GB2230946A - Adjustable CRT support stand - Google Patents

Abstract

A repositionable stand for CRT monitors or the like, comprises: (a) base support means (12); (b) extension means (96) for supportably transporting a CRT monitor platform (104) reciprocally toward and away from said base support means, said extension means having adjustment actuation handle means (106) at a remote end; (c) articulating arm means (48, 50) coupled to said base means and supportably elevating said tension means into alternative elevational positions; (d) said extension means and said articulating arm means being actuatable by said actuation handle means and remaining in constant static equilibrium in respective positions until displaced by a manual actuation force applied to said actuation handle means. <IMAGE>

Description

ADJUSTABLE CRT SUPPORT STANK BACKGROUND OF THE INVENTION Field of the Invention The subject invention relates to support stands for CRT monitors generally, and more specifically to support stands which function to three dimensionally adjust the position of a CRT monitor relative to the user of the computer work station.

The Prior Art Adjustable stands for CRT monitors are known in the industry and have been well accepted. Such stands are typically mounted at a rearward portion of a work surface such as a desk, and support the monitor component to a computer system. The stands are used not only to support the monitor, but also permit movement of the monitor from a storage position to an operational distance suitable to the the operator.

More complex adjustable stands offer adjustment capability in the vertical direction, and also provide means for adjusting the tilt angle of the CRT monitor. U.S. Patent 4691886 discloses an adjustable display stand which uses a gas charged spring to elevate the support stand, as well as a secondary spring for adjusting the tilt angle of a supported monitor. While this device works well, it has several inherent disadvantages. The device can operate to elevate and lower the CRT monitor in the vertical direction, but cannot function to bring the monitor toward and away from a user who is typically seated across the desk top surface from the monitor. Furthermore, the counterbalancing force generated by the spring which is used to elevate the support arm can only be used for one weight of monitor, and substituting a heaver monitor will cause an imbalance in the unit.Also, as the spring ages, its support force tends to decrease which can further create an imbalance and cause a gradual collapse of the unit.

A second type of existing support stand utilizes arm linkages which are pivotally coupled so as to move a CRT monitor horizontally and vertically in discrete increments relative to the user. U.S. Patent 4562987 discloses such a stand. The pivoting arms are connected to support collars which pivot about vertical posts. While this structure works well, it is limited in that the height adjustment occurs at discrete levels rather than being continuously variable. Also, the weight of the arms and the CRT must be lifted by the user for any vertical adjustment. Furthermore, there is no tilt mechanism which can serve to change the angular attitude of the CRT monitor. Finally, adjustment of this mechanism is cumbersome and requires several locks to be secured before the unit is in a stable and usable condition.

The shortcomings attendant to the aforementioned prior art support stands are overcome by the subject invention, which provides an adjustable stand for a CRT monitor capable of compensating for the specific weight of a range of commercially available monitors. The adjustable stand can slide reciprocally along its longitudinal axis toward and away from the user as it is simultaneously raised and lowered by the support arms. The subject adjustable stand accordingly can support a weight whose magnitude can vary from a 2.5 to 1 to as high as a 8 to 1 ratio, and allow the weight to be freely positioned within a spatial envelope defined by two toroidal segment surfaces and two horizontal planes.In other words, the CRT monitor can move in infinitely fine increments about a vertical axis (i.e. pivot); move toward and away from that vertical axis over its intended range of operation; and move up and down over its range of vertical motion. The counterbalancing spring is adjustable to the specific weight of the CRT monitor to be supported, is stepless, and provides an infinite number of settings over the range of operation. Once balanced against the spring, the weight stays balanced regardless of its position in the spatial envelope.

A swivel pedestal is mounted upon the top forward surface of the top beam, whereby the CRT monitor can further pivot about a secondary vertical axis and be angularly adjusted in a vertical direction to suit the visual line of the user.

Optimal reduction of reflected glare off the CRT screen is thereby achievable.

