AU780997B2 - Rotational drive means extension device - Google Patents

Description

P/00/01 I Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

*TO BE COMPLETED BY APPLICANT Name of Applicant: THE FENCE PEOPLE PTY. LTD.

Actual Inventor: GARY IAN JONES Address for Service: A.P.T. Patent and Trade Mark Attorneys GPO Box 772, Adelaide, SA 5001 Invention Title: ROTATIONAL DRIVE MEANS EXTENSION DEVICE Details of Associated Provisional Application No PQ2755 dated 10 September 1999 The following statement is a full description of this invention, including the best method of performing it known to me/us:- The present invention relates to an extension device for fitting between a drive means and a tool so that the tool can be rotatably driven by the drive means.

BACKGROUND OF THE INVENTION Power drills are used for a variety of applications that require a rotary motion to drive a tool. Apart from the well known uses with drill bits for drilling holes in materials and with screwdriver bits for use as screwdrivers, power drills may also be used with sanding discs, buffing pads and the like having an extension that can be fitted into the chuck of the power drill. It is also known to drive pumps with a power drill.

In many of the aforementioned uses of power drills, the tool is fitted directly into the chuck of the drill. However there are many uses of power drills where the operator is required to reach up or down to contact the tool with the surface being worked on. For 15 example, one is required to kneel down to use a sanding disc when sanding a floor surface. There are still further situations where it may be required to drill a series of aligned holes through studs in a brick veneer wall so that water or electrical conduit can be fitted. Standard power drills are not suited to these tasks and therefore there is a need for a device that allows the work tool to be maintained at a distance from the drill S 20 itself whilst still being operatively connected to the drill.

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The prior art contains examples of a number of devices that achieve this purpose. In the typical prior art devices an extension shaft is fitted between the chuck of the drill and the working tool, which is typically a drill bit. In use the power drill drives the extension shaft which in turn drives the tool. US 4076444 to Siebrecht, US 5624214 to Carroll and US 3865502 to Hamann all provide examples of extension shafts of this type. In each of these cases the primary use of the extension is to allow the operator to drill elongate channels such as in walls and eaves and the like. In each of these devices the entire extension shaft rotates at the speed of the drill and therefore there is no means for gripping the extension near the drill bit to assist in the positioning and movement of the drill bit. Clearly the longer the extension the more difficult it is to control the placement or movement of the drill bit. This is particularly pertinent when the drill is used for applications such as sanding, buffing or cleaning because those applications in particular require a good degree of control over the placement and movement of the working tool and considerable pressure needs to be exerted radially with respect to the drive shaft.

US 474513 to Salyers addresses a problem with known prior art devices by providing two collars through which the extension drive shaft is journalled. The collars are adapted to be fixed to a wall or the like to maintain stability of the extension and the tool. However a problem with this arrangement is that it is not portable because it is reliant on the collars being fixed to a solid support and therefore it is of limited capacity for use in other applications.

Reference in this specification to a document is not to be taken as an admission that the disclosure therein constitutes common general knowledge in Australia.

OBJECT OF THE TLNVENTION The object of this invention is to provide a rotational drive means extension device that obviates or alleviates any one of the above problems, or at least to provide the public with a useful choice.

SUMMARY OF THE INVENTION 15 For the purposes of this specification the word 'comprising' means 'including but not limited to', and the word 'comprises' has a corresponding meaning.

In one form, although not necessarily the broadest or only form, the invention could be said to reside in an extension device for fitting between a drive means and a tool, the 20 extension device comprising: ."an elongate housing for gripping by hand, a drive shaft aligned with and journalled for rotation within the housing such that a drive means end of the drive shaft extends from a drive means end of the housing for fitting to the drive means, and a tool end of the drive shaft extends from a tool end of the housing and is connected with the tool or may be connected with the tool, ~wherein, in use, the tool is rotatably driven by the drive means and drive shaft.

For the purposes of the following discussion the invention will be discussed in relation to use with a standard power drill. It is found that in use power drills provide a convenient drive means principally because the pistol type grip allows the drill to be held and operated with one hand which frees the other hand to grip the housing.

