POSITIONING APPARATUS

Abstract: The disclosure relates to a positioning apparatus for workpieces whose length is to be adjusted. The apparatus includes a conveyor which advances the workpieces. Beside this feed conveyor, there is an additional conveyor on which adjustable abutment means are mounted. The two conveyors move at the same speed and in the same direction, so that each one of the abutment means, throughout the entire movement, is located in register with one and the same workpiece. A transverse displacement device realises the lateral displacement of the workpieces until such time as the abutment means receive them. The abutment means may be either stepwise or continuoulsy adjustable. For a further stabilisation of the workpieces, there is a rail mounted at the discharge end of the conveyor, so that the end of each workpiece will slide along this rail without being displaced in the transverse direction.

Description: POSITIONING APPARATUS TECHNICAL FIELD The present invention relates to an apparatus for positioning workpieces, such as timber workpieces or profile bars whose length is to be adjusted, and comprises: a feed conveyor by means of which the workpieces are fed with their longitudinal direction substantially at right angles to the direction of feed of the conveyor, transverse displacement devices disposed to displace the workpieces in their longitudinal direction transversely of the direction of feed, and abutment means for arresting the transverse displacement movement of the workpieces, whereby the one end of the workpieces is positioned. BACKGROUND ART Positioning apparatuses of the type intimated by way of introduction are previously known in the art. Such positioning apparatuses may be employed for positioning various types of elongate workpieces, such as workpieces of profiled material (for example aluminium and plastics), timber pieces etc. Hereinafter the present invention will be exemplified in one embodiment in which the workpieces are timber pieces. In prior art positioning apparatuses for handling timber, the timber workpieces are fed resting on a feed conveyor such that the longitudinal direction of the timber pieces is transversely directed in relation to the direction of feed of the conveyor. In the positioning operation proper, the timber pieces are displaced in their longitudinal direction by means of rollers whose longitudinal directions are approximately parallel with the direction of feed of the feed conveyor. As a result of action from these rollers, the timber pieces will be displaced transversely of the direction of feed of the feed conveyor. For positioning individual timber pieces, use is made of an abutment against which the individual workpieces are displaced such that the transversely directed displacement is arrested and thereby the ends of the timber pieces become positioned. The abutment is placed in such a manner that it is located at the end regions of the rollers by means of which the timber pieces are transversely displaced. The above-described, prior art construction may function satisfactorily in such situations where the demands on output capacity are not too exaggerated. If, thus, the speed of the feed conveyor is slow, the transverse displacement need not take place at any high speed either, for which reason the risk that the timber pieces strike the abutment and thereafter bounce is slight. If, on the other hand, the speed of the feed conveyor is increased, the transverse displacement speed must also be increased, for which reason bouncing occurs between the timber pieces and the abutment. As a result, the precision in the sought-for positioning deteriorates considerably. In many contexts, a combination of extremely tight tolerances is required as regards the positioning of the individual timber pieces, often tolerances of less than 1 mm. Simultaneously with this precision requirement, demands are also placed on high feeding speed of the feed conveyor, in which event speeds as high as 100 m/min. or more may come into consideration. Such capacity output and precision requirements cannot be combined employing prior art equipment. PROBLEM STRUCTURE The present invention has for its object to design the positioning apparatus described by way of introduction such that it may operate at highly intensified speeds, at the same time as the requirements on precision in the positioning operation may be placed extremely highly. The present invention further has for its object to realise an apparatus which is operationally reliable and simple in design and construction. SOLUTION The objects forming the basis of the present invention will be attained if the positioning apparatus intimated by way of introduction is characterized in that the abutment means are disposed on a conveyor which runs along and synchronously in the same direction as the feed conveyor. Suitably, it further applies according to the present invention that the operative length of the transverse displacement device, seen in the direction of feed of the feed conveyor, substantially corresponds with the operative length of the conveyor of the abutment means. As a result of the above-described features, a construction will be realised in which the transversely directed movement of the individual timber pieces may take place at relatively slow speed in relation to the abutment means even though the feed conveyor runs at high speed. As a result, the risk is also eliminated of " bouncing between the timber pieces and the abutment means; and precision will be improved considerably. Further advantages will be attained according to the present invention if the apparatus is also given one or more of the characterizing features as set forth in appended Claims 3 to 6. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawings. In the accompanying Drawings: Fig. 1 is a schematic top plan view of the apparatus according to the present invention; Fig. 2 shows the apparatus of Fig. 1 seen in the direction of the arrow B in Fig. 1; Fig. 3 shows a modified embodiment in a view corresponding to that of Fig. 1; Fig. 4 shows the modified embodiment in a view corresponding to that of Fig. 2; and Fig.5 is a section taken along the section line A-A in Fig.4. DESCRIPTION OF PREFERRED EMBODIMENT As was intimated above, the present invention may be applied in the positioning of different types of elongate workpieces, such as workpieces of tubular material, profiled material, timber etc. The material in the workpieces may also vary. However, the present invention will be described for purposes of exemplification below in connection with the positioning of timber workpieces. In Fig. 1, reference numeral 1 relates to chains, belts or the like which are included in a feed conveyor for the timber pieces 2. The chains or belts move in a feed direction according to the arrow 3. The chains 1 are supported by means of suitable support members (not shown on the Drawing) and run over wheels or the like (not shown). Further, the chains are provided with drivers 4 which advance the workpieces 2 ahead of them. The apparatus according to the present invention further includes transverse displacement devices 5 which are intended for feeding the timber pieces in their longitudinal directions transversely of the direction of feed of the conveyor 1. The transverse displacement devices include at least two rollers 6 or the like which are rotary in accordance with the arrows 7 around shafts which are substantially parallel with the feed conveyor 1 and its direction of feed 3. The upper surfaces of the rollers 6 are located on a slightly higher vertical level than the upper sides of the feed conveyor 1. Hereby, the rollers 6 will, when they rotate in accordance with the arrows 7, transversely displace the timber pieces 2 in the direction of the arrow 8. At the same time, the timber pieces 2 will be displaced by the feed conveyor 1 in the direction of the arrow 3, the timber pieces sliding on the rollers 6 in their longitudinal direction. Suitably, the shafts of the rollers 6 are aligned such that they deviate somewhat from a parallel state with the direction of feed of the feed conveyor 1 in such a manner that the rollers 6 impart to the timber pieces a movement component in the same direction as the feed direction 3. Hereby, the timber pieces 2 will be somewhat lifted forwards from the drivers 4 or at least the friction against them will be reduced. The oblique inclination which is required for achieving such a result implies that the right-hand ends of the rollers 6 in Fig. 1 are to be displaced in an upward direction in the Drawing. The apparatus according to the present invention further includes a second conveyor 9 which has chains, belts or the like 10 which run over wheels 16 shown in Fig. 2, with centre axes 11. The chains 10 in the conveyor 9 are mutually interconnected via a number of crosspieces 12 which are provided with anchorages for abutment means 13. The conveyor 9 displays the same direction of movement as the feed conveyor 1 and runs synchronously with it. Further, its direction of movement is substantially parallel with the direction of movement 3 of the feed conveyor. The synchronous movement is further such that one crosspiece 12 always follows the position of one timber piece 2 ahead of a driver 4 on the feed conveyor 1. On the Drawings, the abutment means 13 have, for simplicity's sake, been illustrated as pins of circular cross section. However, precision gains may be made if they are platform or buffer in shape so that they cover and abut against the greater part of the end surfaces 14 of the timber pieces. In the position a in Fig. 1, one of the crosspieces 12 is located in register with a timber piece 2 which has just been fed in on the transverse displacement devices 5. This implies that the timber piece in position a begins to move in a direction towards the conveyor 9 and the abutment means 13 disposed thereon. In position a, the previously mentioned movement has just begun, for which reason the end 14 of the timber piece is located a distance from the adjacent abutment means 13. As the timber pieces 2 are fed in the direction of feed 3, they are also displaced in the transverse displacement direction 8 in a direction towards the abutment means. In position b, this displacement has been completed so that the end 14 of the timber piece 2 is located in contact with the abutment means 13. For fine calibration of the positioning of the timber pieces 2, an abutment rail 15 is disposed at the discharge end of the conveyor 9, the abutment rail being adjustable in a direction towards and away from the feed conveyor 1 corresponding to the relevant abutment means 13. When the timber piece passes from b to position c at the abutment rail, the end 14 of the timber piece will slide along this rail so that all tendencies towards bouncing and the like will have time to fade. At the discharge end of the abutment rail 15, the transverse displacement devices 5 with their included rollers 6 also terminate, so that, after the passage of the abutment rail 15, there no longer exists any force transversely of the direction of feed 3. In this state, the timber pieces are thus positioned with the end 14 in an extremely accurate manner. Fig. 2 shows the apparatus according to Fig. 1 seen in a pure horizontal side elevation in the direction of the arrow B. It will be apparent from Fig. 2 that the chain or belt 10 in the conveyor 9 runs over wheels 16 with the above- mentioned centre axes 11. In Fig. 2, the abutment means 13 are shown schematically and are illustrated only in the form of upstanding pins. It will be apparent from Fig. 1 that the crosspieces 12 in the conveyor 9 have a plurality of fixed positions for the abutment means 13. In all of these positions, there are abutment means, but these are movable between upwardly directed, active positions and retracted, passive positions. This is realised in that the abutment means 13 are displaceable in the crosspieces 12 between the active position illustrated at the upper part of the conveyor 9 in Fig. 2 to the retracted, passive position which is shown at the lower part of the conveyor. For switching the abutment means