GB2090550A

GB2090550A - A method for producing a railing or the like

Info

Publication number: GB2090550A
Application number: GB8138180A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-12-19
Filing date: 1981-12-18
Publication date: 1982-07-14
Also published as: SG70085G; GB2090550B; MY8600316A; KR870001264B1; KR830007210A; HK87386A

Abstract

A method for producing a railing or the like which comprises a horizontal bar (1) and a vertical bar (4). The horizontal bar (1) and the vertical bar (4) are interconnected by arranging for a vertical bar connecting part (2) of the horizontal bar (1) to be gripped or pinched between an outer protrusion (5) and an inner protrusion (14) formed on the vertical bar (4). The inner protrusion (14) is formed by plastic press working such as swelling, bending and rib-forming. <IMAGE>

Description

SPECIFICATION % A method for producing a railing or the like The present invention relates to a method for producing a railing or the like which comprises a horizontal bar and a vertical bar which are to be connected to each other.

In the prior art, interconnection of the horizontal bar and the vertical bar has been achieved generally by welding or screw-fastening. However, in the case of welding, a careful operation by a skilled worker is required in order to obtain enough strength to assure adequate safety from the resulting railings.

The cost of assembly of railings using welding must inevitably be high because the wages of such a skilled worker are correspondingly high. In addition, by depending on a welding operation, the materials available for the horizontal and vertical bars must be limited to weldable materials. On the other hand, in the case of screw-fastening, although skilled workers are not required, there occurs a different problem that the vertical bar tends to become loose or to fall off as a result of eventual screw-loosening. Furthermore, especially in the case of a window lattice, screw-fastening is disadvantageous for the prevention of crimes, because the vertical bar may be easily detached. For solving the above problems, it is required to add preventive measures against screw-loosening.Therefore, assembling or connecting work becomes more troublesome, and it is not easy to increase the assembling efficiency.

It is a principle object of the present invention to provide a manufacturing method which does not depend on any handwork of the skilled worker, such as a welder, an in which the strong and safe, assembly of the horizontal bar with the vertical bar can be achieved efficiently.

In accordance with the present invention, there is provided a method for producing a railing or the like which includes at least one horizontal bar and one vertical bar, the method comprising forming a first outer protrusion on the vertical bar, inserting the vertical bar into a hole formed on a vertical bar connecting part of the horizontal bar, forming a second, inner protrusion on the vertical bar by plastic working such as swelling, rib-forming and bending operations, and gripping or pinching the vertical bar connecting part of the horizontal bar between the inner protrusion and the outer protrusion so as to interconnect the horizontal bar and the vertical bar.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings, in which: Figs. 1 to 7 show a first embodiment of the present invention using a semicylindrical pipe as a horizontal bar of a railing.

Figure 1 is a vertical section view of the horizontal bar; Figure 2 is a plan view of the horizontal bar; Figure 3 is a horizontal section view of a vertical bar of the railing; Figure 4 is a right side view of the vertical bar; Figure 5 is a vertical sectional view of a lower part of the railing in which the horizontal and vertical bars are not interconnected yet by a connecting press device inserted thereinto; Figure 6 is a vertical sectional view of the lower part of the railing in which the horizontal and vertical bars are already interconnected by the device; and Figure 7 is a vertical sectional view of the lower part of the railing from which the device is already drawn.

Figures 8 to 13 show a second embodiment of the present invention using a circular pipe as a horizontal bar of a railing.

Figure 8 is a vertical sectional view of a lower part of the railing in which a vertical bar has not been inserted into the horizontal bar; Figure 9 is a vertical sectional view of the lower part of the railing in which the vertical bar has already been inserted into the horizontal bar; Figure. 10 is a vertical sectional view of the lower part of the railing in which the vertical bar and the horizontal bar are interconnected; Figure 11 is a sectional view taken along a line A-A' of Fig. 8; Figure 12 is a sectional view taken along a line B-B' of Fig. 9; and Figure 13 is an enlarged vertical sectional view of the lower part of the railing from which a connecting device has already been drawn.

Figures 14 to 19 show further embodiments of the present invention each differing in the horizontal sectional shape of the bars.

