US3917225A

US3917225A - Carpet stretcher improvements

Info

Publication number: US3917225A
Application number: US501667A
Authority: US
Inventors: Buford L Payson
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-08-25
Filing date: 1974-08-29
Publication date: 1975-11-04
Anticipated expiration: 1992-11-04

Abstract

Improvements in carpet stretchers are described which employ an extendible coupling assembly between the stretcher base and the conventional pole assembly or a base block. The extendible coupling assembly comprises a tube and bar assembly which telescopes in the stretcher base tube with lock means carried by the base tube to releasably secure the bar at any extension thereof. In one embodiment, a single locking collar is used, preferably with a remote, cable release. In another embodiment, two locking collars are used, one of which bears the pivot connection for the stretcher link member. This embodiment provides a stepping action which permits the tube and bar assembly to be extended by pumping of the stretcher handle. Another improvement also disclosed is the use of a pivoting head having a forward pivot point.

Description

United States Patent [191 Payson CARPET STRETCHER IMPROVEMENTS [75] Inventor: Buford L. Payson, Garden Grove,

Calif.

[73] Assignee: Robert E. Strauss, Orange, Calif.

[22] Filed: Aug. 29, 1974 [21] Appl. No.: 501,667

Related US. Application Data [63] Continuation of Ser. No. 291,799, Aug. 25, 1972, which is a continuation-in-part of Ser. Nos. 173,779, Aug. 23, 1971, Pat. No. 3,693,936, and Ser. No. 212,127, Dec. 27, 1971, Pat. No. 3,692,278.

[52] US. Cl. 254/60; 254/62 [51] Int. Cl. A47G 27/04 [58] Field of Search 254/60, 62, 63; 287/58 CT [56] References Cited UNITED STATES PATENTS 2,108,506 2/1938 Owens 254/62 2,160,134 5/1939 Fanning 254/63 2,806,723 9/1957 Fairclough 287/58 CT 3,300,182 l/l967 Bussard 254/62 ful- Primary ExaminerAl Lawrence Smith Assistant Examiner-Robert C. Watson Attorney, Agent, or Firm-Robert E. Strauss [57] ABSTRACT Improvements in carpet stretchers are described which employ an extendible coupling assembly between the stretcher base and the conventional pole assembly or a base block. The extendible coupling assembly comprises a tube and bar assembly which telescopes in the stretcher base tube with lock means carried by the base tube to releasably secure the bar at any extension thereof. In one embodiment, a single locking collar is used, preferably with a remote, cable release. In another embodiment, two locking collars are used, one of which bears the pivot connection for the stretcher link member. This embodiment provides a stepping action which permits the tube and bar assembly to be extended by pumping'of the stretcher handle. Another improvement also disclosed is the use of a pivoting head having a forward pivot point.

15 Claims, 7 Drawing Figures US. Patent Nov. 4, 1975 Sheet 2 0f 2 FIG 7 CARPET STRETCI-IER IMPROVEMENTS DESCRIPTION OF THE INVENTION This application is a continuation of my copending application Ser. No. 291,799, filed on Aug. 25, 1972 which is a continuation in part of my prior applications Ser. Nos. 173,779, filed Aug. 23, 1971, now US. Pat. No. 3,693,936 and 212,127, filed Dec. 27, 1971, now US. Pat No. 3,692,278.

This invention relates to carpet stretchers and, in particular, to carpet stretchers having improved compactness and versatility.

The invention described and claimed in the aboveidentified parent application comprises a carpet stretcher having ratchet means associated with its extendible head mechanism and remotely controlled pawl means to lock the head at any desired extension thereof.

The aforementioned stretchers are a substantial improvement because they eliminate the necessity to set the stretcher head to precisely the degree of stretch sought in the carpet. In particular, it is desirable to have a carpet stretcher having a capacity for automatic extension with hand release means. It is also desirable to have a carpet stretcher which permits an infinite number of settings for locking the position of an extendible coupling between the stretcher and tube or base block. For ease of operation, it is desirable that means be provided for the locking and unlocking of the extendible coupling extension on the stretcher handle so that the stretcher can be controlled entirely with a single hand operation. Another objective is to provide a stretcher having a miminum length and size to permit its use in narrow hallways and corridors.

