CA1283089C - Multi-position articulated arm lockable adjustable holder - Google Patents
Multi-position articulated arm lockable adjustable holderInfo
- Publication number
- CA1283089C CA1283089C CA000517368A CA517368A CA1283089C CA 1283089 C CA1283089 C CA 1283089C CA 000517368 A CA000517368 A CA 000517368A CA 517368 A CA517368 A CA 517368A CA 1283089 C CA1283089 C CA 1283089C
- Authority
- CA
- Canada
- Prior art keywords
- holder
- joint
- section
- brake shoe
- pivot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000006835 compression Effects 0.000 claims description 2
- 238000007906 compression Methods 0.000 claims description 2
- 230000000284 resting effect Effects 0.000 claims 2
- 230000002349 favourable effect Effects 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000007788 roughening Methods 0.000 description 1
Landscapes
- Pivots And Pivotal Connections (AREA)
Abstract
ABSTRACT
A holder for use with desks, drafting tables, CRT work stations, and the like, said holder consists of a multisection boom-type arm that is hinged to a base, the boom arm having at its free end a holder plate or the like. The sections of the boom arm are hinged to each other and the holder plate is hinged onto the boom arm. Manually adjustable, friction-type locking devices that control movement of the components are flexibly connected are associated with these pivoting joints. So that manipulation and adjustment is rendered far simpler, it is proposed to provide a handle that acts through an intermediate locking device on several of the pivot joints and is arranged close to the holder plate.
A holder for use with desks, drafting tables, CRT work stations, and the like, said holder consists of a multisection boom-type arm that is hinged to a base, the boom arm having at its free end a holder plate or the like. The sections of the boom arm are hinged to each other and the holder plate is hinged onto the boom arm. Manually adjustable, friction-type locking devices that control movement of the components are flexibly connected are associated with these pivoting joints. So that manipulation and adjustment is rendered far simpler, it is proposed to provide a handle that acts through an intermediate locking device on several of the pivot joints and is arranged close to the holder plate.
Description
~21330~39 The present invention relates to a holder for use in conjunction with desks, dra~ting tables, CRT work stations, and the like.
One such holder, known from United States 1,460,694 consists of a base and a multisection hoom-type arm hinged to the base and having at its free end a holder plate or the like. The sections of the boom arm are hinged to each other and the holder plate is hinged onto the boom arm. Manually adjustable, friction-type locking devices that control movement of the hinged components are associated with these pivoting joints, and in addition there is a handle that acts through an intermediate locking device on several of the pivot joints and is arranged close to the holder plate. The locking elements are arranged within the boom arm and a cable that crosses the centre pins of the joints is provided as the intermediate element.
Holders of this type make it possible to place an article in a workstation where it is in the most favourable position for the user. To this end, the base can be in the form of a heavy stand. Instead of incorporating a heavy stand, it is also pos~
sible to provide a clamp on the base to secure the holder to the edge of a table, for example; if this is done, it is possible to support the base on the clamp in such a manner as to permit it to - pivot about a vertical axis. The boom arm consists of at least two sections arranged in line behind each other so as to make it possible to adjust the height of the plate individually by pivoting the boom sections and permit adjustment of the reach of the boom ~283089 arm. To do this it is necessary to change the particular position of the boom arm; the locking devices arranged on the relevant joints are released by operating the handle and loosening the cable, whereupon the holder plate is put in the desired position and the lock is secured once again.
In keeping with the state of the art, however, it is only possible to achieve a force and friction connection by stretching the individual sections of cable located between the friction-type locking devices, which means that a considerable amount of force has to be applied to the handle in order to secure the locks, always providing that this is even possible. This fact is also taken into account in United States J,460,694 where each joint has its own manually operated clamping device. Proceeding from this state of the art, the present invention undertakes to create a holder where it is possible to release and secure the joints with a high level of reliability and by applying only a small force.
