Wall chaser Field of the Invention

The present invention relates to a wall chaser and particularly to a wall chaser with improved safety characteristics. The invention also relates to an insulating hood that may be used with wall chasers to improve the safety during use of such wall chasers. The invention also relates to a handle coupling mechanism for a wall chaser that minimises vibration issues for the user of the chaser and also prevents generation of an electrical path through the handle from the chaser housing.

Background

Wall chasers are a type of specialist power tool that are used for cutting a groove into a wall. Typically they are used for cutting narrow grooves in walls for the placement of electrical cables or the like. They are conventionally used by electhciansl. An electrical motor is providing in a motor housing which is coupled via a gearbox to a chaser housing where it drives one or more discs which are used for cutting into the wall. Where two or more discs are provided, the chaser housing is dimensioned such that the two or more discs can be mounted in an arrangement whereby they are spaced apart sufficient to define a groove in the wall. Once the cut has been defined in the wall and the necessary work conducted, be that the insertion of cabling or the like, the wall can be plastered again to provide the finished surface.

The chaser is typically used to cut along a vertical wall. There is a typical requirement for the cut to be a straight cut. Any vibration in the housing can affect the ability of the user to maintain the grip on the chase and the ability to maintain the straightness of the cut. Another problem may arise in the context of electrocution. The cutting of grooves into walls where it is not known what is below the surface of the wall could result in an accidental cutting of existing power cables with the result that the housing may become live and if touched by the user would result in an electrical shock to the user.

There are therefore a number of problems associated with wall chasers.

Summary These and other problems are addressed by a wall chaser in accordance with the present teaching which comprises a chaser housing for one or more cutting members, a handle for holding the chaser, the handle being provided above the housing such that the housing is provided between the at least one cutting members and the handle, and wherein the chaser further comprises an electrically insulating cover for the housing, the cover being disposed between an upper surface of the housing and the handle to obviate an accidental touching of the housing surface by a user holding the handle.

The housing is desirably metallic and typically provided in aluminium.

The cover is desirably formed from an insulating rubber. The cover is desirably provided in the form of a hood defining an interior volume corresponding in shape with the shape of the outer surface of the housing such that when received onto the housing interior surfaces of the cover are in intimate contact with the outer surfaces of the housing.

The cover and housing are desirably formed separately, the cover being subsequently affixed to the housing using a glue or other fixing arrangement.

The hood desirably comprises a mouth providing access to the interior volume of the hood, the mouth being operably presented to an upper surface of the housing and dimensioned so as to be receivable over an upper portion of the housing. The depth of overlap is defined by the length of the side walls of the hood and is desirably such that the hood will overlap with at least an upper third of the housing.

Desirably the hood is moulded. Exterior surfaces of the hood may be textured to improve the friction characteristics of the surface.

In another arrangement an insulating cover for a wall chaser is provided, the cover being dimensioned to be receivable over an upper surface of a chaser housing, provision of the cover on the housing providing an insulating surface between a handle provided above the housing and the housing. In this way the risk of a user who is grasping the handle making contact with the metallic surface of the housing is reduced.

The invention also provides a coupling arrangement for a chaser handle which serves to insulate the handle from the chaser housing. The coupling arrangement comprises an insulating rubber coupler which is attached at a first end to the chaser housing and at a second end to the handle. The coupling mechanisms for the first and second ends are separate and are not in contact with one another. In this way any electrical potential at the housing end will not be transferred through the coupler to the handle. The rubber is desirably of an electrically insulating grade and desirably also provides vibration dampening so as to minimise any transfer of vibration of the chaser housing resultant from operation of the chaser through to the handle.

These and other features of the present invention will now be described with reference to an exemplary arrangement thereof which is provided to assist in an understanding of the teaching of the invention but is not intended to be construed as limiting the invention to the exemplary arrangements which follow. Brief Description Of The Drawings

The present invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a side view of a chaser in accordance with the present teaching.

Figure 2 is a top view of the chaser of Figure 1.

Figure 3 is a perspective view from one side of a cover component of the chaser of Figure 1.

Figure 4 is a perspective view from the other side of the cover of Figure 3. Figure 5 is a front and side perspective view of the chaser of Figure 1.

Figure 6 is a rear view of the chaser of Figure 1.

Figure 7 is a perspective view of a coupling arrangement in accordance with the present teaching.

