GB2060371A

GB2060371A - Bearing frame, for example, a stretcher bearing frame

Info

Publication number: GB2060371A
Application number: GB8028950A
Authority: GB
Original assignee: Binz GmbH and Co
Current assignee: Binz GmbH and Co
Priority date: 1979-09-11
Filing date: 1980-09-08
Publication date: 1981-05-07
Also published as: FR2464705B1; ATA445180A; GB2060371B; AT369259B; DE2936617A1; FR2464705A1; DE2936617C2

Abstract

A bearing frame, for example, a stretcher bearing frame, comprises a pivotally mounted support (11) and a pneumatic spring suspension (20). The pressure or volume of gas in the suspension is automatically regulated in dependence upon the load on the support so that the support is substantially in a predetermined datum position irrespective of the load thereon. <IMAGE>

Description

SPECIFICATION Bearing frame, for example, a stretcher bearing frame This invention relates to bearing frames and in particular, although not so restricted to stretcher bearing frames.

There are known stretcher bearing frames, in which the firmness of a mechanical spring suspen sion supporting the stretcher bearing frame can be varied, for example by modifying the effective lever arm. Thus the characteristics of the spring suspension may be adapted to varying load, for example, the weight of different patients. In such known stretcher bearing frames adjustment is effected manually.

The present invention seeks to provide, amongst other things, a stretcher bearing frame having a suspension means which can adapt to the different loads on a stretcher bearing frame in a simple and effective manner, while at the same time facilitating the work of operating personnel.

According to the present invention there is provided a bearing frame including: pivotably mounted support means; adjustable pneumatic spring suspension means; and adjusting means for automatically regulating the pressure or volume of gas in said suspension means in dependence upon the load on the support means so that the support means is substantially in a predetermined datum position irrespective of the load on the support means.

In the case of a stretcher bearing frame the suspension means, for example, permits a knock-free springing which is particularly comfortable for a patient and which reacts to variations in load with a friction-free action. Operating personnel do not need to set spring temper or preset the spring pressure as with known stretcher bearing frames and can therefore devote their time to their other duties, in particular attending to the patient.

The invention is illustrated, merely by way of example, in the accompanying drawing which shows schematically a stretcher bearing frame according to the present invention.

A stretcher bearing frame 11 is resiliently mounted on a floor 10, e.g. the floor of an ambulance. The stretcher bearing frame 11 consists of a framework 12, two side supports 13 which are in the form of U-shaped rails, and a stretcher bearing slide 14 slidably guided for movement in the longitudinal direction by rollers 15 engaged by the side supports 13.

The slide 14 serves to receive a stretcher 16 which, in turn, either rests on longitudinal rails of the slide by means of rollers 17 or can be moved in the longitudinal direction of the slide. Locking devices (not shown) secure the stretcher 16 on the slide 14to prevent unintentional longitudinal displacement thereof.

The framework 12 and therefore the entire stretcher bearing frame 11 is pivotably mounted at its rear end, that is, when used in an ambulance in the area of the rear door of an ambulance, on a joint 18, having a horizontal transverse axis mounted on the floor 10 and, at its front end, is guided for move ment in the vertical direction and prevented from moving transversely by a scissor-type system 19, which is formed, for example, by two pairs of arms mounted on either side of the vertical median plane of the stretcher bearing frame.

Serving as springing for the stretcher bearing frame is a pneumatic spring suspension 20 which can comprise, for example, one or more spring diaphragms in an air cylinder, one or more pistons sliding in respective cylinders or one or more pneumatic spring elements. The suspension 20 is attached, for example, to a stand 21 mounted on the floor 10. A plunger 22, connected to a movable part (or parts) of the suspension, transmits motion thereof to the framework 12 and to the entire stretcher bearing frame 11 in such a way that the latter pivots upwards or downwards about the joint 18.

The suspension 20 receives a pneumatic pressure medium via a supply line having an adjustable throttle 23 therein from a pressure reservoir 24 upstream of the suspension. The pressure reservoir 24 in turn receives pneumatic pressure medium via lines 25, 26, 27, a control valve 28 being disposed between the lines 25, 26. The control valve 28, which may be a rotary slide valve, is actuated by a lever 29 which is flexibly connected to the framework 12 by a linkage 30.

A limit switch 31 is disposed between the lines 26, 27 to permit pneumatic pressure medium to flow between the lines 26, 27 when the stretcher bearing slide 14 is in its extreme forward position as shown in solid lines in the drawing. When the stretcher bearing slide 14 is moved backwards, pneumatic pressure medium cannot flow between the lines 26, 27 so that pneumatic pressure medium is not supplied to or from the pressure reservoir 24. This is done particularly when the stretcher bearing slide 14 is moved into an unloading or loading position indicated by reference numeral 14' to remove or receive a patient. The volume of gas in the suspension 20 and in the reservoir 24 is thereby maintained.

