FR2813221A1 - Axial guide for rotating boring tools has movable housing for tool shank or shank extension, guide recess section guaranteeing concentricity - Google Patents

Abstract

The axial guide body (7), when detached from the support body (8), has a movable housing for the tool shank (3) or shank extension (6). The guide recess (7a) has a cross section guaranteeing its concentricity. The end of the support body is placed in a guide trunnion (9).

Description

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The invention relates to an axial guide for tools driven in a rotary manner, in particular boring tools, with a cylindrical rod and rod extensions equalizing different diameters of rods, with a guide body a guide body provided with a guide recess defined for gripping tool rods or rod extensions with at least one partially cylindrical inner wall trace of respectively adapted diameter - seen in section - and a support body placed on a fixing device, with at less an axially round recess formed for the housing of the guide body and an access recess passing through a freely accessible side wall section of the support body parallel to the axis of revolution and opening towards the outside, d '' a free width adjusted to the diameter of the tool rods or rod extensions.

Such axial guidance is described in document DE-G 94 07 025, and known for the biasing reaming device intended for drilling holes in inclined stringers of wooden stairs. The drills used for this purpose have a cylindrical male socket and a removably placed cutting head. They are exclusively used with two different cylindrical rod extensions, thanks to which the two rod diameters are equalized.

The known axial guide is formed by a solid support body of cubic shape placed on a fixing part of this oblique reaming device and a hollow guide body in the form of a sleeve inserted in a recess axially cylindrical formed round, the recess produced here as a blind hole or through hole being locked by one or two cover-shaped plates.

In the front wall of the support body, a slot-shaped recess is formed parallel to the axis of revolution with a free width adjusted to the diameter of the extension of the rod. It is extended at each U-shaped end in the support body or the locking plate (s).

A corresponding slot-shaped recess also has the guide body, and therefore has a U-shaped section.

By pivoting the guide body in the support body, the two recesses can be brought together in overlap, so that the

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 extension of the rod clamped in a hand-operated drill can be inserted from the side through the wall of the support body and then from the guide body into the latter, until it is adjacent, by section, to half the circumference of the walls of the two U-shaped recess extensions.

If the guide body is pivoted 180 in the support body, its outer wall locks the recess of the support body and its inner wall is adjacent to the half of the periphery of a corresponding section of the extension of the rod, due of its only semi-cylindrical section shape depending on its recess. The concentric guide of the rod extension is thus separated therefrom on three mutually opposite sections at a distance from each other.

This concentric guiding existing thanks to a cooperation by section of three axial guiding surfaces defines great requirements as for the dimensional stability of the parts having these guiding surfaces. Because very small dimensional variations during manufacture as well as during assembly lead either to higher friction going up to seizing, or to a play of the extension of the rod in the two extensions of the U-shaped recess. These two consequences lead to rapid wear of these elements, in particular of the guide body preferably made of zinc bronze.

A high friction also causes rapid heating of the guide body which then expands, and therefore can no longer be pivoted in its extended position after the end of the reaming process, in order to be able to remove the extension of the rod again. outside the support body. This extends the hole reaming process. Furthermore, this results in the fact that, in order to slow down this heating, it is not necessary to machine with the highest possible drill speed, which again results in a tearing of the wood when the cutting head is plunged. forest in the wood.

To avoid this as much as possible, the cost, during the manufacture of the parts as during the assembly of the parts of this axial guide, must be reduced and appropriate, without however being able to avoid a subsequent adjustment which takes time.

The object of the invention is to improve the known axial guidance for tools driven in rotation, so that the aforementioned drawbacks are eliminated without affecting the simple handling of a device thus equipped.

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 The object of the invention is resolved by axial guidance for tools driven in rotation, in particular boring tools, with a cylindrical rod and rod extensions equalizing different rod diameters, characterized in that the guide body represents, in the detached state from the support body, a movable piece for housing the tool rod or the rod extension, the guide recess having a sectional shape guaranteeing its concentricity.

The guide is further characterized in that - the support body is placed at its end on a guide pin and has a cubic shape.

- The guide body is formed like a hollow cylinder in the form of a socket.

- The recess of the guide body is formed as a passage opening in the support body.

- A collar-shaped support ring is formed on the upper end of the guide body.

- The access recess is formed in the middle of the lateral surface of the support body opposite the guide pin.

a slot-shaped locking recess is formed openly towards the access recess, directed radially at mid-height in the wall of the lateral surface of the support body adjacent to the access recess and situated, seen from above, left clockwise.

- A rod-shaped locking element, projecting radially, is arranged on the outer wall of the guide body and cooperates with the locking recess.

