US3265207A

US3265207A - Lumber sorting mechanism

Info

Publication number: US3265207A
Application number: US392437A
Authority: US
Inventors: Joseph M Lawson
Original assignee: Moore Dry Kiln Co
Current assignee: Coe Manufacturing Co
Priority date: 1964-08-27
Filing date: 1964-08-27
Publication date: 1966-08-09
Anticipated expiration: 1983-08-09
Also published as: ES316818A1; NL6511149A

Description

2 Sheets-Sheet 1 INVENTOR. JOSEPH M. LAWSON W K W J. M. LAWSON LUMBER SORTING MECHANISM Aug. 9, 1966 Filed Aug. 27, 1964 J. M. LAWSON Aug. 9, 1966 LUMBER SORTING MECHANISM 2 Sheets-Sheet 2 Filed Aug. 27, 1964 0 MW km United States Patent Office Meme, A

3,265,207 ugust 9, 1966 Filed Aug. 27, 1964, Ser. No. 392,437 7 Claims. (Cl. 209-106) This invention relates to mechanisms for use in sorting boards of lumber, and particularly relates to that type of sorting mechanism in which the boards are moved lengthwise.

A primary object of the present invention is to provide a lumber sorting mechanism of the above-mentioned type which can be run at much higher speeds than pre vious mechanisms of this general type, as for example, at speeds 100% higher than others.

A further object is to provide a unique lumber sorting mechanism that relies on gravity to move the selected boards out of the line of travel of the other boards, thereby eliminating the necessity of the mechanical devices, etc. of other machines to move the selected boards out of the line of travel, which mechanical devices limited the speed of the machines.

A further object of the present invention is to provide a substantially simple and durable mechanism for positively and accurately sorting boards according to length.

A further object of the present invention is to provide lumber sorting mechanism suitable for use in combination with the machinery of a saw mill or as a separate machine.

A further object is to provide lumber sorting mechanism suitable for use as combination lumber sortingconveying means and such mechanism as may be readily constructed for sorting out and depositing the boards at a plurality of widely spaced stations or locations.

A further object is to provide, in lumber sorting mechanism of the present invention, lumber sorting means readily applicable in the construction of devices of varions sizes or capacities.

A further object is to provide lumber sorting mechanism which is easy to operate and maintain and in which the operation and maintenance thereof requires no special skill or attention by the operator.

A further object is generally to improve the design and construction of lumber sorting devices.

The means by which the foregoing and other objects of the present invention are accomplished and the manner of their accomplishment will be readily understood from the following specification upon reference to the accompanying drawings, in which:

FIG. 1 is a front elevational view of the device of the present invention shown broken and offset for clarification purposes and with the boards being sorted shown in broken lines.

FIG. 2 is a plan view of the machine of FIG. 1.

Referring now to the drawings in which the various parts are indicated by reference characters, there is illustrated a complete machine, indicated as at 11, which includes motor means, indicated as at 13. It should be understood, however, that the mechanism of the present invention is suitable for use either in combination with the machinery of a saw mill or as a complete self-powered machine as shown; and also the mechanism of the present invention is adapted to be readily applicable in the construction of devices having many sorting stations and such stations as could be arranged along both sides of the device. In the following portions of the specification, however, for clarification purposes, the invention will be illustrated and described in the embodiment of machine 11, wherein the sorting stations are arranged substantially close together and along only one side of the machine.

Machine 11 includes a long horizontally-disposed frame 15 which includes a forward end, indicated at 17, and a rearward end, indicated at 19. Frame 15 preferably includes two

horizontal members

21, 23 of hollow box-girder material and extending the length of the machine.

Members

21, 23 are secured in spaced and parallel relationship by a plurality of

cross-members

25, 27, 29 and 31. A plurality of legs 33 are subjacently attached as by welding respectively

horizontal members

21, 23.

In operation, the boards B are moved fiat and endwise along horizontal member 21 of the machine and from the forward to the rearward end of frame 15. In other words, this is a flat board sorter in which the boards are moved endwise with the boards being disposed horizontally, as opposed to an edge sorter in which the boards are supported on an edge and disposed generally vertically or at a slight angle relative to the vertical. Guide means, included in frame 15, engage a vertical edge surface S of each board. The vertically disposed outward side wall surface 35 of horizontal member 21 preferably constitutes the guide means of machine 11.