Figure 14 is a vertical view of a railing in which a horizontal bar is made of a square pipe, while a vertical bar is made of a circular pipe; Figure 15 is a sectional view taken along the line C-C' of Fig. 14; Figure 16 is a vertical view of a railing in which a horizontal bar is made of a circular pipe, while a vertical bar is made of a square pipe; Figure 17 is a sectional view taken along the line D-D' of Fig. 16; Figure 18 is a vertical view of a railing in which both a horizontal bar and a vertical bar are made of a square pipe; and Figure 19 is a sectional view taken along the line E-E' of Fig. 18.

Figures 20 to 24 show another embodiment of the present invention using a longitudinally ribbed pipe as a vertical bar of a railing.

Figure 20 is a perspective view of the vertical bar in which end portions of the rib are cut off; Figure 21 is a vertical sectional view of a lower part of the railing in which the vertical bar has not yet been connected to a horizontal bar; Figure 22 is a vertical view of the lower part of the railing in which the horizontal bar and the vertical bar are already interconnected; Figure 23 is a vertical sectional view of a lower part of the railing in which a horizontal bar and a vertical have not yet been interconnected by the connecting press device; and Figure 24 is a vertical sectional view of the lower part of the railing in which the horizontal bar and the vertical bar are already interconnected.

Figures 25 to 28 show a further embodiment of the present invention using a flanged tubular cover as a vertical bar of a railing.

Figure 25 is a plan view of the cover; Figure 26 is a front view, partially shown in vertical section, of the vertical bar in which the covers are fitted on an upper end and a lower end of the vertical bar; Figure 27 is a vertical sectional view of the railing in which the upper cover is inserted into a hole of a vertical bar connecting plate of an upper horizontal bar, while the lower cover is inserted into a hole of a lower horizontal bar; Figure 28 is a vertical sectional view in which the vertical bar has already been connected to the upper and lower horizontal bars, and the vertical bar connecting plate is assembled with the horizontal bar body.

Figures 29 to 32 show another embodiment of the present invention using a hollow pipe as a horizontal bar of a railing.

Figure 29 is a vertical sectional view of a lower part of the railing in which a flanged tubular cover fitted on a lower end of a vertical bar is inserted into a hole of the lower horizontal bar; Figure 30 is a vertical sectional view of the lower part of the railing in which the vertical bar has already been connected with the horizontal bar; Figure 31 is a vertical sectional view of the lower part of the railing in which one of two press die pieces is drawn from the horizontal bar; and Figure 32 is a right side view, partially shown in vertical section, of the completed railing in which all of the press die pieces are removed.

Figures 33 to 38 show a further embodiment of the present invention using a hollow pipe has a horizontal bar of a railing.

Figure 33 is a vertical view of a lower part of the railing in which a sectional die composed of a first press die and a second press die is inserted into the horizontal bar; Figure 34 is a vertical sectional view of the lower part of the railing in which a flanged tubular cover fitted on a lower end of a vertical bar has already been inserted into the horizontal bar; Figure 35 is a vertical sectional view of the lower part of the railing in which the vertical bar is already connected with the horizontal bar; Figure 36 is a sectional view taken along the line F-F' of Fig. 33; Figure 37 is a sectional view taken along the line G-G' of Fig. 34; Figure 38 is a right side view, partially shown in vertical section, of the railing in which all of the press die pieces are already removed.

Figure 39 shows a further embodiment of the present invention using a circular pipe as a horizontal bar of a railing.

Figure 40 is a vertical sectional view of a lower part of the railing in which a vertical bar is connected to the horizontal bar.

Figure 41 is a plan view of another flanged tubular cover.

Figure 42 is a vertical section view of the cover of Fig. 41.

Figure 43 is a plan view of a further flanged tubular cover.

Figures 44 to 47 show another modification of the present invention.

Figure 44 is a vertical sectional view of a railing in which a vertical bar has not yet been connected to a vertical bar connecting plate of an upper horizontal bar and to a lower horizontal bar; Figure 45 is a vertical sectional view of the railing in which all of press die pieces are removed; Figure 46 is a vertical sectional view of a railing in which an other connecting press device is used; and Figure 47 is a vertical sectional view of a railing in which a further connecting press device is used.

