| EP0281648A2 | 1988-09-14 | |||
| DE3507057A1 | 1986-08-28 | |||
| US3604483A | 1971-09-14 |
| 1. | A method for automated assembly of rectangular frame constructions, according to which method elongated frame members (la...Id) worked from both ends are joined together in an assembly apparatus to form a desired frame, c h a r a c t e r i z e d in that. |
| 2. | the members (la...Id) are fed into the assembly apparatus (3...8) in the proper assembly order of the desired frame,. |
| 3. | the successive members (la...Id) are joined pairwise together in the first unit (3...7) of the assembly apparatus to form the first and the second ortho¬ gonally joined frame halves (la, lb; lc. Id), each frame half (la, lb; lc. Id) is transferred from the first position to the second position by a 90° rotation in the plane of the frame, the first half (la, lb) of each frame is removed from the second position and further rotated 180°, after which the first half (la, lb) of each frame is brought in the plane of the frame without changing its orienta¬ tion against the matching second half (lc, Id) of the frame and the ends of the halves are joined together to form the frame. |
| 4. | A method as defined in claim 1, c h a r a c t e r ¬ i z e d in that the members (la...Id) are fed at least substantially longitudinally oriented to the assembly apparatus (3...8). |
| 5. | A method as defined in claim 1 or 2, c h a r a c ¬ t e r i z e d in that the second frame half (lc, Id) is transferred to the second #position at least substantially simultaneously with the 180° rotation of the first frame half (la, lb). |
| 6. | A method as defined in any foregoing claim, c h a r a c t e r i z e d in that the assembly apparatus used is comprised of a first rotatable fence unit (3...7) having on a planar surface (3) orthogonally protruding fences (4...7) delineating four compartments, of which one compartment at a time is brought to a first position, whereby the first frame half is assembled in said position, after which said compartment is transferred from the first position to the second position by rotating the fence unit 90° in the plane of the frame being assembled. |
| 7. | A method as defined in claim 4, c h a r a c t e r ¬ i z e d in that the first frame half (la, lb) is transferred by a lateral movement from the second position to the second fence unit (8) , the second fence unit (8) is rotated 180° in the plane of the frame half and the second fence unit (8) is moved laterally against the first fence unit (3...7) to push the first frame half (la, lb) against the second frame half (lc, Id) so as to join the halves together in said second position. |
| 8. | A method as defined in claim 4 or 5, c h a r a c ¬ t e r i z e d in that the first fence unit (3...7) is rotated after completion of the frame assembly by a further angle of 90° to bring the ready frame (la...Id) to the exit position. |
| 9. | A method as defined in any foregoing claim 4...6, c h a r a c t e r i z e d in that the first fence unit (3...7) is rotated 90° after the feed of every second member, advantageously in the assembly order after the feed of the first (la) and the third (lc) member. |
| 10. | A method as defined in any foregoing claim 4...7, c h a r a c t e r i z e d in that the first (la) and the third (lc) member of the fence in the assembly order of the frame are fed to the compartment which precedes the compartment in the first position. |
| 11. | An apparatus for automated assembly of frame structures*, c h a r a c t e r i z e d in that said apparatus comprises a first rotatable fence unit (3...7) having four compartments delineated by four orthogonally projecting rectangular fences (4...7),. |
| 12. | a first transfer device (2) capable of transferring members (la...Id) to be assembled into a frame in their longitudinal direction to a desired compartment of the first fence unit (3...7) , where the members can be joined together pairwise to form halves (la, lb; lc. Id) of the frame structures,. |
| 13. | drive means for rotating the first fence unit (3...7) in steps of 90° about the unit's center axis after the completion of each frame half (la, lb; lc. Id) and after the feed of the first member (la) of each frame, a second fence unit (8) rotatable about its center axis,. |
| 14. | a second transfer device capable transferring the frame halves (la, lb) joined in the first fence unit (3...7) at a desired instant from the first fence unit to the second fence unit (8) , drive means for rotating the second fence unit (8) in steps of 180° about the unit's center axis to rotate the frame half (la, lb) by an angle of 180°, and. |
| 15. | a third transfer device for transferring the rotated frame half (la, lb) from the second fence unit to the first fence unit (3...7) to complete the assembly of the frame. |
| 16. | An apparatus as defined in claim 9, c h a r a c ¬ t e r i z e d in that the third transfer device is adapted to move the second fence unit (8) against the first fence unit (3...7) . |
The present invention relates to a method according to the preamble of claim 1 for automated assembly of rectangular frame structures.
According to the present method, elongated pieces worked from both ends are joined together in an assembly jig to form a desired frame construction.
The invention also concerns an apparatus according to the preamble of claim 9 suited to the automated assembly of rectangular frame constructions.
The construction industry uses different types of frames in window and door openings as well as in windows and doors adapted to such framed openings. The frames are typically assembled from four different parts, which are pairwise identical (2 + 2) . The ends of the frame pieces are worked for a dowel or tongue-and-groove joint permit¬ ting their mutual joining, whereby the joint is conven¬ tionally fortified by gluing or nailing.
According to conventional techniques, members for such 2+2 element frames (e.g., window sashes) are fabricated in long series. For the assembly of the frame, members of the frame are retrieved from the buffer stores of the production facility, two of each length at a time and assembled together in a jig so designed as to check the dimensions and orthogonality of the joint.
Automated assembly of frames has been difficult to implement because of the n «eed for picking the frame members from bins of the storage facilities or similar buffer stores. Furthermore, the prior-art methods have been hampered by the fact that the frame members being
joined are typically of differently oriented wood and worked from different parts of stock on the abutting sides of the joint, which results in warping from humidity variations frequently leading to the detachment of the joint.
