US2072826A - Article transferring mechanism - Google Patents

Description

2 Sheets-Sheet l C. S. RILEY Filed June 5, 1935 In 0 en tor: a/zedfzfiifqy A Horn eggs.

ARTICLE TRANSFERRING MECHANISM Wi tn ess:

March 2, 1937. Q 5, RlLEY 2,072,826

ARTICLE TRANSFERRING MECHANISI Filed June 5, 1935 2 Shoots-Shoot 2 In ven tor: v gfla/ze anfiieqy b yflmv M A ttorne ys.

Witness:

Patented Ms. 2, 1937 UNITED STATES ARTICLE TBANSFERRING MECHANISM Clare s. Riley, Windsor, Com, assignor to Hart-- ford-Empire Company, Hartford, Conn., a corporation of Delaware Application June 5, 1935, Serial No. 25,015

Claims,

'l'hisiinvention relates to article mechanism and more particularly to a tongs mechanism usable in stacking articles, such as bottles, in close. relation to each other. 5 In the use of stacking devices of the type which pick up an article, such as a bottle, from a conveyor or buck at a predetermined point and set it down at a delivery station, which .may be on the conveyor belt of a glasswareannealing difilculty above set forth, specifically by providing a means for .limiting the opening movement of tongs in releasing an article at the delivery sta-v tion or position, while permitting the full opening of the tongs at some subsequent time, preferably after the tongs and their carrier or support have been moved bodily away from the delivery position, so that the full opening of the tongs will not cause them to hit adjacent 'articles. It is desired that tongs used in stacking glassware, *and for certain other purposes, be fully opened prior to their being brought to the receiving station in order that they-may grasp articles which may not be accurately spotted at that station.

A further and relatively specific object of my present invention is to provide for the adjustment of the degree of the initial or partial opening of the tongs in a, manner-independent of the fully opened or fully closed positions, so as to compensate for the different spacing between articles usable, for example, when the device is used on a lehrstacker.

A further specific object'of the invention is to provide adjustable timing means for controlling as desired the interval between the initial or partial opening of the tongs and the subsequent or full opening thereof.

50 Other and more specific objects of the present -invention will appear from the following description of a preferred embodiment thereof and in the appended claims, all when, taken in conjunction with the accom 5.5 which:

drawings in transferring Figure 1 is a view principally in elevation of stacker tongs with my improved device associated therewith, certain of the operating means for the tongs opening retarding mechanism being shown in vertical section; Fig. 2' is a view of the device principally in cen-' tral vertical section taken at right angles to the view of Figure 1;

.Fig. 3, is a view partly in plan and partly in horizontal section of the device, the sectional view being on the line 3-3 of Figs; 1 and 2;

Fig. 4 is a view substantially in orizontal section on the line 4-4 of Fig. 2;

Fig. 5 is a fragmentary view similar to Fig. 1 but at a difl'erent angle and showing certain of the passage means between the main tongs operating mechanism and the auxiliary cylinder, the parts in section being shown on the line 5-5 of Fig; 3; Y

4 Fig. 6 is a fragmentary view in elevation showing an'application of mechanism embodying my invention; and

Fig. '7 is a fragmentary view in horizontal section taken on the line 'I--'| of Fig. 5. v I

I have chosen to illustrate my invention as applied to the stacking tongs of the Hartford- Empire stacker, which is shown in Lorenz Patam No. 1,878,156, granted September 20, 1932. Fig. 6 of the present drawingsvcorresponds generally to the lower portion of Fig.3 of the Lorenz patent. It will be understood, however, that my invention may be applied not only in other types of stackers,- but also in devices-usable for somewhatdiiferent purposes, and in fact wherever the results attainable by the use of the invention are applicable.

' In its normal operation, the Hartford-Empire stacker is arranged to pick up bottles or other glass articles at a single position on a buck or conveyor and place these bottles in different positions on the conveyor belt of a glass annealing lehr. The result of stacking as attained by the Hartford stacker is that the entire or a predetermined part of the area of the lehr conveyor is filled with the articles which are being stacked in substantially uniformly spaced relation, the articles being preferably close together, but not touching.