Some of the aforementioned objectives are provided by prior stretchers, e.g., the Master Stretcher of R- berts Consolidate Industries has capability for infinite settings of the head extension and a greater length of extension than conventional stretchers. This stretcher. however, sacrifices compactness and ease of operation.

The improved carpet stretchers of this invention utilize an extendible coupling member and comprise a handle, a head assembly, a base tube. a bar telescopingly mounted thereon, and lock means carried by the base tube which is movable between locking and release positions with spring means biasing it into the locking position. The base of the stretcher can be connected to the usual array of stretcher appliances such as a base block or a tube extension since the bar has attachment means for removable engagement of these appliances.

In one embodiment. the lock means comprises a single collar which surrounds the sliding bar with release means that is preferably linked by a cable to a remote trigger carried on the stretcher handle.

In another embodiment. the lock means comprises a pair of locking collars with the rear pivot of the link member of the stretcher secured to the rearmost collar. its forward pivot connected to the handle. and the stretcher head fixedly secured to the stretcher base tube. The rear collar and link member pivot support are reciprocably carried on the base tube so that a limited freedom of reciprocation is provided. permitting the rear collar to he slid forward on the bar. which is locked against movement by the forward collar. as the handle is raised and locked thereto as the handle is dc pressed. Depressing of the handle forces the bar and LII coupling member assembly rearwardly as the forward collar slides over the bar. In this fashion, a stepping action of the collars on the bar occurs and the bar and coupling assembly can be pumped rearwardly by the handle. Lifting of the handle disengages the locking action of the rear collar and releases tension applied to the carpet. Full release means are also provided to disengage both collars and thereby free the bar for return or retraction within the base tube.

These improvements in stretcher construction are most preferably combined with a pivotal stretcher head which has its pivotable connection to the stretcher at a forward or leading portion of the head.

The invention will now be described by reference to the FIGURES of which:

FIG. 1 illustrates a stretcher of the invention using a single collar;

FIG. 2 illustrates the stretcher embodiment employing two collars; v

FIG. 3 is a top view of the head assembly of FIGS. 1 and 2;

FIG. 4 illustrates a simple version of the invention; and

FIGS. 5-7 illustrate another head assembly.

Referring now to FIG. I, the stretcher is shown as comprising a head assembly formed of a plate 12 bearing teeth 14 for engagement with the carpet. an adapter 16 bearing pin 18 which serves as a pivotal support for hand lever 20 and a shaft, tube or rod 22 is fixedly engaged thereto. The handle is fulcrumed at an intermediate point by link member 24 which is secured thereto with pin 26. The opposite end of link 24 is piv otally secured to the stretcher base, tube 28 by a U- shaped bracket 30 which is secured to base tube 28 by screw 32 and which provides upright ears that are bored to receive pin 34. The rear end of tube 22 is slidably engaged in a telescoping fit with receptacle means carried by the forward end of base tube 28.

As previously mentioned, the stretcher is provided with an extendible coupling assembly which telescopes in the stretcher base tube 28. This coupling assembly comprises a bar in the form of rod 36 which has coupling means, stud 38, for removeable attachment to tube 40. Tube 40 bears a leading plate 42 with a central aperture 44 and a second plate 46 with a tapped bore 48. Alternatively. a solid cylinder with a central bore for rod 36 can be used. The tube 40 is passed over rod 36, which fits through aperture 44, and is turned onto stud 38. The opposite end of tube 40 bears conventional tube coupling means such as a pair of spring biased buttons, not shown.

The fore end of the coupling assembly, rod 36, extends through a bushing 50 that is supported at an intermediate point along base tube 28. Tube 28 bears receptacle means for tube 22 in the form of a short length of a concentric tube 52 which is secured within tube 28 by fore plate 54 and aft sleeve 56. Bushing 50 is supported by tube 52 and. preferably. is manufactured of bronze or of an oil impregnated sintered metal.

