TECHNICAL FIELD

This invention is directed to a support arm for attachment to an undersurface of a desk or other support structure, and, more particularly, to a support arm adapted for use with a computer keyboard tray to provide for adjustment of the keyboard tray between a plurality of work positions relative to the support structure.

BACKGROUND OF ART

Several different types of support arms are available for use in supporting computer keyboard trays in suspended relation at a plurality of selected work positions below a support structure, such as a desk or a work station. Most of such support arms are also adapted for movement of the keyboard tray to a separate stowed position displaced substantially beneath the desk or work station. Thus, prior art adjustable keyboard support arms provide for height-adjustment of the keyboard placed on the keyboard tray to an ergonomically correct, comfortable position, and also permit the keyboard trays to be located out of the way in a stowed position during periods of non-use.

One essential feature of keyboard tray support arms of the general type described is that the keyboard tray should be kept at a substantially constant orientation, either horizontal or close to horizontal, so that the

keyboard remains on the keyboard tray when in any work position, when in the stowed position, and also during travel between the available work positions and the stowed position.

Most prior art keyboard tray support arms embody a multiple linkage support arm, wherein two laterally opposed pairs of linking members are pivotally attached, one pair each, to the keyboard tray and to the support structure, typically by way of common fasteners such as rivets or the like, to form a four-sided parallelogram. The keyboard tray remains generally horizontally oriented at all times due to the geometry of the parallelogram-type support arm, and is typically spring biased in order to offset the weight of the arm itself and the keyboard tray. One parallelogram-type support arm exemplary of this type can be found in U.S. Patent No. 4,644,875 granted to Watt, which patent is incorporated herein by reference.

In prior art mechanisms, including that disclosed in the Watt patent, the support arm is typically mounted to the support structure by way of a mounting frame comprising a carriage member slidably supported by a track member for movement between a fully retracted stowed position, whereat the keyboard tray may be stowed beneath the support structure as previously referenced, and a fully extended position adjacent to the leading edge of the top surface of the desk or work station, at which position the keyboard is readily accessible by a user. In the fully extended position, the carriage member is held in position by a manually operated latching mechanism, and the support arm is thereafter

selectively movable to and lockable at one of a plurality user chosen work positions, under the control of a separate and distinct lock means. Thus, in order to stow the keyboard tray under the support structure, it is first necessary to manipulate the lock means so that the keyboard tray can be moved to a predetermined relatively lowered work position, whereat it will clear the undersurface of the support structure, and the latching mechanism must be separately and independently manipulated in order to allow the carriage member to thereafter slidably move from its fully extended position to its fully retracted stowed position beneath the support structure. The lock means and the latching mechanism must be separately and independently manipulated before forwardly moving the keyboard tray from the fully retracted stowed position to a selected one of its plurality of work positions. Such separate and independent manual manipulation of the lock means and the latching mechanism is time consuming, awkward, and inconvenient.

Another problem associated with parallelogram-type prior art support arms is that they tend to become slightly loose over time as the pins or rivets that pivotally attach together the linking members of the arms, become worn. Such looseness results in sloppiness in movement in the support arm and also in slight movement of the keyboard tray while in any of its work positions. Ideally, the keyboard tray should not move at all when locked in any of its work positions.

All parallelogram-type support arms have various disadvantages associated with them. They are relatively large and heavy devices, because of the number of linking members (typically four) that make up the support arm, and because they are typically constructed from sizable metal parts. Further, the working parts are all generally exposed, including the biasing spring member. Such exposure of moving parts may provide a safety hazard to the user, particularly to the hands and fingers of a user when reaching below the keyboard tray to adjust the work position thereof or stow the keyboard. Also, parallelogram-type support arms that are of reasonably high quality tend to be expensive.

It should also be understood that most adjustable keyboard trays can be used to support notebook type microcomputers, which microcomputers are typically only slightly larger than conventional computer keyboards. However, notebook microcomputers have a hinged flip-up display screen attached to the keyboard portion, which display screen extends upwardly and rearwardly from the keyboard portion when in a usable work position. Generally, it is desirable to position the keyboard tray such that the position of the keyboard portion of the notebook microcomputer is at a comfortable ergonomically correct height for the user, which would be approximately the same height aε for a conventional computer keyboard. In this case, the display screen of the notebook microcomputer may very likely extend upwardly to or beyond the top working surface of the desk or work station. However, with conventional keyboard tray support arms, the keyboard tray tends to move

significantly rearwardly under the support structure as the keyboard is lowered, thus causing the leading edge of the top working surface of the work station to contact the rear of the display screen of the notebook microcomputer, so as to hingedly close the display screen upon downward adjustment of the keyboard tray. Accordingly, an ergonomically correct keyboard position for using notebook microcomputers on keyboard trays may only be fully obtainable upon sacrificing the proper viewing angle for the screen display. This problem is exacerbated by the generally low light output levels of notebook microcomputer screen displays, which compounds the shortcoming of an already narrow range of readily discernable viewing angles.

Another disadvantage of prior art keyboard tray support arms is that they do not provide for security of notebook microcomputers when not in use, so as to preclude removal of same from the keyboard tray while in a stowed configuration.

