FR3042434A3 - ARTICULATED ARM WITH WEIGHT COMPENSATION - Google Patents

Abstract

An articulated weight canceling support arm includes a securing portion 2 and a supporting portion 3 which is adapted to support a load C and is movable relative to the securing portion to permit movement of the load. relative to the fixing part. The two parts are interconnected by two elongate connecting elements 11 and 12 to form an articulated parallelogram structure which, with the variation of its own configuration, makes it possible to vary the height position of the support part 3 with respect to the fixing part 2. The two elongate connecting elements are connected to each other by a gas device with differentiated thrust constituted by: a gas spring 20 installed between the two elongated connecting elements in such a way that a lowering of the part support causes compression of the gas spring; and a preloaded mechanical spring 30 which acts on only one side of the piston 22 of the gas spring to exert a friction which opposes only the compression of the gas spring itself. The gas spring is installed between the two connecting elements to exert its extension thrust, opposing the mass force of the arm 1 and the associated load C, and is dimensioned in such a way that its nominal thrust, added to the pre-load of the mechanical spring, maintain the arm in static equilibrium with the associated load, of predetermined weight, in the absence of external thrusts.

Description

FIELD OF APPLICATION [001] The present invention relates to an articulated support arm weight canceller. In particular, the articulated support arm according to the invention is used to vary the height position of objects associated with it, avoiding that the weight of objects is the responsibility of the user. This arm can be used, in particular, to support and move objects or devices of predefined and constant weight, such as control panels, displays, monitors, tools. State of the art [002] Weight-canceling support arms for moving control panels are known.

[003] In systems of this type, the articulated arm supports a load by maintaining it in equilibrium in any position within a predetermined range of applicable positions and loads. This equilibrium situation is achieved by the combined action of two gas springs which are housed in the body of the arm and act on a part of the arm itself structured articulated quadrilateral. A spring is of the traditional type and a spring is of the control type, with a needle actuating head. The traditional gas spring works in thrust and tends to always move the load upwards; the needle-type gas spring, on the other hand, acts as a blockage of the traditional gas spring, thus causing the locking of the support arm. The deactivation of the needle spring is performed manually by means of a drive train which connects a control button (installed on the control panel supported by the arm) to the actuating head of the spring. Generally, the driveline consists of a Bowden cable that leaves the control panel and reaches the spring through the mechanical arm. The two gas springs are dimensioned in such a way that the thrust provided by the needle spring is greater than that provided by the traditional gas spring, so that the needle spring is able to lock the traditional gas spring, maintaining the arm stuck in the current position.

[004] Functionally, if the operator needs to move the control panel in height, he presses the button which, by means of the Bowden cable, causes the deactivation by the needle spring. The traditional gas spring, once the needle spring is off, still tends to lift (with minimal force) the load applied to the arm until the button is released. In this way, the weight of the load applied to the arm never rests on the operator. To lift the table, the operator must only wait until the gas spring brings the table up to the desired height, possibly accompanying and guiding its lifting; to lower the table, however, the operator must apply a minimal force down to overcome the residual thrust of the gas spring and release the button once the table is in the desired position, lower than that of departure. Once the button is released, the gas springs lock up thus behaving statically.

[005] The support arms according to the known technique, although allowing the movement and positioning of a load with ease, however, have a series of limits and disadvantages.

[006] First, these known type of arms are complex to achieve from the mechanical point of view because of the many components used. It is indeed necessary to provide two types of springs and a mechanical control element. The presence of the Bowden cable is also a complication both from the point of view of production and from the point of view of maintenance. The need to provide a kinematic control system introduces mechanical complexities that are detrimental to the reliability of the system.

[007] Secondly, the use of these systems is actually not practical for operators in that they require that the control button is continuously depressed to allow free movement of the arm. PRESENTATION OF THE INVENTION [008] Therefore, the object of the present invention is to eliminate the disadvantages of the known technique mentioned above, by providing an articulated arm of a weight-canceling support which can be used by an operator. in a simpler and immediate way without the need to act on mechanical controls.

