GB2084954A - Method and apparatus for packing a resilient body in compression and the body so packed - Google Patents

Abstract

Apparatus for packaging a compressible body e.g. a sponge into a tube has a surface (20) which receives the sponge between a fixed jaw (21) and an opposed movable jaw (23), the jaws having concave surfaces, which when the jaws abut, define a cavity for the compressed sponge. A platen 32 overlies the jaws (21, 23) and moves normal to the surface (20) between an open position, at which the sponge is positioned on the surface (20), and a closed position, in contact with the jaws, at which the sponge is flattened prior to being compressed further upon movement of the jaw (23) towards the fixed jaw (21). A tube is supported in a receiving position axially aligned with one end of the cavity and a plunger (31) aligned with the other end of the cavity ejects the compressed sponge from the cavity into the tube. Control means is connected to pneumatic actuators to operate them in sequence to move the platen (32) to the closed position, close the jaws (21, 23) and then eject the compressed sponge into the tube. The cross-sectional area of the sponge in its uncompressed state is 5 to 12, preferably 6 to 8, times that of the tube. <IMAGE>

Description

SPECIFICATION Method and apparatus for packing a resilient body in compression and article so packed The present invention relates to a process for packing a sponge or like compressible body into a tube in which the sponge is held in compression.

Sponges of synthetic plastics material are known for a wide range of domestic and like cleaning purposes. The invention is particularly valuable in relation to car cleaning sponges or bath sponges of relatively large size. The relative cost of transporting sponges from factory to consumer is high because sponges are relatively inexpensive products which occupy a large volume in relation to their weight. Even more significantly a display of sponges can occupy a disproportionate amount of shelf space in a retail outlet and for this reason retailers often put them in floor-standing storage bins where they are not displayed to advantage. Sponges have been sold which are temporarily heat set in a collapsed state and which return to their full size on immersion in water but this process is inconvenient and the resulting product does not have an attractive appearance.

We have found that it is possible to pack sponges of resilient cellular synthetic plastics material in compression within tubes of a transparent plastics material such as cellulose acetate the cross-sectional area of the sponge being from 5-10 times, preferably from 6-8 times that of the tube in which it is packed.

We have also devised an apparatus for packing a sponge or like compressible body into a tube where the sponge is held in compression. The said apparatus comprises a surface for receiving the sponge, a fixed jaw on the surface and an opposed movable jaw connected to a first actuator for travel over the surface between an initial open position in which a sponge may be placed between the jaws and a closed position in which the jaws abut with adjoining concave surfaces thereof defining a cavity for the compressed sponge, a platen overlying the fixed jaw and the movable jaw throughout its travel and connected to a second actuator for movement normal to the surface between a position spaced from the jaws to allow sponge insertion and a position in contact with the jaws so that the sponge may be flattened into a closed space which the platen defines with the surface and with the open jaws, means for supporting the tube in a receiving position axially aligned with one end of the cavity, a plunger aligned with the other end of the cavity and connected to a third actuator for reciprocal movement into and out of the cavity, and control means connected to the second, first and third actuators and arranged to operate them in sequence to move the platen to its jaw contact position, close the jaws and advance the plunger into the cavity to force the compressed sponge into the tube.

The adjoining surfaces of the fixed and movable jaws are of semi-cylindrical cross-section. To assist in locating the sponge within the apparatus prior to compression, there may be provided an upstanding guide plate spanning the space between the fixed jaw and the movable jaw in its open position and located approximately in contact with the ends of the jaws opposite to the tube, the plate being formed with a hole through which the plunger may pass into the cavity.

The apparatus may further comprise a magazine from which tubes are discharged seriatim to a ready position opposite the receiving position, and a transfer member connected to a fourth actuator for movement between a loading position where it receives the tube at the ready position and a delivery position corresponding to the sponge receiving position of the tube.

In a preferred arrangement portions of the surface define an opening through which filled tubes fall, and the control means is connected to the fourth actuator and is arranged to operate it in sequence with the third actuator.so that the transfer member is held in its delivery position when the plunger is moving into the cavity so as to support the tube during filling. The apparatus may then further comprise a member supported above the sponge receiving position of the tube and hinged to allow tubes to pass from the ready to the sponge receiving position during forward travel of the transfer member but to displace filled tubes from the transfer member during reverse travel thereof to fall through the opening.

The several actuators are conveniently doubleacting pneumatic rams and are conveniently operated in a forward direction by line pressure applied to their piston sides. The control means may include at least one valve connected to the exhaust side of one ram, controlling the admission of air to the piston side of the ram next following in sequence and arranged to respond to a predetermined fall in pressure at the exhaust side of said one ram whereby said rams are operated in cascade.

In a further aspect the invention provides a method for packing a sponge or like compressible body into a tube where it is held in compression, which comprises: flattening the sponge into a closed cavity defined by a fixed sponge receiving surface, a platen and a pair of opposed spaced jaws located between the platen and the surface; moving one jaw into abutment with the other so that the sponge is compressed into a cavity defined by adjoining concave surfaces of the jaws; and inserting the plunger from one end into the cavity so as to force the sponge into a tube held at the opposite end of the cavity in axial alignment therewith.

