US2619718A

US2619718A - Can opener

Info

Publication number: US2619718A
Application number: US204533A
Authority: US
Inventors: William J Landry
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-01-05
Filing date: 1951-01-05
Publication date: 1952-12-02
Anticipated expiration: 1969-12-02

Description

W- J. LANDRY Dec- 2, 1952 CAN OPENER 3 Sheets-Sheet l Filed Jam 5, 1951 7A: 'i W IVENToR. v WI//fa/WJa/fd/y 1% C Dec. 2, 1952 w, J, LANDRY 2,619,718

CAN OPENER.

Filed Jan. 5, 1951 3 Sheets-Sheet 2 Zf Z6 mma/WJ MM] Dec. 2, 1952 w. J. LANDRY 2,619,718

CAN OPENER Filed Jan. 5, 1951 S'Sheefs-Sheet 3 NVENToR.

ATTORNEK Patented Dec. 2, 1952 CAN OPENER William J. Landry, Blue Springs, Mo., assigner to John C. Hockery, Kansas City, Mo., as trustee Application `anuary 5, 1951, Serial No. 204,533

12 Claims.

The present invention relates in general to can openers, and itv deals 'more particularly with can openers of the type lutilizing a cutter for removing the top of the can, together with a serrated feed wheel or gear for driving the can relative to the cutter during such removal.

This application is a continuation-in-part of Serial No. 129,139, l'ed November 23, 1949.

It is an object of the invention to provide a can opener of this type wherein the cutter comprises a cutting wheel that is readily removable foi` cleaning or replacement.

Another object is to provide a can opener having animproved mechanism for bringing the cutter and feed wheel into and out of operative relationship, which mechanism is economical to manufacture, yet rugged and simple to operate.

A further object is to provide a can opener having improved arrangements for compensating for irregularities in the portion of the can being cut (such as are caused for example, by seams in the can) whereby these irregularities induce little or no resistance to the cutting action, require no greater work on the part of the operator, impose no 'strain on the mechanism, and in no way adversely 'aiiect the cutting action. A collateral object is to provide a can opener mechanism wherein the cutter exerts a uniform pressure on the top of the can. 1

Other and further objects of the invention, together with the features of novelty whereby the objects are achieved, will appear in the course of the 'following description.

In the acoompanying drawings which form a part of the instant specification and are to be read in conjunction therewith, and in which like reference numerals are 'used t'o indicate like parts of the various views:

Fig. 1 is a side elevation of a can opener embodying my invention, parts having been broken away for purposes 'of illustration.

Fig. 2 is a View corresponding to Fig. 1 but with the 'crank and crank housing removed to show, in elevation, the inside 'of the opposite half of the housing and the mechanism mounted thereon.

Fig. 3 is a view of the inside of the crank housing, showing same in inverted position and showing the position of the 'crank hub when the crank is positioned as illustrated in Fig. l,

Fig. 4 is a fragmentary side elevation of my can opener, showing the side opposite that illustrated in Fig. l,

Fig. 25 is a Y'fraggnientary View corresponding to ing. 'f2 but with the mechanism removed to show the inside of the housing alone,

(C1. Sil- 9) Fig. '6 is across sectional view taken along the line 6-6 of Fig. 1 in the direction of the arrows,

Fig. 'Tis a vertical cross section taken along the line 1 1 of Fig. 1 in the direction of the arrows,

Fig. 8 is an exploded perspective vie'w of the inside of the crank hub, Figs. 9, 10 and l1 are views corresponding to Fig. 2, but showing the position of parts at different stages in a can opening operation, and

Figs. 12, 13 and 14 are fragmentary side elevational views of the can opener showing the position of the cutting wheel 'corresponding respectively to the positions of the mechanism shown in Figs. 9, 10 and 11.

Referring more particularly to the drawings, my can opener comprises an elongate, hollow body i6, a cutting wheel IS carried on the side of the body, a cooperating serrated feed wheel or gear 2!) on the same side but below the cutting wheel and a crank 22 on the opposite side of the body for turning the feed wheel, and, as will be made clear presently, shifting the cutting wheel toward and away from the feed wheel.

