JPH0720756B2 - Head lifting device for universal parallel ruler - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a head lifting device for a rail-type universal parallel ruler, which is characterized in that the head lifting limit position can be set to be adjustable.

[Prior art]

This type of rail-type parallel ruler is described in Japanese Patent Application Laid-Open No. 59-199298 and many other publications, in which a head to which a straight ruler is attached is in a state of being substantially parallel to a vertical cursor on a vertical cursor. It is connected so that it can move up and down as it is, and the head is in close contact with the drawing plate surface, and even if the head is released from the hand, the head maintains the close contact state by its own weight, and the head is raised in the state of being raised. When the hand is released from the head, the head is configured to be held in a state of being levitated from the surface of the drawing board by the spring force. The head is levitated above the drawing board surface when the head is moved largely on the drawing board, to prevent the straight ruler from rubbing on the drawing board to prevent the drawings from getting dirty, or the head drawing board surface. This is because the movement in the horizontal direction can be performed lightly. The ascending direction parallel movement limit setting stopper of the head is set at a fixed position.

[Problems to be Solved by the Invention]

The drawing board supporting the universal parallel ruler is usually supported on the drafting table so that it can be set at an arbitrary inclination angle within a range of horizontal and vertical directions. The drawing person sets the drawing board at a desired inclination angle and uses it. The straightedge connected to the head is made of a long plastic and has elasticity in itself. Therefore, when the straight edge is brought into close contact with the surface of the drawing board and the head is lifted to levitate against the surface of the drawing board, the straightness of the straight edge 50 becomes gravitational due to its elasticity and its own gravity, as shown in FIG. Then, the tip hangs down in the direction of the surface of the drawing board. This hanging condition depends on the inclination angle of the drawing board 24, and is the largest when the drawing board 24 is horizontal, and when the drawing board 24 is vertical,
Straightedge 50 does nothing. The operability is better when the head 18 is located at the upper limit position as close to the drawing board surface as possible. If the head limit position is far away from the drawing board surface when drawing with a straight edge,
The head has to be lowered significantly. However, for example, in the state where the inclination angle of the drawing board is 45 degrees, even if the proper head raising limit position is set, even if the head is raised when the drawing board is set horizontally, the straight edge is shown in FIG. , As shown by the dotted line, it will come into contact with the surface of the drawing board 24. For this reason, the ascending limit position of the head 18 has to be set at a high position above the drawing board surface so as to correspond to all the drawing board inclination angles, and the operability of the head is poor. It is an object of the present invention to solve the above-mentioned problems by making it possible to adjust the ascending limit position of the head.

[Means for solving problems]

In order to achieve the above object, the present invention provides a horizontal rail 40 that can be fixed to the drawing board 24, a vertical rail 44 that is movably connected to the horizontal rail 40 at a right angle relationship, and the vertical rail 44. A vertical cursor 2 movably attached, a head 18 to which a straight ruler is connected, an elevating and lowering guide mechanism for connecting the head 18 to the vertical cursor 2 so as to move the head 18 in a substantially vertical direction, and the head 18. In a device provided with a head elastic mechanism for urging in the ascending direction to prevent the head 18 from falling at an arbitrary ascending position, one of the plurality of links constituting the elevating guide mechanism 20a, 86 In the link 20a, 86
Other links 4,84 that are displaced in the rotational direction with respect to the one link 20a, 86 as the head 18 pivotally supported by
It is arranged so as to face a, and the facing interval is arranged so as to be narrowed by the rotational displacement of the other link 4, 84a with respect to the one link 20a, 86 as the head 18 rises. When the head 18 rises to a predetermined height, the heads 18 collide with the other links 4, 84a and set stoppers 64, 112 for setting the rising limit position of the head 18, and the head 18
And a stopper position adjusting mechanism for changing the interval at which the stoppers 64 and 112 face the other links 4 and 84a when the head is stationary and changing the rising limit position of the head 18.

[Action]

In the above structure, the stopper position adjusting mechanism is operated every time the inclination angle of the drawing board is changed to set an appropriate head rising locking position. In this state, when the operator raises the head 18 by hand, the rise of the head 18 is prevented when the straight edges 50 and 52 are slightly separated from the sheet surface on the drawing board 24. In this state, if the operator presses the head 18 in a direction horizontal to the surface of the drawing board 24, the head 18 is parallel to the drawing board 24 with the straight edges 50 and 52 not contacting the paper surface. It can be moved in a desired direction in a plane.