Figure 8 is a section through the coupling arrangement of Figure 7

Detailed Description Of The Drawings

Figure 1 shows a wall chaser 100 which comprises a chaser housing 110 for housing one or more cutting members 120. In the arrangement of Figure 1 , two cutting members are provided and arranged parallel to one another such that operation of the chaser will provide a cutting of two parallel lines within the surface of the wall. The cutting members are desirably of the type known as abrasive or diamond tipped blades. The chaser of Figure 1 is a hand held power tool and comprises first and second handles for enabling a user to control the chaser during operation. A first handle 130 is coupled to a motor body 140 portion of the chaser and is provided between the motor body 140 and a power cable 145 which is used during operation of the chaser for providing power to the electrical motor within the motor body. The motor body 140 is coupled via a gearbox 150 to the drive mechanism for the cutting members and as will be appreciated by those skilled in the art the motor body 140 is conventionally double insulated to prevent electrical leakage into the gearbox 150 or motor body. Such electrical leakage could occur by accidental cutting of power cables within the wall during operation of the chaser.

The chaser housing 110 comprises a stationary main body portion 112 and a moveable skirt 113. The moveable skirt is desirably pivotable about a pivot point 114 located to the rear of the chaser housing, the movement being defined in an arc controlled by the movement of a locking nut 115 within an channel 116 defined in the main body portion. The relative movement of the skirt 113 to the main body portion provides for ease of access to the cutting members 120 during times of removal of these cutting members.

The chaser may include an exhaust 150 which is in communication with an interior volume 155 of the chaser housing and provides for a redirection of any debris resultant from operation of the chaser to a collection bag (not shown) which is operably coupled to the exhaust and provided to the rear of the chaser housing.

A second handle 160 is located above the chaser housing, and as shown in the top view of Figure 2 extends transverse to the longitudinal axis of the chaser. The second handle 160 is typically located above the axis of rotation of the cutting members and allows the user to direct force downwardly at the point of cutting. The user will typically grasp the chaser at the first and second handles, powering the chaser from a power controller 131 provided adjacent to the first handle 130 and directing the chaser with the second handle 160.

It will be appreciated that a chaser such as that described heretofore is not that different to conventional chasers. It will also be appreciated from an inspection of Figures 1 and 2 that a user grasping the second handle 160 could accidentally touch an upper region 117 of the housing 110. This could happen during the gripping of the handle or by extension of their fingers while grasping the handle. In the event that the housing was electrically live, such touching of the surface of the housing could result in a shock to the user, which depending on the extent of the shock could potentially be fatal.

To address such an issue the present invention provides an electrically insulating cover 180 provided between the handle 160 and the housing 110. The cover is desirably formed from an insulating rubber material. The rubber will have sufficient thickness and insulation properties to prevent a user touching an outer surface 181 of the cover from receiving a shock if the inside surface of the cover is in intimate contact with a live housing. By using a rubber material the cover may be moulded to replicate the shape of the housing. Rubber being a resilient and flexible material can be extended when presenting the cover to the housing so as to allow the cover to be seated on and engage with the housing. Once fully mated the rubber will contract to ensure a tight fit. This engagement can be made more secure by providing an adhesive contact between the inner surface of the cover and the outer surface of the housing which when cured will reduce the possibility of the cover being removed from the housing.

Figures 3 and 4 show exemplary arrangement of a cover that may be usefully engaged with a chaser housing to prevent a user receiving an electrical shock in circumstances when the housing becomes electrically live. It will be appreciated that the actual dimensions of covers will depend on the shapes and contours of the housing with which they are intended to be used. Nevertheless typically each cover will define mouth 300 providing access to an interior volume 310 of the cover. The cover will desirably have first and second side walls 320, the depth of which will define, in use, the degree of overlap between the cover and the chaser housing. The side walls meet at an upper surface 330 which is typically curved in shape, so as to correspond with the shape of the upper surface of the chaser housing. At a rear surface 340 of the cover, a cut out portion 350 is defined within which the exhaust 150 will be received. In use the cover will be presented downwardly over the cover until the upper surface of the cover meets with and abuts with the upper surface 117 of the housing. The chaser exhaust will pass through the cut out 350 and abut against a cap 355. defined in the cover- as shown in Figures 1 and 2. In this way lateral movement of the cover relative to the housing is restricted by contact between each of the side walls of the cover with the corresponding side walls of the housing and by the engagement of the exhaust with the cut out and cap elements of the cover.