A plurality of sorting stations 37 are arranged successively along frame 15 with each of the stations being adapted to sort out a certain length board. Each of stations 37 includes a first roller 39 and a second roller 41. The length of

rollers

39, 41 is each preferably commensurate with the width of the widest of boards B anticipated to be sorted. The inwardly disposed end of each of

rollers

39, 41 is journaled at respective station locations along horizontal frame member 21 for rotation of the rollers about substantially horizontal axes that are substantially parallel. An angle iron support member 43 and post 15 support the outwardly disposed end of each of rollers 39, 4-1. The outer end of the first and second rollers are journaled respectively in the end portions of the upright flanges of the respective support members 43. The distance between the first and second rollers 39, 4-1 substantially determines the length of the boards sorted out at a particular station, as will be more clearly understood later in the specification. First and

second rollers

39, 41 respectively rollably engage the undersurface of the boards.

Support means is secured to frame 15 and disposed substantially between first and

second rollers

39, 41. The support means includes a shelf-like support structure 47 which extends horizontally and outwardly from the vertically disposed wall surface 35' of horizontal member 21. Support structure 47' is preferably of flat strap or bar material and extends longitudinally and horizontally along frame member 21 and is fixedly attached thereto as by welding along the inward edge thereof. The outward extension of support structure 47 from the vertical wall surface of member 21 is materially less than the outward extension of each of

rollers

39, 41. The outward extension of support structure 47 is preferably less than one-half the width of the narrowest board to be sorted by the machine 11. The upper surface of structure 47 is adapted to supportably engage that portion only of the undersurface of a board adjacent the inward edge S of the board, i.e., that board edge slidably engageable with the vertically disposed wall surface 35 of frame member 21. A board being sorted is thus adapted to be moved flat and endwise along frame 15 with the inwardly disposed edge surface S slidably engaging the guide means or the outward side surface 35 of member 21. When a board reaches a sorting station 37 having sufficient spacing between the first and

second rollers

39, 41 to accommodate the length of the board, it will fall between the rollers and be accepted at that station.

Feed wheel means is provided for moving boards B along frame member 21. The feed wheel means prefer- .ably includes a first feed wheel 49 and a second feed wheel 51 which are adapted to rollably engage respectively the upper surfaces of the boards. First and

second feed wheels

49, 51 of each station 37 are preferably mounted respectively directly over first and

second rollers

39, 41. The feed wheels are skewed convergingly toward surface 35 of frame member 21 and toward the rearward end 19 of the frame, with the axes remaining in a horizontal plane. Feed

wheels

49, 51 are skewed for the purpose of holding the edge surfaces S of the boards in sliding engagement with the vertical surface 35 of frame member 21 as the boards are moved endwise along the frame. Drive means drivably connect the first and second feed wheels for the actuation thereof and for the movement of the boards. Further description of the drive means will be given later in the specification; however, for clarification purposes, the disposition or relative arrangement of sorting stations 37 will first be described.

It is readily apparent from the drawings that the feed wheels and rollers of adjacent stations are mounted respectively in pairs, that is, a second feed wheel of a station is mounted in conjunction or paired with a fifth feed wheel of a succeeding station, and a second roller of a station is mounted in conjunction or paired with a first roller of a succeeding station. Moreover, it is further apparent that the first feed wheel and roller at forward end 17 of frame and the last feed wheel and roller at rearward end 19 of the frame are not components of a sorting station. Such components will be designated auxiliary feed wheels 53 and rollers 55. The sorting stations illustrated in machine 11 are arranged somewhat close together, which renders it practical to mount a respectlve feed wheel and roller of adjacent sorting stations in pairs. It is not intended or contemplated, however, that the arrangement of the wheels and rollers in pairs is the most practical construction in all embodiments of the present invention. In certain constructions, it is desirable to place the sorting stations a considerable distance apart. In a construction as this, the paired arrangement of wheels and rollers, as in machine 11, would be applicable, but the forwardly disposed wheel and roller at each stat-ion would then be an auxiliary wheel 53 and an auxiliary roller 55 and would be as that shown at the forward end of machine 11; and that paired arrangement of wheels and rollers rearward of the respective sorting station would include rearwardly disposed auxiliary feed wheels and rollers and be as that shown at rearward end 19 of machine 11. In such constructions wherein there is considerable distance between the sorting stations, several auxiliary wheels 53 and rollers 55, either mounted singly or in pairs, are mounted between the spaced stations and serve principally to convey the boards from one station to the following station. For purposes of description and clarification, however, the mechanism of the present invention will be described in the embodiment of machine 11, which has substantially closely spaced sorting stations and wherein a first feed wheel and roller of a station are preceded by and mounted in conjunction with the second feed wheel and roller of a preceding station.

