US3276833A

US3276833A - Door mechanism

Info

Publication number: US3276833A
Application number: US441748A
Authority: US
Inventors: Eugene F Felstehausen
Original assignee: Brunswick Corp
Current assignee: Brunswick Corp
Priority date: 1965-03-22
Filing date: 1965-03-22
Publication date: 1966-10-04
Anticipated expiration: 1983-10-04

Description

Oct 4, 1966 E. F. FELsTEHAusEN 3,276,833

DOOR MECHANISM 9 Sheets-Sheet 1 Filed March 22, 1965 Oct, 4, 1966 E. F. FELSTEHAUSEN 3,276,833

DOOR MECHANISM Filed March 22, 1965 9 sheets-sheet 2 Oct. 4, 1966 E. F. FELSTEHAUSEN 3,276,833

DOOR MECHANI SM Filed March 22, 1965 9 Sheets-Sheet 3 Oct. 4, 1966 E. F. FELSTEHAUSEN 3,276,333

DOOR MECHANISM Filed March 22, 1965 9 Sheets-Sheet 4 Oct. 4, 1966 E, F. FELSTEHAUSEN 3,276,833

DOOR MECHANISM Filed March 22. 1965 9 Sheets-Sheet 5 Oct. 4, 1966 E. F. FELSTEHAUSEN DOOR MECHANI SM 9 Sheets-Sheet 6 Filed March 22, 1965 Oct. 4, 1966 Filed March 22. 1965 E. F. FELsTl-:HAUs-EN 3,2 76,833

DOOR MECHANISM 9 Sheets-Sheet '7 06f- 4, 1966 E. F. FELsTEHAUsr-:N 3,276,333

DOOR MECHANISM 9 Sheets-Sheet 8 Filed March 22, 1965 NNN 06t- 4, 1966 E. F. FELSTEHAUSEN 3,275,833

DOOR MECHANISM 9 Sheets-Sheet 9 Filed March 22, 1965 United States Patent 3,276,833 DOOR MECHANISM Eugene F. Felstehausen, Hoopeston, Ill., assignor to Brunswick Corporation, a corporation of Delaware Filed Mar. 22, 1965, Ser. No. 441,748 23 Claims. (Cl. 312-223) A more specific object is to provide a new and improved door mechanism of the character mentioned including a ball cradle extending rearwardly from a door panel, a pivoted lever pivotally supporting the rear of the cradle, a cam track alongside the cradle, and an arm on the cradle having a follower engaging the cam track so that movement o f the lever and the follower control the door position.

.Another object is to provide a new and improved door mechanism of the type described including means `for oscillating adrive lever for moving the door, including a yieldably extensible link adapted to yield during obstruction of door closing movement to prevent damage to the door or an obstacle in the path of the door.

`A further object is to provide in` a door mechanism of the character described, an adjustable cam mechanism controlling door movement in order to provide selectively for movement of the door to either of two open positions. It is also an object to provide a new andimproved door mechanism of the `type mentioned including means associated with the door and the cradle'for holding a bowling ball during movement of the door from a door open position to a near closed position.

An additional object is to provide a track on the inside of the door for rolling a ball forwardly and downwardly o the door when the door is in a generally horizontal open position.

These and other objects of the invention will 'become' more fully apparent from the following description taken in connection with the annexed drawings, wherein:

FIG. l is a front perspective view of a preferred emi bodiment of the invention; 4

FIG. 2 is. an exploded perspective view of Athe ball polisher housing with certain parts broken away for clarity of illustration;

FIG. 3 is an enlarged front elevational view of the ball polisher shownA in FIG. 1, with the front panel removed;

FIG. 4 is a left hand side elevational view of the ball polisher illustrated i-n FIG. 1 with the outer left hand side panel removed;

' FIG.A 5 is a righft hand side elevational view of the ball polisher illustrated in FIG. l with the outer right hand side panel removed;

YFIG. 6 is a fragmentary .along line 6-6 of FIG. 3;

FIG. 7 is a view taken generally along line 7-7 of FIG. 6;

FIG. 8 is a view similar to FIG. 6 and showing the door in the open positions;

FIG. 9 is a sectional view taken generally along line 9--9 of FIG. 7;

FIG. 10 is a fragmentary perspective view of the bung compound applicator, with certain parts being broken away vfor clarity of illustration.

sectional view taken generally 3,276,833v Patented Oct. 4, 1966 FCC.

FIGS. 11A and 11B are a schematic electrical circuit l `The present invention is primarily concerned with a bowling ball polishing machine which Vis adapted for use customers, as well as by the bowlingA The polishing machine includes a door` by bowling alley alley proprietor.

assembly which moves a bowling ball into the interior of the Apolishing machine, and holds the ball against a single buing wheel. Means are provided for selecting the duration of the bufng cycle, and coin operated control means are provided for customer use, while suitable switch means are provided for the polishing of house balls by the bowling alley proprietor. The present invention contemplates a machine wherein three different length butling cycles may be selected; namely, a two-minute cycle, a

live-minute cycle, and a ten minute cycle. The afore.

mentioned door structure for ,introducing a bowling ball i into the interior of the polishing machine is movable between a single closed, and two different open positions.

One ofthe open positions corresponds to customer opera- 4tion of the machine, Iand the other open position corre sponds to proprietor operation of the machine. In the door open position for customer use, the door structure is positioned so as to support a ball when `a ball is placed in the door structure by a customer.

discharging a ball from the machine, and a second location for automatically receiving a ball for introducing the same into the interior of the machine. The second door open position in the polishing of house balls corresponds to -the door open position for the polishing of customersballs. Thus, a ball polishing machine is provided which is well adapted for customer use, as well as for the automatic polishing of house balls, in that balls may be automatically fed into the machine for polishing thereof, and automatically expelled therefrom when the polishing cycle is completed.

Referring now to FIG. l, the ball polishing machine is illustrated in its entirety by reference numeral 20.

The ball polisher 20 includes a box-like housing or cabinet dened by spaced

side panels

21 and 22, a front panel 2'3,`a -top panel 24, and a rear frame member 25. Suitable mounting feet 26 are provided on lower. frame members 27 for supporting the housing on a suitable support surface, such as a floor. Y An illuminated control panel 28 provided adjacent the upper portion of front panel 23,

and at the forward end of top panel 24. A plurality of indicating lights 29 are provided on the control panel 28 for indicating the time remaining on the selected polishing cycle. Control panel 28 also includes a coin slot 30 for accepting suitable denomination coins to initiate the desired polishing cycles, a coinreject button 31, and a coin return slot 31a. A manually depressable start button 32 is provided adjacent the right hand end of control panel 28, Iand an indicating light 33 is provided adjacent thereto for indicating a sold out condition of the machine.

