US2039964A - Safety guard mechanism for power driven presses and other machines - Google Patents

Description

May 5, 1936. 2,039,964 SAFETY GUARD-MECHANISM FOR POWER DRIVEN PRESSES AND OTHER MACHINES J. C. JUNKIN 5 Sheets-Sheeb 1 Wm. a

I c/bfi/i [ii/121 172 m w WW W Filed April 19, 1954 y 1936- J. c. JUNKIN 7 2,039,964

SAFETY GUARD MECHANISM FOR POWER DRIVEN PRESSES AND OTHER MACHINES Filed April 19, 1934 .5 Sheets-Sheet 2 5 Sheets-Sheet s May 5, 1936. J. c. JUNKIN SAFETY GUARD MECHANISM FOR POWER DRIVEN PRESSES AND OTHER MACHINES Filed April 19, 1934 eg m 5 Sheets-Sheet 4 E] YVU Mm J. c. JUNKIN SAFETY GUARD. MECHANISM FOR POWER DRIVEN PRESSES AND OTHER MACHINES Filed April 19, 1934 y 1936- J. c. JUNKIN 2,039,964 SAFETY GUARD MECHANISM FOR POWER DRIVEN PRESSES AND OTHER MACHINES Filed April 19., 1954 5 Sheets-Sheeb 5 Patented May 5, 1936 UNITED STATES awash PATENT OFFIQE SAFETY GUARD MECHANISM FOR POWER DRIVEN PRESSES AND OTHER MACHINES Application April 19, 1934, Serial No. 721,406

19 Claims.

..In..an application for Letters Patent of the United States filed by me May 23, 1932 and numbered, serially, 613,056, I have shown, described and. claimed a safety guard mechanism for 5 punching, stamping and embossing presses, and other power driven machines such as shears, etc., all of which, for the sake of brevity, are gener-ically, referred to as machines. My said safety; guardv mechanism comprises a locking 1 means having members co-operating with each other and with elements of the machine to which itis applied to prevent movement of the ram, plunger or corresponding part (hereinafter called .fworking member) of said machine to its workng position in the event that movement of the guarding member to its guarding position is obstructed, either by the hand of the operator or otherwise. My said locking mechanism is characterized, among other things, in that it includes 20 members :co-operating to cause the following phases of movement of the guarding member, and the working member of the machine to which the guard is applied when pressure is applied to the other operating lever (which is usually of a foot- 25 operated nature though it may be and sometimes ,is manually operated) of the machine, namely, the pressure .(l) releases the guarding member andpermits the latter to fall, by gravity, (2) at themoment said guarding member begins to fall 30 the operating lever is locked against movement until the guarding member has reached its final guarding position so that if the latter meets with an obstruction to its downward progress the operating. lever (shown as a pedal or treadle) remains in locked position and any pressure imposed thereon is not transmitted to the guarding member, orto any part of the machine whose operation by .the operating lever would permit move- .ment of :the working member; (3) when, and only when, .the guarding member has reached its final guarding .position the operating lever is released and by its downward movement becomes operative upon the clutch-trip pawl or dog of the machine, to release the mechanism which transmits 45 reciprocatory movement to the working member; (4) movement of the guarding member toward its non-guarding position commences immediately before .the working stroke of the work ing member, to thereby give free access to the die "and work operated on during the return stroke of the. working member, but this return movement of the guarding member does not commence until said working member has reached a position at .which the interposition of the guarding member between the same, and the hand of the operator is no longer required; and (5) the operating lever will be returned to its non-operating position and in its return movement will cause or permit the working member to be locked at the end of its non-working stroke until again released by repe- 5 tition of the foregoing phases of movement.

In the foregoing, and certain other respects, the instant invention is subordinate to certain claims of the aforesaid application for patent, a principal purpose of the present invention being to improve the locking mechanism shown, described and claimed in said application in certain respects by which its safety features will be extended to give absolute assurance against any repetition of the movement of the working meml5 ber of the machine to which it is applied unless and until the guarding member is in its fully guarding position, whether such repetition is brought about by accident, by Wear or by breakage or any other cause which unless guarded against would release the working member for its working stroke at a time which would endanger the operator.

The invention of the instant application for patent comprises certain novel arrangements and combinations of parts providing a mechanism applicable in principle to an infinite variety of power driven machines having working members of a nature such as to call for the guarding of the operator against injury from said members, an important purpose of the invention being to so co-or-dinate the elements of the guarding mechanism that the machine will be positively and unfailingly locked against working movement at all times except when the guard is in its fully guarding relation to the working members of the machines, respectively.

The accompanying drawings illustrate, and I will hereinafter describe, this guarding mechanism as applied to a stamping or punching press in which the guarding member and the locking members are positioned to work in vertical or substantially vertical direction, but I recognize the fact that in some machines said guarding member and locking members, and appurtenant parts, should be arranged to work horizontally, and I would have it understood, therefore, that the arrangement herein illustrated is exemplary only. Whatever changes are necessary to adapt the mechanism to work horizontally are within the purview of the skilled mechanic and hence need not be illustrated or described herein.

