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Title:
CIRCULAR SAW DEVICE WITH FACE MILLING MODULE
Document Type and Number:
WIPO Patent Application WO/2019/203640
Kind Code:
A1
Abstract:
Circular saw device comprising a drive shaft, a hole saw and optionally a hole saw adapter for securing the hole saw to the drive shaft, the device also comprising an insert which is positioned in the hollow inner space of the hole saw and adapted during operation of the circular saw device to mill and remove the material of the workpiece between the circular saw cut, wherein the insert is a face mill comprising a central axis which at one outer end is engaged with the tool end of the drive shaft or with the hole saw adapter and which comprises at the other outer end one or more milling elements, which are mounted essentially perpendicular to the central axis and which extend radially from the central axis to the inner side of the cylindrical mantle.

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Inventors:
VAN DER KLIP EMIEL (NL)
DE GRAAF AREND (NL)
Application Number:
PCT/NL2019/050220
Publication Date:
October 24, 2019
Filing Date:
April 15, 2019
Export Citation:
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Assignee:
BOUWROB BV (NL)
International Classes:
B23B51/04; B23Q11/00; B28D1/04
Domestic Patent References:
WO2006062388A12006-06-15
WO2001038028A12001-05-31
WO2006122417A12006-11-23
Foreign References:
DE202013102491U12013-06-17
DE102006006445A12007-08-23
DE102006021715A12007-11-15
US4078622A1978-03-14
CH276789A1951-07-31
DE29519102U11996-01-25
DE8512910U11987-11-12
US5015128A1991-05-14
DE19712435A11998-10-01
DE102006006445A12007-08-23
DE202013102491U2013-06-11
EP0870561A11998-10-14
EP1827741A12007-09-05
NL2003834C22011-05-23
EP1555076A12005-07-20
NL1040196C22014-11-04
NL2013758B12016-10-06
NL2019036A2017-12-13
US3880546A1975-04-29
GB2257381A1993-01-13
DE202013006690U12013-08-07
US20090279972A12009-11-12
US20110255931A12011-10-20
NL2020770A2018-04-15
Attorney, Agent or Firm:
HUYGENS, Arthur (NL)
Download PDF:
Claims:
Claims

1. Circular saw device, comprising:

an arbor having a longitudinal body with a drive end and a tool end, a hole saw, comprising at least a partially hollow cylindrical or cup-shaped body with a bottom wall having an opening in its centre for mounting the hole saw to a hole saw adapter or directly to the arbor, wherein a cylindrical mantle is arranged essentially perpendicularly to the bottom wall, which together with the bottom wall defines a semi-open hollow space of the hole saw, wherein the cylindrical mantle at the peripheral edge is provided with a cutting edge with cutting elements for making a circular cut in a workpiece, and, optionally,

a hole saw adapter for securing the hole saw to the arbor,

characterised in that the circular saw device also comprises an insert which is positioned in the semi-open hollow space of the hole saw and is adapted during operation of the circular saw device to mill and remove the material of the workpiece between the circular saw cut.

2. Circular saw device according to claim 1 , wherein the insert is a face mill. 3. Circular saw device according to claim 1 or claim 2, wherein the insert comprises two or more milling elements, which are mounted on the central axis in a star shaped configuration, a configuration in the form of a cross, or in the form of a blade.

4. Circular saw device according any one of claims 1 to 3, wherein the insert is adjustable in height relative to the cutting edge of the cylindrical mantle of the hole saw.

5. Circular saw device according any one of claims 1 to 4, wherein the milling elements have a cutting angle in the range between 0 and 90 degrees relative to the material of the work piece to be removed.

6. Circular saw device according any one of claims 1 to 5, wherein the milling elements are straight or provided with saw teeth or sintered diamond.

7. Circular saw device according to any one of claims 1 to 6, wherein the insert is secured releasably in the inner space of the hole saw.

8. Circular saw device according to any one of claims 1 to 7, wherein the insert comprises a central longitudinal axis, the center line of which coincides with the center line of the arbor, wherein the central axis at one outer end is coupled with the tool end of the arbor and at the other outer end comprises one or more milling elements, which are arranged essentially perpendicular to the central axis and extend radially to the inner side of the cylindrical mantle.

9. Circular saw device according to any one of claims 1 to 7, wherein the insert at the radial outer ends of the milling elements is releasably secured to the inner wall of the cylindrical mantle of the hole saw.

10. Circular saw device according to claim 9, wherein multiple attachment elements are arranged at different heights on the inner wall of the cylindrical mantle, such that the insert is adjustable in height.

1 1. Circular saw device according to any one of claims 1 to 8, wherein the arbor comprises mounting means at the tool end for connecting the hole saw to the arbor, and wherein the tool end comprises an axial hole at the centre line of the arbor for housing the central axis of the insert.

12. Circular saw device according to any one of claims 1 to 8, wherein the arbor comprises mounting means at the tool end for connecting the hole saw adapter to the arbor, wherein the hole saw adapter comprises an axial hole at the centre line of the arbor for housing the central axis of the insert, and wherein the hole saw adapter comprises locking means for releasably securing the central axis of the insert at a desired height.

13. Circular saw device according to any one of claims 1 to 8, wherein the insert comprises a central axis with a tapered end, which is mounted in the axial direction in a corresponding central opening of the hole saw adapter or directly into the corresponding axial opening at the tool end of the arbor, wherein the milling elements at the other outer end of the central axis of the insert, are optionally releasably clamped at their radial outer ends against the interior wall of the cylindrical mantle.