The tube 22 which is fixedly carried by adapter 16 and is part of the head assembly 10 is slidably mounted in base tube 28 by the concentric tube 52 which surrounds the tube 22 and provides an annular recess for the reciprocation of tube 22 as lever 20 is moved up and down.

The free end of rod 36 is preferably tapered. as shown. to facilitate manufacture and bears a stop means such as a snap ring 58 which fits in a peripheral groove near the end of the rod. This ring prevents removal of rod 36 through bushing 50.

The extendible coupling means also comprises a lock means that freely permits slidable extension of rod 36 in a rearward direction but which locks rod 36 against retraction or return in base tube 28. The lock means comprises collar 60 which has an aperture 62 at an inclined angle to its face of from 8 to about to provide areuate chamfers which can grip rod 36. The collar has a radially extending projection or finger 64 which extends through a slot in tube 28 and provides a pivotal retention of collar 60 in tube 28. The opposite side of collar 60 bears an axial projection or foot 66 which serves as an abutment for engagement by the lock release means also incorporated in the stretcher.

Resilient means to bias collar 60 into a locking position such as compression spring 68 and spring retainer 32 in theform of a cap with a central aperture about rod 36 are provided. The annular skirt of cap 32 is fixedly secured to the inside surface of base tube 28 by suitable means such as set screws, not shown.

The lock release means comprises washer 70 which is bent to provide a lever action. The washer is secured at the bend line by screws, not shown, which are threaded into the rear face of bushing 50. The upper end of washer 70 is attached to the end of cable 72. Resilient means, c.g., compression spring 74 is biased between the rear face of sleeve 56 and the forward face of washer 70 to urge the lower end of the washer away from foot 66 on collar 60. The sleeve 56 can be bored for passage of cable 72 and counterbored to provide a seat for spring 74. Cable 72 extends along the annulus between

concentric tubes

28 and 52 and through an ap erture in plate 54. The cable serves as a mechanical link from the lock release means to the remote trigger means 76 which is pivotally mounted adjacent hand grip 78 on handle 20. When trigger 76 is depressed. the cable is withdrawn against the tension of spring 74, flexing washer 70 against foot 66 and swinging the lower end of collar 60 rearwardly so that the arcuate chamfers of collar 60 are removed from engagement with rod 36, thereby freeing rod 36 for retraction into the base tube 28. Tube 28 can also bear abutment 80 fixed to its outer surface adjacent projection 64. The abutment can be bored and tapped and a set screw 82 turned into the bore to provide an adjustable bearing for the pivot point for collar 60, thereby providing accommodation for wear of the arcuate chamfers of the collar and/or of the surface of rod 36.

FIG. 2 illustrates the embodiment of the invention which employs a pair of locking collars that provide a stepping action mechanism. The elements in FIG. 2 which are identical to those described with regard to FIG. 1 are identified with the same numerals and their description is not repeated in this discussion. In this embodiment, tube 22 is fixedly secured within base tube 29 by suitable means such as welding or set screws through plate 54. The rear of link member 25 is pivotally secured to radial projection 65 of the rearmost collar 61. Collar 61 is otherwise identical to collar 60, previously described.

Preferably, link member 25 is a channel to permit it to fit over

abutments

80 and 81 and handle is also formed into a channel to permit it to fit over link member and

abutments

80 and 81 when fully depressed.

Tube 29 has a slot 34 cut along its top wall through which projection 65 of collar 61 extends. This slot ex- 4 tends for a distance of from about /2 to 2 inches, preferably to about 1 inch. The collar is biased forward by spring 69 which bears against spring retainer 33. The retainer is fixedly secured to the inside wall of tube 29 by suitable means such as set screws, welding, etc; Spring 69 is preferably of greater length than spring 68] to permit reciprocable movement of collar 61 along the 1 distance of the slot in tube 29.

FIG. 2 also illustrates the conventional button means for engagement with the stretcher accessories such as a pole unit, wall block, etc. The rear of tube 40 is bored with opposite apertures and buttons 90, which are on the ends of bifrucated spring means 92, are inserted through these apertures. The resilient spring 92 biases the buttons radially outwardly so that a mating tube, of

slightly greater diameter, can be slipped over the end of tube 40 and the buttons 90 will snap into matchingapertures in the mating tube or in a base block.

