US1796304A - Tempering steel strip - Google Patents

Description

2 Sheets-Sheet 1 liwerl/fibr March 17, 1931. A. REMINGTON TEMPERING STEEL STRIP Filed April '7. 1928 Patented Mar. 17, 1931 UNITED STATES ALFRED M. REMINGTON, OF FITCHBUBG,

MASSACHUSETTS, ASSIGNOR TO SIMONDS SAW e 6 STEEL 00., OF 'FITCHBURG, MASSACHUSETTS, A CORPORATION OF MASSA CHUSETTS TEMPEBING STEEL STRIP Application filed April 7, 1928. Serial No. 268,112.

This invention relates to an improvement in method and apparatus for tempering steel and more particularly for so treating the forward end of a steel band.

Steel before being tempered is first hardened and then quenched and these preliminary operations disturb the arrangement of the molecules so that the steel is somewhat distorted as a result. In order to eliminate 10 these distortions the steel is placed under pressure and so held during the tempering operation. When so treated it has been found that as the temperature rises the molecules of the steel will rearrange themselves so 5 that the steel will emerge perfectly flat from the drawing furnace. After the forward end has passed through the furnace, the rest of the steel band may be drawn through without difiiculty by means of a gripper or crab,

the band being under pressure so that it is ironed flat, but it has heretofore been found impossible so to treat the forward end of the band that the entire band has been uniformly pressed and tempered. The crab can not grasp the forward end of the band until it has passed through the furnace and hence that end can not be ironed as is the rest of the band. Prior to this invention it has been found impossible to avoid heating the for- Ward end before putting it under pressure so that the distortions are not removed, and consequently it has been necessary to flatten the end by a supplementary treatment such as by hammering or by softening and retempering.

The primary object of this invention is to provide means for subjecting the forward end of the band to pressure before and during the tempering operation, thus producing a band of uniform flatness throughout, without the necessity of any supplementary treatment. -A further object of this invention is to provide means for feeding the forward end of the band rapidly into the tempering furnace and placing it under pressure before the heat of the furnace has had an opportunity appreciably to raise the temperature of that end.

One embodiment of the invention includes a movably mounted drawing furnace pro- Fig' 1 is a side elevation partly in section illustrating the first step of tempering the forward end of a steel band which has passed through the hardening furnace and been quenched and cleaned; 1

Fig. 2 is a side elevation of a drawing furnace illustrating in full lines the position of the furnace prior to the start of the end temporing operation and in dotted lines the position of the furnace when the end tempering operation is started;

Fig. 3 is a similar side elevation illustrating in dotted lines the position of the drawing furnace at the completion of the end tempering operation and in'full lines theposition to which the furnace is shifted in order to permit the crab to engage the end of the band;

Fig. 4 is an enlarged elevation of the rear end of the drawing furnace;

Fig. 5 is a side elevation of the drawing furnace, certain parts being shown in section along the line 5-5 of Fig. 4; and

Fig. 6 is a cross sectional view of the furnace taken along the line 6-6 of Fig. 5.

This invention is shown as employed in connection with the treatment of a continuous steel band from which a band saw is made. It will be understood, however, that this showing is merely illustrative and that the invention is capable of being employed in connection with the tempering of other material.

As shown in Fig. 1, the steel band 10 prior to the tempering operation is passed through a hardening furnace A and a quenching tank B and over a table C on which the metal is cleaned before entering the tempering or drawing furnace D. The band is positively moved through these various mechanisms by means of feed rollers 11 and 12, the rollers 11 being located at the mouth of the hardeuframe 22 to the bottom of which are secured rollers 23 which engage tracks 2% suitably supported by means not shown. The chamber 21 of the furnace may be heated by coal. oil, gas or other suitable means. The mouth 25 of the chamber 21 is partially closed by a gate 26 and the other end 27 is closed by swinging doors 28 which separate sufliciently to permit the material to leave the furnace after treating.

Within the heating chamber 21 of the furnace D is mounted a form 30 comprising a stationary bed 31 and a plurality of reciprocable presser members 32. Each of the members 32 is mounted upon a post 33 and may be raised and lowered in any suitable manner, hydraulic means 34 being illustrated diagrammatically in the drawing. One end 35 of the form extends out of the mouth 25 of the chamber for a reason to be pointed out below.