Referring to the embodiment of the present invention shown in Figs. 1 to 7, a vertical bar connecting part of a horizontal bar 1 has a circular arc section, so that the horizontal bar 1 is of semicylindrical section as a whole. As shown in Fig. 2, a plurality of circular holes 3 for receiving respective vertical bars 4 are formed on the vertical bar connecting part 2 at predetermined longitudinally spaced locations. As shown in Fig. 4, an outwardly extending circular flange formed on the side wall of the vertical bar'4 has a curved surface 5a conformed to an outer surface 2a of the vertical bar connecting part 2, so that the whole of the surface 5a may snugly engage the outer surface 2a when the bar 4 is inserted into one of the holes 3.

In order to firmly attach the vertical rod 4 to the horizontal bar 1, an operating rod 7 is driven by an oil hydraulic machine or the like in the direction of the arrow in Fig. 5, while restraining by a suitable means both the vertical bar 4 and a body casing 6 of a connecting device from any movement, whereby to push towards a side wall 11 of the body casing 6 a core piece 9 as a result of cooperative action between a cam surface 8 on the operating rod 7 and a cam surface 10 on the core piece 9.

This action is arranged to cause an outwardly protrudirig part 12 of the core piece 9 to be projected through a lateral hole 13 in the side wall 11 whereby to press outwardly a portion of the side wall of the vertical bar 4 so as to form an enlarged or ribbed portion 14 of angled section while leaving an adequate length up to an end portion 4a, as shown in Fig. 6. When the operating rod 7 is subsequently driven downwardly, each core piece 9 is moved inwardly as a result of the resilience of a curved leaf spring 15 interposed between an inner surface of the vertical bar 4 and an outer surface of the core piece 9, so that each protruding part 12 is withdrawn within the lateral hole 13.Thus, the body casing 6 of the connecting device can be withdrawn from the vertical bar 4 so as to achieve the configuration shown in Fig. 7 wherein the enlarged portion 14 contacts an inner surface 2b of the vertical bar connecting part 2, and the vertical bar connecting part 2 is gripped between the curved outer protrusion 5 and the enlarged portion 14 to firmly attach the parts 1 and 4 together. The enlarged portion 14 constitutes an "inner protrusion".

In the case of the embodiment shown in Figs. 8 to 13, a horizontal bar 1 comprises a completely circular pipe. A sectional die for forming an inner protrusion comprises a first die member 16 and a second die member 17 which supports the first die member 16. A frusto-conical guide boss 19 and an annular guide groove 18 for receiving an end portion 4a of a vertical bar 4 are formed on an upper surface 1 6a of the first die member 16. A cam 20 is formed on a lower surface 1 6b of the first die member 16, and a cam 21 is formed on an upper surface 1 7a of the second die member 17. The sectional die is smoothly inserted into the horizontal bar 1 by engaging a slanting cam surface 20a of the cam 20 with a slanting cam surface 21a of the cam 21 and by engaging the lower surface 1 6b of the first die member 16 with the upper surface 1 7a of the second die member 17.

With the guide boss 19 positioned to confront a hole 3 of the horizontal bar 1, the first die member 16 is restrained from longitudinal movement, while the second die member 17 is driven longitudinally in the direction of the arrow in Fig. 11. Thus, the first die member 16 is pushed diametrically owing to the cooperation between the slanting cam surfaces 20a and 21d, so that the guide boss 19 enters the hole 3. In this condition, because the top surface 20b of the cam 20 of the first die member 16 contacts the upper surface 1 7a of the second die member 17, the cross section of the sectional die is enlarged to its maximum value.

The end portion 4a of the vertical bar 4 is then inserted into the annular groove 18 through a space between the guide boss 19 and the hole 3. The end portion 4a is arranged to be bent outwardly to form a circular flange 23 by pressing the vertical bar 4 onto the first die member 16 by driving a movable press die 22 downwardly, as viewed in Fig.

12. The resulting circular flange portion 23 constitutes an inner protrusion, and grips or pinches the vertical bar connecting part 2 of the horizontal bar 1 in cooperation with the outer protrusion 5 in order to firmly connect the vertical bar 4 to the horizontal bar 1.

In the method of assembly described above, the vertical bar 4 having the outer protrusion 5 is inserted into the hole 3 formed in the vertical bar connecting part 2 of the horizontal bar 1 with the outer protrusion 5 remaining outside the horizontal bar 1, and the inner protrusion 14 or 23 is then formed on the vertical bar 4 inside the horizontal bar 1, so as to connect the vertical bar 4 to the horizontal bar 1 by gripping or pinching the vertical bar connecting part 2 between the inner protrusion 14 or 23 and the outer protrusion 5.

