CA1043311A - Single piston operated clip device - Google Patents

Abstract

Abstract of the Disclosure An improved pneumatic circuit for sequentially controlling the se-parate main drive, clip feed and knife cylinders of a clipper mechanism as well as the means for blowing material from the die surface, including a two position pilot valve, operated by a mechanically actuated control valve and a time delay means, such as an adjustable orifice pilot valve.

Description

10433~
This invention relates to a control means for an improved clipper mechanism.
This application is a division of a co-pending parent, Canadian Application No. 230,549.
In the past, various patents have disclosed structure which provides a punch mechanism for driving a clip subsequent to gathering of material to be clipped and formation of a clip channel by a gate member. Such clipper mechanisms gather material to be clipped and hold the material in proximity to a clip die positioned in the path of travel of a clip driven by a punch.
The material gathering and displacement mechanism is generally a gate operated by an air cylinder. As the gate gathers the material, it simultaneously com-pletes formation of a channel for the clip.
A separate air cylinder generally operates the punch which drives the clip about the gathered material. Typical prior ar* patents disclosing such structure include Tipper, United States Patent No. 3,394,528, United States Patent No. 3,543,378 and United States Patent No. 2,880,419.
As stated above, the known prior art patents disclose formation of the channel for guiding the clip by closure of a gate which is effected by a mechanical or manually operated gate control mechanism separate from the drive mechanism for the clip punch. Such prior art apparatus does not generally disclose a mechanical linkage connecting a channel forming gate and a clip punch with the same drive cylinder.
The present invention consists of a clipper mechanism including a main fluid actuated drive cylinder for operating a clip punch and a separate fluid actuated knife cylinder for operating a cut-off knife, and cylinder control means including a single input fluid source to the opposite ends of said cylinders, said control means further including a two position main pilot valve, having a first normally pressurized position whereby pressur-ized fluid is directed from the source through a first outlet of the main pilot valve by parallel connections to the drive cylinder and the knife cylinder to maintain said cylinders in the punch retracted position and knife unoperated position respectively, and a second pressurized position whereby B

104331~
the first outlet is exhausted and fluid is directed from a second outlet of the main pilot valve to the opposite end of the drive cylinder and oy a separate parallel connection from the source to the opposite end of the knife cylinder to drive the drive cylinder to a punch extended position and the knife cylinder to the knife operated position respectively, said separ-ate parallelconnection from the source to the knife cylinder including a pilot operated knife control valve having a control inlet responsive to the outlet signal of a time delay diaphragm valve, said time delay diaphragm valve having a control port in parallel with the first position of said two position main pilot valve to positively maintain the diaphragm valve in a no outlet signal position during the first normally pressurized position of said two position pilot valve, said diaphragm valve also including re-stricted orifice time delay means for controlling the time of operation of the diaphragm valve when said two position main pilot valve is moved to the second pressurized position, whereby the knife cylinder operation is time delayed.
An object of the present invention is to provide an improved fluid control mechanism for operation of a clipper mechanism and, in partic-ular, the main drive cylinder of a clipper mechanism.
Other advantages and features will be set forth in greater detail in the description which follows.
In the detailed description of a preferred embodiment which follows, reference will be made to the drawings comprised of the following figures:
Figure 1 is a front perspective view of the improved clipper appara-tus or clipper of the present invention in combination with a clip feed mech-anism;
Figure 2 is an enlarged perspective view of the mechanical linkage and gate mechanism as well as the trigger mechanism associated with the im-proved clipper apparatus of the present invention;
Figure 3A is an enlarged partially schematic view of the lost motion linkage and punch drive linkage in the full upright or retracted position;

