US3216547A - Case stop - Google Patents

Description

Nov. 9, 1965 Filed Sept. 20, 1965 M. J. DE GOOD ETAL CASE STOP 4 Sheets-Sheet l @WIM Nov. 9, 1965 M. J. DE GOOD ETAL 3,216,547

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United States Patent O 3,216,547 CASE STOP Maynard J. De Good and Ciyde L. Bowman, Grand Rapids, Mich., assignors to The Rapids-Standard Company, Inc., Grand Rapids, Mich., a corporation of Michigan Filed Sept. 20, 1963, Ser. No. 310,393 9 Claims. (Cl. 193-32) This application is a continuation-in-part of our copending application, Serial No. 98,143, filed March 24, 1961 entitled Case Stop for a Conveyor, now United States Patent No. 3,116,818.

This invention relates to motorized case stops of the type used to interrupt the ow of articles moving along a conveyor. It is particularly concerned with a case stop powered by a constantly operating prime mover. The portion of the assembly which makes actual article engagement is connected lto the prime mover by a lost motion or overriding connection, permitting the prime mover, when desired, to operate without moving the case stop irrespective of whether the stop is extended or retracted.

Case stops of this type must lbe capable of positively arresting the movement of the articles. In so doing, they must be rugged enough to withstand the pressure of the accumulated articles they are holding back and to withstand the impact of the articles when their forward motion is arrested. At the same time, these case stops must effect both positive release and positive arrest of the articles.

One of the major disadvantages of the present type of case stops is that they do not effect positive arrest of the articles. This is true even though the conveyor is equipped with singulation devices (automatic article spacing) as shown in U.S. Patent No. 3,062,359. Even with singulation, it has been found necessary to provide positive stop erection.

This invention is an improvement on the structure shown in application Serial No. 98,143. In the present invention, the stop is positively erected by the motor. Retraction is initiated by the motor and completed by the weight of the stop itself. It is also an improvement because it is simpler and, therefore, less costly and less bulky. Further, in this invention, the prime mover is permitted to operate continuously. This greatly increases the life of the prime mover and eliminates the circuitry necessary to interrupt its power source. Further, this structure eliminates the problem of motor overrun which is characteristic of any structure depending upon the stopping and starting of a prime mover.

It is, therefore, an object of this invention to provide a case stop which will positively erect the stop and hold it in erected position without interruption of the operation ofthe prime mover.

A further object of this invention is a case stop in which the impact of arresting the articles and the subsequent pressure exerted by arrested articles is not transmitted to the prime mover or the control mechaism.

These and other objects and advantages of this invention will become more apparent upon reading the specification in conjunction with the accompanying drawings.

In the drawings:

FIG. 1 is a fragmentary plan view of a gravity conveyor equipped with a case stop constructed in accordance with the teachings of this invention;

FIG. 2 is a schematic, fragmentary side elevation view showing the case stop in erected position;

FIG. 3 is a view similar to FIG. 2 showing the case stop in retracted position;

FIG. 4 is a plan view of the case stop;

FIGS. 5 and 6 are sectional elevation views taken along the plane V--V showing in progressive order the mecha- Nice nism as in passes through a normal operating cycle when prolonged interruption of article ow is not desired;

FIGS. 7 and 8 are sectional elevation views taken along the same plane as FIGS. 5 and 6 showing in progressive order the mechanism as it passes through an operating cycle when prolonged interruption of article flow is desired;

FIG. 9 is a sectional elevation view taken along the plane IX-IX of FIG. 4 (omitting the prime mover) showing the mechanism in erected position;

FIG. 10 is a view similar to FIG. 9 showing' the mechanism in retracted position;

FIG. l1 is a sectional elevation view (omitting the prime mover) taken along the plane XI-XI of FIG. 4;

FIG. 12 is a sectional elevation view (omitting the prime mover) taken along the plane XII-XII of FIG. 4;

FIG.-l3 is a fragmentary plan view of this invention applied to a conveyor having a power driven propelling member; and

FIG. 14 is a plan view similar to FIG. 4 but showing the mechanism adapted for the type of conveyor illustrated in FIG. 13.