It will be understood therefore, that while the present claims refer to a receiving position, which is in the usual case a single position at whichthe articles are spotted on the conveyor or buck to be picked up, and also refer to a "delivery position", this last position may be and in fact is a plurality of different positions on the conveyor belt of the lehr in the case of the Hartford-Empire stacker. This variation in'the actual point at which bottles are delivered by the stacker is accomplished by a lateral indexing 6 movement of the stacker mechanism about a center which is in vertical alignment with the receiving position for the bottles. However, inasmuch as this feature is not a part of my present invention, but is disclosed and claimed in the Lorenz patent above referred to, it is not thought necessary to go into detail except to bring out that the delivery position" expressed in theappended claims'may not be one single position, but is to be construed as including any and all points at which bottles or other articles being transferred'are delivered by the stacking or transferring means provided.

Referring first to Fig. 6, which as above stated cor-responds generally to a part of Fig. 3 of the Lorenz patent above referred to, there is illustrated a depending bracket I, which is supported from above in a manner specifically described in the Lorenz patent. To the lower end of the bracket there is pivoted at 2 a swinging arm 3 on which the stacker tongs hereinafter to be de scribed are suitably mounted. For swinging the arm 3 about the axis 2, there is provided a sprocket chain 4 engaging with a sprocket wheel 5 which is secured to the arm 3. One end of the sprocket chain 4 is connected to a resilient device 6 while the other end is connected to a suitable prank both shown and described in detail in the Lorenz patent, but not illustrated in the accompanying drawings. Suflicient be it to say for the present purposes that movement is imparted to the sprocket wheel 5 and 'the arm 3 through the sprocket chain 4 from suitable operating mechanism to move the arm between the full and dotted line positions shown in Fig. 6. A spring I is I: connected between a suitable anchorage and a bracket 8 rigid with the arm 3 to serve as a counterbalance and for certain other purposes, all of which are fully described in the Lorenz patent. The outer end of the arm 3 supports a suitable pintle on which is secured a split bracket 9 which clamps" around the barrel portion III of the tongs support which is generally indicated at H. In order that the tongs may be retained vertical to sustain an article in vertical position during the movement thereof from the buck B to the lehr conveyor L shown in Fig. 6, there is provided a parallel motion device'comprising a sprocket wheel |2 which. is secured to-a sleeve 66 rigid with the bracket and also a sprocket l3 having the same number of teeth and pitch as the sprocket l2 and which is secured to the pintle carrying the split bracket 9. Surrounding the sprocket wheels 12 and I3 is a sprocket chain I4',

the ends of which may be connected by a spiral ,tension spring l5 as shown. The sprocket |2 being secured to the bracket I doesnot rotate and hence rotation ofthe arm 3 around the axis 2 will cause the chain I4 to move about the sprockets l2 and i3 without any variation of the sprocket |3 from its initial angular position in respect to the vertical, thus retaining the barrel portion ill of the tongs Support I| always vertical.

In. this way articles such as the bottle A are picked up at the receiving position shown at the right in Fig.- 6 and moved to the position at which the bottle C is located on the belt L, the tongs being shown .at this position just releasing the article and being partly opened so as not to engage and topple over the bottle D adjacent to the bottle C. The means for opening the tongs only partially in releasing a bottle form the principle subject matter of the present invention as hereinafter to be describe The barrel portion ill of the tongs support I! is clamped in a desired vertically adjusted position by suitable bolts IS in the-split bracket 8. At the lower end of the support N there is secured a fluid pressure cylinder IT. This cylinder is formed with a reduced portion l8 (Fig. 2), which is secured within the lower end of the barrel I0 and which is formed with an axial bore l9 extending vertically 'therethrough. A piston 28 is mounted for vertical reciprocation within the cylinder l1 and is provided with a piston rod 2| which extendsthrough the bore |8 and upwardly through the barrel Ill. The piston 20 is urged upwardly by a coil spring 22 which encircles the rod 2| and which isinterposed between a sleeve 23 loosely surrounding the lower end of the rod 2| adjacent to the reduced portion l8 of the cylinder l1 and an adjustable nut (not shown) which is threaded onto the upper end of the rod 2|. This nut may be so positioned as to engage beneath an adjustable stop screw 24 (Fig.- 6) for limiting the closing movement of the tongs by limiting the upward movement of the piston 20 in cylinder l1.

