Pin and collar shoring device

A shoring device is disclosed comprising a piston and a cylinder. The piston is axially expanded by compressed gas, whereby the shoring device engages two opposing surfaces. An outer cam collar and a concentrically enclosed inner ring are mounted upon the cylinder end into which the piston inserts. This outer cam collar comprises at least two cam edges, two stop faces and a threaded cam pin within an integral boss. The inner ring comprises a continuous circular indentation as well as a continuous circular inner lip. The outer cam collar and inner ring, together with the continuous circular inner lip and threaded pin, firmly retain the piston. These piston retention features prevent inadvertent rotation and collapse of the piston during use.

BACKGROUND OF THE INVENTION

My invention relates to a shoring device comprising a piston, cylinder, and an outer cam collar combined with an inner ring. More particularly, this invention relates to a shoring device for trenches with a removable rotating outer cam collar. This outer cam collar encloses an inner ring with a continuous circular indentation along the inner ring circumference. This inner ring also comprises an inner continuous circular lip. My new outer cam collar insures that the partially enclosed piston does not rotate during use. My new shoring device is intended for, but not exclusively, public works and construction, rescue and other projects in which shoring is necessary.

As workers shore trenches, they must quickly install shoring to prevent collapse of the trench walls. If shoring is not installed, soil cohesion is lost and it becomes almost impossible to maintain a safe trench. The prior art as best depicted in expired U.S. Pat. No. 3,851,856(Berg) provides a shoring device with an inlet connecting to a pressure source for expanding the device tightly against trench walls. There is also a cylindrical collar mounted on one cylinder end, which receives the piston. This cylindrical collar extends axially from the cylinder and surrounds the proximal piston end.

Still referring to the Berg device, the cylindrical collar comprises two camming surfaces along the cylindrical collar's proximal edge. Subsequent to cylinder pressurization the piston remains extended by the securing of one camming surface with a pin. In addition, a threaded stud abuts and tightens against the cylinder by an attached handle. This threaded stud penetrates the rotating collar and abuts the cylinder after the cam pin is placed against the camming surface.

This abutting threaded stud prevents relative rotation of the cylindrical collar to the cylinder. The threaded stud also locks the cylindrical collar against the pin, thereby preventing the rotating collar from loosening. However, this threaded stud is the only structure in Berg's device which prevents the cylindrical collar from rotating after cessation of the gas pressure.

Furthermore, Berg's threaded stud only contacts one point along the cylinder exterior surface and weakens the cylinder structure after each application. Inevitably, the entire cylinder must be replaced, and this replacement is expensive and time consuming. In contrast, my continuous circular indentation prevents the flat threaded pin furthermost point from skidding along the cylinder surface. The cylinder is not weakened by repeated contract, because the outer cam collar provides the direct contact surface. My outer cam collar is more economical to replace, and protects the cylinder from wear and tear from the threaded pin.

In addition, my inner ring comprises a continuous circular lip which abuts the piston and prevents it from falling from the cylinder or becoming a projectile during operation.

My new inner ring engages one cylinder end, thereby reducing the possibility that the piston will fall from the cylinder during operation. This metal lip abuts the piston to prevent piston lateral movement, which is an important safety advantage which the Berg device does not have.

In my invention the outer cam collar encloses the inner ring and comprises the threaded pin which tightly abuts the circular continuous indentation. The cam edges, together with a straight metal cam pin, prevent counter-clockwise rotation of the outer cam collar. My improved shoring device is engineered to assist underground workers in compliance with the OSHA regulation governing excavations, i.e., 29 C.F.R. 1926.650. This group includes, but is not limited to, sewer contractors, plumbers, gas companies, telephone companies, municipal public works departments and fire rescue services. The principle goal of my shoring device is to provide the necessary physical support which ensures a work environment safe from collapse.

In particular, shoring is the placement of cross bracing and other components within a trench to support trench walls. There are two important theories of shoring: first is the theory of “zero-movement”, in which shoring is designed to prevent wall movement. Shoring is not sufficiently strong to retain a moving wall of soil: it merely prevents a soil wall from initially moving. The second theory of shoring is designated the “Arch Effect.” Shoring is effective because it creates forces as it pushes again trench walls. The network of cross braces and uprights or wale-plates creates an arch effect which retains soil. The shoring and cross bracing actually retains soil, and not the plywood or sheeting.

An operator applies plywood or sheeting to prevent surface soil from falling and injuring a worker. To achieve “zero movement” and the “arch effect,” all gaps and voids must be filled where the cross brace bears on the trench wall. Other than the mandatory inspection for damage before each use and an occasional cleaning, there are no maintenance requirements.

My preferred pneumatic shoring device also comprises a contiguous pressurized gas channel through the cylinder to the piston. In the best mode, this contiguous pressurized gas channel includes a circular channel segment along the lower floor surface of a cylinder rubber end cup.

SUMMARY OF THE INVENTION

My improved shoring device is much safer than, yet remains just as cost effective, as the prior art. The new crucial safety feature comprises an inner ring with a continuous circular inner lip, together with an outer cam collar with a threaded pin within a boss. The outer cam collar concentrically encloses the inner ring, and both the outer cam collar and inner ring concentrically enclose a cylinder which contains a piston.

Release of the outer cam collar in a counterclockwise direction requires the operator to manually twist the threaded pin counter-clockwise, thereby releasing it from a continuous circular indentation along the inner ring exterior surface. The inner ring greatly reduces the likelihood that the piston will become a projectile, because a rubber piston cup attached to a cylinder plug cannot move beyond the continuous circular lip. The inner ring also comprises an inner circular continuous lip which abuts the distal piston end when my shoring device100ais fully assembled. The inner circular continuous lip prevents the piston from becoming a projectile and falling from the cylinder.

