METHOD AND APPARATUS FOR REPLACING HIDE STRETCHING FRAMES IN A HIDE STRETCHING MACHINE

Abstract: Method and apparatus of replacing hide stretching frames in a hide stretching machine, comprising a hide changing table on which said stretching frames can be placed for the exchange of hides. The sides of said hide changing table (1) are provided with vertically liflable and descendable frames (8a, 8b) fitted with two tracks (9, 10; 11, 12) on top of each other for rollers mounted on the edges of stretching frame. There is an openable and closeable connection (16, 13) between the tracks (9, 10; 11, 12) for transferring the stretching frames from the upper track (9; 11) onto the lower track (10; 12) prior to the exchange of stretching frames. For quicker replacement of the hide stretching frames, the stretching frame, arriving off the track out of said drying device and having a dried removable hide mounted thereon, is passed onto the upper track (9; 11) of lift frames (8a, 8b) substantially simultaneously as the stretching frame lying of the lower track (10; 12) of such lift frames is passed onto a track leading into said drying device, whereafter lift frames (8a, 8b) are descended to the lowered position for lowering a just arrived stretching frame onto hide changing table.

Description: Method and apparatus for replacing hide stretching frames in a hide stretching machine. The present invention relates to a method and appratus for the replacement of hide stretching frames in a hide streching machine, comprising a hide changing table on which the stretching frames can be set and which is provided with means for translating stretching clamps along the radial sliding guides of the stretching frames. Such an apparatus has been disclosed in the Applicant's Finnish Patent Publication No. 55682. This apparatus has proved itself very useful and successful and, thus, the object of the present invention is to develop it further for substantial increase in the production rate. Prior to the invention disclosed in this application, the replacement or change of hide stretching frames was effected as follows. On each side of the hide * changing table there were rails along which the hide stretchijig frames were run on rollers. When the hide had been stretched in the stretching frame, the latter was lifted up by means of the rails in such a manner that the stretching frame could be pushed onto the receiving track of a drying tunnel. There¬ after, it was possible to pull from the entrance track of said drying tunnel another stretching frame onto the rails and lowered down on the hide changing table. Pushing of a stretching frame off the rails and pulling of another stretching frame on the rails were effected manually. With this arrangement, a considerable part of the time spent for the change of hides was used for the replacement of stretch¬ ing frames between the hide changing table and drying tunnel. The object of the present invention is to provide a method and apparatus for substantially quicker replacement of hide stretching frames than heretofore. According to the method of the invent on, this object will be accomplished by providing the hide changing table wi'th two receiving and supporting tracks on top of each other for passing a stretching frame leaving the hide drying device onto the upper track and for removing another stretching frame, entering said drying device, substantially simultaneously off the lower track, as well as by lowering the stretching frame now on the upper track onto the lower track prior to the exchange of the stretching frames. This arrangement reduces the time spent for the exchange of hide stretch¬ ing frames to substantially half of what it used to be. The appratus of the present invention for carrying out the above method is characterized in that the sides of a hide changing table are fitted with vertically lifted and lowered frames provided with two tracks on top of each other for the rollers on the edges of a stretching frame, and that between the tracks there is an openable and closeable connection for replacing the stretching frames from the upper to lower track. The speed of exchanging hide stretching frames can be further increased with a preferred embodiment of the invention in which the terminal end of the upper track of at least one of the lift frames is fitted with a damper means for stopping the movement of an arriving stretching frame and the outset end of the lower track, aligned with the above terminal end, is fitted with a thrust member for pushing the stretching frame into said drying device. Hence, the arriving stretching frame can travel at high speed e.g. by virtue of the inclination of the arrival track and, on the other, e.g. a pneumatic thrust member can be used to give the leaving stretching frame a relatively high speed. With these procedures of the invention, the exchange of replacement time of hide stretching frames has been managed to be reduced to minimum, which substantially reduces the overall time required for replacing another hide in the stretching frame, i.e. for removal of the hide dried in the drying device, for spreading the hide to be dried on the frame and for stretching the hide by translating the stretch¬ ing clamps radially outwards. The overall time spent for hide exchange has been managed to be reduced by the method and apparatus of the invention by considerable precentage resulting in substantial improvement in the total capacity of a hide stretching machine. The following is a more detailed description of one embodiment of the invention with reference made to the accompanying drawings, in which fig. 1 is a schematical side view of the end of a drying tunnel with a hide changing table associated therewith. Fig. 2 is a plan view of a hide stretching frame in larger scale. Figrs. 3 and 4 show the lift frames associated with a hide changing table and having two tracks on top of each other for the stretching frame rollers. In figure 1, the hide changing table is designated by reference numeral 1 and drying tunnel with numeral 2. A hide stretching frame 3, as shown in figure 2, is arranged to be conveyed on its rollers 4 and 5 along tracks 6 and 7 of said drying tunnel 2. The stretching frame to be removed from the hide changing table 1 and having a fresh hide stretched thereon is trans¬ ferred along the lower track 6 into the drying tunnel and replaced by a stretching frame pulled off the upper track 7 and provided with a dried hide. For this exchange of hide stretching frames each side of hide changing table 1 is pro¬ vided with lift frames 8 fitted with receiving and supporting tracks and being liftable and lowerable between the upper and lower position shown in fig. 1 by dashed and dotted lines and solid lines, respectively. In the following, the design of said lift frames is described in more detail referring to figures 3 and 4. Fig. 3 shows a lift frame 8a disposed on one side of hide changing table 1 and intended to receive the rollers 4 of stretching frame 3. A lift frame 8b, as shown in fig. 4, is intended to receive a roller 5 on the other side of stretching frame 3. Lift frame 8a is provided with an upper roller track 9 and a lower roller track 10. Accordingly, lift frame 8b is fitted with an upper roller track 11 and a lower roller track 12. In lift frame 8a, the central web that separates the roller tracks 9 and 10 from each other comprises openings 16, the distance between said openings corresponding to that between rollers 4. Openings 16 are arranged to be opened and closed by means of slides 13 which are pulled by pneumatic cylinders 14 against the force of return springs 15. Accordingly, in lift frame 8b, an opening 16 between roller tracks 11 and 12 is arranged to be opened and closed by a slide 13 operated by a pneumatic cylinder 14 and a return spring 15. Lift frames 8a and 8b are arranged to be lifterd by means of lifting cylinders 18 connected to each other by means of a chain transmission, not shown, in such a manner that both lift frames 8a and 8b travel up and down simultaneously. Lift frame 8a is further fitted with a damper means 19 at the upper track 9 stopping the speed of a stretching frame arriving from the drying tunnel track 7. The forward end of lower track 10 is provided with a thrust member 20 for pushing a stretching frame onto the lower drying tunnel track 6. Damper means 19 is connected to a pneumatic cylinder 21 and thrust member 20 to a bi-functionally operated pneumatic cylinder 22. The apparatus operates as follows. With lift frames 8 in elevated position, the thrust member 20 displaces a stretching frame 3, supported on lower tracks 10, 12, onto the drying tunnel lower track 6 while simultaneously another stretching frame slides off the drying tunnel upper track onto the upper tracks 9, 11 by means of inclination of the track and/or a conveyor. Thereafter the lift frames 8a, 8b are descended to the lowered position, whereby the stretching frame 3, having a dried hide secured ^ thereto, will rest upon the hide changing table 1. The exchange of hides on stretching frame 3 is effected as described in the above-mentioned Patent 55682. Thereafter, the slides 13 of both lift frames are opened and the latter elevated by clinders 18, the stretching frame thus moving onto the lower tracks 10, 12, with rollers 4, 5 being able to pass through openings 16. With lift frames 8a and 8b in their elevated position, the exchange of stretchj.ng frames is re-effected the same way. By virtue of this arrangement, the time required for the exchange of stretching frames 3 has been managed to be reduced so as to be relatively short compared with the time spent for the replacement of the hide itself.