The invention provides a holder comprising a base hinged to one end of a multi-sectioned boom-type arm the opposite end of which carries a holder plate pivoted thereon, the sections of the boom arm being pivo-ted to each other;
manually adjustable, friction-type locking devices that control movement of the components that are pivotally connected being provided at the pivot joints;
a handle that acts through an intermediate locking element on several of the pivot joints being arranged close to said holder plate;
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the intermediate locking element and the locking devices being arranged within the boom arm; and a cable that crosses the axes of the pivot joints constituting said intermediate element, wherein:
the pivot joints have, parallel pivot pins that are oriented transversely to the length of the boom arm;
each locking device is configured as an internal-expanding brake having a brake shoe coaxial to the associated pivot pins and carried in a :Eirst portion o.E a pivot joint, each said brake shoe being annular in form and almost circular, having two confronting ends that are separated by a gap, an expander unit that engages in said gap between the confronting ends of the brake shoe being held on the other, second, portion of the pivot joint and being operable by means of said handle, with the second portion being connected so as to rotate in response to movement of said handle.
the expander being operable to press the brake shoe against an adjacent cylindrical surface on the second joint portion so as to provide a friction lock, the expander unit being supported to rotate about a pin that is parallel to the joint axis and having a minor dimension approximating the distance between the brake shoe ends when released, and a major dimension that is greater than the distance between the ends of the brake shoe so that said shoe is pressed against said cylindrical surface;
a lever extending from the expander unit being connected to a spring element that urges the lever to a locked position, and also being connected to a section of said cable, wherein all the ,~
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cable sections are configured as intermediate elements and are connected to be operated in unison by means of said handle to release the associated brake shoes.
By this means it is possible to release and to secure all the locking devices by using just one handle; furthermore, ~hen this is done, only the force of the springs that act on the 3a B
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~,z83~8~ , expander units has to be overcome. Moreover, when in the released position each brake shoe is released completely from the adjacent cylindrical surface (and can be rotated relative to this), and because of its inherent springiness rests against the relatively non-rotatable surface, and this reduces the manipulation force that is required.
It is possible to achieve a form-locking fit of the brake shoe with the associated cylindrical by roughening, milling or serrating the inner side of the contacting surfaces, so that unintentional movement that results from a lack of friction can be precluded.
In order to be able to adjust the holder plate to the most favourable position, even if the base is in an unsatisfactory place on the working surface, it is advantageous if the joint that connects the holder plate and the boom arm is in the form of a universal joint, and that at least one dedicated locking device is associated with the universal joint, particularly one in the form of a rotatably mounted tensioning eccentric, in order to make it possible to adjust the holder plate independently of the boom arm.
An embodiment of the present invention is described in greater detail below on the basis of the drawings appended hereto, wherein:-Figure 1 is a foreshortened and partially sectioned elevation view of a holder;
Figure 2 is a sectional view tahen on the line II-II
1~33~39 in Figure l;
Figure 3 shows a portion of the holder with a lock in the locked or secured position;
Figure 4 is like Figure 3, but shows the lock-released;
Figure 5 shows individual components of the holder as seen in the direction indicated by the arrow V in Figure l; and Figure 6 is a cross-section on the line VI-VI in Figure 5.
Essentially, holder consists of a base 1, a multisection boom-type arm 2 and a holder plate 3 that is installed on the free end of the arm 2. The base 1 is mounted on a stand (not shown) or on a clamp (not shown) so as to be able to rotate about a ver-tical axis. The base 1 can also be fitted with a device that makes it possible to attach the holder to a vertical wall.
The boom arm 2 that is hinged to the base 1 consists of two oblong arm sections 5 and 6 thatare hingedly connected to each other and the holder plate 3 is attached to the free end of the boom 2 by means of a universal joint 7, having swivel pins oriented so as to be at right-angles to each other.
The two other joints, namely, the joint 8 that connects the boom section 5 to the boom section 6 are single-pin pivot joints having horizontal pivot pins that are parallel to each other.
Each of the boom sections 5 and 6 is assembled from essentially trough-shaped elements so that toyether form a box section profile. At the base section 1 and at the other end of the boom section 5 two flat surfaces 10 are formed in the walls ' , ' ' oppositely facing and are, in addition, at right-angles to the pivot axis and receive the inner sides of a forked end of the boom sections 5 or 6. Pivot shoulders 11 protrude inwards from the inner sides of the aforementioned end sections and these face each other in pairs and enga~e in a passage 12 in the base 1 or the boom section 5 so as to be able to rotate. In addition, there are blind holes 13 in the two pivot shoulders 11 and a bolt 14 is inserted in these.
