US 3395453 A
Description (OCR text may contain errors)
E. F. PRATER CARPET CUTTER Aug. 6, 1968 2 Sheets-Sheet 1 Filed April 28, 1967 FIG. 1.
m RT 6 TR P F N5 L m E N W 7 H w V 5 Haze/s, K150 P035251. L &/(/?N United States Patent 3,395,453 CARPET CUTTER Earle F. Prater, Long Beach, Calif., assignor to Roberts Consolidated Industries, Inc., City of Industry, Calif., a corporation of California Filed Apr. 28, 1967, Ser. No. 634,601 5 Claims. (Cl. 30-293) ABSTRACT OF THE DISCLOSURE A tool for trimming carpet, including a base plate for sliding over the top of the carpet along an edge to be trimmed, and a blade holder pivotally connected to the base plate and supporting a pair of oppositely oriented, downwardly inclined carpet-cutting blades.
Disclosure The present invention relates to carpet trimming and cutting devices and, more particularly, to an improved device for trimming the edge of a cushion back carpet when laid on a floor.
The term cushion back carpeting is applied generally to carpeting having a sponge or foam rubber backing bonded directly to the nap of the carpeting. Such cushion back carpeting is installed by coating the floor with a suitable adhesive material and then laying the carpeting flat over the adhesive on the floor. As the adhesive dries, it firmly connects the sponge or foam rubber backing to the floor to securely hold the carpet in place.
Where cushion back carpeting is to extend wall to Wall, it is extremely important that the edges thereof fit snugly but not too tightly against the walls at and immediately above the floor. In particular, if the carpeting is too long or wide and the excess is forced against the walls, transverse forces are exerted on the foam or sponge backing which eventually cause the backing to separate from the floor at a point spaced from the wall and a wrinkle to be produced in the carpeting. If the carpeting is too short or if its edges do not follow the contour of the walls, gaps are produced between the walls and the edges of the carpeting which are unsightly and permit dirt and other debris to collect along the junctions of the floor and walls and to work their way under the carpeting.
Since carpeting does not come precut to the exact dimensions of a room and since walls invariably include minor surface irregularities, to produce the desired snug fit between the edges of a cushion back carpet and the walls of a room, it is necessary during installation of the carpeting to cut and trim the edges to follow the exact contour of the walls adjacent the floor. Carpet cutting or trimming tools are employed for this purpose and, generally speaking, comprise a flat base plate and a blade holder assembly. The base plate is designed to slide over and press downwardly on the top of the carpeting and to carry the blade holder assembly. The blade holder assembly, in turn, carries one or more horizontal blades and is designed to cut upwardly turned carpeting along a plane parallel to the floor. In this regard, and during carpet installation, edge portions of the carpeting are folded upwardly along the walls at the floor edges to follow the general contour of the walls. The cutting tool is then moved tightly over the carpet and against the upwardly turned edge portions to follow the contour of the wall. As the tool is moved, the carpet is cut by the horizontal blade along the plane parallel to the floor.
For conventional carpeting, the foregoing operation produces a substantially squared carpet edge which will butt against the adjacent wall. Such is not the case however, for cushion back carpeting. In particular, when 3,395,453 Patented Aug. 6, 1968 'ice cushion back carpeting is folded at the edge of a floor to follow the contour of a wall prior to cutting, the nap and the upper surface of the backing are compressed while the bottom of the backing is stretched. After cutting with a conventional horizontal blade assembly, the nap and upper surface of the backing expand laterally while the bottom portion of the backing contracts, producing an inwardly inclined edge which will not butt squarely and snugly against the adjacent wall. Accordingly, dirt and other debris is free to work its way under the carpeting and to cause the bond between the adhesive and the backing to eventually break down. This, in turn, permits undesired movement of the carpet, further destroying the connection of the carpet to the floor and with it the under surface of the cushion backing. Alternatively, the carpeting may be out long in an attempt to compensate for the inclined nature of the resulting carpet edge. This, however, results in a condition where the nap and major portion of the backing are transversely compressed at the wall and eventually produces wrinkles in the carpeting near the wall.
In view of the problems associated with the trimming of cushion back carpeting with conventional tools, it is an object of the present invention to provide an improved device for trimming the edge of cushion back carpeting which will produce squared carpet edges adapted to fit snugly against adjacent walls.
Another object of the present invention is to provide an improved carpet trimming device which is easily adjustable to permit its cutting blades to cut at different heights above the floor and at different angles to insure a squared carpet edge and snug fit against an adjacent wall for cushion back carpeting of different thickness and backing types.
