Abstract:
In a cutting device, which is more particularly used for cutting laid floor coverings, which are preferably fixed flat to the substrate and having a chassis, provided with support means for support on the floor covering, in which the chassis carries at least one cutting tool, which can be transferred into a working position and where the cutting tool is in cutting engagement with the floor covering, the cutting tool is rigidly coupled to the bearing surfaces of the support means in the working position.  
     As a result, during the cutting process, the inclination or depth of cut of the cutting tool undergoes no modification and an optimum, uniform cutting can be carried out.

Description:
FIELD OF APPLICATION AND PRIOR ART  
         [0001]    The invention relates to a cutting device for making cuts in floor coverings according to the preamble of claim  1 .  
           [0002]    On laying or removing floor coverings, such as carpets, parquet floors, etc., room fitters, floor covering layers, etc. have to perform a number of operating steps. When removing floor coverings, e.g. carpets, which are bonded to the substrate, the covering to be removed is generally cut into webs or lengths and is then removed. The most widely used method is for the fitter or layer to kneel on the floor covering and cut individual webs using a knife. It is necessary to tediously manually draw off the floor covering or to remove it with a winding device, in which a winding mandrel winds up the individual floor covering webs. In order to save the room fitter or floor covering layer the tedious cutting work carried out on the knees and which gives rise to back problems, a number of different tools have been developed. It is e.g. known to fix the knife to a long holding bar, so that the fitter can cut the floor covering from the standing position.  
           [0003]    A further development of this holding bar knife is described in DE 299 06 938 U1, where a cutting knife is retained in a knife holder. The knife holder is connected to a handle. Rolls are located on either side of the knife, whose cutting plane is perpendicular to the floor covering, in order to move the entire device over the floor covering. The cutting knife is positioned upstream of the roll in the cutting direction. During the cutting process the floor covering is cut by a type of sliding cut.  
           [0004]    U.S. Pat. No. 5,485,676, which provides the basis for the preamble, discloses the clamping retention on a chassis of a cutting tool. The chassis rests on the ground by means of four bearing surfaces (wheels). In order that the cutting tool can be engaged with the substrate to be cut, the chassis must be so deformed by vertical force introduction that the cutting tool blade is brought from the non-engagement position into the working position.  
           [0005]    As in the previously described constructions, the disadvantage of this construction is that there is no fixed position between the cutting tool and the material to be cut.  
         PROBLEM AND SOLUTION  
         [0006]    The problem of the invention is to provide a cutting device which, compared with the prior art, offers improved handling possibilities, together with improved cutting quality and precision.  
           [0007]    This problem is solved by a cutting tool according to the invention.  
           [0008]    The cutting tool according to the invention is rigidly coupled to bearing surfaces of the support means in the working position.  
           [0009]    The term cutting tool in the sense of the present application means knives, e.g. carpet knives or the like. However, it is also possible to use rotating cutting tools, which roll or are separately driven during the cutting process, e.g. cutting disks, etc. The support means can be constituted by wheels, runners or other contact surfaces between the chassis and the floor covering. The cutting tool is in cutting engagement with the floor covering in the working position. If it is moved in its working position it leaves behind a cut in the floor covering. The term floor covering covers all coverings which can be laid flat on a substrate, e.g. carpets, parquet flooring, PVC, roofing felt, insulating mats, etc.  
           [0010]    In the case of the holding device described in DE 299 06 93 8 U1, the depth of cut and inclination of the cutting knife with respect to the floor covering can be modified during the cutting process, which leads to irregular cuts. It can even arise that the knife becomes jammed in the floor covering, if the handle is e.g. too strongly adjusted. If it is wished to prevent this, throughout the cutting process the operator would have to keep the handle under a predefined angle relative to the floor covering, which is very difficult to achieve.  
           [0011]    This problem does not arise with the cutting device according to the invention. By the bearing surfaces of the support means the cutting tool is fixed in such a way that during the cutting process it is impossible for it to deviate from its preset position relative to the floor covering. The depth of cut and inclination of the cutting tool consequently remain the same throughout the operation, which ensures an optimum, uniform cut.  