In said drawings, wherein like characters of reference denote corresponding parts in the several views:-

, tened relation to the adjacent end of the mem- Fig. l is an elevation of a punch or stamping press viewed from one side and showing the guarding member, proper, in its non-guarding position in full lines and in its fully guarding position in dot-and-dash outline;

Fig. 2 is a vertical section showing the clutch mechanism, the line of section being indicated at 22 on Fig. 1;

Fig. 3 is an elevation of the machine viewed from the side opposite that shown in Fig. 1 and shows the guarding member, proper in its fully guarding position in full lines and in its nonguarding position in dotted outline;

Fig. 4 is a detail View of the guard-timing means showing the position of the elements thereof when the guard is in either its fully guarding or in its non-guarding position;

Fig. 5 is a detail representation showing the course of travel of the eccentric or crank p0rtion C of the crank shaft in the movement of the working member of the press through its working stroke, the guarding member remaining stationary during said travel due to lost motion in the timing means;

Fig. 6 is a vertical section on the line 66 of Fig. 4, showing also the timing means in its fasber C of the crank shaft, said member being shown as broken off;

Fig. 7 is a view of the timing means as seen from the side opposite that shown in Fig. 4;

Figs. 8-12, inclusive, are detail views, with the face plate of the lock-casing removed to expose the locking and releasing members therein, and

shows said members in the various relative positions to which they are moved in the operation of the press and guarding member, proper-Fig. 8 showing the position of said members in the interims between successive operations of the press and when the guarding member is in its non-guarding position; Fig. 9 showing the position of said members when the operating lever, a pedal in this instance, has been depressed sufficiently to free the guarding member for its movement toward guarding position, Fig. 10 showing the relative positions of said members when the guarding member has reached its fully guarding position, Fig. 11 showing the position of said members when the clutch has been released to thereby permit movement of the working member of the press to its working position and Fig. 12 showing the relative positions of said members during the returning movement of the guarding member to non-guarding position and in the position in which the pedal is detached from the clutch release means;

Fig. 13 is a detail perspective view of the latching member viewed from the under or rear side thereof; and

Fig. 14 is a transverse section on the line l4- 14 of Fig. 11.

The illustrated press is of usual construction for punching and/or stamping operations, including a ram A whose upper end is connected by a pitman B with the eccentric or crank portion C of a crank shaft having members C and C which extend laterally in opposite directions from said eccentric portion C and are journalled in suitable bearings in the frame part D of the press. The crank or eccentric portion of said shaft,.together with the member C are shown in dotted outline in Fig. 3, as is also the pitman, and the member C of said shaft is shown in full lines, but broken off, in Fig. 2, and in dotted outline in Fig. 1.

On the member C of the crank shaft is a braking means E, as usual, and said member C also carries a timing means, hereinafter particularly described, whose function is to assure return movement of the guarding member in a predetermined timed relation with respect to the movements of the working member A, which as already stated, is carried by the eccentric portion C of the same crank shaft. Mounted on the other member C of the crank shaft is a clutch mechanism which, as shown in Fig. 2, comprises a flywheel F with clutch jaws ,f, a collar F keyed or otherwise fastened against movement on the member C a dog or pawl F having a spring I tending to move it into locking engagement with the clutch jaws f and a clutch release cam F arranged to control movement of the dog or pawl into and out of engagement with the clutch jaws and being itself under control of the operating lever G and locking mechanism hereinafter referred to. The cam F is providedwith a compression spring I which acts to force it'- yieldably to its clutch releasing position. The bearings for this member of the crank shaft are marked 0 It will be understood that, with the exception of the timing means whose function has been briefly set forth and which timing means will be hereinafter described in detail, the mechanism thus far described is substantially embodied commonly in presses for punching and/or stamping and/or embossing purposes, respectively, and also in machines for shearing, and in drop hammers and in other machines having means for effecting intermittent motion of the work performing member.

G designates the operating lever of the machine, here shown as a pedal or treadle, having a spring g for returning it to its initial position, defined by a stop 9, when relieved of the pressure which operated it, as usual in this class of machines. H designates the guarding member, proper.

The operating lever G has connection with the clutch release cam F and with the guarding member H, through mechanism including certain relatively movable interlocking and releasing members hereinafter described. These members are member is shown at I in Fig. 1. This casing may be arranged in any suitable position with relation to the operating lever and the parts actuated or controlled by said mechanism in effecting the phases of movement of the guarding member and working member hereinbefore referred to. In the particular press illustrated for exemplary purposes in the accompanying drawings, the casing and its contained interlocking and releasing members are mounted above one end of the. guarding member H, this being a convenient location therefor in this particular press.

The illustrated guarding member H is of substantially the same construction as that illustrated and described in my co-pending application (Se-r. No. 613,056) hereinbefore referred to. It is shown in a position whereby it may be moved gravitationally toward its guarding position and receives movement in the opposite direction from a transversely extending shaft J with which its side members have connection in any suitable way, either directly or indirectly according to the requirement of the particular machine to which the guarding mechanism is applied. It is here shown as having its opposite side arms, at points opposite its guarding end,

mounted in a casing, whose face fixed directly to the shaft, this being an appropriate means of connection in the particular machine illustrated in this application for exemplary purposes.

