US3508780A - Control device for tongs - Google Patents

Description

April 8, 1970 D. A. BARTMAN 3,508,780

CONTROL DEVICE FOR TONGS Filed June 17, 1968 2 Sheets-Sheet l Fig.4

I I.K -2 a w 5 5 20a /5[ 0 05 mg.

INVENTOR.

DANIEL A. BARTMAN H/S A T TORNEVS April 28, 1970 pl, BARTMAN 3,508,780

CONTROL DEVICE FOR TONGS Filed June 17, 1968 2 Sheets-Sheet 2 INVENTOR.

DANIEL A. BARTMAN BY H/S ATTORNEYS United States Patent 3,508,780 CONTROL DEVICE FOR TONGS Daniel A. Bartman, Pittsburgh, Pa., assignor, by mesne assignments, to American Forge and Manufacturing Company, Inc., a corporation of Delaware Filed June 17, 1968, Ser. No. 737,404 Int. Cl. B25b 13/00 US. Cl. 294-110 7 Claims ABSTRACT OF THE DISCLOSURE A tong-operating, control or latching device is operatively-connected centrally at a pivot joint between an upper pair of lever or toggle arms and, through the agency of a latching lug and a keeper, at a pivot joint between a lower pair of lever or toggle arms that serve as a pair of tong, grapple or grip arms of a lazy-tong lifting assembly. The device has a main body surmounted by a hollow housing, with a plunger slidably-positioned within the body to extend at its upper end into the housing. The upper end of the plunger has a cam provided with opposed upper and lower camming faces. The housing carries an upper cross-extending latch pin and a pair of lower, oppositely-extending guide and latch pins. The upper and lower cam faces are shaped and sloped and have a 45 offset with respect to each other such that when the plunger moves upwardly, the upper edge of the cam will cause it to turn clockwise 45 on the upper pin and into latching engagement therewith, and when the plunger moves downwardly, the lower edge of its cam will turn it another 45 clockwise on and into latching engagement with the lower pair of pins. Up and down or reciprocating movement of the plunger and its incident rotation, as effected by the camming surfaces, is employed to move the latching lug that is carried on the lower end of the plunger into and out of a locked position within the keeper.

The invention relates to an improved device for controlling the latching and unlatching of a tong-like lifting device that is particularly suitable for use in steel mills for positively gripping and carrying a heavy object, such as a metal ingot. An important phase of the invention relates to a device whose wear parts, and particularly its cam surfaces, may be inexpensively and relatively easily replaced for maintenance purposes.

There have been prior devices used for controlling the use or operation of lifting tongs, but they have been relatively expensive to produce and have required a complete replacement of the device due to wear upon camming, pin or plunger surfaces. There has been a need in the art for a simplified form of construction which will be relatively inexpensive to produce and whose wear surface portions may be readily and inexpensively replaced in such a manner as to make continued usage of body, housing or other portions of the device that are subjected to less wear and tear.

It has thus been an object of the invention to develop an efiicient control or latching device for lift tongs, such as used with an overhead hoist or a crane for moving heavy objects, e.g., metal ingots, from one place to another.

Another object of the invention has been to find a solution to the above discussed problem of replacement of parts or portions of a control device which are subjected to the greatest wear and tear.

A further object of the invention has been to provide a new and improved form of control or locking device for lifting or grappling tongs which will employ an improved type of camming construction.

These and other objects of the invention will appear to those skilled in the art from the illustrated embodiment and the claims.

In the drawings, FIGURE 1 is -a side view in elevation of a control or latching device of the invention; in this view, its plunger is in a down position at which an underface of its cam is in latching engagement with a pair of opposed, lower-positioned latch pins. This represents a normal position of the device for retaining tong or grip arms of a lazy tong lifting assembly in an open, ready position, such as shown in FIGURE 6.

FIGURE 2 is an end section in elevation on the scale of and taken along the line 22 of FIGURE 1.

