US2584534A

US2584534A - Drop hammer safety device

Info

Publication number: US2584534A
Application number: US711093A
Authority: US
Inventors: George E Barnhardtson
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-11-20
Filing date: 1946-11-20
Publication date: 1952-02-05
Anticipated expiration: 1969-02-05

Description

Feb.5, 1952 Filed Nov. 20, 1946 G. E. BARNHARDTSON 5 Sheets-Sheet l "Ill INVENTOR.

5, 1952 G. E. BARNHARDTSON 2,584,534

DROP HAMMER SAFETY DEVICE Filed Nov. 20, 1946 1 3 Sheets-Sheet 2 1 A i {/5 L INVENTOR.

@Qzaaagy DROP HAMMER SAFETY DEVICE Filed Nov. 20, 1946 5 Sheets-Sheet 5 Patented Feb. 5, 1952 uNiTEo sTAT S PATENT bFFlCE DROP HAMMER, SAFETY DEVICE George E. Barnhardtson, North Providence, It. I. Application November 20, 1946, Serial No. 711,093

Claims. 01. 192-129) The present invention relates to drop hammer machines operated byhydraulic pressure, and has particular reference we safety device for use with pneumatic lift gravity drop hammers, power presses, foot presses and the like.

Theprincipal object of theinvention is to provide a pneumaticsafety' device which prevents inadvertent release of the hammer head, and in addition operates a guard for throwing ,out the handsof the operator before the hammer head descends.

. Another object of simple arrangement for a safety device which may be readily applied to existing installations of pneumatic drop hammers, power presses, foot presses and the like.

Still another object of the invention is to provide a safety device which is hydraulically operated in prior timed relation to the release of the hammer head, so that the safety provisions are operative until the hammer head is released.

, With the above and other objects and advantageous features in view, the invention consists of a novel arrangement of-parts more fully disclosed in the detailed description following, in conjunction with the accompanying drawings, and more specifically defined in the claims appended thereto.

In the drawings:

.Fig. 1 is a front elevation of a standarddrop hammer installation in which the novel safety device is incorporated, parts being broken away;

Fig. 2 is a side view of Fig. 1;

Fig. 31s a detail view showing the spiral controls for the hammer operation;

Fig. 4 is a detail section on the line 4-4 of Fig. 1, showing the safety parts in safety position; and

Fig. 5 is a view similarto Fig. 4, showing the safety parts in hammer release position.

It has been found desirable to provide a safety device for a drop hammer, which positively locks the hammer in raised position until both hands of the operator are away from the anvil and are engaged in pressing dual valve controls to re lease the hammer head, whereupon the safety lock is released and a hand guard sweep is simultaneously moved across the face of the anvil. To this end I provide a control mechanism which may be attached to a drop hammer or press of standard type to function in timed relation to the the anvil to slidably carry the drop head l5, and

a yoke I6 is mounted on the upper end of the columns l3, I4 to carry a pneumatic lift cylinder I! which is bolted to the central portion of the yoke and has a central lift rod l8 which is connected at its upper end to the cylinder piston, not shown, and at its lower end to the drop head l5.

the invention is to provide a The control of pressure air to andlfrom the lift cylinder 1'! is accomplished through a valve housing l9 which includes an operating control valve 20, and an inflow valve 2 Air under pressure is supplied to the valve housing I9 from a main pressure air conduit 22 through a reducing valve 23 and a main conduit 2%, and passes through the operating control valve 29 and the inflow valve 2| and through a passage in the yoke IE to the lift side of the piston in the lift cylinder l5. Air is exhausted from the cylinder ll through an exhaust passage in the yoke which leads through the operating control, valve 20 and an adjustable bleed valve 25 to atmosphere.

The operating control valve 20 is mechanically actuated by a rotatably mounted vertical rod 26, see Fig. 1, which has a spiral cam 21 secured at its lower portion with which a pin 28 at the lower end of the drop head l5 cooperates. The inflow valve 2| is mechanically controlled by a rotatably.

mounted vertical rod 29 which has a spiral cam 30 secured at its upper portion for cooperation with a pin 3| at the upper end of the drop head When the drop head 15 is in its up position the inflow valve 2| is shut to the fiow of pressure air, but a by-pass, not shown, in the valve housing, permits air under pressure to enter the lift cylinder and keep the drop head up. When the drop head drops the upper head pin 3| turns the cam 30 and the rod29 to set the inflow valve 2| in open position, whereby pressure air may enter the lift cylinder through the operating control valve 20 when the lower head pin 28 turns the,

cam 2! and the rod 26. The drop head is released when the control valve is opened to exhaust, as hereinafter explained, the speed of drop being controlled by the bleed valve 25, which may be manually set by turning a vertical control rod 32 by means of a handle 33.

The control valve is turned to exhaust position by a hydraulic trip 34 which is in a housing 35 at the right of the anvil, the pressure air for actuating the trip passing from the cylinderair supply through a conduit 35 which extends around the anvil, and has a connection 3'! leading into the housing 35; a manually operable shut-off valve 38 is mounted in the line and two spring pressed

hand valves

39, 40 are also in the line and are, adapted to be manually depressed through hinged plates 4 42, whereby both hands of. the operator must be applied to release the drop head.