Accordingly, it is an objective of the present invention to provide an adjustable stand for CRT monitor which can support CRT monitors, each having a different weight.

A further objective is to provide an adjustable stand to support and maintain a CRT monitor weight within a spatial envelope defined by two toroidal segments surfaces and two horizontal planes.

Yet a further objective of the subject invention is to provide an adjustable stand having counterbalancing means which Is adjustable over a prescribed range to correlate with the weight of the load supported by the stand.

A further objective of the present invention is to provide an adjustable stand having counterbalancing means which is continuously readjustable in stepless gradation over a prescribed range to correlate with the weight of the load supported by the stand.

Still further, it is an objective of the subject invention to provide an adjustable stand having counterbalancing spring means and means for compensating for any diminution in spring force over time.

Yet a further objective is to provide an adjustable stand having means for counterbalancing a weight at any position within a three dimensional spatial envelope.

Another objective of the present invention is to provide an adjustable stand for a CRT monitor which is readily assembled and economically manufactured.

These and other objectives, which will be apparent to one skilled in the art, are achieved by a preferred embodiment which is described in detail below, and which is illustrated in the accompanying drawings.

Brief DescriDtion of the AccomPanvin Drawings Figure 1 is a perspective view showing the subject adjustable stand and its various directional modes of operation.

Figure 2 is a side elevation view in longitudinal section of the subject adjustable. stand taken along the line 2-2 of Figure 1.

Figure 3 is a top plan view, partially sectioned for illustration purposes, of the support stand taken along the line 3-3 of Figure 2.

Figure 4 is a front elevational view of the upper portion of the subject adjustable stand taken along the line 4-4 of Figure 2.

Figure 5 is a top cross-sectional view through the midsection of the subject adjustable stand taken along the line 5-5 of Figure 2.

Figure 6 is a top plan view of a base portion of the subject adjustable stand, broken away partially for illustration purposes, taken along the line 6-6 of Figure 2.

Figure 7 is a rearward elevational view of the base pedestal of the subject adjustable stand taken along the line 7-7 of Figure 2.

Figure 8 is a vertical longitudinal section view through the base of the subject adjustable stand, showing repositionment of the anchorage point of the support spring pursuant to the teaching of the subject invention.

Figure 9 is a perspective view of a separate bracket having camming surfaces which can be used alternatively in the practice of the subject invention.

Figures 1OA and 108 are vector diagrams showing force vectors of the support stand system supporting a weight i, with the articulating support arms in an elevated position, and a horizontal attitude, sequentially.

Figures llA and liB are vector diagrams showing force vectors of the subject support stand system supporting and counterbalancing an increased weight 2W in elevated and horizontal attitudes, sequentially.

Figures 12A and 12B are vector diagrams showing the force vectors of the subject support stand system supporting a still further increased weight 3W in elevated and horizontal attitudes, sequentially.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to Figure 1, the subject adjustable stand 2 is shown generally as supporting a computer CRT monitor 4.

Stand 2 is intended for mounting attachment to the top of a work surface, such as a desk, as shown generally at 6. Referring jointly to Figures 1 and 2, a protective pad 8 is positioned upon the top surface 6 adjacent to a rearward edge. A mounting bracket 10, of generally U-Shaped profile, is provided to clamp to a rearward edge of work surface 6 in a conventional manner.

Clamping means (not shown) is provided on the bottom of bracket 10 for securely affixIng bracket 10 to the work surface 6.

Clamping mechanisms of the type represented by bracket 10 are typically used in desk mounted accessories in the computer accessory industry.

Alternatively, the subject invention can be practiced by affixing bracket 10 tithe top surface 6 by means of screw fasteners, or against the back of a desk by a clamp, or to a vertical wall. The various alternative types of attachment techniques which can be used are depicted In a sales brochure entitled "CRT Valet", published by MicroComputer Accessories Inc., 5405 Jandy Place, P.O. Box 66911, Los Angeles, California 90066-0911, hereby incorporated by reference.

