US2625128A - Roller hatch beam - Google Patents

Description

Jan. 13, 1 953 G. SIPKIN 2,625,128

ROLLER HATCH BEAM Filed Aug. 19, 1948 s Sheets-Sheet 1 INVENTOR. GEORGE SIPKIN ATTORNEY Jan. 13, 1953 e. SIPKIN 2,625,128

ROLLER HATCH BEAM Filed Aug. 19, 1948 3 Shaets-Shaet 2 3 7 22 INVENTO F|G.2-A GEORGE SIPKIN ATTORNEY Jan. 13, 1953 G. SlPKlN 2,625,128

ROLLER HATCH BEAM 3 Sheets-s 3 Filed Aug 19' 48 Fl -1NVENTOR TTORNEY Patented Jan. 13, 1953 UNITED STATES PATENT OFFICE (Granted under Title 35, U. S. Code (1952),

sec. 266) 15 Claims.

The present invention relates to a roller hatch beam, and more particularly to a roller hatch beam with retractable wheels, whereby the beam maybe made movable or stationary, as desired.

It has been common practice in the past, When opening a ships hatch, to remove the top planking, and then by some hoisting means, a Winch for example, to remove the cross beams which support the planking; the entire operation being more than somewhat cumbersome and laborious.

There are devices known in the prior art which wheel, rolling on a V-shaped track, 'at each end of the beam, which has the disadvantages of not only permitting the beam to turn slightly askew so-that it will often jam, but also of allowing it to tip over easily, with the result that such planking which has not been removed may iall'thro'ugh the hatch-opening endangering personnel who may be below decks. Other prior art devices, in raising the beam up onto its wheels, utilize a lifting mechanism which has a long handle extending over the side of the hatch "coam'ingywith the result that in order to operate the device a good bit of space is needed beyond the hatch coaming, through which to swing the handle. This space may not always be available if the deck is crowded with other equipment, 'or cargo, and furthermore the long handle maybe hazardous to personnel.

The present invention corrects the deficiencies noted above and provides a roller hatch beam which is easy to operate and which ofiers no hazard'to the safety of the ship's personnel. The beam functions in cooperation with a novel mechanism comprising a lcverand a cooperating inclined plane which raise the beam uponrollers, the lifting mechanism being inexpensive to construct, and requiring that only a minimum amount of force be applied by the operator. When the operating lever has beenmanipulated to raise the beam, it automatically locks in the hoistedp'osition so that there is no chance of the beam accidentally dropping down again; this feature being a distinct improvementover prior known devices. While in its hoisted position, ready for rolling,'the beam is supported by'two wheels at each end'of the beam, the wheels being sufiiciently spaced apart so that tipping of the beam and any angular side movement are reduced to a minimum. Furthermore, the handle of the raising mechanism never extends outside the boundary ofthe hatch coaming, and not only servesas a means for hoisting the beam up onto the rollers, but also furnishes a handle for pulling 'the beam along its track. Once a beam is hoisted into the raised position and moved to one end of the hatchway, it cannot be left inthis raised position and free to roll, as the ship rolls, inasmuch as the operating lever'is detachable and must be removed in order to operate the raising mechanism of the next beam. In addition to the above advantages, the operating lever has an arrangement which makes contact against the side of theinclined'plane, when thebeam is being lowered, thereby giving a braking action sothat the beam-may be lowered slowly, if desired. From the above discussion,it is obvious that the present invention contains many improvements over similar prior known devices.

The primary object of the present invention is the provision of a roller hatch beam of an improved character, which may be readily rolled along tracks attached to the hatch coaming.

Another object is the provision of means whereby the beam maybe raised from its normal,

'o'r'rest, position and supported. on wheels while it is being moved to one-side of the hatchway.

A further object is the provision of means whereby the beam is automatically locked in a raised position, so that it may be freely moved without danger of falling.

A still further object is the provision of a detachable-operating lever forraising the beam and for supporting it when it is in the raised position.

A still further object is the provision of friction means to aid'inlowering the beam slowly to its rest position.

=Stillanother object is the provision of a roller beam which cannot under ordinary conditions be left in a raised position, and free to roll, once it has been moved to one end of the hatchway.

Yet another object of the present invention is the provision of a roller beam which extends almost to the edge of the hatchway, thereby furnishing adequate support for the hatch covers.

