US3866537A

US3866537A - Transfer mechanism

Info

Publication number: US3866537A
Application number: US442235A
Authority: US
Inventors: Joachim P C Minkwitz
Original assignee: ROCKFORD AUTOMATION Inc
Current assignee: ROCKFORD AUTOMATION Inc
Priority date: 1974-02-13
Filing date: 1974-02-13
Publication date: 1975-02-18
Anticipated expiration: 1992-02-18

Abstract

The mechanism is incorporated in a conveyor system of the type which propels vehicles, or pallets, by frictional contact between a rotating drive shaft and a drive wheel carried by the vehicle. The disclosed conveyor system includes two such rotating drive shafts and associated parallel tracks. The mechanism transfers the vehicles from one set of parallel tracks to the other via concentric tracks. An upright drive shaft drives a radiallyextending pivoted arm on which is mounted an elongaged, arcuate member. The member has a downwardly inclined ramp at its front to ride over any preceding vehicle, and a depending dog at its rear to engage the vehicle and advance it. A ramp raises the arm at the outlet of the concentric tracks to disengage the vehicle, and lowers the arm to operative position at the inlet thereof.

Description

Unite States Patent [1 1 Minkwitz Feb. 18, 1975 TRANSFER MECHANISM [75} Inventor: Joachim P. C. Minkwitz, Leaf River,

[73] Assignee: Rockford Automation, Inc.,

Rockford, Ill.

[22] Filed: Feb. 13, 1974 211 Appl. No.: 442,235

FOREIGN PATENTS OR APPLICATIONS 323,535 8/1920 Germany 104/163 Primary ExaminerLloyd L. King Assistant Examiner-R21ndolph A. Reese Attorney, Agent, or Fi'rm-Morsbach & Pillote ABSTRACT The mechanism is incorporated in a conveyor system of the type which propels vehicles, or pallets, by frictional contact between a rotating drive shaft and a drive wheel carried by the vehicle. The disclosed conveyor system includes two such rotating drive shafts and associated parallel tracks. The mechanism transfers the vehicles from one set of parallel tracks to the other via concentric tracks. An upright drive shaft drives a radially-extending pivoted arm on which is mounted an elongaged, arcuatemember. The member has a downwardly inclined ramp at its front to ride over any preceding vehicle, and a depending dog at its rear to engage the vehicle and advance it. A ramp raises the arm at the outlet of the concentric tracks to disengage the vehicle, and lowers the arm to operative position at the inlet thereof.

15 Claims, 7 Drawing Figures TRANSFER MECHANISM BACKGROUND The invention pertains to conveyor systems in which propulsion is achieved by traction between a drive wheel and a longitudinal rotary shaft, and more particularly to transfer mechanism for use in such a system.

One early patent disclosing a rotary drive shaft and a pair of traveling friction wheels engaged therewith at an angle to its axis, was issued May 7, 1889 to Whitecomb R. Judson, U.S. Pat. No. 402,674. This mechanical movement has been adapted for various uses including street railways (see US. Pat. No. 423,872 issued Mar. 18, 1890 to said Judson), and conveyor systems (see US. Pat. No. 3,356,040 issued Dec. 5, 1967 to Per Borje Fonden). Each of these latter two patents provided structure for switching" or turn-outs. Judson provided a plurality of short lengths of drive shaft connected by a type of universal coupling toprovide a generally curved drive shaft. Fonden provides drive shafts at right angles to each other, and stops the vehicle or truck prior to transfer to another drive shaft. It is desirable to provide a transfer mechanism which eliminates the Judson curved drive shaft, and which does not require stopping the vehicle prior to transfer.

The assignee of the present invention has, in the past, transferred vehicles or pallets from one drive shaft to a second spaced therefrom. The mechanism used sensed whether the second drive shaft'had room to accommodate a vehicle and was rendered inoperative unless there was such room. It is desirable to provide a transfer mechanism which eliminates such sensing apparatus. By doing so, it is possible to utilize the transfer pathway to store vehicles until room is available on the second drive shaft.

SUMMARY The present invention relates to a transfer mechanism for use in conveyor systems of the type having a longitudinal rotary drive shaft and a drive wheel frictionally engaged therewith.

It is an object of the present invention to provide a transfer mechanism for easily moving a pallet or vehicle into and/or out of position where it is driven by a rotary drive shaft.

Another object is to provide a transfer mechanism for use in a conveyor system of the type described which can store vehicles until room is available on the drive shaft.