between the active and the passive positions, an activator 17 and a recuperator 18 are employed. The recuperator is technically in the form of a guide plate 19 against which the outer ends of the abutment means 13 come into contact, the abutment means being urged into their sockets in the crosspieces 12 to the passive position. This is realised in that the guide plate 19 and the lower part of the conveyor 9 form a cuneiform space which tapers in the direction of movement of the conveyor. In a corresponding manner, the activator 17 has a number of guide rails 20 which are disposed to form, on the lower part of the conveyor 9, a cuneiform space tapering in the direction of movement of the conveyor. When an abutment means 13 enters into this space and comes into contact with the guide rail 20, the abutment means is urged through its socket in the crosspiece 12 out to the active position. The guide rails 20 which are the same in number as the number of rows of abutment means 13 (see Fig. 1), are switchable between the active position illustrated in Fig. 2 by means of a switching device in the form of a cy Under unit 21. On retraction of the cylinder unit 21, the left-hand end of the guide 20 in Fig. 2 is lifted in an upward direction so that an abutment means 13 may pass without being urged out to the active position. Given that the abutment means can, in this manner, be activated in rows to the active positions or pass the activator 17 without being activated, the positioning of the ends 14 of the timber pieces 2 may be varied stepwise with great accuracy. DESCRIPTION OF ALTERNATIVE EMBODIMENTS Figs. 3-5 show a slightly modified embodiment of the present invention. In Fig. 3, the reference numerals from Fig. 1 have been inserted, and it should be observed that the design, construction and function of the feed conveyor 1 and the transverse displacement device are unchanged. That which has been changed in this embodiment is merely the conveyor 9 and the anchorages of the abutment means 13 therein. In the embodiment according to Figs. 3-5, the abutment means are one in number per crosspiece 12 in the conveyor 9 and, further, the abutment means are displaceable along the longitudinal direction of the crosspieces 12. It will be apparent from Fig. 4 that the abutment means 13 on the inside of the conveyor 9 have guide bodies 22 which are disposed for displacement of the abutment means along the crosspieces 12. The guide bodies 22 are place so as to cooperate with a recuperator 18 and an activator 17 in a manner which is analogous with that described above with reference to Fig. 2. The recuperator 18 includes a guide rail 23 which is obliquely inclined in relation to the direction of movement of the lower part of the conveyor 9. When a guide body 22 comes into abutment against the guide rail 23, the guide body and the connected abutment means 13 are displaced in the longitudinal direction of the associated crosspiece 12 in order to be placed at the end of the crosspiece located most proximal the feed conveyor 1. This corresponds to a displacement of the guide body 22 from position d to position e in Fig.5. The activator 17 in the embodiment according to Figs. 3-5 has been designed as a guide profile 24 in which the guide bodies 22 may be accommodated and displaced in the longitudinal direction of the guide profile. The guide profile is pivotally secured at its end located in position e in order there to accommodate a guide body 22 in a recuperated position, and thereafter lead the guide body to the activated position in position f. For displacement and adjustment of the guide profile 24, there is provided a switching unit in the form of a piston/ cylinder unit. The switching unit 25 is further provided with two mutually guide plates 26 which impart a terminal and accurate positioning to the abutment means 13 and the associated guide body 22. Finally, the embodiment according to Figs. 3-5 suitably includes some appropriate mechanism for locking the abutment means 13 in the adjusted longitudinal position along the crosspieces 12. The present invention may be modified further without departing from the scope of the appended Claims.

Claims: WHAT IS CLAIMED IS: 1. An apparatus for positioning workpieces whose length is to be adjusted, comprising: a feed conveyor (1) by means of which the workpieces (2) are fed with their longitudinal direction substantially at right angles to the direction of feed (3) of the feed conveyor, transverse displacement devices (5) disposed to displace the workpieces (2) in their longitudinal direction (8) transversely of the direction of feed (3), and abutment means (13) for arresting the transverse displacement movement (8) of the workpieces, whereby the one end (14) of the workpieces is positioned, characterized in that said abutment means (13) are disposed on a conveyor (9) which runs along and synchronously in the same direction as the feed conveyor (1). 2. The apparatus as claimed in Claim 1, characterized in that the operative length of the transverse displacement device (5) seen in the direction of feed (3) of the feed conveyor (1) substantially corresponds to the operative length of the conveyor (9) of said abutment means (13). 3. The apparatus as claimed in Claim 1 or 2, characterized in that said abutment means (13) are adjustable on the conveyor (9) towards and away from the feed conveyor (1). 4. The apparatus as claimed in Claim 3, characterized in that said abutment means (13) are stepwise adjustable. 5. The apparatus as claimed in Claim 3, characterized in that said abutment means (13) are continuously adjustable. 6. The apparatus as claimed in any of Claims 1 to 5, characterized in that the direction of action (8) of the transverse displacement devices (5) includes a component which is directed in the same direction as the direction of feed (3) of the feed conveyor (1).

Inventors: GUNNARSSON CENNETH, GUNNARSSON, CENNETH
Applicants: GUNNARSSON CENNETH, GUNNARSSONS VERKSTADS AB C, C GUNNARSSONS VERKSTADS AB, GUNNARSSON, CENNETH
Application year: 1998
Main classification: B65G47
IPC codes: B27B5, B27B25