A NEW SLAT LIFTING UNIT FOR BLIND MAKING MACHINES

Abstract: A lifting unit for a blind making machine which uses a rotating arm which has a cross pin or pins or roller to actually lift the slats of the blind being made, the cross pin or pins having adjustable positions so that all types or sizes of blind can be made using the same blind making machine.

Description: A NEW SLAT LIFTING UNIT FOR BLIND MAKING MACHINES The invention is a new way for an automatic blind making machine to lift slats and at the same time place the ladder cord in the correct position. A window blind as shown in figure 1 is made up of slats 1. which are threaded between the steps 2. of ladder cords 3. There are lifting cords 4. which go through the holes in the slats and are fixed to a beam 5. at the bottom of the blind, which when pulled, lift the whole blind up. The steps of the ladder cords lie on alternative sides of the lifting cord, which gives the blind some stability and prevents it falling apart when transported or during installation. A blind making machine can be said to comprise of three sections : Slat band feeding ; Hole punching and cut-off ; slat lifting. Such a machine is shown in figure 2. The slat band is fed into the machine via the rubber covered rollers 6. of the slat band feed unit. The hole punching and cut-off section punches the holes in the slat band for the lifting cords and also cuts off the the end of the previous slat which has been fed into the lifting section. The lifting section builds the blind. In this section the slats are fed into the correct position between the steps of the ladder cords and then lifted up to be held by spring clips of a magazine. When the slat is lifted the step of the ladder cord is guided to be alternatively on the right or the left side of the hole in the slat used for the lifting cord. During manufacture or when the blind is completed the lifting cords are threaded through the holes in the slats making a complete blind. A blind making machine made using existing technique is shown in figure 3. The slats 7. have been previously lifted and the next slat 8. is shown being threaded between the steps 2. of the ladder cords 3. It can be seen that the steps 2. of the ladder cords 3. have been set in a zig zag form on either side of the holes in the slats of the previously lifted slats 7. The lifting of the slats and positioning of the ladder cord in zig zag form is at present accomplished in a number of alternative ways. One way shown in figure 3 is to have lift arms 9. which when lifted move laterally to one side and then the other. It is so that there are at least four alternative blind types or sizes that can be made. These four types have slat widths that are 16, 25, 35 and 50 mm. wide. For each blind type the slat arrives in the slat lifting unit at the same level. Each blind type uses a ladder cord with different step lengths, and for each type the height to which the slat must be lifted is different. Also for each type the lateral movement of the ladder cord required when the slat is lifted is different. The table below shows the four usual blind types, ladder cord step lengths, lift heights, and approximate lateral movements of the ladder cord required. Blind tvpe Ladder cord step Lift hf Lateral movement 16 13 19.5 12.0 25 21 31.5 19.4 35 30 45.0 27.7 50 41 61.5 37.8 All distances are in πύllimeters. The different Uft heights and transverse side movements required result in severe limitations for blind making machines at present in production. Some variation in Uft heights can be obtained by the use of removeable spacers attached to the lift arms and by chosing transverse movements that are a compromise between the movements required for two types of blind, a blind machine can then be made that can make two types of blind, for example 16 and 25 mm. or 25 and 35 mm. Blind machines built using current technique also have a problem in that the slats being fed into the ladder cords in the lifting section have a tendency to catch or snag on the edges of the ladder cord. The invention is only concerned with the lifting section of an automatic blind making machine. The basic invention is a lift unit that can make all types of blind, and also ensure that a slat can be fed between the steps of the ladder cords without any risk for catching or snagging. The invention is shown in figures 4 to 8. Figure 4 shows in perspective one station of the slat lifting unit of an automatic blind making machine. There must be at least two stations in operation when a blind is made, depending on the size of the blind. Slats that have already been lifted 7. are shown. These are held up by the spring clips of a magazine which is a standard unit for blind machines, and is not shown in the figure for clarity. In the invention an arm 10, is mounted on an axel 16. The arm 10. has a cross pin, arm, or roller 15. which can be set to different positions. When a slat 8. is fed into the lifting unit the arm is in the position as shown. The ladder cord 3. runs from the slats 7. around cross pin 15. then around a roller 12. and finally over a roller 13. Roller 13. can rotate on axel 16. and the plate 14. catches in the steps of the ladder cord. The spring 17. draws the roller 16. against the movement of the ladder cord thereby keeping the ladder cord under tension at all time. Such a spring loaded roller is standard techmque. Also shown in figure 4 is a slat guide 11. which has a U- channel in its top to guide the slat. When the arm 10. is in the position shown then the cross pin 15. draws the ladder cord over the end of the slat guide 11. to ensure that the ladder cord is perfectly prepared for the slat to pass cleanly between the steps of the ladder cord. It can be seen that by moving the cross pin 15. into the alternative positions in the arm 10. the suitable Uft height and transverse movement for all types of bUnds can be obtained. For each type of bUnd a different slat guide I L is used. An alternative is to have several arms with cross pins at different positions giving suitable Uft and transverse movements. These arms being exchangable and the correct arm being fitted to the unit for the bUnd being made. Figure 5 shows the invention again and the different positions to which the arm 10. rotates. The arm is in position A when a new slat 8. is fed into the Ufting unit. When the slat is to be Ufted the arm rotates to position B Ufting the slat, and then returns to position A. After the next slat has been fed into the Ufting unit the arm 10. moves to position C, Ufting the slat and then returns to position A. For the next slat the arm 10. moves to B and returns to position A. The arm 10 moves alternatively from position A to positions B and C. In this way the slats are Ufted and the ladder cord 3. is moved alternatively from side to side. Figure 6 shows an alternative to the single pin or roUer 15. In this alternative two arms are used in place of the single arm 15. The arms 18. are kept in a horizontal position during the movement of the arm by a spring or other mechanism. The advantage of having double arms 18. is that the ladder cord is moved away from the end of the slat guide 11. when the arm 10. moves from position A to positions B or C, Ufting the slat. Figure 7 shows another alternative which has two arms which move in parallel. This is easily achieved by driving both arms from the same band or chain. In this case the two arms 19. and 20. and their two arms or roUers 21. and 22. move simultaneously to Uft a slat. The axel 23. being longer than axel 24. to allow the arms 19. and 20. to rotate without colUding. In this case the arms 19. and 20. are exchanged for different arms for each bUnd type. Figure 8 shows another alternative in which a spring loaded arm 27. is mounted on the same axel 16. as the arm 10. When arm 10. moves to Uft a slat then the arm 27. and pin or roUer 28. also moves over a short distance until it contacts stop 25. In this way the pin or roUer 28. pushes the ladder cord over the end of the slat guide. In addition to the fact that the invention enables a bUnd making machine to make all sizes of blinds and ensures clean, snag free feeding of the slat between the steps of the ladder cords, the invention is cheap to manufacture and can be driven electrically, pneumatically or hydraulically. suBSTrruTE SHEEΓΓ (RULE 26)

