Synchronous chair mechanism and chair having same

Abstract

A synchronous chair mechanism is disclosed for simultaneously changing a seat and a backrest of a chair from a zero position in which the backrest is tilted to a minimum extent relative to the seat, into an end position in which the backrest is tilted to a maximum extent relative to the seat. The synchronous chair mechanism includes a base that is connectable to a substructure provided for setting up the chair. The synchronous chair mechanism also includes a backrest carrier on which the backrest is mountable, a seat support that is designed for holding a seat, and a spring element having a front end and a rear end.

Claims

1. A synchronous chair mechanism for simultaneously changing a seat and a backrest of a chair from a zero position in which the backrest is tilted to a minimum extent relative to the seat, into an end position in which the backrest is tilted to a maximum extent relative to the seat, comprising: a spring element; multiple basic elements; a latching structure; and a slide coupling piece, wherein the basic elements include a base that is connectable to a substructure provided for setting up the chair, the base having a base sliding surface and the slide coupling piece having a mating sliding surface, a backrest carrier on which the backrest is mountable, and a seat support that is designed for holding a seat, wherein the spring element has a front end and a rear end and is operatively connected to at least two of the basic elements, wherein the latching structure is provided on one of the basic elements, wherein the slide coupling piece is pivotably mounted on the front end of the spring element or on the rear end of the spring element, wherein outside the zero position of the synchronous chair mechanism, the slide coupling piece engages with the latching structure so that the slide coupling piece and the latching structure are fixedly connected to one another, wherein in the zero position of the synchronous chair mechanism, the slide coupling piece is decoupled from the latching structure so that the slide coupling piece is movable relative to the latching structure, as the result of which an action of the spring element may be changed, and wherein in the zero position of the synchronous chair mechanism, the mating sliding surface of the slide coupling piece rests against the base sliding surface of the base.

2. The synchronous chair mechanism according to claim 1, wherein the backrest carrier is mounted on the base so as to be pivotable about a first rotational axis, the seat support is connected to the front end of the spring element so as to articulate about a third rotational axis, the rear end of the spring element is hinged to the backrest carrier via a fourth rotational axis, and the first rotational axis, the third rotational axis, and the fourth rotational axis are different from one another.

3. The synchronous chair mechanism according to claim 1, wherein the latching structure is provided on the backrest carrier.

4. The synchronous chair mechanism according to claim 2, wherein the slide coupling piece is mounted on the rear end of the spring element so as to be pivotable about the fourth rotational axis.

5. The synchronous chair mechanism according to claim 2, wherein in the zero position of the synchronous chair mechanism, the slide coupling piece is decoupled from the latching structure of the backrest carrier so that the slide coupling piece is movable relative to the latching structure, as the result of which a distance between the fourth rotational axis and the first rotational axis may be changed in order to change the action of the spring element.

6. The synchronous chair mechanism according to claim 2, wherein the seat support is connected to the backrest carrier with articulation about a second rotational axis.

7. The synchronous chair mechanism according to claim 2, further comprising a connecting arm that is mounted on the seat support so as to be pivotable about the third rotational axis, wherein the spring element is connected to the connecting arm so as to be pivotable about a fifth rotational axis that is different from the first rotational axis, the third rotational axis, and the fourth rotational axis.

8. The synchronous chair mechanism according to claim 7, wherein the connecting arm is mounted on the base so as to be pivotable about a sixth rotational axis.

9. The synchronous chair mechanism according to claim 8, wherein a mating sliding surface against which the slide coupling piece rests when the synchronous chair mechanism is in the zero position is formed on one of the basic elements that is different from the basic element provided with the latching structure.

10. The synchronous chair mechanism according to claim 1, wherein the latching structure has a tooth row and the slide coupling piece has an engagement tooth, wherein outside the zero position of the synchronous chair mechanism, the engagement tooth of the slide coupling piece engages with the tooth row of the latching structure.

11. The synchronous chair mechanism according to claim 10, wherein outside the zero position of the synchronous chair mechanism, the mating sliding surface of the slide coupling piece is spaced apart from the base sliding surface of the base, and in the zero position of the synchronous chair mechanism the engagement tooth of the slide coupling piece is spaced apart from the tooth row of the latching structure.

