Small-sized spring arm

Abstract

A spring arm (42) for adjusting the height of a device, wherein the spring arm (42) has a first end region (24) for mounting the spring arm (42) to a first joint (44) and a second end region (26) for mounting the spring arm (42) to a second joint (46) which is designed to accommodate the device, wherein the spring arm (42) comprises: a spindle (64), a compression spring (68), a holding element (70), a vertically pivotable body (22) and a fork-shaped lever bearing (10) having two limbs (12) extending parallel to one another, wherein a lever (56) is rotatably mounted on each limb (12).

Description

[0001] Applicant:

[0002] Ondal Medical Systems GmbH

[0003] Small-dimensioned spring arm

[0004] Technical field

[0005] The present invention relates to spring arms for adjusting the height of devices, wherein a device can be attached to the spring arm by means of a joint. In particular, the invention relates to spring arms which can be smaller in size and preferably allow for improved adjustment of a load capacity.

[0006] State of the art

[0007] In hospitals and medical treatment rooms, devices such as operating lights or diagnostic and / or monitoring monitors are typically suspended with adjustable height to adapt them to the user's needs and position them accordingly. To facilitate the adjustment and positioning of such devices, spring arms are generally used, which—either on their own or in combination with a boom—define a predetermined, potential range of motion for the device attached to the spring arm. The load-bearing capacity of these spring arms is typically adjustable, ensuring that the device attached to the spring arm maintains its height even if the spring arm's angle changes.

[0008] To balance the weight of such a device, a spring-assisted kinematic mechanism is typically used. The kinematic mechanism and the spring are coordinated so that the spring maintains equilibrium in almost any adjustable height position. However, due to the typically nonlinear properties of the kinematic mechanism, this is not always sufficient, so additional friction, for example, is provided at the joints to maintain equilibrium. Known spring arms can have a kinematic mechanism comprising a spindle, a spring tube, and a compression spring. These components are arranged and connected in such a way that when the height of the spring arm is adjusted, for example, when it is pivoted downwards, the spindle is pulled out of the spring tube to the rear.This movement compresses the compression spring coupled to the spindle within the spring tube, increasing the spring force. Simultaneously, a lever connected to the spindle is pushed downwards, bringing it closer to the spring tube axis and reducing the lever arm that generates the torque around the spring tube axis. The increasing spring force and the reduced lever arm are coordinated in such a way that the spring arm remains balanced during changes in the tilt angle, thus maintaining the device's load-bearing capacity.

[0009]

[0010] According to the invention, it was recognized that currently known spring arms have several disadvantages. It was found that existing kinematics require a relatively large spring arm length, especially since the lever, a rear lever bearing, and the compression spring are arranged one behind the other. They are not suitable for constructing a short spring arm, because with a shorter spring arm length, very little installation space would be available for the compression spring. It was recognized that reducing the length of the compression spring is accompanied by a reduction in the number of coils, which makes it comparatively stiff. For an advantageous spring arm kinematic that allows the spring arm to maintain its height position independently in any angular position, it was found that compression springs with the highest possible elasticity are advantageous. Spring arms with a shortened compression spring are accordingly not suitable for maintaining their position in the upper and lower angular positions.Alternatively, the permissible vertical range of movement would have to be significantly restricted in order to achieve reliable self-holding, which is disadvantageous for the user's requirements.

[0011] It was also recognized that when using gas springs, even short lengths provide comparatively low stiffness, making them suitable for spring arm kinematics and enabling self-holding even with a desired large range of motion. Solutions based on gas springs, however, have the disadvantage of developing unavoidable leaks over their service life. Consequently, the gas pressure decreases after a certain period, requiring adjustment of the spring arm or replacement of the gas spring. This increases both the overall effort and the total costs of operating such spring arms. Furthermore, it was recognized according to the invention that adjusting the load capacity is typically very complex due to the intricate arrangement. For example, the load capacity can be adjusted by turning a spindle nut.However, the spindle nut is not accessible from the front when the spring arm is mounted with a front joint. To allow for adjustment, known spring arm systems may have slots in the spring tube; a rod can be inserted through these slots, then into one of the holes in the spindle nut, and used as a lever to turn the spindle nut. When the rod reaches the end of the slot, it must be pulled out and inserted into the next accessible hole in the spindle nut; this process must be repeated until the desired load capacity is set. Adjusting the load capacity is therefore very time-consuming and complicated.

[0012] An alternative method for adjusting the load capacity involves adjusting the height of a bearing block using a setscrew. While the adjustment is relatively quick, the mechanism is complex due to the need for precision-machined parts. Furthermore, it has been observed that the setscrew can shift over time as the spring arm moves, necessitating readjustment.

[0013] Based on the known prior art, it is therefore an object of the present invention to provide a spring arm which has a short longitudinal extent and yet enables reliable balancing of the load over a sufficient angular range. Preferably, the kinematics of the spring arm have a simplified complexity; the kinematics are designed with a small number of parts and can be manufactured cost-effectively. Preferably, the spring arm allows for easy adjustment of the load; moreover, the functionality of the kinematics is ensured even during long-term use without the need to readjust the load or replace components.

[0014] The problem is solved by the subject matter of independent claim 1. Advantageous further developments arise from the dependent claims, the description, and the figures.

[0015] Accordingly, a spring arm for adjusting the height of a device is proposed, wherein the spring arm has a first end region for mounting the spring arm at a first joint and a second end region for mounting the spring arm at a second joint, which is configured to receive the device. The spring arm comprises a spindle, a compression spring arranged around the spindle and extending longitudinally along the spindle, a retaining element that receives the compression spring and is limited at the second end region and fixed axially to the spindle, and a vertically pivotable body that axially limits the compression spring at the first end region. The spindle is displaceably and the compression spring is movably arranged within the body, and the body comprises first receptacles for rotatable mounting with a first axis of the first joint and second receptacles for rotatable mounting with a second axis of the second joint.Furthermore, the spring arm includes a lever bearing, which is connected to the spindle at its first end. The lever bearing is fork-shaped with two parallel arms, each arm having a lever rotatably mounted on it. Each lever has a third receptacle for rotatable mounting with a third axis of the first joint. The levers and the lever bearing are arranged at least partially parallel to the compression spring.

[0016] Due to the fork-shaped design of the lever bearing, it is possible for the lever bearing to be arranged at least partially parallel to the compression spring. In other words, the lever bearing, which can also be referred to as a lever fork, and the compression spring are not arranged completely one behind the other. Rather, the compression spring is at least partially surrounded by the arms of the lever bearing at its first end. This means that part of the lever's length lies next to the compression spring, allowing for significantly shorter overall lengths. This results in a considerable reduction in the overall length of the spring arm. For example, the spring arm can have a length of less than 250 mm or even less than 200 mm between the first and second axes. Such dimensions are not possible with conventional spring arms, which require the lever bearing to be positioned behind the compression spring.For it was recognized according to the invention that the lever cannot be made significantly shorter in such an arrangement, especially since this would noticeably impair the self-holding of the spring arm.

