APPARATUS FOR THE OBTENTION OF ANNULAR CAVITIES AT THE BOTTOM OF DRILLS MADE ON SURFACES OF ANY KIND

Abstract: The invention refers to a device for the obtention of an­ nular cavities at the bottom of drills made on surfaces of any kind. The apparatus, which may be coupled to any motor el­ ement as a conventional drilling machine, incorporates an axle of a considerable length, edged in a cutter, provided with a rotating movement, which axle is housed in a cylindrical piece, in a sharply eccentric mode, said piece also receiving a rotating element with respect to the fixed body, of the appar­ atus in its whole, so that the cutter and the fixed body remain perfectly coaxial when introduced in the drill, and by rotating the cutter at a high speed, a slow rotating movement of the casing piece determines the progressive eccentricity of the cutter with respect to the fixed body, for the obtention of the annular cavity which is pursued. On the fixed body itself, in parallel with the axle of the cutter, and to the moving piece which houses it, is set forth a conduct for the refrigeration water of said cutter.

Description: The present invention refers to an apparatus that has been specially designed for creating undercut annular cavities or radial enlargements at the bottom of drilled holes previously made in any kind of surfaces, preferably in concrete walls although the said surfaces can obviously be of stone, brick, steel, etc. The applicant is the owner of the Spanish Patent of Invention nº 548.461, which consists of a series of improvements introduced in anchoring systems by means of threaded bolts, an anchoring system which required, in the wall or surface a hole provided with an undercut annular cavity at its bottom. Therefore, the apparatus which the invention proposes is specially designed for creating such an undercut annular cavity at the bottom of the hole, allowing the said anchoring system by means of threaded bolts to be applied. An other apparatus capable of undertaking an operation of this type is known under the FR-A-I 443 246 which discloses an apparatus for annular cavities at the bottom of drilled holes in any kind surface which is constituted by a body, fixable to a machine tool, as for instance a lathe, provided with an axial hole for an axle of considerable length, whilst at its other end is fixed a cutter whereby said axle is housed in a hole in a generally cylindrical casing piece which extends from said body to the cutter and with the particularity that said hole is eccentric, said casing piece being provided at its first end with a larger head which is susceptible of rotating with respect to the fixed body, in such a way that when the casing piece is located with the eccentricity in a first position, the cutter is aligned substantially axial with respect to the casing piece and the apparatus is adjustable in the drilled hole in which it is pretended to perform the annular cavity, whereby the rotation of the casing piece with respect to the fixed body determines the radial offset of said cutter up to a limit set by the eccentricity of it own hole, and the simultaneous rotation of said casing piece and the workpiece causes a hypocycloidal movement of the cutter, which determines in turn the size of the annular cavity. The apparatus according to the invention performs its work with the cooperation of a cutter, of a nature in accordance with the type of material which the wall of the hole is composed of, which is driven with the aid of a conventional drilling machine the ouput head of which has a shaft coupled to it, to which the said cutter is fixed, but with the special feature that the said shaft is housed in a longitudinal and eccentric hole in a second casing piece so that the external casing piece presents a diameter which corresponds to that of the hole previously drilled in the surface, and an operational length in accordance with the depth of the said hole, the diameter of the cutter also coinciding with the diameter of the said hole, it having been provided for that in a certain relative position for both casing pieces, their eccentricities counteract each other and the shaft of the cutter is substantially aligned axially in relation to the external casing piece which allows it to penetrate freely into the hole, whilst from this position and by means of a rotation of the internal casing piece, a radial motion of the cutter is started so that it emerges radially in relation to the external casing piece and in consequence it begins work on the side wall at the bottom of the drilled hole, whilst at the same time a rotation of the external casing piece causes a progressive change of position of the whole assembly, and more precisely, its working area will be able to describe a circumferential trajectory coinciding with the annular cavity to be created. As a complement of the structure described above which corresponds to claim 1 and as another feature of the invention according to claims 2 to 4, the apparatus has been provided with a means of cooling the cutter whilst it is operating, for which purpose an elastically deformable annular chamber has been defined in the external casing body, and more precisely in the area where it adapts to the front of the surface