US3674302A

US3674302A - Ingot and mold handling tongs

Info

Publication number: US3674302A
Application number: US118102A
Authority: US
Inventors: Robert Douglas Mutch
Original assignee: Dominion Bridge Co Ltd
Current assignee: Dominion Bridge Co Ltd
Priority date: 1970-12-10
Filing date: 1971-02-23
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: CA906026A

Abstract

A pair of bell cranks pivoted to a support member provide a pair of crossed upper arms for suspension from a crane hook, and a pair of transversely spaced lower arms equipped with opposing jaws. The jaws are provided with sockets and with bits to selectively engage lifting lugs of an ingot mold with the sockets, or to grip an ingot with the bits. An actuating line connected to the support member moves the arms toward or away from each other, and parallel motion links between the support member and the jaws maintain a constant angular attitude of the sockets and bits throughout the range of movement of the arms.

Description

C United States Patent {15] 3,674,302

Mutch 1 July 4, 1972 [54] INGOT AND MOLD HANDLING TONGS 1,851,923 3/1932 McQuigg ..294/115 I 3,384,410 5/1968 Belford ..294/112 [72] Inventor: Robert Douglas Mutcli, Niagara Falls, On-

tam) Canada Primary ExaminerEvon C. Blunk 731 Assignee: Dominion Bridge Company Limited, Mon- Amman Examiner-Johnny Heal, Quebec, Canada Attorney-Fetherstonhaugh & Co.

[22] Filed: Feb. 23, 1971 57 ABSTRACT [21] Appl. No.: 118,102 A pair of bell cranks pivoted to a support member provide a pair of crossed upper arms-for suspension from a crane hook, and a pair of transversely spaced lower arms equipped with 3 Foreign Apphcatlon Pnomy Data opposing jaws. The jaws are provided with sockets and with Dec. 10, 1970 Canada 100,341 bits to selectively engage lifting lugs 01f an ingot .mold with the sockets, or to grip an ingot with the bits. An actuating line [52] U.S. Cl ..294/118, 294/111 connected to the support member moves the arms toward or [51] Int. Cl. ..B66c 1/50 way from each other, and parallel motion links between the [58] Field of Search ..294/67 BC, 67 DA, 67 DC, 106, support member and the jaws maintain a constant angular at- 294/111, 112, 114, 115, 118, 119 titude of the sockets and bits throughout the range of move ment ofthe arms.

56 R f 't d 1 e erences e 8 Claims, 6 Drawing Figures UNITED STATES PATENTS 681,518 8/1901 Stevens ..294/112 PATENTEDJUH 1912 3.674302 SHEET 10F 5 INVENTUR Robert Douglas MUTCH 1 TEN T AGEX TS PATENTEDJUL] I972 SHEET 2 OF 5 INVENTOR Robert Douglas MUTCH F/c. Z v

PATENT AGENTS P'A'TEN'T'EDJUM 1972 3. 674, 302

- sum 3 or s INVENTOR 28L Robert Dougllus MUTCH 'F/G. W V4 PA TEN T AGENTS PATENTEDJUL 4 I972 SHEET U 0? 5 INVENTOR Robert Douglas MUTGH lN GOT AND MOLD HANDLING TONGS This invention relates to new and useful improvements in grapple-type hoist-line implements, and in particular the invention concerns itself with tongs especially adapted for handling metal ingots and ingot molds.

In steel mill practice, for example, it is customary to use a large, slow-moving stripper crane to sort ingots and/or ingot molds in random sequence after stripping, for further processing of the ingots and reconditioning of the molds. This procedure is time-consuming because of the slow movement of the stripper crane and moreover, when the stripper crane is used for ingot and mold sorting, it is not available for its primary duty of stripping ingots from molds. In some conventional instances where separate devices were utilized for ingot or mold handling, they have been limited to handling either ingots or molds, but not both in a selective manner.

The principal object of this invention is to greatly facilitate the ingot and mold sorting procedure so that it may be carried out rapidly and indiscriminately among both ingots and molds, without utilizing the conventional stripper crane. This object is attained by the provision of a hoist-line implement in the nature of tongs which may be suspended from and expeditiously actuated by a light-capacity, high-speed crane, the tongs having pivoted jaws equipped with both sockets to engage lifting lugs of an ingot mold and bits to grip an ingot, so that both ingot molds and ingots may be handled selectively by the same tongs.