In executing the purposes of this invention, a conveyor stop is provided having a power source which drives a lost motion or override connection. When the lost motion connection is positioned in one attitude, the prime mover causes the case stop to become erected. Thereafter, the prime mover continues to operate without shifting the stop. When the lost motion connection is shifted to a second attitude, the stop is shifted to retracted position and thereafter, the prime mover continues to operate while the case stop remains retracted. The mechanism includes an over-center toggle which supports and locks the stop in erected position. On retraction, the motor unlocks the toggle and thereafter, the weight of the stop completes the retraction movement.

Referring specifically to the drawings, the numeral 10 indicates a conveyor of conventional design having a pair of spaced side rails 11 and a plurality of transverse axles 12 connecting the side rails 11. Each of the axles 12 mounts a plurality of conveyor wheels. These collectively form a conveying surface and support the articles being moved along the conveyor. Extending between the rails are a pair of cross braces 14 from which depends the case stop assembly 15.

The case stop 15 has a frame 16 (FIGS. 4, l1 and l2). Seated in the frame is a link member or beam 20. One end of the beam 20 is pivoted at 21 to the frame 16. The other end of the beam 20 has a pair of upstanding fingers 22 which, when erected, project up through the conveying surface and intercept the articles moving along the conveyor (FIG. 2). It will be recognized for the purposes of this invention that many different types of structures may be substituted for the fingers 22. For instance, a plate may be substituted for theA fingers. The sides of the fingers may be equipped with conveyor wheels to reduce the friction incident to contact with the articles as they shift between erected and retracted positions. These minor modifications are conventional in the manufacture of case stops and, therefore, are not considered to be a part of this invention and further description of them is not considered warranted.

R-otatably mounted to the frame is a shaft 23 having a toggle assembly 24 secured to it (FIGS. 4 and 9). The lower link 25 of the toggle is secured to the shaft 23 and rocks with it. The upper link 26 of the toggle is secured to a stud 27 which in turn is attached to the beam 20. The upper end of the lower link 2S is connected to the beam by a tension spring 28. This spring biases the toggle assembly 24 not only into erected" position, but over-center to effect a lock supporting the beam 20 in erectedv position.

Also secured to the shaft 23 is a lever 30 (FIG. 5 The free end of the lever is equipped with a pin 31. This pin cooperates with an opening 33 in the bar 32. The opening 33 consists of an upper slot 34 and a lower slot 35. These slots communicate through a channel 36 where they overlap (FIG. 6). The pin 31 seats in this opening and may shift from one slot to another by traversing the channel 36. This is the linkage. The bar 32 is normally in its lowered position as illustrated in FIGS. and 6. It is biased into this position by its own weight.

The other end of the bar is pivotally connected at 37a to an eccentric 37 which in turn is secured to the shaft 38. The shaft 38 is driven by a prime mover 39 (FIG. 4) through a speed reducer so that the effective speed of rotation ofthe shaft 38 is substantially less than that of the motor. The speed reducer is not separately illus trated since it may be incorporated within the housing of the prime mover itself.

Also mounted to the frame 16 is a rock shaft 40 (FIGS. 4 and 5). Secured to the rock shaft is an arm 41 on the free end of which is a camming rol-ler 42. Also secured to the rock shaft 40 is a strap 43 (FIGS. 4 and 11). A spring 45 connects the strap 43 to an actuator 44. The actuator 44 may be any suitable piece of equipment such, for example, as a solenoid. A portion of the lower end ,of the bar 32 is notched at 46 to providel clearance for the rock shaft 40 (FIG. 5).

The beam 20 is partially biased into erected position by a spring 50 (FIGS. 4 and 12). One endl of the spring is secured to the angle 51 which in turn is secured to the frame 16 of the case stop 15. The other end of the spring 50 is attached to a depending foot piece 52 which itself is rigidly secured to the beam 20. The strength of the spring 50 is such that it relieves the prime mover 39 of most of the weight of the beam 20. However, the spring alone cannot support the beam and thus when the prime mover unlocks the toggle, the weight of the beam will shift the beam to retracted position.

