US2777344A - Box strapping tool - Google Patents

Description

Jan. 15, 1957 Filed Oct. 26, 1953 H. A. SMITH BOX STRAPPING TOOL S Sheets-Sheet 1 INVENTOR. HARRY A. SM/TH TORNEYJ 7 1957v 7 I H. A. SMITH 2,777,344

BOX STRAPPING TOOL Filed Oct. 26, 1953 F/GS 5 SheetsSheet 2 INVENTOR. HARRY A. JM/TH A ORNEYJ Jan. 15, 1957 Filed Oct. 26, 1955 H. A. SMITH 2,777,344

BOX STRAPPING FOOL 3 Sheets-Sheet 3 INVENTOR.

HAPPY A .SM/ TH BY l TTORNE Y5 BOX STRAPPING TOOL Harry A. Smith, Middletown, Conn., assignor to The Stanley Works, New Britain, Conn., a corporation of Connecticut Application October 26, 1953, Serial No. 388,409

6 Claims. (Cl. 81-9.1)

The present invention relates to an improved box strapping tool for tensioning and sealing metal straps about boxes, packages and the like, and more particularly to such a tool employing a magazine for carrying a stack of seals, and having improved means for jamproof feeding of the seals from the magazine to the sealing mechanism.

It is an object of the present invention to provide a box strapping tool of the aforesaid type wherein accidental feeding of seals from the magazine is substantially preeluded.

Another object is to provide a box strapping tool of the aforesaid type having a sealing mechanism operated by means of a single control handle, wherein the means for feeding seals to the sealing mechanism can be operated only by a deliberate excursion of the control handle through its full displacement.

Another object of the present invention is to provide a box strapping tool of the aforesaid type, so constructed and arranged that only a single seal feeding operation can take place during any one strap sealing cycle.

Another object is to provide a box strapping tool of the aforesaid type wherein means isprovided to insure that only one seal can be extracted from the magazine and delivered to the sealing mechanism during a single sealing cycle.

Another object is to provide an improved box strapping tool of the aforesaid type in which the means for feeding seals from the magazine to the sealing mechanism can be operated only in response to a concurrent operation of the sealing mechanism to deform and discharge any seals therein.

Another object is to provide a box strapping tool of the aforesaid type having improved means for automatically aligning the strapping material therein.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the drawings:

Figure 1 is a side view of a box strapping tool constructed in accordance with the present invention, showing its disposition relative to an article to be strapped, and showing the general organization of certain of the operating parts thereof;

Fig. 2 is a view similar to Fig. l with certain exterior portions of the tool cut away to expose additional operating parts thereof;

Fig. 3 is an enlarged view of the tool showing the side opposite to that shown in Figs. 1 and 2, and also partially cut away to show details of certain of the internal parts;

Fig. 4 is a sectional view taken on the line 4--4 of Fig. 3;

Fig. 5 is an enlarged view of the side of the tool shown nited States Patent 0 "ice in Figs. 1 and 2, cut away to show additional details of the internal structure of the tool; and

Fig. 6 is a sectional view of the tool shown in Fig. 5, taken on the line 6-6 thereof.

Referring to the drawings, wherein like reference characters denote like parts in the several views, a box strapping tool constructed in accordance with the present invention includes a frame 2 which carries a strap tensioning mechanism 4, a strap sealing mechanism 6, a seal magazine 8, a seal feeding mechanism 10, and a single sealing handle 12 for manually controlling the operation of the sealing mechanism 6, and in association with it the operation of the seal feeding mechanism 10.

The frame 2 is provided with a base 14, including a plurality of laterally extending feet 16, 18 which are adapted to rest, as shown in Fig. 1, on the box or article to be strapped. Above and adjacent one of the feet 16 there is provided in the frame 2 a strap receiving and aligning channel 20 through which the free end of the strapping material carried on an adjacent supply reel or spool, not shown, is fed before being passed around the box. A sufiicient length of strap is passed through this channel 20 to encircle the box, and the free end is then passed through another aligned channel 22 provided adjacent the other foot 18. On the first foot 16 is a shoulder 24 against which the free end of the strap is adapted to abut to insure adequate overlap of the strap for a proper sealing operation.

