GB2528968A - Cycloidal vibration motor module construction and frame arrangement - Google Patents

Abstract

A cycloidal vibration module comprises a motor 16 with a body 18 and end caps 20, 22 with a fan 24a, 24b and an eccentric weight 26 mounted at each end of a shaft 25 outside the end caps 20, 22, a pair of clamshell housings 12, 14 and a plurality of elastomeric rings 34 around the motor clamped between the motor 16 and housings 12, 14. The housings 12, 14 define a plurality of lugs 98 comprising slots 101 suitable for receipt of a frame. The motor module can be used in vibration therapy and the prevention and treatment of ulcers. The lugs 98 may be defined by two lug halves, one on each housing half. There may be four lugs 98. The rings 34 are disposed between the end caps 20, 22 and the housing 12, 14. The end caps 20, 22 and rings 34 may comprise first and second circumferential ridges and grooves 32, 36, 38, 40. The caps 20, 22 and housings 12, 14 may have windows (90 fig 6) to permit air flow. The body 18 of the motor may be cup shaped with one open end. The motor module may be incorporated into a chair, bed and/or mattress.

Description

Cycloidal Vibration Motor Module Construction and Frame Arrangement [0001] This invention relates to a cycloidal vibration motor module construction, and frame arrangement thereof. The motor has application in a support structure for a patient at risk of pressure ulcers, for example a pressure relief mattress or a cushion that incorporates the cycloidal vibration motor module. The motor also has application in vibratory therapy apparatus, such as vibration pads, either for medical use (for example in the treatment of leg ulcers, lymphoedema and DVT) or for personal use.

BACKGROUND

[0002] Pressure ulcers, also known as decubitus ulcers or bed sores, are caused by continuous pressure at a specific part of the body of an immobile patient.

[0003] Around 412,000 people in the UK are likely to develop a pressure ulcer every year ([1] Bennett et al, 2004), including 4-10% of patients admitted to hospital ([2] RCN, 2005).

An estimated 31% of pressure ulcers are severe, category Ill or IV, ulcers ([3] Posnett et al, 2009). Development of a pressure ulcer carries a 2-4 times increased risk of mortality for elderly patients in intensive care ([2] RCN, 2005).

[0004] In addition to the significant effects on patient morbidity and mortality, pressure ulcers also cause significant economic costs. Overall in the UK up to £4billion, which is equivalent to 4% of the NHS budget, is spent treating pressure ulcers and their related conditions annually, with costs for the most severe cases ranging from £11,000 to £40,000, depending on the complications.

[0005] Daily costs for a patient with a pressure ulcer are estimated to be between £38 an £196, with nursing and health-care assistant time accounting for almost 90% of this. The costs are correspondingly higher for more severe pressure ulcers, which often affect individuals with pre-existing health problems who usually have more complex requirements. Although the figures above are for the UK, similar problems exist throughout the world.

[0006] WO/2002/065973 discloses an ulcer, lymphoedema and DVT treatment device, comprises a motor adapted to deliver mechanical vibrations at its surface in three orthogonal directions at a frequency in each orthogonal direction of between 15 and 75 Hz and with an amplitude in each orthogonal direction of between 0.1 and 0.5 mm. A pad is connected to the drive unit. The motor drives an eccentrically mounted weight to provide oscillations of the casing in a radial plane. The device is employed to treat a patient suffering from leg ulcers, lymphoedema and DVT by applying three-dimensional vibrations.

A cover is provided to protect the pad from contamination.

[0007] It is known that vibration can assist in preventing the development of pressure sores. US-5606754-A suggests a bed which has vibration means to reduce the incidence of bed sores.

[0008] Studies have shown that the non-invasive application of sinusoidal vibration therapy to skin tissue can increase blood flow. The transmission of these vibrations into the tissues generates a range of mechanical forces and stresses on vascular endothelial cells, resulting in a vasodilatory response by enzyme nitric oxide synthase (eNOS), which stimulates production of nitric oxide (NO). Increases in blood flow have been demonstrated in in vivo circulatory models studying the effect of vibration.

