CA2117169C

CA2117169C - Adjustable support arm for keyboard tray

Info

Publication number: CA2117169C
Application number: CA002117169A
Authority: CA
Inventors: Lawrie Mcintosh
Original assignee: Waterloo Furniture Components Ltd
Current assignee: Waterloo Furniture Components Ltd
Priority date: 1994-03-07
Filing date: 1994-03-07
Publication date: 1998-11-24
Anticipated expiration: 2014-03-07
Also published as: CA2117169A1; WO1997008974A1

Abstract

A manually repositionable support arm mountable on a support structure for movement of a keyboard tray between a plurality of work positions is disclosed. The device comprises a mounting frame, a first roller member that is rigidly mounted on the mounting frame in fixed relation thereto, and a second roller member that is rigidly mounted on a depending portion of the keyboard tray in fixed relation thereto. A rigid housing substantially encases the first and second roller members in journalled relation about respective first and second circumferential bearing surfaces on the first and second roller members 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 with respect to the first and second roller members. A constant length closed-loop band is operatively mounted around both of the first and second roller members in fixed indexed engagement therewith so as 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 housing, such that the second roller member remains substantially rotationally aligned with respect to the first roller member. A lock is operatively mounted between the second roller member and the rigid housing member to selectively preclude the relative rotation of the second roller member with respect to the rigid housing, which, in turn, selectively locks the keyboard tray in any one of said plurality of work positions.

Description

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~FIELD OF THE INVENTION

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.

BACRGROUND OF THE l~.v~ ON

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 ~ ~7~
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.

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 211 ~ ~J~

l~y 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.

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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 as 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.

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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 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.

SUMMARY OF THE l..v~..lON

In accordance with the present invention-there is disclosed a manually repositionable support arm mountable on a 2 ~ 9 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 structure, 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 housing 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 so as 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 housing member, such that the second roller member remains substantially rotationally aligned with respect to the first roller member during such planetary movement. There is also provided a lock means operatively mounted between a selected one of the first and second roller members and the rigid housing member to selectively preclude the relative rotation of the selected one .i .
-k ~ 9 '_ of the first and second roller members with respect to the rigidhousing member, thereby to selectively lock the keyboard tray attached to the second roller member in any one of the plurality of work positions.

s Other advantages, 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 parts 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 described hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a side 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 shown in ghost outline in a predetermined relatively lowered work position, with portions omitted for the sake of clarity;

Figure 2 is an exploded perspective view of the support arm of Figure l;

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

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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;

5Figure 4B is a view similar to Figure 4A, with the roll pin diametrically expanded;

Figure 5 is a side elevational view of a portion of the rigid housing member and a portion of the slidable coupled track 10members 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;

20Figure 8 is a diagrammatic side 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 25view of the support arm of Figure 6, showing the keyboard tray and a portion of the rigid housing member;

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Figure 10 is 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 is in a fully retracted stowed position;

Figure 12 is a side 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 ease of illustration;

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 position;

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;

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~~~ Figure 16 is an enlarged perspective view of the embodiment of Figure 15, showing only a portion of a computer work station, with the keyboard tray shown locked according to said further aspect 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 details of said further preferred aspect of the present invention;

Figure 18 is 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.

DET~TT~n DESCRIPTION OF A PREFERRED EMBODIMENT

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 structure 22. The support structure 22 is typically a desk or a work station. The support arm 20 is mounted thereat for movement of a keyboard tray, indicated by the general reference numeral 30, between a plurality of work positions, 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 is shown in solid 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 is securely affixed to the keyboard receiving portion 31 by way of conventional threaded fasteners (not shown), 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 means of the pivot pin 33, which pin 33 passes 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 is angularly adjustable with respect to the connecting member 34 to a selected orientation. The angle of orientation of the keyboard receiving portion 31 with respect to the connecting member 34 is 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 illustration) threadibly engages one end 29a a locking shaft member 29, which shaft 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 adjust 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 so as to provide clearance between the flange members 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 has a "C"-shaped end bracket member 36 securely fastened thereto at the other opposite end thereof that the bracket member 32 is mounted to, typically by welding. The "C"-shaped end bracket member 36 comprises a central base portion 25 having an elongate opening 27 therein, with a pair of substantially 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 comprises a mounting frame, as indicated by the general reference numeral 40, which mounting frame 40 comprises a track member 42 that is securely mounted to the undersurface 23 of the support structure 22 by way of conventional mounting means such as wood screws (not ~ ~ ~ 7 ~ ~ ~

