CA2155786C - Vinyl composition tile heating system - Google Patents

Abstract

A method and apparatus is provided for heating vinyl composition tiles which are then amenable to cutting with a knife along complex contours without damaging the tiles. A stack of heating trays are located within a protective housing.
The housing is supported on wheel means for ease of transport about the worksite and has one open side so that tiles can be loaded onto each of the trays. A discrete electrical heating element heats each tray and tile to a uniform temperature which renders the tile sufficiently elastic to be cut along any desired contour without fracturing. The trays are spaced appropriately so that tiles can be individually seized for cutting by the installer. The combination of the number of trays and the heating element's heat transfer capability enables an installer to repeatedly seize a sufficiently heated tile, re-load the vacant tray, and then seize another heated tile from the next sequential tray on a cyclical, sustainable basis. For added convenience, it is preferable that each tray be provided with a mechanical tile extractor and that the housing contain a cold tile storage compartment.

Description

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CROSS REFERENCE TO RELATED APPLICATION

2 This application is a continuation-in-part of pending application 3 08/193,524, filed 02/08/94.

The present invention relates to a system for heating whole vinyl 6 composition tiles, thereby rendering the tiles elastic and amenable for cutting of 7 complex contours therein without fracture.

g Floor tiles, conlmonly known as vinyl composition tiles ("VCT") are typically 12" by 12" by 1/8" thick. The composition of the tiles makes them brittle at 11 room temperature and elastic at elevated temperatures.
12 In a typical tile installation covering 1000 ft2, about 7.0 hours are required 13 to lay the first 970 of the tiles and a further 60 minutes are required to lay the 14 remaining 30 tiles. As shown in Prior Art Figure 1, remaining tiles a require custom fitting around non-linear features b (such as around circular drains), and along linear 16 multi-stepped contours c (such as around door casings) before they can be installed 17 into corresponding space s. Cutting these complex contours b,c is not possible using 18 a commercial tile cutter which is capable only of performing linear cuts which extend across the entire tile.

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About 2/3 of the time required to custom-fit the remaining tiles a is 2 consumed in heating the tiles (about 1 to 2 minutes per tile) to an sufficiently elastic 3 state to permit cutting with a razor knife. The success of this laborious heating 4 procedure is dependent upon the contour and the lineal length of the cut, and the skill of the installer.
6 To date, heating means such as a hand-held propane torch or a heat 7 gun d (heated air blower made especially for flooring) have been used for heating tile 8 a locally along the proposed lines e for cutting. The heat gun provides a localized g source of heat, with typical exhaust temperatures being dangerously, yet necessarily, hot (up to about 750F).
11 This heating process is very time consuming and often results in inferior 12 results. Disadvantages, associated with the prior art heating means, include:
13 - about 2/3 of the time required to fit custom-cut tiles is consumed 14 simply in an effort to heat only a portion of the tiles;
- a high degree of difficulty is involved in uniformly heating the 16 entire length of a long cutting line e without locally overheating 17 one area of the tile, risking physical or aesthetic damage to the 18 tile a, or leaving other areas cool and subject to fracture. The 19 installer must consider multiple variables including the size of theproposed cut, the temperature of the heat source, the distance of 21 the heat source to the tile, and the speed at which the heat 22 source is swept over the tile;

2lss786 -- commercial heat guns d typically require special high amperage 2 circuits (20 Amp) not available at most worksites, requiring the 3 use of adapters f coupled to common 15 Amp circuits, resulting 4 in frequent blown circuits;
s - the high exhaust temperature of the heat gun is a safety hazard 6 for the installer, while in use and also when idle. Usually the 7 installer will not attempt to hold the tile during heating to avoid 8 exposure to the heat. Further, heat reflected from the tile causes g discomfort for the installer; and - there is a high potential for damage (heat discoloration and fire) 11 to workplace structures, such as walls g against which tiles a are 12 often supported and to surfaces h upon which the heating means 13 d are temporarily rested.
14 Therefore, there has long been a need for an improved system of cutting 15 VCT flooring tiles which demonstrates a high rate of success, is more convenient and 16 poses a reduced risk to personnel, the workplace, and the tiles themselves.

