AU2014201017A1 - Connectors for structural tubes - Google Patents

Abstract

A frame assembly for a trampoline, the frame assembly including a plurality of frame segments, each frame segment having a tubular member with a spigot portion at one end and a socket portion at the other end whereby the spigot portion of one tubular member is slidably mounted in the socket portion of the adjacent tubular member and so on to form a mat frame, and each frame segment including connecting means at or adjacent the socket portion of each frame member for connecting a leg thereto, the connecting means including a sleeve portion and a leg spigot or socket extending from the sleeve portion, the sleeve portion encapsulating the socket portion of the frame member and being secured thereto by a hollow pin, the hollow pin having a securing portion at one end and a bracing portion at the other end, the securing portion extending through the sleeve portion and the bracing portion being located in the leg spigot or socket and engaging an inner face thereof. 2-7 Leg

Description

1 CONNECTORS FOR STRUCTURAL TUBES This invention relates to connectors for structural tubes. The invention has particular application to lightweight structural tubes and more particularly to connectors for use 5 in the mat frames of playground trampolines. Typically, modern playground trampolines include a frame assembly comprising a circular mat frame which is supported on a plurality of spaced apart legs which rest on the ground. In some cases adjacent legs are connected to each other at their O bottom ends by a foot member. The mat is secured to the circular mat frame by a plurality of circumferentially spaced extension springs which connect to the circular frame at one end via radial slots provided therein and to the mat via hooks at the other end. The circular mat frame is generally 5 constructed of arcuate segments of round tube which are joined together in a spigot and socket arrangement with the end portion of one segment sliding into the end portion of the adjacent segment. In older style trampolines, a similar piece of tube was welded to each arcuate segment so as to depend o perpendicularly therefrom whereby a socket was provided for receiving therein the spigot portion of a complementary leg. However, it was found that the legs tended to flay outwards or bend under the forces applied by a person jumping on the mat, even in cases where adjacent legs were joined by a foot 5 member. The flaying or bending was worse in such cases because the foot member tended to slide across the ground more easily. The problem was believed to be partly due to relative pivoting (or partial rotation) at the spigot and socket joints between adjacent arcuate segments. Unfortunately, when the arcuate O segments partially rotated, the radial slots therein also rotated so that the tension in the springs decreased and the mat sagged to some degree. SVT !.012 Iilrodihrunn2 id 2 The problem was mitigated to some extent by keying the interconnecting arcuate segments so as to substantially prevent relative rotation between the adjacent segments and strengthening the arcuate segments at the region of 5 interconnection. The keying was achieved by drawing the portions of the round tube segments adjacent the opposite ends to form portions of square tube, with the square tube at one end being slightly larger so that the square tubular portion at one end could slidably fit into the square tubular portion ) at the opposite end of the adjacent segment. The square end portions had rounded corners and in some embodiments the square portions were effectively round portions with opposed flat portions. The strengthening was achieved by providing a connector which itself included a square sleeve arranged to 5 tightly slide onto the larger square portion of the arcuate segment so as to encapsulate it thereby effectively forming a laminated wall. The connector was secured to the arcuate segment by a hollow securing pin formed by a short length of round hollow tube which was pressed through aligned holes ) formed in opposite sides of both the connector sleeve and the square end portion and then expanded or swaged at both ends to secure it in position so that it thereby effectively acting as a hollow rivet. The hollow pin then provided a socket for supporting a post upstanding therefrom to which a net could 5 easily be connected. A connector was completed by welding a short piece of round hollow tube to the connector sleeve at right angles to form a depending leg socket adapted to receive the upper end of a leg for supporting the mat frame. The arrangement is described in the present applicant's earlier 0 Australian patent application number 2010246563 which is incorporated herein by way of reference. While the earlier arrangement was generally satisfactory, it is believed that improvements can still be made to achieve cVUL01212filed26February2014 3 a greater load rating with cost effective production especially in respect of the leg socket which could fail under heavy loads. The improvement is achieved by forming the hollow securing pin so that it not only secures the square sleeve to 5 the end portion of the arcuate segment but also strengthens the depending leg socket. In that respect, the present invention provides that the hollow pin is first shaped so that a portion is adapted to be pressed through the opposed spaced apart aligned holes in the larger square end portion and the 1 complementary square sleeve, and an adjacent portion of larger diameter (or larger lateral dimension if not round) engages the inner face of the leg socket thereby supporting the leg socket. While reference has been made to the invention being used 5 with round tubes with square end portions, it will