Abstract:
An adjustable orientation device includes a rigid spherical bearing surface and a sleeve made of a hard, non-visco-elastic material. The sleeve defines an inner surface which is part-spherical and is configued to receive the spherical bearing surface having substantially the same radius of curvature as the part-spherical inner surface and also defines at least one gap. The device includes a means for adjusting the size of the gap in the sleeve, typically a screw clamp which may be associated with an outer sleeve. When the gap is relatively wide, the sleeve can move freely over the spherical being surface, however when the gap is narrowed frictional engagement between the sleeve and the bearing surface increases and clamps the sleeve and the bearing surface in a fixed orientation. The device can be used to mount various object particularly speakers and projectors.

Description:
FIELD OF THE INVENTION 
     This invention relates to an orientation device. In particular, the invention relates to improvements in adjustable, clampable, orientation devices for mounting equipment including, particularly but not exclusively, speakers, microphone stands, slide projectors and the like. 
     BACKGROUND OF THE INVENTION 
     Problems arise when using slide projectors, and similar equipment, to project images onto screens in large halls, such as university lecture theatres and the like. In large halls, the slide projectors are generally located a considerable distance from the screen, so that small adjustments to the alignment of the slide projector are magnified and translate into much larger movements of the projected image on the screen. To align the image properly, requires careful adjustment and aiming which is done by rotating, tilting and yawing the slide projector. Most projectors have adjustable legs for that purpose but they are crude and wobbly and cannot prevent misalignment when the projector gets bumped or nudged. 
     In order to solve the above problem, the inventors of the invention to be described hereinafter, looked at various existing devices which provide swivel links/orientation devices which they believed might be suitable for use in orienting and aligning slide projectors and the like. However, while many of the devices which provided swivelling with clamping/locking had good locking capabilities, they could not be finely adjusted while being partially clamped. In other devices with good adjusting properties the locking was insufficiently strong and reliable. Many of the existing devices were also over-complicated and in some cases correspondingly expensive due to their providing movement and clamping about three orthogonal axes. 
     A typical swivel mechanism utilises one axle per axis, requiring one locking mechanism per axis such as in a typical camera tripod, and while this system is functional, it requires adjustment of three different clamps for adjustment in three different axes. 
     Another prior art device is a theatre light mounting. That device comprises a spherical member coated with a deformable soft plastic. The member is fitted into a concave mating socket which has truncated spikes protruding inwards. When the device is clamped, the spikes are pressed into the plastic. This device holds its orientation well. However, the plastic retains the spike depressions for a long time and this makes the device unsuitable for quick re-alignment. Also, it is difficult to make slight adjustments with this device. 
     Similar problems exist with stands and mounts for mounting large speakers. 
     It is an object of the present invention to alleviate the problems of the existing orientation devices described above. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided an adjustable orientation device including: 
     a first part including a rigid part-spherical bearing surface; 
     a second part including a sleeve made of a hard, non-visco-elastic material, the sleeve defining an inner surface which is part-spherical and is configured to receive the part-spherical bearing surface, having substantially the same radius of curvature as the part-spherical bearing surface, the sleeve defining at least one gap; and 
     adjustment means for adjusting the size of that gap, the arrangement being such that when the gap is relatively wide the sleeve can be moved freely over the spherical surface, the gap being arranged to be narrowed by the adjustment means characterised in that as the adjustment means is progressively tightened resistance to relative movement of the sleeve over the surface is also progressively increased allowing smooth controlled movement of the parts at different levels of friction providing clamping ranges from light locking to rigid locking when frictional engagement between the sleeve and the bearing surface retain the sleeve and surface in a fixed orientation and wherein the engaging surfaces of the bearing surface and sleeve are resistant to galling. 
     The preferred bearing surface is defined by a sphere with a large central bore extending from one pole of the sphere to the opposite pole to define a cylindrical bore suitable for receiving a shank. 
     A particularly simple method of manufacturing an orientation device embodying the present invention is by customising an existing spherical bushing. Spherical bushings are made be a number of manufacturers including IKO Nippon Thomson Co., Ltd of Japan. Typically such a bushing consists of two parts: a ball with a large hole through it for a shank, sitting in a sleeve which is machined to the contour of the ball. The sleeve has an axial split, to enable the ball to be inserted in the sleeve which is closed in use when the bushing is assembled. If material around the split is removed to widen the split to define a gap, the sleeve can be compressed until the ball cannot be moved any more. 
