DRILLING DEVICE, PARTICULARLY FOR REMOVING A SPOT-WELDED PORTION

Abstract: A drilling device for removing a spot-welded portion which comprises a main body casing 1 having a chuck receiving holder 3, a U-shaped arm 13, an end of which is connected to a side portion of the chuck receiving holder 3, a grip handle 15 pivotally connected to the base shoulder portion of the U-shaped arm 13, a chuck thrusting arm 16 mounted integrally at an end of the grip handle 15, a chuck 5 having a drill fixed at a free end of the chuck 5, the drill 8 is faced to a free end of the U-shaped arm 13, and a chuck receiver 4 for receiving the chuck 5 slidably inserted into main body casing 1. The chuck 5 projects with rotation in the direction so as to be close to the free end of the U-shaped arm 13 according to the movement of the chuck receiver 4 by depression of the grip handle 15, the force of which is transmitted via the chuck thrusting arm 16. The drilling device further comprises a projection amount adjusting screw 19 for adjusting the amount of projection of the chuck 5.

Description: Drilling device for removing a spot-welded portion. The presert invention relates to a drilling device exclusive for removal of spot-welded portions for use in a sheet metal working. At present, rationalization for a variety of processes has been under way through extensive use of various devices, but in certain fields of industries, there are still some works which have not been subjected to such rationalization as yet. For example, in a panel replacement process which occupies a considerable amount of work in a sheet metal working for motor vehicles, conventional practices have been such that spot-welded portions are drilled or ground by the use of a straight fluted drill or candle-like edge drill. The known practices as described above, however, are very inefficient in operation, thus requiring a considerable skill and much time involved therefor. The object of the present invention is to provide a drilling device for the purpose of carrying out the drilling work during removal of spot-welded portions in an efficient manner, with simultaneous saving of labor. To accomplish the foregoing object, a drilling device for removing a spot welded portion, comprises a main body casing with a chuck receiving holder, fixed to the main body casing, a U-shaped arm, one end of which is connected to the chuck receiving holder, means connected to the U-shaped arm for moving the same relative to a drill, mounted at the free end of a motor driven chuck and faced to the free end of the U-shaped arm. In practice one end of the U-shaped arm can be connected to a side portion of the chuck receiving holder, a grip handle pivotally connected to the base shoulder portion of the U-shaped arm via a pivot pin, a chuck thrusting arm mounted integrally at an end of the grip handle, a chuck having a drill fixed at a free end of the chuck, the drill being faced to a free end of the U-shaped arm, a chuck receiver for receiving the chuck, slidably inserted into the main body casing, and a motor for rotating the chuck via a rotary shaft The chuck projects with rotarion in the direction so as to be close to the free end of the U-shaped arm according to the movement of the chuck receiver by depression of the grip handle, the force of which is transmitted via the chuck thrusting arm. The drilling device further comprises a projection amount adjusting screw provided at an upper back portion of the grip handle for adjusting the amount of projection of the chuck The device is also provided with a plate thickness adjusting screw fixed at the free end of the U-shaped arm so as to face to the tip portion of the drill. According to the present invention, any damages to the plate which is not required to be separated may be perfectly prevented. Furthermore, not only the place to be drilled is correctly grasped by the employment of the U-shaped arm, but also the cutting edge of the drill is stable without slipping, thus resulting in a prolonged service life of the drill, and therefore, the device of the present invention can be readily used even by beginners with safety in operations, and thus, contributes to an improvement of working efficiency to an extremely large extent. A detailed description of the invention will be made with reference to the accompanying drawings which are to scale. Like numerals designate corresponding parts in the several figures. Fig. 1 is a perspective view showing an entire construction of a drilling device according to the present invention; Fig. 2 is a side elevational view partly in section, showing on an enlarge scale, the drilling device of Fig. 1; and Figs. 3 and 4 are diagrams explanatory of - functions of the device of Fig. 1. Referring now to the drawings, there is shown, in Figs. 1 through 4, a drilling device according to one preferred embodiment of the present invention, which generally includes a main body casing 1 for the device, a rotary shaft 2 for a spindle air motor to be driven by compressed air supplied from an air compressor (not shown) which is incorporated in said casing 1, a chuck receiving holder 3 threadedly connected to a forward end ofthemain body casing 1, and a U-shaped arm 13 to be described later integrally fixed, at its base shoulder portion G, to an end of said chuck receiving holder 3. The drilling device further includes a chuck receiver 4 formed cylindrically, with the rear end portion thereof being slidably fitted into said chuck receiving holder 3 and said main body casing 1. On the other hand, the front end portion of the chuck receiver 4 is formed with a flange P for restricting said sliding movement within a predetermined distance, and also with an engaging groove H to be engaged with an engaging pin 17 of a chuck thrusting arm 16 to be described more in detail later. The chuck 5 has a bore 6 axially formed at a central portion in the rear end portion of the chuck 5 for fitting the rotary shaft 2 thereinto, and a slit k is formed therein to extend over a predetermined distance in the longitudinal direction thereof. Accordingly, it is so arranged that, when the rotary shaft 2 is fitted therein, a similar slit k' is formed also at the side of the rotaty shaft 2 confronting said slit k so as to engage both of the slits with each other through a key 7 into one unit for making it possible to transmit rotation of the rotary shaft 2 to the chuck 5 through the sliding movement thereof. Meanwhile, in the forward end portion of the chuck 5, a bore 9 is formed for receiving a drill 8 therein, while a plurality of rows of split grooves are formed in the longitudinal direction along said bore 9, with a