own), and a carriage member 44 that engages the track member 42 for slidably supported travel along the track member 42 in a forward direction from a fully retracted stowed position, as shown in Figures 8 and 11, to a fully extended position as shown in Figures 1, 5, 6, 7, 9, and 10. Similarly, the carriage member 44 is slidably moveable in a rearward direction along the track member 42 from the fully extended position to the fully retracted stowed position, as will be discussed 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 undersurface 23 of the support structure 22. The fully retracted stowed position of the carriage member 44 corresponds to a fully retracted stowed position of the keyboard tray 30. In contrast, when the carriage member 44 is in its fully extended position, it is placed in relative proximity to the leading edge 24, and the keyboard tray 30 is positioned generally outwardly beyond the leading edge 24 of the undersurface 23, such that the keyboard 21 (not shown) placed thereon is readily accessible by a user seated adjacent to the support structure 22.

The carriage member ~4 includes a flanged plate member 45 and a U-shaped bracket member 46 pivotally mounted to the underside 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 position, as shown in solid lining in Figure 5. The operation and purpose of the pin member 41 will be detailed subsequently.

A pair of opposed flanges 45a on the flanged plate member 45 are received and retained in sliding relation within co-operating opposed channels 42a, which opposed channels 42a are defined by respective depending "L"-shaped flange portions 42b of the track member 42, to thereby allow for the aforesaid slidably supported travel of the carriage member 44 between its fully retracted stowed position 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 its 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 aplurality of threaded fasteners (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 members 56 are integrally formed as part of the first roller member 50. In this manner, the first roller member 50 is fixed against rotation relative to the U-shaped mounting bracket 46.
The first roller member 50 has a first longitudinal axis 52 and a pair of first circumferential bearing surfaces 54, disposed one each adjacent the axially opposite ends 50a,50b of the first roller member 50.

A second roller member 60 is rigidly mounted between the two ear portions 26,26 of the connecting member 34, by way of a plurality of threaded fasteners (not shown) passing 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 fasteners 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 disposed one each adjacent the axially opposite ends 60a,60b of the second roller member 60.

A rigid housing member 70 substantially encases the first 50 and the second 60 roller members in journalled relation about the first 54 and second 64 circumferential bearing surfaces so as to hold the first 50 and second 60 roller members in fixed spaced 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 first roller member 50 in rotational relation so as to permit relative rotation of ~, ~ 7 ~
~Ehe housing member 70 with respect to the first roller member 50 about the first longitudinal axis 52. Similarly, annular receiving surfaces 76 on the rigid housing member 70 receive the second circumferential bearing surfaces 64 of the second 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 is preferably made in two halves 70a,70b, which halves 70a,70b are introduced one to the other during assembly and are held together by any known fastening means (not shown) such as nuts and bolts. A
cooperating key 78 and notch 79 are preferably formed in the rigid housing member 70 so as to ensure proper alignment of the two halves 70a,70b during assembly thereof and so as to provide increased structural rigidity against twisting 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 illustration. A raised 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 discussed subsequently.

A flexible link means in the form of a closed loop band is operatively mounted around the outer circumferential surfaces 51 and 61, of the first 50 and second 60 roller members, ~ ~ ~ 7 i ~ ~9 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 tensile strength of about 270,000 P.S.I. The closed loop band 80 is in fixed indexed engagement with the first 50 and second 60 roller members, as can best 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 surfaces 51,61 thereof. First 81 and second 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 pins longitudinally positioned one each in their respective ones of the first 53 and second 63 axially parallel channels. The first 58 and second 68 elongate roll pins are positioned in overlying frictionally secured engagement with the respective walls 55,65 of the axially parallel channels 53,63, so as to frictionally secure the closed loop band 80 to the first 50 and second 60 roller members as discussed further below.

