GB2116905A - Domestic waste compactor - Google Patents

Abstract

A domestic waste compactor comprises a trolley 1 with drawer 5 and bin 8 located beneath ram 9 vertically movable by screw 10 acting in nylon block 11. Polymeric thrust washer 18, belt drive 15 and polymeric guides 30 all contribute to low-noise operation actuated by motor 13. Drawer portion 5 has side spacing wheels 68, side spacing guides, forward castor wheels 6 for selective location in dimples 71 to define a forward (compacting) location or in dimples 79 to define a rearward (filling) location, and rearward support wheels 7. <IMAGE>

Description

SPECIFICATION Domestic waste compactor This invention relates to domestic waste compactors.

Domestic waste compactors of the type referred to herein have a single vertical screw which rotates in a threaded nut secured to a vertically movable ram so as to force the ram on to, and retract it from, waste material held in a drawer member directly beneath the vertical screw.

Hitherto, domestic waste compactors of the type referred to above have tended to be noisy in operation and of expensive construction.

The noise arises from the transmission of vibrations from the moving parts, via the various bearings or guides, to the cabinet housing the drawer. This gives a consequential reinforcement of the noise and resonance at certain vibration frequencies.

Expense of construction can have a similar cause; hitherto, constructional features of domestic equipment have been related to prior existing large-scale industrial equipment used for compacting or baling and incorporating robust drive trains, elaborate metal housings and pressure-exerting linkages.

An object of the present invention is to provide a domestic compactor of the type referred to generally designed to possess drive train features for reducing noise-and vibration-generation and transmission and to possess a rationalised drawer and cabinet structure minimising operator noise and facilitating proper use.

In one aspect the invention provides a domestic waste compactor of the type referred to in which to resist the vertical thrust of the screw and to permit rotation thereof at least one slip thrust washer is interposed between means rotary with the screw and the underside of an upper thrust plate or of a member fixed in relation thereto. Such a slip thrust washer can be one or a stack of two or more discs, at least one of which is a polymer such as a polyamidebased polymer, optionally further containing molydenum disulphide solid lubricant. It can be interposed for example, around a continuing shank of the screw, which shank is guided for rotation in the thrust plate, and located between the hub of a wheel (integral with or attached to the screw) and the underside of the plate.

Such a slip thrust polymer washer can be used without additional lubricant. Optionally, however, it can be contained within a large-diameter recess in the hub and with its upper surface beneath the level of the hub surface and contacting a metal washer of generally the same diameter as the slip thrust washer. In such a case, the slip thrust washer can be additionally grooved or perforated. The hub recess can act as a reservoir for lubricant material, giving good lubricant access over an operating cycle as described in more detail below.

In another aspect the invention provides a domestic waste compactor of the type referred to having an internally-threaded nylon nut attached to the ram.

We have found that such a nut gives quiet operation over the lifetime of the equipment and adequate thrust for its use in a domestic context. Typically there can be used an integral cylindrical nut from 5 to 12 cms outside diameter, having an axial threaded bore of 2 to 5 cms diameter, apertured for attachment by suitable bolts to the ram.

In another aspect there may be provided a ram of square or rectangular horizontal cross-section, movable vertically at a clearance in a surround defining a similarly square or rectangular opening and isolated from direct contact with the surround by corner spacer members in the opening formed of lowfriction synthetic polymeric material such as the polyamide materials discussed above. A preferred type of spacer is an integral molding having parallel end faces (for accommodation at top and bottom faces of the surround) separated by a shank Lshaped in horizontal cross-section.

The surround can support at the said top face elastomeric buffer material to hold projecting ram portions from contact with the surround at the lowermost possible ram travel position. Typically, the ram can possess a top bar projecting to either side at which it can contact in each case one strip of such elastomeric material.