SUMMARY OF THE INVENTION
2 In accordance with the invention, a vinyl composition tile ("VCT") heating 3 system is providing for heating VCT tiles which arel when hot, amenable to cutting 4 along complex contours without damaging the tiles.
In one aspect of the invention, a heating assembly is provided. More 6 particularly, a stack of vertically spaced heating trays is located within and supported 7 by a protective housing. The housing is supported on wheel means for transport 8 about the worksite and has one open side so that tiles can be loaded onto each of the g trays. Discrete, electrical heating elements heat the trays for conductively heating the tiles to a uniform elevated temperature, at which the tile is sufficiently elastic to be cut 11 with a knife along any desired contour without damage to the tile. The trays are 12 spaced appropriately so that tiles can be individually seized for use (cutting) by the 13 installer. The combination of the number of trays and the heating element's heat 14 transfer capability enables an installer to repeatedly seize a sufficiently heated tile, re-load the vacant tray, and then seize another heated tile from the next sequential tray 16 on a cyclical, sustainable basis.
17 Use of the apparatus of the invention results in increased VCT tile 18 installation rates, a reduced impact on the worksite and reduced incidence of damage 19 to the custom-cut tiles.
In one broad aspect then, a VCT tile heating assembly is provided 21 comprising: a stack of vertically spaced, horizontally oriented heating trays, each tray 22 having a bottom surface, each tray being sized to support a tile across substantially 23 its entire bottom face area and provide an upper conductive heat transfer surface 24 which is in contact with substantially the entire bottom surface of the tilel so that 2lss786 substantially the entire area of the tile may be simultaneously and uniformly heated, 2 the spacing between trays being appropriate to permit the installer to readily seize and 3 remove each tile for cutting; a housing for enclosing and supporting the stack of 4 heating trays, the housing having at least one open side for accessing tiles, the 5 housing being supported on wheel means for rolling movement; and a plurality of 6 discrete heating elements, each being in thermal engagement with a tray's bottom 7 surface, for heating the trays of the stack to a sufficient temperature so that each tile's 8 temperature is raised sufficiently, by conductive addition of heat substantially uniformly g across its width and length, so that the tile may be cut along a desired contour line 10 without fracturing.
11 The heating apparatus lends itself to an efficient and safe method for 12 heating VCT tiles for cutting along a complex contour line comprising:
13 - initially loading a plurality of original tiles onto a stack of heated 14 trays, one tile per tray;
- heating each tile substantially uniformly throughout so that the 16 entire tile is sufficiently elastic to be readily cut along the contour 17 line without fracturing;
18 - removing a first heated tile from its respective heating tray for 19 cutting by an installer, leaving the heating tray temporarily vacant;
- loading a first replacement tile onto the vacant heating tray for 21 heating of the first replacement tile;
22 - heating the first replacement tile substantially uniformly 23 throughout;

2ls5786 - repeating the steps of removing, loading, and heating tiles from 2 different trays in sequence at each repeat, so that by the time all 3 of the originally heated tiles have been removed, the first4 replacement tile is now uniformly heated, and so on for each sequentially replaced tile so that a tile is always uniformly heated 6 and available for cutting by the installer.

8 Figure 1 is a perspective view of a typical vinyl composition tile flooring g installation using the system of the prior art;
Figure 2 is a front view of the tile heating assembly of the present 11 invention, showing a stack of heating trays located within and supported by a 12 protective, wheeled housing;
13 Figure 3 is a cross sectional view of the tile heating assembly of Figure 14 2, taken along line lll-lll, showing the loading and selecting of tiles; and Figure 4 is an exploded perspective view of a heater, a heating tray, a 16 tile and a tile extracter. The housing has been mostly cut away.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
2 Having reference to Figures 2 and 3, a heating assembly 1 for the 3 heating of vinyl composition ("VCT") tiles is provided. VCT tiles typically comprise a 4 composition of polyvinyl chloride, resin binder and fillers.
Specificallyl the assembly 1 comprises a tile receiving stack 2 mounted 6 within and supported by a protective housing 3. The housing 3 is open on one side 7 4 to permit unrestricted access to the stack 2. The housing 3 is supported on wheel 8 means 5 such as castersl for enabling rolling movement on a worksite floor 6.
g The stack 2 comprises a plurality of vertically spaced, horizontally oriented heating trays 7. Each tray is sized to support substantially the entire area of 11 one tile. Individual tiles 9 are placed onto each of the trays 7. Each tray 7 is spaced 12 sufficiently apart from another so that the tiles 9 can be readily accessed with an 13 installer's hands.
14 Each tray 7 is thermally engaged with a heating element 11 positioned at its bottom surface 12. Each heating element 11 is coextensive with the tile-16 supporting area of the tray 7 and is contiguous with its bottom surface 12. The 17 heating element 11 is operative to produce heat evenly and uniformly from its entire 18 top surface 13.
19 More particularly, the tray 7 is formed of light gauge (0.074" thick) aluminum and the heating element 11 comprises a flexible silicone composite sheet 21 within which is encapsulated a resistive electrical heater wire (not shown). The 22 silicone composite sheet is adhesively secured to the tray's bottom surface 12.

