US2109040A - Box press - Google Patents

Description

P55. 22, T938. 11 TWOMIZEY BOX PRESS F'i'led Aug; 10, 1935 s Sheets-Sheet-l INVENTOR.

, ATTORNEYS Feb. 22, 1938. H. E. TWOMLQEY 30 7 BOX PRESS Filed Aug. 10 1935 5 Sheets-Sheet 5' ATTORNEY$ porting table.

Patented Feb. 22, 1938 UNITED STATES BOX PRESS Herbert E. Twomley, Riverside, Calif., assignor,

by mcsne assignments, to Food Machinery Corporation, a corporation of Delaware Application August 10, 1935, Serial No. 35,665

10 Claims.

My invention relates to presses, and has particular reference to box presses employed to come press contents within a box and to apply lids thereto. 0

In the packaging of fruits, vegetables, and similar commodities, it is the common practice to fill a box or crate with the desired contents, placing a suflicient quantity of the contents within the box to extend a considerable distance above the upper edges of the walls of the box and then to apply lids or covers to the boxes by pressing the covers down upon the extending overpacked contents, compressing the contents down into the box, and then securing the covers in place thereon. These machines usually comprise a box-supporting table upon which boxes filled with their contents may rest immediately below lid-pressing elements which are adapted to engage and press the lids upon the boxes, either when the box-supporting table is lifted toward the lid-pressing mechanism or when the lidpressing mechanism is lowered toward the sup- In certain types of these machines, and in handling certain types of commodities, it is more convenient to lift the boxsupporting table toward a relatively stationarily disposed lid-pressing mechanism to accomplish the lid-pressing operations. It is also desirable that when the lid is compressed down upon the box it should be permanently secured to the box as by means of nails or other devices which may be applied while the pressing operation continues.

In such instances where the box-supporting table is lifted toward the compressing or nailing elements, it is essential that the table and the lid-pressing mechanism be normally spaced a suflicient distance apart to permit ready ingress into the machineof the boxes with their protruding contents, so that the amount of movement provided for the table must be relatively great in order to permit a relatively great compression of the contents of the box. Moreover, it is also essential that when the table has been elevated to compress the contents and to press the lids down upon the boxes, suflicient resistance must be provided to' oppose the forces which may be employed to drive nails or other securing members through the covers and into the boxes.

To provide this relatively great amount of movement of the box-supporting table, and to provide the necessary resistance for the nailing or securing" operations, various forms of drive mechanisms have been employed, such as hydraulic pistons and cylinders, using relatively non-compressible fluids, positive mechanical lifting mechanisms, such as screw jacks, chain lifts, and similar mechanisms. However it is frequently desirable to employ an air cylinder and piston mechanism for this purpose, but air, be-- ing relatively compressible, requires the employment of an extremely large volume of air at relatively high pressure to produce the long distance of travel and the required resistance to the downward thrust of the nailing or lid-secur-' ing mechanism, rendering it necessary'to provide large tanks for the storage of air and compressors of relatively great capacity, which renders the machine employing this type of drive expensive.

It is an object of my invention to provide a system of transmission between. a driving element, such as a fluid operated piston, and a driven element, such as a cox-supporting table, wherein a portion of the movement of the driving element causes the driven element to be moved through a relatively great distance, and then the further movement of the driving element moves the driven element directly, and at the same rate as the driving element.

Another object of the invention is to provide a fluid lift of the character set forth in the preceding paragraph, wherein a fluid driven piston of relatively short strokeis employed and in which one or more levers are employed between the piston and the bcx-supporting table to produce a relatively long travel of the table from the short travel of the piston mechanism.

Another-object of the invention is to provide a relatively simple control mechanism which may be employed for a fluid lifting means of the character set forth.

Other objects and advantages will be apparent from a study of the following specifications, read in connection with the accompanying drawings, wherein Figure 1 is a side elevational view of a lidding machine constructed in accordance with my invention;

Figure 2 is a detail front elevational view of a box-supporting table and lifting mechanism embodying my invention;

Figure 3 is a sectional view, taken along line III-III of Fig. 2; Figure 4 is a sectional view, taken along line IV-IV of Fig. 2; and Figure 5 is a detail sectional view taken along line V--V of Fig. 2.