Reference has heretofore been made to a timing means operatively related to the guarding member. This timing means includes two complementary members, to wit, a loose disk K and a stop plate K relatively to which the loose disk is rotatively mounted, the stop plate being fixedlysecured to the contiguous end of the member C ofthe crank shaft, by bolts k or other appropriate fastening elements, and having a pin which projects laterally from its surface opposite the member C and upon which the loose disk is rotatably mounted. The loose disk K is provided with a pin k which projects laterally from opposite surfaces of the disk and the stop plate is provided with a cutaway portion k which forms a channel into which one end of said pin 70 projects. X designates a casing which is arranged between the stop plate K and the member C of the crank shaftand has a-circumferential flange which extends over the peripheral portions of said stop plate K and loose disk K and provides for the retention of grease or other appropriate lubricantwhich may be supplied to the channel 10 in any appropriate way.

'Upon the end of the pin 10 opposite the stop plate there is journaled the upper portion of a bearing L whose lower portion is hollow and-receives a rotatable member L which extends across the said lower portion-of the bearing at substantially right angles to the pin 10 "This member L is formed with an opening into which projects the upper end of a lifting rod L which is fixed in a set position therein by a fastening bolt Z whose head is exposed at the side of the bearing and whose inner end impinges upon the side of the lifting rod.

The mouth leading to the interior of said bearing and through which the lifting rod L extends into the member L is flared and said bearing provides a connector which, through its member L permits the lifting rod L to have back and forth swinging movement about the axis represented by the pin 76. This connector also enables said rod to be set into proper position with relation to the shaft J and also to the guarding member H to which its lower end is connected through the medium of a connector M. This connector M is carried by and has pivotal -movement relatively to, the corresponding side arm of the guarding member, the pivot of said connector being indicatedat m in Fig. 3.

The lower end of said lifting rod extends loosely through and protrudes from, the connector M and it is provided below the latter with an adjustable stop m which impinges against the connector M and enables the rod to lift the guarding member to non-guarding position. The cutaway portion of the stop plate K hereinbe-fore referred to is formed at its opposite ends to provide stops respectively marked a and b, to engage the pin k These stops are preferably concave in-order that the pin it will be effectively seated therein at the ends of the travel of the loose disk K relatively to the stop plate K Mention is here made of the facts that this travel of the loose disk is about the pin k and occurs in the present instance by gravity under the weight of the lifting rod L and bearing member L when the guard reaches its non-guarding position and that in said movement the-liftrecess 2.

ing rod passes loosely through the connector M so that the stop m is thereby spaced from the connector to permit the'guard to fall into guarding position-relatively to the rod at a predetermined time-in the movement of the operating lever G of the machine, all as will be hereinafter more fully explained.

Therelatively movable interlocking and releasing members hereinbefore referred to as beingmounted in a casing whose face member is shown at I in Fig. 1, are shown in Figs. 8-12, inclusive in various positions they occupy relatively to each other in operation. In these figures the members are shown in operative relation with a backing member I which in conjunction with said face member I forms a casing which receives said members and prevents interference therewith. Their ends protrude from said casing for connection, respectively, to the guarding member and the parts of the machine whose operations are controlled thereby when the operating lever is set in motion.

As here shown and as preferred the said locking and releasing mechanism includes three relatively slidable members respectively marked N, O and P, a latching member Q and a backing member R. The-members N, O and P have endwise relative sliding movement in the casing and the members Q and Ralso have endwise sliding movement in the casing but are arranged substantially at right angles with the members N, O and P. In addition to the foregoing members, this locking and releasing mechanism includes a floating lever S to which is pivoted, at s, the corresponding end of a member S One end of the member N has engagement throughout certain portions of its length with the corresponding edge of the member 0 and the other edge of said member 0 has engagement with the corresponding edge of the member P, for guidance purposes, the casing also being so formed that it will have a guiding function with relation to said members N, O and P and also with relation to the latch Q and backing member R, as in my application, serially numbered 613,056, hereinbefore referred to.

The latching member Q and the backing member R are respectively provided with springs Q and R and said backing member also has a friction-reducing roller R to engage the corresponding edge of the member N. The spring Q is arranged to press the latching member Q yieldably into operative relation with the members N and P and the spring R is arranged to hold the-roller R yieldably against the corresponding edge of the member N. It will be noticed that the backing member R extends partway over the face of the member Nand toward the end of said latching member.

