US2785793A

US2785793A - Safety shut down for conveyor systems

Info

Publication number: US2785793A
Application number: US398534A
Authority: US
Inventors: Thomas F Murphy; Edward A Murphy
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-12-16
Filing date: 1953-12-16
Publication date: 1957-03-19
Anticipated expiration: 1974-03-19

Description

March 19, 1957 T. F. MURPHY HAL 2, 8 ,7

SAFETY SHUT DOWN FOR CONVEYOR SYSTEMS Filed Dec. 16 1953 2 Sheets-Sheet 1 LOCK ou-r LIMIT SWITCH SWITCH THOMAS P. MURPHY EDWARD A. MURPHY IN VEN TORS March 19, 1957 T. F. MURPHY EI'AL 2, 85,793

SAFETY snow DOWN FOR CONVEYOR SYSTEMS Filed Dec. 16 1953 2 Sheets-Sheet 2 THOMAS P. MURPHY EDWARD A. MURPHY IN V EN TORS (LIE United States Patent SAFETY SHUT DOWN FOR CONVEYOR SYSTEMS Thomas F. Murphy, Preakness, and Edward A. Murphy, Belleville, N. J.

Application December 16, 1953, Serial No. 398,534

Claims. (Cl. 198-232) This invention relates to conveyors or conveyor systeins and more particularly to a safety shut down mechanism which will shut down the feeding conveyors and other feeding means when the key conveyor in the system is stopped by breakage of parts, clogging or other conditions which will eifect stoppage of proper operation thereof. I

More specifically the present invention comprises a safety shut down mechanism for conveyor systems embodying a shear pin incorporated in the drive to the key conveyor in a system, which mechanism will upon breakage of the shear pin cut off the operating power to the key conveyor, and to the conveyors or mechanism feeding material to the key conveyor, thereby eliminating seri ous breakage of parts, excessive piling up of material being conveyed, etc., with elimination of the expense contingent with the correction of such undesirable conditions.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing a safety shut down for conveyor systems of a preferred form embodying the invention, and the feature forming the invention will be specifically pointed out in the claims.

In the drawings: 7

Figure 1 shows a diagrammatic view of a conveyor system of the type to which the present invention is employed.

Figure 2 is a diagrammatic view of the electrical circuit embodied in the conveyor system together with the safety shut down portion of the circuit.

Figure 3 is an end elevation of the safety shut down mechanism showing it applied to a fragment of a conveyor.

Figure 4 is a cross section of the line 4-4 of Figure 3 of the drawings showing the safety shut down mechanism in plan view.

In Figure 1 of the drawings a conveyor system is illustrated diagrammatically of the type which is employed in foundries for serving the dual purpose of separating the mold sand from castings and conveying the castings from the pouring floor to any desired point for transportation to locations for the chipping and machining of the castings. In this form of a conveyor system the sand and casting from the flasks are dumped first into a dump box shaker structure 1 wherein the sand and castings are initially separated and part of the sand is shaken loose from the castings. From the dump box shaker 1, the sand and the castings fall on the first of the feeder conveyors 2. The conveyor 2 delivers the sand and castings to a second feeder conveyor 3. From the second feeder conveyor 3 the sand and castings are delivered to the key conveyor 4 of the system where the sand falls off the lower end of the conveyor floor into a suitable receptacle or other conveying system and the castings with Such sand as still is clinging thereto are delivered 'ice V to' the final shaker 5 where the final separation of the sand and castings is provided and from which the castings are taken for withdrawal to any place for further work thereon such as cleaning, chipping or machining while the final sand is delivered from the shaker 5 to any suitable point which may be an additional conveyor system (not shown) carrying the sand back to a point for reuse.

In conveyor systems of this type in foundries, the metal castings and sand are dumped by laborers into the ini tial dump box shaker 1 as the castings cool in the flasks and oftentimes an excessive amount of castings are delivered which cause clogging of the conveyor system or overloading of the conveyor system with the result in breakage of parts etc. When any such undesirable conditions occur the castings and sand pile up on the con veyors resulting in further breakage, or spillage of the castings and sand off the sides of the conveyors as Well as other undesirable conditions which result in considerable expense for cleaning up and getting the conveyor system back in working conditions. The present invention embodies means for automatically shutting down the operation of the key conveyor and the feeding conveyors as well as the dump box shaker so as to prevent feeding of additional castings and sand to the key conveyor 4 in the event of stoppage of this conveyer for any purpose or reason whatsoever.

, In the conveyor system shown and in other companionable conveyor systems each of the different units such as a dump box shaker 1 the feeding conveyors 2 and 3 and the key conveyor 4 are each operated by independent electric motors indicated at 6. Referring to Figure 2, each motor has a starting circuit for individually energizing the motor circuit. The individual starting circuits for each motor are interlocked with one another such that those of

conveyors

4, 3 and 2 and shaker box 1 are 'circuit to the motor 6 of the key conveyor 4. The diagrammatic circuit shown in Figure 2 shows the individual motor controlling circuits with the circuit 11 for the dump shaker 1, the circuits 12 and 13 for the feeding conveyors 2 and 3 connected in the circuit in advance of the circuit 14 for the key conveyor 4 and the circuit 15 for the shaker 5 so that the lockout switch 10 will affect only the circuits 11, 12, 13 and 14 to cut off the flow of energizing electrical current to the motor 6 of the different units in advance of the key conveyor 4.