In each joint 8 and 9 there is a locking device that can be operated through the cables 15 and 16 by means of a handle 17 (Figures 5 and 6) arranged on the holder plate 3. The locking devices are in the form of internal expanding brakes. In each sur face 10 there is an annular groove 18 of greater diameter than the through hole 12 and coaxial with this. In each annular groove 18 is inserted an almost circular, brake shoe 19 that can be spread apart. Each brake shoe 19 is enclosed by an annular spring 20 and this spring exerts a force that is directed inwards with the result-as can be seen from Figure 4--that when the annular spring 20 is not loaded the brake shoe 19 is at a distance from the radially outermost side of the annular groove 18 and, in contast thereto, the brake shoe rests against the radially inner side of the groove 18.
Between the separated ends of each brake shoe 19 there is an oval expander unit 21. The expander units 21 are arranged within the boom sections 5 or 6 so as to be able to rotate about the pins that are parallel to the axis of the joint; the oval .
~2~330~9 profile expanders 21 are integrally moulded with cylindrical pivot pins 22. The minor width of each of the expanders 21 is smaller than the smallest distance between the two opposing ends of each brake shoe 19, whereas the major width of the expander is greater than the maximum distance that is possible between the opposing ends of the shoe 19, so that when the expander 21 is rotated the outer sides of the brake shoes 19 are pressed against the outer sides of the annular grooves 18 so as to form a friction lock and thus lock up the joint.
It is preferred that the frictional surfaces have ser-rations that engage in each other in order to provide a form fit when in the locked position and thereby create a quasi-rigid connection, this being out of engagement when in the released posi-tion as shown in Figure 4. A lever 23 projects from each expander unit 21, and these levers are rigidly connected in pairs by means of a stud 24 that is parallel to the axis of rotation of the expander 21.
The expander units 21 of each joint 8 and 9 are rotated into the locked position (Figure 3) by means of coil springs 25 ~:
arranged under compression within the boom sections 5 or 6. Each of the coil springs 25 is arranged on a two-part guide rod, the sections 26 and 27 of which telescope within one another. At both ends of the sections 26 and 27 there are shoulders against which the ends of the coil springs seat. At the free end of the rod section 26 there is a groove 28 that is arranged at right angles to the longitudinal extent of the rod section, and the stud 24 .
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engages in this in such a manner as to be able to rotate. The free end of the rod section 27 is configured as a ball head 29 that rests against a stop 30 having a ball-joint type depression that matches the ball head 29.
An end section of a cable 15, 16 is attached to each stud 24 and in the area of the studs 24 the cable sections 15 or 16 are guided so that the levers 23 and thus the expander units 21 can be rotated into the position shown in Figure 4 by tension applied through the cable sections 15 or 16. When released, the coil springs 25 cause the brake shoes 19 to spread apart and thus bring about a friction locking or, by meshing, form locking posi~
tioning of the brake shoes against the outer edges of the annular groove (Figure 3).
In the area of the joints 7, 8, and 9 the cable sections 15 and 16 are guided so as to cross over the centre axes of the joints. Suitable cable guides are fitted inside the joint pins for this purpose.
A shaft 31 rotatably supported at the rear of the holder plate 3 passes through and is secured rigidly to the handle 17.
A cam section 32 is fixed to the shaft 31 opposite the universal joint 7 and the end sections of the cable sections 15 and 16 are secured to the circumference of this cam segment 32 so that when ; the shaft 31 is rotated the cable end sections are as it were wound onto or off the cam segment 32. To ensure that the cable ~ sections 15 and 16 wind smoothly onto the cam section, they are ; guided to run at right-angles to the shaft 31. In order that t33~39 the cable sections 15 and 16 can be operated with equal ease by both left- and right-handed users, the shaft 31 extends over almost the whole width of the holder plate 3, and a handle 17 is attached to each end.
In addition to the foregoing, a locking device in the form of a tension eccentric 33 and acts on the universal joint 7, is also provided in the boom section 6.
It is also possible to have the outsides of the brake shoes provided with a friction coating. In the locking devices associated with the joints 8 and 9, the requirement must also be satisfied that when the locking devices are in the released posi-tion the lever 23 and the guide rods 26 and 27 do not rotate past the dead point, i.e. over centre, in order that the coil springs 25 can rotate the lever 23 back into the locked position. As can be seen from ~igure 4, in order to fulfill this requirement the movement of the lever 23 is restricted in that before it reaches the dead position, i.e., before the lever 23 and the guide rods 26 `~
and 27 all line up so as to form a straight line, the lever 23 abuts against the boom sections 5 or 6, respectively.