The inner longitudinal side of the member N is provided near its upper end with a recess I and immediately below said recess with a deeper recess 2. These recesses are defined by a beveled shoulder 3 and a square shoulder 3 at opposite ends of the recess I and by said square shoulder 3 and a square shoulder 3 at opposite ends of the Said inner longitudinal side is also formed with a recess l arranged between shoulders 4 and 4 The inner longitudinal surfaces 5, 6 and l of this member (N) are in longitudinal alinement with each other and the surfaces 1 and F 8, which form inner walls of the recesses I and 4, respectivelyare substantially in alinement one with the other while the surface 9, which forms the inner wall of the recess 2, is arranged rearward of the lines of the walls I and 8. The outer wall or edge In, except for the indentation II, is plane throughout. This member (N) is also provided, near one of its ends with a stop I2 which projects laterally therefrom in opposite directions from its front and rear sides. Thus it is similar in all substantial respects to the corresponding member shown in my aforesaid application for patent, except that the recess 8 does not extend to the lower end of the member and has its opposite ends defined by shoulders l and 4 When operatively related to the machine it is connected to the guarding member H through the medium of an appropriate rod T one end of which is connected by a suitable connector T to the member N at the opening l3 when the locking and releasing mechanism is arranged above said guarding member, and at the opening l3 when it is arranged below said guarding member. The opposite end of said rod T is connected to the guarding member H by an appropriate connector T The member is of different construction in certain respects and has a different function from the corresponding member shown in my aforesaid application. It is provided along one side and intermediate its ends with a recess 14, one end of which is defined by a square shoulder l5 and the opposite end of which is defined by a beveled shoulder l6 which acts as a cam to free the floating lever S from the member P as hereinafter more fully explained. It is also provided at one end with a foot piece H which is suitably fixed thereto and, in practice, may be integral therewith. This foot piece projects laterally beyond the opposite sides of the member 0 and provides a flange one edge of which is received within the recess 4 in the member N and the opposite edge of which is received within a recess 18 which is formed in the contiguous longitudinal edge of the member P and is defined at one end by a shoulder H).

The other edge of the member P is formed, about midway of its length, with a recess 20 so formed as to provide a plane shoulder 2? at one of its ends a rearwardly beveled wall 22 which extends from said shoulder 2| to the inner wall 23 of the recess, and a plane shoulder 24 at the end of the recess opposite the shoulder 2| and inwardly offset from the latter shoulder. As thus far described this edge of the member is similar to the corresponding edge of the corresponding member shown in my aforesaid application for patent, but the shoulder 24 in this member P is comparatively short. Said edge is formed with an additional shoulder 25 which is space-d from the shoulder 24 and is shown as being oiTset therefrom. These shoulders 24 and 25 are connected by a wall 26-and the shoulder 25 is slightly concave to form a depression at its junction with said wall and the edge 28 extending from said shoulder 25 to the corresponding end of the member abuts against one edge of a guiding element 29 which forms a part of the backing member I The opposite edge of said guiding element is rounded as shown at 30 in order that it will not interfere with movements of the members S in the operations of the floating lever S and operating lever G.

The latching member Q, shown in detail in Fig. 13, is of the same construction as the corresponding member in my previous application hereinbefore referred to. Its undersurface is formed with a transverse opening Q and has a plane wall q which defines one end of the opening and the other end of said opening is defined in part by a plane shoulder q and by a beveled shoulder q The member P extends through the opening Q in the latching member and said opening enables the latching member to have horizontal endwise slidable movement relatively to the member P and the member P to have endwise vertical slidable movement relatively to said latching member. The beveled portion q of the latching member is arrange-d to be contacted by the beveled wall 22 of said member P and in the sliding movements of the latter member to cause said latching member to be retracted automatically in the downward movement of the member P. The upper surface of the latching member, adjacent the beveled portion q provides a stop q to co-operate with the shoulder 25 in preventing downward movement of the member P beyond the position shown in Fig. 9 when downward movement of the guarding member H to its fully guarding position is obstructed.

The member P when operatively related to the machine is connected to the clutch releasing cam F through the medium of a rod U one end of which is pivoted to said cam at d and the other end of which has a lost motion connection with the member P through the medium of a connector U having a pivot pin 32 loosely mounted in an opening 3| in the member P.

This connector U and also the connectors T and '1 intermediate the member N and the guarding member H, are each preferably of the same construction as the connector illustrated and described in my aforesaid application for Letters Patent, to which reference may be made for a. full understanding thereof. The nature of each of these connectors is such that quick and accurate adjustment, as well as pivotal movement of the rod U or the rod T, as the case may be, relatively to the member P or the member N and guarding member H is permitted without putting strain on the pivotal connection.

The floating lever S is pivoted at s to one end of a member S whose opposite end is connected to the operating lever G (as the treadle or pedal here shown), the connection including a rod V which is preferably made in sections having overlapping ends held in fixed relation with each other by an appropriate means 1) in order that the rod V may be adjusted in accord with the position of the frame part D which, as is common in this class of machines, is adjustable pivotally to various angles relatively to the base D of the press about the axis at d and is fixed in adjusted position by means indicated at d. Interposed in the connection between the operating lever G and member S is a spring 33 and a frame for said spring, the frame having side members 34 and a bottom member 34, the latter being provided With an opening through which the corresponding end of the rod V extends and the side members 34 having pivotal connection to the member S at 35. The upper end of the rod V extends through this spring and is arranged between the side members 34 and has its end provided above said spring with nuts 36 which are adjustably fixed thereon and form abutments for the corresponding end of the spring, the other abutment for said spring being provided by the bottom member 34 of the spring-frame. This spring permits the operating lever to be pressed to its extreme movement in one direction (toward the fioor in this instance) without putting overstrain on the locking mechanism when the movement of N the guarding member H to its fully guarding position is obstructed. The rod V is provided below the bottom member 34' of the spring-frame with a flange 3'! through which movement is transmitted to the floating lever, through the spring frame and nember S under control of the pedal spr 9- The endwise movable member is arranged between and with portions of its side edges in contact with, the corresponding edges of the members N and P and, moreover, is so positioned that its outer face is rearward of the plane of the ,outer faces of said. members N and P, as shown in. Fig. 14.

