US3003529A

US3003529A - Peach half twisting head for pitting machines

Info

Publication number: US3003529A
Application number: US761043A
Authority: US
Inventors: Sherman H Creed
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1958-09-15
Filing date: 1958-09-15
Publication date: 1961-10-10
Anticipated expiration: 1978-10-10

Description

PEACH HALF TWISTING HEAD FOR PITTING MACHINES Filed Sept. 15, 1958 S. H. CREED Oct. 10, 1961 3 Sheets-Sheet l INVENTOR SHERMAN H. CREED BY W ATTORNEY PEACH HALF TWISTING HEAD FOR FITTING MACHINES Filed Sept. 15, 1958 S. H. CREED 'Oct. 10, 1961 3 Sheets-Sheet 2 INVENTOR SHERMAN H. CREED BY fw ATTORNEY PEACH HALF TWISTING HEAD FOR FITTING MACHINES Filed Sept. 15, 1958 S. H. CREED Oct. 10, 1961 3 Sheets-Sheet 3 INVENTOR SHERMAN H. CREED ATTORNEY l are llli:

3,003,529 Patented Get. 10, 1961 3,093,529 PEACH HALF TWISTING HEAD BOB PHTTHNG MACHINES Sherman H. Creed, San Jose, Calif., assignor to FMC Corporation, a corporation of Delaware Filed Sept. 15, 1958, Ser. No. 761,043 9 Claims. (Cl. 146-28) This invention pertains to a fruit preparation machine and more particularly relates to apparatus for effectively gripping a fruit during the processing thereof.

In one method of pitting peaches, each peach is bisected by two oppositely moving, aligned blades having serrated edges which penetrate the peach and grip the pit. While the pit is held in fixed position by the blades, twisting heads engage the peach halves and twist the halves in opposite directions to free them from the pit. Due to the nature of the outer surface of peaches, and due to the fact that the peach must not be cut or otherwise marred, considerable difliculty has been experienced in developing a twisting head that can efficiently grip and hold a peach half while the half is twisted relative to its pit.

Twisting heads that have been proposed heretofore have been arranged to apply a predetermined gripping pressure to all peach halves regardless of whether the peach is green or ripe. It is evident that a gripping pressure suitable for gripping a green peach would be excessive for a ripe peach and would cause damage to the peach.

It is an object of the present invention to provide an improved twisting head for a pitting machine.

Another object of the present invention is to provide a novel control and actuating linkage for a twisting head of a twist-type pitting machine.

Another object is to provide a twisting head capable of automatically varying the amount of pressure applied to a fruit in accordance with the state of maturity of the fruit.

Other and further objects of the present invention will become apparent from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a diagrammatic perspective, with parts broken away, of a pair of cooperating twisting heads and the associated drive mechanism of the present invention.

FIG. 2 is an enlarged fragmentary vertical section taken along line 2--2 of FIG. 1.

FIG. 3 is a vertical section taken along line 3-3 of FIG. 2.

FIG. 4 is an end elevation of the twisting head of FIG. 2 taken looking in the direction of arrows 4-4.

FIG. 5 is a vertical section taken along line 55 of FIG. 2.

FIG. 6 is a vertical section taken along line 6-6 of FIG. 2.

FIG. 7 is an exploded perspective of the twisting head of FIG. 2.

FIG. 8 is an end elevation, partly broken away, of a subassernbly of the head of FIG. 7.

FIG. 9 is a plan of the subassembly of FIG. 8, taken looking in the direction of arrows 99 of FIG. 8.

The twisting heads it} and 20 (FIG. 1) of the present invention are adapted for use in a machine wherein the heads are mounted in aligned relation but on opposite sides of a pit gripping blade assembly 30. During the operation of the machine the pit gripping assembly 30, which has a plurality of pairs 31 of pit-gripping blades 32, is arranged to be intermittently indexed in a counterclockwise direction (FIG. 1) to carry a peach from a peach receiving station A to a peach twisting station B which is disposed between the

twisting heads

10 and 20. At station A, a peach is placed on the blades when the blades are in an open position. As the assembly is intermittently indexed, the blades are closed so that, by the time station E is reached, the pit is firmly gripped by the blades and the peach has been substantially bisected to the pit. Each peach may be positioned on the blades at Station A, and the blades may be opened and closed by any suitable mechanism such as that disclosed in the application for patent of Drake et al., Serial No. 691,620, which application is assigned to the assignee of the present invention.