Referring now to Figs. 4 and 5, a-safety cylinder itis mounted at one side onthe anvil and has a spring pressed plunger 44 which is lever connected to a hub 45 keyed to a rotatable vertical rod 46,. A look element 41 is keyed to the rod 46 and isadapted to position a lock finger 48 in the path of downward movement of the drop head to lock the drop head in its up position, the hub 45 having an extension 49 to which an anvil sweep 50 is connected The plunger is actuated by pressure air from a conduit 5| which passes through a valve housing 52 in which a reciprocable valve 53 slides, he valve having a slot 54 to selectively open an inlet passage 55 and an exhaust passage 56, the inlet passage receiving pressure air through a connection 51. The valve 53 has a hinged valve rod 58 which has a'slotted end 59, and a hub 60 is keyed to the control rod 29 and has an adjustable end bolt connection which extends through the slotted valve rod end 59 to obtain a predetermined timed operation of the valve 53 with respect to the movement of the control valve to exhaust position. WVhen the rod 29 is turned by the drop head pin ,3! on (its upstroke the valve 53 is moved to open the exhaust passage 56 and thus causes locking movement of the lock element 41. When the trip is actuated by manually pressing the valves 49, 40 to open position, the rod 29 turns, the valve 53 is opened to entry of pressure air which shifts the lock element 4'] out of the path of downward movement of the drop head and at the same time sweeps the anvil sweep 50 across the face of the anvil, and the control valve is simultaneously turned to exhaust, whereby the drop hammer drops, the lock element being mounted at .a distance from the drop head to provide sufiicient clearance between the drop head and the lock finger. When the drop head is lifted, the control rod moves to shift the valve 5s and the lock element moves to assume its normal lock position in the path of downward movement of the drop head.

The above described safety arrangement is thus simple in construction and effective in operation, and may be readily adapted to standard drop hammers and presses.

Although I have described a specific construc- .tional embodiment of my invention, it is obvious that changes in the size, shape, and arrangement,

of the parts may be made to suit different types and styles of drop hammers and presses, without departing from the spirit and the scope of the invention as defined in the appended claims.

I claim: I

1. A safety device for a drop hammer having an anvil, a drop head, and mechanism for lifting and for releasing the drop head, comprising a lock element normally positioned in the path .of downward movement of the drop head,

for preventing said downward movement and an anvil sweep adapted to move across the face of the anvil, and manually operative means for initiating downward movement of the .drop head for shifting the lock element out of the path of the drop head and for moving the anvil sweep across the face of the anvil, and means .operative upon lifting movement of the drop head for shifting the lock element back into the path of the drop head and for moving the anvil sweep back .to its original position.

,2, A safety device for a drop hammer having" an anvil, a drop head, and pressure actuated mechanism for lifting and for releasing the drop head, comprising a lock element normally Positioned in the path of downward movement of the drop head for preventing said downward movement, and manually operative means for initiating downward movement of the drop head for shifting the lock element out of the path of the drop head, and means operative upon lifting movement of the drop head for shifting the lock element back into the path of the ,drop head, said means including a cylinder having a pressure actuated piston and .mechanism connecting the piston to the lock element.

:3. A :safety' device forafidrop hammer having an anvil, a drop head, and a pressure actuated mechanism for lifting and for releasing the drop head, comprising a lock element normallypositioned in the path of downward movement of the drop head for preventing said downward movement and an anvil sweep adapted to move across the face of the anvil, and manually operative means for initiating downward movement of the drop head for shifting the lock element outof the path of the drop head and ,for moving the anvil sweep across the face of the anvil, and means operative upon lifting movement of the drop head for shifting the lock element back into the path of the drop head and for moving the anvil sweep back to its original position, said means including a cylinder having a pressure actuated piston and mechanism connecting the pistonto the lock element and the anvil sweep.

4. A safety device for a drop hammer having an anvil, a drop head, and pressure actuated mechanism for lifting and for releasing the drop head, comprising a lock element normally positioned in the path of downward movement of the drop head for preventing said downward movement, and manually operative means for initiating downward movement of the drop head for shifting the lock element out of the path of the drop head, and means operative upon liftingmovement of the drop head for shifting they look element back intothe path of the drop head, said means including a cylinderhaving a pressure actuated piston, and ,a control valve operated by the drop head, and mechanism 'connecting the piston to the lock element.

5. Asafety device for a .drop hammer having an anvil, a drop head, and a pressure actuated mechanism for lifting and for releasing thedrop head, mcomprising a lock element normally positioned in the path of downward movement of the drop head for preventing said downward movement and an anvil sweepadapted to move across the face of the anvil, and manually operative means for initiating downward movement of the drop head for shifting the lock element out of the path of the drop head and for moving the anvil sweep across the face of the anvil, and means operative upon lifting movement of the drop head for shifting the lock element back into the path of the drop head-and for moving the anvil sweep back to its original position, said means including a cylinder having a pressure actuated piston, a control valve operated by the drop head, and mechanism connecting the piston to the lock element and the anvil sweep.

. GEORGE E. 'BARNHARDTSON.

REFERENCES CITED The following-references are of record in the file of this patent:

UNITED STATES PATENTS Number Name .Date

1,082,685 Dyer Dec. 30, 1913 1,084,631 Hazel et a1. Jan. 20, 1914 1,18%,446 Hamilton May 23, 1916 1,196,764 Dicks Sept. 5, 1916 1,511,113 Doersam Oct. 7, 1924 1,722,506 Sahlin'; July 30, 1929 2,240,630 Stacy May 6, 1941 2,246,021 Sturm et a1. "is" June 1'7, 1941 2,339,214 Yanchenko Jan. 11, 1944 2,429,261 Ewaldson Oct. 21,1947'