10 Thecorrelation of the members N, O, P and Q Wissuch that they mutually have a guiding function with respect one to another, and the face and ,backing members I and I of the casing are suit- .ably formed with relation to said members to ,assure'that there will be no wobbling tendency which would interfere with their accurate operation. In these respects, the present construction is similar to the construction shown and described in my previous application hereinbefore re- 'ferred to.

The inner end portion of the floating lever S is forked .to provide a channel through which the -en'dwise movable member'P extends and the opv posing walls' (31 and 31) of said channel are so arranged that they guide said member in the travel of the latter between the same. The forked end of said-floating lever is provided with a pin :38 which is normally seated in the depression 25 inthe member P and the free extremity of the inner wall 31 of said forked end portion is beveled, as shown at 39, and is so arranged that it will ;be contacted by the beveled shoulder IS on the mem- ;ber O in the upward movement of the latter member and will receivepressurefrom said beveled .35 shoulder acting to move thepin 38 out of the depression25 and to force the floating lever away from the member O and out of engagement with the member P. The member P is thus freed and permitted to be raised into locked position with ,40 respect to the latching member Q. 40 designates a spring which is arranged'within the lever and has one of its ends bearing'against the inner end of a plunger-4| whose outer end engages-a wall or member 42 of the casing, which wall or member 45 acts as astop to cause said spring to be placed undertension in the endwise outward movement of the lever. '-It will be apparent that when the pin 38 has been disengaged" from the depression 25 it will be pressed by the spring against the edge *Of the member P in the movement of the latter toits locking position relatively to the latching member Q and that in the reverse movement of tsaidmember P the spring will cause the pin to 1 snap into said depression.

The'free edge of the wa1l3'l of the forked end rportion of. the. floating .lever S is shown as being :beveled similarly to the corresponding part of the W3}11.31, but this is merely forconvenience in manufacturing the lever, it being evident that this :free edge of the wall 31' has no function in forc- :.ing the leverirearward when the corresponding surfaces of members N,;O andRhave the relationship hereinbefore-set forth: it being the free extremity of the wall 31 Whichacts in this respect by contact therewith of the beveled shoulder I6. --When5the machineis idle, as in the interim between successive work performing operations, the parts of the locking mechanism are in the relative positions shown in Fig. 8 and the guarding member, ram, latch releasing cam, etc. are

jin the positions shown in Fig. 1 and the timing :means is in the position shown in Fig. 4 with a ,liftin rod in the position shown in Fig. 3. In

3; the guarding member isshown in nonguarding; position in dot-,and-dash outline and it from the shoulder 3 .5 floating lever S and pin 38.

should be noted that the connector M is in the raised position and spaced-from the stop m on the lifting rod, the lifting rod being in-the position shown in dotted outline inFig. 3.

Upon reference to Fig. 8, it will be noticed that the latching end of the latching member Q ex- -tends into the opening 2in member N and has its upper surface in engagement with the shoulder 3 and thereby serves to hold said member N against movement in a downward direction. The lower surface of said latching member is spaced The foot piece I! ofthe memberO rests upon the shoulder 4 near the lower end of member N and its beveled shoulder 13 is near but out of contact with the beveled surface'39 of the floating lever. The shoulder 15 of this member 0 is above and spaced from the upper surface of the latching memberand the shoulder-2l of the member P is also above and spaced from the upper surface of said latching member. "The beveled wall-22 ofthis' member is in contact withthe bevelled portion 11 of the latching member and the lower surface of said latching member is spaced considerably from the shoulder'24. The pin 38 of the floating lever is within'the concave 25 of leverP. Asshow-n in dotted outline in'Fig. 8 the pin 32 forming a pivotal element of the connector U by which the rod U is connected to the upper end of the member P isarranged in the lowerend of the elongated opening 3|.

With the parts in this position theoperation is asfollows: When pressure is-applied to the outer end of the operating lever G downward movement is transmitted to the member 1? through the rod V, spring 33, spring casing 34, member As the result of this downward movement of the member P the beveled wall 22 thereof 'acts upon the beveled portion (1 of the latching member Q to retract the latching end of the latter from the opening 2 in the member N, thereby freeing said member N and permitting the guarding member H to'drop by gravity. The member 0 also drops by gravity with said guarding member, since its foot I! is now'freedfrom the shoulder 4 by which it was supported.

The elements are now in the position shown in Fig. 9, attention being called to the fact that the shoulder 21- is now in contact with the upper surface of the latching member Q. It will be understood that this movement was not transmitted to the rod U because of the lost motion connection between said rod and the member P. I-Ience the clutch release mechanism has not been affected and the working member A of the press is still held against movement toward working position.