Conveniently the body of my can opener is mounted on a Wall or similar vertical surface so that it projects horizontally therefrom, and for purposes 'of explanation, the end nearest the wall will be referred to as its rear end, while the opposite extremity will be referred to as its front, or forward end. The body is made up of a pair of matching shell-

like halves

24 and 26 which hereinafter will be referredto respectively 'as the crank housing (best seen 'in Figs. 1 and 3) and the assembly housing (best seen in Figs. 2, 4 'and 5) These preferably are formed by diecasting.

As indicated in Figs. 2 and 6, the assembly housing '26 has at its rear end a laterally nared mounting bracket 25a for purposes of attaching the can opener body to the wall, the mode of attachment, however, forming no part of the present invention. Forward of this bracket, vthe two sections of the body, or shell halves, have their marginal edges in register; the mating edges meet along a vertical plane and. are provided `with complementary rabbets which interlock and form a stepped lap joint 28 that prevents the two halves from shifting relative to one another. They are held together at the forward end of the body by a lateral screw Se and at the rear end by a vertical tab 24a on the crank housing which is inserted in a slot 26o centrally 'disposed in the forward face of bracket 26a. (By removing the screw, it is possible, of course, to swing the forward ends of the two halves laterally apart and then 3 withdraw the tab 24a from slot 2Gb in order to complete the separation.)

Near its forward end, the crank housing 25 contains a large, circular opening encircled by an integral, inwardly extending flange or collar 2te which forms a bearing for the enlarged hub 22a of Ithe crank. This flange is braced and reinforced by a number of generally radial ribs 24d and a pair of vertical webs 24e. The two webs have their inner edges flush with the inner edge of the bearing collar 24e, but the ribs lie wholly below the plane of said edges.

Projecting axially inward from the hub 22a and integral therewith is a central shaft 22h which carries a Ithreaded stem 22o. The serrated feed wheel 2B is internally threaded to receive this stem, its hub 23a being of the same size as shaft 22h, and, in effect, forming a continuation thereof when the two are assembled together; as shown, they are journaled for rotation as a unit in a bearing hole 23h in the assembly housing 26.

Around the latter hole on the inner face of housing 26y is an integral annular bushing 23o, forming a stationary, hollow spindle on which an eccentric cam disk 32 is free to turn. A spring compression washer 34 encircling the crank shaft between this disk and an enlarged shoulder 22d on the shaft biases the disk toward the inner face of the assembly housing 26, and also acts as a light friction brake lon the crank, resisting accidental rotation of the latter.

As best seen in Fig. 5, that portion of the inner face of the assembly housing 23 which lies adjacent the cam disk 26 (and against which the disk is pressed) is a flat surface 23d, irregular in outline but of rather broad area, disposed in a vertical plane. This contains a shallow semicircular groove 25e concentric with the bearing hole 2Gb, and into the groove projects a boss 32a on the cam disk; the opposite ends of the groove serve as stops for the boss, limiting rotation of the disk to approximately one-half turn in either direction.

The supporting and actuating mechanism for ythe cutting wheel of my can yopener comprises a pair of cooperating, essentially

flat arms

36 and 38, which I prefer to stamp in the shape shown in Fig. 2 from heavy sheet metal stock. Disposed one above the other in a generally horizontal position, these arms are cut out to embrace the cam disk 32 and, throughout the major portion of their area, they lie in the same vertical plane as the disk; under control of the disk they enjoy limited movement in said plane, the character of which will be made clearer presently, but they are always held upright and restrained against lateral displacement due to the fact that they are confined in a narrow, vertical guideway or channel, one side of which is defined by the fiat surface 26d, and the webs 261 (whose edges are flush with said surface and may be considered continuations thereof), the other side of the guideway or channel being defined by the innermost edges of collar 24 and webs 24e, which lie in a common plane parallel to but spaced laterally from the plane of surface 26d.

At their forward ends the plate-like arms 33 and 38 are hinged together by a flat ball and

socket joint

36a, 38a, so constructed as to permit the rearward extremities of the arms to swing toward and away from one another a short distance. The distance the latter can move apart about the hinge as a pivot is limited by an inverted L-shaped stop lug 38h, on the lower arni which overhangs a corresponding lug 36h on lthe upper arm. A coiled tension spring 43 having its ends hooked over the rearwardly projecting extremities 36e, 38C, of the respective arms tends to draw them together, such movement being limited however by the adjoining longitudinal edges 36d, 33d, which form abutting stops intermediate the spring and hinge. Forward of the abutting stops 36d, 38d, the confronting edges of the two arms are inversely arched to provide the aforementioned opening for receiving the: eccentric disk 32, the arched portions being so shaped that when the stops are in abutment as shown this opening is essentially circular and just enough larger than disk 32 to allow the clearance necessary for free rotation of the disk in the opening.