male thread e being provided around its peripheral surface. Thus, upon insertion of the drill 8 into the bore 9, the drill 8 is tightened for securing by threadedly engaging a socket 10 from above. The drilling device is further provided wiht ball bearings 11 and 12 at its front and rear portions as is most clearly seen in Fig. 2. On the other hand, at the base shoulder portion G of the U-shaped arm 13 fixed to the side face of the chuck receiving holder 3, there is provided a pivot pin 14 around which a grip handle 15 is pivotally supported, and a chuck thrusting arm 16 is integrally mounted at the forward end of the grip handle 15, while an engaging pin 17 is provided at the lower end of said arm 16 for engagement with the slit H of the chuck receiver 4. The drilling device is further provided with a spring 18 for normally biasing the grip handle 15 in the opened state, and a projection amount adjusting screw 19 provided at an upper back portion of the grip handle 15. When the grip handle 15 is brought into a closed state against the force of the spring 18, the chuck receiver 4 is prevented from rotation to an extent more than necessary. through contact of the lower end m of the screw 19 with the starting end n of the base shoulder portion of the U-shaped arm 13. In the above operating procedure, the chuck thrusting arm 16 causes the chuck receiver 4 to be projected, together with the chuck 5, in a direction indicated by an arrow 25, and the amount of projection may be readily altered by properly adjusting a thread length Q1 of said adjusting screw 19 from above. On the other hand, there is also provided a plate thickness adjusting screw 20 which is threaded into the forward end of the U-shaped arm 13 so as to confront a tip of the drill, and which is to be preliminarily adjusted, in its distance Q2 up to a head R thereof, to a necessary predetermined length. In the above case, in accordance with the amount of projection of the chuck receiver 4 described earlier, setting of the cut-in depth by the drill 8, during the removal of spotwelded portions to be described later and thickness of the remaining plate following the cut-in, may be effected freely as desired. At the rear end portion of the drilling device, there is provided a lever 21 for opening and closing a valve, which is arranged to be depressed in the course of closure of the grip handle 15 so as to rotate the spindle motor accommodated within the main body casing 1 for consequent rotation of the drill 8. Upon releasing of the lever 21 from the depression by the opening of the grip handle 15, the spindle motor and the drill are automatically stopped. The drilling device according to the present invention has the constructions as described in the foregoing, and for actual use, thickness of the plate to be processed is preliminarily measured to properly adjust both. of the projecting amount adjusting screw 19 and the plate thickness adjusting screw 20 in advance according to the thickness of the plate thus measured. After completion of the above procedure, the device is applied to a spot-welded portion 22 by lightly holding the grip handle 15, and as the grip handle 15 is gripped more strongly, the chuck 5 advances in the direction of the arrow 25, while simultaneously, the lever 21 is depressed so that the drill 8 starts cutting into a plate 23 to be separated, while being rotated. In the above case, upon contact of the lower end m of the projection amount adjusting screw 19 with the starting end n of the base shoulder portion of the U-shaped arm 13 during the above cutting-in operation, the cutting-in is not effected any further, and the drill 8 is rotated in the fixed position only idly, and thus, any damages to the other plate 24 not required to be separated may be perfectly prevented (see Fig. 4). It should be further noted that, according to the drilling device of the present invention, not only the position to be drilled is correctly grasped by the employment of the U-shaped arm 13, but also the cutting edge of the drill is stable without slipping, thus resulting in a prolonged service life of the drill. The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims: CLAIMS 1. A drilling device for removing a spot-welded portion; comprising a main body casing with a chuck receiving holder, fixed to the main body casing, a U-shaped arm, one end of which is connected to the chuck receiving holder, means connected to the U-shaped arm for moving the same relative to a drill, mounted at the free end of a motor driven chuck and faced to the free end of the U-shaped arm. 2. A drilling device according to claim 1, in which one end of the U-shaped arm 13 is connected to a side portion of the chuck receiving holder 3; a grip handle 15 pivotally connected to the base shoulder portion of the U-shaped arm 13 via a pivot pin 14; a chuck thrusting arm 16 mounted integrally at an end of the grip handle 15; a chuck 5 having a drill 8 fixed at a free end of the chuck 5, the drill 8 is faced to an free end of the U-spaped arm 13; a chuck receiver 4 for receiving the chuck 5, slidably inserted into the main body casing 1; a motor for rotating the chuck 5 via a rotary shaft 2, the chuck 5 projects with rotation in the direction so as to be close to the free end of the U-shaped arm .13 according to the movement of the chuck receiver 4 by depression of the grip handle 15, the force of which is transmitted via the chuck thrusting arm 16; and a projection amount adjusting screw 19 provided at an upper back portion of the grip handle 15 for adjusting the amount of projection of the chuck 5, the tip of the projection amount adjusting screw 19 is connected with the base shoulder portion of the U-shaped arm 13 to restrict the projection amount of the chuck 5 by depression of the grip handle 15. 3. A drilling device for removing a spot-welded portion according to claim 2, wherein there is provided a plate thickness adjusting screw 20 fixed at the free end of the U-shaped arm 13 so as to face to the tip portion of the drill 8. 4. A drilling device for removing a spot-welded portion according to claim. 2 wherein there are provided a spindle air motor for rotating the chuck 5 via a rotary shaft 2; an air compressor for activating the spindle air motor; a valve provided at the air compressor, for supplying compressed air to the spindle motor in its open state; and a lever 21 for opening and closing a valve of the air compressor, the lever is depressed by the grip handle 15 to open the valve.

Inventors: TSUKAI, MICHIHARU
Applicants: MAEDA KIKO COMPANY LIMITED, TSUKAI, MICHIHARU
Application year: 1982
Main classification: B23Q5
IPC codes: B23Q5, B21J15, B25H1