GB2227005A

GB2227005A - Lifting/mounting panel elements

Info

Publication number: GB2227005A
Application number: GB8926349A
Authority: GB
Inventors: Yoshihisa Sugitani; Isamu Matsubara
Original assignee: Yoshida Kogyo KK
Current assignee: YKK Corp
Priority date: 1988-11-28
Filing date: 1989-11-22
Publication date: 1990-07-18
Anticipated expiration: 2009-11-22
Also published as: AU4564489A; AU629874B2; JPH02144475A; GB2227005B; BR8906219A; GB8926349D0; JPH0643755B2

Abstract

In a method for sequentially mounting panel elements (B). Fig 2, from bottom upwards wherein an upper (5) and a lower (6) lateral lever are mounted on an exterior wall (A) of a building seas to correspond to each of the panel elements (B); an upper (1) and a lower (6) hook are mounted on a back surface of each of the panel elements (B) for engagement with respective lateral levers, the improvement comprises: lifting the panel elements (B) by a lifting-guide unit (40), Fig 5; and employing joint spaces (29) between mounted panel elements as means for guiding the unit (40) in lifting operation of the panel elements (B). The unit 40 comprises ride members 40B each with rollers 53 for running up the front surface of the building and pilot/guide rollers 54 received in the joint spaces 29. <IMAGE>

Description

METHOD AND APPARATUS FOR LIFTING AND GUIDING PANEL ELEMENTS ON BUILDING SITE BACKGROUND OF THE INVENTION Field of the Invention: The present invention relates to a method and apparatus for lifting and guiding a plurality of panel elements on a building site of a building along an exterior wall of the building in mounting operation of the panel elements, which apparatus vertically travels on the exterior wall of the building to serve as a liftingguide unit for the panel elements in their mounting operation on the exterior wall of the building.

Description of the Prior Art: In cases that exterior walls of buildings get old so that their appearance deteriorates, panel elements are often mounted on the exterior walls of the buildings to renew their appearance.

Hitherto, in case that the panel elements are mounted on the exterior wall of the building to renew its appearance, a suitable scaffolding is put up around the exterior wall of the building to enable building workers to mount the panel elements on the exterior wall of the building.

On the other hand, for example, Japanese Patent Laid-Open No. 60-30743 discloses a method for mounting a plurality of curtain wall units constituting a unit curtain wall on a building body.

In the method disclosed in the Japanese Patent Laid-Open No. 60-30743, a guide rail is formed in a longitudinal member of the curtain wall unit having been mounted on the building body to enable a lifting-guide unit to vertically travel on the guide rail. Then, a new curtain wall unit to be mounted on the building is connected with the lifting-guide unit, and lifted by the lifting-guide unit along the exterior wall of the building so as to be mounted on a desired portion of the exterior wall.

However, the method for mounting the panel elements on the exterior wall of the building by employing the scaffolding put up around the building is disadvantageous in that the building workers must conduct very cumbersome work to put up the scaffolding. In addition, there is a fear that the building workers fall off of the scaffolding.

On the other hand, the method for mounting the panel elements on the exterior wall of the building according to the method for mounting the curtain wall units on the building body is disadvantageous in that the guide rail must be formed on the building site. In addition, the panel elements employed in the method are restricted in shape to special ones to make it impossible to employ flat-shaped panel elements. Furthermore, since the panel element employed in the method is provided with the guide rail, the building covered with such panel elements is poor in appearance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for lifting and guiding a plurality of panel elements along an exterior wall of a building in mounting operation of the panel elements, which apparatus vertically travels on the exterior wall of the building to serve as a lifting-guide unit for the panel elements in their mounting operation on the exterior wall of the building.

According to the present invention, the above object of the present invention is accomplished by providing: a method for mounting a plurality of panel elements on an exterior wall of a building, wherein an upper lateral lever and a lower lateral lever are mounted on the exterior wall of the building so as to correspond to each of the panel elements; an upper hook and a lower hook are mounted on a back surface of each of the panel elements, the upper hook being engaged with the upper lateral lever, the lower hook being engaged with the lower lateral lever; and the panel elements are sequentially mounted on the exterior wall of the building upward from the bottom of the exterior wall in such a manner as to permit the upper hook and the lower hook of each of said panel elements to engage the upper and the lower lateral lever of the exterior wall of the building, respectively; wherein the panel elements are lifted by a lifting-guide unit; and joint spaces are employed as means for guiding the lifting-guide unit in lifting operation of the panel elements, the joint spaces being formed between the panel elements having been mounted on the exterior wall of the building.