Rotation of the eccentric disk tends to shift

arms

36 and 38 as a unit, their movement being guided in part by an elongated opening 33e in the upper arm and a cooperating circular boss 26j projecting int-o the opening from the flat inner surface 26d of the assembly housing.

Immediately forward of this opening a pearshaped at section 36)c of the upper arm 33 is canted from the main plane of the arm, by stamping, and to this are rigidly affixed the inner ends of two laterally spaced spindles l2 and 43. The spindles are normal to the canted surface, ex-

ending outwardly and downwardly through an enlarged opening 26g in the side of the assembly housing 26. The forwardmost spindle 42 is positioned almost vertically above the crank axis and has the grooved cutting wheel I8 rotatably mounted thereon between an enlarged shoulder Ma and a notched latch 33, the latter being pivotally attached to the rearward spindle 44 and engaging in a circumferential groove 42a at the outer end `of spindle 42. An overhanging cover portion 23h flaring outwardly from the top of the assembly housing 26 shelters and partially conceals the cutting wheel E8.

The driving mechanism for the eccentric cam disk 32 comprises a flat dog 48 slidably received in a socket 22e which is disposed in a thickened radial rib 22 f on the inside lof the hub 22a of the crank. In the socket below the dog is a coiled compression spring 50 straddled by inwardly projecting legs 48a on the dog; the spring urges the dog outwardly toward the disk 32 and arms 35 and 38, the exposed edge of the dog being stepped to provide a projection 48h adapted to be received in a notch 32h extending inwardly from the periphery of the disc 32. As best seen in Fig. 2, the edges of the notch are substantially radial to the axis of rotation of the crank, the width of the notch in a circumferential direction being approximately ltwice the thickness of the dog.

When projection 48h is in notch 32h of the eccentric disk, the adjoining face 33e of the dog rides on the fiat surfaces of arms 33 and 33 adjacent the disk; and arm 38 is provided with a camming boss 32 for engaging face 43e and urging the dog inwardly .against the force of spring 5B whenever the dog reaches a predetermined position in the course of rotation of the crank. The boss lies tangent to the disk 32 being highest midway its length and sloping downwardly in either direction from its mid-point to its ends which are flush with the main surface of arm 33.

In describing the operation of my can opener, it will be convenient to choose as a starting point the position of the parts shown in Figs. 1 to 4,

6 and 7. In this position it will be noted from Figs. 4 and 7 that the cutting wheel I8 is lowered so the upper margin of the serrated feed wheel 2'0 is received in the annular groove of the cutting wheel. To separate the two wheels in order'to permit insertion of a can flange between them, preparatory to opening the can, it is necessary to raise the cutting wheel, and this is accomplished by rotating the crank 22 counterclockwise (Fig. 1).

At the beginning of such rotation, dog 48 occupies the position shown by dotted lines in Fig. v2; however, after traveling counter-clockwise with the crank through approximately 180, its projection 4Gb reaches a point over notch 32h and, as the shoulder 46c rides down the descending face 52a of the boss, the projection descends into the notch. With continued rotation of the crank, the dog now turns veccentric disk 32 counter-clockwise (Fig. 2) due to the thrust applied to the edge 32e of the notch by projection 48h. As it turns, disk 3,2

shifts arms

36 and 38 upwardly as a unit, and rotation of the crank through :approximately another 180 thus brings the parts to the position shown in Fig. 9 where the movement is halted due to boss 32a reaching the end of slot 2 6e.

The crank now Ais again in the position shown in Fig. l but due to the upward movement of arm 36, cutter wheel I'8 has been shifted from its initial position (Fig. 4) to the position shown in Fig. 12 wherein it is spaced in appreciable distance above the feed wheel. (It may well be noted at this juncture that if the -operator should release crank handle 22g when the crank is in its Fig. 1 position, the handle would swing downwardly under the influence of gravity and hang in dependent relation to its pivot were such movement not prevented; as previously indicated, however, the compression spring washer 34 acts `as a light rictional brake preventing free rotation of the crank, so it will always remain in the last position to which it has been moved by the operator, and consequently will stay in the Fig. l position indefinitely even though the operators hand is removed from the handle 22g.)