The first 58 and second 68 roll pins are each hollow and each have a respective 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, as indicated by arrows "B" in Figure 3, where the conventional threaded fasteners 88 are about to be inserted into ~ 7~
he axially opposite 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 used to facilitate the threading of the threaded fasteners 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 fasteners 88 are turned from a position as shown in Figure 4A to a position shown in Figure 4B, thus advancing the threaded fasteners 88, so as to diametrically expand the first roll pin 58, to thereby cause the aforesaid overlying frictionally secure engagement of the first roll pin 58 with the wall 55 of the axially parallel channel 53 through the closed loop band 80, as can best 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 analogous conventional fastening means (not shown) so as to thereby cause the aforesaid overlying frictionally secure engagement of the first roll pin 58 with the wall 55 of the axially parallel channel 53 through the closed loop band 80.

After both of the first 58 and second 68 roll pins have been diametrically expanded, the closed loop band 80 is in tension, and is, in fact, quite tightly retained, within about the first 50 and second 60 roller members so as to preclude any slack in the closed loop band 80. As can also be seen in Figure 4B, the diametric expansion of the second roll pin 68 causes the closed loop band 80 to tightly span across the longitudinal split 69. In this above-described manner, the closed loop band 80 is operatively mounted around the outer circumferential surfaces 51 and 61 of the first 50 and second 60 roller members, respectively, in fixed indexed engagement therewith so as to surroundingly link the first 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 this description proceeds.

It can further be seen that with this arrangement, as the first roller member 50 remains secured against rotation to the mounting frame 40, and as the first 50 and second 60 roller members are of the same diameter as each other, the second roller member 60 remains at all times substantially rotationally aligned with respect to the first roller member 50. Thus, the keyboard tray 30, which is fixed against rotation to the second roller member 60, remains at a constant 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 positions and remain at a constant angular orientation as initially selected by the user.

A lock means, as indicated by the general reference numeral 90, is operatively mounted between the second roller member 60 and the rigid housing member 70 by way of the connecting member 34. The lock means 90 comprises 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 moves such that an end portion 91 thereof extends into and through the elongate opening 27 in the base portion 25 of the "C"-shaped end bracket member 36, as 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 so as to allow it to be readily hand operable by a user. A spring member 96, having one end 96a operatively connected to a first cooperating lug 98 on the detent member 92, and the other end 96b operatively connected to a second cooperating lug 99 internally positioned 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 spring members 86, is operatively interconnected between the mounting frame 40 and the rigid housing member 70. Preferably, 21 ~7~
each spring member 86 extends into the interior of the first roller member 50 through respective openings 85 (only one is shown - see Figure 3) in the outer circumferential surface 51 of the first roller member 50, such that one end 86a of each of the spring members 86 operatively engages an internal rib member 87 axially disposed within the first 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 spanning the interior of the housing member 70 so as 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 also for automatic unlatching of the carriage member 44 from its fully extended position when the keyboard tray 30 is moved to a predetermined limited one of its plurality of work positions, (as best shown in ghost outline in Figure 1) whereafter the carriage member 44 is permitted to travel towards 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 aforesaid, for sliding movement between a latching position and a release position. At the fully extended position, shown in solid outline in Figure 1 and in phantom outline in Figure 5, the pin member 41 is spring biased upwardly by a biasing spring 43 to the latching position shown, so as 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 position 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 its release position by means of the blocking member 77 on the rigid housing member 70. Accordingly, the carriage member 44 is latched in its fully extended position. When the keyboard tray 30 is in the predetermined limited work position, the blocking member 77 no longer precludes the downwardly slidable travel of the pin member 41. When the carriage member 44 is initially moved rearwardly, the head portion 41a engages the cam member 102 and is thereby caused to travel downwardly to its lower release position, as indicated by arrow "C" in Figure 5. Accordingly, the head portion 4la 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 stowed position.