The lower edge of the cylinder I1 is provided with diametrically opposed ears 25 (Fig. 1), between each pair of which a tongs holder 26 is pivotally mounted by means of a pivot pin 21. gripping fingers 28, one of which is detachably secured to each of the holders 26 and eachof which is formed with an inwardly projecting portion 29 provided with a suitable notch or groove for engaging beneath the neck finish 38 of a bottle, as shown in Fig. 2. The tongs holders 26 are also each provided with an inwardly projecting arm 3| which are oflset relative to each other (Fig. 4) and which are each pivotally connected to the lower end of one of a pair of links 32 (Figs. 2 and 4). The upper ends of the links 32 are pivotally connected to the piston 28 by means of a wrist pin 33 and aremaintained in spaced relation to each other by means of a spacingwasher 34. By means of this construction, when air pressure is admitted to-the cylin-' der l1, the piston 28 will be depressed, thus caus ing the gripping fingers 28 of the tongs to open. whereas when air pressure within the cylinder is relieved, the spring 22 will elevate the piston 28 and close the tongs about the ware. It will be pairs or depending .The tongs comprise a pair of apparent that the ware is yieldingly engaged by toQsecure the tongs 28 to. the holders 26,'but also are elongatedand extend inward so that they may be adjusted to abut each other at the closed position of the tongs. in the vtongs members 26 so that they may be adjusted in and out to 'predetermine the closed position of the tongs as aforesaid and-are pro- These screws are threaded vided with nuts 36 forclamping thetongs mem-' bers 28 to their holders 26. Either or both of the above-named adjustments maybe employed .to predetermine the closed position of the tongs.

Pressure may be conducted from a suitable I valve means under control of a-timer (not shown) to the cylinder II, this pressure being transmitted to the cylinder in the same way as is specifically disclosed in the Lorenz patent above referred to. Briefly, pressure is conducted, in a manner not particularly illustrated here, down the bracket I (Fig. 6) and thence through suitable transmitting means, some or which are pref erably concentric with the axis 2 or the arm 3, thence through a hollow portion of the arm 3 and suitable pressure transmitting passages in the pintle on which the split bracket 9 is mounted to a chamber inside the bracket, whence the pres- 1 sure may pass through a hole 31 (Fig. 2) in the barrel portion ill of the tongs supportto the interior of this barrel portion. Pressure may then pass between the piston rod 2| and the loose sleeve 23 and through a groove 38 cut in'the piston rod past the bore I901 the reduced portion l8 of the cylinder l1 and into the upper end of the cylinder. Suitable meansmay be provided as disclosed specifically in the Lorenz, patent above referred to for controlling the application and exhaust or pressure at the desired times. The construction thus far described is substantially identical with that disclosed in the Lorenz patent, and while it has been briefly treated herein, reference may be had to the Lorenz patent for- 30 a specific description of the various mechanisms I of the stacker.

I have shown at 39 (Fig. 2), a plug inthe upper portion of the cylinder ll which may be utilized in practice for plugging a hole at-which point a pressure gage may be screwed in it desired, This is merely an operating device con-'- venient in testing the apparatus and is shown herein, as the present drawings were made from the working drawings, of the commercial device.

I have also illustrated in Fig. 2 a vent passage 45 controlled by an adjustable bleed valve 4|v which may be used in practice to insure the rapid exhaustion of pressure from within the cylinder I1, so as to permit the rapid closing of the tongs. 45The valve 4| is. adjusted, however, so that when pressure is supplied to the cylinder l1, for opening the tongs, this pressure will not leak out 'fast enough to preventthe rapid opening of the tongs. Means are provided according to my invention 50 for limiting the initial opening movement of the V tong s in'depositing an article to a point just sumcient for releasing the article, while preventing the full opening thereof for a predetermined and preferably adjustable time during which the tongs may be moved bodily away from the delivery position and such that the full opening thereof will not cause them to hit an adjacent article.

For this purpose, there is provided a second pneumatic cylinder '42 adjacent to the cylinder I1 andpreferablysecuredto the tongs support I l by being provided with a split clamping member 43' which may be integral therewith and which is secured to the barrel III by means of a arranged for ,movement with one or the tongs clamping bolt 44. The cylinder 42 is provided X members 25, the left hand'one as seen in Fig. 2.

The dog 48 is loosely mounted on one of the pintles 21, as best shown in Figs. 1, 2 and 4, and isprovided with a tail portion 49 having threaded therethrough an adjustable bolt 50, the inner end or which is adapted to engage against an extension 5l of the tongs holder 25 adjacent thereto. A light spring 52 isprovided which continuously urges the end of the screw 55 against the extension 5| and thus tends to retain the dog 45 in a predetermined relative position in respect to the associated tong 28.

