AU2009100932A4

AU2009100932A4 - Cast-in plate void former

Info

Publication number: AU2009100932A4
Application number: AU2009100932A
Authority: AU
Inventors: Gavin A. Kalitis; Damon A. Washington
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 2009-09-14
Filing date: 2009-09-14
Publication date: 2009-10-29
Anticipated expiration: 2017-09-14

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR AN INNOVATION PATENT Name of Applicant: Illinois Tool Works Inc. Actual Inventors: Damon A. WASHINGTON Gavin A. KALITIS Address for Service: DAVIES COLLISON CAVE, Patent Attorneys, of I Nicholson Street, Melbourne, Victoria 3000, Australia Invention Title: Cast-in plate void former The following statement is a full description of this invention, including the best method of performing it known to us: P 1OPER\RSH\30836099-innv dae.7/9/2009 CAST-IN PLATE VOID FORMER The present invention relates to a void former for a plate to be cast into a concrete panel or other component. 5 In the erection of structures from precast concrete wall panels, adjacent panels in the structure can be connected by means of metal plates cast into the surface of the panels at or adjacent their edges, with a connection plate extending between the two adjacent cast-in plates and being fixed thereto by example by welding or bolting. The cast-in plates are 10 recessed sufficiently into the depth of the panel to ensure that when the connection plate is applied it does not project from the surface of the panel. Cast-in plates incorporating threaded ferrules may also be incorporated for other purposes at suitable positions within the surface of the panel. Prior to casting, the plates are incorporated at required positions relative to the reinforcement and the surface of the plate at that time is covered by a void 15 former which, after casting and curing of the concrete, is removed to expose the outer face of the cast-in plate. Void formers for this purpose typically comprise a plastic block of a shape corresponding to that of the plate with permanent magnets to hold the block in position on the plate. However after casting, the blocks tend to be difficult to remove and removal often involves the use of a crowbar or large screwdriver to prise the block away 20 from the plate and damage to the void former itself and the surrounding concrete frequently occurs. The present invention in its preferred embodiment relates to a void former designed to facilitate its removal from the plate after casting and which not only saves time but also 25 alleviates damage to the void former and panel during removal. According to one aspect of the invention there is provided a void former for use with a plate to be cast into a concrete component, the void former being apertured for engagement with a removal tool whereby engagement of the tool within the aperture to secure the tool 30 permits removal of the void former by use of the tool to pull the void former away from the plate after casting.