which seals it with the surface itself, a water, or any other cooling liquid, inlet channel being located on the inside of the said casing piece parallel to its shaft, which flows out into the end where the cutter is located and which returns removing the debris caused by the normal operation of the cutter, returning to the outside through the interstice defined between the wall of the hole itself and the external surface of the casing piece until reaching the said chamber which is duly connected to the water disposal conduit or pipe. To complement the description to be made hereunder and for the purpose of aiding a better understanding of the characteristics of the invention, attached to the present specification as an integral part of it, is a set of drawings in which, with an illustrative and non limitative character, the following have been depicted: Figure 1.- Shows a side elevation view of an apparatus for creating undercut annular cavities at the bottom of drilled holes made in any kind of surface, according to the subject matter of the present invention. Figure 2.- Shows the same assembly as the previous figure diametrically sectioned. Figure 3.- Shows a sectional view of the same apparatus, in accordance with the A-B cutting line of Figure 2 and in which the mechanisms transmitting the rotational motion to the internal casing piece are seen in detail. Figure 4.- Shows another cross-section of the apparatus, made in this case in accordance with the C-D cutting line of Figure 2, in which in turn, the means limiting the rotational motion of the second casing piece or external casing piece are seen. Figure 5.- Shows a sectional view of the apparatus at the level of the area of insertion within the drilled holed and in accordance with the E-F cutting line of Figure 2. Figure 6.- Shows the same view as the previous Figure, in a variant of the embodiment, in which the cooling conduit is not arranged within the external casing piece, but rather between both casing pieces. From these figures it can be seen how the apparatus, which is preconized, is constituted from a body (1) to be coupled to the housing of a drilling machine that has been schematically represented and referenced at (2) to which it is fixed with the aid of a clamp (3) or by any other conventional means, whilst at the same time the rotating head of the said machine is fixed to a shaft (4), evidently coaxial, the length of which will conform to the depth of the drilled hole, in accordance with the device's structure to be described hereunder and it ends in a cutter (5) in combination with which the annular cavity is to be created, the cutter being fixed to the said shaft (4) with the aid of a nut (6) in association with an threaded end portion of the shaft (4). The shaft (4) which crosses the body (1) axially is in turn housed within a casing piece (7) which extends to near the cutter (5) and which in its initial portion (8) presents an area considerably expanded radially through which it engages with a gear wheel (9) preferably with the aid of screws (10), although the said gear wheel can be formed as a single piece with the portion (8) itself of the piece (7),the said piece (7-8-9) being in its whole capable of rotating in relation to the body (1) to which it is related through bearings (11) and characterized in that the shaft itself can rotate within this casing piece (7), but with the special feature that the hole created for that purpose in the said piece, with a diameter in accordance with that of the shaft itself (3) is located in a notably eccentric position over the said piece. In turn, the casing piece (7) is housed within a second casing piece (12), the latter being provided with a longitudinal eccentric and cylindrical hole with a diameter coinciding with that of the piece (7) which moves tightly within the external piece (12). Also this external casing piece (12) is provided with a larger head (13) which rests on the annular step defined between the internal casing piece (7) and its expanded end (8), as can be seen in detail in Figure (2). The length of the shaft (4) and that of the casing pieces (7) and (12) is such that, between the face defined by the larger head (13) of the external casing piece (12) and the cutter (5) a size is created which is in accordance with the depth of the drilled hole in which it is intended to make the annular cavity. From the foregoing, it is deducted that for the cutter (5) do its work, its rotational movement is carried out by the drilling machine coupled to the apparatus, and the possibility of the two casing pieces (7) and (12) rotating, and the eccentric mounting between these pieces and the shaft itself (4) determine that when the cutter rotates, which rotation at a certain position is coaxial with the external casing piece (12) to facilitate its implantation in the drill, the said cutter moves radially simultaneously with a planetary movement which in combination with its rotation are going to create the intended rebated annular cavity at the bottom of the drilled hole. As a complement to the structure described and specifically at the heads (8) and (13) of the casing pieces (7) and (12), the controls of the apparatus are established to control and vary the eccentricity