Abstract:
A pipe cutting device is provided. The device is based on a cutting member having a body with a radial pipe entry slot for receiving a pipe at a required cutting position along its length and having a cutting assembly for cutting the pipe upon rotation of the cutting member around the pipe. The device comprises a drive member having a drive means for causing the cutting member to rotate. The drive means is adapted to provide continuous drive to the cutting member body. Drive forces are not temporarily lost as the pipe entry slot rotates relative to a drive means.

Description:
PRIOR APPLICATIONS  
       [0001]     The present reference claims priority from United Kingdom Patent No. GB0423469.6 filed Oct. 22, 2004, the entire contents of which are herein incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to a device for cutting pipes, tubing and the like. More specifically, the present invention relates to a powered or powerable pipe cutting device for the automated cutting of pipes, tubing and the like.  
         [0004]     2. Description of the Related Art  
         [0005]     It is known, for example from U.S. Pat. No. 4,831,732 and GB2288353, to provide a manual pipe cutting device comprising a cylindrical body with a longitudinal radial entry slot into which a pipe can be introduced. As the cylindrical body is manually turned around the pipe a cutting wheel is biased into contact with the pipe and progressively cuts into the pipe.  
         [0006]     The advantage of a body with a radial slot is that it allows the pipe cutter to be introduced at any point along the length of the pipe as opposed to configurations without a slot, such as that shown in EP 0 483 076, in which a pipe must be inserted longitudinally through a cutting device. The presence of the radial slot allows, for example, the pipe cutter to be introduced to a pipe which is already connected at both ends and therefore does not have a free end over which the pipe cutter can be passed, and to be easily introduced to long pipes.  
         [0007]     Referring now to  FIGS. 1 and 2  there is shown a conventional pipe cutting member generally indicated  1 . The cutting member  1  comprises a cylindrical body  2  having a radial slot  3  extending longitudinally there through. The slot  3  is defined by a slot wall  4  comprising two parallel side walls  4   a ,  4   b  and a U-shape bight  4   c  joining the side walls  4   a ,  4   b.    
         [0008]     The generally C-shape configuration of the body  2  allows the cutting member  1  to be placed around a cylindrical pipe  5  at a desired cutting point, with the pipe  5  resting in the semi-circular recess provided by the bight  4   c . The cutting member  1  includes cutting means (not shown) operable such that when the body  2  is rotated about the longitudinal axis of the pipe  5  a cutting blade or the like is biased into contact with the pipe  5  and progressively produces a cut transverse its length. For the sake of simplicity and brevity the exact details of the cutting means are not described herein are asserted to be known to those of skill in the art.  
         [0009]     A variety of cutting mechanisms have been proposed, such as in patent documents U.S. Pat. No. 4,831,732 and GB2288353 (both incorporated herein by reference), and all that is required for such cutting mechanisms is that the cutting member cuts the pipe when rotated about the longitudinal axis thereof.  
         [0010]     What is not appreciated by the prior art is the need for an automated drive for a pipe cutter readily adapted to a variety of drive-power sources.  
         [0011]     Accordingly, there is a need for an improved pipe cutting device.  
       OBJECTS AND SUMMARY OF THE INVENTION  
       [0012]     An object of the present invention is to provide an improved pipe cutting device readily adapted to an automated drive assembly and a variety of drive-power sources, as will be discussed.  
         [0013]     The present invention relates to a pipe cutting device. The device is based on a cutting member having a body with a radial pipe entry slot for receiving a pipe at a required cutting position along its length and having cutting means for cutting the pipe upon rotation of the cutting member around the pipe. The device comprises a drive member having drive means for causing the cutting member to rotate. The drive means is adapted to provide continuous drive to the cutting member body. Drive is not temporarily lost as the pipe entry slot rotates passed the drive means.  