FIGURE 3 is a fragmental side view in elevation and partial section on the scale of FIGURES 1 and 2 and showing an upper face of the cam in latching engagement with an upper cross-extending latch pin; this represents the maximum upper position of the plunger, as accomplished as shown in FIGURE 8, by moving the associated tong assembly downwardly until its central portion strikes the object to be gripped and lifted; in this position, the cam has turned 45 clockwise from its position in FIGURES l and 2.

FIGURE 4 is a fragmental horizontal section on the scale of and taken along the line 44 of FIGURE 3, but showing a pair of removable side wall enclosing pieces that may be employed to completely close-off the hollow central portion of a cam receiving housing.

FIGURE 5 is a horizontal section on the scale of and taken along the line 55 of FIGURE 1; the full lines of this figure illustrate a right-angular, starting, down position of the plunger and the dot and dash lines represent up and down 45 turned positions when the plunger has reciprocated to turn it from the position of FIGURES 1 and 2 to the position of FIGURE 3.

FIGURE 6 is a reduced side view in elevation and partial section illustrating a mounted positioning of the device shown in FIGURES l, 2 and 3, as employed with a lazy tong lifting assembly. In this view, the cam of the plunger of the control device is in a latched, down position, wherein it retains a pair of tong or grip arms of the assembly in an open relationship to bypass an end portion of an item, such as an ingot, when the assembly is to be moved downwardly with respect thereto, see FIG- URE 8.

FIGURE 7 is a horizontal sectional detail on the scale of and taken along the line 77 of FIGURE 6.

FIGURE 8 is a side view in elevation on a reduced scale with respect to FIGURE 6, illustrating a maximum down position of the assembly at which a central portion of it strikes the object, such as an ingot, that is to be gripped and lifted, so as to move the plunger of the control device to its maximum upward position, represented by FIG- URE 3.

FIGURE 9 is a 'view on the scale of and similar to FIGURE 8, but showing the assembly in a gripping or clamping position for lifting and handling an object, such as an ingot; in this position, the plunger of the control device is unlatched from the keeper part thereof.

Referring particularly to FIGURES 1, 2 and 3 of the drawings, a control or latching device 10 is shown having a somewhat heavy or weighted main body part 11 of an oblong or offset shape to provide for mounting it on or connecting it to a pair of upper lever or toggle arms 31 and 32 of lazy-tong lifting assembly 30, see FIGURE 6 of the drawings. One hole portion 11b is adapted to receive a mounting-pivot pin 37 for arms 31 and 32, and a second hole portion is adapted to receive a pin 39 to rigidly secure the body 11 to the arm 31. A central vertical bore portion 11a extends through the main body 11 to slidably-receive a central, cylindrical, slide body portion 15a of an operating plunger 15. The plunger 15 is adapted to reciprocate within the bore 11a and has'a lower end portion 15b in the form of a reduced diameter neck on which connecting or latching lug 16 is securelymounted or integrally formed. As shown in FIGURES 1 and 2, the latching lug 16 is of somewhat rectangular shape, is elongated in one direction and has a slight downward convergence along its opposed elongated or wide sides to fit within an elongated latching slot portion 29, as defined by a pair of spaced-apart claws or fingers 28 of a keeper 27. The keeper 27 is shown formed as an upwardlycentrally-positioned integral portion of tong, grapple or grip arm 33.