A suitable heating element 11 for this purpose is available from Ogden 2 Manufacturing Co., Arlington Heights, Illinois, under Part No. RM 574-026 ORANGE.
3 This element is a 10" x 10" x 1/16" thick, adhesive backed, 120V - 350 watt unit. It 4 iS compatible with the power supply commonly available at the worksite, which is typically 110 volt AC and 15 amperes.
6 In summary then, the heating element 11 is operative to supply heat 7 uniformly and evenly from its entire top surface 13 to the heating tray 7 which in turn 8 uniformly heats the tile 9 across its full area.
g The heating element 11 is associated with a thermostat 14 for controlling its heat output. The thermostat 14 can be adjusted so that the temperature of the tile 11 9 may be raised sufficiently so that it may be cut without fracturing.
12 The housing 3 forms a bottom storage container 15 for retaining a stack 13 of cold tiles. It also functions to provide a cool exterior surface, for the safety of the 14 installer.
Having reference once again to Figures 2 and 3, in operation, each of 16 the trays 7 of the assembly 1 is loaded with a tile 9. The heating elements 11 are 17 energised, using thermostats 14. In a short while, each of the tiles 9 is heated to a 18 uniform temperature (about 120 to 150F) at which point the entire tile is sufficiently 19 elastic to be cut (typically with a razor knife) along a contour line (not shown) without 2 0 fracturing.
21 At these relatively low temperatures, achieving substantial uniformity of 22 temperature across the tile is important. The optimal tile temperature may be 23 determined, prior to commencing installation, by trial and inspection.

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When a tile 9 is needed by the installer, one is readily selected and 2 removed from its tray 7, by access through the open side 4 of the housing 3. The 3 installer can re-load the vacant tray 7 with a replacement tile. The heated tile 9 can 4 be immediately and easily cut along the desired contour line.
If the rate of installation is slow, then it is possible for the replacement 6 tile to be heated uniformly and to a sufficient temperature by the time the installer 7 requires another tile. Normally however, an installer will require tile at a faster rate 8 than the heating element 11 can heat the individual replacement tile 9.
g Therefore, in the normal situation, when an installer requires heated tiles 0 on more a rapid and frequent basis, the installer may select an already heated tile 9 11 from one of the additional trays 7. Optimally and most conveniently, the installer 12 would select the next adjacent tile. The vacant tray would be loaded with a 13 replacement tile.
14 The installer can repeat this procedure, selecting additional heated tiles from the next sequential tray as required. A replacement tile would be loaded back 16 onto the vacant tray.
17 The replacement tiles, which the installer has been re-loading, are heated 18 while the installer cuts and fits heated tiles. Given enough time, these replacement 19 tiles become heated and are thus available for repeated selection and use on a sustainable, sequentially cyclic basis.
21 If an installer can cut and fit a tile in 0.5 minutes, and the heating 22 element is capable of heating a tile to a cutable uniform temperature in 1.5 minutes, 23 then the minimum number of trays required to always provide a heated tile on a 24 sustainable basis is 1.5/0.5 - 3 trays.

215s786 In the embodiment shown in Figure 4, a mechanical tile extractor 16 is 2 provided at each tray for assisting in the removal of the heated tile 9 from the tray.
3 Each extractor 16 is mounted either from the top of the housing 3 or the adjacent tray 4 7 above, and is sufficiently spaced above each tray 7 for facilitating loading of a tile 5 9 therebetween. The extractor 16 comprises a guided pull bar 17, having a grasping 6 end 18, extending outside the housing's open side 4, and a tile engaging end 19, 7 terminating at the rear of the housing 3. The pull bar 17 is movable, between a 8 inwardly spring-biased position A at rest and a tile-selecting position B, when pulled g by the grasping end 18. The tile engaging end 19 is fitted with a transverse rake 20 10 which depends downwardly sufficiently to engage the tile 9 without interference with 11 the tray 7.
12 When the pull bar 17 is pulled to the tile-selecting position B, the rake 13 20 pushes the tile 9, so that it is displaced a short distance out of the housing's open 14 end for easier and safer seizing of the tile by the installer. When released, the pull bar 15 17 retracts to its rest position A, to permit re-loading of the tray with a replacement 16 tile.
17 In summary, the present invention is characterised by the following 18 advantages over the prior art:
19 - by providing a stack of heating trays and-tiles and by accessing tile in a sequential and cyclical manner, a continuous and 21 sustainable supply of heated tiles is available to the installer, 22 eliminating the valuable time previously lost to individual heating 23 of tiles;

