GB2328005A

GB2328005A - Arrangement of hand actuated control levers for operating a displacing mast lift truck

Info

Publication number: GB2328005A
Application number: GB9817279A
Authority: GB
Inventors: Eike Schubert; Kai-Alexander Hestermann
Original assignee: Jungheinrich AG
Current assignee: Jungheinrich AG
Priority date: 1997-08-09
Filing date: 1998-08-07
Publication date: 1999-02-10
Anticipated expiration: 2018-08-07
Also published as: GB2328005B; DE29714284U1; GB9817279D0

Abstract

Three operating levers 10, 12, 14 are arranged next to one another in the travelling direction of the lift truck and mounted on a common horizontal shalt 30. Each lever has a lever head 16, 18, 20 which can be grasped and actuated by placing on a hand from above and a lever section 24, 26, 28 coupled to a respective hydraulic valve. The inner lever 10 lying nearest the driver effects the lifting and lowering of the load carrying means while the other levers 12, 14 effect the displacing and inclining of the mast. Seen from above, the centres of the lever heads 16, 18, 20 lie on an arcuate line 40 so that, on changing the grasping of a lever head, an elbow supported on an underlay can substantially keep its position. The nearest lever head 10 may have a thumb switch 42 and a horn button 46.

Description

1 2,'5 2- Z 0 0 5 1 A Hand Actuated Control Device for the Operatin

Condition or Situation of a Displacing Mast Lift Truck The invention relates to a hand actuated control device for the operating condition or situation ofa displacing mast lift truck.

The driver of a displacing mast lift truck must operate not only the driving motor but also the conveying means, specifically the load carrying means (lifting and lowering), the forward and return displacement of the mast, the inclination of the mast and where appropriate the lateral displacement of the load carrying means (load carriage). From 11jungheinrich- Schubmaststapler RetrakIl it is known for the functions "lifting and lowering", "mast forward displacement", "mast inclination" and "mast lateral displacerll to mount separate valve levers next to the driver's seat. On the operating panel there is further provided a separate travelling direction switch and a horn switch. The operating person must exert considerable concentration to operate in each case the correct lever and not to carry out an undesired actuation. Each operating or valve lever has its own mounting and is correspondingly coupled to hydraulics.

German Gbm 94 17 838 discloses a hand actuated control device provided with a single control member which is movable in two operating planes perpendicularly standing on one another in order to permit a lifting and lowering of the load carrying means or a displacement of the mast. on the control member there is laterally mounted an intermediate switch for the functions lateral displacement and travelling direction. The intermediate switch produces electrical signals as does the control member PIkkLurther toggle switch on the control member serves for a4^.K ing the inclination of the mast. The control member is f' ed ergonomically so that it may be gripped from above an' t ks adapted to the whole hand. The additionally mounted electrical switches may be operated by the thumb or the 2 index finger whilst the hand contacts the control member or grasps this.

It is the object of the invention to provide a hand actuated control device for the operating condition or situation of a displacing mast lift truck in which the individual functions although actuated from separate operating levers at the same time there is formed an ergonomically operable operating unit.

According to the present invention, a hand actuated control device for the operating condition or situation of a displacing mast lift truck comprises:

three operating levers which are mounted on a common, approximately horizontal axis and which are to be arranged next to one another in the travelling direction of the lift truck; each of the levers including a lever head which can be grasped and actuated essentially by placing on a hand from above as well as a lever section which is located thereunder with the lever sections sitting on a common shaft; the lower ends of the lever sections being coupled to hydraulic valves in a manner such that an inner operating lever lying nearest the driver effects the lifting and lowering of the load carrying means, the middle lever effects the displacing or inclining of the mast and an outer lever effects the inclining or displacing of the mast; and the lever heads, when observed from above, lie on an arcuate line in a manner such that, on changing the grasping of a head, an elbow supported on an underlay can substantially keep its position.

In other words, with the control device according to the invention there are provided three operating levers which are arranged on a common axis this being next to one another transversely to the travelling direction of the truck. The operating levers have a lever head which is formed such that it can essentially be gripped from above 3 for pivoting about the common axis which runs approximately horizontally in the travelling direction.

The lever sections are coupled to the corresponding hydraulic valves via a suitable rod assembly wherein the rod assembly may engage on the operating lever on the side lying opposite the axis. The arrangement of the operating levers is such that the inner, thus the lever lying closest to the driver is used for lifting and lowering the load carrying means, the middle operating lever for displacing the mast and the outer for inclining the mast. It is however also conceivable to reverse the functions of the middle and the outer operating lever.

