US1998245A - Guard for power operated machines - Google Patents

Description

April 16,` 1935. A. LAUKHUFF 1,998,245

GUARD FOR POWER OPERATED MACHINES Filed May 4, 1933 2 Sheets-Sheet 1 INVENTOR.

April 16, 1935. A. LAUKHUFF ,1,998,245

I mmm)v FOR PwER OPERATE'D MACHINES Filed May 4, 1953 2 sheets-sheet 2 L. v f

@1% MMU-b Ml ATTORNEY;

Patented Apr. 16, 1935 GUARD" Foe POWER. oPuRAritnMACHINEs Alfred Laukhuff,"Milwaukee',- Wis., Yasitigi'ior to; Alfa Machine Company, Milwaukee, rWis.,l a r corporation 'of Wisconsin Application nay 41, y193s;Y serial N I invention'relates to guardsforfm'achines having power operated parts liable 'to inflict serious injury to the'operators' thereof. in the event members ofthe operators body are allowed to remain inthe path of movement of the power driven parts when the latter 'areactuated The invention is shown as applied to a power driven cutting machine but, of course,fis applicable with equal advantage to power driven presses or othery types o f machines.

YOnefof the objects of the presenty invention is to provide a guard which sweeps from the field of vaction of the power driven partsthe opera-V tors hands orA other Amembers of his body, when the power driven parts are actuated and .pre sents an effective barrieror guardv throughout the operation of. the power driven partsr'The action of the guardis so timed that it exerts its sweepingaction and is placed in guarding Aor operativepositi'on at Ythe moment of or just prior to actuation of the knife or other power driven part.

Another object. is to 'provide a guard of' this character and'which is simple and durablein construction, compactly V'and closely organized,

" reliable and eiicient in operation and .easy and comparativelyl inexpensive to `Inanufac ture and install.

Other objects and advantages 'reside certain novel features of the construction, arrangement and combination of partsr which will be hereinafter more fully describedl and particularly pointed out in the appended claims, reference being had to the accompanying drawings'gforming' 'a part of this specication, and in which:W f'

Figure 1 is a perspective view showing'a guard embodying the present invention applied to'` ar power actuated cutter; l

Figure 2 is a fragmentary view'in vertical sectiontaken in the plane of line 2-2 of Figure 1; Figure 3 is a fragmentary View of themachine shown in Figures l and 2 andlillustrating 'the same in front elevation; and f Figure 4 is a view similar to Figure 2 but showing a slight modification' in the operating` link` .through linkage designated generally' at 4 and shown in dotted lines in Figure '3, therebeing a clutch interposed between the power source and the movable knife,N which clutch maybe thrown in and out of engagement by 'actuation of'its clutch control' pjin 6. The cutting machine shown is of the type disclosed and claimed in my Patent No. 1,565,654, granted December 15,

192.5, ,and the clutch Vreferred to is of the type disclosed' my Patent February 5, 1929. I i r Y The clutchoperating p' is shifted to cause thefclutc'h to [be engaged yby means of a foot pedal I fixed on a shaft llsupported for rotation in` bars' I3 provided therefor on the frame I,` A crank arm I4 is fixed to the shaft' II and connects by means of aflink or Vconnecting rod I5 'withfa lever "I6 mounted for rotation" on a shaft `I1'al`so,' rnounted'on the frame I. The lever I6 isof the bell crank type and has an arm I8 pivotally y connected to'one end of la' thrust bar I9. The bar I 9 is notched as at 20 and is designatedto coact'with ltheclutch control pin'6 to actuate thisjpinand throw inthe clutch when theV foot Apedal luis depressed.` A spring '2I returns the foot-pedalv to its normal position in which the thrust bar I 3 is lowered and the clutch is disengaged; 'j

An enclosure designatedgenerally at 2 5 is pro-l videdjfor the movable knife 3 and its operating partsV and consists of transverse angles 26 supported upon the end structures 21 of the enclosure. The end'structures 2'IA arefsupported upon and extend upwardlyfromthe table 2a of the cutting machine.V A top plate 29 is fixed to these angles y25.` jAstationaryiguard 3D is secured to and depends fromV one'of the angles whereas a swingable .guardl Vis hinged or vpivotallysupeV ported as at 32 onthe'other; A second swingable guardlmeinber 33jis` provided and -is pivotally mounted yas at 34 on bracketlugs 35 secured to the frame of the machine. Asshown in the dravungs,` the` guard member 43 Ijjconsist's of a marginal` metal `frame, 36 to which a sheet of transparentjmaterial designated at 3l is fastened.

V The guard memberv 331 may consist of a metal plate carried'by an angle bar 38.V

