US 2229800 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Jan. 2s, 1941.
W. T. DEAN TONGS Filed March 2o, 19:59 v
/ l l FISE;
Patented Jan. 28,' 1941 UNITED STATES PATENT oEFlcE 'roNGs y william r. man, Gary, ma. Application Max-cazo, 1939, serial No. 962,974 4 claims. (ci. 294-106) This invention relates to tongs as used especially in connection with soaking pltcranes for handling ingots and the like in the manufacture of steel and, particularly. to improved tongs for o such use and improved grips therefor.
Various types of tongs have been suggested and used in connectiongivith cranes for placing heavy lngots, bloomsand the like in soaking vpits and removing them therefrom, but some of these tongs are entirely unsatisfactory and are deficient in many respects. the gripping force is limited by inadequate leverageof the tongs, resulting in frequent dropping of cold ingots which, ofcourse, results in damage l5 to the tracks of the crane or other associated equipment, and also endangers the lives of the workmen. Also, pointed bits are generally used to grip the ingots and they are forced into they walls of .the ingot with such pressure as to result in deep bit marks therein which are undesirable, and diiiicult, as well as expensive, to remove. Furthermore, the life of such bits is short and they require frequent replacing or redressing which is inconvenient and expensive.
2Q Itis one of the objects of the present invention to provide improved tongs which will velectively grip the ingots or objects to be moved, thereby eliminating -the danger of the dropping therecf.`v
It is another object of the invention to provide improved tongs which are simple and inexpensive in their construction and, at thesame time, tongs which can be quickly and convenient-ly maintained and replaced.
It is a further object of the invention to provide improved tongs having grips which will not mark the ingot or object to be moved and which will not release their grip thereon until theingot 4o or obiect has'been properly and safely placed.
It is'atillanother object` of .the present invention to provide improved grips for such tongs in which the gripping force is determined by the weight of the ingot or object held thereby, and
increases relative to theA weight thereof. f
Various other objects and advantages of this invention will be more apparent in the lcourse of the following specication and will be particularly pointed out in the appended claims.
In the accompanying drawing there is shown. for the purpose of illustration, one embodiment which my invention may assume in practice.
In the drawing:
Figure `1 is a vertical section through the improved tongs assembly of my invention and part In most of the known tongs,v
of the soaking pit crane withfwhich'it is incorporated;
Figure 2is a vertical section through the end of one of the tongs showing one of the improved grips of my invention in its normal position there in; and.
Figure 3 is a section taken on the line III-III of Figure 2.
The improved tongs of my invention are adapted to be incorporated preferably with av soakingV m pit crane of a known type which is usually disposed above a row of soaking pits and adapted toy run ltherealong on suitable tracks for the purpose of positioning the same opposite any one of the soaking pits as desired. Such cranes usually have 1., arranged therewith a vertically disposed ram 2', a portion of which is shown in Figure 1 of the drawing, which is adapted n forv vertical movement thereon and is raised and lowered by suita'ble mechanism (not shown). v
There is arranged'in the lower part of the ram 2, a sleeve-like rotatable bearing member@ having a gear l secured thereon intermediate itsV length. There is axially arranged withinl .the ram 2 and bearing member 3, a vertically extend- '25 ing shaft 5 having a gear 6 secured to the upper end thereof above theend of the ram 2 and .-a coupling or suitable connecting member 1 carried by its lower end below the end of the bearing member 3. The gear 6 is adapted to mesh with` 30 a gear 8 arranged on the shaft] of amotor 9 which is suitably mounted on the side of the ram 2, and adapted to revolve the shaft 5. The'gearl l on the bearing member 3 is adapted to mesh with a gear I0 securely arranged on the lower end of a Vvert/ical shaft I2 suitably mounted preferably on the side of Ithe ramv 2 opposite the motor 9. There is also securely arranged on the shaft I2 intermediate its length another gear I3 which is adapted to mesh with a gear I4 carried by the shaft of a gear reducer I5 which'is driven by a motor I6, both of which are also disposed on the side of the ram 2 and the assembly associated therewith. The motor I6 together with the gear reducer I5 is adapted to revolve the bearing mem- 45 ber 3.
