AEROPLANE WINDOW POLISHING DEVICE

Abstract: An automatic polishing device for automatic smooth polishing of windowpanes from the outside of an aeroplane without the necessity of removing them from the aeroplane. The device comprises with replaceable petal-shaped polishing pads (10) equal in number to the number of polishing steps required such as, rough, medium and finish polishing. Each pad is mounted on the exterior wall surface of an aeroplane and urged against the window surface with substantially constant pressure and is supplied with liquids for polishing and washing from a centally-disposed opening (9c).

Description: The present invention relates to a window surface polishing device for aircraft. For safety's sake, aeroplane windows are made of difficult-to-break hard glass or hard acrylic resin and double-structured. During high-speed flights, however, the outside window is bombarded with and abraded by fine particles and dust in the air, and hence inevitably suffers from "scratches" and "crevice-like cracks extending into the inside of the windowpane", commonly referred to as crazing, which obstruct the view from the window and give rise to diffuse reflection of sunlight. It is customary, at present, to polish and smooth window surfaces at regular intervals for customer's satisfaction. This polishing is done by hand, as aeroplane windows are curved, unlike those of ordinary buildings, and are difficult to polish automatically. Further, not only are aeroplane windows large in number but also are double-structured, as mentioned above, and cannot be removed from the outside of the aeroplane body. Therefore, the polishing must be done, for instance, in the following steps of: (1) removing seats near each window; (2) removing the inner wall around the window; (3) taking the window frame down and removing the inside windowpane; (4) taking out the outside windowpane; (5) carrying the outside windowpane into a polishing workshop and polishing it by hand using a motor-driven polisher or the like; and (6) taking the polished windowpane to the plane and fitting it into the window by reversing the procedures (1) to (5) outlined above. However, this method is troublesome and time-consuming, and hence is extremely disadvantageous for the operation of aeroplanes. In addition, handwork sometimes causes insufficient finish such as uneven surfaces so that it may shorten the lifetime of the windowpane due to overgrinding or the like. Much skill is required for uniform polishing causing a marked increase in polishing costs. DE-A-2645405 describes an aircraft window polishing device for use in a workshop. Windows are removed from the aircraft and mounted in a polishing apparatus; and a polishing pad is then automatically driven in predetermined paths across the window surface. An object of the present invention is to provide an automatic polishing device which is intended to avoid the above-mentioned defects of the prior art method and which provides automatic smooth polishing of windowpanes from the outside of an aeroplane in a far shorter time and with far less labour than hand polishing without the necessity of removing them from the aeroplane. According to the present invention there is provided an aeroplane window polishing device comprising polishing means having a polishing pad for polishing a window surface of an aeroplane, means for supplying polish and cleaning liquids to the polishing means and means for urging the polishing pad of the polishing means against the window surface to be polished, characterised in that the polishing means is a rotatable polishing means, and that the aeroplane window polishing device further comprises means for moving the polishing means in X- and Y- axis directions on a plane perpendicular to the rotational axis of the rotatable polishing means while rotating it, and means defining a frame and detachably mountable to an outer surface of the aeroplane for detachably mounting the rotating polishing means within said frame to the outside of the aeroplane body opposite the window surface. A preferred embodiment of the present invention comprises replaceable petal-shaped polishing pads of the same number as a required number of polishing steps such as rough, medium and finish polishing. The polishing device is for mounting on the exterior wall surface of an aeroplane, a polishing pad being urged against the window surface with substantially constant pressure, and being supplied with liquids for polishing and washing from a centrally-disposed opening. Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings; in which: Figs. 1A and 1B are diagrams showing ranges of polishing employed in an embodiment of the present invention; Figs. 2A, 2B, 2C, 2D and 2E are diagrams illustrating the loci of movements of polishing pads employed in an embodiment of the present invention; Fig. 3 is a perspective view of a mounting device of an embodiment of the invention; Fig. 4 is a perspective view showing its principal part on an enlarged scale; Fig. 5 is a perspective view of a polishing device of an embodiment of the invention; Fig. 6 is an enlarged perspective view of its principal part; Figs. 7A, 7B and 7C are a perspective and a sectional view of a polishing pad and a polishing head of an embodiment of the invention; Figs. 8A and 8B are perspective views of a polishing pad housing box of an embodiment of the invention; and Fig. 9 is a perspective view showing the state of an embodiment of the invention during polishing. Principles of embodiments of the present invention will first be described. By way of example, during rough polishing the central area of the windowpane is polished most deeply as indicated by A in Figs. 1A and 1B; during medium polishing the windowpane is polished over an area wider than that of rough polishing as indicated by B; and during finish polishing the windowpane is polished over the entire area of its surface as indicated by C. In each polishing step, the pad is moved first along such a rectangular path from a start S to an end E as shown in Fig. 2A, then in the Y-axis direction along U-shaped paths as shown in Fig. 2B which provides easy scanning control and avoids incomplete scanning of the intended area, then along U-shaped paths shifted by a 1/2 pitch from those shown in Fig. 2B and in the reverse direction of stroke therefrom as shown in Fig. 2C, then in the X-axis direction along U-shaped paths as shown in Fig. 2D, and then along U-shaped paths shifted by a 1/2 pitch from those shown in Fig. 2D and in the reverse direction of stroke therefrom as shown in Fig. 2E. This is intended to attain the following advantages: One advantage is to prevent traces of polishing from remaining unremoved after rough, medium and finish polishing, simplify the scanning of the window surface for polishing and ensuring complete polishing of the entire area of the window surface through sequential enlargement of the range of polishing by the rough, medium and finish polishing pads (such as shown in Figs. 1A and 1B), particular movements of the polishing pads (such as shown in Figs. 2A to 2E), and use of a constant contact pressure for all the pads. By this means, uniform and smooth polishing of the window surface, which is impossible with conventional rotation type polishing, swing type polishing (just like wall plastering) and oscillation type polishing methods, can automatically be achieved easily by one or a small number of operators from the outside of an aeroplane, without involving the aforementioned troublesome, time-consuming work such as removal of window frames. A further advantage is to distribute polishing and cleaning liquids uniformly between the polishing pad and the window surface. This is preferably achieved through use of a petal-shaped pad which is supplied with the liquids from its central opening. This provides excellent lubrication and efficient suppression of heat generation between the polishing pad and the window surface, and hence permits an increase in the number of revolutions of the polishing pad, providing for enhancement of the polishing efficiency and affording a substantial reduction in the polishing time. Consequently, polishing costs of window surfaces can be markedly cut. Next, the present invention will be described concretely in connection with an embodiment. In. Fig. 3 showing a mounting device I, reference numeral 1 indicates a rectangular mounting frame, 2 handles and 3 a rectangular plate for positioning use, which has a centrally-disposed opening 3 a of a size slightly larger than a window frame a and is fixed to the back of the mounting frame 1. Reference numeral 4 designates vacuum suction pads, which are provided at four corners on the back of the mounting frame 1 and stick fast to the surface of the aeroplane body by suction force produced when urged against it, or by suction with vacuum pumps (not shown), whereby fixing the mounting frame 1 to the surface of the aeroplane body. Reference numeral 5 designates holes, which receive support projections 6 b of a polishing device II described later and are made in the mounting frame 1 at its four corners in correspondence with the positions of the support projections 6 b . For example, as shown in Fig. 4, a locking lever 5 b , which is adapted to be projected by a spring 5 a into each hole 5, engages a recess 6b₁ of support projection 6 b inserted into the hole 5, locking the polishing device II. The polishing device can be unlocked by pulling back the locking lever 5 b . In Fig. 5 which shows the polishing device II, reference numeral 6 indicates upper and lower support members coupled by right and left handle bars 6 a and each provided with the support projection 6 b which is inserted into the hole 5 of the mounting device I for locking thereto the polishing device. Reference numeral 7 designates a motor for driving a polishing head and 8 a rectangular frame-like motor support plate. The motor support plate 8 is received at its opposite end portions, through bearings, in straight X-axis guide grooves 6 c cut in the inner surfaces of the upper and lower support members 6 and is driven laterally by a reversible motor (not shown) fixed on a lower support plate 6 d through a rack which engages with a screw shaft driven by the motor and fixed on the support plate 8. In the opposite inner frames of the motor support plate 8 there are provided Y-axis guide grooves 8 a which conform to the curvature of the window surface b smaller than the curvatures of window surfaces to be polished. Support bars 7 a of the motor 7 are movably supported in the