Wallpaper steamer

Abstract: The steamer for use in stripping wallpaper comprises a housing (1) accommodating a water tank (2), an electronically heated steam generator (3) and an electric pump (7) for pumping water from the tank to the steam generator (3). The steamer also has a base portion (4) with a peripheral wall (5) and forming a steam chamber (6) to which steam is supplied by the steam generator (3). The water tank (2) has a water capacity of substantially 400cc. The electric heating element has an electrical rating of 1.2 Kw. The pumping rate of the pump (7) to is about 25cc/minute. These values allow a user to use the steamer for about 20 minutes before the water tank (2) needs filling.

Description: This invention relates to hand-held wallpwper steamers for use in stripping wallpaper and other coverings secured to a surface by heat and/or moisture softenable adhesive. Such steamers have been proposed before but they have not been entirely satisfactory from the point of view of a home user. In the case of hand-held steamers with an "on-board" water tank, it is sometimes found that, because of the large water capacity of the tank that is needed to allow the steamer to be used for an acceptable period time, the steamer is very heavy and soon tires the user. If the water capacity of the tank is reduced, the period of use may be unacceptably shortened. In some steamers, steam is produced by boiling water in the water tank. In such cases, the rate of production of steam is not controlled and this also affects the period of time for which the steamer can be used. In most cases, water is heated by an electric heater to produce steam and the electrical rating of the heater also affects the period of time for which the steamer can be used. The electrical rating of the heater must also be such that the steamer can be powered from a domestic power supply. It is known from US Patent No. 1,518,454 to provide a wallpaper remove provided with a reservoir to contain water with a heater for generating steam and a frame for supporting perforate tubes in communication with the reservoir or steel boiler to apply the steam under pressure to the paper, and means for packing the edge of the frame so that the steam will be localized, thereby obtaining greater efficiency than would be possible if the steam leaked to atmosphere. It is further known from French Patent No. 2,368,862 to provide a steam iron comprising a water container and an electrically driven pump to deliver water from the container to a steam can be generated simultaneously. There are, thus, a number of conflicting requirements that have to be reconciled and it is thought that this has not been achieved hitherto in a hand-held steamer because there is no satisfactory steamer on the market. Surprisingly, it has been found that it is possible to reconcile the conflicting requirements in an acceptable manner. In one embodiment of the present invention, a hand-held wallpaper steamer comprises a housing with a base portion with a depending peripheral wall and forming an open-faced steam chamber, a refillable water tank accommodated in the housing and having a water capacity of substantially 400 ccm, a steam generator having steam exits and accommodated within the housing and having an electric heating element rated at substantially 1.2 kW for heating the steam generator, steam exits from the steam generator communicating with the steam chamber, and an electrically powered water pump located in the housing, connections from the tank to the pump and from the pump to the steam generator to allow the pump to pump water from the tank to the steam generator, the pump having a pumping rate of about 25 ccm/min., the arrangement providing about 20 minutes use of the steamer before the tank needs refilling. By controlling the rate of flow of water into the steam generator, it has been found possible to reduce the water capacity of the water tank, electrical rating of the heater heating the steam generator and thus the physical size of the steam generator and thereby provide a steamer that is comfortable to hold for a considerable period of time and can be powered from a domestic power supply. An embodiment of the invention will now be described in greater detail with reference to the accompanying drawings of which: Figure 1 is a perspective view from the front, one side and above of the embodiment, Figure 2 is a perspective view similar to that of Figure 1 but with one part shown separated from the remainder of the embodiment, Figure 3 is a schematic perspective view from one side with a part removed to reveal the position of certain internal components, Figure 4 is a general assembly sectional view of the embodiment, Figures 5 and 6 are, respectively, a view from above and a view from below of a part of the housing of the embodiment, Figures 7 and 8 are, respectively, a section on the lines XV and XVI of Figure 5, Figure 9 is an underneath view of another component of the embodiment, Figure 10 is a plan view of the component of Figure 9 with part removed, Figures 