14. Circular saw device according to any one of claims 1 to 13, wherein the insert is replaceable and the shape and the material of the insert to be used is adapted to the nature of the material to be removed from the workpiece.

15. Circular saw device according to any one of claims 1 to 14, wherein the plane of the milling elements of the insert is situated approximately 2-5 mm underneath the plane of the circumferential cutting edge or the cutting elements on the circumferential edge.

16. Circular saw device according to any one of claims 1 to 15, wherein the milling elements of the insert are positioned in the same plane as the circumferential cutting edge or the cutting elements on the circumferential edge.

17. Circular saw device according to any one of claims 1 to 16, wherein the hole saw adapter comprises coupling means for coupling to the hole saw, wherein the coupling means are hollow.

18. Circular saw device according to claim 17, wherein the coupling means are releasable coupling means, which for example comprise a threaded shaft or a bayonet fitting to engage with the correspondingly shaped hole saw.

19. Circular saw device according to claim 17 or claim 18, wherein the hollow coupling means are adapted for engaging with the arbor, for example by means of a threaded connection.

20. Circular saw device according to one of the preceding claims, wherein the hole saw adapter comprises coupling means for coupling with the hole saw, where the coupling means are hollow and comprise a surface that permits axial sliding of the arbor with the connected insert through the opening in the hole saw, wherein the hole saw adapter and the arbor are provided with means for rotatably and axially locking the arbor.

21. Circular saw device according to claim 20, wherein the axial locking means comprise:

first axial locking means, embodied by a latch, in particular a transverse latch, which is arranged on the hole saw adapter, and

second axial locking means, embodied by one or more notches, in particular transverse notches, which are arranged on the arbor.

22. Circular saw device according to claim 20, wherein the rotational locking means comprise:

first rotational locking means which are arranged on the hole saw adapter and embodied by the shape of the central hole in the hole saw adapter, and second rotational locking means, embodied by the exterior shape of the arbor which corresponds to the cross-section in such a way that the first and second locking means are mutually slidable,

wherein the shape of the cross-section and the corresponding exterior shape are such that in the rotationally locked situation mutual rotation is blocked.

23. Circular saw device according to any one of claims 1 to 22, wherein the circular saw device comprises an extraction device, wherein the bottom wall comprises one or more extraction holes

24. Circular saw device according to claim 17, wherein the extraction device partly extends across the cylindrical mantle of the hole saw in such a way that the edge of the extraction device forms an abutment for the circular saw device which enables determining the depth of the holes to be drilled.

25. Circular saw device in conjunction with a drilling jig for creating a cylindrical hole or a plurality of contiguous holes in a workpiece such as a partition wall or a wall for mounting a socket box or a plurality of contiguous socket boxes, wherein a circular saw device is applied as defined in any one of claims 1-14.

26. Releasable insert for a circular saw device, wherein the insert is a face mill as defined in any one of claims 1-25.

27. Releasable insert according to claim 26, wherein the insert forms an integral part with the arbor.

28. Releasable insert according to claim 25 or 26, wherein the arbor comprises one or more notches for axial locking in conjunction with a hole saw adapter as defined in claim 20 and claim 21 and wherein the arbor has an exterior shape such that it is suited for rotational locking in conjunction with a hole saw adapter as defined in claim 20 and claim 22.

29. A method for creating a cylindrical hole or a plurality of contiguous holes in a partition wall or a wall for mounting a socket box or multiple contiguous socket boxes, using a circular saw device and a drilling jig as defined in claim 19, wherein the exterior circumference of the circular saw device corresponds with the holes of the drilling jig, wherein the required holes are marked on the partition wall or on the wall using the drilling jig, after which the jig is immobilised in the correct position and the circular saw device is sequentially placed in the respective holes of the drilling jig and used to create holes to the required depth in the partition wall or wall. 30. The method according to claim 29, wherein the depth of the hole(s) to be drilled is predetermined by the length of the cylindrical mantle to the abutment which is formed by the edge of the extraction device, and the thickness of the drilling jig.

Description:
Circular saw device with face-milling module

The invention relates to a circular saw device, adapted for arranging a cylindrical hole or multiple contiguous cylindrical holes in a workpiece such as a partition wall or a wall, whereby the hole is meant for mounting a wall socket box or multiple contiguous wall socket boxes therein. The invention also relates to a method for creating one or more cylindrical holes in a workpiece and to a drilling jig applicable therein.

Circular saw devices for arranging round holes in a workpiece, such as a partition wall or a wall, for mounting cylindrical socket boxes are generally known and are usually designated by the term“hole saw”. The term“hole cutter” is also used. Both terms“hole saw” and“hole cutter”, as used in this description, are meant to be equivalent, while the term“circular saw device” refers to the assembly comprising the hole saw and possible accessories, as will be described hereinafter.

A circular saw device essentially comprises an arbor, also called a drive shaft or spindle, a hole saw (in the narrow sense of the word), and in most cases a hole saw adapter or flange for connecting the hole saw to the arbor. One outer end of the arbor is clamped in the chuck or mandrel of a driving means, such as a drilling machine, whereas the other outer end is connected to a hole saw adapter which is adapted for mounting a hole saw thereto. Optionally a pilot drill is mounted in the hole saw adapter to direct the hole saw. In certain embodiments the hole saw adapter is provided with a through hole, through which the arbor can pass. In such cases the hole saw adapter can be moved over the arbor and is releasably attached thereto. The optional pilot drill is then mounted in the axial outer end of the arbor.