guide grooves 8 a . Thus, the motor 7 is movable in the Y-axis direction, i.e. in the vertical direction by the reversible motor (not shown) fixed on the support plate 8 through the screw shaft, which is driven by the reversible motor, and a rack which is fixed on the side of the motor 7 and engages with the screw shaft. Further, provision is made for obtaining a substantially constant contact pressure by the aid of a spring 9 b and an elastic material 10 c of a polishing pad 10 regardless of the curvature of the window surface to be polished. Reference numeral 9 designates a polishing head. As shown in Fig. 7A, the polishing head 9 comprises a hollow coupling shaft 9 a which is slidably received on the rotary shaft 7 b of the motor 7 and pressed by a spring 9 b toward the window surface, and a polishing pad mounting base 9 e which is coaxial with the hollow coupling shaft 9 a and whose central opening 9 c communicates therewith. The surface of the polishing pad mounting base 9 e has pasted thereto magic cloth 9 d (known by a Trademark of "magic tape") for detachably receiving a polishing pad. In Figs. 7A, 7B and 7C, reference numeral 10 designates a polishing pad, which is composed of magic cloth 10 a , an aluminium support disc 10 b laminated thereon and having a centrally-disposed opening, and spaced-apart pad members 10 d laminated on the aluminium disc 10 b with buffer elastic material 10 c sandwiched therebetween, an opening coaxial with that of the aluminium disc 10 b being defined by the pad members 10 d centrally thereof, as shown in Fig. 7B. Magic cloths 9d and 10a are mutually engageable but readily separable from each other. One of the cloths consists of a fabric with hook shaped fibres on one surface while the other consists of a fabric having fibre loops on one surface which are releasibly engageable by the hooks. When the polishing device II is mounted on the mounting device I with the polishing pad detachably and coaxially mounted on the mounting base 9 e by means of the magic cloth 9 d and 10 a as shown in Fig. 7A, the polishing pad 10 is urged by the spring 9 b against the window surface b with a substantially constant pressure even during movement on the window surface. Moreover, water, water mixed with anti-freezing liquid during the winter season, water mixed with a detergent, water mixed with an abrasive, and other required liquids are supplied by a pump 11 b from a liquid tank 11 a to the hollow coupling shaft 9 a through a flexible pipe 11 and are distributed uniformly all over the window surface to be polished, through the central opening of the polishing pad 10 and the petal-shaped pad members. Turning back to Fig. 5, reference numeral 12 designates a polishing pad exchanging and housing holder, which has pockets 12 a , 12 b and 12 c provided side by side within the range, in which the polishing pad 10 carried by the motor 7 can move in the X-axis direction, for housing three rough, medium and finish polishing pads 10₁, 10₂ and 10₃ as depicted in Fig. 8A. The housing holder is provided at the lower end portion of the back of the square motor support plate 8 in parallel thereto. For example, after completion of rough polishing, the motor 7 and, consequently, the polishing pad mounting base 9 e is lowered with the coupling portion between the magic cloth 9 d of the base 9 and the magic cloth 10 b of the polishing pad 10 held against, for instance, a front panel 12a₁ of the pocket 12 a as shown in Fig. 8B, thereby removing the rough polishing pad 10 a from the base 9 and letting it fall into the pocket 12 a . The base 9 is then brought to the position of the pocket 12 b , for example, and lowered thereinto, thereby supporting the medium polishing pad 10 b on the base 9. In this manner, the polishing pads are selectively used according to the kind of polishing. In Fig. 5, reference numeral 13 designates a driving control circuit box, in which a sequence control circuit and a start/stop push button switch 14 and so forth are housed. The sequence control circuit is connected via cables to the motor of the polishing device and other required sections to send thereto command signals for performing in a predetermined sequence the driving of the pump for supplying a required liquid such as water to the polishing pad, the driving of the polishing pad rotating motor, the exchange of the polishing pad, and the driving of the X- and Y-axis direction moving motors for obtaining the locus of movement of each polishing pad described previously with regard to Fig. 2A to 2E and the range of polishing described previously with respect to Figs. 1A and 1B. The operations of the embodiment are as follows: (1) The frame 1 of the mounting device I is mounted on the surface of the aeroplane body through the suction pads 4 so that the opening of the positioning square plate 3 is aligned with the window frame a . (2) After this, the polishing device II with the handle bars 6 a gripped by hands is attached to the mounting device I with the support projections 6 b inserted into the holes 5 of the mounting device I, as shown in Fig. 9. (3) Then, the switch 14 is turned ON, by which the rough polishing pad 10₁ is mounted on the base 9 and driven for polishing in the manner previously described in conjunction with Figs. 1A and 1B and