It is an object of the present invention to provide a support arm for supporting a keyboard tray in a plurality of work positions, wherein the support arm is of a type other than a parallelogram-type support arm, which support arm keeps the keyboard tray in a relatively horizontal orientation at all times.

It is yet another object of the present invention to provide a support arm for supporting a keyboard tray in a plurality of work positions, wherein the keyboard tray can be moved from any of said plurality of work positions to its fully

retracted stowed position in a continuous motion upon manipulation of but a single lock means.

It is a further object of the present invention to provide a support arm for supporting a keyboard tray in a plurality of work positions, wherein the support arm is mechanically secure during operation and remains mechanically secure with extensive use over time.

It is yet a further object of the present invention to provide a support arm for supporting a keyboard tray in a plurality of work positions, wherein the support arm is relatively compact.

It is yet a further object of the present invention to provide a support arm for supporting a keyboard tray in a plurality of work positions, wherein the support arm is relatively lightweight.

It is yet another object of the present invention to provide a support arm for supporting a keyboard tray in a plurality of work positions, wherein the working parts are generally enclosed within a housing so as to not be exposed to the user.

It iε yet another object of the present invention to provide a support arm for supporting a keyboard tray in a plurality of work positions, wherein the support arm is relatively simple and inexpensive to manufacture.

It is yet a further object of a preferred embodiment of the present invention to provide a support arm for supporting a keyboard tray in a

plurality of work positions, wherein the support arm permits vertical height adjustment of the keyboard tray while permitting the attached display screen of a notebook microcomputer placed on the keyboard tray to be set substantially at any angular orientation desired by the user without substantial interference from the leading edge of the work station, desk, or other support structure to which the support arm is attached.

It is yet another object of the present invention to provide a support arm for supporting a keyboard tray in a plurality of work positions, wherein the keyboard tray may be securely locked in a fully retracted stowed position, by way of a key operated securing lock means, so as to preclude removal of, or tampering with the keyboard of, a notebook microcomputer placed thereon.

DISCLOSURE OF INVENTION

In accordance with the present invention there is disclosed a manually repositionable support arm mountable on a support structure for movement of a keyboard tray between a plurality of work positions. The manually repositionable support arm comprises a mounting frame adapted for mounting on the support εtructure, a first roller member having a first longitudinal axis, an outer circumferential surface, and one or more first circumferential bearing surfaces, the first roller member being rigidly mounted on the mounting frame, in fixed relation thereto and a second roller member having a second longitudinal axis substantially parallel to the first longitudinal axis, an outer circumferential

surface, and one or more second circumferential bearing surfaces. The second roller member is rigidly mounted on a depending portion of the keyboard tray in fixed relation thereto. A rigid houεing member substantially encases the first and second roller members in journalled relation about the first and second circumferential bearing surfaces so as to hold the first and second roller members in fixed spaced relation to one another and so as to permit relative rotation of the housing member with respect to the first and second roller members about the respective of the first and second longitudinal axes. A flexible link means is operatively mounted around both of the first and second roller members in fixed indexed engagement therewith εo aε to surroundingly link the first and second roller members for planetary movement of the second roller member about the first roller member within the rigid houεing member, such that the εecond roller member remains subεtantially rotationally aligned with reεpect to the firεt roller member during εuch planetary movement. There iε alεo provided a lock meanε operatively mounted between a εelected one of the first and second roller memberε and the rigid housing member to selectively preclude the relative rotation of the selected one of the first and second roller memberε with reεpect to the rigid housing member, thereby to selectively lock the keyboard tray attached to the second roller member in any one of the plurality of work positions.

Other advantageε , features and characteristics of the present invention, as well as methods of operation and functions of the

related elements of the structure, and the combination of partε and economies of manufacture, will become more apparent upon consideration of the following detailed description and the appended claims with reference to the accompanying drawings, the latter of which is briefly deεcribed hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 iε a εide elevational view of an embodiment of manually repositionable support arm according to the present invention, shown in solid lining in a relatively raised work position, and εhown in ghost outline in a predetermined relatively lowered work position, with portionε omitted for the εake of clarity;

Figure 2 iε an exploded perεpective view of the εupport arm of Figure 1;

Figure 3 is a perspective view of a portion of the εupport arm of Figure 1, showing the rigid housing member and various components therein;

Figure 4A is a substantially enlarged side elevational view of a portion of the second roller member of Figure 1, with the roll pin not diametrically expanded;

Figure 4B is a view similar to Figure 4A, with the roll pin diametrically expanded;

Figure 5 iε a εide elevational view of a portion of the rigid housing member and a portion of the slidable coupled track memberε and

latching mechanism, with details omitted for clarity;

Figure 6 is a diagrammatic side elevational view of the support arm of Figure 1 in use, with a keyboard tray in a relatively raised work position;

Figure 7 is a diagrammatic side elevational view of the support arm of Figure 1 in use, with the keyboard tray in a predetermined relatively lowered work position;