         [0014]     The present invention is based on the desire to provide automated drive to a pipe cutter of the known type described above. The problem addressed is to provide uninterrupted drive to a body having a generally C-shape configuration hich includes a radial slot and in particular to provide drive over the gap in the body defined by the radial slot.  
         [0015]     According to a first aspect of the present invention there is provided a drive device for causing rotation of a cutting member of the type having a body with a radial pipe entry slot for receiving a pipe at a required cutting position along the length thereof, and having cutting means for cutting a pipe upon rotation of the body about a longitudinal axis thereof; the drive device comprising drive means for causing the cutting member body to rotate relative thereto, in which, in use the drive means is formed so as to provide substantially continuous drive to the cutting member body.  
         [0016]     The drive device may further comprise a cutting member. The cutting member may be provided as an integral part of the drive device or may be provided as a separate unit which is associatable with the drive device.  
         [0017]     According to a second aspect of the present invention there is provided a pipe cutting device comprising: a cutting member having a body with a radial pipe entry slot for receiving a pipe at a required cutting position along the length thereof, and having cutting means for cutting a pipe upon rotation of the cutting member about the longitudinal axis thereof; and drive means for causing the cutting member to rotate relative thereto, in which, in use, the drive means is formed so as to provide substantially continuous drive to the cutting member body.  
         [0018]     The present invention therefore provides a device incorporating or adapted to incorporate a cutting member of a known general type in which rotation is used to cut a pipe. Drive means for causing the cutting member body to rotate are provided and as a result the body rotates relative to the drive means. In order to provide substantially continuous drive to the cutting member body the drive means is formed so as to be in substantially continuous driving engagement with the body. Substantially uninterrupted drive is therefore provided to the cutting member body and this facilitates the automation of the cutting process where previously it had not been possible because of the requirement to provide drive across the pipe entry slot as its entrance rotates passed the drive means.  
         [0019]     The drive means may be formed to provide continuous drive by being in continuous driving engagement with the body.  
         [0020]     In order to provide drive to that part of the cutting member body comprising the pipe entry slot the drive means may be adapted to apply drive to the wall of the pipe entry slot. Drive is thereby not temporarily lost when the slot rotates passed the drive means.  
         [0021]     The drive means may include an operative portion adapted to engage the pipe entry slot wall and to apply drive thereto.  
         [0022]     The drive means may include an operative portion which is formed so as drivingly to engage the pipe entry slot as the slot rotates. In this way when the slot passes over the drive means drive to the body is not interrupted.  
         [0023]     The operative portion may comprise a projection, such as a cam, tooth, detent or the like. The operative portion may therefore be formed so as to enter the slot and engage the slot wall to provide drive to the body.  
         [0024]     The cutting member may have a drive surface for receiving drive from the drive means.  
         [0025]     At least part of the drive surface may form part of the body. For example teeth or other projections for receiving drive may be cut into or formed on the body.  
         [0026]     Alternatively or additionally at least part of the drive surface may be formed separate from and be attachable to the body. For example, a jacket-like or strap-like member could be provided for attachment to the body to provide a drive surface. Accordingly an existing cutting member could be retrofitted with a drive surface and the cutting member body requires no modifications.  
         [0027]     The wall of the pipe entry slot may form part of the drive surface.  
         [0028]     The drive means may be provided on a rotatable drive member. The drive member can therefore itself be driven to rotate and this rotation can be transferred, in the form of counter-rotation, to the cutting member by the drive means. A system of counter-rotating wheel-like members is mechanically simple and easy to manufacture.  
         [0029]     In order that the operative portion of the drive means engages the slot at the same point along its rotational path on every rotation it is important that the cutting member and drive member do not slip relative to each other.  
         [0030]     Accordingly the device may be formed so that the relative rotational positions of the cutting member and the drive member can be controlled and precisely determined so that the operative portion of the drive means aligns with the slot each time it rotates relative to the cutting member.  