12. The synchronous chair mechanism according to claim 2, further comprising a control device via which the slide coupling piece is movable along the latching structure in the zero position of the synchronous chair mechanism, so that a distance between the first rotational axis and the fourth rotational axis may be changed.

13. The synchronous chair mechanism according to claim 12, wherein the control device includes a rotary lever that is rotatably connected to the backrest carrier, a gearwheel situated on the rotary lever, and a gearwheel receptacle with toothing that is fixedly connected to the fourth rotational axis, the gearwheel engaging with the toothing of the gearwheel receptacle so that rotation of the rotary lever results in displacement of the fourth rotational axis relative to the backrest carrier.

14. The synchronous chair mechanism according to claim 6, wherein the first rotational axis is situated between the second rotational axis and the fourth rotational axis.

15. The synchronous chair mechanism according to claim 2, further comprising a further backrest carrier and a further slide coupling piece, wherein the backrest carrier together with the slide coupling piece, and the further backrest carrier together with the further slide coupling piece, have a mirror-symmetrical design and are laterally situated on the seat support in a mirror-symmetrical manner.

16. A chair having a seat, a backrest, a substructure, and a synchronous chair mechanism according to claim 1, wherein the seat is held by a seat support of the synchronous chair mechanism, the backrest is mounted on a backrest carrier of the synchronous chair mechanism, and the substructure is connected to a base of the synchronous chair mechanism.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous embodiments of the invention result from the following description of exemplary embodiments of the invention, with the aid of the schematic drawings. In particular, the synchronous chair mechanism according to the invention and the chair according to the invention are explained in greater detail based on exemplary embodiments, with reference to the appended drawings, which show the following:

(2) FIG. 1 shows a schematic diagram of a first exemplary embodiment of a synchronous chair mechanism according to the invention, in a position in which a relatively small supporting force for a backrest is adjusted;

(3) FIG. 2 shows a schematic diagram of the synchronous chair mechanism from FIG. 1, in which a spring element is decoupled from a backrest carrier;

(4) FIG. 3 shows a schematic diagram of the synchronous chair mechanism from FIG. 1, in a position in which a relatively large supporting force for a backrest is adjusted;

(5) FIG. 4 shows a perspective detailed view of the backrest carrier, a base, and a slide coupling piece of the synchronous chair mechanism from FIG. 1 in its zero position;

(6) FIG. 5 shows a perspective detailed view of the components from FIG. 4 during a change from the zero position of the synchronous chair mechanism;

(7) FIG. 6 shows a perspective detailed view of the components from FIG. 4 while outside the zero position of the synchronous chair mechanism;

(8) FIG. 7 shows a perspective, partially sectional view of a second exemplary embodiment of a synchronous chair mechanism according to the invention;

(9) FIG. 8 shows a schematic diagram of certain components of the synchronous chair mechanism from FIG. 7 in their zero position;

(10) FIG. 9 shows a schematic diagram of the components from FIG. 8 during a change from the zero position of the synchronous chair mechanism; and

(11) FIG. 10 shows a schematic diagram of the components from FIG. 8 outside the zero position of the synchronous chair mechanism.

(12) Certain expressions are used in the following description for practical reasons, and are not to be construed as limiting. The words “right,” “left,” “bottom,” and “top” denote directions in the drawings to which reference is made. The expressions “inwardly,” “outwardly,” “below,” “above,” “left,” “right,” or the like are used to describe the arrangement of denoted parts relative to one another, the movement of denoted parts relative to one another, and the directions toward or away from the geometric midpoint in the invention as well as designated parts thereof, as illustrated in the figures. These spatial relative indications also encompass other positions and orientations than illustrated in the figures. For example, when a part illustrated in the figures is turned upside down, elements or features that are described as “below” are then “above.” The terminology includes the words expressly mentioned above, derivations of same, and words of similar meaning.

(13) To avoid repetitions in the figures and the associated description of the various aspects and exemplary embodiments, certain features are to be understood collectively for various aspects and exemplary embodiments. The omission of an aspect in the description or in a figure does not imply that this aspect is absent in the associated exemplary embodiment. Rather, such an omission may serve to improve clarity and prevent repetitions. In this regard, the following applies for the entire further description: If reference numerals are contained in a figure for the purpose of graphical clarity, but are not mentioned in the directly corresponding text in the description, reference should be made to their explanation in the preceding description of the figures. Furthermore, if reference numerals are mentioned in the text in the description that directly corresponds to a figure, but are not contained in the associated figure, reference should be made to the preceding and subsequent figures. Similar reference numerals in two or more figures stand for similar or identical elements.