[009] Another object of the present invention is to provide an articulated support arm weight canceller that is more reliable from the mechanical point of view.

Another object of the present invention is to provide an articulated support arm weight canceller that requires less maintenance.

Another object of the present invention is to provide an articulated support arm weight canceller that is easy and economical. Brief Description of the Drawings [0012] The technical features of the invention, in accordance with the foregoing objects, are clearly identifiable according to the content of the appended claims and its advantages will become more apparent in the following detailed description with reference to the drawings. appended which represent one or more embodiments purely illustrative and non-limiting, in which: - Figures 1 and 2 show two perspective views of an articulated arm according to a preferred embodiment of the invention, illustrated with a table associated control and in different positions, to show the different movements allowed for the positioning of the table; - Figure 3 shows a partially transparent side view of the arm according to the invention shown in Figures 1 and 2; FIG. 4 represents an orthogonal view from above of the arm according to the invention; - Figures 5A, 5B and 5C show the arm of Figure 3 in three different positions; - Figure 6 shows a detailed sectional view of a gas spring with differentiated thrust which is equipped with the arm according to the invention; Figure 7A shows the gas spring of Figure 6 during the extension phase; - Figure 7B shows the gas spring of Figure 6 during the compression phase.

DETAILED DESCRIPTION [0013] With reference to the accompanying drawings, an articulated weight-reducing support arm according to the invention has been indicated as a whole by 1.

Here and in the following description and claims, reference will be made to the articulated support arm weight canceller 1 in use condition. It should therefore be considered in this sense any references to a lower or upper position, vertical or horizontal.

According to a general embodiment of the invention, the articulated support arm weight canceller 1 comprises: - a fixing portion 2 intended to be associated with an external fixation structure to the arm 1 itself; and a support part 3 which is intended to support a load C and is movable with respect to the fixing part 2 to allow the displacement of the load C with respect to the fixing part 2.

The load C can be any object or device of predefined weight and constant, such as a control panel, a display, a monitor, a tool.

The two aforementioned parts 2 and 3 of the arm 1 are interconnected by means of two elongate connecting elements 11 and 12, each of which is articulated at its ends to the two parts 2 and 3, so as to form with these two parts an articulated parallelogram structure which lies in a vertical plane when the articulated arm 1 is in an installed condition and which, with the variation of its own configuration, makes it possible to vary the height position of the support portion 3 relative to to the fixing portion 2, keeping these two parts 2 and 3 parallel to each other. These movements are illustrated in the sequence of Figures 5A, 5B and 5C.

According to the invention, the two elongate connecting elements 11 and 12 are interconnected by a gas device with differentiated thrust 20, 30, consisting of a gas spring 20 and a mechanical spring 30.

In more detail, the gas spring 20 is installed between the two elongated connecting elements 11 and 12 so that a lowering of the support portion 3 and the corresponding change in configuration of the articulated parallelogram structure. causes compression of the gas spring.

As illustrated in particular in Figure 6, the gas spring comprises a cylinder 24 inside which is inserted a piston 22. The piston 22 divides the internal volume of the cylinder into two chambers 25 and 26 and is moved by a rod 21 coming out of the cylinder 24 through one of the two chambers. In the following description, the chamber through which the rod 21 will be indicated as the second chamber 26, while the other chamber will be indicated as the first chamber 25. The gas spring 30 is housed in the second chamber 26, where is the rod 21.

From the functional point of view, in the compression phase of the gas spring 20 (and thus lowering the load C), the volume of the first chamber 25 is reduced in favor of the second chamber 26. In phase extension (and thus lowering the load C), the opposite occurs.

The mechanical spring 30, pre-loaded, is arranged coaxially with the rod 21 of the gas spring. The mechanical spring 30 acts on only one side of the piston 22 of the gas spring to exert a friction which opposes only the compression of the gas spring itself.