The twisting heads 1i? and 2% are identical but are oppositely disposed as seen in FIG. 1. It is believed that a detailed description of twisting head It will fully disclose the construction and operation of twisting head 20 also. The head lil comprises an outer carrier 40 (FIG. 2) and an inner carrier 42. Two peach contacting members 4-4- (FIG. 4) are connected between the outer carrier 4t and the inner carrier 42, each member 44 comprising a thin, flexible metal strap 45 (FIGS. 4 and 7) which has a socket 46 integrally formed at one end and a curled portion :7 at the other end. The socket 46 is pivotally mounted on a pin 48 (FIG. 4) of the Outer carrier 4th, and the curled end portion 47 is locked on a pin 50 of the inner carrier 42 by a cotter pin 51. A peach contacting rubber pad 52 which is fused on the inner face of each strap 45-, has a grooved inner face 52a adapted to grip the surface of the peach half. The ends of the two straps 44 overlap slightly so that they define a composite flexible band 53 adapted to encircle a peach half.

In operation, the outer carrier 44 is moved clockwise (FIG. 4) while the inner carrier 42 is held against rotation, causing the pins 48 to be moved clockwise and the pins Sit of the inner carrier to be moved radially inwardly in a manner to be described presently. With this arrangement, the band 53 is wrapped around a peach half disposed inside of the band. Then, the inner carrier 42 is rotated counterclockwise causing the pins 50 to be rotated counterclockwise to effect a counterclockwise twisting of the peach gripped by the band. During the initial portion of this counterclockwise movement of the peach, the outer carrier 4%) is stationary and the pins 48 provide a resistance to the counterclockwise movement of the pins 5t) causing the band to be moved further into gripping engagement with the peach. When the desired gripping engagement of the peach is established by this rmisting action of the outer carrier, the outer carrier Will automatically yield and rotate in a counterclockwise direction with the inner carrier to permit twisting of the peach half relative to the pit. It will thus be seen that in the twisting head of the present invention there is provided means for first Wrapping the band tightly around the peach and then rotating the peach while maintaining the band in tight gripping engagement therewith.

The inner carrier 42 comprises a tubular shaft 55 (FIG. 2) which is iournalled for rotation in bushings 56 disposed in a rigid frame member 57 of the peach twisting machine. A sprocket 60 is splined to the shaft 55 by a key 62 which is disposed in a groove 63 in the hub of the sprocket and in a groove 64 in the shaft 55. At its opposite end, the shaft 55 carries a generally circular plate 65 (FIG. 7) which is secured to the shaft by means of a plurality of cap screws 66. As seen in FIGURES 7, 8 and 9, the circular plate d5 has a cut out portion extending diametrically across the plate and providing a wide groove 63 and a relative narrow groove 69. Two blocks 7% and 72 (FIG. 8) are slideably disposed in the narrow groove 69, each block being urged inwardly toward the axis of the circular plate 65 by a tension spring 74 that is connected between a pin 75 on the block and a pin 76 projecting into the wide groove 68 from one side wall of the groove. Each of the blocks and 72 has a pin 80 (FIG. 7) projecting through a guide slot 82 formed in the plate 65 to guide the movement of the blocks. Also, each block 70 and 72 carries one of the pins 50 to which the curled ends 47 of the peach gripping straps are anchored. Each pin 80 is formed as an extension of the aligned pin 50 which is held in the block 70 or 72 by one of the pins 75. A cover plate 84, which has two guide slots 86 to receive the pins 50, is secured by capscrews 87 to the circular plate 65 to hold the blocks 70 and 72 in the groove 69. With this arrangement, the blocks 70 and 72 and the pins 50 carried thereby are mounted for guided movement radially of the circular plate 65, and the springs are arranged to urge the blocks radially inwardly toward the axis of the plate.