It is an object of the present invention to overcome the drawbacks of the prior-art techniques and to provide an entirely novel concept for the automated assembly of rectangular frame constructions.
The present invention is based on the idea of assembling the frame members in the proper order, which is the natural assembly order of the frame members. To this end, the successive members are pairwise joined in the first position of the assembly apparatus to form the half- frames, which are subsequently transferred to the second position by rotating them 90° in the plane of the frame. The first half-frame of each frame being formed is next removed from this second position, rotated 180° and joined with the second half-frame.
More specifically, the method in accordance with the invention is principally characterized by what is stated in the characterizing part of claim 1.
Furthermore, the apparatus in accordance with the inven¬ tion is principally characterized by what is stated in the characterizing part of claim 9.
The natural assembly order of a frame in the context of this application refers to such an order in which the members of the frame are in the ready-assembled frame when the frame is rotated clockwise or counterclockwise. According to the starting point, the assembly order for a window frame can be, e.g., bottom rail, stile, top rail and stile.
The frame members can be fed in the proper order for assembly by working them in a two-way machining unit described in a parallel patent application. To remove problems caused by variations in stock properties, the production of the members is then .advantageously carried out by first forming stock of continuous length by, e.g., finger joints from lumber of limited length, after which the stock is cut to frame members of desired length. The members are worked for necessary joint portions in said machining unit, after which they are transferred onto a feed conveyor and moved to the assembly apparatus according to present invention.
The present invention can also be applied to the assembly of frame members manufactured by conventional methods that in this application are separately placed onto the feed conveyors in the proper order (that is, assembly order) of the frame. The members are fed to the assembly apparatus at least substantially oriented in their longitudinal direction.
The assembly apparatus according to the invention comprises a first rotatable fence unit having a planar table (turntable), which has the right-angle fences mounted on it extending up to the rim of the turntable from its center axis. The fences, or brackets, delineate four orthogonal compartments, of which one compartment at a time is brought to the first position of the apparatus. A half-frame is assembled in the compartment of the first position, after which said compartment is rotated from the first position to the second position by rotating the fence unit in the plane of the frame by 90° about the center axis of the turntable.
The apparatus has appropriate actuator means for both rotating the turntable and pushing the frame members to abut each other.
In normal operation, the first half-frame is transferred to the second fence unit in a lateral movement actuated by a transfer device. The second fence unit is rotated 180° in the half-frame plane, after which the half-frame rotated in this manner, is next moved laterally by a third transfer device back to the first fence unit, where it is joined with the half-frame located in the second position of the fence unit. Subsequently, the first fence unit is rotated by a further angle of 90° to bring the ready-joined frame to the exit position, where the frame is removed from the turntable and conveyed further to possible posttreatment phases such as finishing, glazing etc.
The turntable is rotated by 90° after the first and third frame member of the frame has been brought to the compartment preceding the compartment in the first position.
The invention makes it possible to overcome the drawbacks of the prior-art techniques described above. A distinct benefit of the present invention particularly worth noting is that the automated assembly of the frames in mass production is possible even if every subsequent frame differs from the preceding frame.
The invention is next examined in detail with the help of an exemplifying embodiment with reference to the appended drawing in which Figs. la...Id diagrammatically show step by step (A...L) in a top view the function of the method according to the invention.
The frame members are received from a machining unit in the proper order, which in the case of a window frame, for instance, is a bottom rail la first, next a stile lb, next a top rail lc and finally the second stile Id per each frame.
From the feed conveyor 2 the first member la of the frame is transferred in its longitudinal direction onto a turntable 3 beside a fence bracket 4. Next the member la is pushed toward the compartment 4-5 until it abuts a fence bracket 5. Next, the turntable 3 is rotated 90° about the center axis of its plane, whereby the first member la is also aligned at a 90° angle relative to longitudinal direction of the members lb—Id travelling on the feed conveyor 2. The feed track 2' for the members is shifted by the thickness of the fence bracket 4 toward the rotating direction of the table 3 and the next member is then fed from the conveyor 2 to the same compartment 4-5, The joining end of the member is sprayed with glue. The members la and lb are joined together by slipping the joining portion of the latter member lb past the joining portion of the former member la using a constant-torque actuator.
Next, the feed track 2' is shifted back to its former lateral position, in which it feeds the third member lc to the next compartment 7-4.
The turntable 3 is now rotated by 90° about its center axis, whereby the ready half-frame 2a, 2b is moved behind the just-fed member 2c to the second position. The first half-frame is removed from this position and slipped so as to abut a second crossed fence 8. The latter fence is rotated by 180°, after which the fences are pushed toward each other. The second position of the turntable now has a ready half-frame 2c, 2d, which was moved from the first position to the second position approximately
simultaneously as the second fence 8 is rotated 180°. By pushing the fences against each other, the joined frame
2a 2d is completed while the first fence unit is readying in the above-described manner a third half-frame 2e, 2f.
In order to check the dimensions of the assembled frame construction and to assure the completion of the joining operation, that is, satisfactory insertion of the joining ends into each other, the diagonal dimensions are verified automatically. The diagonal dimensions can be computed from the lengths of two members by taking into account the depth of the inserted joints. In the same manner as when the ratio of the short and long sides of a frame is known, the direction of the oblique vector H shown in Fig. lc can always be computed correctly to obtain the direction from the constant-torque actuator pushes the half-frames into a ready-assembled frame.