The above object of the present invention is also accomplished by providing: a lifting-guide unit for lifting and guiding a plurality of panel elements in mounting operation thereof on an exterior wall of a building, comprising: a main-body provided with a panel-element supporting portion, a right guide portion and a left guide portion; at least one lifting roller rotatably mounted on each said guide portion of the main body, the lifting roller being brought into contact with a front surface of each of the panel elements mounted on the exterior wall of the building while being rotatably driven by the front surface of each of the panel elements; and a pilot roller rotatably received in a joint space formed between the panel elements.

Since the present invention has the above construction, it is possible for the present invention to lift and guide the lifting-guide unit along the joint space formed between the panel elements having been mounted on the exterior wall of the building, whereby a panel element to be mounted on the exterior wall of the building is lifted and guide to its mounting area of the exterior wall of the building by use of the lifting-guide unit.

BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1 (a) - (f) are schematic views of an embodiment of the present invention, sequentially illustrating steps of the method for lifting and guiding the panel element being mounted on the exterior wall of the building; Fig. 2 is a front view of the panel elements mounted on the exterior wall of the building; Fig. 3 is a cross-sectional view of portions of the panel elements, taken along the line lll-lli of Fig. 2; Fig. 4 is a cross-sectional view of portions of the panel elements, taken along the line lV-lV of Fig. 2; Fig. 5 is a perspective view of the lifting-guide unit employed in the present invention; Fig. 6 is an enlarged perspective view of the guide portion of the lifting-guide unit shown in Fig.

5; Fig. 7 is a cross-sectional view of the guide portion of the lifting-guide unit shown in Fig. 5, in lifting operation; Fig. 8 is a cross-sectional view of a joint gasket press-fitted into the joint space formed between the panel elements; Fig. 9 is a cross-sectional view of another joint gasket press-fitted into the joint space formed between the panel elements; and Fig. 10 is a front view of a modification of the pilot roller employed in the guide portion of the lifting-guide unit shown in Fig. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinbelow, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in which: the reference character "A" denotes an exterior wall of a building; "B" a panel element; and the reference numeral 1 denotes an upper hook; 2 a lower hook; 5 an upper lateral lever; 6 a lower lateral lever; 29 a joint space formed between the panel elements "B" having been mounted on the exterior wall "A" of the building; 40 a lifting-guide unit; 53 a lifting roller employed in the lifting-guide unit 40; and 54 a pilot roller employed in the lifting-guide unit 40.

As shown in Fig. 2, a plurality of the panel elements "B" are so mounted on the exterior wall "A" of the building as to be parallelly spaced apart from each other in both of a vertical and a horizontal direction to form a clearance "t" therebetween.

Namely, as shown in Figs. 1 (d) and 2, a pair of upper hooks 1 are fixedly mounted on opposite ends of an upper portion of a back surface of the panel element "B", while a pair of lower hooks 2 are fixedly mounted on opposite ends of a lower portion of the back surface of the panel element "B".

On the other hand, a vertical mounting member 3 is fixedly mounted on the exterior wall "A" of the building through a plurality of fasteners 4 in such a manner as to span the vertical clearance "t" formed between the panel elements "B" adjacent to each other widthwise. On the vertical mounting member 3 are fixedly mounted an upper lateral lever 5 and a lower lateral lever 6 which correspond to the upper hooks 1 and the lower hooks 2, respectively, so that the upper hooks 1 engage with the upper lateral lever 5 and the lower hooks 2 engage with the lower lateral lever 6, whereby the panel element "B" is fixedly mounted on the exterior wall "A" of the building.

More specifically, as shown in Fig. 3, the panel element "B" is constructed of: a plate member 10 such as aluminum plates and the like, the plate member 10 being bent by an angle of 90 at its vertical opposite ends to form a pair of opposite bent portions 11; and a pair of edge members 12 each of which is fixedly mounted on each of the bent portions 11 of the plate member 10.

