° A device in an expandable and' contractable arm

FIELD OF THE INVENTION AND PRIOR ART

This invention is related to a device in an expandable and contract- 0 ible arm. The arm is intended to function as a carrier for a slide movable along the arm. A particularly preferred field of use of the invention is transfer of load units between two carriers, the arm being intended to extend between said carriers and the slide being conceived to carry a load unit under displacement of the slide along 5 the arm from one carrier to the other.

Prior devices of the above indicated nature have suffered from the disadvantage that they have been rather complicated and as a con¬ sequence thereof bulky and heavy. It is in this connection pointed 0 out that a slim and light weight design of the arm and the carrier movable thereon is desirable.

SUMMARY OF THE INVENTION

5 The object of the invention is to develop the prior art according to the pre-characterizing part of the enclosed claims 1 , 6 and 13 for the purpose of providing devices which unite a relatively low de¬ gree of complication and, accordingly, a low cost with a relatively low weight and excellent operability. 0

This object is according to the invention achieved by providing the device with the features recited in the enclosed claims, and in par¬ ticular in the characterizing parts in claims 1 , 6 and 13.

5 As far as claim 1 is concerned, the solution defined means that the expansion and contraction of the arm may occur in a simple way by

means of the two traction force transmitting elements and the drums driving the same.

The design of the expandable and contractible arm in accordance with claim 6 gives rise to a substantially planar running surface for the slide at the same time as an excellent mutual guiding of the arm parts is maintained.

The driving arrangement for the slide defined in claim 13 involves, finally, that the slide is operable reciprocatingly in an efficient man¬ ner along the arm.

Further preferable designs according to the invention are discussed hereunder and defined in dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the enclosed drawings, a more specific descrip¬ tion of an embodiment example of the invention follows hereunder. In the drawings:

Fig. 1 is a diagrammatical view illustrating the arm according to the invention applied for transfer of load units between car¬ riers;

Fig. 2 is a diagrammatical view of the arm according to the inven¬ tion as viewed from above, the extent of the traction force transmitting elements being illustrated with dashed lines,

Fig. 3 is a perspective view illustrating a base part contained in the arm;

Fig. 4 is a cross-section through one half of the arm according to the invention with a slide placed thereon;

Fig. 5 is a diagrammatical view illustrating an arrangement for driving the slide along the arm;

Fig. 6 is a diagrammatical view from above illustrating drums for operating the traction force transmitting elements for dis¬ placement of the slide;

Fig. 7 is a view similar to Fig. 5 but illustrating the arm contracted and the slide in a position above the contracted arm, and

Fig. 8 is a diagrammatical view of the arm according to the inven¬ tion viewed from above.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The device according to the invention will hereinafter be described as used in an apparatus for transferring load units between two carriers. However, it is pointed out that the device according to the invention may have other uses. Two carriers illustrated in Fig. 1 are denoted 1 and 2 respectively. A first 1 of the carriers comprises a transfer arrangement 3 having at least one arm 4, which is expand¬ able and contractible respectively with regard to length in the transverse direction of the carrier 1 and which forms a path of movement for a carrying member 5 included in the transfer ar- rangement 3, said carrying member 5 being guidedly movable along the arm 4 and arranged to carry a load unit 6 intended to be displaced.

The arm 4 forms a construction rigid against deflection downwardly and intended to be placed so as to rest on the longitudinal centre line of the carrier 2, possibly with interposition of load applying means 7, the purpose of which is to evenly apply the load on the carrier 2 and which also could have the purpose to elevate and lower the outer end of the arm 4 so as to achieve a suitable trans- fer position.

The arm 4 comprises a base part 8, which is attached to the carrier 1 and which rests, by means of suitable intermediate means 9,10, on the chassis of the carrier 1. Said means 9, 10 may be designed to simply apply the load from the base part 8 in an adequate man- ner on the carrier 1 but could also have the purpose to adjust the position of the base part 8 relative to the carrier 1. As an example, the centrally located means 9 could be intended to raise and lower the position of the base part 8 relative to the carrier 1 , whereas the means 10 located externally thereof, i.e. at the sides of the carrier 1 , could have the purpose to adjust a desired inclination of the arm 4 so that a load unit 6 may be transferred along the arm with assis¬ tance of gravitation.