The features described above (polymeric slip thrust washer, polymer spacer members and elastomeric buffer strips) are usually all used in combination to reduce noise transmission from the drive. Preferably, the drive comprises a larger grooved wheel integral with, or attached around the screw and a smaller grooved drive wheel connected thereto by a flexible belt to give good torque transmission. The belt is preferably notched with V-notches at intervals around its inner periphery Ito ensure ready passage around the groove in the smaller wheel in a small-radius curve).To piessrve the tensioning of the belt necessary vor this h ivo,3 ratio high- torque transmission (hitherto only ob-,ain- able by noise-creating drive chains) it is preferred, to provide one or more tensioning means. One such can be a frame mounting the smaller wheel movable and securableto adjust the spacing of wheel centres; additionally or alternatively one end of a biassed pivoted arm, usually provided with an idle roller, can be brought to bear inwardly on the outer periphery of a belt flight between the wheels.

The ratio between wheel diameters is usually from 4:1 to 8:1 e.g. about 6:1.

In another aspect the invention provides a domestic waste compactor of the type referred to with a ram member of box-like construction with a square or rectangular horizontal cross-section possessing a top bar, for securing the nut, which projects to each side of the ram, and vertical strengthening members extending down inside each side of the ram from beneath the top bar. In a valuable embodiment the ram has an integral cast structure.

In addition to the features discussed above as relating to the drive train, there are aspects of the invention, applied to domestic waste compactors of the type referred to, relating to the drawer and cabinet structure.

In one such aspect there is provided a drawer having at each upper inner corner a vertically journalled wheel of soft surface construction, the transverse distance between the laterally outer extremity of each wheel corresponding to the internal cabinet width, whereby accurate location of the drawer is facilitated. Usefully, this is combined with a guide member along part of the length of the drawer at each side towards the upper edge thereof, of the same overall transverse distance between external faces.

In another aspect, the drawer is provided with wheels at or near each lower corner, the inner wheels being castor wheels to facilitate steering of the removed drawer to a disposal area. In such an instance, the outer wheels can be adjustable in height since it is preferred for these wheels to rest on the floor and not within the cabinet housing.

A particular valuable feature is to provide the floor of the cabinet with at least two locating recesses or dimples for the forward position of the inner lower wheels. Thus, the drawer is accurately laterally positioned by the upper (or vertically journalled) guide wheels, to steer the castor wheels into the dimples and allow the base of the drawer to rest upon the floor of the cabinet. Preferably, two further, outer such dimples are also provided, to locate the castor wheels and define a half-way-out, filling, position for the drawer.

Another aspect is to provide at the outside of the drawer, e.g. in a surrounding inwardly projecting housing, a location for a deodorant block.

It is moreover preferred for the drawer to be provided with a removable internal bin of polymeric material, to receive a suitable polymer liner bag for containing the waste material. Such a bin can be flexible with side catches preventing accidential removal (e.g. when changing bags) but permitting intentional wall flexure and removal as necessary for occasional cleaning.

The construction of the cabinet itself also possesses features which are aspects of the present invention.

Thus, it is envisaged to provide a cabinet with a work-top cover, an uppermost control panel cover and an upper front panel hinged along its lower edge at the top of the drawer opening, in which removal of the control panel cover permits access for unsecuring and tilting forward of the front panel and for un-securing and sliding back the work-top.

The cabinet may further include switch members in a location operable by the drawer when this is pressed fully home, e.g. a generally vertical bar pivoted at the top to a microswitch and tiltable by a projection at the inner end of the trolley. If desired, a mechanically durable catch, holding the door shut when the ram has moved downwards, can also be provided.

The invention will be further described with reference to the accompanying drawings, in which Figure lisa generalised diagrammatic view of the equipment from the side, with a side panel removed, Figure2 is a general diagrammatic cross-section through the ram mounting and drive members thereof, Figure 2a is an enlarged perspective and sectional view of a variant of part of Figure 2, Figure 3 is a section also showing a variant of part of the features shown in Figure 2, Figure 4 is a top view of the ram within its mounting, Figure 5 is a perspective view of a ram guide member, Figure 6 is a perspective view of a ram constructed as a steel fabrication, Figure 7 is a perspective view of a ram constructed as a casting, Figure 8 is a top view of a drive mechanism showing two belt- tensioning means, Figure 9 is a side of view of the trolley, showing its relationship to the base of the cabinet when located therein, Figure 10 is a top view of the trolley within the cabinet, Figure 11 is a diagram showing alternative trolley positions, one position fully within the cabinet, and one position half within the cabinet, Figure 12 is a perspective view of a bin memberto be held within the drawer of the trolley, Figure 13 is a front view of the cabinet with the trolley removed, Figure 14 is a diagrammatic section showing a means of access to the controls, Figure 15 is a back view of the control cover panel, Figure 16 is a top view of the cabinet with the worktop removed, and Figure 17 shows a safety lock member.