In use, to move the keyboard tray 30 from a relatively raised work position, as best seen in Figures 6 and 10, to a 2I~ 71 ~
relatively lowered predetermined one of its work positions, and then to its fully retracted stowed position, as best shown in Figures 8 and 11, the handle portion 93 of the detent member 92 is pulled toward the user against the bias 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 is then lowered to its predetermined limited work position, as best seen in Figure 7, the handle portion 93 is released so as 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 this position. The keyboard tray 30 is then slid rearwardly so as to travel towards its fully retracted stowed position. Such movement of the keyboard tray 30 from a relatively raised work position to its fully retracted stowed position may be substantially continuous, and is indicated by arrow "G" in Figure 10.

Conversely, to move the keyboard tray 30 from its fully retracted stowed position, as best seen in Figures 8 and 11, to a relatively raised work position, as best 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 its work positions, as best shown in Figure 7. The handle portion 93 of the detent member 92 is then pulled toward the user against the bias 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 2 1 ~ 7 ~
-lock means 90. The keyboard tray 30 is then moved to a user chosen relatively raised work position, whereat the handle portion 93 is released so as 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 aforesaid user chosen relatively raised work position.

An alternative preferred embodiment of the present invention that is specifically designed to accommodate a notebook type of microcomputer 120 will now be described with reference to Figures 12 through 14. This alternative embodiment functions in generally the same manner as does the embodiment of Figures 1 through 11, but certain key components are shaped and configured differently than in the aforedescribed embodiment, so as 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 structures similar or identical to those found in the preferred embodiment will be similarly numbered, with the prime symbol (') placed thereafter.

The support arm 20' is mounted to the undersurface 23' of the support structure 22', in the same manner as in the first described 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 axis 52' of the first roller member 50' is disposed above and 7 ~ ~ ~
'_ forwardly of the second longitudinal axis 62' of the second roller member 60' when the keyboard tray 30' is in its relatively raised work position, as shown in Figure 12, and is disposed generally directly above and slightly forwardly of the second longitudinal axis 62' as defined by the orientation of the rigid housing member 70' when the keyboard tray 30' is in its relatively lowered work position, as shown in Figure 13. When the keyboard tray 30' is moved from its relatively raised work position, as shown in Figure 12, to its relatively lowered work position, as shown in Figure 13, the second longitudinal axis 62' of the second roller member 60' moves downwardly and forwardly.
When the keyboard tray 30' is moved from its relatively lowered work position, 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 similarly directed to the plane of the display screen 122 of the notebook microcomputer 120. In this manner, a preferred position 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 causing the display screen 122 to close or partially close upon or during such contact. Because of the different geometry of the embodiment of Figures 12-15, the lock means 90' of the device is significantly modified, and is, in fact, somewhat simplified. Thus, the locking means 9o' of the preferred embodiment essentially comprises a detent member 115, having an engaging end portion 115a and a handle portion 117.
The detent member 115 is pivotally operatively mounted about a pivot pin 121 which spans the distance between the ear portions 26' of the end bracket member 36', so as to selectively engage and disengage 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 spring (not shown), which torsion spring operatively surrounds the pivot pin 121 to thereby lock the support arm 20' in a selected angular orientation and the also thereby lock the keyboard tray 30' in a selected work position.

Figure 14 shows the keyboard tray 30' supporting the notebook microcomputer 120 in a fully retracted stowed position such that the notebook microcomputer 120 is located generally under the support structure 22'. In order to reach this fully retracted stowed position from the fully extended position shown in Figure 12, whereat the keyboard tray 30' is in a relatively raised work position, the display screen 122 must, of course, first be closed. The support arm 20' is then slid rearwardly until the carriage member 44' reaches its fully retracted stowed position.

It has been found that a typical notebook microcomputer 120 is readily removed from the keyboard tray 30' due to its slim and compact size and shape. Where such removal is unauthorized by its owner, it is highly undesirable. In a further preferred 7 ~ ~ ~
aspect of the embodiment shown in Figures 12 through 14, a means is disclosed for locking the keyboard tray 30' in its fully retracted stowed position, so as to preclude such unauthorized removal of or other tampering of the notebook type of microcomputer 120, will now be discussed with reference to Figures 15 through 19.