As best shown in Fig. 2, when the tongs are moved from their closed position shown in full lines toward their open position, the dog 45 will be moved in a clockwise direction about the axis of the pintle 21 on which it is mounted, due to the engagement of the inner end of the screw 50 with the extension 5i. It at this time the piston rod 41 is in its lowermost position to which it is urged by the spring 45, then the tongs can open a predetermined amount only, specifically to the dotted line position shown in Fig. 2, as at that position the upper end of the dog 48 will engage against the iower end of the piston rod 41. The tongs cannot open further until the piston 45 has been raised in cylinder 42, whichis acconrplished ina manner hereinafter to be described, at which time the tongs may be fully opened under the continued action of pressure in cylinder l1.

It will be seen also that the intermediate position of the tongs may be manually adjusted as desired by adjusting the position of the screw 55 in respect to the tall 49 of the dog 45, this adjustment being secured by a jam nut 53.

g For moving the piston 45 upwardly'in the cyl- These passages include desired adjusted position and the adjustment secured by a jam nut 58. Thus when pressure is supplied to the cylinder H for opening the tongs, the same pressure passes through the passageways 54, 55 and 55 tn the lower end of cylinder 42' tending to move the piston 45 upwardly against the spring 46 and permit the full opening thereof. However, this pressure to cylinder 42 may only pass into the cylinder slowly under the control of the needlevalve 51.

There. is further provided in cylinder 42 an enlarged chamber as shown at 59, beneath the piston 45, so that pressure will be some predetermined time in building up sufliciently in tho cylinder 42 before the piston 45 is moved up.- wardly against the spring 46. This in practice affords sufllcient time for thetongs to be moved The time of release of the dog 48 from the piston rod 41 is preferably manually adjustable. by adjusting the needle valve 51, so that the apparatus maybe suitably adjusted for different rates of operation.

As above stated, I contemplate that my invenany use for which it is applicable or desirable. I further contemplate that any desired means, pneumatic or otherwise, may be employed for retarding the full opening of the tongs for apredetermined and preferably tion may be applied to adjustable time after the tongs have been opened partially to release an article for the purpose above set forth or for any other desired purpose. I contemplate that various changes may be made in the construction and relationship of parts, and equivalent mechanism may be substituted wherever it may to be limited, therefore, except by the scope of the appended claims, which are to be construed as broadly as the state of the priorart permits. I claim:

1. .Article transferring mechanism, comprising a-support, tongs on said support arranged to be opened and closed and to grasp articles to be be desirable. I'do not wish.

- der will thereafter operate to permit the full openthe articles after movement of said support at a delivery position, means operative at the receiving'positionfor moving said tongs from their fully opened to their fully closed position in grasping an article to be transferred, and means op- .erative when the tongs have moved an article to the delivery position for moving the tongs from theirfully closed position a predetermined distance onlytoward their fully open position to release an'article and after'the tongs have been bodily moved by movement of said support away from the delivery position to move the tongs in respect to said support the remainder of the way to their fully open position.

3. Article transferring mechanism, comprising a support, tongs on said support arranged to be delivery position,

opened and closed'and to grasp articles to be transferred at a receiving position and deposit the articles after movement of said support at a pneumatic means for operating saidtongs at least as to the opening thereof, and means for automatically controlling the operation of said pneumatic means in opening said tongs and so constructed and arranged that the tongs can be opened a predetermined part'ofthe way leasing an'article at the delivery position and thereafter to move in such manner and direction as to permit the full opening of the tongs by the first named pneumatic means.

5. Article transferring mechanism, comprising a support, tongs on said support arranged to be opened and closed and to grasp articles to be transferred at a receiving position and deposit the articles-after movement of said support at a delivery position, pneumatic means for operating said tongs at least as to the opening thereof, and a pneumatically operated delay action device cooperating withthe tongs' opening means for limiting the opening movement of the tongs to a predetermined extent in releasing an article held therein and'thereafter'moving to a position permitting the first-named pneumatic means to open the tongs fully, both said pneumatic means being operated byv a single application'of pneumatic pressure. i

6. Article transferring mechanism, comprising a support, tongs on said support arranged to open and close and to grasp articles to be transferred at a receiving position and deposit the articles after movement of said support at a delivery position, pneumatic means for operating said tongs at least to the opening-thereof, and a pneumatic cylinder cooperating with the tongs to' delay the full opening thereof for a predetermined time after pressure has been supplied to the first named pneumatic means tending to open the tongs,'the parts being so constructed and arranged that the initialapplication of pressure to the pneumatic means will open the tongs to a predetermined extent only but' suflicient torelease an article held thereby, and said pneumatic cylining of the tongs.

