Safety control system for power operated equipment

• US 5,272,946 A
• Filed: 03/20/1992
• Issued: 12/28/1993
• Est. Priority Date: 03/20/1992
• Status: Expired due to Fees

• Current Assignee: Bettcher Industries Incorporated
• Original Assignee: Food Industry Equipment International, Inc.
• Inventors: Masters, David A., McCullough, Timothy J.
• Primary Examiner(s): JONES, EUGENIA A
• Application Number:
  US07/855,768
• Time in Patent Office: 648 Days
• Field of Search: 83/DIG. 1, 83/58, 83/478, 83/788, 83/814, 83/816, 83/818, 83/819, 192/129 A, 192/130, 192/131 R, 192/93 C, 192/71, 452/125, 452/127
• US Class Current: 83/58
• CPC Class Codes: B27B 13/14 Braking devices specially designed for band sawing machines, e.g. acting after damage of the band saw blade
• CPC Class Codes: F16P 3/12 with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine F16P3/08 takes precedence
• CPC Class Codes: Y10S 83/01 Safety devices
• CPC Class Codes: Y10T 83/081 With randomly actuated stopping means
• CPC Class Codes: Y10T 83/707 By endless band or chain knife
• CPC Class Codes: Y10T 83/7258 By fluid means

Abstract

A safety control system for power operated equipment which ensures operator safety by immediately disconnecting the power drive from a power driven rotating member, such as a toothed feed shaft of a meat skinning machine or a moving blade of a band saw, and then positively stops and then reverses the direction of movement of the rotating member, upon a metal conductive glove worn by the operator, contacting the blade or toothed shaft. The operator'"'"'s glove is electrically connected to a safety mechanism and upon the glove completing a circuit upon contact with the rotating member or equipment immediately disconnects the power drive from the rotating member by actuating a clutch or tensioning cylinder. A trigger mechanism then is actuated and permits a positive stopping element to engage and stop the moving element. A power actuated plunger then is actuated and moves the stopping element in an opposite direction to reverse the direction of the rotating member in an incremental step to further reduce the possibility of injury to the operator. A moisture impervious dielectric plastic glove preferably is worn by the operator to prevent the moisture in the meat from conducting current between the metal glove and machine until the plastic glove is cut and contact made with the metal glove. A switch requires manual actuation to connect the power drive to the rotatable member. The metal gloves are connected to the safety switch by electrodes secured to the metal gloves.

Claims

1. A safety control system for power operated equipment of the type having a moving metal component including:

a) motor means operatively connected to the metal component for moving said component in a forward direction;

b) electrical conductive gloves adapted to be worn by an operator of the power operated equipment;

c) first means for operatively connecting and disconnecting the motor means to and from the moving metal component;

d) second means independent of the motor means for positively stopping the movement of the metal component in the forward direction upon the first means disconnecting the motor means from the moving metal component;

e) third means independent of the motor means for reversing the direction of movement of the metal component; and

f) electric circuit means operatively connected to the conductive gloves for controlling the operation of the first, second and third means for preventing injury to the operator if at least one of the operator'"'"'s conductive gloves or portion of the operator'"'"'s body contacts the moving metal component.

2. The safety control system defined in claim 1 in which the metal component includes a shaft and a drive sprocket for operatively connecting said shaft to the motor means;

and in which the first means includes a clutch for drivingly connecting said shaft to the drive sprocket.

3. The safety control system defined in claim 2 in which the clutch includes a hub attached to the shaft, a plurality of balls, and a movable camming member operatively engaged with the hub and with the balls for moving the balls into driving engagement with the drive sprocket upon contact of one of the operator'"'"'s gloves with the moving component.

4. The safety control system defined in claim 3 in which a clutch actuation piston is operatively engageable with the movable camming member;

and in which said piston moves said camming member into engagement to actuate the clutch.

5. The safety control system defined in claim 2 in which the second means includes a pawl wheel securely mounted on the shaft, a movably mounted pawl located adjacent the pawl wheel, and a trigger assembly operatively engageable with the pawl for permitting said pawl to move into stopping engagement with the pawl wheel.

6. The safety control system defined in claim 5 in which the trigger assembly includes a trigger and a solenoid engageable with the trigger for engaging and disengaging the trigger and the pawl.

7. The safety control system defined in claim 5 further including a trigger assembly mounting plate, said plate being pivotally mounted on the shaft.

8. The safety control system defined in claim 7 in which the trigger assembly mounting plate is formed with an arcuate slot;

in which a fixed cam bolt extends through said slot; and

in which the pawl has a cam plate adapted to engage the fixed cam bolt upon pivotal movement of the trigger assembly mounting plate to disengage the pawl from the pawl wheel.

