1. Field of the Invention
The invention relates to a bed which is in particular a sickbed or a nursing bed.
2. Description of Related Art
Sickbeds or nursing beds are normally height-adjustable for making it easier for nursing staff to nurse a patient or a test person. Such beds normally comprise side parts on both sides of a lying surface, said side parts being adapted to prevent the test person from falling out of the bed.
It is known that, depending on their mental or physical condition, the test persons try to climb over the side parts in order to leave the bed. In doing so, the test persons may fall when climbing over the side parts, which entails a considerable risk of injury.
Thus it is desirable that a sickbed or nursing bed can be lowered to such an extent that the upper edges of the side parts are located at a height where there is only a small risk of injury for a test person climbing over the side bars. Ideally, the bed can be lowered to such an extent that its lying surface is located only a few centimeters (20 to 30 cm, for example) above a floor. At such a low position, a side protection can even be omitted since there is hardly any risk of injury if a test persons “falls” out of the bed from a height of only a few centimeters.
It is common practice to realize height-adjustable bedsteads of sickbeds or nursing beds either by telescoping or length-adjustable vertical legs or by so-called scissor-type mechanisms. The scissor-type mechanisms offer the advantage that the beds can be lowered to an extremely low level. Examples of scissor-type mechanisms for height-adjustable bedsteads are shown in DE 43 20 092 A1, DE 44 06 784 C1 and DE 199 15 431 A1. The known height-adjustable beds having a scissor-type mechanism or scissor levers comprise a frame having frame side and frame transverse parts, wherein pivotable legs are arranged at the head end and the foot end of the frame. The legs comprise lower ends supported on the floor, while their opposite ends are slidably guided along the frame. The legs are adapted to be pivoted via a centrally arranged drive mechanism such that the bedstead is lifted or lowered.
For further increasing the comfort, sickbeds or nursing beds comprise adjustable lying surfaces, i.e. adjustable mattress supporting devices. These devices comprise individually adjustable or pivotable portions which are adapted to be adjusted by a motor. An adjustment drive is located below the lying surface or the mattress supporting surface of the mattress supporting device. The height-adjustable bedstead of the sickbed or nursing bed may not collide with this adjustment drive, which means that the bed can be lowered only to a position in which the lying surface is located at such a height above the floor that a side protection cannot be omitted. In other words, the adjustment drive thus prevents sickbeds or nursing beds equipped with a scissor-type mechanism or a similar height adjustment means from being lowered down to a location as near to the floor as possible.
Sickbeds or nursing beds further comprise a fixing brake for locking the bed in position with the purpose of preventing any unintentional movement of the beds which are normally provided with guide rollers and castors. Normally, such fixing brakes are adapted to be operated by hand or by foot. This involves the risk that the nursing staff unintentionally do not operate the fixing brake of the sickbed or the nursing bed when the bed is being lowered or is completely lowered. Thus the bed can inadvertently move which entails a risk of injury of the patients or test persons on the one hand, and the risk of damage to functional units of the bed on the other hand since there is only little space between the functional units and the floor in the completely lowered condition.