Machine element or mechanism – Mechanical movements – Reciprocating or oscillating to or from alternating rotary
Reexamination Certificate
1999-12-17
2001-08-07
Bucci, David A. (Department: 3682)
Machine element or mechanism
Mechanical movements
Reciprocating or oscillating to or from alternating rotary
C005S616000, C297S362140
Reexamination Certificate
active
06269707
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a drive mechanism for adjusting parts in furniture for sitting and lying down, especially for adjustable armchairs, with a housing for accommodating two adjusting mechanisms driven by electromotors, the purpose of each of these being to turn a shaft equipped with a control lever, where the adjusting mechanisms each have an adjusting spindle which engages a gear unit at one head end, and an adjusting element which is bolted to the adjusting spindle, can be moved in the longitudinal direction and has a contact surface resting against the control lever, and are positioned in opposite directions, and where the adjusting mechanisms have a longitudinal side facing the shafts and a longitudinal side facing away from the shafts. In order to be in contact with the contact surface during the horizontal and vertical stroke motion of the adjusting element, the control lever can be positioned in a pocket-like recess in the contact surface. The control lever can also rest against the contact surface of the adjusting element under tension applied by an elastic element.
BACKGROUND OF THE INVENTION
A drive mechanism of this kind is known from DE 88 00 360 U, for example. This is a drive mechanism for slatted bed bases, in which shafts equipped with control levers are operated by two adjusting mechanisms driven by an electromotor. Parts of furniture for sitting or lying down are adjusted via brackets connected in articulated fashion to the shafts which can be turned in this way. Each of the adjusting mechanisms is driven by an electromotor, which drives an adjusting spindle via a gear unit. Turning the adjusting spindle moves the adjusting element and, by applying the adjusting element to the control lever, causes the shaft to turn. The adjusting mechanisms are mounted between the two shafts for this purpose. Furthermore, the adjusting mechanisms are mounted parallel to one another such that the head ends with the respective gear units for driving the adjusting spindles are adjacent to one another.
One disadvantage of these known configurations is that the shafts to be adjusted must be a certain minimum distance apart which approximately corresponds to the length of two adjusting mechanisms. In a configuration of a drive mechanism known from DE 88 00 360 U, the adjusting mechanisms are mounted next to one another between the shafts. A force transmitted from the adjusting mechanisms to the control levers of the shaft generates a reactive force acting on the drive mechanism. One disadvantage of such a configuration of the adjusting mechanisms is that the reactive forces are offset relative to one another and act on the shaft in different planes, thus generating a resulting torque on the drive mechanism.
SUMMARY OF THE INVENTION
The object of the present invention is to avoid the disadvantages described above and provide a drive mechanism which is particularly compact and suitable for use with closely spaced shafts, which are advantageous in armchairs, for example.
According to the invention, the object is solved in that the longitudinal side of the one adjusting mechanism facing away from the shafts is positioned opposite the longitudinal side of the other adjusting mechanism facing the shaft. In this context, both adjusting mechanisms lie in a common plane perpendicular to the rotational axes of the shafts. In this way, the control levers, via which the respective shafts can be turned, also lie in a common plane. Arranging the control levers in a common plane avoids the occurrence of a resulting torque on the drive mechanism.
Due to the fact that the longitudinal sides of the two adjusting mechanisms are positioned opposite one another, the minimum distance required between the shafts is reduced to approximately the minimum length of a single adjusting mechanism. Consequently, the drive mechanism is much more compact and suitable for use with closely spaced shafts.
In an advantageous configuration of the invention, the adjusting mechanisms are essentially positioned opposite one another without offset when the adjusting elements are in the position of the shortest vertical stroke. In the position of the shortest vertical stroke, the adjusting element is essentially screwed all the way up on the threaded spindle, and the entire adjusting mechanism is at its minimum length. This arrangement of the adjusting mechanisms allows a particularly small distance between the shafts.
The adjusting mechanisms are preferably arranged essentially parallel to one another in the housing. This makes a compact housing possible. The depth of the housing runs in the direction perpendicular to the connecting plane of the two rotational axes. The parallel arrangement of the adjusting mechanisms keeps the depth of the housing, in particular, to a minimum. In order to divert the reactive forces generated in the housing by the movement of the shafts, a web can provided between the two adjusting mechanisms which protects the housing against twisting forces and absorbs the reactive forces of both adjusting mechanisms.
The longitudinal direction of the adjusting mechanisms is preferably at an angle to the connecting plane of the shaft axes. The angled arrangement of the adjusting mechanisms can partially compensate for the varying distance of the adjusting mechanisms to the shaft, so that identical control levers can be used to operate the shafts. The use of identical control levers is particularly advantageous in that the lever arms, and thus also the forces exerted on the shaft by the adjusting elements, are essentially of equal size. The use of identical control levers also simplifies manufacturing, stocking and assembly of the drive mechanism. The varying distance of the adjusting elements to the shafts can be compensated for in particularly favourable fashion in that the head end of the adjusting element adjacent to the connecting plane is positioned closer to the connecting plane than its contact surface.
The housing advantageously consists of two integrally moulded half-shells with mounting elements for the gear units. The forces acting on the adjusting element via the control lever are transmitted via the threaded spindle to the gear unit and its mounting element. The mounting elements, which are integrally moulded in the half-shells of the housing, transmit the reactive forces to the housing. With a correspondingly sturdy connection of the housing areas in which the mounting elements are moulded, the reactive forces can be set against the tension forces in the housing. Another advantage of integrally moulded half-shells is that, during assembly of the drive, the adjusting mechanisms need only be inserted into one half-shell and are fixed in place in the housing by closing the second half-shell.
The adjusting elements are preferably guided in at least one half-shell by ribs arranged in the longitudinal direction. Guiding the adjusting elements in this manner increases their stability and enables precise guidance of the adjusting elements over the entire stroke range of the threaded spindle.
Each of the shafts is preferably mounted in a recess in the housing, where the recess has two side walls facing the shaft and the side wall farthest away from the gear unit of the adjusting element acting on the shaft forms a roughly right or acute angle with the normal direction of the contact surface at the contact point of the control lever. The normal direction of a surface at a point is the direction perpendicular to the surface through the point. Actuating the control lever exerts a force on the control lever at the contact point of the control lever in the normal direction of the contact surface. The force component in the direction of the connecting line from the contact point to the rotational axis of the shaft is transmitted via the control lever to the shaft as a transverse force. The force component perpendicular to the connecting line from the contact point to the rotational axis of the shaft is transmitted to the shaft as a torque.
The transverse force is partially ab
Bucci David A.
Fildes & Outland, P.C.
Joyce William C
OKIN Gesellschaft fur Antriebstechnik mbH & Co. KG
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