However it will be appreciated that the drive means is not restricted to power drills and it may be any device that rotates the drive shaft. Other suitable drive means include manual drills or routers.

The tool may be connected to the tool end of the drive shaft using a tool attachment means. In one form of the invention the tool attachment means is a chuck into which a range of tools may be fitted. This embodiment therefore allows a range of common tools such as drill bits, sanding discs and brushes to be fitted to the extension. In the 4 alternative, the tool may be fixedly attached directly to the drive shaft. Thus the tool may be manufactured with a drive shaft integrally formed as part of the tool.

Alternatively the drive shaft may be fitted to a tool using any suitable means which could include the use of adhesives or set screws.

Tools that may be used with the invention include cleaning brushes including nylon or wire brushes of various sizes and configurations, pumps, drill bits, sanding discs, buffing pads, discs with radial nylon line extensions such as those used on Whipper Snippers

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or any other tool for which rotational movement is necessary to work the tool.

The extension can be any suitable length and the length may be dependent on the application for which the extension is used. Thus the tool may be a cleaning brush or .sanding disc and therefore the extension may only need to be in the order of 500 cm in S 15 length to give the operator sufficient reach. Alternatively if the extension is used for •drilling axially aligned holes through studs in cavity walls then it may be more desirable that the extension be between 1 and 2 metres in length. However it will be understood that in many applications the tool itself may be of considerable weight and therefore the longer the extension rod the less control that will be able to be maintained o 20 over the movement of the tool.

In one preferred form of the invention the housing is relatively rigid and provides a support for the tool which in turn may increase the degree of control possible over *movement of the tool. Sufficient rigidity may be provided by a housing made from metal or a hard plastic such as PVC.

The device may include radial positioning means for maintaining the radial position of the drive shaft within the housing. In one preferred form of the invention the positioning means are bushes located within the housing and through which the drive shaft is journalled. The bushes may be annular with the inner diameter of the annulus only slightly larger than the diameter of the drive shaft so that the shaft is able to rotate within the bushing but there is little free play in terms of movement of the shaft radially within the housing. Preferably there is at least a single bush adjacent each of the drive means and the tool ends of the housing. In long extensions it may be advantageous to provide bushings at regular intervals along the length of the housing. Alternatively the guide means may be a single bush which spans the majority of the length of the housing.

The location of the bushes within the housing may determine to some extent the rigidity of the housing and the shaft. Thus it is preferable that bushes are positioned at least adjacent the tool end and the drive means ends of the housing so as to provide rigidity throughout the length of the housing. In particular it is preferable that the chuck of the drill at one end and the tool at the other end are positioned as close as possible to the respective bushes as this tends to maximise the rigidity of the housing and drive shaft.

In another form of the invention bearings may be used instead of bushes. An inner bearing surface may be fixed to the drive shaft, whilst an outer bearing surface may be fixed to the inner surface of the housing.

In one particularly preferred form of the invention the housing covers the length of the drive shaft except for the extensions from the tool and drive means ends. However it may only be necessary for the housing to cover part of the drive shaft, preferably as 15 close as possible to the tool end of the drive shaft to allow housing to be held and thereby used in guiding the tool.

Preferably the extension of the drive shaft from the drive means end of the housing is of a length that permits positioning of the end of the chuck of the drill as close as possible 20 to the bush located at the drive means end of the housing. It is possible that if there is too much of a gap between the end of the chuck and the bush the sharp variation in speed, particularly on starting up the drill, can provide torsional forces that can lead to a bending of the drive shaft.

In a preferred form of the invention the extension device also includes longitudinal "positioning means for maintaining the longitudinal position of the housing with respect to the drive shaft. This allows for a bracing of the tool during work which allows force to be applied to the tool such as in cleaning with a brush.