Therefore, the present method of assembling the horizontal bar and the vertical bar can be performed efficiently without the necessity for a highly paid skilled worker, because the outer protrusion and the inner protrusion can be easily formed by simple pressing operations such as beading, flanging, flaring, curling, rib-forming, swelling, expanding and the like, and because pinching or pressing of the vertical bar connecting part 2 is done simultaneously with the forming of the inner protrusion 14 or 23.

Furthermore, since the vertical bar 4 and the horizontal bar 1 are interconnected by pinching with a pressing machine, the vertical bar 4 seldom becomes rickety and falls off.

Accordingly, it is easy to provide a railing or the like which can fulfill safety requirements and standards. Furthermore, the railing or the like produced by the present invention is useful in the prevention of crime, because the vertical bar 4 cannot be detached without cutting the outer protrusion 5 and the vertical bar connecting part 2.

In the case of the above embodiments, because the curved surface 5a of the outer protrusion 5 is conformed to the curved outer surface 2a of the vertical bar connecting part 2, the vertical bar 4 cannot be rotated in the hole 3 of the horizontal bar 1, when the outer protrusion 5 has been fitted on the vertical bar connecting part 2. This rotation preventing function resulting from the fit between the part 2 and the protrusion 5 is fully obtained even if pinching or fastening of the part 2 by the inner and outer protrusions is itself relatively slack.Accordingly, there is no fear of paint peeling off or of the connection becoming rusty or of erosion of base metal surfaces owing to rotation of the vertical bar, so that the interconnection condition of the horizontal and vertical bars of the railing or the like can be maintained over long periods without deterioration.

The present invention can be embodied in different forms. There is no limitation to the sectional shape and the number of horizontal or vertical bars, to the sectional shape and the number of the inner or outer protrusions, and to the interconnection angle between the horizontal and vertical bars. Furthermore, the method for forming the inner or outer protrusions is not limited to the embodiments shown in Figs. 1 to 13.

For example, as shown in Figs. 14 and 15, the horizontal bar may be made of a pipe of square section, while the vertical bar is made of a pipe of circular section. On the other hand, the horizontal bar may be made of a circular pipe, while the vertical bar is made of a square pipe. Furthermore, both the horizontal bar and the vertical bar may be made of a square pipe.

If a noncircular pipe is used as the vertical bar, it is desirable on production and assembly to make an end portion of the pipe cylindrical by pressing operations and to form the outer protrusion on the cylindrical end portion, as shown in Figs. 16 and 18. Although it is desirable for assurance of connection strength that the inner and outer protrusions comprise an annularly continuous flange or rib, the protrusions may be a group of bosses or projections which are disposed annularly but noncontinuously, and further may be a single boss or projection, depending on the nature of the material used for the bars and on the thickness of the protrusions.

In the case of the above embodiments, because the enlarged or ribbed portion 14 constituting the inner protrusion is formed on the side wall of the vertical bar 4 while leaving an adequate length up to the end portion 4a, and has an angled section in which one slanting segment leans against the other reversely slanting segment, the enlarged portion 14 is strong enough to bear the inward bending force or the collapsing force, so that the connection strength of the horizontal and vertical bars is considerably increased in comparison with the flanged or flared portion 23 formed on the opening end portion 4a. Therefore, it is easy to provide a railing or the like which is superior in safety.

In the embodiments shown in Figs. 20 to 24, a vertical bar 4 is constituted by a pipe having a plurality of longitudinal ribs 24.

Holes 3 formed on a vertical bar connecting part 2 of a horizontal bar 1 conform to the shape of the vertical bar body without the ribs 24. End portions 24a of the ribs 24 are cut off by a suitable means as shown in Fig. 20.

The remaining portion 24b of each rib 24 engages the outer surface 2a of the vertical bar connecting part 2 at its end face 24c.

Thus, the remaining portions 24a of the ribs 24 constitute the outer protrusion of the present invention.

As shown in Fig. 21, a body casing 6 of a connecting device is fitted into the end portion of the vertical bar 4 which is inserted into the horizontal bar 1. When an operating rod 7 is driven in the direction-of the arrow in Fig.