[0017] The arms point towards the second end region, with the levers preferably rotatably mounted on the end region of each arm closer to the second end region via a respective axis on the respective arm. The opposite end of the levers has a third receptacle for the rotatable mounting with the third axis at the first joint. The third axis, which is provided for the mechanical connection of the levers and the lever bearing, differs from the first axis, which is provided for the mechanical connection with the vertically pivoting body. In other words, the third axis and the first axis are not arranged concentrically with the first joint when the spring arm is assembled, but are spaced apart from each other.

[0018] This advantageous arrangement, in addition to significantly reducing the overall length of the spring arm, ensures that the lever arm is adjusted accordingly when the spring arm's height is changed, thus compensating for changes in the compression spring force and enabling balanced positional support. For example, the spindle can be pulled out of the body when the spring arm is pivoted downwards. Because the retaining element axially limits the compression spring at its second end and is axially attached to the spindle, the movement of the spindle compresses the compression spring within the body, thereby increasing the compressive force. Preferably, the axial attachment of the retaining element to the spindle is provided by a preload element that engages with and is connected to the spindle.

[0019] Simultaneously, the movement of the spindle also causes the levers to move downwards, approaching the first axis of the vertically pivoting body. Consequently, the lever arm that provides the torque around the first axis is reduced. In this way, the interaction of the increasing spring force and the correspondingly reduced lever arm ensures that the spring arm remains balanced at every possible swivel angle, even with a reduced overall length, and thus maintains the load-bearing capacity.

[0020] A further advantage is that the kinematics remain essentially unchanged over the entire service life of the spring arm, thus eliminating the need to readjust the load capacity or replace components. This is because the compression spring, which is elastically designed, and the corresponding retaining element advantageously eliminate the need for a gas spring. Preferably, the compression spring is made of a metal or a metal alloy. The retaining element holds and axially limits the compression spring at one end, which corresponds to or is aligned with the second end of the spring arm. At the longitudinally opposite end of the compression spring, the vertically pivotable body holds and axially limits the compression spring.The body can, for example, have a pressure surface and / or receptacle for the compression spring, which is always in engagement with the corresponding end area of ​​the compression spring.

[0021] The vertically pivotable body can function like a conventional spring tube, but is preferably box-shaped rather than tubular. The body can have longitudinally opposed end sections with spaced-apart tabs extending lengthwise from the body, each containing the first or second mounting points. These mounting points are parallel, so that two tabs with a mounting point extend from each end face of the body. The mounting points are parallel to allow for support on both sides at the first and second joints. The body surrounds the compression spring and a section of the spindle, the length of which can vary due to height adjustment of the spring arm caused by the spindle's sliding arrangement.

[0022] The retaining element may have an edge or flange at its second end region, which receives and axially limits the compression spring. The retaining element may be designed as a retaining mandrel to guide the compression spring along its longitudinal extent and prevent it from jamming. For embodiments where the spring arm has a relatively large longitudinal extent and the compression spring is designed accordingly, a sleeve may also be provided adjacent to the retaining mandrel in the direction of the first end region to stabilize the compression spring.

[0023] Preferably, the lever bearing has a continuous recess between the legs; the compression spring is surrounded by the legs. The continuous recess is to be understood such that only the legs extend from the lever bearing towards the second end region, and there is no wall of the lever bearing between the legs, nor above or below the legs, that would define the recess. In this way, a continuous, central opening is provided between the legs, into which at least one section of the compression spring at the first end region is received.

[0024] Preferably, the legs are arranged at least partially parallel to the first end region of the body. The legs can thus surround the body at its first end region. Tabs, which preferably include the first receptacles, can extend longitudinally away from the first end region of the body, so that the tabs are, for example, located below the legs.

[0025] To arrange the legs in a particularly space-saving manner, the body can have lateral cutouts at the first end region to at least partially accommodate the levers and / or the legs. These cutouts can extend from the front face at the first end region of the body, essentially parallel to each other, towards the second end region. The cutouts, which are located on opposite sides of the body, thus provide a continuous opening that leads into a central cavity of the body. The cutouts can, for example, be slot-shaped.

[0026] The cutouts allow, for example, the levers or lever axes, which are preferably mounted rotatably on the inside of the free end of the legs, to extend into or engage with the cutouts when the spindle moves relative to the body. The cutouts can also be dimensioned such that the legs are received within them and are not restricted by the body in either the longitudinal or vertical direction during height adjustment.

[0027] The body can have a through-opening for the spindle at its front face, at the first end region. As described above, the first end region of the body can have a retaining surface and / or receptacle for the compression spring to axially limit the compression spring in the direction of the first end region. Similarly, the front face can be designed to support a sliding arrangement of the spindle within the body. For example, the front face can have a central opening dimensioned to receive the spindle. In this way, the spindle can move out of the body through the through-opening at the first end region if the height of the spring arm is adjusted.

[0028] Accordingly, a particularly compact design of the spring arm can be provided, in which the legs surround at least a section of the compression spring and preferably at least a section of the body, or are even at least partially contained within that section of the body. The through-hole at the end face allows the longitudinal extent of the legs to be further reduced; this is also because the spindle can simply extend through the body and, for example, does not need to be guided parallel to it.

[0029] The inventive design of the lever bearing and its advantageous arrangement further enable the body and / or the lever bearing to be formed as a casting. Preferably, the body and / or the lever bearing are formed as a die-cast part. In this way, the number of parts can be significantly reduced. Furthermore, this also considerably simplifies post-processing and assembly of the spring arm, while simultaneously significantly reducing manufacturing costs. This is because, with a casting design, high production volumes can be manufactured at relatively low costs.

[0030] Tabs, which preferably have the first and second openings and preferably extend from the first end region or the second end region of the body, can therefore be particularly advantageously formed in one piece or monolithically with the body.

[0031] To simplify the design as a casting, the vertically pivoting body is preferably box-shaped. Accordingly, the body can also be referred to as a spring box. With such a box shape, the top can be advantageously open. This not only facilitates the assembly of the compression spring and the retaining element within the body, but also significantly simplifies the die-casting process. For lateral cutouts or through-openings at the end face, lateral slides can be inserted into the box mold during the die-casting process, thus advantageously eliminating the need for machining.

[0032] By designing the lever bearing as a lever fork, an alternative body design is also possible according to the invention, in particular as a box shape. The box shape can, for example, be open on one side, which facilitates or even enables its production as a casting. Such a manufacturing process is not feasible in a conventional spring tube, because a draft angle would be required inside the spring tube to allow the core of the tool to be extracted after casting. To create this draft angle, the outer diameter of the spring tube would have to be significantly increased, which would not only result in a larger component volume and higher costs, but would also be disadvantageous from both an economic and user perspective.