Figure 8 is a diagrammatic εide elevational view of the support arm of Figure 1 in use, with the keyboard tray in a fully retracted stowed position;

Figure 9 is an enlarged diagrammatic side elevational view of the εupport arm of Figure 6, εhowing the keyboard tray and a portion of the rigid houεing member;

Figure 10 iε a perspective view of the support arm of Figure 1, wherein the keyboard tray is in a relatively raised work position;

Figure 11 is a perspective view of the support arm of Figure 10, wherein the keyboard tray iε in a fully retracted εtowed position;

Figure 12 is a εide elevational view of a preferred embodiment of support arm according to the present invention, with the keyboard tray supporting a notebook microcomputer, in a relatively raised work position;

Figure 13 is a side elevational view of the embodiment of Figure 12, with the keyboard tray shown supporting a notebook microcomputer, in a relatively lowered work position, with a small portion shown cut-away for eaεe of illuεtration;

Figure 14 is a side elevational view of the embodiment of Figure 12 , with the keyboard tray shown supporting a notebook microcomputer in the fully retracted stowed poεition;

Figure 15 is a perspective view similar to Figure 12 , with the notebook microcomputer removed for greater clarity and additionally showing a locking system for the keyboard tray according to a further preferred aspect of the present invention;

Figure 16 is an enlarged perspective view of the embodiment of Figure 15, showing only a portion of a computer work εtation, with the keyboard tray shown locked according to said further aεpect of the present invention, in its fully retracted stowed position;

Figure 17 is an enlarged front elevational view of the embodiment of Figures 15 and 16, showing further detailε of said further preferred aεpect of the preεent invention;

Figure 18 iε an enlarged front elevational view similar to Figure 17;

Figure 19 is a greatly enlarged side elevational view of the embodiment of Figures 15 and 16, with certain parts shown in section for clarity of illustration.

BEST MODES FOR CARRYING OUT THE INVENTION

Referring now to Figures 1-11 of the drawings, a manually repositionable support arm, as indicated by the general reference numeral 20, is shown mounted on the undersurface 23 of a support εtructure 22. The εupport εtructure 22 iε typically a deεk or a work εtation. The εupport arm 20 is mounted thereat for movement of a keyboard tray, indicated by the general reference numeral 30, between a plurality of work poεitions, with these work positions each being of a different height so as to allow a user to find an ergonomically correct, comfortable working position of proper height for typing on a keyboard 21 positioned atop the keyboard tray 30 (see Figure 6) . The uppermost work position of the keyboard tray 30 iε εhown in εolid lining in Figure 1, and an intermediate position of the keyboard tray 30 is shown in ghost outline in

Figure 1.

The keyboard tray 30 comprises a keyboard receiving portion 31, a bracket member 32 that iε εecurely affixed to the keyboard receiving portion 31 by way of conventional threaded fasteners (not εhown) , and a connecting member 34 pivotally mounted to the bracket member 32 by means of a pivot pin 33. The bracket member 32 and the connecting member 34 together form a depending portion of the keyboard tray 30. The connecting member 34 is pivotally mounted to the bracket member 34 by meanε of the pivot pin 33, which pin 33 paεεeε through aligned apertures 35 in the connecting member 34, and through aligned apertures 38 located one each in a pair of downwardly depending flange members 37, which

flange members 37 are part of the bracket member 32. In this manner, the keyboard receiving portion 31 iε angularly adjuεtable with reεpect to the connecting member 34 to a εelected orientation. The angle of orientation of the keyboard receiving portion 31 with respect to the connecting member 34 iε locked by the user through manipulation of a handle member 39 (see Figure 2) . The handle member 39 (removed from Figure 1 for ease of illuεtration) threadibly engageε one end 29a a locking εhaft member 29, which εhaft member 29 extends outwardly through an arcuately slotted opening 28 located in one of the flange members 37, to thereby limit the angular travel of the keyboard receiving portion 31 about the pivot pin 33. To adjuεt the angle of orientation of the keyboard receiving portion 31, the handle member 39 is pivoted counter¬ clockwise, as indicated by arrow "E" in Figure 9, thus loosening the threaded engagement of the end 29a εo aε to provide clearance between the flange memberε 37 and the connecting member 34. The keyboard receiving portion 31 is then positioned by the user at the desired angle, as indicated by arrow "F" in Figure 9, and the handle member 39 is tightened by movement in the reverse direction of arrow "E" to lock the keyboard tray 30 at the desired angular orientation.

The connecting member 34 haε a "C"-shaped end bracket member 36 εecurely faεtened thereto at the other oppoεite end thereof that the bracket member 32 iε mounted to, typically by welding. The "C"-εhaped end bracket member 36 comprises a central base portion 25 having an elongate opening 27 therein, with a pair of εubεtantially parallel ear portions 26,26

extending outwardly from the opposite ends of the base portion 25. A plurality of mounting apertures 26a in each of the ear portions 26,26 are adapted to receive threaded fastening members therethrough for mounting of the connecting member 34 to the support arm 20, as will be detailed subsequently.