         [0031]     The cutting member and the drive member may be formed as co-operating cog wheels. Accordingly the drive means include the teeth of the drive member cog wheel which engage co-operating teeth on the cutting member body to transfer rotation. Alternatively, the drive member may transmit rotation to the cutting member at least partly by frictional engagement. Accordingly the drive member and/or the cutting member may be formed from or coated with a material having a high coefficient of friction so that rotation can be transferred.  
         [0032]     The device may include a housing within which the cutting member is rotatable, and the drive means may also be provided in the housing so that the cutting member and the drive member can be placed and held in a required relative rotational position and the device can be supplied as a single unit.  
         [0033]     The device may be motor-driven. Motive power may be provided by any convenient means such as a rotary motor.  
         [0034]     The drive means may be motor-driven. The motor for powering the drive means may be formed as part of the device or may be provided by an external source, with the device adapted to receive drive from that external source.  
         [0035]     The drive means may include a drive shaft which is engageable either by a motor formed as part of the device or engageable by an external drive source. For example, the device may include a drive shaft which is engageable by a power tool such as a drill in which rotation of the drill head can be transferred first to the drive shaft and then to the drive means for transfer to the cutting member body. It should be understood, that in an alternative embodiment such a drill may be used as and understood as an electric motor to drive the drive means. Thus the use of the descriptive phrase “drill” is not limiting to an particular hand drill, or stationary drill but should be broadly understood as an electric motor.  
         [0036]     The cutting member body may be engaged at a single point by the drive means to provide rotation. By engaging the cutting member body only at a single point the complexity of the drive means can be reduced compared to a system involving multiple points of contact.  
         [0037]     Accordingly, substantially uninterrupted drive causing the cutting member to rotate can be provided by the drive mechanism. Powered drive is therefore provided even as the entrance to the slot rotates passed the drive means.  
         [0038]     The drive means may be adapted to provide drive in the absence of direct physical engagement. In this way the problem of engagement over the slot is overcome.  
         [0039]     The drive means may comprise magnetic means for generating one or more magnetic fields and the cutting member may include means responsive to each magnetic field to cause the cutting member to rotate.  
         [0040]     For example the cutting member may be provided with one or more magnetic elements around its periphery and the drive means comprises a series of electro-magnets which can be selectively energised. By selectively energising and de-energising the electro-magnets the magnetic elements could be attracted in a sequence which causes the cutting member to rotate without requiring any physical contact.  
         [0041]     A further possibility to overcome the problem of drive over the slot is to form the cutting member as a flywheel so that sufficient kinetic energy, or a means for imparting sufficient kinetic energy, could be imparted to the member to allow the slot to pass drive means which operate by direct physical engagement, without causing loss of rotation.  
         [0042]     The above and other objects, features and advantages of the present invention will become apparent from the following description read in conduction with the accompanying drawings, in which like reference numerals designate the same elements.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0043]     The present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which:  
         [0044]      FIG. 1  is a diagrammatic section of a conventional pipe cutting member.  
         [0045]      FIG. 2  is a diagrammatic perspective view of the pipe cutting member of  FIG. 1  together with a pipe.  
         [0046]      FIGS. 3A  to  3 D illustrate the working mechanism of a pipe cutting device according to an embodiment of the present invention.  
         [0047]      FIG. 4  is a diagrammatic section of a pipe cutting device including drive means according to an alternative embodiment.  
         [0048]      FIG. 5  is a diagrammatic section of a pipe cutting device according to a further embodiment.  
         [0049]      FIG. 6  is a side elevation of the pipe cutting device of  FIG. 5 .  
         [0050]      FIG. 7  is a diagrammatic front elevation of the pipe cutting device of  FIGS. 5 and 6  shown connected to an external drive source.  
         [0051]      FIG. 8  is a diagrammatic view of the pipe cutting device of  FIGS. 5 and 6  together with an alternative external drive source.  
         [0052]      FIG. 9  is a diagrammatic section of a device according to an alternative embodiment.  