The can opener now is in proper condition to receive the can to be opened, and the flange or bead of the latter is pla-cedV between the cutting wheel, the bottom of this flange resting on the top of the feed wheel as may best be appreciated by referring to the dot and dash lines in Fig. 12. Whileholding the can thus with one hand, the operator with the other hand turns the crank 22 clockwise (Fig. 1) which for convenience may be referredto as the forward direction of rotation. Still being in the notch 32h, projection 48h on dog 48 engages the edge 32d, `and as rotation of the crank continues, turns the disk 32 about its eccentric axis so that the

latter shifts arms

36 and 38 as a unit downwardly until the cutting edge 18a of the cutting wheel strikes the top of the can (see Fig. 13). The initial motion of the

arms

36, 38 is essentially pivotal about the boss 267'; Aand the initial downward movement of :spindle 42 is almost vertical.

The upwardly projecting portion of the 'can flange now is engaged in the annular groove I8b of the cutting wheel, `although still spaced from the bottom of the groove. A boss 26k projecting from the side of the assembly housing 26 below the feed wheel engages the side of the can and assists in holding same upright. As the forward rotation of the crank continues,

the eccentric disk 32 continues to urge the lower arm 38 downwardly, but the upper arm 36 cannot immediately follow due to the resistance imposed upon its downward movement by the top of the can in the path of the cutting wheel. Accordingly, as the lower arm moves downwardly, the upper arm remaining temporarily motionless, the distance between the rearward extremities of the two `arms increases, that is to say, the two arms swing apart slightly about the ball `and. socket pivot at their forward ends. .As this happens, spring 40 is stretched and exerts an increasing force on the upper arm urging same downwardly; this force, of course, is transmitted to the cutter wheel, but except in the case of cans made of very light gauge metal, `is insufficient to cause the cutter wheel to puncture the lid, and accordingly, in most cases the cutter wheel remains in the position shown in Fig. 13 until the separation of

arms

36 and 38 has increased to the point where lug 38h engages lug 36h as shown in Fig. 10.

Now, with continued rotation of ,the eccentric disk 32 thrusting downwardly on arm 38, lug 38h Vexerts a positive downward force on lug 36?) sufricient to move arm 36 downwardly and cause the cutter wheel I3 to puncture the can lid. After puncture, the lid offers less resistance to downward movement of the cutting wheel, and accordingly, spring il draws the upper arm 36 down toward the lower arm 38, reducing the separation between them, but not completely closing the gap between the adjoining

longitudinal edges

36d and 38d. The final movement of spindle 42 is downwardly an-d forwardly, as indicated by the heavy dotted line A in Fig. 14, so that the cutter wheel advances into the metal of the can lid and over the center of the feed wheel with 'a somewhat slicing motion which has been found to facilitate the cutting.

The eccentric disk 32 and dog 48 now are in the position shown in Fig. 11, and, as forward rotation of the crank 22 continues, shoulder 48C of the dog rides up the ascending face 52a of the Vcamming boss 52, raising the projection 48h out of notch 32h. Therefore, the movement of disk 32 halts in the Fig. 11 position, and continued rotation of the crank is effective only to turn the serrated feed wheel 28. Rotation of the feed wheel, of course, advances the can flange relative to the cutter wheel, and it may be noted from Fig. 14 that the portion of the flange behind the wheel is held down by spindle 44 which prevents the can from tilting and stabilizes it in an upright position. Also, lbecause the spindle 44 slopes downwardly toward its outer end, the force exerted by it on the flange of the can is directed obliquely downward and inward toward the body o f the can opener; the inward component draws the edge of the can inwardly, causing the leading edge of the cutter wheel always to hug the inside of the can flange so that the cut cannot migrate toward the center of the lid.A

The operator continues the forward rotation of the crank 22, preferably until the can lid has been completely severed from the body of the can. Oncein each revolution of the crank, projection 48o of the dog drops back into notch 32h but before it can exert any rotative force upon the eccentric disk 32, the dog is again lifted by the camming boss 52 so that the disk remains stationary throughout the cutting operation. Throughout this operation,

arms

36 and 38 remain slightly separated as shown in Fig. 11; the downward thrust on the cutting wheel is that exerted by spring fili on arm 36 which, it will be noted, can swing up or down about the ball and socket hinge at its forward end, thereby to compensate for irregularities in the can. This feature is particularly important in relieving the parts from strain which otherwise would occur, for example, when the bead of the can passes between the feed wheel and cutter wheel. Also, it will be understood that because spring it? always urges cutter wheel It downwardly toward the feed wheel, the bead or rim of the can is firmly gripped between the serrated margin of the feed wheel and the reduced hub portion of the cutter wheel, insuring good traction with the canv rim and proper feeding of the rim relative to the cutter.

