GB2330794A

GB2330794A - Woodworking router with replaceable blades.

Info

Publication number: GB2330794A
Application number: GB9823072A
Authority: GB
Inventors: Reichenthal Miklos
Original assignee: Dimar Ltd
Current assignee: Dimar Ltd
Priority date: 1997-10-28
Filing date: 1998-10-21
Publication date: 1999-05-05
Also published as: GB9823072D0; DE19849592A1; IL122044A0

Abstract

A router comprises a body (4), made of metal, which has a shaft (1) at one end. The router is installed in an automated machine by means of the shaft. Adjacent the shaft, a blade support (7) is located and this supports a blade (5). Thus, the blade is prevented from sliding inside a blade groove (9). The blade groove (9) is carved inside the router body, along its longitudinal surface, and it holds the blade (5). The blade is secured inside the groove by means of a screw (8) which is screwed into a bore in the rod. The screw thus presses against the blade frontal plane holding it in place against the wall of the groove behind it.

Description

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FIELD OF THE INVENTION

2330794 The present invention relates to woodworking. More particularly it relates to a router for woodworking with replaceable blades.

BACKGROUND OF THE INVENTION

When processing wood, in the manufacture of furniture, the use of a router is sometimes required. A router is a rotating toot vMh a blade or several blades attached to it, which is guided through the wood being processed, automatically or manually, to produce a groove or an edge of a predetermined profile.

There are two types of routers. One type of routers is characterized by the fact that the blades are welded to the router's body. This feature renders the toot extra strength, due to the fact that the blades are tightly attached to the router, but when a blade breaks the whole router needs to be replaced.

In the other type of routers the blades are replaceable. This feature ensures prolonged use of the router, and lower maintenance costs, as only the blades need replacement. The blade is placed inside a longitudinal groove in the router main body, so that the cutting edge of the blade sticks out of the groove, and can be employed on the wood.

There are two common methods for attaching and fastening the blades in place inside the router's groove. One way is to drill holes in the blade and fasten it to its position inside the groove by screws passed through the holes and tightened to the side wall of the groove. This method has as drawbacks. Holes drilled in the blades limit the possibility of reducing the dimensions of the blade to very small dimensions, and indeed this kind of blades is usually used in routers of relatively larger sizes. Blades with holes in them are also more vulnerable and can break easily, and therefore need frequent replacing. Another commonly used method is to. lock the,bfade, which has no holes in it, in place, by tightening screws pressing against the blade body, and forcing it to remain stationary. A blade commercially available is usually made of some kind of a hard metal, and features a polar symmetry, to enable double use. The blade usually has a narrow elongated body, and its two elongated sides are sharpened to present cutting edgos (one side is used at a time, and when it becomes blunt the blade is turned to present the other sharp cutting edge). The frontal plane of the blade is well sharpened in order to provide quality woodworking, as it is this plane that comes in contact with the prom wood and performs the cutting. The cross section of the blade in its width presents a trapezium-like shape, as the frontal plane of the blade is larger than its back plane. This is so because the two elongated sides of the blade present a wedge. The inclining plane at the back of the blade is referred to as the releasing back. The blade's hook angle determines the quality of woodworking and the durability of the blade. In known routers with replaceable blades, where no holes are drilled in the blade, the blade is fastened in place by a screw pressind against the back of the blade, pushing it forward to the groove wall in front. It should be noted that the blade could be positioned radialty in respect to the center of the router, but also off-radially, in order to obtain a greater hookangle of the blade's edge. This 3 means that fastening the screws onto the backside of the blade renders the device vulnerability, as the screws have shorter screwing bores in which they are screwed into.

It is the object of the present invention to provide a router with replaceable blades for wood processing which is more durable and strong.

BRIEF DESCRIPTION OF THE INVENTION

The router for woodworking with replaceable blades, of the present invention comprises a rod having at least one groove along its longitudinal surface, and at least one blade, inserted inside said groove, so that the cutting edge of said blade sticks out of the groove to present a predetermined hook angle, wherein said blade is secured in place inside the groove by means of at least one screw, screwed through a bore in the rod, having matching internal screw thread, directed at said blade frontal plane, so that the screw presses against said blade frontal plane, forcing the blade back against the groove wall behind a.