The plunger has a cylindrical upper end portion 150, also of reduced diameter, which is adapted to be guidablyslidably moved between a lower pair of endwise-opposed and spaced-apart latching pins and 20. As shown particularly in FIGURE 4, the pins 20 and 20' extend from opposite closed sides of an upper extension housing 12 and have concave inner ends in a spaced relation that substantially corresponds to the diameter of the upper end portion 150 to thus guide such portion in up and down movement. A cam element or part 17 is secured on or integrally-formed with the upper end portion 150 for slidable up and down or reciprocating movement within a vertically-elongated open central or spacing portion of the extension housing 12. The cam 17, as shown in FIG- URES 1 and 2, has a cylindrical outer diameter substantially corresponding to the inner diameter of the central or spacing portion defined between opposed closed sides of the extension housing 12 for guided-sliding movement therealong. In addition, the cam 17 has an outward extension thickness with respect to the outer diameter of the upper end portion 150 that substantially corresponds to the inner extension of each of the lower pins 20 and 20' within the extension housing 12. Although the housing 12 is shown open on two opposed sides in FIGURES l to 3 for simplicity of illustration of the operation of the cam 17, it will preferably be closed-01f (see FIGURE 4), as by a pair of side walls that may be removablysecured to the opposed closed side wall of the hou ing by bolts or screws 41.

The cam 17 has an upper edge or face 18 that is contoured with ridges and valleys to latch-engage on an upper cross or through-extending latch pin 23, and to turn the plunger 15 clockwise when it is raised to the position of FIGURES 3 and 8. Upwardly turning movement of the plunger 15 is accomplished when a central portion of a pair of combined lever or toggle and tong, grapple or grip arms 33 and 34 engages and their central, connecting pivot pin 36 is moved upwardly by an object, such as an ingot 45 as shown in FIGURE 8. A lower face or edge 19 of the cam 17 is contoured with ridges and valleys to engage the lower pair of pinS 20 and 20 and turn the plunger 15 clockwise an additional 45 when the plunger is moved vertically-downwardly and to, at the same time, latch-engage the pair of pins at such downward position to hold the pair of tong, grapple or grip arms 33 and 34 of toggle tong assembly 30 in an open or spread-apart relation, such as illustrated in FIG- URE 6 of the drawings.

As shown in FIGURES 1 to 4, the lower pair of latch pins 20 and 20' are secured in an endwise-removably aligned relation within the housing 12 by a pair of crossextending tongue pieces 21 and 21' that fit within slot or cross groove portions 20b and 20b of the pins. Set screws 22 removably-secure the pieces on the extension housing 12. The upper, fully cross-extending latch pin 23 is also endwise-removable from the housing 12. Cross-extending tongue piece 24 is adapted to fit within slot or cross groove portion 23b and to be secured on the housing 12 by set screws 25.

The locking lug 16 of the plunger 15 will be in either a full right-angular or perpendicular position with respect to the main body 11 or a full parallel position with respect thereto when the plunger is in its down position and its lower camming edge or face 19 is in engagement with the opposed lower set of pins 20 and 20. Assuming that the lug 16 has a locked starting position A,

4 illustrated by the full lines of FIGURE 5 (having been previously inserted downwardly between fingers or claws 28 and turned within latching slot portion 29 of the keeper 27 to a position at right angles to claws or fingers 28), it will be turned by 45 to dot and dash line position B when the plunger 15 is moved to its upper position of FIGURE 3, and then will be turned to a second dot and dash line position C when the plunger is permitted to again lower to the position of FIGURES 1 and 2. Thus, in FIG- URE 5, position A represents a fully locked position of the latching lug 16 within the latching slot portion 29 of the keeper 27 (see also FIGURE 7), B represents a partially unlocked but retained position within the keeper 27, and C represents a position at which the lug is parallel with the spacing between fingers 28 and is thus totally unlatched or unlocked with respect to the keeper 27 and can be raised out of the latching slot portion 29 thereof.

It will also be appreciated that a complete up and down movement of the plunger 15 is necessary for accomplishing a turning or rotating movement thereof, such that the latching lug 16 is turned from an entering or released position with respect to the latching slot 29 to a completely locked position therewithin and, vice versa. A double up and down movement in sequence is necessary for moving the plunger 15 through of rotation or from an unlocked, through a locked and back to an unlocked position. Although the cam surfaces are shown contoured for clockwise rotation of the plunger 15, it will be apparent that they may be contoured for counterclockwise rotation or turning movement, if desired. One up and down movement of the plunger 15 may be accomplished to rotate or turn the latching lug 16 from an entering position within the latching slot 29 of the keeper 27 to a fully locked position therein. Also, as above indicated, a further up and down movement is accomplished to rotate or turn the latching lug 16 from a fully locked position within the latching slot to a fully released or unlocked position therein.