In machine 11, the paired mounting of a first wheel and roller of a station with the second wheel and roller of a preceding station is preferably as follows: The respective first and second rollers of the two stations are spaced apart somewhat and are journaled by suitable means to frame member 21 and angle iron support member 43. Support member 43 provides common support means for the outward ends of the respective first and second rollers which are journaled respectively in the rearward and forward end portions of the support member. A plurality of rollers, as rollers 57, are preferably intermediately arranged between first and

second rollers

39, 41. Rollers 57 are mounted as are the first and second rollers of the two stations and supportingly engage the undersurface of the boards. The first and second feed wheels are respectively journaled in the oppositely disposed end portions of a bar member 59 which, in turn, is movably mounted from horizontal frame member 21. Bar member 59 is preferably formed of fiat plate material and is of a length somewhat longer than the distance between the respective first and second wheels and rollers. Two pairs of upright guide members are provided and include a forwardly disposed pair of members 61 and a rearwardly disposed pair of members 63. Each pair of upright members 61, 63 is secured in spaced and parallel relationship from frame member 21. The paired members 61, 63 are preferably fixedly secured as by welding at the lower ends thereof to the upper surface 65 of frame member 21. Bar member 59 is received in and adapted to be guided in vertical movement by upright guide members 61, 63.

Axles

67, 69 and

bearings

71, 73 respectively journal first and

second feed wheels

49, 51 from bar member 59. Each of

bearings

71, 73 includes two bearing halves which are attached by suitable means, not shown, to the oppositely disposed side surfaces of bar member 59. The two bearing halves of each bearing 71, 73 are preferably of the self-aligning, flange-mount type. The self-aligning feature-of the bearing halves permits the

respective axles

67, 69 and thus feed

wheels

49, 51 to be skewed slightly, with the axes remaining horizontal. The disposition of the feed wheels with reference to frame member 21 should be such that, when viewed vertically and as shown in FIG. 2, the inward side surface of a respective feed wheel should be substantially close to the vertically disposed outside edge 35 of frame member 21. The rim portion of each

wheel

49, 51 is preferably of resilient material to provide the desired frictional characteristics for the movement of the boards. A tension bar 75 and bracket 77 secure and stabilize bar member 59 in the respective upright guide members 61, 63. Each bracket 77 preferably includes an aligned pair of apertured bracket halves fixedly attached as by welding respectively to the oppositely disposed side surfaces of bar member 59 and extending upwardly therefrom. Aligned apertures are provided in the upper portions of each of upright guide members 61. Pins 79, 81, extending respectively through the oppositely disposed end portions of bar member 59 and respectively through upright guide members 61 and brackets 77, movably secure the bar member from frame 15. Stop means is provided for limiting the downward movement of bar member 59 and

feed wheels

49, 51. The stop means preferably includes a pair of stop screws 83 threadedly secured respectively in the oppositely disposed end portions of bar member 59. The ends of stop screws 83 respectively engage the upper surface 65 of frame member 21.

The drive means for the actuation of first and

second feed wheels

49, 51 preferably is as follows: First and

second sheaves

85, 87 are fixedly secured to the inward end portions of the

respective axles

67, 69. Each of

sheaves

85, 87 is provided with a semi-circular surfaced groove extending circumferentially therearound. A dualgrooved drive sheave 89 fixedly secured to axle 91 is mounted in bearings 93 at the rearward end 19 of frame 15. An electric motor 95 is securely mounted from frame 15. Suitable power transmission means, designated generally at 97, connects motor 95 with axle 91 and rotates drive sheave 89. A long round-sectioned belt or endless cable 99 encircles drive sheave 89 and is drivably connected with the

respective sheaves

85, 87. Cable 99 extends substantially one and one-half times around drive sheave 89 for preventing the cable from slipping on the sheave. Cable 99 extends through a pulley 101 which is secured by a threaded fastener 103 to frame cross-member 29. A portion of cable 99 which encircles drive sheave 89 extends through pulley 101. The pulley is canted somewhat from a vertical position and serves principally to transfer the cable from one of the grooves of dualgrooved drive sheave 89 to the other groove therein. A pulley 105 is positioned at the forward end of frame 15.