     Thus the present invention provides, an adjustable link, or orientation device, which, when fitted to a support, allows adjustment of the orientation of the equipment mounted to it. One element, say the spherical surface is connected directly or indirectly to the equipment, the other element being the sleeve is attached to the surface or object to which the equipment is to be mounted. This link has associated with it methods of clamping so that the equipment may be held at any orientation within the scope of operation of the support. Clamping may be of varying degrees to provide effects which range from light holding to rigid locking. In the case of equipment which is re-orientated often by hand, by careful adjustment, it is possible to provide just enough resistance to hold the equipment at a suitable orientation and also readily allow movement when subjected to any additional force. Thus, the orientation device can be adjusted under light resistance and then tightened and importantly, when tightening, the device will not slip. The relative orientation of the components stays the same. 
     In one aspect of the invention clamping is obtained hydraulically by means of cylindrical bore having a groove or channel extending around the inner circumference of the bore and a sleeve or the like covering the channel/groove such that application of pressure to a hydraulic medium in the groove causes the sleeve to bow inwards to clamp a cylindrical object, such as the sleeve or possibly an axle, in the bore. 
     Typical uses for the present invention include mounting speakers, in boom microphones, and slide projectors; mounting overhead, video and film projectors; mounting lights, video, still and film cameras; mounting optical, electro magnetic and acoustic transmitters and receivers; mounting viewing equipment such as magnifiers, binoculars, telescopes; mounting display equipment such as placard, card and label holders; signs, mirrors, and in tool holding and work holding equipment e.g. swivel vices. 
     When the device is to be used for mounting slide projectors and lenses there is a need to prevent unauthorised people from removing the projector or lens from the hall or the like where the projector is fitted. Thus in a preferred embodiment the invention provides a plate to which the projector can be secured, a lens retention device, such as a ring extending around the lens, the ring being secured to the plate, and an orientation device of the present invention, one element of which is secured to the plate and the other element being securable to a table bench, ceiling or other surface on or to which the projector is to be mounted 
     Normally the slide projectors are mounted in a room at the back of a lecture theatre where the projector projects through a window to the screen at the front of the theatre. The projection lamps sometimes need to be replaced during a slide show and are therefore in many projectors hold replacement lamps in a drawer like cartridge which pulls out from the back of the projector. When the projector is mounted against the back wall of a classroom or lecture theatre, access to this module requires turning the projector and this means that the projector has to be re-aligned afterwards. 
     Thus, in another aspect of the invention the clamping means includes means for allowing the projector and mounting assembly to turn in one direction away from a project position, a stop means which set at the project position and biasing means to bias the projector towards the stop means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a sectional view of a typical spherical bushing; 
     FIG. 2 shows a typical spherical bushing but with an added gap in the outer ring; 
     FIG. 3 shows the bushing of FIG. 2 fitted into first clamping mechanisms wit a stem added; 
     FIG. 4 shows sectional view of a second clamping mechanism using a screw and two opposite contact points; 
     FIG. 5 shows a further embodiment of a clamping mechanism; 
     FIG. 6 is a schematic drawing of a projector mount; 
     FIG. 7 is a schematic drawing of a projector mounted on the projector mount of FIG. 6; 
     FIG. 8 shows a further embodiment of a clamping mechanism; 
     FIG. 9 is a schematic drawing of a projector mounted on a second embodiment of a projector mount; 
     FIG. 10 shows a speaker on a mounting; and 
     FIG. 11 is an enlarged view of the mounting of FIG.  10 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, FIG. 1 shows a section through a typical spherical bushing  10  comprising an inner ring  12  whose outer surface  14  is spherical and an outer ring, or sleeve,  16 , whose inner surface  18  is also part-spherical and defines the surface of a spherical segment. In such a spherical bushing the inner ring is free to rotate about its central axis  12 A. The ring  12  is also free to turn inside the sleeve  16  so that its axis  12 A turns relative to the axis  16 A of the sleeve. Such bushings are well known in the art and are often used in heavy machinery such as cranes bulldozers and the like and are particularly used to mount ends of large hydraulic cylinders, with a shank being mounted in the inner ring. Such bushings are typically manufactured in a hard steel material such as high carbon chromium bearing steel, and the surfaces  14 ,  18  of the bushing are often coated to improve wear, smoothness, decrease friction etc. Typically, the bearing surfaces are phosphate-treated and coated with molybdenum disulphide. 