[0009] Vascular produced NO by enzyme nitric oxide synthase is an important vasodilator to regulate vascular smooth muscle tone and retain healthy blood flow. NO also has a role in the endocrine and paracrine systems, including inhibition of platelet adhesion and aggregation; suppression of inflammatory mediators; inhibition of smooth muscle proliferation and migration; and promotion of endothelial survival and repair.

[0010] The present invention seeks to provide a construction of a motor module that is compact and versatile.

BRIEF SUMMARY OF THE DISCLOSURE

[0011] In accordance with the present inventions there is provided a cycloidal vibration motor module comprising: a motor, having a substantially cylindrical body terminated at each end by an end cap, the end caps each mounting a bearing supporting an armature of the motor on an armature shaft extending through the end caps and having a fan and an eccentric weight mounted at each end of the shaft outside said end caps a pair of clamshell housings mated together; a plurality elastomeric rings around the motor clamped between the motor and clamshell housings; wherein the clamshell housings define a plurality of lugs comprising slots suitable for receipt of an apertured sheet metal connector of a frame and having cross bores through which a fastener is receivable to clamp said metal connector.

[0012] The construction provides an efficient transfer of the imbalance caused by the eccentric weights into the end caps of the motor and thence into the clamshell housings through the elastomeric rings and into a frame connected to the lugs. There is a minimum of energy loss, and yet little opportunity for undesirable noise.

[0013] The lugs may be defined by two lug-halves, one lug-halve being disposed on each clamshell housing and defining the lug when the clamshell housings are mated together. Each lug halve may comprise a plate including said cross bore and fillets between each side edge of said plate and the body of the clamshell. Said plate may be stepped, whereby said slot is formed when the clamshell housings are mated. Optionally, there are four lugs.

[0014] Optionally, the module further comprises a frame attached to at least two of said lugs, where the frame comprises apertured sheet metal connectors, each connector having a bore, and a flexible plastics or metallic sheet to which said connectors are attached. Said connectors may be part of an integral connector unit.

[0015] Said connector may be connected to each of said two axially outwardly directed lugs extending from the substantially circular ends of the cylindrical housing and to one of the radially outwardly directed lugs from the cylindrical surface of the cylindrical housing.

[0016] The integral connector unit is [-shaped in one embodiment, whereby the motor module is substantially outside the plane of the sheet attached to the connector unit [0017] Thus the invention provides a modular cycloidal vibration sinusoidal motor module, controls therefor and a flexible sheet frame system that can be bonded into a foam and or material sandwich layer and integrated into either upholstered or moulded surfaces. This system can be attached to a standard production furniture framework e.g. bed, chair and couch. In doing so this converts a standard furniture frame into a product capable of transmitting cycloidal, sinusoidal vibration across its contact surface area, this transforms the frame and or product into a cycloidal vibration therapy product.

[0018] Cycloidal vibration therapy within the frequency range specified has been shown to stimulate circulation, reduce muscle tension and reduce pain via counter stimulation.

These resulting effects have been shown to treat and or relieve the symptoms of a range of clinical conditions.

[0019] The product may be incorporated inside a seat cushion, back rest and/or a foot stool, or other forms of seating. It may be incorporated inside a bed base or a mattress or a couch.

[0020] The clamshell housings when mated may define a substantially cylindrical housing. In the case of four lugs, two of the four lugs may be radially outwardly directed from the cylindrical surface of the cylindrical housing and other two lugs may be axially outwardly directed from substantially circular ends of the cylindrical housing.

