DUAL CONTROL FOR VEHICULAR CRANES

Abstract: A dual control for vehicular cranes comprises two separate control units with control levers cooperating in pairs, which levers are protected by casings (7, 7') consisting of pivotable shell parts (9, 9') which in a closed position enclose and protect the control levers and in an open position expose the levers. In the two casings (7, 7') are arranged analogous locking mechanisms (14, 14') which comprise locking means (15, 15') being movable between locking and releasing positions. The two locking mechanisms are coupled to a transmission (18) which in a neutral position permits that the one casing (7') is opened and that in connection therewith transfers the opening motion of the movable shell part (9) to the locking mechanism of the other casing (7) in order to secure its locking means (15) in the locking position and, thereby, make the opening of the other casing (7) impossible as soon as the first one (7') is opened.

Description: DUAL CONTROL FOR VEHICULAR CRANES Technical Field of the Invention This invention relates to a dual control for vehicular cranes, comprising two control units that are placeable on opposite longitudinal sides of a vehicle and that either comprise a plurality of manually actuatable control elements, for instance levers, which cooperate in pairs insofar as the individual control element in the one unit is connected with a corresponding control element in the other unit, in order to make possible an activation of a common operating means, inde¬ pendently of whether the one or the other element in a pair of elements is actuated manually, each control unit comprising a casing arranged to protect the control elements, the casing having a shell-shaped part that is movable between a closed position in which the control elements are enclosed and protec¬ ted, and an open position in which they are accessible from outside . Prior Ar Dual controls of the type as defined in the introduc¬ tion are previously disclosed in, e.g., SE 8201833-4. Further, by prior use it is known to equip the two control units with protective casings consisting of two inter-pivotably movable, shell-shaped parts which in a closed position enclose and protect the control elements, while they in an open position permit the access to the control elements. Moreover, WO 95/16630 discloses a protective casing in the form of a simple cover that is pivotable between closing and opening positions. A drawback in connection with dual controls of the type referred to, is that they theoretically permit a simultaneous actuation by both control units. If the permanent crane opera¬ tor, normally the vehicle driver, actuates an individual control element in one of the control units, for instance on the driver's side of the vehicle, it is possible for another person to intentionally or unintentionally actuate another control element in the other control unit, on the opposite longitudinal side of the vehicle. This implies that the crane could be subjected to motions that are not at all intended to be executed by the permanent crane operator. For instance, said operator could actuate a control element for only lowering the crane beam and a load hanging on it, at the same time as somebody not directly concerned actuates an element comprised m the opposite control unit, which element makes the crane beam pivot late¬ rally. In practice, such a situation may of course have disast¬ rous consequences, for the load object as well as the environ- ment . Ob ects and Features of the Invention The present invention aims at eliminating the above mentioned safety risk related to previously known dual commands and create the conditions for a reliable control of the diffe¬ rent functions of the crane. Therefore, a basic object of the invention s to further develop the protective casings known per se for the two control units of the dual command to such an extent that a simultaneous actuation of individual control elements in the units is rendered impossible. One object is also to bring about this increased safety by means of simple, mecha¬ nical means which are not dependent on the supply of electricity or hydraulic oil. According to the invention, at least the basic object is attained by the features as defined in the characterizing clause of claim 1. Advantageous embodiments of the invention are further defined m the dependent claims. Brief Description of the Appended Drawings In the drawings: Fig 1 is a perspective view of a vehicular crane with a dual command, whose two control units are built into protec¬ tive casings, Fig 2 is a partial, enlarged perspective view showing the protective casing of the one control unit, in an open state, Fig 3 is a schematic view of a first embodiment of the inven¬ tion, each one of the two protective casings of the control units being shown in a closed state, Fig 4 is a corresponding view showing one of the protective casings in an open state, at the same time as the other protective casing is closed, Fig 5 is a view corresponding to fig 3, showing a second, alternative embodiment of the invention, Fig 6 is a view showing the same embodiment as in fig 5, but with the one protective casing open, Fig 7 is an enlarged detail view in fig 6, Fig 8 is a view corresponding to fig 3 and 5, showing a third, alternative embodiment of the invention, both protective casings being shown in a closed state, Fig 9 is a view showing the one protective casing according to fig 8 in an open state, at the same time as the other protective casing is closed. Detailed Description of Preferred Embodiments of the Invention In fig 1, reference numeral 1 designates generally a crane that is mounted on a carrier 2. The crane comprises a post 3, a lifting beam 4 and a jib lever 5. For the control of the different functions of the crane, a dual control is provided comprising two control units 6, 6' , each one of which comprising a number of control elements, which are built into the protec¬ tive casings 7 and 7' , respectively. As may be seen in fig 2, each control unit in the example comprises six control elements 8 in the form of levers, and the protective casing 7 is assemb¬ led of two shell-shaped parts 9, 9' , which are pivotably movable between the closed position as shown in fig 1 and the open position as shown in fig 2. More specifically, the two shell parts 9, 9' are at their inner ends interconnected via gear rim segments 10 which attend to that the shell parts are simul¬ taneously forcedly pivoted around appurtenant leading bars 11, 11' . The control levers 8 in the one unit 6 are connected with the corresponding levers in the other unit 6 ' , preferably via cross-laid bars 12. Each cooperating pair of levers in the two units may actuate a common operating means in the form of a hydraulic valve that determines a desired crane function. In this way, each hydraulic valve may be activated by either of the two levers in the