(14) FIG. 1 shows a schematic diagram of a first exemplary embodiment of a synchronous chair mechanism 1 according to the invention, having the following basic elements: a base 2, a backrest carrier 3, and a seat support 4. The synchronous chair mechanism 1 is installed in a first exemplary embodiment of a chair according to the invention, with a substructure for setting the chair on the floor, a backrest, and a seat. The base 2 is connected to the substructure of the chair. The backrest of the chair is mounted on the backrest carrier 3. The seat of the chair is fastened to the seat support 4.

(15) The synchronous chair mechanism 1 also has a connecting arm 5, a slide coupling piece 6, and a spring element 8 with a coil spring assembly 81, a front end 82, and a rear end 83. The coil spring assembly 81 contains multiple coil springs that extend between the front end 82 and the rear end 83.

(16) The components of the synchronous chair mechanism 1 are connected to one another via multiple rotational axes 7 that allow ergonomic simultaneous movement of the seat and the backrest relative to one another. The backrest carrier 3 is mounted on the base 2 so as to be pivotable about a first rotational axis 71, and is mounted on the seat support 4, near its rear side 41, via a second rotational axis 72. Near its front side 42, the seat support 4 is connected to an upper longitudinal end of the connecting arm 5 so as to be pivotable about a third rotational axis 73. A lower longitudinal end of the connecting arm 5 is in turn mounted on the base 2 so as to be pivotable about a sixth rotational axis 76. The base 2, the backrest carrier 3, the seat support 4, and the connecting arm 5 thus form a quadrangle in which the four angles are flexibly adjustable via the first, the second, the third, and the sixth rotational axes 71, 72, 73, 76.

(17) The spring element 8 at its front end 82 is fastened via a fifth rotational axis 75 to the connecting arm 5, in the lower half of the connecting arm 5 between its lower and upper longitudinal ends. At its rear end 83, the spring element 8 is pivotably connected to the slide coupling piece 6 via a fourth rotational axis 74. For this purpose, the slide coupling piece 6 is provided with a borehole 61 through which an axial rod 741 (not visible in FIG. 1) extends.

(18) The slide coupling piece 6 is also provided with engagement teeth 62 that engage with a tooth row 31 of the backrest carrier 3. The tooth row 31 is designed as a latching structure situated vertically on the backrest carrier 3 in an area below the first rotational axis 71. The spring element 8 is thus clamped between the connecting arm 5 and the backrest carrier 3. The base 2 has a ramp unit 22 having a sliding surface 21 that extends in the direction of the slide coupling piece.

(19) In the situation illustrated in FIG. 1, the backrest of the chair is acted on by pressure. The backrest carrier 3 is thereby tilted about the first rotational axis 71, so that the second rotational axis 72 is moved to the right and the fourth rotational axis 74 is moved to the left. The synchronous chair mechanism 1 is thus outside its zero position. The engagement teeth 62 of the slide coupling piece 6 that engage with the tooth row 31 thus fixedly connect the slide coupling piece, and thus also the rear end 83 of the spring element 8, to the backrest carrier 3. The spring element 8 is thereby compressed, and presses against the backrest carrier 3 below the first rotational axis 71. A torque 78 that acts in the counterclockwise direction at the first rotational axis 71 is thus generated on the backrest carrier 3. The distance between the first rotational axis 71 and the fourth rotational axis 74 forms an active lever 77 that concurrently determines the magnitude of the torque 78.

(20) The slide coupling piece 6 is situated near an upper end of the tooth row 31 in FIG. 1. The distance between the first rotational axis 71 and the fourth rotational axis 74 is accordingly relatively small, so that the active lever 77 is relatively short. The torque 78 is similarly relatively low. The torque 78 in turn specifies the supporting force of the backrest of the chair, which in the situation shown in FIG. 1 is relatively small. The backrest thus has a rather soft adjustment in FIG. 1.