- The locking element is formed in a hollow cylinder, placed in a through bore in the guide body, a spring element being provided there.

- A sliding box, composed of a material having lubrication properties, in particular sintered bronze, is inserted in the guide body. Because the guide body represents, in the state detached from the support body, a movable piece for housing the tool rod or the rod extension, the guide recess having a sectional shape guaranteeing its concentricity, an axial guide device of the known type can be manufactured at an advantageous cost and used effectively in several respects.

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 Thus parts and working steps used until now, and therefore their cost during manufacture or assembly, can be eliminated. Instead, the concentricity of a preferably used rod extension can be obtained by a single piece, furthermore made simply, namely the guide body.

As this guide body, according to the invention, represents a movable part, i.e. a part removably connected to the support body forming with it an axial guide, therefore a part which is not fixedly held to this support body, for example by locking plates, as was the case up to '', it can therefore at any time be removed directly from the support body to place it, in a freely movable manner, on the free end of the top of the rod extension not yet tightened in the drill and then to make it slide on it or slide it inverted from below in its guide recess.

This possibility of placing the rod extension outside the support body in the guide body, or conversely on the rod extension, makes the slot-shaped recess used hitherto used for this purpose unnecessary. in the wall of the guide body. Thus, the guide body may also have, for taking the extension of the rod, a guide recess for example, entirely cylindrical, i.e. of circular section, with a corresponding closed inner wall for guidance on all sides (concentric) of the extension of the rod, or at least one closed inner wall with only one predominant slot, i.e. narrower in width than the diameter of the housing rod extension.

This also makes the U-shaped recesses, hitherto used for axial guidance, superfluous on the support body or in the locking plate (s), these latter even being able to be entirely eliminated in a corresponding embodiment of the guide body. If there is therefore no longer contact between these recesses and the extension of the rod, no more frictional heat, causing the blocking of the guide body in the support body, can occur. It is also no longer necessary to be careful, because the drill can then plunge into the wood to be drilled at maximum speed, like a milling machine, which can avoid the dreaded tearing of the wood. High speeds

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 drilling also means faster hole boring, thus saving working time.

If the locking plates provided so far not only on one, but also on both sides of the support body, can be omitted, as well as the provision of the slot-shaped recess in the wall of the guide body, and therefore the realization of these parts with exact dimensions very important so far, as well as the precise assembly and the subsequent adjustments to exact dimensions also, which take time, one can then obtain a corresponding very profitable manufacture of such axial guidance. The invention therefore has a considerably economic effect, in addition to the improved working method and use of the axial guide thus formed.

Due to the concentricity obtained, for example for the rod extensions, already due to the guide recess formed in a cylindrical and closed manner in the guide body, therefore in particular without the said locking plates, the risk is also avoided premature wear of the guide body, these locking plates and the rod extension, and this new axial guide device can therefore be used longer.

The guide body is advantageously formed like a hollow cylinder, namely a sleeve or a sleeve in the form of a turned part which can be produced at low cost according to production techniques, with an internal diameter adjusted to the diameter of the rod of the tool or rod extension for the formation of a guide recess. The latter can also be cost-effectively formed as a through hole or as a through bore.

In this case the recess of the guide body formed in the axially round support body, as was the case so far, can be maintained unmodified, i.e. that the unmodified support body can be used with the new guide body produced according to the invention, if the latter has the same outside diameter as that used up to now.

One can also imagine making the guide body similarly to the support body, for example square or cubic in shape, so that the recess of the guide body in the support body will be less advantageous to manufacture, because '' must also be trained

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 corresponding square rather than round, so that such a guide body can be removably inserted into the support body.

In order that the guide body according to the invention does not fall outside the support body downwards in the case of an axis of rotation generally directed vertically, a support ring in the form of a collar can advantageously be formed on its upper end, with which after its insertion in the support body it rests on the upper side thereof, and thus be held by the support body. Such a support ring, preferably knurled, also facilitates the grip of the guide body, for example to remove it from the support body.

A preferred embodiment of the invention is described in the following with the help of a schematic drawing.

The drawings show a perspective representation of a biasing reaming device, as it is widely known from document DE-G 94 07 025, and namely in a main view without, and in a side view with, a drill equipped ready to be used for drilling, and fixed against it.

With the biased reaming device indicated, holes can, for example, be drilled in the inclined stringers of wooden staircases for mounting a banister and stair steps. For this purpose it has a so-called support or fixing part 1, fixed on the stair stringer concerned with a clamp 2 for boring in the vertical direction indicated.