[0033] To facilitate force transmission to the spindle during height adjustment and to prevent accidental spindle rotation, the spindle is preferably connected to the lever bearing in a rotationally secure manner. The spindle can have a radial recess at its first end, into which a pin, extending into a recess in the lever bearing, is received. Alternatively or additionally, the first end of the spindle can be positively engaged by a receptacle in the lever bearing. For example, the spindle can have a suitably shaped head at the corresponding end, which is received in the receptacle and prevents both rotation of the spindle and its removal from the lever bearing, at least forwards. The spindle can thus be rigidly connected or coupled to the lever bearing.

[0034] Preferably, the spindle is guided centrally between the legs and held centrally at the end face of the lever bearing. In a design with a recess and a pin, the recess and the pin, for example a spring pin, can extend in a direction perpendicular to the longitudinal axis of the spindle. In this way, the spindle can be attached directly to the lever bearing.

[0035] However, it can also be provided that the spindle is preloaded at one end face of the lever bearing by the retaining element and the compression spring. Similarly, it can be provided that fastening by means of a pin is omitted. In this way, the spindle can instead be held by the lever bearing by a positive locking mechanism. For example, the spindle can be limited longitudinally at its first end region by the lever bearing and limited and preloaded within the body by the retaining element and the compressive force provided by the compression spring, preferably via a preloading element that engages with the retaining element and is connected to the spindle. Rotation of the spindle can be prevented by a positive locking mechanism provided by an end-face geometry of the spindle with a correspondingly designed and dimensioned receptacle on the end face of the lever bearing.

[0036] A predetermined load capacity can preferably be adjusted by adjusting the compressive force or preload force exerted by the compression spring. Preferably, the body has a recess on its end face at the second end region, into which a preload element is received. This preload element is arranged to be axially displaceable along the circumference of the spindle and engages with the retaining element. The preload element has an actuating element for axial displacement, which extends from the end face of the body at the second end region and / or can be actuated on the end face of the body at the second end region.

[0037] The recess at the second end region can be designed as a continuous recess or opening, which can essentially correspond to the front face of the body. Preferably, the body is box-shaped, so that the second end region can be frame-shaped, with at least two lateral walls extending from the frame towards the first end region. The advantageous design of the body with a recess at the second end region allows for easy operation of the actuating element. To further simplify operation, the second joint, which is attached to the second end region of the body in the assembled state, can preferably also have a through-opening, preferably on its underside. Accordingly, the actuating element can be actuated directly, advantageously directly from the front of the spring arm.

[0038] The preferred design allows for quick and easy adjustment of the spring arm's load capacity, which is not possible with conventional spring arm systems that use a gas spring. The load capacity is adjusted by moving the preload element. By axially moving the preload element, which preferably engages with the second end of the retaining element, the compression spring can be compressed or extended accordingly, particularly when the compression spring is axially connected to the retaining element. The load capacity can be set once for each device by providing the appropriate preload to the compression spring based on the axial position of the preload element.To fix the preload element axially relative to the retaining element, it is preferably provided that the preload element has an internal thread which engages with an external thread of the spindle. The preload element can accordingly be designed as a spindle nut, which shifts axially with each rotation. Because the compression spring does not exert any rotational forces on the retaining element and the preload element, the axial position of the preload element can be maintained. In this way, the retaining element can also be held axially relative to the spindle, particularly when the preload element is (axially) engaged with the retaining element.

[0039] To enable quick and easy rotation of the preload element, the actuating element can be configured for operation with a standard tool. For example, it can be designed as a square drive or with an alternative geometry into which a pin with a corresponding geometry can be inserted, such as a standard square drive pin. A ratchet with a freewheel, onto which the corresponding pin is mounted, can be provided for adjustment and actuation. The recess at the second end of the body and the preferably open design of the underside of the second joint significantly simplify such actuation.

[0040] The rotatable arrangement of the preload element around the spindle offers the advantage of allowing for a wide load capacity range and quick and easy adjustment. This also significantly reduces the number of different spring arm variants required by the user.

[0041] The preloading element and the actuating element are preferably designed as two separate parts, which are held axially and rotationally secure to each other by means of locking elements provided on both parts that interlock positively. The two-part design has the advantage that it enables manufacturing by plastic injection molding, thus significantly reducing production costs. For example, an internal thread in the preloading element can also be injection molded, eliminating the need for subsequent machining. Compared to conventional preloading elements, which, for example, rely on a bearing block mechanism, manufacturing and assembly costs can therefore be considerably reduced.Furthermore, due to its separate design, the actuating element can be easily adapted to the geometry of a tool used to actuate it, for example, based on the geometry of a ratchet element or pin. Alternatively, the preloading element and the actuating element can also be formed as a single unit. This not only reduces the number of components but also prevents, for example, the actuating element and the preloading element from being misaligned.

[0042] Alternatively, the retaining element and the preloading element can also be designed as a single component. This can make manufacturing even more cost-effective, provided that the additional frictional torques that arise when adjusting the load due to the direct contact of the preloading element with the compression spring do not have a detrimental effect.

[0043] The spindle is preferably held radially at the second end region by the preload element and a spindle bearing surrounding the preload element, wherein the spindle bearing and the preload element are advantageously designed such that the spindle bearing axially limits the holding element at maximum extension of the compression spring.

[0044] The spindle bearing can, for example, be designed as an injection-molded plastic part and connected to the inner wall of the body, for instance, via self-tapping screws. The radial support advantageously supports and guides the spindle at its second end. Furthermore, the spindle bearing can, for example, have an edge or step that engages with a corresponding edge or projection on the retaining element when the preload element is extended. This advantageously prevents the preload element and the retaining element from being accidentally pushed out of the body.

[0045] The spring arm can preferably be provided together with the first joint and / or the second joint. Preferably, the spring arm comprises the first joint and a cylindrical pin designed for rotatable mounting on, for example, a boom or a wall bearing, wherein the pin is designed as a separate part and is rigidly connected to the first joint, and wherein the pin and the first joint are advantageously made of different materials.

[0046] This allows the first joint, which can be a rear joint in particular, to be manufactured from a metal or metal alloy comprising or consisting of aluminum, especially by a casting process. The pin can preferably be made of steel or a similarly strong material, which allows the pin to have a comparatively higher strength and wear resistance. This is particularly advantageous under higher loads and bearing capacities of the spring arm. The first joint preferably has fourth receptacles for the third axis on opposite sides, with the levers being connected to the fourth receptacles by means of the third axis. Likewise, corresponding fifth receptacles can be provided on the first joint for the first axis, with the fifth receptacles being spaced apart from the fourth receptacles.

[0047] To attach the pin to the first joint, a screw connection can be provided. Preferably, the pin defines an inner cavity and has two radially opposite cutouts. A screw insert is inserted into each cutout, which has a greater extent on the circumference of the pin in at least one direction than the respective cutout, and the first joint is connected to a section of the respective screw insert in the inner cavity.

