US 3251295 A
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y 17, 1966 c. e. DICKENS ET AL STRAP FEEDING APPARATUS 5 Sheets-Sheet 1 Filed Nov. 12, 1964 y 17, 1956 c. G. DICKENS ET AL 3,251,295
STRAP FEEDING APPARATUS 5 Sheets-Sheet 2 Filed Nov. 12, 1964 y 1966 c. G. DICKENS ETAL 3,251,295
STRAP FEEDING APPARATUS Filed Nov. 12, 1964 3 Sheets-Sheei 5 United States Pat 3,251,295 STRAP FEEDING APPARATUS Charles Garth Dickens, Saratoga, and Terence H. West, Santa Clara, Calif., assignors to FMC Corporation, Philadelphia, Pa, a corporation of Delaware Filed Nov. 12, 1964, Ser. No. 410,414 8 Claims. (Cl. 100-8) The present invention relates to apparatus for facilitating the strapping of bundles or articles and especially to apparatus for drawing a flexible strap about a relatively large package to thus position the strap for convenient manual securement. More particularly, the invention relates to apparatus for lacing a flexible strap through a load supporting pallet and part way about the load resting on the pallet.
To facilitate the movement of large loads by fork lift trucks, it is common practice to provide a load supporting pallet and to strap the load to the pallet whether the load consist of a single large object such as a carton or a multiplicity of smaller objects. Some pallets have a single face or floor supported on short post-like legs or longitudinal runners and others have two faces spaced apart sufliciently to permit the tines of the fork lift truck to enter therebetween. When double-face pallets are used it is desirable to have the straps pass through the space between the two faces of the pallet so that the straps will not interfere with or be damaged by the insertion of the tines of the fork lift truck through the pallet.
Steel straps and certain types of plastic straps have sufficient stiffness to permit the free end to be moved forward by pushing, as by means of feed rollers, on a remote portion of the strap. Such straps may be fed through a double-faced pallet by pushing the strap along a guide tracks which is inserted through the pallet after the pallet and its load have been moved into strapping position. One form of mechanism for semi-automatically strapping a load to a double-faced pallet with steel straps v is shown in US. Patent No. 2,985,098 to Winkler.
In the US. Patent No. 3,028,281 to Karass there is described a form of strap known as cord strapping which lacks the stiffness of steel straps and which cannot readily be pushed. Because of its limpness or lack of stitfness, cord strapping is normally positioned about the article by gripping the free end and pulling the strap thereabout. A form of apparatus for permitting semi-automatic strapping of a load to a double-faced pallet with cord strapping is shown in US. Patent No. 3,152,539 to Sorensen. The present invention is primarily directed to apparatus for use with limp strapping and constitutes an improvement over the apparatus of the Sorensen patent.
It is an object of this invention to provide an improved apparatus for pulling a flexible strap through a doublefaced pallet and at least part way about a load resting on the pallet.
Further and more specific-objects of the invention as Well as the means for attaining the same will become apparent as the description of a preferred embodiment thereof proceeds.
Referring now to the drawings:
FIG. 1 is a side elevational view of the apparatus;
FIG. 2 is a sectional view taken along the line II--II of FIG. 1;
FIG. 3 is a section view of a chain guiding element or lance constituting one of the parts of the apparatus;
FIG. 4 is a side elevatio-nal view, partially in section, of a chain locking mechanism;
FIG. 5 is a front elevational view showing a carrier for permitting attachment of the end of a strap to the endless chain;
3,25LZ95 Patented May 17, 19%6 FIG. 6 is a side elevational view showing the manner of attaching the strap to the chain;
FIG. 7 is a schematic showing of the pneumatic system of the apparatus;
FIG. 8 is a wiring diagram of the electrical system; and
FIGS. 9 and 10 are diagrammatic side elevational views of the apparatus.