A further object of the present invention is to provide a carpet trimmer of the foregoing character which is adapted to handle different type blades and is adjustable to permit control of the amount of projection of the blades such that the trimmer may efficiently trim carpets of different thickness.
Still another object of the present invention is to pro vide an improved cushion back carpet cutting device which will follow the surface of an adjacent wall to insure that the resulting carpet edge closely follows the contour of the wall.
A still further object of the present invention is to provide an improved cushion back carpet trimmer which is adapted to trim campet as it is moved in either a forward or a rearward direction.
Another and more specific object of the present invention is to provide an improved carpet trimmer including a base plate for riding over the top surface of a cushion back carpet adjacent an edge thereof and having a blade holder pivotally connected thereto for vertical swinging movement such that the blade canried thereby may be adjusted vertically to cut the carpet at dilferent heights above the base plate and at an angle which will insure a squared carpet edge for fitting snugly against an adjacent wall.
The foregoing as well as other objects and advantages of the present invention may be more clearly understood by reference to the following detailed description when considered with the drawings which, by way of example only, illustrate a form of carpet trimmer embodying the features of the present invention.
In the drawings:
FIG. 1 is a side view of the carpet trimmer, partially in section, illustrating the manner in which the trimmer severs the upwardly turned edge of a cushion 'back carpet along a wall to produce a squared carpet edge which will butt snugly against the wall;
FIG. 2 is a top view of the carpet trimmer taken along the line 2-2 in FIG. 1;
FIG. 3 is a fragmentary sectional view taken along the line 3-3 in FIG. 2; and
FIG. 4 is a fragmentary sectional view taken along the line 44 in FIG. 2.
In the drawings, the carpet-cutting or trimming tool is represented generally by the numeral 10, and is adapted to slide over the top of a cushion-back carpet 12 and tightly against an upturned edge portion 14 hearing against a wall 16. The tool is designed to sever the edge portion 14 on a downwardly inclined angle adjacent the carpet fold. By cutting on such a downward angle, the tool 10 compensates for the previously referred to contraction and expansion of a backing 18 and nap 20 of the cushion back carpet 12 and produces a substantially squared carpet edge for butting snugly against the wall 16. The tool 10 is also adjustable to cut cushion back carpeting of different backing types and thicknesses and in each instance to produce a substantially squared carpet edge.
To accomplish the foregoing, the tool 10 includes a blade carrying attachment 20 which may be attached to different forms of handle mechanisms, such as 22, and which therefore may be sold as a separate item. Generally speaking, the blade carrying attachment 20 comprises a base 24, a blade holder 26, and an adjustment device 28.
The base 24 includes a generally flat rear portion 30 and a generally fiat front portion 32 slightly below the level of the rear portion and connected thereto by an inclined portion 34. The front portion 32 includes upturned ends 36 and is designed to slide over and in contact with the top surface of the carpet 12, with an upstanding guide 38 bearing tightly against the carpet edge portion 14 to follow the contour of the wall 16 adjacent the floor 39.
As illustrated most clearly in FIG. 2, the guide 38 preferably is a vertical flange extending upwardly from a midportion of the base 24 with rearwardly converging right front and left rear portions. Thus constructed, as the guide 38 is moved firmly along the carpet edge portion 14, it bears tightly against the edge portion and hence the wall 16 at two spaced points which, as will be described in detail hereinafter, are forward of the blade severing the carpet. This insures that the tool 10 closely follows the contour and any irregularities in the surface of the wall 16 adjacent the floor 39 and that the resulting carpet edge will likewise closely follow the contour of the wall surface.
The rear portion 30 of the base 24 is designed for connection to the handle mechanism 22 which, by way of example only, is illustrated as being of the form described in US. Letters Patent No. 2,772,474, issued Dec. 4, 1956. Although details of the handle mechanism 22 may best be understood by reference to the patent, for purposes of this specification, the rear portion 32 is disposable between any two adjacent spacer plates 40 of the handle mechanism and is provided with a pair of spaced stud receiving slots 42 which engage studs 44 extending upwardly from a base plate 46 of the handle mechanism. Downwardly struck attachment locking tabs 48 (FIGS. 1 and 2) provided on the under surface of the rear portion 32 extend over the rear edge of the supporting spacer plate 41] to resist outward movement of the base 24 and hence the attachment 20 upon connection to the handle mechanism 22. In this respect, the spacer plates 40 are locked firmly against the top and bottom of the rear portion 30 by turning knurled nuts 50 on the threaded studs 44 tightly against the top of the spacer plates.