As can be best seen in FIG. 2, the ball polisher 20 in` cludes -an inner or sub-frame delined by spaced

side frame members

35 and 36, which are secured to the rear frame :member 25 and to the lower frame members 27. The upper ends of

side frame members

35 and 36 are bent outwardly at generallyrightvangles4 with respect thereto In the door open position for the polishing of house balls, the door struc-V ture is movable from a first location for automatically 3 at 35a and 36a respectively, and define therebetween a generally rectangularly shaped opening 37.

A first baliie member 38 is secured to rear frame member 25,` and extends forwardly therefrom in a horizontal plane generally perpendicul-arly to side frame members 35 and 36.` The forward end of baffle member 38 includes a downwardly extending, generally vertically disposed first portion 38a, and a downwardly inclined second portion 38h extends forwardly from the lower end of baille portion 38a. Baie 38 further includes a third portion 38e which is disposed in a generally horizontal pl-ane, vand extends forwardly from the lower edge of batlie portion 38b. A second baffle member 39 extends generally vertically upwardly from baii'le member 38, and divides the interior of the ball polisher housing into a first or ball compartment 40, and a second or bufiing compartment 41 rearwardly and upwardly therefrom. Baliie member 39 `has an opening 42 therein, for a purpose to hereafter appear.

As` can be seen in FIG. `6, a bufling wheel W is rotatably mounted in compartment 41, and a ball B is adapted to be held in compartment 40 by a door mechanism to be hereafter described. The ball B is adapted to extend into the compartment 41 through the opening 42 in baffle member 39, where it is held in engagement with the outer periphery of the bufiing wheel W by the door mechanism. A bar of buffing compound material C is also provided in compartment 41, and is adapted to be periodically moved into engagement with the periphery of the bufling wheel W by means to be hereafter described to apply a desired amount of buiiing compound material to the wheel W. The construction of the bufing wheel W is set forth in detail in the application filed concurrently herewith in the name of Otto E. F. Puhlmann under attorneys docket 1243-C.

A generally rectangular doorway 45 is provided in front panel 23, and a door assembly 46 normally closes the doorway 45, as can be seen in FIG. 6. Means are provided for opening the door assembly 46 so that a ball :may 'be introduced into the compartment 40, and includes a door motor assembly 47 held on the side frame member 36 as by bolts 48 and including .a motor 49 and a gear reducer unit 49a. The door drive motor 49 has a double ended shaft, including a first portion 50 which extends outwardly through the side frame member 36 for driving the door moving mechanism, and a second portion 51 which extends inwardly from the side frame member 36 for driving a timer cam means for controlling the sequence of operation of the door actuating mechanism.

The door assembly 46 includes a first 'door panel 52 having a cover plate 53 secured thereto and adapted to overlie the doorway 45 when the door assembly 46 is closed. Door member 52 is somewhat W-shaped in crosssection, as can be best seen in FIG. 9, and includes a pair of spaced generally parallel side walls 54 and 55,` downwardly extending

inclined walls

56 and 57 diverging inwardly from the upper ends of side walls 54 and 55, respectively, and a central wa-ll 58 generally perpendicular to side walls 54 and 55. Inclined `walls 55 and 56 cooperate with the central wall 58 to define a trackway for reception of -a bowling ball. Central portion 58 is provided with a generally rectangular opening 60, and a rotatably mounted cylindrical ball engaging roller 61 is positioned in the opening 60.- Roller 61 is carried by a pair of generally identical brackets 62 that are pivotally mounted to the door member 52 by a pivot member 63. Brackets 62 include an apertured enlarged portion '62a at the lower ends thereof, and a spring 64 is connected between the bracket portions 62a and the door to bias the roller 61 through the opening 60. A pair of switches 65 and 66 are mounted adjacent brackets 62, and a suitable cam member 67 is operatively associated with the brackets 62, for engaging the operating levers 65a and "66a of the switches 65 and 66 respectively. Thus, when a ball is present on the track of door member 52, the roller 61 4 will be depressed to pivot the brackets `62 and actuate the switches 65 and 66. Thus, roller 61 and switches 65 and 66 cooperate to define means for sensing the presence 0r absence of a bowling ball on the door assembly.

The door assembly 46 further includes a rearwardly extending cradlel assembly .defined by a pair of spaced

plates

70 and 71 each fixed `to door member 52 'as by bolts 73. A somewhat triangularly shaped plate 74 extends downwardly from cradle member 71 to effectively define a bell member, and a cam follower roller member 75 is fixed to the offset lower portion 74a of plate 74 `for tracking cam means to be hereafter described. A hollow sleeve 76 is fixedly secured adjacent the rearward end of cradle members` 70 and 71,@and defines a horizontal axis for rotation of a shaft 77 received ,in sleeve 76.- TWO spaced rubber rollers 78 are` rotatably mounted on each of -

cradle members

70 and 71, with the rollers'on cradle member 70 being aligned with the rollers oncradle member 71. The rollersr 78 cooperate to collectively define a cradle upon which the bowling bal-11B is adapted `to be seated when the door assembly is in a door open position.

, 'Ihe means for moving the aforedescribed door assembly 46 from the closed position shown in FIG. 6 to the open positions shown in FIG. 8 includes a crank 80 fixed to the shaft portion 50 of the door drive motor 49.` A pair of generally identical, T-shaped lcrank links 81 and 82 are held on crank 80, as by a screw 83.` Crank links 81 and 82 are provided with respective longitudinal-

ly extending slots

84 and 85 adjacent one end thereof, and circular openings 86 are provided in the crank links adjacent the other end thereof. As can be seen in FIG. 7, the crank arm extends outwardly through the circular opening 86 in crank link 81 and the longitudinal slot 85 in crank link 82; while a shaft 87 extends through the circular opening 86 in crank link 82 andthe longitudinal slot 84 in crank link 81.' Springs 88 and 89 are connected between the crosspieces of 4the T-shaped crank llinks 81 and 82 to urge the same toward one another, and to retain the end of crank arm 80 and the shaft 87 at the end of slots and 84. Thus, crank

links

81 and 82 cooperate to define a yieldably extensible connecting rod for crank 80. If a foreign object, such as a hand, is caught in the doorway during the door closing cycle, the links 81` and 82 will rmove relative to one another to prevent damage to the object. A switch 90 'is mounted on the outer side of frame member 36 adjacent shaft 87, and as will hereinafter be more fully explained, switch 90 is closed by downward motion of the shaft 87 when it is in the lowest position to provide a signal indicating the closed condition of the door structure.