     The inner ring is inserted in the sleeve by means of a split in the sleeve which is opened in the assembly process to insert the inner ring and which is otherwise completely closed in the finished bushing. 
     FIG. 2 shows a first embodiment of the present invention, generally indicated at  20 , which includes an inner ring  12  identical to the ring shown in FIG.  1  and whose outer ring, or sleeve,  22  is similar to the sleeve shown in FIG. 1 but in which material on one side of the split present in the sleeve has been removed to define a gap  24 . If the outer ring  22  is now compressed to narrow the gap it will hold the inner ring  12 , firmly. 
     FIG. 3 shows the device  20  incorporated in a clamping means  26  for compressing the outer ring  22  of the device. The device includes a further ring, or outer clamping ring  28  which is disposed around sleeve  22  which defines a gap  30  which can be closed to compress the outer clamping ring  28 , and hence compress sleeve  22 , by means of a screw clamp mechanism, generally indicated at  32 . The outer clamping ring is fixed to or integral with a collar  34  which is in turn attached around a protrusion  36  at the top of a stem or pillar  38 . A further shank or rod  40  is mounted in the inner ring  12 . 
     It is to be noted that there is no gap between the sleeve  22  and the outer clamping ring  28  which acts directly on the sleeve  22  and compresses it radially. 
     Thus the present invention provides, an adjustable link, or orientation device, which, allows adjustment of the orientation of the rod  40  relative to stem  38 . Typically, in practical applications rod  40  or stem  38  will have equipment mounted to it or indirectly bear such equipment so that the adjustment allows the orientation of the equipment to be altered. The equipment may be held at any orientation within the scope of operation of the clamping means/support  32 . Clamping may be of varying degrees to provide effects which range from light holding to rigid locking. In the case of equipment which is re-orientated often by hand, the clamping device is able by careful adjustment of the screw clamp to provide just enough friction resistance between outer surface  14  and the inner surface  18  of the sleeve to hold the equipment at a suitable orientation and also readily allow movement when subjected an additional force. Once the correct orientation has been obtained, the device can be firmly clamped in place by tightening the screw clamp  32 . Importantly, when the additional tightening is carried out, the orientation of the components of the device will not change. 
     Although, the particular materials and coatings used are not essential to the present invention, the materials must have suitable properties. The materials must be hard. The sleeve material at least must be non-visco-elastic, ie it must not creep, or deform plastically under stress under the loads applied. Elastomers such as rubber, and soft easily deformable plastics are unsuitable. The materials should preferably have a high modulus of elasticity, at least 50000 psi, and preferably 100000 psi or more. Any deformation of the sleeve under the loads applied should be in the region where the material used behaves substantially elastically. 
     FIG. 4 shows a cross section through a similar device to that shown in FIG. 3 but in which an alternative clamping mechanism is utilised. In this embodiment the sleeve is held in a collar  50 , which extends around the outer surface of the sleeve but defines an arcuate space  52  which extends around the outside of the sleeve  22 , either side of the gap  24 . The two ends of the space  52  define contact points. A block  56  is attached to the opposite side of the collar to the gap and a threaded hole  58  extends through that block and the collar. A correspondingly threaded rod  54 , defining a handle  54 A is located in the hole  58 . In this embodiment clamping is achieved by turning the handle to cause the end  60  of the rod to impinge on the area  62  of the sleeve  22  opposite to the gap  24  to deform the sleeve and thus cause it to lock or clamp the inner ring, not illustrated in FIG.  4 . The contact points help to ensure that the clamping is provided on the sides of the inner ring at 120° to the end  60  of the rod. 