In more detail, as illustrated in FIG. 6, the mechanical spring 30 is inserted between the piston 22 and a shoulder 29 made on the rod 21.

As illustrated in Figures 3, 4 and 5, the gas spring 20 is installed between the two connecting members 11 and 12 to exert its thrust extension, opposing the mass force of the arm 1 and the associated load C, and is dimensioned such that its nominal thrust, added to the pre-load of the mechanical spring 30, maintains in static equilibrium the arm 1 with the associated load C, of predetermined weight, in the absence of thrusts exterior.

From the functional point of view, thanks to the present invention, the arm 1 is able to statically support a load C, remaining in equilibrium in any position in height, in the working intervals (limits imposed by the hinges). The load C must, however, have a weight that falls within the operating limits of the arm 1. Advantageously, the arm 1 and, in particular, the thrust-differentiated gas device may be made in versions with different dimensions so as to cover a wide range of weight to bear.

Moving the load C - upwards or downwards - is obtained simply and conveniently by acting directly on the load C itself.

In more detail, in the upward movement, the operator must simply guide the load C to the desired position. Indeed, the weight of the load C is fully supported by the arm 1. In the downward movement, the operator must only overcome the force of the pre-loaded mechanical spring 30. As will be resumed later, the spring Mechanical 30 is dimensioned in such a way that the force it offers is minimal, to avoid the operator excessive forces and allow conversely movements of the fluid load and easy also down. The gas spring 20 continues to operate, gently accompanying the load downward through a damping action of the movement. The ratio between the thrust provided by the gas spring and that offered by the mechanical spring is indeed significantly unbalanced towards the gas spring. Even in the event of an accidental breakage of the mechanical spring, there would never be a collapse of the load, but only a gradual and slow lowering of the arm would occur. This avoids any risk of accidents for operators and damage to the load.

Whenever the force applied by the operator is zero, the arm 1 reaches the equilibrium condition by locking in the new position. This characteristic of the arm 1 according to the invention allows a user to move the load C in the desired operating zone and to reposition it outside thereof, once the use is complete, without the help or the intervention on keys, levers or references, which was however necessary in the solutions of the known technique.

Preferably, the piston 22 of the gas spring is provided with a device 40 adapted to prevent - during the compression phase of the spring - the passage of gas from the first chamber 25 to the second chamber 26. This device 40 is maintained activated by the thrust exerted by the pre-loaded mechanical spring 30.

From the functional point of view, a lowering of the support portion 3 of the arm 1 and thus a compression of the gas spring 20 are possible only by exerting on the support portion 3 and / or on the associated load C a force such that the corresponding thrust of the piston 22 generates in the first chamber 25 a pressure capable of overcoming the force of the mechanical spring 30, so as to deactivate said device 40 and thus allow the free passage of the gas towards the second chamber 26.

In the extension phase of the gas spring 20, the passage of gas from the second chamber 26 to the first chamber 25 is not prevented by said device 40 and the lifting of the support portion 3 is thus possible without opposing the mechanical spring 30.

In particular, as illustrated in FIGS. 6, 7A and 7B, the piston 22 is traversed by one or more channels 27 and 28 which put in fluid communication the two chambers 25 and 26 of the cylinder 24.

Said device 40 comprising a movable body 41 which is held in abutment against the piston 22 by the pre-loaded mechanical spring 30 to close the mouth of said channels 27 and 28 and thus prevent the flow of gas from the first chamber 25 to the second chamber 26 through these channels in the compression phase.

Advantageously, as shown in FIGS. 6, 7A and 7B, said movable body 41 comprises a seal 42 intended to abut against the piston 22 in correspondence of the mouth of said channels 28.

In particular, said movable body 41 is coaxial with the rod 21 of the gas spring 20 and movable along the rod in opposition to the action of the mechanical spring 30.

