Note: Descriptions are shown in the official language in which they were submitted.
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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.
4 FIELD OF THE INVENTION
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.
8 BACKGROUND OF THE INVENTION
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;
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- 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.
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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
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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;
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- 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.
7 BRIEF DESCRIPTION OF THE DRAWINGS
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.
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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.
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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.
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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;
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- 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 %
27
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.
12