     FIG. 5 shows a further embodiment  70  which is very similar to that shown in FIG. 3 however as illustrated the outer clamping ring is not used and the screw clamp  72  is mounted in blocks  74  and  76  which are attached directly to the sleeve which acts as a structural element and transmits loads to the stem  38 . 
     FIG. 6 shows a schematic drawing of a device for mounting a slide projector utilising the principals of the present invention. 
     A pillar  38  is attached to a mounting plate  100 . Attached to this pillar is a collar  34  and sleeve  22  which encircles an inner ring  12  which is mounted on a shank or rod  40  in an assembly similar to that shown in FIG. 5. A cam operated tensioning device indicated at  102  acts on the clamping blocks  74  and  76  through a stalk  104 . A plate  106  is attached to shank  40 . Attached to this plate is a saddle  108  through which passes a rope or rod  110  which has an end  112  enlarged so that it cannot pass through the saddle. The other end of rope or rod  110  is attached to a lens lock indicated at  114  comprising a split ring similar to a hose clamp which encircles a lens  122 , shown in FIG. 7, to prevent unauthorised removal of the lens. A screw  116  or other more secure device clamps the two ends of the split ring together. 
     The stalk  104  is of a length that brings the tensioning device  102  to the side of the projector for ease of use. Where this fixture is used to attach other projectors, such as video/data projectors to the underside of a ceiling or pole, the stalk may be flexible and long enough to bring the tensioning device to below the projector for ease of access. 
     FIG. 7 shows a schematic drawing of a projector  120  mounted to plate  106  of the assembly shown in FIG. 6 with the lens  122  clamped in the lens lock  114  and the mounting plate  100  attached to a table, indicated at  124 . Orientation with the screen is achieved by rotating the projector sideways and tilting the projector using the built in screw adjustable feet  126  the orientation device is clamped after all adjustments are made. 
     Typical uses for the present invention include mounting overhead, video and film projectors; mounting speaker microphones, lights, video, still and film cameras; mounting optical, electro magnetic and acoustic transmitters and receivers; mounting viewing equipment such as magnifiers, binoculars, telescopes; mounting display equipment such as placard, card and label holders; signs, mirrors, and in tool holding and work holding equipment e.g. swivel vices. 
     Aside from what is described above, various mechanisms for contracting the outer ring or segments can be used to provide a smooth increase in friction to the point of locking. The swivel locks may be compressed using electromotive, hydraulic (liquid or gas) force or by screw, cam, joggle, or lever action. The clamping mechanism may take the form of a split collet with the spherical inner member held in a matching shape formed within the fingers of the collet. 
     Although in the above described embodiments the gap  24  in the sleeve  22  is made by removing material, the sleeve could be manufactured with a gap, or gaps. 
     Although in the above described embodiments the sleeve has a single gap, a sleeve having more than one gap could be used in appropriate housings. 
     As an alternative to a compressible sleeve, the sleeve can be cut into segments, and mounted a partly slotted housing with a conic outer wall. Compressing is done by pulling or pushing this into a corresponding cone, much like collets used in metal working. The sleeve could be replaced because the contour of the ball could be machined into such a collet. 
     FIG. 8 shows a sectional view through a further device  128  incorporating an alternative method of adjusting the size of the gap in the outer ring  22  of an orientation device of type already described and shown in FIG. 2, at  20 . The device  128  could also be used in many of the mechanisms described above. 
     The device  128  includes a generally annular housing  130 , which defines a central cylindrical bore generally indicated at  132 . The bore defines an annular groove  134  which extends circumferentially around the inner surface of the bore. The bore is sealed by a sleeve  136 , and an hydraulic medium in the bore can be pressurised which causes the sleeve  136  to bulge inwards which will compress the outer ring  22  which is disposed in the bore compressing, it which will narrow the gap  24  thereby causing the outer ring to clamp against the inner ring. 
     As can be seen from FIG. 8, there is an annular groove  138  which extends around the outside of the outer ring  22 . When pressure is applied to the hydraulic medium in the groove  134  the sleeve  136  is pressed against the external surface of the outer ring  22  and the sleeve  136  will distort and become pressed into the groove  138 . If the sleeve is made from material which will retain its shape after distortion, the shape of the annular groove  138  becomes reflected in the sleeve preventing the device  20  from being removed from the housing after the hydraulic pressure has been removed. 