Other objects and many of'the attendant advantages ofth'e invention will be readily appreciated as the-same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 shows a top plan view of a hatchway, in partial section, with the hatch boards and hatch beams in place.

Fig. 2 shows a side elevation of the hatchway with the hatch boards and hatch beams in place.

Fig. 2-A is a side elevation showing all of the hatch beams rolled to one side, and nested at one end of the hatchway.

Fig. 3 illustrates a front elevation view in partial section showing the hatch beam in its lowered, or rest position.

Fig. 4 illustrates a front elevation view in partial section showing the hatch beam in its raised position.

Fig. 5 shows a top plan view taken along the line 5-5 of Fig. 4, illustrating how the rollers are mounted and showing certain parts in plan.

Fig. 6 illustrates a side elevation of the invention showing the hatch beam and rollers.

Fig. '7 shows a front elevation of the inclined plane, greatly enlarged.

Fig. 8 shows an enlarged plan view of the inclined plane with the side shoulders of the operating lever positioned on either side thereof.

Fig. 9 illustrates a perspective view, in partial section, of the operating lever and the aperture through which it is inserted.

Fig. 9-A is a front elevation showing the operating lever being inserted in the aperture in the hatch beam.

Fig. 10 shows an enlarged view of a preferred embodiment of the operating lever.

Fig. 11 shows another embodiment of the operating lever greatly enlarged.

Fig. 12 illustrates a modified form of mounting for the inclined plane.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in Fig. 1 a typical ship's hatch with hatch beams 22 inplace to support the boards 2i Normally, the beams 22 are spaced at regular intervals across the hatchway, but when they are raised, and rolled to one side, they assume the positions shown in Fig. 2-A.

In the present invention the hatch beam 22 is usually of the I-beam type, or the like, having an upper flange 24, (Figs. 3 and 4) a connecting web 25, a lower flange 26, and a supporting shoulder 26', each end of the beam resting on a ledge 21 attached to a hatch coaming 23. When lowered, the supporting shoulder 26' is engaged on both sides by small blocks, or stops 28, aifixed to the ledge 21, which act as safety devices to keep the beam in position.

To the webbing 25 of the beam 22 there is attached a support, indicated generally as 29, which includes arms 29' supporting a pair of roller wheels 34 and an inclined plane or cam surface 33 thereon. There is preferably, but not necessarily, an arm 29 on either side of the web 25, the arms 29 being constructed of U-shaped angle irons having their, broadest face near the-web 25 and their parallel faces 30' extending normal thereto. See Figs. 3, 4, 5 and 9. Extending substantially the full length of the arms 29', and positioned midway between the parallel faces 30' is a strengthening fin 3|; the entire support 29 being mounted by means of a bolt 30, or the like, passing through a hole 3! in the web 25 so that the support 29 and its associated components are free to pivot. The hole 3| in the web r 4 25 is slightly larger than the diameter of the bolt 30, whereby the support 29 is capable of a small amount of lateral movement with respect to the beam 22, as well as the pivoting movement about the bolt 39, the purpose of these movements being described hereinafter.

The free end of the support 29 has a framework 32 of suitable cross section, such as the I cross section shown in Fig. 7, which is joined to arms 29' at 33 by some suitable means as by welding, and which forms a base for a cam surface 33 and a pair of wheels 34, the wheels 34 being arranged to rest on a V-shaped track 35, suitably mounted on coaming 23 by an L-shaped bracket 36. The wheels 34 are rotatably mounted on a plate 32 which is broader than framework 32 and attached thereto as by welding, whereby the wheels are spaced relatively far apart so as to minimize tipping of beam 22. A heading 3'! on the underside of a bracket 38, which is secured to the coaming 23, is provided above the wheels for the purpose of maintaining the wheels in rolling contact with the track 35. The bracket 38 also serves as a support for the end hatch board when it is put into place. On the underside of the framework 32 there is a webbing 42 (Fig. '7) which joins the two flanges of the framework, in order to give it additional strength.