As indicated in Fig. 1 , the carrier 1 may comprise a base chassis 11 and a frame 12, which is elevatable and lowerable in relation to the base chassis by means of power members 13 and which is designed to support the base part 8 via the means 9, 10.

On transfer of the load unit 6 to the carrier 2, the slide 5 is intended to slide on the arm 4 until the load unit and the slide are located centrally on the carrier 2, whereupon the slide 5 is relieved from load and returned to the carrier 1 and the arm 4 is contracted back to the carrier 1. Relieving of the slide 5 may for instance occur by the slide comprising lifting means, which on the carrier 2 lowers the load unit 6 into contact with suitable support elements or alterna¬ tively the carrier 2 may comprise lifting members capable of lifting the load unit 6 out of engagement with the slide 5 so that the same is relieved and may return to the carrier 1.

In Fig. 1 the carriers 1 , 2 are illustrated as consisting of vehicles, more specifically a railway car and a road vehicle respectively. Of course, one of the carriers 1 , 2 could consist of a stationary carry¬ ing arrangement and also other types of vehicles may be in ques¬ tion. In Fig. 2 it is illustrated in a diagrammatical view from above that the arm 4 comprises the base part 8, an outer part 14 and two intermediate parts 15, 16. As will be described more closely with

the assistance of Fig. 4, each arm part comprises two mutually connected portions separated in the transverse direction of the arm. These portions are denoted 17 as far as the base part 8 is concerned, 18 as far as the outer part 14 is concerned, 19 as far as the intermediate part 15 is concerned and 20 as far as the inter¬ mediate part 16 is concerned.

The device comprises, as appears from Fig. 2, two traction force transmitting flexible elements 21 , 22, which both are rigidly con- nected, by means of first ends 23 and 24 respectively, to the outer part 14 and which are intended to be connected, by means of sec¬ ond ends indicated at 25 and 26 respectively in Fig. 2, to drums 27, 28, which preferably are driven by a motor 29, for drawing in and feeding out respectively of the elements 21 , 22.

The device comprises two sets of first and second traction force transmitting elements 21 , 22, said sets being arranged as mirror images of each other on either sides of a longitudinal centre plane M through the arm. The two elements 21 , 22 in each set are ar- ranged above each other. However, in Fig. 2 there is illustrated on one side of the centre plane M a traction force transmitting element 21 for expansion of the arm and on the other side of the centre plane an element 22 for contraction of the arm. It should be under¬ stood that there is, in a complementary manner, on each side of the centre plane a further element for contraction of the arm in con¬ junction with the element 21 and an element for expansion of the arm in conjunction with the element 22.

As further appears from Fig. 2, the traction force transmitting ele- ments 21 , 22 and diverting members therefor are located within the various portions 17, 18, 19, 20 of the parts.

In Fig. 3 it is illustrated that the end portion 25 of the element 21 engages with the drum 27 whereas the end portion 26 of the ele- ment 22 engages with the drum 28. The drum 27, 28 is in the ex¬ ample located under the arm portion 17 and the elements 21 , 22

are diverted downwardly to the drum by means of diverting mem¬ bers 30.

The element 21 for expansion of the arm 4 extends about a first di- verting member 31 arranged at that end of the base part 8 which is turned in the direction of expansion indicated with the arrow 32. The element 21 is arranged to apply an expansion force on the outer part 14 at a point 33 located at that end of the outer part 14 which is turned in the direction of contraction. The first element 21 runs, as far as each occurring intermediate part 15, 16 is con¬ cerned, via second and third diverting members 34, 35 arranged on the intermediate part 15, 16 in question. Of these diverting mem¬ bers, the second 34 is arranged at that end of the intermediate part 15, 16 which is turned in the direction of contraction opposite to the arrow 32, whereas the third 35 is arranged at that end of the inter¬ mediate part 15, 16 which is turned in the direction of expansion.

