WO2000045013A1

WO2000045013A1 - Carpet removal device

Info

Publication number: WO2000045013A1
Application number: PCT/SE2000/000156
Authority: WO
Inventors: Sture Berg
Original assignee: Hamatic Ab
Priority date: 1999-01-26
Filing date: 2000-01-26
Publication date: 2000-08-03
Also published as: AU2470200A; SE9900245L; SE513439C2; SE9900245D0

Abstract

The invention relates to a stripper head (10) for a floor removal machine, comprising a frame (20), a reciprocating arm (50) mounted in the frame having a front and a rear portion, which front portion is provided with cutter means (506) with an elongate, transversal cutting edge (506b) which is located in a first plane (i), carrying means carrying the reciprocating arm (50) in the frame (20) for motion in all directions relative to the frame in a second plane (ii) which is substantially parallel relative to the first plane (i), an eccentric shaft (30) driving substantially transversally relative to the second plane (ii), having means for connection to driving means, and which is arranged in the rear portion of the reciprocating arm (50) for providing it with an orbital motion in the second plane. The invention is characterised in that the major part of the mass of the reciprocating arm (50) is located in front of the eccentric shaft (30), and that the carrying means comprise a plurality of resilient damping members (40) which are inserted between the frame (20) and the reciprocating arm (50) in front of, and behind the eccentric shaft (30) and on both sides of a plane (A) which extends through the eccentric shaft (30) and transversally relative to the cutting edge, and is transversal in relation to the second plane.

Description

CARPET REMOVAL DEVICE

Technical background

The present invention relates to an eccentrically driven stripper head for a machine for removing or stripping floor coverings, and a machine for removing or stripping floor coverings comprising such a stripper head, and more specifically the present invention relates to a stripper head which allows for efficient and rapid removal of the floor material by means of an elliptic movement of the floor stripping means which is driven at a high speed of rotation.

Prior art

It is since long known to use powered devices for removing floor coverings, and especially floor coverings that have been fixed by means of adhesives. Such devices use the principle of applying an eccentric motion to the floor stripper means, which is mounted on a reciprocating arm in order to make the floor stripping means move in an essentially reciprocating way, for stripping the floor material from the underlying floor.

However, such floor stripping machines according to prior art suffer from a number of drawbacks. Firstly, they have a relatively low stripping efficiency compared to what is desirable, which in part is due to the problems the use of conventional floor stripping machines present to the operator. The problems of conventional floor stripping machines are mainly related to the heavy vibrations that are produced when they are operated. For some machine types, the result of these vibrations is that the machine moves sideways which is difficult to control for the operator, since the operator has to counterbalance the sideways movements to be able to strip the floor material with some degree of efficiency.

Further, the heavy vibrations of the machine also result in a relatively non-uniform stripping of the floor material, since it is difficult to make the floor stripping means follow the surface of the floor. Thus, apart from a heavy working environment for the operator, the vibrations of conventional machines also result in limited possibilities of stripping the floor material with the desired speed. From US-4 162 809, a floor stripper device is known, comprising stripping means mounted on a mounting and drive arrangement, which in turn is connected to an eccentric device driven by an electric motor. This provides the stripping means with an elliptic motion. The translatory motion of the driving means is controlled adjacent to the stripping means so that this motion will be produced with an angle in relation to the frame of the machine, thus limiting its transversal motion to some extent. This decreases the centrifugal action of the stripping means in order to reduce the vibrations of the machine. This device is still, however, largely without damping action, and it is due to the relatively unflexible mounting of the stripper difficult to make it follow the underlying surface. Further, the relatively limited damping or spring action means that it is difficult to drive the machine at high rotational speeds, e.g. approximately 6000 rpm and higher.

Thus, there is a need for a floor stripping machine which is capable of eliminating the above mentioned drawbacks of heavy vibrations and low stripping capacity.

Brief description of the invention

The present invention aims at solving the above mentioned problems by means of a stripper head for a floor removal machine as defined in claim 1 , and a floor removal machine comprising such a stripper head, as defined in claim 6.