Cooperating with the cam surface 33, several features of which will be described hereinafter, is a detachable lever 40, the lower end of which is provided with a freely rotatable wheel 39 (Fig. 10), arcuate shoulders 50, whose purpose will be described hereinafter, and side shoulders 49 which may have any configuration but are preferably arcuate. The lever 40 is provided with a pair of arcuate shoulders 49 which are relatively broad compared to a long and fairly narrow aperture 48 in the I-beam face 24 (Fig. 9-A) through which the lever 40 is inserted, the shoulders 49 extending on either side beyond the boundaries of aperture 48 when rotated after insertion therethrough (Fig. 9) and acting as a fulcrum when contacting the underside of the upper face 24 of the beam 22. The lever 40 has a chain 5| attached to its handle, by means of which the lever 40 may be operated, or stowed away when not in use. The modified lever as seen in Fig. 11 has a rounded section 52 instead of a wheel, while the arcuate shoulders 50 are omitted entirely. In both the preferred and modified embodiments of the lever 40, the upper tion 4! is a recess 43, and shoulders 41 which cooperate with the indentation M and shoulders 46 of the lever 40 to serve as safety looks as will .be described hereinafter. The highest end of the cam surface 33 terminates in a buttress 44 providing a stop for the wheel 39. As can be clearly seen in Figs. 5 and 9, the cam surface 33 is displaced from the midpoint of the framework 32 and is sufficiently positioned to one side of the web 25 to permit the lever 40 to be inserted through the aperture 48 and into contact with the inclined portion of the cam surface.

The inclined plane or cam surface 33 may have either a straight or curved inclined portion as it "is the amount of rise of thecam surface which determines the amount of rise of the beam 2-2, 'theparticular configuration of the cam surface being-chosen for ease of operation inboth rai-s'ing'andlowering the beam. Theam'ount of rise ofthe cam surface 33' is not very great as it is generally necessary to raise the beam '22 not more than one inchand, as will become apparent as the description proceeds-part of this rise is inherently produced by the motion of the lever 40 as it travels over the inclined portion of the cam surface 33.

On both sides of the center web 25 of beam '22, and on the inside of arms 29', there are mounted fine tooled blocks 45 to provide spacers for the movable ends of the arms 29', as well as sliding contacts, so that the arms may move freely.

Referring to Fig. 6' there is clearly shown the support 23 for the roller wheels 34', as Web as a shoulder 26', and their position relativ to the beam. The shoulder 26 is substantially broader than the bottom flange 26 of the beam, and is placed approximately at the center of gravity of the beam, there being strengthening line '56 attachedto the web 25. When the beam is in its lowered position, the broad shoulder '26 resting on the ledge 2? acts to cooperate with the spacedapart rollers 34 to give the-beam considerable stability, and to thereby further safeguard against any tipping of the beam.

In'the modification shown in Fig. 12, the cam surface 33 rests on one of the arms 23, and is slidablymounted on a pairof rods 53 which connect the upper flange 24 and lower flange 26 of the beam 22 for a purpose to be later disclosed.

In operation, after the hatch boards 2| are removed, the operating lever 40 is inserted in the manner shown in Fig. 9-A, through the aperture 48 in the top of the hatch beam 22 and turned 90 to the position illustrated in Fig. 3 so that the shoulders 49 of the lever extend on either side of the aperture 48 and below the top flange 24 of the beam, and also so that the small wheel 39 on the lower end of the lever is aligned with the inclined cam surface 33. The lever is pulled to the right until it engages the right side of aperture '48 around which it pivots as shown in Fig. 9. When the lever is pulled still further towards the edge of the hatchway the shoulders '46 on lever 40 prevent the lever from becoming disengaged from cam surface 33, and the wheel 39 is caused to mount the inclined plane thereby raising the adjacent end of beam 22 off ledge 21. The wheel 39 finally drops into the depression 4| at the top of'surface 33 after lever 43 has passed its vertical position (Fig. 4) and the lower shoulder 46 of the lever locks behind the shoulder 41 in the'vertical side of the cam surface 33 when lever 40 is pushed or pulledslightly to one side.