be appreciated that it is not limited to such use and could be used with round tubes with round end portions or square tubes with square end portions or rectangular tubes with rectangular end portions or any suitable combination. Further, the 1 invention could also be used for connecting frame segments of square or rectangular trampolines and thus is not limited to use with arcuate segments. With the foregoing in view, the invention in one aspect resides broadly in a frame assembly for a trampoline, the :5 frame assembly including a plurality of frame segments, each frame segment having a tubular member with a spigot portion at one end and a socket portion at the other end whereby the spigot portion of one tubular member is slidably mounted in the socket portion of the adjacent tubular member and so on to 0 form a mat frame, and each frame segment including connecting means at or adjacent the socket portion of each frame member for connecting a leg thereto, the connecting means including a sleeve portion and a leg spigot or socket extending from the cVULO212filed26Februarv2O4 4 sleeve portion, the sleeve portion encapsulating the socket portion of the frame member and being secured thereto by a hollow pin, the hollow pin having a securing portion at one end and a bracing portion at the other end, the securing 5 portion extending through the sleeve portion and the bracing portion being located in the leg spigot or socket and engaging an inner face thereof. In another aspect, the invention resides broadly in a frame segment for the mat frame of a trampoline, the frame ) segment having a tubular member with a spigot portion at one end and a socket portion at the other end, the spigot portion of one frame segment being adapted to be slidably mounted in the socket portion of a like frame segment and so on to form a mat frame, the frame segment including connecting means at or i adjacent said socket portion for connecting a leg thereto, the connecting means including a sleeve portion and a leg spigot or leg socket extending from the sleeve portion, the sleeve portion encapsulating the socket portion of the frame member and being secured thereto by a hollow pin, the hollow pin ) having a securing portion at one end and a bracing portion at the other end and the securing portion extending through the sleeve portion, and the bracing portion being located in the leg spigot or leg socket and engaging an inner face thereof. Preferably, the spigot portion and the socket portion 5 include complementary keying means adapted to substantially prevent relative pivoting or rotation between adjacent tubular members, Advantageously, it will be appreciated that the bracing portion of the hollow pin supports the leg spigot or socket as o the case may be by engagement with an inner face thereof and the hollow pin itself being supported at two spaced apart locations adds significant stability to the leg spigot or c VULOJ22filed26February2O14 5 socket thereby lessening the stress on the weld between the leg spigot or socket and the sleeve. In yet another aspect, the invention resides broadly in a joint, including: 5 a tubular member; a sleeve encapsulating an end portion of said tubular member; a tubular connector member extending from said sleeve portion and connected thereto; ) a hollow pin securing the sleeve to the tubular member, the hollow pin having a securing portion at one end and a bracing portion at the other end, the securing portion extending through opposed pairs of aligned holes in said sleeve portion and said encapsulated tubular member and 5 engaging an outer face of said sleeve on one side thereof and said bracing portion being located in said tubular connector member and engaging an inner face thereof and an outer face of said sleeve opposite said one side. Preferably, the securing portion of the hollow pin is ) pressed, swaged or rolled to form a flange or the like at its free end which engages the outer face of the sleeve portion. In yet another aspect, the invention resides broadly in a method of forming a joint, including: fitting a sleeve to an end portion of a tubular member so 5 that the sleeve encapsulates said end portion; providing a hollow pin having a securing portion at one end and a bracing portion at the other end, the bracing portion having a greater diameter than said securing portion; pressing said hollow pin through aligned holes in said o sleeve and said tubular member such that said securing portion extends through the aligned holes in said sleeve portion and said encapsulated tubular member and said bracing portion engages an outer face of said sleeve on one side and expanding c VUL01212filed26February2014 6 said hollow pin at its free end such that it engages the outer face of said sleeve on the opposite side so as to secure said sleeve and said tubular member together. Preferably, the method includes connecting a tubular 5 connector member to said sleeve before or after fitting said sleeve to said tubular member so as to extend laterally therefrom and pressing said hollow pin through said tubular connector member such that the outer face of the bracing portion engages the inner face of said tubular connector 3 member. In still yet another aspect, the invention resides broadly in a T-piece for use in constructing the mat frame of a trampoline, the T-piece including: a tubular member having two substantially coaxial opposed 5 end portions forming sockets, each socket being adapted to slidably receive therein an end portion of a tubular frame segment and each socket including keying means adapted to engage with complementary keying means on an end portion of the tubular segment so as to prevent relative pivoting or D rotation therebetween; a sleeve extending about said tubular