Cable 99 extends through pulley 105 and includes a lower span 107 and an upper span 109.

As viewed in FIG. 1, it is apparent that cable 99, feed

wheels

49, 51, and the respective sheaves and pulleys all move generally in a counterclockwise direction. This, of course, turns the respective feed wheels in the right direction to urge boards B from the forward end to the rearward end of frame 15. The lower span 107 of cable 99 extends substantially straight and uninterruptedly from drive sheave 89 to pulley 105. Upper span 109 includes three loops which drivably encircle respectively the three paired sheaves. With reference to FIG. 1 and considering that the cable of upper span 109 moves to the right and toward the rearward end of frame 15, the arrangement of cable 99 around the sheaves at each loop is such that the cable extending upwardly and rearwardly from pulley 105 extends over and around sheave 85, forwardly and across to sheave 87, under and around sheave 87, and rearwardly to the next loop around the following paired sheaves.

Alignment pulleys 111 are located at strategic locations to align and correctly guide cable 99 in the respective grooves of

sheaves

85, 87. Pulley 105 is preferably yieldably mounted from frame 15. This mounting preferably includes a helical tension spring 113 secured to pulley 105 on one end and to an adjustable threaded fastener 115 at the oppositely disposed end. Threaded fastener 115 extends through cross-member 25 and is adjustable for regulating the tension of cable 99.

A table 117 is preferably provided at the forward end of machine 11 and serves principally to support the boards as they are graded or selected by the operator and to initially align the boards as they are fed into the machine. Board collection means is preferably provided at each of sorting stations 37. The collection means at each station preferably includes support timbers 119 and slides 121. Timbers 119 rests on the ground and are disposed substantially perpendicularly of frame 15. Slides 121 extend obliquely upwardly from an inward end of each of support timbers 119 and are secured at the upper end thereof to horizontal frame member 21.

The sorting stations of the lumber sorting mechanism are constructed and arranged so that the first station at the forward end of the device is adapted to sort out the shorter boards, and the succeeding stations to sort out progressively longer boards. The first station at the forward end of the machine sorts out boards under a certain length of all the boards sorted by the machine. The second or next succeeding station is adapted to sort out boards of a length between the maximum acceptable length of the first station and the somewhat longer maximum acceptable length of the second station. All -of the following stations are adapted to sort out boards as does the second station and in progressively longer lengths. A board which is too long to be accepted at a station will be supported simultaneously by the first and second roller members of that station and will be moved further along until it reaches the first station that will accept the board.

A board shorter than the distance substantially between the first and second roller members of a station will be accepted or sorted out at that station. A board of a length to be acceptable at a certain station moves between the first roller and first feed wheel of that station and slidably along the support structure thereof. As the support structure engages only the undersurface of the board adjacent the inwardly disposed edge thereof, when the board is moved on past the first feed wheel and roller, the outwardly disposed edge of the board will drop off in a downwardly direction. The forward end edge of the board will then drop below or abuttingly engage the second roller of that station, and the board will slide down slide members 121 and onto the support timbers 119.

Stop screws 83 should be adjusted in accordance with the thickness of the boards being sorted. Thus, stop screws 83 adjustably determine the vertical distance between the respective feed wheels and roller members when no board is disposed therebetween. When screws 83 are correctely adjusted, the respective feed wheels will be allowed to drop low enough to exert sufficient frictional contact with the boards for movement thereof, but will not permit the wheels to drop so low as to roughly engage the board ends as the boards move under the wheels.

The lumber sorting mechanism of the present invention is easy to operate and requires very little maintenance. The mechanism is readily applicable in the construction of lumber sorting devices of various sizes and capacities. It is substantially simple and durable. In summary, the present invention provides very practical means for quickly and accurately sorting lumber according to the length of the boards.

Although the invention has been described in some detail by way of illustration and example for purposes of clarity or understanding, it is to be understood that it is not to be so limited since changes and modifications may be made therein which are within the full intended scope of this invention as hereinafter claimed.