Short description of the drawings

Below, a preferred embodiment of the invention will be described in closer detail, reference being made to the appended drawings, in which:

fig. 1 is an elevational view from above, partly in section, of an eccentrically driven stripper head for a floor removal device according to the present invention;

fig. 2 is a cross section, along the line II-II, of a bearing assembly according to the present invention, and

fig. 3 is a side elevational view of a floor removal machine equipped with a stripper head according to the present invention. Description of a preferred embodiment

Fig. 1 shows an elevational view from above, partly in section, of a preferred embodiment of an eccentrically driven stripper head for a floor removal device according to the present invention, generally designated by the reference numeral 10. In the embodiment the stripper head is comprised of a frame or housing 20 having a rectangular cross section and an upper wall 202, a lower wall 204, which two walls can be seen in fig. 2, and two side walls 206 and 208. In the embodiment shown, the housing 20 has an integral design, e.g. welded from separate parts, which is preferable from a strength point of view, but it is, however, conceivable to provide a housing consisting of two halves joined by means of suitable fastening means.

In the upper and lower wall 202 and 204 respectively there are provided shaft holes, one upper and one lower 202a and 204a respectively, for receiving an eccentric shaft or stripper shaft 30. In the upper wall 202 and in the lower wall 204 there are provided mounting holes for damping members 40. Said mounting holes are provided symmetrically relative to the shaft holes 202a and 204a, the two rear holes located on the side which is opposite to the side of the cutter means 506 according to fig. 1, being arranged on a line which is transversal to a longitudinal symmetry line A dividing the stripper house and a reciprocating arm 50 in two portions which are mirror images of each other, and the two forward holes located on the same side as the cutter means 506 in fig. 1 , are arranged on a line which is transversal relative to the symmetry line A which coincides with the section plane II-II, said two transversal hole lines being located on the same distance behind and in front of the shaft holes 202a and 204a respectively.

As an alternative, the hole pattern of the mounting holes may be modified so that the forward and the rear holes respectively are arranged on different distances from the shaft holes 202a and 204a. The holes are, however, preferably arranged symmetrically relative to the symmetry line A, for reasons stated below, even though other alternatives of course are conceivable.

The stripper shaft 30 is an eccentric shaft having an eccentrically arranged driving portion 302, which is more clearly shown in fig. 2, which is located between the upper and the lower wall, and on which portion a reciprocating arm 50 has been mounted. The upper end of the stripper shaft 30 is received in bearing means 306 provided in the shaft hole 202a in the upper wall 202 of the housing 20. The stripper shaft 30 extends through bearing means 304 provided in the shaft hole 204a in the lower wall 204 of the housing 20. The stripper shaft 30 terminates, below the bearing means 304, in suitable means for mounting of driving means, in a preferred embodiment comprised of a belt pulley 60. Said means may be comprised of an external threading, onto which e.g. a belt pulley 60 having a corresponding internal threading may be screwed and fixed in a suitable way.

The bearing arrangement in the housing 20 is preferably comprised of bearings of a suitable dimension, e.g. conventional deep groove ball bearings.

In figure there is further shown a reciprocating arm 50, which is driven in an orbital path of motion by the eccentrically driving stripper shaft 30. The reciprocating arm 50 has a forward end 502 having a suitable mounting arrangement, e.g. screw holes, for mounting, by means of screws 504, of removal means, preferably stripping means 506 having a cutting edge 506b of the type shown in the figure. The forward end 502 of the reciprocating arm 50 forms an angle α relative to the underlying surface which amounts to approximately 45°, but which may be varied, e.g. by means of spacers (not shown) of different thicknesses and angles. The reciprocating arm 50 has a shaft hole through which the stripper shaft 30 extends. The reciprocating arm 50 and the stripper shaft 30 are interconnected by means of a bearing arrangement 70 which is described in closer detail below. Further, the reciprocating arm has mounting arrangements on the upper and lower sides, preferably screw holes, for the resilient damping members 40, arranged according to the same symmetrical pattern as the corresponding mounting holes in the housing 20.

The cutting edge 506b of the stripping means 506 is located in a first plane, i, and the reciprocating arm 50 onto which the cutter means is mounted, is brought into motion in a second plane, ii, which is substantially parallel relative to the first plane i, by the eccentrically driving stripper shaft 30, which drives in a plane which is substantially transversal relative to the second plane ii. In a preferred embodiment, the resilient damping members 40 are comprised of elongate rubber members, having a suitable cross section. Said members have mounting holes in both ends, in which holes internal threads have been arranged for receiving and holding a mounting screw 202b-e and 204b-e which are introduced through the respective mounting hole 202b-e and 204b-e. In this way, holding and resilient damping of the reciprocating arm is obtained in all directions, i.e. in the directions forward, rearward and to the sides, as well as upwards and downwards and all possible combinations thereof. In this way the cutting edge 506b of the stripping means is allowed to move along the underlying surface in a floating manner, which is very advantageous in terms of the operation of the machine.