The pivoted jaws are supported by arms of the tongs, which arms are movabletoward and away from each other, not only in order to apply the tongs to and remove the same from the work, but also in order to accommodate ingots and molds of different diameters or thicknesses. An important feature of the invention resides in providing the tongs with parallel motion links which maintain the jaws at a constant angular attitude relative to each other, regardless of Whether the arms of the tongs are drawn toward each other or spread apart, thus assuring that the sockets and the bits on the jaws of the tongs are always properly oriented to engage the work.

Another important feature of the invention is that the jaws of the tongs are arranged so that they may be readily inserted between and engaged with ingots or molds which are standing close together or, in a modified embodiment, that they may be engaged with ingots or molds which are lying in any position other than standing vertically.

With the foregoing more important object and features in view and such other objects and features which may become apparent as this specification proceeds, the invention will be understood from the following description taken in conjunction with the accompanying drawings, in which like characters of reference designate like parts, and in which:

FIG. 1 is an elevational view showing one embodiment of the ingot and mold handling tongs of the invention, the same being applied to an ingot illustrated by dotted lines;

FIG. 2 is an elevational view of the tongs, taken from one side ofFlG. 1;

FIG. 3 is a fragmentary elevational view showing the tongs of FIG. 1 applied to a mold;

FIG. 4 is an elevational view showing a modified embodiment of the tongs applied to an ingot;

FIG. 5 is a fragmentary elevational view showing the tongs of FIG. 4 applied to a mold; and

FIG. 6 is a view, largely diagramatic, showing the hoisting and actuating lines of the tongs.

Referring now to the accompanying drawings in detail, more particularly to FIGS. 1 and 2, the general reference numeral l0 designates one embodiment of tongs which, in accordance with the invention, may be used selectively for sorting, lifting or other handling of both ingots and ingot molds. The tongs comprise a horizontally elongated support member 12 having a pair of transversely spaced pivot pins 13 on which are mounted a pair of co-acting bell cranks 14. These bell cranks include a pair of transversely spaced lower arms 15 located below the support member 12, and a pair of mutually crossed upper arms 16 above the support member.

A suspension block 17 has a pair of suspension links 18 pivoted thereto as at 19, the links 18 extending downwardly from the block in mutually divergent relation and having their lower ends pivoted to the respective upper arms 16 as at 20. The block 17 is adapted to be suspended from a hook 21 of any suitable light-capacity, high-speed overhead crane which serves to raise or lower the tongs as a whole. A tong actuating line 22 passes freely through the crane hook 21 and is connected centrally to the support member 12, as by an anti-friction swivel connection 23 which permits the tongs to turn about a vertical axis represented by the line 22 without twisting that line. Conventional crane mechanism, hereinafter briefly explained in connection with FIG. 6, is used to raise or lower the crane hook 21 and to haul in or pay out the actuating line 22 independently of the raising or lowering of the hook. Thus, it will be apparent from the foregoing that when, for example, the support member 12 is pulled upwardly toward the suspension block 17 by the actuating line 22, the geometric arrangement of the tong components is such that the lower arms 15 of the bell cranks 14 will be moved apart from each other to open the tongs. Conversely, when the member 12 is lowered relative to the block 17, the arms 15 will be moved toward each other to close the tongs. When the tongs simply hang without any load or restraint, the arms 15 are as close together as possible but are still transversely separated by a distance sufficient to accommodate the smallest diameter or thickness of a mold or ingot which the tongs are intended to handle.

A pair of jaws 24 are pivotally connected to the lower ends of the respective lower arms 15 by suitable pivot pins 25. Each jaw is in the form of a bell crank and includes a substantially flat, vertical lower portion 24a formed with a closed opening defining a loop or socket 26 as shown in FIG. 2, these loops or sockets in the two jaws being adapted to receive the usual lifting lugs 27 on the opposite sides of an ingot mold 28 when the tongs are applied to the mold as shown in FIG. 3. Above the loops or sockets 26, the jaws 24 are equipped with inwardly directed, opposing bits 29 which are still located below the jaw pivots 25 and are adapted to grip the opposite sides of an ingot 30 when the tongs are applied to an ingot as shown in FIG. 1.

The jaws 24 also include laterally outwardly projecting lever-like portions 24b and these have connected thereto by pivots 31 the lower ends of a pair of parallel motion links 32, the upper ends of which are connected to the ends of the support member 12 by the pivot pins 33. The distance from the pins 33 to the bell crank pivots 13 is the same as that from the pivots 31 to the

jaw pivots

31 and 33 corresponds to that between the

pivots

25 and 13. Thus, a parallelogram linkage is provided which maintains the jaws 24 at a constant angular attitude relative to each other throughout the entire range of movement of the arms 15 together or apart. As a result, the jaw portions 24a remain substantially vertical, the loops or sockets 26 in the jaws are always properly aligned, and the bits 29 are always oriented toward each other, notwithstanding the relative position of the arms 15, so that the loops 26 and the bits 29 may come into proper engagement with a mold or an ingot, as the case may be, not only when the work is to be lifted, but also during the lifting operation in which the tongs may be called upon to accommodate ingots and molds of different diameters or thicknesses, as for example, in a range from between 13 and 44 inches.