The piston is cylindrical in shape and inserts within a cylinder of greater diameter. The piston also comprises a plurality of aligned apertures, into which a straight metal cam pin inserts. This metal cam pin, in combination with the outer cam collar, prevents the piston from retracting into the cylinder, once the air pressure is removed. This straight metal cam pin is inserted into a pair of piston apertures which are closest to the outer cam collar edge. The operator then manually rotates the outer cam collar until it abuts this inserted straight metal cam pin. After this last step, the operator manually rotates the threaded pin within its boss until the threaded pin abuts the floor of the inner ring's circular continuous indentation.

The inner ring encloses the proximal cylinder end and is mechanically attached to the cylinder with at least two screws. Preferably, my inner ring attaches to the cylinder with allen screws (threaded with hexagonal head depressions). With my shoring device, the initial lateral extension of my assembled improved shoring device occurs whenever pressurized air enters the cylinder during a trench application.

During removal of an installed shoring device pressurized air is re-introduced. Next there is counter-clockwise release of the outer cam collar prior to disengagement of the straight metal cam pin and removal of the pressurized air. In actual field operations, the operator does not remove the air pressure from the shoring device until he or she has moved to a safe position removed from the device.

Each shoring device also comprises two removable swivel side plates. One side plate reversibly attaches to the most distal piston end, while the other similarly attaches to the most proximal cylinder end. My removable swivel side plates comprise adjustable set screws for engagement of wood shoring boards or aluminum wale-plates. Each preferred set screw is approximately ¼ inch in diameter, and comprises twenty threads per inch. Each preferred set screw is also approximately one inch in length. However, other side plates or end adapters are also within the scope of my invention, and may be even preferably for primarily vertical or angled applications, such as buildings or vehicles.

In the preferred embodiment my pneumatic pin and collar shoring device also comprises a cylinder plug. Cylinder plug is hollow at its proximal end to accommodate one removable swivel side plate. The remaining approximate one-half of the cylinder plug is solid metal and comprises a continuous channel for compressed air. In the best mode, the cylinder plug comprises a cylinder rubber end cup at its distal plug end. Cylinder rubber end cup more efficiently prevents air leaks from the air channel within metal cylinder plug.

In the best mode, the cylinder end cup comprises apertures and a circular channel, which contribute to the most efficient airflow from cylinder plug distal end. More preferably, air channel segments lie along the lower floor surface of the cylindrical rubber end cup. This circular channel segment comprises a contiguous aperture through which pressurized air from a gas inlet evenly and quickly seals the raised edge of a piston rubber end cup. The prior art cylinder plug comprises a circular groove around the circumference of the metal cylinder plug, and into which groove a rubber o-ring is inserted.

In the best mode, my preferred improved shoring device is assembled by inserting the piston so that its piston rubber end cup initially abuts cylinder rubber end cup. The inner ring is next inserted over the cylinder end until its circular metal inner lip engages the distal cylinder end. The operator then bolts the inner ring is then bolted to the cylinder. The outer cam collar is next positioned so that it encloses the inner ring.

The outer cam collar has limited movement along the cylinder, but it can be manually rotated and then locked to the inner ring with the threaded pin. At least approximately one-third of the longitudinal axial length of the piston must always remain within the cylinder. After the operator fits the outer cam collar over the inner ring, he or she finally inserts the removable swivel side plates at the distal and proximal end of the shoring device.

For pneumatic applications, my pin and collar shoring device is particularly suited for situations in which only one air pressure value is available. Any single specific air pressure value is generally in the range of approximately 115–150 psi (pounds per square inch). For support of a car or building, my shoring device is manually extended until resistance is felt. Then the operator inserts a straight metal cam pin into appropriate piston apertures. He or she then manually tightens the outer cam collar by rotating the threaded pin until the threaded pin tightly abuts the continuous circular indentation.

Accordingly, it is a goal of my invention to provide a more comprehensive reliable anti-rotational mechanism for a piston within a cylinder.

It is another goal of my invention to provide a safer locking mechanism with an outer cam collar in combination with an inner ring, for a pneumatically driven shoring device.

It is another goal of my invention to provide a device which prevents the piston from ejecting from the cylinder.

It is another goal of my invention to provide cast aluminum handles for manual rotation of outer collar.

These as well as other features of my device are described further in the drawings and the detailed description of the preferred embodiment and other embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT AND OTHER EMBODIMENTS

Referring initially toFIGS. 2 and 3of the preferred embodiment, my improved shoring device100acomprises a piston102, cylinder101, an outer cam collar107a, and an inner ring113a. Shoring device100ais particularly suited for shoring of trench walls, by using compressed gas to laterally extend piston102. Shoring device100ais especially suited for situations in which the gas source has only one designated numeric pressure. However, other sources of appropriate lateral force are also within the scope of my invention. My shoring device100ais preferably approximately 43 inches long in its maximum extended configuration, and approximately 33 inches in its most retracted configuration. Three other satisfactory lengths are as follows:approximately 25 inches when fully retracted and approximately 30 inches when fully extended;(2) approximately 45 inches when fully retracted position and approximately 65 inches when fully extended; and(3) approximately 67 inches when fully retracted and approximately 102 inches when fully extended.

Other diameters and lengths are also within the scope of my invention. Circular rubber end cups155b,156infra, add approximately two inches to every model, so that only cylinder and piston length varies.

Still referring toFIGS. 2 and 3of the preferred embodiment, my improved shoring device100acomprises a cylinder101. Cylinder101is hollow, preferably approximately 15 inches in length and approximately 3.0 inches in interior diameter. Cylinder wall101cis preferably approximately one-quarter of an inch (¼″) thick. Cylinder101has a proximal cylinder end104aand distal cylinder end104b.