units 6, 6' which jointly form a cooperating pair. In other words, the operator may activate a desired crane function independently of on which side of the vehicle he is placed. In fig 1 and 2 a handle 13 is shown, by means of which the two shell parts of the individual protective casing may be closed and opened, respectively. As far as the described dual control has been hitherto described, it is previously known from SE 8201833-4 and by prior use. Reference is now made to fig 3 and 4, which show a first embodiment of the present invention. In each protective casing, there is arranged a locking mechanism, in its entirety designated by 14 and 14 ' , respectively, said locking means comprising a locking means 15 and 15', respectively, being • movable between a locking and a releasing position. Each such locking means cooperates with two wedge-shapedly tapering stop shoulders 16, 17 on the inside of the individual shell parts 9, 9' . Between the locking means 15, 15' extends a transmission in the form of a bar or rod 18, which at opposed ends is connected to links 20 via joints 19, the locking means 15, 15' being attached to the free ends of said links. A finger 21 is stiffly connected to each lower shell part 9, which finger is connected to the one end of a draw spring 22, whose opposed end is connec¬ ted to an attachment 23 in the form of a sleeve applied on the bar 18. Advantageously, this sleeve may be movable along the bar and adjustable into different positions relative to it by means of a set screw (not shown) . In fig 3, the transmission bar 18 is in a neutral position in which the two locking means 15, 15' are distanced from the appurtenant pair of stop shoulders 16, 17. This implies that the two shell parts 9, 9' in their respective protective casings are free to be opened without any obstruction by the locking means 15, 15' . However, if one of the protective casings, e.g. casing 7' , is opened in the way as shown in fig 4, viz . by the shell parts 9, 9' being pivoted out from each other, then the transmission bar 18 will be set in motion in the direc- tion of arrow A. When the lower shell part 9 is pivoted down, then the finger 21 serving as a carrier will tension the two draw springs 19, the left spring making the bar 18 move to the left; something having the consequence of the locking means 15 being brought into engagement with the two stop shoulders 16, 17. This implies that the locking means 15, in cooperation with the shoulders 16, 17, locks the two shell parts 9, 9' of the casing 7 relative to each other, as soon as the shell parts 9, 9' in the other casing 7' have been opened. In other terms, an actuation of the control levers 8 that are within the casing 7 when the control levers 8 in the opposed protective casing 7 ' are exposed and accessible to manual actuation, is made impossible. When the shell parts of the casing 7' are closed again by pivoting them towards each other, then the right draw spring 22 guarantees that the transmission bar 18 returns to the neut¬ ral position according to fig 3. In fig 5-7 an alternative embodiment is shown, accor¬ ding to which the individual locking means 24 has the shape of a pivotable clutch that is connected with a shaft 25 which in turn is co-rotatively connected with the previously mentioned handle 13 (see fig 1 and 2) . In the example, the handle and the locking clutch 24 are mounted on the lower shell part 9 in each protec¬ tive casing, the clutch 24 cooperating with a stop dowel 26 on the inside of the upper shell part 9 ' . In the region below each locking clutch 24 is arranged a detent element 27 in the form of an elastic, bendable plate spring. More specifically, the plate spring 27 is L-shaped and has its lower flange 27' attached to the shell part 9. An upstanding upper flange 27" is connected with a transmission element in the form of a wire 28 that extends between the two protective casings 7, 7' , suitably accomodated in an encircling tube 29. In fig 5 the transmission wire 28 is shown in a neutral position, in which the two detent elements 27 are distanced from the appurtenant locking clutches 24, so that these may be pivoted without any obstruction by the detent elements. In this state, the two protective casings are closed and the locking clutches 24 are engaged with the appurtenant stop dowel 26. When one of the two protective casings (in the example, the casing 7') is to be opened, the handle 13 on the shell part 9 in question is turned, whereby the locking clutch 24 is relea- sed from the stop dowel 26. Then the two shell parts 9, 9' may be pivoted out relative to each other in the way as shown in fig 6. By the pivoting motion of the lower shell part 9, the wire 28 is set in motion in the direction of arrow B in fig 6 and the upstanding bendable flange 27' of the detent element 27 in the casing 7 is bent in such a way that it is inserted underneath the locking clutch 24. As a consequence thereof, a pivoting of the locking clutch 24 is rendered impossible; something that in turn brings about that the two shell halves 9, 9' of the shell 7 cannot be pivoted out and opened. When the protective casing 7' is closed again, the transmission wire 28 automatically returns to the neutral position that is shown in fig 3, by the fact that the elastic plate springs forming the detent elements 27 take the unloaded starting position in which they are distanced from the locking clutches 24. In fig 8 and 9 is shown a third, alternative embodiment which is substantially similar to the embodiment according to fig 5 to 7. However, instead of one single transmission wire, two separate wires 28' , 28" are used here, which suitably are led through separate tubes 29' and 29", respectively. The one end of each transmission wire is still attached to a plate spring 27 serving as a detent element for a locking clutch 24, but the opposed end of the wire is attached to a special attachment 30 on the inside of the lower shell part of the opposite protective casing. The advantages of the invention are evident. By the simple mechanical transmission and the locking mechanisms cooperating therewith in the two protective casings, an automa¬ tic locking is guaranteed by one of the protective casings as soon as the other one is opened. The locking of the non-opened protective casing makes it impossible for any other one than the crane operator himself to intentionally or unintentionally activate any of the functions of the crane. Feasible Modifications of the Invention The invention is not restricted solely to the embodi- ments as described and shown in the drawings. Thus, it is feasible to apply the invention also on protective casings which comprise one sole movable shell part, e.g., a shell part of the type as shown in WO 95/16630. It is also feasible to apply the invention in connection with protective casings, whose shell part or parts are movable in another way than by pivoting, e.g., by displacement.