Conveniently the cavity defined on abutment of the jaws has a cross-sectional area about 10% less than that of the tube. For some applications it may be unnecessary to use a lubricant, but where high compression ratios are employed more reproducible results are obtained by coating the tube with a lubricant before the sponge is introduced into it.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a view in section of a tube in which a sponge is packed; Figure 2 is a plan of a sponge packing apparatus; Figure 3 is a transverse section of the apparatus in the vertical plane A-A of Figure 2; Figures 4 and 5 are transverse sections of the apparatus in the vertical plane B-B of Figure 2 with the tube transfer member in the loading and discharge position respectively; and Figure 6 is a circuit diagram of a pneumatic system which forms part of the apparatus of Figure 2.

In Figure 1 a tube 10 of cellulose acetate is packed at a cross-sectional compression ratio of about 8:1 with a rectangular slab 11 of a cellular polyurethane material intended to be used as a car cleaning sponge. When removed from the tube the sponge 11 returns to its original size in a short space of time. Portions of the tube 10 may be coloured or may bear printed information. The product is of small size and is of attractive appearance.

In Figures 2, 3 and 4 a table 20 or like sponge receiving surface has fixed to it a jaw 21 having a concave semi-cylindrical face 22. A movable jaw 23 having a second concave semi-cylindrical face 24 is connected to the rod 25 of a double-acting pneumatic ram 26. Extension of the rod 25 moves the jaw 23 over the table 20 from the jaw's open position illustrated to a position in which the jaws 21, 23 abut and faces 22 and 24 abut to define a cylindrical cavity for a compressed sponge. A plunger 27 is connected to a rod 28 of a doubleacting pneumatic plunger operating ram 29 with its line of action coinciding with the axis of the cavity defined by abutment of jaws 21 and 23.

Adjacent the end of the jaws 21 and 23 nearest ram 29 is provided an upstanding plate 30 formed with a hole 31 through which plunger 27 can enter the cavity on extension of the rod 28. A platen 32 is connected to the operating rod 33 of a ram 34 having a vertical line of action and overlies the jaws 21 and 23. The ram 34 is supported above the table 20 on frame members 35 which are formed with a vertical slot (not shown) in which a locating tongue 36 slides to maintain the platen 32 square in relation to jaws 21,23.

A feed plate 40 leads into a vertical tube magazine 45 defined by side walls 41 and 42 and end walls 43 and 44. A transfer member 46 has a raised apron 47 and a platform 48 terminating in a retaining lip 49. In the retracted position of the transfer member shown in Figure 4 the tubes 10 fall from the magazine 45 to the platform 48 which there are retained in a ready position. The transfer member 46 is connected to a rod 51 of a double-acting pneumatic ram 52. The rod 51 may be extended as shown in Figure 5 to move the transfer member 46 to a delivery position in which the tube 10 is axially aligned with the discharge end of the cylindrical cavity defined by jaws 21 and 23. The ram 52 is retained in its extended position during filling of a tube 10 so that the tube is held by platform 48 against falling through slot 50 in the table 20.During advance of the transfer member 46 the apron plate 47 blanks off the lower end of the tube magazine 45 and the tube 10 is pushed past an escapement plate 54 hinged at 45 to a support 56 on wall 42 of the magazine, the top of the tube passing beyond the escapement plate. When the rod 51 is retracted the filled tube 10 cannot pass the escapement plate 54 which displaces it from the platform 48 to fall through the slot.

In Figure 5 a main control valve 82 operated by start button 83 can either apply advance signals I (dotted line state) or retract signals II (solid line state). The piston and rod sides of ram 52 are connected through double-acting control valve 60 through lines 61 and 62. A pressure sensing valve is connected to the line on the rod side 62. On receipt of a ram advance signal I the valve 60 applies line pressure P through port A to piston side line 61 and rod side line 62 is vented through port B. When ram 52 nears the end of its stroke valve 63 which normally vents to atmosphere closes to supply the ram advance signal I through line 64 to one side of control valve 65. Lines 66 and 67 connect the piston and rod sides of ram 34 with the valve 65.On receipt of signal I valve 65 connects port B and line 66 to line pressure and vents port A and line 67 to atmosphere thereby extending rod 33. When ram 34 is close to full extension valve 68 which normally vents to atmosphere and is connected to line 67 through line 69 responds to a fall in pressure in the rod side of actuator 34 and sends a control signal I through line 70 to one side of valve 71 which is connected via lines 72 and 73 to the two sides of ram 26. A pressure sensitive control valve 74 communicates with rod side of ram 26 via line 75 and passes the ram advance signal I via line 76 to control valve 77 connected via lines 78 and 79 to the two sides of ram 29. The action of ram 34, valve 65 and valve 68 is repeated in ram 26, valve 71 and valve 74 and further repeated in ram 29 and valve 77. It follows that the control circuit operates in cascade manner to (i) extend the ram 52 and move a tube from the ready to the tube receiving position, (ii) extend ram 34 to flatten the sponge, (iii) extend ram 26 to compress the sponge and finally (iv) to extend ram 29 to inject the compressed sponge into the tube. Since the pressure in the rod side of each ram only falls sharply near the end of the stroke the valve 68 and 74 can be adjusted so that each ram substantially reaches the end of its travel before the next ram is tripped. Valve 80 senses fall in pressure at the rod side of the ram 29 near completion of its stroke and sends a signal to a main control valve 82 to change over from signals I (dotted lines) to signals II (solid lines). Valve 60 then returns to its rest state and ram 52 retracts. Signals II are also applied to valve 65, 71 and 77 to retract rams 34, 26 and 29 essentially simultaneously.