Cylinder101also comprises a removable swivel proximal cylinder side plate103awhenever shoring device100is fully assembled. Swivel proximal cylinder side plate103ais identical in structure, size and function to removable swivel distal piston side plate103b, infra. Each swivel side plate103a,103bcomprises a plate103e,103fwhich is preferably approximately five inches in length and width. Each swivel side plate103a,103balso comprises a central screw135a,135brespectively, and a central segment136a,136brespectively. Swivel proximal and distal side plates103a,103arespectively also each comprise at least one adjustable first and second set screw120a,120brespectively, for engagement with wood shoring boards and/or aluminum wale-plates175(FIG. 1).

Each central segment136a,136brespectively comprises a first and second swivel groove137a,137brespectively. First and second insert portions138a,138brespectively attach within grooves137a,137brespectively, by their first and second insert ridges139a,139brespectively.

Each groove137a,137bcontaining an insert ridge139a,139brespectively prevents a swivel proximal or distal side plate103a,103brespectively, from swiveling in an unlimited manner. Removable swivel side plates are well known in this particular equipment industry. However, other side plates, base plates or attachments are also within the scope of my invention.

Still referring toFIGS. 2 and 3of the preferred embodiment, at proximal cylinder end104ais proximal side plate detente pin105a. Proximal side plate detente pin105aconnects cylinder101to swivel cylinder proximal side plate103aby insertion through (i) first and second proximal side plate swivel apertures103c,103drespectively and; (ii) congruently aligned first and second cylinder end apertures116a,116b.

First and second proximal side plate swivel apertures103c,103doppose each other at approximately 180 degrees. Cylinder end apertures116a,116balso oppose each other at approximately 180 degrees. Cylinder end apertures116a,116bcan congruently align with swivel apertures103c,103dwhenever swivel proximal cylinder side plate103ainserts into cylinder101. Cylinder end apertures116a,116bare approximately one and ¾ inches from cylinder proximal end104a.

Referring now toFIGS. 3 and 7of the preferred embodiment, approximately three inches from inserted proximal side plate103a, and approximately 90 degrees from proximal detente pin105a, is compressed gas inlet111. Compressed gas inlet111connects shoring device100ato an external source of compressed gas through cylindrical plug155, infra.

As seen inFIGS. 2 and 7, small circular vents112a,112b,112c,112d(generically small circular vents112) for gas exhaust are aligned along a cylinder circumference at intervals of approximately 90 degrees to each other. Small circular vents112are approximately one quarter inch in diameter. In the preferred embodiment there are four small circular vents112, but other numbers are also satisfactory.

Referring now toFIGS. 3,7, and11, cylinder plug155is part of cylinder101, and cylinder plug155is contiguously attached to cylinder101by first and second set screws160a,160brespectively. First and second set screws160a,160boppose each other at approximately 180 degrees along cylinder101. Cylinder plug155abuts proximal cylinder end104aby circular contiguous ledge155a. Metal contiguous ledge155ais also the cylindrical component into which compressed gas inlet111inserts. Cylinder swivels proximal side plate103ainserts into cylinder plug155proximal to circular contiguous ledge155a.

Still referring toFIGS. 3 and 7, the inner diameter of cylinder plug155is approximately 3.5 inches. Cylinder plug wall155fis preferably approximately ⅔ (two-thirds) inch in thickness at proximal plug end154a. Cylinder plug interior155dcomprises a proximal round metal barrier155ewhich abuts fully inserted swivel proximal cylinder side plate103a.

Referring toFIGS. 3 and 7, in the best mode cylinder plug155at distal plug end155qcomprises cylindrical end cup155b. Cylindrical end cup155bcomprises an outer raised circular rim155c, which faces a piston rubber end cup156, infra, within a fully assembled shoring device100. Cylindrical end cup155bcomprises the same shape, dimensions and material as piston rubber end cup156, infra. Cylindrical end cup155babuts piston rubber end cup156by raised circular rim155c, whenever piston102is completely inserted within cylinder101.

Cylindrical end cup155balso comprises a cylindrical end cup floor155dwith centrally located bolt aperture155j. Plug bolt155minserts into bolt aperture155jand thereby attaches distal plug end155qto cylinder end cup155b. Cylinder washer155psurrounds plug bolt155m.

Initially referring toFIG. 9, in the best mode cylindrical end cup floor155dcomprises an upper end cup floor surface169aand a lower end cup floor surface169b. Also referring toFIG. 10of the preferred embodiment, cylinder end cup155bcomprises a lower air aperture158bwithin its lower end cup floor surface169b, and upper air aperture158awithin upper end cup floor surface169a. Lower and upper air apertures158a,158brespectively are integrally connected to each other by (i) a first air channel segment164awithin rubber end cup floor surface169b; and (ii) a short air channel segment164etraversing rubber cylinder end cup floor155d.

As best seen inFIGS. 4 and 9, in the best mode first air channel segment164ais circular, approximately one inch in exterior diameter and approximately one-quarter inch in depth along lower cylindrical end cup floor surface169b. As best seen inFIG. 10, short air channel segment164eis adjacent and parallel to bolt aperture155jwithin end cup floor155d. Short air channel164econnects circular air channel segment164ato upper aperture158a. However, other embodiments of my invention need not comprise a first air channel segment164awhich is circular.

Referring toFIGS. 3 and 7, lower air aperture158ais congruent and contiguous with second air channel segment164bwithin cylinder plug155. Air channel segment164bis adjacent to and parallel to longitudinal midline163of cylindrical plug155, as seen inFIG. 4. In the preferred embodiment, second air channel segment164bis continuously connected to third air channel segment164c. Third air channel segment164cis approximately perpendicular to second air channel segment164b. Preferably both air channel segments164band164care linear in form.

Second air channel segment164bleads towards the outer metal surface of cylinder plug155, and is continuous with gas inlet111. Gas inlet111is continuously connected to an external source of pressurized gas, such as CO2 or air. Consequently when air is introduced from an exterior source, there is a continuous pressurized gas channel through: gas inlet111; third and second air channel segments164c,164b; lower air aperture158b; circular first air channel segment164a, short air channel segment164e; and finally upper air aperture158a.