[0021] Said elastomeric rings may be disposed between said end caps and the clamshell housings. Optionally, one of said end caps and said rings comprise a first circumferential ridge and the other comprises a first circumferential groove to receive the first circumferential groove and retain the ring axially with respect to said body. Likewise optionally, one of said clamshell housings and said rings comprises a second circumferential ridge and the other comprises a second circumferential groove to receive the second circumferential ridge and retain the ring axially with respect to said clamshell housings. In that way, the rings are securely located between the clamshells and motor and likewise positions the motor securely within the clamshells so that it is spaced therefrom but able to transmit the vibrations smoothly without rattling.

[0022] Said end caps and said clamshell housings may comprise windows to permit flow of air generated by rotation of the fans. The windows in the clamshell housings are optionally disposed in the substantially circular ends of the cylindrical housing.

[0023] The cylindrical body of the motor may be cup-shaped, having a base at one end and an open end at the other, wherein a central boss is formed on the base through which the armature shaft extends and on which a base end cap of the end caps is seated to locate the end cap, and hence the bearing, being a base-end bearing, and armature shaft, radially with respect to motor body.

[0024] A brush end cap of the end caps may be received in the open end of the body and comprise a plurality of collar bosses received in the open end and locating end cap, and hence the bearing, being an open-end bearing, and armature shaft, radially with respect to motor body. There may be two collar bosses, each receiving a brush bearing against a commutator on the armature shaft.

[0025] The brush end cap may have a body side and an outside, wherein each brush comprises an element having a terminal end and an orthogonal leg, and wherein a spring arm mounting a brush body is secured to the element intermediate its terminal end and orthogonal leg, the terminal end being received in a slot through the brush end cap and being electrically connected to a circuit board on the outside of the brush end cap. The terminal end may be apertured and receive a plug fitted in the end of the collar boss and retaining the brush in position.

[0026] Optionally, a U-shaped earth wire has a terminal limb and a contact limb, the terminal limb passing through a hole in the brush end cap and being electrically connected to said circuit board on the outside of the brush end cap, the contact limb being received in an edge slot of the brush end cap and bearing against the motor body to electrically connect the motor body with the circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 is a perspective exploded view of a motor module according to an embodiment of the present invention; Figures 2a and 2b are respectively a plan view and an end view of an assembled motor module as shown in Figure 1; Figure 3 is a perspective exploded view of the motor of Figure 1; Figure 4 is a side view of the motor; Figure 5 is a section on the line A-A in Figure 2b; Figures 6 (a) to (d) are respectively a perspective view (exploded) perspective view (assembled), end view and side view of a brush end cap of the motor of Figure 3 Figure 7a to 7c are respectively a side section and an end view (in the direction of the Arrow B in Figure 7a) of the brush end cap body of the end cap of Figure 6, and a partly exploded perspective view of the brush assembly of the end cap of Figure 6; and Figures 8a and b show respectively a section and a side view in the direction of the Arrow B in Figure Ba of a module including a frame in one connection arrangement.

DETAILED DESCRIPTION

[0028] Figures 1, 2 and 5 show a motor module 10 that comprises top and bottom shell housings 1214 and motor 16. Motor 16 has a substantially cup-shaped metal body 18 to which end caps 20,22 are fixed, one a cup base end cap 20, and the other a brush end cap 22. The end caps support an armature shaft 25 on the ends of which, outside the motor body 18 and end caps 20,22, are mounted fans 24a,b. The fans include a weight 26, integrally formed with blades 28 of the fans, so that the centre of mass of the fans is eccentric with respect to the rotation axis defined by the armature shaft 25. The fans are retained on the shaft 25 by grub screws 30 through the weights, the screws impinging on flats 27 provided on the ends of the shaft 25 which ensure alignment of the weights. The weights may be varied, as also can their effective distances eccentricity with respect to the rotation axis, whereby the degree and strength of vibrations created by the motor can be adjusted as desired. For example, where it is necessary to transmit the vibrations through a relatively great distance or through soft, resilient and/or vibration-damping material, it will be preferred to use heavier weights (eg in the region of 60g) whereas weights in the region of 20g may be used where less vibration is required. Of course, the less vibration that is required, the longer lasting will be the overall construction.

