US3627000A

US3627000A - Combination flyback curtain and snubber for ripsaw machines and the like

Info

Publication number: US3627000A
Authority: US
Inventors: Lloyd George Alden
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-11-05
Filing date: 1969-11-05
Publication date: 1971-12-14
Anticipated expiration: 1988-12-14

Abstract

Downwardly biased relatively sharp-tipped fingers are pivotally mounted in a curtain row across the infeed end portion of a powered ripsaw machine table, with upper end shoulders on the fingers normally separably engaging a stop bar but permitting forward passage swinging of those fingers of which the tips are contacted by a piece of lumber during infeed.

Description

United States Patent Inventor Lloyd George Alden, deceased late of Plainlleld, III. by Verna R. Alden, executrix, 804 Barlett, Plainfield, I11. 60544,

Appl. No. 874,104

Filed Nov. 5, I969 Patented Dec. 14, 1971 COMBINATION FLYBACK CURTAIN AND SNUBBER FOR RIPSAW MACHINES AND THE LIKE I I Claims, 4 Drawing Figs.

U.S. C1 143/159 C Int. Cl 827g 19/02 Field of Search 143/159 C,

[56] References Cited UNITED STATES PATENTS 1,681,832 8/1928 Wulf 143/159 C 1,368,773 2/1921 Voss et a1. 143/159C 3.534,790 10/1970 Thrasher 143/159 C Primary ExaminerDonald R. Schran An0rney Hill, Sherman, Meroni, Gross & Simpson ABSTRACT: Downwardly biased relatively sharp-tipped fingers are pivotally mounted in a curtain row across the infeed end portion of a powered ripsaw machine table, with upper end shoulders on the fingers normally separably engaging a stop bar but permitting forward passage swinging of those fingers of which the tips are contacted by a piece of lumber during infeed.

Patented Dec. 14, 1971 3,62 @511 2 Sheets-Sheet 2 COMBINATION FLYBACK CURTAIN AND SNUBBER FUR RIPSAW MACHINES AND THE LIKE This invention relates to a safety device especially suitable for powered ripsawmachines and the like and is more particularly concerned with a combination flyback curtain and snubber device.

A problem encountered with production power machines adapted for acting on lumber, such as industrial ripsaw machines of the kind employed, for example, in furniture factories to rip large pieces of lumber or timbers into smaller pieces, resides in the liability of knots or other hard obstructions or foreign material such as nails to cause the saw blades to eject the piece of lumber violently rearwardly and if the lumber is shattered for any reason to fling pieces rearwardly at dangerous velocity. It is to meet this problem in a reliable and efficient manner that the present invention is directed.

An important object of the present invention is to provide a new and improved safety device for the feed-in areas of power operated lumber processing machines such as ripsaws.

Another object of the invention is to provide a novel combination flyback curtain and snubber device for ripsaw machines and the like.

Another object of the invention is to provide a new and improved, positively acting, highly reliable and efiicient safety finger array for production lumber processing machines such as ripsaws.

Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:

FIG. I is a perspective view of a ripsaw machine embodying features ofthe present invention;

FIG. 2 is a fragmentary perspective view showing a front view of the safety curtain and snubber;

FIG. 3 is an enlarged end elevational view of the safety curtain and snubber device; and

FIG. 4 is a fragmental rear elevational view of the device.

By way of example of an important use for a combination flyback curtain and snubber 5 embodying features of the invention, a power ripsaw machine 7 is depicted in FIG. I. Such a machine includes a work table 8 upwardly through which extend rotary ripsaw blades 9 cooperating with overhead rotary ripsaws III. with feed-in rollers II acting on pieces of lumber fed in across the rear end portion of the table 8 to drive the pieces into the ripsaw blades to trim and subdivide the lumber pieces longitudinally. Power may be supplied by an electrical motor I2 on the machine. Vertical adjustments of the table 8 may be effected through a gearing system operated by a crank handle 113. On the table is mounted an adjustable lumber guiding bar 114.