After the can lid has been severed, removal of the can from the opener is accomplished by reversing the rotation of the crank. Regardless of the position occupied by the crank when such reversal is initiated, it will be clear from the earlier explanation that when the dog it reaches a position over the notch 32, projection 81) drops thereinto and causes the eccentric disk 32 to turn with the crank back to the position shown in Fig. 9 which raises the cutter wheel see Fig. 12) so that the can flange may be withdrawn.

In order to remove the cutter wheel for cleaning, the crank is turned in a forward direction to lower said wheel to a point where its lower margin just clears the upper margin of the serrated feed wheel-approximately the position shown in Fig. 13. The latch it then is swung upwardly about its pivot to a position clear of the wheel, such movement being facilitated by the outturned lip tta which serves as a finger grip upon which the upward pressure may be applied. When the latch has been swung clear of the cutter wheel, the latter may be drawn axially outward from the spindle and cleaned in any suitable fashion. It then is returned to the spindle and the latch d6 then is swung back down into the position shown where it retains the cutting wheel in place. By rotating the crank in a rearward direction, the cutting wheel now is lifted back to its Fig. l2 position which makes the can opener ready to receive another can for opening.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinbefore set forth, together with other advantages which are obvious and which are inherent to the apparatus.

l't will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and sub-combinations. IThis is contemplated by and is within the scope of the appended claims.

Inasmuch as various modifications of the invention may be made without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

l. In a can opener, a stationary body, a cutter wheel and a cooperating feed wheel adapted to engage the can to drive same, one of said wheels mounted on said body to rotate about a fixed axis and the other supported on the body for movement relative to said one wheel to change the spacing of the wheels, a crank member connected to said one wheel for turning same, a thrust member having operative connection with said body and also having operative connection with said other wheel for imparting movement to the latter relative to said one wheel, mechanism between said members for intermittently actuating said thrust member upon rotation of said crank, said operative connection between said thrust member and said other wheel comprising a lost motion connection including means yieldably resisting loss of motion therein.

2. In a can opener, a stationay body, a cutter wheel and a cooperating feed wheel adapted to engage the can to drive same, one of said wheels mounted on s-aid body to rotate about a iixed axis and the other supported on the body for movement relative to said one wheel to change the spacing of the wheels, a crank member connected to said one wheel for turning same, a thrust member having operative connection with said body vand also having operative connection with said other wheel for imparting movement to the latter relative to said one wheel, mechanism coupling said members during a predetermined rotation of said crank member thereby to actuate the thrust member, means controlling said mechanism to uncouple said members after said predetermined rotation thereby to permit continued turning of said crank member and consequent rotation of said one wheel without further actuation of the thrust member, said operative connection between said thrust member and said other wheel comprising a lost motion connection including means yieldably resisting loss of motion therein.

3. n a can opener of the type having a cutting wheel and a cooperating feed wheel adapted to engage the can to drive same, a body, a shaft mounted on said body to turn about a xed axis, a crank connected to said shaft to rotate same, a member carrying a spindle spaced laterally from said shaft, said member movably supported on said body to shift said spindle toward and away from said shaft thereby to change the spacing between the two, one of said wheels mounted on said spindle and the other mounted on said shaft, a thrust element rotatably mounted on said body to turn about the same axis as said shaft, means releasably coupling said crank and thrust element to cause the latter to turn with the crank during a predetermined portion of its rotation, a second member mounted on said body for movement under the influence of said thrust element upon turning of the same, a lost motion connection between said members, and yieldable means resisting loss of motion in said connection.

4. A can opener as in claim 3 wherein said thrust element comprises an eccentric having a bearing against said second member.

