WO1992003774A1

WO1992003774A1 - A control device

Info

Publication number: WO1992003774A1
Application number: PCT/SE1991/000546
Authority: WO
Inventors: Börje PETTERSSON
Original assignee: Pettersson Boerje
Priority date: 1990-08-20
Filing date: 1991-08-20
Publication date: 1992-03-05
Also published as: SE9002691L; AU8424591A; SE467025B; SE9002691D0

Abstract

A control device comprises a lever (1), which is pivotally movable about a pivot centre with respect to a body (2) and has a handle (4) at its end turned away from the pivot centre. The handle is pivotally arranged on the lever about an axis (7).

Description

A control device

FIELD OF THE INVENTION AND PRIOR ART

This invention relates to a control device according to the preamble of claim 1.

Such controls having pivoting levers are present to a great extent on different working machines and vehicles. Forestry machines and vehicles, digging machines, tractors etc may be mentioned as examples. The drivers of such machines and ve¬ hicles are often occupied year after year during the entire working days with operating such lever controls. These drivers are unacceptably frequently subjected to troubles with their arms, shoulders and neck owing to over-exertion. These troubles mean pain and constraint, which gives rise to long periods of sickness. The troubles often turn out to be difficult or impossible to cure which in its turn may necessitate that the driver changes to another task. The troubles occurring depend on the fact that the lever controls known make it necessary to make an angle in the wrist being condemnable from the ergonomic point of view.

Studies of the problem carried out have led to the conclusion that the origin thereof may be found in the circumstance that the lever controls already known have handles being rigidly arranged on the levers and therefor forcing the hand of the driver to follow the handle on pivoting of the lever, so that extremely unsuitable positions of the hand from the anatomical point of view are established. In Figs 1 and 2 an example is illustrated of a known control comprising a lever 1, which is pivotally movable about a pivot centre 3 with respect to a body 2 and has a handle 4 at its end turned away from the pivot centre. When the lever and the handle are pivoted in planes substantially parallel with the longitudinal direction of the forearm 5 of the driver, the hand 6 thereof gripping around the handle will follow the handle and the hand will thereby be brought to make an angle with respect to the forearm by means of the wrist. In particular when the handle 1 is pivoted backwards in the direction towards the driver, the wrist will be exerted to severe strains, since the range of movement with respect to the pivoting of the hand upwardly with respect to the forearm 5 located substantially horizontally will allow a comparatively narrow range of movement. In order to be able to bring the lever 1 sufficiently far backwards at all the driver is mostly forced to more or less open the grip of the hand around the handle. Even in the pivoting forwards illustrated in Fig 1 of the lever 1 from its vertical starting position strains are created, but these are as a rule less serious than those produced on the pivoting backwards of the lever according to Fig 2.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a control device which at least reduces the problems mentioned above with relative positions between the hand and the forearm unsuitable from the anatomical point of view.

This object is obtained by the invention in that

a) the handle is pivotally arranged on the lever about an axis and that

b) the pivotability of the handle with respect to the lever is free in the sense that it does not cause any control function. Through this construction it is achieved that the handle on pivoting to and from of the lever substantially in the longi¬ tudinal direction of the forearm of the driver may pivot freely with respect to the lever, so that the hand of the driver does not have to be turned vertically in a substantial degree with respect to the forearm in an ergonomically unsuitable way.

Advantageous developments of the invention are objects of the dependent claims.

DESCRIPTION OF FURTHER PRIOR ART

By for instance US 4 555 960 it is known per se to arrange a handle turnable or pivotable on a lever in a device according to the preamble of claim 1. However, the handle is there turnably arranged on the lever with the purpose that this turnability shall give rise to a control function. Thus, the relative turning between the handle and the lever acts in the practice upon a transductor, which delivers a control signal depending on the relative position. Thus, it is assumed that the operator on using the control device by vertically turning the hand with respect to the forearm adjusts the relative turn position between the handle and the lever so as to obtain the control function aimed at, which accordingly is obtainable besides that or those obtainable by pivoting the lever about the pivot centre thereof.