Operation of the ripsaw blades 9 and I is effected at high speed and with relatively high power input, depending, of course, upon the size and grade of lumber to be processed, to the extent that the motor 12 may be rated up to as high as I00 horsepower. Consequently, a real hazard exists in the operation of the machine that ifa hard knot, nail or other relatively resistant area or matter is encountered by the saw blades a piece of lumber may be precipitately thrust rearwardly with considerable force, or may even be shattered with pieces flung rearwardly with considerable velocity, in spite of and past the rearmost feed rollers II. It is to the elimination of this hazard that the present invention is directed. To this end, the device comprises an array of pivotally mounted downwardly biased relatively sharp-ended antikickback safety fingers I5 extending as a curtain row over and across the rear end portion ofthe table 8 in a manner to enable a piece or more of planking or lumber, generally referred to herein as lumber L, to be fed freely into the machine (FIG, 2) but acting positively to prevent rearward ejection of the lumber as a piece or shattered pieces thereof.

Each of the fingers I5 is so constructed and arranged that it will afford maximum resistance to deformation in a front to rear direction while nevertheless permitting free passage of lumber of various widths with unengaged fingers lying closely along one or both sides of the piece of lumber so that there is minimum gap alongside the lumber. To this end, each of the fingers 15 is constructed as a relatively flat downwardly tapered bar made of a suitable material such as steel, with the finger plane extending in front to rear direction such that the broad faces of the fingers are in confronting relation in the row. At their upper wider head end portions, considered in a front to rear direction, the fingers 15 are pivotally mounted on a shaft 17 with relatively thin spacer washers I8 between the head end portions for complete freedom of relative pivotal swinging movement of the fingers on the shaft. Along their rear edges the fingers are provided with respective smooth downwardly and forwardly oblique cam surfaces nineteen to facilitate passage of the leading end of a lumber piece into engagement and past the engaged fingers. Further, construction of the fingers is such that the center of weight is forwardly from a vertical longitudinal plane through the shaft 17 whereby to assure downward gravity bias of the fingers to depend from the shaft and to avoid the necessity for biasing springs, although if preferred, biasing springs could be used. At their lower ends the fingers are provided with generally forwardly directed substantially chisel edges 20 adapted to dig in and snubbingly retain the lumber piece L should it be thrust rearwardly. Efficiency of the chisel edges 20 is enhanced by intennediately notching out each of the edges as shown at 21 whereby to subdivide each edge into two short edge sections (FIG. 4).

In order to .hold the fingers 15 against backing away from snubbing position and to hold those fingers I5 which are serving as protective curtain against being swung rearwardly from safety curtain position, each of the fingers has on the upper rear portion of its head end a stop shoulder 22 which is separably engageable with a backup safety stop bar 23 fixedly mounted on the shaft I7 over and across the head ends of the fingers. In order to facilitate assembly of the fingers and the washers I8 onto the shaft, the bar 23 is desirably mounted separably as by means of spacer blocks 24 at the respective opposite end portions of the bar seated on suitable respective flat milled seats 25 on the shaft and secured by means of bolts 27 extending through the end portions of the bar and the spacer blocks 24 into tapped bores 28 in the shaft. The arrangement is such that the stop bar 23 adequately overlies the shoulders 22 (FIG. 3) to provide positive step engagement therewith.

Mounting of the shaft I7 on the machine is desirably effected in a manner to enable preferred adjustment of the assembly to attain the utmost protective value from the fingers 115. To this end at least one end portion of the shaft 17 is en gaged adjustably in a bracket 29 comprising an elongated block having therein a bore 30 closely slidably receptive of an end portion of the shaft which is provided with a shallow annular groove 31 into which a setscrew 32 extending in from the adjacent end of the block 29 engages retainingly. Thereby adjustment of the shaft 17 rotatably is enabled in the block 29 as indicated in dot-dash outline in FIG. 3. The groove 31 prevents interference with free movement of the shaft into and out of the closely dimensioned bore 30 should the setscrew 32 gouge the surface of the shaft engaged thereby in retaining the shaft in any preferred adjusted attitude of the supported fingers and stop bar assembly. It will be appreciated that in FIG. 3 the relative illustrated range of positions of the shaft and is carried assembly with respect to the bracket bar 29 have been substantially exaggerated for illustrative purposes and that in practical sense the adjustments may be less in extent to meet optimum working relationships.