4 BRIEF DESCRIPTION OF THE FIGURES

J 1 1 i 1 Fig. 1 illustrates two views of a typical embodiment of the router with replaceable blades for woodworking of the present invention, with two replaceable blades.

Fig. 2 illustrates a horizontal cross section of the router shown in Fig. 1. through the body of the router with two replaceable blades.

Fig. 3 depicts a blade, which can be used in the router of the present invention.

Fig. 4 illustrates another typical router with replaceable blades for woodworking of the present invention, having one replaceable blade.

Fig. 5 filustrates another typical router with replaceable blades for woodworking of the present invention having three replaceable blades.

DETAILED DESCRIPTION OF THE PRESENT INVENTION AND FIGURES

A typical embodiment of the router with replaceable blades for woodworking of the present invention consists of three main functional zones:

9 the shaft, located at, the lower end of the router, designed to be installed in an automated machine which facilitates rotary motion of the router, along its longitudinal axis; the main body, where the blades are installed; and the router head, where optional penetration blade designated for drilling into and penetration of the wood to be processed prior to the router's woodworking operation.

Reference is now made to Fig. 1, illustrating two views of a typical embodiment of the router with replaceable blades for woodworking of the present invention, with two replaceable blades. The router's body (4), is made of metal, and is preferably produced in tuming, milling, sharpening and coating processes. At one end of the router the shaft (1) is located. The shaft serves as the router's installing means on an automated machine which provides a rotary motion to the router, and which guides the router through a predetermined route through the processed wood. Adjacent the shaft the blade support (7) is located, on which the blade (5) is supported, in order to prevent sliding of the blade inside the blade groove (9). The blade support is optionally a resilient ring made of a metal wire, which is kept in place in a circular slit encircling the router body, in which the metal ring is partially inserted. Optionally the blade.support can comprise a spiral spring of several windings, made of a metal wire. The blade groove (9) is carved inside the router body, along its longitudinal surface, and a blade (5) is inserted inside the groove, so that the cutting edge of the blade sticks out of the groove. Reference is now made to Fig. 2, which illustrates a horizontal cross section of the router shown in Fig. 1, through the body of the router with two replaceable blades. The blade groove (9) can be carved along the radial axis of the router, relative to the center of the router (22), but also off the radial axis, as shown in Fig. 2, in order to determine the hook angle of the cutting edge of the blade in respect to the wood to be processed. In a router with 6 1 1 2 more than one blade, the blade grooves are substantially evenly distributed along the router circumference, in order to balance the router when subjected to high-speed rotation. The length and depth of the blade groove is predesigned to accommodate a blade of predetermined dimensions. It is clear that the more blades are located on a router of the present invention, the greater its diameter should be. Typical diameter values for a router of the present invention, using presently commercially available blades of known dimensions, are related to the number of blades installed, as follows:

0 for a single blade - up to 10 mm. for two blades - 12 to 16 mm.

for three blades - 18 to 24 mm.

for four blades 25 to 35 mm.

Obviously, these values are merely recommendations. however the lower values for each configuration are thought to be the lower limit for the router diameter when presently commercially available blades are used.

Reference is now made again to Fig. 1. Directed at the blade groove (9) side wall, passing through the routers main body. at least one bore (10) is provided, having an internal screw thread. The blade is secured in place inside the groove by a screw (8), screwed through a bore, so that the screw presses against said blade frontal plane, forcing the blade back against the groove wall behind it. It is imperative that the screw head, when completely screwed in, be hidden inside the bore and does not stick out of the bore in order to allow for a smooth passage of the router body through the groove produced in the wood being processed by the router action. Alien type screws are suitable for this purpose. Reference is now made to Fig. 3, depicting a 1 7 blade, which can be used in the router of the present invention. Commonly, as mentioned before, the cross section of the blade in its width presents a trapezium-like shape, as the frontal plane (26) of the blade is larger than its back plane (27), and the two elongated sides of the blade present a wedge (28) referred to as the releasing back. At the narrow ends of the blade a penetration edge is provided (29), having a predetermined release angle suitable for penetration of the wood, elther bysliding along the surface of the wood while gradually penetrating the wood, or drilling perpendicularly into the wood. Both sides of the blade are useable, and each side is used at a time. When it becomes blunt, the blade is turned to present its other sharp side. Along the frontal surface of the blade there is an optional niche (30), into which the screw is screwed in, to provide extra firmness of the screw grip of the blade.

