US2003843A

US2003843A - Power press

Info

Publication number: US2003843A
Application number: US591540A
Authority: US
Inventors: Jr Robert Temple
Original assignee: ROBERT TEMPLE Inc
Current assignee: ROBERT TEMPLE Inc
Priority date: 1932-02-08
Filing date: 1932-02-08
Publication date: 1935-06-04
Anticipated expiration: 1952-06-04

Description

June 4, 1935. R. TEMPLE, JR 2,003,843

POWER PRESS 'Filed Feb. 8, 1952 2 sheets-sheet 1 INVENTOR.

ATTORNEY 5 R. TEMPLE, JR

June 4, 1935.

POWER PRES S Filedv Feb. 8, 1932 2 Shee'cs-SheerI 2 f, j j

Patented June 4, 1935 2,003,843 POWER PRESS Robert Temple, Jr., Denver, Colo., assignor to Robert Temple, Inc., Denver, Colo., a corporation of Colorado Application February `8, 1932, Serial No. 591,540

31 Claims.

This invention relates to power presses and its primary object is to provide'a press employing as its motive agent, an explosive conned in a restricted chamber, to bring by its expansive force,

a movable pressure element or hammer, into sudden and violent contact with the work. The present press as illustrated in the drawings and hereinafter to be described is especially adapted for forming joints between originally separated parts, and more particularly for. the formation of bonding joints of electric transmission bars and wires or of other equipment requiring the bonding' of sections of metallic conductors for the transmission of electric current. By the use of a press constructed in accordance with the present invention, an intimate bond is producedbetween metallic electric conductors and their ouplings, which provides the mechanical strength necessary to sustain stresses to which the conductors are subjected and which insures ..the intimate electric contact between the coupling and the sections of the conductor necessary for the uninterrupted flow of current between them. It is to be understood, however, that while the press as shown is particularly designed for the above stated purpose, it may be effectivelyemployed for other work in which a powerful and sudden movement of an impact elementvis an essential requirement.

A press of similar character haszbeen shown and described in my application for patent Serial No. 557,857 led August 18, 1931, and the present invention is directed to certain changes land improvements which increase the practicabilityand eiiciency of the device.

As stated hereinbefore, the press is particularly:

adapted for joining conductors of electricity in a coupling-member, and the product of it's operation in vthis respect has been shown and described in my co-pending application for patent Serial No. 562,754, iiled September 14, 1931.'l

In the present application, the press has been designed to connect two conductors of electricity in end-to-end relation within a coupling-sleeve, by delivering a sudden and powerful blow upon the sleeve at opposite sides of a mediate point, thereby off-setting the sleeve and the wires within the Same and at the same time widening the parts by lateral distortion. As a result of these actions, the wires are securely locked in the sleeve in in timate electrical contact with the same. Inasmuch as the the product of the press has been fully described in the before-mentioned application for patent,.the present invention. will be unhas a groove I3 to receive the coupling sleeve I4 derstood, without further detailed description of the same.

In the accompanying drawings in the several views of which like parts are similarly designated,

Figure 1 represents a vertical sectional eleva- 5 tion of the improved press,

Figure 2, a similar elevation in the plane indicated by the line 2--2 in Figure 1,

Figure 3, a .transverse section along the line 10 line 8-8 of Figure 6. v

Referring first to Figures l to 4 of the drawings, the press comprises a body or main frame 5 having in its lower -portion a seat for a die or anvil l. The press is at this point of bifurcated form and the anvil is placed upon its seat by sliding it between the leg-portions 8 of the press.

The anvil is subsequently clamped in place by means of tapering wedge-pins 9 driven into complementary grooves IU of the leg portions and of a flanged base I2 embracing the ends of the same. The pins 9 and the base I2 thus provide a clamping element for securing the anvil in place between the legs of the frame. The anvil of conductors of electricity I5 or other work, and

the groove is formed in cross-section to correspend with the exterior shape of the work.

Th rame or body 5 has above and as a continuatiofir-olthe space -between its parallel legmembers, a`cylipdrical bore I6 partially lined with a bushing I1"`f`acid resisting steel or other suitable metal. This bushing is mechanically fitted and pressed into the bore and it is anged at its upper end to engage with a shoulder I8 of the bore. The provision of an acidproof bushing is an important factor since it prevents corrosion by products of the explosive gases.