21 by an oil hydraulic machine or the like while restraining by a suitable means the vertical bar 4 and the body casing 6 against any movement, each core piece 9 is pushed towards a side wall 11 of the casing 6 as a result of the cooperative action of a cam surface 8 on the operating rod 7 and a cam surface 10 on the core piece 9. By this means, a protruding part 12 on the core piece 9 projects out of a lateral hole 13 in the side wall 11 and a side wall of the vertical bar 4 is pressed outwardly, so that there is formed an enlarged or ribbed portion 27 of angled section, while leaving an adequate length up to the end face of the bar 4.

The enlarged portion 27 constitutes the inner protrusion of the present invention, and pinches or fastens the vertical bar connecting part 2 between itself and the remaining portions 24b of the ribs 24, so that the vertical bar 4 may not be withdrawn or moved.

In the embodiment shown in Figs. 23 and 24, a movable die member 25 having a tapered surface 26 is fitted into an end portion 4a of the vertical bar 4. The end portion 4a is arranged to be bent outwardly by the tapered surface 26 so as to form a flanged portion 28 when the die member 25 is driven in the direction of the arrow in Fig. 23 while both the vertical bar 4 and the horizontal bar 1 are held stationary by a suitable means. The flanged portion 27 constitutes the inner protrusion of the present invention.

In the case of the embodiments shown in Figs. 20 to 24, the outer protrusion is not one that is obtained by plastic working such as shear spinning, heading, drawing, and stretchdrawing which necessarily weakens the structure of the protrusion and the vertical bar body. The outer protrusion of the present embodiment is constituted by the remaining body portions 24b of the ribs 24 formed on the vertical bar 4 obtained by cutting off the end portions 24a of the ribs 24. The present outer protrusion is superior in structural strength in comparison with such protrusions as are formed by plastic working.

Furthermore, because both the enlarged portion 27 and the flanged portion 28 constitutes the inner protrusion are formed on a part of the vertical bar 4 to which the above mentioned plastic working by press machines is not done, the inner protrusion of the present embodiment is superior in structural strength in comparison with such protrusions as are formed on the part of the vertical bar which is weakened as a result of the plastic working.

In this way, since each of the inner and outer protrusions is formed without weakening their structures and the vertical bar, the strength of the connection between the horizontal and vertical bars is considerably increased. Furthermore, because the portions 24b of the ribs 24 acts as a reinforcing member for the vertical bar 4, it is easy to provide a railing or the like which is of superior structural strength.

In the case of the embodiments shown in Figs. 25 to 43, a tubular cover 29 is fitted on an end portion 4a of a hollow vertical bar 4, and an end portion 30 of the cover 29 is inserted into a hole 3 formed on a vertical bar connecting part 2 of a horizontal bar, and is then bent outwardly together with the end portion 4a of the vertical bar 4 so as to press or pinch the vertical bar connecting part 2 in cooperation with a flanged portion 31 formed on the bottom end of the cover 29.

The cover 29 has a coaxial inner tube 32, which is fitted into the end portion 4a of the vertical bar. After a ringed end segment 33 is brought into engagement with the end face of the vertical bar 4, the end portion 4a of the bar 4 is fastened to the inner tube 32 and the cover body 39 by press working.

As shown in Fig. 27, the flanged portion 31 of the cover 29 is caught between a first press die member 34 and the vertical bar connecting part 2 of the horizontal bar 1, and then a second press die member 35 having a tapered surface 36 is moved into the inner tube 32. In this way, both the end portion 30 and the inner tube 32 of the cover 29 are bent outwardly together with the end portion 4a of the bar 4 so as to become the inner protrusion of the present invention. With respect to the upper hollow horizontal bar 1, the vehicle bar connecting part 2 is constituted by a separate plate. As shown in Fig. 28, the plate 2 is fitted into receiving grooves 37 formed on the horizontal bar body 1 after connecting the vertical bar 4 to it. Thus, assembly of a railing is completed.