Figure 1 shows the general layout of the equipment. A waste compactor generally comprises a trolley 1 housed in a cabinet 2 containing a ram mechanism and drive means 3.

Trolley 1 consists of a door portion 4 attached to a drawer portion 5, supported on wheels 6 and 7 and containing a bin 8. In use, it is located beneath a vertically movable ram 9, operated by screw 10 within nut 11 to move vertically within guides 12 on rotation of the screw. The screw 10 is rctated by an electric motor 13 operating over pulley 14 by means of belt 15 to a grooved wheel 16.

Figures 2 to 8 of the drawings show the drive train and moving ram parts 3, in more detail.

Figure 2 shows a vertical screw 10 keyed at its narrower upper end portion 17 to wheel 16, and protruding through slip thrust washer 18 to locate within collar 19 of top thrust plate. The bearing assembly so constituted is completed by a top member 21 secured to end portion 17. The threaded portion of the screw is movable within an injectionmolded nylon block 22 secured by screws 23 to the underside of top plate 24 of the ram member 25.

Ram member 25 possesses side plates 26, side strengthening struts 27 and bottom plates 28. It is vertically movable within surrounds 29, being spaced therefrom by spacers 30 located one at each corner. On top of surround 29 are located elastomeric buffer strips 31 in a position to be contacted by the projecting edges 32 of the top plate 24.

Around screw loins loosely fitted a stack of three disced spring (belvedere) washers 10a, in a configuration as shown for reasons described in more detail below.

Slip thrust washer 18 is a major feature of the present invention. We have found that a disc of polymer material such as nylon 66 can absorb the thrust of the ram, but still permit rotation of the hub of the wheel 16 in relation to the plate 20. Preferably, the uppermost surface of the wheel 16 is polished to assist easy rotation. Hitherto, rotary bearings have been provided as, for example, a ball race, and thrust has been separately accommodated by a flexible metal-to-metal thrust bearing, needing careful lubrication. However, we have unexpectedly found that the provision of a "floating", that is to say unsecured, washer member of such synthetic polymeric material gives the advantages of a low-noise transmission, ready movement, and good thrust characteristics in a permanent and reliable fashion.More than one such washer may be used, of the same of different material, at least one being of the polymeric material. The top member 21 can also be fabricated of such a synthetic polymer material. It need not resist pressure, since it merely acts as a support when the ram member 25 is withdrawn against its own weight.

Although disc 18 can be used without lubrication, lubricant can also be provided if desired. Figure 3 shows a detail of an alternative embodiment involving additional lubrication members. In this embodiment, the hub 33 of the wheel 16 is centrally recessed at 34. Slip thrust washer 18 lies within the recess, its top surface 1 8a being lower than the top surface 36 of the hub 33. An additional steel washer 37 is interposed between the slip thrust washer 18 and the underside of plate 20. In use, the recess is filled with lubricant. If desired, the slip washer 18 can possess through holes or grooves at its surface.

During a cycle of operation, the lubricant assists the free moment of the wheel 16 and hub 33 in relation to the plate 20. When the direction of movement is reversed to withdraw the ram member 25 there is enough "play" between the floor of recess 34, the surfaces of slip thrust washer 18, and the underside of steel washer 37 (especially if holes or grooves are provided) for lubricant e.g. heavy oil or grease to be drawn between the relatively movable surfaces.

