DEVICE AT AN ELEVATOR FOR SEPARATION OF BOARDS

Abstract: Device at an elevator for separation of boards (6) from a magazine in which the elevator comprises a stand (1) carrying two or more carrier chains (2), each carrier chain (2) running partly over an upper pulley wheel (3), partly over a lower pulley wheel (4) and showing carriers (2.1) upon which the boards (6) are lifted. Two or more acceleration devices (8) are arranged at the top of the upper pulley wheels (3) and showing acceleration members protruding over and above the motion path of the carriers (2.1) and having a greater periphery speed than the speed of the carriers (2.1). The acceleration devices may consist of accelerating wheels (8).

Description: DEVICE AT AN ELEVATOR FOR SEPARATION OF BOARDS TECHNICAL FIELD The present invention relates to a device at an elevator for the separation of boards from a magazine in which the elevator comprises a stand carrying two or more carrier chains. Each carrier chain runs partly over an upper pulley wheel and partly over a lower pulley wheel and shows carriers upon which the boards are lifted. DESCRIPTION OF THE INVENTION The object of the present invention is to achieve a device at an elevator for separation of boards from a magazine in which boards are put down in the same longitudinal direction but overlap one another in an orderly pile. The elevator according to the invention comprises a stand carrying two or more carrier chains, each carrier chain running partly over an upper pulley wheel, partly over a lower pulley wheel and showing carriers upon which the boards are lifted. Two or more acceleration devices are arranged at the top of the upper pulley wheels and showing acceleration members protruding over and above the motion path of the carriers and having a greater periphery speed than the speed of the carriers . Preferably the acceleration devices consist of accelerating wheels that may be freely rotating on a first driving axle that also is arranged for driving the upper pulley wheels by means of a first motor. The accelerating wheels may preferably be driven via driving chains from a common second driving axle that is connected with a second driving motor. Each accelerating wheel shows preferably peripheral arranged teeth upon a diameter that is slightly above the outer path of the carrier chain when it passes over the upper pulley wheel, i.e. the teeth of the accelerating wheel protrude over and above the carriers at the upper pulley wheel. Furthermore the accelerating wheels rotate with a greater rotation speed than the pulley wheels whereby the teeth of the accelerating wheel get a greater peripheral speed than the carriers at the upper pulley wheels. When boards that are fed from the magazine by means of the carriers reach the pulley wheels, their motion speed is increased by means of the accelerating wheels. This is utilised among other things to separate two boards that are lifted jointly onto a number of equally located carriers as the board first arriving at the accelerating wheels thereby quickly is put onto the cross conveyor meanwhile the following board arrives at the accelerating wheels. In an alternate embodiment of the device according to the invention the acceleration devices may consist of driving chains that also may run over further pulley wheels on one or more axles parallel to the driving axles . Further features and characteristics concerning the present invention are evident from the description to the drawings subsequently and from the claims. DESCRIPTION TO THE DRAWINGS The invention is described subsequently as an example of an embodiment in connection with the enclosed drawings . Figure 1 shows an elevator for cross feed of boards seen from one long side. Figure 2 shows magnified a section of the left end of the elevator according to figure 1. Figure 3 shows magnified a cross section through the elevator according to figure 1. The elevator shown in the figures comprises a stand 1 placed upon a frame, for instance a floor in a sawmill. The stand 1 comprises an upper horizontal beam 1.1 and a lower horizontal beam 1.2 and carries a number of carrier chains 2 provided with carriers 2.1 running in planes transversely to the longitudinal direction of the elevator where each carrier chain 2 runs over an upper pulley wheel 3 and a lower pulley wheel 4 and via an upper sliding member 5.1 and a lower sliding member 5.2, both supporting the carrier chain 2. The upper pulley wheels 3 are driven by a first electric motor 3.2 via a driving axle 3.1 common to all pulley wheels 3. Boards 6 are distributed in the direction of arrow A in figure 3 from a magazine of boards at the lower end of the elevator, not shown in the figures, and up to a number of interacting distributing arms 7 from which one board at a time is placed upon a transverse conveyor for distribution to an edging saw mill. The distributing arms 7 are controlled by means of hydraulic cylinders 7.1 and lowered in the direction of arrow B in figure 3 when placing a board 6. A number of accelerating wheels 8 are arranged freely rotating on the upper driving axle 3.1 and placed between two adjacent carrier chains 2. Each accelerating wheel 8 is driven via a driving chain 9, in its turn driven by a chain wheel 9.1 that is arranged power transmitting on a common lower driving axle 9.2 that in its turn is driven by a second electric motor 9.3. Each accelerating wheel 8 shows peripherally arranged teeth, placed on a diameter that slightly exceeds the outer path of the carrier chain 2 when passing over the outer pulley wheel 3, i.e. the teeth of the accelerating wheel 8 protrude over and above the carriers 2.1 at the upper pulley wheel 3. Also the accelerating wheels 8 rotate with a higher rotation speed than the pulley wheels 3 whereby the teeth on the accelerating wheel 8 get a higher periphery speed than the carriers 2.1 at the upper pulley wheels 3. When boards 6 that are fed from the board magazine by means of the carriers 2.1 reach the pulley wheels 3 their motion speed is increased by means of the accelerating wheels 8. This is made use of among other things to separate two boards that are lifted together on a row of uniformly located carriers 2.1 and where the board that first reaches the accelerating wheels 8 in that way is thrown rapidly down onto the distributing arms 7 and placed upon the cross conveyor meanwhile the following board reaches the accelerating wheels 8. It lies within the scope of the invention to replace the accelerating wheels 8, as described above, with tooth-provided chains with the same functioning, i.e. the driving chains 9, as described above, may be provided with teeth that protrude over and above the carriers 2.1 on the carrier chains 2. Those driving chains may also be arranged to run over an additional set of pulley wheels located along an additional axle parallel to the upper driving axle 3.1. By this it is made possible to additionally separate two adjacent boards that are taken up by a row of carriers 2.1 on the carrier chains 2. It also lies within the scope of the invention to drive the carrier chains 2 via a lower driving axle, common for all lower pulley wheels 4, instead of an upper driving axle 3.1. The upper pulley wheels 3 are then free rotating like the accelerating wheels 8 or replaced with sliding devices but otherwise the same functioning concerning the acceleration and separation of the boards.