FIGURES 6, 8 and 9 of the drawings show a device 10 of the invention as operatively-connected or mounted with respect to a lazy-tong or toggle type of lifting assembly 30. The assembly 30 has an upper pair of pivotally-connected lever or toggle arms 31 and 32, and a lower pair of pivotally-connected lever or toggle arms that serve as tong, grapple or grip arms 33 and 34. The toggle arms 31 and 32 of the upper pair are pivotally-connected at their outer ends by pivot pins 35 to outer ends of the arms 33, 34 of the lower pair. The upper pair 31 and 32 are centrally connected together by a through-extending pivot pin 37 which extends through hole portion 11c of the body 11 and additionally carries a suspension eyelet or lift clevis 38, such as used with an overhead crane or hoist.

As shown particularly in FIGURE 6, the body 11 of the control or latching device 10 is of oblong shape and one wing portion thereof that extends to the left is mounted on the pin 37 that extends through the hole portion 11b, and the other wing portion thereof is securely mounted on the arm 31 by a mounting pin 39 that extends through the hole portion 110. The oblong shape or construction of the main body 11 is such as to facilitate the connections and to aid in providing a substantially balanced suspended relation with respect to the center of gravity of the assembly 30, as represented by a vertical line through the clevis 38. The inner ends of the lower pair of arms 33 and 34 are centrally-pivotally connected together by a pivot pin 36.

In employing lifting assembly 30, such as illustrated in FIGURES 6, 8 and 9, it will be latch-retained in the open position of FIGURE 6 when it is suspended at clevis 38 under tension by a hoist cable or the like. At this time, the device 10 has its latching lug 16 in full locking engagement with fingers 28 of the slotted portion 29 of the keeper 27, and lower cam face or edge 19 is in latching engagement with the lower pair of latch pins 20 and 20'. When it is desired to lift an article such as an ingot 45, the assembly 30 is moved downwardly until its central portion, as exemplified by the pin 36, engages the article to thus cause the plunger to move upwardly and turn one eighth or 45 towards an unlocked position with respect to the keeper 27. The upper cam face or edge 18 engages the upper latch pin 23. This further slightly spreads the grapple arms 33 and 34 (see FIGURE 8). When tension is again applied to the hoist cable and the clevis 38, as exemplified in FIGURE 9, the plunger 15 moves to the downward position of FIGURES 1 and 2, thus turning it another eighth or 45 of a turn to a fully released or unlocked position with respect to the keeper 27.

When the plunger 15 is thus turned 90 by upward and downward movement to align latching lug 16 with the elongated opening between fingers 28 or of the latching slot portion 29 of the keeper 27, the lug 16 may be raised out of the keeper 27 by applying raising tension on the clevis 38. This enables the tong-like assembly 30 to, in effect, spread upwardly and produce a strong gripping action upon the article 45 through the agency of the grapple arms 33 and 34. The article 45 may then be hoisted and moved to any suitable location in a plant and then released by releasing the tension on the clevis 38. The latching lug 16 may then again enter the keeper 27, and on entering, may be turned in progressively 45 steps to 90 at which it is in a fully locked position within the keeper.

An important feature of the present invention is the provision of a construction such that the latch pins 20, and 23 can be readily removed endwise out of the central open portion of the housing 12 and completely, if desired, from the housing; they can thus be replaced as needed. The operating cam 17 can also be replaced by moving the lower pair of latch pins 20 and 20 endwise-outwardly, in order that the cam 17 may be cleared to move downwardly along and out of the bore portion 11a of the main body 11. It will be noted that the cam 17 has an outer diameter corresponding to the outer diameter of the central portion 15a of the plunger 15. If the cam 17 is an integral part of the plunger, then both may be replaced as a unit. On the other hand, if the cam 17 is a separate or sleeve part and is secured as by welding, sweating or other suitable means, such as a wedge pin, on the reduced end portion 150 of the plunger, it will only be necessary to slip on and secure a new sleeve-like cam on the old plunger 15. It is thus apparent that the parts of major wear and tear of the device 10 may be readily replaced without requiring a replacement of the whole device or of other parts which are not directly concerned from the standpoint of necessary maintenance.