Figure 2a shows an improved mounting of the rotary members in the top plate 20. Slip thrust washer 18 is replaced by two parallel washers 218a and 218b. Within the through hole in plate 20 is a collar 219 with an integral circumferential top flange 219a. The upper part 221 of the rotary components fits within collar 219 and is internally threaded at 222. The surrounding threaded wall is interrupted by diametrically opposite key slots such as shown at 223. Cap 224 flanged at 225 and possessing downwardly protruding dogs or keys at 226 fits from the top of the plate 20, being attached by threaded bolt 227 passing freelytherethrough to connect at 222 so that dogs 226 fit in slots 223. Cap 224 thus rotates with the rotary components, and all relatively rotary features are separated by washers 21 8a, 218b, collar 219 or flange 219a.This arrangement gives a secure support at all stages of the cycle and does not tend to become unscrewed at the end stage of operation.

Figure 4 shows the ram member itself in top view, reference numbers being generally as in Figure 2.

The edges 32 of the plate 24 overlie elastomeric buffers 31 to give a resilient stop at the lowest possible point of travel if this should be necessary, i.e. if the bin 8 described in more detail below is nearly empty.

Figure 5 shows the shape of nylon spacers 30, the function of which is to allow smooth quiet operation during movement of the ram member 25.

The ram member 25 itself can be variously formed. One variant is shown in Figure 6, and is a fabricated steel construction welded to a heavygauge base plate 38 with internal stiffening channels 29 welded in situ as shown beneath a welded steel top plate 40 shown for the purposes of clarity of illustration in dotted lines. Another variant, formed of cast alloy, is shown in Figure 7 where integral ribs 41 with threaded holes 42 at their upper ends are connected to the steel plate 43 to five a strong unitary construction.

Figure 8 shows the motor drive pulleys and drive belts. It includes two includes two belt-tightening mechanisms, either or both of which may be used. It comprises a motor 13, a small-diameter grooved pulley 14, a belt 15 and a large-diameter grooved pulley 16. Motor 13 is attached to the underside of plate 44. Small diameter pulley 14 protrudes above the plate 44 and is grooved to accommodate belt 15, which notched at 45 on its internal periphery. Large diameter pulley-wheel 16 is also similarly grooved.

One tensioning expedient is the provision of elongate fixing holes 46, carrying screws 47. This allows movement of plate 44 and thus allows the centre of pulley 4 to be moved away from the centre of pulley 16 to the extent necessary to tension the belt. Another preferred expedient is the provision of a tensioning arm 48, pivoted at 49, biassed by spring 50 so that the outer end of arm 51, carrying wheel 52, presses against the outer face 53 of the belt 15.

Prior art compacting devices utilise a chain drive, with consequent expense and noise. We have found that a belt drive is adequate. Because of the large ratio between the diameters of pulleys 16 and 14 (for example, 6:1 to get the necessary torque) and because of the relatively small spacing between the centres of the pulleys, notches on the inner periphery of the belt are needed to relieve stresses as the belt passes around the small- diameter arc of pulley 14.

It will be apparent that all the contacting moving parts of the drive system, that is to say belt 15, slip thrust washer 18, top washer 21, spacers 30, and the polymer nut 22, all involve a polymer/metal contact.

Thus, the drive train is quiet in operation, essentially lubrication free, and still of adequate power and reliability for domestic use.

Figures 9 to 12 of the drawings show the interrelationships between the trolley 1 and the cabinet 2.

The trolley door4 has a facing member 53 attached to the front panel 54 and spaced from the bottom edge to define a kick plate 55. At its upper edge is located an extrusion 56 to provide a pullhandle. Around the inner periphery of the door is a conventional rubber sealing strip 57 (shown partly broken away in the drawings). Each lowermost corner has an angled bracket 59, attached to the door by adjustment screws 60 in order to carry wheel 7.

To the inner face of the panel 54 of the door 4 is welded a drawer portion 5. This is also shown in Figure 10. This drawer portion consists of inclined side walls 61, and slightly inclined front walls 62 and rear walls 63 (these are not shown as such in Figure 9 for clarity of illustration). All these walls terminate in an upper rim 64 with an upwardly projecting stud 64a. Rearwall 63 is surrounded by a rearwardly projecting surround 65 carrying two castor wheels 6.