The outer carrier 40 comprises an annular plate 90 (FIGS. 2 and 7) which has a cam 91 formed on one face. The cam 91 has two camming surfaces 91a and 91b (FIG. 3) each of which engages a roller 89 on one of the pins 80 of the blocks 70 and 72. The annular plate 90 is welded to a tubular drive shaft 92, that has a pair of spaced set collars 93 and 94 secured thereto and is rotatable on bushings 96 and 97 disposed on the shaft 55. A metal drive band 100 (FIG. is positioned between the collars 93 and 94 with a liner 101 of friction material, such as rubber-coated canvas, disposed between the drive band 100 and the drive shaft 92. The band 100 has two free end portions 100a and 10012 that are pressed together by a nut 104 on a bolt 105 that passes freely through openings in the end portions 100a and 100b and through an opening in an end 101a of the friction liner 101. The nut applies pressure to the hand through a spring 106 that is disposed between the nut and the end portion 100a. The other end portion of the drive band has a bifurcated connector 109 formed thereon which is adapted to receive a pin 107 for pivotally mounting a push rod 108. When the push rod 108 is pushed up wardly, in a manner to be described presently, the drive band 100 is rotated clockwise (FIG. 5) and, through the friction liner 101, the band 100 drives the shaft 92 clockwlse.

The twisting head is reciprocated along the axis of shaft 55 by means of a yoke 120 (FIG. 6) that has two forked arms 120a and 12% each of which is in engagement with a trunnion pin 122 projecting from a split collar 124. Each section of collar 124 has an internal groove 125 (FIG. 2) which receives, in rotatable relation, an annular flange 126 formed on a collar 130 that is secured by a plurality of setscrews 132 to the shaft 55. Thus, the shaft 55 may be rotated without causing rotation of the yoke 120. When the yoke moves the split collar 124- toward the right from the position of FIG. 2, the shaft 55 and the twisting head 10 thereon will be moved to the right to carry the peach gripping band 53 into position around a peach that is held at the peach twisting station B by the pit gripping blade assembly 30. It is to be noted that the splined drive connection of the sprocket 60 to the shaft 55 permits the shaft to slide relative to the support structure of the machine, while the sprocket is held against sliding by a retainer bar 135 which is secured to the support structure and engages the walls of a groove 136 in the hub of the sprocket.

To provide backing pressure for each peach half during the twisting of the peach, a circular plate 140 (FIG. 2) is disposed inside each twisting head at the axis of the head. Each backing plate is secured to the end of a rod 141 that is slidably supported in

bushings

142 and 143 pressed in the hollow shaft 55. A spring 144 is disposed around the rod 141 between a collar 147 keyed to the rod and an apertured bracket 146 that is secured to the support structure of the machine. The spring 144 normally urges the rod 141 toward the right (FIG. 2) to position the circular back-up plate 140 toward the outer end of the associated twisting head. When the twisting head is moved to the right, the spring 144 urges the rod in that direction also so that the plate engages the peach first. As the head continues its movement toward the right, a resilient ring carried by the cover plate 84 engages the plate 140 and, as the head moves to its outermost position, the tube 55 moves away from set collar 147 leaving the compressed spring 144 to apply a predetermined desirable amount to the peach through the plate 140. Accordingly, during the subsequent twisting operation, the plate 140 provides a predetermined selectively variable amount of backing pressure for the peach, thus making certain that the peach will be separated from the pit with a shearing action. After the peach half has been twisted from the pit and the twisting head is moved away from the twisting station, the compressed spring 144 causes the back-up plate 140 to remain for a time in contact with the peach half to hold the peach half against the blade assembly until the twisting head is clear of the peach half. When the tube 55 engages the set collar 147, the spring 144 and the plate 140 are returned to their original positions.

The drive mechanism for the sprockets 60, the yokes 120 and the push rods 108 of the twisting heads 10 and 20 is shown in FIG. 1 and comprises a motor arranged to drive a shaft 156 by means of a belt and pulley drive 157. A gear 158 keyed to shaft 156 is in mesh with a gear 159 formed on a cylindrical earn 160 that is keyed to a shaft 161. The cam 160 has a camming groove 163 which receives a roller follower 164 rotatably mounted on a pin 165 on the lower end of an arm 166 of the yoke 120, that is associated with twisting head 20. The arm 166 is pivoted intermediate its length on a pin 168 disposed in bosses 169 of a bracket 170 which is secured to the support structure of the machine. As the cylindrical cam 160 is rotated, the yoke 120 will be pivoted to move the head 20 toward and away from the twisting station B.