On the forward part of the frame 2 there is provided a strap tensioning mechanism 4 which includes a shaft 26 journaled in a trunnion 28 which is pivotally mounted in the frame on another shaft 30. The shaft 26 carries at one end, as shown in Fig. l, the usual strap tightening wheel 32 having peripheral teeth 34 aligned with the strap receiving channel 20, and adapted to engage the strap and draw it tight about the box. Connected to the trunnion 28 is a downwardly extending strap guide 36 which assists in aligning the strap in the channel 20.

On the other end of the shaft 26 is mounted the tensioning handle 38, the manual operation of which in a clockwise direction, as shown in Fig. 1, rotates the tightening wheel 32 and tensions the strap. The connection between the handle and the shaft 26 carrying the tightening wheel 32 is of the usual ratchet and pawl type, not shown, so as to prevent retrograde movement of the tightening wheel 32 and loss of tension in the strap.

A spring 40 acting between the frame 2 and the trunnion 28 provides a strong bias of the trunnion 28 counterclockwise, as shown in Fig. 1, so as to urge the tightening wheel 32 normally into engagement with a strap in the channel 21}. However, the spring 40 is made of such a strength that, when the tensioning handle 38 has been depressed far enough to provide adequate tension in the strap, further depression of the tensioning handle 38 pivots the entire tightening wheel 32, shaft 26 and trunnion assembly about the shaft 30, and thus disengages the tightening wheel 32 from the strap in the channel 20. This has the dual purpose of preventing excessive tightening of the strap which might cause strap failure, and of enabling release of the strap from the tool after a box strapping operation has been completed.

Rearwardly of the strap tensioning mechanism 4 there is provided on the frame adjacent the second strap aligning channel 22 a strap engaging dog 42 pivotally mounted at 44 and urged by a biasing spring 46 clockwise, as

shown in Fig. 5, into strap engaging relation with the strap aligning channel 22. Depending from the bottom face 48 of the dog 42 are a plurality of strap engaging teeth 50, which are positioned forward of a perpendicular from the strap through the axis of rotation of the dog 42, so that, as the strap is tensioned, any slippage of the cams 1%, 163 have respective coaxial shanks strap will tend to rotate the dog 42 further clockwise, as shown in Pig. 5, and more securely engage the teeth 55 with Silfi1 When the f ee end of the strap is being passed about the box and being fed through the channel 22, the dog may be raised clear of the channel by actuation of a lever 52 which is provided at its outer end with a manual depression key 5 Carried by the dog 42 is one-half of a shear 56, the other half of which is carried by the sealing mechanism 5, as will later be described, for severing the box encompassing portion of the strap from the supply reel.

The upper face of the lateral foot 's provided with a slight slope or inclination relative to the lower face 4-8 of the dog. and these two opposed faces thereby form a tapered channel or slot, the apex of which is disposed adjacent the strap receiving channel 22. This tapered slot acts in the manner of a funnel and assists in guiding the strap into the channel 22. Also projecting from the lower face 4% of the dog 42-, to one side of the teeth 5d and opp e the inclined face of the foot 1 :3, is a strap alignin" mer er Tl 5: foot 18 is provided with a recessed portion into which the strap aligning member 60 is received when the dog 4-2 is pivoted into engagement with the strap.

The function of the strap aligning member 60 is twofold. if strap is not properly aligned in the channel 22, so that part of the strap extends beyond the side of the channel and rests on inclined face 58 of foot 13, when depression key 54 is released and dog 4?; descends toward the strap, stra aligning member 69 will engage the strap before teeth h... of dog and thereby prevent locking engagement of the dog teeth 56 with the strap. This permits the strap to be slid beneath dog 42 during the strap tightening operation, and during such sliding of the strap aligning member 6% performs its second function by assisting in camming the strap completely into channel 22. When the strap is properly aligned in channel 22 it no longer engages strap aligning member 60, and thereby dog 42. is permitted to descend fully and engage teeth 50 with the strap.

The seal magazine 8 consists of a vertical arcuatc element 70, disposed on the forward part of the frame, and formed of hollow rectangular cross section. The upper end of element 752 may be conveniently formed into a handle '72. for carrying the tool. The seals in the megazine 8 are of generally channel or inverted U-shape in cross section and have sloping sides so as to be carried in loosely nested relation in the magazine 8.