The manually repositionable support arm 20 compriεeε a mounting frame, aε indicated by the general reference numeral 40, which mounting frame 40 compriεeε a track member 42 that is securely mounted to the underεurface 23 of the support structure 22 by way of conventional mounting means such as wood screws (not shown) , and a carriage member 44 that engages the track member 42 for εlidably εupported travel along the track member 42 in a forward direction from a fully retracted εtowed poεition, aε εhown in Figureε 8 and 11, to a fully extended poεition as shown in Figureε 1, 5, 6, 7, 9, and 10. Similarly, the carriage member 44 iε slidably moveable in a rearward direction along the track member 42 from the fully extended poεition to the fully retracted εtowed position, as will be discuεsed subsequently. When the carriage member 44 is in the fully retracted stowed position, the support arm 20 is removed from being in proximity to a leading edge 24 of the underεurface 23 of the εupport εtructure 22. The fully retracted stowed poεition of the carriage member 44 correεpondε to a fully retracted stowed position of the keyboard tray 30. In contraεt, when the carriage member 44 iε in itε fully extended position, it is placed in relative proximity to the leading edge 24, and the keyboard tray 30 iε poεitioned generally outwardly beyond the leading

edge 24 of the undersurface 23, such that the keyboard 21 (not εhown) placed thereon is readily accessible by a user seated adjacent to the εupport εtructure 22.

The carriage member 44 includeε a flanged plate member 45 and a U-shaped bracket member 46 pivotally mounted to the underεide of flanged plate member 45 by way of hollow rivet 47 (see Figure 1) . The hollow rivet 47 is received and retained in the carriage member 44 through an aperture 48 in the U-shaped bracket member 46 and through an aperture 49 in the flanged plate member 45. The hollow rivet 47 is retained in place by a head portion 47a at one end thereof and by turned-down end portion 47b at the other opposite end thereof. A pin member 41 is operatively retained for sliding movement within a hollow rivet 47 between a latching position, as shown in ghost outline in Figure 5, and a release poεition, as εhown in εolid lining in Figure 5. The operation and purpoεe of the pin member 41 will be detailed εubεequently.

A pair of oppoεed flangeε 45a on the flanged plate member 45 are received and retained in εliding relation within co-operating oppoεed channels 42a, which opposed channels 42a are defined by respective depending "L"-shaped flange portionε 42b of the track member 42, to thereby allow for the aforeεaid εlidably supported travel of the carriage member 44 between its fully retracted εtowed poεition and its fully extended position. An upwardly turned lip member 104 abuts against a stop means in the form of a depending flange member 106 located at the front end of the track member 42, so as to limit the

travel of the carriage member 44 at its fully extended position. A similar lip member and stop means arrangement (not shown) located at the back end of the track member 42 limits the travel of the carriage member 44 at itε fully retracted stowed position.

A first roller member 50 is rigidly mounted on the U-shaped bracket member 46 in fixed relation thereto by way of a plurality of threaded fastenerε (not shown) extending through apertures 46a in the U-shaped bracket member 46 and being received and retained in receiving channels 57, which receiving channels 57 are defined by mounting rib members 56. The mounting rib memberε 56 are integrally formed aε part of the first roller member 50. In this manner, the first roller member 50 iε fixed against rotation relative to the U-shaped mounted bracket 46. The firεt roller member 50 haε a firεt longitudinal axiε 52 and a pair of firεt circumferential bearing εurfaces 54, dispoεed one each adjacent the axially oppoεite ends 50a,50b of the first roller member 50.

A second roller member 60 iε rigidly mounted between the two ear portionε 26,26 of the connecting member 34, by way of a plurality of threaded faεtenerε (not shown) pasεing through apertures 26a in the ear portions 26,26 so as to fix the second roller member 60 against rotation relative to the connecting member 34. These threaded fastenerε are received and retained in the second roller member 60 in receiving channels 67, which receiving channels 67 are defined by mounting rib members 66 integrally formed as part of the second roller member 60. The second

roller member 60 has a second longitudinal axis 62 and a pair of second circumferential bearing surfaces 64 dispoεed one each adjacent the axially opposite endε 60a, 60b of the second roller member 60.

A rigid houεing member 70 εubstantially encases the firεt 50 and the εecond 60 roller memberε in journalled relation about the firεt 54 and second 64 circumferential bearing surfaces so as to hold the first 50 and second 60 roller members in fixed εpaced relation to one another, with the first 52 and second 62 longitudinal axes being parallel one to the other. Annular receiving surfaces 75 on the rigid housing member 70 receive circumferential bearing surfaces 54 of the firεt roller member 50 in rotational relation so as to permit relative rotation of the housing member 70 with reεpect to the firεt roller member 50 about the firεt longitudinal axiε 52. Similarly, annular receiving εurfaceε 76 on the rigid houεing member 70 receive the εecond circumferential bearing εurfaceε 64 of the εecond roller member 60 in rotational relation so as to permit relative rotation of the rigid housing member 70 with respect to the second roller member 60 about the second longitudinal axis 62.

