Door-Operating Mechanism

This invention relates to a door-operating mechanism. In particular, the invention is concerned with such a mechanism as applied to a door for a rotating drum in which products are processed. The processing of products in such rotatable drums usually is effected with the drum mounted on an axis inclined to the horizontal.

These drums normally have vanes or flights which can form a helical spiral on the inside wall of the drum for processing the products therein. Products processed in such drums include food pieces, in the forms of chunks of meat as is known in pending U.S. application Ser. No. 196,876, filed by Bruce Gould and assigned to the same assignee as this application; aggregate materials such as concrete, as illustrated in U.S. Pat. No. 3,175,811; or sheet materials in the form of hides, as is illustrated in U.S. Pat. No. 3,665,735. The disclosures in this application and the U.S. patents are incorporated by reference herein.

In U.S. application Ser. No. 196,876, there is disclosed a processor wherein an inclined drum includes a door for closing the mouth of the drum and through which a vacuum can be drawn in the drum. With such a vacuum, processing of the food products is enhanced. In this apparatus the door is mounted on a support structure which is part of the foundation supporting the drum. Despite the correct alignment of the drum and door when the apparatus is new, it has been found that due to wear, for instance, of the rollers on which the drum is supported or due to manufacturing tolerance characteristics, a misalignment can take place between the mouth of the drum and the door which is used to close the drum mouth.

As it is important for this closure to be tight, so as to enable a suitable vacuum to be drawn, it has been found that the operating characteristics of the drum of U.S. application Ser. No. 196,876 are not as efficient as desirable. In view of this misalignment undue stress is placed on the drum mounting mechanism, and particularly the hinge formation of the door operating mechanism which is an extended part of the structure from the foundation on which the drum rests.

In view of the above, there is a need to provide a door-operating mechanism wherein a moveable container and the door to the mouth of the container are permitted to be aligned so as to minimize the misalignment due to wear or otherwise normal manufacturing tolerances, and prevent deterioration of the hinged support mounting for the door, and other deleterious effect on the support means of the door operating mechanism. There is also a need to provide means for adjusting the relative position of the door with the drum, preferably in a facile manner, so that effective sealing of the door with the drum mouth can be achieved.

A door operating mechanism for a door to the mouth of a rotatable drum includes clamp means to releasably engage and disengage with a protruding shaft from the face of the door. There is an arcuately moveable arm mounted about anchoring means hinged on a support located adjacent the drum. The support is mounted on an extension of the foundation on which the rotating drum is mounted. The clamp means is mounted at the end of the moveable arm and is adapted to securely engage the door shaft until a predetermined vacuum pressure which is drawn in the drum, closed by the door, is reached. Release of the clamping means thereupon permits the door and drum to rotate integrally without imparting stress or force on the anchorage for the door.

When the vacuum is released and the pressure of the vacuum decreases towards atmosphere pressure, there is a movement effected by the arm axially relative to the rotating axis of the drum and away from the door. There is also a time delay prior to the clamp means again engaging the door shaft.

The mechanism includes a door swing cylinder for operating the moveable arm, and cylinders are provided for operating the clamping means. Vacuum sensing switches are operable with the cylinders and there is switching circuitry to effect a predetermined sequential operation of the cylinders of the mechanism relative to the vacuum pressure in the drum.

Adjustment bolts are provided about the hinged anchorage support so that the moveable means through its hinge pin can be adjusted transversely and axially relative the rotational axis of the drum. The door can thus be adjusted relative to the drum mouth to adapt for manufacturing tolerances and misalignment due to wear as the drum rotates on its foundation.

FIG. 1 is an end view of a door-operating mechanism for the door of a rotatable drum with portion of the hinged anchorage for the mechanism being shown in section, and also showing the cylinders for operating clamp means of the mechanism;

FIG. 2 is a side view of the door-operating mechanism showing a partial view of the door, a door swing cylinder and piston for the moveable arm together with solenoid vacuum valves for operating the door swing cylinder and cylinders of the clamp means;

FIG. 3 is a top view of the door-operating mechanism illustrating portion of the rotating drum, the door in abutment over the mouth of the drum, the moveable arm, the door swing cylinder laterally located on the support means adjacent the rotating drum, and also showing in phantom lines the door in the open position; and

FIG. 4 is a schematic of the electrical wiring for operating the anchoring means, moveable means, clamp means, vacuum generating pump and drum rotation.

A door-operating mechansim for a door 10 to the mouth 11 of a rotatable drum 12 includes clamp means 13. The clamp means includes a pair of levered elements 14 which each together define at their one end a pair of jaws 15. The jaws 15 are arranged to receive a hollow shaft 16 through which a vacuum can be drawn in the drum 12. Removed from the jaws 15, the lever elements 14 provide a common pivot point 17 with the end of an extension 18 remote to an arm 19 which is part of a moveable means 20 for moving the door 10 from a position closing the mouth 11 of the rotatable drum 12 to a position removed from the mouth 11.