【Example】

Hereinafter, the configuration of the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings. In FIG. 5, reference numeral 24 denotes a drawing board, which is supported by a support frame of a drafting table that can be tilted so as to be fixed at a desired tilt angle between horizontal and vertical with respect to the floor surface. Reference numeral 40 denotes a horizontal rail arranged on the upper side of the drawing board 24, to which a horizontal cursor 42 is movably attached. An upper end of a vertical rail 44 is connected to the horizontal cursor 42. The lower end of the vertical rail 44 is movably mounted on the drawing board 24 via the tail roller. Reference numeral 2 denotes a vertical cursor movably attached to the vertical rail 44, to which a supporting substrate 20 of the head 18 is connected via a well-known lifting guide mechanism 46. Direct rulers 50 and 52 are detachably attached to the ruler mounting plate 48 of the head 18. As shown in FIGS. 2 and 3, the elevating guide mechanism 46 includes a fixed link 2a including a rising piece 2a fixed to the vertical cursor 2.
And a swing link 4, a pair of swing links 6 and 6, and a quadrangle link composed of lifting links 12 and 20a. Each of these links 2a, 4, 6, 6, 12, 20a is pivoted with respect to each other by axes 8, 14, 10, 16 so as to form a quadrangle when viewed from the side. The plate-shaped link 4 is composed of a flat plate portion 4b and side plate portions 4c, 4c vertically formed on both sides of the flat plate portion 4b. As shown in FIG. 3, one side of the side plate portions 4c, 4c of the link 4 is provided with pivot bearings 54, 56 at both ends of the pivot shaft 8 fixed to the fixed link 2a fixed to the vertical cursor 2. The drawing board 2
It is rotatably supported in a plane perpendicular to the four planes. One end of the link 6 is attached to the fixed link 2a by the shaft 10.
It is rotatably supported in a plane perpendicular to the plane of the drawing plate. The link 20a is formed integrally with the support substrate 20 of the head 18. The bearing portion of the pair of protrusions 20b, 20b formed on the link 20a is
Pivot bearings 58, 60 are provided on the other side plates 4c, 4c of the link 4.
It is rotatably fitted to a pivot shaft 14 which is rotatably supported via. The bearing portion above the link 12 is rotatably fitted to the pivot shaft 14, and the lower portion of the link 12 and the other end portion of the link 6 are rotatable by a shaft 16 as shown in FIG. Connected to. The link 20a is interlocked with the link 12 to move up and down by rocking of the links 4, 6 and 6, and the two links 20a and 12 constitute an elevating link which is one side of a quadrangle. The side surface of the link 20a fixed to the support substrate 20 is in contact with the stopper shaft 22 that is screwed into the screw hole of the link 12. Reference numeral 64 denotes a head rising direction regulating stopper that is screwed into a screw hole 21 formed in the projecting portion 20b of the link 20a, and a side surface of the projecting piece 4a that is projectingly provided on the lower surface of the flat plate portion 4b of the link 4 at substantially the center. Is facing. Reference numeral 66 denotes a pair of parallel guide pins (the other one is not shown) which are provided below the fixed link 2a fixed to the vertical cursor 2 in a direction horizontal to the plane of the drawing board. A pair of shaft holes of the slide book 30 are slidably fitted. The slide block
As shown in FIG. 1, a screw hole is formed in the screw 30, and a spring adjusting screw 34 with a knob is screwed into the screw hole, and a conical tip end of the screw 34 has a screw hole as shown in FIG. Is fitted in the conical concave shape formed in the fixed link 2a. 26,26
Is a pair of links formed in a substantially dogleg shape, and a spring hooking shaft 68 is installed at one end of each of these links,
A shaft hole formed in a substantially middle portion of 6 is rotatably fitted to the pivot shaft 8. As shown in FIG. 1, the other ends of the links 26, 26 are rotatably connected to a projecting piece 4a provided on the link 4 by a shaft 28. A hook portion of a spring 32 composed of three coil springs A, B, and C is engaged between the spring hook shaft 68 and a spring hook shaft 72 provided on the slide block 30. Next, the operation of this embodiment will be described. Hold the handle of the head 18 with your hand and
When the head 18 is pulled up in the rising direction with the side surface of the rising portion 20a of the
4, 6 and 26 oscillate counterclockwise in FIG. 2 about the pivot shafts 8 and 10, and the link 12 rises while maintaining a substantially predetermined angle with respect to the surface of the drawing board 24. 18 rises in a state of being kept substantially parallel to the surface of the drawing plate 24. The moving range of the head 18 in the ascending direction in the parallel state is determined by the protrusion amount of the stopper 64, and when the stopper 64 collides with the side surface of the projecting piece 4a of the link 4, further elevation of the head 18 is blocked. When the hand is released from the handle of the head 18 at an arbitrary raised position within the range in which the head 18 can be raised, the weight of the head 18 causes the link 4 to move about the pivot shaft 8 as a center.
In the figure, rotational torque is generated in the clockwise direction. The magnitude of the rotational torque acting on the link 4 by the rotational torque and the tensile elastic force of the spring 32 is adjusted in advance so as to be substantially the same. This adjustment can be performed by rotating the spring adjusting screw 34 according to the inclination angle of the drawing board 24 and moving the slide block 30 in the left-right direction in FIG. In this embodiment, when the head 18 is brought into close contact with the surface of the drawing board 24, the coil spring 32 approaches the shaft 8 and the torque of the link 26 in the counterclockwise direction in FIG. head