When the device is in use, the tool or tool attachment may bear against the tool end bush and the drill chuck may bear against drive means end bush to thereby 'lock' the drive shaft longitudinally in the housing. Alternatively, a locking means may be fitted to the drive shaft to hold it longitudinally in the housing. In one form of the invention the locking means is an elastomeric washer which provides an interference fit with the drive shaft and may be fitted between the drive means end bush and the end of the chuck so that the washer provides a connection between the two. In a further alternative form, the locking means is a locking washer having crimpable internal tabs so that the washer may be fitted to either end of the drive shaft and the internal tabs of the washer are bent to provide an interference fit with the drive shaft.

The extension may also include a means for maintaining the drive shaft and housing in alignment with the rotation axis of the drill. This may prevent the extension from moving at an angle from the rotation axis of the drill, which movement may cause the drive shaft to bend or otherwise compromise the integrity of the drive shaft. Thus, in one preferred form of the invention the drive means end of the housing includes a flange which is adapted to fit snugly over at least part of the outer surface of the chuck of the drill. The flange may assist in maintaining the rotation axes of the drill and the drive shaft aligned by maintaining tie hOusing ill aligineii with the rotatio1 axis .he drill. Thus the fitting of the outer surface of the chuck into the flange and the positioning of the end of the chuck as near as possible to the drive means end bush provides a connection between the drill and the extension that tends to minimise any undesirable movement of the extension with respect to the drill.

15 The housing may be formed from any suitable material such as plastics, aluminium, or fibreglass. If the material is heat sensitive such as plastic then it may be necessary to include a heat protection barrier at points in the housing where there may be heat build up such as at the drive means end where friction between the chuck and the housing may lead to a build up of heat.

The drive means may be an electric drill, cordless drill, manual drill, or any other mechanical device that provides the rotational drive necessary to work the tool.

The housing does not necessarily have to be straight and a housing having a bend is also contemplated by the invention. In the case where the housing is bent the drive shaft will be flexible and may be made from a material such as a tight helical wire.

Alternatively, the housing and drive shaft may have at least one flexible region that allows the housing and drive shaft to be bent at varying angles relative to the rotation axis of the drive means. The flexible region may be resiliently flexible so that the part of the housing can be bent by hand to a desired angle and the housing and drive shaft then remain at that angle unless otherwise adjusted.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding the invention will now be described with reference to an illustrated embodiment. The drawings describe an illustrated embodiment wherein, Figure 1 is a side view of a first form of the invention having a chuck and spade bit fitted to the tool end of the extension device, 7 Figure 2 is a part cross sectional side view of Figure 1, Figure 3 is a part cross sectional side view of a second form of the invention having a brush fitted to the tool end of the extension device, Figure 4 is an enlarged part cross sectional side view of the drive means end of the second form of the invention, Figure 5 is an end view from the drive means end of tile extension device of Figure 3, and from the tool end of the extension device of Figure 3, and Figure 6 is a part cross sectional side view of a third form of the invention having a bend in the housing, and Figure 7 is a part cross sectional side view of a fourth form of the invention having a flexible region in the housing, and Figure 8 is a schematic view of various cleaning heads that may be used with the device.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Similar reference characters indicate corresponding parts throughout the several views of the drawings.

"Dimensions of certain of the parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration.

The illustrations show an extension device for fitting between a drive means and a tool to be rotatably driven by the drive means. The drive means is a power drill and in Figures 1 and 2 the tool is a spade bit whilst in Figures 3 and 5 the tool is a cleaning brush The extension device includes an elongate housing through which a drive shaft is coaxially aligned and journalled for rotation. The drive means end of the drive shaft extends from a drive means end of the housing, and a tool end of the drive shaft extends from a tool end of the housing. Bushes (10) act as radial positioning means to maintain the drive shaft in coaxial alignment with the housing and substantially prevent radial movement of the shaft within the housing. In use the drive means rotatably drives the shaft which in turn rotatably drives the tool whilst the housing is substantially prevented from rotation. Thus in using the device the 8 operator is able to hold the drill with one hand and the housing provides a 'handle' that the operator can hold with the other hand.

The drive shaft may be formed from any suitable material and in the illustrated embodiments the drive shaft is formed from 7 mm diameter mild steel rod. This diameter is found to be suitable for fitting into the chucks of most drills.