If the movement of the guard to its fully guarding position is obstructed the elements will-remain in the position shown in Fig.- 9. In this position the member P is locked against further down- Ward movement by reason of the-engagement of shoulder2l with the upper-edge 0f the latching member, the working member A of the press hence remaining locked against movement to its wgrking position. If, on the other hand, there is no obstruction to the movement of the guard- .ing member to its fully guarding position the member N will continue to move downward and its shoulder 3 will act upon the corresponding edge of the latching member Q to force the latter to further retracted position, shown in Fig. 10, thereby freeing the upper edge of said latching member from the shoulder 2| and permitting to the position shown-in Fig. 11. By this movement of the member P the rod U is moved downward thereby acting upon the clutch release cam F which by its action upon the dog or pawl F operatesto engage the clutch, thereby permitting movement of the working member. It will be c1ear,however, that this movement of the working member does not commence until and unless the guard is in its fully guarding position.

The parts are now in the position shown in Fig. 11, with the guarding member H in the position shown in Fig. 3. This condition continues until the working member has almost completed its working stroke, at which time the guarding member commences its return movement to its non-guarding position, the beginning of this return movement being accurately timed with respect to the movement of the working member of the press, through the timing means hereinbefore referred to, said timing means operating as follows:

During the working stroke of the working member A the stop plate K is rotated by its connection to the member C of the crank shaft and its stop member 22 is thereby brought into contact with the corresponding end of the pin k which in turn rotates the loose disk K, thereby raising the lifting rod until its stop m comes into contact with the connector M on the guarding member and by its further upward movement raising the guarding member to the non-guarding position. When the guarding member has reached its non-guarding position the loose disk is permitted to rotate by gravity, under the weight of the bearing L and rod L and said rod L is dropped relatively to the guarding member H to the position shown in Fig. 3. Through the described movement of the timing means with relation to the guard, the shaft J is rotated, thereby communicating return motion to the ;member N, through the rod T. In its return movement to its initial position the rod N acts on the foot I! of member 0 and raises said member and said foot acts to raise the member P in a timed relation determined by the spacing of the upper edge of said foot from the shoulder I9 of said member P. Return movement of member O to its initial position causes it also to move the floating lever outwardly by the engagement of its beveled shoulder I6 with the beveled end 39 of said lever, thereby disengaging the pin 38 from the member P, this position of the parts being shown in Fig. 2. I

This disengagement of the pin 38 fromthe member P occurs shortly after the foot I! has come into engagement with the shoulder i 9, the delayed movement of member P with reference to members N and 0 being necessitated by the relative lengths of travel of the members N, O and P.

Member P being now disengaged from the floating lever S, the pedal is released from its operating connection with the operating mechanism of the machine. The pedal remains in this uncoupled Condition, in which it is inoperative with relation to the machine, until foot pressure has been removed from the pedal and the latter has again been returned to its coupled position by the spring g. However, it will be seen that unless the guarding member has returned to its fully guarding position the press cannot again be put in motion and, in short, cannot repeat its operation accidentally.

and the member P is thereby restrained from movement beyond that shown in Fig. 9, downward movement of the pedal G under pressure of the foot of the operator may be continued without transmitting movement to the member P,

the compressive action of .the spring absorbing this further movement of the pedal. 7

At the end of the initial movement of the member P, as a result of which the guarding member H dropped toward its guarding position, the clutch release cam F is moved to thereby release thedog or pawl F which being thus freed is moved into locking engagement with the clutch jaws F by its spring F, as previously explained. If the movement of the guarding member to its fully guarding position is unobstructed the working member A may now commence its working stroke. 7 At this time, and until the working member has nearly completed its working stroke, the guarding member is stationary. During this 'referred to part of the working stroke of the work: ing member the timing member K is rotating while the member K remains stationary. This condition obtains until, by reason of the relative movement of said members K and K, the stop a at the end of the channel k in member K is brought into contact with the pin k carried by member K. Further rotation of the crank shaft causes members K and K to rotate unitar-. V ily, thereby communicating return movement of 1 the guarding member to its guarding position. In the initial part of this movement, the portion of the timing means engaged with the rod L is passing around the lower center of its course of travel and hence, slow return movement is transmitted to the guarding member. Further along in the stroke the movement of the guarding member is accelerated since the movement communicated to the pin k is now in an upward direction. This accelerated movement of the rod L transmits like accelerated movement to the guarding member and begins at approximately the beginning of the return movement of the working member'A to its initial position;

As previously explained, the guarding member in its return movement transmits corresponding movement to the member N of the locking mechanism through the shaft J and, through the intermediate member 0, the member P is raised, thereby acting upon. the clutch release cam F and holding it in a position in which it becomes effective upon the'pawl or dog F to thereby release the members of the clutch from their interlocked engagement with each other when the working member has completed its return stroke. It will be understood that when the members N and P have thus been raised they are automatically locked in their said position, through the action of the latching member Q and being thus locked the clutch release cam F is also looked against any movement, arising from any cause whatsoever, which would render it inefiective in stopping movement of the press at the moment the working member A has completed its non-working stroke and thereby brought the pawl or release dog F into engagement with the clutch release cam and cause the latter to release said pawl or dog from the jaws 1. V p