The hole saw comprises an at least partially hollow cylindrical or cup-shaped body with a bottom wall having generally an opening in the centre for connecting the hole saw to the hole saw adapter or directly to the arbor. Internal thread can be applied to this opening, thread with which the hole saw can be screwed onto the hole saw adapter or the arbor. The hole saw adapter can also be connected to the hole saw in a different way, for example by using screws or a welded connection. A cylindrical mantle is attached essentially perpendicularly to the bottom wall, and comprises a cutting edge at the outer end thereof. The cutting edge comprises for example saw teeth or sintered diamond or heat resistant tungsten carbide teeth soldered onto the edge, or the like, as is common knowledge for a person skilled in the art. A typical example of a circular saw device according to the state of the art, comprising a hole saw which is mounted on a arbor by means of a hole saw adapter, as well as a pilot drill, is represented in Figure 7.

Hole saws are commercially available in different sizes and for different materials, such as wood, stone, and metal.

To install socket boxes for electrical installations in a brick or concrete wall, or in a wall made up of plaster boards, cellular concrete blocks, or limestone blocks, one saws a hole with a predefined depth, depending on the type of socket box, but usually about 30 mm to about 50 mm, using a circular saw device. The diameter of the hole amounts to approximately 82 mm in the Netherlands for a single standard socket box. The centre of the hole is precisely marked, after which the circular saw device, usually equipped with a pilot drill, is used to saw the circumference of the hole to the required depth.

A drawback of the conventional circular saw devices is that in relatively soft materials, such as gypsum blocks and cellular concrete blocks, as well as in hard materials, such as stone and concrete, only the contours of the required holes can be sawn instead of the overall hole. The intermediate part has to be removed subsequently, for example with a chisel. This is time-consuming and implies that the bottom of the hole shall never eventually be completely flat. Moreover, when using this method for creating such a hole the risk exists, particularly with a usual wall thickness of 70 mm, that the wall surface on the other side is damaged, which would imply relatively expensive repair works. The use of a pilot drill even increases the risk of damage to the wall surface on the other side.

In recent years this problem has been recognised in the professional world, and solutions have been proposed without however having led to the development of commercially available hole saws that really would mean an improvement with regard to this aspect.

German Offenlegungsschrift DE 10 2006 006 445 A1 discloses a device for drilling a hole in a workpiece, more particularly for drilling a hole with a diameter of more than 25 mm, and even more particularly with a diameter of more than 50 mm, wherein the device comprises an at least partially hollow cylindrical carrier to which one or more cutting edges are connected which are directed toward the workpiece. The cutting edges form an angle with an arbor, and are more particularly perpendicularly orientated relative to the arbor, radially from the outer side to a central point on the drilling axis of the device. The tool is either used as a cylindrical module on a conventional hole saw, or forms an integral part with the saw. The device is predominantly suited to drilling in relatively soft materials, such as gypsum blocks and cellular concrete blocks.

A drawback of the tool described in this document is that the cutting effect is determined by the radial cutting edges, which are located at the front end of the tool. The cutting direction is only indicated by a pilot pin, which implies that the tool can only be manipulated with some difficulty due to the large resistance and that the whole assembly will become unstable, more specifically when working with harder materials.

German utility model DE 2013 102491 U1 discloses a hole saw for arranging holes in insulating building material, for example foamed synthetic materials such as polystyrene. The hole saw comprises a rotatably driven cylindrical cup- or bowl-shaped tool comprising a cutting edge at the front open end of the cylindrical wall, while at least one additional milling element is foreseen in the hollow space which is delimited by the cutting edge and the cylindrical wall. This additional milling element crosses the hollow space transversely and extends radially from the inner side of the wall to the central axis, preferably in a straight line to the other side of the interior wall. According to this document the cutting edge of the cylindrical wall and the cutting edges of the radial milling element are preferably situated in the same plane. A pilot drill determines the sawing direction. In addition, the bottom wall comprises holes through which material can be expelled or extracted.

The hole saw described here suffers from the same drawback in that the cutting edges of the circumference and the radial milling element are situated in the same plane. This also explains why this hole saw is only suitable for soft materials such as polystyrene.

European patent application EP 0 870 561 A discloses a drill of the hole saw type, which is particularly suited to working with wood, wherein inside the drill head an insert is provided in the form of a milling drill bit, of which the cutting edges which are directed towards the front end are recessed relative to the cutting edge of the drill head. The drilled or milled material thus remains in the interior space of the saw device and will not be expelled or extracted.

Dutch patent specification NL 2016300 discloses a circular sawing device with a pair of saw blades arranged in concentric spaced relationship for producing concentric cuts in a piece of work, in particular in plasterboard, and material removing pins arranged between the blades for removing material from the piece of work between the cuts produced by the saw blades. Thus, a circular groove is created.

Reading through the patent literature, it appears that the attention and efforts have mainly been concentrated on the improvement of the connecting systems between a hole saw and an arbor. In EP 1827741 (= WO 2006/062388) a quick-change arbor is disclosed for an apparatus, and more specifically a hole saw, comprising: an arbor comprising a longitudinal body with a driving end and a tool end, a hole saw adapter for connecting the arbor to a hole saw, wherein the adapter is slidably removable from the arbor, and wherein the adapter comprises a central hole which permits the sliding movement of the adapter over the arbor, as well as means for rotatably and axially locking the adapter on the arbor, wherein the axial locking can be activated by a pivoting transverse latch on the adapter, wherein the latch engages with a recess on the arbor, and in which the rotational lock can be realised by using the external contours of the longitudinal axis and the form of the cross section of the central hole of the adapter, forms that mutually correspond in such a way that they can be slidably moved with respect to one another. The driving end of the arbor is preferably a hexagonal element with an outer end that can be connected to a drilling machine. In the corresponding case, the central hole of the adapter also comprises a hexagonal form, in such a way that the arbor can be axially inserted into and through the central hole of the adapter, after which the adapter can be locked into place by inserting the latch into the recess of the arbor. The arbor comprises an axial hole for a pilot drill at the tool end.