Although the head is configured to maintain a close contact state by its own weight even if the hand is released from the head 18, if the hand is released from the head 18 in a state where the head 18 is in close contact with the drawing plate surface, the head 18 is spring-loaded. It may be configured such that it slightly floats up from the surface of the drawing board 24. As is clear from the above description, the link 26 and the spring 32 constitute a head elastic mechanism for urging the head 18 in the ascending direction to prevent the head 18 from falling at an arbitrary ascended position. . Further, the screw hole 21 formed in the link 20a and the screw formed in the stopper 64 for screwing into the screw hole 21 constitute a stopper position adjusting mechanism for changing the head rising locking position of the stopper 64. There is. Next, another embodiment will be described with reference to the embodiments shown in FIGS. Reference numeral 80 denotes a rising portion of a vertical cursor movably attached to the vertical rail, and the rising portion constitutes a fixed link of a known lifting guide mechanism 82 that connects a supporting substrate 84 of the head to the vertical cursor so as to be able to move up and down. is doing. The lifting guide mechanism 82 includes a fixed link 80, rocking links 86, 88, and a lifting link 84a, and the lifting link 84a is a head support substrate 84.
Is integrally fixed to. One side of the plate-like link 86 is pivotally supported by a pivot shaft 90, 92 on a fixed link 80 fixed to the vertical cursor so as to be rotatable in a plane perpendicular to the plane of the drawing board. . One end of the link 88 is rotatably supported by the fixed link 80 by a shaft 94 in a plane perpendicular to the plane of the drawing board. The lifting link 84a fixed to the support substrate 84 is a pivot shaft parallel to the pivot shafts 90 and 92.
96 and 98 are rotatably connected to both sides of the other end of the link 86, and the lower part of the lifting link 84a is linked by a shaft 100.
It is rotatably connected to the other end of 88. Link 80,86,
88 and 84a constitute a known parallelogram link mechanism.
102 is a recess formed in the lower surface of the upper plate of the link 86 in a direction parallel to the horizontal rail 40 (see FIG. 5), and 104 is the link 86.
Is a molding hole formed in the upper plate portion of the
A screw rod 108 is arranged on the rail 102 in a direction parallel to the horizontal rail 40, and one end of the screw rod 108 is rotatably fitted in a hole 110 formed in the link 86. A plate-shaped stopper 112 is screwed in the vicinity of the other end of the screw rod 108, and a protruding end of the stopper 112 faces a side surface of the elevating link 84a. The stopper 112 is engaged with a rotation stopper (not shown). A molding 112 rotatably arranged in the hole 104 is fixed to the screw rod 108. Both side surfaces of the molding 112 slidably contact the side wall of the hole 104, and the wall surface of the hole 104 prevents the screw rod 108 from moving in its longitudinal direction. Reference numeral 114 is a piece member arranged in the recessed portion 102, and its screw hole is screwed into the screw rod 108. Both side surfaces of the piece member 108 slidably contact a guide surface of the recessed portion 102 in a direction parallel to the horizontal rail, and an upper end surface of the piece member 108 slidably elastically contacts a bottom surface of the recessed portion 102, This prevents the piece member 108 from rotating in conjunction with the rotation of the screw rod 108. The screw rod 108
The portion where the piece member 114 is screwed and the portion where the stopper 112 is screwed have a reverse screw relationship, and the rotation of the screw rod 108 causes the piece member 114 and the stopper 112 to rotate in opposite directions.
Is configured to move along. 116 is a cylindrical body whose lower end is rotatably supported on the wall surface of the cutout portion of the rising portion 80 about an axis horizontal to the drawing plate 118, and is slidably arranged in the cylindrical body 116. The cylindrical rod 120 has a coil spring 12 in a direction projecting from the cylindrical body 116.
It is urged by the elasticity of 2. The upper end projection of the rod 120 is rotatably fitted in the recess formed in the piece member 114. The screw rod 108, the knob 112, the piece member 14, and the rod 120 are connected to the link 86 by the action point of the spring 122 on the link 86.
However, the mechanism is not limited to the illustrated mechanism. Next, the operation of this embodiment will be described. When the handle of the head is grasped by hand and pulled up, the links 86 and 88 swing around the pivot shafts 90 and 92 and the shaft 94 in the counterclockwise hand rotation direction in FIG.
84a rises with respect to the drawing board surface, and the head rises in a state where it is held substantially parallel to the drawing board surface. When the hand is released from the handle at an arbitrary head raising position, the weight of the head causes a rotational torque T'to be generated in the link 86 around the pivot shafts 90 and 92 in the hour hand rotation direction in FIG. On the other hand, the piece member 114 separated from the rotation center of the link 86.
7, the elastic force of the rod 120 is applied by the elastic force of the spring 122, and this elastic force causes the link 86 to rotate counterclockwise in FIG. 7 about the rotation center of the fixed link 80. In addition, a rotational torque T for lifting the head is generated. The piece member 1 is generated by the rotational torque T ′ of the link 86 due to the weight of the head and the elasticity of the spring 122.
The magnitudes of the rotational torques T acting on the link 86 via 12 are substantially the same, and the directions of the two are opposite. Therefore, when the head is released from this, the head is almost balanced at an arbitrary raised position and does not drop by its own weight. In addition, link 88
