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Publication numberUS1084897 A
Publication typeGrant
Publication dateJan 20, 1914
Filing dateSep 18, 1912
Priority dateSep 18, 1912
Publication numberUS 1084897 A, US 1084897A, US-A-1084897, US1084897 A, US1084897A
InventorsWilliam J Parkinson
Original AssigneePritchard Stamping Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Guard for machinery.
US 1084897 A
Abstract  available in
Images(1)
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Claims  available in
Description  (OCR text may contain errors)

W. J. PARKINSON. GUARD FOR MACHINERY. APPLICATION FILED SEPT. 18, 1912.

Patenm 11.20, 1914.

stratr zs WILLIAM J. ramrrnson, or B-QGH-ES IEB, unwyonn, assrc voa ro rarronann- STAMPING COMPANY, or nocnns'rna; navy roan, A GQBPQBA'EION or. new

YORK.

GUARD FOR MACHINERY.

Specification of Letters Patent.

Patented Jan. 20, 1914.

7 '0 all whom it may concern:

Be it known that I, WILLI M J. PARKIN- SON, a citizen of the United States, and resident of Rochester, in the county of Monr e a d tate of New or ha in certain new and useful Improvements in Guards for Machinery, of which the followh1g1 is a specification;

his invention relates to guards, such as are employed in connection with presses and other machines, to revent injury to the hand of an operator through accidental contact with the operating-instrumentalities or moving parts of such machines. In guards of thek'ind in question, especially as used in connection with presses, t has been common to employ a guard-member which is normally out of operative position, so as to afford unobstructed access to the dies or other instrumentalities ofthe machine, but which is so connected with the mechanism by which the machine is started and stopped as to be moved into operative position just before, or at the same time that, the machine is thrown into operation by means of u treadle or other manually-operable member. The p s nt invention rela to guard of this type, and the ob'ect of the invention 7 is to produce a guard 0' simple construction an re iable op n, an Pa i ular y to so arrange the mechanism by which the uard is actuated and the machine is controlled that the uard may be moved fully to operative posi ion before any movement is imparted to the clutch or other device by which the machine is thrown into operation, thus void ng th anger f op ra i mo ment of the machinebefore the guard has been bro ht lnto a osition in which it will absolu ely prevent the operators hands from being engaged by the'moving parts of the miwhine.

To the foregoing end the invention consists in the guard hereinafter described, asit is efined in the succeeding claims.

11 the ac omp ny ng drawings igur 1 is a side-elevation of a press rovide with a guard constructed in accor ance with the present invention; Fig. 2 is a rearrelevation, on a larger scale, of a portion of the guard-mechanism including the three rockne memw e; Fis- 3 is a ca median -we 0f t me dow in e 2; fig 4, ,5 one B are sideelevations. camel r 1 section, on the line X-X in Fig. 3, showing diflerentoperative positions of the guardmechanism.

The invention is illustrated as applied to a press of ordinary form, such as is employed in InctaLpunching and stamping operations, this ress having the usual vertically-movable head 1 and actuatingmechanism therefor including a drive-shaft This drive-shaft is thrown into and out of operation in the usual manner, by aclutch which may be of any ordinary or suitable form, and is not, therefore, illustrated. This clutch is thrown into and out of operation in the usual manner,by means of mechanism including a bell-crank lever 3 ivoted on the frame 7 of the machine, this liver being rocked clockwise, or to the right, from the illustrated position in order to throw the clutch into operation. The press is also provided in the usual manner with a manuallyoperable member. in the form of a treadle 4. which is depressed by the operator for the purpose of l'ln'owin the drivingmcchanisln into operation. his treadle is carried by a lever 5, which is pivoted to the frame at 6 and is held normally in raised position by a spring 38. The guard-proper comprises a horizontal bar 8 which extends transversely in front oi the head 1.. This bar is mounted in a lug 9 ad'ustably fixed upon a lever 10, which cxtcn s rearwardly and is arranged to swing about whorizontal stud ll projectin from the frame 7. When the machine at rest the guard-bar 8 is held in raised position, the lever 10 beiu provided with a counterweight 12 for th s purpose and being arrested in normal position by a sto -screw 13 threaded into 1). lug projecting iion the frame 7.

' In order to guard the hand of the operator from accidental engagement with the dies when the press is in operation it is necessary that the lever ll) be swung downwardly and the guard ha" 8 brought to the level of the table .26 ot the press before the clutch is operated to start the uu'vvmncul, of the n'css. and for this rmrposc the guard "mechanism is associated with the connections between the treadlelever 5 and the bell-crank lever 3 through which the clutch is actuated. The construction by which thisis oocouiplished is shown partlcularly in F gs. 2-6. The lever 10 is fixed in an arm consiituiiun a lever 3. g a j I Since the rocking-memberlG, through its connection with the treadle, constitutes part of'a roclringme'mber 14 journaled upon the stud 11. The rocking-member 14 is provided with a cylindrical hub or sleeve 15 -which constitutes a journal and support for another rocking-member 16. Themember 16 is also provided with an arm, to which is pivoted the upper end of a rod 1'7 connected, at its lower end, with the treadle-lever 5, sothat when the treadle is depressed the member 16 is rocked about the sleeve 15.