Operation Considering the beam 20 to be in its down or retracted position as illustrated in FIG. 5, when the prime mover 39 is energized, the rotation of the shaft 38 will cause the eccentric 37 to reciprocate the bar 32. As the bar 32 is shifted to the left from the position illustrated in FIG. 5, the bar 32 will merely slide past the pin 31 and no motion will be transmitted to the pin (FIG. 6).

In this attitude, the stop will remain retracted. When the stop remains retracted, the cam 42 remains down or inactive. Upon activation of the actuator 44, the cam 42 will be rocked upwardly lifting the bar 32. Should the bar 32 be in a position where the pin 31 prevents upward movement of the bar 32 when the cam is rocked, the spring 45 (FIG. 11) will permit the actuator 44 to complete its action even through the cam 42 cannot follow. However, as soon as the pin aligns with the channel between the slots 34 and 35, the bar 32 will shift and the pin will then be seated in the lower slot 35. This will occur when the bar reaches the end of its stroke to the right as illustrated in FIG. 7.

As the bar 32 shifts to the left as illustrated in FIG. 8, the right hand end wall of the lower slot 35 Will push the pin 31 to the left, erecting the toggle (FIG. 9). Thus, the beam 20 is forcibly erected. As the toggle 24 nears erection, the spring 28 will shift it over-center, locking the beam 20 in erected position. Thereafter, the bar 32 may shift to the left without transmitting motion to the pin 31 because of the lost motion connection provided by the slot 35.

Because the toggle 24 is in over-center or locked position as shown in FIG. 9, the beam 20 will remain erected even through it is unsupported by the prime mover 39. The bias of the spring 28 assures the over-center position for the toggle.

The beam will remain in erected position until the cam 42 is rocked down. When this happens, the bar 32 will drop shifting the pin 31 to the upper slot 34. The next shift of the bar 32 to the right will cause the left hand end wall of the slot 34 to engage the pin, pulling the toggle into folded position. Once the toggle passes center, the weight of the beam 20 will cause it to drag. However, should the articles on the conveyor exert such pressure on the lingers 22 as to prevent this, the positive engagement between the pin and b-ar will assure forcible retraction by the prime mover. If it is desired to hold the beam 20 in erected position for an extended period, this is accomplished by energizing the actuator 44. If the beam 20 is to remain retracted, the actuator 44 is de-energized or released.

Control of the actuator 44 may be effected by any suitable means. In FIG. ll, the actuator is shown connected to a power source through a pair of conductors 48 one of which is equipped with a switch 49. This switch may be manually operated or alternately it may be responsive to automatic devices. For example, it may be operated by a sensing mechanism responsive to certain flow con@ ditions along the conveyor or to the availability of conveying space on a conveyor line from which articles are received by the conveyor equipped with the case stop. It may be responsive totiming devices which limit the movement of articles to certain predetermined intervals.

For purposes of illustration, the actuator is assumed to be a solenoid which when energized retracts the plunger 46. This motion, through the spring 45, rocks the strap 43 to the right, as the structure is illustrated in FIG. ll. This erects the arm 41 bringing the camming wheel 42 into -contact with the bottom of the bar 32. The upward movement of the wheel 42 raises the free end of the bar 32, automatically shifting the pin 31 from the upper slot 34 to the lower slot 35, as shown in FIGS. 7 and 8. This wheel thus shifts the connection from one position or ata titude to another. Should the camming wheel 42 be raised while the bar is in a position where the pin cannot shift from one slot to the other, the overriding connection between the solenoid 44 and the strap 46 will permit the plunger of the solenoid to complete its travel even though the arm 41 cannot complete its movement. The spring 45 will apply sufficient bias to effect upward movement of the bar 32 when a point in the cycle is reached which permits the pin to shift slots. On retraction, it will be recognized that the camming Wheel merely drops away and the bar wil-l drop by gravity when the pin reaches the channel connecting the slots 34 and 35.