In operation, for example if an ingot 30 is to be lifted, the tongs are opened by hauling in the actuating line 22 so that the lower arms 15 are spread apart sufficiently for the ingot to fit in between the opposing bits 29 on the jaws 24. As the tongs are lifted by the crane hook 21, the arms 15 are drawn toward each other and the ingot 30 is gripped by the bits 29. The gripping force at the bits varies over the range of movement of the arms 15 but has a minimum value controlled by the geometry of the arms and links. Gripping is initiated by friction between the bits and the ingot, due to the weight of the arms and links tending to close the tongs. As soon as the crane hook starts to lift, this friction increases the upward force required at the crane hook, which in turn increases the bit pressure. This rises very rapidly to a value which either indents the ingot or exceeds the friction force required to support the weight of the ingot. In either event, the ingot can then be lifted from the ground or floor.

When lifting an ingot mold 28, the tongs are opened to spread the arms 15 sufficiently for the vertical lower portions 24a of the jaws 24 to straddle the mold at the outside of the lifting lugs 27. The arms 15 are then moved toward each other so that the lifting lugs 27 of the mold are received in the sockets or loops 26 of the jaws, as shown in FIG. 3, and as the mold is lifted, the tendency of the tongs to close forces the lower jaw portions 240 firmly against the sides of the mold.

It is to be noted that in lifting either ingots or molds, the parallel motion links 32 maintain the two jaws 24 at the same angular attitude, regardless of the extent to which the arms 15 are spread apart, thus assuring that the bits 29 are always oriented opposite to each other for gripping an ingot therebetween, and that the jaw portions 240, in the sockets 26 of which the mold lugs 27 are seated, are always vertically disposed to properly fit the lugs and press against the sides of the mold. Since the bits 29 as well as the sockets 26 in the jaw portions 24a are located below the fulcrums 25 of the jaws 24, the tendency of the arms 15 to close creates a tendency for the lower jaw portions 24a to turn outwardly away from the work, and this tendency is counteracted by the links 32 which resist compression. It will be also observed that the substantially flat, vertical form of the lower jaw portions 24a enables them to be lowered between ingots or molds which stand close together, with resulting economy of space.

This form and the parallel link movement also mean that the lower jaw portions 24a with the sockets 26 therein do not in terfere with ingots which are lifted by the bits 29 as long as the sides of the ingots are predominantly in one plane.

Reference is now drawn to FIGS. 4 and 5 which show a somewhat modified embodiment of the tongs. To the extent that the parts substantially correspond, the same reference numerals designate the same parts as in the embodiment already described. The tongs of FIGS. 4 and 5 are primarily intended to handle what are known as hot-top ingots by gripping them at a reduced section or hot-top" which is subsequently discarded. The size of the ingot below the reduced hot-top precludes the possibility of the jaws of the tongs extending more than a few inches below the ingot gripping bits and accordingly, differently arranged jaws are necessary in order to provide sockets for the lifting lugs of ingot molds.

This is shown in FIGS. 4 and 5 where the jaws 124 are pivoted to lower ends of the arms by the pins and the bits 29 are provided on the jaws below the pins 25, but the jaws are extended upwardly above the pins, where they are formed with upwardly and inwardly open sockets 126 to receive the mold lifting lugs 27, as shown in FIG. 5. In this instance the tendency of the arms 15 to close creates a tendency of the upper, socketed portions of the jaws 124 to turn outwardly about the pivot pins 25, and that tendency is counteracted by the links 32 which resist tension.

FIG. 4 shows the tongs applied to an ingot with the grips 29 gripping the sectionally reduced hot-top portion 30a of ingot, an additional advantage of the arrangement of the jaws 124 being that they may readily handle ingots which are lying on their sides rather than standing vertically.