Above the shoulder I8, the bore is screw-threaded to receive and secure the lower portion of a d cylinder-head I9. The head hasan axial bore 20 which in the operation of the press functions as an explosion chamber, the lower end of which is widened by a counterbore 2| to spread the expansive gases produced by an explosion in the when the chamber 23 over the impact-surface of a piston 22 slidably iitted in the bushing of the cylinder.

This piston carries at its lower end an upper die or hammer 23 by means of screw-threads 24, and it has an axial bore 25, in which fits a springpressed pin 26 which in theoperation of the press engages the work on the anvil at a medial point tohold it against displacement. The hammer engages the work at opposite sides of this point as clearly shown in Figure 2, and its workstriking faces 21 slant outwardly as best shown in Figure 2, to produce tapering indentations on the outside of the sleeve I4 and on the conductors I5, so that deeper shoulders and a wider spread is produced adjacent the central portion of the sleeve and at the ends of the conductors.

This is a distinct improvement over the joints disclosed in the before mentioned earlier applications for patent, since it strengthens the lock between the sleeve and the conductors and betters the intimate conductive contact of the conductors with the sleeve.

The pin 26, slidably fitted in the bore of the piston 22, is partially hollow t'o house a helical spring 28 which abuts against the breast o the bore of the piston, to hold the pin in contact with the Work, and a stud 29 screwed into the piston projects into the spring to hold it against lateral deformation.

A packing-ring 30 between the bushing of .the cylinder andthe end of the cylinder head I9 provides for a gas-tight joint between the same.

The bore of the cylinder head is c'ountersunk at its upper end as at 3I, to support a cartridge 32 which in practice, occupies the upper portion of the explosion-chamber 20. This cartridge which constitutes the motive agent of the press,

` contains an explosive powder and above the same a detonating cap 33.

The cartridge is accurately fitted in the upper portion of the explosion chamber, leaving the lower portion of gases produced by the ignition of the explosive charge. The upper portion of the cylinder head, above the main frame of the press, is reduced in diameter and screw-threaded for a cap 34 which closes the explosion chamber and which has a hollow extension 35 closed at its upper end by a screw plug 36. The cap provides a carrier and a housing for the firingmechanism of the press.

which consists of a piston 31 slidably tted in the interior bore of the extension 35, a stem 38 formed integrally with the piston 31, projecting through a central opening of the screw plug, and a pin 39 at the lower side of the piston which in the operation moves through an aperture of corresponding size in the portion of the cap 34 at which it engages the piston-head I9, to forcibly engage with the detonating cap-of the cartridge.

The forcible engagement of the ring pin 39 with the detonating cap 33 is effected by expansion of a helical .spring 43 in the space between the piston 31 and the plug 36, which is compressed piston is moved outwardly to the position illustrated in Figure 4.

'I'he piston stem 38 has at its upper end, a head 40 to facilitate its upward movement, and it is furthermore provided with a transverse aperture4l to receivea cotter pin 42 whichI by engagement with the plug 36, holdsvthe firing-element of the press in an inoperative position as illustrated in Figure 4 of the drawings.

In the operation of the press, the coupling sleeve I4 of the conductors is placed between the legs vof the frame after the anvil 1 has been rethereof vacant for the expansionmoved therefrom. The anvil is then replaced upon its seat and clamped in place by means of the wedge-pins 9 which are driven into the complementary grooves of the legs 8 and the flanges of the base I2. The pin 26 under pressure of its spring 28 holds the work in place upon the anvil. The spring also holds the piston 22 up against the cylinder head I9 to insure its contact with the lower end of the piston head and thereby dene the extent of the explosion-chamber 20.

' After the piston 31 of the iii-ing mechanism has been raised against the pressure of its spring 43 and held against retrograde motion by the cotter pin 42 in the aperture of its stern, as'illustrated in Figure 4, the cap 34 is unscrewed from the piston head and the cartridge 32 is inserted into theupper end of the explosion chainber 20. The cap is then replaced and the press is ready for operation.

The operator now withdraws the pin 42 from the aperture of the stem 38 with the result that the spring 43 by its consequent expansion drives the pin 39 at the end of the piston 31 forcibly into contact with the detonating cap 33 of the cartridge 32. This action explodes and res the powder-charge of the cartridge and the large volume of gases resulting from the explosion, by its expansive force, moves the piston 22 and the hammer 23 at the end thereof, downwardly with high velocity and brings the hammer into violent andsudden contact with the coupling sleeve on the anvil 1.