Still another object of the present invention is to provide a transfer mechanism of simplified construction and which easily and effectively transfers vehicles from one rotary drive shaft to another.

Another object is to provide a transfer mechanism in accordance with the preceding object, and having an elongated member mounted on the end of a radiallyextending arm and which are driven to perform the transfer operation.

Yet another object is to provide mechanism in accordance with the preceding object and where the elongated member is mounted for movement between operative and inoperative positions.

These, and other objects and advantages of the present invention, will become apparent as the same becomes better understood from the following detailed description when taken in conjunction with the accompanying drawings. I

DRAWINGS FIG. 1 is a plan view of one end ofa machine incorporating the present invention, the other end being identical to the end illustrated;

FIG. 2 is a cross-sectional view taken generally along line 2--2 of FIG. 1;

FIG. 3 is a sectional view taken generally along line 3-3 of FIG. 2;

FIG. 4 is a top view, on an elongated scale, of the arcuate, elongate member mounted at the outer end of the arm;

FIGS. 5 and 6 are fragmentary elevations of the rear and front portions, respectively, of the arcuate, elongate member shown in FIG. 4, and on a still larger scale than FIG. 4; and

FIG. 7 is a cross-sectional view through the vehicle or pallet.

DESCRIPTION Reference is now made more particularly to the drawings which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the several views.

Referring to FIGS. 1 and 2, a machine indicated generally by the numeral 20 has two longitudinal, rotatable drive shafts 21 and 22 mounted parallel to each other. The drive shafts 21 and 22 are journaled in a plurality of spaced rollers 19, best shown in FIG. 2. The rollers are so located that the tops of the shafts are unobstructed for a purpose hereafter explained. A pair of spaced

tracks

23 and 24 are arranged parallel to shaft 21 to define a pathway along which vehicles V may move. A similar pathway is defined by another pair of spaced

tracks

25 and 26 which are arranged parallel to shaft 22. At the end of the tracks 23-26, is a transfer mechanism T associated with an inner arcuate track 27 which interconnects

tracks

24 and 25; and an outer arcuate track 28 which interconnects

tracks

23 and 26. Tracks 27 and 28 are preferably concentric and have a common are center for a purpose which will hereafter become apparent. At the other end of the machine is an identical transfer mechanism interconnecting the other ends of tracks 23-26. In this manner, the tracks form a definite trackway or pathway in the form of a closed loop conveyor.

A motor M is arranged to drive shaft 21 via a gear box 41 and

pulleys

42 and 43, as seen in FIG. 1. Identical structure at the other end of the machine is provided for driving shaft 22.

Referring particularly to FIG. 7, the pallet or vehicle V is provided with four wheels 51 which engage the upper side of the trackway, and four other wheels 56 mounted for rotation about a vertical axis to engage the inner edge of the rails 23-28 and prevent side sway of the vehicle as it is conveyed. Finally, four wheels (not shown) may be provided for engaging the bottom side of the tracks. In this manner, the pallets may be permanently mounted in the trackways with utmost stability.

Each pallet or vehicle V is provided with a freely rotatable driving wheel 67 which is pressed against the top of the driving shaft 21 or 22. Wheel 67 is rotatable mounted in a yoke 68 at the lower extremity of a shaft 69. Shaft 69 is rotatable mounted in

bearing

71 and 72 and the wheel 67 is pressed against the drive shaft by means of a compression spring 73 circumjacent shaft 69. A helical tension spring 74 exerts a force on the yoke 68 to resiliently urge the axis of rotation of the driving wheel 67 at an angle relative to the axis of rotation of the drive shaft, the drive wheel and drive shaft being so oriented that the drive wheel in the angular position thereof contacts the drive shaft along a horizontal tangent thereto. When the drive shaft 21 or 22 is rotated, the wheel 67 will roll against the drive shaft. When the axis of the wheel 67 is disposed at an angle, for example 35 to the axis of the drive shaft, the rotation of the latter produces a longitudinal force on the drive wheel. This longitudinal force is the driving force of the vehicle, and the drive wheel will follow a helical path along the drive shaft.