Dutch patent specification NL 2003834 discloses a simplified embodiment of this system in which only part of the hole saw adapter is mounted on the hole saw.

A typical example of a quick-change arbor according to the state of the art in combination with a conventional hole saw and a pilot drill, as described in EP 1827741 , is represented in Figure 12.

Other examples of change systems are disclosed in, e.g., EP 1555076, NL 1040196, NL 2013758, NL 2019036, US 3,880,546, GB 2,257,381 , DE 20 2013 006 690 U1 , US 2009/0279972, US 2011/0255931 , WO 2001/038028, and WO 2006/122417.

An object of the invention is to provide an improved circular saw device without using a pilot drill, which is adapted to accurately arrange holes in partition walls or walls for mounting socket boxes, which not only saws the contours of the holes but also simultaneously mills away and removes the material of the complete hole.

It has now been found that this object can be achieved by a circular saw device with the characteristics of claim 1 .

The circular saw according to the invention is in principle suitable for any material in which socket boxes are to be mounted, including harder types of stone, such as brick and concrete. However, the saw device is preferably used on softer materials, such as plaster blocks and cellular concrete blocks. By using a circular saw device according to the invention without pilot drill on a workpiece, the backside of the workpiece and the material close to the backside remain untouched and unchanged with respect to appearance, colour, structure, and strength.

The insert according to the invention is a face mill, also referred to as facing cutter or face milling cutter, which is provided with one or more milling elements. The number of milling elements is essential for the invention, but will usually be between two and eight, and is preferably four, five, or six. The milling elements are for example mounted on the central axis in a star-shaped arrangement, a configuration in the form of cross, or in the form of a blade. The milling elements of the insert preferably have a cutting angle of between 0 and 90 degrees with respect to the material of the workpiece that has to be removed. The cutting elements can for example be straight or provided with saw teeth or a small layer of sintered diamond.

The insert according to the invention preferably is adjustable in height relative to the cutting edge of the cylindrical mantle of the hole saw.

According to an embodiment of the invention the insert comprises a central longitudinal axis, the center line of which coincides with the center line of the arbor, wherein the central axis at one outer end is coupled with the tool end of the arbor and at the other outer end comprises one or more milling elements, which are arranged essentially perpendicular to the central axis and extend radially to the inner side of the cylindrical mantle. The milling elements are for example mounted on the central axis in a star-shaped arrangement, a configuration in the form of cross, or in the form of a blade. According to an embodiment of the invention the arbor comprises mounting means at the tool end for connecting the hole saw to the arbor, whereas the tool end comprises an axial hole for housing the central axis of the insert.

According to another embodiment of the invention the arbor comprises mounting means at the tool end for connecting the hole saw adapter to the arbor, wherein the hole saw adapter comprises an axial hole at the centre line of the arbor for housing the central axis of the insert.

According to yet another embodiment of the invention the insert comprises a central axis with a tapered end, which can be mounted in the axial direction in a corresponding central opening of the hole saw adapter or directly in the corresponding axial opening at the tool end of the arbor, an opening that until now was only destined and used for a pilot drill. In a certain embodiment, the milling elements at the other outer end of the central axis of the insert, which radially extend from the axis to the inner side of the cylindrical mantle, can be releasably clamped against the cylindrical mantle.

The insert according to the invention is preferably releasably arranged in the interior space. This offers the advantage that the interior space of the saw device can be cleaned after the insert has been removed and that the milling elements of the removed insert can be easily honed and sharpened. If the central axis of the insert comprises a tapered end with which the axis is clamped in the axial end of the arbor of the hole saw adapter, it can be removed in the same way as has been the case until now for a pilot drill, as is known by the person skilled in the art. Furthermore, the insert is preferably replaceable, and ideally the form and the material of the insert and more specifically of the milling elements to be used can be adapted to the nature of the material to be removed from the workpiece.

According to an embodiment of the invention the plane of the milling elements of the insert is situated approximately 2 to 5 mm underneath the plane of the circumferential cutting edge or the cutting elements, which means that the circular saw device has an increased stability when applied to a workpiece during the cutting operation. The cutting elements of the insert can however also be positioned in the same plane as the circumferential cutting edge or the cutting elements, more specifically when a drilling jig is used as described in the priority application NL 2020770. According to yet another embodiment the insert can also be permanently arranged in the hollow space of the hole saw, for example by welding or soldering the radial ends of the insert to the inner side of the cylindrical mantle. This embodiment is more specifically suited to drilling in very hard types of stone or in concrete.

According to yet another embodiment the hole saw adapter comprises coupling means to form a connection with the hole saw, wherein the coupling means are hollow. The coupling means are preferably removable coupling means which for example comprise a threaded shaft or a bayonet fitting to form a connection with the correspondingly shaped hole saw. In a specific embodiment the hollow coupling means are suitable for engaging with the arbor, for example by means of a threaded connection.

According to yet another embodiment the hole saw adapter comprises coupling means to form a connection with the hole saw, wherein the coupling means are hollow. The axial tool end of the arbor is also hollow for housing the central axis of a flat-mill which can be slidably moved in the hollow interior of the hole saw and locked on the hole saw adapter by means of a locking screw.