The twisting head 10 is also reciprocated due to pivotal movement of its associated yoke 120 which has a roller follower (not show) disposed in a camming groove 173 of a second cylindrical cam 174 that is keyed to the shaft 161. The camming grooves of the

cylindrical cams

160 and 174 are so arranged that the twisting heads are reciprocated simultaneously but in opposite directions.

A gear is integrally formed on the cam 174 and is disposed in mesh with a gear 181 keyed to a shaft 182. A Geneva driver 183 is keyed to shaft 182 and is arranged to intermittently index a Geneva gear 184 that is keyed to a shaft 185 on which the pit gripping blade unit 30 is secured. It will be evident that the pit gripping unit 30 is indexed in timed relation with the reciprocation of the twisting heads 10 and 20.

A Geneva driver is keyed to shaft 161 and is arranged to intermittently index a Geneva gear 192 that is keyed to a shaft 194 on which two

sprockets

195 and 196 are keyed. The sprocket 195 drives sprocket 60 of twisting head 10 through a chain 198 which is also trained around an idler sprocket 199. The sprocket 196 drives the sprocket 60 of twisting head 20 through a chain 200. Due to the use of the idler sprocket 199, the sprockets 60 of the twisting heads 10 and 20 will be ro tated in opposite directions so that the peach halves engaged by the heads will be twisted in opposite directions.

Each of the push rods 108 which are operatively connected to the drive bands 100 of the outer carrier of the

heads

10 and 20 is pivotally connected at its lower end to a lever 205 that is pivoted at an intermediate portion on a pin 206. The pivot pin 206 is disposed in a bracket 208 which is suitably secured to the support structure of the machine. A double acting power cylinder 210 is provided with upper and

lower fluid connections

213 and 214, and has a piston rod 211 pivotally connected to the lever 205 at a point spaced from the pivot pin 206. When fluid under pressure is directed into the cylinder 210 through an upper connection 213, the lever 205 is pivoted clockwise (FIG. 1) about pin 206 causing the 3) push rod 108 associated with twisting head 20 to be drawn downwardly and causing the drive band 100 connected to the push rod to be rotated counterclockwise. At the same time, the push rod 108 associated with twisting head 10 is moved upwardly causing the drive band 100 connected thereto to be rotated clockwise.

Since all of the drive mechanisms are ultimately driven by motor 155, it is apparent that they may all be operated in timed relation.

In FIGS. 1 and 2 the twisting head ltl is shown in a position withdrawn from the twisting station B. At this time the push rod 10% associated with head 10 is in a lowered position wherein a pin 220 (FIG. 4) on the plate 90 of the outer carrier 40 abuts a stop pin 222 projecting from the circular plate 65 of the inner carrier 42. In this position the band 53 is disposed in an open position. It is to be noted that each of the metal straps 44 has enough resiliency to assume this expanded position which permits the band to be moved into position around the peach half at the twisting station B.

During operation of the machine, a peach to be pitted is delivered to the twisting station B with its flesh bisected to the pit and with the pit firmly gripped between the blades. While the peach is held at this position, the twisting heads 19 and 26) are moved inwardly through the action of the

cylindrical cams

160 and 174, the camming surfaces. of which are provided with dwell portions adapted to hold the heads at the twisting station until the twisting operation has been completed.

When the band 53 is disposed around the peach half at station B, pressurized fluid is directed into power cylinder 210 through the upper connection 213 causing the lever 205 to be pivoted clockwise (FIG. 1). Accordingly, the outer carrier 40 of head 10 is rotated clockwise and the outer carrier 40 of head 20 is rotated counterclockwise. During this movement of the outer carriers, the pins 80 (FIG. 3) of the inner carriers move radially inwardly in the guide slots 32 causing the band 53 of each head to be wrapped around the associated peach half. When the movement of the outer carrier has been completed, the sprockets 60 are rotated causing the inner carrier 42 of the head 10 to be rotated counterclockwise (FIG. 1) and the inner carrier 42 of head 20 to be rotated clockwise. As the inner carriers rotate, the outer carriers remain stationary until the bands have been tightly wrapped around the peach halves and the pulling forces on each band increases to a point where it overcomes the frictional resistance of each friction liner 101 to the reverse rotation of the associated shaft 92. When this resistance has been overcome, the shaft 92 of each outer carrier rotates in a reverse direction, carrying the attached plate 90 and pins 48 with it. Thus, when the outer carrier has completed its rotation, the bands have been wrapped around the peach halves with a tightness determined by the resistance of the friction liners.