Since the temperin ordrawing furnace D is entirely enclosed within the frame 22 mounted upon rollers 23, it is free to move as a unit on the tracks 24. This movement may be caused by any suitable means, such as for instance a ram 40, see Figs. 1 and 2, including a piston rod 41 which is rigidly secured to a tongue 42 projecting downwardly from the frame 22 and which is reciprorated by hydraulic or other means. Secured to the projecting end 45 of the stationary bed 31 is a chain 46 adapted to be wound around a drum 47. A suitable weight 48 is attached to a cable 49 wound around the drum 47 in the opposite direction to balance the chain 46. At the end of the drum 47 is mounted a ratchet 50, the teeth 51 of which may be engaged by a pawl 52 which may be shifted into and out of engaging position by a lever 53.

As previously pointed out, the primary object of this invention is to provide means for tempering the forward end of a steel band and for placing that end under pressure before its temperature rises appreciably in the tempering furnace. The operation of the mechanism for that purpose will now be described.

Attention is first called to Fig. 2 which shows in full lines the furnace D in approximately its normal position with the presser members 32 raised. The band 10 is positively fed forward by the rollers 11 and 12 until the forward end of the baud enters or is about to enter the mouth 25 of the furnace. The ram 40 is then actuated to carry the furnace rapidly from the full-line position of Fig. 2 into the dotted'line position in which the end of the band enters the form 30 a distance approximately equal to the effective length of the furnace. As soon as the latter position is reached the presser members 32 are forced down to clamp the end of the hand against the bed 31 (see Fig. 1). This operation takes place very rapidly before the heat-in the tempering or drawing furnace has had an opportunity to raise the temperature of the band so that the forward end of the band is under ressure before any appreciable increase of its temperature takes place.

When the furnace has been shifted from the full line position of Fig. 2 into the dotted position of that figure, and the presser members 32 have been clamped down upori'bed 31, the relationship disclosed in Fig. 1 is attained and the tempering of the forward end of the strip started. During this operation the ram 40 is actuated and the furnace is drawn forward until it reaches the position shown in dotted lines in Fig. 3, in which it is held by the chain 46 through the engagement of the pawl 52 with one of the teeth 51 of the ratchet 50, when the tempering operation is completed, the presser members 32 are raised and the furnace returned by the ram 40 into an intermediate position as e. g.

the full-line position of Fig. 3. Since the end of the band is no longer clamped by the form 30 it will not be carried back by the furnace but will project out of the chamber 21 between the doors 38 far enough to be seized by a gripper or crab 60 which controls the further movement of the band.

The remainder of the band is now tempered in the following manner: The furnace D ma be held in the full-line position of Fig. 3 by the chain 46, ratchet 50 and pawl 52, the presser members 32 being immediately returned to lowered position to clamp the band 10 against the bed 31. The crab 60 is advancedby any suitable means (not shown) pulling the band through the furnace and since the band is clamped by the form 30 it is pressed and ironed and emerges from the temper-ing furnace entirely flat.

Since the end 35 of the form 30 projects into and beyond the mouth of the chamber 21 the band is subjected to pressure as soon as it is subjectedto drawing heat. The chain 46 is attached only to the bed 31 which is rigidly secured to the casing 20 in the usual manner and consequently all strain is resisted by the casing 20 and none is transmitted to the enclosing frame 22.

In the old method above referred to, the furnace D was stationary and the band was fed slowly onto the bed 31 by the feed rolls 11 and 12. Consequently when the band finally reached the position shown in Fig. 1 and the movable members 32 were clamped down, the

forward end of the band was heated before being subjected to pressure, which order of procedure is ineffective to iron out the distortion, it being necessary to subject the stock to pressure while the stock is bein heated. Accordingly, after the whole band rad been tempered it was necessary to flatten out the forward end either by hammering or by softening and retempering in a separate operation. The present method, however, eliminates this objection because the forward end of the band is quickly fed completely into the tempering furnace and placed under pressure before the tempering heat has had any appreciable effect upon it. The essence of the invention is, therefore, the method and apparatus of treating the forward end of the band by subjecting it to a tempering operation and a pressing operation, the pressing operation preceding the tempering operation.

While one means for carrying out this method has been shown and described, I am not limited thereto since it is obvious that other means could be devised without departing from the spirit and scope of the invention as set forth in the following claims.

I claim:

1. Method of treating a continuous strip of band stock in a hardening furnace and a drawing furnace consisting in feeding said stock slowly through said hardening furnace and in feeding the forward end of said stock rapidly into said drawing furnace a distance approximately equal to the effective length of said furnace.