The sleeve I4 and the conductors I 5 within the same are in consequence deformed and compressed at opposite sides of its mediate point engaged by the nger 26 with the result that the conductors are firmly fixed inside the sleeve and in intimate conductive contact with the same as hereinbefore explained.'

The helical spring 28 acting upon the pin 26, holds the piston 22 and the hammer die 23 against operative motion until the desired or maximum amount of pressure is obtained from the explosive charge.

In the modified construction show'n in Figures 5 to 8 of the drawings, the firing mechanism is at a side of the explosion chamber, and the hammer-carrying piston is held in its elevated position by frictional means.

The press of the modied construction is particularly designed for compressing and bonding large size metallic bars, stranded cables and wires. A v

' The anvil 44 of the modified press is held in place on its seat by tenons 45 on its under side slidably iitted in grooves 46 in the seat. This prevents the legs of the press-frame or body 5 from spreading apart. A hammer 41 is as before screw-fastened at the lower end of a piston 48 tted for reciprocation in the bushed cylinder 49 of the press frame.

The piston 48 has'at its upper end a taper bore 50 to receive in frictional contact with its wall a correspondingly formed plug 5| at the lower end of a piston 52 slidably tted in the upper portion ofthe'piston cylinder 49. The space 53 of the cylinder between the

pistons

48 and 52 constitutes the explosion chamber of the press. The cartridge 54 is housed in a hollow gland 55 screwed into an opening ata side of the pressframe, which by means of registering apertures 56 of smaller diameter in the cylinder wall and the acidproof bushing 51 communicates with the explosion chamber 53.- The firing mechanism is The finger holding the work in place on the anvil has been omitted.

carried by a collar 58 rotatably fitted upon the cylindrical portion 59 of the press-frame.

The collar is slotted as at 60, to afford access to the bore in the gland 55 in which the cartridge 54 is tted so that the cartridge may be placed within the gland after the bore of the gland is exposed through the slot by rotary movement of the collar.

The collar 58 has a laterally projecting hollow boss 6i interiorly screw-,threaded to receive a corresponding threadedv holder 62 which carries the firing mechanism. This mechanism, as in the first described form of the invention, consists of a piston 63 slidably fitted in an axial bore of the holder, a screw plug 64 which closes the bore at its outer end, a stem 65 on the piston 63 extending through a central opening of the plug 64, a pin 66.0n the piston movable through a small aperture at the end of the holder 62 to engage with the detonating cap of a cartridge inserted in the gland 55, and a compression spring 61 in the holder for forcing the firing pin into contact with the detonating cap. The piston stem 65 has, as before, a head 68 exteriorly of e plug 64, and an aperture 69 for the applicavtion of a cotter pin to hold the firing mechanism in an inoperative position, as shown in Figure 4.

Handles 10 at the o uter end of the holder facilitate manual movement of the holder and the 3o collar on which it is mounted. It will be apparent that after a cartridge has been inserted into the gland 55 through the slot 60 of the collar and the latter has been returned to its original position, the ring pin 66 is in alinement with :55 the detonating cap of the cartridge to engage the same by expansion of the spring 61 after the piston has been released by withdrawal of the Cotter-pin from the aperture of its stem.

A piston head 15 screwed as before into an .4U interiorly threaded extension of the bore of the cylinder 49 of the press, has an axial bore in' which a stem 1| of the before mentioned piston 52 is slidably fitted. The stem 1I has a longitudinal groove 12, and a set screw 13 on the head 5 projects into the groove, to hold the stem against rotation. Upon a threaded extension 14 of the stem above the piston-head, ismounted a nut 16 with oppositely projectinghandles 11. The

nut has attened sides 18 topermit of its mov-l ing downwardly into opposite slots 19 in the upper portion of the head, when it is turned into register therewith by means of the handles 11.

'I'he piston 52 is beveled at itsupper face to engage in a correspondingly beveled countersink 80 at the lower end of the head 15, and a copper Washer 48a between the head 15 and the adjacent end of the bushing 51, seals the joint between these parts. f

In the operation of a press of the modified to construction, the work is, as in the press of the rst described form, inserted between the legs of the frame through the opening at the lower end thereof. The anvil 44 is then placed between the legs and upon its seat in which position the G5 tenons 45 in the corresponding grooves 46 prevent the legs from spreading apart. The nut 16 normally resting upon the head 15, is now turned so that its at sides are in register with the slots 18, thereby permitting of downward move- 70 ment of the piston 4B for the purpose of bringing vthe hammer 41 into contact with the coupling sleeve 8| on the anvil to press it rmly into the groove thereof. By the same movement, the taper-'plug 5| is forced rmly into the taper 5 bore or socket 50 of the piston 48.