of the cutter within the drilled hole. More precisely, the above mentioned bearing, as well as the gear wheel (9) associated with its head participate in the mobility of the casing piece (7), the said gear wheel engages with a worm gear (14) installed over the body (1), the said worm gear (14) having an axial extension ending in a pinion (15) which engages with another crown gear (16) solidly joined to a rotating handle (17). The solution adopted for this movement, that is, the crown-spindle drive, has been chosen as preferential as it keeps the shaft casing piece (7) locked in position, when the (17) handle is freed, but obviously this assembly can be replaced by another type of conventional drive. In a similar way, the said handle (17) can be replaced by a crank, handwheel or any other conventional means of drive, without this affecting the essence of the invention either. Also forming part of the means of operating the apparatus, a ratchet (18) has been fitted on the body (1) the claw (19) of which enters the radial slot (20) existing in the head of the external casing piece (12) as seen in full detail in Figure (4). In addition, in the head of the internal casing piece (7) there is a stub (21) with which a projection (22) located on the head of the external casing piece (12) cooperates. More specifically, the projection (22) is located on the head of the piece (12), so that the stub (21) of the piece (7) laterally abuts one of the ends of the said projection (22) when the drills passing through both casing pieces (7) and (12) are orientated in the opposite direction, and with the other end of the said projection (22) when orientated in the same direction. Thereby, the projection (22) is extended along a 180 º arc as can also be seen in detail in Figure 4 or rather it extends along an arc allowing the stub (21) of the piece (7) to rotate 180º according to the thickness of the latter. Since, as deducted from the foregoing only the ends of the projection (22) are operative, they can be replaced by two simple stubs located in correspondence with the ends of the said projection (22), or by any other equivalent stop system. From the above mentioned arrangement, it is understood that during the operation of the apparatus the external casing piece (12) can be operated in two different ways: either leaving it inactive, securing it to the body (1) through the ratchet (18), or making it rotate on being pulled by the internal casing piece (7) when the stub (21) of this piece pushes on the projection (22) of the external casing piece (12). The operation of the apparatus is as follows: The body (1) of the apparatus is coupled to a drilling machine (2) or to any other motor unit. The casing piece (12) is located so that its slot (20) is opposed to the ratchet (18). This ratchet is actuated so that its claw (19) enters the said slot (20), with which the external casing piece (12) is secured to the body (1). Afterwards, the internal casing piece (7) is rotated, in relation to the external casing piece (12) until the eccentricities of their respective perforations are orientated in opposite directions, at which time the cutter (5) and its corresponding shaft (4) are located in a notably axial arrangement of the assembly which allows the apparatus to be inserted into the hole previously drilled in the concrete, until the head (13) of the external casing piece (12) abuts the surface of the wall. Then the handle (17) is rotated, which through the corresponding already described drive causes the internal casing piece (7) to rotate, the external casing piece (12) remaining static, with which the eccentricities of their respective longitudinal drilled holes change their relative orientation and in consequence the cutter (5) is moved laterally in relation to the piece (1), impinging on the side surface of the drilled hole, cutting away material to attain the desired annular cavity. Once the piece (7) has rotated 180º in relation to the external piece (12) the stub (21) contacts the projection (22) and then the claw (19) of the ratchet (18) is extracted from the slot (20) after which both casing pieces (7) and (12) rotate together, pulling the internal casing piece towards the external one, when the stub (21) pushes the projection (22). The handle (17) continues to be operated until the shaft (4) located in its most eccentric position rotates 360º and consequently the eccentricity completes its work in shaping the annular cavity. In this position, the claw of the ratchet (18) is again opposed to the slot (20) of the external casing piece (12). If it is desired to make a cavity in only part of the perimeter of the drilled hole, the casing pieces (7) and (12) can be rotated to the foreseen angle for such a cavity instead of the said 360º maximum angle. When the foreseen angle is completed, the handle (17) is rotated in the opposite direction until the claw of the ratchet (18) is opposed to the slot (20). Both in the case of the annular cavity being partial and in the case of it being total, the ratchet (18) is then activated again to lock the external casing piece (12), its claw (19) entering the slot (20), and then the handle (17) is rotated in the opposite direction to that used before until the stub (21) abuts