An outwardly extending arm 76 is connected to the yoke 68 and extends past the side of the pallet. The arm 76 is thus swingable with the drive wheel 67 and moves between a stop position in which the axis of drive wheel 67 is parallel to the axis of the drive shaft, and a drive position at an angle thereto as described above. Work stations (not shown) located along the conveyor system, may have stops for engaging the arm 76 and to move to the stop position. When the stop is removed, spring 74 will return the drive wheel 67 to the drive position and the vehicle V will be advanced away from the work station. A rearwardly extending arm 78 (see FIG. 1) is provided on each vehicle V to engage the arm 76 of a succeeding vehicle. In this manner, as two vehicles approach each other, collisions are prevented. An outwardly extending stub shaft 80 is provided on the inner side of the vehicle V at the longitudinal midpoint thereof and carries a roller 82 which is engaged by the transfer mechanism T.

Referring again to FIGS. 1 and 2, the transfer mechanism T is supported on a table 84 which, in turn, is supported by a plurality of tubular legs 86. An upright drive shaft 88, located at the common arc center, is mounted on the table 84 by means of an upper bearing 89 and has, at its lower end, another bearing 95 mounted in a stringer 91. A motor 94 drives the shaft 88 via a gear box 95 and

sprockets

96 and 97. At the upper end of shaft 88 is mounted a quadrifid member 98 which rotates when the shaft 88 is driven. A pair of outwardly-extending arms 100 are pivotally mounted on the member 98 by way of a pivot pin 102 having an axis extending crosswise of the arm. Two additional arms 100 could be mounted on the member 98 if desired. As a safety measure, the drive train can incorporate a slip clutch or torque limiting device arranged to operate when drive pressure exceeds a preselected amount.

An elongated arcuate member 104 is adjustably mounted at the outer end of each arm 100 by way of mounts 105 best shown in FIG. 4. The arcuate member 104 has an outer face 106 which is preferably disposed at an arc radially located from said common arc center, and an inner face 108 which is concentric therewith. Adjacent the front end of the arcuate member 104 is a downwardly inclined cam face 110 leading to a flat bottom side 112. Angle A in FIG. 6 is advantageously 7 30. At the rear edge of the arcuate member 104 is a recess 114 and a downwardly-extending dog 116 which depends almost to the level of bottom side 112. The dog 116 is mounted by a pivot pin 118 and a releasable retainer 120 which, as a safety measure, will allow the dog 116 to pivot when drive pressure becomes too great. In an alternate construction, dog 116 may be provided with a spring arrangement which allows an amount of give when the dog contacts the roller 82.

In operation, as the shaft 88 is rotated, the arms are swung and the arcuate member 104 moves through a circular path. When a vehicle is approached, cam face rides over the roller 82 disposed at the side of the vehicle V. The arm then pivots about pivot shaft 102 as the elongate member is cammed upwardly. The roller then rides on bottom face 112 and into recess 114 where it is engaged by dog 116. In this manner, the roller 82 serves as a catch and the dog 116 drives the vehicle V along the trackways. 27, 28 to the second drive shaft 22. Such transfer occurs unless a preceding vehicle is disposed in the trackway. In that event, the cam face 1 10 engages the roller 82 of thepreceding vehicle and disengages the roller 82 of the driven vehicle. For this purpose, the length of the lower face 112 is preferably at least equal to the length ofa vehicle. Thus it can be seen that the arcuate member 104 moves vertically between operative and inoperative positions.

Similar disengagement by upward movement of the arm 100 when the arcuate member 104 reaches a position adjacent shaft 22 is provided by additional mechanism. As shown in FIG. 3, arm 100 has a roller 122 mounted thereon outwardly of pivot pin 102, by means of an angle bracket 124. As the arm is swung, the roller 122 travels through a path 126 shown by phantom lines in FIG. 1. When the elongate member is in the vicinity of drive shaft 22, so that the drive shaft can then become operative for driving the vehicle V, the roller 122 engages an up-ramp 128 to ride up onto the upper surface of plates 131-133 mounted on the table 84. As shown in FIG. 1, plates 131-133 are arranged in a U- shaped configuration with their upper surfaces along path 126. Plate 133 is disposed adjacent drive shaft 21, and has a down ramp 134 positioned so that the dog 116 is moved from an inoperative position to an operative position to engage the wheel 82 of a vehicle V at the outlet of the

tracks

23 and 24. The positioning of this ramp is important since the circular path of the arcuate member 104 could bring it into an end-wise engagement with the outer end of shaft 80 and cause a jam up.

While a preferred embodiment of the invention has herein been illustrated and described, this has been done by way of illustration and not limitation, and the invention should not be limited except as required by the scope of the appended claims.