The element 21 runs, from the diverting member 35 arranged at that end of the intermediate part 15, 16 which is turned in the di- rection of expansion, in the direction of contraction opposite to the arrow 32 to the outer part 14 or a further intermediate part, whereas the element 21 runs, from the third diverting member 34 arranged at that end of the intermediate part 15, 16 which is turned in the di¬ rection of contraction, in the direction of expansion to the first di- verting member 31 of the base part or a second diverting member 35 of a further intermediate part.

The second element 22 arranged for contraction of the arm 4 ex¬ tends about a fourth diverting member 36 arranged at that end of the base part 8 which is turned in the direction of contraction. The second element is arranged to apply a force of contraction on the outer part 14 at a point 37 located at that end of the outer part 14 which is turned in the direction of expansion. The element 22 runs, as far as each occurring intermediate part 15, 16 is concerned, via fifth 38 and sixth 39 diverting members arranged on the intermedi¬ ate part, the fifth 38 of which is arranged at that end of the inter-

mediate part 15,16 which is turned in the direction of expansion, whereas the sixth 39 is arranged at that end of the intermediate part which is turned in the direction of contraction, the element 22 running, from the sixth diverting member 39 arranged at that end of the intermediate part which is turned in the direction of contraction, in the direction of expansion to the outer part or to further interme¬ diate part 16, whereas the element 22 runs, from the fifth diverting member 38 located at that end of the intermediate part 15, 16 which is turned in the direction 32 of expansion, in the direction of contraction to the fourth diverting member 36 of the base part or a sixth diverting member 39 of a further intermediate part 15.

It is illustrated in Fig. 3 how drums 27, 28 present for a set of two traction force transmitting elements 21 , 22 are arranged synchro- nously driven, e.g. by means of one and the same motor 29, such that when one of the drums draws in the first element 21 the outer drum feeds out the second element and vice versa. The two drums 27, 28 are connected to each other. They may be designed as one single component comprising two compartments for the two ele- ments and they are suitably mounted on the same axle or part holding them together.

As far as the device has been described so far, it can be expanded in the direction of arrow 32 by rotating the drum set 27, 28 counter clockwise as illustrated in Fig. 3. This means that a traction force will be exerted in the element 21 , which in turn means that the arm parts 14, 15, 16 will be extended to the right in Fig. 2 according to the arrow 32. At the same time the traction force transmitting ele¬ ment will be fed out from the drum 28, such that the element 22 will not form a hindrance.

On rotation of the drums 28, 27 in the opposite direction, the arm 4 will be contracted in the direction opposite to the arrow 32 in that a traction force will be established in the element 22 at the same time as the element 21 is fed out from the drum 27 such that the element 21 will not function as a hindrance.

The arm 4 is expandable in diametrically opposite directions, the first traction force transmitting element 21 as well as the associated diverting members, which in accordance with that which has just been described may operate to expand the arm 4 in the direction 32, also are arranged to carry out contraction of the arm in the same direction from a state where the arm 4 has been extended in the direction of arrow 40. The second traction force transmitting element 22 is arranged to carry out expansion of the arm 4 in this second direction 40.

On contraction of the arm 4 starting from an expanded position, it may be desirable to make certain that the extended parts 14, 15 and 16 are located directly opposite to the base part 17. For this purpose a stop member 41 diagrammatically illustrated in Fig. 2 could be used. On, for example contraction of the arm 4 from the position according to Fig. 2, the stop member 41 should be ar¬ ranged to stop the various arm parts 14, 15, 16 in the position op¬ posite to the base part 17. Thereafter the stop member 41 should suitably be retracted so that for instance expansion of the arm in the direction of arrow 40 may occur without hindrance. A further stop member is suitably arranged in a corresponding manner as the stop member 41 to serve as a stop on contraction of the arm start¬ ing from a state expanded in the direction of the arrow 40.

The points 33, 37 discussed with aid of Fig. 2 are in the example formed by diverting members located, as viewed in the direction 32 of expansion, at the inner and outer ends respectively of the por¬ tions 18 of the outer part 14. From these points 33, 37 the elements 21 , 24 run to the attachment points 23, 24 relative to the outer part portions 18.