the opposite end of the projection (22), in which position the eccentricities of the longitudinal perforations of the casing pieces (7) and (12) are orientated in the opposite direction, which is equivalent to the cutter (5) having again adopted a coaxial position with the apparatus as a whole, and this latter can be extracted from the drilled hole in question. In conclusion, by inserting the apparatus in a drilled hole or perforation in which the external casing piece (12) is perfectly adjusted and by operating the apparatus in the specified manner, the cutter (5) is initially moved laterally or radially in relation to the said casing piece (12) with which it penetrates the wall of the drilled hole thus starting the desired cavity, whilst the latter joint rotation of both casing pieces determines the said planetary motion of the cutter, parallel to the rotary motion of the latter, which give rise to the cutter moving around the periphery of the drilled hole shaping a complete or partial annular cavity, according to whether these two casing pieces rotate at an angle less than or equal to 360º. In practice, the operation of the apparatus, in accordance with the said arrangement is perfect from the theoretical point of view, and for the cutter to be able to carry out the cutting of the drilled hole, especially when the surface is composed of hard materials, as in the preferred and aforementioned case of concrete, it is necessary for it to be cooled. In this respect, it has been foreseen that the external casing piece (12) incorporates additionally a conduit (23) clearly evident in Figures (2) and (5) to introduce cooling water into the working area of the cutter and likewise, to remove the debris produced. Optionally and in accordance with the depiction in Figure (6), the conduit (23) can be shaped in a slot (23) made over one of the generatrix of one of the two casing pieces (7) and (12), more specifically over an external generatrix of piece (7) or over a generatrix of the internal hole of the piece (12) the said slot being closed to form the desired conduit with the other piece, as seen in full detail in the said Figure (6). In addition, along a generatrix of the external surface of the external casing piece (12) there is a rebate (24) which with the surface itself of the hole drilled in the concrete, defines an outlet channel for the cooling water and the said debris. This rebate (24) in the piece (12) is located opposite the arc which the shaft (4) describes when the internal casing piece (7) is rotated thus preventing the external casing piece (12) from moving. The said rebate (24) thus always remains opposite the area of the piece (12) which presses against the surface of the hole drilled in the concrete as a reaction to the resistence the said concrete presents to the penetration of the cutter (5). More precisely, for connecting the cooling system a cylindrical piece (25) as been fitted to which the inlet (26) and the outlet (27) pipes for cooling water are connected. This piece (25) is mounted around the head (13) of the external casing piece (12) as seen in Figure (2) so that it can rotate freely in relation to it. Therefore the piece (25) remains stationary when the piece (12) rotates. On its front area, the piece (25) incorporates a ring (28) made of watertight and elastic material, intended to fit closely against the surface of the wall, when the head (13) of this piece abuts the said surface. Besides, the piece (25) incorporates an annular chamber (29) perimetrally closed by the said ring (28), provided for collecting the cooling water, and incorporated in the front of the head (13) which abuts the surface there is a radial rebate for connecting the longitudinal rebate (24) to the said chamber (29), which is evidently connected to the outlet pipe (27). The head (13) in correspondence with this annular piece (25) presents a perimetral groove (30) which, with the annular piece (25) forms a chamber which is also annular, aided by seals (31), to which chamber (30) the inlet piping accedes, and from which the conduit (23) which is directed towards the working area of the cutter, emerges. As is evident in Figure (2), the water inlet (30) and water and debris outlet (29) chambers are completely independent. From the arrangement described, it is deduced that the cooling water arrives at the device through the inlet (26), enters the chamber (31) and from it the conduit (23) to reach the working area of the cutter from where, once it has accomplished its cooling task and removed the debris, it returns again to the exterior by means of the channel defined by the rebate (24) of the apparatus and the wall of the hole, reaching the chamber (29) and from it flows to the exterior through the outlet (27). It should also be pointed out that in order to avoid leaks of cooling water around the shaft (4), the same is protected by a pair of seals (32). The materials, shape, size and arrangement of the elements will be susceptible to changes whenever this does not suppose an alteration in the essence of the invention. The terms in which this invention has been described should be taken in a broad and non limitative sense, the extend of protection being determined by the terms of the claims.