The heads of the operating levers, observed from above, lie on an arcuate line in a manner such that on gripping over from one lever head to the other from above an elbow supported on an underlay essentially keeps its position. It only requires a certain turning about the support point of the elbow in order to reach from one lever head to the other. A lifting up of the arm is not required for this. From this there results an extremely comfortable manipulation with a minimum of feelings of tiredness.

Due to the function, the inner operating lever automatically forms the lever which is operated the most. This lever according to one formation of the invention has the largest surface, wherein the largest extension of the surface takes place in the direction of the arrangement of the lever heads. A widening of the surface transversely to this is excluded for ergonomic reasons.

The lever sections may be arranged very close next to one another on a shaft or on an axis. In this case it is useful only to let the middle operating lever extend approximately vertically whilst the inner and outer levers with the section lying below the head may be inclined away from the middle operating lever.

The contour of the middle lever observed from above is approximately square or rhombic with heavily rounded corners. The contour of the head of the outer operating 4 lever is somewhat necked on both sides in the region lying to the middle lever in order to simplify a grasping from above. The differing head contour furthermore has the advantage that the driver may ensure by way of merely touching, which operating lever he has grasped.

Since with a displacing mast lift truck further functions are to be operated, specifically the travelling direction instruction and lateral displacement for the load carrying means, one formation of the invention provides that the head of the inner operating lever on the outer side lying opposite the middle operating lever mounts an intermediate switch which can be operated by the thumb when the hand holds the lever head or rests on this, wherein the intermediate switch on pivoting about an axis instructs the travelling direction of the truck and on pivoting about an axis standing perpendicular to this effects the lateral displacement of the load carrying means. An example for the shape of an operating element for such an intermediate switch is described in detail in German Gbm 94 17 838. Here the pivoting of the intermediate switch knob about an approximately horizontal axis causes an instruction of direction whilst a pivoting perpendicularly thereto effects the lateral displacement of the load carrying means.

The intermediate switch and where appropriate a horn key below the intermediate switch on the inner operating lever act electrically. The corresponding switch components are accommodated in the inside of the operating lever or the operating lever cladding. This may be formed as two shells so that the guiding through for the cables lies in the separating plane. By removing one shell section which for example may be fastened to the other by screws, the cables and the components may be laid free and by way of this are accessible without further ado.

The lever surface which may be formed by a suitable plastics coating is generous and ball-like. It snuggles up to the inner surface of the hand. The lever which is used the most has, as mentioned, the largest surface. The horn and travelling directions switches are integrated into that operating lever which is used the most. The levers on account of their shaping act as a complete operating unit.

The invention is hereinafter described in more detail by way of example only with reference to the accompanying drawings wherein:- Fig. 1 shows a front side of a control device according to the invention; Fig. 2 shows the control device in the direction of the arrow 2 in Fig. 1; and Fig. 3 shows a plan view of the control device in a reverse sequence of the operating levers to that shown in Fig. 1.

The control device which is illustrated in an extremely schematic manner in Fig. 1 comprises three operating levers 10, 12 and 14.

The operating levers 10 to 14 are arranged next to one another in a row wherein the row runs approximately in the travelling direction of a displacing mast lift truck (not shown) and the operating lever 10 is that one which is closest to the driver. The actuation of the operating levers 10 to 14 is consequently effected by the right hand of the driver wherein the lower arm or the elbow may be supported on a surface (not shown) lying in front of the levers 10 to 14.

The operating levers 10 to 14 respectively comprise a head 16, 18 and 20. The contour of the heads 16 to 20 observed from above is as shown in Fig. 3. Accordingly the upper side of the head 16 is slightly elongate with heavily rounded corners whilst the upper side or surface of the head 18 is approximately quadratic or rhombic with heavily rounded corners. The upper side of the head 20 is necked towards the middle lever 12 as is indicated at 22 or 24. As is deduced from Fig. 1 and Fig. 2 the heads 16 to 20 are heavily rounded and provided with a relatively large surface so that they may be grasped well from above and by way of this actuated. They comprise on all sides a rounding 6 so that they can snuggle up to the inner surface of the hand.

Lever sections 24, 26 and 28 are mounted on a common shaft 30 which is arranged approximately horizontally in the travelling direction. As proceeds from the lower section of the lever 14, shown in section, the lower lever arm comprises a hole 32 or an eyelet into which a rod assembly may be hung for operating a hydraulic valve (not shown). This similarly applies to the other levers 10 and 12.