I claim:

1. A machine for sorting boards according to length as the boards are moved flat and endwise along the machine comprising a long frame disposed horizontally, guide means included in and extending horizontally and rectilinearly along a side of said frame and engageable with a vertical edge surface of each board, and a plurality of sorting stations disposed successive-1y along said frame with each said station being adapted to sort out a certain length board; each of said sorting stations comprising roller means secured to said frame and extending horizontally and outwardly from said side of said frame, said roller means including a first roller member and a second roller member, said roller members being rollably engageable with the undersurface of the boards, support means secured to said frame and disposed substantially between saidfirst and second roller members, said support means including support structure extending horizontally and outwardly from said side of said frame, said support means being supportably engageable with that portion of the undersurface of the boards adjacent and longitudinally intersecting the above-mentioned vertical edge surfaces thereof, and motor driven feed wheel means mounted from said frame and rollably engageable with the upper surface of the boards, said feed wheel means including a first feed wheel and a second feed wheel mounted respectively above said first and second roller members, the length of a board sorted out at a respective station of said plurality of stations being determined by the distance between said first roller member and said second roller member.

2. A machine for sorting boards according to length as the boards are moved flat and endwise along the machine comprising a long frame disposed horizontally, guide means included in and extending horizontally and rectilinearly along a side of said frame and engageable with a vertical edge surface of each board, and a plurality of sorting stations disposed successively along said frame with each said station being adapted to sort out a certain length board; each of said sorting stations comprising roller means secured to said frame and extending horizontally and outwardly from said side of said frame, said roller means including a first roller member and a second roller member, said roller members being rollably engageable With the undersurface of the boards, support means secured to said frame and disposed substantially between said first and second roller members, said support means including support structure extending horizontally and outwardly from said side of said frame, said support means being supportably engageable with that portion of the undersurface of the boards adjacent and longitudinally intersecting the above-mentioned vertical edge surfaces thereof, and motor driven feed wheel means mounted from said frame and rollably engageable with the upper surface of the boards, said feed wheel means including a first feed wheel and a second feed wheel mounted respectively above said first and second roller members, the axes of rotation of said first and second feed wheels each being skewed horizontally slightly toward said guide means relative to the direction of movement of the boards, the length of a board sorted out at a respective station of said plurality of stations being determined by the distance between said first roller member and said second roller member.

3. The machine of claim 2 in which the extension of said support structure is less than one-half the width of the narrowest board to be sorted by the machine.

4. The machine of claim 2 in which the mounting of said motor driven feed wheel means from said frame includes means whereby a first said wheel and a first said roller member of a station is preceded by and mounted in conjunction with a second said wheel and a second said roller member of the preceding station defined with reference to the direction of movement of the boards along the machine.

5. A machine for sorting boards according to length as the boards are moved flat and endwise along said machine comprising a long frame disposed horizontally and having a forward end and a rearward end,

guide means included in and extending horizontally and rectilinearly along a side of said frame and engageable with a vertical edge surface of each board, and a plurality of sorting stations arranged successively along said frame, each of said stations being adapted to sort out a certain length board; each of said sorting stations comprising a first roller member, a second roller member, said first and second roller members being secured to said frame and extending longitudinally and outwardly from said side thereof, said first and second roller member being rollably engageable with the undersurface of the boards, support means secured to said frame and disposed substantially between said first and second roller members, said support means including support structure extending horizontally and outwardly from said side of said frame and with the extension of said support structure being less than the extension of said first and second roller members, said support means being supportably engageable with that portion of the undersurface of the boards adjacent and intersecting the abovementioned vertical edge surfaces thereof, and motor driven feed wheel means mounted from said frame and rollably engageable with the upper surface of the boards, said feed wheel means including a first feed wheel and a second feed wheel mounted respectively above said first and second roller members, said first and second feed wheels each being skewed horizontally and convergingly toward said guide means and toward said rearward end of said frame, the length of a board sorted out at one of said plurality of stations being determined by the distance between said first roller member and said second roller member, and the first station of said plurality of stations at said forward end of said frame being adapted to sort out the shorter boards and the succeeding stations being adapted to sort out progressively longer boards.