Between the arm 19 and the extension 18, there is a mounting plate 21 on which a pair of pneumatic cylinders 22 are fixed. The ends of the cylinders 22 provide pistons 23 which are connected to free ends 24 of the lever elements 14. The opposite ends 25 of the cylinders 22 are connected with a pneumatic power source through hoses 26 which are connected to the T-piece 27. The hose 28 is connected to a pneumatic source through a solenoid valve 29 and a hose 30 as will be discussed in greater detail below.

The end 31 of arm 19 remote from the anchoring means 13 is secured to a tubular wall 32 forming a hinged anchorage means 33 for the door 10.

The tubular wall 32 is pivotally mounted about a central hinge pin 34 rotatable about an axis substantially rectilinear to the rotational axis 35 of the drum 12. The hinge pin 34 is held in position by means of two sets of four adjusting bolts 36 at the top and four adjusting bolts 36 at the bottom of the hinge pin 34. The bolts 36 are circumferentially spaced around the pin 34 at approximately ninety-degree intervals.

The bolts 36 are threaded in a circular support ring 37 and by adjusting nuts 38 the relative projection of bolts 36 into interior of wall 32 can be adjusted. The hinge pin 34 of the hinged anchorage means 33 can be moved transversely and axially relative to the rotational axis 35 of the drum 12. Thus, alignment of the door 10 relative to the mouth 11 of the drum 12 can be accurately effected and adjusted to account for manufacturing tolerances and wear during operation of the drum 12.

Wall 32 forms together with bushings 39, spacer plate 40, and thrust ring bearing 41 a composite housing for the hinged pivoted anchorage means 33. A bracket arm 42 is affixed by bolts 43 to a post 44 of the foundation means 45 for the door operating mechanism. This post 44 forms part of the foundation means 45 on which the rotatable drum 12 is mounted. Between the drum 12 and the foundation means 45 there are rollers and tracks on which the drum 12 can rotate.

Supported below the hinged anchorage assembly 33 there is provided a bracket 200 on which is mounted the solenoid valve 29 and a solenoid valve 46. Hose 47 is connnected through elbow member 48 to an open door port 49 of a door swing cylinder 50. Hose 51 is also connected with elbow 48 and is connected to a closed door port 52 of the door swing cylinder 50.

Bracket 42 provides an end wall 53 which is bored with an aperture to provide a shift 54 which is an extension to the end 55 of the door swing cylinder 50. The shaft 54 is mounted on lugs 56 affixed to the end 55. Nuts 57 to either side of the end wall 53 permit for the adjustment of the shaft 54 and hence the adjustment of the relative position of the door swing cylinder 50 in relation to the moveable arm 20. In this fashion, the effective degree of movement forward and rearward of the piston 58 is adjustable. Hereby the amount of movement or pressure of the door 10 on the mouth 11 of the drum 12 can be varied as required. The end of the piston 58 is provided with an eye 59 through which passes a bolt 60 to affix a pair of lugs 61 with the eye 59. The bolt 60 is affixed by means of a nut 62. The lugs 61 extend from the side wall 32 of the anchorage assembly 33 and as the piston 58 of the door swing cylinder 50 moves forwardly and rearwardly, the arm 19 is caused to move from the position wherein the door 10 is closed against the mouth 11 of the rotatable drum 12 of is removed from the mouth 11.

Around the perimeter 201 of the door 10, there are provided spaced lugs 202 which fit about the mouth 11 of the rotatable drum 12. These lugs 202 assist in aligning the door 10 with the mouth 11 such that if there has been undue wear or gross misalignment, interference will be encountered between the lugs 202 and the perimeter 201 of the outside of the wall 64 of the rotatable drum 12.

The hollow shaft 16 is affixed to the face 203 of the door 10 through a mounting plate 65 formed in the door face 203 substantially centrally about the rotational axis 35 of the rotatable drum 12. The end of the hollow shaft 16 for location on the mounting plate 65 provides a matching plate 66 which is suitably affixed by bolts 67 to the door face 203. The opposite end 68 of the hollow shaft 16 provides threads 69 for attachment of vacuum generating apparatus. Spaced inwardly of the threads 69, there is a collar 70 so that between another collar 300 on the stub shaft 16 and the collar 70 there is a defined space for accommodating the width of the jaws 15 between ends 204 and 205 of the lever elements 14 which effect anchorage with the door shaft 16. As illustrated in FIG. 3, it will seen that a small gap 71, measuring approximately one-quarter inch, exists between the end of collar 70 and the end portion 72 of the jaws 15. This gap 71 exists when the door 10 is closed about the mouth 11 and the arm 19 is extended in its furthest position as projected by the piston 58. In this position, the jaws 15 are in the position released or disengaged from the outside of the hollow shaft 16.

