Expansion Joint for Construction Cable Trays

Abstract

The present invention relates to an expansion joint for a cable tray for construction, comprising: a variable rail (20) whose spacing between each other changes due to thermal expansion and contraction caused by temperature changes; a pair of pivot pins (30) each installed on the outer side of the variable rail (20); a rotation center end (41) supported by the pivot pin (30), and a pivot end (42) that extends toward each other by the same length and overlaps in a V-shape to pivotally connect, and two pairs of V-links (40) positioned parallel to each other with a constant vertical spacing; and a connecting rod (43) that pivotally connects both ends to the pivot end (42) so as to cross vertically between the pivot ends (42) to form a symmetrical parallelogram link together with the V-links (40).

Description

Technology Field

[0001] The present invention relates to an expansion joint for a cable tray for construction, and more specifically, to an expansion joint for a cable tray for construction that prevents deformation of the cable tray by allowing it to move in opposite longitudinal directions when the cable tray for laying electrical cables contracts or expands due to temperature changes. Background Technology

[0002] Generally, large-capacity electrical cables installed in buildings are laid using cable trays. When the temperature around the cable tray changes, the side rails constituting the cable tray contract or expand along their length.

[0003] As the length of the cable tray increases, the amount of shrinkage or expansion accumulates, causing the cable tray to deform more significantly. This leads to permanent deformation of the cable tray and causes damage to the installed electrical cables. Prior art literature

[0004] Korean Registered Patent No. 10-2393159 (Published May 2, 2022) Korean Registered Patent No. 10-2099289 (Published April 8, 2020) Korean Registered Patent No. 10-1831953 (Published April 4, 2018) The problem to be solved

[0005] The present invention was made to solve the above-mentioned problems, and its purpose is to provide an expansion joint for a construction cable tray that can prevent permanent deformation of the cable tray due to temperature changes. means of solving the problem

[0006] An expansion joint for a cable tray for construction, for achieving the purpose of the present invention, comprises: a variable rail whose spacing between them changes due to thermal expansion and contraction caused by temperature changes; a pair of pivot pins installed on the outer sides of the variable rails; two pairs of V-links positioned parallel to each other with a constant vertical spacing, wherein the pivot center end is supported by the pivot pin, the pivot ends extend toward each other by the same length to overlap in a V-shape and pivotally connected, and the pivot ends overlap the pivot ends to form a V-shape and pivotally connected, and the connecting rods that cross vertically between the pivot ends and pivotally connected to form a symmetrical parallelogram link together with the V-links.

[0007] The present invention comprises: two pairs of compression sections parallel to the variable rail, formed by rolling a portion of the upper and lower ends of the variable rail into a cylindrical shape; a pair of parallel guide bushes installed at the center of the compression section formed on one variable rail; a pair of parallel fixing bars installed at the center of the compression section formed on the other variable rail; and a pair of parallel slide shafts extending in a straight line from one end of the fixing bar toward the guide bushes and loosely inserted into the center of the guide bushes.

[0008] The present invention comprises: a bushing groove formed annularly along the outer circumference of a guide bushing; a bar groove formed annularly along the outer circumference of a fixing bar; and an axial locking piece formed by partially cutting and inwardly deforming a portion of a compression part, which enters and engages with the bushing groove and the bar groove.

[0009] The present invention comprises: a spring catch formed at the end of a pivot pin; a tension spring installed by hooking both ends to the spring catch to traverse diagonally between variable rails, and transmitting a contraction force due to elastic restoring force to the spring catch to apply a unidirectional preload so that adjacent variable rails come closer to each other; and an anti-detachment groove formed annularly along the outer circumference of the spring catch to hook hooks formed at both ends of the tension spring. Effects of the invention

[0010] As described above, the present invention is configured to absorb the amount of change by connecting the variable rails (20) located on both sides by means of a V-link (40) and a connecting rod (43) when the variable rail (20) contracts or expands in the longitudinal direction due to a change in the temperature around the cable tray, thereby having the effect of preventing permanent deformation of the variable rail (20).