         [0053]      FIG. 10  is a diagrammatic section of a device according to a further embodiment.  
         [0054]      FIG. 11A  is a perspective view of a cutting member formed as part of a cutting device according to an alternative embodiment.  
         [0055]      FIG. 11B  is a plan view of a drive jacket for use in conjunction with the cutting member of  FIG. 11A .  
         [0056]      FIG. 11C  is a perspective view of the cutting member of  FIG. 11A  fitted with the jacket of  FIG. 11B . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0057]     Reference will now be made in detail to several embodiments of the invention that are illustrated in the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. For purposes of convenience and clarity only, directional terms, such as top, bottom, up, down, over, above, front, back, and below may be used with respect to the drawings. These and similar directional terms should not be construed to limit the scope of the invention in any manner. The words “connect,” “couple,” and similar terms with their inflectional morphemes do not necessarily denote direct and immediate connections, but also include connections through mediate elements or devices.  
         [0058]     Referring now to  FIGS. 3A  to  3 D there is shown the principles of the working mechanism behind a pipe cutting device according to an embodiment of the present invention.  
         [0059]     Referring first to  FIG. 3A  there is shown a cutting member  10  of the general type shown in  FIGS. 1 and 2 . A generally circular rotatable drive member  15  is rotatable about a drive axis defined by a drive shaft  20  in the direction indicated by arrow A. The cutting member  10  and the drive member  15  are coated with a material having a high coefficient of friction such that when the drive member  15  is adjacent the cutting member  10  and is rotated, the rotation is transferred to the cutting member  10  to produce counter-rotation in the direction of arrow B.  
         [0060]     The surface of the drive member  15  is smoothly curved with the exception of a tooth  25  which projects at a specified point on the circumference of the member  15  relative to the slot of the member  10 . The tooth  25  includes a ramped surface  26  and an inclined surface  27 .  
         [0061]     As the members  10 ,  15  rotate relative to each other eventually the slot  13  of the cutting member  10  rotates to the point at which the slot  13  starts to rotate passed the driving member  15 . Accordingly the exterior surfaces of the members  10 ,  15  are no longer in direct rolling contact and an alternative way of transferring drive must be provided. The profile and the positioning of the tooth  25  is such that as the slot  13  approaches the driving member  15  the ramped face  26  of the tooth  25  enters the slot  13  and engages the slot wall  14   a  so that the driving member  15  can continue to transfer rotation to the cutting member  10 .  FIG. 3B  shows the relative position of the members  10 ,  15  as the exterior curved surfaces of the member  10 ,  15  lose contact with each other and the tooth surface  26  engages the slot wall  14   a.    
         [0062]     In  FIG. 3C , continued rotation of the driving member  15  now pushes the cutting member  10  via the tooth  25 . The inclined face  27  of the tooth  25  means that the tooth  25  can rotate into the slot  3  freely and without contacting the wall  14   b.    
         [0063]     In  FIG. 3D  the driving member  15  has rotated to the point at which the tooth  25  starts to leave the slot  13  and the cutting member body  12  adjacent the slot wall  14   b  re-engages the driving member  15  so that the transfer of rotation can continue, without having been interrupted by the passing of the slot  13 . The driving member  15  therefore includes the facility to push the cutting member  10  passed the slot  13  and to provide continuous drive.  
         [0064]     The diameters of the cutting member  10  and the drive member  15  are substantially the same, although this is not required in alternative embodiments as will be later described. In addition, the circumferential extent of the tooth  25  is substantially the same as the slot  13  (as shown best in  FIG. 3D ). Accordingly the circumferential length of the members  10 ,  15  in rolling contact with each other as they rotate is substantially equal. Assuming that there is no relative slippage between the members  10 ,  15  this means that the tooth  25  will be at the same point relative to the slot  13  each time the drive member  15  rotates.  