The invention is illustrated as incorporated in a press but it will become apparent that its general utility is notlimited to such an environment. The: illustrated apparatus comprises a framework including a base generally designated at 10 from which rises a pair of columns 12, only one of which is shown. Opposite edges of each column 12 provide tracks for guiding rollers 14!- and 16 carried by frame members 18, only one of which is shown. Frame members 18 support in cantilever a pressure platen generally designated at 20. Any suitable means, such as an hydraulic cylinder, acting on frame members 18 may be employed for moving platen 20 up and down.
Base 10 includes a plurality of members 22 which extends horizontally beneath platen 20 and rollers 24 of a roller conveyor have their upper surfaces spaced above members 22 whereby the load to be strapped may be conveniently moved into the strapping station beneath the platen.
Referring to FIGS. 1 and 2, a support 25 extends upwards from base 10 and has secured therein a plurality of axles or shafts, two of which, 2s and 28 are shown in FIG. 2. Mounted for free rotation on shaft 26 is a double-flanged wheel 30 and a similar Wheel 32 is rotatably mounted on shaft 28. Two other shafts or axles 34 and 36 (see FIG. 1) are secured in support 25 and these carry flanged wheels, not shown, similar to wheels 30 and 32. A carriage or lance 3 is supported between the wheels 36 and 32 and the other pair of wheels carried by shaft 34- and 36 whereby said lance may be reciprocated between an extended position shown in FIG. 1 and a retracted position extending leftwardly of column 12, as will presently be explained.
Chain guiding sprockets 4.0, 42, 44 and as are mounted for free rotation on shafts 26, 28, 34 and 36 respectively. A pair of freely rotatable sprockets 48? and 50 are mounted on the base 10 below the level of lance 38 and a pair of sprockets 52 and 54 are mounted near the top of column 12, sprocket 52 being freely rotatable and sprocket 54- having drivingly secured thereto a larger sprocket 56 by means of which sprocket 54 may be driven in opposite directions. Frame member 18 has a pair of freely rotatable sprockets 58 and 60 mounted thereon and a sprocket 62 is rotatably mounted on. the outboard end of pressure platen or arm 20. There is also a freely rotatable chain sprocket at each end of lance 38, the one at the right being indicated at 64 and the one at the left at 66. An endless roller chain 68 is trained about the various sprockets (except of course sprocket 56) in the manner indicated in FIGS. 1, 9 and 10. Sprocket 56 is connected through a roller chain 70 to a reversible air motor 72 wherebychain 68 may be selectively driven in opposite directions, as will presently be explained.
As previously indicated, the apparatus is primarily intended for pulling the end of a limp flexible strap through a pallet and part way about a load resting on the pallet. Straps of this nature may be secured about the load by crimping a metal sleeve about the overlapping strap portions after the strap is pulled tight or may be secured by a suitable buckle, as for example the buckle shown in Patent No. 3,014,256 to Derrickson et a1. When using a buckle it is convenient to be able to lace the strap through one side of the buckle before the strapping operation actually gets underway and then to use the buckle for attaching the strap to the endless chain. In FIGS. 5 and 6, a strap carrier is shown which permits easy attachment of the buckle of the Derrickson et al. patent to the chain, the buckle being indicated at 73. The carrier, generally designated 74, comprises an angle member 86 one arm of which is secured to the chain 6 as a replacement for one of the usual roller chain side plates and the other arm of which extends outwardly away from the side of the chain. Secured to or formed integrally with the outwardly directed arm of angle member 76 is a block 78 having a protruding rib 80. In attaching the limp strap 82 to the carrier the strap is first laced through one side of the buckle and the laced side of the buckle is slipped over rib 80. The buckle is then rocked clockwise so as to engage the other side thereof with the forward face of block 78 as indicated in FIG. 6. Of course block 73 is made of such size that the buckle will fit fairly snugly so that it will not slip off when the chain is driven as will be explained. The particular construction of carrier 74 is not of the essence of the present invention and it will be understood that any suitable means for permitting easy attachment of the strap to the chain may be employed.
Before describing the mechanisms by means of which the desired operation of the apparatus is achieved, attention is now directed to FIGS. 9 and 10 for an explanation of the overall operation. A load 34 resting on a doublefaced pallet 86 is moved along the roller conveyor 24 into the strapping station beneath the platen 2t}, lance 38 at this time being in retracted position as indicated in FIG. 9
and the strap carrier 74 being positioned near the outer end of the platen. Air motor 72 is then run in the direction to drive chain 68 in the direction of the arrow in FIG.