One such holder, known from United States 1,460,694 consists of a base and a multisection hoom-type arm hinged to the base and having at its free end a holder plate or the like. The sections of the boom arm are hinged to each other and the holder plate is hinged onto the boom arm. Manually adjustable, friction-type locking devices that control movement of the hinged components are associated with these pivoting joints, and in addition there is a handle that acts through an intermediate locking device on several of the pivot joints and is arranged close to the holder plate. The locking elements are arranged within the boom arm and a cable that crosses the centre pins of the joints is provided as the intermediate element.
Holders of this type make it possible to place an article in a workstation where it is in the most favourable position for the user. To this end, the base can be in the form of a heavy stand. Instead of incorporating a heavy stand, it is also pos~
sible to provide a clamp on the base to secure the holder to the edge of a table, for example; if this is done, it is possible to support the base on the clamp in such a manner as to permit it to - pivot about a vertical axis. The boom arm consists of at least two sections arranged in line behind each other so as to make it possible to adjust the height of the plate individually by pivoting the boom sections and permit adjustment of the reach of the boom ~283089 arm. To do this it is necessary to change the particular position of the boom arm; the locking devices arranged on the relevant joints are released by operating the handle and loosening the cable, whereupon the holder plate is put in the desired position and the lock is secured once again.
In keeping with the state of the art, however, it is only possible to achieve a force and friction connection by stretching the individual sections of cable located between the friction-type locking devices, which means that a considerable amount of force has to be applied to the handle in order to secure the locks, always providing that this is even possible. This fact is also taken into account in United States J,460,694 where each joint has its own manually operated clamping device. Proceeding from this state of the art, the present invention undertakes to create a holder where it is possible to release and secure the joints with a high level of reliability and by applying only a small force.
The invention provides a holder comprising a base hinged to one end of a multi-sectioned boom-type arm the opposite end of which carries a holder plate pivoted thereon, the sections of the boom arm being pivo-ted to each other;
manually adjustable, friction-type locking devices that control movement of the components that are pivotally connected being provided at the pivot joints;
a handle that acts through an intermediate locking element on several of the pivot joints being arranged close to said holder plate;
.. .
'' ' ~ : ' ' ' .
~2~30~
the intermediate locking element and the locking devices being arranged within the boom arm; and a cable that crosses the axes of the pivot joints constituting said intermediate element, wherein:
the pivot joints have, parallel pivot pins that are oriented transversely to the length of the boom arm;
each locking device is configured as an internal-expanding brake having a brake shoe coaxial to the associated pivot pins and carried in a :Eirst portion o.E a pivot joint, each said brake shoe being annular in form and almost circular, having two confronting ends that are separated by a gap, an expander unit that engages in said gap between the confronting ends of the brake shoe being held on the other, second, portion of the pivot joint and being operable by means of said handle, with the second portion being connected so as to rotate in response to movement of said handle.
the expander being operable to press the brake shoe against an adjacent cylindrical surface on the second joint portion so as to provide a friction lock, the expander unit being supported to rotate about a pin that is parallel to the joint axis and having a minor dimension approximating the distance between the brake shoe ends when released, and a major dimension that is greater than the distance between the ends of the brake shoe so that said shoe is pressed against said cylindrical surface;
a lever extending from the expander unit being connected to a spring element that urges the lever to a locked position, and also being connected to a section of said cable, wherein all the ,~
: 3 12~33~)8~
cable sections are configured as intermediate elements and are connected to be operated in unison by means of said handle to release the associated brake shoes.
By this means it is possible to release and to secure all the locking devices by using just one handle; furthermore, ~hen this is done, only the force of the springs that act on the 3a B
, . .
" - ~
~,z83~8~ , expander units has to be overcome. Moreover, when in the released position each brake shoe is released completely from the adjacent cylindrical surface (and can be rotated relative to this), and because of its inherent springiness rests against the relatively non-rotatable surface, and this reduces the manipulation force that is required.
It is possible to achieve a form-locking fit of the brake shoe with the associated cylindrical by roughening, milling or serrating the inner side of the contacting surfaces, so that unintentional movement that results from a lack of friction can be precluded.
In order to be able to adjust the holder plate to the most favourable position, even if the base is in an unsatisfactory place on the working surface, it is advantageous if the joint that connects the holder plate and the boom arm is in the form of a universal joint, and that at least one dedicated locking device is associated with the universal joint, particularly one in the form of a rotatably mounted tensioning eccentric, in order to make it possible to adjust the holder plate independently of the boom arm.