In addition to the spacer plates 40 and base plates 46, the [handle mechanism 22 includes an upwardly extending handle 52, adapted to be grasped by a carpet installer during operation of the tool 10 to sever the edge 4 portion 14 of the carpet 12. The handle 52 may be connected to the base plate 46 by any suitable means such as screws (not shown) extending vertically through the base plate into opposite extremities of the handle.
Not only does the rear portion 30 of the base 24 provide means for connecting the handle mechanism 22- to the base, but it also includes upwardly extending ears 51 at the sides thereof for receiving pivots 54, to pivotally connect the blade holder 26 to the base for vertical swinging movement relative thereto. In this regard, the illustrated form of the blade holder 26 includes vertically extending flanges 56 along the sides of the ears 51 and the pivots 54 extend horizontally through the flanges and the ears to pivotally connect the blade holder to the base 24.
A support plate 58 is connected between the flanges 56 and is downwardly and outwardly inclined toward the front of the base. The support plate 58 is designed to canry a pair of carpet cutting blades 60 and 61 and to support the blades at an acute angle relative to and over the front of the base 24. The support plate 58 is also vertically adjustable to control the height of the blades 60 and 61 above the base 24 and the acute angle at which the cutting one of the blades severs the carpet 12 to insure that the resulting carpet edge is a squared edge which will butt snugly against the wall 16.
To provide the desired vertical adjustability of the support plate 58 and hence of the blades 60 and 61, the blade carrying attachment 20 includes the adjustment device 28 for selectively setting and locking the support plate in various vertical positions above the base 24 with the blade holder 26 swinging vertically on the pivots 54. By way of illustration only, the adjustment device 28 is represented as comprising a threaded stud 64, a coil spring 66 and a wingnut 68 (see FIG. 3). The stud 64 is fixed to and extends vertically from the middle of the front portion 32 of the base 24 and through an opening 70 in the support plate 58. The coil spring 66 is around the threaded stud 64 on top of the base 24 and bears upwardly on the under surface of an upwardly struck shoulder 72 formed in the support plate and including the opening 70. The wingnut 68 is threadedly engaged on the upper end of the threaded stud 64 and bears on the top surface of the shoulder 72, around the opening 70.
Thus arranged, the spring 66 normally urges the blade holder 26 upwardly away from the base 24 tending to swing the blade holder in a clockwise direction on the pivots 54 as viewed in FIG. 1. Such swinging of the blade holder 25, however, is resisted by the wingnut 66 on the stud 64 and rotation of the wingnut in one direction, rotates the blade holder clockwise on the pivots 54 while rotation thereof in the reverse direction permits counterclockwise rotation of the blade holder on its pivots by the spring 66. Such vertical adjustment of the blade holder 26 by swinging on its pivots 54 controls the height and slightly varies the angle of the blades 60 and 61 relative to the base and hence the angle at which the carpet edge portion 14 is severed. By proper adjustment of the wingnut 68, the cutting angle may be set to fully compensate for the previously referred to contraction and expansion of the cushion back carpeting 12, which normally occurs after a severance of the edge portion 14 therefrom, thereby producing a squared carpet edge.
With regard to such contraction and expansion and the compensation therefor and as illustrated most clearly in FIG. 1, when the carpeting 12 is folded upwardly against the wall 16, the nap 20 and upper surface of the backing 18 are compressed along and adjacent to the fold of the carpet while the lower portion of the backing is extended. This means that when the carpet edge portion 14 is severed, the nap 20 and upper surface of the backing 18 will expand laterally and the lower portion of the backing will contract. Therefore, to produce the desired squared carpet edge, the cutting one of the blades 60 and 61 should sever the carpet along an acute angle relative to the horizontal base 24 and floor 39. In particular, by cutting the edge portion 14 at the proper angle, the nap 20 and backing 18 will expand and contract to form a substantially squared edge which will butt snugly against the wall 16.
The foregoing vertical adjustment feature of the blade holder 26 also insures a resulting squared carpet edge upon severance of the edge portions of carpets of different types of cushion backing and different types of nap. In particular, irrespective of the expansion and contraction characteristics of the nap and backing, the blade holder 26 may be vertically adjusted to cause the blades to cut the edge portion of the carpet at an angle which will produce a substantially squared carpet edge. Furthermore, by vertical adjustment of the blade holder 26, such various types of cushion back carpeting may be cut at different heights above the floor to insure that the resulting carpet edge will butt against the adjacent wall.