When the beam 20 is in its extended or erected position, the line pressure, of the articles piled up against 1t will not be exerted on the prime mover or on lthe pin. This will be absorbed by the shaft or pivot 21 and thus transmitted directly to the frame 16. This eliminates all danger of the prime mover being overloaded by reason of line pressure. Further, it is impossible for the articles to forcibly retract the erected stop, because the toggle 24 having been shifted to or slightly over-center, as illustrated in FIG. 9, cannot be caused to shift into a folded position, irrespective of the downward pressure applied through the fingers 22.

FIGS. 13 and 14 illustrate this linvention applied to a conveyor having a power driven propelling member. The conveyor 60 is quite similar to the conveyor illustrated in FIG. 1. The conveyor 60 has a pair of side frame members 61 joined by axle 62 equipped with conveyor wheels 63. vTraveling through the center of the conveyor is a powered propelling member or belt 64, the direction of movement of which is indicated by the arrow in FIG. 13. The case stop 15a is suspended beneath Vthe conveyor by suitable cross lbraces 65. In this construction, the up standing article engaging ngers 22 straddle the propel ling member, one on each side.

The case stop 15a is identical to the case stop I5 except that by reason of the presence of the powereell propelling member 64 the power to `drive the case stole Qau lle.. Clt?- '5 rived from the propelling member. This eliminates the necessity for the prime mover. This is done by providing a wheel 66 which engages the return run 64a of the propelling member 64. The wheel 66 is continuously rotated by the propelling member and its motion is transmitted to the supporting shaft 67. The eccentric 37 is driven by the shaft 68. The motion of the shaft 67 is transmitted to the shaft 68 through a Speed reducer 69 to reduce the cycling time of the case stop.

The remainder of the structure of the case stop is identical to the case stop except that some of the operating equipment is shifted slightly to one side to provide adequate space for passage of the return run 64a of the propelling member through the frame ofthe case stop. Except that the power for driving the case stop is desired from the propelling member, the operation of the case stop 15a is identical to the operation of the case stop 15. The use of this type of a drive mechanism to drive power from a propelling member is the subject of co-pending patent application, Serial No. 203,860, iiled I une 20, 1962, now Patent No. 3,136,406 entitled Improvement in Operational Controls, which application has a common assignee with this invention.

To reduce line pressure when Ithis case stop is used on a powered conveyor such as is suggested in FIGS. 13 and 14, a pressure release accumulator type conveyor may be employed. Reference is madeto United States Patent 3,062,- 359 as illustrating such a conveyor.

It will .be seen that this invention provides a simple case stop having a minimum number of operating parts. At the same time, it provides a positive stop for the articles. Its structure is such that the power source, whether it be a prime mover or the return run of the propelling member, is relieved of providing the energy necessary to resist the line pressure of the articles that are bearing against the stop. The invention provides both a positive erection and a positive 'retraction mechanism for the stop fingers. It also permits the prime mover to operate continuously both when the lingers are erected and when they are retracted.

While there has been shown a preferred embodiment of this invention ytogether with a -modiiication thereof, it will be understood that other modifications may be constructed incorporating the principles of this invention. Such of these modifications as incorporate the principles of this invention are to be considered as included in the hereinafter appended claims unless these claims by their language expressly state otherwise.

We claim:

1. An article stop for a conveyor, said article stop having power driven means and a frame mounting the same; an article interception means movable between an erected position and a retracted position; said article interception means being biased into retracted position; a member constantly reciprocated by said power driven means; a shiftable connection between said member and said article interception means, said connection when shifted to one position transmitting said reciprocating motion to said article interception means and moving said -article interception means to erected position; said connection when so shifted and said article interception means is in erected position Ibeing a lost motion connection permitting said member to reciprocate without transmission of motion to said article interception means; said connection when shifted Ito said other position shifting said article interception means from erected to retracted positions; said connection when shifted into said other position and said article interception means is retracted being a lost motion connection permitting said member to reciprocate without transmission of motion to said article interception means; a movable camming element for holding said connection in said one position; a locking element for positively holding said article interception means in erected position.