The stretcher shown in FIG. 2 employes the pairof locking collars as a stepping mechanism for extension of rod 36. The stepping action is obtained by up and down movement of handle 20. As the handle is raised,

collar 61 is slid forward on rod 36 which is restrained against forward movement by collar that is locked thereto. When the handle 20 is depressed, collar 61 locks to the rod 36 and the resulting rearward movement of collar 61 in slot 34 will drag the rod 36 through collar 60. In use, rod 36 is secured by tube 40 to a fixed support such as a base block or the end of a pole assembly and depressing handle 20 will cause the stretcher unit to move forward, imparting a stretch to carpet engaged by teeth 14.

The forward lock collar 60 on rod 36 can be released by depressing trigger 76 in the same manner as with the stretcher of FIG. 1. The rearmost collar 61 can be unlocked to permit retraction of rod 36 in tube 29 by raising handle 20 into its full upright position. This pulls foot 67 of collar 61 against the rear of spring retainer 32 and tilts collar 61 against the bias of spring 69 and into the unlocked position. This movement also forces foot 66 of collar 60 against washer 70 and similarly un-* I I locks collar 60. Rod 36 can then be freely moved in either direction in tube 29.

FIG. 3 shows a top view of the stretcher head assembly of FIGS. 1 and 2. The head plate 12 can have a polygonal shape which is popular in the stretcher indus try. The top surface of the plate can have a raised lip 13, approximately one-eighth inch high, aboutits periphery and two outboard bosses, 15 and 17.. The bosses are bored and tapped from their underside and thumbscrews, not shown, can be turned in the bores to provide adjustable stops that provide a controlled variation in the depth that the teeth will penetrate into the carpet.

Plate 12 has a central bore which is preferably located fore of the middle of the plate and shaft 19 (see FIG. 1) extends upwardly through this bore. The lower end of shaft 19 has a head which supports plate 12 and its upper end is bored and tapped to receive the threaded end of thumbscrew 23.

Adapter 16 has a central bore with a bushing .21, preferably of Nylon, which is fitted into this bore. The bushing 21 can have a lip at its lower end to retain it in the bore. Shaft 19 projects upwardly through the bore and thumbscrew 23 is used to retain the plate 12 in a pivotable engagement to adapter 16. A transverse bore 25 with set screw 27 can be provided that projects into I a bearing relationship against bushing 21. Adjustment of set screw 27 provides controlled variation in the frictional engagement of shaft 19 by bushing 21.

FIG. 4 shows a cross sectional view of a simplified extendible coupling which can be used between a power unit of a carpet stretcher and its pole unit. The tube 22 of the head assembly of the power unit projects into the sliding lock assembly and terminates therein with a collar or piston 100 which is secured to the tube by means such as threads, set screws, etc. This collar can suitably be Teflon or Nylon or a similar plastic having a low coefficient of friction.

The pole extension 102, which is shown at the opposite end of the assembly, has a plate 104 secured thereto and a threaded bore 106 extends through the center of this plate. The pole extension is shown disconnected from stud 108. During use of the stretcher. the extension is slipped into tube 110 until it engages stud 108 and is assembled by turning it onto this stud.

Tube 22 is secured within the assembly by end sleeve 112 which has a forward rim 114 which serves as a stop for outer tube 110 and concentric tube 116. The forward movement of tube 22 is limited by spacer sleeve 118 which engages against the forward face of collar 100 when the tube 22 is moved to its most forward extension. A shaft 122 is slidably positioned in the assembly to telescope within tube 22 and a short sleeve 124 is secured to said shaft to serve as a bearing and to maintain alignment of the shaft within the assembly. The opposite end of shaft 122 bears plate 128 and stud 108, which as previously mentioned, is engaged in bore 106 of plate 104 when the stretcher is to be used.