         [0065]     In other embodiments (not shown) the reverse driving arrangement is provided in which the drive member  15  has a recess into which the slot wall  14   a  passes. The wall is then engaged by the recess wall to provide drive.  
         [0066]     Referring now to  FIG. 4  there is shown an alternative drive mechanism. In this embodiment the cutting member  110  and the drive member  115  are formed as cog wheels with the drive member have a plurality of circumferential cog teeth  116  and the cutting member having a plurality of co-operating cog pockets  111  engageable by the teeth  116  to allow the transfer of rotation from the drive member  115  to the cutting member  110  via a cog-teeth engagement mechanism. In this embodiment the driving member also has a tooth  125  of the same type as that shown in  FIGS. 3   a  to  3   d  and the working mechanism is the same. In this embodiment therefore the drive means of the drive member comprise the teeth  116  and the tooth  125  which together provide for the continuous transfer of rotation from the drive member  115  to the cutting member  110 .  
         [0067]     Referring now to  FIG. 5 , a drive member  215  and a cutting member  210  formed according to the present invention are provided. The drive member  215  is Rota table via a drive shaft  220  and includes a tooth  225  for engaging and driving the slot  213  of the cutting member  210  in the same way as described in relation to  FIGS. 3 and 4 .  
         [0068]     While in theory the members  210 ,  215  could be provided separately and brought together at the point of use, it may be preferable for them to be more permanently associated, for example to allow their relative positions to be fixed. In this embodiment the members  210 ,  215  are provided in a housing  230  which is in section generally in the shape of the number eight in outline and together they form a hand-held cutting device generally indicated  250 . The cutting member  210  is rotatably supported in the housing  230  by any convenient means such as rollers (not shown) or the like. The housing  230  includes an opening  235  and the slot  213  of the cutting member  210  can be aligned with the opening  235  so that a pipe (not shown) can be introduced through the opening  235  and into the slot. In some embodiments (not shown) the device includes the facility to ensure that the slot  213  and opening  235  are always aligned when the device  250  is not in use so that the device is always ready to receive a pipe. Following insertion of a pipe the mode of operation of the device is as described in relation to  FIGS. 3A  to  3 D and  FIG. 4 .  
         [0069]     Referring now to  FIG. 6 a  side view of the device  250  of  FIG. 5  shows that the hexagonal drive shaft  220  extends from the housing  230 .  
         [0070]     Referring now also to  FIG. 7  the protruding drive shaft  220  allows the device  250  to be connected to an external drive source, which in this embodiment is a powered drill  240  shown end-on. Rotation of the drill head (not shown) causes the drive shaft  220  to rotate which in turn transfers drive to the drive member  215  and then to the cutting member  210  to effect the cutting of a pipe. In this embodiment therefore the power for the drive member  215  is provided by an external power source which is connectable to the device  250 . In other embodiments (not shown) the power source is provided in the device itself and accordingly the device incorporates a motor or the like as will be understood by those of skill in the art of designing pipe cutting devices to enable a self-contained operation.  
         [0071]     Because the device of  FIGS. 6 and 7  is connectable to an external power source the nature of the power source which drives the device can be selected for a required circumstance. For example, in  FIG. 8 a  drill  340  is connected to the device  350  via a flexible drive shaft  345 , which would allow the device to be operated in confined spaces.  
         [0072]     Referring now to  FIG. 9  there is shown a device according to an alternative embodiment. The embodiment is based on the same type of device shown in  FIGS. 5 and 6  and accordingly a cutting member  410  and a drive member  415  are provided in a housing  430 . A drive shaft  420  extends centrally from the drive member  415 . In this embodiment the housing  430  includes a leg  431  which extends from the side of the housing  430  which accommodates the drive member  415  and results in a generally L-shaped housing.  