[0011] When the variable rail (20) contracts or expands in the longitudinal direction due to a change in the temperature around the cable tray, the variable rails (20) located on both sides are configured to absorb the amount of change by guiding them in a straight line by the guide bush (50) and the slide shaft (62), thus having the effect of preventing permanent deformation of the variable rail (20).

[0012] Since the pivoting end (42) of the upper and lower V-links (40) is connected by a connecting rod (43), it has the effect of inducing the rotation of both the upper and lower V-links (40) at the same angle.

[0013] Since the V-link (40) and connecting rod (43) connected in the form of a parallelogram link are installed to form left-right symmetry, the movement of both variable rails (20) can be constrained in a mutually symmetrical pattern.

[0014] Since the guide bush (50) and the fixing bar (60) are configured to be installed by pressing them into the center of the compression part (21) formed on the variable rail (20), the guide bush (50) and the fixing bar (60) can be firmly fixed to the compression part (21).

[0015] Since an axial catch piece (22) that engages with the bush catch groove (51) formed in the guide bush (50) and the bar catch groove (61) formed in the fixing bar (60) is formed in the compression part (21), there is an effect of preventing the guide bush (50) and the fixing bar (60) from detaching from the compression part (21) when an excessive force is applied in the axial direction of the guide bush (50) and the fixing bar (60).

[0016] Since the elastic restoring force generated from the tension spring (70) is transmitted to the pivot pin (30) installed on both variable rails (20) through the spring catch (31) to apply preload to both variable rails (20) in a direction that brings them closer to each other, the effect of preventing the two variable rails (20) from spreading too far apart can also be expected. Brief explanation of the drawing

[0017] FIG. 1 is an exploded perspective view showing a guide bush, a slide shaft, a compression part, and surrounding components for linearly guiding a variable rail according to the present invention. FIG. 2 is an exploded perspective view showing a configuration for guiding a variable rail in the form of a parallelogram link by means of a V-link and a connecting rod according to the present invention. FIG. 3 is an enlarged perspective view of the essential part of the present invention. FIG. 4 is a perspective view of FIG. 3 seen from the opposite side. FIG. 5 is a perspective view showing the variable rail according to the present invention moved in a direction in which the gap narrows. FIG. 6 is a perspective view showing the variable rail according to the present invention moved in a direction in which the gap widens. FIG. 7 is a front view showing an electric cable laid in a cable tray according to the present invention. FIG. 8 is a side view showing an enlarged portion of FIG. 5. FIG. 9 is an enlarged side view of the main part of FIG. 6. FIG. 10 is an enlarged cross-sectional view along line A-A' of FIG. 8 FIG. 11 is an enlarged cross-sectional view along line B-B' of FIG. 10. Specific details for implementing the invention

[0018] Embodiments according to the present invention will be described in detail below with reference to the attached drawings, FIGS. 1 to 11.

[0019] The present invention includes a variable rail (20) whose spacing between each other changes due to thermal expansion and thermal contraction caused by temperature changes; and pivot pins (30) installed in pairs on the outer sides of the variable rail (20).

[0020] The variable rail (20) can be formed using a steel plate of a constant thickness and a roller forming method so that the cross-sectional shape is continuous in the longitudinal direction. The pivot pin (30) can be formed using a metal round bar and by turning or cold forging.

[0021] As shown in FIGS. 5 to 7, the left and right variable rails (20) are connected by a rung (24) that crosses between the left and right variable rails (20). As shown in FIG. 7, an electric cable (25) is laid over the rung (24).