According to the preferred embodiment illustrated in FIGS. 6, 7A and 7B, the piston 22 of the gas spring is defined by two plates 22a and 22b which are associated coaxially with the rod 21 and are separated by one of the other by an annular hollow gap 23, inside which is inserted an O-ring seal 43.

A first plate 22a is disposed distal to the mechanical spring 30 and the movable body 41 and adjoins the first chamber 25; a second plate 22b is disposed proximal to the mechanical spring 30 and the movable body 41 and adjoins the second chamber 26.

The O-ring seal 43 is coaxial with the rod 21 and provides a seal on the inner walls of the cylinder 24 of the gas spring to prevent the direct passage of gas between one chamber and the other between the trays 22a and 22b and the inner walls of the cylinder 24. In this manner, the gas is forced through said one or more fluid communication channels 27 and 28 which extend through the trays 22a and 22b and the annular hollow gap. 23.

From the functional point of view, in the compression phase of the gas spring, as shown in Figure 7B, the O-ring seal 43 abuts against the second plate 22b, so as to force the gas to pass through. second plate 22b through the channels 28 which pass through and whose mouth is closed by said movable body 41. The gas flow is indicated in Figure 7B by the arrows in dash G.

In the extension phase of the gas spring, as shown in Figure 7A, the O-ring seals abuts against the first plate 22a, so as to release the passage for the gas through the existing opening between the inner walls of the cylinder 24 and the second plate 22b, thus avoiding that the gas flows through the channels 28 which pass through the second plate 22b and whose mouth is closed by said movable body 41. The gas flow is shown in Figure 7A by the dashed arrows G.

The movable body 41 described above and the O-ring seal 43 are part of said device 40.

Advantageously, as already described above, the gas spring 20 is dimensioned such that its nominal thrust is not sufficient to compensate for the weight of the arm 1 and the load C of predetermined weight. The missing thrust for the weight compensation is provided by the mechanical spring 30. The mechanical spring 30 is dimensioned such that an operator can easily oppose the thrust provided by the mechanical spring itself.

Advantageously, the attachment portion 2 of the arm 1 comprises an anchoring base 4 which is intended to be fixed to a fastening structure F external to the arm 1 rotatively about a first vertical axis XI to allow at the attachment portion 2 and at the entire arm 1 to rotate about said first vertical axis XI, as illustrated in FIG. 2.

Advantageously, the support portion 3 of the arm 1 comprises a hooking base 5 which is intended to support the load C rotatably about a second vertical axis X2 in order to allow the rotation of the load C about said second vertical axis X2, as shown in Figure 2.

According to the embodiment illustrated in particular in Figures 3 and 4, the two elongate connecting elements 11 and 12 are constituted by two box-shaped bodies, juxtaposed longitudinally to one another and free to slide relative to each other in the length direction, to allow configuration changes of the articulated parallelogram structure.

In more detail, a first elongate connecting element 11 is formed by a box-shaped body open on one side to receive said gas-differentiated thrust device 20, 30 inside said gas device. differential pressure 20, 30 is articulated at its two opposite ends to the two elongated connecting elements 11 and 12. The connecting hinges between the gas device differentiated thrust 20, 30 and the elongate elements 11 and 12 are indicated by 13 on the Figures 3 and 4.

In particular, the second elongate connecting element 12 is constituted by a closed box-shaped body. The gas device 20, 30 is hinged externally to this box-shaped body closed on a side facing the open side of the box-shaped body which forms the first elongate connecting member 11. Preferably, the shaped body Closed box forms a passage channel for electrical cables.

According to the embodiment illustrated in the accompanying figures, the two elongated connecting elements 11 and 12 are articulated to the two parts 2 and 3 of the arm 1 in correspondence of connecting plates 6 and 7 fixed to said parts 2 and 3. The connecting hinges between the plates and the elongated elements 11 and 12 are indicated by 13 in FIGS. 3 and 4.