It is also an important feature of the attachment 20 that it will efiiciently trim edge portions of cushion back carpeting of various thicknesses. This is accomplished by the inclusion of a hand adjustable blade support device 74. The blade support device 74 also allows the blade holder 26 to support different types of carpet cutting blades of various shapes such as a slotted blade (the form illustrated) and the so-called Universal trimmer blade.
Generally speaking, the blade support device 74 sup ports the blades 60 and 61 on top of the support plate 58 and permits manual adjustment of the projection of the blades beyond the front of the base 24 in accordance with the thickness of the carpeting being severed by the tool 10. In this regard, it is of course desired that the cutting one of the blades 60 and 61 extend completely through the carpeting without engaging and hence marring the surface of the wall 16 during severance of the carpet edge portion 14. The blade support device 74 also is designed to angularly orient the cutting edges of the blades 60 and 61 with respect to the angular plane of the blades so that during cutting operation, the blade cutting edge exerts a shearing action on the carpet thereby reducing the chances of tearing or otherwise marring the carpet.
To accomplish the foregoing, the blade support device 74 comprises forwardly diverging channels 76 and 78, one on each side of the shoulder 72 on the support plate 58, a cover plate 80 and a pair of hand adjustable set screws 82 and 84.
As illustrated most clearly in FIGS. 2 and 4, the
channels 76 and 78 are formed by two pairs of upwardly struck parallel ridges 86 and 87 extending upwardly and rearwardly along the upper surface of the support plate 58. The blades 60 and 61 are adapted to slide along the channels 76 and 78 up and down the face of the support plate 58.
The cover plate 80 is generally V-shaped and dimensioned to fit over the top of the support plate 58 around the shoulder 72 with left and right portions extending over the channels 76 and 78, respectively. Elongated slots 88 are included in the cover plate 80 over central portions of the channels 76 and 78 to permit hand contact with the blades 60 and 61 whereby the blades may be moved longitudinally within the channels when the cover plate is not clamped firmly to the support plate.
In this regard, the cover plate 80 includes a pair of cars 90 extending from front edge portions thereof on opposite sides of the shoulder 72. The ears 90 extend into slots 92 in upwardly extending flanges 94 from the support plate 5'8. The cover plate 80 is adapted to bear on top surfaces of the support plate 58 adjacent the ridges 86 (and on the blades 60 and 61 when in the channels) with the ears bearing on the tops of the slots 92. From the channels 76 and 78, the cover plate 80 is effectively cantilevered over the top surface of the support plate 58 (see FIG. 4) to receive the set screws 82 and 84 at upper left and right portions adjacent the ends of the support plate the set screws passing through openings 96 in the cover plate and screwing into threaded holes 98 in the support plate. When the set screws are not tightened down on the cover plate 80, the blades 60 and 61 may be slid by hand up and down the inclined channels 76 and 78. However, upon a tightening of the said screws, the cover plate 80 is forced tightly onto the top of the blades 60 and 61 with the ears hearing tightly on the tops of the slots 92 in the flanges 94. The blades 60 are thus clamped in position within the channels.
When the tool 10 is not in use, the blades 60 and 61 may be completely recessed in the channels 76 and 78 and under the cover plate 80 with a generally triangular ridge 100 immediately to the rear of the shoulder 72 acting as a stop preventing the blades from riding upwardly out of the channels. When it is desired to utilize the tool 10, the set screws 82 and 84 are loosened to unlock the blades from the blade holder 26. One or the other of the blades may then be moved by hand to project from its associated channel beyond the front edge of the base 24 an amount controlled by the thickness of the cushion back carpeting to be severed by the tool. If the tool is to sever the edge portion 14 of the carpet 12 by rearward pushing movement, when viewed in FIG. 1, the blade 60 is extended while the blade 61 is maintained recessed within its channel 78. The converse is true if the carpet edge portion is to be severed by forward pulling movement of the tool. The set screws are then again tightened to lock the blades in their respective positions thereby readying the tool for use in severing the carpet edge portion 14.