11, 12 and 13 are, respectively, sections along the lines XIX, XX and XXI of Figure 10, Figure 14 is a side view of a part of the component of Figure 9, Figure 15 is a plan view of the component of Figure 9, Figure 16 is a section on the line XXIV of Figure 15, Figures 17 and 18 are, respectively, a plan view of another component and a section on the line XLI of Figure 17, and Figure 19 is a side view, partly in section, of a further component of the embodiment. The embodiment now to be described is suitable for steaming wallpaper prior to stripping the paper with a conventional stripping knife. However, the embodiment may also be used when stripping other surface coverings secured to the surface by heat and/or moisture softenable adhesives. The embodiment comprises a hand-held steamer with an "on-board" water supply that is replenishable by a user as necessary. As can be seen from Figures 1, 2 and 3, the embodiment includes a housing 1 contoured to accommodate a detachable water tank 2, a steam generator 3 and a base portion 4 with a peripheral wall 5, thereby forming a downwardly-open (as viewed in Figures 1, 2 and 3) chamber 6, hereinafter referred to as a steam chamber. Water from water tank 2 is pumped into a water chamber in the steam generator by an electrically powered pump shown diagrammatically at 7. Energisation of pump 7 is controlled by an electric switch 8 operated by a rocker arm 9. Steam from the steam generator 3 leaves the latter via exit holes in its lower face and emerges into the steam chamber via connectors described below. The housing 1 includes a central portion 10 which extends away from the base portion 4 and has a forward projection 11 beneath which the water tank 2 is located on a flat part 12 of the housing 1. Extending rearwardly from the uppermost part of portion 10 is a handle 13 of generally cylindrical shape and which terminates in a flat end 14 of triangular shape and which is part of the housing 1 thereby forming a handle of a closed loop configuration. The cross-sectional size of the handle 13 in a plane transverse to its length is much smaller than that rear face of portion 10 from which the handle 13 extends. As can be seen, the upper surface (as seen in Figs. 1, 2 and 3) of projection 11 is contoured as at 15 to accommodate the rocker arm 9 that operates the switch 8. Located in the forward projection 11 of the housing 1 is a catch 16 for retaining the water tank 2 in the position in which it is shown in Fig. 1. As will be explained in more detail below, catch 16 can be actuated by a user to release the water tank 2 prior to detaching the tank from the housing. The catch 16 is so contoured that it is displaced by the tank 2 on initial movement of the latter into the position shown in Fig. 1. On final movement of the tank 2, the catch 16 automatically returns to a tank retaining position. The housing 1 has, on both sides, air holes 17 which allow air to circulate within it so limiting heat transfer from the steam generator 3 to the housing 1. The water tank 2 is of generally cubic form but is contoured to blend in with the contours of the housing 1 when in position thereon. The upper wall 21 of the water tank 2 has a filler hole 22 normally closed by a removable stopper 23. The upper wall 21 also has a rectangular recess 24 which cooperates with catch 16 to retain the water tank in position on the housing 1. The rear wall 25 is recessed as at 26 to accommodate a connector 27 forming part of a water inlet tube 28 inside the water tank 2 and described in more detail below. The connector 27 automatically engages with a short nozzle 29 of pump 7 in the portion 10 of the housing 1 as the water tank 2 reaches its fully home position on the housing. The nozzle 29 is the output nozzle of pump 7 as will be described in more detail. The output of pump 7 is joined by a connector tube 30 to an inlet 31 of the steam generator 3. The housing 1 is of clam shell construction and is formed by two clam shells 18 and 19 which abut along a vertical fore and aft plane through the middle of the steamer. The line is indicated at 20 in Figures 1, 2 and 3. The clam shells 18, 19 are moulded from a suitable plastics material for example talc filled polypropylene and are contoured on one face - the inner face - to support the components mounted inside the housing formed when the clam shells are placed together. The clam shells 18, 19 are generally similar as regards their external faces, each providing one half of the following parts of the housing 1 - central portion 10, the forward projection 11, the flat part 12, the handle 13 and the flat end 14. The base portion 4 of the embodiment is shown in Figures 5, 6, 7 and 8 and is of generally rectangular form when seen in plan as in Figures 5 and 6. The base portion 4 which is of a plastics material, for example a glass fibre reinforced thermosetting polyester, or a thermoplastic polyester which is preferably glass fibre reinforced, has the peripheral wall 5 whose external shape is contoured as at 63 to merge smoothly with the lower surface of