The power-piston 48 is again raised by means of the handles 11 until the beveled face of the piston 52 engaging the bevel at the end of the head 15, and the parts are maintained in this position by turning the nut 16 at right angles out of register with the grooves 19 of the head.

The explosive cartridge is placed in the gland 55 through the slot of collar 58, after which the collar is turned by means of the handles 10 until the firing pin 66 is in alinement with the detonating cap at the end of the cartridge.

By means of the same handles the'holder 62 may be screwed into contact with the gland 55 to provide a gas-tight joint. By drawing the piston 63 outwardly by means of the head 68 of its stern, the spring 61 is compressed to provide the impetus necessary to bring the firing pin Vinto forcible contact with the detonating cap when the head is subsequently released. The consequent ignition of the explosive charge of the cartridge generates intense pressure in the explosion chamber 53 with the result that the piston 48 is released from the taper plug 5|, and driven downwardly to deliver a sudden and violent blow upon the coupling sleeve 8| on the anvil. As a result of this action the sleeve and the conductors of electricity 82 are deformed and expanded as before, to permanently anchor the conductors within the sleeve in intimate conductive contact with the same.

It will be apparent that the taper plug 5| of the piston 52 firmly pressed into the corresponding socket'56 of the power-piston 48 holds the latter against operative motion until the explosive in the cartridge is completely burned and the maximum pressure is generated in the explosion chamber 53.`

The connection between the stem 1| and the piston 48, by means of the taper plug 51 and the socket 56, also serves the purpose of returning the hammer-piston back into its proper place with relation to the explosion chamber, after firing, thereby maintaining a uniform combustion chamber at all times.

What I claim and desire to secure by Letters Patent is:

1. In a press of the character described, a frame having a cylinder, an anvil on the frame, a hammer piston in the cylinder to act upon work on the anvil, and a pressure member on the piston, adapted to subject the said work to pressure during action of the hammer to prevent the displacement of the work by said action.

2. In a press of the character described, a

frame having a cylinder, an anvil on the frame,

a hammer piston in the cylinder lto -act upon work on the anvil, and a spring-pressed-member on Vthe piston, adapted to subject the said Work to pressure d uring action of the hammer' to prevent the displacement of the Work by said action.

3. In a press of the character described, a frame having a cylinder, an anvil on the frame, a socketed hammer -piston in the cylinder to engage with work on the anvil, a linger movable in the socket of the piston, to engage with work acted on'by the hammer to'hold the same in place on the anvil, and acompresson spring in the socket, acting on the nger.

4. In a press of the character described, a frame having a cylinder, an anvil on the frame, a socketed hammer piston in the cylinder, to engage with work on the anvil, a nger movable in the socket of the piston, to engage with work on the anvil to hold the same in place, a helical spring in the socket, acting 4on thev linger, and a guide member on the piston tovprevent lateral deformation of the spring.

5. In apress of the character described, a

frame having a cylinder, an anvil on the frame,

and a hammer-piston in the cylinder having a contact-face slanting relative to a plane at right angles to the line of action of the hammer, to produce a correspondingly slanting indentation in a -surface of the work engaged by the hammer.

6.In a'press of the character described, a frame having a cylinder, an anvil on the frame, and a hammer-piston in the cylinder having con.- tact-faces slanting in opposite directions from the line of action of the hammer, to. produce correspondingly slanting indentations in surfaces of the work engaged by the hammer.

7. In a press of the character described, a-

framehaving a cylinder, an anvil on the frame, a piston in the cylinder, a pressure-member on the piston, adapted to engage with work on the anvil to hold the same in place, and a hammer at an end of the piston having contact faces to engage with the work at opposite sides of the pressure-member.

8. In a press of the character described, a frame having a cylinder, an anvil on the frame, a piston in the cylinder, a pressure-member on the piston, adapted to engage with work on the anvil to hold the same in place, anda hammer at an end of the piston having contact faces slanting oppositely from the pressure-member.

9. In a press of the character described, a frame having a cylinder, a shouldered bushing in the cylinder, a screw-head on the cylinder, engaging with the bushing, and providing an explosion-chamber in connection with the cylinder, firing mechanism for ignition of'an explosive charge in the explosion chamber, an anvil on the frame, and a hammer-piston in the cylinder, to engage with work on the anvil.

10. In a press of the character described, a frame having a cylinder, and spaced legs at an end thereof, an anvil seated in the space between the legs, a flanged clamping-element embracing the ends of the legs, and wedge-members between the clamping-element and the legs to secure the anvil in place.

1l. In a press of the character described, a frame having a cylinder, and spaced legs at an end thereof, an anvil seated in the space between the legs, a flanged clamping-element embracing the ends of the legs, the element and the legs having complementary tapering grooves, and wedge-members in, said grooves to secure the anvil in place.

12. In a press of the character described, a frame having a cylinder, an anvil on the frame, a head for the cylinder, a hammer-piston-in the cylinder, to engage with work on the anvil, and spring-meansl to effect a contact between the piston and the head.

13. In a press of 'the character described, a. frame having a cylinder, an anvil on the frame, a head for the cylinder, a hammer-piston in the cylinder, to engage with work on the anvil, a movable member on the piston, adapted to engage with the work to hold the same in place, and a compression spring acting upon the member and the piston, to force them in engagement with workon the anvil and with the head, respectively.

14. In a press of the character described, a frame having a cylinder, an anvil on the frame, a head-for the cylinder, a hammer-piston in the cylinder. to engage with work on the anvil, and

spring means adapted to eiect a contact between the piston and the head by reaction upon work on the anvil.

15'. In a press of the character described, a frame having a cylinder, an anvil on the frame, a head for the cylinder, a hammer-piston in the cylinder, to engage with work on the anvil, and a spring to yieldingly oppose the power-stroke of the piston.

16. In a press of the character described, a frame having a cylinder, an anvil on the frame, a head for the cylinder, a hammer-piston in the cylinder, to engage with work on the anvil, and

la spring to yieldingly oppose the power-stroke of the piston by reaction upon work on the anvil.

17. In a press of the character described, a frame having a cylinder, an anvil on the frame, a hammer-piston in the cylinder, to engage with work on the anvil, means to provide an explosionchamber in connection with thecylinder and to hold an explosive charge in communication with the explosion-chamber, ring-mechanism for ignition of a charge in the explosion chamber, and means to manually move the hammer-piston in the cylinder.'

18. y*In a press of the character described, a

frame having a cylinder, an anvil on the frame,

a hammer-piston in the cylinder, to engage with work on the anvil, means to provide an explosionchamber in connection with the cylinder and to hold an explosive charge in communication with the explosion-chamber, firing-mechanism for ignition of a charge in the explosion-chamber, and manual means frictionally connecting with the hammer-piston for moving the same in the cylinder.

19. In a pressof the character described, a frame having a cylinder, an anvil on the frame, a socketed hammer-piston in the cylinder to engage with work on the anvil, there being an expansion-space at an end of the hammer-piston, and a chamber to hold an explosive charge in communication with the expansion-space, ringi mechanism for ignition of a charge in the chamber, and an element having a taper-plug in the socket of the hammer piston, and movable to manually move the piston in the cylinder.

20. In a press ,of` the character described, a frame having a cylinder, an anvil on the frame, a

hammer-piston in the cylinder to engage with work on the anvil, there being an expansionspace at an end of the hammer-piston, and a chamber to hold an explosive charge in communication with the Aexpansion-space, ring mechanism for ignition of a charge in the chamber, a head for the cylinder, an element movable on the head, in frictional connection with the hammer-piston, and means for holding the element against sliding movement on the head, in one direction, whereby to permit of independent movement of the piston by the expansive force.

2 1. In a press of the character described, a frame having a cylinder, an anvil on the frame, a hammer-piston in the cylinderto engage with /work' on the anvil, there being an expansion-space at an end of the hammer-piston, and a chamber to hold an explosive charge in communication w1th the expansion-space, firing-mechanism for ignition of a charge in the chamber, a bored and s in one position and to move inwardly through a slot of the head in another position.

22. In a press of the character described, a frame having a cylinder, an anvil on the frame, a socketed hammer-piston in the cylinder to engage with work on the anvil, a bored head for theA cylinder, a piston in the cylinder normally seated against an end of the head, inspaced relation to the hammer-piston to provide an expansion- SpaCe, a chamber to hold an explosive charge, in communication with the expansion-space, firing mechanism for ignition of a charge in the cham.. ber, a taper-plug on the piston, frictionally engaging in a socket of the hammer-piston, and a stem for the piston, slidable in the head.

23. In a press of the character described, a frame having a cylinder, an anvil on the frame, a socketed hammer-piston in the cylinder to engage with work on the anvil, a bored head for the cylinder, a piston normally seated against an end of the head and frictionally engaging the hammer-piston in spaced relation thereto, the space betweenl the pistons constituting an expansioncharnber, a stem on the piston, slidable in the head, means to hold an explosive charge in communication with the explosion-chamber and firing mechanism for ignition of the charge,

24. ,In a press of the character described, a frame having a cylinder, an anvil on the'frame, a socketed hammer-piston in the cylinder to engage with Work on the anvil, a bored head for the cylinder, a piston lin the cylinder normally seated against an end of the head and having a frictional connection with the hammer-piston, in spaced relation to the same whereby to ,provide an expansion-space, a chamber to hold an explosive charge, in communication with the expansion-space, firing mechanism to ignite a charge in the chamber, and a stem on the piston, slidable in the bore of the head.

25. In a press of thel character described, a frame having a cylinder, an` anvil on the frame, a hammer-piston in the cylinder, to engage with work on the anvil, there being an expansion space at an end of the piston, a gland on the frame providing a. chamber for an explosive charge, in communication with the expansion space, a collar having a screw-threaded opening axially alined with the chamber, a screw plug in said opening, in gas-tight contact with the gland, and firing mechanism on the screw-plug, in operative relation to a charge in the chamber.

26. In a press of the character described, a frame having a cylinder, an anvil on the frame, a hammer-piston in the cylinder, to engage with Work on the anvil, there being an expansion space at an end of the piston, a gland on the frame providing a chamber for an explosive charge, `in communication with -the expansion space, a rotary collar on the frame having a screw-threaded opening normally alined with the chamber and having a slot to expose the chamber in an adjusted position, a screw-plug in the opening of the collar, abutting against the gland in the normal position of the collar, and

ring mechanism on the plug, in operative rela tion to a charge in the chamber when the collar is in its normalY position.

27. In a press of the character described, a frame having a cylinder, an anvil on the frame, a socketed hammer-piston in the cylinder to engage with work on the anvil, there being an expansion-space at an end of the hammer-piston, and a chamber to hold an explosive charge i in communication with the expansion-space,

firing mechanism for ignition of a charge in the chamber, a bored head for the cylinder having at the end of its bore, a countersunk seat, a second piston in the cylinder denning the expansion-space and having a beveled end normally engaging the countersunk seat, a taper-plug at a side of the second piston, to frictionally engage in the socket of the hammer-piston, and a stem for the piston movable in the bore of the head.

28. In a press of the character described, a frame having a cylinder, an anvil on the frame,

a hammer-piston in the cylinder, to engage with work 0n the anvil, there being an expansion space at an end of the hammer-piston, and a cham= ber to hold an explosive charge in communication with the expansion-space, ringeinechanism forn ignition of a chargein the chamber, and an element connected with the hammerpiston to manually move the same to engage with work on the anvil, andto automatically release the same by movement of the hammer-piston bythe expansive force.

29. In a press of the character described, a frame having a cylinder, an anvil on the frame, a hammer-piston in the cylinder to engage 'with work on the anvil, an element providing an expansion-space at an end of the hammer-pis ton, and having a frictional connection with the hammer-piston to manually move the same to engage with work on the anvil, there being a chamber for an explosive charge in communication with the expansion-space, and tiring mechanism for ignition of a charge in the charnber.

30. In a press of the character described, e. cylinder, an anvil, a hammer-piston in the cylinder to engage with work on the anvil, means providing an explosion-chamber in connection with the` cylinder, and friction-means associated with the piston yieldingly opposingr movement of the hammer during expansion of the ignited gases in the explosion chamber.

31. In a press of the character described, a cylinder, an anvil, a hammer-piston in the cyl inder to engage with work on the anvil, means providing an explosion-chamber in connection with the cylinder, and friction-means associated vwith the piston comprising a tapered bore and a tapered plug insertable therein, yieldingly opposing movement of the piston during the initial expansion of the ignited gases in the explosion chamber.

ROBERT TEMPLE, Jn.