The drive means end of the drive shaft extends from the bush (10) by an amount that is Sul ilcient for the Shaft to fit comfortably into tlie ChucK (I I) f 1a dri allu sucI tilat when so fitted the end of the chuck (12) is as near as possible to the bush Positioning of the chuck as near as possible to the bush (10) can prevent, as much as possible, any tension in the drive shaft which may lead to undue stress on the drive shaft when it rotates. Positioning of the chuck as near as possible to the bush also S distributes the weight of the extension and tool partly through the bush whereas 15 the farther the chuck is away from the bush, the more the weight of the extension and tool that may be borne by the drive shaft. In the illustrated embodiments the drive shaft extends from the drive means end by 35 mm.

An annular locking washer (13, Figure 4) is fitted between the bush (10) and the end of the chuck. The washer has bendable internal tabs so that as it is inserted onto the shaft the tabs are bent to thereby provide an interference fit with the shaft. The locking washer therefore acts as a longitudinal positioning means in preventing longitudinal movement of the shaft in one direction. The tool abuts the tool end bush to prevent longitudinal movement in the other direction. The locking washer (13) is used in conjunction with an elastomeric washer (18) having an elastomeric face (19) and a metal face wherein the washer is inserted between the bush and the stop so that the elastomeric face bears against the bush. The washer (13) provides a barrier between the bush (10) and the end of the chuck. Preferably there is a gap of about 1 mm between the end of the chuck and the locking washer (13).

An alternative locking means that is not illustrated is an elastomeric washer which is fitted between the bush (10) and the end of the chuck so that the washer provides a barrier between the two. The inner diameter of the washer is slightly less than the diameter of the drive shaft such that the washer can be slid onto the drive shaft and held in place by the interference fit therewith, or may be adhered thereto. In this way the washer acts as a locking means to hold the drive shaft in place longitudinally within the housing. When no washer is used the tool or tool attachment bears against the tool end bush and the drill chuck bears against drill end bush, thus 'locking' the drive shaft into 9 the housing and minimising or preventing longitudinal movement of the rod within the tube.

The bushes (10) are annular and the internal diameter of the annulus is slightly larger than the diameter of the drive shaft so that the shaft is able to rotate within the bushes but there is little free play in terms of radial movement of the drive shaft. In the illustrated embodiments the drive shaft is 7 mm in diameter and the inner diameter of the bushes is 7.5 mm. In the embodiment illustrated in Figures 1 to 3 a bush is fixed within each end of the housing. The bushes form a snug fit within the housing and they are held in place by an interference fit within the housing. Alternatively the bushes may be held in place by adhesives, set screws, or any other suitable means. In the embodiment illustrated in Figure 3 the bushes are wider in diameter than the main body of the housing and the bushes are forced into the housing such that the housing expands around the bushes and holds them firmly in place.

The bushes may be made of a material which provides minimal friction between the bush and the drive shaft. Suitable materials include NylonTM, Teflon'TM, plastics, aluminium or wood.

20 Whilst it is preferable to have bushes at least at the drive means and tool ends of the housing, it is also possible to have bushes spaced at intervals throughout the length of the housing and this may be particularly important with extensions in excess of one metre in length as the greater the distance there is between bushes, the more chance there is of the drive shaft 'sagging'. The greater the number of bushes throughout the length of the housing then the greater the rigidity of the housing throughout its length.

Sagging of the drive shaft can lead to random motions of the shaft when it is rotated o which in turn place undue stress on the drive shaft and can lead to bending or breakage of the shaft. It is also possible to have a single bush which spans the length of the housing.

Annular bearings through which the guide shaft is journalled may also be used in place of bushes. An inner surface of the bearings may be fixed to the drive shaft using any suitable means including adhering, screwing, welding, or keying onto the shaft. An outer surface of the bearing may be fixed inside the housing in the same way as the bushes.