Shaft 87 extends inwardly of the side .frame member 36 through a Vsuitable opening 91 therein, and a pivotally mounted generally triangularly shaped cover plate 92 is positioned in face abutting engagement with the inner surface of side frame member 36 to normally cover the opening 91. Cover Vplate 92 includes a first opening,`

which receives the shaft 87 therethrough, and a second opening adjacent the apex thereof which pivotally mounts the cover plate on transversely extending fixed shaft 93.`

As can be best seen in FIG. 3, shaft 93 extends completely across the polishing `machine housing between

side frame members

35 and 36, and suitable means, Ysuch as screws 94 (FIG. 7) are provided .to retain the. shaft 93` on the

side frame members

35 and 36.

A crank lever 95 is pivotally mounted on shaft 93, and is connected between shafts 77 and 87 for operation of the door assembly 46 from the closed position of FIG. 6 to the openv positions of FIG. 8. 'Ihe midportion of crank lever 95 includes a pair of spaced

journal members

96 and 97 which pivotally mount the crank lever 95 on the shaft 93. A suitable collar '98 Vis fixed on the shaft 93 to retain the crank lever 95 inthe desired position. Crank lever 95 includes an angulated upwardly extending portion 99, secured to the shaft 77 by a screw 101. Crank lever 95 further includes a downwardly extending 'bell crank which terminates in a sleeve 100 that is portion 102, which'is apertured for reception of shaft 87. A suitable lock nut 103 retains the bell crank portion 102 on shaft 87 against the bias of spring 104. Thus, it will be readily apparent that as the door motor shaft 50 rotates the crank 80, the connecting rod defined by crank

links

80 and 81 oscillates the crank lever 95 to move the door assembly 46 between the closed position shown in FIG. 6 and the open position shown in FIG. 8. Means are provided for controlling the open position to which the door is moved, and includes a cam 105 fixed adjacent the inner surface of side ame member 36 as by screws 106. Cam 105 includes a cut out central portion, which defines a pair of cam surfaces 107 and 108. Cam follower roller 75 rides along the cam surfaces of cam member 105 to control the open position of the door assembly, and suitable spacers 109 space the cam 105 from the side frame member 36 so that the cam follower roller 75 may move freely along the cam surfaces.

Means are provided for selecting which of the cam surfaces the cam follower roller 75 is to follow, and includes a movable cam member 110 fixed to a shaft 1'11 which is mounted in the frame member 36 for both pivotal and axial movement. A manually operable handle 112 is fixed to shaft 111 outside of frame member 36, and a spring 113 is connected between the handle 112 and a `suitable post on the frame member 36 to bias the handle 112 in a clockwise direction as viewed in FIG. 5. Spring 113 normally urges the cam 110 into the position shown in FIG. 6, where the arcuate cam surface 110a on the undersurface of cam 110 cooperates with the cam surface 107 on the cam 105 to dene a generally semicircular path of travel for cam follower roller 75. Shaft 111 is free to move transversely outwardly of side frame member 36, and springs 115 surround the shaft 111 and bear against collars fixed on the shaft 111 to urge the cam 110 axially into the position shown in FIG. 7. A first stop member 116 is fixed to t-he outer surface of cam 105, and functions to retain the cam member 110 in the solid line position shown at 110 in FIG. 8, against the bias of spring 113. A latch plate 116:1 is positioned to retain the cam 110 against axial movement. 0n pivoting cam 110 clockwise in FIG. 8 to clear latch plate 116a, the cam may be moved axially outwardly and released to move counterclockwise to the broken line position 110 in FIG. 8, resting against stop 116b on bolt 106. When the cam member is in the broken line position shown at 110 in FIG. 8, the cam follower roller 75 is free to move along the cam surface 108 upon oscillation of the crank lever 95 and the door may move to the open position shown in broken lines. It will be readily understood that when it is desired to move the door into the full line open position shown in FIG. 8, it is necessary merely to rotate handle 112 in a clockwise direction, and to push the handle inwardly toward frame member 36 to engage the cam member 110 with t-he latch members 116 and 116a whereupon the spring 113 will hold the cam member 110 in the position shown in FIG. 6.

Ascan be seen in FIG. 8,' when the cam surface 110a has been selected, the door assembly 46 is movable to the full line position where the cradle assembly and the door panel 52 are positioned entirely outwardly of the cabinet of the polishing machine, with the door panel 52 and the cradle assembly each being inclined upwardly and converging toward one another. The cam surface ln operation is selected for customer use of the polishing machine, and it will be readily apparent that a bowling ball placed upon the door panel52 will roll down the trackway thereon into engagement with the rollers 78 on the cradle assembly. As will hereafter be more fully explained in detail, the placement of a ball on the door panel member 52 pivots the roller 61 and brackets 62 to actuate the switches 65 and 66 for moving the door assembly to the closed position. When the cam surface 108 has been selected, the door assembly will move into the position shown generally in broken linesl in FIG. 8. In this position the door panel 52 is positioned generally horizontally, and the trackway thereon is inclined downwardly at a very small angle, as evidenced by the inclination of central portion 58' of the door panel 52. This position corresponds to the ball discharging position in automatic operation of the machine for polishing house balls, and it will be understood that due to the downward inclination of the door panel trackway, balls will roll ofi of the door structure onto a suitable support device. After the polished ball has been discharged from the machine, means to be hereafter described move the door assembly from the broken line position of FIG. 8 to the full line position of FIG. 8, Where the door assembly is in position for accepting an additional ball from the ball supporting device.

After the bowling ball B has been positioned in the door assembly 46, and the door assembly has Imoved into the closed position shown in FIG. 6, rotation of the bufiing wheel W is initiated to accomplish the polishing of the ball B. As can be best seen in FIGS. 3 and 4, a drive motor M is fixed on the frame by a suitable support structure S. The motor M has a double ended shaft, and one end extends outwardly through the side frame member 36. A pulley 146 is fixed on motor shaft portion 145, and an endless belt 147 is trained over the pulley 146, and over a pulley 148 fixed on a shaft 149 which is rotatably mounted in the side frame member 36. As can be best seen in FIG. 6, the butiing wheel W is fixed on shaft 149 for rotation therewith.