[0029] Around each end cap 20,22 is disposed a circumferential ridge 32 on which is retained a rubber/elastomer ring 34, provided with both a corresponding groove 36 to sit on the ridge 32 and a corresponding circumferential ridge 38 adapted to seat in corresponding grooves 40 formed inside the shell housings 12,14. When the housings are closed and clamped together around the motor 16 using eight set screws 42, the rings 34 are compressed, firmly securing and locating the motor inside the housing.

[0030] When the armature shaft 25 of the motor 16 rotates, the weights 26, being eccentric, cause the motor to vibrate, with a frequency equal to the speed of rotation of the shaft (between about 15 and 75 Hz). These vibrations need to be transmitted effectively to the housing 12,14, but not so as to create noise through direct intermittent contact of the end caps 20,22 and/or body 18 with the housings 12,14. The rings 34 provide this assurance by separating the motor from the housings, but nevertheless inter-connecting them through a resilient mounting that serves to transmit the vibrations of the motor to the housing both without noise and without significant damping of the vibrations.

[0031] Turning to Figures 3, 4 and 5, motor body 18 is a cup-shaped can, open at one end 18, but closed at the other end 18b except for a central boss 44 that is located in a corresponding recess 46 in the base end cap 20. The end cap is secured to the can body base 18b by screws 48. The motor is assembled by first securing the base end cap 20 to the can body 18 around the boss 44. Then, a first bearing 54 is pressed into a seat 56 of the base end cap 20. End caps 20,22 are hard plastics material injection moulded components, for example, from nylon or the like. Fans 24a,b each have a spigot 27, which is then pressed into an inner race of the bearing 54.

[0032] A second fan 24a and bearing 54 is then assembled and pressed into similar recess 56' of the brush end cap assembly 22. The motor comprises an armature 50, mounted on the shaft 25. The armature has a commutator 52 and engagement of the armature with the brush end cap 22 involves positioning of motor brushes 70 (described further below) with the commutator 52. The armature shaft 25 is a close sliding fit in the spigot 27 of the fan 24a. It plastics sleeve 29 that abuts the spigot 27, limiting insertion of the shaft 25 in the spigot. The motor armature is then secured axially with respect to the brush end cap 22 by the grub screw 30 in the fan 24a.

[0033] That assembly is then inserted into the open end 18a of the cup body 18, collar bosses 58 being a close sliding fit in the opening, locating the brush end cap 20, and hence the armature centrally with respect to the body 18. At the same time, the other end of the shaft 25 is passed through the boss 44 of the body end 18b and recess 46 of brush end cap 20 and inserted in a close sliding fit through the spigot 27 of the fan 24b, and again secured thereto by grub screw 30 in the fan 24b.

[0034] Permanent magnets are located in the can body 18 and interact with the armature in the usual way of a permanent magnet motor. However, the invention is not predicated on the type of motor employed.

[0035] Turning to Figures 6(a) to (d) and 7a, b and c, brush end cap 22 is itself an assembly comprising the end cap body 22, brushes 70, and suppression and electrical connection board 80.

[0036] As described above, brush end cap 22 comprises central recess 56' to receive bearing 54 that supports the spigot 27 of fan 24a. Externally of the recess 56' are the collar bosses 58, further bosses 58a, and circumferential ridge 32. Windows 90 are disposed between to allow cooling airflow through the motor generated by the fans 24a,b.

(Similar windows are in the base end cap 20, but are not shown or described further.) [0037] Through the collar bosses 58a is formed a slot 72, adapted to receive the terminal 74 of brush 70. Brush 70 is a brass element 75 having a leaf spring arm 76 welded thereto (or otherwise connected for electrical communication therewith). An apertured leg 78 is substantially orthogonally arranged at the end of the element 75, remote from the terminal 74. The slot 72 is open at at least one side to allow egress of the arm 76 when the brush is inserted therethrough. After insertion, a plug 77 is pressed into a hole 79 in the boss 58, through the apertured leg 78, to retain the brush in position.