           [0012]    The cutting tool can have a tool body and a cutting means. In the case of a carpet knife they would be constituted by the shaft or shank and the blade. Preferably the complete cutting tool in the form of tool body and cutting means is removable from the cutting device, i.e. it can be rapidly disengaged and reengaged. This is particularly advantageous if a used or worn blade is to be replaced by a new one. However, it must be borne in mind that as a result of the stable retention of the blade relative to the cutting surface, there can possibly be an abrasion of the blade material on a rough surface located below the material to be cut. This can make necessary a resetting of the sinking in depth of the blade, but as a result of abrasion there is always a sharp cutting edge on the lower extremity of the blade.  
           [0013]    In the working position, the cutting means preferably projects through an opening in the chassis in a downwards direction towards the floor covering. The opening can have any conceivable geometry and is preferably a narrow slot, whose width is somewhat greater than that of the cutting means. Thus, the cutting means can at least be laterally guided and is secured against tilting in said direction. The opening is preferably located between two bearing surfaces of the support means.  
           [0014]    To keep the free length of the cutting means below the chassis as small as possible, the cutting means preferably projects through the underside of the chassis adjacent to a bearing surface of the support means. The tool body can be placed in fixed manner above the chassis.  
           [0015]    Preferably two support means are in each case provided with a bearing surface. The support means can firstly be constituted by a base portion of the chassis and secondly by wheels which are connected to the chassis. The two bearing surfaces of the support means and the cutting tool can form a type of three-point ground contact. Preferably the base portion of the chassis is inclined to the floor covering, e.g. under an angle of 5 to 10 φ. It can support on the floor covering the rear edge of the base portion in the working direction, whereas the remainder of the base portion rests on the wheels connected to the chassis and has no contact with the floor covering. Thus, in the working direction there is a wedge-shaped gap between the base portion and the floor covering. The cutting tool is preferably located between the two bearing surfaces and is in contact with the floor covering in the working position. Thus, during the cutting process, the cutting device is in contact therewith on three axes oriented parallel to the floor covering, namely on the axis through the trailing edge of the base portion, on the axis between the contact point between the cutting tool and the floor covering and on the axis through the bearing point of the wheels. Preferably the cutting tool is placed between the two axes of the support means in such a way that the force introduction point for the operator to introduce force onto the cutting device is also between the two bearing surfaces of the support means.  
           [0016]    According to a further development it is possible to adjust the cutting angle which is of an optimum nature relative to the cutting means geometry. This is preferably continuously adjustable in the angular range 30 to 45 φ. The cutting tool is preferably pivotably mounted on the chassis. If e.g. a carpet knife is used as the cutting tool, it can be pivotably mounted on the chassis using a hole or bore formed at the shaft end by means of a stop screw forming a rotation axis.  
           [0017]    In particularly preferred manner it is possible to adjust the engagement depth of the cutting means in the floor covering, so that the depth of cut of the cutting tool can be adapted to different floor covering thicknesses. Vertical adjustment could take place by sliding the cutting tool along an axis perpendicular to the floor covering. However, it can also take place jointly with an inclination setting, in that the cutting tool is pivoted-towards the floor covering. The cutting tool can e.g. be guided in a type of guide cage, which is connected to a setscrew. By turning the setscrew it is possible to move the guide cage towards or away from the floor covering.  
           [0018]    It is possible to provide on the cutting device a holding bar for operating, particularly sliding said cutting device. Preferably a position of the cutting tool relative to the floor covering is independent of the holding bar position. This ensures that an inclining of the holding bar during the cutting process has no effect on the inclination or depth of cut of the cutting tool. Thus, during the cutting process, the operator could move the holding bar backwards and forwards without this impairing the cut. The holding bar can be articulated to the chassis, e.g. by means of a fork, which is connected to one end of the holding bar and pivotably mounted on the chassis.  
           [0019]    According to a further development of the invention the cutting device has a marking device enabling the marking in the floor covering of the cuts made by the cutting tool. This is more particularly helpful if e.g. carpets with a high tuft are being worked, in which it would otherwise be difficult or even impossible to detect the cutting lines. The marking device is preferably a marking pen, e.g. a felt tip pen, which can be inserted in a holder on the chassis. Preferably the marking pen only presses with its force of gravity on the floor covering, so that it is subject to relatively little wear. However, it would also be possible to use other marking means, e.g. chalk, which marks in the manner of a chalking trolley for sports grounds.  