' Linkage is provided between the* guard mem; bersi'3I and 33 to constrain them to corresponding movement, that is, to move simultaneously to guarding 'or operative position and'also to move simultaneously rto finoperative lposition. This linkage consists of. anarr'n' 40 secured to the'guard memberi33 and pivotally at its outer end lto vone ed of.` anni; 41; the other end of the iinkbeing pivoted to a bracket' lug 42 fastenedto the frame o f'the'guard membelji. Whenthe foot pedal I Il isjdepressed thelever Varm I8 swingsto raise the thrust bar I9`and throw in 'the clutchand the present invention .proposes to. utilize lthis motion of the 'lever'a'r'm I8 to swing the guard members 3I and;" 33 lt o closed position` before the shoulder 2lir of the'thrust bar engages the clutch operatingpin li'. For this purpose one end of a connectingrod' V5Il`iis pivoted-.to the outer endof the lever arm I8v adtlijpipvte E'ii'dfifthis con; necting rod is' pivotally connected "to 'on'earm'of the bell crank lever 5I fulcrumed on the frame of the machine. The other arm of this lever connects by means of a connecting rod or link 52 with the bracket 42 onA the guard member 3l. With this arrangementwhen the pedalA I .is delpressed the swinging movement of the lever arm I8 is transmitted through the connecting rod 50, bell crank lever and connecting rodl 52 to the guard 3l thereby swinging'the-guard 3| 'to the left, as viewed in Figure 2 and as indicated by the dotted arrow. This motionof the guard 3l, is transmitted to the guard 33 through the link 4I and arm 40 so that the guard 33 is raised or swung upwardly in the direction indicated by the dotted arrow. The guard 3l in swinging in the manner described willeectively sweep out of the path of movement "of the'knife the hand of the operator and will prevent'the operator from inserting his hand into the ,field of 'action of the knife. This action of the guard occurs 'every time the pedal is depressed and the guard remains in guarding position as long as thev` pedal is Vheld depressed.

In the embodiment of the invention shown in Figure 4, a slightly 'different linkage is employed between the guards in 'that a crank arm 50` is X'ed to the guard 33 and is' 'connected by'a link 5| to a' bracketlug or' arm '52 scuredto the guard 3l. The outer end of the'crank arm 5U' is provided with a crank pin 5 4 fitted in a slot 55 provided inaconnectingrod 56.' Aspring 51 has one end connected to' the'crankpin 54 and has its other end'connected to a cross pin 58 secured to the bar 56 whereby the spring 51 yieldably holds the pin 54 against one end ofthe slot 55. The connecting rod 56y is suitably'connected up with the. lever I8. With this arrangement, the mechanism can be designed to have the guard 3| swing to full guarding position'befo're the shoulderV 20 engages the clutch pinB.l Asv'the foot pedal is further depressed the clutchis thrown into engagement and this further motion ismade possible by the provision of the vlost motion connection constituted by the crank pin 54 and the slot 55. It will be understood that upon such further motion of the foot' p'edaltheba'r' 56 continues to move and it shiftsrelative tothe crank pin 54, the spring 51 yielding to permit of.' this relative movement. i v V While I have shown and described typicalembodiments of theinvention, itis' to be understood that the structures shown have' been selected merely for the purposes of Villustration and that various changes in the size, shape and arrangement of the parts may be made without departing from the spirit of the invention or the scope of the subjoinedclaims.

The invention claimedis: l. In a machine having a clutch rcontrolling its operation and afoot pedal for engaging `and disengaging the clutch, a. shiftable guard. onthe machine effective to enclose dangerous parts, and

means 'actuatedfrom the 'foot' pedal for shifting saidguard to enclosing position priorV .to the engagement of the clutch whereby said clutch is prevented from engaging if said guard "is not* in enclosing position.

2. In a machine having 'a clutch controlling its operation and a .control Idevice for engaging and disengaging the clutch, a shiftableenclosing guard on the machineand means actuated from said control device for kshifting theguard to' enclosing position upon manipulation of said control device prior to the vtime itengages said clutch.

3. In a cutter having a movable knife, a power drive for said knife, a clutch in said power drive and a control device for engaging and disengaging said clutch, a partial enclosure for said knife, a pair of separately hinged guard members effective to complete said enclosure, linkage interconnecting said member to constrain them to corresponding movement and means actuated by said control device for shifting said guard members to a position completing said enclosure when said control device is 'operated to engage said clutch.

4. In a cutterv having a movable knife, a power drivefor said knife, 'a clutch in said power drive and a control device for engaging and disengaging said clutch, an enclosure for said knife including a shiftable'guardmember acting when in one position to provide for access to the material being cut while effectinga guard 'for the knife and operating when shifting to sweep objects away from thepath of the knife and to providea barrier between the exteriorV of lthe enclosure and the path of the knife, and means actuated by said control device for shifting said guard member when said control' device is operated topengage the clutch and prior to the actuation of the knife. 5.' In a machine of the character described having an operating part, a vpower drive for said part, a clutchin said power drive and a control devicefor vengaging and disengaging said clutch, a shiftable guard for said operating part, said guard acting in one position to provide for access to said operating part and acting in another position to provide a'barrier preventing access to said part, and means for shifting the guard to the position in which it acts as a barrier when the control device is operated to engage the clutch and prior to actual engagement of the clutch.

6. In a machine having a clutch controlling its operation, a shiftable guard on said machine, a foot pedal, motion transmission mechanism betweensaid foot pedal and said guardand a lost motion connection between the motion transmission mechanism and the clutch whereby when the foot pedal is depressed the guard is first moved to position preventing access to a part to be guarded and the clutch is thereafter operated.

'7. In a machine having power actuated parts for operating upon the work, an enclosure for said parts', certain portions of saidV enclosure being swingable, and means for swinging said portions from'enclosure access position to enclosing position just prior to actuation of said parts.

8. In a machine having power actuated parts for voperating upon the work, an enclosure for said parts, an entrance for said enclosure comprising pivotally mounted door-like members, linkage interconnecting said members to constrain them to move ysimultaneously to open or closed position, a power drive for said parts, a device for throwing said power drive into operation and means 'connecting vsaid device with one of said "members

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