The sealing mechanism 6 includes a pair of arms 74 '76 pivotally supported in the frame at 78 and carrying the scaling jaw assembly till. Arms 74, 76 are biased upwardly to a rest position, as shown in Figure 2, by spring 82. The sealing jaw assembly 80 is of the usual double pivoted toggle type, having jaws 86 which are normally biased to an open position by springs 83 which embrace the jaw assembly. in operation in the usual manner, the jaws 86 in closing fold or deform the sides of a seal inwardly under the top of seal. This reduces the width of the seal so that when the jaws 35 are opened, they can be withdrawn from about the scaled strap or, in the absence of a strap, the deformed seal will fall out of the jaw assembly 80. To the upper portion of the jaw assembly 80 is connected 0. link 92 which is slidably secured by pin 92 and slot 94 to a lever 96. One end of lever 96 is pinned on a shaft 98 journalcd in the frame 2.

The other end of lever 96 is fastened by means of a strap 1% to the outer ends of a pair of transversely spaced cranks 102, ill-i, each of which is supported on one of a pair of spaced cams 2.06, 108. The two spaced 116*, 112 projecting from their outer sides which rotatably support the assembled cams lids, 16-3 and cranks 107;, 104 in the frame 2 for rotation about axis 116. The cams 1G6, 168 are of generally semicircular shape and coast with cam followers 12@ on the sides of the respective arms 74, "1'6 for depression of the arms and the sealing jaw assembly 'side of the magazine 3.

4 30 carried by them. Rotation of the cams 1G6, 163 and the cranks N2, 10 is accomplished by means of the sealing handle 12, which is secured to the shank 1 0 on the opposite side of the tool from the tensioning handle 38.

The initial or rest position of the sealing handle 12, corresponding to the rest position of the sealing mechanism 6, is, as shown in Fi ure 2, at the front of the tool. The handle 12 is maintained in this position against a stop member, not shown, by means of the spring 33L, one end of which is pinned to one of the arms "/6 and the other end of which is secured to the shank ill on the opposite side of the frame from the sealing handle 12..

To operate the sealing mechanism 6, the scaling handle 12 is rotated from its position at the front of the tool, as shown in Figure 2, to a substantially diametrically opposite position at the back of. the tool. The resulting rotation of the cams 3G6, 103 first depresses arms 74, '76 and dis places the scaling jaw assembly from its rest position down to its operative position in engagement with the top of the box between the feet i6, 18, in which position the jaws 36 embrace the overlapped portion of the strap. On the rear face of the jaw assembly is a shear 132 which coacts with sheer 56 on dog 42 to sever the box encircling strap portion from its supply reel as the jaw assembly 30 descends to its operative position.

Further rotation of earns 1.06, 103 as the sealing lever 12 is rotated through the remainder of its nrcunte displacement thereafter serves merely to rotate lever 96 about shaft 98 by means of cranks 182, M4 far enough to bottom pin 92 in slot 94- and depress the upper portion of jaw assembly 89 relative to the jaws 86. This relative motion actuates the toggle linkage in the jaw assembly and squeezes the strap ends together. A seal carried in the jaw assembly 8%) between jaws 86 will thereby be deformed about the overlapped portion of the strap, thus securing the tensioned strap about the box in the usual manner.

The seal feeding mechanism 16) includes a seal feeding member or pusher 146 which is formed with slots 148 adapted for sliding engagement in a track 15% formed by a pair of opposed flanges 1512 supported from the lower Pivotally connected its its lower end to the seal feeding member or pusher 146 is an actuating and latching link which is supported at its other end on shaft 98 for rotation and limited sliding movc- "lent. For this purpose the link 34% is provided with an L-shapcd slot l l-l having a longitudinal leg M2 and a transverse leg M4 in which the end of the shaft 93 is are-- commodated. The lower end of lever M0 and the seal pusher 146 are urged rearwardly of track 150 by spring 154, which is connected at 256 to frame 2. When in its rearmost position on the track 15%), the seal pusher 1-56 is adjacent the rest position of the scaling jaw assembly 30, in seal delivering relation therewith. The lever 140 also carries a projection having a lower shoulder 158 and an upper shoulder 169, which shoulders are adapted to be engaged respectively by a COCliing finger 16d and a tripping finger 166 pinned on shaft 953 for rotation with lever 96 during operation of the sealing mechanism. The end of the shaft 98 enclosed by the slot 141 in the lever 141i is provided with a longitudinal concave cutout 170 disposed opposite the inner corner 172 of the slot M1, for a purpose explained hereinafter.