In Fig. 4 there is illustrated in cross-section a part of the arm 4, namely its portions 17, 18, 19 and 20. It is pointed out that only the portions 17-20 located on one side of the middle plane M illustrated in Fig. 2 appear in Fig. 4.

As seen in Fig. 4, the portions 17-20 form in unison an upper sur¬ face 42, which is substantially planar in the longitudinal direction as well as the transverse direction of the arm 4. The slide 5 is in- tended to slide on this planar surface 42. In order to reduce friction, it is suitable that the surface 42 and/or the lower surface of the slide 5 comprises a low friction coating, for instance of TEFLON. However, it is pointed out that the slide 5 also could contact the upper side 42 of the arm 4 indirectly via wheels, balls or other run- ning elements.

The arm part portions 17-20 engage in a guiding manner with each other via projections 43 and recesses 44 designed on such adja¬ cent edges of the portions 17-20 which are orientated at an angle, in particular a substantially right angle, to the planar surface 42. Expressed in other words, the projections 43 and recesses 44 are, accordingly, provided on upstanding sides of the portions 17-20. The projections 43 and recesses 44 engage in a guiding manner with each other such that the arm 4 in its entirety functions to with- stand load vertically or, in another orientation of the arm 4 than horizontal, substantially perpendicularly to the planar surface 42. The projections 43 and recesses 44 are in such a hooking engage¬ ment with each other that the portions 17-20 are prevented from separating from each other in a direction substantially parallel to the planar surface 42. As seen from Fig. 4, this is in reality achieved by the projections 43 and recesses 44 having a T-like shape in cross-section. It is then disregarded that each individual projection 43 in reality is formed by two projection portions 45 mu¬ tually separated at an angle to the planar surface 42.

The arm part portions 17-20 are hollow and adapted to internally house traction force transmitting elements 21 , 22 and diverting members, for instance 36, 31 , therefor serving for expansion and contraction of the arm 4. The elements 21 , 22 and diverting mem- bers are received between the projection portions 45.

Between pairs of adjacent portions 17-20 there are provided slit¬ like openings 46, which extend along the arm 4 and form female guide members for engagement with male guide members 47 e.g. in the form of guide strips, provided on the slide 5. It is, however, pointed out that the arrangement also could be inverted in the sense that the female guide members could be provided on the slide 5, whereas the male would be provided on the arm 4. The embodiment illustrated, where the female guide members 46 are provided in the border zone between two adjacent portions 17-20, involves, however, a preferable embodiment in that a space al¬ ready at hand only will have to be dimensioned so as to be capable of receiving the guide member 47 on the slide 5.

In Figs. 5-7 a design of a driving arrangement 48 for the slide 5 is illustrated. This driving arrangement comprises at least two traction force transmitting flexible elements 49, 50. As is most clearly ap¬ parent from Fig. 6. also here the arrangement is doubled on either sides of a longitudinal centre plane M through the arm 4. In the fol¬ lowing the design will be described, however, only on one side of the centre plane M. The elements 49, 50 are rigidly connected, by means of first ends, to the slide 5 at an attachment indicated at 51. The elements 49, 50 are connected, by means of second ends, to first and second drums 52 and 53 respectively, which preferably are driven by motors 54 and 55 respectively, for drawing in and feeding out respectively of the elements. A first 49 of the slide driving elements runs from the first drum 52 in the direction of con¬ traction opposite to the direction 32 of expansion to a first diverting member 56 arranged at that end of the base part 8, which is turned in this direction, and from this first diverting member to the attach- ment point 51 relative to the slide. The second 50 of the slide driv¬ ing elements runs from the second drum 53 to a second diverting member 57 arranged at that end of the outer part 14 which is turned in the direction 32 of expansion and from the second diverting member in the direction of contraction opposite to the arrow 32 to the attachment point 51 relative to the slide 5.