9 and at the same time the chain is locked as indicated at 88 at some point beneath lance 38. Since the chain cannot move in the vicinity of lock 88, the pull of the chain on sprocket "66 is effective to drive lance 38 toward the right so as to extend through pallet 86 as shown in FIG. 10, the pallet being aligned with the lance when the load is in the strapping position. Whein the lance reaches its fully extended position, lock 88 is automatically released and the entire chain continues to move until the strap carrier 74 reaches a position adjacent the outer end of the lance, at which time motor 72 is stopped. The operator then attaches the end of the strap to carrier 74 as aforesaid and starts air motor 72 running in the opposite di rection, this is, the direction to drive chain 68 in the direction of the arrows in FIG. 10. As the chain starts to move, .lock 88 is again applied whereby the pull of the chain about sprocket 64 is effective to move lance 38 back to the FIG. 9 position. When the lance reaches its fully retracted position, the carrier 74 will not have reached its FIG. 9 position but lock 88 is automatically released, permitting the entire chain to move until the carrier reaches the FIG. 9 position, whereupon motor 72 is stopped. The carrier has now dragged the flexible strap through the pallet and about three sides of the load, whereupon the operator disconnects the strap (with the buckle attached thereto) and pulls the end down to where the strap from the supply may be conveniently joined to the buckle to secure the strap about the load.
Chain lock 88 is shown in FIGS. 1 and 4 and comprises a bracket 90 suitably mounted on the base 10. Bracket 90 is provided with guide slots 92 to slidably accommodate a pin 94 secured to a locking member 96 which is connected to the piston 98 of an air cylinder 1W. Memnear its outer end. Within slot rides a pin 112 secured to one end of a latch lever 114 rockably mounted at 116 on the bracket 25. The other end of latch lever 114 is arranged to engage a vertical face of a wedge-like member 118 secured to the side of lance 38 to prevent accidental retraction of the lance while the operator is attaching the strap to carrier 74. A spring 120 acting on the latch lever normally holds it in the position shown in FIG. 1 and upon admission of air to cylinder 106 said lever is rocked clockwise to free member 118 and permit the lance to retract. As will be explained, as the lance nears the end of its retractive movement, air pressure is removed from cylinder 106 so that latch lever 114 is restored to the FIG. 1 position. There is a second wedge-like member 122 secured to the lance and when this member reaches latch lever 114 it cams said lever clockwise against the action of spring 120, this action being permitted by the slot 110 in the piston of air cylinder 106. When member 122 passes by the endof the latch lever, the lever snaps down to engage the vertical face of member 122 to thereby hold the lance in retracted position. The fully retracted position of the lance is determined by abutment of a lug 123 on the forward end of the lance against a lug 125 provided on the stationary framework. The fully extended position of lance 38 is determined by abutment of a lug 124 on the lance against a lug 126 provided on the stationary framework.
As shown in FIG. 3, the main body of the lance or chain guiding member 38 is in the form of a rectangular closed channel member the upper face of which is provided with a pair of slots 128 and 130, see also FIG. 1. An operating arm 132 of a limit switch IS1 extends into slot 128 when the lance is in the fully extended position and into slot 130 when the lance is in fully retracted position. Slots 128 and 130 are both long enough so that the switch operating arm is able to move thereinto a short time before the lance reaches its limit of movement but during most of the lance movement the end of arm 132 rides on the top face of the lance. When arm 132 is in either slot 128 or 131) limit switch LS-1 is open and when it is riding the top face of the lance the limit switch is closed. Limit switch LS-l partially controls the operation of chain lock 88 and latch lever 114, as will be explained.
Mounted near the end of lance 38 is a limit switch LS-2 having an operating arm extending into the path of movement of strap carrier 74 and a limit switch LS3 near the outer end of platen 20 also has an operating arm extending into the path of movement of the strap carrier. The limit switches LS2 and LS-3 are normally closed but when opened by the strap carrier are effective to stop the air motor 72 and the endless chain 68.