In order to prevent damage to the cutting edge of the blade that is directed towards the center of the router, when inserted in the blade groove, the groove is characterized by a specially designed profile (15, shown in Fig. 2), presenting an obstacle to the inserted releasing back (23) of the blade, preventing the blade from being cQmpletely inserted inside the groove, and thus preventing direct contact between the inwardly inserted cutting edge of the blade and the back wall (24) of the groove.

Fig. 4 illustrates another typical router with replaceable blades for wood processing of the present invention, having one replaceable blade. The router head is optionally provided with inclined surfaces (3), to facilitate the discharging of splinters upon penetration of the wood. Optional inclined surface (25) adjacent the blade groove (9) enables the discharging of 8 splinters during the router's employment on the processed wood. Optionally, the router may be equipped with a penetration blade attached to the router's head at its end, either welded or attached in a manner similar to the attachment of the processing blade as described herein.

Fig. 5 illustrates another typical router with' replaceable blades for wood processing of the present invention having three replaceable blades.

Claims

it should be clear that the description of the embodiments and attached

Figures set forth in this specification serves only for a better understanding of the invention, without limiting its scope as covered by the following Claims.

It should also be clear that a person in the art, after reading the present specification could make adjustments or amendments to the attached Figures and above described embodiments that would still be covered by the following Claims.

9 CLAIMS A router with replaceable blades for woodworking comprising a rod having at least one groove along its longitudinal surface, and at least one blade. inserted inside said groove, so that the cutting edge of said blade sticks out of the groove to present a predetermined hook angle, wherein said blade is secured in place inside the groove by means of at least one screw, screwed through a bore in the rod, having matching internal screw thread, directed at said blade frontal plane, so that the screw presses against said blade frontal plane, forcing the blade back against the groove wall behind R.
2. The router according to Claim 1, Wherein said router body is metallic.
3. The router according to Claims 1 and 2, wherein said router body is made of metal produced in turning, milling, sharpening and coating process.
The router according to Claim 1, wherein said blade is supported inside the groove by a resilient ring, encircling the router body.
5. The router according to Claim 4, wherein said resilient ring is made of a metal wire.
6. The router according to Claim 1, wherein said blade is supported inside the groove by a spiral spring.
7, The router according to Claim 6, wherein said spiral spring has several windings.
8. The router according to Claim 1, wherein said blade groove is carved along the radial axis of the router, relative to the center of said router.
9. The router according to Claim 1, wherein said blade groove is carved off the radial axis of the router, relative to the center of said router, in a predetermined angle.

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10. The router according to Claim 1, having more than one blade, wherein the blade grooves are substantially evenly distributed along the router circumference.
11. The router according to Claim 1, wherein said blade has a niche along its frontal surface, into which the screw is screwed in.
12. The router according to Claim 1, wherein said screw head, when completely screwed in, is hidden inside the bore and does not stick out of said bore.

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13.

The router according to Claim 1, wherein said blade has two opposite cutting edges, one of which is inserted inside said groove, and which can be turned outwards, when the other cutting edge becomes blunt.
14. The router according to Claim 13, wherein said blade groove is characterized by a predetermined profile, presenting an obstacle to the inserted releasing back of said blade, preventing the blade from complete insertion inside said groove, thus preventing direct contact between the inwardly inserted cutting edge of said blade and the back wall of the groove.
15. The router according to Claim 1, wherein said router head is provided with inclined surfaces, to enable discharging of splinters.
16. The router according to Claim 1, wherein adjacent said blade groove there exist an inclined surface, to enable discharging of splinters.
17. The router according to Claim 1, wherein said router is provided with a penetration blade, attached to its head at its end.
18. The router according to Claim 17, wherein said penetration blade is welded to the router.

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19. The router according to Claim 17, wherein said penetration blade is inserted in a groove and attached to the router by means of at least one screw.
20. A router with replaceable blades for wood processing substantially as described in the above specification, attached Figures and appending Claims.
21. A router substantially as hereinbefore described with reference to the accompanying drawings.

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