The embodiments of the invention in which an exclusive property of privilege is claimed are defined as follows:

l. A transfer mechanism for use in a conveyor system which includes a frame; first and second rotary drive shafts mounted on the frame in spaced relation to each other; means for rotating the rotary drive shafts; a first pair of tracks mounted parallel to the first rotary drive shaft; a second pair of tracks mounted parallel to the second rotary drive shaft; a pair of concentric, semicircular tracks interconnecting the first and second pair of tracks; a plurality of vehicles movably supported on the tracks; a drive wheel on each vehicle; and means mounting the drive wheel for engagement with the rotary drive shafts and at a position oblique to the axis of the rotary drive shafts to drive the vehicle as the rotary drive shafts are rotated; the transfer mechanism includan elongate member for engaging one of the vehicles;

drive means for driving the elongate member through a path concentric with the concentric tracks to 5 move the engaged vehicle therealong;

mounting means for mounting the elongate member for movement between an operative position engaged with the vehicle and an inoperative position removed therefrom; and the elongate member having means at its forward end for engaging a preceding vehicle and camming the elongate member to inoperative position;

whereby the vehicles are transferred from the first pair of tracks to the second pair of tracks unless a preceding vehicle is encountered by the elongate member.

2. A transfer mechanism as set forth in claim 1 wherein the mounting means mounts the elongate member for vertical movement and the inoperative position is at a level above the operative position.

3. A transfer mechanism as set forth in claim 2 wherein the concentric tracks have a common are center; the drive means includes a shaft having an axis at said arc center; and the mounting means includes an outwardly-extending arm to which the elongate member is secured, and a pivot axis cross-wise of the arm permitting swinging movement thereof in the vertical direction.

4. A transfer mechanism as set forth in claim 3 wherein the arm has a depending wheel mounted outwardly of said pivot axis for engaging the frame to position the elongate member at said operative position.

5. A transfer mechanism as set forth in claim 4 including ramp means on the frame for engagement by the depending wheel to raise the arm and elongate member to inoperative position when the vehicle reaches the second pair of tracks, and to return the arm and elongate member to operative position adjacent the first pair of tracks.

6. A transfer mechanism as set forth in claim 5 wherein:

the concentric tracks have a common are center;

the elongate member has an arcuate outer face, a I downwardly inclined cam face at its forward end for camming the elongate member to inoperative position, and a depending dog at its rear end;

the vehicle has a catch extending outwardly toward the arc center for engagement by the depending dog, the catch including a roller on which the cam face rides;

the drive means includes a shaft having an axis at the arc center; and

the mounting means includes a radially-extending arm to which the elongate member is secured, and a pivot axis crosswise of the arm permitting swinging movement thereof in the vertical direction.

7. A transfer mechanism as set forth in claim 2 in which the elongate member has a downwardly inclined cam face at its forward end for camming the elongate member to inoperative position.

8. A transfer mechanism as set forth in claim 7 wherein the vehicle has a catch extending outwardly therefrom toward the arc center, and on which the cam face rides; and the elongate member has a depending dog at its rear end for engaging the catch to move the vehicle.

9. A transfer mechanism as set forth in claim 1 wherein the elongate member has an arcuate outer surface, a cam face at its forward end for engaging a preceding vehicle and camming the elongate member to inoperative position, and a dog on the same side as the cam face for engaging the vehicle to advance it along the concentric tracks.

10. A transfer mechanism for use in a conveyor systern which includes a frame; an elongate rotary drive shaft having a smooth exterior and mounted on the frame; a pair of parallel tracks mounted parallel to the drive shaft; a plurality of vehicles movably supported on the tracks; a drive wheel on each vehicle; means mounting the drive wheel for engagement with the ro tary drive shaft and at a position oblique to the axis of the rotary drive shaft to advance the vehicle toward the outlet of the parallel tracks as the rotary drive shaft is rotated; and a pair of semicircular tracks having a common arc center and an inlet end connected to the outlet end of the parallel tracks; the transfer mechanism including:

a member having means for engaging a vehicle at the inlet end of the semicircular tracks;

a shaft having an axis at said are center;

a radially-extending arm operatively connected to the shaft and having an outer end to which the member is mounted, the arm having a crosswiseextending pivot axis intermediate its ends to permit swinging movement thereof in the vertical direction and, hense, movement of the member between an operative position engaged with the vehicle and an inoperative position raised therefrom; and

means for moving the member from the inoperative position to the operative position at the inlet end of the semicircular tracks to engage a vehicle and advance it along the semicircular tracks.