The edge member 12 is provided with a main body portion 14 in which are integrally formed a concave cavity 13 and a hook-like mounting segment 15 constituting an upper part of the edge member 12 as viewed from Fig. 3. In addition, a supporting segment 16 is integrally formed with a lower part of the main body portion 14 of the edge member 12, as viewed from Fig. 3. A through-hole 17 is formed in the bottom of the main body portion 14 of the edge member 12, in which through-hole 17 is inserted a stud bolt 18 having been fixed to a back surface of the bent portion 11 of the plate member 10. After completion of insertion of the stud bolt 18 into the through-hole 17, the stud bolt 18 is threadably engaged with a nut 19 through a suitable washer so that the edge member 12 is fixedly mounted on the bent portion 11 of the plate member 10.

As is clear from Fig. 1 (d), each of the upper hooks 1 and the lower hooks 2 of the panel element "B" assumes a plate-like shape. The upper hook 1 of the panel element "B" is provided with a concave portion 1a which opens downward. On the other hand, the lower hook 2 of the panel element "B" is also provided with a concave portion 2a opening downward. As shown in Fig. 4, each of the hooks 1, 2 is fixedly mounted on the main body portion 14 of the edge member 12 through a bolt 20 and a nut 21, the bolt 20 being inserted into the concave cavity 13 of the main body portion 14 of the edge member 12. On the other hand, the vertical mounting member 3 is provided with a base-plate portion 22 and opposite-side plate portions 23 to assume a substantially U-shaped form as viewed from Fig. 4.Each of the opposite-side plate portions 23 of the vertical mounting member 3 is provided with a vertical groove 24 which opens sideward.

In addition, each of inner corners of the vertical mounting member 3 is formed into a substantially rounded groove corner 25 as shown in Fig. 4. On the other hand, a fastener 4 is provided with a side segment portion 4a, while fixedly mounted on the exterior wall "A" of the building.

The side segment portion 4a of the fastener 4 extends in a direction perpendicular to the exterior wall "A" of the building. As shown in Fig. 4, the vertical mounting member 3 is fixedly mounted on the fasteners 4 through a plurality of bolts 26 and nuts 27, the bolts 26 having been inserted into the concave cavities 24 of the vertical mounting member 3. Incidentally, as is clear from Fig.

4, the side segment portion 4a of the fastener 4 is provided with a open groove 28 in which the bolt 26 is inserted. In mounting operation of the vertical mounting member 3 on the fasteners 4, the bolts 26 are slidably inserted into the concave cavities 24 of the vertical mounting member 3, and then slidably inserted into the open grooves 28 of the fasteners 4 to enable the vertical mounting member 3 to span a space between the fasteners 4. After that, the bolts 26 and the nuts 27 are fastened to fixedly mount the vertical mounting member 3 on the fasteners 4.

On the other hand, as shown in Fig. 3, each of the upper lateral levers 5 and the lower lateral levers 6 spans a space between the opposite-side plate portions 23 of the vertical mounting member 3, and opposite end portions of each of the upper lateral levers 5 and the lower lateral levers 6 are fixedly mounted in grooves 24 formed in the opposite-side plate portions 23 of the vertical mounting member 3.

As shown in Fig. 3, the bent portions 11 of the plate members 10 of the panel elements "B" adjacent to each other are oppositely disposed from each other through a clearance "t" which defines the joint space 29 in which is press-fitted a joint gasket 30.

As is clear from Fig. 3, the joint gasket 30 is provided with: a plurality of hollow portions 31; a plurality of tongue portions 32 provided in opposite sides of the joint gasket 30; and a pair of projections 33 oriented toward the exterior wall "A" of the building.

The pair of the projections 33 of the joint gasket 30 engage with the supporting segments 16 of the edge members 12.

Incidentally, as shown in Fig. 2, a cross-joint gasket 34 which is connected with both of the vertical and the horizontal joint gasket 30 is press-fitted in a cross portion of the clearances "t" defined between the panel elements "B" adjacent to each other.

Now, lifting and guiding operation of the panel elements "B" will be described in detail.

As shown in Fig. 1 (a), the fasteners 4 in each pair of which the fasteners 4 are horizontally spaced apart from each other by a predetermined distance are fixedly mounted on the exterior wall "A" of the building so as to be arranged in a pair of vertical rows. In each of the vertical rows, the fasteners 4 vertically adjacent to each other are vertically spaced apart from each other so as to substantially correspond to a longitudinal length of the panel element "B". The thus spaced fasteners 4 are fixedly mounted on the exterior wall "A" of the building by the building workers "C" carried by a gondola clD" .