A drive system is positioned between side frame member 35 and side panel 22 for operating various mechanisms of the ball polishing machine to be later described. An endless belt 126 is trained over a small diameter pulley 127 fixed on the motor shaft portion 125 extending outwardly through side frame member 35, and over a large diameter pulley '128 fixed on a shaft 129 rotatably supported in side frame member 35 by suitable bearing means 130. A small diameter sprocket 131 is fixed to shaft 129, and an endless chain 1-32 is trained thereover,v

and over `a relatively large diameter sprocket 133 fixed to a shaft 134 rotatably mounted in side frame member 35. A very small diameter sprocket 135 is fixed to shaft 134, and an endless chain 136 is trained thereover, and over a relatively large diameter idler sprocket 137 that is `fixed to Ia shaft 138, which is rotatably mounted in the side frame member 3S. A small diameter sprocket,

139 is fixed to shaft 138, and an endless chain 140 is trained thereover, and over a relatively large diameter sprocket 141 that is fixed on a shaft 142 rotatably mounted in the side frame member 35.

Means are provided for creating relative movement between the`ball and the -bufling wheel W, and include a brake roller formed of rubber or the like, yand fixed on shaft 129. Roller 150 is positioned between the cradle rollers 78 (FIG. 3), and is adapted to engage the undersurface of a -bal-l carried by the door structure when the same is closed to lift the ball off of the cradle rollers. Because of the step Adown relationship between

pulleys

127 and 128, shaft 129 rotates at a speed substantially less than the speed of rotation of shaft 149. Thus, since the roller 150 is rotating at a slower speed than the buliing wheel W, the roller 150 serves as a brake, which impedes the rotation of the bowling ball B Vto thereby create relative movement between the bowling ball and the bufiing wheel. The relative movement between the bowling ball and the bufng wheel creates the polishing action on the ball. Y

A suitable metal roller 151 (FIG. 6) is rotatably mounted between a pair of brackets 152 that are secured to the bafiie member v38. Roller 151 extends upwardly into the bufling compartment 411, and is adapted to be when the door assembly 46 is closed the ball which has been placed on the track member 52 and the cradle rollers 78 will be .lifted out of engagement with the cradle roller 78 by the brake roller 150. The center of gravity of the bowling .ball is positioned slightly to the left of the pivotal axis 150 as viewed in FIG. 6, so that the ball is supported 'by the brake roller 150, and the metal roller 151 during the buing action, with the rollers 153 serving to prevent lateral movement .of the ball.

Means are provided for periodically twisting the bowling ball B so as to present new surfaces to the bufling wheel for polishing thereof, and includes a pair of segment shaped members 155 rotatable with a fore and aft extending horizontal shaft 156. Shaft 156 is disposed yat right angles with respect to shaft 134, and suitable worm gear means (not shown) in housing 157 connect the shaft 134 to the shaft 156 for rotation thereof. Rubber bumper members 158 are carried at the outer end of each of the segment members 155, and are adapted to engage the undersurface of the .bowling ball upon rotation of the shaft 156 to lift the bowling ball olf of its supports and move a new surface into engagement with the buing wheel W. Brush 159 lis mounted on shaft 156 between the segment shaped members 155, and is adapted to engage the brake roller 150 upon rotation of the shaft 156 to maintain the brake roller in a clean, grit free condition.

A forced air ventilation system is provided through the ball compartment 40 and the buing compartment 41 to insure that all dirt and dust is removed from the Iball during a polishing cyole. To this end, an irnpeller type Iblower wheel 160 is fixed to the outer end of motor shaft 145 and communicates with a scroll-like housing 161 for directing air upwardly through Ian elongated duct` 162 and into the ball compartment 40 through an opening 163 in side frame member 36. The ball compartment 40 is substantially air tight, so that the air introduced therein through opening 163 passes into the bufling compartment through the opening 42. The air ows past the bowling ball and the buiing wheel at a high velocity so as -to remove all dirt and dust from the ball. Air vents 165 are provided in the top panel 24 in communication with the buing compartment 41, and a suitable filter 164 is removably carried by the top panel 24 to remove impurities from the air passing outwardly from the machine.

Means are provided for periodically moving the buliing compound material C into engagement with the buling wheel W and for indexing the bung compoun-d material, and will be :best understood :from a consideration of FIGS. v3, 4 and 10. A pair of generally triangulanly shaped plates 170 are mounted in spaced relation to the side frame member 35 by bolts 171. A generally U- shaped driving housing 172 straddles the plates 170, and the rearward ends of the legs of housing 172 are pivotal- 'ly mounted on the uppermost rear bolt '171. A spring 173 is connected between the housing 172 and the forwardmost bolt 171 to .bias the housing 172 downwardly toward the -buing wheel. A shaft 175 is rotatably mounted on the legs of the housing 172, and extends into the bufling compartment through a suitable opening -in side frame member 35. The butiing compound material is keyed to the inner end of shaft 175 by means of a drive hub 176 fixed on the shaft 175 and having a drive pin 177 positionable in the compound material. A spiral spring 176a surrounds shaft 175, and bears against hu-b 176 to force the compound against a collar 177a fixed to the end of shaft 175. The compound material is initially a generally cylindrically shaped member, which has an arcuate cut out or recess portion 178 extending the length thereof. The curvature of arcuate portion 178 is convex axially to correspond generally to the axially concave outer periphery of the bufiing Wheel W, so that when the compound C is moved into engagement 8 with the bufling wheel, compound will be generally uniformly applied to the wheel.

Means are provided for rotating the shaft at a very slow speed so that the compound material C will be indexed slowly. It will be readily appreciated that after the shaft 17-5 has rotated through approximately 270 the compound material remaining on the shaft 175 will have the shape shown at C in FIG. 10. Thus, by indexing the compound material, substantially all of the same is used in applying compound to the bufling wheel. The means for rotating the shaft 175 at the desired speed includes a reduction lgearing system 179 nested between the arms of the U-shaped drive housing 172. The reduction gearing system 179 .iinoludes an output gear 180 fixed on shaft 175 for rotation thereof. A series of'relatively large diameter gears 181 (three in the illustrated embodiment) are rotatably mounted on each of the yaxes defined by the uppermost rear bolt 171 and shaft 142. Each of gears 181 is a compound gear, and has a small diameter pinion 182 formed integrally therewith, and

the gears 181 on bolt 171 each mesh witha pinion 182 on shaft 142, while the gears 181 on shaft 142 each mesh with a pinion 182 on bolt 171'. The last gear 181 on bolt 171 engages gear 180 to rotate the same. A cam 185 is mounted on shaft 142 and is coupled to sprocket 141 for rotation therewith. Thus, the shaft 142 is rotated :by the action of chain 140-on sprocket 141, Vand this rotational speed is stepped down through the reduction gears 181 and pinions 182 to impart the desired slow output rotational speed to the gear 180. Cam 185 engages a cam follower 186 that is provided on shaft 175 for periodically allowing the spring 173 to move the compound material C into engagement with buing wheel W. Cam 185 rotates at approximately one rpm., and is shaped so as to lal-low the compound material C` to engage the butiing wheel W once each minute of polishing operation and for approximately 30 of cam rotation.

