EP0115492A1

EP0115492A1 - An attachment for a powered tool

Info

Publication number: EP0115492A1
Application number: EP83902236A
Authority: EP
Inventors: Norman Kaye Wright
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-07-28
Filing date: 1983-07-25
Publication date: 1984-08-15
Also published as: WO1984000575A1; EP0115492A4; JPS59500963A

Abstract

Une fixation (2) pour un outil à entraînement mécanique, tel que par exemple un outil de creusement de trous de poteaux, comprend un berceau (6) permettant de monter de manière pivotante l'outil sur la fixation (2), un assemblage de support (10) possédant des éléments de contact avec le sol, par exemple des roues (34), conférant mobilité et stabilité à la fixation, et un organe de cadre allongé (8) reliant le berceau et l'assemblage de support et possédant des organes permettant de fixer de manière libérable le berceau à une extrémité de l'organe de châssis ainsi qu'un organe permettant de fixer de manière libérable l'assemblage de support (10) à une autre extrémité du même organe.A fastener (2) for a tool with mechanical drive, such as for example a tool for digging post holes, comprises a cradle (6) making it possible to pivotally mount the tool on the fastener (2), an assembly of support (10) having elements in contact with the ground, for example wheels (34), giving mobility and stability to the attachment, and an elongated frame member (8) connecting the cradle and the support assembly and having means for releasably securing the cradle at one end of the frame member and a means for releasably securing the support assembly (10) at another end of the same member.

Description

"AN ATTACHMENT FOR A POWERED TOOL"

The present invention relates to attachments for use with powered tools, and more particularly relates to an attachment for use with a post hole digger having its motor connected to an auger. Post hole diggers are usually provided as self-contained "units having a motor and an auger arranged in line so that the motor drives the auger more or less directly. Handles are provided on either side of the digger so that the operators may grasp them in order to control and stabilise the digger in operation. Usually, it requires two men to control the digger, one on either side, with each operator holding onto one of the handles provided. However, the post hole digger is not at all easy to control and requires great care in order for it to be operated safely. Such post hole diggers when designed for two man operation are very rarely, if at all, capable of being used by one man. In the event that one man operation is possible, such operation is extremely hazardous for a number of reasons.

An attempt to provide for easier operation of the post hole digger, and to provide for single handed operation was to incorporate a motor and an auger 2 separately at remote locations from each other on a frame with a drive shaft connecting the motor and the auger. Such an arrangement while capable of being operated by one person, was not entirely satisfactory since this post hole digger was very large and cumbersome requiring a great deal of manhandling by usually more than a single operator since the framework was constructed of quite large structural members. Furthermore, because the motor was remote from the auger, this machine requires considerable maintenance due to the need to provide a drive shaft, together with its associated parts, and due to vibrations caused by the arrangement.

The present invention, o the other hand, provides a lightweight, portable attachment for use with a post hole digger that can be managed quite easily and safely by a single operator since it is strong, manoeuverable and relatively maintenance-free. Therefore, it is an aim of the present invention to provide an attachment for a powered post hole digger which at least alleviates some of the problems of previously available attachments for post hole diggers and post hole digger machines.

According to the present invention there is provided a substantially elongate attachment capable of receiving a powered tool, comprising a holding means located towards one end of the attachment for pivotally connecting the power tool to the attachment, a support assembly located towards the other end of the attachment for supporting the attachment on a work 3 surface, and an elongate member interconnecting the holding means and the support assembly.

According to a further aspect of the present invention there is provided a modular, portable attachment capable of receiving a power post hole digger, comprising an elongate member having located at one end a demountable holding means for pivotally connecting the post hole digger to the attachment, and a mobile support assembly demountably located at the other end of the elongate member for supporting the attachment on a work surface, wherein in use the holding means and the support means are interconnected by the elongate member, said mobile support assembly having movable ground contacting elements.-

*• According to another aspect of the present invention there is provided a modular support for a power tool having a motor directly connected to a working element, the support comprising a base portion having a work surface engaging element which contacts the work surface in use, an elongate arm having one end capable of being releasably securable to the base portion, and a tool mounting portion capable of being releasably secured to the other end of the elongate arm, said tool mounting portion comprising a frame having means for releasably securing the frame to the end of the arm in use and at least one mounting lug for being received in at least one corresponding slot of the power tool, the lug being pivotally connected to the frame so that the tool may pivot with respect to the frame when in use in the frame, the base portion, the arm and the mounting portion being 4 connected to each other in an assembled configuration and being capable of adopting a disassembled configuration for transport or storage when not in use. The invention will now be described by way of example with reference to the accompanying drawings in which:

FIGURE 1 is a side elevational view of one form of the attachment together with a power post hole digger in position;

FIGURE 2 is an exploded perspective view of the attachment of Figure 1 from which the power post hole digger has been omitted for clarity.