Referring to the drawings, I have illustrated my invention as embodied in a machine for pressing and nailing lids to overfllled boxes or crates in which the machine includes a pair of side frames l and 2 interconnected by suitable crossbracing 3 and 4. Each of the side frames is provided with a. vertically extending upright guide 5 between the upper ends of which is suspended lid-pressing mechanism indicated by the reference character 6, and nailing mechanism indicated by the reference character I.

As will be understood by those skilled in the art, the'lid-pressing mechanism consists essentially in a frame-like structure having a pair of forwardly extending bracket arms 8, one on each side of the machine, spaced from each other by a distance just slightly less than the distance between the ends of the boxes upon which the machine is to operate. The bracket arms 8 are each provided with a. plurality of nail chucks 9, the lower ends of which are adapted to engage the extreme ends of a cover- Hi to press the cover ends into contact with the ends of a box I I when the box and bracketarms 8 are moved toward each other. If desired, suitable end tuckers I2 may/be supported upon the bracket arms 3 to extend over the edges of the box to engage any overhanging contents and press the same inwardly of the box immediately prior to the pressing of the cover ends into contact with the box ends.

In order to perform the pressing operations, I I

provide an elevating platform constructed as a box-supporting table 13 consisting essentially in a rectangular frame embodying side rails i4 and 1 l5 interconnected near their ends by a pair of cross bars l6, while a cross bar I! interconnects the side rail members near their middle. A plurality of rollers [8 are mounted between the side rails l4 and I5 to formthe box-supporting table into a sectional roller type conveyor over which boxes may be readily drawn into the machine andmoved outwardly of the machine.

The box-supporting table illustrated herein is adapted to move up and down and is guided by means of a pair of guide posts I!) and 23 at opposite ends thereof, the guide posts being secured rigidly to and depending from the end cross bars l6 of the box-supporting table. The side frame I of the machine is provided with a pair of inwardly extending vertical bearing members 2| through which the guide post l9 operates, while the side frame 2 is similarly provided with a pair of verticalbearing members 22 to guide the post 20 in its vertical movement.

-Inorder to accomplish the lifting and lowering operations of the box-supporting table I3, I provide driving elements constituted herein as an air cylinder and piston mechanism compris= ing a relatively short cylinder 23 suitably supported upon the frame of the machine, as upon the cross-brace 3 thereof. The cylinder 23 may be formed of a section of cylindrical tubing having a lower head 24 and an upper head 25 c ped thereon by means of suitable tie-bolts 26. The upper head 25 is provided with an opening through which extends a piston rod 28 connecting with a piston 29'movable vertically within the cylinder 23. Thus by passing air under pressure into the cylinder beneath the piston 29, the piston and its rod 28 will be raised, while escape of the air from beneath the :piston will cause the piston to be lowered. Air may beintroduoed and exhausted from'the cylinder 23 in any suitable manner, though I prefer to provide the lower head 24 with an inlet port 3|! to which may be connected a suitable supply pipe 3| by which air is admitted beneath the piston, while an exhaust port 32, connected to an exhaust pipe 33, may

be provided to permit air topass out of the cylinder.

By referring particularly to Fig. 1, it will be observed that the height of the cylinder 23 is relatively small as compared to .the distance of travel (indicated by the legend travel) through which the box-supporting table l3 must be elelinks and levers which will multiply the amount of movement, during apart of the stroke of the piston and which will constitute a direct drive during the later portion of the piston stroke. Referring particularly to Figs. 3 and 4, it' will be observed that the upper end of the piston rod 28 is formed with a reduced section 34 to which is secured a cross head 35, each end of which is bifurcated, as indicated at 36, to receive a pair of levers 3i pivoted to the cross head 35 as by means of a pin 33, while the opposite end of the cross head 35 supports a similar pair of levers 33 pivoted thereto by means of a pin 40.

The levers 3? are interconnected at their inner ends by means of pins 4| and levers 39 are interconnected at their inner ends by means of pins 42, and upon each of the pins 4| and 42 there is mounted a roller 44 and 45, respectively. The roller 44 is aligned with and is engaged in a. notch 46 formed upon the edge of a vertically extending guide means or plate 41, which plate is rigidly secured to the uppermost head 25 of the cylinder 23 so that upon elevation of the piston '29 and its cross head 35 the levers 31 will be a pivotal connection with a link 49, the opposite end of which is pivoted as at50to a lug 5! formed upon and extending down below the centercross bar H of the box-supporting table structure. In like manner the roller 45 for the levers 39 is engaged in a slot 52 in a second vertically extending plate 53, which, like the plate 41 is rigidly mounted upon the upper head 25 ofv the cylinder 23. Likewise the outer. ends of the levers 39 are connected by means of a pin 54 to one end of a link 55'the opposite end of which is connected as at 56 to a downwardly depending lug 51 formed upon the. center cross bar i! of the box-supporting table structure. In order to brace the upper ends of the guide plates 41 and 53, I may interconnect them by means of a bar 58, the plates 41 and 53 being spaced apart to provide an elongated slot' 59 through which the central portion of the cross head 35 may move vertically.