Referring to FIGS. 7 and 8, the control system shown therein diagrammatically will now be explained, it being assumed that the lance 38 is in the retracted position as shown in FIG. 9 and the strap carrier '74 is in the home position near the outer end of platen 20. With the load to be strapped properly positioned in the strapping station, the operator depresses a conveniently located button to close an electrical circuit to a relay CR1 which through a set of contacts 142 closes the circuit to a solenoid 144. Solenoid 144 operates a valve 146 to admit air from a main air line 148 through a line 150 to the air motor 72. This drives the air motor in the direction to cause the endless chain 68 to move in the direction of the arrow in FIG. 9 air from the motor exhausting through a line 152 and a passageway in valve 146. Depressing button 140 also closes a circuit through lines 154, 156 and 158 to a solenoid 160 and through line 154 a circuit to a relay CR-2 having a set of contacts M2 in the line 158. Energization of solenoid 160 opens a normally closed valve 164 to admit air from the line 148 through a line 166 to the air cylinders 100 and 106. Cylinder 101) operates the chain lock 88, whereby movement of the chain iselfective to extend the lance 38 through pallet 86 as aforesaid. When the lance is in the fully retracted position limit switch LS-l is open because the operating lever 132 therefor extends into the slot 130 but as soon as the lance moves a short distance the lever 132 rides out of the slot thereby closing limit switch LS-1 to main tain the circuit through relay contacts 162 and line v158 to the solenoid 160 after the operator releases the button 140. When the lance reaches the fully extended position, lever 132 drops into lance slot 128 to thereby open limit switch LS-l and de-energize solenoid 160. This permits valve 164 to close and connect air cylinder 100 to the exhaust whereby chain lock 88 is released. The chain continues to be driven by air motor 72 until the strap carrier 74 opens limit switch LS2 at the end of the lance to thereby de-energize solenoid 144 and close olT valve 146, whereupon the chain stops with the strap carrier in position at the end of the lance.
After attaching the strap to the carrier 74 as aforesaid, the operator depresses a button 168 to close a circuit to a relay CR3 having a pair of contacts 170 ina line 172 leading to a solenoid 174 and a pair of holding contacts 176 in a line 178 containing limit switch LS-3 located near the outer end of platen 20. Solenoid 174 operates valve 146 in a way to connect line 152 to the main air line 148 and the line 150 to the exhaust. The air motor 72 therefore begins to drive chain 68 in the direction of the arrows in FIG. 10. Operation of button 168 also closes a circuit through a line 180 and the lines 154, 156
and 158 to the solenoid 160 to activate air cylinders 100 and 106 and likewise closes a circuit through lines 184) and 154 to the relay CR-2. Air cylinder 100 operates the chain lock 88 and air cylinder 106 rocks latch lever 144 clockwise to release the stop 118 and free the lance for retractive movement. As soon as the lance moves a short distance, limit switch LS-l is closed as previously explained to thereby maintain the circuit to solenoid 160 after the button 168 is released. As the lance approaches its fully retracted position, switch operating arm 132 drops into lance slot 130 thereby opening limit switch LS-l and de-energizing solenoid 160. Air pressure is thereby relieved in cylinders 100 and 106 to release chain lock 88 and permit latch lever 114 to be restored to a position to engage the wedge-like member 122. The chain continues to move until carrier 74 engages the operating arm of limit switch LS-3 to thereby open the circuit to relay CR-3 and consequently the circuit to solenoid 174. Upon de-cnergization of solenoid 174 valve 146 closes and the air motor 72 stops with the result that the strap carrier comes to rest at the outer end of platen 20.