[0022] As shown in FIG. 10, if a flat disc-shaped head portion (not shown) that is attached to the rotation center end (41) of the V-link (40) is formed on the pivot pin (30), the rotation center end (41) can be prevented from detaching. After passing the tip of the pivot pin (30) through the center of the rotation center end (41) and inserting it into the pin hole (23) drilled in the variable rail (20), the tip of the pivot pin (30) protruding to the opposite side can be flattened into a rivet head shape using a forming tool such as a punch or a hammer, thereby preventing the pivot pin (30) from detaching from the variable rail (20).

[0023] The rotation center end (41) according to the present invention is supported by a pivot pin (30), and the pivot end (42) extends toward each other by the same length and overlaps in a V-shape to pivotally connect, and includes two pairs of V-links (40) positioned parallel to each other with a constant vertical spacing.

[0024] The V-link (40) can be formed into a flat, long bar shape using a steel plate of a certain thickness. Both pairs of V-links (40) can be formed with the same length and shape.

[0025] A through hole through which a pivot pin (30) passes is drilled in the center of the rotation center end (41) formed in the V-link (40), and a pin hole (23) for inserting the pivot pin (30) is drilled on the side of the variable rail (20).

[0026] As shown in FIG. 2, if a ring-shaped spacer (44) is installed between the rotation center end (41) of the V-link (40) and the outer surface of the variable rail (20), the V-link (40) can avoid contact with the surface of the variable rail (20) when the V-link (40) rotates.

[0027] A through hole through which a connecting pin (45) passes is also drilled in the center of the pivot section (42) formed in the V-link (40). If the tip of the connecting pin (45), which passes through the center of the pivot section (42) and protrudes to the opposite side, is flattened into a rivet head shape using a forming tool such as a punch or a hammer, the pivot section (42) can be prevented from detaching.

[0028] The rotation center end (41) of the V-link (40) and the pivot pin (30) can be loosely connected so that the V-link (40) rotates freely around the pivot pin (30).

[0029] The present invention includes a connecting rod (43) that forms a symmetrical parallelogram link together with a V-link (40) by pivotally connecting both ends to the pivoting section (42) so as to cross vertically between the pivoting sections (42).

[0030] The upper and lower ends of the connecting rod (43) are overlapped and joined to the pivoting end (42) formed in the V-link (40). After overlapping the upper and lower ends of the connecting rod (43) to the pivoting end (42) of the V-link (40), a connecting pin (45) is inserted through the holes drilled in the upper and lower ends of the connecting rod (43) and the holes drilled in the pivoting end (42) to loosely join them, thereby allowing the V-link (40) and the connecting rod (43) to rotate freely.

[0031] A disc-shaped flat rivet head can be formed at the rear end of the connecting pin (45). After passing the front end of the connecting pin (45) through a hole formed at the center of the upper and lower ends of the connecting rod (43) and the pivot end (42), the front end of the connecting pin (45) protruding to the opposite side is flattened into a rivet head shape using a forming tool such as a punch or a hammer, thereby preventing the V-link (40), connecting rod (43), and connecting pin (45) from coming apart.

[0032] The present invention comprises two pairs of compression parts (21) parallel to the variable rail (20) formed by rolling up a portion of the upper and lower ends of the variable rail (20) into a cylindrical shape; and one pair of parallel guide bushes (50) installed at the center of the compression part (21) formed on one variable rail (20).

[0033] As illustrated in FIGS. 1 and FIGS. 10, the compression portion (21) can be formed in a shape that curls inward toward the inside of the variable rail (20) from the upper and lower ends of the variable rail (20). The compression portions (21) located at the upper and lower ends of the variable rail (20) can be formed to curl in a direction facing each other.

[0034] The inner diameter of the compression part (21) corresponds to the outer diameter of the guide bush (50). After inserting the guide bush (50) into the center of the compression part (21), the surface of the compression part (21) is deformed by applying pressure toward the center of the guide bush (50), and the guide bush (50) is compressed against the inner circumference of the compression part (21).

[0035] The guide bush (50) can be formed using a powder sintered alloy impregnated with oil. A straight hole is drilled in the center of the guide bush (50) to guide the slide shaft (62). The guide bush (50) and the slide shaft (62) are loosely connected to each other so that the slide shaft (62) moves freely at the center of the guide bush (50).