-- tiles can be maintained in a heated state and yet can be readily 2 and conveniently accessed though the open side of the housing 3 without interrupting the installer's pace;
4 - the uniformly heated tile is cut more easily along the entire length of a contour line and with greater success;
6 - the system is maintained at non-hazardous temperatures, is 7 contained and does not impact adversely on the worksite; and 8 - the wheeled housing can be readily rolled to a convenient position g adjacent the worksite, while further providing a supply of additional tiles.
11 Further, as an illustration of the economic benefits of the present 12 invention to a tile installer, the foilowing example is provided. For a typical tile 13 installation covering 1000 ft2, the following economics were observed:
14 Prior Present Art Invention 16 Uncut tiles (# tiles) 970 970 17 Uncut Installtime req'd (hours) 7.0 7.0 18 CutTiles (# tiles) 30 30 19 Cut Install time required (hours) 1.0 0.33 Install time saved (hours) 0.0 0.67 21 Labor cost (2 men) ($15/hr) $240.00 $219.90 22 Labor savings 0.00 $20.10 23 Laborsavings 8 %
24 Job income $400.00 $400.00 Profit earned 160.00 180.10 26 Increased profits 13 %

28 It is clear that the more challenging the installation (geometrically 29 complicated residential and smaller areas), the more advantageous is the present invention to the installer.

Claims (7)

1. An assembly for heating vinyl composition tiles for cutting by an installer comprising:
a stack of vertically spaced, horizontally oriented heating trays, each tray having a bottom surface, each tray being sized to support a tile across substantially its entire bottom face area and provide an upper conductive heat transfer surface which is in contact with substantially the entire bottom surface of the tile, so that substantially the entire area of the tile may be simultaneously and uniformly heated, the spacing between trays being appropriate to permit the installer to readily seize and remove each tile for cutting;
a housing for enclosing and supporting the stack of heating trays, the housing having at least one open side for accessing tiles, the housing being supported on wheel means for rolling movement; and a plurality of discrete heating elements, each being in thermal engagement with a tray's bottom surface, for heating the trays of the stack to a sufficient temperature so that each tile's temperature is raised sufficiently, by conductive addition of heat substantially uniformly across its width and length, so that the tile may be cut along a desired contour line without fracturing.

2. The assembly as set forth in claim 1 wherein:
each heating element is co-extensive with the tile-supporting area of the heating tray and produces heat evenly and uniformly across its top surface.

3. The assembly as set forth in claim 2 comprising thermostatic control means for controlling the heat output of each heating element.

4. The assembly as set forth in claim 3 wherein the housing forms a container for containing a stack of cold tiles.

5. The assembly as set forth in claims 1, 2, 3 or 4 wherein:
the stack has three trays and the heating element is capable of supplying sufficient heat so that, if the stack is originally loaded with tiles for heating and then is loaded with a replacement tile whenever a heated tile is removed and the heated tiles are removed in a sequential manner, then by the time all of the originally heated tiles have been sequentially removed, the replacement tile will be sufficiently and uniformly heated for cutting.

6. The apparatus as recited in claims 1, 2, 3 or 4, comprising:
a mechanical tile extracting means, associated with each tray, for engaging a heated tile, at its end remote from the housing open side, and pulling it out through the housing's open side whereby the tile can be seized by the installer.

7. A method for preparing vinyl composition tiles for cutting along a contour line by an installer comprising:
(a) initially loading a plurality of original tiles onto a stack of heated trays, one tile per tray;
(b) heating each tile substantially uniformly throughout so that the entire tile is sufficiently elastic to be readily cut along the contour line without fracturing;
(c) removing a first heated tile from its respective heating tray for cutting by an installer, leaving the heating tray temporarily vacant;
(d) loading a first replacement tile onto the vacant heating tray for heating of the first replacement tile;
(e) heating the first replacement tile substantially uniformly throughout;
(f) repeating the steps (c) - (e) by removing, loading, and heating tiles from a different tray in sequence at each repeat, so that by the time all of the originally heated tiles have been removed, the first replacement tile is now uniformly heated, and so on for each sequentially replaced tile so that a tile is always uniformly heated and available for cutting by the installer.