A base plate 12 is attached to the mounting bracket 10, by means of a centrally located pivot pin 14. Base plate 12 accordingly rotates 360' about a vertical axis represented by pivot pin 14. Pivot pin 14 proceeds downward through a base plate aperture 16 and through a mounting bracket aperture 18.

Extending along sides of the base plate 12 are side plates 20, 22 of generally truncated triangular profile. Bracket plates 20, 22 are parallel and spaced apart a distance representing the width of the base plate 12. Downturned ear portions 26, formed respectively from medial portions of the support bracket side plates 20, 22, extend horizontally and provide lateral support to the base plate assembly 12, 20, 22. It will be appreciated that the base plate 12 and ear portions 26 are attached to the top of the bracket member 10 by means of the pivot fastener 14.

Each of the support bracket sides 20, 22 are formed having an upturned arcuate camming slot 28, 30 therethrough respectively. Camming slots 28, 30 are defined by the following. Each of the arcuate camming slots extends diagonally from a top rearward portion of the side plates 20, 22 toward a lower front portion of the bracket plates, and each has a generally upwardly concave shape defined in part by an inwardly disposed arcuate camming surface 29.

With reference to Figures 6 and 7, a fixed cross pin 32 extends between the support bracket plates 20, 22 and has a central bore 34 extending therethrough. A camming pin 36 is further provided having ends which reside in the camming slots 28, 30, and which extend from a central post block 38. The post block portion 38 is provided with a central threaded throughbore 40.

A rotary adjustment screw, as shown at 42, extends downwardly through the cross pin throughbore 34 into the camming pin post block bore 40. A manual rotary knob 44 is affixed to the end of the adjustment screw 42. The adjustment screw 42 is further provided with an annular retention' collar 46 disposed adjacent to the rotary knob 44, and against the fixed pin 32.

Retention collar 46 prevents the screw from progressing downwardly as rotary knob 44 is turned. Accordingly, the threaded post block 38, upon rotation of the rotary screw 42 by way of the rotary knob 44, is moved downward or upward depending on the direction of rotation. The ends of the camming pin 36, which reside in slots 28, 30, are accordingly moved downward or upward within the camming slots and against camming surfaces 29.

As will be seen in Figures 1, 2, and 3, the subject adjustable stand is provided with an upper articulating support arm 48, and a lower secondary support arm 50. The support arm 48 is formed having opposing sides 52 connected by a top plate 54.

The sides 52 define a downwardly open channel 56 extending substantially the longitudinal length of arm 48.

Sides 52 are pivotally connected to a top portion of the support brackets 20, 22 by way of pin 53. A dependent attachment piece 55 projects downward from the top plate 54, about mid-length of the arm 48.

A top bracket 58 is pivotally connected to the upper portions of the support arm sides 52 at pivot pin connections 60. The top bracket 58 comprises bracket sides 62, 64 which are parallel spaced apart a distance generally corresponding with the spacing between upper support arm sides 52. The pivot pin 60 extends transversely between bracket sides 62, 64, as best seen in Figure 3. A centrally disposed cylindrical spacer sleeve 66 is positioned between the bracket sides 62, 64 and provides a longitudinal throughbore through which the pivot pin 60 extends.

A pair of rearwardly disposed cylindrical roller members 68 are attached to the ends of the pivot pin 60 for a purpose described below. Roller members 68 are cylindrically shaped and have an outer sheath preferably composed of rubber or plastic.

A compression spring 94 extends between the forward and rearwardly disposed posts 86, 82 respectively, and receives therethrough the threaded adjustment screw 92.