Mounting of the bracket member 29 on the machine is desirably effected in a manner to enable vertical adjustments of the finger assembly relative to the table 8. To this end, the bracket member 29 comprises a solid block which is horizontally intermediately slotted inwardly from one end as shown at 33 such that by means of a bolt 34 the separated forward end ortions of the bracket member are adapted to be clamped retainingly onto a stub shaft 35 rigid with the machine frame and projecting through a suitable transverse bore 37 in the bracket bisected by the slot 33. Through this arrangement, the bracket member 29 is adapted to be readily adjusted about the axis of the stub shaft 35 substantially as indicated on comparison of the full line and dash line positions of the bracket block and as demonstrated by the directional arrows. in any adjusted position of the bracket 29, suitable corresponding adjustment of the finger assembly is adapted to be effected for optimum operating efficiency by relatively adjusting the shaft 17 in the bracket 29.

Where an unusually long row of the safety fingers 15 is necessaryand therefore the supporting shaft and stop bar must also be correspondingly long, another bracket 29 may be in supporting relation to the opposite end of the shaft, rather than utilizing the cantilever arrangement depicted which is adequate for relatively shorter rows of fingers.

In operation, after the safety finger assembly has been adjusted to an optimum relation to the table 8 having regard to the thickness of lumber to be processed, a single or paired piece'of lumber L is thrust forwardly against the finger curtain, with those fingers engaged thereby being swingably deflected, substantially as shown in FIG. 2. Beyond the fingers the leading end of the lumber is engaged by the first feed roller 1] and is then moved on forwardly through the machine. Should the saws strike a knot or for some other reason exert a sufficient backthrust on the lumber L to overcome the feed rollers 11, the chisel edges 20 of the fingers l engaging the lumber bite into the lumber and simultaneously exert a downwardly snubbing thrust against the lumber toward the table 8. Should the reverse or rearward ejection force on the lumber be sufficient to cause biting of the fingers down into the engaged lumber sufficiently to back the fingers to their rearward limit, the shoulders 22 of the fingers abut the stop bar 23 and further rearward swinging of the fingers is prevented so that the lumber piece is positively held against rearward escape. Since the lumber is still engaged by the feed rollers, they will normally resume feed of the lumber on through the saws unless whatever it is that caused rearward ejection movement of the lumber in the first instance will not permit further advance through the saws, in which case the operator of the machine will shut it down and withdraw the lumber. For highest efficiency,,the operating attitude of the safety fingers should be at as an acute an angle as practicable to the top surface of lumber fed thereby, with nevertheless ample leverage to assure thorough snubbing action in the event ofa backthrust. By having the chisel edges normally spaced above the table 8 and thus free from engagement therewith, the edges retain their sharpness and do not drop onto the table to cause any roughness or gouging under any circumstance.

lclaim:

l. A combination fiyback curtain and snubber of the character described, comprising:

a shaft;

a row of antikickback safety fingers having upper end portions pivotally engaged on said shaft with spacers between said upper end portions and the fingers extending downwardly from the shaft and normally biased with snubbing tips extending downwardly to engage freely upon a workpiece advanced in one direction thereunder but operative to stop movement of the workpiece in the opposite direction;

each of said fingers having on the rear portion of the upper end portion thereof an upwardly facing stop shoulder; and

a stop bar carried by said shaft over said upper end portions of the fingers and releasably engageable by said stop shoulders to stop rearward swinging in maximum snubbing position of the fingers.

2; A combination according to claim 1, including means releasably attaching said stop bar to said shaft.

3. A combination according to claim 1, including a bracket mounting one end portion of said shaft rotatably, and means for securing the shaft fixedly in rotatably adjusted position with respect to the bracket.

4. A combination according to claim 3, including means supporting said bracket and including means for adjusting the position of the bracket relative to said bracket supporting means.

5. A combination according to claim 1, including opposite end spacer blocks on and between said bar and said shaft, and means securing said bar and said spacer blocks to said shaft.

6. A combination according to claim 1, including a supporting bracket block having a bore within which one end portion of said shaft is received, said end portion having a shallow annular groove therein, and a set screw carried by said bracket block and engaging said shaft in said groove to secure the shaft in the bracket block.