The extension of the illustrated embodiments is formed from 22 mm outer diameter electrical conduit. This provides a substantially rigid housing which lends good support for the tool and allows for good control of movement of the tool. The housing covers the length of the drive shaft except for the extensions from the tool and drive means ends. However it will be appreciated the housing need only cover part of the drive shaft, preferably as close as possible to the tool end of the drive shaft, to allow the housing to be used in guiding the tool.

In the embodiment illustrated in Figures 3 and 5 the drive means end of the housing includes an outwardly flaring flange (14) which is adapted to fit at least partly over the chuck of the drill. The flange flares from 22 mm in diameter to 36 mm at the end of the 5 of e r; -A h- drive housing. The flang nssists in mainta;ni;ng the rotation axes of t drill and tah drive shaft aligned by maintaining the housing in alignment with the rotation axis of the drill.

The flange accommodates chucks of different sizes which therefore increases the range of drills that may be used with the extension.

The flange may also contain a heat protection barrier (16) which is the same shape as 15 the flange and can be fixed inside the flange. The heat protection barrier protects the flange and the housing from heat degradation resulting from friction between the flange and the chuck. This may be particularly useful where the housing is formed from !°:°-plastic. The flange may be formed from any material with suitable thermal barrier properties including, but not limited to, aluminium.

The housing may be formed from any suitable material such as plastics, aluminium or fibreglass.

In the embodiment illustrated in Figures 1 and 2 a standard tool in the form of a spade bit is attached to the extension through a tool chuck The tool chuck is connected to the tool end of the drive shaft by welding, or using set screws through the side of the chuck and into the drive shaft. This particular form of the invention therefore allows a number of standard tools to be connected to the extension which thereby provides great flexibility in the uses of the extension.

In the embodiment illustrated in Figures 3 and 5 the tool is in the form of a brush, the core of which is fixedly attached to the drive shaft. The tool may be manufactured with the drive shaft integrally formed or the drive shaft may be fitted to the brush using any suitable means which could include the use of adhesives or set screws.

The embodiment illustrated in Figures 1 and 2 may be used for drilling elongate holes through studs in walls for example. Thus the fitting of electrical or other conduit into brick veneer walls requires a set of aligned holes to be drilled in studs. This embodiment therefore allows aligned holes to be drilled by providing an extension that 11 is rigid which therefore leads to alignment of the holes. For this purpose an extension of one metre or more in length may be needed.

The embodiment illustrated in Figures 3 and 5 is particularly suitable for cleaning surfaces such as windows, swimming pools, driveways and the like. It is also particularly suitable for internally cleaning pipes and the like. In this case the length of the extension is 500 mm. An advantage of the extension is that it allows the user to hold the extension at a point just behind the back of the brush when then allows good control to becxcIcisd overthe movement of the b-ush. This is to be conti-asted with the known prior art devices which do not allow the user to hold the extension close to the brush.

Figure 8 shows various shaped brushes that may be used with the extension device for the purpose of cleaning. Cleaning heads depicted in Figures 8 and have 15 relatively soft bristles and may be used for general domestic and/or industrial cleaning purposes. Cleaning heads depicted in Figures 8 and are smaller than those in eoel Figure 8 and and are particularly useful for cleaning in corners in bathrooms, swimming pools or the like. The head depicted in Figure 8 contains relatively soft bristles and is suitable for general cleaning, whilst the head depicted in Figure 8 (c) contains relatively stiff wire bristles and is useful when greater abrasion is required.

The cleaning head depicted in Figure 8 contains relatively soft bristles and is useful for cleaning channels such as gutters or the like.

The drive means may be an electric drill, cordless drill, manual drill, or any other mechanical device that provides the rotational drive necessary to work the tool.

Figure 6 shows an embodiment wherein the housing is bent slightly. In this case the drive shaft is flexible and may be made from a material such as is used in plumbing routers. This embodiment is useful with a cleaning head because the angle of the housing allows the cleaning head to reach hard to reach areas such as in gutters. In an alternative form that is illustrated in Figure 7, the housing has a flexible region (17) and the drive shaft is flexible so that the housing can be bent at varying angles. The flexible region may be resiliently flexible so that the housing can be bent to a desired angle and it then stays in that position until it is otherwise altered. The flexible region may be made form a resilient material that is concertinaed to allow for bending at various angles. The flexible region may thus be fixed at an intermediate position in the housing, preferably toward the tool end of the housing.