By way of summary and review, when a carpet installer desires to trim the edge portion 14 of the cushion back carpeting 12 and to create a squared carpet edge which will abut firmly against the wall 16, he first loosens the set screws 82 and 84 and selectively adjusts the blade 60 to the desired projection. That is, he extends the blade 60 such that its projection beyond the front of the base 24 and guide 38 is slightly greater than the thickness of the carpeting. The installer then retightens the set screws to lock the blades in place, the blade 61 remaining recessed in its channel 78 under the cover plate 80.
Next, by turning the wingnut 68, the installer adjusts the height of the blade 60 above the base 24 such that the blade will sever the carpet edge portion 14 at an acute angle and such that the new edge portion of the carpeting 12 will expand and contract and form a substantially squared carpet edge for butting snugly against the wall 16.
Having thus pre-adjusted the tool 10, the installer grasps the handle 52 and presses the tool downwardly on the top surface of the carpet 12 and the guide 38 tightly against the edge portion 14. He then pushes the tool rearward, when viewed in FIG. 1, along the edge portion 14 with the guide making a two-point contact with the carpeting forward of cutting blade 60. This insures that the tool closely follows the contour and any irregularities in the wall 16 and that the resulting edge will closely follow the surface of the wall adjacent the floor 39.
As the tool 10 is pushed rearward, the downwardly inclined angularly oriented cutting edge of the blade 60 shears the cushion back carpeting leaving a smooth, clean carpet edge for abutting against the wall 16. The cutting operation is repeated for each edge of the carpeting 12 to complete the installation of the wall-to-wall carpeting.
In view of the foregoing, it is appreciated that the present invention provides an improved device for trimming the edge of cushion back carpeting which produces squared carpet edges adapted to fit snugly against adjacent walls and which is adjustable to produce such squared edges for cushion back carpeting of different thickness and different backing types.
While a particular form of carpet trimmer has been described in some detail herein, changes and modifications may be made in the illustrated form without departing from the spirit of the invention. It is therefore intended that the present invention be limited in scope only by the terms of the following claims.
I claim: 1. In a cutting tool, the combination of: base means having front and rear portions; blade holder means having front and rear portions, including means for supporting a cutting blade at an angle to the lower surface of said base means and projecting over said front portion of said base means;
pivot means for pivotally supporting said rear portion of said base holder means on said rear portion of said base means for rotational movement of said blade holder means with respect to said base means; and
adjustment means between said base means and said blade holder means for adjusting the rotational position of said blade holder means relative to said base means including spring means between said base means and said blade holder means for continuously urging said blade holder means away from said base means and hand turnable means connected to said base means and bearing on said blade holder means for adjusting the vertical height of said blade holder means relative to said base means by a turning thereof.
2. The combination of claim 1 wherein said combination further comprises a threaded stud extending vertically from said base means and through an opening in said blade holder means and said hand turnable means includes a nut on said stud and bearing on said blade holder means to adjust the vertical height of said blade holder means on said stud by a turning thereof.
3. The combination of claim 1 wherein said front portion of blade holder means is downwardly and forwardly inclined and wherein said combination further includes support means for connecting a cutting blade to said front portion of said blade holder means to extend at an acute angle relative to said base means.
4. The combination of claim 3 wherein said support means comprises:
a channel on said inclined front portion of said blade holder means for slidably receiving said blade; a cover plate extending over said channel; and hand operable means for pressing said cover plate onto said blade to lock said blade in said channel. 5. The combination of claim 3 wherein: said tool includes first and second blades; and said support means connects said first and second blades to said inclined front portion of said blade holder means and at an acute angle relative to said base means and includes first and second forwardly extending and outwardly diverging channels on said front portion of said blade holder means for slidably receiving said first and second blades respectively,
a cover plate cantilevered from said front portion of said blade holder means over said channels and said blades,
and screw means through said cover plate and into upper rear portions of said front portion adjacent ends thereof for pressing said cover plate onto said blades in said channels to releasably lock said blades to said blade holder means.
References Cited UNITED STATES PATENTS 2,065,761 12/1936 Smith 30-293 2,037,133 7/1937 Fulton 30-239 2,772,474 12/1956 Hill et al. 20-293 2,306,233 9/1957 Brennan 30-294 3,337,955 3/1967 Poletajev 30-294 JAMES L. JONES, 111., Primary Examiner.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION August 6, 1968 Patent No. 3,395,453
Earle F. Prater It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:
Column 7, line 15, "base" should read blade Signed and sealed this 3rd day of February 1970.
WILLIAM E. SCHUYLER, JR.
Edward M. Fletcher, Jr.
Commissioner of Patents Attesting Officer