A switch 187 is mounted on the outer triangular plate 170, and a `pair of bolt heads 189 is provided on `the sprocket 141 for actuating switch 187. The actuating lever for the switch 187 projects inwardly through a suitable opening 191 in the outer plate 170 where it is positioned in -the path of travel of bolt head 189. Since cam 185 and sprocket 141 rotate at approximately one r.p.m., it will be readily apparent that switch 187 gives a signal once each minute during a polishing operation. A sold out switch 193 is mounted on the U-shaped drive housing 172, and is adapted to be closed by a cam profile 194 on the hub of gear 180 when the gear 180 has made a complete revolution to indicate that the supply of compound material has been exhausted.

Cam means 200 are mounted on the door motor shaft 51 for operation of a bank of switches 201 to control the sequence of operation of the door assembly 46.. The cam means 200 includes six cams 202207,` and six switches 208-213 are provided in switch bank 201 for respective operation by the cams. Switch 208 is 4controlled by cam 202 which has a low dwell from 355 to 15 of each door cycle. Switch 208 is therefore closed during each door cycle from 355 to 15 and is open between 15 and 355 of each ball door cycle. Switch 209 is controlled by cam 203 which has two low dwells, one occurring between 5 and 25 and the other occurring between and 210. Switch 209 is unactuated during each ball door cycle between 5 and 25 and again between 190 and 210. Switch 209 is actuated at all other times during the ball door cycle. Switch 210 is a two position switch and is controlled by cam 204.1 Cam 204 has an extended low dwell from 300 through 180,and thus switch 210 is in one position from 300 to 180, 4and in its other position between 180 and 300. Switch 211 is a two position switch, and is controlled by cam 205. Cam 205 has an extended low dwell from 320 through 175, and therefore switch 211 is in one position from 320 to 175, and in its other position between 175 and 320. Switch 212 is an open-close switch which is controlled by cam 206. Cam 206 has an extended low dwell from 290 to 240 of each ball door cycle, so that the switch 212 remains open from 290 to 240, and closes between 240 and 290. Switch 213 is an open-close switch that is controlled by cam 207, which has an extended low dwell from 310 to 260 of each ball door cycle. Switch 213 therefore closes during each ball door cycle between 310 from 260 to 310.

An electrical control box 215 is mounted on side frame member 36, and a rotary stepping switch 216 is mounted therein. The rotary stepping switch includes three banks of contacts 216:1, 216b, and 216C each arranged in an arc of a circle. Each bank of contacts has eleven points, which are contacted respectively by wipers 21711, 217b, and 217e as the wipers rotate through a mechanical ratchet and coil mechanism. The top bank of contacts 216a are each connected to the 10 individual indicating lights 29 on the control panel. As the wiper 217a advances one postion per minute, the remaining minutes in the ball polishing cycle are indicated to the customer by the lights on the control panel. The middle bank 216b of the rotary step switch is utilized to control the timing mechanism for a two minute polishing cycle. When the proper amount of money is deposited in the coin slot 30 to obtain a two minute cycle, an interrupter, to be hereafter described, causes the wiper 217b to step off the contacts until it reaches the first open position, where it stops to make a two minute cycle. The `bottom bank 216e of the rotary stepping switch is utilized to obtain a ve minute polishing cycle, and operates in a manner similar to theV middle bank of contacts. The rotary stepping switch 216 is operated by a coil 218, which when energized, pulls down on the ratchet lever of the stepping switch, thus causing the wiper to advance one position.

' An interrupter switch 219 is connected in series with the stepping coil 218, and when voltage is applied through the interrupter switch contacts, the coil 218 becomes energized to pull down on the ratchet and rotate the wiper one position. As the ratchet is pulled down, the circuit to the interrupter is broken and removes switch coil 218. The ratchet mechanism then moves upwardly and advances the wiper one position on the rotary stepping switch 216, and simultaneously closes the contacts of the interrupter switch 219 to again energize the coil 218. This action continues until the wiper 217 reaches the first open contact. set for the proper time cycle.

A A coin switch 224 is operably lresponsive to the deposit of an appropriate number of coins in the coin deposit slot 30, and includes a movable Wiperarm 225 which moves between a dead contact 226, a contact 227 for a two' minute polishing cycle, a contact 228 fora five minute polishing cycle, and a contact 229 for a ten minute polishing cycle. A bank of house ball switches 220-223 is mounted on the control box 215, and switches 220, 221 and 222 are connected in parallel with coin switch 224 and are used by 'the bowling alley proprietor to select cycles of two, five and ten minutes duration respectively, for the polishing of house balls. House ball switch 223 is an on-ott switch which remains olf during normalV customer operation, and is used only during house ball polishing operation.

The operation of the ball polishing machine will be best understood from a consideration of FIGS. 11A and 11B. During customer Vuse of the machine, a specic number of coin-s are deposited in the coin slot 30,- to select a polishing cycle. The control system for the machine includes a first master control switch 230, and a second master control switch 231. Switch 231 is a two position switch that is controlled by a cam on -the wiper 217 of the stepper switch 216. Switch 231 includes closed contacts 231a in a line 232 that is connected between switch 208 and lead L1A by a line 234, and open contacts 231b in a and 260, and is open current from the rotary The ball lpolisher is` then line 233 that is connected between lead L1 and door switch 66. A coin rejector coil 236 is connected in series with switch 208 in a line 237 that is connected to lead L2 through line 238. The coil 236 operates a conventional coil rejectermechanism which accepts coins when the coil is energized and which rejects coins when the coil is deenergized. Since switch 208 is closed during each door cycle from 355 to 15, the coin mechanism will only accept coins deposited during this portion of the cycle. Thus, assuming that the switch 208 is closed, and that the appropriate number of coins have been accumu lated by the coin mechanism for selection of a two minute polishing cycle, the wiper arm will move from contact 226 to contact 227.