It will be observed that the point of application of lifting force' to the levers 31, namely at the pin 38, is closer to the fulcrumed point of this lever than is the connection 48 between the levers 37 and the link 49. Thus a relatively short upward thrust on the cross head 35 will cause a relatively great lifting movement. of the boxsupporting table l3. v A

Referring particularly to Fig. 3, it will observed that I have illustrated therein the posi-. tion of the piston, le'vers '31-.-39, links 49 and 55 that the initial upward movement of the table operates through the greatest leverage ratios to swing the levers 31 and 39 through an arc slightly less than 180. As the piston 29 continues to rise in its cylinder, the upward force transmitted through the pins 38 and 48 will cause the toggle links formed by the levers 31 and links 49 and by levers 39 and links 55, respectively, to be substantially straightened out, which will cause the rollers M and 45 to be withdrawn from their notches 46 and 52, respectively. Continued upward movevment of the piston 29 will raise the pins 38 and 40 additionally, thus causing the now straightened toggle links to be lifted bodily upwardly, the

rollers 44 and 45 riding upon the exterior edges or" the plates 4'! and 53. Thus while a short initial travel of the piston 29 is employed to rapidly raise the table l3 through its levers and links, this action occurs at a time when the only resistance to the lifting of the table I3 is the weight of the box and its contents, while the'last portion of the travel of the table i3 is additionally resisted by the pressing of the cover down upon the box, and this is accomplished by a direct upward thrust of the piston 29 transmitted directly through the straightened toggle links, thus applying the full lifting power of the piston to accomplish this thrust.

By the employment of the structure just described, it will be apparent that a relatively small volume of air is required to accomplish the lifting of the table i3, while the application of the force of such small volume of air is distributed throughout the cycle of operations so that the maximum power is delivered at the time the maximum resistance is encountered This is of unusual advantage when, (as is usual) the amount of space which must be allotted to a tank or reservoir for compressed air is limited, each operation of the lifting of the table requiring but a relatively small volume of and thus the capacity of the tank or reservoir may be relatively small. 4

Referring particularly to Figures 1, 2 and 4, I have illustrated the controlling apparatus by which the lifting and lowering operations of the table l3 may be accomplished by an operator of the machine, this controlling apparatus including essentially a pair of valves, intake control valve 60 interposed in the pipe 35 between the source of supply or term and the cylinder 23 and an exhaust valve Si interposed in the pipe 33 between the cylinder 23 an exhaust outlet 62.

The ntake valve 6! may be readily controlled by means of a foot pedal 53, pivoted as at 64 upon an upstanding lug 65 formed upon the base 66 of the machine, extenfing immediately above the valve 68. The valve 88, being of the normal 7 closed type, will he opened only when the pedal 63 is actuated by the operator of the machine and at that time will admit air from the source of supply into the cylinder 23.

If, during the ascent of the box-supporting table 13 it appears that the contents of the box are likely to be crushed during the pressing operations, or that the cover is not properly aligned or adjusted relative to the box, the table I 3 may be stopped at any position by the mere release of the pedal 53. The table is held in the elevated position upon the release of the pedal 63 because the-exhaust valve 5| in the-exhaust line 33-is normally closed and will prevent the escape of air from the cylinder 23 until this valve 6| is opened.

If it is desired to lower the box-supporting table l3 prior to the completion of the nailing operation, the valve 6| may be opened bymeans of an auxiliary foot pedal 81 rigidly secured to a shaft 68 extending across the machine and journaled in suitable bearing brackets 69 and Ill at opposite sides of the machine. Rigidly secured upon the shaft 68 near either of its ends are levers H and 12, respectively, interconnected at their outer ends by means of a rod 13, which rod is secured to the operating element of the valve 8|. Thus upon depression of the pedal 61, the valve 6| will be opened and the air which has been admitted into the cylinder 23 under the piston will be exhausted, permitting the piston to be lowered and returning the box-supporting table to its lowermost position.