Although an operating embodiment of the inventive device has been shown and described, it will be apparent to those skilled in the art that various modifications, changes, additions, and adaptations may be accomplished on the disclosed device.

I claim:

1. In a control device for a toggle type of lifting device having a keeper provided with a latching slot portion, a main body provided with a bore portion extending centrally therethrough, a housing projecting upwardly from said main body in alignment with said bore portion and having a pair of opposed closed sides and a hollow central portion, an upper latch pin extending from said closed sides across the hollow central portion of said housing, a pair of lower latch pins extending in an opposed relation from said closed sides and terminating in an endwise-spaced relation within the hollow central portion of said housing, an operating plunger having a cylindrical central body portion slidably-positioned in and extending vertically along said bore portion of said main body, a latching lug on the lower end of said plunger for movement into and out of latching engagement with the latching slot portion of the keeper,

said plunger having an upper end portion of reduced diameter that extends above said pair of lower latch pins, a cam on said reduced upper end portion of said plunger operatively-positioned within the hollow central portion of said housing, said cam having an upper cam face thereon shaped to turn said plunger in one direction on and to latch-engage with said upper latch pin when said plunger is moved upwardly within said bore portion, said cam having a lower cam face to engage said pair of lower latch pins and shaped to further turn said plunger in the same direction on and to latchengage with said pair of lower pins when said plunger is moved downwardly within said bore portion, and said pair of lower latch pins having inner end portions of concave shape positioned in an endwise-opposed relation on opposed sides of and to slidably-guide said upper end portion of said plunger.

2. In a control device for a toggle type of lifting device having a keeper provided with a latching slot portion, a main body provided with a bore portion extending centrally therethrough, a housing projecting upwardly from said main body in alignment with said bore portion and having a pair of opposed sides defining a hollow central portion, an upper cross-extending latch pin positioned to extend from and between said opposed sides across the hollow central portion of said housing, a pair of lower latch pins positioned in a downwardly-spaced-aligned relation with respect to said upper pin and extending in an opposed relation from said opposed sides to terminate in an endwise-spaced relation with respect to each other within the hollow central portion of said housing, an operating plunger having a central body portion endwise-slidably and rotatably positioned in and extending along said bore portion, a latching lug on the lower end of said plunger for turning movement with said plunger into and out of latching engagement with the latching slot portion of the keeper, said plunger having an upper end portion extending into the hollow central portion of said housing adjacent to and upwardly beyond said pair of lower latch pins, a dual-faced cam secured on said upper end portion and operatively-positioned within the hollow central portion of said housing for movement therein between said upper latch pin and said pair of lower latch pins, said cam having an upwardly-facing cam face shaped to turn said plunger on and to latch-engage with said upper latch pin when said plunger is moved upwardly-within said bore portion, said cam having a lower downwardly-facing cam face to engage said pair of lower latch pins to turn said plunger in the same direction on and to latch-engage with said pair of lower latch pins when said plunger is moved downwardly within said bore portion, the spacing between said upper and said pair of lower latch pins being greater than the width of said cam between said upper and lower cam faces thereof to provide turning clearance for said lower cam face with respect to said pair of lower latch pins when said upper cam face is in engagement with said upper latch pin and to provide turning clearance for said upper cam face with respect to upper latch pin when said lower cam face is in engagement with said pair of lower latch pins, and said upper and said lower latch pins having means cooperating with said housing to remova-bly-secure them for endwise movement into and out of fixed positions therein.