As shown in Figures 1 and 2, the subject adjustable stand is provided with an elongate top beam member 96. The beam member 96 is provided having a longitudinal, bottom opening, channel 98 defined by top wall 99, sidewall 100, forward end wall 101, opposite sidewall 102 (sectioned away), and rearward end wall 103. A horizontally disposed top plate member 104 is attached to the top beam member 96 at any one of several forward mounting positions provided there along, and a formed dependent bar handle 106 is provided which can be best viewed from Figure 1.Situated on top of the top wall 99 is a swivel/tilt support pedestal 108, of the general type available in the computer accessory industry. (For example, Microcomputer Accessories Inc., of 5405 Jandy Place, P.O. Box 56911, Los Angeles, California 90066-0911, manufactures such a device as Swivel Pedestal Stand Model 900.) The swivel pedestal 108 supports plate 104 and is adapted to tilt a CRT monitor positioned upon plate 104 approximately 12 upward and downward from the horizontal, and is further adapted to rotate 360v. Two central bolt/nut fasteners 110 extend downward through the pedestal stand 108, as shown in Figure 1, through appropriate apertures in conventional fashion to secure the stand to beam member top wall 99.

As shown in Figure 2, a gas charged support spring 112 is provided with the adjustable stand, of a general type commonly available in the industry. For example, (SUSPA) manufactures such a gas spring, as Model 16-4, which is suitable for the subject application. The gas spring includes a reciprocal piston rod 114, and a yoke mounting projection 116 at a lower end, as shown In Figure 8. The yoke 116 is provided with U-Shaped slots 118 in opposite dependent legs which fit over the ends of the camming pin 36 as shown in Figure 2. Thus, it will be appreciated that movement of camming pin 36 operates to move the anchorage point of the gas spring 112 forward and backward along the camming slot 28. The remote cylinder end of the piston 112 is attached to the dependent piece 55 of the upper articulating support arm 48 by a pivot pin 115.Accordingly, as articulating support arm 48 is raised or lowered, the spring will pivot at its lower end about camming pin 36, and at its upper end about the pivot attachment 115 to dependent flange 55. The gas spring can alternatively be reversed and positioned with the piston pivotally anchored to the camming pin 36 and its cylinder connected to the arm 48 if desired.

Figure 9 illustrates an alternative embodiment of the subject invention, which takes the camming slots 28 provided in the support brackets 20, 22, and incorporates such structure into an independent base bracket 120. Bracket 120 can be inserted between the support brackets 20, 22 upon base plate 12. As shown in Figure 9, the bracket 120 is provided with internal flanges 122 in opposing internal walls which are shaped to provide camming surfaces 124. Such surfaces 124 can operate in the identical manner as slots 28 in the preferred embodiment. Also shown in Figure 9, assembly apertures 126 are provided to secure the bracket 120 between the support plate bracket sides 20, 22 by the predescribed attachment fasteners.

Operation of the subject adjustable stand is described as follows. The stand is designed to counterbalance and support a weight whose magnitude can vary over at least a 2.5 to 1, to as high as a 8 to l ratio. Accordingly, the subject stand can accommodate a variety of available brands of CRT monitors for computer systems, which may vary one to another in weight from 15 pounds or less, to 75 pounds or more.

It will be appreciated from Figures 1 and 2 that a CRT monitor positioned on top of the support pedestal 108 can be tilted forward and backward, typically 12 from horizontal in either direction. Further, the monitor can be rotated 360'. It will also be appreciated that the articulating arms 48, 50 can be angularly adjusted by manual movement of the dependent bar handle 106. Movement of the articulating arms causes the gas spring piston 114 to stroke within gas spring housing 112.

As will be understood from Figure 2, the location of the pivot point for the gas spring 112 can be adjusted along the camming surface 29 by actuation of adJustment knob 44. Rotation of knob 44 causes adjustment screw 42 to drive post block 38 (Figure 7), thereby moving camming pin 36 along the camming surface 29. Movement of camming pin 36 will cause a corresponding movement in the yoke portion 116 of the gas spring 112. Positionment of the gas spring pivot point along camming surface 29 is initially selected to counterbalance for the specific weight of the monitor to be supported.