If, however, it appears that the condition of the contents of the box and cover are such that .the pressing and lidding operations may be completed, the operator continues to hold the pedal 63 depressed until the box has been elevated against the nail chucks or other lid-engaging elements to spring the cover ends down into contact with the box ends. Since the bracket arms 8 are rigidly secured to the frame of the machine, it will be apparent that the full force of the compressed air admitted to the cylinder 23 may be employed until forward movement of the table i3 is stopped by the positive resistance exerted bythe lid-pressing mechanism.

The cover is now in position to be nailed or otherwise secured upon the box and the nailing operations may now occur.

By referring particularly to Figure 1 it will be observed that the nailing mechanism for one end of the machine includes a forwardly extending bracket 55, one end of which is slidably mounted upon the bracket 8, as by means of a slide bearing l6, while the opposite end of the bracket 55 is connected as at W and id to a cross head structure 19 extending between the uprights 5 on opposite sides of the machine. It will be understood by those skilled in the art that at the opposite end of the machine a similar bracket 5 will extend forwardly of the machine being suitably slidably supported upon the bracket 8 at that end of the machine, the two brackets l5 and the frame 78 constituting a nailing frame mechanism which may be reciprocated vertically relative to the brackets 8 and the nail chucks 9 by means of a connecting rod 99, one end of which is coupled to the frame l9 and the other end of which is coupled to a crankpin 8! extending forwardly from a wheel 82 adapted to be rotated by means of a motor 93. In order to permit the operator of the machine to control the movement of the wheel 82 to cause the nailing mechanism to move downwardly toward the box and to return to its uppermost position'as illustrated in Fig. 1, the motor 83 is coupled to the wheel 82 through suitable reduction gearing 84 and a clutch 85 which clutch is adapted to be engaged by the depression of a nailing pedal 86 pivoted as at 81 upon the frame of the machine and connected by means of a link 88 to a clutch operating yoke As will be understoodby those skilled in'the art, the clutch pedal 86 may be provided with clutch 85 to be disengaged at the end of one rvolution of the wheel 82 so as to prevent a second nailing operation should the operator inadvertently maintain the pedal 86 depressed after the first nailing operation takes place. This being a common practice in the art, it is not believed essential to illustrate or describe the same herein.

Each of the brackets I5 of the nailing mechanism is provided with a plurality of downwardly depending nail punches 99 extending into and through the nail chucks 9 so that when the nailing mechanism and the arms are moved downwardly relative to the brackets 8 and nail chucks 9, the nail punches 99 will drive nails through on the wheel 82 so disposed relative to the crankpin 8| that at the termination of the nailing operation the cam 9| will engage a rod 92 and move the same forwardly.- The rod 92 may be provided with a tailpiece or other coupling means 93 to engage the rod 13 to press the same forwardly in the same manner as though the release pedal 61 had been actuated, thus opening the valve 60. By properly proportioning the length of the cam surface 9| the valve 6| will be held open a suflicient length of time to permit all of the air to be exhausted from the cylinder 23, it being preferable to form the exhaust pipe 33 of relatively large diameter so that the exhausting of the air may occur with great rapidity. y

In order, however, to prevent the too rapid descent of the table I3, I prefer to provide a I dash potor oil check mechanism governing the speed of descent of this table i3, which may comprise a cylinder 95 having a suitable piston 99, the piston rod 91 of which is provided with a yoke 98 hearing a crosspin .99. The box-supporting table I3 is provided with a U-shaped yoke I99 surrounding the pin 99 and preferably being of an elongated character to provide an elongated slot l9l by which the box-supporting table is permitted both lifting and lowering movements through a relatively short distance before positive connection is made between the dashpot 95. Thus the initial upward movement and the initial downward movement of the table l3 will be relatively free, while the latter portions of the movement of the box-supporting table will be restrained by the oil check dashpot mechanism.

The operation of the machine through a complete cycle is as follows:

Assume that the machine is in the position shown in Fig. 1 in which the table I3 is in lowermost position ready to receive a box and the pedals 53, 61 and 68 are in normal upper position. Under these conditions the valves controlling fluid flow into and out of the cylinder 23 are closed and the clutch is disengaged. Let it be assumed that the motor 83 is in operation. Assume also that a box II is in position on the table i 3 and that a box lid I9 is retained in the lid-pressing mechanism 6.