2. An article stop for a conveyor, said article stop having a frame mounting a prime mover; a bar secured at one of its ends to and reciprocated by said prime mover; a member pivotally mounted at one of its ends to said frame, `the other of its ends movable between erected and retracted positions; said other of said members ends having article interception means; a toggle supporting said other end of said member, said toggle when open holding said article interception means in larticle engaging position and when folded retractng said article interception means to inactive position; biasing means urging said toggle into over-center locking position when open; a toggle operating linkage engaging said bar; means for Vshifting said bar with respect to said linkage between a first position and a second position; when said bar is in said first position said bar in one direction of movement engaging said linkage and shifting said toggle to open position and on opposite movement of said 'ba-rpermitting said bar to move relative to said linkage and without transmission of motion to said linkage; said bar when shifted to said second position connecting said linkage to :said bar and folding said toggle upon movement Iof said bar in 'a direction opposite to that which opened said toggle; said bar when .so shifted and said toggle folded being disconnected from said toggle t-o the extent said bar may reciprocate without transmission of motion to said toggle.

3. An article stop for a conveyor, said article stop having a frame mounting a prime mover; a bar secured at one of its ends to and reciprocated by said prime mover; a member pivotally mounted at one of its ends to said frame, the other of its ends movable between erected and retracted positions; said other of said members ends having article interception means; a 'toggle supporting said other end of said member, said toggle when open holding said article interception means in article engaging position and when folded retracting said article interception means to inactive position; a toggle operating linkage engaging said bar; means for shifting the relationship between said bar and said linkage between a first position and a second position; when said bar and linkage are in said iirst position relative to each other, said bar in one direction of movement engaging said linkage and shifting said toggle to open position and on opposite movement of said bar permitting said bar to return to its original position while said toggle remains open; when the relationship between said bar and said linkage is shifted to said second position said bar engaging said linkage and shifting said toggle to folded position as said bar moves in a direction opposite to said one direction; on opposite movement of said bar and said bar moving relative to said linkage without transmission of motion to said linkage.

4. An article stop for a conveyor as described in claim 3 wherein there is provided resilient means urging said toggle into and over-center locking position when open.

S. An article stop for a conveyor as described in claim 2 wherein said bar has a pair of openings communicating with each other and said operating linkage has a pin seated in one of said openings when said bar is in said iirst position; said shifting of said bar relocating said pin in the other of said openings.

6. An article stop for a conveyor, said article stop having a frame mounting a power driven means; a bar secured at one of its ends to and reciprocated by said power driven means; a link member pivotally mounted at one of its ends to said frame; the other of its ends having article interception means; a toggle supporting said other end of said link member, said toggle when open holding said article interception means in article engaging position and when folded retracting said article interception means to inactive position; a toggle operating pin; an opening adjacent thc other of the ends of said bar, said opening being characterized by a pair of laterally offset slots overlapping for a portion of their lengths to form a channel between said slots; said pin being received in said opening and normally seated in one of said slots; means for shifting the position of said bar with respect to said pin whereby said pin is made to seat in the other of said slots; when said pin is in said one slot said bar in one direction of movement engaging said pin and shifting said toggle to folded position and on opposite movement of said bar said bar sliding past said pin without transmitting any motion to said toggle; when said pin is seated in said other slot said bar on movement in said opposite direction engaging said pin and shifting said toggle to open position, said bar on movement in said one direction sliding past said pin without transmission of motion to said toggle; said link member Abeing biased in retracted position.