The, clutch members are held in their disengaged relation with each other by the clutch release cam until the latter has been intentionally moved by pressure applied to the operating lever G and until said pressure is'efiective with respect to the rodV, member P and rod' U. In this connection, it will be remembered that pressure applied to the operating lever is ineffective upon the clutch release cam unless and until the guarding member is in its fully guarding position. It will also be remembered that at an early stage in the return movement of said guarding member to its non-guarding position the operating lever Was disconnected from the mem- -ber P and that pressure applied to it from any cause is not transmitted to said member P until '-after the clutch release cam has been moved v with the member P when the latter has reached operated reciprocatory working member, .operating lever and control connections between the operating lever and the working member: the said safety guard mechanism comprising a its elevated position. This reconnection of the operating lever with the member P hence does not take place until the clutch release cam has been moved to and locked in its clutch releasing position thereby preventing more than one complete reciprocation of the working member for each depression of the operating lever. In other words, the correlation of the operating lever,

guarding member, clutch release cam and the connections between said lever and cam is such that the working member must have completed its non-working stroke and the clutch release cam must have released the clutch dog or pawl from the clutch jaws before any pressure applied to the lever will be again effective upon said clutch release cam, so that unintentional repeating of the working stroke of the working member is positively prevented under all conditions.

Having thus described the invention what I believe to be new and desire to secure by Letters Patent and what I therefore claim, is:

l. A safety guard mechanism applicable to a powerdriven machine having an intermittently movable guarding member and means connected .to said. guarding member and arranged to be included in the control connections between the operating lever and working member, said means including a detachable member adapted for connection to the operating lever and operative under control of the guarding member to disconnect said operating lever from the control connections during the return movement of the guarding member to its nonguarding position.

2. A safety guard mechanism applicable to a power driven machine having an intermittently operated reciprocatory working member, an perating lever and control connections between the operating lever and the working member: the said safety guard mechanism comprising a movable guarding member and means adapted to be,controlled by the operating lever for holding the guarding member releasably in its non- .guarding position and the working member releasably in its non-Working position, said means including a series of members having relative movement one to the other, one of said members ating lever and said working member and still another being adapted for connection to the operating lever, said means also including a member which forms a detachable connection between the second mentioned and last mentioned members and is operative under control of the guarding member to release the operating lever from the control connections during the return movement of the guarding member to non-guarding position, when the safety guard mechanism is applied to the machine.

3. A safety guard mechanism applicable to a power driven machine having an intermittently operative reciprocatory working member, an operating lever and control connections between the" operating lever and the working member: the said safety guard mechanism comprising a movable guarding member and means adapted to be controlled by the operating lever for holding the guarding member releasably in its non-guarding position and the working member releasably in its non-working position, said means including a plurality of relatively movable members having an interlocking relationship one with another, one of said members being adapted for connection to the guarding member and another being adapted to form an element of the control connection between the operating lever and said working member, and also including a member adapted for connection to the operating lever of the machine anda detachable connection between the last mentioned member and the member second mentioned, operative under control of the guarding member to release the operating lever from the control connections during the return movement of the guarding member to its non-guarding position, when the safety guard mechanism is applied to the machine.

4. A safety guard mechanism according} to claim 2, in which the member which forms a tachable connection between the second mentioned and last mentioned members is pivoted to the upper end of said last mentioned member and is spring-pressed toward said second mentioned member and is provided with a projection,@

mentioned members is pivoted to the upper end? of said last mentioned member and is springpressed toward said second mentioned member and is provided with a projection, and with a beveled free end to be slidably engaged by the beveled wall of said additional member, and said second mentioned member has an open-sided recess to receive said projection and from which the projection is raised and the member forced outwardly by the beveled wall of the additional memher.

6. A safety guard mechanism for a power driven machine having an intermittently operated reciprocatory working member, an operating lever and control connections between the operating lever and the working member; said mechanism comprising a movable guarding member, a first member, having connection with the guarding member, a second member, detachable means to connect the second member with the operating lever,

said second member and detachable connection Operable upon initial movement of the second member to release the first member to thereby permit the guarding member to move toward its guarding position and to lock the second member against further movement it movement of the guarding member to its guarding position is obstructed, means for returning the guarding memher to its non-guarding position and means operable upon said detachable means to cause the lat er to be disconnected from the second member while the guarding member is returning to its nonguarding position.

'I. In a power operated machine having a movable working member, driving means, an operating lever and control connections for effecting intermittent operation of said working member by said driving means: a safety guard mechanism comprising a guarding member mounted to have movement to and from guarding position with respect to said-working member and means, including relatively movable members operatively related to said control connections, and to the operating lever and guarding means, and operative to successively release the guarding member for movement toward guarding position, lock said control means against operative movement if movement of the guarding member to'its completely guarding position is obstructed and permit the guarding member to continue its movement to its fully guarding position if there is no obstruction to said movement, said means including a detachably mounted member having connection with the operating lever, andmeans for detaching said member to thereby disconnect the operating lever, in the return movement of the guarding member to itsnon-guarding position,

' thefmachine also having means for effecting said return of the guarding member.

8. A power operated machine according to claim '7, in which the control connections include a clutch release cam which is positively held in locked position when the operating lever is disconnected or when the guarding member is in unguarding position, whereby unintentional repeating of the movement of the working member is positively prevented.