Incidentally, the gondola "D" is vertically moved by a gondola lifting machine "F" which is mounted on a roof "E" of the building so as to be movable widthwise.

As shown in Fig. 1 (b), the vertical mounting member 3 is interposed between two rows of the fasteners 4, and fixed thereto by the building workers "D" carried by the gondola "D".

Incidentally, since the vertical mounting member 3 has a predetermined length which is generally shorter than the entire length of the exterior wall "A" of the building, it is necessary to employ a plurality of vertical mounting members 3 to cover the entire exterior wall "A". Consequently, in mounting operation of the vertical mounting members 3 on the exterior wall "A", the vertical mounting members 3 vertically adjacent to each other are connected with each other through a pair of connecting pins each of which is inserted into the rounded groove corners 25 of both of the vertically adjacent vertical mounting members 3 on which the upper lateral levers 5 and the lower lateral levers 6 have been fixedly mounted.

As described above, since the upper lateral levers 5 and the lower lateral levers 6 for supporting the panel elements "B" are fixedly mounted on the exterior wall "A" of the building through the vertical mounting members 3 and the fasteners 4, but are not directly mounted on the exterior wall "A", it is possible to precisely position the upper lateral levers 5 and the lower lateral levers 6 at predetermined locations even when the exterior wall "A" of the building is provided with some projections and cavities.

As shown in Fig. 1 (c), the panel element "B" to which the upper hooks 1 and the lower hooks 2 have been fixed in such a manner as to be illustrated in Figs.

3 and 4 is mounted on the lifting-guide unit 40. After that, the lifting-guide unit 40 is lifted along the exterior wall "A" of the building, while guided by the joint space 29 formed between the panel elements "B" having been fixedly mounted on the exterior wall "A" of the building so that the panel element "B" mounted on the lifting-guide unit 40 is vertically lifted by the unit 40 along the joint space 29.

As shown in Fig. 5, the lifting-guide unit 40 is provided with a main body portion 40a and a pair of opposite guide portions 40b.

In the main body portion 40a of the lifting-guide unit 40, an intermediate lateral member 42 and a lower lateral member 43 are interposed between a pair of opposite vertical members 41. Oppositely disposed from the intermediate lateral member 42 is a supporting lateral member 44 which cooperates with the intermediate lateral member 42 to form a panel element supporting portion 45 of the lifting-guide unit 40. The intermediate lateral member 42 is supported by a pair of opposite lateral projections 46 of the opposite vertical members 41. Each of the opposite lateral projections 46 is provided with a bracket 47 on which a holding member 48 is mounted so as to be rotatable in a horizontal plane. A locking pin 49 is provided in an upper portion of each of the vertical members 41, while a locking hole 50 is provided in each of the holding members 48.In mounting operation of the panel element "B" on the lifting-guide unit 40, after the panel element "B" is put on the lifting-guide unit 40, the holding members 48 are horizontally rotated to abut on opposite end portions "B1,, of a front surface of the panel element "B", and then the locking pins 49 of the vertical members 41 are so actuated as to enter the locking holes 50 of the holding members 48 under the influence of springs (not shown), so that the panel element "B" is firmly held in a vertical condition in the lifting-guide unit 40.

On the other hand, as shown in Fig. 5, in the opposite guide portions 40b of the lifting-guide unit 40, a vertical plate 51 is fixed to each of the vertical members 41, to which vertical plate 51 is fixed a mounting post 52 on which rotatably mounted are the lifting rollers 53 and the pilot rollers 54. More specifically, as viewed from Fig. 6, the lifting rollers 53 are mounted in opposite sides of the mounting post 52 so as to be arranged in rows. A supporting axle 53a of the lifting roller 53 horizontally extends in a direction perpendicular to the vertical member 41. An outer peripheral surface of the lifting roller 53 is covered with a rubber member so that the lifting roller 53 constitutes a rubber roller.

