JPH0318615Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a slip-off prevention device that also serves as a scratch prevention device for the upper stile of a screen door.

[Conventional technology]

Figures 1 and 2 a and b show an overview of a first conventional example of a device for preventing the upper frame of a screen door from coming off, which also serves to prevent scratches.
and shown in Figures 3a and b.

That is, in each of these figures, the screen door 1 consists of a pair of left and right vertical frames 2, 2, a pair of upper and lower frames 3 and 4, and a screen 5 stretched between each frame. At the left and right ends of the upper stile 3, anti-slip devices 6, 6 which also serve as anti-scratch devices are provided, respectively.

As the anti-slip device 6 which also serves as a scratch preventive device, a guide groove 10 is first formed in one side plate portion 8 of the rail groove 7 of the upper stile 3 in which the rail groove 7 is formed from the upper end. . In addition, the adjustment member 12, which serves as a member to prevent slippage and also serves as a prevention member, has convex portions 14, 14 on both sides of the upper end for position regulation.
The main body part 13 has a rail groove 15 formed in the upper part thereof, a guide part 16 is provided in one side of the main body part 13, and a tapping hole 17 is formed in the lower part of the main body part 13. use

Then, the adjustment member 12 is fitted from above the upper stile 3 so that the guide portion 16 is guided into the guide groove 10, and the tapping screw 18 is inserted from the side of the upper stile 3 into the tapping hole 17 of the adjustment member 12. The screen door 1 obtained in this way by carefully tightening it and temporarily fixing it
is fitted into the window frame as is well known, and then the upper frame 19 is received in the rail grooves 7 and 15.
It is used by adjusting the adjustment member 12 up and down with respect to the rail 20, and then fully tightening the tapping screw 18. After this setting, the adjustment member 12
acts as a preventive against the rail 20, and also acts as a preventive element for the screen door 1 to come off by adjusting it up and down.

As shown in FIG. 5, an adjustment member 12 with a lowered outer side is provided as a detachment prevention device that also serves as a scratch prevention device in the second conventional example. A structure in which it is attached is also proposed.

Furthermore, a third conventional example of a detachment prevention device which also serves as a scratch prevention device is known, as disclosed in Japanese Utility Model Application Publication No. 51-74330. In this device, as shown in FIGS. 8 and 9, an adjusting member 53 is constituted by a sliding body 51 and a fixed plate 52, and an upper frame 54 having a substantially vertically elongated rectangular cylindrical shape
The fixing plate 5 is attached to the inner side 55 of the
2 is tightened, and the protruding piece 57 provided at the lower part of the fixing plate 52 is engaged with the hole 58 provided in the inner side 55, so that the fixing plate 52 is attached to the inner surface of the inner side 55. . Further, the sliding body 51
A tightening screw 60 inserted into a vertically elongated hole 59 provided at the lower part of the fixing plate 52 is tightened to the lower part of the fixing plate 52 and the inner side 55 of the upper stile 54, so that the sliding body 51 is attached to the fixing plate 52.
attached to the inside surface of the The upper part of the sliding body 51 is bent inward and stands up, and this upper part and the fixed plate 5
A rail groove 61 is formed by the upper part of 2, and a rail 62 of the upper frame is inserted into the rail groove 61.

[Problem that the invention attempts to solve]

For screen doors that use the above-mentioned anti-scratch device, it is useful when the upper frame 19 has large dimensions in the internal and external directions, that is, when the width is wide (usually 80 mm or more). In the case of a narrow width (that is, generally 80 mm or less), as shown in Figure 4, when trying to maintain the opening/closing and other functions of the shoji, the screen will inevitably extend outward. In addition, when applying mortar 21 to the entire surface of the upper frame 19 or installing frame wood, in the device of the first conventional example, it is difficult to open and close the screen door 19 depending on the protruding position of the lower surface of the upper frame 19. may be hindered. In order to prevent this, a small protrusion 22 is formed on the outer surface of the narrow upper frame 19 to indicate the limit position of the mortar 21 or the lower surface of the frame. Also, since the screen door was not set at this time, there was a risk that the above-mentioned instructions would not be followed and the above-mentioned problems such as the screen door being blocked from opening and closing would occur frequently.