When the peach halves have been twisted free from the pit, the

cylindrical cams

160 and 174 move the

heads

10 and 20 away from station B. Pressurized fluid is then directed into the lower connection 214 of power cylinder 210 causing the lever 205 to be pivoted counterclockwise (FIG. 1) whereby the outer carrier 40 of the twisting head 1% (FIG. 4) is rotated counterclockwise and the carrier 40 of head 2% is rotated clockwise to move the associated bands 53 to open position. As seen in FIG. 3, as the outer carrier as of head 10 is rotated counterclockwise, the carnming surfaces 91a and 91b move the pins 5d of the innner carrier to their outermost positions, to complete the movement of the band 53 to its fully open position.

It will be noted that the present invention provides a peach gripping and twisting mechanism that is capable of automatically varying the twisting torque applied to the peach in accordance with the maturity of the peach. It is evident that ripe peach halves may be twisted from their pit more easily than green peach halves. During the operation of the present twisting mechanism, the outer carrier is first rotated to bring the band into light frictional gripping engagement with the peach half. Thereafter, the only function of the outer carrier is to maintain the frictional engagement of the band with the peach half so that the torque required to twist the peach half from the pit can be applied to the peach half by reverse rotation of the inner carrier. Thus, as the inner carrier is rotated to the twist the peach half from the pit, torque is developed in an amount necessary to twist the peach half from the pit. If the peach is soft, the torque required to twist it will be low and, therefore, only a low torque will be developed. To produce this low torque, only a low force on the inner carrier and a correspondingly low radial pressure on the peach half is required. If the peach is green, a larger torque is required. Accordingly, a larger force will be exerted by the inner carrier with a correspondingly larger radial pressure on the peach half. Thus, the twisting device of the present invention accomplishes the twisting of a peach half while applying an amount of pressure to the peach that is dictated by the condition of maturity of the peach, in distinction to other twisting mechanisms which grip all peach halves with a predetermined pressure which must be large enough to grip the greenest peach being handled. Sinch ripe peaches cannot withstand much pressure without being damaged and, since the present twisting device applies a minimum amount of pressure to such peaches, it is evident that a minimum amount of damage to the peaches results when they are twisted by means of the twisting mechanism of the present invention.

It is evident that, while the outer carrier maintains the frictional engagement of the band with the peach. this carrier may be rotated in a reverse direction with the inner carrier during the twisting of the peach half from the pit.

While two twisting heads are shown operating simultaneously, it will be understood that each head may be operated separately to twist a peach half from a pit. Such an independently operable head is shown in the above-mentioned Drake et al. application.

It will be understood that modifications and variations of the fruit gripping members of the present invention may be made without departing from the scope of the novel concepts of the present invention.

Having thus described the invention, what is claimed as new and for which Letters Patent is desired is:

1. In combination in a twisting head, a support struc ture, a flexible band, means mounting said band on said structure for movement from an expanded position defining a loop adapted to receive a drupaceous fruit segment therein to a contracted position in engagement with the fruit segment, means for bisecting a fruit and gripping the pit, means for positioning a half of the bisected fruit within said loop, first power means connected to one end of said band and arranged to rotate said band to exert a pull on said band in a direction to move said band into frictional gripping engagement with the surface of the fruit half, and second power means connected to the other end of said band and arranged to apply a progressively increasing pull on said band to apply an increasing torque to the fruit half while said first power means maintains the frictional engagement of the band with the fruit half.

2. In a twisting head the combination of a support structure, a flexible band mounted on said support structure for rotary movement from an expanded position defining a loop adapted to receive a segment of a drupaceous fruit therein to a contracted position in engage ment with the fruit segment, means for bisecting a drupaceous fruit and gripping the pit, means for positioning one half of the fruit within said loop, means for rotating said band into frictional engagement with the outer surface of the fruit half, and means for apply- 7 ing a progressively increasing turning moment to said fruit half through said band while said band is held in engagement with the fruit half.

3. In a twisting head the combination of a support structure, a flexible band mounted on said support structure for rotary movement from an expanded position defining a loop adapted to receive a segment of a drupaceous fruit therein to a contracted position in engagement with the fruit segment, means for bisecting a drupaceous fruit and gripping the pit, means for positioning one half of the fruit within said loop, means for rotating said band in one direction into firictional engagement with the outer surface of the fruit half, and means for applying a pull on said band in a direction opposite to said one direction to apply a torque to the fruit half and a progressively increasing radial pressure on said fruit half.