It will thus be seen that the beam is double locked in its raised position by a combination of three different safety features for when lever 40 passes through its vertical position, it passes over dead-center and the beam 22 drops slightly to lock lever 40 into its new'p'ositi'on. Furthermore, when wheel '33 falls into depression. on cam surface 33, it cannot be removed therefrom except by the exertion of considerable force. When the lever 43 is pulled or pushed slightly to one side, which will occur without deliberation when the operator employs the lever to either pull or push the beam 22 towards one end of the hatchway, the sidewise motion of shoulder 43 of 'the'lever into the recess 43 on the side of cam surface i3 3 causes shoulder 46 'to 'catch behind the shoulder 41 of recess 43 thereby to prevent lever 40 from pivoting about its-shoulders in a direction to cause lowering of the beam. Still another safety feature which prevents accidental lowering of the beam resides in the movementof one of the arcuate shoulders 50 of the lever 40 into engagement with the arcuate surface of depression 4| at the top of cam surface 33 when lever 40is moved'slig'htly to one side as described above, as this substitutes a frictional surface for part of the anti-friction surface of Wheel 39 in contact with the surface of depression 4].

The opposite end of beam '22 is provided with a similar support 29 adapted to be engagedby a Second lever 40 for raising that end of the beam and looking it in a raised position in the manner described hereinabove.

It should be noted that part of the lift of the beam is i-nhere'htl'y produced by the pivoting of the lower end of lever 40 aboutthe shoulders '43 as the lever moves to the right from the position shown Fig. athrough the position of Fig. 9, to the finai raised position of Fig. 4, so that the initial angle of lever Mlwith respect to vertical is greater than the final angle whereby an amount of lift has been afforded the beam which is a function of the distance between the shoulders 49 and the line on the wheel 39 at which it makes contact with the cam surface 33. Because of this inherent lift, the lift provided by the cam surface may be made correspondingly less and in some cases may even be reduced to zero.

The beam has now been raised sufliciently at both ends for the projections 26' to clear the stops 28, and the rollers 34 and track 35 are supporting the entire weight of the beam thereby permitting the levers 43 at each end to be used as handleafor pulling-the beam to one end of the hatch'way, th'echain iil being employed when the deck adjacent the hatchway is too crowded to permit grasping the lever 43. The beam is then lowered again and the levers removed, whereby they may be inserted in the ends of another beam for rolling "it to one side, and this process is continued until all of the beams are nested in one corner, leaving the hatchway clear.

When any'of the beams are to be lowered from their rollers, the lever 40 is first pushed transverse y to the beam so as to make the lever'shoul- 'der 46 ofthe lever-clear the safety shoulder 41 in the side-of the-cam, and to m'ake'one of the armate friction shoulders 53 rather than the entire wheel '39 on the lever make contact with the cam rered'wi'thout endangering the safety of the operator" as'it can be seen that when the lever '43 is pushed to the left from its position in Fig. 4 in order to lower the beam, the wheel 33 will resist any tendency to leave the depression 4! in the same surface 33 until the shoulders 49 of the lever have been 'fo'rcedto travel under the upperfacaz l'of thebeam as the lever moves from abutment with the right side of the aperture 48 to abutment with theleftside of the aperture 48, the entire lever pivoting about the wheel 39 during this portion of the maneuver and first slightly raising the beam as the lever goes through its vertical or dead center position and then permitting the beam to begin its downward course until lever 48 abuts the left side of aperture 48. When this occurs, the lever pivots about the left side of aperture 48 in the vicinity of the lever shoulders 49 and the wheel 39 is cammed out of the depression 4| (Fig. 3) and commences to roll down the cam surface 33 under braking control of arcuate shoulders 50 and shoulders 46 of the lever as heretofore described thereby permitting the beam to be lowered gradually until shoulder 28' rests on ledge 21. Lever 48 may now be removed and employed for raising or lowering other beams, it being apparent that if only two levers are provided for an installation, it is impossible to leave more than one beam in its raised position wherein it is free to roll with the roll of the ship and provide a hazard to the safety of the personnel.

The beams may all be returned to their normal positions in the hatchway in the manner heretofore described. Once all of the beams are back in place and are in their normal positions between the stops 28, the operating levers are removed and the hatch boards 2i put back into place.

It will be noted that lever 48, shown in Fig. 10, provides a means for raising the beam with little or no friction by reason of the anti-friction effect of the wheel 39 whereas the beam is lowered gradually by proper employment of the friction shoulders 58 and 46. If desired and under conditions where friction is not a factor such as where light weight beams are to be raised, the wheel 39 may be omitted and the lever illustrated in Fig. 11 may be employed in which the friction surface 52 is designed to engage the cam surface 33 in both the raising and lowering operation.