[0048] For example, each screw insert has a corresponding receptacle or bore for a screw or bolt, whereby the receptacles can be located in the inner cavity of the pin. The screw inserts can, for example, be designed as segments that are inserted into the cutouts from the outside. For example, self-tapping screws can be screwed through the receptacles into the first joint to connect the pin to the first joint on its underside using the screw inserts.

[0049] Alternatively, the pin and the first joint can be manufactured together as a casting or die-cast part. For example, a pin made of one material, preferably steel, can be placed in a mold and then overmolded with a second material, preferably aluminum or an aluminum alloy. Optionally, the pin and the joint can be manufactured from the same material.

[0050] To minimize the necessary post-processing of a first joint formed as a casting with the pin, the pin can be flattened at its mold parting line. While this may result in a slight burr due to the casting process, the overall radial extent is not increased because of the flattened shape. Consequently, a surrounding bearing surface, for example on a boom, is not contacted by the flattened shape, and therefore no precise and time-consuming removal is required.

[0051] Above the pin, a collar may be provided for the axial support of the first joint. The collar may have a projection or edge on its rear side, i.e., in a direction along the longitudinal extent of the spring arm and away from the spring arm, which serves as a rotation limiter. Preferably, the spring arm includes the second joint, in particular a front joint. The second (front) joint may, in particular, include a holding device for medical devices, tools, interfaces, or monitors.

[0052] The second joint can have a mounting section for the device and two legs extending parallel to each other from the mounting section, which are designed for rotatable mounting on the second end region of the body, wherein the second joint has a continuous recess between the legs. The legs can have six receptacles which are connected to the second receptacles of the body by means of the second axis.

[0053] The design with the continuous recess eliminates the need for pockets or bearing structures that would be required when using a gas spring. Furthermore, the open design with the continuous recess, which is provided particularly on the underside of the second joint, allows the second end of the body to be actuated. This is especially advantageous in a preferred embodiment where the body has a recess at the second end and a preload element with an actuating element housed therein. As described above, this allows for simple and quick adjustment of the set load capacity by actuating the actuating element via the continuous recess at the second (front) joint and the recess at the second end of the body.

[0054] The second joint can define an axis of rotation for the device, which extends essentially perpendicular to the mounting section and is preferably aligned parallel to the legs. For mounting the device, for example an adapter, an operating light, or a monitor, a receptacle or bore can be provided in the mounting section, preferably with a geometry on the upper side corresponding to that of a nut for a bolted connection. The bore is preferably arranged concentrically to the axis of rotation.

[0055] The mounting section may further comprise at least one projection extending circumferentially and providing a rotation limit for the device. The rotation limit can be defined by the projection's circumferential extent and / or by the number and spacing of the projections in the circumferential direction.

[0056] The second joint can further feature sleeve-shaped axles for rotatable bearing at the corresponding receptacles, particularly at the sixth receptacle. The second joint is preferably manufactured as a casting, with the axles being cast directly into it. The axles are preferably mounted directly in the casting, thus eliminating the need for separate bearings. To ensure a sufficient service life, lubrication pockets can be cast directly with the axles. These pockets can be filled with a grease reservoir to provide adequate lubrication throughout the entire service life.

[0057] To ensure parallelism of the second joint across its entire range of motion and to maintain the inclination of the device attached to the second joint, a parallel guide is preferably provided, for example, in the form of a parallel guide rod. The parallel guide is preferably connectable to the first joint at its first end and to the second joint at its second end. The parallel guide typically comprises longitudinally extending side walls that define a recess between the first and second end regions. Projections extend longitudinally from the side walls in a direction perpendicular to the longitudinal direction, defining the boundaries of the recess.

[0058] The parallel guide can thus be connected to a front joint and a rear joint. It is preferably arranged above the body, so that the parallel guide, together with the body, the first joint, and the second joint, forms a parallelogram, which largely maintains the inclination of the first joint even in the case of height adjustment of the spring arm.

[0059] The central recess in the parallel guide, which is open at both the first and second end regions, provides a particularly advantageous guide for at least one cable or guide cable. This is because the fork-shaped lever bearing according to the invention allows for an off-center arrangement of the levers. This keeps the space between the levers clear; at least one cable can be guided through this space without creating a constriction at the lever bearing. In this advantageous combination, the recess in the parallel guide and the opening at the longitudinal end regions allow the at least one cable to be easily guided over the parallel guide and held in place by it.

[0060] Similarly, the at least one cable can be guided down through the opening of the recess towards the second joint. In a preferred embodiment, the second joint has, as described above, a lower continuous recess between the legs, so that the at least one cable can also be easily guided through the second joint at the second end region and, for example, coupled to the device.

[0061] The protrusions that extend into the recess or define its upper edge serve as retainers to prevent the at least one cable from being accidentally pulled out of the parallel guide. Similarly, such protrusions can also be provided on the underside of the parallel guide. Preferably, however, the underside of the parallel guide is essentially continuous to provide sufficient mechanical stability and a connection between the side walls. The underside of the parallel guide may preferably include recesses or openings, which not only reduce the overall weight and material requirements but can also be advantageous for die-casting, thus facilitating manufacturability and production.

[0062] The components of the spring arm are preferably made of a metal or a metal alloy. To simplify the cleaning of the spring arm and the optionally attached joints, and thereby prevent potential contamination in hard-to-reach areas, the spring arm and preferably the optional joints can be enclosed in and contained by plastic covers. This makes it easier to meet hygiene requirements. Such plastic covers can, for example, be provided as injection-molded plastic parts, preferably shell-shaped or as half-shells that can be joined together.

[0063] Preferably, the semi-shell-shaped cover parts for the spring arm form lateral or side cover parts, which are inserted into one another on the sides of the spring arm. The cover parts can each have spaced-apart ribs which, when assembled, are placed onto the third axis or onto domes of the second (front) joint. In this way, the cover parts are pivotally mounted so that they can move along with the height of the spring arm.

[0064] The injection-molded parts can be joined, for example, by means of pockets and locking hooks provided on each fairing part, which interlock when assembled, preferably in a form-fit and / or snap-fit ​​manner. Additionally or alternatively, the fairing parts can also be connected to each other by means of screw connections, whereby the screws can, for example, be designed as self-tapping screws.

[0065] Apart from the semi-shell-shaped cover parts for the spring arm, a cover part for the second (front) joint can also be provided, which is preferably placed onto the second joint, for example from above, and locks into place. Similarly, a cover part for the first (rear) joint can be provided, which is preferably placed onto the first joint from the rear and locks into place on the first axis. Furthermore, semi-shell-shaped cover parts for a vertical section of the first joint can be provided, which, similar to the cover parts for the spring arm, are inserted into each other at the sides of the first joint and lock into place. The cover parts for the spring arm can at least partially accommodate the other cover parts and have a corresponding recess for this purpose.

