STRETCHING METHOD AND APPARATUS

Abstract: A carpet stretching assembly is disclosed which includes a ladder-type mounting structure (51, 61) engaged by releasable stretching means (11). The stretching means (11) are actuated by a hydraulic ram (76) or ratchet jack (15, 16) to engage the mounting structure (51) and thereby apply force to stretch a carpet via a gripping head assembly (12) which engages the carpet. The stretched carpet is held in its stretched condition by positioning carpet holding means (111) to engage the mounting structure (61) and grip the carpet by a gripping head assembly (113).

Description: "STRETCHING METHOD AND APPARATUS" BACKGROUND OF THE INVENTION This invention relates to apparatus for stretching o tensioning sheet-like material such as carpet and to method of stretching or tensioning such material. This invention has particular but not exclusive use to th stretching of carpets, and for illustrative purpose reference will be made to such application. However it wil be understood that this invention could be used in othe applications where the stretching or tensioning of sheet like material is required and references herein to "carpet are to be construed as including reference to other sheet like material. DESCRIPTION OF THE PRIOR ART Known carpet stretching equipment includes an extendabl pole or support rod to which is attached a carpet grippin head or stopper. One end of the support rod is positione against a wall of the area to be carpeted with the othe remote end carrying the gripping head or stopper which grip the carpet with a large number of downwardly projectin spikes. The carpet is stretched by the application of forc or pressure to the gripping head so as to cause the grippin SUBSTITUTESHEET head to move relative to the supporting pole. Thi arrangement is used for domestic installations as well a for large scale commercial installations. In practice th length of carpet runs which may be efficiently stretched b this method is limited to lengths of about twenty metres. Thus, where an extended length of carpet such as sixty or eighty metres is to be laid in commercial or industrial applications, the carpet must be stretched to this shorter distance and then tacked down or stay-nailed intermediate its length. The stretching equipment is then repositioned or extended and the stretching operation recommenced. It is also necessary with existing arrangements for the stretching operation to be carried out repeatedly across the width of a carpet. This adds considerably to the time and effort required to lay the carpet. Another disadvantage associated with the existing stretchers occurs when separate lengths of carpets are joined by applying a heat activated thermoplastic adhesive tape to adjoining seams of, the carpet. Because the adhesive tape is not meant to be stretched, it is important that the lengths of carpet to be joined are equally stretched before application of the tape. As the requisite equal stretching is very difficult to achieve, joints often fail by cupping and breaking of the adhesive bond. The current methods are time consuming and do not enabl carpet to be stretched uniformly across its length an width. Consequently it is difficult with existing equipmen to meet required standards when laying carpet, althoug experienced and skillful layers are able to approximate th standards required. Nevertheless it is not uncommon fo bubbling and premature wearing to occur. This invention aims to alleviate the abovementione disadvantages and to provide stretching apparatus which wil be reliable and efficient in use. Other objects an advantages of this invention will hereinafter becom apparent. DESCRIPTION OF THE PRESENT INVENTION With the foregoing and other objects in view, this inventio in one aspect resides broadly in a carpet stretchin assembly including:- releasable stretching means engageable with a mountin structure and operable to stretch carpet from a selecte portion of the mounting structure, and carpet holding means engageable with the mountin structure intermediate said stretching means and sai selected portion of the mounting structure. In a further aspect this invention resides broadly in carpet stretching assembly including:- an elongate mounting structure; anchoring means associated with said mountin structure; releasable stretching means engageable with sai mounting structure and operable to stretch carpet from selected portion thereof, and carpet holding means engageable with said mounting structure intermediate said stretching means and said anchoring means. Suitably the mounting structure includes a ladder type frame adapted to rest stably upon a carpeted surface. Preferably the mounting structure includes a plurality of scaffold frames of universal form assembled together in end to end relationship. Alternatively the mounting structure may include an extendable pole-like assembly adapted to be restrained in substantial linear alignment by carpet engaging stabilising means spaced along said pole-like assembly. The stabilising means are preferably constituted by respective carpet gripping heads. It is preferred that the mounting structure is constructed from aluminium or other light weight material having the required strength characteristics. It is also preferred that the width of each module of the mounting structure and the length thereof be such as will facilitate ready access by stairs, lifts, doors etc to areas