The operator then depresses the pedal 63 which opens the intake valve '69 and admits pressure fluid through the line 3| into the bottom of the cylinder 23, thereby raising the piston 29, the piston rod 28 and the cross head 36. The movement of the cross head 36 and the pins 38 and 49 attached thereto first rotates the levers 31 and 39 "about the rollers 44 and 45, respectively as fulcrums until the rollers 44 and 45 are carried out of the slots 46 and 52 in the frame members 41 and 53 after which the levers 31 and 39 are moved directly upwardly, all as'previous 1y described, to first lift the table l3 and the box ii thereon very rapidly into close proximity to the lid-pressing mechanism 6 and then move it slowly but with great force through the final distance to press the boxinto firm engagement with the lid.

Should it appear during the upward movement of the table i3 that the contents of the box might be crushed or that the cover is not properiy aligned, or that anything else is wrong, the operator can immediately stop the upward movement by releasing the pedal 63 to cut off the fluid supply to the cylinder 23. If the operator should find it necessary to lower the table he can do so by stepping on the pedal 61 thereby opening exhaust valve 6| and releasing fluid from the cylinder 23 to permit downward movement of the piston 29 and the table. 6

However, if everything appears to be in order the operator maintains pedal 93 depressed until the box 8 l is carried up into firm engagement with the lid l9 after which the operator actuates the nailing mechanism by depressing the'pedal 96.

.As previously indicated, it is customary to pro-' vide a suitable cam-actuated mechanism for causing the clutch 85 to be automatically disenaged at the end of one revolution of the wheel 92 so as to prevent a second nailing operation should the operator inadvertently maintain the pedal,86 after the first nailing operation takes place. Such a mechanism may be provided in the present machine, but has not been specifically illustrated because such mechanisms are well-known in the art and specifically do not constitute a part of the present invention. It may therefore be'assumed that either. by reason of an automatic release mechanism of the type referred to or by the release of pedal 86 at the proper time by the operator, the wheel 83 is stopped at the conclusion of one revolution.

During the final movement of the wheel 82 incompleting its revolution, the cam 9| thereon actuates the push rod 92 which, acting through the coupling means 93, presses the rod 13 forwardly. in the same manner as though the release pedal 6! had been actuated, thereby automatically opening the exhaust valve 6! to permit exhaust of the air from the cylinder 23 so that the table l3 and the lidded box thereon are automatically lowered into the position shown inFig. 1. During this operation excessively rapid downward movement of the table is prevented by the damping action of the dash pot mechanism comprising the cylinder as having the piston 96 connected through piston rod 91, yoke 98 and cross pin 99 to the table. By virtue of the fact that the pin 99 has substantial free movement in the slot in! in the yoke I99, the table drops rapidly at first without restraint from the piston 96 until the pin 99 reaches the lower end of the slot l9i, but after that the piston is forced to move and the frictional resistance to movement of the piston offered by the fluid in the cylinder 95 controls and limits the rate of movement of the table.

While I have illustrated the pressing apparatus as a box-supporting table and a fluid cylinder and piston mechanism, it will be understood by those skilled in the art that the transmission system for causing rectilinear movement of the table [3 by a shorter rectilinear movement of the pistonv 29 is well adapted to the transmission of rectilinear movement from any driving member hav-v in rectilinear movement to any driven-member having linear movement requiring a greater rate of travel per unit of distance of movement. of the driving member for a portion of the drive and restruetion shown herein, except as defined in the appended claims.

I claim:

1. In a power transmission, a driving'member movable through a predetermined distance, a driven member, a lever, means connecting one end of said lever. to said driven member, means connecting an intermediate point of said lever to said driving member, guide means eng the opposite end of said lever to form a fulcrum about which said lever is rotated during a portion of the movement of said driving member and form? ing a slide bearing along which said lever slides during the remaining portion of the movement of said driving member. L

2. In a power transmission, a driving member movable through a predetermined distance, a driven member, a lever, means connecting one end of said lever to said driven member, means connecting an intermediate point of said lever to said driving member, guide means engaging the opposite end of'said lever and having a guide surface thereon including a portion forming a slide bearing along which said lever may move member directly to said driven member and hav-- ing a recess receiving said end of said lever to form a fulcrum about which said lever rotates during another portion of the movement of said driving member to cause said driven member to move at a greater rate than said driving member during said other portion of the movement of said driving member.