In the case of the embodiment shown in Figs. 29 to 32, because a vertical bar connecting part 2 cannot be detached from a horizontal bar body 1, a sectional die device is used. A first die member 38 having an annular guide groove 40 and a guide boss 41 is supported by a second die member 39 so as to engage with inner surface of the horizontal bar 1. The end portion 30 of the cover 29 is inserted into the guide groove 40. When the cover 29 and the vertical bar 4 are pressed against the first die member 38 by the engagement of a movable die member 41 with the flanged portion 31 of the cover 29, both the end portion 30 and the inner tube 32 are outwardly bent together with the end portion 4a of the bar 4, as shown in Fig. 30.When the second die member 39 is withdrawn from the horizontal bar 1 after the bending operation, the first die member 38 is first moved downwardly so that the bent cover 29 may get out of the guide groove 40 and the guide boss 41 may also get out of the hole 3. Thus, the first die member 38 can be drawn out of the hollow horizontal bar 1.

In the case of the embodiment shown in Figs. 33 to 38, a sectional die is comprised by a first die member 43 and a second die member 44 which supports the first die member 43 thereon. The sectional die is inserted into a hollow horizontal bar 1 so that a cam surface 45 formed on the lower surface of the first die member 43 contacts a cam surface 46 formed on the upper surface of the second die member 44, namely, at the most contracted state of the die cross section.

When the guide boss 47 formed on the upper surface of the first die member 43 is brought to confront a hole 3 of the horizontal bar 1, the first die member 43 is arranged to be prevented from longitudinal movement, while the second die member 44 alone is driven in the direction of the arrow in Fig. 36.

In this way, the first die member 43 is moved upwardly as a result of the cooperation between the cam surfaces 45 and 46, so that the guide boss 47 can move into the hole 3.

In this condition, because the lower surface 48 of the first die member 43 contacts the upper surface 49 of the second die member 44, the cross section of the sectional die is at its maximum.

The end portion 30 of the cover 29 is then inserted into an annular groove 50 formed on the upper surface surface of the first die member 43 so as to pass through an annular space between the guide boss 47 and the hole 3, as shown in Figs. 34 and 37. As shown in Fig. 35, the opening end portion 30 of the cover 29 is bent outwardly together with the inner tube 32 and the bar end portion 4a so as to become the inner protrusion of the present invention, when both the vertical bar 4 and the cover 29 are pressed against the first die member 43 so as to allow the engagement of a movable die member 51 with the flanged portion 31. Thereafter, when the second die member 44 is moved in a reverse direction, the sectional die is contracted in cross section, so that the die members 43 and 44 can be drawn out of the horizontal bar 1.

In the case of the embodiment shown in Fig. 39, the flanged portion 31 of the cover 29 is conformed to the shape of the curved outer surface of the vertical bar connecting part 2 of the horizontal bar 1. The cover 29 may be fixed to the bar end portion 4a by an adhesive agent instead of pressing the bar end portion 4a between the cover body 29 and the inner tube 32. As shown in Fig. 41, the inner tube 32 can be omitted. The flanged portion 31 can be also replaced by a plurality of projections 31 a which are disposed discontinuously. Furthermore, the flanged portion 31 can be replaced by a single projection, if it meets strength requirements.

In the case of the embodiments shown in Figs. 25 to 43, there is no fear of damaging the surface of the bar end portion 4a, because it is unnecessary to form a flange portion on the bar end portion 4a by plastic working such as beading. If surface-treatment layers peeled off through the outwardly bending operation, it is unnecessary to treat surfaces again or to repair the surface-treatment layers such as a paint layer after a railing or the like are assembled, because the bar end portion 4a is entirely surrounded by the tubular cover 29.

Therefore, surface-treatment such as painting, and plating can be done on the horizontal and vertical bars before assembling. As there is no fear of having to repair surface-treatment layers and of having to retreat surfaces completely, it is easy to promote production efficiency and to decrease the production cost.

In the case of the modified examples of the present invention shown in Figs. 44 to 47, because the inner protrusion and the outer protrusion are formed simultaneously or successively at a slight time lag, it is unnecessary to perform any operation or working on the vertical bar before the vertical bar is connected to a horizontal bar. Because a circular pipe, a square pipe and the like are used as the vertical bar straight after cutting a given length, it is possible to decrease the assembling labour and cost.