           [0020]    The cutting device can have a lever element with which the cutting means can be sunk into the floor covering at the start of the cutting process. Preferably the lever element is part of the chassis constructed as a footboard, so that the cutting means can be pressed into the floor covering by foot pressure.  
           [0021]    It is possible for the cutting device to have a spacing or distance indicator, which can have a rod, which is connected in transversely adjustable manner to the chassis. As a result the floor covering can be cut into webs of equal width without the operator having to measure the floor covering beforehand and mark the individual webs.  
           [0022]    The chassis support means can be constituted by a bearing bracket. It is preferably the rearmost support means in the working direction. Instead of being supported directly on the base plate of the chassis, the cutting device can be supported on the bearing bracket. The bearing bracket is preferably constructed in such a way that it cooperates with the cutting means, i.e. particularly the cutting knife. Preferably the cutting through of the floor covering takes place in the vicinity of the bearing bracket. The bearing bracket can comprise at least one base plate, as well as a fastening portion and a connecting portion. The fastening portion is e.g. constructed parallel to the chassis. The connecting portion projects perpendicularly downwards and to it is fixed the base plate. It is substantially horizontally oriented. In the base plate can be formed a slot, in which the cutting means can engage and is then in particular laterally supported on the base plate. The cutting means preferably does not project downwards through the slot and instead the lower end of the cutting means is in the vicinity of the slot. This inter alia ensures that on setting up the cutting device there is no damage to the substrate located below the latter. This is particularly critical if the substrate is a foil or sheet material. Separation on the bearing bracket serves to ensure that the substrate of the floor covering to be worked located below the covering material to be cut is not damaged. This is particularly advantageous if there are several superimposed floor coverings and only part of these are to be separated. Such applications e.g. arise at landfills or ponds with several superimposed sheets, where in the case of a water barrier consisting of several sheet layers only the uppermost sheet is to be cut through, whereas the sheets below it are to remain undamaged. The bearing bracket preferably has a base plate with a bevel. The bearing bracket rests on the substrate to be worked and slides on it, whilst the floor covering to be worked is conveyed over the bevel to the cutting point on the bearing bracket and is there cut through using the cutting means. The bearing bracket protects the cutting means from damage when not in use. The bearing bracket also provides protection against injury by the cutting means, because direct access to the blade is impossible. It is also possible to set down the cutting device anywhere without having to fear damage occurring to the substrate through the cutting means.  
           [0023]    These and further features can be gathered from the claims, description and drawings and the individual features, both singly and in the form of subcombinations, can be implemented in an embodiment of the invention and in other fields and can represent protectable constructions for which protection is hereby claimed. The subdivision of the application into individual sections and the subheadings in no way limit the general validity of the statements made thereunder. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    Embodiments are described in greater detail hereinafter relative to the attached drawings, wherein show:  
         [0025]    [0025]FIG. 1 A three-dimensional view of a first embodiment of the cutting device.  
         [0026]    [0026]FIG. 2 A diagrammatic side view of the first embodiment of the cutting device.  
         [0027]    [0027]FIG. 3 A larger scale side view of a detail of a second embodiment of the cutting device. 
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0028]    [0028]FIG. 1 shows a first embodiment of the cutting device  11  for cutting floor coverings  12  laid out preferably flat on the substrate. The cutting device  11  essentially comprises a chassis  13 , a cutting tool  14  fitted to the chassis and a holding bar  15  connected to the chassis  13 . One particular application is the cutting of laid, bonded fitted carpets.  