As shown in FIG. 5, the adjustment member 12 of the second conventional example has the upper end of the outer plate located outside the rail groove lower than the upper end of the inner plate. Since the upper end of the upper frame 54 located outside the groove 61 is lower than the upper end of the fixed plate 52 inside the rail groove 61, when the amount of downward protrusion of mortar, etc. on the outside of the upper frame is smaller than the limit position, Although opening and closing of the screen door is not hindered, when the amount of overhang becomes large, there is a problem in that opening and closing of the screen door is hindered, similar to the device of the first conventional example.

In addition, in the devices of the first, second, and third conventional examples, the head of the screw and a part of the adjustment member protrude toward the indoor side of the upper stile, so that the dimensions of the upper stile in the inside and outside directions, that is, the width dimension, are not sufficiently adjusted. If you increase the size to provide strength, if the upper frame is narrow, the screw heads and some of the adjustment members will interfere with the shoji, making it difficult to open and close the screen door.
The screen door sometimes came off, and if the width of the upper stile was made smaller, the strength of the upper stile became insufficient, which also caused problems such as making it difficult to open and close the screen door.

Furthermore, the device of the second conventional example has the disadvantage that when a force is applied from the inside, as indicated by the arrow in Fig. 5, the attachment part is likely to be damaged due to concentrated stress, whereas the device of the third conventional example Since the adjustment member is made of two parts, the sliding body and the fixed plate, and two screws are used, the number of parts increases, it takes a long time to install it to the upper stile, and the workability during installation is not good. There was a problem.

This invention solves the above-mentioned problems; the upper stile of the screen door has sufficient strength, the screen door can be opened and closed smoothly without interfering with the shoji, and the upper stile does not require a large number of parts. The adjustment member can be firmly attached, there is less risk of damage to the adjustment member, and it is suitable for upper frames with small width dimensions in the inside and outside directions, and moreover, the lower surface of the mortar applied to the outside of the upper frame is well below the limit position. To provide a device for preventing the upper stile of a screen door from coming off, which can be easily dealt with even if the upper stile of a screen door is overhanging.

[Means for solving problems]

The device for preventing slippage of the upper stile of a screen door of this invention has a rail groove 27 formed between the outer side plate part 25 and the inner side plate part 26, and the both side plate parts 2
Engagement grooves 28 and 29 are cut in the upper edges of the grooves 5 and 26 and extend in the vertical direction, and an insertion hole 31 is bored in a part of the groove bottom 30 to form the outer and inner side plate portions of the groove bottom 30. The inner side 45 of the lower part 46 having a rectangular cylindrical cross section is suspended from an intermediate position between the upper frame 24 and the upper frame 24 having a mounting screw hole 32 formed in the inner side 45, and the upper frame 24 is fitted into the rail groove 27. The main body part 34 has an outer plate 35 and an inner plate 36 on the outer side and the inner side, respectively.
A rail groove 37 is formed between the outer plate 5 and the inner plate 36, and a break groove 38 is carved on at least one of the inner and outer surfaces of the outer plate 35.
Engagement portions 3 are inserted into the engagement grooves 28 and 29 in a planar T-shape on the outer surface of the outer plate 35 and the inner surface of the inner plate 36.
9 and 40 respectively, and the inner plate 36 is extended below the main body portion 34, so that the insertion hole 31
an adjustment member 33 that is inserted through and forms a mounting part 41, and in this mounting part 41 a long mounting hole 42 that is long in the vertical direction is formed so as to match the screw hole 32;
and engaging the engaging portions 39 and 40 of the adjusting member 33 with the engaging grooves 28 and 29 of the upper stile 24, respectively;
The attachment portion 41 of the adjustment member 33 is inserted through the insertion hole 31 of the upper stile 24, and the main body portion 34 of the adjustment member 33 is inserted through the insertion hole 31 of the upper frame 24.
is fitted into the rail groove 27 of the upper stile 24 so that the outer and inner plates 35 and 36 project outward and above the inner side plate parts 25 and 26, respectively, and the mounting screw 44 is inserted into the long hole 42 of the mounting part 41. into the screw hole 32 provided on the inner side 45 of the upper stile 24,
The mounting portion 41 is supported and fixed to the inner surface of the inner side 45.