[0066] It is also possible that pictograms are incorporated into the covers to illustrate the intended operation of the spring arm and / or a joint attached to it, for example by means of arrows indicating a direction of rotation or a direction of height adjustment.

[0067] A bracket for, for example, a cable can be attached to the covers. For instance, a bracket can be clicked into place on the underside of the spring arm. When inserted, this bracket defines a longitudinally extending cavity with a continuous, slot-shaped opening on its underside. This allows one or more cables to be routed very quickly from the first joint to the second joint and the device attached to it. To prevent the cable from accidentally moving out of the cavity through the opening, inserts are preferably provided. These inserts have numerous protrusions or springs that engage in corresponding grooves within the insert, thus securing it to the bracket. Each insert has lamellae that extend into the opening and / or at least partially define it.In this way, an inserted cable is held in place by the slats; it can be prevented from slipping out of the slot.

[0068] To facilitate the insertion of a cable into the cavity, the lamellae are preferably made of a flexible material, so that a cable can simply be pressed into the cavity, whereby the weight of the cable itself should not exceed the holding force of the lamellae.

[0069] Brief description of the characters

[0070] Preferred further embodiments of the invention are explained in more detail by the following description of the figures. They show:

[0071] Figure 1 is a perspective side view of a fork-shaped lever bearing according to the invention; Figure 2 is a perspective side view of a vertically pivotable body according to the invention; Figure 3 is a side view of a spring arm according to the invention;

[0072] Figure 4 is a longitudinal section of the spring arm according to Figure 3; Figure 5 is a longitudinal section of the spring arm according to Figure 4 during height adjustment of the spring arm; Figure 6 is a perspective side view of a preload element according to the invention;

[0073] Figure 7 shows a longitudinal section of the prestressing element according to Figure 6;

[0074] Figure 8 shows a perspective side view of an actuating element according to the invention;

[0075] Figure 9 shows an upper sectional view of the spring arm according to Figure 3;

[0076] Figure 10 shows an upper sectional view of the spring arm according to Figure 9 with an adjusted load capacity of the spring arm;

[0077] Figure 11 shows a perspective side view of a first joint for the spring arm according to the invention;

[0078] Figure 12 shows a perspective side view of a second joint for the spring arm according to the invention;

[0079] Figure 13 shows a perspective side view of the spring arm according to Figure 3 with fairing parts; Figure 14 shows a longitudinal section of the spring arm according to the invention according to Figure 3 with guided cable; Figure 15 shows the parallel guide according to Figure 14 in a perspective detail view;

[0080] Figure 16 shows a first joint for the spring arm according to the invention in one embodiment;

[0081] Figure 17 shows a pin for the first joint according to Figure 16;

[0082] Figure 18 shows a screw element for attaching the pin according to Figure 17 to the first joint according to Figure 16;

[0083] Figure 19 shows the pin according to Figure 17 in the attached state at the first joint according to Figure 16 from a lower perspective view;

[0084] Figure 20 shows a bottom view of the first joint according to Figure 19; and

[0085] Figure 21 shows a side view of a spring arm with a lever bearing according to the invention in an overall system.

[0086] Detailed Description of Preferred Embodiments: The following section describes preferred embodiments with reference to the figures. Identical, similar, or equivalent elements in the different figures are designated with identical reference numerals. Repeated descriptions of these elements are sometimes omitted to avoid repetition.

[0087] The spring arm 42 according to the invention, with its fork-shaped lever bearing, is shown in a side view in Figure 21 as part of a complete system. The spring arm 42 is connected at its rear end to a boom 43 via a first joint 44 and at its front end to a device 47, in this example a monitor, via a second joint 46 and a joint assembly 45. In this way, the spring arm 42 can be pivoted in a horizontal plane relative to the boom 43 via the first joint 44. The first joint 44 also allows for tilt adjustment of the spring arm 42 relative to the boom 43 to enable height adjustment of the monitor. Instead of a boom 43, the spring arm 42 can also be connected to a wall bracket, or the boom 43 can be connected to another boom or a wall bracket.Furthermore, the position of the monitor can optionally be adjusted, at least in its tilt, via a horizontal axis of rotation using the joint group 45.

[0088] As described above, according to the invention a considerably shorter design of the spring arm 42 is made possible, in particular due to the advantageous design of the lever bearing, as described below with reference to the further figures.

[0089] Figure 1 shows a lever bearing 10 according to the invention for a spring arm in a perspective side view. It can be seen that the lever bearing 10 is fork-shaped and has two legs 12 which extend parallel to each other and are aligned along a longitudinal direction of the spring arm when assembled. A continuous recess is provided between the legs 12, so that the lever bearing 10 is open between the legs 12. This design is particularly advantageous, especially if the lever bearing 10 can thereby at least partially surround a compression spring and preferably a body that receives the compression spring, as shown, for example, in Figures 3 and 4. Accordingly, the lever bearing 10 can be arranged at least partially next to or parallel to a section of the body and the compression spring, which significantly reduces the overall length of the spring arm.

[0090] The lever bearing 10 has two receptacles 14 for support at a first joint, into which a fourth axis can extend, which is connected to the first joint by corresponding levers. The receptacles 14, which are preferably designed as through-holes in a casting configuration, but can alternatively be provided as bores, are arranged parallel to each other and at a free end region of the respective leg 12. The levers can be guided in a groove 16 of the respective leg 12.

[0091] The lever bearing 10 can be mounted on the first joint via the levers and the receptacles 14. Furthermore, the lever bearing has a receptacle 18 into which, when the lever bearing 10 is mounted, the end face of a spindle is inserted. To prevent the spindle from rotating, the lever bearing 10 has a recess 20 on its upper surface, which extends into the receptacle and through which a pin can be guided to engage in a corresponding radial recess on the end face of the spindle. In this way, it can be easily prevented, for example by pressing in or pulling in a dowel pin, that the spindle will not rotate accidentally when the preload element is turned.

[0092] Figure 2 shows a corresponding vertically pivotable body 22, which, in the assembled state, is at least partially surrounded by the lever bearing 10. The body 22 is box-shaped, which makes it particularly advantageous to manufacture it as a casting. The body has a first end region 24 and a second end region 26 opposite the first end region 24 in the longitudinal direction. The body 22 defines an inner cavity 28 between the end regions 24 and 26, into which a compression spring mechanism and a spindle are received in the assembled state. In the assembled state, the spindle is slidably mounted in the inner cavity 28 and extends through a through-opening 30 at the first end region 24. One end face of the spindle is received by the receptacle 18 of the lever bearing 10.