Various features of the invention have been particularly shown and described in connection with the exemplified embodiments of the invention, however, it must be understood that these particular arrangements merely illustrate and that the invention is not limited thereto and can include various modifications falling within the spirit and scope of the invention.

Claims (20)

1. An extension device for fitting between a drill chuck and a tool, the extension device comprising: an elongate single piece tubular housing for gripping by hand, a drive shaft aligned with and journalled in either brushes or bearings for rotation within the housing such that a drive means end of the drive shaft extends from a drive means end of the housing for fitting to the drive means, and a tool end of the drive shaft extends from a tool end of the housing and is connected with the tool or may be connected with the tool, wherein, in use, the tool is rotatably driven by the drive means and drive shaft, and a flange at the drive means end of the housing is adapted to fit snugly over at least part of the chuck of the drill to assist in maintaining the rotation axes of the drive means and the drive shaft aligned.

2. An extension device as claimed in claim 1 including a protection barrier fixed inside of the flange to protect the flange from heat degradation resulting from friction between the flange and the chuck. 20

3. An extension device as in either claim 1 or 2 wherein said housing is deformable said brushes or bearings forced into either end of the housing outwardly deforming the housing to locate the brushes or bearings.

4. An extension device as claimed in any one of claims 1 to 3 wherein the housing is relatively rigid and is able to support the weight of the tool when held by the drive means alone.

An extension device as claimed in any one of claims 1 to 4 wherein located within the housing are one or more bushes through which the drive shaft is joumalled for rotation. 14

6. An extension device as claimed in any one of claims 1 to 5 wherein a respective single bush is located adjacent each of the drive means end of the housing and the tool ends of the housing.

7. An extension device as claimed in either claim 1 or 5 wherein located within the housing are one or more bearings through wMlich the drive shaft is journalled, the bearings having an inner bearing surface fixed to the drive shaft and an outer bearing surface fixed to an inner surface of the housing.

8. An extension device as claimed in any one of claims 1 to 7 6 wherein the tool is permanently attached directly to the drive shaft.

9. An extension device as claimed in any one of claims 1 to 8 wherein the extension includes a tool attachment means for connecting the tool to the tool end of the drive shaft.

An extension device as claimed in claim 9 wherein the tool attachment means is a shaft chuck into which a range of tools may be fitted.

11. An extension device as claimed in any one of the preceding claims wherein the 20 housing covers the length of the drive shaft except for a portion at the drive means ends for connection with the drive means.

12. An extension device as claimed in any one of the preceding claims wherein a locking means holds the drive shaft in place longitudinally in the housing.

13. An extension device as claimed in claim 12 wherein the locking means is a washer that provides an interference fit with the drive shaft.

14. An extension device as claimed in any one of claims 1 to 13 wherein at least part of the housing is bent at an angle from the rotation axis of the drive means.

An extension device as claimed in claim 14 wherein the housing and drive shaft have at least one flexible region that allows the housing and drive shaft to be bent at varying angles relative to the rotation axis of the drive means.

16. An extension device as claimed in claim 15 wherein the flexible region is resiliently flexible so that the part of the housing ca be bent by hand to a desired angle and the housing and drive shaft remain at that angle unless otherwise adjusted.

17. An extension device as claimed in any one of claims 1 to 16 wherein the housing is formed from plastics tubing deformable on heating.

18. An extension device as claimed in any one of the preceding claims wherein the drive means is selected from the list including electric drill, cordless drill, manual drill and router.

19. An extension device substantially as described hereinbefore with reference to the accompanying drawings.

20 Dated this 12th day of January 2005 The Fence People Pty Ltd S* By their Patent Attorneys o* 25 A. P. T. Patent and Trade Mark Attorneys