where carpet is bein laid. The anchoring means may be a gripping head assembly adapte to releasably grip the carpet or it may be an abutmen adapted to abut a wall or the like at which the carpet i secured. Preferably the abutment means is an end of sai mounting structure. The releasable stretching means and/or the carpet holdin means may include any suitable arrangement whereby a carpe or the like may be gripped or otherwise firmly held with th grip not being broken by the application of pressur thereto. They could for example include an edge grippin device with a friσtional gripping action. However it i preferred that the releasable stretching means and/or sai carpet holding means includes a gripping head assembl adapted to releasably grip the carpet. Suitably th gripping head assembly includes at least one gripping hea having an array of inclined spikes projecting downwardl therefrom. It is, preferred that the gripping head assembl includes at least three said gripping heads arranged suc that one said gripping head is positioned centrally of sai mounting structure and the other said gripping heads ar respectively positioned transversely on either side thereof. The releasable stretching means and/or said carpet holdin means may include actuating means adapted to move said gripping head assembly relative to said mounting structure. The actuating means could for example be remote controlled and servo driven or could be manually operable. Suitably the actuating means includes a ratchet mechanism or a hydraulic jacking mechanism. The releasable stretching means may be fixedly mounted to the mounting structure by separately attaching a portion of the stretching means to the frame so as to permit the member carrying the gripping heads to be moveable relative to the fixedly attached portion. Alternatively the releasable stretching means may be movably mounted on the mounting structure by means of wheels or runners adapted to enable the stretching means to move along the mounting structure. In a preferred embodiment the releasable stretching means and/or said carpet holding means includes:- a frame supporting said gripping head assembly, conveying means on said frame whereby said releasable stretching means , and/or said carpet holding means is moveable relative to said mounting structure, and abutment means engageable with corresponding abutment means on said mounting structure whereby said releasable stretching means and/or said carpet holding means is engageable with said mounting structure. Suitably the conveying means includes a plurality of wheel mounted on said frame and adapted to transport sai releasable stretching means and/or said carpet holding mean across the carpet and above and along said mountin structure, and said abutment means includes at least on transversely extending face adapted to engage a transversel extending member on said mounting structure. The stretching assembly may include calibration mean whereby the degree of stretch may be determined an monitored. The calibration means may be connected to print-out device to provide a printed record. In a further aspect this invention resides broadly in method of stretching laid carpet, said method including:- arranging a mounting structure on the laid carpet; anchoring said mounting structure relative to the lai carpet; releasably connecting stretching means to said mountin means whereby carpet may be stretched away from sai anchoring; actuating said stretching means to stretch a first portion of the carpet, and connecting holding means to said mounting structure intermediate said stretching means and said anchorin whereby the stretched first portion of carpet is maintaine in a stretched state. Preferably the method further includes:- releasably re-connecting said stretching means to sai mounting means beyond said holding means whereby carpet ma be stretched away from said holding means; actuating said stretching means to stretch a furthe portion of the carpet, and re-connecting said holding means to said mountin structure intermediate said stretching means and th previous position of said holding means whereby th stretched further portion of carpet is maintained in stretched state. BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 illustrates a stretching assembly with one form o releasable stretching means attached to a mountin structure; FIGS 2-4 illustrate alternative forms of a releasabl stretching means in accordance with the invention; * FIG 5 illustrates one form of a carpet holding means; FIG 6 illustrates a pole-like mounting structure with stabilising means, and IG 7 illustrates the stages in using the carpet stretching assembly in accordance with the invention. DETAILED DESCRIPTION OF THE INVENTION As can be seen in Figure 1, the stretching assembly include releasable stretching means 11 fixedly attached to th module 51 of a mounting structure. The releasabl stretching means has three gripping heads 12 attached to crossbar 13 by means of spigot mounts 14. The spigot mounts 14 are retained in the crossbar 13 by latches (not shown). The crossbar 13 may be selectively urged away from the mounting frame module 51 by ratchet jacking mechanisms 15, 16 fixed to the leading crossbar 18 of the mounting frame 51 with the ratchet housings 16 welded or otherwise affixed t gusset plates 17 welded to the crossbar 18. An additional central slide mounting 22 is provided by an elongate rod 24 attached to