The drills used for boring holes have a cutting head 4 removably placed on a cylindrical rod socket 3. These rods 3 have a uniform diameter of 9 mm in the case of a first set of drills with head diameters of for example from 10 to 25 mm, and which amounts to 12 mm in the case of a second set of drills up to 26 to 49 mm. Due to the space taken up in height by the biasing boring device and the required drilling depth, the drills of the first set of drills are mounted respectively in the drill chuck of the drill 5 controlled manually, by means of a rod extension 6 about 18 cm long and an external diameter of 12 mm, after their rod 3, as indicated, has been pushed into this rod extension 6 and screwed onto one of the pins threaded formed therein. Conversely, the rods of the other set of drills are screwed, with their threaded journals

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 formed respectively in a terminal manner, in a corresponding tapped terminal hole with a shorter extension also with a diameter of 12 mm, adjacent to it by flushing it.

In order to be able to orient the drill mechanically assisted in the direction of its axis of rotation during reaming with the biasing reaming device indicated, an axial guide is provided here for extending the rod, ie a guide device formed as axial guidance. It is formed by a hollow cylindrical guide body 7 made of metal in the form of a socket and by a solid support body 8 of cubic shape made of metal receiving the latter. This support body is held by means of a flattened pin 9 with notches placed on it, locked in rotation by the fixing part 1, axially displaceable laterally and capable of being blocked, and has as a passage opening a body recess guide 10 cylindrical adjusted to the guide body 7.

After the fixing part 1 has been fixed for example to a stair stringer to be provided with bore holes by means of the clamp 2, the guide body 7 according to the invention, movable, removably placed in the support body 8, is removed from it and slid from the top on the extension of the rod 6, or slid from the bottom in the guide body 7, and pushed for example to its middle. A so-called annular depth stop 11 can still be slid from the top on its free end and be blocked to define the depth of the bore hole on the rod extension 6, before this end is mounted in the drill chuck 5 which may be in a position facilitating this process, for example on the body performing the tightening.

A hollow spindle 12 is screwed into a threaded passage opening in the wall of the guide body 7. A spring pressure piece is inserted therein so that its spring loaded sphere protrudes much, depending on its function, from the side inside the wall of the guide body 7. When the guide body 7, as shown, is slid over the rod extension 6, it is held by the sphere of the pressure piece by spring in the position taken and does not slip downwards for example on the rod extension 6. This facilitates the subsequent manipulation of the rod extension 6 with the guide body 7 placed on it.

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 With the drill 5, the rod extension 6 which is mounted therein is maintained, with its section under the guide body 7, before the access recess 13 in the form of a slot formed parallel to the axis of revolution in the wall of the support body 8 with a free width adjusted to the diameter of the rod extension 6, or so to speak before the entry recess of the rod extension, parallel to the latter, it is then guided through the recess 10 of the guide body in the support body 8 and is immersed therein until the guide body 7 is received by the latter or by the support body 8, possibly after an orientation of the spindle 12 corresponding to the access recess 13, and it rests on the support body 8 with its support ring 14 in the form of a collar on its upper end. To facilitate the insertion of the guide body 7 into the recess 10 of the guide body, a chamfer is formed on its lower end, as above on the support ring 11. For reasons of handling, the ring support 11 is knurled around its periphery.

This insertion of the rod extension 6 into the support body 8 is facilitated by the fact that the access recess 13 provided for this purpose is located on the opposite side of the guide pin 9, practically on the front side of the body. support 8, most easily accessible by the fixing part 1 of the biasing reaming device fixed on the stair stringer, namely from the side.

When the guide body 7 is inserted into the support body 8, the pin 12 is at the level of an additional locking recess 15, in the form of a slot, extending in a radial level on the left side in the wall of the support body 8. The pin 12 can be pivoted 90 clockwise in this recess to lock the guide body 7 on the support body 8. Thus the guide body 7 can be locked relative to the extension of rod 6, so that it does not participate in the lifting movements triggered manually by the drill 5 to transport the chips out of the borehole, and therefore that it does not slip from the support body 8, but also to prevent rotation of the guide body 7 in the support body 8 during reaming, as also to secure it against falls during transport of the reaming device at an angle.

Once the drilling has been carried out, the locking of the guide body 7 is loosened in the support body 8 by again rotating the spindle 12 90 counterclockwise until the access recess 13. The extension of rod 6

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 still in the drill can be pulled up into the support body 8 with the drill, until the guide body 7 manually supported by pulling on the support ring 11 is removed from the support body 8. The extension 6 can also be removed from the support body 8, facing the cutting head of the much larger drill, laterally by the access recess 13, and the drill 5 can be removed with the extension rod 6 with the drill bit and the guide body 7 for example temporarily, for example to loosen the clamp 2, to push the support or fixing part 1 in the next boring position, for example on the stringer d 'staircase, and to fix it again with the clamp 2. Then the drill 5 can be taken again, which saves time, and inserted and plunged, with the extension of rod 6 which is always mounted, through the access recess 13 in the support body ort 8, until the guide body 7 rests again with its support ring 14 on the guide body 8.