7. Article transferring mechanism, comprising a support, tongs on said support arranged tobe' opened and closed and to grasp articles to be transferredat a receiving position and deposit the articles after movement of said support at a delivery position, pneumatic means for operating said tongs at least as to the opening thereof,

opening-thereof.

' ferred at a receiving position and deposit the v said tongs at least i only in releasing an article at the delivery posi-t tion and thereafter the tongs will be openedto their fullest extent. 4. Article transferring mechanism, comprising a support, tongs on said support arranged tobe,

opened and closed and to grasp articles to be transferred at a receivingposition and' deposit the articles after movement of said support at a delivery position, pneumatic means for opening said tongs, andother pneumatically operated means for automatically limiting the opening of said tongs at an intermediate position thereof in re-- 8. Article transferring mechanism, comprising a support, tongs on said support arranged to open'and close and to grasp, articles to be transarticles after movement of said support at a delivery position, pneumatic means for operating as to the opening thereof and actuated by the supplying of pneumatic pressure thereto to open the tongs, a pneumatic cylinder having a piston therein cooperating with said tongs for delaying the full-opening thereof for a predetermined time after'press'ure has been sup- 7 plied to the first-named pneumatic means to open the tongs,

and a' bleed valve interposed between the first-named pneumatic means and said pneumatic cylinder gradually to admit pressure from the first-nanred pneumatic means'to' said pneumatic cy 'nder for moving the piston thereof in respect to the cylinder after pressure has built up in'saidpneumatic cylinder and thereby to vrmit the full pe opening of the tongs at a predeteraovasae mined time subsequent to the partial opening thereof in response to the initial application of pressure to said pneumatic means, whereby the partial opening of the tongs may be utilized to 5 release an article supported thereby and the full opening of the tongs may-,be delayed by the aforesaid means until the tongs have been bodily moved by movement of said support away from the delivery position so that full'opening of the tongs will 10 not cause them to impinge articles adjacent to the one being deposited. I

9. Article transferring means, comprising a support, tongs on said support arranged to be opened and closed and to grasp articles to be 15 transferred at a receiving position and deposit the articles after movement of said support at a delivery position, an-air cylinder connected with said tongs, spring means associated with said air cylinder and tending at all times to close said tongs, thev 2.0 air cylinder being so constructed and arranged that when pressure is suppliedthereto, the tongs will be opened in opposition to said spring means, a second air cylinder having a piston therein associated with said tongs and arranged in one posi- 25 tion of the piston thereof to prevent the full opening of. said tongs while permitting the partial opening thereof, spring means in said second cylinder tending to move the piston thereof to a position to prevent the full opening of said tongs, a bleed passage between said two cylinders, and a manually adiustable bleed valve in said bleed passage, the parts being so constructed and arranged that in depositing an article at the delivery position of the tongs, pressure is supplied to 5 the first named cylinder tending to open the tongs,

this opening movement being limited by the relative position of the second air cylinder and the piston thereof to an intermediate position at which an article is released from the tongs and 40 the piston and second cylinder will thereafter be relatively moved by pressure from the first air cylinder through. said bleed valve to permit the subsequent full opening of the tongs under the continued action of the pressufi in the first-' 45 named cylinder,

10. Article transferring mechanism, comprising a support, tongs movably mounted on said support, actuating means for opening and closing said tongs, a dog movably mounted on said support arranged to be moved in a predetermined path by movement of the saidtongs, an interrupting device movable into and out of a position in the path of movement of said dog and adapted to interrupt the opening movement of said tongs at an intermediate position thereof when said interrupting device is in one position and after movement of said interrupting device to another position, to permit the full opening of said tongs, and means for moving said 'interv 60 rupting device into and out ofits position in the path of movement of said dog.

11. Article transferring mechanism, comprising a support, tongs movably mounted-on said support and arranged to graspan article and hold it in a position such that the longitudinal axis of the article will be aligned with the longitudinal axis of said support, a pneumatic cyl- \inder in said support for'opening and closing said tongs, a dog movable with one of said tongs,

' a longitudinally movable rod mounted on sad support for movement into and out of position in alignment with the path of movement of said dog, and means for moving said rod, the parts being 'so constructed and arranged that when :75 said rod is in its position in the path of movement of said dog and pressure is supplied to said pneumatic cylinder for opening said tongs; the tongs may be opened a predetermined part of the way only from their fully closed toward their fully opened position but suflicient to release an article previously held therein, and upon movement of said rod, said tongs may, be moved to their fully opened position by,said pneumatic cylinder.