Alternatively, the elastic force of the rod 120 may be applied in the direction in which the head floats. Next, fixed link 80 of link 86
The operation of adjusting the distance between the rotation center and the point of action of the spring 112 will be described. The screw rod 108 that rotates the molding 112 rotates. As a result, the piece member 114 moves along the guide surface of the recessed portion 102,
The other end of the rod 120 moves in the head direction on the link 86 in conjunction with the piece member 114. The movement of the piece member 114 changes the distance between the center of rotation of the link 86 and the elastic action point of the rod, that is, the radius of the link 86 as a rotational torque generating element. When the piece member 114 moves to the right in FIG. 7, the radius as the rotational torque generating element increases, which increases the counterclockwise rotational torque T of the link 86 in FIG. 7 due to the spring 122 force. , When moving to the left, the radius is reduced and the rotational torque is reduced. The value of the load W applied to the link 86 due to the weight of the head or the like changes with the change when the inclination angle in the drawing is changed. Therefore,
When the inclination angle of the drawing board is changed, the molding 112 is rotationally adjusted, so that the rotational torque T'generated on the link 86 by the load W is different from the rotational torque T'generated by the elastic force of the spring 122. The sizes of T can be matched. Corresponding to the inclination angle of the drawing board,
When the molding 112 is rotated and the screw rod 108 is rotated to adjust the rotation torque of the link 86 by the elastic force of the spring 122, the movement of the piece member 114 along the screw rod 108 is interlocked,
The stopper 112 screwed to the screw rod 108 moves in the left-right direction in the direction opposite to the piece member 114 in FIG. 7 due to the reverse screw structure of the screw rod 108. If you raise the head in parallel,
The side surface of the elevating link 84a collides with the projecting end 112a of the stopper 112, and its rise is blocked. This rising prevention position becomes lower as the stopper 112 moves to the right in FIG. That is, when the inclination angle of the drawing board is small and it is desired to generate a large rotational torque T in the link 86, the piece member 114 in FIG.
It moves rightward along the screw rod 108 to increase the distance of the piece member 114 from the rotation center of the link 86 with respect to the fixed link 80. In conjunction with the rightward movement of the piece member 114 along the screw rod 108, the stopper 112 moves leftward along the screw rod 108, and the stopper 112 separates from the side surface of the elevating link 84a. When the stopper 112 is separated from the side surface of the elevating link 84a, when the head is lifted by that amount, the side surface of the elevating link 84a is delayed and collides with the stopper 112, so that the position where the head is prevented from rising is raised. Conversely,
When the inclination angle of the drawing plate is large and steep, and a large rotating torque is not required for the link 86 and a small rotating torque is sufficient, the piece member 114 is moved to the left along the screw rod 108 in FIG. , The distance of the bridge member 114 from the center of rotation of the link 86 with respect to the fixed link 80 is reduced. The stopper 1 is interlocked with the movement of the piece member 114 to the left along the screw rod 108.
12 moves to the right along the screw rod 108, and the stopper 1
12 approaches the side surface of the lifting link 84a. When the stopper 112 approaches the side surface of the elevating link, when the head is lifted by that amount, the side surface of the elevating link 84a collides with the stopper 112 earlier, and the elevating position of the head is lowered. The rising prevention position is the mall 11
By the rotation of 2, it is automatically set to an appropriate position according to the inclination angle of the drawing board. As is clear from the above description, the screw rod 108 is rotatably supported on the lower surface of the upper plate portion of the link 86 in a direction parallel to the horizontal rail so as not to be displaced in the axial direction, and is fixed to the screw rod 108. The molded molding 112 and the piece member 114 screwed to the screw rod 108 so as not to rotate constitute a torque adjusting mechanism, and the cylindrical body 116 whose lower end portion is pivotally supported by the fixed link 80 and the cylindrical body 116 slides on the cylindrical body 116. A cylindrical rod 120 and a rod 120, which are freely fitted and whose upper end projection is rotatably fitted in a recess formed in the piece member 114.
The spring 112 for urging the head in the projecting direction constitutes a head elastic mechanism for urging the head in the ascending direction to prevent the head from falling at an arbitrary ascending position. Also, of the screw rod 108,
The portion where the piece member 114 is screwed and the portion where the stopper 112 is screwed have a reverse screw relationship, and the stopper 112 rotates in the opposite direction with respect to the piece member 114 by the rotation of the screw rod 108.
The structure which is configured to move along the axis constitutes a stopper position adjusting mechanism. [Effect] As described above, according to the present invention, the parallel rising movement range of the head is adjusted in accordance with the inclination angle of the drawing board by the stopper that sets the limit position of the head rise when the stopper surface collides with the link side. Since it is configured to obtain the head, the flying position of the head can be appropriately set, and there is an effect that efficient work can be performed.