To reduce friction, a sliding box, made of a material having lubricating properties such as for example sintered bronze, can be inserted in the guide body 7, or a sliding box with a corresponding internal coating, as for example example with polytetrafluoroethylene known as teflon.

In order for the operation of the spring pressure piece to be effective by means of such a sliding box, either this has a corresponding recess, or it is interrupted or separated in the form of an annular passage, or there are two boxes of this type at a distance from each other.

Such a sliding box simplifies a possibly necessary repair of the guide body, since only the sliding box needs to be changed.

The guide body is preferably made of special steel, which also has an advantageous optical effect, since it cannot rust or be stained, as in the case of zinc bronze.

One can also imagine, instead of placing the guide body 7 according to the invention removably in the support body 8 and therefore formed as a hollow closed cylinder in the form of a socket, to place it stationary in the body support 8, the support body 8 then being placed

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 in such a way that on the fixing piece 1 that it could be pivoted simply, for example after loosening a corresponding blocking, in the position of the biased reaming device indicated, for example clockwise, for example 90, on the part 1. In this position the rod extension 6 could be slid from the left side in the guide body 7 fixedly placed in the support body 8, the support body 8 would be pivoted back to its vertical position , and mounted and locked on the section of the rod extension 6 or the depth stop 11 protruding upwards. The drill 5 could then be inserted on the free end of the rod extension 6 and the latter would be tightened in its mandrel.

11 is however obvious that this method in relation to a guide body 7 according to the invention, however placed stationary in the guide body 8, would be very complicated and also impractical. Because it would first be necessary to open the mandrel each time the reaming device is moved to the next reaming position to drill a new hole, in order to be able to remove the heavy drill 5 from the rod extension 6, the loosening of the mandrel being difficult then, because the drill could not be kept in a position facilitating this operation. In the case, for example, of twenty holes to be drilled one after the other to mount banisters and stair treads in a stair stringer, such a process would take a great deal of time and would not be practicable.

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Claims (10)

1. Axial guide for tools driven in rotation, in particular boring tools, with a cylindrical rod (3) and rod extensions (6) equalizing different rod diameters, with - a guide body (7) provided with a guide recess (7a) defined for gripping the tool rods or rod extensions (6) with at least one partially cylindrical inner wall trace of respectively adapted diameter - seen in section - and - a support body ( 8) placed on a fixing device (1), with at least one recess (10) formed axially round for housing the guide body and an access recess (13) passing through a side wall section freely accessible from the support body (8) parallel to the axis of revolution and opening towards the outside, of a free width adjusted to the diameter of the tool rods or rod extensions (6), characterized in that the body guide (7) represents, in the detached state of the support body (8), a movable piece for housing the tool rod or the rod extension (6), the guide recess (7a) having a sectional shape ensuring its concentricity. 2. Axial guide according to claim 1, characterized in that the support body (8) is placed at its end on a guide pin (9) and has a cubic shape. 3. Axial guide according to claim 1 or 2, characterized in that the guide body (7) is formed as a hollow cylinder in the form of a socket. 4. Axial guide according to claim 3, characterized in that the recess of the guide body (10) is formed as a passage opening in the support body (8). 5. Axial guide according to claim 3 or 4, characterized in that a support ring (14) in the form of a collar is formed on the upper end of the guide body (7). 6. Axial guide according to one of claims 2 to 5, characterized in that the access recess (13) is formed in the middle of the lateral surface of the support body (8) opposite the guide pin (9) . <Desc / Clms Page number 12>  7. Axial guide according to claim 6, characterized in that a locking recess (15) in the form of a slot is formed openly towards the access recess (13), directed radially at mid-height in the wall. from the lateral surface of the support body (8) adjacent to the access recess (13) and situated, seen from above, to the left in a clockwise direction. 8. Axial guide according to claim 5 and 6, characterized in that a locking element (12) in the form of a rod, projecting radially, is disposed on the outer wall of the guide body (7) and cooperates with the locking recess (15). 9. Axial guide according to claim 7, characterized in that the locking element (12) is formed as a hollow cylinder, placed in a through bore in the guide body (7), a spring element being provided there. 10. Axial guide according to one of claims 3 to 8, characterized in that a sliding box, composed of a material having lubrication properties, in particular sintered bronze, is inserted in the guide body (7) .