A washer 18 on the stud holds the members 14 and 16 against endwise movement there from. Still another rocking-member 19 is journaled on the stud, and has an arm WlllCh is connected, by a rod 20, with thebell-crank means by whichboth the guard-proper and the clutch are actuated, and since it is desirable that the guard be brought fully. into operative position before any movement is imparted to the clutch, it is necessary that after the guard has been so brought down the-member 16 may be further actuated, by continued movement of the treadle, to operate the clutch, while the guard remains in stationary position. Accordingly, yielding connections are employed between the guard and the rocking-member 16, to permit independent movement of the latter. A post 21 projecting from the member 16, and a pin bar 8 rests upon the top of the table 26, as

shown in Fig. 5. During this time the rocking-member 19 remains stationary, no movement .being. imparted to the clutch. In order that the clutch may be thrown into operation} at the proper time, however, a lug .27 projects from the rocking-member 19 in a position in which it may be engaged by the inner extremity of the lug 24 when the member- 16 has moved from the normal position of Fig. 4 to the position of Fig. 5. Accord-V ingly, after the guard has been depressed as just described the continued downward movement. of the treadle, through the engagement of the lugs 24 and 27, causes the member 19 to rock, thus pulling downwardly the rod 20 and swinging the bell-crank lever '3 so as to actuate the clutch and throw the driving-mechanism into operation. During this later part of the movement of the treadle the guard-proper and the member osses? 14 remain stationary, and the spring 23 yields to permit the. continued movement of the member 16. i i i It is important that in case the operators hand be in position to be engaged by the guard in its descent the operation of the clutch be positively prevented until the-hand has been withdrawn from such position. Accordingly, means are provided for posi-, tively interconnecting the members 16 and 14 under such circumstances, to interrupt the movement of the member 16 until the guard has been permitted to descend fully to operative position. For this purpose the. member 14 is provided with a lug 28 having an adjustable stop-screw 29 which is ada p'ted to engage the upper surface of the lug 24. The stop-screw is so adjusted that in the normal operation of the mechanism, when the guard has descended fully to operative position, the screw is not engaged by the lug 24 until the member 16 has been rocked throughout its entire range of movement and the clutch has been thrown into operation. As shown in Fig. 5, for example, it will be apparent that when the guard is in depressed position there is sufiicient space between the screw 29 and the lug .24 to permit further movement of the member 16,

and, as the lugs 24 and 27 are at this time case before the lug 27 and the member 19 have been moved far enough to throw the clutch into operation. The member 16 being thus arrested positively, the machine cannot be started until the operators hand has been withdrawn so as to permit the guard to descend fully.

In order that the operator may be pre vented from introducing his hand to a position of danger after the guard has descended, a screen or plate 30 is preferably fixed to the bar 8 so as to project upwardly therefrom and close the entire space between the table 26 and the head 1 of the press. The arrangement of the rocking-members 14 and 16 by which the latter is journaled upon the former, as described, not only renders the mechanism compact and rigid, but also reduces the friction of its operation, since the members 14 and 16 turn as one during the -movement is imparted to the clutch 'to throw the drivingmechanism into oporation. In guards previously employed this has not been the case, but movement has been imparted simultaneously to the clutch and to I the guard during the whole or a portion of the operative movement of the guard. Such an arrangement is, however, unreliable owing to the fact that the guard does not fully reach its operative position before movement is imparted to the clutch, so that as the result of wear upon the parts of the clutch-mechanism the clutch is liable to become operative before the full movement of the controlling-mechanism originally provided for, and, accordingly, guards constructed as just described do not constitute complete safeguards against the presence of the operators hand at the point of danger when the machine begins to operate.

-My invention is not limited to the embodiment thereof hereinbefore described and illustrated in the accompanying drawings, but may be embodied in various other forms within the nature of the invention as it is defined in the following claims.

I claim a 1. In combination with a press having a driving-clutch and a treadle; a first rockingmember having a bearing on a fixed part of the machine and connected with the treadle; a second rocking-member journaled coaxially with the first and connected with the clutch: a third rocking-member journaled coaxially with the first and second and car rying a guard adapted to swing into position in front of the operative instrumentalities oft-he ress; a spring connecting the first and third rocking-members to swing the guard into operative position during the first part of the movement of the treadle; cooperating abutments on the first and third rocking-meinbers. normally separated to provide lost-motion,but adapted to move the guard positively to operative position during the later part of the movement of the treadle; cooperating abutments on the first and second rocking-members normally separated to provide lost-motion but adapted to move the second rocking-member and throw the clutch into operation during the later part of the movement of the treadle; and means for raising the guard out of operative position when the treadle is in normal position and the clutch disengaged.

2. In combination with a press having a driving-clutch and a treadle; a first rocking member having a bearing on a fixed part of the machine and connected with the treadle; a second rocking-member journaled coaxially with the first and connected with the clutch; a third rocking-member journaled coaxially with the first and second and carrying a guard adapted to swing into position in front of the operative instrumentalities of the press; a spring connecting the first and third rocking-members to swlng the guard into operative position during the first part of the movement of the tread e; cooperating abutments on the first and third rockingmembers, normally separated to provide lostmotion, but adapted to move the guard positively to operative position during the later part bf the movement of the treadle; co6pcrating abutments on the first and second rocking-members, normally separated to provide lost-motion, but adapted to move the second rocking-member and throw the clutch into operation during the later part of the movement of the treadle; means for raising the guard out of operative position when the treadle is in normal position and the clutch disengaged; and a stud fixed in the frame and upon which the second and third rocking-members are mounted directly, the first rocking-member being mounted, and having a bearing, upon the third rockingmember concentric with the stud.

WILLIAM J. PARKINSON.

Witnesses D. Gunners, L. THON.

Copies 0! this patent may be obtained for flve cents each, by addressing the Commissioner of PatentI,- Washington, D. C.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2831371 *May 7, 1956Apr 22, 1958Guard IncShear guard
US4420071 *Sep 21, 1981Dec 13, 1983Yoshida Kogyo K.K.Safety device for machine having forceful reciprocation
US6131429 *Feb 11, 1999Oct 17, 2000Ward; James C.Safety device for press brake
Classifications
U.S. Classification192/134, 74/616
Cooperative ClassificationF16P3/04