While the apparatus has thus far been described in connection with its utility for strapping a load to a doublefaced pallet, it is believed that it will be apparent that it may be used for strapping a load to a single-faced pallet or a load which is not resting on any pallet at all. In this case of course the lance is maintained in the retracted position and the strap carrier 74 is brought to rest through suitable controls along the upper run of chain 68 in the vicinity of sprocket 50 at the outer end of base frame member 22. This places the carrier in position for dragging the strap beneath the load resting on conveyor rollers 24. It will also be apparent that if desired the strap may be attached to the carrier 74 when the carrier is at the outer end of platen 20 whereby the strap may be dragged counterclockwise instead of clockwise as heretofore described.
Having thus described a preferred embodiment of the invention, what is claimed is:
1. Apparatus for lacing a flexible strap through a pallet and about a load resting on the pallet, said apparatus comprising a strapping station, means for supporting a pallet and its load in the strapping station, a lance mounted for horizontal movement between a first position removed from the strapping station and asecond position extending through the pallet supported in the strapping station, an endless chain, sprockets supporting said chain for movement along said lance, vertically adjacent said strapping means effective to cause movement of said chain in one direction to move said lance to its said second position, and said last named means being effective to cause movement of said lance to its said first position when the chain is moved in the opposite direction.
2. Apparatus for lacing a flexible strap through a pallet and about a load resting on the pallet, said apparatus comprising means for supporting a pallet and its load in strapping position, a lance mounted for horizontal movement between a position outside the confines of the pallet and a position extending through the pallet, an endless chain having a pair of substantially parallel runs extending above said lance and a pair of substantially parallel runs extending below the plane of movement of the lance, chain sprockets mounted on said lance near each end thereof,
said chain being trained about said sprockets, means for driving one of the runs of one of the pairs of runs of the chain in opposite directions, lock means for preventing movement of one of the runs of the other pair of runs of the chain whereby movement of said one of the runs of said one of the pairs of runs of the chain serves to move said lance, the direction of movement of the lance depending upon the direction of movement of said one of the runs of said one of the pairs of runs of the chain.
3. The apparatus set forth in claim 2 comprising sprockets about which said endless chain is trained to provide a pair of runsof the chain extending horizontally above the load.
4. Apparatus for lacing a flexible strap through a pallet and about a load resting on the pallet, said apparatus comprising a strapping station, means for supporting a pallet and its load in the strapping station,'a vertical standard alongside said strapping station, an arm extending cantilever from said standard above the strapping station, a lance mounted for horizontal movement be tween a first position removed from the strapping station and a second position extending through a pallet located in the strapping station, an endless chain, means directing said chain along said standard and said arm to provide upper runs of the chain, means directing said chain beneath said strapping station to provide lower runs of the chain, chain sprockets mounted on said lance near each end thereof, said chain being trained about said sprockets, drive means for driving the upper runs of said chain in opposite directions, lock means for preventing movement of the lower runs of said chain whereby movement of the upper runs of the chain is effective to move said lance between its said first and second positions, the direction of movement of the lance depending upon the direction of movement of the upper runs of the chain.
5. The apparatus set forth in claim 4 comprising manually operable means for applying said lock means, and means operable by said lance for releasing said lock means when said lance reaches its first. and second positions.
6. The apparatus set forth in claim 4'comprising a strap carrier secured to said chain, manually operable means for starting said drive means, means operable by said strap carrier for stopping said drive means when said strap carrier is moved to the end of said arm, and means operable by said strap carrier to stop said drive means when said strap carrier reaches the end of said lance when said lance is in its second position.
7. The apparatus set forth in claim 4 comprising a strap carrier secured to said endless chain, said strap carrier having a first home position at the outer end of said arm and a second home position at the end of said lance when the lance is in its second position, manually operable means for starting said drive means and for applying said lock means, automatically operable means for releasing said lock means when said lance reaches its first 3,251,295 7 V v .8 a and second positions, and automatically operable means References Cited by the Examiner for stopping said drive means when said strap carrier UNITED STATES PATENTS reaches either of its home positions.
8. The apparatus set forth in claim 7 wherein said g;fiz ggg""7 n lance operates said first mentioned automatically oper- 5 3159539 10/1964 Sorensen able means, and said strap carrier operates said second mentioned automatically operable means. WALTER A. SCHEEL, Primary Examiner.