According to a preferred embodiment of the invention the hole saw adapter comprises coupling means for forming a connection with the hole saw, where the coupling means are hollow and comprise a surface that permits an axial sliding movement of the arbor with the connected insert through the opening in the hole saw, wherein the hole saw adapter and the arbor comprise means for rotatably and axially locking the arbor.

In this embodiment the insert with its central axis is directly coupled with the arbor which connects the circular saw device of the invention to a drilling machine. Preferably, the insert forms one integral part with the arbor. The arbor can be part of a quick-change tool for the circular saw device, as is described in EP 1827741 and NL 2003834.

The axial locking means comprise first axial locking means in the form of a latch, more specifically a transverse latch, arranged on the hole saw adapter, as well as second axial locking means in the form of one or more notches, more specifically transverse notches, arranged on the arbor. A manually activated latch is preferably used, more specifically a spring loaded radial latch. The multiple notches in the arbor for axially locking the hole saw adapter allow the cutting edge of the cylindrical mantle to be adjusted at different positions with respect to the cutting edge of the insert. The number of notches for the axial locking is preferably two, three, or four. The cutting edge of the cylindrical mantle can therefore, in a first locking position of the hole saw adapter, be positioned at the maximum distance with respect to the cutting edge of the insert, which means that the contours of the hole can be drilled without experiencing resistance generated by the insert. Subsequently, the adapter can be placed in a second locking position in which the cutting edge of the insert is positioned for example a few millimetres underneath the plane of the cutting edge of the cylindrical mantle, and the complete hole can then be drilled in a perfectly stable way. Eventually, the adapter can be placed in a subsequent position, in such a way that the cutting edge of the insert and the cutting edge of the cylindrical mantle are situated in the same plane or even beyond the latter, which means that the bottom of the drilled hole can be cleaned and flattened. These multiple notches also permit one to adapt the insert to the different sums of the lengths of the cylindrical mantle and the cutting elements or cutting teeth that are attached to the latter in different embodiments of hole saws.

The rotational locking means comprise first rotational locking means arranged on the hole saw adapter, and can practically be the form of the central hole in the hole saw adapter, as well as second rotational locking means in the form of the exterior form of the arbor that corresponds to the cross-section in such a way that the first and second locking means can carry out a mutual sliding displacement, in which the form of the cross-section and the corresponding exterior form are such that in the rotationally locked situation a mutual rotation is made impossible. An exterior form that is very well suited is for example the hexagonal form.

The design and construction of the circular saw device with quick-coupler that is mounted on the arbor are substantially the same as the design and construction that are disclosed in EP 1827741 , as described above, with the proviso that the pilot drill has been replaced by the insert according to the invention and that the insert can be adjusted on the arbor at different positions using the multiple notches. The description of EP 1827741 is therefore considered to be integrally incorporated herein by reference.

A system for reieasabiy coupling a hole saw to a drill arbor can also be used, as described in NL 2013758, wherein the pilot drill (24) is replaced by the insert according to the invention.

The insert according to the invention, including the milling elements, is preferably made of a strong and hard type of steel, such as high-speed steel (HSS). The milling elements of the insert can be straight or provided with saw teeth or sintered diamond. For soft materials, an insert of suitable plastic material or an insert made of a softer steel can be applied, if desired.

The circular saw device according to the invention preferably comprises an extraction device for removing dust and debris during the drilling operation. Such extraction devices are well known in the art for conventional circular saw devices and will therefore not be described in detail here. When using an extraction device, the bottom wall of the hole saw preferably comprises one or more extraction holes. In a preferred embodiment the extraction device is arranged around the cylindrical mantle in such a way that the edge of the extraction device forms an abutment for the circular saw device according to the invention, which is useful in determining the depth of the holes to be drilled.

The circular saw device according to the invention is preferably used in combination with a drilling jig, as is described in Dutch priority application NL 2020770. Since no pilot drill is used when applying the saw device according to the invention, as described above, and considerable and irregular lateral forces may occur when drilling in both soft and hard materials, there is a risk that the saw does not adequately stay in place. The above described drilling jig is an excellent solution to this problem.

The drilling jig therefore comprises a plate with two or more contiguous holes with the same diameter, whereby the circumference of a hole preferably responds to the exterior diameter of a hole saw. The diameter of the drilling jig can also be a few millimetres larger than the exterior diameter of the hole saw, in such a way as to make the drill suitable for hole saws of which the cutting teeth are slightly thicker, which would mean that the circumference of the hole saw can vary. The number of holes foreseen in the drilling jig can vary, but a drilling jig with two to five contiguous holes is preferred. The plate is preferably elongated and comprises along the circumference centering slots corresponding to the centre line dimensions of the holes.

The plate needs to be sufficiently thick to resist the lateral forces that can be generated by the saw device. The plate can be made from different materials, as will be obvious to a person skilled in the art. The plate is preferably made from plastic or metal, but other more environmentally friendly materials, such as wood, are also possible. The plate thickness can effectively be adapted to the desired drilling depth, whereby the extraction device that is preferably arranged on the circular saw device can serve as an abutment. The thickness of the plate preferably varies from about 5 mm to about 30 mm. The plate can also comprise fixing means, for example one or more holes, for temporarily fixing the plate onto the partition wall or wall.

The present invention also relates to a releasable insert for a circular saw device according to the invention, as described herein. The insert preferably forms an integral part with the arbor. The arbor preferably comprises one or more notches for an axial locking effect in combination with a hole saw adapter, and presents an exterior form in such a way as to make it suitable for a rotational locking action in combination with a hole saw adapter, as described herein.