The rigid housing member 70 iε preferably made in two halveε 70a,70b, which halveε 70a,70b are introduced one to the other during aεεembly and are held together by any known faεtening meanε (not εhown) such as nuts and bolts. A cooperating key 78 and notch 79 are preferably formed in the rigid houεing member 70 εo aε to ensure proper alignment of the two halves 70a,70b during aεεembly thereof and εo aε to provide

increased structural rigidity againεt twiεting of the two halves 70a,70b during use. A plurality of cooperating keys and notches, or keys and notches having more complicated profiles, may be incorporated, if desired, but are not shown for the purpose of clarity of illuεtration. A raiεed blocking member 77 is preferably formed in two halves 77a,77b disposed one half each on each side of the joining line of the two halves 70a,70b of the rigid housing member 70. The purpose and function of the blocking member 77 will be discuεεed εubεequently.

A flexible link means in the form of a cloεed loop band 80 iε operatively mounted around the outer circumferential εurfaceε 51 and 61, of the first 50 and second 60 roller members, respectively, in intimate contact therewith. The closed loop band 80 is preferably made from a metal material having a thickness of about 0.004" and having a tenεile εtrength of about 270,000 P.S.I. The cloεed loop band 80 iε in fixed indexed engagement with the firεt 50 and second 60 roller memberε, aε can beεt be seen in Figures 3 and 4. The first 50 and second 60 roller members each have a respective one of a first axially parallel channel 53 and a second axially parallel channel 63 formed in the respective of the outer circumferential surfaceε 51,61 thereof. Firεt 81 and εecond 82 cooperating portions of the closed loop band 80 are each fixedly retained within the respective one of the first 53 and second 63 axially parallel channels by means of first 58 and second 68 elongate roll pinε longitudinally poεitioned one each in their respective ones of the first 53 and second 63 axially parallel channels. The first 58 and

εecond 68 elongate roll pins are positioned in overlying frictionally secured engagement with the respective wallε 55,65 of the axially parallel channelε 53,63, so as to frictionally secure the closed loop band 80 to the first 50 and second 60 roller memberε as discusεed further below.

The firεt 58 and εecond 68 roll pinε are each hollow and each have a reεpective longitudinal split 59,69 therein, so as to be diametrically expandable. Such diametric expansion is caused by engagement of a conventional threaded fastener 88 at each of the axially opposite ends 68a,68b of the second roll pin 68, aε indicated by arrowε "B" in Figure 3, where the conventional threaded faεtenerε 88 are about to be inεerted into the axially oppoεite ends 68a, 68b of the second roll pin 68. The first 58 and second 68 roll pins may be made of plastic material, metal material, or any other suitable material as deemed appropriate through routine engineering calculation. Internal gripping plugs (not shown) may be optionally uεed to facilitate the threading of the threaded faεtenerε 88 depending on the material used for the first 58 and second 68 roll pins. As seen in Figure 4A, the closed loop band 80 is retained loosely within the axially parallel channel 53 of the first roller member 50 before the first roll pin 50 is diametrically expanded. The threaded fastenerε 88 are turned from a poεition aε shown in Figure 4A to a position shown in Figure 4B, thuε advancing the threaded faεtenerε 88, εo aε to diametrically expand the firεt roll pin 58, to thereby cauεe the aforesaid overlying frictionally secure engagement of the firεt roll

pin 58 with the wall 55 of the axially parallel channel 53 through the cloεed loop band 80, aε can beεt be seen in Figure 4B. Similarly, in relation to the first roll member 50, the first roll pin 58 is expanded in a similar manner by analogouε conventional faεtening means (not εhown) εo aε to thereby cauεe the aforeεaid overlying frictionally εecure engagement of the firεt roll pin 58 with the wall 55 of the axially parallel channel 53 through the closed loop band 80.

After both of the firεt 58 and second 68 roll pinε have been diametrically expanded, the cloεed loop band 80 iε in tenεion, and is, in fact, quite tightly retained, within about the first 50 and second 60 roller members εo aε to preclude any εlack in the cloεed loop band 80. Aε can alεo be εeen in Figure 4B, the diametric expansion of the second roll pin 68 causes the closed loop band 80 to tightly span acrosε the longitudinal εplit 69. In this above-described manner, the cloεed loop band 80 iε operatively mounted around the outer circumferential εurfaces 51 and 61 of the first 50 and second 60 roller members, respectively, in fixed indexed engagement therewith so as to εurroundingly link the firεt 50 and second 60 roller members for planetary movement of the second roller member 60 about the first roller member 50 within the rigid housing member 70, as will become more apparent as thiε deεcription proceedε.

It can further be εeen that with this arrangement, as the firεt roller member 50 remains secured against rotation to the mounting frame 40, and as the first 50 and second 60

roller memberε are of the εame diameter aε each other, the second roller member 60 remains at all timeε εubεtantially rotationally aligned with respect to the first roller member 50. Thus, the keyboard tray 30, which is fixed againεt rotation to the second roller member 60, remainε at a conεtant angular orientation upon movement of the rigid housing member around the first roller member 50. In this manner, the keyboard tray 30 can be moved between a plurality of work positionε and remain at a constant angular orientation as initially selected by the user.