After passing through this pathway, almost instantaneously this pressurized air seals piston end cup raised circular rim156aagainst inner cylinder wall101cc.FIG. 4illustrates the physical continuity of lower aperture158ain rubber end cup155b, with metal distal cylindrical plug end155q, with respect to bolt aperture155jand adjacent second air channel segment164b.

Referring toFIG. 11for other embodiments, prior art cylinder plug155comprises a singe end aperture155sswhich is continuous with second air channel segment164b. Approximately two inches from cylindrical plug end155qalong a cylinder plug circumference155uis circular groove155t. Circular groove155tcontains an appropriately sized O-ring155v. O-ring155vprevents air leakage from cylinder end plug155. Prior art cylinder plug155is available from Airshore, infra.

Referring initially toFIGS. 2 and 3of the preferred embodiment, piston102is hollow and cylindrical in shape, approximately thirteen (13) inches in length, and approximately two and one-quarter inches in inner diameter. However, other lengths and diameters are also within the scope of my invention. Piston102comprises a piston wall102k, which is approximately ¼-inch (one-quarter) inch in thickness. Piston102is narrower in diameter than cylinder101, into which piston102inserts in a removable manner.

Along its longitudinal axis piston102comprises four linearly aligned parallel sets of piston apertures128a,128b,128c,128d;128e;129a,129b,129c,129d,129e,129f;130a,130b,130c,130d,130e; and131a,131b,131c,131d,131e,131f(generically opposing piston apertures128,129,130,131). Representative apertures128,129,130,131are best seen inFIGS. 3 and 7, and are preferably approximately 1 and ½ inches in diameter.

Each set of piston apertures128,129,130,131is preferably approximately 90 degrees from each adjacent aligned set. However, individual adjacent apertures are preferably aligned at the midpoint of adjacent apertures, as best seen inFIG. 3. Opposing sets128/130and129/131are approximately 180 degrees from each other, so that straight metal cam pin170is inserted through them simultaneously, as best seen inFIG. 7.

Four linearly aligned sets are preferred, but other numbers of linearly aligned sets are also within the scope of my invention. There are also preferably two opposing sets of five apertures per linearly aligned set (128,130), and two opposing sets of six apertures (129,131) per linearly aligned set. However, other numbers of piston apertures are also within the scope of my invention.

Still referring toFIGS. 3 and 7, in a fully assembled shoring device100a, piston102is closed at most distal end102bby swivel piston distal side plate103b. Swivel piston distal side plate103bis attached within piston102by insertion of piston detente pin105bwithin:(i) piston apertures128/130or129/131and(ii) first and second swivel side plate apertures141a,141brespectively.
Piston apertures128/130or129/131and side plate apertures141a,141bmust be congruently aligned with each for insertion of piston detente pin105b.

Still referring toFIGS. 3 and 7, at its proximal end102apiston102is capped by metal piston end wall102c. Metal piston end wall102cis secured to piston102by first and second opposing screws164ff,164ggrespectively. Metal piston end wall102cis flush with piston wall102k, and is approximately one-half inch in thickness at its proximal end.

A piston rubber end cup156is secured to metal piston end wall102cby piston bolt156dextending through metal washer156e. In the center of piston rubber end cup flat circular floor156f(which is preferably approximately three inches in diameter) is piston bolt156d. In other embodiments, piston end cup156comprises identical apertures158and channel segments164to cylinder end cup155b. In fact, in the best mode mass production of end cups155b,156is the most economical approach. However, in these embodiments apertures and channels in end cup156are covered with a large washer because they have no function in piston end cup156. In the preferred embodiment and best mode, piston end cup156comprises no air apertures or air channel segments of any type. Please seeFIGS. 3 and 7.

Circular piston rubber end cup156comprises raised circular rim156a, and raised circular rim156ais preferably approximately one inch in height. Circular piston rubber end cup156immediately flares, and thereby airseals circular raised rim156awhenever compressed gas enters inlet111and flows through air channel segments164and air apertures158a,159b. This air seal occurs by compression of raised circular rim156aagainst interior cylindrical wall surface101ccby pressurized gas.

Referring initially toFIGS. 5 and 7of the preferred embodiment, inner ring113hencloses distal cylinder end104bin my fully assembled shoring device100a. Inner ring113his shaped as a hollow cylindrical segment and has an inner wall surface, an outer wall surface, and a wall thickness. Inner ring113hattaches to cylinder101by first inner set screw113aand second inner set screw113b. Inner set screws113a,113boppose each other at approximately 180 degrees along cylinder101. Inner ring113his preferably approximately three inches in width parallel to the long axis of cylinder101, and approximately twelve and one-half inches in outer circumference. Inner ring113hhas a proximal ring edge113cand a distal ring edge113d, both of which are beveled.

Inner ring113his preferably approximately ¼ inch in thickness at distal ring edge113dand proximal ring edge113c. Referring toFIG. 10, inner ring113halso comprises a metal inner continuous circular lip180at beveled distal ring edge113d. Metal inner continuous circular lip180is continuous with beveled distal ring edge113d, and lip180is approximately perpendicular thereto. Metal inner continuous circular lip180fits over cylinder distal end104band prevents inner ring113hfrom sliding along cylinder101(in addition to opposing inner set screws113a,113b).

Metal inner continuous circular lip180is approximately one-half inch wide, approximately one-half inch in thickness, and approximately three inches in inner diameter in the preferred embodiment. However, other dimensions of circular metal lip180are within the scope of my invention.

Referring toFIGS. 7 and 10of the preferred embodiment, approximately 1 and ⅝ inches above proximal ring edge113clies circular continuous indentation113i. Circular continuous indentation113iis uniform in width (approximately ¾ inch) and depth (approximately ⅛ inch). First and second continuous indentation walls113p,113qrespectively are perpendicular to circular continuous indentation floor113j. First and second continuous indentation walls113p,113qare also the same height as indentation depth (i.e, approximately ⅛ inch). However, other width and depth measurements are also within the scope of my invention.