[Effect]

This devised device for preventing the upper stile of a screen door from slipping also has a rail groove 27 provided in the upper stile 24.
The inner side 45 of the lower part 46 having a rectangular cylindrical cross section from the outer side of the groove bottom 30 and the middle position of the inner side plate parts 25 and 26.
is suspended, and the inner plate 36 of the adjustment member 33 is extended downward to form a mounting portion 41. This mounting portion 41 is inserted into the insertion hole 31 provided in the groove bottom 30, and the long hole 42 of the mounting portion 41 is inserted. The mounting screw 44 inserted into the inner side 45 is tightened into the mounting screw hole 32 provided on the inner side 45, and the mounting portion 41 is attached to the inner side 45.
By fixing it to the inner surface of the upper stile 24, the adjustment member 33 and the mounting screw 44 can be placed within the inner and outer dimensions of the upper stile 24.
It can accommodate almost the entire head of the person (see Figure 6).
The engaging portion 40 provided on the inner side plate 36 of the adjustment member 33 projects inwardly from the inner side plate portion 26 of the upper stile 24, but the amount of protrusion of the engaging portion 40 is the same as that of the first and second conventional examples. This is significantly smaller than the amount of protrusion of the heads of the screws 18, 23 and the amount of protrusion of the upper part of the sliding body 51 of the third conventional example. Therefore, while maintaining sufficient strength of the upper stile 24 without reducing the lateral dimensions of the rectangular cylindrical lower part 46 of the upper stile 24, the lateral dimensions of the entire device can be reduced, and the adjustment member 33 and the mounting Since the head of the screw 44 can be prevented from interfering with a shoji or the like placed inside the screen door, it is suitable for use in an upper frame having small dimensions in the inside and outside directions, that is, a narrow width.

Further, the outer plate 35 of the main body portion 34 of the adjustment member 33
A break-off groove 38 is carved in the main body part 34, and the upper ends of the inner side plates 35, 36 are made to protrude outside the rail groove 27 on both sides of the upper stile 24, on the inner side plate parts 25, 26, respectively. Since the break-off groove 38 is carved in the outer plate 35, when the mortar applied to the outer surface of the upper frame or the frame wood provided on the outer surface of the upper frame protrudes below the limit position, the amount of overhang can be adjusted. Even if the outer plate 35 is quite large, the upper part of the outer plate 35 is cut off and the groove 38 is cut off.
By breaking it off, the upper part of the outer panel 35 can be prevented from coming into contact with the overhanging part of the mortar, etc., making it possible to set the screen door and not hindering the opening and closing of the screen door.

Furthermore, the main body portion 34 of the adjustment member 33 is attached to the upper frame 24.
The engagement portions 39 and 40, which are planar T-shaped and protrude from the inner side plates 35 and 36 outside the rail groove 27, are fitted into the rail groove 27 and are provided on the inner side plates 35 and 36 outside the rail groove 27. Engage with the matching grooves 28 and 29, and pass the mounting portion 41 extending downward of the main body portion 34 through the insertion hole 31 of the groove bottom 30 of the rail groove 27,
Since it is supported and fixed to the inner surface of the inner side 45 provided at the lower part 46 of the upper stile 24 by means of the mounting screws 44, the number of parts is smaller than that of the third conventional example, and the number of parts is the same as that of the second conventional example. Although the installation work is easy, the adjustment member 33 can be firmly attached to the upper stile 24, and even if force is applied to the screen door from the front and back directions, the stress will not be concentrated on the attachment part of the attachment screw 44. Therefore, the setting strength of the screen door can be sufficiently increased.

〔Example〕

Hereinafter, one embodiment of the anti-removal device that also serves as a scratch preventive device for the screen door upper stile according to this invention is shown in Fig. 6, Fig. 7 a, b, c, and Fig. 8 a, b,
This will be explained in detail with reference to c.

FIG. 6 shows the entire cross section of this embodiment, FIGS. 7 a, b, and c show the side surface, cross section, and plane of the upper stile, and FIGS. 8 a, b, and c show the front side of the adjusting member. Side and plane views are shown respectively.

In each of these figures, the same reference numerals as in the conventional apparatus shown in FIGS. 2a and 2b and 3a and 3b indicate the same or corresponding parts.