A lock means, aε indicated by the general reference numeral 90, iε operatively mounted between the εecond roller member 60 and the rigid housing member 70 by way of the connecting member 34. The lock meanε 90 compriεeε a detent member 92 slidably operatively mounted on the exterior of the connecting member 34 and a plurality of teeth means 94 integrally formed on the outer surface 73 of the rigid housing member 70. The detent member 92 slidably moveε εuch that an end portion 91 thereof extendε into and through the elongate opening 27 in the baεe portion 25 of the "C"-εhaped end bracket member 36, aε indicated by arrow "A" in Figure 2 , so as to selectively engage the plurality of teeth means 94. The detent member 92 has a handle portion 93 εo aε to allow it to be readily hand operable by a uεer. A εpring member 96, having one end 96a operatively connected to a firεt cooperating lug 98 on the detent member 92, and the other end 96b operatively connected to a εecond cooperating lug 99 internally poεitioned on the connecting member 34, biases the detent member 92 into engagement with the plurality of teeth means 94. When the

detent member 92 is engaged with the teeth means 94, the lock means 90 selectively precludes the relative rotation of the rigid housing member 70 with respect to the second roller member 60, thereby to selectively lock the keyboard tray 30 attached to the second roller member 60 in any one of a plurality of user chosen work positions. Alternatively, the lock means 90 could be operatively mounted (not shown) between the first roller member 50 and the rigid housing member 70, in a generally analogous manner.

A spring means in the form of a pair of co¬ acting εpring memberε 86, iε operatively interconnected between the mounting frame 40 and the rigid houεing member 70. Preferably, each εpring member 86 extendε into the interior of the firεt roller member 50 through respective openings 85 (only one is shown - εee Figure 3) in the outer circumferential εurface 51 of the firεt roller member 50, εuch that one end 86a of each of the εpring members 86 operatively engageε an internal rib member 87 axially dispoεed within the firεt roller member 50. The other end 86b of each of the spring members 86 operatively engages a protruding lug 71 on the inner surface 74 of the rigid housing member 70 (which lug may be a bolt member εpanning the interior of the housing member 70 so aε to assist in joining together the two housing halves 70a,70b. The spring members 86 bias the keyboard tray 30 upwardly so as to counteract the weight of the keyboard tray 30, the rigid housing member 70, the contained components, and the keyboard 21.

The pin member 41 is part of a latching mechanism, for the carriage member 44, which

latching member is indicated by the general reference numeral 100. The latching mechanism 100 is operatively mounted between the track member 42 and the carriage member 44. The latching mechanism 100 provides for latching of the carriage member 44 in its fully extended position, and alεo for automatic unlatching of the carriage member 44 from itε fully extended poεition when the keyboard tray 30 iε moved to a predetermined limited one of itε plurality of work poεitionε, (aε beεt shown in ghost outline in Figure 1) whereafter the carriage member 44 iε permitted to travel towardε its fully retracted stowed position for stowage of the keyboard tray 30.

The pin member 41 is operatively retained on the carriage member 44, as aforeεaid, for εliding movement between a latching poεition and a releaεe poεition. At the fully extended poεition, εhown in εolid outline in Figure 1 and in phantom outline in Figure 5, the pin member 41 iε εpring biaεed upwardly by a biasing spring 43 to the latching poεition εhown, εo aε to engage a camming surface 102 on the track member 42. In all of the available work positions of the keyboard tray 30, except the predetermined limited work poεition shown in ghost outline in Figure 1 and in solid lining in Figure 5, the pin member 41 is precluded from slidably moving from its latching position to itε releaεe poεition by meanε of the blocking member 77 on the rigid housing member 70. Accordingly, the carriage member 44 iε latched in itε fully extended poεition. When the keyboard tray 30 iε in the predetermined limited work position, the blocking member 77 no longer precludes the downwardly

εlidable travel of the pin member 41. When the carriage member 44 iε initially moved rearwardly, the head portion 41a engageε the cam member 102 and iε thereby cauεed to travel downwardly to its lower release position, as indicated by arrow "C" in Figure 5. Accordingly, the head portion 41a of the pin member 41 is permitted to pass by the cam member 102 on the track member 42, thus permitting travel of the carriage member 44 in the opposite rearward direction, as indicated by arrow "D" in Figure 5, to its fully retracted εtowed poεition.

In use, to move the keyboard tray 30 from a relatively raised work position, as beεt εeen in Figureε 6 and 10, to a relatively lowered predetermined one of itε work poεitionε, and then to itε fully retracted εtowed poεition, aε best shown in Figures 8 and 11, the handle portion 93 of the detent member 92 is pulled toward the user against the biaε of the spring member 96, such that the end portion 91 of the detent member 92 is removed from contact with the teeth means 94 of the lock means 90. The keyboard tray 30 iε then lowered to itε predetermined limited work poεition, aε beεt εeen in Figure 7, the handle portion 93 iε released so as to permit the end portion 91 of the detent member 92 to re-engage the teeth meanε 94, thereby locking the keyboard tray 30 in thiε poεition. The keyboard tray 30 is then slid rearwardly so as to travel towards itε fully retracted εtowed position. Such movement of the keyboard tray 30 from a relatively raised work position to itε fully retracted εtowed position may be εubεtantially continuous, and is indicated by arrow "G" in Figure 10.