The lockout switch 10 is of any approved construction of electrical switch which may be purchased on the open market and it is operated by a relatively long arm 16 connected to the switch and extending laterally from one side of the switch. The switch arm 16 is of course of the usual pivoted type and is mounted -to swing laterally of the axis of a vertical plane extending through the switch 10 in other words referring particularly to Figure 4 of the drawings the arm 16 is mounted to move outwardly to open the switch 10 to cut off the flow of electrical energy through the circuit upstream of the lockout switch 10. The arm 16 has a disc 17 attached to its outer free end which is engaged by a pin 18 carried by the head 19. The head 19 is mounted on one end of an L-shaped arm 20. The arm 20 is slidably carried by suitable guide 21 which is in turn carried by or mounted on a driving element 22. The driving element 22 is keyed on the shaft 23 which is the driving shaft of the key conveyor 4 and it is connected to a driven element 24. The driven element 24 is connected to the driving chain 25 of the conveyor 4 and the driving and driven

elements

22 and 24 are connected by a shear pin 26 so that when the driving l men 22is driven bya-the motor 6 thru thesha'ft' 23$ theconnection of the shear pin'26 will cause the driven element24 to drive the chain 25 of the conveyor 4. new-- ever, inrthe event of clogging or stoppage of the conveyor 4 for any reason thechain 25 will of course stop, its move, ment, which will stop movement of the driven member 24. The' driving member 22 continuing'to be driven by 5 the motor 6 will exert a stress upon the shear pin 2d which a will break this pin, thereby breaking connection between driving element 22 and the driven element 24 and consecam surface '27 formed thereon on which a roller 28 .10 quently' cause. the element 22 to rotate independently of a the element 24; The driven element 24 has an inclined Carried bythe sli able arm 20 rests. So long. asfthe driven a the cam' surfaceffl'and'move the slidable armlfl. out; wardly co sing'the switch arm 16 to be moved. outwardly to break the electricalicircuit thruthelockout switch 1'0.v 7 and consequently cut ofi'the supply of operating electrical energy to the motors 6 of all'of theaunits in advance of the s key conveyor 4; '7 7 If it is so desired a protective housing 30 be mounted about

theelements

22 and 24 etc. to protectthem from fallingfisand, dust or the like.

Whilein the foregoing description, the safety shut down system of conveying is shown and described as particu 'larly'applicable' for use in casting conveying and cleaning systems in foundries, it is to be understood that the safety shut down above described and shown in the drawings may be employed in connection with any suitable type ofconveyor 'system*utilizing what might be in effect 3 key conveyor; and a series of one or more convcyors rfeediiig material to the-key conveyor so that upon stoppageof the-key conveyor all of the mechanism in advance or UP stream of -the' key conveyor would be stopped,

It'will be-nn'derstood' that the invention is not to be limited to the'specific construction or arrangement of Parts 7 shown, but that'thcy may be widely modified within the invention as defined by the claims.

What-is claimed is: 1. In a conveyor system having aplurality of conveyors,

driving means for each said conveyor, a control system for said driving means including therein a lcick-outswitchflnd at least one of the said conveyors operated by a dnivenv member connected thereto and further connected by a' shear pin to a driving member fixed to the shaft of *a driving means, and a lock-out switch actuating means comprising a cam surface on the said driven member and an axially slidable arm mounted on the said driving member and having one end adapted to engage the said cam surface and the other end adapted to open the said lock-out switch when the shear pin breaks.

2. The system of claim 1 wherein the axially slidable arm is L-shaped and said other end of the arm is disposed in alignment with the axis of said shaft.

3. The system of claim -1 wherein the-cut-out switch has a pivotedarm adapted to be movcdbysaid other end of the slidable arm;

4. The system of claim 1 whereinsaid cam surface ex tends on the driven member adjacent the shearing pin.

5. In a conveyor system having aplurality 'ofwconveyors, electricrmotors for driving said conveyors, circuits in series to energize each of the said electric motorsand-including therein a lock-out switch for deencrgizing said motors, said, switchhavinganarm pivoted at one end thereof, and at; least one of the said conveyors operatedby a dr'i-ven. member connected thereto and further connected by a shear pin to a driving member. fixed to theshaft of an electric motor, and a lock-out switch actuating means; comprising a cam surface on the said driven member, said cam surface extending transversely of said shaft and vdis-- posed on the driven member adjacent the shearpin, and an, axially slidable arm mounted on said driving member and, having one end adapted to engage said cam-surface and. the-other end of said arm being disposed in alignment with the axisof said shaft and adapted to move said pivoted switch arm when the shear pin breaks to open said switch and stop said conveyorsystem.

References Cited in thefile. of this-patent I UNITED STATES PATENTS Christensen -Sept.- 22,- 1953