7. A combination according to claim 6, said block being elongated and projecting forwardly beyond said shaft end portion and having a horizontal slot extending inwardly from the end remote from said shaft, the slotted end portion of the bracket block having a shaft bore intersecting said slot and adapted to receive a supporting shaft on a machine frame therethrough, and a securing bolt extending through the portions of the bracket block separated by said slot to clamp said portions onto the supporting shaft.

8. A combination according to claim 1, including means for carrying said shaft in cantilever fashion, and means for adjusting said carrying means for adjusting the vertical position of said shaft and thereby of said fingers.

9. A combination according to claim 1, including means for supporting said shaft, and means for securing said shaft in pivotally adjusted relation on said supporting means and thereby enable adjustment of said stop bar by said pivotal adjustments of the shaft.

10. A combination according to claim 9, including means supporting said shaft enabling vertical adjustments of the shaft and thereby of said bar and said fingers.

11. A combination flyback curtain and snubber of the character described, comprising:

a row of fingers having snubbing tips at one end;

each of said fingers being of a downwardly tapered shape having an upper head portion and said snubbing tips comprising substantially chisel edges directed generally downwardly and forwardly;

' said fingers having rear cam edges;

each of said fingers having on the upper head end portion a rearward upwardly facing shoulder;

means relatively swingably supporting the fingers comprising a shaft on which the head end portions of the fingers are swingably mounted;

spacer washers between the head end portions of the fingers;

a stop bar overlying said fingers and releasably engageable by said shoulders;

respective opposite end spacer blocks on and between said bar and said shaft;

bolts securing said bar and said spacer blocks to said shaft;

a supporting bracket block having a bore within which one end portion of the shaft is received;

said end portion having a shallow annular groove therein;

a setscrew carried by said bracket block and engaging said shaft in said groove to secure the shaft in the bracket block;

said block being elongated and projecting forwardly beyond said shaft end portion and having a horizontal slot extending inwardly from the end remote from said shaft;

the slotted end portion of the bracket block having a shaft bore intersecting said slot and adapted to receive a supporting shaft on a machine frame therethrough; and

a securing bolt extending through the portions of the bracket block separated by said slot to clamp such portions onto the supporting shaft.

Claims

1. A combination flyback curtain and snubber of the character described, comprising: a shaft; a row of antikickback safety fingers having upper end portions pivotally engaged on said shaft with spacers between said upper end portions and the fingers extending downwardly from the shaft and normally biased with snubbing tips extending downwardly to engage freely upon a workpiece advanced in one direction thereunder but operative to stop movement of the workpiece in the opposite direction; each of said fingers having on the rear portion of the upper end portion thereof an upwardly facing stop shoulder; and a stop bar carried by said shaft over said upper end portions of the fingers and releasably engageable by said stop shoulders to stop rearward swinging in maximum snubbing position of the fingers.

2. A combination according to claim 1, including means releasably attaching said stop bar to said shaft.

11. A combination flyback curtain and snubber of the character described, comprising: a row of fingers having snubbing tips at one end; each of said fingers being of a downwardly tapered shape having an upper head portion and said snubbing tips comprising substantially chisel edges directed generally downwardly and forwardly; said fingers having rear cam edges; each of said fingers having on the upper head end portion a rearward upwardly facing shoulder; means relatively swingably supporting the fingers comprising a shaft on which the head end portions of the fingers are swingably mounted; spacer washers between the head end portions oF the fingers; a stop bar overlying said fingers and releasably engageable by said shoulders; respective opposite end spacer blocks on and between said bar and said shaft; bolts securing said bar and said spacer blocks to said shaft; a supporting bracket block having a bore within which one end portion of the shaft is received; said end portion having a shallow annular groove therein; a setscrew carried by said bracket block and engaging said shaft in said groove to secure the shaft in the bracket block; said block being elongated and projecting forwardly beyond said shaft end portion and having a horizontal slot extending inwardly from the end remote from said shaft; the slotted end portion of the bracket block having a shaft bore intersecting said slot and adapted to receive a supporting shaft on a machine frame therethrough; and a securing bolt extending through the portions of the bracket block separated by said slot to clamp such portions onto the supporting shaft.