the crossbar 13 being slidably received in a cylindrical housing 23 affixed to a transverse rung 53 an the leading crossbar 18 of the module 51. The slide mounting 22 assists in maintaining structural integrit between the mounting frame module 51 and the crossbar 13. The jacking mechanisms 15, 16 are operated by a common actuating lever 21 connected to the jacking mechanisms by yoke 20 whereby each end of the crossbar 13 is simultaneously advanced. Release means 19 are provided to release the jacking mechanisms so that the gripping heads may be disengaged from the carpet. The mounting frame module 51 has sockets 54 at one end o the side rails 52 for receiving the other male ends 55 o the side rails of a conventional aluminium scaffold frame 6 whereby the effective length of the mounting frame may be increased step wise by selectively adding further scaffold frames 61 in end to end relationship to the mounting frame. In this manner readily available scaffold frames 61 may be obtained to increase the effective length of the mounting frame to any desired length. The male ends 55 are a relatively loose fit whereby the mounting frame may be pivoted upwardly with respect to the connected scaffold frames 61 to enable the gripping heads to be raised for release from the carpet. As can be seen in Figure 2, the releasable stretching means 30 includes a pair of hydraulic rams 32 arranged to advance the gripping heads 12. The hydraulic rams have pistons 33 fixedly attached to the leading cross-bar member 13 with the cylinders 32 being affixed to a second and trailing cross¬ bar member 37. The hydraulic rams 32 include actuating or pumping levers 3.4 adapted to incrementally advance the pistons 33 by repeated operation thereof. Each of the cross-bar members 37 and 13 have a pair of concave wheels 35 mounted thereon to be complementarily engageable with and able to run along the parallel side members 52 of the mounting frame. The wheels 35 are mounted at a slight angle to the vertical such that the stretchin means is able to freely track along the side members 52. As can be seen in FIG 2, the gripping heads 12 have an arra of forwardly inclined depending spines 31 for engaging an gripping the carpet in a conventional manner. The stretching means 30 illustrated in Figure 2 thu comprises a trolley-like assembly adapted to move freel along an extended mounting frame. The cross-bar member 3 carries a pair of pawls 36 hingedly connected theret whereby they may pivot rearwardly to enable the stretchin means 30 to pass across the transverse rungs 53 of th mounting frame and to rest in front of the rung to form a abutment against which the stretching means abut when th hydraulic rams 32 are actuated. The releasable stretching means 70 illustrated in FIG 3 ha a supporting frame 71 mounted on wheels 75 such that th stretching means 70 is able to travel along the laid carpe over the mounting frame 61 as the wheels 75 track along th carpet outside the side rails 52 of the mounting frame 61. The supporting frame 71 has a pair of side members 7 supporting a leading cross member 74 and a trailing cros member 73. The wheels 75 are pivotally mounted a respective ends of the cross members 73 and 74. Th trailing crossmember 73 supports a hydraulic fluid reservoi 82 from which hydraulic fluid is pumped to a hydraulic jac 76 via suitable hosing 83 by the action of pump handle 84 The hydraulic jack 76 is cradled in a supporting arm 7 pivotally mounted on the trailing cross member 73 to rotat about a transverse axis. A mounting structure engagemen bracket 87 depends from the supporting arm 77 so as to b engageable with a transverse rung 53 of the mountin structure 61 in a lowered position of the supporting arm 77. The hydraulic actuated piston 78 is attached to a cross ba 79 which carries three conventional gripping heads 80. Bowing of the cross bar 79 is prevented by a tensionin brace 81 welded to the ends thereof and separated therefro in the central region by struts 88. The gripping head assembly can be raised to an elevated position at which the gripping heads 80 clear the carpet, or can be lowered to a carpet engaging position by the action of a lifting handle 85. The lifting handle 85 is operable through a series of linkages 86 to retain the elevated head assembly in stable equilibrium in an over-centre position. In use the releasable stretching means 70 is rolled along the carpet over the mounting structure and when positioned at an appropriate location to commence stretching the carpet, the cross member 79 and associated gripping heads 80 is lowered to engage the carpet by lowering the lifting mechanism 85. When pressure is applied by pump handle 84 to move the stretching means, the engagement of the gripping heads 80 with the carpet causes the stretching assembly 7 to roll backwards on wheels 75 until the mounting structur engagement bracket 87 bears on and is restrained by transverse rung 53 on the mounting structure 61. Furthe actuation of the pump handle 84 causes the carpet to b stretched. The releasable stretching means 100 as seen in FIG 4 i substantially similar to that illustrated in FIG 3 excep that a pair of transversely spaced hydraulic jacks 101 ar provided instead of a central jack. It will of course be obvious that the various stretchin means illustrated in FIGS 1 to 4 are completel interchangeable in as much as the hydraulic embodiment illustrated in FIGS 2 to 4 could include the