The housing for the sliding lock assembly is formed by sleeve 112 and tube 116. End plate 134 is secured to tube 116 by set screws, threaded engagement. welding, etc. This end plate has a rim 136 which bears against the end of tube 116, a central bore for shaft 122 and a smaller bore in which is mounted pin 138. This pin is rigidly secured to plate 134 and projects a slight distance past the rear face of the plate. The pin is at the same radial spacing as bore 140 of plate 128 which is secured to shaft 122. Pin 138 serves as a rotational stop for plate 128 and thereby permits the pole extension 122 to be turned onto stud 108. In the illustration, pole extension 102 is slightly withdrawn from the assembly and plate 128 is unseated from engagement with pin 138. Shaft 122 and pole extension 102 which is secured thereto by stud 108 are freely rotatable within the assembly.

The housing of the lock assembly is surrounded by outer tube 110 which slips over tube 116. This outer tube projects rearwardly of the housing a distance greater than the travel of shaft 122 and serves as an alignment sleeve for the pole extension 102. Bracket 30 such as that previously described with regard to FIG. 1 is secured to tube 1 with set screws or welding. If desired, this attachment of bracket can be reinforced by mounting the bracket on a short sleeve which is slipped about tube 110 and welded or locked thereto. The bracket 30, as previously described, serves as a pivotal connection between the link member such as 24 of FIG. 1 and the base of the power unit, i.e., the lock assembly shown in FIG. 4. Tube 110 is locked to the housing of the lock assembly by set screws, not shown. or similar means which permits the removal of the tube for servicing of the unit. When tension is applied to the carpet by depressing the stretcher handle. the load is transmitted through bracket 30 to tube 1 10 and then to the housing of the assembly.

The sliding lock of the assembly is similar to that described in FIG. 1, however. no remote release means are provided. The lock comprises collar 142 and resilient means in the form of a compression spring 126. The spring is biased between the forward face of plate 134 and the rear face of collar 142. This collar has a finger 144 which projects into an aperture in tube 116. The collar is free to tilt about the detent of finger 144 in its aperture and spring 126 biases it forward. The lock permits the housing to be slipped or pulled forward on shaft 122 when the stretcher handle is moved upwardly since collar 142 releases the shaft for extension of the unit. When the stretcher handle is depressed, shaft 122 is locked by collar 142 and cannot retract in the housing. This occurs because the collar tilts slightly in a counterclockwise direction into a position where the lower rear edge and the upper forward edge of the hole in the collar bind against shaft 122. This action permits the lock unit to be used in a slip and lock action whereby the stretcher head can be pumped forward with the stretcher handle.

Collar 142 also has a manual release. Tubes 116 and have an elongated aperture in their top wall opposite collar 142. The collar is bored and tapped and bolt 146 is turned into this bore. When bolt 146 is moved rearwardly against the tension of spring 126, collar 142 is removed from its clamping engagement with shaft 122. The assembly of shaft 122 and attached pole extension can then be moved freely in the collar. The collar 142 can also be unlocked to release shaft 122 by raising the handle of the stretcher unit so that tube 22 is retracted in the assembly and piston 100 dependent thereon bears against the forward lip 148 on collar 142 and forces it rearwardly against the tension of spring 126. In this manner, the power unit can be slid forward on the pole extension by simply grasping the handle. raising the handle and pulling the unit forward. The weight of the pole extension will retain it in place and permit the shaft 122 to slide through the unlocked collar 142.

The length of the extension which can be achieved by the unit can be varied over a wide range. The lock collar provides an infinite number of extendible settings. Generally, for most applications, a slidable extension of from 5 to about 8 inches is adequate and will not require the use of an objectionably long housing assembly. Instead, it will be found that the unit is very compact and can be used in very tight quarters such as in hallways, etc.

Referring now to FIGS. 5 through 7, a preferred head assembly is illustrated. Plate 12, which is shown in FIG. 7, is formed of aluminum, magnesium, or alloys in which these metals are the principal components. The plate is generally triangular in shape and the ends can be rounded, as shown, or can be square. When the ends are square, additional end bearing edges are available for applying a tool such as a kicker stretcher to guide the head at an angle to the longitudinal axis of the stretcher.