Claims: APPARATUS FOR CREATING UNDERCUT ANNULAR CAVITIES AT THE BOTTOM OF DRILLED HOLES MADE IN ANY KIND OF SURFACES, which is constituted by a base body (1) fixable to the housing of any conventional motor unit (2), as for instance a drilling machine provided with an axial hole for a shaft (4) of considerable length, which at one of its ends is driven by the said motor unit (2), whilst its other end is fixed to a cutter (5) to which it transmits rotary movement, whereby the said shaft (4) is housed in a hole in a generally cylindrical casing piece (7) and mobile, which extends from the said body (1) to the cutter (5) and with the special feature that the said hole is markedly eccentric, the said casing piece (7) being provided at its first end with a larger head (8) which is capable of rotating in relation to the fixed body (1), through bearings (11), or similar means, characterized in that over this casing piece (7) is coupled a second casing piece (12) which extends between the head (8) of the first casing piece (7) and the cutter (5), provided as well with a radially larger head (13) at its first end and with a hole for the housing of the internal casing piece (7), which is also markedly eccentric, in such a way that when both casing pieces (7) and (12) are located with the eccentricities of their holes opposite, the cutter (5) is substantially aligned axially in relation to the external casing piece (12) and the apparatus is adjustable in the drilled hole in which it is intended to create the undercut annular cavity, whereby the rotation of the internal casing piece (12) determines the radial rebate of the said cutter (5) up to a limit set by the eccentricity of it own hole, and the simultaneous rotation of both casing pieces (7) and (12) causes a planetary movement of the cutter (5), which in turn determines the size of the undercut annular cavity. APPARATUS FOR CREATING UNDERCUT ANNULAR CAVITIES AT THE BOTTOM OF DRILLED HOLES MADE IN ANY KIND OF SURFACES, as per claim 1, characterized in that for the rotation of the internal casing piece (7) the latter incorporates in its head, either as one single piece, or duly fixed to the same, a gear wheel (9) to which a worm gear (14) is engaged, or any other rotating gear mounted in the body associated to the corresponding manual control, also the base body (1) having been provided with a ratchet (18) with a claw (19) locking into a radial slot (20) of the head (13) of the external casing piece (12) to attach the latter rigidly to the said body and consequently to prevent it from moving: also the head (8) of the internal casing piece having been provided with a stub (21) capable of abutting the ends of a projection (22) on the head (13) of the external casing piece (12), so that the internal casing piece, on rotating can pull the said external casing piece in one or other direction upon the said stub impinging on the operational ends of the said projection, when the ratchet frees the external casing piece, with the special feature that the said projection (22) adopts a semi-circumferential shape, defining between its ends an angle of 180º. for the pulling stub, linked to the head of the internal casing, to swing round freely. APPARATUS FOR CREATING UNDERCUT ANNULAR CAVITIES AT THE BOTTOM OF DRILLED HOLES MADE IN ANY KIND OF SURFACES, as per any of the previous claims, characterized in that the length of the said casing pieces (7) and (12) is such that their free ends are set at the same level and adjacent to the cutter (5) and at the same time, the distance between the said cutter (5) and the front area of the head corresponding to the external casing piece is in accordance with the depth of the hole on which the apparatus is to operate. APPARATUS FOR CREATING UNDERCUT ANNULAR CAVITIES AT THE BOTTOM OF DRILLED HOLES MADE IN ANY KIND OF SURFACES, as per any of the previous claims, characterized in that within the external casing piece (12) or optionally along a generatrix of the internal casing piece (7) a channel (23) is established for the cooling water, which flows out at the level of the cutter (5) and which at its opposite end is subjected to an external radial elbowing and opens into an annular chamber (30) located in the head of the said external casing piece, an annular chamber which is closed with the aid of an annular and complementary piece (25), and with the participation of seals (31), an annular piece in which the corresponding water inlet conduit (26) is established, and to which an elastic ring (28) is frontally related which slightly overlaps the front of this head (13) in which a frontal groove (29) is defined which converts into a chamber when the apparatus is coupled to a tightly closed surface, with the aid of the said elastic ring (28), to which chamber an outlet pipe is attached and to which the cooling water accedes, removing the debris produced by the cutter through a channel established between the external casing piece and the wall of the drilled hole, which is produced by a rebate made in the external annular piece, along one of its generatrixes, the said rebate being located in front of the arc which the shaft of the cutter describes when the external casing piece remains stationary, and the internal casing piece is rotated.

Inventors: SANCHEZ VELASCO, VICENTE
Applicants: SANCHEZ VELASCO, VICENTE
Application year: 1986
Main classification: B28D1
IPC codes: B23B35, B23B41, B23B51, B28D1