Any irregularities in the track 35 are compensated for by the lateral movement of the support 29 with respect to the beam 22, due to the large hole 31 provided about the bolt 38. However, the play of support 29 may in some cases be deleterious to the operation of cam surface 33 in the arrangement of Figs. 3 and 4 for the reason that the cam surface may move relatively to the lever 40 as the latter pivots about the sides of the aperture 48. To obviate this, the embodiment of Fig. 12 has been devised to provide a cam surface 33 similar to that previously described which is mounted on a slide 54 slidable vertically on rods 53 fixed to the upper and lower faces 24 and 26 of the beam 22, the bottom of the cam surface 33 resting freely on the arm 29 thereby to remain unaffected by lateral movement of the arm 29'.

The lower portion of the slide 54 acts as a guide for the arm 29' which is free to pivot on beam 22 between the slide 54 and the machined pad 45 but is prevented from moving sidewise thereby. As is readily apparent, the operation of this embodiment of the invention is similar to the previously disclosed arrangements.

It is to be understood, of course, that in every instance like units of the invention are mounted on each end of the hatch beam, and both units must be operated in order to completely raise the beam so that it may be rolled along its track.

In the description and drawings the cam surface has been shown as being located parallel with the hatch beam making it necessary to move the operating lever also parallel with the beam when raising and lowering the beam but it is to be understood that the embodiment of the invention is not to be so limited. Should it be so desired that the lever be moved transversely to the beam, or at any other angle relative thereto, the cam surface can be correspondingly mounted at the same angle, and the invention will function just as effectively as before. Cam surfaces may also be attached to the underside of the upper face 24 of beam 22 adjacent and parallel to the sides of the aperture 48 so that they may be acted upon by shoulders 49 of the lever 48 as the lever moves longitudinally of the aperture 48. The total lift of beam 22 will then be due to the lift produced by the cam surfaces adjacent aperture 48 plus that produced by cam surface 33 and inherently by lever 40.

Thus, from the foregoing description of the instant invention, it is obvious that the device provides a roller hatch beam of an improved character which automatically looks when in a raised position, and which can be easily and safely rolled to one side of a hatchway. It also has the further advantage of providing a detachable operating lever which requires a minimum amount of space in which to function, and which has friction means for permitting the beam to be lowered slowly from its raised position to its nor mal position of rest.

It will be apparent that the foregoing disclosure relates to only preferred embodiments of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. A roller hatch beam construction comprising members including a hatch beam and a supporting and rolling unit pivotally mounted adjacent one end of said beam, rollers attached to said supporting and rolling unit, an inclined cam surface supported by one of said members, and a lever having transversely extending portions between said beam and inclined cam surface pivotally acting against said hatch beam and said cam surface for raising and lowering the beam.

2. In combination, a hatch beam, a hatch framing, a track mounted on said framing, supporting and rolling units on each end of the beam comprising movable arms pivoted to said beam at a point spaced from the ends of said beam, a plurality of rollers mounted on the free ends of the pivoted arms and adapted to engage said track, an inclined cam surface supported by each of said arms, and a lever having transversely extending portions between and engaging the said cam surface and the beam for raising and lowering the said beam.

3. The combination of claim 2 wherein said beam has an upper flange and a first of said lever portions engages the underside of the upper flange of the beam.

4. The combination of claim 2 wherein said beam has an upper flange with an aperture therein, and said lever pivots about the underside of the upper flange of the beam and extends through an aperture in said upper flange of the beam.

5. The combination of claim 2 wherein said beam has an upper flange with an aperture there- 'in, and said lever pivots about the underside of the upper flange of the beam and extends through 9 an aperture in the flange of the beam, the said lever being detachably inserted through the said aperture.

6. The combination of claim wherein one end of the lever is substantially U-shaped and has a wheel in its center adapted to engage said cam surface.

' 7. A self-locking roller hatch beam construction comprising a hatch beam, movable arms pivoted to said beam at a point spaced from the ends of said beam, a plurality of rollers mounted on the free ends of said pivoted arms, a cam surface supported by said arms, an operating lever arranged to act against the cam surface and pivotally against the beam to raise and lower the beam, one end of the cam surface having a depression therein whereby the beam is automatically locked in a raised position when the lower end of the operating lever pivots beyond dead center and drops into the aforementioned depression.