At the trailing edge of the plate, shoe 150 is attached to the plate by bolts or screws 152 which rigidly secure the ends of the shoe to the plate. The plate is bored and tapped at 154, directly beneath the center of shoe 150. As shown in FIG. 6, screw 156 is turned into bore 154 so that advance of the screw raises the center of the shoe and retraction of the screw lowers the shoe. Tube 22 bears against shoe 150 and a fine degree of adjustment of the attitude of the head can be achieved. This 7 shoe eliminates the tendency of the head to dip, a characteristic of most stretchers wherein the front of the head tilts downwardly when a load is applied with the result that the front rows of teeth carry most of the applied load. The shoe 150 provides a bearing surface that prevents this dipping.

A view through the assembly of the. plate 12 and a preferred adapter 158 is shown in FIG. 6. The plate supports, on its under surface, rows of teeth 14. About 60 to 80 teeth can be placed in staggered positions along these rows at about one inch centers and, preferably, the plate is formed with an angular boss 13 about each of the teeth. A typical plate has a thickness of about five-sixteenth inch and bosses 13 extend downwardly about one-eighth to one-fourth inch about each tooth.

It is preferred to cast the plate 12 with teeth 14 placed in the mold so that the teeth are cast directly in the plate. It has been found that this method provides several advantages over the conventional manufacture in which the cast plates are bored and the teeth are pressed into the bores. First, the manufacture is substantially simplified since the tedious boring and fitting of the teeth is avoided. Instead, the teeth are placed directly into the mold which can be a typical foundry sand mold and the molten metal is then poured into the mold and flows about the base of the shank of the teeth. The teeth can readily be placed in a single operation by using a holder or jib that aligns and places the teeth in a single step. Preferably. the upper ends of the shanks of the teeth are burred, knurled or surface roughened to aid in their retention in the cast plate. The contraction of the metal as it cools about the teeth will securely retain the teeth.

Another significant advantage is that the molding tempers the base of the teeth and results in a plate in which the teeth are more resilient and resistant to breaking than are the teeth of a conventionally manufactured plate. The teeth are commonly manufactured of hardened stainless steel to attain maximum hardness and strength at the pointed ends. Typically, the teeth are about one-eighth inch in diameter and are formed of 4130 or 4140 stainless steel alloys and are heat treated for maximum hardness. The teeth are also chrome or nickel plated after fabrication. As a result, the teeth are brittle and it is a common experience for teeth to snap or shear from the plate. The casting of the molten metal about the shanks of the teeth, however, tempers these shanks since the molten metal is cast at temperatures from 1 100 to about 1400F. and slowly cools to room temperature. This tempering or annealing renders the shanks more ductile and sudden impacts which will shear teeth from a conventional head will only band the tempered shanks of the cast-in-plaee teeth. Any bent teeth can be readily straightened many times before the metal reaches its fatigue limit. Despite the tempering of the shanks, the sharp ends of the teeth retain all the original hardness and will wear equally to teeth that are conventionally placed in a plate after it has been cast. The tempering of the shanks extends a fraction of an inch, e.g.. about one-eighth to three-sixteenth inch, beneath the cast plate and thus extends over the length at which the maximum bending and shear stresses are applied. It has been further found that the use of the raised bosses l3 greatly improves this tempering of the teeth shanks, probably by increasing the contact between the molten metal and the shanks, thereby providing a more complete annealing or tempering" of the shanks.

As shown in FIG. 5, plate 12 is bored at at a forward position on its mid-line and is bored and threaded at 162 and 164, which are at outboard positions. FIG.

6 shows that a bolt 166 is placed in bore 160. This bolt passes through sleeve 168, spring washer 170 and washer 172 and is secured by nut 174. This arrange- I The adapter is also bored at to receive the end of tube 22 which can be locked in the bore by a set screw, pin or threaded connection to the adapter. A base plate 182 with a polished under, surface is preferably secured to the under surface of adapter 158 which is typically an aluminum casting. The adapter is bored transversely near its forward edge and the handle 20 isattached to' the adapter by pin 18 which passes through this transverse bore. Preferably, the bore is positioned on or slightly below the centerline of tube 22 so that the maximum lever advantage of the handle 20 can be obtained and so that the bending stresses on tube 22 are minimized. By placing the handle pivot at or near the centerline of tube 22, the compressive loading on the head will not have any significant component in a vertical direction when the handle is=fully depressed and substantially the entire load will be applied along the centerline of tube 22. This minimizes side forces on the rack and the alignment tube.