In Figure 1, there is shown an attachment generally denoted as 2 , having fitted to it a power post hole digger generally denoted as 4 comprising a motor 3 and an auger 5. Attachment 2 comprises basically, a hooplike cradle 6 for receiving the post hole digger; a rectangular or square section elongate framework member 8; and a substantially triangular supporting assembly 10 for supporting the attachment on a work surface. The cradle 6, the framework member 8 and the supporting assembly 10 are designed so that they may be assembled together to form the attachment in use, or disassembled into the three component parts for transport or storage.

In Figure 2, in combination with Figure 1, there is shown a handle 12 fixedly connected to cradle 6 so as to extend outwardly from the attachment. Handle 1 is off-set to the common place of the cradle and framework member to extend outwardly at an angle from 5 the attachment. Rods 14 are pivotally mounted on either side of cradle 6 by means of pivot pins 16 which pass through the respective sides of cradle 6 and respective rods 14 on either side. Although not shown in Figure 2, the power post hole digger is connected to rods 14 by means of bolts 18 located through rods 14 in use. Bolts 18 which pass through corresponding apertures in the post hole digger fixedly hold the digger to the rods. Bolts 18 pass through rods 14 substantially at right angles to pivot pins 16. Rods 14 take the place of the conventional handles provided with conventional post hole diggers so that the post hole digger requires no modifications to be connected to the cradle. Since rods 14 can pivot in cradle 6, the digger when in position also pivots in cradle 6 in the direction of Arrow A of

Figure 1.

A tubular extension 20 is welded to the hooplike cradle 6 on the opposite side to that which handle 12 is attached in order that the cradle may be assembled to framework member 8. The elongate framework member

8 which in the embodiment described is hollow is provided at one end with a tubular insert 22 located inside the hollow section of the member. The external diameter of tubular extension 20 is slightly less than the internal diameter of tubular insert 22, so that the extension 20 may be received inside insert 22 when the cradle is connected to the framework member in an assembled configuration of the attachment. A pair of aligned apertures 24 are provided in extension 20 and a pair of aligned apertures 25 are provided in insert 6 22 so that a bolt (not shown) may pass through the two aligned aperture pairs when both pairs are aligned when extension 20 is in insert 22 to securely locate the extension in the insert. A male projection 26 of reduced dimensions to that of the main part of framework member 8 and of correspondingly shaped cross-section is provided at the other end of framework member 8. The reduction in dimensions of projection 26 corresponds to the thickness of the wall of the hollow -rectangular framework member 8 so that projection 26 acting as a male member is receivable in the hollow web 28 acting as a corresponding female member. A pair of aligned apertures (not shown) is provided in projection 26 for securely attaching projection 26 in web 28.

Supporting assembly 10 comprises a length of hollow rectangular section framework acting as a web 28 corresponding to the size of the main portion of framework member 8, connecting a pair of bracing plates 30 which extend outwardly and downwardly from the web 28, and an axle 32 which extends between a pair of ground wheels 34. The axle 32 is supported at its respective ends by the respective lower ends of the pair of plates 30. Web 28 is provided with a pair of aligned apertures (not shown) so that when the attachment is in an assembled configuration, male projection 26 is received in the end of web 28 and a bolt (not shown) is passed through the aligned pairs of apertures to securely fasten the support assembly 10 to the framework member 8 in a similar fashion to that of projection 20 and insert 22. 7 The attachment is portable since it is stored in

3 separate component parts; the cradle, the framework member, and the support assembly. In use, the attachment in its disassembled configuration is transported to the work place by any suitable means, such as for example, in the boot or trunk of a car or similar. At the work place, the attachment is assembled by first, if necessary, fitting the power post hole digger to the cradle if it is not already attached by first removing the auger from the digger and removing the conventional handles of the digger, then attaching the digger to rods 14 by bolts 18.

.When the digger without auger is in the cradle, the cradle is connected to the framework member 8 by the ^' extension 20 fitting into the insert 22 and being fastened securely. The framework member 8 is connected to the support assembly 10 by means of projection 26 being received in web 28 and securely fastened. The attachment is now in its fully assembled configuration. The auger of the post hole digger may then be fitted to its motor and the attachment complete with power post hole digger is ready for operation when fitting the auger to the motor it is possible to either fit the auger into the motor output shaft directly, or fit an optional frangible coupling arrangement between the motor output shaft and the auger. The optional coupling comprises two separate parts which are releasably interconnectable. The first part which is connected to the output shaft of the motor comprises a male member similar to the male member on a conventional 8 auger so that the first part of the coupling may be received in a correspondingly shaped female socket of the output shaft and a collar arrangement fixedly secured to the male member. The collar arrangement has a key which is engagable with a corresponding key of the output shaft located at one end and is provided with a socket at the other end. The second part is correspondingly shaped to the first part. The two parts are connected together by means of a shear pin which is received through aligned apertures of the first and second parts. The shear pin provides additional safety in that if the auger in operation is prevented from rotation, the shear pin will break due to the torque applied by the motor output shaft. When the work is finished, the attachment may be disassembled into its component parts for transportation or storage.