the clam shells 18 and 19 when those parts are assembled together. Located within the housing 1 above the floor 64 is the steam generator 7 and this is shown in more detail in Figs. 9 to 16. As can be seen from Fig. 9 , the steam generator 3 is of generally rectangular form when viewed from above. The generator has a body 85 of a heat conductive metallic light alloy. Projecting from the ends of the body 85 are mounting ears 86 apertured to receive mounting screws (not shown). Cast integrally with the body 85 is an electric heating element 87 of the sheathed, resistance kind and shown in Fig. 14. The ends of the element are indicated at 88 and the path followed by the element is indicated in dotted lines 89 in Fig. 9 . As can be seen, the element is looped at one end, the body 85 being locally increased in thickness at 90 to accommodate the loop and other parts of the length of the element. The upper (as seen in Fig. 10) face of the body 85 is channel led as will be described below and has a central recess 91 that accommodates a thermally responsive element 92 in good thermal contact with the body 85. The upper face of the body 85 is covered by a cover plate 92 apertured at 93 to give access to the element 92 and at 94. The plate 92 is slightly recessed round the aperture 94. The cover plate 92 is secured to the body 85 in a manner described below. The channelling in the upper face of the body 85 is seen in Fig. 10. The face has a water receiving chamber 95 of circular form when seen in plan as in Fig. 10 . The water chamber 95 is located beneath aperture 94 of plate 92. From diametrically opposed positions on the chamber 95 extend passages 96, 97 of serpentine elongate form which are mirror images of each other. The passages 96, 97 terminate in common areas 98, 99 respectively. From the common areas 98, 99 extend further serpentine elongate passages of which two 100, 101 lie along the sides of the body 85 and pass to the right hand (as viewed in Fig. 10) side of the water chamber 95 where they join a common transverse passage 102. In the centre of the transverse passage 102 is a steam exit 103 and while other steam exits 104 are located in the vicinity of the junctions with the transverse passage 102 of the passages 100, 101. Also extending from the common areas 98, 99 are further passages 105, 106 which after merging at 107 diverge in opposite directions to join a common transverse passage 108. In the centre of transverse passage 108 is a further steam exit 109 whilst other steam exits 110 are located in the vicinity of the junctions with the transverse passage 108 of the passages 105, 106. The distances from the common areas 98, 99 along the passages 100 and 101 to the steam exits 104 and along the passages 105, 106 to the steam exits 110 are substantially equal. As can be seen from Fig. 18, the steam exits 103, 104, 109 and 110 are at the upper ends of respective nozzles 111 formed in the body 85 and that project downwardly from the lower face of the body 85. The locations of the nozzles 111 correspond with those of the nozzles 70 and 76 of the floor 64 of the base portion 4. The looped end of the heating element 87 is located in the general area beneath water chamber 95 thereby ensuring a high heat input to this area sufficient to "flash" water entering the chamber into steam. The lengths and depths of the passages 96, 97, 100, 101, 102, 105, 106 and 108 are such as to provide surface area sufficient to ensure further heating, and therefore drying, of the steam exitting from water chamber 95. The physical mass of the body 85 is related to the electrical rating of the heating element 87 and is such that the latter is able quickly to bring the body 85 to a working temperature. The nozzles 111 provide a slight restriction on the flow of steam from the generator so that steam at the steam exits 103, 104, 109, 110 are at a pressure slightly above atmosphere. Forming the passages and chambers in the same face of the body 85 facilitates manufacture as does the configuration shown of the passages. Fig. 15 also shows that the thermally responsive device is held in the recess 91 by a metal strap 112 secured in place in a manner described below. The device responds to the temperature of the steam generator and operates to keep the latter at a controlled temperature. Joined to the terminals of the device 92 are electrical conductors 113, 114 of which conductor 114 includes a thermal cut-out 115 to protect the steamer generator against over-heating. Conductor 113 is connected to an electrical terminal 116 mounted upon an extension 117 of the base 85 and insulated therefrom. The water tank 2 is shown in more detail in Figures 17 and 18. As described above, the tank 2 is of generally cubic form and has front and side walls 148, 149 contoured to blend in with the contour of the housing 1. The upper wall 21 of the tank, which is inset slightly with respect to the upper edge of the front and side walls, slopes downwardly towards the rear wall 25 of the tank and has the filler hole 22 and the recess 24. The rear wall 25 