Expressed in another way, it is noted that US 4 555 960 concerns a solution being diametrically different from the one aimed at with the present invention; according to US 4 555 960 active vertical turning of the hand with respect to the forearm is assumed to be utilized so as to obtain a control function. The purpose of the present invention is on the other hand to eliminate vertical turning of the hand with respect to the forearm unsuitable for the body by allowing the handle to in the practice pivot freely with respect to the lever while the driver pivots the lever about the pivot centre thereof, by which accordingly the need of relative movement between the hand and the forearm of the driver in the vertical direction is reduced to a substantially lower level than the one at which physiological discomfort occur.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a specific description of embodiments according to the invention cited as examples.

In the drawings:

Figs 1 and 2 are views illustrating a known lever control in different positions.

Figs 3 and 4 are views illustrating the device according to the invention in two different positions,

Fig 5 is a view on an enlarged scale of the control device itself with the lever in a starting position with respect to the body and the handle in a starting position with respect to the lever, and

Fig 6 is a perspective view of a somewhat modified control device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The control devices created in accordance with the invention according to Figs 3-6 comprise a lever 1, which is pivotally movable about a pivot centre with respect to a body 2 and has a handle 4 at its end turned away from the pivot centre. The body 2 is in the example illustrated as having the character of a container open upwardly, in which the pivot centre of the lever 1 is located and established by means well known per se. Thus, the lever 1 projects upwardly from the container through the open end thereof and between the container-like body 2 and the lever 1 a bellow 6 is arranged of a kind known per se protec¬ ting against entrance of contaminations. The lever 1 is at least pivotal in planes substantially parallel to the forearm of a person operating the lever, when this occupies a normal body position with respect to the control device. The pivot movement of the lever 1 gives rise to control functions in that the lever cooperates with control members arranged in connec¬ tion with the body 2 , for instance electrical contacts or fluid valves. These control members are arranged to control the function of tools, such as forestry machines, buckets, cranes etc, connected to the control device.

In many cases, and also in the embodiment examples illustrated in Figs 3-6, the lever 1 is universally pivotable about its pivot centre, so that control functions are also obtained by pivoting the lever laterally.

The handle 4 is pivotally arranged on the lever 1 about an axis 7. The pivot axis 7 is suitably located substantially in the central region of the metacarpus of a person gripping the handle 4 in a normal way. It is preferred that the pivot axis 7 extends substantially perpendicularly to the flat of the hand of a person gripping the handle in a normal way. The construc¬ tion of the handle 4 is such that when a person grips normally therearound, the flat of the hand is orientated substantially parallelly to the lever 1.

The pivotability of the handle 4 about the axis 7 with respect to the lever 1 is free in the sense that it does not cause any control function. Accordingly, this means that the handle 4 is assumed to inactively follow the hand of the driver as far as it concerns the pivoting with respect to the lever 1 while the driver pivots the lever with respect to the pivot centre thereof so as to obtain a control function. As it appears from Figs 3, 4 and 6, the pivot axis 7 is so directed that it extends substantially perpendicularly to the longitudinal direction of the forearm 5 of a person gripping the handle in a normal way. It is in the practice preferred that the pivot axis 7 extends substantially perpendicularly to the longitudinal direction of the lever 1. A central portion of the handle 4 is located substantially just in front of the pivot axis 7.

The handle 4 is pivotally movable with at least a portion thereof located beside at least a portion of the lever. Thus, expressed in another way the lower portion of the handle 4 overlaps the upper portion of the lever 1, as seen in the longitudinal direction of the pivot axis 7, when the lever 1 and the handle 4 occupy the neutral starting position, i.e. when the lever 1 is located in the middle of its pivoting region with respect to the body 2 and the handle 4 is located substantially in the middle of its pivoting region with respect to the lever 1.