An embodiment of the present invention is described in greater detail below on the basis of the drawings appended hereto, wherein:-Figure 1 is a foreshortened and partially sectioned elevation view of a holder;
Figure 2 is a sectional view tahen on the line II-II
1~33~39 in Figure l;
Figure 3 shows a portion of the holder with a lock in the locked or secured position;
Figure 4 is like Figure 3, but shows the lock-released;
Figure 5 shows individual components of the holder as seen in the direction indicated by the arrow V in Figure l; and Figure 6 is a cross-section on the line VI-VI in Figure 5.
Essentially, holder consists of a base 1, a multisection boom-type arm 2 and a holder plate 3 that is installed on the free end of the arm 2. The base 1 is mounted on a stand (not shown) or on a clamp (not shown) so as to be able to rotate about a ver-tical axis. The base 1 can also be fitted with a device that makes it possible to attach the holder to a vertical wall.
The boom arm 2 that is hinged to the base 1 consists of two oblong arm sections 5 and 6 thatare hingedly connected to each other and the holder plate 3 is attached to the free end of the boom 2 by means of a universal joint 7, having swivel pins oriented so as to be at right-angles to each other.
The two other joints, namely, the joint 8 that connects the boom section 5 to the boom section 6 are single-pin pivot joints having horizontal pivot pins that are parallel to each other.
Each of the boom sections 5 and 6 is assembled from essentially trough-shaped elements so that toyether form a box section profile. At the base section 1 and at the other end of the boom section 5 two flat surfaces 10 are formed in the walls ' , ' ' oppositely facing and are, in addition, at right-angles to the pivot axis and receive the inner sides of a forked end of the boom sections 5 or 6. Pivot shoulders 11 protrude inwards from the inner sides of the aforementioned end sections and these face each other in pairs and enga~e in a passage 12 in the base 1 or the boom section 5 so as to be able to rotate. In addition, there are blind holes 13 in the two pivot shoulders 11 and a bolt 14 is inserted in these.
In each joint 8 and 9 there is a locking device that can be operated through the cables 15 and 16 by means of a handle 17 (Figures 5 and 6) arranged on the holder plate 3. The locking devices are in the form of internal expanding brakes. In each sur face 10 there is an annular groove 18 of greater diameter than the through hole 12 and coaxial with this. In each annular groove 18 is inserted an almost circular, brake shoe 19 that can be spread apart. Each brake shoe 19 is enclosed by an annular spring 20 and this spring exerts a force that is directed inwards with the result-as can be seen from Figure 4--that when the annular spring 20 is not loaded the brake shoe 19 is at a distance from the radially outermost side of the annular groove 18 and, in contast thereto, the brake shoe rests against the radially inner side of the groove 18.
Between the separated ends of each brake shoe 19 there is an oval expander unit 21. The expander units 21 are arranged within the boom sections 5 or 6 so as to be able to rotate about the pins that are parallel to the axis of the joint; the oval .
~2~330~9 profile expanders 21 are integrally moulded with cylindrical pivot pins 22. The minor width of each of the expanders 21 is smaller than the smallest distance between the two opposing ends of each brake shoe 19, whereas the major width of the expander is greater than the maximum distance that is possible between the opposing ends of the shoe 19, so that when the expander 21 is rotated the outer sides of the brake shoes 19 are pressed against the outer sides of the annular grooves 18 so as to form a friction lock and thus lock up the joint.
It is preferred that the frictional surfaces have ser-rations that engage in each other in order to provide a form fit when in the locked position and thereby create a quasi-rigid connection, this being out of engagement when in the released posi-tion as shown in Figure 4. A lever 23 projects from each expander unit 21, and these levers are rigidly connected in pairs by means of a stud 24 that is parallel to the axis of rotation of the expander 21.
The expander units 21 of each joint 8 and 9 are rotated into the locked position (Figure 3) by means of coil springs 25 ~:
arranged under compression within the boom sections 5 or 6. Each of the coil springs 25 is arranged on a two-part guide rod, the sections 26 and 27 of which telescope within one another. At both ends of the sections 26 and 27 there are shoulders against which the ends of the coil springs seat. At the free end of the rod section 26 there is a groove 28 that is arranged at right angles to the longitudinal extent of the rod section, and the stud 24 .
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engages in this in such a manner as to be able to rotate. The free end of the rod section 27 is configured as a ball head 29 that rests against a stop 30 having a ball-joint type depression that matches the ball head 29.