arrangement o permanent affixing of one portion of the stretching means t the mounting frame, whilst the ratchet mechanism illustrate in FIG 1 could also be mounted on wheels to provide trolley-like stretching means. * In an alternative embodiment (not illustrated) th arrangement shown in FIGS 3 and 4 is varied so that th gripping head assembly is positioned ahead of the leadin edge of the wheeled support frame thereby enabling th gripping head to abut a wall or skirting board against whic the carpet is to be fixed. FIG 5 illustrates a carpet holding means 111 by means of which carpet stretched by the releasable stretching means is maintained in its stretched condition. A cross bar 112 supports three gripping heads 113 in transverse spaced relation similar to the gripping head assembly of the releasable stretching means. A pair of transversely spaced abutment faces 115 depend from the crossbar 112 and are spaced to abut a transverse rung 53 of the mounting structure 61. The cross bar 112 also supports a pair of wheels 116 and an upwardly extending handle 114. In use, the carpet holding means 111 is positioned behind a releasable stretching means such that the abutment faces 115 abut a transverse rung 53 of the mounting structure 61. When the releasable stretching means is released, the stretched carpet is maintained in its stretched condition by the gripping action on the carpet of the holding means 111. When the releasable stretching means is re-positioned and the carpet restretched to its new position, the carpet holding means 113 can be disengaged from the carpet at its first position by. pivoting the handle 114 forward so that the holding means 111 pivots on the wheels 116 thereby raising the gripping heads 113 and disengaging them from the carpet. The carpet holding means thus clears the mounting structure and is then rolled along the carpet over the mounting structure to its new holding position adjacent the re-positioned stretching means. As seen in FIG 6, the mounting structure may include number of elongated rods 132 adapted to interlock to form a extendable pole-like assembly 131 adapted to carry releasable stretching means 133 along its length. In orde that pressure applied to the column via the stretching mean 133 does not cause buckling and bowing, a number of carpe engaging stablising means 134 are positioned along th length of the mounting structure. Each stablising means 13 includes a pair of transversally spaced gripping heads 13 joined by a bridging element 136 having a central collar o yoke 137 which sits over the elongated rods to preven lateral movement thereof. The collars 137 abut retentio means (not shown) on the mounting structure whereby th bridging element 136 constitutes a transverse rung agains which both the stretching means 133 and a carpet holdin means can bear during stretching operations. FIGS 7(a) to 7(e) illustrate the stages followed in th stretching operation. A length of carpet 151 is laid ou along the area to be carpeted between walls or skirtin boards 156 and 157. A mounting structure 152 is assemble and laid on the carpet along its full length. Stretchin means 153 is then positioned as seen in FIG 7(a) and the carpet stretched between the wall and the stretching means. As seen in FIG 7(b) a carpet holding means 154 is the positioned adjacent the stretching means 153 which are the re-positioned further along the mounting structure. The carpet is then again stretched and the holding mean repositioned as shown in FIG 7(c). As seen in FIG 7(d) th stretching means 153 is repositioned at the end of th carpet run and after further stretching the holding mean 154 can be removed as seen in FIG 7(e). The unstretche portion of carpet, 155 in FIGS 7(a) and 7(b) and 158 in FIGS 7(c) and 7(d), decreases as the process continues. The stretching apparatus in accordance with this invention may be used in numerous ways to stretch carpet in accordance with desirable practices and with the required specifications. Preferably the stretching sub-frames or scaffold frames or modules are laid out and connected to provide a mounting structure which extends across the entire length of the carpet being laid, even if such length is in excess of 50 metres. For example if a pair of stretching means are utilised the carpet can be first stretched across its entire length or across a substantial component of the total length, and then further stretched by utilising a second intermediate stretching means. However it is preferred that a stretching means is used in association with holding means so that the carpet is uniformly and progressively stretched by sequentially applying the stretching means, holding the stretched carpet in place with the holding means and then repeating the steps with the stretching means advanced along the mountin structure. Furthermore, because of the degree of control provided by the present invention and the considerabl broader head which may be used effectively with the present invention, the number of passes required to stretch a given width of carpet can be significantly reduced. Equally it is possible in accordance with the present invention to utilise a fixed stretching means at the end of the carpet and to operate with a pair of travelling stretching means, or with stretching means combined with holding means in the intermediate portions. It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as defined in the following claims.