~ -2-~`

~043311 Figure 3B is a view similar to Figure 3A wherein the main drive cylinder has projected the punch partially toward the fully extended position;
Figure 3C is similar to Figures 3A an~ 3B and illustrates further extension of the main drive cylinder to the fully extended position;
Figure 4 is a schematic view of the pneumatic control circuit for the clipper of the present invention;
Figure 5 is an enlarged perspective view of the cutting knife asso--2a-ciated with the clipper apparatus of the present invention;
Figure 6 is a cross sectional view of the cutting blade associated with the cutting knife taken along the line 6--6 in Figure 5;
Figure 7 is a view of the channel forming member of the clipper of the present invention; and Figure 8 is an enlarged cross sectional view of the channel in the channel forming member taken along the line 8--8 in Figure 7 and illustrating the opening for ingress of clips to the channel for engagement by the punch.
Referring to Figure 1, the improved clipper apparatus of the present invention includes a bracket assembly comprised of a lower support plate 10 with a guide 12 mounted thereon. A C-shaped die support 14 defined by a vertical plate is attached to the guide 12 and extends upwardly from plate 10.
As illustrated in Figures 3 and 7, the die support 14 includes a grooved channel ~6 for receipt of a punch 18 and clip 20. The punch 18 drives clip 20 downward in channel 16 against a die or anvil 30.
The die support 14 is C-shaped and thus defines a throat opening 22 for receipt of gathered material about which the clip 20 is to be placed. A
gate 24 is pivotally attached by means of pin 26 through opening 28 to the die support 14. The gate 24 may thus be rotated to close the throat opening 22 and complete the grooved channel 16 as shown in Figure 3C. Alternatively, - the gate 24 may be rotated to its full open position as illustrated in Figures

2 and 3A for admission of material to the throat opening 22.
The die 30 is positioned in support 14 adjacent the lower end of chan-nel 16 in the manner known to those skilled in the art. The die 30 thus co-operates with the legs of a clip 20 to form those legs about material main-tained in the throat opening. The general method of clip 20 formation is also known to those skilled in the art.
First and second side gathering plates 32 and 34 are attached to the opposite sides of the gate 24. Plates 32, 34 assist in gathering and position-ing material placed in the throat opening 22 prior to attachment of a clip 20 10~3311 thereto. The apparatus thus far described is generally known to those skilled in the art.
A single main drive cylinder 36 is mounted on a bracket assembly 38 attached to the die support 14. The main cylinder 36 includes a projecting rod 40 extending from piston 122 in Figure 4, thereby defining a stroke of the clipper. When the rod 40 is in the position illustrated in Figure 3A, the clipper is in a retracted position. Extending the rod 40 to the position shown in Figure 3C, places the clipper in a fully projected or extended posi-tion. Actuation of the drive cylinder 36 and thus extension of the rod 40 causes punch 18 to be driven through grooved channel 16 against a clip 20.
Thereby, the clip 20 is formed against the die 30 and closes about material gathered in the throat opening 22 by the gate 24 and gathering plates 32 and 34.
Rod 40 is connected to a platen 42. Platen 42 is maintained in pro-per alignment by means of bushings 43 slidable on guide rods 44 fixed to the bracket assembly 38. Punch 18 is then attached to the opposite side of pla-ten 42 and moves in response to movement of platen 42 with respect to fixed guide rods 44.
Platen 42 includes an outward extension 46 having a downwardly pro-jecting post 48 attached thereto and movable therewith. Attached to the lower end of the post 48 is a cam actuator 50. The cam actuator 50 includes a cam track 52 having a horizontal first run 54 and a vertical second run 56. A
follower or link pin 58 attached to one end of a link 60 is positioned in the track 52 and projects into a cam slot 62 in a cam plate 64 attached to the bracket assembly 38. The follower or link pin 58 thus simultaneously follows the path defined by both cam tract 52 and cam slot 62.
The opposite end of link 60 is pivotally attached by pin 66 to the gate 24. Thus, the cam actuator 50, link 60 and gate 24 move in response to movement of platen 42. The movement imparted to the gate 24 is a pivotal mo-- 30 tion about pin 26. When the rod 40 is in its retracted or unextended position, ~043311 the gate 24 is open as illustrated in Figure 3A. When the rod 40 is in its extended position, the gate 24 is closed as illustrated in Figure 3C. Figure 3B illustrates an intermediate position of the platen 42 though the gate 24 has been almost fully rotated to a closed position.
Note that the relationship of track 52, slot 62 and follower 58 provides a lost motion action at the lower end of the stroke of rod 40. Thus, as the rod 40 is initially extended from the position of Figure 3A, follower 58 is maintained in first run 54 due to the cooperation of upper portion 68 of slot 62 on follower 58. As the rod 40 is extended to the position illu-strated by Figure 3B, the follower 58 is caused to travel from the first run 54 to the second run 56 of track 52 by action of segment 70 of cam slot 62 on follower 58. Segment 72 of cam slot 62 maintains the follower 58 within the second run 56 of slot 52. Segment 70 is an intermediate inclined segment of slot 62 and thus provides a gradual transition from run 54 to run 56.
Segment 70 is preferably inclined from the horizontal and may be constructed to define the lower end of slot 62 as discussed below.
When the follower 58 is in the second run 56, no further rotational motion is imparted by movement of platen 42 to the gate 24. In other words, any additional motion is accounted for by movement of follower 58 within second run 56. Note that slot 62 may include a lower segment 72 which accom-modates the lost motion action. Alternatively, the inclined segment 70 is tesigned to define the lower termination point of follower 58 in slot 62.
Follower 58 will then bottom at the end of segment 70 and remain in fixed position pending reversal of stroke of piston 122.
In this manner, the rod 40 may be extended to its full projected position, thereby fully actuating punch 18 subsequent to complete closing of gate 24. In other words, the gate 24 is initially and sequentially rotated into proper closed position (as shown in Figure 3B) prior to driving a clip 20 tightly about gathered material in the throat opening 22. Initial closing of gate 24 is necessary to form channel 16 for clip 20.