Claims: Patent Claims 1. A slat lifting unit of a blind machine CHARACTERISED in that the lifting of the slat is obtained by a rotating arm, that has a cross pin or roUer that can be adjusted in position to suit the Ufting heights, and transverse movements of the step cord, required for all types of bhnds. 2. A slat Ufting unit as described in claim 1. above CHARACTERISED in that the rotating arm is exchangeable, an arm with cross pin or roller in a suitable position being fitted to suit the type of bUnd being made. 3. A slat Ufting unit as described in 1. or 2. above CHARACTERISED in that the cross pin or roUer draws the ladder cord over the end of the slat guide when the arm is in its lowest position, thereby ensuring a smooth entry for a slat entering the ladder cord via the slat guide. 4. A slat Ufting unit as described in claims 1. 2. or 3. above CHARACTERISED in that the arm has two pins or roUers to guide the ladder cord. 5. A slat Ufting unit as described in claims 1. 2. or 3. above CHARACTERISED in that there are two rotating arms with pins or rollers operating in parallel. 6. A slat Ufting unit as described in claims 1. 2. or 3. above CHARACTERISED in that there is a second arm that operates independently over a relatively short distance and has a pin or roller which pushes the ladder cord over the end of the slat guide. SUBSTTTUTE SHEET (RULE 26)

Inventors: ARCHER JOHN NEVILLE, ARCHER, JOHN, NEVILLE
Applicants: ARCHER JOHN NEVILLE, ARCHER, JOHN, NEVILLE
Application year: 1997
Main classification: E06B9
IPC codes: E06B9