The operation of the door-operating mechanism together with the rotating drum is described with reference to the schematic of FIG. 4, which is the wiring diagram for operating the drum rotation, the vacuum pressure within the drum, and also the opening and closing of the door 10 through the moveable arm 19 and the operation of the clamp means 13.

At commencement of operation, the door 10 to the drum 12 is open and the drum 12 is loaded with products to be processed through the mouth 11 as required. The main operational timers of the circuit are now set, and here the overall timer 97 can be set to operate the rotational drum 12 for a period of, say, five hours. The auxiliary timer 99 regulates the amount of time that the drum 12 will rotate, and the auxiliary timer 100 the amount of time that the drum 12 will be stationary. These timers can be set, for instance, to one hour each.

Leads 73 and 74 are from a 120 volt AC power supply, and between lead 73 and the operational part of the circuitry there is a fuse 75. The main switch 76 between leads 73 and 74 can be set in the modes of manual (left position), off (central position), or automatic (right position). To start, the switch 76 is in the latter position, and power is applied on conductor 77 to the manual stop and start switches 78 and 79 wherein switch 79 is activated by pushing the closure button 79(a) to close terminals 80. Power is fed along line 81 through terminals 82 to the coil relay 83, which is then connected between leads 74 and 73. At this time, the contacts 84 are closed and simultaneously contacts 85 and 86 closed. Stop button 78(a) of switch 78 can be opened to break the contacts 207 and stop the operation of the circuit, should this be necessary.

With the main switch 76 closed on automatic, contact 208 is opened and contact 209 is closed. There is permitted a clamp release timer 232, and there is no energization of the clutch solenoid 92 in timer 232 because switch 90 is open. The clamp release solenoid 93 is also de-energized since there is no power across its terminals and hence the clamp elements 14 engage the shaft 16.

With power on line 81, there is also power on line 210 and with vacuum switch 88 closed, the vacuum solenoid valve 211 is energized through line 212. There is also power on line 213 which passes through the vacuum switch 95 which is closed when the vacuum is below 28 inches mercury. This, therefore, activates the vacuum pump motor starter 89 to commence generation of a vacuum.

Simultaneously, the closure of contact 209 of switch 76 puts power on line 214, which energizes the door swing solenoid valve 94 for the door swing cylinder 50. Energization of this valve causes the moveable arm 19 to start its arcuate movement to cause the door 10 to close on the mouth 11 of the container. The solenoid valve 94 in FIG. 4 is equivalent to the solenoid valve 46 in FIG. 2. The solenoid valve 93 of FIG. 4 is equivalent to the solenoid valve 29 of FIG. 2. Thus, the door 10 starts moving simultaneously with starting of the vacuum generating means as initiated by the vacuum pump motor starter 89.

Vacuum switch 90 is normally opened if the vacuum is less than 4 inches mercury. As soon as the vacuum exceeds this level, the switch closes and power is put on the clutch solenoid 215 of the timer 97. This also activates the motor 98 of timer 97 as contact 216 is closed. At this time also, contacts 217 and 218 move from the position shown in the drawing to contact, respectively, terminals 219 and 220.

This energizes the clamp release timer 232 and the switch 238 moves to contact terminal 221, thereby energizing the clamp release solenoid 93. The jaws 15 thereupon release from the shaft 16 and the door is held under vacuum on the mouth 11 of the drum 12. As such, the door 10 and drum 12 can rotate as an integral unit free from the jaws 15 of the clamp levers 14 of clamping means 13.

After timer 97 has run its time, contact 216 breaks and operation of motor 98 ends. Similarly, contacts 82 break and there is no power to the contact relay 83. At this time, contacts 84, 85, and 86 also open. Contact 218 remains in engagement with terminal 220 and thus there is power on line 81 and the right-hand side of the start button 79 of switch 78.

With contacts 82 open, the circuit of the vacuum pump motor starter 89 has no power and the vacuum generating pump stops. Similarly, there is no power on solenoid 211, and as this is de-energized a responsive valve permits air to enter the drum 12 through the hollow shaft 16.

When the vacuum pressure drops below 4 inches mercury, switch 90 opens and removes power from the timer solenoid 215 which opens contact 218 and 219 and thereby removes power from the door swing solenoid 94, which, being de-energized, moves to open the door 12. At this time, the jaw 15 moves to abutment with the collar 70 a distance of about 1/4 inch, as explained earlier. Also at this time, the timer 232 is activated and after a one-second time delay, power to the clamp release solenoid 93 is removed and the clamp moves to engage the outside of the shaft 16. As soon as the vacuum within the drum 12 drops to a level substantially equal to atmospheric pressure, the door swings open by the pressure of the door swing cylinder 50.

