DE3014283C2 - Suspension device with rotatable support arm for weight compensation - Google Patents

Description

The invention relates to a suspension device with a rotatably mounted support arm for weight compensation, especially for medical devices, with a spring supported and guided on a curved path Device with lever arms, which is positively and non-positively connected to the support arm.

Such a suspension device is known from FR-OS 22 46 777 The only two-dimensional curved path is provided on the circumference of a cam, which the support arm via a Paralielogrammlenkereinrichiung can adjust. For other suspension devices with weight compensation that have been used so far the spring counterforce is introduced by a rotary movement eccentric to the axis of the support arm (DE-PS 36 787 and US 41 07 769).

The object of the invention is to create a suspension device of the type mentioned above that is compact is built, is easy to assemble and adjust and allows for size-graded series

This object is achieved according to the invention by>: h those cited in the characterizing part of the main claim Characteristics. The subclaims contain further features of the invention.

The inventive solution principle enables both a large pivoting range of the support arm, as also - due to the simple structure of rotation with three-dimensional curvature, which is defined under Spring force (preload) is available - to generate a defined counter torque.

Furthermore, the simple body of revolution allows various sizes graded series for various ^r fi dene surgical lights and their supporting arms or other medical devices at low Hersteilkosten

(Modular principle).

Thus, embodiments of the invention are shown purely schematically in the drawings. It shows
| F i g. 1 the basic structure including the solid of revolution with three-dimensional curvature,

fc: F i g. 2 the balance of power on the swiveling support arm.

yy F i g. 3 the balance of forces for torque compensation.

ff Fig. 4 a development of the curve of the three-dimensional curvature on the, resolved in steps

? $ 55 solid of revolution,

ψ < F i g. 5 an embodiment in half section,

ίξί F i g. 6 shows the cylindrical hollow body from FIG. 5 in detail.

ψ The exemplary embodiments are now explained in detail:

fi As FIG. 1 shows, the body of revolution is a cylindrical body 1. whose curved path la is a spatial one

; Jj 60 has curvature and the axis 4 is coaxial with the pivot axis of the support arm, with a part 3 is designated l} 'net which is displaceable with part 4 is not rotatable but connected.

! "i On the lever arms 5; /. 5b, which are arranged perpendicular to the axis 4, there are rolling elements 5 at the outer end

'stored, which are pressed by the force of a spring 6 against the cam track 1.7. The spring 6 is also

'' Coaxially to the pivot axis 12 or arranged lying in the extension of the central axis of 4 and can be used as a pull

b5 or compression spring. The spring force is to be matched to the cam track i; i in order for the respective

ν application to generate the required counter-torque characteristic.

;: Below is the functional relationship between the cam track, spring force and the

Torque shown.

As in particular from FIG. 2, G is the weight load on the swiveling support arm (introduced via 21 in FIG. 5), F _K the counterforce on the curved path of the cylindrical body 1, /? C; the pivoting radius, Rk the mean radius of the curved path of the cylindrical body , α the swivel angle, M _K the counter torque in the cylindrical body in the cam path. Mc is the torque from the weight load. The following equation for the torque characteristic to be compensated is derived from this

M ₁ ; = Ra- G ■ sin λ 0)

As can be seen from FIG. 3, the balance of forces for the torque compensation can be set on the cylindrical body 1 with the aid of the wedge principle (inclination of the cam path). Here, Fjt is the spring force to generate Fk, S is the spring travel required to generate Fi; ψ the slope of the curve. Cf is the spring rate; Ff is perpendicular to Fk. Frictional forces can be disregarded for the time being. These can be kept small by the roller bearings of the moving parts (5 on Xa). The equilibrium conditions apply here:

15th

Mc = M _K ■ Rc ■ G ■ sin α = Rk ■ F _K (2)

F _K = F _F tan φ mil Ff = SC _F (3)

This results in the required spring travel

c - ^R o ^{G sin α} c - "~ -> M)

R _K ■ Cf tan φ

The production of the cam ring on a numerically controlled machine tool allows the section by section Specification of the curve height or the required spring deflection. Fig. 4 shows the resolved in stages Processing of the curve. Then the curve height Swh. calculate as follows:

S _n = S _n -t + SW- tan g>" (5)

η = number of steps,

φ - < SW = step size for point curve calculation

Inserting this equation in 4 gives:

^^^ 0. (6)

For the individual sections, ^ and S can then be determined as follows:

Because of the required one-sided direction of the counter torque, there is no negative sign for the Root approved.