An end section of a cable 15, 16 is attached to each stud 24 and in the area of the studs 24 the cable sections 15 or 16 are guided so that the levers 23 and thus the expander units 21 can be rotated into the position shown in Figure 4 by tension applied through the cable sections 15 or 16. When released, the coil springs 25 cause the brake shoes 19 to spread apart and thus bring about a friction locking or, by meshing, form locking posi~
tioning of the brake shoes against the outer edges of the annular groove (Figure 3).
In the area of the joints 7, 8, and 9 the cable sections 15 and 16 are guided so as to cross over the centre axes of the joints. Suitable cable guides are fitted inside the joint pins for this purpose.
A shaft 31 rotatably supported at the rear of the holder plate 3 passes through and is secured rigidly to the handle 17.
A cam section 32 is fixed to the shaft 31 opposite the universal joint 7 and the end sections of the cable sections 15 and 16 are secured to the circumference of this cam segment 32 so that when ; the shaft 31 is rotated the cable end sections are as it were wound onto or off the cam segment 32. To ensure that the cable ~ sections 15 and 16 wind smoothly onto the cam section, they are ; guided to run at right-angles to the shaft 31. In order that t33~39 the cable sections 15 and 16 can be operated with equal ease by both left- and right-handed users, the shaft 31 extends over almost the whole width of the holder plate 3, and a handle 17 is attached to each end.
In addition to the foregoing, a locking device in the form of a tension eccentric 33 and acts on the universal joint 7, is also provided in the boom section 6.
It is also possible to have the outsides of the brake shoes provided with a friction coating. In the locking devices associated with the joints 8 and 9, the requirement must also be satisfied that when the locking devices are in the released posi-tion the lever 23 and the guide rods 26 and 27 do not rotate past the dead point, i.e. over centre, in order that the coil springs 25 can rotate the lever 23 back into the locked position. As can be seen from ~igure 4, in order to fulfill this requirement the movement of the lever 23 is restricted in that before it reaches the dead position, i.e., before the lever 23 and the guide rods 26 `~
and 27 all line up so as to form a straight line, the lever 23 abuts against the boom sections 5 or 6, respectively.
Claims (14)
1. A holder comprising a base hinged to one end of a multi-sectioned boom-type arm the opposite end of which carries a holder plate pivoted thereon, the sections of the boom arm being pivoted to each other;
manually adjustable, friction-type locking devices that control movement of the components that are pivotally connected being provided at the pivot joints;
a handle that acts through an intermediate locking element on several of the pivot joints being arranged close to said holder plate;
the intermediate locking element and the locking devices being arranged within the boom arm; and a cable that crosses the axes of the pivot joints constituting said intermediate element, wherein:
the pivot joints have, parallel pivot pins that are oriented transversely to the length of the boom arm;
each locking device is configured as an internal-expanding brake having a brake shoe coaxial to the associated pivot pins and carried in a first portion of a pivot joint, each said brake shoe being annular in form and almost circular, having two confronting ends that are separated by a gap, an expander unit that engages in said gap between the confronting ends of the brake shoe being held on the other, second, portion of the pivot joint and being operable by means of said handle, with the second portion being connected so as to rotate in response to movement of said handle, the expander being operable to press the brake shoe against an adjacent cylindrical surface on the second joint portion so as to provide a friction lock, the expander unit being supported to rotate about a pin that is parallel to the joint axis and having a minor dimension approximating the distance between the brake shoe ends when released, and a major dimension that is greater than the distance between the ends of the brake shoe so that said shoe is pressed against said cylindrical surface;
a lever extending from the expander unit being connected to a spring element that urges the lever to a locked position, and also being connected to a section of said cable, wherein all the cable sections are configured as intermediate elements and are connected to be operated in unison by means of said handle to release the associated brake shoes.