The invention provides many advantages partly already described.

The articulated support arm weight canceller according to the invention is usable by an operator in a more simple and immediate manner compared to the solutions of the known technique, without the need to act on mechanical controls.

Thanks to the absence of the kinematic chain (actuating button, cable and actuating head of the spring) provided in the solutions of the technique, the articulated support arm according to the invention is more reliable from the point of view of the invention. mechanical view. For the same reasons, as well as for the reduction of parts subject to wear, the articulated arm 1 requires less maintenance.

The articulated arm of the invention finally turns out to be easier and more economical by: - reducing the number of parts that make up the system (key, cable, actuating head); - the use of a single gas spring (with differentiated thrust) instead of two separate gas springs; and eliminating the adjustment and adjustment operations of the moving parts (button, cable, actuating head).

All this leads to a reduction in the time and costs of product realization.

Finally, thanks to the absence of the kinematic chain (actuating button, cable and actuating head of the spring), the articulated arm according to the invention proves to be easier to integrate with the instrumentation or the devices (control panel, display, monitor, tool) that it must support. Indeed, it is no longer necessary to integrate in these devices the control key and the transmission cable.

The invention thus conceived therefore achieves the objectives set.

Of course, in its practical embodiment, it may also take forms and configurations different from that illustrated above, without departing from the present protection framework.

In addition, all the details may be replaced by elements equivalent in technical terms and dimensions, shapes and materials used may be any depending on the needs.

Claims (12)