Claims: Claims 1. A method of replacing hide stretching frames (3) in a hide stretching machine, comprising a hide changing table (1) on which said stretching frames (3) can be placed for the exchange of hides, c h a r a c t e r i z e d in that in connection with said hide changing table (1) there are employed two receiving and supporting tracks (9, 10; 11, 12) for passing a stretching frame, arriving from a hide drying device (2) , onto the upper track (9; 11) and for removing substantially simultaneously another stretching frame, entering said drying device, off the lower track (10; 12) , and that, prior to the exchange of stretching frames (3) , the stretching frame (3) lying on the upper track (9; 11) is lowered onto the lower track (10; 12) . 2. A method of claim 1, c h a r a c t e r i z e d in that the stretching frame (3) , arriving off the track (7) out of said drying device (2) and having a dried removable hide mounted thereon, is passed onto the upper track (9; 11) of lift frames (8a, 8b) disposed on the sides of hide changing table (1) substantially simultaneously as the stretching frame (3) lying on the lower track (10; 12) of such lift frames is passed onto a track (6) leading into said drying device (2) , whereafter lift frames (8a, 8b) are descended to the lowered position for lowering a just arrived stretching frame onto hide changing table (1) and, after the exchange of hides has been effected, stretching frame (3) is transferred from the upper track (9; 11) onto the lower track (10; 12) by elevating lift frames (8a, 8b) upwards and by opening the connection between tracks (9, 10; 11, 12) at the stretching frame rollers (4, 5) , whereafter the connection between the tracks s^re-closed and said simultaneous exchange of stretching frames (3) is effected. .' 3. An apparatus for embodying the method of claim 1 or 2, said apparatus comprising a hide changing table (1) on which stretching frames (3) can be mounted and which is fitted with means for translating stretching clamps along the radial ^NATlO^ sliding guides of stretching frames (3) , c h a r a c t e r i z e d in that the sides of said hide changing table (1) are provided with vertically liftable and descendable frames (8a, 8b) fitted with two tracks (9, 10; 11, 12) on top of each other for rollers (4, 5) mounted on the edges of stretching frame (3) , and that there is an openable and closeable connection (16, 13) between the tracks (9, 10; 11, 12) for transferring the stretching frames from the upper track (9; 11) onto the lower track (10; 12) . 4. Apparatus of claim 3, c h a r a c t e r i z e d in that the terminal end of the upper track (9) of at least one (8a) of the lift frames is fitted with a damper means (19, 21) for stopping the movement of arriving stretching frame and the forward end, lying at the corresponding location, of the lower track (10) is fitted with a thrust member (20, 22) for pushing the stretching frame into said drying device. 5. Apparatus of claim 3 or 4, c h a r a c t e r i z e d in that the openable and closeable connection between said tracks consists of pneumatic and spring-operated slides (13) .

Inventors: VILJANMAA A
Applicants: VILJANMAA A
Application year: 1981
Main classification: C14B1
IPC codes: C14B1