[0036] The present invention includes a pair of parallel fixed bars (60) installed at the center of a compression portion (21) formed on the other variable rail (20); and a pair of parallel slide shafts (62) that extend in a straight line from one end of the fixed bar (60) toward the guide bush (50) and are loosely inserted into the center of the guide bush (50).

[0037] As illustrated in FIGS. 1 and FIGS. 10, the inner diameter of the compression part (21) corresponds to the outer diameter of the fixing bar (60). When the fixing bar (60) is inserted into the center of the compression part (21) and then the surface of the compression part (21) is deformed by pressing it toward the center of the fixing bar (60), the fixing bar (60) is compressed against the inner circumference of the compression part (21).

[0038] The fixed bar (60) and the slide shaft (62) can be integrally formed using a metal round bar as the material. The slide shaft (62) can be formed into a diagonal bar shape having a diameter smaller than the diameter of the fixed bar (60).

[0039] The present invention includes a bush catch groove (51) formed in an annular shape along the outer circumference of a guide bush (50); a bar catch groove (61) formed in an annular shape along the outer circumference of a fixing bar (60); and an axial catch piece (22) formed by partially cutting and deforming inward a portion of a compression part (21) and entering and catching in the bush catch groove (51) and the bar catch groove (61).

[0040] As shown in FIGS. 1 and 10, when a portion of the compression part (21) is cut to a width that matches the width of the bush catch groove (51) and the bar catch groove (61), and then the cut portion is pressed toward the bush catch groove (51) and the bar catch groove (61) to indent or bend, the deformed axial catch piece (22) enters and catches into the bush catch groove (51) and the bar catch groove (61), respectively.

[0041] Such axial locking pieces (22) prevent the guide bush (50) and the fixing bar (60) from axially detaching from the compression part (21).

[0042] The present invention includes a spring catch (31) formed at the end of a pivot pin (30); a tension spring (70) installed by hooking both ends to the spring catch (31) to traverse diagonally between variable rails (20), and applying a unidirectional preload to the adjacent variable rails (20) by transmitting a contraction force due to elastic restoring force to the spring catch (31); and an anti-detachment groove (32) formed in an annular shape along the outer circumference of the spring catch (31) to hook (71) formed at both ends of the tension spring (70).

[0043] The spring catch portion (31) can be formed to extend longitudinally from the center of the head portion formed on the pivot pin (30). The tension spring (70) can be composed of a tension coil spring made by winding a spring steel wire spirally. The hooks (71) formed at both ends of the tension spring (70) can be formed in a U-shape.

[0044] The anti-detachment groove (32) formed on the outer surface of the spring catch (31) is formed to have a certain depth and width. In particular, if the width of the anti-detachment groove (32) is formed to be slightly larger than the diameter of the hook (71), it is easy to hook the hook (71) into the anti-detachment groove (32).

[0045] The operation according to the present invention will be described in detail below with reference to the attached drawings.

[0046] When the temperature around the cable tray rises, the length of the variable rail (20) is extended due to thermal expansion, and when the temperature falls, the length of the variable rail (20) is contracted due to thermal contraction. As shown in FIG. 8, when the length of the variable rail (20) is extended due to thermal expansion, both variable rails (20) move in a direction that narrows the gap between the variable rails (20), and at this time, the V-link (40) rotates around the pivot pin (30), and the pivot end (42) of the V-link (40) descends.

[0047] The V-links (40) located at the upper and lower ends are all rotated at the same angle by the connecting rod (43) connected to the pivot end (42) of the V-link (40). The V-links (40) arranged symmetrically in the left and right directions in the drawing of FIG. 8 with respect to the connecting rod (43) move together with the connecting rod (43) in the form of a parallelogram link, and the movement of both variable rails (20) is constrained in the same pattern by the V-link (40) and the connecting rod (43).