8. A self locking roller hatch construction comprising a hatch beam, movable arms pivoted to said beam, a plurality of rollers mounted on the free ends of said arms, a cam surface supported by said arms, an operating lever arranged to act against the cam surface and pivotally against the beam for raising and lowering the beam, the lower end of the operating lever being U-shaped with a rounded section for contacting the cam surface, one end of the cam surface having a depression in the face thereof, a second depression in the side of the cam surface whereby a double locking is obtained when the above mentioned rounded section of the operating lever enters the e first depression and one side shoulder of the U- shaped portion enters the second depression as the operating lever pivots past dead center and is moved slightly sidewise.

9. A roller hatch beam construction comprising a hatch beam, a hatch framing, a track mounted on said hatch framing, a pair of movable arms pivoted to the web of the beam and projecting parallel beyond the end of the beam, a roller support connecting and extending transversely beyond the projecting ends of the arms, rollers mounted at each end of the support, cam means mounted on one of said arms, and a lever arranged to act against the cam means and pivotally against the beam for raising and lowering the beam whereby the above-mentioned rollers are made to rollably carry the beam.

10. A roller hatch beam construction comprising a hatch beam, a movable arm pivoted to the web of the beam at a point spaced from the end of said beam, a plurality of rollers mounted on the free end of the pivoted arm, a plurality of rods joining the upper and lower flanges of the beam, a member slidable on said rods, one end of said member being in the shape of an inclined plane and freely resting on the said pivoted arm, and raising means associated with the inclined plane and the beam to raise and lower the beam.

11. The roller hatch beam of claim 12 wherein said beam has an upper flange with an aperture therein, and the raising means consists of a lever, detachably inserted through an aperture in the upper flange of the beam and making contact with the inclined plane, the said lever pivoting about the under side of the upper flange of the beam, so that as the lever is operated, the relative distance between the free end of the pivoted arm and the upper flange of the beam is altered.

12. In combination, a hatch beam having an upper flange with an aperture therethrough, a hatch framing, a track mounted on said framing, supporting and rolling units on each end of the beam comprising movable arms pivoted to said beam at a point spaced from the ends of said beam, a plurality of rollers mounted on the free ends of the pivoted arms and adapted to engage said track, an inclined cam surface supported by each of said arms, and a lever detachably inserted through the aperture in the beam, said lever having portions engaging the cam surface and pivotingv about the underside of the upper flange of the beam for raising and lowering said beam, the lever having one end bifurcated with a wheel rotatably mounted between said bifurcations, the wheel being adapted to engage the cam surface, said bifurcations being provided with arcuate shoulders having substantially the same center and radius as the wheel and also adapted to engage the cam surface, and extensions on said bifurcations for limiting sidewise movement of said lever with respect to said cam surface.

13. In combination, a hatch beam having an upper flange with an aperture therethrough, a hatch framing with a track mounted thereon, supporting and rolling units on each end of the beam comprising movable arms pivoted to said beam at a point spaced from the ends of the beam, a plurality of rollers mounted on the free ends of the pivoted arms and adapted to engage said track, an inclined cam surface supported by each of the arms below said aperture, said surface extending lengthwise of said beam, and a lever detachably inserted through the aperture in the beam, said lever having transversely extending portions engaging the cam surface and pivoting about the underside of the upper flange of the beam for raising and lowering said beam, the lever having one end substantially U-shaped and having a rounded section in its center to act against the cam surface.

14. In combination, a hatch beam having an upper flange with an aperture therethrough, a hatch framing with a track mounted thereon, supporting and rolling units on each end of the beam comprising movable arms pivoted to said beam at a point spaced from the ends of the beam, a plurality of rollers mounted on the free ends of the pivoted arms and adapted to engage said track, and an inclined cam surface supported by each of the arms below said aperture, said surface extending lengthwise of said beam.

15. The combination of claim 14 wherein there is a semi-circular depression in one end of the cam surface.

GEORGE SIPKIN.

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

UNITED STATES PATENTS Number Name Date 1,538,024 Chandler May 19, 1925 1,543,661 Baumbach June 30, 1925 2,332,308 Deegan Oct. 19, 1943 2,332,386 Lemon Oct. 19, 1943 2,398,289 Crocker, Jr. Apr. 9, 1946 2,438,846 Deegan Mar. 30, 1948 2,439,288 Evans Apr. 6, 1948

Images