[0093] To enable a particularly compact design, the body 22 further features cutouts 32, which are arranged laterally and extend from the first end region 24 towards the second end region 26. The cutouts 32 can accommodate the inner fourth axes of the levers, or alternatively, they can be dimensioned such that the legs 12 of the lever bearing 10 can be at least partially accommodated within them. The slot-shaped cutouts 32 allow the levers to move accordingly when the height of the spring arm is adjusted.

[0094] At end regions 24 and 26, the body 22 further features tabs 34 extending longitudinally from the respective end faces. The tabs 34 have first receptacles 36 at the first end region 24 and second receptacles 38 at the second end region 26, configured for rotatable mounting at the first and second joints, respectively. In the assembled state of the lever bearing 10, the tabs 34 at the first end region 24 extend below the lever bearing 10, thus enabling a particularly compact design.

[0095] At the second end region 26, a recess 40 is also located on the front face of the body 22. The recess 40 enables or facilitates the insertion of further components of the spring mechanism, such as the compression spring, a preload element, and an actuating element. Likewise, this allows the actuating element to be easily actuated at the second end region 26, particularly from the front of the body 22, when the assembly is complete.

[0096] Figure 3 shows a side view of a spring arm 42 according to the invention in an advantageous embodiment. The spring arm 42 has a (rear) first joint 44 at its first end region 24 and a (front) second joint 46 at its second end region 26. The body 22 is mounted to the first joint 44 via a first axis 48 and corresponding receptacles 36. At the second end region 26, the body is mounted to the second joint 46 via a second axis 50 and second receptacles 38.

[0097] The lever bearing 10 is mounted at the first joint 44 via parallel levers 56, which provide a connection between a third axis 52 at the first joint 44 and a fourth axis 54 at the receptacles on the free end of the legs 12. The third axis 52 and the first axis 48 are spaced apart and arranged such that the levers 56 move closer to the first axis 48 when the height of the spring arm 42 is adjusted. In this way, the torque at the first joint 44 can be reduced accordingly, so that compressive forces arising from a height adjustment of the spring arm 42 can be balanced, as will be further explained with reference to the following figures.

[0098] In addition, the spring arm 42 in the present embodiment has a parallel guide 58 which is mounted at the first end region 24 via a fifth axis 60 and at the second end region 26 via a sixth axis 62 at the first joint 44 and the second joint 46, respectively. The parallel guide 58 thus forms a parallelogram together with the first joint 44, the second joint 46, and the body 22. This allows the relative inclination of the second joint 46 to be maintained even when the height of the spring arm 42 is adjusted.

[0099] Figure 4 shows a detailed longitudinal section of the kinematics of the spring arm 42. In particular, this figure illustrates how the spindle 64 extends through the cavity 28 of the body 22 and through the through-opening 30. The end face of the spindle 64, which protrudes from the first end region 24 of the body 22, is secured against rotation by a pin 66 to the lever bearing 10. The spindle 64 is thus held at one longitudinal end region by the lever bearing 10 and at the opposite end region by a spindle bearing 74 at the second end region 26 of the body 22. The lever bearing 10 is only indirectly connected to the body 22 via the spindle 64.

[0100] In the inner cavity 28 of the body 22, the spindle 64 is surrounded by a compression spring 68, which is held by a retaining element 70. The retaining element 70 is designed as a retaining mandrel and has a step towards the second end region 26, which serves as a receptacle for the corresponding end region of the compression spring 68. The retaining element 70 is axially limited by a preloading element 72, so that one end region of the compression spring 68 is limited by the retaining element 70 and the position of the preloading element 72. The longitudinally opposite end region of the compression spring 68 is axially limited by the end face of the body 22 at the first end region 24. A bearing can be provided for this purpose, which is inserted into the body 22 at the level of the end face. Accordingly, the compression spring 68 is preloaded to a compressive force, which preferably corresponds to a predetermined load capacity.

[0101] To adjust the compressive force, the preload element 72 can be displaced axially relative to the spindle 64. For this purpose, the preload element 72 has an internal thread that engages with an external thread of the spindle 64. The axial displacement of the preload element 72 is effected by an actuating element 76, which is coupled to the preload element 72 and can be actuated at the second end region 26 of the body 22 via the recess 40. For example, the actuating element 76 can be turned with a standard tool, such as a ratchet, to cause the preload element 72 to rotate, with the rotation being converted into an axial displacement due to the thread. In this way, the compression spring 68 can either be further preloaded to generate a higher compressive force, or a longer longitudinal extension of the compression spring 68 can be set, resulting in a correspondingly reduced compressive force.

[0102] A corresponding interaction between the position of the spindle 64, the lever 56, and the compressive force is shown in Figure 5, where the spring arm 42 at the second end region 26 was pressed down, as indicated by the arrow, to provide a height adjustment. It can be seen that this caused the spindle 64 to be pulled further out of the body 22. Because the preload element 72 is held axially to the external thread of the spindle 64 by means of the internal thread, the retaining element 70 is pressed towards the first end region 24 by the axial movement of the spindle 64, thereby compressing the compression spring 68 and increasing the compressive force accordingly. Simultaneously, the levers 56 are rotated towards the first axis 48, which shortens the corresponding lever arm and reduces the torque, thus balancing the increased compressive force.Accordingly, the preferred embodiment provides a particularly advantageous kinematics, whereby a height position of a device attached to the second joint 46 is maintained.

[0103] Furthermore, Figure 5 illustrates that the inclination or principal extension of the second joint 46 does not change even when the height is adjusted, due to the arrangement of the parallel guide 58. This allows, for example, a user-friendly tilt of a monitor attached to the second joint 46 to be maintained.

[0104] Figures 6 and 7 show an advantageous embodiment of a preload element 72. The preload element 72 is essentially sleeve-shaped and has an enlarged circumference at one end region, which, in the assembled state, is aligned with the second end region 26 of the body 22, so that a step and a corresponding receptacle for the retaining element 70 are formed. A recess is provided at the corresponding end region into which the actuating element 76 can be received, with radial ribs being provided to limit the rotation of the actuating element within the recess and to support rotation of the preload element 72 when the actuating element 76 is actuated. Detent hooks on the end face further enable the actuating element 76 to be positively engaged with the preload element 72.

[0105] At the opposite, narrower end region of the preloading element 72, the sleeve has an internal thread on its inside, which engages with an external thread of the spindle 64 when assembled.

[0106] An example of an actuating element 76 is shown in Figure 8. The actuating element 76 has several grooves spaced apart around its circumference, into which the radial ribs of the preloading element 72 are received in the assembled state. Furthermore, the actuating element 76 includes a receptacle, which is designed, for example, to receive a pin of a rotary tool. Accordingly, while the geometry shown in the present example is advantageous for commercially available tools, it is not limited to them. Rather, the preloading element 72 can also be configured for actuation with different tools by replacing the actuating element 76 accordingly. The preferred two-part design of the preloading element 72 and the actuating element 76 can significantly facilitate such adaptation.Figures 9 and 10 illustrate an axial adjustment of the preload element 72 and the corresponding effect on the compression spring 68. If the preload element 72 is displaced towards the second end region 26, preferably by rotation of the preload element 72, not only are the preload element 72 and the actuating element 76 moved towards the second end region 26, but the compression spring 68 is also extended. The preload element 72 and the actuating element 76 can extend at least partially into a continuous recess 82 of the second joint 46, which is defined by the legs 80 of the second joint 46.