The invention also relates to a method for arranging a cylindrical hole or multiple contiguous holes in a partition wall or in a wall for mounting a socket box or multiple contiguous socket boxes, using a circular saw device and a drilling jig according to the invention, wherein the exterior circumference of the circular saw device completely or substantially completely corresponds to the holes of the drilling jig, wherein the required holes can be marked on the partition wall or on the wall using the drilling jig, after which the jig is immobilised in the correct position and the circular saw device is sequentially placed in the respective holes of the drilling jig and used to create holes to the required depth in the partition wall or wall.

In a preferred embodiment the depth of the ho!e(s) to be drilled is predetermined by the length of the drill shaft to the abutment formed by the edge of the extraction device and the thickness of the drilling jig. In particular, the thickness of the drilling jig can be easily varied, so that holes of different depths can be drilled by drilling with the circular sawing device according to the invention until the abutment touches the drilling jig.

In another embodiment the height of the insert is varied during the drilling, whereby the cutting edge of the insert is initially recessed with respect to the cutting edge of the circumferential wall of the hole saw and the cutting edge of the insert, optionally by one or more intermediate steps, eventually comes to lie in the same plane as the cutting edge of the circumferential wall of the hole saw.

The invention will now be described and explained in more detail with reference to the accompanying drawings. Here, Figures 1-6 and 13-17 show a circular saw device and parts and components thereof according to the invention, Figures 7-10 and 12 show a circular saw device and parts and components thereof according to the state of the art, and Figure 11 shows a drilling jig as a useful aid when using the circular saw device according to the invention.

Figure 1 shows a circular saw device according to the invention in an embodiment with an extraction device;

Figure 2 shows a detailed representation of the insert in the hollow interior space of the circular saw device from Figure 1 ;

Figure 3 shows an exploded perspective view of a hole saw with an insert according to the invention;

Figure 4 shows a detailed representation of an alternative embodiment of a circular saw device according to the invention;

Figures 5A and 5B show two schematic drawings of an insert according to the invention, respectively in cross-section and in bottom view;

Figures 6A and 6B show two representations of an insert according to the invention;

Figure 7 shows a commercially available hole saw with pilot drill and arbor according to the state of the art;

Figure 8 shows a top view of a hole saw according to the state of the art;

Figure 9 shows an arbor according to the state of the art;

Figure 10 shows an arbor with a hole saw adapter and pilot drill according to the state of the art;

Figures 1 1 A and 11 B show a drilling jig according to the invention, with three contiguous holes, respectively in perspective and in top view;

Figure 12 shows a quick-change system for a hole saw according to the state of the art;

Figure 13 shows an alternative embodiment of an arbor with integrated insert according to a preferred embodiment of the invention; Figures 14A and 14B show a preferred embodiment of a circular saw device according to the invention with an arbor and an integrated insert, respectively, in frontal and rear view.

It is noted that the same reference numbers in the different figures refer to the same elements, sometimes shown in a different perspective. In Figure 12, the original reference numbers have been maintained as used in EP 1827741.

Figures 1 and 2 show a circular saw device (1) according to the invention, with a hole saw (1A) with a bottom wall (8) in which an opening (16) is arranged for mounting the hole saw (1A) on an arbor (6), as well as a cylindrical mantle wall (2), with a cutting edge with cutting elements (3). In the hollow space of the hole saw (1A) that is delimited by the cylindrical mantle wall (2), an insert (4) is arranged. The insert (4), which can be seen in more detail in Figure 6A and in Figure 6B, comprises a central axis (13) with a tapered end (25) (not visible) and cutting elements (5) that extend radially from the central axis to the inner side of the cylindrical mantle wall (2). The insert (4) in this embodiment is clamped fittingly with the tapered end (25) positioned in the axial end (6B) of the arbor (6) (not visible) on which the hole saw (1A) is mounted, in an identical way to conventional hole saws equipped with a pilot drill. The cutting elements (5) comprise at the axial end, distal with respect to the central axis, cutting edges with which the material of the workpiece can be milled away. The cutting elements present such dimensions that the insert, upon being mounted in the hollow interior space (12) of the hole saw (1A) that is delimited by the cylindrical mantle wall (2), is pressed against the inner wall of the cylindrical mantle wall (2) with the radial ends. The insert (4) can be removed, for example by tapping, for honing and grinding or for replacement, and in such a way that the hollow space (12) of the hole saw (1A) can be cleaned. The circular saw device (1) comprises an arbor (6) that can be mounted on a drilling machine as a driving unit by means of the free end (6A). The circular saw device (1) in this embodiment is equipped with a conventional extraction device (7) that comprises an abutment (11). To facilitate the extraction of debris, the bottom wall (8) of the hole saw (1A) in this embodiment is equipped with extraction holes (15). The abutment (11) can, for example in combination with a drilling jig (20) with a pre-determined thickness, be used to accurately determine the maximum depth of a hole to be drilled.

Figure 3 shows further details of a circular saw device according to the invention. This device comprises a hole saw (1A) with a bottom wall (8) and an adapter (9) with internal thread, screwed onto the end of the arbor (6) on which external thread (10) is arranged. A cylindrical mantle wall (2) extends from the bottom wall (8), with a cutting edge (3) at the free end thereof, with multiple individual cutting elements. An insert (4) is arranged in the hollow space (12) of the hole saw, whereby the central axis (13) of the insert is releasably mounted in the end of the arbor (6) at the free end thereof. Mounting the insert (4) in the arbor (6) is preferably carried out by means of a tapered clamping connection. However, any other suitable method can also be used for this purpose, as will be evident to a person skilled in the art. In the embodiment in Figure 3, the radial ends of the insert (4) are not connected with the interior wall of the cylindrical mantle.