[0048] As illustrated in FIGS. 1, 10, and 11, when the variable rail (20) is linearly guided by the guide bush (50) and the slide shaft (62), when the distance between the variable rails (20) narrows or widens, the slide shaft (62) slides along the hole formed in the guide bush (50) to linearly guide the variable rail (20) in the longitudinal direction. Since the guide bush (50) and the slide shaft (62) are configured as a parallel pair, it is possible to prevent the variable rail (20) from rotating around the slide shaft (62).

[0049] In particular, when the variable rail (20) moves in a direction where the gap between them narrows due to the preload applied by the tension spring (70) installed by hooking onto the spring catch (31) formed on the pivot pin (30), the elastic restoring force acting from the tension spring (70) is increased to help the variable rail (20) move.

[0050] When the variable rail (20) moves in a direction that causes the gap between the variable rails (20) to widen, the elastic restoring force of the tension spring (70) acts as a resisting force to prevent the gap between the variable rails (20) from widening excessively. Explanation of the symbols

[0051] 20 : Variable rail 21 : Compression part 22 : Axial locking piece 30 : Pivot pin 31: Spring catch 32: Anti-detachment groove 40 : V-link 41 : Rotation center section 42: Slewing section 43: Connecting rod 50 : Guide bush 51 : Bush catch groove 60 : Fixed bar 61 : Bar catch groove 62 : Slide shaft 70 : Tension spring 71 : Hook

Claims

Claim 1 An expansion joint for a cable tray for construction, characterized by comprising: a variable rail (20) whose spacing between each other changes due to thermal expansion and contraction caused by temperature change; a pair of pivot pins (30) each installed on the outer side of the variable rail (20); two pairs of V-links (40) positioned parallel to each other with a constant vertical spacing, wherein the rotation center end (41) is supported by the pivot pin (30), the pivot end (42) extends toward each other by the same length and overlaps in a V-shape to pivotally connect, and the two pairs of V-links (40) are positioned parallel to each other with a constant vertical spacing; and a connecting rod (43) whose ends overlap and pivotally connect to the pivot end (42) so as to cross vertically between the pivot end (42) to form a symmetrical parallelogram link together with the V-link (40). Claim 2 An expansion joint for a cable tray for construction, characterized in that, in claim 1, the upper and lower portions of the variable rail (20) are formed by rolling them into a cylindrical shape and there are two pairs of compression portions (21) parallel to the variable rail (20); a pair of parallel guide bushes (50) installed at the center of the compression portions (21) formed on one variable rail (20); a pair of parallel fixing bars (60) installed at the center of the compression portions (21) formed on the other variable rail (20); and a pair of parallel slide shafts (62) that extend in a straight line from one end of the fixing bar (60) toward the guide bushes (50) and are loosely inserted into the center of the guide bushes (50). Claim 3 An expansion joint for a cable tray for construction, characterized in that, in paragraph 2, it comprises: a bush catch groove (51) formed in an annular shape along the outer circumference of the guide bush (50); a bar catch groove (61) formed in an annular shape along the outer circumference of the fixing bar (60); and an axial catch piece (22) formed by partially cutting and deforming a part of the compression part (21) inward, and which enters and catches the bush catch groove (51) and the bar catch groove (61). Claim 4 An expansion joint for a cable tray for construction, characterized in that, in any one of claims 1 to 3, it comprises: a spring catch portion (31) formed at the end of the pivot pin (30); a tension spring (70) installed by hooking both ends to the spring catch portion (31) to traverse diagonally between the variable rails (20), and transmitting a contraction force due to elastic restoring force to the spring catch portion (31) to apply a preload in one direction so that adjacent variable rails (20) come closer to each other; and an anti-detachment groove (32) formed in an annular shape along the outer circumference of the spring catch portion (31) to hook and install hooks (71) formed at both ends of the tension spring (70).

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