2. Method of treating a continuous strip of band stock in a hardening furnace and a drawing furnace consisting in feeding said stock slowly through said hardening furnace and in feeding the forward end of said stock rapidlyinto said drawing furnace by shifting one of said furnaces toward the other furnace along the path of feeding of the stock.

3. Method of treating a continuous strip of band stock in a hardening furnace and a drawing furnace consisting in feeding said stock slowly through saidhardening furnace and in feeding the forward end of said stock rapidly into said drawing furnace by shifting said furnace in the direction opposite to that in which the stock is being fed a distance approximately equal to the effective length of said furnace.

4. Apparatus for tempering band stock comprising a drawing furnace having a stock passageway therethrou h, a presser form movable transversely 0 said passageway to press the stock during the drawing 0 eration, and means for moving the furnace back and forth longitudinally of said passageway to grip a length of stock and then travel with the stock while the latter is under pressure.

5. Apparatus for tempering band stock comprising hardening means, means for drawing the temper including mechanism for pressing the stock during the drawing operation, mechanism for feeding the stock through said means successively, and mechanism for moving one of said means relatively to the-other whereby a substantial length of the forward end of the stock may be quickly inserted into the drawing means. I

6. Apparatus for tempering band stock comprising a hardening furnace, a drawing furnace, a presser for ironing the stock during the drawing operation, means for continuously feeding the stock through the hardening furnace to the drawing furnace, and mechanism for moving the drawin furnace toward and from the hardening urnace a distance approximately equal to the effective length of the drawing furnace.

7. A tempering furnace having a heating chamber through which the material to be tempered travels, and a form in said furnace arranged in said chamber longitudinally thereof and comprising a stationary bed member and a movable presser member reciprocable relative to said bed member, the material passing between said members, one end of said form projecting from the mouth of said chamber.

8. A tempering furnace having a heating chamber through which the material to be tempered travels, a form in said chamber comprising a stationary bed member and a plurality of movable presser members, the material passing between said stationary and movable members, one end of said form projecting from the mouth of said passage,

9. A tempering furnace having a heating chamber through which the material to be tempered travels, a form in said chamber comprising a stationary bed member and a plurality of movable presser members, the material passing between said stationary and movable members, one end of said form projecting from the mouth of said passage, and means for advancin said movable presser members toward said stationary member to exert pressure upon said material.

10. A tempering furnace having a heating chamber through which the material to be tempered travels, a form .in said chamber comprising a stationary bed member and a plurality of movable'presser members, the

material passing between said stationary and movable members, means for moving said furnace and means for holding said furnace against movement in one direction.

11. A tempering furnace having a heating chamber through which the material to be tempered travels, a form in said chamber comprising a stationary bed member and a plurality of movable presser members, the material passing between said stationary and movable members, means for reciprocating said furnace and means at ached to said form for holding said furnace against movement in one direction.

12. A tempering furnace having a heating chamber and through which the material to be tempered travels, a form in said chamber comprising a stationary bed member and a plurality of movable presser members, the material passing between said stationary and movable members, one end of said form projecting from the mouth of said passage, means for reciprocating said furnace and means attached to the projecting end of the form bed member for holding said furnace against movement in one direction.

13. The combination of a plurality of furnaces for treating band stoci-q. means for continuously advancing a band of stock through one of the furnaces to and through the other furnace, the furnaces being relatively movable toward and from each other along the path followed by the stock in passing between the furnaces, means for effecting relative movement of the furnaces to bring them closer together as a band of stock is about to enter said other furnace so that a considerable length of stock may he suddenly introduced into the latter furnace,.presser members in the latter furnace and engageable with stock disposed therein, and means for moving the latter furnace in the direction of advance of the stock for treating the forward end of the stock.

14. The combination as set forth in claim 13, and means tending to hold said other furnace from movement in the direction of advance of the stock, whereby the stock may be drawn through the pressemmembers in said other furnace.

15. A tempering furnace having a chamber for receiving stock, presser members in said chamber and engageable with stock disposed therein, feeding means for advancing stock to the furnace, the feeding means and the furnace being relatively movable toward and from each other along the path of advance of the stock, means for effecting relative movement between the feeding means and the furnace so that stock may be rapidly introduced into the furnace whereby the forward end of such stock may be uniformly treated.

16. The combination as set forth in cla m 15, and means for moving the furnace with

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