Converεely, to move the keyboard tray 30 from its fully retracted stowed poεition, aε beεt seen in Figures 8 and 11, to a relatively raised work position, as beεt seen in Figures 1, 5, 6, 9 and 10, the keyboard tray 30 is pulled toward the leading edge 24 of the support structure 22 until the carriage member 44 reaches its fully extended position, with the keyboard tray 30 still in a predetermined limited one of itε work poεitions, as best εhown in Figure 7. The handle portion 93 of the detent member 92 iε then pulled toward the uεer against the bias of the spring member 96, such that the end portion 91 of the detent member 92 iε removed from contact with the teeth meanε 94 of the lock meanε 90. The keyboard tray 30 is then moved to a user chosen relatively raised work poεition, whereat the handle portion 93 iε releaεed εo aε to permit the end portion 91 of the detent member 92 to re- engage the teeth means 94, thereby locking the keyboard tray 30 in the aforeεaid uεer choεen relatively raiεed work poεition.

An alternative preferred embodiment of the preεent invention that iε εpecifically deεigned to accommodate a notebook type of microcomputer

120 will now be deεcribed with reference to

Figures 12 through 14. Thiε alternative embodiment functions in generally the εame manner aε doeε the embodiment of Figureε 1 through 11, but certain key componentε are shaped and configured differently than in the aforedeεcribed embodiment, εo aε to accommodate a notebook type microcomputer 120. Accordingly, only the additional or different features of this alternative preferred embodiment will be subsequently described herein. In this

alternative embodiment, analogous structureε εimilar or identical to thoεe found in the preferred embodiment will be εimilarly numbered, with the prime εymbol (') placed thereafter.

The εupport arm 20' is mounted to the undersurface 23' of the support structure 22', in the εame manner aε in the firεt deεcribed embodiment. The carriage member 44' of the mounting frame 40' and the connecting member 34' of the keyboard tray 30' are each shaped and dimensioned such that the first longitudinal axiε 52' of the first roller member 50' is disposed above and forwardly of the second longitudinal axis 62' of the εecond roller member 60' when the keyboard tray 30' is in its relatively raised work position, as shown in Figure 12, and iε diεposed generally directly above and slightly forwardly of the second longitudinal axis 62' as defined by the orientation of the rigid houεing member 70' when the keyboard tray 30' iε in its relatively lowered work position, aε shown in Figure 13. When the keyboard tray 30' is moved from its relatively raised work position, as εhown in Figure 12, to itε relatively lowered work position, aε εhown in Figure 13, the εecond longitudinal axiε 62' of the εecond roller member 60' moveε downwardly and forwardly. When the keyboard tray 30' iε moved from itε relatively lowered work poεition, as shown in Figure 13, to its relatively raised work position, as shown in Figure 12, the second longitudinal axis 62' moves upwardly and rearwardly. Such downward and forward, or upward and rearward, movement of the second longitudinal axis 62' permits movement of the keyboard tray 30' in an arc that is εimilarly directed to the plane of the diεplay screen 122

of the notebook microcomputer 120. In thiε manner, a preferred poεition of the notebook microcomputer 120 may be realized, without the leading edge 24' of the support structure 22' contacting the rear of the display screen 122, so as to thereby avoid cauεing the diεplay screen 122 to close or partially cloεe upon or during such contact. Because of the different geometry of the embodiment of Figures 12-15, the lock meanε 90' of the device iε εignificantly modified, and iε, in fact, εo ewhat simplified. Thus, the locking means 90' of the preferred embodiment eεεentially compriεes a detent member 115, having an engaging end portion 115a and a handle portion 117. The detent member 115 iε pivotally operatively mounted about a pivot pin 121 which εpanε the diεtance between the ear portionε 26' of the end bracket member 36', εo aε to εelectively engage and diεengage the teeth means 94' on the rigid housing member 70' upon manual manipulation of the handle portion 117 by the user. The engaging end portion 115a of the detent member 115 is biased into engagement with the teeth means 94' by way of a torsion εpring (not εhown) , which torsion spring operatively surrounds the pivot pin 121 to thereby lock the εupport arm 20' in a εelected angular orientation and the alεo thereby lock the keyboard tray 30' in a εelected work poεition.

Figure 14 εhows the keyboard tray 30' supporting the notebook microcomputer 120 in a fully retracted stowed position such that the notebook microcomputer 120 iε located generally under the support εtructure 22'. In order to reach thiε fully retracted εtowed position from the fully extended position shown in Figure 12,

whereat the keyboard tray 30' iε in a relatively raiεed work position, the display screen 122 must, of courεe, firεt be cloεed. The support arm 20' is then slid rearwardly until the carriage member 44' reaches itε fully retracted stowed position.