As can best be seen in Figures 16 through 19, direct access to the notebook microcomputer 120, when the keyboard tray 30' is in its fully retracted stowed position, is precluded from the two sides 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 members 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 solid lining in Figure 17, and a lowered in-use position, 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 portions 132 between their respective raised stowed positions and their respective lowered in-use positions is 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 spring member 138 passes through an aperture 133 in the movable guard portion 132. When the movable guard portion 132 2 1 ~ ~, r' ~

lS in its raised 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 stowed position. When the movable guard portion 132 is in its lowered in-use position, 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-use position. The opposite other end 138b of the spring member 138 is secured to the underside of 10 the mounting frame portion 136. The raised stowed position is desirable, as it precludes the movable guard portions 132 of the guard members 130 from interfering with the knees or upper legs of a user who is sitting at the desk or work station and using the notebook microcomputer 120. Further, it permits the support 15 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 used with simple filing cabinets) having securing lock 20 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 25 member 44' must be in a retracted position, preferably its fully retracted stowed position, and the keyboard tray 30' should be in a relatively raised work position, for the securing lock portion 110 to be engagable. The securing lock portion 110 is g shown in section in Figure 19 for clarity of illustration, 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 disposed between and defined by the bottom surface of the track member 42' and an elongate "U" shaped spanning member 119, which spanning member 119 is also shown in section in Figure 19 for clarity of illustration. The spanning member 119 is securely fastened to the two depending "L"-shaped flange portions 42b' of the track member 42' by means of machine screws (not shown). The spanning member 119 is secured in place after the carriage member 44' has been engaged in the track member 42'.

In order to insert the securing lock portion 110, the lower arm 112 is hooked around the lip portion of the 114 of the keyboard receiving portion 31' of the keyboard tray 30', and the upper arm 116 is then inserted into the opening 118. Once the securing lock portion 110 is in place in this manner, a conventional key is inserted 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 this manner, the keyboard tray 30' is locked in closely held secured relation to the undersurface 23' of the support structure 22'.

f ~
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 biases the support arm between a raised work position and a extended and retracted position in an over-the-center manner.

As used in this specification, the term "circumferential bearing surfaces" expressly includes 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 associated.

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

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A manually repositionable support arm mountable on a support structure for movement of a keyboard tray between a plurality of work positions, said device comprising:

a mounting frame adapted for said mounting on said support structure;

a first roller member having a first longitudinal axis, an outer circumferential surface, and one or more first circumferential bearing surfaces, said first roller member being rigidly mounted on said mounting frame in fixed relation thereto;

a second roller member having a second longitudinal axis substantially parallel to said first longitudinal axis, an outer circumferential surface, and one or more second circumferential bearing surfaces, said second roller member being rigidly mounted on a depending portion of said keyboard tray in fixed relation thereto;

a rigid housing member substantially encasing said first and second roller members in journalled relation about said first and second circumferential bearing surfaces so as to hold said first and second roller members in fixed spaced relation to one another and so as to permit relative rotation of said housing member with respect to said first and second roller members about the respective of said first and second longitudinal axes;

a flexible link means operatively mounted around both of said first and second roller members in fixed indexed engagement therewith so as to surroundingly link said first and second roller members for planetary movement of said second roller member about said first roller member within the rigid housing member, such that said second roller member remains substantially rotationally aligned with respect to said first roller member during said planetary movement; and, lock means operatively mounted between a selected one of said first and second roller members and said rigid housing member to selectively preclude the relative rotation of said selected one of said first and second roller members with respect to said rigid housing member, thereby to selectively lock said keyboard tray attached to said second roller member in any one of said plurality of work positions.

2. The support arm of claim 1, wherein said first and second circumferential bearing surfaces on each roller member are disposed one each adjacent the axially opposite ends of said first and second roller members.

3. The support arm of claim 2, wherein said flexible link means is a constant length closed-loop band operatively mounted around the outer circumferential surface of each of said first and second roller members in intimate contact therewith.