FIG. 7 is a sectional view along lines A-A' of FIG. 5.

This shows screw 184 which is turned in tapped bore.

164. The upper end of screw 184 is pinned to thumb nut 186 sothat the rotation of nut 186 raises or lowers the screw in bore 164. Screw 184 bears a wide head that serves as a vertical stop for teeth 14. These screws which are positioned at each side of plate 12 limit the penetration of teeth 14 into the carpet. When the screws are properly adjusted to the thickness of the carpet, the teeth will project only to the set thickness and will not scratch or dig into the floor beneath the carpet. These height adjustment screws are optional features and can be eliminated, particularly when the adapter secures the stretcher handle at the leading edge of. the. head as in FIG. 6 and/or when shoe 150 is used. These. latter features of construction insure that the leading edge of the head does not tilt but, instead, will retain the head parallel to the floor so that all the teeth .will

tendible bar 36 can be a rod or tube having a diameter 1 of about three-fourths inch. This element, as well as the locking collars are preferably surface hardened to a hardness of about,

I claim:

1. A carpet stretcher comprising: a head assembly bearing a plate having teeth for engagement of carpet and a rearwardly projecting head tube, a handle having one end thereof pivotally secured to a forward portion of said head assembly, a link member having one end pivotally secured to said handle at an intermediate point along the length thereof and its opposite end pivotally secured to a base tube assembly comprising a base tube, a receptacle tube concentrically carried at the forward end thereof and slidably receiving said head tube and terminating within said base tube with a bushing, and an extendible coupling assembly comprising a bar having its forward end telescopingly mounted within said receptacle and head tubes, lock means movable between lock and release positions carried by said base tube assembly and surrounding said bar of said coupling assembly, resilient means between said base tube and said lock means biasing said lock means into a locking position whereby said coupling assembly is restrained from retraction in said base tube but is freely extendible therefrom, remote lock release comprising lever means pivotally carried on said bushing within said base tube and a cable extending from said lever means externally of said base tube, and attachment means carried at the free end of said coupling assembly for removable attachment of carpet stretcher accesso ries.

2. The carpet stretcher of claim 1 wherein said lock means comprises a collar having one end pivotally carried by said base tube and a central aperture on an axis inclined to the face of the collar through which the inner end of said bar extends.

3. The carpet stretcher of claim 2 wherein said collar has a radial projection which is pivotally secured to said base tube.

4. The carpet stretcher of claim 3 wherein said radial projection extends through a slot in said base tube.

5. The carpet stretcher of claim 4 wherein said lock release means also includes resilient means biasing said lever into a retracted position from said lock means.

6. The carpet stretcher of claim 3 wherein said resilient means is a compression spring, coaxial with said bar, bearing against the rear face of said collar, and secured to said base tube by an annular spring retainer about said bar.

7. The carpet stretcher of claim 6 wherein said tube bears an abutment support forward of said slot with an adjustable abutment member carried thereon that is engaged by said radial projection of said collar whereby the alignment of said collar in said lock position can be controlled.

8. The carpet stretcher of claim 3 wherein said lever means of said lock release means is a bent washer pivotally mounted on said bushing and operative to urge the side of said resilient means and thereby move said collar to the release position.

9. The carpet stretcher of claim 8 wherein said handle carries trigger means and said cable means is connected from said trigger means to said lever means.

pivotally secured to said handle at an intermediate point along the length thereof and its opposite end pivotally secured to a base tube assembly comprising a base tube receiving said head tube fixedly secured thereto and an extendible coupling assembly comprising a bar having its forward end telescopingly mounted within said head tube, first lock means movable between lock and release positions carried by said base tube and surrounding said bar of said coupling assembly, first resilient means between said base tube and said first lock means biasing said first lock means into a locking position whereby said coupling assembly is restrained from retraction in said base tube but is freely extendible therefrom, remote lock release means comprising lever means pivotally carried on said bushing within said base tube and a cable extending from said lever means extemally of said base tube, second lock means also movable between lock and release positions positioned about said bar and within said base tube with a radial projection extending through an elongated slot of said base tube to a pivotal engagement with said opposite end of said link member, second resilient means biasing said second lock means into a lock position whereby up and down movement of said handle reciprocates said second lock means along said elongated slot and extends said coupling assembly in a stepping action, and attachment means carried at the free end of said coupling assembly for removable attachment of carpet stretcher accessories.