P:\OPER\RSH\30369-innovdoc-7j9/20U9 -2 In a preferred embodiment the void former is in the form of a block having an inner face with a peripheral shape corresponding to that of the plate, the block being apertured within a central part thereof for positive engagement with the removal tool. 5 Advantageously the aperture is in the form of a slot opening into a recess within the inner face of the block whereby upon insertion of an inner end portion of the tool through the slot, the inner end portion lies within the recess. The recess is so configured that after insertion of the inner end portion of the tool through the slot and into the recess, rotation of 10 the tool displaces the inner end portion relative to the slot to provide a positive lock between the tool and the block for the purposes of removal of the void former. Advantageously the slot opens into a recess formed within the outer face of the block to receive a removable cap for closing the recess and thereby shielding the slot during 15 casting. Advantageously the void former has a seal or means for carrying a seal around the outer periphery of the inner face for sealing with the plate to prevent ingress of concrete during casting. In an embodiment designed for application to a plate to be incorporated within the 20 lower face of the panel against a casting bed, the void former also has a seal or means for carrying a seal around the periphery of the outer face to prevent ingress of concrete between the outer face and a casting bed during casting. Advantageously sides of the block extending between its inner face and outer face incline 25 outwardly from its lower face to aid removal of the block during casting. According to another aspect of the invention there is provided a removal tool for use with a void former as defined above, the tool having a handle and an operative end portion engageable within the aperture to secure the tool to the void former. 30 According to yet another aspect of the invention there is provided a removal tool for use P:\OPER\RSH\3083609.nnvdoc. 7/9/2009 -3 with a void former as defined above, the tool having a shank with a handle at an outer end thereof and a transverse pin at an inner end thereof for engagement through the slot. Embodiments of the invention will now be described by way of example only with 5 reference to the accompanying drawings in which: Figure 1 is a plan view of the upper or outer face of a void former according to a first embodiment of the invention; Figure 2 is a view showing the lower or inner face; Figure 3 is a perspective view from above; 10 Figure 4 is a perspective view from beneath; Figure 5 is a section on line A-A of Figure 1; Figure 6 is a section on line B-B of Figure 1; Figure 7 shows a removal tool for the void former; Figure 8 is a perspective view showing the outer face of a void former in 15 accordance with a second embodiment of the invention; Figure 9 is a perspective view showing the inner face; Figure 10 is a view showing the inner face; Figure 11 is a section on line A-A of Figure 10; Figure 12 is a section on line B-B of Figure 10; 20 Figure 13 is a view showing the upper or outer face of a void former in accordance with a third embodiment of the invention; Figure 14 is a view showing the lower or inner face; Figure 15 is a section on line A-A of Figure 13; and Figure 16 is a section on line B-B of Figure 13. 25 A void former in accordance with a first embodiment of the invention as shown in Figures 1 to 6 is in the form of a block 2 of a suitable plastics material, polypropylene for example. The void former of this embodiment is designed for use in conjunction with a cast-in plate to be set into the upper face of a concrete panel being cast on a casting bed. As such it is 30 the lower face 4 of the block 2 which in use, will be adjacent the surface of the cast-in plate and as such its length and breadth dimensions correspond to those of the plate. The P OPERRSH\30838609-ino doc-79009 -4 depth of the block 2 corresponds to the depth to which the plate is to be recessed into the surface of the panel. As will be seen from Figures 1 to 6, the sides 6 of the block 2 incline outwardly from its lower face 4 to its upper face 8 and this aids removal of the block 2 following casting. It will be understood that the presence of this inclination along each of 5 the four sides 6 of the block means that this embodiment is designed for cast-in plates which are in set inwardly relative to the edge of the panel and thus relative to the formwork in place during casting of the panel. An alternative embodiment is provided for situations where the edge of the plate is to be substantially coincident with the edge of the panel and thus with the formwork in place during casting; this embodiment will be described 10 subsequently. Permanent magnets 10 are mounted within the lower face 4 of the block 2 in order to retain the block in position against the plate during casting. The centre portion of the block is penetrated by an aperture to permit positive engagement of the block with a removal tool which is inserted into the aperture after casting to enable 15 removal of the block by applying a direct pull on the tool. The tool is shown in Figure 7 and comprises a shank 12 having a handle 14 at its outer end and a transversely-directed pin 16 at its inner end. The aperture in the block is in the form of a slot 18 which opens onto the upper face 8 of the block but is recessed below that face of the block for reasons to be explained, the slot 18 being of a shape to permit passage of the lower end portion of 20 the tool consisting of the transverse pin 16 and adjacent part of the shank 12. The slot 18 opens into a recess 20 at the underside of the block, the recess 20 being so shaped that when the lower end portion of the tool is inserted through the slot 18, rotation of the tool through 900 about the axis of its shank causes the transverse pin 16 to rotate out of alignment with the slot 18 and into engagement with edges 20a of the recess 20 to prevent 25 further rotation. It will of course be understood that with that rotation of the tool, the tool is positively locked to the block 2 so that a direct upwards pull on the tool will remove the block away from the plate after casting. As mentioned previously, at its upper end the slot 18 opens into a recess in the upper face 30 of the block; this recess can best be seen in Figure 3 and is designated 22. The function of the recess 22 is to receive a removable plug of corresponding shape to that of the recess to P:OPER\RSH\30838609-inn ovdoc7)09/2009 -5 prevent penetration of concrete into the recess and thereby through the slot 18 during casting. The plug is formed from a suitable plastics material and to enable its easy removal after casting, the lower end of the shank of the tool carries a short spike 24 which is grooved or threaded to penetrate the cap to enable it to be pulled out of the recess and 5 thereby expose the slot 18. Advantageously, a rebate or other recess 26 is formed around the outer periphery of the lower face 4 of the block to receive a seal, for example in the form of a strip of neoprene, so as to prevent ingress of concrete during casting between the lower face of the block and 10 the face of the plate. The central zone of the lower face 4 is slightly recessed relative to the outer edge of the face to create a narrow air void relative to the surface of the plate to reduce suction likely to resist removal of the block. The void former shown in Figures 1 to 6 is designed for application to a plate to be 15 incorporated within the upper, exposed, face of the panel during casting. Figures 8 to 12 show an embodiment designed for application to a plate to be incorporated within the lower face of the panel during casting, in other words the face of the panel against the casting bed. This embodiment is substantially similar to that of Figures 1 to 6 except that an additional set of magnets 30 is incorporated into the outer face 8 of the block (the face 20 of the block which will be in contact with the casting bed) in order to retain the block in a position on the casting bed by magnetic engagement therewith. This embodiment also features a rebate or other recess 32 around the periphery of the outer face 8 for a sealing strip to prevent penetration of concrete between the outer face and the casting bed. 25 Figures 13 to 16 show an embodiment of the void former in which one of its side edges 6a extends perpendicularly between the lower and upper faces 4,8 rather than inclined. This form of void former is intended for application to a plate having an edge coincident with the edge of the panel, the perpendicular side 6a of the block enabling it to abut directly against formwork which defines that edge on casting. This configuration with a single 30 perpendicular side can also be adopted in a version similar to that shown in Figures 8 to 12 for installation at the underside of the panel during casting.