AMaster control switch 230 isalso a two-position switch, and is controlled directly by the same cam action as master control switch 231. Switch 230 includes normally closed contacts 230a in a line 240 and normally closed contacts 230b in a line 241. A line 242 connects the -switch 230 with the house ball switch 223, and line 240 connects the closed contacts 230a with house ball switch 222 while line 241 connects the open contacts 230b in circuit with the start button 32. Switch 209 is connected to lead L1 by a line 243, and contact 209a of switch 209 is connected in a line 244, while contact 209b of switch 209 is connected by a line 245 to line 241. Push button 32 is connected to the wiper 217 of the rotary stepping switch by a line 247, and it will be readily understood that prior to thedepressing of the start button 32, no current ows to the wiper 217. When the start button 32 is depressed, a circuit is completed to the wiper 217 through lead L1, line 243, switch 209,'

line 245, line 241, and line 247.

Lines

248 and 249 respectively connect the wipers 217b and 217e with the

respective contacts

227 and 228 in the coin switch 224, while a line 250 connects line 240 to the contact 229 of the coin switch 224., Thus, when the appropriate number of coins have been deposited to select a two-minute cycle, and the start button 32 is depressed, a circuit will be completed to the interrupter switch 219 through line 248, contact 227 of coin'switch 224, and a line 251 connected to the line 252 in which the interrupter switch 219 is provided. iThus, a circuit is completed to the stepping coil 218 in line 253 through ar rectifier 254, which is connected between lead L2 and line 255. The. rectifier 254 changes the 11S-volt alternating current source connected across leads L1 and L2 to direct current for the stepping coil 218. The energization of stepping coil 218 causes the ratchet mechanism of the stepping switch to rotate the wiper 217 olf of its home position to the first contact, vwhich movement .actuates master control switches 230 andv 231 to their alternate positions. Master control switch'231 will retainthe stepping coil 218 energized after the push button 32`is released. .The rotary stepping switch 216 will then step until it reaches the first open contact to establish the duration for the po1` ishing cycle. Simultaneously, current will ow through' lead L1, line 234, contact 231b, line 233, switch 66, contact 66a, line 260, switch 211, line 261, and line 262 to energize the door motor 47. When the door motor becomes energized, the ball door mechanism starts the ball door in its opening motion to accept a ball. The door continues to open until switch 211 changes position at 175 from contact 211a to contact 211b. When the door motor rotates through 25, the switch 209 closes into engagement with contact 209a, so that a circuit is completed to the drive motor 47 through lead L1, line 243, switch 209, contact 209a, line 244, switch 223, line 263, and line 262 to retain the door motor energized even after the switch 211 moves into engagement with contact 211b. At of rotation, the switch 209 opens to deenergize the motor 47 and the door assembly 46 remains open awaiting a ball.

When a customer places a ball on the ball door cradle,\v switches 65 and 66 are actuated, land a circuit is com 225 of coin switch 224 Y switch V187 is pleted to the door motor 47 through lead L1, line 234, contact 231b, line 233, switch 66, switch contact 66b, line 265, contact 211b, switch 211, line 261, and line 262. The door motor then begins to move to the closed position, and at 210 the switch 209 moves into engagement with the contact 209a to retain the door motor energized when the switch 211 moves from contact 211b to contact 211a at 320. The door motor continues to rotate to a 5 position at which time switch 209 moves into engagement with contact 209b to interrupt the circuit to the door motor. At that time the door assembly 46 is in the closedv position shown in FIG. 6, with the ball therein positioned against the bufng wheel W.

When the door assembly reaches its fully closed position at 5, a circuit is completed to a bulring motor relay 270 through lead L1, line 234, contact 23117, line 233,

switch 66, contact 66b, line 268, switch 90, and line 269. Relay 270 includes a rst pair of normally open motor start contacts in a line 271 that are connected to the motor M through line 272, and a second pair-of normally open motor start contacts 270b in a line 273 which is connected to the motor M. Relay 270 further includes a pair of normally closed brake contacts 270e in a line 274 which is connected between line 271 and the motor M. Thus, when the relay 270 is energized, contacts `270a and 270b close to place the buing motor M across the 11S-volt power line to rotate the bufng wheel W and start the polishing cycle.

As the ball is being polished by the buing wheel, the compound applicator mechanism moves the compound material C against the buing wheel W one time per minute. Each time the compound material C is moved against the bung wheel W, the Vcompound applicator closed, which allows current to flow to the coil 218, thereby advancing the wipers of the stepping switch 216 to the next set of contacts. This action occurs one time during each minute of operation until the wipers pass the last contact position, at which time the wipers reposition themselves in the home position. As the wipers reach the home position, the master control switches 230 'and k231 return to their original positions, thus deenergizing the bui-ling motor relay coil 270. Relay contacts 270e` are then closed and act as a brake on the bung motor M.

At the rcompletion of the bufling cycle, it is necessary to open the door assembly to present the polished ball to the customer, and to then close the door assembly to await the next customer. With switch 231 in its original position, a circuit 4is completed to the door motor 47 through lead L1, line 234, contacts 231a, line 232,` line 280, door switch 65, contact 65a, line 281, switch 210, line 282, house ball switch 223, line 263, and line 262. The door motor continues to rotate to 190 even though the switch 210 changes positions at 180, since the switch 209 remains in engagement with contact 209a until 190, at which time switch 209 moves into engagement with contact '209b to stop the door motor 47. The customer then removes the .polished ball from the ball door cradle, and door switches 65 and 66 move into 'engagement with

contacts

65a and 66a respectively. The door motor 47 is then energized through a circuit including lead L1, line 234, contact 231a, line 232, line 280, switch 65, contact 65a, line 300, switch 210, line 282, switch-223, line 263, and line 262. The door mechanism will move to a completely closed position at 5 even though switch 210 changes positions at 300, since the switch 209 remains in engagement with contact 209a until 5. At that time the Vswitch 209 moves into engagement with the contact 209b to stop the door motor 47 with .the door completely closed and waiting the next customer.

In the example discussed above, a two-minute cycle was used to describe the electrical sequence. If however a tive minute cycle had been selected by the cus temer, .the deposited coins would have moved coin switch the door assembly arm 225 into engagement with contact 228, would have allowed a tive minute polishing cycle position the wipers in their home position.

and this to again If a ten minute cycle had been selected, the coin switch arm 225 would have been moved into engagement with the con tact 229, and the interrupter 219 would only advance the rotary stepping switch one position from home The rotary stepping switch would then require a ten minute cycle to again position the wipers at their home posia tion. The top bank of contacts 216a indicates the remaining minutes of each cycle to the customer by the indicator lamps 29 on the control panel.