One possible form of the practical implementation of the principle described above will be based on the following 5 will be explained. The rotation-symmetrical components of the device are in the tubular housing 11, the is closed by the cover plates 22 and 23, arranged. Through the connecting pipe 21, the attachment of the housing indicated (support arm or housing of the load).

The cam ring 13 is firmly attached to the outside in the housing 11 and is on the axis of the opening 34 through a Fitting screw 33 secured against turning. The connection of the spring guide body 14 with the pivot tube 12 takes place through the support disk 19 screwed on at the right end and through the at the rear end End tape 36. As a connection to the pivotable tube 12, the coupling 15 is provided with a Screw connection 31 is secured.

The cam ring 13 corresponds to part 1, the bolts 20 to the lever sockets 5a and 5b and the balls of 28 to parts 5 in FIG. 1.

If a rotary movement is initiated via the coupling 15, the pivotable tube 12, which is in it with The spring guide body 14 plugged into the collar 36 for the spring assembly 30, the pressure washers 16 and the bolts 20 equally moved between the disks 16. This rotary movement is made possible by the deep groove ball bearing 26 and the angular contact ball bearing 29. The ball bearing 28 at the end of the bolt. 20 run on the curved track la of the cam ring 13 fixed in the housing and undertake an axial movement with the Pressure washers 16 under the pressure of the spring assembly 30.

Two longitudinal recesses 35 starting at the right end of the swivel tube 12 lead the disk booms 20 during their axial movement by means of the roller ball bearings 27.

The spring force generating the counter-torque is corresponding to the axial movement of the thrust washers 16 built up by the teüerfederpaket 30. To adjust the spring force, press the ';.' while the clamping nut 17, the is secured by the lock nut 18.

Power supply lines (, / '. Τ the electrical energy supply of a medical device) can through the central bore of the spring guide body 14 and the openings 34 in the cam ring 13 (right) in the

Housing 11 can be laid in the pipe 21.

The cam ring 13 is shown in FIG. 6 shown enlarged in section and in plan view.

The swivel range of the swivel arm 12 is large. With a favorable design of the bearings 28 and the cam ring 13 a swivel angle of 180 ° can be achieved.

For this purpose 4 sheets of drawings

Claims (6)

Patent claims: 1. Suspension device with rotatably mounted support arm for weight compensation, especially for medical Devices with a device supported by a spring and guided on a cam track Lever arms which are connected to the support arm in a non-positive and positive manner, characterized in that, that the cam has a spatial curvature and is arranged on a cylindrical body is, the axis of which is coaxial with the pivot axis of the support arm, and that on the perpendicular to this Pivot axis arranged lever arms rolling elements are mounted, which by spring force against the cam track are pressed, wherein the acting spring is arranged coaxially to the pivot axis ίο 2. Suspension device according to claim 1, characterized in that the entire device is rotationally symmetrical constructed and surrounded by a tubular, closed housing. 3. Suspension device according to claim t or 2, characterized in that in the tubular support arm a tubular spring guide body is firmly inserted, on which a pressure washer to the Spring body arranged compression spring depending on the support arm position more or less axially compresses 4. Suspension device according to one or more of the preceding claims, characterized in that that radially in the thrust washer two acting as a lever arm drive plates are embedded, which at their free ends each have two roller bearings, of which the outer one on the cam track The cam ring fixed to the housing run, while the inner ones run in two longitudinal slots open at the end of the support arm. 5. Suspension device according to one or more of the preceding claims, characterized in that that the mounting of the support arm on the connection side by a deep groove ball bearing arranged in the housing as Fixed bearing takes place, while the bearing is on the closed side of the housing by an angular contact ball bearing is taken over, which at the same time transmits the axial force from the spring tension 6. Suspension device according to one or more of the preceding claims, characterized in that that the adjustment of the compensation device by pretensioning with a nut on the spring guide body he follows.