4. The support arm of claim 3, wherein said constant length closed-loop band is positioned between said circumferential bearing surfaces.

5. The support arm of claim 4, wherein said first and second roller members have respective first and second axially parallel channels formed one each as radial indentations in the outer circumferential surface of the respective roller member, and wherein a first and a second co-operating portion of said closed-loop band are each fixedly retained within the respective one of said first and second channels by means of first and second elongate roll pins longitudinally positioned one each in said parallel channels in overlying frictionally secured engagement with said channels.

6. The support arm of claim 5, wherein said first and second roll pins each have a longitudinal split therein so as to be diametrically expandable to thereby cause said overlying frictionally secured engagement of said roll pins with the respective walls of said channels.

7. The support arm of claim 6, further comprising a spring means operatively interconnected between said mounting frame and said rigid housing member so as to bias said keyboard tray upwardly when said support arm is mounted to an undersurface of said support structure.

8. The support arm of claim 7, wherein said spring means comprises a pair of co-acting spring members, with one end of each of said spring members operatively engaging an internal rib member axially disposed within said first roller member and the other opposite end of said spring members operatively engaging an inner surface of said rigid housing member.

9. The support arm of claim 8, wherein said lock means is operatively mounted between said second roller member and said rigid housing member.

10. The support arm of claim 9, wherein said lock means comprises a detent member slidably operatively mounted on said depending portion of said keyboard tray for selectively engaging a plurality of teeth means integrally formed on an outer surface of said housing member.

11. The support arm of claim 10, wherein said mounting frame comprises a track member being adapted for secure mounting to an undersurface of said support structure, and a carriage member engaging said track member for slidably supported travel along said track member in a forward direction from a fully retracted stowed position, whereat said support arm is removed from proximity to a leading edge of said undersurface, to a fully extended position whereat said support arm is placed in relative proximity to said leading edge.

12. The support arm of claim 11, further comprising a latching mechanism operatively mounted between said track member and said carriage member to thereby permit latching of said carriage member in said fully extended position and to permit automatic unlatching of said carriage member from said fully extended position of the carriage member when said keyboard tray is moved to a predetermined limited one of said plurality of work positions, thereafter to permit travel of the carriage member in an opposite rearward direction.

13. The support arm of claim 12, wherein said latching mechanism comprises a spring biased pin member operatively retained on said carriage member for sliding movement when said carriage member is in said fully extended position, between a latching position whereat said pin member engages a cam member on said track member to thereby latch said carriage member in said fully extended position and a release position whereat said pin member no longer engages said cam member so as to thereby preclude, wherein said pin member is selectively retained in said latching position by means of a blocking member on said housing member except when said keyboard tray is in said predetermined limited one of said work positions.

14. The support arm of claim 13, wherein said depending portion of said keyboard tray comprises a connecting member having ear portions rigidly attached one each against rotation to said axially opposite ends of said second roller member.

15. The support arm of claim 14, wherein said detent member is operatively mounted within said connecting member.

16. The support arm of claim 15, wherein, when said support arm is mounted to the undersurface of said support structure, as aforesaid, said carriage member of said mounting frame and said bracket member of said keyboard tray are shaped and dimensioned such that said first longitudinal axis of said first roller member is disposed above and forwardly of said second longitudinal axis of said second roller member so that said second roller member is movable from its lowest work position upwardly and rearwardly to its highest work position.

17. The support arm of claim 16, wherein said carriage member is shaped and dimensioned so as to retain said first roller member forwardly of said leading edge of said undersurface of said support structure when said carriage member is in said fully extended position.

18. The support arm of claim 17, further comprising a key operated securing lock operatively engagable between said keyboard tray and said support structure when said carriage member is in said fully retracted stowed position and said keyboard tray is in a predetermined one of said plurality of work positions, to thereby lock said keyboard tray in closely held secured relation to said undersurface.

19. The support arm of claim 3, wherein said constant length closed-loop band is made from a metal material having a thickness of about 0.004".

20. The support arm of claim 19, wherein said constant length closed-loop band is made from a metal material having a tensile strength of about 270,000 p.s.i.