Means are provided for illuminating the control panel 28 and includes a uorescent `lamp 290 connected in circuit with a starter 291 `and a ballast 292 in a line 238 that extends between leads L1 and L2. The sold `ou 7 switch 193 is connected by a line 294 to the sold out lamp 33, and as explained above, switch 193 is closed in response rto the bung compound material C being exhausted.

When the above described machine is to be used by the bowling alley proprietor -in polishing house balls, the movable cam is moved to the latched position shown at 110 in FIG. 8 by moving the handle 112, so that the cam follower roller 75 ytracks along cam surface 108. The house ball switch 223 is then closed, and one of switches 2204222 is closed to establish t-he desired duration Ifor the polish-ing cycle. When house ball switch 223 is closed, current will immediately ow through lead L1, line 234, master control switch contact 231a,.line 232, line 280, line 290, sold out switch 193, contact 193a, line 295, switch 213, line 296, contact 223b, `switch 223, l-ine 263, and line 262 to energize the door motor 47. The ball door mechanism will open to its furthest position; land then start its closing motion, and at 260 switch 213 opens to break the circuit `to the motor 47 and stop the motion of the ball door mechanism in its ball receiving position. As the rst ball is delivered to the ball door, the ball will actuate ball door switches 65 -and 66 to complete a circuit to stepping coil 218 through the selected one of house ball switches 220-222,.lead L1, line 234, contact 23111, line 232, line 280, switch 65, contact 65a, line 299, switch 212 (closed at 240), line 298, switch 223, and either one of lines 242 or 247.

The wipers will advance one step and the contact 231:1

` will open deenergizing coil 218. The stepping switch is thus set for a ten minute cycle. If a two or tive minute cycle has been selected the stepping switch will be positioned at 5 when power is available to the coil 218 from L1, line 243, switch 209, contact 209b, line 245, line 241, contact 230b, line 242, line 247 Iand either (1) wiper 217b 21'6b, line 248, line 301, switch 220, or (2) line 302, wiper 217e, segment 216C, line 249, line 303, switch 221; to line 252, stepper switch 219,line 255, rectifier 254, and coil 218. The rotary stepping switch wiper 217 will advance, thus actuating master control switches 230 and 231 to their alternate positions. When master control switch 231 moves to its alternate position, current immediately flows from lead L1 to the door motor 47 through line 234, contact 231b, line 233, switch 66, contact 66h, line 265, contact 211b, switch 211, line 261, and line 262. The ball door mechanism then completely closes .the ball door, and the closing motion of the door does not stop at 320 when switch 21'1 moves into engagement with contact 211a, because current ows through switch 209, contact 209a, line 244, line 282, contact223a, switch 223, line 263, and line 262 ,to the motor 47. The ball door stops at 5 when Ithe switch 209 returns -to its open position. Wit-h the ball door closed, current passes from lead L1, line 234,.contact231b, line 233, switch 66, contact 6611, line 265, line 268, switch 90, and line 269 to energize the boiling motor relay 270 andl energize the bui`n`ng motor to start the polishing cyc e.

The polishing cycle continues until the wipers of the 13 rotary stepping switch 216 reach their home positions, as previously explained, at which time master-

control switches

230 and 231 return to their original positions. Current then passes through lead L1,.line 234, contact 231a, line 232, line 280, line 290, switch 193, contact 193:1, line 295, switch 213, line 296, contact 223b, switch 223, line 263, and line 262 t-o energize the ball door motor 47 and open the ball door. As the door motor rotates 290, the door opens far enough to permit the polished Iball to roll from the ball door panel 52 on-to the supporting structure, and the discharge of the polished ball actuates switches 65 and 66. The motion of the ball door does not stop at 190, but continues until switch 213 isopened at 260. The ball door remains open at 260 until the next ball is automatically delivered on-to the door cradle structure, at which time the entire process is then repeated until all balls have been polished and delivered -to the ball supporting structure. At the completion of house ball operation, the selected one of house ball switches 220-222, and house ball switch 223 are moved to their own positions. Current then flows through lead L1, line 234, contact 231a, line 232, line 280, switch 65, contact 65a, line 300, switch 210, line 282, switch 223, line 263, and line 262 to energize the door motor 47 for closing the door. The door mechanism does not stop when switch 210 changes positions at 300 and continues to close until switch 209 opens at 5. The movable cam member 110 is then actuated by handle 112 to again prepare the machine for customer use.

I claim:

1. A door mechanism, comprising, a door panel adapted to be moved relative to a door opening between door closed and door open positions, a mounting arm on the panel extending -away from the panel, a lshaft pivotally supporting the end of the mounting arm, a lever having a portion pivotally mounted and a portion carrying said shaft, cam means adjacent the arm, -a cam follower on the arm engaging said cam means so that movement of the lever and the cam follower control the position of the door, and means connected to the lever for oscillating the latter back and forth between door closed and door open positions.

2. A combination as defined in claim 1, wherein the last recited means comprises a drive motor, a crank arm connected to be driven by the motor, and a connecting rod having one end pivotally connected to the crank arm and the other end pivotally connected to the lever for oscillating the same.

3. A combination as defined .in claim 2, wherein the connecting rod comprises a yieldably extensible link means normally retracted to a fixed minimum length and yieldably extensible during movement of the door panel toward closed position, thereby to prevent damage to the door panel and any obstacle in the path of the door panel preventing movement to door closed position.

4. A combination as defined in claim 3, wherein said yieldably extensible link comprises a pair of elongate plates slidably engaged with each other, one having one end pivotally connected to the crank arm and the opposite end slidably and pivotally connected to said lever, and the other having one end pivotally connected to said lever and the other end pivotally and slidably Vconnected to the crank arm, and spring means having opposite ends connected respectively to said one end of said one plate and said one end of said other plate and urging said one ends toward each other, whereby the length of Ithe link is extensible when the crank arm pulls the link.

5. A combination as defined in claim 2, :including means for controlling t-he drive motor to stop the latter with the door at door closed and door open positions.

6. A door mechanism, comprising a door panel adapted to be -moved relative to an upright door opening between an upright door closed position and a door open position, a rst bell crank on the panel extending rearwardly therefrom, -a shaft pivotallysupporting the bell Ycrank at a mid portion thereof, a second bell crank having a mid portion pivotally mounted and one end carrying said shaft, cam means adjacent the end of the first bell crank, a cam follower on4 the end of the first bell crank engaging said cam means so that movement of the second bell crank and the cam follower control the position of the door, and means connected to the other end of the second bell crank for oscillating the latter back and forth between door closed and door open positions.