6. A machine for sorting boards according to length as the boards are moved flat and endwise along said machine comprising a long frame disposed horizontally and having a forward end and a rearward end, guide means included in and extending horizontally and rectilinearly along the side of said frame and engageable with a vertical edge surface of each board, and a plurality of sorting stations arranged successively along said frame, each of said sorting stations being adapted to sort out a certain length board; each of said sorting stations comprising a first roller member, a second roller member, said first and second roller members being secured to said frame and extending horizontally and outwardly from said side thereof, said first and second roller member being rollably engageable with the undersurface of the boards, support means secured to said frame and disposed substantially between said first and second roller members, said support means including support structure extending horizontally and outwardly from said side of said frame and with the extension of said support structure being less than one-half the width of the narrowest board to be sorted by the machine, said support means being supportably engageable with that portion of the undersurface of the boards adjacent and intersecting the above-mentioned vertical edge surfaces thereof, a first feed wheel, a second feed wheel, means mounting said first and second feed wheels from said frame and respectively above said first and second roller members, and drive means drivably connected with said first and second feed wheels for the actuation thereof, said first and second feed wheels each being skewed convergingly toward said guide means and toward said rearward end of said frame, the length of a board sorted out at a station being determined by the distance between said first roller member and said second roller member, and the first station of said plurality of stations at said forward end of said frame being adapted to sort out the shorter boards and the succeeding stations to sort out progressively longer boards.

7. The machine of claim 6 in which said means mounting said first and second feed wheels from each station of said plurality of stations includes means whereby said first and second feed wheels are vertically movable at variable distances from the respective said first and second roller members for the sorting of boards of various thicknesses.

References Cited by the Examiner UNITED STATES PATENTS 2,365,822 12/1944 Jones 209-106 2,901,106 8/1959 Aitken 209103 ROBERT B. REEVES, Primary Examiner.

J. N. ERLICH, Assistant Examiner.

Claims

1. A MACHINE FOR SORTING BOARDS ACCORDING TO LENGTH AS THE BOARDS ARE MOVED FLAT AND ENDWISE ALONG THE MACHINE COMPRISING A LONG FRAME DISPOSED HORIZONTALLY, GUIDE MEANS INCLUDED IN AND EXTENDING HORIZONTALLY AND RECTILINEARLY ALONG A SIDE OF SAID FRAME AND ENGAGEABLE WITH A VERTICAL EDGE SURFACE OF EACH BOARD, AND A PLURALITY OF SORTING STATIONS DISPOSED SUCCESSIVELY ALONG SAID FRAME WITH EACH SAID STATION BEING ADAPTED TO SORT OUT A CERTAIN LENGTH BOARD; EACH OF SAID SORTING STATIONS COMPRISING ROLLER MEANS SECURED TO SAID FRAME AND EXTENDING HORIZONTALLY AND OUTWARDLY FROM SAID SIDE OF SAID FRAME, SAID ROLLER MEANS INCLUDING A FIRST ROLLER MEMBER AND A SECOND ROLLER MEMBER, SAID ROLLER MEMBERS BEING ROLLABLY ENGAGEABLE WITH THE UNDERSURFACE OF THE BOARDS, SUPPORT MEANS SECURED TO SAID FRAME AND DISPOSED SUBSTANTIALLY BETWEEN SAID FIRST AND SECOND ROLLER MEMBERS, SAID SUPPORT MEANS INCLUDING SUPPORT STRUCTURE EXTENDING HORIZONTALLY AND OUTWARDLY FROM SAID SIDE OF SAID FRAME, SAID SUPPORT MEANS BEING SUPPORTABLY ENGAGEABLE WITH THAT PORTION OF THE UNDERSURFACE OF THE BOARDS ADJACENT AND LONGITUDINALLY INTERSECTING THE ABOVE-MENTIONED VERTICAL EDGE SURFACES THEREOF, AND MOTOR DRIVEN FEED WHEEL MEANS MOUNTED FROM SAID FRAME AND ROLLABLY ENGAGEABLE WITH THE UPPER SURFACE OF THE BOARDS, SAID FEED WHEEL MEANS INCLUDING A FIRST FEED WHEEL AND A SECOND FEED WHEEL MOUNTED RESPECTIVELY ABOVE SAID FIRST AND SECOND ROLLER MEMBERS, THE LENGTH OF A BOARD SORTED OUT AT A RESPECTIVE STATION OF SAID PLURALITY OF STATIONS BEING DETERMINED BY THE DISTANCE BETWEEN SAID FIRST ROLLER MEMBER AND SAID SECOND ROLLER MEMBER.