4. In a twisting head for a pitting machine, the combination of an outer carrier mounted for rotation about a predetermined axis, a first pin secured to an outer peripheral portion of said carrier, an inner carrier having a guide groove directed radially inwardly toward said axis, a block slidable in said groove, a second pin carried by said block, a flexible strap having a first end portion connected to said first pin and a second end portion connected to said second pin, means for positioning an article to be gripped substantially on said axis, and means for rotating one of said carriers relative to the other in a direction to first tension said strap and then move the first end portion of said strap radially inwardly toward said axis to contact the article to be gripped and then Wrap the strap around the article.

5. In combination in a twisting head for a pitting machine, first and second support members mounted for rotation about a predetermined axis, a pair of outer connector members mounted in diametrically opposed relation on said first support member, a pair of inner diametrically opposed connector members carried on said second support members for radial movement, all of said connector members being initially disposed on a common diameter of said first support member, a band connected between each outer connector and the inner connector on the opposite side of said axis, a cam secured to said first support member and disposed in position to contact said inner connector members to control radial movement thereof upon relative rotation between said first and second support members, and means for effecting relative rotation between said first and second support members to cause said inner connectors and one end of said bands to be moved radially inwardly toward said axis to cause said bands to close around and grip a fruit positioned between said bands.

6. In a twisting head for a pitting machine, a first circular plate mounted for rotation about a predetermined axis, a first pin secured to and projecting in a generally perpendicular direction from an outer edge portion of said first plate, a second circular plate mounted for rotation about said axis, a second pin projecting from said second plate and mounted for movement relative to said plate toward and away from said axis, a cam secured to said first plate and disposed in position to engage said second pin to control radial movement of said pin, a flexible strap secured between said pins, and means for effecting relative movement of said plates whereby said strap is tensioned and said first pin is moved in a circular path and said second pin is moved radially inwardly toward said axis causing the portion of said strap between said pins to be moved inwardly toward said axis to encircle a fruit disposed substantially on said axis.

7. In a twisting head for a pitting machine, the combination of a first plate mounted for rotation about a predetermined axis, a first pin secured to and projecting outwardly from and in a direction generally perpendicular to an outer peripheral portion of said plate, a second plate having a guide groove directed in a radial direction toward said axis, a second pin slidably disposed in said guide groove, a flexible strap connected between said pins, and means for rotating said first plate to cause said first pin to be moved in a circular path to tension said strap and to cause said second pin to be moved radially inwardly toward said axis whereby the portion of said strap between said pins is moved inwardly toward said axis.

8. In a twisting head for a pitting machine, the combination of a first plate mounted for rotation about a predetermined axis, a first pin secured to and projecting outwardly from and in a direction generally perpendicular to said plate, a second plate having a guide groove directed in a radial direction toward said axis, a block slidable in said groove, a second pin carried by said block, spring means connected between said block and said second plate and arranged to urge said block to slide radially inwardly toward said axis, a flexible strap connected between said first and second pins, and means for rotating said first plate about said axis from a first position wherein said strap loosely encircles an article disposed at said axis and said second block is in its outermost position in said guide groove to a second position wherein said strap is tensioned and in contact with the article and said block is disposed inwardly of its outermost position.

9. In combination in a twisting head, a support structure, a flexible band, means mounting said band on said structure for movement from an expanded position defining a loop adapted to receive a fruit segment therein to a contracted position in engagement with the fruit segment, first power driven means in frictional driving engagement with said mounting means for applying a predetermined driving force on said mounting means for moving said band into frictional gripping engagement with the fruit segment, and second power driven means for applying a progressively increasing pull on said band for overcoming the frictional engagement and imparting movement between said first power driven means and said mounting means while said first power driven means maintains said band in frictional engagement with the fruit segment.

References Cited in the file of this patent UNITED STATES PATENTS 1,072,966 Matthew Sept. 9, 1913 2,631,884 Horinka Mar. 17, 1953 2,826,227 Perrelli et a1. Mar. 11, 1958 2,952,286 Harrer et al Sept. 13, 1960