The advantages of the described embodiment of the present invention are (1) One man may safely operate the post hole digger in the attachment whereas with conventional post hole diggers two men are required to operate the digger, and even then there is a safety risk to the operators; (2) The attachment can receive any conventional post hole digger having an integral motor and auger since no modifications are required to the digger apart from removing the handles supplied with the conventional digger since rods 14 of the present invention replace the conventional handles; 9 Even if some modifications are required to the digger, such modifications are minimal and are associated with connecting the post hole digger to the cradle and not to the operational parts of the digger such as the motor or auger;

(3) The attachment is portable as it can be disassembled into its component parts for easy storage and transportation;

(4) The attachment of the present invention is maintenance free since there are very few moving parts which are under stress;

(5) The attachment may be used with many brands of post hole diggers which are presently numerous and used in large quantities. The described arrangement has been advanced merely by way of explanation and many modifications may be made thereto.

One such modification to the present invention is to provide an additional tubular extension tube 20 to that already provided, and located on the opposite side of cradle 6 to the first extension tube 20 i.e. the additional extension tube is located the same side of the cradle 6 as the handle 12 which is slightly off-set beneath in use the lengthwise extending axis of the framework member so that the cradle may be attached to the framework member 8 with the handle located immediately underneath the framework member. In this configuration the attachment may be positioned close to a wall or similar obstruction to enable the hole to be bored without the handle interferring. A small bracket is located on the underside of the 10 framework member for receiving the handle to provide additional support and rigidity for the post hole digger.

Another such modification is the provision of a retaining means such as stakes or brackets or similar located along the length of the arm to provide a load-bed for carrying a load such as wooden posts or similar.

Another such modification is the provision of one or more elongate arms having correspondingly shaped male and female ends for engaging with each other so that the overall length of the attachment may be lengthened if desired. Such one or more extra elongate arms may have male ends identical to male projection 26 and female ends identical to the hollow end of web 28.

Another such modification is the provision of a balance counter weight adjustably connected to the web 28 of the attachment so that the attachment in use could be counter balanced in use by adjusting the counter weight relative to the support assembly to lie in various positions with respect to the axle 32 to provide different amounts of counter balancing weights. One such arrangement of balance weights is a T-shaped member in which the upright is similar in shape and dimension to that of projection 26 so that it may be received in the free end of web 28 to extend outwardly from the attachment opposite to that of framework member 28. The balance weight may be slidably received, inside web 28 to adopt various 11 positions to alter the counter balance ef fect as desired.

These and other modifications may be made without departing from the spirit and scope of the invention which includes every novel feature and combination of novel features herein disclosed.

Claims

12 CLAIMS :

1. An attachment for a powered tool comprising a support assembly having a work surface contacting element which contracts the work surface in use, an elongate member having means at one end for releasably securing the support assembly thereto, and a tool holding portion capable of being releasably secured to another end of the elongate member, said tool holding portion being pivotable with respect to the attachment so that the tool may pivot with respect to the attachment in use.

2. An attachment according to claim 1 in which the ^'holding portion comprises a frame having means for releasably securing it to the elongate member, and at least one mounting lug for engaging with the tool, the lug being pivotally connected to the frame

3. An attachment according to claim 2 which is modular so that the elongate member, support assembly and holding means may be interconnected to each other is an assembled configuration and be capable of being dissassembled for transport or storage.

4. An attachment according to claim 1 in which the frame is a hooplike cradle having pivoting means located on opposite sides thereof, said pivoting means permitting pivoting of the tool with respect to the attachment, and releasable engaging means located

_ OMP 13 intermediate the pivoting means for releasably connecting the cradle to the elongate member.

5. An attachment according to claim 4 in which the frame is provided with two releasable engaging means located substantially opposite each other and located intermediate the pivoting means so that the cradle may be releasably connected to the elongate member in two configurations.

6. An attachment according to claim 1 in which the cradle which is in a common plane with the elongate member is provided with a handle off-set to- the common plane.

7. An attachment according to claim 1 having a counter balance weight means adjustably connected to the support assembly.

8. An attachment according to claim 7 in which the counter balance weight means is a substantially T-shaped member being selectively located on the support member to vary the amount of counter balance.

9. An attachment according to claim 6 in which the handle is provided to allow for manual or hand held operation of the attachment.

10. An attachment according to claim 2 or 5 or 8 in which there is a frangible coupling connected to the tool,, the coupling being provided with shear means to

QMPI_

L Λ. VΠPO . i?RNAT\θ 14 disconnect the tool from its driving means in response to the tool being prevented from rotating.

11. An attachment according to any one of claims 1 to 9 in which the powered tool is a power post hole digger or auger.

12. An attachment substantially as hereinbefore described with reference to the accompanying drawings.