As shown in Figure 7 a, b, c, the screen door upper stile 2
At the top of 4, there is a slightly low outer side plate part 25.
A rail groove 27 is formed by the inner side plate part 26 which is made higher than this, and engaging grooves 28 and 29 are cut in the vertical direction through these side plate parts 25 and 26 for engagement. An insertion hole 31 of a predetermined size is formed on one side of the groove bottom 30 of the grooves 28 and 29.
An opening is provided below the groove bottom 30 on the outside.
An inner side 45 of a lower portion 46 having a longitudinally elongated rectangular cross section is suspended from an intermediate position between the inner side plate parts 25 and 26, and a screw hole 32 is formed in this inner side 45.

Furthermore, as shown in FIG. 8a, b, and c, an adjustment member 3 made of synthetic resin such as nylon (trade name)
3 has a main body part 34 sized to fit into the rail groove 27, and on the upper part of this main body part 34,
By raising the outer plate 35 on the outer side, which has a small overall width and has an arcuate inner side, and the inner plate 36 on the inner side,
A rail groove 37 is formed between the outer and inner plates 35 and 36, and break-off grooves 38 and 38 are cut across the entire left and right direction at predetermined positions on the outer and inner surfaces of the outer plate 35. On the inner surface of the inner plate 36, engaging portions 39 and 40 having a planar T-shape to be inserted into the respective engaging grooves 28 and 29 are protruded, respectively, and below the main body portion 34, the inner plate 36 is extended to form a mounting portion 41 that is inserted into the insertion hole 31, and this mounting portion 41 includes:
A vertically long mounting hole 42 that coincides with the screw hole 32 and a setting line 43 that extends horizontally at a predetermined position are formed.

In this embodiment, the break-off grooves 38 are carved on the outside and inside surfaces of the outer plate 35, but the outer plate 35 cannot be broken off even if they are cut on only one surface. There is no problem in using it.

As shown in FIG. 6, the adjustment member 33 connects the mounting portion 41 to the insertion hole 31 of the upper stile 24 from above the rail groove 27, and engages the engaging portions 39 and 40 with each other. It is fitted into the grooves 28 and 29 respectively, and then passed through the elongated hole 42 and temporarily fastened with the mounting screw 44 in the screw hole 32 for assembly.
In this assembled state, outside the adjustment member 33, the inner plate 3
5 and 36 are the outside of the upper stile 24 and the inside plate parts 25 and 26
Each protrudes upward. The screen door 1 with the adjustment member 33 attached to the upper frame 24 as described above is fitted into the window frame, and the upper frame 1 is received into the rail grooves 27 and 37.
For example, the adjusting member 33 is adjusted up and down to the position where the setting line 43 coincides with the center of the mounting screw 44 on the rail 20 of No. 9, and then the mounting screw 44 is fully tightened. , After this setting, similar to the conventional example described above,
The inner plate 35 and the outer plate 36 of the adjusting member 33 act as a preventative against the rail 20, and also act as a preventive element for the screen door 1 to come off by adjusting the adjusting member 33 up and down.

In the case of this embodiment device, when adjusting the adjusting member 33 up and down, as described above, for example, the mortar 21 applied to the outer surface of the upper frame 19, or the frame wood applied to the outer surface of the upper frame 19, etc. When the protrusion 22 as an index protrudes below the position, the outer plate 35 corresponding to this protrusion
By breaking off the upper end at the break-off grooves 38 and 39, the setting operation can be performed without the upper end of the outer plate 35 coming into contact with the overhang, and in this set state, the main body 34 is It is fitted and held within the rail groove 27 of the upper stile 24, so that even if force is applied to the screen door 1 from the inside and outside, the stress will not be concentrated on the mounting portion of the mounting screw 44. will disappear.

[Effect of idea]