In Figure 4 a heavier embodiment of a circular saw device (1) according to the invention is shown which is more suitable for hard materials, such as hard types of stone and concrete. The hole saw (1A) is made of thick cast steel with a thickness of 5 mm, wherein the insert (4) is welded at the radial ends to the cylindrical mantle (2), while the cutting edges (3.1 , 5.1) of the cylindrical mantle wall (2), respectively of the insert (4) are rougher than usual in order to avoid excessive wear.

Figures 5A and 5B show schematic drawings of the construction of the circular saw device (1), with two different embodiments of an insert (4) in side and bottom view. Figure 5A shows the construction of the insert with the milling elements (5) in the form of a blade, and with the central axis (13) with its tapered end (25) clamped fittingly in the axial end of the arbor (6). In the embodiment that is represented in Figure 5B, the milling elements (5) have been drawn in cruciform. Moreover, in the bottom view extraction holes (15) can be seen in the bottom wall (8).

As a comparison, Figures 7 to 10 show circular saw devices and individual parts and components thereof according to the state of the art. Figure 7 shows a commercially available bowl drill (Wolfcraft®) with the arbor (6) and a releasable and removable pilot drill (17).

In Figure 8 the bottom wall (8) of a hole saw (1 A) can be seen, with an internally threaded hole (16) arranged therein at the centre line for mounting the hole saw (1A) of an arbor (6) of a hole saw adapter (9). The arbor (6) and the adapter (9) are not represented in this figure.

The arbor (6) in Figure 9 comprises a driving end (6A) and a tool end (6B). The driving end (6A) can be connected to a drilling machine that is foreseen for driving the saw device. The tool end (6B) comprises external thread (16) onto which a hole saw (1A), a hole saw adapter (9), or a dust extraction adapter can be screwed. The axial tool end (6B) comprises a hole for mounting the pilot drill (17) or an insert (4) according to the invention.

Figure 10 shows a hole saw adapter (9) which on one side is mounted on an arbor (6), and on the other side on the centre line is provided with an axial opening into which a pilot drill (17) is inserted. The adapter (9) further comprises external thread (14) onto which a hole saw (1A) can be screwed. Instead of a pilot drill (17), an insert (4) according to the invention can be inserted into the axial opening of the adapter (9).

Figures 11A and 11 B show a drilling jig (20) which in this embodiment comprises a rectangular plate (21) and three contiguous holes (22). The plate (21) is preferably made from a suitable plastic, as is known by a person skilled in the art. However, it can also be made of other materials, such as plywood or metal. The drilling jig comprises centering slots (23) and fixing means (24) for an accurate marking of the drilling holes. The thickness of the plate can vary, but is preferably at least 10 mm.

Figure 12 shows a quick-change system for a hole saw, as described in EP 1827741. To avoid confusion, the Figure has been copied integrally, including the reference numbers, which hereinafter will be mentioned in bold.

The quick-change system comprises an arbor 3 with a drive end 4 and a tool end 5. The drive end 4 can be connected to driving means, such as a drilling machine. At the tool end 5 an axial hole is arranged into which a pilot drill 14 can be inserted. The drive end 15 of the pilot drill 14, and the tool end 5 of the arbor 3 both comprise corresponding means to attach the pilot drill 14 and to release it. These means can for example be a bayonet fitting, certain clamping means, or a threaded connection.

The quick-change system further comprises a hole saw adapter 6 to which the hole saw 2 can be connected by means of coupling means 11 -1 and 11 -2. The hole saw adapter 6 comprises a central hole 7 through which the arbor 3 with the pilot drill 14 can be slidingly inserted.

The quick-change system further comprises means for rotatingly (8; 8-1 , 8-2) and axially (9; 9-1 , 9-2) locking the hole saw adapter 6 onto the arbor 3. The first rotation locking means 8-1 are arranged on the hole saw adapter 6, and are realised by the form of the cross-section of the central hole in the hole saw adapter 6. The second rotation locking means 8-2 are realised by the exterior form of the arbor 3, a form that corresponds in such a way to the cross-section that the first and second rotation locking means can be slidingly moved with respect to one another. The form of the cross-section and the corresponding external form are such that in a rotatingly locked situation the mutual rotation of the parts or components is blocked. The axial locking means 9 comprises first axial locking means 9-1 , realised by a latch, more specifically a transverse latch, arranged on the hole saw adapter 6, as well as second axial locking means, realised by a recess, more specifically a transverse recess, arranged on the arbor 3, for inserting the latch 9-1 to be locked therein.

Figure 13 shows an arbor with an integrated insert (26), wherein the arbor can be used in a preferred embodiment of a circular saw device according to the invention, as represented in Figures 14A and 14B. The arbor with integrated insert (26) is suitable for insertion into a hole saw, and comprises an arbor (6) with a drive end (6A) and a tool end (6B), whereby milling elements (5) are arranged substantially perpendicularly with respect to the arbor (6) at the tool end, in which the milling elements extend radially from the arbor (6) to the interior wall of the hole saw. The arbor (6) comprises a form that is suitable for use in combination with an appropriate hole saw adapter (28) to create a rotation locking mechanism, in a way that is similar to the one described with reference to and shown in Figure 12. A suitable external form of the arbor can for example be hexagonal. The arbor (6) comprises multiple recesses (27A, 27B, 27C), more particularly transverse recesses that are suitable for axially locking the arbor in combination with locking means (19), such as a latch, more particularly a transverse latch, arranged on a suitable hole saw adapter (28), in a similar way to the one described with reference to and illustrated in Figure 12.