The cover has a front portion 360, that similarly to the other components of the housing is dimensioned to correspond with corresponding surface of the chaser housing, in this case the upper front surface of the chaser housing. At a lower surface 365 of the front portion 360 a cut out portion 366 is defined which when the chaser cover is fully seated on the chaser housing will abut against the locking nut 115. The degree of overlap of the cover with the chaser housing is thereby defined by the height of the side walls 350, the distance of the locking nut 115 from an upper surface of the chaser housing and the positioning of the chaser exhaust relative to the chaser housing. The contours of inner surfaces 370 of the cover desirably mirrors the outer surfaces of the chaser housing, such that once presented the inner surfaces 370 of the cover will be in intimate contact with the outer surfaces of the chaser housing.

It will be seen from an inspection of Figures 1 through 5 that the electrically insulating cover for the housing is disposed between an upper surface of the housing and the handle to obviate an accidental touching of the housing surface by a user holding the handle. The degree of overlap is typically at least such as to cover the upper third of the chaser housing and desirably upto the top half of the housing. In this way a user gripping the handle 160 will not accidentally come into contact with exposed metal surfaces of the chaser housing. It will be appreciated that the chaser housing is desirably fabricated from metal such that in case of the cutting members 120 breaking that shards of the moving cutting members will be contained within the interior volume of the chaser housing and will not cause damage to the operator of the chaser. To further prevent the user of the chaser receiving electrical shocks in circumstances where the chaser housing becomes electrically live another embodiment of the present teaching electrically isolates the handle 160 from the chaser housing. As shown in Figure 6, which is a rear view of an exemplary chaser, the handle 160 is desirably orientated to be over the chaser housing 110. The handle 160 is desirably orientated to be parallel with the axis of rotation of the cutting member, shown in Figure 6 as the line X-X'. To provide this orientation of the handle 160 relative to the housing 110 , the handle is provided on a support arm 600 that is coupled at a first end 605 to the chaser handle 160 and at a second end 610 to a rubber anti-vibration coupling arrangement 630. This coupling arrangement or buffer for the chaser handle serves to electrically isolate the handle 160 from the chaser housing 110. As shown in Figures 7 and 8 such a coupling arrangement comprises an insulating rubber core 700 providing female threaded connectors 705, 710 at opposite sides thereof. Corresponding male connectors are receivable within these connectors and the coupling arrangement is attached at a first end 710 to the chaser housing and at a second end 705 to the handle support arm 600. The coupling mechanisms for the first and second ends are separate and are not in contact with one another. In this way any electrical potential at the housing end will not be transferred through the coupler to the handle. The rubber is desirably of an electrically insulating grade and desirably also provides vibration dampening so as to minimise any transfer of vibration of the chaser housing resultant from operation of the chaser through to the handle.

It will be appreciated that what has been described herein are exemplary arrangements of a cover that may be used to obviate a user of a wall chaser becoming electrocuted through contact with a live chaser housing. By providing such a cover- typically about 2mm in thickness of an electrical grade rubber, between the handle of the chaser and the chaser housing, the user of the chaser will be insulated even if they accidentally touch the chaser housing. In another arrangement a coupling arrangement for coupling the handle to the chaser housing is provided, the coupling arrangement again serving to electrically isolate the handle from the chaser housing. In a preferred arrangement both the cover and the coupling arrangement will be used in tandem on the same chaser but it will be appreciated that chasers could be provided with one or other of the two elements, each serving to protect the user from different possibilities of electrical shock. In the first instance the elastomeric nature of the rubber ensure a tight fit between the cover and the chaser housing obviating the possibility of the two becoming separated after extended periods of usage. A secondary advantage of such a cover is that the rubberised exterior of the cover will serve to protect the chaser housing from damage during accidental dropping or the like. In the coupling arrangement the rubber also provides a dampening of the transmission of any vibration of the chaser housing through to the handle, providing the user with more comfortable operation of the chaser.

While the cover may be provided on the chaser at the time of manufacture, such covers could also be provided as a retro-fit component for use with existing chasers. In such circumstances the user of the chaser would simply locate and secure the cover onto their existing chaser.

While preferred arrangements have been described in an effort to assist in an understanding of the teaching of the present invention it will be appreciated that it is not intended to limit the present teaching to that described and modifications can be made without departing from the scope of the invention.

The words comprises/comprising when used in this specification are to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers , steps, components or groups thereof.