It haε been found that a typical notebook microcomputer 120 iε readily removed from the keyboard tray 30' due to itε εlim and compact εize and εhape. Where such removal is unauthorized by its owner, it is highly undesirable. In a further preferred aspect of the embodiment shown in Figures 12 through 14, a means is discloεed for locking the keyboard tray 30' in its fully retracted stowed position, so as to preclude εuch unauthorized removal of or other tampering of the notebook type of microcomputer 120, will now be diεcuεεed with reference to Figures 15 through 19.

As can best be seen in Figures 16 through 19, direct accesε to the notebook microcomputer 120, when the keyboard tray 30' iε in itε fully retracted stowed position, iε precluded from the two εideε of the keyboard tray 30' by way of a pair of opposed side guard members, as indicated by the general reference numeral 130. Each side guard memberε 130 comprises a selectively movable guard portion 132 pivotally mounted, by way of a hinge member 134, to a frame portion 136, which frame portion 136 is rigidly affixed to the undersurface 23' of the support structure 22' by conventional threaded fastening means, such as wood screws, (not shown) , for generally vertical pivotal movement of the movable guard portion 132 between a raised stowed position, as shown in

εolid lining in Figure 17, and a lowered in-uεe poεition, as shown in Figure 18 in solid lining and as shown in Figure 17 in ghost outline. The pivotal movement of each of the movable guard portionε 132 between their reεpective raised stowed positions and their respective lowered in- use positionε iε indicated in Figure 15 by the two arrows "H" and is indicated in Figure 17 by arrow "I". In each side guard member 130, one end 138a of a εpring member 138 passeε through an aperture 133 in the movable guard portion 132. When the movable guard portion 132 is in its raiεed stowed position, the end 138a of the spring member 138 engages an outer surface portion 137 of the movable guard portion 132 in order to bias the movable guard portion 132 toward its raised εtowed poεition. When the movable guard portion 132 iε in its lowered in- uεe poεition, the end 138a of the spring member 138 engages a top edge portion 135 of the movable guard portion 132 in order to bias the movable guard portion 132 to its lowered in-uεe position. The oppoεite other end 138b of the spring member 138 is secured to the underside of the mounting frame portion 136. The raised stowed position is desirable, aε it precludeε the movable guard portionε 132 of the guard memberε 130 from interfering with the kneeε or upper legε of a user who is εitting at the deεk or work εtation and uεing the notebook microcomputer 120. Further, it permits the support arm 20' to pivotally moved to underneath the support structure 22', which may be desirable on a temporary basis.

A conventional key operated securing lock (similar to those uεed with εimple filing

cabinets) having εecuring lock portion 110, a locking cylinder 126 mounted thereon, and a locking cam 113 rotatably protruding from the locking cylinder 126, is operatively engagable between the keyboard receiving portion 31' of the keyboard tray 30' and the support structure 22' so as to lock the keyboard tray 30' in place. The carriage member 44' muεt be in a retracted poεition, preferably itε fully retracted εtowed poεition, and the keyboard tray 30' εhould be in a relatively raised work position, for the securing lock portion 110 to be engagable. The securing lock portion 110 is shown in section in Figure 19 for clarity of illuεtration, and comprises a lower "L"- shape arm portion 112 and an upper flange 116. As is best seen in Figure 19, the lower arm portion 112 of the securing lock portion 110 hooks around a cooperating lip portion 114 formed in the leading edge of the keyboard receiving portion 31' of the keyboard tray 30'. The upper flange 116 of the securing lock portion 110 engages an opening 118 dispoεed between and defined by the bottom εurface of the track member 42' and an elongate "U" εhaped spanning member 119, which spanning member 119 is also shown in section in Figure 19 for clarity of illustration. The spanning member 119 iε securely fastened to the two depending "L"-shaped flange portions 42b' of the track member 42' by meanε of machine εcrewε (not εhown) . The εpanning member 119 iε εecured in place after the carriage member 44' haε been engaged in the track member 42' .

In order to inεert the εecuring lock portion 110, the lower arm 112 iε hooked around the lip portion of the 114 of the keyboard receiving

portion 31' of the keyboard tray 30', and the upper arm 116 iε then inserted into the opening 118. Once the securing lock portion 110 iε in place in this manner, a conventional key iε inεerted into the key slot 117 of the locking cylinder 126, and is used to turn the locking cam 113 in a direction as indicated by arrow "J" in Figure 19, thus locking the securing lock portion 110 in place. In thiε manner, the keyboard tray 30' iε locked in cloεely held secured relation to the undersurface 23' of the εupport structure 22' .

In a further alternative embodiment (not shown) , it is contemplated that the support arm 70 or 70' could be configured such that a spring means biaseε the εupport arm between a raiεed work position and a extended and retracted position in an over-the-center manner.

Aε uεed in this specification, the term "circumferential bearing surfaceε" expreεεly includeε bearing surfaces of any diameter, whether the same as, smaller than or larger than the diameter of the respective roller member with which a particular circumferential bearing surface is aεsociated.

Also as used in this εpecification, the term "keyboard tray" meanε any type of support tray, whether specifically adapted by size or shape to εupport a microcomputer keyboard, a notebook microcomputer, a typewriter, or any other εimilar or related device.