member and being secured thereto against relative movement therebetween by a hollow lightweight pin and a hollow spigot or socket portion extending from said sleeve for connecting a leg thereto; .5 said hollow lightweight pin having a securing portion at one end and a bracing portion at the other end, the securing portion extending through opposed aligned holes in said sleeve and said tubular member and engaging an outer face of said sleeve on one side thereof at its free end and said bracing 30 portion being located in the leg spigot or leg socket and engaging an outer face of said sleeve opposite said one side and an inner face of said hollow spigot or socket. rVUTLO,1212filed26Februarv2O14 7 In yet another aspect, the invention resides broadly in a leg mounting system for a trampoline, including: a plurality of frame segments, each frame segment having a tubular member with a spigot portion at one end and a socket 5 portion at the other end, the spigot portion of one frame segment being adapted to be slidably mounted in the socket portion of a like frame segment and so on to form a mat frame, the frame segment including connecting means at or adjacent said socket portion for connecting a leg thereto, the ) connecting means including a sleeve portion and a leg spigot or leg socket extending from the sleeve portion, the sleeve portion encapsulating the socket portion of the frame member and being secured thereto by a hollow pin, the hollow pin having a securing portion at one end and a bracing portion at 5 the other end and the securing portion extending through the sleeve portion, and the bracing portion being located in the leg spigot or leg socket and engaging an inner face thereof. Preferably, the spigot portion and the socket portion include complementary keying means adapted to prevent relative 3 pivoting or rotation between adjacent connected tubular members. In a preferred form, the spigot portion and the socket portion are of square or rectangular cross section with the spigot being adapted to tightly fit within the socket. In such form, the square or rectangular section is preferably 5 obtained by drawing the end portion of a round hollow tube to at least form opposed pairs of flat sides joined by rounded corners. However, other keying shapes may be formed if desired. In still yet another aspect, the invention resides 0 broadly in a trampoline incorporating any one or more of the components previously described. Preferably, the hollow pin is secured as previously described. Suitably, such arrangement cVUL01212filed26Februarv2014 8 provides a stable support for the upstanding post in line with the leg. In order that the invention may be more easily understood and put into practical effect, reference will now be made to 5 the accompanying drawings wherein: Fig. 1 is a schematic pictorial representation of a trampoline according to the present invention;. Fig. 2 is a detail pictorial representation of part of the mat frame of the trampoline of Fig. 1 shown at "2" in Fig. Q 1; Fig. 3a is a top plan of one arcuate segment of the mat frame of the trampoline of Fig. 1; Fig. 3b is a sectional end elevation of the arcuate segment shown in Fig. 3a along line 3b-3b; 5 Fig. 4 is a side elevation of one end portion of the arcuate segment shown in Fig. 3a with a portion of the trampoline leg fitted thereto; Fig. 5 is an end view of the one end portion of the arcuate segment shown in Fig. 3a with a portion of the D trampoline leg fitted thereto; Fig. 6 is a plan of the one end portion of the arcuate segment shown in Fig. 3a with a portion of the trampoline leg fitted thereto; Fig. 7 is a sectional side elevation of the one end !5 portion of the arcuate segment of Fig. 3a along line 7-7 with a portion of the trampoline leg fitted thereto; Fig. 8 is a blown up view of part of the arcuate segment shown in section in Fig. 7 with a portion of the trampoline leg fitted thereto; 30 Fig. 9 is a pictorial representation of the end portion shown in Fig. 4 with a portion of the trampoline leg fitted thereto; cVULO2l2filed26February2OJ4 9 Fig. 10 is a pictorial representation of the end portion shown in Fig. 4 with a portion of the trampoline leg fitted there with the components in line for assembly; Fig. 11 is a sectional side elevation of the one end 5 portion of the arcuate segment shown in Fig. 3a also along line 7-7 with a safety net support post mounted thereto; Fig. 12 is a sectional end elevation of the one end portion of the arcuate segment shown in Fig. 3a with the safety net support post mounted thereto; and ) Fig. 13 is a side elevation of the one end portion of the arcuate segment shown in Fig. 3a with the safety net support post mounted thereto. The trampoline 10 illustrated in Fig. 1 includes a circular mat frame 11 which is supported on a plurality of 5 spaced apart legs 12 arranged in pairs with the two legs of each pair being connected at their lower ends by a cross member 13. A trampoline mat 14 is suspended within the circular frame member 11 by a plurality of circumferentially spaced extension coil springs 16 which extend between the ) periphery 17 of the mat and the mat frame and are connected at their inner ends 18 to the mat frame as will be described in more detail later and at their outer ends 19 to the mat frame. The extension springs are covered by an annular ring of padding 21 which is secured to the mat frame via the springs 5 as also will be described in more detail later. A plurality of circumferentially spaced posts 23 stand up from the mat frame to provide support for a safety net 24 which extends about the periphery of the mat 14 as shown in Fig. 1 with the portion between the two front posts removed o for clarity, that portion having therein a closable opening for gaining access to the mat. The safety net is secured to each of the posts 23 by a top strap 26 and a centre strap 27. c VUL01212filed26February2014 10 The circular mat frame 11 comprises eight arcuate segments lla one of which is more clearly shown in Fig. 3. The number of arcuate segments used to form the mat frame will depend on the diameter of the trampoline concerned. 