Claims: Claims 1. A dual control for vehicular cranes, comprising two control units (6, 6') that are placeable on opposite longitudinal sides of a vehicle and that either comprise a plurality of manually actuatable control elements, for instance levers, which coope¬ rate in pairs to that extent that the individual control element in the one unit (6) is connected with a corresponding control element in the other unit (6') , in order to make possible an activation of a common operating means, independently of whether the one or the other element in a pair of elements is actuated manually, each control unit comprising a casing (7, 7') arranged to protect the control elements (8), the casing having a shell- shaped part (9, 9') that is movable between a closed position in which the control elements are enclosed and protected, and an open position in which they are accessible from outside, c h a r a c t e r i z e d in that analogous locking mechanisms (14, 14') are arranged in the two protective casings (7, 7') , each of which mechanisms comprising a locking means (15, 15' ; 24) that is movable between locking and releasing positions, and which mechanisms are coupled to at least one transmission (18; 29, 29' , 29") which in a neutral position permits that one of the casings (7') is opened and which in connection herewith trans¬ fers the opening motion of the movable shell part to the locking mechanism of the other casing (7) , in order to secure its locking means (15, 15' ; 24) in the locking position and thereby make it impossible to open the other casing (7) as soon as the first one (7') is opened. 2. Dual control according to claim 1, c h a r a c t e r i z e d in that the transmission comprises a bar (18) which is held in said neutral position by means of springs (19) and which in the region of opposed ends has locking means (15, 15') that are distanced from fixed stop shoulders (16, 17) to said shell parts (9, 9') as long as the transmission bar is in the neutral position, the bar during opening of the one casing (7') being brought to distance itself from the other casing (7) , to thereby engage and lock at least one stop shoulder (16, 17) comprised in this casing. 3. Dual control according to claim 2, c h a r a c t e r i z e d in that the individual locking means (15, 15') is mounted on a free end of a link (20) that is articulatedly connected with the bar (18) itself. 4. Dual control according to claim 1, c h a r a c t e r i z e d in that the locking means (24) cooperate with detent elements (27) which in the neutral position of the transmission (28) are distanced from the locking means to permit one of those to move from a locking to an opening position, and that the transmission is arranged to transfer the opening motion of the shell part of the one casing to the detent element in the other casing, in order to detend the appurtenant locking means in the locking position. 5. Dual control according to claim 4, c h a r a c t e r i z e d in that the detent element has the shape of an elastic, bendable plate spring (27) which in an unloaded state is distanced from the locking means (24) and in a state actuated by the transmis¬ sion may be bent into a position engaging underneath the locking means, in which position the locking means is detended. 6. Dual control according to claim 5, c h a r a c t e r i z e d in that the transmission has the form of a wire or similar (28) that extends between the bendable plate springs (27) . 7. Dual control according to claim 5, c h a r a c t e r i z e d in that the transmission comprises two wires (28' , 28") , either of which being attached by its one end to the movable shell part (9) of the one casing, and by its opposite end to the detent element (27) of the other casing. Dual control according to any of claims 4 to 7, c h a r a c t e r i z e d in that the locking means has the form of a pivotable clutch (24) which in its locking position is engaged with a fixed stop element (26) .

Inventors: NORDLOEF JONAS, SALAAKER ALLAN, NORDLOEF, JONAS, SALAAKER, ALLAN
Applicants: HIAB AB, NORDLOEF JONAS, SALAAKER ALLAN, NORDLOEF, JONAS, SALAAKER, ALLAN
Application year: 1997
Main classification: B66C13
IPC codes: G05G1, G05G5, G05G13