[Brief description of drawings]

FIG. 1 is a side view of a universal parallel ruler, and shows the head connecting mechanism taken along the line AA in FIG. 2 is a side view, FIG. 3 is a plan view of the head connecting mechanism, and FIG.
7A is a side view of a universal parallel ruler, FIG. 4B is a side view of a head connecting mechanism, FIG. 5 is an overall plan view, FIG. 6 is a plan view showing another embodiment, and FIG. The drawing is a sectional side view taken along line CC, FIG. 8 is a sectional side view taken along line DD, and FIG. 9 is a side view of a universal parallel ruler. 2 …… Vertical cursor, 2a …… Fixed link, 4,6 …… Link, 8,
10 …… Axis, 12 …… Link, 14,16 …… Axis, 18 …… Head, 20 …… Board, 22 …… Stopper axis, 24 …… Drawing board, 26 ……
Link 28, Axis, 30 Slide block, 32 Coil spring, 34 Adjust screw, 40 Horizontal rail, 42 Horizontal cursor, 44 Vertical rail, 46 Vertical support device, 48 …… Ruler mounting plate, 50, 52 …… Straight ruler, 54, 56 …… Pivot bearing, 58,
60 …… Pivot bearing, 64 …… Stopper, 66 …… Guide pin, 80 …… Fixed link, 82 …… Lift guide mechanism, 84 …… Support substrate, 86,88 …… Link, 90,92 …… Pivot shaft , 96,98 ……
Pivot shaft, 100 …… Shaft, 102 …… Recessed part, 104 …… Molding hole, 108 …… Screw rod, 110 …… Hole, 112 …… Mold, 114 ……
Piece member, 116 …… Cylinder, 118 …… Axis, 120 …… Rod, 122 ……
Coil spring