P:\OPERRSHUWO386An-nn ovdooM-/9209 -6 The configuration of the void former for use with the tool enables the void former to be removed by use of the tool significantly more easily than prior void formers as discussed at the outset. Moreover the removal process is unlikely to result in damage to either the 5 surrounding concrete or the void former itself thereby enabling reuse of the void former. The embodiments have been described by way of example only and modifications are possible within the scope of the invention. For example the removal tool and its co operation with the void former may differ from that shown; for example an alternative 10 form of coupling for achieving positive engagement between the tool and void former to enable removal of the void former, may be incorporated.

Claims

1. A void former for use with a plate to be cast into a concrete component, the void former being apertured for engagement with a removal tool whereby engagement of the 5 tool within the aperture to secure the tool permits removal of the void former by use of the tool to pull the void former away from the plate after casting.

2. A void former according to claim 1, wherein the void former is in the form of a block having an inner face with a peripheral shape corresponding to that of the plate, the 10 block being apertured within a central part thereof for positive engagement with the removal tool.

3. A void former according to claim 2, wherein the aperture is in the form of a slot opening into a recess within the inner face of the block whereby upon insertion of an inner 15 end portion of the tool through the slot, the inner end portion lies within the recess.

4. A void former according to claim 3, wherein the recess is so configured that after insertion of the inner end portion of the tool through the slot and into the recess, rotation of the tool displaces the inner end portion relative to the slot to provide a positive lock 20 between the tool and the block for the purposes of removal of the void former.

5. A void former according to claim 3 or claim 4, wherein the slot opens into a recess formed within the outer face of the block, the void former further comprising a removable cap for closing that recess and thereby shielding the slot during casting. 25

6. A void former according to any one of claims 2 to 5, having a seal or means for carrying a seal around the outer periphery of the inner face for sealing with the plate to prevent ingress of concrete during casting. 30

7. A void former according to any one of claims 2 to 6, having a seal or means for carrying a seal around the periphery of the outer face to prevent ingress of concrete P.OPER\RSH\30538609-innv do-7/09/2009 -8 between the outer face and a casting bed during casting.

8. A void former according to any one of claims 2 to 7, wherein at least some of the sides of the block between its inner and outer faces are outwardly inclined. 5

9. A void former according to any one of claims 1 to 8, having one or more magnets for attaching the void former to the plate to retain the plate during casting.

10. A void former according to any one of claims 1 to 9, having one or more magnets 10 for securing the void former to a casting bed.

11. A removal tool for use with a void former according to claim 1 or claim 2, the tool having a handle and an operative end portion engageable within the aperture to secure the tool to the void former. 15

12. A removal tool according to claim 11, wherein the handle and operative end portion are at opposite ends of a shank of the tool.

13. A removal tool for use with a void former according to any one of claims 3 to 5, the 20 tool having a shank with a handle at an outer end thereof and a transverse pin at an inner end thereof for engagement through the slot.

14. A removal tool according to claim 13, wherein the inner end of the shank also includes a spike for removal of the cap after casting.