Preferably, the resilient damping members that are mounted in front of the shaft are made from a softer rubber material than the resilient damping members that are mounted behind the shaft. In a preferred embodiment the forward rubber members have a hardness of approximately 45 Shore A, while the rearward rubber members have a hardness of 55 Shore A.

Fig. 2 shows a cross sectional view of the reciprocating arm bearing arrangement 70 according to the present invention. According to prior art, traditional bearing arrangements for this application have been comprised of a deep groove ball bearing or a similar arrangement, intended to receive the radial forces that are produced when the stripper shaft drives the reciprocating arm mounted thereon by means of the bearing arrangement. Such an arrangement suffer from major drawbacks, especially in terms of life-span, when the rotational speed of the stripper shaft is increased in accordance with the present invention. An increase in rotational speed means increased requirements concerning the bearing arrangement of the reciprocating arm, since the magnitude of the radial forces increase in a substantial way when the rotational speed is increased.

In accordance with the present invention there is provided an improved bearing arrangement that is able to withstand the increased loads of a higher rotational speed, preferably in the range of at least 9000 rpm. This bearing arrangement is comprised of an outer spherical bearing 702 of relatively large dimension, comprising an internal bearing ring and an inner spherical bearing ring, which spherical bearing is mounted in the shaft hole 508 of the reciprocating arm 50. In the outer spherical bearing ring 702 there has been provided bearing seats for upper and lower internal bearings 704 and 706 respectively. In a preferred embodiment these bearings are deep groove ball bearings which are in turn fitted onto the eccentric driving portion 302 of the stripper shaft.

In this way a bearing arrangement is obtained which has a good ability to withstand and absorb the large forces that are produced when the stripper shaft 30 is driven with a rotational speed of approximately 9000 rpm and with high load, since the bearing arrangement for the reciprocating arm according to the present invention provides a large bearing surface in comparison with prior art, which means lower bearing pressure and thus a lower working temperature of the bearing arrangement. In the end this has an influence on problems concerning the limited life-span, which are alleviated, which is a prerequisite for an acceptable function without stops during the use of a floor removal machine equipped with a stripper head according to the present invention, with a high stripping speed. Further the bearing arrangement, in co-operation with the resilient damping means, allow the cutting edge of the stripping means, to float along with the underlying surface, which contributes to its smooth function and stripping efficiency.

The present invention also relates to a floor removal machine 80 equipped with a stripper head in accordance with the preceding paragraphs, said machine being shown in figure 3. The machine 80 is comprised of a chassis 82, a pair of wheels 822, of which only one is visible in the figure, is mounted on a rear part of the chassis, and a stand 924 which is resiliently suspended by means of rubber members or other suitable means, and which is provided, on the one of its ends which is not mounted to the machine, with handle means 924a by means of which the operator drives the machine forward. Further, the machine 80 has a driving unit comprising a conventional electric motor 92, and a transmission 94. The electric motor 92 is supplied with electric power via a control panel 922, by means of which the motor function is controlled. Normally, only the positions on and off are used, but it is however possible to provide means for controlling the motor power. The motor 92 is coupled to the drive shaft 30 by means of a transmission 94, which in a preferred embodiment comprises a gear mechanism. The rotational speed of the shaft connected to the motor is transformed in the gear mechanism to a higher rotational speed, in a preferred embodiment approximately 9000 rpm. This rotational speed is delivered on an output shaft on which a belt pulley 942 is provided. This belt pulley 942 drives a driving belt 944, which in turn drives a belt pulley 60 mounted on the stripper shaft 30.

Thanks to the high rotational speed by means of which the stripper shaft, and thus the reciprocating arm and the stripping means are driven, an efficient stripping of the floor material to be removed is achieved, and by means of the efficient damping and the controlled motion of the reciprocating arm, a smooth function free from vibrations is achieved, without the above cited tendencies of conventional machines to move sideways, and thus the machine is very easy to operate for the operator.