5 Each arcuate segment includes an elongate arcuate thin walled round tube portion 30 having an arcuate longitudinal axis 31 with a short necked portion 32 at one end and a longer necked portion 33 at the other end. The two necked portions are formed so as to be generally square in cross-section, that 3 is, to be thin walled square hollow cross section tubular portions, although as can be seen in Figs. 5 and 10, they have large radiused corners 35 and effectively are round tubes with flat side portions 36. However, sharper corners can be obtained in different drawing operations depending on the wall 5 thickness and other factors. They are also formed such that the width of the short necked portion is slightly smaller than that of the long necked portion such that it can form a tight sliding fit in the long necked portion of an adjacent segment. Advantageously, the flat sides provide a form of keying to 0 prevent relative rotation between adjacent segments. However, in other forms of the invention, other types of keying can be used, for example, pressing a recess in the spigot and a complementary protuberance in the socket wall. Suitably, each arcuate portion includes a plurality of !5 spaced apart slots 36 formed therein as can be more clearly seen in Fig. 3b for connection of the extension springs 16 thereto. A "T" or "L" piece 40 is secured to the tubular portion 30 at the long necked end, the "L" piece having a top 30 connector portion 42 also formed of hollow square section thin walled tube which is of slightly greater width than the long necked end portion 33 such that it can be pressed thereon to form a tight fit, and a spigot portion 43 depending therefrom cVULO212fiIed26February2O4 11 with a longitudinal (or vertical) axis 44 for connecting one of the legs 12 thereto. The long necked portion is secured in the top portion by a large hollow pin 46 (which acts in a manner similar to a 5 rivet) which is coaxial with the spigot portion 43 and suitably pressed to clamp the top portion and the long necked portion of the arcuate segment together so as to prevent relative longitudinal movement and relative rotational movement therebetween. In this respect, the hollow pin 46 is 0 formed by drawing a piece of round hollow steel tube so as to form a cylindrical securing portion 51 of smaller diameter and a cylindrical bracing portion 52 of larger diameter which are joined by a transition portion of substantially conical shape. To construct the T or L piece 40, a pair of spaced apart 5 aligned holes 56 are drilled through the opposite sides of long spigot 33 and corresponding holes 57 are drilled through the opposite sides of the sleeve 42. The socket 43 is then welded to the sleeve coaxial with the holes 57 as shown at 54. The sleeve is then pushed onto the long spigot with holes 56 0 and 57 aligned. Then hollow pin 46 is fitted by pushing it through socket 43 such that the securing portion passes through the sleeve 42 and the encapsulated spigot end until the conical transition portion suitably engages the outer face of the sleeve on its bottom wall and a portion is exposed Z5 above the outer face of the top wall whereupon the free end 58 of the hollow pin is pressed to force it to roll outwards to form a "flange" which acts in conjunction with the conical transition to hold the sleeve and the long spigot together. As can be seen in Fig. 8, the outer face of the bracing 30 portion 52 of the hollow pin 46 engages the inner face of the socket 43 thereby providing rigid support and decreasing stress on welds 54. Additionally, the free end 59 of the c VUL01212filed26Februarv2014 12 bracing portion of the hollow pin also forms a stopper for the legs 12 as shown at 61. It will be appreciated that when the short necked end portion of one arcuate segment is engaged in the long necked 5 portion of an adjacent segment, that long necked portion is also tightly engaged in the square T portion thus being secured within a two layers of square tube with both layers acting to inhibit distortion of the long necked portion therewithin. The limitation or prevention of distortion 3 advantageously prevents relative rotation of one arcuate segment with the adjacent one and thereby restricts or prevents flaying in or out of the legs 12 which can be caused by the forces applied to the circular frame when a person jumps on the trampoline mat. 5 Advantageously, the hollow pin 46 provides a socket 47 in which the posts 23 are mounted by virtue of a complementary mounting pin or spigot secured in their lower end portions. The posts can be secured in the socket by fitting a pin in a lateral bore passing through the sleeve 42, the spigot 33 and 3 the hollow pin 46 perpendicular to its longitudinal axis as described in the earlier application. In use, the square tube connection between adjacent arcuate segments lla inhibits relative rotation or pivoting therebetween and consequently the legs 12 are also inhibited !5 from flaying inwards or outwards and consequently the mat frame 11 as a whole remains generally level (or planar) and the spring slots 36 retain their correct direction of opening directly towards the centre of the mat thereby keeping the springs properly aligned and tensioned. Advantageously, the 0 present invention strengthens the connection between the leg socket 43 and the sleeve 42 and reduces the chance of failure at that point. cVUL01212fled26February2014