3. In a control device as defined in claim 2, each of said pair of lower latch pins having a concave inner end portion that slidably-guidably engages said upper end portion of said plunger.

4. In a control device as defined in claim 2, said upper end portion of said plunger being of reduced diameter with respect to said central body portion thereof, said pair of lower latch pins having an inner end spacing with respect to each other that corresponds to the reduced diameter of said upper end portion, and said cam having an outer diameter substantially corresponding to the diameter of said central body portion.

5. In a control device as defined in claim 4, said pair of lower latch pins having inner end portions of complementary shape with respect to said upper end portion for guiding said plunger during its upward and downward and rotating movements.

6. In a control device for a toggle type of lifting device having a keeper provided with a latching slot portion, a main body provided with a bore portion extending centrally therethrough, a housing projecting upwardly from said main body in alignment with said bore portion and having a pair of opposed closed sides and a hollow central portion, an upper latch pin extending from said closed sides across the hollow central portion of said housing, a pair of lower latch pins extending in an opposed relation from said closed sides and terminating in an endwise-spaced relation within the hollow central portion of said housing, an operating plunger having a cylindrical central body portion slidably-positioned in and extending vertically along said bore portion of said main body, a latching lug on the lower end of said plunger for movement into and out of latching engagement with the latching slot portion of the keeper, said plunger having an upper end portion of reduced diameter that extends above said pair of lower latch pins, a cam on said reduced upper end portion of said plunger operatively-positioned within the hollow central portion of said housing, said cam having an upper cam face thereon shaped to turn said plunger in one direction on and to latch-engage with said upper latch pin when said plunger is moved upwardly within said bore portion, said cam having a lower cam face to engage said pair of lower latch pins and shaped to further turn said plunger in the same direction on and to latchengage with said pair of lower pins when said plunger is moved downwardly within said bore portion, said cam having an outer diameter substantially corresponding to the outer diameter of said central portion of said plunger, whereby said cam may be inserted and removed from said central open portion along said bore portion after said pair of lower latch pins had been moved endwise out of the hollow central portion of said housing, said upper latch pin and said pair of lower latch pins being endwiseslidable within said housing into and out of the hollow central portion thereof, and mounting pieces removablysecured on said housing and having a tongue and groove engagement with said latch pins for removably-securing them within said housing.

7. In a control device for a toggle type of lifting device having a keeper provided with a latching slot portion, a main body provided with a bore portion extending centrally therethrough, a housing projecting upwardly from said main body in alignment with said bore portion and having a pair of opposed closed sides and a hollow central portion, an upper latch pin extending from said closed sides across the hollow central portion of said housing, a pair of lower latch pins extending in an opposed relation from said closed sides and terminating in an endwisespaced relation within the hollow central portion of said housing, an operating plunger having a cylindrical central body portion slida-bly-positioned in and extending vertically along said bore portion of said main body, a latching ing on the lower end of said plunger for movement into and out of latching engagement with the latching slot portion of the keeper, said plunger having an upper end portion of reduced diameter that extends above said pair of lower latch pins, a cam on said reduced upper end portion of said plunger operatively-positioned within the hollow central portion of said housing, said cam having an upper cam face thereon shaped to turn said plunger in one direction on and to latch-engage with said upper latch pin when said plunger is moved upwardly within said bore portion, said cam having a lower cam face to engage said pair of lower latch pins and shaped to further turn said plunger in the same direction on and to latchengage with said pair of lower pins when said plunger is moved downwardly within said bore portion, and said housing having a pair of opposed side 'walls removablysecured to said closed sides to fully enclose the hollow central portion thereof.

References Cited UNITED STATES PATENTS 2,856,781 10/1958 Forbes 7456 FOREIGN PATENTS 492,867 9/1938 Great Britain. 642,100 8/ 1950 Great Britain.

EVON C. BLUNK, Primary Examiner D. D. WATTS, Assistant Examiner

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