7. In a cabinet structure having .a front opening, a door panel adapted to be moved relative to the opening between a generally upright door closed position and a door open position, a pair lof mounting arms on the door panel extending rearwardly therefrom adjacent a lower portion of the panel, a carrier pivotally supporting the ends of the mounting arms remote from the panel, a lever pivotally mounted on the cabinet structure and having an end portion supporting said carrier, cam means adjacent one of said mounting arms, a cam follower on said one arm engaging said means whereby movement of the lever and the cam follower effects movement of the door between door closed and door open positions, and means connected to the lever for oscillating the latter back and forth between door closed and door open positions.

8. A combination as defined in claim 7 including means on the mounting arms defining .a cradle structure for supporting a bowling ball or the like as the door panel approaches closed position.

9. A combination as defined in claim 8 wherein the cradle structure comprises two pairs of rollers on parallel axes, the rollers of each pair being coaxial and mounted respectively one on each arm.

10. A combination as in claim 7 including means on said mounting arms and said door panel defining a cradle structure for supporting a bowling ball or the like when the door panel is in open position.

11. A combination as in claim 7 including means providing a track on the door panel for rolling a bowling ball or the like forwardly and downwardly off the panel when the panel is in a generally horizontal open position.

12. In a bowling ball polisher cabinet structure having a front opening, a door adapted to be moved relative to the `opening between door closed and door open positions, a rearwardly extending ball cradle on a lower portion of the door, a lever pivotally mounted on the cabinet structure and having an end portion pivotally supporting a rear portion of said cradle, cam means alongside the path of movement of said lever end portion, an arm depending from said cradle and having a cam follower engaging said cam means so that movement of the lever and the cam follower effects movement of the door between door closed and door open positions.

13. A combination -as defined in claim 12, including means in the path of the ball cradle for assuming support of a ball from said cradle when the door is closed.

14. A combination .as defined in claim 1, including means for adjusting said cam means selectively to cause movement of the door panel to different door open positions.

15. A combination as defined in claim 12, wherein said cam means is adjustable to vary the door open position.

16. A combination as -defined in claim 15, 4said cam means comprising a first cam track engageable by said follower and having a shape causing movement of the door to a door open position in which the door is generally horizontally disposed, a second cam track engageable by said follower having a shape causing movement of the door to a door open position in which the door is inclined forwardly and upwardly, and means for selectively causing engagement of the follower with one or the other cam track.

17. A combination as defined in claim 16 wherein said last recited means comprises a pivotal support for one of the cam tracks, and means for moving said one cam track into and out of the path of the follower.

18. A combination as defined in claim liincluding a track on the door for rolling a ball forwardly and downwardly ol the door -in the generally horizontal open position.

19. A combination as defined in claim 16, including means on the door and on the cradle for supporting a ball when the door is in the inclined open position.

20. A combination as delined in claim 12 including means on the door and cradle for supporting a bowling ball during movement of the door from an open position to a near closed position.

21. In a bowling ball polisher cabinet structure having -a front opening, a door adapted to be moved relative to the opening between door closed and door open positions, a rearwardly extending ball cradle on a lower portion of the door, a bell crank lever pivotally mounted on the cabinet structure and having one end pivotally supporting a rear portion of said cradle, cam means alongside the path of said lever end, an arm depending from said cradle and having a cam follower engaging said cam means so that movement of the lever and the cam follower elects movement of the door between door closed and door open positions, a drive motor, a crank arm connected to be driven by the motor, a yieldably extensible connecting rod connected between the crank arm and the other end of the bell crank lever for oscillating the latter back and forth between door closed and door open positions, means for controlling the drive motor to stop the latter with the door at door closed and door open positions, rollers on said cradle for supporting a bowl-ing ball as the door approaches closed position, said cam means comprising a first cam track engageable by said follower and having Ia shape causing movement of the door to a door open position in which the door is generally horizontally disposed, a second cam track engageable by said follower hav-ing a shape causing movement of the door to a door open position in which the door is inclined forwardly and upwardly, and means for selectively causing engagement of the follower with one Ior the other cam track, Ia track on the door for rolling a ball forwardly and downwardly off the kdoor in the generally horizontal open position, and -rneans on the door and on the cradle for lsupporting a ball when the door is in the inclined open position.

22. In a bowling ball polisher cabinet structure having a front opening, a rotary polishing wheel inside the cabinet structure, a door adapted t-o close said opening, means mounting the door for movement relative to the opening between door closed and door open positions, means on the door for supporting the ball in the door open position, a ball cradle extending generally perpendicularly to the rear edge of the door, means on the door and cradle for supporting a bowling ball and transporting the same during movement of the door from an open position to a near closed position, and means in the path of the ball for assuming support of the ball when the door is closed.

23. A combination as defined -in claim 22, wherein the last recited -means supports the ball alongside the polishing wheel, and .including means on the door for holding the ball against the polishing wheel.

References Cited by the Examiner i UNITED STATES PATENTS 2,321,162 6/1943 Sohm 15-21 2,845,299 7/ 1958 Pickering 268--74 X 2,912,237 11/1959 Snyder 268--74 FOREIGN PATENTS 420,201 11/ 1934 Great Britain.

CLAUDE A. LE ROY, Primary Examiner.

F. DOMOTOR, Assistant Examiner.

Claims

1. A DOOR MECHANISM, COMPRISING, A DOOR PANEL ADAPTED TO BE MOVED RELATIVE TO A DOOR OPENING BETWEEN DOOR CLOSED AND DOOR OPEN POSITIONS, A MOUNTING ARM ON THE PANEL EXTENDING AWAY FROM THE PANEL, A SHAFT PIVOTALLY SUPPORTING THE END OF THE MOUNTING ARM, A LEVER HAVING A PORTION PIVOTALLY MOUNTED AND A PORTION CARRYING SAID SHAFT, CAM MEANS ADJACENT THE ARM, A CAM FOLLOWER ON THE CAM ENGAGING SAID CAM MEANS SO THAT MOVEMENT OF THE LEVER AND THE CAM FOLLOWER CONTROL THE POSITION OF THE DOOR, AND MEANS CONNECTED TO THE LEVER FOR OSCILLATING THE LATTER BACK AND FORTH BETWEEN DOOR CLOSED AND DOOR OPEN POSITIONS.