The arm 4 is expandable also in a second direction 40 opposite to the first direction 32. The first slide driving element 49 runs, be¬ tween the diverting member 56 and the slide, via a third diverting member 58, which is arranged at that end of the outer part 14 which is turned in the second direction 40 of expansion. The second slide driving element 50 runs via a fourth diverting member 59 arranged at that end of the base part 8 which is turned in the first direction 32 of expansion. The second slide driving element 50 is in this way ar¬ ranged to carry out driving of the slide 5 in the first direction 32 of expansion of the arm 4, whereas the first slide driving element 49 is arranged to carry out driving of the slide 5 in the second, oppo¬ site direction 40 of expansion of the arm 4.

The drums 52, 53 and the motors 54, 55 driving the same are ar- ranged in a frame supporting the base part 8 under the base part 8 in a manner which is indicated in Fig. 5. The diverting members 56, 59 are co-ordinated with adjacent diverting members 60, 61 ar¬ ranged at the ends of the base part 8 at approximately the same level as the diverting members 56, 69 but more closely to the ends of the base part 8 such that the slide driving elements 49, 50 will run between these two pairs of diverting members 60, 56 and 59, 61 respectively. The purpose of the diverting members 60, 61 is to divert the slide driving element 49, 50 upwardly so that they will run closely under the arm parts 14, 15 and 16.

It is illustrated in Fig. 7 that the arm 4 is entirely contracted and that the slide is present above the base part 8 of the arm 4. The drums 52, 53 have collected the main part of the lengths of the elements 49, 50.

The device illustrated and described with assistance of Figs. 5-7 operates in the following manner.

If the arm 4 is to be expanded in any direction without the slide 5 being caused to follow the arm, the elements 21 and 22 discussed with the assistance of Figs. 2 and 3 are driven in a suitable man-

ner. This means that the outer part 14 of the arm moves in any of the directions indicated by the arrows 32 and 40. Let us assume that the outer part 14 is driven to the right according to Fig. 5. This means that the diverting member 57 arranged on the outer part 14 exerts a traction in the element 49. In order to avoid this traction from causing the slide 5 to move, the drum 53 must be driven by means of the Motor 55, such that it feeds out the element 50. At the same time the second drum 52 should be maintained locked so that it counteracts displacement of the slide 5 in the direction of arrow 32. When the arm 4 has been expanded to a desired degree, the slide 5 may be displaced in a desired extent by driving the drum 53 such that a traction force is exerted in the element 50, which as a consequence of the placement about the diverting member 57 at the outer end of the outer part 14 draws the slide 5 in the direction to the right in Fig. 5 to the end position illustrated there. At the same time the drum 52 should of course be released such that the element 49 is fed out in a required degree. On expansion of the arm 4 in the direction of the arrow 40, the corresponding occurs, the element 49, however, having to be, initially, fed out from the drum 52, in order to maintain the slide 5 stationary on the base part 8 of the arm. When there is a need for displacement of the slide 5 in the direction of arrow 40, the drum 52 is driven such that it ac¬ cumulates the element 49 to the required degree, the element 50 being, at the same time, released by means of the drum 53.

In Fig. 8 it is diagrammatically illustrated in a view from above how the arm 4 may be constructed. The various diverting members 56- 60 for the traction force transmitting elements 49, 50 for displace¬ ment of the slide 5 are also apparent in Fig. 8. It also appears from Fig. 8 how the diverting members are doubled on either sides of the vertical centre plane M of the arm. Fig. 8 also illustrates rollers 62, which are located in the centre plane M and which may be de¬ signed to guide conduits for possible supply of the parts of the arm 4 or the slide 5 with energy, e.g. electrical or pressure fluid based energy, said conduits being neither illustrated nor described in more detail. The guide members 62 could for instance be used for

guiding conduits for supplying pressurised fluid, e.g. pressurised air, to the diagrammatically illustrated means 7. Accordingly, the means 7 comprise one or more cushion or bellow like members for even contact of the outer part of the arm 4 against an underlayer, e.g. the carrier denoted 2 in Fig. 1.

Fig. 8 also illustrates diagrammatically the means 9, 10, which al¬ ready have been described with assistance of Fig. 1 and which also are illustrated as pressurised fluid operated cushions or bellows.

It is preferred that the traction force transmitting elements are formed by lines, whereas the diverting members are formed by pulleys.

It is evident that the devices described may be modified in several ways within the scope of the invention.