9. In a power operated machine having a movable working member, driving means, an operating lever and control connections for effecting intermittent operation of said working member from said driving means, said control connections having provision for lost motion and including a first member and a. second member, the second member being connected to the operating lever and provided with means forming a detachable connection between it and the first member, a guarding member mounted to have movement to and from guarding position with respect to said working member, a member having connection with the guarding member and operative under control of the first member to release the guarding member for movement to its guarding position 'in the initial part of the movement of said first 10. In a power driven machine, the combination of a driving shaft, a working member, clutch members interposed between the driving shaft and working member, a clutch release member,

a guarding member, an operating lever and control connections between said operating lever and clutch releasing member and guarding member, and also between the guarding member and the driving shaft: said connections including elementary parts which cooperate, upon application of pressure to the operating lever, to permit the guarding member to move to its guarding position and to move the clutch releasing member into clutch releasing position and cause the working member to be clutched to the driving shaft, said guarding member being arranged to release its fully guarding position before the working stroke of the working member commences, and the return connection to said guarding member operating to return the latter to its non-guarding position before the return stroke of the working member is completed, the connections be-' tween the guarding member and the operating lever operating to cause the operating lever to be operatively disconnected from the clutch releasing member and'the latter to be, moved to and ;locked in clutch releasing position before the operating lever is again operatively connected to said clutch releasing member.

11. A power driven machine according to claim in which the return connections between the guarding member and the driving shaft are arranged'to cause return movement of the guard.- ing member to be initiated before the working member has fully completed its working stroke;

and is initially slow and-then more rapid to its fully non-guarding position.

12. A power driven machine according to claim 10 in which the'connection between the operating lever and the clutch releasing member includes tently operated reciprocatory working member, a' guarding 'member movable gravitationally into guarding position with respect to said working member, and'means, including a member having movement relatively to the guarding member in one direction and operatively connectible to said guarding member for moving the same in the other direction, both in a timed relation with respect to the movements of the reciprocatory working member.

14. In a power driven machine, a shaft having an eccentric portion and a bearing portion, a reciprocatory working member carried by the eccentric portion of said shaft, a guarding member and means for controlling movement of the guarding member into and out of guarding position with respect to the working member, including a member operative to move the guarding member in one direction and a lost motion connection between said guarding member and the bearing portion of the shaft, arranged to permit the guarding member to move gravitationally to its guarding position in advance of the working stroke of the working member and to commence its movement to its non-guarding position in advance of the return movement of the working member to its initial position.

15. In a power driven machine, an intermittently operated reciprocatory working member, a

guarding member movable into and out of guard ing position with respect to said working member, a member for moving the guarding member in one direction and a lost motion connection between the guard moving member and the working member, arranged to permit the guarding member to move gravitationally to its guarding position in advance of the Working stroke of the working member and to commence its movement to its non-guarding position in advance of the return movement of the working member to its initial position.

16. In a power driven machine, an intermittently operated reciprocatory working member and power shaft for the same, a movable guarding member, and means for automatically controlling movement of the guarding member into and out of guarding position at predetermined times with respect to the movements of the working member, said means comprising a pair of complementary members automatically connectible to each other for unitary movement and disconnectible from each other for relative movement, one of said members being mounted to have movement throughout movement with and of the power shaft of the working member and the other having connection with the guarding member.

17. In a power driven machine, an intermittently operated reciprocatory working member and power shaft for the same, a movable guarding member, and means for automatically controlling movement of the guarding member into and out of guarding position at predetermined times with respect to the movements of the working member, said means comprising a pair of complementary rotatable members, one of which is formed with a channel and is movable with and throughout movement of the power shaft of the working member and the other of which is provided with a projection which extends into said channel, said channel and projection 00- acting to permit relative movement of the members throughout a part of a complete rotation of one of the same and to cause unitary movement thereof throughout the remaining part of said rotation.

18. In a power driven machine, a shaft having an eccentric portion and a bearing portion, a reciprocatory working member carried by the eccentric portion of said shaft, a guarding member and means for controlling movement of the guarding member into and out of guarding position with respect to the work performing member, including a member having a slidable connection with the guarding member in one direction of movement of the latter and operatively connectible to said guarding member for moving the same in the other direction, and a lost motion connection between said guard-moving member and shaft, comprising a complementary pair of members automatically connectible from each other for relative movement, one of said members being connected to the bearing portion of the shaft and the other having connection with the guard-moving member.

19, In a power driven machine, a shaft havingv an eccentric portion and a bearing portion, a reciprocatory working member carried by the eccentric portion of said shaft, a guarding member and means for controlling movement of the guarding member into and out of guarding position with respect to the work performing member, including a guard-moving member having a slidable connection with the guarding member in one direction of movement of the latter and operatively connectible to said guarding member for moving the same in the other direction, and a lost motion connection between said guard-moving member and the bearing portion of the shaft, comprising a complementary pair of rotatable members one of which is attached to the bearing portion of the shaft and has a channel which extends partway around the same and the other of which is provided with a projection which extends into said channel and has connection with the corresponding end of the guard-moving member, one end of said channel forming a stop which is engageable by said projection at the end of relative rotary movements of the members and said stop and projection being relatively arranged to permit relative rotation of the members and to cause unitary rotation thereof, during successive periods in the reciprocatory movements of the work performing member.

JOHN C. JUNKIN.

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