The operation of seal feeding mechanism it? will now be described. As the sealing handle 12 is rotated from the front to the back of the tool and the sealing jaws S5 descend to embrace the ends of the strap, the accompanying rotation of the cams 1G6, 198 and cranks 132i, 154 about axis 116 pivots lever 9d and rotates shaft 93. This brings lower finger 164 into engagement with lower shoulder 153 on lever Mil. Since the lever 14") is sup ported for both rotation and sliding movement with respect to shaft 98, and since the lower end of lever 140 is attached to seal pusher 14-6 and thereby constrained to slide along track 150, the engagement of lower finger 164 with lower shoulder 158 and subsequent counterclockwise rotation of lower finger 164 with shaft 98 moves seal pusher 146 forward on track 150 beneath the lower most seal, to an extreme position at the forward side of magazine 8, as shown in Figure 3.

The top of seal pusher 146 is shaped to conform with the channel-shaped cross section of the seals. The sides of the lowermost seal in magazine 8 rest on flanges 152. The height of the rear edge of seal pusher 146 above the flanges 152 is suflicient that, when once displaced to position forward of magazine 8, seal pusher 146 is enabled to engage positively the top of the lowermost seal for extraction thereof from magazine 8 when seal pusher 146 is returned rearwardly along the track 150. The top of seal pusher 146 has a slight slope, being lower at its front edge, so that it is cammed smoothly beneath the lowermost seal, raising the stack of seals in the magazine momentarily as it is carried forward on track 150.

The fact that the lower end of lever 140 is constrained to move along track 150 requires that lever 140 slide downwardly with respect to shaft 98 when seal pusher 146 is moved forward. As the lower end of lever 140 reaches its point of extreme forward displacement on track 150, the action of lower finger 164 pushing up on lower shoulder 158 pivots lever 140 about its lower end and seats shaft 98 into the transverse portion 144 of the slot 141 in the lever, as shown in Figure 3. This action serves to latch the seal feeding mechanism 10 in the cocked position where seal pusher 146 is capable of extracting a seal from the magazine 8.

It should be understood that, as will be apparent from a consideration of the structure shown in Figure 5, lever 140 cannot be moved from the position shown in Figure to the position shown in Figure 3 until lever 96 has been rotated sufficiently counterclockwise, during the accompanying counterclockwise rotation of cams 106, 108 by sealing handle 12, to engage lower shoulder 158 with lower finger 164 and displace seal pusher 146 forward on track 150 underneath and beyond the lowest seal. Displacement of seal pusher 146 this far forward on track 150 can be accomplished only by rotation of sealing handle 12 through its full arc from its initial forward position, as shown in Figure 2, to its rearwardmost position. Thus the sealing mechanism 6 must be fully operated and any seal therein deformed in the usual manner by the closing of the sealing jaws 86 before seal pusher 146 is positioned far enough forward on the track to be capable of extracting a sea] from the magazine.

The forward displacement of the lower end of lever 140 along track 150 stretches the spring 154 by which it is urged rearwardly of frame 2, and hence lever 140 is strongly biased rearwardly of track 150. However, seal pusher 146 is prevented from returning rearwardly on track 150 because such motion requires an accompanying longitudinal sliding motion of latching lever 140 relative to the shaft 98 in order to shorten the distance between the lower end of lever 140 and shaft 98 as the constrained lower end of lever 140 returns along track 150. This necessary sliding motion of lever 140 relative to shaft 98 is prevented by the seating of shaft 98 in the transverse portion 144 of the L-shaped slot 141 in lever 140.

As the sealing handle 12 is returned toward its forward position at the end of the sealing operation, the accompanying rotation of cams 106, 108 permits spring 82 to raise arms 74, 76 and jaw assembly 80 away from the sealed straps, the jaws 86 simultaneously being opened by springs 88. This return motion of the sealing handle 12, however, does not immediately move lever 140 out of the position shown in Figure 3, because the seating of shaft 98 in transverse slot 144 prevents the sliding of lever 140 relative to shaft 98 which such movement necessarily entails.