is also slightly inset with regard to the rear edges of the side walls 149 has longitudinal recesses 26 referred to above which accommodates the connector 27 and allows the remainder of the rear wall to be located in close proximity to the adjacent face of the portion 10 of the housing when the tank is correctly positioned on the housing 1. The connector 27 locates in a hole 150 in the recess 26. Preferably, the tank walls are made of a clear plastics material so that a user can readily observe the volume of water in the tank and replenish it when necessary. The floor 151 of the tank is also slightly recessed with respect to the lower edges of the front and side walls but it extends beyond the rear wall 25 as shown in Figure 18. The visual appearance of the tank 2 is enhanced by shaped depressions 152 in the side walls 149, such depressions serving also to impart a greater degree of rigidity to the side walls. The depressions also enable a user to grasp the tank more easily when withdrawing it from the housing. As has been referred to above, tank 2 is retained in position in the housing 1 by a releasable catch 16. Figure 19 shows the pump 7 in more detail. The pump has two principal body parts 165 and 166 each with cylindrical end portions 167, 168 respectively. Body part 165 has a central tubular extension 169 that houses a cylindrical core 170 of soft iron biassed by a coiled spring 171 in a downwardly direction as viewed in Figure 19. Surrounding the extension 169 and supported by the end portion 167 is a coil shown diagrammatically as block 172. The two ends of the coil are joined to respective electrical connectors one of which is shown at 173. The adjacent faces of the end portions 167, 168 have central recesses of similar size and which house, respectively, a flexible diaphragm 174 and a cup shaped fitment 175. The diaphragm has a central aperture 176 which allows a head 177 on the core 170 to be inserted into a space within a central extension 178 of the diaphragm 174 thereby securing the latter to the core. The diaphragm also has a peripheral wall 178 that seats in a corresponding annular recess in the upper edge of the cup shaped fitment 175. The fitment 175 has a tubular extension 179 that locates in a passageway 180 in body part 168. The passageway 180 is stepped as at 181 and seated upon the step is the collar 182 of a duck-bill valve 183. The duck-bill valve 183 extends upward (as viewed in Fig. 45) into the extension 179 and terminates just below a hole 184 through the base of the fitment 175. The duck-bill valve 183 is orientated to allow flow in an upward direction only as indicated by the arrow. Passageway 180 extends through a lateral extension 185 of the body part 166 and forms the pump inlet 29. Body part 166 has a second passageway 186 as shown and this accommodates a second duck bill valve 187 with a flange 188 at one end, the flange being seated upon a recessed shoulder 189 at the upper end of passageway 186. Passageway 186 terminates in a hole 190 through the base of the fitment 175. Duck-bill valve 187 is orientated to allow flow in a downward direction only as indicated by the arrow. Passageway 186 terminates in a downwardly extending nozzle 191 which forms the pump outlet. During manufacture and prior to placing the components in the housing, it is necessary first to assemble the steam generator. The thermally responsive device 92 is placed in the recess 91. Cover plate 92 is placed in position on the body 85 so that studs 192 extending from the upper face of the body pass through corresponding holes in the cover plate and hole 93 register with device 91. The tops of the studs 192 are then peened over to secure the cover plate 92 to the body 85. Two of the studs 192 are so located that they pass through holes in the metal strap 112 so securing the latter and thus the thermally responsive device 92 in position. The conductors 113 and 114 are then electrically secured to the terminals of the device 92 and positioned as shown in Fig. 23. Conductor 113 is electrically joined to terminal 116 by a suitable jointing tag. Finally, the flexible connector 30 (Fig. 4) is attached to the cover plate 92 by locating the edge surrounding the hole 94 in a channel 194 in the head 195 of the connector. The connector 30 is joined to the pump outlet 191 as will be described below. To assemble the components described above in the housing 1, the rocker arm 9 is located in the cut away 35 in clam shell 18, the bosses 134 being positioned in the semi-circular recess 34. The inclined surfaces 130 of the rocker arm 9 are accessible to a user through the cut away 35, and pivotal movement is limited by the flanges 132 which locate within the clam shells. The switch 8 is then seated in the recessed portion 33A of the rib 33 with the switch terminals pointing towards the cable outlet 42 and the rocker 127 lying in the path of the extension 135 of the rocker arm 9. The pump 7 is located in the compartment above the rib 37 with the nozzle 191 pointing downward (as viewed in Fig. 4) and the outlet 29 extending