On the other hand, as viewed from Fig. 6, the pilot rollers 54 are rotatably mounted on an upper portion, an intermediate portion and a lower portion of a front surface of the mounting post 52. A supporting axle 54a of the pilot roller 54 horizontally extend outward from the front surface of the mounting post 52 in a direction perpendicular to the front surface of the mounting post 52. The pilot roller 54 has an outer diameter slightly smaller than the clearance "t". More specifically, as viewed from Fig. 6, each of the pilot rollers 54 mounted on the upper and the lower portion of the front surface of the mounting post 52 is slightly smaller in outer diameter than the pilot roller 54 mounted on the intermediate portion of the front surface qf the mounting post 52, and thereby enters the joint space 29 more easily than the intermediate pilot roller 54.

As shown in Fig. 5, the upper hooks 1 of the panel element "B" mounted on the lifting-guide unit 40 are connected with a lifting beam 57 through a chain 55 and a lever chain block 56, while the opposite vertical members 41 of the lifting-guide unit 40 are connected with opposite sides of the lifting beam 57 through lifting-guide suspension ropes 58. The lifting beam 57 is vertically moved by the lifting-guide unit hoist "G", while provided with a pair of guide rollers 59.

Consequently, in mounting operation the panel element "B" on the lifting-guide unit 40 having the above construction, first of all, the locking pins 49 of the opposite vertical members 41 are drawn from the locking holes 50 of the holding members 48 to permit the holding members 48 to rotate outward. Under such circumstances, the panel element "B" is so put on the intermediate lat eral member 42 as to abut on the supporting lateral member 44. After that, the holding members 48 are rotated inward to abut on the opposite side portions B1 of the panel element "B", and then the locking pins 49 of the vertical members 41 are inserted into the locking holes 50 of the holding members 48 so that the panel element "B" is firmly mounted on the main body portion 40a of the lifting-guide unit 40. The upper hooks 1 of the thus mounted panel element "B" are then connected with the lifting beam 57.On the other hand, the pilot rollers 54 of the lifting-guide unit 40 are inserted into the joint space 29 of the panel elements "B" having been mounted on the exterior wall "A" of the building. The lifting rollers 53 of the lifting-guide unit 40 abut on the panel elements "B" having been mounted on the exterior wall "A", to prevent the main body portion 40a of the unit 40 from interfering with the panel elements "B having been mounted on the exterior wall "A" of the building. The pilot rollers 54 guide the lifting-guide unit 40 vertically along the joint space 29 to stabilize the unit 40 widthwise in lifting operation thereof.

As shown in Fig. 1 (d), when the panel element "B" mounted on the lifting-guide unit 40 reaches a position above the top one of the panel elements "B" having been mounted on the exterior wall "A" of the building1 the panel element "B" mounted on the unit 40 is disengaged from the unit 40 and drawn toward the exterior wall "A".

After that, as shown in Fig. 1 (e), the upper hooks 1 and the lower hooks 2 of the panel element "B" thus disengaged abut on the upper lateral lever 5 and the lower lateral lever 6, respectively.

Under such circumstances, the lever chain blocks 56 unwind the chains 55 to vertically move the panel element downward to cause the upper hooks 1 and the lower hooks 2 to receive the upper lateral lever 5 and the lower lateral lever 6 in their concave portions la and 2a, respectively, whereby the panel element "B" thus disengaged from the lifting-guide unit 40 is fixedly mounted on the exterior wall "A" of the building.

As described above, in lifting and guiding operation of the panel element "B", since the lifting-guide unit 40 is lifted along the panel elements "B" having been mounted on the exterior wall "A" to cause the lifting rollers 53 and the pilot rollers 54 to rotatably move along surfaces of the panel elements "B", there is a fear that these rollers 53, 54 damage the surfaces of the panel elements "B" having been mounted on the exterior wall "A" of the building. As shown in Fig. 7, in order to prevent the panel elements "B" from being damaged by these rollers 53, 54 of the lifting-guide unit 40 in lifting and guiding operation thereof, a pair of cured sheets 60 of synthetic resin or a pair of aluminum sheets are employed to cover the plate members 10 and their bent segments 11.As is clear from Fig. 7, the cured sheets 60 prevent the surfaces of the panel elements "B" mounted on the exterior wall "A" of the building from being damaged by the rollers 53, 54 of the liftingguide unit 40. After completion of mounting operations of the panel elements "B" on the exterior wall "A" of the building, the cured sheets 60 are removed from the panel elements "B", and the joint gaskets 30 are pressfitted in the joint spaces 29 formed between the panel elements "B" mounted on the exterior wall "A" of the building.

