprises a ring gear having toothing at the bottom edge which engages teeth of a locking lever of vertical brake of the caster 9d and of a locking lever of direction of the caster 9b. The locking lever of vertical brake of the caster 9d and the locking lever of direction of the caster 9b are interlocked at least at one point, wherein they are in parallel in contact with the third locking lever of brake of the caster 9c at this point. A ratchet of brake of the caster 10c engages the locking lever of brake of the caster 9c, wherein this ratchet of brake of the caster 10c is an internal toothing 15 of the caster.

[0041] The FIG. 5 shows axonometric projection of a part of the internal arrangement of a cam mechanism 6 with actuating mechanism of the caster 4. The FIG. 5 shows only that part of the cam mechanism 6, which actuates the position of the actuating pedal, i.e. a cam for position of the actuating pedal 6a, which bears on a toothed lifting member of position of the actuating pedal 6a, having shape of a rook (a toothed tower). The lifting member of position of the actuating pedal 8a comprises other two interlocked lifting members, i.e. lifting member of direction of the caster 8b and a lifting member of brake of the caster and of vertical brake of the caster 8c (not shown). The cam for position of the actuating pedal 6a and the lifting member of position of the actuating pedal 8a are in contact and continue a backstop of the actual pedal 12 (not shown here). A spring of position of the actuating pedal 11a is in contact with the lifting member of position of the actuating pedal 8a. All lifting members 8 are interlocked and are in contact with the cam mechanism 6, i.e. the cam for position 6a, the cam for direction 6b and the cam for braking and of vertical brake 6c of the caster. All lifting members 8, i.e. lifting members 8a, 8b and 8c are located in the pin 2 coaxially. A ratchet of vertical brake of the caster 10d comprises a ring gear having toothing at the bottom edge which engages teeth of a locking lever of vertical brake of the caster 9d and of a locking lever of direction of the caster 9b. A ratchet of brake of the caster 10c engages the locking lever of brake of the caster 9c, wherein this ratchet of brake of the caster 10c is an internal toothing 15 of the caster.

[0042] The FIG. 6 shows kinematic scheme of the entire cam mechanism 6. The FIG. 6 shows three independent cams of the cam mechanism 6 which actuates the individual positions of a caster 4. The FIG. 6 shows cross section of a pin 2 in which a cam for position of the actuating pedal 6a, a cam for direction of the caster 6b and a cam for braking and of vertical brake of the caster 6c are located. The pin 2 comprises also mutually interlocked lifting members 8 such that a lifting member of position of the actuating pedal a is in contact with the cam for position of the actuating pedal 6a a lifting member of direction of the caster 8b is in contact with the cam for direction of the caster 6b and a lifting member of brake and of vertical brake of the caster 8c is in contact with the cam for braking and of vertical brake of the caster 6c. The FIG. 6 obviously shows that the pin 2 continues with a carrying member 3 and a bearing 5 is located between the carrying member 3 and the pin 2. The caster 4 with internal toothing is attached to the carrying member 3, wherein the toothing of the caster is in parallel a ratchet of brake of the caster 10c. In another embodiment, a caster with two-way band brake 17 can be attached to the carrying member 3.

[0043] The first cam for position of the actuating pedal 6a is actuated by the lifting member of position of the actuating pedal 8a, under which a spring of position of the actuating pedal 11a is located. The spring of position of the actuating pedal 11a lifts the lifting member of position of the actuating pedal 8a, which bears on the cam for position of the actuating pedal 6a and locks the position of the actuating pedal 1 (not shown). The cam for position of the actuating pedal 6a also bears on a backstop of the actuating pedal 12 at edge positions. The backstop of the actuating pedal 12 is located above the cam mechanism 6 in the pin 2, by which position of the actuating pedal 1 is limited (not shown). The second cam for direction of the caster 6b actuates a locking lever of direction of the caster 9b by means of a lifting member of direction of the caster 8b. The locking lever of direction of the caster 9b is in contact with a pivot 7 and the distance between the locked and released position of the ratchet of direction of the caster 10p, i.e. locked and released mode of direction of the caster, is limited by a spring of direction of the caster 11b, which is located under the locking lever of direction of the caster 9b. The third cam for braking and of vertical brake of the caster 6c actuates the locking lever of brake of the caster 9c and the locking lever of vertical brake of the caster 9d by means of lifting member of brake and of vertical brake of the caster 8c. Both these levers 9c and 9d are in contact with the pivot 7 where the locking lever of vertical brake of the caster 9d is in level with the pivot 7, same as the locking lever of direction of the caster 9b wherein the locking lever of vertical brake of the caster 9d is limited by a spring of vertical brake of the caster 11d. The locking lever of brake of the caster 9c is in contact with the pivot 7, the lever 9c is limited by a spring of brake of the caster 11c.