through the adjacent wall of the clam shell 18 via recess 47. In this orientation, the electrical connectors 173 are positioned just below the horizontal part of rib 33. Tank catch 16 is secured in place by inserting the tubular support 153 over the bearing stub 39 so that the serrated surface 164 is accessible through cut away 41 and the hooked end 163 engages the nose of the clam shell 18 adjacent the cut away, i.e. the catch 16 is in the position shown in Fig. 4. The assembled steam generator 3 is then mounted upon the base portion 4. With the base portion in the position shown in Fig. 5, a gasket seal/connector 118 is placed over each of nozzles 70 and 76, the interconnections 120 being pressed over the nozzles 70 and 76, and the gasket portion 121 seating on the boss 68. The steam generator 7 is then placed in position with the ears 86 seated upon the bosses 68. In so doing, the nozzles 11 of the steam generator engage into the interconnections 120. Screws are then entered through the ears 86 and screwed into the bores in the bosses 68 to secure the steam generator to the base portion 4. The base portion is then engaged with clam shell 18, the stepped edge 65 engaging with the correspondingly stepped edge 46 of the clam shell. These parts are secured together by screws passed upwardly through the bores of two of the bosses 24 and screwed into the bores of bosses 49 in the clam shell. After the base portion 4 has been secured to clam shell 18, the connector 30 (Fig. 4) is pushed on to the outlet nozzle 191 of the pump 7. A neon indicator lamp 197 is located in the recesses 57 in the clam shells 18, 19 and electrical connections are completed between the terminals of the switch 8, terminals of the neon lamp 197, the terminals 88 of the heating element 87 and the conductors of the power lead 198 (Figs. 3 and 4) so that when the latter is connected to a power source, element 87 is energised and the neon lamp lights to indicate energisation, and so that movement to its 'ON' position of the rocker 9 operates switch 8 to its 'ON' position and the coil of the pump is energised. Connected in series with the power supply to the pump is a half wave rectifier, for example a diode (not shown). The second clam shell 19 is then placed in position on clam shell 18 and the base portion 4 and secured in place by screws passed upwardly through the bores in the remaining two bosses 74 in the base portion, and other screws passed through apertures 59A in clam shell 19 and into bores in bosses 59 in the other clam shell 18. The water tank 2 is now assembled by securing the filter 147 in the recess 146 of fitment 144 and the latter is attached to the water outlet tube 28. The fitment 144 and the tube 28 are inserted through hole 150 in the rear wall 25 of the water tank 2 and connector 27 is pressed firmly into the hole. The inset top and rear wall 21, 25 of the water tank 2 allow the edges of the front wall 148 and side walls 149 to locate closely adjacent to the flanges 32B and those edges to blend with the bevels 32A can be seen, for example, in Fig. 1. To use the appliance, tank 2 is filled with water via the hole 22 in the upper wall 21 of the tank 2 and the hole closed by the removable stopper 23. The tank 2 is next placed in position on the housing, care being taken to ensure that the projecting extension 29 of the pump 7 passes through the lip 142 and into the connector. As the tank 2 is placed in position, the upper wall 21 of the tank comes into contact with the bevelled face 160 of the projection 159 and displaces it by flexing the lower part of the wall 157. As the tank reaches its final position, projection 159 snaps into recess 24 to hold the tank 2 in position in the housing 1. The power lead is then connected to a source of power and the neon lamp glows indicating that element 87 is energised. The user allows a short time for the steam generator to reach a working temperature and then rocker arm 9 is actuated to its 'ON' position so operating switch 8 and energising the pump. The rounded contour of the extension 135 facilitates operation of the rocker 127 of the switch 8 as the rocker arm 9 pivots on the bosses 134. Energisation of coil 172 draws the core 170 upwardly as seen in Fig. 19, against the action of spring 171. Diaphragm 174 is flexed upwardly and draws in water from the tank 2 via filter 147, connector tube 28, inlet 185 and duck bill valve 183. Coil 172 is then de-energised and spring 171 forces the core 170 downwardly so flexing diaphragm 174 downwardly and expelling water through duck bill valve 187 and outlet 191. Energisation and de-energisation of the coil occur at about 25 cycles per second and this gives a continuous floor of water whilst the pump is operating. Water is pumped via connector 30 into chamber 95 where it is flashed into steam by the heat of the body 85. The generated steam flows along passages 96 and 97 to intermediate areas 98, 99 and thence to the outlet nozzles 70 where it emerges into the steam chamber 6 and rapidly fills the latter. The serpentine passages between