7. An article stop for a conveyor, said article stop having a frame mounting a power driven means; a bar se- 4curedrat one of its ends to and reciprocated by said power driven means; a member pivotally mounted at one of its ends to said frame, the other of its ends being movable between erected and retracted positions; said other of said members ends having article interception means; a toggle supporting said other end of said member, said toggle when open holding said article interception means in article engaging position and when folded retracting said article interception means to inactive position; a toggle operating linkage having a pin; an opening adjacent the other of the ends of said bar, said opening being characterized by a pair of laterally oiset slots overlapping for a portion of their lengths to form a channel between said slots; said pin being received in said opening and normally seated in one of said slots; means for shifting the position of said bar with respect to said pin whereby said pin is made to seat in the other of said slots;

' when said pin is in said one slot said bar in one direction of movement engaging said pin and shifting said toggle to folded position. and on opposite movement of said bar, said bar sliding past said pin without transmission of motion to said toggle; when said pin is seated in said other slot said bar on movement in said opposite direction engaging said pin and shifting said toggle to open position; said bar on movement in said one direction sliding past said pin without transmission of motion to said toggle; said member being biased into retracted position.

8. An article stop for a conveyor as described in claim 7 wherein said toggle operating linkage has .a shaft rockably mounted on said frame; an arm and one end of said toggle secured to said shaft for simultaneous movement;

said pin being mounted on said arm; the other end of said toggle being secured to said member.

9. An article stop for a conveyor as described in claim 8 wherein said means for shifting said bar has a rock shaft rotatably mounted to said frame; a lever on one end of said rock shaft, said lever engaging said bar and upon rocking movement of said rock shaft shifting said bar with respect to said pin; means for rocking said rock shaft.

References Cited by the Examiner UNITED STATES PATENTS 2,769,520 11/56 Davidson et al. 198-26 3,062,359 11/56 McGow et al. 198-160 3,116,818 1/64 De Good et al 198-32 3,156,345 11/64 De Good 198-127 3,164,246 1/65 De Good 198--100 HUGO O. SCHULZ, Primary Examiner.

SAMUEL F. COLE, Examiner.

Claims (1)

1. AN ARTICLE STOP FOR A CONVEYOR, SAID ARTICLE STOP HAVING POWER DRIVEN MEANS AND A FRAME MOUNTING THE SAME; AN ARTICLE INTERCEPTION MEANS MOVABLE BETWEEN AN ERECTED POSITION AND A RETRACTED POSITION; SAID ARTICLE INTERCEPTION MEANS BEING BIASED INTO RETRACTED POSITION; A MEMBER CONSTANTLY RECIPROCATED BY SAID POWER DRIVEN MEANS; A SHIFTABLE CONNECTION BETWEEN SAID MEMBER AND SAID ARTICLE INTERCEPTION MEANS, SAID CONNECTION WHEN SHIFTED TO ONE POSITION TRANSMITTING SAID RECIPROCATING MOTION TO SAID ARTICLE INTERCEPTION MEANS AND MOVING SAID ARTICLE INTERCEPTION MEANS TO ERECTED POSITION; SAID CONNECTION WHEN SO SHIFTED AND SAID ARTICLE INTERCEPTION MEANS IS IN ERECTED POSITION BEING A LOST MOTION CONNECTION PERMITTING SAID MEMBER TO RECIPROCATE WITHOUT TRANSMISSION OF MOTION TO SAID ARTICLE INTERCEPTION MEANS; SAID CONNECTION WHEN SHIFTED TO SAID OTHER POSITION SHIFTING SAID ARTICLE INTERCEPTION MEANS FROM ERECTED TO RETRACTED POSITIONS; SAID CONNECTION WHEN SHIFTED INTO SAID OTHER POSITION AND SAID ARTICLE INTERCEPTION MEANS IS RETRACTED BEING A LOST MOTION CONNECTION PERMITTING SAID MEMBER TO RECIPROCATE WITHOUT TRANSMISSION OF MOTION TO SAID ARTICLE INTERCEPTION MEANS; A MOVABLE CAMMING ELEMENT FOR HOLDING SAID CONNECTION ING SAID ONE POSITION; A LOCKING ELEMENT FOR POSITIVELY HOLDING SAID ARTICLE INTERCEPTION MEANS IN ERECTED POSITION.

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