As it appears from Figs 3-6, further operating members 8, for instance push buttons, for further control functions may be arranged on the handle 4.

As it appears from Figs 3, 4 and 6, the control device is advantageously arranged in connection with a partly indicated driver's seat. The body 2 of the control device may then by means of suitable securing members 9 be secured with respect to seat portions, which also carry a forearm rest 10. The forearm rest 10 may in order to make it easier for the driver to pivot the lever 1 towards and away from him be constructed as a part movably arranged to and fro in the longitudinal direction thereof, by which the forearm 5 of the driver may rest upon the arm rest 10 when he pivots the lever 1 against and away from himself and the arm rest 10 accordingly follows the forearm in the movement thereof. Means 11, 12 (Fig 5) may be arranged for restricting the freedom of the handle 4 to pivot about the axis 7. At least one 11 of these means is movable with respect to at least two second means 12, the two latter constituting a restriction of the pivot range of the handle with respect to the lever 1. It is indicated in the example how the means 11 is secured to the lever 1, while the means 12 are secured to the part following the handle 4 in its pivoting movement about the axis 7. It would of course also be possible to invert the arrangement so that the means 11 would be secured with respect to the handle 4 while the means 12 would be secured with respect to the lever 1. Although the pivoting range defined by the means 11, 12 may be predetermined, it is also possible that it may be adjusted by the user, for instance by forming the means 12 by stop members in the form of screws as indicated in Fig 5, which are adjustable for variation of the pivoting range by screwing in threaded bores in elements secured with respect to the handle 4 or alternatively to the lever 1.

The pivoting restricting function of the means 11, 12 aims at avoiding the handle 4 to occupy such relative positions with respect to the lever 1 which are of absolutely no interest, i.e. that the means 11, 12 restrict the pivoting possibilities of the handle 4 with respect to the lever 1 to positions not located uncomfortably far away from such pivoting positions which normally occur when a person grips the handle and in¬ fluences the control device.

An elastically flexible cable 13 connected to operating members 8 on the handle 4 is secured with respect to the handle at a first point and with respect to the body 2 at a second point. The cable 13 is suitably so arranged that it by means of the inherent elasticity thereof tends to return the handle 4 to the neutral starting position illustrated in Fig 5 with respect to the lever 1, at least when the latter is in its starting position (central position) , which is normally established by means of one or more return springs as soon as the user release the handle 4. The cable 13 may suitably run in a slope 14 or the like between the securing points with respect to the handle and the body, which provides a cable length sufficient to the pivoting of the lever 1 with respect to the body 2 and the pivoting of the handle 4 with respect to the lever 1.

On a comparison of on one hand Figs 3 and 4 and on the other Fig 6, it appears that the handle construction in the two former Figures is comparatively elongated, wherein the longi¬ tudinal direction of the handle usually extends generally vertically, while the handle in Fig 6 has generally the same extension horizontally and vertically.

As it appears particularly clear when comparing Figs 3 and 4, the handle 4 may on pivoting of the lever 1 towards and away from the driver in the longitudinal direction of the forearm pivot to a required extent with respect to the lever 1 about the pivot axis 7, so that the driver thereby may principally operate the lever 1 without turning the hand vertically with respect to the forearm; the turning required is in any way restricted to modest angles being in no way troublesome for the driver. Thus, in the pivotability between the handle 4 and the lever 1 in accordance with the invention the handle 4 may follow the hand with respect to the pivoting rather than that the hand has to follow the handle as is the case in the prior art.