A connecting device used in the modified examples basically comprises a body casing 109 having holes 10 and 111, two core pieces 112 having two protruding parts 11 3 and 114, and an operating rod 11 5 pushing the core pieces 112 outwardly. In the case of the modified example shown in Fig. 44, the connecting device for the upper horizontal bar 101 is separated from that for the lower horizontal bar 105. The body casing 109 is prevented from moving relatively to the vertical bar 102 by a suitable means. When the operating rod 115 is moved in the direction of the arrow by an oil driven hydraulic machine or the like, the core pieces 112 are moved outwardly as a result of the cooperation of a cam surface 116 formed on the operating rod 115 and a cam surface 117 formed on the core member 112.When protruding parts 1 13 and 114 project out of the lateral holes 110 and 111 of the body casing 109, the side wall of the vertical bar 102 is pressed outwardly. In this way, the inner protrusion 118 and the outer protrusion 119 are formed at each side of the vertical bar connecting part 103, 106 of the horizontal bar 101, 105.

The vertical bar connecting part 103 made of a plate is then fitted into opposed grooves of the horizontal bar body 104, as shown in Fig.

45.

In the case of the modified example, shown in Fig. 46, a single body casing 109 passes through the full length of the vertical bar 102.

In the case of the modified example shown in Fig. 47, a single body casing 102 and a single operating rod 115 pass through almost the full length of the vertical bar 102. When the operating rod 115 is moved downwardly by a suitable means such as an oil driven machine, both the upper core members 112 and the lower core members 112 are simultaneously moved outwardly. In all of the above modified examples, a curved leaf spring 123 is interposed between the core member 112 and the body casing 109. When the operating rod 115 is moved back the core members 112 are moved inwardly by the resilience of leaf spring 123, so that the protruding parts 113 and 114 can return into the lateral holes 110 of the body casing 109.

Claims

1. A method for producing a railing or the like which includes at least one horizontal bar and one vertical bar, the method comprising forming a first, outer protrusion on the vertical bar, inserting the vertical bar into a hole formed on a vertical bar connecting part of the horizontal bar, forming a second, inner protrusion on the vertical bar by plastic working such as swelling, rib-forming and bending operations, and gripping or pinching the vertical bar connecting part of the horizontal bar between the inner protrusion and the outer protrusion so as to interconnect the horizontal bar and the vertical bar.

2. A method as claimed in claim 1 in which the outer surface of the vertical bar connecting part is curved, and said outer protrusion is conformed to the shape of the curved outer surface of the vertical bar connecting part.

3. A method as claimed in claim 1 in which the vertical bar is provided with a longitudinal rib on its outer surface, and a portion at each end of the rib is cut off, the outer protrusion being constituted by the remaining portion of the rib, and the inner protrusion being formed on the end portion of the vertical bar from which the rib end portion has been removed.

4. A method as claimed in claim 1 in which a tubular cover is fitted on the end portion of the vertical bar, and the outer protrusion is constituted by a projection formed on the base end of the cover, the end portions of the vertical bar and the cover being bent outwardly so as to form the inner protrusion.

5. A method as claimed in claim 1 in which the inner protrusion of angled section is formed on the side wall of the vertical bar by swelling or nbforming operations.

6. A railing or the like when formed by the method of any of claims 1 to 5.

7. A method substantially as hereinbefore described with reference to Figs. 1 to 7 of the accompanying drawings.

8. A method substantially as hereinbefore described with reference to Figs. 8 to 13 of the accompanying drawings.

9. A method substantially as hereinbefore described with reference to Figs. 14 and 15 of the accompanying drawings.

10. A method substantially as hereinbefore described with reference to Figs. 16 to 18 of the accompanying drawings.

11. A method substantially as hereinbefore described with reference to Figs. 19 to 22 of the accompanying drawings.

12. A method substantially as hereinbefore described with reference to Figs. 23 and 24 of the accompanying drawings.

13. A method substantially as hereinbefore described with reference to Figs. 25 to 28 of the accompanying drawings.

14. A method substantially as hereinbefore described with reference to Figs. 29 to 32 of the accompanying drawings.

15. A method substantially as hereinbefore described with reference to Figs. 33 to 38 of the accompanying drawings.

16. A method substantially as hereinbefore described with reference to Figs. 39 to 43 of the accompanying drawings.

17. A method substantially as hereinbefore described with reference to Figs. 44 to 47 of the accompanying drawings.