[0038] The terminals 74 protrude through the other side of the brush end cap 22, as shown in Figure 6(a). Also, a U-shaped earth wire 82 is provided, which has a terminal end 82a and a contact end 82b. The terminal end is inserted through a hole 84 in the end cap (see Figure 7b) whilst the contact end is received in a slot 86 in the edge of the brush end cap 22 so as to hold the earth wire in correct orientation with respect to the end cap and so that the contact end stands slightly proud of the cylindrical surface defined by the collar bosses 58. The end 82a of the earth wire also protrudes through the brush end cap 22 to its other side.

[0039] An arc shaped circuit board 80 is provided with control wires 88 soldered to tracks printed on the board. The board has slots 92 and a hole 94 corresponding with the positions of the terminals 74 and earth wire 82a where they protrude through the end cap and, after positioning the board on them as shown in Figure 6(b), they are soldered to the tracks 90 whereby the board, the earth wire and partially the brushes 70 are secured and complete the end cap assembly. The board also comprises circuit elements 96 that serve to dampen/filter electra-magnetic emissions of the motor 16, generated by interaction between the armature 50 as it rotates and the permanent magnets in the can body 18.

The wires 88 include an earth grounding wire so that the motor cup body 18 is grounded through filter 96, one of tracks 90 and earth wire 82 adapted to contact the can body 18 on assembly of the end cap in the open end 1 8a of the can body. The other two wires provide current that is supplied to the brushes 70. The voltage applied across said other two wires may be any convenient DC voltage (perhaps 12V or 24V) and may be variable to enable variation in the speed of operation of the motor 16.

[0040] Each spring arm 76 of the brushes 70 has a dampening rubber block 83 and a carbon/graphite brush element 85 for engagement with the commutator 52. When terminal 74 is inserted in and through slot 72 in the brush end cap 20, the spring arm 76 is constrained by the slot engaging the sides of the terminal 74 to lie close to the rotational axis 25a of the shaft 25 of the armature 50. When the armature 50 is fitted to the brush end cap 22, the brushes are prized apart to receive the commutator 52 and so that they press against the commutator to make good electrical contact therewith.

[0041] Thus, the order of assembly is as follows: brush end cap 22 is assembled and then fitted on the commutator 52 end of armature and retained in position by engaging the grub screw 30 with the fan 24a; next the base end cap 20 is assembled and screwed to the cup-base end 18b of the can body 18; finally the armature 50 with brush end cap 22 is inserted into cup body 18 with the shaft 25 passing through the fan spigot 27 of the fan 24b and being fixed thereto by its grub screw 30. At the same time, collar boss 58 locate radially the armature and end cap 22 with respect to the body 18, and tabs 18c can both rotationally align the brush end cap 22 with respect to the body, by engagement with a tab 22a on the bosses 58, and optionally be crimped to further secure the body to the brush end cap 22.

[0042] Once the motor 16 is assembled, elastomer rings 34 are attached around ridges 32 on the end caps 20,22 and the motor is inserted in one shell of the shell housings 12,14. The other is clamped around the motor using the screws 42.

[0043] The shell housings 12,14 comprise windows 96 at each end, whereby cooling air can be drawn in and expelled by the fans 24a,b. They also comprise four halves 12a-d, 14a,d of what form lugs 98 of the module 10. The lugs are plates reinforced by fillets 99 and a step in the plates define a slot 101 (see Figure 2b) when the clamshell housings are assembled and clamped together along their joint line. The slot 101 is adapted to receive sheet metal connectors (not shown) of a frame (not shown) to be vibrated by the module 10. Screws pass through holes 103 in the plates of lug-halves 12a-d and screw into threads 105 provided holes in the plates of lug-halves 14a-d, whereby the metal connectors of the frame may be clamped securely. The threads 105 may be provided by brass inserts or the like.