Claims (2)

[Claims] 1. A horizontal rail (40) which can be fixed to a drawing board (24).
A vertical rail (44) movably connected to the horizontal rail (40) at a right angle, a vertical cursor (2) movably attached to the vertical rail (44), and a straight ruler. A head (18) to be connected, an elevating and lowering guide mechanism for connecting the head (18) to the vertical cursor (2) so that the head (18) can be moved substantially in the vertical direction, and the head (18) is urged in the ascending direction. In a device provided with a head elastic mechanism for preventing the head (18) from falling at an arbitrary raised position, one of a plurality of links (20a) (86) constituting the lifting guide mechanism. In addition, as the head (18) pivotally supported by the links (20a) (86) moves up and down, the one link (20
a) It is arranged so as to face another link (4) (84a) that is displaced in the rotational direction with respect to (86), and
The heads are arranged so that the facing distance is narrowed by the rotational displacement of the other links (4) (84a) with respect to the one link (20a) (86) as the head (18) rises. When the head (18) rises to a predetermined height, it collides with the other link (4) (84a) and sets stoppers (64) (112) for setting the upper limit position of the head (18), and the head (18). The stopper (64) (11
2) A universal parallel ruler characterized in that a stopper position adjusting mechanism for changing the facing interval with the other links (4) (84a) and changing the rising limit position of the head (18) is provided. Head lifting device. 2. A horizontal rail (40) which can be fixed to the drawing board (24).
A vertical rail (44) movably connected to the horizontal rail (40) at a right angle, a vertical cursor (2) movably attached to the vertical rail (44), and a straight ruler. A head (18) to be connected, an elevating and lowering guide mechanism for connecting the head (18) to the vertical cursor (2) so that the head (18) can be moved substantially in the vertical direction, and the head (18) is urged in the ascending direction. In a device provided with a head elastic mechanism for preventing the head (18) from falling at an arbitrary raised position, one of the plurality of links (86) forming the lifting guide mechanism is provided with The head (1
It is arranged so as to face the other link (84a) which is displaced in the rotational direction with respect to the one link (86) as the link (86) moves up and down, and the facing interval is such that the head (18) rises. The other link (84a) is arranged so as to be squeezed by the rotational displacement of the other link (84a) with respect to the one link (86), and when the head (18) rises to a predetermined height, the other link (84a). The stopper (112) that collides with the upper limit position of the head (18) to set the rising limit position of the head (18), and the other interval (84a) of the stopper (112) when the head (18) is stationary. A fixed position (80) fixed to the vertical cursor (2) side among a plurality of links forming the lifting guide mechanism is provided with a stopper position adjusting mechanism for changing the rising limit position of the head (18). ) As a fulcrum The swing link (86) is positioned between the center of rotation of the swing link (86) with respect to the fixed link (80) and the end portion on the head side, and is screwed so as not to shift in the axial direction. (108) is rotatably supported, and of the two threaded portions of the threaded rod (108) that are in a mutually reverse threaded relationship, a piece member (114) is screwed so as not to rotate around one threaded portion, The piece member (114)
Is applied to the swinging link (86) by the elastic force of the head elastic mechanism to the swing link (86) so as to float the head (18), and the screw rod ( When the stopper (112) is screwed into the other threaded portion of (108) so as not to hang around and the screw rod (108) is rotated in the forward and reverse directions, the piece member (114) and the stopper (11) are rotated.
2) moves along the screw rod (108) toward or away from each other, and the piece member (114) moves the screw rod (10).
8) along with the fixed link (80) of the rocking link (86)
When approaching the center of rotation of the rocking link (86), the rotational torque of the swinging link (86) in the head flying direction decreases, and the stopper (112) moves away from the bridge member (114) along the screw rod (108). When moved, the stopper (11
A head lifting device in a universal parallel ruler characterized in that the facing interval with respect to the other link (84a) in 2) is narrowed.