11. The combination of claim 10 in hich the member is elongated, has an outer face radially spaced from the common arc center, and at its forward end has a downwardly inclined cam face for engaging a preceding vehicle and camming the elongated member to its inoperative position.

12. The combination of claim lll in which the means for engaging a vehicle is located at the rear end of the elongated member, and the distance from said means to the cam face is at least as great as the length of a vehicle.

13. The combination of claim 11 in which the vehicle has a catch extending outwardly therefrom toward the arc center and on which the cam face rides; and the elongate member has a depending dog at its rear end for engaging the catch to advance the vehicle.

14. The combination of claim ll0 wherein the lastmentioned means includes a depending wheel on the arm and mounted outwardly of said crosswiseextending pivot axis.

15. The combination of claim 14 wherein the lastmentioned means includes a ramp on the frame for engagement by the depending wheel. l=

Claims

1. A transfer mechanism for use in a conveyor system which includes a frame; first and second rotary drive shafts mounted on the frame in spaced relation to each other; means for rotating the rotary drive shafts; a first pair of tracks mounted parallel to the first rotary drive shaft; a second pair of tracks mounted parallel to the second rotary drive shaft; a pair of concentric, semicircular tracks interconnecting the first and second pair of tracks; a plurality of vehicles movably supported on the tracks; a drive wheel on each vehicle; and means mounting the drive wheel for engagement with the rotary drive shafts and at a position oblique to the axis of the rotary drive shafts to drive the vehicle as the rotary drive shafts are rotated; the transfer mechanism including: an elongate member for engaging one of the vehicles; drive means for driving the elongate member through a path concentric with the concentric tracks to move the engaged vehicle therealong; mounting means for mounting the elongate member for movement between an operative position engaged with the vehicle and an inoperative position removed therefrom; and the elongate member having means at its forward end for engaging a preceding vehicle and camming the elongate member to inoperative position; whereby the vehicles are transferred from the first pair of tracks to the second pair of tracks unless a preceding vehicle is encountered by the elongate member.

3. A transfer mechanism as set forth in claim 2 wherein the concentric tracks have a common arc center; the drive means includes a shaft having an axis at said arc center; and the mounting means includes an outwardly-extending arm to which the elongaTe member is secured, and a pivot axis cross-wise of the arm permitting swinging movement thereof in the vertical direction.

6. A transfer mechanism as set forth in claim 5 wherein: the concentric tracks have a common arc center; the elongate member has an arcuate outer face, a downwardly inclined cam face at its forward end for camming the elongate member to inoperative position, and a depending dog at its rear end; the vehicle has a catch extending outwardly toward the arc center for engagement by the depending dog, the catch including a roller on which the cam face rides; the drive means includes a shaft having an axis at the arc center; and the mounting means includes a radially-extending arm to which the elongate member is secured, and a pivot axis crosswise of the arm permitting swinging movement thereof in the vertical direction.

10. A transfer mechanism for use in a conveyor system which includes a frame; an elongate rotary drive shaft having a smooth exterior and mounted on the frame; a pair of parallel tracks mounted parallel to the drive shaft; a plurality of vehicles movably supported on the tracks; a drive wheel on each vehicle; means mounting the drive wheel for engagement with the rotary drive shaft and at a position oblique to the axis of the rotary drive shaft to advance the vehicle toward the outlet of the parallel tracks as the rotary drive shaft is rotated; and a pair of semicircular tracks having a common arc center and an inlet end connected to the outlet end of the parallel tracks; the transfer mechanism including: a member having means for engaging a vehicle at the inlet end of the semicircular tracks; a shaft having an axis at said arc center; a radially-extending arm operatively connected to the shaft and having an outer end to which the member is mounted, the arm having a crosswise-extending pivot axis intermediate its ends to permit swinging movement thereof in the vertical direction and, hense, movement of the member between an operative position engaged with the vehicle and an inoperative position raised therefrom; and means for moving the member from the inoperative position to the operative position at the inlet end of the semicircular tracks to engage a vehicle and advance it along the semicircular tracks.

12. The combination of claim 11 in which the means for engaging a vehicle is located at the Rear end of the elongated member, and the distance from said means to the cam face is at least as great as the length of a vehicle.

14. The combination of claim 10 wherein the last-mentioned means includes a depending wheel on the arm and mounted outwardly of said crosswise-extending pivot axis.

15. The combination of claim 14 wherein the last-mentioned means includes a ramp on the frame for engagement by the depending wheel.