The whole structure is fabricated of folded and welded sheet steel. Stiffening profiles 66 and 67 extend along outside the side walls 61.

At each rearward corner of the drawer is located a vertically journalled soft rubber locating wheel 68, these wheels projecting to both the rear and the sides of the drawer as seen from above. To each side of the drawer are provided soft polymer locating strips 69 with rounded ends, providing accurate locating within the walls of cabinet 2. The drawer portion 5 also possesses side openings 70.

When fully loaded within cabinet 2 the drawer portion 5 stands with castor wheels 6 in recesses 71 of base 72 (see also Figure 11) Rear wheels 7 are located on the floor. At this stage stud 64a is received between two parallel guard plates 58, with diverging front guide portions 58a, to deflect operating rod 84 of microswitch 89.

Base 72 has an approach ramp 73, transverse stiffeners 74 at the underside (since it must resist the ram pressure), rear positioning rollers 75 and front levelling screws 76. These latter are made from elastomeric material to improve vibration-reduction and noise-reduction of the whole assembly. If desired, rollers 75 can also be replaced by levelling screws, for better adjustability on very uneven floors.

The drawer portion 5 carries a removable bin 8, and a replaceable deodorant or perfume block 77 located within the rearwardly projecting surround 65.

It will be apparent that the drawer portion 5 can be fully removed and pushed to a desired emptying location by steering the assembly using the castor movement of wheels 6. Moreover, on replacement, the wheels 6 fall into the recesses 71 so that the base 78 of the lower portion 5 lies on the base 72 of the cabinet. Figure 10 shows how the wheels 68 and strips 69 provide accurate laterla positioning.

Figure 11 shows diagrammatically the drawer portion 5 both fully in position (shown in dotted lines) and half withdrawn to a position for filling (shown in full lines). In the half-withdrawn position, wheels 6 are located in recesses 79. In the closed position wheels 7 are located inside pockets 80.

Figure 12 shows the bin 8. This is a resilient moulded sheet of polymer such as polyethylene with a molded catch 81 on each side face. It fits within drawer portion 5 with the catches 81 protruding through the holes 70. In use, a liner bag is placed in, and folded back over the top of, the bin 8. When this is full of compressed material, it can be pulled upwards. At this stage bin 8 is retained by the catches 81. However, if it should be desired to remove the bin 8, i.e. for replacement or cleaning, the resilient walls of the empty bin can be readily deformed inwards to release catch 81 from the holes 70.

The trolley/cabinet arrangement shown has the advantages of adjustment capabilities to different floors and to existing adjacent equipment. Thus, on installation, the trolley is pushed into cabinet 2 and the brackets 59 are lowered until the rear wheels 7 contact the floor, before tightening adjustment of screws 60.

In general the trolley provides self-alignment, manoeuvrability, easy access for filling, height adjustment of the plinth (i.e. kick strip), door - sealing, strong construction, and permanent location of deodorant block. Moreover, the front panel 53 can be tailored in length or colour and (by virtue of the adjustment brackets) in height to fit existing kitchen decor.

Figures 13 to 16 show features of cabinet construction.

Figure 13 is a view of the cabinet 2 from the front with the trolley removed. It possesses side panels 81, end panel 82, base 72 with entry ramp 73 and indents 71 and 79, and side pockets 80. At its upper end it possesses front cabinet panel 83, control cover panel 85 held by fixing screws at locations 86 (see Figure 15) and, over the top, worktop surface 87.

Figure 14 is a diagram of the upper front part of the cabinet with control cover panel 85 removed. It shows the location of a worktop fixing screw 88 beneath the front edge of worktop 87, and shows moreover front cabinet panel unsecured at its top edge and tilted forward about its lower edge for front access to the ram drive mechanism when necessary.

Figure 15 shows the control cover panel 85 from the rear, showing the locations of shaped slots at 86 and small immobilising screws at 90. The same screws 90 are removable whereby panel 85 can be lifted and pulled off, enabling access to the controls and if desired the fixing screws of panel 83 for further access. Also, this enables screws 88 to be removed.

