Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-03-30
2001-03-13
Wu, Daniel J. (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S686100, C005S006000, C005S616000, C005S927000
Reexamination Certificate
active
06201481
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a safety device for furniture with at least one movable element which can be moved by a motor-driven positioning drive controlled by operating controls, particularly the head and/or foot of a base for a bed or recliner, or a seat and/or backrest element of an armchair, where the positioning of the element forms a gap in which an object or body part can become trapped as a result of the movement of the element.
BACKGROUND OF THE INVENTION
Furniture with at least one movable element is sufficiently known. The use of motor-driven positioning drives makes it possible to employ movable and adjustable elements in furniture. Adjusting an element of a piece of furniture is intended to enable the user to make comfortable and easy use of the furniture. Adjusting the element forms a gap in which an object or body part can become trapped as a result of the movement of the element. For example, a gap of this kind can form between the element and the piece of furniture. The movement of the element can also cause the formation of several gaps, for instance when the element is adjusted by a gearbox with rods. The gap can also be freely accessible or covered by fabric or other similar material.
One disadvantage of furniture of this kind is the danger of an object or body part becoming trapped in the gap as the result of movement of the element. This is very painful for the user and can lead to serious injury. If an object becomes trapped in the gap, this can cause damage to the object itself or to the furniture.
SUMMARY OF THE INVENTION
The invention is based on the object of providing a safety device which can be manufactured inexpensively with simple means and retrofitted without great effort and which effectively prevents the trapping of an object or body part.
According to the invention, the object is achieved by a safety device for furniture having at least one contact element in the gap which, when subjected to the pressure of an object or body part, closes an electric circuit which bridges a switch associated with an operating control, the closing of which prevents further movement of the positioning drive. In this context, the contact element is positioned in the gap in such a way that pressure is exerted on it when there is danger of something becoming trapped. The application of pressure causes the contact element to close the electric circuit. This electric circuit is connected in parallel to the switch of the operating control. Closing the electric circuit of the contact element makes it possible for the current to flow through the parallel electric circuit as if the switch of the operating control were activated, even if the switch of the operating control is open. If the switch of the operating control is closed or bridged, the further movement of the positioning drive is prevented. In this context, “further movement” means movement of the element which could cause something to become trapped even more. Closing the electric circuit bridges the switch of the operating control, the effect on the positioning drive being as if the operating control were activated, regardless of whether it has been activated by the user or not. The advantage of this is that no additional devices or switches are required in order to prevent the further movement of the positioning drive by closing an electric circuit. Consequently, the safety device according to the invention can also be simply retrofitted in conventional furniture with moving elements.
In a preferred example of the invention, the switch is a button on a hand-held control unit. In this context, a hand-held control unit is connected via wires to the furniture and its positioning drives, and is usually equipped with several different buttons. When using buttons, pressure applied to the button closes an associated electric circuit, thus setting the positioning drive in motion. A button of this kind usually works by connecting two electric contacts. Pressing the button activates a control element, such as a relay, which controls the drive in the positioning drive. When using a button of this kind, it is particularly easy to bridge the button, as the contact element need merely be connected in parallel to the button.
In a preferred example of the invention, a contact strip is provided as the contact element. The use of an elongated contact element in the form of a strip has the advantage that positioning the contact element at the edge of the gap can effectively prevent something from becoming trapped in the gap. For example, the contact strip can be mounted on a rod of the gearbox when using a change-gear train to position the element.
In an advantageous configuration, the contact element has a first contact and a second contact positioned at a distance from the first contact, where the first and second contacts can be brought into contact to form a current-carrying connection by applying pressure. The use of a contact element of this kind is inexpensive and simple to install in furniture. The use of contact elements of this kind is also advantageous in that they are of simple and durable design.
In a preferred configuration of the invention, a contact strip is provided as the first contact and a wire as the second contact, said wire being positioned parallel to, and at a distance from, a side surface of the contact strip and running in the longitudinal direction of the contact strip. Using a contact strip of this kind makes it particularly simple to establish a current-carrying point connection. For example, if the wire is positioned in the centre at a distance from a side surface of the contact strip, slight pressure can deflect the wire, thus creating a current-carrying connection and closing the electric circuit. For this purpose, the first contact in the form of a contact strip is expediently mounted on the furniture, so that the wire is pressed against the contact strip if there is a danger of something becoming trapped.
The contacts inside the contact strip are expediently sheathed in a plastic material, where the sheath is hollow in the area between the contacts to allow for the current-carrying connection of the contacts. Sheathing the contacts in a plastic material makes it possible to protect them against environmental influences and to protect the user from the electric voltage carried by the contacts. With plastic sheathing, the contact element can be cleaned easily, for example by wiping with a damp cloth. In order to be able to create a current-carrying connection between the contacts, the sheath has a chase in an area in which contact can occur. In the region of the second contact, the sheath encloses the contact in the form of an arc. The wall thickness of the sheath in this region is a factor which contributes to determining the pressure necessary to create a current-carrying connection.
The contact strip preferably covers the perimeter of the gap in which an object or body part can become trapped. Positioning the contact strip on the perimeter of the gap and not inside it reliably rules out the possibility of something becoming trapped.
The contact strip advantageously covers the upper perimeter of the gap in which an object or body part can become trapped. This position of the contact strip is advantageous because when something becomes trapped, an evasive motion is usually made in the upward direction, such as pulling the hand up and out of the gap in an armchair when the user is sitting in the armchair and reaches into the gap from above. By positioning the contact strip on the upper perimeter, the switch which prevents further movement of the element is bridged sooner as a result of the evasive motion. However, protection against trapping is also provided by other contact strip positions.
The positioning drive is expediently equipped with a DC motor and the bridging of the switch by the contact element activates a switching element which reverses the polarity of an electrical connection of the motor. Reversing the polarity of the electrical connections of a DC motor cau
Fildes & Outland, P.C.
OKIN Gesellschaft fur Antriebstechnik mbH & Co. KG
Pham Toan
Wu Daniel J.
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