The rationale for moving the pivot axis of the gas spring 112 will be understood by sequential consideration of the force vector diagrams of Figures 10A, lOB, llA, llB, and 12A, 128.

In Figure lOA, the gravitational force of weight W is balanced by pneumatic spring force Sh (the subscript "h' designating the "high' condition of the arm and the subscript Wl the "low" position throughout the discussion), if their respective torque moments around link pivot P are approximately equal. (In practice, the difference must be less than frictional moments in the pivots and spring.) This condition is satisfied if the products ah'W and bheSh are equal. Moment arm ah = link length L sin B.

Fig. 108 shows that as weight W is lowered by changing angle ss to 90', ah also changes to L, and the spring moment arm bh changes to bl. Weight W and link length L do not change. Spring force is a function of spring length Ls, and it too changes.

Relating these changes, it must be observed that for balance to be maintained, the work absorbed by the spring, (LSh - LS1) (Sh + S1) / 2, must equal the potential energy lost by the weight, which equals W L cosS. (Equation Sol).

Figs. llA, llB show that if weight W is doubled, a new spring support point must be used along the compensating cam surface. As the spring force S does not change much, its moment arm b must be nearly doubled in the up position, but increased considerably less in the down position. As 2W is lowered, the same relationships must be true as for the single unit of weight, including equation tl.

Figs. llA and liB further illustrate the point by balancing 3W, or three times the original weight. While supporting a light weight, the spring is operating in a more extended (hence applying less force) mode overall, while for greater weights it is operating both with a greater working nht ig stroke and a greater force range as it is generally more compressed.

Accordingly, the subject stand can accommodate support of a variety of available brands of monitors, each of which may vary one to another in weight within the prescribed range of design.

It will be appreciated from Figures 1 and 3, that the articulating arms 48, 50 can be angularly adjusted by manual movement of the dependent bar handle 106. A CRT monitor positioned on top of the pedestal 108, once freely positioned, remains in that position. The monitor can be repositioned within a spatial envelope defined by two toroidal surfaces and two horizontal planes. In other words, the load can move any amount about a vertical axis completely around a pivot point (represented by the pivotally mounted base plate 24); can move any amount toward and away from the axis of rotation over a limited range of approximately 10 to 16 inches (by operation of the reciprocally moving top beam member 96); and move any amount up and down over a limited range of approximately 7 inches (by articulation of support arms 48, 50).

When the CRT monitor to be supported by the adjustable stand has been selected, the monitor is counterbalanced by adjustment of the pivot point for the gas spring 112. The point of counterbalance, defined by that spring anchorage point where the spring can support the weight of arms 48, 50, and the monitor carried thereby, can be identified by trial and error during initial adjustment. Once the counterbalancing of the gas spring pivot point has been set, the stand is permanently counterbalanced for that weight regardless of its location within the spatial envelope. Repositionment is accomplished by simple movement of handle 106, and is stepless (I.e. an infinite number of settings) over the entire range. Furthermore, the adjustable stand can be recounterbalanced when additional weight is added or weight is removed. Again, once rebalanced, the weight stays balanced regardless of its position in the spatial envelope. The pivotal attachment of the base support structure to the desk top provides a secondary rotational capability for the superstructure about a vertical axis, complementing the adjustment at the tiltable pedestal.

As will be appreciated by those skilled in the art, the subject adjustable stand provides distinctive advantages over the prior art which typically only offers counterbalancing as a predetermined weight is moved along a single toroidal surface.

Other mechanisms do not offer substantially infinite gradations of adjustment for the supported weight achieved in the subject stand.

Further, it is the nature of springs, especially the gas charged springs usually employed in such applications, to slowly lose some supporting force over a period of time, eventually becoming dlsfunctional. In order to compensate for the loss of force in the spring due to aging, the subject adjustable stand provides that the spring support point can be moved in order to counterbalance for the loss of spring force In the same manner as explained above for variation in the weight of the CRT monitor.