(21) The synchronous chair mechanism 1 is shown in its zero position in FIG. 2. The backrest of the chair is not acted on by pressure, and the backrest carrier 3 is moved counterclockwise about the first rotational axis 71, all the way to the left, by the spring element 8. The second rotational axis 72 is hereby moved to the left and the fourth rotational axis 74 is moved to the right. The second rotational axis 72 is situated quasi-vertically above the first rotational axis 71, approximately at the level of the third rotational axis 73. The seat support 4 together with the seat is thus horizontally oriented in the zero position.

(22) Due to rotating the backrest carrier 3 counterclockwise about the first rotational axis, the area of the backrest carrier 3 below the first rotational axis 71 together with the tooth row 31 is moved to the right. The tooth row 31 is hereby situated farther to the right than the sliding surface 21 of the base 2. The slide coupling piece 6 with a mating sliding surface 63 thus rests against the sliding surface 21 of the base 2. The slide coupling piece 6 together with the spring element 8 is thus decoupled from the backrest carrier 3.

(23) As indicated by the double arrow in FIG. 2, in the zero position of the synchronous chair mechanism 1 the slide coupling piece 6 may be moved along the tooth row 31 by sliding it with its mating sliding surface 63 along the sliding surface 21 of the base. The distance between the fourth rotational axis 74 and the first rotational axis 71 may thus be changed as needed.

(24) FIG. 3 once again illustrates the synchronous chair mechanism 1 outside the zero position. The engagement teeth 62 of the slide coupling piece 6 engage near a lower end of the tooth row 31 of the backrest carrier 3. The distance between the first rotational axis 71 and the fourth rotational axis 74 is relatively large. Accordingly, the active lever 77 is relatively long, and the torque 78 generated on the first rotational axis 71 by the spring element 8 is relatively high. The supporting force of the backrest of the seat is thus fairly large in the situation shown in FIG. 2.

(25) FIGS. 4, 5, and 6 show the interaction of the base 2, the backrest carrier 3, and the slide coupling piece 6 when the synchronous chair mechanism 1 is changing from its zero position. In particular, of the base 1 and the backrest carrier 3, only the areas around the slide coupling piece 6 are illustrated for the sake of clarity.

(26) The synchronous chair mechanism 1 is in the zero position in FIG. 4. It is apparent that the ramp unit 22 has two parallel sliding surfaces 21 and a gap 23 in between. The slide coupling piece 6, similarly as for the two sliding surfaces 21, is provided with two corresponding mating sliding surfaces 63 that extend in parallel next to the engagement teeth 62. The backrest carrier 3 is moved back and forth in the gap 23, about the first rotational axis 71, until the engagement teeth 62 are completely decoupled from the tooth row 31. In the zero position in FIG. 4, the slide coupling piece 6 may be moved along the sliding surfaces 21 and along the tooth row 31.

(27) FIG. 5 shows the synchronous chair mechanism 1 during the coupling of the backrest carrier 3 to the slide coupling piece 6. The backrest carrier 3 is hereby tilted clockwise about the first rotational axis 71, so that the tooth row 31 is moved in the direction of the slide coupling piece 6. The engagement teeth 62 of the slide coupling piece 6 increasingly engage with the tooth row 31, and the mating sliding surfaces 63 are increasingly lifted off from the sliding surfaces 21. The slide coupling piece is thus easily tilted about the fourth rotational axis 74, so that the slide coupling piece 6 increasingly securely interlocks with the tooth row 31.

(28) In FIG. 6, the backrest carrier 3 is tilted about the first rotational axis 71 until the slide coupling piece is completely lifted off or removed from the ramp unit 22. At the same time, the engagement teeth 62 engage firmly with the tooth row 31, so that the slide coupling piece 6 is securely and fixedly connected to the backrest carrier 30. Outside the zero position of the synchronous chair mechanism 1, displacing the slide coupling piece 6 along the backrest carrier 30, and correspondingly changing the distance between the first rotational axis 71 and the fourth rotational axis 74, is no longer possible in the situation from FIG. 6.

(29) FIG. 7 shows a second exemplary embodiment of a synchronous chair mechanism 10 according to the invention, having the following basic elements: a base 20, a backrest carrier 30, a further backrest carrier, and a seat support 40. The synchronous chair mechanism 10 is installable in a second exemplary embodiment of a chair according to the invention, with a substructure for setting the chair on the floor, a backrest, and a seat. For this purpose the base 20 is connected to the substructure, the backrest is mounted on the backrest carrier 30, and the seat is fastened to the seat support 40.