[0044] The FIG. 7 shows braking mechanism shown as side elevation. The FIG. 7 shows a pin 2 which comprises a cam mechanism 6 which comprises a cam for position of the actuating pedal 6a, a cam for direction of the caster 6b and a cam for braking and of vertical brake of the caster 6c The internal arrangement of the pin 2 is the same as in all preceding figures. A bearing 5 is fixed to the pin 2 and under the bearing 5 there is located a carrying member 2 having a cover in which locking levers 9 are located, i.e. a locking lever of direction of the caster 9b, a locking lever of brake of the caster 9c and a locking lever of vertical brake of the caster 9d. A caster with two-way band brake 17 is fixed to the carrying member 3. The internal part of the caster with two-way band brake 17 comprises a inner brake drum 18, a yoke 19 with anchoring points 21 to fix a brake band 20, a band brake 20, which is fixed to the anchoring points 21 of the yoke 19 by lugs 22. The locking lever of brake of the caster 9c bears on the yoke 19 the lever is actuated by a cam for braking and of vertical brake of the caster 6c. When the locking lever of brake of the caster 9c bears on the yoke 19, the brake band 20 around the brake drum 18 is released by which the caster with two-way band brake 17 is released. In such case, the yoke 19 is in one plane with rotation axis and the caster with two-way band brake 17 is released.

[0045] Braking of the caster with two-way band brake 17 occurs at the moment, when the locking lever of brake of the caster 9c releases its pressure on the yoke 19, by which position of the yoke 19 changes. Release of lever force developed on the yoke 19 causes change of position by means of spring member 25 under yoke (not shown), due to which the brake band 20 shrinks around the brake drum 18 of the caster with two-way band brake 17. When the caster moves in the first phase, the spring member 25 under the yoke does not develop sufficient force to brake the brake drum 18 of the caster. At the moment locking lever of brake of the caster 9c is released onto the yoke 19, the yoke 19 leans and bears on the guiding bar 23 of the yoke according to direction of rotation of the caster with two-way band brake 17, and thus force is developed which consequently shrinks the brake band 20 around the brake drum 18 which brakes the caster with two-way band brake 17. Change of position of the yoke 19 is enabled by symmetry of the yoke 19 therewith that the yoke 19 changes position into the opposite direction of ride. By changing position of the yoke 19 into the opposite side, the brake drum 18 of the caster with two-way band brake 17 may be braked even during opposite direction of ride.

LIST OF REFERENCES

[0046] 1) Brake pedal (of a caster) (not shown) [0047] 2) Pin [0048] 3) Fork (carrying member) [0049] 4) Caster (with internal toothing) [0050] 5) Bearing [0051] 6) Cam mechanism [0052] 6a) cam for position of actuating pedal [0053] 6b) cam for direction of caster [0054] 6c) cam for braking the caster and of vertical brake of caster [0055] 7) Pivot [0056] 8) Lifting member [0057] 8a) lifting member of position of actuating pedal [0058] 8b) lifting member of direction of caster [0059] 8c) lifting member of brake of caster and of vertical brake of caster [0060] 9) Locking lever [0061] 9b) locking lever of direction of caster [0062] 9c) locking lever of brake of caster [0063] 9d) locking lever of vertical brake of caster [0064] 10) Ratchet (ratchet-wheel) [0065] 10b) ratchet of direction of caster [0066] 10c) ratchet of brake of caster [0067] 10d) ratchet of vertical brake of caster [0068] 11) Spring [0069] 11a) spring of position of actuating pedal [0070] 11b) spring of direction of caster [0071] 11c) spring of brake of caster [0072] 11d) spring of vertical brake of caster [0073] 12) Backstop (of actuating pedal) [0074] 13) Opening (for fixing a caster) [0075] 14) Fixing pin (of a caster)—not shown [0076] 15) Internal toothing (of a caster) [0077] 16) Opening for actuating pedal [0078] 17) Caster with a two-way band brake [0079] 18) Brake drum [0080] 19) Yoke [0081] 20) Brake band (of a two-way band brake) [0082] 21) Anchoring point (a, b, c, d) [0083] 22) Lug (for fixing of a brake band) [0084] 23) Guiding bar of a yoke (with two openings) [0085] 24) Yoke support (not shown) [0086] 25) Spring member under yoke (not shown) [0087] 26) Yoke arms (not shown)