12. Article transferring mechanism, comprising a support, tongs on said support arranged to be opened and closed and to grasp articles to be transferred at a receiving position and deposit I the artic les after movement of said support at a delivery position, means for closing said tongs to grasp an article at the'receiving position, means for imparting to said tongs a predetermined part only, of theirlopening movement to release an article at thefdelivery position and thereafter for completing'the opening movement of said tongs, and means for adjustably varying the amount of opening movement imparted to said tongs to release an article at the delivery position independently of the time of the partial or full opening of the tongs and of the fully opened or fully closed positions of the tongs.

13. Article transferring mechanism, comprising a support. tongs on said support arranged to be opened and closed and to grasp articles to be transferred at a receiving position and deposit the articles after movement of said support at a delivery position, pneumatic means for operating said tongs at least as to the opening thereof,

means for automatically controlling the operation of said pneumatic means in opening said tongs and so constructed and arranged that the tongs can be opened a predetermined part of the way only in releasing an article at the delivery position, and thereafter the tongs will be opened to their fullest extent, and means for manually adjusting the intermediate position to which the tongs are opened in releasing an article independent of the fully open or fully closed positions of said tongs.

14. Article transferring mechanism, comprising a support, tongs pivotally mounted on said support on parallel axes, a pneumatic cylinder in said support arranged to open and close said tongs, the opening movement of said tongs being in response to the supplying of pressure to one end of said cylinder, a dog mountedfor movement with one of said tongs and. movable therewith through a predetermined path, a second pneumatic cylinder mounted on said support, the piston rod of which is located in one position of the piston in said second cylinder in the path of movement of said dog, .a bleed passage between said cylinders, and means for resiliently urging'the piston in said second cylinder to a position at which said piston rod is in the path 'of said dog, the aforesaid parts being so consaid tongs will move the tongs to an interme-' diate position at which said dog will engage the piston rod of the second named cylinder, and subsequently pressure from the first named cylinder passing through said bleed passage will move the piston in said second named cylinder to move its piston rod out of the path of said dog and thus permit the full opening of said tongs. v

15. Transferring mechanism, comprising a support which is normally maintained vertical during article transfer, a pair of tongs members mounted on parallel horizontal axes on said support, a pneumatic cylinder in said support-connected to operate said tongs members, spring means for moving the piston in said cylinder to close said tongs, means for adjustably limiting the closing movement of said tongs. a dog mounted axially with one of said tongs but movable in respect thereto, means for adjustably controlling the angular position of said dog with respect to its associated tong, means for resiliently holding said dog i'n-a'predetermined position in respect to its associated tong, said-posimovement of said dog,

tion being subject to the angular adjustment therebetween, a second pneumatic cylinder associated with said support having a piston and pis ton rod andso located that the piston rodthere of will be in alignment with the path of movement of said dog when the piston is at one position, spring means for moving the piston in said second cylinder to the position such that the associated piston rod will be in the path of able needle valve controlling passage of pressure between the first and secondnamed pneumatic cylinders, the aforesaid parts being so constructed and arranged that said tongs may be moved at the receiving position for articles from their fully opened to their fully closed positions by the exhausting of pressure from the first named pneumatic cylinder and under the action of the are at their delivery position and it is desired to and a manually adjust after causing v-m'eans thereof. associated spring means, and when said tongs 1 release an article,

intermediate position at which the article will be released while further opening movement of c said tongs at this time is prevented due to said dog engaging the piston rodiofthe second named pneumatic cylinder, thereby preventing upsetting of the-adjacent sition, and subsequently pressure passing from the first to the second named pneumatic cylinders through said needle valve will move said articles at the delivery poopen said tongs at the delivery position for releasing articles transferred by the tongs, means 'eflective at the receiving position fortemporarily mechanically limiting the. opening of the tongs by the aforesaid means, and means for there-- movement of. position to permit the ongs by the opening CLARE S. RILEY.

means to an inoperative complete opening of th pressure may be supplied to the first named pneumatic cylinder which will move said tongs from their fully closed to an' movement of said support at .the receiving position to grasp articles and to the last-named

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