5. In a can opener of the type having a cutting wheel and .a cooperating feed wheel to engage the can to drive same, a body, a shaft mounted on said body to turn about a fixed axis, a, crank connected to said shaft for turning same, a pair of arms disposed side by side and hinged together at one end so the opposite ends of the respective arms are free to move toward and away from one another, stops limiting the extent of such movement in each direction, spring means urging said arms together, said body having means supportmg said arms for movement in a plane normal to said axis, a thrust member operatively connected to said crank and operatively connected to one of said arms intermediate its ends to move same in said plane upon turning cf the crank, a spindle carried by the other arm in such a position that it is urged toward said shaft upon said movement of said one arm, one of said wheels mounted on said spindle and the other mounted on said shaft, and means operative to disconnect said thrust member from said crank after a predetermined rotation thereof.

6. In a can opener of the type having a cutter wheel and a cooperating feed wheel to engage the can to drive same, a pair of coplanar fiat arms disposed side by side, said arms hinged together at one end, spring means urging the opposite ends of said arms together, a stationary body having a guideway supporting said arms for movement in their own plane, the confronting edges of said arms having intermediate the ends of said arms oppositely arched portions forming a circular aperture, a circular disk coplanar with said arms disposed in said aperture and eccentrically mounted on said body for rotation about a xed axis normal to said plane, a shaft mounted on said body for rotation about said axis, a crank connected to said shaft for turning same, means releasably coupling said disk to said shaft to cause them to turn together during a predetermined part of the rotation of the shaft and thereby shift said arms, a slidable connection between one of said arms and said body to guide the movement of said one arm upon such rotation of the disk, a spindlev carried by one of the arms in spaced relation to the shaft, one of said wheels being mounted on said shaft and the other mounted on said spindle.

7. In a can opener as in claim 6 cooperating stops on the respective ones of said arms positively limiting the distance said arms can swing apart about said hinge.

8. A can opener as in claim 6 wherein said slidable connection between said one arm member and said body member comprises an elongated slot in one of said members and a stud on the other member projecting into said slot.

9. In a can opener of the type having a cutter wheel and a cooperating feed wheel to engage the can to drive same, a pair of coplanar flat arms disposed side by side, said arms hinged together at one end, spring means urging the opposite ends of said arms together, a stationary body having a guideway supporting said arms for movement in their own plane, the confronting edges of said arms having intermediate the ends of said arms oppositely arched portions forming a circular aperture, a circular disk member coplanar with said arms disposed in said aperture and eccentrically mounted on said body for rotation about a fixed axis normal tov said plane, a shaft mounted on said body for rotation about said axis, a crank member connected to said shaft for turning same, a dog carried by one of said members, a shoulder on the other member engaged by the dog upon rotation of the crank member to cause the disk member to turn therewith and thus shift said arms, cam means to disengage said dog from said shoulder after predetermined rotation oI" the crank member, a slidable connection between one of said arms and said body to guide the movement of said arm upon such rotation of the disk, a spindle carried by one of the arms in spaced relation to the shaft, one of said wheels being mounted on said shaft and the other mounted on said spindle.

10. A can opener as in claim 9 wherein said cam means is carried by one of said arms.

ll. In a can opener, a stationary body having a feed wheel mounted thereon for rotation about a fixed horizontal axis, a pair of generally horizontal arms disposed one above the other and hinged together at one end so the opposite ends of the respective arms are free to move up and down relative to one another, stops limiting the extent of such movement in each direction, spring means urging said arms together, said body having means supporting said arms for movement in a vertical plane, a thrust member having operative connection with said body and also having operative connection with the lower one of said arms at a point intermediate its ends, means for actuating said member to exert a downward thrust on said one arm at said point, and a cutter above said feed wheel carried by the upper one of said arms at a point intermediate its ends.

12. In a can opener as in claim 11, a slidable connection between one of said arms and said body to guide the movement of said one arm under the influence of said thrust member.

WILLIAM J. LANDRY.

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

UNITED STATES PATENTS Number Name Date 600,595 Pond Mar. 15, 1898 748,993 Southard Jan. 5, 1904 966,650 Bueb Aug. 9, 1910 1,443,783 Bauer Jan. 30, 1923 1,533,599 La May Apr. 14, 1925 1,684,414 Rydquist Sept. 18, 1928 2,148,130 Murdock Feb. 21, 1939 2,383,929 Landry Aug. 28, 1945 2,411,293 Roehner Nov. 19, 1946 2,563,569 Walton Aug. '7, 1951