         [0029]    The chassis  13  has a U-shaped cross-section with two side portions  16 , which are parallel to one another and perpendicular to the floor covering, as well as a base portion  17  connected to the side portion  16 . The chassis  13  has support means  18 ,  19  supported on the floor covering  12 . In the described embodiment there are two support means  18 ,  19 , namely wheels, which are connected to the chassis  13  and the trailing edge of the chassis in the working direction  20  of the cutting device  11 . Thus, the base portion  17  is inclined to the floor covering  12  and is supported on its trailing edge in the working direction  20 , whereas the front part of the base portion  17  rests on the wheel axle  21 . Thus, in the movement direction  20  a wedge-shaped gap is formed between the base portion  17  and the floor covering  12 . The wedge angle is e.g. approximately 3 to 10 φ. However, it is also conceivable to have a steeper setting of the base portion  17 . The support means  18 ,  19 , i.e. the rear or trailing edge of the chassis  13  and the wheels, are in contact with the floor covering  12  at their bearing surfaces  22 ,  23 . In the case of the wheels the bearing surface  22  is limited to a narrow, approximately linear area. The bearing surface  23  of the trailing edge is also approximately linear. The size of the bearing surfaces  22 ,  23  is mainly linked with the characteristics of the floor covering  12 . In the case of working a soft floor covering, e.g. a carpet with a high tuft or a soft PVC covering, the wheels or the trailing edge can sink into the floor covering and are supported on one surface. Through the two wheels of the chassis  13  and its trailing edge a type of three-point ground contact on the floor covering  12  is created. As an extension to the trailing edge of the chassis  13  is provided an upwardly offset lever element  24  in the manner of a footboard. By pressure on the lever element  24  the cutting tool  14  can be sunk into the floor covering  12 . A marking device  26  is provided at the front end of the chassis  13  in the working direction  20 . The marking device  26  comprises a holder  27  and a marking means  28 , such as e.g. a felt tip pen, which can be inserted in the holder  27 . The marking means  28  rests under its own force of gravity on the floor covering  12 . A distance or spacing indicator  29  is fixed by a weld  30  to the rear end of the chassis  13  in the working direction  20 . The spacing indicator  29  comprises a type of chassis-side screw clip in which is held in positionally variable manner a rod  31 .  
         [0030]    In the embodiment described the cutting tool  14  is a carpet knife. It comprises a shaft or shank constructed as a tool body  32  and a blade constructed as the cutting means  33 . The shaft is pivotably mounted above the chassis  13 . For mounting purposes is provided a retaining clamp  34 , which bilaterally flanks the shaft end. A stop screw  35  traverses corresponding tapholes of the retaining clamp and a through-bore at the blade-remote end of the shaft. The stop screw  35  forms a rotation axis for the cutting tool  14  and otherwise holds it in positionally defined manner. By firmly rotating the stop screw  35  it is possible to secure the shaft against lateral tilting. In the vicinity of the transition from shaft to blade, the latter is held in a guide cage constructed as a guide device  36 . The guide device  36  is connected by two screws to the shaft  13 . The guide device  36  essentially comprises three parts, namely a base part  37 , a knurled-head screw  38  and a not shown guide cage. The knurled-head screw  38  is mounted in the base part  37  and connected to the guide cage. By turning the knurled-head screw  38  the guide cage can be moved towards or away from the floor covering  12 , which brings about the vertical adjustability of the cutting tool  14 .  
         [0031]    As can be seen in FIG. 2, the cutting means  33  constructed as a blade projects through an opening on the base portion  17  of the chassis  13  into the floor covering  12 . The angle between the cutting means  33  and the floor covering  12  is always the same during the operation and is in the range between 30 and 45 φ and is preferably approximately 35 φ and consequently corresponds to the optimum angle of cut of the blade.  
         [0032]    A holding bar  15  is provided for operating the cutting device  11 . The holding bar  15  is connected by a clip device  40  to a holding fork  41 , which is articulated to both side portions  16  and  17  of the chassis.  
         [0033]    [0033]FIG. 3 shows a second embodiment of the cutting device  11 . It differs from the first embodiment in that as the support means  19  is provided a bearing bracket  42  in place of the trailing edge  13  of the chassis. The bearing bracket  42  is detachably fixed by fixing means  46  to the underside of the chassis  13 . The fixing means can be screws, clamp or clip devices, etc.  
         [0034]    The bearing bracket essentially comprises three parts, namely a fixing portion  47 , a connecting portion  48  and a base plate  44 . By means of the fixing portion  47 , which is constructed as a flat plate parallel to the chassis  13 , using the fixing means  46  of the bearing bracket  42  detachable fixing can take place to the underside of the chassis  13 . The connecting portion  48  projects vertically downwards from the fixing portion  47 . The connecting portion  48  has on its front side located in the working direction a type of blade  49 , which during the further conveying of the floor covering strips assists in that it serves as a cutting member for the cut floor covering. Below the connecting portion  48  is located the base plate  44 . At the top the connecting portion  48  is connected to the base plate  44  and at the bottom to the fixing portion, e.g. by means of a welded joint. Additionally or alternatively a press fit of the connecting portion  48  in slots on the fixing portion  47  or base plate  44  is possible. The base plate  44  slides over the substrate of the floor covering to be worked, e.g. a further floor covering  50  or a substrate  51 . On its front side in the working direction  20 , the base plate  44  has a bevel  45 . In the vicinity of this bevel  45  or, considered in the working direction, shortly behind it, is located the cutting point  43  for the floor covering, i.e. the point at which the cutting means  33  cuts through the floor covering. The cutting means  33  is guided in a slot and in the vicinity of the latter can project into the bevel  45  of the base plate  44 . However, between the substrate, e.g. the further floor covering  50 , and the lower edge of the cutting means  33 , there is always a spacing X in order not to cause damage to the same.  