It will be appreciated that the apparatus described above is of simple and inexpensive construction but has been found to be highly effective for the mechanical packing of sponge into tube.

Claims (17)

1. Apparatus for packing a sponge or like compressible body into a tube where the sponge is held in compression comprising a surface for receiving the sponge, a fixed jaw on the surface and an opposed movable jaw connected to a first actuator for travel over the surface between an initial open position in which a sponge may be placed between the jaws and a closed position in which the jaws abut with adjoining concave surfaces thereof defining a cavity for the compressed sponge, a platen overlying the fixed jaw and the movable jaw throughout its travel and connected to a second actuator for movement normal to the surface between a position spaced from the jaws to allow sponge insertion and a position in contact with the jaws so that the sponge may be flattened into a closed space which the platen defines with the surface and with the open jaws, means for supporting the tube in a receiving position axially aligned with one end of the cavity, a plunger aligned with the other end of the cavity and connected to a third actuator for reciprocal movement into and out of the cavity, and control means connected to the second, first and third actuators and arranged to operate them in sequence to move the platen to its jaw contact position, close the jaws and advance the plunger into the cavity to force the compressed sponge into the tube.

2. Apparatus according to claim 1 wherein the adjoining surfaces of the fixed and movable jaws are of semi-cylindrical cross-section.

3. Apparatus according to claim 1 or 2 further comprising an upstanding guide plate spanning the space between the fixed jaw and the movable jaw in its open position and located approximately in contact with the ends of the jaws opposite to the tube, the plate being formed with a hole through which the plunger may pass into the cavity.

4. Apparatus according to any preceding claim, further comprising a magazine from which tubes are discharged seriatim to a ready position opposite the receiving position, and a transfer member connected to a fourth actuator for movement between a loading position where it receives the tube at the ready position and a delivery position corresponding to the sponge receiving position of the tube.

5. Apparatus according to claim 4 wherein portions of the surface beneath the sponge receiving position of the tube define an opening through which filled tubes fall, and the control means is connected to the fourth actuator and is arranged to operate it in sequence with the third actuator so that the transfer member is held in its delivery position when the plunger is moving into the cavity so as to support the tube during filling.

6. Apparatus according to claim 5, further comprising a member supported above the sponge receiving position of the tube and hinged to allow tubes to pass from the ready to the sponge receiving position during forward travel of the transfer member but to displace filled tubes from the transfer member during reverse travel thereof to fall through the opening.

7. Apparatus according to any preceding claim wherein the first, second, third and fourth actuators or any of them is or are a double-acting pneumatic ram.

8. Apparatus according to claim 7 wherein the actuators are operated in a forward direction by line pressure applied to their piston sides and the control means includes at least one valve connected to the exhaust side of one ram, controlling the admission of air to the piston side of the ram next following in sequence and arranged to respond to a predetermined fall in pressure at the exhaust side of said one ram whereby said rams are operated in cascade.

9. Apparatus for packing a sponge or like compressible body into a tube where the sponge is held in compression substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

1 0. A method for packing a sponge or like compressible body into a tube where it is held in compression, which comprises: flattening the sponge into a closed cavity defined by a fixed sponge receiving surface, a platen and a pair of opposed spaced jaws located between the platen and the surface; moving one jaw into abutment with the other so that the sponge is compressed into a cavity defined by adjoining concave surfaces of the jaws; and inserting the plunger from one end into the cavity so as to force the sponge into a tube held at the opposite end of the cavity in axial alignment therewith.

11. A method according to claim 10, wherein the sponge is compressed into a cavity of crosssectional area less than that of the tube.

12. A method according to claim 10 or 11 wherein the ratio of the cross-sectional area of the uncompressed sponge to that of the tube is from 4:1 to 12:1.

13. A method according to claim 12, wherein the ratio is from 6:1 to 8:1.

14. A method according to any of claims 10 to 13 wherein the tube is coated with a lubricant before the sponge is introduced.

1 5. A package comprising a body of resilient cellular synthetic plastics material held in compression within a tube, the cross-sectional area of the body in its uncompressed state being from 5 to 12 times that of the tube.

1 6. A package according to claim 1 5 wherein the cross-sectional area of the body in its uncompressed state is from 6 to 8 times that of the tube.

17. A package according to claim 1 5 or 16 wherein the body is a sponge of synthetic plastics material and the tube is of a transparent plastics material.