[0107] While the position of the body 22 and the spindle 64 remains unchanged in the axial direction, the preload element 72 and the actuating element 76 move out of the body 22 accordingly. The resulting expansion of the compression spring 68 also increases the distance between the coils, thus reducing the compressive force. In this way, the compressive force can be adjusted, for example, for a lower load capacity in order to maintain the height position of the spring arm 42.

[0108] The spindle bearing 74 advantageously serves not only to support the spindle 64. It preferably also forms a step which engages with the retaining element 70 when the preload element 72 is further extended or rotated out. This prevents further extension of the preload element 72, so that the preload element 72 is not accidentally removed completely from the body 22.

[0109] Figures 11 and 12 show preferred embodiments of a first joint 44 and a second joint 46 respectively, which are preferably attached to the spring arm 42 according to the invention.

[0110] The first joint 44 has a pin 84 on its underside. The first joint 44 and the pin 84 are preferably manufactured together as a casting or die-cast part. The pin 84 has a flattened area 92 at its mold parting line to prevent any slight burr from contacting a surrounding bearing surface, for example, on a boom. A collar 94 is provided above the pin 84 for the axial support of the first joint 44. The collar 94 optionally has a projection 96 or edge on its rear side, i.e., in a direction along the longitudinal extent of the spring arm 42 and away from the spring arm 42, which serves as a rotation limiter.

[0111] To facilitate mounting at the first joint 44, the first joint 44 has several parallel mountings on its upper surface. Fifth mountings 86 are provided for mounting the body 22 by means of the first axis 48, fourth mountings 88 for mounting the lever bearing 10 or the levers 56 by means of the third axis 52, and seventh mountings for mounting the parallel guide 58 by means of the fifth axis 60.

[0112] The second joint 46 of the spring arm 42 is shown in Figure 12 in a preferred embodiment. The second joint 46 is preferably a front joint to which a device can be attached.

[0113] The second joint 46 comprises two legs 80, which are aligned parallel to each other and each have a sixth receptacle 98 for supporting the body 22 via the second axis 50 and an eighth receptacle 100 for supporting the parallel guide 58 by means of the sixth axis 62. A continuous recess 82 is provided between the legs 80, making the recess 40 on the body 22 easily accessible (from the front).

[0114] To attach a device to the second joint 46, the second joint 46 has a corresponding mounting section 102, which extends essentially in a plane perpendicular to the legs 80. The mounting section 102 defines an axis of rotation that coincides with or is arranged concentrically to a receptacle 104. Preferably, a device can be coupled to the second joint 46 at the underside of the mounting section 102, the receptacle 104 being designed to receive a screw connection, preferably a bolt connection. In the present example, the receptacle 104 has a predefined geometry on its upper side, which corresponds to the geometry of a nut for a bolt connection, for example, a hexagonal nut.

[0115] At least one projection 106 can be provided on the underside of the mounting section 102, extending circumferentially and providing a rotation limit for a mounted device. The rotation limit can be defined by the circumferential extent of the projection 106 and / or by the number and spacing of the projections 106 in the circumferential direction.

[0116] Figure 13 shows the spring arm 42 according to Figure 3 in a rear perspective side view with its cover parts. This allows the kinematics of the spring arm 42, as well as the first joint 44, the second joint 46, and the bearings, to be completely protected from the outside. The cover parts for the spring arm 42 are designed as half-shells that are laterally inserted into one another and connected to each other by means of locking devices. These cover parts also have ribs that are inserted around the first axis 48 at the first joint 44 and onto corresponding bosses at the second joint 46, thus enabling the cover parts to be rotatably mounted on the spring arm 42 and on the joints 44 and 46, respectively.

[0117] Apart from the side fairing parts for the spring arm, rear fairing parts for the essentially cylindrical section of the first joint 44 and an upper fairing part for the second joint 46 are also shown.

[0118] Figure 14 shows a longitudinal section of the spring arm 42 according to the invention as shown in Figure 3 in a preferred embodiment with a guided cable. As described above, the fork-shaped lever bearing 10 according to the invention allows the levers 56 to be arranged off-center and thus define a cavity which is not affected by the lever bearing 10, the first joint 44, or the spindle 64, even in the case of height adjustment of the spring arm 42. Accordingly, a cable can advantageously be guided between the levers 56 to facilitate routing a cable from the first joint 44 to the second joint 46.

[0119] This feature can be used even more advantageously by providing additional cavities. For example, the cable can also be guided through a cavity 108 of the first joint 44. Because the first joint 44 is primarily configured for rotatable mounting on a cantilever via the corresponding pin 84, the cable's guidance within the cavity 108 is not affected by any movement of the first joint 44, even when it rotates. Furthermore, the parallel guide 58 preferably has a recess 110, preferably on its upper surface, so that the cable can be efficiently guided through the cavity 108 and between the levers 56 to the recess 110 and routed within the recess 110 towards the second end region 26. The recess 110 is correspondingly open at its longitudinal end regions.

[0120] At the second joint 46, the cable can then preferably be led out of the second joint 46 via the recess 82 and connected to a device attached to the second joint 46.

[0121] A corresponding embodiment of the parallel guide 58 is shown in Figure 15. The recess 110 can optionally be limited on its upper side by projections 112, which extend laterally into the recess 110, to prevent the cable from being accidentally moved out of the recess 110. Alternatively, a retaining element can be formed by an adjacent upper cladding segment.

[0122] For the purpose of supporting the parallel guide 58 at the first joint 44 and at the second joint 46, the parallel guide 58 has corresponding tenth receptacles 116 and ninth receptacles 114 at its longitudinal end regions, which in the assembled state are connected to the fifth axis 60 and the sixth axis 62 respectively.

[0123] Figures 16 to 20 show an alternative embodiment of the first joint 44, wherein the pin 84 is designed as a separate component. For fastening the pin 84, the pin 84 has two opposing cutouts 118 on its circumference, which are slot-shaped and configured to receive a screw insert 120. The screw inserts 120 each have a receptacle 122 for a screw 124 or a bolt. The screw inserts 120 each have steps which are designed such that, when inserted, they engage in the cutouts 118 with longitudinal chamfers, so that the screw inserts 120 are held on the circumference and preferably flush with the outer surface on the circumference of the pin 84.

