FIELD OF THE INVENTION
- BACKGROUND OF THE INVENTION
The present invention relates to a pivotal device for a monitor and includes a connection member fixed on the monitor and a link which is pivotably connected between the connection member and the base so that the monitor can be pivoted and secured at desired angles.
A conventional pivotal device for monitors is connected between a base and the monitor which can be pivoted about a bolt of the pivotal device and secured at a desired angle. However, the sizes of monitors are made much larger than before so that the weight of the monitors is difficult to be supported by the friction of the pivotal device. Therefore, the large size monitor can only be pivoted at limited angles which are not satisfied by the users.
FIG. 9 shows a conventional pivotal device for a monitor 90 and generally includes a connection member 91 connected to a rear side of the monitor 90 and a bolt 92 extends through the connection member 91 and is connected between two lugs 950 extending from a base 95. A plurality of washers 94 are mounted to the bolt 92 and two nuts 93 are connected to the two ends of the bolt 92 so that the rotation of the bolt 92 is limited by friction forces of the washers and the lugs 950. However, it is noted that the torque by the friction between the bolt 92 and the washers 94 is so small and equals to f×r, wherein f represents friction force and r represents radius of the bolt 92. The torque has to be large enough to support the downward torque of W×L, wherein W represents the weight of the monitor 90 and L represents the distance between the center of weight of the monitor 90 and the bolt 92. Obviously, the conventional pivotal device cannot support the monitor 90 beyond a certain angle.
- SUMMARY OF THE INVENTION
The present invention intends to provide a pivotal device for a monitor and the center of weight of the monitor is located in the area compassed by the link and the connection member of the pivotal device, so that the monitor can be well supported at desired angles.
The present invention relates to a pivotal device for monitors and the device comprises a connection member fixed to a rear side of the monitor and the connection member is pivotably connected on a base. A link has a first end pivotably connected to the connection member and a second end of the link is pivotably connected to two lugs on the base. A distance is defined between the connection member and the lugs. The link can be pivoted and moved axially relative to the lugs so as to support the monitor at desired angles.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
FIG. 1 shows the pivotal device of the present invention;
FIG. 2 is a side view to show a monitor is supported by the pivotal device;
FIG. 3 is a cross sectional view to show the connection between the adjustment bolt, the elastic assembly, the link and the first lugs of the pivotal device of the present invention;
FIG. 4 is an exploded view to show the pivotal device of the present invention;
FIG. 5 illustrates the analysis of forces of the support of the monitor by the pivotal device of the present invention;
FIG. 6 shows another embodiment of the link;
FIG. 7 is a cross sectional view to show yet another arrangement of the adjustment bolt, the elastic assembly, the link and the first lugs of the pivotal device of the present invention;
FIG. 8 shows that the elastic assembly includes two elastic tubes, and
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 9 shows a conventional pivotal device for supporting a monitor.
Referring to FIGS. 1 to 4, the pivotal device for monitors 10 of the present invention comprises a connection member 20 which is received in a recessed area 11 in a rear side of the monitor 10 and the connection member 20 includes two legs 21 which are pivotably connected to two lugs 41 on the base 40 by a bolt 23 which is connected with a nut.
A link 30 has a hole 31 defined in the first end thereof and the first end of the link 30 is pivotably connected to the two lugs 22 extending from the connection member 20 by another bolt 23 cooperated with a nut. A second end of the link 30 has an axial slot 32 define therethrough and the second end of the link 30 is pivotably connected to a lug 42 and a restriction lug 60 by an adjustment bolt 50 and a nut. The lug 42 is split from the bas 40 and the restriction lug 60 which is fixed on the base 40 by a bolt. A distance is defined between the connection member 20 and the lug 42 and the restriction lug 60. The adjustment bolt 50 extends through the slot 32 and the lug 42 and the restriction lug 60. An elastic assembly is sandwiched between the link 30 and the lug 42 and the restriction lug 60 so as to provide proper biasing force to prevent the adjustment bolt 50 from spinning and to generate friction force. The elastic assembly includes a plurality of flexible washers 70 and 80. The flexible washers 70 can be replaced with oil bearings or linings and the washers 80 can be bowl-shaped or flat washers so as to generate a force to prevent the adjustment bolt 50 from spinning.
The adjustment bolt 50 includes a polygonal head 51 and the restriction lug 60 includes a restriction arrangement which is a polygonal hole 61 with which the polygonal head 51 of the adjustment bolt 50 is engaged. By the engagement of the polygonal hole 61 and the polygonal head 51, the adjustment bolt 50 does not spin.
As shown in FIG. 5, the torque that the monitor 10 applies to the bolt 23 for connecting the two legs 21 and the lugs 41 is W×L, wherein W represents the weight of the monitor 10 and L represents the distance between the center of weight of the monitor 10 and the bolt 23 for connecting the two legs 21 and the lugs 41. The support force f(all) is composed of a first component force fh and a second component force fv. The fh is perpendicular to the connection line between the two bolts 23 of the lugs 22 and 41. The torque fh×l is applied toward the opposite direction of the torque W×L. It is noted that the arm of force “l” (between the bolts 23 of the lugs 22 and 41) is much larger than the radius of the bolt 92 as described in the conventional pivotal device, so that the torque that overcomes the torque due to the weight of the monitor 10 is larger than the conventional pivotal device. In other words, a less force of fh can obtain the same torque that the conventional pivotal device achieves.
FIG. 6 shows that the link 30 can be made to be a curve link and FIG. 7 shows that the link 30 is located at an outside of one of the two lugs 60 and the number of the flexible washers 70 and 80 is reduced to be one or two and the link 30 and one of the tow lugs 60 are located between two pairs of the flexible washers 70 and 80. As shown in FIG. 8, the elastic assembly may be two elastic tubes 81.
The pivotal device provides a large support area composed of the restriction lug 60, the lug 42 and the lugs 41 so that the center of weight of the monitor 10 falls in the area so as to be well supported. The arm of force “L” between the lugs 41 and the center of weight of the monitor 10 has a certain length so that the torque to prevent the monitor 10 from falling backward is sufficient. The link 30 can be easily adjusted and fixed in position by operation of the adjustment bolt 50 to support the inclination of the monitor 10.
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.