As explained above, the other degrees of freedom provided in positioning the weight in the subject adjustable stand operate independently of the counterbalancing spring mechanism. The parallel adjustment arms, coupled in essentially a parallelogram manner, permit the top beam member to horizontally carry the weight toward or away from the user. To maintain the horizontal motion of the arm despite possible sag and tilt at the mounting surfaces (table top, etc.), the adjustment screw 92 (Figure 3) is provided in the top bracket connected to the articulating arms.

This adjustment mechanism is illustrated in Figures 2, 3, 4 and 5. Figure 2 shows that the leveling pivot joining the top bracket to the lower link is free to slide in oblong slots 84 in the top bracket portion 78, while it pivots in round holes 93 in the upper arm sides 52. The oblong slots are angled in such a fashion that moving the leveling pivot along the slots raises or lowers the pair of rollers supporting the top beam member near the handle. Figures 3, 4 and 5 further illustrate the arrangement of the pin, leveling screw and spring. An access hole 128 in the lower arm 50 allows the user to make leveling adjustments with a screwdriver. The leveling spring operates to take transitory motion out of the mechanism, making it "former' in operation.

While Figures 6, 7, and 8 illustrate the preferred lower adjusting mechanism, with the compensating surface intergral to the bottom bracket, Figure 9 shows that, alternatively, the compensating camming surface may be formed into a separate part that is assembled into the lower mechanism.

Figure 1 shows the overall arrangement of the adjustable stand with the various directional modes of adjustment.

While the subject stand is illustrated in for use in conjunction with a CRT monitor, it should be appreciated that the nature of the supported load can vary. Hence, the applications to which the subject invention can be put are wide ranging and general.

While the above describes the preferred embodiment of the subject invention, the scope of the subject invention is not be to so restricted. Other embodiments, which utilize the teachings herein setforth, are intended to be within the scope and spirit of the subject invention.

Claims (9)

1. A repositionable stand for CRT monitors or the like, comprising: (a) base support means; (b) extension means for supportably transporting a CRT monitor platform reciprocally toward and away from said base support means, said extension means having adjustment actuation handle means at a remote end; (c) articulating arm means coupled to said base means and supportably elevating said extension means into alternative elevational positions; (d) said extension means and said articulating arm means being ana remaining in constant static equilibrium in respective positions until displaced by a manual actuation force applied to said actuation handle means.

2. A repositionable stand according to claim 1, further culDr sir.g counterbalancing means for counterbalancing said monitor with a counterbalancing force, whereby said monitor or the like corrirucusly reins in counterbalanced equilibrium throughout displacement of said extension means and said articulating arm means by said manual actuation force.

3. A repositionable stand according to Claim 2, further comprising compensation means for adjusting the effective direction of said counterbalancing force.

4. A repositionable stand according to Claim 3, said counterbalancing means comprising spring means having one end rotatably connected to said base means and an opposite end rotatably connected to said articulating arm means, said cacDer.saFion means including actuation means for moving said one end of said spring means relative to said base means.

5. A repositionabie stand according to any of claims 1 to 4, wherein said extension means being reciprocally movable along a longitudinal axis.

6. A repositionable stand according to Claim 5, said extension means comprising an elongate beam member slidably journalled to an upper end of said articulating arm means and supporting said CRT monitor at a forward end.

7. A repositionable stand according to Claim 6, said monitor is rotatable about a vertical axis extending through said beam member forward end.

8. A repositionable stand according to Claim 7, wherein said articulating arm means being rotatably coupled to said base means, whereby said monitor being further rotatable about a second vertical axis extending through said base means.

9. A repositionable stand for CRT monitors or the like, substantially as described herein with reference to and as illustrated in the accompanying drawings.