As sealing handle 12 is returned further toward its forward position, the lever 96 is eventually rotated sufficiently so that,'as shown in Figure 3, upper finger 166 engages upper shoulder 160 on lever 140 and serves to pivot lever rearwardly about its lower end. At the same time the shaft 98 becomes so rotatively aligned that the cutout portion 170 receives the inner corner 172 of lever slot 141 and permits the lever 140 to be pivoted enough for relative movement of the slot corner 1'72. across this cutout portion 170. This relative movement aligns the longitudinal leg 142 of lever slot 141 with the shaft 98.

When so aligned, lever 140 can he slid upwardly relative to shaft 98, and this unlatches the seal feeding mechanism and enables spring 154 to move the lower constrained end of lever 140 abruptly rearward along track 150. This displaces seal pusher 146 rearwardly on track 150 toward the sealing jaw assembly 80. In being so displaced, seal pusher 146 engages the front end of the lowermost seal and carries it down track 150 and into the seal receiving cavity between the jaws 86 of the jaw assembly 80.

The arrangement of the elements is such that the upper finger 166 does not contact upper shoulder to begin pivoting lever 140 rearwardly about its lower end until the sealing handle 12, and with it the jaw assembly 80, has been returned substantially completely from its operative position to its rest position. Thus it may be seen that it is a particular feature of the present invention that seal feeding mechanism 10 is rendered substantially foolproof by the requirement that the sealing handle 12 be rotated through the full arcuate displacement required to complete a strap sealing operation before the seal feeding mechanism 10 is enabled to extract a fresh seal from the magazine 8. And, even after the seal feeding mechanism 10 is thus positioned in seal extracting relation with the magazine 8, no seal can be withdrawn from the magazine until the sealing handle 12 has been returned almost completely to its initial rest position. This means that idle or speculative oscillation of sealing handle 12 through anything less than a complete excursion between its initial rest position and its approximately diametrically opposite sealing position cannot accidentally feed seals into the sealing jaw assembly 80. Since the sealing mechanism 10 will automatically be cycled through a complete sealing operation in response to such an excursion of the sealing handle 12, thereby deforming and discharging any seal previously held between the sealing jaws 86, jamming of the sealing jaw assembly 80 by the feeding of extra seals therein is precluded.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim as my invention:

1. In a box strapping tool of the type having a frame, a sealing mechanism supported in said frame for movement between a rest position and a sealing position, a magazine on said frame carrying a stack of seal members, a seal feeding member supported on said frame for reciprocation between a seal delivering position in align ment with the rest position of said sealing mechanism and a seal extracting position at said magazine, and a control handle for moving said sealing mechanism between its rest and sealing positions, linkage means interconnecting said sealing mechanism and seal feeding member for displacing said feeding member into said seal extracting position responsive to movement of said sealing mechanism to said sealing position, locking means on said linkage means for securing said feeding member in said extracting position, and trip means connected to said linkage means and operative to disengage said locking means to release said feeding member for movement from its seal extracting position to its seal delivering position responsive to movement of said sealing mechanism toward its rest position.

2. In a box strapping tool of the type having a frame, a sealing mechanism mounted in said frame for movement between a rest position and a sealing position, an operating handle for movin said sealing mechanism between its rest and sealing positions, a magazine carrying a stack of seal members, a seal feeding member supported for reciprocation beneath the magazine between a seal extracting position and a seal delivering position, and means biasing the seal feeding member into seal delivering position, the combination comprising a link pivotally connected at one end to the seal feeding member, a pivot member fixed relative to the frame pivotally and slidably connected to the other end of the link, means including a pivoted lever connected to the operating handle for pivoting the link to move the seal feeding member to seal extracting position as the operating handle is moved to sealing position, latching means including a shoulder on said link for preventing sliding movement of the link when the seal feeding member is in seal extracting position, and means connected to the pivoted lever for engagement with said link to disengage said shoulder during movement of the operating handle to the at rest position.