As is deduced from Fig. 1 the middle lever 12 extends approximately vertically whilst the lever 10 below the head 16 is bent away from the middle lever. The same applies for the section 28 of the lever 14. By way of this the lower lever sections lie relatively close together whilst at the upper end they have a distance which ensures that on gripping one of the levers the others are not unintentionally co-actuated.

The inner lever 10 serves for actuating the lifting and lowering of a load carrying means. The middle one serves for displacing the mast of the displacing mast lift truck. The outer lever 14 serves for inclining the mast. Consequently the lever 10 which at the same time has the largest gripping surface serves for actuating the function which is applied most frequently.

on the lever sections 24 to 28 respective arcuate covering sections 34, 36, 38 are mounted which cover the gap for the lever on upwards actuation but which for the functioning are of no importance.

As one deduces from Fig. 3 a line 40 connecting the centres of the heads 16 to 18 is arcuate, this being in a manner such that on changing the gripping of one lever the arm or the hand may pivot without the elbow having to be lifted from the underlay and displaced on this.

on the side of the lever 10 lying opposite to the middle lever 18, there is indicated an intermediate switch 42. It serves for instructing the travelling direction by 7 pivoting about the one axis and for the lateral displacement of the load carrying means on pivoting in the opposite direction. The intermediate switch may be actuated with the thumb whilst the hand rests on the head 16 or grips this. An actuation in the direction of the double arrow 44 is e.g. the travelling direction instruction. An actuation perpendicular to this actuates the lateral displacement of the load carrying means. It is to be understood that also other switching means are conceivable.

Below the intermediate switch 42 a horn key 46 is provided in the lever 10.

The cables and components belonging to the operating elements 42, 46 are integrated into the lever 10. This or its covering is usefully designed as two parts as is indicated by the dashed line 48. In this way there are formed two sections of which the one can be removed in order to lay free the cables and components. In Fig. 1 this is the right part of the lever 10 which can be unscrewed. The leading through for the cables takes place in the separating plane 48.

8 claims 1. A hand actuated control device for the operating condition or situation of a displacing mast lift truck comprising:

three operating levers which are mounted on a common, approximately horizontal axis and which are to be arranged next to one another in the travelling direction of the lift truck; each of the levers including a lever head which can be grasped and actuated essentially by placing on a hand from above as well as a lever section which is located thereunder with the lever sections sitting on a common shaft; the lower ends of the lever sections being coupled to hydraulic valves in a manner such that an inner operating lever lying nearest the driver effects the lifting and lowering of the load carrying means, the middle lever effects the displacing or inclining of the mast and an outer lever effects theinclining or displacing of the mast; and the lever heads, when observed from above, lie on an arcuate line in a manner such that, on changing the grasping of a head, an elbow supported on an underlay can substantially keep its position.

2. A control device according to claim 1, in which the inner lever head has the largest surface.

3. A control device according to claim 2, in which the surface enlargement extends substantially in the direction of the arrangement of the operating levers.

4. A control device according to any preceding claim, in which the inner operating lever below its head is inclined away from the middle operating lever in the plane of the operating levers. 1 9 5. A control device according to any preceding claim, in which the axis of the middle operating lever is approximately vertical.

6. A control device according to any preceding claim, in which the outer operating lever below its head is inclined away from the middle operating lever in the direction of the arrangement of the operating levers.

7. A control device according to any preceding claim, in which the contour of the head of the inner operating lever observed from above is slightly elongate in the direction of the other levers.

is 8. A control device according to any preceding claim, in which the contour of the head of the middle operating lever observed from above is approximately square or rhombic with rounded corners.

9. A control device according to any preceding claim, in which the contour of the head of the outer operating lever observed from above comprises a section necked towards the middle operating lever.

10. A control device according to any preceding claim, in which the head of the inner operating lever on the side opposite to the middle operating lever mounts an intermediate switch which can be actuated by the thumb when the hand holds said head or contacts said head.

A control device according to claim 10, in which the intermediate switch on pivoting about one axis instructs the travelling direction of the lift truck and on pivoting about the axis perpendicular to this effects a lateral displacement of the load carrying means.

12. A control device according to claim 10 or claim 11, in which below the intermediate switch there is arranged a horn key.

13. A control device according to any one of claims 10 to 12, in which cladding of the head of the inner operating lever consists of two shells, wherein the leading through of a cable for the components of the intermediate switch and/or of the horn key runs in the separating plane of the shells and thus the components are disassemblable.

14. A control device substantially as hereinbefore described with reference to the accompanying drawings.