[0044] The module 10 is versatile in that any arrangement of frame can be provided and attached, for example a frame similar to that disclosed in WO/2002/065973 or one comprising a plastics sheet bonded to foam for integration in a mattress or chair cushion, as disclosed in our copending application filed contemporaneously herewith and having the title "Cycloidal Vibration Support Structure, Mattress and Cushion", which is specially adapted for alleviation of pressure sores.

[0045] Cycloidal vibration therapy is a form of sinusoidal vibration in the frequency range of 15 to 75 Hz with an amplitude varying between 0.1 and 2 mm, depending on the orthogonal direction in the X,Y or Z axis. An acceleration rate of between 2 and 40 mE2 RMS is provided, generating between 0.3 and 2G at the surface of the device or frame to which the motor is fixed.

(0046] The motor arrangement, housed in the two piece housing with multiple mounting points allows for mounting to a frame or framework in various configurations at a range of angles. The motor is mechanically clamped in position, and supported by the elastomeric rings. The offset weight is mechanically and/or adhesively secured to the shaft of the DC motor, either at one end or both. If two weights are employed, they are aligned so that they are symmetrical to each other. As shown, the offset weight is cast into the fan arrangement so that it generates the required sinusoidal vibration but also creates air flow to cool the motor. The offset weight on the fan can be varied in size dependant on the weight required, this weight can alter the displacement within the range 0.1 and 2mm at the surface of the device it is mounted within.

[0047] The cycloidal vibration sinusoidal motor 16 is controlled electronically (by means not shown connected to the wires 88) to set and alter: the speed of the motor; the running time of the motor; and a range of oscillation patterns, for example by setting the motor speed to increase and decrease over a set time period.

[0048] The module 10 is connected to a frame by means of a mechanical fix. This may be directly to a frame, or by means of a bracket connecting the module to the frame through any angle up to 90 degrees. Using a bracket allows the motor module to be angled and displaced an appropriate depth or position relative to the frame and its mounting within a product such as a bed or seat cushion.

[0049] The frame may comprise a plastics sheet or mesh bonded between two layers of soft, resilient polyurethane or other plastics foam, to generate a sandwich arrangement.

One layer may form a top layer and become the surface of the product that contacts the human and or animal body. The other layer is supported by the product (bed or seat) and isolates the vibrations from the environment. The softness of the two layers may be different.

[0050] Referring specifically to Figures 8a and b, of a vibrating support structure 100 comprises a flexible plastics or metallic sheet frame 112 bonded to a layer of foam 114.

Vibration module 10 is attached to sheet frame 12 via housing 12,14. Connection lug 12b,14b connects the housing 12,14 to flame 112 via [-shaped connectors 122 and bolts 124. However, the skilled person will understand that any means of connecting housing 12,14 to frame 112 that results in a sufficiently rigid attachment between the housing and the frame for vibrations to be transmitted from the housing to the frame would be suitable.

In some embodiments. Connections are not limited to [-shaped connectors 122 and straight connectors or connectors turned through other than right angles are also feasible.

[0051] In Figure Sb, the L-shaped connector 122 can be seen to have three connection legs or points 128 to the motor module 10 so that a particularly strong and rigid connection between the motor and frame 112 can be achieved.

[0052] A foam layer 114 may be bonded to sheet frame 112 using adhesive or any other suitable bonding technique. Although the embodiment shown in Figure 8a shows foam 114 only bonded to one side of sheet frame 12, in some embodiments a layer of foam 114 is bonded to both sides of sheet frame 12, whereby frame 112 is sandwiched between layers of foam 114. In the arrangement of Figure Ba, the arrangement is such that, then the support structure is itself supported on a frame such as a bed frame or the like, the motor module 10 effectively hangs from the frame 112. This may be because the thickness and stiffness of the foam layer 114 is sufficient to prevent the motor module 10 from contacting a surface on which the support structure is placed when a user is supported by the support structure 100, for example, on a mattress or cushion 130 on the support structure. A suitable depth of layer of foam 114 may be between 5 and 30cm, preferably between 10 and 25cm. Furthermore, foam 114 may comprise two or more layers of foam having different stiffnesses and/or thicknesses. Alternatively, the layer 114 may be much reduced and instead the structure on which the layer 114 is placed has an aperture or space to receive the depending motor module 10.