If the operator still, however, should desire help in moving the machine 80 forward, there is provided, in a preferred embodiment of the floor removal machine 80 according to the present invention, driving means which can be enabled and disabled. The gear mechanism 94 has a second output shaft which delivers a much lower rotational speed than the output speed of the motor, preferably around 100 rpm. In the preferred embodiment a belt pulley 946 or corresponding means is mounted on this second output shaft. This belt pulley 946 drives a belt 948 which is led round a belt tensioning device 950, and subsequently round a drive surface on one of the wheels 822 of the machine 80. In normal position where the belt 948 is not tensioned, it does not act on the wheel 822 of the machine 80, but when tensioned by means of the belt tensioning device 950 it will drive one or both the wheels 822 of the machine, thus driving the machine 80 forward. When the operator desires help in driving the machine 80 forward he will thus only have to actuate the belt tensioning device 950 actuator means 952, thereby enabling the drive of the machine 80 according to the above.

Claims

1. Stripper head (10) for a floor removal machine, comprising: a frame (20); a reciprocating arm (50) mounted in the frame, having a front and a rear portion, which front portion is provided with stripping means (506) with an elongate, transversal cutting edge (506b) which is located in a first plane (i); carrying means carrying the reciprocating arm (50) in the frame (20) for motion in all directions relative to the frame in a second plane (ii) which is substantially parallel relative to the first plane (i); an eccentric shaft (30) driving substantially transversally relative to the second plane (ii), having means for connection to driving means, and which is arranged in the rear portion of the reciprocating arm (50) for providing it with an orbital motion in the second plane; characterised in that the major part of the mass of the reciprocating arm (50) is located in front of the eccentric shaft (30), and that the carrying means comprise a plurality of resilient damping members (40) which are inserted between the frame (20) and the reciprocating arm (50) in front of, and behind the eccentric shaft (30) and on both sides of a plane (A) which runs through the eccentric shaft (30) and transversally relative to the cutting edge, and is transversal in relation to the second plane.

2. Stripper head according to claim 1, characterised in that the resilient damping members (40) are rubber members having different hardness, harder rubber members being provided behind the eccentric shaft (30) on the upper and the lower side of the reciprocating arm (50) respectively, and softer rubber members being provided in front of the eccentric shaft (30) on the upper and the lower side of the reciprocating arm (50).

3. Stripper head according to claim 1, characterised in that the hard rubber members have a hardness of 55 Shore A and more, and in that the soft rubber members have a hardness of 45 Shore A and less.

4. Stripper head according to any of the preceding claims, characterised in that the bearing arrangement between the reciprocating arm and the stripper shaft (30) comprises a first external bearing (702) of a spherical type having a relatively large diameter and width, and two internal bearings, an upper (704) and a lower (702) bearing in the form of ball bearings arranged inside the external bearing (702) in bearing seats provided therein.

5. Stripper head according to any of the preceding claims, characterised in that the angle (α) which is formed by the front portion of the reciprocating arm and the horisontal when the stripper shaft extends vertically, is approximately 45°.

6. Floor removal device (80) comprising a chassis (82), a pair of wheels (822) mounted on a first end of the chassis, handles (924a) arranged on a damped stand (924) which is mounted on the upper side of the machine at said first end, a motor drive (92) for driving the eccentric shaft (30), and means for actuating the motor, characterised in that the machine comprises a stripper head (10) according to any of the claims 1 to 5, which stripper head (10) is mounted at the forward, second end of the machine, fixed to the chassis (82) and driven by said motor drive (92).

7. Floor removal machine according to claim 6, characterised in that the motor drive (92) is connected to a transmission comprising a gear mechanism (94), the output shaft of which drives the eccentric shaft (30) via belt drive means (942, 944, 60).

8. Floor removal machine according to claim 7, characterised in that the transmission delivers a rotational speed that exceeds 9000 rpm.

9. Floor removal machine according to claim 7 or 8, characterised in that the transmission has a second output shaft which delivers a low rotational speed, and that drives at least one of the wheels (822) of the floor removal machine (80) via belt drive means (946, 948, 950), said belt drive means being enablable by means of a belt tensioning device (950) provided for this purpose.