the water chamber 95 and the nozzles 70 allow the steam to be dried so that by the time it exits from the nozzles, the moisture content is very low. At this stage, the base portion is placed against an area of wallpaper to be stripped, the edge of the peripheral wall 62 being pressed against the wallpaper. Steam confined in the chamber permeates through the wallpaper and rapidly softens the adhesive holding the wallpaper in position. The steamer is then moved to an adjoining area of wallpaper while the user scrapes off the wallpaper covering the area. It is not necessary to maintain the pump energised continuously, the user may return the rocker arm to its 'OFF' position during movement of the steamer from one area of wallpaper to another. The water capacity of the tank 2 in conjunction with the rating of the heating element 85 and the pumping rate of pump 7 is such that the steamer can be used for about 20 minutes before the tank 2 needs refilling. The pumping rate is about 25 ccm/min. A water tank capacity of about 400 ccm in conjunction with a heating element rated at 1.2 kilowatts provides the time just referred to. The mass of the steam generated in conjunction with a heater of the rating mentioned vaporises water feed into chamber 95 and heats the vapour to a temperature of 120°C nominal measured in the chamber 6. Steam from the nozzles 70 enters the chamber at a pressure sufficiently high to ensure that the chamber 6 is quickly filled with steam and kept filled. This action is assisted by the recessed areas 82 and 83. The parameters just referred to allow the steamer to be of a size and weight that can be conveniently hand-held and used without excessive strain on the user. In addition, for an average wallpaper, the time that the user takes to strip an area that has just been steam treated is about equal to the time that the steamer takes to soften the adhesive in that area. The rating of the heater also means that the steamer is suitable for use in domestic premises. It will be appreciated that the bulk of the steam generator 3 is spaced from the floor 64 of the base portion 4. The ears 86 by which the generator is mounted upon the bosses 68 are thermally insulated by the parts 121 of the gasket seal/connector while the connectors 120 are interposed between the nozzles 111 of the steam generator and nozzles 70 and 76 in the floor 64 of the base portion. This ensures that the base portion which is accessible to a user always remains at a relatively low and safe temperature whilst it is in use. The steamer is normally used with the water tank 2 uppermost and in that position, it will be observed, for example from Fig. 4, that the steam generator 3 is located towards the lower end of the steam chamber 6 and that is a greater distance between the upper side of the steam chamber and the upper of the nozzles 70 and 76 than between the lower edge of the steam chamber and the lower of the nozzles 70 and 76. This siting of the generator relative to the steam chamber improves the distribution of steam in the chamber. The steamer can also be used in the removal of paper from ceilings. In that case, the chamber 6 is uppermost. Any condensation that forms on wallpaper during the steaming of an area of wallpaper on a ceiling tends to fall into the steam chamber where it collects in the gutter 66. The condensation may be discharged from the gutter 66 by simply returning the steamer to an upright position and allowing the condensation to run away.

Claims: A hand-held wallpaper steamer for use in wallpaper stripping comprising a housing (1) which accommodates a base portion (4) with a depending peripheral wall (5) and forming an open-faced steam chamber (6), a refillable water tank (2) accommodated in the housing (1) and having a water capacity of substantially 400 ccm, a steam generator (3) having steam exits (103, 104, 109, 110) and accommodated within the housing (1) and having an electric heating element (87) rated at substantially 1.2 kW for heating the steam generator (3), steam exits from the steam generator (3) communicating with the steam chamber (6), and an electrically powered water pump (7) located in the housing (1), connections from the tank (2) to the pump (7) and from the pump (2) to the steam generator (3) to allow the pump (7) to pump water from the tank (2) to the steam generator (3), the pump (7) having a pumping rate of about 25 ccm/min, the arrangement providing about 20 minutes use of the steamer before the tank needs refilling. A hand-held wallpaper steamer according to claim 1 characterised in that the steam generator (3) has a water chamber (95) for receiving water to be turned into steam, and elongate passages (96, 97, 100, 101, 102, 105, 106, 108) lead from the water chamber to the steam exits, and the electric heating element (87) heats both the water chamber and the elongate passages.

Inventors: WILKINS PETER RAVENSCROFT, WILKINS, PETER RAVENSCROFT
Applicants: BLACK & DECKER INC, BLACK & DECKER INC.
Application year: 1987
Main classification: B44C7
IPC codes: D06F75, B44C7, F22B1