Figs. 2A and 2B, and then it is replaced by the medium polishing pad 10₂ for medium polishing. Following this, the medium polishing pad 10₂ is replaced by the finish polishing pad 10₃ for finish polishing and a cleaning liquid is supplied to the pad 10₃ for cleaning the polished window surface. (4) After polishing, the polishing device II and the mounting device I are taken down from the aeroplane body by reversing the procedure mentioned above. The present invention has been described above in connection with a particular embodiment. However the mounting device I and the polishing device II may also be formed as a unitary structure and the drive control circuit box 13 may also be attached thereto. A liquid shielding apron 11 c may also be provided to prevent the polishing and cleaning liquids from splashing about as shown in Fig. 7A. It is also possible to effect substantially automatic or semi-manual control by providing a work command switch for each step. Although in the above described embodiments, the polishing pad is used both for polishing and for cleaning, a cleaning pad may also be provided separately. In such an instance, the number of pockets of the pad holder 12 is four. As described above, according to the present invention, uniform and smooth polishing of aeroplane windows can be achieved by particular movement of the polishing pads along U-shaped loci, without damaging window frames from the outside of the aeroplane body, simply by mounting thereon the polishing device. Furthermore, liquids for polishing and cleaning are distributed uniformly throughout each polishing pad to provided a good lubrication and effective suppression of heat generation on the window surface being polished, so that efficient polishing can be achieved, producing an effect of substantially reduced the polishing time. According, as compared with the conventional method in which window frames are taken down from the inside of the aeroplane and windows are removed and then polished one by one by hand, a plurality of windows can be polished by one or a small number of operators without any skill. Thus, embodiments of the present invention overcome the defects of the conventional method and markedly cuts the polishing costs as a whole.

Claims: An aeroplane window polishing device comprising polishing means (9) having a polishing pad (10) for polishing a window surface of an aeroplane, means (9a) for supplying polish and cleaning liquids to the polishing means (9) and means for urging the polishing pad (10) of the polishing means against the window surface to be polished, characterised in that the polishing means (9) is a rotatable polishing means, and that the aeroplane window polishing device further comprises means (7) for moving the polishing means (9) in X- and Y- axis directions on a plane perpendicular to the rotational axis of the rotatable polishing means while rotating it, and means (I) defining a frame and detachably mountable to an outer surface of the aeroplane for detachably mounting the rotating polishing means, within said frame, to the outside of the aeroplane body opposite the window surface. A device according to claim 1, characterised in that the polishing pad (10) is composed of a plurality of petal-shaped unit pads (10d) spaced apart, forming an opening (9c) centrally thereof. A device according to claims 1 or 2, characterised in that the polishing pad (10) has a hollow support shaft (9a) communicating with the polishing pad for supplying the polishing and cleaning liquids thereto. A device according to any preceding claim characterised in that a plurality of polishing pads (10) are provided in correspondence with the number of polishing steps required. A device according to any preceding claim, characterised in that the rotatable polishing means (9) comprises a plurality of polishing pads adapted so that an area of polishing is gradually enlarged towards the window frame in the X- and Y- directions as the surface roughness is smoothened by switching the polishing pads. A device according to any preceding claim, characterised in that the device is adapted so that polishing means (9) moves along U-shaped loci in the X- and Y-axis directions and the pitch of its movement is within the radius of the polishing pad (10). A device according to any preceding claim, characterised in that the means (I) for defining a frame comprises a rectangular positioning plate (3) having therein a positioning opening (3a) larger than the frame of a window to be polished at a portion against which said polishing means abuts. A device according to any preceding claim, characterised in that the rotatable polishing means (9) further comprise a motor (7) with a rotary shaft (7a), a hollow coupling shaft (9a) slidably received on the rotary shaft, a spring (9b) coupled to the rotary shaft and the hollow coupling shaft to press the hollow coupling shaft (9a) toward the window surface being polished, and a mounting base (9e) of the polishing pad engaged with the hollow coupling shaft (9a).

Inventors: IKEGAYA, TOSHIAKI, KOYAMA, YASUMASA, MOMOSE, MINORU, SHIRAHATA, TAKASHI
Applicants: SINANO ELECTRIC CO., LTD,, YACHIYO MICRO SCIENCE INC
Application year: 1989
Main classification: B64F5
IPC codes: B24D9, B24D13, B24B19, B24B7, B08B1, B64F5, A47L1, B24B13