It is assumed that the stretcher 16 and therefore the bearing frame are loaded by the weight P of a patient in such a way that the limit switch 31 allows pneumatic pressure medium to flow between lines 26, 27 and the control valve 28 has adjusted the predetermined zero or datum position of the stretcher bearing frame 11 by supplying a corresponding quantity of the pneumatic medium to the pressure reservoir 24 and therefore to the-suspension 20. The stretcher bearing frame 11 can therefore swing about an optimum central position which corresponds to the load and which serves as a datum position.

As one patient is removed and a new patient is placed on the stretcher, the stretcher bearing slide 14 is moved backwards and the valve on the limit switch 31 prevents pneumatic pressure medium flowing between the lines 26, 27 so that the suspension 20 remains unchanged in position during both unloading and loading. When the slide 14 is moved back into its extreme forward position, pneumatic pressure medium can flow between the lines 26, 27 so that the control valve 28 resumes adjustment of the level of the stretcher bearing frame 11. the new patient is lighter than the previous one, the stretcher bearing frame with the patient will come to rest above the datum position. In this case the valve 28 discharges gas until the stretcher bearing frame has returned to the datum position.If the new patient is heavierthan the previous one, the stretcher bearing frame with the patient will occupy a position below the datum position. In this case the valve 28 will admit gas via the pressure reservoir 24, into the suspension 20 until the stretcher bearing frame comes to rest again in the datum position or can pivot about the datum position.

The throttle 23 acts as a vibration damper to stop pivoting of the stretcher bearing frame 11 after a preset time so that oscillations, which create discomfort for the patient, cannot be set up.

Any gas can be used as the pneumatic pressure medium, for example oxygen, which can be taken from a conventional storage cylinder.

Although the invention is important primarily for ambulances orforstretchers, the invention can also be used for other similar purposes, for example for bed frames orchairframes.

The invention is not limited to the illustrated exemplary embodiment. Thus, the stretcher bearing frame can be designed, for example without the stretcher bearing slide 14, the limit switch 31 being actuated, for example, directly by the movement of the stretcher. Also, the framework 12, for example, only needs to consist essentially of two longitudinal guide rails which are guided by a common scissortype system and guided to prevent transverse movement, and, in addition, the pneumatic spring suspension 20 can be designed and arranged in other ways to that illustrated. Moreover, the scissortype system 19 can be replaced by any other guide or support which prevents sideways movement.

Claims

1. A bearing frame including: pivotably mounted support means; adjustable pneumatic spring suspension means; and adjusting meansforautomati- cally regulating the pressure orvolume of gas in said suspension means in dependence upon the load on the support means so that the support means is substantially in a predetermined datum position irrespective ofthe load on the support means.

2. A frame as claimed in claim 1 in which the adjusting means includes a valve which is controlled in dependence upon the vertical position ofthe support means to control the flow of pressure medium to suspension means.

3. Aframe as claimed in claim 1 or2 in which the adjusting means includes a pressure reservoir for pressure medium upstream of the suspension means.

4. A frame as claimed in any preceding claim in which the support means is a longitudinally extending stretcher bearing frame pivotally mounted at one end about a transverse axis and at its other end is guided for movement in the vertical direction.

5. A frame as claimed in claim 4 in which the suspension means is located substantially in the central part of the stretcher bearing frame.

6. A frame as claimed in claim 4 or 5 in which said transverse axis is located at a loading end thereof.

7. A frame as claimed in any of claims 4 to 6 including scissor-type linkage means at said other end of the stretcher bearing frame for permitting said movement in the vertical direction.

8. A frame as claimed in any preceding claim in which the support means comprises a framework and an upper bearing slide which is guided in the longitudinal direction on the framework and serves to support a stretcher.

9. Aframe as claimed in any preceding claim in which the adjusting means includes a device for selectively preventing flow ofpressure medium to and from the suspension means.

10. A frame as claimed in claim 9 in which said claim is a limit switch operated by the position of the support means.

11. Aframe as claimed in any preceding claim in which the adjusting means includes vibration damping means.

12. A frame as claimed in claim 11 in which the damping means includes a damping throttle fitted in a line supplying pressure medium to the suspension means.

13. A bearing frame substantially as herein described with reference to and as shown in the accompanying drawing.

14. Stretcher bearing frame supported by an adjustable spring suspension, particularly for stretchers, characterised by a pneumatic spring sus pensionfor example, having pistons, diaphragms or the like the pneumatic volume of which or pneumatic pressure of which can be automatically regulated, depending on the loading of the resiliently swingable stretcher bearing frame, in such a way that - at least within a defined load range - a defined zero position in the height of the stretcher bearing frame is set in the event of a varying load, the volume or pressure being increased when the height falls below the said zero position, and the volume or pressure being reduced when the said zero position is exceeded.