~0433~1 As discussed, a single main drive cylinder 36 is utilized to oper-ate both the punch 18 and gate 24. Both punch 18 and gate 24 are positively driven and positively withdrawn by operation of cylinder 36. That is, upon reversing the stroke of the main cylinder 36, the punch 18 is initially withdrawn. Subsequently, the gate 24 is positively rotated in the opposite direction to assume the position illustrated by Figure 3A.
Referring now to Figure 2, some additional important features of the improved clipper of the present invention are illustrated. As shown in that figure, a trigger 73 is attached to a rocker shaft 74 pivotally mounted on a trigger bracket 76. A lever arm extension 78 attached to the opposite end of shaft 74 is positioned to engage a limit switch arm 80 associated with an air limit switch or valve 82. Valve 82 includes an air inlet line 84 and an air outlet line 85, the function of which will also be described in further detail with reference to Figure 4 below.
Rotation of the lever arm extension 78 will actuate valve 82.
Lever arm extension 78 is rotated in response to movement of trigger 73 in the coun$erclockwise direction in Figure 2. This occurs whenever material to be clipped is placed within the throat opening 22 by an operator. For example, a plastic bag which is to be clipped would be pushed into the throat opening and, upon doing this, would also engage the trigger 73,thereby actuating the valve 82.
The trigger bracket 76 is unted on a lead screw 84. The opposite end of the bracket 76 includes a slot 86 which is engaged with a flange 88 on a fixed bracket 90. A trigger adjustment knob 92 in Figure 1 is mounted on the bracket assembly 38 and operates bevel gears 94 to thereby rotate lead screw 84. She lead screw upon rotation will move the trigger bracket 76 forward or backward depending -~pon the sense of rotation. In this manner, the trigger 73 is placed forward or back in the throat opening 22 and the triggering mechanism for the pneumatic circuitry described below can be adjusted.

104331~
Figures 2, 5 and 6 illustrate the knife cut-off mechanism asso-ciated with the improved clipper of the present invention. A knife support member 96 is pivotally attached to the die support 14. A knife blade 98 is removably inserted in a slot 100 provided. The blade 98 includes a spring member 102 which fits in an opening 104 of member 96 to retain the blade 98. Consequently, the blade 98 is removable upon flexure of the spring portion 102 from locking engagement with opening 104.
The opposite end of knife support member 96 is attached to a rod 106 extending from a knife operating cylinder 108. To operate the knife blade 98, the rod 106 is retracted thereby rotating the knife support 96 in the counterclockwise direction as illustrated in Figures 2 and 5. This causes the knife blade 98 to pass adjacent the throat opening 22 and the die 30, thereby cutting off any material projecting beyond the die 30.
Referring nOw to Figure 4, the method of operation of the improved clipper of the present inventiOn will be described. As previously recited, valve 82 controls the initiation of operation of the clipping mechanism.
Valve 82 is a control valve and provides an output through line 86 to a main pilot valve 110. When valve 82 is in the closed position, illustrated in Figure 4, pressurized air passes through input 112 of main pilot valve 110 and through outlet 114. Pressurized fluid through the line 114 or the first main outlet of the pilot valve 110 is directed in parallel fashion to inlet 116 of main drive cylinder 36 and to inlet 118 of the diaphragm pilot valve 120.
Pressure through inlet 116 acts against the lower side of piston 122 of main drive cylinder 36, thereby maintaining rod 40 in a retracted posi-tion as illustrated. Pressure through inlet 118 of diaphragm valve 120 acts on diaphragm 124 and valve member 126 so that pressurized fluid to the inlet 128 of valve 120 is not directed to any outlet. The outiet 114 is also con-nected to the inlet 128 of knife cylinder 108. Pressure acts on piston 107 and maintains the rod 106 of knife cylinder 108 in a projected position as illustrated in Figures 4 and 5.