As explained above, the anti-slip device of this invention which also serves as a scratch preventive device for the upper stile for a screen door has a rail groove 27 formed between the outer side plate portion 25 and the inner side plate portion 26, and the side plate portions 25, 26, an engagement groove 28, 2 is opened at the upper edge and extends in the vertical direction.
At the same time, cut the insertion hole 3 into a part of the groove bottom 30.
1, the inner side 45 of the lower part 46 having a rectangular cylindrical cross section is suspended from the outside of the groove bottom 30 and the middle position between the inner side plate parts 25 and 26, and a mounting screw hole 32 is formed in this inner side 45. It has an upper stile 24 and a main body part 34 fitted in the rail groove 27, and an outer plate 35 and an inner plate 36 are raised on the outer side and the inner side of the main body part 34, respectively. Board 3
A rail groove 37 is formed between the outer plate 5 and the inner plate 36, and a break groove 38 is carved on at least one of the inner and outer surfaces of the outer plate 35.
Engagement portions 3 are inserted into the engagement grooves 28 and 29 in a planar T-shape on the outer surface of the outer plate 35 and the inner surface of the inner plate 36.
9 and 40 respectively, and the inner plate 36 is extended below the main body portion 34, so that the insertion hole 31
an adjustment member 33 that is inserted through and forms a mounting part 41, and in this mounting part 41 is formed a long mounting hole 42 that is long in the vertical direction so as to match the screw hole 32;
and engaging the engaging portions 39 and 40 of the adjusting member 33 with the engaging grooves 28 and 29 of the upper stile 24, respectively;
While inserting the attachment part 41 of the adjustment member 33 into the insertion hole 31 of the upper frame 24, the main body part 3 of the adjustment member 33 is inserted.
4 into the rail groove 27 of the upper frame 24, and
The inner side plates 35, 36 are on the outside, the inner side plate parts 25, 26
The mounting screws 44, which are respectively projected upward and inserted into the elongated holes 42 of the mounting portion 41, are tightened into the screw holes 32 provided on the inner side 45 of the upper stile 24, and the mounting portions 41 are attached to the inner side 45 of the upper frame 24. Since it is supported and fixed on the inner surface, the following effects can be obtained.

That is, this invention has the advantage that the outside of the groove bottom 30 of the rail groove 27 provided in the upper stile 24, the inside side plate 25,
The inner side 45 of the lower part 46 having a rectangular cylindrical cross section is suspended from the intermediate position of the inner plate 36 of the adjustment member 33.
is extended downward to form a mounting portion 41, and this mounting portion 41 is inserted into the insertion hole 31 provided in the groove bottom 30, and the mounting screw 44 inserted into the elongated hole 42 of the mounting portion 41 is inserted into the inner side 45. By tightening the mounting screw hole 32 provided in the mounting screw hole 32 provided in the upper stile 2
The adjustment member 33 and the heads of the mounting screws 44 can be almost accommodated within the external and external dimensions of No. 4 (No. 6).
(see figure). Note that the engaging portion 40 provided on the inner side plate 36 of the adjustment member 33 projects inwardly from the inner side plate portion 26 of the lower stile 24, but the amount of protrusion of the engaging portion 40 is the same as that of the first and second conventional examples. This is significantly smaller than the amount of protrusion of the heads of the screws 18, 23 and the amount of protrusion of the upper part of the sliding body 51 of the third conventional example. Therefore, while maintaining sufficient strength of the upper stile 24 without reducing the lateral dimensions of the rectangular cylindrical lower part 46 of the upper stile 24, the lateral dimensions of the entire device can be reduced, and the adjustment member 33 and mounting screws can be reduced. Since the head of 44 can be prevented from interfering with a shoji or the like placed inside the screen door, it is suitable for use in an upper frame having small dimensions in the inside-outside direction, that is, narrow width.

Further, the outer plate 35 of the main body portion 34 of the adjustment member 33
A break-off groove 38 is carved in the main body part 34, and the upper ends of the inner side plates 35, 36 are made to protrude outside the rail groove 27 on both sides of the upper stile 24, on the inner side plate parts 25, 26, respectively. Since the break-off groove 38 is carved in the outer plate 35, when the mortar applied to the outer surface of the upper frame or the frame wood provided on the outer surface of the upper frame protrudes below the limit position, the amount of overhang can be adjusted. Even if the outer plate 35 is quite large, the upper part of the outer plate 35 is cut off and the groove 38 is cut off.
By breaking it off, the upper part of the outer panel 35 can be prevented from coming into contact with the overhanging part of the mortar, etc., making it possible to set the screen door and not hindering the opening and closing of the screen door.