(30) The seat support 40 includes an essentially flat top side 440 that is equipped with four mounting feet 430 for fastening the seat, a front side 420, and a rear side 410. The base 20 is shown in a partially sectional view in FIG. 7 so that the components inside the synchronous chair mechanism 10 are visible.

(31) The synchronous chair mechanism 10 has a connecting arm 50, a slide coupling piece 60, a further slide coupling piece, a spring element 80 with two coil springs 810, a front end, and a rear end. The coil springs 810 extend between the front end and the rear end of the spring element 80. The further slide coupling piece, the further backrest carrier, and the associated components of the base 20 have a mirror-symmetrical design with respect to the slide coupling piece 60, the backrest carrier 30, and the associated components of the base 20, and are laterally situated on the seat support 40 in a mirror-symmetrical manner.

(32) The backrest carrier 30 is mounted on the base 20 so as to be pivotable about a first rotational axis (concealed in the figure), and is mounted on the seat support 40, near its rear side 410, via a second rotational axis 720. Near its front side 420, the seat support 40 is connected to two upper longitudinal ends of the connecting arm 50 so as to be pivotable about a third rotational axis 730. Two lower longitudinal ends of the connecting arm 50 are mounted on the base 20 so as to be pivotable about a sixth rotational axis 760. The base 20, the backrest carrier 30, the seat support 40, and the connecting arm 50 thus form a quadrangle in which the four angles may be changed via the first, the second, the third, and the sixth rotational axes 710, 720, 730, 760.

(33) The spring element 80 at its front end is connected via a fifth rotational axis 750 to the connecting arm 50 between its lower and upper longitudinal ends. The spring element 80 at its rear end is pivotably connected to the slide coupling piece 60 via a fourth rotational axis 740. An axial rod 7410 that extends into a borehole 610 of the slide coupling piece 60 is provided for this purpose.

(34) The slide coupling piece 60 is provided with engagement teeth 620 (not visible in FIG. 7) that may engage with a tooth row 310 of the backrest carrier 30. The tooth row 310 is designed as a latching structure from top to bottom on the backrest carrier 30, in an area below the first rotational axis 710. The spring element 80 is thus clamped between the connecting arm 50 and the backrest carrier 30. The base 20 has a rib 220 that forms a sliding surface 210 that extends in the direction of the slide coupling piece 60.

(35) In the situation illustrated in FIG. 7, no pressure is exerted on the backrest of the chair, and the backrest or the backrest carrier 30 is not deflected or tilted backward. The synchronous chair mechanism 10 is thus in the zero position, in which the slide coupling piece 60 is displaceable along the sliding surface 210 of the base 20 and along the tooth row 310 of the backrest carrier 30.

(36) The synchronous chair mechanism 10 has a control device 90 for displacing the slide coupling piece 60. The control device 90 includes a rotary lever 910 that is rotatably supported on the backrest carrier 30, and which toward the outside is designed as a handle.

(37) A gearwheel 920 at its inner longitudinal end is nonrotatably situated on the rotary lever 910. The control device 90 also includes a gearwheel receptacle 930 with toothing that is fixedly connected to the fourth rotational axis 740, i.e., to the slide coupling piece 60 and the spring element 80. The gearwheel 920 is situated in the gearwheel receptacle 930, and engages with the toothing of the gearwheel receptacle 930. Rotating the rotary lever 910 causes the gearwheel 920 to rotate in the gearwheel receptacle 930. As a result, the gearwheel 920 moves up and down in the gearwheel receptacle, depending on the rotational direction. The slide coupling piece 60 in the zero position may thus likewise be moved up and down, so that a distance between the first rotational axis 710 and the fourth rotational axis 740 may be changed. In the situation shown in FIG. 7, the rotary lever 910 is rotated counterclockwise to the maximum extent, so that the slide coupling piece 60 is moved upwardly to the maximum extent.

(38) FIGS. 8, 9, and 10 show the interaction of the base 20, the backrest carrier 30, and the slide coupling piece 60 while changing the synchronous chair mechanism 10 from its zero position. Of the base 10 and the backrest carrier 30, only the areas around the slide coupling piece 60 are illustrated for the sake of clarity.