[0053] In the arrangement shown, the connector 122 is [-shaped and depends from under the sheet frame 112, which substantially forms a T-shape in section. However, the frame 112 need not extend in both directions and instead the motor module could be at one end. Indeed, the sheet 112 could be slipped under a cushion with the motor assembly outside the confines of a chair or bed structure and cushion or mattress supported by the respective chair or bed structure. Likewise the connector 122 need not be [-shaped.

The motor module 10 could be in alignment with the sheet 112, in which event tha mattress or cushion 130 received and the foam 114 beneath would need to be thick and firm to avoid the presence of the motor being felt by a person supported on the cushion or mattress 130, assuming they were above the motor 10. Again, of course, the motor could be positioned outside the contact area.

[0054] In an embodiment, the layer of foam 114 may be provided with V-shaped cutaways (not shown), which cutaways allow foam to be bent in the region of the cutaways. This allows a suitable bed to bend the mattress, for example to bring a patient lying upon it into a sifting position. The sheet frames 112 may be sufficiently flexible to be bent itself, or it may include hinges corresponding with the V-shaped cutaways. The frame 112 may comprise a sheet of plastics material of between 0.25mm and 2.5mm thickness.

A suitable plastics frame may comprise a solid plastics sheet, a plastics lattice or a plastics mesh. Alternatively, the sheet frame could be metal, for example, stainless steel between 0.25mm and 1 mm thick, welded or riveted into a lattice frame, and, again, having the option to bend at pivot points.

[0055] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0056] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments.

The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0057] The reader's aftention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

REFERENCES

[1] GERRY BENNETT, CAROL DEALEY, JOHN POSNETT; The cost of pressure ulcers in the UK, Age and Ageing 2004; 33: 230-235 [2] The management of pressure ulcers in primary and secondary care: a clinical practice S guideline. RCN clinical guideline. September2005 [3] Posnett J et al., The resource impact of wounds on health-care providers in Europe, a flexible way to prevent pressure ulcers, Wounds UK, Vol 5, No 4, 2009 [4] PRESSURE ULCER PREVENTION pressure, shear, friction and microclimate in context. A consensus document. Wounds International 2010.

Claims (24)