Furthermore, the main body portion 34 of the adjustment member 33 is attached to the upper frame 24.
The engagement portions 39 and 40, which are planar T-shaped and protrude from the inner side plates 35 and 36 outside the main body portion 34, are provided on the inner side plates 35 and 36 outside the rail groove 27. Engage with the matching grooves 28 and 29, and pass the mounting portion 41 extending downward of the main body portion 34 through the insertion hole 31 of the groove bottom 30 of the rail groove 27,
Since it is supported and fixed to the inner surface of the inner side 45 provided at the lower part 46 of the upper stile 24 using the mounting screws 44, the number of parts is smaller than that of the third conventional example, and the number of parts is the same as that of the second conventional example. Although the installation work is easy, the adjustment member 33 can be firmly attached to the upper frame 24, and even if force is applied to the screen door from the front and back directions, the stress will not be concentrated on the attachment part of the attachment screw 44. Therefore, the setting strength of the screen door can be sufficiently increased.

[Brief explanation of drawings]

Fig. 1 is a front view showing the configuration of a general screen door, Figs. 2a and 2b are a front view and a sectional view taken along line bb--b of a first conventional example of a retaining device that also serves as a scratch preventive device, and Fig. 3 is a front view showing the structure of a general screen door. Figures a and b are a front view and a side view of the adjustment member, Figure 4 is an explanatory diagram showing the conventional upper frame installation state, and Figure 5 is a second conventional example of a detachment prevention device that also serves as a scratch prevention device. 6 is a sectional view showing an embodiment of the anti-scratch device according to the present invention, and FIG. cross section and plan view,
8a, b, and c are a front view, a side view, and a plan view of the adjustment member, and FIG. 9 is a sectional view of the third conventional example;
FIG. 10 is an exploded perspective view of the adjustment member same as above. 1... Screen door, 24... Upper stile, 5... Net, 25 and 26... Outer side and inner side side plate parts, 27 and 37... Rail groove, 28, 29... Engagement groove,
30... Groove bottom, 31... Insertion hole, 32... Screw hole for mounting, 33... Adjustment member, 34... Main body, 35 and 36... Outer plate and inner plate, 3
8... Breaking groove, 39, 40... Engaging portion, 41...
...Mounting part, 42...Elongated hole for mounting, 44...Mounting screw, 45...Inner side, 46...Lower part of upper stile.

Claims (1)

[Claims for Utility Model Registration] A rail groove 27 is formed between the outer side plate portion 25 and the inner side plate portion 26, and an engagement groove 28 that opens at the upper edge of the side plate portions 25 and 26 and extends in the vertical direction. ,2
At the same time, cut the insertion hole 3 into a part of the groove bottom 30.
1, the inner side 45 of the lower part 46 having a rectangular cylindrical cross section is suspended from the outside of the groove bottom 30 and the middle position between the inner side plate parts 25 and 26, and a mounting screw hole 32 is formed in this inner side 45. It has an upper stile 24 and a main body part 34 fitted in the rail groove 27, and an outer plate 35 and an inner plate 36 are raised on the outer side and the inner side of the main body part 34, respectively. Board 3
A rail groove 37 is formed between the outer plate 5 and the inner plate 36, and a break groove 38 is carved on at least one of the inner and outer surfaces of the outer plate 35.
Engagement portions 3 are inserted into the engagement grooves 28 and 29 in a planar T-shape on the outer surface of the outer plate 35 and the inner surface of the inner plate 36.
9 and 40 respectively, and the inner plate 36 is extended below the main body portion 34, so that the insertion hole 31
An adjustment member 33 is inserted through the adjustment member 33 to form a mounting portion 41, and a long mounting hole 42 that is long in the vertical direction is formed in the mounting portion 41 so as to match the screw hole 32.
and engaging the engaging portions 39 and 40 of the adjusting member 33 with the engaging grooves 28 and 29 of the upper stile 24, respectively;
While inserting the attachment part 41 of the adjustment member 33 into the insertion hole 31 of the upper frame 24, the main body part 3 of the adjustment member 33 is inserted.
4 into the rail groove 27 of the upper frame 24, and
The inner side plates 35, 36 are on the outside, the inner side plate parts 25, 26
The mounting screws 44, which are respectively projected upward and inserted into the elongated holes 42 of the mounting portion 41, are tightened into the screw holes 32 provided on the inner side 45 of the upper stile 24, and the mounting portions 41 are attached to the inner side 45 of the upper stile 24. A slip-off prevention device that also serves as a scratch prevention device for an upper stile for a screen door, characterized in that it is supported and fixed on the inner surface.