[0124] When inserted, the receptacles 122 lie within the cavity 108, and are arranged such that they overlap with receptacles on the underside of the first joint 44, allowing the screw inserts to be fastened to the first joint 44 by means of screws 124. The interaction of these features is shown in Figures 19 and 20 in a perspective lower side view and a bottom view.

[0125] Where applicable, all individual features shown in the exemplary embodiments can be combined and / or exchanged without leaving the scope of the invention.

[0126]

[0127] 10 lever bearings

[0128] 12 thighs

[0129] 14th entry

[0130] 16 Nut

[0131] 18 recording

[0132] 20 recesses

[0133] 22 bodies

[0134] 24 first end area 26 second end area 28 cavity

[0135] 30 Passage opening 32 Cutout

[0136] 34 tab

[0137] 36 first shot 38 second shot 40 recess

[0138] 42 Spring arm

[0139] 43 outriggers

[0140] 44 first joint

[0141] 45 Joint group 46 Second joint 47 Device

[0142] 48 first axis

[0143] 50 second axis

[0144] 52 third axis

[0145] 54 fourth axis

[0146] 56 levers

[0147] 58 Parallel guidance 60 fifth axis

[0148] 62 sixth axis

[0149] 64 spindle

[0150] 66 pens

[0151] 68 Compression spring

[0152] 70 Holding element 72 Preload element 74 Spindle bearing 76 Actuating element 78 Mount

[0153] 80 thighs

[0154] 82 recess

[0155] 84 cones

[0156] 86 fifth recording 88 fourth recording 90 seventh recording 92 flattened area 94 federal

[0157] 96 lead

[0158] 98 sixth recording 100 eighth recording 102 fastening section 104 recording

[0159] 106 lead

[0160] 108 Cavity

[0161] 110 recess

[0162] 112 lead

[0163] 114 ninth recording 116 tenth recording 118 excerpt

[0164] 120 screw insert

[0165] 122 recording

[0166] 124 screw

Claims

Claims 1. Spring arm (42) for adjusting the height of a device, wherein the spring arm (42) has a first end region (24) for mounting the spring arm (42) on a first joint (44) and a second end region (26) for mounting the spring arm (42) on a second joint (46) which is designed to receive the device, wherein the spring arm (42) comprises: a spindle (64), a compression spring (68) which is arranged around the spindle (64) and extends in the longitudinal direction of the spindle (64), a retaining element (70) which receives the compression spring (68) and is limited at the second end region (26) and fixed axially to the spindle (64), a vertically pivotable body (22) which axially limits the compression spring (68) at the first end region (24), wherein the spindle (64) is slidably arranged and the compression spring (68) is movably arranged within the body (22), and wherein the body (22) comprises first receptacles (36) for rotatable mounting with a first axis (48) of the first joint (44) and second receptacles (38) for rotatable mounting with a second axis (50) of the second joint (46), and a lever bearing (10) which is connected to the spindle (64) at the first end region (24), wherein the lever bearing (10) is designed in a fork shape with two legs (12) extending parallel to each other, wherein a lever (56) is rotatably mounted on each leg (12), wherein the levers (56) each have a third receptacle for rotatable mounting with a third axis (52) of the first joint (44), and wherein the levers (56) and the lever bearing (10) are arranged at least partially parallel to the compression spring (68).

2. Spring arm (42) according to claim 1, wherein the lever bearing (10) has a continuous recess between the legs (12) and the compression spring (68) is surrounded by the legs (12).

3. Spring arm (42) according to claim 1 or 2, wherein the legs (12) are arranged at least partially parallel to the first end region (24) of the body (22).

4. Spring arm (42) according to any one of the preceding claims, wherein the body (22) has lateral cutouts (32) at the first end region (24) for at least partially receiving the levers (56) and / or the legs (12).

5. Spring arm (42) according to one of the preceding claims, wherein the body (22) has a through opening (30) for the spindle (64) at its end face at the first end region (24).

6. Spring arm (42) according to one of the preceding claims, wherein the body (22) and / or the lever bearing (10) is / are formed as a casting.

7. Spring arm (42) according to one of the preceding claims, wherein the spindle (64) is connected to the lever bearing (10) in a rotationally secure manner, wherein the spindle (64) has a radial recess at the first end region (24) in which a pin (66) extending into a recess (20) on the lever bearing (10) is received and / or wherein the first end region (24) of the spindle (64) is positively engaged by a receptacle (18) of the lever bearing (10).

8. Spring arm (42) according to one of the preceding claims, wherein the body (22) has a recess (40) at its end face at the second end region (26) in which a preload element (72) is received, which is arranged to be axially displaceable along the circumference of the spindle (64) and engages with the retaining element (70), wherein the preload element (72) has an actuating element (76) for axially displacing the preload element (72), which extends from the end face of the body (22) at the second end region (26) and / or is actuated at the end face of the body (22) at the second end region (26).

9. Spring arm (42) according to claim 8, wherein the preload element (72) has an internal thread which engages with an external thread of the spindle (64).

10. Spring arm (42) according to claim 8 or 9, wherein the preload element (72) and the actuating element (76) are designed as two separate parts which are held axially and rotationally secure to one another by means of detent elements provided on both parts which interlock positively.

11. Spring arm (42) according to any one of claims 8 to 10, wherein the spindle (64) is radially held at the second end region (26) by the preload element (72) and a spindle bearing (74) surrounding the preload element (72), wherein the spindle bearing (74) and the preload element (72) are designed such that the spindle bearing (74) axially limits the holding element (70) at maximum extension of the compression spring (68).

12. Spring arm (42) according to one of the preceding claims, comprising the first joint (44) and a cylindrical pin (84) which is designed for rotatable mounting on a boom, wherein the pin (84) is designed as a separate part and is rigidly connected to the first joint (44), and wherein the pin (84) and the first joint (44) are made of different materials.

13. Spring arm (42) according to claim 12, wherein the pin (84) defines an inner cavity (108) and has two radially opposing cutouts (118), wherein a screw insert (120) is inserted into each cutout (118), which has a greater extent on the circumference of the pin (84) in at least one direction of extension than the respective cutout (118), and wherein the first joint (44) is connected to a section of the respective screw insert (120) in the inner cavity (108).

14. Spring arm (42) according to one of the preceding claims, comprising the second joint (46), wherein the second joint (46) has a mounting section (102) for the device and two legs (80) extending parallel to each other from the mounting section (102), which are designed for rotatable mounting on the second end region (26) of the body (22), and wherein the second joint (46) has a continuous recess (82) between the legs (80).

15. Spring arm (42) according to one of the preceding claims, comprising a parallel guide (58) which can be connected at the first end region (24) to the first joint (44) and at the second end region (26) to the second joint (46), wherein the parallel guide (58) comprises longitudinally extending side walls which define a recess (110) between the first end region (24) and the second end region (26), wherein projections (112) extend longitudinally from the side walls in a direction perpendicular to the longitudinal direction, which limit the recess (110). Summary

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