Claims: CLAIMS 1. Device at an elevator for separation of boards (6) from a magazine in which the elevator comprises a stand (1) carrying two or more carrier chains (2), each carrier chain (2) running partly over an upper pulley wheel (3) , partly over a lower pulley wheel (4) and showing carriers (2.1) upon which the boards (6) are lifted, c h a r a c t e r i z e d in that two or more acceleration devices (8) are arranged at the top of the upper pulley wheels (3) and showing acceleration members protruding over and above the motion path of the carrier chain (2) and that have a greater periphery speed than the speed of the periphery chain (2) . 2. Device according to claim 1, c h a r a c t e r i z e d in that the acceleration devices consist of accelerating wheels (8) . 3. Device according to claim 2, c h a r a c t e r i z e d in that the accelerating wheels (8) are freely rotating on a first driving axle (3.1) for driving the upper pulley wheels (3) . 4. Device according to claim 2 or 3 , c h a r a c t e r i z e d in that the accelerating wheels (8) are driven via driving chains (9) from a common second driving axle (9.2) . 5. Device according to claim 1, c h a r a c t e r i z e d in that the acceleration devices consist of driving chains (9) . 6. Device according to claim 5, c h a r a c t e r i z e d in that the acceleration devices in the shape of driving chains (9) run over further pulley wheels on an axle parallel to the driving axles (3.1, 9.2).

Inventors: LOEVKVIST HAAKAN, LOEVKVIST, HAAKAN
Applicants: LOEVKVIST HAAKAN, PARIS TRAE & METALL AB, LOEVKVIST, HAAKAN
Application year: 1998
Main classification: B65G37
IPC codes: B65G17, B65G47