11. The carpet stretcher of claim 10 wherein said first and second lock means are first and second collars, each having a radial projection pivotally carried by said base tube and a central aperture on an axis inclined to the face of the collar through which the inner end of said bar extends.

12. The carpet stretcher of claim ll wherein said first and second resilient means are compression springs, coaxial with said bar, bearing against the rear faces of said first and second collars, and secured to said base tube by first and second annular spring retainers about said bar.

13. The carpet stretcher of claim 12 wherein each of said collars bears an axial projection on its forward face on the side opposite said radial projection, said axial projections being the forwardmost extension of said collar when in the lock position and thereby serving as abutment means for urging said collars into their release positions.

14. The carpet stretcher of claim 13 wherein said axial projection of the rearward collar is depressed against the rear face of said spring retainer of the forward collar and said axial projection of the forward collar is depressed against said lock release means when said handle is moved to its full up position and said collars are thereby moved into their release positions.

15. The carpet stretcher of claim 12 wherein said lock release means includes lever means pivotally mounted to said bushing and operative to engage the axial projection of said forward collar and tilt it against the bias of its compression spring and thereby move the forward collar into its release position.

Claims

1. A carpet stretcher comprising: a head assembly bearing a plate having teeth for engagement of carpet and a rearwardly projecting head tube, a handle having one end thereof pivotally secured to a forward portion of said head assembly, a link member having one end pivotally secured to said handle at an intermediate point along the length thereof and its opposite end pivotally secured to a base tube assembly comprising a base tube, a receptacle tube concentrically carried at the forward end thereof and slidably receiving said head tube and terminating within said base tube with a bushing, and an extendible coupling assembly comprising a bar having its forward end telescopingly mounted within said receptacle and head tubes, lock means movable between lock and release positions carried by said base tube assembly and surrounding said bar of said coupling assembly, resilient means between said base tube and said lock means biasing said lock means into a locking position whereby said coupling assembly is restrained from retraction in said base tube but is freely extendible therefrom, remote lock release comprising lever means pivotally carried on said bushing within said base tube and a cable extending from said lever means externally of said base tube, and attachment means carried at the free end of said coupling assembly for removable attachment of carpet stretcher accessories.

10. A carpet stretcher comprising: a head assembly bearing a plate having teeth for engagement of carpet and a rearwardly projecting head tube, a handle having one end thereof pivotally secured to a forward portion of said head assembly, a link member having one end pivotally secured to said handle at an intermediate point along the length thereof and its opposite end pivotally secured to a base tube assembly comprising a base tube receiving said head tube fixedly secured thereto and an extendible coupling assembly comprising a bar having its forward end telescopingly mounted within said head tube, first lock means movable between lock and release positions carried by said base tube and surrounding said bar of said coupling assembly, first resilient means between said base tube and said first lock means biasing said first lock means into a locking position whereby said coupling assembly is restrained from retraction in said base tube but is freely extendible therefrom, remote lock release means comprising lever means pivotally carried on said bushing within said base tube and a cable extending from said lever means externally of said base tube, second lock means also movable between lock and release positions positioned about said bar and within said base tube with a radial projection extending through an elongated slot of said base tube to a pivotal engagement with said opposite end of said link member, second resilient means biasing said second lock means into a lock position whereby up and down movement of said handle reciprocates said second lock means along said elongated slot and extends said coupling assembly in a stepping action, and attachment means carried at the free end of said coupling assembly for removable attachment of carpet stretcher accessories.

12. The carpet stretcher of claim 11 wherein said first and second resilient means are compression springs, coaxial with said bar, bearing against the rear faces of said first and second collars, and secured to said base tube by first and second annular spring retainers about said bar.