As appears from Figs 3-5, the lever 1 is thought to be formed by two lever members 15 and 16, respectively. The lever member

15 is then thought to constitute the lever member remaining at the body 2 after cutting the lever off, while the lever member

16 is thought to form a part of a supplement assembly compri¬ sing the handle 4, a pivot axis 7 forming.a bearing arrangement and a securing member 17 secured to the lever member 16, for instance in the form of a clamping arrangement, which is adapted for securing to the lever member 15. The supplemental assembly may accordingly be arranged afterwards on the lever member 15 of a control device obtained after cutting the original lever length off. The supplemental assembly will therefore be suitable for mounting on control devices in the existing stock of machinery and vehicles. When new machines and vehicles are produced the intention is of course to replace the lever members 15 and 16 described by a single lever piece.

The handle and the lever member 16 may also in the embodiment according to Fig 6 have the character of supplemental members, wherein the lever member 16 is thought to have an inner room for receiving the lever member 15 remaining at the body 2 and a securing member 17 arranged on the lever member 16 so as to fix the lever members 15, 16 with respect to each other.

It is evident that the invention is not only restricted to the device described. The expression "pivot axis" used above for the designation 7 should be interpreted in an abstract meaning. As already mentioned above, the freedom of movement of the hand with respect to the forearm is such that normally no problems occur for the driver when he moves the lever 1 laterally by means of the handle 4, i.e. transversely to the longitudinal direction of the forearm. However, it lies within the scope of the invention to construct the handle 4 and the lever 1 pivo¬ tally with respect to an axle directed substantially in the longitudinal direction of the forearm, when there is a need therefor, so that accordingly the handle 4 will not be tilted laterally when the lever 1 is pivoted in such a lateral direc¬ tion. The pivot connection between the handle 4 and the lever 1 could in such an embodiment be constructed as a universal joint, for instance a ball joint, allowing among other things the pivoting discussed of the handle 4 with respect to the lever 1 about the geometrical axis 7. Other modifications are also well possible within the scope of the inventional idea.

Claims

1. A control device of the type comprising a lever (1) , which is pivotally movable about a pivot centre with respect to a body (2) and has a handle (4) at its end turned away from the pivot centre, c h a r a c t e r i z e d in that

a) the handle (4) is pivotally arranged on the lever (1) about an axis (7) and that

b) the pivotability of the handle with respect to the lever is free in the sense that it does not cause any control function.

2. A device according to claim 1, c h a r a c t e r i z e d in that the pivot axis (7) is so located with respect to the handle, that an imaginary prolongation of the pivot axis intersects the metacarpus of a person gripping the handle in a normal way in the central region thereof.

3. A device according to claim 1 or 2, c h a r a c t e r i z e d in that the pivot axis (7) extends substantially perpendicularly to the flat of the hand of a person gripping the handle in a normal way.

4. A device according to any of the claims 1-3, c h a r a c t e r i z e d in that the pivot axis (7) extends substantially perpendicularly to the longitudinal direction of the forearm (5) of a person gripping the handle in a normal way.

5. A device according to any of the preceding claims, c h a r a c t e r i z e d in that the pivot axis extends substantially perpendicularly to the longitudinal direction of the lever (1) .

6. A device according to any of the preceding claims. c h a r a c t e r i z e d in that a central portion of the handle (4) is located substantially just in front of the pivot axis (7) .

7. A device according to any of the preceding claims, c h a r a c t e r i z e d in that the handle (4) is pivotally movable with at least a portion thereof located beside at least a portion of the lever (1) .

8. A device according to any of the preceding claims, c h a r a c t e r i z e d by means (11, 12) for restricting the freedom of the handle (4) to pivot with respect to the lever (1) .

9. A device according to claim 8, c h a r a c t e r i z e d in that the restricting means comprise at least one adjustable member (12) for adjustment of the quantity relating to the freedom to pivot of the handle (4) with respect to the lever (l).

10. A device according to any of the preceding claims, c h a r a c t e r i z e d in that an elastically flexible cable (13) connected to operating members (8) on the handle (4) is secured with respect to the handle at a first point and with respect to the body (2) at a second point, and that the cable (13) is arranged to by means of its inherent elasticity tend to return the handle (4) to a starting position with respect to the lever, at least when this is in a starting position.