In an alternative embodiment (not represented) an arbor (6) is used that is similar to the arbor 3 in Figure 12, with an insert (4) according to the invention attached thereto. The connection of the insert (4) to the arbor (6) takes place in the same way as the connection of the pilot drill 14 to the arbor 3, as illustrated in and described with reference to Figure 12.

The arbor with the integrated insert (26) or an arbor (6) with the insert (4) mounted in the latter is inserted into the hollow space (12) of a hole saw on which a hole saw adapter (28) with a latch mechanism (19) is mounted, and passed through the central hole of the bottom wall of the hole saw and the hole saw adapter, after which the arbor (6) is axially fixed onto the arbor by means of the latch mechanism (19) of the hole saw adapter (28) and one of the recesses (27A, 27B, 210) . The hole saw adapter (28) with the latch mechanism (19), together with the arbor (6) with the recesses (27A, 27B, 27C) form a quick-change system of the type that has been described with reference to and illustrated in Figure 12. After mounting and rotationally and axially locking the arbor with the insert into the hole saw, the arbor can be connected at the drive end (6A) to driving means, such as the chuck or the mandrel of a drilling machine, after which the circular saw device according to the invention is ready for use.

Figures 14A and 14B show the construction of a preferred embodiment of a circular saw device according to the invention, with a quick-change system as described above. A hexagonal arbor with the integrated insert (26) of a hexagonal arbor (6) with the insert (4) mounted therein, is arranged in the hollow space (12) of a hole saw 1A, and passed through the central hole (8) of the bottom wall of the hole saw and the corresponding hexagonal central hole of the hole saw adapter (28) that is mounted on the hole saw, whereby the hole saw is rotationally locked onto the arbor. The arbor is further passed through the hole saw adapter (28) until the latch that is connected to the activating element (19) is lodged in a recess (27) of the arbor and the hole saw (1A) is axially locked onto the arbor. The activating element (19) and the latch preferably form an integrated part and comprise a hinged pin and a compression spring, as described with reference to and illustrated in Figure 12, in such a way that the latch is pushed into the recess by the spring force, and the hole saw is axially locked onto the arbor. By pressing the activating element against the spring force the latch is pushed out of the recess thereby unlocking the hole saw. The hole saw can subsequently be slid over the arbor and then locked into one, if present, of the subsequent recesses on the arbor. Thus, the insert can be efficiently mounted in and removed from the chuck, the latter for being able to clean the internal space of the hole saw and to replace or repair the insert. This way, the milling elements (5) of the insert can also be set in different positions with respect to the cutting edge (3) of the cylindrical mantle wall (2) of the hole saw (1A).

It is preferred that the insert be mounted in such a way in a first position at the beginning of the drilling of a hole in a partition wall or a wall by means of the circular saw device and - preferably - the drilling jig according to the invention, that the plane of the milling elements of the insert is recessed with respect to the cutting edge of the cylindrical mantle wall of the hole saw. In this way a stable cut of the contours of the hole can be created before the intermediate part is milled away and the resistance of the saw device increases. After the contours of the hole have been sufficiently sawn, for example to a depth of 25 mm to 30 mm, the insert can be placed in a second position with respect to the cutting edge (3) by using the activating element (19), whereby the plane of the milling elements of the insert approaches the cutting edge (3). Once the desired depth of the hole is reached or substantially reached, the insert can be placed in a third position with respect to the cutting edge (3), whereby the plane of the milling elements of the insert for example is brought to the position of the plane of the cutting edge (3) or even slightly higher should this be required. This way, the bottom of the hole can be milled evenly and flat which means that a uniform and accurate hole can be created. The hole saw according to Figures 14A and 14B optionally comprises extraction holes (15) in the bottom wall (8) if the circular saw device of which the hole saw is part comprises an extraction device and extraction slits (18) in the cylindrical mantle wall (2).

It will be clear to a person skilled in the art that modifications and adaptations can be carried out with regard to the method and device described in this application without departing from the essential idea of the invention. These modifications and adaptations are therefore deemed to fall within the scope of protection of this invention as described by the appended claims.

Reference list

1. circular saw device according to the invention

1A. hole saw (in the narrow sense)

2. cylindrical mantle of the hole saw (1 A)

3. cutting edge of the cylindrical mantle (2) with cutting elements or cutting teeth

4. insert (face mill) with central axis (13) and milling elements

5. milling elements of the insert (4)

6. arbor with a drive end (6A) and a tool end (6B)

7. dust extraction device

8. bottom wall of the hole saw (1A)

9. hole saw adapter

10. thread of the arbor (6) at the tool end (6B)

11. abutment of the dust extraction device (7)

12. hollow interior space of the hole saw (1 A)

13. central axis of the insert (4)

14. thread of the hole saw adapter (9) for mounting the hole saw (1 A)

15. extraction holes in the bottom wall (8) for extraction device (7)

16. central hole in the bottom wall (8)

17. pilot drill

18. extraction holes or slits in the cylindrical mantle (2) 19. latch mechanism for locking the hole saw adapter (28)

20. drilling jig according to the invention

21. flat plate of the drilling jig (20)

22. contiguous holes of the drilling jig

23. centering slots of the drilling jig (20)

24. mounting holes of the drilling jig

25. tapered end of the central axis (13) of the insert (4)

26. drive shaft with integrated insert

27A, 27B, 27C. notches in the drive shaft (26)

28. hole saw adapter, suitable for rotational and axial locking of the drive shaft (6)

29. locking screw for the central axis (13) of a face mill

30A, 30B, 30C. U-shaped supports for mounting a face mill to the cylindrical mantle of a hole saw at different heights.