According -to the present invention, there is arranged below the bearing member 3 a tongs box or housing Il which is removably `supported by and attached to, by means of pins or bolts I8, a 50 yoke member I9 securely arranged on the lower end of the bearing member 3. 'I'here is arranged on `the lower end of the tongs box I1, a pair of tongs 20 which are pivotallyattached intermediate thereto preferably by means of bolts or pins 55 air 2|. The upper ends of the .tongs 23 are pivotally attached to a yoke member 22 by means of toggle levers 23 which are adapted to control the tongs opening upon movement thereof. There is arranged axially of the tongs box or housing I1 and attending -through the yoke member 22, a threaded shaft or screw 24 having its lower end journaled at 2l in the lower end of the tongs box and its upper end journaled at j23 in the upper end thereof. There is securely arranged on the upper end of the threaded shaft 24 a cooperating coupling part 21 which is adapted to engage with the connecting member 1 on the lower end of the drive shaft l. There is mounted on the threaded shaft 24 a movable nut 23 which is connected to the yoke member 22 preferably by means ofa pair of levers 23 oppositely disposed thereon and pivotally attached to the nut at and to the yoke memberat 3|. v
There is arranged in the lower ends of each of the downwardly extending arms of the tongs 23 an eccentric grip 32, the construction of which is one of the most important aspects of the invention. These grips are preferably made from a suitable heat resisting alloy and are preferably cast or forged blocks and are pivotally arranged in the tongsends by means of pins or bolts 33. Each of these grips has an arcuated front gripping surface which is preferably serrated as shown at 34 and preferably has heel portions 35 which are adapted to act as counterweights for keeping the upper edge 36 thereof normally `in ycontact with the stop portion 31 of the toggle arms. a i
The radius Rz of arcuation of the upper portion of the front surface of each of these grips is preferably greater than the radius R1 of arcuation of the lower portion thereof. The center of arcuation of the radius R1 is preferably the pivotal center of each of the grips 32 and the center of arcuation of the radius R2 is `preferably on a horizontal plane therewith and positioned rearwardly thereof, as is clearly shown in Figure 2 of the drawing. It will be seen that, with the grips constructed in such a manner, the serrated surfaces of the grips, as the tongs are moved upwardly, will bite into the surface of the ingot, bloom or the object to be moved with a force which may be many times greater than the weight of the object being held thereby. Thus, it will be seen that, the heavier the ingot or the bloom, the more force there will be exerted by the grips to hold the same. It is the purpose of the counterweighted heels 35 to return the grips to the short radius or free position after the ingot or object has been placed and the weight removed therefrom and the tongs opened..
It will be understood that it is the function of the threaded shafts 24 to open and close the tongs upon rotation thereof through the action of the nut 23, links 29, yoke member 22, and toggle levers 23. The shaft 21 is adapted to be v rotated by means of the shaft 5 through the action of the gears 6 and 8 and the motor 9. l It will also be understood that the entire tongs assembly is adapted to be rotated by means of the bearing 'members 3 'through the action of the gears 4 and I 0, the shaft I2, the gears I3 and I4, the reducer I5, and the motor I6.
VIn operation, the tongs are adjusted as clescribed by the turning of the threaded shaft 24 so that the. opposed surfaces of the grips 32 just contact the surface of the ingot bloom or object to b e moved. It will then be seen that, as the ram together with the complete assembly is moved upwardly, the eccentric grips 32, due to the pivotal construction thereof. will tend to be moved toward each other, thereby biting into the surface of the ingot.
It will be seen that the efficacy of the invention depends primarily upon the eccentric grips and it is preferable that there be no lost motion between the working parts of the tongs assembly so that they maybe held in aflxed and sturdy position in `order to operate properly. Therefore, the use of short heavy toggles is recommneded.
' The tongs assembly is often subjected to excessive heat and it is preferable that the bearings and guides bevof the embedded self-lubricating type and the threaded screw 24 be made from a heat resisting alloy.
As a result of my invention, it will be seen that the entire tongs assembly may be easily and quickly removed from the end of the'ram merely by-removing the two pinsy or bolts I3, whereupon another complete tongs assembly may be quickly attached thereto whenever it is necessary to handle ingots, blooms or other objects differing greatly in size. It will also be seen that the grips 32 may be quickly changed by removing the pins 33 whereupon the serrated gripping surfaces may be redressed, or the grips may be replaced with new grips if desired. It is-preferable that the gripping front surfaces of the grips be wide enough so that only shallow surfacevindentations are made in the ingots even when they arevery hot.
While I have shown and described one embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other forms may bedevised within the scope of my invention, as defined in the appended claims.
l. Tongs of the class described having a grip` of 'each of the gripping surfaces thereof coinciding with their pivoted centers and the radius of arcuation ofthe upper portion of each of the gripping surfaces being greater than the radius of arcuation of the lower portion thereof and with the center of the radius of arcuation of said upper portion being positioned rearwardly of said pivoted centers.
3. Tongs of the class described having a grip pivotally attached to each of the legs adjacent the ends thereof, each of said grips being pivoted centrally thereof and having a. counterweight portion arranged on the outer side thereof for returning the same to their normal positions and an arcuated and serrated gripping surface on the inner side thereof with the radius of arcuationcf the upper portion of the gripping surface of each of the grips being greater than the radius of arcuation of the lower portions thereof, and a stop portion carried by each of said legs with which the respective grips carried thereby are adapted to cooperate to maintain the same in their normal positions.
4. Tongs of the class described having a, grip pivotally attached to each of the legs adjacent the ends thereof, each of said grips being pivoted centrally thereof and having a. counterweight portion arranged on the outer side thereof, and an arcuated and serrated gripping surface on the inner side thereof with the center of the radius of arcuation of the lower portion of each of the gripping surfaces of the grip coinciding with their pivoted centers and the radius of arcuation of the upper portion of each of the gripping surfaces being greater than the radius of arcuation of the lower portions thereof with the center of the radius of arcuation of each of the upper portions being positioned rearwardly of their respective pivoted centers, and a stopportion carried by said legs with which the respective grip pivotally carried thereby is adapted to cooperate to maintain the same in their normal positions. WILLIAM T. DEAN.