(39) The synchronous chair mechanism 10 is in the zero position in FIG. 8. The slide coupling piece 60 is illustrated in cross section, it being apparent that the slide coupling piece has a quasi-sleeve-shaped design. On its right side the slide coupling piece 60 has a mating sliding surface 630, which in the zero position rests against the sliding surface 210 of the rib 220 of the base 20. Engagement teeth 620 are formed on the right side of the slide coupling piece 60, adjacent to the mating sliding surface 630. In the zero position, the engagement teeth are adjacent to and spaced apart from the tooth row 310 of the backrest carrier 30. In turn, a convexly rounded first contact surface 640 is formed on the right side of the slide coupling piece 60, adjacent to the engagement teeth 620. The first contact surface 640 of the slide coupling piece 60 rests against a congruent, concavely rounded second contact surface 320 of the backrest carrier 30. The second contact surface 320 extends next to and along the tooth row 310.

(40) The borehole 610 is recessed into the slide coupling piece 60 in the manner of a blind hole. The borehole toward its open side has an outer extension 6110 facing away from the mating sliding surface 630, and toward its closed side has an inner extension 6120 situated opposite from the first contact surface 640. An axial rod 7410 of the fourth rotational axis 740 extends into the borehole 610. The inner extension 6120 and the outer extension 6110 define play of the slide coupling piece 60 on the axial rod 7410, which allows the slide coupling piece 60 to be tilted to a certain extent about a tilt axis that intersects the fourth rotational axis 740 at a right angle. The axial rod 7410 is also connected to the spring element 80.

(41) FIG. 9 shows the synchronous chair mechanism 1 during the coupling of the backrest carrier 30 to the slide coupling piece 60. The backrest carrier 30 is hereby tilted so that it moves from right to left. Via the mutually contacting first contact surface 640 and second contact surface 320, the backrest carrier 30 presses the slide coupling piece 60 away from the rib 220 of the base 20. The rounded shape of the contact surfaces 640, 320, and the outer extension 6110 and the second extension 6120, allow the slide coupling piece 60 to be rotated about the tilt axis so that the engagement teeth 620 increasingly engage with the tooth row 310.

(42) In FIG. 10, the backrest carrier 30 is tilted about the first rotational axis 71 and moved to the left until the slide coupling piece 60 is completely removed from the rib 220. At the same time, the slide coupling piece 60 is tilted until the engagement teeth 620 firmly engage with the tooth row 310 and the slide coupling piece 60 is fixedly connected to the backrest carrier 30. Outside the zero position of the synchronous chair mechanism 10, displacing the slide coupling piece 60 along the backrest carrier 30, and correspondingly changing the distance between the first rotational axis 710 and the fourth rotational axis 740, is not possible in the situation from FIG. 7.

(43) Although the invention is illustrated and described in detail by means of the figures and the associated description, respectively, this illustration and this detailed description are to be understood as illustrative and by way of example, and not as limiting to the invention. In certain cases, well-known structures and techniques may not be shown or described in detail so as not to overelaborate the invention. It is understood that experts in the field may make revisions and modifications without departing from the scope of the following claims. In particular, the present invention encompasses further exemplary embodiments with any combinations of features, which may differ from the feature combinations explicitly described.

(44) The present disclosure also includes embodiments with any combination of features that are stated or shown in the preceding or subsequent discussion of various embodiments. The present disclosure likewise includes individual features in the figures, even if they are shown there in conjunction with other features, and/or are not mentioned in the preceding or subsequent discussion. In addition, the alternatives of embodiments and individual alternatives of their features that are described in the figures and in the description may be excluded from the subject matter of the invention or the disclosed subject matter. The disclosure includes embodiments that comprise only the features described in the claims or in the exemplary embodiments, as well as embodiments that comprise additional other features.

(45) In addition, the expression “include” and derivations thereof does not exclude other elements or steps. Likewise, the indefinite article “a” or “an” does not exclude a plurality. The functions of multiple features stated in the claims may be met by one unit or one step.

(46) The terms “essentially,” “approximately,” “about,” and the like in conjunction with a property or a value in particular also define the exact property or the exact value. The terms “approximately” and “about” in conjunction with a given numerical value or range may refer to a value or range that is within 20%, within 10%, within 5%, or within 2% of the given value or range. None of the reference numerals in the claims is to be construed as limiting the scope of the claims.