The tongs of FIGS. 4 and 5 may be suspended from the crane hook 21 by the block 17 and links 18 as in FIGS. 1-3, but FIG. 4 shows a somewhat modified suspension arrangement wherein the upper ends of the suspension links 118 are connected by pivots 119 to a tension link 117 which is more readily detachable from the hook 21 than the aforementioned block 17. FIG. 6 is a largely diagramatic view of the hoisting and actuating lines of the tongs T, which may be the tongs of FIGS. l3 or those of FIGS. 4-5. The tongs actuating line 22, after passing through the crane hook 21, is attached to a tongs actuating sheave block 40 which is reeved into a tongs actuating hoist rope 41. One end of the rope 41 is wound on the main hoist drum 42 of the crane and leads off the same side of the drum as the main hoist ropes 43 which pass around the main sheave block 44 of the crane hook 21. The other end of the rope 41 is wound on a tongs actuating drum 45 which is driven by means independent of that driving the main hoist drum 42.

It will be apparent that rotation of the main hoist drum 42 in the appropriate direction will bodily raise or lower the tongs without changing the transverse spacing of the arms 15. However, if the tongs are to be opened or closed, the actuating drum 45 is rotated in the appropriate direction, regardless of whether or not the main drum 42 is stationary, thus causing the arms 15 to be moved closer together or further apart.

As already indicated, the hoisting and actuating line arrangement as in FIG. 6 is conventional, and while it is well suited for use with the tongs of the invention, the crane hook 21 may be simply raised and lowered by a conventional hoist line and the tongs actuating line 22 may be omitted. In such event, means may be provided on the tongs themselves for raising and lowering the support member 12 relative to the suspension means 17 (or 117), as for example a hydraulic or pneumatic cylinder reacting between the support member and the suspension means, or a motor-operated screw mechanism, or the like, such a cylinder or mechanism being remotely controlled to open or close the tongs, while permitting the tongs to be raised and lowered by the crane hook.

While in the foregoing there have been described and shown the preferred embodiments of the invention, various modifications and equivalents may be resorted to, within the spirit and scope of the invention as claimed.

What is claimed as new is:

1. Tongs for selectively handling ingots and ingot molds, said tongs comprising in combination, a horizontally elongated support member, a pair of horizontally spaced parallel pivot pins provided on the end portions of said support member, a pair of coacting bell cranks mounted on the respective pivot pins, said bell cranks including transversely spaced lower arms below the support member and mutually crossed upper arms above the support member, means connected to said upper arms for suspension of the tongS from a crane hook, tong actuating means connected to said support member for movement thereof relative to said suspension means whereby said lower arms may be moved toward and away from each other, a pair of opposing jaws pivoted to said lower arms, said jaws being provided with sockets for engagement with lifting lugs of an ingot mold, opposing bits provided on saidjaws for gripping engagement with an ingot, and parallel motion links pivoted to the respective ends of said support member and to the respective jaw whereby to maintain the jaws at a constant angular attitude to each other throughout the range of movement of said lower arms.

2. The device as defined in claim 1 wherein said tong actuating means include an actuating line connected to said support member.

3. The device as defined in claim 1 together with pivots connecting said jaws to the lower ends of said lower arms, said bits being provided on said jaws at points below said pivots and said sockets being provided in said jaws below said bits.

4. The device as defined in claim 3 in which said jaws have substantially flat vertical lower portions in which said sockets are provided.

5. The device as defined in claim 4 which is further characterized in that said lower portions of said jaws are in the form of closed loops defining said sockets.

6. The device as defined in claim 1 together with pivots connecting said jaws to the lower ends of said lower arms, said bits being provided on said jaws at points below said pivots and said sockets being provided in the jaws above said pivots.

7. The device as defined in claim 6 which is further characterized in that said jaws are formed with inwardly and upwardly open seats defining said sockets.

8. The device as defined in claim 1 wherein said jaws include lever-like portions projecting laterally outwardly, said parallel motion links being connected to said lever-like portions of said jaws.

Claims

1. Tongs for selectively handling ingots and ingoT molds, said tongs comprising in combination, a horizontally elongated support member, a pair of horizontally spaced parallel pivot pins provided on the end portions of said support member, a pair of coacting bell cranks mounted on the respective pivot pins, said bell cranks including transversely spaced lower arms below the support member and mutually crossed upper arms above the support member, means connected to said upper arms for suspension of the tongS from a crane hook, tong actuating means connected to said support member for movement thereof relative to said suspension means whereby said lower arms may be moved toward and away from each other, a pair of opposing jaws pivoted to said lower arms, said jaws being provided with sockets for engagement with lifting lugs of an ingot mold, opposing bits provided on said jaws for gripping engagement with an ingot, and parallel motion links pivoted to the respective ends of said support member and to the respective jaw whereby to maintain the jaws at a constant angular attitude to each other throughout the range of movement of said lower arms.