3. In a power transmission, a driving member movable in a straight path through a predetermined distance, a driven member movable rectilinearly, a lever, means connectingone end of said lever to said driven member, means connecting an intermediate point of said lever to said driving member, guide means forming a bearing surface for the opposite end of said lever, in-

cluding a recess for receiving said end of said lever to form a fulcrum about which said lever rotates during a portion of the movement of said driving member to move said driven member at a greater rate than said driving member, and a slidsurface communicating with said recessto form a track along which said lever may move during the remaining portion of the movement of said driving member to cause said driving member and said driven member to move at the same rate, transmitting power direct from said driving member to said driven member.

4. In a power transmission, a driving member movable "in a straight path through a predetermined distance, a driven member movable rectilinearly, a lever, means connecting one end of; said lever to said driven member, means connecting an intermediate point of said lever to said driving member, guide means forming a bearing surface for the opposite end of said lever including a recess for receiving the end of said lever to form a fulcrum about which said lever rotates during the first portion of movement of ing member to thereby transmit driving force from saiddriving, member to said driven member directly, causing said driving member and said driven member to move at the same rate.

5. In a power lift, a base, a cylinder secured to said base, a piston reoiprocable in said cylinder, a platform, a lever, means connecting one 'end'of said lever to said platform, means conmeeting. an intermediate point of said lever to said piston, guide means stationarily mounted relative-to said cylinder for engaging the opposite end of said lever, forming a fulcrum about which said lever rotates during a portion of the movement of said piston, and forming a slide bearing along which said lever slides din-ing the remaining portions of the movement of said piston.

6. In a box pressing machine, a box-supporting table, box lid pressing means mounted above said table, -mea,ns operable at will for elevating and lowering said table including a driving-member reeiprocable in a vertical direction, a lever, means connecting one end of said lever to said table, means connecting the intermediate point of said lever to said driving member, a cam engaging the opposite end of said lever forming a fulcrum about which said lever rotates during a portion of the movement of said driving member and forming a slide bearing along which said lever slides during the remaining portion of the movement of said driving means.

7. In a box pressing machine, a box-supporting table, box lid pressing means mounted above said table, means operable at will for elevating and lowering said table including a driving member reciprocable in a vertical direction, a lever, means connecting one end of said lever to said table, means connecting the intermediate point of said lever to said driving member, a cam engaging the opposite end of said lever having a guide surface along which said lever may slide during portions of the movement of said driving member and having a notch extending from said guide surface to engage said lever to form. a fulcrum about which said lever may rotate when moved by said driving member during another portion of the movement of said driving member, whereby a relatively small amount of movement of said driving member will cause a relatively great amount of movement of said box-supporting table as said lever is rotated and whereby said drivingmemher will directly move said box-supporting table when said lever slides along said cam.

porting table upwardly toward said pressing and lid-securing means, comprising vertically reciprocable means, lever means interconnecting said reciprocable means and said table. operable during the first portion of the upward movement of said moving means to move said table through a lever action and operable during the final upward movement of said moving means to transmit a direct upward thrust from said reciprocable means to said table.

9. In a machine for applying covers toboxes, a box-supporting table for supporting boxes to be lidded, means on said machine above said table for pressing covers upon boxes, means on said machine for securing covers to boxes, means operable at will to move said box-supporting table upwardly toward said pressing and lidsecurlng means, cylinder and piston means for lifting and lowering said table, lever means interconnecting said piston and cylinder means with said table to cause said table to be lifted through a relatively great distance upon initial movement of said piston and cylinder means through a relatively'small distance, and subse-Y quently transmitting the thrust of said piston table for pressing covers upon boxes, means on 11 said machine for securing covers to boxes, means operable at will to move said box-supporting table upwardly toward said pressing and lid-securing means, cylinder and piston means for lifting and lowering said table, lever means in 14 terconnecting said piston and cylinder means with said table to cause said table to be lifted through a relatively great distance upon the initial movement of said piston and cylinder means through a relatively small distance, and for 2 transmitting the thrust of said piston and cylinder means as a direct thrust during the final portions of the movement of said piston means,

whereby a relatively short stroke produces agreat travel of said table. 21

\ HERBERT E.- TWOLELEY.

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