Figure 16 shows the top of the cabinet with the worktop removed. Removal of screws 88 allows the top to be slid back to free rear studs from retaining slots 91 and exposing plate 92 covering the motor, or plate 20 covering the screw and ram.

The interaction of stud 64a and arm 85 upon microswitch 89 can provide a safe by override for the equipment, by actuating an electrical safety circuit whereby the machine cannot be operated unless the trolley is pushed fully home and after which any attempts to remove the trolley during operation of the machine will automatically switch the machine off. Once the machine has stopped after such action cannot be operated again until the trolley is pushed back fully home into the machine at which time the ram will automatically return to the rest position.

The compact cycle can then only be recommenced by pressing the "start" switch.

It may however also be desirable to provide an additional positive mechanical safety catch.

Figure 17 shows diagramatically such a catch.

Some portion of the ram mechanism, shown diagra matically at 93, on initial downward movement permits rocker arm 94, pivoted at 95, to support 96, to be moved downwards by tensioning spring 97.

The upward- moving side at 98 defines a hook which locks into a suitable ring 99 on the inside of door panel 54.

A cycle of operation typically involves the following sequence to drive and reverse the ram.

Downward motion of the ram commences when a "start" switch on the control panel is pressed. This energises, a "run" relay which in turn supplies power to a single-phase capacitor-start inductionrun motor having two windings i.e. "start" and "run". When the correct motor speed is reached a built-in centrifugal switch disengages the "start" winding and engages the "run" winding. The "start" switch is momentarily operated, but this is sufficient to provide a time in which the ram has travelled downwards to release a microswitch which bypasses the "start" switch and thus allows downward movement to continue after the "start" switch has been released. Immediately thereafter following a second microswitch is released (by further small downward movement) which causes a change-over relay to reverse the polarity of the motor start winding.As this winding has however previously been disengaged by the centrifugal switch, downward movement continues until maximum compaction is reached. At this point the motor stalls. The centrifugal switch closes, through lack of momentum. This re-energises the "start" winding, which is as described above in reverse polarity, causing the ram to rise upwards. Upward motion continues until the second microswitch is again activated and changes over the "start" winding polarity in readiness for the next compaction cycle. Immediately thereafter the microswitch is depressed, deenergising the run relay and stopping further motion. The spring washers 102 are a safety feature. If there is an inadvertent operation of the "start" button near the end of the cycle, the ram could jam at the top and damage the moving parts. The use of the spring washers 102 absorbs this movement resiliently, causing the motor to stall and then pushes the ram down again.

Claims (31)

1. A domestic waste compactor of the type referred to in which to resist the vertical thrust of the screw and to permit rotation thereof at least one slip thrust washer is interposed between means rotary with the screw and the underside of an upper thrust plate or of a member fixed in relation thereto.

2. A domestic waste compactor as claimed in claim 1 in which the slip thrust washer is a disc of a polyamide-based polymer.

3. A domestic waste compactor as claimed in claim 1 in which the slip thrust washer comprises a stack of two or more discs, at least one of which is a polyamide base polymer.

4. A domestic waste compactor as claimed in claim 2 or 3 in which the polymer disc further contains molydenum disulphide.

5. A domestic waste compactor as claimed in any one preceding claim in which the or each washer disc is contained within a large-diameter recess in the hub of a wheel integral with or attached to the screw and located beneath the thrust plate.

6. A domestic waste compactor as claimed in claim 5 in which the or each washer disc is grooved or perforated.

7. A domestic waste compactor of the type referred to, in which drive is effected by means of an internally threaded nylon nut attached to the ram.

8. A domestic waste compactor as claimed in claim 7 in which the nut is cylindrical and from 5 to 12 centimetres outside diameter with an axial threaded bore of 2 to 5 centimetres diameter.

9. A domestic waste compactor as claimed in claim 7 or claim 8 in which the ram is of square or rectangular horizontal cross-section and moveable vertically at a clearance within a surround defining a similarly square or rectangular opening, and in which the ram is isolated from direct contact with the surround by corner spacer members in the opening.