3. In a box strapping tool of the type having a frame, a sealing mechanism supported on the frame for movement between a rest position and a sealing position and including sealing jaws for deforming a seal contained therein when the mechanism is in sealing position, an operating handle for moving said sealing mechanism between its rest and sealing positions and for actuating the jaws in sequence, a magazine carrying a stack of seal members for successive alignment with the sealing jaws when the sealing mechanism is in its rest position, a seal feeding member supported for straight-line reciprocating movement beneath the magazine between a seal extracting position and a seal delivering position. and means biasing the seal feeding member into seal delivering position, the combination comprising a rotatable member connected to the operating handle for rotation thereby, a link pivotally connected at one end to the seal feeding member and pivotally and slidably mounted at its other end on said rotatable member, means on said rotatable member for pivoting the link in one direction to move the seal feeding member to seal extracting position when the operating handle is moved to the sealing position, a stop for preventing movement of the link in the other direction when the link is in its latter position, and second means on the rotatable member to disengage the stop and permit movement of the link in said other other direction when the operating handle is moved toward the rest position.

4. In a box strapping tool of the type having a frame, a sealing mechanism supported on the frame for movement between a rest position and a sealing position and including sealing jaws for deforming a seal contained therein when the mechanism is in sealing position, an operating handle for moving said sealing mechanism between its rest and sealing positions and for actuating the jaws in sequence, a magazine carrying a stack of seal members for successive alignment with the sealing jaws when the sealing mechanism is in its rest position, a seal feeding member supported for straight-line reciprocating movement beneath the magazine between a seal extracting position and a seal delivering position, and means biasing the seal feeding member into seal delivering position, the combination comprising a link pivotally connected at one end to the seal feeding member and having a L-shaped slot in its other end, said L-shaped slot having a longitudinal portion and a transverse portion, a fixed pivot engaged in said slot for supporting said other end of the link for sliding and pivoting movement when engaged in the longitudinal portion and for pivoting movement only when engaged in the transverse position of the slot, means actuated by the handle pivoting the link to move the seal feeding member to seal extracting position and to engage the pivot in said transverse slot when the operating handle is moved to the sealing position, and second means actuated by the handle for moving the link in an opposite direction to disengage the transverse slot from the pivot when, the operating handle is moved toward the rest position.

5. In a box strapping tool of the type having a frame, a sealing mechanism supported on the frame for movement between a rest position and a sealing position and inc uding sealing jaws for deforming a seal contained therein when the mechanism is in sealing position, an operating handle for moving said sealing mechanism between its rest and sealing positions and for actuating the jaws in sequence, a magazine carrying a stack of seal members for successive alignment with the sealing jaws when the sealing mechanism is in its rest position, a seal feeding member supported for straight-line reciprocating movement beneath the magazine between a seal extracting position and a seal delivering position, and means biasing the seal feeding member into seal delivering position, the combination comprising a rotatable shaft connected to the operating handle, a link pivotally connected at one end to the seal feeding member and having an L-shaped slot in its other end embracing said shaft, said L-shaped slot having a longitudinal portion and a transverse portion, means mounted on said shaft for pivoting the link to move the seal feeding member to seal extracting position and to engage the shaft in said transverse slot when the operating handle is moved to the sealing position, and second means on the shaft for moving the link in an opposite dircction to disengage the transverse slot from the shaft when the operating handle is moved toward the rest position.

6. in a box strapping tool of the type having a frame, a sealing mechanism supported on the frame for move ment between a rest position and a sealing position and including sealing jaws for deforming a sea], contained therein when the mechanism is in sealing position, an operating handle for moving said sealing mechanism between. its rest and sealing positions and for actuating the jaws in sequence, a magazine carrying a stack of seal members for successive alignment with the sealing jaws when the sealing mechanism is in its rest position, a seal feeding member supported for straight-line reciprocating movement beneath the magazine between a seal extracting position and a seal delivering position, and means biasing the seal feeding member into seal delivering position, the combination comprising a rotatable shaft connected to the operating handle, a link pivotally connected at one end to the seal feeding member and having an L-shaped slot in its other end embracing said shaft, said !.-shaped slot having a longitudinal portion and a transverse portion, a cooking finger fixed to said shaft and engageable with one side of the link for pivoting the link in a direction to move the seal feeding member to seal extracting position and to engage the shaft in said transverse slot when the operating handle is moved to the sealing position, and a tripping finger fixed to the shaft engageable with the other side of the link for moving the link in an opposite direction to disengage the transverse slot from the shaft when the operating handle is moved in the opposite direction toward the rest position.

References Cited in the file of this patent UNITED STATES PATENTS

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