Referring initially toFIG. 2of the preferred embodiment, outer cam collar107tcan move axially from piston distal end102bto cylinder distal end104b. As seen inFIGS. 3 and 5of the preferred embodiment, after assembly outer cam collar107htcompletely encloses inner ring113h.

Outer cam collar wall107cis preferably approximately one-quarter (¼) inch in thickness and approximately four and one-quarter (4 and ¼) inches at its greatest axial width. In the preferred embodiment, outer cam collar107thas an outer diameter of approximately 13 inches. Outer cam collar107tis approximately four inches wide at its narrowest outer width. However, other widths, diameters and thickness are also within the scope of my invention.

Referring now toFIGS. 6 and 7of the preferred embodiment, outer cam collar107tcomprises a plurality of handles115a,115b,115c, etc. (generically handles115). Handles115are integral oblong components of outer cam collar107t, and preferably are of two types:(i) approximately four and one-quarter (4 and ¼) inches in axial and ⅓ (one third) inch in height (115blength (115b,115c,115e,115f); and(ii) approximately four and one-quarter (4 and ¼) inches in length and one and three quarters (1 and ¾) inches in height (115a,115d).

In the preferred embodiment, there are six handles; four of these six handles are the shorter height handle115. However, other heights, shapes, lengths, numbers and types of handles are also within the scope of my invention. Referring toFIG. 7, handles115are aligned parallel to each other and approximately perpendicular to the midline circumference108of outer cam collar107t. Preferably, approximately 3 and ½ inches separate adjoining handles115b,115c, while approximately 3 and ½ inches separate adjoining handles115eand115f. Outer cam collar107talso comprises a threaded vertical screw176, by which metal cam pin170is tethered to outer cam collar107tby steel lanyard145.

As best seen inFIGS. 6 and 7of the preferred embodiment, proximal outer cam collar edge107ais uniformly round and smooth. Proximal outer cam collar edge107ais preferably approximately one quarter (¼) inch in uniform thickness. Distal cam collar edge107bcomprises180degree-opposing vertical first and second stop faces107f,107grespectively. Continuous with stop faces107f,107gare corresponding first and second sloping cam edges107h,107irespectively. Sloping cam edges107h,107iform cam surfaces for abutting metal cam pin170, infra.

Referring now toFIGS. 7 and 10of the preferred embodiment, outer cam collar107tcomprises inner collar surface107k. Inner collar surface107kcomprises wider circular proximal step167and narrow circular distal step168. Each step167,168is axially aligned along cylinder101, so distal narrower step168is nearest distal piston end102bin assembled shoring device100a. Wider proximal step167comprises a wider inner diameter. This wider diameter allows outer cam collar107hto slide over(i) piston102, and then(ii) inner cam ring113huntil circular metal lip180engages narrower distal step168.

Wider circular proximal step167is approximately four inches in interior diameter and approximately preferably 2.8 inches in interior axial length. Circular distal narrower step168is preferably approximately three inches in interior diameter and approximately 2.5 inches in interior axial length. Without narrow circular distal step168, outer cam collar107tslides along cylinder102prior to adjustment with threaded cam pin185, infra.

As best seen inFIG. 7, between first and second short handles115b,115crespectively is an abutting element which penetrates outer cam collar107t. In the preferred embodiment, abutting element comprises a threaded pin181which is removable from an integral threaded boss181a. Threaded pin181comprises a pin handle181bwhich is approximately three and one-half inches in length. Threaded stem181cinserts into threaded interior of handle181band is further attached with suitable solder. Integral threaded boss181ais approximately one inch in diameter and one-half inch in height.

Threaded stem181cis approximately one inch in length and approximately three-eighths inch in diameter at furthermost stem point181e. Threaded stem181cpenetrates cam collar wall107cthrough threaded boss181aand threaded wall aperture181d. When threaded stem181csufficiently protrudes through threaded wall aperture181d, furthermost stem point181etightly abuts indentation floor113j(whenever the operator manually turns threaded pin handle181das tightly clockwise as possible).

Other lengths and diameters of threaded pins181are also within the scope of my invention. To release threaded pin181, the operator turns threaded pin handle181bcounter clockwise, so furthermost stem point181ereleases from indentation floor113j. After release, the operator can rotate outer cam collar107tor move it along piston102. Because indentation floor113jis continuous and smooth, threaded pin181can abut within the entire width and circumference of indentation floor113j.

In addition my inner ring design enables the operator to loosen the threaded pin181from contact with indentation floor113jwhile threaded in181remains within the continuous indentation walls113p,113q. This feature allows the outer cam collar107tto rotate during transport or installation while eliminating inadvertent movement of outer cam collar107.

Prior Art U-Shaped Removable Side Plate570

Referring now toFIG. 12, prior art U-shaped removable side plate570is useful for trench applications of preferred pneumatic shoring device100a. It also attaches to vertical and angled non-pneumatic embodiments of shoring device100awhich support collapsed buildings and unstable motor vehicles. U-shaped removable side plate570attaches to proximal cylinder end104aor distal piston end102b. Removable U-shaped side plate570comprises a circular (in cross-section) solid metal base571. Solid metal base571supports U-shaped flat plate573upon a flat horizontal supporting surface8. Solid metal base571also comprises a first and second solid metal base apertures571a,571brespectively. Solid metal base apertures571a,571boppose each other at approximately 180 degrees.

Whenever U-shaped removable side plate570inserts into distal piston end102bor proximal cylinder end104a, the operator congruently aligns apertures571a,571bwith cylinder apertures116a,116bor piston apertures128/130,129/131, as the case may be. The operator then inserts metal detente pin151jthrough these congruently aligned four apertures, to secure removable U-shaped side plate570within either cylinder end104aor piston end102b. U-shaped removable side plate570similarly inserts into distal piston extension end500bor piston adjustable add-on segment520.

Still referring toFIG. 12, solid metal base571has an upper circular metal base surface571g, to which U-shaped flat plate573attaches by large allen screw/washer573g. U-shaped flat plate573comprises a flat horizontal upper surface573a. Upper surface573has small first, second, third and four base apertures573b,573c,573d,573erespectively. U-shaped flat plate573is approximately 0.25 inch in thickness. Piston extensions500and piston add-on segments520are interchangeably attached to removable U-shaped side plate570or removable swivel side plates103a,103b.

Still referring toFIG. 12, U-shaped flat plate573has a first opposing edge574aand second opposing edge574b. Integrally attached to each edge574a,574bis a first and second upwardly protruding side wall575a,575brespectively. Each upwardly protruding side wall575a,575bis approximately 2.0 inches in height and approximately 3/16 inch in thickness. Upwardly protruding side walls574a,575bengage wooden boards within a trench or grasp a wooden beam of varying widths. Representative widths (and lengths) of wooden boards include: six inches by six inches; eight inches by eight inches, or four inches by four inches. However, other sizes and dimensions are also within the scope of my invention.

Still referring toFIG. 11, each upwardly protruding side wall575a,575bcontains first and second small side wall apertures576a,576band third and fourth small side wall apertures577a,577brespectively (generically small side wall apertures576,577). Small side wall apertures576,577are each located at upper corners of the corresponding upwardly protruding side wall575a,575b, as seen inFIG. 11. Apertures573and small side wall apertures576,577provide insertion points for nails or screws into the supported object, thereby reducing inadvertent movement. Small roll pin573jadjacent to alien screw573also attaches solid metal base571to U-shaped flat plate573.

However, other embodiments of U-shaped removable plates570are also within the scope of my invention.

Assembly of One Shoring Device100a

Each shoring device100ais assembled exterior to a trench or structure to be shored or propped. The operator initially bolts rubber piston end cup156to proximal piston end102a, while cylinder circular end cup155bis bolted to distal end155iof cylinder plug155. Cylinder plug155is then inserted into proximal end104aof cylinder101and attached thereto with screws160a,160b. The operator then inserts piston102into distal end104bof cylinder101until cylinder rubber end cup155babuts piston circular rubber end cup156.

The operator now slides inner ring113hover cylinder101until metal continuous inner circular metal lip180engages cylinder distal end104b. The operator attaches inner ring113hto cylinder101with two screws113a,113b, and then positions outer cam collar107tover inner ring113h.

As the last assembly step, the operator inserts removable swivel endplate103ainto proximal cylinder end104a, and inserts removable swivel endplate103binto distal piston end102b. The operator aligns first and second cylinder apertures116a,116bto congruently align with proximal swivel side plate apertures103c,103d. He or she then takes a proximal swivel side plate detente pin105aand inserts it through properly aligned side plate apertures103c,103dand cylinder apertures116a,116b.

Swivel side plate detente pin105anow attaches proximal swivel side plate103awithin cylindrical plug155. The operator inserts distal swivel side plate detente pin105bthrough congruently aligned opposing piston apertures128/130or129/131and second swivel side plate apertures141a,141b. Distal swivel piston side plate detente pin105bnow attaches removable distal swivel side plate103bto distal cylinder end102b. Tethered cam metal pin170is preferably temporarily inserted through an empty piston aperture, to prevent dragging and dangling outside the shoring area.

My improved pin and collar shoring device100ashould never be operated except under lawful conditions and at the site of the shoring operation, infra. My improved shoring device100aoperates in an extended position in which pressurized air initially forces piston102laterally from cylinder100. Other applications such as vehicles and buildings require manual extension, as discussed supra.

To maintain this extended lateral piston position in pneumatic and non-pneumatic applications, the operator first manually rotates outer cam collar107hclockwise, until a specific aperture128,129,130,131is closest to sloping cam surface107ior107h. Please seeFIG. 7(129a/131a).

He or she then inserts tethered metal cam pin170within that closest piston aperture and through its 180-degree opposing piston aperture. For example, if the operator inserts straight cam metal pin170through piston aperture128b, then straight cam metal pin170also inserts within opposing piston aperture130b. The operator continues to rotate outer cam collar107tclockwise until straight metal cam pin170firmly abuts the closest sloping cam surface107ior107j, as the case may be. After abutment occurs, the operator obtains a maximum tight fit by rotating threaded pin181until he or she detects the abutment of furthermost point180ewith indentation floor113d.

Without additional pressurized air flowing to my shoring device100acylinder101and piston102remain laterally extended, This extension continues because outer cam collar107tand inner cam ring113hprevent counter-clockwise rotational piston movement and subsequent slippage from cylinder101. To disengage outer cam collar107tthe operator rotates outer cam collar107tin a counter-clockwise direction and releases threaded pin181by rotating pin handle181bcounter clockwise. He or she continues to rotate outer cam collar107tuntil straight metal cam pin170no longer abuts either sloping cam surface107i,107j. The operator then removes straight metal cam pin170.

Vent holes112within cylinder wall101d, release gas from cylinder101whenever piston102extends from cylinder101sufficiently for piston rubber end cup156to pass beyond vent holes112. As a result of vent holes112, no further extension of shoring device100aoccurs, because the air pressure dissipates. The preferred number of vent holes112is four, but other numbers are also satisfactory.

Installation of Multiple Shoring Devices100ain an Excavation or Trench

The operator always installs a plurality of my improved shoring devices100ain progression from the top of the trench to the bottom of the trench. For horizontal and vertical placement requirements of trench supports for pneumatic shoring devices100a, please see attached Exhibits A (Timber and Plywood) and B (Aluminum Wale-Plates). The best mode installation and removal procedure proceeds as follows:

1. The operator initially determines appropriate reinforcement measurements according to 29 C.F. 1926.652 (Federal Register, Vol. 54(209): 45961–62, Oct. 31, 1989) (Requirements for protective systems). Under this regulation, the engineer's data in Exhibits A and B determines the horizontal and vertical spacing between wale plates or wood supports, according to trench depth and soil type. However, these measurement in Exhibits A and B are only application to my preferred embodiment shoring device100a. The measurements must be recalculated for other embodiments or sizes of shoring device100a, as well as other soil types and trench depth. Soil type A-25 comprises cohesive soils with unconfined compressive strength of at least 1.5 tons per square foot (uch as clay and cemented soils). Class B-45 is cohesive soil with an unconfined compressive strength greater than 0.5, but less than 1.5 tons per square foot (such as sandy loam and city loam. Department of Labor, 29 C.F.R. 1926 (Federal Register, Vol. 54 (209): 45939, Oct. 31, 1989).

(a) The installer can position a wooden board which is approximately 2 inches thick by 10 inches wide (designated as an “upright” in this industry) on each opposing trench wall surface. The operator can force these boards further into each trench wall using pressurized air, infra. Please seeFIG. 1. The length of these boards varies, depending upon the dimensions of a trench or other application.

(b) In other circumstances, the operator can position an approximately 12-inch tall aluminum wale-plate at each end of shoring device100a. These wale-plates are approximately six inches wide and approximately 2 and ½ inch in thickness, and they eliminate the need for upright wooden boards.

(c) The operator then selects the proper size and number of shoring devices100arequired to shore or prop the trench effectively. The installer positions plywood, timber uprights or aluminum wale-plates as required after he has descended into the trench, infra.FIG. 1illustrates a plurality of shoring devices100ain a trench, and in which shoring devices100asupport first and second wooden shoring boards and/or aluminum wale-plates.

2. The operator next determines that outer cam collar107tis properly positioned over inner cam ring113h. Prior to installation, the installer will often place tethered straight cam metal pin170into one piston aperture128,129,130,131to prevent straight cam metal pin170from dangling. However, the installer must remove tethered straight cam metal pin170prior to pressurizing shoring device100a, or straight cam metal pin170will prevent full extension of piston102.

(a) The installation pressure is the air pressure required to expand piston102laterally from cylinder101, thus forcing the upright wooden boards and/or aluminum wale-plates into opposing trench walls with attached swivel side plates103a,103b. The preferred embodiment of my shoring device100arequires an installation pressure of approximately 115 to 225 pounds per square inch in the best mode.

(b) Under this compressed gas or air pressure, piston102extends laterally and distally until both removable swivel side plates both103a,103bbear against the wooden shoring boards and/or or wale-plates. First set screw120aand second set screw120bquickly engage the wooden shoring boards or aluminum wale-plates after introduction of pressurized air, thus preventing board or wale-plate random movement.

(c) In the best mode, there are at least two shoring devices in one trench whenever shoring devices100aare the sole protection from wall collapse. For trenches with a depth greater than eight feet, in the best mode there should be a shored length of trench at least equal to its depth. For example, a trench that is twenty feet long and nine feet deep should have at least nine feet of its length shored, or propped, by my shoring device100a.

3. The operator next places a ladder in the trench and descends until his waist is even with the top of the trench. Third persons outside the trench assist by lowering the shoring device100ato the descending operator with either a rope or webbing.

The installer now positions shoring device100ato the required or desired depth (i.e., no deeper than two feet for the uppermost initial placement, and then no greater than four feet thereafter) within the trench, but he himself does not descend into the trench below his waist. The installer levels shoring device100ato the horizontal (i.e., parallel to the floor of the trench) and authorizes air pressure to shoring device100afrom third persons. This air pressure results in immediate lateral extension of piston102within cylinder101.

4. Vent holes112give an audible indication whenever piston102, which must remain within cylinder101, reaches its maximum extended position. This indication occurs whenever approximately ⅓ of piston102remains within cylinder101At this time, if additional shoring device10alength is required, then the operator obtains a shoring device with a greater lateral extension.

(a) With piston102now fully extended from applied air pressure, the operator rotates outer cam collar107aclockwise, until a piston aperture128,129,130, or131is closest to a sloping cam surface107i,107.

(b) He oro she then inserts a straight metal cam pin170through this piston aperture and its 180-degree opposing counterpart, such as128c/130c,129b/131b, as examples. The operator continues to rotate outer cam collar107auntil straight cam metal pin170firmly abuts either sloping cam surfaces107ior107j.

5. Immediately after straight metal cam pin170engages either sloping cam surface107i,107j, the operator continues to rotate outer cam collar107auntil collar107acan no longer move clockwise. This engagement prevents piston102from rotating counter-clockwise and retracting into cylinder101. This result occurs because mechanically engaged inner cam collar107tand inner ring113h(i) tightly abut each other when rotated threaded cam pin181lodges against indentation floor113j; and (ii) are simultaneously tightly locked against piston102and cylinder101. This combination also presses stop faces107i,107jand cam surfaces107fand107gdirectly against piston102.

Inner ring113halso grasps piston102directly and is braced against counterclockwise rotational force by screws113a,113bwhich connect inner ring113hto cylinder101. Please seeFIG. 7. In addition, straight cam metal pin170prevents piston102from retracting into cylinder101or collapsing onto the trench floor.

6. Once outer cam collar107tand inner ring113htightly abut through straight metal pin170and threaded pin181, the operator signals third persons to remove exterior air pressure from the now extended shoring device100a. The air hose is then removed from the leveled shoring device100ato attach to another shoring device100a. This particular shoring device100ais now in its extended longitudinal position, and swivel side plates103a,103bengage opposing wood shoring boards and/or aluminum wale-plates with set screws120.

7. Now that first shoring device100ais installed, the installer can further descend the ladder within the trench, until his waist is even with the level of this initial installed shoring device100a. He then prepares to install a second shoring device100aat a greater depth within the same trench. As the operator progresses deeper into the trench, his next “level of protection” is waist height with last installed shoring device100a.

In the best mode of applying improved shoring device100a, the operator uses two-inch by ten-inch Douglas fir timber uprights or aluminum 12-inch wale-plates. Aluminum wale-plates are positioned horizontally or vertically. Plywood, timber uprights, and 12-inch wale-plates are all satisfactory, as long as these items continuously contact trench walls with no gaps or voids. Plywood sheeting is required in all trenches, regardless of depth, if the operator observes sloughing or raveling (movement of soil around or between shoring elements).

In the best mode and preferred embodiment, shoring device100ais strongest whenever the operator positions it completely horizontally within the trench. However, other embodiments support structures for which a shoring device100ais most effective when positioned vertically. With these embodiments, base plates in place of swivel side plates103a,103bare necessary for vertical positions. For example, with a single or a plurality of shoring devices100a, a vertical position (or small angle from the vertical) from the supporting flat surface is recommended for shoring of a vehicle or structure such as a house. In the preferred embodiment shoring device100ais installed at an angle which deviates from the horizontal no more than 15 degrees.

Depending upon the circumstances, the engineer may require plywood in addition to either wooden upright boards or wale-plates. Where plywood is necessary, it is preferably 1 and ⅛ inch Douglas fir or 14-ply white birch. Douglas fir is a tree species, while a “number 2” designation refers to the wood quality and grade. These particular designations are well known in the rescue industry, as well as the lumber industry. The plywood must be at a minimum: 1 and ⅛ inch thick, approximately four feet wide and approximately eight feet long.

Alternatively, the installer can use the 14-ply (fourteen layers glued or laminated together) white birch plywood, which is approximately ¾ inch thick, four feet wide and eight feet in length. Other dimensions are also within the scope of my invention, as the operator is not limited to a certain plywood size.

Removal of Multiple Shoring Devices100awithin an Excavation or Trench

In a reverse chronology of the installation described immediately supra, the operator always removes a plurality of shoring devices100afrom the trench bottom to the upper trench edge. In this manner, the operator remains waist high to the last extended installed shoring device100awithin a trench. An operator at this “level of protection” is either completely exterior to the trench or at the level of the next highest fully installed shoring device100a. In the proper level, the operator next follows these steps:

1. Prior to disengagement and removal of each shoring device100a, air pressure is re-introduced through gas inlet111by a method well known in this particular industry. After re-introduction of air pressure, the operator releases threaded pin181by turning handle181bcounter-clockwise and removing threaded stem180from contact with indentation floor113d. Each shoring device100arequires the same pressure upon removal from the trench as it did during installation.

2. With threaded pin181no longer in contact with indentation floor113d, the operator rotates outer cam collar107tcounterclockwise until straight metal cam pin170no longer abuts sloping cam surface107f. He or she then removes straight metal cam in170to retract shoring device100a.

In sum, the operator removes the shoring device100awith the same procedures as for installation, except that he or she need not rotate outer cam collar107clockwise. Instead, the operator rotates threaded pin181by handle181bcounterclockwise to release outer cam collar107, thereby requiring less exertion.

(a) Shoring device100adoes not collapse at this point, because the air pressure provides continuing extension of piston102. Without the continuing air pressure to a shoring device100awithout pin support, the trench wall could collapse.

(b) With the air pressure still connected to gas inlet111, the operator now ascends the ladder to either remove another shoring device100a, or exit the trench. After the operator is in a safe position, the air pressure through gas inlet111is removed, and third persons assist in lifting this particular shoring device100afrom the trench with rope or a webbing material.

Wherever possible, back filling replaces soil which was removed from a trench prior to the above-described operation. In the best mode of using my device100a, back filling is recommended after all shoring devices100aare removed from the trench, and after the trench operation is complete. In the best mode, for trenches with a depth greater than eight feet, the length of the trench shored should equal the actual trench depth. Back filling can also be by concrete or wooden blocks, and is completed as each shoring device100ais removed.

Operators should not use my shoring device100ain trenches, which are wider than 15 feet or at a depth other than five to twenty feet. For depths greater than twenty feet, a registered engineer should be consulted for the appropriate wood or wale-plate shoring requirements.

Straight cam metal pins170have round “key rings” at the upper end of each pin to prevent slippage through piston102. The recommended models are:(a) ⅝ inch by 3.5-inch detente ring pins105cwith a collar (12L14Carbon Steel Zinc w/ yellow chromate finish or stainless steel), where ⅝ inch is the diameter of the pin shaft;(b) ⅝ inch by four and ¾ inch ring pin with collars (Grade 5, 1144 carbon steel with zinc and yellow chromate finish); and(c) 5/32×1 and ¼ inch, 4–20 stainless steel slotted spring pin. Detente pins105a,105bwith small detente beads45(SeeFIG. 3), are preferably made of carbon steel or stainless steel.

These 356-T components are made by initially pouring molten metal into a mold and are designated in the industry as “sand castings.”

The preferred material for cylinder101is aluminum type 6061-T6, which is extruded, and the dipped in cold water during a process well known in this particular industry. The pistons102and wale-plates are also of the 6061-T6 variety.

The above is a description of the preferred embodiment of my improved shoring device100, as well as the best mode of its application. However, these skilled in the art may envision other possible variations within the invention's scope, by changing the dimensions and shapes of its components. Accordingly, since my invention is possible in other specific forms without departing from the spirit or essential characteristics thereof, the embodiments described herein are considered in all respects illustrative and not restrictive.

All changes, which come within the meaning and range of equivalency of the claims, are intended to be included therein. As such, this above discussion describes the preferred embodiment, but in no way limits the scope of my invention. In addition, the detailed description of my attachments and extensions in no manner limits the spirit or scope of additional accessories, which are compatible with the scope of my invention.