     In the embodiment described above, the sleeve is bonded to the housing  130  to seal the bore  134 . 
     However in an alternative embodiment the sleeve could be made as part of the housing  130 . 
     There are other uses for this method of applying pressure. For example the housing  30  with sleeve  136  can be placed directly around a shaft and when pressure is applied movement in the shaft relative to the housing could be controlled, slowed or stopped. Various materials could be used in the sleeve or in coatings applied to it which could vary its properties. 
     The bore and sleeve may take the form of shapes other than cylindrical. For example the bore and shaft may be square, splined, or oval. When the matching housing with sleeve is used and hydraulic pressure is applied, the sleeve will bulge and press against the shaft. 
     This method may also be used on an external surface, where the sleeve form part of the outer surface of a shaft. Again the bore, shaft and sleeve do not need to be cylindrical. 
     Some uses for these devices are as dampers on swing arms of vehicles, bicycles and other suspension arms where the axle around which the swing arm rotates is held in a housing as described above and by applying hydraulic pressure to the housing where the sleeve includes or acts on a friction surface, the action of the swing arm is controlled. By varying the hydraulic pressure the swing arm damping could be modified to suit altering conditions. This device could replace or augment traditional shock absorbers. The method can be used to replace the mechanical components of a drum brake. 
     FIG. 9 shows a variation on the projector mount illustrated in FIGS. 6 and 7, which allows a slide projector to be rotated in order to access a replacement lamp housed in a lamp module of the projector. 
     Normally, slide projectors are mounted in a room at the back of a lecture theatre and the projector projects a beam light through a window to a screen at the front of the theatre. In some cases however, slide projectors are merely mounted against the back of the theatre. Occasionally, during a slide show, the projector lamp will blow and require replacement and many projectors thus include a drawer, which pulls out from the back of the projector and in which replacement lamps are usually placed in the event that a projection lamp will blow during a slide show. However, when the projector is mounted against the back wall of a lecture theatre or classroom, access to the lamp module requires one to turn the projector and this means that the projector has to be realigned afterwards. 
     Thus, FIG. 9 shows a variation of the projector mount shown in FIGS. 6 and 7 which allows the projector to rotate through sufficient of an arc to gain access to the lamp module and then allow the projector to return to the project position without the need for careful adjustment. As can be seen from the drawing, two arms  150  project from the collar  34  and the ends of those arms  150 A define a circular plate on which the adjustable feet  126  of the projector sit. A pin  152  is fitted to the pillar  38  and this is supported by a collar  156 . The collar defines a ramp or cam fit surface  154  on which the pin travels when the projector is turned about the axis of the pillar (in the direction of arrow A) to allow access to the rear of the projector and the lamp draw. Once the lamp has been accessed the projector can be allowed to automatically rotate back to the project position biased by gravity. The cam block  156  can be fitted to a table. 
     Although FIG. 9 shows an arrangement in which a ramp and pin cooperate with a stop to produce a device for lowering a projector to rotate axis to rear projector, the return being assisted by gravity, a spring or other resilient device could be used to force the projector back to the project position and a ramp is not essential. 
     FIGS. 10 and 11 show a speaker  200  fixed to a mounting, generally indicated  210  embodying the present invention. The mounting is fixed to one of a support rod  212 . The mounting  210  incorporates a orientation device embodying the present invention which can be used to adjust the orientation of the speaker in three dimensions. The other end of the rod may be fixed or may also incorporate an orientation device embodying the present invention. As can be seen, the split sleeve  28  is enclosed in an outer ring or outer sleeve  228 . The threaded clamp for tightening the sleeve  228  around the bore  12  is not shown for clarity. A rod  40  passes through the centre of the spherical bearing  12 . The ends of the rod are fixed to two metal plates  230 ,  232  which in turn are fixed to a further plate oriented perpendicular to the metal plates  230 ,  232  which can be fixed to a speaker by screws or the like for mounting the mounting device to a speaker. This device can be used to safely mount speakers weighing several hundred pounds and accurately align them. 
     It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.