~04331~
Upon actuation of arm 80 to open valve 82, pressurized fluid passes through line 86 and shifts valve member 130 of valve 110 to the right. Upon transfer of the valve member 130, pressurized air through inlet 112 then passes to the second outlet 132. First outlet 114 is now exhausted through exhaust outlet 134. Thus, the lower side of piston 122 is exhausted. Simi-larly, the top side of piston 107 associated with rod 106 is exhausted.
Pressure is also released from the top of diaphragm 124 associated with valve 120.
When the fluid pressure is provided through the second outlet 132, the piston 122 and associated rod 40 are immediately driven toward the ex-tended position. The operation of the punch 18 and gate 24 in response to movement of rod 40 is effected as previously described.
After some time delay, the valve member 126 shifts upward from the position illustrated in Figure 4 so that air pressure through inlet 128 may pass through outlet 136. This time delay is provided as a result of orifice 138 which permits air to leak into chamber 137 on the bottom side of diaphragm 124 at a slow rate thereby preventing immediate snap action of valve member 126. Preferably, the size of the orifice 138 is adjustable in order to set the time delay of valve member 126. This time delay is neces-sary in order to delay operation of the knife cylinder 108 until a clip 20 has been successfully attached to gathered material.
Subsequent passage of pressurized air from outlet 136 to inlet 140 of knife control valve 142 causes valve member 144 to be shifted permitting pressurized air from inlet 146 to pass through outlet 148. Pressurized air through the outlet 148 acts on lower side of piston 107, thereby retracting rod 106 and operating the knife blade 98.
The outlet 148 is also connected with pilot inlet 150 of valve 110 causing the pilot v&lve member 130 to be shifted back toward the original position illustrated in Figure 4. Shifting of valve member 130 thereby automatically reverses the operation since second outlet 132 then is exhausted.

through exhaust port 135.
Note that additional lines as at line 152 may be provided to effect further operations. For example, line 152 may be directed to a clip feeding assembly 154 in Figure 1 or a clip advance mechanism 156 in Figure l. Also, additional lines may be included in parallel with the first outlet 114.
For example, line 155 may be connected through a conduit to a clip blow out passage 157 in Figure 3A and 5. Such a clip blow out passage 157 provides air directly to the face of the die 30 to clean off the die face prior to attachment of additional clips.
While in the foregoing there has been set forth a preferred em-bodiment of the present invention, it is to be understood that the invention shall be limited only by the scope of the following claims and their equiva-lents.

Claims (3)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a clipper mechanism of the type including a main fluid actuated drive cylinder for operating a clip punch and a separate fluid actuated knife cylinder for operating a cut-off knife, the improvement comprising: cylinder control means including a single input fluid source to the opposite ends of said cylinders, said control means further including a two position main pilot valve, having a first normally pressurized position whereby pressurized fluid is directed from the source through a first outlet of the main pilot valve by parallel connections to the drive cylinder and the knife cylinder to maintain said cylinders in the punch retracted position and knife unoperated position respectively, and a second pressurized position whereby the first outlet is exhausted and fluid is directed from a second outlet of the main pilot valve to the opposite end of the drive cylinder and by a separate parallel connection from the source to the opposite end of the knife cylinder to drive the drive cylinder to a punch extended position and the knife cylinder to the knife operated position respectively, said separate parallel connection from the source to the knife cylinder including a pilot operated knife control valve having a control inlet responsive to the outlet signal of a time delay diaphragm valve, said time delay diaphragm valve having a control port in parallel with the first position of said two position main pilot valve to positively maintain the diaphragm valve in a no outlet signal position during the first normally pressurized position of said two position pilot valve, said diaphragm valve also including restricted orifice time delay means for controlling the time of operation of the diaphragm valve when said two position main pilot valve is moved to the second pressurized position, whereby the knife cylinder operation is time delayed.

2. The improvement of Claim 1 including a parallel fluid connection from the knife control valve outlet to a separate fluid operated clip feel mechanism for the clipper.

3. The improvement of Claim 1 including a parallel fluid connection from the first outlet of the two position pilot valve to a die of the clipper mechanism for blowing material from the die surface.