manually adjustable, friction-type locking devices that control movement of the components that are pivotally connected being provided at the pivot joints;
a handle that acts through an intermediate locking element on several of the pivot joints being arranged close to said holder plate;
the intermediate locking element and the locking devices being arranged within the boom arm; and a cable that crosses the axes of the pivot joints constituting said intermediate element, wherein:
the pivot joints have, parallel pivot pins that are oriented transversely to the length of the boom arm;
each locking device is configured as an internal-expanding brake having a brake shoe coaxial to the associated pivot pins and carried in a first portion of a pivot joint, each said brake shoe being annular in form and almost circular, having two confronting ends that are separated by a gap, an expander unit that engages in said gap between the confronting ends of the brake shoe being held on the other, second, portion of the pivot joint and being operable by means of said handle, with the second portion being connected so as to rotate in response to movement of said handle, the expander being operable to press the brake shoe against an adjacent cylindrical surface on the second joint portion so as to provide a friction lock, the expander unit being supported to rotate about a pin that is parallel to the joint axis and having a minor dimension approximating the distance between the brake shoe ends when released, and a major dimension that is greater than the distance between the ends of the brake shoe so that said shoe is pressed against said cylindrical surface;
a lever extending from the expander unit being connected to a spring element that urges the lever to a locked position, and also being connected to a section of said cable, wherein all the cable sections are configured as intermediate elements and are connected to be operated in unison by means of said handle to release the associated brake shoes.
2. A holder as in claim 1, wherein said adjacent cylindrical surface, and the surface of the brake shoe that is in contact with it when in the locked position are of roughened configuration.
3. A holder as in claim 2, wherein said surfaces of roughened configuration are serrated.
4. A holder as in claim 1, wherein the spring elements are coil springs installed under compression said coil springs each resting against the lever of the expander unit and against a stop of the second boom section.
5. A holder as in claim 4, wherein the coil spring is installed around a two-part guide rod, having sections which telescope into one another, and one section of which engages at its free end with the lever of the expander unit and the other section being flexibly connected with a stop on the second section, the coil spring resting at one end on one section and at the other end on the other section of the rod.
6. A holder as in claim 5, wherein one rod section has at its free end a groove that is oriented transversely to the longitudinal extent of the rod, in which groove a stud attached to the end of the expander unit lever oriented in the same direction as the groove engages, said stud being supported so as to be able to rotate about its longitudinal axis.
7. A holder as in claim 5, wherein said other rod section has a ball head at its free end, and in that in the stop of the second joint section there is a ball joint socket that works in conjunction with the ball head.
8. A holder as in claim 1 wherein in each instance the first element of a joint has parallel surfaces on two opposing sides in which in each instance there is an annular groove that is coaxial with the joint pin and in which is inserted a brake shoe, in the first joint element there is a continuous bore of smaller diameter than and coaxial with the annular groove; the second joint element being made up of two essentially trough-shaped profile rods that together make up a box-section profile, each rod having a pivot shoulder that protrudes transversely, these shoulders, being oriented towards each other, and being rotatably received in the continuous bore of the first joint element; an expander unit being associated with each brake shoe, the levers of said expander units being connected to each other and oriented in the same direction and connected to a stud that is transverse to the shoulders; a common spring element and a common cable acting on the studs of both expander units.
9. A holder as in claim 8, characterized in that coaxial bores are arranged in the pivot shoulders of both boom arm profile rods, a bolt being inserted in these bores.
10. A holder according to claim 1 wherein the joint that connects the holder plate with the boom arm is configured as a universal joint, at least one dedicated locking device being associated with the universal joint.
11. A holder as in claim 1, wherein said handle extends radially from a shaft that is supported behind the holder plate such that it can rotate, the shaft being transverse to the cable that passes through the universal joint, said shaft bearing a disc segment, said cable, which is under tension, being secured to the circumference of this disc segment.
12. A holder according to claim 4, wherein the shaft extends over almost the complete width of the holder plate, the disc segment being arranged opposite the universal joint and both end sections of the shaft being fitted with a handle.
13. A holder as in claim 5 or 6 wherein the movement of
14 the guide rods that bear the coil springs and of the lever is so restricted that the angle formed by the lever and the guide rods that support the coil spring is always less than 180°.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19843437300 DE3437300A1 (en) | 1984-10-11 | 1984-10-11 | CONCEPT HOLDER FOR USE IN WRITING, DRAWING, SCREEN WORKPLACES AND THE LIKE |
| EP85113678.8 | 1985-10-28 | ||
| EP85113678A EP0220334B1 (en) | 1984-10-11 | 1985-10-28 | Draft support for use at writing, drawing, video display spots and the like |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1283089C true CA1283089C (en) | 1991-04-16 |
Family
ID=25825547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000517368A Expired - Lifetime CA1283089C (en) | 1984-10-11 | 1986-09-03 | Multi-position articulated arm lockable adjustable holder |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1283089C (en) |
-
1986
- 1986-09-03 CA CA000517368A patent/CA1283089C/en not_active Expired - Lifetime
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |