US2544682A

US2544682A - Latch

Info

Publication number: US2544682A
Application number: US632433A
Authority: US
Inventors: Walter A Hilgeman
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-12-03
Filing date: 1945-12-03
Publication date: 1951-03-13
Anticipated expiration: 1968-03-13

Description

March 13, 1951 w. A. HILGEMAN LATCH Filed Dec. 3, 1945 2 Sheets-Sheet 1 FIG. 4

FIG. 3

INVENTOR. MMU/5e Hm GUM/V BYwcwb Ma/vvd,

HTTOIEA/Eys March 13, 1951 w. A. HlLGrsMAN LATCH 2 Sheets-Sheet 2 Filed Dec. 3, 1945 FIG. 5

N .A MMMS TE.Y MG E VM N mim M W L MM Y B Patented Mar. 13, 1951 UNITED STATES PATENT oFFIci:

LATCH' Walter-A. Hilgeman, Fairview, I lpl.

Applica-tion December 3, 1945, Serial No. 632,433

(Cl- 29g-11.98)

8 Claimsl This invention relates to. a latch for use in connection with doorsfin. which a load presses; against. the door putting weightv on the latch so. that it must be released against the pressure of the load.. Morev specifically, it relates to a latch for use on the dipper-.of a power driven shovel. of the type which dumps through the back;

The` conventionalA type of= power driven shovel. has a dipper with a door in the back for dumping, the door being held` shut by a latch. The conventional latch in use on all such clippers comprises a latch-loarwhch-` moves in a vertical di. `recton more or less parallel to the back` of the clipper door and onev end: of which is inserted into. a slot in the dipper 110er-, The dipper is dumped by drawing the latch toward the top of' the door and out of the. slot. by meansof a motor-powered winch. Since the dipper is dumped through the back, it is apparent that theentire weight of the load rests on the latch when it is in dumping position. Therefore, in order to withdraw the bar, it must be pulled upward against the irictional pressure imposed by the loadf pressing it against the latch-bar slot.

In one broad embodiment, my invention comprises a latch comprising a slotted sill, a latch bolty or bar, means for pivotally mounting the` latch-.bar on a door so as to engage said slotted sill, the pivotpoint being intermediate the lengthl of said bar, trip. means pivotally mounted on the. door adjacent to but. spaced from the bar, means urging said trip means intoengagement with. one end of said barto prevent it from pivoting when in latching position, and means for pivoting the trip means toI permit said latch-bar to. pivot.

In another embodiment, the invention com. prises a latch-.bar pivoted. intermediate its length and mountedV for partial pivotal motion on the back of a dipper door, tripping means including a spring engageable withgone end ofsaidbar to prevent pivoting thereof when in latching position, and means associated with said. tripping means to release it: whereby said bar may pivot.

In a. specific. embodiment, `the invention come, prises` ar latch useful for example on a power f driven clipper, said latch comprising Va latch-bar ci engageable with a latch-bar-slot associated with `a' sill of clipper, said'bar being pivotal interme. diate its length and-pivotally mounted on a dipper A``door, the lower and upperends -ot saidlatch-bar being curved arcuately inwardly toward the dip. per door to form'bearing surfaces to. aid in the .opening and closing of' thelatch, a. trip, pivotally "mountedion the. dipper door adiaeentsaid. latchbar,said trip comprising a spring retaining mem-N ber,v aspringY urging one end of the trip againstl the latch-bar to prevent pivotal motion of the latch-har when in latching position, and to re-.. sist return of the latch-bar .to latching posi-.1. tion after the latch is released,` means to pivot`v said trip to release the latch-bar and permit it to be pivoted and thereby disengaged from the slot due to the Weightofthe, load within the, dipper.

The device has the advantage that the latch is as firmly held in latched position as with the conventional sliding bolt type latch, but that it can be tripped by the application of a relatively slight pull, since the release or tripnmechanism does not, have to. overcome the sliding irictional pressure of the loaded latch,l butA merely the pres.- sure necessary to hold the latch bar in position so it cannot pivot. Because of the lever prin. ciple used in my invention, the power necessary to trip. the latchl is 1essthantne weight thereof. The conventional latch-barmay weigh several hundred pounds in thev large machines, and requires a; substar-i-tial motor tov operate it` My. latch can be operated with a fractional horsepower motor.

With conventional latches the time lost in re.-,. pairs andi the like may amount to several hours. a week. This time is largely saved with my latch.

One difficulty experienced with conventional latches is in plugging of the latch-bar slot with rocks or dirt. Oftenthis must be cleared man-V ually, resulting in lost time. Due to the construction of my latch, the latch bar exerts aV prying action as it enters the slot, thereby clear-4 ing it of impediments and saving time. My latch automatically closes and engages when the door slams shut the first time which is not always the case with the conventional latch. This alsolv is time consuming. Since the larger machines,y e.. g. ear-th stripping shovels of 2.0-35 cubic yardsA capacity,-` are rated at several hundred dollars:

per hour, every improvement in efficiency rep-` resents a material iinancialsaving.

Other advantages will become apparent from the fel-lowing description.

'Ehe inyentienis illustrated. in the. aeeempapreA ins drawings.-

Fsure lillustrates one embodiment of the in: ventien shop/nin perspective and; partly in See: tion from the beek, e.. facing the. @10er-4 Fislire 2; is a plan view of the latch with the protecting cap removed. Figure 3 is a side view partlyv in Section takenthroushlne V'3a-.3 spewing the trip in latehins positilrr! Figures is. e side. vieweine.

ilar to Figure 3 but showing the latch released. Figure 5 is a view from the top with the cap in place. Figure 6 is a perspective view partly in section of a detail of the trip mechanism. Figure "I is a detail showing one type of shaft assembly for supporting the latch-bar.

Referring to the drawings, a section of a clipper door of a power driven shovel is generally indicated at I0. In the conventional type of clipper, a stiiener II may extend around the edge of the door to prevent its buckling under the enormous weights which it must sustain. The bottom of the dipper is indicated at I2. Associated with the bottom of the clipper (the sill) and extending parallel thereto but projecting beyond the general contour of the bottom is a sill member I3 containing a latch-bar slot I4. The edge of the slot is approximately flush with the dipper door when it is closed. This is so that when the latch-bar is in position and the door is latched, it will be held firmly in place without substantial vibration. The construction of the sill and slot may vary depending on the device. For example, the slot may be in the sill itself.

Attached to the bottom I2 of the dipper is a stop I5 which is approximately the width of the latchbar and extends above the bottom of the clipper or the sill. The face of the stop is slightly curved to conform to the curved lower face of the-latch bar 28 so as to guide it into the latching position as the door swings shut. It will be noted thatv this action exerts a prying effect on any material that may stick in the Slot, thereby clearing it' and assuring the latching of theY door." The` weight of the door aids in this, while in conventional latches the only effect is obtained by the weight of the latch-bar. This stop may be built u'p approximately the width of the latch-bar and then tapered toward the front of the dipper away from the sill to form a beaver tail which strengthens the stop. An opening I6 is cut in the door to permit it to pass over the stop I5 and also to permit the latch-bar to pivot properly when it is tripped.

Attached to the dipper door I is a pair of support members I'I and I8 which contain holes through which shafts I9 and 20 extend. These may be held in place by means of nuts 2I and 22, and may have square heads 4I and 44 on the opposite ends. Attached by welding or otherwise to the supports II and I8 are

plates

23 and 24 which serve to support a protective cover 25 added to prevent dirt from entering the latch. As may be seen in Figure l, the plates have a flange 26' extending inwardly. These are drilled and tapped to take cap screws 21 which hold the cover plate 25 in position. A latch-bar 28 is pivotally mounted on shaft 20 by means of a hole 29 extending therethrough. This hole may be located intermediate the length of the latch-bar 28 and is preferably near the center. The position of the hole will determine to a large extent the amount of force required to hold the latchbar in position and to release it. The lower end of the latch-bar may have a curved or arcuate end being relieved inwardly adjacent the dipper so as to engage the curved face of stop i and thus guide the latch-bar into the latch-bar slot I4 when the door is slammed shut and the latchbar is moved into the latched position as shown in Figure 3.

The upper end of the latch-bar is likewise curved inwardly but the face is preferably extended beyond the width of the bar by a projection 30. This projection may serve as a stop by resting against the clipper door I0 and preventv substantial vibrational movement when the bar is in latched position. Moreover the face is extended so that the tripping mechanism 3l will have a place to rest when the latch is in tripped position shown in Figure 4.

When the latch-bar is in latched position as shown in Figure 3, it is held there by means of a trip 3| which is pivotally mounted on shaft I9 by a journal 32. Journalled in the leading or lower edge of trip 3l is a roller 33, which rests against the back face of latch-bar 28 when it is inlatching position (Figure 3) but which rides along the upper curved face of the latch-bar when it is in tripped position as is shown in Figure 4. This roller preferably has a bearing 34. The shaft I9 is prevented from turning by means of' set screws 35 or other conventional means. The journal 32 for shaft. I9 is located above the upper end of latch-bar 28; so thatwhen'the trip is released the roller 33 describes an arc beginning outwardly and upwardly over the end of the latch-bar.

There is preferably a slight depression or groove extending laterally across the latch-bar 28 near the upper end to aid the roller and trip mechanism to hold latch-bar 28 in latching position.

Attached to the trip 3l near the forward face Tis a'link 36 which extends approximately parallel to the door and out through a hole 31 ,in the cover 25. A flexible bellows,A not shown, may y seal this hole.A A link orloop is placed in the end-l of link 35 for attaching -cable 38.V which runs tof, atrip mechanism which is 'mechanically pow-g ered in the case of power driven shovels. yByfJ pulling upward on cable 38 the leading or for-5"V ward edge of the trip mechanism 3`I is caused to pivot upwardly and outwardly disengaging itself from the vertical face of latch-bar 28 and thus permitting the weight of the load on the clipperdoor to thrust the door outwardly into the position shown in Figure 4. Y Y

A spring retaining member such as arm 33 extends from the trip mechanism at a point remote from roller 33. That is, the pivot point lies between the arm 38 and the roller 33 so that movement of either exerts an opposite effect on the other member. A spring 4B urges the arm away from the dipper door. Thus, referring to. Figure 3, when the latch is in latched position the spring urges roller 33 against the back face` of latch-bar 28 Aand prevents it from pivoting around point 29. The trip mechanism is operated Vby momentarily raising the leading edge of thei trip including roller 33, thereby permitting latch, bar 28 to pivot due to the weight pressing against the door. As it pivots, roller 33 rides up and over the end of bar 28 and the lower end of Vbar 28 rides free of latch-bar slot I4 and the dipper door is free to open. -The action in disengaging the latch-bar from the slot is, in effect, a rolling motion rather than a sliding motion as in the conventional latches.' The slot .I6 in. the door prevents more than limited' pivoting of the latch-bar, the lower end of which must clear the sill.

The roller 33 nowgis pressed against the curved' face of the upper end of bar 28 so that; the bar ,isprevented fromv dropping back into latching position and so that the lower end will be held in a position to clear the: sill when the door subsequently swings shut; This is essential to the successful operation of the latch.

Spring Y 40 is held in ,place by conventional.. means shown as

projections

45 and 46 on the door-and arm 39 respectively. The spring is comparativelywea-k sinceV it need only bestrong enoughY to overcomethe-tendency of arm 28 to pivot.

Refer-ringto Figure 7, this'is aV detail of one.

means ofA associating shaft 2U with the mechanism. A square head 4I is attached to the shaftfwhichis driven through a hole in support I 8.` The shaft is prevented from turning by meansV ofalug 42. The opposite end of shaft 2B is threaded to receivewasher 43 andi nut 22. The latch-bar 2S forms a journal for this shaft andthe-latchebarpivots-around the shaft. Preferably the latch bar is of hard steel so that most of the wear occurs-onsha-ft 20. When the shaft becomes-worn, anew bearing surface can bepresented by merely withdrawingr the shaft and turning it a, .quar.ter turn. Thusthe bearing surface can be renewed three times before a new shaft must be supplied. Shafts I9 and 20 are preferably identical. An alternative structure of the latch-bar provides that the shaft 2Q. may beV made integral with` latch-bar and bearing provided, e. g. pillow bearings, to provide pivot means for the bar. As illustrated, provision is made for lubricating the pivotable bearing by means of a counter sunk grease fitting and a hole drilled through the shaft and openings within the bearing.

A shield or cover E' over opening I6, may be provided to protect the; latch-bar, 28 from damage and dirt. There is an opening below the cover 25 to allow any dirt that gets into the mechanism to work free. When associated with the dipper of a power driven shovel, the mechanism operates in the following manner.

As shown in Figure 3 the latch-bar 2B is approximately parallel to the dipper door. The lower end of the latch-bar is associated with the latch-bar slot I4 and thus prevents the dipper door from opening. The spring 40 thrusts against arm 39 thus urging the roller 33 against the latch-bar 28. 36 or cable 38.

When the dipper is raised into position to be dumped, tension is applied to cable 38 usually by means of a motor which drives a suitable cable drum. Only a momentary pull is required and this may be usually done with a fractional horsepower motor since it is only necessary to overcome the action of spring li in order to release the trip. Once the trip mechanism begins its outward and upward movement, the weight of the load pressing against the door causes latch-bar 28 to pivot around point 29 and move into the position shown in Figure 4. The motion is a rolling motion, not sliding, and the force necessary is provided by the weight of the load, notthe tripping mechanism. rIhe roller 33 rides along the curved surface of the upper end of the latch-bar 2t. The latch-bar is prevented from moving more than a limited distance since it strikes the upper part of slot I e in the door. The trip motor operates only momentarily and immediately releases tension on cable 38 so that. the spring di) again exerts its pressure. It thrusts roller 33 against the inwardly curved surface of bar 28 and prevents it from moving of its own weight, back into latch position. Thus bar 2B is held so that the lower end will clear the sill as the door subsequently swings shut which it would not do if the latch-bar could assume a position parallel to the door before the lower end cleared the sill. Any suitable retaining member may be employed to limit the pivot of the latch- No tension is applied to link 6. bar-l andA the door may-be reen-forced at the point where the bar strikes.

When the dipper is lowered, the door swings-` shut-'because of its-own weight, bringing the lowercurved-surface-,of latch-bar 28 into` contact with thecurvedsur-face of the-stop l5. As-theweight continues to press against the latch-fbar, it is guideddownwardly causing it to pivot atpoint 29. Since the strengthvof: the spring is too small to: resist ther weight of the door, the roller 33 rides along the upper curvedk face of the latch-bar; and over the projecting pointr until it assumes the position shown in Figure 3 where it prevents further pivotal action of the latch-bar-untilit l is-releasedby'a pullon cable 38.

Conventional types of oilers may be applied. A hole-lli isprovided in plate 23 to reach an oiling mechanism in the-end of shaft I 9.

It should be understood that this inventionis not limited to the exacbforms shown orA described. v i

I claim as my invention:

1. A latchruseful on power driven dippers'which comprises spaced supporting members attach-` able to a door, a shaftr through two of said supporting-members, a latch-bar pivotallymounted on; said shaft intermediate the length ofthe bar, saidy bar being relieved arcuately at each end inwardlyV toward thev door,y the lower end-'of said bar being engageable with a` slotted sill member, a shaft mounted on two of said supporting mem-y bers, a trip member mounted pivotally on the shaft, a roller associated with one end of said trip member and engageable with the back of said latch-bar when it is in latching position, an arm extending beyond the pivot point of said trip member, a spring normally urging said arm away from the door so as to engage said roller with the end of said bar, and means for urging said arm toward the door thereby overcoming the eect of said spring and moving the roller away from said bar thereby permitting the bar to pivot.

2. A latch for doors carrying weight against the latch when the door is to be opened, comprising a latching device attachable to the door, said device comprising a pair of spaced shaft supports, shafts extending therethrough, a latchbar pivotallymounted on one of said shafts intermediate the length of said bar, said bar being adapted to engage a sill member of the door, a trip member pivotally mounted on the other shaft, said trip member comprising a roller engageable with said latch-bar to prevent pivoting thereof when in latching position, and tending to urge the latch-bar out of latching position when in non-latching position.

3. A latch comprising, a latch-bar support, a latch-bar pivotally mounted on the support at a point intermediate the length of the bar, a trip support, a trip pivotally mounted thereon adjacent but spaced from one end of said bar and engageable therewith to prevent pivoting of the bar when it is in latching position, the opposite end of the bar adapted to engage a cooperating latch keeper, means normally urging said trip against said bar and means to which force may be applied to oppose the action of the last named means, thereby removing the retaining effect of the trip on said bar and permitting pivoting of said bar.

4. A latch comprising, a latch-bar support, a latch-bar pivotally mounted on the support at a point intermediate the length of the bar, a

trip support, a trip pivotally mountedthereon adjacent but spaced from one end of said bar andV engageable therewith to prevent pivoting of the bar when it is in latching position, the opposite end of the bar adapted to engage a cooperating latch keeper, means normally urging said trip against said bar and means to which force may be applied to oppose the action of the last named means thereby removing the retaining effect of the trip on said bar and permitting pivoting of said bar, and a cover mountable over said latch-bar and said trip, said cover having an opening for said force applying means and an opening for the latch-bar.

5. A door latch for doors subjected to heavy door opening pressure, said latch tending to unlatch under the iniiuence of said pressure when released, said latch comprising a support adapted to be mounted on a door; a latch bar pivotally mountedon said support intermediate the length of the bar, the forward end of said bar being adapted to selectively engage or disengage a cooperating latch keeper when the bar is pivotally rotated in one direction or the other; a trip member adapted to engage a surface on the rear end of the bar when in latching position thereby preventing rotation of the bar, said trip member also adapted to engage another surface of the rear end of the bar to urge the bar out of latching position when the bar is in non-latching position; means for impelling the trip member into engaging position with the bar, control means to actuate the trip member out of engaging position atV will against the influence of the impellingl means thereby permitting the bar to rotate under the influence of a pressure against the door.

6. The latch of claim 5 characterized by the fact that the rear end of the bar comprises a cam surface and the trip member comprises a roller adapted to be engaged therewith.

'7. The latch of claim 5 wherein the latch bar is substantially straight and centrally pivoted.

8. The latch according to claim 5 wherein the impelling means is a spring.

WALTER A. HILGEMAN.

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

` UNITED STATES PATENTS Number Name Date 383,886 Jackson June 5, 1888 829,825 Alexander Aug. 28, 1906 971,423 Walters Sept. 27, 1910 982,087 OConnor Jan. 17, 1911 1,725,858 Esters et al Aug. 27, 1929 2,095,322 Elmes Oct. 12, 1937 2,339,073 Hobson et al. Jan. 11, 1944 FOREIGN PATENTS Number Country Date 155,050 Great Britain Dec. 16. 1920.