10. A domestic waste compactor as claimed in claim 9 in which the corner spacer members are formed of low-friction synthetic polymeric material.

11. A domestic waste compactor as claimed in claim 10 in which each lower spacer member is an integral moulding of polyamide having parallel end faces, for accommodation at top and bottom faces of the surround separated by a shank L-shaped in horizontal cross-section.

12. A domestic waste compactor as claimed in any of claims 9 to 11 in which the surround supports at its top face elastomeric buffer material to prevent projecting ram portions from contacting the surround.

13. A domestic waste compactor of the type referred to in which the drive train comprises a larger grooved driven wheel integral with or attached around the screw, and a smaller grooved e drive wheel connected thereto by a flexible belt.

14. A domestic waste compactor as claimed in claim 13 in which the belt is notched with intervals around its inner periphery to ensure ready passage around the smaller wheel.

15. A domestic waste compactor as claimed in claim 13 or 14 in which tensioning means are provided for the belt.

16. A domestic waste compactor as claimed in claim 15 in which the tensioning means is a biassed pivoted arm provided with an idle rollerjournalled thereon, which can be brought to bear upon the outer periphery of a belt flight.

17. A domestic waste compactor as claimed in any of claims 13 to 16 in which the ratio between wheel diameters is from 4 to 1 to 8 to 1.

18. A domesticwastecompactorofthetype referred to in which the ram member is of box-like construction with a square or rectangular horizontal cross-section, possessing a top bar for securing the nut, projecting to each side of the ram, and vertical strengthening member extending downward inside each side of the ram from beneath the top bar.

19. A do mestic waste compactor as claimed in claim 18 which the ram has an integral cast structure.

20. A domestic waste compactor of the type referred to comprising a drawer having at each upper corner a vertically journalled wheel of soft surface construction, the transverse distance between the laterally outer extremity of each wheel corresponding to the internal cabinet width to facilitate accurate location of the drawer.

21. A domestic waste compactor as claimed in claim 20 in which each drawer comprises two guide members, one extending along the length of each side face of the drawer, towards the upper edge thereof, the overall transverse distance between external faces of the guide members being equal to that between the laterally outer extremities of each vertically journalled wheel.

22. A domestic waste compactor as claimed in claim 20 or 21 in which the drawer is provided with support wheels at or near each lower corner, the inner wheels being castor wheels.

23. A domestic waste compactor as claimed in claim 22 in which the outer drawer wheels are adjustable in height.

24. A domestic waste compactor as claimed in any of claims 20 to 23 in which there are at least two locating recesses or dimples in the base of the cabinet to define the forward position of the inner lower wheels.

25. A domestic waste compactor as claimed in claim 24 in which the base of the cabinet has two further locating recesses or dimples to define a half-way out or filling position for the drawer.

26. A domestic waste compactor as claimed in any of claims 20 to 25 having a location for a deodorant block formed therein or attached thereto.

27. A domestic waste compactor as claimed in any of claims 20 to 26 further comprising a removeable internal bin of polymeric material adapted to receive a suitable polymer liner.

28. A domestic waste compactor as claimed in claim 27 in which the removable bin has inwardly deformable sides provided with external side catches.

29. A domestic waste compactor of the type referred to, housed in a cabinet with a worktop cover, a removable uppermost control panel cover, and an upper panel hinged along its lower edge at the top of the drawer opening, wherein removable uppermost control panel cover, and an upper panel hinged along its lower edge at the top of the drawer opening, wherein removal of the control panel cover permits access for unsecuring and tilting forward the front panel and for unsecuring and sliding back the worktop.

30. A domestic waste compactor as claimed in claim 29 further comprising a switch member in a location operable by the drawer when this is pressed fully home, the switch member comprising a generally vertical bar pivoted at or near the upper end to a microswitch and tiltable by a projection located at the inner end of the trolley.

31. A domestic waste compactor as claimed in claim 29 or 30 further comprising a mechanically durable catch to hold the door shut when the ram has moved downwards.