         [0073]     The leg  431  accommodates a rotary motor  432  connected to the drive shaft  420 , and a battery  433  for powering the motor  432 . Battery  433  should be understood by those of skill in the art to be readily adaptable as a replaceable or rechargeable battery enabling continuous operation. Alternatively, battery  433  may be replaced by an electric supply cord (not shown) to drive rotary motor  432  in a manner understood by those of skill in the art of designing powered tool mechanism. As an additional benefit, conveniently the leg  431  forms a handle by which the device can be manipulated.  
         [0074]     In use the motor  432  rotates the shaft  420  and the operation of the device is then as described in relation to  FIGS. 5 and 6 .  
         [0075]     In this embodiment therefore the device includes an integral power source and motor for providing drive.  
         [0076]     Referring now to  FIG. 10  there is shown a further alternative embodiment. A housing  530  accommodates a cutting member  510  of the general type shown in  FIGS. 1 and 2 . The cutting member  510  is rotatably supported in the housing  530  on rollers  560 .  
         [0077]     The cutting member  510  has a magnetic element  565  embedded in its surface at a point on its periphery.  
         [0078]     The housing  530  is provided with five electro-magnets  570   a - e  spaced around its interior. The electro-magnets  570   a - e  can be selectively energised and de-energized by a power supply  575  and switching means  580 . The electro-magnets  570   a - e  can be energized to cause the magnetic element  565  to be variously attracted or repelled and consequently rotate the member  510 . By energizing and de-energizing the magnets  570   a - e  in sequence the member  510  can be continuously rotated without physical engagement. This drive mechanism could be used to rotate the member  510  in either direction by changing the sequence of energizing and de-energizing the electro-magnets  570   a - e.    
         [0079]     In yet another alternative embodiment of the present invention, electro-magnets  570   a - e  are removed, and rollers  560  receive a driving force. In such an embodiment, as at least two rollers  560  contact cutting member  510  through out a rotation cycle, rotating power provided continuously vi rollers  560  will smoothly rotate a cutting member without the cost of an electromagnetic assign.  
         [0080]     Referring now to  FIGS. 11A, 11B  and  11 C there is shown a cutting member  610  and an attachable drive surface  690 .  
         [0081]     The drive surface  690  comprises a rubber sheet  691  formed with a plurality of teeth  692  extending transverse its length.  
         [0082]     The surface  690  is sized so that it can be wrapped around the curved exterior of the member  610  to form a drive jacket. The drive surface  690  can then serve to receive drive force from a drive member  115  of the type shown in  FIG. 4  without the requirement for modification of the cutting member body itself.  
         [0083]     Since the sheet  691  is formed from rubber, or other another high molecular weight elastomeric material, it has a high coefficient of friction and relative slippage between the sheet and the member  610  is prevented.  
         [0084]     The surface  690  may be permanently secured to the body, such as by adhesion or welding, or temporarily attaching so as to be removably-attached.  
         [0085]     Those of skill in the art should recognize, that as used herein for the preferred embodiment, the pipe cutting members possess a cylindraceous outer boundary in which the slot penetrates the outer boundary thereof. The descriptive phrase cylindraceous shall be understood as descriptive language referring to a body that has a generally curved outer boundary, and includes elliptical, ovoid, uniform and non-uniform curved boundary forms. Nothing herein should limit the understanding of those skilled in the art of pipe cutting members or drive devices to a uniform shape or continuous or uniform outer boundary, nor shall anything herein require the pipe cutting member to be a geometrically uniform cylinder along its length.  
         [0086]     In the claims, means- or step-plus-function clauses are intended to cover the structures described or suggested herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, for example, although a nail, a screw, and a bolt may not be structural equivalents in that a nail relies on friction between a wooden part and a cylindrical surface, a screw&#39;s helical surface positively engages the wooden part, and a bolt&#39;s head and nut compress opposite sides of a wooden part, in the environment of fastening wooden parts, a nail, a screw, and a bolt may be readily understood by those skilled in the art as equivalent structures.  
         [0087]     Having described at least one of the preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes, modifications, and adaptations may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.