An articulated weight-reducing support arm, comprising a fixing part (2) intended to be associated with a fixation structure external to the arm (1) itself and a support part (3) which is intended to support a load (C) and is movable relative to the fixing part (2) to allow the displacement of said load (C) with respect to the fixing part (2), said two parts (2, 3) of the arm (1). ) being interconnected by means of two elongated connecting elements (11, 12), each of which is articulated at both ends thereof to said two parts (2, 3), so as to form with said two parts (2, 3) ) an articulated parallelogram structure which is in a vertical plane when the articulated arm (1) is in an installed condition and which, with the variation of its own configuration, makes it possible to vary the height position of the support part ( 3) with respect to the fixing part (2), in now these two parts (2, 3) parallel to each other, characterized in that the two elongate connecting elements (11, 12) are interconnected by a gas device with differentiated thrust (20, 30), consisting of: - a gas spring (20) installed between the two elongate connecting members (11, 12) such that a lowering of the support portion (3) and the corresponding change in configuration of the articulated parallelogram structure results in a compression gas spring; and a pre-loaded mechanical spring (30) which is arranged coaxially with the gas spring rod (21) and acts on one side of the piston (22) of the gas spring to exert opposing friction only with the compression of the gas spring itself, the gas spring (20) being installed between the two connecting elements (11, 12) to exert its thrust in extension, by opposing the mass force of the arm ( 1) and the associated load (C), and being dimensioned in such a way that its nominal thrust, added to the pre-load of the mechanical spring (30), keeps the arm (1) in static equilibrium with the associated load (C). ), of predetermined weight, in the absence of external thrusts. The arm of claim 1, wherein the piston (22) divides the gas spring cylinder (24) into a first chamber (25) and a second chamber (26), the mechanical spring (30), and the stem (24). 21) being positioned in the second chamber (26), the piston (22) of the gas spring being provided with a device (40) adapted to prevent - during the compression phase of the spring - the passage of gas from the first chamber ( 25) to the second chamber (26), said device (40) being maintained activated by the thrust exerted by said pre-loaded mechanical spring (30), a lowering of the support portion (3) and thus a compression of the spring to gas (20) being possible only by exerting on the support part (3) and / or on the associated load (C) a force such that the corresponding thrust of the piston (22) generates in the first chamber (25) a pressure which can defeating the force of the mechanical spring (30) to deactivate said device (40) and thus allow the free passage of the gas to the second chamber (26), in the extension phase of the gas spring (20) the gas passage from the second chamber (26) to the first chamber (25) not being prevented by said device (40) and the lifting of the support portion (3) being possible without opposing the mechanical spring (30). 3. Arm according to claim 2, wherein the piston (22) is traversed by one or more channels (27, 28) which put in fluid communication the two chambers (25, 26) of the cylinder (24), said device ( 40) comprising a movable body (41) held in abutment against the piston (22) by said pre-loaded mechanical spring (30) to close the mouth of the aforesaid channels (27, 28) and thereby prevent the flow of gas between the two chambers (25, 26) through these channels in the compression phase. 4. The arm of claim 3, wherein said movable body (41) comprises a seal (42) intended to abut against the piston (22) in correspondence of the mouth of said channels. 5. The arm of claim 3 or 4, wherein said movable body (41) is coaxial with the rod (21) of the gas spring (20). An arm according to one or more of claims 3, 4 or 5, wherein the piston (22) of the gas spring is defined by two plates (22a, 22b) which are coaxially associated with the rod (21) and are separated from each other by an annular hollow gap (23), inside which is inserted an O-ring seal (43) which is coaxial with the rod (21) and seals on the inner walls the cylinder (24) of the gas spring to prevent the direct passage of gas between one chamber and the other between the trays (22a; 22b) and the inner walls of the cylinder and thereby causing the gas to pass through the one or more fluid communication channels (27, 28) extending through the trays (22a; 22b) and the annular hollow gap (23) during the compression phase of the gas spring, the O-ring (43). ) abutting against the second plate (22b) which is proximal to the movable body (41) and the mechanical spring (30), so as to force the gas to pass through the second plate (22b) through the channels (28) which pass through it and whose mouth is closed by said movable body (41), in the extension phase of the gas spring, the sealing O-ring abutting against the first plate (22a) which is distal to the movable body (41) and the mechanical spring (30), so as to releasing the passage for the gas through the opening existing between the internal walls of the cylinder (24) and the second plate (22b), thus avoiding that the gas flows through the channels (28) which pass through the second plate (22b) and whose mouth is closed by said movable body (41). An arm according to one or more of the preceding claims, wherein the gas spring (20) is dimensioned such that its nominal thrust is not sufficient to compensate for the weight of the arm (1) and the load (C) of predetermined weight, the missing thrust for the weight compensation being provided by the mechanical spring (30), the mechanical spring (30) being dimensioned such that an operator can easily oppose the thrust provided by the mechanical spring -even. An arm according to one or more of the preceding claims, wherein the attachment part (2) of the arm (1) comprises an anchoring base (4) which is intended to be fixed to a fixation structure external to the arm (1). ) rotatably about a first vertical axis (XI) to allow the attachment portion (2) and the entire arm (1) to rotate about said first vertical axis (XI). An arm according to one or more of the preceding claims, wherein the support portion (3) of the arm (1) comprises a hooking base (5) which is adapted to support the load (C) rotatably around a second vertical axis (X2) to enable rotation of the load (C) about said second vertical axis (X2). Arm according to one or more of the preceding claims, in which the two elongated connecting elements (11, 12) are constituted by two box-shaped bodies, longitudinally juxtaposed with one another and free to slide one relative to each other in lengthwise direction, a first elongate connecting member (11) being formed by a box-like body open on one side for receiving said gas push-in device (20) 30) articulated on the second elongate connecting element (12). An arm according to claim 10, wherein said second elongate connecting member (12) is a closed box-like body, said differentially pushing gas device (20, 30) being hinged externally to said shaped body. closed box on one side facing the open side of the box-shaped body which forms the first elongated connecting member (11), said closed box-shaped body preferably forming a passage channel for electric cables. Arm according to one or more of the preceding claims, in which the two elongated connecting elements (11, 12) are articulated to the two parts (2, 3) of the arm (1) in correspondence of connecting plates (6, 7). attached to said parts (2,3).