9. The safety control system defined in claim 7 in which the third means includes a pressure actuated piston mounted on the trigger assembly mounting plate;

and in which said piston pivotally moves the plate and pawl to reverse the movement of the shaft through engagement of the pawl with the pawl wheel.

10. The safety control system defined in claim 7 in which switch means is mounted on the trigger assembly mounting plate and is actuated by the pawl upon disengagement of the pawl from the pawl wheel.

11. The safety control system defined in claim 5 including spring means for biasing the pawl toward stopping engagement with the pawl wheel.

12. The safety control system defined in claim 1 in which the moving component is a blade of a band saw;

in which the blade extends about a pair of spaced pulleys;

in which one of the pulleys is power driven and is rotatably mounted on a swinging arm; and

in which the first means includes a piston connected to said swinging arm for moving said power driven pulley into and out of driving engagement with the blade of the band saw.

13. The safety control system defined in claim 1 in which the moving component is a blade of a saw;

in which the second means includes a movable wedge block formed with a cutout;

in which a wedge is independently movable within the cutout and forms a slot with a portion of said wedge block through which the blade moves; and

in which a lever is engageable with the wedge for moving said wedge toward the slot to pinch the blade against said wedge block portion to stop movement of the blade.

14. The safety control system defined in claim 1 in which the electric circuit means includes a diagnostic logic circuit.

15. A control system for power operated equipment of the type having a moving metal component including:

a) power means operatively connected to the metal component for moving said component in a forward direction;

b) electrical conductive gloves adapted to be worn by an operator of the power operated equipment;

c) first means for operatively connecting and disconnecting the power means to and from the moving metal component;

d) second means independent of the power means for positively stopping the movement of the component in the forward direction upon the first means disconnecting the power means from the moving metal component, and for sequentially reversing the direction of movement of the metal component; and

e) electric circuit means operatively connected to the conductive gloves for controlling the operation of the first and second means for preventing injury to the operator if at least one of the operator'"'"'s conductive gloves or portion of the operator'"'"'s body contacts the moving metal component.

16. The control system defined in claim 15 in which the second means includes a stopping member operatively engageable with the moving component for stopping said component, and a trigger assembly engageable with the stopping member for controlling movement of the stopping member into positive stopping engagement with the moving component.

17. The control system defined in claim 16 in which the trigger assembly includes a lever having a first end releasably engageable with the stopping member and a second end actuated by a solenoid for effecting engagement of said first end with the stopping member.

18. A safety control system for power operated equipment of the type having a moving band saw blade including:

a) a pair of spaced pulleys about which the saw blade extends, one of said pulleys being power driven and rotatably mounted on a swinging arm;

b) motor means operatively connected to the power driven pulley for moving the saw blade in a forward direction;

c) electrical conductive gloves adapted to be worn by an operator of the power operated equipment;

d) first means for operatively connecting and disconnecting the motor means to and from the power driven pulley including a piston connected to the swinging arm for moving said power driven pulley into and out of driving engagement with the saw blade;

e) second means for positively stopping the movement of the saw blade in the forward direction;

f) third means for reversing the direction of movement of the saw blade; and

g) electric circuit means operatively connected to the conductive gloves for controlling the operation of the first, second and third means for preventing injury to the operator if at least one of the operator'"'"'s conductive gloves or portion of the operator'"'"'s body contacts the moving saw blade.

19. A safety control system for power operated equipment having a moving metal saw blade including:

a) motor means operatively connected to the saw blade for moving said saw blade in a forward direction;

b) electrical conductive gloves adapted to be worn by an operator of the power operated equipment;

c) first means for operatively connecting and disconnecting the motor means to and from the moving saw blade;

d) second means for positively stopping the movement of the saw blade in the forward direction, said second means includes a movable wedge block formed with a cutout, and a wedge independently movable within the cutout and forming a slot with a portion of said wedge block through which the blade moves; and

a lever engageable with the wedge for moving said wedge toward the slot to pinch the blade against said wedge block to stop movement of the blade;

e) third means for reversing the direction of movement of the saw blade; and

f) electric circuit means operatively connected to the conductive gloves for controlling the operation of the first, second and third means for preventing injury to the operator if at least one of the operator'"'"'s conductive gloves or portion of the operator'"'"'s body contacts the moving saw blade.

20. The safety control system defined in claim 19 in which plunger actuated trigger means is engageable with the lever for controlling movement of said lever and of the wedge.

21. The safety control system defined in claim 20 in which the wedge is spring biased toward pinching engagement with the saw blade;

and in which the third means include a pressure actuated piston which is engageable with the wedge block for moving said wedge block, pinched blade and wedge in a reverse direction.

22. The safety control system defined in claim 21 in which the electric circuit means includes a sensor mounted on the wedge block;

and in which said sensor is actuated by the movement of the wedge.