       OPERATION  
       [0035]    Firstly, by means of the spacing indicator  29 , the web width, i.e. the spacing to be maintained between two cuts is set. The screw of the screw clamp is loosened and the rod  31  is engaged with a reference point, e.g. the wall. Then the screw on the screw clamp is tightened and the spacing is preset, so that the floor covering  12  can be cut into webs of equal width. The knife is then introduced into the cutting device  11 . For this purpose the stop screw  35  on the holding clamp  34  is loosened, so that the cutting tool  4 , e.g. a carpet knife, can be slid into the cutting device  11 . The shaft of the cutting means  33  constructed as a tool body  32  is guided by the guide cage of the guide device  36 . Following the introduction of the cutting tool  14 , the stop screw  35  is tightened, so that the holding clamps  34  are drawn together and the shaft of the cutting means  33  is secured against lateral tilting. Then adjustment takes place on the cutting tool  14  to ensure the desired depth of cut. The necessary depth of cut is dependent on the thickness of the floor covering  12  to be worked. Preferably the depth of cut is set in such a way that the floor covering  12  is completely cut through. If several coverings are superimposed, the depth of cut can also be chosen in such a way that only part of the coverings is cut through, whereas coverings below the same remain undamaged. The setting of the depth of cut takes place with the guide device  36  and the guide cage. The cutting tool blade can e.g. be a trapezoidal knife or a hook blade of a carpet knife. By turning the knurled-head screw  38  the tool body  32  and consequently the blade-type cutting means  33  is guided in the direction of the floor covering  12 . When the desired depth of cut has been set, the cutting device  11  is brought into the starting position. By foot pressure on the lever element  24  the blade can be pressed into the floor covering  12 . As shown in FIG. 3, in the second embodiment of the cutting device  11  the bearing bracket  42  is brought into the starting position. Then the floor covering  12  to be worked is raised and placed on the bevel  45  of the base plate. During the cutting process the cutting device  11  is moved forwards by means of the holding bar  15 . In the working direction  30  the holding bar  15  is substantially perpendicular relative to the cutting tool  14 . Thus, in the described embodiment, the cutting tool  14  performs a dragging cut in the manner of a plough. In the working direction  20 , the cutting area of the cutting tool  14  is behind the bearing surface  22  of the wheels. Throughout the cutting process the cutting tool  14  is rigidly coupled with the beating surfaces  22 ,  23  of the support means. The inclination and depth of cut of the cutting tool  14  can not diverge from the preset position during the cutting process. A position change of the holding bar  15  also does not alter this position. This ensures a uniform cutting through of the floor covering  12 . For marking the cut performed by the cutting tool  14  a marking device  26  is provided. This enables the operator to detect the position of the already made cuts and perform the next cut with the spacing set on the spacing indicator.  
         [0036]    In the second embodiment, if the cutting device  11  is moved in the working direction  20 , the floor covering  11  to be worked is raised by the wedge-shaped bevel  49  from the substrate, e.g. a further floor covering  50  and conveyed to the cutting point  43  on the bevel  45 . At the cutting point  43  is located the cutting means  33  which cuts the floor covering  12  into strips. The cut through floor covering strips are conveyed on to the right and left of the connecting portion  47  on the base plate  44  until at the end of the latter they again drop onto the substrate. The blade  49  ensures that separation takes place of any not completely cut through floor covering material.  
         [0037]    Following the cutting process the cutting tool can be set back or reset, so that e.g. the blade is located in or above the opening on the base portion  17 . This ensures a secured non-use position in which the cutting device can be safely transported.