Claims (10)

1. A frame assembly for a trampoline, the frame assembly including a plurality of frame segments, each frame segment having a tubular member with a spigot portion at one end and a 5 socket portion at the other end whereby the spigot portion of one tubular member is slidably mounted in the socket portion of the adjacent tubular member and so on to form a mat frame, and each frame segment including connecting means at or adjacent the socket portion of each frame member for D connecting a leg thereto, the connecting means including a sleeve portion and a leg spigot or socket extending from the sleeve portion, the sleeve portion encapsulating the socket portion of the frame member and being secured thereto by a hollow pin, the hollow pin having a securing portion at one 5 end and a bracing portion at the other end, the securing portion extending through the sleeve portion and the bracing portion being located in the leg spigot or socket and engaging an inner face thereof. 0

2. A frame segment for the mat frame of a trampoline, the frame segment having a tubular member with a spigot portion at one end and a socket portion at the other end, the spigot portion of one frame segment being adapted to be slidably mounted in the socket portion of a like frame segment and so 5 on to form a mat frame, the frame segment including connecting means at or adjacent said socket portion for connecting a leg thereto, the connecting means including a sleeve portion and a leg spigot or leg socket extending from the sleeve portion, the sleeve portion encapsulating the socket portion of the 30 frame member and being secured thereto by a hollow pin, the hollow pin having a securing portion at one end and a bracing portion at the other end and the securing portion extending through the sleeve portion, and the bracing portion being cVUL01212filed26Februarv2014 14 located in the leg spigot or leg socket and engaging an inner face thereof.