1. CLAIMS1. A cycloidal vibration motor module comprising: a motor, having a substantially cylindrical body terminated at each end by an end cap, the end caps each mounting a bearing supporting an armature of the motor on an armature shaft extending through the end caps and having a fan and an eccentric weight mounted at each end of the shaft outside said end caps a pair of clamshell housings mated together; a plurality elastomeric rings around the motor clamped between the motor and clamshell housings; wherein the clamshell housings define a plurality of lugs comprising slots suitable for receipt of an apertured sheet metal connector of a frame and having cross bores through which a fastener is receivable to clamp said metal connector.
2. 2. A motor module as claimed in claim 1, wherein the lugs are defined by two lug-halves, one lug-halve being disposed on each clamshell housing and defining the lug when the clamshell housings are mated together.
3. 3. A motor module as claimed in claim 2, wherein each lug-halve comprises a plate including said cross bore and fillets between each side edge of said plate and the body of the clamshell.
4. 4. A motor module as claimed in claim 3, wherein said plate is stepped, whereby said slot is formed when the clamshell housings are mated.
5. 5. A motor module as claimed in any preceding claim, wherein there are four lugs.
6. 6. A motor module as claimed in any preceding claim, wherein the clamshell housings when mated define a substantially cylindrical housing.
7. 7. A motor module as claimed in claim 5 and claim 6, wherein two of the four lugs are radially outwardly directed from the cylindrical surface of the cylindrical housing and other two lugs are axially outwardly directed from substantially circular ends of the cylindrical housing.
8. 8. A motor module as claimed in any preceding claim, wherein said elastomeric rings are disposed between said end caps and the clamshell housings.
9. 9. A motor module as claimed in claim 8, wherein one of said end caps and said rings comprises a first circumferential ridge and the other comprises a first circumferential groove to receive the first circumferential groove and retain the ring axially with respect to said body.
10. 10. A motor module as claimed in claim 801 claim 9, wherein one of said clamshell housings and said rings comprise a second circumferential ridge and the other comprises a second circumferential groove to receive the second circumferential ridge and retain the ring axially with respect to said clamshell housings.
11. 11. A motor module as claimed in any preceding claim, wherein said end caps and said clamshell housings comprise windows to permit flow of air generated by rotation of the fans.
12. 12. A motor module as claimed in claim 11, when dependent on claim 6, wherein the windows in the clamshell housings are disposed in substantially circular ends of the cylindrical housing.
13. 13. A motor module as claimed in any preceding claim, wherein the cylindrical body of the motor is cup-shaped having a base at one end and an open end at the other.
14. 14. A motor module as claimed in claim 13, wherein a central boss is formed on the base through which the armature shaft extends and on which a base end cap of the end caps has a central recess seated on the boss to locate the base end cap, and hence the bearing, being a base-end bearing, and the end of the armature shaft supported by the base-end bearing, radially with respect to motor body.
15. 15. A motor module as claimed in claim 13 or claim 14, wherein a brush end cap of the end caps is received in the open end of the body and comprises a plurality of collar bosses received in the open end and locating the brush end cap, and hence the bearing, being an open-end bearing, and the end of the armature shaft supported by the base-end bearing, radially with respect to motor body.
16. 16. A motor module as claimed in claim 15, wherein there are two collar bosses, each receiving a brush bearing against a commutator on the armature shaft.
17. 17. A motor module as claimed in claim 16, wherein the brush end cap has a body side and an outside, wherein each brush comprises an element having a terminal end and an orthogonal leg, and wherein a spring arm mounting a brush body is secured to the element intermediate its terminal end and orthogonal leg, the terminal end being received in a slot through the brush end cap and being electrically connected to a circuit board on the outside of the brush end cap.
18. 18. A motor module as claimed in claim 17, wherein the terminal end is apertured and receives a plug fitted in the end of the collar boss and retaining the brush in position.
19. 19. A motor module as claimed in claim 17 or claim 18, wherein a U-shaped earth wire has a terminal limb and a contact limb, the terminal limb passing through a hole in the brush end cap and being electrically connected to said circuit board on the outside of the brush end cap, the contact limb being received in an edge slot of the brush end cap and bearing against the motor body to electrically connect the motor body with the circuit board.
20. 20. A motor module as claimed in any preceding claim, further comprising a frame attached to at least two of said lugs, wherein the frame comprises apeitured sheet metal connectors, each connector having a bore, and a flexible plastics or metallic sheet to which said connectors are attached.
21. 21. A motor module as claimed in claim 20, wherein said connectors are part of an integral connector unit.
22. 22. A motor module as claimed in claim 21, when dependent on claim 7, wherein said connector is connected to each of said two axially outwardly directed lugs extending from the substantially circular ends of the cylindrical housing and to one of the radially outwardly directed lugs from the cylindrical surface of the cylindrical housing.
23. 23. A motor module as claimed in claim 21 or 22, wherein said integral connector unit is L-shaped, whereby the motor module is substantially outside the plane of the sheet attached to the connector unit.
24. 24. A cycloidal vibration motor module substantially as described herein with reference to the accompanying drawings.