The various switches and contacts are all then in a position indicated in FIG. 4, which is the de-energized state of the schematic.

Switches 222 and 223, which operate together with the main switch 76, are safety switches operable with the manual mode of the processor as determined by switch 76 set to its left position. They act as isolating switches to prevent feedback currents when the circuitry is in automatic mode.

Lamps 224, 225, 256, 227, and 228 indicate the various states of operation of the processor, namely, forward running, stationary, reverse running, under vacuum, and in general processing mode. Switch 101 when set in the left-hand position permits the drum to rotate in reverse. In the right-hand position the drum 12 can rotate in the forward direction.

The vacuum switches 90 and 95 are connected through pressure-sensing terminals 229 and 230, respectively, to the vacuum pump and internal of drum 12 so as to be responsive to the various pressures within the drum.

The main switch 76 also operates contacts 104, which, in turn, activate speed control circuitry for the drum which is shown in block 105. The output 106 from the speed control circuitry activates a mechanical linkage of a hydraulic pump for rotating the drum 12. Power for circuitry 105 is obtained from a power supply 231 connected between leads 73 and 74 through the switch 104.

At commencement of operation of the door-activating mechanism, the jaws 15 are held fast with the hollow shaft 16 and the door is in an open position. After the drum 12 is loaded, the switch 76 is activated and the sequences described above follow. After the vacuum pressure within the drum 12, as generated through the vacuum pump, reaches the predetermined level of 4" Hg, the jaws 15 of the lever elements 14 are released from the shaft 16 by activation of the pistons 23 of the cylinders 22. The drum shaft 16 is now free to rotate as is the door 10 as a substantially integral unit together with the rotatable drum 12. In this fashion, the force, movement and vibration to the shaft 16 and hinge mechanism of the anchorage means 33 on the post 44 through arm 19 is minimized. Effective sealing of the drum through 11 and door 10 is maintained in this manner with the minimum of wear on the shaft 16 and hinge anchorage means 33. There is retained a residual pressure in the door swing cylinder 50 so that after release of the jaws 15 from the hollow shaft 16, the arm 19 swings slightly further inwardly towards the door face 203 under the residual pressure of the door swing cylinder 50. This creates the 1/4 inch gap between the end 72 of jaws 15 and collar 70.

In case of failure of the vacuum within the rotatable drum 12, the collar 70 insures that the jaws 15 are retained about the hollow shaft 16 so that although the shaft 16 is not restricted from rotating, the collar 70 and jaws 15 do restrict the door shaft 16 and door 10 from separating inadvertently from the arm 19.

As the rotatable drum wears during operation, any necessary adjustment to the position of the door 10 relative to the rotatable drum 12 can be effected by movement of the adjusting bolts 36 on the anchorage means 33 so that the door can be moved transversely or axially relative to the rotatable axis 35.

When the processing is complete, the vacuum is released and at about 4" Hg the door swing piston 50 causes the arm 19 to swing and the end 72 of jaws 15 to engage the collar 70. After a one-second time delay, the cylinders 22 are activated to cause the jaws 15 to clamp about the hollow shaft 16 and when the pressure within the rotatable drum is reduced to substantially atmospheric, the arm 19 under the action of the drum swing piston 50 draws the door 10 from the rotatable drum mouth 11.

Between the door 10 and the mouth 11 of the drum, there is provided a O-ring seal to insure that effective sealing of the closed drum can be achieved. The drum 12 provides on the inside 206 of wall 64 helical vanes or flights which permit processing of the drum contents, which can be food pieces such as meat chunks. The axis 35 of drum 12 is in this embodiment of the invention inclined to the horizontal axis so that drum rotation is effected at an incline. The end of drum 12 remote from the mouth 11 is a closed end.

Although, in the embodiment of the invention described, shaft 16 is hollow and is used for vacuum to be drawn in the drum 12, it is possible in other embodiments for the stub shaft 16 to be solid and for a suitable vacuum for the drum 12 to be provided at an appropriate central point on the axis at the closed end of the drum. In place of a stub shaft 16 for receiving the clamp means 13 an alternative receiving means on the door can be provided for engagement by the clamp means 13. Further, although a time-delay feature of one second has been described between the movement of the jaws 15 abutting the collar 70 and the time of engagement of the jaws 15 with the shaft 16, it will be appreciated that different time intervals can be set according to different predetermined operating characteristics.

The described embodiment has been made with reference to a rotatable drum; however, it is clear that the door-operating mechanism can have application to other containers which move in different fashions and which are adapted to be closed by a door which has, in the past, been mounted with a rigid connection such that forces are set up in the door mounting or the sealing is impaired between the container and door due to movement of the container relative to the door. This causes undesirable forces on the mounting means and impairment of the sealing means, and with this invention those disadvantages can be minimized.

The present embodiments of this invention are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims therefor are intended to be embraced therein.