In one of the edge members 12 or in the right one of the edge members 12 as viewed from Fig. 8, it is also possible to eliminate the supporting segment 16 of the edge member 12. In this case, the left one of the edge members 12 has an engaging projection 16a of its supporting segment 16 inserted into an engaging groove 30a of the joint gasket 30 as shown in Fig. 8.

In addition, as shown in Fig. 9, it is also possible for the right one of the edge members 12 as viewed from Fig. 9 to have a concave groove 16b in its supporting segment 16. In this case, an additional gasket 61 is press-fitted in the concave groove 16b of the supporting segment 16 of the right edge member 12 as viewed from Fig. 9, while brought into a close contact with an additional engaging projection of the supporting segment 16 of the left edge member 12, which additional engaging projection extends in a direction counter to the extending direction of the engaging projection 16a. As a result, as shown in Fig. 9. the joint space 29 formed between the panel elements "B" is double-sealed by the joint gasket 30 and the additional gasket 61.

On the other hand, as shown in Fig. 10, it is also possible for the plate member 10 of the panel element "B" to have its edge portion 10a extend widthwise beyond the edge member 12. In this case, the pilot roller 54 is so modified as to have an intermediate small-diameter portion 54b which is brought into contact with the edge portion 10a of the plate member 10 of the panel element "B" to stabilize the lifting-guide unit 40 in its lifting and guiding operation, whereby the unit 40 is prevented from vibrating in a direction perpendicular to the exterior wall "A" of the building.

In the method and apparatus of the present invention having the above constructions, since the panel element "B" is lifted by the lifting-guide unit 40 which travels on the line of the joint space 29 formed between the panel elements "B" having been mounted on the exterior wall "A" of the building, it is not necessary for the panel element "B" to assume a specialized shape. In addition, it is also possible for the panel element "B" to have a flat front surface which improves the exterior wall "A" of the building in appearance.

In addition, according to the present invention, since the upper hooks 1 and the lower hooks 2 of the panel element "B" engage with the upper lateral lever 5 and the lower lateral lever 6 respectively to fixedly mount the panel element "B" on the exterior wall "A" of the building, it is possible to fixedly mount the panel element "B" on the exterior wall "A" of the building in a simple manner.

Since the lifting-guide unit 40 is provided with the opposite guide portions 40b having the pilot rollers 54 received in the joint space 29, it is possible to prevent the unit 40 from vibrating widthwise in lifting and guiding operation thereof.

Since the above description refers to the preferred embodiments only, it should be understood that those skilled in the art could accomplish modifications within the scope of the present invention and accordingly, the present invention should be measured from the following claims.

Claims

1. A method for mounting a plurality of panel elements (B), wherein an upper lateral lever(5) and a lower (6) lateral lever are mounted on an exterior wall (A) of a building so as to correspond to each of said panel elements (B); an upper hook (1) and a lower hook (2) are mounted on a back surface of each of said panel elements (B), said upper hook (1) being engaged with said upper lateral lever (5), said lower hook (2) being engaged with said lower lateral lever (6); and said panel elements (B) are sequentially mounted on said exterior wall of said building upward from the bottom of said building in such a manner as to permit said upper hook (1) and said lower (2) hook of each of said panel elements (B) to engage said upper lateral lever (5) and said lower (6) lateral lever of said exterior wall of said building, respectively wherein said panel elements (B)areliftedbyalifting-guide unit (40); and joint spaces (29) are employed as means for guiding said lifting-guide unit (40) in lifting operation of said panel elements (B), said joint spaces (29) being formed between said panel elements (B) having been mounted on said exterior wall (A) of said building.

2. A lifting-guide unit for lifting and guiding a plurality of panel elements (B) in mounting operation thereof on an exterior wall (A) of a building, comprising: a main-body (40a) provided with a panel-element supporting portion (45), a right guide portion and a left guide portion (40b); at least one lifting roller (53) rotatably mounted on each said guide portion (40b) of said main body (40a), said lifting roller (53) being brought into contact with a front surface of each of said panel elements (B) mounted on said exterior wall (A) of said building while being rotatably driven by said front surface of each of said panel elements (B); and a pilot roller (54) rotatably received in a joint space (29) formed between said panel elements (B).