3. A joint, including: a tubular member; a sleeve encapsulating an end portion of said tubular member; a tubular connector member extending from said sleeve portion and connected thereto; ) a hollow pin securing the sleeve to the tubular member, the hollow pin having a securing portion at one end and a bracing portion at the other end, the securing portion extending through opposed pairs of aligned holes in said sleeve portion and said encapsulated tubular member and 5 engaging an outer face of said sleeve on one side thereof and said bracing portion being located in said tubular connector member and engaging an inner face thereof and an outer face of said sleeve opposite said one side.

) 4. A T-piece for use in constructing the mat frame of a trampoline, the T-piece including: a tubular member having two substantially coaxial opposed end portions forming sockets, each socket being adapted to slidably receive therein an end portion of a tubular frame 5 segment and each socket including keying means adapted to engage with complementary keying means on an end portion of the tubular segment so as to prevent relative pivoting or rotation therebetween; a sleeve extending about said tubular member and being 0 secured thereto against relative movement therebetween by a hollow lightweight pin and a hollow spigot or socket portion extending from said sleeve for connecting a leg thereto; cVUL012J2filed26February2014 15 said hollow lightweight pin having a securing portion at one end and a bracing portion at the other end, the securing portion extending through opposed aligned holes in said sleeve and said tubular member and engaging an outer face of said 5 sleeve on one side thereof at its free end and said bracing portion being located in the leg spigot or leg socket and engaging an outer face of said sleeve opposite said one side and an inner face of said hollow spigot or socket.

) 5. A leg mounting system for a trampoline, including: a plurality of frame segments, each frame segment having a tubular member with a spigot portion at one end and a socket portion at the other end, the spigot portion of one frame segment being adapted to be slidably mounted in the socket 5 portion of a like frame segment and so on to form a mat frame, the frame segment including connecting means at or adjacent said socket portion for connecting a leg thereto, the connecting means including a sleeve portion and a leg spigot or leg socket extending from the sleeve portion, the sleeve ) portion encapsulating the socket portion of the frame member and being secured thereto by a hollow pin, the hollow pin having a securing portion at one end and a bracing portion at the other end and the securing portion extending through the sleeve portion, and the bracing portion being located in the 5 leg spigot or leg socket and engaging an inner face thereof.

6. A frame assembly, a frame segment, a leg mounting system or a joint according to any one of the preceding claims wherein the securing portion of the hollow pin is pressed, 0 swaged or rolled to form a flange or the like at its free end and said flange engages the outer face of the sleeve portion. c VUL01212filed26February2014 16

7. A frame assembly, a frame segment, a leg mounting system or a joint according to any one of the preceding claims wherein the spigot portion and the socket portion include complementary keying means adapted to prevent relative 5 pivoting or rotation between adjacent connected tubular members.

8. A trampoline incorporating a frame assembly, a frame segment, a leg mounting system, or a joint according to any O one of the preceding claims.

9. A method of forming a joint, including: fitting a sleeve to an end portion of a tubular member so that the sleeve encapsulates said end portion; 5 providing a hollow pin having a securing portion at one end and a bracing portion at the other end, the bracing portion having a greater diameter than said securing portion; pressing said hollow pin through aligned holes in said sleeve and said tubular member such that said securing portion 0 extends through the aligned holes in said sleeve portion and said encapsulated tubular member and said bracing portion engages an outer face of said sleeve on one side and expanding said hollow pin at its free end such that it engages the outer face of said sleeve on the opposite side so as to secure said 25 sleeve and said tubular member together.

10. A method according to Claim 9 including connecting a tubular connector member to said sleeve before or after fitting said sleeve to said tubular member so as to extend 30 laterally therefrom and pressing said hollow pin through said tubular connector member such that the outer face of the bracing portion engages the inner face of said tubular connector member. cVUL01212flled26February2014