Claims: CLAIMS 1. A carpet stretching assembly including;- releasable stretching means engageable with a mountin structure and operable to stretch carpet from a selecte portion of the mounting structure, and carpet holding means engageable with the mounting structure intermediate said stretching means and said selected portion of the mounting structure. 2. A carpet stretching assembly including;- an elongate mounting structure; anchoring means associated with said mounting structure; releasable stretching means engageable with said mounting structure and operable to stretch carpet from a selected portion thereof, and carpet holding means engageable with said mounting structure intermediate said stretching means and said anchoring means. 3. A carpet stretching assembly as defined in claim 1 or claim 2, wherein said mounting structure includes a ladder type frame adapted to rest stably upon a carpeted surface. 4. A carpet stretching assembly as defined in claim 3, wherein said ladder type frame includes a plurality o scaffold frames of universal form assembled together in en to end relationship. 5. A carpet stretching assembly as defined in claim 1 o claim 2, wherein said mounting structure includes a extendable pole-like assembly adapted to be restrained in substantial linear alignment by carpet engaging stabilising means spaced along said pole-like assembly. 6. A carpet stretching assembly as defined in any one previous claim, wherein said mounting structure is constructed from aluminium or other light weight material. 7. A carpet stretching assembly as defined in any one previous claim, wherein said anchoring means is a gripping head assembly adapted to releasably grip the carpet. 8. A carpet stretching assembly as defined in any one of claims 1 to 6, wherein said anchoring means is an abutment adapted to abut a wall or the like at which the carpet is secured. 9. A carpet stretching assembly as defined in claim 8, wherein said abutment means is an end of said mounting structure. 10. A carpet stretching assembly as defined in any on previous claim, wherein said releasable stretching mean and/or said carpet holding means includes a gripping hea assembly adapted to releasably grip the carpet. 11. A carpet stretching assembly as defined in claim 7 o claim 10, wherein said gripping head assembly includes a least one gripping head having an array of inclined spike projecting downwardly therefrom. 12. A carpet stretching assembly as defined in claim 11, wherein said gripping head assembly includes at least thre said gripping heads arranged such that one said grippin head is positioned centrally of said mounting structure an the other said gripping heads are respectively positione transversely on either side thereof. 13. A carpet stretching assembly as defined in any one previous claim, wherein said releasable stretching means and/or said carpet holding means includes actuating means adapted to move said gripping head assembly relative to said mounting structure. 14. A carpet stretching assembly as defined in claim 13, wherein said actuating means includes a ratchet mechanism or a hydraulic jacking mechanism. 15. A carpet stretching assembly as defined in any on previous claim, wherein said releasable stretching mean and/or said carpet holding means includes:- a frame supporting said gripping head assembly, conveying means on said frame whereby said releasable stretching means and/or said carpet holding means is moveable relative to said mounting structure, and abutment means engageable with corresponding abutment means on said mounting structure whereby said releasable stretching means and/or said carpet holding means is engageable with said mounting structure. 16. A carpet stretching assembly as defined in claim 15, wherein:- said conveying means includes a plurality of wheels mounted on said frame and adapted to transport said releasable stretching means and/or said carpet holding means across the carpet and above and along said mounting structure, and said abutment means includes at least one transversely extending face adapted to engage a transversely extending member on said mounting structure. 17. A carpet stretching assembly substantially as hereinbefore described with reference to the accompanying drawings. 18. A method of stretching laid carpet, said metho including:- arranging a mounting structure on the laid carpet; anchoring said mounting structure relative to the lai carpet; releasably connecting stretching means to said mountin means whereby carpet may be stretched away from sai anchoring; actuating said stretching means to stretch a firs portion of the carpet, and connecting holding means to said mounting structure intermediate said stretching means and said anchorin whereby the stretched first portion of carpet is maintained in a stretched state. 19. A method of stretching laid carpet as defined in claim 18, said method further including:- releasably re-connecting said stretching means to said mounting means beyond said holding means whereby carpet may be stretched away from said holding means; actuating said stretching means to stretch a further portion of the carpet, and re-connecting said holding means to said mounting structure intermediate said stretching means and the previous position of said holding means whereby the stretched further portion of carpet is maintained in a stretched state. 20. A method of stretching laid carpet substantially a hereinbefore described with reference to the accompanyin drawings.

Inventors: ANASSON NICHOLAS, ANASSON, NICHOLAS
Applicants: ANASSON CARESSE DONEALIA, ANASSON, CARESSE, DONEALIA
Application year: 1991
Main classification: A47G27
IPC codes: A47G27